Recent technological advances and the ever-greater developments in sensing and computing continue to provide new ways of understanding our daily mobility. Smart devices such as smartphones or ...smartwatches can, for instance, provide an enhanced user experience based on different sets of built-in sensors that follow every user action and identify its environment. Monitoring solutions such as these, which are becoming more and more common, allows us to assess human behavior and movement at different levels. In this article, extended from previous work, we focus on the concept of human mobility and explore how we can exploit a dataset collected opportunistically from multiple participants. In particular, we study how the different sensor groups present in most commercial smart devices can be used to deliver mobility information and patterns. In addition to traditional motion sensors that are obviously important in this field, we are also exploring data from physiological and environmental sensors, including new ways of displaying, understanding, and analyzing data. Furthermore, we detail the need to use methods that respect the privacy of users and investigate the possibilities offered by network traces, including Wi-Fi and Bluetooth communication technologies. We finally offer a mobility assistant that can represent different user characteristics anonymously, based on a combination of Wi-Fi, activity data, and graph theory.
We present a characterization of contact velocity skin effect (VSEC), which is a major velocity- and efficiency-limiting effect at a railgun's sliding contact. Despite enormous contact forces, the ...armature remains separated from the rail by a thin layer, 4 to 12 A thick. Evidence suggests VSEC is also the primary mechanism responsible for the contact voltage drop. VSEC effects are seen in both electromagnetic launcher (EML) efficiency and breech voltage. We compare theoretical predictions of system efficiency and breech voltage to experimental measurements for both a conventional and an augmented railgun. The characterization of VSEC extends our previous theoretical work in this area and provides new insights into the physics of EML operation, especially with regards to the armature and sliding contact. VSEC is a significant energy loss mechanism and heat source, possibly contributing to contact erosion and transition. We propose a similar VSEC mechanism to explain velocity saturation and efficiency roll-off in plasma and hybrid armature railguns, as well as arc restrike.
This study is the first part of a larger investigation into the fire behaviour of green façades. In this study, the currently known international research status on this topic is presented and ...discussed. In addition, the flammability of green façades is investigated through 43 fire tests on a medium scale according to the SBI (Single Burning Item) test method EN 13823. The focus of the investigation was placed on climbing plants. A total of 25 different plant species were investigated. A comparison of the heat release rate of all the investigated vital plants shows similar behaviour. In the course of exposure, there are short peaks in the heat release rate. These peaks are “flare-ups” that occur when parts of the plants dry out due to exposure to the flame and then ignite. The plant species itself had no substantial influence on fire behaviour. Horizontal fire spread occurred to a very limited extent within the investigations of vital plants. They were self-extinguishing. The significant factor in the assessment of flammability is the moisture content of the plants. With dried plants, an abrupt heat release occurs at the beginning. Dried-out plants, as well as unmaintained plants with a high content of deadwood, represent the most critical case.
Graphical Abstract
This study investigates whether timber surfaces that are initially exposed to fire or partially protected timber components can lead to a more critical fire exposure on the façade. Five full-scale ...fire tests were carried out. Three tests with a square compartment (4.5 × 4.5 m
2
) and two with a double-width compartment (4.5 × 9 m
2
). The tests were conducted with a high fire load density (1085 MJ/m
2
). While the first test was carried out in a non-combustible compartment, the exposed timber surfaces were subsequently increased in the other tests. The measured compartment gas temperature, heat release rate, temperature on the façade, flame heights along the façade, heat flux and velocities along the façade are presented in this publication. The influence of exposed or only initially protected timber surfaces on the fire impact on the façade is investigated with the help of these results. Finally, these findings are presented and compared with the results of other internationally conducted fire tests from literature. Additional structural fire load leads to an increase in temperatures on the façade. However, there is no significant difference in flame height between the tests. Another result was that an exposed mass timber ceiling leads to higher heat fluxes on the façade than an exposed mass timber wall.
Graphical Abstract
The design and operation of 40- and 70-mm-bore solid-projectile helical electromagnetic launchers is presented and discussed. The 70-mm launcher demonstrates the first reported magnetically levitated ...zero hoop-stress armature and is tested in both constant- and variable-gradient stators. The theory of variable-gradient launcher operation is presented and shows that a properly designed variable-gradient launcher has efficiency independent of velocity but dependent on a new parameter called the launcher impedance constant. The variable-gradient launcher can also behave as an ideal launcher operating at 100% of its maximum theoretical efficiency independent of velocity if the ratio of the system resistance and impedance constant meets other conditions. This investigation also introduces the concept of launcher impedance and shows that variable-gradient launchers with high impedance are desirable in terms of efficiency.
We address the problem of shock wave formation in uncoordinated highway traffic. First, we identify the combination of heavy traffic and small traffic perturbations or unexpected driver actions as ...the main causes of highway traffic jams. Then we introduce a novel distributed communication protocol that enables us to eliminate upstream shock wave formation even with low system penetration rates. Based on traffic information ahead, we propose a Cooperative Advanced Driver Assistance System (CADAS) that recommends non-intuitive velocity reductions in order to redistribute traffic more uniformly thereby eliminating traffic peaks. Simulation results show that CADAS significantly increases the average velocity and therewith reduces the overall travel time and avoids unnecessary slowdowns.
This study investigates five fire stop variants used to limit the spread of fire on wooden façades. For this purpose, five fire tests using various types of wooden façade claddings and different fire ...stops were conducted as full-scale tests and compared to the existing findings. The influences and interactions between the material qualities of the external wall behind the façade cladding, the construction type of the wooden façade cladding, the design of the substructure, the depth of the ventilation gap, and the design of the fire stops were investigated. In evaluating the fire stops, the design of the interior corners, the joint design, and the influence of thermal expansion were examined. Finally, design proposals for the design of fire stops at wooden façades in order to limit the spread of fire were derived based on this evaluation. The outlook presents further needs that need to be investigated in the future in order to clarify undiscussed aspects or points that were ultimately not evaluated within the scope of this study.
Graphical Abstract
The high-efficiency mode of electromagnetic launcher (EML) operation is investigated. The high-efficiency mode for some launchers is achieved when the EML is operated in zero exit current (ZC) mode. ...Several power supply strategies to achieve high-efficiency ZC mode are presented. The investigation defines the ideal high-efficiency power supply for high-efficiency ZC mode launcher operation. The ideal power supply, in conjunction with a well-designed EML, will approximate an ideal launcher. The principles presented apply to all noninduction EMLs even though the discussion is limited to conventional railguns and helical launchers and augmented railguns and high-efficiency helical launchers. Theoretical predictions are in good agreement with experimental measurements.
A wheat phenology model based on the effects of temperature, vernalization and photoperiod was developed by introducing a temperature response function for development rate and vernalization, and the ...concepts of physiological development days and physiological vernalization days. This model also includes the prediction of the development of leaves, internodes and tillers. It gives EC stage values, i.e. the decimal code defined by Zadoks, J. C., Chang T. T. and Konzak, C. F. (1974)
Weed Research
14, 415–421, as outputs. The model was parameterized and tested using observation data from The Netherlands, north and south Germany. Simulation results show that the phenology model can be used to simulate development stages for different wheat varieties with acceptable accuracy. The model can be extended to other cereal crops.
Begrünte Fassaden liegen im Trend. Die Brandausbreitung entlang der Fassade stellt grundsätzlich weltweit eines der kritischsten Brandszenarien dar, und Pflanzen sind zusätzliche brennbare ...Materialien. Der Einfluss begrünter Fassaden auf die Brandweiterleitung entlang der Fassade ist folglich nicht zu vernachlässigen. Allerdings steht nur wenig Forschung zu diesem Thema zur Verfügung. Dies soll das Forschungsvorhaben FireSafeGreen ändern. Haupteinflussfaktor auf das Brandverhalten von Pflanzen ist der Feuchtigkeitsgehalt. Die Pflanzenart selbst spielt eine untergeordnete Rolle in Bezug auf das Brandverhalten. Eine Kombination aus Holz‐ und begrünter Fassade führt unter Berücksichtigung einiger Randbedingungen nicht zu einer Entzündung der dahinterliegenden Holzfassade. Grundsätzlich sind die angemessene Pflege und Wartung die maßgebenden Faktoren für brandsichere begrünte Fassaden.
Translation
Basic principles for a fire‐safe application of green façades on multi‐storey buildings.
Green façades are in vogue. Fire spread along the façade is generally one of the most critical fire scenarios worldwide, and plants are additional combustible materials. The influence of green façades on fire propagation along the façade should therefore not be neglected. However, little research is available on this topic. The FireSafeGreen research project aims to change this. The main factor influencing the fire behaviour of plants is the moisture content. The plant species itself plays a subordinate role in terms of fire behaviour. A combination of wooden and green façade does not lead to an ignition of the wooden façade under consideration of some boundary conditions. In principle, appropriate care and maintenance are the key factors for fire‐safe green façades.
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