Scalable Ray Tracing Using the Distributed FrameBuffer

Image‐ and data‐parallel rendering across multiple nodes on high‐performance computing systems is widely used in visualization to provide higher frame rates, support large data sets, and render data in situ. Specifically for in situ visualization, reducing bottlenecks incurred by the visualization and compositing is of key concern to reduce the overall simulation runtime. Moreover, prior algorithms have been designed to support either image‐ or data‐parallel rendering and impose restrictions on the data distribution, requiring different implementations for each configuration. In this paper, we introduce the Distributed FrameBuffer, an asynchronous image‐processing framework for multi‐node rendering. We demonstrate that our approach achieves performance superior to the state of the art for common use cases, while providing the flexibility to support a wide range of parallel rendering algorithms and data distributions. By building on this framework, we extend the open‐source ray tracing library OSPRay with a data‐distributed API, enabling its use in data‐distributed and in situ visualization applications.     

Effects of α-Radiolysis on Leaching of a Nuclear Waste Glass

The effects of α-radiolysis on leaching were studied in compositionally identical Pu-doped waste glass samples which were prepared at different α-activities (dose rates) by varying the ²³⁹Pu/²³⁸Pu isotopic ratio in the Pu dopant. The results of 14-, 28-, and 56-d static leach tests at 40°C, in both deionized water and brine solution, indicate that α-radiolysis at the samplelsolution interface increased Pu and Si release by a factor of ≅3.     

Projectification in Western economies: A comparative study of Germany,Norway and Iceland

Projectification has become a buzzword. Although repeated claims of an increasing projectification were often supported by illustrative, case-based evidence, a systematic and complete measurement of projectification of an entire economy - including all sectors and project types - is still missing. A more precise and reliable measurement of the degree of projectification can be helpful for underlying the importance of project management both for research and practice. This paper presents the results of a comparative study in three Western economies: Germany, Norway, and Iceland. Projectification was measured as the share of project work on total work. This allows for a systematic comparison between countries and sectors. We show that although differences exist among the countries regarding their size and industry structure, the share of project work in advanced economies seems to be about one third. However, comparing the different countries demonstrates that important differences exist for individual sectors.     

Project complexity and team-level absorptive capacity as drivers of project management performance

Many believe that project complexity reduces project management performance. However, so far research has failed to establish this causal relationship conclusively. We extend research on project complexity by introducing the concept of team-level absorptive capacity and by studying its role as mediator between project complexity and project management success. Applying structural equation modelling to a sample of 285 respondents, we find an unequivocal, direct and positive statistical association between project complexity and delays and overspending. Further, we show that team-level absorptive capacity is critical for successful project management, but also that absorptive capacity can only partially offset the harmful impact of project complexity. Beyond adding to project management theory, the paper contributes to the wider management literature. We establish complexity as an antecedent of absorptive capacity and demonstrate how each dimension of absorptive capacity has unique determinants and outcomes.     

Ventilation rates in recently constructed U.S. school classrooms

Low ventilation rates (VRs) in schools have been associated with absenteeism, poorer academic performance, and teacher dissatisfaction. We measured VRs in 37 recently constructed or renovated and mechanically ventilated U.S. schools, including LEED and EnergyStar‐certified buildings, using CO₂ and the steady‐state, build‐up, decay, and transient mass balance methods. The transient mass balance method better matched conditions (specifically, changes in occupancy) and minimized biases seen in the other methods. During the school day, air change rates (ACRs) averaged 2.0±1.3 hour^?1, and only 22% of classrooms met recommended minimum ventilation rates. HVAC systems were shut off at the school day close, and ACRs dropped to 0.21±0.19 hour^?1. VRs did not differ by building type, although cost‐cutting and comfort measures resulted in low VRs and potentially impaired IAQ. VRs were lower in schools that used unit ventilators or radiant heating, in smaller schools and in larger classrooms. The steady‐state, build‐up, and decay methods had significant limitations and biases, showing the need to confirm that these methods are appropriate. Findings highlight the need to increase VRs and to ensure that energy saving and comfort measures do not compromise ventilation and IAQ.     

The SG2 algorithm for a fast and accurate computation of the position of the Sun for multi-decadal time period

The solar position algorithm (SPA) is a very accurate but slow algorithm for the computation of the Sun position with respect to an observer at ground surface. We compare the results of three fast algorithms to the SPA and establish their performances. We propose a new algorithm SG2 that is faster than the three others and offers the same level of accuracy than the most accurate, i.e., maximum error in solar vector of order of 10″, for a multi-decadal time period, with an example of a 50-year period: 1980–2030. This performance is achieved by devising approximations of the original equations of the SPA to decrease the number of operations. This yields a decrease in accuracy that is controlled and bounded. The mathematical tools permitting to determine these approximations with a selected uncertainty level are described.     

Erratum zu: Entwicklung eines probabilistischen Modells zur Vorhersage von Schnittkräften beim unterbrochenen Drehen von Inconel 718

Forschung im Ingenieurwesen - In diesem Artikel wird die Entwicklung probabilistischer Modelle mittels Bayesianischen Inferenz durch ein MCMC-Verfahren zur Vorhersage von Tangential- und...     

Horizontal forces in steel structures tested in fire

Fire tests carried out on the eight-storey steel framed building at the Building Research Establishment’s Cardington laboratory have shown that the connections are subject to large axial force. These forces are the result of thermal movements of the structure during heating and cooling and in some cases can result in failure of the structure. This paper describes a fire test carried out on the steel frame at Cardington on 16th January 2003 and a fire test carried out on a structure in Ostrava on 16th June 2006. In both cases the tests were designed to measure the forces generated in the connections.     

Temperatures during fire tests on structure and its prediction according to Eurocodes

The paper reports on an experimental programme to investigate the global structural behaviour of a compartment in the three-storey steel frame building in a plant of the Mittal Steel Ostrava exposed to fire before demolition. The research project of the Czech Technical University in Prague was focussed on the examination of the temperature development within the various unprotected structural elements and its connections, the corresponding distribution of horizontal forces and the behaviour of the laterally unrestrained beams during the natural fire. The experiment also allowed studying of the heating of external elements, the influence of connection in a wall of sandwich panels, the temperature development in light timber-based panel and the degradation of the timber concrete composite element. Before the compartment fire, a local fire was prepared to verify the models of the temperature development in an unprotected column. The comparisons to the simplified calculations by European standards are included in the text to show their strong and weak points in prediction of temperatures of gas and structural elements during fire.