94 research outputs found

    Impact of climate on pipe failure: predictions of failures for drinking water distribution systems

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    The integrity of drinking water distribution systems (DWDS) may be influenced by climate change. Using the statistical relations between failure frequencies and weather conditions described in our previous work (Wols & Van Thienen 2014a), a methodology is proposed to assess the effect of climate change on future DWDSs. The effect of climate change is combined with the evolution of the DWDS. This analysis can be conducted for any DWDS, for which historical failure registrations and weather parameters are available. The proposed methodology can therefore assist in the construction and maintenance planning of DWDSs. The methodology has been worked out for the Dutch drinking water distribution network. The results show that failures in networks with high AC proportions will increase as a result of expected climate change in the Netherlands, whereas failures in networks with high PVC and GCI proportions will even slightly reduce

    Critical Design Criteria for Standard, Truncated, and Parallel Chords Cold-Formed Steel Trusses

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    The design of cold-formed steel trusses can be a very complicated and long repetitive process involving up to 28 load combinations added to serviceability checks depending on the design standards being used. This process is particularly tedious if a near optimal solution is required. Additionally, the risk of introducing human errors is usually quite high as it is a process often done by hand. FRAMECAD Structure is a niche software solution born from the desire to provide a complete solution for constructing with cold-formed steel by a company selling roll-forming machines. FRAMECAD Structure specialises on automating the calculations and design of cold-formed steel framed panels, trusses and joists with minimal user input. However, computational-oriented software applications are often not optimised for performance, hence the inefficiency in obtaining a design solution, i.e. the proposed solution is either not optimal or takes a considerable time to compute. To provide guidelines on the design of cold-formed trusses, this research uses FRAMECAD Structure to study which design parameters are critical and what impact they have on optimising the design outcome

    Review of applications of SIMDEUM, a stochastic drinking water demand model with small temporal and spatial scale

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    Many researchers have developed drinking water demand models with various temporal and spatial scales. A limited number of models are available at a temporal scale of one second and a spatial scale of a single home. Reasons for building these models were described in the papers in which the models were introduced, along with a discussion on potential applications. However, the predicted applications are seldom re-examined. As SIMDEUM, a stochastic end-use model for drinking water demand, has often been applied in research and practice since it was developed, we are reexamining its applications in this paper. SIMDEUM’s original purpose was to calculate maximum demands in order to be able to design self-cleaning networks. Yet, the model has been useful in many more applications. This paper gives an overview of the many fields of application of SIMDEUM and shows where this type of demand model is indispensable and where it has limited practical value. This overview also leads to an understanding of requirements on demand models in various applications

    Review of applications for SIMDEUM, a stochastic drinking water demand model with a small temporal and spatial scale

    Get PDF
    Many researchers have developed drinking water demand models with various temporal and spatial scales. A limited number of models is available at a temporal scale of 1 s and a spatial scale of a single home. The reasons for building these models were described in the papers in which the models were introduced, along with a discussion on their potential applications. However, the predicted applications are seldom re-examined. SIMDEUM, a stochastic end-use model for drinking water demand, has often been applied in research and practice since it was developed. We are therefore re-examining its applications in this paper. SIMDEUM's original purpose was to calculate maximum demands in order to design self-cleaning networks. Yet, the model has been useful in many more applications. This paper gives an overview of the many fields of application for SIMDEUM and shows where this type of demand model is indispensable and where it has limited practical value. This overview also leads to an understanding of the requirements for demand models in various applications

    Climate adaptation of interconnected infrastructures: a framework for supporting governance

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    Infrastructures are critical for human society, but vulnerable to climate change. The current body of research on infrastructure adaptation does not adequately account for the interconnectedness of infrastructures, both internally and with one another. We take a step toward addressing this gap through the introduction of a framework for infrastructure adaptation that conceptualizes infrastructures as complex socio-technical “systems of systems” embedded in a changing natural environment. We demonstrate the use of this framework by structuring potential climate change impacts and identifying adaptation options for a preliminary set of cases—road, electricity and drinking water infrastructures. By helping to clarify the relationships between impacts at different levels, we find that the framework facilitates the identification of key nodes in the web of possible impacts and helps in the identification of particularly nocuous weather conditions. We also explore how the framework may be applied more comprehensively to facilitate adaptation governance. We suggest that it may help to ensure that the mental models of stakeholders and the quantitative models of researchers incorporate the essential aspects of interacting climate and infrastructure systems. Further research is necessary to test the framework in these contexts and to determine when and where its application may be most beneficial.Infrastructure Networks Climate Adaptation and Hotspots. Knowledge for Climate Progra

    Effects of β-alanine supplementation on exercise performance: a meta-analysis

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    Due to the well-defined role of β-alanine as a substrate of carnosine (a major contributor to H+ buffering during high-intensity exercise), β-alanine is fast becoming a popular ergogenic aid to sports performance. There have been several recent qualitative review articles published on the topic, and here we present a preliminary quantitative review of the literature through a meta-analysis. A comprehensive search of the literature was employed to identify all studies suitable for inclusion in the analysis; strict exclusion criteria were also applied. Fifteen published manuscripts were included in the analysis, which reported the results of 57 measures within 23 exercise tests, using 18 supplementation regimes and a total of 360 participants [174, β-alanine supplementation group (BA) and 186, placebo supplementation group (Pla)]. BA improved (P = 0.002) the outcome of exercise measures to a greater extent than Pla [median effect size (IQR): BA 0.374 (0.140–0.747), Pla 0.108 (−0.019 to 0.487)]. Some of that effect might be explained by the improvement (P = 0.013) in exercise capacity with BA compared to Pla; no improvement was seen for exercise performance (P = 0.204). In line with the purported mechanisms for an ergogenic effect of β-alanine supplementation, exercise lasting 60–240 s was improved (P = 0.001) in BA compared to Pla, as was exercise of >240 s (P = 0.046). In contrast, there was no benefit of β-alanine on exercise lasting <60 s (P = 0.312). The median effect of β-alanine supplementation is a 2.85% (−0.37 to 10.49%) improvement in the outcome of an exercise measure, when a median total of 179 g of β-alanine is supplemented
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