921 research outputs found

    Viscosity properties of bimodal bitumen emulsions: new approach

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    The emulsions used in the manufacture of half warma sphat should contain very little water in their formulation. Conventional monomodal emulsions have a maximum dispersed phase concentration, Ď•, of 0.69. Recent research in this field is focused on the development of concentrated emulsions, Ď• = 0.70-0.74, or highly concentrated emulsions, Ď• >0.74. The concentrated or highly concentrated emulsions have little water in their formulation, <30%, but consequently have very high viscosities. This article summarizes the main conclusions related with the design, formulation and viscosity of bimodal concentrated bitumen emulsions.To formulate a bimodal emulsion is necessary to firstly manufacture two monomodal emulsion with a controlled drop size distribution from 1 and 5 ÎĽm respectively. These emulsions should be prepared with a system able to control the final drop size. In this study we have used the HIPR (High Internal Phase Ratio) procedure. The emulsions formulated in this paperare characterized by having viscosities up to ten time slower than their small monomodal size counterparts

    Assessment of the impact of occupants’ behavior and climate change on heating and cooling energy needs of buildings

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    Energy performance of buildings is a worldwide increasing investigated field, due to ever more stringent energy standards aimed at reducing the buildings’ impact on the environment. The purpose of this paper is to assess the impact that occupant behavior and climate change have on the heating and cooling needs of residential buildings. With this aim, data of a questionnaire survey delivered in Southern Italy were used to obtain daily use profiles of natural ventilation, heating, and cooling, both in winter and in summer. Three climatic scenarios were investigated: The current scenario (2020), and two future scenarios (2050 and 2080). The CCWorldWeatherGen tool was used to create the weather files of future climate scenarios, and DesignBuilder was applied to conduct dynamic energy simulations. Firstly, the results obtained for 2020 demonstrated how the occupants’ preferences related to the use of natural ventilation, heating, and cooling systems (daily schedules and temperature setpoints) impact on energy needs. Heating energy needs appeared more affected by the heating schedules, while cooling energy needs were mostly influenced by both natural ventilation and usage schedules. Secondly, due to the temperature rise, substantial decrements of the energy needs for heating and increments of cooling energy needs were observed in all the future scenarios where in addition, the impact of occupant behavior appeared amplified.This research was funded by the Calabria Region Government with the Gianmarco Fajilla's Ph.D. scholarship (POR Calabria FSE/FESR 2014-2020) grant number H21G18000170006. A part of this publication has received funding from Secretaria Nacional de Ciencia y Tecnologia (SENACYT) under the project code FID18-056. This work was partially funded by the Ministerio de Ciencia, Innovacion y Universidades de Espana (RTI2018-093849-B-C31 -MCIU/AEI/FEDER, UE). This work was partially funded by the Ministerio de Ciencia, Innovacion y Universidades -Agencia Estatal de Investigacion (AEI, RED2018-102431-T). This work is partially supported by ICREA under the ICREA Academia program

    Rammed earth walls in Mediterranean climate: material characterization and thermal behaviour

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    Rammed earth is considered a very sustainable construction system due to its low embodied energy, long service life and high recyclability. However, authors found that there is a lack of experimental results at real scale regarding rammed earth thermal behaviour. For this reason, this paper is first focused on the characterization of two different types of earth in order to check the suitability of being used in rammed earth walls. After the characterization, two experimental cubicle-shape buildings were built in Barcelona and Puigverd de Lleida (Spain) in order to test the thermal behaviour of their walls in two different climatic conditions. Temperature profiles inside walls have been monitored using thermocouples and temperature profile of southern walls was analysed in free floating conditions during summer and winter periods of 2013. Results show that thermal amplitude from outside to inside temperatures are decreased by rammed earth walls, achieving constant temperatures in inner surface of southern walls.Peer ReviewedPostprint (published version

    Characterization of granular phase change materials for thermal energy storage applications in fluidized beds

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    This work investigates commercially available granular phase change materials (PCMs) with different transition temperatures for the use of thermal-energy storage systems in fluidized beds. The hydrodynamic characteristics of granular PCMs were tested in cylindrical-3D and planar-2D fluidized beds. The density, particle size distribution and angle of repose were measured for various PCM materials. Further attrition studies were conducted with changes in particle surface from abrasion, which were characterized using a Scanning Electron Microscope (SEM). The results indicate that some materials with smaller particle size and thinner supporting structure can lose the paraffin during the fluidization process, when paraffin is in a liquid state. As a consequence, the particles agglomerate, and the bed defluidizes. For all of the tested materials, only GR50 (with a transition temperature of 50 degrees C) properly fluidizes when the paraffin is in the liquid state and has shown to endure >75 h of continuous operation and 15 melting-solidification cycles in a fluidized bed. Additional differential scanning calorimetry (DSC) measurements of the cycled particles did not show a decrease in energy storage capacity of the granular PCM, which corroborates that there is no loss of material after >75 h of fluidization. (C) 2016 Elsevier Ltd. All rights reserved.The work is partially funded by the Spanish government (ENE2010-15403, ENE2011-22722 and ENE2015-64117-C5-1). The authors would like to thank the Catalan Government for the quality accreditation to their research groups GREA (2014 SGR 123). The study that led to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 657466 (INPATH-TES)

    Deep Emissions Reductions and Mainstreaming of Mitigation and Adaptation: Key Findings

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    Climate policy "mainstreaming", "proofing" and "integration" are concepts that are increasingly appearing in a range of EU policy discussions, including those concerning the 2014-2020 Multi-Annual Financial Framework (MFF). They reflect the view that all policy sectors need to play a part in both reducing emissions and increasing resilience to unavoidable climate impacts. Broadly defined, mainstreaming involves including climate considerations in policy processes, improving the consistency among policy objectives, and where necessary, giving priority to climate-related goals above others. Although often couched in technical language, profound political challenges, at multiple levels of governance, lie at the heart of the mainstreaming agenda. The RESPONSES project analysed how far adaptation and mitigation was being mainstreamed in EU policies, and assessed the potential opportunities and limits for the future

    Impact of functional status on outcomes of simultaneous pancreas-kidney transplantation: Risks and opportunities for patient benefit

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    Background. The impact of functional status on survival among simultaneous pancreas-kidney transplant (SPKT) candidates and recipients is not well described. Methods. We examined national Scientific Registry of Transplant Recipients (SRTR) data for patients listed for SPKT in the United States (2006-2019). Functional status was categorized by center-reported Karnofsky Performance Score (KPS). We used Cox regression to quantify associations of KPS at listing and transplant with subsequent patient survival, adjusted for baseline patient and transplant factors (adjusted hazard ratio,(95% LCL)aHR(95%UCL)). We also explored time-dependent associations of SPKT with survival risk after listing compared with continued waiting in each functional status group. Results. KPS distributions among candidates (N = 16 822) and recipients (N = 10 316), respectively, were normal (KPS 80-100), 62.0% and 57.8%; capable of self-care (KPS 70), 23.5% and 24.7%; requires assistance (KPS 50-60), 12.4% and 14.2%; and disabled (KPS 10-40), 2.1% and 3.3%. There was a graded increase in mortality after listing and after transplant with lower functional levels. Compared with normal functioning, mortality after SPKT rose progressively for patients capable of self-care (aHR,(1.00)1.18(1.41)), requiring assistance (aHR,(1.06)1.31(1.60)), and disabled (aHR,(1.10)1.55(2.19)). In time-dependent regression, compared with waiting, SPKT was associated with 2-fold mortality risk within 30 days of transplant. However, beyond 30 days, SPKT was associated with reduced mortality, from 52% for disabled patients (aHR,(0.26)0.48(0.88)) to 70% for patients with normal functioning (aHR,(0.26)0.30(0.34)). Conclusions. While lower functional status is associated with increased mortality risk among SPKT candidates and recipients, SPKT can provide long-term survival benefit across functional status levels in those selected for transplant

    Independence in CLP Languages

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    Studying independence of goals has proven very useful in the context of logic programming. In particular, it has provided a formal basis for powerful automatic parallelization tools, since independence ensures that two goals may be evaluated in parallel while preserving correctness and eciency. We extend the concept of independence to constraint logic programs (CLP) and prove that it also ensures the correctness and eciency of the parallel evaluation of independent goals. Independence for CLP languages is more complex than for logic programming as search space preservation is necessary but no longer sucient for ensuring correctness and eciency. Two additional issues arise. The rst is that the cost of constraint solving may depend upon the order constraints are encountered. The second is the need to handle dynamic scheduling. We clarify these issues by proposing various types of search independence and constraint solver independence, and show how they can be combined to allow dierent optimizations, from parallelism to intelligent backtracking. Sucient conditions for independence which can be evaluated \a priori" at run-time are also proposed. Our study also yields new insights into independence in logic programming languages. In particular, we show that search space preservation is not only a sucient but also a necessary condition for ensuring correctness and eciency of parallel execution

    A framework for integrating sustainability estimation with concepts of rules of building measurement

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    BIM promises improvement in project delivery efficiencies such as reduction in costs and errors and timely completion. Benefits are also expected in sustainable construction aspect with research efforts being extended to sustainable design and assessment. These efforts are still been explored for the purposes of unifying quantification methodologies, the standardisation of system boundaries, terms of references and sustainability measures. Embodied energy and CO2 are two common measures that have been widely used in the construction sector. Although a number calculation system exists, they are not useful to the iterations that occur at the early stages of the project life cycle. At the procurement stage, professionals often rely on schedules and bill of quantities with no reference to sustainability credentials. It is therefore important to integrate sustainability measure with concepts in standard measurement methods. As such, we propose a framework to integrate sustainability credential with the concepts in rule of building measurement. We conclude that this framework can be applicable to any rule of building measurement and it is implementable in a computer programmable environment
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