Automated space layout planning for environmental sustainability

There is a growing global interest in low/zero carbon buildings in response to the increased CO2 in the atmosphere, nearly half of which comes from building energy consumption. Buildings are built for a considerably longer lifespan and enhancing energy efficiency in buildings can play a significant role in reducing CO2 emissions. Energy efficiency features need to be incorporated at the earliest, as alterations to the design at latter stages may prove to be difficult and sometimes expensive. Building design is concerned with satisfying various objectives (e.g. cost, efficiency of a space layout, energy consumption), which are sometimes in conflict with each other. Performance of various indicators, therefore, needs to be assessed as a whole rather than in isolation. Space layout planning is considered as the starting point of building design. Most performance indicators; i.e. cost, energy efficiency, etc. are closely linked with the layout. Researchers have attempted at automating space layout planning since the 1960s with a view to effectively search the solution space. Diverse approaches are adopted in space layout planning that ranges from the analysis of spatial proximity to the application of ‘space syntax’ theory. Developments in whole building energy simulation and integration of simulation in the design process imply that the search for optimum space layout could be better guided by incorporating detailed-based simulation as response generators as opposed to the ones with a simplified representation of the problem domain. This paper describes a framework for sustainable space layout planning that uses evolutionary computation methods to search the solution space. Whole building simulation programs are used as response generators to guide the search for energy efficient layouts. The integrated approach enables the consideration of energy consumption, in addition to the geometry and topology, for decision making during space layout planning

Evolutionary building layout optimisation

Space layout planning (SLP) is the organisation of functional/living spaces (spatial units-SUs) and corridors/access paths of a building satisfying requirements (e.g. accessibility, adjacency etc.) to achieve design goals (e.g. minimising unutilised space and travelling cost). Out of many ways of arranging SUs, a human designer may consider only a handful of alternatives due to resource limitations (e.g. time and effort). To facilitate this task, decision support for SLP design can be obtained using computer technology. Despite being highly combinatorial, many attempts have been made to automate SLP. However in the majority of these, the SUs are arranged in a fixed building footprint/boundary, which may limit exploration of the entire solution space. Thus, it is aimed to develop a space layout optimisation system that allows SUs to position themselves in a building site to satisfy design goals. The objectives of the research are to: understand architectural SLP and optimisation; assess the need for automation of SLP optimisation; explore methods to formulate the SLP optimisation problem; develop a prototype system to optimise SLP based on building design guidelines, and evaluate performance for its strengths and weaknesses using case studies. As early stages of building design are found to be most e ective in reducing the environmental impact and costs, it is also aimed to make provisions for integrating these aspects in SLP. To address the first three objectives, a literature review was conducted. The main finding of this was the current need for an optimisation tool for SLP. It also revealed that genetic algorithms-GA are widely used and show promise in optimisation. Then, a prototype space layout optimisation system (Sl-Opt) was developed using real-valued GA and was programed in JavaR. Constrained optimisation was employed where adjacency and accessibility needs were modelled as constraints, and the objective was to minimise the spread area of the layout. Following this, using an office layout with 8 SUs, Sl-Opt was evaluated for its performance. Results of the designed experiment and subsequent statistical tests showed that the selected parameters of GA operators influence optimisation collectively. Finally using the best parameter set, strengths and weaknesses of Sl-Opt were evaluated using two case studies: a hospital layout problem with 31 SUs and a problem with 10 non-rectangular SUs. Findings revealed that using the selected GA parameters Sl-Opt can successfully solve small scale problems of about less than 10 SUs. For larger prob- lems, the parameters need to be altered. Case studies also revealed that the system is capable of solving problems with non-rectangular SUs with varied 0rientations. Sl-Opt appear to have potential as a building layout decision support tool, and in addition, integration of other aspects such as energy efficiency and cost is possible.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Automated space layout planning for environmental sustainability

There is a growing global interest in low/zero carbon buildings in response to the increased CO2 in the atmosphere, nearly half of which comes from building energy consumption. Buildings are built for a considerably longer lifespan and enhancing energy efficiency in buildings can play a significant role in reducing CO2 emissions. Energy efficiency features need to be incorporated at the earliest, as alterations to the design at latter stages may prove to be difficult and sometimes expensive. Building design is concerned with satisfying various objectives (e.g. cost, efficiency of a space layout, energy consumption), which are sometimes in conflict with each other. Performance of various indicators, therefore, needs to be assessed as a whole rather than in isolation. Space layout planning is considered as the starting point of building design. Most performance indicators; i.e. cost, energy efficiency, etc. are closely linked with the layout. Researchers have attempted at automating space layout planning since the 1960s with a view to effectively search the solution space. Diverse approaches are adopted in space layout planning that ranges from the analysis of spatial proximity to the application of ‘space syntax’ theory. Developments in whole building energy simulation and integration of simulation in the design process imply that the search for optimum space layout could be better guided by incorporating detailed-based simulation as response generators as opposed to the ones with a simplified representation of the problem domain. This paper describes a framework for sustainable space layout planning that uses evolutionary computation methods to search the solution space. Whole building simulation programs are used as response generators to guide the search for energy efficient layouts. The integrated approach enables the consideration of energy consumption, in addition to the geometry and topology, for decision making during space layout planning

Experimental evidence supports mantle partial melting in the asthenosphere

The low-velocity zone (LVZ) is a persistent seismic feature in a broad range of geological contexts. It coincides in depth with the asthenosphere, a mantle region of lowered viscosity that may be essential to enabling plate motions. The LVZ has been proposed to originate from either partial melting or a change in the rheological properties of solid mantle minerals. The two scenarios imply drastically distinct physical and geochemical states, leading to fundamentally different conclusions on the dynamics of plate tectonics. We report in situ ultrasonic velocity measurements on a series of partially molten samples, composed of mixtures of olivine plus 0.1 to 4.0 volume % of basalt, under conditions relevant to the LVZ. Our measurements provide direct compressional (VP) and shear (VS) wave velocities and constrain attenuation as a function of melt fraction. Mantle partial melting appears to be a viable origin for the LVZ, for melt fractions as low as ∼0.2%. In contrast, the presence of volatile elements appears necessary to explaining the extremely high VP/VS values observed in some local areas. The presence of melt in LVZ could play a major role in the dynamics of plate tectonics, favoring the decoupling of the plate relative to the asthenosphere

Electronic Band Transitions in γ-Ge3N4

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Support from Estonian Research Council grant PUT PRG 619 is gratefully acknowledged. The multi-anvil experiments at LMV were supported by the French Government Laboratory of Excellence initiative no ANR-10-LABX-0006, the Région Auvergne and the European Regional Development Fund (ClerVolc Contribution Number 478).Electronic band structure in germanium nitride having spinel structure, γ-Ge3N4, was examined using two spectroscopic techniques, cathodoluminescence and synchrotron-based photoluminescence. The sample purity was confirmed by x-ray diffraction and Raman analyses. The spectroscopic measurements provided first experimental evidence of a large free exciton binding energy De≈0.30 eV and direct interband transitions in this material. The band gap energy Eg = 3.65 ± 0.05 eV measured with a higher precision was in agreement with that previously obtained via XES/XANES method. The screened hybrid functional Heyd–Scuseria–Ernzerhof (HSE06) calculations of the electronic structure supported the experimental results. Based on the experimental data and theoretical calculations, the limiting efficiency of the excitation conversion to light was estimated and compared with that of w-GaN, which is the basic material of commercial light emitting diodes. The high conversion efficiency, very high hardness and rigidity combined with a thermal stability in air up to ~ 700 °C reveal the potential of γ-Ge3N4 for robust and efficient photonic emitters. © 2021, The Korean Institute of Metals and Materials. Published under the CC BY license.Euratom research and training programme 2014-2018 633053; Eesti Teadusagentuur ANR-10-LABX-0006, PUT PRG 619; ERDF; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2

Effect of oxygen fugacity on the storage of water in wadsleyite and olivine in H and H–C fluids and implications for melting atop the transition zone

This study aims to experimentally constrain the water storage capacities of olivine and wadsleyite at a depth near 410 km (12–14 GPa) under water-saturated conditions, as a function of temperature, oxygen fugacity, and the presence of carbon (molar H / C of 2). Experiments have been conducted in the multi-anvil press, with sealed double capsules to preserve fluids, at 1200 to 1400 ∘C and three different oxygen fugacities fixed at the rhenium–rhenium oxide buffer (RRO), nickel–nickel oxide buffer (NNO), and iron-wüstite (IW) for oxidizing, intermediate, and reducing conditions, respectively. The water contents of minerals were measured by Raman spectroscopy that allows a very small beam size to be used and were cross-checked on a few samples with NanoSIMS analyses. We observe an effect, although slight, of fO2 on the water storage capacity of both wadsleyite and olivine and also on their solidus temperatures. At 1200 ∘C, the storage capacity of the nominally anhydrous minerals (NAMS) increases with increasing oxygen fugacity (from the IW to the RRO buffer) from 1 wt % to 1.5 wt % H2O in wadsleyite and from 0.1 wt % to 0.2 wt % in olivine, owing to the increase in H2O / H2 speciation in the fluid, whereas at 1400 ∘C the storage capacity decreases from 1 wt % to 0.75 wt % H2O in wadsleyite and down to 0.03 wt % for olivine. At high temperature, the water storage capacity is lowered due to melting, and the more oxidized the conditions are the more the solidus is depressed. Still, at 1400 ∘C and IW, wadsleyite can store substantial amounts of water: 0.8 wt % to 1 wt % H2O. The effect of carbon is to decrease water storage capacity in both wadsleyite and olivine by an average factor 2 at 1300–1400 ∘C. The trends in water storage as a function of fO2 and C presence are confirmed by NanoSIMS measurements. The solidus at IW without C is located between 1300 and 1400 ∘C in the wadsleyite stability field and drops to temperatures below 1300 ∘C in the olivine stability field. With the addition of C, the solidus is found between 1200 and 1300 ∘C in both olivine and wadsleyite stability fields.</p

Melting phase relations in the systems Mg2SiO4-H2O and MgSiO3-H2O and the formation of hydrous melts in the upper mantle

High-pressure and high-temperature melting experiments were conducted in the systems Mg2SiO4–H2O and MgSiO3–H2O at 6 and 13 GPa and between 1150 and 1900 °C in order to investigate the effect of H2O on melting relations of forsterite and enstatite. The liquidus curves in both binary systems were constrained and the experimental results were interpreted using a thermodynamic model based on the homogeneous melt speciation equilibrium, H2O + O2− = 2OH−, where water in the melt is present as both molecular H2O and OH− groups bonded to silicate polyhedra. The liquidus depression as a function of melt H2O concentration is predicted using a cryoscopic equation with the experimental data being reproduced by adjusting the water speciation equilibrium constant. Application of this model reveals that in hydrous MgSiO3 melts at 6 and 13 GPa and in hydrous Mg2SiO4 melts at 6 GPa, water mainly dissociates into OH− groups in the melt structure. A temperature dependent equilibrium constant is necessary to reproduce the data, however, implying that molecular H2O becomes more important in the melt with decreasing temperature. The data for hydrous forsterite melting at 13 GPa are inconclusive due to uncertainties in the anhydrous melting temperature at these conditions. When applied to results on natural peridotite melt systems at similar conditions, the same model infers the presence mainly of molecular H2O, implying a significant difference in physicochemical behaviour between simple and complex hydrous melt systems. As pressures increase along a typical adiabat towards the base of the upper mantle, both simple and complex melting results imply that a hydrous melt fraction would decrease, given a fixed mantle H2O content. Consequently, the effect of pressure on the depression of melting due to H2O could not cause an increase in the proportion, and hence seismic visibility, of melts towards the base of the upper mantle

Design optimisation using convex programming: Towards waste-efficient building designs

© 2019 The Authors A non-modular building layout is amongst the leading sources of offcut waste, resulting from a substantial amount of onsite cutting and fitting of bricks, blocks, plasterboard, and tiles. The field of design for dimensional coordination is concerned with finding an optimal configuration for non-overlapping spaces in the layout to reduce materials waste. In this article, we propose a convex optimisation-based algorithm for finding alternative floor layouts to enforce the design for dimensional coordination. At the crux of the proposed algorithm lies two mathematical models. The first is the convex relaxation model that establishes the topology of spaces within the layout through relative positioning constraints. We employed acyclic graphs to generate a minimal set of relative positioning constraints to model the problem. The second model optimises the geometry of spaces based on the modular size. The algorithm exploits aspect ratio constraints to restrict the generation of alternate layouts with huge variations. The algorithm is implemented in the BIMWaste tool for automating the design exploration process. BIMWaste is capable of investigating the degree to which designers consider dimensional coordination. We tested the algorithm over 10 completed building projects to report its suitability and accuracy. The algorithm generates competitive floor layouts for the same client intent that are likely to be tidier and more modular. More importantly, those floor layouts have improved waste performance (i.e., 8.75% less waste) due to a reduced tendency for material cutting and fitting. This study, for the first time, used convex programming for the design optimisation with a focus to reduce construction waste