Building Platform Research Articles

Connected backyard gardening as a platform for suburban community building in Adelaide, Australia

ABSTRACT In a connected backyard gardening scheme, the backyards of neighboring houses are connected through mutually accessible gates so that the individual households can benefit from the sharing of resources, and develop social links with neighbors. This study highlights the significance of connected backyard gardening in terms of community building, based on interviews with a group of five households and a group of three households from two suburban streets in Adelaide, Australia. The study has found that these connected backyard gardens are a new form of intentional communities. They have demonstrated it is possible to carry out a sharing economy, a circular economy, and a platform economy in a small scale yet collective and innovative manner. The spread of connected backyard gardening in Adelaide is being challenged by land-subdivision pressure favoring urban infill. The study suggests the social benefits of collective residential gardening should be factored into city planning.

The effect of build direction and geometric optimization in laser powder bed fusion of Inconel 718 structures with internal channels

A laser powder bed fusion (LPBF) strategy was developed for manufacturing small channels with high dimensional accuracy in Inconel 718 structures. Particular attention was paid to surface characteristics such as equivalent diameter and shape factor. The inherent surface quality of external surfaces was optimized by a systematic variation of the LPBF contour parameters as well as the channel cross-section. The mean arithmetic roughness Sa was analysed for upskin, vertical and downskin surfaces with respect to the build platform. Simultaneously, the effect of the build direction on the quality of internal free-shaped surfaces was investigated on channels with diameters from 500 to 1000 µm and build orientations from the horizontal (0°) to vertical (90°). A significant improvement in dimensional accuracy was achieved by using an optimized droplet-shaped cross-section that is scaled as a function with the build inclination. An angular analysis of the surface roughness in different regions of the channels confirms that this modified cross-section reduces the fraction of channel regions that show a particularly high surface roughness due to inward melting. In combination with an optimized contour processing strategy, the modified channel resulted in the best properties for inclinations below 45°. The shape factor increased from 0.4 to almost 0.9, i.e., close to the ideally round shape.

Volatile fatty acid platform - a cornerstone for the circular bioeconomy.

Annually, the EU produces more than 100 million tonnes of urban biowaste, which is largely under-valorized and in some cases even still landfilled without any energy or material recovery. If Europe wants to be ready for the future, it will need to make better use of this large biomass potential within a circular economy approach. The research project funded by the European Commission under the Horizon 2020 programme entitled 'VOLATILE-Biowaste derived volatile fatty acid platform for biopolymers, bioactive compounds and chemical building blocks' aimed to produce volatile fatty acids (VFAs) from biowaste for reprocessing into products, materials or substances to close the material loop. During the project, the partners were able to obtain average volatile fatty acid yields of 627g COD/kg organic matter (OM) for food waste, 448g COD/kg OM for separately collected vegetable, garden and fruit waste (VGF) and 384g COD/kg OM for the organic fraction of municipal solid waste (OF-MSW) at concentrations ranging from 12 to 48g/L, 6 to 40g/L and 13 to 26g/L, respectively. A membrane filtration cascade consisting of micro-, ultra- and nano-filtration followed by reverse osmosis was identified as a feasible way to purify and concentrate the VFA effluent, making them a suitable carbon source for further fermentation processes. Besides technical optimization, socio-economic and legal aspects associated with this platform technology were also studied and show that although this technology is still in development, it is providing an answer to changing societal and market expectations both regarding organic waste treatment and bio-based production strategies. Based on the current technological, economic and market evolutions, it is expected that the VFAP will play an important role in organic waste treatment in the coming years.

Mechanical and morphological properties of additively manufactured SS316L and Ti6Al4V micro-struts as a function of build angle.

Additive manufacturing methods such as laser powder bed fusion (PBF) can produce micro-lattice structures which consist of ‘micro-struts’, which have properties that differ from the bulk metal and that can vary depending on the orientation of the strut to the build direction (the strut build angle). Characterizing these mechanical and morphological changes would help explain macro-scale lattice behavior. Individual stainless steel (SS316L) and titanium alloy (Ti6Al4V) laser PBF struts were built at 20°, 40°, 70° and 90° to the build platform, with 3 designed diameters and tested in uniaxial tension (n = 5). Micro-CT was used to quantify changes in surface roughness, eccentricity and cross-section. Average elastic modulus was 61.5 GPa and 37.5 GPa for SS316L and Ti6Al4V respectively, less than the bulk material. Yield strength was uniform over build angle for SS316L, but for Ti6Al4V varied from 40% to 98% of the bulk value from 20° to 90° build angles. All lower angle struts had worse morphology, with higher roughness and less circular cross-sections. These data should help inform micro-lattice design, especially in safety critical applications where lower mechanical performance must be compensated for.

The C-BIG Repository: an Institution-Level Open Science Platform

In January 2016, the Montreal Neurological Institute-Hospital (The Neuro) declared itself an Open Science organization. This vision extends beyond efforts by individual scientists seeking to release individual datasets, software tools, or building platforms that provide for the free dissemination of such information. It involves multiple stakeholders and an infrastructure that considers governance, ethics, computational resourcing, physical design, workflows, training, education, and intra-institutional reporting structures. The C-BIG repository was built in response as The Neuro’s institutional biospecimen and clinical data repository, and collects biospecimens as well as clinical, imaging, and genetic data from patients with neurological disease and healthy controls. It is aimed at helping scientific investigators, in both academia and industry, advance our understanding of neurological diseases and accelerate the development of treatments. As many neurological diseases are quite rare, they present several challenges to researchers due to their small patient populations. Overcoming these challenges required the aggregation of datasets from various projects and locations. The C-BIG repository achieves this goal and stands as a scalable working model for institutions to collect, track, curate, archive, and disseminate multimodal data from patients. In November 2020, a Registered Access layer was made available to the wider research community at https://cbigr-open.loris.ca, and in May 2021 fully open data will be released to complement the Registered Access data. This article outlines many of the aspects of The Neuro’s transition to Open Science by describing the data to be released, C-BIG’s full capabilities, and the design aspects that were implemented for effective data sharing.

Analysis performance of wavelet OFDM in mobility platforms

Wavelet orthogonal frequency division multiplexing (OFDM) is one of the medium access techniques recommended by the IEEE 1901 working group for broadband communications over electrical networks, and is under consideration for IoT applications. This standard provides a flexible architecture supporting integrated access, smart grid, building, in-home, and mobility platform (vehicle) applications. Wavelet OFDM is a filter bank multicarrier system based on the extended lapped transform, in which the transmitting and receiving filters are obtained from a waveform provided by the standard. In this paper, we explore system performance when other waveforms are employed, studying the trade-off between stopband attenuation and transition band width. Furthermore, an alternative and more efficient way of obtaining the theoretical expressions of the achievable data rate is shown, assuming realistic power line communication noise other than additive white Gaussian noise. To demonstrate the capabilities of wavelet OFDM, the results of simulation of the symbol error rate and the data rate in several systems in platform scenarios (in-vehicle and in-aircraft) are shown.

CO2 laser polishing of laser-powder bed fusion produced AlSi10Mg parts

Poor surface quality represents an important issue that needs improvement for metal Additively Manufactured parts. Both short or long wavelength lasers have been applied for surface polishing in order to improve the surface finish. In this work, the possible use of a CO 2 laser for the surface polishing of AlSi10Mg parts made by Laser-based Powder Bed Fusion (L-PBF) was explored. The high surface roughness in the as-built condition can lead to increased laser energy absorption. In order to assess the effects of the main laser-related process parameters, the experiments were carried out on L-PBF samples built vertically with respect to the build platform. Their effect on the surface were evaluated by means of the surface arithmetical mean height (S a ), surface skewness (S sk ) and primary profile root mean square slope (P dq ), obtained via confocal microscopy . Microstructure evolution was also investigated by means of SEM and EDS analysis. The results showed a large reduction in surface roughness, ranging from the 67% to the 85% of the starting value. Microstructure of the re-molten layer revealed an increased grain size and an increased Si content that led to an overall hardness increase from 85 to 121 HV. • A CO 2 laser was used to perform surface re-melting of AlSi10Mg L-PBF samples. • The surface roughness (S a ) was reduced up to the 85%. • Surface symmetry, analyzed by means of areal skewness (S sk ), was improved. • Profile root mean square slope (P dq ) was also evaluated and reduced up to the 90%. • Vickers microhardness increased up to the 30% in the polished area.

Accurate Bracket Placement with an Indirect Bonding Method Using Digitally Designed Transfer Models Printed in Different Orientations-An In Vitro Study.

Objective: A digital workflow opens up new possibilities for the indirect bonding (IDB) of brackets. We tested if the printing orientation for bracket transfer models on the build platform of a 3D printer influences the accuracy of the following IDB method. We also evaluated the clinical acceptability of the IDB method combining digitally planned and printed transfer models with the conventional fabrication of pressure-molded transfer trays. Materials and Methods: In total, 27 digitally planned bracket transfer models were printed with both 15° and 75° angulation from horizontal plane on the build platform of a digital light processing (DLP) printer. Brackets were temporarily bonded to the transfer models and pressure-molded trays were produced on them. IDB was then performed using the trays on the respective plaster models. The plaster models were scanned with an optical scanner. Digitally planned pre-bonding and scanned post-bonding bracket positions were superimposed with a software and resulted in three linear and three angular deviations per bracket. Results: No statistically significant differences of the transfer accuracy of printed transfer models angulated 15° or 75° on the 3D printer build platform were found. About 97% of the linear and 82% of the angular deviations were within the clinically acceptable range of ±0.2 mm and ±1°, respectively. The highest inaccuracies in the linear dimension occurred in the vertical towards the gingival direction and in the angular dimension in palatal crown torque. Conclusion: For the IDB method used, the printing orientation on the build platform did not have a significant impact on the transfer accuracy.

Analysis of constraints on data management of intelligent platform for smart building in the era of big data

With the rapid development of science and technology in China, data has become the core of various fields and industries. The construction industry is the first to bear the brunt. The merits and demerits of data management can directly determine whether smart buildings are worthy of the term “smart”. However, at present, the management level of most intelligent platform data of smart buildings is low, which cannot well adapt to and meet the development needs of smart buildings. Therefore, in view of the problems existing in the data management of the intelligent platform of the existing smart building in the era of big data, this paper conducts in-depth research and exploration, and points out the main restraining factors of the data management of the intelligent platform of the smart building. This paper expounds how to achieve more fine, safe and intelligent management of the data of intelligent platform of smart buildings in the era of big data.

Real-time monitoring of volatiles and particles emitted from thermoplastic filaments during 3D printing

The proliferation of consumer-grade three-dimensional (3D) printers using fused deposition, also known as fused filament fabrication, has given rise to concerns over the exposure of users to potentially harmful substances. Thermoplastic filaments made of different polymers are extruded through a heated printer nozzle and deposited layer by layer on a build platform to form the printed object. This process leads to the emission of both particles and gases, in particular volatile organic compounds (VOCs). While the emission of airborne particulate matter during 3D-printing has been relatively well researched [1], this is not the case with the monitoring of the associated emission of VOCs, and so we are far from understanding the emission profile of 3D-printers as a whole. The main reason for that is the difficulty with sampling the emitted volatiles with sufficient time resolution to investigate e.g. the effect of rapid heating of the nozzle, and so the available data mostly describes either the total emission of particular VOCs during printing, or the time-resolved emission of total VOCs, without the determination of particular compounds [2,3]. In order to bridge this gap, we have previously demonstrated that proton transfer reaction mass spectrometry (PTR-MS) can be used to monitor the emission of volatiles during 3D-printing in real-time, both qualitatively and quantitatively [4]. Here, we propose to combine this approach with the concurrent real-time measurement of the corresponding emission of particles to obtain a more detailed understanding of the profile of pollutants generated during 3D-printing and the factors which determine this process.

Three-Dimensional Printing of Self-Assembled Dipeptides.

Peptide-based materials are emerging as smart building blocks for nanobiodevices due to the programmability of their properties via the molecular constituents or arrangements. Many clever molecular self-assembly approaches have been devised to produce peptide crystalline structures. However, their freeform shaping remains a challenge due to the intrinsic self-assembly nature. Here, we report the fabrication of freeform, crystalline diphenylalanine (FF) peptide structures by combining meniscus-guided 3D printing with molecular self-assembly. Self-assembly in 3D-printed FF arises from mild thermal activation under precise temperature control of the build platform. After thorough characterizations, we demonstrate layer-by-layer, crystalline 3D printing with a high spatial resolution of 2 μm laterally and 200 nm vertically. The 3D-printed FF exhibits piezoelectricity originating from its crystalline character, showing the potential to become a key constituent for bioelectronic devices. We expect this technique to open up the possibility to create functional devices based on self-assembled organic materials without design restrictions.

Roughness and Near-Surface Porosity of Unsupported Overhangs Produced by High-Speed Laser Powder Bed Fusion.

Laser powder bed fusion (LPBF) is a promising technology that requires further work to improve productivity to be adopted more widely. One possible approach is to increase the laser power and scan speed. A customized high-speed and high-power LPBF system has been developed for this purpose. The current study investigated the surface roughness and near-surface porosity as a result of unsupported overhangs at varying inclination angles and orientations during the manufacturing of Ti6Al4V parts with this custom high-speed and high-power LPBF system. It is known that surface roughness and porosity are among the main drawbacks for parts manufactured by LPBF, and that supports are required for overhang regions with low inclination angles relative to the powder bed, typically in commercial LPBF systems requiring supports for regions with inclination angles less than 45°. However, the appropriate inclination angles for this custom system with high power and speed requires investigation. In this article, a simple benchmark test artefact with different inclination angles was manufactured in different orientations on the build platform and characterized by X-ray tomography, touch probe roughness meter, optical microscopy, and scanning electron microscopy. The analysis of surface roughness and near-surface porosity at upskin and downskin regions was performed as a function of inclination angle. The results indicate that the high-speed LPBF process produces relatively high roughness in all cases, with different porosity distributions at upskin and downskin areas. Both roughness and porosity vary as a function of inclination angle. Significant warping was observed, depending on build orientation relative to laser scanning direction. These are the first reported results of the detailed surface roughness and porosity characterization of part quality from such a high-speed, high-power LPBF process.

Knowledge Graph Construction for Electric Power Science and Technology Achievements

The management of power technology requires great effort and cost due to its wide coverage and complex data types. However, under the current technical background of deepening informatization degree, negative effects such as large information redundancy and ambiguous information makes it facing greater challenges. Based on this, this paper proposes to realize the effective management of electric power science and technology information by means of knowledge graph. We use the data of electric power science and technology achievements from 2005 to 2018 to build the knowledge graph through the knowledge graph building platform, so as to provide effective management methods for the management of electric power sci-tech achievements

Rapid development of fast and flexible environmental models: the Mobius framework v1.0

Abstract. The Mobius model building system is a new open-source framework for building fast and flexible environmental models. Mobius makes it possible for researchers with limited programming experience to build performant models with potentially complicated structures. Mobius models can be easily interacted with through the MobiView graphical user interface and through the Python programming language. Mobius was initially developed to support catchment-scale hydrology and water-quality modelling but can be used to represent any system of hierarchically structured ordinary differential equations, such as population dynamics or toxicological models. Here, we demonstrate how Mobius can be used to quickly prototype several different model structures for a dissolved organic carbon catchment model and use built-in auto-calibration and statistical uncertainty analysis tools to help decide on the best model structures. Overall, we hope the modular model building platform offered by Mobius will provide a step forward for environmental modelling, providing an alternative to the “one size fits all” modelling paradigm. By making it easier to explore a broader range of model structures and parameterisations, users are encouraged to build more appropriate models, and in turn this improves process understanding and allows for more robust modelling in support of decision making.

TBM-spoil characterization and utilization at the Follo Line project

The potential use of surplus materials commonly considered as waste has been investigated by the project “Geomaterials in the Circular Economy” (GEOreCIRC). TBM spoil is one of the materials which were assessed, based on data from the Follo Line tunnel project in Oslo, Norway. For this tunnel, four TBMs were used simultaneously and the tunnel generated almost 9 million metric tonnes of spoil. The excavated TBM spoil was used to establish a building platform for a new district in the Oslo municipality, by filling a 30 m deep valley. An extensive campaign of laboratory testing, field measurements and monitoring was conducted for the deposit. The geotechnical properties, such as grain size distribution, grain shape, brittleness, density, permeability and friction angle were determined. The optimal water content for compaction and maximum dry density were determined using the Standard Proctor test. Field measurements included plate load tests and nuclear density gauge (Troxler), with several measurements for each layer of the deposit. In addition, the spoil was analysed for a wide range of possible contaminants associated with natural rock minerals and machinery used in the tunnelling process. The results show that the level of contamination is low, and related to background levels from the bedrock itself, with levels below specified threshold values for contaminated soil according to Norwegian regulations.

The Influence of Environment on the Settlement of Historic Buildings in China

Chinese ancient wooden buildings prefer fronting water and with hills on the back. Therefore, some ancient buildings were built on the bedrock of the mountain. The uneven height of the building platform from the bedrock causes the uneven settlement of the foundation. Due to the disturbance of groundwater, the uneven settlement of the building foundation will also change due to the groundwater. This paper takes the Song Dynasty Jinci Goddess Mother Hall as an example to compare the settlement of the original foundation and the settlement of the repaired foundation. Summarize the effect of groundwater and the bedrock location of the settlement of ancient building platforms under different strengthening methods. The Flac-3D simulation software was used to simulate the foundation and load of the building. The numerical simulation results show that the settlement value after reparation is reduced by 84% compared with that before. The values of the settlement trend are similar to actual data, which has to guide significance for the prediction of building settlement and the protection of the building. Authors can provide references for future protection and the foundation reinforcement of similar buildings by comparing the foundation reinforcement methods by actual measurement and numerical simulation.

THE MAUSOLEUM ARCHITECTURAL PROJECT: REINTERPRETING PALENQUE'S TEMPLE OF THE INSCRIPTIONS THROUGH 3D DATA-DRIVEN ARCHITECTURAL ANALYSIS

AbstractThe Temple of the Inscriptions at Palenque, Mexico, is an outstanding example of Classic Maya architecture erected in the seventh century as the funerary building for ruler K'inich Janab Pakal. For decades, scholars have speculated on its construction sequence and the potential existence of hidden rooms on either side of Pakal's mortuary chamber. This article aims to advance understanding of the Temple's architectural context in light of new 3D data. After reviewing the application of drone-based photogrammetry and terrestrial Light Detection and Ranging in the Maya area, we argue that these techniques are capable of enhancing the architectural analysis of the Temple of the Inscriptions and showing that this structure was part of a larger architectural project, encompassing the adjacent Temple XIII, and the connecting stepped building platform. Our findings demonstrate that the basal platforms for the Temple of the Inscriptions and Temple XIII were erected contemporaneously and that the design of their mortuary chambers follows a tripartite layout we identified in Palenque's elite funerary architecture and associated mortuary practices. We conclude that these three buildings were part of a mausoleum architectural project, the construction of which was initiated by Pakal to reshape Palenque's site-core and enshrine the ruling family's power and ancestors.

Production and characterization of Ti6Al4V/CaP nanocomposite powder for powder-based additive manufacturing systems

Ti64/CaP nanocomposite powder was fabricated and characterized for use in powder-bed 3D printing. The microstructure and phase composition, morphology, particle size distribution, sphericity, flow behavior and dispersion of the as-fabricated particles on the building plate of the 3D printer were investigated. The results confirmed a uniform distribution of nanostructured calcium phosphate particles on the surface of primary Ti64 ones. Calcium phosphate appears as an octa-calcium phosphate phase. The morphology of the particles was shown as spherical, and their sphericity was better than the as-received Ti64 particles. The particle size distribution of nanocomposite powder indicated a smaller amount than the as-received Ti64 particles. Additionally, the flow behavior was improved compared to the as-received Ti64 and delivered an optimal dispersion on the building platform. Ultimately, Ti64/CaP nanocomposite powder has a very homogeneous and uniform microstructure and bears a proper flow behavior for use in powder-bed additive manufacturing machines.

ВИБІР ПАРАМЕТРІВ ПРОЦЕСУ СЕЛЕКТИВНОГО ЛАЗЕ-РНОГО ПЛАВЛЕННЯ ДЛЯ МЕТАЛЕВИХ ПОРОШКІВ

The article deals with the issues of determining the optimal parameters of the selective laser melting (SLM) process in order to develop a technology for manufacturing aircraft structural elements from titanium alloys. This literature review notes the advantages of titanium alloys, which have higher specific strength and corrosion resistance compared to most steels and aluminum alloys. It is determined that traditional methods of forming titanium parts lead to a large amount of material waste, high production costs and long production times. It is noted that the SLM technology makes it possible to create parts of titanium alloys with complex geometry. It is also emphasized that the titanium glory Ti-6Al-4V is the most popular titanium alloy used in aircraft construction. This paper presents a description of the SLM process and a list of parameters that affect design and final material properties. Attention is drawn to the main parameters of SLM: energy density, process temperature (temperature of the building platform), environmental conditions, material properties and scanning strategy. The influence of the above parameters of the SLM process on product quality and production time is shown. Finding the optimal values for the SLM process parameters is an important step in creating a part that is manufactured to obtain priority mechanical properties. The need is stressed to employed a protective atmosphere during the process is emphasized, the use of internal gases (nitrogen, argon and helium) to prevent oxidation, significantly affects the process, the final mechanical properties and microstructure of the parts produced. It is shown that for the production of high-quality products, it is important that the metal powder has a spherical grain shape and a size not exceeding the thickness of one applied layer. The build chamber temperature should be varied depending on the desired mechanical properties of the final product. Variable process parameters (scanning strategy, laser parameters) affect the thermal balance, productivity, geometric accuracy of porosity, which affects the mechanical properties and microstructure. This analysis of foreign experience and future research will further improve the technology for the production of aircraft structural elements.

Impact of high temperature stress relieving on final properties of Inconel 718 processed by laser powder bed fusion

Abstract During manufacture of Inconel 718 (IN718) parts with complex geometry and high dimensional accuracy by laser powder bed fusion (LPBF), effective stress relieving is required before cutting off the parts from the build platform, in order to prevent distortion. The residual stress can be removed completely only by full recrystallization of structure, induced by annealing at the temperature close to that used in hot isostatic pressing (HIP). This work was aimed at investigating the effect of stress-relieving at 1150 °C for 6 h on properties of LPBF-ed IN718, obtained after each of successive thermal processing steps: optional HIP, solution annealing and double aging, in relation to analogous research performed with use of the thermal processing parameters recommended by ASTM standards. In addition, the effect of heating and cooling rates during individual heat-treatment steps on dissolution and precipitation of secondary phases was investigated. It was shown that an advantage of stress relieving at 1150 °C in comparison to the standard annealing at 1065 °C is higher effectiveness of stress elimination, higher resistance to liquid-film formation during heating-up, lack of delta phase, significantly higher elongation (48%) and area reduction (30%) of IN718 in final (without HIP) aged condition. Although the high-temperature stress relieving and HIP treatments resulted in coarse-grained microstructures, the tensile strength values determined at room and elevated temperatures (425 °C and 650 °C) were higher than the nominal values of wrought IN718 with similar grain size and much higher than those of cast and HIP-ed IN718.