1,036 research outputs found
Conclusion: On the Way to New Species of Lightweight Energy-Conscious Membrane Architecture
With this book we wanted to underline that the “species jump” of textile archi-tecture and membrane architecture is underway, driven forward by the technical innovations that have taken place in the chemistry of materials on the one hand and by automation and electronic miniaturization on the other
Design-driven Uniaxial and Biaxial Tensile Testing of Knitted Fabrics Applied to Construction
Knitted fabrics are rarely subjected to tensile stress tests in the field of architectural construction
materials, mostly due to their common use as drapery. However, recent non-standard applications
of tensioned knitted textiles to hybrid lightweight constructions call for the assessment of their
mechanical behavior. In the light of the absence of specific testing methodologies regarding
knitted fabrics in the field of construction, this study aims at investigating customized testing
techniques that target design requisites, as well as extending previous groundwork on plain weftknitted
textiles to tuck-loop knit structures. Fabrics with a piquet Lacoste loop structure are tested
uniaxially and biaxially in order to estimate the feasibility of a relatively large-scale project. The
challenging task consists of stretching the limited production width in weft direction to the
extended dimensions of the tensile architectural project. Hence the study focuses on elongation
limits and especially on the maximum elongation that allows elastic deformation. Extracted
empirical data are expressed in the form of stress/strain curves that enable an appropriate
understanding of the textiles’ mechanical behavior. This inquiry points out the extent to which knit
pattern favors directional elongation in warp as opposed to weft or vice-versa. In addition, it
addresses the mechanical performance of knitted textiles by means of a strategic customization of
tensile tests that can make them better at informing the design process and feasibility assessment
Experimental Validation of Optical Simulation for Complex Building Integrated Photovoltaic System.
Simulation of BIPV system performance is usually based on a Plane-Of-Array method, adopted from classical PV plant systems, to estimate power generation. This methods is very limited for simulating facades in complex urban environments, such as dense urban areas, as it uses simplified near-field shading to estimate system losses. Furthermore, this approach accounts only for PV electricity yield generation, while neglecting other architectural criteria like daylighting, especially important in case of semi transparent PV facade. For the purposes of complex BIPV facades, other methods, such as ray tracing, are more preferable. Therefore, this research aims to estimate capabilities and accuracy of RADIANCE ray tracing engine to calculate daylighting and irradiance on PV surface. Validation procedure has been carried out for complex BIPV façade module, composed of complex profiled glass tile and semi-transparent Dye-Sensitized Solar Cells. Results showed reasonably good agreement between simulation and experimental measurements, which proves that method is capable for being used for the general purposes of complex BIPV systems
Quantum Degenerate Systems
Degenerate dynamical systems are characterized by symplectic structures whose
rank is not constant throughout phase space. Their phase spaces are divided
into causally disconnected, nonoverlapping regions such that there are no
classical orbits connecting two different regions. Here the question of whether
this classical disconnectedness survives quantization is addressed. Our
conclusion is that in irreducible degenerate systems --in which the degeneracy
cannot be eliminated by redefining variables in the action--, the
disconnectedness is maintained in the quantum theory: there is no quantum
tunnelling across degeneracy surfaces. This shows that the degeneracy surfaces
are boundaries separating distinct physical systems, not only classically, but
in the quantum realm as well. The relevance of this feature for gravitation and
Chern-Simons theories in higher dimensions cannot be overstated.Comment: 18 pages, no figure
DESIGN TOOLS FOR INFLATABLE STRUCTURES
This paper shows different tools and approaches that can be useful for the definition of the design of pneumatic structures. Some of these tools have been applied for the design of a Tensairity® hull
Il monitoraggio delle aree archeologiche per l'ottimizzazione del progetto delle coperture
The aim to keep the original architectures and decoration in their excavation site, that has been emerging in the last years, requires to protect them by temporary or definitive shelters. Soprintendenza per i Beni Archeologici of Cagliari and Oristano promoted and started monitoring four shelters already existing on the archaeological areas of these provinces, with the aim to check the effectiveness in the local environment, and to plan their improvement or/and new structures. Politecnico di Milano collaborated at the research by monitoring the environment and remains conditions, especially underneath the shelters, modelling the effects of the existing shelters and planning new solutions. In San Cromazio (Villaspeciosa), monitoring the new definitive shelter allowed the researchers to discover the critical points and to find out their improvement. In Su Monte (Sorradile), monitoring allowed the researchers to define the expected performances of the new shelter. In San Saturnino (Cagliari) monitoring and numerical analysis was applied to 2D and 3D models for improving the ventilation of the volume underneath the new shelter. In Nora (Pula) the results of monitoring and the innovative approach of design served to check the performances of the present temporary shelters. Nora approach shows how to overcome the limits of current protective systems, combining the requirements for preservation with new issues as feasibility of technical textiles, low maintenance and easy deconstruction to allow the reuse and adaptability of shelters in different locations and seasons. The ultimate goal was to renovate the design process by covering archaeological sites in a more environmentally conscious way and without the least destruction of the site
Optical Properties of a \theta-Vacuum
Chern-Simons (CS) forms generalize the minimal coupling between gauge
potentials and point charges, to sources represented by charged extended
objects (branes). The simplest example of such a CS-brane coupling is a domain
wall coupled to the electromagnetic CS three-form. This describes a
topologically charged interface where the CS form AdA is supported, separating
two three-dimensional spatial regions in 3+1 spacetime. Electrodynamics at
either side of the brane is described by the same Maxwell's equations, but
those two regions have different vacua, characterized by a different value of
the \theta-parameter multiplying the Pontryagin form F ^ F. The \theta-term is
the abelian version of the concept introduced by 't Hooft for the resolution of
the U(1) problem in QCD. We point out that CS-generalized classical
electrodynamics shows new phenomena when two neighboring regions with different
\theta-vacua are present. These topological effects result from surface effects
induced by the boundary and we explore the consequences of such boundary
effects for the propagation of the electromagnetic field in Maxwell theory.
Several features, including optical and electrostatic/magnetostatic responses,
which may be observable in condensed matter systems, like topological
insulators, are discussed.Comment: 11 pages, no figure
Numerical investigation of 48 V electrification potential in terms of fuel economy and vehicle performance for a lambda-1 gasoline passenger car
Real Driving Emissions (RDE) regulations require the adoption of stoichiometric operation across the entire engine map for downsized turbocharged gasoline engines, which have been so far generally exploiting spark timing retard and mixture enrichment for knock mitigation. However, stoichiometric operation has a detrimental effect on engine and vehicle performances if no countermeasures are taken, such as alternative approaches for knock mitigation, as the exploitation of Miller cycle and/or powertrain electrification to improve vehicle acceleration performance. This research activity aims, therefore, to assess the potential of 48 V electrification and of the adoption of Miller cycle for a downsized and stoichiometric turbocharged gasoline engine. An integrated vehicle and powertrain model was developed for a reference passenger car, equipped with a EU5 gasoline turbocharged engine. Afterwards, two different 48 V electrified powertrain concepts, one featuring a Belt Starter Generator (BSG) mild-hybrid architecture, the other featuring, in addition to the BSG, a Miller cycle engine combined with an e-supercharger were developed and investigated. Vehicle performances were evaluated both in terms of elasticity maneuvers and of CO2 emissions for type approval and RDE driving cycles. Numerical simulations highlighted potential improvements up to 16% CO2 reduction on RDE driving cycle of a 48 V electrified vehicle featuring a high efficiency powertrain with respect to a EU5 engine and more than 10% of transient performance improvement
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