Executive Design of the Façade Systems. Typologies and Technologies of the Advanced Building Envelopes

The study, developed inside the experimental laboratory Material Balance Research within the Architecture, Built Environment and Construction Engineering-ABC Department at the Politecnico di Milano, examines the advanced façade systems according to the constitutive and typological characters, as well as the functional and applicative requirements such as the expressive, constructive and interactive criteria towards the environmental, perceptive and energy conditions. The work involves to examine the typological and technological constitution of the principal advanced façade systems in the contemporary design and experimental scenario, proposing itself as a knowledge and operational tool currently lacking in the technical literature of the sector at an international level. The work considers the field of advanced façade systems in a scientific way, constituting a support for the study and the executive design. Compared to the pre-existing literature on envelope systems, the work investigates in detail, in an analytical form, the constitution of the components on a typological and geometrical, functional and constructive level, on the basis of the documents and knowledges acquired from the essential contemporary production and construction references. At the same time, the work is configured in manual form as a reference for understanding and application with respect to traditional and complex façade systems. The study is aimed at researchers, designers and, in general, operators in the field of the advanced façade systems, considering that the level of composition of the work is directed at experts in the specific matter, who require a tool of a high explanatory and operational level. This is not a basic text, but a work that goes beyond the literature expressed on the subject at an architectural, descriptive or narrative level. The main topics concern the technological determination of lightweight prefabricated external curtain wall envelopes, according to the development of façade components, also considering multi-material relationships and specialized layering. The thematic in-depth study focuses on structural, connection and interface references related to the functional and application requirements articulated with respect to the main advanced curtain wall types. For each main type of façade, the work provides explanations and scientific information for investigating and designing the advanced façades according to the characteristics of the mullions and transoms façade system (stick system), of the structural sealant glazing façade system, of the unit façade system, of the suspended façade system and of the double skin façade system. The explanation is made with the aid of analytical insights into the physical, connective and interface constitution, supported by details and documents acquired from the advanced production and construction sectors. The book is envisaged to become the first work in a series of texts on the technical and scientific study of the advanced façade systems, planning to deal, in the future, with the contents related to the building site and construction phases, the specific constitution of the production methods, and an in-depth study of the enclosure and cladding materials. The book, intended as a basis for scientific, academy and professional study, is proposed as a useful tool within university courses, specialized and master’s courses, as well as a support for the preparation of expert technicians in the field of façade systems

A parametric-assisted method for 3D generation of as-built BIM models for the built heritage

The paper outlines a parametric-assisted method for the 3D reconstruction and creation of BIM models for the built heritage. The research implements the emerging paradigms of open sourcing, cloud computing and interoperability, employing low-cost technologies (digital photogrammetry) and open source software (Grasshopper for Rhinoceros) which can ease the accessibility to a potential reuse of heritage, typically requiring high specialists and expensive equipment. The research examines the abandoned Albergo Diurno “Venezia” in Milan, heritage with a unique architectural value – a blend of Liberty and Art Deco styles. The process of 3D reconstruction of the ceiling is described. Custom algorithms have been developed to automatically rebuild the complex and irregular geometry from mesh, towards the creation of a NURBS-based 3D model. It is shown how the proposed methodology can streamline the process of data elaboration by reducing arbitrary operations and improve accuracy to preserve geometric irregularities. The associative model allows the automatic improvement in the model definition when more precise input data is feeding the algorithm, offering the opportunity to relate the precision of BIM models in accordance with the needed level of detail (LOD)

Measurement of angular momentum transport in turbulent flow between independently rotating cylinders

We present measurements of the angular momentum flux (torque) in Taylor-Couette flow of water between independently rotating cylinders for all regions of the \(\Omega_1, \Omega_2\) parameter space at high Reynolds numbers, where $\Omega_1$ \(\Omega_2\) is the inner (outer) cylinder angular velocity. We find that the Rossby number Ro = \(\Omega_1 - \Omega_2\)/\Omega_2 fully determines the state and torque $G$ as compared to G(Ro = \infty) \equiv \Gi. The ratio G/\Gi is a linear function of $Ro^{-1}$ in four sections of the parameter space. For flows with radially-increasing angular momentum, our measured torques greatly exceed those of previous experiments [Ji \textit{et al.}, Nature, \textbf{444}, 343 (2006)], but agree with the analysis of Richard and Zahn [Astron. Astrophys., \textbf{347}, 734 (1999)].Comment: 4 pages, 4 figures, to appear in Physical Review Letter

Numerical and Experimental Validation of Active Vibration Control Logic Performance of a Hybrid Noise Control-Based Brick

The limitations of active noise control (ANC) in coping with low frequencies and of passive noise control (PNC) in coping with middle-high frequencies are objects of research that present the potentialities of hybrid noise control (HBC). It aims at combining both of the behaviours by broadening the range of absorbed frequencies. Among the several application fields, the AEC (architecture, engineering, and construction) market can take advantage for those applications in which the noise conditions are caused by sound sources that tune in a broad frequencies range. In this frame, the paper describes the numerical and experimental validation of the active behaviour of an under-development project of a hybrid noise control-based acoustic bricks. The latter intends to embed the potentialities of active vibrational noise control (AVC) and passive destructive interference (PDI) in a unique design of an easy-to-mount, 3D-printed, customisable smart acoustic blocks. Active vibration control, the object of this paper, is provided by a 5-mm thick aluminium circular plate with an attached piezoelectric patch. The vibration of the latter, depending on a specific control law, defines the vibration of the plate itself achieving an abatement of the reflection coefficient. Through mathematical modelling and tests in an impedance tube, the results show that the control logic can reach an average abatement of the reflection coefficient of 82% in the frequency range 144-1007 Hz

The role played by the molecular weight and acetylation degree in modualting the stiffness and elasticity of chitosan gels

A broad library of chitosans was produced varying the molecular weight and the fraction of acetylated units, FA. The produced chitosans were used for the formation of wall-to-wall cylindrical gels through a controlled external gelation using tripolyphosphate (TPP) as cross-linker. The resulting gels were analyzed by rheometry. Viscosity average degree of polymerization (DPv\uaf)\u202f>\u202f152 was shown to be required for the formation of stable gels. Both gel stiffness and gel rupture strength were proportional to the molecular weight regardless of the applied deformation. Increasing acetylation produced a marked reduction of the shear modulus, but, in parallel, switched the networks from rigid and brittle to weak and elastic. Intriguingly, gels made of chitosan with FA\u202f=\u202f0.37 displayed notable elasticity, i.e. up to 90% of applied strain falls into linear regime. These findings suggest that the frequency of glucosamine (D unit) and N-acetyl-glucosamine (A unit) contribute to a subtle structure-property relationship in chitosan-TPP gels

Cognitive modulation of psychophysical, respiratory and autonomic responses to cold pressor test

In healthy subjects with high hypnotisability (highs) under hypnosis, subjectively effective suggestions for analgesia abolish the increases in blood pressure associated with cold pressor test (cpt) by reducing the peripheral vascular resistance. The aim of the present study was to investigate the effects of the suggestions of analgesia on the responses to cpt in healthy highs (n = 22) and in low hypnotisable participants (lows, n = 22) out of hypnosis. Cpt was administered without (CPT) and with suggestions for analgesia (CPT+AN). Psychophysical (pain intensity, pain threshold, cpt duration (time of immersion) and pain tolerance, defined as the difference between cpt duration and pain threshold), respiratory (amplitude and frequency) and autonomic variables (tonic skin conductance, mean RR interval (RR = 1/heart rate), blood pressure, skin blood flow) were studied. The suggestions for analgesia increased cpt duration and RR in both groups, but decreased pain intensity and enhanced pain threshold only in highs; in both groups they did not modulate systolic blood pressure, tonic skin conductance and skin blood flow; thus, increased parasympathetic activity appears responsible for the heart rate reduction induced by suggestions in both groups. In conclusion, our findings show that suggestions modulate pain experience differentially in highs and lows, and are partially effective also in lows. We hypothesize that the mechanisms responsible for the efficacy of suggestions in healthy lows may be involved also in their efficacy in chronic pain patients with low hypnotisability

Test Design Methodology for Time-Domain Immunity Investigations Using Electric Near-Field Probes

This article investigates the possibility to develop time-domain immunity tests using electric near-field probes, for flexible customization of broadband input waveforms injected into specific pins of PCBs. For this purpose, a test design methodology is proposed, which is based on circuit modeling of the injection mechanism on the one hand, and on pulse design and equalization on the other hand. Two circuit models are developed. The former employs measurement/simulation data along with port-reduction techniques to model noise injection through near-field probes by means of internal induced sources. Conversely, the latter model only includes passive components and is derived starting from physical observation of the involved phenomena. Both models are compatible with circuit solvers and can be easily adapted for different traces under test. Since pulse-like noise is usually broadband, suitable stress waveforms are utilized to obtain different noise spectra. Also, in order to precisely control the shape of the waveform reaching the targeted pin, an equalization procedure is employed. These models and techniques can be easily applied to amplification systems originally designed for frequency-domain tests, thus providing a comprehensive solution for the design of broadband immunity tests in the time domain. The feasibility and accuracy of the proposed methodology are proved by full-wave simulations and measurements

Rheology of mixed alginate-hyaluronan aqueous solutions

The present manuscript addresses the description of binary systems of hyaluronan (HA) and alginate (Alg) in semi-concentrated solution. The two polysaccharides were completely miscible in the entire range of relative weight fraction explored at a total polymer concentration of up to 3 % (w/V). The rheological study encompassed steady flow and mechanical spectra for HA/Alg systems at different weight fractions with hyaluronan at different molecular weights. These extensive analyses allowed us to propose a model for the molecular arrangement in solution that envisages a mutual exclusion between the two polysaccharides even though a clear phase separation does not occur. This result may have profound implications when biomaterials based on the combination of alginate and hyaluronan are proposed in the field of biomedical materials