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Learning from the past: the lesson of the Japanese house
No full textThanks to the great spiritual value linked to it, the Japanese house is one of the oldest and most fascinating architectural constructs of the eastern world. The religion and the environment of this region have had a central role in the evolution of the domestic spaces and in the choice of materials used. The eastern architects have kept some canons of construction that modern designers still use. These models have been source of inspiration of the greatest minds of the architectural landscape of the 20th century. The following analysis tries to understand how such cultural bases have defined construction choices, carefully describing all the spaces that characterize the domestic environment. The Japanese culture concerning daily life at home is very different from ours in the west; there is a different collocation of the spiritual value assigned to some rooms in the hierarchy of project prioritization: within the eastern mindset one should guarantee the harmony of spaces that are able to satisfy the spiritual needs of everyone that lives in that house. The Japanese house is a new world: every space is evolving thanks to its versatility. Lights and shadows coexist as they mingle with nature, another factor in understanding the ideology of Japanese architects. In the following research, besides a detailed description of the central elements, incorporates where necessary a comparison with the western world of thought. All the influences will be analysed, with a particular view to the architectural features that have influenced the Modern Movement. The traditional Japanese architecture offers an important reflection, highlighting some simple points that we often forget because our western lifestyle is based increasingly on materialism. Where, if not our house, should be our refuge where we can dedicate ourselves to the search for inner harmony
Production of PCL nanoparticles by flash nanoprecipitation for controlled release of caffeine
No full textCaffeine (CAF) is one of the most consumed drug worldwide due to its large application in food, pharmaceuticals, cosmetics and supplements; upon oral administration caffeine is cleared into the stomach in 20 minutes and absorbed into the blood within 1 hour [1]. Polycaprolactone (PCL) is biodegradable polymer extensively studied in drug delivery applications where long lasting releases are required [2]. Caffeine was encapsulated in PCL nanoparticles by exploiting the Flash nano-precitation technique which is well known method to encapsulate hydrophobic dru[3], but not yet studied on hydrophilic active principles. The nanoparticles were produced in a confined impinging jet mixer by dissolving caffeine alternatively in the solvent (acetone or in the antisolvent (water). The effect of the process parameters on the mean particle diameter and zeta potential of the nanoparticles was investigated by Dynamic Light Scattering. A novel methodology to accurately quantify drug Loading Capacity (LC) and Encapsulation Efficiency was studied and implemented. The in vitro release kinetic was assessed by dynamic dialysis method. Nanoparticle with average diameter ranging from 250 to 500 nm were successfully produced, the mean size was correlated to the flow rate. LC and EE were assessed in the range of 10-45% and 5-25% respectively. The release test showed a 1st order kinetic with a peak of caffeine in blood mimicking solution delayed to 6 hours
Lumped Parameter and Three-Dimensional CFD Simulation of a Variable Displacement Vane Pump for Engine Lubrication
No full textThe paper describes the modelling and the experimental tests of a variable displacement vane pump for engine lubrication. The approach used for the simulation has involved 3D commercial tools for tuning a 0D customized model implemented in the LMS Amesim® environment. Different leakage paths are considered and the axial clearances are variable to take into account the deformation of the pump cover, calculated through a finite element analysis with ANSYS®. The vane tip clearances are calculated as function of the dynamic equilibrium equation of the vanes. The displacement control takes into account the internal forces on the stator due to the pressure in all variable chambers and to the contact force exerted by the vanes. The discharge coefficients in the resistive components have been tuned by means of a complete 3D transient model of the pump built with PumpLinx®. The tuned 0D model has been proved to be reliable for the determination of the steady-state flow-speed and flow-pressure curves, with a correct estimation of the internal leakages and of the pressure imposed by the displacement control. The pump has been also tested using a simplified circuit and a fair agreement has been found in the evaluation of the delivery pressure ripple
Interfacial Effects in Solid-Liquid Electrolytes for Improved Stability and Performance of Dye-Sensitized Solar Cells
No full textWith the purpose of achieving stable dye-sensitized solar cells (DSSCs) with high efficiency, a new type of soft matter electrolyte is tested in which specific amounts of nanosized silica particles are finely dispersed in short-chained polyethylene glycol dimethylether encompassing an iodide/triiodide redox mediator. This results in a solid-liquid composite having synergistic electrical and favorable mechanical properties. The combination of interfacial effects and particle network formation promotes enhanced ion transport, which directly impacts the short-circuit photocurrent density. Thorough analysis reveals that this newly elaborated class of electrolytes is able to improve, at the same time, the thermal and long-term stability of DSSCs, as well as power conversion efficiency under standard and lower irradiation intensities. Lab-scale devices with champion efficiency exceeding 11% under attenuated sunlight (20 mW cm-2, with a compact TiO2 blocking layer) are obtained, along with impressively stable performance under both thermal stress and light soaking in an indoor environment (>96% performance retention after 2500 h of accelerated aging under full sun alternated with thermal ramps), matching the durability criteria applied to silicon solar cells for outdoor applications. The new findings might foster widespread practical application of DSSCs
A Novel Approach to Enhance the Mechanical Strength and Electrical and Thermal Conductivity of Cu-GNP Nanocomposites
No full textCopper/graphene nanoplatelet (GNP) nanocomposites were produced by a wet mixing method followed by a classical powder metallurgy technique. A qualitative evaluation of the structure of graphene after mixing indicated that wet mixing is an appropriate dispersion method. Thereafter, the effects of two post-processing techniques such as repressing-annealing and hot isostatic pressing (HIP) on density, interfacial bonding, hardness, and thermal and electrical conductivity of the nanocomposites were analyzed. Density evaluations showed that the relative density of specimens increased after the post-processing steps so that after HIPing almost full densification was achieved. The Vickers hardness of specimens increased considerably after the post-processing techniques. The thermal conductivity of pure copper was very low in the case of the as-sintered samples containing 2 to 3 pct porosity and increased considerably to a maximum value in the case of HIPed samples which contained only 0.1 to 0.2 pct porosity. Electrical conductivity measurements showed that by increasing the graphene content electrical conductivity decreased
The significant imbalance of nZEB energy need for heating and cooling in Italian climatic zones
No full textBuilding energy performance requirements aiming at the nZEB target have been recently established by the national legislation. In Italy, the requirements are verified through the notional reference building, whose U-values are reduced in two steps: up to 2018 and since 2019 for public buildings, and up to 2020 and since 2021 for all other buildings. This might cause a reduction of the heating need but an increase of the cooling need. The objective of the study is to investigate in which conditions and extent a significant imbalance of the energy needs occurs. Different building types and climatic zones are considered
Low thrust interplanetary transfers: second approximation computation of planetocentric phases
No full textChemico-osmotic transport properties and mechanical behaviour of a natural sodium bentonite
No full textThe relevance of the semipermeable properties of bentonites, which affect both their transport processes and mechanical behaviour, was assessed through the determination of two parameters: the reflection coefficient, w, and the swell coefficient, w1. Laboratory tests were conducted, using a new apparatus, with the aim of measuring w and w1 of a natural sodium bentonite, while varying both the bentonite void ratio and the solute concentration of the sodium chloride (NaCl) solutions in contact with the bentonite specimens. The obtained results show that both parameters can be interpreted through a mechanistic model, in which the electric charge of clay particles is taken into account via a single parameter, csk0, that is referred to as the "solid skeleton electric charge concentration". A constant value of csk,0 = 110 mM was found to provide an accurate interpretation of all the experimental data, at least within the investigated range of bentonite void ratios (e varying from 3.33 to 4.18) and NaCl concentrations of the external bulk solutions (cs varying from 5 mM to 90 mM). The obtained results support the hypothesis that both chemical osmosis and swelling pressure are macroscopic manifestations of the same interactions, which occur at the microscopic scale, between the clay particles and the ions contained in the pore solution, and that both of them can be modelled through a single theoretical framework
Laboratory characterization of the chemo-hydro-mechanical behaviour of chemically sensitive clays
No full textThis paper focuses on the chemo-hydro-mechanical behaviour of active soils, with special reference to the effects of pore water salinity on the volumetric and shear strength behaviour. Fundamental coupled processes governing transport of solvent and solute in active materials are briefly recalled, together with a model for the volumetric behaviour at the macroscopic scale based on the evaluation of the electrical interaction between clay particles and ions in the pore water at the particle level. Experimental procedures for the laboratory characterization of active soils are then discussed in light of these models and of other well-known phenomenological evidences. Both modified and conventional experimental apparatus can be used in the geotechnical characterization: interpretation of test results requires anyway referring to models accounting for the chemo-mechanical coupling. Experimental data discussed in the paper proceed from tests on bentonites used for waste containment and from tests on a natural illitic-smectitic soil from a marly clay formation in the Langhe area
Historical quakeproof building systems in Italy: constructional skill and normative experimentation. Notes for a critical comparison
No full textItalian Building heritage shows a vulnerability of striking topical interest after the last earthquake in Central Italy. To every historical observation of building seismic vulnerability it mostly corresponds an intense search of more effective quakeproof criteria, and of new standards to attenuate the risk. Much less energy is historically devoted to investigating whether the collapse is to be attributed to noncompliant and faulty construction or whether the real full requirement compliance validated the regulatory criteria at that time in force. The introduction of normative discontinuities was preferred instead of continuously verifying historical constructive skills. The study of wood frame-based systems is of great interest: particularly important are the so-called beneventan "case baraccate" (1627) or the "case baraccate" of the Bourbon period (1783): the latter proved a really favorable behavior in the Messina quake (1908). But the general drive to use reinforced concrete systems and the economic pulses leaded to the substitution of "casa baraccata" with reinforced concrete housings, despite the quake collapsed some such buildings. Political and regulatory wills with economic lobbies appear to overcome constructive factors, favoring techniques easily modelled, rather than retaining local skills that proved to translate in effective, sustainable techniques linked to the historical local memory