Thermal behaviour assessment of a novel vertical greenery module system: first results of a long-term monitoring campaign in an outdoor test cell

Vertical greenery modular systems (VGMSs) are an increasingly widespread building envelope solution aimed at improving the aesthetical quality of both new and existing façades, contemporarily achieving high energy efficiency performance. Within a research project, a new prototype of VGMS was developed, designed and tested. An experimental monitoring campaign was carried out on a test cell located in Turin (northern Italy), aimed at assessing both biometric parameters and energy-related issues. Two different types of growing media and two plant species, Lonicera nitida L. and Bergenia cordifolia L., have been tested on a south-facing lightweight wall. Results have been compared to the same wall without VGMS and plaster finished, in order to characterise the thermal insulation effectiveness in the winter period and the heat gain reduction in the summer period. Measured equivalent thermal transmittance values of the green modular system showed a 40 % reduction, when compared to the plastered wall, thus noticeably impacting on the energy crossing the façade during the heating season. Benefits of the VGMS are measured also during the summer season, when the presence of vegetation lowers the outdoor surface temperatures of the wall up to 23 °C compared to the plastered finishing, with a positive effect on outdoor comfort and urban heat island mitigation. Nevertheless, as far as the entering energies are concerned, not significant reduction was observed for VGMS, compared to the reference plastered wall, since the green coverage acts as a thermal buffer and solar radiation is stored and slowly released to the indoor environment.     

Towards biomimetic models of the reduced [FeFe]-hydrogenase that preserve the key structural features of the enzyme active site; a DFT investigation

[FeFe]-hydrogenases are the most efficient biological catalysts available for the H₂ evolution reaction. Their active site – the H-cluster – features a diiron subsite which has the peculiar characteristic of bearing cyanide groups hydrogen-bonded to the apoprotein as well as carbonyl ligands. Notably, one of the CO ligands is disposed in bridging position between the metal centers. This allows one of the Fe ions to retain a square pyramidal coordination – which determines the assumption of the so-called “rotated structure” – with a vacant coordination site in trans to the μ-CO group, ready to bind protons when the active site is in the Fe^IFe^I state. Many Fe^IFe^I biomimetic models have been synthesized and characterized so far, but most of them fail to reproduce the orientation of the diatomic ligands that is observed in the enzyme active site.     

An IR molding system for direct shaping of thermoplastics

A new molding technique is proposed to directly mold small parts from thermoplastic pellets. A small molding machine was designed and fabricated: the mold consisted of a transparent glass and a metallic frame; an infrared (IR) lamp provided the heat for the pellet melting. Molding tests were carried out by using three commercial thermoplastics and two metallic molds. Molding time and IR lamp power were changed to extract a moldability window for each combination of material and metallic mold. In the best process conditions, a high quality of the samples was obtained in terms of mold filling and surface aesthetics. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

In situ synchrotron X-ray micro-tomography study of pitting corrosion in stainless steel

Pitting corrosion of stainless steel has been investigated with high-resolution in situ X-ray microtomography. The growth of pits at the tip of stainless steel pins has been observed with 3D microtomography under different conditions of applied current and cell potential. The results demonstrate how pits evolve in stainless steel, forming a characteristic “lacy” cover of perforated metal. In addition, it is shown how the shape of pits becomes modified by MnS inclusions.     

A new and rapid method for the evaluation of the liquid-solid contact resulting from liquid injection into a fluidized bed

Liquid feeds are injected into fluidized bed reactors such as fluid cokers, fluid catalytic crackers and gas-phase polymerization reactors. In these industrial processes, it is of crucial importance to optimize the contact between the injected liquid and the bed solids to minimize agglomeration, to ensure good reactor operability, and to allow reactions to proceed under minimum heat and mass transfer limitations in order to maximize the yields of valuable products. It has been shown [P. House, M. Saberian, C. Briens, F. Berruti, E. Chan, Injection of a liquid spray into a fluidized bed: particle-liquid mixing and impact on fluid coker yields. Industrial & Engineering Chemistry Research 43 (2004) 5663-5669., S. Bruhns, J. Werther, An investigation of the mechanism of liquid injection into fluidized beds. AIChE Journal 51 (2005) 766-775] that the nozzle technology and the operating conditions have a significant effect on the quality of the liquid-solid interaction resulting from the injection of gas-atomized liquid feed. The goal of this study was to develop a rapid and reliable experimental technique to assess the liquid-solid contact efficiency resulting from the injection of a liquid feed into a fluidized bed. Air-fluidized silica sand particles were first charged by triboelectrification as a result of their random collisions with the inner walls of the fluidized bed. Immediately after the injection of water through an aerated nozzle, the fluidization air was stopped and the wetted bed solids were allowed to settle. While the bed was defluidized, the triboelectric charges accumulated on the particles migrated to a grounded electrode through the low-resistance paths offered by the conductive liquid. A stronger electric current flowing through the electrode indicated that the liquid was more evenly distributed on the solid particles. The intensity of the current flowing through the electrode was, therefore, used to define a spray nozzle performance index. This technique was used to examine the effect of increasing the nozzle aeration, and, specifically, the gas-to-liquid mass ratio (G/L) through the nozzle on the liquid-solid contact efficiency. The results showed that changing the nozzle geometry can change how the contact efficiency between atomized liquid and fluidized solids varies with (G/L), especially at relatively high G/L ratios. A model of the time-evolution of the electric current generated during defluidization of the bed solids is also presented.     

A Bifunctional Copper Catalyst for the One Pot-One Step Esterification?+?Hydrogenation of Tall Oil Fatty Acids

An efficient copper catalyst for the one-pot one-step hydrogenation?+?esterification of unsaturated free fatty acids is described. The high selectivity in hydrogenation promoted by copper, combined with the high activity in esterification observed with solid mixed oxides allows one to directly obtain stabilized methyl esters.     

Hierarchically Structured Zeolite Bodies: Assembling Micro‐, Meso‐, and Macroporosity Levels in Complex Materials with Enhanced Properties

Engineering levels of porosity in hierarchical zeolites is a vibrant area of research with remarkable application potential. To gain practical relevance, the superior properties observed for the as‐synthesized powders have to be preserved when they are shaped into suitable technical geometries. Herein, mechanically stable millimeter‐sized bodies are prepared by granulation of mesoporous ZSM‐5 zeolite powders using an attapulgite clay binder. Alkaline treatment of conventional zeolite granules is demonstrated to be unsuitable for this purpose. Multiple techniques are applied to characterize mesoporous zeolite granules with respect to their conventional zeolite counterparts, thus establishing the impact of binder inclusion and granulation on their respective properties. The intrinsic structure and acidity of the zeolite are retained post‐structuring. Gas adsorption and mercury porosimetry confirm the presence of interconnected micro‐, meso‐, and macropores. A wide range of imaging techniques permits visualization of the particle properties, phase distribution, and consequent origins of the distinct levels of porosity within the zeolite granules. The superior adsorption properties of the hierarchical ZSM‐5 zeolite granules are demonstrated using cyclohexane, toluene, and isopropyl alcohol as probe molecules.     

Diode Laser Cure of Serigraphic Ink

Laser polymerization of serigraphic ink was performed by diode laser (DL). Experimental tests were carried out by depositing a commercial solvent-based ink on a polyvinylchloride (PVC) sheet. Ink cure was obtained using a 940 nm emission wavelength DL with an almost rectangular spot. We considered different values for laser power, scanning rate and focalization distance and several behaviors were observed depending on the laser fluence, from the uncured ink state to substrate warpage and degradation. Both ink thickness measurement and scratch tests were conducted on laser-processed samples. Analysis of experimental results shows that the full cure can occur within an extremely short time and at very low power values.     

Highly porous polycaprolactone-45S5 Bioglass® scaffolds for bone tissue engineering

Highly porous biocompatible composites made of polycaprolactone (PCL) and 45S5 Bioglass® (BG) were prepared by a solid–liquid phase separation method (SLPS). The composites were obtained with BG weight contents varying in the range 0–50%, using either dimethylcarbonate (DMC) or dioxane (DIOX) as solvent, and ethanol as extracting medium. The porosity of the scaffolds was estimated to be about 88–92%. Mechanical properties showed a dependence on the amount of BG in the composites, but also on the kind of solvent used for preparation, composites prepared with DIOX showing enhanced stress at deformation with respect to composites prepared with DMC (stress at 60% of deformation being as high as 214 ± 17 kPa for DIOX-prepared composites and 98 ± 24 kPa for DMC-prepared ones, with 50 wt/wt_PCL% of glass), as well as higher elastic modulus (whose value was 251 ± 32 kPa for DIOX-prepared scaffolds and 156 ± 36 kPa for DMC-prepared ones, always with 50 wt/wt_PCL% of glass). The ability of the composites to induce precipitation of hydroxyapatite was positively evaluated by means of immersion in simulated body fluid and the best results were achieved with high glass amounts (50 wt/wt_PCL%). In vitro tests of cytotoxicity and osteoblast proliferation showed that, even if the scaffolds are to be considered non-cytotoxic, cells suffer from the scarce wettability of the composites.