Single-step preparation of inverse opal titania films by the doctor blade technique

The difficulty to infiltrate solid-state hole semiconductors within micron-thick porous titania films is one of the major limiting factors for the achievement of efficient solid-state dye-sensitized solar cells. It was already shown that through the ordered interconnected pores of an inverse opal, the large surface area of several microns thick titania film can be easily decorated with a dye and filled with a solid-state hole semiconductor. In this paper, we show that ordered inverse opal mesoporous thick films of TiO2 with these characteristics can be obtained by using a slurry of monodispersed polystyrene spheres and a titania-lactate precursor deposited by the doctor blade technique. The mechanism of formation of the inverse opal is also discussed

Effects of the blending ratio on the design of keratin/poly (Butylene succinate) nanofibers for drug delivery applications

In recent years there has been a growing interest in the use of proteins as biocompatible and environmentally friendly biomolecules for the design of wound healing and drug delivery sys-tems. Keratin is a fascinating protein, obtainable from several keratinous biomasses such as wool, hair or nails, with intrinsic bioactive properties including stimulatory effects on wound repair and excellent carrier capability. In this work keratin/poly (butylene succinate) blend solutions with functional properties tunable by manipulating the polymer blending ratios were prepared by using 1,1,1,3,3,3‐hexafluoroisopropanol as common solvent. Afterwards, these solutions doped with rho-damine B (RhB), were electrospun into blend mats and the drug release mechanism and kinetics as a function of blend composition was studied, in order to understand the potential of such mem-branes as drug delivery systems. The electrophoresis analysis carried out on keratin revealed that the solvent used does not degrade the protein. Moreover, all the blend solutions showed a non‐ Newtonian behavior, among which the Keratin/PBS 70/30 and 30/70 ones showed an amplified orientation ability of the polymer chains when subjected to a shear stress. Therefore, the resulting nan-ofibers showed thinner mean diameters and narrower diameter distributions compared to the Ker-atin/PBS 50/50 blend solution. The thermal stability and the mechanical properties of the blend elec-trospun mats improved by increasing the PBS content. Finally, the RhB release rate increased by increasing the keratin content of the mats and the drug diffused as drug‐protein complex

Developing keratin sponges with tunable morphologies and controlled antioxidant properties induced by doping with polydopamine (PDA) nanoparticles

his work investigates the preparation of wool keratin sponges by freeze-drying procedure starting form keratin aqueous solutions. The study highlights the correlations between process parameters (protein concentration and freezing rate) and the chemical-physical properties of the final sponges. In particular, as the keratin concentration increases from 1 to 20% wt, the mean pore size and the porosity decrease from 62 to 37 mu m and from 94 to 50% respectively, while the chemical stability in physiological conditions increases, as well as the thermal stability and the elastic modulus. On the other hand, the increase of the freezing rate affects the design of sponges that appear as stacked leaflets structures with oriented pores. Moreover, in order to confer to keratin sponges antioxidant properties, polydopamine (PDA) nanoparticles were used as fillers. To this end, PDA nanoparticles of about 130 nm were successfully dispersed in the sponges, bestowing time-dependent anti-oxidant properties on the scaffolds, with no significant modification of sponges morphological structure as well as reduction of the thermal stability and mechanical behaviour

Core-shell graphene oxide-polymer hollow fibers as water filters with enhanced performance and selectivity

Commercial hollow fiber filters for micro-and ultrafiltration are based on size exclusion and do not allow the removal of small molecules such as antibiotics. Here, we demonstrate that a graphene oxide (GO) layer can be firmly immobilized either inside or outside polyethersulfone-polyvinylpyrrolidone hollow fiber (Versatile PES®, hereafter PES) modules and that the resulting core-shell fibers inherits the microfiltration ability of the pristine PES fibers and the adsorption selectivity of GO. GO nanosheets were deposited on the fiber surface by filtration of a GO suspension through a PES cartridge (cut-off 0.1-0.2 μm), then fixed by thermal annealing at 80 °C, rendering the GO coating stably fixed and unsoluble. The filtration cut-off, retention selectivity and efficiency of the resulting inner and outer modified hollow fibers (HF-GO) were tested by performing filtration on water and bovine plasma spiked with bovine serum albumin (BSA, 66 kDa, ≈15 nm size), monodisperse polystyrene nanoparticles (52 nm and 303 nm sizes), with two quinolonic antibiotics (ciprofloxacin and ofloxacin) and rhodamine B (RhB). These tests showed that the microfiltration capability of PES was retained by HF-GO, and in addition the GO coating can capture the molecular contaminants while letting through BSA and smaller polystyrene nanoparticles. Combined XRD, molecular modelling and adsorption experiments show that the separation mechanism does not rely only on physical size exclusion, but involves intercalation of solute molecules between the GO layers

I Codici Commerciali

Il capitolo analizza le problematiche collegate all'utilizzo de codici commerciali o industriali in termofluidodinamic

Caratterizzazione di sedimenti da dragaggio: valutazione della mobilit\ue0 di inquinanti inorganici, e degli effetti del trattamento di Soil Washing

Nell\u2019ambito della caratterizzazione di fanghi da dragaggio portuali, ci si \ue8 occupati di valutare la mobilit\ue0 degli inquinanti inorganici presenti. Si \ue8 lavorato su sedimenti reali e sui prodotti in uscita dal trattamento di Soil Washing. Si \ue8 operato tramite test di cessione, a pH controllato ed a percolazione, per valutare la lisciviabilit\ue0 delle componenti inorganiche in processi analoghi a quelli che subiscono i sedimenti una volta stoccati nell\u2019ambiente. Si \ue8 inteso valutare l\u2019effetto del trattamento sulla mobilit\ue0 degli inquinanti. Questo permette di valutare la pericolosit\ue0 dei materiali, passando dall\u2019inquadramento nelle normative per gli inquinanti nei suoli a quelle per gli eluati per l\u2019ammissibilit\ue0 in discarica dei rifiuti inerti o non pericolos

Caratterizzazione di fanghi da dragaggio tramite test di cessione: mobilit\ue0 degli inquinanti inorganici

In questo lavoro ci si \ue8 occupati, nell\u2019ambito della caratterizzazione di fanghi da dragaggio portuali, di valutare la mobilit\ue0 degli inquinanti inorganici presenti. Si \ue8 lavorato su un sedimento reale. Si \ue8 operato tramite test di cessione, a pH controllato ed a percolazione, per valutare la lisciviabilit\ue0 delle componenti inorganiche in processi analoghi a quelli che possono subire i sedimenti una volta stoccati nell\u2019ambiente. Uno dei trattamenti possibili sui sedimenti per migliorarne le caratteristiche in funzione del riutilizzo \ue8 il Soil Washing, si \ue8 quindi adottata la procedura di caratterizzazione sul sedimento in ingresso al trattamento e sui prodotti in uscita (sabbie e fini). In questo modo \ue8 possibile valutare gli effetti del trattamento sulla mobilit\ue0 degli inquinanti. Questo permette inoltre di valutare la pericolosit\ue0 dei materiali, passando dall\u2019inquadramento nelle normative per gli inquinanti nei suoli a quelle per gli eluati per l\u2019ammissibilit\ue0 in discarica dei rifiuti inerti o non pericolosi. La matrice influenza i risultati di questi test, ed \ue8 quindi importante effettuarli su campioni reali

Influence of experimental parameters on the determination of tetragonal distortion in heterostructures by LACBED

The LACBED technique has been applied to the determination of the tetragonal distortion in Si1-xGex/Si heterostructures, which are of great interest in the device technology. The strain determination has been performed on plan sections in an analytical electron microscope. The agreement between this strain value and the tetragonal distortion is influenced mainly by the local sample flatness and the acceleration voltage

Radiation Heat Transfer Effect on Natural Convection in Asymmetrically Heated Vertical Channels

Heat and mass transfer in vertical channels with a heated ribbed wall is investigated numerically and the results coming from two different CFD codes are compared. The codes are based on finite volume (Fluent 6.2) and on finite element approach (COMSOL Multiphysics) respectively. The channel is two dimensional, is set in vertical position and it is bounded by a heated ribbed wall facing an adiabatic smooth wall. The effects of the aspect ratio, the temperature difference between the heated wall and the ambient, the thermal conductivity of the ribs and the emissivity of the heated wall are considered. The results show that small aspect ratios and low thermal conductivity ribs have a negative effect on heat and mass transfer. High temperature differences and high emission coefficients for the heated wall, on the contrary, lead to a strong enhancement of the channel heat and mass transfer