18 research outputs found
Chromatic sunshade cladding unit
No full textThe present invention relates to sunshade units for internal or external cladding of the transparent structures of a building façade comprising a plurality of lamellae (201) each having a substantially flat and elongated conformation along a respective development axis (B), and a structure (220,220') supporting the lamellae configured to support the plurality of lamellae (201) in a condition of parallel and spaced apart lamellae along a direction orthogonal to the development axes (B), the structure (220,220') supporting the lamellae being configured to support the plurality of lamellae (201) in a rotatable manner about a rotation axis parallel to or coincident with its development axis (B), characterized in that each lamella (201) of the plurality of lamellae (201) includes at least one surface portion which comprises at least a reflective layer (10) having at least one reflective surface (11), and a chromatic diffusion layer (20) having a first surface (21) proximal to the reflective surface (11) and a second surface (23), opposite and substantially parallel to the first, configured to be illuminated by incident light, wherein the chromatic diffusion layer (20) comprises a nano-pillar (70) or nano-pore (30) structure in a first material having a first refractive index (n1), immersed in a second material having a second refractive index (n2) other than the first (n1), in which the first and second materials are substantially non-absorbing or transparent to electromagnetic radiations with wavelength comprised in the visible spectrum, wherein the ratio ( nM/nm > between a higher refractive index (nm) and a lower refractive index (nm) chosen between the first (n1) and the second (n2) refractive indexes is comprised between 1.05 and 3, wherein the nano-pillars (71) or nano-pores (31) locally have a development along a main direction not parallel to the first surface (21) and to the second surface (23) of the chromatic diffusion layer, and the nano-pillar (70) or nano-pore (30) structure is characterized by a plurality of geometric parameters comprising a pillar diameter or pore diameter (dP), a pillar length or pore length (lp) along said non-parallel direction, a surface density of nano-pillars or nano-pores (Dp) and a porosity (Pp) of structure (30,70), and wherein the plurality of geometric parameters is configured to provide a higher regular reflectance for wavelengths of the incident light comprised in the range of red with respect to wavelengths of the incident light comprised in the range of blue and a higher diffuse reflectance for wavelengths of the incident light comprised in the range of blue with respect to wavelengths of the incident light comprised in the range of red
Tackling the Challenging Determination of Trace Elements in Ultrapure Silicon Carbide by LA-ICP-MS
No full textThe goal of accurately quantifying trace elements in ultrapure silicon carbide (SiC) with a purity target of 5N (99.999% purity) was addressed. The unsuitability of microwave-assisted acid digestion followed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis was proved to depend mainly on the contamination induced by memory effects of PTFE microwave vessels and by the purity levels of acids, even if highly pure ones were used in a clean environment. A new analytical protocol for the direct analysis of the solid material by laser ablation coupled with ICP-MS (LA-ICP-MS) was then exploited. Different samples were studied; the best results were obtained by embedding SiC (powders or grains) in epoxy resin. This technique has the great advantage of avoiding any source of external contamination, as grinding, pressing and sintering pretreatments are totally unnecessary. Two different laser wavelengths (266 and 193 nm) were tested, and best results were obtained with the 266 nm laser. The optimized protocol allows the determination of elements down to the sub-mg/kg level with a good accuracy level
Oriented TiO2 nanostructured pillar arrays: Synthesis and characterization
No full textA new method for the synthesis of parallelly aligned TiO2 micropillars, either pure or fixed to a rigid carbon support was investigated. Mild oxidation treatment at 500°C under a flow of N2 containing 1% of oxygen led to the formation of parallelly oriented elongated pillars that emerge from a compact amorphous carbon phase. The pillars were mesophorous and constitute of partially cemented anatase particles with diameters in the 10-20 nm range and a surface area of approximately 60 m2/g. A solution of 2-furanmethanol and Ti isopropoxide was prepared at room temperature. The solution was then heated to obtain a solid resin. It was observed that pure TiO2 pillars that constitute of nearly pure anatase phase can be obtained by a further prolonged oxidation process in the presence of 10% oxygen
Zwitterion-Coated Iron Oxide Nanoparticles: Surface Chemistry and Intracellular Uptake by Hepatocarcinoma (HepG2) Cells
No full textNanoparticles
(NPs) have received much attention in recent years
for their diverse potential biomedical applications. However, the
synthesis of NPs with desired biodistribution and pharmacokinetics
is still a major challenge, with NP size and surface chemistry being
the main factors determining the behavior of NPs in vivo. Here we
report on the surface chemistry and in vitro cellular uptake of magnetic
iron oxide NPs coated with zwitterionic dopamine sulfonate (ZDS).
ZDS-coated NPs were compared to similar iron oxide NPs coated with
PEG-like 2-[2-(2-methoxyethoxy)ethoxy]acetic acid (MEEA) to investigate
how surface chemistry affects their in vitro behavior. ZDS-coated
NPs had a very dense coating, guaranteeing high colloidal stability
in several aqueous media and negligible interaction with proteins.
Treatment of HepG2 cells with increasing doses (2.5–100 μg
Fe/mL) of ZDS-coated iron oxide NPs had no effect on cell viability
and resulted in a low, dose-dependent NP uptake, inferior than most
reported data for the internalization of iron oxide NPs by HepG2 cells.
MEEA-coated NPs were scarcely stable and formed micrometer-sized aggregates
in aqueous media. They decreased cell viability for dose ≥50
μg Fe/mL, and were more efficiently internalized than ZDS-coated
NPs. In conclusion, our data indicate that the ZDS layer prevented
both aggregation and sedimentation of iron oxide NPs and formed a
biocompatible coating that did not display any biocorona effect. The
very low cellular uptake of ZDS-coated iron NPs can be useful to achieve
highly selective targeting upon specific functionalization
From isolated Ag+ ions to aggregated Ag0 nano-clusters in silver-exchanged ETS-10 molecular sieve: a reversible behavior
No full text
(I<sub>2</sub>)<i><sub>n</sub></i> Encapsulation inside TiO<sub>2</sub>: A Way To Tune Photoactivity in the Visible Region
No full textWe report on the synthesis of nanovoid-structured TiO2 material via a sol−gel route using titanium
isopropoxide as precursor. The nanovoids are formed during the thermal treatment in air at 773 K. The
surfaces of internal cavities are populated by the partial oxidation products of the organic part of the Ti
precursor (CO2, hydrogen carbonates, and residual isopropoxide groups). The thermal treatment in air at
773 K allows the maintainence, in the internal voids, of the encapsulated species. Addition of iodine in the
synthesis procedure results in a new nanovoid-structured titanium oxide able to absorb light in the whole
visible part of the electromagnetic spectrum. The origin of this absorption is attributed to the presence of
(I2)n adducts encapsulated in the nanocavities. These species coexist with partial combustion products of
isopropoxide groups. Due to the protection of the TiO2 walls, the (I2)n adducts are not destroyed by thermal
treatments in air. We have investigated whether the electron promoted in the excited state of the dye*
molecule (upon absorption of visible light from the (I2)n adducts) can be injected into either the TiO2
conduction band or some titanium-localized acceptor, followed by migration of the injected electron to the
surface where it reduces adsorbed organic molecules. Preliminarily experiments conducted with sunlight
show that the surface-specific efficiency of this process, tested by following the degradation of methylene
blue, is about 10 times higher than that of the P25 commercial TiO2 photocatalyst
<i>In Situ</i> Infrared Emission Spectroscopy for Quantitative Gas-Phase Measurement under High Temperature Reaction Conditions: An Analytical Method for Methane by Means of an Innovative Small-Volume Flowing Cell
No full text We have used infrared emission spectroscopy (IRES) in order to perform in situ studies under flowing gas-phase conditions. When the small-volume cell developed herein is used, we can (1) observe emission spectra from a hot gas-phase sample having an effective volume much less than one milliliter, (2) observe spectra of typical molecular species present, and (3) observe spectra of the more important molecular species down to below 10% and in some cases even as low as 1%. In addition, an analytical method has been derived in order to conduct quantitative studies under typical reaction conditions. We show that simplifications can be made in the data acquisition and handling for a direct linear correlation between band intensity and concentration with only simple background correction. The practical lower limit for methane in the present setup is approximately 0.5–1% v/v depending on the selected temperature. Our data were collected at 500, 600, and 700 °C, respectively. The major features of the present cell design are fairly simple and basically formed by a quartz tube (outer diameter=6 mm, inner diameter=4 mm) inside a metal pipe and two tubular ceramic heaters. This simple setup has advantages and attractive features that have extended the application of IRES to new fields and, in particular, for in situ studies of hydrocarbon reactions at different residence times at high temperature. </jats:p
Rapid Assessment of Intertidal Wetland Sediments
No full textUrbanization of coastal areas poses a severe threat to ecologically valuable intertidal wetlands. This paper presents a pragmatic approach called Rapid Assessment for Intertidal Wetland Sediments (RAITWS) for evaluating the sediment quality of intertidal wetlands. RAITWS involves construction of reference groups, selection of a subset of environmental variables, matching of test sites to reference groups, prediction of the benthic fauna community structure (e. g. of macroinvertebrates) at test sites, evaluation of the Observation to Expectation ratio (O/E ratio), quantification of environmental variables with series of dynamic numerical models, and interpretation of the O/E findings. The proposed method extends the existing rapid biological assessment approach from static to dynamic applications. In particular, RAITWS provides a fast method of assessing intertidal wetland sites which are undergoing ecological change due to nearby coastal development.</p
