Our work is aimed at studying the abatement of volatile organic compounds produced by photocatalysts working in different light spectra, investigating the best catalyst able to treat propane in air ...mixtures at high concentrations of the order of thousands of ppm. The experimental data were analyzed in order to extract the relevant parameters and to compare the catalytic activities of three different photocatalysts, TiO2, WO3, and their mixtures. In a reactor box of 1.5 l, photocatalysis processing with TiO2 catalysts gave the best propane depletion of the order of 10% for initial propane concentrations of up to 5000 ppm after 22 min and UV-A lamps with an intensity of 0.4 mW/cm2 while the TiO2 and WO3 catalysts produced an abatement of about 5% after 22 min using UV-C light at an intensity of 5 × 102 mW/cm2.
We compared spectra and intensity light of different sources, such as a UV-A lamp, a UV-C lamp, and a visible bulb, and atmospheric nonthermal plasma emission. Spectroscopic measurements were ...performed with an optical emission spectrometer and radiometric measurements with a radiometer to which UV-A, UV-C, and visible probes were coupled to measure the light intensity per unit surface. For each light source, we measured the emission spectrum and light intensity using different probes and also varying the relative distance. The nonthermal atmospheric plasma was generated by means of a surface barrier dielectric discharge varying the relevant parameters. This work allowed us to create the experimental setup suitable for further studies on volatile organic compound abatement by plasma-catalysis processing and compared it to the photocatalysis techniques based on UV and visible lamps.
The Pliensbachian-Toarcian boundary interval is characterized by a ~ 3‰ negative carbon-isotope excursion (CIE) in organic and inorganic marine and terrestrial archives from sections in Europe, such ...as Peniche (Portugal) and Hawsker Bottoms, Yorkshire (UK). A new high-resolution organic-carbon isotope record, illustrating the same chemostratigraphic feature, is presented from the Southern Hemisphere Arroyo Chacay Melehue section, Chos Malal, Argentina, corroborating the global significance of this disturbance to the carbon cycle. The negative carbon-isotope excursion, mercury and organic-matter enrichment are accompanied by high-resolution ammonite and nannofossil biostratigraphy together with U-Pb CA-ID-TIMS geochronology derived from intercalated volcanic ash beds. A new age of ~ 183.73 + 0.35/- 0.50 Ma for the Pliensbachian-Toarcian boundary, and 182.77 + 0.11/- 0.15 for the tenuicostatum-serpentinum zonal boundary, is assigned based on high-precision U-Pb zircon geochronology and a Bayesian Markov chain Monte Carlo (MCMC) stratigraphic age model.
Blob and hole dynamics is investigated in the sheared rotating plasma column of a simple magnetised torus using two-dimensional time-averaged measurements and conditional averaging analysis. ...Experiments are performed in open field line configuration by adding a vertical magnetic field component to the toroidal one, resulting in a quasistationary equilibrium characterised by vertically elongated profiles. The combined effect of plasma rotation with the vertical field leads to a poloidally asymmetric sheared
E
×
B
flow in the electron diamagnetic direction, pointing downward and upward in the low and high field side of the midplane, respectively, on both sides of the shear layer. Statistical analysis indicates that density fluctuations are dominated by non-Gaussian positive intermittent blob events in the low-density edge region, and negative hole events in the core plasma, whereas the intermediate shear layer corresponds to the blob birth zone featuring Gaussian statistics. Conditional averaging analysis reveals that, in the course of its propagation, a blob breaks off from a structure elongated in the direction of the flow due to the differential stretching in the vicinity of the shear layer. Blobs are convected out of the potential contour and ejected by the fluctuating field to the limiter, while holes stay inside and propagate back into the main plasma. Blobs move poloidally with velocities up to 3.7 km
/
s and radially up to 2.6 km
/
s. These observations confirm the picture where persistent structures provide a means for a net convection of the charged particles to the limiter, across the magnetic field and beyond the edge region of the magnetised plasmas.
A noninvasive diagnostic technique relying on optical emission spectroscopy is used for studying plasma confined in a purely toroidal magnetic field. Visible emission lines of molecular hydrogen were ...specifically targeted. Bi-dimensional structures and poloidal plasma profiles were reconstructed from the emissivity distribution of hydrogen Fulcher system using a tomographic method. A few details concerning the methods employed to capture different emission viewlines, data reduction and tomographic reconstruction techniques are also addressed. We report also the first measurement of the excitation temperature of the
H
2
3c level in the center of the plasma column,
T
exc
=
0.67
±
0.11
eV.
Graphic Abstract
Muon detector for a Muon Collider Aimè, C.; Calzaferri, S.; Casarsa, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2023, Letnik:
1046
Journal Article
Recenzirano
A Muon Collider represents a promising possibility to combine the high energy and luminosity of hadron machines with very precise measurements of lepton colliders. The main challenges, that impact ...both the machine and detector design, arise from the short muon lifetime and the harsh Beam-induced Background (BIB).
Therefore, a full simulation is crucial to understand the feasibility of the experiment implementation. Focusing in particular on the muon system, a preliminary simulation of sensitivity and hit rate reveals that the technology inherited from CLIC, i.e. glass Resistive Plate Chambers, is already at the limit of its rate capability. Thus, alternative MicroPattern Gaseous Detector solutions are under investigation to try to match the required performance. In parallel, studies of muon reconstruction are ongoing.
Results of the muon reconstruction efficiency and BIB sensitivity are presented for multimuon final state processes at a centre-of-mass energy of 1.5TeV. Besides, PICOSEC technology, based on a Micromegas detector coupled to a Cherenkov radiator and equipped with a photocathode, is discussed.
A modular, general method for trapping enzymes within the voids of paper, without chemical activation of cellulose, is reported. Glucose oxidase and peroxidase were crosslinked with poly(acrylic ...acid) via carbodiimide chemistry, producing 3-dimensional networks interlocked in cellulose fibers. Interlocking prevented enzyme activity loss and enhanced the washability and stability.
Crystalline ceria (CeO
2) nanoparticles have been successfully synthesized by a simple and fast microwave-hydrothermal method at 130 °C for 20 min. As-synthesized CeO
2 powders were calcinated at ...500 °C for 1, 2 and 4 h. The products were characterized by thermogravimetric analysis (TG-DTA), X-ray powder diffraction (XRD), field-emission scanning electron microscopy/STEM mode (FEG/STEM), Fourier Transformed-IR and RAMAN spectroscopies. It is shown that synthesized ceria powders have a spherical shape with particle size below 10 nm, a narrow distribution and exhibit weak agglomeration. The FTIR spectrum of the ceria exhibits strong broad band below 700 cm
−
1
which is due to the
δ (Ce–O–C) mode. Raman spectrum is characterized by the presence of a very strong band to 464.5 cm
−
1
. The microwave-hydrothermal method enabled cerium compounds to be synthesized at low temperature and shorter time.
•Fatigue behavior of asphalt mortars containing RAP aggregate was investigated.•The influence of fine aggregate particles and aging on fatigue was studied.•Relationship between fatigue law ...parameters, aging and mix conditions was found.•Parameter A shows a decreasing linear trend with the increase of volume particles.•Parameter B follows an increasing linear trend with the volume aggregate particles.
Fatigue cracking is one of the primary failure mechanisms in asphalt pavements and it predominantly occurs within the mortar phase. For this reason, in recent years, a number of studies were carried out by various researchers to better understand the fatigue mechanism in such a critical mixture phase. In the present work, time sweep tests were performed in strain control mode on asphalt mortars prepared with three volume percentages of fine aggregate at different aging conditions. In particular, two different asphalt mortars were used: one containing Recycled Asphalt Pavement (RAP) materials and the other one composed of the same RAP aggregate skeleton without the aged binder. The influence of the different aging conditions, the presence of the aged binder and the addition of fine aggregate particles on the fatigue resistance of the mortars were evaluated. Moreover, a relationship between the parameters of the obtained fatigue laws and the different aging and mix design conditions was found. The proposed relationship can be easily used to predict the fatigue resistance of a mortar composed of a specific volume concentration of aggregate particles and recycled material. The potential extension of the proposed relationship to mixtures may eventually result in the implementation of a simple analysis tool for practitioner limiting the need for more sophisticated and expensive fatigue tests on asphalt mixtures.
Diaminodiphenylmethane (DDM) curing at several temperatures of a diglycidyl ether of bisphenol A (DGEBA) epoxy resin modified with a poly(ethylene oxide)-
block-poly(propylene oxide)-
...block-poly(ethylene oxide) (PEO–PPO–PEO) block copolymer has been investigated in order to characterize the miscibility and morphological features. Two distinct phases are present for every blends studied except for DGEBA/DDM modified with 10
wt% PEO–PPO–PEO and cured at low temperature. Depending on the curing condition, phase separation takes place at micro or nanoscale due to competition among kinetic and thermodynamic factors. The mechanistic approach used for modeling the curing reactions shows that the formation of epoxy–hydroxyl complex and the auto catalytic process are slightly decreased whilst the noncatalytic process is favoured upon copolymer addition. Modifier addition delays curing process as the influence of both formation of epoxy–hydroxyl complex and catalytic process on reaction rate is higher than the influence of noncatalytic process. A thermodynamic model describing a thermoset/block copolymer considered as only one entity system is proposed. The LCST behaviour allows to elucidate nano or micro separated structures obtained at low and high curing temperatures, respectively.
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