Electrical discharge propagation between GEM foils Utrobicic, A.; Kovacic, M.; Erhardt, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2021, Letnik:
989
Journal Article
Recenzirano
This paper presents the studies of fast sequential discharge formations in neighboring Gas Electron Multiplier foils (so called fast discharge propagations). We report on the characteristics of the ...time delay between the discharges, which has been shown to be of the order of tens of nanoseconds. This time delay decreases both with increasing voltage on the foil where the secondary discharge occurs as well as with decreasing distance between the neighboring foils. Optical measurements of the discharges in two- and three-stage detector setups show that the propagating discharge does not occur directly below the primary discharge, but is displaced from the shortest line between neighboring foils. This observation, together with Scanning Electron Microscope and Energy Dispersive Spectroscopy analyses of the material deposited below the position of the primary discharge provide valuable information on the time evolution of the fast discharge propagation through the detector and its formation mechanism. In the light of these findings, we propose and discuss a new hypothesis for the occurrence of the secondary discharges.
Measurements of the production of forward jets from transversely polarized proton collisions at s=500 GeV conducted at the Relativistic Heavy Ion Collider (RHIC) are reported. Our measured jet cross ...section is consistent with hard scattering expectations. Our measured analyzing power for forward jet production is small and positive, and provides constraints on the Sivers functions that are related to partonic orbital angular momentum through theoretical models.
The aim of this experiment was to investigate airflow velocity influence (0.64, 1.00, 1.50, 2.00, 2.50 and 2.75 m
s
−1) on the kinetics of convection drying of
Jonagold apple, heat transfer and ...average effective diffusion coefficients. Drying was conducted in a convection tray drier at drying temperature of 60 °C using rectangle-shaped (20
×
20
×
5 mm) apple samples. Temperature changes of dried samples, as well as relative humidity and temperature of drying air were measured during the drying process. Rehydratation ratio was used as a parameter for the dried sample quality. Kinetic equations were estimated by using an exponential mathematical model.
The results of calculations corresponded well with experimental data. Two well-defined falling rate periods and a very short constant rate period at lower air velocities were observed. With an increase of the airflow velocity an increase of heat transfer coefficient and effective diffusion coefficient was found. During rehydratation, about 72% of water removed by the drying process was returned.
The influence of drying temperature (60°C, 70°C, 80°C) and fluid-bed drying time (90 min, 135 min, 180 min) on the extraction yield of phenolic compounds and antioxidant activity of extracts were ...investigated. The content of phenolic compounds and antioxidant activity of extracts obtained from wet grape pomace (WGP) were 73.83 mg.sub.GAE g.sub.db.sup.-1, 42.24 mg.sub.CE g.sub.db.sup.-1 30.53 mg g.sub.db.sup.-1 and 0.35 g.sub.inhDPPH g.sub.db.sup.-1 for total Phenolic compounds (TPC), total flavonoids (TF), total extractible proanthocyanidins (TPA), and antioxidant activity (AA), respectively. The applied drying conditions caused the reduction of content of all phenolic compounds down to 13.2 %, 43.1 %, 15.3 % and 21.0 % for TPC, TPA, TF and AA, respectively. The most abundant individual phenolic compound in grape pomace extracts was catechin (5.14-8.52 mg g.sub.db.sup.-1). The highest content of observed compounds was retained when applying drying temperature below 70°C for 90 minutes. Key words: grape pomace, fluid-bed drying, phenolic compounds, antioxidant activity
This is the first of two closely related articles (Paper I and Paper II) that together illustrate how research in physics education has helped guide the design of instruction that has proved ...effective in improving student understanding of atomic spectroscopy. Most of the more than 1000 students who participated in this four-year investigation were science majors enrolled in the introductory calculusbased physics course at the University of Washington (UW) in Seattle, WA, USA. The others included graduate and undergraduate teaching assistants at UW and physics majors in introductory and advanced physics courses at the University of Zagreb, Zagreb, Croatia. About half of the latter group were preservice high school physics teachers. This article (Paper I) describes how several serious conceptual and reasoning difficulties were identified among students as they tried to relate a discrete line spectrum to the energy levels of atoms in a light source. Paper II illustrates how findings from this research informed the development of a tutorial that led to significant improvement in student understanding of atomic emission spectra. 2015 American Association of Physics Teachers.
This is the second of two closely related articles (Paper I and Paper II) that together illustrate how research in physics education has helped guide the design of instruction that has proved ...effective in improving student understanding of atomic spectroscopy. Most of the more than 1000 students who participated in this four-year investigation were science majors enrolled in the introductory calculusbased physics course at the University of Washington (UW) in Seattle, WA, USA. The others included graduate and undergraduate teaching assistants at UW and physics majors in introductory and advanced physics courses at the University of Zagreb, Zagreb, Croatia. About half of the latter group were preservice high school physics teachers. Paper I describes how several conceptual and reasoning difficulties were identified among university students as they tried to relate a discrete line spectrum to the energy levels of atoms in a light source. This second article (Paper II) illustrates how findings from this research informed the development of a tutorial that led to improvement in student understanding of atomic emission spectra. 2015 American Association of Physics Teachers.
This review presents data on the chemical composition of harvest residues and food
industry by-products as widely abundant representatives of lignocellulosic waste biomass. Pretreatment methods, with ...special emphasis on biological methods, are presented
as an important step in utilization of lignocellulosic waste biomass for the production of
sustainable biofuels and high-value chemicals. Special attention was paid to the methods
of lignin isolation and its possible utilization within lignocellulosic biorefinery. The objectives of circular bioeconomy and the main aspects of lignocellulosic biorefinery are
highlighted. Finally, current data on industrial, pilot, and research and development
plants used in Europe for the production of a variety of bio-based products from different
feedstocks are presented.
Lignocellulose biomass, as a renewable and biodegradable carbon source, provides
a wide range of valuable bioproducts. Their utilization requires an efficient conversion
process to break down the ...complex and variable chemical structure of lignocellulose. In
this work, a solid-state fermentation-based pretreatment method for the release of fermentable sugars from corn silage was investigated. The optimal process conditions for
water-soluble sugar extraction were initially explored by response surface methodology
with the aim to achieve the maximum sugar concentration in the extracts. The optimal
extraction conditions were determined: t = 30 min; the liquid-solid ratio L/S = 25 mL g–1;
n = 170 rpm; and T = 30 °C. The changes in the content of water-soluble sugars (glucose,
fructose, sucrose, maltose, maltotriose) were analyzed during seven days of fungal treatment.
The drying and rehydration process of conventionally and organically cultivated carrots was studied and the resulting data were fitted to the Peleg’s model. Carrots were fluid-bed and halogen dried ...and after that soaked in water at room temperature. The Peleg’s model gave a good prediction of water removal and water uptake in all experiments (R>0,994). During the drying process the Peleg’s rate constant (K ₁) was affected by temperature. K ₁ values decreased with the increase of the drying temperature. This relation was linear for fluid-bed drying and exponential for halogen drying, which implied a higher impact of the drying temperature on the dehydration kinetics during halogen drying. The lower K ₁ values for fluid-bed drying suggested higher initial drying rates in comparison with halogen drying at all drying temperatures. The temperature dependence of 1/K ₁ followed an Arrhenius-type relationship. Both Peleg’s rehydration constants (K ₁ and K ₂) increased with the increase of the drying temperature. This implied regular decrease of initial rehydration rate and water uptake with the increase of the drying temperature.
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