Search results for "mass [leptoquark]"
showing 10 items of 519 documents
Mass transfer in ducts with transpiring walls
2019
Abstract The problem of mass transfer in ducts with transpiring walls is analysed: the concepts of “solvent” and “solute” fluxes are introduced, all possible sign combinations for these fluxes are considered, and relevant examples from membrane processes such as electrodialysis, reverse osmosis and filtration are identified. Besides the dimensionless numbers commonly defined in studying flow and mass transfer problems, new dimensionless quantities appropriate to transpiration problems are introduced, and their limiting values, associated with “drying”, “desalting” and “saturation” conditions, are identified. A simple model predicting the Sherwood number Sh under all possible flux sign combi…
Heat and mass flows coupled with stress in a continuous medium
1996
Abstract The present paper is concerned with the formulation of the generalization of theories describing heat and mass flows in a continuous medium. The considerations are based on the non-equilibrium thermodynamics. As a result the fundamental equations for the mass and heat fluxes and for the thermodynamic and mechanical fields, are obtained and the corresponding set of differential equations is formulated. Certain differences are pointed out between the general theories presented here and the thermodiffusion theory and the theory of mixtures. A thermodynamic variational principle is constructed. All the investigations concern only flows with a single temperature field. Copyright © 1996 …
Assessment of the Mass and Surface Area of the Scots Pine (Pinus sylvestris L.) Needles
2022
The assessment of the surface area of all leaves from a tree crown is regarded as one of the key parameters in scaling ecophysiological processes, such as growth, carbon budget, and water management. The purpose of this study was to investigate the variation of the mass and surface area of Scots pine needles, obtained from trees growing in the same habitat conditions but at different stock densities, therefore occupying different biosocial positions. The mass of needles and the leaf area index (LAI) were determined for an even-aged 33-year-old Scots pine stand located at a fresh mixed coniferous forest site in southwest Poland (50°32′ N; 17°42′ E). The needles, collected…
The application of headspace gas chromatography coupled to tandem quadrupole mass spectrometry for the analysis of furan in baby food samples.
2015
Abstract Selective methodology employing a tandem quadrupole mass spectrometer coupled to a gas chromatograph with headspace autosampler (HS-GC–MS/MS) was elaborated in this study. Application of the elaborated procedure resulted in a limit of detection of 0.021 μg kg −1 and a limit of quantification of 0.071 μg kg −1 . The mean recoveries during in-house validation ranged from 89% to 109%, and coefficients of variation for repeatability ranged from 4% to 11%. The proposed analytical method was applied for monitoring the furan content of 30 commercial baby food samples available on the Latvian retail market. The level of furan found in these samples varied from 0.45 to 81.9 μg kg −1 , indic…
Demethanization of aqueous anaerobic effluents using a polydimethylsiloxane membrane module: Mass transfer, fouling and feasibility
2017
Abstract The performance, fouling and feasibility of a polydimethylsiloxane hollow fibre membrane module for in situ methane degasification from the effluent of an Expanded Granular Sludge Bed anaerobic reactor has been investigated. Experiments at different operational conditions were carried out (liquid flow, sweep gas flow and vacuum pressure) with maximum removal efficiency (77%) at lowest flow-rate (0.4 L h−1), highest vacuum gauge pressure (−800 mbar) and liquid flowing in lumen side. Mass transport analysis denoted a considerably higher methane transfer than that predicted (attributed to liquid oversaturation). An enhancement factor for liquid phase has been proposed to correlate the…
Predicting breakthrough of vanadium in fixed-bed absorbent columns with complex groundwater chemistries: A multi-component granular ferric hydroxide−…
2020
Granular ferric hydroxide (GFH) is often used for fixed bed adsorbent (FBA) columns in groundwater purification units around the world to remove arsenate contaminations. Groundwater can contain also other toxic (e.g., antimonite and vanadate) and non-toxic oxo-anions (phosphate and silicic acid) that are known to affect FBA lifetimes. Therefore, understanding the breakthrough of toxic compounds intended for removal by FBA is essential to their design, and is important to predict accurately breakthrough curves (BTCs) for FBAs in waterworks to plan future operating costs. Rapid small-scale column tests (RSCCT) and pilot-scale FBA were used to simulate vanadate BTCs for complex groundwater che…
Nuts and dried fruits: Natural occurrence of emerging Fusarium mycotoxins
2013
Abstract The occurrence of enniatins (ENs) and beauvericin (BEA) in nuts, dried fruits and dates available in Valencia (Spain) was surveyed in this study. To do this, seventy-four samples of nuts, dried fruits and dates were analyzed for the determination of mycotoxin contamination. Mycotoxins were identified and quantified using an ultrasonic-C18 extraction and LC–MS/MS with a triple quadrupole (QqQ) mass analyzer. The frequencies of contamination of nuts, shell, dried fruits and dates were 50%, 80%, 35.7% and 83.3%, respectively. Enniatin A (ENA) was the most predominant EN found in nuts (45.2%) while ENB was the most common EN found in dates (58.3%). The analytical results of the shell s…
Viewing the Sun as an X-ray star
2003
The Sun is the late-type star we can study with the highest level of detail. In the interpretation of stellar data, therefore, it is often assumed that the physical processes of the coronae of late-type stars are similar to those of the solar corona, i.e. the "solar-stellar analogy". In order to investigate the validity of this assumption, we have started a program to study systematically the Sun as an X-ray star. Our program aims to explore how far the solar model can be applied to other stars. In this paper we review the results obtained from these studies and, in particular, we discuss the variability of a star identical to the Sun during its cycle, the contribution of different coronal …
Scale-up and viscosity effects on gas–liquid mass transfer rates in unbaffled stirred tanks
2018
Abstract The interest in the process industry on unbaffled stirred tanks has greatly expanded in the last years because they may bring about significant advantages in a number of applications, including biochemical, food and pharmaceutical processes where the presence of baffles is undesirable for several reasons. Despite their application potential, unbaffled vessels still lack fundamental information, due to the fact that only recently their capabilities have started being dug out. The lack of information on scale up effects is possibly the main reason hindering practical applications. In this work the influence of vessel size and liquid viscosity on the mass transfer performance in unbaf…
Modeling of a continuous photocatalytic reactor for isovaleraldehyde oxidation: Effect of different operating parameters and chemical degradation pat…
2013
International audience; An investigation of isovaleraldehyde (ISOV) photocatalytic oxidation was conducted at initial concentrations ranging from 25 to 150 mg/m3 and different relative humidities (5-90% RH) in order to characterize the process performances close to indoor air conditions. Experiments were carried out in two different reactors: cylinder and flat-plate photoreactor (planar reactor) at different air gap (20-60 mm) and gas residence times (0.67-5.0 s). A plug flow reactor system was developed in order to perform kinetic studies of (i) isovaleraldehyde removal, (ii) selectivity of CO2, (iii) byproducts formation and removal. It appears that ISOV removal efficiencies increased wit…