Search results for "Process engineering"
showing 10 items of 931 documents
Fouling mechanism elucidation in membrane bioreactors by bespoke physical cleaning
2018
Abstract Cake layer deposition on a membrane surface can determine both external and internal membrane fouling through negatively affecting the total filtration resistance while exerting a positive effect as a pre-filter. Membranes are usually subjected to a periodic cake layer removal through routine physical cleaning, specifically permeate backwashing of hollow fiber membranes, or enhanced cleaning through, for example, chemically-enhanced backwashing. Physical cake layer removal is crucial for sustaining permeability, yet the effect of different physical cleaning modes remains poorly evaluated. The present work attempts to analyze physical cake layer removal through the application of sp…
Edge pinch instability of liquid metal sheet in a transverse high-frequency AC magnetic field
2006
We analyze the linear stability of the edge of a thin liquid metal layer subject to a transverse high-frequency AC magnetic field. The layer is treated as a perfectly conducting liquid sheet that allows us to solve the problem analytically for both a semi-infinite geometry with a straight edge and a thin disk of finite radius. It is shown that the long-wave perturbations of a straight edge are monotonically unstable when the wave number exceeds some critical value $k_c,$ which is determined by the surface tension and the linear density of the electromagnetic force acting on the edge. The higher the density of electromagnetic force, the shorter the critical wavelength. The perturbations with…
Modulation of the Biological Activity of a Tobacco LTP1 by Lipid Complexation
2004
Plant lipid transfer proteins (LTPs) are small, cysteine-rich proteins secreted into the extracellular space. They belong to the pathogenesis-related proteins (PR-14) family and are believed to be involved in several physiological processes including plant disease resistance, although their precise biological function is still unknown. Here, we show that a recombinant tobacco LTP1 is able to load fatty acids and jasmonic acid. This LTP1 binds to specific plasma membrane sites, previously characterized as elicitin receptors, and is shown to be involved in the activation of plant defense. The biological properties of this LTP1 were compared with those of LTP1-linolenic and LTP1-jasmonic acid…
Multistage recovery process of seaweed pigments: Investigation of ultrasound assisted extraction and ultra-filtration performances
2017
International audience; The objectives of this study were first to evaluate the performance of seaweed pigments’ recovery through ultrasound assisted extraction (UAE) and ultra-filtration (UF), and second to investigate the membrane fouling mechanism and evidence the threshold flux during filtration. The pigments’ recovery from the extract was performed using 5 kDa and 10 kDa ultra-filtration membranes. Results showed that increasing the extraction temperature in the range of 40–60 °C was proportional to chlorophyll extraction efficiency, while the maximal carotenoid yield was achieved at 50 °C. Ultrasonic power (from 100 W to 300 W) facilitated the extraction of both chlorophylls and carot…
The REAPower Project
2019
Abstract Reverse electrodialysis technology has grown significantly in the last decade, gaining a fast increase in its technology readiness level and presenting some interesting examples of pilot systems operating under very different real environments. Among these, one was able to operate in a saltwork in Marsala (Sicily, Italy) with real concentrated brine and real saline waters (i.e., either seawater or brackish water), producing electric power in the order of 1 kW. This pilot plant was one of the main achievements of the European REAPower research project. This chapter presents an overview of the main research efforts and results achieved in the framework of this project starting from t…
Problems and challenges associated with estimating the emissions of organic compounds from indoor materials
2017
Abstract For several years intensive research has been carried out with the aim of developing a database of the types and amounts of pollutants released from indoor materials to the indoor environment. The paper discusses in detail basic problems and challenges encountered when estimating the emissions of chemical compounds released from of indoor materials. Factors affecting the validity of data obtained by using two different types of analytical devices operating in a dynamic mode (the ex-situ methods) or passive mode (the in-situ methods) for collecting the analytes samples from the gaseous phase were discussed. The main advantages and important limitations of specific analytical devices…
Analytical Methodologies for the Determination of Personal Care Products in Water Samples
2014
Personal-care products (PCPs) could reach the aquatic environment and cause a great impact in the aquatic ecosystem. In this sense, the monitoring of these emerging pollutants in the environment yields valuable information. For this reason, analytical methods to determine PCPs in environmental waters are needed. Due to the low concentration of the PCPs, i.e. ng L−1, sensitive methods are needed. This required sensitivity can be achieved by using sensitive analytical techniques during the measurement step, or by employing enrichment techniques during the sample treatment step. Obviously, the combination of both sensitive analytical techniques and extraction techniques considerably improves t…
Study of the correlation between columnar aerosol burden, suspended matter at ground and chemical components in a background European environment
2012
Although routinely monitored by ground based air quality networks, the particulate matter distribution could be eventually better described with remote sensing techniques. However, valid relationships between ground level and columnar ground based quantities should be known beforehand. In this study we have performed a comparison between particulate matter measurements at ground level at different cut sizes (10, 2.5 and 1.0 mm), and the aerosol optical depth obtained by means of a ground based sunphotometer during a multiinstrumental field campaign held in El Arenosillo (Huelva, Spain) from 28 June to 4 July 2006. All the PM fractions were very well correlated with AOD with correlation coef…
Zero Emissions and Bio-refineries for Natural Fibres, Biomaterials and Energy: Genesis of Concepts. Review
2015
Depletion of world recourses, increasing pollution, and climate change make us to shift from linear economy to system economy—an economy of technologies integrated to reach a system of non-polluting zero emissions production. Transition to renewable resources requires replacing the present crude oil refinery by biomass refinery. Along with conventional biomass refinery technologies bioengineering and nano-technologies become significant players in systems designed as clusters of integrated bio-refinery technologies. The authors consider a number of case studies of biomass conversion into value-added chemicals and sources of energy, the steam explosion auto-hydrolysis (SEA) in particular. Re…
Protection of active aroma compound against moisture and oxygen by encapsulation in biopolymeric emulsion-based edible films.
2008
International audience; Edible films made of ι-carrageenans display interesting advantages: good mechanical properties, stabilization of emulsions, and reduction of oxygen transfers. Moreover, the addition of lipids to ι-carrageenan-based films to form emulsified films decreases the transfer of water vapor and can be considered to encapsulate active molecules as flavors. The aim of this study was to better understand the influence of the composition and the structure of the carrageenan-based film matrices on its barrier properties and thus on its capacity to encapsulate and to protect active substances encapsulated. Granulometry, differential scanning calorimetry, and Fourier transform infr…