Search results for "EXCHANGE"
showing 10 items of 2035 documents
Experimental and Numerical Simulations of Flow and Heat Transfer in Heat Exchanger Elements Using Liquid Crystal Thermography
2004
Experimental and numerical investigation of heat transfer and fluid flow were conducted for classic heat exchanger elements (flat plate with fin-tubes in-line, staggered and with vortex generators) and corrugated-undulated ducts under transitional and weakly turbulent conditions. The dependence of average heat transfer and pressure drop on Reynolds number and geometrical parameters was investigated. Distributions of local heat transfer coefficient were obtained by using liquid crystal thermography and surface-averaged values were computed. Three-dimensional numerical simulations were conducted by a finite-volume method using a low-Reynolds number k-e model under the assumption of fully deve…
Bentonite-ionic liquid composites for Congo red removal from aqueous solutions
2021
Abstract Clay-organic composites have attracted great interest due to their ability to remove various contaminants from wastewater. The surfactants are the most commonly used organic compounds for clay modification. However, cationic surfactants are toxic and can be environmentally hazardous. Ionic liquids are a new promising alternative to the cationic surfactants due to lesser toxicity and appropriate thermal stability. The research aim is to prepare an environmentally friendly new class of clay sorbents modified with ionic liquids for potential applications in wastewater treatment from the textile industry. Imidazolium-based ionic liquids with different lengths of alkyl chains were inter…
Synthesis, Characterization and Sorption Capacity Examination for a Novel Hydrogel Composite Based on Gellan Gum and Graphene Oxide (GG/GO)
2020
A novel hydrogel composite based on gellan gum and graphene oxide (GG/GO) was synthesized, characterized and tested for sorption capacity in this work. The microstructural, thermogravimetric and spectroscopic analysis confirmed the formation of the GG/GO composite. Comparative batch sorption experiments revealed a sorption capacity of the GG/GO composite for Zn (II) ions of approximately 2.3 higher than that of pure GG. The GG/GO composite exhibits a maximum sorption capacity of 272.57 mg/g at a pH of Zn (II) initial solution of 6. Generally, the sorption capacity of the sorbents is approximately 1.5 higher in slightly acidic conditions (pH 6) comparative with that for strong acidic conditi…
Structural Characterisation of Complex Layered Double Hydroxides and TGA-GC-MS Study on Thermal Response and Carbonate Contamination in Nitrate- and …
2015
Layered double hydroxides (LDHs) are versatile materials used for intercalating bioactive molecules in the fields of pharmaceuticals, nutraceuticals and cosmetics, with the purpose of protecting them from degradation, enhancing their water solubility to increase bioavailability and improving their pharmacokinetic properties and formulation stability. Moreover, LDHs are used in various technological applications to improve stability and processability. The crystal chemistry of hydrotalcite-like compounds was investigated by X-ray powder diffraction (XRPD), automated electron diffraction tomography (ADT) and thermogravimetric analysis (TGA)-GC-MS to shed light on the mechanisms involved in io…
Nanoporous alumina membranes filled with solid acid for thin film fuel cells at intermediate temperatures
2004
Thin film fuel cells have been fabricated by impregnation of inorganic porous membranes with inorganic proton conductor. Anodic alumina membranes (50 μm thick and pore diameter of 200 nm), filled with CsHSO4 salt have been used as protonic conductor in a hydrogen-oxygen fuel cell working between 423 and 443 K in dry atmosphere. Polarization curves at 433 K showing ohmic control with open circuit values near 0.8 V and short circuit current around 8 mA cm−2 have been obtained. Possible causes of degradation as well as alternative routes to overcome some of the problems encountered with this approach will be reported. Keywords: Solid acid, Anodic alumina membranes, Pore filling, Thin film fuel…
The photovoltaic growth in the European Union requires stronger RES support
2016
Since the adoption of the EU Directive, 2001/77/EC, the production of electricity from renewable energy sources has progressed. Apart from the indicative target proposed by the Directive, actually no other tools of policy monitoring exist. To fill this gap, we propose a dynamic method able to capture this multidimensional phenomenon, providing an assessment tool to measure the technical efficiency performances of EU countries in the photovoltaic sector (1996–2010). Results show how technical efficiencies of countries are, from one hand, due to problems belonging to the economic and political contexts in which they operate, on the other hand driven by specific political support schemes adopt…
NG2 regulates directional migration of oligodendrocyte precursor cells via Rho GTPases and polarity complex proteins.
2013
The transmembrane proteoglycan NG2 is expressed by oligodendrocyte precursor cells (OPC), which migrate to axons during developmental myelination and remyelinate in the adult after migration to injured sites. Highly invasive glial tumors also express NG2. Despite the fact that NG2 has been implicated in control of OPC migration, its mode of action remains unknown. Here, we show in vitro and in vivo that NG2 controls migration of OPC through the regulation of cell polarity. In stab wounds in adult mice we show that NG2 controls orientation of OPC toward the wound. NG2 stimulates RhoA activity at the cell periphery via the MUPP1/Syx1 signaling pathway, which favors the bipolar shape of migrat…
A critical evaluation of caplacizumab for the treatment of acquired thrombotic thrombocytopenic purpura
2020
Introduction: Acquired thrombotic thrombocytopenic purpura (aTTP) is a thrombotic microangiopathy caused by inhibitory autoantibodies against ADAMTS13 protein. Until recently, the combination of plasma exchange (PEX) and immunosuppression has been the standard front-line treatment in this disorder. However, aTTP-related mortality, refractoriness, and relapse are still a matter of concern. Areas covered: The better understanding of the pathophysiological mechanisms of aTTP has allowed substantial improvements in the diagnosis and treatment of this disease. Recently, the novel anti-VWF nanobody caplacizumab has been approved for acute episodes of aTTP. Caplacizumab is capable to block the adh…
Do fluorescence and transient absorption probe the same intramolecular charge transfer state of 4-(dimethylamino)benzonitrile?
2009
International audience; We present here the results of time-resolved absorption and emission experiments for 4-(dimethylamino)benzonitrile in solution, which suggest that the fluorescent intramolecular charge transfer (ICT) state may differ from the twisted ICT (TICT) state observed in transient absorption.
Macroeconomic Fluctuations as a Source of Luck in CEO Compensation
2010
Macroeconomic fluctuations such as interest rate and exchange rate can be considered sources of good or bad “luck” for corporate performance. Incentive effects of performance-based compensation for management may be weakened or biased by macroeconomic influences depending on the ability of management to adjust for operations. We decompose the impacts on CEO compensation to distinguish between macroeconomic (anticipated and unanticipated) and “intrinsic” sources. Total CEO compensation is measured by including options awarded or options exercised. Both measures depend strongly on variations in macro factors but the time patterns differ. The macroeconomic factors increased total awarded compe…