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Auteur : Grafiati
Publié le 18 mai 2024

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1

Boberič, Gordana, Oliver Bajt, Boris Šket et Jadran Faganeli. « Photochemical degradation of butyl acrylate in different aqueous media ». Chemosphere 37, no 1 (juillet 1998) : 33–40. http://dx.doi.org/10.1016/s0045-6535(98)00036-8.

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Nguyen, Huu Van, Son Tung Luu et E. G. Rakov. « Solubility of Functionalized Carbon Nanofibers in Different Aqueous Media ». Fullerenes, Nanotubes and Carbon Nanostructures 20, no 4-7 (mai 2012) : 429–33. http://dx.doi.org/10.1080/1536383x.2012.655552.

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Karg, Matthias, Natascha Schelero, Claudia Oppel, Michael Gradzielski, Thomas Hellweg et Regine von Klitzing. « Versatile Phase Transfer of Gold Nanoparticles from Aqueous Media to Different Organic Media ». Chemistry – A European Journal 17, no 16 (23 mars 2011) : 4648–54. http://dx.doi.org/10.1002/chem.201003340.

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Amini-Fazl, Mohammad Sadegh, Hamid Mobedi et Jalal Barzin. « Investigation of aqueous stability of taxol in different release media ». Drug Development and Industrial Pharmacy 40, no 4 (17 avril 2013) : 519–26. http://dx.doi.org/10.3109/03639045.2013.771646.

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Müller, B. « Corrosion inhibition of different metal pigments in aqueous alkaline media ». Corrosion Science 43, no 6 (juin 2001) : 1155–64. http://dx.doi.org/10.1016/s0010-938x(00)00134-7.

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Gouda, Abdelaziz, Francesca Soavi et Clara Santato. « Eumelanin electrodes in buffered aqueous media at different pH values ». Electrochimica Acta 347 (juillet 2020) : 136250. http://dx.doi.org/10.1016/j.electacta.2020.136250.

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Alva-Ensastegui, J. C., M. Palomar-Pardavé, M. Romero-Romo et M. T. Ramírez-Silva. « Quercetin spectrofluorometric quantification in aqueous media using different surfactants as fluorescence promoters ». RSC Advances 8, no 20 (2018) : 10980–86. http://dx.doi.org/10.1039/c8ra01213j.

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Michałowska-Kaczmarczyk, Anna M., et Tadeusz Michałowski. « Evaluation of Transition Points between Different Solid Phases in Aqueous Media ». Journal of Analytical Sciences, Methods and Instrumentation 04, no 03 (2014) : 87–94. http://dx.doi.org/10.4236/jasmi.2014.43012.

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Khorfan, S., J. Stas et M. Kassem. « Stripping of uranium from Dehpa/kerosene solvents by different aqueous media ». Journal of Radioanalytical and Nuclear Chemistry 238, no 1-2 (décembre 1998) : 145–48. http://dx.doi.org/10.1007/bf02385370.

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Nazari, Babak, Zahra Ranjbar, Ra’na Rafiei Hashjin, Amir Rezvani Moghaddam, Gelareh Momen et Behnaz Ranjbar. « Dispersing graphene in aqueous media : Investigating the effect of different surfactants ». Colloids and Surfaces A : Physicochemical and Engineering Aspects 582 (décembre 2019) : 123870. http://dx.doi.org/10.1016/j.colsurfa.2019.123870.

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Kamdi, Zakiah, et K. T. Voisey. « Corrosion Mechanism of Tungsten Carbide-Based Coatings in Different Aqueous Media ». Key Engineering Materials 694 (mai 2016) : 167–71. http://dx.doi.org/10.4028/www.scientific.net/kem.694.167.

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In cermet coatings with both ceramic and metal present, these can have very different corrosion potentials. Therefore, determination of the corrosion behaviour performance and its mechanism is crucial, especially in very acidic and alkaline environment. A conventional high velocity oxy-fuel (HVOF) tungsten carbide (WC)-Co coatings and a weld overlay tungsten carbide-nickel alloy cermet with carbide size of ~0.3-5 mm and ~50-140 mm respectively are used. Potentiodynamic tests are carried out in acidic and alkaline electrolytes: 0.5 M sulphuric acid, pH 0.45 and bentonite drilling fluid, pH 10.45. The behaviour of both coating types tested were pH dependent. The HVOF coating showed preferential dissolution of the binder in both electrolytes, with material loss being approximately twice as severe in the 0.5 M sulphuric acid compared to the alkaline drilling fluid. For the weld overlay coatings, with the larger carbide particles, the Ni3B phase in the binder was preferentially removed in the acidic electrolyte whereas the Ni rich dendritic phase underwent preferential dissolution in the alkaline environment.
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Kulvietis, Vytautas, Giedrė Streckytė et Ričardas Rotomskis. « Spectroscopic investigations of CdTe quantum dot stability in different aqueous media ». Lithuanian Journal of Physics 51, no 2 (2011) : 163–71. http://dx.doi.org/10.3952/lithjphys.51206.

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Mena-Durán, Cinthia J., P. Quintana, Romeli Barbosa, J. M. Baas et B. Escobar. « Characteristics of Hydrochars Prepared from Cassava Residues Using Different Aqueous Media ». Waste and Biomass Valorization 11, no 6 (17 janvier 2019) : 2857–62. http://dx.doi.org/10.1007/s12649-018-00561-1.

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Gutiérrez-Pichel, Manuel, Silvia Barbosa, Pablo Taboada et Víctor Mosquera. « Surface properties of some amphiphilic antidepressant drugs in different aqueous media ». Colloid and Polymer Science 281, no 6 (24 janvier 2003) : 575–79. http://dx.doi.org/10.1007/s00396-002-0817-6.

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15

Strauss, Volker, Shankara Gayathri Radhakrishnan, Jenny Malig, Norbert Jux et Dirk M. Guldi. « Catching metallic nitride endohedral fullerenes in organic and aqueous media ». Journal of Porphyrins and Phthalocyanines 20, no 08n11 (août 2016) : 1025–33. http://dx.doi.org/10.1142/s1088424616500711.

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Two bis-tetraphenylporphyrin tweezers-like conjugates bearing different linkers have been characterized by means of electrochemical and photophysical methods. The thrust of this work was the complexation of these bis-porphyrins with C[Formula: see text] and metallic nitride endohedral fullerenes (MNEF) like Sc3N@C[Formula: see text] in organic and in aqueus media — studied by a combination of steady-state and time-resolved spectroscopies. In the context of charge separation evidence for the formation of the 1a[Formula: see text]-Sc3N@C[Formula: see text] and 1c[Formula: see text]-Sc3N@C[Formula: see text] charge separated states in organic and aqueous media, respectively, came from transient absorption spectroscopy. Multi-wavelength analyses afforded charge separated state lifetimes of around 400 ps.
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Zhang, Xue Mei, Ling Pang, Shao Peng Wu et Guo Fu Zhang. « Effect of Different Media Aqueous Solution on Road Performance of Asphalt Mixtures ». Materials Science Forum 913 (février 2018) : 1070–75. http://dx.doi.org/10.4028/www.scientific.net/msf.913.1070.

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Servicing in the natural environment, asphalt pavement is often exposed to the various aqueous solution, however, the effect of different media aqueous solution on road performance of asphalt mixtures remains ambiguous. In this study, the influences of water, acid, alkali and salt solution on volume of air voids (VV), tensile strength rate (TSR), low temperature performance of 70# asphalt mixtures and SBS modified asphalt mixtures were investigated through freeze-thaw cycles test, void ratio test, Lottman test and Three-point Bending Fracture (TBF) test. The results indicated that freeze–thaw cycles influenced the road performance of asphalt mixtures significantly, increased the air void of asphalt mixtures, and reduced tensile strength ratio and failure strain of asphalt mixtures. Compared with the distilled water, the damage of acid, alkali and salt solution on the road performances of asphalt mixtures were more serious, especially alkali solution to tensile strength rate and failure strains in low temperature, and salt solution to VV. The moisture corrosion resistance of SBS modified asphalt mixtures is better than that of 70# asphalt mixtures.
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17

Demir-Cakan, Rezan, M. Rosa Palacin et Laurence Croguennec. « Rechargeable aqueous electrolyte batteries : from univalent to multivalent cation chemistry ». Journal of Materials Chemistry A 7, no 36 (2019) : 20519–39. http://dx.doi.org/10.1039/c9ta04735b.

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18

Save, Maud, Yohann Guillaneuf et Robert G. Gilbert. « Controlled Radical Polymerization in Aqueous Dispersed Media ». Australian Journal of Chemistry 59, no 10 (2006) : 693. http://dx.doi.org/10.1071/ch06308.

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Controlled radical polymerization (CRP), sometimes also termed ‘living’ radical polymerization, offers the potential to create a wide range of polymer architectures, and its implementation in aqueous dispersed media (e.g. emulsion polymerization, used on a vast scale industrially) opens the way to large-scale manufacture of products based on this technique. Until recently, implementing CRP in aqueous dispersed media was plagued with problems such as loss of ‘living’ character and loss of colloidal stability. This review examines the basic mechanistic processes in free-radical polymerization in aqueous dispersed media (e.g. emulsion polymerization), and then examines, through this mechanistic understanding, the new techniques that have been developed over the last few years to implement CRP successfully in emulsion polymerizations and related processes. The strategies leading to these successes can thus be understood in terms of the various mechanisms which dominate CRP systems in dispersed media; these mechanisms are sometimes quite different from those in conventional free-radical polymerization in these media.
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19

Suzana Casaes de Jesus Teodoro, Matheus Chaves de Jesus, Crissia dos Santos Rocha, Roseane Santos Oliveira et Ingrid Lessa Leal. « Chemical Evaluation and Probiotic Potential of Kefir Different Nutrient Media ». JOURNAL OF BIOENGINEERING, TECHNOLOGIES AND HEALTH 6, no 1 (8 avril 2023) : 10–14. http://dx.doi.org/10.34178/jbth.v6i1.272.

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Kefir is a gelatinous mass composed of bacteria and yeast. This study aims to develop beverages obtained from kefir grains’ fermentation in different nutrient media. Thus, kefir fermentation was performed in an aqueous solution of sucrose, whole milk, whole grape juice, and water-soluble coconut extract. The fermentation process was analyzed from grain growth, beverage yield, lactic acid determination, pH, total soluble solids, and microbiological analysis. The results showed the beverages had pH and lactic acid values following the legislation. Furthermore, it identified the probiotic potential of the coconut and milk water-soluble extract beverages.
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20

Barmar, M., et B. Kaffashi. « Rheological Behavior of HEUR Mixtures in Aqueous Media ». International Polymer Processing 22, no 2 (1 avril 2007) : 146–50. http://dx.doi.org/10.1515/ipp-2007-0004.

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Abstract Three S-G HEUR thickeners were synthesized by a step growth polymerization technique of poly (ethylene oxide) (PEO) and dicyclohexylmethane – 4,40-diisocyanate (H12MDI) and then end capped with two monofunctional aliphatic alcohols. These polymers were mixed together according to the hydrophilic and hydrophobic nature of their segments. Based on this, two sets of associating polymers were introduced. In one set, the samples had identical hydrophobic segments while in the other one, hydrophilic segments were similar. The steady shear viscosity profiles of aqueous solutions of all models were determined. In addition, aqueous binary mixtures with various ratios of the S-G HEUR models were studied using steady state and dynamic rheometry. It is suggested that combinations of associating polymers with different size of hydrophobic segments and similar hydrophilic segments produce an associative polymer-like behavior. However, the combination of those with similar long hydrophobic segments and different hydrophilic segments at similar weight ratio in solution falls short of displaying an associative polymer – like behavior.
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21

Charnyi, D. V., et Yu A. Onanko. « ANALYSIS OF ELECTROSTATIC PROPERTIES OF POLYSTYRENE FOAM FILTRATION MEDIA ». Міжвідомчий тематичний науковий збірник "Меліорація і водне господарство", no 2 (12 décembre 2019) : 167–74. http://dx.doi.org/10.31073/mivg201902-183.

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The relevance of research. The analysis of the aqueous suspension filtration initial stage through clean polystyrene foam filtration media carried out. Such feature of its work as hydro-sorting is considered. The degree of imbalance and interaction with other electrostatic systems in aqueous suspension determines the layer of potential-forming ions, which is formed around the core of the system. It determines system’s sign and most of the electrical double layer charge. It is usually determined using a physical quantity such as electrostatic or ζ-potential. The aim of this work is to determine the electrostatic properties of polystyrene foam granules and the degree of influence on the process of retaining various nature colloidal particles on their surface when filtering an aqueous suspension through them. Research results. The relationship between the sizes of polystyrene foam granules and the concentrations of electrostatic charge on their surface analyzed. Using the Poison-Boltzmann theory, a relationship between an electrostatic charge and an electric double layer of polystyrene foam granules in aqueous suspension showed. The importance of the ζ-potential researching for controlling of colloidal suspensions filtering process substantiated. The electrostatic properties of different morphology colloids studied. Analysis of research data confirms the hypothesis of a very close connection between the various morphologies colloids ζ-potential magnitude and their electric double layer interaction force with electric double layer of polystyrene foam granules in an aqueous suspension. This means that the polystyrene foam filter “charging” time is closely connected to the values of colloids ζ-potential in the filtered aqueous suspension. Conclusions. The initial filtration stage through clean polystyrene foam media is significantly different from the main stage of filtration due to the electrostatic interaction forces predominance. The time difference of the colloidal crusts complete formation completion on polystyrene foam granules of different diameters is so insignificant that it can be neglected and this time is considered the same for polystyrene foam granules of different diameters. Regardless of the origin nature, the retention intensity of the colloids by polystyrene foam filtration media granules and, consequently, the polystyrene filter “charging” time is directly depends on their z-potential value.
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Suzuki, Shigeru, Shinya Suzuki, Sang-Koo Kwon, Kiyoshi Kanie, Atsushi Muramatsu, Yoshio Waseda, Masaki Sakurai, Eiichiro Matsubara, Makoto Okui et Sei Fukushima. « Characterization of Fine Particles of Different Iron Oxides Formed in Aqueous Media ». e-Journal of Surface Science and Nanotechnology 4 (2006) : 352–58. http://dx.doi.org/10.1380/ejssnt.2006.352.

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Chakraborty, Moumita, et Amiya Kumar Panda. « Spectral behaviour of eosin Y in different solvents and aqueous surfactant media ». Spectrochimica Acta Part A : Molecular and Biomolecular Spectroscopy 81, no 1 (octobre 2011) : 458–65. http://dx.doi.org/10.1016/j.saa.2011.06.038.

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Sáez, Verónica, M. D. Esclapez Vicente, Ángel J. Frías-Ferrer, Pedro Bonete et José González-García. « Electrochemical degradation of perchloroethylene in aqueous media : An approach to different strategies ». Water Research 43, no 8 (mai 2009) : 2169–78. http://dx.doi.org/10.1016/j.watres.2009.02.019.

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Myronyuk, L. I., I. F. Myronyuk, V. L. Chelyadyn, V. M. Sachko, M. A. Nazarkovsky, R. Leboda, J. Skubiszewska-Zięba et V. M. Gun’ko. « Structural and morphological features of crystalline nanotitania synthesized in different aqueous media ». Chemical Physics Letters 583 (septembre 2013) : 103–8. http://dx.doi.org/10.1016/j.cplett.2013.07.068.

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Chattoraj, I., S. Baunack, M. Stoica et A. Gebert. « Electrochemical response of Fe65.5Cr4Mo4Ga4P12 C5B5.5 bulk amorphous alloy in different aqueous media ». Materials and Corrosion 55, no 1 (janvier 2004) : 36–42. http://dx.doi.org/10.1002/maco.200303693.

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Rocha, Vanessa Vilela, Bruno Athaíde Bacelar, Isabela Domingues Coelho et Péter Ludvig. « Nanocomposites Produced with the Addition of Carbon Nanotubes Dispersed on the Surface of Cement Particles Using Different Non-Aqueous Media ». C 9, no 1 (22 mars 2023) : 36. http://dx.doi.org/10.3390/c9010036.

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The inclusion of carbon nanotubes (CNTs) in cementitious composites has been studied due to their electrical, thermal, and mechanical enhancing properties. Considering the hydrophobic characteristics of CNTs, these nanomaterials need to be well dispersed in the aqueous media in which they are inserted to guarantee those gains. Among the methods applied to produce such composites is the dispersion of CNTs on the surface of anhydrous cement particles using non-aqueous suspensions such as acetone, ethanol, or isopropanol. Even though those non-aqueous media have been individually studied by researchers, comparisons of the efficiency of CNTs dispersion was not found in the literature. Therefore, as a novelty, the present article aims to analyze the influence of the addition of the multi-walled CNTs dispersed in the cited three types of non-aqueous suspensions on the cement paste’s electrical and mechanical properties. Pastes containing 0%, 0.5%, and 1.0% of CNTs were prepared on the surface of anhydrous cement particles using a pre-dispersion technique based on simultaneous sonication and mechanical agitation in the three cited media. Tests to determine electric-volumetric resistivity, compressive strength, and splitting tensile strength were performed. It was observed that acetone dispersion decreases the cement paste’s electrical resistivity, even without the addition of CNTs. The cementitious composites with CNTs demonstrated increased mechanical strength (both compressive and tensile) using all three dispersion media. Statistical analysis (analysis of variance—ANOVA—and Tukey’s Test) was performed to evaluate the significance of the results.
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Franzén, Robert, et Youjun Xu. « Review on green chemistry — Suzuki cross coupling in aqueous media ». Canadian Journal of Chemistry 83, no 3 (1 mars 2005) : 266–72. http://dx.doi.org/10.1139/v05-048.

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The Suzuki cross-coupling reaction is a very efficient, reliable, and environmentally friendly method for the introduction of novel carbon–carbon bonds into molecules. This review summarizes recent advances in the use of the reaction in aqueous media with a focus on different types of ligands and the ligandless protocols currently in use. Several synthetic targets for the reaction have been mentioned. The work summarizes recent results from studies on asymmetric Suzuki reactions performed in organic – aqueous mixed solvents.Key words: Suzuki reaction, green chemistry, metal-catalyzed cross-coupling reactions, aqueous synthesis media.
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Noori, Noor AlhudaMahammed, et Mahdi A. Mohammed. « Preparation ofZincOxide Nanoparticles by UV-IrradiationMethod in Two Different Media ». Journal of Physics : Conference Series 2114, no 1 (1 décembre 2021) : 012079. http://dx.doi.org/10.1088/1742-6596/2114/1/012079.

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Abstract The zinc oxidenanoparticles(ZnO NPs) were prepared in two media. The first one was in an aqueous medium resulting from the reaction of urea with zinc acetate at 0.3M concentration in both of them in deionized water. The second medium is a polymeric solution which is a dissolving of 4% polyvinyl alcohol (PVA)in deionized water with zinc acetate. The nanoparticles were obtained after the two media were irradiated with ultraviolet rays for 30 min. According to the characterization of the XRD, FESEM, and UV-visible, the polymeric medium gives a less granular size in addition to its ease of use and handling.
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T. Mohammed, Wadood, et Alyaa Kh. Mageed. « Extraction of Iron from Aqueous Chloride Media in Presence of Aluminum ». Iraqi Journal of Chemical and Petroleum Engineering 10, no 2 (30 juin 2009) : 27–36. http://dx.doi.org/10.31699/ijcpe.2009.2.5.

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The extraction of iron from aqueous chloride media in presence of aluminum was studied at different kinds of extractants(cyclohexanone, tributyl phosphate, diethyl ketone), different values of normality (pH of the feed solution), agitation time, agitation speed, operating temperature, phase ratio (O/A), iron concentration in the feed, and extractant concentration]. The stripping of iron from organic solutions was also studied at different values of normality (pH of the strip solution) and phase ratio (A/O). Atomic absorption spectrophotometer was used to measure the concentration of iron and aluminum in the aqueous phase throughout the experiments.The best values of extraction coefficient and stripping coefficient are obtained under the conditions of operation given in the table below: System Operation pH Agitation Time(min.) Agitation Speed(RPM) TemperatureoC Phase ratio Cyclohexanone conc. cyclohexanone exraction 1.5 10 400 30 3/1 50% stripping 1 10 400 30 3/1 50%
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Shuker M. Al-zubaidi, Zeena. « Volumetric and Viscometric studies of vitamin (B6) in aqueous and acidic media at different temperatures ». Al-Kufa University Journal for Biology 10, no 2 (18 septembre 2018) : 20–27. http://dx.doi.org/10.36320/ajb/v10.i2.8130.

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Densities and viscosities of pyridoxine(B6) in aqueous and acidic solutions at 298.15-313.15K have been measured. By Masson equation the experimental values of densities were used to estimate some significant parameters, such as apparent molal volume(Φv), limiting apparent molal volume(Φv0) and slop Sv, and the viscosity data have been investigatevia Jones-Dole equation, and the derived parameters, Jones-Dole coefficient B, and Falkenhagen coefficient A. The results were interpreted in term of solute-solute and solute –solvent interaction. The difference of B coefficient with temperature (dB/dT), was also determined the positive values indicate that pyridoxine(B6)in aqueous and acidic solutions is structure making.
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Rahman, Mashiur. « Relative reactivity of different monovalent alkalis on poly(ethylene terephthalate) geotextiles : Aqueous and alcoholic systems ». Journal of Industrial Textiles 44, no 3 (21 août 2013) : 373–97. http://dx.doi.org/10.1177/1528083713495247.

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The relative rate of degradation of poly(ethylene terephthalate) geotextiles in various monovalent alkali hydroxides was studied in both aqueous and alcoholic systems. In an aqueous system, the reaction of all three alkalis on poly(ethylene terephthalate) geotextiles is restricted to the surface since tenacity loss was insignificant and no surface cracks was noticed, whereas in an alcoholic system, significant loss in tenacity occurred due to the formation of surface crack. Furthermore, the relative rate of reactivity of metal hydroxides in aqueous and alkaline media was temperature dependent. However, in equimolar concentration, at 80℃, the relative rate in an aqueous system is of the following order: LiOH > NaOH > KOH in the ratio of 1.65:1.1:1.0. Above 80℃, the reaction is reversed, as aqueous KOH reacts faster than aqueous NaOH. Two different activation energies were found for aqueous KOH at a threshold temperature of 80℃. Furthermore, in heterogeneous systems using dimethyl terephthalate, aqueous KOH was slightly faster than aqueous NaOH in the temperature range of 70–80℃. In an alcoholic system, KOH is almost 1.5 times faster than NaOH at 20℃ and at 60℃.
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Wenyi, Tan, Fan Wenhui, Li Hongyi, Zhang Zixin et Zhu Yunkun. « Removal of Hg, As in FGD gypsum by different aqueous ammonia (amines) during CO2 sequestration ». Waste Management & ; Research : The Journal for a Sustainable Circular Economy 35, no 12 (26 octobre 2017) : 1296–301. http://dx.doi.org/10.1177/0734242x17733540.

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CO2 sequestration by flue gas desulfurization gypsum (FGDG) has become a promising FGDG disposal technology due to simultaneous CO2 emission reduction and FGDG conversion into calcium carbonate. In this paper, another merit of the novel technology, i.e., the removal of toxic elements (e.g., Hg and As) in FGDG, will be addressed for the first time. In three different aqueous ammonia (or amines) media, removal efficiencies of Hg and As in FGDG samples were evaluated during CO2 sequestration. Higher than 90% and 20% removal efficiencies, respectively, for Hg and As are achieved at 40°C in aqueous ammonia media, but they decrease at elevated temperatures. Ammonia loss takes place at 80°C and pH varies greatly with temperatures in aqueous ammonia. This is disadvantageous for the formation of Hg–ammonia complexes and for the yield of carbonates, which are responsible for Hg or As re-adsorption. The sequential chemical extraction method suggests that the speciation changes of Hg are induced by FGDG carbonation, and that unstable Hg speciation in triethanolamine increases at elevated temperatures.
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Cox, Robin A., et Erwin Buncel. « Three different mechanisms for azo-ether hydrolyses in aqueous acid ». Canadian Journal of Chemistry 90, no 10 (octobre 2012) : 791–97. http://dx.doi.org/10.1139/v2012-076.

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It has been shown recently that most ethers hydrolyze in aqueous acid media not by the traditional A1 or A2 process, but by a mechanism involving rate-determining proton transfer to the substrate, concerted with C–O bond cleavage. The reactions of azoethers are more complicated, because the azo group can be protonated in the acid reaction medium as well. This protonation has to be accounted for in the kinetic analysis. Often it simply ties up the substrate in an unreactive form; the hydrolysis reaction slows down as a result of the azo-protonated compound not being the reactant in the hydrolysis. However, there are other possibilities. If the ether group is suitably located in the substrate the azo-protonated compound can react with three water molecules (a “water wire”) in a fast reaction, and the alkoxy group is lost as a result. Depending on the acidity, in this mechanism either the initial three-water attack, or the breakup of the resulting intermediate, can be rate-determining, and both of these were observed. A third possibility is that ring protonation of suitable substrates can occur, giving delocalized carbocations that can form a hydrolysis product in subsequent fast reactions. Thus, three different hydrolysis mechanisms for azoethers in acidic media can be observed. Six azoethers were studied, one of which contained two methoxy groups. Both of these hydrolyzed, but by different mechanisms.
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Lönnemark, M., A. Magnusson et H. Ahlström. « Oral Contrast Media in CT of the Abdomen ». Acta Radiologica 34, no 5 (septembre 1993) : 517–19. http://dx.doi.org/10.1177/028418519303400519.

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In a double-blind randomized study 3 different preparations of oral contrast media for bowel opacification at CT of the abdomen have been compared. Plain aqueous solutions of amidotrizoate (9 mg I/ml) and iohexol (9 mg I/ml) were used as well as a preparation of iohexol (9 mg I/ml) to which a viscosity-increasing agent had been added. The distribution of the contrast media in the intestine, transit time and patient tolerance were evaluated. No significant differences were found regarding the distribution between the 3 preparations of contrast media, while there was a tendency for the transit time to be increased when the viscous preparation of iohexol was used. The aqueous solution of iohexol had the best taste, while the viscous preparation was markedly more difficult to drink. Aqueous solutions of iohexol and amidotrizoate were equal for bowel opacification and the addition of the viscosity-increasing agent did not improve the distribution of the contrast medium in the intestine.
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Reformatskaya, I. I., et A. N. Podobayev. « Corrosion Fatigue of Copper in Aqueous Media ». Occupational Safety in Industry, no 3 (mars 2023) : 22–26. http://dx.doi.org/10.24000/0409-2961-2023-3-22-26.

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The failure of the cooling systems of engines and propellers of the ship poses the serious hazard to passengers and crew. Damage to these units is often caused by corrosion, with localized corrosion being the most dangerous. In the case under consideration, when the metal is simultaneously affected by a corrosive environment and alternating mechanical loads, conditions arise for the behaviour (occurrence) of corrosion fatigue. The prospects of cathodic electrochemical protection of these units are considered in the paper. Since the cooling systems and propellers are made of copper alloys, the effect was studied concerning the potential and composition of the solution on the corrosion of the main component of the structural material — copper. Copper samples with a smooth mechanical pressure concentrator cantilevered in a fluoroplastic electrochemical cell were tested. Alternating bending loads were applied to them, and the number of load cycles before the destruction of the sample (durability) was determined. The experiments were carried out in deaerated solutions of the surfactantly inactive electrolyte NaF, as well as fluoride solutions with additives of surfactants and organic surfactants - benzotriazole. At the same time, an interval of potentials was set, in which the only Faraday process is possible — the reduction of traces of dissolved oxygen. It was found that at potentials less than the zero charge potential, the durability of copper increases significantly. And the introduction of chloride ions and benzotriazole into the solution, on the contrary, leads to a strong decrease in its durability. The potential of zero charge of copper was determined from the measurement data of the differential capacitance of the metal in sodium fluoride solutions with different concentrations of fluoride. The increase in the durability of the metal is explained by the occurrence of hydrogen bonds between the water molecules adsorbed by the hydrogen atoms. This manifests the so-called negative Rebinder effect. For electrochemical protection, the potential range is recommended below the potential of zero charge of the metal, but above the potential of water decomposition. For cooling systems, it is recommended to use deionized water as a coolant.
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Müller, B., K. Franze et D. Mebarek. « Corrosion Inhibition of Aluminum Pigments in Aqueous Alkaline Media at Different pH Values ». CORROSION 51, no 8 (août 1995) : 625–30. http://dx.doi.org/10.5006/1.3293623.

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De Stefano, Concetta, Antonio Gianguzza, Daniela Piazzese et Silvio Sammartano. « Polyacrylate Protonation in Various Aqueous Ionic Media at Different Temperatures and Ionic Strengths ». Journal of Chemical & ; Engineering Data 45, no 5 (septembre 2000) : 876–81. http://dx.doi.org/10.1021/je0000219.

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El‐Hefny, N. E., et J. A. Daoud. « Extraction of Copper(II) by CYANEX 302 in Kerosene from Different Aqueous Media ». Solvent Extraction and Ion Exchange 25, no 6 (octobre 2007) : 831–43. http://dx.doi.org/10.1080/07366290701634172.

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Cheema, Mohammad Arif, Mohammad Siddiq, Silvia Barbosa, Pablo Taboada et Víctor Mosquera. « Surface and Bulk Properties of Two Amphiphilic Phenothiazine Drugs in Different Aqueous Media ». Journal of Chemical & ; Engineering Data 53, no 2 (février 2008) : 368–73. http://dx.doi.org/10.1021/je7003963.

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41

Naumov, Vladimir S., et Stanislav K. Ignatov. « Dissolution of chitosan nanocrystals in aqueous media of different acidity. Molecular dynamic study ». Carbohydrate Polymers 207 (mars 2019) : 619–27. http://dx.doi.org/10.1016/j.carbpol.2018.12.019.

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42

Hategan, A., A. Popescu, C. Butan, C. Oproiu, D. Hategan et V. V. Morariu. « High energy electron beam inactivation of lactate dehydrogenase suspended in different aqueous media ». Czechoslovak Journal of Physics 49, S1 (janvier 1999) : 535–40. http://dx.doi.org/10.1007/s10582-999-0072-x.

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43

Nemtoi, Gheorghe, Florica Ionica, Tudor Lupascu et Alexandru Cecal. « Voltammetric Characterization of the Iron Behaviour from Steels in Different Electrolytic Media ». Chemistry Journal of Moldova 5, no 1 (juin 2010) : 98–105. http://dx.doi.org/10.19261/cjm.2010.05(1).10.

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The dissolution of the iron from steel was observed by drawing the cyclic voltammetry (CV) for the systems consisting of the solution resulted when the alloy sample was immersed in HNO3, H2SO4, and HCl, aqueous solutions on platinum disk electrode (PtDE). The presence of some redox processes can be observed only in HNO3 which confirms the complexity of the mechanism of Fe dissolution in this acid. On the other hand, there were manufactured electrodes of steel samples taken into experiment achieving the corrosion characteristics in the media mentioned above.
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44

Nemtoi, Gh, Ig Cretescu, Iuliana Breaban, P. C. Verestiuc et Oana-Maria Tucaliuc. « Voltammetric characterization of Hg2+ ion behaviour in acid media on different electrodes ». Acta Chemica Iasi 22, no 2 (1 décembre 2014) : 135–44. http://dx.doi.org/10.2478/achi-2014-0011.

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Abstract This article presents some aspects related to the cathodic discharge of the mercuric ion provided from HgCl2 into an aqueous solution of 0.1 M H2SO4 on different types of electrodes: gold disc electrode (GDE), carbon paste electrode (CPE) and platinum-disk electrode (PDE). Using the rotating disk electrode technique applied on PDE it was established that the cathodic discharge mechanism for the mercuric ion is based on both process types: mass transport, achieved by diffusion and charge transfer, achieved by electron transfer from cathode to mercury ion
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Lazaro, Gilderman Silva, Silmara Caldas Santos, Luiz Eduardo Almeida, Ledjane Silva Barreto et Euler Araujo dos Santos. « The Equilibrium between Calcite and Apatite Precipitation onto Bioglass from Three Different Aqueous Media ». Key Engineering Materials 493-494 (octobre 2011) : 102–7. http://dx.doi.org/10.4028/www.scientific.net/kem.493-494.102.

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It has been reported that there is a slight equilibrium between calcite and apatite precipitation from SBF solution during typical bioactivity assays, once it is supersaturating in both ionic precursors. In order to better understand this mechanism, we have proposed here to evaluate the role of three different aqueous medium (water, SBF and McCoy), under equilibrium (agitation) and out of equilibrium (no agitation).
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46

Kaldre, Dainis, Fabrice Gallou, Christof Sparr et Michael Parmentier. « Interface-rich Aqueous Systems for Sustainable Chemical Synthesis ». CHIMIA International Journal for Chemistry 73, no 9 (18 septembre 2019) : 714–19. http://dx.doi.org/10.2533/chimia.2019.714.

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Mimicking an enzyme's exquisite activity and selectivity is a long-standing goal for sustainable chemical method development in aqueous media. The use of interface-rich aqueous systems, such as single-chain polymers, micelles and vesicle membranes recently emerged as strategy to emulate the compartmentalization of natural systems. In aqueous solution, aggregates such as micelles or microemulsion droplets are formed, providing reaction environments different from bulk solutions that frequently improve selectivity and accelerate reaction rates for a wide array of chemical transformations. We present here selected examples of interface-rich aqueous systems and discuss the advantages they offer for chemical synthesis. In particular metal-catalyzed cross-coupling reactions are highlighted and future challenges to perform reactions in interface-rich aqueous media are discussed.
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47

Paliwal, Pradeep, Srinivasa Rao Jetti, Anjna Bhatewara, Tanuja Kadre et Shubha Jain. « DABCO Catalyzed Synthesis of Xanthene Derivatives in Aqueous Media ». ISRN Organic Chemistry 2013 (18 mars 2013) : 1–6. http://dx.doi.org/10.1155/2013/526173.

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The reaction of 5,5-dimethylcyclohexane-1,3-dione with various heteroarylaldehydes afforded the corresponding heteroaryl substituted xanthene derivatives 1(a–f). The reaction proceeds via the initial Knoevenagel, subsequent Michael, and final heterocyclization reactions using 1,4-diazabicyclo[2.2.2]octane (DABCO) as a catalyst in aqueous media. The synthesized heteroaryl substituted xanthenes 1(a–f) reacted with malononitrile to obtain different alkylidenes 2(a–f). Short reaction time, environmentally friendly procedure, avoiding of cumbersome apparatus, and excellent yields are the main advantages of this procedure which makes it more economic than the other conventional methods.
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Maniam, Kranthi Kumar, et Shiladitya Paul. « Corrosion Performance of Electrodeposited Zinc and Zinc-Alloy Coatings in Marine Environment ». Corrosion and Materials Degradation 2, no 2 (21 avril 2021) : 163–89. http://dx.doi.org/10.3390/cmd2020010.

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Electrodeposited zinc and zinc-alloy coatings have been extensively used in a wide variety of applications such as transport, automotive, marine, and aerospace owing to their good corrosion resistance and the potential to be economically competitive. As a consequence, these coatings have become the industry choice for many applications to protect carbon and low alloy steels against degradation upon their exposure in different corrosive environments such as industrial, marine, coastal, etc. Significant works on the electrodeposition of Zn, Zn-alloys and their composites from conventional chloride, sulfate, aqueous and non-aqueous electrolyte media have been progressed over the past decade. This paper provides a review covering the corrosion performance of the electrodeposited Zn, Zn-alloy and composite with different coating properties that have been developed over the past decade employing low-toxic aqueous and halide-free non-aqueous electrolyte media. The influence of additives, nano-particle addition to the electrolyte media on the morphology, texture in relation to the corrosion performance of coatings with additional functionalities are reviewed in detail. In addition, the review covers the recent developments along with cost considerations and the future scope of Zn and Zn-alloy coatings.
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Xu, Zhou-Qing, Xian-Jie Mao, Yuan Wang, Wei-Na Wu, Pan-Dong Mao, Xiao-Lei Zhao, Yun-Chang Fan et Hui-Jun Li. « Rhodamine 6G hydrazone with coumarin unit : a novel single-molecule multianalyte (Cu2+ and Hg2+) sensor at different pH value ». RSC Advances 7, no 67 (2017) : 42312–19. http://dx.doi.org/10.1039/c7ra05424f.

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An effective colourimetric and ratiometric fluorescent probe for Cu2+ in neutral aqueous media was synthesised. Moreover, the probe could sense Hg2+ with fluorescence enhancement at high pH.
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50

Domínguez de María, Pablo, Selin Kara et Fabrice Gallou. « Biocatalysis in Water or in Non-Conventional Media ? Adding the CO2 Production for the Debate ». Molecules 28, no 18 (6 septembre 2023) : 6452. http://dx.doi.org/10.3390/molecules28186452.

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Biocatalysis can be applied in aqueous media and in different non-aqueous solutions (non-conventional media). Water is a safe solvent, yet many synthesis-wise interesting substrates cannot be dissolved in aqueous solutions, and thus low concentrations are often applied. Conversely, non-conventional media may enable higher substrate loadings but at the cost of using (fossil-based) organic solvents. This paper determines the CO2 production—expressed as kg CO2·kg product−1—of generic biotransformations in water and non-conventional media, assessing both the upstream and the downstream. The key to reaching a diminished environmental footprint is the type of wastewater treatment to be implemented. If the used chemicals enable a conventional (mild) wastewater treatment, the production of CO2 is limited. If other (pre)treatments for the wastewater are needed to eliminate hazardous chemicals and solvents, higher environmental impacts can be expected (based on CO2 production). Water media for biocatalysis are more sustainable during the upstream unit—the biocatalytic step—than non-conventional systems. However, processes with aqueous media often need to incorporate extractive solvents during the downstream processing. Both strategies result in comparable CO2 production if extractive solvents are recycled at least 1–2 times. Under these conditions, a generic industrial biotransformation at 100 g L−1 loading would produce 15–25 kg CO2·kg product−1 regardless of the applied media.
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