Дисертації з теми "Synergistic mixtures of surfactants"
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Левченко, Сергій Володимирович. "Синергічні композиції інгібіторів корозії і поверхнево-активних речовин для процесів обробки сталі". Doctoral thesis, Київ, 2020. https://ela.kpi.ua/handle/123456789/38885.
Повний текст джерелаДана робота присвячена розробці технологічних рідин на основі створення синергічних сумішей інгібіторів корозії і ПАР для електроіскрового механічного методу підготовки сталевих поверхонь за допомогою електричних шліфувальних машин. Антикорозійна ефективність синергічних сумішей пасиваторів оксидної і сольової дії залежить від природи компонентів, механізму їх дії, а також від співвідношення молярних концентрацій складових в синергічних сумішах. Результати поляризаційних досліджень електрохімічної поведінки сталі показали перевагу інгібуючої ефективності синергічних композиції порівняно з ефективністю окремих компонентів, що підтверджується наявністю зони пасивації в широкому діапазоні потенціалів (0,8-1 В) і мінімального значення густини струму повної пасивації (1-2*10^-6 А/см^2), що свідчить про повний захист сталі від корозії. Показано, що зниження поверхневого натягу водних розчинів створених сумішей ПАР на межі повітря - рідина і зниження мікротвердості сталі на межі рідина-метал мають подібний характер. Введення розроблених технологічних рідин в зону обробки дозволяє знизити енергетичні витрати процесу на 30-40%, і підвищити клас чистоти поверхні на 3 і більше одиниць за рахунок ефекту пластифікації поверхні (ефект Ребіндера). Електроіскрова обробка оцинкованою щіткою дозволяє наносити на поверхню металу цинкові протектори, які разом з синергічними сумішами інгібіторів виявляють явище нададитивності, забезпечують майже стовідсотковий антикорозійний захист сталі навіть в сильно агресивних середовищах (3% NaCl), і збільшує період післяопераційного зберігання. Особливо високі показники захисту сталевих поверхонь отримано при використанні оцинкованої щітки з наступним нанесенням лакофарбового покриття, де реалізуються ефект взаємного посилення (синергізму) між протекторним електрохімічним захистом з лакофарбовим покриттям.
Левченко, Сергій Володимирович. "Синергічні композиції інгібіторів корозії і поверхнево-активних речовин для процесів обробки сталі". Thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/38505.
Повний текст джерелаДана робота присвячена розробці технологічних рідин на основі створення синергічних сумішей інгібіторів корозії і ПАР для електроіскрового механічного методу підготовки сталевих поверхонь за допомогою електричних шліфувальних машин. Антикорозійна ефективність синергічних сумішей пасиваторів оксидної і сольової дії залежить від природи компонентів, механізму їх дії, а також від співвідношення молярних концентрацій складових в синергічних сумішах. Результати поляризаційних досліджень електрохімічної поведінки сталі показали перевагу інгібуючої ефективності синергічних композиції порівняно з ефективністю окремих компонентів, що підтверджується наявністю зони пасивації в широкому діапазоні потенціалів (0,8-1 В) і мінімального значення густини струму повної пасивації (1-2*10^-6 А/см^2), що свідчить про повний захист сталі від корозії. Показано, що зниження поверхневого натягу водних розчинів створених сумішей ПАР на межі повітря - рідина і зниження мікротвердості сталі на межі рідина-метал мають подібний характер. Введення розроблених технологічних рідин в зону обробки дозволяє знизити енергетичні витрати процесу на 30-40%, і підвищити клас чистоти поверхні на 3 і більше одиниць за рахунок ефекту пластифікації поверхні (ефект Ребіндера). Електроіскрова обробка оцинкованою щіткою дозволяє наносити на поверхню металу цинкові протектори, які разом з синергічними сумішами інгібіторів виявляють явище нададитивності, забезпечують майже стовідсотковий антикорозійний захист сталі навіть в сильно агресивних середовищах (3% NaCl), і збільшує період післяопераційного зберігання. Особливо високі показники захисту сталевих поверхонь отримано при використанні оцинкованої щітки з наступним нанесенням лакофарбового покриття, де реалізуються ефект взаємного посилення (синергізму) між протекторним електрохімічним захистом з лакофарбовим покриттям.
The work is devoted to the development of process fluids based on synergistic mixtures of surfactants and corrosion inhibitors for the electric-spark mechanical method steel surfaces preparing using electric grinders. The use of individual representatives of inhibitors and surfactants usually does not allow to obtain high efficacy. More effective are mixtures, the composition of which is characterized by a synergism in the action of their components. Nowadays, studies devoted to elucidating the mechanism of action of highly effective synergistic mixtures of metal corrosion inhibitors and surfactant compositions, same as related to the uncertainty of if effectiveness influence on the nature of components, as well as concerning the ratio of their concentrations in solutions remain developed insufficiently. The influence of additives on the qualitative characteristics of the prepared surfaces and energy costs of the process are also studied insufficiently. Such situation requires to develop research aimed on the increasing the corrosion resistance of metals during their postoperative period of storage, and also on improving of its protective properties after the paints and varnishes application. To prevent an occurrence of corrosion processes during electrospark machining of steel, technological fluids specifically containing synergistic mixtures of corrosion inhibitors with different mechanism of action oxide and salt passivation or adsorption were developed, their effectiveness depends on the ratio of components and is characterized by an extremum where attained maximum level of inhibitory effect of additives on the kinetics of electrochemical corrosion processes of steel and full protection is achieved. Anticorrosive efficiency of synergistic mixtures of the passivator oxide action (sodium nitrite) and the salt action (sodium silicate) depend on the nature of the components, the mechanism of their action, and also on the ratio of its molar concentrations constituting in synergistic mixtures and is characterized by a synergistic extremum of inhibitory action at a ratio of sodium nitrite concentrations and sodium silicate, as 1:2. The results of polarization studies of the electrochemical behavior of steel have revealed an advantage of the inhibitory efficiency of the synergistic compositions compared to the efficiency of individual components, and is confirmed by the existence of a passivation zone in a wide range of potentials (0.8-1 V) and by minimum values of the full passivation (1-2*10^-6 A/cm^2) current density, which indicates the comprehensive corrosion protection of steel. The introduction of such process fluids into the processing zone allows the treatment energy costs reducing by 30–40% and increasing the surface cleanliness class by 3 and more units due to the surface plasticization effect (Rehbinder effect). Synergistic mixtures of surfactants contain molecules with oppositely charged functional groups, between which the forces of mutual attraction arise that allows to achieve high surface activity at the phase boundaries: air - liquid and liquid - metal. It was found that a decrease of the surface tension in aqueous solutions of the developed surfactant mixtures at the air-liquid interface and a decrease in the microhardness of steel at the liquid-metal interface have a similar nature and demonstrate efficiency extremes with a similar ratio of molar concentrations of anionic and cationic active components of order 1:1. The thermodynamic characteristics of the formation of an adsorption layer surfactant at the interface of the aqueous solution-air were determined. It is shown that the dependences of surface tension, changes in entropy and enthalpy on the ratio of molar concentrations of cationic and anion active surfactants have a parallel extreme character, and the positive value of ΔS> 0 indicates that the driving force of the direct adsorption process is the entropy factor. The electro-spark treatment with a galvanized brush allows to apply zinc protectors to the metal surface, which, together with the synergistic mixtures of inhibitors, demonstrate the phenomenon of additivity and provide almost one hundred percent corrosion protection of steel even in strong corrosive media (3% NaCl), and enlarges the period of postoperative storage. Especially high rates of steel surfaces protection are obtained using a galvanized brush with the subsequent application of a paint and varnish coating, where the effect of mutual reinforcement (synergism) between the sacrificial electrochemical protection with a paint coating is realized. Due to the formation of zinc hydroxide inside the paint coating, the ohmic resistance is enlarged, the adhesion and protective properties of paint coatings are improved.
Hines, J. D. "Investigation of surfactants and surfactant mixtures." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337736.
Повний текст джерелаMonast, Patrick. "Wetting behavior of ternary mixtures containing surfactants." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ64410.pdf.
Повний текст джерелаStellner, Kevin Lance. "Precipitation of surfactants and surfactant mixtures in aqueous solutions /." Full-text version available from OU Domain via ProQuest Digital Dissertations, 1987.
Знайти повний текст джерелаLaradji, Mohamed. "Ternary mixtures of water, oil and surfactants : equilibrium and dynamics." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39483.
Повний текст джерелаFurthermore, we have studied the effects of surfactants on the dynamics of phase separation of two immiscible fluids, and found a drastic alteration in the kinetics. In particular, we found that surfactants slow down the growth to a non-algebraic one leading eventually to a microphase separation.
Mirkin, Roy John. "The phase behaviour of polyoxyethylene, surfactants, phospholipids, and their mixtures." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332777.
Повний текст джерелаVries, Filicity Ann. "Synergistic effects of mixtures of fungicides and medicinal plant extracts against Botrytis cinerea." Thesis, University of the Western Cape, 2008. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_6798_1372423235.
Повний текст джерелаWe hypothesize that South African medicinal plants contain compounds that can act in synergism with synthetic antifungal compounds. Four fungicides - Sporekill&trade
, Rovral&trade
, Terminator&trade
and Teldor&trade
at doses 0.1, 0.2, 0.4 and 0.8 mL L-1 and plant species Galenia africana, Elytropappus rhinocerotis and Tulbaghia violacea were tested aloneand in different combinations for their potency (efficacy) on radial growth inhibition of Botrytis cinerea strains on potato dextrose plates. Four doses of plant extract for each of the respective plant species were used. A total of 48 combinations were tested for each strain. Mixtures of plant extracts were far more effective in controlling strains compared to the individual components alone, representing significant levels of in vitro synergistic interactions. Combinations of these components represent an attractive future prospect for the development of new management strategies for controlling B. cinerea. Since the in vitro tests of these mixtures showed inhibitory activity, the mixtures were tested for activity in assays on Granny Smith apples. In vitro tests can be used to screen mixtures to obtain information on their inhibitory activity on a pathogen, however, the environmental conditions of the fruit and the ability of the pathogen to grow into the fruit cannot be simulated in vivo. A series of two-fold doses of medicinal plant extracts were combined with fungicides to conduct decay inhibition studies. The incidence of gray mold was significantly reduced by mixtures of plant extracts and fungicides. Under conditions similar to those in commercial storage, a drench treatment with G. africana and Rovral&trade
significantly (p=0.05) inhibit gray mold on the apples and was more effective than the plant extract and fungicide alone. The treatments exerted synergistic effects and were markedly better than the components applied alone. The wound colonization assay was used for optimal decay control. In a drench, much higher volumes of the treatments are used to ensure that the components of the suspension are deposited evenly over the entire fruit surface. Drenching of fruit to apply other chemicals is an established practise in the pome (fleshy) fruit industry, and simplifies the commercial application of the mixtures, as no additional infrastructure at commercial packing houses will be required. This approach not only makes it possible to reduce fungicide concentrations while maintaining adequate decay control, but also ensures a reduction of the chemical residue on the fruit.
Cookey, Grace Agbizu. "Interactions of binary mixtures of ionic and non-ionic surfactants in aqueous solution." Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619452.
Повний текст джерелаVan, Gelder Richard N. M. R. "Structuro-kinetic studies of the crystallisation of straight chain surfactants and homologues mixtures." Thesis, University of Strathclyde, 1998. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25998.
Повний текст джерелаHazzaa, M. I. "Synergistic effects in the inhibition by chromate-containing mixtures of the corrosion of mild steel." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380533.
Повний текст джерелаAbdel-Rahem, Rami. "Phase behavior and structural transitions in the mixtures of cationic surfactants and hydrophobic counterions." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969146299.
Повний текст джерелаGoldsipe, Arthur Clayton. "Molecular-thermodynamic theories of micellization of multicomponent surfactant mixtures and of pH-sensitive surfactants." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34277.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 249-264).
This thesis focuses on two research areas that are particularly relevant to the practical application of surfactant science: (1) the micellization of multicomponent surfactant mixtures, and (2) the micellization of pH-sensitive (or amphoteric) surfactants. Surfactant formulations of practical utility typically consist of many surfactant components. In many practical applications, pH-sensitive surfactants are added as a secondary surfactant because they enhance performance properties, including solubility, foaming, and mildness to the skin or to the eyes. In addition, pH-sensitive surfactants may be used eectively in novel applications where pH variations can be utilized to control self-assembly, including controlled drug release, targeted gene delivery, and the fabrication of nanoscale materials for optics, electronics, and sensors. First, a molecular-thermodynamic (MT) theory was developed to account for counterion binding to mixed micelles composed of ionic-nonionic and ionic-zwitterionic binary surfactant mixtures. The theory successfully predicted the degree of counterion binding ([beta]) of monovalent and multivalent ions to mixed micelles as a function of the micelle composition ([alpha]).
(cont.) The theory was also found to be consistent with the concept of critical counterion binding. An inection in the [beta vs. [alpha] curve was correlated to a micelle shape transition. Second, the MT theory was generalized to include pH eects in order to model the micellization of pH-sensitive surfactants. The theory was validated by comparing predictions of critical micelle concentrations (cmc's), micelle aggregation numbers, and micellar titration behavior to experimental data for alkyldimethylamine oxide surfactants, which are cationic in the protonated state (at low pH) and zwitterionic in the deprotonated state (at high pH). The MT theory qualitatively reproduced the minimum in the cmc and the maximum in the micelle aggregation number, which are both observed experimentally at intermediate pH values, resulting from the synergy between the two forms of the pH-sensitive surfactant in the micelle. This self-synergy, which was previously attributed by other researchers to the formation ofsurfactant-surfactant hydrogen bonds in the micelle, was rationalized instead in terms of electrostatic interactions operating between surfactants and bound counterions in the micelle. Very good quantitative agreement was obtained for the predicted cmc's in solutions containing no added salt.
(cont.) In particular, the experimentally observed maximum in the cmc, which originated from changes in the solution ionic strength, was reproduced by the MT theory but not by the empirical regular solution theory (RST). Micellar titration data were also examined in terms of the relative values of the micellar deprotonation equilibrium parameter (pK). The pK was related to the derivative of the electrostatic contribution to the free energy of micellization ( gelec) with respect to . The molecular model of gelec predicted pK > 0 in the limit of micelles composed entirely of the deprotonated form of the pH-sensitive surfactant, consistent with the experimental data. Third, a theory based on RST was developed to model the titration behavior of micelles containing a pH-sensitive surfactant and an arbitrary number of conventional surfactants. The conventional surfactants were successfully modeled as a single eective surfactant, thus considerably simplifying the theoretical analysis of multicomponent surfactant mixtures. The RST description was validated using experimental micellar titration data for single surfactant systems (obtained from the literature) and for binary surfactant mixtures (measured as part of this thesis).
(cont.) Experimental uncertainties in the micellar titration data were examined, and a new method was introduced to account for these uncertainties by using a weighted regression analysis. Fourth, a MT theory was developed to model the micellization of mixtures containing an arbitrary number of conventional surfactants. The maximum micelle radius was examined theoretically for a ternary surfactant mixture. Due to the limited availability of experimental data, only the predicted cmc's were compared with the experimental cmc's. Good agreement was obtained for the predicted cmc's, which were comparable to, and sometimes better than, the cmc's determined using RST. The MT theory was also used to model a commercial nonionic surfactant (Genapol UD-079), which was modeled as a mixture of 16 surfactant components. The predicted cmc agreed remarkably well with the experimental cmc. The monomer concentration was predicted to increase signicantly above the cmc. In addition, the monomer and the micelle compositions were predicted to vary signicantly with surfactant concentration. These composition variations were rationalized in terms of competing steric and entropic eects and a micelle shape transition near the cmc.
(cont.) Finally, the MT theory was further generalized to model the micellization behavior of mixtures of a pH-sensitive surfactant and an arbitrary number of conventional surfactants. Predicted values of the solution pH of mixtures of a pH-sensitive surfactant and an ionic surfactant, as well as of the cmc's of mixtures of two pH-sensitive surfactants, compared favorably with the experimental values. The MT theory was also validated using micellar titration data for varying compositions of mixed micelles containing dodecyldimethylamine oxide (C12DAO) and a cationic, nonionic, or anionic surfactant. The MT theory accurately modeled the titration behavior of C12DAO mixed with the nonionic surfactant. However, C12DAO appeared to interact more favorably with the anionic and the cationic surfactants than waspredicted by the MT theory. The MT theories presented in this thesis represent the rst molecular-based models of the micellization behavior of the following systems: (1) pH-sensitive surfactants, (2) mixtures of three or more conventional surfactants, and (3) mixtures of pH-sensitive surfactants and conventional surfactants. The MT theories resulted in qualitative and quantitative predictions of the micellization properties for a variety of surfactant systems.
(cont.) A simpler theory based on RST was also developed to model titrations of micelles containing pH-sensitive and conventional surfactants. In addition, this thesis resulted in the rst experimental study of the eect of micelle composition on the titration behavior of mixed micelles containing a pH-sensitive surfactant and a conventional surfactant. The resulting MT theories have provided fundamental, physical insight, and they may also decrease the need for the costly and time-consuming process associated with "trial-and-error" surfactant formulation.
by Arthur Clayton Goldsipe.
Ph.D.
Khouryieh, Hanna Anton Michael. "Rheological characterization of Xanthan-guar mixtures in dilute solutions." Diss., Manhattan, Kan. : Kansas State University, 2006. http://hdl.handle.net/2097/208.
Повний текст джерелаZamlynny, Volodymyr. "Electrochemical studies of adsorption of insoluble pyridine surfactants and their mixtures at a gold(111) electrode." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ33292.pdf.
Повний текст джерелаDave, Hiteshkumar Rajeshkumar. "Self Assembly In Aqueous And Non-aqueous Sugar-Oil Mixtures." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1229737030.
Повний текст джерелаJayawardane, D. "Investigating the adsorption and surface active behaviour of silk fibroin peptides and mixtures of peptide and conventional surfactants." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/17685/.
Повний текст джерелаChiappisi, Leonardo [Verfasser], Michael [Akademischer Betreuer] Gradzielski, and Giuseppe [Akademischer Betreuer] Lazzara. "Ionic co-assembly in mixtures of polysaccharides and surfactants / Leonardo Chiappisi. Gutachter: Michael Gradzielski ; Giuseppe Lazzara. Betreuer: Michael Gradzielski." Berlin : Technische Universität Berlin, 2015. http://d-nb.info/1072684136/34.
Повний текст джерелаKnowles, Cindy-Lee. "Synergistic effects of mixtures of the kresoxim-methyl fungicide and medicinal plants extracts in vitro and in vivo against Botrytis Cinerea." Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
Повний текст джерелаSkoglund, Sara. "Self-assembly in mixtures of an anionic and a cationic surfactant: A comparison between static light scattering and cryotransmission electron microscopy." Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34032.
Повний текст джерелаLukowicz, Thomas. "Synergistic solubilisation of fragrances in binary surfactant systems and prediction of their EACN value with COSMO-RS." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10090/document.
Повний текст джерелаSolvo-surfactants are a relatively new class of amphiphiles, which exhibit properties of both, surfactants and solvents. They are able to form aggregates, wherein they can solubilise hydrophobic compounds. Furthermore they exhibit volatile characteristics, which make them interesting for applications where volatility is a key factor, such as aqueous fragrance solubilisations. In a solvo-surfactant/oil/water (SOW) system, the phase behaviour is strongly influenced by the hydrophobicity of the oil. Therefore the equivalent alkane carbon number (EACN) of several polar oils, such as dialkylethers, 2-alkanones, 1-chloroalkanes etc. was determined and the decrease in EACN with respect to n-alkanes was related to its functionalization, as well as rationalised with the effective packing parameter for each corresponding type of oil. The EACN of all 94 oils were then used in a multilinear regression analysis, based on COSMO-RS -moments, in order to establish a QSPR model, which is able to predict the EACN of any hydrocarbon oil. The influence of ionic surfactants was finally investigated in a SOW system, with various oils of different EACN. It was found that the ionic surfactant increases strongly the temperature stability of the (pseudo-)ternary system, as well as the efficiency to solubilise the oil. However the efficiency undergoes a maximum for a certain molar fraction of ionic surfactant, since the latter prevents the system to inverse. Thus a bicontinuous microemulsion cannot be formed, which is known to solubilise high amounts of oil and water
Vieira, JoseÌlio. "Properties of aqueous solutions of triblock coploymers of ethylene oxide and propylene oxide and their mixtures with surfactants studies by surface tension and neutron reflection." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270181.
Повний текст джерелаViera, Josélio. "Properties of aqueous solutions of triblock copolymers of ethylene oxide and propylene oxide and their mixtures with surfactants studied by surface tension and neutron reflection." Thesis, University of Oxford, 2002. http://ora.ox.ac.uk/objects/uuid:b37a66d2-8384-4dee-b9bb-60f6e3d5b3c3.
Повний текст джерелаSousa, Bruno Abdon Inácio de. "Avaliação toxicológica de misturas dos medicamentos veterinários (Monensina, Sulfametazina e Enrofloxacina) em Daphnia magna (Cladocera, Crustacea)." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-28012014-160019/.
Повний текст джерелаThis work aims to study the acute and chronic toxicity of the isolated and binary mixtures action of three veterinary drugs (Monensin, Sulfamethazine and Enrofloxacin) for the test organism Daphnia magna. The determined acute toxicity of enrofloxacin was EC50 - 54.36 mgL-1, monensin EC50 - 15.11 mgL-1 and sulfamethazine EC50 - 183.80 mgL-1. In the chronic toxicity tests were determined 3 endpoints (survival, reproduction and adult size) and the LOEC determined for enrofloxacina was 0.33 mgL-1, monensin 0.09 mgL-1 and sulfamethazine 6.8 mgL-1. To make a comparison between the tests of isolated substances and binary mixtures it was used the concept of toxic unit (TU), this comparison was made by adding the UT of individual studies and comparing the test results of mixtures to determine whether there was a synergistic action, additive or antagonistic. The acute mixture assay monensin/enrofloxacin showed synergistic action yet the assays monensin/sulfamethazine and sulfamethazine/enrofloxacin showed antagonistic action. The chronic mixing assays monensin / enrofloxacin and monensin / sulfamethazine showed synergistic action, but were not dose-dependent and testing sulfamethazine / enrofloxacin present antagonistic action. Based on this study it can be concluded that the mixing of these drugs interferes with its toxicity, and may cause synergistic or antagonistic effect
Khalili, Imad. "Sensibilité, sévérité et spécificités des explosions de mélanges hybrides gaz/vapeurs/poussières." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0088/document.
Повний текст джерелаThe explosion sensitivity and severity of various gas/vapor-dust mixtures have been studied thanks to specifically modified apparatuses based on a 20 L sphere and a Hartmann tube. The specificities of gas/dust hybrid mixtures explosions have been highlighted. In fact, even for gas concentrations lower than the lower explosivity limit (LEL), the ignition probability and the explosion severity can be greatly increased, which will notably lead to great changes in the Ex zones determination. For instance, it has been shown that such mixtures can be explosive when both the dust and gas concentrations are below their respective minimum explosive concentration and LEL. Moreover, synergistic effects have been observed and the rate of pressure rise of hybrid mixtures can be greater than those of the pure gases themselves. The origins of these specificities should not be sought in the modification of a single parameter, but could probably be attributed to combined impacts on hydrodynamics (flame propagation), thermal transfer and combustion kinetics. Experiments have been carried out in order to underline the significance of each contribution. Based on classical shrinking core models taking into account the various limitations during a non-catalytic gas/solid reaction and on homogeneous combustion for gases, a model has been developed to represent the time evolution of the explosion pressure for such mixtures
Kadi, Mari. "Bilayers with Surfactant-induced Pores and Demixing in Micelles : Studies of Segregation in Amphiphile Systems." Doctoral thesis, Uppsala University, Department of Physical Chemistry, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3565.
Повний текст джерелаThe focus of this thesis has been on the effects of segregation in mixtures of amphiphilic molecules. Two different systems were investigated: fluorocarbon-hydrocarbon surfactant mixtures and lipid-surfactant mixtures.
In fluorocarbon-hydrocarbon surfactant mixtures the repulsive interactions between the chains can lead to a demixing into different types of coexisting micelles, fluorocarbon rich and hydrocarbon rich. From NMR self-diffusion measurements such a demixing was found to occur in the mixture of the partially fluorinated surfactant HFDePC and C16TAC. We furthermore suggested a demixing also within the micelles to explain 19F-NMR line width data and results from neutron scattering.
In lipid-surfactant mixtures, a segregation of the molecules may instead be caused by a difference in the preferred curvature of the lipid and the surfactant residing within the same aggregate. Using a surfactant selective electrode, binding isoterms of four different cationic surfactants (C12TAC, C14TAC, C16TAC and HFDePC) to preformed lipid (GMO) vesicles were determined. Perforated vesicles were observed by cryo-TEM in the mixture with C16TAC. To explain the results from the binding isoterms, the formation of pores in the bilayer was regarded as a cooperative process, similar to micelle formation. The surfactant accumulates at the edges of the pores, and increasing the surfactant concentration results in an increased number of pores with a constant surfactant/lipid ratio at the edges.
The lipid-surfactant mixtures were also studied at the solid/solution interface using AFM. An adsorbed mesh structure, a counterpart to the bulk perforated lamellar phase, was observed for the first time.
Sato, Bruno Maiko. "Síntese e propriedades de líquidos iônicos e tensoativos." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-03092012-141515/.
Повний текст джерелаThe developed work focused the study of the solvation of binary mixtures among water and ionic liquids, ILs. Highlighting the influence of the lipophilicity and structure of the ILs. Moreover, it was studied a new series of surface active ionic liquids, SAILs, and the properties of these SAILs in water, was studied using many experimental techniques. The ILs study started with the synthesis, purification and characterization of the 1-allil-3-alkylimidazolium chlorides, and after, it was studied the solvation of the aqueous binary mixtures. In this study, they were utilized solvatochromic probes, these substances are sensitive to the medium properties, and can be analyzed using the Uv-Vis spectroscopy. In order to explain the obtained results, it was applied a solvation model, developed by the research group. This model describes the solvation considering the presence of the two solvents and a “:complex” water-IL. The solvatochromic study was utilized three probes, MePMBr2, OcPMBr2 e MeQMBr2 and three ILs, AlMeImCl, AlBuImCl e AlHxImCl. The results showed the importance of probe-LI interaction, for example, hydrogen bond, electrostatic and hydrophobic interactions; that influences the solvation of the probe. The SAILs studied series, was the 1-methyl-3(3-acylaminopropyl) imidazolium chloride, this series was synthesized, purified and characterized. The properties of the surfactants aqueous solutions were investigate with conductance, surface tension, light scattering and solvatochromism. The values of critical micelle concentration, cmc, and Gibbs free energy, ΔGmic, was obtained with the first three techniques, and these results were compared with the series 1-methyl-3-alkylimidozolium chlorides. The results showed that the presence of the amide functional group support the micellization process. In the solvatochromic study of micellar solutions, they were utilized the probes WB, 4-nitroanisole, 4-nitroaniline e N,N-dimethyl-4-nitroaniline. Using these probes, it was possible to determine the acidity, α, basicity, β, polarizability, π* and interfacial water concentration, [water]interfacial. It was observed, that α, β and [water]interfacial decreased with the increase of the hydrophobic chain of the surfactant.
Ungarato, Rafael Fernando De Santi 1988. "Influência da molhabilidade de rochas na recuperação avançada de petróleo : um estudo por RMN." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250155.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: O estudo de soluções para métodos especiais de recuperação de petróleo vem sendo amplamente utilizado, principalmente devido à grande quantidade de óleo remanescente nos reservatórios após as recuperações primária e secundária. Soluções consideradas de potencial recuperador devem possuir algumas características específicas como uma baixa tensão interfacial água/óleo e viscosidade moderada, de modo a melhorar a eficiência do petróleo varrido. Interações fluidos-rocha e óleo-rocha são determinantes no montante de óleo a ser recuperado, assim sendo, estudos com relação à molhabilidade das superfícies das rochas mostram-se fundamentais. Um método de análise largamente empregado e considerado como padrão para medidas de molhabilidade é o teste de Amott, porém, tal método apresenta grande tempo de análise e preparo de amostra. O presente trabalho analisa a molhabilidade de rochas utilizando-se a técnica de Ressonância Magnética Nuclear de Baixo Campo. Ela se baseia nos tempos de relaxação da magnetização das populações de água e óleo, livres ou ligadas na superfície da rocha, permitindo de maneira rápida, a determinação da quantidade de óleo removida. Nesse estudo foram analisadas amostras de arenito e carbonato, caracterizando-as comparativamente com relação ao tamanho e homogeneidade dos poros por dados de RMN. As rochas foram impregnadas com petróleo e deixadas em contato com diferentes soluções de surfactantes (não iônico e zwiteriônico), sendo possível a análise quanto à diferença de molhabilidade entre as mesmas. Com relação a essas soluções, foram utilizados diversos surfactantes, com diferenças quanto aos grupos funcionais, ao tamanho da cadeia hidrofóbica, a presença de uma ou duas dessas cadeias e em diferentes concentrações, sendo possível a obtenção de informações relacionadas à eficiência de extração de óleo para cada uma delas. Observou-se que a técnica utilizada apresentou excelentes resultados, permitindo diferenciar a capacidade de extração para cada solução estudada
Abstract: The study of solutions to enhance oil recovery has been widely used, mainly due to large amount of oil that remains in reservoirs after primary and secondary recoveries. Solutions with good potential to recovery must have some specific characteristics such as low water/oil interfacial tension and a moderate viscosity to improve the efficiency of the oil swept. The fluid-rock and oil-rock interactions are of great importance concerning the total oil recovered. Therefore, studies involving wettability of rock surfaces are essential. A traditional method of analysis, which is considered as standard to measures the wettability is the Amott test, however, this method spends too much time and sample preparation. This study analyzes rock wettability using the technique of Low Field Nuclear Magnetic Resonance (low-field NMR). This is based on the relaxation rates of the magnetization of water and/or oil molecules, free or bounded at the surface of the pores of the rock. The technique allows a quick determination of the amount of oil removed. In the present study, the size and pores homogeneity of sandstone and carbonate were analyzed using low field-NMR. The rocks were impregnated with oil and then left in contact with different solutions of surfactants (non-ionic and zwitterionic), being possible to analyze the differences in wettability among them. Several concentrations of surfactants, in which differences in their: functional groups, hydrophobic chain length and number of chains, were studied. The NMR technique revealed excellent results, providing information related to the efficiency of oil extraction for each studied solution
Mestrado
Físico-Química
Mestre em Química
Chen, Yi-Chia, and 陳怡嘉. "Antioxidative capacity and synergistic effect of selected antioxidant mixtures." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/50055983279702311025.
Повний текст джерела臺北醫學大學
生醫材料暨工程研究所
97
Although there were studies suggest that the combination of antioxidants may effectively enhance free radical scavenging efficacy and may exert some synergistic effect, there is still no in-depth research in this area regarding the relationship between the compositions of the ingredients, their concentrations and ratios, and whether they may result in synergistic antioxidative effect. Many commercial anti-aging and antioxidative products are mixtures of various antioxidants, but there is no study yet today to provide in which composition of the antioxidant mixtures is the most optimal formulation for antioxidant. The purpose of this study is to investigate the potential synergistic relationship between various combinations of the four antioxidants: vitamin E, vitamin C, lutein/zeaxanthin, and green tea polyphenol (EGCG). The antioxidative ability of the antioxidants was evaluated by the DPPH method. An experimental design software was introduced in this study to construct the conditions of the 2-component, 3-component, and 4-component antioxidant combinations. The synergistic effect of the antioxidant combination was evaluated mathematically using two calculation modes. Our results showed that the combination of vitamin E, vitamin C, and green tea polyphenol (2-component or 3-component) exerted synergistic antioxidative effect. However, the combination of all the 4 components did not provide synergistic antioxidative effect.
Lee, Song-Bor, and 李松柏. "Synergistic effect of mixed surfactants for surface tension reduction and micelle formation." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/37824472900972591974.
Повний текст джерела國立成功大學
化學工程學系
86
It can be found in many surfactant applications that they give much stronger surface activities than single surfactant components. This phenomena is normally called synergism. In this work the synergism of surface tension reduction and micelle formation in anionic/cationic surfactant mixtures(SDS/CPC) is studied by using surface tension method. The heat change and the mechanism of micelle formation are also studied by using of isothermal titration calorimetry method. The experiment results show that SDS/CPC mixed surfactant systems have strong synergistic effect in surface tension reduction and micelle formation. The interaction parameters, bs for mixed monolayer on the air/water interface ,and bm for mixed micelles, have large negative values. This show that the molecular interactions are attractive forces. By the measurement of surface tension reduction with time, we found that surfactant mixtures have obvious dynamic adsorption behavior. For the case of pure surfactants, micellization is endothermic. Because the values of free energy change, calculated by mass-action model are positive, the micellization process is spontaneous. And the thermodynamic principles show that, micellization is an entropy driven process. In mixed systems, the SDS/TX-100(1/1) mixtures has no obvious synergism, and its behavior are dominated by TX-100. In SDS/CPC(1/1) mixtures, because of the strong ionic- bond interactions , the result can not be analysis.
Chien, Chen-Lung, and 簡振龍. "A Study on Synergism in Binary Mixtures of Anionic/Cationic Surfactants." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/42017246042223349271.
Повний текст джерела國立成功大學
化學工程學系
88
In this work, catanionic surfactants of CP‧DS and DTMA‧DS were prepared by mixing equimolar CPC and DTMAC solutions, respectively, with SDS solutions and followed by separation and purification processes including centrifugal filtration, washing, and vacuum drying. The solid precipitate was subsequently subjected to analyses with elemental analyzer (EA), mass spectrometer (MASS), and Fourier transform infrared spectrometer (FTIR) for chemical structure identification. The results of EA reveal the solid precipitates contain finite elements which have constant weight percent including C、H、O、N、S. The molecular weights are determined to be 570 and 494 g/mole, respectively, for CP‧DS and DTMA‧DS by MASS. Some marked groups of the solid precipitates can be found by FTIR. These results lend evidence to the formation of catanionic surfactants by anionic and cationic surfactants in equimolar. In addition, the surface activities of these two catanionic surfactants were also measured. The data were measured by maximum bubble pressure tensiometer show the dynamic adsorption behaviors of CP‧DS and DTMA‧DS are similar to pure water. CP‧DS and DTMA‧DS with high surface activities were also measured and compared with those observed by equilibrium surface tensions for solutions of the single and binary mixed surfactants. With the appropriate theoretical models, we can calculate the equilibrium adsorption parameters (such as m、KL) and investigate the equilibrium adsorption behaviors of CP‧DS and DTMA‧DS. As for the dynamic adsorption behaviors of these two catanionic surfactants, experimental results with the theoretical analysis show that the dynamic adsorption processes of CP‧DS and DTMA‧DS are diffusion controlled.
Mohsenipour, Ali Asghar. "Turbulent Drag Reduction by Polymers, Surfactants and Their Mixtures in Pipeline Flow." Thesis, 2011. http://hdl.handle.net/10012/6393.
Повний текст джерелаChen, Bing-Hung. "Rates of solubilization of triolein and triolein/fatty acid mixtures and dissolution processes of neat surfactants." Thesis, 1998. http://hdl.handle.net/1911/19248.
Повний текст джерелаTARLO, KIRK STANLEY. "SYNERGISTIC EFFECT ON MUTANT FREQUENCIES AND CHROMATID-TYPE ABERRATIONS BY BINARY MIXTURES OF METHYL METHANESULFONATE AND ETHYL METHANESULFONATE." 1988. http://books.google.com/books?id=MNA9AAAAMAAJ.
Повний текст джерелаAbdel-Rahem, Rami [Verfasser]. "Phase behavior and structural transitions in the mixtures of cationic surfactants and hydrophobic counterions / vorgelegt von Rami Abdel-Rahem." 2003. http://d-nb.info/969146299/34.
Повний текст джерелаLin, Ji-Yu, and 林紀妤. "Inhibitory effect of skin-whitening agents on tyrosinase activity under varying pH conditions and the synergistic effect of skin-whitening agent mixtures." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/p87f66.
Повний текст джерела嘉南藥理大學
化粧品應用與管理系
103
Skin whitening has invariably been a skin effect desired among Asian women. Overexpression and accumulation of melanin influence the overall aesthetics of a person and easily induce various types of skin pigmentation diseases. Tyrosinase is a key enzyme for melanin synthesis. Inhibiting the activity of this enzyme and accelerating the metabolism of melanocytic skin cells yield skin-whitening effects. In this study, α-arbutin, L-ascorbic acid, hydroquinone, kojic acid, magnesium ascorbyl phosphate, sodium ascorbyl phosphate, and tranexamic acid were used. The inhibitory effects that mixtures containing either two of the aforementioned substances have on tyrosinase activity were investigated under varying pH conditions ( pH=3~8 ). Subsequently, the effects of these mixtures on cytotoxicity and intracellular tyrosinase activity were determined. The experimental results showed that the samples most of the optimally inhibited the activity of mushroom tyrosinase under a pH condition of 3. Mixing kojic acid with hydroquinone exerted a synergistic effect; in addition, when 0.7% kojic acid was mixed with 0.3% hydroquinone, the optimal mixing effect under the same final concentration was achieved. For this mixture, the cytotoxicity test revealed that the toxicity of hydroquinone decreased with increasing proportion of kojic acid. The test results for intracellular tyrosinase activity showed that this aspects also decreased as the proportion of kojic acid was increased.
Lai, Ching-Ting, and 賴慶庭. "Assessment of toxicity, synergistic effects and field control efficacy of the binary mixtures of five commercial insecticides to the brown planthopper Nilaparvata lugens." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/37515338498986504143.
Повний текст джерела國立屏東科技大學
植物醫學系所
104
The brown Planthopper (BPH), Nilaparvata lugens is a major pest of rice production in tropical Asia. In many countries, BPH causes serious economic loss on rice yield by sucking rice sap and transmitting various of rice virus diseases. The appearance of insecticide resistance challenges the control of BPH in field. The development of new insecticide is expensive and time-consuming. Thus, the precise and proper use of existing compounds becomes an important issue in resistance management of this pest. Pesticide rotation is an effective approach in resistance management. However, practice of pesticide rotation is not accustomed for traditional farmers, and this strategy also is inappropriate to the pest which developed multiple resistances. In this study, five commercial insecticides of BPH (Chlorpyrifos, Permethrin, Imidacloprid, Clothianidin and Thiamethoxam) were tested by rice seedling dipping bioassay method to explore the toxicity of the binary mixture between various kinds of insecticides. Base on the results of estimated Combination Index (CI), mixture of Chlorpyrifos and Neonicotinoids showed antagonistic effect in all combinations. The mixtures of Permethrin and Neonicotinoids showed synergistic (CI<1) and additive effect (CI=1) in most of cases. The mixtures of Chlorpyrifos/Permethrin displays synergistic effect at three different mixture ratio (1:1、1:10 and 10:1). The strongest synergism observed in Chlorpyrifos/ Permethrin mixtures at 1:1 ratio (CI=0.39). The Results of field trails showed the mixture of Chlorpyrifos 50ppm + Permethrin 50ppm increased the field control efficiency significantly rather than solo treatment of Chlorpyrifos or Permethrin. The result showed the mixture of Chlorpyrifos and Permethrin showed more than 86% control rate during the period of 1 to 14 days after spraying. Addition of enzyme inhibitor followed by detoxification enzyme activity assays suggested that the mechanism of synergistic effect of Chlorpyrifos/Permethrin mixture may result from the cytochrome P450 and esterase active site competition between Chlorpyrifos and Permethrin; Analysis of CYP(cytochrome P450) gene expression revealed that, when BPH treated with binary mixtures of Chlorpyrifos and Permethrin, the expression of NlCYP303A1 were significantly decreased compare with Chlorpyrifos or Permethrin treatment. This finding indicated that, the insecticide-induced up-regulation of CYP gene might be interfered by mixture of insecticides. This phenomenon provided some issues about the mechanism of synergistic effect between organophosphate and pyrethroid in future work.
Liao, Chun-Yen, and 廖俊彥. "Synthesis and Study of Hydrogen-Bonded Bent Core Liquid Crystalline Mixtures Containing C60 Surface-Modified with Single and Double Benzoic Acid Surfactants." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/09027417812510703974.
Повний текст джерела國立交通大學
材料科學與工程學系所
102
In this study we prepared novel composites materials from the hydrogen-bonded bent-core liquid crystal (LC) host and different mole ratios (0–90 mol%) of the surface-modified fullerenes(C60). The chemical structures of these compounds were characterized by 1H-NMR, 13C-NMR, IR spectra, MS as well as elemental analysis, and the liquid crystalline phases and mesomorphic behavior of all the compounds were identified from the results of DSC, POM, electro-optical measurement and XRD. The mesomorphic properties of the composites, including their mesophasic types and ranges, values of Ps, and saturated electric field were adjustable by varying the doping concentrations of fullerenes. By increasing the concentration of fullerenes, the polarity of the SmCP phase in the composite varied sequentially from anti-ferroelectricity to ferroelectricity. Futhermore, adding a little amount of surface-modified fullerenes make the mixtures possesses the best Ps value and saturated electric field.