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Articoli di riviste sul tema "Reverse and direct emulsions":
1
Ramos, Diego M., Véronique Sadtler, Philippe Marchal, Cécile Lemaitre, Frédérick Niepceron, Lazhar Benyahia e Thibault Roques-Carmes. "Particles’ Organization in Direct Oil-in-Water and Reverse Water-in-Oil Pickering Emulsions". Nanomaterials 13, n. 3 (17 gennaio 2023): 371. http://dx.doi.org/10.3390/nano13030371.
Abstract (sommario):
This paper addresses the impact of the particle initial wetting and the viscosity of the oil phase on the structure and rheological properties of direct (Oil/Water) and reverse (Water/Oil) Pickering emulsions. The emulsion structure was investigated via confocal microscopy and static light scattering. The flow and viscoelastic properties were probed by a stress-controlled rheometer. Partially hydrophobic silica particles have been employed at 1 and 4 wt.% to stabilize dodecane or paraffin-based emulsions at 20 vol.% of the dispersed phase. W/O emulsions were obtained when the particles were dispersed in the oily phase while O/W emulsions were prepared when the silica was introduced in the aqueous phase. We demonstrated that, although the particles adsorbed at the droplets interfaces for all the emulsions, their organization, the emulsion structure and their rheological properties depend in which phase they were previously dispersed in. We discuss these features as a function of the particle concentration and the oil viscosity.
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Yang, Haixia, Steven R. Schmid, Ronald A. Reich e Thomas J. Kasun. "Direct Observations of Emulsion Flow in Elastohydrodynamically Lubricated Contacts". Journal of Tribology 128, n. 3 (27 marzo 2006): 619–23. http://dx.doi.org/10.1115/1.2198211.
Abstract (sommario):
The lubrication mechanisms with oil-in-water emulsions have been extensively investigated based on the measurements of film thickness and/or tractions in the past few decades. However, direct observation of the emulsion flow, as a more direct method of evaluating suggested explanations, has been greatly restricted by the available instruments, especially the cameras used in collaboration with high-speed bearing simulators. In this paper, a newly devised digital video camera and a microscope were used to directly observe the emulsion flow in an elastohydrodynamic lubrication (EHL) inlet region at a wide range of speeds (0.012m∕s up to 1.5m∕s). Both EHL line and point contacts were considered. Previous observations of low speed oil droplet “stay,” “reverse,” and “penetration” behavior for low-speed line contact were confirmed and extended into high-speed line and point cases, and the results were compared with point contact where significant side flow was observed. Three tight emulsions with different mean droplet sizes were examined on an EHL rig to clarify the droplet behavior and investigate the effect of droplet size on entrainment.
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Akram, Salman, Nicolas Anton, Ziad Omran e Thierry Vandamme. "Water-in-Oil Nano-Emulsions Prepared by Spontaneous Emulsification: New Insights on the Formulation Process". Pharmaceutics 13, n. 7 (7 luglio 2021): 1030. http://dx.doi.org/10.3390/pharmaceutics13071030.
Abstract (sommario):
Nano-emulsions consist of stable suspensions of nano-scaled droplets that have huge loading capacities and are formulated with safe compounds. For these reasons, a large number of studies have described the potential uses of nano-emulsions, focusing on various aspects such as formulation processes, loading capabilities, and surface modifications. These studies typically concern direct nano-emulsions (i.e., oil-in-water), whereas studies on reverse nano-emulsions (i.e., water-in-oil) remain anecdotal. However, reverse nano-emulsion technology is very promising (e.g., as an alternative to liposome technology) for the development of drug delivery systems that encapsulate hydrophilic compounds within double droplets. The spontaneous emulsification process has the added advantages of optimization of the energetic yield, potential for industrial scale-up, improved loading capabilities, and preservation of fragile compounds targeted for encapsulation. In this study, we propose a detailed investigation of the processes and formulation parameters involved in the spontaneous nano-emulsification that produces water-in-oil nano-emulsions. The following details were addressed: (i) the order of mixing of the different compounds (method A and method B), (ii) mixing rates, (iii) amount of surfactants, (iv) type and mixture of surfactants, (v) amount of dispersed phase, and (vi) influence of the nature of the oil. The results emphasized the effects of the formulation parameters (e.g., the volume fraction of the dispersed phase, nature or concentration of surfactant, or nature of the oil) on the nature and properties of the nano-emulsions formed.
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Istratov, V. V., V. I. Gomzyak, O. V. Yamskova, G. D. Markova, L. G. Komarova, B. A. Izmaylov e V. A. Vasnev. "Novel polymer surfactants based on the branched silatrane-containing polyesters and polyethers". Fine Chemical Technologies 14, n. 5 (14 novembre 2019): 61–70. http://dx.doi.org/10.32362/2410-6593-2019-14-5-61-70.
Abstract (sommario):
Objectives. Biologically active polymeric surfactants are a new promising class of macromolecules that can find application in medicine, cosmetology, and agriculture. In this study, a number of new biologically active amphiphilic polymers based on branched silatrane-containing polyesters and polyethers were obtained, and their surface-active properties were investigated.Methods. The branched polymers were represented by polyethers and polyesters, obtained respectively via the anionic polymerization of 1,2-epoxypropanol or a combination of equilibrium polycondensation and ring opening polymerization. The polymers were modified with 3-isocyanopropylsilatrane and trimethylethoxysilane to obtain the amphiphilic compounds containing silatrane groups bonded to the polymer backbone by the urethane bond. The structure of the synthesized polymer silatranes was confirmed via nuclear magnetic resonance spectroscopy and gel permeation chromatography. The surface active properties of all the copolymers obtained were investigated in connection with their obvious amphiphilicity. In particular, the formation of micelles in aqueous solutions is such a property. The critical micelle concentrations were determined by a method of quenching the fluorescence of the polymers.Results. It was shown that the values of the critical micelle concentrations and the hydrophilic-lipophilic balance values of polymers determined by the Griffin equation correlate well with each other. A linear relationship between the hydrophilic-lipophilic balance and the critical micelle concentrations was established. At the same time, polyether-based polymers generally showed higher critical micelle concentrations than polyester-based polymers, although the hydrophilic-lipophilic balance values for polymers of different series, but with close degrees of substitution, were close. It was found that the use of all synthesized polymers as stabilizers of direct and reverse emulsions leads to an increase in the aggregative stability of both types of emulsions. The stability of emulsions depended both on the degree of substitution of peripheral hydroxyl groups of polymers by silatranes and on the molecular weight and structure of the branched block of polymers. The stability of direct emulsions increased for all polymers, while that of inverse emulsions decreased with an increasing degree of substitution of hydroxyl groups by silatranes. The increase of the branched block molecular weight led to an increase of droplet sizes for both direct and inverse emulsions. The smallest droplet size for direct and inverse emulsions was obtained using polymers with low molecular weight branched polyester blocks as surfactants.Conclusions. The results obtained prove the possibility of creating polymer surfactants containing silatrane groups. By varying the structure of the polymer, its molecular weight and the degree of substitution of peripheral functional groups, it is possible to obtain surfactants with desired surface properties.
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Lisovaya, E. V., E. P. Viktorova, A. V. Sverdlichenko e M. R. Zhan. "The influence of the chemical composition of modified lecithins on their surface-active and emulsifying properties". New Technologies 19, n. 3 (5 dicembre 2023): 48–57. http://dx.doi.org/10.47370/2072-0920-2023-19-3-48-57.
Abstract (sommario):
It is known that lecithins are known to be natural emulsifiers due to the content of amphiphilic phospholipids. However, liquid lecithins widely produced by domestic enterprises have rather low emulsifying properties. Modification of liquid lecithins, which consists in a targeted change in their chemical composition, affects the effectiveness of the manifestation of certain technological properties, and, consequently, the directions of their use in emulsion food technologies. The purpose of the research was to study the influence of the characteristics of the chemical composition of modified lecithins, namely LecPC and LecFEI, on the effectiveness of the manifestation of surface-active and emulsifying properties. The modified lecithins LecPC and LecFEI were obtained from liquid soy lecithin using innovative technology with know-how. LecPC predominantly contains phosphatidylcholines – 85.5%, and LecFEI contains phosphatidylethanolamines in the largest amount – 30.0% of the total phospholipid content. The difference in the fatty acid composition of the modified lecithins LecPC and LecFEI was shown. As a result of the study of the effectiveness of the manifestation of surface-active properties by modified lecithins LecPC and LecFEI, it was revealed that the efficiency of manifestation of these properties of LecPC was higher than that of LecFEI. It was established that the modified lecithins LecPC and LecFEI exhibited high emulsifying ability, while the use of LecPC as an emulsifier provided stable direct-type emulsions, and the use of LecFEI – stable reverse-type emulsions, which was due to the peculiarities of their chemical composition. This allows us to recommend the modified lecithins LetsPC and LetsFEI as emulsifiers in the technologies of emulsion food products – mayonnaise, mayonnaise sauces, spreads and margarines.
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Sharifzadeh, Esmail, e Mehran Parsnasab. "Direct and reverse desymmetrization process in O/W Pickering emulsions to produce hollow graphene oxide Janus micro/nano-particles". Colloids and Surfaces A: Physicochemical and Engineering Aspects 619 (giugno 2021): 126522. http://dx.doi.org/10.1016/j.colsurfa.2021.126522.
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Muslimova, Indira B., Zh K. Zhatkanbayeva, Dias D. Omertasov, Galina B. Melnikova, Arman B. Yeszhanov, Olgun Güven, Sergei A. Chizhik, Maxim V. Zdorovets e Ilya V. Korolkov. "Stimuli-Responsive Track-Etched Membranes for Separation of Water–Oil Emulsions". Membranes 13, n. 5 (17 maggio 2023): 523. http://dx.doi.org/10.3390/membranes13050523.
Abstract (sommario):
In this work, we have developed a method for the preparation of pH-responsive track-etched membranes (TeMs) based on poly(ethylene terephthalate) (PET) with pore diameters of 2.0 ± 0.1 μm of cylindrical shape by RAFT block copolymerization of styrene (ST) and 4-vinylpyridine (4-VP) to be used in the separation of water–oil emulsions. The influence of the monomer concentration (1–4 vol%), the molar ratio of RAFT agent: initiator (1:2–1:100) and the grafting time (30–120 min) on the contact angle (CA) was studied. The optimal conditions for ST and 4-VP grafting were found. The obtained membranes showed pH-responsive properties: at pH 7–9, the membrane was hydrophobic with a CA of 95°; at pH 2, the CA decreased to 52°, which was due to the protonated grafted layer of poly-4-vinylpyridine (P4VP), which had an isoelectric point of pI = 3.2. The obtained membranes with controlled hydrophobic-hydrophilic properties were tested by separating the direct and reverse “oil–water” emulsions. The stability of the hydrophobic membrane was studied for 8 cycles. The degree of purification was in the range of 95–100%.
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Riess, Jean G., e Marie Pierre Krafft. "Fluorocarbons and Fluorosurfactants for In Vivo Oxygen Transport (Blood Substitutes), Imaging, and Drug Delivery". MRS Bulletin 24, n. 5 (maggio 1999): 42–48. http://dx.doi.org/10.1557/s0883769400052313.
Abstract (sommario):
The development of biomaterials to treat, repair, or reconstruct the human body is an increasingly important component of materials research. Collaboration between materials researchers and their industrial and clinical partners is essential for the development of this complex field. To demonstrate the importance of these interactions, two articles in this issue focus on advances in biomaterials relating to the use of colloidal systems for transport, drug delivery, and other medical applications. These articles were coordinated by Dominique Muster (Université Louis Pasteur, Strasbourg) and Franz Burny (Hôpital Erasme, Brussels). The following is the first of these two articles.A large variety of colloidal Systems involving highly fluorinated components have been prepared and investigated in recent years. These fluorinated Systems comprise diverse ty pes of emulsions (e.g., direct, reverse, and multiple emulsions; microemulsions; gel emulsions; waterless emulsions) with a fluorocarbon phase (and often a fluorinated Surfactant), and a ränge of self-assemblies (vesicles, tubules, helices, ribbons, etc.) made from fluorinated amphiphiles. Fluorinated Langmuir films and fluorinated black lipid membranes (BLMs) also have been investigated.Research in this area was driven by the potential applications of such materials in medicine and biology. Fluorocarbon-based products are being developed as injectable oxygen carriers (“blood Substitutes”), media for liquid Ventilation, drug delivery Systems, and contrast agents for ultrasound imaging. One such agent has recently been approved for use in Europe and the United States. Several more products are in an advanced stage of clinical evaluation, and others are in various stages of preclinical development. From a more fundamental Standpoint, these materials are being investigated for assessing and understanding the impact that fluorinated components have on the formation, stability, structure, and properties of colloida l Systems in comparison with their hydrocarbon counterparts. The attention given to fluorinated colloids prompted the synthesis of numerous new families of fluorinated amphiphiles, which were to become components of such colloids.
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Tsagogiorgas, Charalambos, e Matthias Otto. "Semifluorinated Alkanes as New Drug Carriers—An Overview of Potential Medical and Clinical Applications". Pharmaceutics 15, n. 4 (11 aprile 2023): 1211. http://dx.doi.org/10.3390/pharmaceutics15041211.
Abstract (sommario):
Fluorinated compounds have been used in clinical and biomedical applications for years. The newer class of semifluorinated alkanes (SFAs) has very interesting physicochemical properties including high gas solubility (e.g., for oxygen) and low surface tensions, such as the well-known perfluorocarbons (PFC). Due to their high propensity to assemble to interfaces, they can be used to formulate a variety of multiphase colloidal systems, including direct and reverse fluorocarbon emulsions, microbubbles and nanoemulsions, gels, dispersions, suspensions and aerosols. In addition, SFAs can dissolve lipophilic drugs and thus be used as new drug carriers or in new formulations. In vitreoretinal surgery and as eye drops, SFAs have become part of daily clinical practice. This review provides brief background information on the fluorinated compounds used in medicine and discusses the physicochemical properties and biocompatibility of SFAs. The clinically established use in vitreoretinal surgery and new developments in drug delivery as eye drops are described. The potential clinical applications for oxygen transport by SFAs as pure fluids into the lungs or as intravenous applications of SFA emulsions are presented. Finally, aspects of drug delivery with SFAs as topical, oral, intravenous (systemic) and pulmonary applications as well as protein delivery are covered. This manuscript provides an overview of the (potential) medical applications of semifluorinated alkanes. The databases of PubMed and Medline were searched until January 2023.
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Won, Mijin, Gyeongseok Oh, Hyunah Lee, Jaehwan Kim e Dong-Soo Kim. "Humidity Sensors Based on Cellulose Nanofiber Fabricated on a Three-Dimensional (3D) Curved Surface". Nanomaterials 13, n. 23 (23 novembre 2023): 3005. http://dx.doi.org/10.3390/nano13233005.
Abstract (sommario):
Traditional printed electronics processes have recently been utilized within 3D-printed structures where components and interconnects are introduced during manufacturing disruptions. The dielectric performance of 3D-printed materials has a low-resolution problem, and many technologies have been proposed for direct printing on a 3D curved surface or structure. This paper reports a humidity sensor fabricated with a 3D-printed electrode and cellulose nanofibers on a curved surface. The electrode part of an interdigital electrode (IDE) sensor is printed on a flat glass substrate and a 3D-curved glass substrate using a double blanket reverse offset. Subsequently, a cellulose nanofiber emulsion is coated onto the IDE pattern as a sensing layer with a dispenser. The electrical impedance of the sensor is measured with the relative humidity (RH) changes between 10% and 90% RH. The sensor demonstrates a high repeatability and sensitivity, even on a 3D curved substrate. This technology provides a promising method to integrate humidity sensors and 3D deformable surfaces.
Tesi sul tema "Reverse and direct emulsions":
1
Ramos, Diego. "Contrôle et caractérisation des propriétés d'émulsions de Pickering stabilisées avec des particules de silice à partir d'une approche type génie des produits formulés". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0204.
Abstract (sommario):
Le génie des produits formulés propose une démarche pour essayer de comprendre et contrôler le lien entre les propriétés micro-, méso- et macroscopiques d'un produit fini. Dans cette démarche, la compréhension du comportement global du produit nécessite la caractérisation de ses trois échelles constitutives, afin de maîtriser ses propriétés d'usage et pouvoir remplir un cahier de charges (généralement imposé). Cette approche s'adapte à l'étude des systèmes hors-équilibre et à plusieurs composants. Les émulsions de Pickering, ou émulsions stabilisées avec des particules solides, représentent un terrain expérimental riche pour utiliser cette approche. Dans le cadre de cette thèse, nous avons travaillé avec des particules de silice commerciales pour stabiliser les émulsions. La taille et la mouillabilité des particules ont été caractérisées. La nature des émulsions pouvait être directe inverse eau-dans-huile ou directe huile-dans-eau. De plus, nous avons testé trois agitateurs différents : turbine Rushton, rotor-stator et sonde à ultrasons pour les préparer. Les caractérisations systématiques des émulsions concernaient la taille de goutte moyenne, le comportement rhéologique et la répartition des particules de silice entre les interfaces liquide/liquide et la phase continue. Nous avons trouvé que le couplage composition-procédé permettait de contrôler ces propriétés. Dans un premier temps, nous nous sommes intéressés aux émulsions inverses et directes préparées avec un même procédé d'émulsification. Dans un deuxième temps, nous avons proposé une étude systématique d'émulsions directes préparées principalement avec deux procédés d'émulsification. Et dans un dernier temps, nous avons essayé de pousser les limites de la composition de ces émulsions ainsi qu'une modélisation de leur comportement rhéologiqueThe chemical product design approach tries to understand and control the link between the micro-, meso- and macroscopic properties of a finished product. In this approach, the understanding of the global behavior of the product requires the characterization of its three constitutive scales, in order to control its end-use properties and to be able to fulfill a specification, which is generally imposed. This approach is adapted to the study of non-equilibrium and multi-component systems. Pickering emulsions, or particle-stabilized emulsions, are a rich experimental field to apply this approach. In this thesis, we worked with commercial silica particles to stabilize the emulsions. The size and wettability of the particles were characterized. The nature of the emulsions could be direct reverse water-in-oil or direct oil-in-water. In addition, we tested three different stirrers: Rushton turbine, rotor-stator and ultrasonic probe to prepare them. Systematic characterizations of the emulsions concerned the average drop size, the rheological behavior and partitionning of the silica particles between the liquid/liquid interfaces and the continuous phase. We found that the composition-process coupling allowed to control these properties. In a first step, we focused on reverse and direct emulsions prepared with the same emulsification process. In a second step, we proposed a systematic study of direct emulsions prepared mainly with two emulsification processes. And in a third time, we tried to push the limits of the dispersed phase fraction of these emulsions as well as a modeling of their rheological behavior
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Ghiu, Silvana Melania Stefania. "Mass Transfer of Ionic Species in Direct and Reverse Osmosis Processes". [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000176.
3
Nelson, Diane L. "Pulmonary Drug Delivery via Reverse Perfluorocarbon Emulsions: A Novel Method for Bacterial Respiratory Infections and Acute Respiratory Failure". Research Showcase @ CMU, 2018. http://repository.cmu.edu/dissertations/1147.
Abstract (sommario):
Inhaled drug delivery is currently the gold standard for treating many respiratory diseases. However, improved treatments are needed for lung diseases like Cystic Fibrosis (CF) and Acute Respiratory Distress Syndrome (ARDS), where mucus or fluid build-up in the lung limits ventilation and, thus, delivery of inhaled drugs. Delivery is most needed in the diseased or damaged regions of the lung, but if an area is not ventilated, inhaled drug will simply not reach it. To overcome this, this research proposes delivering drugs to the lungs within a perfluorocarbon (PFC) liquid. The lungs will be filled with a reverse emulsion containing a disperse phase of aqueous drugs within the bulk PFC and then ventilated. The PFC functions as both a respiratory medium, providing gas exchange, and as a delivery vehicle, providing a more uniform deposition of drugs. After treatment, the highly volatile PFCs are exhaled, returning the patient to normal respiration. This technique improves upon current therapies as follows. First, drugs are delivered directly to where they are needed, yielding higher concentrations in the lung and lower systemic concentrations. Second, PFCs are ideal for washing out lung exudate and mucus. The low surface tension and high density of PFC allows it to easily penetrate plugged or collapsed alveoli, detach infected mucus from the airway walls, and force these fluids to the top of the lungs where they can then be removed via suction. Mucus and exudate removal should allow drugs to penetrate previously plugged airways during emulsion delivery and subsequent treatment with inhaled therapies. Thus, drug delivery via emulsion would be used as a pre-treatment to enhance inhaled or systemic drug therapy. Third, PFC’s anti-inflammatory properties help return to normal lung function. This research examines two applications of this technology: delivery of antibiotics to combat respiratory infections (antibacterial perfluorocarbon ventilation, APV) or delivery of growth factors to enhance alveolar repair (perfluorocarbon emulsions for alveolar repair, PEAR). This work represents an in-depth analysis of the emulsions used during APV and PEAR. Initial efforts evaluated emulsion efficacy under in vitro setting that better simulated lung in vivo antibiotic delivery. The subsequent studies utilized an in vivo rat model of bacterial respiratory infection to validate the effects of emulsion on pharmacokinetics and to assess APVs potential treatment benefits. Lastly, in vitro methods of cellular response assessed the utility of delivering growth factors in PEAR. Significant advancements were made in optimizing the emulsion as a viable means of pulmonary drug delivery. Final efforts resulted in a promising emulsion formulation that overcame the quick transport of tobramycin away from the lung and successfully reduced pulmonary bacterial load in vivo. In vitro applications of PEAR showed the emulsions posed a significant barrier to the availability and, thus, the biological effect of lysophosphatidic acid growth factors. Further in vivo work is required to improve APV’s efficacy over conventional treatments and to determine PEAR’s feasibility and efficacy in promoting lung repair.
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Mandich, Nenad V. "Mechanisms of chromium deposition and dissolution under direct and pulse reverse plating conditions". Thesis, Aston University, 1996. http://publications.aston.ac.uk/15349/.
Abstract (sommario):
Baths containing sulphuric acid as catalyst and others with selected secondary catalysts (methane sulphonic acid - MSA, SeO2, a KBrO3/KIO3 mixture, indium, uranium and commercial high speed catalysts (HEEF-25 and HEEF-405)) were studied. The secondary catalysts influenced CCE, brightness and cracking. Chromium deposition mechanisms were studied in Part II using potentiostatic and potentiodynamic electroanalytical techniques under stationary and hydrodynamic conditions. Sulphuric acid as a primary catalyst and MSA, HEEF-25, HEEF-405 and sulphosalycilic acid as co-catalysts were explored for different rotation, speeds and scan rates. Maximum current was resolved into diffusion and kinetically limited components, and a contribution towards understanding the electrochemical mechanism is proposed. Reaction kinetics were further studied for H2SO4, MSA and methane disulphonic acid catalysed systems and their influence on reaction mechanisms elaborated. Charge transfer coefficient and electrochemical reaction rate orders for the first stage of the electrodeposition process were determined. A contribution was made toward understanding of H2SO4 and MSA influence on the evolution rate of hydrogen. Anodic dissolution of chromium in the chromic acid solution was studied with a number of techniques. An electrochemical dissolution mechanism is proposed, based on the results of rotating gold ring disc experiments and scanning electron microscopy. Finally, significant increases in chromium electrodeposition rates under non-stationary conditions (PRC mode) were studied and a deposition mechanisms is elaborated based on experimental data and theoretical considerations.
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Delviks, Krista Anda. "Development of murine leukemia virus-based vectors for more effective gene therapy genetic analysis of direct repeat deletions /". Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=642.
Abstract (sommario):
Thesis (Ph. D.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains vi, 119 p. : ill. Vita. Includes abstract. Includes bibliographical references.
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Hussain, Moeed. "Optical Scattering Properties of Fat Emulsions Determined by Diffuse Reflectance Spectroscopy and Monte Carlo Simulations". Thesis, Linköping University, Department of Biomedical Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-54284.
Abstract (sommario):
To estimate the propagation of light in tissue-like optical phantoms (fat emulsions), this thesis utilized the diffuse reflectance spectroscopy in combination with Monte Carlo simulations. A method for determining the two-parametric Gegenbauer-kernal phase function was utilized in order to accurately describe the diffuse reflectance from poly-dispersive scattering optical phantoms with small source-detector separations. The method includes the spectral collimated transmission, spatially resolved diffuse reflectance spectra (SRDR) and the inverse technique of matching spectra from Monte Carlo simulations to those measured. An absolute calibration method using polystyrene micro-spheres was utilized to estimate the relation between simulated and measured SRDR intensities. The phase function parameters were comparable with previous studies and were able to model measured spectra with good accuracy. Significant differences between the phase functions for homogenized milk and the nutritive fat emulsions were found.
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Eaton, Yatika C. "A Framework for Integration of Forward and Reverse Logistics Into a Single Facility". Ohio University / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1168547069.
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Candéa, Tatiana Vidal. "Study of membrane emulsification process as a pre-step for the microencapsulation of lipid compounds by spray drying". Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10412.
Abstract (sommario):
Dissertation presented to Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa for obtaining the master degree in Membrane EngineeringFood emulsions play an important role in product development and formulation, as well as to encapsulation of food additives. Conventional methods for emulsion production may present some drawbacks, such as the use of high shear stress, high energy demanding and polydisperse droplet size distribution. In this sense, membrane emulsification emerges as an alternative method to overcome all this issues and to produce fine and stable emulsions. Linseed oil has been widely studied in the last years, due to its nutritional composition, being the richest ω-3 vegetable source and for that reason it was used as the raw material for emulsion production. Premix and direct (cross flow) membrane emulsification were carried out using three different membrane materials: polissulphone, cellulose ester and α-alumina membrane. For premix membrane emulsification (PME) the variables transmembrane pressure, membrane material, surfactant type and membrane mean pore size were evaluated. The membrane mean pore size was the crucial factor to achieve emulsions by PME, once it was not possible to achieve stable emulsion with mean pore sizes lower than 0.8 μm. For direct membrane emulsification, transmembrane pressure, surfactant concentration and cross flow velocity were evaluated by means of a experimental design. The evaluated responses were stability, droplet size and distribution and dispersed phase flux. For all the variables studied, only dispersed phase flux showed to have significant influence of pressure. Comparing both methods of membrane emulsification, premix showed to be more suitable in terms of emulsion production throughput and droplet size correlation with membrane pore size, however, in terms of stability, direct membrane emulsification showed much better results. Encapsulation of linseed oil by spray drying was promoted using the optimum point of the performed experimental design and the droplets size distribution has considerably changed with the addition of the wall material to the emulsion.
The EM3E Master is an Education Programme supported by the European Commission, the European Membrane Society (EMS), the European Membrane House (EMH), and a large international network of industrial companies, research centres and universities
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Dalke, Trevor. "Data Chunking in Quasi-Synchronous DS-CDMA". DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1187.
Abstract (sommario):
DS-CDMA is a popular multiple access technique used in many mobile networks to efficiently share channel resources between users in a cell. Synchronization between users maximizes the user capacity of these systems. However, it is difficult to perfectly synchronize users in the reverse link due to the geographic diversity of mobile users in the cell. As a result, most commercial DS-CDMA networks utilize an asynchronous reverse link resulting in a reduced user capacity. A possible compromise to increase the user capacity in the reverse link is to implement a quasi-synchronous timing scheme, a timing scheme in which users are allowed to be slightly out of synchronization. This paper suggests a possible way to implement a quasi-synchronous DS-CDMA reverse link using the method of “data chunking”. The basic premise is derived by making a link between TDMA and synchronous DS-CDMA. By considering some basic TDMA limitations, a proposed “data chunked” quasi-synchronous DS-CDMA system is derived from a TDMA system. The effects of such a system are compared to those of a chip interleaved system. MATLAB simulations are performed to analyze the performance of the system in the presence of small synchronization errors between users. Implementation of guard bands is explored to further reduce errors due to imperfect synchronization between users.
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Löfström, Åsa. "Diskriminering på svensk arbetsmarknad : en analys av löneskillnader mellan kvinnor och män". Doctoral thesis, Umeå universitet, Institutionen för nationalekonomi, 1989. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-65869.
Abstract (sommario):
The aim of this study is to examine whether, and to what extent, the differences in wages between women and men can be explained by discrimination against women in the labour market.The first part of the analysis is a cross-sectional analysis. Firstly, a model is estimated with wages as the dependent variable and with sex, individuals' qualifications, personal characteristics, occupation and the branch of industry in which they are employed as the independent variables. The results of this regression reveal that the hourly wage for a woman is about nine SEK lower than for a man. Separate wage functions for women and men show that women obtain a lower return from both education and work experience. A breakdown of the difference in wages reveals that most of the dissimilarity is explained by discrimination against women and very little by differences in men's and women's productivity. In the absence of discrimination, women's relative pay would be between 16 and 25 percent higher. The stability of the findings is checked by means of reverse regression. This resulted in discrimination against men in some cases and against women in others. Thus, different conclusions can be drawn from the two methods. In certain special cases the results produced by reverse regression are correct, whereas, in more general cases, the direct method shows itself to be more satisfactory. The study ends with an analysis of the effects of various laws and agreements on the development of women's wages and employment in Swedish industry. The introduction of equal pay, the removal of the ban on night work for women in industry and the wage solidarity policy have had a positive influence on the relative demand for women workers. The study's conclusions are, firstly, that the differences in pay between the sexes can partly be explained by discrimination against women. Secondly, within industry, wage discrimination against women has declined as a result of changes leading in an anti-discrimination direction.digitalisering@umu
Libri sul tema "Reverse and direct emulsions":
1
Vojinov, Mandich℗ĐhNenad. Mechanisms of chromium deposition and dissolution under direct and pulse reverse plating conditions. Birmingham: Aston University. Department of Mechanical and Electrical Engineering, 1996.
2
Doctor, Raiomond, e Karl Friedrich Geldner. The Avesta: A Lexico-statistical Analysis (direct And Reverse Indexes, Hapax Legomenon And Frequency Counts (Acta Iranica, 41). Peeters Bvba, 2004.
3
Doctor, Raiomond. The Avesta: A Lexico-Statistical Analysis (Direct And Reverse Indexes, Hapax Legomenon And Frequency Counts) (Acta Iranica) (Acta Iranica). Peeters, 2004.
4
Halpern, Richard. The Classical Inheritance. A cura di Michael Neill e David Schalkwyk. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780198724193.013.2.
Abstract (sommario):
The question of Shakespeare’s relation to the Greek and Roman playwrights has, historically, possessed a kind of amplitude that his relation to other kinds of tradition has not. While recent scholarship challenges the old claim that Shakespeare had no direct access to Greek drama, Seneca’s status as his chief classical influence remains unchallenged. Moreover, Seneca’s plays self-consciously broadcast their embeddedness in tradition in a way that would allow Shakespeare to reverse engineer Greek drama, even without direct access. His use of central Senecan motifs—excessive revenge, the ghost, furor—demonstrates his awareness that they are also figures for literary tradition.
5
Lahouti, Arash H., e Lisa Christopher-Stine. Toxic myopathies. A cura di Hector Chinoy e Robert Cooper. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198754121.003.0009.
Abstract (sommario):
Toxic myopathy symptoms range from myalgia and muscle cramps to severe weakness, bearing similarities to a number of other muscle conditions. Thus, when evaluating patients with muscle symptoms, an iatrogenic muscle problem should always be considered, to be able to distinguish a toxic from any other myopathy early on, preventing further muscle damage and to potentially reverse muscle injury by withdrawal of the toxic agent. Various commonly prescribed medications, as well as illicit drugs, may cause muscle damage. These substances may cause muscle injury through direct myotoxic effects, or indirectly through various mechanisms, such as electrolyte abnormalities and triggering, or disinhibiting the immune system response.
6
Miller, David, Claire Harkins, Matthias Schlögl e Brendan Montague. Conclusions. Oxford University Press, 2017. http://dx.doi.org/10.1093/acprof:oso/9780198753261.003.0011.
Abstract (sommario):
This book suggests the need to rethink our understanding corporate power in relation to public health. The most important finding has been the sheer variety and extent of corporate engagements in policy-related activities. This challenges those approaches that focus narrowly on the (downstream) policy process at the expense of the wider context. It also challenges definitions of lobbying that confine the activity to face-to-face or direct contact with officials. The chapter reviews our arguments about social movements from above and below and the nature of the erosion of civil society by corporate strategy. The latter part of the chapter examines prescriptions for public health, including the need to adopt a whole-government strategy cognisant of multiple corporate voices, engage firmly with corporations to reverse the trend towards partnership governance, and go much further with transparency reforms in government and the corporate works, civil society, and science.
7
Cheng, Thomas K. The Patent-Competition Interface in Developing Countries. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780192857354.001.0001.
Abstract (sommario):
For the vast majority of developing countries bereft of meaningful innovation capacity, foreign technology transfer is the main vehicle for technological progress. The chief dynamic policy consideration for these countries is hence incentives for technology transfer instead of innovation incentives. There are three main means of voluntary technology transfer: importation of technological goods, foreign direct investment, and technology licensing. Competition law regulation of patent exploitation practices interacts with these three means of technology transfer in different ways and an appropriate approach to the patent-competition interface for these countries needs to take these into account. Distilling all these considerations, the book proposes a development stage-specific approach to the patent-competition interface for developing countries. The approach is then applied to a number of patent exploitation practices, including unilateral refusal to deal, patent tying, excessive pricing for pharmaceuticals, reverse payment settlements, and restrictive licensing practices.
8
Lippert-Rasmussen, Kasper. Making Sense of Affirmative Action. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190648787.001.0001.
Abstract (sommario):
What makes affirmative action morally (un)justified? That is this book’s core question. Its main contribution consists in a meticulous scrutiny of the strength of the six main arguments for—i.e., the compensation, the anti-discrimination, the equality of opportunity, the role model, the diversity, and the integration-based justifications—and the five main objections to affirmative action—i.e., the reverse discrimination, the stigma, the mismatch, the publicity, and the merit-based objections—and of how these arguments relate to one another. The book argues that all of the five main objections to affirmative action are either flawed or quite limited in terms of their implications. With regard to the arguments in favor of affirmative action, the book shows why the anti-discrimination and equality of opportunity-based arguments provide strong justifications for many affirmative action schemes. In light thereof and the fact that the five most influential arguments against affirmative action are all flawed or otherwise weak, the overall claim defended in the book is that many of the schemes that people have in mind when they discuss affirmative action (many of which are presently on the retreat) are justified. However, the book also emphasizes that any definitive answer to the question Is affirmative action morally (un)justified? must rest on a wide range of empirical results in the social sciences etc., e.g., about the likely effects of various affirmative action schemes; and that the question, when posed in such general form (unlike when it is asked about specific schemes of affirmative action), admits of no direct positive or negative answer.
9
Dawson, Susan. Other bacterial diseasesStaphylococcal zoonoses. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780198570028.003.0026.
Abstract (sommario):
Staphylococcal species are common commensals of the skin and mucous membranes of humans and animals but only in very recent years has zoonotic infections been recognised. They can also be associated with infection and disease, especially coagulase positive organisms. Staphylococcus aureus is relatively frequently carried by humans in the nasal passages and is a cause of infections in people including bacteraemias in hospitalised patients. More recently some strains of Staphylococcus aureus have acquired a resistance gene (mecA) which renders them resistant to meticillin (meticillin-resistant Staphylococcus aureus, MRSA). MRSA isolates are of major importance in healthcare situations as well as increasingly in the community. Animals can also be carriers of Staphylococcus aureus although less frequently than humans and MRSA can be carried or infect several different host species. For companion animals such as dogs and cats, the most frequently isolated MRSA strains are similar to the common local human healthcare strains; thus for the UK, EMRSA-15 and -16. This suggests a reverse zoonosis with spill over from the human population into their companion animals. In horses the situation is different, with some horses carrying or infected with human epidemic strains but others infected with strains less frequently seen in people. For food-producing animals the picture is different again with a particular strain, ST398, which appears to circulate endemically in animal populations, such as pigs, and can spill over into the human population where it can cause carriage as well as infection and disease. The transmission appears to be by direct contact with animals rather than through the food-chain.Where risk factors for infection with MRSA have been studied in animals they appear similar to some of the risks for human infection. Therefore, for control of MRSA in animals measures such as improved hygiene and good antibacterial stewardship are important.
10
Kalinichenko, Evgeny. Theory and methods for calculating the inertial-braking characteristics of a ship. «Scientific Route» OÜ, 2020. http://dx.doi.org/10.21303/978-617-7319-30-5.
Abstract (sommario):
One of the most serious problems of modern navigation is the accident rate that occurs due to inept or belated maneuvering of ships. As a result of accidents in the world, more than 200 ships die every year and every fourth receives significant damage. Full-scale tests show that the stopping distance of large-tonnage ships turn out to be much less permissible, and shipbuilders are able to significantly reduce the astern power of such ships, making them cheaper at the expense of safety. The low accuracy of inertial-braking characteristics is mainly due to unqualified field tests. Analysis of graphs and tables based on the results of such tests show that the spread in the values of inertial-braking characteristics for ships of the same type reaches 30%, and in some cases even more. In many tables and graphs, inertial-braking characteristics are expressed in relative values and are not suitable for direct use when maneuvering a ship. Finally, even when graphical and/or tabular maneuvering information is available on the navigating bridge, it is difficult to use it when maneuvering a ship at night. The research carried out by the author results in: - creation of an alternative computational method for determining the inertial-braking characteristics of the ship, suitable for use on any on-board computer; - development of an improved methodology for calculating the path and time of acceleration and braking of the ship in various ahead motion modes; - development of a methodology for taking into account the influence of a passing and opponent current on the length of the stopping distance of the ship; - development of methods for solving applied problems, ensuring a decrease in the accident rate of ships during maneuvering. The obtained methods include the development of theoretical foundations, mathematical models and comparison of the calculated inertial-braking characteristics of ships with the data of a full-scale experiment. For the first time, to derive the calculated formulas for the time and stopping distance, theorems are used on the change in the momentum and kinetic energy during accelerated and decelerated motion of the ship. In the course of the study, the problems of calculating and formalizing the inertial-braking characteristics of the ship are being comprehensively solved. For the first time, the hypothesis that the nature of the change in the thrust force of the propeller during reverse can be approximated by linear equations has been substantiated and confirmed. The general results are used to calculate the inertial-braking characteristics of specific ships.
Capitoli di libri sul tema "Reverse and direct emulsions":
1
Lenzerini, Maurizio. "Direct and Reverse Rewriting in Data Interoperability". In Advanced Information Systems Engineering, 3–13. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-21290-2_1.
2
Vanco, Marek, e Guido Brunnett. "Direct Segmentation of Algebraic Models for Reverse Engineering". In Geometric Modelling, 207–20. Vienna: Springer Vienna, 2004. http://dx.doi.org/10.1007/978-3-7091-0587-0_17.
3
Guerrero-Lorente, Javier, Eva Ponce-Cueto e Edgar E. Blanco. "A Model that Integrates Direct and Reverse Flows in Omnichannel Logistics Networks". In Lecture Notes in Management and Industrial Engineering, 89–97. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-45748-2_10.
4
Arof, Saharul, M. S. Said, N. H. N. Diyanah, N. M. Noor, N. M. Yaakop, Philip Mawby, H. Arof e Emilia Noorsal. "Series Motor Four-Quadrant Direct Current Chopper: Reverse Mode, Steering Position Control with Double-Circle Path Tracking and Control for Autonomous Reverse Parking of Direct Current Drive Electric Car". In Advanced Structured Materials, 121–36. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-46036-5_12.
5
Pileni, M. P., P. Brochette e B. Lerebours Pigeonnière. "A Comparison of the Forward and Back Photoelectron Transfer in Direct and Reverse Micelles". In Chemical Reactions in Organic and Inorganic Constrained Systems, 253–61. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4582-1_20.
6
Pastor, Jesús T., Juan Aparicio e José L. Zofío. "A Unifying Framework for Decomposing Economic Inefficiency: The General Direct Approach and the Reverse Approaches". In International Series in Operations Research & Management Science, 487–604. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-84397-7_13.
7
Kumar, Munna, Ashish Kumar e Sanjay Kumar. "Photothermal Conversion Enhancement Study of Reverse Irradiation-Based Direct Absorption Solar Collector Using Ag Nanoparticles". In Lecture Notes in Mechanical Engineering, 281–89. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2188-9_26.
8
Arof, Saharul, M. S. Said, N. H. N. Diyanah, N. M. Noor, J. A. Jalil, Philip Mawby, H. Arof e Emilia Noorsal. "Series Motor Four-Quadrant DC Chopper: Reverse Mode, Direct Current Control, Triple Cascade PIDs, and Ascend-Descend Algorithm with Feedback Optimization for Automatic Reverse Parking". In Advanced Structured Materials, 137–50. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-46036-5_13.
9
Wang, Jenshi B., Charng-Ching Yeh e Han-Chang Gao. "A New Carbon Nanotube-Supported Pt–Ru Anodic Catalyst by Reverse Microemulsion for Direct Methanol Electro-oxidation". In Progress in Exergy, Energy, and the Environment, 937–42. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-04681-5_89.
10
McKechnie, Michelle L., Fanrong Kong e Gwendolyn L. Gilbert. "Simultaneous Direct Identification of Genital Microorganisms in Voided Urine Using Multiplex PCR-Based Reverse Line Blot Assays". In PCR Detection of Microbial Pathogens, 229–45. Totowa, NJ: Humana Press, 2012. http://dx.doi.org/10.1007/978-1-60327-353-4_15.
Atti di convegni sul tema "Reverse and direct emulsions":
1
Feofilaktova, O. V. "STUDY OF THE STORAGE OF BAS ENCAPSULATED IN EMULSION FOOD SYSTEMS". In I International Congress “The Latest Achievements of Medicine, Healthcare, and Health-Saving Technologies”. Kemerovo State University, 2023. http://dx.doi.org/10.21603/-i-ic-137.
Abstract (sommario):
The article presents the results of a comparative analysis of the persistence of biologically
active substances on the example of vitamins B1 and E, encapsulated in the matrix core of double
emulsion food systems, in the aqueous phase of the direct and fatty phase of the reverse emulsion
food systems. According to the results of the research, the efficiency of vitamin encapsulation in
double emulsion systems was established to increase their shelf life: at the end of storage, the residual content of vitamin B1 in the double emulsion system water-oil-water was 34% higher than
its content in the inverse emulsion, and the content of vitamin E in the emulsion system oil-wateroil at the end of the storage period was 24% more than in direct emulsion.
2
Almorihil, Jawaher, Aurélie Mouret, Isabelle Hénaut, Vincent Mirallés e Abdulkareem AlSofi. "Produced Water Quality: the Effects of Different Separation Methods". In SPE Europec featured at 82nd EAGE Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205161-ms.
Abstract (sommario):
Abstract Gravity settling represents the main oil-water separation mechanism. Many separation plants rely only on gravity settling with the aid of demulsifiers (direct or reverse breakers) and others chemicals such as water clarifiers if they are required. Yet, other complementary separation methods exist including filtration, flotation, and centrifugation. In terms of results and more specifically with respect to the separated produced-water, the main threshold on its quality is the dispersed oil content. Even with zero discharge and reinjection into hydrocarbon formations, the presence of residual oil in the aqueous phase represents a concern. High oil content results into formation damage and losses in injectivity which necessitates formation stimulations and hence additional operational expenses. In this work, we investigated the effects of different separation techniques on separated water quality. Based on the results, we identified potential improvements to the existing separation process. We used synthetic well-characterized emulsions. The emulsions were prepared at the forecast water:oil ratio using dead crude oil and synthetic representative brine. To clearly delineate and distinguish the effectiveness of different separation methods, we exacerbated the conditions by preparing very tight emulsions compared with what is observed on site. With that, we investigated three separation techniques: gravity settling, centrifugation, and filtration. First, we used jar tests to study gravity settling, then a benchtop centrifuge at two speeds to evaluate centrifugation potential. Finally, for filtration, we tested two options: membrane and deep-bed filtrations. Concerning the water quality, we performed solvent extraction followed by UV analyses to measure the residual oil content as well as light transmission measurements in order to compare the efficiency of different separation methods. The results of analyses suggest that gravity settling was not efficient in removing oil droplets from water. No separation occurred after 20 minutes in every tested condition. However, note that investigated conditions were severe, tighter emulsions are more difficult to separate compared to those currently observed in the actual separation plant. On the other hand, centrifugation significantly improved light transmission through the separated water. Accordingly, we can conclude that the water quality was largely improved by centrifugation. In terms of filtration, very good water quality was obtained after membrane filtration. However, significant fouling was observed. With deep-bed filtration, produced water quality remained good and fouling was no longer observed. On the basis of those results, we conclude that for our case study, centrifugation and deep-bed filtration techniques can significantly improve quality of the separated and eventually reinjected water. Thereby, integration of any of the two methods in the separation plant will lead to more efficient produced-water reinjection, eliminating formation damage and frequent stimulations. Yet, it is important to note that economics should be further assessed.
3
Almorihil, Jawaher, Aurélie Mouret, Isabelle Hénaut, Vincent Mirallès e Abdulkareem AlSofi. "Produced Water Quality: The Effects of Different Separation Methods for Water and Chemical Floods". In SPE Middle East Oil & Gas Show and Conference. SPE, 2021. http://dx.doi.org/10.2118/204650-ms.
Abstract (sommario):
Abstract Gravity settling represents the main oil-water separation mechanism. Many separation plants rely only on gravity settling with the aid of demulsifiers (direct or reverse breakers) and other chemicals such as water clarifiers if they are required. Yet, other complementary separation methods exist including filtration, flotation, and centrifugation. In terms of results and more specifically with respect to the separated produced-water, the main threshold on its quality is the dispersed oil content. Even with zero discharge and reinjection into hydrocarbon formations, the presence of residual oil in the aqueous phase represents a concern. High oil content results into formation damage and losses in injectivity which necessitates formation stimulations and hence additional operational expenses. In this work, we investigated the effects of different separation techniques on separated water quality. In addition, we studied the impact of enhanced oil recovery (EOR) chemicals on the different separation techniques in terms of efficiency and water quality. Based on the results, we identified potential improvements to the existing separation process. We used synthetic well-characterized emulsions. The emulsions were prepared at the forecast water: oil ratio using dead crude oil and synthetic representative brines with or without the EOR chemicals. To clearly delineate and distinguish the effectiveness of different separation methods, we exacerbated the conditions by preparing very tight emulsions compared with what is observed on site. With that, we investigated three separation techniques: gravity settling, centrifugation, and filtration. First, we used Jar Tests to study gravity settling, then a benchtop centrifuge at two speeds to evaluate centrifugation potential. Finally, for filtration, we tested two options: membrane and deep-bed filtrations. Concerning the water quality, we performed solvent extraction followed by UV analyses to measure the residual oil content as well as light transmission measurements in order to compare the efficiency of different separation methods. The results of analyses suggest that gravity settling was not efficient in removing oil droplets from water. No separation occurred after 20 minutes in every tested condition. However, note that investigated conditions were severe, tighter emulsions are more difficult to separate compared to those currently observed in the actual separation plant. On the other hand, centrifugation significantly improved light transmission through the separated water. Accordingly, we can conclude that the water quality was largely improved by centrifugation even in the presence of EOR chemicals. In terms of filtration, very good water quality was obtained after membrane filtration. However, significant fouling was observed. In the presence of EOR chemicals, filtration lost its effectiveness due to the low interfacial tension with surfactants and water quality became poor. With deep-bed filtration, produced water quality remained good and fouling was no longer observed. However, the benefits from media filtration were annihilated by the presence of EOR chemicals. Based on these results and at least for our case study, we conclude that centrifugation and deep-bed filtration techniques can significantly improve quality of the separated and eventually reinjected water. In terms of the effects of EOR chemicals, the performance of centrifugation is reduced while filtrations are largely impaired by the presence of EOR chemicals. Thereby, integration of any of the two methods in the separation plant will lead to more efficient produced-water reinjection, eliminating formation damage and frequent stimulations. Yet, it is important to note that economics should be further assessed.
4
Naka, Tatsuhiro. "Direction Sensitive Direct Dark Matter Search with Super-High Resolution Nuclear Emulsions". In The 3rd International Symposium on “Quest for the Origin of Particles and the Universe". Trieste, Italy: Sissa Medialab, 2017. http://dx.doi.org/10.22323/1.294.0018.
5
Keihany, Julian, e Sander Baaren. "Modeling Heat Pump Technology for Economically Attractive Decarbonized Oil Production Systems". In SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210380-ms.
Abstract (sommario):
Abstract Many operators with large stakes in unconventional shale oil plays have published targets to drastically reduce emissions with some considering carbon emission tax for economic evaluations of future projects. This creates the need for finding electrically powered alternatives to replace equipment that currently consumes fuel gas, such as fired heaters. Production facility designs for unconventional shale must be simple, robust and require relatively low CAPEX and OPEX to be economically viable. This poses a challenge for electrically powered alternatives because fuel gas is freely available at production systems, whilst electricity comes at a cost. To address this challenge, novel fully electric production system designs have been developed based on heat pump technology. The practical and economic feasibility for these designs are evaluated and demonstrated so that these can be considered as realistic solutions for future projects. The major reasons why crude oil must be heated at upstream production facilities are to break potential emulsions of oil and water and to stabilize the oil. Stabilizing the oil means that volatile components are removed from the crude, so that it can be transported and stored in tanks without emission and safety concerns. The novel production systems achieve this by pairing a single stage electrically driven heat pump with heat integration. The novel production system designs are analyzed using steady state and dynamic simulations employing industry accepted process simulation software. The steady state simulations generate metrics such as energy consumption, estimated emissions and hydrocarbon recovery which are used in conjunction with emission factors and other economic factors to compare the performance to standard production facilities. The dynamic simulations are used to demonstrate the feasibility for starting-up and controlling the facility for this novel technology application. The simulation results demonstrate that the heat pump based designs consume around 70% less electrical power compared to direct electrical heating. Further benefits are that the temperatures can be controlled at various stages in the process to substantially increase the facility's oil recovery. This also results in leaner gas, which is particularly attractive for facilities that include gas compression and dehydration. The increased oil recovery results in substantially higher revenue which leads to an economically more attractive design compared to a traditional facility, even without taking carbon emission tax into consideration. These comparisons are provided for different types of facilities during different production scenarios during varying weather conditions.
6
Nothelfer, Steffen, Florian Foschum e Alwin Kienle. "Direct determination of the spectrally resolved scattering phase function of suspensions and emulsions". In Diffuse Optical Spectroscopy and Imaging, a cura di Hamid Dehghani e Heidrun Wabnitz. SPIE, 2019. http://dx.doi.org/10.1117/12.2527132.
7
Masalova, Irina, e Alexander Ya Malkin. "Tube Transportation of Highly Concentrated Emulsions". In ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98342.
Abstract (sommario):
Tube transportation of highly concentrated emulsions is an important technological process in mining works. Emulsions used for this particular type of application are so-called “liquid explosives” — highly concentrated dispersions of aqueous droplets in a continuous oil phase. The concentration of droplets reaches 96w. %. The width of the inter-phase layers in such a multi-phase system is of the order of nano-level. The length of tube transportation in a real manufacturing process can be of the order of several miles. Hence, the design of the transportation line is of primary technical interest. The practical calculations are based upon comprehensive studies of the rheological properties of highly concentrated emulsions, including an understanding of the role of droplet size, concentration of disperse phase, temperature and time effects (stability of emulsions). Direct measurements were carried out in a wide shear rate range. The results of the measurements indicated that the emulsions under study are rheopectic liquids (viscosity increases over time at a constant shear rate). Their steady flow curve is typical for a visco-plastic medium and is well fitted by the Hershel-Bulkley model. The yield stress is of the order of several tens Pa. The choice of a rheological model is however not crucial for application, since transportation in real technological regimes takes place at high flow rates where the power-type model of flow curves dominates. Systematic studies demonstrated that wall slip is absent over the entire range of the shear stresses under study. This type of rheological behavior was then used for tube transportation design. A more careful examination (based on rheological as well as direct optical observations) also showed that inflation could be observed on the flow curve. It was proven that this type of rheological behavior is related to the two-step mechanism of the flow of a multi-phase liquid. Measurements of normal stresses in shear flows are in accordance with this model of flow. Aqueous droplets in the emulsions under study are super-cooled water solutions of nitrate salts, with the concentration of the latter being of the order of 85%. This system is thermodynamically unstable. The study of time effects (“aging”) showed that slow crystallization in dispersed droplets takes place. This leads to the evolution of the rheological properties of emulsions that can be treated as an emulsion-to-suspension transition. The work was carried out in the Flow Process Research Center, Engineering Faculty, Cape Peninsula University of Technology, Cape Town, Republic of South Africa.
8
Mowafy, Ahmed G. E. M. I., e Ingars Steiks. "Direct Driven Photovoltaic-Reverse Osmosis hybrid membrane system". In 2022 IEEE 63th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON). IEEE, 2022. http://dx.doi.org/10.1109/rtucon56726.2022.9978888.
9
Yang, Haixia, Steven R. Schmid, Ronald A. Reich e Thomas J. Kasum. "Direct Observations of Emulsion Flow in EHL Contacts". In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63074.
Abstract (sommario):
Oil-in-water emulsions are widely used as lubricants in metal forming, machining and some machinery elements where non-flammable lubricants are required. Their lubricating mechanisms have been extensively investigated based on the measurements of film thickness and/or traction in the past few decades and a number of physical explanations for their performance have been forwarded. However, direct observation of the emulsion flow, as a direct method of evaluating suggested theoretical explanations, has been greatly restricted by the available instruments. In this paper, a newly devised digital video camera and microscope were used to directly observe the emulsion flow in EHL contacts at industrially relevant speeds for both line and point contacts. Previous low-speed results for line contact were confirmed and extended into high-speed cases. That is, some droplets were rejected from the inlet, others penetrated to the contact zone, and others remained fixed in position a certain distance from the edge of contact. For point contact, side flow behavior was also observed, and the number of droplets that remained stationary were limited to a single streamline. To clarify the oil droplet behavior and investigate the effect of particle size on entrainment, three tight emulsions with different mean droplet sizes were examined on an EHD rig at speeds from 12 mm/s up to 1.5 m/s.
10
Villeneuve, Pierre, Claire Bourlieu-Lacanal, David McClements, Eric Decker e Erwann Durand. "Lipid oxidation in emulsions and bulk oils: A review of the importance of micelles". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/lzak8107.
Abstract (sommario):
Lipid oxidation is a major cause of quality deterioration in food or cosmetic products. In these matrices, lipids are often present in a bulk or in emulsified forms. In both systems, the rate, extent and pathway of oxidation are highly dependent on the presence of colloidal structures and interfaces because these are the locations where oxidation normally occurs. In bulk oils, reverse micelles (association colloids) are present and are believed to play a crucial role on lipid oxidation. Conversely, in emulsions, surfactant micelles are present that also play a major role in lipid oxidation pathways. This review discusses the current understanding of the influence of micellar structures on lipid oxidation. In particular, is discussed the major impact of the presence of micelles in emulsions, or reverse micelles (association colloids) in bulk oil on the oxidative stability of both systems. Indeed, both micelles in emulsions and associate colloids in bulk oil are discussed as nanoscale structures that can serve as reservoirs of antioxidants and pro-oxidants and are involved in their transport within the concerned system. Their role as nanoreactors where lipid oxidation reactions occur is also commented. Significance of your research to the AOCS membership? The results underline the importance of a better understanding of the role of micelles in the control of lipid oxidation in food or cosmetic products.
Rapporti di organizzazioni sul tema "Reverse and direct emulsions":
1
Loy, Duan S., Lyric C. Bartholomay e D. L. Hank Harris. Direct Delivery of VP19 Double-Stranded RNA into Litopenaeus vannamei by Reverse Gavage Induces Protection against White Spot Syndrome Virus Disease. Ames (Iowa): Iowa State University, gennaio 2013. http://dx.doi.org/10.31274/ans_air-180814-798.
2
Espinasa, Ramón, Martin Walter e Guillermo Adbel Musik Asali. Energy Reform and Local Content in Mexico: Effects in the Mining Sector. Inter-American Development Bank, aprile 2015. http://dx.doi.org/10.18235/0010611.
Abstract (sommario):
Mexico is one of the world's leading oil producers; it currently ranks tenth worldwide and first in the Latin American and Caribbean region. However, in the last 10 years, oil production has fallen by almost a million barrels a day. Declines in Crude oil exports have led to increases in imports, and negatively affected the balance of trade. To reverse this trend, the federal government promoted a reform in the energy sector which was approved in December 2013. This reform declared that oil and gas exploration and production were strategic activities, and promoted private investment in the hydrocarbon industry. In addition to the direct benefits generated by this investment in terms of increased production and lower prices, there is great potential for its impact on more sectors of the economy through vertical linkages. This study analyzes the future effect of the changes in the hydrocarbon sector on the mining sector, with emphasis on existing and potential linkages between the two sectors stemming from local content policies. This analysis will be useful for generating financial and public policy instruments that allow the mining sector to maximize benefits from the expected growth in the hydrocarbon sector over the next few years.
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Chioda, Laura, David Contreras-Loya, Paul Gertler e Dana Carney. Making Entrepreneurs: The Return to Training Youth in Hard versus Soft Business Skills. Centre for Excellence and Development Impact and Learning (CEDIL), aprile 2023. http://dx.doi.org/10.51744/crpp11.
Abstract (sommario):
We study the medium-term impacts of the Skills for Effective Entrepreneurship Development (SEED) program, an innovative in-residence 3-week mini-MBA program for high school students modeled after western business school curricula and adapted to the Ugandan context. The program featured two separate treatments: the hard skills MBA features a mix of approximately 75% hard skills and 25% soft skills; the soft skills curriculum has the reverse mix. Using data on 4,400 youth from a nationally representative sample in a 3-arm field experiment in Uganda, the 3.5 year follow-up demonstrated that training was effective in improving both hard and soft skills, but only soft skills were directly linked to improvements in self-efficacy, persuasion, and negotiation. Youth in both groups were more likely to start enterprises and more successful in ensuring their businesses’ survival. The program led to significantly larger profits (27.8% and 34.8% for hard and soft treatment arms respectively) and larger business capital investments (72.5% and 58.8% for SEED hard and SEED soft, respectively). Relative to the control group, SEED entrepreneurs created 550 new businesses and 985 additional jobs. The individual’s skill upgrade was rewarded by substantially higher earnings; 38.7% and 21.2% increases in earnings for those who attended hard- and soft-training, respectively, largely generated through self employment. Both SEED curricula were very cost-effective; one (two) month’s worth of extra earnings as a direct consequence of having attended the SEED hard (soft) program would exceed its total cost. 8.5 years post intervention, businesses led by SEED graduates are still more profitable than enterprises owned by the control group. To put these effect sizes into perspective, the control group would need to work 27.2 months and 16.25 months to match the business earnings accrued in a typical year by SEED hard and SEED soft graduates, respectively.
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Lers, Amnon, E. Lomaniec, S. Burd, A. Khalchitski, L. Canetti e Pamela J. Green. Analysis of Senescence Inducible Ribonuclease in Tomato: Gene Regulation and Function. United States Department of Agriculture, febbraio 2000. http://dx.doi.org/10.32747/2000.7570563.bard.
Abstract (sommario):
Natural leaf senescence has a negative influence on yield. Postharvest induced senescence contributes to the losses of quality in flowers, foliage, and vegetables. Strategies designed to control the senescence process in crop plants could therefore have great applied significance. Senescence is regulated by differential gene expression yet, functional characterization of the genes specifically induced and study of their expression control, is still in its infancy. Study of senescence-specific genes is required to allow identification of regulatory elements participating in senescence-induced expression and thus provide insights into the genetic regulation of senescence. A main feature of senescence is the hydrolysis of macromolecules by hydrolases of various types such as RNases and proteases. This study was aimed a analysis of senescence-inducible RNases in tomato with the following objectives: Isolation of senescence-inducible RNase cDNA clones; Expression analyses of RNase genes during senescence; Identification of sequences required for senescence-induced gene expression; Functional analyses of senescence-inducible RNases. We narrowed our aims somewhat to focus on the first three objectives because the budget we were awarded was reduced from that requested. We have expanded our research for identification senescence-related RNase/nuclease activities as we thought it will direct us to new RNase/nuclease genes. We have also carried out research in Arabidopsis and parsley, which enabled us to draw mire general conclusions. We completed the first and second objectives and have made considerable progress on the remaining two. We have defined growth conditions suitable for this research and defined the physiological and biochemical parameters characteristic to the advance of leaf senescence. In tomato and arabidopsis we have focused on natural leaf senescence. Parsley was used mainly for study of postharvest senescence in detached leaves. We have identified a 41-kD a tomato nuclease, LeNUCI, specifically induced during senescence which can degrade both RNA and DNA. This activity could be induced by ethylene in young leaves and was subjected to detailed analysis, which enabled its classification as Nuclease I enzyme. LeNUCI may be involved in nucleic acid metabolism during tomato leaf senescence. In parsley senescing leaves we identified 2 main senescence-related nuclease activities of 41 and 39-kDa. These activities were induced in both naturally or artificially senescing leaves, could degrade both DNA and RNA and were very similar in their characteristics to the LeNUCI. Two senescence-induced RNase cDNAs were cloned from tomato. One RNase cDNA was identical to the tomato LX RNase while the second corresponded to the LE RNase. Both were demonstrated before to be induced following phosphate starvation of tomato cell culture but nothing was known about their expression or function in plants. LX gene expression was much more senescence specific and ethylene could activate it in detached young leaves. LE gene expression, which could be transiently induced by wounding, appeared to be activated by abscisic acid. We suggest that the LX RNase has a role in RNA catabolism in the final stage of senescence, and LE may be a defense-related protein. Transgenic plants were generated for altering LX gene expression. No major visible alterations in the phenotype were observed so far. Detailed analysis of senescence in these plants is performed currently. The LX promoter was cloned and its analysis is performed currently for identification of senescence-specific regulatory elements. In Arabidopsis we have identified and characterized a senescence-associated nuclease 1 gene, BFN1, which is highly expressed during leaf and stem senescence. BFN1, is the first example of a senescence- associated gene encoding a nuclease I enzyme as well as the first nuclease I cloned and characterized from Arabidopsis. Our progress should provide excellent tools for the continued analysis of regulation and function of senescence-inducible ribonucleases and nucleases in plants. The cloned genes can be used in reverse genetic approaches, already initiated, which can yield a more direct evidence for the function of these enzymes. Another contribution of this research will be in respect to the molecular mechanism, which controls senescence. We had already initiated in this project and will continue to identify and characterize regulatory elements involved in senescence-specific expression of the genes isolated in this work.
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Gelb, Jr., Jack, Yoram Weisman, Brian Ladman e Rosie Meir. Identification of Avian Infectious Brochitis Virus Variant Serotypes and Subtypes by PCR Product Cycle Sequencing for the Rational Selection of Effective Vaccines. United States Department of Agriculture, dicembre 2003. http://dx.doi.org/10.32747/2003.7586470.bard.
Abstract (sommario):
Objectives 1. Determine the serotypic identities of 40 recent IBV isolates from commercial chickens raised in the USA and Israel. 2. Sequence all IBV field isolates using PCR product cycle sequencing and analyze their S 1 sequence to detennine their homology to other strains in the Genbank and EMBL databases. 3. Select vaccinal strains with the highest S 1 sequence homology to the field isolates and perform challenge of immunity studies in chickens in laboratory trials to detennine level of protection afforded by the vaccines. Background Infectious bronchitis (IB) is a common, economically important disease of the chicken. IB occurs as a respiratory form, associated with airsacculitis, condemnation, and mortality of meat-type broilers, a reproductive form responsible for egg production losses in layers and breeders, and a renal form causing high mortality in broilers and pullets. The causative agent is avian coronavirus infectious bronchitis virus (IBV). Replication of the virus' RNA genome is error-prone and mutations commonly result. A major target for mutation is the gene encoding the spike (S) envelope protein used by the virus to attach and infect the host cell. Mutations in the S gene result in antigenic changes that can lead to the emergence of variant serotypes. The S gene is able to tolerate numerous mutations without compromising the virus' ability to replicate and cause disease. An end result of the virus' "flexibility" is that many strains of IBV are capable of existing in nature. Once formed, new mutant strains, often referred to as variants, are soon subjected to immunological selection so that only the most antigenically novel variants survive in poultry populations. Many novel antigenic variant serotypes and genotypes have been isolated from commercial poultry flocks. Identification of the field isolates of IBV responsible for outbreaks is critical for selecting the appropriate strain(s) for vaccination. Reverse transcriptase polymerase chain reaction (RT-PCR) of the Sl subunit of the envelope spike glycoprotein gene has been a common method used to identify field strains, replacing other time-consuming or less precise tests. Two PCR approaches have been used for identification, restriction fragment length polymorphism (RFLP) and direct automated cycle sequence analysis of a diagnostically relevant hypervariab1e region were compared in our BARD research. Vaccination for IB, although practiced routinely in commercial flocks, is often not protective. Field isolates responsible for outbreaks may be unrelated to the strain(s) used in the vaccination program. However, vaccines may provide varying degrees of cross- protection vs. unrelated field strains so vaccination studies should be performed. Conclusions RFLP and S1 sequence analysis methods were successfully performed using the field isolates from the USA and Israel. Importantly, the S1 sequence analysis method enabled a direct comparison of the genotypes of the field strains by aligning them to sequences in public databases e.g. GenBank. Novel S1 gene sequences were identified in both USA and Israel IBVs but greater diversity was observed in the field isolates from the USA. One novel genotype, characterized in this project, Israel/720/99, is currently being considered for development as an inactivated vaccine. Vaccination with IBV strains in the US (Massachusetts, Arkansas, Delaware 072) or in Israel (Massachusetts, Holland strain) provided higher degrees of cross-protection vs. homologous than heterologous strain challenge. In many cases however, vaccination with two strains (only studies with US strains) produced reasonable cross-protection against heterologous field isolate challenge. Implications S1 sequence analysis provides numerical similarity values and phylogenetic information that can be useful, although by no means conclusive, in developing vaccine control strategies. Identification of many novel S1 genotypes of IBV in the USA is evidence that commercial flocks will be challenged today and in the future with strains unrelated to vaccines. In Israel, monitoring flocks for novel IBV field isolates should continue given the identification of Israel/720/99, and perhaps others in the future. Strains selected for vaccination of commercial flocks should induce cross- protection against unrelated genotypes. Using diverse genotypes for vaccination may result in immunity against unrelated field strains.