Littérature scientifique sur le sujet « Various liquid systems »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Sommaire
Consultez les listes thématiques d’articles de revues, de livres, de thèses, de rapports de conférences et d’autres sources académiques sur le sujet « Various liquid systems ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Articles de revues sur le sujet "Various liquid systems"
1
Rao, M. Raja, et C. Venkata Rao. « Ternary liquid equilibria. IV. Various systems ». Journal of Applied Chemistry 7, no 12 (4 mai 2007) : 659–66. http://dx.doi.org/10.1002/jctb.5010071204.
Texte intégral
2
Ze-Mu, Yu, Zhao Yu-Guang et Wang Er-Kang. « Electrochemical Investigation of Liquid/Liquid Systems Using Various Organic Solvents ». Acta Physico-Chimica Sinica 7, no 02 (1991) : 152–57. http://dx.doi.org/10.3866/pku.whxb19910205.
Texte intégral
3
Kim, Sun-Min, et Kwang-Yong Kim. « Performance Evaluation of Various Liquid-Jet Cooling Systems ». Numerical Heat Transfer, Part A : Applications 65, no 10 (14 mars 2014) : 987–1006. http://dx.doi.org/10.1080/10407782.2013.850961.
Texte intégral
4
Liu, Yang, Yuan-qi Feng et Yongjie Zhao. « Liquid–Liquid Equilibrium of Various Aqueous Two-Phase Systems : Experiment and Correlation ». Journal of Chemical & ; Engineering Data 58, no 10 (23 septembre 2013) : 2775–84. http://dx.doi.org/10.1021/je400453b.
Texte intégral
5
SHRIMALI, M. K., et R. S. JANGID. « A COMPARATIVE STUDY OF PERFORMANCE OF VARIOUS ISOLATION SYSTEMS FOR LIQUID STORAGE TANKS ». International Journal of Structural Stability and Dynamics 02, no 04 (décembre 2002) : 573–91. http://dx.doi.org/10.1142/s0219455402000725.
Texte intégralRésumé :
A comparative study of performance of various isolation systems for liquid storage tanks is investigated under real earthquake ground motions. The various base isolation systems considered are the laminated rubber bearings (with and without lead core) and sliding isolation systems (with and without restoring force). The isolated liquid storage tank is idealized with three-degrees-of-freedom associated with convective, impulsive and rigid mass under uni-directional earthquake excitation. Since the force-deformation behaviour of the isolation systems is non-linear, as a result, the equations of motion are solved numerically by step-by-step method. In order to measure the effectiveness of the isolation systems, the seismic response of the isolated liquid storage tanks is compared with the corresponding response of non-isolated tanks. Further, the effectiveness of the isolation is also explored for wide range of practical liquid storage tanks considering the influence of tank aspect ratio. It is observed that the isolation systems are quite effective in attenuating the earthquake acceleration transmitted to the tank, which reduces the design seismic forces significantly. Further, it is also found that the sliding type isolation systems are more effective in controlling the response of liquid storage tanks in comparison to the elastomeric bearings. Among the various sliding systems, the resilient-friction base isolator is found to be most effective for seismic isolation of the tanks.
6
Botsoglou, N. A., D. J. Fletouris, E. J. Simeonidou et I. E. Psomas. « Retention behavior of multiple sulfonamides in various liquid chromatographic systems ». Chromatographia 46, no 9-10 (novembre 1997) : 477–82. http://dx.doi.org/10.1007/bf02496364.
Texte intégral
7
Kubiczek, Artur, et Władysław Kamiński. « Liquid-Liquid Extraction in Systems Containing Butanol and Ionic Liquids – A Review ». Chemical and Process Engineering 38, no 1 (1 mars 2017) : 97–110. http://dx.doi.org/10.1515/cpe-2017-0008.
Texte intégralRésumé :
AbstractRoom-temperature ionic liquids (RTILs) are a moderately new class of liquid substances that are characterized by a great variety of possible anion-cation combinations giving each of them different properties. For this reason, they have been termed as designer solvents and, as such, they are particularly promising for liquid-liquid extraction, which has been quite intensely studied over the last decade. This paper concentrates on the recent liquid-liquid extraction studies involving ionic liquids, yet focusing strictly on the separation of n-butanol from model aqueous solutions. Such research is undertaken mainly with the intention of facilitating biological butanol production, which is usually carried out through the ABE fermentation process. So far, various sorts of RTILs have been tested for this purpose while mostly ternary liquid-liquid systems have been investigated. The industrial design of liquid-liquid extraction requires prior knowledge of the state of thermodynamic equilibrium and its relation to the process parameters. Such knowledge can be obtained by performing a series of extraction experiments and employing a certain mathematical model to approximate the equilibrium. There are at least a few models available but this paper concentrates primarily on the NRTL equation, which has proven to be one of the most accurate tools for correlating experimental equilibrium data. Thus, all the presented studies have been selected based on the accepted modeling method. The reader is also shown how the NRTL equation can be used to model liquid-liquid systems containing more than three components as it has been the authors’ recent area of expertise.
8
An, V. V., A. A. Ershov, Ch M. Mitypov et B. B. Damdinov. « Bulk viscosity in liquids and in liquid dispersed systems ». Izvestiya vysshikh uchebnykh zavedenii. Fizika, no 5 (2022) : 73–79. http://dx.doi.org/10.17223/00213411/65/5/73.
Texte intégralRésumé :
The paper provides a brief review of studies of the bulk viscosity of liquids and liquid dispersed systems. Obtaining experimental data on the viscosity of liquid dispersed (colloidal) systems is complicated by a number of factors: the difficulty of creating monodisperse systems, various methodological problems of accurately measuring the size of particles, their concentration, degree of homogeneity, and distribution. And also the difficulty lies in the fact that with an increase in the concentration of particles, a liquid dispersed system from a Newtonian liquid becomes non-Newtonian. The absorption of acoustic waves in a liquid is associated with both shear and bulk viscosity. It is shown that in most cases the value of bulk viscosity is much higher than the value of shear viscosity, and their ratio changes with increasing temperature. The data obtained on the basis of the Stokes model of absorption of sound waves are considered.
9
Suzuki, Nobuo, Kiyoki Satoh, Hidetoshi Shoji et Hisanori Imura. « Liquid-liquid extraction behavior of arsenic(III), arsenic(V), methylarsonate and dimethylarsinate in various systems ». Analytica Chimica Acta 185 (1986) : 239–48. http://dx.doi.org/10.1016/0003-2670(86)80051-4.
Texte intégral
10
Flieger, Jolanta, Joanna Feder-Kubis et Małgorzata Tatarczak-Michalewska. « Chiral Ionic Liquids : Structural Diversity, Properties and Applications in Selected Separation Techniques ». International Journal of Molecular Sciences 21, no 12 (15 juin 2020) : 4253. http://dx.doi.org/10.3390/ijms21124253.
Texte intégralRésumé :
Ionic liquids (ILs) are chemical compounds composed of ions with melting points below 100 °C exhibiting a design feature. ILs are commonly used as the so-called green solvents, reagents or highly efficient catalysts in varied chemical processes. The huge application potential of ionic liquids (IL) justifies the growing interest in these compounds. In the last decade, increasing attention has been devoted to the development of new methods in the synthesis of stable chiral ionic liquids (CILs) and their application in various separation techniques. The beginnings of the successful use of CILs to separate enantiomers date back to the 1990 s. Most chiral ILs are based on chiral cations or chiral anions. There is also a limited number of CILs possessing both a chiral cation and a chiral anion. Due to the high molecular diversity of both ions, of which at least one has a chiral center, we have the possibility to design a large variety of optically active structures, thus expanding the range of CIL applications. Research utilizing chiral ionic liquids only recently has become more popular. However, it is the area that still has great potential for future development. This review aimed to describe the diversity of structures, properties and examples of applications of chiral ionic liquids as new chiral solid materials and chiral components of the anisotropic environment, providing chiral recognition of enantiomeric analytes, which is useful in liquid chromatography, countercurrent chromatography and other various CIL-based extraction techniques including aqueous biphasic (ABS) extraction systems, solid–liquid two-phase systems, liquid–liquid extraction systems with hydrophilic CILs, liquid–liquid extraction systems with hydrophobic CILs, solid-phase extraction and induced-precipitation techniques developed in the recent years. The growing demand for pure enantiomers in the pharmaceutical and food industries sparks further development in the field of extraction and separation systems modified with CILs highlighting them as affordable and environmentally friendly both chiral selectors and solvents.
Thèses sur le sujet "Various liquid systems"
1
Bhattacharjee, Arijit. « Physico-chemical investigation on molecular interactions occurring in various liquid systems ». Thesis, University of North Bengal, 2010. http://hdl.handle.net/123456789/1319.
Texte intégral
2
Herron, William. « Mass transfer relationships for various gas-liquid systems ». Thesis, Queen's University Belfast, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359053.
Texte intégral
3
Sah, Radhey Shyam. « Studies on various interactions in some industrial important liquid systems ». Thesis, University of North Bengal, 2011. http://hdl.handle.net/123456789/1382.
Texte intégral
4
Sinha, Anuradha. « Investigation on viscous synergy and antagonism of some liquid mixtures and ion-solvent interaction of some compounds in various solvent systems ». Thesis, University of North Bengal, 2006. http://hdl.handle.net/123456789/705.
Texte intégral
5
Alex, Ansu. « Comparison study of various current and potential liquid biofuels in road freight transport : Application on a case study on Transport Centralen in Halmstad ». Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-33914.
Texte intégralRésumé :
The role of liquid biofuels in transportation to minimize the effects of climate change is evident and has led to a number of studies on finding effective solutions to replace fossil fuels. Liquid biofuels are especially important for heavy duty transports as the effective ‘green’ alternatives are not as many compared to light duty vehicles; for which for e.g. electrification is an option. This thesis presents a comparison study of 8 liquid biofuels with a total of 13 different fuel pathways for use in road freight transports; both current and potential future fuels are assessed in terms of their environmental effects, fuel properties and compatibility with the heavy duty vehicle engines (see Table 10, page 36). Furthermore, a case study is performed to assess the practicality of the results of the study. Hydro-treated vegetable oil, Bio Dimethyl ether, Liquefied Bio Methane/ ED95 are identified as fuels with considerable potential in the shorter term. Algal biofuel and Biomass to liquid (BTL) fuels from synthesis gas, if realized commercially would be a breakthrough for biofuels in overall transportation sector. However, life cycle analysis has to be performed for the different fuel pathways to completely understand the various impacting factors.
6
Sarkar, Lovely. « Physico-chemical studies on various interactions in some industrial solvent systems and viscous synergy and antagonism prevailing in liquid mixtures ». Thesis, University of North Bengal, 2010. http://hdl.handle.net/123456789/1418.
Texte intégral
7
Wang, Tongwen. « Hyphenated HPLC-MS technique for analysis of compositional monosaccharides of transgenic corn glycoprotein and characterization of degradation products of diazinon, fonofos and aldicarb in various oxidation systems ». Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/WangTongwen_09007dcc804e975c.pdf.
Texte intégralRésumé :
Thesis (Ph. D.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 23, 2008) Includes bibliographical references.
8
Datta, Biswajit. « Exploration of miscellaneous interfaces of some ionic solids and ionic liquids Prevailing in various solvent systems by the process of psysicochemical contrivance ». Thesis, University of North Bengal, 2017. http://ir.nbu.ac.in/handle/123456789/2673.
Texte intégral
9
Tshibangu, Mulamba Marc. « High pressure vapour-liquid equilibrium data of fluorochemical systems for various temperatures using a new static apparatus ». Thesis, 2010. http://hdl.handle.net/10413/2859.
Texte intégralRésumé :
The thermodynamic knowledge of accurate phase equilibrium data plays an important role in the design and optimization of separation processes in chemical and engineering industries. Vapour-liquid equilibrium data are essential for the design of efficient separation processes such as distillation. The presented research study is mainly focused on the vapour-liquid equilibrium data measurement of fluorochemical and hydrocarbon binary systems at various temperatures and at high pressures. A new static analytical apparatus was constructed and commissioned for the measurement of accurate and precise vapour-liquid equilibrium data at temperatures and absolute pressures ranging from low temperatures to 323.15 K and 0 to 10 MPa respectively. The new apparatus incorporates the ROLSI TM sampler, a sampling technique developed by the CEP/TEP laboratory in Fontainebleau, France. Isothermal high pressure VLE data were measured for three binary systems comprising of hexafluoroethane (R116) + propane, HFPO + propane and ethane + octafluoropropane (R218). The R116 + propane system at 263.15 K was measured as a test system using the new static apparatus. These measurements helped to confirm the functioning of the experimental apparatus. The reliability and the reproducibility of the experimental procedure were also checked. The data obtained were in excellent agreement with data in the literature. Thereafter, measurements of previously unmeasured systems were undertaken. Isothermal vapour-liquid equilibrium data measurements for the ethane + octafluoropropane system were performed at five isotherms with temperatures and pressures ranging from 264.05 to 308.04 K and 0.298 to 4.600 MPa respectively. The five isotherms constitute new experimental data. The HFPO + propane system was also investigated and vapour-liquid equilibrium data were measured at three isotherms (283.05, 303.05 and 323.05 K) with pressures ranging from 0.437 to 2.000 MPa. The data measured also constitute a set of a new HPVLE data. The uncertainties in the measurement for both systems were within ± 0.09 K, ± 0.0016 MPa and less than 2% for temperatures, pressures and mole fractions, respectively. All experimental data were correlated via the direct method using the Peng-Robinson equation of state with the Mathias-Copeman alpha function and the Wong-Sandler mixing rules incorporating the NRTL activity coefficient model. The consistency of the measured VLE data was tested using the Van Ness point test which yielded few points of difference between the measured and calculated data, suggesting a low error rate.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.
10
Chattopadhyay, Jayeeta. « Activity induced phase separation and the emergence of liquid crystal phases in chiral and achiral systems, and development of an efficient method to compute the entropy of various liquid crystal phases ». Thesis, 2023. https://etd.iisc.ac.in/handle/2005/6168.
Texte intégralRésumé :
The phase behaviour of shape-anisotropic particles is an emerging field of research that
gives rise to various liquid crystal phases. In this thesis, we explore various equilibrium and
non-equilibrium properties of shape-anisotropic particles by modelling them as soft repulsive
spherocylinders (SRSs) and soft helical rods.
In the first part, we introduce the two-temperature model to study the phase behaviour of
scalar active SRS and soft helical rods. Most realisations of activity are vectorial in nature due
to the force of self-propulsion. Recent studies have shown that many physical and biological
processes, like phase separation in colloidal systems, chromatin organisation in the nucleus,
are operated by the unequal sharing of energy by the constituents of the system. Such systems
are classified as scalar active systems. In the simplest case, these systems can be modelled by
connecting half the particles with a thermostat of higher temperature (labelled ‘hot’/‘active’)
while maintaining temperature of the rest constant (labelled ‘cold’/‘passive’) at a lower value.
The relative temperature difference between the two constituents of the system is a measure
of activity. This model is known as two-temperature model that has been found to capture
many essential properties of scalar activity. Starting from a homogeneous isotropic phase at
a definite temperature, we show that this model leads to phase separation into hot and cold
regions and induces liquid-crystal ordering of the cold particles while hot particles remain in
the isotropic phase. In particular, we find that activity drives the cold particles through a phase
transition to a more ordered state and the hot particles to a state of less order compared to
the initial equilibrium state. Hence, the phase boundary of the isotropic-nematic transition
shifts towards lower densities for cold particles and higher densities for the hot particles with
respect to its equilibrium location. Remarkably, we find liquid crystalline phases for the aspect
ratios [length(L)/diameter(D)] as low as L/D = 2, 3 which do not satisfy the minimum
shape-anisotropy criteria that Onsager’s theory demands in equilibrium. Similar model we
have employed in a system of soft helical particles of various intrinsic chiralities and found different liquid crystal ordering in these cases as well. The following nonequilibrium features
emerge from our study: an enhancement of the temperature of half of the particles gives rise
to LC ordering in the remaining half of the particles at any density. The hot and cold domains
should not be viewed as bulk equilibrium phases with non-equilibrium behaviour only at the interfaces.
By calculating the stress anisotropy and heat current, we find that the non-equilibrium
behaviour is not restricted to the hot-cold interfaces but pervades the system as a whole, driving
various ordering transitions in the cold zone. Thus, our study unravels various aspects of
non-equilibrium scalar active rods in the framework of the two-temperature model.
In the second part, we discuss the Two-phase thermodynamic (2PT) model for computing
entropy, free energy, and other thermodynamic properties of various liquid crystal phases in
equilibrium. In the 2PT method, the density of state (DoS) of the LC phases is decomposed
into vibrational (solid) and diffusive (gas) components. The thermodynamic quantities are
then calculated using harmonic oscillator approximations for the solid component, hard sphere
approximations for the gas component, and the rigid rotor approximation for the rotational
mode. In the 2PT method, the entropy of a definite state point is calculated from a single
MD trajectory, which makes it advantageous for systems for which the analytical form of the
equation of state is unknown (such as SRS). Our method can be used to calculate entropy and
other thermodynamic quantities of different liquid crystal phases formed by the SRS system.Inspire fellowship
Livres sur le sujet "Various liquid systems"
1
Titenok, Aleksandr, V. Sidoro et A. V. Kirichek. Ensuring the operational reliability of mechanical systems. ru : INFRA-M Academic Publishing LLC., 2022. http://dx.doi.org/10.12737/1096388.
Texte intégralRésumé :
The textbook discusses the nomenclature, performance characteristics and quality indicators of fuels, lubricants and special liquids that affect the technical and economic performance of machines.
An analytical approach to the study of the development of a technical project is proposed.
Meets the requirements of the federal state educational standards of higher education of the latest generation.
It is intended for students of engineering specialties of all forms of education, students of the system of advanced training and vocational training, undergraduates and postgraduates, specialists in the field of various transport and technological processes and means of their implementation.
2
Aveyard, Bob. Surfactants. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198828600.001.0001.
Texte intégralRésumé :
Characteristically, surfactants in aqueous solution adsorb at interfaces and form aggregates (micelles of various shapes and sizes, microemulsion droplets, and lyotropic liquid crystalline phases). This book is about the behaviour of surfactants in solution, at interfaces, and in colloidal dispersions. Adsorption at liquid/fluid and solid/liquid interfaces, and ways of characterizing the adsorbed surfactant films, are explained. Surfactant aggregation in systems containing only an aqueous phase and in systems with comparable volumes of water and nonpolar oil are each considered. In the latter case, the surfactant distribution between oil and water and the behaviour of the resulting Winsor systems are central to surfactant science and to an understanding of the formation of emulsions and microemulsions. Surfactant layers on particle or droplet surfaces can confer stability on dispersions including emulsions, foams, and particulate dispersions. The stability is dependent on the surface forces between droplet or particle surfaces and the way in which they change with particle separation. Surface forces are also implicated in wetting processes and thin liquid film formation and stability. The rheology of adsorbed films on liquids and of bulk colloidal dispersions is covered in two chapters. Like surfactant molecules, small solid particles can adsorb at liquid/fluid interfaces and the final two chapters focus on particle adsorption, the behaviour of adsorbed particle films and the stabilization of Pickering emulsions.
3
Schrijver, Karel. Exploring the Solar System. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198799894.003.0003.
Texte intégralRésumé :
In this chapter, the author summarizes the properties of the Solar System, and how these were uncovered. Over centuries, the arrangement and properties of the Solar System were determined. The distinctions between the terrestrial planets, the gas and ice giants, and their various moons are discussed. Whereas humans have walked only on the Moon, probes have visited all the planets and several moons, asteroids, and comets; samples have been returned to Earth only from our moon, a comet, and from interplanetary dust. For Earth and Moon, seismographs probed their interior, whereas for other planets insights come from spacecraft and meteorites. We learned that elements separated between planet cores and mantels because larger bodies in the Solar System were once liquid, and many still are. How water ended up where it is presents a complex puzzle. Will the characteristics of our Solar System hold true for planetary systems in general?
4
Pang, Changhyun, Chanseok Lee, Hoon Eui Jeong et Kahp-Yang Suh. Skin and dry adhesion. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199674923.003.0022.
Texte intégralRésumé :
Close observation of various attachment systems in animal skins has revealed various exquisite multi-scale architectures for essential functions such as locomotion, crawling, mating, and protection from predators. Some of these adhesion systems of geckos and beetles have unique structural features (e.g. high-aspect ratio, tilted angle, and hierarchical nanostructure), resulting in mechanical interlocking mediated by van der Waals forces or liquid secretion (capillary force). In this chapter, we present an overview of recent advances in bio-inspired, artificial dry adhesives, and biomimetics in the context of nanofabrication and material properties. In addition, relevant bio-inspired structural materials, devices (clean transportation device, interlocker, biomedical skin patch, and flexible strain-gauge sensor) and microrobots are briefly introduced, which would shed light on future smart, directional, and reversible adhesion systems.
5
Pistor, Katharina. Moneys’ legal hierarchy. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198755661.003.0008.
Texte intégralRésumé :
This chapter discusses the way in which money is legally constructed and hierarchically structured. In financial markets, participants trade different forms of money, some of which is state-issued and some privately issued. A form of money is closer to the “apex” of the system the closer it is to entities that can issue liquid means or determine acceptable forms of payment, such as central banks and governments. During financial crises, market participants close to the “apex” are systematically advantaged. Various legal devices, e.g. property rights, collateral rights, or trust law, contribute to hierarchically structuring the financial system, by granting preferential treatment to some moneys over others. As the historical development of money shows, public and private entities have been closely intertwined in its creation. These legal constructions reveal questions of justice at the very core of the financial system, with regard to both unchecked hierarchies and unjustified distributions of losses.
Chapitres de livres sur le sujet "Various liquid systems"
1
Werzner, Eric, Miguel A. A. Mendes, Cornelius Demuth, Dimosthenis Trimis et Subhashis Ray. « Simulation of Fluid Flow, Heat Transfer and Particle Transport Inside Open-Cell Foam Filters for Metal Melt Filtration ». Dans Multifunctional Ceramic Filter Systems for Metal Melt Filtration, 301–33. Cham : Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-40930-1_13.
Texte intégralRésumé :
AbstractIn order to develop improved filters for metal melt filtration, different physical phenomena that take place during depth filtration of liquid metals need to be well understood. Due to the difficult accessibility of the process, the harsh process conditions and the randomness of the typically employed ceramic foam filters, representative experimental investigations are extremely difficult to perform and often provide only integral quantities or selective information. This chapter presents a numerical model for simulating the depth filtration of liquid metal at the pore-scale, i.e., fully resolving the complex filter geometry, which can also accurately handle the curved filter walls. In the model, the velocity and pressure distribution of the melt flow is obtained by the lattice-Boltzmann method and the temperature field is calculated using the finite volume method, while the transport and filtration of the inclusions are predicted by solving the equation of motion for particles in a Lagrangian reference frame. In order to obtain a consistent representation of the curved filter walls for both particle transport and fluid flow, the Euclidean distance field of the filter structures is employed. By comprehensive parametric studies, the sensitivity of the filtration process with respect to various geometric parameters and process conditions is investigated. Therefore, geometries of conventionally manufactured filters, acquired from 3D μCT scanning, as well as computer-generated filter structures are considered. Their performance is assessed by evaluating various effective properties, such as the viscous and inertial permeability and the filtration coefficient. The numerical predictions allow to draw conclusions with respect to the dominant physical mechanisms and are compared with those from simplified physical models, which are shown to be sufficiently accurate for the pre-screening of filters. On the basis of the detailed results, suggestions for improved filter geometries are made, depending on the considered filtration process. Further, simplified models for the prediction of the effective thermal conductivity of open-cell foams in presence and absence of radiation are presented and validated using the detailed numerical predictions.
2
Giovenale, Anna Maria. « From a Liquid Society, Through Technological Imagination, to Beyond the Knowledge Society ». Dans The Urban Book Series, 1–9. Cham : Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-29515-7_1.
Texte intégralRésumé :
AbstractThe paper aims to introduce the Proceedings of the Conference “Technological Imagination in the Green and Digital Transition”, starting from the initial idea. The Scientific Community has been invited to propose visions of technological imagination, in a time of great uncertainty and fragility, so that they could be subjected to a highly interesting analysis. The theme of “fragile” cities and habitats highlights the necessary transition from liquid society beyond the knowledge society. For the purposes of conference, it was noted that these themes, each with its own in-depth considerations, are to be found, thanks to the different contributions, in all of the various sessions. The Conclusions are to upgrade national and international research systems and to change the training modalities.
3
Fankhänel, Beate, Ekaterina Schmid et Michael Stelter. « Influence of Reactive Filter Materials on Casting’s Quality in Aluminum Casting ». Dans Multifunctional Ceramic Filter Systems for Metal Melt Filtration, 215–39. Cham : Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-40930-1_9.
Texte intégralRésumé :
AbstractThis chapter presents the most important results of investigations on reactive filter materials for the purification of aluminum melts. Reactive filter materials were developed with the aim to remove impurities dissolved in the melt, such as hydrogen from liquid aluminum, by means of specific chemical interactions between the molten metal and the filter material. Selected ceramic foam filters, consisting of carbon-free and carbon-bonded ceramics, were used in their uncoated state as well as treated with various coatings. Numerous fundamental studies were carried out to evaluate the applicability of the new filter materials: sessile-drop-experiments, immersion and filtration tests, the metallographic evaluation of the used filters and the metal samples retrieved from these experiments. Interfacial reactions and the purity of the treated melts were determined with the help of these experiments, following microstructural analyses to obtain indications for the filtration properties and the potential chemical reactions between the filter material and the melt. As a result, it was possible to determine that spodumene, LiAl(Si2O6), positively influences the hydrogen porosity of aluminum castings when applied as a reactive filter material. Filtration alone already helps to prevent areas of increased macroporosity by calming the melt flow, but filter materials containing spodumene further affect microporosity in the castings in positive ways.
4
Mehta, Ruchika, Sunil Kumar Singla et Swati Sondhi. « Fractional System Modeling of Liquid–Liquid Heat Exchanger Using Various Optimization Techniques ». Dans Lecture Notes in Mechanical Engineering, 435–44. Singapore : Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2188-9_40.
Texte intégral
5
Abendroth, Martin, Shahin Takht Firouzeh, Meinhard Kuna et Bjoern Kiefer. « Determination of the Temperature-Dependent Fracture and Damage Properties of Ceramic Filter Materials from Small Scale Specimens ». Dans Multifunctional Ceramic Filter Systems for Metal Melt Filtration, 577–603. Cham : Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-40930-1_23.
Texte intégralRésumé :
AbstractOpen cell ceramic foam filters are used to improve the quality of metallic cast products. They play a major role on reducing the number of inclusions within the microstructure of the cast product and restraining the liquid flow inside the mold. The newly developed carbon-bonded alumina ceramics are investigated considering the mechanical and thermal loads of the filtration process. The aim of this project is to assess the strength, the fracture mechanical behavior, and the damage properties of the filter material. Since the tiny struts of the foam have different properties than the common bulk material specimen, small specimens of millimeter size are needed. Within this work, a combination of experiments and numerical simulations are conducted for various mechanical tests at temperatures up to 1500 $${}^{\circ }\text {C}$$ ∘ C . The first test is the small punch test (SPT), where a small disk-like specimen is supported on a circular die and loaded with a spherical tipped punch until failure of the disk occurs. The small punch fracture stress is obtained from the experiments, as well as the corresponding parameters of the Weibull distribution necessary for the evaluation of the cold modulus of rupture (CMOR). Furthermore, a modified version of the SPT, the so called ball on three ball test (B3B), is carried out. In the B3B test, miniaturized disk-shaped specimens are supported with three spherical balls and loaded with a spherical tipped punch until failure. Hereby, the fracture mechanical parameters, such as the fracture toughness, are identified with the help of numerical simulations. Moreover, the Chevron notched beam test (CNB) is used to determine the fracture toughness of the ceramics. The final test is the Brazilian disc test (BDT), where compressive loads are exerted on the specimen leading to tensile stresses along the specimen diameter, perpendicular to the applied load direction. This test is employed to determine the Young’s modulus, the yield stress and the fracture toughness. In general the simplicity of all these tests, their setup, application, and results evaluation, in addition to the ease of specimens production, make them very attractive. The size of these specimens is about one order of magnitude smaller than that of common standard tests. The accompanying numerical simulations are inevitable to extract from the measurements the wanted mechanical properties.
6
Song, Wei, Zilong Zhu, Zhong Wan, Chan Long et Tao Liu. « Brief Review and Technical Insight of Liquefied Hydrogen Carriers Development ». Dans Proceedings of the 10th Hydrogen Technology Convention, Volume 1, 151–62. Singapore : Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-8631-6_17.
Texte intégralRésumé :
AbstractCountries worldwide are shifting to a hydrogen economy in response to stringent environmental regulations, and hydrogen transport between countries is expected to increase in the medium to long term. Although hydrogen is traded between countries in different forms such as ammonia, liquid hydrogen, and methanol, from the perspective of volume density and production/demand area without a separate process, the transportation of hydrogen in liquid form is the potential way for large-scale transportation of hydrogen in the future. This article aims to highlight the opportunities and challenges technical for the ocean-going liquid hydrogen carriers. An overview of development state-of-the-art and key technical challenges of liquid hydrogen carrier ships are summarized, including regulation, the cargo containment structure and insulation, boil off ratio (BOR) evaluation, boil-off gas (BOG) handling system and propulsion system. Finally, detailed technical route of the key technology required by future liquid hydrogen carrier is extrapolated, and securing a possible design through various technological alternatives.
7
Aiman, Y., N. F. Azman et S. Syahrullail. « Tribological Test of Composites Material Lubricated with Various Solid-Liquid Lubricating System ». Dans Tribological Applications of Composite Materials, 71–97. Singapore : Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-9635-3_3.
Texte intégral
8
Eremin, Sergey. « Immunochemical methods for detection of organophosphorus compounds ». Dans ORGANOPHOSPHORUS NEUROTOXINS, 219–30. ru : Publishing Center RIOR, 2020. http://dx.doi.org/10.29039/33_219-230.
Texte intégralRésumé :
Organophosphorus compounds (OP) are found in environmental objects and food products. Due to their high toxicity and inhibition of cholinesterase activity, it is necessary to control residual amounts of OP. The most common methods for determining OP are gas and liquid chromatography with various detection methods. However, chromatographic analysis is lengthy, requires complex sample preparation and expensive equipment, which limits its use for screening a large number of samples and continuous monitoring of the content of OP. To detect the OP, it is necessary to use High Throughput Screening methods, using simple, fast and inexpensive analysis methods. Currently, immunochemical methods are increasingly used to determine OP. These methods are based on the recognition of the analyte (antigen) by specific receptors (antibodies) with the formation of the antigen-antibody complex and the measurement of the analytical signal generated by the immunochemical test system in response to complex formation, which leads to high sensitivity and specificity of the analysis.
9
Xia, Longgong, Zhihong Liu et Pekka Antero Taskinen. « Experimental Determination of the Liquidus Surface (1473 K) in Cu-ZnO-SiO2-O System at Various Oxygen Partial Pressures ». Dans Advances in Molten Slags, Fluxes, and Salts : Proceedings of the 10th International Conference on Molten Slags, Fluxes and Salts 2016, 971–78. Cham : Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-48769-4_103.
Texte intégral
10
Xia, Longgong, Longgong Xia, Zhihong Liu, Pekka Antero Taskinen et Pekka Antero Taskinen. « Experimental Determination of the Liquidus Surface (1473 K) in Cu-ZnO-SiO2-O System at Various Oxygen Partial Pressures ». Dans Advances in Molten Slags, Fluxes, and Salts, 971–78. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119333197.ch103.
Texte intégralActes de conférences sur le sujet "Various liquid systems"
1
Seo, Jeonghwa, Jeong-Bong Lee, Sang Kug Chung et Daeyoung Kim. « Magnetically-induced various recoverable deformation of miagnetic liquid metal marble ». Dans 2018 IEEE Micro Electro Mechanical Systems (MEMS). IEEE, 2018. http://dx.doi.org/10.1109/memsys.2018.8346504.
Texte intégral
2
Stefanitsis, Dionisis, Ilias Malgarinos, George Strotos, Nikolaos Nikolopoulos, Emmanouil Kakaras et Manolis Gavaises. « Numerical investigation of the aerodynamic breakup of diesel droplets under various gas pressures ». Dans ILASS2017 - 28th European Conference on Liquid Atomization and Spray Systems. Valencia : Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/ilass2017.2017.4690.
Texte intégralRésumé :
The present study investigates numerically the aerodynamic breakup of Diesel droplets for a wide range of ambient pressures encountered in engineering applications relevant to oil burners and internal combustion engines. The numerical model solves the Navier-Stokes equations coupled with the Volume of Fluid (VOF) methodology utilized for capturing the interface between the liquid and the surrounding gas. An adaptive local grid refinement technique is used to increase the accuracy of the numerical results around the interface. The Weber (We) numbers examined are in the range of 14 to 279 which correspond to bag, multimode and sheet-thinning breakup regimes. Model results are initially compared against published experimental data and show a good agreement in predicting the drop deformation and the different breakup modes. The predicted breakup initiation times for all cases lie within the theoretical limits given by empirical correlations based on the We number. Following the model validation, the effect of density ratio on the breakup process is examined by varying the gas density (or equivalently the ambient pressure), while the We number is kept almost constant equal to 270; ambient gas pressure varies from 1 up to 146bar and the corresponding density ratios (ε) range from 700 down to 5. Results indicate that the predicted breakup mode of sheet-thinning remains unchanged for changing the density ratio. Useful information about the instantaneous drag coefficient (Cd) and surface area as functions of the selected non-dimensional time is given. It is shown that the density ratio is affecting the drag coefficient, in agreement with previous numerical studies.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4690
3
Madavan R et Sujatha Balaraman. « Performance analysis of transformer liquid insulation system under various environmental conditions ». Dans 2015 International Conference on Condition Assessment Techniques in Electrical Systems (CATCON). IEEE, 2015. http://dx.doi.org/10.1109/catcon.2015.7449513.
Texte intégral
4
Hong, Wen, Longjun Tang, Bowen Ji, Wenxi Sun, Bin Yang, Xiaolin Wang et Jingquan Liu. « A Novel SESC Microstructure to Realize Various Spontaneously Liquid Spreading Properties ». Dans 2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2019. http://dx.doi.org/10.1109/memsys.2019.8870690.
Texte intégral
5
Nedospasov, I. A., V. G. Mozhaev et I. E. Kuznetsova. « Leaky backward Lamb waves in various isotropic and anisotropic plate/liquid systems ». Dans 2016 IEEE International Ultrasonics Symposium (IUS). IEEE, 2016. http://dx.doi.org/10.1109/ultsym.2016.7728566.
Texte intégral
6
Rimbert, Nicolas, M. Hadj-Achour et M. Gradeck. « Liquid-Liquid Secondary Fragmentation with Solidification ». Dans ILASS2017 - 28th European Conference on Liquid Atomization and Spray Systems. Valencia : Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/ilass2017.2017.5034.
Texte intégralRésumé :
In the event of a hypothetical core disruptive accident in nuclear power plants, the molten core may flow out thereactor vessel and interact with the cold water. The evolution of the accident is strongly affected by the fragmentation of the jet of molten metallic fuel due to its interaction with the water (i.e. this situation is known as fuel coolant interaction, FCI). In order to evaluate and predict the various consequences of a FCI, many researches are conducted with either corium or high melting temperature molten metal, where premixing stage evolves with an important production of steam. This steam production that is unavoidable because the high temperature of corium leads to difficulties for using optical diagnostics. Hence, in our case, we use a eutectic alloy (Field’s metal) with a low melting point (62°C) in order to be able to visualize correctly the droplet fragmentation processes.The present work focuses on the fragmentation of a single Field’s metal liquid droplet with mass equals to 0.27g (±0.01g). The liquid droplet interacts with a water pool whose temperature range between 20°C to 60°C. According to its Weber number, it fragments in different ways. For each experiment, a single droplet has been visualized using a high-speed camera (at 8000 fps). All measurements (drop size, velocity, impact parameter and geometrical properties of the drops after the penetration) into the pool are evaluated using an open source image processing. Solidified fragments can then be sieved and the size PDF determined. Focus of the present work is put on the evolution of the Sauter Mean Diameter with increasing Weber number and varying bath pool temperature. It is shown that using a simple crust model during solidification and defining an effective Weber number which include the crust elasticity all the curves collapse on the same master curve for all the water bathtemperature considered.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.5034
7
Kawano, Takeshi, Akihito Ikedo, Takahiro Kawashima, Kazuaki Sawada et Makoto Ishida. « Vertically Aligned Various Lengths Doped-Silicon Microwire Arrays by Repeated Selective Vapor-Liquid-Solid Growth ». Dans 2009 IEEE 22nd International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2009. http://dx.doi.org/10.1109/memsys.2009.4805485.
Texte intégral
8
Kuhnhenn, Maximilian, Max Frederik Luh, Tórstein Vincent Joensen, Ilia V. Roisman et Cameron Tropea. « Experimental Characterization of Spray generated by a Rotary Atomizer Wheel ». Dans ILASS2017 - 28th European Conference on Liquid Atomization and Spray Systems. Valencia : Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/ilass2017.2017.4610.
Texte intégralRésumé :
Rotary atomizers are widely used for spray drying processes to produce powders in various industrial applications.The atomization regime and therefore the droplet size distribution have a substantial impact on the process outcome. Depending on the intended use of the dried powder particles, various droplet size distributions are desired, which should be adjustable by the main operating parameters (e.g. mass flow rate and wheel speed). In this study the spray of a rotary atomizer wheel, operated under normal ambient conditions, is characterized for different mass flow rates, wheel speeds and viscosities with the help of a phase Doppler measurement system. Visual investigations of the spray with a high resolution camera system help to get a better understanding of the atomization process, aswell as the thickness of the liquid jets exiting the atomizer.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4610
9
Heydari, Ali, Pardeep Shahi, Vahideh Radmard, Bahareh Eslami, Uschas Chowdhury, Satyam Saini, Pratik Bansode, Harold Miyamura, Dereje Agonafer et Jeremy Rodriguez. « Liquid to Liquid Cooling for High Heat Density Liquid Cooled Data Centers ». Dans ASME 2022 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/ipack2022-97416.
Texte intégralRésumé :
Abstract Removal of heat is becoming a major challenge in today’s data centers. Computing-intensive applications such as artificial intelligence and machine learning are pushing data center to compute intensive systems, such as GPU, CPU, and switches to their extreme limits. Racks of IT can approach up to 100kW of heat dissipation challenging traditional data center designs for enterprises and cloud service providers. Direct-to-chip liquid cooling utilizing cold plates is becoming a common method of removing heat from high heat density data center server racks. There are various methods of applying liquid cooling to data centers to address the high heat density components such as liquid to liquid (L2L), liquid to air (L2A), and liquid to single phase refrigerant (L2R). This study aims to investigate the thermo-hydraulic performance of the L2L cooling systems using cooling distribution units (CDUs). CDUs provide a cold secondary coolant (Propylene Glycol 25%) into the cooling loops of liquid-cooled server racks, with the CDUs providing liquid to liquid heat exchange between the primary facility water and secondary liquid used for cold plates. This study uses Thermal Test Vehicles (TTVs) which have been built to reproduce and simulate high heat density servers. Four different cooling loops are characterized experimentally, and detailed analytical and numerical simulations using CFD are developed for analyzing the cooling characteristics of the entire L2L cooling loop, including the CDU, for removing heat from the cold plates. Detailed Flow Network Modeling (FNM) has been performed to analyze precise hydraulic modeling of the secondary fluid flow, from the CDUs to the cooling loops, for predicting pressure drop and flow rate of the secondary coolant. A FNM properly sizes the pumping requirements of the L2L cooling system. Additionally, a system calculator has been created for quickly sizing all secondary loop piping for L2L heat exchanger deployments.
10
Wang, Hua, Francisco Felis, Severine Tomas, Fabien Anselmet et Muriel Amielh. « An improved image processing method for particle characterization by shadowgraphy ». Dans ILASS2017 - 28th European Conference on Liquid Atomization and Spray Systems. Valencia : Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/ilass2017.2017.4614.
Texte intégralRésumé :
Shadowgraphy is one of the most popular imaging techniques to characterize moving particles by their size,geometry as well as velocity, due to its simplicity. However, it requires advanced image processing to handle various image defects such as non-uniform illumination, overlapped particles, etc., which are normally only solved for individual applications. This study proposes a robust image processing method for particle shadowgraphy, aiming to process imperfect particle shadow images. The proposed method first detects qualified particles from particle shadow images, and then processes detected particles individually. Therefore different defects from different particles can be handled separately and locally. An overlapped particles detection and separation algorithm is also implemented to improve the accuracy of size and geometry characterization.The proposed method is first proved by synthetic generated particle shadow images, followed by a proof test with shadow images from a transparent dot pattern target. Finally this method is successfully applied to a shadowimage acquired from a water spray and proved to be able to handle various issues of shadowgraphy.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4614
Rapports d'organisations sur le sujet "Various liquid systems"
1
Ward, Kyle, et Timothy Jacobs. PR-457-20204-R01 Pump Station Efficiency Improvement Evaluation. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), janvier 2021. http://dx.doi.org/10.55274/r0012006.
Texte intégralRésumé :
Pipeline transmission of liquids, although highly cost effective relative to other means of liquid transport (e.g., on-highway freight vehicles or trains), still encumbers costs with opportunities for improvement. Liquid pumps, serving as the prime mover for liquids in a pipeline, are a chief operating expense for pipeline transmission. A large and diverse set of pump characteristics - both in terms of style, motive force, and age -make it difficult to identify technologies that result in substantial cost savings for the owner / operator of liquid pipeline systems. Thus, characterizing and classifying the various liquid pump technologies, as well as identifying the latest advancements that can enable retrofit and / or new installation improvements for the purpose of reducing operational pump costs and downtime, is crucial. This study identifies the latest advancements that can increase pump efficiency, increase overall system efficiency, and allow for short-term and long-term cost savings.
2
Siebenaler. PR-015-084510-R01 Evaluation of External Leak Detection Systems for Liquid Pipelines. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), septembre 2009. http://dx.doi.org/10.55274/r0010674.
Texte intégralRésumé :
A project was conducted to determine the viability of various external leak detection systems for use on liquid pipelines.� This project defined external leak detection as a means of detecting unintended pipeline discharge without the use of pressure or flow modeling. Specifically, this project was focused on the ability to detect leaks that are too small for most computational pipeline monitoring (CPM) systems to detect.� A list of possible technologies was assembled and a tradeoff study was conducted to rank the technologies.
3
Siebenaler. PR-015-123713-R01 Field Testing of Negative-Wave Leak Detection Systems. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), juin 2013. http://dx.doi.org/10.55274/r0010788.
Texte intégralRésumé :
A field test was conducted to evaluate the ability of various negative-wave technologies to detect small leaks on liquid pipelines. A series of fluid withdrawals were conducted on a 41-km segment of a 30-inch diameter heavycrude pipeline. This report details the test setup, execution, and results.
4
Siebenaler. L52272 Detection of Small Leaks in Liquid Pipelines - Gap Study of Available Methods. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), février 2007. http://dx.doi.org/10.55274/r0010662.
Texte intégralRésumé :
The integrity of the liquid pipeline network in the United States is of concern to the pipeline operators, the surrounding communities, and the government. During a recent Office of Pipeline Safety industry forum, concerns regarding the detection of small liquid leaks were discussed. The important topic areas related to small leak detection included identifying the available real-time monitoring and detection systems, assessing the need for new detection technologies, and understanding the performance of currently available systems. The objective of the project was to assess the gap between what liquid pipeline operators need in terms of leak detection and what various leak detection technologies can provide, specifically related to small leaks. For this gap analysis study, small leaks were considered to be pipeline releases that were less than 5% of nominal pipeline flow rate.
5
Shmulevich, Itzhak, Shrini Upadhyaya, Dror Rubinstein, Zvika Asaf et Jeffrey P. Mitchell. Developing Simulation Tool for the Prediction of Cohesive Behavior Agricultural Materials Using Discrete Element Modeling. United States Department of Agriculture, octobre 2011. http://dx.doi.org/10.32747/2011.7697108.bard.
Texte intégralRésumé :
The underlying similarity between soils, grains, fertilizers, concentrated animal feed, pellets, and mixtures is that they are all granular materials used in agriculture. Modeling such materials is a complex process due to the spatial variability of such media, the origin of the material (natural or biological), the nonlinearity of these materials, the contact phenomenon and flow that occur at the interface zone and between these granular materials, as well as the dynamic effect of the interaction process. The lack of a tool for studying such materials has limited the understanding of the phenomena relevant to them, which in turn has led to energy loss and poor quality products. The objective of this study was to develop a reliable prediction simulation tool for cohesive agricultural particle materials using Discrete Element Modeling (DEM). The specific objectives of this study were (1) to develop and verify a 3D cohesionless agricultural soil-tillage tool interaction model that enables the prediction of displacement and flow in the soil media, as well as forces acting on various tillage tools, using the discrete element method; (2) to develop a micro model for the DEM formulation by creating a cohesive contact model based on liquid bridge forces for various agriculture materials; (3) to extend the model to include both plastic and cohesive behavior of various materials, such as grain and soil structures (e.g., compaction level), textures (e.g., clay, loam, several grains), and moisture contents; (4) to develop a method to obtain the parameters for the cohesion contact model to represent specific materials. A DEM model was developed that can represent both plastic and cohesive behavior of soil. Soil cohesive behavior was achieved by considering tensile force between elements. The developed DEM model well represented the effect of wedge shape on soil behavior and reaction force. Laboratory test results showed that wedge penetration resistance in highly compacted soil was two times greater than that in low compacted soil, whereas DEM simulation with parameters obtained from the test of low compacted soil could not simply be extended to that of high compacted soil. The modified model took into account soil failure strength that could be changed with soil compaction. A three dimensional representation composed of normal displacement, shear failure strength and tensile failure strength was proposed to design mechanical properties between elements. The model based on the liquid bridge theory. An inter particle tension force measurement tool was developed and calibrated A comprehensive study of the parameters of the contact model for the DEM taking into account the cohesive/water-bridge was performed on various agricultural grains using this measurement tool. The modified DEM model was compared and validated against the test results. With the newly developed model and procedure for determination of DEM parameters, we could reproduce the high compacted soil behavior and reaction forces both qualitatively and quantitatively for the soil conditions and wedge shapes used in this study. Moreover, the effect of wedge shape on soil behavior and reaction force was well represented with the same parameters. During the research we made use of the commercial PFC3D to analyze soil tillage implements. An investigation was made of three different head drillers. A comparison of three commonly used soil tillage systems was completed, such as moldboard plow, disc plow and chisel plow. It can be concluded that the soil condition after plowing by the specific implement can be predicted by the DEM model. The chisel plow is the most economic tool for increasing soil porosity. The moldboard is the best tool for soil manipulation. It can be concluded that the discrete element simulation can be used as a reliable engineering tool for soil-implement interaction quantitatively and qualitatively.
6
Swankie, Martin et Andrews. L51641 Evaluate NDT Methods for Welds in Service. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), mars 1990. http://dx.doi.org/10.55274/r0010626.
Texte intégralRésumé :
The inspection of welds made onto in-service pipelines, which are made primarily for attaching branch connections and repair sleeves, has been the subject of much concern in recent years. The difficulties associated with the inspection of these welds have long been recognized and, historically, the amount of inspection given to such welds has been small. The inspection of welds joining various appurtenances to pipelines is hampered for a number of reasons. The joint geometries can vary considerably, but none of them are particularly suited to detailed inspection. Surface techniques, such as magnetic particle and liquid-penetrant testing, rely on the flaws being at or near the surface, and this is not necessarily the case with the welds of concern. Radiography is difficult since it is not possible to place a radiation source within the pipeline. Ultrasonic inspection is, therefore, the only option if a full volumetric inspection is required. This is made difficult by the inherent complex geometries, and limited access to many of the welds. Welding on pipelines containing flowing, pressurized products results in very rapid cooling of the weld metal and heat-affected-zone regions, significantly increasing the risk of cracking. The use of high hydrogen consumables (specifically EXX10 SMAW electrodes) adds considerably to the risk The probability of discontinuities forming during welding on in-service pipelines is therefore considerably greater than for pipelines that do not contain flowing products. The goal of the present work was to evaluate existing techniques, and to develop and verify improved methodsfor inspection of such welds. In the first phase of this program, welded assemblies that contain realistic examples of discontinuities that occur in practice were produced In the second phase, the reliability of existing nondestructive testing methods were evaluated along with the reliability of novel nondestructive testing systems. The overall objectives of these first two phases were to evaluate the accuracy and reliability of nondestructive testing methods currently applied to welds made onto in-service pipelines, and to assess the improvement possible with methods that are more advanced, but so far have had limited application to these welds. The objective for the Phase III continuation of this project is to demonstrate the accuracy and reliability of nondestructive testing methods using procedures that are optimized based on the knowledge acquired in the first two phases.
7
Jung, Carina, Karl Indest, Matthew Carr, Richard Lance, Lyndsay Carrigee et Kayla Clark. Properties and detectability of rogue synthetic biology (SynBio) products in complex matrices. Engineer Research and Development Center (U.S.), septembre 2022. http://dx.doi.org/10.21079/11681/45345.
Texte intégralRésumé :
Synthetic biology (SynBio) aims to rationally engineer or modify traits of an organism or integrate the behaviors of multiple organisms into a singular functional organism through advanced genetic engineering techniques. One objective of this research was to determine the environmental persistence of engineered DNA in the environment. To accomplish this goal, the environmental persistence of legacy engineered DNA building blocks were targeted that laid the foundation for SynBio product development and application giving rise to “post-use products.” These building blocks include genetic constructs such as cloning and expression vectors, promoter/terminator elements, selectable markers, reporter genes, and multi-cloning sites. Shotgun sequencing of total DNA from water samples of pristine sites was performed and resultant sequence data mined for frequency of legacy recombinant DNA signatures. Another objective was to understand the fate of a standardized contemporary synthetic genetic construct (SC) in the context of various chassis systems/genetic configurations representing different degrees of “genetic bioavailability” to the environmental landscape. These studies were carried out using microcosms representing different environmental matrices (soils, waters, wastewater treatment plant (WWTP) liquor) and employed a novel genetic reporter system based on volatile organic compounds (VOC) detection to assess proliferation and persistence of the SC in the matrix over time.
8
Bray, Jonathan, Ross Boulanger, Misko Cubrinovski, Kohji Tokimatsu, Steven Kramer, Thomas O'Rourke, Ellen Rathje, Russell Green, Peter Robertson et Christine Beyzaei. U.S.—New Zealand— Japan International Workshop, Liquefaction-Induced Ground Movement Effects, University of California, Berkeley, California, 2-4 November 2016. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, mars 2017. http://dx.doi.org/10.55461/gzzx9906.
Texte intégralRésumé :
There is much to learn from the recent New Zealand and Japan earthquakes. These earthquakes produced differing levels of liquefaction-induced ground movements that damaged buildings, bridges, and buried utilities. Along with the often spectacular observations of infrastructure damage, there were many cases where well-built facilities located in areas of liquefaction-induced ground failure were not damaged. Researchers are working on characterizing and learning from these observations of both poor and good performance. The “Liquefaction-Induced Ground Movements Effects” workshop provided an opportunity to take advantage of recent research investments following these earthquake events to develop a path forward for an integrated understanding of how infrastructure performs with various levels of liquefaction. Fifty-five researchers in the field, two-thirds from the U.S. and one-third from New Zealand and Japan, convened in Berkeley, California, in November 2016. The objective of the workshop was to identify research thrusts offering the greatest potential for advancing our capabilities for understanding, evaluating, and mitigating the effects of liquefaction-induced ground movements on structures and lifelines. The workshop also advanced the development of younger researchers by identifying promising research opportunities and approaches, and promoting future collaborations among participants. During the workshop, participants identified five cross-cutting research priorities that need to be addressed to advance our scientific understanding of and engineering procedures for soil liquefaction effects during earthquakes. Accordingly, this report was organized to address five research themes: (1) case history data; (2) integrated site characterization; (3) numerical analysis; (4) challenging soils; and (5) effects and mitigation of liquefaction in the built environment and communities. These research themes provide an integrated approach toward transformative advances in addressing liquefaction hazards worldwide. The archival documentation of liquefaction case history datasets in electronic data repositories for use by the broader research community is critical to accelerating advances in liquefaction research. Many of the available liquefaction case history datasets are not fully documented, published, or shared. Developing and sharing well-documented liquefaction datasets reflect significant research efforts. Therefore, datasets should be published with a permanent DOI, with appropriate citation language for proper acknowledgment in publications that use the data. Integrated site characterization procedures that incorporate qualitative geologic information about the soil deposits at a site and the quantitative information from in situ and laboratory engineering tests of these soils are essential for quantifying and minimizing the uncertainties associated site characterization. Such information is vitally important to help identify potential failure modes and guide in situ testing. At the site scale, one potential way to do this is to use proxies for depositional environments. At the fabric and microstructure scale, the use of multiple in situ tests that induce different levels of strain should be used to characterize soil properties. The development of new in situ testing tools and methods that are more sensitive to soil fabric and microstructure should be continued. The development of robust, validated analytical procedures for evaluating the effects of liquefaction on civil infrastructure persists as a critical research topic. Robust validated analytical procedures would translate into more reliable evaluations of critical civil infrastructure iv performance, support the development of mechanics-based, practice-oriented engineering models, help eliminate suspected biases in our current engineering practices, and facilitate greater integration with structural, hydraulic, and wind engineering analysis capabilities for addressing multi-hazard problems. Effective collaboration across countries and disciplines is essential for developing analytical procedures that are robust across the full spectrum of geologic, infrastructure, and natural hazard loading conditions encountered in practice There are soils that are challenging to characterize, to model, and to evaluate, because their responses differ significantly from those of clean sands: they cannot be sampled and tested effectively using existing procedures, their properties cannot be estimated confidently using existing in situ testing methods, or constitutive models to describe their responses have not yet been developed or validated. Challenging soils include but are not limited to: interbedded soil deposits, intermediate (silty) soils, mine tailings, gravelly soils, crushable soils, aged soils, and cemented soils. New field and laboratory test procedures are required to characterize the responses of these materials to earthquake loadings, physical experiments are required to explore mechanisms, and new soil constitutive models tailored to describe the behavior of such soils are required. Well-documented case histories involving challenging soils where both the poor and good performance of engineered systems are documented are also of high priority. Characterizing and mitigating the effects of liquefaction on the built environment requires understanding its components and interactions as a system, including residential housing, commercial and industrial buildings, public buildings and facilities, and spatially distributed infrastructure, such as electric power, gas and liquid fuel, telecommunication, transportation, water supply, wastewater conveyance/treatment, and flood protection systems. Research to improve the characterization and mitigation of liquefaction effects on the built environment is essential for achieving resiliency. For example, the complex mechanisms of ground deformation caused by liquefaction and building response need to be clarified and the potential bias and dispersion in practice-oriented procedures for quantifying building response to liquefaction need to be quantified. Component-focused and system-performance research on lifeline response to liquefaction is required. Research on component behavior can be advanced by numerical simulations in combination with centrifuge and large-scale soil–structure interaction testing. System response requires advanced network analysis that accounts for the propagation of uncertainty in assessing the effects of liquefaction on large, geographically distributed systems. Lastly, research on liquefaction mitigation strategies, including aspects of ground improvement, structural modification, system health monitoring, and rapid recovery planning, is needed to identify the most effective, cost-efficient, and sustainable measures to improve the response and resiliency of the built environment.
9
Borch, Thomas, Yitzhak Hadar et Tamara Polubesova. Environmental fate of antiepileptic drugs and their metabolites : Biodegradation, complexation, and photodegradation. United States Department of Agriculture, janvier 2012. http://dx.doi.org/10.32747/2012.7597927.bard.
Texte intégralRésumé :
Many pharmaceutical compounds are active at very low doses, and a portion of them regularly enters municipal sewage systems and wastewater-treatment plants following use, where they often do not fully degrade. Two such compounds, CBZ and LTG, have been detected in wastewater effluents, surface waters, drinking water, and irrigation water, where they pose a risk to the environment and the food supply. These compounds are expected to interact with organic matter in the environment, but little is known about the effect of such interactions on their environmental fate and transport. The original objectives of our research, as defined in the approved proposal, were to: Determine the rates, mechanisms and products of photodegradation of LTG, CBZ and selected metabolites in waters exposed to near UV light, and the influence of DOM type and binding processes on photodegradation. Determine the potential and pathways for biodegradation of LTG, CBZ and selected metabolites using a white rot fungus (Pleurotusostreatus) and ADP, and reveal the effect of DOM complexation on these processes. Reveal the major mechanisms of binding of LTG, CBZ and selected metabolites to DOM and soil in the presence of DOM, and evaluate the effect of this binding on their photodegradation and/or biodegradation. We determined that LTG undergoes relatively slow photodegradation when exposed to UV light, and that pH affects each of LTG’s ability to absorb UV light, the efficiency of the resulting reaction, and the identities of LTG’sphotoproducts (t½ = 230 to 500 h during summer at latitude 40 °N). We observed that LTG’sphotodegradation is enhanced in the presence of DOM, and hypothesized that LTG undergoes direct reactions with DOM components through nucleophilic substitution reactions. In combination, these data suggest that LTG’s fate and transport in surface waters are controlled by environmental conditions that vary with time and location, potentially affecting the environment and irrigation waters. We determined that P. ostreatusgrows faster in a rich liquid medium (glucose peptone) than on a natural lignocellulosic substrate (cotton stalks) under SSF conditions, but that the overall CBZ removal rate was similar in both media. Different and more varied transformation products formed in the solid state culture, and we hypothesized that CBZ degradation would proceed further when P. ostreatusand the ᵉⁿᶻʸᵐᵃᵗⁱᶜ ᵖʳᵒᶠⁱˡᵉ ʷᵉʳᵉ ᵗᵘⁿᵉᵈ ᵗᵒ ˡⁱᵍⁿⁱⁿ ᵈᵉᵍʳᵃᵈᵃᵗⁱᵒⁿ. ᵂᵉ ᵒᵇˢᵉʳᵛᵉᵈ ¹⁴C⁻Cᴼ2 ʳᵉˡᵉᵃˢᵉ ʷʰᵉⁿ ¹⁴C⁻ᶜᵃʳᵇᵒⁿʸˡ⁻ labeled CBZ was used as the substrate in the solid state culture (17.4% of the initial radioactivity after 63 days of incubation), but could not conclude that mineralization had occurred. In comparison, we determined that LTG does not degrade in agricultural soils irrigated with treated wastewater, but that P. ostreatusremoves up to 70% of LTG in a glucose peptone medium. We detected various metabolites, including N-oxides and glycosides, but are still working to determine the degradation pathway. In combination, these data suggest that P. ostreatuscould be an innovative and effective tool for CBZ and LTG remediation in the environment and in wastewater used for irrigation. In batch experiments, we determined that the sorption of LTG, CBZ and selected metabolites to agricultural soils was governed mainly by SOM levels. In lysimeter experiments, we also observed LTG and CBZ accumulation in top soil layers enriched with organic matter. However, we detected CBZ and one of its metabolites in rain-fed wheat previously irrigated with treated wastewater, suggesting that their sorption was reversible, and indicating the potential for plant uptake and leaching. Finally, we used macroscale analyses (including adsorption/desorption trials and resin-based separations) with molecular- level characterization by FT-ICR MS to demonstrate the adsorptive fractionation of DOM from composted biosolids by mineral soil. This suggests that changes in soil and organic matter types will influence the extent of LTG and CBZ sorption to agricultural soils, as well as the potential for plant uptake and leaching.
10
Payment Systems Report - June of 2021. Banco de la República, février 2022. http://dx.doi.org/10.32468/rept-sist-pag.eng.2021.
Texte intégralRésumé :
Banco de la República provides a comprehensive overview of Colombia’s finan¬cial infrastructure in its Payment Systems Report, which is an important product of the work it does to oversee that infrastructure. The figures published in this edition of the report are for the year 2020, a pandemic period in which the con¬tainment measures designed and adopted to alleviate the strain on the health system led to a sharp reduction in economic activity and consumption in Colom¬bia, as was the case in most countries. At the start of the pandemic, the Board of Directors of Banco de la República adopted decisions that were necessary to supply the market with ample liquid¬ity in pesos and US dollars to guarantee market stability, protect the payment system and preserve the supply of credit. The pronounced growth in mone¬tary aggregates reflected an increased preference for liquidity, which Banco de la República addressed at the right time. These decisions were implemented through operations that were cleared and settled via the financial infrastructure. The second section of this report, following the introduction, offers an analysis of how the various financial infrastructures in Colombia have evolved and per¬formed. One of the highlights is the large-value payment system (CUD), which registered more momentum in 2020 than during the previous year, mainly be¬cause of an increase in average daily remunerated deposits made with Banco de la República by the General Directorate of Public Credit and the National Treasury (DGCPTN), as well as more activity in the sell/buy-back market with sovereign debt. Consequently, with more activity in the CUD, the Central Securi¬ties Depository (DCV) experienced an added impetus sparked by an increase in the money market for bonds and securities placed on the primary market by the national government. The value of operations cleared and settled through the Colombian Central Counterparty (CRCC) continues to grow, propelled largely by peso/dollar non-deliverable forward (NDF) contracts. With respect to the CRCC, it is important to note this clearing house has been in charge of managing risks and clearing and settling operations in the peso/dollar spot market since the end of last year, following its merger with the Foreign Exchange Clearing House of Colombia (CCDC). Since the final quarter of 2020, the CRCC has also been re¬sponsible for clearing and settlement in the equities market, which was former¬ly done by the Colombian Stock Exchange (BVC). The third section of this report provides an all-inclusive view of payments in the market for goods and services; namely, transactions carried out by members of the public and non-financial institutions. During the pandemic, inter- and intra-bank electronic funds transfers, which originate mostly with companies, increased in both the number and value of transactions with respect to 2019. However, debit and credit card payments, which are made largely by private citizens, declined compared to 2019. The incidence of payment by check contin¬ue to drop, exhibiting quite a pronounced downward trend during the past last year. To supplement to the information on electronic funds transfers, section three includes a segment (Box 4) characterizing the population with savings and checking accounts, based on data from a survey by Banco de la República con-cerning the perception of the use of payment instruments in 2019. There also is segment (Box 2) on the growth in transactions with a mobile wallet provided by a company specialized in electronic deposits and payments (Sedpe). It shows the number of users and the value of their transactions have increased since the wallet was introduced in late 2017, particularly during the pandemic. In addition, there is a diagnosis of the effects of the pandemic on the payment patterns of the population, based on data related to the use of cash in circu¬lation, payments with electronic instruments, and consumption and consumer confidence. The conclusion is that the collapse in the consumer confidence in¬dex and the drop in private consumption led to changes in the public’s pay¬ment patterns. Credit and debit card purchases were down, while payments for goods and services through electronic funds transfers increased. These findings, coupled with the considerable increase in cash in circulation, might indicate a possible precautionary cash hoarding by individuals and more use of cash as a payment instrument. There is also a segment (in Focus 3) on the major changes introduced in regulations on the retail-value payment system in Colombia, as provided for in Decree 1692 of December 2020. The fourth section of this report refers to the important innovations and tech¬nological changes that have occurred in the retail-value payment system. Four themes are highlighted in this respect. The first is a key point in building the financial infrastructure for instant payments. It involves of the design and im¬plementation of overlay schemes, a technological development that allows the various participants in the payment chain to communicate openly. The result is a high degree of interoperability among the different payment service providers. The second topic explores developments in the international debate on central bank digital currency (CBDC). The purpose is to understand how it could impact the retail-value payment system and the use of cash if it were to be issued. The third topic is related to new forms of payment initiation, such as QR codes, bio¬metrics or near field communication (NFC) technology. These seemingly small changes can have a major impact on the user’s experience with the retail-value payment system. The fourth theme is the growth in payments via mobile tele¬phone and the internet. The report ends in section five with a review of two papers on applied research done at Banco de la República in 2020. The first analyzes the extent of the CRCC’s capital, acknowledging the relevant role this infrastructure has acquired in pro¬viding clearing and settlement services for various financial markets in Colom¬bia. The capital requirements defined for central counterparties in some jurisdic¬tions are explored, and the risks to be hedged are identified from the standpoint of the service these type of institutions offer to the market and those associated with their corporate activity. The CRCC’s capital levels are analyzed in light of what has been observed in the European Union’s regulations, and the conclusion is that the CRCC has a scheme of security rings very similar to those applied internationally and the extent of its capital exceeds what is stipulated in Colombian regulations, being sufficient to hedge other risks. The second study presents an algorithm used to identify and quantify the liquidity sources that CUD’s participants use under normal conditions to meet their daily obligations in the local financial market. This algorithm can be used as a tool to monitor intraday liquidity. Leonardo Villar Gómez Governor