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Статті в журналах з теми "Direct surface interactions":
1
Peyre, P., M. Gharbi, C. Gorny, M. Carin, S. Morville, Denis Carron, P. Le Masson, T. Malot, and R. Fabbro. "Surface Finish Issues after Direct Metal Deposition." Materials Science Forum 706-709 (January 2012): 228–33. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.228.
Анотація:
Derived from laser cladding, the Direct Metal Deposition (DMD) laser process, is based upon a laser beam – projected powder interaction, and allows manufacturing complex 3D shapes much faster than conventional processes. However, the surface finish remains critical, and DMD parts usually necessitate post-machining steps. In this context, the focus of our work was: (1) to understand the physical mechanisms responsible for deleterious surface finishes, (2) to propose different experimental solutions for improving surface finish. Our experimental approach is based upon: (1) adequate modifications of the DMD conditions (gas shielding, laser conditions, coaxial or off-axis nozzles), (2) a characterization of laser-powder-melt-pool interactions using fast camera analysis, (3) a precise check of surface aspects using 3D profilometry, SEM, (4) preliminary thermo-convective simulations to understand melt-pool hydrodynamics. Most of the experimental tests were carried out on a Ti6Al4V titanium alloy, widely investigated already. Results confirm that surface degradation depends on two aspects: the sticking of non-melted or partially melted particles on the free surfaces, and the formation of menisci with more or less pronounced curvature radii. Among other aspects, a reduction of layer thickness and an increase of melt-pool volumes to favor re-melting processes are shown to have a beneficial effect on roughness parameters.
2
Linne, Christine, Daniele Visco, Stefano Angioletti-Uberti, Liedewij Laan, and Daniela J. Kraft. "Direct visualization of superselective colloid-surface binding mediated by multivalent interactions." Proceedings of the National Academy of Sciences 118, no. 36 (August 31, 2021): e2106036118. http://dx.doi.org/10.1073/pnas.2106036118.
Анотація:
Reliably distinguishing between cells based on minute differences in receptor density is crucial for cell–cell or virus–cell recognition, the initiation of signal transduction, and selective targeting in directed drug delivery. Such sharp differentiation between different surfaces based on their receptor density can only be achieved by multivalent interactions. Several theoretical and experimental works have contributed to our understanding of this “superselectivity.” However, a versatile, controlled experimental model system that allows quantitative measurements on the ligand–receptor level is still missing. Here, we present a multivalent model system based on colloidal particles equipped with surface-mobile DNA linkers that can superselectively target a surface functionalized with the complementary mobile DNA-linkers. Using a combined approach of light microscopy and Foerster resonance energy transfer (FRET), we can directly observe the binding and recruitment of the ligand–receptor pairs in the contact area. We find a nonlinear transition in colloid-surface binding probability with increasing ligand or receptor concentration. In addition, we observe an increased sensitivity with weaker ligand–receptor interactions, and we confirm that the timescale of binding reversibility of individual linkers has a strong influence on superselectivity. These unprecedented insights on the ligand–receptor level provide dynamic information into the multivalent interaction between two fluidic membranes mediated by both mobile receptors and ligands and will enable future work on the role of spatial–temporal ligand–receptor dynamics on colloid-surface binding.
3
Lai, Chiu-Chun, Kuo-Shien Huang, Po-Wei Su, Chang-Mou Wu, and Ching-Nan Huang. "Interactions of modified Gemini surfactants: Interactions with direct dyes and dyeing properties in cotton fabrics." Modern Physics Letters B 33, no. 14n15 (May 28, 2019): 1940002. http://dx.doi.org/10.1142/s0217984919400025.
Анотація:
This study investigated dye–surfactant interactions between a series of modified Gemini surfactants and commercial direct dyes in aqueous solution and their corresponding effects on cotton fabric dyeing. A surface tension meter was also used to measure surface activities of compounds containing electrolyte under conditions similar to those in dyeing processes. The surface tension measurements showed lower than normal surface tension in surfactant solutions containing electrolyte. From the UV-Vis spectra, the isosbestic point indicated that dye–surfactant complexes had formed and existed as hydrophilic interaction between direct dyes and modified Gemini surfactants. When dyeing cotton fabric with red dye and orange dye, the presence of these surfactants decreased dye uptake rate but increased for blue dye because the dye–surfactant interaction had formed a hydrophilic complex.
4
Norris, Anne, Mario A. Bianchet, and Jef D. Boeke. "Compensatory Interactions between Sir3p and the Nucleosomal LRS Surface Imply Their Direct Interaction." PLoS Genetics 4, no. 12 (December 12, 2008): e1000301. http://dx.doi.org/10.1371/journal.pgen.1000301.
5
Zhu, Chongqin, Yurui Gao, Weiduo Zhu, Jian Jiang, Jie Liu, Jianjun Wang, Joseph S. Francisco, and Xiao Cheng Zeng. "Direct observation of 2-dimensional ices on different surfaces near room temperature without confinement." Proceedings of the National Academy of Sciences 116, no. 34 (August 2, 2019): 16723–28. http://dx.doi.org/10.1073/pnas.1905917116.
Анотація:
Water–solid interfaces play important roles in a wide range of fields, including atmospheric science, geochemistry, electrochemistry, and food science. Herein, we report simulation evidence of 2-dimensional (2D) ice formation on various surfaces and the dependence of the 2D crystalline structure on the hydrophobicity and morphology of the underlying surface. Contrary to the prevailing view that nanoscale confinement is necessary for the 2D liquid-to-bilayer ice transition, we find that the liquid-to-bilayer hexagonal ice (BHI) transition can occur either on a model smooth surface or on model fcc-crystal surfaces with indices of (100), (110), and (111) near room temperature. We identify a critical parameter that characterizes the water–surface interaction, above which the BHI can form on the surface. This critical parameter increases as the temperature increases. Even at temperatures above the freezing temperature of bulk ice (Ih), we find that BHI can also form on a superhydrophilic surface due to the strong water–surface interaction. The tendency toward the formation of BHI without confinement reflects a proper water–surface interaction that can compensate for the entropy loss during the freezing transition. Furthermore, phase diagrams of 2D ice formation are described on the plane of the adsorption energy versus the fcc lattice constant (Eads–afcc), where 4 monolayer square-like ices are also identified on the fcc model surfaces with distinct water–surface interactions.
6
Touhami, Ahmed, Barbara Hoffmann, Andrea Vasella, Frédéric A. Denis, and Yves F. Dufrêne. "Aggregation of yeast cells: direct measurement of discrete lectin–carbohydrate interactions." Microbiology 149, no. 10 (October 1, 2003): 2873–78. http://dx.doi.org/10.1099/mic.0.26431-0.
Анотація:
Aggregation of microbial cells mediated by specific interactions plays a pivotal role in the natural environment, in medicine and in biotechnological processes. Here we used atomic force microscopy (AFM) to measure individual lectin–carbohydrate interactions involved in the flocculation of yeast cells, an aggregation event of crucial importance in fermentation technology. AFM probes functionalized with oligoglucose carbohydrates were used to record force-distance curves on living yeast cells at a rate of 0·5 μm s−1. Flocculating cells showed adhesion forces of 121±53 pN, reflecting the specific interaction between individual cell-surface lectins and glucose residues. Similar adhesion forces, 117±41 pN, were measured using probes functionalized with the lectin concanavalin A and attributed to specific binding to cell-surface mannose residues. By contrast, specific interaction forces were not observed in non-flocculating conditions, i.e. in the presence of mannose or when using non-flocculating cells, pointing to their involvement in yeast flocculation. The single molecule force spectroscopy measurements presented here provide a means to study a variety of cellular interactions at the molecular level, such as the adhesion of bacteria to animal and plant tissues.
7
Hendrix, Martin, E. Scott Priestley, Gerald F. Joyce, and Chi-Huey Wong. "Direct Observation of Aminoglycoside−RNA Interactions by Surface Plasmon Resonance." Journal of the American Chemical Society 119, no. 16 (April 1997): 3641–48. http://dx.doi.org/10.1021/ja964290o.
8
Singla, Saranshu, Dharamdeep Jain, Chelsea M. Zoltowski, Sriharsha Voleti, Alyssa Y. Stark, Peter H. Niewiarowski, and Ali Dhinojwala. "Direct evidence of acid-base interactions in gecko adhesion." Science Advances 7, no. 21 (May 2021): eabd9410. http://dx.doi.org/10.1126/sciadv.abd9410.
Анотація:
While it is generally accepted that van der Waals (vdW) forces govern gecko adhesion, several studies indicate contributions from non-vdW forces and highlight the importance of understanding the adhesive contact interface. Previous work hypothesized that the surface of gecko setae is hydrophobic, with nonpolar lipid tails exposed on the surface. However, direct experimental evidence supporting this hypothesis and its implications on the adhesion mechanism is lacking. Here, we investigate the sapphire-setae contact interface using interface-sensitive spectroscopy and provide direct evidence of the involvement of acid-base interactions between polar lipid headgroups exposed on the setal surface and sapphire. During detachment, a layer of unbound lipids is left as a footprint due to cohesive failure within the lipid layer, which, in turn, reduces wear to setae during high stress sliding. The absence of this lipid layer enhances adhesion, despite a small setal-substrate contact area. Our results show that gecko adhesion is not exclusively a vdW-based, residue-free system.
9
Ivanov, A. S., and A. E. Medvedev. "Optical surface plasmon resonance biosensors in molecular fishing." Biomeditsinskaya Khimiya 61, no. 2 (2015): 231–38. http://dx.doi.org/10.18097/pbmc20156102231.
Анотація:
An optical biosensor employing surface plasmon resonance is a highly efficient instrument applicable for direct real time registration of molecular interactions without additional use of any labels or coupled processes. As an independent approach it is especially effective in analysis of various ligand receptor interactions. SPR-biosensors are used for validation of studies on intermolecular interactions in complex biological systems (affinity profiling of various groups of proteins, etc.). Recently, potential application of the SPR-biosensor for molecular fishing (direct affinity binding of target molecules from complex biological mixtures on the optical biosensor surface followed by their elution for identification by LC-MS/MS) has been demonstrated. Using SPR-biosensors in such studies it is possible to solve the following tasks: (a) SPR-based selection of immobilization conditions required for the most effective affinity separation of a particular biological sample; (b) SPR-based molecular fishing for subsequent protein identification by mass spectrometry; (c) SPR-based validation of the interaction of identified proteins with immobilized ligand. This review considers practical application of the SPR technology in the context of recent studies performed in the Institute of Biomedical Chemistry on molecular fishing of real biological objects.
10
Yang, Hui, Wei Zhang, Ting Chen, Shizhe Huang, Baogang Quan, Min Wang, Junjie Li, Changzhi Gu, and Jinben Wang. "Direct Experimental Evidence of Biomimetic Surfaces with Chemical Modifications Interfering with Adhesive Protein Adsorption." Molecules 24, no. 1 (December 21, 2018): 27. http://dx.doi.org/10.3390/molecules24010027.
Анотація:
Current approaches to dealing with the worldwide problem of marine biofouling are to impart chemical functionality to the surface or utilize microtopography inspired by nature. Previous reports have shown that only introducing a single method may not resist adhesion of mussels or inhibit biofouling in static forms. While it is promising to integrate two methods to develop an effective antifouling strategy, related basic research is still lacking. Here, we have fabricated engineered shark skin surfaces with different feature heights and terminated with different chemical moieties. Atomic force microscopy (AFM) with a modified colloid probe technique and quartz crystal microbalance with a dissipation n (QCM-D) monitoring method have been introduced to directly determine the interactions between adhesive proteins and functionalized surfaces. Our results indicate that the adhesion strength of probe-surface decreases with increasing feature height, and it also decreases from bare Si surface to alkyl and hydroxyl modification, which is attributed to different contact area domains and interaction mechanisms. Combining biomimetic microtopography and surface chemistry, our study provides a new perspective for designing and developing underwater anti-fouling materials.
Дисертації з теми "Direct surface interactions":
1
Wu, Hung-Jen. "Direct measurements of ensemble particle and surface interactions on homogeneous and patterned substrates." Texas A&M University, 2005. http://hdl.handle.net/1969.1/3747.
Анотація:
In this dissertation, we describe a novel method that we call Diffusing Colloidal
Probe Microscopy (DCPM), which integrates Total Internal Reflection Microscopy
(TIRM) and Video Microscopy (VM) methods to monitor three dimensional trajectories
in colloidal ensembles levitated above macroscopic surfaces. TIRM and VM are well
established optical microscopy techniques for measuring normal and lateral colloidal
excursions near macroscopic planar surfaces. The interactions between particle-particle
and particle-substrate in colloidal interfacial systems are interpreted by statistical
analyses from distributions of colloidal particles; dynamic properties of colloidal
assembly are also determined from particle trajectories.
Our studies show that DCPM is able to detect many particle-surface interactions
simultaneously and provides an ensemble average measurement of particle-surface
interactions on a homogeneous surface to allow direct comparison of distributed and
average properties. A benefit of ensemble averaging of many particles is the diminished
need for time averaging, which can produce orders of magnitude faster measurement
times at higher interfacial particle concentrations. The statistical analyses (Ornstein-
Zernike and three dimensional Monte Carlo analyses) are used to obtain particle-particle
interactions from lateral distribution functions and to understand the role of nonuniformities
in interfacial colloidal systems. An inconsistent finding is the observation of
an anomalous long range particle-particle attraction and recovery of the expected DLVO
particle-wall interactions for all concentrations examined. The possible influence of
charge heterogeneity and particle size polydispersity on measured distribution functions
is discussed in regard to inconsistent particle-wall and particle-particle potentials. In the final part of this research, the ability of DCPM is demonstrated to map potential energy
landscapes on patterned surfaces by monitoring interactions between diffusing colloidal
probes with Au pattern features. Absolute separation is obtained from theoretical fits to
measured potential energy profiles and direct measurement by sticking silica colloids to
Au surfaces via electrophoretic deposition. Initial results indicate that, as colloidal probe
and pattern feature dimensions become comparable, measured potential energy profiles
suffer some distortion due to the increased probability of probes interacting with
surfaces at the edges of adjacent pattern features. Measurements of lateral diffusion via
analysis of mean square displacements also indicated lateral diffusion coefficients in
excellent agreement with rigorous theoretical predictions.
2
Awassa, Jazia. "Mécanismes antibactériens des hydroxydes doubles lamellaires à base de zinc." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0155.
Анотація:
Les hydroxydes doubles lamellaires (HDL) sont des composés solides constitués par un ensemble de feuilles d'hydroxydes métalliques divalents M(II) et trivalents M(III) entre lesquels s’insèrent des anions et des molécules d’eau. En raison de la flexibilité des HDL en termes de propriétés physico-chimiques, l’étude des différents mécanismes antibactériens qui leurs sont associés présente un intérêt croissant. Ce travail de thèse vise à étudier différentes hypothèses proposées pour explique l'effet antibactérien des hydroxydes doubles lamellaire (HDL) à base de zinc : (1) interactions directes entre la surface des HDL et les parois bactériennes, (2) libération d'ions métalliques divalents en solution depuis les feuillets des HDL, (3) génération d'espèces réactives de l'oxygène (ROS). Lors d’une première étude, une investigation globale a été réalisée pour déterminer les différents paramètres physico-chimiques influençant l'activité antibactérienne des HDLs M(II)Al(III) (M= Zn, Cu, Ni, Co, Mg). L'effet antimicrobien des HDLs contre les bactéries Gram-positives Staphylococcus aureus et Gram-négatives Escherichia coli a été corrélé en premier lieu à la nature du métal divalent, et en second lieu à la quantité d'ions M2+aq libérés dans le milieu de culture. Cet effet était plus prononcé pour les HDLs à base de Zn(II) possédant la plus forte activité antibactérienne et dont les propriétés antibactériennes dépendent du profil de libération des ions Zn2+aq (Mécanisme 2) contrôlée initialement par les différents paramètres physico-chimiques étudiés. De plus, rôle du contact direct (Mécanisme 2) a été validé pour les HDLs à base de Zn(II) en comparant l'activité antibactérienne d’HDLs de taille micrométrique contre S. aureus à celle des nanoparticules (NPs) d’HDL présentant un effet antibactérien supérieur. La présence d'interactions spécifiques entre les HDLs à base de Zn(II) et la paroi de S. aureus a été validée par microscopie à force atomique en mode spectroscopie de force (AFM-FS). L'amélioration des propriétés antibactériennes des NPs d’HDL à base de Zn(II) par la génération de ROS (Mécanisme 3) en présence de lumière UVA a également été évaluée. Après avoir fourni des preuves expérimentales sur les trois mécanismes suggérés, la contribution de chaque mécanisme dans l'activité antibactérienne des HDLs à base de Zn(II) a été déterminéLayered double hydroxides (LDH) are solid compounds constituted by the stacking of divalent M(II) and trivalent M(III) metal hydroxide sheets separated by an interlayer of anions and water molecules. Due to the versatility of LDH in terms of their tunable physico-chemical properties, a growing interest arises for investigating their different antibacterial activity mechanisms. This thesis work aims at studying the different proposed hypotheses explaining the antibacterial effect of pristine zinc-based LDHs: (1) direct interactions between the surface of LDH and bacterial cell walls, (2) release of constituent divalent metal ions, (3) generation of reactive oxygen species (ROS). First a global investigation was performed to determine the different physico-chemical parameters influencing the antibacterial activity of pristine M(II)Al(III) LDHs (M= Zn, Cu, Ni, Co, Mg). The antimicrobial effect of LDHs against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria was linked in the first place to the nature of divalent metal itself, and to the amount of released M2+aq ions into the culture media in the second place. This effect was more easily identified in Zn(II)-based LDHs possessing the strongest antibacterial activity and whose antibacterial properties depended on their release profile of Zn2+aq ions (Mechanism 2) initially controlled by the different physico-chemical parameters. Moreover, the direct contact mechanism (Mechanism 1) was validated for Zn(II)-based LDHs by comparing the antibacterial activity of micron-sized LDHs against S. aureus to that of LDH nanoparticles (NPs) exhibiting a greater antibacterial effect. The presence of specific surface interactions between Zn(II)-based LDHs and the cell wall of S. aureus was further validated by atomic force microscopy-based force spectroscopy (AFM-FS). The enhancement of the antibacterial properties of Zn(II)-based LDH NPs by ROS generation (Mechanism 3) in presence of UVA light was also assessed. After providing experimental evidences about the three suggested mechanisms, the role of each mechanism contributing to the antibacterial activity of Zn(II)-based LDHs in different antibacterial tests assays was determined
3
Took, Roger Kenton. "Surface interaction : separating direct manipulation interfaces from their applications." Thesis, University of York, 1990. http://etheses.whiterose.ac.uk/13997/.
Анотація:
To promote both quality and economy in the production of applications and their interactive interfaces, it is desirable to delay their mutual binding. The later the binding, the more separable the interface from its application. An ideally separated interface can factor tasks from a range of applications, can provide a level of independence from hardware I/O devices, and can be responsive to end-user requirements. Current interface systems base their separation on two different abstractions. In linguistic architectures, for example User Interface Management Systems in the Seeheim model, the dialogue or syntax of interaction is abstracted in a separate notation. In agent architectures like Toolkits, interactive devices, at various levels of complexity, are abstracted into a class or call hierarchy. This Thesis identifies an essential feature of the popular notion of direct manipulation: directness requires that the same object be used both for output and input. In practice this compromises the separation of both dialogue and devices. In addition, dialogue cannot usefully be abstracted from its application functionality, while device abstraction reduces the designer's expressive control by binding presentation style to application semantics. This Thesis proposes an alternative separation, based on the abstraction of the medium of interaction, together with a dedicated user agent which allows direct manipulation of the medium. This interactive medium is called the surface. The Thesis proposes two new models for the surface, the first of which has been implemented as Presenter, the second of which is an ideal design permitting document quality interfaces. The major contribution of the Thesis is a precise specification of an architecture (UMA), whereby a separated surface can preserve directness without binding in application semantics, and at the same time an application can express its semantics on the surface without needing to manage all the details of interaction. Thus UMA partitions interaction into Surface Interaction, and deep interaction. Surface Interaction factors a large portion of the task of maintaining a highly manipulable interface, and brings the roles of user and application designer closer.
4
Musehane, Ndivhuwo M. "Direct numerical simulation of bubble-bubble and droplet-droplet interaction using a Surface Thin Film model." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/22963.
Анотація:
This dissertation deals with the simulation of dispersed multiphase flow. The particle-particle and particle-fluid interactions in this class of flows play an important role on the hydrodynamics and fluid transport phenomena that govern the overall flow behaviour. Accurate computational modelling of the particle-particle and particle- fluid interactions is thus required to correctly model the flow. The aim of this study is to use a Direct Numerical Simulation approach based on a smoothed Volume Of Fluid method to model particle-particle interactions in a dispersed multiphase flow at a fundamental level, and employing a surface thin film model, to drastically reduce the computational effort required. A multiscale modelling approach is followed with the smoothed Volume Of Fluid simulation on the particle scale and the surface thin film model simulation on the thin- film scale. The resulting governing equations are the Navier-Stokes equations for an incompressible viscous multiphase Newtonian fluid undergoing laminar and isothermal three-dimensional flow, the interface advection equation and the reduced order surface thin film equation. The model equations are discretized using the Finite Volume Method and implemented into the open source software OpenFOAM®. The numerical solution is obtained by solving the resulting non-linear system of equations implicitly on a structured computational grid on parallel processors using a pressure correction algorithm to converge the pressure at each time step. The study is restricted to gas-liquid systems where particles could either be bubbles or droplets; rigid particles are not considered. The model is tested against experimental results from binary collision of hydrocarbon droplets. Good qualitative numerical results are obtained at a practical computational cost.
5
Everett, William Neil. "Evanescent wave and video microscopy methods for directly measuring interactions between surface-immobilized biomolecules." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1585.
6
Bratuta, E. G., R. G. Akmen, T. I. Jaroshenko, and O. V. Krugliakova. "The influence of interaction surface structure and irrigation scheme on heat and mass transfer in direct contact condenser." Thesis, Országos Sugárbiológiai és Sugáregészségügyi Kutató Intézet (OSSKI), 1997. http://repository.kpi.kharkov.ua/handle/KhPI-Press/23120.
Анотація:
The contact condensation of saturated steam on liquid spray has been studied. The mathematical model of heat and mass transfer processes between dispersed liquid and steam has been usin one-parameter drop distribution function has been worked out. The rational degree of liquid dispersing and optimál irrigation scheme has been defined.
7
Jespersen, Michael L. 1979. "Engineering the macro-nano interface: Designing the directed self-assembly and interfacial interactions of gold nanoparticle monolayers." Thesis, University of Oregon, 2008. http://hdl.handle.net/1794/7504.
Анотація:
xviii, 192 p.Gold nanoparticles in the 1-2 mn core diameter size regime have generated a great deal of interest due to their size-dependent electronic, optical, and catalytic properties. A number of proof-of-concept experiments have demonstrated that small metal nanoparticles can be integrated into single electron transistors and optical waveguides. Still, reliable incorporation of gold nanoparticles into devices requires practical methods for their assembly on surfaces. Additionally, surface modification methods must be developed in order to control interparticle interactions and nanoparticle-environment interactions for use in sensing and catalysis. In this research, nanoparticle-substrate interactions were utilized to assemble surface-bound gold nanoparticle monolayers with interesting electronic and catalytic properties. Gold nanoparticles (1.5 nm diameter) with a thiol ligand shell containing phosphonic acid terminal functionality were synthesized and assembled selectively onto hafnium-modified silicon dioxide substrates through bonding of the terminal phosphonate to Hf(IV) surface groups. By increasing the surface coverage of Hf, it was possible to assemble monolayers of gold nanoparticles dense enough to exhibit nonlinear current-voltage properties across a 5-μm electrode gap at room temperature. Moreover, by taking advantage of the selectivity of this ligand shell for ZnO over SiO 2 , small gold nanoparticles were utilized as catalysts for selective growth of patterned, vertical ZnO nanowire arrays. In addition to engineering nanoparticle-substrate interactions, new surface modification methods were introduced to manipulate the interaction of the as-deposited gold nanoparticle monolayers with the environment. For example, thiol-thiol ligand exchange reactions were carried out on the surface-bound nanoparticle monolayers by immersion in dilute thiol solutions. Contact angle and XPS measurements indicate that the upper, surface-exposed phosphonic acid ligands are replaced by incoming thiol ligands. TEM measurements indicate that nanoparticle monolayers remain surface-bound and are stable to this exchange process, as the average particle size and surface coverage are preserved. As another example, the ligand shell can be partially removed by UV/ozone treatment to expose bare gold cores to the surrounding environment. On metal oxide substrates, this approach activates the particles for room temperature oxidation of carbon monoxide to carbon dioxide. This dissertation includes both my previously published and my co-authored materials.
Adviser: James E. Hutchison
8
Zhang, Jing. "Design and implementation of DNA-Directed Immobilisation (DDI) glycoarrays for probing carbohydrate-protein interactions." Phd thesis, Ecole Centrale de Lyon, 2010. http://tel.archives-ouvertes.fr/tel-00605541.
9
Rümelin, Sonja [Verfasser], and Andreas [Akademischer Betreuer] Butz. "The cockpit for the 21st century : exploring large and shaped interactive surfaces for direct interaction / Sonja Rümelin. Betreuer: Andreas Butz." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2014. http://d-nb.info/1059069768/34.
10
Rümelin, Sonja Verfasser], and Andreas [Akademischer Betreuer] [Butz. "The cockpit for the 21st century : exploring large and shaped interactive surfaces for direct interaction / Sonja Rümelin. Betreuer: Andreas Butz." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-174280.
Книги з теми "Direct surface interactions":
1
Kirchman, David L. Introduction to geomicrobiology. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198789406.003.0013.
Анотація:
Geomicrobiology, the marriage of geology and microbiology, is about the impact of microbes on Earth materials in terrestrial systems and sediments. Many geomicrobiological processes occur over long timescales. Even the slow growth and low activity of microbes, however, have big effects when added up over millennia. After reviewing the basics of bacteria–surface interactions, the chapter moves on to discussing biomineralization, which is the microbially mediated formation of solid minerals from soluble ions. The role of microbes can vary from merely providing passive surfaces for mineral formation, to active control of the entire precipitation process. The formation of carbonate-containing minerals by coccolithophorids and other marine organisms is especially important because of the role of these minerals in the carbon cycle. Iron minerals can be formed by chemolithoautotrophic bacteria, which gain a small amount of energy from iron oxidation. Similarly, manganese-rich minerals are formed during manganese oxidation, although how this reaction benefits microbes is unclear. These minerals and others give geologists and geomicrobiologists clues about early life on Earth. In addition to forming minerals, microbes help to dissolve them, a process called weathering. Microbes contribute to weathering and mineral dissolution through several mechanisms: production of protons (acidity) or hydroxides that dissolve minerals; production of ligands that chelate metals in minerals thereby breaking up the solid phase; and direct reduction of mineral-bound metals to more soluble forms. The chapter ends with some comments about the role of microbes in degrading oil and other fossil fuels.
2
Dolman, A. Johannes, Luis U. Vilasa-Abad, and Thomas A. J. Janssen. Ecohydrological Concepts of Water-Vegetation Interaction in the Drylands of Africa. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.554.
Анотація:
Drylands cover around 40% of the land surface on Earth and are inhabited by more than 2 billion people, who are directly dependent on these lands. Drylands are characterized by a highly variable rainfall regime and inherent vegetation-climate feedbacks that can enhance the resilience of the system, but also can amplify disturbances. In that way, the system may get locked into two alternate stable states: one relatively wet and vegetated, and the other dry and barren. The resilience of dryland ecosystems derives from a number of adaptive mechanisms by which the vegetation copes with prolonged water stress, such as hydraulic redistribution. The stochastic nature of both the vegetation dynamics and the rainfall regime is a key characteristic of these systems and affects its management in relation to the feedbacks. How the ecohydrology of the African drylands will change in the future depends on further changes in climate, human disturbances, land use, and the socioeconomic system.
3
Horing, Norman J. Morgenstern. Retarded Green’s Functions. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198791942.003.0005.
Анотація:
Chapter 5 introduces single-particle retarded Green’s functions, which provide the probability amplitude that a particle created at (x, t) is later annihilated at (x′,t′). Partial Green’s functions, which represent the time development of one (or a few) state(s) that may be understood as localized but are in interaction with a continuum of states, are discussed and applied to chemisorption. Introductions are also made to the Dyson integral equation, T-matrix and the Dirac delta-function potential, with the latter applied to random impurity scattering. The retarded Green’s function in the presence of random impurity scattering is exhibited in the Born and self-consistent Born approximations, with application to Ando’s semi-elliptic density of states for the 2D Landau-quantized electron-impurity system. Important retarded Green’s functions and their methods of derivation are discussed. These include Green’s functions for electrons in magnetic fields in both three dimensions and two dimensions, also a Hamilton equation-of-motion method for the determination of Green’s functions with application to a 2D saddle potential in a time-dependent electric field. Moreover, separable Hamiltonians and their product Green’s functions are discussed with application to a one-dimensional superlattice in axial electric and magnetic fields. Green’s function matching/joining techniques are introduced and applied to spatially varying mass (heterostructures) and non-local electrostatics (surface plasmons).
4
Zydroń, Tymoteusz. Wpływ systemów korzeniowych wybranych gatunków drzew na przyrost wytrzymałości gruntu na ścinanie. Publishing House of the University of Agriculture in Krakow, 2019. http://dx.doi.org/10.15576/978-83-66602-46-5.
Анотація:
The aim of the paper was to determine the influence of root systems of chosen tree species found in the Polish Flysch Carpathians on the increase of soil shear strength (root cohesion) in terms of slope stability. The paper's goal was achieved through comprehensive tests on root systems of eight relatively common in the Polish Flysch Carpathians tree species. The tests that were carried out included field work, laboratory work and analytical calculations. As part of the field work, the root area ratio (A IA) of the roots was determined using the method of profiling the walls of the trench at a distance of about 1.0 m from the tree trunk. The width of the. trenches was about 1.0 m, and their depth depended on the ground conditions and ranged from 0.6 to 1.0 m below the ground level. After preparing the walls of the trench, the profile was divided into vertical layers with a height of 0.1 m, within which root diameters were measured. Roots with diameters from 1 to 10 mm were taken into consideration in root area ratio calculations in accordance with the generally accepted methodology for this type of tests. These measurements were made in Biegnik (silver fir), Ropica Polska (silver birch, black locust) and Szymbark (silver birch, European beech, European hornbeam, silver fir, sycamore maple, Scots pine, European spruce) located near Gorlice (The Low Beskids) in areas with unplanned forest management. In case of each tested tree species the samples of roots were taken, transported to the laboratory and then saturated with water for at least one day. Before testing the samples were obtained from the water and stretched in a. tensile testing machine in order to determine their tensile strength and flexibility. In general, over 2200 root samples were tested. The results of tests on root area ratio of root systems and their tensile strength were used to determine the value of increase in shear strength of the soils, called root cohesion. To this purpose a classic Wu-Waldron calculation model was used as well as two types of bundle models, the so called static model (Fiber Bundle Model — FIRM, FBM2, FBM3) and the deformation model (Root Bundle Model— RBM1, RBM2, mRBM1) that differ in terms of the assumptions concerning the way the tensile force is distributed to the roots as well as the range of parameters taken into account during calculations. The stability analysis of 8 landslides in forest areas of Cicikowicleie and Wignickie Foothills was a form of verification of relevance of the obtained calculation results. The results of tests on root area ratio in the profile showed that, as expected, the number of roots in the soil profile and their ApIA values are very variable. It was shown that the values of the root area ratio of the tested tree species with a diameter 1-10 ram are a maximum of 0.8% close to the surface of the ground and they decrease along with the depth reaching the values at least one order of magnitude lower than close to the surface at the depth 0.5-1.0 m below the ground level. Average values of the root area ratio within the soil profile were from 0.05 to 0.13% adequately for Scots pine and European beech. The measured values of the root area ratio are relatively low in relation to the values of this parameter given in literature, which is probably connected with great cohesiveness of the soils and the fact that there were a lot of rock fragments in the soil, where the tests were carried out. Calculation results of the Gale-Grigal function indicate that a distribution of roots in the soil profile is similar for the tested species, apart from the silver fir from Bie§nik and European hornbeam. Considering the number of roots, their distribution in the soil profile and the root area ratio it appears that — considering slope stability — the root systems of European beech and black locust are the most optimal, which coincides with tests results given in literature. The results of tensile strength tests showed that the roots of the tested tree species have different tensile strength. The roots of European beech and European hornbeam had high tensile strength, whereas the roots of conifers and silver birch in deciduous trees — low. The analysis of test results also showed that the roots of the studied tree species are characterized by high variability of mechanical properties. The values Of shear strength increase are mainly related to the number and size (diameter) of the roots in the soil profile as well as their tensile strength and pullout resistance, although they can also result from the used calculation method (calculation model). The tests showed that the distribution of roots in the soil and their tensile strength are characterized by large variability, which allows the conclusion that using typical geotechnical calculations, which take into consideration the role of root systems is exposed to a high risk of overestimating their influence on the soil reinforcement. hence, while determining or assuming the increase in shear strength of soil reinforced with roots (root cohesion) for design calculations, a conservative (careful) approach that includes the most unfavourable values of this parameter should be used. Tests showed that the values of shear strength increase of the soil reinforced with roots calculated using Wu-Waldron model in extreme cases are three times higher than the values calculated using bundle models. In general, the most conservative calculation results of the shear strength increase were obtained using deformation bundle models: RBM2 (RBMw) or mRBM1. RBM2 model considers the variability of strength characteristics of soils described by Weibull survival function and in most cases gives the lowest values of the shear strength increase, which usually constitute 50% of the values of shear strength increase determined using classic Wu-Waldron model. Whereas the second model (mRBM1.) considers averaged values of roots strength parameters as well as the possibility that two main mechanism of destruction of a root bundle - rupture and pulling out - can occur at the same. time. The values of shear strength increase calculated using this model were the lowest in case of beech and hornbeam roots, which had high tensile strength. It indicates that in the surface part of the profile (down to 0.2 m below the ground level), primarily in case of deciduous trees, the main mechanism of failure of the root bundle will be pulling out. However, this model requires the knowledge of a much greater number of geometrical parameters of roots and geotechnical parameters of soil, and additionally it is very sensitive to input data. Therefore, it seems practical to use the RBM2 model to assess the influence of roots on the soil shear strength increase, and in order to obtain safe results of calculations in the surface part of the profile, the Weibull shape coefficient equal to 1.0 can be assumed. On the other hand, the Wu-Waldron model can be used for the initial assessment of the shear strength increase of soil reinforced with roots in the situation, where the deformation properties of the root system and its interaction with the soil are not considered, although the values of the shear strength increase calculated using this model should be corrected and reduced by half. Test results indicate that in terms of slope stability the root systems of beech and hornbeam have the most favourable properties - their maximum effect of soil reinforcement in the profile to the depth of 0.5 m does not usually exceed 30 kPa, and to the depth of 1 m - 20 kPa. The root systems of conifers have the least impact on the slope reinforcement, usually increasing the soil shear strength by less than 5 kPa. These values coincide to a large extent with the range of shear strength increase obtained from the direct shear test as well as results of stability analysis given in literature and carried out as part of this work. The analysis of the literature indicates that the methods of measuring tree's root systems as well as their interpretation are very different, which often limits the possibilities of comparing test results. This indicates the need to systematize this type of tests and for this purpose a root distribution model (RDM) can be used, which can be integrated with any deformation bundle model (RBM). A combination of these two calculation models allows the range of soil reinforcement around trees to be determined and this information might be used in practice, while planning bioengineering procedures in areas exposed to surface mass movements. The functionality of this solution can be increased by considering the dynamics of plant develop¬ment in the calculations. This, however, requires conducting this type of research in order to obtain more data.
Частини книг з теми "Direct surface interactions":
1
Augusti-Tocco, Gabriella. "Cell Surface Components and Differentiation in Neuroblastoma Culture." In Cellular and Molecular Control of Direct Cell Interactions, 271–82. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4684-5092-7_14.
2
Schiele, Nathan R., David T. Corr, and Douglas B. Chrisey. "Laser Direct Writing of Idealized Cellular and Biologic Constructs for Tissue Engineering and Regenerative Medicine." In Laser-Surface Interactions for New Materials Production, 261–78. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03307-0_11.
3
Horiuchi, Shin. "Interfacial Phenomena in Adhesion and Adhesive Bonding Investigated by Electron Microscopy." In Interfacial Phenomena in Adhesion and Adhesive Bonding, 113–207. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-4456-9_3.
Анотація:
AbstractUsing electron microscopy techniques described in Chap. 2, we investigate interfacial phenomena in adhesion and adhesive bonding. Polymer–polymer interfaces formed via interdiffusion are visualized and characterized by EFTEM. Fractographic studies using high-resolution SEM investigate entanglements at the polymer–polymer interfaces, and the adhesion mechanism is discussed about the interfacial entanglements. The effect of surface treatments of polymers for adhesion improvement is studied in terms of the surface roughness and the chemical functionality of the adherend created by the surface pretreatments. We then describe the role of chemical interactions between polymers and metals on bonding by the analysis of fracture surfaces by the STEM-replica technique. Bonding mechanisms of adhesive bonding and recently developed direct bonding of metal and plastic are also investigated by STEM-EELS/ELNES and STEM-tomography. Finally, we evaluate the toughness and durability of adhesive joints between metal and carbon fiber reinforced plastics (CFRP) and discuss the durability of the adhesive bonding.
4
Yan Shan, Ang. "DNA Split Proximity Circuit for Visualizing Cell Surface Receptor Clustering—A Case Study Using Human Epidermal Growth Factor Receptor Family." In Engineering a Robust DNA Circuit for the Direct Detection of Biomolecular Interactions, 143–56. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-2188-7_8.
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Kim, Myung Hee, and Krishnendu Roy. "Ligand-functionalized Biomaterial Surfaces: Controlled Regulation of Signaling Pathways to Direct Cell Differentiation." In Biological Interactions on Materials Surfaces, 157–71. New York, NY: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-98161-1_8.
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Schmidt, Dominik, Florian Block, and Hans Gellersen. "A Comparison of Direct and Indirect Multi-touch Input for Large Surfaces." In Human-Computer Interaction – INTERACT 2009, 582–94. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03655-2_65.
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Israelachvili, J., D. Leckband, F. J. Schmitt, J. Zasadzinski, S. Walker, and S. Chiruvolu. "Direct Measurements of Specific Ligand-Receptor Interactions Between Model Membrane Surfaces." In Studying Cell Adhesion, 37–49. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-662-03008-0_3.
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Mangiavacchi, N., R. Gundlapalli, and R. Akhavan. "Direct Numerical Simulations of a Turbulent Jet Interacting with a Free Surface." In Fluid Mechanics and Its Applications, 351–56. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0457-9_63.
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Mertens, A., C. Brandl, J. Sannemann, A. Kant, M. Ph Mayer, and C. M. Schlick. "Visual and Haptic Perception of Surface Materials for Direct Skin Contact in Human–Machine Interaction." In Ambient Assisted Living, 249–67. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-37988-8_16.
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Giarlelis, Christos. "Geotechnical Aspects of Structural Failures." In Characteristic Seismic Failures of Buildings, 149–87. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/sed016.149.
Анотація:
<p>Strong seismic shaking is recognized as the direct cause of structural failures. In many cases, however, the factor that initiates the structural damage is ground failure or ground displacement. This chapter deals with the identification of all geotechnical related structural failures. Surface fault rupture has been a well-acknowledged cause of failures of structures built across or near the fault, which are increasing in frequency as the man-made environment constantly expands to new areas. Seismically induced rockfalls, landslides and slope failures have also been associ-ated with major disasters with an increasing frequency in some cases due to an expanding popu-lation, which encroach on areas with landslide risk or in other cases as result of the destruction of the natural environment (vegetation and water routes), which have protected these slopes in the past. Foundation damage may be a result of failure of shallow foundations or piles. In addition, although liquefaction and ground settlement are technically part of foundation failures, they are usually treated as separate, special cases. Retaining wall structures, usually considered as simple systems, may display a complex behaviour, which can be related to extensive seismic failures. Finally, not taking into account soil–structure interaction (SSI) may have a detrimental effect on the dynamic response of structures. Although SSI may never be the direct cause of a structural failure, it has proven to be, in several cases, the underlying reason for the analysis misconception that led to the failure.</p>
Тези доповідей конференцій з теми "Direct surface interactions":
1
D'Souza, Brian, and Andrew Ketsdever. "Direct Impulse Measurements of Ablation Processes from Laser-Surface Interactions." In 36th AIAA Plasmadynamics and Lasers Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2005. http://dx.doi.org/10.2514/6.2005-5172.
2
Marsh, Eugene P., Terry L. Gilton, Wolfgang Meier, Mark R. Schneider, and J. P. Cowin. "Electron-Transfer Mediated and Direct Surface Photochemistry: CH3Cl on Ni(111)." In Microphysics of Surfaces, Beams, and Adsorbates. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/msba.1989.tub2.
Анотація:
In the photochemistry of molecules on a metal or semiconductor, the surface can play a very important role by strongly perturbing, promoting or inhibiting the process.(1) Excitation to repulsive states is an important class of surface photochemical processes as they are: simple, bond specific, produce important reactive radicals, and are fast enough (5 to 100 fs) to largely escape electronic quenching due to surface interactions. However, charge transfer processes are still fast enough to perturb or dominate on this time scale.(2)
3
Shinn, Neal D. "Adsorbate Interactions and Poisoning on Cr(110)." In Microphysics of Surfaces, Beams, and Adsorbates. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/msba.1987.wc6.
Анотація:
The chemisorption of carbon monoxide and oxygen on Cr(110) at temperatures below 150K has been studied using photoemission, vibrational and Auger spectroscopies, and low energy electron diffraction (LEED). Direct evidence for co-adsorbate interactions which induce changes in the (1) molecular CO bonding to the chromium surface and (2) the CO dissociation energetics has been found. This work provides a microscopic picture of the "poisoning" of the Cr(110) surface for CO dissociation by electronegative oxygen atoms.
4
Kunz, R. R., T. E. Allen, and T. M. Mayer. "Thin Film Growth and Deposition by Low Energy Electron Stimulated Surface Chemistry." In Microphysics of Surfaces, Beams, and Adsorbates. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/msba.1987.tua2.
Анотація:
Direct materials processing by focused particle beams has received considerable attention in recent years. The electron beam, traditionally used for resist exposure in electron beam lithography applications, is among the candidates for direct materials modification. High energy electrons (>1keV) are not very chemically active due to small cross sections for inelastic scattering processes such as bond dissociation and attachment. Low energy electrons are expected to be much more efficient at stimulating chemical processes. In particular, secondary electrons produced by particle or photon bombardment of surfaces with kinetic energies of approx. 2-10 eV have large cross sections for attachment and dissociative electron attachment to many electronegative molecules. We have begun a general investigation of chemical reactivity and mechanisms of electron-adsorbate interactions leading to film growth and deposition. Prospects for applications to focussed beam, direct write materials processing are being explored.
5
Ganapathy, Harish, V. Emlin, Anant Narendra Parikh, and V. Sajith. "Experimental Investigation on Surface Particle Interactions During Pool Boiling of Nanofluids." In ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2011. http://dx.doi.org/10.1115/icnmm2011-58180.
Анотація:
The pool boiling characteristics of nanofluids is affected by the interaction between the nanoparticles and the heater surface which forms a sorption layer and this layer increases the surface wettability and thereby enhances the CHF. While deteriorated nucleate boiling has been attributed to the decreased activation of cavities due to the increased wettability, it fails to explain the enhanced performance observed by several researchers, which can be explained only by an increase in surface roughness and hence a direct increase in the number of cavities, thereby compensating for the increase in wettability. Attempts to characterize the roughness of heater surfaces have been restricted to magnified visualizations and intrusive probing. No non-intrusive tests have been reported on flat heaters, which are ideal to conduct surface analyses. The present work is aimed at conducting a non-intrusive experimental study to analyse the surface roughness modification due to the sorption layer on flat plate heaters. Experiments have been carried out using electro-stabilized aluminium oxide water based nanofluids of different concentrations with heaters having varying values of surface roughness. The burn-out heat flux was measured and the effect of sedimentation time was studied. The surface-particle interaction parameter (Ra/dp) was varied to capture the phenomena of plugging as well as splitting of nucleation sites. An experiment having a high value of the interaction parameter shows enhanced boiling performance and that with a value close to 1 shows deteriorated performance. Further it was seen that this behaviour is dependent on the particle concentration. Detailed surface characterization has been done using an optical measurements setup and atomic force microscopy. Boiling on nano-coated heaters has been investigated and presented as an effective solution to counter the disadvantageous transient boiling behavior of nanofluids.
6
Atwater, H. A., C. J. Tsai, and T. Vreeland. "Coherent Strain Changes in Si-Ge Alloys Grown By Ion-Assisted Molecular Beam Epitaxy." In The Microphysics of Surfaces: Beam-Induced Processes. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/msbip.1991.ma3.
Анотація:
Although low energy ion bombardment has been employed in various contexts during epitaxial growth, such as enhanced dopant incorporationfl], surface cleaning during plasma-enhanced chemical vapor deposition[2], and direct low energy ion beam deposition[3,4], key questions about the interaction of low energy ions with growing surfaces remain unanswered. Improved understanding of ion-surface interactions during growth may yield additional elements of control over epitaxial film structure, strain state, and composition. Of particular interest for high quality epitaxial films is the identification of the regime in which surface and near-surface processes, such as surface diffusion and incorporation at growth sites, can be enhanced at low temperatures while avoiding or controlling damage in the deposited films.
7
Adila, Ahmed S., Mahmoud Aboushanab, Ahmed Fathy, and Muhammad Arif. "An Experimental Investigation of Surface Chemistry of Rocks in the Presence of Surfactants." In GOTECH. SPE, 2024. http://dx.doi.org/10.2118/219143-ms.
Анотація:
Abstract Surfactant flooding is a well-known chemical enhanced oil recovery (cEOR) technique. However, surfactant surface chemistry and the associated interactions with rock surfaces are complex and have not been fully investigated. Here, we experimentally investigate the surface chemistry of 15 rock surfaces (10 carbonate and 5 sandstones) upon interaction with different types of surfactants, including cationic, anionic, non-ionic, and zwitterionic surfactants at different concentrations (before, at, and after the critical micelle concentration, CMC). The rock samples were examined using Scanning Electron Microscopy (SEM) to investigate their structure and surface morphology. To understand the interactions at the surfactant-mineral interface and surfactant behavior, the zeta potential measurements of surfactant-brine-rock emulsions were performed, while surface chemical functional groups were identified by Fourier-transform infrared (FTIR) spectroscopy. The zeta potential results show that both anionic (SDS) and cationic (CTAB) surfactants depict better stability, in carbonates and sandstones, compared to the non-ionic (Triton X-100) and zwitterionic (3- (N, N-Dimethylmyristylammonio) surfactants, which is due to the nature of the charge of each surfactant. Also, the FITR results indicate the existence of different chemical bonds and functional groups at different concentrations for each surfactant type, and the magnitude of these bonds differs as a function of rock type and mineralogy. For instance, the rock samples treated with CTAB cationic surfactant reveal the presence of C-O, Mg-C, and Ca-C groups at all concentrations. However, despite being present at all concentrations, these responses show different magnitudes at different surfactant concentrations. The results of this study provide valuable data set to understand the surfactant surface chemistry interactions with different carbonate and sandstone rock surfaces and thus have direct implications for chemical enhanced oil recovery.
8
Notley, Shannon M., and Lars Wågberg. "Direct Measurement of Attractive van der Waals Forces and Repulsive Electrostatic Forces between Regenerated Cellulose Surfaces in an Aqueous Environment." In Advances in Paper Science and Technology, edited by S. J. I’Anson. Fundamental Research Committee (FRC), Manchester, 2005. http://dx.doi.org/10.15376/frc.2005.2.1337.
Анотація:
Using the colloidal probe technique, the interaction between carboxymethylated cellulose films and a cellulose sphere was studied. At low pH (pH 3.5), the interaction was dominated by dispersion forces. This was due to the low dissociation of carboxyl groups within the film at pH 3.5. However, at pH greater than 5, the interaction was dominated by an electrostatic repulsion. The increase in pH had the two-fold effect of completely dissociating the charged groups as well as causing appreciable swelling of the film leading to a decrease in the van der Waals component of the interaction. From these results it can be concluded that these cellulose films are suitable for a range of surface forces measurements including electrostatic, van der Waals’, steric and adhesion forces. Furthermore, the measurement of forces using the colloidal probe technique can be extended to inorganic particles as well as for interactions between surfaces in the presence of for example wet and dry strength agents and other materials relevant to the paper-making industry.
9
Kunkle, Claire M., and Van P. Carey. "Metrics for Quantifying Surface Wetting Effects on Vaporization Processes at Nanostructured Hydrophilic Surfaces." In ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ht2016-7203.
Анотація:
A static contact angle is most often used as a means of quantifying the wetting characteristics of the liquid phase in vaporization processes at a solid surface. This metric is often convenient to measure and intuitive in its interpretation, but when a surface is superhydrophilic, the resulting low contact angles are difficult to measure accurately from photographs of sessile droplet profiles or contact line regions. For droplets at ultra low contact angles, small changes of contact angle can produce very large changes in wetted surface area, which makes small uncertainties in contact angle result in large uncertainties in wetted area. For hydrophilic nanostructured surfaces, another disadvantage is that the relationship of the macroscopic (apparent) contact angle to the nanoscale interaction of the liquid and vapor contact line with the nanostructured surface is not always clear. In this study, a new wetting metric based on spreading characteristics of sessile droplets is proposed that can be easily measured for hydrophilic surfaces. This metric also has the advantage that it is a more direct and sensitive indicator of how a droplet spreads on the surface. The spread area directly impacts heat transfer interactions between the droplet and the surface, therefore affecting evaporation time. Consequently, a metric that more directly illustrates the spread area provides an indication of how the wetting will affect these mechanisms. Use of the proposed new metric is explored in the context of evaporation and boiling applications with superhydrophilic surfaces. Characteristics of this metric are also compared to static contact angle and other choices of wetting metrics suggested in earlier studies, such as dynamic advancing and receding contact angles, and spreading coefficients. The effects of nanoscale structure and/or roughness on the proposed wetting metric are analyzed in detail. A model is developed that predicts the dependence of the proposed wetting parameter on intrinsic material wettability for rough, nano-structured surfaces. The model results demonstrate that the proposed metric is a more sensitive indicator of macroscopic wetting behavior than apparent contact angle when the surface is superhydrophilic. This characteristic of the proposed new metric is shown to have advantages over other wetting metrics in the specific case of superhydrophilic nanostructured surfaces. Application of the proposed wetting metric is demonstrated for some example nanostructured surfaces. The results of our study indicate that this proposed new metric can be particularly useful for characterizing the effects of variable wetting on vaporization processes on highly wetted nanostructured surfaces.
10
Yan, Hongmei, Yuming Liu, and Yile Li. "Unstable Motion of a Floating Structure in Surface Waves." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49621.
Анотація:
Unstable resonant heave and pitch motions of a floating deep draft platform, under the action of a regular wave with the frequency equal to the sum of the heave and pitch natural frequencies, can be developed by nonlinear instability (Liu, Yan & Yung 2010). The instability is associated with difference-frequency interactions between the body motion and the ambient wave. In this work, we study the effect of the nonlinear instability upon floating platforms with relatively shallow drafts whose wave damping at heave/pitch natural frequencies may not be small. Direct time-domain numerical simulations of wave-structure interactions, which can take into account different levels of nonlinearity effects, are applied to understand the characteristics of the unstable coupled heave/pitch (or heave/roll) resonant motion and its dependence on the key physical factors. In particular, it is found that such a nonlinear instability at other wave conditions involving sum-frequency interactions between the body motion and the ambient wave can also occur. For practical applications, long-time nonlinear simulations with irregular waves are also performed. The results show that depending on the sea conditions and damping in the system, the unstable resonant motion associated with the nonlinear instability can be significant for platforms with shallow drafts.
Звіти організацій з теми "Direct surface interactions":
1
D'Souza, Brian, and Andrew Ketsdever. Direct Impulse Measurements of Ablation Processes from Laser-Surface Interactions. Fort Belvoir, VA: Defense Technical Information Center, May 2005. http://dx.doi.org/10.21236/ada435844.
2
Procassini, R. J., and B. I. Cohen. The DIPSI (Direct Implicit Plasma Surface Interactions) computer code user's manual. Office of Scientific and Technical Information (OSTI), June 1990. http://dx.doi.org/10.2172/7185616.
3
Chefetz, Benny, Baoshan Xing, and Yona Chen. Interactions of engineered nanoparticles with dissolved organic matter (DOM) and organic contaminants in water. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7699863.bard.
Анотація:
Background: Engineered carbon nanotubes (CNTs) are expected to be increasingly released into the environment with the rapid increase in their production and use. The discharged CNTs may interact with coexisting contaminants and subsequently change environmental behaviors and ecological effects of both the CNTs themselves and the contaminants. Dissolved organic matter (DOM) plays a critical role in the transport of CNTs in the aquatic environment, affecting both CNT's surface properties through adsorption, and its colloidal stability in solution. Therefore, CNT-bound DOM complexes may interact with coexisting contaminants, thus affecting their environmental fate. With increasing production and use of CNTs, there is an increasing risk that humans could be exposed to CNTs mainly through ingestion and inhalation. Since CNTs can be carriers of contaminants due to their high adsorption affinity and capacity, the distribution of these nanoparticles in the environment holds a potential environmental and health risk. Project objectives: The overall goal of this project was to gain a better understanding of the environmental behavior of engineered nanoparticles with DOM and organic pollutant in aqueous systems. The scope of this study includes: characterizing various types of engineered nanoparticles and their interaction with DOM; binding studies of organic contaminants by nanoparticles and DOM-nanoparticle complexes; and examining interactions in DOM-nanoparticles-contaminant systems. Major conclusions, solutions and achievements: DOM has a pronounced effect on colloidal stability of CNTs in solution and on their surface chemistry and reactivity toward associated contaminants. The structure and chemical makeup of both CNTs and DOM determine their interactions and nature of formed complexes. CNTs, contaminants and DOM can co-occur in the aquatic environment. The occurrence of co-contaminants, as well as of co-introduction of DOM, was found to suppress the adsorption of organic contaminants to CNTs through both competition over adsorption sites and direct interactions in solution. Furthermore, the release of residual contaminants from CNTs could be enhanced by biomolecules found in the digestive as well as the respiratory tracts, thus increasing the bioaccessibility of adsorbed contaminants and possibly the overall toxicity of contaminant-associated CNTs. Contaminant desorption could be promoted by both solubilization and sorptive competition by biological surfactants. Scientific and agricultural implications: The information gained in the current project may assist in predicting the transport and fate of both CNTs and associated contaminants in the natural environment. Furthermore, the results imply a serious health risk from contaminant-associated CNTs.
4
McClure, Michael A., Yitzhak Spiegel, David M. Bird, R. Salomon, and R. H. C. Curtis. Functional Analysis of Root-Knot Nematode Surface Coat Proteins to Develop Rational Targets for Plantibodies. United States Department of Agriculture, October 2001. http://dx.doi.org/10.32747/2001.7575284.bard.
Анотація:
The goal of this research was to provide a better understanding of the interface between root-knot nematodes, Meloidogyne spp., and their host in order to develop rational targets for plantibodies and other novel methods of nematode control directed against the nematode surface coat (SC). Specific objectives were: 1. To produce additional monoclonal SC antibodies for use in Objectives 2, 3, and 4 and as candidates for development of plantibodies. 2. To determine the production and distribution of SC proteins during the infection process. 3. To use biochemical and immunological methods to perturbate the root-knot nematode SC in order to identify SC components that will serve as targets for rationally designed plantibodies. 4. To develop SC-mutant nematodes as additional tools for defining the role of the SC during infection. The external cuticular layer of nematodes is the epicuticle. In many nematodes, it is covered by a fuzzy material termed "surface coat" (SC). Since the SC is the outermost layer, it may playa role in the interaction between the nematode and its surroundings during all life stages in soil and during pathogenesis. The SC is composed mainly of proteins, carbohydrates (which can be part of glycoproteins), and lipids. SC proteins and glycoproteins have been labeled and extracted from preparasitic second-stage juveniles and adult females of Meloidogyne and specific antibodies have been raised against surface antigens. Antibodies can be used to gain more information about surface function and to isolate genes encoding for surface antigens. Characterization of surface antigens and their roles in different life-stages may be an important step towards the development of alternative control. Nevertheless, the role of the plant- parasitic nematode's surface in plant-nematode interaction is still not understood. Carbohydrates or carbohydrate-recognition domains (CROs) on the nematode surface may interact with CROs or carbohydrate molecules, on root surfaces or exudates, or be active after the nematode has penetrated into the root. Surface antigens undoubtedly play an important role in interactions with microorganisms that adhere to the nematodes. Polyclonal (PC) and monoclonal (MC) antibodies raised against Meloidogyne javanica, M. incognita and other plant-parasitic nematodes, were used to characterize the surface coat and secreted-excreted products of M. javanica and M. incognita. Some of the MC and PC antibodies raised against M. incognita showed cross-reactivity with the surface coat of M. javanica. Further characterization, in planta, of the epitopes recognized by the antibodies, showed that they were present in the parasitic juvenile stages and that the surface coat is shed during root penetration by the nematode and its migration between root cells. At the molecular level, we have followed two lines of experimentation. The first has been to identify genes encoding surface coat (SC) molecules, and we have isolated and characterized a small family of mucin genes from M. incognita. Our second approach has been to study host genes that respond to the nematode, and in particular, to the SC. Our previous work has identified a large suite of genes expressed in Lycopersicon esculentum giant cells, including the partial cDNA clone DB#131, which encodes a serine/threonine protein kinase. Isolation and predicted translation of the mature cDNA revealed a frame shift mutation in the translated region of nematode sensitive plants. By using primers homologous to conserved region of DB#131 we have identified the orthologues from three (nematode-resistant) Lycopersicon peruvianum strains and found that these plants lacked the mutation.
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Gottlieb, Yuval, Bradley Mullens, and Richard Stouthamer. investigation of the role of bacterial symbionts in regulating the biology and vector competence of Culicoides vectors of animal viruses. United States Department of Agriculture, June 2015. http://dx.doi.org/10.32747/2015.7699865.bard.
Анотація:
Symbiotic bacteria have been shown to influence host reproduction and defense against biotic and abiotic stressors, and this relates to possible development of a symbiont-based control strategy. This project was based on the hypothesis that symbionts have a significant impact on Culicoides fitness and vector competence for animal viruses. The original objectives in our proposal were: 1. Molecular identification and localization of the newly-discovered symbiotic bacteria within C. imicola and C. schultzei in Israel and C. sonorensis in California. 2. Determination of the prevalence of symbiotic bacteria within different vector Culicoides populations. 3. Documentation of specific symbiont effects on vector reproduction and defense: 3a) test for cytoplasmic incompatibility in Cardinium-infected species; 3b) experimentally evaluate the role of the symbiont on infection or parasitism by key Culicoides natural enemies (iridescent virus and mermithid nematode). 4. Testing the role(s) of the symbionts in possible protection against infection of vector Culicoides by BTV. According to preliminary findings and difficulties in performing experimental procedures performed in other insect symbiosis systems where insect host cultures are easily maintained, we modified the last two objectives as follows: Obj. 3, we tested how symbionts affected general fitness of Israeli Culicoides species, and thoroughly described and evaluated the correlation between American Culicoides and their bacterial communities in the field. We also tried alternative methods to test symbiont-Culicoides interactions and launched studies to characterize low-temperature stress tolerances of the main US vector, which may be related to symbionts. Obj. 4, we tested the correlation between EHDV (instead of BTV) aquisition and Cardinium infection. Culicoides-bornearboviral diseases are emerging or re-emerging worldwide, causing direct and indirect economic losses as well as reduction in animal welfare. One novel strategy to reduce insects’ vectorial capacity is by manipulating specific symbionts to affect vector fitness or performance of the disease agent within. Little was known on the bacterial tenants occupying various Culicoides species, and thus, this project was initiated with the above aims. During this project, we were able to describe the symbiont Cardinium and whole bacterial communities in Israeli and American Culicoides species respectively. We showed that Cardinium infection prevalence is determined by land surface temperature, and this may be important to the larval stage. We also showed no patent significant effect of Cardinium on adult fitness parameters. We showed that the bacterial community in C. sonorensis varies significantly with the host’s developmental stage, but it varies little across multiple wastewater pond environments. This may indicate some specific biological interactions and allowed us to describe a “core microbiome” for C. sonorensis. The final set of analyses that include habitat sample is currently done, in order to separate the more intimately-associated bacteria from those inhabiting the gut contents or cuticle surface (which also could be important). We were also able to carefully study other biological aspects of Culicoides and were able to discriminate two species in C. schultzei group in Israel, and to investigate low temperature tolerances of C. sonorensis that may be related to symbionts. Scientific implications include the establishment of bacterial identification and interactions in Culicoides (our work is cited in other bacteria-Culicoides studies), the development molecular identification of C. schultzei group, and the detailed description of the microbiome of the immature and matched adult stages of C. sonorensis. Agricultural implications include understanding of intrinsic factors that govern Culicoides biology and population regulation, which may be relevant for vector control or reduction in pathogen transmission. Being able to precisely identify Culicoides species is central to understanding Culicoides borne disease epidemiology.
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Wilkowski. L51487 Predict the Interaction of Fracture Toughness and Constraint Effects for Surface Cracked Pipe. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), April 1985. http://dx.doi.org/10.55274/r0010596.
Анотація:
This report summarizes a program designed to quantify the disagreement between the standard t x 2t bend specimen and surface-cracked pipe data. The effect of untracked ligament length on upper-shelf toughness was also investigated. Ultimately, the findings will have application to pipeline girth welds. But in this first step, unwelded line-pipe steel specimens were used throughout this investigation. Obviously, weld metal specimen data would be more directly applicable to welded pipe. However, weld metal test data exhibit more scatter than base metal data (largely due to material non-homogeneity). This scatter could cloud the general data trends under investigation. Consequently, base metal specimens were used to more clearly establish these trends. This will form a basis for further investigations on weld metals.
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Lokke, Arnkjell, and Anil Chopra. Direct-Finite-Element Method for Nonlinear Earthquake Analysis of Concrete Dams Including Dam–Water–Foundation Rock Interaction. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, March 2019. http://dx.doi.org/10.55461/crjy2161.
Анотація:
Evaluating the seismic performance of concrete dams requires nonlinear dynamic analysis of two- or three-dimensional dam–water–foundation rock systems that include all the factors known to be significant in the earthquake response of dams. Such analyses are greatly complicated by interaction between the structure, the impounded reservoir and the deformable foundation rock that supports it, and the fact that the fluid and foundation domains extend to large distances. Presented in this report is the development of a direct finite-element (FE) method for nonlinear earthquake analysis of two- and three-dimensional dam–water–foundation rock systems. The analysis procedure applies standard viscous-damper absorbing boundaries to model the semi-unbounded fluid and foundation domains, and specifies at these boundaries effective earthquake forces determined from a ground motion defined at a control point on the ground surface. This report is organized in three parts, with a common notation list, references, and appendices at the end of the report. Part I develops the direct FE method for 2D dam–water–foundation rock systems. The underlying analytical framework of treating dam–water–foundation rock interaction as a scattering problem, wherein the dam perturbs an assumed "free-field" state of the system, is presented, and by applying these concepts to a bounded FE model with viscous-damper boundaries to truncate the semi-unbounded domains, the analysis procedure is derived. Step-by-step procedures for computing effective earthquake forces from analysis of two 1D free-field systems are presented, and the procedure is validated by computing frequency response functions and transient response of an idealized dam–water–foundation rock system and comparing against independent benchmark results. This direct FE method is generalized to 3D systems in Part II of this report. While the fundamental concepts of treating interaction as a scattering problem are similar for 2D and 3D systems, the derivation and implementation of the method for 3D systems is much more involved. Effective earthquake forces must now be computed by analyzing a set of 1D and 2D systems derived from the boundaries of the free-field systems, which requires extensive book-keeping and data transfer for large 3D models. To reduce these requirements and facilitate implementation of the direct FE method for 3D systems, convenient simplifications of the procedure are proposed and their effectiveness demonstrated. Part III of the report proposes to use the direct FE method for conducting the large number of nonlinear response history analyses (RHAs) required for performance-based earthquake engineering (PBEE) of concrete dams, and discusses practical modeling considerations for two of the most influential aspects of these analyses: nonlinear mechanisms and energy dissipation (damping). The findings have broad implications for modeling of energy dissipation and calibration of damping values for concrete dam analyses. At the end of Part III, the direct FE method is implemented with a commercial FE program and used to compute the nonlinear response of an actual arch dam. These nonlinear results, although limited in their scope, demonstrate the capabilities and effectiveness of the direct FE method to compute the types of nonlinear engineering response quantities required for PBEE of concrete dams.
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Parkins. L51806 Effects of Hydrogen on Low-pH Stress Corrosion Crack Growth. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), July 1998. http://dx.doi.org/10.55274/r0010142.
Анотація:
There is circumstantial evidence of hydrogen playing a role in, so called, low pH SCC of pipeline steel, but direct evidence for such is lacking. Resolution of this situation is of practical importance because of its implications for modeling. Thus, existing models for high pH SCC of pipelines are based upon a dissolution controlled mechanism of crack growth, but such models will not be applicable to low pH SCC if hydrogen is involved with the latter. Measurements have been made of the permeation of hydrogen into X52 and X60 pipeline steels at various potetials while exposed to a simulated ground water containing different amounts of carbon dioxide, related to the conditions thought to be associated with transgranular stress corrosion cracking of pipelines. As a consequence of these measurements it is now known unequivocally that hydrogen enters the steel for all such solutions over wide ranges of potential, including those most likely involved in the cracking of pipelines, and with such entry enhanced as the amount of carbon dioxide present in the solution increased. For a given set of environmental conditions, it was found that films on the surface of the pipe, such as may exist in service conditions, could hinder, but not prevent, the ingress of hydrogen. Hydrogen in steel is usually regarded as being trapped at dislocations, grain boundaries or interfaces between the matrix and second phase particles and measurements relating to such indicate that the X60 steel contains appreciably fewer traps than the X52 steel for equivalent charging conditions. However, the trapped hydrogen was found to have no significant influence on the ductility of the steels when subsequently tested in air, although the ductility was impaired by thxe continued ingress of hydrogen when equivalent tests were conducted in the presence of the charging solution. No convincing evidence has been obtained for the ingress of hydrogen into the steels facilitating the early stages of plasticity under exposure conditions relating to those involved in low pH stress corrossion cracking. The most probable mechanism of stress corrosion crack growth in pipeline steel in the solutions studied and at potentials likely to obtain in service involves both dissolution and hydrogen ingress to the steel, although the interactions of those two factors in the fracture process remain speculative.
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Dinovitzer, Aaron. PR-214-154503-R01 Pipeline Strains Induced by Slope Movement. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), August 2019. http://dx.doi.org/10.55274/r0011609.
Анотація:
Pipeline integrity may be affected by the action of the external soil loads that can be generated by ground movements or slope failures and the structural integrity threat of these geotechnical failures is not well understood. The threat presented to a pipeline by a localized slope failure is not directly related to magnitude of the soil movement involved, but related to the stress and strains induced in the pipeline by the moving soil block. This project demonstrated and applied advanced pipe-soil interaction numerical modeling tools in the assessment of slope movements directed long the pipeline axis. The geotechnical hazard assessments completed in this project provide a conservative means of estimating the pipeline axial strain accumulation resulting from slope movements. These modeling results are presented such that an understanding of the influence of pipeline, slope and operational parameters on strain accumulation is demonstrated and the relative importance of each parameter is demonstrated. The relationship between surface expression of a geotechnical event and the subsurface parameters to facilitate conservative characterization of the event is defined. The data describing axial strain as a function of ground movement magnitude presented in this project may be compared to the axial strain capacity (resistance) engineering tools to evaluate the significance of slope movements on pipeline integrity.
10
Lever, James, Emily Asenath-Smith, Susan Taylor, and Austin Lines. Assessing the mechanisms thought to govern ice and snow friction and their interplay with substrate brittle behavior. Engineer Research and Development Center (U.S.), December 2021. http://dx.doi.org/10.21079/1168142742.
Анотація:
Sliding friction on ice and snow is characteristically low at temperatures common on Earth’s surface. This slipperiness underlies efficient sleds, winter sports, and the need for specialized tires. Friction can also play micro-mechanical role affecting ice compressive and crushing strengths. Researchers have proposed several mechanisms thought to govern ice and snow friction, but directly validating the underlying mechanics has been difficult. This may be changing, as instruments capable of micro-scale measurements and imaging are now being brought to bear on friction studies. Nevertheless, given the broad regimes of practical interest (interaction length, temperature, speed, pressure, slider properties, etc.), it may be unrealistic to expect that a single mechanism accounts for why ice and snow are slippery. Because bulk ice, and the ice grains that constitute snow, are solids near their melting point at terrestrial temperatures, most research has focused on whether a lubricating water film forms at the interface with a slider. However, ice is extremely brittle, and dry-contact abrasion and wear at the front of sliders could prevent or delay a transition to lubricated contact. Also, water is a poor lubricant, and lubricating films thick enough to separate surface asperities may not form for many systems of interest. This article aims to assess our knowledge of the mechanics underlying ice and snow friction.