Interfacial assembly of nanorods: smectic alignment and multilayer stacking

Nanoscale ◽  
2021 ◽  
Author(s):  
Yi-Ting Cheng ◽  
Heng-Kwong Tsao ◽  
Yu-Jane Sheng
Keyword(s):  
Surface Modification ◽  
Large Scale ◽  
Spatial Arrangement ◽  
Interfacial Assembly ◽  
Orientation Ordering

Large-scale spatial arrangement and orientation ordering of nanorods assembly on substrates is critical for nanodevice fabrication. However, complicated processes and templates or surface modification of nanorods are often required. In...

Large-scale mapping of the catenas vegetation in Subarctic tundra

1995 ◽  
pp. 3-21
Author(s):  
S. S. Kholod
Keyword(s):  
Spatial Distribution ◽  
Vegetation Cover ◽  
Large Scale ◽  
Block Diagram ◽  
Abiotic Factors ◽  
Ecological Factors ◽  
Spatial Arrangement ◽  
Geological Time ◽  
Ecological Barriers ◽  
Functional Zones

One of the most difficult tasks in large-scale vegetation mapping is the clarification of mechanisms of the internal integration of vegetation cover territorial units. Traditional way of searching such mechanisms is the study of ecological factors controlling the space heterogeneity of vegetation cover. In essence, this is autecological analysis of vegetation. We propose another way of searching the mechanisms of territorial integration of vegetation. It is connected with intracoenotic interrelation, in particular, with the changing role of edificator synusium in a community along the altitudinal gradient. This way of searching is illustrated in the model-plot in subarctic tundra of Central Chukotka. Our further suggestion concerns the way of depicting these mechanisms on large-scale vegetation map. As a model object we chose the catena, that is the landscape formation including all geomorphjc positions of a slope, joint by the process of moving the material down the slope. The process of peneplanation of a mountain system for a long geological time favours to the levelling the lower (accumulative) parts of slopes. The colonization of these parts of the slope by the vegetation variants, corresponding to the lowest part of catena is the result of peneplanation. Vegetation of this part of catena makes a certain biogeocoenotic work which is the levelling of the small infralandscape limits and of the boundaries in vegetation cover. This process we name as the continualization on catena. In this process the variants of vegetation in the lower part of catena are being broken into separate synusiums. This is the process of decumbation of layers described by V. B. Sochava. Up to the slope the edificator power of the shrub synusiums sharply decreases. Moss and herb synusium have "to seek" the habitats similar to those under the shrub canopy. The competition between the synusium arises resulting in arrangement of a certain spatial assemblage of vegetation cover elements. In such assemblage the position of each element is determined by both biotic (interrelation with other coenotic elements) and abiotic (presence of appropriate habitats) factors. Taking into account the biogeocoenotic character of the process of continualization on catena we name such spatial assemblage an exolutionary-biogeocoenotic series. The space within each evolutionary-biogeocoenotic series is divided by ecological barriers into some functional zones. In each of the such zones the struggle between synusiums has its individual expression and direction. In the start zone of catena (extensive pediment) the interrelations of synusiums and layers control the mutual spatial arrangement of these elements at the largest extent. Here, as a rule, there predominate edificator synusiums of low and dwarfshrubs. In the first order limit zone (the bend of pediment to the above part of the slope) one-species herb and moss synusiums, oftenly substituting each other in similar habitats, get prevalence. In the zone of active colonization of slope (denudation slope) the coenotic factor has the least role in the spatial distribution of the vegetation cover elements. In particular, phytocoenotic interactions take place only within separate microcoenoses of herbs, mosses and lichens. In the zone of the attenuation of continualization process (the upper most parts of slope, crests) phytocoenotic interactions are almost absent and the spatial distribution of vegetation cover elements depends exclusively on the abiotic factors. The principal scheme of the distribution of vegetation cover elements and the disposition of functional zones on catena are shown on block-diagram (fig. 1).

scholarly journals Design and Validation of an Adjustable Large-Scale Solar Simulator

2021 ◽  
Vol 11 (4) ◽  
pp. 1964
Author(s):  
Daniele Colarossi ◽  
Eleonora Tagliolini ◽  
Paolo Principi ◽  
Roberto Fioretti
Keyword(s):  
Large Scale ◽  
Design Procedure ◽  
Spatial Arrangement ◽  
Luminous Flux ◽  
International Electrotechnical Commission ◽  
Solar Simulator ◽  
Class A ◽  
Pv Panel ◽  
Temporal Instability ◽  
Class B

This work presents an adjustable large-scale solar simulator based on metal halide lamps. The design procedure is described with regards to the construction and spatial arrangement of the lamps and the designed optical system. Rotation and translation of the lamp array allow setting the direction and the intensity of the luminous flux on the horizontal plane. To validate the built model, irradiance nonuniformity and temporal instability tests were carried out assigning Class A, B, or C for each test, according to the International Electrotechnical Commission (IEC) standards requirements. The simulator meets the Class C standards on a 200 × 90 cm test plane, Class B on 170 × 80 cm, and Class A on 80 × 40 cm. The temporal instability returns Class A results for all the measured points. Lastly, a PV panel is characterized by tracing the I–V curve under simulated radiation, under outdoor natural sunlight, and with a numerical method. The results show a good approximation.

Plasma Surface Modification of Silica and its Application in Epoxy Molding Compounds for Large-Scale Integrated Circuits Packaging

2010 ◽  
Vol 158 ◽  
pp. 184-188 ◽  
Author(s):  
Ming Shan Yang ◽  
Lin Kai Li ◽  
Jian Guo Zhang
Keyword(s):  
Surface Modification ◽  
Acrylic Acid ◽  
Integrated Circuits ◽  
Plasma Polymerization ◽  
High Speed ◽  
Large Scale ◽  
Treatment Time ◽  
Rf Plasma ◽  
Formaldehyde Resin ◽  
Molding Compounds

The surface modification of silica for epoxy molding compounds (EMC) was conducted by plasma polymerization using RF plasma (13.56MPa), and the modification factors such as plasma power, gas pressure and treatment time were investigated systematically in this paper. The monomers utilized for the plasma polymer coatings were pyrrole, 1,3-diaminopropane, acrylic acid and urea. The plasma polymerization coating of silica was characterized by FTIR, contact angle. Using the silica treated by plasma as filler, ortho-cresol novolac epoxy as main resin, novolac phenolic-formaldehyde resin as cross-linking agent and 2-methylmizole as curing accelerating agent, the EMCs used for the packaging of large-scale integrated circuits were prepared by high-speed pre-mixture and twin roller mixing technology. The results have shown that the surface of silica can be coated by plasma polymerization of pyrrole, 1,3-diaminopropane, acrylic acid and urea, and the comprehensive properties of EMC were improved.

Experiments on mixing due to chaotic advection in a cavity

1989 ◽  
Vol 209 ◽  
pp. 463-499 ◽  
Author(s):  
C. W. Leong ◽  
J. M. Ottino
Keyword(s):  
Large Scale ◽  
Spatial Arrangement ◽  
Periodic Points ◽  
Chaotic Advection ◽  
Two Dimensional ◽  
Complex Behaviour ◽  
Chaotic Flows ◽  
Regular Time ◽  
Slow Flows ◽  
Time Periodic

Chaotic mixing of fluids in slow flows is ubiquitous but incompletely understood. However, relatively simple experiments provide a wealth of information regarding mixing mechanisms and indicate the need for complementary theoretical developments in dynamical systems. In this work we presnt a versatile cavity flow apparatus, capable of producing a variety of two-dimensional velocity fields, and use it to conduct a detailed experimental study of mixing in low-Reynolds-number flows. Since the goal is detailed understanding, only two time-periodic co-rotating flows induced by wall motions are considered: one continuous and the other discontinuous. Both types of flows produce exponential growth of intermaterial area, as expected from chaotic flows, and a mixture of islands and chaotic regions. A procedure for identifying periodic points and determining their movements is presented as well as how to make meaningful comparisons between periodic flows. We observe that periodic points move very much as a planetary system; planets (hyperbolic points) have moons (elliptic points) with twice the period of the planets; furthermore the spatial arrangement of periodic points becomes symmetric at regular time intervals. Detailed analyses reveal complex behaviour: birth, bifurcation, and collapse of islands; formation and periodic motion of coherent structures, such as islands and large-scale folds. However, the richness and complexity of the results obtained indicate that these two-dimensional time-periodic systems are far from completely understood and that other wall motions might deserve a similar level of scrutiny.

Crystal-Plasticity Simulation of the Evolution of the Matt Surface in Pack Rolling of Aluminium Foil

2014 ◽  
Vol 794-796 ◽  
pp. 553-558 ◽  
Author(s):  
Olaf Engler ◽  
Galyna Laptyeva ◽  
Holger Aretz ◽  
Gernot Nitzsche
Keyword(s):  
Crystal Plasticity ◽  
Large Scale ◽  
Rolling Texture ◽  
Spatial Arrangement ◽  
Alloy Sheet ◽  
Aluminium Foil ◽  
Strain Anisotropy ◽  
Recent Project ◽  
Final Rolling ◽  
Different Characteristics

Aluminium foil is rolled double-layered during the final rolling pass. When the sheets are later separated, the inside surface is dull and the outside surface is shiny. The matt inner side is characterized by significant surface corrugations which are believed to be a precursor for the initiation of fracture upon a subsequent forming operation. Therefore, understanding of the development of the matt side of Al foil will help to control and, eventually, improve the properties of Al foil. It was the goal of the present study to correlate the development of the matt side with the spatial arrangement of the crystallographic orientations of the foil rolling texture. This approach builds on a recent project to correlate the phenomenon of roping in AA 6xxx alloy sheet for car body applications to the occurrence of band-like clusters of grains with similar crystallographic orientation. Large-scale orientation maps obtained by electron back-scattered diffraction (EBSD) were input into a visco-plastic self-consistent crystal-plasticity model to analyse the strain anisotropy caused by the spatial distribution of the various rolling texture components. The new model is applied to several Al foils with different characteristics of the matt side.

Robust Design of Cellular Materials With Topological and Dimensional Imperfections

2006 ◽  
Vol 128 (6) ◽  
pp. 1285-1297 ◽  
Author(s):  
Carolyn Conner Seepersad ◽  
Janet K. Allen ◽  
David L. McDowell ◽  
Farrokh Mistree
Keyword(s):  
Large Scale ◽  
Design Method ◽  
Spatial Arrangement ◽  
Cellular Materials ◽  
Topology Design ◽  
Material Structure ◽  
Length Scales ◽  
Performance Requirements ◽  
Key Aspects ◽  
The Impact

A paradigm shift is underway in which the classical materials selection approach in engineering design is being replaced by the design of material structure and processing paths on a hierarchy of length scales for multifunctional performance requirements. In this paper, the focus is on designing mesoscopic material topology—the spatial arrangement of solid phases and voids on length scales larger than microstructures but smaller than the characteristic dimensions of an overall product. A robust topology design method is presented for designing materials on mesoscopic scales by topologically and parametrically tailoring them to achieve properties that are superior to those of standard or heuristic designs, customized for large-scale applications, and less sensitive to imperfections in the material. Imperfections are observed regularly in cellular material mesostructure and other classes of materials because of the stochastic influence of feasible processing paths. The robust topology design method allows us to consider these imperfections explicitly in a materials design process. As part of the method, guidelines are established for modeling dimensional and topological imperfections, such as tolerances and cracked cell walls, as deviations from intended material structure. Also, as part of the method, robust topology design problems are formulated as compromise Decision Support Problems, and local Taylor-series approximations and strategic experimentation techniques are established for evaluating the impact of dimensional and topological imperfections, respectively, on material properties. Key aspects of the approach are demonstrated by designing ordered, prismatic cellular materials with customized elastic properties that are robust to dimensional tolerances and topological imperfections.

Surface modification using interfacial assembly of the Streptomyces chaplin proteins

2014 ◽  
Vol 98 (10) ◽  
pp. 4491-4501 ◽  
Author(s):  
David Matthias Ekkers ◽  
Dennis Claessen ◽  
Federica Galli ◽  
Eize Stamhuis
Keyword(s):  
Surface Modification ◽  
Interfacial Assembly

scholarly journals Effects of topography and surface roughness in analyses of landscape structure - A proposal to modify the existing set of landscape metrics

2008 ◽  
Vol 3 ◽  
pp. 1-14 ◽  
Author(s):  
Sebastian Hoechstetter ◽  
Ulrich Walz ◽  
Le Hai Dang ◽  
Nguyen Xuan Thinh
Keyword(s):  
Landscape Metrics ◽  
Large Scale ◽  
Explanatory Power ◽  
High Sensitivity ◽  
Spatial Arrangement ◽  
Surface Metrology ◽  
Realistic Assessment ◽  
Basic Approaches ◽  
Shape Metrics ◽  
Neutral Landscapes

Topography and relief variability play a key role in ecosystem functioning and structuring. However, the most commonly used concept to relate pattern to process in landscape ecology, the so-called patch-corridor-matrix model, perceives the landscape as a planimetric surface. As a consequence, landscape metrics, used as numerical descriptors of the spatial arrangement of landscape mosaics, generally do not allow for the examination of terrain characteristics and may even produce erroneous results, especially in mountainous areas. This brief methodological study provides basic approaches to include relief properties into large-scale landscape analyses, including the calculation of standard landscape metrics on the basis of "true" surface geometries and the application of roughness parameters derived from surface metrology. The methods are tested for their explanatory power using neutral landscapes and simulated elevation models. The results reveal that area and distance metrics possess a high sensitivity to terrain complexity, while the values of shape metrics change only slightly when surface geometries are considered for their calculation. In summary, the proposed methods prove to be a valuable extension of the existing set of metrics mainly in "rough" landscape sections, allowing for a more realistic assessment of the spatial structure.

scholarly journals Aqueous dispersion and tuning surface charges of polytetrafluoroethylene particles by bioinspired polydopamine–polyethyleneimine coating via one-step method

2021 ◽  
Vol 8 (8) ◽  
pp. 210582
Author(s):  
Manjit Singh Grewal ◽  
Hiroya Abe ◽  
Yasutaka Matsuo ◽  
Hiroshi Yabu
Keyword(s):  
Surface Modification ◽  
Large Scale ◽  
Surface Coverage ◽  
Aqueous Dispersion ◽  
Surface Charges ◽  
Step Method ◽  
Reaction Solution ◽  
Uniform Dispersion ◽  
One Step ◽  
Inert Surfaces

We propose a surface modification of poorly dispersive polytetrafluoroethylene (PTFE) particles via bioinspired polydopamine–polyethyleneimine (PDA–PEI) which conferred PTFE particles a uniform dispersion in aqueous medium. With increasing dopamine concentration in the reaction solution, dispersity of PTFE particles improved and the surface charges of particles changed from negative to positive due to an increase of surface coverage of PDA–PEI layers. Simplicity of the method here outlines an attractive route for surface modification of inert surfaces useful for large-scale applications.

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