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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Crafting ordered structures of nanomaterials via flow-enabled self-assembly (FESA) and controlled evaporative self-assembly (CESA)

Li, Bo 08 June 2015 (has links)
The use of spontaneous self-assembly as a lithography free means to construct well-ordered, often intriguing structures has received much attention for its ease of producing complex, centimeter-scale structures with small feature sizes. These self-organized structures promise new opportunities for developing miniaturized optical, electronic, optoelectronic, and magnetic devices. One extremely simple route to intriguing structures is the evaporative self-assembly of nonvolatile solutes from a sessile droplet on a solid substrate. However, flow instabilities during the evaporation process often result in non-equilibrium and irregular dissipative structures (e.g., randomly organized convection patterns, stochastically distributed multi-rings, etc.). Therefore, in order to fully control the evaporative self-assembly of solutes, two strategies, namely, controlled evaporative self-assembly (CESA) and flow-enabled evaporative-induced self-assembly (FESA) were developed to create ordered structures of various nanomaterials. First, hierarchical assemblies of amphiphilic diblock copolymer (i.e., polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP)) micelles were crafted by FESA. The periodic threads comprising a monolayer or a bilayer of PS-b-P4VP micelles were precisely positioned and patterned over large areas. Second, highly aligned parallel DNA nanowires in the forms of nanostructured spokes over a macroscopic area were created via evaporative self-assembly (CESA) by subjecting DNA aqueous solution to evaporate in a curve-on-flat geometry composed of a spherical on a flat substrate. Third, large-scale aligned metallic nanowires templated by highly oriented DNA were produced by flow-enabled self-assembly (FESA). A simple yet robust swelling-induced transfer printing (SIT-Printing) technique was developed to transfer ultralong DNA nanowires onto the desirable substrate. Subsequently, the resulting DNA nanowires were exploited as templates to form metallic nanowires by exposing DNA nanowires preloaded with metal salts under oxygen plasma. Moreover, DNA nanowires were also employed as scaffold for aligning metal nanoparticles and nanorods. Fourth, colloidal microchannels (i.e., cracks) on a large scale were yielded by fully controlling the drying process of colloidal suspensions via flow-enabled self-assembly (FESA). The influence of chemically patterned substrate (i.e., hydrophobic stripes on a hydrophilic substrate) on the formation of colloidal microchannels was explored. In addition, such colloidal microchannels with tunable center-to-center distance between the adjacent cracks, λ_(c-c) was exploited as template for aligning inorganic nanoparticles. Importantly, theoretical study of the formation mechanism of parallel stripes of solutes by FESA was conducted. The relationship between the characteristic spacing of adjacent stripes λ_(c-c) and other experimental parameters such as the stripe width, the stop time and the moving speed of lower substrate were scrutinized. Such theoretical modeling would provide guidance for the precise design and crafting of ordered structures composed of nanomaterials by FESA in the future study. Interestingly, during the preparation of Au nanorods, the formation of ultrathin gold nanowires were unexpectedly observed. Based on conventional synthetic route to Au nanorods using CTAB as soft-templates, we discovered that the addition of a small amount of hydrophobic solvent (e.g., toluene or chloroform) to the Au growth solution entailed the formation of ultrathin Au nanowire, rather than Au nanorods. The growth mechanism of such intriguing water-soluble ultrathin Au nanowires, differed from those formed by using oleylamine (i.e., non-water-soluble Au nanowires), was explored. In general, the ability to craft ordered structures comprising nanomaterials by FESA and CESA provides new opportunities for organizing nanomaterials for use in electronics, optics, optoelectronics, sensors, nanotechnology and biotechnology.

Basics of Evaporation and Evapotranspiration

Brown, Paul 01 1900 (has links)
Revised. (Originally published: 2000). / 4 pp. / Introduction: Local information on evapotranspiration (ET) is now readily available from on-site weather stations and/or public weather networks to assist turfgrass professionals with irrigation management decisions. Proper utilization of ET information can provide accurate estimates of daily water use and thus can assist irrigation managers with the all important decisions of when to apply water and how much water to apply. The concept of ET can be confusing and often is presented in a highly technical manner. The objective of this and subsequent bulletins in the Turf Irrigation Management Series is to simplify the subject of ET and thereby increase the effective utilization of ET in irrigation management. This bulletin provides some basic background on the related subjects of evaporation and evapotranspiration.

Evapotranspiration of sprinkler irrigated cotton as related to meteorological factors

Konrad, Dwayne El Roy, 1933- January 1964 (has links)
No description available.

Evaluating selected methods for estimating reservoir evaporation in northeast Brazil

Matias Filho, Jose, 1927- January 1972 (has links)
No description available.

A study of evaporation from a short grass surface.

Kevan, Simon Michael January 1973 (has links)
No description available.

Factors contributing to evaporation over the North Atlantic.

Chisholm, William Joseph January 1966 (has links)
Mean evaporation patterns are presented for cyclones and for anticyclones. From these patterns it is deduced that the rate of evaporation is higher under cyclonic circulation than under anticyclonic circulation. The seasonal variation in the rate of evaporation is analyzed. [...]

An experimental investigation of the spreading, durability and maintainability of monolayer films for evaporation suppression from stationary watr pools

Pauken, Michael T. 05 1900 (has links)
No description available.

Comparisons of evaporation and evapotranspiration at Ebini

Fraser, Duncan. January 1974 (has links)
No description available.

An Experimental Test Facility for Studying the Effects of Turbulence on the Evaporation of Fuel Droplets at Elevated Pressure and Temperature Conditions

Fabbro, Sean 13 April 2012 (has links)
A test rig was developed in an effort to perform droplet evaporation and combustion experiments at high levels of turbulent intensity under elevated pressures and temperatures. The detailed explanation of the design and operation of the various components that are part of the testing apparatus is presented. Once the apparatus was completed, 2D Laser Doppler Velocimetry measurements were used to fully characterize the turbulent field inside the chamber. The results showed that the test rig was capable of producing homogenous isotropic turbulence with a 40 mm central region of the chamber at turbulent kinetic energy levels of up to 5.0 m/s. From the characterization data a correlation of turbulent kinetic energy vs fan speed was produced. The produced correlation is valid at standard conditions as well as elevated pressures and temperatures. After determination of the turbulent field, droplet evaporation experiments were performed, first at standard conditions and then elevated temperature and pressure. The results show that turbulence continued to enhance droplet evaporation at elevated temperature and pressures, 298-348°K and 1-21 bar respectively. Broad conclusions are then drawn from the work performed in the study and recommendations are made for future work and improvements to the test apparatus.

Measurements of the evaporation rates of heated liquid droplets

Crafton, Elyssa Farah 05 1900 (has links)
No description available.

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