Comparative Study of Anionic and Nonionic/Anionic Surfactant Systems in Micellar Electrokinetic Capillary Chromatography.

Micellar electrokinetic capillary chromatography (MECC) is a rapidly growing technique allowing separation of electrically neutral compounds with the high separation efficiencies typically observed in capillary zone electrophoresis. This technique is still in its infancy and subsequently suffers from several inherent problems which must be addressed such as the limited range of solute elution and clear protocol for optimization of separations. This work addresses these problems with primary emphasis on using mixed nonionic/anionic surfactant systems as opposed to pure surfactants. In Chapter One, the fundamental theory behind MECC is discussed along with a brief synopsis of previous studies involving different surfactant systems, modification of micellar media with organic solvents, and the effect of mobile phase variation on the solute elution range. Chapter Two addresses resolution optimization by adjusting surfactant concentration. Two surfactant systems, pure SDS and Brij 35/SDS, were used in this study. The Brij 35/SDS system was advantageous due to higher separation efficiency, more constant elution ranges \rm (t\sb{mc}/t\sb{o}), and resolution optimization between hydrophilic analytes; SDS found favor for optimizing the resolution between moderately hydrophobic solutes. Chapter Three is a more in-depth comparison of SDS and Brij 35/SDS surfactant systems. Results indicate that in the Brij 35/SDS system, solute/micellar surface interactions play a key role in retention of certain compounds. Also, changes in electroosmotic and micellar electrophoretic velocities with varying Brij 35 concentration indicate the possibility of an infinite elution range in this system. Chapters Four and Five discuss the effects of three organic modifiers; acetonitrile, methanol, and l-propanol; upon the retention characteristics of an n-alkylphenone homologous series for the SDS and Brij 35/SDS systems, respectively. Our results point to greater structural stability for Brij 35/SDS micelles. Also, the polyoxyethylene surface layer of Brij 35/SDS micelles may influence solute partitioning via reduced solute/micellar surface interactions. Finally, the appendix reports our work on the combination of secondary chemical equilibrium (SCE)-LC sequentially with reversed-phase HPLC to provide multimodal separation of complex samples on a single column

Benefits and Incentives for ADS-B Equipage in the National Airspace System

Automatic Dependent Surveillance – Broadcast (ADS-B) is a technology that can replace secondary surveillance radars and enhance cockpit situational awareness. It also has the potential to enable procedures not possible with current surveillance technology that would increase the capacity of the National Airspace System (NAS) in the US. Certain forms of ADS-B also have the bandwidth to upload weather and airspace information into the cockpit. However, prior to achieving the benefits of ADS-B, operators must equip with the technology. In order to voluntarily equip, owners and operators must receive benefits from the technology that outweigh the cost or receive other incentives. Through an online survey of stakeholders, applications of ADS-B with the strongest benefits to users are identified. In-cockpit data link offerings are explored in detail, along with a detailed analysis of ADS-B benefits for Hawaiian helicopter operators. The conclusions of this study are that ADS-B should be implemented in non-radar airspace along with busy terminal areas first to gain the most benefits from non-radar separation applications and traffic awareness applications. Also, the basis for the US dual ADS-B link decision is questioned, with a single 1090-ES based link augmented with satellite data link weather recommended.The authors would like to thank all of interview and survey participants. Without their time and insights, this thesis would not be possible. Also, thanks to the FAA’s Surveillance and Broadcast Services program office for their support of this research under contract DTFA01-C-00030

Introduction to the problem of rocket-powered aircraft performance

An introduction to the problem of determining the fundamental limitations on the performance possibilities of rocket-powered aircraft is presented. Previous material on the subject is reviewed and given in condensed form along with supplementary analyses. Some of the problems discussed are: 1) limiting velocity of a rocket projectile; 2) limiting velocity of a rocket jet; 3) jet efficiency; 4) nozzle characteristics; 5) maximum attainable altitudes; 6) ranges. Formulas are presented relating the performance of a rocket-powered aircraft to basic weight and nozzle dimensional parameters. The use of these formulas is illustrated by their application to the special case of a nonlifting rocket projectile

Towards scalable and controlled synthesis of metal–organic framework materials using continuous flow reactors

Metal–organic frameworks have emerged as one of the most diverse new families of materials in the past few years. Their hybrid structures, combinations of inorganic and organic moieties, give a wide range of complex architectures with resultant properties that are suitable for numerous important fields, including porosity for molecular sieving and sensing, heterogeneous catalysis, drug delivery, and energy storage. If applications of these materials are to be realised then scalable synthesis is required, taking laboratory batch reactions towards industrial production. Continuous flow reactors offer the most versatile method for scaling their solvothermal synthesis, with the largest range of materials accessible, in high yield, and with control over crystal form

The Dynamics of Air Transportation System Transition

Both U.S. and European Air Transportation Systems face substantial challenges in transforming to meet future demand. This paper uses a feedback model to identify and describe key issues in the dynamics of system transition, with particular emphasis on stakeholder cost-benefit dynamics and processes for reviewing and implementing new system capabilities. Understanding of these dynamics is further reinforced through discussion of ADS-B and new runway construction examples. To implement the significant changes currently envisioned for ATM systems, it will be critical to structure system changes to anticipate and overcome stakeholder disagreements and improve the efficiency of the approval and implementation processes

The characterisation of coals for combustion

The use of coal in the production of energy, will continue around the world into the next century, and onwards. From an environmental perspective, as well as a financial one, man has attempted to increase the efficiency of energy production from initial raw materials. Environmentally, the poor conversion of coal to energy means a waste of earth's resources, as well as the production of more waste. From a financial viewpoint, poor combustion means less energy per tonne of coal, hence less profit. Poor combustion will also mean higher levels of carbon in ash. Increased carbon levels will change the physical properties of the ash, and therefore reduce the possible number of outlets for its disposal. It is essential, from a coal buyer’s point of view that he makes an 'informed' choice, as to the type of coal he is buying, especially if coals in question are imported. There is sufficient evidence to suggest that most techniques that currently exist are unable to characterise world coals successfully. The reason for this has been linked to the unusual petrographic nature of various world coals. It seems logical therefore, that an analytical technique based on the petrography of a coal, would be capable of providing a better characteristic assessment of any given coal type. The use of image analysis in providing petrographic information has been investigated, along with several different techniques for the characterisation of char and coal particles. Char production itself has been studied, mainly concerned with the production of representative char samples. A range of different operating conditions were used, including temperature ranges of 1000°C to 1400°C, oxygen contents of 0 to 3 %, and residence times of 100 to 200 milliseconds. From the experiments carried out, it was possible to correlate char structure to the initial coal using a reflectance/fluorescence program, specially designed for the measurement of a coals 'reactivity'. Other prediction systems, such Rank, Fuel Ratio and Reactive Macerals did not correlate as well to the combustion products from the Drop Tube Furnace

Large-scale continuous hydrothermal production and activation of ZIF-8

A new method for the large-scale hydrothermal production and activation of ZIF-8 is presented in this communication. Activated ZIF-8 has been produced, at lab-scale and pilot-scale, at a rate of 27 g h-1 and 810 g h-1 respectively with the activated material showing a surface area of 1800 m2 g-1