International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / Synthetic Aperture Radar (SAR) systems are typically very complex and expensive. They generate enormous quantities of data, requiring very high capacity data storage, transmission, and processing systems. We have developed an experimental SAR system with a very simple design which includes near-real-time onboard processing. This system is based on recent developments in low-cost, high-rate analog-to-digital (A/D) and digital-to-analog (D/A) data conversion systems. Most of the system is based on off-the-shelf components. A very simple RF subsystem is used. The system has been successfully operated from a moving surface vehicle and exhibits a range resolution of 2.5 m though this could be improved to 1.5 m at the expense of higher sidelobes. The four look azimuth resolution is 0.4 m. This paper describes the system as well as our plans for upgrading the system for aircraft operation and improved resolution.

M.Phil. (Energy Studies) / Liquid fuels provide in a large percentage of South Africa's energy requirements. Because of the vastness of the country no other means of propelling transport could take the place of liquid fuel. South Africa who has for a substantial period found herself being officially cut-off from international crude oil (embargo) and other commodities such as capital, had up to ± 1991 survive this onslaught. Alternatives for the substitution of crude oil derived products (mostly liquid fuels) has been under investigation for many years, internationally as well as locally~ Because of the recent change in the situation, the approach to new investment in this field will now only be effected should it be economically more attractive than investment in the traditional crude oil processes. This study was specifically aimed at, from a South African viewpoint, summarizing various applicable liquid fuel manufacturing processes and related raw material resources, and comparing these processes both from an economic and technological angle with that of crude oil refining. The following resources were investigated: Coal, torbanite, sugar (from sugar cane), natural gas and sunflower seeds. Processes such as coal to fuels (Fischer-Tropsch, coal hydrogenation, solvent extraction), metanol to fuels (MTG-process), metanol ex natural gas (Mobil-M), methanol ex coal, ethanol ex sugar, natural gas to fuels (Fischer-Tropsch, Shell-SMOS), esters (diesel) ex sunflower seeds, fuels ex torbanite via retorting were researched. Aspects covering the availability of resources, degree of commercialisation of processes, product quality and fuel/engine compatibility and general economic and technological guidelines were covered in the study.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg, 29 August 2016 / This study discusses underground coal gasification (UCG) and the analysis thereof. Two main methods were used. The first is the Bond Equivalent Diagram, which gives an ideal of where operations should take place in relation to their coal and product gas compositions. This method was used to analyze several real life sites for their idealized and actual operations. The second consisted of a comparative exergy simulation study. This was done for an air-blown UCG plant with a downstream Fischer-Tropsch reactor and an oxygen-blown UCG plant with upstream air separation. The plants were analyzed by their overall exergy efficiency as well as their exergy outputs with respect to coal inputs (fuel). It was discovered that the air-blown simulation with downstream Fischer-Tropsch was the better choice from an exergy point of view due to it having higher efficiencies (1.5 for overall, 1.38 for fuel) as opposed to the oxygen-blown simulation (0.77 overall, 0.8 for fuel). This coupled with other design and safety factors led to the conclusion that the air-blown simulation was better. / MT2017

Thesis. 1979. M.S.--Massachusetts Institute of Technology. Alfred P. Sloan School of Management. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND DEWEY. / Includes bibliographical references. / M.S.

I propose the use of the tandem fluorescent timer protein as a reporter of dynamic gene regulation. The tandem fluorescent timer is a fusion of two fluorophores with different maturation kinetics whose fluorescence ratio is a reporter of protein age. Traditional approaches to live single-cell tracking of dynamic gene expression involve the use of destabilized fluorescent reporters. The reduced stability of these reporters improve performance but also result in reduced signal and an increased signal to noise ratio. I first develop a platform to test reporter performance by designing and implementing an inducible synthetic network orthogonally in S. cerevisiae cells and by developing a microfluidics-enabled live cell-tracking pipeline. To test the performance of different reporters, I develop an algorithm to decode the underlying regulatory dynamic signal of a fluorescence profile. I then simulate the fluorescence output of my platform under dynamic regulatory signaling to demonstrate the potential reporter performance of a stable timer protein. Finally, I conduct live cell-tracking experiments of yeast cells expressing the timer under a periodic signal to test in vivo performance of the tandem fluorescent timer. I demonstrate that compared to a traditional stable fluorescent reporter, the tandem fluorescent timer is more accurate when tracking faster periodic signals and it is more robust to global fluctuations.

Typescript. Bibliography: p. 199-208.

The next generations of both biological engineering and computer engineering demand that control be exerted at the molecular level. Creating, characterizing and controlling synthetic biological systems may provide us with the ability to build cells that are capable of a plethora of activities, from computation to synthesizing nanostructures. To develop these systems, we must have a set of tools not only for synthesizing systems, but also designing and simulating them. The BioJADE project provides a comprehensive, extensible design and simulation platform for synthetic biology. BioJADE is a graphical design tool built in Java, utilizing a database back end, and supports a range of simulations using an XML communication protocol. BioJADE currently supports a library of over 100 parts with which it can compile designs into actual DNA, and then generate synthesis instructions to build the physical parts. The BioJADE project contributes several tools to Synthetic Biology. BioJADE in itself is a powerful tool for synthetic biology designers. Additionally, we developed and now make use of a centralized BioBricks repository, which enables the sharing of BioBrick components between researchers, and vastly reduces the barriers to entry for aspiring Synthetic Biologists.

This dissertation examines the Carnap-Quine debate on analyticity with the objective of identifying exactly what is at stake. Close scrutiny of Quine’s criticism of the definitions of analyticity reveals that most of his objections are convincing only if they are considered in relation to the definitions of analyticity in natural language. Carnap, however, defines analyticity in artificial languages. The dissertation also shows that Carnap can meet the objections to his definitions by using a perspective based within his own philosophy. After examining the presumptions of each party to the debate, the dissertation concludes that the disagreement between Carnap and Quine on the notion of analyticity is rooted in their different approaches to empiricism and that there is nothing said by either philosopher which proves that one approach has ultimate advantages over the other. It is thus impossible to identify a winner in the Carnap-Quine debate on analyticity. The process of arriving at this conclusion starts with a discussion in the first three chapters of Carnap’s philosophy followed by a critical and detailed discussion of his syntactical and semantical definitions of analyticity and the advantages and disadvantages of each. Chapter Four examines Quine’s objections to Carnap’s definitions of essential predication and shows that his objections do not undermine Carnap’s definitions of this notion in artificial languages. It also shows how vital providing a proper definition of essential predication in natural language is for Carnap’s philosophy and examines whether or not he is able to do so. Chapter Five analyzes Quine’s objections to Carnap’s definitions of logical truth and demonstrates that Carnap is able to respond to all of them when the discussion is situated within his philosophical system. Again, Quine’s objections to definitions of logical truth are meaningful only if they are considered in relation to natural language, which is not Carnap’s concern. The dissertation concludes by showing that both Carnap and Quine arrived at their conclusions with respect to the nature of logical sentences, based not on the arguments in their debate on analyticity, but on their philosophical considerations regarding the principle of empiricism: for Carnap, logical sentences are out of the realm of knowledge and independent of matters of fact whereas, for Quine, these are as empirical as other sentences. Nothing either says in their debate can convince the other to accept a different viewpoint.

The study of synthetic gene regulatory networks allows the isolation and investigation of components and motifs in natural regulatory networks. Many synthetic gene networks are regulated at the transcriptional level. In this work, two methods of regulating gene expression at the transcriptional level were studied with the objective of gaining finer control over network behaviour. The first approach focuses on activation and repression of promoters by transcription factors. A synthetic repressor-activator network was engineered using the cI and cro genes and the PRM promoter from bacteriophage λ. The cI and cro genes activated and repressed PRM, respectively, and the monomeric red fluorescent protein (mrfp) gene reported PRM activity. Experimental testing showed an increase in mrfp expression in response to CI, a decrease in mrfp expression in response to Cro, and a differential output that reflected the relative concentrations of CI and Cro when both inputs were applied together. A positive feedback network was then created by placing a cI gene downstream of PRM. The network showed increased expression in response to CI and decreased expression in response to Cro. A negative feedback network was created by placing a cro gene downstream of PRM. Experimental testing showed decreased mrfp expression in response to both inputs. The second approach employed two methods for tuning expression levels without modifying the genes or promoters. First, using a series of networks with tandem mrfp genes under the control of the PLtet0-1 promoter, it was demonstrated that magnitude and range of expression levels could be tuned by adjusting the number of genes in the operon. A network was tuned using this principle by placing luxR genes in tandem to increase the activity of the luxPR promoter. It was then demonstrated that the level of gene expression could be varied through the placement of the gene within an operon. Operons that were three, five and seven genes and contained one green fluorescent protein gene in the first, middle, or end position were created. By comparing green fluorescence levels in induced and uninduced networks, it was found that the gene closest to the promoter was the most inducible.

Chapter 1 details our investigation into the Diels-Alder reaction between arynes and chiral furans and pyrroles for the synthesis of unsymmetrical [2.2.1] oxabicyclic and azabicyclic scaffolds as single enantiomers. It was discovered that the diastereoselectivity of the aryne Diels-Alder reaction was sensitive to conformational effects that could be exploited to obtain both high yields and dr. Stereoselective synthesis using arynes is an overlooked field, and this contribution represents one of only three such examples in the literature. The desymmetrization of meso [2.2.1] oxabicyclic systems by intramolecular cyclization/ring- opening was studied, and a cationic Rh/t-Bu-Josiphos catalyst was developed that delivered polyclic dihydronaphthalene products in excellent yield and ee. These catalyst conditions were used for the ring-opening of an enantiomerically pure unsymmetrical oxabicyclic alkene, which led to the discovery that ring-opening proceeded with complete reagent control. A regiodivergent resolution was designed that gave pairs of enantiomerically enriched dihydronaphthalenes from unsymmetrical racemic starting materials. In chapter 3, the scope of the regiodivergent resolution was expanded to include the ring-opening of remotely-substituted oxabicyclic alkenes and furan-hetaryne Diels-Alder adducts. The utility ii of the method was demonstrated by using it to synthesize two important API molecules from a single racemic precursor. Finally, chapter 4 describes our lab’s efforts toward the total synthesis of the natural products phorbol and prostratin that features the ring-opening of an unsymmetrical [3.2.1] oxabicycle as the key step. Advanced intermediates (requiring >30 linear steps) were synthesized on gram- scale. The entire carbon framework was successfully installed, and our efforts to complete the synthesis are discussed.