The implementation and applications of multiple-valued logic

Multiple-Valued Logic (MVL) takes two major forms. Multiple-valued circuits can implement the logic directly by using multiple-valued signals, or the logic can be implemented indirectly with binary circuits, by using more than one binary signal to represent a single multiple-valued signal. Techniques such as carry-save addition can be viewed as indirectly implemented MVL. Both direct and indirect techniques have been shown in the past to provide advantages over conventional arithmetic and logic techniques in algorithms required widely in computing for applications such as image and signal processing. It is possible to implement basic MVL building blocks at the transistor level. However, these circuits are difficult to design due to their non binary nature. In the design stage they are more like analogue circuits than binary circuits. Current integrated circuit technologies are biased towards binary circuitry. However, in spite of this, there is potential for power and area savings from MVL circuits, especially in technologies such as BiCMOS. This thesis shows that the use of voltage mode MVL will, in general not provide bandwidth increases on circuit buses because the buses become slower as the number of signal levels increases. Current mode MVL circuits however do have potential to reduce power and area requirements of arithmetic circuitry. The design of transistor level circuits is investigated in terms of a modern production technology. A novel methodology for the design of current mode MVL circuits is developed. The methodology is based upon the novel concept of the use of non-linear current encoding of signals, providing the opportunity for the efficient design of many previously unimplemented circuits in current mode MVL. This methodology is used to design a useful set of basic MVL building blocks, and fabrication results are reported. The creation of libraries of MVL circuits is also discussed. The CORDIC algorithm for two dimensional vector rotation is examined in detail as an example for indirect MVL implementation. The algorithm is extended to a set of three dimensional vector rotators using conventional arithmetic, redundant radix four arithmetic, and Taylor's series expansions. These algorithms can be used for two dimensional vector rotations in which no scale factor corrections are needed. The new algorithms are compared in terms of basic VLSI criteria against previously reported algorithms. A pipelined version of the redundant arithmetic algorithm is floorplanned and partially laid out to give indications of wiring overheads, and layout densities. An indirectly implemented MVL algorithm such as the CORDIC algorithm described in this thesis would clearly benefit from direct implementation in MVL

Understanding Metal-Metal Bonds in Heterobimetallic Complexes and Their Use as Catalysts for Dinitrogen Conversion

University of Minnesota Ph.D. dissertation. June 2016. Major: Chemistry. Advisor: Connie Lu. 1 computer file (PDF); xvii, 206 pages.The purpose of this thesis is to describe the synthesis and characterization of heterobimetallic complexes using the mixed amide-phosphine binucleating ligand, N(o-(NHCH2P(iPr)2)C6H4)3, that feature metal-metal bonds while exploiting the ability to change the supporting metal to tune the catalytic ability of an active Co center in the activation and reduction of dinitrogen. General characterization of heterobimetallic complexes include solid state structure, cyclic voltammetry, electronic ground state determination (EPR spectroscopy or SQUID magnetometry), NMR, Mössbauer, and UV-vis-NIR spectroscopies in combination with multi-configurational CAS calculations in collaboration with the Gagliardi group

Controller Design and Optimization for Rotor System Supported by Active Magnetic Bearings

Active Magnetic Bearings (AMBs) have been receiving increased attention in industry because of the advantages (contact-free, oil-free, etc.,) that they display in comparison with conventional bearings. They are used extensively in rotor system applications, especially in conditions where conventional bearing systems fail. Most AMBs are controlled by Proportional-Integral-Derivative (PID)-controllers. Controller design for AMB systems by means of hand tuning is time-consuming and requires expert knowledge. In order to avoid this situation and reduce the effort to tune the controller, multi-objective optimization with genetic algorithm is introduced to design and optimize the AMB controllers. In the optimization, criteria both in time and frequency domain are considered. A hierarchical fitness function evaluation procedure is used to accelerate the optimization process and to increase the probability of convergence. This evaluation procedure guides the optimizer to locate the small feasible region resulting mainly from the requirement for stability of control system. Another strategy to reduce the number of optimization parameters is developed, which is based on a sensitivity analysis of the controller parameters. This strategy reduces directly the complexity of the optimization problem and accelerates the optimization process. Controller designs for two AMB systems are considered in this thesis. Based on the introduced and presented hierarchical evaluation strategy, the controller design for the first AMB system is obtained without specific requirements related to initial solutions. The optimal controller design is applied to a test rig with a flexible rotor supported by AMBs. The results show that the introduced optimization procedure realizes the desired results of the controlled system’s behavior. The maximal speed of 15000 rpm is reached. The second AMB system is designed for a turbo-compressor. The introduced parameter reduction strategy is applied for the controller design of this AMB system. The controller design is optimized in the search space around an initial solution. Optimization results show the efficiency of the introduced strategy.Aufgrund vieler Vorteile (wie z. B. Kontaktfreiheit, Ölfreiheit) gegenüber konventionellen Lagern etablieren sich aktive Magnetlager zunehmend in der Industrie. Aktive Magnetlager werden zum großen Teil in Rotorsystemen verwendet, wo konventionelle Öllager für die Anwendung versagen. PID-Regler werden häufig für Magnetlager verwendet. Die Auslegung des Reglers wird durch manuelle Einstellung (trial and error) bestimmt und ist sehr zeitaufwendig. Zudem bedarf es spezieller Fachkenntnisse zur Einstellung. Um diese Situation zu vermeiden und den Aufwand für die Reglerauslegung zu reduzieren, wird die Mehrzieloptimierung mit Genetischen Algorithmen in der vorliegenden Arbeit zur Optimierung des Reglerentwurfs eingesetzt. In der Optimierung werden die Zielfunktionen sowohl im Zeit- wie auch im Frequenzbereich definiert. Um den Optimierungsprozess zu beschleunigen und die Wahrscheinlichkeit der Konvergenz der Optimierung zu erhöhen, wird eine hierarchische Struktur zur Bewertung der Zielfunktionen eingeführt. Dies hilft dem Optimierer bei der Lokalisierung des kleinen zulässigen Bereichs, der im Wesentlichen aus der Anforderung an die Stabilität des Magnetlagersystems resultiert. Desweitern wird eine Strategie zur Reduzierung der Optimierungsparameter entwickelt, die auf der Sensitivitätsanalyse der Reglerparameter basiert. Diese Strategie reduziert die Komplexität des Optimierungsproblems und führt zu einer Beschleunigung des Optimierungsprozesses. In der vorliegenden Arbeit wird der Reglerentwurf von zwei Magnetlagersystemen berücksichtigt. Mit Hilfe der eingeführten Strategie zur Bewertung der Zielfunktionen, werden die Reglerparameter von dem ersten Magnetlagersystem bestimmt bzw. optimiert, ohne dass irgendeine Information über die Anfangslösung erforderlich ist. Der optimale Reglerentwurf wird dann in einem Versuchstand implementiert, in dem eine elastische Welle durch zwei Magnetlager gelagert ist. Die Versuchsergebnisse zeigen, dass das gewünschte dynamische Verhalten des geregelten Magnetlagersystems durch die Optimierung erzielt wird. Die maximal zulässige Drehzahl (15000 rpm) des Versuchsstandes wird mit dem optimalen Regler ohne Probleme erreicht. Als zweites Beispiel wird der Reglerentwurf eines magnetgelagerten Rotorsystems eines Turboverdichters betrachtet. In der Reglerauslegung wird die vorgeschlagene Optimierungsstrategie mit Hilfe von Parameterreduktion verwendet. Die optimale Lösung wird lokal in der Nähe einer Anfangslösung gesucht. Die Optimierungsergebnisse zeigen die Effizienz der Optimierungsstrategie

Anti‐Tetanus Toxin Chelating Recombinant Antibodies by Phage Display

Chelating Recombinant Antibodies (CRAbs) are a form of high affinity tandem single chain antibody (scFv) with two component scFvs which target non‐overlapping epitopes on the same antigen molecule. The optimised inter‐scFv linker allows simultaneous engagement of the scFvs resulting in a synergistic improvement in affinity. High affinity is a desirable characteristic in therapeutic antibodies since it strongly correlates with improved potency. Building upon previous work, this thesis describes the development of a phage‐display based approach toward isolating CRAbs with both the optimal scFv pairing and inter‐scFv linker using tetanus toxin as a model antigen. This would circumvent the need for structural data and complement the traditional approaches used to enhance antibody affinity. Fifteen scFvs specific for the C‐terminal sub‐domain of the tetanus toxin heavy chain (TT‐Hc) were characterised in terms of overall and soluble expression levels, sequence and bioinformatics features, phage‐display propensity and toxin neutralisation potency. Seven clones were identified for further analysis by affinity measurements, oligomerisation analysis and quantitative toxin neutralisation capacity. These characteristics varied significantly between clones including the affinity (KD) which varied, from 10nM to over 1000nM. ScFv characterisation revealed a strong positive correlation between phage display propensity and overall expression levels as well as a strong correlation between clone affinity and potency. Multiple scFv pairings hypothetically capable of chelation were identified by competition binding analysis and many of these clones exhibited cooperative binding effects when added in combination to TT‐Hc. A tandem‐scFv library was constructed linking seven of the characterised scFv clones (C1, C2, C4, J2, J4, N4 and N5) in all 49 possible combinations and permutations each with 7 inter‐scFv linker lengths. The inter‐scFv linkers harboured some randomised codons giving a total diversity of 5x107 clones. The library contained a mixture of hypothetically chelating and competing scFv pairings. Carefully optimised affinity driven phage display which included off‐rate selection enriched the anti‐TT‐Hc tandem‐scFv library to up to 90% chelating clones from under 50% after just two‐rounds of selection with a single clone, C4‐N4, dominating around 30% of the output. This clone was classified as hypothetically chelating from the scFv competition binding experiments. Despite some modest biases in the constructed library, the results clearly indicated that phage display can enrich for an optimal and chelating scFv pairing. This approach for isolating CRAbs will allow for the facile isolation of very high affinity antibodies against any target of interest given a sufficiently diverse panel of scFvs circumventing the need for prior scFv characterisation or elucidation of antibody‐antigen structural data

Advanced Photonic Sciences

The new emerging field of photonics has significantly attracted the interest of many societies, professionals and researchers around the world. The great importance of this field is due to its applicability and possible utilization in almost all scientific and industrial areas. This book presents some advanced research topics in photonics. It consists of 16 chapters organized into three sections: Integrated Photonics, Photonic Materials and Photonic Applications. It can be said that this book is a good contribution for paving the way for further innovations in photonic technology. The chapters have been written and reviewed by well-experienced researchers in their fields. In their contributions they demonstrated the most profound knowledge and expertise for interested individuals in this expanding field. The book will be a good reference for experienced professionals, academics and researchers as well as young researchers only starting their carrier in this field