V2V communication-enabled collision avoidance for railroad vehicles

Tato práce se zabývá návrhem systému pro predejití srážce tramvají s využitím V2V (vehicleto-vehicle) komunikace mezi tramvajemi. V2V komunikace spadá pod kategorii vyhrazené komunikace krátkého dosahu umožnující bezdrátovou komunikaci mezi vozidly. V práci je popsán návrh algoritmu, který by mohl bežet na palube tramvaje a v prípade hrozící srážky s tramvají jedoucí vpred upozornit ridice na nutnost neprodlené akce pro zabránení srážky. Jednou ze soucástí algoritmu je pozorovatel stavu systému založený na Kalmanovu filtru využívající k odhadu stavu systému merení z inerciálních senzoru a GNSS/GPS. Funkcnost navrženého algoritmu je následne rozsáhle otestována na simulacích s ruzným nastavením parametru algoritmu i simulace. K tomuto úcelu práce také predkládá odvození matematického modelu podélné dynamiky tramvaje spolecne s modelem ridice. Pomocí tohoto modelu lze generovat data verná reálným merením ze senzoru s prijatelnou presností.This thesis deals with the design of a collision avoidance system for trams utilizing V2V (vehicle-to-vehicle) communication between trams. V2V communication falls under the category of dedicated short-range communication technology, allowing to establish wireless communication between two vehicles. The thesis presents an algorithm which could run onboard a tram and in case of an imminent collision with tram ahead warn a driver that immediate action is required to prevent the collision. One part of the algorithm is an estimator of tram longitudinal motion based on Kalman filter which uses for estimation measurements from inertial sensors and GNSS/GPS. The functionality of this algorithm is then extensively tested using simulations with a different set of parameters of both the algorithm and simulations. For this purpose, the thesis also presents a mathematical model of longitudinal dynamics of a tram, including a model of a driver. The model generates data with acceptable accuracy close to real measurements

Evolution of strategies to prepare synthetic mimics of carboxylate-bridged diiron protein active sites

We present a comprehensive review of research conducted in our laboratory in pursuit of the long-term goal of reproducing the structures and reactivity of carboxylate-bridged diiron centers used in biology to activate dioxygen for the conversion of hydrocarbons to alcohols and related products. This article describes the evolution of strategies devised to achieve these goals and illustrates the challenges in getting there. Particular emphasis is placed on controlling the geometry and coordination environment of the diiron core, preventing formation of polynuclear iron clusters, maintaining the structural integrity of model complexes during reactions with dioxygen, and tuning the ligand framework to stabilize desired oxygenated diiron species. Studies of the various model systems have improved our understanding of the electronic and physical characteristics of carboxylate-bridged diiron units and their reactivity toward molecular oxygen and organic moieties. The principles and lessons that have emerged from these investigations will guide future efforts to develop more sophisticated diiron protein model complexes.National Institute of General Medical Sciences (U.S.

Controlled Synchronization of Coupled Pendulums by Koopman Model Predictive Control

We propose and experimentally demonstrate a feedback control method that allows synchronizing the motion of a chain of several coupled nonlinear oscillators actuated through one end of the chain. The chain considered in this work is a one-dimensional array of pendulums pivoting around a single axis and interacting with adjacent pendulums through torsion springs; the array is actuated using a single torque motor attached to one of the two boundary pendulums. This represents a mechanical realization of the Frenkel-Kontorova model { a spatially discrete version of a sine-Gordon equation describing (nonlinear) waves. The main challenges of controlling these systems are: high order (the number of pendulums can be high), nonlinear dynamics, and (as we set the problem here) only one actuator. The presented problem of synchronization of motion is a special case of the problem of reference tracking, where all pendulums reach a common point or a trajectory. In particular, we demonstrate synchronization to a stable equilibrium (all pendulums downward), unstable equilibrium (all pendulums upward), and a periodic orbit (all pendulums revolving). We use the Koopman Model Predictive Control (KMPC) that constructs a linear predictor of the nonlinear system in a higher-dimensional lifted space and uses the predictor within a classical linear MPC, thereby maintaining low computational cost that allows for a real-time implementation, while taking into account the complex nonlinear dynamics

Developing functional protein mimics through ligand design and understanding dioxygen activation

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2011.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Vita. Cataloged from student submitted PDF version of thesis.Includes bibliographical references.Chapter 1 A comprehensive review of diiron modeling in the Lippard group over the past thirty years is presented. This account describes the different strategies employed to prepare biomimetic complexes of non-heme diiron protein active sites, highlighting the accomplishments of the past as well as the challenges for the future. Studies of various model systems have led to a more profound understanding of the fundamental properties of carboxylate-bridged diiron units and their reactivity toward molecular oxygen and organic substrates. The key principles and lessons that have emerged from these studies have been an inspiration for the original work presented in this thesis. Chapter 2 A series of phenoxylpyridyl and phenoxylimine ligands, H2LR,R' (compounds derived from bis(phenoxylpyridyl)diethynylbenzene, where R = H, Me, or t-Bu, and R' = H, or Ph) and H2BIPSMe,Ph (bis((phenylphenoxyl)iminephenyl)sulfone) were synthesized as platforms for non-heme diiron(II) protein (III) core and molecular oxygen as the source of the bridging oxo group. The [LMe,Ph]2- ligand is robust toward oxidative decomposition and does not display any reversible redox activity. Chapter 3 A dinucleating macrocycle, H2PIM, containing phenoxylimine metal-binding units has been prepared. Reaction of H2PIM with [Fe2(Mes)4] (Mes = 2,4,6-trimethylphenyl) and sterically hindered carboxylic acids, Ph3CCO2H or ArTolCO2H (2,6-bis(p-tolyl)benzoic acid), afforded complexes [Fe2(PIM)(Ph3CCO2)2] (1) and [Fe2(PIM)(ArTolCO2)2] (2), respectively. X-ray diffraction studies revealed that these diiron(II) complexes closely mimic the active site structures of the hydroxylase components of bacterial multi-component monooxygenases (BMMs), particularly the syn disposition of the nitrogen donor atoms and the bridging [mu]--n1n2 and [mu]-n1n1 modes of the carboxylate ligands at the diiron(II) centers. Cyclic voltammograms of 1 and 2 displayed quasi-reversible redox couples at +16 and +108 mV vs. ferrocene/ferrocenium, respectively, assigned to metal-centered oxidations. Treatment of 2 with silver perchlorate afforded a silver(I)/diiron(III) heterotrimetallic complex, [Fe2([mu]-OH)2(CIO4)2(PIM)(ArTolCO2)Ag] (3), which was structurally and spectroscopically characterized. Complexes 1 and 2 both react rapidly with dioxygen. Oxygenation of 1 afforded a ([mu]-hydroxo)diiron(III) complex [Fe2([mu]- OH)(PIM)(Ph3CCO2)3] (4), a hexa([mu]-hydroxo)tetrairon(III) complex [Fe4([mu]- OH)6(PIM)2(Ph3CCO2)2] (5), and an unidentified iron(III) species. Oxygenation of 2 exclusively formed di(carboxylato)diiron(III) products. X-ray crystallographic and 57Fe Mössbauer spectroscopic investigations indicated that 2 reacts with dioxygen to give a mixture of ([mu]- oxo)diiron(III) [Fe2([mu]-O)(PIM)(ArTolCO2)2] (6) and di([mu]-hydroxo)diiron(III) [Fe2([mu]- OH)2(PIM)(ArTolCO2)2] (7) complexes in the same crystal lattice. Compounds 6 and 7 spontaneously convert to a tetrairon(III) complex, [Fe4([mu]-OH)6(PIM)2(ArTolCO2)2] (8), when treated with excess H2O. The possible biological implications of these findings are discussed. Chapter 4 To investigate how protons may be involved in the dioxygen activation pathway of non-heme diiron enzymes, the reaction of H+ with a synthetic ([mu]-1,2-peroxo)(carboxylato)diiron(III) complex was explored. Addition of an H+ donor to [Fe2(O2)(N-EtHPTB)(PhCO2)]2+ (1.O2, where N-EtHPTB = anion of N,N,N' ,N' -tetrakis(2-benzimidazolylmethyl)-2-hydroxy-1,3-diaminopropane) resulted in protonation of the carboxylate rather than the peroxo ligand. Mössbauer and resonance Raman spectroscopic measurements indicate that the Fe2(O2) core of the protonated complex [1.O2]H+ is identical to that of 1.O2. In contrast, the benzoate ligand of [1.O2]H+ displays significantly different IR and NMR spectral features relative to those of the starting complex. The [1.O2]H+ species can be converted back to 1.O2 upon treatment with base, indicating that protonation of the carboxylate is reversible. These findings suggest that in the reaction cycle of soluble methane monooxygenases and related diiron proteins, protons may 6 induce a carboxylate shift to enable substrate access to the diiron core and/or increase the electrophilicity of the oxygenated complex. Chapter 5 To explore additional methods to interrogate the properties of diiron protein intermediates, studies of the vibrational profiles of ([mu]-1,2-peroxo)diiron(III) species were pursued using nuclear resonance vibrational spectroscopy (NRVS). Comparison of the NRVS of [Fe2(O2)(NEtHPTB)(PhCO2)]2+ (1.O2) to that of the diiron(II) starting material [Fe2(N-EtHPTB)(PhCO2)]2+ (1) revealed that the oxygenated complex displays new frequencies above 350 cm-1, which are attributed to the Fe-O-O-Fe core vibrations based on 18O2/16O2 isotopic labeling studies. The peak at 338 cm-1 has not been previously observed by resonance Raman spectroscopy. Empirical normal mode analysis provides a qualitative description of these isotopic sensitive modes. The NRVS of [Fe2([mu]-O2)(HB(iPrpz)3)2(PhCH2CO2)2] (4.O2, where HB(iPrpz)3 = tris(3,5-diisopropylpyrazoyl) hydroborate) was also measured and shows several Fe2(O2) modes between 350-500 cm-1. Appendix A Attempts to prepare a diiron(IV) complex described in the literature led to several unexpected discoveries. Reaction of tris((3,5-dimethyl-4-methoxy)pyridyl-2-methyl)amine (R3TPA) with iron(III) perchlorate decahydrate and sodium hydroxide afforded a ([mu]-oxo)([mu]-hydroxo)diiron(III) [Fe2([mu]-O)([mu]-OH)(R3TPA)2](ClO4)3 complex (1), rather than [Fe2([mu]-O)(OH)(H2O)-(R3TPA)2](ClO4)3 (B) as previously reported. The putative diiron(III) starting material B is formed only at low temperature when excess water is present. Compound 1 hydrolyzes acetonitrile to acetate under ambient conditions. The acetate-bridged diiron compound, [Fe2([mu]- O)([mu]-CH3CO2)(R3TPA)2](ClO4)3 (4A), was characterized by X-ray crystallography as well as various spectroscopic methods and elemental analysis. The identity of the acetate bridged complex was confirmed by comparing the structural and spectroscopic characteristics of 4A to those of an independently prepared sample of [Fe2([mu]-O)([mu]-CH3CO2)(R3TPA)2](ClO4)3.by Loi Hung Do.Ph.D

Can the Higgs field feel a dark force?

We argue that if an electroweak Higgs field possesses a dark gauge charge responsible for dark matter stability, the $W$-boson mass deviation is properly induced, besides appropriately generated neutrino masses. We examine a simple model in which the usual Higgs doublet plays the role but dark matter candidates are somewhat input by ad hoc. We look for a realistic model that fully realizes such observation, thereby neutrino mass and dark matter are naturally supplied by a dark non-abelian gauge symmetry.Comment: 22 pages, 4 figures, 3 table

Light-Induced N₂O Production from a Non-Heme Iron–Nitrosyl Dimer

Two non-heme iron–nitrosyl species, [Fe₂(N-Et-HPTB)(O₂CPh)(NO)₂](BF4)₂(1a) and [Fe₂(N-Et-HPTB)(DMF)₂(NO)(OH)](BF₄)₃ (2a), are characterized by FTIR and resonance Raman spectroscopy. Binding of NO is reversible in both complexes, which are prone to NO photolysis under visible light illumination. Photoproduction of N₂O occurs in high yield for 1a but not 2a. Low-temperature FTIR photolysis experiments with 1a in acetonitrile do not reveal any intermediate species, but in THF at room temperature, a new {FeNO}⁷ species quickly forms under illumination and exhibits a ν(NO) vibration indicative of nitroxyl-like character. This metastable species reacts further under illumination to produce N₂O. A reaction mechanism is proposed, and implications for NO reduction in flavodiiron proteins are discussed.National Institutes of Health (U.S.) (GM074785)National Institutes of Health (U.S.) (GM032134

Characterization of a synthetic peroxodiiron(III) protein model complex by nuclear resonance vibrational spectroscopy

The vibrational spectrum of an η[superscript 1],η[superscript 1]-1,2-peroxodiiron(III) complex was measured by nuclear resonance vibrational spectroscopy and fit using an empirical force field analysis. Isotopic 18O2 labelling studies revealed a feature involving motion of the {Fe2(O2)}[superscript 4+] core that was not previously observed by resonance Raman spectroscopy.National Institute of General Medical Sciences (U.S.) (GM-032134