Decomposition studies of group 6 hexacarbonyl complexes. Part 1: Production and decomposition of Mo(CO)6 and W(CO)6

Chemical studies of superheavy elements require fast and efficient techniques, due to short half-lives and low production rates of the investigated nuclides. Here, we advocate for using a tubular flow reactor for assessing the thermal stability of the Sg carbonyl complex – Sg(CO)6. The experimental setup was tested with Mo and W carbonyl complexes, as their properties are established and supported by theoretical predictions. The suggested approach proved to be effective in discriminating between the thermal stabilities of Mo(CO)6 and W(CO)6. Therefore, an experimental verification of the predicted Sg–CO bond dissociation energy seems to be feasible by applying this technique. By investigating the effect of 104,105Mo beta-decay on the formation of 104,105Tc carbonyl complex, we estimated the lower reaction time limit for the metal carbonyl synthesis in the gas phase to be more than 100 ms. We examined further the influence of the wall material of the recoil chamber, the carrier gas composition, the gas flow rate, and the pressure on the production yield of 104Mo(CO)6, so that the future stability tests with Sg(CO)6 can be optimized accordingly.

Desarrollo de Técnicas Interferométricas para Radares de Alta Resolución en Milimétricas

En esta tesis doctoral se aborda el desarrollo de técnicas interferométricas para radares de alta resolución en milimétricas. Específicamente, se centra en el desarrollo de técnicas para radares terrestres y en concreto aquellas relacionadas con el seguimiento, clasificación y generación de imágenes de blancos móviles. Aparte del desarrollo teórico y simulación de las diferentes técnicas, uno de los grandes retos de esta tesis es la verificación experimental de las mismas. Para este propósito, se empleará un prototipo de sensor radar interferométrico de muy alta resolución y de ondas milimétricas. El primer capítulo de la tesis realiza una pequeña introducción a las técnicas interferométricas y presenta los objetivos, motivación y organización del presente trabajo. El segundo capítulo hace una pequeña introducción a los radares interferométricos de alta resolución en milimétricas y presenta el sensor radar experimental con el que se llevarán a cabo la validación de las distintas técnicas presentadas. El tercer capítulo recoge las distintas técnicas interferométricas desarrolladas para el seguimiento y cálculo de la altura de blancos móviles en radares de alta resolución. Entre ellas se encuentran: el seguimiento de blancos móviles en sucesión de imágenes ISAR, el cálculo de altura de blancos en imágenes radar bidimensionales distancia-tiempo y su equivalente en imágenes distancia-Doppler. El cuarto capítulo presenta una aplicación de las técnicas interferométricas para la vigilancia de tráfico en carreteras. Se describirán dos configuraciones radar que permiten calcular la velocidad de todos los blancos iluminados por el radar identificando de manera unívoca a los blancos en función del carril por el que circulen. El quinto capítulo presenta técnicas interferométricas aplicadas a la vigilancia en entornos marítimos basadas en la generación de imágenes interferométricas. Para demostrar la viabilidad del uso de estas imágenes se ha desarrollado un simulador de blancos móviles extensos realistas. Abstract This Ph. D thesis deals with the development of radar interferometry techniques for high-resolution millimeter wave sensors. It focuses on the development of techniques for ground-based radars and specifically those related to monitoring, classification and imaging of moving targets. Apart from the theoretical development and simulation, another major technical challenge of this thesis is the experimental verification of the different techniques. For that purpuse, a very high resolution interferometric millimeter wave radar sensor is used. The first chapter of the thesis makes a brief introduction to the interferometric techniques and shows the goals, motivation and organization of this work. The second chapter provides a brief introduction to high resolution interferometric radars in millimeter waves and presents the experimental radar sensor which will be used for the validation of the various techniques presented. The third chapter presents the different interferometric techniques developed for monitoring and obtaining the height of moving targets in high resolution radars. Among them are: tracking of moving targets in a succession of ISAR images, targets height calculation using bidimensional range-time radar images and the equivalente technique using range-Doppler images. The fourth chapter presents the application of interferometric techniques for road traffic monitoring. Two radar configurations are described. Both of them are able to obtain the speed for simultaneuslly illuminated targets, and univocally identify each target based on the detected road lane. The fifth chapter presents the application of interferometric techniques to maritime surveillance based on interferometric imaging. To demonstrate the feasibility of the presented techniques a realistic simulator of extended moving targets has been developed.

Optical Multistability and Oscillations in Hybrid Optical Bistable Systems with Short Delay Times

Optical instabilities in the output light from a bistable optical device (BOD) with a delayed feedback was predicted by Ikeda [1]. Gibbs et al. [2] gave the first experimental verification of this type of instabilities. From that time several groups have studied the instabilities of the BOD for different relations between the delay time tR and the time constant ح of the system. In a previous paper [3] an empirical and analytical study of instabilities in hybrid BOD was reported by us. The employed set up is shown in Fig. 1.

Evaluation of damping properties of structural glass panes under impact loading

The latest technology and architectural trends have significantly improved the use of a large variety of glass products in construction which, in function of their own characteristocs, allow to design and calculate structural glass elements under safety conditions. This paper presents the evaluation and analysis of the damping properties of rectangular laminated glass plates of 1.938 m x 0.876 m with different thickness depending on the number of PVB interlayers arranged. By means of numerical simulation and experimental verification, using modal analysis, natural frequencies and damping of the glass plates were calculated, both under free boundary conditions and operational conditions for the impact test equipment used in the experimental program, as the European standard UNE-EN 12600:2003 specifies.

Four primordial modes of tRNA-synthetase recognition, determined by the (G,C) operational code

In distinction to single-stranded anticodons built of G, C, A, and U bases, their presumable double-stranded precursors at the first three positions of the acceptor stem are composed almost invariably of G-C and C-G base pairs. Thus, the “second” operational RNA code responsible for correct aminoacylation seems to be a (G,C) code preceding the classic genetic code. Although historically rooted, the two codes were destined to diverge quite early. However, closer inspection revealed that two complementary catalytic domains of class I and class II aminoacyl-tRNA synthetases (aaRSs) multiplied by two, also complementary, G2-C71 and C2-G71 targets in tRNA acceptors, yield four (2 × 2) different modes of recognition. It appears therefore that the core four-column organization of the genetic code, associated with the most conservative central base of anticodons and codons, was in essence predetermined by these four recognition modes of the (G,C) operational code. The general conclusion follows that the genetic code per se looks like a “frozen accident” but only beyond the “2 × 2 = 4” scope. The four primordial modes of tRNA–aaRS recognition are amenable to direct experimental verification.

Gas-phase nitronium ion affinities.

Evaluation of nitronium ion-transfer equilibria, L1NO2+ + L2 = L2NO2+ + L1 (where L1 and L2 are ligands 1 and 2, respectively) by Fourier-transform ion cyclotron resonance mass spectrometry and application of the kinetic method, based on the metastable fragmentation of L1(NO2+)L2 nitronium ion-bound dimers led to a scale of relative gas-phase nitronium ion affinities. This scale, calibrated to a recent literature value for the NO2+ affinity of water, led for 18 ligands, including methanol, ammonia, representative ketones, nitriles, and nitroalkanes, to absolute NO2+ affinities, that fit a reasonably linear general correlation when plotted vs. the corresponding proton affinities (PAs). The slope of the plot depends to a certain extent on the specific nature of the ligands and, hence, the correlations between the NO2+ affinities, and the PAs of a given class of compounds display a better linearity than the general correlation and may afford a useful tool for predicting the NO2+ affinity of a molecule based on its PA. The NO2+ binding energies are considerably lower than the corresponding PAs and well below the binding energies of related polyatomic cations, such as NO+, a trend consistent with the available theoretical results on the structure and the stability of simple NO2+ complexes. The present study reports an example of extension of the kinetic method to dimers, such as L1(NO2+)L2, bound by polyatomic ions, which may considerably widen its scope. Finally, measurement of the NO2+ affinity of ammonia allowed evaluation of the otherwise inaccessible PA of the amino group of nitramide and, hence, direct experimental verification of previous theoretical estimates.

A Comprehensive Discussion of HMBC Pulse Sequences: 4. Establishing Two-Bond Correlations from HMBC and Related Experiments

The utility of the HMBC experiment for structure elucidation is unquestionable, but the nature of the coupling pathways leading to correlations in an HMBC experiment creates the potential for misinterpretation. This misinterpretation potential is intimately linked to the size of the long-range heteronuclear couplings involved, and may become troublesome in those cases of a particularly strong 2JCH correlation that might be mistaken for a 3JCH correlation or a 4JCH correlation of appreciable strength that could be mistaken for a weaker 3JCH correlation. To address these potential avenues of confusion, work from several laboratories has been focused on the development of what might be considered “coupling pathway edited” long-range heteronuclear correlation experiments that are derived from or related to the HMBC experiment. The first example of an effort to address the problems associated with correlation path length was seen in the heteronucleus-detected XCORFE experiment described by Reynolds and co-workers that predated the development of the HMBC experiment. Proton-detected analogs of the HMBC experiment intended to differentiate 2JCH correlations from nJCH correlations where n = 3, 4, include the 2J,3J-HMBC, HMBC-RELAY, H2BC, edited-HMBC, and HAT H2BC experiments. The principles underlying the critical components of each of these experiments are discussed and experimental verification of the results that can be obtained using model compounds are shown. This contribution concludes with a brief discussion of the 1,1-ADEQUATE experiments that provide an alternative means of identifying adjacent protonated and non-protonated carbon correlations by exploiting 1JCC correlations at natural abundance.

A planar microwave imaging system with step-frequency synthesized pulse using different calibration methods

An experimental study of a planar microwave imaging system with step-frequency synthesized pulse for possible use in medical applications is described. Simple phantoms, consisting of a cylindrical plastic container with air or oil imitating fatty tissues and small highly reflective objects emulating tumors, are scanned with a probe antenna over a planar surface in the X-band. Different calibration schemes are considered for successful detection of these objects. (c) 2006 Wiley Periodicals, Inc.

Measurement and modelling of controlled beach groundwater levels under wave action

New laboratory scale experimental data are presented on the forcing of beach groundwater levels by wave run-up. The experimental setup simulates a coastal barrier dividing the ocean from a relatively constant back beach water level, conditions approximating a closed off lagoon system or beach aquifer. The data are critically compared to an advanced numerical model for simulating wave and beach groundwater interaction in the coastal zone, and provide the first experimental verification of such a model. Overall model-data comparisons are good, but some systematic discrepancies are apparent, and reasons for these are discussed.

An analysis of the effect of process parameters on the formability of sheet metal

This investigation is in two parts, theory and experimental verification. (1) Theoretical Study In this study it is, for obvious reasons, necessary to analyse the concept of formability first. For the purpose of the present investigation it is sufficient to define the four aspects of formability as follows: (a) the formability of the material at a critical section, (b) the formability of the material in general, (c) process efficiency, (d) proportional increase in surface area. A method of quantitative assessment is proposed for each of the four aspects of formability. The theoretical study also includes the distinction between coaxial and non-coaxial strains which occur, respectively, in axisymmetrical and unsymmetrical forming processes and the inadequacy of the circular grid system for the assessment of formability is explained in the light of this distinction. (2) Experimental Study As one of the bases of the experimental work, the determination of the end point of a forming process, which sets the limit to the formability of the work material, is discussed. The effects of three process parameters on draw-in are shown graphically. Then the delay of fracture in sheet metal forming resulting from draw-in is analysed in kinematical terms, namely, through the radial displacements, the radial and the circumferential strains, and the projected thickness of the workpiece. Through the equilibrium equation of the membrane stresses, the effect on the shape of the unsupported region of the workpiece, and hence the position of the critical section is explained. Then, the effect of draw-in on the four aspects of formability is discussed throughout this investigation. The triangular coordinate system is used to present and analyse the triaxial strains involved. This coordinate system has the advantage of showing all the three principal strains in a material simultaneously, as well as representing clearly the many types of strains involved in sheet metal work.

Evolutionary Technique of Shorter Route Determination of Fire Brigade Following to Fire Place with the Optimized Space of Search

In this paper the technique of shorter route determination of fire engine to the fire place on time minimization criterion with the use of evolutionary modeling is offered. The algorithm of its realization on the base of complete and optimized space of search of possible decisions is explored. The aspects of goal function forming and program realization of method having a special purpose are considered. Experimental verification is executed and the results of comparative analysis with the expert conclusions are considered.

Advanced tilted fiber gratings and their applications

This thesis presents a detailed numerical analysis, fabrication method and experimental investigation on 45º tilted fiber gratings (45º-TFGs) and excessively tilted fiber gratings (Ex-TFGs), and their applications in fiber laser and sensing systems. The one of the most significant contributions of the work reported in this thesis is that the 45º-TFGs with high polarization extinction ratio (PER) have been fabricated in single mode telecom and polarization maintaining (PM) fibers with spectral response covering three prominent optic communication and central wavelength ranges at 1060nm, 1310nm and 1550nm. The most achieved PERs for the 45º-TFGs are up to and greater than 35-50dB, which have reached and even exceeded many commercial in-fiber polarizers. It has been proposed that the 45º-TFGs of high PER can be used as ideal in-fiber polarizers for a wide range of fiber systems and applications. In addition, in-depth detailed theoretical models and analysis have been developed and systematic experimental evaluation has been conducted producing results in excellent agreement with theoretical modeling. Another important outcome of the research work is the proposal and demonstration of all fiber Lyot filters (AFLFs) implemented by utilizing two (for a single stage type) and more (for multi-stage) 45º-TFGs in PM fiber cavity structure. The detailed theoretical analysis and modelling of such AFLFs have also been carried out giving design guidance for the practical implementation. The unique function advantages of 45º-TFG based AFLFs have been revealed, showing high finesse multi-wavelength transmission of single polarization and wide range of tuneability. The temperature tuning results of AFLFs have shown that the AFLFs have 60 times higher thermal sensitivity than the normal FBGs, thus permitting thermal tuning rate of ~8nm/10ºC. By using an intra-cavity AFLF, an all fiber soliton mode locking laser with almost total suppression of siliton sidebands, single polarization output and single/multi-wavelength switchable operation has been demonstrated. The final significant contribution is the theoretical analysis and experimental verification on the design, fabrication and sensing application of Ex-TFGs. The Ex-TFG sensitivity model to the surrounding medium refractive index (SRI) has been developed for the first time, and the factors that affect the thermal and SRI sensitivity in relation to the wavelength range, tilt angle, and the size of cladding have been investigated. As a practical SRI sensor, an 81º-TFG UV-inscribed in the fiber with small (40μm) cladding radius has shown an SRI sensitivity up to 1180nm/RIU in the index of 1.345 range. Finally, to ensure single polarization detection in such an SRI sensor, a hybrid configuration by UV-inscribing a 45º-TFG and an 81º-TFG closely on the same piece of fiber has been demonstrated as a more advanced SRI sensing system.

Analysis and design of power management scheme for an on-board solar energy storage system

This paper investigates the power management issues in a mobile solar energy storage system. A multi-converter based energy storage system is proposed, in which solar power is the primary source while the grid or the diesel generator is selected as the secondary source. The existence of the secondary source facilitates the battery state of charge detection by providing a constant battery charging current. Converter modeling, multi-converter control system design, digital implementation and experimental verification are introduced and discussed in details. The prototype experiment indicates that the converter system can provide a constant charging current during solar converter maximum power tracking operation, especially during large solar power output variation, which proves the feasibility of the proposed design. © 2014 IEEE.

Three-port DC-DC converter for stand-alone photovoltaic systems

System efficiency and cost effectiveness are of critical importance for photovoltaic (PV) systems. This paper addresses the two issues by developing a novel three-port dc-dc converter for stand-alone PV systems, based on an improved Flyback-Forward topology. It provides a compact single-unit solution with a combined feature of optimized maximum power point tracking (MPPT), high step-up ratio, galvanic isolation, and multiple operating modes for domestic and aerospace applications. A theoretical analysis is conducted to analyze the operating modes followed by simulation and experimental work. This paper is focused on a comprehensive modulation strategy utilizing both PWM and phase-shifted control that satisfies the requirement of PV power systems to achieve MPPT and output voltage regulation. A 250-W converter was designed and prototyped to provide experimental verification in term of system integration and high conversion efficiency.

Constant V/Hz control based on DSP for open winding doubly-fed wind power generator

A DSP implementation of Space Vector PWM (SVPWM) using constant V/Hz control for the open winding doubly-fed generator is proposed. This control of SVPWM modulation mode and open winding structure combination has the high voltage utilization ratio, greatly improves the control precision of the system, and reduces the stator winding output current distortion rate, though the complexity of the system is increased. This paper describes the basic principle of SVPWM and discusses the particularity of SVPWM waveform generated by hybrid vector under the condition of open winding. This method is applied to a state of doubly-fed wind power generator. The experimental verification shows that this control method can make the output voltage amplitude of the doubly-fed induction generator be 380V and the frequency be 50Hz by using of TMS32028335 chip based on constant V/Hz control of symmetric SVPWM modulation wave.