Perturbation Theory and Control in Classical or Quantum Mechanics by an Inversion Formula

We consider a perturbation of an ``integrable'' Hamiltonian and give an expression for the canonical or unitary transformation which ``simplifies'' this perturbed system. The problem is to invert a functional defined on the Lie- algebra of observables. We give a bound for the perturbation in order to solve this inversion. And apply this result to a particular case of the control theory, as a first example, and to the ``quantum adiabatic transformation'', as another example.Comment: Version 8.0. 26 pages, Latex2e, final version published in J. Phys.

Behaviour of large scale structures of the electron content as a key parameterfor range errors in GNSS applications

The Total Electron Content (TEC) of the ionosphere is a key parameter for describing the ionospheric state. This paper deals with the large scale behaviour of TEC under low and high solar activity conditions. Large scale structures of the plasma density are formed by fundamental ionospheric processes mainly driven by solar radiation input, neutral winds and electric fields. The monitoring of large scale structures contributes to a comprehensive understanding of these coupling mechanisms which are rather complex particularly under perturbed geomagnetic conditions. The paper addresses techniques to monitor TEC with sufficient accuracy of a few TEC units (1016m-2) to measure large scale structures over Europe and over the polar areas. The availability of GPS data from global GPS receiver networks as e.g., those from the International GPS Service (IGS) is dense enough to generate TEC maps on a continuous base. A model assisted technique is briefly described for mapping TEC over the European and polar areas. A statistical estimation of horizontal TEC gradients reveals large scale gradients of up to about 6 TECU/1000 km under high solar activity conditions at an occurrence probability level of about 1%. Occasionally, during severe ionospheric storms this value may increase by a factor of 10 or even more. A close correlation of large scale gradients and the geomagnetic activity has been found giving the chance to forecast TEC gradient amplitudes by using predicted geomagnetic indices. Since TEC is proportional to first-order range errors in Global Satellite Navigation Systems (GNSS) such as the US GPS and the Russian GLONASS the study of the behaviour of this parameter has a practical meaning in GNSS based navigation and positioning. The paper addresses the close relationship between TEC and ranging errors in GNSS. Having in view Galileo, the planned Europe’s own global satellite navigation system, some aspects related to the mitigation of ionospheric propagation errors within the European Geostationary Navigation Overlay System (EGNOS) are discussed. Since EGNOS will augment the two above mentioned satellite navigation systems and make them suitable for safety critical applications such as flying aircraft or navigating ships through narrow channels the ionospheric propagation errors have to be mitigated as much as possible

Determination of cadmium (II) and zinc (II) in olive oils by derivative potentiometric stripping analysis

A method for the determination of cadmium (II) and zinc (II) in olive oils by derivative potentiometric stripping analysis after dry ashing of the sample is described. The metal ions were concentrated as their amalgams on a glassy carbon working electrode that was previously coated with a thin mercury film and then stripped by a suitable oxidant. Potential and time data were digitally converted into dt dE 121, and E was plotted vs. dt dE 121, thus increasing sensitivity of the method and improving resolution of the analysis. Quantitative analysis was carried out by the method of standard additions; a good linearity was obtained in the range of concentrations examined. Recoveries of 92\u2013102% for cadmium (II) and of 89\u201399% for zinc (II) were obtained from an olive oil spiked at different levels. The detection limits were 5.1 ng g 121 for cadmium (II) and 7.6 ng g 121 for zinc (II)

Determination of cadmium (II) and lead (II) in whole and skim milk by stripping chronopotentiometric analysis

A method for the determination of cadmium (II) and lead (II) in whole and skim milk by stripping chronopotentiometric analysis is described. The metal ions were concentrated as their amalgams on a glassy carbon working electrode that was previously coated with a thin mercury film and then stripped by a suitable oxidant. Potential and time data were digitally converted into dt dE-1, and E was plotted vs. dt dE-1, thus increasing both sensitivity of the method and resolution of the analysis. Quantitative analysis was carried out by the method of standard additions. A good linearity was obtained in the range of concentrations examined. Recoveries of 94-100% for cadmium (II) and of 91-98% for lead (II) were obtained from a sample spiked at different levels. The detection limits were 4.4 ng g-1 for cadmium (II) and 8.6 ng g-1 for lead (II) and the relative standard deviations (mean of nine determinations) were 4.1 and 5.6%, respectively. Results obtained on commercial whole and skim milk were not significantly different from those obtained by inductively coupled plasma atomic emission spectrometry

Characterisation of Columbite-Tantalite (Coltan) ore from Congo. Elemental composition by total reflection X-ray fluorescence analysis

The paper describes the analysis of a columbite-tantalite (coltan) mineral ore from Congo by using total reflection X-ray fluorescence (TRXRF) analysis. The sample was mineralised with a lithium tetraborate and lithium metaborate flux mixture. TRXRF allows multi-element analysis in a wide range of concentrations. The results were in good agreement with those obtained by using another alkaline fusion with sodium peroxide

Determination of zinc (II), cadmium (II), lead (II) and copper (II) in common and balsamic vinegar by stripping chronopotentiometry

A method for the determination of zinc (II), cadmium (II), lead (II) and copper (II) in common and balsamic vinegar by stripping chronopotentiometry is described. The metal ions were concentrated as their amalgams on a glassy carbon working electrode that was previously coated with a thin mercury film and then stripped by a suitable oxidant. Potential and time data were digitally converted into dt dE-1, and E was plotted vs. dt dE-1, thus increasing both sensitivity of the method and resolution of the analysis. Quantitative analysis was carried out by the method of standard additions. A good linearity was obtained in the range of concentrations examined. Recoveries of 90-98% for zinc (II), 91- 97% for cadmium (II), 94-98% for lead (II) and 93-97% for copper (II) were obtained from a sample spiked at different levels. The detection limits were 10.6 ng g-1 for zinc (II), 2.2 ng g-1 for cadmium (II), 3.4 ng g-1 for lead (II) and 4.2 ng g-1 for copper (II) and the relative standard deviations (mean of nine determinations) were 4.8, 6.5, 3.2 and 5.3%, respectively. Results obtained on commercial common and balsamic vinegars were not significantly different from those obtained by atomic absorption spectrometr

Relations between electron contentand peak density: regular and extreme behaviour

Electron content statistics offers important information for planning and operation of various application systems that make use of the transionospheric propagation of radio signals. Electron content statistics meet with an important difficulty: the majority of data stem from observations on the radio signals of orbiting satellites. The database for vertical electron content derived from observations of radio signals emitted from geostationary satellites is only very small. Therefore it is important to make use of statistics for peak density from ionosonde measurements. Quantile statistics do not contain information about ionization extremes. Therefore it is necessary to complement the statistics with case studies which reveal unusual and extreme electron content structures in space and in time

An automatic ANN-based procedure for detecting optimal image sequences supporting LS-PIV applications for rivers monitoring

River flow monitoring has recently experienced rapid development due to advancements in optical methods, which are non-intrusive and enhance safety conditions for operators. Surface velocity fields are obtained recording and analyzing displacements of floating tracer materials, artificially introduced or already present on the water surface. River discharge can be assessed coupling the surface velocity fields with geometric data of a cross section. The accuracy of optical techniques is strongly affected by different environmental and hydraulic factors, and software parameterization, with tracer features that often play a prominent role. An adequate density and spatial distribution of tracer is required to ensure a complete characterization of surface velocity fields. In practical applications such conditions might occur only for a limited portion of the entire acquired images sequence. This work proposes an automatic procedure for identifying and extracting the best portion of a recorded video in terms of seeding characteristics and demonstrates how LS-PIV software performances can be enhanced through this approach. The procedure is implemented through a data-driven empirical approach based on an Artificial Neural Network, trained using data collected during an extensive measurement campaign across different rivers in Sicily (Italy). Performances are evaluated in terms of error in reproducing surface velocity profiles along specific transects, where benchmark profiles derived using an Acoustic Doppler Current Profiler are available. The procedure, also tested via numerical simulations on synthetic image sequences, outperformed an approach based on an existing metric for seeding characterization and represents a simple and useful tool for LS-PIV based applications