Another View of the Maximum Principle for Infinite-Horizon Optimal Control Problems in Economics

We present a recently developed complete version of the Pontryagin maximum principle for a class of infinite-horizon optimal control problems arising in economics. The peculiarity of the result is that the adjoint variable is explicitly specified by a formula which resembles the Cauchy formula for solutions of linear differential systems. In certain situations this formula implies the “standard” transversality conditions at infinity. Moreover, it can serve as their alternative. We provide examples demonstrating the ad- vantage of the suggested version of the maximum principle. In particular, we consider its applications to Halkin’s example, to Ramsey’s optimal growth model and to a basic model of optimal extraction of a non-renewable resource. An economic interpretation of the developed characterization of the adjoint variable is also presented

Heavy-Ion Beam Acceleration of Two-Charge States from an Ecr Ion Source

This paper describes a design for the front end of a superconducting (SC) ion linac which can accept and simultaneously accelerate two charge states of uranium from an ECR ion source. This mode of operation increases the beam current available for the heaviest ions by a factor of two. We discuss the 12 MeV/u prestripper section of the Rare Isotope Accelerator (RIA) driver linac including the LEBT, RFQ, MEBT and SC sections, with a total voltage of 112 MV. The LEBT consists of two bunchers and electrostatic quadrupoles. The fundamental frequency of both bunchers is half of the RFQ frequency. The first buncher is a multiharmonic buncher, designed to accept more than 80% of each charge state and to form bunches of extremely low longitudinal emittance (rms emittance is lower than 0.2 keV/u nsec) at the output of the RFQ. The second buncher is located directly in front of the RFQ and matches the velocity of each charge-state bunch to the design input velocity of the RFQ. We present full 3D simulations of a two-charge-state uranium beam including space charge forces in the LEBT and RFQ, realistic distributions of all electric and magnetic fields along the whole prestripper linac, and the effects of errors, evaluated for several design options for the prestripper linac. The results indicate that it is possible to accelerate two charge states while keeping emittance growth within tolerable limits.Comment: LINAC2000, MOD0

Modernization of government management in empires of new time: comparative political analysis

The article deals with the issues related to the modernization of public administration in the imperial states of modern times. Russian, British and Ottoman empires as states implementing various strategies of modernization and improvement of public administration were chosen as examples. The success of modernization reforms of the administration is one of the essential conditions for maintaining stability and development of the imperial political system, formalizing the domination of the center in relation to the periphery. The Ottoman Empire failed to implement the policy of modernization of public administration in a timely and consistent manner. The British Empire was combined the strategies of centralization and decentralization of state management of its overseas colonies. The Russian Empire - a special imperial system -implemented, within the framework of the unitary state, the principle of centralization of the system of management, but its implementation in the development of the central bureaucratic apparatus of the empire was limited by the autocratic monarchy. At the same time, the Russian Empire was flexible in terms of differentiation of the management approaches. The article substantiates the conclusion that the imperial administration was an expression of centripetal political processes in the imperial system provided them and was an expression of the political power of the center which has an autocratic character in relation to the periphery. The processes associated with the administration of the Empire are concentrated in its center and implemented in addition to the will of the periphery. In institutional terms, the center of the empire is represented by general imperial authorities and management, in functional terms, the imperial power has exclusive administrative prerogatives associated with the concentration of resources of power and their distribution over the imperial hierarchy. The differentiation of administrative approaches shows the administrative and political specificity of the empire-state. In general the modernization of management empire became a significant factor in allowing the empire to most effectively carry out the concentration of political resources

LUMINESCENCE OF CADMIUM SULFIDE QUANTUM DOTS IN FLUOROPHOSPHATE GLASSES

Cadmium sulfide quantum dots are perspective materials in optics, medicine, biology and optoelectronics. Fluorophosphate glasses, doped with cadmium sulfide quantum dots, were examined in the paper. Heat treatment led to the formation of quantum dots with diameters equal to 2.8 nm, 3.0 nm and 3.8 nm. In view of such changes in the quantum dots size the fundamental absorption edge shift and the luminescence band are being displaced to the long wavelengths. Luminescence lifetime has been found to be dependent on the registration wavelength in the range from 450 to 700 nm. Obtained fluorophosphate glasses with CdS quantum dots can find their application as fluorescent materials with intensive luminescence band and long excited-state natural lifetime

Mushy Layer Formation during Solidification of Binary Alloys from a Cooled Wall: the Role of Boundary Conditions

Motivated by metallurgical and geophysical applications we present a mathematical model describing the process of unidirectional solidification of binary melts or solutions, which is based on the classical Stefan thermodiffusion theory with a planar front up to a time of mushy layer initiation and on the quasi-equilibrium theory of solidification with a constitutionally supercooled region afterwards. The role of boundary conditions imposed at the cooled wall is studied in terms of heat flux coefficients describing ultimately nonlinear dynamics of the process

Application of ILC super conducting cavities for acceleration of protons

Beam acceleration in the International Linear Collider (ILC) will be provided by 9-cell 1300 MHz superconducting (SC) cavities. The cavities are designed for effective acceleration of charged particles moving with the speed of light and are operated on {pi}-mode to provide maximum accelerating gradient. Significant R&D effort has been devoted to develop ILC SC technology and its RF system which resulted excellent performance of ILC cavities. Therefore, the proposed 8-GeV proton driver in Fermilab is based on ILC cavities above {approx}1.2 GeV. The efficiency of proton beam acceleration by ILC cavities drops fast for lower velocities and it was proposed to develop squeezed ILC-type (S-ILC) cavities operating at 1300 MHz and designed for {beta}{sub G} = 0.81, geometrical beta, to accelerate protons or H{sup -} from {approx}420 MeV to 1.2 GeV. This paper discusses the possibility of avoiding the development of new {beta}{sub G} = 0.81 cavities by operating ILC cavities on 8/9{pi}-mode of standing wave oscillations

Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts.

The dipole configuration of the Earth's magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes