Plasma in the Jovian magnetosphere

It is shown that the plasma in Jupiter's ionosphere is collisionless above a certain level. In the outer magnetosphere, where the rotational force dominates the gravitational force, the collisionless plasma has a beam-like distribution and gives rise to a two-stream instability. This leads to trapping of plasma in the centrifugally dominated region of the magnetosphere. Plasma is lost by recombination. Equilibrium-trapped particle densities are calculated by requiring a balance between trapping by wave-particle interaction and loss by recombination. The results are compared with recent observations from Pioneer 10. It is suggested that the observations require an unexplained ion-heating mechanism. Some consequences of the model are discussed

Interaction of a neutral cloud moving through a magnetized plasma

Current collection by outgassing probes in motion relative to a magnetized plasma may be significantly affected by plasma processes that cause electron heating and cross field transport. Simulations of a neutral gas cloud moving across a static magnetic field are discussed. The authors treat a low-Beta plasma and use a 2-1/2 D electrostatic code linked with the authors' Plasma and Neutral Interaction Code (PANIC). This study emphasizes the understanding of the interface between the neutral gas cloud and the surrounding plasma where electrons are heated and can diffuse across field lines. When ionization or charge exchange collisions occur a sheath-like structure is formed at the surface of the neutral gas. In that region the crossfield component of the electric field causes the electron to E times B drift with a velocity of the order of the neutral gas velocity times the square root of the ion to electron mass ratio. In addition a diamagnetic drift of the electron occurs due to the number density and temperature inhomogeneity in the front. These drift currents excite the lower-hybrid waves with the wave k-vectors almost perpendicular to the neutral flow and magnetic field again resulting in electron heating. The thermal electron current is significantly enhanced due to this heating

Improved head-controlled TV system produces high-quality remote image

Manipulator operator uses an improved resolution tv camera/monitor positioning system to view the remote handling and processing of reactive, flammable, explosive, or contaminated materials. The pan and tilt motions of the camera and monitor are slaved to follow the corresponding motions of the operators head

Improved electromechanical master-slave manipulator

Electric master-slave manipulator uses force multiplication and allows the operator to remotely control the slave arm. Both the master and slave arms execute seven distinct motions by a specially designed force-reflecting servo having a one to one correspondence between the motion at the master and slave

Dimensions of some affine Deligne-Lusztig varieties

This paper concerns the dimensions of certain affine Deligne-Lusztig varieties, both in the affine Grassmannian and in the affine flag manifold. Rapoport conjectured a formula for the dimensions of the varieties X_mu(b) in the affine Grassmannian. We prove his conjecture for b in the split torus; we find that these varieties are equidimensional; and we reduce the general conjecture to the case of superbasic b. In the affine flag manifold, we prove a formula that reduces the dimension question for X_x(b) with b in the split torus to computations of dimensions of intersections of Iwahori orbits with orbits of the unipotent radical. Calculations using this formula allow us to verify a conjecture of Reuman in many new cases, and to make progress toward a generalization of his conjecture.Comment: 51 pages, 12 figure

Radial diffusion in Jupiter's magnetosphere

Radial phase space density profiles for equatorially mirroring particles are computed from the data of the University of Iowa packages on Pioneer 10. The profiles are only consistent with radial diffusion subject to nonadiabatic losses. It is suggested that these losses are due to pitch angle scattering by whistler turbulence

High resolution measurements of density structures in the Jovian plasma sheet

A recent effort to digitize the plasma density by using the low frequency cutoff of trapped continuum radiation in the vicinity of the Jovian plasma sheet has revealed the existence of sharply defined density structures in the plasma sheet. These structures typically have a plasma density which is relatively constant but of order 50 percent greater or less than in the surrounding plasma. At the boundaries of these structures, the transitions from low to high density occur on time scales of about ten seconds, which correspond to spatial dimensions on the order of a few ion Larmor radii. The structures themselves last for intervals from less than a minute to more than five minutes, corresponding to size scales from a fraction of a Jovian radius to more than a Jovian radius, depending of the velocity of the structure relative to the spacecraft. In view of the importance of near corotation plasma flows, these structures are likely to be limited in both the longitudinal and radial dimensions and, therefore, could represent flux tubes with greatly varying plasma content. These observations are presented as among the first to directly address the theoretically proposed interchange instability

Assessment and Accountability Systems in the 50 States: 1999-2000

In the late 1990s and early 2000, all 50 states embarked on education initiatives related to high standards and challenging content. A central focus of these efforts was on the establishment of standards-based reforms and assessments that measured student performance and accountability systems that were at least partially focused on student outcomes. The policy talk asserted that these high standards apply to all students, and standards-based reform focused on high achievement for all children. Much of this activity took place within the context of the Improving America’s Schools Act (IASA) of 1994. This law created major changes in Title I of the Elementary and Secondary Education Act, the $8 billion federal program that provides additional funding to schools with large concentrations of poor children. The legislation was developed in response to concerns about the operation and impact of the Title I program over the previous 25 years: low expectations for educationally disadvantaged students, an instructional emphasis on basic skills, isolation from the regular curriculum, and a focus on procedural compliance rather than academic outcomes (U.S. Department of Education, 1993). Researchers, policymakers, and advocates concluded that a new federal approach was needed to improve education for all students—an approach built on a framework of standards-based reform that is integrated with state and local education reform initiatives. The provisions of IASA gave states a prominent role in Title I. States were expected to establish challenging content and performance standards, implement assessments that measure student performance against these standards, hold schools and school systems accountable for the achievement of all students, and take other steps that promote programmatic flexibility and foster instructional and curricular reform. States were also expected to align their Title I programs with these policies to ensure that disadvantaged students are held to the same high standards. In addition, the 1997 revisions to the Individuals with Disabilities Education Act (IDEA) require states to include students having disabilities in state and district assessment programs, with appropriate accommodations, and to disaggregate and report their test scores. This report uses data collected from the 50 states to describe state assessment and accountability systems and to examine the extent to which state policies meet the objectives of federal policy

ENERGY BASED SEISMIC DESIGN OF A TIMBER CORE-WALL MULTI-STOREY HYBRID BUILDING

Current earthquake design philosophy in North America recommends an equivalent static force procedure (ESFP). Much research lately has been in new performance based methodologies including direct displacement based design (DDBD) and energy-based design (EBD). Research in energy-based design has not had the attention of DDBD yet now is gaining in popularity because of the methods reliance on the velocity spectrum and duration of earthquake hazard. This paper discusses an energy based methodology in designing a novel multi-storey hybrid building consisting of a timber-steel core wall system. This hybrid system combines Cross Laminated Timber (CLT) panels with steel plates and connections to provide the required strength and ductility to core walled buildings. To improve the applicability of the hybrid system an EBD methodology is proposed to design the core-walled building. The methodology is proposed as it does not rely on empirical formulas and force modification factors to determine the final design of the structure. In order to assess the feasibility of the EBD method, it is implemented in the design of a 7-storey building based off an already built concrete benchmark building. The design is first carried out following the ESFP outlined by the National Building Code of Canada for Vancouver, BC. Nonlinear time history analysis is carried out on the ESFP design and the proposed EBD methodology using 10 ground motions selected at 2% in 50 years return period, to evaluate the suitability of the method and the results of the ESFP and EBD methodologies are discussed and compared