EDIN0621B Sizing and Performance Results

A launch vehicle was investigated for the Solar Power Satellite System (SPS). The technology level assumed for sizing was that predicted for 1995. The candidate concept designated EDIN0621B is a two stage, winged, series burn vehicle capable of delivering a one million pound payload to low earth orbit. A propulsion system was sized to provide payload circularization at apogee. Any docking, rendezvous or additional Delta V requirements were assumed to be integral to the payload. The EDIN0621B concept used LOX/C3H8 booster engines and uprated Shuttle System main engines in the upper stage. Gross liftoff weight of the baseline vehicle was 18,367,853 pounds. The booster stage required thirteen engines; the upper stage required seven. The vehicle was designed to a liftoff thrust to weight ratio of 1.3

Superconductivity from Undressing. II. Single Particle Green's Function and Photoemission in Cuprates

Experimental evidence indicates that the superconducting transition in high $T_c$ cuprates is an 'undressing' transition. Microscopic mechanisms giving rise to this physics were discussed in the first paper of this series. Here we discuss the calculation of the single particle Green's function and spectral function for Hamiltonians describing undressing transitions in the normal and superconducting states. A single parameter, $\Upsilon$, describes the strength of the undressing process and drives the transition to superconductivity. In the normal state, the spectral function evolves from predominantly incoherent to partly coherent as the hole concentration increases. In the superconducting state, the 'normal' Green's function acquires a contribution from the anomalous Green's function when $\Upsilon$ is non-zero; the resulting contribution to the spectral function is $positive$ for hole extraction and $negative$ for hole injection. It is proposed that these results explain the observation of sharp quasiparticle states in the superconducting state of cuprates along the $(\pi,0)$ direction and their absence along the $(\pi,\pi)$ direction.Comment: figures have been condensed in fewer pages for easier readin

PLOTTER: An independent computer program for the generation of graphical displays

A computer program is described for generating graphical information from input data or auxiliary analysis programs on a variety of graphical devices. Options are presented for tabulating the data in columnar format and for plotting auxiliary text in the vicinity of the plotted information. Display device selection is accomplished by interfacing the basic computer code through routines which convert the internally generated plot vectors to hardware commands for the display device. The plotting techniques employed in the computer program are discussed. User's instructions are presented with examples which illustrate the use of the program in generating plotted information from various sources and presenting the information in alternate plot formats. Technical discussion of the computer code is presented giving the physical characteristics, computer loading instructions and descriptions of the subroutines

Development of the engineering design integration (EDIN) system: A computer aided design development

The EDIN (Engineering Design Integration) System which provides a collection of hardware and software, enabling the engineer to perform man-in-the-loop interactive evaluation of aerospace vehicle concepts, was considered. Study efforts were concentrated in the following areas: (1) integration of hardware with the Univac Exec 8 System; (2) development of interactive software for the EDIN System; (3) upgrading of the EDIN technology module library to an interactive status; (4) verification of the soundness of the developing EDIN System; (5) support of NASA in design analysis studies using the EDIN System; (6) provide training and documentation in the use of the EDIN System; and (7) provide an implementation plan for the next phase of development and recommendations for meeting long range objectives

Superconductivity from Undressing

Photoemission experiments in high $T_c$ cuprates indicate that quasiparticles are heavily 'dressed' in the normal state, particularly in the low doping regime. Furthermore these experiments show that a gradual undressing occurs both in the normal state as the system is doped and the carrier concentration increases, as well as at fixed carrier concentration as the temperature is lowered and the system becomes superconducting. A similar picture can be inferred from optical experiments. It is argued that these experiments can be simply understood with the single assumption that the quasiparticle dressing is a function of the local carrier concentration. Microscopic Hamiltonians describing this physics are discussed. The undressing process manifests itself in both the one-particle and two-particle Green's functions, hence leads to observable consequences in photoemission and optical experiments respectively. An essential consequence of this phenomenology is that the microscopic Hamiltonians describing it break electron-hole symmetry: these Hamiltonians predict that superconductivity will only occur for carriers with hole-like character, as proposed in the theory of hole superconductivity

Exotic coloured fermions and lepton number violation at the LHC

Majorana neutrino mass models with a scale of lepton number violation (LNV) of order TeV potentially lead to signals at the LHC. Here, we consider an extension of the standard model with a coloured octet fermion and a scalar leptoquark. This model generates neutrino masses at 2-loop order. We make a detailed MonteCarlo study of the LNV signal at the LHC in this model, including a simulation of standard model backgrounds. Our forecast predicts that the LHC with 300/fb should be able to probe this model up to colour octet fermion masses in the range of (2.6-2.7) TeV, depending on the lepton flavour of the final state.Comment: 14 pages, 2 figure

Effects of Maintenance on Terminal Fixed-Ratio and Fixed-Interval Schedules of Reinforcement on Generalizations Gradients

No abstract was provided