Mechanism of Gravity Impulse

It is well-known that energy-momentum is the source of gravitational field. For a long time, it is generally believed that only stars with huge masses can generate strong gravitational field. Based on the unified theory of gravitational interactions and electromagnetic interactions, a new mechanism of the generation of gravitational field is studied. According to this mechanism, in some special conditions, electromagnetic energy can be directly converted into gravitational energy, and strong gravitational field can be generated without massive stars. Gravity impulse found in experiments is generated by this mechanism.Comment: 10 page

Searching for the WγW \gamma decay of a charged Higgs boson

We study the prospects for charged Higgs boson searches in the $W \gamma$ decay channel. This loop-induced decay channel can be important if the charged Higgs is fermiophobic, particularly when its mass is below the $WZ$ threshold. We identify useful kinematic observables and evaluate the future Large Hadron Collider sensitivity to this channel using the custodial-fiveplet charged Higgs in the Georgi-Machacek model as a fermiophobic benchmark. We show that the LHC with 300~fb$^{-1}$ of data at 14~TeV will be able to exclude charged Higgs masses below about 130~GeV for almost any value of the SU(2)$_L$-triplet vacuum expectation value in the model, and masses up to 200~GeV and beyond when the triplet vacuum expectation value is very small. We describe the signal simulation tools created for this analysis, which have been made publicly available.Comment: 32 pages, 12 figures and 4 tables; v2: references added, typo fixed, match the published versio

Cavity flow past a slender pointed hydrofoil

A slender-body theory for the flow past a slender, pointed hydrofoil held at a small angle of Attack to the flow, with a cavity on the upper surface, has been worked out. The approximate solution valid near the body is seen to be the sum of two components. The first consists of a distribution of two-dimensional sources located along the centroid line of the cavity to represent the variation of the cross-sectional area of the cavity. The second component represents the crossflow perpendicular to the centroid line. It is found that over the cavity boundary which envelops a constant pressure region, the magnitude of the cross-flow velocity is not constant, but varies to a moderate extent. With this variation neglected only in the neighbourhood of the hydrofoil, the cross-flow is solved by adopting the Riabouchinsky model for the two-dimensional flow. The lift is then calculated by integrating the pressure along the chord; the dependence of the lift on cavitation number and angle of attack is shown for a specific case of the triangular plan form

Current-Voltage Characteristics of Polymer Light-Emitting Diodes

Conduction in pristine conjugated polymers (other than polyacetylene) is by polaron hopping between sites corresponding to conjugation lengths. The strong increase of current $I$ with voltage $V$ observed for both emission-limited and ohmic contacts is due in large part to mobility increase as increasing field makes it more possible to overcome internal barriers, such as energy differences between sites. For emission-limited contacts an additional source of nonlinear increase of $I$ with increasing $V$ is greater ability to escpe return to the injecting electrode due to the image force. For ohmic contacts additional nonlinearity comes from space charge effects. We are able to fit $I$ vs. $V$ for electron or hole conduction in some poly($p$-phenylene vinylene), PPV, derivatives with ohmic contacts for reasonable values of the parameters involved.Comment: 9 pages, REVTeX, 1 figure is aviable upon request, to be published in SPIE pro

Strength theories of composites: Status and issues

The longitudinal strength of fibrous composites is studied. A probability model for the strength of fibrous materials is described. Failure modes are observed

No functions continuous only at points in a countable dense set

We give a short proof that if a function is continuous on a countable dense set, then it is continuous on an uncountable set. This is done for functions defined on nonempty complete metric spaces without isolated points, and the argument only uses that Cauchy sequences converge. We discuss how this theorem is a direct consequence of the Baire category theorem, and also discuss Volterra's theorem and the history of this problem. We give a simple example, for each complete metric space without isolated points and each countable subset, of a real-valued function that is discontinuous only on that subset.Comment: Expanded the result and added historical references and discussio

Operational solar forecasting for the real-time market

Despite the significant progress made in solar forecasting over the last decade, most of the proposed models cannot be readily used by independent system operators (ISOs). This article proposes an operational solar forecasting algorithm that is closely aligned with the real-time market (RTM) forecasting requirements of the California ISO (CAISO). The algorithm first uses the North American Mesoscale (NAM) forecast system to generate hourly forecasts for a 5-h period that are issued 12 h before the actual operating hour, satisfying the lead-time requirement. Subsequently, the world's fastest similarity search algorithm is adopted to downscale the hourly forecasts generated by NAM to a 15-min resolution, satisfying the forecast-resolution requirement. The 5-h-ahead forecasts are repeated every hour, following the actual rolling update rate of CAISO. Both deterministic and probabilistic forecasts generated using the proposed algorithm are empirically evaluated over a period of 2 years at 7 locations in 5 climate zones