A low mass time expansion chamber (TEC) has been developed to measure distributions of position and angle of the TRIUMF low energy surface muon beam used for the TWIST experiment. The experiment is a high precision measurement of muon decay and is dominated by systematic uncertainties, including the stability, reproducibility, and characterization of the beam. The distributions measured by the ...

This paper studies the ionospheric response to a major geomagnetic storm of October 18-19, 1995, using the thermosphere-ionosphere electrodynamics general circulation model (TIEGCM) simulations and the global ionospheric maps (GIM) of total electron content (TEC) observations from the Global Positioning System (GPS) worldwide network. The TIE-GCM results, which utilize the realistic time-depend...

A regression-based model was previously developed to forecast total electron content (TEC) at middle latitudes. We present a more sophisticated using neural networks (NN) instead of linear regression. This regional prototype simulates and forecasts TEC variations in relation space weather conditions. The development consisted the selection best set predictors, NN architecture, length input seri...

On 20 September 1999 UT (21 September in local time, LT) a large earthquake Mw=7.7 struck central Taiwan near the small town of Chi-Chi. The greatest plasma frequency in the ionosphere, foF2, observed by the ChungLi ionosonde (25.0N, 121.2E) reveals three clear precursors at 1, 3, and 4 days prior to the earthquake. This paper examines the ionospheric total electron content (TEC) observed by a ...

Global Navigation Satellite System (GNSS) measurements of the Total Electron Content (TEC) from local (Dourbes, 50.1oN, 04.6oE) and European IGS (International GNSS Service) stations were used to obtain the TEC changes during the geomagnetic storms of the latest solar activity cycle. A common epoch analysis, with respect to geomagnetic storm intensity, season, and latitude, was performed on dat...

This paper reports on a fuzzy logic correction technique for the IRI90 climatological ionospheric model that uses a sparse set of GPS total electron content (TEC) measurements to provide a significant model correction over the entire sub-solar equatorial bulge. Crisp inputs, represented by a sparse set of GPS measurements of ionospheric TEC, are ingested into the fuzzy correction model which is...

PURPOSE We previously reported that human tumor-derived endothelial cells (TEC) have an angiogenic phenotype related to the autocrine production of several angiogenic factors. The purpose of the present study was to evaluate whether an enhanced synthesis of platelet-activating factor (PAF) might contribute to the proangiogenic characteristics of TEC and whether its inactivation might inhibit an...

The estimation of Total Electron Content (TEC) in the equatorial ionosphere using GPS presents a number of challenges due to the presence of strong spatio-temporal density gradients and scintillation of the satellite signals caused by F-region irregularities. In this paper we describe a methodology for real-time calibrated TEC estimation in the presence of scintillation and a highly structured ...

Signal phase measured by GPS signal processors is crucial for high-resolution range measurement. However, the measured signal phase must be corrected for the the dispersive phase advance imposed by the earth’s ionosphere. Dual-frequency measurements exploit frequency dependence to isolate and correct the ionosphere-induced phase change. The correction is proportional to total electron content (...