History of San Marco

A brief history is reported of the first San Marco project, a joint program of the United States and Italy. The Project was a three phase effort to investigate upper air density and associated ionosphere phenomena. The initial phase included the design and development of the spacecraft, the experiments, the launch complex, and a series of suborbital flights, from Wallops Island. The second phase, consisting of designing, fabricating, and testing a spacecraft for the first orbital mission, culminated in an orbital launch also from Wallops Island. The third phase consisted of further refining the experiments and spacecraft instrumentation and of establishing a full-bore scout complex in Kenya. The launch of San Marco B, in April 1967, from this complex into an equatorial orbit, concluded the initial San Marco effort

Scenedesmus biomass productivity and nutrient removal from wet market wastewater, a bio-kinetic study

The current study aims to investigate the production of microalgae biomass as a function for different wet market wastewater ratios (10, 25, 50, 75 and 100%) and Scenedesmus sp. initial concentrations (104 , 105 , 106 , 107 cells/mL) through the phycoremediation process. The biomass production, total nitrogen (TN), total phosphorus (TP) and total organic compounds (TOC) were determined daily. The pseudo-first order kinetic model was used to measure the potential of Scendesmus sp. in removing nutrients while the Verhulst logistic kinetic model was used to study the growth kinetic. The study revealed that the maximum productivity of Scenedesmus sp. biomass was recorded with 106 cells/mL of the initial concentration in 50% wet market wastewater (98.54 mg/L/day), and the highest removal of TP, TN, and TOC was obtained (85, 90 and 65% respectively). Total protein and lipid contents in the biomass yield produced in the wet market wastewater were more than that in the biomass produced in the BBM (41.7 vs. 37.4 and 23.2 vs. 19.2%, respectively). The results of GC–MS confirmed detection of 44 compounds in the biomass from the wet market wastewater compared to four compounds in the BBM. These compounds have several applications in pharmaceutical and personal care products, chemical industry and antimicrobial activity. These findings indicated the applicability of wet market wastewater as a production medium for microalgae biomass

A decametric wavelength radio telescope for interplanetary scintillation observations

A phased array, electrically steerable radio telescope (with a total collecting area of 18 acres), constructed for the purpose of remotely sensing electron density irregularity structure in the solar wind, is presented. The radio telescope is able to locate, map, and track large scale features of the solar wind, such as streams and blast waves, by monitoring a large grid of natural radio sources subject to rapid intensity fluctuation (interplanetary scintillation) caused by the irregularity structure. Observations verify the performance of the array, the receiver, and the scintillation signal processing circuitry of the telescope

Soundings of the ionospheric HF radio link between Antarctica and Spain

Aquest treball ha estat realitzat sota el context del projecte Antàrtic del Grup d’Investigació en Electromagnetisme i Comunicacions de La Salle (Universitat Ramon Llull). L’objectiu d’aquest projecte és l’estudi del canal ionosfèric com a canal de comunicacions digitals i el disseny de modulacions avançades adaptades. Aquest treball de tesi es centra en el sondeig del canal HF al llarg de tres campanyes consecutives des de 2009 fins 2012 entre la Base Antártica Española (BAE) i l’Observatorio de l’Ebre (OE). En primer lloc, a partir del sondeig en banda estreta s’han obtingut la disponibilitat i la freqüència de màxima disponibilitat (FLA) entre la BAE i OE en el període 2009-2012. En segon lloc, el sondeig en banda ampla ens ha permès estimar la relació senyal-soroll en banda ampla, la dispersió temporal (composite multipath spread), la dispersió freqüencial (composite Doppler spread and Doppler frequency shift) i el temps de propagació. En tercer lloc, s’ha investigat la variació intra-diària i inter-diària d’alguns paràmetres (Densitat total d’electrons, freqüències crítiques i la MUF3000) que han estat mesurades en sondeig vertical en quatre estacions situades al llarg del camí entre la BAE i OE. Finalment, s’ha estudiat la correlació entre la FLA de l’enllaç oblic i la MUF300 de les estacions intermèdies properes als punts de reflexió.Este trabajo ha sido realizado en el contexto del proyecto Antártico del Grupo de Investigación en Electromagnetismo y Comunicaciones de La Salle (Universidad Ramon Llull). El objetivo de este proyecto es el estudio del canal ionosférico como canal de comunicaciones digitales además del diseño de modulaciones avanzadas adaptadas. Este trabajo se centra en el sondeo del canal HF a lo largo de tres campañas consecutivas desde 2009 hasta 2012 entre la Base Antártica Española (BAE) y el Observatorio del Ebro (OE). Primero, a partir del sondeo en banda estrecha se han obtenido la disponibilidad y la frecuencia de máxima disponibilidad (FLA) entre la BAE y OE en el periodo 2009-2012. En segundo lugar, el sondeo en banda ancha nos ha permitido estimar la relación señal-ruido en banda ancha, la dispersión temporal (composite multipath spread), la dispersión frecuencial (composite Doppler spread and Doppler frequency shift) y el tiempo de propagación. En tercer lugar, se ha investigado la variación intra-diaria y la inter-diaria de varios parámetros (Densidad total de electrones, frecuencias críticas y la MUF3000) que han sido medidas en sondeo vertical en cuatro estaciones situadas a lo largo del camino entre la BAE y OE.Finalmente, se ha estudiado la correlación entre la FLA del enlace oblicuo y la MUF300 de las estaciones intermedias cercanas a los puntos de reflexión.This work has been done in the context of the Antarctic Project of the Research Group in Electromagnetism and Communications of La Salle (Ramon Llull University). The aim of this project is to study the ionospheric channel as a digital communications channel as well as to design specific advanced modulations specially adapted to it. This work is devoted to the HF channel sounding throughout three consecutive surveys from 2009 to 2012 between the Spanish Antarctic Station (SAS) and the Ebro Observatory (OE). First, the availability and the Frequency of Largest Availability (FLA) of the SAS-OE link have been obtained from the narrowband sounding technique from 2009 to 2012. Second, wideband sounding of the SAS-OE link has been done to estimate the wideband Signal to Noise Ratio (SNR), the time dispersion (composite multipath spread), frequency dispersion (composite Doppler spread and Doppler frequency shift), and the propagation time. Third, there has been an investigation about the day-to-day and inter-day variations of various parameters (e.g., Total Electron Density, critical frequencies, and Maximum Usable Frequency for ground distance MUF(3000)) that have been measured at four Vertical Incidence Sounding (VIS) stations located over the SAS-OE link path throughout three consecutive surveys (from 2009 to 2012). Finally, the correlation between the FLA of the SAS-OE ionospheric link and the MUF(3000) obtained from VIS stations located close to the reflection points of the same link has been studied

Ionospheric effects on terrestrial communications :Working Group 3 overview

Telecommunications via ionospheric reflection of radio signals of ground-based transmitters are a traditional area. However, this technique is still in use in telecommunications, broadcasting, etc. Various problems have not yet been solved and some of them were studied in Working Group 3 (WG3). Structure of WG 3 and the terms of reference of its four working packages are described in the introductory paper by Zolesi and Cander (2004). Here we describe the main results achieved in COST 271 in the following areas: i) large-scale fluctuations of planetary and gravity waves; ii) development of a new type of HF channel simulator; iii) geomagnetic storm effects on the F1-region ionosphere; iv) the sporadic E-layer and spread-F phenomena; v) the HF radio wave propagation over northerly paths; vi) how to increase the bit rate in ionospheric radio links. In general, substantial progress was achieved but some problems remain open for future investigations

The Murchison Widefield Array: the Square Kilometre Array Precursor at low radio frequencies

The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a location chosen for its extremely low levels of radio frequency interference. The MWA operates at low radio frequencies, 80-300 MHz, with a processed bandwidth of 30.72 MHz for both linear polarisations, and consists of 128 aperture arrays (known as tiles) distributed over a ~3 km diameter area. Novel hybrid hardware/software correlation and a real-time imaging and calibration systems comprise the MWA signal processing backend. In this paper the as-built MWA is described both at a system and sub-system level, the expected performance of the array is presented, and the science goals of the instrument are summarised.Comment: Submitted to PASA. 11 figures, 2 table

Influence of lightning on electron density variation in the ionosphere using WWLLN lightning data and GPS data

Includes bibliography.In this study we have demonstrated that a seasonal and diurnal correlation exists between occurrence frequencies of wave-like structures in the form of Traveling Ionospheric Disturbances (TID) in the ionosphere and tropospheric lightning in the mid-latitude region over South Africa. Lightning induced changes in total electron content (TEC) are strongest between September and March, with the more-pronounced effects occurring 12:00 - 22:00 UT, but from April through August there is a low probability of having significant lightning-induced TID occurrence. The strongest oscillations in the total electron content of the ionosphere have dominant periods of range 0.6 to 0.8 and 1.2to 2.5 hours, typical periods for medium scale TIDs and large scale TIDs respectively. Since ionospheric scintillation is caused by irregularities in electron density which act as wave scatterers, it is feasible that lightning-induced TIDs may provide the mechanism for causing the concomitant and co-located changes in ionospheric total electron con-tent that was observed. Both the lightning and the ionospheric irregularity have spatial dependence over South Africa dominating around Bloemfontein. We have also found a strong seasonal and diurnal correlation between occurrence frequencies of the high rate of change of TEC index (ROTI _ 0.8 TECU/min) as a proxy for amplitude scintillationS4 index and lighting stroke rate. The correlation coefficient linking diurnal lightning stroke rate and high ROTI is found to be about 86%. While the seasonal correlation between the monthly average ROTI and average stroke rate is about 70%, the seasonal average ROTI and average stroke rate correlation is found to be about 84%. This there-fore implies that the presence of lightning is a likely cause of the generation of TIDs and subsequent irregularities in the ionosphere

Handbook for MAP, volume 32. Part 1: MAP summary. Part 2: MAPSC minutes, reading, August 1989. MAP summaries from nations. Part 3: MAP data catalogue

Extended abstracts from the fourth workshop on the technical and scientific aspects of mesosphere stratosphere troposphere (MST) radar are presented. Individual sessions addressed the following topics: meteorological applications of MST and ST radars, networks, and campaigns; the dynamics of the equatorial middle atmosphere; interpretation of radar returns from clear air; techniques for studying gravity waves and turbulence, intercomparison and calibration of wind and wave measurements at various frequencies; progress in existing and planned MST and ST radars; hardware design for MST and ST radars and boundary layer/lower troposphere profilers; signal processing; and data management