Study of basin scale acoustic transmissions

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1992A basin-scale acoustic tomography experiment was conducted in the northeast Pacific from May 1987 to September 1987. In this thesis, the stability of the forward model is analyzed. There are large non-linearities in the changes in travel time between ray paths for the four seasons . I constructed a model in which the change in warming in the upper 100 m of the ocean was due only to changes in surface solar irradiance. The value of the surface solar irradiance anomalies necessary to cause the tomography results for warming (Spiesberger and Metzger, 1991) was computed. This value was larger than the actual value of surface solar irradiance anomaly which was computed using inputs measured by satellite (Chertock, 1989)

On-Line Team Project Communication Tool Set

Team projects offer a valuable mechanism for effective learning. However, communication within the team, with the instructor and between different teams is a challenging task that can greatly limit the effectiveness of the learning experience. Some of the tools and concepts that are being developed for distance learning applications can be used to enhance team project communication within teams that are geographically separated as well as for in-campus teams. This article documents a set of on-line tools that allow for asynchronous team participation and timely monitoring and feedback by the instructor

A Space Weather and Terrestrial Hazards Experiment for the MSTI Program

This paper discusses the instrumentation being built under BMDO auspices to construct a small, lightweight, low-cost satellite that provides measurements of local hazards affecting satellites in low-Earth orbit. In the following, we describe the objectives of the mission, the instrumentation being built and the mission profile for acquisition and utilization of the data products

The Role of Social Protection Programs in Remittance-Centered Development Policy: A Case Study of Morocco

Remittances serve as a financial lifeline for households in emerging economies around the world, affording basic social services such as food, education, and healthcare. Alternatively, remittances from diaspora populations are an opportunity for countries to finance development projects. The case of Morocco illustrates the central role that remittances can play in the development policy of countries with high labor out-migration. Yet using remittances for long-term development requires public social protection programs to substitute for the redirection of these private funds used by individual households

Particulate PAH Emissions from Residential Biomass Combustion: Time-Resolved Analysis with Aerosol Mass Spectrometry

Time-resolved emissions of particulate polycyclic aromatic hydrocarbons (PAHs) and total organic particulate matter (OA) from a wood log stove and an adjusted pellet stove were investigated with high-resolution time-of-flight aerosol mass spectrometry (ANIS). The highest OA emissions were found during the addition of log wood on glowing embers, that is, slow burning pyrolysis conditions. These emissions contained about 1% PAHs (of OA). The highest PAH emissions were found during fast burning under hot air starved combustion conditions, in both stoves. In the latter case, PAHs contributed up to 40% of OA, likely due to thermal degradation of other condensable species. The distribution of PAHs was also shifted toward larger molecules in these emissions. ANIS signals attributed to PAHs were found at molecular weights up to 600 Da. The vacuum aerodynamic size distribution was found to be bimodal with a smaller mode (D-va similar to 200 nm) dominating under hot air starved combustion and a larger sized mode dominating under slow burning pyrolysis (D-va similar to 600 nm). Simultaneous reduction of PAHs, OA and total particulate matter from residential biomass combustion may prove to be a challenge for environmental legislation efforts as these classes of emissions are elevated at different combustion conditions