Electro-thermal rocket Patent

Electrothermal rocket engine using resistance heated heat exchange

Summertime ozone at Mount Washington: Meteorological controls at the highest peak in the northeast

This study examined the synoptic and regional-scale meteorological controls on summertime O3 at Mount Washington, the highest peak (1910 m) in the northeastern United States. Analysis of air mass transport to Mount Washington was conducted for the summers of 1998–2003 using backward trajectories. Distinct patterns in air mass history were revealed using this approach that helped explain extreme variations in O3 mixing ratios. Most enhanced (≥90th percentile) and depleted (≤10th percentile) O3 events were short-lived and spread out over the summer months. Enhanced O3 events at Mount Washington were generally associated with westerly transport, while depleted events corresponded to northwesterly transport. Periods of O3 greater than 80 ppbv during nighttime periods coincided with westerly (71%) and southwesterly (29%) transport. Periods of elevated O3 commonly occurred during regional warm sector flow or on the western edge of a surface anticyclone. Our analysis also identified a stratospheric contribution to a small percentage (∼5%) of extreme O3 events at the site, but more evidence is required to establish the significance of the contribution to background O3levels in this region

Composition and distribution of aerosols over the North Atlantic during the Subsonic Assessment Ozone and Nitrogen Oxide Experiment (SONEX)

We report the mixing ratios of aerosol-associated soluble ions (focusing on SO4= and NO3−) and HNO3 over the North Atlantic during NASA\u27s Subsonic Assessment Ozone and Nitrogen Oxide Experiment (SONEX). The SONEX campaign was designed to quantify the impacts of jet emissions in the North Atlantic Flight Corridor (NAFC) by sampling both directly within and far removed from the organized track system. Beryllium-7 activities were also measured to assess the magnitude of stratospheric influence in the SONEX study region. Mixing ratios of aerosol-associated SO4= and NO3− above 8 km during SONEX were lower than recent measurements over the central United States during the Subsonic Aircraft Contrail and Cloud Effects Special Study (SUCCESS) and the same as those over the remote South Pacific during the Pacific Exploratory Mission-Tropics (PEM-Tropics), suggesting that aircraft emissions cannot yet be a major source of these ions. Furthermore, mean SO4= mixing ratios at high altitudes were 65% higher in regions away from the NAFC than they were directly in the track system just a few hours after peak traffic. Nitric acid mixing ratios at the highest DC-8 sampling altitudes were elevated during SONEX compared to PEM-Tropics, but there was no clear signal of enhancement by jet exhaust. Strong correlations with 7Be indicate that a large fraction of HNO3and aerosol-associated SO4= measured at high altitudes during SONEX were derived from a stratospheric source

Tropospheric sulfate distribution during SUCCESS: Contributions from jet exhaust and surface sources

The distribution of SO4= aerosol over the central US during SUCCESS indicates that surface sources of SO4= and SO2 in the western US caused SO4= enhancements up to 10 km altitude. The mean (median) SO4= mixing ratio in the mid- and upper-troposphere increased from 24 (16) pptv over the Pacific ocean to 58 (29) pptv over the central plains. Above 10 km the SO4=mixing ratio was essentially the same in both regions, and also when the geographic classifications were further partitioned into upper tropospheric and lower stratospheric categories (mean near 40 pptv). No obvious enhancements of SO4= could be detected in jet exhaust plumes, but this may reflect the difficulty of keeping a large airborne sampling platform within a turbulent wake for time periods longer than a few seconds. Expected SO4=enhancements (based on observed CO2 enhancements and emission factors for these two species) were generally much smaller than the variability of ambient SO4= mixing ratios, so our null result does not mean that aircraft do not emit H2SO4

Influence of vertical transport on free tropospheric aerosols over the central USA in springtime

Measurements of the atmospheric aerosol chemical composition during the Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) indicate substantial vertical transport of boundary layer aerosol to the free troposphere over the south-central United States during springtime. Mixing ratios of water-soluble aerosol Ca 2+ at 6 - 12 km altitude exhibited a median mixing ratio of 20 pptv, with 15% of the measurements \u3e 100 pptv and a maximum of ! 235 pptv. In air parcels with enhanced Ca 2+, the ratios K+/Ca 2+, Mg2+/Ca 2+, and Na+/Ca 2+ in the bulk aerosol were distinctly characteristic of those in limestone and/or cement. Significantly enhanced mixing ratios of aerosol SO42-, NO3-, and NH4 + were also concomitant with the elevated Ca 2+, suggesting transport of both crustal and anthropogenic aerosols to the upper troposphere. The mass concentration of water-soluble aerosol material was in the range 0.1 - 6 pg m -3 STP, and estimated crustal dust levels were 7 - 160 pg m \u273 ST

Be-10/Be-7 tracer of atmospheric transport and stratosphere-troposphere exchange

The 10Be/7Be ratio is a sensitive tracer of atmospheric transport and stratosphere-troposphere exchange (STE). Data from five NASA aircraft field missions (PEM: West A and B, Tropics A; SONEX; and SUCCESS) have been assembled to produce the largest data set of 10Be,7Be, and their ratio collected to date (\u3e300 samples). Ratios near 0.60 are indicative of tropospheric air with little stratospheric influence, while higher ratios are found in stratospheric air. Samples from the lower stratosphere were all collected within 2.5 km of the tropopause and had ratios \u3e1.27. Of these lower stratosphere samples only 16% had ratios in excess of 3.0, suggesting that higher ratio air resides away from the tropopause. Seasonality observed in the10Be/7Be ratios results from the downwelling of air with elevated ratios from higher in the stratosphere in the spring and summer (midlatitudes) and from the decay of 7Be during descent in the winter polar vortex (high latitudes). Our results illustrate the complexity of STE and some of the mechanisms through which it occurs, including tropopause folding, mixing associated with subtropical jets, and the effect of synoptic systems such as hurricanes and northeasters. The10Be/7Be ratio provides important information beyond that which can be derived from studies that rely on chemical mixing ratios alone

Soluble acidic species in air and snow at Summit, Greenland

Simultaneous measurements of the concentrations of soluble acidic species in the gas, aerosol and snow phases at Summit, Greenland were made during summer 1993. Mean concentrations of gas phase HCOOH, CH3COOH, and HNO3 (49±28, 32±17 and 0.9±0.6 nmol m−3 STP, respectively) exceeded the concentrations of aerosol-associated HCOO−, CH3COO−, and NO3−by 1–3 orders of magnitude. On average, SO2 concentrations (0.9±0.6 nmol m−3 STP) were approximately 1/3 those of aerosol SO4=, but this ratio varied widely due largely to changes in the concentration of aerosol SO4=. Concentrations of aerosol SO4= plus SO2 consistently exceeded the sum of aerosol NO3− plus HNO3, yet NO3− was 3–20 times as abundant as SO4=in surface snow. Gas phase concentrations of HCOOH and CH3COOH at Summit were unexpectedly as large as those previously reported for several high latitude continental sites. However, carboxylate concentrations in snow were lower than those of SO4=. Our observation of post-depositional loss of these carboxylic acids within hours after a snowfall must partially explain the low concentrations found in snow. The relative abundance of soluble acids in summer snow at Summit was opposite of that in the overlying atmosphere. Our results highlight the need for improved understanding of the processes controlling transfer of soluble atmospheric species between air and snow

Beryllium 7 and Lead 210 in the western hemisphere Arctic atmosphere: Observations from three recent aircraft-based sampling programs

Concentrations of the natural radionuclides 7Be and 210Pb were determined in aerosol samples collected in the western hemisphere Arctic during the recent NOAA Arctic Gas and Aerosol Sampling Program (AGASP 3) and NASA Global Tropospheric Experiment/Arctic Boundary Layer Expeditions (GTE/ABLE 3A and ABLE 3B) missions. Beryllium 7 showed a free tropospheric concentration maximum between 4 and 5 km in the summer of 1990. Previous 7Be data obtained in the late 1950s and early 1960s also indicated a similar vertical distribution of 7Be near 70°N. Injection of stratospheric air through tropopause folds associated with the Arctic jet near 70°N appears to explain the presence of a layer of air near 4–5 km in the high Arctic free troposphere with elevated 7Be concentrations. The vertical distribution of 210Pb showed a distinct difference between the high-Arctic and sub-Arctic in the summer of 1988. At latitudes greater than 65°N, 210Pb concentrations at 3–6 km were elevated compared to those below 1 km. The reverse of this trend was observed near 60°N. These same vertical distributions were also apparent in aerosol SO42−, determined in separate aerosol samples collected on the same flights (Talbot et al., this issue). The results for 210Pb suggest that some of the difference between the summer troposphere in the high- and sub-Arctic is also due to enhanced stratosphere-troposphere exchange in the vicinity of the Arctic jet. These observations, and other findings from ABLE 3A presented in this issue, suggest that for some species the stratosphere may be a principal source influencing their distribution in the Arctic summer troposphere. For example, intrusions of stratospheric air constitute the dominant source term for tropospheric budgets of 7Be and ozone, and may be important in the 210Pb, SO42−, and NOybudgets. Further investigation, including determination of detailed 7Be and 210Pb distributions, is needed to quantify the stratospheric impact on the chemistry of the Arctic troposphere during the summer

Asian dust storm events of spring 2001 and associated pollutants observed in New England by the Atmospheric Investigation, Regional Modeling, Analysis and Prediction (AIRMAP) monitoring network

Between 18 April and 13 May 2001, three statistically extreme dust aerosol events were observed across the entire northeastern United States. High levels of bulk aerosol water-soluble Ca2+ (range = 42–482 pptv) and PM2.5 elemental Ca (range = 19–156 pptv) were observed simultaneously at Atmospheric Investigation, Regional Modeling, Analysis and Prediction (AIRMAP) and Interagency Monitoring of Protected Visual Environments (IMPROVE) stations. On the basis of Ca2+ concentrations, the average bulk dust concentration for all events across all four AIRMAP stations was estimated to be 7.4 μg/m3. There was no evidence of dust outbreaks in North America large enough to explain these events. However, in April 2001, massive dust storms occurred in the Tarim Pendi basin and in the Gobi deserts of southern Mongolia and China. Comparison of elemental ratios of AIRMAP samples to previously reported Asian dust aerosol samples showed that all AIRMAP samples had a chemical composition similar to Asian dust transported over long distances. Within the dust plumes, strong correlations were observed between absorption, scattering, and CO, indicative of an anthropogenic contribution including elemental carbon and SO42− aerosols. Aerosol NO3− was also highly elevated during event days, most likely due to uptake of HNO3 by the dust during transport. A comparison of dust plumes sampled by AIRMAP to those sampled off the Asian coast during the TRACE-P airborne mission and on the U.S. west coast, strongly suggested entrainment of additional pollutants (e.g., CO, aerosol NO3−, and SO42−) as the dust plumes were transported over North America

Public Facilitation of Small Farmer Access to International Food Marketing Channels: An Empirical Analysis of the USDA Market Assistance Program in Armenia

With the continued globalization, rapid channel consolidation, increasing technology, capital, food safety and private grades and standards requirements, many small scale agricultural and horticultural producers from transitional and developing countries are rapidly becoming excluded from international agri-food marketing system. Consequently, governments and international agencies alike are reevaluating the structure, form, and delivery of their assistance programs as they search to identify new delivery mechanisms that can overcome the weaknesses that their traditional programs face within this new business environment. Their challenge is to design programs that facilitate the establishment of economically viable and sustainable market relationships and business models between small-scale producers and the international food marketing system that provide these financially distress producers access to the technological know-how, market knowledge and access, and financial and productive resources required to successively compete. Recent Central and Eastern European (CEE) experiences indicate that foreign direct investment and the entry of multinational firms have successfully facilitated small farmers access to international marketing channels. By entering markets with sufficient capital to ensure contract enforcement and support investment, multinational firms can overcome the pervasive hold-up and underinvestment problems plaguing the sector thereby stimulating investment and growth in agricultural production (Gow & Swinnen, 1998; 2001; Walkenhorst, 2000; Dries & Swinnen, 2004). For numerous reasons access to sufficient foreign direct investment or multinational firms may not be an option for many countries. The obvious question therefore becomes, can an alternative third-party facilitation mechanism for stimulating agriculture be identified apart from the private solutions found in Central and East Europe? Glover and Kusterer (1990), Porter and Philips-Howard (1997), Coulter et al (1999), Eaton and Shepherd (2001), and Simmons (2001) allude to the benefits of public agencies in facilitating firm farmer relationships. However as of now the literature has not identified nor extracted the critical processes and factors required in the design, development and establishment of long-run economically viable and sustainable business models that facilitate small producers' access to international food markets. In this research we develop a theoretical model explaining the critical processes and factors involved in the public facilitation of the establishment of economically sustainable marketing relationships between small producers and agroprocessors in the presence of financial distress and absence of effective enforcement mechanisms. The USDA Market Assistance Program (MAP) in Armenia is used to empirically test the theoretical model as it provides a natural experiment. Aremina's recovery is similar to those observed in other CEE countries; however Armenia's agricultural sector has not experienced the recovery found elsewhere. A key constraining factor has been the lack of foreign direct investment initiated solutions so successfully employed elsewhere (World Bank, 1999; 2002). Without the presence of private solutions that can create self-enforcing relationships and encourage relationship specific investment, the Armenian agricultural sector has remained in a sub optimal equilibrium characterized by deep financial distress and a general lack of investment. The only sub-sectors that have seen growth any growth have had MAP facilitation support. Thus what is unique is that the MAP project appears to provide a public solution rather than a private solution to the problem, as in all the previous research (Gow & Swinnen, 1998; 2001; Foster, 1999; Gow et al, 2000; Walkenhorst, 2000; Dries & Swinnen, 2004; Cocks & Gow, 2003). In order to examine the phenomena of establishment and development of sustainable inter-organizational marketing relationships within the context of Armenian agriculture, the USDA MAP project, and the goat industry, we have used mixed methodological approach combining qualitative and quantitative data collection. Approximately 100 semi-structured interviews were conducted with farmers, industry representatives, local experts, and USDA MAP personnel. In additional, an extensive enumerated survey was implemented questioning 2000 farmers in five sectors over 2003 and 2004. Based upon the extensive interviews 12 different business models and facilitation processes used by the USDA MAP were identified and a suitable stratified survey frame was designed to test the differences between these models. The theoretical model and empirical results indicate that the third party public facilitator, USDA MAP, is critical in facilitating the initial development of the channel and identifying a value proposition in a downstream market. However, economic sustainability requires that the public agency remain an arms-length third party facilitator, rather than being the leader in the development of the channel and thus an integral cog in the channel. The actual development of the marketing channel should be led by an entrepreneur who possesses both the ability to develop the marketing channel and who is trusted by the local community. By leading the development of the channel the private enforcement capital that is created through the development of the channel is created between the entrepreneur and the farmers. Over time this widens the self enforcing range of the relationship, therefore allowing greater shifts in market conditions and decreasing the risk of opportunistic behavior (Gow et al, 2000). By holding the trust and respect of the community the entrepreneur inherently holds private enforcement capital with the rest of the community equivalent to the present value of their reputation or trust individually and collectively with the community (Oliver & Gow, 2002). Additionally, the expectation of a value proposition of a downstream market creates the expectation of private enforcement capital between farmers the entrepreneur through the present value of future returns that the entrepreneur could earn from the value proposition (Gow et al, 2000). Thus the combination of the present value of the entrepreneur's reputation with the farmers in the short term combined with the longer term expectation of future returns through the value proposition and creates sufficient private enforcement capital for the immediate development of a self-enforcing relationship with the farmers.International Relations/Trade,