762 research outputs found
Performance evaluation of electrochemical concentration cell ozonesondes
Laboratory calibrations of more than a hundred electrochemical concentration cell (ECC) ozonesondes were determined relative to UV-photometry. The average intercept and slope, 0 plus or minus 5 nb and 0.96 plus or minus 0.06, respectively, indicate reasonable agreement with UV photometry, but with considerable variation from one ECC ozonesonde to another. The time required to reach 85% of the final reaction to a step-change in ozone concentration was found to average 51 seconds. Application of the individual calibrations to 20 sets of 1976 flight data reduced the average of the differences between ozonesonde and Dobson spectrophotometric measurements of total ozone from 3.9 to 1.3%. A similar treatment of a set of 10 1977 flight records improved the average ECC-Dobson agreement from -8.5 to -1.4%. Although systematic differences were reduced, no significant effect on the random variations was evident
Performance tests on the Kohmyr ECC ozone sonde
The reliability and accuracy of the Kohmyr ECC ozone sonde are determined. Emphasis is placed on establishing and testing for leak-free connections and stable pump flow rates as well as properly adjusting the pumping pressure. Calibration of the Kohmyr ECC ozone sondes and Dasibi monitors is described. Raw ordinate data and ozone connection data are presented in tabular form. The results of a linear regression treatment of the sonde-indicated ozone concentration vs. Dasibi readings for each switch position are included along with averages of the regression parameters over the six sequencing switch positions. It is suggested that sondes and Dasibi monitors be individually calibrated before flight
The National World War II Museum - Entertainment Department
This report contains the details of internship completed at the National WWII Museum in New Orleans, Louisiana. It will discuss the structure and practices of the Museum’s Entertainment Department through a 480 hour internship. Alongside Victoria Reed, the Director of Entertainment, I assumed the role of Entertainment Production Assistant in June of 2015. I completed this internship with the purpose of earning an Arts Administration degree at the University of New Orleans. The Entertainment Department at the National WWII Museum is but a fraction of what makes this organization a successful attraction in the city of New Orleans and the country. The Museum is a rapidly growing institution and there is much potential to expand past traditional museum exhibits with its Entertainment Department. This report will concentrate on the internship roles and responsibilities, strengths, weaknesses, opportunities, and threats of this specific department. It will also address best practices and recommendations specific to the Entertainment Department
The application of laser-Raman light scattering to the determination of sulfate in sea and estuarine waters
Laser-Raman light scattering is a technique for determining sulfate concentrations in sea and estuarine waters with apparently none of the interferences inherent in the gravimetric and titrametric methods. The Raman measurement involved the ratioing of the peak heights of an unknown sulfate concentration and a nitrate internal standard. This ratio was used to calculate the unknown sulfate concentration from a standard curve. The standard curve was derived from the Raman data on prepared nitrate-sulfate solutions. At the 99.7% confidence level, the accuracy of the Raman technique was 7 to 8.6 percent over the concentration range of the standard curve. The sulfate analyses of water samples collected at the mouth of the James River, Hampton, Virginia, demonstrated that in most cases sulfate had a constant concentration relative to salinity in this area
A mass-balance/photochemical assessment of DMS sea-to-air flux as inferred from NASA GTE PEM-West a and B observations
This study reports dimethyl sulfide (DMS) sea-to-air fluxes derived from a mass-balance/photochemical-modeling approach. The region investigated was the western North Pacific covering the latitude range of 0°-30°N. Two NASA airborne databases were used in this study: PEM-West A in September-October 1991 and PEM-West B in February-March 1994. A total of 35 boundary layer (BL) sampling runs were recorded between the two programs. However, after filtering these data for pollution impacts and DMS lifetime considerations, this total was reduced to 13. Input for each analysis consisted of atmospheric DMS measurements, the equivalent mixing depth (EMD) for DMS, and model estimated values for OH and NO3. The evaluation of the EMD took into account both DMS within the BL as well as that transported into the overlying atmospheric buffer layer (BuL). DMS fluxes ranged from 0.6 to 3.0 μmol m-2d-1 for PEM-West A (10 sample runs) and 1.4 to 1.9 μmol m-2d-1 for PEM-West B (3 sample runs). Sensitivity analyses showed that the photochemically evaluated DMS flux was most influenced by the DMS vertical profile and the diel profile for OH. A propagation of error analysis revealed that the uncertainty associated with individual flux determinations ranged from a factor of 1.3 to 1.5. Also assessed were potential systematic errors. The first of these relates to our noninclusion of large-scale mean vertical motion as it might appear in the form of atmospheric subsidence or as a convergence. Our estimates here would place this error in the range of O to 30%. By far the largest systematic error is that associated with stochastic events (e.g., those involving major changes in cloud coverage). In the latter case, sensitivity tests suggested that the error could be as high as a factor of 2. With improvements in such areas as BL sampling time, direct observations of OH, improved DMS vertical profiling, direct assessment of vertical velocity in the field, and preflight (24 hours) detailed meteorological data, it appears that the uncertainty in this approach could be reduced to ±25%. Copyright 1999 by the American Geophysical Union
Historical Resources of the Choke Canyon Reservoir Area in McMullen and Live Oak Counties, Texas; Historical Archaeological Resources of the Choke Canyon Reservoir Area in McMullen and Live Oak Counties, Texas
This is the second in a series of volumes published on the cultural resources of the Choke Canyon reservoir area of southern Texas. Research has been underway in the reservoir basin since 1977 under the terms of Contract No. 7-07-50-V0897 (Nueces River Project) between the Center for Archaeological Research, The University of Texas at San Antonio and the Bureau of Reclamation of the United States Department of the Interior. The original contract constituted Phase I of the cultural resource investigations
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Potential impact of iodine on tropospheric levels of ozone and other critical oxidants
A new analysis of tropospheric iodine chemistry suggests that under certain conditions this chemistry could have a significant impact on the rate of destruction of tropospheric ozone. In addition, it suggests that modest shifts could result in the critical radical ratio HO2/OH. This analysis is based on the first ever observations of CH3I in the middle and upper free troposphere as recorded during the NASA Pacific Exploratory Mission in the western Pacific. Improved evaluations of several critical gas kinetic and photochemical rate coefficients have also been used. Three iodine source scenarios were explored in arriving at the above conclusions. These include: (1) the assumption that the release of CH3I from the marine environment was the only iodine source with boundary layer levels reflecting a low-productivity source region, (2) same as scenario 1 but with an additional marine iodine source in the form of higher molecular weight iodocarbons, and (3) source scenario 2 but with the release of all iodocarbons occurring in a region of high biological productivity. Based on one-dimensional model simulations, these three source scenarios resulted in estimated Ix (Ix =I + IO + HI + HOI + 2I2O2 +INOx) yields for the upper troposphere of 0.5, 1.5, and 7 parts per trillion by volume (pptv), respectively. Of these, only at the 1.5 and 7 pptv level were meaningful enhancements in O3 destruction estimated. Total column O3 destruction for these cases averaged 6 and 30%, respectively. At present we believe the 1.5 pptv Ix source scenario to be more typical of the tropical marine environment; however, for specific regions of the Pacific (i.e., marine upwelling regions) and for specific seasons of the year, much higher levels might be experienced. Even so, significant uncertainties still remain in the proposed iodine chemistry. In particular, much uncertainty remains in the magnitude of the marine iodine source. In addition, several rate coefficients for gas phase processes need further investigating, as does the efficiency for removal of iodine due to aerosol scavenging processes. Copyright 1996 by the American Geophysical Union
Ambient Atmospheric Hydrocarbon Content as Determined by Gas Chromatographic Techniques from Rural Tidewater Virginia in Late Spring 1974
In an attempt to ascertain the naturally generated hydrocarbon contribution to the air quality of the Hampton Roads region of Tidewater Virginia, a series of 27 air samples was obtained in two rural locations during late spring of 1974. These samples were analyzed for their hydrocarbon content (carbon number range C5 to C10) using gas chromatographic techniques. The thirty different hydrocarbon species were identified and monitored in the experiment. Preliminary analysis of the data indicates an average concentration of 397 parts per billion by weight (carbon) for the total non-methane hydrocarbon loading for C5 to C10 during the experiment. This value exceeds the National Primary Air Quality Standards as set by the Environmental Protection Agency
Historical Archaeological Resources of the Choke Canyon Reservoir Area in McMullen and Live Oak Counties, Texas
During previous surveys of the Choke Canyon Reservoir area in Live Oak and McMullen Counties, Texas, 17 historic sites (structures, refuse areas, cemeteries) had been located and examined. Further work in this area is described in this report and is summarized as follows: Most of the above sites and 5 newly located ones underwent surface collection and \u27test excavation. Sites were recorded and the collected artifacts described and classified. Suggested chronology and occupation are correlated with the findings of the historical research study (Everett, Part I of this report). Evidence indicates that the area was most intensively occupied during the second half of the nineteenth century and that the inhabitants were Anglo-American, Black, Mexican, and possibly Mexican-American families. They were dependent on stock raising and strongly affected by the regional economy
The impact of the English calorie labelling policy on the energy content of food offered and purchased in worksite cafeterias: a natural experiment
Background: On 6 April 2022, legislation came into effect in England requiring calorie labels to be applied to food items on menus of larger food businesses. This study aimed to assess the impact of calorie labelling on (a) food purchased and (b) energy content of menu options in worksite cafeterias. Methods: Product-level sales data and energy content of available items was obtained from 142 worksite cafeterias from January 2022-October 2022. Interrupted-time-series (ITS) analysis with level and slope change evaluated daily energy (kcal) purchased per item, and ITS with level change assessed mean energy per option available on menus before and after calorie labelling. Each analysis was conducted 6 weeks and 6 months from implementation. A post-hoc ITS examined weekly energy purchased per item over a longer period (March 2021-October 2022; 135 sites). Results: There was no evidence calorie labelling changed the energy content of foods purchased (6-week: + 0.60 cal/product, 95%CI:-2.54, + 3.75; 6-month: + 1.59 cal/product, 95%CI:-0.96, + 4.16). Post-hoc analyses suggested calorie labels were associated with a reduction in mean energy of items purchased over time (-0.65 kcal/week, 95%CI:-0.81,-0.49), but a significant increase (+ 3 kcal, 95%CI: + 0.43, + 5.60) at the point of implementation. There was a reduction in the mean energy content of menu options at each seasonal menu change (April 2022:-1.79 kcal, 95%CI:-3.42,-0.15; July 2022:-4.18 kcal, 95% CI:-7.65,-0.73). Conclusion: This large observational study in worksite cafeterias found no evidence to indicate the introduction of calorie labelling led to any immediate reduction in energy purchased by customers. There was some evidence of increasing impact over time, possibly associated with changes in menu offerings, but this effect was small and cannot be directly attributed to calorie labelling
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