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This paper reports on the results of the study to identify technologies that could have a significant impact on Earth Science mission operations when looking out at the 5-15 year horizon (through 2025). The potential benefits of t...
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This paper reports on the results of the study to identify technologies that could have a significant impact on Earth Science mission operations when looking out at the 5-15 year horizon (through 2025). The potential benefits of the new technologies will be discussed, as well as recommendations for early research and development, prototyping, or analysis for these technologies.
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Ninety-six percent of commercial buildings in the United States are small- to medium-sized, use nearly 18 percent of the country's energy, and shelter a large proportion of population, thus underlining the importance of understand...
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Ninety-six percent of commercial buildings in the United States are small- to medium-sized, use nearly 18 percent of the country's energy, and shelter a large proportion of population, thus underlining the importance of understanding the relationship between ventilation, energy use, and air quality. This field study of 37 such buildings throughout California obtained information on all aspects of ventilation and levels of indoor air pollutants. The study included seven retail establishments: five restaurants; eight offices; two gas stations, hair salons, healthcare facilities, grocery stores, dental offices, and fitness gyms; and five other buildings. Sixteen (43 percent) of the buildings were not designed to or did not provide mechanically supplied outdoor ventilation air. In some cases the air handling unit was a residential rather than a commercial model, thereby failing to meet applicable ventilation standards. Low-efficiency air filters were frequently observed. The air exchange rate averaged 1.6 with a standard deviation of 1.7 exchanges per hour and was similar between buildings with and without mechanically supplied outdoor air, indicating that buildings have significant leakage, in contrast to California homes. Compared against Title 24 standards, healthcare establishments, gyms, offices, hair salons, and retail stores were ventilated below the required rates, not meeting Title 24 ventilation requirements; restaurants and gas stations had rates above the standard, meeting ventilation requirements.
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摘要 :
Ninety-six percent of commercial buildings in the United States are small- to medium-sized, use nearly 18 percent of the country's energy, and shelter a large proportion of population, thus underlining the importance of understand...
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Ninety-six percent of commercial buildings in the United States are small- to medium-sized, use nearly 18 percent of the country's energy, and shelter a large proportion of population, thus underlining the importance of understanding the relationship between ventilation, energy use, and air quality. This field study of 37 such buildings throughout California obtained information on all aspects of ventilation and levels of indoor air pollutants. The study included seven retail establishments: five restaurants; eight offices; two gas stations, hair salons, healthcare facilities, grocery stores, dental offices, and fitness gyms; and five other buildings. Sixteen (43 percent) of the buildings were not designed to or did not provide mechanically supplied outdoor ventilation air. In some cases the air handling unit was a residential rather than a commercial model, thereby failing to meet applicable ventilation standards. Low-efficiency air filters were frequently observed. The air exchange rate averaged 1.6 with a standard deviation of 1.7 exchanges per hour and was similar between buildings with and without mechanically supplied outdoor air, indicating that buildings have significant leakage, in contrast to California homes. Compared against Title 24 standards, healthcare establishments, gyms, offices, hair salons, and retail stores were ventilated below the required rates, not meeting Title 24 ventilation requirements; restaurants and gas stations had rates above the standard, meeting ventilation requirements.
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Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two n...
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Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100 percent, and were often greater than 25 percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems.
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We investigated the relationship of ventilation rates with the performance of advice nurses working in a call center. Ventilation rates were manipulated; temperatures, humidities, and CO(sub 2) concentrations were monitored; and w...
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We investigated the relationship of ventilation rates with the performance of advice nurses working in a call center. Ventilation rates were manipulated; temperatures, humidities, and CO(sub 2) concentrations were monitored; and worker performance data, with 30-minute resolution, were collected. Multivariate linear regression was used to investigate the association of worker performance with indoor minus outdoor CO(sub 2) concentration (which increases with decreasing ventilation rate per worker) and with building ventilation rate. Results suggest that the effect of ventilation rate on worker performance in this call center was very small (probably less than 1%) or nil, over most of the range of ventilation rate (roughly 12 L s(sup -1) to 48 L s(sup -1) per person). However, there is some evidence of worker performance improvements of 2% or more when the indoor CO(sub 2) concentration exceeded the outdoor concentration by less than 75 ppm.
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In previous studies, increased ventilation rates and reduced indoor carbon dioxide concentrations have been associated with improvements in health at work and increased performance in work-related tasks. Very few studies have asse...
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In previous studies, increased ventilation rates and reduced indoor carbon dioxide concentrations have been associated with improvements in health at work and increased performance in work-related tasks. Very few studies have assessed whether ventilation rates influence performance of real work. This paper describes part one of a two-part analysis from a productivity study performed in a call center operated by a health maintenance organization. Outside air ventilation rates were manipulated, indoor air temperatures, humidities, and carbon dioxide concentrations were monitored, and worker performance data for advice nurses, with 30-minute resolution, were analyzed via multivariate linear regression to look for an association of performance with building ventilation rate, or with indoor carbon dioxide concentration (which is related to ventilation rate per worker).
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To test proposed methods for reducing SBS symptoms and to learn about the causes of these symptoms, a double-blind controlled intervention study was designed and implemented. This study utilized two different interventions designe...
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To test proposed methods for reducing SBS symptoms and to learn about the causes of these symptoms, a double-blind controlled intervention study was designed and implemented. This study utilized two different interventions designed to reduce occupants' exposures to airborne particles: (1) high efficiency filters in the building's HVAC systems; and (2) thorough cleaning of carpeted floors and fabric-covered chairs with an unusually powerful vacuum cleaner. The study population was the workers on the second and fourth floors of a large office building with mechanical ventilation, air conditioning, and sealed windows. Interventions were implemented on one floor while the occupants on the other floor served as a control group. For the enhanced-filtration intervention, a multiple crossover design was used (a crossover is a repeat of the experiment with the former experimental group as the control group and vice versa). Demographic and health symptom data were collected via an initial questionnaire on the first study week and health symptom data were obtained each week, for eight additional weeks, via weekly questionnaires. A large number of indoor environmental parameters were measured during the study including air temperatures and humidities, carbon dioxide concentrations, particle concentrations, concentrations of several airborne bioaerosols, and concentrations of several microbiologic compounds within the dust sampled from floors and chairs. This report describes the study methods and summarizes the results of selected environmental measurements.
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Given a polynomial-like mapping P acting on a plane domain, one denotes the forward iterates of P under composition by P(sup n). These iterates determine a dynamical system acting on a neighborhood of the Julia set. If one assumes...
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Given a polynomial-like mapping P acting on a plane domain, one denotes the forward iterates of P under composition by P(sup n). These iterates determine a dynamical system acting on a neighborhood of the Julia set. If one assumes the Julia set is connected, one may uniformize the complement of the Julia set by a Riemann mapping r, mapping the complement to the exterior of the unit disk. The forward iterates P(sup n) are conjugated to iterates r (circle) P(sup n) (circle) 1/r, which forms a dynamical system acting on the exterior of the unit disk and which extends to an action on the unit circle. This conjugated dynamical system is expanding along the unit circle, which is a repeller. The chief result of this paper is that such dynamical systems, for a given degree, form part of a Teichmuller space. It is an infinite dimensional complex manifold modeled on a Banach space and it has a Teichmuller's metric which is complete. The Banach space is a space of quadratic differentials and, for a special case, this space is identifiable with certain lacunary series.
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Local formulae are given for the characteristic classes of a quasiconformal manifold using the subspace of exact forms in the Hilbert space of middle dimensional forms. The method applies to combinatorial manifolds and all topolog...
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Local formulae are given for the characteristic classes of a quasiconformal manifold using the subspace of exact forms in the Hilbert space of middle dimensional forms. The method applies to combinatorial manifolds and all topological manifolds except certain ones in dimension four.
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A quantitative technique is illustrated which uses publication statistics from a bibliography of citations in the area of weak interactions to provide a view of trends and patterns in the development of the field during the period...
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A quantitative technique is illustrated which uses publication statistics from a bibliography of citations in the area of weak interactions to provide a view of trends and patterns in the development of the field during the period from 1950 to 1960. An overview is given of what the physicists working in weak interactions during this period were doing as indicated by an analysis of the subjects of their papers. The dominant problems and concerns are discussed. Focus is then turned to the events surrounding the emergence of the tau/theta particle puzzle, the discovery of parity nonconservation, and the resolution offered by the V-A theory. Displaying the data from the citation index in unusual ways highlights dominant issues of the period, especially the close relationship between theory and experiment in the latter half of the decade. 64 refs., 14 figs. (ERA citation 11:028988)
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