A Kinematical Investigation of Some External Wind Tunnel Force Measurement Systems

A discussion on the fundamental concepts associated with wind tunnel forces measurement systems (balances) is presented. Detailed static analyses are performed on the six component pyramidal, six component floating beam, and three component strain gaged strut balances. These static analyses lead to a dimensional uncertainty investigation of the pyramidal and strain gaged strut balances. The critical dimensions for the pyramidal balance are found to be the lengths of the pyramidal links, like platform half-width, and the model attachment strut. No single dimension on the strain gaged strut is more critical than the others. A new method for the classification of wind tunnel force balances is presented. This method uses two defined quantities: the degree of coupling, and a hardware parameter based on the number of areas where tolerances are of a concern. The versatility of the method is demonstrated through a number of classification examples. The following recommendations are made: determine the effects of component deflection on the pyramidal force balance readouts and investigate the uncertainties associated with low strains on the three component strain gaged strut

On-Road Remote Sensing of CO Emissions in the Los Angeles Basin

The University of Denver remote sensor for on-road motor vehicle carbon monoxide emissions was used for eleven days in the Los Angeles Basin in December, 1989. The remote sensor has been incorporated into the 1990 Clean Air Act Amendments as on-road emissions testing . The device measures the CO/CO2 ratio for one-half second behind each vehicle, from which the exhaust %CO is calculated. Vehicles were measured in a mix of many driving modes and speeds ranging from deceleration coming up to a red traffic light through idling in heavy congestion up to accelerations and cruises entering a freeway ramp at highway speeds. The results have been validated by both EPA and CARB blind comparisons. The calculated %CO is analogous to that which would have been measured had the vehicle been equipped with a tailpipe probe. The mass emissions in grams CO per gallon of gasoline used can also be derived. Eight of the days monitored normal urban street driving; three monitored freeway ramps. Over 27,000 valid CO emission measurements were made. When the videotapes had been read and returned to California authorities for matching the license plates, the total number of vehicles both measured and matched with the license plate database was over 16,000. Because of the poor contrast of older California license plates and the sun angles, more plates were readable when the front of the vehicles were imaged. With this arrangement a significant number of vehicles without front plates could not be identified. The license plate matched fleet was 0.15 %CO cleaner (3/4 of year on average newer) than the total fleet. This probably arises because older vehicles have older style plates which are both intrinsically harder to read (lower contrast), and often in poorer condition. Overall for the driving modes and vehicles tested more than fifty percent of the CO was emitted by eleven percent of the vehicles with %CO equal to or greater than five (gross polluters). New vehicles were so clean (gross polluters were less than 1% for the 1989 and 90 model years) that their emissions were almost negligible. The percentage of gross polluters rises from 4% (328 vehicles) of the 83-90 model year vehicles through 17% for the 75-80 model year vehicles to 30% (504 vehicles) of the 1974 and older fleet. If the whole measured fleet could maintain the 1989 and 1990 measured emissions then the total on-road pollution from the 16,000 vehicles measured would decrease more than fivefold. Despite the fact that the new vehicles are on average clean, the dirtiest 20% of the one year old fleet was dirtier than the cleanest 20% of any model years regardless of age. Because old vehicles are not numerous, and most new vehicles are low emitters, most of the carbon monoxide came from emissions of the dirtiest 20% of the vehicles with model years between 1976 and 1988. An analysis of the data indicates that a conservative upper limit of fifteen percent of the measured CO emissions arises from vehicles in either a cold start or an off-cycle acceleration mode. Forty three percent of the fleet of 77 vehicles measured four or more times were always in the clean (\u3c1 %CO) category. These emit 4% of the total CO from all 77 vehicles. One quarter of the fleet of 77 showed emissions consistently between one and five percent CO. These vehicles emitted 18% of the CO An additional 25% of the fleet were over the five percent CO cut point at least twice. These vehicles emitted 70% of the emissions. Only a small fraction (5 vehicles, 7% of the fleet of 77 vehicles) jumped into the high category only once. The emissions variability observed in this data set is similar to the emissions variability observed when vehicles are repetitively subjected to conventional I/M testing. These results imply that an inspection and maintenance program incorporating remote sensing, which targets gross polluters with multiple violations, has the potential to identify a significant fraction of the CO emissions while inconveniencing only a small fraction of the vehicle owners. Our analysis concludes that on-road remote sensing as a component of an I/M program has the advantages of being representative of the on-road emissions of the vehicle in question, being an emissions test which is almost impossible to circumvent, and incorporates a fairness factor such that the more a vehicle is driven, the more frequently it will be tested. When age related factors are eliminated the findings in California are essentially identical to findings from on-road CO studies of large fleets of vehicles in Denver, Chicago and Toronto. Forty-seven vehicles out of a fleet of 387 vehicles registered as diesels show emissions greater than 2%CO. Of these vehicles, thirty-nine are 1975-84 General Motors vehicles. The vehicles are such high emitters that the only sub-fleet found to be dirtier are 1955-1970 vehicles. Three lines of evidence point to the conclusion that more than half of the vehicles listed in this category are not diesel powered and are incorrectly registered thereby avoiding the California Smog-Check program. There were differences in average CO emissions between the sites measured, and to a lesser extent between different days at the same sites. To aid in understanding this phenomenon, all remote sensing data available at the University of Denver from a variety of US cities with altitudes lower than 7,000 ft were analyzed in terms of hourly average CO emissions compared to hourly average fleet age. From this analysis a linear model was developed which demonstrated that almost all of the observed differences could be accounted for by differences in average age. This results because of the previously shown influence of the gross polluters which increases with fleet age. Smaller, load induced average emission increases between an uphill but slow cruise-mode freeway off-ramp and a flat but high speed acceleration on-ramp were discernable after the age differences had been eliminated. The linear model predicts average %CO for all fleets measured in the USA to better than 0.5 %CO with a knowledge of only the average fleet age. The important conclusions are that a few vehicles (gross polluters) emit most of the CO A few vehicles are always measured in the gross polluter category, a few are frequently in that category, and most are never gross polluters. The fraction of gross polluters increases from one in one hundred new vehicles up to one in three old ones. Although new vehicle standards and technology changed from the early seventies to the early eighties, no sharp breaks are observed for the transition model years. The evidence suggests that on-road CO emissions increase linearly with average age of the fleet, and that the linear increase is dominated by the steady increase in the fraction of gross polluters with age. This increase with age appears to be caused in large part by improper (in some cases illegal) maintenance practices

P2Y2 nucleotide receptors mediate inflammatory responses in mouse salivary gland cells

Abstract only availableSjögren's syndrome (SS) is a chronic inflammatory autoimmune disease characterized by destruction of salivary and lacrimal glands leading to xerostomia (dry mouth) and xerophthalmia (dry eyes). Although the mechanisms involved have not been adequately elucidated, the diminished function of exocrine glands in SS is often associated with lymphocytic infiltration of the tissue. Aberrant expression of specific adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1) is also observed in salivary gland with SS, which enable salivary epithelium to interact directly with infiltrating lymphocytes. P2Y2 nucleotide receptor (P2Y2R) is G protein-couple receptor that is activated by extracellular ATP and UTP. P2Y2R expression and activity is up-regulated in response to damage or stress in a variety of tissues, including submandibular glands (SMGs), where it mediates a complex set of cellular responses to injury of disease. Additionally, P2Y2R activation up-regulates VCAM-1 expression in dispersed rat SMG cell culture and human submandibular gland (HSG) cells. Our objective is to investigate weather P2Y2R up-regulation correlates with increased expression of adhesion molecules in SMGs from a mouse model for SS (C57BL/6.NOD-Aec1Aec2) as compared with normal mouse strain (C57BL/6). P2Y2R expression was measured by RT-PCR and adhesion molecules expression was determined by Western blot analysis. Salivary flow was preformed by cannulation of individual glands. We could see that P2Y2R expression and ICAM-1 expression were both up-regulated in the SMGs from a mouse model for SS as compared with normal mouse strain. And salivary flow was decreased in salivary glands from a mouse model for SS. These results suggest that P2Y2R mediate inflammatory responses related to secretory dysfunction in the mouse model for SS. Our ultimate goal would be to translate all this information to the human salivary gland in order to understand SS and to develop new therapies for salivary dysfunction in SS.Gyeongsang National Universit

Unmanned Aerial Systems (UAS) - What are they?

A panel of five aviation experts will discuss Unmanned Aerial Systems (UAS). Particular emphasis will be placed on the rules governing UAS operation. A UAS operational demonstration will be conducted

Laser-Based Propagation of Human iPS and ES Cells Generates Reproducible Cultures with Enhanced Differentiation Potential

Proper maintenance of stem cells is essential for successful utilization of ESCs/iPSCs as tools in developmental and drug discovery studies and in regenerative medicine. Standardization is critical for all future applications of stem cells and necessary to fully understand their potential. This study reports a novel approach for the efficient, consistent expansion of human ESCs and iPSCs using laser sectioning, instead of mechanical devices or enzymes, to divide cultures into defined size clumps for propagation. Laser-mediated propagation maintained the pluripotency, quality, and genetic stability of ESCs/iPSCs and led to enhanced differentiation potential. This approach removes the variability associated with ESC/iPSC propagation, significantly reduces the expertise, labor, and time associated with manual passaging techniques and provides the basis for scalable delivery of standardized ESC/iPSC lines. Adoption of standardized protocols would allow researchers to understand the role of genetics, environment, and/or procedural effects on stem cells and would ensure reproducible production of stem cell cultures for use in clinical/therapeutic applications

The Black Hole Mass of NGC 4151: Comparison of Reverberation Mapping and Stellar Dynamical Measurements

We present a stellar dynamical estimate of the black hole (BH) mass in the Seyfert 1 galaxy, NGC 4151. We analyze ground-based spectroscopy as well as imaging data from the ground and space, and we construct 3-integral axisymmetric models in order to constrain the BH mass and mass-to-light ratio. The dynamical models depend on the assumed inclination of the kinematic symmetry axis of the stellar bulge. In the case where the bulge is assumed to be viewed edge-on, the kinematical data give only an upper limit to the mass of the BH of ~4e7 M_sun (1 sigma). If the bulge kinematic axis is assumed to have the same inclination as the symmetry axis of the large-scale galaxy disk (i.e., 23 degrees relative to the line of sight), a best-fit dynamical mass between 4-5e7 M_sun is obtained. However, because of the poor quality of the fit when the bulge is assumed to be inclined (as determined by the noisiness of the chi^2 surface and its minimum value), and because we lack spectroscopic data that clearly resolves the BH sphere of influence, we consider our measurements to be tentative estimates of the dynamical BH mass. With this preliminary result, NGC 4151 is now among the small sample of galaxies in which the BH mass has been constrained from two independent techniques, and the mass values we find for both bulge inclinations are in reasonable agreement with the recent estimate from reverberation mapping (4.57[+0.57/-0.47]e7 M_sun) published by Bentz et al.Comment: 20 pages, including 11 low-res figures. Accepted for publication in ApJ. High resolution version available upon reques