4,128 research outputs found
Fluid-pressure meter can be calibrated without removal from flow line
The construction of a fluid pressure meter with two inlet ports, flexible diaphragms and a pressure-responsive transducer is described. One port can be connected to the line and the other to a source of standard pressures for calibration
Solar residential heating and cooling system
System has been placed in operation to verify technical feasibility of using solar energy to provide residential heating and cooling. Complete system analysis was performed to provide design information
Minimum noise impact aircraft trajectories
Numerical optimization is used to compute the optimum flight paths, based upon a parametric form that implicitly includes some of the problem restrictions. The other constraints are formulated as penalties in the cost function. Various aircraft on multiple trajectores (landing and takeoff) can be considered. The modular design employed allows for the substitution of alternate models of the population distribution, aircraft noise, flight paths, and annoyance, or for the addition of other features (e.g., fuel consumption) in the cost function. A reduction in the required amount of searching over local minima was achieved through use of the presence of statistical lateral dispersion in the flight paths
Solar residential heating and cooling system development test program
A solar heating and cooling system is described, which was installed in a simulated home at Marshall Space Flight Center. Performance data are provided for the checkout and initial operational phase for key subsystems and for the total system. Valuable information was obtained with regard to operation of a solar cooling system during the first summer of operation. Areas where improvements and modifications are required to optimize such a system are discussed
Truckload freight transportation utilizing relay points to improve the driving job
We propose a relay point based approach on a highway transportation network to obtain robust solutions for the truck driver turnover and driver retention problem. We exploit the characteristics of the driver routing problem and truckload freight moved over a highway transportation network and introduce a new approach to route drivers over shorter distances and to move trailers continuously while holistically considering important performance measures as related to the truck driver, transportation carrier, and customer. The amount of time drivers spend driving and the time spent at home are exploited to determine a balance between driver home time and driver pay. A mathematical program is introduced to determine where relay points should be more optimally located to exchange equipment, perform equipment maintenance, access resting facilities, etc. while considering important costs related to transporting truckload freight. The intention is to propose a method to improve the truckload driving job but not at the expense of the transportation carrier and customer. We discuss some of the desirable characteristics of this approach and also investigate the sensitivity of the solutions via a numerical experiment
Evaluation of HCFC AK 225 Alternatives for Precision Cleaning and Verification
Maintaining qualified cleaning and verification processes are essential in an production environment. Environmental regulations have and are continuing to impact cleaning and verification processing in component and large structures, both at the Michoud Assembly Facility and component suppliers. The goal of the effort was to assure that the cleaning and verification proceeds unimpeded and that qualified, environmentally compliant material and process replacements are implemented and perform to specifications. The approach consisted of (1) selection of a Supersonic Gas-Liquid Cleaning System; (2) selection and evaluation of three cleaning and verification solvents as candidate alternatives to HCFC 225 (Vertrel 423 (HCFC), Vertrel MCA (HFC/1,2-Dichloroethylene), and HFE 7100DE (HFE/1,2 Dichloroethylene)); and evaluation of an analytical instrumental post cleaning verification technique. This document is presented in viewgraph format
The Importance of Mass Culture for Democratization
In the last thirty years, the importance of political culture in political science has risen, declined, and has risen again. Although the theories of political culture have been strengthened and refined in this process, modern culture theorists have yet to empirically demonstrate culture\u27s ability to be used as an independent variable or to make causal claims using culture. This paper makes an attempt to solve these empirical deficiencies in cultural theory by setting up what Brian Barry calls a critical test. Using the former USSR and the post-communist countries in Eastern Europe, I will test two hypotheses. First, mass values and not elite bargaining caused the transition from communism to democracy in these countries, and second, these mass values were not a result of rational self interest or elite manipulation, but they formed through the interaction of different sub-cultures. The first hypothesis will be tested by a quantitative analysis of the relationship between mass political protest and democratization, and to be considered valid, the peak level of democratization should follow the peak of mass political protest relatively closely. The second hypothesis will be tested using a cross-tab between culture and indicators of democratic values from the World Values Survey. To be considered valid, there should be a relatively strong significant correlation with individualist and egalitarian cultures displaying more democratic values than fatalist or hierarch culture. From the data gathered, these hypotheses seem to be valid; however, economic variables seem to play a minimal role as well
Efficient Retrieval and Ranking of Undesired Package Cycles in Large Software Systems
International audienceMany design guidelines state that a software system architecture should avoid cycles between its packages. Yet such cycles appear again and again in many programs. We believe that the existing approaches for cycle detection are too coarse to assist the developers to remove cycles from their programs. In this paper, we describe an efficient algorithm that performs a fine-grained analysis of the cycles among the packages of an application. In addition, we define a metric to rank cycles by their level of undesirability, prioritizing the cycles that seems the more undesired by the developers. Our approach is validated on two large and mature software systems in Java and Smalltalk
The Fate of Sulfamethazine in Sodium-Hypochlorite-Treated Drinking Water: Monitoring by LC-MSN-IT-TOF
Pharmaceutical compounds represent a rapidly emerging class of environmental contaminants. Such compounds were recently classified by the U.S. Geological Survey, including several antibiotics. An LC-MS/MS screening method for the top five antibiotics in drinking water was developed and validated using a Shimadzu LC-MS-IT-TOF. The separation was performed using a Waters Acquity UPLC BEH C18 column with a gradient elution. Sulfamethazine was exposed to conditions intended to mimic drinking water chlorination, and samples were collected and quenched with excess sodium sulfite. Kinetics of sulfamethazine degradation was followed as well as the formation of the major chlorinated byproduct (m/z 313). For the screening method, all five antibiotic peaks were baseline resolved within 5 minutes. Additionally, precision and accuracy of the screening method were less than 15%. Degradation of sulfamethazine upon exposure to drinking water chlorination occurred by first order kinetics with a half-life of 5.3 × 10(4) min (approximately 37 days) with measurements starting 5 minutes after chlorination. Likewise, the formation of the major chlorinated product occurred by first order kinetics with a rate constant of 2.0 × 10(-2). The proposed identification of the chlorinated product was 4-amino-(5-chloro-4,6-dimethyl-2-pyrimidinyl)-benzenesulfonamide (C12H13N4O2SCl) using MS (n) spectra and databases searches of SciFinder and ChemSpider
- …