Development of an Aerodynamic Model and Control Law Design for a High Altitude Airship

2004 ◽  
Author(s):  
Joseph B. Mueller ◽  
Michael A. Paluszek ◽  
Yiyuan Zhao
Keyword(s):  
High Altitude ◽  
Control Law ◽  
Aerodynamic Model ◽  
And Control

Simulation of thermal stress and control measures for rock-filled concrete dam in high-altitude and cold regions

2021 ◽  
Vol 230 ◽  
pp. 111721
Author(s):  
Yuxiang Zhang ◽  
Jianwen Pan ◽  
Xinjian Sun ◽  
Jijun Feng ◽  
Dengqiang Sheng ◽  
...  
Keyword(s):  
Thermal Stress ◽  
High Altitude ◽  
Control Measures ◽  
Concrete Dam ◽  
Cold Regions ◽  
And Control

scholarly journals Pollination of two species of Vellozia (Velloziaceae) from high-altitude quartzitic grasslands, Brazil

2007 ◽  
Vol 21 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Claudia Maria Jacobi ◽  
Mário César Laboissiérè del Sarto
Keyword(s):  
High Altitude ◽  
Pollen Limitation ◽  
Cross Pollination ◽  
Se Brazil ◽  
Self Compatibility ◽  
Leaf Cutting ◽  
Pollen Theft ◽  
Floral Displays ◽  
Facultative Xenogamy ◽  
And Control

The pollinators and breeding system of two species of Vellozia (Velloziaceae) from high-altitude quartzitic grasslands in SE Brazil were studied. Vellozia leptopetala is shrubby and grows solely on rocky outcrops, V. epidendroides is herbaceous and grows on stony soils. Both bear solitary, hermaphrodite flowers, and have massive, short-lasting annual blooms. We evaluated the level of self-compatibility and need for pollinators of 50 plants of each species and 20-60 flowers per treatment: hand self- and cross-pollination, spontaneous pollination, agamospermy and control. The behavior of floral visitors on flowers and within plants was recorded. Both species are mostly self-incompatible, but produce a small number of seeds by self-fertilization. The pollen-ovule ratio suggests facultative xenogamy. They were visited primarily by bees, of which the most important pollinators were two leaf-cutting bees (Megachile spp.). Vellozia leptopetala was also pollinated by a territorial hummingbird. Low natural seed production compared to cross-pollination seed numbers suggests that pollen limitation is the main cause of low seed set. This was attributed to the combined effect of five mechanisms: selfing prior to anthesis, enhanced geitonogamy as a result of large floral displays, low number of visits per flower for the same reason, pollen theft by many insect species, and, in V. leptopetala, delivery of mixed pollen loads on the stigma as a consequence of hummingbird promiscuity.

Analysis of emissions from various driving cycles based on real driving measurements obtained in a high-altitude city

2020 ◽  
Vol 234 (6) ◽  
pp. 1563-1571 ◽  
Author(s):  
Meng Lyu ◽  
Xiaofeng Bao ◽  
Yunjing Wang ◽  
Ronald Matthews
Keyword(s):  
High Altitude ◽  
Real World ◽  
Vehicle Emissions ◽  
Control Strategies ◽  
Driving Cycle ◽  
Specific Power ◽  
Test Cycle ◽  
Light Duty ◽  
And Control ◽  
Light Duty Vehicles

Vehicle emissions standards and regulations remain weak in high-altitude regions. In this study, vehicle emissions from both the New European Driving Cycle and the Worldwide harmonized Light-duty driving Test Cycle were analyzed by employing on-road test data collected from typical roads in a high-altitude city. On-road measurements were conducted on five light-duty vehicles using a portable emissions measurement system. The certification cycle parameters were synthesized from real-world driving data using the vehicle specific power methodology. The analysis revealed that under real-world driving conditions, all emissions were generally higher than the estimated values for both the New European Driving Cycle and Worldwide harmonized Light-duty driving Test Cycle. Concerning emissions standards, more CO, NOx, and hydrocarbons were emitted by China 3 vehicles than by China 4 vehicles, whereas the CO2 emissions exhibited interesting trends with vehicle displacement and emissions standards. These results have potential implications for policymakers in regard to vehicle emissions management and control strategies aimed at emissions reduction, fleet inspection, and maintenance programs.

Fuel Systems For Supersonic Engines

1958 ◽  
Vol 62 (573) ◽  
pp. 654-658
Author(s):  
E. A. Simonis
Keyword(s):  
Combustion Chamber ◽  
High Altitude ◽  
Control Problems ◽  
Fuel System ◽  
Complex Control ◽  
Supersonic Aircraft ◽  
Engine Combustion ◽  
Main Engine ◽  
And Control

The advent of the high altitude supersonic aircraft has brought in its train a whole host of complex control problems. As far as the engine manufacture is concerned, these are perhaps best indicated in the diagrammatic layout shown in Fig. 1It is not my intention however, to go into the question of multiplicity of controls and their proper co-ordination, nor will I venture into the abstruse province of stability. I should like instead to concentrate on the fuel system itself, i.e. the supply and control of fuel to the main engine combustion chamber.

scholarly journals A Sub-100 mg Electromagnetically Driven Insect-inspired Flapping-wing Micro Robot Capable of Liftoff and Control Torques Modulation

2020 ◽  
Vol 17 (6) ◽  
pp. 1085-1095
Author(s):  
Chenyang Wang ◽  
Weiping Zhang ◽  
Yang Zou ◽  
Ran Meng ◽  
Jiaxin Zhao ◽  
...  
Keyword(s):  
Input Voltage ◽  
Flapping Wing ◽  
Total Weight ◽  
Voltage Amplitude ◽  
Torque Measurement ◽  
Electromagnetic Actuators ◽  
Aerodynamic Model ◽  
Micro Robot ◽  
The Mean ◽  
And Control

AbstractInspired by the unique, agile and efficient flapping flight of insects, we present a novel sub-100 mg, electromagnetically driven, tailless, flapping-wing micro robot. This robot utilizes two optimized electromagnetic actuators placed back to back to drive two wings separately, then kinematics of each wing can be independently controlled, which gives the robot the ability to generate all three control torques of pitch, roll and yaw for steering. To quantify the performance of the robot, a simplified aerodynamic model is used to estimate the generated lift and torques, and two customized test platforms for lift and torque measurement are built for this robot. The mean lift generated by the robot is measured to be proportional to the square of the input voltage amplitude. The three control torques are measured to be respectively proportional to three decoupled parameters of the control voltages, therefore the modulation of three control torques for the robot is independent, which is helpful for the further controlled flight. All these measured results fit well with the calculated results of the aerodynamic model. Furthermore, with a total weight of 96 mg and a wingspan of 3.5 cm, this robot can generate sufficient lift to take off.

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