Добірка наукової літератури з теми "Untethered Balloon"

Soft unmanned flying objects have been developed to improve communication in areas where natural disasters occur. This article investigates the design, modeling, and control of an unmanned flying robot, different from classic flying robots which are based on electric motors, robots driven by soft actuators that have advantages of low noise, deformable property, and fast response. Untethered system based on dielectric elastomer actuators can be controlled to move, theory and experiments are presented to show the movement accompanied by large voltage-triggered deformation. We connect a dielectric elastomer balloon-shaped shell to an inelastic chamber which has larger volume and apply voltage to trigger one-layer or two-layer VHB membrane without causing electrical breakdown. The results show that buoyancy force in the air for helium balloon system is inversely proportional to the altitude when the flight system goes up. Compared with single-layer balloon shell, we also generalize the concept of multi-layer soft actuators that offer larger deformation. The larger the original volume of the untethered system is, the more mass can be controlled at the actuated state. Voltage-triggered controllable motion is appreciating with our designed structure.

Nematic elastomer balloons with inflation-induced axial contraction and shear/torsion effect can be used as actuators for soft robots, artificial muscles, and biomedical instruments. The nematic elastomer can also generate drastic shape changes under illumination, and thus light can be utilized to activate the deformation of nematic elastomer balloons with huge advantages of being accurate, fast, untethered, and environmentally sustainable without chemical byproducts. To explore light-activated deformation behaviors of the balloon, a phenomenological relationship between light intensity and material parameters describing polymer backbone anisotropy is proposed from experiments, and a theoretical model of an optically-responsive nematic elastomer balloon is established based on the nematic elastomer theory. Various light-activated elongation/shortening and twisting behaviors in the cases of free-standing and axial-loading are presented and their mechanisms are elucidated. The light intensity and initial mesogen angle have great influences on the light-activated deformations including the radius, length, shearing angle and mesogen angle. Light can be easily controlled to trigger rich deformation processes, including elongation/shortening and torsion. The results of this paper are expected to promote the understanding of the light-activated deformation behaviors of the nematic elastomer balloon, and the applications in light-activated actuators and machines.

The efforts to attract students to precalculus, trigonometry, and calculus classes became more successful when projects-based classes were offered. Data collection from an untethered hot air balloon flight for calculus students was planned to maximize enrollment. The data were analyzed numerically, graphically, and algebraically. The project made calculus more meaningful and memorable for students.

The efforts to attract students to precalculus, trigonometry, and calculus classes became more successful when projects-based classes were offered. Data collection from an untethered hot air balloon flight for calculus students was planned to maximize enrollment. The data were analyzed numerically, graphically, and algebraically. The project made calculus more meaningful and memorable for students.

This thesis describes the development and field testing of two in situ cloud observation instruments based on the principle of digital holography. These instruments have been designed to be both low cost and light weight, as suited for observations over wide areas as part of a network of sensors, and for vertical profiling of clouds from an untethered weather balloon. These capabilities are believed, by this author, to be unique to the instruments presented in this work and are intended to address the distinct lack of in situ cloud microphysical observations that are required for improving the understanding of cloud processes, calibration of climate and weather models, and validation of remote sensing observation methods. A major challenge in the development of holographic instruments relates to their autonomous operation under field conditions. Methods are presented to overcome these issues, and aspects of the design process that allow significant reductions in cost and weight, as compared with standard instruments, are described. Automated analysis methods are an essential aspect of a holographic system, particularly for those presented in this work which are intended to be deployed under conditions in which they may be lost. Two automated analysis methods are presented in this work and are tested and optimised using field observations as well as a numerical model of a holographic system that was developed in this work. One of the developed holographic instruments was deployed in a multi-month field campaign in the Australian Snowy Mountains alongside a range of standard instruments. An in-depth analysis of observations from all instruments for a range of different atmospheric events is undertaken, with a particular focus on assessing the performance of the developed holographic instrument. The holographic observations were found to be consistent with those of the other instruments within the overlapping resolution ranges that each were sensitive to. The potential for this instrument to classify atmospheric events was demonstrated using case studies, and holographic observations revealed biases in the microphysical outputs of a reanalysis model. A world-first untethered balloon launch of a holographic microscope into clouds is described. Multiple bands of cloud were identified and the feasibility of this approach was demonstrated. Insights are presented relating to the microphysical structure of a post-drizzling warm stratus cloud, as well as cold clouds at higher altitudes. Microphysical retrievals from an imaging satellite are evaluated using the in situ observations from this launch. The satellite retrievals were found to exhibit distinct biases, consistent with those identified in prior evaluation campaigns.
Thesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2022