Results 71 to 80 of about 296,267 (293)

Gravity waves in the middle atmosphere: Recent progress and needed studies [PDF]

open access: yes, 1986
The recent recognition of the important role played by gravity waves in the large-scale circulation and thermal structure of the mesosphere and lower thermosphere has stimulated considerable research on their properties and their middle atmosphere ...
Fritts, D. C.
core   +1 more source

Gravity Waves from Quantum Stress Tensor Fluctuations in Inflation

open access: yes, 2011
We consider the effects of the quantum stress tensor fluctuations of a conformal field in generating gravity waves in inflationary models. We find a non-scale invariant, non-Gaussian contribution which depends upon the total expansion factor between an ...
A. A. Starobinsky   +7 more
core   +1 more source

Fully 3D‐Printed Wave‐Wound Electromagnetic Motors

open access: yesAdvanced Materials Technologies, EarlyView.
This work presents the first fully 3D‐printed wave‐wound electromagnetic motors, which are created using conductive nanoparticle inks, carbon‐filled nylon polymers, and surface mount components. These motors can achieve a stall torque of 7.62N·mmA−1$7.62 \nobreakspace N{\cdot }mm A^{-1}$ and efficiency of 28.2 %, which approaches the performance of ...
Joseph Schwalbe   +4 more
wiley   +1 more source

Magnetic Droplet Manipulation on Open Surfaces

open access: yesAdvanced Materials Technologies, EarlyView.
Recent advances in the manipulation of magnetic droplets demonstrate various manipulations on open surfaces, including transport, splitting, merging, and force‐controlled motion, enabled by magnetic particles and external fields. ABSTRACT Manipulation of liquids on a smaller scale enables applications in various fields, particularly diagnostics and ...
Robab Jahangir, Vahid Nasirimarekani
wiley   +1 more source

Multiobjective Codesign Optimization of a Planar Pneumatic Artificial Muscle‐Based Snake‐Like Robot for Enhanced Agility and Energy Efficiency

open access: yesAdvanced Robotics Research, EarlyView.
A codesign multiobjective optimization framework was developed to enhance the morphology and controller of a snake‐like robot driven by artificial muscles. It improved planar locomotion, agility, and power efficiency. The approach optimized link geometry and controller gains, revealing that shorter muscles near joints and longer linkages maximize ...
Ayla Valles, Mahdi Haghshenas‐Jaryani
wiley   +1 more source

Chiral Primordial Gravitational Waves from a Lifshitz Point

open access: yes, 2009
We study primordial gravitational waves produced during inflation in quantum gravity at a Lifshitz point proposed by Ho${\rm\check{r}}$ava. Assuming power-counting renormalizability, foliation preserving diffeomorphism invariance, and the condition of ...
A. A. Starobinsky   +2 more
core   +1 more source

Soft Robotic Snake with Tunable Undulatory Gait for Efficient Underwater Locomotion

open access: yesAdvanced Robotics Research, EarlyView.
This study designs an underwater soft snake robot using 3D‐printed soft actuators, controlled by specific signals to generate sinusoidal undulation. Results show a positive correlation between speed and swing amplitude, with optimal performance at 2/3π phase offset, PLA tail, 1.2 voltage growth rate, and 6s undulation period achieving a maximum speed ...
Huichen Ma, Junjie Zhou, Raye Yeow
wiley   +1 more source

Hard‐Magnetic Soft Millirobots in Underactuated Systems

open access: yesAdvanced Robotics Research, EarlyView.
This review provides a comprehensive overview of hard‐magnetic soft millirobots in underactuated systems. It examines key advances in structural design, physics‐informed modeling, and control strategies, while highlighting the interplay among these domains.
Qiong Wang   +4 more
wiley   +1 more source

Nonlinear acoustic–gravity waves

open access: yesJournal of Plasma Physics, 2009
AbstractPrevious results on nonlinear acoustic–gravity waves are reconsidered. It turns out that the mathematical techniques used are somewhat similar to those already adopted by the plasma physics community. Consequently, a future interaction between physicists in different fields, e.g. in meteorology and plasma physics, can be very fruitful.
Stenflo, L., Shukla, P.K.
openaire   +4 more sources

Nonlocomotory Robotic Strategies for Dynamic Rotation Control in Terrestrial Robots: A Review

open access: yesAdvanced Robotics Research, EarlyView.
Terrestrial robots increasingly require rapid body rotation to maintain stability and agility in complex environments. This review shows nonlocomotory rotational control strategies that operate without ground contact, including reaction wheels, tails, bars, limbs, and thrusters.
Y. Liang   +14 more
wiley   +1 more source

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