Confined Spaces in [n]Cyclo‐2,7‐pyrenylenes

Animal flight represents a great challenge and model for biomimetic design efforts. Powered flight at low speeds requires not only appropriate lifting surfaces (wings) and actuator (engine), but also an advanced sensory control system to allow maneuvering in confined spaces, and take-off and landing. Millions of years of evolutionary tinkering has resulted in modern birds and bats, which are achieve controlled maneuvering flight as well as hovering and cruising flight with trans-continental non-stop migratory flights enduring several days in some bird species. Unsteady aerodynamic mechanisms allows for hovering and slow flight in insects, birds and bats, such as for example the delayed stall with a leading edge vortex used to enhance lift at slows speeds. By studying animal flight with the aim of mimicking key adaptations allowing flight as found in animals, engineers will be able to design micro air vehicles of similar capacities.

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Intelligent Exploration and Autonomous Navigation in Confined Spaces

2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) ◽

10.1109/iros45743.2020.9341525 ◽

2020 ◽

Author(s):

Aliakbar Akbari ◽

Puneet S Chhabra ◽

Ujjar Bhandari ◽

Sara Bernardini

Keyword(s):

Autonomous Navigation ◽

Confined Spaces

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A Magneto-Active Elastomer Crawler with Peristaltic and Caterpillar Locomotion Patterns

Actuators ◽

10.3390/act10040074 ◽

2021 ◽

Vol 10 (4) ◽

pp. 74

Author(s):

Tsam Lung You ◽

Hemma Philamore ◽

Fumitoshi Matsuno

Keyword(s):

Magnetic Field ◽

Experimental Data ◽

External Magnetic Field ◽

Mathematical Models ◽

Confined Spaces ◽

Low Mass ◽

Structural Simplicity

In this work we present a soft crawler fabricated using a magneto-active elastomer. The crawler is controlled by an external magnetic field to produce two locomotion patterns: peristaltic and caterpillar crawling. Due to its structural simplicity, low mass, wirelessly controlled actuation and compliant body the design of this crawler has the potential to address the key challenges faced by existing crawling robots. Experimental data were gathered to evaluate the performance of the crawler locomotion in a pipe. The results validated the mathematical models proposed to estimate the distance traveled by the crawler. The crawler shows potential for use in exploration of confined spaces.

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Effect of Mechanical Ventilation on Accidental Hydrogen Releases—Large-Scale Experiments

Energies ◽

10.3390/en14113008 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3008

Author(s):

Agnieszka W. Lach ◽

André V. Gaathaug

Keyword(s):

Mechanical Ventilation ◽

Mass Flow ◽

Large Scale ◽

Ventilation System ◽

Hydrogen Gas ◽

Forced Ventilation ◽

British Standard ◽

Confined Spaces ◽

Series Of Experiments ◽

Rate Limit

This paper presents a series of experiments on the effectiveness of existing mechanical ventilation systems during accidental hydrogen releases in confined spaces, such as underground garages. The purpose was to find the mass flow rate limit, hence the TPRD diameter limit, that will not require a change in the ventilation system. The experiments were performed in a 40 ft ISO container in Norway, and hydrogen gas was used in all experiments. The forced ventilation system was installed with a standard 315 mm diameter outlet. The ventilation parameters during the investigation were British Standard with 10 ACH and British Standard with 6 ACH. The hydrogen releases were obtained through 0.5 mm and 1 mm nozzles from different hydrogen reservoir pressures. Both types of mass flow, constant and blowdown, were included in the experimental matrix. The analysis of the hydrogen concentration of the created hydrogen cloud in the container shows the influence of the forced ventilation on hydrogen releases, together with TPRD diameter and reservoir pressure. The generated experimental data will be used to validate a CFD model in the next step.

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