Low-cost device for retrieval of moorings deployed with underwater remote release systems

2018 ◽  
Vol 69 (3) ◽  
pp. 473 ◽  
Author(s):  
D. A. Crook ◽  
B. J. Adair ◽  
L. J. Hetherington
Keyword(s):  
Low Cost ◽  
Northern Territory ◽  
Field Conditions ◽  
Aquatic Environments ◽  
Underwater Acoustic ◽  
Current Limitation ◽  
Oceanographic Research ◽  
A Current ◽  
Basic Equipment

Underwater acoustic and timed-release systems are commonly deployed with sensors and other equipment for ecological and oceanographic research in aquatic environments. These systems allow equipment deployed at depth to be remotely released from their moorings for retrieval. However, a current limitation is that most systems do not incorporate mechanisms for retrieval of the mooring anchor and attachments (e.g. shackles, cable). Herein we provide a detailed description and evaluation of a ‘retrieval pod’ that can be attached directly to remotely released underwater devices to facilitate mooring retrieval. The system was tested using acoustic release telemetry receivers under field conditions in a large estuary in the Northern Territory, Australia. Six receivers fitted with pods were retrieved from the field after two consecutive 6-month deployments (12 retrievals in total) with no failed mooring retrievals. Although our tests were confined to shallow depths (<8m), it should be straightforward to modify the system for use in deeper water by increasing the spool capacity. The retrieval pods are reusable, require minimal construction skills and can be assembled from basic equipment available at most hardware or boating stores, making them a convenient and low-cost option for the retrieval of moorings deployed with remote release systems.

scholarly journals Robust Silent Localization of Underwater Acoustic Sensor Network Using Mobile Anchor(s)

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 727
Author(s):  
Rahul Mourya ◽  
Mauro Dragone ◽  
Yvan Petillot
Keyword(s):  
Channel Model ◽  
Low Cost ◽  
Sensor Nodes ◽  
Noise Model ◽  
Robust Estimator ◽  
Acoustic Sensor ◽  
Underwater Acoustic ◽  
Acoustic Channel ◽  
Localization Scheme ◽  
Mobile Anchor

Underwater acoustic sensor networks (UWASNs) can revolutionize the subsea domain by enabling low-cost monitoring of subsea assets and the marine environment. Accurate localization of the UWASNs is essential for these applications. In general, range-based localization techniques are preferred for their high accuracy in estimated locations. However, they can be severely affected by variable sound speed, multipath spreading, and other effects of the acoustic channel. In addition, an inefficient localization scheme can consume a significant amount of energy, reducing the effective life of the battery-powered sensor nodes. In this paper, we propose robust, efficient, and practically implementable localization schemes for static UWASNs. The proposed schemes are based on the Time-Difference-of-Arrival (TDoA) measurements and the nodes are localized passively, i.e., by just listening to beacon signals from multiple anchors, thus saving both the channel bandwidth and energy. The robustness in location estimates is achieved by considering an appropriate statistical noise model based on a plausible acoustic channel model and certain practical assumptions. To overcome the practical challenges of deploying and maintaining multiple permanent anchors for TDoA measurements, we propose practical schemes of using a single or multiple surface vehicles as virtual anchors. The robustness of localization is evaluated by simulations under realistic settings. By combining a mobile anchor(s) scheme with a robust estimator, this paper presents a complete package of efficient, robust, and practically usable localization schemes for low-cost UWASNs.

scholarly journals Personal Protective Equipment used for Infection Control in Dental Practices

2015 ◽  
Vol 3 (1) ◽  
pp. 10-12 ◽  
Author(s):  
AP Pandit ◽  
Neha Bhagatkar ◽  
Mallika Ramachandran
Keyword(s):  
Infection Control ◽  
Personal Protective Equipment ◽  
Low Cost ◽  
Protective Equipment ◽  
Dental Equipment ◽  
Dental Practices ◽  
A Current ◽  
Dental Professionals ◽  
Total Market ◽  
Dental Products

ABSTRACT The potential size of India's dental market is vast and is expected to become one of the largest single country markets for overseas dental products and materials. The total market for the dental equipment and materials is estimated to be around US$ 90 million annually. There are more than 1, 80,000 dental professionals in India, 297 dental institutes and over 5,000 dental laboratories. Thus, there is a huge potential for the market of personal protective equipment (PPE) used for infection control in dentistry. India's market for dental products is extremely dynamic, with a current estimated growth rate of between 25 and 30%. Overall, the dental market is expected to grow by 20%.1 The personal protective equipment used in the practice of dentistry in India. Since dentistry is predominantly a surgical discipline, it leads to exposure to the pathogenic microorganisms harbored in blood, body fluids and other potentially infectious material. Thus, the use of adequate and good quality PPE is imperative for infection control in dental practice. With the growing potential of India's dental market, the growth of the market for PPE is inevitable. But, it is equally important to raise the awareness among dental community about good quality products adhering to required standards to prevent the usage of low-cost, uncertified and sub-standard products that decrease the safety levels of personnel. The present study is conducted with a view to observe the personal protective equipment used for infection control in dental practices. How to cite this article Pandit AP, Bhagatkar N, Ramachandran M. Personal Protective Equipment used for Infection Control in Dental Practices. Int J Res Foundation Hosp Healthc Adm 2015;3(1):10-12.

scholarly journals Data Gathering from a Multimodal Dense Underwater Acoustic Sensor Network Deployed in Shallow Fresh Water Scenarios

2019 ◽  
Vol 8 (4) ◽  
pp. 55 ◽  
Author(s):  
Alberto Signori ◽  
Filippo Campagnaro ◽  
Fabian Steinmetz ◽  
Bernd-Christian Renner ◽  
Michele Zorzi
Keyword(s):  
Data Collection ◽  
Low Cost ◽  
World Ocean ◽  
Environmental Data ◽  
Sensor Nodes ◽  
Real Field ◽  
Acoustic Sensor ◽  
Adaptive Mechanism ◽  
Underwater Acoustic ◽  
Inspection Service

The Robotic Vessels as-a-Service (RoboVaaS) project intends to exploit the most advanced communication and marine vehicle technologies to revolutionize shipping and near-shore operations, offering on-demand and cost-effective robotic-aided services. In particular, the RoboVaaS vision includes a ship hull inspection service, a quay walls inspection service, an antigrounding service, and an environmental and bathymetry data collection service. In this paper, we present a study of the underwater environmental data collection service, performed by a low-cost autonomous vehicle equipped with both a commercial modem and a very low-cost acoustic modem prototype, the smartPORT Acoustic Underwater Modem (AHOI). The vehicle mules the data from a network of low cost submerged acoustic sensor nodes to a surface sink. To this end, an underwater acoustic network composed by both static and moving nodes has been implemented and simulated with the DESERT Underwater Framework, where the performance of the AHOI modem has been mapped in the form of lookup tables. The performance of the AHOI modem has been measured near the Port of Hamburg, where the RoboVaaS concept will be demonstrated with a real field evaluation. The transmission with the commercial modem, instead, has been simulated with the Bellhop ray tracer thanks to the World Ocean Simulation System (WOSS), by considering both the bathymetry and the sound speed profile of the Port of Hamburg. The set up of the polling-based MAC protocol parameters, such as the maximum backoff time of the sensor nodes, appears to be crucial for the network performance, in particular for the low-cost low-rate modems. In this work, to tune the maximum backoff time during the data collection mission, an adaptive mechanism has been implemented. Specifically, the maximum backoff time is updated based on the network density. This adaptive mechanism results in an 8% improvement of the network throughput.

scholarly journals Autonomous Deployment of Underwater Acoustic Monitoring Devices Using an Unmanned Aerial Vehicle: The Flying Hydrophone

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6064
Author(s):  
Daniel Babatunde ◽  
Simon Pomeroy ◽  
Paul Lepper ◽  
Ben Clark ◽  
Rebecca Walker
Keyword(s):  
Autonomous Navigation ◽  
Marine Mammals ◽  
Fourier Transforms ◽  
Low Cost ◽  
Acoustic Monitoring ◽  
Automatic Data ◽  
Underwater Acoustic ◽  
Planning And Control ◽  
The United Kingdom ◽  
And Control

Unmanned aerial vehicles (UAV) are increasingly becoming a popular tool in the observation and study of marine mammals. However, the potential capabilities of these vehicles regarding autonomous operations are not being fully exploited for passive underwater acoustic monitoring in marine mammal research. This article presents results from the development of a UAV system equipped with an underwater acoustic recorder aimed at assisting with the monitoring of harbour porpoises in Special Areas of Conservation in the United Kingdom. The UAV is capable of autonomous navigation, persistent landing, take-off and automatic data acquisition at specified waypoints. The system architecture that enables autonomous UAV flight including waypoint planning and control is described. A bespoke lightweight underwater acoustic recorder (named the PorpDAQ) capable of transmitting the results of fast Fourier transforms (FFT) applied to incoming signals from a hydrophone was also designed. The system’s operation is successfully validated with a combination of outdoor experiments and indoor simulations demonstrating different UAVs capable of autonomously navigating and landing at specific waypoints while recording data in an indoor tank. Results from the recorder suggest that lightweight, relatively low-cost systems can be used in place of heavier more expensive alternatives.

scholarly journals A Ni(OH)2 nanopetals network for high-performance supercapacitors synthesized by immersing Ni nanofoam in water

2019 ◽  
Vol 10 ◽  
pp. 281-293 ◽  
Author(s):  
Donghui Zheng ◽  
Man Li ◽  
Yongyan Li ◽  
Chunling Qin ◽  
Yichao Wang ◽  
...  
Keyword(s):  
Power Density ◽  
Current Density ◽  
High Performance ◽  
Low Cost ◽  
Electrode Reaction ◽  
Commercial Application ◽  
Ion Diffusion ◽  
Symmetric Supercapacitor ◽  
Red Led ◽  
A Current

Developing a facile and environmentally friendly approach to the synthesis of nanostructured Ni(OH)2 electrodes for high-performance supercapacitor applications is a great challenge. In this work, we report an extremely simple route to prepare a Ni(OH)2 nanopetals network by immersing Ni nanofoam in water. A binder-free composite electrode, consisting of Ni(OH)2 nanopetals network, Ni nanofoam interlayer and Ni-based metallic glass matrix (Ni(OH)2/Ni-NF/MG) with sandwich structure and good flexibility, was designed and finally achieved. Microstructure and morphology of the Ni(OH)2 nanopetals were characterized. It is found that the Ni(OH)2 nanopetals interweave with each other and grow vertically on the surface of Ni nanofoam to form an “ion reservoir”, which facilitates the ion diffusion in the electrode reaction. Electrochemical measurements show that the Ni(OH)2/Ni-NF/MG electrode, after immersion in water for seven days, reveals a high volumetric capacitance of 966.4 F/cm3 at a current density of 0.5 A/cm3. The electrode immersed for five days exhibits an excellent cycling stability (83.7% of the initial capacity after 3000 cycles at a current density of 1 A/cm3). Furthermore, symmetric supercapacitor (SC) devices were assembled using ribbons immersed for seven days and showed a maximum volumetric energy density of ca. 32.7 mWh/cm3 at a power density of 0.8 W/cm3, and of 13.7 mWh/cm3 when the power density was increased to 2 W/cm3. The fully charged SC devices could light up a red LED. The work provides a new idea for the synthesis of nanostructured Ni(OH)2 by a simple approach and ultra-low cost, which largely extends the prospect of commercial application in flexible or wearable devices.

Fabricaton Ofactive Devices and Logic Gates on Fibers

2003 ◽  
Vol 769 ◽  
Author(s):  
YongWoo Choi ◽  
Ioannis Kymissis ◽  
Annie Wang ◽  
Akintunde I. Akinwande
Keyword(s):  
Threshold Voltage ◽  
Electronic Structures ◽  
Low Cost ◽  
Logic Gates ◽  
Wearable Electronics ◽  
Drain Voltage ◽  
Large Area ◽  
Active Devices ◽  
P Type ◽  
A Current

AbstractTextiles are a suitable substrate for large area, flexible and wearable electronics because of their excellent flexibility, mechanical properties and low cost manufacturability. The ability to fabricate active devices on fiber is a key step for achieving large area and flexible electronic structures. We fabricated transistors and inverters with a-Si film and pentacene film on Kapton film and cut them into fibers. The a-Si TFT showed a threshold voltage of 8.5 V and on/off ratio of 103 at a drain voltage of 10 V. These are similar to the characteristics of a TFT fabricated on a glass substrate at the same time. The maximum gain of the inverter with an enhancement n-type load was 6.45 at a drain voltage of 10 V. The pentacene OTFT showed a threshold voltage of -8 V and on/off ratio of 103 at a drain voltage of -30 V. The inverter with a depletion p-type load showed a voltage inversion but the inversion occurred at the wrong voltage. The antifuse was successfully programmed with a voltage pulse and also a current pulse. The resistance decreased from 10 GΩ to 2 kΩ after the programming.

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