scholarly journals 3D-Printed Miniature Robots with Piezoelectric Actuation for Locomotion and Steering Maneuverability Applications

Actuators ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 335
Author(s):  
Víctor Ruiz-Díez ◽  
José Luis García-Caraballo ◽  
Jorge Hernando-García ◽  
José Luis Sánchez-Rojas
Keyword(s):  
Large Scale ◽  
Driving Frequency ◽  
Piezoelectric Actuation ◽  
Miniature Robots ◽  
Differential Drive ◽  
3D Printed ◽  
Technological Impact ◽  
Hostile Environments ◽  
Complex Trajectories ◽  
Potential Use

The miniaturization of robots with locomotion abilities is a challenge of significant technological impact in many applications where large-scale robots have physical or cost restrictions. Access to hostile environments, improving microfabrication processes, or advanced instrumentation are examples of their potential use. Here, we propose a miniature 20 mm long sub-gram robot with piezoelectric actuation whose direction of motion can be controlled. A differential drive approach was implemented in an H-shaped 3D-printed motor platform featuring two plate resonators linked at their center, with built-in legs. The locomotion was driven by the generation of standing waves on each plate by means of piezoelectric patches excited with burst signals. The control of the motion trajectory of the robot, either translation or rotation, was attained by adjusting the parameters of the actuation signals such as the applied voltage, the number of applied cycles, or the driving frequency. The robot demonstrated locomotion in bidirectional straight paths as long as 65 mm at 2 mm/s speed with a voltage amplitude of only 10 V, and forward and backward precise steps as low as 1 µm. The spinning of the robot could be controlled with turns as low as 0.013 deg. and angular speeds as high as 3 deg./s under the same conditions. The proposed device was able to describe complex trajectories of more than 160 mm, while carrying 70 times its own weight.

scholarly journals Quality Control in 3D Printing: Accuracy Analysis of 3D-Printed Models of Patient-Specific Anatomy

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1021
Author(s):  
Bernhard Dorweiler ◽  
Pia Elisabeth Baqué ◽  
Rayan Chaban ◽  
Ahmed Ghazy ◽  
Oroa Salem
Keyword(s):  
Wall Thickness ◽  
Large Scale ◽  
Fused Deposition Modeling ◽  
Vascular Anatomy ◽  
3D Models ◽  
Patient Specific ◽  
Stl File ◽  
Fused Deposition ◽  
3D Printed ◽  
The Mean

As comparative data on the precision of 3D-printed anatomical models are sparse, the aim of this study was to evaluate the accuracy of 3D-printed models of vascular anatomy generated by two commonly used printing technologies. Thirty-five 3D models of large (aortic, wall thickness of 2 mm, n = 30) and small (coronary, wall thickness of 1.25 mm, n = 5) vessels printed with fused deposition modeling (FDM) (rigid, n = 20) and PolyJet (flexible, n = 15) technology were subjected to high-resolution CT scans. From the resulting DICOM (Digital Imaging and Communications in Medicine) dataset, an STL file was generated and wall thickness as well as surface congruency were compared with the original STL file using dedicated 3D engineering software. The mean wall thickness for the large-scale aortic models was 2.11 µm (+5%), and 1.26 µm (+0.8%) for the coronary models, resulting in an overall mean wall thickness of +5% for all 35 3D models when compared to the original STL file. The mean surface deviation was found to be +120 µm for all models, with +100 µm for the aortic and +180 µm for the coronary 3D models, respectively. Both printing technologies were found to conform with the currently set standards of accuracy (<1 mm), demonstrating that accurate 3D models of large and small vessel anatomy can be generated by both FDM and PolyJet printing technology using rigid and flexible polymers.

scholarly journals Evaluation of a Low-Cost Commercial Actigraph and Its Potential Use in Detecting Cultural Variations in Physical Activity and Sleep

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3774
Author(s):  
Pavlos Topalidis ◽  
Cristina Florea ◽  
Esther-Sevil Eigl ◽  
Anton Kurapov ◽  
Carlos Alberto Beltran Leon ◽  
...  
Keyword(s):  
Physical Activity ◽  
Low Income ◽  
Large Scale ◽  
Low Cost ◽  
Low Income Countries ◽  
Time Data ◽  
Cultural Variations ◽  
Step Counts ◽  
Scale Step ◽  
Potential Use

The purpose of the present study was to evaluate the performance of a low-cost commercial smartwatch, the Xiaomi Mi Band (MB), in extracting physical activity and sleep-related measures and show its potential use in addressing questions that require large-scale real-time data and/or intercultural data including low-income countries. We evaluated physical activity and sleep-related measures and discussed the potential application of such devices for large-scale step and sleep data acquisition. To that end, we conducted two separate studies. In Study 1, we evaluated the performance of MB by comparing it to the GT3X (ActiGraph, wGT3X-BT), a scientific actigraph used in research, as well as subjective sleep reports. In Study 2, we distributed the MB across four countries (Austria, Germany, Cuba, and Ukraine) and investigated physical activity and sleep among these countries. The results of Study 1 indicated that MB step counts correlated highly with the scientific GT3X device, but did display biases. In addition, the MB-derived wake-up and total-sleep-times showed high agreement with subjective reports, but partly deviated from GT3X predictions. Study 2 revealed similar MB step counts across countries, but significant later wake-up and bedtimes for Ukraine than the other countries. We hope that our studies will stimulate future large-scale sensor-based physical activity and sleep research studies, including various cultures.

A novel 3D-printed multi-driven system for large-scale neurophysiological recordings in multiple brain regions

2021 ◽  
pp. 109286
Author(s):  
Tao Sheng ◽  
Danqin Xing ◽  
Yi Wu ◽  
Qiao Wang ◽  
Xiangyao Li ◽  
...  
Keyword(s):  
Large Scale ◽  
Brain Regions ◽  
Driven System ◽  
3D Printed

scholarly journals A new pest management research facility Scions largescale precision track sprayer

2014 ◽  
Vol 67 ◽  
pp. 267-273
Author(s):  
S.F. Gous ◽  
T.M. Withers ◽  
A.J. Hewitt
Keyword(s):  
Large Scale ◽  
Spray Deposition ◽  
Management Research ◽  
Application Research ◽  
Pesticide Application ◽  
Research Facility ◽  
Liquid Pressure ◽  
Plant Canopies ◽  
Wide Range ◽  
Potential Use

A new large scale precision track sprayer has been developed and evaluated for spray deposition and pesticide application research under controlled conditions The spray room is fitted with a 4 m wide electrically driven boom suspended 4 m above ground running on a 12 m long Ibeam It is fitted with 9 independently controlled shut off valves and nozzles Sprays can be applied to live plant canopies up to 3 m tall within a 2 m times; 3 m sample area The number location and type of nozzle on the boom can be altered as can spray liquid pressure and boom speed in order to simulate a wide range of spray application scenarios Calibration of the largescale precision track sprayer has been undertaken for a range of droplet spectra from extremely coarse to very fine This paper documents the calibration results and discusses the potential use of this facility for pesticide application research

Use of polymer concrete for large-scale 3D printing

2021 ◽  
Vol 27 (3) ◽  
pp. 465-474
Author(s):  
Martin Krčma ◽  
David Škaroupka ◽  
Petr Vosynek ◽  
Tomáš Zikmund ◽  
Jozef Kaiser ◽  
...  
Keyword(s):  
3D Printing ◽  
Large Scale ◽  
Mechanical Performance ◽  
Construction Material ◽  
Polymer Concrete ◽  
Fused Deposition Modelling ◽  
Cast State ◽  
Content Type ◽  
Fused Deposition ◽  
3D Printed

Purpose This paper aims to focus on the evaluation of a polymer concrete as a three-dimensional (3D) printing material. An associated company has developed plastic concrete made from reused unrecyclable plastic waste. Its intended use is as a construction material. Design/methodology/approach The concrete mix, called PolyBet, composed of polypropylene and glass sand, is printed by the fused deposition modelling process. The process of material and parameter selection is described. The mechanical properties of the filled material were compared to its cast state. Samples were made from castings and two different orientations of 3D-printed parts. Three-point flex tests were carried out, and the area of the break was examined. Computed tomography of the samples was carried out. Findings The influence of the 3D printing process on the material was evaluated. The mechanical performance of the longitudinal samples was close to the cast state. There was a difference in the failure mode between the states, with cast parts exhibiting a tougher behaviour, with fractures propagating in a stair-like manner. The 3D-printed samples exhibited high degrees of porosity. Originality/value The results suggest that the novel material is a good fit for 3D printing, with little to no degradation caused by the process. Layer adhesion was shown to be excellent, with negligible effect on the finished part for the longitudinal orientation. That means, if large-scale testing of buildability is successful, the material is a good fit for additive manufacturing of building components and other large-scale structures.

History of Additive Manufacturing

2017 ◽  
pp. 1-24 ◽  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Large Scale ◽  
Selective Laser Sintering ◽  
3D Printer ◽  
3D Objects ◽  
History Of ◽  
Pros And Cons ◽  
3D Printed ◽  
The Common

History of additive manufacturing started in the 1980s in Japan. Stereolithography was invented first in 1983. After that tens of other techniques were invented under the common name 3D printing. When stereolithography was invented rapid prototyping did not exists. Tree years later new technique was invented: selective laser sintering (SLS). First commercial SLS was in 1990. At the end of 20t century, first bio-printer was developed. Using bio materials, first kidney was 3D printed. Ten years later, first 3D Printer in the kit was launched to the market. Today we have large scale printers that printed large 3D objects such are cars. 3D printing will be used for printing everything everywhere. List of pros and cons questions rising every day.

The Use of Microbial Coatings, Nutrients and Chemical Defense Systems in Oyster Restoration

2019 ◽  
Vol 53 (4) ◽  
pp. 39-54
Author(s):  
Thomas J. Manning ◽  
Weldon Lane ◽  
Richard Darren Williams ◽  
Matt Cowan ◽  
Marcus Diaz ◽  
...  
Keyword(s):  
Chemical Defense ◽  
Large Scale ◽  
Bulk Material ◽  
Keystone Species ◽  
Oyster Spat ◽  
Marine Life ◽  
Defense Systems ◽  
Improve Water Quality ◽  
Oyster Restoration ◽  
Potential Use

AbstractMany oyster species are keystone species that help mitigate shoreline erosion, provide habitats for juvenile fishes, and improve water quality. A number of human-driven factors have led to a decline in their populations worldwide. This article focuses on the chemistry of a novel substrate (nutrient-enriched concrete, or NEC) used to induce settlement and colonization of wild diploid oyster spat and is divided into four sections: (1) composition of the bulk material used for oyster restoration, (2) nutrients added to stimulate growth of bacterial and or algal biofilms, (3) nutrients included for the recently settled oyster spat, and (4) the potential use of natural chemical defense systems to control predators and competing marine life. The goal is to develop a material that can be manufactured and used on a large scale.

scholarly journals Antimicrobial activity of Moringa oleifera: A short review

2020 ◽  
Vol 12 (1) ◽  
pp. 128-132
Author(s):  
I.A. Raubilu ◽  
U. Isah ◽  
M.A. Ahmad
Keyword(s):  
Antimicrobial Activity ◽  
Middle East ◽  
Key Words ◽  
Large Scale ◽  
Moringa Oleifera ◽  
Short Review ◽  
Medicinal Properties ◽  
Pathogenic Microbes ◽  
Potential Use ◽  
Moringa Oleifera Lam

Moringa oleifera Lam. (Family Moringaceae) is well – known for its various medicinal properties. It grows wild in the tropical and subtropical areas of Asia, Africa and the Middle East. In Nigeria, Moringa oleifera trees are planted at a large scale especially in the northern part of the country. It has been widely used in the treatment of certain diseases as a traditional medicinal herb. Antimicrobial activity is the most studied property of Moringa oleifera. Many studies have shown that nearly all types of Moringa oleifera tissues exhibit antimicrobial activity including antibacterial, antifungal, antiviral and anti parasitic property. This review describes progress on research conducted to understand the antimicrobial activity of Moringa oleifera and discusses the potential use of Moringa oleifera in the control of pathogenic microbes. Key words: Antimicrobial activity; Moringa oleifera; pathogenic microbes, control.  

scholarly journals A Class-E Amplifier for a Loosely Coupled Inductive Power Transfer System with Multiple Receivers

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1165 ◽  
Author(s):  
Alexander Sutor ◽  
Martin Heining ◽  
Rainer Buchholz
Keyword(s):  
Penetration Depth ◽  
Large Scale ◽  
Near Field ◽  
Intermediate Frequency ◽  
Power Input ◽  
Magnetic Flux Density ◽  
Driving Frequency ◽  
Light Emitters ◽  
Custom Made ◽  
Class E

We present a method for optimizing the electronic power system for a new type of photobioreactor or photoreactor in general. In the case of photobioreactors, photosynthetic active microorganisms or cells are grown. A novel concept for the illumination of photobioreactors was necessary, as the external illumination of those reactors leads to a limited penetration depth of light. Due to the limited penetration depth, no standard reactors can be use for cultivation, but custom made reactors with very small volume to surface ratio have to be used. This still prevents the technology from a large scale industrial impact. The solution we propose in this paper is an internal illumination via Wireless Light Emitters. This increases the manageable culture volume of photosynthetic active microorganisms or cells. The illumination system is based on floating light emitters, which are powered wirelessly by near field resonant inductive coupling. The floating light emitters are able to illuminate a photobioreactor more homogeneously than external illumination systems do. We designed a class-E amplifier and field coils to produce an intermediate frequency electromagnetic field inside the reactor. An appropriate magnetic flux density was found to be approx. B = 1 mT and the driving frequency is f = 176 kHz. We conducted experiments with a laboratory size photoreactor. The cultivation volume was 30 L containing up to 3000 WLEs. The maximum electric power input was more than 300 W and we calculated an efficiency of up to 76%.

scholarly journals Surface Preparation and Treatment for Large-Scale 3D-Printed Composite Tooling Coating Adhesion

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 457 ◽  
Author(s):  
Philipp Sauerbier ◽  
James Anderson ◽  
Douglas Gardner
Keyword(s):  
Additive Manufacturing ◽  
Large Scale ◽  
Lower Cost ◽  
Numerical Control ◽  
Fused Deposition Modelling ◽  
Filler Materials ◽  
Coating Adhesion ◽  
Fused Deposition ◽  
Composite Tooling ◽  
3D Printed

Recent advances in large-scale thermoplastic additive manufacturing (AM), using fused deposition modelling (FDM), have shown that the technology can effectively produce large aerospace tools with common feed stocks, costing 2.3 $/kg, such as a 20% carbon-filled acrylonitrile butadiene styrene (ABS). Large-scale additive manufacturing machines have build-volumes in the range of cubic meters and use commercially available pellet feedstock thermoplastics, which are significantly cheaper (5–10 $/kg) than the filament feedstocks for desktop 3D printers (20–50 $/kg). Additionally, large-scale AM machines have a higher material throughput on the order of 50 kg/h. This enables the cost-efficient tool production for several industries. Large-scale 3D-printed tooling will be computerized numerical control (CNC)-machined and -coated, to provide a surface suitable for demolding the composite parts. This paper outlines research undertaken to review and improve the adhesion of the coating systems to large, low-cost AM composite tooling, for marine or infrastructure composite applications. Lower cost tooling systems typically have a lower dimensional accuracy and thermal operating requirements than might be required for aerospace tooling. As such, they can use lower cost commodity grade thermoplastics. The polymer systems explored in the study included polypropylene (PP), styrene-maleic anhydride (SMA), and polylactic acid (PLA). Bio-based filler materials were used to reduce cost and increase the strength and stiffness of the material. Fillers used in the study included wood flour, at 30% by weight and spray-dried cellulose nano-fibrils, at 20% by weight. Applicable adhesion of the coating was achieved with PP, after surface treatment, and untreated SMA and PLA showed desirable coating adhesion results. PLA wood-filled composites offered the best properties for the desired application and, furthermore, they have environment-friendly advantages.

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