scholarly journals 3D Printed Ultrastretchable, Hyper-Antifreezing Conductive Hydrogel for Sensitive Motion and Electrophysiological Signal Monitoring

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Zhaolong Wang ◽  
Lei Chen ◽  
Yiqin Chen ◽  
Peng Liu ◽  
Huigao Duan ◽  
...  

Conductive hydrogels with high stretchability can extend their applications as a flexible electrode in electronics, biomedicine, human-machine interfaces, and sensors. However, their time-consuming fabrication and narrow ranges of working temperature and working voltage severely limit their further potential applications. Herein, a conductive nanocomposite network hydrogel fabricated by projection microstereolithography (PμSL) based 3D printing is proposed, enabling fast fabrication ability with high precision. The 3D printed hydrogels exhibit ultra-stretchability (2500%), hyper-antifreezing (-125°C), extremely low working voltage (<100 μV), and super cyclic tensile stability (1 million cycles). The hydrogel-based strain sensor can probe both large-scale and tiny human motions, even with ultralow voltage of 100 μV at extremely low temperature around −115°C. It is demonstrated that the present hydrogels can be used as a flexible electrode for capturing human electrophysiological signals (EOG and EEG), where the alpha and beta waves from the brain can be recorded precisely. Therefore, the present hydrogels will pave the way for the development of next-generation intelligent electronics, especially for those working under extremely low-temperature environments.

2019 ◽  
Vol 14 (1) ◽  
pp. 25-44 ◽  
Author(s):  
Andrei Jipa ◽  
Mathias Bernhard ◽  
Nicolas Ruffray ◽  
Timothy Wangler ◽  
Robert Flatt ◽  
...  

The pursuit for complex geometries in contemporary architecture is driving innovation towards an unconstrained fabrication freedom for building components. Concrete is a building material with excellent structural and architectural qualities, which has the theoretical capacity of being cast into any shape. However, in practice, concrete is generally limited by the formwork manufacturing industry to simple, planar shapes. To overcome this fabrication limitation, this research investigates the use of large-scale 3D-printed plastic formworks for concrete components. This novel construction method takes advantage of the load-bearing capacity of concrete and relies on the fabrication-freedom inherited from the 3D printed formwork, thus making complex topologies and precise details possible for concrete structures. To demonstrate the potential applications of this method, skelETHon —a functional four-meter-long concrete canoe— was designed, built and raced in a regatta on the Rhine river. The research focused on the optimization of the 3D printing process for large-scale plastic formworks and on improving the stability of the thin formwork shells during casting.


2015 ◽  
Vol 18 (3) ◽  
pp. 47-54
Author(s):  
Thu Thi Hoang ◽  
Hoa Tran My Huynh ◽  
Trung Quang Tran

Graphene has been enjoyed significant recent attention due to its potential applications in electronic and optoelectronic devices. Graphene is usually prepared via Hummers' method or modified Hummers' methods. These methods are the most suitable for the large-scale production of single graphene at low cost. But their main drawbacks are the use of strong oxidizing agents which make graphene films separating into small sheets and this extremely decrease the electrical conductivity of graphene. Herein, we report an inexpensive, fast and facile method for preparation of a double layer structured transparent, flexible hybrid electrode from silver nanowires (Ag NWs) with chemically converted graphene (CCG) coating on arbitrary substrate. These films dramatically decreases the resistance of graphene films and exhibited high optical transmittance (82.4 %) and low sheet resistance (18 Ω/ sq), which is comparable to ITO transparent electrode. The ratio of direct conductivity to optical conductivity DC/OP = 104 of this electrode is very close to that displayed by commercially available ITO. Especially, the whole fabrication process is carried out at low temperature. The graphene films are spin coated directly on the substrate without transferring therefore eliminating troubles that are brought from the transfer method.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1021
Author(s):  
Bernhard Dorweiler ◽  
Pia Elisabeth Baqué ◽  
Rayan Chaban ◽  
Ahmed Ghazy ◽  
Oroa Salem

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.


Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 682
Author(s):  
Bruno Henrique Silva Dias ◽  
Sung-Hee Jung ◽  
Juliana Velasco de Castro Oliveira ◽  
Choong-Min Ryu

Plant growth-promoting rhizobacteria (PGPR) associated with plant roots can trigger plant growth promotion and induced systemic resistance. Several bacterial determinants including cell-wall components and secreted compounds have been identified to date. Here, we review a group of low-molecular-weight volatile compounds released by PGPR, which improve plant health, mostly by protecting plants against pathogen attack under greenhouse and field conditions. We particularly focus on C4 bacterial volatile compounds (BVCs), such as 2,3-butanediol and acetoin, which have been shown to activate the plant immune response and to promote plant growth at the molecular level as well as in large-scale field applications. We also disc/ uss the potential applications, metabolic engineering, and large-scale fermentation of C4 BVCs. The C4 bacterial volatiles act as airborne signals and therefore represent a new type of biocontrol agent. Further advances in the encapsulation procedure, together with the development of standards and guidelines, will promote the application of C4 volatiles in the field.


2021 ◽  
Vol 45 (1) ◽  
pp. 208-216
Author(s):  
Zhonghua Zhao ◽  
Xiang Yuan ◽  
Yicheng Huang ◽  
Jikui Wang

Conductive hydrogels are promising flexible conductors for human motion monitoring.


2021 ◽  
Vol 7 (3) ◽  
pp. 58
Author(s):  
Carolina Font-Palma ◽  
David Cann ◽  
Chinonyelum Udemu

Our ever-increasing interest in economic growth is leading the way to the decline of natural resources, the detriment of air quality, and is fostering climate change. One potential solution to reduce carbon dioxide emissions from industrial emitters is the exploitation of carbon capture and storage (CCS). Among the various CO2 separation technologies, cryogenic carbon capture (CCC) could emerge by offering high CO2 recovery rates and purity levels. This review covers the different CCC methods that are being developed, their benefits, and the current challenges deterring their commercialisation. It also offers an appraisal for selected feasible small- and large-scale CCC applications, including blue hydrogen production and direct air capture. This work considers their technological readiness for CCC deployment and acknowledges competing technologies and ends by providing some insights into future directions related to the R&D for CCC systems.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Soren Wainio-Theberge ◽  
Annemarie Wolff ◽  
Georg Northoff

AbstractSpontaneous neural activity fluctuations have been shown to influence trial-by-trial variation in perceptual, cognitive, and behavioral outcomes. However, the complex electrophysiological mechanisms by which these fluctuations shape stimulus-evoked neural activity remain largely to be explored. Employing a large-scale magnetoencephalographic dataset and an electroencephalographic replication dataset, we investigate the relationship between spontaneous and evoked neural activity across a range of electrophysiological variables. We observe that for high-frequency activity, high pre-stimulus amplitudes lead to greater evoked desynchronization, while for low frequencies, high pre-stimulus amplitudes induce larger degrees of event-related synchronization. We further decompose electrophysiological power into oscillatory and scale-free components, demonstrating different patterns of spontaneous-evoked correlation for each component. Finally, we find correlations between spontaneous and evoked time-domain electrophysiological signals. Overall, we demonstrate that the dynamics of multiple electrophysiological variables exhibit distinct relationships between their spontaneous and evoked activity, a result which carries implications for experimental design and analysis in non-invasive electrophysiology.


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