Biosensors [Biosensors (Basel)] 2023 May 14; Vol. 13 (5). Date of Electronic Publication: 2023 May 14.
Humans, Porosity, Electrodes, and Graphite
Flexible pressure sensors are widely applied in tactile perception, fingerprint recognition, medical monitoring, human-machine interfaces, and the Internet of Things. Among them, flexible capacitive pressure sensors have the advantages of low energy consumption, slight signal drift, and high response repeatability. However, current research on flexible capacitive pressure sensors focuses on optimizing the dielectric layer for improved sensitivity and pressure response range. Moreover, complicated and time-consuming fabrication methods are commonly applied to generate microstructure dielectric layers. Here, we propose a rapid and straightforward fabrication approach to prototyping flexible capacitive pressure sensors based on porous electrodes. Laser-induced graphene (LIG) is produced on both sides of the polyimide paper, resulting in paired compressible electrodes with 3D porous structures. When the elastic LIG electrodes are compressed, the effective electrode area, the relative distance between electrodes, and the dielectric property vary accordingly, thereby generating a sensitive pressure sensor in a relatively large working range (0-9.6 kPa). The sensitivity of the sensor is up to 7.71%/kPa -1 , and it can detect pressure as small as 10 Pa. The simple and robust structure allows the sensor to produce quick and repeatable responses. Our pressure sensor exhibits broad potential in practical applications in health monitoring, given its outstanding comprehensive performance combined with its simple and quick fabrication method.
Patterson ZJ, Patel DK, Bergbreiter S, Yao L, and Majidi C
Soft robotics [Soft Robot] 2023 Apr; Vol. 10 (2), pp. 292-300. Date of Electronic Publication: 2022 Jul 14.
Because they are made of elastically deformable and compliant materials, soft robots can passively change shape and conform to their environment, providing potential advantages over traditional robotics approaches. However, existing manufacturing workflows are often labor intensive and limited in their ability to create highly integrated three-dimensional (3D) heterogeneous material systems. In this study, we address this with a streamlined workflow to produce field-deployable soft robots based on 3D printing with digital light processing (DLP) of silicone-like soft materials. DLP-based 3D printing is used to create soft actuators (2.2 g) capable of exerting up to 0.5 Newtons of force that are integrated into a bioinspired untethered soft robot. The robot walks underwater at speeds comparable with its biological analog, the brittle star. Using a model-free planning algorithm and feedback, the robot follows remote commands to move to desired positions. Moreover, we show that the robot is able to perform untethered locomotion outside of a laboratory and in a natural aquatic environment. Our results represent progress in soft robot manufacturing autonomy for a 3D printed untethered soft robot.
Polymers [Polymers (Basel)] 2023 Mar 21; Vol. 15 (6). Date of Electronic Publication: 2023 Mar 21.
As part of this work, polymer composites based on polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) were obtained and used in 3D printing technology, particularly Melted Extrusion Modeling (MEM) technology. The influence of selected fillers on the properties of the obtained composites was investigated. For this purpose, modified fillers such as silica modified with alumina, bentonite modified with a quaternary ammonium salt, and hybrid lignin/silicon dioxide filler were introduced into the PC/ABS matrix. In the first part of this work, polymer blends and their composites containing 1.5-3 wt. of the filler were used to obtain the filament using the proprietary technological line. Moldings for testing the performance properties were obtained using additive manufacturing techniques and injection molding. In the subsequent part of this work, rheological properties (mass flow rate (MFR) and viscosity curves) and mechanical properties (Rockwell hardness and static tensile strength with Young's modulus) were examined. The structures of the obtained composites were also determined by scanning electron microscopy (SEM/EDS). The obtained results confirmed the results obtained from a wide-angle X-ray scattering analysis (WAXS). In turn, the physicochemical properties were characterized on the basis of the results of tests using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Based on the obtained results, it was found that the introduced modified additives had a significant impact on the processing and functional properties of the tested composites.
Micromachines [Micromachines (Basel)] 2023 Mar 14; Vol. 14 (3). Date of Electronic Publication: 2023 Mar 14.
In this paper, we report a simple, rapid, low-cost, biocompatible, and detachable microfluidic chip fabrication method for customized designs based on Parafilm ® . Here, Parafilm ® works as both a bonding agent and a functional membrane. Its high ultimate tensile stress (3.94 MPa) allows the demonstration of high-performance actuators such as microvalves and micropumps. By laser ablation and the one-step bonding of multiple layers, 3D structured microfluidic chips were successfully fabricated within 2 h. The consumption time of this method (~2 h) was 12 times less than conventional photolithography (~24 h). Moreover, the shear stress of the PMMA-Parafilm ® -PMMA specimens (0.24 MPa) was 2.13 times higher than that of the PDMS-PDMS specimens (0.08 MPa), and 0.56 times higher than that of the PDMS-Glass specimens (0.16 MPa), showing better stability and reliability. In this method, multiple easily accessible materials such as polymethylmethacrylate (PMMA), PVC, and glass slides were demonstrated and well-incorporated as our substrates. Practical actuation devices that required high bonding strength including microvalves and micropumps were fabricated by this method with high performance. Moreover, the biocompatibility of the Parafilm ® -based microfluidic devices was validated through a seven-day E. coli cultivation. This reported fabrication scheme will provide a versatile platform for biochemical applications and point-of-care diagnostics.
Sensors (Basel, Switzerland) [Sensors (Basel)] 2023 Mar 08; Vol. 23 (6). Date of Electronic Publication: 2023 Mar 08.
Humans, Communication, Software, and Language
Amidst the domestic labor shortage and worldwide pandemic in recent years, there has been an urgent need for a digital means that allows construction site workers, particularly site managers, to obtain information more efficiently in support of their daily managerial tasks. For workers who move around the site, traditional software applications that rely on a form-based interface and require multiple finger movements such as key hits and clicks can be inconvenient and reduce their willingness to use such applications. Conversational AI, also known as a chatbot, can improve the ease of use and usability of a system by providing an intuitive interface for user input. This study presents a demonstrative Natural Language Understanding (NLU) model and prototypes an AI-based chatbot for site managers to inquire about building component dimensions during their daily routines. Building Information Modeling (BIM) techniques are also applied to implement the answering module of the chatbot. The preliminary testing results show that the chatbot can successfully predict the intents and entities behind the inquiries raised by site managers with satisfactory accuracy for both intent prediction and the answer. These results provide site managers with alternative means to retrieve the information they need.
Kim J, Menichella B, Lee H, Dayton PA, and Pinton GF
Sensors (Basel, Switzerland) [Sensors (Basel)] 2022 Dec 28; Vol. 23 (1). Date of Electronic Publication: 2022 Dec 28.
Equipment Design, Transducers, Printing, Three-Dimensional, Ultrasonography, Ultrasonics, and Ultrasonic Therapy
We present a rapid prototyping method for sub-megahertz single-element piezoelectric transducers by using 3D-printed components. In most of the early research phases of applying new sonication ideas, the prototyping quickness is prioritized over the final packaging quality, since the quickness of preliminary demonstration is crucial for promptly determining specific aims and feasible research approaches. We aim to develop a rapid prototyping method for functional ultrasonic transducers to overcome the current long lead time (>a few weeks). Here, we used 3D-printed external housing parts considering a single matching layer and either air backing or epoxy-composite backing (acoustic impedance > 5 MRayl). By molding a single matching layer on the top surface of a piezoceramic in a 3D-printed housing, an entire packaging time was significantly reduced (<26 h) compared to the conventional methods with grinding, stacking, and bonding. We demonstrated this prototyping method for 590-kHz single-element, rectangular-aperture transducers for moderate pressure amplitudes (mechanical index > 1) at focus with temporal pulse controllability (maximum amplitude by <5-cycle burst). We adopted an air-backing design (Type A) for efficient pressure outputs, and bandwidth improvement was tested by a tungsten-composite-backing (Type B) design. The acoustic characterization results showed that the type A prototype provided 3.3 kPa/Vpp far-field transmitting sensitivity with 25.3% fractional bandwidth whereas the type B transducer showed 2.1 kPa/Vpp transmitting sensitivity with 43.3% fractional bandwidth. As this method provided discernable quickness and cost efficiency, this detailed rapid prototyping guideline can be useful for early-phase sonication projects, such as multi-element therapeutic ultrasound array and micro/nanomedicine testing benchtop device prototyping.
Robertson EP, Walsh DP, Martin J, Work TM, Kellogg CA, Evans JS, Barker V, Hawthorn A, Aeby G, Paul VJ, Walker BK, Kiryu Y, Woodley CM, Meyer JL, Rosales SM, Studivan M, Moore JF, Brandt ME, and Bruckner A
Journal of environmental management [J Environ Manage] 2023 Jul 01; Vol. 337, pp. 117668. Date of Electronic Publication: 2023 Mar 22.
Hammood M, Lin S, Yun H, Luan E, Chrostowski L, and Jaeger NAF
Optics letters [Opt Lett] 2023 Feb 01; Vol. 48 (3), pp. 582-585.
We demonstrate a method to emulate the optical performance of silicon photonic devices fabricated using advanced deep-ultraviolet lithography (DUV) processes on a rapid-prototyping electron-beam lithography process. The method is enabled by a computational lithography predictive model generated by processing SEM image data of the DUV lithography process. We experimentally demonstrate the emulation method's accuracy on integrated silicon Bragg grating waveguides and grating-based, add-drop filter devices, two devices that are particularly susceptible to DUV lithography effects. The emulation method allows silicon photonic device and system designers to experimentally observe the effects of DUV lithography on device performance in a low-cost, rapid-prototyping, electron-beam lithography process to enable a first-time-right design flow.
Zhang X, Son R, Lin YJ, Gill A, Chen S, Qi T, Choi D, Wen J, Lu Y, Lin NYC, and Chiou PY
Lab on a chip [Lab Chip] 2022 Nov 08; Vol. 22 (22), pp. 4327-4334. Date of Electronic Publication: 2022 Nov 08.
Acoustics and Lasers
Acoustic patterning of micro-particles has many important biomedical applications. However, fabrication of such microdevices is costly and labor-intensive. Among conventional fabrication methods, photo-lithography provides high resolution but is expensive and time consuming, and not ideal for rapid prototyping and testing for academic applications. In this work, we demonstrate a highly efficient method for rapid prototyping of acoustic patterning devices using laser manufacturing. With this method we can fabricate a newly designed functional acoustic device in 4 hours. The acoustic devices fabricated using this method can achieve sub-wavelength, complex and non-periodic patterning of microparticles and biological objects with a spatial resolution of 60 μm across a large active manipulation area of 10 × 10 mm 2 .
In this paper we examine the task of key gesture spotting: accurate and timely online recognition of hand gestures. We specifically seek to address two key challenges faced by developers when integrating key gesture spotting functionality into their applications. These are: i) achieving high accuracy and zero or negative activation lag with single-time activation; and ii) avoiding the requirement for deep domain expertise in machine learning. We address the first challenge by proposing a key gesture spotting architecture consisting of a novel gesture classifier model and a novel single-time activation algorithm. This key gesture spotting architecture was evaluated on four separate hand skeleton gesture datasets, and achieved high recognition accuracy with early detection. We address the second challenge by encapsulating different data processing and augmentation strategies, as well as the proposed key gesture spotting architecture, into a graphical user interface and an application programming interface. Two user studies demonstrate that developers are able to efficiently construct custom recognizers using both the graphical user interface and the application programming interface.