Vortex trap manipulation of microscopic objects in three-dimensions by helical microswimmers has a great potential towards non-contact biological cell manipulation or microassembly. However, in the ...current state-of-the-art, it has been limited in 2D manipulation due to the conflicting characteristics of optimizing the trapping force and propulsion force. In this paper, we propose a new design of the helical microswimmers enabling purely non-contact, selective and 3D vortex trap micromanipulation. The proposed helical microswimmers are fabricated by 3D nanoprinting technology based on two-photon laser absorption. The vertically standing helical mirostructures on top of the supporting micropillars allows uniform coating of ferromagnetic metal layer with minimum shadow area during metallization by sputtering. Furthermore this reduces the risk of damaging or losing materials during micromanipulation process for releasing them after fabrication which allows propulsion force characterizations and optimization. We characterized to reveal their propulsion force and this proved the propulsion force was recovered back to even higher than the single helical microswimmers. We consider that the proposed helical microswimmers with 3D manipulation could have a great impact to non-contact biological cell manipulation.
•A new design of non-contact mobile micro-manipulator for 3D manipulation of cell-size particles is proposed•Design and fabrication process for increasing propulsion force and stability of bio-inspired helical micro-swimmer•D non-contact micro-manipulation is described and demonstrated. Display omitted
Bio-particles are usually considered as an elastic material, while it has been proven that these particles such as viruses and cells behave more like viscoelastic materials because of the liquid ...cytoplasm in cells and also the protein capsid around viruses; thus, this property is not ignorable because it leads to a non-precise prediction in simulations. On the other hand, the surface of these particles is usually considered smooth, while the topography shows asperities on them. In this paper, the viscoelastic contact model along with the asperities’ distribution of the bio-particles is considered near reality. Simulation results reveal that the prediction of the viscoelastic contact models is more precise and closer to the experimental data than the elastic state. Using experimental results and applying their effect, asperities’ radii are obtained and comparison shows that the rough viscoelastic theory is more accurate and closer to the experimental data in comparison with viscoelastic models without asperity. The simulation of the first phase of the manipulation, applying three states of the elastic, the viscoelastic, and the rough viscoelastic in addition to a comparison with similar modes, shows that in the particle’s sliding on the substrate, tip sliding on the particle, and the particle rolling modes, the critical force has the highest magnitudes in the rough viscoelastic, the elastic, and the viscoelastic, respectively. However, results for the critical time are different, i.e., the highest critical times are related to the elastic, the viscoelastic, and the rough viscoelastic states, respectively.
Virtual reality technologies (VR) have advanced rapidly in the last few years. Prime examples include the Oculus RIFT and HTC Vive that are both head-worn/mounted displays (HMDs). VR HMDs enable a ...sense of immersion and allow enhanced natural interaction experiences with 3D objects. In this research we explore suitable interactions for manipulating 3D objects when users are wearing a VR HMD. In particular, this research focuses on a user-elicitation study to identify natural interactions for 3D manipulation using dual-hand controllers, which have become the standard input devices for VR HMDs. A user elicitation study requires potential users to provide interactions that are natural and intuitive based on given scenarios. The results of our study suggest that users prefer interactions that are based on shoulder motions (e.g., shoulder abduction and shoulder horizontal abduction) and elbow flexion movements. In addition, users seem to prefer one-hand interaction, and when two hands are required they prefer interactions that do not require simultaneous hand movements, but instead interactions that allow them to alternate between their hands. Results of our study are applicable to the design of dual-hand interactions with 3D objects in a variety of virtual reality environments.
Since in the approximation made by the modeling and simulation of the manipulation, the accuracy plays an important role so it makes researchers to eliminate simplifications and limitations. Damping ...properties of the biological particles and consequently loading history of them is one of those simplifications considered until now. The other simplifying assumption is the ignorance of the oscillatory drag during modeling of the manipulation in a liquid environment elimination of which results in more precise modeling. To achieve this goal and increase the accuracy of the modeling in this paper, particles are considered viscoelastic and the oscillatory drag is added to the Stokes drag. To do so, several viscoelastic contact models are developed to choose the better suited model for biological particles. On the other hand, to modify the prediction of the particle and tool's behavior, ignored rotation about z axis is also considered. Obtained results show that considering particles viscoelastic leads to the decrease of the critical force in comparison with the elastic state. This is due to the decreasing of the deformation acceleration based on the particle's damping. These differences are about 29% for sliding of the tip on the particle, 8% for sliding of the particle on the substrate and 22% for rolling. Besides, application of the oscillatory drag force about 1.7nN leads to increasing of the drag which can be ignored in the modeling but in the case of high precision modeling this drag can be take into consideration. Therefore, it can be said that considering viscoelastic properties of the particle increases the accuracy of the modeling and simulation and as a result behavior prediction of the particles under manipulation.
For doctors and other medical professionals, the human body is the focus of their daily practice. A solid understanding of how it is built up, that is, the anatomy of the human body, is essential to ...ensure safe medical practice. Current anatomy education takes place either using text books or via dissecting human cadavers, with text books being the most traditional way to learn anatomy due to the cost of the alternatives. However, printed media offer only a 2D perception of a part of the human body. Although dissection of human cadavers can give a more direct observation and interaction with human bodies, it is extremely costly because of the need of preserving human bodies and maintaining dissection rooms. To solve this issue, we developed VeLight, a system with which students can learn anatomy based on CT datasets using a 3D Virtual Reality display (zSpace). VeLight offers simple and intuitive interactions, and allows teachers to design their own courses using their own material. The system offers an interactive, depth-perceptive learning experience and improves the learning process. We conducted an informal user study to validate the effectiveness of VeLight. The results show that participants were able to learn and remember how to work with VeLight very quickly. All participants reported enthusiasm for the potential of VeLight in the domain of medical education.
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In this study, we conducted an experiment using a mobile augmented reality (AR) system that allows direct manipulation of a virtual object with the user's hand and that presents material appearance ...of the object. The system presents user-perspective images on the mobile display, which enables natural interaction with virtual objects. We compared the methods with user-perspective and camera-perspective presentation using an object manipulation task for material perception. The result showed that the answer time in the task became significantly shorter with user-perspective presentation, which indicates that user-perspective presentation makes manipulation of virtual objects in mobile AR easier.
Due to the softness and vulnerability of biological cells, in manipulation operations, it is not possible to insert excessive force to move these cells. Also, cells in their living environment face ...with many dynamic factors; therefore, in order to prevent their destruction and death, consideration the environmental conditions, the theoretical studies that underlie the laboratory research should be closer to the actual results. So, in this article by simultaneous consideration of cell's viscoelasticity and asperities on its surface, as well as the correction of the viscoelastic constant in the liquid medium, the effects of the number of asperities on the contact area between cell and substrate on the manipulation process are investigated and by considering different mediums effects, cell's roughness and developed Hamaker for viscoelastic state, more accurate results of simulations are obtained. On the other hand, atomic force microscopy is also a powerful and multifunctional imaging device that provides observation and manipulation of biological samples, including single-cells, in a liquid medium. Consequently, in this study, using this device, the topography of the benign breast cancer cell is carried out in a liquid medium in contact mode. To correct the viscoelastic Hamaker constant, results are obtained using the Gwyddion software for extracting the roughness radius and the particle's height distribution function. In addition, simulation of the 3D manipulation for elastic and viscoelastic spherical bioactive particles in both air and liquid mediums is done applying particle's roughness with elastic and viscoelastic Hamaker constants. Results indicate that in the liquid medium due to changes in the adhesion force as well as the presence of drag force and surface tension, the critical force is reduced compared to air medium, and the effect of particle's roughness on the critical force and time is related to the number of asperities on the contact surface. Also, results are in good agreement with results of applying the particle's folding coefficient in the manipulation. In the second phase of the manipulation, the change trend in the manipulation force varies in different operating conditions.
3D Manipulation of Magnetic Liquid Metals Zhou, Wenqing; Liang, Qingxuan; Chen, Tianning
Advanced intelligent systems,
October 2020, 2020-10-00, 20201001, 2020-10-01, Volume:
2, Issue:
10
Journal Article
Peer reviewed
Open access
Herein, a new method for steering liquid metals (LMs) using only a magnetic field in open 3D space is proposed. The magnetic LM is composed of the alloy Galinstan and iron particles. The 3D ...horizontal and vertical manipulation of a magnetic LM can be realized via an external magnetic field. The magnetically actuated LM is not only manipulated on various complex pathways in the horizontal plane, but also vertically in 3D space without the use of electrolytes and electrodes. As a proof‐of‐principle, an intelligent delivery vehicle that can avoid obstacles and traps horizontally and overcome gravity vertically to offload a cargo is designed and implemented successfully. Furthermore, a biomimetic soft robotics that can realize both in‐plane and out‐of‐plane locomotion is demonstrated using only magnetic field. The novel 3D motion of the demonstrated system facilitates the development of practical LM‐based smart structures and devices.
A novel manipulating method for liquid metal (LM) in open 3D space using only a magnetic field, for the first time, is proposed experimentally. As a proof‐of‐concept, an intelligent delivery vehicle and a biomimetic soft robotics are demonstrated to validate the extraordinary steering performance that can facilitate the development of practical LM‐based smart structures and devices.
Multitouch displays represent a promising technology for the display and manipulation of data. While the manipulation of 2D data has been widely explored, 3D manipulation with multitouch displays ...remains largely unexplored. Based on an analysis of the integration and separation of degrees of freedom, we propose a taxonomy for 3D manipulation techniques with multitouch displays. Using that taxonomy, we introduce Depth-Separated Screen-Space (DS3), a new 3D manipulation technique based on the separation of translation and rotation. In a controlled experiment, we compared DS3 with Sticky Tools and Screen-Space. Results show that separating the control of translation and rotation significantly affects performance for 3D manipulation, with DS3 performing faster than the two other techniques.
The previous three degrees of freedom (DOF) 3D touch translations require more than one finger (usually two hands) to be performed, which limits their usability on mobile devices that need one hand ...to be held in most occasions. Given that the pressure-sensitive touch screen will become ubiquitous in the near future, we presented a pressure-based 3DOF 3D positioning technique that only uses one finger in operating. Our technique collects the normal force of the touch pressure and uses it to represent the depth value in 3D translating. Then we conducted several groups of tightly controlled user studies to conclude (1) how different strategies of pressure recognition will affect 3D translating and (2) how is the performance of the pressure-based manipulation compared to the previous two-fingered technique. Finally, we discussed some guidelines to help developers in the design of the pressure-sensing technique in 3D manipulations.
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