Electrostatic tweezer for droplet manipulation

Various physical tweezers for manipulating liquid droplets based on optical, electrical, magnetic, acoustic, or other external fields have emerged and revolutionized research and application in medical, biological, and environmental fields. Despite notable progress, the existing modalities for droplet control and manipulation are still limited by the extra responsive additives and relatively poor controllability in terms of droplet motion behaviors, such as distance, velocity, and direction. Herein, we report a versatile droplet electrostatic tweezer (DEST) for remotely and programmatically trapping or guiding the liquid droplets under diverse conditions, such as in open and closed spaces and on flat and tilted surfaces as well as in oil medium. DEST, leveraging on the coulomb attraction force resulting from its electrostatic induction to a droplet, could manipulate droplets of various compositions, volumes, and arrays on various substrates, offering a potential platform for a series of applications, such as high-throughput surface-enhanced Raman spectroscopy detection with single measuring time less than 20 s.

Enhancing Robots Navigation in Internet of Things Indoor Systems

In this study, an effective local minima detection and definition algorithm is introduced for a mobile robot navigating through unknown static environments. Furthermore, five approaches are presented and compared with the popular approach wall-following to pull the robot out of the local minima enclosure namely; Random Virtual Target, Reflected Virtual Target, Global Path Backtracking, Half Path Backtracking, and Local Path Backtracking. The proposed approaches mainly depend on changing the target location temporarily to avoid the original target’s attraction force effect on the robot. Moreover, to avoid getting trapped in the same location, a virtual obstacle is placed to cover the local minima enclosure. To include the most common shapes of deadlock situations, the proposed approaches were evaluated in four different environments; V-shaped, double U-shaped, C-shaped, and cluttered environments. The results reveal that the robot, using any of the proposed approaches, requires fewer steps to reach the destination, ranging from 59 to 73 m on average, as opposed to the wall-following strategy, which requires an average of 732 m. On average, the robot with a constant speed and reflected virtual target approach takes 103 s, whereas the identical robot with a wall-following approach takes 907 s to complete the tasks. Using a fuzzy-speed robot, the duration for the wall-following approach is greatly reduced to 507 s, while the reflected virtual target may only need up to 20% of that time. More results and detailed comparisons are embedded in the subsequent sections.

Study for a Wall-Climbing Robot Magnetic Attraction Force of An Electronically Controlled Permanent Magnet

With the advancement in science and technology, a wall-climbing robot attached to the ship's outer surface is increasingly replacing humans in the rust removal. The magnetic force is not just the adsorption force but also the moving resistance force, which is currently the technological bottleneck in wall-climbing robotics based on magnetic adsorption. This paper proposes a novel wall-climbing robot based on electrically controlled permanent magnet technology to solve this problem. An electrically controlled permanent magnetic wall-climbing robot is proposed to realize the function of magnetization and demagnetization by changing the pulse current. The results of the experiments reveal that the magnetizing force is adequately adsorbed on the ship's outer surface. The magnetic attraction force is close to 0 N during demagnetization, meaning that the system is fully unloaded, as predicted by the theoretical analysis.

USE OF THE MAGNETORESISTIVE MAGNETIC FIELD SENSORS FOR THE TESTING OF THE LINEAR INDUCTION MOTORS

The magnetic field of an LIM is more complex than that of a rotating induction motor. At analysis of LIM the limited dimensions of the inductor should be considered. Therefore, it is necessary to investigate the magnetic fields beyond the inductor boundaries (edge effect and end effect), and interdependencies of these fields. Because of the phenomenon of end effect, additional factors must be considered: there is a reduction of attraction force, and despite a balanced supply voltage, increased phase impedance and phase differences of leading currents. The first task is to measure the magnetic field parameter of LIM by using a hall sensor and CMR.

Relativity Tied to Repulsion Gravity

This article refutes the Time Dilation Equation and Length Contraction that are derived in the Special Theory of Relativity. The conclusion reached in this article is that Time Dilation and Length Contraction cannot be characterized by simple equations due to repulsion gravity. The conclusion follows from gravity being a natural force of repulsion rather than the assumption that gravity is an attraction force. That gravity is a repulsion force follows from the Sir Arthur Eddington experiment designed to prove that gravity affects light. Few looked at that experiment as anything other than proving Einstein’s General Theory of Relativity that suggested gravity would affect light. The experiment went beyond what most imagined it accomplished. It surely verified that gravity affects light. But it did more than that. The experiment showed that gravity is a force of repulsion and not attraction as most believed. That gravity is repulsion and not an attraction force indicates that the relativity time dilation equation derived in the Special Theory of Relativity is intractably undecidable likely subject to Godels Incompleteness theorems

Analysis of Potential of Raising Forces Acting on Electroadhesive Pads Depending on Polarization and Supply Parameters

This paper reports the results of a study concerned with use of electroadhesion for investigation of the attraction force of paper (weight of 50 g/m2). For this purpose, a measuring system was developed and built. Next, a dedicated electroadhesive pad coated with copper and copper mesh on the other side was designed. A new supply control algorithm was also developed and a dedicated charger was built for the purpose of this study. The measurements were carried out with a tensiometer to measure the force with which the electroadhesive pad attracted paper. The research was carried out in a series of several experiments and involved shifting the polarity of the pad and depolarizing the entire system.

Design Optimization of Permanent Magnet Clutch with Ārtap Framework

So far, Permanent Magnet (PM) clutches have been broadly used as torque transmission devices. With the aim of effective utilization of materials and energy in the manufacturing of PM clutches, design optimization has been widely applied. Generally, PM clutches are optimized applying linear dimensions as optimization parameters. On the contrary, optimization of PM clutch shapes has not been done extensively. Therefore, this paper performs optimization of PM clutch shapes with the following objectives: maximum tangential attraction force and minimum volume of utilized materials. To form optimal shapes, the points on the clutch surface are chosen as optimization parameters. The optimization is carried out using Ārtap framework in connection with COMSOL software, where the 3D model of the clutch has been created. After the optimization, the tangential attraction force has increased by 13 % and the volume of the clutch has been reduced by 24 %. Although the obtained shapes appear to be highly intricate, it does not pose an obstacle for modern manufacturing techniques.

Design Optimization of a Permanent Magnet Clutch with Ārtap Framework

This paper performs optimization of permanent magnet clutch shapes with the following objectives: maximum tangential attraction force and minimum volume of utilized materials. To form optimal shapes, the points on the clutch surface are chosen as optimization parameters. The optimization is carried out using Ārtap framework in connection with COMSOL software, where the 3D model of the clutch has been created. After the optimization, the tangential attraction force has increased by 13% and the volume of the clutch has been reduced by 24%.