magnetic force
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2022 ◽  
Vol 12 (1) ◽  
pp. 113
Author(s):  
Sung-Hoon Kim ◽  
Dong-Min Ji ◽  
Chan-Yong Kim ◽  
Sung-Bok Choi ◽  
Min-Cheol Joo ◽  
...  

We developed a magnetic-force-based three-dimensional (3D) rehabilitation device that can perform motor rehabilitation treatment for paralyzed fingers, regardless of upper extremity movement and position, and investigated the therapeutic effects of the device. An end-effector type rehabilitation device that can generate magnetic fields in three directions was developed using electromagnets and permanent magnetics. A double-blinded randomized controlled pilot study was conducted with a total of 12 patients. The intervention group had rehabilitation treatment using the developed magnetic finger rehabilitation device for 30 min a day for four weeks. The control group underwent exercise rehabilitation treatment. The control group received conventional occupational therapy on the upper limbs, including hands, from an occupational therapist, for the same amount of time. Adverse effects were monitored, and the patient’s sensory or proprioceptive deficits were examined before the intervention. No participants reported safety concerns while the intervention was conducted. The Wolf Motor Function Test (WMFT) scores were significantly improved in the intervention group (from 13.4 ± 3.6 to 20.9 ± 4.0 points) compared to the control group (from 13.1 ± 4.0 to 15.2 ± 3.8 points) (p = 0.016). The patients in the intervention group (from 88 ± 12 to 67 ± 13 s) showed greater improvement of WMFT times compared to the control group (from 89 ± 10 to 73 ± 11 s) (p = 0.042). The Manual Function Test and the upper limb score of the Fugl-Meyer Assessment were significantly improved in the intervention group compared with the control group (p = 0.038 and p = 0.042). The patients in the intervention group also showed significantly greater enhancement of the Korean version of the modified Barthel Index than the control group (p = 0.042). Rehabilitation treatment using the 3D magnetic-force-driven finger rehabilitation device helped improve finger motor function and activities of daily living in subacute stroke patients.


Physics ◽  
2022 ◽  
Vol 4 (1) ◽  
pp. 21-36
Author(s):  
Brunello Tirozzi ◽  
Paolo Buratti

In this paper, a theory of force-free magnetic field useful for explaining the formation of convex closed sets, bounded by a magnetic separatrix in the plasma, is developed. This question is not new and has been addressed by many authors. Force-free magnetic fields appear in many laboratory and astrophysical plasmas. These fields are defined by the solution of the problem ∇×B=ΛB with some field conditions B∂Ω on the boundary ∂Ω of the plasma region. In many physical situations, it has been noticed that Λ is not constant but may vary in the domain Ω giving rise to many different interesting physical situations. We set Λ=Λ(ψ) with ψ being the poloidal magnetic flux function. Then, an analytic method, based on a first-order expansion of ψ with respect to a small parameter α, is developed. The Grad–Shafranov equation for ψ is solved by expanding the solution in the eigenfunctions of the zero-order operator. An analytic expression for the solution is obtained deriving results on the transition through resonances, the amplification with respect to the gun inflow. Thus, the formation of Spheromaks or Protosphera structure of the plasma is determined in the case of nonconstant Λ.


Author(s):  
Boo Young Hwang ◽  
Eunsoo Kim ◽  
Seung-ha Kim ◽  
Hyundoo Hwang

Carcinoembryonic antigen (CEA) is a biomarker indicated in different cancers, targeted for quantitative analysis via immunoassay. Here we introduce a new technique called magnetic force-assisted electrochemical sandwich immunoassay (MESIA) for determination of CEA level in a drop of human serum using a fully automated point-of-care testing (POCT) device. The analytical performances of the assay are assessed based on precision, accuracy, limit of blank (LoB), limit of detection (LoD) and limit of quantitation (LoQ), linearity, Hook effect, interference, cross-reactivity, and method comparison following the guidelines of the Clinical Laboratory Standards Institute (CLSI). The LoD is 0.50 ng/ml. A linear relationship is shown in the range of 0.5–200 ng/ml. A high dose effect is not seen up to approximately 500,000 ng/ml. The recovery range is from 94.7 to 108.9%. The %CV of run-to-run and within-lab variations are less than 2.04 and 4.41% across the CEA concentrations, respectively, whereas reproducibility is 4.45–6.24%. Method comparison shows that the assay correlates well with the reference device (R2 = 0.9884). The assay demonstrates acceptable precision, accuracy, LoB, LoD and LoQ, hook effect, linearity, interference, cross-reactivity, and high correlation with its reference device. Thus, the system is suitable for the quantification of CEA in clinical practices with a POCT manner.


IEEE Access ◽  
2022 ◽  
pp. 1-1
Author(s):  
Hasan N. Ali ◽  
Ahmad B. Hassanat ◽  
Ahmad S. Tarawneh ◽  
Malek Alrashidi ◽  
Mansoor Alghamdi ◽  
...  

2022 ◽  
Vol 14 (1) ◽  
pp. 168781402210743
Author(s):  
Sajid Rehman ◽  
Taza Gul ◽  
Waris Khan ◽  
Aamir Khan ◽  
Zeeshan

Investigations are performed for further observations of heat and mass transfer in magneto-hydrodynamic mixed-convectional nano-fluid flow with the assumption of variable viscosity and thermal-conductivity over an unsteady stretching sheet. Base fluid is Carboxy-methyl cellulose (CMC) water as a carrier fluid with different nano-particles such as [Formula: see text] (Titanium), Ag (Silver), [Formula: see text] (Aluminum), and Cu (Copper). Flow contains different physical parameters, such as heat source, chemical reaction effect, Schmidt number, and radiation absorptions effects are observed to be significant in the presences of magnetic field. Obtained equations are solved by numerically BVP4C-package (shooting method) and analytically by BVPh2.0-package (Homotopy Analysis Method “HAM”). Interested physical quantities are, viscosity-parameter ( A), Thermal-conductivity parameter ( N),Thermocapillary-number ( M), Hartmann-number (Ma), Prandtl-number (Pr), 4-nano-particles ([Formula: see text]), temperature Grashof number ([Formula: see text]), and mass Grashof number ([Formula: see text]) are the focus to the velocity, temperature, and solute concentration profiles. It is concluded that, Solute concentration of ([Formula: see text])-water has higher than the other 3-nano-fluids. Mass flux, heat flux, and Skin friction of fluids are direct functions of magnetic force, while inverse function of temperature. Magnetic force also decreased the speed of fluids and hence mass flux reduced which implies that, the temperature reduces. [Formula: see text] has also inverse relation with mass flux, heat flux, and skin friction, while direct relation with the speed of fluids. Similarly, [Formula: see text] has inverse relation with [Formula: see text], [Formula: see text], and [Formula: see text], but direct relation with [Formula: see text]. Different results are shown in graphical and tabular form.


2022 ◽  
Vol 2148 (1) ◽  
pp. 012004
Author(s):  
Zhong Guan

Abstract There discovered the maximum possible magnetic induction in nature, equal to the magnetic induction at the poles of an electron’s spin, When the spin magnetic moments of two electrons are close to each other, they act on each other with the maximum possible magnetic induction, and finally entered the maximally entangled state after the energy drops. By this time, the spin magnetic moments on both sides situated in anti-parallel, between them there existed four invisible magnetic circuit, and each magnetic circuit just contain a fluxon. No matter how far the distance between the spins, owing to the inalienability of fluxon, no magnetic flux leakage (coupling degree 100%), so these four magnetic circuit will always existed, maintaining the maximally entangled state system immutably. This is the material basis for the entangled state to be existed, nothing to do with “spooky action at a distance”. In this paper, a visual schematic diagram has drawn to describe these, and the magnetic force state, force relationship and “light barrier” problem are analyzed.


Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 115
Author(s):  
Jiaqi Wang ◽  
Zhenzhong Fan ◽  
Qingwang Liu ◽  
Qilei Tong ◽  
Biao Wang

The discharge of oily wastewater and oil spills at sea are the current difficulties in water pollution control. This problem often leads to terrible disasters. Therefore, the effective realization of oil-water separation is a very challenging problem. Superhydrophobic sponge is a promising oil-absorbing material. In this article, we reported a superhydrophobic sponge with nano-Fe3O4 for oil-water separation. The addition of nano-Fe3O4 allows the sponge to be recycled under the action of magnetic force. The sponge has the advantages of low cost, simple preparation and efficient oil-water separation. This kind of sponge is very worthy of promotion for the treatment of oily wastewater and marine oil spill accidents.


Author(s):  
Haoze Wang ◽  
Zhigang Wu ◽  
Kun Liu ◽  
Jingbo Wei ◽  
Hongjing Hu

This paper presents a novel permanent magnet (PM) bias hybrid thrust magnetic bearing (HTMB), which can be used to replace the traditional thrust magnetic bearings (TMBs) for high-speed rotating machinery. By adding two PM rings and by reducing the number of the control coils by half, this HTMB eliminates the bias current, reduces the number of amplifiers, and minimizes the magnetic bearing’s structure complexity and power consumption. The analytical modelling method of the HTMB is presented in this paper. Mathematical models for calculating the magnetic force capacity and the stiffnesses of this bearing are derived as simplified formulae, which can be used for the design, analysis, and control of this bearing. Electromechanical characteristics of the HTMB are analyzed, which is compared to the traditional TMB to demonstrate the advantages of the HTMB. The prototype of the HTMB is designed, analyzed, and fabricated, whereas, the 2-D FEM is used to verify the design and the analytical model. Finally, an experimental setup is constructed and tested. The analytical and experimental results indicate that the proposed novel topology of this HTMB is feasible and the presented analytical model is accurate.


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