2,238 research outputs found
An efficient marching-on-in-degree solution of transient multiscale EM scattering problems
A marching-on-in-degree (MOD)-based time-domain domain decomposition method is proposed to efficiently analyze the transient electromagnetic scattering from electrically large multiscale targets. The algorithm starts with an octree that divides the whole scattering target into several subdomains. Then using the equivalence principle algorithm, each subdomain is enclosed by an equivalence sphere (ES), where both the RWG and BoR spatial basis functions are employed to expand the unknown currents. The interactions of the near-field subdomains are directly calculated by the method of moments, while the far-field interactions can be converted into the interactions of corresponding ESs. This scheme implicitly satisfies the current continuity condition, and the convergence can be accelerated as well. By harnessing the rotational symmetry of the ESs, the computational resources are reduced significantly compared with the traditional MOD method. Several numerical examples are presented to demonstrate the accuracy and efficiency of the proposed algorithm. © 2016 IEEE.postprin
Adsorption of methylene blue dye from the aqueous solution via bio-adsorption in the inverse fluidized-bed adsorption column using the torrefied rice husk
In this work, the inverse fluidized-bed bio-adsorption column is applied for the first time and is demonstrated using the torrefied rice husk (TRH) for the removal of methylene blue from the solution. The bio-adsorbents were characterized by BET, FI-IR, and SEM. The inverse fluidized-bed adsorption column using TRH becomes saturated in the 95-min continuous adsorption, during which the breakthrough time is 22 min, the overall MB removal (R) is 84%, and the adsorption capacity (Qexp) on the TRH is 6.82 mg g−1. These adsorption characteristics are superior to those in the fixed-bed adsorption column (R of 52% and Qexp of 2.76 mg g−1) at a lower flow rate (100 vs. 283 cm3 min−1). Torrefaction of RH significantly increases the surface area (28 vs. 9 m2 g−1) and enhances the surface functional groups, leading to an improved maximum equilibrium adsorption amount from 21.5 to 38.0 mg g−1 according to Langmuir model in the batch adsorption system. Besides, the increased Qexp on the TRH is also obtained in the inverse fluidized-bed (5.25 vs. 2.77 mg g−1, 89% higher) and the fixed-bed (2.76 vs. 1.53 mg g−1, 80% higher) adsorption columns compared to that on the RH
Efficient Volumetric Method of Moments for Modeling Plasmonic Thin-Film Solar Cells with Periodic Structures
Metallic nanoparticles (NPs) support localized surface plasmon resonances
(LSPRs), which enable to concentrate sunlight at the active layer of solar
cells. However, full-wave modeling of the plasmonic solar cells faces great
challenges in terms of huge computational workload and bad matrix condition. It
is tremendously difficult to accurately and efficiently simulate near-field
multiple scattering effects from plasmonic NPs embedded into solar cells. In
this work, a preconditioned volume integral equation (VIE) is proposed to model
plasmonic organic solar cells (OSCs). The diagonal block preconditioner is
applied to different material domains of the device structure. As a result,
better convergence and higher computing efficiency are achieved. Moreover, the
calculation is further accelerated by two-dimensional periodic Green's
functions. Using the proposed method, the dependences of optical absorption on
the wavelengths and incident angles are investigated. Angular responses of the
plasmonic OSCs show the super-Lambertian absorption on the plasmon resonance
but near-Lambertian absorption off the plasmon resonance. The volumetric method
of moments and explored physical understanding are of great help to investigate
the optical responses of OSCs.Comment: 11 pages, 6 figure
Clinical significance of bladder training in preoperative localization of high-intensity focused ultrasound ablation of uterine fibroids
Objectives: High-intensity focused ultrasound (HIFU) is widely used to treat uterine fibroids. HIFU preoperative localization of uterine fibroids can be used to determine whether the patient is a suitable candidate for HIFU treatment. This study investigated the clinical significance of bladder training in improving the success rate of HIFU preoperative localization uterine fibroids.
Material and methods: Our sample consists of patients who planned to undergo HIFU treatment in our hospital but who were failed in previous HIFU preoperative localization. They were recruited between July 2021 and April 2022, and randomly divided into experimental and control groups. A total of 150 patients were enrolled. Each group consisted of 75 patients. The patients in the experimental group adopted the procedure of drinking water multiple times and retaining urine. The training program lasted three days. The patients in the control group were required to keep regular drinking and urination habits without any special instructions or requirements.
Results: There were no statistically significant differences between the two groups in maximum bladder capacity, residual urine volume of bladder, bladder filling levels, and bladder shape change. After bladder training, the maximum bladder capacity and the degree bladder shape change of the patients in the experimental group were improved significantly. The success rate of HIFU preoperative localization in the patients in the experimental group was significantly higher than that of the control group.
Conclusions: Bladder training can effectively improve the success rate of HIFU preoperative localization of uterine fibroids
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