The Hybrid FEM-DBCI for the Solution of Open-Boundary Low-Frequency Problems

This paper describes a particular use of the hybrid FEM-DBCI, for the computation of low-frequency electromagnetic fields in open-boundary domains. Once the unbounded free space enclosing the system has been truncated, the FEM is applied to the bounded domain thus obtained, assuming an unknown Dirichlet condition on the truncation boundary. An integral equation is used to express this boundary condition in which the integration surface is selected in the middle of the most external layer of finite elements, very close to the truncation boundary, so that the integral equation becomes quasi-singular. The method is described for the computation of electrostatic fields in 3D and of eddy currents in 2D, but it is also applicable to the solution of other kinds of electromagnetic problems. Comparisons are made with other methods, concluding that FEM-DBCI is competitive with the well-known FEM-BEM and coordinate transformations for what concerns accuracy and computing time.

Free-Standing, Flexible Nanofeatured Polymeric Films Prepared by Spin-Coating and Anodic Polymerization as Electrodes for Supercapacitors

Flexible and self-standing multilayered films made of nanoperforated poly(lactic acid) (PLA) layers separated by anodically polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) conducting layers have been prepared and used as electrodes for supercapacitors. The influence of the external layer has been evaluated by comparing the charge storage capacity of four- and five-layered films in which the external layer is made of PEDOT (PLA/PEDOT/PLA/PEDOT) and nanoperforated PLA (PLA/PEDOT/PLA/PEDOT/PLA), respectively. In spite of the amount of conducting polymer is the same for both four- and five-layered films, they exhibit significant differences. The electrochemical response in terms of electroactivity, areal specific capacitance, stability, and coulombic efficiency was greater for the four-layered electrodes than for the five-layered ones. Furthermore, the response in terms of leakage current and self-discharge was significantly better for the former electrodes than for the latter ones.

Non-Woven Barrier Properties of External Layer for Wound Matrix

Non-woven is commonly used in disposable medical products especially after external surgeries to reduce the infection transfer and improves wound healing. In addition, low its production cost. This study is aimed to engineer the external layer of the wound matrix from non-woven webs and investigation from its barrier performance for fluids leakage, biological odor, and electrostatic charge. The external layer of matrix was suggested to consist of two or three sub-layers from 100% polyester and viscose/polyester (70:30)%. These webs were enhanced by activated carbon (AC) and powdered aloe leaves (A). The final produced samples were evaluated by the radar chart area for the tested properties, in order to determine the best samples produced for the external layer system of the wound matrix. The final samples produced from two and three sub-layers, which were enhanced with powder aloe leaves presented the best performance results, followed by the sample produced from three sub-layers that enhanced with activated carbon, and powdered aloe leaves together. Finally, the activated carbon and powdered aloe leaves that used for enhancing application had a significant effect on the odor absorption with different behavior for each one. The activated carbon absorbed the odor and appeared in its particles. While powdered aloe leaves were absorbed more odor than activated carbon, but it concealment the odor.

Chromogenic Chemodosimeter Based on Capped Silica Particles to Detect Spermine and Spermidine

A new hybrid organic–inorganic material for sensing spermine (Spm) and spermidine (Spd) has been prepared and characterized. The material is based on MCM-41 particles functionalized with an N-hydroxysuccinimide derivative and loaded with Rhodamine 6G. The cargo is kept inside the porous material due to the formation of a double layer of organic matter. The inner layer is covalently bound to the silica particles, while the external layer is formed through hydrogen and hydrophobic interactions. The limits of detection determined by fluorimetric titration are 27 µM and 45 µM for Spm and Spd, respectively. The sensor remains silent in the presence of other biologically important amines and is able to detect Spm and Spd in both aqueous solution and cells.

Towards an Enhanced Tool for Quantifying the Degree of LV Hyper-Trabeculation

Left ventricular non-compaction (LVNC) is defined by an increase of trabeculations in left ventricular (LV) endomyocardium. Although LVNC can be in isolation, an increase in hypertrabeculation often accompanies genetic cardiomyopathies. Current methods for quantification of LV trabeculae have limitations. Several improvements are proposed and implemented to enhance a software tool to quantify the trabeculae degree in the LV myocardium in an accurate and automatic way for a population of patients with genetic cardiomyopathies (QLVTHCI). The software tool is developed and evaluated for a population of 59 patients (470 end-diastole cardiac magnetic resonance images). This tool produces volumes of the compact sector and the trabecular area, the proportion between these volumes, and the left ventricular and trabeculated masses. Substantial enhancements are obtained over the manual process performed by cardiologists, so saving important diagnosis time. The parallelization of the detection of the external layer is proposed to ensure real-time processing of a patient, obtaining speed-ups from 7.5 to 1500 with regard to QLVTHCI and the manual process used traditionally by cardiologists. Comparing the method proposed with the fractal proposal to differentiate LVNC and non-LVNC patients among 27 subjects with previously diagnosed cardiomyopathies, QLVTHCI presents a full diagnostic accuracy, while the fractal criteria achieve 78%. Moreover, QLTVHCI can be installed and integrated in hospitals on request, whereas the high cost of the license of the fractal method per year of this tool has prevented reproducibility by other medical centers.

The Development of a Technology of the Laser-Based Welding of Butt Joints in Composite Tubes

The article presents the results concerning the development of a technology combining laser welding and hybrid surfacing enabling the making of butt joints in composite tube grades Sanicro 38/4L7 and 3R12/4L7. The tests involved the determination of the parameters of the laser welding of tube grade 4L7 and the hybrid surfacing of the external layer of tube grade Sanicro 38 and 3R12. The article also presents the results of the macro and microscopic tests of the joints.

Manoeuvring Bioactive Materials in Dentistry - A Review

Bioactivity refers to bio-inductive activity. The materials which induce such activity are bioactive materials. These materials induce a reaction from living tissue. Bioactive materials have a role in the promotion of the healing process, repair, maintaining the vitality of pulp, etc. The material should be sterile, bacteriostatic and bactericidal in nature. Bioactive materials are used in dentin remineralization, maintaining long-term restorations bonded with cement, and repairing intra-bony lesions. A biomaterial is a substance, external layer or assembly that interconnect with an organic system. Biognosis- an analysis of, structure or uses of biologically generated materials, their mechanisms and processes for the formation of likely products by artificial mechanisms that mimics natural structures. A biomaterial is a substance, external layer or assembly that interconnect with an organic system. These materials differ in their form and function and composition. Bioactive substances function works due to the inauguration of growth initiators and multiple cells. It aids in “growth, immigration, and distinction of odontoblast-like cells producing tissue matrix. Bioactive matrix form an outer layer of an apatite-like substance in association with inorganic phosphate solution. Bioactive materials like calcium hydroxide, mineral trioxide aggregate, biodentin, etc., are commonly used in routine practice. As these materials have multiple purposes, this review focuses to highlight newer materials in the category of bioactivity and their implications in dentistry particularly.

On the specifics of behavior of the sandwich plate composite facing layers under local loading

The problem of a four-point bending of sandwich plates with external layers of a fiber reinforced plastic is considered, the results of numerical and experimental studies are presented. It is shown that in the vicinity of the loading roller, which exerts a local effect on the external layer, there is a strong decrease in the transverse shear secant modulus of fiber reinforced plastic with an increase in the transverse shear strains. The numerical solution of the problem of the plate bending is carried out in a physically and geometrically nonlinear formulation using various relations of the finite element method, two variants of geometrically nonlinear kinematic relations of the equations of the elasticity theory and different variants of the loading process parameter. Along with the classical nonlinear relations, the problem solutions are also constructed on the basis of consistent relations between strains and displacements, the use of which allows one to avoid the appearance occurrence of false bifurcation points. The results of the numerical calculations obtained with different methods and use of different ratios are presented, the analysis of which showed their small difference. It was revealed that the stability loss and failure of the external layers of a sandwich plate occurs due to the stability loss in the nonclassical transverse-shear mode. To determine the ultimate load, which is accompanied with a loss of strength of the external loaded layer, the Tsai-Wu criterion was used. A comparative analysis of the behavior of the plate external layers at different thicknesses and different diameters of the loading roller is carried out. It is shown that the ultimate load is practically not affected by the roller diameter, while the load at which the external layer loses its stability, is very sensitive to a change in its value.