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2021 ◽  
Vol 11 (18) ◽  
pp. 8424
Author(s):  
Songuel Polat ◽  
Alain Tremeau ◽  
Frank Boochs

Successful recycling of electronic waste requires accurate separation of materials such as plastics, PCBs and electronic components on PCBs (capacitors, transistors, etc.). This article therefore proposes a vision approach based on a combination of 3D and HSI data, relying on the mutual support of the datasets to compensate existing weaknesses when using single 3D- and HSI-Sensors. The combined dataset serves as a basis for the extraction of geometric and spectral features. The classification is performed and evaluated based on these extracted features which are exploited through rules. The efficiency of the proposed approach is demonstrated using real electronic waste and leads to convincing results with an overall accuracy (OA) of 98.24%. To illustrate that the addition of 3D data has added value, a comparison is also performed with an SVM classification based only on hyperspectral data.


Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2201
Author(s):  
Pedro A. Martinez ◽  
Enrique A. Navarro ◽  
Jorge Victoria ◽  
Adrian Suarez ◽  
Jose Torres ◽  
...  

Magnetic near-field probes (NFP) represent a suitable tool to measure the magnetic field level from a small electromagnetic interference (EMI) source. This kind of antenna is useful as a magnetic field probe for pre-compliance EMC measurements or debugging tasks since the user can scan a printed circuit board (PCB) looking for locations with strong magnetic fields. When a strong H-field point is found, the designer should check the PCB layout and components placement in that area to detect if this could result in an EMI source. This contribution focuses on analyzing the performance of an easy to build and low-cost H-field NFP designed and manufactured using a standard PCB stack-up. Thereby, the frequency range and sensitivity of the NFP-PCB are analyzed through a Finite Element Method (FEM) simulation model that makes it possible to evaluate its sensibility and effective frequency range. The numerical results obtained with the FEM models are validated against measurements to verify the design and performance of our NFP. The FEM model reproduces the experimental procedure, which is used to evaluate the performance of the NFP in terms of sensitivity by means of the simulated near-field distribution. The NFP-PCB has almost a flat response from 180 MHz to 6 GHz, with an almost perfect concordance between numerical and experimental S21 results. The numerical results show an average transmission loss of −27.9 dB by considering the flat response bandwidth, whereas the experimental one is −29.7 dB. Finally, the designed NFP is compared to two high-quality commercial probes in order to analyze its performance.


2021 ◽  
pp. 2100514
Author(s):  
Chin Huat Joel Lim ◽  
C. S. Suchand Sandeep ◽  
Vadakke Matham Murukeshan ◽  
Young‐Jin Kim

2021 ◽  
Vol 410 ◽  
pp. 692-696
Author(s):  
Alexey N. Shulgin ◽  
Olesya A. Chuprina ◽  
Vasiliy V. Pykhov

One of the main technological criteria affecting the quality of drilling the holes is the correct geometry of a cutting tool and the amount of its wear. The determination of the “critical” amount of a drill wear is possible only through the indirect way, in particular by the presence of the copper foil burrs at the tool output from the printed circuit board, since with the up-to-date degree of integration of micro-assemblies, the main part of the processed holes has the diameter of about 0.6-0.8 mm, and it is quite challenging to determine the tool wear without special equipment, and in conditions of mass production it is almost impossible. A number of industrial experiments with the hard-alloy drills of standard sharpening geometry of various amount of wear was carried out in order to assess the influence of the cutting tool geometry and the amount of wear on the drilling process. To assess the quality of the processed holes, the chip size (Lch), the micro-roughness of the holes (Ra) and the size of the copper foil burrs at the output of the workpieces (Hb) were additionally measured with a specialized precision tool. In total, 1500 holes were drilled at each previously determined operating mode. The “critical” value of the tool blunting, the maximum allowable values of Lch,Ra and Hbwere practically defined in the course of work. On the basis of the conducted experiments, the threshold values of the axial feed speeds for the work of the “worn out” and “blunted” tool were defined. In addition, the general recommendations were formulated for the operator when drilling the foiled fiberglass and eliminating mass defects at printed circuit board manufacture.


Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4960
Author(s):  
Sang-Sun Park ◽  
Na-Young Shin ◽  
Chanmin Lee ◽  
Yukwon Jeon ◽  
Won Seok Chi ◽  
...  

The effect of the Au coated printed circuit board (PCB) as a current collector on the performance of fuel cells is demonstrated. In this study, optimized pulse electroplating was introduced, which was found to be much more effective compared to the direct current (DC) plating for the PCB fabrication based on the passive area from the potentiodynamic polarization scan. Variable electrochemical parameters such as applied potential and frequency for the pulse electroplating method are controlled. Using the polarization tests, the corrosion behavior of the Au coated PCB layer was also observed. From these basic data, the coating methods and electrochemical parameters were systematically controlled to achieve efficient results for direct methanol fuel cells (DMFCs). The stability test for the cell operation indicates that the micro DMFC with the Au coated PCB substrate formed at a frequency of 10 Hz exhibited the highest stability and performance. As a result, the Au coated PCB substrate using pulse electroplating at 1.5 V and 1 kHz can be a promising current collector for portable DMFCs.


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