scholarly journals Novel modular pressure and flow rate balanced microfluidic serial dilution networks on printed circuit boards: Designs, Simulations and Fabrication

2018 ◽  
Author(s):  
Nikolaos Vasilakis ◽  
Konstantinos I. Papadimitriou ◽  
Hywel Morgan ◽  
Themistoklis Prodromakis
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Single Layer ◽  
Unit Cell ◽  
Serial Dilution ◽  
Circuit Board ◽  
Driving Mechanism ◽  
Buffer Solution ◽  
System Architectures ◽  
Printed Circuit

AbstractFast, efficient and more importantly accurate serial dilution is a requirement for many chemical and biological microfluidic-based applications. Over the last decade, a large number of microfluidic devices has been proposed, each demonstrating either a different type of dilution technique or complex system architectures based on various flow source combinations. In this work, a novel serial dilution architecture is demonstrated, implemented on a commercially fabricated printed circuit board (PCB). The proposed single layer, stepwise serial diluter comprises an optimised microfluidic network, where identical dilution ratio per stage can be ensured, either by applying equal pressure or equal flow rates at both inlets. The advantages of the proposed serial diluter are twofold. Firstly, it is structured as a modular unit cell, simplifying the required fluid driving mechanism to a single source for both sample and buffer solution. Thus, this unit cell can be seen as a fundamental microfluidic building block, which can form multistage serial dilution cascades, once combined appropriately with itself or other similar unit cells. Secondly, the serial diluter has been fabricated entirely using commercial PCB technologies, allowing the device to be interfaced with standard electronic components, if more complex miniature point-of-care (PoC) systems are desired, where the small footprint and accuracy of the device is of paramount importance.

Ambient Response Modal Analysis on a CEM-1 Single-Layer Printed Circuit Board

2013 ◽  
Vol 393 ◽  
pp. 683-687
Author(s):  
M. Azhan Anuar ◽  
A.A. Mat Isa ◽  
A.R. Zamri ◽  
M.F.M. Said
Keyword(s):  
Domain Decomposition ◽  
Modal Analysis ◽  
Frequency Domain ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Single Layer ◽  
Circuit Board ◽  
Valuable Insight ◽  
Printed Circuit ◽  
Frequency Domain Decomposition

Since the level of vibration always depends on the natural frequencies of the system, it is important to know the modal parameters of such system to control failure and provide prevention actions. The demand for structurally reliable Printed Circuit Boards (PCB) has increased as more functions are required from electronic products along with less weight and smaller size. This imposes certain limitations and critical requirements. In this paper, investigation on the dynamic characteristics of CEM-1 Single-layer PCB using Operational Modal Analysis (OMA, or often called Output-Only or Ambient Modal analysis), is presented. The Frequency Domain Decomposition (FDD) and Enhanced Frequency Domain Decomposition (EFDD) techniques are applied on the PCB with free-free end condition. Comparison of results between both techniques and also with the result from Experimental Modal Analysis (EMA), will be shown. The understanding on dynamic behaviour of this structure provides valuable insight into the nature of the response and remarkable enhancement of its model, strength and vibration.

scholarly journals Modular Pressure and Flow Rate-Balanced Microfluidic Serial Dilution Networks for Miniaturised Point-of-Care Diagnostic Platforms

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 911
Author(s):  
Nikolaos Vasilakis ◽  
Konstantinos Papadimitriou ◽  
Hywel Morgan ◽  
Themistoklis Prodromakis
Keyword(s):  
Network Architecture ◽  
Point Of Care ◽  
Single Layer ◽  
Unit Cell ◽  
Serial Dilution ◽  
Driving Mechanism ◽  
Buffer Solution ◽  
Unit Cells ◽  
And Performance ◽  
Diagnostic Applications

Fast, efficient and more importantly accurate serial dilution is a necessary requirement for most biochemical microfluidic-based quantitative diagnostic applications. Over the last two decades, a multitude of microfluidic devices has been proposed, each one demonstrating either a different type of dilution technique or complex system architecture based on various flow source and valving combinations. In this work, a novel serial dilution network architecture is demonstrated, implemented on two entirely different substrates for validation and performance characterisation. The single layer, stepwise serial diluter comprises an optimised microfluidic network, where identical dilution ratios per stage are ensured, either by applying equal pressure or equal flow rates at both inlets. The advantages of this serial diluter are twofold: Firstly, it is structured as a modular unit cell, simplifying the required fluid driving mechanism to a single source for both sample and buffer solution. Thus, this unit cell can be used as a fundamental microfluidic building block, forming multistage serial dilution cascades, once combined appropriately with itself or other similar unit cells. Secondly, the serial diluter can tolerate the inevitable flow source fluctuations, ensuring constant dilution ratios without the need to employ damping mechanisms, making it ideal for Point of Care (PoC) platforms. Proof-of-concept experiments with glucose have demonstrated good agreement between simulations and measurements, highlighting the validity of our serial diluter.

Dielectric Breakdown in Printed Circuit Boards at Elevated Temperatures

1996 ◽  
Author(s):  
P. Singh ◽  
G.T. Galyon ◽  
J. Obrzut ◽  
W.A. Alpaugh
Keyword(s):  
Experimental Data ◽  
Thermal Degradation ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Elevated Temperatures ◽  
Dielectric Breakdown ◽  
Circuit Board ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Data Matching

Abstract A time delayed dielectric breakdown in printed circuit boards, operating at temperatures below the epoxy resin insulation thermo-electrical limits, is reported. The safe temperature-voltage operating regime was estimated and related to the glass-rubber transition (To) of printed circuit board dielectric. The TG was measured using DSC and compared with that determined from electrical conductivity of the laminate in the glassy and rubbery state. A failure model was developed and fitted to the experimental data matching a localized thermal degradation of the dielectric and time dependency. The model is based on localized heating of an insulation resistance defect that under certain voltage bias can exceed the TG, thus, initiating thermal degradation of the resin. The model agrees well with the experimental data and indicates that the failure rate and truncation time beyond which the probability of failure becomes insignificant, decreases with increasing glass-rubber transition temperature.

scholarly journals Estimating Recycling Return of Integrated Circuits Using Computer Vision on Printed Circuit Boards

2021 ◽  
Vol 11 (6) ◽  
pp. 2808
Author(s):  
Leandro H. de S. Silva ◽  
Agostinho A. F. Júnior ◽  
George O. A. Azevedo ◽  
Sergio C. Oliveira ◽  
Bruno J. T. Fernandes
Keyword(s):  
Integrated Circuits ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Electronic Waste ◽  
Decision Criterion ◽  
Economic Feasibility ◽  
Electronic Equipment ◽  
Circuit Board ◽  
Mechanical Recycling ◽  
Printed Circuit

The technological growth of the last decades has brought many improvements in daily life, but also concerns on how to deal with electronic waste. Electrical and electronic equipment waste is the fastest-growing rate in the industrialized world. One of the elements of electronic equipment is the printed circuit board (PCB) and almost every electronic equipment has a PCB inside it. While waste PCB (WPCB) recycling may result in the recovery of potentially precious materials and the reuse of some components, it is a challenging task because its composition diversity requires a cautious pre-processing stage to achieve optimal recycling outcomes. Our research focused on proposing a method to evaluate the economic feasibility of recycling integrated circuits (ICs) from WPCB. The proposed method can help decide whether to dismantle a separate WPCB before the physical or mechanical recycling process and consists of estimating the IC area from a WPCB, calculating the IC’s weight using surface density, and estimating how much metal can be recovered by recycling those ICs. To estimate the IC area in a WPCB, we used a state-of-the-art object detection deep learning model (YOLO) and the PCB DSLR image dataset to detect the WPCB’s ICs. Regarding IC detection, the best result was obtained with the partitioned analysis of each image through a sliding window, thus creating new images of smaller dimensions, reaching 86.77% mAP. As a final result, we estimate that the Deep PCB Dataset has a total of 1079.18 g of ICs, from which it would be possible to recover at least 909.94 g of metals and silicon elements from all WPCBs’ ICs. Since there is a high variability in the compositions of WPCBs, it is possible to calculate the gross income for each WPCB and use it as a decision criterion for the type of pre-processing.

Evaluation of new technologies and materials for printed circuit boards with improved heat dissipation properties

Circuit World ◽  
2016 ◽  
Vol 42 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Michal Baszynski ◽  
Edward Ramotowski ◽  
Dariusz Ostaszewski ◽  
Tomasz Klej ◽  
Mariusz Wojcik ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Printed Circuit Boards ◽  
Heat Dissipation ◽  
Printed Circuit Board ◽  
New Technologies ◽  
Electronic Device ◽  
Circuit Board ◽  
New Materials ◽  
Content Type ◽  
Printed Circuit

Purpose – The purpose of this paper is to evaluate thermal properties of printed circuit board (PCB) made with use of new materials and technologies. Design/methodology/approach – Four PCBs with the same layout but made with use of different materials and technologies have been investigated using thermal camera to compare their thermal properties. Findings – The results show how important the thermal properties of PCBs are for providing effective heat dissipation, and how a simple alteration to the design can help to improve the thermal performance of electronic device. Proper layout, new materials and technologies of PCB manufacturing can significantly reduce the temperature of electronic components resulting in higher reliability of electronic and power electronic devices. Originality/value – This paper shows the advantages of new technologies and materials in PCB thermal management.

scholarly journals A Study on the Radiated Susceptibility of Printed Circuit Boards and the Effects of Via Fencing

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 539
Author(s):  
Ryan P. Tortorich ◽  
William Morell ◽  
Elizabeth Reiner ◽  
William Bouillon ◽  
Jin-Woo Choi
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Ground Plane ◽  
Circuit Board ◽  
Electronic Systems ◽  
Coupling Mechanism ◽  
Electromagnetic Modeling ◽  
Printed Circuit ◽  
Edge Radiation ◽  
Area Of Concern

Because modern electronic systems are likely to be exposed to high intensity radiated fields (HIRF) environments, there is growing interest in understanding how electronic systems are affected by such environments. Backdoor coupling in particular is an area of concern for all electronics, but there is limited understanding about the mechanisms behind backdoor coupling. In this work, we present a study on printed circuit board (PCB) backdoor coupling and the effects of via fencing. Existing work focuses on ideal stackups and indicates that edge radiation is significantly reduced by via fencing. In this study, both full wave electromagnetic modeling and experimental verification are used to investigate both ideal and practical PCB stackups. In the ideal scenario, we find that via fencing substantially reduces coupling, which is consistent with prior work on emissions. In the practical scenario, we incorporate component footprints and traces which naturally introduce openings in the top ground plane. Both simulation and experimental data indicate that via fencing in the practical scenario does not substantially mitigate coupling, suggesting that PCB edge coupling is not the dominant coupling mechanism, even at varying angles of incidence and polarization.

Hierarchical pyramidal subsampling in deep convolutional networks for visual pattern recognition

2021 ◽  
Author(s):  
A. E. Averyanikhin ◽  
A. I. Vlasov ◽  
E. V. Evdokimova
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Flaw Detection ◽  
Input Image ◽  
Circuit Board ◽  
Digital Data ◽  
Deep Convolutional Neural Networks ◽  
Size Scale ◽  
Printed Circuit ◽  
Convolutional Networks

The main problem of known deep convolutional neural networks (CNN) is that they require a fixed-size input image. This requirement is “artificial” and can reduce recognition accuracy for images or its parts of arbitrary size/scale. The paper proposes a strategy of combining “hierarchical pyramidal subselection” to eliminate the above restriction. The structure of the neural network using the proposed combining strategy allows the generation of prediction regardless of the size/scale of the original image, and also improves the accuracy of recognition. Features of application of CNN for identification and recognition of defects of conducting pattern of printed circuit board blanks have been considered. Features of defects of conductive pattern of printed circuit board blanks have been briefly discussed. The invention proposes the use of artificial CNN, which have advantages in speed and accuracy in solving problems of object recognition on images relative to existing methods. The focus is on the architecture of CNN using hierarchical pyramidal subselection. Capabilities of application of CNN for recognition of defects of conducting pattern of printed circuit board blanks have been shown. Proposed method of hierarchical pyramidal subselection in deep convolutional networks has been implemented in software complex, which allows processing digital data of photographs of conducting pattern of printed circuit boards, in particular during their flaw detection, and can be used for localization of existing defects of conducting pattern. The conclusion draws the possibilities of using methods and means of image processing in flaw detection of radio-electronic equipment and instruments

scholarly journals Optimization Studies on Recovery of Metals from Printed Circuit Board Waste

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
P. Sivakumar ◽  
D. Prabhakaran ◽  
M. Thirumarimurugan
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Lead Nitrate ◽  
Acid Leaching ◽  
Circuit Board ◽  
Copper Recovery ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Electrode Combination ◽  
Lead Metal

The aim of the study was to recover copper and lead metal from waste printed circuit boards (PCBs). The electrowinning method is found to be an effective recycling process to recover copper and lead metal from printed circuit board wastes. In order to simplify the process with affordable equipment, a simple ammonical leaching operation method was adopted. The selected PCBs were incinerated into fine ash powder at 500°C for 1 hour in the pyrolysis reactor. Then, the fine ash powder was subjected to acid-leaching process to recover the metals with varying conditions like acid-base concentration, electrode combination, and leaching time. The relative electrolysis solution of 0.1 M lead nitrate for lead and 0.1 M copper sulphate for copper was used to extract metals from PCBs at room temperature. The amount of lead and copper extracted from the process was determined by an atomic absorption spectrophotometer, and results found were 73.29% and 82.17%, respectively. Further, the optimum conditions for the recovery of metals were determined by using RSM software. The results showed that the percentage of lead and copper recovery were 78.25% and 89.1% should be 4 hrs 10 A/dm2.

scholarly journals POSIBILITY OF CREATING A PRINTED SINGLE-LAYER TRANSREFLECTOR WITH INCREASED PHASE EFFICIENCY

2019 ◽  
pp. 139-145
Author(s):  
A. N. Mikhailov
Keyword(s):  
Printed Circuit Board ◽  
Single Layer ◽  
Circuit Board ◽  
Horizontal Polarization ◽  
Radiation Characteristics ◽  
Printed Circuit ◽  
W Band ◽  
New Type ◽  
Reflectarray Antenna ◽  
Geometrical Dimensions

A new type of single‑layer transrefleсtor structure based on microstrip reflective antenna array is described. The developed  device is a single‑layer printed circuit board on one side of which a system of printed reflectors is located, and on the other is  a polarization structure consisting of parallel metal conductors, in contrast to a microstrip reflectarray antenna. The shape and  geometrical dimensions of printed reflectors arranged in a rectangular or hexagonal (triangular) pattern are chosen in such a way  that they transform a spherical front of an incident vertically polarized electromagnetic wave into a flat front of reflected wave. In  the case of irradiation of the developed transreflector with a horizontal polarization wave, the printed structure makes minimal  electromagnetic energy loss during its passage. The results of characteristics modeling (including phase curves) of an element  of the reflective lattice in the W‑band for different angles of incidence of the wave on the planar structure under study are given.  Based on the results obtained, the sizes of the reflective elements of the transreflector, which provide for the correction of the  incident wave with the necessary phase discrete, are determined and an electrodynamic model of the transreflector antenna is  built. The simulation of the main radiation characteristics of the antenna with the developed single‑layer transreflector was carried  out.

scholarly journals A model for the reflection of terahertz signals from printed circuit board surfaces

2018 ◽  
Vol 10 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Alexander Fricke ◽  
Mounir Achir ◽  
Philippe Le Bars ◽  
Thomas Kürner
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Simulated Annealing Algorithm ◽  
Specular Reflection ◽  
Circuit Board ◽  
Network Analyzer ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Propagation Modeling ◽  
Annealing Algorithm

AbstractBased on vector network analyzer Measurements, a model for the specular reflection behavior of printed circuit boards in the Terahertz range has been derived. It has been calibrated to suit the behavior of the measurements using a simulated annealing algorithm. The model has been tailored for integration to ray-tracing-based propagation modeling.

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