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Sample records for circuit board pcb

  1. Waste Printed Circuit Board (PCB) Recycling Techniques.

    PubMed

    Ning, Chao; Lin, Carol Sze Ki; Hui, David Chi Wai; McKay, Gordon

    2017-04-01

    With the development of technologies and the change of consumer attitudes, the amount of waste electrical and electronic equipment (WEEE) is increasing annually. As the core part of WEEE, the waste printed circuit board (WPCB) is a dangerous waste but at the same time a rich resource for various kinds of materials. In this work, various WPCB treatment methods as well as WPCB recycling techniques divided into direct treatment (landfill and incineration), primitive recycling technology (pyrometallurgy, hydrometallurgy, biometallurgy and primitive full recovery of NMF-non metallic fraction), and advanced recycling technology (mechanical separation, direct use and modification of NMF) are reviewed and analyzed based on their advantages and disadvantages. Also, the evaluation criteria are discussed including economic, environmental, and gate-to-market ability. This review indicates the future research direction of WPCB recycling should focus on a combination of several techniques or in series recycling to maximize the benefits of process.

  2. Liberation characteristic and physical separation of printed circuit board (PCB).

    PubMed

    Guo, Chao; Wang, Hui; Liang, Wei; Fu, Jiangang; Yi, Xin

    2011-01-01

    Recycling of printed circuit board (PCB) is an important subject and to which increasing attention is paid, both in treatment of waste as well as recovery of valuable material terms. Precede physical and mechanical method, a good liberation is the premise to further separation. In this study, two-step crushing process is employed, and standard sieve is applied to screen crushed material to different size fractions, moreover, the liberation situation and particles shape in different size are observed. Then metal of the PCB is separated by physical methods, including pneumatic separation, electrostatic separation and magnetic separation, and major metal contents are characterized by inductively coupled plasma emission spectrometry (ICP-AES). Results show that the metal and nonmetal particles of PCB are dissociated completely under the crush size 0.6mm; metal is mainly enriched in the four size fractions between 0.15 and 1.25 mm; relatively, pneumatic separation is suitable for 0.6-0.9 mm size fraction, while the electrostatic separation is suitable for three size fractions that are 0.15-0.3mm, 0.3-0.6mm and 0.9-1.25 mm. The whole process that involves crushing, electrostatic and magnetic separation has formed a closed cycle that can return material and provide salable product.

  3. Integrated Printed Circuit Board (PCB) Active Cooling With Piezoelectric Actuator

    DTIC Science & Technology

    2012-09-01

    or nichrome (NiCr) resistors which are fabricated on the surface of a PCB substrate. The heater coil has an area of 0.25 centimeters squared and a...control the heater, a Pulse Width Modulated (PWM) signal (generated by the DAQ board) controls a constant current source to a transistor between the...Cycle Heater Voltage Heater Lowpass Filter Current Source 9 There are three RTDs embedded in the unit under test. To make a measurement, constant

  4. Printed Circuit Board Design (PCB) with HDL Designer

    NASA Technical Reports Server (NTRS)

    Winkert, Thomas K.; LaFourcade, Teresa

    2004-01-01

    Contents include the following: PCB design with HDL designer, design process and schematic capture - symbols and diagrams: 1. Motivation: time savings, money savings, simplicity. 2. Approach: use single tool PCB for FPGA design, more FPGA designs than PCB designers. 3. Use HDL designer for schematic capture.

  5. Voltage injection and readout method for PCB (printed circuit board) testing

    NASA Astrophysics Data System (ADS)

    Zentai, G.

    2006-03-01

    The main objectives of PCB (Printed Circuit Board) testing are to find short and open circuits before attaching components to the PCB. An electrostatic imaging technique was described earlier by Zentai at al. in the SPIE-NDE 2003 conference and has been accepted as a US patent. The main goal of that application was to test the PCBs quickly and efficiently without attaching test probes to each of the traces. It was achieved with the proposed technique. However, we still had to use test probe matrix for generating test signals in the traces and the detected signal was greatly reduced in reference to the test signal because of capacitive sharing of charges caused by the insulator layer placed between the PCB and the TFT sensor array. A new idea has been developed for applying voltages to the traces with an addressing matrix, different from the pin addressing one. This matrix is similar to the readout matrix that the previous method referenced to, but instead of readout circuits, driver circuits are connected to the pixels to apply voltages to them. The printed circuit board is laid on top of the array, but rather than using an insulator foil, a directional conducting foam (rubber) layer can be applied between the excitation matrix (array) and the PCB. We get direct coupling of the matrix pixels to the PCB traces and no connection between neighboring pixels (traces) using the directional conductive layer, which conducts only in z direction and not in x (and y) direction. Therefore, by addressing each pixel separately, which is easy to do by software, we get an addressable voltage (pulse) injector matrix. The same directional conducting foam coupling can also be used for reading out the image of traces. Because the capacitive coupling is eliminated, the detected signal increases and so the sensitivity.

  6. Two-step bioleaching of copper and gold from discarded printed circuit boards (PCB).

    PubMed

    Işıldar, Arda; van de Vossenberg, Jack; Rene, Eldon R; van Hullebusch, Eric D; Lens, Piet N L

    2016-11-01

    An effective strategy for environmentally sound biological recovery of copper and gold from discarded printed circuit boards (PCB) in a two-step bioleaching process was experimented. In the first step, chemolithotrophic acidophilic Acidithiobacillus ferrivorans and Acidithiobacillus thiooxidans were used. In the second step, cyanide-producing heterotrophic Pseudomonas fluorescens and Pseudomonas putida were used. Results showed that at a 1% pulp density (10g/L PCB concentration), 98.4% of the copper was bioleached by a mixture of A. ferrivorans and A. thiooxidans at pH 1.0-1.6 and ambient temperature (23±2°C) in 7days. A pure culture of P. putida (strain WCS361) produced 21.5 (±1.5)mg/L cyanide with 10g/L glycine as the substrate. This gold complexing agent was used in the subsequent bioleaching step using the Cu-leached (by A. ferrivorans and A. thiooxidans) PCB material, 44.0% of the gold was mobilized in alkaline conditions at pH 7.3-8.6, and 30°C in 2days. This study provided a proof-of-concept of a two-step approach in metal bioleaching from PCB, by bacterially produced lixiviants.

  7. Optical printed circuit board (O-PCB) and VLSI photonic integrated circuits: visions, challenges, and progresses

    NASA Astrophysics Data System (ADS)

    Lee, El-Hang; Lee, S. G.; O, B. H.; Park, S. G.; Noh, H. S.; Kim, K. H.; Song, S. H.

    2006-09-01

    A collective overview and review is presented on the original work conducted on the theory, design, fabrication, and in-tegration of micro/nano-scale optical wires and photonic devices for applications in a newly-conceived photonic systems called "optical printed circuit board" (O-PCBs) and "VLSI photonic integrated circuits" (VLSI-PIC). These are aimed for compact, high-speed, multi-functional, intelligent, light-weight, low-energy and environmentally friendly, low-cost, and high-volume applications to complement or surpass the capabilities of electrical PCBs (E-PCBs) and/or VLSI electronic integrated circuit (VLSI-IC) systems. These consist of 2-dimensional or 3-dimensional planar arrays of micro/nano-optical wires and circuits to perform the functions of all-optical sensing, storing, transporting, processing, switching, routing and distributing optical signals on flat modular boards or substrates. The integrated optical devices include micro/nano-scale waveguides, lasers, detectors, switches, sensors, directional couplers, multi-mode interference devices, ring-resonators, photonic crystal devices, plasmonic devices, and quantum devices, made of polymer, silicon and other semiconductor materials. For VLSI photonic integration, photonic crystals and plasmonic structures have been used. Scientific and technological issues concerning the processes of miniaturization, interconnection and integration of these systems as applicable to board-to-board, chip-to-chip, and intra-chip integration, are discussed along with applications for future computers, telecommunications, and sensor-systems. Visions and challenges toward these goals are also discussed.

  8. Improved version of the printed circuit board (PCB) modular multi-channel microdrive for extracellular electrophysiological recordings.

    PubMed

    Tóth, Attila; Petykó, Zoltán; Máthé, Kálmán; Szabó, Imre; Czurkó, András

    2007-01-15

    The modular multi-channel PCB microdrive was described some years ago, since then several improvements were introduced while using these drives. Utilizing several years of experience with the original PCB microdrive we redesigned it to improve its stability and usability. The application of the printed circuit board technology and the extensive use of flexible fused silica capillaries for fabrication of the microdrive are described in detail. The improved design led to a low cost and light-weight multi-channel microdrive with outstanding modularity for extracellular field, single unit or multiunit tetrode recording up to 64/128 channels.

  9. Ultrasonic recovery of copper and iron through the simultaneous utilization of Printed Circuit Boards (PCB) spent acid etching solution and PCB waste sludge.

    PubMed

    Huang, Zhiyuan; Xie, Fengchun; Ma, Yang

    2011-01-15

    A method was developed to recover the copper and iron from Printed Circuit Boards (PCB) manufacturing generated spent acid etching solution and waste sludge with ultrasonic energy at laboratory scale. It demonstrated that copper-containing PCB spent etching solution could be utilized as a leaching solution to leach copper from copper contained PCB waste sludge. It also indicated that lime could be used as an alkaline precipitating agent in this method to precipitate iron from the mixture of acidic PCB spent etching solution and waste sludge. This method provided an effective technique for the recovery of copper and iron through simultaneous use of PCB spent acid solution and waste sludge. The leaching rates of copper and iron enhanced with ultrasound energy were reached at 93.76% and 2.07% respectively and effectively separated copper from iron. Followed by applying lime to precipitate copper from the mixture of leachate and rinsing water produced by the copper and iron separation, about 99.99% and 1.29% of soluble copper and calcium were settled as the solids respectively. Furthermore the settled copper could be made as commercial rate copper. The process performance parameters studied were pH, ultrasonic power, and temperature. This method provided a simple and reliable technique to recover copper and iron from waste streams generated by PCB manufacturing, and would significantly reduce the cost of chemicals used in the recovery. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. PVC-based composite material containing recycled non-metallic printed circuit board (PCB) powders.

    PubMed

    Wang, Xinjie; Guo, Yuwen; Liu, Jingyang; Qiao, Qi; Liang, Jijun

    2010-12-01

    The study is directed to the use of non-metallic powders obtained from comminuted recycled paper-based printed circuit boards (PCBs) as an additive to polyvinyl chloride (PVC) substrate. The physical properties of the non-metallic PCB (NMPCB) powders were measured, and the morphological, mechanical and thermal properties of the NMPCB/PVC composite material were investigated. The results show that recycled NMPCB powders, when added below a threshold, tended to increase the tensile strength and bending strength of PVC. When 20 wt% NMPCB powders (relative to the substrate PVC) of an average diameter of 0.08 mm were added, the composite tensile strength and bending strength reached 22.6 MPa and 39.83 MPa, respectively, representing 107.2% and 123.1% improvement over pure PVC. The elongation at break of the composite material reached 151.94% of that of pure PVC, while the Vicat softening temperature of the composite material did not increase significantly compared to the pure PVC. The above results suggest that paper-based NMPCB powders, when used at appropriate amounts, can be effective for toughening PVC. Thus, this study suggests a new route for reusing paper-based NMPCB, which may have a significant beneficial environmental impact.

  11. Thermal eddy current testing of metallization quality of printed circuit boards (PCB)

    NASA Astrophysics Data System (ADS)

    Savushkin, D. G.; Polyahov, M. Y.; Chernov, L. A.

    2000-05-01

    Today the fissile thermal control methods are used often enough to evaluate the metallization quality of printed circuit boards. However, it is necessary to note that the existing difficulties while exciting a non-steady thermal wave. There was offered the thermal input, which allows us to supply heat through the upper edge of a metallizing tube and to register parameters of thermal disturbance from the opposite side. The thermal input represents a hollow metal cone where the thermal disturbance is suggested to be effectuated by eddy currents induced by a coil situated above the thermal input. The agitating current is a kind of radio pulse with a high frequency filling. The field frequency, thickness and the electromagnetic characteristics of the thermal input were selected so that the field couldn't propagate into space beneath the thermal input. It is possible to evaluate some parameters of the metallizing tube registering from the other side of the printed circuit board the thermal disturbance parameters (e.g. the arrival time of maximum and amplitude). The numerical calculations were made with a specially developed software with the purpose of obtaining the dependence of the arrival time of maximum and the thermal disturbance amplitude upon a printed circuit board metallization layer, the hole diameter, the board thickness, the metallization tube conductivity, the contact pad diameter. The heat exchange with the board material was not taken into account when making calculations because the thermal disturbance propagation time along the metallization tube is too short and this assumption does not make a considerable error.

  12. Investigation of multilayer printed circuit board (PCB) film warpage using viscoelastic properties measured by a vibration test

    NASA Astrophysics Data System (ADS)

    Joo, Sung-Jun; Park, Buhm; Kim, Do-Hyoung; Kwak, Dong-Ok; Song, In-Sang; Park, Junhong; Kim, Hak-Sung

    2015-03-01

    Woven glass fabric/BT (bismaleimide triazine) composite laminate (BT core), copper (Cu), and photoimageable solder resist (PSR) are the most widely used materials for semiconductors in electronic devices. Among these materials, BT core and PSR contain polymeric materials that exhibit viscoelastic behavior. For this reason, these materials are considered to have time- and temperature-dependent moduli during warpage analysis. However, the thin geometry of multilayer printed circuit board (PCB) film makes it difficult to identify viscoelastic characteristics. In this work, a vibration test method was proposed for measuring the viscoelastic properties of a multilayer PCB film at different temperatures. The beam-shaped specimens, composed of a BT core, Cu laminated on a BT core, and PSR and Cu laminated on a BT core, were used in the vibration test. The frequency-dependent variation of the complex bending stiffness was determined using a transfer function method. The storage modulus (E‧) of the BT core, Cu, and PSR as a function of temperature and frequency were obtained, and their temperature-dependent variation was identified. The obtained properties were fitted using a viscoelastic model for the BT core and the PSR, and a linear elastic model for the Cu. Warpage of a line pattern specimen due to temperature variation was measured using a shadow Moiré analysis and compared to predictions using a finite element model. The results provide information on the mechanism of warpage, especially warpage due to temperature-dependent variation in viscoelastic properties.

  13. Disassembly and physical separation of electric/electronic components layered in printed circuit boards (PCB).

    PubMed

    Lee, Jaeryeong; Kim, Youngjin; Lee, Jae-chun

    2012-11-30

    Although printed circuit boards (PCBs) contain various elements, only the major elements (i.e., those with content levels in wt% or over grade) of and precious metals (e.g., Ag, Au, and platinum groups) contained within PCBs can be recycled. To recover other elements from PCBs, the PCBs should be properly disassembled as the first step of the recycling process. The recovery of these other elements would be beneficial for efforts to conserve scarce resources, reuse electric/electronic components (EECs), and eliminate environmental problems. This paper examines the disassembly of EECs from wasted PCBs (WPCBs) and the physical separation of these EECs using a self-designed disassembling apparatus and a 3-step separation process of sieving, magnetic separation, and dense medium separation. The disassembling efficiencies were evaluated by using the ratio of grinding area (E(area)) and the weight ratio of the detached EECs (E(weight)). In the disassembly treatment, these efficiencies were improved with an increase of grinder speed and grinder height. 97.7% (E(area)) and 98% (E(weight)) could be accomplished ultimately by 3 repetitive treatments at a grinder speed of 5500 rpm and a grinder height of 1.5mm. Through a series of physical separations, most groups of the EECs (except for the diode, transistor, and IC chip groups) could be sorted at a relatively high separation efficiency of about 75% or more. To evaluate the separation efficiency with regard to the elemental composition, the distribution ratio (R(dis)) and the concentration ratio (R(conc)) were used. 15 elements could be separated with the highest R(dis) and R(conc) in the same separated division. This result implies that the recyclability of the elements is highly feasible, even though the initial content in EECs is lower than several tens of mg/kg.

  14. Nonlinear dynamic response of a 'flexible-and-heavy' printed circuit board (PCB) to an impact load applied to its support contour

    NASA Astrophysics Data System (ADS)

    Suhir, E.; Vujosevic, M.; Reinikainen, T.

    2009-02-01

    Based on the developed simple and physically meaningful analytical ('mathematical') stress model, we evaluate some major parameters (amplitude, frequency, maximum acceleration, stresses and strains) of the response of a 'flexible-and-heavy' square simply supported printed circuit board (PCB) to an impact drop load applied to its support contour. The analysis is restricted to the first mode of vibrations and is carried out in application to the PCB design employed in an advanced accelerated test setup (test vehicle). This setup is aimed at the assessment of the performance, in accelerated test conditions on the board level, of packaging materials (and, first of all, BGA solder joint interconnections) subjected to dynamic (drop or shock) loading. It is anticipated that heavy masses could be mounted on the PCB to accelerate its dynamic response to an impact load. These masses are expected to be small in size, so that while changing the total mass of the board and generating significant inertia forces, they do not affect the board's flexural rigidity or its stiffness with respect to the in-plane loading. The PCB's contour is considered non-deformable, which is indeed the case in many practical situations. This circumstance, if the drop height and/or the induced inertia forces are significant, leads to elevated in-plane ('membrane') stresses in the PCB and, as a result of that, to the nonlinear response of the board to the impact load: the relationship between the magnitude of the load (determined by the initial impact velocity) and the induced PCB deflections becomes geometrically nonlinear, with a rigid cubic characteristic of the restoring force. The carried out numerical example, although reflects the characteristics of the PCB and loading conditions in an actual experimental setup, is merely an illustration of the general concept and is intended to demonstrate the abilities of the suggested method. Predictions based on this method agree well with the finite element

  15. Document Template for Printed Circuit Board Layout

    SciTech Connect

    Anderson, J.T.; /Fermilab

    1998-01-01

    The purpose of this document is to list the information that may be required to properly specify a printed circuit board (PCB) design. You must provide sufficient information to the PCB layout vendor such that they can quote accurately and design the PCB that you need. Use the following information as a guide to write your specification. Include as much of it as is necessary to get the PCB design that you want.

  16. Integration of micro/nano-scale optical waveguide arrays and devices for optical printed circuit board (O-PCB) and VLSI photonic application

    NASA Astrophysics Data System (ADS)

    Lee, El-Hang; Lee, S. G.; O, B. H.; Park, S. G.; Kim, K. H.; Song, S. H.; Kim, H. S.

    2005-08-01

    We report on the design, fabrication and integration of micro/nano-scale optical waveguide arrays and devices for optical printed circuit board (O-PCB) and VLSI photonic applications. The O-PCBs perform the functions of transporting, switching, routing and distributing optical signals on flat modular boards or chips in a manner similar to the electrical printed circuit boards (E-PCBs). The photonic devices include microlasers, microlenses, micro-reflectors, couplers, arrayed waveguide grating structures, multimode interference (MMI) devices and photodetectors. For VLSI micro/nano-photonics we used photonic crystals and plasmonic metal waveguide structures. We also describe device characterization using near filed scanning microscopy. We examine the scientific and technological issues concerning the miniaturization, interconnection, and integration of photonic devices, circuits and systems in micron or submicron scale. In miniaturization, the issues include size effect, proximity effect, energy confinement effect, microcavitiy effect, single photon effect, optical interference effect, high field effect, nonlinear effect, noise effect, quantum optical effect, and chaotic noise effect. In interconnection, the issues include homogeneous interconnection (between identical devices) and heterogeneous interconnection (non-identical devices). In integration, the issues of interfacing same kind of devices, two different kinds of devices, and several or many different kinds of devices are addressed. The discussion includes the nano-scale electron beam system and techniques to characterize nano-scale structures.

  17. Laser direct imaging of the printed electrical circuits on PCB

    NASA Astrophysics Data System (ADS)

    Barbucha, R.; Kocik, M.; Mizeraczyk, J.; Kozioł, G.; Borecki, J.

    2005-09-01

    The increasing demands for miniaturization and better functionality of electronic components and devices have a significant effect on the requirements facing the Printed Circuit Board (PCB) industry. PCB manufactures are driving for producing high density interconnect (HDI) boards at significantly reduced cost and reduced implementation time. The interconnection complexity of the PCB is still growing and today calls for 50/50 μm or 25/25 μm technology are real. Imaging of HDI boards poses a rapid increasing challenge on PCB manufactures due to line width and space getting smaller and mainly to tighter registration requirements. Existing technologies are unable to offer the acceptable solution. Nowadays the Laser Direct Imaging (LDI) technology is considered as an answer for these challenges. LDI is a process of imaging circuitry pattern directly on the PCB without the use of a phototool. The exposure of the photo-sensitive resist is carried out using a laser beam that is scanned across photoresist surface and switched on and off by means of a computer control system according to the electrical circuit pattern. Usually the laser used in the LDI generates the UV line, which is suitable for the commonly available photoresists. In this paper we present an introduction to LDI technology as well as an experiment consisted in an attempt to use a UV Nd:YAG laser (λ=355 nm) for direct imaging of conductive pattern on the PCB covered by photosensitive resist.

  18. Printed circuit board industry.

    PubMed

    LaDou, Joseph

    2006-05-01

    The printed circuit board is the platform upon which microelectronic components such as semiconductor chips and capacitors are mounted. It provides the electrical interconnections between components and is found in virtually all electronics products. Once considered low technology, the printed circuit board is evolving into a high-technology product. Printed circuit board manufacturing is highly complicated, requiring large equipment investments and over 50 process steps. Many of the high-speed, miniaturized printed circuit boards are now manufactured in cleanrooms with the same health and safety problems posed by other microelectronics manufacturing. Asia produces three-fourths of the world's printed circuit boards. In Asian countries, glycol ethers are the major solvents used in the printed circuit board industry. Large quantities of hazardous chemicals such as formaldehyde, dimethylformamide, and lead are used by the printed circuit board industry. For decades, chemically intensive and often sloppy manufacturing processes exposed tens of thousands of workers to a large number of chemicals that are now known to be reproductive toxicants and carcinogens. The printed circuit board industry has exposed workers to high doses of toxic metals, solvents, acids, and photolithographic chemicals. Only recently has there been any serious effort to diminish the quantity of lead distributed worldwide by the printed circuit board industry. Billions of electronics products have been discarded in every region of the world. This paper summarizes recent regulatory and enforcement efforts.

  19. Printed Circuit Board Inspection.

    DTIC Science & Technology

    1981-11-25

    8217, but copper is etched off a smoothly plated board to form the ’printed circuit.’ The etching, as the name implies, leaves a three- 6 Figure 3-2...e.g., dust on the light- plate used to transfer the board design from the artwork negative). The information output must be verifiable -. if only to...Carnegie-Mellon University 00 PRINTED CIRCUIT BOARD INSPECTION W ~Robert Thibadeau -= The Robotics Institute Carnegie-Mellon University Pittsburgh

  20. Dielectric Circuit Board Bonding.

    DTIC Science & Technology

    circuit boards to form subassemblies and the bonding of subassemblies together. The finished circuit may include a bonded-in ground plate of copper...The patent application describes a method and apparatus for bonding of dielectric circuit boards for microwave use, the bonding together of several...wire cloth or the like and may include through- plate holes. The technique includes the build-up of thin films to provide strength, toughness and

  1. Chip- and board-level optical interconnections using rigid flexible optical electrical printed circuit boards.

    PubMed

    Hwang, S H; Lee, W-J; Lim, J W; Jung, K Y; Cha, K S; Rho, B S

    2008-05-26

    A new optical interconnection scheme based on a rigid flexible optical electrical printed circuit board (RFOE-PCB) is suggested. The easily installed RFOE-PCB can be universally applied for both chip- and board-level optical interconnections. This letter describes the detailed fabrication process, optical properties, and heat-resisting property of the RFOE-PCB. The fabricated RFOE-PCB was also successfully demonstrated with a 2.5-Gb/s data transmission through a 45 degrees-ended optical waveguide embedded in the RFOE-PCB.

  2. Microfluidic networks embedded in a printed circuit board

    NASA Astrophysics Data System (ADS)

    Dong, Liangwei; Hu, Yueli

    2017-07-01

    In order to improve the robustness of microfluidic networks in printed circuit board (PCB)-based microfluidic platforms, a new method was presented. A pattern in a PCB was formed using hollowed-out technology. Polydimethylsiloxane was partly filled in the hollowed-out fields after mounting an adhesive tape on the bottom of the PCB, and solidified in an oven. Then, microfluidic networks were built using soft lithography technology. Microfluidic transportation and dilution operations were demonstrated using the fabricated microfluidic platform. Results show that this method can embed microfluidic networks into a PCB, and microfluidic operations can be implemented in the microfluidic networks embedded into the PCB.

  3. Analysis of Multilayered Printed Circuit Boards using Computed Tomography

    DTIC Science & Technology

    2014-05-01

    of failed boards. This report presents the results of computerised tomography on multilayered Printed Circuit Boards using a SkyScan 1076 ...including any internal layers of a PCB. In this report we describe examples of the use of a SkyScan 1076 X-ray CT system as a non-destructive...problematic when scanning larger PCBs. Although the maximum PCB size for the SkyScan 1076 was 65 mm x 400 mm the range of samples used allowed a

  4. Laser cleaning of printed circuit boards

    NASA Astrophysics Data System (ADS)

    Song, W. D.; Hong, M. H.; Lu, Y. F.; Chong, T. C.

    2003-03-01

    Laser cleaning of printed circuit boards (PCB) has been studied in this paper. It is demonstrated that laser cleaning is a powerful tool to remove resin contaminants from printed circuit boards. A Nd:YAG laser is used as a light source for laser cleaning. The beam profile of the YAG laser is reshaped and homogenized into a square beam with uniform energy distribution in the focal plane of the focusing lens by using an optical system. The printed circuit board surfaces before and after laser cleaning were inspected by an optical microscope, analysed by X-ray photoelectron spectroscopy and monitored by an acoustic wave detection method. The cleaning threshold is about 75 mJ/cm 2 and no damage is observed below 400 mJ/cm 2.

  5. Printed circuit board electrodes for transmural cardiac mapping.

    PubMed

    Dosdall, Derek J; Huang, Jian; Smith, William M; Allred, James D; Allison, J Scott; Ideker, Raymond E

    2006-01-01

    Plunge needle recording techniques have provided valuable insights into transmural activation in cardiac tissue. Construction of plunge needles has been a costly and time intensive endeavor. Plunge needles constructed with standard printed circuit board (PCB) technology and methods are outlined. PCB plunge needles are less expensive in terms of raw materials and time required for construction than hypodermic stock or epoxy plunge needles. Tested PCB plunge needles recorded signals comparable to signals recorded by other plunge needles. PCB plunge needles provide an economical and rapid alternative to previously published techniques for plunge needle design.

  6. Coating Circuit Boards With Silicone

    NASA Technical Reports Server (NTRS)

    Gaudiano, S.

    1986-01-01

    Techniques appropriate to boards containing CMOS circuits detailed. Document presents procedure for applying thin conformal coating to such electronic assemblies as printed-circuit boards and wire-wrapped boards. Coating is from 1 to 7 mils (25 to 178 micrometers) thick and composed of room-temperature-vulcanizing (RTV) silicone. Specifies materials, equipment, spraying method, and quality requirements. Takes into account special needs of circuits made with complementary metal-oxide/semiconductor (CMOS) devices on circuit boards. Special attention given to preventing damage by electrostatic discharge, to which CMOS circuits especially sensitive.

  7. Electrically Tuneable EBG Integrated Circuits

    DTIC Science & Technology

    2013-12-01

    fabrication processes leveraging a technique previously developed for Printed Circuit Board (PCB). 15. SUBJECT TERMS Metamaterials, Radio...an integrated circuit (IC) fabrication processes leveraging a technique previously developed for Printed Circuit Board (PCB). Early design work...induces the EBG and as such is not tuneable [1] if implemented as integrated circuits (IC) or printed circuit boards (PCB). Previous work by this

  8. Sliding contacts on printed circuit boards and wear behavior

    NASA Astrophysics Data System (ADS)

    Le Solleu, J.-P.

    2010-04-01

    Automotive suppliers use since decades printed circuit boards (PCB) gold plating pads, as direct contact interface for low current sliding contacts. Several gold plating processes are available on the market, providing various wear behaviour. Some specific galvanic hard gold (AuCo or AuNi). plating was developed on PCB's. This specific plating generates extra costs due to the material quantity and also the process complexity. In a cost driven industry, the challenge is to use a standard low cost PCB for systems requesting high reliability performances. After a brief overview of standard PCB manufacturing processes and especially gold plating processes, the global experimental results of wear behaviour of three different gold plating technologies will be exposed and an explanation of the correlation between surface key parameters and wear out will be provided.

  9. Prototype and Short-Run Printed Circuit Board Creation

    DTIC Science & Technology

    1993-03-01

    be immersed in a nonmetallic tray of tin- plate solution to provide a protective coating to the copper. The tinning solution should be agitated by...rocking the tray , and the coating process monitored by observation. After sufficient tin- plate has been deposited, the PCB is removed, cleaned, dried...TECHNICAL REPORT RD[-WS-92-13 DTIC ILa-;; ELECTE APR 22 1993 PROTOTYPE AND SHORT-RUN STu C -PRINTED CIRCUIT BOARD CREATION Darryl H6lder Weapons

  10. Printed Circuit Board Quality Assurance

    NASA Technical Reports Server (NTRS)

    Sood, Bhanu

    2016-01-01

    PCB Assurance Summary: PCB assurance actives are informed by risk in context of the Project. Lessons are being applied across Projects for continuous improvements. Newer component technologies, smaller/high pitch devices: tighter and more demanding PCB designs: Identifying new research areas. New materials, designs, structures and test methods.

  11. Recycling of WEEE: Characterization of spent printed circuit boards from mobile phones and computers

    SciTech Connect

    Yamane, Luciana Harue; Tavares de Moraes, Viviane; Crocce Romano Espinosa, Denise; Soares Tenorio, Jorge Alberto

    2011-12-15

    Highlights: > This paper presents new and important data on characterization of wastes of electric and electronic equipments. > Copper concentration is increasing in mobile phones and remaining constant in personal computers. > Printed circuit boards from mobile phones and computers would not be mixed prior treatment. - Abstract: This paper presents a comparison between printed circuit boards from computers and mobile phones. Since printed circuits boards are becoming more complex and smaller, the amount of materials is constantly changing. The main objective of this work was to characterize spent printed circuit boards from computers and mobile phones applying mineral processing technique to separate the metal, ceramic, and polymer fractions. The processing was performed by comminution in a hammer mill, followed by particle size analysis, and by magnetic and electrostatic separation. Aqua regia leaching, loss-on-ignition and chemical analysis (inductively coupled plasma atomic emission spectroscopy - ICP-OES) were carried out to determine the composition of printed circuit boards and the metal rich fraction. The composition of the studied mobile phones printed circuit boards (PCB-MP) was 63 wt.% metals; 24 wt.% ceramics and 13 wt.% polymers; and of the printed circuit boards from studied personal computers (PCB-PC) was 45 wt.% metals; 27 wt.% polymers and ceramics 28 wt.% ceramics. The chemical analysis showed that copper concentration in printed circuit boards from personal computers was 20 wt.% and in printed circuit boards from mobile phones was 34.5 wt.%. According to the characteristics of each type of printed circuit board, the recovery of precious metals may be the main goal of the recycling process of printed circuit boards from personal computers and the recovery of copper should be the main goal of the recycling process of printed circuit boards from mobile phones. Hence, these printed circuit boards would not be mixed prior treatment. The results of

  12. Packaging printed circuit boards: A production application of interactive graphics

    NASA Technical Reports Server (NTRS)

    Perrill, W. A.

    1975-01-01

    The structure and use of an Interactive Graphics Packaging Program (IGPP), conceived to apply computer graphics to the design of packaging electronic circuits onto printed circuit boards (PCB), were described. The intent was to combine the data storage and manipulative power of the computer with the imaginative, intuitive power of a human designer. The hardware includes a CDC 6400 computer and two CDC 777 terminals with CRT screens, light pens, and keyboards. The program is written in FORTRAN 4 extended with the exception of a few functions coded in COMPASS (assembly language). The IGPP performs four major functions for the designer: (1) data input and display, (2) component placement (automatic or manual), (3) conductor path routing (automatic or manual), and (4) data output. The most complex PCB packaged to date measured 16.5 cm by 19 cm and contained 380 components, two layers of ground planes and four layers of conductors mixed with ground planes.

  13. Circuit Boards on Rover 2

    NASA Technical Reports Server (NTRS)

    2003-01-01

    April 15, 2003Prelaunch at Kennedy Space Center

    In the Payload Hazardous Servicing Facility, technicians remove one of the circuit boards on the Mars Exploration Rover 2 (MER-2). To gain access to the spacecraft, its lander petals were reopened and its solar panels deployed. A concern arose during prelaunch testing regarding how the spacecraft interprets signals sent from its main computer to peripherals in the cruise stage, lander and small deep space transponder. The MER Mission consists of two identical rovers set to launch in June 2003. The problem will be fixed on both rovers.

  14. Recycling of WEEE: characterization of spent printed circuit boards from mobile phones and computers.

    PubMed

    Yamane, Luciana Harue; de Moraes, Viviane Tavares; Espinosa, Denise Crocce Romano; Tenório, Jorge Alberto Soares

    2011-12-01

    This paper presents a comparison between printed circuit boards from computers and mobile phones. Since printed circuits boards are becoming more complex and smaller, the amount of materials is constantly changing. The main objective of this work was to characterize spent printed circuit boards from computers and mobile phones applying mineral processing technique to separate the metal, ceramic, and polymer fractions. The processing was performed by comminution in a hammer mill, followed by particle size analysis, and by magnetic and electrostatic separation. Aqua regia leaching, loss-on-ignition and chemical analysis (inductively coupled plasma atomic emission spectroscopy - ICP-OES) were carried out to determine the composition of printed circuit boards and the metal rich fraction. The composition of the studied mobile phones printed circuit boards (PCB-MP) was 63 wt.% metals; 24 wt.% ceramics and 13 wt.% polymers; and of the printed circuit boards from studied personal computers (PCB-PC) was 45 wt.% metals; 27 wt.% polymers and ceramics 28 wt.% ceramics. The chemical analysis showed that copper concentration in printed circuit boards from personal computers was 20 wt.% and in printed circuit boards from mobile phones was 34.5 wt.%. According to the characteristics of each type of printed circuit board, the recovery of precious metals may be the main goal of the recycling process of printed circuit boards from personal computers and the recovery of copper should be the main goal of the recycling process of printed circuit boards from mobile phones. Hence, these printed circuit boards would not be mixed prior treatment. The results of this paper show that copper concentration is increasing in mobile phones and remaining constant in personal computers.

  15. Design of a 75-140 GHz high-pass printed circuit board dichroic filter

    NASA Astrophysics Data System (ADS)

    Kim, Dong Hwi; Mohyuddin, Wahab; Woo, Dong Sik; Choi, Hyun Chul; Kim, Kang Wook

    2017-03-01

    A new high-performing PCB (Printed Circuit Board) dichroic filter, which can be used for the KSTAR (Korea Superconducting Tokamak Advanced Research) electron cyclotron emission imaging system, is proposed. The current dichroic filter consists of a triangular lattice array of circular holes on the 6-mm thick metal plate, while circular hole spacing limitation caused relatively narrow passband (˜20 GHz). On the other hand, the proposed PCB dichroic filter utilizes the inexpensive commercial PCB fabrication process with a flexible adjustment of circular hole spacing. Therefore, the proposed PCB dichroic filter provides significantly wider passband (˜60 GHz with 0.84 dB insertion loss) with much reduced weight and expense. Also, it is shown that a steep skirt property can be obtained with the thick PCB filter substrate. The design process, fabrication, and measurement results of the new PCB dichroic filter are described.

  16. Design of a 75-140 GHz high-pass printed circuit board dichroic filter.

    PubMed

    Kim, Dong Hwi; Mohyuddin, Wahab; Woo, Dong Sik; Choi, Hyun Chul; Kim, Kang Wook

    2017-03-01

    A new high-performing PCB (Printed Circuit Board) dichroic filter, which can be used for the KSTAR (Korea Superconducting Tokamak Advanced Research) electron cyclotron emission imaging system, is proposed. The current dichroic filter consists of a triangular lattice array of circular holes on the 6-mm thick metal plate, while circular hole spacing limitation caused relatively narrow passband (∼20 GHz). On the other hand, the proposed PCB dichroic filter utilizes the inexpensive commercial PCB fabrication process with a flexible adjustment of circular hole spacing. Therefore, the proposed PCB dichroic filter provides significantly wider passband (∼60 GHz with 0.84 dB insertion loss) with much reduced weight and expense. Also, it is shown that a steep skirt property can be obtained with the thick PCB filter substrate. The design process, fabrication, and measurement results of the new PCB dichroic filter are described.

  17. Design principles and realization of electro-optical circuit boards

    NASA Astrophysics Data System (ADS)

    Betschon, Felix; Lamprecht, Tobias; Halter, Markus; Beyer, Stefan; Peterson, Harry

    2013-02-01

    The manufacturing of electro-optical circuit boards (EOCB) is based to a large extent on established technologies. First products with embedded polymer waveguides are currently produced in series. The range of applications within the sensor and data communication markets is growing with the increasing maturity level. EOCBs require design flows, processes and techniques similar to existing printed circuit board (PCB) manufacturing and appropriate for optical signal transmission. A key aspect is the precise and automated assembly of active and passive optical components to the optical waveguides which has to be supported by the technology. The design flow is described after a short introduction into the build-up of EOCBs and the motivation for the usage of this technology within the different application fields. Basis for the design of EOCBs are the required optical signal transmission properties. Thereafter, the devices for the electro-optical conversion are chosen and the optical coupling approach is defined. Then, the planar optical elements (waveguides, splitters, couplers) are designed and simulated. This phase already requires co-design of the optical and electrical domain using novel design flows. The actual integration of an optical system into a PCB is shown in the last part. The optical layer is thereby laminated to the purely electrical PCB using a conventional PCB-lamination process to form the EOCB. The precise alignment of the various electrical and optical layers is thereby essential. Electrical vias are then generated, penetrating also the optical layer, to connect the individual electrical layers. Finally, the board has to be tested electrically and optically.

  18. Printed circuit board metal powder filters for low electron temperatures.

    PubMed

    Mueller, Filipp; Schouten, Raymond N; Brauns, Matthias; Gang, Tian; Lim, Wee Han; Lai, Nai Shyan; Dzurak, Andrew S; van der Wiel, Wilfred G; Zwanenburg, Floris A

    2013-04-01

    We report the characterisation of printed circuit boards (PCB) metal powder filters and their influence on the effective electron temperature which is as low as 22 mK for a quantum dot in a silicon MOSFET structure in a dilution refrigerator. We investigate the attenuation behaviour (10 MHz-20 GHz) of filter made of four metal powders with a grain size below 50 μm. The room-temperature attenuation of a stainless steel powder filter is more than 80 dB at frequencies above 1.5 GHz. In all metal powder filters, the attenuation increases with temperature. Compared to classical powder filters, the design presented here is much less laborious to fabricate and specifically the copper powder PCB-filters deliver an equal or even better performance than their classical counterparts.

  19. Removing Bonded Integrated Circuits From Boards

    NASA Technical Reports Server (NTRS)

    Rice, John T.

    1989-01-01

    Small resistance heater makes it easier, faster, and cheaper to remove integrated circuit from hybrid-circuit board, package, or other substrate for rework. Heater, located directly in polymeric bond interface or on substrate under integrated-circuit chip, energized when necessary to remove chip. Heat generated softens adhesive or solder that bonds chip to substrate. Chip then lifted easily from substrate.

  20. Reducing Printed Circuit Board Emissions with Low-Noise Design Practices

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur T.; Fowler, Jennifer; Yavoich, Brian J.; Jennings, Stephen A.

    2012-01-01

    This paper presents the results of an experiment designed to determine the effectiveness of adopting several low-noise printed circuit board (PCB) design practices. Two boards were designed and fabricated, each consisting of identical mixed signal circuitry. Several important differences were introduced between the board layouts: one board was constructed using recommended low-noise practices and the other constructed without such attention. The emissions from the two boards were then measured and compared, demonstrating an improvement in radiated emissions of up to 22 dB.

  1. Ultrasonic evaluation of high voltage circuit boards

    NASA Technical Reports Server (NTRS)

    Klima, S. J.; Riley, T. J.

    1976-01-01

    Preliminary observations indicate that an ultrasonic scanning technique may be useful as a quick, low cost, nondestructive method for judging the quality of circuit board materials for high voltage applications. Corona inception voltage tests were conducted on fiberglass-epoxy and fiberglass-polyimide high pressure laminates from 20 to 140 C. The same materials were scanned ultrasonically by utilizing the single transducer, through-transmission technique with reflector plate, and recording variations in ultrasonic energy transmitted through the board thickness. A direct relationship was observed between ultrasonic transmission level and corona inception voltage. The ultrasonic technique was subsequently used to aid selection of high quality circuit boards for the Communications Technology Satellite.

  2. Life cycle assessment of a printed circuit board manufacturing plant in Turkey.

    PubMed

    Ozkan, Elif; Elginoz, Nilay; Germirli Babuna, Fatos

    2017-09-29

    The objective of this study is to investigate the environmental impacts of a printed circuit board (PCB) manufacturing plant through streamlined life cycle assessment approach. As a result, the most effective recommendations on minimizing the environmental impacts for the mentioned sector are revealed and first steps towards establishing a country specific database are taken. The whole PCB production consists of two consecutive stages: namely board fabrication followed by the manufacturing of PCB. Manufacturing of PCB contributes the highest shares to freshwater aquatic ecotoxicity potential (FAETP) and ozone layer depletion potential (ODP). Eighty-nine percent of FAETP is found to be generated from the manufacturing of PCB. Almost all of this contribution can be attributed to the disposal of copper containing wastewater treatment sludge from etching operations to incineration. On the other hand, PCB manufacturing has 73% share in total ODP. Within the manufacturing of PCB, as etching operations are found to be of importance for all the impact categories except eutrophication potential (EP), it is recommended to focus further studies on in-plant control of etching.

  3. Printed circuit board layout by microcomputer

    NASA Astrophysics Data System (ADS)

    Krausman, E. W.

    1983-12-01

    Printed circuit board artwork is usually prepared manually because of the unavailability of computer-aided-design tools. This thesis presents the design of a microcomputer based printed circuit board layout system that is easy to use and cheap. Automatic routing and component placement routines will significantly speed up the process. The design satisfies the following requirements: Microcomputer implementation, portable, algorithm independent, interactive, and user friendly. When it is fully implemented a user will be able to select components and a board outline from an automated catalog, enter a schematic diagram, position the components on the board, and completely route the board from a single graphics terminal. Currently, the user interface and the outer level command processor have been implemented in Pascal. Future versions will be written in C for better portability.

  4. Device serves as hinge and electrical connector for circuit boards

    NASA Technical Reports Server (NTRS)

    Bethel, P. G.; Harris, G. G.

    1966-01-01

    Hinge makes both sides of electrical circuit boards readily accessible for component checkout and servicing. The hinge permits mounting of two circuit boards and incorporates connectors to maintain continuous electrical contact between the components on both boards.

  5. Vibration suppression of printed circuit boards using an external particle damper

    NASA Astrophysics Data System (ADS)

    Veeramuthuvel, P.; Sairajan, K. K.; Shankar, K.

    2016-03-01

    Particle damping is an effective method of passive vibration control, of recent research interest. The novel use of particle damper capsule on a Printed Circuit Board (PCB) and the development of Radial Basis Function neural network to accurately predict the acceleration response is presented here. The prediction of particle damping using this neural network is studied in comparison with the Back Propagation Neural network. Extensive experiments are carried out on a PCB for different combinations of particle damper parameters such as particle size, particle density, packing ratio, and the input force during the primary modes of vibration and the obtained results are used for training and testing of neural networks. Based on the prediction from the better trained network, useful design guidelines for the particle damper suitable for PCB are arrived at. The effectiveness of particle dampers for vibration suppression of PCB under random vibration environment is demonstrated based on these design guidelines.

  6. Flexible composite film for printed circuit board

    NASA Technical Reports Server (NTRS)

    Yabe, K.; Asakura, M.; Tanaka, H.; Soda, A.

    1982-01-01

    A flexible printed circuit for a printed circuit board in which layers of reaction product composed of a combination of phenoxy resin - polyisocyanate - brominated epoxy resin, and in which the equivalent ratio of those functional groups is hydroxyl group: isocyanate group: epoxy group - 1 : 0.2 to 2 : 0.5 to 3 are laminated on at least one side of saturated polyester film is discussed.

  7. Detection of Banned and Restricted Ozone-Depleting Chemicals in Printed Circuit Boards

    SciTech Connect

    Lee, Richard N.; Wright, Bob W.

    2008-12-01

    A study directed toward the detection of halogenated solvents in the matrix of circuit boards has recently been completed. This work was undertaken to demonstrate the potential for reliable detection of solvents used during the fabrication of printed circuit boards (PCB). Since many of these solvents are now, or soon will be, restricted under the terms of legislation enacted in response to the Montreal Protocol and other international agreements, the work described here, conducted over a period of more that 4 years, has provided guidance for the development of chromatographic system and analytical protocol to assure compliance with regulations introduced to control, or ban, industrial solvents associated with adverse environmental impact.

  8. Converting non-metallic printed circuit boards waste into a value added product

    PubMed Central

    2013-01-01

    The aim of this study was to investigate the feasibility of using nonmetallic printed circuit board (PCB) waste as filler in recycled HDPE (rHDPE) in production of rHDPE/PCB composites. Maleic anhydride modified linear low-density polyethylene (MAPE) was used as compatibilizer. In particular, the effects of nonmetallic PCB and MAPE on mechanical properties of the composites were assessed through tensile, flexural and impact testing. Scanning electron microscope (SEM) was used to study the dispersion of nonmetallic PCB and MAPE in the matrix. Nonmetallic PCB was blended with rHDPE from 0–30 wt% and prepared by counter-rotating twin screw extruder followed by molding into test samples via hot press for analysis. A good balance between stiffness, strength and toughness was achieved for the system containing 30 wt% PCB. Thus, this system was chosen in order to investigate the effect of the compatibilizer on the mechanical properties of the composites. The results indicate that MAPE as a compatiblizer can effectively promote the interfacial adhesion between nonmetallic PCB and rHDPE. The addition of 6 phr MAPE increased the flexural strength, tensile strength and impact strength by 71%, 98% and 44% respectively compared to the uncompatibilized composites. PMID:24764542

  9. Converting non-metallic printed circuit boards waste into a value added product.

    PubMed

    Muniyandi, Shantha Kumari; Sohaili, Johan; Hassan, Azman; Mohamad, Siti Suhaila

    2013-01-01

    The aim of this study was to investigate the feasibility of using nonmetallic printed circuit board (PCB) waste as filler in recycled HDPE (rHDPE) in production of rHDPE/PCB composites. Maleic anhydride modified linear low-density polyethylene (MAPE) was used as compatibilizer. In particular, the effects of nonmetallic PCB and MAPE on mechanical properties of the composites were assessed through tensile, flexural and impact testing. Scanning electron microscope (SEM) was used to study the dispersion of nonmetallic PCB and MAPE in the matrix. Nonmetallic PCB was blended with rHDPE from 0-30 wt% and prepared by counter-rotating twin screw extruder followed by molding into test samples via hot press for analysis. A good balance between stiffness, strength and toughness was achieved for the system containing 30 wt% PCB. Thus, this system was chosen in order to investigate the effect of the compatibilizer on the mechanical properties of the composites. The results indicate that MAPE as a compatiblizer can effectively promote the interfacial adhesion between nonmetallic PCB and rHDPE. The addition of 6 phr MAPE increased the flexural strength, tensile strength and impact strength by 71%, 98% and 44% respectively compared to the uncompatibilized composites.

  10. The p53 circuit board

    PubMed Central

    Sullivan, Kelly D.; Gallant-Behm, Corrie L.; Henry, Ryan E.; Fraikin, Jean-Luc; Espinosa, Joaquín M.

    2012-01-01

    The p53 tumor suppressor is embedded in a large gene network controlling diverse cellular and organismal phenotypes. Multiple signaling pathways converge onto p53 activation, mostly by relieving the inhibitory effects of its repressors, MDM2 and MDM4. In turn, signals originating from increased p53 activity diverge into distinct effector pathways to deliver a specific cellular response to the activating stimuli. Much attention has been devoted to dissecting how the various input pathways trigger p53 activation and how the activity of the p53 protein itself can be modulated by a plethora of co-factors and post-translational modifications. In this review we will focus instead on the multiple configurations of the effector pathways. We will discuss how p53-generated signals are transmitted, amplified, resisted and eventually integrated by downstream gene circuits operating at the transcriptional, post-transcriptional and post-translational level. We will also discuss how context-dependent variations in these gene circuits define the cellular response to p53 activation and how they may impact the clinical efficacy of p53-based targeted therapies. PMID:22333261

  11. Chemical inertness of UV-cured optical elastomers within the printed circuit board manufacturing process for embedded waveguide applications

    NASA Astrophysics Data System (ADS)

    Kruse, Kevin; Walczak, Karl; Thomas, Nicholas; Swatowski, Brandon; Demars, Casey; Middlebrook, Christopher

    2014-03-01

    Embedding polymer optical waveguides (WGs) into printed circuit boards (PCBs) for intra-board or board-to-board high speed data communications requires polymer materials that are compatible and inert when exposed to common PCB manufacturing processes. Ensuring both WG functionality after chemical exposure and maintaining PCB manufacturing integrities within the production process is crucial for successful implementation. The PCB manufacturing flow is analyzed to expose major requirements that would be required for the successful implementation of polymer materials for embedded WG development. Chemical testing and analysis were performed on Dow Corning ® OE-4140 UV-Cured Optical Elastomer Core and Dow Corning® OE-4141 UV-Cured Optical Elastomer Cladding which are designed for low loss embedded optical WGs. Contamination testing was conducted to demonstrate polymer compatibility in both cured and uncured form. Various PCB chemicals were treated with uncured polymer material and tested for effective contamination. Fully polymerized multimode WGs were fabricated and exposed to PCB chemicals at temperatures and durations comparable to PCB manufacturing conditions. Chemical analysis shows that the chosen polymer is compatible and inert with most common PCB manufacturing processes.

  12. Effect of Heat-Treatment on Metallic Collection for Used Printed Circuit Board

    NASA Astrophysics Data System (ADS)

    Agawa, Ryuichi; Tsugita, Yasuhiro; Nishida, Minoru; Araki, Takao

    In this research, we examined the method that separates the material from the printed circuit board by the proof scale heat-treatment. The size of the printed circuit board (PCB) used for the examination was about 150 mm × 200 mm, and PCB was executed heat-treatment by two kinds of shape as received (Sample-A) and crushed (Sample-B) by hammarcrasher. The following result was obtained. The organic resin and also omine were removed by the heat treatment in both cases. In Sample-B heat-treatment, though combustion was done with stability, however, the temperature rises locally so that the organism in the board crushed by the high contact with oxygen may burn instantaneously and the combustion residue melted solidifies. In Sample-A heat-treatment, the metallic collection rate in the combustion residue was higher than Sample-B, especially Cu and Ni are collected by 90mass% or more, and Ag, Au and Pb collected were twice larger compared with Sample-B. The residue in Sample-A could be crushed comparatively easily with hammarcrasher. Therefore, to make the crushing combustion residue concentrated of the metal in the printed circuit board adjust to metallic refinement process, it is thought that we should heat-treat the printed circuit board near as received.

  13. Metals Recovery from Artificial Ore in Case of Printed Circuit Boards, Using Plasmatron Plasma Reactor

    PubMed Central

    Szałatkiewicz, Jakub

    2016-01-01

    This paper presents the investigation of metals production form artificial ore, which consists of printed circuit board (PCB) waste, processed in plasmatron plasma reactor. A test setup was designed and built that enabled research of plasma processing of PCB waste of more than 700 kg/day scale. The designed plasma process is presented and discussed. The process in tests consumed 2 kWh/kg of processed waste. Investigation of the process products is presented with their elemental analyses of metals and slag. The average recovery of metals in presented experiments is 76%. Metals recovered include: Ag, Au, Pd, Cu, Sn, Pb, and others. The chosen process parameters are presented: energy consumption, throughput, process temperatures, and air consumption. Presented technology allows processing of variable and hard-to-process printed circuit board waste that can reach up to 100% of the input mass. PMID:28773804

  14. Metals Recovery from Artificial Ore in Case of Printed Circuit Boards, Using Plasmatron Plasma Reactor.

    PubMed

    Szałatkiewicz, Jakub

    2016-08-10

    This paper presents the investigation of metals production form artificial ore, which consists of printed circuit board (PCB) waste, processed in plasmatron plasma reactor. A test setup was designed and built that enabled research of plasma processing of PCB waste of more than 700 kg/day scale. The designed plasma process is presented and discussed. The process in tests consumed 2 kWh/kg of processed waste. Investigation of the process products is presented with their elemental analyses of metals and slag. The average recovery of metals in presented experiments is 76%. Metals recovered include: Ag, Au, Pd, Cu, Sn, Pb, and others. The chosen process parameters are presented: energy consumption, throughput, process temperatures, and air consumption. Presented technology allows processing of variable and hard-to-process printed circuit board waste that can reach up to 100% of the input mass.

  15. Physically separating printed circuit boards with a resilient, conductive contact

    NASA Technical Reports Server (NTRS)

    Baker, John D. (Inventor); Montalvo, Alberto (Inventor)

    1999-01-01

    A multi-board module provides high density electronic packaging in which multiple printed circuit boards are stacked. Electrical power, or signals, are conducted between the boards through a resilient contact. One end of the contact is located at a via in the lower circuit board and soldered to a pad near the via. The top surface of the contact rests against a via of the facing printed circuit board.

  16. Improving Heat Transfer Performance of Printed Circuit Boards

    NASA Technical Reports Server (NTRS)

    Schatzel, Donald V.

    2009-01-01

    This paper will explore the ability of printed circuit boards laminated with a Carbon Core Laminate to transfer heat vs. standard printed circuit boards that use only thick layers of copper. The paper will compare the differences in heat transfer performance of printed circuit boards with and without CCL.

  17. Improving Heat Transfer Performance of Printed Circuit Boards

    NASA Technical Reports Server (NTRS)

    Schatzel, Donald V.

    2009-01-01

    This paper will explore the ability of printed circuit boards laminated with a Carbon Core Laminate to transfer heat vs. standard printed circuit boards that use only thick layers of copper. The paper will compare the differences in heat transfer performance of printed circuit boards with and without CCL.

  18. A Docking Casette For Printed Circuit Boards

    DOEpatents

    Barringer, Dennis R.; Seminaro, Edward J.; Toffler, Harold M.

    2003-08-19

    A docking apparatus for printed circuit boards including a cassette housing, having a housing base, a housing cover and a housing wall, wherein the housing base and the housing wall are disposed relative to each other so as to define a housing cavity for containing a printed circuit board and wherein the housing wall includes a cable opening disposed so as to be communicated with the housing cavity, a linkage mechanism, wherein the linkage mechanism includes an engagement configuration and a disengagement configuration and wherein the linkage mechanism is disposed so as to be associated with the cassette housing and a housing bezel, wherein the housing bezel is disposed relative to the cassette housing so as to be associated with the cable opening.

  19. 29 CFR 1915.181 - Electrical circuits and distribution boards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Electrical circuits and distribution boards. 1915.181... Electrical Machinery § 1915.181 Electrical circuits and distribution boards. (a) The provisions of this... employee is permitted to work on an electrical circuit, except when the circuit must remain energized...

  20. 29 CFR 1915.181 - Electrical circuits and distribution boards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Electrical circuits and distribution boards. 1915.181... Electrical Machinery § 1915.181 Electrical circuits and distribution boards. (a) The provisions of this... employee is permitted to work on an electrical circuit, except when the circuit must remain energized...

  1. 29 CFR 1915.181 - Electrical circuits and distribution boards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Electrical circuits and distribution boards. 1915.181... Electrical Machinery § 1915.181 Electrical circuits and distribution boards. (a) The provisions of this... employee is permitted to work on an electrical circuit, except when the circuit must remain energized...

  2. 29 CFR 1915.181 - Electrical circuits and distribution boards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Electrical circuits and distribution boards. 1915.181... Electrical Machinery § 1915.181 Electrical circuits and distribution boards. (a) The provisions of this... employee is permitted to work on an electrical circuit, except when the circuit must remain energized...

  3. 29 CFR 1915.181 - Electrical circuits and distribution boards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Electrical circuits and distribution boards. 1915.181... Electrical Machinery § 1915.181 Electrical circuits and distribution boards. (a) The provisions of this... employee is permitted to work on an electrical circuit, except when the circuit must remain energized...

  4. Printed Circuit Board Design with HDL Designer

    NASA Technical Reports Server (NTRS)

    Winkert, Thomas K.; LaFourcade, Teresa

    2004-01-01

    Staying up to date with the latest CAD tools both from a cost and time perspective is difficult. Within a given organization there may be experts in Printed Circuit Board Design tools and experts in FPGA/VHDL tools. Wouldn't it be great to have someone familiar with HDL Designer be able to design PCBs without having to learn another tool? This paper describes a limited experiment to do this.

  5. Automated inspection in printed circuit board assembly (PCBA) manufacturing

    NASA Astrophysics Data System (ADS)

    Abraham, Francy K.

    1997-08-01

    Visual inspection has long been a necessary method of quality control in Printed Circuit Board Assemblies (PCBA) manufacturing. The characteristics of electronic assemblies have changed substantially over the last decade. Todays high lead count, fine pitch SMT components are becoming even more difficult for humans to inspect at the same time automated inspection systems have become reliable than manual inspection and are now accepted as valuable tools for producing high quality PCBA products. The basic requirements of an automated inspection system remain same in all PCBA manufacturing but the type of the automated system (off- line/on-line), where applied in the production flow, entire boards or only on a sample basis, inspection coverage (100% or partial) vary between different PCBA manufacturers. In PCBA manufacturing the emphasis is more in the electrical functionality of the PCBA than in it's appearance. It is nearly impossible to impose stringent specifications in the appearance of the components and other materials used in PCBA manufacturing. Due to the large number of component/PCB supplier and wide variations in materials and processes the challenge in successfully automating the inspection process is the variability in the appearance of components on PCBA. But in a high volume PCBA manufacturing where fewer board types are running in large volumes for long periods of time, the variability in component appearance can be controlled much better than a low volume PCBA manufacturing where more types are running in low volumes for short period of time. This paper discusses the development and implementation of a low cost flexible automated inspection system for PCBAs. The system can detect over ninety percent of visual defects on PCBAs. The key features of the system are quick and easy set-up, capability to inspect different types of board and quick change over between different boards and low cost.

  6. Hard and flexible optical printed circuit board

    NASA Astrophysics Data System (ADS)

    Lee, El-Hang; Lee, Hyun Sik; Lee, S. G.; O, B. H.; Park, S. G.; Kim, K. H.

    2007-02-01

    We report on the design and fabrication of hard and flexible optical printed circuit boards (O-PCBs). The objective is to realize generic and application-specific O-PCBs, either in hard form or flexible form, that are compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly, for low-cost and high-volume universal applications. The O-PCBs consist of 2-dimensional planar arrays of micro/nano-scale optical wires, circuits and devices that are interconnected and integrated to perform the functions of sensing, storing, transporting, processing, switching, routing and distributing optical signals on flat modular boards. For fabrication, the polymer and organic optical wires and waveguides are first fabricated on a board and are used to interconnect and integrate micro/nano-scale photonic devices. The micro/nano-optical functional devices include lasers, detectors, switches, sensors, directional couplers, multi-mode interference devices, ring-resonators, photonic crystal devices, plasmonic devices, and quantum devices. For flexible boards, the optical waveguide arrays are fabricated on flexible poly-ethylen terephthalate (PET) substrates by UV embossing. Electrical layer carrying VCSEL and PD array is laminated with the optical layer carrying waveguide arrays. Both hard and flexible electrical lines are replaced with high speed optical interconnection between chips over four waveguide channels up to 10Gbps on each. We discuss uses of hard or flexible O-PCBs for telecommunication systems, computer systems, transportation systems, space/avionic systems, and bio-sensor systems.

  7. High density printed electrical circuit board card connection system

    DOEpatents

    Baumbaugh, Alan E.

    1997-01-01

    A zero insertion/extraction force printed circuit board card connection system comprises a cam-operated locking mechanism disposed along an edge portion of the printed circuit board. The extrusions along the circuit board mate with an extrusion fixed to the card cage having a plurality of electrical connectors. The card connection system allows the connectors to be held away from the circuit board during insertion/extraction and provides a constant mating force once the circuit board is positioned. The card connection system provides a simple solution to the need for a greater number of electrical signal connections.

  8. High density printed electrical circuit board card connection system

    DOEpatents

    Baumbaugh, A.E.

    1997-05-06

    A zero insertion/extraction force printed circuit board card connection system comprises a cam-operated locking mechanism disposed along an edge portion of the printed circuit board. The extrusions along the circuit board mate with an extrusion fixed to the card cage having a plurality of electrical connectors. The card connection system allows the connectors to be held away from the circuit board during insertion/extraction and provides a constant mating force once the circuit board is positioned. The card connection system provides a simple solution to the need for a greater number of electrical signal connections. 12 figs.

  9. Sequential computer algorithms for printed circuit board inspection

    NASA Astrophysics Data System (ADS)

    Hernandez, Moises E.; Villalobos, Jesus R.; Johnson, W. Carrol

    1993-08-01

    Surface mounted technology (SMT) in automated assembly facilities requires the use of automatic surface-mount-device (SMD) placement machines. One of the problems involved in the electronic printed circuit board (PCB) assembly process is the verification of the SMD placement operation within tight tolerances. The high throughput of modern manufacturing lines along with the required accuracy demand the use of automatic inspection systems to verify SMD placement. Image complexity of the board makes the use of machine vision for the inspection process a difficult task. This is complicated by the fact that misclassification errors should be kept to a minimum. Additionally, it is desirable that the inspection results provide enough information to be used for statistical process control (SPC). The strategy adopted to solve this problem was to simplify the complexity of the image by means of special illumination devices. The simplified image was then suitable for analysis by simple processing, segmentation, and detection algorithms that, sequentially applied to the image, met the required repeatability and accuracy specifications for the inspection system. The scope of this paper is to describe the techniques explored by the authors to solve the SMD inspection problem in order to develop a working industrial SMD inspection system.

  10. Chemical and biological processes for multi-metal extraction from waste printed circuit boards of computers and mobile phones.

    PubMed

    Shah, Monal B; Tipre, Devayani R; Dave, Shailesh R

    2014-11-01

    E-waste printed circuit boards (PCB) of computers, mobile-phones, televisions, LX (LongXiang) PCB in LED lights and bulbs, and tube-lights were crushed to ≥250 µm particle size and 16 different metals were analysed. A comparative study has been carried out to evaluate the extraction of Cu-Zn-Ni from computer printed circuit boards (c-PCB) and mobile-phone printed circuit boards (m-PCB) by chemical and biological methods. Chemical process showed the extraction of Cu-Zn-Ni by ferric sulphate was best among the studied chemical lixiviants. Bioleaching experiments were carried out with the iron oxidising consortium, which showed that when E-waste and inoculum were added simultaneously in the medium (one-step process); 60.33% and 87.50% Cu, 75.67% and 85.67% Zn and 71.09% and 81.87% Ni were extracted from 10 g L(-1) of c-PCB and m-PCB, respectively, within 10-15 days of reaction time. Whereas, E-waste added after the complete oxidation of Fe(2+) to Fe(3+) iron containing medium (two-step process) showed 85.26% and 99.99% Cu, 96.75% and 99.49% Zn and 93.23% and 84.21% Ni extraction from c-PCB and m-PCB, respectively, only in 6-8 days. Influence of varying biogenerated Fe(3+) and c-PCB concentrations showed that 16.5 g L(-1) of Fe(3+) iron was optimum up to 100 g L(-1) of c-PCB. Changes in pH, acid consumed and redox potential during the process were also studied. The present study shows the ability of an eco-friendly process for the recovery of multi-metals from E-waste even at 100 g L(-1) printed circuit boards concentration. © The Author(s) 2014.

  11. Developing 300°C Ceramic Circuit Boards

    SciTech Connect

    Normann, Randy A

    2015-02-15

    This paper covers the development of a geothermal ceramic circuit board technology using 3D traces in a machinable ceramic. Test results showing the circuit board to be operational to at least 550°C. Discussion on producing this type of board is outlined along with areas needing improvement.

  12. Printed circuit boards as platform for disposable lab-on-a-chip applications

    NASA Astrophysics Data System (ADS)

    Leiterer, Christian; Urban, Matthias; Fritzsche, Wolfgang; Goldys, Ewa; Inglis, David

    2015-12-01

    An increasing demand in performance from electronic devices has resulted in continuous shrinking of electronic components. This shrinkage has demanded that the primary integration platform, the printed circuit board (PCB), follow this same trend. Today, PCB companies offer ~100 micron sized features (depth and width) which mean they are becoming suitable as physical platforms for Lab-on-a-Chip (LOC) and microfluidic applications. Compared to current lithographic based fluidic approaches; PCB technology offers several advantages that are useful for this technology. These include: Being easily designed and changed using free software, robust structures that can often be reused, chip layouts that can be ordered from commercial PCB suppliers at very low cost (1 AUD each in this work), and integration of electrodes at no additional cost. Here we present the application of PCB technology in connection with microfluidics for several biomedical applications. In case of commercialization the costs for each device can be even further decreased to approximately one tenth of its current cost.

  13. Metal solubilization from powdered printed circuit boards by microbial consortium from bauxite and pyrite ores.

    PubMed

    Adhapure, N N; Waghmare, S S; Hamde, V S; Deshmukh, A M

    2013-01-01

    With the current rapid developments in technology, there is an increasing accumulation of outdated electronic equipment. The primary reason for this increase is the low rate of recycling due to the complex nature of such waste. Bioleaching offers a promising solution for this problem. Study was conducted on the solubilization of heavy metals from electronic waste (e-waste). For this purpose, a microbial consortium from bauxite and pyrite ore samples was obtained using a simple "top down" approach. Essentially, printed circuit boards (PCB) were obtained and used as representative samples of e-waste. Various concentrations (1-5%) of PCB powder were subjected to bioleaching, and the effects on metal solubilization, changes in pH and concentration of ferrous iron produced were assessed. It was observed that a maximum of 96.93% Cu and 93.33% Zn was solubilized by microbial consortium from 10 g/l of PCB powder, whereas only 10.26% Ni was solubilized from 30 g/l of PCB powder. For lead, only 0.58% solubilization was achieved from 20 g/l of PCB powder. An analysis of the precipitate formed during bioleaching using scanning electron microscopy with energy dispersive x-ray analysis revealed the presence of Tin (59.96%), Cu (23.97%), Pb (9.30%) and Fe (5.92%).

  14. A new unique electrostatic imager for nondestructive evaluation of printed circuit boards

    NASA Astrophysics Data System (ADS)

    Zentai, George; Partain, Larry D.; Proano, Cesar; Yamaoka, Syuji

    2003-07-01

    A new method (patent pending) was developed at Varian Medical Systems and OHT Inc. for non-destructive evaluation of printed circuit boards (PCB"s). The electrostatic imager uses a TFT array, where each pixel has a small storage capacitor connected to it and a separate top electrode. An insulator layer covers these top electrodes. When we place a PCB on top of this insulator layer and activate a trace of the PCB by an electrical pulse, that trace induces charges in all of the underlying pixels. By reading out the image of the charges with electronics, similar to ones used for digital x-ray imaging, we can reconstruct the image of the electrical trace. Using the above technique we can test and detect defects in PCB"s such as shorted traces, broken traces, etc. This method is also applicable to test other electrical and electronic circuits and components with electrical pulses. The paper gives a detailed descripton of this new imaging technique illustrated by real applications.

  15. A Precision Vision-Aided Dispensing System for Circuit Boards,

    DTIC Science & Technology

    tool exchanging capabilities. This paper discusses the technical approach used to perform a precision adhesive dispensing operation while accommodating the various tolerances of the microwave circuit board.

  16. Sampling and Control Circuit Board for an Inertial Measurement Unit

    NASA Technical Reports Server (NTRS)

    Chelmins, David T (Inventor); Powis, Richard T., Jr. (Inventor); Sands, Obed (Inventor)

    2016-01-01

    A circuit board that serves as a control and sampling interface to an inertial measurement unit ("IMU") is provided. The circuit board is also configured to interface with a local oscillator and an external trigger pulse. The circuit board is further configured to receive the external trigger pulse from an external source that time aligns the local oscillator and initiates sampling of the inertial measurement device for data at precise time intervals based on pulses from the local oscillator. The sampled data may be synchronized by the circuit board with other sensors of a navigation system via the trigger pulse.

  17. Effect of Ground Layer Patterns with Slits on Conducted Noise Currents from Printed Circuit Board

    NASA Astrophysics Data System (ADS)

    Maeno, Tsuyoshi; Unou, Takanori; Ichikawa, Kouji; Fujiwara, Osamu

    Electromagnetic disturbances for vehicle-mounted radios can be caused by conducted noise currents that flows out from electronic equipment for vehicles to wire-harnesses. In this paper, for reducing the conducted noise currents from electronic equipment for vehicles, we made a simulation and experiment on how ground patterns affect the noise currents from three-layer printed circuit boards (PCBs) with slit-types and plane-type ground patterns. As a result, we could confirm that slits on a ground pattern allow conducted noise currents to flow out from PCBs to wire-harnesses. For the PCBs with plane-type ground and one of three slit-type patterns, on the other hand, both the simulation and examination showed that resonance phenomena occur at unexpected low-frequencies. A circuit analysis revealed that the above phenomena can be caused by the imbalance of a bridge circuit consisting of the trace circuits on the PCB.

  18. Preparing printed circuit boards for rapid turn-around time on a plotter

    SciTech Connect

    Hawtree, J.

    1998-01-01

    This document describes the use of the LPKF ProtoMat mill/drill unit circuit board Plotter, with the associated CAD/CAM software BoardMaster and CircuitCAM. At present its primarily use here at Fermilab`s Particle Physics Department is for rapid-turnover of prototype PCBs double-sided and single-sided copper clad printed circuit boards (PCBs). (The plotter is also capable of producing gravure films and engraving aluminum or plastic although we have not used it for this.) It has the capability of making traces 0.004 inch wide with 0.004 inch spacings which is appropriate for high density surface mount circuits as well as other through-mounted discrete and integrated components. One of the primary benefits of the plotter is the capability to produce double-sided drilled boards from CAD files in a few hours. However to achieve this rapid turn-around time, some care must be taken in preparing the files. This document describes how to optimize the process of PCB fabrication. With proper preparation, researchers can often have a completed circuit board in a day`s time instead of a week or two wait with usual procedures. It is assumed that the software and hardware are properly installed and that the machinist is acquainted with the Win95 operating system and the basics of the associated software. This paper does not describe its use with pen plotters, lasers or rubouts. The process of creating a PCB (printed circuit board) begins with the CAD (computer-aided design) software, usually PCAD or VeriBest. These files are then moved to CAM (computer-aided machining) where they are edited and converted to put them into the proper format for running on the ProtoMat plotter. The plotter then performs the actual machining of the board. This document concentrates on the LPKF programs CircuitCam BASIS and BoardMaster for the CAM software. These programs run on a Windows 95 platform to run an LPKF ProtoMat 93s plotter.

  19. 78 FR 23591 - Certain Prepregs, Laminates, and Finished Circuit Boards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-19

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Prepregs, Laminates, and Finished Circuit Boards AGENCY: U.S. International Trade... circuit boards that infringe certain claims of United States Patent Nos. 6,187,852 (``the `852 patent...

  20. Optical system facilitates inspection of printed circuit boards

    NASA Technical Reports Server (NTRS)

    Cridlin, M.; Oconnor, J.

    1968-01-01

    Optical comparator method determines the quality and registration of surface features of double-sided printed circuit boards. Color-coded superimposed images of both sides of a printed circuit board are presented to view, clearly showing details and registration of the circuitry.

  1. Polymer waveguide sensor with tin oxide thin film integrated onto optical-electrical printed circuit board

    NASA Astrophysics Data System (ADS)

    Lim, Jung Woon; Kim, Seon Hoon; Kim, Jong-Sup; Kim, Jeong Ho; Kim, Yune Hyoun; Lim, Ju Young; Im, Young-Eun; Park, Jong Bok; Hann, Swook

    2014-05-01

    In this study, we proposed and fabricated optical sensor module integrated onto optical-electrical printed circuit board (PCB) for gas detection based on polymer waveguide with tin oxide thin film. Their potential application as gas sensors are confirmed through computational simulation using the two dimensional finite-difference time-domain method (2DFDTD). Optical-electrical PCB was integrated into vertical cavity surface emitting laser (VCSEL), photodiode and polymeric sensing device was fabricated by the nano-imprint lithography technique. SnO2 thin film of 100nm thickness was placed on the surface of core layer exposed by removing the specific area of the upper cladding layer of 300 μm length and 50 μm width. The performance of the device was measured experimentally. Initial study on the sensor performance for carbon monoxide gas detection indicated good sensitivity.

  2. Recovery of metals from waste printed circuit boards by a mechanical method using a water medium.

    PubMed

    Duan, Chenlong; Wen, Xuefeng; Shi, Changsheng; Zhao, Yuemin; Wen, Baofeng; He, Yaqun

    2009-07-15

    Research on the recycling of waste printed circuit boards (PCB) is at the forefront of environmental pollution prevention and resource recycling. To effectively crush waste PCB and to solve the problem of secondary pollution from fugitive odors and dust created during the crushing process, a wet impacting crusher was employed to achieve comminution liberation of the PCB in a water medium. The function of water in the crushing process was analyzed. When using slippery hammerheads, a rotation speed of 1470 rpm, a water flow of 6m(3)/h and a sieve plate aperture of 2.2mm, 95.87% of the crushed product was sized less than 1mm. 94.30% of the metal was in this grade of product. Using smashed material graded -1mm for further research, a Falcon concentrator was used to recover the metal from the waste PCB. Engineering considerations were the liberation degree, the distribution ratio of the metal and a way to simplify the technology. The separation mechanism for fine particles of different densities in a Falcon concentrator was analyzed in detail and the separation process in the segregation and separation zones was deduced. Also, the magnitude of centrifugal acceleration, the back flow water pressure and the feed slurry concentration, any of which might affect separation results, were studied. A recovery model was established using Design-Expert software. Separating waste PCB, crushed to -1mm, with the Falcon separator gave a concentrated product graded 92.36% metal with a recovery of 97.05%. To do this the reverse water pressure was 0.05 MPa, the speed transducer frequency was set at 30 Hz and the feed density was 20 g/l. A flow diagram illustrating the new technique of wet impact crushing followed by separation with a Falcon concentrator is provided. The technique will prevent environmental pollution from waste PCB and allow the effective recovery of resources. Water was used as the medium throughout the whole process.

  3. Direct-referencing Two-dimensional-array Digital Microfluidics Using Multi-layer Printed Circuit Board

    PubMed Central

    Gong, Jian; Kim, Chang-Jin “CJ”

    2008-01-01

    Digital (i.e. droplet-based) microfluidics, by the electrowetting-on-dielectric (EWOD) mechanism, has shown great potential for a wide range of applications, such as lab-on-a-chip. While most reported EWOD chips use a series of electrode pads essentially in one-dimensional line pattern designed for specific tasks, the desired universal chips allowing user-reconfigurable paths would require the electrode pads in two-dimensional pattern. However, to electrically access the electrode pads independently, conductive lines need to be fabricated underneath the pads in multiple layers, raising a cost issue especially for disposable chip applications. In this article, we report the building of digital microfluidic plates based on a printed-circuit-board (PCB), in which multilayer electrical access lines were created inexpensively using mature PCB technology. However, due to its surface topography and roughness and resulting high resistance against droplet movement, as-fabricated PCB surfaces require unacceptably high (~500 V) voltages unless coated with or immersed in oil. Our goal is EWOD operations of aqueous droplets not only on oil-covered but also on dry surfaces. To meet varying levels of performances, three types of gradually complex post-PCB microfabrication processes are developed and evaluated. By introducing land-grid-array (LGA) sockets in the packaging, a scalable digital microfluidics system with reconfigurable and low-cost chip is also demonstrated. PMID:19234613

  4. Tetrabromobisphenol A contamination and emission in printed circuit board production and implications for human exposure.

    PubMed

    Zhou, Xiaoyu; Guo, Jie; Zhang, Wei; Zhou, Peng; Deng, Jingjing; Lin, Kuangfei

    2014-05-30

    The emission of and exposure to tetrabromobisphenol A (TBBPA) during the production of printed circuit boards (PCBs) were evaluated in this study. TBBPA was determined in production wastes (fine solid waste, rinsing water, effluent and sludge) and environmental samples (dust and PM10) from a typical PCB plant. The TBBPA concentrations of the solid and liquid wastes were on the order of 10(2)-10(4)ng/g and 10(1)-10(2)ng/L, respectively. The highest emission to the environment was exhibited by the fine solid waste (187-1220μg/kg-PCB), suggesting the need for strict control of its production and disposal. Regarding the environmental samples, the TBBPA contents of dust (125-9090ng/g) and PM10 (12.3-1640pg/m(3)) were higher than other values reported worldwide, indicating that PCB production was a non-negligible source of TBBPA for the occupational environment. TBBPA contamination mainly occurred in the form of sedimentary dust rather than suspended particulate matter. According to our estimation, worker exposures to TBBPA via dust ingestion, dust dermal absorption and PM10 inhalation varied widely by process, with the greatest exposures being 1930, 431 and 96.5pg/kg-bw/day, respectively. The exposure via dust represented most of the overall exposure via the above three pathways in PCB workshops.

  5. Encapsulation of nonmetallic fractions recovered from printed circuit boards waste with thermoplastic.

    PubMed

    Muniyandi, Shantha Kumari; Sohaili, Johan; Hassan, Azman

    2014-09-01

    The present work includes a process for encapsulation by combining substantially simultaneously dry nonmetallic printed circuit boards (PCBs) powder and recycled high-density polyethylene (rHDPE) in an extruder to form a homogenous matrix. The extruded materials were then molded into standard tensile, flexural, and impact properties testing specimens. Nonmetallic PCB mainly consists of large amount of glass fiber-reinforced epoxy resin materials. Incorporation of 50 wt% nonmetallic PCB in rHDPE matrix had increased the flexural strength and modulus by 35% and 130%, respectively. Tensile strength reported to be constant without much improvement. However, the Young's modulus has increased by 180%, with incorporation of 50 wt% nonmetallic PCB. The addition of 6 phr (parts per hundred) maleated polyethylene (MAPE) resulted in 2-fold increase in tensile and flexural strength. Regarding the leaching properties, Cu was identified as the metal that leached at the highest level from the raw nonmetallic PCB, at 59.09 mg/L. However, after the nonmetallic PCB was filled in rHDPE/PCB composites, the concentration of Cu was reduced far below the regulatory limit, to only 3 mg/L. Thermal properties of composites were studied, and it was found out that incorporation of nonmetallic PCB fillers in rHDPE resulted in low thermal conductivity, whereas mechanical strength of the composites showed maximum improvements at 220 degrees C. Overall, the encapsulation technique using nonmetallic PCB waste has formed a monolithic waste form that provides a barrier to the dispersion of wastes into the environment. Implications: Nonmetallic materials reclaimed from waste PCBs were used to analyze the chemical composition, and it was found that nonmetalllic PCBs mainly consist of glass fiber-reinforced epoxy resin materials. With such millions of glass fibers in nonmetallic PCBs, there are mass-excellent supporting bodies that enhance the mechanical properties of composites. In fact, utilization

  6. STABLCOR™: A high conductivity, low CTE printed circuit board

    NASA Astrophysics Data System (ADS)

    Davis, William E.

    2002-01-01

    The power dissipation levels and the size (footprint) of integrated circuit components that are being assembled to printed circuit boards is causing significant thermal problems that require higher thermal conductivity and close matching of coefficient of thermal expansion. This is especially true when using chip scale devices, chip on board assembly and flip chip on board assembly procedures. AMT has developed a unique printed circuit board that has a thermally conductive layer laminated into the board, which has a thermal conductivity of 225 w/m-k and a very low coefficient of thermal expansion. These properties result in a printed circuit board that is thermally conductive and which has a coefficient of thermal expansion that is closely matched to silicon die and ceramic packages. AMT has demonstrated the benefits of this printed circuit board by conducting thermal cycling tests and vibration tests of boards that were populated with surface mount parts and flip chip on board parts. The testing was conducted under SBIR contracts funded by NASA Glenn Research Center. .

  7. Designing an Electronics Data Package for Printed Circuit Boards (PCBs)

    DTIC Science & Technology

    2013-08-01

    package to help avoid errors and rework . II. PCB DATA PACKAGE REQUIREMENTS LIST The technical data package is comprised of documentation including an...Memory Card International Association)  IPC-6015 MCM-L (Multi-Chip Module – Laminated )  IPC-6016 HDI (High Density Interconnect)  IPC-6018...Interconnect ICT In Circuit Tester IPC Association Connecting Electronics Industries MCM-L Multi-Chip Module – Laminated MIL Military NEMA National

  8. Theoretic model and computer simulation of separating mixture metal particles from waste printed circuit board by electrostatic separator.

    PubMed

    Li, Jia; Xu, Zhenming; Zhou, Yaohe

    2008-05-30

    Traditionally, the mixture metals from waste printed circuit board (PCB) were sent to the smelt factory to refine pure copper. Some valuable metals (aluminum, zinc and tin) with low content in PCB were lost during smelt. A new method which used roll-type electrostatic separator (RES) to recovery low content metals in waste PCB was presented in this study. The theoretic model which was established from computing electric field and the analysis of forces on the particles was used to write a program by MATLAB language. The program was design to simulate the process of separating mixture metal particles. Electrical, material and mechanical factors were analyzed to optimize the operating parameters of separator. The experiment results of separating copper and aluminum particles by RES had a good agreement with computer simulation results. The model could be used to simulate separating other metal (tin, zinc, etc.) particles during the process of recycling waste PCBs by RES.

  9. 4. INTERIOR VIEW SHOWING CIRCUIT BOARD HOUSING AND SWITCHING EQUIPMENT; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. INTERIOR VIEW SHOWING CIRCUIT BOARD HOUSING AND SWITCHING EQUIPMENT; VIEW TO SOUTHEAST. - Cape Canaveral Air Station, Launch Complex 17, Facility 36003, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

  10. A new low-expansion nonflammable printed circuit board

    NASA Technical Reports Server (NTRS)

    Kennedy, B. W.

    1970-01-01

    Printed circuit board has a thermal coefficient of expansion similar to that of the electronic component leads. High-expansion composite materials are sandwiched between the outer layers of copper and woven fiber glass.

  11. Modular chassis simplifies packaging and interconnecting of circuit boards

    NASA Technical Reports Server (NTRS)

    Arens, W. E.; Boline, K. G.

    1964-01-01

    A system of modular chassis structures has simplified the design for mounting a number of printed circuit boards. This design is structurally adaptable to computer and industrial control system applications.

  12. Fate of bromine in pyrolysis of printed circuit board wastes.

    PubMed

    Chien, Y C; Wang, H P; Lin, K S; Huang, Y J; Yang, Y W

    2000-02-01

    Behavior of Br in pyrolysis of the printed circuit board waste with valuable copper and oil recycling has been studied in the present work. Experimentally, pyrolysis of the printed circuit board waste generated approximately 40.6% of oils, 24.9% of noncondensible gases and 34.5% of solid residues that enriched in copper (90-95%). The cuts of the oils produced from pyrolysis of the printed circuit board waste into weighted boiling fraction were primarily light naphtha and heavy gas oil. Approximately 72.3% of total Br in the printed circuit board waste were found in product gas mainly as HBr and bromobenzene. However, by extended X-ray absorption fine structural (EXAFS) spectroscopy, Cu-O and Cu-(O)-Cu species with bond distance of 1.87 and 2.95 A, respectively, were observed in the solid residues. Essentially, no Cu-Br species was found.

  13. Isolation of Battery Chargers Integrated Into Printed Circuit Boards

    SciTech Connect

    Sullivan, James S.

    2013-11-21

    Present test procedures developed by the Federal Government (10 CFR Part 430 “Energy Conservation Program for Consumer Products”) to measure the energy consumption of battery chargers provide no method for the isolation of input power for battery chargers that have been integrated into printed circuit boards internal to electronic equipment. This prevents the measurement of Standby and Off Mode energy consumption. As a result, the energy consumption of battery chargers integrated into the printed circuit board cannot be measured.

  14. Process produces accurate registry between circuit board prints

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Tapes and quick-mount circles of contrasting colors aid in obtaining precise registry between the two circuits of two-sided printed circuit boards. The tapes and circles are mounted on opposite sides of transparent plastic film to define the conductive path and feed-through hole locations.

  15. Electrochemical Migration Behavior of Copper-Clad Laminate and Electroless Nickel/Immersion Gold Printed Circuit Boards under Thin Electrolyte Layers.

    PubMed

    Yi, Pan; Xiao, Kui; Ding, Kangkang; Dong, Chaofang; Li, Xiaogang

    2017-02-08

    The electrochemical migration (ECM) behavior of copper-clad laminate (PCB-Cu) and electroless nickel/immersion gold printed circuit boards (PCB-ENIG) under thin electrolyte layers of different thicknesses containing 0.1 M Na₂SO₄ was studied. Results showed that, under the bias voltage of 12 V, the reverse migration of ions occurred. For PCB-Cu, both copper dendrites and sulfate precipitates were found on the surface of FR-4 (board material) between two plates. Moreover, the Cu dendrite was produced between the two plates and migrated toward cathode. Compared to PCB-Cu, PCB-ENIG exhibited a higher tendency of ECM failure and suffered from seriously short circuit failure under high relative humidity (RH) environment. SKP results demonstrated that surface potentials of the anode plates were greater than those of the cathode plates, and those potentials of the two plates exhibited a descending trend as the RH increased. At the end of the paper, an electrochemical migration corrosion failure model of PCB was proposed.

  16. Electrochemical Migration Behavior of Copper-Clad Laminate and Electroless Nickel/Immersion Gold Printed Circuit Boards under Thin Electrolyte Layers

    PubMed Central

    Yi, Pan; Xiao, Kui; Ding, Kangkang; Dong, Chaofang; Li, Xiaogang

    2017-01-01

    The electrochemical migration (ECM) behavior of copper-clad laminate (PCB-Cu) and electroless nickel/immersion gold printed circuit boards (PCB-ENIG) under thin electrolyte layers of different thicknesses containing 0.1 M Na2SO4 was studied. Results showed that, under the bias voltage of 12 V, the reverse migration of ions occurred. For PCB-Cu, both copper dendrites and sulfate precipitates were found on the surface of FR-4 (board material) between two plates. Moreover, the Cu dendrite was produced between the two plates and migrated toward cathode. Compared to PCB-Cu, PCB-ENIG exhibited a higher tendency of ECM failure and suffered from seriously short circuit failure under high relative humidity (RH) environment. SKP results demonstrated that surface potentials of the anode plates were greater than those of the cathode plates, and those potentials of the two plates exhibited a descending trend as the RH increased. At the end of the paper, an electrochemical migration corrosion failure model of PCB was proposed. PMID:28772497

  17. Simple and efficient full wave analysis of electromagnetic coupling in multilayer printed circuit board layouts

    NASA Astrophysics Data System (ADS)

    Abdul-Gaffoor, Mohammed Rajeek

    2000-09-01

    A simple method to model Printed Circuit Board (PCB) that takes advantage of the unique features found in PCBs is proposed. This method is capable of analyzing coupling between any nets in the entire multilayer PCB. Using the equivalence principle, the PCB is modeled as a cascade of parallel plate waveguides with half-space regions residing above and below the PCB. The problem is formulated using equivalent magnetic currents in the non- metallic regions of layer interfaces rather than in terms of electric currents in the planar metal layers. The equivalent magnetic currents at the dielectric interfaces are expressed in terms of the Rao-Wilton-Glisson (RWG) basis functions. The electric currents flowing on the vias inside dielectric layers are assumed constant in the vertical direction. These vertical electric currents radiate TEM modes in the parallel plate environment. Integral equations based on simple parallel plate and free-space Green's functions enforcing the boundary conditions are set up and solved using the Method of Moments. The equivalent magnetic currents in each layer interact only with currents in the adjacent layers, thereby resulting in a `` chained-block- banded'' matrix. Excitation is provided through ports defined at each pair of pads, or between a pad and nearby ground. These ports are located on the top and the bottom layers of the PCB where the circuit components and IC pins are mounted. Two different localized excitation schemes, one with a current loop injection and the other with a strip current excitation, are proposed. This formulation requires the computation of the MoM matrix once per frequency for any number of ports. Further, the solution for only those unknown equivalent magnetic currents around the port regions is required to obtain the N-port impedance parameter characterization of the PCB. Consequently, a memory efficient block matrix solution process can be used to solve problems of a large size for a given memory. Simple and

  18. Electrostatic separation for recovering metals and nonmetals from waste printed circuit board: problems and improvements.

    PubMed

    Wu, Jiang; Li, Jia; Xu, Zhenming

    2008-07-15

    Electrostatic separation is an effective and environmentally friendly method for recycling comminuted waste printed circuit boards (PCB). As a classical separator, the roll-type corona-electrostatic separator (RTS) has some advantages in this field. However, there are still some notable problems, such as the middling products and their further treatment, impurity of nonconductive products because of the aggregation of fine particles, and stability of the separation process and balance between the production capacity and the separation quality. To overcome these problems, a conception of two-step separation is presented, and a new two-roll type corona-electrostatic separator (T-RTS) was built As compared to RTS, the conductive products increase by 8.9%, the middling products decrease by 45%, and the production capacity increases by 50% in treating comminuted PCB wastes by T-RTS. In addition, the separation process in T-RTS is more stable. Therefore, T-RTS is a promising separator for recycling comminuted PCB.

  19. Dielectrophoresis-based cell manipulation using electrodes on a reusable printed circuit board.

    PubMed

    Park, Kidong; Suk, Ho-Jun; Akin, Demir; Bashir, Rashid

    2009-08-07

    Particle manipulation based on dielectrophoresis (DEP) can be a versatile and useful tool in lab-on-chip systems for a wide range of cell patterning and tissue engineering applications. Even though there are extensive reports on the use of DEP for cell patterning applications, the development of approaches that make DEP even more affordable and common place is still desirable. In this study, we present the use of interdigitated electrodes on a printed circuit board (PCB) that can be reused to manipulate and position HeLa cells and polystyrene particles over 100 microm thick glass cover slips using DEP. An open-well or a closed microfluidic channel, both made of PDMS, was placed on the glass coverslip, which was then placed directly over the PCB. An AC voltage was applied to the electrodes on the PCB to induce DEP on the particles through the thin glass coverslip. The HeLa cells patterned with DEP were subsequently grown to confirm the lack of any adverse affects from the electric fields. This alternative and reusable platform for DEP particle manipulation can provide a convenient and rapid method for prototyping a DEP-based lab-on-chip system, cost-sensitive lab-on-chip applications, and a wide range of tissue engineering applications.

  20. Bioleaching of copper from waste printed circuit boards by bacterial consortium enriched from acid mine drainage.

    PubMed

    Xiang, Yun; Wu, Pingxiao; Zhu, Nengwu; Zhang, Ting; Liu, Wen; Wu, Jinhua; Li, Ping

    2010-12-15

    The objectives of this study were to evaluate the solubility of copper in waste printed circuit boards (PCBs) by bacterial consortium enriched from natural acid mine drainage, and to determine optimum conditions of bioleaching copper from PCBs. The results indicated that the extraction of copper was mainly accomplished indirectly through oxidation by ferric ions generated from ferrous ion oxidation bacteria. The initial pH and Fe(2+) concentration played an important role in copper extraction and precipitate formation. The leaching rate of copper was generally higher at lower PCB powder dosage. Moreover, a two-step process was extremely necessary for bacterial growth and obtaining an appropriate Fe(2+) oxidation rate; a suitable time when 6.25 g/L of Fe(2+) remained in the solution was suggested for adding PCB powder. The maximum leaching rate of copper was achieved 95% after 5 days under the conditions of initial pH 1.5, 9 g/L of initial Fe(2+), and 20 g/L of PCB powder. All findings demonstrated that copper could be efficiently solubilized from waste PCBs by using bacterial consortium, and the leaching period was shortened remarkably from about 12 days to 5 days.

  1. Evaluation of a recycling process for printed circuit board by physical separation and heat treatment

    SciTech Connect

    Fujita, Toyohisa; Ono, Hiroyuki; Dodbiba, Gjergj; Yamaguchi, Kunihiko

    2014-07-15

    Highlights: • The parts mounted on printed circuit board (PCB) were liberated by underwater explosion and mechanical crushing. • The crushed PCB without surface-mounted parts was carbonized under inert atmosphere at 873 K to recover copper. • The multi-layered ceramic capacitors including nickel was carbonized at 873 K to recover nickel by the magnetic separation. • The tantalum powders were recovered from the molded resins by heat treatment at 723 and 823 K in air atmosphere and screening. • Energy and treatment cost of new process increased, however, the environmental burden decreased comparing conventional one. - Abstract: Printed circuit boards (PCBs) from discarded personal computer (PC) and hard disk drive were crushed by explosion in water or mechanical comminution in order to disintegrate the attached parts. More parts were stripped from PCB of PC, composed of epoxy resin; than from PCB of household appliance, composed of phenol resin. In an attempt to raise the copper grade of PCB by removing other components, a carbonization treatment was investigated. The crushed PCB without surface-mounted parts was carbonized under a nitrogen atmosphere at 873–1073 K. After screening, the char was classified by size into oversized pieces, undersized pieces and powder. The copper foil and glass fiber pieces were liberated and collected in undersized fraction. The copper foil was liberated easily from glass fiber by stamping treatment. As one of the mounted parts, the multi-layered ceramic capacitors (MLCCs), which contain nickel, were carbonized at 873 K. The magnetic separation is carried out at a lower magnetic field strength of 0.1 T and then at 0.8 T. In the +0.5 mm size fraction the nickel grade in magnetic product was increased from 0.16% to 6.7% and the nickel recovery is 74%. The other useful mounted parts are tantalum capacitors. The tantalum capacitors were collected from mounted parts. The tantalum-sintered bodies were separated from molded resins

  2. Visual positioning method of printed circuit boards based on spatial moments

    NASA Astrophysics Data System (ADS)

    Wang, Zujin; Huang, Xiaodiao

    2014-03-01

    With the increasing necessities for reliable printed circuit board (PCB) product, there has been a considerable demand for high-speed and high-precision vision positioning systems. To locate a PCB board with high accuracy and reliability with the positioning mark images, a new visual positioning method is introduced. Considering the limitations of Lyvers subpixel edge detection algorithm, such as the lower positioning accuracy, the larger errors at the neighborhood of the edge intersections, and the more computing time and the more cumbersome process of threshold selection, we propose an improved algorithm, in which coarse and accurate edge detection methods are adopted, and a new criterion is put forward to detect the edge points with Otsu method. Furthermore, a formula is developed to determine the edge intersections, whose subpixel coordinates are calculated with bilinear interpolation and conjugate gradient method. Additionally, the causes of principle errors are explored, and the error compensation formulas are derived at any angle edges of the three-level edge model. The last experimental results show that the improved algorithm has good versatility, and compared with Lyvers and Ghosal algorithm, the process of threshold selection is easier, the detected edges are thinner, and the positioning accuracy for all edge points is much higher.

  3. Modular integration of electronics and microfluidic systems using flexible printed circuit boards.

    PubMed

    Wu, Amy; Wang, Lisen; Jensen, Erik; Mathies, Richard; Boser, Bernhard

    2010-02-21

    Microfluidic systems offer an attractive alternative to conventional wet chemical methods with benefits including reduced sample and reagent volumes, shorter reaction times, high-throughput, automation, and low cost. However, most present microfluidic systems rely on external means to analyze reaction products. This substantially adds to the size, complexity, and cost of the overall system. Electronic detection based on sub-millimetre size integrated circuits (ICs) has been demonstrated for a wide range of targets including nucleic and amino acids, but deployment of this technology to date has been limited due to the lack of a flexible process to integrate these chips within microfluidic devices. This paper presents a modular and inexpensive process to integrate ICs with microfluidic systems based on standard printed circuit board (PCB) technology to assemble the independently designed microfluidic and electronic components. The integrated system can accommodate multiple chips of different sizes bonded to glass or PDMS microfluidic systems. Since IC chips and flex PCB manufacturing and assembly are industry standards with low cost, the integrated system is economical for both laboratory and point-of-care settings.

  4. Copper extraction from coarsely ground printed circuit boards using moderate thermophilic bacteria in a rotating-drum reactor

    SciTech Connect

    Rodrigues, Michael L.M.; Leão, Versiane A.; Gomes, Otavio; Lambert, Fanny; Bastin, David; Gaydardzhiev, Stoyan

    2015-07-15

    Highlights: • Copper bioleaching from PCB (20 mm) by moderate thermophiles was demonstrated. • Larger PCB sheets enable a cost reduction due to the elimination of fine grinding. • Crushing generated cracks in PCB increasing the copper extraction. • A pre-treatment step was necessary to remove the lacquer coating. • High copper extractions (85%) were possible with pulp density of up to 25.0 g/L. - Abstract: The current work reports on a new approach for copper bioleaching from Printed Circuit Board (PCB) by moderate thermophiles in a rotating-drum reactor. Initially leaching of PCB was carried out in shake flasks to assess the effects of particle size (−208 μm + 147 μm), ferrous iron concentration (1.25–10.0 g/L) and pH (1.5–2.5) on copper leaching using mesophile and moderate thermophile microorganisms. Only at a relatively low solid content (10.0 g/L) complete copper extraction was achieved from the particle size investigated. Conversely, high copper extractions were possible from coarse-ground PCB (20 mm-long) working with increased solids concentration (up to 25.0 g/L). Because there was as the faster leaching kinetics at 50 °C Sulfobacillus thermosulfidooxidans was selected for experiments in a rotating-drum reactor with the coarser-sized PCB sheets. Under optimal conditions, copper extraction reached 85%, in 8 days and microscopic observations by SEM–EDS of the on non-leached and leached material suggested that metal dissolution from the internal layers was restricted by the fact that metal surface was not entirely available and accessible for the solution in the case of the 20 mm-size sheets.

  5. Evaluation of a recycling process for printed circuit board by physical separation and heat treatment.

    PubMed

    Fujita, Toyohisa; Ono, Hiroyuki; Dodbiba, Gjergj; Yamaguchi, Kunihiko

    2014-07-01

    Printed circuit boards (PCBs) from discarded personal computer (PC) and hard disk drive were crushed by explosion in water or mechanical comminution in order to disintegrate the attached parts. More parts were stripped from PCB of PC, composed of epoxy resin; than from PCB of household appliance, composed of phenol resin. In an attempt to raise the copper grade of PCB by removing other components, a carbonization treatment was investigated. The crushed PCB without surface-mounted parts was carbonized under a nitrogen atmosphere at 873-1073 K. After screening, the char was classified by size into oversized pieces, undersized pieces and powder. The copper foil and glass fiber pieces were liberated and collected in undersized fraction. The copper foil was liberated easily from glass fiber by stamping treatment. As one of the mounted parts, the multi-layered ceramic capacitors (MLCCs), which contain nickel, were carbonized at 873 K. The magnetic separation is carried out at a lower magnetic field strength of 0.1T and then at 0.8 T. In the +0.5mm size fraction the nickel grade in magnetic product was increased from 0.16% to 6.7% and the nickel recovery is 74%. The other useful mounted parts are tantalum capacitors. The tantalum capacitors were collected from mounted parts. The tantalum-sintered bodies were separated from molded resins by heat treatment at 723-773 K in air atmosphere and screening of 0.5mm. Silica was removed and 70% of tantalum grade was obtained after more than 823K heating and separation. Next, the evaluation of Cu recycling in PCB is estimated. Energy consumption of new process increased and the treatment cost becomes 3 times higher comparing the conventional process, while the environmental burden of new process decreased comparing conventional process. The nickel recovery process in fine ground particles increased energy and energy cost comparing those of the conventional process. However, the environmental burden decreased than the conventional

  6. Effective electromagnetic shielding in multilayer printed circuit boards

    NASA Astrophysics Data System (ADS)

    Wiles, K. G.; Moe, J. L.

    Multilayer printed circuit boards have proven to be recurrent abettors of electromagnetic coupling problems created by the incessantly faster response times in integrated circuit technologies. Coupling within multilayer boards has not only inhibited meeting certain EMI requirements but has also precipitated 'self-inflicted' malfunctions commonly experienced during development of avionic systems. A recent avionic system, interfacing two asynchronous processors through a fourteen-layer motherboard, permitted coupling through ground plane connector apertures of sufficient amplitude and duration as to cause unintentional intercommunication and system malfunctions. The coupling mechanism and ground plane modifications which reduced this coupling by 40 dB and eliminated the incompatibility are discussed in this paper

  7. Printed circuit boards: a review on the perspective of sustainability.

    PubMed

    Canal Marques, André; Cabrera, José-María; Malfatti, Célia de Fraga

    2013-12-15

    Modern life increasingly requires newer equipments and more technology. In addition, the fact that society is highly consumerist makes the amount of discarded equipment as well as the amount of waste from the manufacture of new products increase at an alarming rate. Printed circuit boards, which form the basis of the electronics industry, are technological waste of difficult disposal whose recycling is complex and expensive due to the diversity of materials and components and their difficult separation. Currently, printed circuit boards have a fixing problem, which is migrating from traditional Pb-Sn alloys to lead-free alloys without definite choice. This replacement is an attempt to minimize the problem of Pb toxicity, but it does not change the problem of separation of the components for later reuse and/or recycling and leads to other problems, such as temperature rise, delamination, flaws, risks of mechanical shocks and the formation of "whiskers". This article presents a literature review on printed circuit boards, showing their structure and materials, the environmental problem related to the board, some the different alternatives for recycling, and some solutions that are being studied to reduce and/or replace the solder, in order to minimize the impact of solder on the printed circuit boards.

  8. Stripline/Microstrip Transition in Multilayer Circuit Board

    NASA Technical Reports Server (NTRS)

    Epp, Larry; Khan, Abdur

    2005-01-01

    A stripline-to-microstrip transition has been incorporated into a multilayer circuit board that supports a distributed solid-state microwave power amplifier, for the purpose of coupling the microwave signal from a buried-layer stripline to a top-layer microstrip. The design of the transition could be adapted to multilayer circuit boards in such products as cellular telephones (for connecting between circuit-board signal lines and antennas), transmitters for Earth/satellite communication systems, and computer mother boards (if processor speeds increase into the range of tens of gigahertz). The transition is designed to satisfy the following requirements in addition to the basic coupling requirement described above: (1) The transition must traverse multiple layers, including intermediate layers that contain DC circuitry. (2) The transition must work at a frequency of 32 GHz with low loss and low reflection. (3) The power delivered by the transition to top-layer microstrip must be split equally in opposite directions along the microstrip. Referring to the figure, this amounts to a requirement that when power is supplied to input port 1, equal amounts of power flow through output ports 2 and 3. (4) The signal-line via that is necessarily a part of such a transition must not be what is known in the art as a blind via; that is, it must span the entire thickness of the circuit board.

  9. Double sided circuit board and a method for its manufacture

    DOEpatents

    Lindenmeyer, Carl W.

    1989-07-04

    Conductance between the sides of a large double sided printed circuit board is provided using a method which eliminates the need for chemical immersion or photographic exposure of the entire large board. A plurality of through-holes are drilled or punched in a substratum according to the desired pattern, conductive laminae are made to adhere to both sides of the substratum covering the holes and the laminae are pressed together and permanently joined within the holes, providing conductive paths.

  10. Double sided circuit board and a method for its manufacture

    DOEpatents

    Lindenmeyer, Carl W.

    1989-01-01

    Conductance between the sides of a large double sided printed circuit board is provided using a method which eliminates the need for chemical immersion or photographic exposure of the entire large board. A plurality of through-holes are drilled or punched in a substratum according to the desired pattern, conductive laminae are made to adhere to both sides of the substratum covering the holes and the laminae are pressed together and permanently joined within the holes, providing conductive paths.

  11. Double sided circuit board and a method for its manufacture

    DOEpatents

    Lindenmeyer, C.W.

    1988-04-14

    Conductance between the sides of a large double sided printed circuit board is provided using a method which eliminates the need for chemical immersion or photographic exposure of the entire large board. A plurality of through-holes are drilled or punched in a substratum according to the desired pattern, conductive laminae are made to adhere to both sides of the substratum covering the holes and the laminae are pressed together and permanently joined within the holes, providing conductive paths. 4 figs.

  12. Mapping Small Intestine Bioelectrical Activity Using High-Resolution Printed-Circuit-Board Electrodes

    PubMed Central

    Angeli, Timothy R.; O’Grady, Gregory; Erickson, Jonathan C.; Du, Peng; Paskaranandavadivel, Niranchan; Bissett, Ian P.; Cheng, Leo K.; Pullan, Andrew J.

    2014-01-01

    In this study, novel methods were developed for the in-vivo high-resolution recording and analysis of small intestine bioelectrical activity, using flexible printed-circuit-board (PCB) electrode arrays. Up to 256 simultaneous recordings were made at multiple locations along the porcine small intestine. Data analysis was automated through the application and tuning of the Falling-Edge Variable-Threshold algorithm, achieving 92% sensitivity and a 94% positive-predictive value. Slow wave propagation patterns were visualized through the automated generation of animations and isochronal maps. The methods developed and validated in this study are applicable for use in humans, where future studies will serve to improve the clinical understanding of small intestine motility in health and disease. PMID:22255449

  13. Mapping small intestine bioelectrical activity using high-resolution printed-circuit-board electrodes.

    PubMed

    Angeli, Timothy R; O'Grady, Gregory; Erickson, Jonathan C; Du, Peng; Paskaranandavadivel, Niranchan; Bissett, Ian P; Cheng, Leo K; Pullan, Andrew J

    2011-01-01

    In this study, novel methods were developed for the in-vivo high-resolution recording and analysis of small intestine bioelectrical activity, using flexible printed-circuit-board (PCB) electrode arrays. Up to 256 simultaneous recordings were made at multiple locations along the porcine small intestine. Data analysis was automated through the application and tuning of the Falling-Edge Variable-Threshold algorithm, achieving 92% sensitivity and a 94% positive-predictive value. Slow wave propagation patterns were visualized through the automated generation of animations and isochronal maps. The methods developed and validated in this study are applicable for use in humans, where future studies will serve to improve the clinical understanding of small intestine motility in health and disease.

  14. Note: Design and construction of a simple and reliable printed circuit board-substrate Bradbury-Nielsen gate for ion mobility spectrometry

    NASA Astrophysics Data System (ADS)

    Du, Yongzhai; Cang, Huaiwen; Wang, Weiguo; Han, Fenglei; Chen, Chuang; Li, Lin; Hou, Keyong; Li, Haiyang

    2011-08-01

    A less laborious, structure-simple, and performance-reliable printed circuit board (PCB) based Bradbury-Nielsen gate for high-resolution ion mobility spectrometry was introduced and investigated. The gate substrate was manufactured using a PCB etching process with small holes (Φ 0.1 mm) drilled along the gold-plated copper lines. Two interdigitated sets of rigid stainless steel spring wire (Φ 0.1 mm) that stands high temperature and guarantees performance stability were threaded through the holes. Our homebuilt ion mobility spectrometer mounted with the gate gave results of about 40 for resolution while keeping a signal intensity of over 0.5 nano-amperes.

  15. Note: Design and construction of a simple and reliable printed circuit board-substrate Bradbury-Nielsen gate for ion mobility spectrometry.

    PubMed

    Du, Yongzhai; Cang, Huaiwen; Wang, Weiguo; Han, Fenglei; Chen, Chuang; Li, Lin; Hou, Keyong; Li, Haiyang

    2011-08-01

    A less laborious, structure-simple, and performance-reliable printed circuit board (PCB) based Bradbury-Nielsen gate for high-resolution ion mobility spectrometry was introduced and investigated. The gate substrate was manufactured using a PCB etching process with small holes (Φ 0.1 mm) drilled along the gold-plated copper lines. Two interdigitated sets of rigid stainless steel spring wire (Φ 0.1 mm) that stands high temperature and guarantees performance stability were threaded through the holes. Our homebuilt ion mobility spectrometer mounted with the gate gave results of about 40 for resolution while keeping a signal intensity of over 0.5 nano-amperes.

  16. Biodegradable materials for multilayer transient printed circuit boards.

    PubMed

    Huang, Xian; Liu, Yuhao; Hwang, Suk-Won; Kang, Seung-Kyun; Patnaik, Dwipayan; Cortes, Jonathan Fajardo; Rogers, John A

    2014-11-19

    Biodegradable printed circuit boards based on water-soluble materials are demonstrated. These systems can dissolve in water within 10 mins to yield end-products that are environmentally safe. These and related approaches have the potential to reduce hazardous waste streams associated with electronics disposal.

  17. Testing of printed circuit board solder joints by optical correlation

    NASA Technical Reports Server (NTRS)

    Espy, P. N.

    1975-01-01

    An optical correlation technique for the nondestructive evaluation of printed circuit board solder joints was evaluated. Reliable indications of induced stress levels in solder joint lead wires are achievable. Definite relations between the inherent strength of a solder joint, with its associated ability to survive stress, are demonstrable.

  18. Circuit board design for good electromagnetic compatibility performance.

    PubMed

    Bearpark, J

    2005-10-01

    Design engineers need to consider the electromagnetic performance of printed circuit boards to adhere to electromagnetic compatibility requirements. This article examines factors that influence performance and outlines techniques to avoid the use of overly expensive screen enclosures in order to comply with the standards.

  19. Electrostatic separation for recycling waste printed circuit board: a study on external factor and a robust design for optimization.

    PubMed

    Hou, Shibing; Wu, Jiang; Qin, Yufei; Xu, Zhenming

    2010-07-01

    Electrostatic separation is an effective and environmentally friendly method for recycling waste printed circuit board (PCB) by several kinds of electrostatic separators. However, some notable problems have been detected in its applications and cannot be efficiently resolved by optimizing the separation process. Instead of the separator itself, these problems are mainly caused by some external factors such as the nonconductive powder (NP) and the superficial moisture of feeding granule mixture. These problems finally lead to an inefficient separation. In the present research, the impacts of these external factors were investigated and a robust design was built to optimize the process and to weaken the adverse impact. A most robust parameter setting (25 kv, 80 rpm) was concluded from the experimental design. In addition, some theoretical methods, including cyclone separation, were presented to eliminate these problems substantially. This will contribute to efficient electrostatic separation of waste PCB and make remarkable progress for industrial applications.

  20. New printed circuit boards magnetic coils in the vacuum vessel of J-TEXT tokamak for position measurement.

    PubMed

    Qiu, S S; Zhuang, G; Zhang, M; Xia, D H; Rao, B; Zhang, X Q; Pan, Y; Gentle, K

    2010-10-01

    Four sets of magnetic diagnostic coils, which are printed on machinable ceramic printed circuit boards (PCB), are designed, fabricated, installed, and tested in the Joint Texas Experimental Tokamak (J-TEXT) vacuum vessel for detecting the plasma radial and vertical displacements relative to the geometric center of the vacuum vessel in Ohmic discharges. Each coordinate is determined by a pair of variable cross-section Rogowski and saddle coils, which measure the tangential and normal magnetic fields (relative to the coil surface). These coils are suitable for mass production and offer advantages in vacuum compatibility and temperature tolerance that are important for J-TEXT. Position measurements using PCB coils are compared with those from soft x-ray image system and match the position well.

  1. New printed circuit boards magnetic coils in the vacuum vessel of J-TEXT tokamak for position measurement

    SciTech Connect

    Qiu, S. S.; Zhuang, G.; Zhang, M.; Xia, D. H.; Rao, B.; Zhang, X. Q.; Pan, Y.; Gentle, K.

    2010-10-15

    Four sets of magnetic diagnostic coils, which are printed on machinable ceramic printed circuit boards (PCB), are designed, fabricated, installed, and tested in the Joint Texas Experimental Tokamak (J-TEXT) vacuum vessel for detecting the plasma radial and vertical displacements relative to the geometric center of the vacuum vessel in Ohmic discharges. Each coordinate is determined by a pair of variable cross-section Rogowski and saddle coils, which measure the tangential and normal magnetic fields (relative to the coil surface). These coils are suitable for mass production and offer advantages in vacuum compatibility and temperature tolerance that are important for J-TEXT. Position measurements using PCB coils are compared with those from soft x-ray image system and match the position well.

  2. Sampling and Control Circuit Board for an Inertial Measurement Unit

    NASA Technical Reports Server (NTRS)

    Chelmins, David; Powis, Rick

    2012-01-01

    Spacesuit navigation is one component of NASA s efforts to return humans to the Moon. Studies performed at the NASA Glenn Research Center (GRC) considered various navigation technologies and filtering approaches to enable navigation on the lunar surface. As part of this effort, microelectromechanical systems (MEMS) inertial measurement units (IMUs) were studied to determine if they could supplement a radiometric infrastructure. MEMS IMUs were included in the Lunar Extra-Vehicular Activity Crewmember Location Determination System (LECLDS) testbed during NASA s annual Desert Research and Technology Studies (D-RATS) event in 2009 and 2010. The testbed included one IMU in 2009 and three IMUs in 2010, along with a custom circuit board interfacing between the navigation processor and each IMU. The board was revised for the 2010 test, and this paper documents the design details of this latest revision of the interface circuit board and firmware.

  3. The determination of the thickness of the layers deposited on the electronic circuit boards through tribological methods

    NASA Astrophysics Data System (ADS)

    Petrescu, A. M.; Tudor, A.; Chişiu, G.; Stoica, N. A.; Cihak Bayr, U.

    2017-02-01

    The purpose of the paper is to determinate the thickness of the copper layer deposit on the electronic circuit boards, the thickness of the soldering alloy SAC 307 (96.5%Sn/3.0%Ag/0.7%Cu) deposit on the copper-PCB assembly used in electronic industry and also to determinate the sliding length of the sphere on those materials. Slurry composed of water and SiC was used to reduce the testing time. For the experiment a CSEM Calowear equipment was used and the tested materials were the layer of FR4(flame retardant 4) with copper deposit and the soldering alloy SAC 307.

  4. Copper extraction from coarsely ground printed circuit boards using moderate thermophilic bacteria in a rotating-drum reactor.

    PubMed

    Rodrigues, Michael L M; Leão, Versiane A; Gomes, Otavio; Lambert, Fanny; Bastin, David; Gaydardzhiev, Stoyan

    2015-07-01

    The current work reports on a new approach for copper bioleaching from Printed Circuit Board (PCB) by moderate thermophiles in a rotating-drum reactor. Initially leaching of PCB was carried out in shake flasks to assess the effects of particle size (-208μm+147μm), ferrous iron concentration (1.25-10.0g/L) and pH (1.5-2.5) on copper leaching using mesophile and moderate thermophile microorganisms. Only at a relatively low solid content (10.0g/L) complete copper extraction was achieved from the particle size investigated. Conversely, high copper extractions were possible from coarse-ground PCB (20mm-long) working with increased solids concentration (up to 25.0g/L). Because there was as the faster leaching kinetics at 50°C Sulfobacillus thermosulfidooxidans was selected for experiments in a rotating-drum reactor with the coarser-sized PCB sheets. Under optimal conditions, copper extraction reached 85%, in 8days and microscopic observations by SEM-EDS of the on non-leached and leached material suggested that metal dissolution from the internal layers was restricted by the fact that metal surface was not entirely available and accessible for the solution in the case of the 20mm-size sheets. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Suppressing effect of calcium-based waste on control of bromine flux during the pyrolysis of printed circuit boards.

    PubMed

    Jie, Guan; Min, Xu; Wu, Wenjie; Zhang, Chenglong; Wang, Jingwei; Bai, Jianfeng

    2012-11-01

    The effect of calcium-based addition on the brominate flux during printed circuit board (PCB) pyrolysis was investigated. It was found that bromine (Br) can be effectively fixed in solid phase during PCB pyrolysis by adding calcium-based waste materials. Phenol and 4-ethylphenol are the major products of pyrolysis. When the two kinds of red mud were used as additive, their content was 85.25 and 84.81%, respectively, which was higher than others. The 2-bromophenol and 2-bromo-4-methyl-benzene are the main Br-containing pyrolysis volatiles. After adding calcium-based additive, these two volatiles were apparently reduced and only small amounts of 2-bromo-4-methyl-benzene were detected in the products, namely 0.71 and 0.86%, respectively for the two kinds of red mud. Hence, no matter from the perspective of product use or simple Br-fixing, the bromine in the three-phase products can be effectively regulated and controlled by adding calcium-based waste residue during PCB pyrolysis. Finally, the Br-fixing mechanism was analysed. As a result, when calcium-based waste materials were added to the PCB pyrolysis it made bromine fix easily in the resident yielding a byproduct that can be further used.

  6. Preparation of hierarchical porous carbon from waste printed circuit boards for high performance electric double-layer capacitors

    NASA Astrophysics Data System (ADS)

    Du, Xuan; Wang, Li; Zhao, Wei; Wang, Yi; Qi, Tao; Li, Chang Ming

    2016-08-01

    Renewable clean energy and resources recycling have become inevitable choices to solve worldwide energy shortages and environmental pollution problems. It is a great challenge to recycle tons of waste printed circuit boards (PCB) produced every year for clean environment while creating values. In this work, low cost, high quality activated carbons (ACs) were synthesized from non-metallic fractions (NMF) of waste PCB to offer a great potential for applications of electrochemical double-layer capacitors (EDLCs). After recovering metal from waste PCB, hierarchical porous carbons were produced from NMF by carbonization and activation processes. The experimental results exhibit that some pores were formed after carbonization due to the escape of impurity atoms introduced by additives in NMF. Then the pore structure was further tailored by adjusting the activation parameters. Roles of micropores and non-micropores in charge storage were investigated when the hierarchical porous carbons were applied as electrode of EDLCs. The highest specific capacitance of 210 F g-1 (at 50 mA g-1) and excellent rate capability were achieved when the ACs possessing a proper micropores/non-micropores ratio. This work not only provides a promising method to recycle PCB, but also investigates the structure tailoring arts for a rational hierarchical porous structure in energy storage/conversion.

  7. Exhaust constituent emission factors of printed circuit board pyrolysis processes and its exhaust control.

    PubMed

    Chiang, Hung-Lung; Lin, Kuo-Hsiung

    2014-01-15

    The printed circuit board (PCB) is an important part of electrical and electronic equipment, and its disposal and the recovery of useful materials from waste PCBs (WPCBs) are key issues for waste electrical and electronic equipment. Waste PCB compositions and their pyrolysis characteristics were analyzed in this study. In addition, the volatile organic compound (VOC) exhaust was controlled by an iron-impregnated alumina oxide catalyst. Results indicated that carbon and oxygen were the dominant components (hundreds mg/g) of the raw materials, and other elements such as nitrogen, bromine, and copper were several decades mg/g. Exhaust constituents of CO, H2, CH4, CO2, and NOx, were 60-115, 0.4-4.0, 1.1-10, 30-95, and 0-0.7mg/g, corresponding to temperatures ranging from 200 to 500°C. When the pyrolysis temperature was lower than 300°C, aromatics and paraffins were the major species, contributing 90% of ozone precursor VOCs, and an increase in the pyrolysis temperature corresponded to a decrease in the fraction of aromatic emission factors. Methanol, ethylacetate, acetone, dichloromethane, tetrachloromethane and acrylonitrile were the main species of oxygenated and chlorinated VOCs. The emission factors of some brominated compounds, i.e., bromoform, bromophenol, and dibromophenol, were higher at temperatures over 400°C. When VOC exhaust was flowed through the bed of Fe-impregnated Al2O3, the emission of ozone precursor VOCs could be reduced by 70-80%.

  8. Corrosion Behavior of Silver-Plated Circuit Boards in a Simulated Marine Environment with Industrial Pollution

    PubMed Central

    Xiao, Kui; Yi, Pan; Yan, Lidan; Bai, Ziheng; Dong, Chaofang; Dong, Pengfei; Gao, Xiong

    2017-01-01

    The electrochemical corrosion behavior of a silver-plated circuit board (PCB-ImAg) in a polluted marine atmosphere environment (Qingdao in China) is studied through a simulated experiment. The morphologies of PCB-ImAg show some micropores on the surface that act as the corrosion-active points in the tests. Cl− mainly induces microporous corrosion, whereas SO2 causes general corrosion. Notably, the silver color changes significantly under SO2 influence. EIS results show that the initial charge transfer resistance in the test containing SO2 and Cl− is 9.847 × 103, while it is 3.701 × 104 in the test containing Cl− only, which demonstrates that corrosion accelerates in a mixed atmosphere. Polarization curves further show that corrosion potential is lower in mixed solutions (between −0.397 V SCE and −0.214 V SCE) than it in the solution containing Cl− only (−0.168 V SCE), indicating that corrosion tendency increases with increased HSO3− concentration. PMID:28773121

  9. Laser ablated coupling structures for stacked optical interconnections on printed circuit boards

    NASA Astrophysics Data System (ADS)

    Hendrickx, Nina; Van Steenberge, Geert; Geerinck, Peter; Van Erps, Jürgen; Thienpont, Hugo; Van Daele, Peter

    2006-04-01

    Laser ablation is presented as a versatile technology that can be used for the definition of arrays of multimode waveguides and coupling structures in a stacked two layer optical structure, integrated on a printed circuit board (PCB). The optical material, Truemode Backplane TM Polymer, is fully compatible with standard PCB manufacturing and shows excellent ablation properties. A KrF excimer laser is used for the ablation of both waveguides and coupling structures into the optical layer. The stacking of individual optical layers containing waveguides, that guide the light in the plane of the optical layer, and coupling structures, that provide out-of-plane coupling and coupling between different optical layers, is very interesting since it allows us to increase the integration density and routing possibilities and limit the number of passive components that imply a certain loss. Experimental results are presented, and surface roughness and profile measurements are performed on the structured elements for further characterization. Numerical simulations are presented on the tolerance on the angle of the coupling structures and the influence of tapering on the coupling efficiency of the waveguides.

  10. Interfacial and mechanical property analysis of waste printed circuit boards subject to thermal shock.

    PubMed

    Li, Jinhui; Duan, Huabo; Yu, Keli; Wang, Siting

    2010-02-01

    Waste printed circuit boards (PCBs) are the focal points for handling electric and electronic waste. In this paper, a thermal shock method was used to pretreat waste PCBs for the improvement of crushing performance. The influence of the thermal shock process on interfacial modification and mechanical property attenuation of PCB waste was studied. The appearance and layer spacing of the basal plane began to change slightly when the temperature reached 200 degrees C. By 250 degrees C, apparent bulging, cracking, and delamination were observed. However, pyrolysis of PCBs occurred when the temperature reached 275 degrees C, where PCBs were carbonized. The thermogravimetric analysis of PCB particles under vacuum showed that 270 degrees C was the starting point of pyrolysis. The tensile and impact strength of PCBs were reduced as shock temperature rose gradually, with a reduction by 2.6 and 16.5%, respectively, at 250 degrees C from its unheated strength. The PCBs that were heated to 250 degrees C achieved 100% liberation, increasing linearly from 13.6% for unheated PCBs through a single-level shear-crusher (2-mm mesh) and resulting in an obvious reduction of 9.5% (dB) in dust and noise at 250 degrees C. These parameters could be helpful for establishing the operational setup for industrial-scale facilities with the aim of achieving a compact process and a highly efficient recovery for waste PCBs compared with those of the traditional combination mechanical technologies.

  11. The ultrasonically assisted metals recovery treatment of printed circuit board waste sludge by leaching separation.

    PubMed

    Xie, Fengchun; Li, Haiying; Ma, Yang; Li, Chuncheng; Cai, Tingting; Huang, Zhiyuan; Yuan, Gaoqing

    2009-10-15

    This paper provides a practical technique that realized industrial scale copper and iron separation from printed circuit board (PCB) waste sludge by ultrasonically assisted acid leaching in a low cost, low energy consumption and zero discharge of wastes manner. The separation efficiencies of copper and iron from acid leaching with assistance of ultrasound were compared with the one without assistance of ultrasound and the effects of the leaching procedure, pH value, and ultrasonic strength have been investigated in the paper. With the appropriate leaching procedure, a final pH of 3.0, an ultrasonic generator power of 160 W (in 1l tank), leaching time of 60 min, leaching efficiencies of copper and iron had reached 97.83% and 1.23%, respectively. Therefore the separation of copper and iron in PCB waste sludge was virtually achieved. The lab results had been successfully applied to the industrial scaled applications in a heavy metal recovery plant in city of Huizhou, China for more than two years. It has great potentials to be used in even the broad metal recovery practices.

  12. 77 FR 61025 - Certain Prepregs, Laminates, and Finished Circuit Boards: Notice of Institution of Formal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-05

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Prepregs, Laminates, and Finished Circuit Boards: Notice of Institution of Formal... States after importation of certain prepregs, laminates, and finished circuit boards that infringe...

  13. Investigation of Solder Cracking Problems on Printed Circuit Boards

    NASA Technical Reports Server (NTRS)

    Berkebile, M. J.

    1967-01-01

    A Solder Committee designated to investigate a solder cracking phenomena occurring on the SATURN electrical/electronic hardware found the cause to be induced stress in the soldered connections rather than faulty soldering techniques. The design of the printed circuit (PC) board assemblies did not allow for thermal expansion of the boards that occurred during normal operation. The difference between the thermal expansion properties of the boards and component lead materials caused stress and cracking in the soldered connections. The failure mechanism and various PC boards component mounting configurations are examined in this report. Effective rework techniques using flanged tubelets, copper tubelets, and soft copper wiring are detailed. Future design considerations to provide adequate strain relief in mounting configurations are included to ensure successful solder terminations.

  14. Research on dynamic model of printed circuit board based on finite element method

    NASA Astrophysics Data System (ADS)

    Wei, Hui; Xu, Liangjun

    2017-08-01

    The vibration characteristics of printed circuit boards are related to the reliability of electronic components installed on their surface. Finite element software is a powerful tool to analyze the vibration characteristics of printed circuit boards, and the correct establishment of finite element model is very important. In this paper, the dynamic model of anisotropic printed circuit board is established by analyzing the material properties of printed circuit board. The influence of boundary condition and lumped mass on the vibration characteristics of printed circuit board is analyzed. In order to establish a more realistic printed circuit The finite element model of the plate provides the necessary basis.

  15. Evaluation of gold and silver leaching from printed circuit board of cellphones

    SciTech Connect

    Petter, P.M.H. Veit, H.M.; Bernardes, A.M.

    2014-02-15

    Highlights: • Printed circuit boards (PCB) of mobile phones have large amounts of metals with high economic value such as gold and silver. • Dissolution of gold was done with a cyanide-based reagent and silver with nitric acid. • Leaching of PCB with Na{sub 2}S{sub 2}O{sub 3} and (NH{sub 4}){sub 2}S{sub 2}O{sub 3} to examine the feasibility of using these reagents was done. - Abstract: Electronic waste has been increasing proportionally with the technology. So, nowadays, it is necessary to consider the useful life, recycling, and final disposal of these equipment. Metals, such as Au, Ag, Cu, Sn and Ni can be found in the printed circuit boards (PCB). According to this, the aims of this work is to characterize the PCBs of mobile phones with aqua regia; obtaining “reference” values of leaching, to gold and silver, with cyanide and nitric acid, respectively; and study the process of leaching of these metals in alternative leaching with sodium thiosulfate and ammonium thiosulfate. The metals were characterized by digesting the sample with aqua regia for 1 and 2 h at 60 °C and 80 °C. The leaching of Au with a commercial reagent (cyanide) and the Ag with HNO{sub 3}were made. The leaching of Au and Ag with alternative reagents: Na{sub 2}S{sub 2}O{sub 3,} and (NH{sub 4}){sub 2}S{sub 2}O{sub 3} in 0.1 M concentration with the addition of CuSO{sub 4}, NH{sub 4}OH, and H{sub 2}O{sub 2}, was also studied. The results show that the digestion with aqua regia was efficient to characterize the metals present in the PCBs of mobile phones. However, the best method to solubilize silver was by digesting the sample with nitric acid. The leaching process using sodium thiosulfate was more efficient when an additional concentration of 0.015 and 0.030 M of the CuSO{sub 4} was added.

  16. Coaxial connector for use with printed circuit board edge connector

    DOEpatents

    Howard, Donald R.; MacGill, Robert A.

    1989-01-01

    A coaxial cable connector for interfacing with an edge connector for a printed circuit board whereby a coaxial cable can be interconnected with a printed circuit board through the edge connector. The coaxial connector includes a body having two leg portions extending from one side for receiving the edge connector therebetween, and a tubular portion extending from an opposing side for receiving a coaxial cable. A cavity within the body receives a lug of the edge connector and the center conductor of the coaxial cable. Adjacent lugs of the edge connector can be bend around the edge connector housing to function as spring-loaded contacts for receiving the coaxial connector. The lugs also function to facilitate shielding of the center conductor where fastened to the edge connector lug.

  17. Low-cost TO-CAN package combined with flexible and hard printed circuit boards for 25-Gb/s optical subassembly modules

    NASA Astrophysics Data System (ADS)

    Jou, Jau-Ji; Shih, Tien-Tsorng; Wu, Cheng-Ying; Su, Zhe-Xian

    2017-02-01

    A low-cost transistor outline-CAN (TO-CAN) package, which is combined with flexible printed circuit board (PCB) and hard PCB, has been developed for a 25-Gb/s optical subassembly module. On the flexible PCB, the transmission line structure used top ground microstrip line, and the wider transmission bandwidth can be obtained. Using ground pads and ground notch technologies, the impedance of connection between flexible PCB and hard PCB was designed to match with the impedances of signal traces of the flexible and hard PCBs. In the TO-CAN package, a TO-46 header was used, and the header needs to closely connect with the flexible PCB. The bandwidth of TO-46 package combined with flexible and hard PCBs can achieve above 23 GHz. The clear 25-Gb/s transmission eye diagram was also measured, and the rise time, fall time, and Q-factor of the eye diagram are 13.78, 13.56 ps, and 8.76, respectively. The TO-46 package combined with flexible and hard PCBs has been verified to be suitable for application in 25-Gb/s optical subassembly modules.

  18. Pollution prevention assessment for a printed circuit board plant

    SciTech Connect

    Edwards, H.W.; Kostrzewa, M.F.; Looby, G.P.

    1995-09-01

    The US Environmental Protection Agency (EPA) has funded a pilot project to assist small and medium-size manufacturers who want to minimize their generation of waste but who lack the expertise to do so. In an effort to assist these manufacturers Waste Minimization Assessment Centers (WMACs) were established at selected universities and procedures were adapted from the EPA Waste Minimization Opportunity Assessment Manual. The WMAC team at Colorado State University performed an assessment at a plant that manufacturers printed circuit boards. Templates for the circuit design are generated from customer-supplied circuit information. Copper/epoxy laminates and copper foil are cut into blank boards and layers. Circuit patterns are generated through a series of photolithographic and plating processes. The team`s report, detailing findings and recommendations, indicated that the onsite ion-exchange treatment of metal-containing rinse water generates regenerant solutions that could be further treated by electrowinning to recover metals and to achieve significant cost savings. This Research Brief was developed by the principal investigators and EPA`s National Risk Management Research Laboratory, Cincinnati, OH, to announce key findings of an ongoing research project that is fully documented in a separate report of the same title available from University City Science Center.

  19. An Investigation into the Package and Printed Circuit Board Assembly Solutions of an Ultrathin Coreless Flip-Chip Substrate

    NASA Astrophysics Data System (ADS)

    Chang, Jing-Yao; Chaung, Tung-Han; Chang, Tao-Chih

    2015-10-01

    Flip-chip technology has been widely accepted as a solution for electronic packaging of high-pin-count devices. Due to the demand for smaller and thinner package dimensions, coreless build-up substrates will be used in industry to carry the die by solder bumps due to the advantages of shorter transmission route and lower inductance and thermal resistance. However, coefficient of thermal expansion (CTE) mismatch between the Cu trace and the laminate often causes the coreless substrate to warp, which leads to failures such as nonwetted solder bumps and interfacial cracking during assembly and reliability tests. In a previous study, assembly of a six-layer polyimide-based coreless flip-chip package was achieved by a 17 mm × 17 mm die with 4355 Sn-37Pb solder bumps, an amide-based underfill, and 1521 Sn-3.0Ag-0.5Cu solder balls. For determination of its board-level reliability characteristics, the component was mounted on a printed circuit board (PCB) using a conventional surface mount technology, and 10 test vehicles were assembled for assessment of their reliability under a temperature cycling environment. The experimental results show that the characteristic life of the PCB assembly exceeded 1500 cycles and that failure resulted from fracture of the outermost solder balls on the substrate side. This was different from the failure mode of die cracking when the package experienced hundreds of temperature cycles at the component level because the rigid PCB, through solder balls, moderated the deformation of the coreless flip-chip package. Hence, the concentrated bending stress at the die edge region was lowered. Finally, the local CTE mismatch between the stiffener and the PCB dominated the fatigue fracture of the outermost solder balls to become the main failure mode.

  20. PCB Fault Detection Using Image Processing

    NASA Astrophysics Data System (ADS)

    Nayak, Jithendra P. R.; Anitha, K.; Parameshachari, B. D., Dr.; Banu, Reshma, Dr.; Rashmi, P.

    2017-08-01

    The importance of the Printed Circuit Board inspection process has been magnified by requirements of the modern manufacturing environment where delivery of 100% defect free PCBs is the expectation. To meet such expectations, identifying various defects and their types becomes the first step. In this PCB inspection system the inspection algorithm mainly focuses on the defect detection using the natural images. Many practical issues like tilt of the images, bad light conditions, height at which images are taken etc. are to be considered to ensure good quality of the image which can then be used for defect detection. Printed circuit board (PCB) fabrication is a multidisciplinary process, and etching is the most critical part in the PCB manufacturing process. The main objective of Etching process is to remove the exposed unwanted copper other than the required circuit pattern. In order to minimize scrap caused by the wrongly etched PCB panel, inspection has to be done in early stage. However, all of the inspections are done after the etching process where any defective PCB found is no longer useful and is simply thrown away. Since etching process costs 0% of the entire PCB fabrication, it is uneconomical to simply discard the defective PCBs. In this paper a method to identify the defects in natural PCB images and associated practical issues are addressed using Software tools and some of the major types of single layer PCB defects are Pattern Cut, Pin hole, Pattern Short, Nick etc., Therefore the defects should be identified before the etching process so that the PCB would be reprocessed. In the present approach expected to improve the efficiency of the system in detecting the defects even in low quality images

  1. Printed Circuit Board Assembly for Use in Space Missions

    NASA Technical Reports Server (NTRS)

    Petrick, David J. (Inventor); Vo, Luan (Inventor); Albaijes, Dennis (Inventor)

    2017-01-01

    An electronic assembly for use in space missions that includes a PCB and one or more multi-pin CGA devices coupled to the PCB. The PCB has one or more via-in-pad features and each via-in-pad feature comprises a land pad configured to couple a pin of the one or more multi-pin CGA devices to the via. The PCB also includes a plurality of layers arranged symmetrically in a two-halves configuration above and below a central plane of the PCB.

  2. Thermal research of infrared sight signal processing circuit board under temperature shock environment

    NASA Astrophysics Data System (ADS)

    Gao, Youtang; Ding, Huang; Qiao, Jianliang; Xu, Yuan; Niu, Jun

    2015-10-01

    Thermal stability technology of signal processing circuit infrared sight is studied under temperature shock. Model parameters and geometry is configured for FPGA devices (EP1C20F400C8), solder material and PCB. Signal circuit boards of full array BGA distribution are simulated and analyzed by thermal shock and waveform through engineering finite element analysis software. Because solders of the whole model have strong stress along Y direction, initial stress constraints along Y direction are primarily considered when the partial model of single solder is imposed by thermal load. When absolute thermal loads stresses of diagonal nodes with maximum strains are separated from the whole model, interpolation is processed according to thermal loads circulation. Plastic strains and thermal stresses of nodes in both sides of partial model are obtained. The analysis results indicate that with thermal load circulation, maximum forces of each circulation along Y direction are increasingly enlarged and with the accumulation of plastic strains of danger point, the composition will become invalid in the end.

  3. High-resolution Mapping of In Vivo Gastrointestinal Slow Wave Activity Using Flexible Printed Circuit Board Electrodes: Methodology and Validation

    PubMed Central

    DU, PENG; O'GRADY, G.; EGBUJI, J. U.; LAMMERS, W. J.; BUDGETT, D.; NIELSEN, P.; WINDSOR, J. A.; PULLAN, A. J.; CHENG, L. K.

    2014-01-01

    High-resolution, multi-electrode mapping is providing valuable new insights into the origin, propagation, and abnormalities of gastrointestinal (GI) slow wave activity. Construction of high-resolution mapping arrays has previously been a costly and time-consuming endeavor, and existing arrays are not well suited for human research as they cannot be reliably and repeatedly sterilized. The design and fabrication of a new flexible printed circuit board (PCB) multi-electrode array that is suitable for GI mapping is presented, together with its in vivo validation in a porcine model. A modified methodology for characterizing slow waves and forming spatiotemporal activation maps showing slow waves propagation is also demonstrated. The validation study found that flexible PCB electrode arrays are able to reliably record gastric slow wave activity with signal quality near that achieved by traditional epoxy resin-embedded silver electrode arrays. Flexible PCB electrode arrays provide a clinically viable alternative to previously published devices for the high-resolution mapping of GI slow wave activity. PCBs may be mass-produced at low cost, and are easily sterilized and potentially disposable, making them ideally suited to intra-operative human use. PMID:19224368

  4. High-resolution mapping of in vivo gastrointestinal slow wave activity using flexible printed circuit board electrodes: methodology and validation.

    PubMed

    Du, Peng; O'Grady, G; Egbuji, J U; Lammers, W J; Budgett, D; Nielsen, P; Windsor, J A; Pullan, A J; Cheng, L K

    2009-04-01

    High-resolution, multi-electrode mapping is providing valuable new insights into the origin, propagation, and abnormalities of gastrointestinal (GI) slow wave activity. Construction of high-resolution mapping arrays has previously been a costly and time-consuming endeavor, and existing arrays are not well suited for human research as they cannot be reliably and repeatedly sterilized. The design and fabrication of a new flexible printed circuit board (PCB) multi-electrode array that is suitable for GI mapping is presented, together with its in vivo validation in a porcine model. A modified methodology for characterizing slow waves and forming spatiotemporal activation maps showing slow waves propagation is also demonstrated. The validation study found that flexible PCB electrode arrays are able to reliably record gastric slow wave activity with signal quality near that achieved by traditional epoxy resin-embedded silver electrode arrays. Flexible PCB electrode arrays provide a clinically viable alternative to previously published devices for the high-resolution mapping of GI slow wave activity. PCBs may be mass-produced at low cost, and are easily sterilized and potentially disposable, making them ideally suited to intra-operative human use.

  5. Contact Resistance Characteristics of Improved Conductive Elastomer Contacts for Contaminated Printed Circuit Board in SO2 Environment

    NASA Astrophysics Data System (ADS)

    Tamai, Terutaka; Saitoh, Yasushi; Hattori, Yasuhiro; Ikeda, Hirosaka

    Characteristics of conductive elastomer that is composed of silicone rubber and dispersed carbon black particles show conductive and elastic properties in one simple material. This material has been widely applied to make-break contacts of panel switches and connectors of liquid crystal panels. However, since surface state of the contact is very soft, it is difficult to remove contaminant films of contaminated opposite side contact surface and to obtain low contact resistance owing to break the film. This is an important problem to be solved not only for the application of make-break switching contact but also static connector contacts. This study has been conducted to examine some complex structures of the elastomer which indicate removal characteristics for contaminant films and low contact resistance. As specimens, six different types of elastomer contacts composed of different type of dispersed materials as carbon and metal fibers, metal mesh, and plated surfaces were used. The contacts of opposite side were Au and Sn plated contact surface on a printed circuit board (PCB) which is usually used in the static connector and make-break contacts. In order to contaminate contact surfaces of PCB, the surfaces were subjected to exposure in an SO2 gas environment. The elastomeric contacts contained hard materials showed lower contact resistance than only dispersed carbon particles in the elastomer matrix for both contaminated PCB contact surfaces.

  6. Use of large pieces of printed circuit boards for bioleaching to avoid 'precipitate contamination problem' and to simplify overall metal recovery.

    PubMed

    Adhapure, N N; Dhakephalkar, P K; Dhakephalkar, A P; Tembhurkar, V R; Rajgure, A V; Deshmukh, A M

    2014-01-01

    Very recently bioleaching has been used for removing metals from electronic waste. Most of the research has been targeted to using pulverized PCBs for bioleaching where precipitate formed during bioleaching contaminates the pulverized PCB sample and making the overall metal recovery process more complicated. In addition to that, such mixing of pulverized sample with precipitate also creates problems for the final separation of non metallic fraction of PCB sample. In the present investigation we attempted the use of large pieces of printed circuit boards instead of pulverized sample for removal of metals. Use of large pieces of PCBs for bioleaching was restricted due to the chemical coating present on PCBs, the problem has been solved by chemical treatment of PCBs prior to bioleaching. In short,•Large pieces of PCB can be used for bioleaching instead of pulverized PCB sample.•Metallic portion on PCBs can be made accessible to bacteria with prior chemical treatment of PCBs.•Complete metal removal obtained on PCB pieces of size 4 cm × 2.5 cm with the exception of solder traces. The final metal free PCBs (non metallic) can be easily recycled and in this way the overall recycling process (metallic and non metallic part) of PCBs becomes simple.

  7. Development of two-step process for enhanced biorecovery of Cu-Zn-Ni from computer printed circuit boards.

    PubMed

    Shah, Monal B; Tipre, Devayani R; Purohit, Mamta S; Dave, Shailesh R

    2015-08-01

    Metal pollution due to the huge electronic waste (E-waste) accumulation is widespread across the globe. Extraction of copper, zinc and nickel from computer printed circuit boards (c-PCB) with a two-step bleaching process using ferric sulphate generated by Leptospirillum ferriphilum dominated consortium and the factors influencing the process were investigated in the present study. The studied factors with 10 g/L pulp density showed that pH 2.0 was optimum which resulted in 87.50-97.80% Cu-Zn-Ni extraction. Pre-treatment of PCB powder with acidified distilled water and NaCl solution showed 3.80-7.98% increase in metal extraction corresponding to 94.08% Cu, 99.80% Zn and 97.99% Ni extraction. Particle size of 75 μm for Cu and Zn while 1680 μm for Ni showed 2-folds increase in metal extraction, giving 97.35-99.80% Cu-Zn-Ni extraction in 2-6 days of reaction time. Whereas; 2.76-3.12 folds increase in Cu and Zn extraction was observed with the addition of 0.1% chelating agents. When the studies were carried out with high pulp density, ferric iron concentration of 16.57 g/L was found to be optimum for metal extraction from 75 g/L c-PCB and c-PCB addition in multiple installments resulted in 8.81-26.35% increase in metal extraction compared to single addition. The studied factors can be implemented for the scale-up aimed at faster recovery of multimetals from E-waste and thereby providing a secondary source of metal in an eco-friendly manner. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  8. Apparatus And Method Of Using Flexible Printed Circuit Board In Optical Transceiver Device

    DOEpatents

    Anderson, Gene R.; Armendariz, Marcelino G.; Bryan, Robert P.; Carson, Richard F.; Duckett, III, Edwin B.; McCormick, Frederick B.; Peterson, David W.; Peterson, Gary D.; Reysen, Bill H.

    2005-03-15

    This invention relates to a flexible printed circuit board that is used in connection with an optical transmitter, receiver or transceiver module. In one embodiment, the flexible printed circuit board has flexible metal layers in between flexible insulating layers, and the circuit board comprises: (1) a main body region orientated in a first direction having at least one electrical or optoelectronic device; (2) a plurality of electrical contact pads integrated into the main body region, where the electrical contact pads function to connect the flexible printed circuit board to an external environment; (3) a buckle region extending from one end of the main body region; and (4) a head region extending from one end of the buckle region, and where the head region is orientated so that it is at an angle relative to the direction of the main body region. The electrical contact pads may be ball grid arrays, solder balls or land-grid arrays, and they function to connect the circuit board to an external environment. A driver or amplifier chip may be adapted to the head region of the flexible printed circuit board. In another embodiment, a heat spreader passes along a surface of the head region of the flexible printed circuit board, and a window is formed in the head region of the flexible printed circuit board. Optoelectronic devices are adapted to the head spreader in such a manner that they are accessible through the window in the flexible printed circuit board.

  9. Evaluating waste printed circuit boards recycling: Opportunities and challenges, a mini review.

    PubMed

    Awasthi, Abhishek Kumar; Zlamparet, Gabriel Ionut; Zeng, Xianlai; Li, Jinhui

    2017-04-01

    Rapid generation of waste printed circuit boards has become a very serious issue worldwide. Numerous techniques have been developed in the last decade to resolve the pollution from waste printed circuit boards, and also recover valuable metals from the waste printed circuit boards stream on a large-scale. However, these techniques have their own certain specific drawbacks that need to be rectified properly. In this review article, these recycling technologies are evaluated based on a strength, weaknesses, opportunities and threats analysis. Furthermore, it is warranted that, the substantial research is required to improve the current technologies for waste printed circuit boards recycling in the outlook of large-scale applications.

  10. Impact of nonconductive powder on electrostatic separation for recycling crushed waste printed circuit board.

    PubMed

    Wu, Jiang; Qin, Yufei; Zhou, Quan; Xu, Zhenming

    2009-05-30

    The electrostatic separation is an effective and environmentally friendly method for recycling metals and nonmetals from crushed printed circuit board (PCB) wastes. However, it still confronts some problems brought by nonconductive powder (NP). Firstly, the NP is fine and liable to aggregate. This leads to an increase of middling products and loss of metals. Secondly, the stability of separation process is influenced by NP. Finally, some NPs accumulate on the surface of the corona and electrostatic electrodes during the process. These problems lead to an inefficient separation. In the present research, the impacts of NP on electrostatic separation are investigated. The experimental results show that: the separation is notably influenced when the NP content is more than 10%. With the increase of NP content, the middling products sharply increase from 1.4 g to 4.3g (increase 207.1%), while the conductive products decrease from 24.0 g to 19.1g (decrease 20.4%), and the separation process become more instable.

  11. Liberation characteristics after cryogenic modification and air table separation of discarded printed circuit boards.

    PubMed

    Zhou, Cuihong; Pan, Yongtai; Lu, Maxi; Yang, Changshun

    2016-07-05

    Liberating useful materials from printed circuit boards (PCBs) is challenging because PCBs are flexible and complex in terms of materials and components. In this study, the crushing of PCBs at low-temperature was investigated. The results indicated that when the temperature was decreased to approximately -20 °C, the strength of PCBs decreased and their brittleness increased, making them easier to crush. A double roll crusher was selected to crush the PCBs. The particle size distribution and power consumption were studied under different working conditions. The results showed that the particle size of most of the lumps was in the range 15×20-25×20 mm, and that power consumption was minimal when the frequency of the crusher was 40-50 Hz. A small shredder was used for cryogenic grinding, and it was found that its power consumption strongly depended on the cooling temperature. An orthogonal experiment was conducted, which revealed that a smaller cutter gap and higher rotational speed could achieve higher yield. Furthermore, the results indicated that the air table developed to liberate PCB materials could effectively separate 2.8-0.5mm grade materials. Overall, the results of this study provide an experimental foundation for more effectively recycling discarded PCBs. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Printed circuit board recycling: Physical processing and copper extraction by selective leaching.

    PubMed

    Silvas, Flávia P C; Correa, Mónica M Jiménez; Caldas, Marcos P K; de Moraes, Viviane T; Espinosa, Denise C R; Tenório, Jorge A S

    2015-12-01

    Global generation of waste electrical and electronic equipment (WEEE) is about 40 million tons per year. Constant increase in WEEE generation added to international legislations has improved the development of processes for materials recovery and sustainability of electrical and electronic industry. This paper describes a new hydrometallurgical route (leaching process) to recycle printed circuit boards (PCBs) from printers to recover copper. Methodology included PCBs characterization and a combined route of physical and hydrometallurgical processing. Magnetic separation, acid digestion and chemical analysis by ICP-OES were performed. On leaching process were used two stages: the first one in a sulfuric media and the second in an oxidant media. The results showed that the PCBs composition was 74.6 wt.% of non-magnetic material and 25.4 wt.% of magnetic one. The metallic fraction corresponded to 44.0 wt.%, the polymeric to 28.5 wt.% and the ceramic to 27.5 wt.%. The main metal was copper and its initial content was 32.5 wt.%. On sulfuric leaching 90 wt.% of Al, 40 wt.% of Zn and 8.6 wt.% of Sn were extracted, whereas on oxidant leaching tests the extraction percentage of Cu was 100 wt.%, of Zn 60 wt.% and of Al 10 wt.%. At the end of the hydrometallurgical processing was obtained 100% of copper extraction and the recovery factor was 98.46%, which corresponds to a 32 kg of Cu in 100 kg of PCB. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Prioritizing material recovery for end-of-life printed circuit boards.

    PubMed

    Wang, Xue; Gaustad, Gabrielle

    2012-10-01

    The increasing growth in generation of electronic waste (e-waste) motivates a variety of waste reduction research. Printed circuit boards (PCBs) are an important sub-set of the overall e-waste stream due to the high value of the materials contained within them and potential toxicity. This work explores several environmental and economic metrics for prioritizing the recovery of materials from end-of-life PCBs. A weighted sum model is used to investigate the trade-offs among economic value, energy saving potentials, and eco-toxicity. Results show that given equal weights for these three sustainability criteria gold has the highest recovery priority, followed by copper, palladium, aluminum, tin, lead, platinum, nickel, zinc, and silver. However, recovery priority will change significantly due to variation in the composition of PCBs, choice of ranking metrics, and weighting factors when scoring multiple metrics. These results can be used by waste management decision-makers to quantify the value and environmental savings potential for recycling technology development and infrastructure. They can also be extended by policy-makers to inform possible penalties for land-filling PCBs or exporting to the informal recycling sector. The importance of weighting factors when examining recovery trade-offs, particularly for policies regarding PCB collection and recycling are explored further. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Fast copper extraction from printed circuit boards using supercritical carbon dioxide.

    PubMed

    Calgaro, C O; Schlemmer, D F; da Silva, M D C R; Maziero, E V; Tanabe, E H; Bertuol, D A

    2015-11-01

    Technological development and intensive marketing support the growth in demand for electrical and electronic equipment (EEE), for which printed circuit boards (PCBs) are vital components. As these devices become obsolete after short periods, waste PCBs present a problem and require recycling. PCBs are composed of ceramics, polymers, and metals, particularly Cu, which is present in highest percentages. The aim of this study was to develop an innovative method to recover Cu from the PCBs of old mobile phones, obtaining faster reaction kinetics by means of leaching with supercritical CO2 and co-solvents. The PCBs from waste mobile phones were characterized, and evaluation was made of the reaction kinetics during leaching at atmospheric pressure and using supercritical CO2 with H2O2 and H2SO4 as co-solvents. The results showed that the PCBs contained 34.83 wt% of Cu. It was found that the supercritical extraction was 9 times faster, compared to atmospheric pressure extraction. After 20 min of supercritical leaching, approximately 90% of the Cu contained in the PCB was extracted using a 1:20 solid:liquid ratio and 20% of H2O2 and H2SO4 (2.5 M). These results demonstrate the efficiency of the process. Therefore the supercritical CO2 employment in the PCBs recycling is a promising alternative and the CO2 is environmentally acceptable and reusable.

  15. Integration of microelectronic chips in microfluidic systems on printed circuit board

    NASA Astrophysics Data System (ADS)

    Burdallo, I.; Jimenez-Jorquera, C.; Fernández-Sánchez, C.; Baldi, A.

    2012-10-01

    A new scheme for the integration of small semiconductor transducer chips with microfluidic structures on printed circuit board (PCB) is presented. The proposed approach is based on a packaging technique that yields a large and flat area with small and shallow (˜44 µm deep) openings over the chips. The photocurable encapsulant material used, based on a diacrylate bisphenol A polymer, enables irreversible bonding of polydimethylsiloxane microfluidic structures at moderate temperatures (80 °C). This integration scheme enables the insertion of transducer chips in microfluidic systems with a lower added volume than previous schemes. Leakage tests have shown that the bonded structures withstand more than 360 kPa of pressure. A prototype microfluidic system with two detection chips, including one inter-digitated electrode (IDE) chip for conductivity and one ion selective field effect transistor (ISFET) chip for pH, has been implemented and characterized. Good electrical insulation of the chip contacts and silicon edge surfaces from the solution in the microchannels has been achieved. This integration procedure opens the door to the low-cost fabrication of complex analytical microsystems that combine the extraordinary potential of both the microfluidics and silicon microtechnology fields.

  16. Simultaneous detection of lactate and glucose by integrated printed circuit board based array sensing chip.

    PubMed

    Li, Xuelian; Zang, Jianfeng; Liu, Yingshuai; Lu, Zhisong; Li, Qing; Li, Chang Ming

    2013-04-10

    An integrated printed circuit board (PCB) based array sensing chip was developed to simultaneously detect lactate and glucose in mouse serum. The novelty of the chip relies on a concept demonstration of inexpensive high-throughput electronic biochip, a chip design for high signal to noise ratio and high sensitivity by construction of positively charged chitosan/redox polymer Polyvinylimidazole-Os (PVI-Os)/carbon nanotube (CNT) composite sensing platform, in which the positively charged chitosan/PVI-Os is mediator and electrostatically immobilizes the negatively charged enzyme, while CNTs function as an essential cross-linker to network PVI-Os and chitosan due to its negative charged nature. Additional electrodes on the chip with the same sensing layer but without enzymes were prepared to correct the interferences for high specificity. Low detection limits of 0.6 μM and 5 μM were achieved for lactate and glucose, respectively. This work could be extended to inexpensive array sensing chips with high sensitivity, good specificity and high reproducibility for various sensor applications.

  17. Ion chromatography in the manufacture of multilayer circuit boards

    SciTech Connect

    Smith, R.E.

    1990-09-01

    Ion chromatography (IC) has proven useful in analyzing chemical solutions used in the manufacture of multilayer circuit boards. The manufacturing process is described briefly and previously published IC methods are reviewed. Then, methods are described for determining chlorate and chlorite in a brown oxide solution; salicylic acid in an epoxy cure agent; formate, sulfate, and tartrate in an electroless copper bath; anionic detergents in a tin-lead brightener and in a cleaning solution; and aqueous photoresist and nonionic brightener in a tin-lead bath. Anion exchange, reverse phase HPLC on a poly(styrene/divinylbenzene), PS/DVB, column and two-dimensional liquid chromatography also are described. Chemically suppressed conductivity and photometric detection are used. 13 refs., 10 figs., 1 tab.

  18. Printed-circuit-board manufacturer maximizes recycling opportunities

    SciTech Connect

    Edelstein, P. )

    1993-02-01

    A major New England printed-circuit-board manufacturer has avoided land disposal of several metallic wastes for more than 15 years by recycling them offsite. For example, the company uses ammoniacal etchant to etch copper. Waste generated by this process is used by an offsite recycler to produce copper compounds for pressure-treated lumber and for use as a catalyst. Sodium persulfate and peroxide-sulfuric micro-etchants are used at the facility, generating a crude copper sulfate solution, and copper sulfate also is the basis for the company's electroplating process. Wastes from all of these processes are used by an offsite recycler to produce copper compounds that are sold for use in wood treatment and as mining reagents. Finally, metal hydroxide sludge generated by the company's wastewater treatment system contains substantial amounts of copper, which is sent for refining at a copper smelter.

  19. USB-driven microfluidic chips on printed circuit boards.

    PubMed

    Li, Jiang; Wang, Yixuan; Dong, Enkai; Chen, Haosheng

    2014-03-07

    A technology is presented to fabricate a microfluidic chip in which the microchannels and the microelectrodes of sensors are integrated directly into the copper sheet on a printed circuit board. Then, we demonstrate an application of the generation of oil-in-water and water-in-oil emulsion droplets on this microfluidic chip driven by a USB interface, and the droplet size is detected by the microelectrodes on the downstream microchannel. The integration of the microfluidic chip is improved by the direct connection of the channels to the microelectrodes of the driving unit and of the sensors on the same substrate, and it is a promising way to integrate microfluidics into a more complex micro electrical-mechanical system (MEMS).

  20. Ultrasonic decontamination in perfluorinated liquids of radioactive circuit boards

    SciTech Connect

    Yam, C.S.; Harling, O.K.; Kaiser, R.

    1994-12-31

    A laboratory-scale ultrasonic decontamination system has been developed to demonstrate the application of Entropic System`s enhanced particle removal process to the radioactive decontamination of electronic circuit boards. The process uses inert perfluorinated liquids as the working media; the liquids have zero ozone depletion potential, are nontoxic, non-flammable, and are generally recognized as nonhazardous materials. The parts to be cleaned are first sonicated with a dilute solution of a high-molecular-weight fluorocarbon surfactant in an inert perfluorinated liquid. The combination of ultrasonic agitation and liquid flow promotes the detachment of the particles from the surface of the part being cleaned, their transfer from the boundary layer into the bulk liquid, and their removal from the cleaning environment, thereby reducing the probability of particle redeposition. After the cleaning process, the parts are rinsed with the pure perfluorinated liquid to remove residual surfactant. The parts are recovered after the perfluorinated liquid is evaporated into air.

  1. Ion chromatography in the manufacture of multilayer circuit boards

    NASA Astrophysics Data System (ADS)

    Smith, Robert E.

    1990-09-01

    Ion chromatography (IC) has proven useful in analyzing chemical solutions used in the manufacture of multilayer circuit boards. The manufacturing process is described briefly and previously published IC methods are reviewed. Then, methods are described for determining chlorate and chlorite in a brown oxide solution; salicylic acid in an epoxy cure agent; formate, sulfate, and tartrate in an electroless copper bath; anionic detergents in a tin-lead brightener and in a cleaning solution; and aqueous photoresist and nonionic brightener in a tin-lead bath. Anion exchange, reverse phase HPLC on a poly(styrene/divinylbenzene), PS/DVB, column and 2-D liquid chromatography also are described. Chemically suppressed conductivity and photometric detection are used.

  2. Tailored benzoxazines as novel resin systems for printed circuit boards in high temperature e-mobility applications

    SciTech Connect

    Troeger, K. Darka, R. Khanpour Neumeyer, T. Altstaedt, V.

    2014-05-15

    This study focuses on the development of Bisphenol-F-benzoxazine resins blended with different ratios of a trifunctional epoxy resin suitable as matrix for substrates for high temperature printed circuit board (HT-PCB) applications. With the benzoxazine blends glass transition temperatures of more than 190 °C could be achieved in combination with a coefficient of thermal expansion in thickness direction (z-CTE) of less than 60 ppm/K without adding any fillers. This shows the high potential of the benzoxazine-epoxy blend systems as substrate materials for HT-PCBs. To understand the thermal behavior of the different formulations, the apparent crosslink density was calculated based on data from Dynamic Mechanical Analysis. Laminates in laboratory scale were prepared and characterized to demonstrate the transformation of the neat resin properties into real electronic substrate properties. The produced laminates exhibit a z-CTE below 40 ppm/K.

  3. The cooling of printed circuit board mounted components using copper ladder heat conduction to a cold wall

    NASA Astrophysics Data System (ADS)

    Dale, I. C.

    1982-09-01

    A series of experimental tests, designed to investigate the cooling of printed circuit board (PCB) mounted dual-in-line (DIL) components within an avionic box using the copper ladder/cold wall technique is described. Areas of investigation include avionic box orientation, side wall conduction, top plate finning, mixed air-wash, avionic power reduction, cooling air temperature reduction, cooling air mass flow rate reduction, cold wall heat pick-up and avionic box insulation. Results were obtained from thermocouple temperature measurements. The use of an aluminum alloy interplate to cool two adjacent PCBs is discussed. Results in graphic form are included together with a list of conclusions on the effects of all the major parameters considered.

  4. Aluminum heat sink enables power transistors to be mounted integrally with printed circuit board

    NASA Technical Reports Server (NTRS)

    Seaward, R. C.

    1967-01-01

    Power transistor is provided with an integral flat plate aluminum heat sink which mounts directly on a printed circuit board containing associated circuitry. Standoff spacers are used to attach the heat sink to the printed circuit board containing the remainder of the circuitry.

  5. Anisotropic viscoelastic shell modeling technique of copper patterns/photoimageable solder resist composite for warpage simulation of multi-layer printed circuit boards

    NASA Astrophysics Data System (ADS)

    Kim, Do-Hyoung; Joo, Sung-Jun; Kwak, Dong-Ok; Kim, Hak-Sung

    2015-10-01

    In this study, the warpage simulation of a multi-layer printed circuit board (PCB) was performed as a function of various copper (Cu) patterns/photoimageable solder resist (PSR) composite patterns and their anisotropic viscoelastic properties. The thermo-mechanical properties of Cu/PSR patterns were obtained from finite element analysis (virtual test) and homogenized with anisotropic composite shell models that considered the viscoelastic properties. The multi-layer PCB model was simplified based on the unit Cu/PSR patterns and the warpage simulation during the reflow process was performed by using ABAQUS combined with a user-defined subroutine. From these results, it was demonstrated that the proposed anisotropic viscoelastic composite shell simulation technique can be successfully used to predict warpage of multi-layer PCBs during the reflow process.

  6. A Circuit Board Using a Sheet of Thick Paper and Aluminium Tape

    ERIC Educational Resources Information Center

    Kamata, Masahiro; Honda, Motoshi

    2003-01-01

    We have developed a circuit board using materials that are inexpensive and familiar to elementary school students. Most of the responses from students who made this board were relatively positive and we observed them enjoy making the boards at a Science Festival in Japan and in elementary school. As an application, we also developed a tiny torch…

  7. A Circuit Board Using a Sheet of Thick Paper and Aluminium Tape

    ERIC Educational Resources Information Center

    Kamata, Masahiro; Honda, Motoshi

    2003-01-01

    We have developed a circuit board using materials that are inexpensive and familiar to elementary school students. Most of the responses from students who made this board were relatively positive and we observed them enjoy making the boards at a Science Festival in Japan and in elementary school. As an application, we also developed a tiny torch…

  8. Ultra-sensitive electrical immunoassay biosensors using nanotextured zinc oxide thin films on printed circuit board platforms.

    PubMed

    Jacobs, Michael; Muthukumar, Sriram; Panneer Selvam, Anjan; Engel Craven, Jon; Prasad, Shalini

    2014-05-15

    This study demonstrates the development of nanotextured zinc oxide (ZnO) thin films sputter deposited on printed circuit boards (PCB) to enhance the capability in detecting low concentrations of the protein troponin-T. The presence of this particular biomarker in the bloodstream is a direct indicator of current and/or future risk of various forms of cardiovascular diseases. Electrical transduction through impedance spectroscopy was used to detect troponin-T functionalized immunoassays on nanotextured ZnO surfaces. Calibration of the immunoassay was performed by measuring the impedance changes resulting from the binding of increasing concentrations of troponin-T to the immobilized antibodies on the ZnO surface in (i) phosphate buffered saline (PBS) and (ii) human serum. The limit of detection achieved using this platform was 10 fg/mL and 100 fg/mL in PBS and human serum, respectively. Enhanced detection of troponin-T was found to correlate to the oxygen vacancies in the ZnO thin film. PCB was chosen as the substrate for ease of integration with microelectronic device manufacturing. © 2013 Elsevier B.V. All rights reserved.

  9. Levitation and movement of human tumor cells using a printed circuit board device based on software-controlled dielectrophoresis.

    PubMed

    Altomare, L; Borgatti, M; Medoro, G; Manaresi, N; Tartagni, M; Guerrieri, R; Gambari, R

    2003-05-20

    In this study we describe an original, efficient, and innovative printed circuit board (PCB) device able to generate dielectrophoresis-based, software-controlled cages that can be moved to any place inside a microchamber. Depending on their dielectrophoretic properties, eukaryotic cells can be "entrapped" in cages and moved under software control. The main conclusion gathered from the experimental data reported is that the PCB device based on dielectrophoresis permits levitation and movement of different tumor cells at different dielectrophoresis conditions. The results presented herein are therefore the basis for experiments aimed at forced interactions or separation of eukaryotic cells using "lab-on-a-chip." In fact, because many cages can be controlled at the same time, and two or more cages can be forced to share the same or a different location, it is possible, in principle, either to bring in contact cells of a differing histotype or to separate them. Copyright 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 474-479, 2003.

  10. Technology development of RF MEMS switches on printed circuit boards

    NASA Astrophysics Data System (ADS)

    Chang, Hung-Pin

    Today, some engineers have shifted their focus on the micro-electro-mechanical system (MEMS) to pursue better technological advancements. Recent development in RF MEMS technologies have lead to superior switch characteristics, i.e., very low insertion loss, very low power requirements, and high isolation comparing to the conventional semiconductor devices. This success has promised the potential of MEMS to revolutionize RF and microwave system implementation for the next generation of communication applications. However, RF MEMS switches integrated monolithically with various RF functional components on the same substrate to create multifunctional and reconfigurable complete communication systems remains to be a challenge research topic due to the concerns of the high cost of packaging process and the high cost of RF matching requirements in module board implementation. Furthermore, the fabrication of most RF MEMS switches requires thickness control and surface planarization of wide metal lines prior to deposition of a metal membrane bridge, which poses a major challenge to manufacturability. To ease the fabrication of RF MEMS switches and to facilitate their integration with other RF components such as antennas, phase delay lines, tunable filters, it is imperative to develop a manufacturable RF MEMS switch technology on a common substrate housing all essential RF components. Development of a novel RF MEMS technology to build a RF MEMS switch and provide a system-level packaging on microwave laminated printed circuit boards (PCBs) are proposed in this dissertation. Two key processes, high-density inductively coupled plasma chemical vapor deposition (HDICP CVD) for low temperature dielectric deposition, and compressive molding planarization (COMP) for the temporary sacrificial polymer planarization have been developed for fabricating RF MEMS switches on PCBs. Several membrane-type capacitive switches have been fabricated showing excellent RF performance and dynamic

  11. Polymers for electrical connections in printed circuit boards

    NASA Astrophysics Data System (ADS)

    Kisiel, Ryszard

    2006-10-01

    It is becoming more and more difficult for the conventional PCBs with mechanically drilled vias and plated through holes to meet the current packaging density requirements. To overcome these challenges, new manufacturing schemes for high density and high performance multilayer PCBs have been developed. The polymer materials play important role in finding the cheap solution. Polymer materials are used to make reliable vertical interconnects in substrates made by SBU (Sequential build-up) processes. The SBU technology with conductive paste filled microvias can achieve a connection density of up to 100 pads/cm2 while the conventional PTHs can reach only 20 pads/cm2. The polymer base materials can be used to replace solders in PCB assembly. The exploitation data obtained from own research, and connected with applying adhesives in inner connections into PCB as well as connected with component assembly on PCB were given.

  12. Using multiple sensors for printed circuit board insertion

    NASA Technical Reports Server (NTRS)

    Sood, Deepak; Repko, Michael C.; Kelley, Robert B.

    1989-01-01

    As more and more activities are performed in space, there will be a greater demand placed on the information handling capacity of people who are to direct and accomplish these tasks. A promising alternative to full-time human involvement is the use of semi-autonomous, intelligent robot systems. To automate tasks such as assembly, disassembly, repair and maintenance, the issues presented by environmental uncertainties need to be addressed. These uncertainties are introduced by variations in the computed position of the robot at different locations in its work envelope, variations in part positioning, and tolerances of part dimensions. As a result, the robot system may not be able to accomplish the desired task without the help of sensor feedback. Measurements on the environment allow real time corrections to be made to the process. A design and implementation of an intelligent robot system which inserts printed circuit boards into a card cage are presented. Intelligent behavior is accomplished by coupling the task execution sequence with information derived from three different sensors: an overhead three-dimensional vision system, a fingertip infrared sensor, and a six degree of freedom wrist-mounted force/torque sensor.

  13. Materials recovery from waste printed circuit boards by supercritical methanol.

    PubMed

    Xiu, Fu-Rong; Zhang, Fu-Shen

    2010-06-15

    The recovery of valuable materials from waste printed circuit boards (PCBs) is quite difficult due to the heterogeneous mix of polymer materials, multiple kinds of metals and glass fiber. A feasibility study was conducted using supercritical methanol (SCM) to simultaneously recover polymers and metals from waste PCBs. The study focused on the characteristics of both oils and solid products obtained from the SCM-treated waste PCBs. The operation conditions were temperature range of 300-420 degrees C, treatment time between 30 and 120 min and solid-to-liquid ratio (S/L) of 1:10-1:30 (g/mL) so as to understand the products and depolymerization mechanisms of waste PCBs in SCM. GC-MS results revealed that the oils mainly contained phenol and its methylated derivatives, and the methylated derivatives increased with the increase of reaction temperature. The methylated reaction occurred mainly above 400 degrees C. The liquid products also contained a significant number of phosphated fire retardant additives such as triphenyl phosphate, which decreased significantly with the increase of reaction temperature. The solid product mainly consisted of Cu, Fe, Sn, Pb and Zn, as well as lower concentrations of precious metals such as Ag and Au.

  14. Hydrometallurgical Recovery of Metals from Large Printed Circuit Board Pieces

    PubMed Central

    Jadhav, U.; Hocheng, H.

    2015-01-01

    The recovery of precious metals from waste printed circuit boards (PCBs) is an effective recycling process. This paper presents a promising hydrometallurgical process to recover precious metals from waste PCBs. To simplify the metal leaching process, large pieces of PCBs were used instead of a pulverized sample. The chemical coating present on the PCBs was removed by sodium hydroxide (NaOH) treatment prior to the hydrometallurgical treatment. Among the leaching reagents examined, hydrochloric acid (HCl) showed great potential for the recovery of metals. The HCl-mediated leaching of waste PCBs was investigated over a range of conditions. Increasing the acid concentration decreased the time required for complete metal recovery. The shaking speed showed a pronounced positive effect on metal recovery, but the temperature showed an insignificant effect. The results showed that 1 M HCl recovered all of the metals from 4 cm × 4 cm PCBs at room temperature and 150 rpm shaking speed in 22 h. PMID:26415827

  15. Examining the evolution of metals utilized in printed circuit boards.

    PubMed

    Adie, Gilbert Umaye; Sun, Lingyu; Zeng, Xianlai; Zheng, Lixia; Osibanjo, Oladele; Li, Jinhui

    2017-07-01

    Management of waste electrical and electronic equipment (WEEE) has recently attracted worldwide attention because of high metal concentrations in them. Evolution of toxic and precious metals utilized in WEEE can not only reflect the adventure of eco-design, but can also guide the final recycling option. Pb, As, Cu, Au, Sn and Ag were determined in 10 composite samples of printed circuit boards of cathode ray tube televisions (TV-PCBs) that were produced between 1980 and 2005. The obtained results indicated that average metal concentrations in all TV-PCBs were - Cu: 10.6 ± 4.1%, Sn: 4.21 ± 0.90%, Pb: 3.15 ± 0.54%, Ag: 0.0215 ± 0.0068%, Au: 0.0068 ± 0.0049% and As: 0.0007 ± 0.0004%. No remarkable difference was found in compositions of Pb and Sn over the years, suggesting that there were no major modifications of Sn/Pb solder used in joining the circuitry system. The average composition of Cu fluctuated between 5.10% in 1980 and 12.8% in the mid-1990s and decreased afterwards. The decreases in Ag and Cu compositions could possibly be associated with thinner layers of these metals in newer model products.

  16. Hydrometallurgical Recovery of Metals from Large Printed Circuit Board Pieces

    NASA Astrophysics Data System (ADS)

    Jadhav, U.; Hocheng, H.

    2015-09-01

    The recovery of precious metals from waste printed circuit boards (PCBs) is an effective recycling process. This paper presents a promising hydrometallurgical process to recover precious metals from waste PCBs. To simplify the metal leaching process, large pieces of PCBs were used instead of a pulverized sample. The chemical coating present on the PCBs was removed by sodium hydroxide (NaOH) treatment prior to the hydrometallurgical treatment. Among the leaching reagents examined, hydrochloric acid (HCl) showed great potential for the recovery of metals. The HCl-mediated leaching of waste PCBs was investigated over a range of conditions. Increasing the acid concentration decreased the time required for complete metal recovery. The shaking speed showed a pronounced positive effect on metal recovery, but the temperature showed an insignificant effect. The results showed that 1 M HCl recovered all of the metals from 4 cm × 4 cm PCBs at room temperature and 150 rpm shaking speed in 22 h.

  17. Application of the model of the printed circuit board with regard to the topology of external conductive layers for calculation of the thermal conditions of the printed circuit board

    NASA Astrophysics Data System (ADS)

    Rybakov, I. M.; Goryachev, N. V.; Kochegarov, I. I.; Grishko, A. K.; Brostilov, S. A.; Yurkov, N. K.

    2017-01-01

    The paper proves the necessity of taking into account external conductive layers of the printed circuit board with the thermal physical designing radio-electronic means. For example, a single printed circuit board shows the level of influence of the external conductive layer on the thermal conditions of the printed circuit board. It proved the influence of Joule heat in the thermal conditions of a single conductor. Developed geometrical and thermal printed circuit board models take into account the topological layer and can improve the accuracy of determining the thermal conditions of the printed circuit board.

  18. Prioritizing material recovery for end-of-life printed circuit boards

    SciTech Connect

    Wang Xue; Gaustad, Gabrielle

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Material recovery driven by composition, choice of ranking, and weighting. Black-Right-Pointing-Pointer Economic potential for new recycling technologies quantified for several metrics. Black-Right-Pointing-Pointer Indicators developed for materials incurring high eco-toxicity costs. Black-Right-Pointing-Pointer Methodology useful for a variety of stakeholders, particularly policy-makers. - Abstract: The increasing growth in generation of electronic waste (e-waste) motivates a variety of waste reduction research. Printed circuit boards (PCBs) are an important sub-set of the overall e-waste stream due to the high value of the materials contained within them and potential toxicity. This work explores several environmental and economic metrics for prioritizing the recovery of materials from end-of-life PCBs. A weighted sum model is used to investigate the trade-offs among economic value, energy saving potentials, and eco-toxicity. Results show that given equal weights for these three sustainability criteria gold has the highest recovery priority, followed by copper, palladium, aluminum, tin, lead, platinum, nickel, zinc, and silver. However, recovery priority will change significantly due to variation in the composition of PCBs, choice of ranking metrics, and weighting factors when scoring multiple metrics. These results can be used by waste management decision-makers to quantify the value and environmental savings potential for recycling technology development and infrastructure. They can also be extended by policy-makers to inform possible penalties for land-filling PCBs or exporting to the informal recycling sector. The importance of weighting factors when examining recovery trade-offs, particularly for policies regarding PCB collection and recycling are explored further.

  19. Recovery of metallic concentrations from waste printed circuit boards via reverse floatation.

    PubMed

    He, Jingfeng; Duan, Chenlong

    2017-02-01

    Efficient disposal of waste printed circuit boards (PCBs) is favorable toward recovering valuable components and reducing pollution. Reverse floatation was used to recover metallic concentrations from waste PCBs. Basic properties and mineralogical characteristics of raw PCBs were tested and analyzed. Results indicated that the grade of metallic concentrations declined as the size fraction of PCBs decreased. The major metallic elements found in PCBs were Cu, Pb, and Sn, as well as trace elements were also found in fine PCB particles. Kerosene and terpenic oil were used as the collector and frother in the floatation experiments. The effects of various operational factors, including the feeding concentration, aeration rate, and agitation speed of floatation machine, on the floatation performance of -0.25mm PCBs were experimentally studied to determine optimal range. The floatation results suggested that the yield of sinks and grade of metallic concentrations diminished significantly with the decrease of size fraction of PCBs. The maximum yields of sinks and highest grades of metallic concentrations were 48.72% and 16.86%, 47.96% and 14.61%, 44.36% and 8.81%, with the optimum recoveries of metallic concentrations of 94.69%, 90.06%, and 75.96% for size fractions of 0.125-0.25mm, 0.074-0.125mm, and -0.074mm PCBs, respectively. The recovery efficiency of metallic concentrations declined as the size fraction decreased. The efficient overall recovery performance of metallic concentrations from waste PCBs was obtained via reverse floatation. This study provides an alternative approach for disposing waste PCBs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Liquid oil and residual characteristics of printed circuit board recycle by pyrolysis.

    PubMed

    Lin, Kuo-Hsiung; Chiang, Hung-Lung

    2014-04-30

    Non-metal fractions of waste printed circuit boards (PCBs) were thermally treated (200-500°C) under nitrogen atmosphere. Carbon, hydrogen, and nitrogen were determined by elemental analyzer, bromine by instrumental neutron activation analysis (INAA), phosphorus by energy dispersive X-ray spectrometer (EDX), and 29 trace elements by inductively coupled plasma atomic emission spectrometer (ICP-AES) and mass spectrometry (ICP-MS) for raw material and pyrolysis residues. Organic compositions of liquid oil were identified by GC (gas chromatography)-MS, trace element composition by ICP system, and 12 water-soluble ions by IC (ionic chromatography). Elemental content of carbon was >450 mg/g, oxygen 300 mg/g, bromine and hydrogen 60 mg/g, nitrogen 30 mg/g, and phosphorus 28 mg/g. Sulfur was trace in PCBs. Copper content was 25-28 mg/g, iron 1.3-1.7 mg/g, tin 0.8-1.0mg/g and magnesium 0.4-1.0mg/g; those were the main metals in the raw materials and pyrolytic residues. In the liquid products, carbon content was 68-73%, hydrogen was 10-14%, nitrogen was 4-5%, and sulfur was less than 0.05% at pyrolysis temperatures from 300 to 500°C. Phenol, 3-bromophenol, 2-methylphenol and 4-propan-2-ylphenol were major species in liquid products, accounting for >50% of analyzed organic species. Bromides, ammonium and phosphate were the main species in water sorption samples for PCB pyrolysis exhaust.

  1. Evaluation of gold and silver leaching from printed circuit board of cellphones.

    PubMed

    Petter, P M H; Veit, H M; Bernardes, A M

    2014-02-01

    Electronic waste has been increasing proportionally with the technology. So, nowadays, it is necessary to consider the useful life, recycling, and final disposal of these equipment. Metals, such as Au, Ag, Cu, Sn and Ni can be found in the printed circuit boards (PCB). According to this, the aims of this work is to characterize the PCBs of mobile phones with aqua regia; obtaining "reference" values of leaching, to gold and silver, with cyanide and nitric acid, respectively; and study the process of leaching of these metals in alternative leaching with sodium thiosulfate and ammonium thiosulfate. The metals were characterized by digesting the sample with aqua regia for 1 and 2h at 60°C and 80°C. The leaching of Au with a commercial reagent (cyanide) and the Ag with HNO3were made. The leaching of Au and Ag with alternative reagents: Na2S2O3, and (NH4)2S2O3 in 0.1M concentration with the addition of CuSO4, NH4OH, and H2O2, was also studied. The results show that the digestion with aqua regia was efficient to characterize the metals present in the PCBs of mobile phones. However, the best method to solubilize silver was by digesting the sample with nitric acid. The leaching process using sodium thiosulfate was more efficient when an additional concentration of 0.015 and 0.030 M of the CuSO4 was added. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Alternatives Assessment: Partnership to Evaluate Flame Retardants in Printed Circuit Boards

    EPA Pesticide Factsheets

    The partnership project on flame retardants in printed circuit boards seeks to improve understanding of the environmental and human health impacts of new and current materials that can be used to meet fire safety standards

  3. TSCA Chemical Data Reporting Fact Sheet: Byproducts Reporting for the Printed Circuit Board Industry

    EPA Pesticide Factsheets

    This fact sheet provides information on existing Chemical Data Reporting (CDR) rule requirements related to byproducts reporting by persons who manufacture printed circuit boards and may be subject to CDR.

  4. Laser structuring of ultra-fine circuit lines in printed circuit boards: Laser structuring, neodymium-doped yttrium aluminium garnet laser, fine circuit lines

    NASA Astrophysics Data System (ADS)

    Zhang, Bin

    Laser structuring technique emerged in recent years for the need of fabricating fine circuit lines and spaces in printed circuit board. Most of the previous work only introduced laser structuring as a new method in the fabrication of fine circuit lines and mentioned that the width of circuit line can be reduced under 50 pin or helox with this technique. Laser structuring technique will have a prosperous future only when the relationship between process parameters and fabrication results are deeply understood. This study focuses on the control, prediction and optimization of circuit geometry by studying relations between the process parameters and fabrication results in laser structuring technology. The effects of laser parameters (Frequency-tripled Nd:YAG laser) on the geometry of circuits were carried out by experiments and analyzed by mathematical method. The geometry of circuit space can efficiently be controlled by investigating the main factors that influence the characteristic parameters of circuit space with Taguchi methodology. ANN was firstly used in the study of laser structuring technique. With ANN models, the optimization of process parameters in laser writing step can be realized and the 2-D cross-sectional profile of circuit space can be calculated with the combination of ANN model and mathematical method. At last, the final circuit lines and circuit spaces fabricated were tested using the quality and reliability tests---electrical open/short test, peel test and surface insulation resistance test (SIR test). The minimum widths of circuit lines and circuit spaces with good quality and reliability fabricated by laser structuring were 25 mum and 45 mum respectively. The project is significant for both applied and academic fields. This study contributes to the understanding of the laser structuring technology and is of benefit in the fabrication of very fine line circuits in advanced printed circuit board industry.

  5. Dielectric nanocomposites for high performance embedded capacitors in organic printed circuit boards

    NASA Astrophysics Data System (ADS)

    Xu, Jianwen

    Conventionally discrete passive components like capacitors, resistors, and inductors are surface-mounted on top of the printed circuit boards (PCBs). To match the ever increasing demands of miniaturization, cost reduction, and high performance in microelectronic industry, a promising approach is to integrate passive components into the board during PCB manufacture. Because they are embedded inside multilayer PCBs, such components are called embedded passives. This work focuses on the materials design, development and processing of polymer-based dielectric nanocomposites for embedded capacitor applications. The methodology of this approach is to combine the advantages of the polymer and the filler to satisfy the electric, dielectric, mechanical, fabrication, and reliability requirements for embedded capacitors. Restrained by poor adhesion and poor thermal stress reliability at high filler loadings, currently polymer-ceramic composites can only achieve a dielectric constant of less than 50. In order to increase the dielectric constant to above 50, effects of high-kappa polymer matrix, bimodal fillers, and dispersing agent are systematically investigated. Surface functionalization of nanofiller particles and modification of epoxy matrix with a secondary rubberized epoxy to form sea-island structure are proposed to enhance the dielectric constant, adhesion and high-temperature thermal stress reliability of high-kappa composites. To obtain photodefinable high-kappa composites, fundamental understanding of the photopolymerization of the novel epoxy-ceramic composite photoresist is addressed. While the properties of high-kappa composites largely depend on the polymer matrix, the fillers can also drastically affect the material properties. Carbon black- and carbon nanotubes-filled ultrahigh-kappa polymer composites are investigated as the candidate materials for embedded capacitors. Dielectric composites based on percolation typically show a high dielectric constant, and a

  6. Two-photon absorption for the realization of optical waveguides on printed circuit boards

    NASA Astrophysics Data System (ADS)

    Langer, Gregor; Riester, Markus

    2007-02-01

    The integration of optical interconnections in printed circuit boards (PCBs) is an emerging field that arouses rapidly growing interest worldwide. At present the key issue is to identify a technical concept, which allows for the realization of optical interconnections that are compatible to existing PCB manufacturing processes. Above all, the material in which the optical interconnections are embedded has to withstand increased temperatures and lamination pressures as well as various wet chemistry processes. AT&S uses so-called two-photon absorption (TPA) laser structuring - a rather new and innovative technology - to realize optical circuits in a special polymer layer. In this case a near infrared laser is applied working in the femto-second regime. The high photon density that can be reached in the laser's focus results in a modification of the optical polymer, which is usually photosensitive in the UV-spectrum of light only. In our particular case, the refractive index of the optical polymer is increased. Choosing the right laser intensity and focus propagation speed one achieves a waveguide well embedded within the polymer layer, which has not been affected by the laser. In contrast to one-photon absorption, which only allows a two dimensional respectively lateral modification of a polymer, this technology allows a modification within the volume resulting in 3D-microstructures inside the polymer layer. Apart from the possibility to realize structures in three dimensions, this TPA-technique has additional advantages. First of all, it allows one step fabrication, which reduces costs and production time compared to etching procedures or conventional UV lithography processes. Moreover, this technique allows varying the waveguide's cross section geometry and diameter simply varying size and form of the structuring laser focus. Whereas the realization of optical waveguides is not challenging anymore the coupling of waveguides with optoelectronic components is rather

  7. Problem-Solving at a Circuit-Board Assembly Machine: A Microanalysis.

    ERIC Educational Resources Information Center

    Kleifgen, Jo Anne; Frenz-Belken, Patricia

    A study described machine operators' problem-solving actions at a computerized circuit-board assembly machine in a small manufacturing plant located on the West Coast. Participants were a machine operator and his supervisor, both from Vietnam, who were building large prototype boards for a major computer corporation. Over a 6.5 minute interval,…

  8. Fluid Power Multi-actuator Circuit Board with Microcomputer Control Option.

    ERIC Educational Resources Information Center

    McKechnie, R. E.; Vickers, G. W.

    1981-01-01

    Describes a portable fluid power engineering laboratory and class demonstration apparatus designed to enable students to design, build, and test multi-actuator circuits. Features a variety of standard pneumatic values and actuators fitted with quick disconnect couplings. Discusses sequencing circuit boards, microcomputer control, cost, and…

  9. Fluid Power Multi-actuator Circuit Board with Microcomputer Control Option.

    ERIC Educational Resources Information Center

    McKechnie, R. E.; Vickers, G. W.

    1981-01-01

    Describes a portable fluid power engineering laboratory and class demonstration apparatus designed to enable students to design, build, and test multi-actuator circuits. Features a variety of standard pneumatic values and actuators fitted with quick disconnect couplings. Discusses sequencing circuit boards, microcomputer control, cost, and…

  10. Ultra-Small Reader/Writer with Multiple Contactless Interfaces on a Flexible Circuit Board

    NASA Astrophysics Data System (ADS)

    Yamamoto, Hideaki; Ikeda, Minoru; Hosoda, Yasuhiro

    In order to incorporate the reader/writers (RWs) into mobile electronic devices, miniaturization and flexibility are required. To meet these requirements, we fabricate an ultra-small RW with multiple contactless interfaces by mounting main unit circuits inside the antenna coil and using flexible multi-layer circuit board.

  11. Printed circuit board impedance matching step for microwave (millimeter wave) devices

    DOEpatents

    Pao, Hsueh-Yuan; Aguirre, Jerardo; Sargis, Paul

    2013-10-01

    An impedance matching ground plane step, in conjunction with a quarter wave transformer section, in a printed circuit board provides a broadband microwave matching transition from board connectors or other elements that require thin substrates to thick substrate (>quarter wavelength) broadband microwave (millimeter wave) devices. A method of constructing microwave and other high frequency electrical circuits on a substrate of uniform thickness, where the circuit is formed of a plurality of interconnected elements of different impedances that individually require substrates of different thicknesses, by providing a substrate of uniform thickness that is a composite or multilayered substrate; and forming a pattern of intermediate ground planes or impedance matching steps interconnected by vias located under various parts of the circuit where components of different impedances are located so that each part of the circuit has a ground plane substrate thickness that is optimum while the entire circuit is formed on a substrate of uniform thickness.

  12. Sensor fusion of phase measuring profilometry and stereo vision for three-dimensional inspection of electronic components assembled on printed circuit boards.

    PubMed

    Hong, Deokhwa; Lee, Hyunki; Kim, Min Young; Cho, Hyungsuck; Moon, Jeon Il

    2009-07-20

    Automatic optical inspection (AOI) for printed circuit board (PCB) assembly plays a very important role in modern electronics manufacturing industries. Well-developed inspection machines in each assembly process are required to ensure the manufacturing quality of the electronics products. However, generally almost all AOI machines are based on 2D image-analysis technology. In this paper, a 3D-measurement-method-based AOI system is proposed consisting of a phase shifting profilometer and a stereo vision system for assembled electronic components on a PCB after component mounting and the reflow process. In this system information from two visual systems is fused to extend the shape measurement range limited by 2pi phase ambiguity of the phase shifting profilometer, and finally to maintain fine measurement resolution and high accuracy of the phase shifting profilometer with the measurement range extended by the stereo vision. The main purpose is to overcome the low inspection reliability problem of 2D-based inspection machines by using 3D information of components. The 3D shape measurement results on PCB-mounted electronic components are shown and compared with results from contact and noncontact 3D measuring machines. Based on a series of experiments, the usefulness of the proposed sensor system and its fusion technique are discussed and analyzed in detail.

  13. Manufacturing methods and technology for digital fault insulation of printed circuit boards, appendix

    NASA Astrophysics Data System (ADS)

    1980-11-01

    This report describes the manufacturing technology and test system that will enable detection, identification, and location of digital faults in the advanced missile electronic system that will be used in the 1980's. Emphasis is placed on the fault diagnosis of large printed circuit boards containing complex hybrid digital microelectronic circuits. The Hughes-enhanced, state of the art, DTS-70 automatic test system installed at Redstone Arsenal as a result of this contract provides the capability to isolate digital faults in such circuit boards to the component level with a test comprehensiveness of 90% or better.

  14. Novel waste printed circuit board recycling process with molten salt.

    PubMed

    Riedewald, Frank; Sousa-Gallagher, Maria

    2015-01-01

    The objective of the method was to prove the concept of a novel waste PCBs recycling process which uses inert, stable molten salts as the direct heat transfer fluid and, simultaneously, uses this molten salt to separate the metal products in either liquid (solder, zinc, tin, lead, etc.) or solid (copper, gold, steel, palladium, etc.) form at the operating temperatures of 450-470 °C. The PCB recovery reactor is essentially a U-shaped reactor with the molten salt providing a continuous fluid, allowing molten salt access from different depths for metal recovery. A laboratory scale batch reactor was constructed using 316L as suitable construction material. For safety reasons, the inert, stable LiCl-KCl molten salts were used as direct heat transfer fluid. Recovered materials were washed with hot water to remove residual salt before metal recovery assessment. The impact of this work was to show metal separation using molten salts in one single unit, by using this novel reactor methodology. •The reactor is a U-shaped reactor filled with a continuous liquid with a sloped bottom representing a novel reactor concept.•This method uses large PCB pieces instead of shredded PCBs as the reactor volume is 2.2 L.•The treated PCBs can be removed via leg B while the process is on-going.

  15. Novel waste printed circuit board recycling process with molten salt

    PubMed Central

    Riedewald, Frank; Sousa-Gallagher, Maria

    2015-01-01

    The objective of the method was to prove the concept of a novel waste PCBs recycling process which uses inert, stable molten salts as the direct heat transfer fluid and, simultaneously, uses this molten salt to separate the metal products in either liquid (solder, zinc, tin, lead, etc.) or solid (copper, gold, steel, palladium, etc.) form at the operating temperatures of 450–470 °C. The PCB recovery reactor is essentially a U-shaped reactor with the molten salt providing a continuous fluid, allowing molten salt access from different depths for metal recovery. A laboratory scale batch reactor was constructed using 316L as suitable construction material. For safety reasons, the inert, stable LiCl–KCl molten salts were used as direct heat transfer fluid. Recovered materials were washed with hot water to remove residual salt before metal recovery assessment. The impact of this work was to show metal separation using molten salts in one single unit, by using this novel reactor methodology. • The reactor is a U-shaped reactor filled with a continuous liquid with a sloped bottom representing a novel reactor concept. • This method uses large PCB pieces instead of shredded PCBs as the reactor volume is 2.2 L. • The treated PCBs can be removed via leg B while the process is on-going. PMID:26150977

  16. Waste printed circuit board recycling techniques and product utilization.

    PubMed

    Hadi, Pejman; Xu, Meng; Lin, Carol S K; Hui, Chi-Wai; McKay, Gordon

    2015-01-01

    E-waste, in particular waste PCBs, represents a rapidly growing disposal problem worldwide. The vast diversity of highly toxic materials for landfill disposal and the potential of heavy metal vapors and brominated dioxin emissions in the case of incineration render these two waste management technologies inappropriate. Also, the shipment of these toxic wastes to certain areas of the world for eco-unfriendly "recycling" has recently generated a major public outcry. Consequently, waste PCB recycling should be adopted by the environmental communities as an ultimate goal. This article reviews the recent trends and developments in PCB waste recycling techniques, including both physical and chemical recycling. It is concluded that the physical recycling techniques, which efficiently separate the metallic and nonmetallic fractions of waste PCBs, offer the most promising gateways for the environmentally-benign recycling of this waste. Moreover, although the reclaimed metallic fraction has gained more attention due to its high value, the application of the nonmetallic fraction has been neglected in most cases. Hence, several proposed applications of this fraction have been comprehensively examined. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Flexible printed circuit boards laser bonding using a laser beam homogenization process

    NASA Astrophysics Data System (ADS)

    Kim, Joohan; Choi, Haewoon

    2012-11-01

    A laser micro-bonding process using laser beam shaping is successfully demonstrated for flexible printed circuit boards. A CW Ytterbium fiber laser with a wavelength of 1070 nm and a laser power density of 1-7 W/mm2 is employed as a local heat source for bonding flexible printed circuit boards to rigid printed circuit boards. To improve the bonding quality, a micro-lens array is used to modify the Gaussian laser beam for the bonding process. An electromagnetic modeling and heat transfer simulation is conducted to verify the effect of the micro-lens array on the laser bonding process. The optimal bonding parameters are found experimentally. As the measured temperature ramp rate of the boards exceeds 1100 K/s, bonding occurs within 100-200 ms at a laser power density of 5 W/mm2. The bonding quality of the FPCB is verified with a shear strength test. Process characteristics are also discussed.

  18. Electro-optical circuit board with single-mode glass waveguide optical interconnects

    NASA Astrophysics Data System (ADS)

    Brusberg, Lars; Neitz, Marcel; Pernthaler, Dominik; Weber, Daniel; Sirbu, Bogdan; Herbst, Christian; Frey, Christopher; Queisser, Marco; Wöhrmann, Markus; Manessis, Dionysios; Schild, Beatrice; Oppermann, Hermann; Eichhammer, Yann; Schröder, Henning; Hâkansson, Andreas; Tekin, Tolga

    2016-03-01

    A glass optical waveguide process has been developed for fabrication of electro-optical circuit boards (EOCB). Very thin glass panels with planar integrated single-mode waveguides can be embedded as a core layer in printed circuit boards for high-speed board-level chip-to-chip and board-to-board optical interconnects over an optical backplane. Such singlemode EOCBs will be needed in upcoming high performance computers and data storage network environments in case single-mode operating silicon photonic ICs generate high-bandwidth signals [1]. The paper will describe some project results of the ongoing PhoxTroT project, in which a development of glass based single-mode on-board and board-to-board interconnection platform is successfully in progress. The optical design comprises a 500 μm thin glass panel (Schott D263Teco) with purely optical layers for single-mode glass waveguides. The board size is accommodated to the mask size limitations of the fabrication (200 mm wafer level process, being later transferred also to larger panel size). Our concept consists of directly assembling of silicon photonic ICs on cut-out areas in glass-based optical waveguide panels. A part of the electrical wiring is patterned by thin film technology directly on the glass wafer surface. A coupling element will be assembled on bottom side of the glass-based waveguide panel for 3D coupling between board-level glass waveguides and chip-level silicon waveguides. The laminate has a defined window for direct glass access for assembling of the photonic integrated circuit chip and optical coupling element. The paper describes the design, fabrication and characterization of glass-based electro-optical circuit board with format of (228 x 305) mm2.

  19. 2D Electrically Tuneable EBG Integrated Circuits

    DTIC Science & Technology

    2014-04-01

    SUBJECT TERMS meta materials, integrated circuit, Radio Frequency Transmission Lines 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...periodicity which induces the EBG and as such is not tuneable [1] if implemented as integrated circuits (IC) or printed circuit boards (PCB). 15. SUBJECT TERMS ...In light of this, a new circuit design technique was developed which showed reduced performance, but nonetheless demonstrated tuneable EBG effects

  20. Compact fluid cooled power converter supporting multiple circuit boards

    DOEpatents

    Radosevich, Lawrence D.; Meyer, Andreas A.; Beihoff, Bruce C.; Kannenberg, Daniel G.

    2005-03-08

    A support may receive one or more power electronic circuits. The support may aid in removing heat from the circuits through fluid circulating through the support. The support, in conjunction with other packaging features may form a shield from both external EMI/RFI and from interference generated by operation of the power electronic circuits. Features may be provided to permit and enhance connection of the circuitry to external circuitry, such as improved terminal configurations. Modular units may be assembled that may be coupled to electronic circuitry via plug-in arrangements or through interface with a backplane or similar mounting and interconnecting structures.

  1. All-semiconductor metamaterial-based optical circuit board at the microscale

    SciTech Connect

    Min, Li; Huang, Lirong

    2015-07-07

    The newly introduced metamaterial-based optical circuit, an analogue of electronic circuit, is becoming a forefront topic in the fields of electronics, optics, plasmonics, and metamaterials. However, metals, as the commonly used plasmonic elements in an optical circuit, suffer from large losses at the visible and infrared wavelengths. We propose here a low-loss, all-semiconductor metamaterial-based optical circuit board at the microscale by using interleaved intrinsic GaAs and doped GaAs, and present the detailed design process for various lumped optical circuit elements, including lumped optical inductors, optical capacitors, optical conductors, and optical insulators. By properly combining these optical circuit elements and arranging anisotropic optical connectors, we obtain a subwavelength optical filter, which can always hold band-stop filtering function for various polarization states of the incident electromagnetic wave. All-semiconductor optical circuits may provide a new opportunity in developing low-power and ultrafast components and devices for optical information processing.

  2. All-semiconductor metamaterial-based optical circuit board at the microscale

    NASA Astrophysics Data System (ADS)

    Min, Li; Huang, Lirong

    2015-07-01

    The newly introduced metamaterial-based optical circuit, an analogue of electronic circuit, is becoming a forefront topic in the fields of electronics, optics, plasmonics, and metamaterials. However, metals, as the commonly used plasmonic elements in an optical circuit, suffer from large losses at the visible and infrared wavelengths. We propose here a low-loss, all-semiconductor metamaterial-based optical circuit board at the microscale by using interleaved intrinsic GaAs and doped GaAs, and present the detailed design process for various lumped optical circuit elements, including lumped optical inductors, optical capacitors, optical conductors, and optical insulators. By properly combining these optical circuit elements and arranging anisotropic optical connectors, we obtain a subwavelength optical filter, which can always hold band-stop filtering function for various polarization states of the incident electromagnetic wave. All-semiconductor optical circuits may provide a new opportunity in developing low-power and ultrafast components and devices for optical information processing.

  3. WindoWorks: A flexible program for computerized testing of accelerator control system electronic circuit boards

    SciTech Connect

    Utterback, J.

    1993-09-01

    Since most accelerator control system circuit boards reside in a commercial bus architecture, such as CAMAC or VMEbus, a computerized test station is needed for exercising the boards. This test station is needed for the development of newly designed prototypes, for commissioning newly manufactured boards, for diagnosing boards which have failed in service, and for long term testing of boards with intermittent failure problems. WindoWorks was created to address these needs. It is a flexible program which runs on a PC compatible computer and uses a PC to bus crate interface. WindoWorks was designed to give the user a flexible way to test circuit boards. Each test is incapsulated into a window. By bringing up several different windows the user can run several different tests simultaneously. The windows are sizable, and moveable. They have data entry boxes so that the test can be customized to the users preference. The windows can be used in conjunction with each other in order to create supertests. There are several windows which are generic. They can be used to test basic functions on any VME (or CAMAC) board. There are other windows which have been created to test specific boards. New windows for testing specific boards can be easily created by a Pascal programmer using the WindoWorks framework.

  4. Effect of Bypass Capacitor in Common-mode Noise Reduction Technique for Automobile PCB

    NASA Astrophysics Data System (ADS)

    Uno, Takanori; Ichikawa, Kouji; Mabuchi, Yuichi; Nakamura, Atushi

    In this letter, we studied the use of common mode noise reduction technique for in-vehicle electronic equipment, each comprising large-scale integrated circuit (LSI), printed circuit board (PCB), wiring harnesses, and ground plane. We have improved the model circuit of the common mode noise that flows to the wire harness to add the effect of by-pass capacitors located near an LSI.

  5. Modal testing circuit board assembly of an electronic apparatus by laser vibrometry

    NASA Astrophysics Data System (ADS)

    Krasnoveikin, V. A.; Smolin, I. Yu; Druzhinin, N. V.; Kolubaev, E. A.; Derusova, D. A.

    2016-11-01

    The operating capacity and service life of printed circuit boards in various electronic equipment and devices depends on their ability to resist vibroacoustic loads, including vibration and acoustic noises. In this paper, non-contact laser vibrometry has been applied to perform the modal analysis of a circuit board assembly in order to identify its vulnerable spots and to find solutions to protect the assembly from external vibroacoustic loads. A broadband periodic chirp signal was used to excite vibration, which enabled a rapid generation of results. The paper provides data on eigenfrequencies, vibration velocity fields, and vibration displacement profiles. Frequency ranges have been determined in which eigenfrequencies with the highest vibration amplification lie. The obtained data can be used to develop a quality control technique for printed circuit boards and to optimize their construction as early as the design stage.

  6. A new two-roll electrostatic separator for recycling of metals and nonmetals from waste printed circuit board.

    PubMed

    Jiang, Wu; Jia, Li; Zhen-Ming, Xu

    2009-01-15

    The electrostatic separation is an effective method for recycling waste electrical and electronic equipment (WEEE). The efficiency of electrostatic separation processes depends on the ability of the separator. As a classical one, the roll-type corona-electrostatic separator has some advantages in recycling metals and plastics from waste printed circuit board (PCB). However, its industry application still faces some problems, such as: the further disposal of the middling products of the separation process; the balance of the production capacity and the good separation efficiency; the separation of the fine granular mixture and the stability of the separation process. A new "two-roll-type corona-electrostatic separator" was built to overcome the limitation of the classical one. The experimental data were discussed and the results showed that the outcome of the separation process was improved by using the new separator. Compared with the classical machine, the mass of conductive products increases 8.9% (groups 2 and 3) and10.2% (group 4) while the mass of the middling products decreases 45% (groups 2 and 3) and 31.7% (group 4), respectively. The production capacity of the new machine increases, and the stability of the separation process is enhanced.

  7. Printed Circuit Board Surface Finish and Effects of Chloride Contamination, Electric Field, and Humidity on Corrosion Reliability

    NASA Astrophysics Data System (ADS)

    Conseil-Gudla, Hélène; Jellesen, Morten S.; Ambat, Rajan

    2017-02-01

    Corrosion reliability is a serious issue today for electronic devices, components, and printed circuit boards (PCBs) due to factors such as miniaturization, globalized manufacturing practices which can lead to process-related residues, and global usage effects such as bias voltage and unpredictable user environments. The investigation reported in this paper focuses on understanding the synergistic effect of such parameters, namely contamination, humidity, PCB surface finish, pitch distance, and potential bias on leakage current under different humidity levels, and electrochemical migration probability under condensing conditions. Leakage currents were measured on interdigitated comb test patterns with three different types of surface finish typically used in the electronics industry, namely gold, copper, and tin. Susceptibility to electrochemical migration was studied under droplet conditions. The level of base leakage current (BLC) was similar for the different surface finishes and NaCl contamination levels up to relative humidity (RH) of 65%. A significant increase in leakage current was found for comb patterns contaminated with NaCl above 70% to 75% RH, close to the deliquescent RH of NaCl. Droplet tests on Cu comb patterns with varying pitch size showed that the initial BLC before dendrite formation increased with increasing NaCl contamination level, whereas electrochemical migration and the frequency of dendrite formation increased with bias voltage. The effect of different surface finishes on leakage current under humid conditions was not very prominent.

  8. Critical rotational speed model of the rotating roll electrode in corona electrostatic separation for recycling waste printed circuit boards.

    PubMed

    Li, Jia; Lu, Hongzhou; Xu, Zhenming; Zhou, Yaohe

    2008-06-15

    Waste printed circuit board (PCB) is increasing worldwide. The corona electrostatic separation (CES) was an effective and environmental protection way to recycle resource from waste PCBs. The aim of this paper is to analyze the main factor (rotational speed) that affects the efficiency of CES from the point of view of electrostatics and mechanics. A quantitative method for analyzing the affection of rotational speed was studied and the model for separating flat nonmetal particles in waste PCBs was established. The conception of "charging critical rotational speed" and "detaching critical rotational speed" were presented. Experiments with the waste PCBs verified the theoretical model, and the experimental results were in good agreement with the theoretical model. The results indicated that the purity and recycle percentage of materials got a good level when the rotational speed was about 70 rpm and the critical rotational speed of small particles was higher than big particles. The model can guide the definition of operator parameter and the design of CES, which are needed for the development of any new application of the electrostatic separation method.

  9. Ingestion of computer circuit boards causing esophageal impaction and small bowel obstruction

    PubMed Central

    Saleem, Nasir

    2017-01-01

    Foreign body ingestion is common in patients with psychiatric diagnoses. Ingested objects can become impacted in the upper and lower gastrointestinal tract, causing serious complications. We report a case of a schizophrenic who ingested large pieces of computer circuit boards, which impacted at the mid-esophagus, in the stomach, and in the cecum. Endoscopic removal of the esophageal object was unsuccessful, and the foreign objects were removed by esophagotomy and laparotomy. Expeditious removal through endoscopic or surgical means is extremely important, as complications can be life-threatening. This is the first report of ingestion of a computer printed circuit board. PMID:28127146

  10. Printed circuit board for a CCD camera head

    DOEpatents

    Conder, Alan D.

    2002-01-01

    A charge-coupled device (CCD) camera head which can replace film for digital imaging of visible light, ultraviolet radiation, and soft to penetrating x-rays, such as within a target chamber where laser produced plasmas are studied. The camera head is small, capable of operating both in and out of a vacuum environment, and is versatile. The CCD camera head uses PC boards with an internal heat sink connected to the chassis for heat dissipation, which allows for close (0.04" for example) stacking of the PC boards. Integration of this CCD camera head into existing instrumentation provides a substantial enhancement of diagnostic capabilities for studying high energy density plasmas, for a variety of military industrial, and medical imaging applications.

  11. Analytical modeling of multi-layered Printed Circuit Board dedicated to electronic component thermal characterization

    NASA Astrophysics Data System (ADS)

    Monier-Vinard, Eric; Laraqi, Najib; Dia, Cheikh-Tidiane; Nguyen, Minh-Nhat; Bissuel, Valentin

    2015-01-01

    Electronic components are continuously getting smaller and embedding more and more powered functions which exacerbate the temperature rise in component/board interconnect areas. For still air conditions, the heat spreading of the component power is mainly done through the surrounding metallic planes of its electronic board. Their design optimization is henceforth mandatory to control the temperature and to preserve component reliability. To allow the electronic designer to early analyze the limits of the power dissipation of miniaturized devices, an analytical model of a multi-layered electronic board was established with the purpose to assess the validity of conventional board modeling approach. For decades, numerous authors have been promoting a homogenous single layer model that summed up the layers of the board using effective orthotropic thermal properties. The derived compact model depends on thermal properties approximation which is commonly based on parallel conduction model given a linear rule of mixture. The work presents the thermal behavior comparison of a detailed multi-layer representation to its deducted compact model for an extensive set of variable parameters, such as heat transfer coefficients, effective thermal conductivities calculation models, number of trace layers, trace coverage or source size. The results highlight the fact that the conventional practices for PCB modeling can dramatically underestimate source temperatures when their size is getting very small.

  12. Designing High Speed Printed Circuit Boards Using DxDesigner and Expedition

    NASA Technical Reports Server (NTRS)

    Navarro, Robert

    2007-01-01

    Mentor's DxDesigner and Expedition schematic capture and printed circuit board tools were chosen to implement a custom high speed signal processing board containing many high pin count Field Programmable Gate Arrays and many high speed serial connections with data rates over 2 Gigasamples/sec. The methodology used to place the parts and route the board involved the interaction of both the DxDesigner and Expedition tools. The basic design philosophy was to specify as much as possible through design constraints at the schematic level. This paper will explore implementing that philosophy in both tools to facilitate part placement and trace routing.

  13. A filter circuit board for the Earthworm Seismic Data Acquisition System

    USGS Publications Warehouse

    Jensen, Edward Gray

    2000-01-01

    The Earthworm system is a seismic network data acquisition and processing system used by the Northern California Seismic Network as well as many other seismic networks. The input to the system is comprised of many realtime electronic waveforms fed to a multi-channel digitizer on a PC platform. The digitizer consists of one or more National Instruments Corp. AMUX–64T multiplexer boards attached to an A/D converter board located in the computer. Originally, passive filters were installed on the multiplexers to eliminate electronic noise picked up in cabling. It was later discovered that a small amount of crosstalk occurred between successive channels in the digitizing sequence. Though small, this crosstalk will cause what appear to be small earthquake arrivals at the wrong time on some channels. This can result in erroneous calculation of earthquake arrival times, particularly by automated algorithms. To deal with this problem, an Earthworm filter board was developed to provide the needed filtering while eliminating crosstalk. This report describes the tests performed to find a suitable solution, and the design of the circuit board. Also included are all the details needed to build and install this board in an Earthworm system or any other system using the AMUX–64T board. Available below is the report in PDF format as well as an archive file containing the circuit board manufacturing information.

  14. Waste Minimization in Circuit Board Manufacturing by PARMOD(TM) Technology

    DTIC Science & Technology

    2007-11-02

    been the basis of further development and evaluation in selected markets . A Dual Use application to prototyping printed wiring boards and metallizing...Results 59 Conclusions 61 Commercialization Technical Activities 62 Technology Management & Funding (TMF) 62 Sales & Marketing Process Management...C-03 54 June, 1998 Methods. Assumptions and Procedures Sample Circuit Preparation Ink Paste Preparation The ink components are mixed in a glove

  15. Circuit Board Analysis for Lead by Atomic Absorption Spectroscopy in a Course for Nonscience Majors

    ERIC Educational Resources Information Center

    Weidenhammer, Jeffrey D.

    2007-01-01

    A circuit board analysis of the atomic absorption spectroscopy, which is used to measure lead content in a course for nonscience majors, is being presented. The experiment can also be used to explain the potential environmental hazards of unsafe disposal of various used electronic equipments.

  16. An Integer Programming-Based Generalized Vehicle Routing Approach for Printed Circuit Board Assembly Optimization

    ERIC Educational Resources Information Center

    Seth, Anupam

    2009-01-01

    Production planning and scheduling for printed circuit, board assembly has so far defied standard operations research approaches due to the size and complexity of the underlying problems, resulting in unexploited automation flexibility. In this thesis, the increasingly popular collect-and-place machine configuration is studied and the assembly…

  17. Circuit Board Analysis for Lead by Atomic Absorption Spectroscopy in a Course for Nonscience Majors

    ERIC Educational Resources Information Center

    Weidenhammer, Jeffrey D.

    2007-01-01

    A circuit board analysis of the atomic absorption spectroscopy, which is used to measure lead content in a course for nonscience majors, is being presented. The experiment can also be used to explain the potential environmental hazards of unsafe disposal of various used electronic equipments.

  18. An Integer Programming-Based Generalized Vehicle Routing Approach for Printed Circuit Board Assembly Optimization

    ERIC Educational Resources Information Center

    Seth, Anupam

    2009-01-01

    Production planning and scheduling for printed circuit, board assembly has so far defied standard operations research approaches due to the size and complexity of the underlying problems, resulting in unexploited automation flexibility. In this thesis, the increasingly popular collect-and-place machine configuration is studied and the assembly…

  19. The application of printed circuit board technology for fabrication of multi-channel micro-drives.

    PubMed

    Szabó, I; Czurkó, A; Csicsvari, J; Hirase, H; Leinekugel, X; Buzsáki, G

    2001-01-30

    A modular multichannel microdrive ('hyperdrive') is described. The microdrive uses printed circuit board technology and flexible fused silica capillaries. The modular design allows for the fabrication of 4-32 independently movable electrodes or 'tetrodes'. The drives are re-usable and re-loading the drive with electrodes is simple.

  20. Bioextraction of Copper from Printed Circuit Boards: Influence of Initial Concentration of Ferrous Iron

    NASA Astrophysics Data System (ADS)

    Yamane, Luciana Harue; Espinosa, Denise Crocce Romano; Tenório, Jorge Alberto Soares

    Printed circuit boards are found in all electric and electronic equipment and are particularly problematic to recycle because of the heterogeneous mix of organic material, metals, and fiberglass. Additionally, printed circuit boards can be considered a secondary source of copper and bacterial leaching can be applied to copper recovery. This study investigated the influence of initial concentration of ferrous iron on bacterial leaching to recover copper from printed circuit boards using Acidithiobacillus ferrooxidans-LR. Printed circuit boards from computers were comminuted using a hammer mill. The powder obtained was magnetically separated and the non magnetic material used in this study. A shake flask study was carried out on the non magnetic material using a rotary shaker at 30°C, 170 rpm and different initial concentrations of ferrous iron (gL-1): 6.75; 13.57 and 16.97. Abiotic controls were also run in parallel. The monitored parameters were pH, Eh, ferrous iron concentration and copper extraction (spectroscopy of atomic absorption). The results showed that using initial concentration of ferrous iron of 6.75gL-1 were extracted 99% of copper by bacterial leaching.

  1. Development of a semi-automated workcell for repair of printed circuit boards

    SciTech Connect

    Bennett, D.W.; Evans, M.S.

    1990-08-01

    Printed circuit boards that comprise US Army electronic systems are repaired at Army depots. An existing automated diagnostic system determines the area of failure; either by identifying failed components or failed board traces. Currently, repairs are performed manually by trained technicians. A system is being developed for repair of through-hole printed circuit boards. It is comprised of many automated and operator-assisted functions to perform the multiple operations related to replacement of failed components. When completed, this system will demonstrate economic payback by reducing skilled labor requirements and decreasing rework. The semi-automated system integrates human operators into the process while maintaining high productivity. After several fully automated systems were conceived and modelled, it was found that the configuration that provided the best return on investment was comprised of a mix of autonomous and operator-assisted functions. 1 ref., 1 fig.

  2. Feasibility Test of a Liquid Film Thickness Sensor on a Flexible Printed Circuit Board Using a Three-Electrode Conductance Method

    PubMed Central

    Lee, Kyu Byung; Kim, Jong Rok; Park, Goon Cherl; Cho, Hyoung Kyu

    2016-01-01

    Liquid film thickness measurements under temperature-varying conditions in a two-phase flow are of great importance to refining our understanding of two-phase flows. In order to overcome the limitations of the conventional electrical means of measuring the thickness of a liquid film, this study proposes a three-electrode conductance method, with the device fabricated on a flexible printed circuit board (FPCB). The three-electrode conductance method offers the advantage of applicability under conditions with varying temperatures in principle, while the FPCB has the advantage of usability on curved surfaces and in relatively high-temperature conditions in comparison with sensors based on a printed circuit board (PCB). Two types of prototype sensors were fabricated on an FPCB and the feasibility of both was confirmed in a calibration test conducted at different temperatures. With the calibrated sensor, liquid film thickness measurements were conducted via a falling liquid film flow experiment, and the working performance was tested. PMID:28036000

  3. Size Effect of Ground Patterns on FM-Band Cross-Talks between Two Parallel Signal Traces of Printed Circuit Boards for Vehicles

    NASA Astrophysics Data System (ADS)

    Iida, Michihira; Maeno, Tsuyoshi; Wang, Jianqing; Fujiwara, Osamu

    Electromagnetic disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring-harnesses from vehicle-mounted printed circuit boards (PCBs) with common slitting ground patterns. To suppress these kinds of noise currents, we previously measured them for simple two-layer PCBs with two parallel signal traces and slitting or non-slitting ground patterns, and then investigated by the FDTD simulation the reduction characteristics of the FM-band cross-talk noise levels between two parallel signal traces on six simple PCB models having different slitting ground or different divided ground patterns parallel to the traces. As a result, we found that the contributory factor for the FM-band cross-talk reduction is the reduction of mutual inductance between the two parallel traces, and also the noise currents from PCBs can rather be suppressed even if the size of the return ground becomes small. In this study, to investigate this finding, we further simulated the frequency characteristics of cross-talk reduction for additional six simple PCB models with different dividing dimensions ground patterns parallel to the traces, which revealed an interesting phenomenon that cross-talk reduction characteristics do not always decrease with increasing the width between the divided ground patterns.

  4. A comparison of gold versus silver electrode contacts for high-resolution gastric electrical mapping using flexible printed circuit board arrays.

    PubMed

    O'Grady, G; Paskaranandavadivel, N; Angeli, T R; Du, P; Windsor, J A; Cheng, L K; Pullan, A J

    2011-03-01

    Stomach contractions are initiated and coordinated by electrical events termed slow waves, and slow wave abnormalities contribute to gastric motility disorders. Recently, flexible printed circuit board (PCB) multi-electrode arrays were introduced, facilitating high-resolution mapping of slow wave activity in humans. However PCBs with gold contacts have shown a moderately inferior signal quality to previous custom-built silver-wire platforms, potentially limiting analyses. This study determined if using silver instead of gold contacts improved flexible PCB performance. In a salt-bath test, modestly higher stimulus amplitudes were recorded from silver PCBs (mean 312, s.d. 89 µV) than those from gold (mean 281, s.d. 85 µV) (p < 0.001); however, the signal-to-noise ratio (SNR) was similar (p = 0.26). In eight in vivo experimental studies, involving gastric serosal recordings from five pigs, no silver versus gold differences were found in terms of slow wave amplitudes (mean 677 versus 682 µV; p = 0.91), SNR (mean 8.8 versus 8.8 dB; p = 0.94) or baseline drift (NRMS; mean 12.0 versus 12.1; p = 0.97). Under the prescribed conditions, flexible PCBs with silver or gold contacts provide comparable results in vivo, and contact material difference does not explain the performance difference between current-generation slow wave mapping platforms. Alternative explanations for this difference and the implications for electrode design are discussed.

  5. A cytokine immunosensor for Multiple Sclerosis detection based upon label-free electrochemical impedance spectroscopy using electroplated printed circuit board electrodes.

    PubMed

    Bhavsar, Kinjal; Fairchild, Aaron; Alonas, Eric; Bishop, Daniel K; La Belle, Jeffrey T; Sweeney, James; Alford, T L; Joshi, Lokesh

    2009-10-15

    A biosensor for the serum cytokine, Interleukin-12 (IL-12), based upon a label-free electrochemical impedance spectroscopy (EIS) monitoring approach is described. Overexpression of IL-12 has been correlated to the diagnosis of Multiple Sclerosis (MS). An immunosensor has been fabricated by electroplating gold onto a disposable printed circuit board (PCB) electrode and immobilizing anti-IL-12 monoclonal antibodies (MAb) onto the surface of the electrode. This approach yields a robust sensor that facilitates reproducible mass fabrication and easy alteration of the electrode shape. Results indicate that this novel PCB sensor can detect IL-12 at physiological levels, <100 fM with f-values of 0.05 (typically <0.0001) in a label-free and rapid manner. A linear (with respect to log concentration) detectable range was achieved. Detection in a complex biological solution is also explored; however, significant loss of dynamic range is noted in the 100% complex solution. The cost effective approach described here can be used potentially for diagnosis of diseases (like MS) with known biomarkers in body fluids and for monitoring physiological levels of biomolecules with healthcare, food, and environmental relevance.

  6. A comparison of gold vs silver electrode contacts for high-resolution gastric electrical mapping using flexible printed circuit board arrays

    PubMed Central

    O’Grady, G; Paskaranandavadivel, N; Angeli, T R; Du, P; Windsor, J A; Cheng, L K; Pullan, A J

    2014-01-01

    Stomach contractions are initiated and coordinated by electrical events termed slow waves, and slow wave abnormalities contribute to gastric motility disorders. Recently, flexible printed circuit board (PCB) multi-electrode arrays were introduced, facilitating high-resolution mapping of slow wave activity in humans. However PCBs with gold-contacts have shown a moderately inferior signal quality to previous custom-built silver-wire platforms, potentially limiting analyses. This study determined if using silver instead of gold contacts improved flexible PCB performance. In a salt-bath test, modestly higher stimulus amplitudes were recorded from silver PCBs (mean 312 s.d. 89 μV) than gold (mean 281 s.d. 85 μV) (p<0.001); however the signal to noise ratio (SNR) was similar (p=0.26). In eight in-vivo experimental studies, involving gastric serosal recordings from five pigs, no silver vs gold differences were found in terms of slow wave amplitudes (mean 677 vs 682 μV; p=0.91), SNR (mean 8.8 vs 8.8 dB; p=0.94) or baseline drift (NMRS; mean 12.0 vs 12.1; p=0.97). Under the prescribed conditions, flexible PCBs with silver or gold contacts provide comparable results in-vivo, and contact material difference does not explain the performance difference between current-generation slow wave mapping platforms. Alternative explanations for this difference and the implications for electrode design are discussed. PMID:21252419

  7. Circuit board accident--organizational dimension hidden by prescribed safety.

    PubMed

    de Almeida, Ildeberto Muniz; Buoso, Eduardo; do Amaral Dias, Maria Dionísia; Vilela, Rodolfo Andrade Gouveia

    2012-01-01

    This study analyzes an accident in which two maintenance workers suffered severe burns while replacing a circuit breaker panel in a steel mill, following model of analysis and prevention of accidents (MAPA) developed with the objective of enlarging the perimeter of interventions and contributing to deconstruction of blame attribution practices. The study was based on materials produced by a health service team in an in-depth analysis of the accident. The analysis shows that decisions related to system modernization were taken without considering their implications in maintenance scheduling and creating conflicts of priorities and of interests between production and safety; and also reveals that the lack of a systemic perspective in safety management was its principal failure. To explain the accident as merely non-fulfillment of idealized formal safety rules feeds practices of blame attribution supported by alibi norms and inhibits possible prevention. In contrast, accident analyses undertaken in worker health surveillance services show potential to reveal origins of these events incubated in the history of the system ignored in practices guided by the traditional paradigm.

  8. PERSONAL COMPUTER MONITORS: A SCREENING EVALUATION OF VOLATILE ORGANIC EMISSIONS FROM EXISTING PRINTED CIRCUIT BOARD LAMINATES AND POTENTIAL POLLUTION PREVENTION ALTERNATIVES

    EPA Science Inventory

    The report gives results of a screening evaluation of volatile organic emissions from printed circuit board laminates and potential pollution prevention alternatives. In the evaluation, printed circuit board laminates, without circuitry, commonly found in personal computer (PC) m...

  9. PERSONAL COMPUTER MONITORS: A SCREENING EVALUATION OF VOLATILE ORGANIC EMISSIONS FROM EXISTING PRINTED CIRCUIT BOARD LAMINATES AND POTENTIAL POLLUTION PREVENTION ALTERNATIVES

    EPA Science Inventory

    The report gives results of a screening evaluation of volatile organic emissions from printed circuit board laminates and potential pollution prevention alternatives. In the evaluation, printed circuit board laminates, without circuitry, commonly found in personal computer (PC) m...

  10. Effect of Ground Patterns Size on FM-Band Cross-Talks between Two Parallel Signal Traces of Printed Circuit Boards for Vehicles

    NASA Astrophysics Data System (ADS)

    Iida, Michihira; Maeno, Tsuyoshi; Fujiwara, Osamu

    It is well known that electromagnetic disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring-harnesses from vehicle-mounted printed circuit boards (PCBs) with common ground patterns containing slits. To suppress the noise currents outflow from PCBs of these kinds, we previously measured noise currents outflow from simple two-layer PCBs having two parallel signal traces and different ground patterns with/without slits to reveal that making slits with open ends on the ground patterns in parallel with the traces can reduce the conducted noise currents. In the present study, with FDTD simulation, we investigated reduction effects of ground patterns size on the FM-band cross-talk noise levels between two parallel signal traces, by using four types of simple PCB models having different ground patterns formed in different numbers but containing the same planar dimension slits parallel to the traces, in addition to two types of PCB models with different ground patterns divided into two parts parallel to the traces. As a result, we found that the cross-talk noise currents for the above six types of PCBs decrease by 6.9-8.5dB compared to the PCB which has a plain ground with no slits. From this study, we got the finding that the contributing factor for the above mentioned cross-talk reduction relies on the reduction of mutual inductance between the two parallel traces. In addition, in case of this study, it is interesting to note that the noise currents outflow from PCBs can rather be suppressed when the size of the return ground of each signal trace is small.

  11. Highly flexible self-powered sensors based on printed circuit board technology for human motion detection and gesture recognition.

    PubMed

    Fuh, Yiin-Kuen; Ho, Hsi-Chun

    2016-03-04

    In this paper, we demonstrate a new integration of printed circuit board (PCB) technology-based self-powered sensors (PSSs) and direct-write, near-field electrospinning (NFES) with polyvinylidene fluoride (PVDF) micro/nano fibers (MNFs) as source materials. Integration with PCB technology is highly desirable for affordable mass production. In addition, we systematically investigate the effects of electrodes with intervals in the range of 0.15 mm to 0.40 mm on the resultant PSS output voltage and current. The results show that at a strain of 0.5% and 5 Hz, a PSS with a gap interval 0.15 mm produces a maximum output voltage of 3 V and a maximum output current of 220 nA. Under the same dimensional constraints, the MNFs are massively connected in series (via accumulation of continuous MNFs across the gaps ) and in parallel (via accumulation of parallel MNFs on the same gap) simultaneously. Finally, encapsulation in a flexible polymer with different interval electrodes demonstrated that electrical superposition can be realized by connecting MNFs collectively and effectively in serial/parallel patterns to achieve a high current and high voltage output, respectively. Further improvement in PSSs based on the effect of cooperativity was experimentally realized by rolling-up the device into a cylindrical shape, resulting in a 130% increase in power output due to the cooperative effect. We assembled the piezoelectric MNF sensors on gloves, bandages and stockings to fabricate devices that can detect different types of human motion, including finger motion and various flexing and extensions of an ankle. The firmly glued PSSs were tested on the glove and ankle respectively to detect and harvest the various movements and the output voltage was recorded as ∼1.5 V under jumping movement (one PSS) and ∼4.5 V for the clenched fist with five fingers bent concurrently (five PSSs). This research shows that piezoelectric MNFs not only have a huge impact on harvesting various external

  12. Highly flexible self-powered sensors based on printed circuit board technology for human motion detection and gesture recognition

    NASA Astrophysics Data System (ADS)

    Fuh, Yiin-Kuen; Ho, Hsi-Chun

    2016-03-01

    In this paper, we demonstrate a new integration of printed circuit board (PCB) technology-based self-powered sensors (PSSs) and direct-write, near-field electrospinning (NFES) with polyvinylidene fluoride (PVDF) micro/nano fibers (MNFs) as source materials. Integration with PCB technology is highly desirable for affordable mass production. In addition, we systematically investigate the effects of electrodes with intervals in the range of 0.15 mm to 0.40 mm on the resultant PSS output voltage and current. The results show that at a strain of 0.5% and 5 Hz, a PSS with a gap interval 0.15 mm produces a maximum output voltage of 3 V and a maximum output current of 220 nA. Under the same dimensional constraints, the MNFs are massively connected in series (via accumulation of continuous MNFs across the gaps ) and in parallel (via accumulation of parallel MNFs on the same gap) simultaneously. Finally, encapsulation in a flexible polymer with different interval electrodes demonstrated that electrical superposition can be realized by connecting MNFs collectively and effectively in serial/parallel patterns to achieve a high current and high voltage output, respectively. Further improvement in PSSs based on the effect of cooperativity was experimentally realized by rolling-up the device into a cylindrical shape, resulting in a 130% increase in power output due to the cooperative effect. We assembled the piezoelectric MNF sensors on gloves, bandages and stockings to fabricate devices that can detect different types of human motion, including finger motion and various flexing and extensions of an ankle. The firmly glued PSSs were tested on the glove and ankle respectively to detect and harvest the various movements and the output voltage was recorded as ∼1.5 V under jumping movement (one PSS) and ∼4.5 V for the clenched fist with five fingers bent concurrently (five PSSs). This research shows that piezoelectric MNFs not only have a huge impact on harvesting various external

  13. An innovative approach to predict technology evolution for the desoldering of printed circuit boards: A perspective from China and America.

    PubMed

    Wang, Chen; Zhao, Wu; Wang, Jie; Chen, Ling; Luo, Chun-Jing

    2016-06-01

    The printed circuit boards basis of electronic equipment have seen a rapid growth in recent years and played a significant role in modern life. Nowadays, the fact that electronic devices upgrade quickly necessitates a proper management of waste printed circuit boards. Non-destructive desoldering of waste printed circuit boards becomes the first and the most crucial step towards recycling electronic components. Owing to the diversity of materials and components, the separation process is difficult, which results in complex and expensive recovery of precious materials and electronic components from waste printed circuit boards. To cope with this problem, we proposed an innovative approach integrating Theory of Inventive Problem Solving (TRIZ) evolution theory and technology maturity mapping system to forecast the evolution trends of desoldering technology of waste printed circuit boards. This approach can be applied to analyse the technology evolution, as well as desoldering technology evolution, then research and development strategy and evolution laws can be recommended. As an example, the maturity of desoldering technology is analysed with a technology maturity mapping system model. What is more, desoldering methods in different stages are analysed and compared. According to the analysis, the technological evolution trends are predicted to be 'the law of energy conductivity' and 'increasing the degree of idealisation'. And the potential technology and evolutionary state of waste printed circuit boards are predicted, offering reference for future waste printed circuit boards recycling.

  14. Thermal verification testing of commercial printed-circuit boards for spaceflight

    NASA Technical Reports Server (NTRS)

    Foster, William M., II

    1992-01-01

    A method developed to verify commercial printed-circuit boards for a Shuttle orbital flight is discussed. The test sequence is based on early fault detection, desire to test the final assembly, and integration with other verification testing. A component thermal screening test is performed first to force flaws in design, workmanship, parts, processes, and materials into observable failures. Temperature definition and vibration tests are performed next. Final assembly testing is performed to simulate the Shuttle flight. An abbreviated thermal screening test is performed as a check after the vibration test, and then a complete thermal operational test is performed. The final assembly test finishes up with a burn-in of 100 h of trouble-free operation. Verification is successful when all components and final assemblies have passed each test. This method was very successful in verifying that commercial printed-circuit boards will survive in the Shuttle environment.

  15. A Formal Algorithm for Routing Traces on a Printed Circuit Board

    NASA Technical Reports Server (NTRS)

    Hedgley, David R., Jr.

    1996-01-01

    This paper addresses the classical problem of printed circuit board routing: that is, the problem of automatic routing by a computer other than by brute force that causes the execution time to grow exponentially as a function of the complexity. Most of the present solutions are either inexpensive but not efficient and fast, or efficient and fast but very costly. Many solutions are proprietary, so not much is written or known about the actual algorithms upon which these solutions are based. This paper presents a formal algorithm for routing traces on a print- ed circuit board. The solution presented is very fast and efficient and for the first time speaks to the question eloquently by way of symbolic statements.

  16. Thermal verification testing of commercial printed-circuit boards for spaceflight

    NASA Technical Reports Server (NTRS)

    Foster, William M., II

    1992-01-01

    A method developed to verify commercial printed-circuit boards for a Shuttle orbital flight is discussed. The test sequence is based on early fault detection, desire to test the final assembly, and integration with other verification testing. A component thermal screening test is performed first to force flaws in design, workmanship, parts, processes, and materials into observable failures. Temperature definition and vibration tests are performed next. Final assembly testing is performed to simulate the Shuttle flight. An abbreviated thermal screening test is performed as a check after the vibration test, and then a complete thermal operational test is performed. The final assembly test finishes up with a burn-in of 100 h of trouble-free operation. Verification is successful when all components and final assemblies have passed each test. This method was very successful in verifying that commercial printed-circuit boards will survive in the Shuttle environment.

  17. Differential microfluidic sensor on printed circuit board for biological cells analysis.

    PubMed

    Shi, Dongyuan; Guo, Jinhong; Chen, Liang; Xia, Chuncheng; Yu, Zhefeng; Ai, Ye; Li, Chang Ming; Kang, Yuejun; Wang, Zhiming

    2015-08-01

    Coulter principal based resistive pulse sensor has been demonstrated as an important platform in biological cell detection and enumeration since several decades ago. Recently, the miniaturized micro-Coulter counter has attracted much attention due to its advantages in point of care diagnostics for on chip detection and enumeration of rare cells, such as circulating tumor cells. In this paper, we present a microfluidic cytometer with differential amplifier based on Coulter principle on a SU-8 coated printed circuit board substrate. The electrical current changes induced by the blockage of the microparticles in the sensing aperture are calibrated by polystyrene particles of standard size. Finally, HeLa cells are used to evaluate the performance of the proposed device for enumeration of biological samples. The proposed cytometer is built upon the cheap and widely available printed circuit board substrate and shows its great potential as personalized healthcare monitor. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. The separation of waste printed circuit board by dissolving bromine epoxy resin using organic solvent.

    PubMed

    Zhu, P; Chen, Y; Wang, L Y; Zhou, M; Zhou, J

    2013-02-01

    Separation of waste printed circuit boards (WPCBs) has been a bottleneck in WPCBs resource processing. In this study, the separation of WPCBs was performed using dimethyl sulfoxide (DMSO) as a solvent. Various parameters, which included solid to liquid ratio, temperature, WPCB sizes, and time, were studied to understand the separation of WPCBs by dissolving bromine epoxy resin using DMSO. Experimental results showed that the concentration of dissolving the bromine epoxy resin increased with increasing various parameters. The optimum condition of complete separation of WPCBs was solid to liquid ratio of 1:7 and WPCB sizes of 16 mm(2) at 145°C for 60 min. The used DMSO was vapored under the decompression, which obtained the regenerated DMSO and dissolved bromine epoxy resin. This clean and non-polluting technology offers a new way to separate valuable materials from WPCBs and prevent the environmental pollution of waste printed circuit boards effectively.

  19. Thermoelastic properties of plain weave composites for circuit board applications: A comparison of models and experiments

    SciTech Connect

    Ockers, J.M.; Sottos, N.R.

    1994-12-31

    The results of several micromechanical models are presented for predicting the properties of woven glass epoxy substrates used in multilayer circuit boards. Two new models are formulated and the predictions of the elastic moduli, Poisson`s ratios, and expansion coefficients are compared with the results of previously developed one and two dimensional models. The properties of several commercially pressed circuit boards are determined experimentally and compared with all of the different models. One of the newly proposed models, which does not use classical lamination theory, results in a significant improvement for the prediction of the Poisson`s ratios. Finally, parametric studies are performed to predict the influence of fabric geometry on the in-plane thermal expansion coefficients and elastic moduli. Optimal weaving parameters are identified which lead to improved dimensional stability.

  20. Volatile organic compounds and metal leaching from composite products made from fiberglass-resin portion of printed circuit board waste.

    PubMed

    Guo, Jie; Jiang, Ying; Hu, Xiaofang; Xu, Zhenming

    2012-01-17

    This study focused on the volatile organic compounds (VOCs) and metal leaching from three kinds of composite products made from fiberglass-resin portion (FRP) of crushed printed circuit board (PCB) waste, including phenolic molding compound (PMC), wood plastic composite (WPC), and nonmetallic plate (NMP). Released VOCs from the composite products were quantified by air sampling on adsorbent followed by thermal desorption and GC-MS analysis. The results showed that VOCs emitted from composite products originated from the added organic components during manufacturing process. Phenol in PMC panels came primarily from phenolic resin, and the airborne concentration of phenol emitted from PMC product was 59.4 ± 6.1 μg/m(3), which was lower than odor threshold of 100% response for phenol (180 μg/m(3)). VOCs from WPC product mainly originated from wood flour, e.g., benzaldehyde, octanal, and d-limonene were emitted in relatively low concentrations. For VOCs emitted from NMP product, the airborne concentration of styrene was the highest (633 ± 67 μg/m(3)). Leaching characteristics of metal ions from composite products were tested using acetic acid buffer solution and sulphuric acid and nitric acid solution. Then the metal concentrations in the leachates were tested by ICP-AES. The results showed that only the concentration of Cu (average = 893 mg/L; limit = 100 mg/L) in the leachate solution of the FRP using acetic acid buffer solution exceeded the standard limit. However, concentrations of other metal ions (Pb, Cd, Cr, Ba, and Ni) were within the standard limit. All the results indicated that the FRP in composite products was not a major concern in terms of environmental assessment based upon VOCs tests and leaching characteristics.

  1. PCB drill path optimization by combinatorial cuckoo search algorithm.

    PubMed

    Lim, Wei Chen Esmonde; Kanagaraj, G; Ponnambalam, S G

    2014-01-01

    Optimization of drill path can lead to significant reduction in machining time which directly improves productivity of manufacturing systems. In a batch production of a large number of items to be drilled such as printed circuit boards (PCB), the travel time of the drilling device is a significant portion of the overall manufacturing process. To increase PCB manufacturing productivity and to reduce production costs, a good option is to minimize the drill path route using an optimization algorithm. This paper reports a combinatorial cuckoo search algorithm for solving drill path optimization problem. The performance of the proposed algorithm is tested and verified with three case studies from the literature. The computational experience conducted in this research indicates that the proposed algorithm is capable of efficiently finding the optimal path for PCB holes drilling process.

  2. PCB Drill Path Optimization by Combinatorial Cuckoo Search Algorithm

    PubMed Central

    Lim, Wei Chen Esmonde; Kanagaraj, G.; Ponnambalam, S. G.

    2014-01-01

    Optimization of drill path can lead to significant reduction in machining time which directly improves productivity of manufacturing systems. In a batch production of a large number of items to be drilled such as printed circuit boards (PCB), the travel time of the drilling device is a significant portion of the overall manufacturing process. To increase PCB manufacturing productivity and to reduce production costs, a good option is to minimize the drill path route using an optimization algorithm. This paper reports a combinatorial cuckoo search algorithm for solving drill path optimization problem. The performance of the proposed algorithm is tested and verified with three case studies from the literature. The computational experience conducted in this research indicates that the proposed algorithm is capable of efficiently finding the optimal path for PCB holes drilling process. PMID:24707198

  3. Design and implementation of a multi-sensor robot system for printed circuit board insertion

    NASA Technical Reports Server (NTRS)

    Sood, Deepak; Repko, Michael C.; Kelley, Robert B.

    1989-01-01

    The design and implementation of a robot system equipped with multiple sensors are described. The robotic assembly system couples the task sequence of the robot with information from different sensors, enabling the system to handle uncertainties encountered during task execution. The target task involves the insertion of a printed circuit board into a card cage. The sensors used are an overhead three-dimensional vision system, a fingertip cross-fire sensor, and a 6-DOF force/torque sensor. The vision system is used to locate the printed circuit boards and the insertion slots. Information provided by the cross-fire sensor is used to complement the information from the vision system in order to obtain a proper grasping location on the printed circuit board. A fuzzy-logic-based system is used to interpret the forces and torques generated by the force/torque sensor during the insertion process. The repeated success of this assembly task over many experimental trials verifies the modeling and controller assumptions.

  4. A multi-stage image charge detector made from printed circuit boards.

    PubMed

    Barney, Brandon L; Daly, R Terik; Austin, Daniel E

    2013-11-01

    We present the first reported instance of an image-charge detector for charged particles in which detection elements are patterned onto printed circuit boards. In contrast to conventional techniques involving separately machined and positioned segments of metal tubing, this technique is much simpler to assemble, align, and connect to electrical wiring, with no loss in sensitivity. The performance of single-stage and 5-stage charge detectors is demonstrated using electrospray-charged, micrometer-size polystyrene spheres. Both velocity and charge of each particle are measured. Multiple detection stages--which require no extra effort to pattern or setup compared with a single stage--result in an ensemble averaging effect, improving the detection limit over what can be achieved with a single-stage detector. A comparison is made between the printed circuit board detector and a conventional tubular charge detector and found to be statistically equivalent. These results demonstrate and illustrate that devices for detection, analysis, and/or manipulation of charged particles and ions can be made using printed circuit boards rather than using separately fabricated metal electrodes.

  5. Study of Photosensitive Dry Films Absorption for Printed Circuit Boards by Photoacoustic Technique

    NASA Astrophysics Data System (ADS)

    Hernández, R.; Zaragoza, J. A. Barrientos; Jiménez-Pérez, J. L.; Orea, A. Cruz; Correa-Pacheco, Z. N.

    2017-08-01

    In this work, the study of photosensitive dry-type films by photoacoustic technique is proposed. The dry film photoresist is resistant to chemical etching for printed circuit boards such as ferric chloride, sodium persulfate or ammonium, hydrochloric acid. It is capable of faithfully reproducing circuit pattern exposed to ultraviolet light (UV) through a negative. Once recorded, the uncured portion is removed with alkaline solution. It is possible to obtain good results in surface mount circuits with tracks of 5 mm. Furthermore, the solid resin films are formed by three layers, two protective layers and a UV-sensitive optical absorption layer in the range of 325 nm to 405 nm. By means of optical absorption of UV-visible rays emitted by a low-power Xe lamp, the films transform this energy into thermal waves generated by the absorption of optical radiation and subsequently no-radiative de-excitation occurs. The photoacoustic spectroscopy is a useful technique to measure the transmittance and absorption directly. In this study, the optical absorption spectra of the three layers of photosensitive dry-type films were obtained as a function of the wavelength, in order to have a knowledge of the absorber layer and the protective layers. These analyses will give us the physical properties of the photosensitive film, which are very important in curing the dry film for applications in printed circuit boards.

  6. Laser direct imaging of high density patterns on PCB covered by photoresist

    NASA Astrophysics Data System (ADS)

    Barbucha, R.; Kocik, M.; Mizeraczyk, J.; Koziol, G.; Borecki, J.

    2007-03-01

    The increasing demands for miniaturization and better functionality of electronic components and devices have a significant effect on the requirements facing the printed circuit board (PCB) industry. PCB manufactures are driving for producing high density interconnect (HDI) boards at significantly reduced cost and reduced implementation time. The interconnection complexity of the PCB is still growing and today calls for 50/50 μm or 25/25 μm technology are real. Existing technologies are unable to offer acceptable solution. Recently the Laser Direct Imaging (LDI) technology is considered as an answer for these challenges. LDI is a process of imaging electric circuits directly on PCB without the use of a phototool or mask. The exposure of the photo-sensitive resist is carried out using a laser beam that is scanned across photoresist surface and switched on and off by means of a computer control system according to the electrical circuit pattern. Usually the laser used in the LDI generates a UV line, which is suitable to the commonly available photoresists. In this paper we present the laboratory system for Laser Direct Imaging and also the recent results on imaging the circuitry pattern on the PCB covered by a photosensitive resist.

  7. Enrichment of the metallic components from waste printed circuit boards by a mechanical separation process using a stamp mill.

    PubMed

    Yoo, Jae-Min; Jeong, Jinki; Yoo, Kyoungkeun; Lee, Jae-Chun; Kim, Wonbaek

    2009-03-01

    Printed circuit boards incorporated in most electrical and electronic equipment contain valuable metals such as Cu, Ni, Au, Ag, Pd, Fe, Sn, and Pb. In order to employ a hydrometallurgical route for the recycling of valuable metals from printed circuit boards, a mechanical pre-treatment step is needed. In this study, the metallic components from waste printed circuit boards have been enriched using a mechanical separation process. Waste printed circuit boards shredded to <10mm were milled using a stamp mill to liberate the various metallic components, and then the milled printed circuit boards were classified into fractions of <0.6, 0.6-1.2, 1.2-2.5, 2.5-5.0, and >5.0mm. The fractions of milled printed circuit boards of size <5.0mm were separated into a light fraction of mostly non-metallic components and a heavy fraction of the metallic components by gravity separation using a zig-zag classifier. The >5.0mm fraction and the heavy fraction were subjected to two-step magnetic separation. Through the first magnetic separation at 700 Gauss, 83% of the nickel and iron, based on the whole printed circuit boards, was recovered in the magnetic fraction, and 92% of the copper was recovered in the non-magnetic fraction. The cumulative recovery of nickel-iron concentrate was increased by a second magnetic separation at 3000 Gauss, but the grade of the concentrate decreased remarkably from 76% to 56%. The cumulative recovery of copper concentrate decreased, but the grade increased slightly from 71.6% to 75.4%. This study has demonstrated the feasibility of the mechanical separation process consisting of milling/size classification/gravity separation/two-step magnetic separation for enriching metallic components such as Cu, Ni, Al, and Fe from waste printed circuit boards.

  8. Enrichment of the metallic components from waste printed circuit boards by a mechanical separation process using a stamp mill

    SciTech Connect

    Yoo, Jae-Min; Jeong, Jinki; Yoo, Kyoungkeun; Lee, Jae-chun Kim, Wonbaek

    2009-03-15

    Printed circuit boards incorporated in most electrical and electronic equipment contain valuable metals such as Cu, Ni, Au, Ag, Pd, Fe, Sn, and Pb. In order to employ a hydrometallurgical route for the recycling of valuable metals from printed circuit boards, a mechanical pre-treatment step is needed. In this study, the metallic components from waste printed circuit boards have been enriched using a mechanical separation process. Waste printed circuit boards shredded to <10 mm were milled using a stamp mill to liberate the various metallic components, and then the milled printed circuit boards were classified into fractions of <0.6, 0.6-1.2, 1.2-2.5, 2.5-5.0, and >5.0 mm. The fractions of milled printed circuit boards of size <5.0 mm were separated into a light fraction of mostly non-metallic components and a heavy fraction of the metallic components by gravity separation using a zig-zag classifier. The >5.0 mm fraction and the heavy fraction were subjected to two-step magnetic separation. Through the first magnetic separation at 700 Gauss, 83% of the nickel and iron, based on the whole printed circuit boards, was recovered in the magnetic fraction, and 92% of the copper was recovered in the non-magnetic fraction. The cumulative recovery of nickel-iron concentrate was increased by a second magnetic separation at 3000 Gauss, but the grade of the concentrate decreased remarkably from 76% to 56%. The cumulative recovery of copper concentrate decreased, but the grade increased slightly from 71.6% to 75.4%. This study has demonstrated the feasibility of the mechanical separation process consisting of milling/size classification/gravity separation/two-step magnetic separation for enriching metallic components such as Cu, Ni, Al, and Fe from waste printed circuit boards.

  9. Assembling surface mounted components on ink-jet printed double sided paper circuit board.

    PubMed

    Andersson, Henrik A; Manuilskiy, Anatoliy; Haller, Stefan; Hummelgård, Magnus; Sidén, Johan; Hummelgård, Christine; Olin, Håkan; Nilsson, Hans-Erik

    2014-03-07

    Printed electronics is a rapidly developing field where many components can already be manufactured on flexible substrates by printing or by other high speed manufacturing methods. However, the functionality of even the most inexpensive microcontroller or other integrated circuit is, at the present time and for the foreseeable future, out of reach by means of fully printed components. Therefore, it is of interest to investigate hybrid printed electronics, where regular electrical components are mounted on flexible substrates to achieve high functionality at a low cost. Moreover, the use of paper as a substrate for printed electronics is of growing interest because it is an environmentally friendly and renewable material and is, additionally, the main material used for many packages in which electronics functionalities could be integrated. One of the challenges for such hybrid printed electronics is the mounting of the components and the interconnection between layers on flexible substrates with printed conductive tracks that should provide as low a resistance as possible while still being able to be used in a high speed manufacturing process. In this article, several conductive adhesives are evaluated as well as soldering for mounting surface mounted components on a paper circuit board with ink-jet printed tracks and, in addition, a double sided Arduino compatible circuit board is manufactured and programmed.

  10. Surface and Electrical Characterization of Ag/AgCl Pseudo-Reference Electrodes Manufactured with Commercially Available PCB Technologies

    PubMed Central

    Moschou, Despina; Trantidou, Tatiana; Regoutz, Anna; Carta, Daniela; Morgan, Hywel; Prodromakis, Themistoklis

    2015-01-01

    Lab-on-Chip is a technology that could potentially revolutionize medical Point-of-Care diagnostics. Considerable research effort is focused towards innovating production technologies that will make commercial upscaling financially viable. Printed circuit board manufacturing techniques offer several prospects in this field. Here, we present a novel approach to manufacturing Printed Circuit Board (PCB)-based Ag/AgCl reference electrodes, an essential component of biosensors. Our prototypes were characterized both structurally and electrically. Scanning Electron Microscopy (SEM) and X-Ray Photoelectron Spectroscopy (XPS) were employed to evaluate the electrode surface characteristics. Electrical characterization was performed to determine stability and pH dependency. Finally, we demonstrate utilization along with PCB pH sensors, as a step towards a fully integrated PCB platform, comparing performance with discrete commercial reference electrodes. PMID:26213940

  11. Recovery of copper from printed circuit boards scraps by mechanical processing and electrometallurgy.

    PubMed

    Veit, Hugo Marcelo; Bernardes, Andréa Moura; Ferreira, Jane Zoppas; Tenório, Jorge Alberto Soares; de Fraga Malfatti, Célia

    2006-10-11

    The constant growth in generation of solid wastes stimulates studies of recycling processes. The electronic scrap is part of this universe of obsolete and/or defective materials that need to be disposed of more appropriately, or then recycled. In this work, printed circuit boards, that are part of electronic scrap and are found in almost all electro-electronic equipments, were studied. Printed circuit boards were collected in obsolete or defective personal computers that are the largest source of this kind of waste. Printed circuit boards are composed of different materials such as polymers, ceramics and metals, which makes the process more difficult. However, the presence of metals, such as copper and precious metals encourage recycling studies. Also the presence of heavy metals, as Pb and Cd turns this scrap into dangerous residues. This demonstrates the need to search for solutions of this kind of residue, in order to have it disposed in a proper way, without harming the environment. At the first stage of this work, mechanical processing was used, as comminution followed by size, magnetic and electrostatic separation. By this process it was possible to obtain a concentrated fraction in metals (mainly Cu, Pb and Sn) and another fraction containing polymers and ceramics. The copper content reached more than 50% in mass in most of the conductive fractions and significant content of Pb and Sn. At the second stage, the fraction concentrated in metals was dissolved with acids and treated in an electrochemical process in order to recover the metals separately, especially copper. The results demonstrate the technical viability of recovering copper using mechanical processing followed by an electrometallurgical technique. The copper content in solution decayed quickly in all the experiments and the copper obtained by electrowinning is above 98% in most of the tests.

  12. Recovery of gold from computer circuit board scrap using aqua regia.

    PubMed

    Sheng, Peter P; Etsell, Thomas H

    2007-08-01

    Computer circuit board scrap was first treated with one part concentrated nitric acid and two parts water at 70 degrees C for 1 h. This step dissolved the base metals, thereby liberating the chips from the boards. After solid-liquid separation, the chips, intermixed with some metallic flakes and tin oxide precipitate, were mechanically crushed to liberate the base and precious metals contained within the protective plastic or ceramic chip cases. The base metals in this crushed product were dissolved by leaching again with the same type of nitric acid-water solution. The remaining solid constituents, crushed chips and resin, plus solid particles of gold, were leached with aqua regia at various times and temperatures. Gold was precipitated from the leachate with ferrous sulphate.

  13. Note: Printed circuit board based electrically triggered compact rail gap switch.

    PubMed

    Saxena, A K; Kaushik, T C; Goswami, M P; Gupta, Satish C

    2010-05-01

    An electrically triggered rail gap switch has been designed over a commercially available copper clad fiberglass sheet commonly used in making printed circuit boards for applications requiring compact design and direct integration to parallel plate transmission lines. Switch performance has been investigated in terms of its inductance, jitter, and gap closing time. With an electrode separation of 9.0 mm, it has been found to have an inductance of 6 nH, gap closing time of 5 ns, and jitter of about 4-10 ns measured at 95% of self-breakdown voltage. An application of this switch has been demonstrated as an electrically exploding foil accelerator developed over the same board and velocities up to 1.6 km/s have been achieved on Kapton flyers with diameter of 3.0 mm and thickness of 125 microm using a compact 1 microF capacitor bank.

  14. Estimation of Operating Condition of Appliances Using Circuit Current Data on Electric Distribution Boards

    NASA Astrophysics Data System (ADS)

    Iwafune, Yumiko; Ogimoto, Kazuhiko; Yagita, Yoshie

    The Energy management systems (EMS) on demand sides are expected as a method to enhance the capability of supply and demand balancing of a power system under the anticipated penetration of renewable energy generation such as Photovoltaics (PV). Elucidation of energy consumption structure in a building is one of important elements for realization of EMS and contributes to the extraction of potential energy saving. In this paper, we propose the estimation method of operating condition of household appliances using circuit current data on an electric distribution board. Circuit current data are broken down by their shape using a self-organization map method and aggregated by appliance based on customers' information of appliance possessed. Proposed method is verified using residential energy consumption measurement survey data.

  15. Recovery Act: High-Temperature Circuit Boards for use in Geothermal Well Monitoring Applications

    SciTech Connect

    Hooker, Matthew; Fabian, Paul

    2013-05-01

    The U.S. Department of Energy is leading the development of alternative energy sources that will ensure the long-term energy independence of our nation. One of the key renewable resources currently being advanced is geothermal energy. To tap into the large potential offered by generating power from the heat of the earth, and for geothermal energy to be more widely used, it will be necessary to drill deeper wells to reach the hot, dry rock located up to 10 km beneath the earth’s surface. In this instance, water will be introduced into the well to create a geothermal reservoir. A geothermal well produced in this manner is referred to as an enhanced geothermal system (EGS). EGS reservoirs are typically at depths of 3 to 10 km, and the temperatures at these depths have become a limiting factor in the application of existing downhole technologies. These high temperatures are especially problematic for electronic systems such as downhole data-logging tools, which are used to map and characterize the fractures and high-permeability regions in underground formations. Information provided by these tools is assessed so that underground formations capable of providing geothermal energy can be identified, and the subsequent drilling operations can be accurately directed to those locations. The mapping of geothermal resources involves the design and fabrication of sensor packages, including the electronic control modules, to quantify downhole conditions (300°C temperature, high pressure, seismic activity, etc.). Because of the extreme depths at which these measurements are performed, it is most desirable to perform the sensor signal processing downhole and then transmit the information to the surface. This approach necessitates the use of high-temperature electronics that can operate in the downhole environment. Downhole signal processing in EGS wells will require the development and demonstration of circuit boards that can withstand the elevated temperatures found at these

  16. Enhanced pluggable out-of-plane coupling components for printed circuit board-level optical interconnections

    NASA Astrophysics Data System (ADS)

    Van Erps, J.; Heyvaert, S.; Debaes, C.; Van Giel, B.; Hendrickx, N.; Van Daele, P.; Thienpont, H.

    2008-04-01

    We present an enhanced out-of-plane coupling component for Printed Circuit Board-level optical interconnections. Rather than using a standard 45° micro-mirror to turn the light path over 90° we introduce a curvature in the mirror profile and incorporate an extra cylindrical micro-lens for beam collimation. Both modifications enable an increase in coupling efficiency and are extensively investigated using non-sequential ray tracing simulations in combination with Matlab optimization algorithms. The resulting design is fabricated using Deep Proton Writing and experimental characterization of the geometrical properties and measured coupling efficiencies are presented.

  17. A wearable ECG acquisition system with compact planar-fashionable circuit board-based shirt.

    PubMed

    Yoo, Jerald; Yan, Long; Lee, Seulki; Kim, Hyejung; Yoo, Hoi-Jun

    2009-11-01

    A wearable electrocardiogram (ECG) acquisition system implemented with planar-fashionable circuit board (P-FCB)-based shirt is presented. The proposed system removes cumbersome wires from conventional Holter monitor system for convenience. Dry electrodes screen-printed directly on fabric enables long-term monitoring without skin irritation. The ECG monitoring shirt exploits a monitoring chip with a group of electrodes around the body, and both the electrodes and the interconnection are implemented using P-FCB to enhance wearability and to lower production cost. The characteristics of P-FCB electrode are shown, and the prototype hardware is implemented to successfully verify the proposed concept.

  18. Separation of the metallic and non-metallic fraction from printed circuit boards employing green technology.

    PubMed

    Estrada-Ruiz, R H; Flores-Campos, R; Gámez-Altamirano, H A; Velarde-Sánchez, E J

    2016-07-05

    The generation of electrical and electronic waste is increasing day by day; recycling is attractive because of the metallic fraction containing these. Nevertheless, conventional techniques are highly polluting. The comminution of the printed circuit boards followed by an inverse flotation process is a clean technique that allows one to separate the metallic fraction from the non-metallic fraction. It was found that particle size and superficial air velocity are the main variables in the separation of the different fractions. In this way an efficient separation is achieved by avoiding the environmental contamination coupled with the possible utilization of the different fractions obtained.

  19. Comparison between conventional and laser method of imaging tracks on PCB

    NASA Astrophysics Data System (ADS)

    Barbucha, R.; Kocik, M.; Mizeraczyk, J.; Kozioł, G.; Borecki, J.

    2007-02-01

    The increasing demands for miniaturization and better functionality of electronic components and devices have a significant effect on the requirements facing the printed circuit board (PCB) industry. PCB manufactures are driving for producing high density interconnect (HDI) boards at significantly reduced cost and reduced implementation time. The interconnection complexity of the PCB is still growing and today calls for 50/50 μm or 25/25 μm technology are real. Existing technologies are unable to offer acceptable solution. Recently the Laser Direct Imaging (LDI) technology is considered as an answer for these challenges. LDI is a process of imaging electric circuits directly on PCB without the use of a phototool or mask. The exposure of the photo-sensitive resist is carried out using a laser beam that is scanned across photoresist surface and switched on and off by means of a computer control system according to the electrical circuit pattern. Usually the laser used in the LDI generates a UV line, which is suitable to the commonly available photoresists. Our laboratory system for Laser Direct Imaging is designed for tracks and spaces on PCB with minimum width distance of 50/50 μm. In comparison with conventional photolithography method, this technology is much better for 50/50 μm track and spaces. In our research we used photoresist with resolution 50 μm, but in case of using laser photoresists with better resolution (e.g. 25 μm) it will be possible to image tracks in super-fine-line technology (25/25 μm). The comparison between two technology of creating mosaic pattern tracks on PCB proved that laser imaging is promising technology in high density interconnects patterns, which are widely use in multilayered PCB and similar applications.

  20. Waste-minimization assessment for a manufacturer of printed-circuit boards. Environmental research brief

    SciTech Connect

    Kirsch, F.W.; Looby, G.P.

    1991-07-01

    The U.S. Environmental Protection Agency (EPA) has funded a pilot project to assist small- and medium-size manufacturers who want to minimize their generation of hazardous waste but who lack the expertise to do so. Waste Minimization Assessment Centers (WMACs) were established at selected universities and procedures were adapted from the EPA Waste Minimization Opportunity Assessment Manual (EPA/625/7-88/003, July 1988). The WMAC team at Colorado State University inspected a plant producing printed circuit boards -- a plant that already had taken steps to control its hazardous wastes. Producing a circuit board involves many major processes and subprocesses: preparing the board; depositing copper on the board by electroless plating; applying dry film; electrolytically plating copper; electrolytically plating tin; etching and stripping; applying solder; and, perhaps, plating gold on connectors. Each of these steps produces hazardous wastes, e.g., electrolytic copper plating results in acid soap dumps, copper and tin drag-out, and sulfuric acid. The main sources of metallic contamination (copper (both dissolved and metallic), tin, lead, gold) are the rinses after scrubbing, plating, and etching. Although the greatest amount of waste can be reduced by reusing effluent from the MEMTEK (with some further treatment), the greatest dollar savings can be found by changing the dry film developer. The present brand adheres strongly to the unexposed film and requires an aggressive acid soap; a less aggressive, nonhazardous soap could be used with a less-adhering dry film developer. The Research Brief was developed by the principal investigators and EPA's Risk Reduction Engineering Laboratory, Cincinnati, OH, to announce key findings of an ongoing research project that is fully documented in a separate report of the same title available from the authors.

  1. Initial Corrosion Behavior and Mechanism of PCB-HASL in Typical Outdoor Environments in China

    NASA Astrophysics Data System (ADS)

    Ding, Kangkang; Xiao, Kui; Dong, Chaofang; Zou, Shiwen; Yi, Pan; Li, Xiaogang

    2015-11-01

    A long-term (1, 3, and 6 months) outdoor exposure test was performed for lead-free hot air solder leveling printed circuit boards (PCB-HASL) in typical environments in China and the corrosion behavior and mechanism of outdoor PCB-HASL were investigated. In a dry environment PCB-HASL corroded slightly, because of the protective effect of surface oxide films. Corrosion spread from places where dust particles were deposited or mold spores were adsorbed. Under the combined effects of humidity and contamination, large amounts of granular corrosion products with a loose structure were generated, greatly reducing the protective effect of the Sn layer. Furthermore, protection of the edges of the plates was poor, and corrosion products from these regions migrated rapidly on the FR-4 board. When a 12 V electrical bias was applied, Sn and Cu migrated simultaneously. In the electrochemical migration process the effect of humidity was much more critical than that of contamination.

  2. Fabrication and integration of micro/nano-scale optical waveguides and photonic devices for application-specific planar optical integrated circuit board

    NASA Astrophysics Data System (ADS)

    Lee, El-Hang; Lee, S. G.; O, B. H.; Park, S. G.; Kim, K. H.

    2006-02-01

    We present a review of our work on the micro/nano-scale design, fabrication and integration of optical waveguide arrays and devices for what we call application-specific "optical printed circuit boards" (O-PCBs). Generic O-PCBs are composed of an optical layer carrying basic forms of optical wires and devices and an electrical layer carrying arrays of electrical wires and devices. Application-specific O-PCBs carry optical layers that are composed of varied forms of optical wires and devices tailored to perform specific functions. In this paper, we present two examples of application specific O-PCB: One is a module for inter-chip optical interconnection application and the other is an all optical wavelength splitting triplexer module that we investigated for subscriber telecommunication application. The inter-chip optical interconnection module is to replace copper wires between the central processing units (CPUs) and memory chips in the computer system. The triplexer module is composed of an array of cascaded directional couplers to split the wavelengths for fiber-to-the-home (FTTH) subscriber system application. All these O-PCBs consist of planar circuits and arrays of polymer waveguides and devices of various dimensions and characteristics to perform the functions of transporting, switching, routing and distributing optical signals on flat modular boards. We fabricate polymer waveguide by way of thermal or ultraviolet (UV) embossing (or imprinting) technique. Theoretical calculations provide design rules for the miniaturization of the waveguide devices and for the maximization of the integration densities of the waveguides and devices to be placed on the O-PCBs.

  3. Nonlinear electromagnetic energy harvesters fabricated by rigid-flex printed circuit board technology

    NASA Astrophysics Data System (ADS)

    Chiu, Yi; Hong, Hao-Chiao; Hsu, Wei-Hung

    2015-12-01

    In this paper, a wideband electromagnetic energy harvester designed and fabricated by commercial rigid-flex PCB technology is demonstrated. The rigid FR-4 boards are used for mechanical frames and coil winding whereas the flexible polyimide film is used for mechanical springs and mass platforms. The total dimension of the device is 20 × 20 × 2 mm3. The internal coil resistance is 15 Ω. In vibration tests, nonlinearity can be observed even at 0.1 g vibration level due to the spring hardening effect. The peak frequency was increased as the vibration level increased. The effective bandwidth was increased from 6 Hz at 0.1 g to 21 Hz at 0.5 g and 27 Hz at 1 g, respectivel, due to the hysteresis effect. For a matched load and 1 g vibration at 240 Hz, the maximum output power is 24.5 nW, corresponding to a power density of 31 nW/cm3.

  4. Three-dimensionally deformable, highly stretchable, permeable, durable and washable fabric circuit boards

    PubMed Central

    Li, Qiao; Tao, Xiao Ming

    2014-01-01

    This paper reports fabric circuit boards (FCBs), a new type of circuit boards, that are three-dimensionally deformable, highly stretchable, durable and washable ideally for wearable electronic applications. Fabricated by using computerized knitting technologies at ambient dry conditions, the resultant knitted FCBs exhibit outstanding electrical stability with less than 1% relative resistance change up to 300% strain in unidirectional tensile test or 150% membrane strain in three-dimensional ball punch test, extraordinary fatigue life of more than 1 000 000 loading cycles at 20% maximum strain, and satisfactory washing capability up to 30 times. To the best of our knowledge, the performance of new FCBs has far exceeded those of previously reported metal-coated elastomeric films or other organic materials in terms of changes in electrical resistance, stretchability, fatigue life and washing capability as well as permeability. Theoretical analysis and numerical simulation illustrate that the structural conversion of knitted fabrics is attributed to the effective mitigation of strain in the conductive metal fibres, hence the outstanding mechanical and electrical properties. Those distinctive features make the FCBs particularly suitable for next-to-skin electronic devices. This paper has further demonstrated the application potential of the knitted FCBs in smart protective apparel for in situ measurement during ballistic impact. PMID:25383032

  5. Thermal verification testing of commercial printed-circuit boards for spaceflight

    NASA Technical Reports Server (NTRS)

    Foster, William M., II

    1991-01-01

    A method is discussed developed to verify commercial printed-circuit boards for a shuttle orbital flight. The Space Acceleration Measurement System Project used this method first with great success. The test sequence is based on early fault detection, desire to test the final assembly, and integration with other verification testing. A component thermal screening test is performed first to force flaws in design, workmanship, parts, processes, and materials into observable failures. Then temperature definition tests are performed that consist of infrared scanning, thermal vacuum testing, and preliminary thermal operational testing. Only the engineering unit is used for temperature definition testing, but the preliminary thermal operational testing is performed on the flight unit after the temperature range has been defined. In the sequence of testing, vibration testing is performed next, but most vibration failures cannot be detected without subsequent temperature cycling. Finally, final assembly testing is performed to simulate the shuttle flight. An abbreviated thermal screening test is performed as a check after the vibration test, and then a complete thermal operational test is performed. The final assembly test finishes up with a burn-in of 100 hours of trouble-free operation. Verification is successful when all components and final assemblies have passed each test satisfactory. This method was very successful in verifying that commercial printed-circuit boards will survive in the shuttle environment.

  6. Microwave assisted leaching and electrochemical recovery of copper from printed circuit boards of computer waste

    NASA Astrophysics Data System (ADS)

    Ivǎnuş, R. C.; ǎnuş, D., IV; Cǎlmuc, F.

    2010-06-01

    Due to the rapid technological progress, the replacement of electronic equipment is very often necessary, leading to huge amounts that end up as waste. In addition, waste electrical and electronic equipment (WEEE) contains metals of high commercial value and others that are supposed to be hazardous for the environment. Consequently, WEEE could be considered as a significant source for recovery of nonferrous metals. Among these wastes, computers appear to be distinctive, as far as further exploitation is concerned. The most ″useful″ parts of the computers are the printed circuit boards that contain many metals of interest. A study on microwave assisted electronic scrap (printed circuit boards of computer waste - PCBs) leaching was carried out with a microwave hydrothermal reactor. The leaching was conducted with thick slurries (50-100 g/L). The leaching media is a mixed solution of CuCl2 and NaCl. Preliminary electrolysis from leaching solution has investigated the feasibility of electrodeposition of copper. The results were discussed and compared with the conventional leaching method and demonstrated the potential for selective extraction of copper from PCBs.

  7. Mineralogical analysis of dust collected from typical recycling line of waste printed circuit boards.

    PubMed

    Wang, Fangfang; Zhao, Yuemin; Zhang, Tao; Duan, Chenlong; Wang, Lizhang

    2015-09-01

    As dust is one of the byproducts originating in the mechanical recycling process of waste printed circuit boards such as crushing and separating, from the viewpoints of resource reuse and environmental protection, an effective recycling method to recover valuable materials from this kind of dust is in urgent need. In this paper, detailed mineralogical analysis on the dust collected from a typical recycling line of waste printed circuit boards is investigated by coupling several analytical techniques. The results demonstrate that there are 73.1wt.% organic matters, 4.65wt.% Al, 4.55wt.% Fe, 2.67wt.% Cu and 1.06wt.% Pb in the dust, which reveals the dust is worthy of reuse and harmful to environment. The concentration ratios of Fe, Mn and Zn can reach 12.35, 12.33 and 6.67 respectively by magnetic separation. The yield of dust in each size fraction is nonuniform, while the yield of -0.75mm size fraction is up to 51.15wt.%; as the particle size decreases, the content of liberated metals and magnetic materials increase, and metals are mainly in elemental forms. The F, Cl and Br elements combing to C in the dust would make thermal treatment dangerous to the environment. Based on these results, a flowsheet to recycle the dust is proposed.

  8. Selective separation of copper over solder alloy from waste printed circuit boards leach solution.

    PubMed

    Kavousi, Maryam; Sattari, Anahita; Alamdari, Eskandar Keshavarz; Firozi, Sadegh

    2017-02-01

    The printed circuit boards (PCBs) from electronic waste are important resource, since the PCBs contain precious metals such as gold, copper, tin, silver, platinum and so forth. In addition to the economic point of view, the presence of lead turns this scrap into dangerous to environment. This study was conducted as part of the development of a novel process for selective recovery of copper over tin and lead from printed circuit boards by HBF4 leaching. In previous study, Copper with solder alloy was associated, simultaneously were leached in HBF4 solution using hydrogen peroxide as an oxidant at room temperature. The objective of this study is the separation of copper from tin and lead from Fluoroborate media using CP-150 as an extractant. The influence of organic solvent's concentration, pH, temperature and A/O phase ratio was investigated. The possible extraction mechanism and the composition of the extracted species have been determined. The separation factors for these metals using this agent are reported, while efficient methods for separation of Cu (II) from other metal ions are proposed. The treatment of leach liquor for solvent extraction of copper with CP-150 revealed that 20% CP-150 in kerosene, a 30min period of contact time, and a pH of 3 were sufficient for the extraction of Cu(II) and 99.99% copper was recovered from the leached solution. Copyright © 2016. Published by Elsevier Ltd.

  9. Selective recovery of palladium from waste printed circuit boards by a novel non-acid process.

    PubMed

    Zhang, Zhiyuan; Zhang, Fu-Shen

    2014-08-30

    An environmental benign, non-acid process was successfully developed for selective recovery of palladium from waste printed circuit boards (PCBs). In the process, palladium was firstly enriched during copper recovery procedure and dissolved in a special solution made of CuSO4 and NaCl. The dissolved palladium was then extracted by diisoamyl sulfide (S201). It was found that 99.4% of Pd(II) could be extracted from the solution under the optimum conditions (10% S201, A/O ratio 5 and 2min extraction). In the whole extraction process, the influence of base metals was negligible due to the relatively weak nucleophilic substitution of S201 with base metal irons and the strong steric hindrance of S201 molecular. Around 99.5% of the extracted Pd(II) could be stripped from S201/dodecane with 0.1mol/L NH3 after a two-stage stripping at A/O ratio of 1. The total recovery percentage of palladium was 96.9% during the dissolution-extraction-stripping process. Therefore, this study established a benign and effective process for selective recovery of palladium from waste printed circuit boards.

  10. Immobilization of Acidithiobacillus ferrooxidans on Cotton Gauze for the Bioleaching of Waste Printed Circuit Boards.

    PubMed

    Nie, Hongyan; Zhu, Nengwu; Cao, Yanlan; Xu, Zhiguo; Wu, Pingxiao

    2015-10-01

    The bioleaching parameters of metal concentrates from waste printed circuit boards by Acidithiobacillus ferrooxidans immobilized on cotton gauze in a two-step reactor were investigated in this study. The results indicated that an average ferrous iron oxidation rate of 0.54 g/(L·h) and a ferrous iron oxidation ratio of 96.90 % were obtained after 12 h at aeration rate of 1 L/min in bio-oxidation reactor. After 96 h, the highest leaching efficiency of copper reached 91.68 % under the conditions of the content of the metal powder 12 g/L, the retention time 6 h, and the aeration rate 1 L/min. The bioleaching efficiency of copper could be above 91.12 % under repeated continuous batch operation. Meanwhile, 95.32 % of zinc, 90.32 % of magnesium, 86.31 % of aluminum, and 59.07 % of nickel were extracted after 96 h. All the findings suggested that the recovery of metal concentrates from waste printed circuit boards via immobilization of A. ferrooxidans on cotton gauze was feasible.

  11. Degradation of organic pollutants by Ag, Cu and Sn doped waste non-metallic printed circuit boards.

    PubMed

    Ramaswamy, Kadari; Radha, Velchuri; Malathi, M; Vithal, Muga; Munirathnam, Nagegownivari R

    2017-02-01

    The disposal and reuse of waste printed circuit boards have been the major global concerns. Printed circuit boards, a form of Electronic waste (hereafter e-waste), have been chemically processed, doped with Ag(+), Cu(2+) and Sn(2+), and used as visible light photocatalysts against the degradation of methylene blue and methyl violet. The elemental analyses of pristine and metal doped printed circuit board were obtained using energy dispersive X-ray fluorescence (EDXRF) spectra and inductively coupled plasma optical emission spectroscopy (ICP-OES). The morphology of parent and doped printed circuit board was obtained from scanning electron microscopy (SEM) measurements. The photocatalytic activity of parent and metal doped samples was carried out for the decomposition of organic pollutants, methylene blue and methyl violet, under visible light irradiation. Metal doped waste printed circuit boards (WPCBs) have shown higher photocatalytic activity against the degradation of methyl violet and methylene blue under visible light irradiation. Scavenger experiments were performed to identify the reactive intermediates responsible for the degradation of methylene blue and methyl violet. The reactive species responsible for the degradation of MV and MB were found to be holes and hydroxyl radicals. A possible mechanism of degradation of methylene blue and methyl violet is given. The stability and reusability of the catalysts are also investigated.

  12. Assessment of circuit board surface finishes for electronic assembly with lead-free solders

    SciTech Connect

    Ray, U.; Artaki, I.; Finley, D.W.; Wenger, G.M.; Pan, T.; Blair, H.D.; Nicholson, J.M.; Vianco, P.T.

    1996-10-01

    The suitability of various metallic printed wiring board surface finishes was assessed for new technology applications that incorporate assembly with Lead-free solders. The manufacture of a lead-free product necessitates elimination of lead (Pb) from the solder, the circuit board as well as the component lead termination. It is critical however for the selected interconnect Pb-free solder and the corresponding printed wiring board (PWB) and component lead finishes to be mutually compatible. Baseline compatibility of select Pb-free solders with Pb containing PWB surface finish and components was assessed. This was followed by examining the compatibility of the commercially available CASTIN{trademark} (SnAgCuSb) Pb-free solder with a series of PWB metallic finishes: Ni/Au, Ni/Pd, and Pd/Cu. The compatibility was assessed with respect to assembly performance, solder joint integrity and long term attachment reliability. Solder joint integrity and mechanical behavior of representative 50 mil pitch 20I/O SOICs was determined before and after thermal stress. Mechanical pull test studies demonstrated that the strength of SnAgCuSb solder interconnections is notably greater than that of SnPb interconnections.

  13. Waveguide and packaging technology for optical backplanes and hybrid electrical-optical circuit boards

    NASA Astrophysics Data System (ADS)

    Schröder, H.; Bauer, J.; Ebling, F.; Franke, M.; Beier, A.; Demmer, P.; Süllau, W.; Kostelnik, J.; Mödinger, R.; Pfeiffer, K.; Ostrzinski, U.; Griese, E.

    2006-02-01

    Due to ever-faster processor clock speeds, there is a rising need for increased bandwidth to transfer large amounts of data, noise-free, within computer and telecommunications systems. A related requirement is the demand for high bit-rate, short-haul links. Here, optical transmission paths are a viable alternative to high-frequency electrical interconnections, whereby layers with integrated waveguides are particularly suitable. The reasons for this include that a higher connection density can be achieved and the power dissipation, as well as interference from electromagnetic radiation, are significantly lower. The article presents general considerations and the results of research conducted by the German BMBF Project NeGIT, into the manufacture of circuit boards with embedded polymer optical waveguides. The electrical-optical boards were fabricated using precise photolithographic processes and standard lamination methods. They possess the thermal stability necessary for manufacturing processes and operational conditions, in terms of both bond strength and the stability of the optical properties. As part of this project, a design of an optical coupling in the daughter card and board backplane interfaces was developed and is presented as the centerpiece of this study.

  14. Toward environmentally-benign utilization of nonmetallic fraction of waste printed circuit boards as modifier and precursor

    SciTech Connect

    Hadi, Pejman; Ning, Chao; Ouyang, Weiyi; Xu, Meng; Lin, Carol S.K.; McKay, Gordon

    2015-01-15

    Highlights: • Environmental impacts of electronic waste and specifically waste printed circuit boards. • Review of the recycling techniques of waste printed circuit boards. • Advantages of physico-mechanical recycling techniques over chemical methods. • Utilization of nonmetallic fraction of waste printed circuit boards as modifier/filler. • Recent advances in the use of nonmetallic fraction of waste printed circuit boards as precursor. - Abstract: Electronic waste, including printed circuit boards, is growing at an alarming rate due to the accelerated technological progress and the shorter lifespan of the electronic equipment. In the past decades, due to the lack of proper economic and environmentally-benign recycling technologies, a major fraction of e-waste generated was either destined to landfills or incinerated with the sole intention of its disposal disregarding the toxic nature of this waste. Recently, with the increasing public awareness over their environment and health issues and with the enaction of more stringent regulations, environmentally-benign recycling has been driven to be an alternative option partially replacing the traditional eco-unfriendly disposal methods. One of the most favorable green technologies has been the mechanical separation of the metallic and nonmetallic fraction of the waste printed circuit boards. Although metallic fraction, as the most profitable component, is used to generate the revenue of the separation process, the nonmetallic fraction (NMF) has been left isolated. Herein, the recent developments in the application of NMF have been comprehensively reviewed and an eco-friendly emerging usage of NMF as a value-added material for sustainable remediation has been introduced.

  15. Optimizing the operating parameters of corona electrostatic separation for recycling waste scraped printed circuit boards by computer simulation of electric field.

    PubMed

    Li, Jia; Lu, Hongzhou; Liu, Shushu; Xu, Zhenming

    2008-05-01

    The printed circuit board (PCB) has a metal content of nearly 28% metal, including an abundance of nonferrous metals such as copper, lead, and tin. The purity of precious metals in PCBs is more than 10 times that of rich-content minerals. Therefore, the recycling of PCBs is an important subject, not only from the viewpoint of waste treatment, but also with respect to the recovery of valuable materials. Compared with traditional process the corona electrostatic separation (CES) had no waste water or gas during the process and it had high productivity with a low-energy cost. In this paper, the roll-type corona electrostatic separator was used to separate metals and nonmetals from scraped waste PCBs. The software MATLAB was used to simulate the distribution of electric field in separating space. It was found that, the variations of parameters of electrodes and applied voltages directly influenced the distribution of electric field. Through the correlation of simulated and experimental results, the good separation results were got under the optimized operating parameter: U=20-30 kV, L=L(1)=L(2)=0.21 m, R(1)=0.114, R(2)=0.019 m, theta(1)=20 degrees and theta(2)=60 degrees .

  16. Galvanic corrosion of Cu coupled to Au on a print circuit board; Effects of pretreatment solution and etchant concentration in organic solderability preservatives soft etching solution

    NASA Astrophysics Data System (ADS)

    Oh, SeKwon; Kim, YoungJun; Shon, MinYoung; Kwon, HyukSang

    2016-09-01

    In present study, we quantitatively define the galvanic corrosion phenomenon of Cu electrically coupled to Au on Print Circuit Board in Organic Solderability Preservatives (OSP) pretreatment (pickling and soft etching) solutions. As a result of polarization and ZRA test, galvanic corrosion rate of Cu in soft etching solution was about 3000 times higher than that of pickling solution. The oxone in OSP soft etching solution was acted as strong oxidant for Cu on PCB substrate. And the galvanic corrosion of Cu in OSP soft etching solution was examined with the change of etchants (oxone (KHSO5), sulfuric acid (H2SO4)) concentration. The galvanic corrosion rate of Cu was increased by the increase of the oxone and sulfuric acid concentrations, which lead to the increase of cathodic reactant such as HSO 5 - and H+ ions. And the degree of galvanic corrosion rate of Cu (Δisoft etching = icouple, (Cu-Au) - icorr, Cu) decreased with the decrease of the oxone and sulfuric acid concentrations.

  17. Optical waveguides and structures for short haul optical communication channels within printed circuit boards

    NASA Astrophysics Data System (ADS)

    Riegel, Nicholas J.

    Optical waveguides have shown promising results for use within printed circuit boards. These optical waveguides have higher bandwidth than traditional copper transmission systems and are immune to electromagnetic interference. Design parameters for these optical waveguides are needed to ensure an optimal link budget. Modeling and simulation methods are used to determine the optimal design parameters needed in designing the waveguides. As a result, optical structures necessary for incorporating optical waveguides into printed circuit boards are designed and optimized. Embedded siloxane polymer waveguides are investigated for their use in optical printed circuit boards. This material was chosen because it has low absorption, high temperature stability, and can be deposited using common processing techniques. Two sizes of waveguides are investigated, 50 mum multimode and 4 - 9 mum single mode waveguides. A beam propagation method is developed for simulating the multimode and single mode waveguide parameters. The attenuation of simulated multimode waveguides are able to match the attenuation of fabricated waveguides with a root mean square error of 0.192 dB. Using the same process as the multimode waveguides, parameters needed to ensure a low link loss are found for single mode waveguides including maximum size, minimum cladding thickness, minimum waveguide separation, and minimum bend radius. To couple light out-of-plane to a transmitter or receiver, a structure such as a vertical interconnect assembly (VIA) is required. For multimode waveguides the optimal placement of a total internal reflection mirror can be found without prior knowledge of the waveguide length. The optimal placement is found to be either 60 microm or 150 microm away from the end of the waveguide depending on which metric a designer wants to optimize the average output power, the output power variance, or the maximum possible power loss. For single mode waveguides a volume grating coupler is

  18. Infrared Thermography as Applied to Thermal Testing of Power Systems Circuit Boards.

    NASA Astrophysics Data System (ADS)

    Miles, Jonathan James

    All operational electronic equipment dissipates some amount of energy in the form of infrared radiation. Faulty electronic components on a printed circuit board can be categorized as hard (functional) or soft (latent functional). Hard faults are those which are detected during a conventional manufacturing electronic test process. Soft failures, in contrast, are those which are undetectable through conventional testing, but which manifest themselves after a product has been placed into service. Such field defective modules ultimately result in operational failure and subsequently enter a manufacturer's costly repair process. While thermal imaging systems are being used increasingly in the electronic equipment industry as a product-testing tool, applications have primarily been limited to product design or repair processes, with minimal use in a volume manufacturing environment. Use of thermal imaging systems in such an environment has mostly been limited to low-volume products or random screening of high-volume products. Thermal measurements taken in a manufacturing environment are often taken manually, thus defeating their capability of rapid data acquisition and constraining their full potential in a high-volume manufacturing process. Integration of a thermal measurement system with automated testing equipment is essential for optimal use of expensive infrared measurement tools in a high-volume manufacturing environment. However, such a marriage presents problems with respect to both existing manufacturing test processes and infrared measurement techniques. Methods are presented in this dissertation to test automatically for latent faults, those which elude detection during conventional electronic testing, on printed circuit boards. These methods are intended for implementation in a volume manufacturing environment and involve the application of infrared imaging tools. Successful incorporation of infrared testing into existing test processes requires that: PASS

  19. Four-Channel PC/104 MIL-STD-1553 Circuit Board

    NASA Technical Reports Server (NTRS)

    Cox, Gary L.

    2004-01-01

    The mini bus interface card (miniBIC) is the first four-channel electronic circuit board that conforms to MIL-STD-1553 and to the electrical-footprint portion of PC/104. [MIL-STD-1553 is a military standard that encompasses a method of communication and electrical- interface requirements for digital electronic subsystems connected to a data bus. PC/104 is an industry standard for compact, stackable modules that are fully compatible (in architecture, hardware, and software) with personal-computer data- and power-bus circuitry.] Prior to the development of the miniBIC, only one- and two-channel PC/104 MIL-STD-1553 boards were available. To obtain four channels, it was necessary to include at least two boards in a PC/104 stack. In comparison with such a two-board stack, the miniBIC takes up less space, consumes less power, and is more reliable. In addition, the miniBIC includes 32 digital input/output channels. The miniBIC (see figure) contains four MIL-STD-1553B hybrid integrated circuits (ICs), four transformers, a field-programmable gate array (FPGA), and an Industry Standard Architecture (ISA) interface. Each hybrid IC includes a MILSTD-1553 dual transceiver, memory-management circuitry, processor interface logic circuitry, and 64Kx16 bits of shared static random access memory. The memory is used to configure message and data blocks. In addition, 23 16-bit registers are available for (1) configuring the hybrid IC for, and starting it in, various modes of operation; (2) reading the status of the functionality of the hybrid IC; and (3) resetting the hybrid IC to a known state. The miniBIC can operate as a remote terminal, bus controller, or bus monitor. The FPGA provides the chip-select and data-strobe signals needed for operation of the hybrid ICs. The FPGA also receives interruption signals and forwards them to the ISA bus. The ISA interface connects the address, data, and control interfaces of the hybrid ICs to the ISA backplane. Each channel is, in effect, a MIL

  20. EMC in power electronics and PCB design

    NASA Astrophysics Data System (ADS)

    Zhu, Chentian

    This dissertation consists of two parts. Part I is about Electromagnetic Compatibility (EMC) in power electronics and part II is about the Maximum Radiated Electromagnetic Emissions Calculator (MREMC), which is a software tool for EMC in printed circuit board (PCB) design. Switched-mode power converters can be significant sources of electromagnetic fields that interfere with the proper operation of nearby circuits or distant radio receivers. Part I of this dissertation provides comprehensive and organized information on the latest EMC developments in power converters. It describes and evaluates different technologies to ensure that power converters meet electromagnetic compatibility requirements. Chapters 2 and 3 describe EMC noise sources and coupling mechanisms in power converters. Chapter 4 reviews the measurements used to characterize and troubleshoot EMC problems. Chapters 5 -- 8 cover passive filter solutions, active filter solutions, noise cancellation methods and reduced-noise driving schemes. Part II describes the methods used, calculations made, and implementation details of the MREMC, which is a software tool that allows the user to calculate the maximum possible radiated emissions that could occur due to specific source geometries on a PCB. Chapters 9 -- 13 covers the I/O coupling EMI algorithm, Common-mode EMI algorithm, Power Bus EMI algorithm and Differential-Mode EMI algorithm used in the MREMC.

  1. The high speed low noise multi-data processing signal process circuit research of remote sensing

    NASA Astrophysics Data System (ADS)

    Su, Lei; Jiang, Haibin; Dong, Wang

    2013-08-01

    The high speed, low noise and integration characteristic are the main technology and the main development directions on the signal process circuit of the image sensor, especially in high resolution remote sensing. With these developments, the high noise limiting circuits, high speed data transfer system and the integrated design of the signal process circuit become more and more important. Therefore the requirement of the circuit system simulation is more and more important during the system design and PCB board design process. A CCD signal process circuit system which has the high speed, low noise and several selectable operate modes function was designed and certificated in this paper, during the CCD signal process circuit system design, simulation was made which include the signal integrity and the power integrity. The important devices such as FPGA and the DDR2 device were simulated, using the power integrity simulation the sensitive power planes of the FPGA on the PCB was modified to make the circuit operate more stabilize on a higher frequency. The main clock path and the high speed data path of the PCB board were simulated with the signal integrity. All the simulation works make the signal process circuit system's image's SNR value get higher and make the circuit system could operate well on higher frequency. In the board testing process, the PCB time diagrams were listed on the testing chapter and the wave's parameter meets the request. The real time diagram and the simulated result of the PCB board was listed respectively. The CCD signal process circuit system's images' SNR (Signal Noise Ratio) value, the 14bit AFE slew rate and the data transfer frequency is listed in the paper respective.

  2. PCB-Based Break-Out Box

    NASA Technical Reports Server (NTRS)

    Lee, Jason H.

    2011-01-01

    Break-out boxes (BOBs) are necessary for all electrical integration/cable checkouts and troubleshooting. Because the price of a BOB is high, and no work can be done without one, often the procedure stops, simply waiting for a BOB. A less expensive BOB would take less time in the integration, testing, and troubleshooting process. The PCB-based BOB works and looks the same as a standard JPL BOB, called Gold Boxes. The only differences between the old BOB and the new PCB-based BOB is that the new one has 80 percent of its circuitry in a printed circuit board. This process reduces the time for fabrication, thus making the BOBs less expensive. Moreover, because of its unique design, the new BOBs can be easily assembled and fixed. About 80 percent of the new PCB-based BOB is in a $22 (at the time of this reporting) custom-designed, yet commercially available PCB. This device has been used successfully to verify that BOB cables were properly made. Also, upon completion, the BOB was beeped out via a multimeter to ensure that all sockets on the connectors were properly connected to the respective banana jack. When compared to the Gold Box BOBs, the new BOB has many advantages. It is much more cost efficient, it delivers equal usability at substantially lower cost of the BOB, and the Gold Box is much heavier when compared to the new BOB. The new BOB is also a bit longer and much more versatile in that connectors are easily changeable and if a banana jack is broken, it can be replaced instead of throwing away an entire BOB.

  3. Development of a flexible circuit board for low-background experiments

    NASA Astrophysics Data System (ADS)

    Poon, Alan; Barton, Paul; Dhar, Ankur; Larsen, Joern; Loach, James

    2017-01-01

    Future underground rare-event search experiments, such as neutrinoless double-beta decay searches, have stringent requirements for the radiopurity of materials placed near the active detector medium. Parylene is a polymer that has a high chemical purity and the vapor deposition process by which it is laid down tends to purify it further. In this talk the technique to fabricate a low-mass, flexible circuit board, with conductive traces photoligthographically patterned on a parylene substrate, is discussed. The performance of a proof-of-principle temperature sensor is presented. This work was supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-AC02-05CH11231 and by the Shanghai Key Lab for Particle Physics and Cosmology (SKLPPC), Grant No. 15DZ2272100.

  4. Application of Printed Circuit Board Technology to FT-ICR MS Analyzer Cell Construction and Prototyping

    SciTech Connect

    Leach, Franklin E.; Norheim, Randolph V.; Anderson, Gordon A.; Pasa-Tolic, Ljiljana

    2014-12-01

    Although Fourier transform ion cyclotron resonance mass spectrometry (FT-ICRMS) remains themass spectrometry platform that provides the highest levels of performance for mass accuracy and resolving power, there is room for improvement in analyzer cell design as the ideal quadrupolar trapping potential has yet to be generated for a broadband MS experiment. To this end, analyzer cell designs have improved since the field’s inception, yet few research groups participate in this area because of the high cost of instrumentation efforts. As a step towards reducing this barrier to participation and allowing for more designs to be physically tested, we introduce a method of FT-ICR analyzer cell prototyping utilizing printed circuit boards at modest vacuum conditions. This method allows for inexpensive devices to be readily fabricated and tested over short intervals and should open the field to laboratories lacking or unable to access high performance machine shop facilities because of the required financial investment.

  5. Quadrupole gradient coil design and optimization: a printed circuit board approach.

    PubMed

    Chu, K; Rutt, B K

    1994-06-01

    Three different dual-axis quadrupole gradient coils for quantitative high resolution MR imaging of small animals, phantoms and specimens were designed and built using printed circuit board technology. Numerical optimization of the conductor positions was used to increase the volume of 0.4% gradient uniformity by up to a factor of four. In one coil, the volume of 5% gradient uniformity occupied 88% and 83% of the overall diameter and length of the coil, respectively. A systematic error of 0.5% in the wire placement was shown to cause a reduction in the volume of 0.4% gradient uniformity by a factor of two, though the region of 5% gradient uniformity was not significantly affected. Heat transfer calculations were used to determine maximum peak and root-mean-squared currents that could safely be applied to the coils.

  6. Application of printed circuit board technology to FT-ICR MS analyzer cell construction and prototyping.

    PubMed

    Leach, Franklin E; Norheim, Randolph; Anderson, Gordon; Pasa-Tolic, Ljiljana

    2014-12-01

    Although Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) remains the mass spectrometry platform that provides the highest levels of performance for mass accuracy and resolving power, there is room for improvement in analyzer cell design as the ideal quadrupolar trapping potential has yet to be generated for a broadband MS experiment. To this end, analyzer cell designs have improved since the field's inception, yet few research groups participate in this area because of the high cost of instrumentation efforts. As a step towards reducing this barrier to participation and allowing for more designs to be physically tested, we introduce a method of FT-ICR analyzer cell prototyping utilizing printed circuit boards at modest vacuum conditions. This method allows for inexpensive devices to be readily fabricated and tested over short intervals and should open the field to laboratories lacking or unable to access high performance machine shop facilities because of the required financial investment.

  7. Design of a smart ECG garment based on conductive textile electrode and flexible printed circuit board.

    PubMed

    Cai, Zhipeng; Luo, Kan; Liu, Chengyu; Li, Jianqing

    2017-08-09

    A smart electrocardiogram (ECG) garment system was designed for continuous, non-invasive and comfortable ECG monitoring, which mainly consists of four components: Conductive textile electrode, garment, flexible printed circuit board (FPCB)-based ECG processing module and android application program. Conductive textile electrode and FPCB-based ECG processing module (6.8 g, 55 mm × 53 mm × 5 mm) are identified as two key techniques to improve the system's comfort and flexibility. Preliminary experimental results verified that the textile electrodes with circle shape, 40 mm size in diameter, and 5 mm thickness sponge are best suited for the long-term ECG monitoring application. The tests on the whole system confirmed that the designed smart garment can obtain long-term ECG recordings with high signal quality.

  8. Bioleaching waste printed circuit boards by Acidithiobacillus ferrooxidans and its kinetics aspect.

    PubMed

    Yang, Yuankun; Chen, Shu; Li, Shicheng; Chen, Mengjun; Chen, Haiyan; Liu, Bijun

    2014-03-10

    In this paper, H(+) consumption and metal recovery, during the process of bioleaching waste printed circuit boards (WPCBs) by Acidithiobacillus ferrooxidans (A. ferrooxidans), were discussed in detail. When the WPCBs concentration was 15g/L, Cu (96.8%), Zn (83.8%), and Al (75.4%) were recovered after 72h by A. ferrooxidans. Experimental results indicated that metal recovery rate was significantly influenced by acid. Based on experimental results, the kinetics of the H(+) consumption and metal recovery on bioleaching WPCBs were represented by reaction kinetic equations. The kinetic of H(+) consumption could be described by the second-order kinetic model. The metal recovery belongs to the second-order model with adding acid, which was changed to the shrinking core model with precipitate production. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Waste minimization study for a printed circuit board manufacturing facility in Taiwan

    SciTech Connect

    Chiu, Shen-yann; Huang, Hann S.; Peters, R.W.; Tsai, S.Y. ); Tsai, Wen-Tien; Shieh, Shih-Shien; Hsieh, Te-Yuan; Hwang, Li-Shyong ); Liu, Solo; Peng, Chien-Tang ); Wu, Min H. )

    1990-01-01

    This paper presents a demonstration of industrial waste minimization sponsored by the Environmental Protection Administration, Taiwan, Republic of China. Waste reduction opportunities are identified and evaluated for a printed circuit board manufacturing facility in Taiwan. Plant audits were conducted on various processes, such as deburring, alkaline etching, black oxidation, desmearing, electroless copper, and copper and tin/lead plating. Specific areas in which the wastes could be minimized, such as reducing the amount of dragout and rinse water requirements in the plating and etchant lines, and on-site treatment and reuse of spent bath solutions were identified, assessed, and implemented. Jar tests on the wastewater were performed, and the results were used to improve the efficiency of the wastewater treatment plant for removal of heavy metals and reduction of sludge generation. In addition, administrative controls of hazardous wastes designed to reduce associated health and environmental hazards were recommended. 4 figs., 9 tabs.

  10. Ductile electroless Ni-P coating onto flexible printed circuit board

    NASA Astrophysics Data System (ADS)

    Wang, Wenchang; Zhang, Weiwei; Wang, Yurong; Mitsuzak, Naotoshi; Chen, Zhidong

    2016-03-01

    In this study, a ductile electroless Ni-P coating on the flexible printed circuit board (FPCB) was prepared in an acidic nickel plating bath. The addition of dipropylamine (DPA) in electroless plating not only improves the ductility of the Ni-P coating, but also enhances the corrosion resistance. The further analysis reveals that the ductility improvement and enhancement of corrosion resistance for the Ni-P coating may be due to the fact that the addition of DPA significantly refines the volume of columnar nodule and reduce the porosity, thus leading to the released internal stress. In addition, it was found that the nodule within the Ni-P coating grew into a columnar structure, which may be also contribute to the improvement of ductility.

  11. Layer modeling of zinc removal from metallic mixture of waste printed circuit boards by vacuum distillation.

    PubMed

    Gao, Yujie; Li, Xingang; Ding, Hui

    2015-08-01

    A layer model was established to elucidate the mechanism of zinc removal from the metallic mixture of waste printed circuit boards by vacuum distillation. The removal process was optimized by response surface methodology, and the optimum operating conditions were the chamber pressure of 0.1Pa, heating temperature of 923K, heating time of 60.0min, particle size of 70 mesh (0.212mm) and initial mass of 5.25g. Evaporation efficiency of zinc, the response variable, was 99.79%, which indicates that the zinc can be efficiently removed. Based on the experimental results, a mathematical model, which bears on layer structure, evaporation, mass transfer and condensation, interprets the mechanism of the variable effects. Especially, in order to reveal blocking effect on the zinc removal, the Blake-Kozeny-Burke-Plummer equation was introduced into the mass transfer process. The layer model can be applied to a wider range of metal removal by vacuum distillation.

  12. Characteristics and crosstalk of optical waveguides fabricated in polymethyl methacrylate polymer circuit board.

    PubMed

    Hamid, Hanan H; Rüter, Christian E; Thiel, David V; Fickenscher, Thomas

    2016-11-10

    Electro-optical circuit boards should provide simple and cost-effective coupling techniques and crosstalk levels of less than -30  dB. A dicing saw was used to create waveguide grooves with a surface roughness of less than 183 nm in a 1.6-mm-thick polymethyl methacrylate polymer (PMMA) substrate. The buried optical waveguides were made from SU-8 in a PMMA substrate covered with a 1-mm PMMA sheet. The propagation loss for a 500  μm×570  μm straight waveguide was 0.9 dB/cm at 1310 nm. The coupling between parallel waveguides was measured at separation distances from 45 to 595 μm. The crosstalk was less than -40  dB for 65-mm-long waveguides. This fabrication method shows potential for dense optical interconnects with very low crosstalk.

  13. New technology for recovering residual metals from nonmetallic fractions of waste printed circuit boards.

    PubMed

    Zhang, Guangwen; He, Yaqun; Wang, Haifeng; Zhang, Tao; Wang, Shuai; Yang, Xing; Xia, Wencheng

    2017-06-01

    Recycling of waste printed circuit boards is important for environmental protection and sustainable resource utilization. Corona electrostatic separation has been widely used to recycle metals from waste printed circuit boards, but it has poor separation efficiency for finer sized fractions. In this study, a new process of vibrated gas-solid fluidized bed was used to recycle residual metals from nonmetallic fractions, which were treated using the corona electrostatic separation technology. The effects of three main parameters, i.e., vibration frequency, superficial air flow velocity, and fluidizing time on gravity segregation, were investigated using a vibrating gas-solid fluidized bed. Each size fraction had its own optimum parameters. Corresponding to their optimal segregation performance, the products from each experiment were analyzed using an X-ray fluorescence (XRF) and a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS). From the results, it can be seen that the metal recoveries of -1+0.5mm, -0.5+0.25mm, and -0.25mm size fractions were 86.39%, 82.22% and 76.63%, respectively. After separation, each metal content in the -1+0.5 or -0.5+0.25mm size fraction reduced to 1% or less, while the Fe and Cu contents are up to 2.57% and 1.50%, respectively, in the -0.25mm size fraction. Images of the nonmetallic fractions with a size of -0.25mm indicated that a considerable amount of clavate glass fibers existed in these nonmetallic fractions, which may explain why fine particles had the poorest segregation performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Effect of embedded printed circuit board (PCB) sensors on the mechanical behavior of glass fiber-reinforced polymer (GFRP) structures

    NASA Astrophysics Data System (ADS)

    Javdanitehran, M.; Hoffmann, R.; Groh, J.; Vossiek, M.; Ziegmann, G.

    2016-06-01

    The embedding of dielectric chipless sensors for cure monitoring into fiber-reinforced thermosets allows for monitoring and controlling the curing process and consequently higher quality in production. The embedded sensors remain after the processing in the structure. This affects the integrity of the composite structure locally. In order to investigate these effects on the mechanical behavior of the glass fiber-reinforced polymer (GFRP), sensors made on special low loss substrates are integrated into laminates with different lay-ups and thicknesses using vacuum assisted resin transfer molding (VARTM) method. In a parametric study the size of the sensor is varied to observe its influence on the strength and the stiffness of the laminates according to its lay-up and thickness. The size and orientation of the resin rich areas near sensors as well as the distortion in load bearing area as the consequences of the introduction of the sensors are investigated in conjunction with the strength of the structure. An empirical model is proposed by the authors which involves the previously mentioned factors and is used as a rapid tool for the prediction of the changes in bending and tensile strength of simple structures with embedded sensors. The methodology for model’s calibration as well as the validation of the model against the experimental data of different laminates with distinct lay-ups and thicknesses are presented in this work. Mechanical tests under tensile and bending loading indicate that the reduction of the structure’s strength due to sensor integration can be attributed to the size and the orientation of rich resin zones and depends over and above on the size of distorted load bearing area. Depending on the sensor’s elastic modulus the stiffness of the structure may vary through the introduction of a sensor.

  15. An electrical model of VCSEL as optical transmitter for optical printed circuit board

    NASA Astrophysics Data System (ADS)

    Kim, Do-Kyoon; Yoon, Young-Seol; Choi, Jin-Ho; Kim, Kyung-Min; Choi, Young-Wan; Lee, Seok

    2005-03-01

    Optical interconnection is recent issue for high-speed data transmission. The limitation of high-speed electrical data transmission is caused by impedance mismatching, electric field coupling, microwave loss, and different length of the electrical signal lines. To overcome these limitations, the electrical signal in the current electrical system has to be changed by the optical signal. The most suitable optical source in the OPCB (Optical Printed Circuit Board) is VCSEL (Vertical Cavity Surface Emitting Lasers) that is low-priced and has the characteristic of vertical surface emitting. In this paper, we propose an electrical model of the VCSEL as E/O converting devices for the OPCB. The equivalent circuit of the VCSEL based on the rate equations includes carrier dynamics and material properties. The rate equation parameters are obtained by full analysis based on rate equation and experiment results. The electrical model of the VCSEL has the series resistance determined by I-V characteristic curve, and the parallel capacitance by the parasitic response of the VCSEL chip. The bandwidth of the optical interconnection is analyzed considering those parameters. We design and fabricate the optical transmitter for OPCB considering proposed electrical model of VCSEL.

  16. AC properties of low-pass RC filters embedded in printed circuit boards

    NASA Astrophysics Data System (ADS)

    Winiarski, Paweł; Kłossowicz, Adam; Steplewski, Wojciech; Borecki, Janusz; Nitsch, Karol; Dziedzic, Andrzej

    2013-07-01

    Impedance Spectroscopy (IS) is a widely used measurement technique for determining the characteristics of a variety of materials and systems. Analysis of object's AC-response can allow determine of different electrical properties due to its structure. IS can also be used to study electronic components such as gas and humidity sensors, thermistors, varistors, capacitors or resistors. The resulting impedance spectrum can be approximated by electrical equivalent circuit. However, It is difficult to find papers dedicated to the electronic systems investigated by IS method. For this reason authors analyzed properties of RC low-pass filters embedded in printed circuit boards using IS technique. These four-contact structures were made of special Ohmega/FaradFlex® composite material. It consists of a resistive/capacitive core containing OhmegaPly RCM layer (resistive NiP alloy) laminated to FaradFlex dielectric of Oak-Mitsui company. Analysis of the measurements results using impedance spectroscopy allowed a more precise determination of the filter parameters than an analysis using standard method based on ideal components. Additionally selected filters were subjected to one of the aging process (thermal aging or thermal-humidity exposure), and found that this results in a frequency shift of the filter.

  17. Separation and recovery of fine particles from waste circuit boards using an inflatable tapered diameter separation bed.

    PubMed

    Duan, Chenlong; Sheng, Cheng; Wu, Lingling; Zhao, Yuemin; He, Jinfeng; Zhou, Enhui

    2014-01-01

    Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (-0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed's fluid flow field. For 0.5-0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25-0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (-0.125 mm), metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution.

  18. Separation and Recovery of Fine Particles from Waste Circuit Boards Using an Inflatable Tapered Diameter Separation Bed

    PubMed Central

    Sheng, Cheng; Wu, Lingling; Zhao, Yuemin; He, Jinfeng; Zhou, Enhui

    2014-01-01

    Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (−0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed's fluid flow field. For 0.5–0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25–0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (−0.125 mm), metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution. PMID:25379546

  19. Treatment of Wastewater from Electroplating, Metal Finishing and Printed Circuit Board Manufacturing. Operation of Wastewater Treatment Plants Volume 4.

    ERIC Educational Resources Information Center

    California State Univ., Sacramento. Dept. of Civil Engineering.

    One of four manuals dealing with the operation of wastewater plants, this document was designed to address the treatment of wastewater from electroplating, metal finishing, and printed circuit board manufacturing. It emphasizes how to operate and maintain facilities which neutralize acidic and basic waters; treat waters containing metals; destroy…

  20. Treatment of Wastewater from Electroplating, Metal Finishing and Printed Circuit Board Manufacturing. Operation of Wastewater Treatment Plants Volume 4.

    ERIC Educational Resources Information Center

    California State Univ., Sacramento. Dept. of Civil Engineering.

    One of four manuals dealing with the operation of wastewater plants, this document was designed to address the treatment of wastewater from electroplating, metal finishing, and printed circuit board manufacturing. It emphasizes how to operate and maintain facilities which neutralize acidic and basic waters; treat waters containing metals; destroy…

  1. Maze solving automatons for self-healing of open interconnects: Modular add-on for circuit boards

    SciTech Connect

    Nair, Aswathi; Raghunandan, Karthik; Yaswant, Vaddi; Sambandan, Sanjiv E-mail: ssanjiv@isu.iisc.ernet.in; Pillai, Sreelal S.

    2015-03-23

    We present the circuit board integration of a self-healing mechanism to repair open faults. The electric field driven mechanism physically restores fractured interconnects in electronic circuits and has the ability to solve mazes. The repair is performed by conductive particles dispersed in an insulating fluid. We demonstrate the integration of the healing module onto printed circuit boards and the ability of maze solving. We model and perform experiments on the influence of the geometry of conductive particles as well as the terminal impedances of the route on the healing efficiency. The typical heal rate is 10 μm/s with healed route having mean resistance of 8 kΩ across a 200 micron gap and depending on the materials and concentrations used.

  2. Maze solving automatons for self-healing of open interconnects: Modular add-on for circuit boards

    NASA Astrophysics Data System (ADS)

    Nair, Aswathi; Raghunandan, Karthik; Yaswant, Vaddi; Pillai, Sreelal S.; Sambandan, Sanjiv

    2015-03-01

    We present the circuit board integration of a self-healing mechanism to repair open faults. The electric field driven mechanism physically restores fractured interconnects in electronic circuits and has the ability to solve mazes. The repair is performed by conductive particles dispersed in an insulating fluid. We demonstrate the integration of the healing module onto printed circuit boards and the ability of maze solving. We model and perform experiments on the influence of the geometry of conductive particles as well as the terminal impedances of the route on the healing efficiency. The typical heal rate is 10 μm/s with healed route having mean resistance of 8 kΩ across a 200 micron gap and depending on the materials and concentrations used.

  3. Development of portable fuel cell arrays with printed-circuit technology

    NASA Astrophysics Data System (ADS)

    O'Hayre, Ryan; Braithwaite, Daniel; Hermann, Weston; Lee, Sang-Joon; Fabian, Tibor; Cha, Suk-Won; Saito, Yuji; Prinz, Fritz B.

    Portable hydrogen/oxygen fuel cell power sources were constructed using printed-circuit board (PCB) technology. Multiple iterations of miniature planar fuel cell devices were prototyped, demonstrating fast cycle innovation and dramatic power density improvements in <1 year of development. Several novel flow structure and gas routing designs were explored. Electrical interconnections for configurable voltage were wired on board by printed-circuit traces and vias. Fuel cell device voltages ranging from 1 V single cells to 16 V planar arrays were demonstrated, with power output ranging from <1 to >200 W. The lightweight laminate PCB technology allows the best prototypes to achieve >700 mW/cm 2 area power density and >400 mW/cm 3 volumetric power density. PCB technology offers an intriguing platform for portable fuel cell development below 1 kW. Possibilities for on board diagnostics/control and further power density improvements are envisioned.

  4. An Assay System for Point-of-Care Diagnosis of Tuberculosis using Commercially Manufactured PCB Technology.

    PubMed

    Evans, Daniel; Papadimitriou, Konstantinos I; Greathead, Louise; Vasilakis, Nikolaos; Pantelidis, Panagiotis; Kelleher, Peter; Morgan, Hywel; Prodromakis, Themistoklis

    2017-04-06

    Rapid advances in clinical technologies, detection sensitivity and analytical throughput have delivered a significant expansion in our knowledge of prognostic and diagnostic biomarkers in many common infectious diseases, such as Tuberculosis (TB). During the last decade, a significant number of approaches to TB diagnosis have been attempted at Point-of-Care (PoC), exploiting a large variation of techniques and materials. In this work, we describe an electronics-based Enzyme-Linked ImmunoSorbent Assay (eELISA), using a Lab-on-a-Printed Circuit Board (LoPCB) approach, for TB diagnosis based on cytokine detection. The test relies upon an electrochemical (amperometric) assay, comprising a high-precision bioinstrumentation board and amperometric sensors, produced exclusively using standard PCB manufacturing processes. Electrochemical detection uses standard Au and Ag electrodes together with a bespoke, low-power, multichannel, portable data-acquisition system. We demonstrate high-performance assay chemistry performed at microfluidic volumes on Au pads directly at the PCB surface with improved limit of detection (~10 pg/mL) over standard colorimetric ELISA methods. The assay has also been implemented in plasma, showing the utility of the system for medical applications. This work is a significant step towards the development of a low-cost, portable, high-precision diagnostic and monitoring technology, which once combined with appropriate PCB-based microfluidic networks will provide complete LoPCB platforms.

  5. A Novel Transient Fault Current Sensor Based on the PCB Rogowski Coil for Overhead Transmission Lines.

    PubMed

    Liu, Yadong; Xie, Xiaolei; Hu, Yue; Qian, Yong; Sheng, Gehao; Jiang, Xiuchen

    2016-05-21

    The accurate detection of high-frequency transient fault currents in overhead transmission lines is the basis of malfunction detection and diagnosis. This paper proposes a novel differential winding printed circuit board (PCB) Rogowski coil for the detection of transient fault currents in overhead transmission lines. The interference mechanism of the sensor surrounding the overhead transmission line is analyzed and the guideline for the interference elimination is obtained, and then a differential winding printed circuit board (PCB) Rogowski coil is proposed, where the branch and return line of the PCB coil were designed to be strictly symmetrical by using a joining structure of two semi-rings and collinear twisted pair differential windings in each semi-ring. A serial test is conducted, including the frequency response, linearity, and anti-interference performance as well as a comparison with commercial sensors. Results show that a PCB Rogowski coil has good linearity and resistance to various external magnetic field interferences, thus enabling it to be widely applied in fault-current-collecting devices.

  6. A Novel Transient Fault Current Sensor Based on the PCB Rogowski Coil for Overhead Transmission Lines

    PubMed Central

    Liu, Yadong; Xie, Xiaolei; Hu, Yue; Qian, Yong; Sheng, Gehao; Jiang, Xiuchen

    2016-01-01

    The accurate detection of high-frequency transient fault currents in overhead transmission lines is the basis of malfunction detection and diagnosis. This paper proposes a novel differential winding printed circuit board (PCB) Rogowski coil for the detection of transient fault currents in overhead transmission lines. The interference mechanism of the sensor surrounding the overhead transmission line is analyzed and the guideline for the interference elimination is obtained, and then a differential winding printed circuit board (PCB) Rogowski coil is proposed, where the branch and return line of the PCB coil were designed to be strictly symmetrical by using a joining structure of two semi-rings and collinear twisted pair differential windings in each semi-ring. A serial test is conducted, including the frequency response, linearity, and anti-interference performance as well as a comparison with commercial sensors. Results show that a PCB Rogowski coil has good linearity and resistance to various external magnetic field interferences, thus enabling it to be widely applied in fault-current-collecting devices. PMID:27213402

  7. Amperometric IFN-γ immunosensors with commercially fabricated PCB sensing electrodes.

    PubMed

    Moschou, Despina; Greathead, Louise; Pantelidis, Panagiotis; Kelleher, Peter; Morgan, Hywel; Prodromakis, Themistoklis

    2016-12-15

    Lab-on-a-Chip (LoC) technology has the potential to revolutionize medical Point-of-Care diagnostics. Currently, considerable research efforts are focused on innovative production technologies that will make commercial upscaling of lab-on-chip products financially viable. Printed circuit board (PCB) manufacturing techniques have several advantages in this field. In this paper we focus on transferring a complete IFN-γ enzyme-linked immune-sorbent assay (ELISA) onto a commercial PCB electrochemical biosensing platform, We adapted a commercially available ELISA to detect the enzyme product TMB/H2O2 using amperometry, successfully reproducing the colorimetry-obtained ELISA standard curve. The results demonstrate the potential for the integration of these components into an automated, disposable, electronic ELISA Lab-on-PCB diagnostic platform. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Long-lasting FR-4 surface hydrophilisation towards commercial PCB passive microfluidics

    NASA Astrophysics Data System (ADS)

    Vasilakis, Nikolaos; Moschou, Despina; Carta, Daniela; Morgan, Hywel; Prodromakis, Themistoklis

    2016-04-01

    Printed circuit boards (PCB) technologies are an attractive system for simple sensing and microfluidic systems. Controlling the surface properties of PCB material is an important part of this technology and to date there has been no study on long-term hydrophilisation stability of these materials. In this work, the effect of different oxygen plasma input power and treatment duration times on the wetting properties of FR-4 surfaces was investigated by sessile droplet contact angle measurements. Super and weakly hydrophilic behaviour was achieved and the retention time of these properties was studied, with the hydrophilic nature being retained for at least 26 days. To demonstrate the applicability of this treatment method, a commercially manufactured microfluidic structure made from a multilayer PCB (3-layer FR-4 stack) was exposed to oxygen plasma at the optimum conditions. The structures could be filled with deionised (DI) water under capillary flow unlike the virgin devices.

  9. Generation of copper rich metallic phases from waste printed circuit boards

    SciTech Connect

    Cayumil, R.; Khanna, R.; Ikram-Ul-Haq, M.; Rajarao, R.; Hill, A.; Sahajwalla, V.

    2014-10-15

    Highlights: • Recycling and material recovery from waste printed circuit boards is very complex. • Thermoset polymers, ceramics and metals are present simultaneously in waste PCBs. • Heat treatment of PCBs was carried out at 1150 °C under inert conditions. • Various metallic phases could be segregated out as copper based metallic droplets. • Carbon and ceramics residues can be further recycled in a range of applications. - Abstract: The rapid consumption and obsolescence of electronics have resulted in e-waste being one of the fastest growing waste streams worldwide. Printed circuit boards (PCBs) are among the most complex e-waste, containing significant quantities of hazardous and toxic materials leading to high levels of pollution if landfilled or processed inappropriately. However, PCBs are also an important resource of metals including copper, tin, lead and precious metals; their recycling is appealing especially as the concentration of these metals in PCBs is considerably higher than in their ores. This article is focused on a novel approach to recover copper rich phases from waste PCBs. Crushed PCBs were heat treated at 1150 °C under argon gas flowing at 1 L/min into a horizontal tube furnace. Samples were placed into an alumina crucible and positioned in the cold zone of the furnace for 5 min to avoid thermal shock, and then pushed into the hot zone, with specimens exposed to high temperatures for 10 and 20 min. After treatment, residues were pulled back to the cold zone and kept there for 5 min to avoid thermal cracking and re-oxidation. This process resulted in the generation of a metallic phase in the form of droplets and a carbonaceous residue. The metallic phase was formed of copper-rich red droplets and tin-rich white droplets along with the presence of several precious metals. The carbonaceous residue was found to consist of slag and ∼30% carbon. The process conditions led to the segregation of hazardous lead and tin clusters in the

  10. A novel dismantling process of waste printed circuit boards using water-soluble ionic liquid.

    PubMed

    Zeng, Xianlai; Li, Jinhui; Xie, Henghua; Liu, Lili

    2013-10-01

    Recycling processes for waste printed circuit boards (WPCBs) have been well established in terms of scientific research and field pilots. However, current dismantling procedures for WPCBs have restricted the recycling process, due to their low efficiency and negative impacts on environmental and human health. This work aimed to seek an environmental-friendly dismantling process through heating with water-soluble ionic liquid to separate electronic components and tin solder from two main types of WPCBs-cathode ray tubes and computer mainframes. The work systematically investigates the influence factors, heating mechanism, and optimal parameters for opening solder connections on WPCBs during the dismantling process, and addresses its environmental performance and economic assessment. The results obtained demonstrate that the optimal temperature, retention time, and turbulence resulting from impeller rotation during the dismantling process, were 250 °C, 12 min, and 45 rpm, respectively. Nearly 90% of the electronic components were separated from the WPCBs under the optimal experimental conditions. This novel process offers the possibility of large industrial-scale operations for separating electronic components and recovering tin solder, and for a more efficient and environmentally sound process for WPCBs recycling.

  11. Integrated printed circuit board device for cell lysis and nucleic acid extraction.

    PubMed

    Marshall, Lewis A; Wu, Liang Li; Babikian, Sarkis; Bachman, Mark; Santiago, Juan G

    2012-11-06

    Preparation of raw, untreated biological samples remains a major challenge in microfluidics. We present a novel microfluidic device based on the integration of printed circuit boards and an isotachophoresis assay for sample preparation of nucleic acids from biological samples. The device has integrated resistive heaters and temperature sensors as well as a 70 μm × 300 μm × 3.7 cm microfluidic channel connecting two 15 μL reservoirs. We demonstrated this device by extracting pathogenic nucleic acids from 1 μL dispensed volume of whole blood spiked with Plasmodium falciparum. We dispensed whole blood directly onto an on-chip reservoir, and the system's integrated heaters simultaneously lysed and mixed the sample. We used isotachophoresis to extract the nucleic acids into a secondary buffer via isotachophoresis. We analyzed the convective mixing action with micro particle image velocimetry (micro-PIV) and verified the purity and amount of extracted nucleic acids using off-chip quantitative polymerase chain reaction (PCR). We achieved a clinically relevant limit of detection of 500 parasites per microliter. The system has no moving parts, and the process is potentially compatible with a wide range of on-chip hybridization or amplification assays.

  12. Comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids.

    PubMed

    Chen, Mengjun; Huang, Jinxiu; Ogunseitan, Oladele A; Zhu, Nengming; Wang, Yan-min

    2015-07-01

    Waste printed circuit boards (WPCBs) are attracting increasing concerns because the recovery of its content of valuable metallic resources is hampered by the presence of hazardous substances. In this study, we used ionic liquids (IL) to leach copper from WPCBs. [BSO3HPy]OTf, [BSO3HMIm]OTf, [BSO4HPy]HSO4, [BSO4HMim]HSO4 and [MIm]HSO4 were selected. Factors that affect copper leaching rate were investigated in detail and their leaching kinetics were also examined with the comparison of [Bmim]HSO4. The results showed that all six IL acids could successfully leach copper out, with near 100% recovery. WPCB particle size and leaching time had similar influences on copper leaching performance, while IL acid concentration, hydrogen peroxide addition, solid to liquid ratio, temperature, showed different influences. Moreover, IL acid with HSO4(-) was more efficient than IL acid with CF3SO3(-). These six IL acids indicate a similar behavior with common inorganic acids, except temperature since copper leaching rate of some IL acids decreases with its increase. The results of leaching kinetics studies showed that diffusion plays a more important role than surface reaction, whereas copper leaching by inorganic acids is usually controlled by surface reaction. This innovation provides a new option for recovering valuable materials such as copper from WPCBs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. An Evaluation of Prototype Circuit Boards Assembled with a Sn-Ag Bi Solder

    SciTech Connect

    ARTAKI,I.; RAY,U.; REJENT,JEROME A.; VIANCO,PAUL T.

    1999-09-01

    An evaluation was performed which examined the aging of surface mount solder joints assembled with 91.84Sn-3.33Ag-4.83Bi solder. Defect analysis of the as-fabricated test vehicles revealed excellent solderability, good package alignment, and a minimum number of voids. Continuous DC electrical monitoring of the solder joints did not reveal opens during as many as 10,000 thermal cycles (0 C, 100 C). The solder joints exhibited no significant degradation through 2500 cycles, based upon an absence of microstructural damage and sustained shear and pull strengths of chip capacitors and J-leaded solder joints, respectively. Thermal cycles of 5000 and 10,000 resulted in some surface cracking of the solder fillets and coatings. In a few cases, deeper cracks were observed in the thinner reaches of several solder fillets. There was no deformation or cracking in the solder located in the gap between the package I/O and the circuit board pad nor in the interior of the fillets, both locations that would raise concerns of joint mechanical integrity. A drop in the chip capacitor shear strength was attributed to crack growth near the top of the fillet.

  14. Column bioleaching copper and its kinetics of waste printed circuit boards (WPCBs) by Acidithiobacillus ferrooxidans.

    PubMed

    Chen, Shu; Yang, Yuankun; Liu, Congqiang; Dong, Faqin; Liu, Bijun

    2015-12-01

    Application of bioleaching process for metal recovery from electronic waste has received an increasing attention in recent years. In this work, a column bioleaching of copper from waste printed circuit boards (WPCBs) by Acidithiobacillus ferrooxidans has been investigated. After column bioleaching for 28d, the copper recovery reached at 94.8% from the starting materials contained 24.8% copper. Additionally, the concentration of Fe(3+) concentration varied significantly during bioleaching, which inevitably will influence the Cu oxidation, thus bioleaching process. Thus the variation in Fe(3+) concentration should be taken into consideration in the conventional kinetic models of bioleaching process. Experimental results show that the rate of copper dissolution is controlled by external diffusion rather than internal one because of the iron hydrolysis and formation of jarosite precipitates at the surface of the material. The kinetics of column bioleaching WPCBs remains unchanged because the size and morphology of precipitates are unaffected by maintaining the pH of solution at 2.25 level. In bioleaching process, the formation of jarosite precipitate can be prevented by adding dilute sulfuric acid and maintaining an acidic condition of the leaching medium. In such way, the Fe(2)(+)-Fe(3+) cycle process can kept going and create a favorable condition for Cu bioleaching. Our experimental results show that column Cu bioleaching from WPCBs by A. ferrooxidans is promising. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Disposing and recycling waste printed circuit boards: disconnecting, resource recovery, and pollution control.

    PubMed

    Wang, Jianbo; Xu, Zhenming

    2015-01-20

    Over the past decades, China has been suffering from negative environmental impacts from distempered e-waste recycling activities. After a decade of effort, disassembly and raw materials recycling of environmentally friendly e-waste have been realized in specialized companies, in China, and law enforcement for illegal activities of e-waste recycling has also been made more and more strict. So up to now, the e-waste recycling in China should be developed toward more depth and refinement to promote industrial production of e-waste resource recovery. Waste printed circuit boards (WPCBs), which are the most complex, hazardous, and valuable components of e-waste, are selected as one typical example in this article that reviews the status of related regulations and technologies of WPCBs recycling, then optimizes, and integrates the proper approaches in existence, while the bottlenecks in the WPCBs recycling system are analyzed, and some preliminary experiments of pinch technologies are also conducted. Finally, in order to provide directional guidance for future development of WPCBs recycling, some key points in the WPCBs recycling system are proposed to point towards a future trend in the e-waste recycling industry.

  16. Application of glass-nonmetals of waste printed circuit boards to produce phenolic moulding compound.

    PubMed

    Guo, Jie; Rao, Qunli; Xu, Zhenming

    2008-05-01

    The aim of this study was to investigate the feasibility of using glass-nonmetals, a byproduct of recycling waste printed circuit boards (PCBs), to replace wood flour in production of phenolic moulding compound (PMC). Glass-nonmetals were attained by two-step crushing and corona electrostatic separating processes. Glass-nonmetals with particle size shorter than 0.07 mm were in the form of single fibers and resin powder, with the biggest portion (up to 34.6 wt%). Properties of PMC with glass-nonmetals (PMCGN) were compared with reference PMC and the national standard of PMC (PF2C3). When the adding content of glass-nonmetals was 40 wt%, PMCGN exhibited flexural strength of 82 MPa, notched impact strength of 2.4 kJ/m(2), heat deflection temperature of 175 degrees C, and dielectric strength of 4.8 MV/m, all of which met the national standard. Scanning electron microscopy (SEM) showed strong interfacial bonding between glass fibers and the phenolic resin. All the results showed that the use of glass-nonmetals as filler in PMC represented a promising method for resolving the environmental pollutions and reducing the cost of PMC, thus attaining both environmental and economic benefits.

  17. Catalytic pyrolysis characteristics of scrap printed circuit boards by TG-FTIR.

    PubMed

    Zhao, Chunhu; Zhang, Xiaoping; Shi, Lin

    2017-03-01

    In the present work, pyrolysis and catalytic pyrolysis of waste printed circuit boards (WPCBs) was carried out in the coupling of Thermo Gravimetric Analysis and Fourier Transform Infrared Spectroscopy (TG-FTIR) under nitrogen atmosphere. The reaction temperature was increased from 30 to 700°C, while the heating rates were varied from 10 to 40°C/min. Experimental results show that the effect of catalyst on the WPCBs particles pyrolysis was significance. Compared with another two combustion-supporting agents (MgO, CaO), the whole pyrolysis process was optimized when the catalyst ZSM-5 was added into the WPCBs particles. The distributed activation energy model (DAEM) was used to analyze the kinetic parameters of the WPCBs pyrolysis. It was found that values of frequency factor (k0) changed with different activation energy (E) values during pyrolysis process. The activation energy values range from 129.15 to 280.53kJ/mol, and the frequency factor values range from 9.02×10(10) to 4.21×10(22)s(-1). The generated major products for the catalytic pyrolysis of WPCBs were H2, CO2, CO, H2O, phenols and aromatics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Recycling of waste printed circuit boards: a review of current technologies and treatment status in China.

    PubMed

    Huang, Kui; Guo, Jie; Xu, Zhenming

    2009-05-30

    From the use of renewable resources and environmental protection viewpoints, recycling of waste printed circuit boards (PCBs) receives wide concerns as the amounts of scrap PCBs increases dramatically. However, treatment for waste PCBs is a challenge due to the fact that PCBs are diverse and complex in terms of materials and components makeup as well as the original equipment's manufacturing processes. Recycle technology for waste PCBs in China is still immature. Previous studies focused on metals recovery, but resource utilization for nonmetals and further separation of the mixed metals are relatively fewer. Therefore, it is urgent to develop a proper recycle technology for waste PCBs. In this paper, current status of waste PCBs treatment in China was introduced, and several recycle technologies were analyzed. Some advices against the existing problems during recycling process were presented. Based on circular economy concept in China and complete recycling and resource utilization for all materials, a new environmental-friendly integrated recycling process with no pollution and high efficiency for waste PCBs was provided and discussed in detail.

  19. Bioleaching of metal concentrates of waste printed circuit boards by mixed culture of acidophilic bacteria.

    PubMed

    Zhu, Nengwu; Xiang, Yun; Zhang, Ting; Wu, Pingxiao; Dang, Zhi; Li, Ping; Wu, Jinhua

    2011-08-30

    Metal concentrates of printed circuit boards (PCBs) are the residue valuable metals from which non-metallic components are removed. The non-metallic components show bacterial toxicity in bioleaching process and can be recycled as well. In this study, the effects of initial pH, initial Fe(II) concentration, metal concentrate dosage, particle size, and inoculation quantity on the bioleaching were investigated so as to determine the optimum conditions and evaluate the feasibility of bioleaching of metal concentrates of PCBs by mixed culture of acidophilic bacteria (MCAB). The results showed that the initial pH and Fe(II) concentration played an important role in copper extraction and precipitate formation. Under the optimized conditions of initial pH 2.00, 12g/L initial Fe(II), 12g/L metal concentrate dosage, 10% inoculation quantity, and 60-80 mesh particle size, 96.8% the copper leaching efficiency was achieved in 45h, and aluminum and zinc 88.2% and 91.6% in 98h, respectively. All findings demonstrated that metals could be efficiently leached from metal concentrates of waste PCBs by using the MCAB, and the leaching period was shorten from about 8 days to 45h.

  20. A Novel Designed Bioreactor for Recovering Precious Metals from Waste Printed Circuit Boards

    PubMed Central

    Jujun, Ruan; Jie, Zheng; Jian, Hu; Zhang, Jianwen

    2015-01-01

    For recovering precious metals from waste printed circuit boards (PCBs), a novel hybrid technology including physical and biological methods was developed. It consisted of crushing, corona-electrostatic separation, and bioleaching. Bioleaching process is the focus of this paper. A novel bioreactor for bioleaching was designed. Bioleaching was carried out using Pseudomonas chlororaphis. Bioleaching experiments using mixed particles of Au and Cu were performed and leachate contained 0.006 mg/L, 2823 mg/L Au+ and Cu2+ respectively. It showed when Cu existed, the concentrations of Au were extremely small. This provided the feasibility to separate Cu from Au. The method of orthogonal experimental design was employed in the simulation bioleaching experiments. Experimental results showed the optimized parameters for separating Cu from Au particles were pH 7.0, temperature 22.5 °C, and rotation speed 80 r/min. Based on the optimized parameters obtained, the bioreactor was operated for recovering mixed Au and Cu particles. 88.1 wt.% of Cu and 76.6 wt.% of Au were recovered. The paper contributed important information to recover precious metals from waste PCBs. PMID:26316021

  1. Fabrication of thermally stable and cost-effective polymeric waveguide for optical printed-circuit board.

    PubMed

    Kim, Do-Won; Ahn, Seung Ho; Cho, In-Kui; Im, Dong-Min; Shorab Muslim, Shirazy Md; Park, Hyo-Hoon

    2008-10-13

    A thermally stable polymeric optical waveguide has been fabricated using ultraviolet (UV)-curable epoxy resins for the core and clad materials. A simple and cost-effective fabrication method that uses reusable polydimethylsiloxane (PDMS) masters has been developed. The 12-channel under-clad layer of the UV-cured epoxy was prepared using a PDMS master whose embossed channels had been fabricated by a polycarbonate (PC) secondary master. The thermal stability of the fabricated waveguide was tested at 200 degrees C for one hour. The optical waveguide was not damaged physically by thermal stress. Propagation losses detected by a cut-back method were 0.16 dB/cm and 0.26 dB/cm, respectively, before and after the thermal stability test at 850 nm. Loss increase after the thermal treatment can be attributed to the formation of the absorbing and scattering sources. This waveguide can be applied for areas that require thermal stability such as an optical printed-circuit board.

  2. Neutralization/purification of the wastewaters from printed circuit boards production using waste by-products.

    PubMed

    Orescanin, Visnja; Kollar, Robert; Halkijevic, Ivan; Kuspilic, Marin; Flegar, Vanja

    2014-01-01

    The purpose of this work was development of a new method for the neutralization/purification of printed circuit boards wastewater (PCBW) originating from Zagreb, Croatia, using two industrial by-products. PCBW was characterized with low pH value (2.11) and high concentration of TDS (50190 mg L(-1)), copper (4190 mg L(-1)) and iron (2660 mg L(-1)). Waste base (WB), by-product of the alumina production, and waste sludge, by-product of the electrochemical treatment of groundwater, were employed as neutralization/adsorption agents. Due to its high neutralization capacity WB was used for pH adjustment to pH 8 and heavy metals removal from both effluents, yet the final removal of the contaminants down to the regulated values was assessed by adsorption/coagulation with the iron and aluminum rich waste sludge. Following the combined treatment the removal efficiency of iron and copper was higher than 99.99% with their final concentration in the treated water of 0.151 mg L(-1) and 0.129 mg L(-1), respectively. Following the ozone base oxidation the removal efficiency of the organic contaminants was more than 83%. The successful application of the industrial waste by-products for neutralization/purification of the PCBW with the removal efficiencies of the contaminants comparable or better than those obtained with conventional treatment represented the main advantage of our presented method.

  3. Enhancement of simultaneous gold and copper extraction from computer printed circuit boards using Bacillus megaterium.

    PubMed

    Arshadi, M; Mousavi, S M

    2015-01-01

    In this research simultaneous gold and copper recovery from computer printed circuit boards (CPCBs) was evaluated using central composite design of response surface methodology (CCD-RSM). To maximize simultaneous metals' extraction from CPCB waste four factors which affected bioleaching were selected to be optimized. A pure culture of Bacillus megaterium, a cyanogenic bacterium, was used to produce cyanide as a leaching agent. Initial pH 10, pulp density 2g/l, particle mesh#100 and glycine concentration 0.5g/l were obtained as optimal conditions. Gold and copper were extracted simultaneously at about 36.81 and 13.26% under optimum conditions, respectively. To decrease the copper effect as an interference agent in the leaching solution, a pretreatment strategy was examined. For this purpose firstly using Acidithiobacillus ferrooxidans copper in the CPCB powder was totally extracted, then the residual sediment was subjected to further experiments for gold recovery by B. megaterium. Using pretreated sample under optimal conditions 63.8% gold was extracted.

  4. Conversion of bromine during thermal decomposition of printed circuit boards at high temperature.

    PubMed

    Jin, Yu-qi; Tao, Lin; Chi, Yong; Yan, Jian-hua

    2011-02-15

    The conversion of bromine during the thermal decomposition of printed circuit boards (PCBs) was investigated at isothermal temperatures ranging from 800°C to 1100°C by using a quartz tube furnace. The influence of temperature, oxygen concentrations (0%, 10% and 21% in the nitrogen-oxygen atmosphere) and content of steam on conversion of bromine was studied. With the increment of temperature, the conversion from organic bromine in the PCBs to inorganic bromine in the gaseous fraction increased from 69.0% to 96.4%. The bromine was mainly evolved as HBr and Br(2) in oxidizing condition and the Br(2)/HBr mass ratio increased at stronger oxidizing atmosphere. The experimental results also indicated that the existence of steam can reduce the formation of Br(2). Furthermore, co-combustion of PCBs with S and CaO, both as addition agents, was investigated, respectively. In the presence of SO(2), Br(2)/HBr mass ratio obviously decreased. Moreover, the utilization of calcium oxide can efficiently promote the conversion of organic bromine to inorganic bromine. According to the experimental results, incinerating PCBs at high temperature can efficiently destroy the organobrominated compounds that are considered to be possible precursors of polybrominated dibenzeo-p-dioxins and dibenzofurans (PBDD/Fs), but the Br(2) and HBr in flue gas should be efficiently controlled.

  5. Characterization of Printed Circuit Boards for Metal and Energy Recovery after Milling and Mechanical Separation

    PubMed Central

    Bizzo, Waldir A.; Figueiredo, Renata A.; de Andrade, Valdelis F.

    2014-01-01

    The proper disposal of electrical and electronic waste is currently a concern of researchers and environmental managers not only because of the large volume of such waste generated, but also because of the heavy metals and toxic substances it contains. This study analyzed printed circuit boards (PCBs) from discarded computers to determine their metal content and characterized them as solid waste and fuel. The analysis showed that PCBs consist of approximately 26% metal, made up mainly of copper, lead, aluminum, iron and tin, as well as other heavy metals such as cadmium and nickel. Comparison with the results of other studies indicated that the concentration of precious metals (gold and silver) has declined over time. Analysis of the leachate revealed high concentrations of cadmium and lead, giving the residue the characteristics of hazardous waste. After milling the PCBs, we found that larger amounts of metal were concentrated in smaller fractions, while the lightest fraction, obtained by density separation, had a gross calorific value of approximately 11 MJ/kg, although with a high ash content. Milling followed by density separation proved potentially useful for recovery of metals and energy-rich fractions. PMID:28788692

  6. High temperature investigations on optimising the recovery of copper from waste printed circuit boards.

    PubMed

    Cayumil, R; Ikram-Ul-Haq, M; Khanna, R; Saini, R; Mukherjee, P S; Mishra, B K; Sahajwalla, V

    2017-01-12

    High temperature pyrolysis investigations were carried out on waste printed circuit boards (PCBs) in the temperature range 800-1000°C under inert conditions, with an aim to determine optimal operating conditions for the recovery of copper. Pyrolysis residues were characterized using ICP-OES analysis, SEM/EDS and XRD investigations. Copper foils were successfully recovered after pyrolysis at 800°C for 10-20 min; the levels of Pb and Sn present were found to be quite low and these were generally present near the foil edges. The relative proportions of Pb and Sn became progressively higher at longer heating times due to enhanced diffusion of these molten metals in solid copper. While a similar behaviour was observed at 900°C, the pyrolysis at 1000°C resulted in copper forming Cu-Sn-Pb alloys; copper foils could no longer be recovered. Optimal conditions were identified for the direct recovery of copper from waste PCBs with minimal processing. This approach is expected to make significant contributions towards enhancing material recovery, process efficiency and the environmental sustainability of recycling e-waste. Pyrolysis at lower temperatures, short heating times, coupled with reductions in process steps are expected to significantly reduce energy consumption and pollution associated with the handling and processing of waste PCBs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Environmental friendly technology for aluminum electrolytic capacitors recycling from waste printed circuit boards.

    PubMed

    Wang, Jianbo; Xu, Zhenming

    2017-03-15

    up to now, the recycling of e-waste should be developed towards more depth and refinement to promote industrial production of e-waste resource recovery. in the present study, the recycling of aluminum electrolytic capacitors (AECs) from waste printed circuit boards (WPCBs) is focused on. First of all, AECs are disassembled from WPCBs by a self-designed machine; meanwhile, the disassembled AECs are subjected to an integrated process, involving heating treatment, crushing, sieving, and magnetic separating, to recover aluminum and iron; finally, the off-gas and residue generated during the aforementioned processes are analyzed to evaluate environmental risks. The results indicate that 96.52% and 98.68% of aluminum and iron, respectively, can be recovered from AECs under the optimal condition. The off-gas generated during the process is mainly composed of elements of C, H, and O, indicating that the off-gas is non-toxic and could be re-utilized as clean energy source. The residue according with toxicity characteristics leaching standard can be landfilled safely in sanitary landfill site. The present study provides an environmentally friendly and industrial application potential strategy to recycle AECs to promote e-waste recycling industry.

  8. Treatment of waste printed circuit board by green solvent using ionic liquid.

    PubMed

    Zhu, P; Chen, Y; Wang, L Y; Zhou, M

    2012-10-01

    Recycling of waste printed circuit boards (WPCBs) is an important subject not only for the protection of environment but also for the recovery of valuable materials. A feasibility study was conducted to dissolve bromine epoxy resins of WPCBs using ionic liquid (IL) of 1-ethyl-3-methylimizadolium tetrafluoroborate [EMIM(+)][BF(4)(-)] (nonaqueous green solvent) for recovering copper foils and glass fibers. Experimental results indicated that the initial delamination had seen from the cross-section of the WPCBs by mean of metallographic microscope and digital camera when WPCBs were heated in [EMIM(+)][BF(4)(-)] at 240°C for a duration of 30 min. When temperature was increased to 260°C for a duration of 10 min, the bromine epoxy resins of WPCBs were throughout dissolved into [EMIM(+)][BF(4)(-)] and the separations of copper foils and glass fibers from WPCBs were completed. This clean and non-polluting technology offers a new way to recycle valuable materials from WPCBs and prevent the environmental pollution of WPCBs effectively.

  9. Dissolution of brominated epoxy resins by dimethyl sulfoxide to separate waste printed circuit boards.

    PubMed

    Zhu, Ping; Chen, Yan; Wang, Liangyou; Qian, Guangren; Zhang, Wei Jie; Zhou, Ming; Zhou, Jin

    2013-03-19

    Improved methods are required for the recycling of waste printed circuit boards (WPCBs). In this study, WPCBs (1-1.5 cm(2)) were separated into their components using dimethyl sulfoxide (DMSO) at 60 °C for 45 min and a metallographic microscope was used to verify their delamination. An increased incubation time of 210 min yielded a complete separation of WPCBs into their components, and copper foils and glass fibers were obtained. The separation time decreased with increasing temperature. When the WPCB size was increased to 2-3 cm(2), the temperature required for complete separation increased to 90 °C. When the temperature was increased to 135 °C, liquid photo solder resists could be removed from the copper foil surfaces. The DMSO was regenerated by rotary decompression evaporation, and residues were obtained. Fourier transform infrared spectroscopy (FT-IR), thermal analysis, nuclear magnetic resonance, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to verify that these residues were brominated epoxy resins. From FT-IR analysis after the dissolution of brominated epoxy resins in DMSO it was deduced that hydrogen bonding may play an important role in the dissolution mechanism. This novel technology offers a method for separating valuable materials and preventing environmental pollution from WPCBs.

  10. Pressure leaching of metals from waste printed circuit boards using sulfuric acid

    NASA Astrophysics Data System (ADS)

    Jha, Manis K.; Lee, Jae-Chun; Kumari, Archana; Choubey, Pankaj K.; Kumar, Vinay; Jeong, Jinki

    2011-08-01

    Printed circuit boards (PCBs) are essential components of electronic equipments which contain various metallic values. This paper reports a hydrometallurgical recycling process for waste PCBs, which consists of the novel pretreatment consisting of organic swelling of PCBs followed by sulfuric acid leaching of metals from waste PCBs. To recycle the waste PCBs, experiments were carried out for the recovery of copper from the crushed and organic swelled materials of waste PCBs using sulfuric acid leaching in presence of hydrogen peroxide under atmospheric and pressure condition. The leaching of PCBs at 90°C, pulp density 100 g/L under atmospheric condition, using 6M sulfuric acid resulted in the dissolution of a minor amount of copper due to the presence of plastic coating on the surface of metallic layers. On the other hand, when the liberated metal sheets from organic swelled PCBs were treated with dilute sulfuric acid of concentration 2M along with hydrogen peroxide in an autoclave under oxygen atmosphere, the percentage recovery of copper was found to increase from 59.63% to 97.01% with an increase in hydrogen peroxide concentration from 5 to 15% (v/v) keeping constant pulp density 30 g/L.

  11. A Novel Designed Bioreactor for Recovering Precious Metals from Waste Printed Circuit Boards.

    PubMed

    Jujun, Ruan; Jie, Zheng; Jian, Hu; Zhang, Jianwen

    2015-08-28

    For recovering precious metals from waste printed circuit boards (PCBs), a novel hybrid technology including physical and biological methods was developed. It consisted of crushing, corona-electrostatic separation, and bioleaching. Bioleaching process is the focus of this paper. A novel bioreactor for bioleaching was designed. Bioleaching was carried out using Pseudomonas chlororaphis. Bioleaching experiments using mixed particles of Au and Cu were performed and leachate contained 0.006 mg/L, 2823 mg/L Au(+) and Cu(2+) respectively. It showed when Cu existed, the concentrations of Au were extremely small. This provided the feasibility to separate Cu from Au. The method of orthogonal experimental design was employed in the simulation bioleaching experiments. Experimental results showed the optimized parameters for separating Cu from Au particles were pH 7.0, temperature 22.5 °C, and rotation speed 80 r/min. Based on the optimized parameters obtained, the bioreactor was operated for recovering mixed Au and Cu particles. 88.1 wt.% of Cu and 76.6 wt.% of Au were recovered. The paper contributed important information to recover precious metals from waste PCBs.

  12. Wood plastic composite produced by nonmetals from pulverized waste printed circuit boards.

    PubMed

    Guo, Jie; Tang, Yinen; Xu, Zhenming

    2010-01-01

    Nonmetals reclaimed from waste printed circuit boards (PCBs) are used to replace wood flour in the production of wood plastic composite (WPC). To evaluate property durability against weather exposure, the effects of accelerated aging process on the properties of WPC are investigated. The results show that filling of nonmetals in WPC improves the flexural strength and tensile strength, and reduces screw withdrawal strength. Before hollow WPC with 15% nonmetals (H-15-WPC) underwent aging process, H-15-WPC had a flexural strength of 25.8 MPa, a tensile strength of 9.8 MPa, a charpy impact strength of 3.4 kJ/m(2), and face/edge screw withdrawal strength of 121/115 N/mm. It is found that flexural strength of H-15-WPC decreases linearly with the increase of accelerated aging cycles, and the effects of aging test on tensile and impact strength of H-15-WPC are minor. For solid WPC, the accelerated aging test decreases screw withdrawal strength slightly. All the results indicate that nonmetals of waste PCBs can be reused as an alternative for wood flour in WPC products rather than resorting to their landfill or combustion.

  13. Pyrolysis characteristics of the mixture of printed circuit board scraps and coal powder.

    PubMed

    Hao, Juan; Wang, Haifeng; Chen, Shuhe; Cai, Bin; Ge, Linhan; Xia, Wencheng

    2014-10-01

    Thermogravimetric (TG) analysis and infrared spectroscopy were used to analyze the pyrolysis characteristics of printed circuit board scraps (PCBs), coal powder and their mixtures under nitrogen atmosphere. The experimental results show that there is a large difference between waste PCBs and coal powder in pyrolysis processing. The pyrolysis properties of the mixing samples are the result of interaction of the PCBs and coal powder, which is influenced by the content of mixture. The degree of pyrolysis and pyrolysis properties of the mixture are much better than that of the single component. The TG and the differential thermogravimetric (DTG) curves of the PCBs mixed with coal powder move towards the high-temperature zone with increasing amount of coal powder and subsequently the DTG peak also becomes wider. The Coats-Redfern integral method was used to determine the kinetic parameters of pyrolysis reaction mechanism with the different proportion of mixture. The gas of pyrolysis mainly composes of CO2, CO, H2O and some hydrocarbon. The bromide characteristic absorption peak has been detected obviously in the pyrolysis gas of PCBs. On the contrary, the absorption peak of the bromide is not obvious in pyrolysis gas of the PCBs samples adding 40% coal powder.

  14. Leaching of metals from large pieces of printed circuit boards using citric acid and hydrogen peroxide.

    PubMed

    Jadhav, Umesh; Su, C; Hocheng, Hong

    2016-12-01

    In the present study, the leaching of metals from large pieces of computer printed circuit boards (CPCBs) was studied. A combination of citric acid (0.5 M) and 1.76 M hydrogen peroxide (H2O2) was used to leach the metals from CPCB piece. The influence of system variables such as H2O2 concentration, concentration of citric acid, shaking speed, and temperature on the metal leaching process was investigated. The complete metal leaching was achieved in 4 h from a 4 × 4 cm CPCB piece. The presence of citric acid and H2O2 together in the leaching solution is essential for complete metal leaching. The optimum addition amount of H2O2 was 5.83 %. The citric acid concentration and shaking speed had an insignificant effect on the leaching of metals. The increase in the temperature above 30 °C showed a drastic effect on metal leaching process.

  15. Metals recovering from waste printed circuit boards (WPCBs) using molten salts.

    PubMed

    Flandinet, L; Tedjar, F; Ghetta, V; Fouletier, J

    2012-04-30

    Recycling of waste electrical and electronic equipments (WEEE) has been taken into consideration in the literature due to the large quantity of concerned wastes and their hazardous contents. The situation is so critical that EU published European Directives imposing collection and recycling with a minimum of material recovery [1]. Moreover, WEEEs contain precious metals, making the recycling of these wastes economically interesting, but also some critical metals and their recycling leads to resource conservation. This paper reports on a new approach for recycling waste printed circuit boards (WPCBs). Molten salts and specifically molten KOH-NaOH eutectic is used to dissolve glasses, oxides and to destruct plastics present in wastes without oxidizing the most valuable metals. This method is efficient for recovering a copper-rich metallic fraction, which is, moreover, cleared of plastics and glasses. In addition, analyses of gaseous emission show that this method is environmentally friendly since most of the process gases, such as carbon monoxide and dioxide and halogens, are trapped in the highly basic molten salt. In other respects, under operation without oxygen, a large quantity of hydrogen is produced and might be used as fuel gas or as synthesis gas, leading to a favourable energy balance for this new process. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Copper recovery and gold enrichment from waste printed circuit boards by mediated electrochemical oxidation.

    PubMed

    Fogarasi, Szabolcs; Imre-Lucaci, Florica; Imre-Lucaci, Arpád; Ilea, Petru

    2014-05-30

    The present study aims to develop an eco-friendly chemical-electrochemical process for the simultaneous recovery of copper and separation of a gold rich residue from waste printed circuit boards (WPCBs). The process was carried out by employing two different types of reactors coupled in series: a leaching reactor with a perforated rotating drum, for the dissolution of base metals and a divided electrochemical reactor for the regeneration of the leaching solution with the parallel electrowinning of copper. The process performances were evaluated on the basis of the dissolution efficiency, current efficiency and specific energy consumptions. Finally a process scale up was realized taking into consideration the optimal values of the operating parameters. The laboratory scale leaching plant allowed the recovery of a high purity copper deposit (99.04wt.%) at a current efficiency of 63.84% and specific energy consumption of 1.75kWh/kg cooper. The gold concentration in the remained solid residue was 25 times higher than the gold concentration in the initial WPCB samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. [Newly leaching method of copper from waste print circuit board using hydrochloric acid/n-butylamine/copper sulfate].

    PubMed

    Wang, Hong-Yan; Cui, Zhao-Jie; Yao, Ya-Wei

    2010-12-01

    A newly leaching method of copper from waste print circuit board was established by using hydrochloric acid-n-butylamine-copper sulfate mixed solution. The conditions of leaching were optimized by changing the hydrochloric acid, n-butylamine, copper sulfate,temperature and other conditions using copper as target mimics. The results indicated that copper could be leached completely after 8 h at 50 degrees C, hydrochloric acid concentration of 1.75 mol/L, n-butylamine concentration of 0.25 mol/L, and copper sulfate mass of 0.96 g. Under the conditions, copper leaching rates in waste print circuit board samples was up to 95.31% after 9 h. It has many advantages such as better effects, low cost, mild reaction conditions, leaching solution recycling.

  18. Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace

    SciTech Connect

    Ni Mingjiang; Xiao Hanxi; Chi Yong; Yan Jianhua; Buekens, Alfons; Jin Yuqi; Lu Shengyong

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer The combustion efficiency of waste printed circuit boards (PCBs) depends on temperature, excess air factor, and high temperature zone residence time. Temperature has the most significant impact. Under the proposed condition, combustion of waste PCBs alone is quite complete within the furnace. Black-Right-Pointing-Pointer High temperature prompts a more complete bromine release and conversion. When temperature is high enough, 99.9% organobrominated compounds, the potential precursors for brominated dixoins formation, are destroyed efficiently and convert to inorganic bromine in flue gas, as HBr and Br{sub 2}. Black-Right-Pointing-Pointer Temperature has crucial influence over the inhibition of HBr conversion to Br{sub 2}, while the oxygen partial pressure plays a reverse role in the conversion to a very small extent. Increasing temperature will decrease the volume percentage ratio of Br{sub 2}/HBr in flue gas greatly. Black-Right-Pointing-Pointer The thermodynamic equilibrium approach of bromine conversion was investigated. The two forms of inorganic bromine in flue gas substantially reach thermodynamic equilibrium within 0.25 s. Under the proposed operating condition, the reaction of Br transfer and conversion finish. - Abstract: High temperature combustion experiments of waste printed circuit boards (PCBs) were conducted using a lab-scale system featuring a continuously-fed drop tube furnace. Combustion efficiency and the occurrence of inorganic bromine (HBr and Br{sub 2}) were systematically studied by monitoring the main combustion products continuously. The influence of furnace temperature (T) was studied from 800 to 1400 Degree-Sign C, the excess air factor (EAF) was varied from 1.2 to 1.9 and the residence time in the high temperature zone (RT{sub HT}) was set at 0.25, 0.5, or 0.75 s. Combustion efficiency depends on temperature, EAF and RT{sub HT}; temperature has the most significant effect. Conversion of organic

  19. Using vacuum pyrolysis and mechanical processing for recycling waste printed circuit boards.

    PubMed

    Long, Laishou; Sun, Shuiyu; Zhong, Sheng; Dai, Wencan; Liu, Jingyong; Song, Weifeng

    2010-05-15

    The constant growth in generation of waste printed circuit boards (WPCB) poses a huge disposal problem because they consist of a heterogeneous mixture of organic and metallic chemicals as well as glass fiber. Also the presence of heavy metals, such as Pb and Cd turns this scrap into hazardous waste. Therefore, recycling of WPCB is an important subject not only from the recovery of valuable materials but also from the treatment of waste. The aim of this study was to present a recycling process without negative impact to the environment as an alternative for recycling WPCB. In this work, a process technology containing vacuum pyrolysis and mechanical processing was employed to recycle WPCB. At the first stage of this work, the WPCB was pyrolyzed under vacuum in a self-made batch pilot-scale fixed bed reactor to recycle organic resins contained in the WPCB. By vacuum pyrolysis the organic matter was decomposed to gases and liquids which could be used as fuels or chemical material resources, however, the inorganic WPCB matter was left unaltered as solid residues. At the second stage, the residues obtained at the first stage were investigated to separate and recover the copper through mechanical processing such as crushing, screening, and gravity separation. The copper grade of 99.50% with recovery of 99.86% based on the whole WPCB was obtained. And the glass fiber could be obtained by calcinations in a muffle furnace at 600 degrees C for 10 min. This study had demonstrated the feasibility of vacuum pyrolysis and mechanical processing for recycling WPCB. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  20. Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace.

    PubMed

    Ni, Mingjiang; Xiao, Hanxi; Chi, Yong; Yan, Jianhua; Buekens, Alfons; Jin, Yuqi; Lu, Shengyong

    2012-03-01

    High temperature combustion experiments of waste printed circuit boards (PCBs) were conducted using a lab-scale system featuring a continuously-fed drop tube furnace. Combustion efficiency and the occurrence of inorganic bromine (HBr and Br(2)) were systematically studied by monitoring the main combustion products continuously. The influence of furnace temperature (T) was studied from 800 to 1400°C, the excess air factor (EAF) was varied from 1.2 to 1.9 and the residence time in the high temperature zone (RT(HT)) was set at 0.25, 0.5, or 0.75 s. Combustion efficiency depends on temperature, EAF and RT(HT); temperature has the most significant effect. Conversion of organic bromine from flame retardants into HBr and Br(2) depends on temperature and EAF. Temperature has crucial influence over the ratio of HBr to Br(2), whereas oxygen partial pressure plays a minor role. The two forms of inorganic bromine seem substantially to reach thermodynamic equilibrium within 0.25s. High temperature is required to improve the combustion performance: at 1200°C or higher, an EAF of 1.3 or more, and a RT(HT) exceeding 0.75 s, combustion is quite complete, the CO concentration in flue gas and remained carbon in ash are sufficiently low, and organobrominated compounds are successfully decomposed (more than 99.9%). According to these results, incineration of waste PCBs without preliminary separation and without additives would perform very well under certain conditions; the potential precursors for brominated dioxins formation could be destroyed efficiently. Increasing temperature could decrease the volume percentage ratio of Br(2)/HBr in flue gas greatly.

  1. Fluorescence detection test by black printed circuit board based microfluidic channel for polymerase chain reaction.

    PubMed

    Hwang, Ji-Soo; Kim, Yu-Seop; Song, Hye-Jeong; Kim, Jong-Dae; Park, Chan-Young

    2015-01-01

    This paper proposes the optimal structure of a PCB-based micro PCR chip constructed on a PCB substrate using commercial adhesive tapes and plastic covers. The solder mask of the PCB substrate was coated black, and the area where the reaction chamber is attached was legend printed with white silk to minimize the noise during fluorescence detection. The performance of the PCR and fluorescence detection was compared using 6 types of reaction chambers, each made with different double-sided tapes. Three of the chambers were unsuccessful in completing the PCR. The performance of the other three chambers that successfully amplified DNA was compared using Taqman probe for Chlamydia Trachomatis DNA. The amplified product was illuminated diagonally with a blue LED to excite the product just before imaging, and the LED was turned off when the image was captured to prevent quenching of the probe. The images were taken 10 seconds prior to the last extension step for each cycle using a DSLR camera. The experiments were run as a quartet for each three chambers made with different double-sided tape. The results showed that there were significant difference between the three tapes.

  2. Simple fabricating PCB-based inter digital capacitor for glucose biosensor

    NASA Astrophysics Data System (ADS)

    Jamaluddin, Anif; Taufik, Usman; Iriani, Yofentina; Budiawanti, Sri; Suyitno

    2017-01-01

    This paper presents the simple fabrication of interdigital capacitor (IDC) using print circuit board (PCB) for glucose biosensor. PCB type FR04 laminated with Cu as electrode was used as sensor base. The IDC pattern of sensor was designed by computer aided design program and printed with a laser printer on plastic polymers. Then, the IDC pattern was transferred into PCB by a laminating machine. The etching process of PCB was done by immersing in ferric chloride liquid to form Cu pattern. There were five patterns of sensors including 5, 10, 15, 20 and 25 patterns. The capacitance value of PCB was measured with RCL meter when IDC biosensor was put in air, aquades, and glucose liquid with various moles of glucose (0.02, 0.04, 0.06, 0.08, 0.1M). In air medium, the increase of pattern number of IDC sensor (from 5 to 25) caused the sensor capacitance rose from 22 pf to 46 pf. In addition, the capacitance of sensor was dramatically increased until 0.36 µf while IDC sensor with 25 patterns was put in aquades medium. In liquid glucose medium, the capacitance of IDC biosensor with 25 patterns increased until 0.58 µf on 0.1 M glucose liquid.

  3. The lab-on-PCB approach: tackling the μTAS commercial upscaling bottleneck.

    PubMed

    Moschou, Despina; Tserepi, Angeliki

    2017-03-15

    Commercialization of lab-on-a-chip devices is currently the "holy grail" within the μTAS research community. While a wide variety of highly sophisticated chips which could potentially revolutionize healthcare, biology, chemistry and all related disciplines are increasingly being demonstrated, very few chips are or can be adopted by the market and reach the end-users. The major inhibition factor lies in the lack of an established commercial manufacturing technology. The lab-on-printed circuit board (lab-on-PCB) approach, while suggested many years ago, only recently has re-emerged as a very strong candidate, owing to its inherent upscaling potential: the PCB industry is well established all around the world, with standardized fabrication facilities and processes, but commercially exploited currently only for electronics. Owing to these characteristics, complex μTASs integrating microfluidics, sensors, and electronics on the same PCB platform can easily be upscaled, provided more processes and prototypes adapted to the PCB industry are proposed. In this article, we will be reviewing for the first time the PCB-based prototypes presented in the literature to date, highlighting the upscaling potential of this technology. The authors believe that further evolution of this technology has the potential to become a much sought-after standardized industrial fabrication technology for low-cost μTASs, which could in turn trigger the projected exponential market growth of μTASs, in a fashion analogous to the revolution of Si microchips via the CMOS industry establishment.

  4. Effects of PCB Pad Metal Finishes on the Cu-Pillar/Sn-Ag Micro Bump Joint Reliability of Chip-on-Board (COB) Assembly

    NASA Astrophysics Data System (ADS)

    Kim, Youngsoon; Lee, Seyong; Shin, Ji-won; Paik, Kyung-Wook

    2016-06-01

    While solder bumps have been used as the bump structure to form the interconnection during the last few decades, the continuing scaling down of devices has led to a change in the bump structure to Cu-pillar/Sn-Ag micro-bumps. Cu-pillar/Sn-Ag micro-bump interconnections differ from conventional solder bump interconnections in terms of their assembly processing and reliability. A thermo-compression bonding method with pre-applied b-stage non-conductive films has been adopted to form solder joints between Cu pillar/Sn-Ag micro bumps and printed circuit board vehicles, using various pad metal finishes. As a result, various interfacial inter-metallic compounds (IMCs) reactions and stress concentrations occur at the Cu pillar/Sn-Ag micro bumps joints. Therefore, it is necessary to investigate the influence of pad metal finishes on the structural reliability of fine pitch Cu pillar/Sn-Ag micro bumps flip chip packaging. In this study, four different pad surface finishes (Thin Ni ENEPIG, OSP, ENEPIG, ENIG) were evaluated in terms of their interconnection reliability by thermal cycle (T/C) test up to 2000 cycles at temperatures ranging from -55°C to 125°C and high-temperature storage test up to 1000 h at 150°C. The contact resistances of the Cu pillar/Sn-Ag micro bump showed significant differences after the T/C reliability test in the following order: thin Ni ENEPIG > OSP > ENEPIG where the thin Ni ENEPIG pad metal finish provided the best Cu pillar/Sn-Ag micro bump interconnection in terms of bump joint reliability. Various IMCs formed between the bump joint areas can account for the main failure mechanism.

  5. [Copper recovery from artificial bioleaching lixivium of waste printed circuit boards].

    PubMed

    Cheng, Dan; Zhu, Neng-Wu; Wu, Ping-Xiao; Zou, Ding-Hui; Xing, Yi-Jia

    2014-04-01

    The key step to realize metal recovery from bioleaching solutions is the recovery of copper from bioleaching lixivium of waste printed circuit boards in high-grade form. The influences of cathode material, current density, initial pH and initial copper ion concentration on the efficiency and energy consumption of copper recovery from artificial bioleaching lixivium under condition of constant current were investigated using an electro-deposition approach. The results showed that the larger specific surface area of the cathode material (carbon felt) led to the higher copper recovery efficiency (the recovery efficiencies of the anode and the cathode chambers were 96.56% and 99.25%, respectively) and the smaller the total and unit mass product energy consumption (the total and unit mass product energy consumptions were 0.022 kW x h and 15.71 kW x h x kg(-1), respectively). The copper recovery efficiency and energy consumption increased with the increase of current density. When the current density was 155.56 mA x cm(-2), the highest copper recovery efficiencies in the anode and cathode chambers reached 98.51% and 99.37%, respectively. Accordingly, the highest total and unit mass product energy consumptions were 0.037 kW x h and 24.34 kW x h x kg(-1), respectively. The copper recovery efficiency was also significantly affected by the initial copper ion concentration. The increase of the initial copper ion concentration would lead to faster decrease of copper ion concentration, higher total energy consumption, and lower unit mass product consumption. However, the initial pH had no significant effect on the copper recovery efficiency. Under the optimal conditions (carbon felt for cathode materials, current density of 111.11 mA x cm(-2), initial pH of 2.0, and initial copper ion concentration of 10 g x L(-1)), the copper recovery efficiencies of the anode and cathode chambers were 96.75% and 99.35%, and the total and unit mass product energy consumptions were 0.021 kW x h

  6. Generation of copper rich metallic phases from waste printed circuit boards.

    PubMed

    Cayumil, R; Khanna, R; Ikram-Ul-Haq, M; Rajarao, R; Hill, A; Sahajwalla, V

    2014-10-01

    The rapid consumption and obsolescence of electronics have resulted in e-waste being one of the fastest growing waste streams worldwide. Printed circuit boards (PCBs) are among the most complex e-waste, containing significant quantities of hazardous and toxic materials leading to high levels of pollution if landfilled or processed inappropriately. However, PCBs are also an important resource of metals including copper, tin, lead and precious metals; their recycling is appealing especially as the concentration of these metals in PCBs is considerably higher than in their ores. This article is focused on a novel approach to recover copper rich phases from waste PCBs. Crushed PCBs were heat treated at 1150°C under argon gas flowing at 1L/min into a horizontal tube furnace. Samples were placed into an alumina crucible and positioned in the cold zone of the furnace for 5 min to avoid thermal shock, and then pushed into the hot zone, with specimens exposed to high temperatures for 10 and 20 min. After treatment, residues were pulled back to the cold zone and kept there for 5 min to avoid thermal cracking and re-oxidation. This process resulted in the generation of a metallic phase in the form of droplets and a carbonaceous residue. The metallic phase was formed of copper-rich red droplets and tin-rich white droplets along with the presence of several precious metals. The carbonaceous residue was found to consist of slag and ∼30% carbon. The process conditions led to the segregation of hazardous lead and tin clusters in the metallic phase. The heat treatment temperature was chosen to be above the melting point of copper; molten copper helped to concentrate metallic constituents and their separation from the carbonaceous residue and the slag. Inert atmosphere prevented the re-oxidation of metals and the loss of carbon in the gaseous fraction. Recycling e-waste is expected to lead to enhanced metal recovery, conserving natural resources and providing an environmentally

  7. Recycling of non-metallic fractions from waste printed circuit boards: a review.

    PubMed

    Guo, Jiuyong; Guo, Jie; Xu, Zhenming

    2009-09-15

    The major economic driving force for recycling of waste printed circuit boards (PCBs) is the value of the metallic fractions (MFs) of PCBs. The non-metallic fractions (NMFs), which take up almost 70wt% of waste PCBs, were treated by combustion or land filling in the past. However, combustion of the NMFs will cause the formation of highly toxic polybrominated dibenzodioxins and dibenzofurans (PBDD/Fs) while land filling of the NMFs will lead to secondary pollution caused by heavy metals and brominated flame retardants (BFRs) leaching to the groundwater. Therefore, recycling of the NMFs from waste PCBs is drawing more and more attention from the public and the governments. Currently, how to recycle the NMFs environmental soundly has become a significant topic in recycling of waste PCBs. In order to fulfill the better resource utilization of the NMFs, the compositions and characteristics of the NMFs, methods and outcomes of recycling the NMFs from waste PCBs and analysis and treatment for the hazardous substances contained in the NMFs were reviewed in this paper. Thermosetting resin matrix composites, thermoplastic matrix composites, concrete and viscoelastic materials are main applications for physical recycling of the NMFs. Chemical recycling methods consisting of pyrolysis, gasification, supercritical fluids depolymerization and hydrogenolytic degradation can be used to convert the NMFs to chemical feedstocks and fuels. The toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) can be used to determine the toxicity characteristic (TC) of the NMFs and to evaluate the environmental safety of products made from the recycled NMFs. It is believed that physical recycling of the NMFs has been a promising recycling method. Much more work should be done to develop comprehensive and industrialized usage of the NMFs recycled by physical methods. Chemical recycling methods have the advantages in eliminating hazardous substances

  8. Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging

    SciTech Connect

    Palmieri, Roberta; Bonifazi, Giuseppe; Serranti, Silvia

    2014-11-15

    Highlights: • A recycling oriented characterization of end-of-life mobile phones was carried out. • Characterization was developed in a zero-waste-perspective, aiming to recover all the mobile phone materials. • Plastic frames and printed circuit boards were analyzed by electronic and chemical imaging. • Suitable milling/classification strategies were set up to define specialized-pre-concentrated-streams. • The proposed approach can improve the recovery of polymers, base/precious metals, rare earths and critical raw materials. - Abstract: This study characterizes the composition of plastic frames and printed circuit boards from end-of-life mobile phones. This knowledge may help define an optimal processing strategy for using these items as potential raw materials. Correct handling of such a waste is essential for its further “sustainable” recovery, especially to maximize the extraction of base, rare and precious metals, minimizing the environmental impact of the entire process chain. A combination of electronic and chemical imaging techniques was thus examined, applied and critically evaluated in order to optimize the processing, through the identification and the topological assessment of the materials of interest and their quantitative distribution. To reach this goal, end-of-life mobile phone derived wastes have been systematically characterized adopting both “traditional” (e.g. scanning electronic microscopy combined with microanalysis and Raman spectroscopy) and innovative (e.g. hyperspectral imaging in short wave infrared field) techniques, with reference to frames and printed circuit boards. Results showed as the combination of both the approaches (i.e. traditional and classical) could dramatically improve recycling strategies set up, as well as final products recovery.

  9. Graded-index core polymer optical waveguide for high-bandwidth-density optical printed circuit boards: fabrication and characterization

    NASA Astrophysics Data System (ADS)

    Ishigure, Takaaki

    2014-03-01

    We demonstrate that graded-index (GI) core polymer optical waveguides are a promising component realizing highbandwidth- density on-board interconnects. As a method for fabricating GI-circular-core polymer optical waveguides, we introduce the Mosquito method utilizing a microdispenser. The Mosquito method is capable of accurately controlling the core diameter and the inter-core pitch. We also demonstrate that the GI-core polymer waveguides enable remarkably low loss waveguide circuits involving waveguide crossings in a mono layer. We show an alternative technique to realize the low-loss GI-core crossed waveguide: the photo-addressing method which was developed by Sumitomo Bakelite Co., Ltd.

  10. Computational algorithms for analysis of data from thin-film thermoresistors on a radio-electronic printed circuit board

    SciTech Connect

    Korneeva, Anna; Shaydurov, Vladimir

    2016-08-10

    In the paper, the data analysis is considered for thin-film thermoresistors coated on to a radio-electronic printed circuit board to determine possible zones of its overheating. A mathematical model consists in an underdetermined system of linear algebraic equations with an infinite set of solutions. For computing a more real solution, two additional conditions are used: the smoothness of a solution and the positiveness of an increase of temperature during overheating. Computational experiments demonstrate that an overheating zone is determined exactly with a tolerable accuracy of temperature in it.

  11. Computational algorithms for analysis of data from thin-film thermoresistors on a radio-electronic printed circuit board

    NASA Astrophysics Data System (ADS)

    Korneeva, Anna; Shaydurov, Vladimir

    2016-08-01

    In the paper, the data analysis is considered for thin-film thermoresistors coated on to a radio-electronic printed circuit board to determine possible zones of its overheating. A mathematical model consists in an underdetermined system of linear algebraic equations with an infinite set of solutions. For computing a more real solution, two additional conditions are used: the smoothness of a solution and the positiveness of an increase of temperature during overheating. Computational experiments demonstrate that an overheating zone is determined exactly with a tolerable accuracy of temperature in it.

  12. Ultra-thin and low-power optical interconnect module based on a flexible optical printed circuit board

    NASA Astrophysics Data System (ADS)

    Hwang, Sung Hwan; Lee, Woo-Jin; Kim, Myoung Jin; Jung, Eun Joo; Kim, Gye Won; An, Jong Bae; Jung, Ki Young; Cha, Kyung Soon; Rho, Byung Sup

    2012-07-01

    We describe an ultra-thin and low-power optical interconnect module for mobile electronic devices such as mobile phones and notebooks. The module was fabricated by directly packaging optic and electronic components onto a thin and flexible optical printed circuit board having a size of 70×8×0.25 mm. The completed active module has features of thinness (0.5 mm), small size (7×5 mm), very low total power consumption (15.88 mW), and high data rate transmissions (2.5 Gbps).

  13. Toward environmentally-benign utilization of nonmetallic fraction of waste printed circuit boards as modifier and precursor.

    PubMed

    Hadi, Pejman; Ning, Chao; Ouyang, Weiyi; Xu, Meng; Lin, Carol S K; McKay, Gordon

    2015-01-01

    Electronic waste, including printed circuit boards, is growing at an alarming rate due to the accelerated technological progress and the shorter lifespan of the electronic equipment. In the past decades, due to the lack of proper economic and environmentally-benign recycling technologies, a major fraction of e-waste generated was either destined to landfills or incinerated with the sole intention of its disposal disregarding the toxic nature of this waste. Recently, with the increasing public awareness over their environment and health issues and with the enaction of more stringent regulations, environmentally-benign recycling has been driven to be an alternative option partially replacing the traditional eco-unfriendly disposal methods. One of the most favorable green technologies has been the mechanical separation of the metallic and nonmetallic fraction of the waste printed circuit boards. Although metallic fraction, as the most profitable component, is used to generate the revenue of the separation process, the nonmetallic fraction (NMF) has been left isolated. Herein, the recent developments in the application of NMF have been comprehensively reviewed and an eco-friendly emerging usage of NMF as a value-added material for sustainable remediation has been introduced. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Removing lead from metallic mixture of waste printed circuit boards by vacuum distillation: factorial design and removal mechanism.

    PubMed

    Li, Xingang; Gao, Yujie; Ding, Hui

    2013-10-01

    The lead removal from the metallic mixture of waste printed circuit boards by vacuum distillation was optimized using experimental design, and a mathematical model was established to elucidate the removal mechanism. The variables studied in lead evaporation consisted of the chamber pressure, heating temperature, heating time, particle size and initial mass. The low-level chamber pressure was fixed at 0.1 Pa as the operation pressure. The application of two-level factorial design generated a first-order polynomial that agreed well with the data for evaporation efficiency of lead. The heating temperature and heating time exhibited significant effects on the efficiency, which was validated by means of the copper-lead mixture experiments. The optimized operating conditions within the region studied were the chamber pressure of 0.1 Pa, heating temperature of 1023 K and heating time of 120 min. After the conditions were employed to remove lead from the metallic mixture of waste printed circuit boards, the efficiency was 99.97%. The mechanism of the effects was elucidated by mathematical modeling that deals with evaporation, mass transfer and condensation, and can be applied to a wider range of metal removal by vacuum distillation.

  15. Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging.

    PubMed

    Palmieri, Roberta; Bonifazi, Giuseppe; Serranti, Silvia

    2014-11-01

    This study characterizes the composition of plastic frames and printed circuit boards from end-of-life mobile phones. This knowledge may help define an optimal processing strategy for using these items as potential raw materials. Correct handling of such a waste is essential for its further "sustainable" recovery, especially to maximize the extraction of base, rare and precious metals, minimizing the environmental impact of the entire process chain. A combination of electronic and chemical imaging techniques was thus examined, applied and critically evaluated in order to optimize the processing, through the identification and the topological assessment of the materials of interest and their quantitative distribution. To reach this goal, end-of-life mobile phone derived wastes have been systematically characterized adopting both "traditional" (e.g. scanning electronic microscopy combined with microanalysis and Raman spectroscopy) and innovative (e.g. hyperspectral imaging in short wave infrared field) techniques, with reference to frames and printed circuit boards. Results showed as the combination of both the approaches (i.e. traditional and classical) could dramatically improve recycling strategies set up, as well as final products recovery.

  16. Process development for recovery of copper and precious metals from waste printed circuit boards with emphasize on palladium and gold leaching and precipitation.

    PubMed

    Behnamfard, Ali; Salarirad, Mohammad Mehdi; Veglio, Francesco

    2013-11-01

    A novel hydrometallurgical process was proposed for selective recovery of Cu, Ag, Au and Pd from waste printed circuit boards (PCBs). More than 99% of copper content was dissolved by using two consecutive sulfuric acid leaching steps in the presence of H2O2 as oxidizing agents. The solid residue of 2nd leaching step was treated by acidic thiourea in the presence of ferric iron as oxidizing agent and 85.76% Au and 71.36% Ag dissolution was achieved. The precipitation of Au and Ag from acidic thiourea leachate was investigated by using different amounts of sodium borohydride (SBH) as a reducing agent. The leaching of Pd and remained gold from the solid reside of 3rd leaching step was performed in NaClO-HCl-H2O2 leaching system and the effect of different parameters was investigated. The leaching of Pd and specially Au increased by increasing the NaClO concentration up to 10V% and any further increasing the NaClO concentration has a negligible effect. The leaching of Pd and Au increased by increasing the HCl concentration from 2.5 to 5M. The leaching of Pd and Au were endothermic and raising the temperature had a positive effect on leaching efficiency. The kinetics of Pd leaching was quite fast and after 30min complete leaching of Pd was achieved, while the leaching of Au need a longer contact time. The best conditions for leaching of Pd and Au in NaClO-HCl-H2O2 leaching system were determined to be 5M HCl, 1V% H2O2, 10V% NaClO at 336K for 3h with a solid/liquid ratio of 1/10. 100% of Pd and Au of what was in the chloride leachate were precipitated by using 2g/L SBH. Finally, a process flow sheet for the recovery of Cu, Ag, Au and Pd from PCB was proposed.

  17. Assessment of gold and silver in assorted mobile phone printed circuit boards (PCBs): Original article.

    PubMed

    Vats, M C; Singh, S K

    2015-11-01

    Demand for gold and silver has been escalating with increasing usage of electronic equipment globally. Around 267.3 MT of gold and 7275 MT of silver are being consumed annually for manufacturing mobile phones, laptops and other electronic equipment. However, only 15% is recuperated from these equipment; the remainder lies in the storage yards or landfills. The waste comprise glass, plastics, wires, batteries, PCBs, metal casing, etc. The PCB is composed of precious metals, which creates immense purpose for recycling and recovery. This paper characterises and assesses the recoverable metallic fraction of gold and silver from PCBs of mobile phones. The methodology is based on dismantling of the mobile handset and subjecting the PCBs to roasting and acid digestion. The digested samples were analysed by atomic absorption spectroscopy and the content of gold and silver in the PCBs was to be found in the range of 0.009-0.017% and 0.25-0.79% by weight respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Fabrication and functionalization of PCB gold electrodes suitable for DNA-based electrochemical sensing.

    PubMed

    Salvo, P; Henry, O Y F; Dhaenens, K; Acero Sanchez, J L; Gielen, A; Werne Solnestam, B; Lundeberg, J; O'Sullivan, C K; Vanfleteren, J

    2014-01-01

    The request of high specificity and selectivity sensors suitable for mass production is a constant demand in medical research. For applications in point-of-care diagnostics and therapy, there is a high demand for low cost and rapid sensing platforms. This paper describes the fabrication and functionalization of gold electrodes arrays for the detection of deoxyribonucleic acid (DNA) in printed circuit board (PCB) technology. The process can be implemented to produce efficiently a large number of biosensors. We report an electrolytic plating procedure to fabricate low-density gold microarrays on PCB suitable for electrochemical DNA detection in research fields such as cancer diagnostics or pharmacogenetics, where biosensors are usually targeted to detect a small number of genes. PCB technology allows producing high precision, fast and low cost microelectrodes. The surface of the microarray is functionalized with self-assembled monolayers of mercaptoundodecanoic acid or thiolated DNA. The PCB microarray is tested by cyclic voltammetry in presence of 5 mM of the redox probe K3Fe(CN6) in 0.1 M KCl. The voltammograms prove the correct immobilization of both the alkanethiol systems. The sensor is tested for detecting relevant markers for breast cancer. Results for 5 nM of the target TACSTD1 against the complementary TACSTD1 and non-complementary GRP, MYC, SCGB2A1, SCGB2A2, TOP2A probes show a remarkable detection limit of 0.05 nM and a high specificity.

  19. The PCB mark

    SciTech Connect

    1994-12-01

    Polychlorinated biphenyls (PCBs) are a class of organic chemicals that had become widely used in industrial applications due to their practical physical and chemical properties. Historical uses of PCBs include dielectric fluids (used in utility transformers, capacitors, etc.), hydraulic fluids, and other applications requiring stable, fire-retardant materials. Due to findings that PCBs may cause adverse health effects and due to their persistence and accumulation in the environment. The Toxic Substances Control Act (TSCA), enacted on October 11, 1976, banned the manufacture of PCBs after 1978 [Section 6(e)]. The first PCB regulations, promulgated at 40 CFR Part 761, were finalized on February 17, 1978. These PCB regulations include requirements specifying disposal methods and marking (labeling) procedures, and controlling PCB use. To assist the Department of Energy (DOE) in its efforts to comply with the TSCA statute and implementing regulations, the Office of Environmental Guidance has prepared the document ``Guidance on the Management of Polychlorinated Biphenyls (PCBs).`` That document explains the requirements specified in the statute and regulations for managing PCBs including PCB use, storage, transport, and disposal. The requirements outlined at 40 CFR 761.40 through 761.45 specify marking requirements for most PCB items (i.e., any PCB Article, PCB Container, PCB Article Container, or PCB Equipment that contains PCBs). Most PCB items require PCB marks, which are defined as a descriptive name, instructions, cautions, or other information applied to PCB Items or other objects subject to these regulations. The marking regulations include requirements for PCB marks on PCB Items, storage areas, and temporary storage areas. This Information Brief supplements the PCB guidance document by responding to common questions concerning marking requirements for PCBs. It is one of a series of Information Briefs pertinent to PCB management issues.

  20. Manufacturing Methods and Technology for Digital Fault Isolation for Printed Circuit Boards.

    DTIC Science & Technology

    1979-08-25

    the MIRADCOM Digital Autopilot PCBs yielded an average 17 percent improvement in testability. DFI Methodology - Software required to handle test...standards. A literature search of testability articles was evaluated and resulted in a Testability Design Guide. Logic circuits of MIRADCOM Digital Autopilot ...MIRADCOM Missile System Autopilot 390037 Digital Autopilot No. 1 LATCH, AOI, PROM, F/F, RAM 390038 Digital Autopilot No. 2 Microprocessor, RAM, PROM

  1. New technology for separating resin powder and fiberglass powder from fiberglass-resin powder of waste printed circuit boards.

    PubMed

    Li, Jia; Gao, Bei; Xu, Zhenming

    2014-05-06

    New recycling technologies have been developed lately to enhance the value of the fiberglass powder-resin powder fraction (FRP) from waste printed circuit boards. The definite aim of the present paper is to present some novel methods that use the image forces for the separation of the resin powder and fiberglass powder generated from FRP during the corona electrostatic separating process. The particle shape charactization and particle trajectory simulation were performed on samples of mixed non-metallic particles. The simulation results pointed out that particles of resin powder and particles of fiberglass powder had different detach trajectories at the conditions of the same size and certain device parameters. An experiment carried out using a corona electrostatic separator validated the possibility of sorting these particles based on the differences in their shape characteristics. The differences in the physical properties of the different types of particles provided the technical basis for the development of electrostatic separation technologies for the recycling industry.

  2. Integrated bioleaching of copper metal from waste printed circuit board-a comprehensive review of approaches and challenges.

    PubMed

    Awasthi, Abhishek Kumar; Zeng, Xianlai; Li, Jinhui

    2016-11-01

    Waste electrical and electronic equipment (e-waste) is the most rapidly growing waste stream in the world, and the majority of the residues are openly disposed of in developing countries. Waste printed circuit boards (WPCBs) make up the major portion of e-waste, and their informal recycling can cause environmental pollution and health risks. Furthermore, the conventional disposal and recycling techniques-mechanical treatments used to recover valuable metals, including copper-are not sustainable in the long term. Chemical leaching is rapid and efficient but causes secondary pollution. Bioleaching is a promising approach, eco-friendly and economically feasible, but it is slower process. This review considers the recycling potential of microbes and suggests an integrated bioleaching approach for Cu extraction and recovery from WPCBs. The proposed recycling system should be more effective, efficient and both technically and economically feasible.

  3. Pulse Propagation Characteristics of a Multi-layered Printed Circuit Board with a Via and a Bump

    NASA Astrophysics Data System (ADS)

    Kobayashi, Daisuke; Furukawa, Shinichi; Hinata, Takashi

    In this paper, we numerically analyze the transient response of pulse propagation in a multi-layered printed circuit board with a via and a bump. FDTD method is used for our models. It is found from numerical results that; (1) Even if the lengths of the striplines are equal, pulse waveforms passed through a via and a bump are different according to the direction of the striplines. (2) The propagating pulses are influenced by the pad size connecting the bump rather than the bump size. (3) For the model consisted of a via and a bump pulse distortion of responses are substantially improved, if the smaller bump part (including pads) can be designed.

  4. FDTD Calculation of FM-Band Crosstalks between Perpendicular Traces on Printed Circuit Board with Ground-Pattern Slits

    NASA Astrophysics Data System (ADS)

    Ueyama, Hiroya; Maeno, Tsuyoshi; Hirata, Akimasa; Wang, Jianqing; Fujiwara, Osamu

    Electromagnetic disturbances for vehicle-mounted radios are well known to be caused mainly by conduction noise currents flowing out wire harnesses from printed circuit boards (PCBs) having a common ground layer with slits. In this study, in order to investigate how ground-layer slits affect the above conduction noise currents, we paid FM band induced voltages or crosstalks on the trace connected to the wire harnesss, and simulated with the FDTD method the crosstalk levels between two traces perpendicularly fabricated on three kinds of simple PCBs with different ground-layer slits, which were compared with measurement in the frequency range from 10 MHz to 1 GHz. As a result, we could confirm that the FDTD calculation approximately agrees with the measured results, and also that the crosstalk levels do not always increase with the slit number, which can be reduced by the slit layout.

  5. Impedance Discontinuity Reduction Between High-Speed Differential Connectors and PCB Interfaces

    NASA Technical Reports Server (NTRS)

    Navidi, Sal; Agdinaoay, Rodell; Walter, Keith

    2013-01-01

    High-speed serial communication (i.e., Gigabit Ethernet) requires differential transmission and controlled impedances. Impedance control is essential throughout cabling, connector, and circuit board construction. An impedance discontinuity arises at the interface of a high-speed quadrax and twinax connectors and the attached printed circuit board (PCB). This discontinuity usually is lower impedance since the relative dielectric constant of the board is higher (i.e., polyimide approx. = 4) than the connector (Teflon approx. = 2.25). The discontinuity can be observed in transmit or receive eye diagrams, and can reduce the effective link margin of serial data networks. High-speed serial data network transmission improvements can be made at the connector-to-board interfaces as well as improving differential via hole impedances. The impedance discontinuity was improved by 10 percent by drilling a 20-mil (approx. = 0.5-mm) hole in between the pin of a differential connector spaced 55 mils (approx. = 1.4 mm) apart as it is attached to the PCB. The effective dielectric constant of the board can be lowered by drilling holes into the board material between the differential lines in a quadrax or twinax connector attachment points. The differential impedance is inversely proportional to the square root of the relative dielectric constant. This increases the differential impedance and thus reduces the above described impedance discontinuity. The differential via hole impedance can also be increased in the same manner. This technique can be extended to multiple smaller drilled holes as well as tapered holes (i.e., big in the middle followed by smaller ones diagonally).

  6. Optimization of Cvd Diamond Coating Type on Micro Drills in Pcb Machining

    NASA Astrophysics Data System (ADS)

    Lei, X. L.; He, Y.; Sun, F. H.

    2016-12-01

    The demand for better tools for machining printed circuit boards (PCBs) is increasing due to the extensive usage of these boards in digital electronic products. This paper is aimed at optimizing coating type on micro drills in order to extend their lifetime in PCB machining. First, the tribotests involving micro crystalline diamond (MCD), nano crystalline diamond (NCD) and bare tungsten carbide (WC-Co) against PCBs show that NCD-PCB tribopair exhibits the lowest friction coefficient (0.35) due to the unique nano structure and low surface roughness of NCD films. Thereafter, the dry machining performance of the MCD- and NCD-coated micro drills on PCBs is systematically studied, using diamond-like coating (DLC) and TiAlN-coated micro drills as comparison. The experiments show that the working lives of these micro drills can be ranked as: NCD>TiAlN>DLC>MCD>bare WC-Co. The superior cutting performance of NCD-coated micro drills in terms of the lowest flank wear growth rate, no tool degradation (e.g. chipping, tool tipping) appearance, the best hole quality as well as the lowest feed force may come from the excellent wear resistance, lower friction coefficient against PCB as well as the high adhesive strength on the underneath substrate of NCD films.

  7. Optomechanical design and characterization of a printed-circuit-board-based free-space optical interconnect package.

    PubMed

    Zheng, X; Marchand, P J; Huang, D; Kibar, O; Ozkan, N S; Esener, S C

    1999-09-10

    We present a proof of concept and a feasibility demonstration of a practical packaging approach in which free-space optical interconnects (FSOI's) can be integrated simply on electronic multichip modules (MCM's) for intra-MCM-board interconnects. Our system-level packaging architecture is based on a modified folded 4f imaging system that has been implemented with only off-the-shelf optics, conventional electronic packaging, and passive-assembly techniques to yield a potentially low-cost and manufacturable packaging solution. The prototypical system as built supports 48 independent FSOI channels with 8 separate laser and detector chips, for which each chip consists of a one-dimensional array of 12 devices. All the chips are assembled on a single substrate that consists of a printed circuit board or a ceramic MCM. Optical link channel efficiencies of greater than 90% and interchannel cross talk of less than -20 dB at low frequency have been measured. The system is compact at only 10 in.3 (25.4 cm3) and is scalable, as it can easily accommodate additional chips as well as two-dimensional optoelectronic device arrays for increased interconnection density.

  8. Wideband vibrational electromagnetic energy harvesters with nonlinear polyimide springs based on rigid-flex printed circuit boards technology

    NASA Astrophysics Data System (ADS)

    Chiu, Yi; Hong, Hao-Chiao; Hsu, Wei-Hung

    2016-12-01

    A wideband vibrational electromagnetic energy harvester employing nonlinear spring effects is proposed and demonstrated. The harvesters were designed and fabricated by commercial rigid-flex printed circuit boards technology. Rigid FR-4 boards were used for mechanical support and coil winding, whereas flexible polyimide films were patterned for mechanical springs and mass platforms. Two sets of coils were patterned and fabricated in the harvester with an internal coil resistance of about 16 Ω each. Two rare-earth magnets were attached to the central platform as shuttle mass. The total dimension of the harvester was 20 × 20 × 4 mm3. In vibration tests, nonlinearity could be observed even at 0.1 grms vibration level due to the spring hardening effect. The frequency for peak induced voltage increased from 187 Hz at low vibration to 382 Hz at 5 grms vibration. The effective half-power bandwidth increased from 8 Hz at 0.1 grms to 32 Hz at 1 grms and 52 Hz at 5 grms due to the hysteresis in frequency response. For a matched load and 1 grms vibration at 250 Hz, the maximum output power was 160 nW, corresponding to a power density of 100 nW cm-3.

  9. High temperature transformations of waste printed circuit boards from computer monitor and CPU: Characterisation of residues and kinetic studies.

    PubMed

    Rajagopal, Raghu Raman; Rajarao, Ravindra; Sahajwalla, Veena

    2016-11-01

    This paper investigates the high temperature transformation, specifically the kinetic behaviour of the waste printed circuit board (WPCB) derived from computer monitor (single-sided/SSWPCB) and computer processing boards - CPU (multi-layered/MLWPCB) using Thermo-Gravimetric Analyser (TGA) and Vertical Thermo-Gravimetric Analyser (VTGA) techniques under nitrogen atmosphere. Furthermore, the resulting WPCB residues were subjected to characterisation using X-ray Fluorescence spectrometry (XRF), Carbon Analyser, X-ray Photoelectron Spectrometer (XPS) and Scanning Electron Microscopy (SEM). In order to analyse the material degradation of WPCB, TGA from 40°C to 700°C at the rates of 10°C, 20°C and 30°C and VTGA at 700°C, 900°C and 1100°C were performed respectively. The data obtained was analysed on the basis of first order reaction kinetics. Through experiments it is observed that there exists a substantial difference between SSWPCB and MLWPCB in their decomposition levels, kinetic behaviour and structural properties. The calculated activation energy (EA) of SSWPCB is found to be lower than that of MLWPCB. Elemental analysis of SSWPCB determines to have high carbon content in contrast to MLWPCB and differences in materials properties have significant influence on kinetics, which is ceramic rich, proving to have differences in the physicochemical properties. These high temperature transformation studies and associated analytical investigations provide fundamental understanding of different WPCB and its major variations.

  10. Development of nondestructive testing techniques for plated-through holes in multilayer printed circuit boards

    NASA Technical Reports Server (NTRS)

    Anthony, P. L.; Mcmurtrey, J. E.

    1971-01-01

    The development of a nondestructive test with the capability to interrogate plated-through holes as small as 0.51 millimeters inside diameter is discussed. The system can detect defects such as holes, voids, cracks, and thin spots that reduce the current carrying capability of plates-through interconnects by 20 percent or more. Efforts were directed toward the design and fabrication of magnetic circuitry mutual coupling probes and to evaluate the effectiveness of these devices for detecting in multilayer board plated-through holes.

  11. Magnetic markers detection using PCB fluxgate array

    NASA Astrophysics Data System (ADS)

    Janosek, M.; Ripka, P.; Platil, A.

    2009-04-01

    We used an array of race-track fluxgate sensors, manufactured with printed circuit board (PCB) technology, forming a sensor head for detection of ferromagnetic and paramagnetic markers. The sensors were arranged perpendicularly to the measuring plane and we measured the difference of their output, giving us the horizontal gradient of normal component of the measured field. Due to the close match of the sensor's parameters, subtraction of the fluxgate output signals could be done directly at the input of a lock-in amplifier, increasing the signal-to-noise ratio for small gradients. When moving the sensor head, we were able to map field gradients smaller than 6 nT/mm, which was verified while measuring the magnetic markers on a dollar bill, while suppressing the background field by a factor of 5. In a line-scanning mode, we scanned a marker formed by a 0.2 mm diameter Permalloy wire in a distance of up to 10 mm. With the help of perpendicular ac excitation at 30 Hz, we were able to detect a 0.1 ml Endorem iron-oxide superparamagnetic marker at 2 mm; volume of 0.6 ml was detectable at 10 mm.

  12. Laser-written polymer waveguides for embedded printed circuit board computing applications

    NASA Astrophysics Data System (ADS)

    Kruse, Kevin L.; Middlebrook, Christopher T.

    2014-03-01

    Integrating polymer optical waveguides (WGs) for board-to-board high speed data communications require prototyping samples for proof-of-concept studies before moving to large scale production. A laser direct writing (LDW) method is shown as a cost savings alternative to photolithographic prototyping large substrate samples. The LDW setup consists of a 3-axis high-precision motion platform with a commercially available UV laser diode coupled to a lens-capped single mode fiber. The correlation between writing parameters and the resulting waveguide dimensions is discussed theoretically and confirmed experimentally with Dow Corning® OE-4140 UV-Cured Optical Elastomer Core and Dow Corning® OE-4141 UV-Cured Optical Elastomer Cladding for both multimode and single-mode feasibility. Laser written waveguide radial bends and crossings are also evaluated to show manufacturing capabilities for advanced prototyping designs. Polymer waveguides fabricated with the LDW method are experimentally validated with losses comparable to polymer waveguides manufactured with the photolithographic process (< 0.05 dB/cm).

  13. Infant phantom head circuit board for EEG head phantom and pediatric brain simulation

    NASA Astrophysics Data System (ADS)

    Almohsen, Safa

    The infant's skull differs from an adult skull because of the characteristic features of the human skull during early development. The fontanels and the conductivity of the infant skull influence surface currents, generated by neurons, which underlie electroencephalography (EEG) signals. An electric circuit was built to power a set of simulated neural sources for an infant brain activity simulator. Also, in the simulator, three phantom tissues were created using saline solution plus Agarose gel to mimic the conductivity of each layer in the head [scalp, skull brain]. The conductivity measurement was accomplished by two different techniques: using the four points' measurement technique, and a conductivity meter. Test results showed that the optimized phantom tissues had appropriate conductivities to simulate each tissue layer to fabricate a physical head phantom. In this case, the best results should be achieved by testing the electrical neural circuit with the sample physical model to generate simulated EEG data and use that to solve both the forward and the inverse problems for the purpose of localizing the neural sources in the head phantom.

  14. Microconcentrators to recover fill-factor in image photodetectors with pixel on-board processing circuits.

    PubMed

    Donati, Silvano; Martini, Giuseppe; Norgia, Michele

    2007-12-24

    We propose an array of non-imaging micro-concentrators as a mean to recover the loss of sensitivity due to area fill-factor. This is particularly important for those image photo detectors in which complex circuit functions are required and a substantial fraction of the pixel area is consumed, like e.g., 3D camera, SPAD arrays, fluorescence analyzers, etc., but also in CMOS sensors. So far, the low fill-factor was an unacceptable loss of sensitivity precluding from the development of such devices, whereas by using a concentrator array a recovery is possible, up to the inverse square of numerical aperture of the objective lens. By ray tracing, we calculate the concentration factors of several geometries of non-imaging concentrator, i.e., truncated cone, parabolic and compound parabolic, both reflective and refractive. The feasibility of a sizeable recovery of fill-factor (up to 50) is demonstrated.

  15. Rapid prototyping of interfacing microcomponents for printed circuit board-level optical interconnects

    NASA Astrophysics Data System (ADS)

    Van Erps, Jürgen; Vervaeke, Michael; Thienpont, Hugo

    2012-01-01

    One of the important challenges for the deployment of the emerging breed of nanotechnology components is interfacing them with the external world, preferably accomplished with low-cost micro-optical devices. For the fabrication of this kind of micro-optical components, we make use of deep proton writing (DPW) as a generic rapid prototyping technology. DPW consists of bombarding polymer samples with swift protons, which results after chemical processing steps in high quality micro-optical components. The strength of the DPW micro-machining technology is the ability to fabricate monolithic building blocks that include micro-optical and mechanical functionalities which can be precisely integrated into more complex photonic systems. In this paper we give an overview of the process steps of the technology and we present several examples of micro-optical and micro-mechanical components, fabricated through DPW, targeting applications in printed circuit baordlevel optical interconnections. These include: high-precision 2-D fiber connectors, discrete out-of-plane coupling structures featuring high-quality 45° and curved micro-mirrors, arrays of high aspect ratio micro-pillars and backplane connectors. While DPW is clearly not a mass fabrication technique as such, one of its assets is that once the master component has been prototyped, a metal mould can be generated from the DPW master by applying electroplating. After removal of the plastic master, this metal mould can be used as a shim in a final microinjection moulding or hot embossing step. This way, the master component can be mass-produced at low cost in a wide variety of high-tech plastics.

  16. Simultaneous recovery of Ni and Cu from computer-printed circuit boards using bioleaching: statistical evaluation and optimization.

    PubMed

    Arshadi, M; Mousavi, S M

    2014-12-01

    Computer printed circuit boards (CPCBs) have a rich metal content and are produced in high volume, making them an important component of electronic waste. The present study used a pure culture of Acidithiobacillus ferrooxidans to leach Cu and Ni from CPCBs waste. The adaptation phase began at 1g/l CPCBs powder with 10% inoculation and final pulp density was reached at 20g/l after about 80d. Four effective factors including initial pH, particle size, pulp density, and initial Fe(3+) concentration were optimized to achieve maximum simultaneous recovery of Cu and Ni. Their interactions were also identified using central composite design in response surface methodology. The suggested optimal conditions were initial pH 3, initial Fe(3+) 8.4g/l, pulp density 20g/l and particle size 95μm. Nearly 100% of Cu and Ni were simultaneously recovered under optimum conditions. Finally, bacterial growth characteristics versus time at optimum conditions were plotted. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Recycling of organic materials and solder from waste printed circuit boards by vacuum pyrolysis-centrifugation coupling technology.

    PubMed

    Zhou, Yihui; Wu, WenBiao; Qiu, Keqiang

    2011-12-01

    Here, we focused on the recycling of waste printed circuit boards (WPCBs) using vacuum pyrolysis-centrifugation coupling technology (VPCT) aiming to obtain valuable feedstock and resolve environmental pollution. The two types of WPCBs were pyrolysed at 600°C for 30 min under vacuum condition. During the pyrolysis process, the solder of WPCBs was separated and recovered when the temperature range was 400-600°C, and the rotating drum was rotated at 1000 rpm for 10 min. The type-A of WPCBs pyrolysed to form an average of 67.91 wt.% residue, 27.84 wt.% oil, and 4.25 wt.% gas; and pyrolysis of the type-B of WPCBs led to an average mass balance of 72.22 wt.% residue, 21.57 wt.% oil, and 6.21 wt.% gas. The GC-MS and FT-IR analyses showed that the two pyrolysis oils consisted mainly of phenols and substituted phenols. The pyrolysis oil can be used for fuel or chemical feedstock for further processing. The recovered solder can be recycled directly and it can also be a good resource of lead and tin for refining. The pyrolysis residues contained various metals, glass fibers and other inorganic materials, which could be recovered after further treatment. The pyrolysis gases consisted mainly of CO, CO(2), CH(4), and H(2), which could be collected and recycled.

  18. Performance and thermal behavior of wood plastic composite produced by nonmetals of pulverized waste printed circuit boards.

    PubMed

    Guo, Jie; Tang, Yinen; Xu, Zhenming

    2010-07-15

    A new kind of wood plastic composite (WPC) was produced by compounding nonmetals from waste printed circuit boards (PCBs), recycled high-density polyethylene (HDPE), wood flour and other additives. The blended granules were then extruded to profile WPC products by a conical counter-rotating twin-screw extruder. The results showed that the addition of nonmetals in WPC improved the flexural strength and tensile strength and reduced screw withdrawal strength. When the added content of nonmetals was 40%, the flexural strength of WPC was 23.4 MPa, tensile strength was 9.6 MPa, impact strength was 3.03 J/m(2) and screw withdrawal strength was 1755 N. Dimensional stability and fourier transform infrared spectroscopy (FTIR) of WPC panels were also investigated. Furthermore, thermogravimetric analysis showed that thermal degradation of WPC mainly included two steps. The first step was the decomposition of wood flour and nonmetals from 260 to 380 degrees C, and the second step was the decomposition of HDPE from 440 to 500 degrees C. The performance and thermal behavior of WPC produced by nonmetals from PCBs achieves the standard of WPC. It offers a novel method to treat nonmetals from PCBs. 2010 Elsevier B.V. All rights reserved.

  19. Real-time monitoring system for improving corona electrostatic separation in the process of recovering waste printed circuit boards.

    PubMed

    Li, Jia; Zhou, Quan; Xu, Zhenming

    2014-12-01

    Although corona electrostatic separation is successfully used in recycling waste printed circuit boards in industrial applications, there are problems that cannot be resolved completely, such as nonmetal particle aggregation and spark discharge. Both of these problems damage the process of separation and are not easy to identify during the process of separation in industrial applications. This paper provides a systematic study on a real-time monitoring system. Weight monitoring systems were established to continuously monitor the separation process. A Virtual Instrumentation program written by LabVIEW was utilized to sample and analyse the mass increment of the middling product. It includes four modules: historical data storage, steady-state analysis, data computing and alarm. Three kinds of operating conditions were used to verify the applicability of the monitoring system. It was found that the system achieved the goal of monitoring during the separation process and realized the function of real-time analysis of the received data. The system also gave comprehensible feedback on the accidents of material blockages in the feed inlet and high-voltage spark discharge. With the warning function of the alarm system, the whole monitoring system could save the human cost and help the new technology to be more easily applied in industry.

  20. A novel reutilization method for waste printed circuit boards as flame retardant and smoke suppressant for poly (vinyl chloride).

    PubMed

    Xiu, Fu-Rong; Weng, Huiwei; Qi, Yingying; Yu, Gending; Zhang, Zhigang; Zhang, Fu-Shen

    2016-09-05

    In this study, a novel reutilization method for waste printed circuit boards (PCBs) as flame retardant and smoke suppressant for poly (vinyl chloride) (PVC) was successfully testified. A supercritical water oxidation (SCWO) process was applied to treat waste PCBs before they could be used as flame retardants of PVC. The results indicated that SCWO conditions had a significant effect on the flame retarding and smoke suppressing properties of waste PCBs for PVC. Cu2O, CuO, and SnO2 were the main active ingredients in waste PCBs-derived flame retardants. A conversion of Cu elements (Cu(0)→Cu(+)→Cu(2+)) during SCWO process with the increase of reaction temperature was found to be the key influence factor for the flame retarding properties of SCWO-treated PCBs. The experiment results also showed that there was a synergistic effect of flame retardancy between Cu(+) and Cu(2+). After the optimized SCWO treatment, SCWO-treated PCBs significantly improved the flame retardancy and smoke suppression of PVC. Limiting oxygen index (LOI) and char yield (CY) increased with increasing SCWO-treated PCBs content in PVC, while smoke density rating (SDR) and maximum smoke density (MSD) decreased markedly. The mechanical properties of PVC samples were influenced in different degree by adding different content SCWO-treated PCBs.

  1. Construction and Gluing of G10 Frames and Printed Circuit Boards to be used in COMPASS Drift Chamber 5

    NASA Astrophysics Data System (ADS)

    Britto, Vivek

    2014-09-01

    COMPASS is a fixed-target nuclear physics experiment at CERN which explores the internal structure of the proton. One specific area of research is the measurement of single transverse spin asymmetries in pion beam induced Drell-Yan production of muon pairs from polarized proton targets. The spin dependence of the Drell-Yan cross section may be indicative of contributions from quark orbital angular momentum to the spin of the proton. The University of Illinois at Urbana-Champaign (UIUC), in collaboration with institutes in Taiwan, France, Italy and Germany, is designing and building a new drift chamber, DC5, to replace an aging detector in the COMPASS spectrometer. The frames supporting the anode wires and cathode planes in DC5 are constructed from G10, a fiberglass-epoxy composite. Once the individual sides of each frame have been milled, they are glued together at the corner lap joints. Additionally, printed circuit boards are glued to the anode frames, where sense and field wires will later be soldered. To maintain optimal operation of the drift chamber, the frame thickness after gluing must be within 50 μm of the design value. This presentation will explain the methods employed to achieve the required tolerances for this precision gluing process.

  2. Recycling of metals from pretreated waste printed circuit boards effectively in stirred tank reactor by a moderately thermophilic culture.

    PubMed

    Xia, Ming-Chen; Wang, Ya-Ping; Peng, Tang-Jian; Shen, Li; Yu, Run-Lan; Liu, Yuan-Dong; Chen, Miao; Li, Jiao-Kun; Wu, Xue-Ling; Zeng, Wei-Min

    2017-06-01

    To seek a feasible technique for processing waste printed circuit boards (PCBs), pretreatment of PCBs by table separation and further bioleached by moderate thermophiles in a stirred tank reactor were investigated. The shaking table separation, conducted after grinding and sieving of PCBs, produced two fractions: metal-rich parts (RPCBs), which is more suitable for pyrometallurgy process than untreated PCBs, and metal-poor parts (PPCBs) with only 8.83% metals was then bioleached by a mixed culture of moderate thermophiles effectively. After adaptation, the mixed culture could tolerate 80 g/L PPCBs. The bioleaching results showed that metals recovery was 85.23% Zn, 76.59% Cu and 70.16% Al in only 7 days. Trace Pb and Sn were detected in the leachate because of precipitating. The microorganism community structure was analyzed by amplified ribosomal DNA restriction analysis. Two moderately thermophilic bacteria species were identified as Leptospirillum ferriphilum and Acidithiobacillus caldus. Furthermore, uncultured Thermoplasmatales archaeon was also detected in the leaching system. It was also shown that moderate thermophiles revealed best bioleaching ability when compared with mesophiles and the mixture of mesophiles and moderate thermophiles. Finally, we designed a two-stage process model according to the present study to achieve semi-industrial waste PCBs recycling and economic feasibility analysis indicated that the process was profitable. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  3. A long-term static immersion experiment on the leaching behavior of heavy metals from waste printed circuit boards.

    PubMed

    Zhao, Guo-Hua; Luo, Xing-Zhang; Chen, Gui; Zhao, Yong-Jun

    2014-08-01

    Printed circuit boards (PCBs) are the main components of electrical and electronic equipment (EEE). Waste PCBs contain several kinds of heavy metals, including Cu, Pb and Zn. We characterize the leaching of heavy metals (Cu, Pb, Zn and Ni) from waste PCBs in a pH range of 3.0 to 5.6 using a novel approach based on batch pH-static leaching experiments in this work. The results indicate that the leaching behavior of Cu, Pb, Zn and Ni is strongly dependent on pH. Leaching behavior also varies with different pH values and leaching times. The maximum concentrations of Cu, Pb, Zn and Ni in leachate from waste PCBs were 335.00, 17.57, 2.40 and 2.33 mg L(-1), respectively. The highest Pb, Ni, and Cu concentrations leached significantly exceeded the European Union waste-acceptance limit values with respect to inert waste landfills. The leaching of metals follows the shrinking core model with surface reaction control.

  4. The reuse of nonmetals recycled from waste printed circuit boards as reinforcing fillers in the polypropylene composites.

    PubMed

    Zheng, Yanhong; Shen, Zhigang; Cai, Chujiang; Ma, Shulin; Xing, Yushan

    2009-04-30

    The feasibility of reusing nonmetals recycled from waste printed circuit boards (PCBs) as reinforcing fillers in the polypropylene (PP) composites is studied by using both mechanical and vicat softening temperature (VST) tests. The concentration of Cu leaded from the composites is also tested. The mechanical test shows that both tensile and flexural properties of the nonmetals/PP composites can be significantly improved by adding the nonmetals into PP. The maximum increment of tensile strength, tensile modulus, flexural strength and flexural modulus of the PP composites is 28.4%, 62.9%, 87.8% and 133.0%, respectively. As much as 30 wt% nonmetals recycled from waste PCBs can be added in the PP composites without violating the environmental regulation. The VST test shows that the presence of nonmetals can improve the heat resistance of the nonmetals/PP composites for their potential applications. The optimum particle is the fine or medium nonmetals recycled from waste PCBs, and the optimum content of the nonmetals is 30 wt% basing on the comprehensive consideration. All the above results indicate that the reuse of nonmetals as reinforcing fillers in the PP composites represents a promising way for recycling resources and resolving the environmental pollutions.

  5. Morphology, mechanical and thermal oxidative aging properties of HDPE composites reinforced by nonmetals recycled from waste printed circuit boards.

    PubMed

    Yang, Shuangqiao; Bai, Shibing; Wang, Qi

    2016-11-01

    In this study nonmetals recycled from waste printed circuit boards (NPCB) is used as reinforce fillers in high-density polyethylene (HDPE) composites. The morphology, mechanical and thermal oxidative aging properties of NPCB reinforced HDPE composites are assessed and it compared with two other commercial functional filler for the first time. Mechanical test results showed that NPCB could be used as reinforcing fillers in the HDPE composites and mechanical properties especially for stiffness is better than other two commercial fillers. The improved mechanical property was confirmed by the higher aspect ratio and strong interfacial adhesion in scanning electron microscopy (SEM) studies. The heat deflection temperature (HDT) test showed the presence of fiberglass in NPCB can improve the heat resistance of composite for their potential applications. Meanwhile, the oxidation induction time (OIT) and the Fourier transform infrared (FTIR) spectroscopy results showed that NPCB has a near resistance to oxidation as two other commercial fillers used in this paper. The above results show the reuse of NPCB in the HDPE composites represents a promising way for resolving both the environmental pollution and the high-value reuse of resources.

  6. Zinc Oxide Nanorods Grown on Printed Circuit Board for Extended-Gate Field-Effect Transistor pH Sensor

    NASA Astrophysics Data System (ADS)

    Van Thanh, Pham; Nhu, Le Thi Quynh; Mai, Hong Hanh; Tuyen, Nguyen Viet; Doanh, Sai Cong; Viet, Nguyen Canh; Kien, Do Trung

    2017-02-01

    Zinc oxide (ZnO) nanorods (NRs) were grown directly on printed circuit boards with a 35-μm-thick copper layer using a seedless galvanic-cell hydrothermal process. The hexagonal structure of the synthesized ZnO NRs was observed by scanning electron microscopy. The microstructural characteristics of the as-grown ZnO NRs were investigated by x-ray diffraction analysis, revealing preferred (002) growth direction. Raman and photoluminescence spectra confirmed the high crystalline quality of the ZnO NRs. As-grown ZnO NRs were then grown for 7 h using the galvanic effect for use as the pH membrane of an extended-gate field-effect transistor pH sensor (pH-EGFET). The current-voltage characteristics showed sensitivity of 15.4 mV/pH and 0.26 (μA)1/2/pH in the linear and saturated region, respectively. Due to their cost effectiveness, low-temperature processing, and ease of fabrication, such devices are potential candidates for use as flexible, low-cost, disposable biosensors.

  7. Study of the transference rules for bromine in waste printed circuit boards during microwave-induced pyrolysis.

    PubMed

    Sun, Jing; Wang, Wenlong; Liu, Zhen; Ma, Chunyuan

    2011-05-01

    The production of waste printed circuit boards (WPCBs) has drawn increasing global concern, especially because the high bromine (Br) content (5-15%) places obstacles in the way of simple disposal techniques. Microwave-induced pyrolysis of WPCBs provides a promising way to dispose of these hazardous and resource-filled wastes. The transference rules for Br during microwave-induced pyrolysis have been investigated experimentally. It was found that the microwave energy could be used more efficiently to accelerate the heating rate and improve the final pyrolysis temperature by adding some activated carbon (AC) as microwave absorbents. The high temperature and rapid pyrolysis process promoted the yields of gaseous products and the decomposition of brominated compounds into hydrogen bromide and then benefited the capture of Br and the debromination of byproducts. The application of a calcium carbonate (CaCO3) layer overhead led to over 95% debromination of the liquid products and over 50% capture of the total Br. It can be concluded that the presented method is suitable for the control of Br transference in the recycling of WPCBs. This method can also be extended to the disposal of the electronic scraps.

  8. Leaching behavior of copper from waste printed circuit boards with Brønsted acidic ionic liquid.

    PubMed

    Huang, Jinxiu; Chen, Mengjun; Chen, Haiyan; Chen, Shu; Sun, Quan

    2014-02-01

    In this work, a Brønsted acidic ionic liquid, 1-butyl-3-methyl-imidazolium hydrogen sulfate ([bmim]HSO4), was used to leach copper from waste printed circuit boards (WPCBs, mounted with electronic components) for the first time, and the leaching behavior of copper was discussed in detail. The results showed that after the pre-treatment, the metal distributions were different with the particle size: Cu, Zn and Al increased with the increasing particle size; while Ni, Sn and Pb were in the contrary. And the particle size has significant influence on copper leaching rate. Copper leaching rate was higher than 99%, almost 100%, when 1g WPCBs powder was leached under the optimum conditions: particle size of 0.1-0.25 mm, 25 mL 80% (v/v) ionic liquid, 10 mL 30% hydrogen peroxide, solid/liquid ratio of 1/25, 70°C and 2h. Copper leaching by [bmim]HSO4 can be modeled with the shrinking core model, controlled by diffusion through a solid product layer, and the kinetic apparent activation energy has been calculated to be 25.36 kJ/mol. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Application of vacuum metallurgy to separate pure metal from mixed metallic particles of crushed waste printed circuit board scraps.

    PubMed

    Zhan, Lu; Xu, Zhenming

    2008-10-15

    The principle of separating pure metal from mixed metallic particles (MMPs) byvacuum metallurgy is that the vapor pressures of various metals at the same temperature are different As a result, the metal with high vapor pressure and low boiling point can be separated from the mixed metals through distillation or sublimation, and then it can be recycled through condensation under a certain condition. The vacuum metallurgy separation (VMS) of MMPs of crushed waste printed circuit boards (WPCBs) has been studied in this paper. Theoretical analyses show that the MMPs (copper, zinc, bismuth, lead, and indium, for example) can be separated by vacuum metallurgy. The copper particles (0.15-0.20 mm) and zinc particles (<0.30 mm) were chosen to simulate the MMPs of crushed WPCBs. Experimental results show that the separated efficiency of zinc in the copper-rich particles achieves 96.19 wt % when the vacuum pressure is 0.01-0.10 Pa, the heating temperature is 1123 K, and the heating time is 105 min. Under this operation condition, the separated efficiency of zinc in the copper-rich particles from crushed WPCBs achieves 97.00 wt % and the copper purity increases from 90.68 to 99.84 wt %.

  10. Performance of the heavy fraction of pyrolysis oil derived from waste printed circuit boards in modifying asphalt.

    PubMed

    Yang, Fan; Sun, Shuiyu; Zhong, Sheng; Li, Shenyong; Wang, Yi; Wu, Jiaqi

    2013-09-15

    The focus of this research was the development of efficient and affordable asphalt modifiers. Pyrolysis oil was produced as a byproduct from the pyrolysis of waste printed circuit boards (WPCBs). The high boiling point fraction was separated from the pyrolysis oil through distillation and is referred to as the heavy fraction of pyrolysis oil (HFPO). The HFPO was tested as an asphalt modifier. Three asphalt modifiers were tested: HFPO; styrene-butadiene rubber (SBR); and HFPO + SBR (1:1). The physical properties and road performance of the three modified asphalts were measured and evaluated. The results have shown that when the amount of modifier was less than 10%, the HFPO modified asphalt had the highest softening point of the three. The dynamic stability (DS) and water resistance of the asphalt mixture with the HFPO modified asphalt was 10,161 cycles/mm and 87.2%, respectively. The DS was much larger than for the HFPO + SBR and SBR modified asphalt mixtures. These results indicate that using HFPO as an asphalt modifier has significant benefits not only for road engineering but also for resource recycling. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Production and characterization of polypropylene composites filled with glass fibre recycled from pyrolysed waste printed circuit boards.

    PubMed

    Li, Shenyong; Sun, Shuiyu; Liang, Haifeng; Zhong, Sheng; Yang, Fan

    2014-01-01

    Waste printed circuit boards (WPCBs) are composed of nearly 70% non-metals, which are generally recycled as low-value filling materials or even directly dumped in landfills. In this study, polypropylene (PP) composites reinforced by recycled pure glass fibres (RGF) from pyrolysed WPCBs were successfully produced. The manufacturing process, mechanical properties and thermal behaviour of the composites were investigated. The results showed that the appropriate addition of RGF in the composites can significantly improve the mechanical properties and thermal behaviour. When the added content of RGF was 30%, the maximum increment of tensile strength, impact strength, flexural strength and flexural modulus of the glass fibre (GF)/PP composites are 25.93%, 41.38%, 31.16% and 68.42%, respectively, and the vicat softening temperature could rise by 4.6°C. Furthermore, leaching of the GF/PP composites was also investigated. The GF/PP composites exhibited high performance and non-toxicity, offering a promising method to recycle RGF from pyrolysed WPCBs with high-value applications.

  12. Occurrences and inventories of heavy metals and brominated flame retardants in wastes from printed circuit board production.

    PubMed

    Zhou, Xiaoyu; Guo, Jie; Zhang, Wei; Zhou, Peng; Deng, Jingjing; Lin, Kuangfei

    2014-09-01

    Pollutants including heavy metals and brominated flame retardant were detected in 10 types of production wastes from a typical printed circuit board manufacturing plant, and their inventories were estimated. Rinsing water from etching process had the highest concentrations of copper (665.51 mg/L), lead (1.02 mg/L), nickel (3.60 mg/L), chromium (0.97 mg/L), and tin (1.79 mg/L). Powdered solid waste (SW) from the cut lamination process contained the highest tetrabromobisphenol-A (TBBPA) levels (49.86 mg/kg). Polybrominated diphenyl ethers (PBDEs) were absent in this plant, in agreement with the international regulations of PBDE phase out. The pollutant inventories in the wastes exhibited in the order of copper > > zinc > tin ≈ nickel > lead > chromium > > TBBPA. The potential environmental impact of pollutants in SW during production and disposal were further investigated. A high partitioning of pollutant concentration between the total suspended particle and SW (-0.10 < log K TS < 2.12) was observed for most pollutants, indicating the emission pathway from SW to the airborne atmosphere in the workshop. Although SW met the toxicity characteristic leaching procedure, drilling powder with the smallest particle diameter still showed high leachabilities of lead and tin which may lead to a negative environmental impact during disposal.

  13. An Overview of Surface Finishes and Their Role in Printed Circuit Board Solderability and Solder Joint Performance

    SciTech Connect

    Vianco, P.T.

    1998-10-15

    A overview has been presented on the topic of alternative surface finishes for package I/Os and circuit board features. Aspects of processability and solder joint reliability were described for the following coatings: baseline hot-dipped, plated, and plated-and-fused 100Sn and Sn-Pb coatings; Ni/Au; Pd, Ni/Pd, and Ni/Pd/Au finishes; and the recently marketed immersion Ag coatings. The Ni/Au coatings appear to provide the all-around best option in terms of solderability protection and wire bondability. Nickel/Pal ftishes offer a slightly reduced level of performance in these areas that is most likely due to variable Pd surface conditions. It is necessmy to minimize dissolved Au or Pd contents in the solder material to prevent solder joint embrittlement. Ancillary aspects that included thickness measurement techniques; the importance of finish compatibility with conformal coatings and conductive adhesives; and the need for alternative finishes for the processing of non-Pb bearing solders were discussed.

  14. Direct extraction of palladium and silver from waste printed circuit boards powder by supercritical fluids oxidation-extraction process.

    PubMed

    Liu, Kang; Zhang, Zhiyuan; Zhang, Fu-Shen

    2016-11-15

    The current study was carried out to develop an environmental benign process for direct recovery of palladium (Pd) and silver (Ag) from waste printed circuit boards (PCBs) powder. The process ingeniously combined supercritical water oxidation (SCWO) and supercritical carbon dioxide (Sc-CO2) extraction techniques. SCWO treatment could effectively enrich Pd and Ag by degrading non-metallic component, and a precious metal concentrate (PMC) could be obtained, in which the enrichment factors of Pd and Ag reached 5.3 and 4.8, respectively. In the second stage, more than 93.7% Pd and 96.4% Ag could be extracted from PMC by Sc-CO2 modified with acetone and KI-I2 under optimum conditions. Mechanism study indicated that Pd and Ag extraction by Sc-CO2 was a complicated physiochemical process, involving oxidation, complexation, anion exchange, mass transfer and migration approaches. Accordingly, this study established a benign and effective process for selective recovery of dispersal precious metals from waste materials. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Investigation of the influence of inert and oxidizing atmospheres on the efficiency of decomposition of waste printed circuit boards (WPCBs)

    NASA Astrophysics Data System (ADS)

    Kumari, Anjan; Jha, Manis Kumar; Singh, Rajendra Prasad; Ranganathan, S.

    2017-04-01

    Thermo-gravimetry was used for studying the influence of the furnace atmosphere during the pyrolysis waste circuit boards (WPCBs). Pyrolysis in argon atmosphere resulted in a continuous decrease of mass of the sample. Rapid mass loss occurred at about 573 K. Heating the WPCBs in air and oxygen atmospheres resulted in an increase in the mass of the sample in the early stages until rapid mass loss occurred at about 573 K. When pyrolysis of larger sample mass (about 5 g each) was carried out in tubular furnace, about 20.43 % mass loss was observed during the pyrolysis of WPCBs in a flowing stream of argon at 548 K during a period of 4 min. On the other hand, a maximum of about 2.26 % mass loss was recorded when the WPCBs were heated at about 600 K for the same time interval in the still air. The mass transfer during the pyrolysis of WPCBs in flowing stream of inert gas was also modeled. It is found that controlling the flow rate of inert gas and the geometry of the equipment can enhance the rate of mass loss significantly.

  16. Recovery of copper and lead from waste printed circuit boards by supercritical water oxidation combined with electrokinetic process.

    PubMed

    Xiu, Fu-Rong; Zhang, Fu-Shen

    2009-06-15

    An effective and benign process for copper and lead recovery from waste printed circuit boards (PCBs) was developed. In the process, the PCBs was pre-treated in supercritical water, then subjected to electrokinetic (EK) process. Experimental results showed that supercritical water oxidation (SCWO) process was strong enough to decompose the organic compounds of PCBs, and XRD spectra indicated that copper and lead were oxidized into CuO, Cu(2)O and beta-PbO(2) in the process. The optimum SCWO treatment conditions were 60 min, 713 K, 30 MPa, and EK treatment time, constant current density were 11h, 20 mA cm(-2), respectively. The recovery percentages of copper and lead under optimum SCWO+EK treatment conditions were around 84.2% and 89.4%, respectively. In the optimized EK treatment, 74% of Cu was recovered as a deposit on the cathode with a purity of 97.6%, while Pb was recovered as concentrated solutions in either anode (23.1%) or cathode (66.3%) compartments but little was deposited on the electrodes. It is believed that the process is effective and practical for Cu and Pb recovery from waste electric and electronic equipments.

  17. Electrokinetic recovery of Cd, Cr, As, Ni, Zn and Mn from waste printed circuit boards: effect of assisting agents.

    PubMed

    Xiu, Fu-Rong; Zhang, Fu-Shen

    2009-10-15

    The printed circuit boards (PCBs) contains large number of heavy metal such as Cd, Cr, As, Ni, Zn and Mn. In this study, the use of electrokinetic (EK) treatment with different assisting agents has been investigated to recover the heavy metals from waste PCBs, and the effectiveness of different assisting agents (HNO(3), HCl, citric acid) was evaluated. The PCBs were first pre-treated by supercritical water oxidation (SCWO) process, then subjected to EK process. The heavy metal speciation, migration and recovery efficiency in the presence of different assisting agents during EK process were discussed. The mass loss of Cd, Cr, As and Zn during the SCWO process was negligible, but approximately 52% of Ni and 56% of Mn were lost in such a process. Experimental results showed that different assisting agents have significant effect on the behavior and recovery efficiency of different heavy metals. HCl was highly efficient for the recovery of Cd in waste PCBs due to the low pH and the stable complexation of Cl(-). Citric acid was highly efficient for the recovery of Cr, Zn and Mn. HNO(3) was low efficient for recovery of most heavy metals except for Ni.

  18. Zinc Oxide Nanorods Grown on Printed Circuit Board for Extended-Gate Field-Effect Transistor pH Sensor

    NASA Astrophysics Data System (ADS)

    Van Thanh, Pham; Nhu, Le Thi Quynh; Mai, Hong Hanh; Tuyen, Nguyen Viet; Doanh, Sai Cong; Viet, Nguyen Canh; Kien, Do Trung

    2017-06-01

    Zinc oxide (ZnO) nanorods (NRs) were grown directly on printed circuit boards with a 35- μm-thick copper layer using a seedless galvanic-cell hydrothermal process. The hexagonal structure of the synthesized ZnO NRs was observed by scanning electron microscopy. The microstructural characteristics of the as-grown ZnO NRs were investigated by x-ray diffraction analysis, revealing preferred (002) growth direction. Raman and photoluminescence spectra confirmed the high crystalline quality of the ZnO NRs. As-grown ZnO NRs were then grown for 7 h using the galvanic effect for use as the pH membrane of an extended-gate field-effect transistor pH sensor (pH-EGFET). The current-voltage characteristics showed sensitivity of 15.4 mV/pH and 0.26 ( μA)1/2/pH in the linear and saturated region, respectively. Due to their cost effectiveness, low-temperature processing, and ease of fabrication, such devices are potential candidates for use as flexible, low-cost, disposable biosensors.

  19. A novel recovery method of copper from waste printed circuit boards by supercritical methanol process: Preparation of ultrafine copper materials.

    PubMed

    Xiu, Fu-Rong; Weng, Huiwei; Qi, Yingying; Yu, Gending; Zhang, Zhigang; Zhang, Fu-Shen; Chen, Mengjun

    2017-02-01

    In this study, supercritical methanol (SCM) process was successfully used for the preparation of ultrafine copper materials from waste printed circuit boards (PCBs) after nitric acid pretreatment. Waste PCBs were pretreated twice in nitric acid. Sn and Pb were recovered by the first nitric acid pretreatment. The leach liquor with a high concentration of copper ions after the second nitric acid leaching was subjected to SCM process. The mixture of Cu and Cu2O with poor uniformity of particle size was formed due to the effect of ferric iron contained in the leach liquor of waste PCBs, while more uniform and spherical Cu particles with high monodispersity and smaller size could be prepared after the removal of Fe. The size of Cu particles increased obviously with the decline of SCM temperature, and particles became highly aggregated when the reaction temperature decreased to 300°C. The size of Cu particles decreased markedly with the decrease of initial concentration of copper ion in the leach liquor of waste PCBs. It is believed that the process developed in this study is simple and practical for the preparation of ultrafine copper materials from waste PCBs with the aim of recycling these waste resources as a high value-added product. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Determination of the potential gold electrowinning from an ammoniacal thiosulphate solution applied to recycling of printed circuit board scraps.

    PubMed

    Kasper, Angela C; Carrillo Abad, Jordi; García Gabaldón, Montserrat; Veit, Hugo M; Pérez Herranz, Valentín

    2016-01-01

    The use of electrochemical techniques in the selective recovery of gold from a solution containing thiosulphate, ammonia, and copper, obtained from the leaching of printed circuit boards from mobile phones using ammoniacal thiosulphate, are shown in this work. First, cyclic voltammetry tests were performed to determine the potential of electrodeposition of gold and copper, and then, electrowinning tests at different potentials for checking the rates of recovery of these metals were performed. The results of the cyclic voltammetry show that copper deposition occurs at potentials more negative than -600 mV (Ag/AgCl), whereas the gold deposition can be performed at potentials more positives than -600 mV (Ag/AgCl). The results of electrowinning show that 99% of the gold present in solutions containing thiosulphate and copper can be selectively recovered in a potential range between -400 mV (vs Ag/AgCl) and -500 mV (vs Ag/AgCl). Furthermore, 99% of copper can be recovered in potentials more negative than -700 mV (vs Ag/AgCl).

  1. Reduction Characteristics of FM-Band Cross-Talks between Two Parallel Signal Traces on Printed Circuit Boards for Vehicles

    NASA Astrophysics Data System (ADS)

    Maeno, Tsuyoshi; Ueyama, Hiroya; Iida, Michihira; Fujiwara, Osamu

    It is well known that electromagnetic disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring-harnesses from vehicle-mounted printed circuit boards (PCBs) with common ground patterns with slits. To suppress the noise current outflows from the PCBs of this kind, we previously measured noise current outflows from simple two-layer PCBs having two parallel signal traces and different ground patterns with/without slits, which revealed that making slits with open ends on the ground patterns in parallel with the traces can reduce the conducted noise currents. In the present study, with the FDTD simulation, we investigated reduction characteristics of the FM-band cross-talk noise levels between two parallel signal traces for eighteen PCBs, which have different ground patterns with/without slits parallel to the traces and dielectric layers with different thickness. As a result, we found that the cross-talk reduction effect due to slits is obtained by 3.6-5.3dB, while the cross-talks between signal traces are reduced in inverse proportion to the square of the dielectric-layer thickness and in proportion to the square of the trace interval and, which can quantitatively be explained from an inductive coupling theory.

  2. Novel Application of Glass Fibers Recovered From Waste Printed Circuit Boards as Sound and Thermal Insulation Material

    NASA Astrophysics Data System (ADS)

    Sun, Zhixing; Shen, Zhigang; Ma, Shulin; Zhang, Xiaojing

    2013-10-01

    The aim of this study is to investigate the feasibility of using glass fibers, a recycled material from waste printed circuit boards (WPCB), as sound absorption and thermal insulation material. Glass fibers were obtained through a fluidized-bed recycling process. Acoustic properties of the recovered glass fibers (RGF) were measured and compared with some commercial sound absorbing materials, such as expanded perlite (EP), expanded vermiculite (EV), and commercial glass fiber. Results show that RGF have good sound absorption ability over the whole tested frequency range (100-6400 Hz). The average sound absorption coefficient of RGF is 0.86, which is prior to those of EP (0.81) and EV (0.73). Noise reduction coefficient analysis indicates that the absorption ability of RGF can meet the requirement of II rating for sound absorbing material according to national standard. The thermal insulation results show that RGF has a fair low thermal conductivity (0.046 W/m K), which is comparable to those of some insulation materials (i.e., EV, EP, and rock wool). Besides, an empirical dependence of thermal conductivity on material temperature was determined for RGF. All the results showed that the reuse of RGF for sound and thermal insulation material provided a promising way for recycling WPCB and obtaining high beneficial products.

  3. Recovery of metals from waste printed circuit boards by supercritical water pre-treatment combined with acid leaching process.

    PubMed

    Xiu, Fu-Rong; Qi, Yingying; Zhang, Fu-Shen

    2013-05-01

    Waste printed circuit boards (PCBs) contain a large number of metals such as Cu, Sn, Pb, Cd, Cr, Zn, and Mn. In this work, an efficient and environmentally friendly process for metals recovery from waste PCBs by supercritical water (SCW) pre-treatment combined with acid leaching was developed. In the proposed process, waste PCBs were pre-treated by SCW, then the separated solid phase product with concentrated metals was subjected to an acid leaching process for metals recovery. The effect of SCW pre-treatment on the recovery of different metals from waste PCBs was investigated. Two methods of SCW pre-treatment were studied: supercritical water oxidation (SCWO) and supercritical water depolymerization (SCWD). Experimental results indicated that SCWO and SCWD pre-treatment had significant effect on the recovery of different metals. SCWO pre-treatment was highly efficient for enhancing the recovery of Cu and Pb, and the recovery efficiency increased significantly with increasing pre-treatment temperature. The recovery efficiency of Cu and Pb for SCWO pre-treatment at 420°C was 99.8% and 80%, respectively, whereas most of the Sn and Cr were immobilized in the residue. The recovery of all studied metals was enhanced by SCWD pre-treatment and increased along with pre-treatment temperature. Up to 90% of Sn, Zn, Cr, Cd, and Mn could be recovered for SCWD pre-treatment at 440°C. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Design of drive circuit of laser diode

    NASA Astrophysics Data System (ADS)

    Ran, Yingying; Huang, Xuegong; Xu, Xiaobin

    2016-10-01

    Aiming at the difficult problem of high precision frequency stabilization of semiconductor laser diode, the laser frequency control is realized through the design of the semiconductor drive system. Above all, the relationship between the emission frequency and the temperature of LD is derived theoretically. Then the temperature corresponding to the stable frequency is obtained. According to the desired temperature stability of LD, temperature control system is designed, which is composed of a temperature setting circuit, temperature gathering circuit, the temperature display circuit, analog PID control circuit and a semiconductor refrigerator control circuit module. By sampling technology, voltage of platinum resistance is acquired, and the converted temperature is display on liquid crystal display. PID analog control circuit controls speed stability and precision of temperature control. The constant current source circuit is designed to provide the reference voltage by a voltage stabilizing chip, which is buffered by an operational amplifier. It is connected with the MOSFET to drive the semiconductor laser to provide stable current for the semiconductor laser. PCB circuit board was finished and the experimental was justified. The experimental results show that: the design of the temperature control system could achieve the goal of temperature monitoring. Meanwhile, temperature can be stabilized at 40°C +/- 0.1°C. The output voltage of the constant current source is 2 V. The current is 35 mA.

  5. Surface grafting of epoxy polymer on CB to improve its dispersion to be the filler of resistive ink for PCB

    NASA Astrophysics Data System (ADS)

    Zhou, Guoyun; Xu, Xiaolan; Wang, Shouxu; He, Xuemei; He, Wei; Su, Xinhong; Wong, Ching Ping

    In this paper, we report a novel and efficient method of promoting the dispersing uniformity of carbon black (CB) in epoxy polymer substrate of PCB (printed circuit board) by chemical grafting. The reported method shows the promising capability in the application of advanced printable resistor ink. By taking advantage of the functionalized CB surfaces, the grafting reaction of epoxy polymer on CB particles was investigated with Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM) and thermo gravimetric analysis (TGA). FT-IR spectra evidenced the polymerization of epoxy resin with coupling agent and TEM investigation directly confirmed the polymerization occurred on CB surface. The polymerization occurred on the limited part of the CB surfaces to form a network-structure polymer to reside on the CB particles and hence greatly improved CB dispersion in ink as evidenced in ink-droplet spreading verification on glass and PCB resin substrates. On the other hand, the polymer grafting has limited effect on the increasing of the as-cured ink filled with the grafted CBs. Finally, the cross-section observation also confirmed the dispersion improvement and sheet resistance uniformity due to epoxy polymer grafting on PCB substrate, indicating the prospective candidate as embedded resistors for PCB.

  6. Copper sludge from printed circuit board production/recycling for ceramic materials: a quantitative analysis of copper transformation and immobilization.

    PubMed

    Tang, Yuanyuan; Lee, Po-Heng; Shih, Kaimin

    2013-08-06

    The fast development of electronic industries and stringent requirement of recycling waste electronics have produced a large amount of metal-containing waste sludge. This study developed a waste-to-resource strategy to beneficially use such metal-containing sludge from the production and recycling processes of printed circuit board (PCBs). To observe the metal incorporation mechanisms and phase transformation processes, mixtures of copper industrial waste sludge and kaolinite-based materials (kaolinite and mullite) were fired between 650 and 1250 °C for 3 h. The different copper-hosting phases were identified by powder X-ray diffraction (XRD) in the sintered products, and CuAl2O4 was found to be the predominant hosting phase throughout the reactions, regardless of the strong reduction potential of copper expected at high temperatures. The experimental results indicated that CuAl2O4 was generated more easily and in larger quantities at low-temperature processing when using the kaolinite precursor. Maximum copper transformations reached 86% and 97% for kaolinite and mullite systems, respectively, when sintering at 1000 °C. To monitor the stabilization effect after thermal process, prolonged leaching tests were carried out using acetic acid with an initial pH value of 2.9 to leach the sintered products for 20 days. The results demonstrated the decrease of copper leachability with the formation of CuAl2O4, despite different sintering behavior in kaolinite and mullite systems. This study clearly indicates spinel formation as the most crucial metal stabilization mechanism when sintering copper sludge with aluminosilicate materials, and suggests a promising and reliable technique for reusing metal-containing sludge as ceramic materials.

  7. Characterization and mechanical separation of metals from computer Printed Circuit Boards (PCBs) based on mineral processing methods.

    PubMed

    Sarvar, Mojtaba; Salarirad, Mohammad Mehdi; Shabani, Mohammad Amin

    2015-11-01

    In this paper, a novel mechanical process is proposed for enriching metal content of computer Printed Circuit Boards (PCBs). The PCBs are crushed and divided into three different size fractions namely: -0.59, +0.59 to 1.68 and +1.68 mm. Wet jigging and froth flotation methods are selected for metal enrichment. The coarse size fraction (+1.68 mm) is processed by jigging. The plastic free product is grinded and screened. The oversized product is separated as the first concentrate. It was rich of metal because the grinding process was selective. The undersized product is processed by froth flotation. Based on the obtained results, the middle size fraction (+0.59 to 1.68 mm) and the small size fraction (-0.59 mm) are processed by wet jigging and froth flotation respectively. The wet jigging process is optimized by investigating the effect of pulsation frequency and water flow rate. The results of examining the effect of particle size, solid to liquid ratio, conditioning time and using apolar collector showed that collectorless flotation is a promising method for separating nonmetals of PCBs. 95.6%, 97.5% and 85% of metal content of coarse size, middle size and small size fraction are recovered. The grades of obtained concentrates were 63.3%, 92.5% and 75% respectively. The total recovery is calculated as 95.64% and the grade of the final concentrate was 71.26%. Determining the grade of copper and gold in the final product reveals that 4.95% of copper and 24.46% of gold are lost during the concentration. The major part of the lost gold is accumulated in froth flotation tail.

  8. An assessment of alternatives for replacing Freon 113 in bench type electrical circuit board cleaning at Fermi National Accelerator Laboratory

    SciTech Connect

    Isakson, K.; Vessell, A.L.

    1994-07-01

    Fermilab is presently phasing out all solvents containing Freon-113 (CFC-113) as part of the continuing Waste Minimization Program. These solvents are used primarily in cleaning the flux off of electronic circuit boards after soldering, specifically in bench type work. Title VI of the Clean Air Act mandates a production phase-out for ozone depleting substances, like CFC-113, by the year 2000. Our study addresses this issue by evaluating and choosing alternative non-CFC solvents to replace the CFC-1 13 solvents at Fermilab. Several potential non-CFC cleaning solvents were tested. The evaluation took place in three parts: controlled experimental evaluation, chemical composition evaluation, and employee performed evaluation. First, we performed a controlled nine-step procedure with the potential solvents where each was evaluated in categories such as cleaning effectiveness, odor, residue, type of output and drying time. Next, we listed the chemical composition of each solvent. We noted which solvents contained hydrochlorofluorocarbons because they are targeted for phase-out in the future and will be recognized as interim solutions only. Finally, after preliminary testing, five solvents were chosen as the best options. These solvents were sent to be tested by Fermilab employees who use such materials. Their opinions are valuable not only because they are knowledgeable in this field, but also because they will be using the solvents chosen to replace the CFC-113 solvents. The results favored two ``best alternatives``: Safezone Solvent Flux Remover by Miller-Stephenson and E-Series CFC Free Flux-Off 2000 by Chemtech. Another possible solution also pursued is the no-clean solder option. In our study, we were not able to thoroughly investigate the many types of no-clean solders because of time and financial constraints. The testing that was done, however, showed that no-clean solder was a viable alternative in many cases.

  9. Leaching behavior of copper from waste printed circuit boards with Brønsted acidic ionic liquid

    SciTech Connect

    Huang, Jinxiu; Chen, Mengjun Chen, Haiyan; Chen, Shu; Sun, Quan

    2014-02-15

    Highlights: • A Brønsted acidic ILs was used to leach Cu from WPCBs for the first time. • The particle size of WPCBs has significant influence on Cu leaching rate. • Cu leaching rate was higher than 99% under the optimum leaching conditions. • The leaching process can be modeled with shrinking core model, and the E{sub a} was 25.36 kJ/mol. - Abstract: In this work, a Brønsted acidic ionic liquid, 1-butyl-3-methyl-imidazolium hydrogen sulfate ([bmim]HSO{sub 4}), was used to leach copper from waste printed circuit boards (WPCBs, mounted with electronic components) for the first time, and the leaching behavior of copper was discussed in detail. The results showed that after the pre-treatment, the metal distributions were different with the particle size: Cu, Zn and Al increased with the increasing particle size; while Ni, Sn and Pb were in the contrary. And the particle size has significant influence on copper leaching rate. Copper leaching rate was higher than 99%, almost 100%, when 1 g WPCBs powder was leached under the optimum conditions: particle size of 0.1–0.25 mm, 25 mL 80% (v/v) ionic liquid, 10 mL 30% hydrogen peroxide, solid/liquid ratio of 1/25, 70 °C and 2 h. Copper leaching by [bmim]HSO{sub 4} can be modeled with the shrinking core model, controlled by diffusion through a solid product layer, and the kinetic apparent activation energy has been calculated to be 25.36 kJ/mol.

  10. Temporal and spectral analysis of laser induced plasma in the ablation process of flexible printed circuit board

    NASA Astrophysics Data System (ADS)

    Ryoo, Hoon C.; Kim, Seok; Hahn, Jae W.

    2008-02-01

    Flexible printed circuit board (FPCB), consisting of copper sheets laminated onto non conductive film substrates with multiple structures, are core elements in electronics with their flexibility and capability of high density 3 dimensional wiring characteristics. In laser applied FPCB processing, a better understanding of the ablation mechanism leads to precision control of the depth processing especially by monitoring of the material transition layer. For this purpose, here we investigate the temporal and spectral behavior of the plasma plum generated on the single sided structure of FPCB using the technique of laser induced breakdown spectroscopy (LIBS). Using KrF excimer laser, the characteristic spectral emission lines of C II swan band at the wavelength of 516.5 nm and neutral copper at the wavelength range from 510 nm to 522 nm are acquired under ambient pressure in the ablation process of polyimide film and copper coated layer respectively. From a time delay from 50 ns to 4.05 μs from the beginning of the laser pulse, the temporal profiles of the spectral intensity are obtained in steps of 200 ns, which have a tendency of exponential decrease on both C II and neutral copper. In particular, we concentrate our attention on the temporal intensity behavior of the Bremsstrahlung continuum emission that decides the proper set of detection time window, by which the monitoring sensitivity of LIBS is determined. Finally, using the information of the temporal analysis for each molecular, atomic, and continuum emission, the transition layer between polyimide and copper film is distinguished by their characteristic peak information.

  11. Using the Fuzzy DEMATEL to Determine Environmental Performance: A Case of Printed Circuit Board Industry in Taiwan

    PubMed Central

    Tsai, Sang-Bing; Chien, Min-Fang; Xue, Youzhi; Li, Lei; Jiang, Xiaodong; Chen, Quan; Zhou, Jie; Wang, Lei

    2015-01-01

    The method by which high-technology product manufacturers balance profits and environmental performance is of crucial concern for governments and enterprises. To examine the environmental performance of manufacturers, the present study applied Fuzzy-DEMATEL model to examine environmental performance of the PCB industry in Taiwan. Fuzzy theory was employed to examine the environmental performance criteria of manufacturers and analyse fuzzy linguistics. The fuzzy-DEMATEL model was then employed to assess the direction and level of interaction between environmental performance criteria. The core environmental performance criteria which were critical for enhancing environmental performance of the PCB industry in Taiwan were identified and presented. The present study revealed that green design (a1), green material procurement (a2), and energy consumption (b3) constitute crucial reason criteria, the core criteria influencing other criteria, and the driving factors for resolving problems. PMID:26052710

  12. Using the Fuzzy DEMATEL to Determine Environmental Performance: A Case of Printed Circuit Board Industry in Taiwan.

    PubMed

    Tsai, Sang-Bing; Chien, Min-Fang; Xue, Youzhi; Li, Lei; Jiang, Xiaodong; Chen, Quan; Zhou, Jie; Wang, Lei

    2015-01-01

    The method by which high-technology product manufacturers balance profits and environmental performance is of crucial concern for governments and enterprises. To examine the environmental performance of manufacturers, the present study applied Fuzzy-DEMATEL model to examine environmental performance of the PCB industry in Taiwan. Fuzzy theory was employed to examine the environmental performance criteria of manufacturers and analyse fuzzy linguistics. The fuzzy-DEMATEL model was then employed to assess the direction and level of interaction between environmental performance criteria. The core environmental performance criteria which were critical for enhancing environmental performance of the PCB industry in Taiwan were identified and presented. The present study revealed that green design (a1), green material procurement (a2), and energy consumption (b3) constitute crucial reason criteria, the core criteria influencing other criteria, and the driving factors for resolving problems.

  13. PCB storage requirements

    SciTech Connect

    1994-12-01

    Polychlorinated biphenyls (PCBs) are a class of organic chemicals that had become widely used in industrial applications due to their practical physical and chemical properties. Historical uses of PCBs include dielectric fluids (used in utility transformers, capacitors, etc.), hydraulic fluids, and other applications requiring stable, fire-retardant materials. Due to findings that PCBs may cause adverse health effects and due to their persistence and accumulation in the environment, the Toxic Substances Control Act (TSCA), enacted on october 11, 1976, banned the manufacture of PCBs after 1978 [Section 6(e)]. The first PCB regulations, promulgated at 40 CFR Part 761, were finalized on February 17, 1978. These PCB regulations include requirements specifying disposal methods and marking (labeling) procedures, and controlling PCB use. To assist the Department of Energy (DOE) in its efforts to comply with the TSCA statute and implementing regulations, the Office of Environmental Guidance has prepared the document ``Guidance on the Management of Polychlorinated Biphenyls (PCBs).`` That document explains the requirements specified in the statute and regulations for managing PCBs, including PCB use, storage, transport, and disposal. The requirements specified at 40 CFR Part 761.65 require most PCB wastes to be stored in a facility that meets the specifications of that section. Additionally, the regulations include rules concerning time limits for PCBs and PCB Items in storage, rules concerning leaking electrical equipment, and rules concerning types of containers used to store PCBs and PCB Items. This Information Brief supplements the PCB guidance document by responding to common questions concerning storage requirements for PCBs. It is one of a series of Information Briefs pertinent to PCB management issues.

  14. Anvil for Flaring PCB Guide Pins

    NASA Technical Reports Server (NTRS)

    Winn, E.; Turner, R.

    1985-01-01

    Spring-loaded anvil results in fewer fractured pins. New anvil for flaring guide pins in printed-circuit boards absorbs approximately 80 percent of press force. As result fewer pins damaged, and work output of flaring press greatly increased.

  15. Evaluating industrial toxic waste reduction: Using publicly reported data to assess changes in metal finishing and circuit board printing, California, USA

    SciTech Connect

    Duke, L.D.; Masek, B.

    1997-12-31

    Waste reduction actions reported by facilities of two industrial sectors in one geographic region are evaluated using hazardous waste generator reports filed under the Biennial Reporting System (BRS) for activities in 1991 and 1993. The goal is to attempt to identify changes in industrial toxic waste generation attributable to pollution prevention activities. Aggregate statistics for industrial hazardous wastes show cumulative reduction in volume and weight of waste regulated under the US Resource Conservation and Recovery Act (RCRA) and analogous state-level rules. However, it is not clear to what extent the mass of toxic materials in waste streams is reduced, or to what degree waste reduction is produced by source reduction and pollution prevention rather than shifting some pollutants to other discharge routes not subject to RCRA. Quantitative estimates of reduction in mass of toxic materials are not supported by currently available publicly reported information. This paper instead evaluates the kinds of waste reduction reported by industrial facilities, assesses the degree to which pollution prevention is widely practiced, and identifies types of source reduction or other waste management measures most widely implemented. BRS reports by samples of facilities of the metal plating industry and the printed circuit board industry, drawn from the San Francisco Bay Area, California, show a large number of facilities reporting implementing waste reduction measures, with one or more actions implemented by about 45% to 65% of metal plating facilities and about 55% of circuit board printing facilities. The most widely-implemented measures were within the Housekeeping/Maintenance category, suggesting that all simple, low-cost potential measures had not been exhausted as recently as 1993. The Materials Substitution category was important in the circuit board printing industry, implemented by 37% of sample facilities in 1993.

  16. Data Mining Approaches for Modeling Complex Electronic Circuit Design Activities

    SciTech Connect

    Kwon, Yongjin; Omitaomu, Olufemi A; Wang, Gi-Nam

    2008-01-01

    A printed circuit board (PCB) is an essential part of modern electronic circuits. It is made of a flat panel of insulating materials with patterned copper foils that act as electric pathways for various components such as ICs, diodes, capacitors, resistors, and coils. The size of PCBs has been shrinking over the years, while the number of components mounted on these boards has increased considerably. This trend makes the design and fabrication of PCBs ever more difficult. At the beginning of design cycles, it is important to estimate the time to complete the steps required accurately, based on many factors such as the required parts, approximate board size and shape, and a rough sketch of schematics. Current approach uses multiple linear regression (MLR) technique for time and cost estimations. However, the need for accurate predictive models continues to grow as the technology becomes more advanced. In this paper, we analyze a large volume of historical PCB design data, extract some important variables, and develop predictive models based on the extracted variables using a data mining approach. The data mining approach uses an adaptive support vector regression (ASVR) technique; the benchmark model used is the MLR technique currently being used in the industry. The strengths of SVR for this data include its ability to represent data in high-dimensional space through kernel functions. The computational results show that a data mining approach is a better prediction technique for this data. Our approach reduces computation time and enhances the practical applications of the SVR technique.

  17. PCB recordkeeping and reporting

    SciTech Connect

    1994-12-01

    Polychlorinated biphenyls (PCBs) are a class of organic chemicals that had become widely used in industrial applications due to their practical physical and chemical properties. Historical uses of PCBs include dielectric fluids (used in utility transformers, capacitors, etc.), hydraulic fluids, and other applications requiring stable, fire-retardant materials. Due to findings that PCBs may cause adverse health effects and due to their persistence and accumulation in the environment, the Toxic Substances Control Act (TSCA), enacted on October 11, 1976, banned the manufacture of PCBs after 1978 [Section 6(e)]. The first PCB regulations, promulgated at 40 CFR Part 761, were finalized on February 17, 1978. These PCB regulations include requirements specifying disposal methods and marking (labeling) procedures, and controlling PCB use. To assist the Department of Energy (DOE) in its efforts to comply with the TSCA statute and implementing regulations, the Office of Environmental Guidance has prepared the document ``Guidance on the Management of Polychlorinated Biphenyls (PCBs).`` That document explains the requirements specified in the statute and regulations for managing PCBs including PCB use, storage, transport, and disposal. All generators, disposers, and storers of PCB waste must comply with the recordkeeping and reporting requirements found at 40 CFR 761.180. The regulations include directions for writing and maintaining annual records and annual document logs and for preparing annual reports, exception reports, manifest discrepancy reports, and unmanifested waste reports. This Information Brief supplements the PCB guidance document by responding to common questions concerning recordkeeping and reporting requirements for PCBs. It is one of a series of Information Briefs pertinent to PCB management issues.

  18. PCB biohalogenation under anaerobic conditions

    SciTech Connect

    Gauger, W.K.; McCue, J.J.

    1990-01-01

    The Institute of Gas Technology (IGT) is conducting research on the biodehalogenation of polychlorinated biphenyls (PCB's) under anoxic conditions. Reductive dechlorination of PCB's has been observed in treatments inoculated with Hudson River sediments. Differences in gas chromatograms between time 0 and 4-month incubations indicate pattern shifts of the PCB homologs that constitute Aroclor 1242 from highly chlorinated to lesser chlorinated congeners. Changes in distribution patterns of PCB homologs were also evident. PCB homologs containing 4, 5, 6, and 7 chlorine atoms were shown to decrease over the incubation period, whereas PCB homologs containing 2 and 3 chlorines increased in concentration. 10 refs., 5 figs., 1 tab.

  19. High-efficiency thin and compact concentrator photovoltaics using micro-solar cells with via-holes sandwiched between thin lens-array and circuit board

    NASA Astrophysics Data System (ADS)

    Itou, Akihiro; Asano, Tetsuya; Inoue, Daijiro; Arase, Hidekazu; Matsushita, Akio; Hayashi, Nobuhiko; Futakuchi, Ryutaro; Inoue, Kazuo; Yamamoto, Masaki; Fujii, Eiji; Nakagawa, Tohru; Anda, Yoshiharu; Ishida, Hidetoshi; Ueda, Tetsuzo; Fidaner, Onur; Wiemer, Michael; Ueda, Daisuke

    2014-01-01

    We have developed a compact concentrator photovoltaic (CPV) module that comprises micro-solar cells with an area of ≈0.6 × 0.6 mm2 sandwiched between a 20-mm-thick lens array and a 1-mm-thick circuit board with no air gap. To establish electrical connections between the circuit board and the micro-solar cells, we developed a micro-solar cell with positive and negative electrodes on the lower face of the cell. In this study, we demonstrated the photovoltaic performance of the micro-solar cell closely approaches that of the standard solar cell measuring ≈5 × 5 mm2 commonly used in conventional CPVs under concentrated illumination. Our study showed that the negative effect on PV performance of perimeter carrier recombination in the micro-solar cell was insignificant under concentrated illumination. Finally, we assembled our micro-solar cells into a CPV module and achieved the module energy conversion efficiency of 34.7% under outdoor solar illumination.

  20. Ultra-Wideband Array in PCB for Millimeter-Wave 5G and ISM

    NASA Technical Reports Server (NTRS)

    Novak, Markus H.; Volakis, John L.; Miranda, Felix A.

    2017-01-01

    Growing mobile data consumption has prompted the exploration of the millimeter-wave spectrum for large bandwidth, high speed communications. However, the allocated bands are spread across a wide swath of spectrum: Fifth generation mobile architecture (5G): 28, 38, 39, 6471 GHz; Industrial, Scientific, and Medical bands (ISM): 24, 60 GHz. Moreover, high gain phased arrays are required to overcome the significant path loss associated with these frequencies. Further, it is necessary to incorporate several of these applications in a single, small size and low cost platform. To this end, we have developed a scanning, Ultra-Wideband (UWB) array which covers all 5G, ISM, and other mm-W bands from 2472 GHz. Critically, this is accomplished using mass-production Printed Circuit Board (PCB) fabrication. The results of this work are presented in this poster.

  1. Impact of surface roughness on Dielectrophoretically assisted concentration of microorganisms over PCB based platforms.

    PubMed

    Bhatt, Geeta; Kant, Rishi; Mishra, Keerti; Yadav, Kuldeep; Singh, Deepak; Gurunath, Ramanathan; Bhattacharya, Shantanu

    2017-06-01

    This article presents a PCB based microfluidic platform for performing a dielectrophoretic capture of live microorganisms over inter-digitated electrodes buried under layers of different surface roughness values. Although dielectrophoresis has been extensively studied earlier over silicon and polymer surfaces with printed electrodes the issue of surface roughness particularly in case of buried electrodes has been seldom investigated. We have addressed this issue through a layer of spin coated PDMS (of various surface roughness) that is used to cover the printed electrodes over a printed circuit board. The roughness in the PDMS layer is generally defined by the roughness of the FR4 base which houses the printed electrodes as well as other structures. Possibilities arising out of COMSOL simulations have been well validated experimentally in this work.

  2. PCB/polymer based micro-fluidic system for NMR spectroscopy for nanoliters sample volume.

    PubMed

    Pasquet, Guillaume; Chateaux, Jean-François; Deman, Anne-Laure; Fenet, Bernard; Morin, Pierre

    2007-01-01

    In this work, we report on the realization of an innovating micro system for NMR spectroscopy on small sample volume (30-100 nL). We propose a micro system based on Printed Circuit Board (PCB) technology for the NMR probe associated to a micro fluidic system made with polymer (COC). The comparison of several samples during the same NMR experiments could provide more precise information. In that context, we have realized a micro-fluidic system with two cavities, each cavity presenting a volume of 37 nl. The fabrication process is described, and first results are reported. The tight sealing of the micro-fluidic system has been demonstrated and preliminary NMR experiment results are presented.

  3. Surface plasma preionization produced on a specially patterned PCB and its application in a pulsed CO2 laser

    NASA Astrophysics Data System (ADS)

    Ghorbanzadeh, Atamalek; Pakmanesh, Nahid; Rastegari, Ali; Abdolghader, Pedram; Feizollah, Peyman; Siadati, Neda

    2016-04-01

    The performance of an atmospheric pressure pulsed carbon dioxide laser employing surface plasma preionization, produced on a specially patterned printed circuit board (PCB), is reported. The surface plasma is formed due to many tiny plasma channels produced in millimeter sized open circular gaps, made by lithography on one side of PCB. The preionizing plasma is mostly consisted of corona or glow stage and transition to spark one hardly occurs. This type of preionization allows a maximum of 220 J/l energy deposition into the main plasma, while up scaling is yet possible by more optimization of PCB and the pattern. The laser output energy of 1.2 J per pulse with overall efficiency of 7% has been obtained with gas mixture of He:CO2:N2=3:1:1. This type of surface plasma preionization is specifically appropriate for very large volumes and high pressures, where the conventional UV emitting preionizations like spark arrays or corona are not effective.

  4. Flexible circuits with integrated switches for robotic shape sensing

    NASA Astrophysics Data System (ADS)

    Harnett, C. K.

    2016-05-01

    Digital switches are commonly used for detecting surface contact and limb-position limits in robotics. The typical momentary-contact digital switch is a mechanical device made from metal springs, designed to connect with a rigid printed circuit board (PCB). However, flexible printed circuits are taking over from the rigid PCB in robotics because the circuits can bend while carrying signals and power through moving joints. This project is motivated by a previous work where an array of surface-mount momentary contact switches on a flexible circuit acted as an all-digital shape sensor compatible with the power resources of energy harvesting systems. Without a rigid segment, the smallest commercially-available surface-mount switches would detach from the flexible circuit after several bending cycles, sometimes violently. This report describes a low-cost, conductive fiber based method to integrate electromechanical switches into flexible circuits and other soft, bendable materials. Because the switches are digital (on/off), they differ from commercially-available continuous-valued bend/flex sensors. No amplification or analog-to-digital conversion is needed to read the signal, but the tradeoff is that the digital switches only give a threshold curvature value. Boundary conditions on the edges of the flexible circuit are key to setting the threshold curvature value for switching. This presentation will discuss threshold-setting, size scaling of the design, automation for inserting a digital switch into the flexible circuit fabrication process, and methods for reconstructing a shape from an array of digital switch states.

  5. Interface Board Connector

    DTIC Science & Technology

    2011-09-20

    circuit board components are generally soldered. Typically, a printed circuit board is mechanically supported by a dielectric base plate . The printed...transmission line on balun board 1. [0032] Element seat plates 12 of connectors 10 are supported by dielectric 14 and prior art partition...1. As noted previously with respect to FIG. 2, the configuration of plate 12 depends on the architecture of the interface board . For illustrative

  6. PCB breakdown by anaerobic microorganisms

    SciTech Connect

    Not Available

    1989-03-01

    Recently, altered PCB cogener distribution patterns observed in anaerobic sediment samples from the upper Hudson River are being attributed to biologically mediated reductive dechlorination. The authors report their successful demonstration of biologically mediated reductive dechlorination of an Aroclor mixture. In their investigation, they assessed the ability of microorganisms from PCB-contaminated Hudson River sediments (60-562 ppm PCBs) to dechlorinate Aroclor 1242 under anaerobic conditions by eluting microorganisms from the PCB- contaminated sediments and transferring them to a slurry of reduced anaerobic mineral medium and PCB-free sediments in tightly stoppered bottles. They observed dechlorination to be the most rapid at the highest PCB concentration tried by them.

  7. Recycling of lead solder dross, Generated from PCB manufacturing

    NASA Astrophysics Data System (ADS)

    Lucheva, Biserka; Tsonev, Tsonio; Iliev, Peter

    2011-08-01

    The main purpose of this work is to analyze lead solder dross, a waste product from manufacturing of printed circuit boards by wave soldering, and to develop an effective and environmentally sound technology for its recycling. A methodology for determination of the content and chemical composition of the metal and oxide phases of the dross is developed. Two methods for recycling of lead solder dross were examined—carbothermal reduction and recycling using boron-containing substances. The influence of various factors on the metal yield was studied and the optimal parameters of the recycling process are defined. The comparison between them under the same parameters-temperature and retention time, showed that recycling of dross with a mixture of borax and boric acid in a 1:2 ratio provides higher metal yield (93%). The recycling of this hazardous waste under developed technology gets glassy slag and solder, which after correction of the chemical composition can be used again for production of PCB.

  8. Evaluating the Effects of Aging on Electronic Instrument and Control Circuit Boards and Components in Nuclear Power Plants

    SciTech Connect

    G. William Hannaman; C. Dan Wilkinson

    2005-05-15

    The report describes potentially useful techniques for monitoring the aging of I&C boards. The techniques have been grouped into: periodic testing, reliability modeling, resistance measures, signal comparison, eternal measures, and internal measures, each representing distinct theoretical approaches to detection and evaluation.

  9. Simulation of high SNR photodetector with L-C coupling and transimpedance amplifier circuit and its verification

    NASA Astrophysics Data System (ADS)

    Wang, Shaofeng; Xiang, Xiao; Zhou, Conghua; Zhai, Yiwei; Quan, Runai; Wang, Mengmeng; Hou, Feiyan; Zhang, Shougang; Dong, Ruifang; Liu, Tao

    2017-01-01

    In this paper, a model for simulating the optical response and noise performances of photodetectors with L-C coupling and transimpedance amplification circuit is presented. To verify the simulation, two kinds of photodetectors, which are based on the same printed-circuit-board (PCB) designing and PIN photodiode but different operational amplifiers, are developed and experimentally investigated. Through the comparisons between the numerical simulation results and the experimentally obtained data, excellent agreements are achieved, which show that the model provides a highly efficient guide for the development of a high signal to noise ratio photodetector. Furthermore, the parasite capacitances on the developed PCB, which are always hardly measured but play a non-negligible influence on the photodetectors' performances, are estimated.

  10. Low-loss characteristics of a multimode polymer optical circuit at 1.3-μm wavelength on printed circuit board

    NASA Astrophysics Data System (ADS)

    Amano, Takeru; Noriki, Akihiro

    2017-02-01

    We propose an optical and electrical hybrid LSI package with high bandwidth of 2.4 Tb/s and parallel multi-mode optical links at 1.3 μm using a polymer optical waveguide and our original optical I/O module. We report a silicate based organic-inorganic hybrid polymer optical circuit fabrication including waveguide, mirror and connector on electrical LSI package substrate. We also present about the propagation loss, bending loss and coupling loss at 1.3 μm using a MMF and a Si photonics transmitter. The propagation loss of the multimode polymer waveguide is 0.3 dB/cm at 1.3 μm. The minimum bending radian and value generated additional loss is 5 mm and 0.2 dB, respectively. The coupling loss of butt-coupling and mirror coupling from the polymer optical waveguide to the MMF is 0.4 dB and 1.2 dB, respectively. In addition, we measure the optical characteristics of LSI package substrate using our Si photonics transmitter integrated with vertical polymer waveguide. Owing to adoption of multi-mode transmission, large 1-dB alignment tolerances were obtained with efficient optical coupling.

  11. Eco-friendly copper recovery process from waste printed circuit boards using Fe³⁺/Fe²⁺ redox system.

    PubMed

    Fogarasi, Szabolcs; Imre-Lucaci, Florica; Egedy, Attila; Imre-Lucaci, Árpád; Ilea, Petru

    2015-06-01

    The present study aimed at developing an original and environmentally friendly process for the recovery of copper from waste printed circuit boards (WPCBs) by chemical dissolution with Fe(3+) combined with the simultaneous electrowinning of copper and oxidant regeneration. The recovery of copper was achieved in an original set-up consisting of a three chamber electrochemical reactor (ER) connected in series with a chemical reactor (CR) equipped with a perforated rotating drum. Several experiments were performed in order to identify the optimal flow rate for the dissolution of copper in the CR and to ensure the lowest energy consumption for copper electrodeposition in the ER. The optimal hydrodynamic conditions were provided at 400 mL/min, leading to the 75% dissolution of metals and to a low specific energy consumption of 1.59 kW h/kg Cu for the electrodeposition process. In most experiments, the copper content of the obtained cathodic deposits was over 99.9%.

  12. The major components of particles emitted during recycling of waste printed circuit boards in a typical e-waste workshop of South China

    NASA Astrophysics Data System (ADS)

    Bi, Xinhui; Simoneit, Bernd R. T.; Wang, ZhenZhen; Wang, Xinming; Sheng, Guoying; Fu, Jiamo

    2010-11-01

    Electronic waste from across the world is dismantled and disposed of in China. The low-tech recycling methods have caused severe air pollution. Air particle samples from a typical workshop of South China engaged in recycling waste printed circuit boards have been analyzed with respect to chemical constituents. This is the first report on the chemical composition of particulate matter (PM) emitted in an e-waste recycling workshop of South China. The results show that the composition of PM from this recycling process was totally different from other emission sources. Organic matter comprised 46.7-51.6% of the PM. The major organic constituents were organophosphates consisting mainly of triphenyl phosphate (TPP) and its methyl substituted compounds, methyl esters of hexadecanoic and octadecanoic acids, levoglucosan and bisphenol A. TPP and bisphenol A were present at 1-5 orders of magnitude higher than in other indoor and outdoor environments throughout the world, which implies that they might be used as potential markers for e-waste recycling. The elemental carbon, inorganic elements and ions had a minor contribution to the PM (<5% each). The inorganic elements were dominated by phosphorus and followed by crustal elements and metal elements Pb, Zn, Sn, and lesser Cu, Sb, Mn, Ni, Ba and Cd. The recycling of printed circuit boards was demonstrated as an important contributor of heavy metal contamination, particularly Cd, Pb and Ni, to the local environment. These findings suggest that this recycling method represents a strong source of PM associated with pollutants to the ambient atmosphere of an e-waste recycling locale.

  13. Computer simulation of the pneumatic separator in the pneumatic-electrostatic separation system for recycling waste printed circuit boards with electronic components.

    PubMed

    Xue, Mianqiang; Xu, Zhenming

    2013-05-07

    Technologies could be integrated in different ways into automatic recycling lines for a certain kind of electronic waste according to practical requirements. In this study, a new kind of pneumatic separator with openings at the dust hooper was applied combing with electrostatic separation for recycling waste printed circuit boards. However, the flow pattern and the particles' movement behavior could not be obtained by experimental methods. To better control the separation quantity and the material size distribution, computational fluid dynamics was used to model the new pneumatic separator giving a detailed understanding of the mechanisms. Simulated results showed that the tangential velocity direction reversed with a relatively small value. Axial velocity exhibited two sharp decreases at the x axis. It is indicated that the bottom openings at the dust hopper resulted in an enormous change in the velocity profile. A new phenomenon that was named dusting was observed, which would mitigate the effect of particles with small diameter on the following electrostatic separation and avoid materials plugging caused by the waste printed circuit boards special properties effectively. The trapped materials were divided into seven grades. Experimental results showed that the mass fraction of grade 5, grade 6, and grade 7 materials were 27.54%, 15.23%, and 17.38%, respectively. Grade 1 particles' mass fraction was reduced by 80.30% compared with a traditional separator. Furthermore, the monocrystalline silicon content in silicon element in particles with a diameter of -0.091 mm was 18.9%, higher than that in the mixed materials. This study could serve as guidance for the future material flow control, automation control, waste recycling, and semiconductor storage medium destruction.

  14. A Low-cost 4 Bit, 10 Giga-samples-per-second Analog-to-digital Converter Printed Circuit Board Assembly for FPGA-based Backends

    NASA Astrophysics Data System (ADS)

    Jiang, Homin; Yu, Chen-Yu; Kubo, Derek; Chen, Ming-Tang; Guzzino, Kim

    2016-11-01

    In this study, a 4 bit, 10 giga-samples-per-second analog-to-digital converter (ADC) printed circuit board assembly (PCBA) was designed, manufactured, and characterized for digitizing radio telescopes. For this purpose, an Adsantec ANST7120A-KMA flash ADC chip was used. Together with the field-programmable gate array platform, developed by the Collaboration for Astronomy Signal Processing and Electronics Research community, the PCBA enables data acquisition with a wide bandwidth and simplifies the intermediate frequency section. In the current version, the PCBA and the chip exhibit an analog bandwidth of 10 GHz (3 dB loss) and 20 GHz, respectively, which facilitates second, third, and even fourth Nyquist sampling. The following average performance parameters were obtained from the first and second Nyquist zones of the three boards: a spurious-free dynamic range of 31.35/30.45 dB, a signal-to-noise and distortion ratio of 22.95/21.83 dB, and an effective number of bits of 3.65/3.43, respectively.

  15. Display glass for low-loss and high-density optical interconnects in electro-optical circuit boards with eight optical layers.

    PubMed

    Brusberg, Lars; Whalley, Simon; Herbst, Christian; Schröder, Henning

    2015-12-14

    Parallel optical interconnects on-board level requires low propagation loss in wavelength range between 850 and 1550 nm to be compatible with datacom and telecom optical engines. For highest integration density tight waveguide bends and a scalable number of optical layers should be manufacturable for 2D interfaces to optical fiber array connectors and photonic assembly I/O's. We developed a glass waveguide panel process for double-sided processing of commercial available display glass by applying a two-step thermal ion-exchange process for low-loss multi-mode graded-index waveguides. Multiple glass waveguide panels can be embedded between electrical layers. The generic concept enables fabrication of high-density integration (HDI) electro-optical circuit boards (EOCB) with high number of optical and electrical layers. Waveguides with high NA of 0.3 for low bend losses could be achieved in glass with propagation loss of 0.05 dB/cm for all key wavelengths. Four of those glass waveguide panels were embedded in an EOCB demonstrator with size of 280 x 233 mm² providing eight optical layers with 96 channels in an area of 2.8 x 1.5 mm². To the best of our knowledge it's the highest number of layers that has ever been demonstrated for an EOCB.

  16. ENANTIOSELECTIVITY IN THE BIODEGRADATION OF PCB ATROPISOMERS

    EPA Science Inventory

    Microcosms inoculated with sediment from two locations in a contaminated reservoir, Lake Hartwell, SC, USA, degraded certain PCB atropisomers enantioselectively while other atropisomers were degraded in racemic proportions. The microcosms were spiked with either 234-236 PCB (PCB...

  17. CADAT Printed-Wiring-Board Designer

    NASA Technical Reports Server (NTRS)

    Brinkerhoff, C. D.

    1982-01-01

    CADAT printed-wiring-board system (PWB) designs printed-circuit and hybrid-circuit boards. It is comprised of four programs: preprocessor, placement program, organizer program, and the router. Component placement and interconnection paths are optimized.

  18. Slit Effect of Common Ground Patterns in Affecting Cross-Talk Noise between Two Parallel Signal Traces on Printed Circuit Boards

    NASA Astrophysics Data System (ADS)

    Maeno, Tsuyoshi; Sakurai, Yukihiko; Unou, Takanori; Ichikawa, Kouji; Fujiwara, Osamu

    It is well-known that electromagnetic (EM) disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring-harnesses from vehicle-mounted printed circuit boards (PCBs) with common ground patterns with slits. To evaluate the noise current outflows from the PCBs of this kind, we previously measured noise current outflows from four types of simple three-layer PCBs having two perpendicular signal traces and different ground patterns with/without slits, and showed that slits on a ground pattern allow conducted noise currents to flow out from PCBs, while the levels for the symmetric slits ground type are smaller compared to the case for two asymmetric slits ground types. In the present study, to further investigate the above finding, we fabricated six types of simple two-layer PCBs having two parallel signal traces and different ground patterns with/without slits, and measured the cross-talk noise between the traces. As a result, we found that the ground patterns with the slits perpendicular to the traces increase the cross-talk noise levels, which are larger by 19-42 dB than those for the ground pattern with no slits, while the ground patterns with the slits in parallel with the traces can suppress the noise levels, which are slightly smaller by 2.5-4.5 dB compared to the case for the no-slit ground pattern. These results were confirmed by the FDTD simulation, and were also qualitatively explained from an equivalent bridge circuit model we previously proposed.

  19. Study on the influence of various factors in the hydrometallurgical processing of waste printed circuit boards for copper and gold recovery.

    PubMed

    Birloaga, Ionela; De Michelis, Ida; Ferella, Francesco; Buzatu, Mihai; Vegliò, Francesco

    2013-04-01

    The present lab-scale experimental study presents the process of leaching waste printed circuit boards (WPCBs) in order to recover gold by thioureation. Preliminary tests have shown that copper adversely affects gold extraction; therefore an oxidative leaching pre-treatment was performed in order to remove base metals. The effects of sulfuric acid concentration, hydrogen peroxide volume and temperature on the metal extraction yield were studied by analysis of variance (ANOVA). The highest copper extraction yields were 76.12% for sample A and 18.29% for sample D, after leaching with 2M H2SO4, 20 ml of 30% H2O2 at 30°C for 3h. In order to improve Cu removal, a second leaching was performed only on sample A, resulting in a Cu extraction yield of 90%. Other experiments have shown the negative effect of the stirring rate on copper dissolution. The conditions used for the process of gold extraction by thiourea were: 20 g/L thiourea, 6g/L ferric ion, 10 g/L sulfuric acid, 600 rpm stirring rate. To study the influence of temperature and particle size, this process was tested on pins manually removed from computer central processing units (CPUs) and on waste CPU for 3½ h. A gold extraction yield of 69% was obtained after 75% of Cu was removed by a double oxidative leaching treatment of WPCBs with particle sizes smaller than 2 mm.

  20. The effect of additives on migration and transformation of gaseous pollutants in the vacuum pyrolysis process of waste printed circuit boards.

    PubMed

    Xie, Yibiao; Sun, Shuiyu; Liu, Jingyong; Lin, Weixiong; Chen, Nanwei; Ye, Maoyou

    2017-02-01

    The effect of six additives (CaCO3, HZSM-5, CaO, Al2O3, FeOOH and Ca(OH)2) on the generation, migration, transformation and escaping behaviours of typical gaseous pollutants in the pyrolysis process were studied by vacuum pyrolysis experiments on epoxy resin powder from waste printed circuit boards with tube furnace. The results show that the additives Al2O3, CaO, Ca(OH) 2 and FeOOH could reduce the yield of the gas phase. The removal rates of pollutants, such as benzene, toluene, ethyl benzene, phenol, p-xylene, HBr, NO2 and SO2 in the gaseous products, has changed variously with the increasing percentage of the above additives. Judging from the control of gas-phase pollutant discharge, the calcium-base additives are superior to the others. Ca(OH)2 has the best inhibition effect among them. The increase of the pyrolysis temperature and vacuum degree enhanced the volatility of organic pollutants and weakened the Ca(OH)2 inhibition effect on organic pollutants, while it improved the removal rate of SO2. Under the condition of 500 °C pyrolysis temperature and 0.09 MPa vacuum degree, when the additive proportion of Ca(OH)2 was one-fifth, the average removal rate of pollutants in gas phase is up to 66.4%.

  1. Eco-friendly copper recovery process from waste printed circuit boards using Fe{sup 3+}/Fe{sup 2+} redox system

    SciTech Connect

    Fogarasi, Szabolcs; Imre-Lucaci, Florica; Egedy, Attila; Imre-Lucaci, Árpád; Ilea, Petru

    2015-06-15

    Highlights: • We developed an ecofriendly mediated electrochemical process for copper recovery. • The recovery of copper was achieved without mechanical pretreatment of the samples. • We identified the optimal flow rate for the leaching and electrowinning of copper. • The copper content of the obtained cathodic deposits was over 99.9%. - Abstract: The present study aimed at developing an original and environmentally friendly process for the recovery of copper from waste printed circuit boards (WPCBs) by chemical dissolution with Fe{sup 3+} combined with the simultaneous electrowinning of copper and oxidant regeneration. The recovery of copper was achieved in an original set-up consisting of a three chamber electrochemical reactor (ER) connected in series with a chemical reactor (CR) equipped with a perforated rotating drum. Several experiments were performed in order to identify the optimal flow rate for the dissolution of copper in the CR and to ensure the lowest energy consumption for copper electrodeposition in the ER. The optimal hydrodynamic conditions were provided at 400 mL/min, leading to the 75% dissolution of metals and to a low specific energy consumption of 1.59 kW h/kg Cu for the electrodeposition process. In most experiments, the copper content of the obtained cathodic deposits was over 99.9%.

  2. Triboelectric separation technology for removing inorganics from non-metallic fraction of waste printed circuit boards: Influence of size fraction and process optimization.

    PubMed

    Zhang, Guangwen; Wang, Haifeng; He, Yaqun; Yang, Xing; Peng, Zhen; Zhang, Tao; Wang, Shuai

    2017-02-01

    Removing inorganics from non-metallic fraction (NMF) of waste printed circuit boards (WPCBs) is an effective mean to improve its usability. The effect of size fraction on the triboelectric separation of NMF of WPCBs was investigated in a lab triboelectric separation system and the separation process was optimized in this paper. The elements distribution in raw NMF collected from typical WPCBs recycling plant and each size fraction obtained by sieving were analyzed by X-ray fluorescence (XRF). The results show that the main inorganic elements in NMF are P, Ba, Mn, Sb, Ti, Pb, Zn, Sn, Mg, Fe, Ca, Cu, Al and Si. The inorganic content of each size fraction increased with the size decreasing. The metal elements are mainly distributed in -0.2mm size fraction, and concentrated in middle product of triboelectric separation. The loss on ignition (LOI) of positive product and negative product is higher than that of the middle product for the -0.355mm size fraction, while the LOI presents gradually increasing trend from negative to positive plate for the +0.355mm size fraction. Based on the separation results and mineralogical characterizations of each size fraction of NMF, the pretreatment process including several mineral processing operations was added before triboelectric separation and better separation result was obtained. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. A new technology for separation and recovery of materials from waste printed circuit boards by dissolving bromine epoxy resins using ionic liquid.

    PubMed

    Zhu, P; Chen, Y; Wang, L Y; Qian, G Y; Zhou, M; Zhou, J

    2012-11-15

    Recovery of valuable materials from waste printed circuit boards (WPCBs) is quite difficult because WPCBs is a heterogeneous mixture of polymer materials, glass fibers, and metals. In this study, WPCBs was treated using ionic liquid (1-ethyl-3-methylimizadolium tetrafluoroborate [EMIM+][BF4-]). Experimental results showed that the separation of the solders went to completion, and electronic components (ECs) were removed in WPCBs when [EMIM+][BF4-] solution containing WPCBs was heated to 240 °C. Meanwhile, metallographic observations verified that the WPCBs had an initial delamination. When the temperature increased to 260 °C, the separation of the WPCBs went to completion, and coppers and glass fibers were obtained. The used [EMIM+][BF4-] was treated by water to generate a solid-liquid suspension, which was separated completely to obtain solid residues by filtration. Thermal analyses combined with infrared ray spectra (IR) observed that the solid residues were bromine epoxy resins. NMR (nuclear magnetic resonance) showed that hydrogen bond played an important role for [EMIM+][BF4-] dissolving bromine epoxy resins. This clean and non-polluting technology offers a new way to recycle valuable materials from WPCBs and prevent environmental pollution from WPCBs effectively.

  4. Recycling of waste printed circuit boards with simultaneous enrichment of special metals by using alkaline melts: A green and strategically advantageous solution.

    PubMed

    Stuhlpfarrer, Philipp; Luidold, Stefan; Antrekowitsch, Helmut

    2016-04-15

    The increasing consumption of electric and electronic equipment has led to a rise in toxic waste. To recover the metal fraction, a separation of the organic components is necessary because harmful substances such as chlorine, fluorine and bromine cause ecological damage, for example in the form of dioxins and furans at temperature above 400°C. Hence, an alternative, environmentally friendly approach was investigated exploiting that a mixture of caustic soda and potassium hydroxide in eutectic composition melts below 200°C, enabling a fast cracking of the long hydrocarbon chains. The trials demonstrate the removal of organic compounds without a loss of copper and precious metals, as well as a suppressed formation of hazardous off-gases. In order to avoid an input of alkaline elements into the furnace and ensuing problems with refractory materials, a washing step generates a sodium and potassium hydroxide solution, in which special metals like indium, gallium and germanium are enriched. Their concentrations facilitate the recovery of these elements, because otherwise they become lost in the typical recycling processes. The aim of this work was to find an environmental solution for the separation of plastics and metals as well as a strategically important answer for the recycling of printed circuit boards and mobile phones. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Halogenated organic pollutants in particulate matters emitted during recycling of waste printed circuit boards in a typical e-waste workshop of Southern China.

    PubMed

    Ren, Zhaofang; Xiao, Xiao; Chen, Deyi; Bi, Xinhui; Huang, Bo; Liu, Ming; Hu, Jianfang; Peng, Ping'an; Sheng, Guoying; Fu, Jiamo

    2014-01-01

    Air particle samples collected from a typical workshop of Southern China engaged in recycling waste printed circuit boards were analyzed for PBDEs, PCDD/Fs, and PBDD/Fs. The concentrations and profiles of these compounds were presented. Concentrations ofPPBDEs,PPCDD/Fs andPPBDD/Fs in this workshop were 948 ng m⁻³, 317 pg m⁻³ (14.5 pg WHO-TEQ m⁻³) and 481 pg m⁻³ (91.3 pg I-TEQ m⁻³), respectively. BDEs-47, -99, and -209 were the dominant PBDE congeners, and the relatively high levels of octaand nona-BDEs might be generated from the degradation of BDE-209. The levels of 2,3,7,8-PCDD/Fs and 2,3,7,8-PBDD/Fs were much higher than those in the atmospheric environment, and concentrations of PBDD/Fs were higher than those of PCDD/Fs. These findings suggest that the primitive recycling method represents a strong source of halogenated organic pollutants to the ambient atmosphere of an e-waste recycling locale.

  6. Co-recycling of acrylonitrile-butadiene-styrene waste plastic and nonmetal particles from waste printed circuit boards to manufacture reproduction composites.

    PubMed

    Sun, Zhixing; Shen, Zhigang; Zhang, Xiaojing; Ma, Shulin

    2015-01-01

    This study investigated the feasibility of using acrylonitrile-butadiene-styrene (ABS) waste plastic and nonmetal particles from waste printed circuit boards (WPCB) to manufacture reproduction composites (RC), with the aim of co-recycling these two waste resources. The composites were prepared in a twin-crew extruder and investigated by means of mechanical testing, in situ flexural observation, thermogravimatric analysis, and dimensional stability evaluation. The results showed that the presence of nonmetal particles significantly improved the mechanical properties and the physical performance of the RC. A loading of 30 wt% nonmetal particles could achieve a flexural strength of 72.6 MPa, a flexural modulus of 3.57 GPa, and an impact strength of 15.5 kJ/m2. Moreover, it was found that the application of maleic anhydride-grafted ABS as compatilizer could effectively promote the interfacial adhesion between the ABS plastic and the nonmetal particles. This research provides a novel method to reuse waste ABS and WPCB nonmetals for manufacturing high value-added product, which represents a promising way for waste recycling and resolving the environmental problem.

  7. Study of the physicochemical effects on the separation of the non-metallic fraction from printed circuit boards by inverse flotation.

    PubMed

    Flores-Campos, R; Estrada-Ruiz, R H; Velarde-Sánchez, E J

    2017-09-06

    Recycling printed circuit boards using green technology is increasingly important due to the metals these contain and the environmental care that must be taken when separating the different materials. Inverse flotation is a process that can be considered a Green Technology, which separates metallic from non-metallic fractions. The degree of separation depends on how much material is adhered to air bubbles. The contact angle measurement allows to determine, in an easy way, whether the flotation process will occur or not and thus establish a material as hydrophobic or not. With the material directly obtained from the milling process, it was found that the contact angle of the non-metallic fraction-liquid-air system increases as temperature increases. In the same way, the increments in concentration of frother in the liquid increase the contact angle of the non-metallic fraction-liquid-air system. 10ppm of Methyl Isobutyl Carbinol provides the highest contact angle as well as the highest material charging in the bubble. Copyright © 2017. Published by Elsevier Ltd.

  8. Circuit Connectors

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The U-shaped wire devices in the upper photo are Digi-Klipsm; aids to compact packaging of electrical and electronic devices. They serve as connectors linking the circuitry of one circuit board with another in multi-board systems. Digi-Klips were originally developed for Goddard Space Flight Center to meet a need for lightweight, reliable connectors to replace hand-wired connections formerly used in spacecraft. They are made of beryllium copper wire, noted for its excellent conductivity and its spring-like properties, which assure solid electrical contact over a long period of time.

  9. Rapid micro-optical prototyping technology for fabricating optical interconnection modules at the MCM and PCB level

    NASA Astrophysics Data System (ADS)

    Debaes, C.; Vervaeke, M.; Van Erps, J.; Desmet, L.; Ottevaere, H.; Gomez, V.; Vynck, P.; Van Overmeire, S.; Ishii, Y.; Hermanne, A.; Thienpont, H.

    2006-10-01

    One of the remaining challenges to solve the interconnection bottlenecks at the Printed Circuit Board (PCB) and Multi-Chip-Module (MCM) level, is to adequately replace the galvanic interconnects with high-performance, low-cost, compact and reliable micro-photonic alternatives. At our labs of the Vrije Universiteit Brussel we are therefore optimizing and deploying a rapid micro-optical prototyping technology for micro-optical interconnect modules, which we call Deep Proton Writing (DPW). An advantage of the DPW process is that it can create steep micro-optical surfaces, micro-holes, micro-lenses and alignment features in one irradation step. Hence, relative accuracies are very well controlled. In this report, we will address more specifically the following components, made each with the DPW technology: 1) out-of-plane couplers for optical wave-guides embedded in PCB, 2) peripheral fiber ribbons and two dimensional single- and multimode fiber connectors for high-speed parallel optical connections, and 3) intra-MCM level optical interconnections via free-space optical modules. We will give special attention to the optical tolerancing and the opto-mechanical integration of components in their packages. We use both a sensitivity analysis to misalignment errors and Monte-Carlo simulations. It is our aim to investigate the whole component integration chain from the optoelectronic device packaging to the micro-opto-mechanical assembly of the interconnect module.

  10. Disposal requirements for PCB waste

    SciTech Connect

    1994-12-01

    Polychlorinated biphenyls (PCBs) are a class of organic chemicals that had become widely used in industrial applications due to their practical physical and chemical properties. Historical uses of PCBs include dielectric fluids (used in utility transformers, capacitors, etc.), hydraulic fluids, and other applications requiring stable, fire-retardant materials. Due to findings that PCBs may cause adverse health effects and due to their persistence and accumulation in the environment, the Toxic Substances Control Act (TSCA), enacted on october 11, 1976, banned the manufacture of PCBs after 1978 [Section 6(e)]. The first PCB regulations, promulgated at 40 CFR Part 761, were finalized on February 17, 1978. These PCB regulations include requirements specifying disposal methods and marking (labeling) procedures, and controlling PCB use. To assist the Department of Energy (DOE) in its efforts to comply with the TSCA statute and implementing regulations, the Office of Environmental Guidance has prepared the document ``Guidance on the Management of Polychlorinated Biphenyls (PCBs).`` That document explains the requirements specified in the statute and regulations for managing PCBs including PCB use, storage, transport, and disposal. PCB materials that are no longer in use and have been declared a waste must be disposed of according to the requirements found at 40 CFR 761.60. These requirements establish disposal options for a multitude of PCB materials including soil and debris, liquid PCBs, sludges and slurries, containers, transformers, capacitors, hydraulic machines, and other electrical equipment. This Information Brief supplements the PCB guidance document by responding to common questions concerning disposal requirements for PCBs. It is one of a series of Information Briefs pertinent to PCB management issues.

  11. Evaluation of Cleanliness Test Methods for Spacecraft PCB Assemblies

    NASA Astrophysics Data System (ADS)

    Tegehall, P.-E.; Dunn, B. D.

    2006-10-01

    Ionic contamination on printed-circuit-board assemblies may cause current leakage and short-circuits. The present cleanliness requirement in ECSS-Q-70-08, "The manual soldering of high-reliability electrical connections", is that the ionic contamination shall be less than 1.56 fl-glcm2 NaCI equivalents. The relevance of the method used for measurement of the ionic contamination level, resistivity of solvent extract, has been questioned. Alternative methods are ion chromatography and measurement of surface insulation resistance, but these methods also have their drawbacks. These methods are first described and their advantages and drawbacks are discussed. This is followed by an experimental evaluation of the three methods. This was done by soldering test vehicles at four manufacturers of space electronics using their ordinary processes for soldering and cleaning printed board assemblies. The experimental evaluation showed that the ionic contamination added by the four assemblers was very small and well below the acceptance criterion in ECSS-Q-70-80. Ion-chromatography analysis showed that most of the ionic contamination on the cleaned assembled boards originated from the hot-oil fusing of the printed circuit boards. Also, the surface insulation resistance was higher on the assembled boards compared to the bare printed circuit boards. Since strongly activated fluxes are normally used when printed circuit boards are hot-oil fused, it is essential that they are thoroughly cleaned in order to achieve low contamination levels on the final printed-board assemblies.

  12. Pulse Responses of a Two-layered Printed Circuit with an Improved Line-Pad Connected Structure

    NASA Astrophysics Data System (ADS)

    Kobayashi, Daisuke; Furukawa, Shinichi; Hinata, Takashi

    The peak value of transmitted pulse in printed circuit boards (PCB) is important for a pulse peak detection devices. When an input line and an output line are connected to each pad with the direction of right angle, the propagating pulses with the narrow time duration separate into some parts and decrease the peak value of pulse response. This paper presents an improved line-pad connected structure. The microstrip line is in contact with a pad from outside by considering the pulse propagation time passing through the via structure. We obtained the large peak value of the pulse response for which the time duration is larger than 0.2ps.

  13. Modeling and characteristic of the SMT Board Plug connector in high speed optical communication system

    NASA Astrophysics Data System (ADS)

    Wu, Haoran; Dong, Zhenzhen; Wang, Tanglin; Zhao, Heng; Feng, Junbo; Cui, Naidi; Teng, Jie; Guo, Jin

    2015-04-01

    Modeling and characteristic of the SMT Board Plug connector, which is used to connect micro optical transceiver to the main board, are proposed and analyzed in this paper. When the high speed signal transfers from the PCB of transceiver to main board through SMT Board Plug connector, the structure and material discontinuity of the connector causes insertion losses and impedance mismatches. This makes the performance of high speed digital system exacerbated. So it is essential to analyze the signal transfer characteristics of the connector and find out what factors affected the signal quality at the design stage of the digital system. To solve this problem, Ansoft's High Frequency Structure Simulator (HFSS), based on the finite element method, was employed to build accurate 3D models, analyze the effects of various structure parameters, and obtain the full-wave characteristics of the SMT Board Plug connectors in this paper. Then an equivalent circuit model was developed. The circuit parameters were extracted precisely in the frequency range of interests by using the curve fitting method in ADS software, and the result was in good agreement with HFSS simulations up to 8GHz with different structure parameters. At last, the measurement results of S-parameter and eye diagram were given and the S-parameters showed good coincidence between the measurement and HFSS simulation up to 4GHz.

  14. Leaching of Au, Ag, and Pd from waste printed circuit boards of mobile phone by iodide lixiviant after supercritical water pre-treatment.

    PubMed

    Xiu, Fu-Rong; Qi, Yingying; Zhang, Fu-Shen

    2015-07-01

    Precious metals are the most attractive resources in waste printed circuit boards (PCBs) of mobile phones. In this work, an alternative process for recovering Au, Ag, and Pd from waste PCBs of mobile phones by supercritical water oxidation (SCWO) pre-treatment combined with iodine-iodide leaching process was developed. In the process, the waste PCBs of mobile phones were pre-treated in supercritical water, then a diluted hydrochloric acid leaching (HL) process was used to recovery the Cu, whose leaching efficiency was approximately 100%, finally the resulting residue was subjected to the iodine-iodide leaching process for recovering the Au, Ag, and Pd. Experimental results indicated that SCWO pre-treatment temperature, time, and pressure had significant influence on the Au, Ag, and Pd leaching from (SCWO+HL)-treated waste PCBs. The optimal SCWO pre-treatment conditions were 420°C and 60min for Au and Pd, and 410°C and 30min for Ag. The optimum dissolution parameters for Au, Pd, and Ag in (SCWO+HL)-treated PCBs with iodine-iodide system were leaching time of 120min (90min for Ag), iodine/iodide mole ratio of 1:5 (1:6 for Ag), solid-to-liquid ratio (S/L) of 1:10g/mL (1:8g/mL for Ag), and pH of 9, respectively. It is believed that the process developed in this study is environment friendly for the recovery of Au, Ag, and Pd from waste PCBs of mobile phones by SCWO pre-treatment combined with iodine-iodide leaching process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Graded-index core polymer optical waveguide circuit fabricated using a microdispenser for high-density on-board optical interconnects

    NASA Astrophysics Data System (ADS)

    Soma, Kazutomo; Ishigure, Takaaki

    2013-02-01

    We introduce a simple photo-mask-free fabrication method of multimode polymer optical waveguides (PPOWs): "the Mosquito method" that utilizes a micro-dispenser. In the Mosquito method, a viscous monomer for cores is directly dispensed from a thin needle into a cladding monomer that is coated on a substrate. Because of the monomer diffusion, graded-index (GI) circular core is formed. By adjusting several parameters to control the core shape and diameter, 15-cm long, 40-μm core diameter, with 125-μm pitch GI-circular core PPOWs (12 channels) are successfully fabricated by the Mosquito method. We experimentally demonstrate superior optical properties of the GI- circular core polymer waveguides: connection loss with GI multimode fibers, inter-channel crosstalk, etc. to SI-square core polymer waveguides composed of the same silicone polymer materials. Furthermore, we fabricate GI-core PPOW circuits in which perpendicularly curved waveguides are involved by applying the Mosquito method. The curved PPOWs with a 250-μm pitch are obtained successfully and the curve-radius is varied from 3 mm to 20 mm by adjusting the scanning program of the needle. The insertion loss of the curved waveguides is measured for evaluating the bending losses. The waveguide with lager curve-radius shows lower insertion loss, namely low bending loss. Additionally, it is experimentally confirmed that the curved waveguides with higher numerical aperture (NA = 0.30) fabricated utilizing a different silicone resin for the cladding exhibit a bending loss as low as 0.5 dB even under 3-mm curve radius. The Mosquito-method would be a promising method for realizing highspeed and high-density on-board optical interconnects.

  16. Advanced degradation of brominated epoxy resin and simultaneous transformation of glass fiber from waste printed circuit boards by improved supercritical water oxidation processes.

    PubMed

    Liu, Kang; Zhang, Zhiyuan; Zhang, Fu-Shen

    2016-10-01

    This work investigated various supercritical water oxidation (SCWO) systems, i.e. SCWO1 (only water), SCWO2 (water+H2O2) and SCWO3 (water+H2O2/NaOH), for waste printed circuit boards (PCBs) detoxification and recycling. Response surface methodology (RSM) was applied to optimize the operating conditions of the optimal SCWO3 systems. The optimal reaction conditions for debromination were found to be the NaOH of 0.21g, the H2O2 volume of 9.04mL, the time of 39.7min, maximum debromination efficiency of 95.14%. Variance analysis indicated that the factors influencing debromination efficiency was in the sequence of NaOH>H2O2>time. Mechanism studies indicated that the dissociated ions from NaOH in supercritical water promoted the debromination of brominated epoxy resins (BERs) through an elimination reaction and nucleophilic substitution. HO2, produced by H2O2 could induce the oxidation of phenol ring to open (intermediates of BERs), which were thoroughly degraded to form hydrocarbons, CO2, H2O and NaBr. In addition, the alkali-silica reaction between OH(-) and SiO2 induced the phase transformation of glass fibers, which were simultaneously converted into anorthite and albite. Waste PCBs in H2O2/NaOH improved SCWO system were fully degraded into useful products and simultaneously transformed into functional materials. These findings are helpful for efficient recycling of waste PCBs.

  17. Assessment of noise and heavy metals (Cr, Cu, Cd, Pb) in the ambience of the production line for recycling waste printed circuit boards.

    PubMed

    Xue, Mianqiang; Yang, Yichen; Ruan, Jujun; Xu, Zhenming

    2012-01-03

    The crush-pneumatic separation-corona electrostatic separation production line provides a feasible method for industrialization of waste printed circuit boards (PCBs) recycling. To determine the potential environmental contamination in the automatic line workshop, noise and heavy metals (Cr, Cu, Cd, Pb) in the ambience of the production line have been evaluated in this paper. The mean noise level in the workshop has been reduced from 96.4 to 79.3 dB since the engineering noise control measures were employed. Noise whose frequency ranged from 500 to 1000 Hz is controlled effectively. The mass concentrations of TSP and PM(10) in the workshop are 282.6 and 202.0 μg/m(3), respectively. Pb (1.40 μg/m(3)) and Cu (1.22 μg/m(3)) are the most enriched metals in TSP samples followed by Cr (0.17 μg/m(3)) and Cd (0.028 μg/m(3)). The concentrations of Cu, Pb, Cr, and Cd in PM(10) are 0.88, 0.56, 0.12, and 0.88 μg/m(3), respectively. Among the four metals, Cr and Pb are released into the ambience of the automatic line more easily in the crush and separation process. Health risk assessment shows that noncancerous effects might be possible for Pb (HI = 1.45), and noncancerous effects are unlikely for Cr, Cu, and Cd. The carcinogenic risks for Cr and Cd are 3.29 × 10(-8) and 1.61 × 10(-9), respectively. It indicates that carcinogenic risks on workers are relatively light in the workshop. These findings suggest that this technology is advanced from the perspective of environmental protection in the waste PCBs recycling industry.

  18. Printed wiring board system programmer's manual

    NASA Technical Reports Server (NTRS)

    Brinkerhoff, C. D.

    1973-01-01

    The printed wiring board system provides automated techniques for the design of printed circuit boards and hybrid circuit boards. The system consists of four programs: (1) the preprocessor program combines user supplied data and pre-defined library data to produce the detailed circuit description data; (2) the placement program assigns circuit components to specific areas of the board in a manner that optimizes the total interconnection length of the circuit; (3) the organizer program assigns pin interconnections to specific board levels and determines the optimal order in which the router program should attempt to layout the paths connecting the pins; and (4) the router program determines the wire paths which are to be used to connect each input pin pair on the circuit board. This document is intended to serve as a programmer's reference manual for the printed wiring board system. A detailed description of the internal logic and flow of the printed wiring board programs is included.

  19. PCB cycling in marine plankton

    SciTech Connect

    Ashizawa, D.; Brownawell, B.; Fisher, N.

    1995-12-31

    Ecosystem-scale models of contaminant bioaccumulation and toxicity are often sensitive to quantification of uptake and trophic transfer at the base of aquatic food chains. Significant uncertainty remains in assessing the rates and routes of transfer of hydrophobic contaminants by phytoplankton and zooplankton. Using radio-labeled 2,2{prime},4,4{prime}-tetrachlorobiphenyl (PCB), the authors have conducted experiments to measure the transfer of PCB from seawater to phytoplankton to copepods. Uptake, equilibration, and release of PCB onto/from algal cells were found to be rapid and not appreciably affected by the algal growth phase. Initial experiments indicate that when PCB-contaminated diatoms were fed to calanoid copepods, the assimilation efficiencies in the grazers ranged from 30--50%. Ongoing experiments are investigating this process further and quantitatively comparing copepod uptake of PCB from food and from the dissolved phase. These parameters of uptake and release are essential in the development and application of contaminant bioaccumulation models for marine and aquatic food chains.

  20. Advantages and Challenges of 10-Gbps Transmission on High-Density Interconnect Boards

    NASA Astrophysics Data System (ADS)

    Yee, Chang Fei; Jambek, Asral Bahari; Al-Hadi, Azremi Abdullah

    2016-06-01

    This paper provides a brief introduction to high-density interconnect (HDI) technology and its implementation on printed circuit boards (PCBs). The advantages and challenges of implementing 10-Gbps signal transmission on high-density interconnect boards are discussed in detail. The advantages (e.g., smaller via dimension and via stub removal) and challenges (e.g., crosstalk due to smaller interpair separation) of HDI are studied by analyzing the S-parameter, time-domain reflectometry (TDR), and transmission-line eye diagrams obtained by three-dimensional electromagnetic modeling (3DEM) and two-dimensional electromagnetic modeling (2DEM) using Mentor Graphics HyperLynx and Keysight Advanced Design System (ADS) electronic computer-aided design (ECAD) software. HDI outperforms conventional PCB technology in terms of signal integrity, but proper routing topology should be applied to overcome the challenge posed by crosstalk due to the tight spacing between traces.

  1. Design and characterization of a mixed-signal PCB for digital-to-analog conversion in a modular and scalable infrared scene projector

    NASA Astrophysics Data System (ADS)

    Benedict, Jacob

    Infra-red (IR) sensors have proven instrumental in a wide variety of fields from military to industrial applications. The proliferation of IR sensors has spawned an intense push for technologies that can test and calibrate the multitudes of IR sensors. One such technology, IR scene projection (IRSP), provides an inexpensive and safe method for the testing of IR sensor devices. Previous efforts have been conducted to develop IRSPs based on super-lattice light emitting diodes (SLEDS). A single-color 512x512 SLEDs system has been developed, produced, and tested as documented in Corey Lange's Master's thesis, and a GOMAC paper by Rodney McGee [1][2]. Current efforts are being undergone to develop a two-color 512x512 SLEDs system designated (TCSA). The following thesis discusses the design and implementation of a custom printed circuit board (PCB), known as the FMC 4DAC, that contains both analog and digital signals. Utilizing two 16-bit digital-to-analog converters (DAC) the purpose of the board is to provide four analog current output channels for driving the TCSA system to a maximum frame rate of 1 kHz. In addition, the board supports a scalable TCSA system architecture. Several copies of the board can be run in parallel to achieve a range of analog channels between 4 and 32.

  2. Leaching of Au, Ag, and Pd from waste printed circuit boards of mobile phone by iodide lixiviant after supercritical water pre-treatment

    SciTech Connect

    Xiu, Fu-Rong; Qi, Yingying; Zhang, Fu-Shen

    2015-07-15

    Highlights: • We report a novel process for recovering Au, Ag, and Pd from waste PCBs. • The effect of SCWO on the leaching of Au, Ag, and Pd in waste PCBs was studied. • SCWO was highly efficient for enhancing the leaching of Au, Ag, and Pd. • The optimum leaching parameters for Au, Ag, and Pd in iodine–iodide were studied. - Abstract: Precious metals are the most attractive resources in waste printed circuit boards (PCBs) of mobile phones. In this work, an alternative process for recovering Au, Ag, and Pd from waste PCBs of mobile phones by supercritical water oxidation (SCWO) pre-treatment combined with iodine–iodide leaching process was developed. In the process, the waste PCBs of mobile phones were pre-treated in supercritical water, then a diluted hydrochloric acid leaching (HL) process was used to recovery the Cu, whose leaching efficiency was approximately 100%, finally the resulting residue was subjected to the iodine–iodide leaching process for recovering the Au, Ag, and Pd. Experimental results indicated that SCWO pre-treatment temperature, time, and pressure had significant influence on the Au, Ag, and Pd leaching from (SCWO + HL)-treated waste PCBs. The optimal SCWO pre-treatment conditions were 420 °C and 60 min for Au and Pd, and 410 °C and 30 min for Ag. The optimum dissolution parameters for Au, Pd, and Ag in (SCWO + HL)-treated PCBs with iodine–iodide system were leaching time of 120 min (90 min for Ag), iodine/iodide mole ratio of 1:5 (1:6 for Ag), solid-to-liquid ratio (S/L) of 1:10 g/mL (1:8 g/mL for Ag), and pH of 9, respectively. It is believed that the process developed in this study is environment friendly for the recovery of Au, Ag, and Pd from waste PCBs of mobile phones by SCWO pre-treatment combined with iodine–iodide leaching process.

  3. Packaging Of Control Circuits In A Robot Arm

    NASA Technical Reports Server (NTRS)

    Kast, William

    1994-01-01

    Packaging system houses and connects control circuitry mounted on circuit boards within shoulder, upper section, and lower section of seven-degree-of-freedom robot arm. Has modular design that incorporates surface-mount technology, multilayer circuit boards, large-scale integrated circuits, and multi-layer flat cables between sections for compactness. Three sections of robot arm contain circuit modules in form of stardardized circuit boards. Each module contains two printed-circuit cards, one of each face.

  4. Packaging Of Control Circuits In A Robot Arm

    NASA Technical Reports Server (NTRS)

    Kast, William

    1994-01-01

    Packaging system houses and connects control circuitry mounted on circuit boards within shoulder, upper section, and lower section of seven-degree-of-freedom robot arm. Has modular design that incorporates surface-mount technology, multilayer circuit boards, large-scale integrated circuits, and multi-layer flat cables between sections for compactness. Three sections of robot arm contain circuit modules in form of stardardized circuit boards. Each module contains two printed-circuit cards, one of each face.

  5. Burial, incineration solve Alaskan PCB contamination

    SciTech Connect

    Ives, J.A. ); Young, D.T. )

    1989-10-01

    Polychlorinated biphenyl (PCB) remediation at Alaska's Swanson River has excavated more than 80,000 tons of PCB-contaminated soil and isolated it in bermed and lined stock-piles. In addition, incineration of other PCB-contaminated materials has been carried out safely. This article on the site reviews its history and part of its remediation approaches.

  6. Polychlorinated Biphenyls (PCB) Residue Effects Database

    EPA Pesticide Factsheets

    The PCB Residue Effects (PCBRes) Database was developed to assist scientists and risk assessors in correlating PCB and dioxin-like compound residues with toxic effects. The purpose is to develop PCB critical residue values for fish, mammals and birds, especially as these relate to aquatic and aquatic-dependent species.

  7. Low-cost plastic micro-optics for board level optical interconnections

    NASA Astrophysics Data System (ADS)

    Debaes, C.; Vervaeke, M.; Volckaerts, B.; Van Erps, J.; Desmet, L.; Ottevaere, H.; Vynck, P.; Gomez, V.; Hermanne, A.; Thienpont, H.

    2006-02-01

    One of the grand challenges in solving the interconnection bottlenecks at the Printed Circuit Board (PCB) and Multi-Chip-Module (MCM) level, is to adequately replace the PCB and intra-MCM galvanic interconnects with high-performance, low-cost, compact and reliable micro-photonic alternatives. In our labs at the Vrije Universiteit Brussel we are therefore focusing on the continuous development of a rapid prototyping technology for micro-optical interconnect modules, which we call Deep Proton Writing (DPW).The special feature of this prototyping technology is that it is compatible with commercial low-cost mass replication techniques such as micro injection moulding and hot embossing. We will address more specifically in this paper the following components: 1) out-of-plane couplers for optical wave-guides embedded in PCB, 2) peripheral fiber ribbons and two dimensional single- and multimode fiber connectors for high-speed parallel optical connections, and 3) intra-MCM level optical interconnections via free-space optical modules. We furthermore give special attention to the optical tolerancing and the opto-mechanical integration of the components. We use both a sensitivity analysis to misalignment errors and Monte Carlo simulations. It is our aim to investigate the whole component integration chain from the optoelectronic device to the micro-opto-mechanical components constituting the interconnect module.

  8. A compact picosecond pulsed laser source using a fully integrated CMOS driver circuit

    NASA Astrophysics Data System (ADS)

    He, Yuting; Li, Yuhua; Yadid-Pecht, Orly

    2016-03-01

    Picosecond pulsed laser source have applications in areas such as optical communications, biomedical imaging and supercontinuum generation. Direct modulation of a laser diode with ultrashort current pulses offers a compact and efficient approach to generate picosecond laser pulses. A fully integrated complementary metaloxide- semiconductor (CMOS) driver circuit is designed and applied to operate a 4 GHz distributed feedback laser (DFB). The CMOS driver circuit combines sub-circuits including a voltage-controlled ring oscillator, a voltagecontrolled delay line, an exclusive-or (XOR) circuit and a current source circuit. Ultrashort current pulses are generated by the XOR circuit when the delayed square wave is XOR'ed with the original square wave from the on-chip oscillator. Circuit post-layout simulation shows that output current pulses injected into an equivalent circuit load of the laser have a pulse full width at half maximum (FWHM) of 200 ps, a peak current of 80 mA and a repetition rate of 5.8 MHz. This driver circuit is designed in a 0.13 μm CMOS process and taped out on a 0.3 mm2 chip area. This CMOS chip is packaged and interconnected with the laser diode on a printed circuit board (PCB). The optical output waveform from the laser source is captured by a 5 GHz bandwidth photodiode and an 8 GHz bandwidth oscilloscope. Measured results show that the proposed laser source can output light pulses with a pulse FWHM of 151 ps, a peak power of 6.4 mW (55 mA laser peak forward current) and a repetition rate of 5.3 MHz.

  9. Study and Evaluation of a PCB-MEMS Liquid Microflow Sensor

    PubMed Central

    Petropoulos, Anastasios; Kaltsas, Grigoris

    2010-01-01

    This paper presents the evaluation of a miniature liquid microflow sensor, directly integrated on a PCB. The sensor operation is based on the convective heat transfer principle. The heating and sensing elements are thin Pt resistors which are in direct electrical contact with the external copper tracks of the printed circuit board. Due to the low thermal conductivity of the substrate material, a high degree of thermal isolation is obtained which improves the operating characteristics of the device. The sensor is able to operate under both the hot-wire and the calorimetric principle. In order to fully exploit the temperature distribution in the flowing liquid, multiple sensing elements are positioned in various distances from the heater. A special housing was developed which allowed implementation of the sensor into tubes of various cross sectional areas. The sensor sensitivity and measurement range as a function of the sensing element distance were quantified. A minimum resolution of 3 μL/min and a measurement flow range up to 500 μL/min were achieved. PMID:22163392

  10. Maskless fabrication of a microfluidic device with interdigitated electrodes on PCB using laser ablation

    NASA Astrophysics Data System (ADS)

    Contreras-Saenz, Michael; Hassard, Christian; Vargas-Chacon, Rafael; Gordillo, Jose Luis; Camacho-Leon, Sergio

    2016-03-01

    This paper reports the maskless fabrication of a microfluidic device with interdigitated electrodes (IDE) based on the technology of MicroElectroMechanical Systems on Printed Circuit Board (PCB-MEMS) and laser ablation. The device has flame retardant (FR)-4 resin as substrate, cooper (Cu) as active material and SU-8 polymer as structural material. By adjusting the laser parameters, Cu IDEs and SU-8 microchannels were successfully patterned onto the FR-4 substrate. The respective width, gap and overlap of the IDEs were 50 μm, 25 μm and 500 μm. The respective width, depth and length of the microchannels were 210 μm, 24.6 μm and 6.3 mm. The resolution and repeatability achieved in this approach, along with the low cost of the involved materials and techniques, enable an affordable micromachining platform with rapid fabrication-test cycle to develop active multiphysic microdevices with several applications in the fields of biosensing, cell culture, drug delivery, transport and sorting of molecules, among others.

  11. Environmental risk assessment of CRT and PCB workshops in a mobile e-waste recycling plant.

    PubMed

    Song, Qingbin; Zeng, Xianlai; Li, Jinhui; Duan, Huabo; Yuan, Wenyi

    2015-08-01

    The mobile e-waste recycling equipment was chosen as the object of this study, including manual dismantling, mechanical separation of cathode ray tubes (CRTs), and printed circuit boards (PCBs) in the two independent workshops. To determine the potential environmental contamination, the noise, the heavy metals (Cu, Cd, Pb), and the environmental impacts of the e-waste recycling processes in the two workshops of the mobile plant have been evaluated in this paper. This study determined that when control measures are employed, the noise within the two workshops (<80 dB) will meet the national standards. In the CRT workshop, Pb was the most polluting metal, with 2.3 μg/m(3) and 10.53 mg/g in the air and floor dust, respectively. The result of a health risk assessment shows that noncancerous effects are possible for Pb (hazard index (HI) = 3.54 in the CRT workshop and HI = 1.27 in the PCB workshop). The carcinogenic risks to workers for Cd are relatively light in both the workshops. From the results of life cycle assessment (LCA), it can be seen that there was an environmental benefit from the e-waste recycling process as a whole.

  12. Study and evaluation of a PCB-MEMS liquid microflow sensor.

    PubMed

    Petropoulos, Anastasios; Kaltsas, Grigoris

    2010-01-01

    This paper presents the evaluation of a miniature liquid microflow sensor, directly integrated on a PCB. The sensor operation is based on the convective heat transfer principle. The heating and sensing elements are thin Pt resistors which are in direct electrical contact with the external copper tracks of the printed circuit board. Due to the low thermal conductivity of the substrate material, a high degree of thermal isolation is obtained which improves the operating characteristics of the device. The sensor is able to operate under both the hot-wire and the calorimetric principle. In order to fully exploit the temperature distribution in the flowing liquid, multiple sensing elements are positioned in various distances from the heater. A special housing was developed which allowed implementation of the sensor into tubes of various cross sectional areas. The sensor sensitivity and measurement range as a function of the sensing element distance were quantified. A minimum resolution of 3 μL/min and a measurement flow range up to 500 μL/min were achieved.

  13. Evaluation and interconversion of various indicator PCB schemes for ∑PCB and dioxin-like PCB toxic equivalent levels in fish.

    PubMed

    Gandhi, Nilima; Bhavsar, Satyendra P; Reiner, Eric J; Chen, Tony; Morse, Dave; Arhonditsis, George B; Drouillard, Ken G

    2015-01-06

    Polychlorinated biphenyls (PCBs) remain chemicals of concern more than three decades after the ban on their production. Technical mixture-based total PCB measurements are unreliable due to weathering and degradation, while detailed full congener specific measurements can be time-consuming and costly for large studies. Measurements using a subset of indicator PCBs (iPCBs) have been considered appropriate; however, inclusion of different PCB congeners in various iPCB schemes makes it challenging to readily compare data. Here, using an extensive data set, we examine the performance of existing iPCB3 (PCB 138, 153, and 180), iPCB6 (iPCB3 plus 28, 52, and 101) and iPCB7 (iPCB6 plus 118) schemes, and new iPCB schemes in estimating total of PCB congeners (∑PCB) and dioxin-like PCB toxic equivalent (dlPCB-TEQ) concentrations in sport fish fillets and the whole body of juvenile fish. The coefficients of determination (R(2)) for regressions conducted using logarithmically transformed data suggest that inclusion of an increased number of PCBs in an iPCB improves relationship with ∑PCB but not dlPCB-TEQs. Overall, novel iPCB3 (PCB 95, 118, and 153), iPCB4 (iPCB3 plus 138) and iPCB5 (iPCB4 plus 110) presented in this study and existing iPCB6 and iPCB7 are the most optimal indicators, while the current iPCB3 should be avoided. Measurement of ∑PCB based on a more detailed analysis (50+ congeners) is also overall a good approach for assessing PCB contamination and to track PCB origin in fish. Relationships among the existing and new iPCB schemes have been presented to facilitate their interconversion. The iPCB6 equiv levels for the 6.5 and 10 pg/g benchmarks of dlPCB-TEQ05 are about 50 and 120 ng/g ww, respectively, which are lower than the corresponding iPCB6 limits of 125 and 300 ng/g ww set by the European Union.

  14. Swimming against the PCB tide

    SciTech Connect

    Stone, R.

    1992-02-14

    Although no PCBs have been manufactured in the US and other industrialized countries for years, the chemicals are still very much with us; they are extremely long-lived. And only about 1% of the total PCBs produced have reached the oceans so far. PCBs and related organohalogens that have entered the oceans are making their way through the food chain into marine animals. As a result the animals are becoming more prone to a variety of ailments, including reproductive abnormalities and immune suppression that makes them more susceptible to disease. Unless something is done to prevent further contamination by organohalogens such as PCB, many species of ocean mammals might become extinct and some species of fish inedible. Several scientists officially launched a campaign to solicit funds for a 3-year research project aimed at determining just how serious PCB and other organohalogen problems are in the oceans.

  15. PCB metabolism by ectomycorrhizal fungi

    SciTech Connect

    Donnelly, P.K.; Fletcher, J.S.

    1995-04-01

    Since 1976 the use of polychlorinated biphenyls (PCBs) has been banned in the U.S. Prior to this, commercial mixtures (Aroclors) had been used extensively as an industrial lubricant because of their nonflammable, nonreactive properties. These same properties are responsible for their persistent in the environment where they bind to soil particles and resist biodegradation. Decontamination of PCB-laden soil is expensive with excavation followed by either storage or incineration as the primary means of remediation. The use of microorganisms for PCB bioremediation has been gaining popularity in the past few years. Bacteria and/or fungi isolated from environmental samples have been used to degrade PCBs under laboratory conditions, but in field trials they have not been as effective. The most common explanation for the poor performance of PCB-degrading organisms introduced at contaminated sites is that they do not compete well with the existing populations. Plant-ectomycorrhizal systems may overcome this problem. Introduction and cultivation of a known host plant at a contaminated site has the potential of providing a survival advantage for ectomycorrhizal fungi that normally colonize the roots of the introduced plant. Ectomycorrhizal fungi exist naturally in the soil and normally grow in association with the roots of a host plant in a mutualistic symbiotic relationship. Preliminary in vitro examination of this group of fungi for their ability to enzymatically degrade xenobiotics is very promising. In vivo studies have shown that some of these fungi have the ability to degrade chlorinated, aromatic compounds, such as 2,4-D and atrazine. The aspect of ectomycorrhizal metabolism was investigated further in the current study by determining the ability of 21 different fungi to metabolize 19 different PCB congeners with varying chlorine content and substitution patterns. 13 refs., 1 fig., 2 tabs.

  16. Recent PCB accidents in Finland.

    PubMed Central

    Elo, O; Vuojolahti, P; Janhunen, H; Rantanen, J

    1985-01-01

    Twenty-eight polychlorinated biphenyl (PCB) accidents were recorded during a 1-year period in Finland. They comprised leaks, fires or explosions of capacitors. Some of the explosions and fires gave rise to high concentrations of PCBs in air and of PCBs and tetrachlorodibenzofurans (TCDFs), including 2,3,7,8-TCDF, on surfaces. One large explosion is described in detail, and biomedical data and findings of this case are compared with those of smaller accidents in Finland. PMID:3928359

  17. Multiple mechanisms of PCB neurotoxicity

    SciTech Connect

    Carpenter, D.O.; Stoner, C.T.; Lawrence, D.A.

    1996-12-31

    Polychlorinated biphenyls (PCBs) have been implicated in cancer, but many of the symptoms in humans exposed to PCBs are related to the nervous system and behavior. We demonstrated three different direct mechanisms whereby PCBs are neurotoxic in rats. By using flow cytometry, we demonstrated that the orthosubstituted PCB congener 2,4,4{prime}, but neither TCDD nor the coplanar PCB congener 3,4,5,3{prime},4{prime}, causes rapid death of cerebellar granule cells. The ortho-substituted congener 2,4,4{prime} reduced long-term potentiation, an indicator of cognitive potential, in hippocampal brain slices, but a similar effect was observed for the coplanar congener 3,4,3{prime},4{prime}, indicating that this effect may be caused by both ortho- and coplanar congeners by mechanisms presumably not mediated via the Ah receptor. It was previously shown that some ortho-substituted PCB congeners cause a reduction in levels of the neurotransmitter dopamine, and we present in vitro and in vivo evidence that this is due to reduction of synthesis of dopamine via inhibition of the enzyme tyrosine hydroxylase. Thus, PCBs have a variety of mechanisms of primary neurotoxicity, and neurotoxicity is a characteristic of ortho-substituted, non-dioxin-like congeners as well as some coplanar congeners. The relative contribution of each of these mechanisms to the loss of cognitive function in humans exposed to PCBs remains to be determined. 42 refs., 3 figs., 1 tab.

  18. PCB (Polychlorinated Biphenyls) retrofill: Fact or fiction

    SciTech Connect

    Seifert, G.D.

    1990-01-01

    PCB transformers changes form the fire safety engineers friend to the environmental engineers worst nightmare, when it became apparent that PCB filled devices are a source of highly toxic chemicals when they are burned improperly. This concern, combined with new regulations, is prompting engineers worldwide to actively plan and design PCB replacements. The two most commonly used PCB mitigation methods are retrofill and retrofit. This report will address retrofill only and is directed toward environmental concerns, facility interfaces, outage requirements, and application questions. This information is offered to help engineers make informed decisions regarding the best way to replace PCB transformers. This overview also addresses whether PCB retrofill is a viable fact'' or is it fiction'' without merit. 3 figs.

  19. Serum PCB levels and congener profiles among teachers in PCB-containing schools: a pilot study

    PubMed Central

    2011-01-01

    Background PCB contamination in the built environment may result from the release of PCBs from building materials. The significance of this contamination as a pathway of human exposure is not well-characterized, however. This research compared the serum PCB concentrations, and congener profiles between 18 teachers in PCB-containing schools and referent populations. Methods Blood samples from 18 teachers in PCB-containing schools were analyzed for 57 PCB congeners. Serum PCB concentrations and congener patterns were compared between the teachers, to the 2003-4 NHANES (National Health and Nutrition Examination Survey) data, and to data from 358 Greater Boston area men. Results Teachers at one school had higher levels of lighter (PCB 6-74) congeners compared to teachers from other schools. PCB congener 47 contributed substantially to these elevated levels. Older teachers (ages 50-64) from all schools had higher total (sum of 33 congeners) serum PCB concentrations than age-comparable NHANES reference values. Comparing the teachers to the referent population of men from the Greater Boston area (all under age 51), no difference in total serum PCB levels was observed between the referents and teachers up to 50 years age. However, the teachers had significantly elevated serum concentrations of lighter congeners (PCB 6-74). This difference was confirmed by comparing the congener-specific ratios between groups, and principal component analysis showed that the relative contribution of lighter congeners differed between the teachers and the referents. Conclusions These findings suggest that the teachers in the PCB-containing buildings had higher serum levels of lighter PCB congeners (PCB 6-74) than the referent populations. Examination of the patterns, as well as concentrations of individual PCB congeners in serum is essential to investigating the contributions from potential environmental sources of PCB exposure. PMID:21668970

  20. Failure Analysis of Board-Level Sn-Ag-Cu Solder Interconnections Under JEDEC Standard Drop Test

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Xi, Jing Si; Liu, Pin Kuan; Ding, Han

    2013-09-01

    This work investigates the board-level drop reliability of printed circuit boards (PCBs) assembled using three chip-size packages subjected to Joint Electron Device Engineering Council (JEDEC) standard drop test condition B. The acceleration and dynamic strain responses at several locations of the board-level package in the time and frequency domain are comprehensively investigated. The results in the time domain suggest that the dynamic response of the board-level package has two phases: forced vibration and free vibration. The maximum response occurs at the first half free vibration cycle. The acceleration response at the center of the PCB is larger than at the edges, whereas the dynamic strain response is just the opposite. The results in the frequency domain show that the first mode is fundamental. In addition, failure analysis is performed using the dye-and-pry test and cross-section test, suggesting that the brittle cracking occurs at the layer between the integrated circuit (IC) pad and the solder, not only through intermetallic compound (IMC) but also along the surface between the IC pad and IMC.

  1. Supreme Court of the United States Syllabus. National Labor Relations Board v. Yeshiva University, Certiorari to the United States Court of Appeals for the Second Circuit.

    ERIC Educational Resources Information Center

    Supreme Court of the U. S., Washington, DC.

    The opinion of the Supreme Court regarding the case of the National Labor Relations Board v. Yeshiva University is presented. The University opposed a petition of the faculty union seeking certification as bargaining agent for the full-time faculty members of certain schools. Refusal by the University was on the ground that all of its faculty…

  2. ENVIROGARD™ PCB TEST KIT, MILLIPORE, INC. - INNOVATIVE TECHNOLOGY EVALUATION REPORT

    EPA Science Inventory

    The Envirogard™ polychlorinated biphenyl (PCB) immunoassay test kit rapidly analyzes for PCB concentrations in soils. Soils samples are extracted using methanol; extracts and calibration solutions are added to test tubes coated with antibodies that bind PCB molecules. The soil ex...

  3. ENVIROGARD™ PCB TEST KIT, MILLIPORE, INC. - INNOVATIVE TECHNOLOGY EVALUATION REPORT

    EPA Science Inventory

    The Envirogard™ polychlorinated biphenyl (PCB) immunoassay test kit rapidly analyzes for PCB concentrations in soils. Soils samples are extracted using methanol; extracts and calibration solutions are added to test tubes coated with antibodies that bind PCB molecules. The soil ex...

  4. PCB tester selection for future systems. Volume 1. Final report, August 1989-June 1991

    SciTech Connect

    Schmitt, W.

    1992-06-01

    This report describes a computer program (to run on an IBM compatible PC) designed to aid in the selection of a PCB tester, given the characteristics of the PC board to be tested. The program contains a limited data base of PCB testers, and others may be added easily. This report also provides a specification for a limited family of PCB testers to fill the gap between what the U.S. Air Force is expected to need and what is expected to be available within the next four to six years. The parameters used in the computer program and the specification are based on a survey of military and commercial PCBs - both those now available and those expected to come on line within the next four to six years. The results of the survey are covered in volume 2 - available from DTIC. Automatic Test Equipment, Technology Forecast, Air Force Avionics.

  5. PCB tester selection for future systems. Volume 2. Final report, August 1989-June 1991

    SciTech Connect

    Schmitt, W.

    1992-06-01

    This report describes a computer program (to run on an IBM compatible PC) designed to aid in the selection of a PCB tester, given the characteristics of the PC board to be tested. The program contains a limited data base of PCB testers, and others may be added easily. This report also provides a specification for a limited family of PCB testers to fill the gap between what the U.S. Air Force is expected to need and what is expected to be available within the next four to six years. The parameters used in the computer program and the specification are based on a survey of military and commercial PCBs - both those now available and those expected to come on line within the next four to six years. The results of the survey are covered in volume 2 - available from DTIC. Automatic Test Equipment, Technology Forecast, Air Force Avionics.

  6. PCB dechlorination in anaerobic soil slurry reactors

    SciTech Connect

    Klasson, K.T.; Evans, B.S.

    1993-11-29

    Many industrial locations, including the US Department of Energy`s, have identified needs for treatment of polychlorinated biphenyl (PCB) wastes and remediation of PCB-contaminated sites. Biodegradation of PCBs is a potentially effective technology for the treatment of PCB-contaminated soils and sludges, including mixed wastes; however, a practical remediation technology has not yet been demonstrated. In laboratory experiments, soil slurry bioreactors inoculated with microorganisms extracted from PCB-contaminated sediments from the Hudson River have been used to obtain anaerobic dechlorination of PCBS. The onset of dechlorination activity can be accelerated by addition of nutritional amendments and inducers. After 15 weeks of incubation with PCB-contaminated soil and nutrient solution, dechlorination has been observed under several working conditions. The best results show that the average chlorine content steadily dropped from 4.3 to 3.5 chlorines per biphenyl over a 15-week period.

  7. Composite compatible printed circuit technology for the distribution of electrical signals

    NASA Astrophysics Data System (ADS)

    Treen, Andrew; Morris, G.; Fixter, G.; Farmer, S.

    1996-02-01

    The combination of sensing and actuating technologies within composite structures without affecting their structural performance is a major problem in the development, and acceptance, of smart materials technologies. A technique has been developed which uses a woven polyester cloth material, patterned with thin, integral, conductors to create a flexible, composite compatible, method of distributing electrical power throughout a structural panel. The cloths can be considered as printed circuit boards for inclusion within composite structures. It is capable of distributing power throughout a structure in a predetermined, controlled manner. This allows embedded components to be accurately positioned and many external connections to be made to the structure, via a PCB like connector, at a convenient position. The technique therefore considerably simplifies the construction of complex systems. The technology is demonstrated with reference to a piezoelectric actuated composite structure.

  8. Optimizing the Design of Avionics Lightning Suppression Circuits

    NASA Astrophysics Data System (ADS)

    McCreary, Clay Allen

    This dissertation documents research into optimizing the design of lightning suppression circuits for electronic equipment used on aircraft (avionics). Aircraft manufacturers are increasingly using carbon composite material for the fabrication of the airframe instead of aluminum, and avionics have become more integrated. This has resulted in avionics with higher signal density at the interface being exposed to transients with wider pulse widths and increased levels from the indirect effects of lightning. This dissertation details the development of techniques to select the smallest components and minimum printed circuit board trace dimensions that can tolerate given lightning transient levels. Also, there is a desire to upgrade existing avionics to tolerate the more severe indirect effects of lightning requirements for composite aircraft. This requires evaluation of the immunity of existing designs to new transient levels and different waveforms than those to which they are certified. This evaluation determines if additional protection is needed. The evaluation technique is described, and methods for providing additional protection are given within this document. Lastly, graphical user interfaces (GUI) are created to perform all of the calculations for component selection, minimum PCB trace width, and the first step in evaluating existing designs against new requirements.

  9. Recycled hierarchical tripod-like CuCl from Cu-PCB waste etchant for lithium ion battery anode.

    PubMed

    Liu, Song; Hou, Hongying; Liu, Xianxi; Duan, Jixiang; Yao, Yuan; Liao, Qishu; Li, Jing; Yang, Yunzhen

    2017-02-15

    Hierarchical CuCl with high economic value added (EVA) was successfully recycled with 85% recovery from the acid Cu printed circuit board (Cu-PCB) waste etchant via facile liquid chemical reduction. The micro-structure and morphology of the recycled hierarchical CuCl were systematically characterized in terms of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). Furthermore, the corresponding electrochemical performances as lithium ion battery (LIB) anode were also investigated in terms of galvanostatic charge/discharge, cyclic voltammetry (CV) and AC impedance. As expected, the recycled CuCl displayed a hierarchical tripod-like structure and large specific surface area of 21.2m(2)/g. As the anode in LIB, the reversible discharge capacity was about 201.4 mAh/g even after 100 cycles, implying the satisfactory cycle performance. Clearly, the satisfactory results may open a new avenue to develop the sustainable industry, which is very important in terms of both the resource recovery and the environmental protection.

  10. Chamber study of polychlorinated biphenyl {PCB} emissions ...

    EPA Pesticide Factsheets

    The sorption of airborne polychlorinated biphenyls (PCBs) by twenty building materials and their subsequent re-emission (desorption) from concrete were investigated using two 53-L environmental chambers connected in series with a field-collected caulk in the source chamber serving as a stable source of PCBs and building materials in the test chamber. During the tests, the PCB concentrations in the outlet air of the test chamber were monitored and the building materials were removed from the test chamber at different times to determine their PCB content. Among the materials tested, a petroleum-based paint, a latex paint, and a certain type of carpet were among the strongest sinks. Solvent-free epoxy coating, certain types of flooring materials, and brick were among the weakest sinks. For a given sink material, PCB congeners with lower vapor pressures were sorbed in larger quantities. Rough estimates of the partition and diffusion coefficients were obtained by applying a sink model to the data acquired from the chamber studies. A desorption test with the concrete panels showed that re-emission is a slow process, suggesting that PCB sinks, e.g. concrete, can release PCBs into the air for a prolonged period of time (years or decades). This study could fill some of the data gaps associated with the characterization of PCB sinks in contaminated buildings. This paper summarizes the laboratory research results for PCB transport from primary sources to PCB sinks, includ

  11. PCB126 Inhibits Adipogenesis of Human Preadipocytes

    PubMed Central

    Gadupudi, Gopi; Gourronc, Francoise A.; Ludewig, Gabriele; Robertson, Larry W.; Klingelhutz, Aloysius J.

    2014-01-01

    Emerging evidence indicates that persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), are involved in the development of diabetes. Dysfunctional adipocytes play a significant role in initiating insulin resistance. Preadipocytes make up a large portion of adipose tissue and are necessary for the generation of functional mature adipocytes through adipogenesis. PCB126 is a dioxin-like PCB and a potent aryl hydrocarbon receptor (AhR) agonist. We hypothesized that PCB126 may be involved in the development of diabetes through disruption of adipogenesis. Using a newly developed human preadipocyte cell line called NPAD (Normal PreADipocytes), we found that exposure of preadipocytes to PCB126 resulted in significant reduction in their subsequent ability to fully differentiate into adipocytes, more so than when the cells were exposed to PCB126 during differentiation. Reduction in differentiation by PCB126 was associated with downregulation of transcript levels of a key adipocyte transcription factor, PPARγ, and late adipocyte differentiation genes. An AhR antagonist, CH223191, blocked this effect. These studies indicate that preadipocytes are particularly sensitive to the effects of PCB126 and suggest that AhR activation inhibits PPARγ transcription and subsequent adipogenesis. Our results validate the NPAD cell line as a useful model for studying the effects of POPs on adipogenesis. PMID:25304490

  12. Chamber study of polychlorinated biphenyl (PCB) emissions ...

    EPA Pesticide Factsheets

    The sorption of airborne polychlorinated biphenyls (PCBs) by twenty building materials and their subsequent re-emission (desorption) from concrete were investigated using two 53-L environmental chambers connected in series with a field-collected caulk in the source chamber serving as a stable source of PCBs and building materials in the test chamber. During the tests, the PCB concentrations in the outlet air of the test chamber were monitored and the building materials were removed from the test chamber at different times to determine their PCB content. Among the materials tested, a petroleum-based paint, a latex paint, and a certain type of carpet were among the strongest sinks. Solvent-free epoxy coating, certain types of flooring materials, and brick were among the weakest sinks. For a given sink material, PCB congeners with lower vapor pressures were sorbed in larger quantities. Rough estimates of the partition and diffusion coefficients were obtained by applying a sink model to the data acquired from the chamber studies. A desorption test with the concrete panels showed that re-emission is a slow process, suggesting that PCB sinks, e.g. concrete, can release PCBs into the air for a prolonged period of time (years or decades). This study could fill some of the data gaps associated with the characterization of PCB sinks in contaminated buildings. This paper summarizes the laboratory research results for PCB transport from primary sources to PCB sinks, includ

  13. No-warp potted circuits

    NASA Technical Reports Server (NTRS)

    Robinson, W. W.

    1979-01-01

    Sponge inserts compensate for potting-compound expansion and relieve thermal stresses on circuit boards. Technique quality of production runs on PC boards intended for applications in environments less severe than those for aerospace equipment. Pads reduce weight of modules because they weigh far less than potting compound they displace.

  14. No-warp potted circuits

    NASA Technical Reports Server (NTRS)

    Robinson, W. W.

    1979-01-01

    Sponge inserts compensate for potting-compound expansion and relieve thermal stresses on circuit boards. Technique quality of production runs on PC boards intended for applications in environments less severe than those for aerospace equipment. Pads reduce weight of modules because they weigh far less than potting compound they displace.

  15. BEHAVIORAL ASSESSMENTS OF ADULTS RATS EXPOSED PERINATALLY TO PCB153.

    EPA Science Inventory

    Ortho-substituted polychlorinated biphenyl (PCB) congeners are more neurotoxic in vitro than are non-ortho-substituted PCB congeners. We selected PCB153, a common ortho-substituted PCB congener, to evaluate the neurobehavioral toxicity of this class of PCBs in vivo. Pregnant fema...

  16. BEHAVIORAL ASSESSMENTS OF ADULTS RATS EXPOSED PERINATALLY TO PCB153.

    EPA Science Inventory

    Ortho-substituted polychlorinated biphenyl (PCB) congeners are more neurotoxic in vitro than are non-ortho-substituted PCB congeners. We selected PCB153, a common ortho-substituted PCB congener, to evaluate the neurobehavioral toxicity of this class of PCBs in vivo. Pregnant fema...

  17. Silicon Carbide Integrated Circuit Chip

    NASA Image and Video Library

    2015-02-17

    A multilevel interconnect silicon carbide integrated circuit chip with co-fired ceramic package and circuit board recently developed at the NASA GRC Smart Sensors and Electronics Systems Branch for high temperature applications. High temperature silicon carbide electronics and compatible packaging technologies are elements of instrumentation for aerospace engine control and long term inner-solar planet explorations.

  18. DEMONSTRATION BULLETIN: CLOR-N-SOIL PCB TEST KIT L2000 PCB/CHLORIDE ANALYZER - DEXSIL CORP.

    EPA Science Inventory

    DEXSIL CORP(Environmental Test Kits)The Dexsil Corporation (Dexsil) produces two test kits that detect polychlorinated biphenyls (PCB) in soil: the Dexsil Clor-N-Soil PCB Screening Kit, and the Dexsil L2000 PCB/Chloride Analyzer. The Dexsil Clor-N-Soil PCB Screening Kit extr...

  19. DEMONSTRATION BULLETIN: CLOR-N-SOIL PCB TEST KIT L2000 PCB/CHLORIDE ANALYZER - DEXSIL CORP.

    EPA Science Inventory

    DEXSIL CORP(Environmental Test Kits)The Dexsil Corporation (Dexsil) produces two test kits that detect polychlorinated biphenyls (PCB) in soil: the Dexsil Clor-N-Soil PCB Screening Kit, and the Dexsil L2000 PCB/Chloride Analyzer. The Dexsil Clor-N-Soil PCB Screening Kit extr...

  20. Board Saver for Use with Developmental FPGAs

    NASA Technical Reports Server (NTRS)

    Berkun, Andrew

    2009-01-01

    A device denoted a board saver has been developed as a means of reducing wear and tear of a printed-circuit board onto which an antifuse field programmable gate array (FPGA) is to be eventually soldered permanently after a number of design iterations. The need for the board saver or a similar device arises because (1) antifuse-FPGA design iterations are common and (2) repeated soldering and unsoldering of FPGAs on the printed-circuit board to accommodate design iterations can wear out the printed-circuit board. The board saver is basically a solderable/unsolderable FPGA receptacle that is installed temporarily on the printed-circuit board. The board saver is, more specifically, a smaller, square-ring-shaped, printed-circuit board (see figure) that contains half via holes one for each contact pad along its periphery. As initially fabricated, the board saver is a wider ring containing full via holes, but then it is milled along its outer edges, cutting the via holes in half and laterally exposing their interiors. The board saver is positioned in registration with the designated FPGA footprint and each via hole is soldered to the outer portion of the corresponding FPGA contact pad on the first-mentioned printed-circuit board. The via-hole/contact joints can be inspected visually and can be easily unsoldered later. The square hole in the middle of the board saver is sized to accommodate the FPGA, and the thickness of the board saver is the same as that of the FPGA. Hence, when a non-final FPGA is placed in the square hole, the combination of the non-final FPGA and the board saver occupy no more area and thickness than would a final FPGA soldered directly into its designated position on the first-mentioned circuit board. The contact leads of a non-final FPGA are not bent and are soldered, at the top of the board saver, to the corresponding via holes. A non-final FPGA can readily be unsoldered from the board saver and replaced by another one. Once the final FPGA design