WorldWideScience

Sample records for circuit boards computers

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

    International Nuclear Information System (INIS)

    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

  2. Primer printed circuit boards

    CERN Document Server

    Argyle, Andrew

    2009-01-01

    Step-by-step instructions for making your own PCBs at home. Making your own printed circuit board (PCB) might seem a daunting task, but once you master the steps, it's easy to attain professional-looking results. Printed circuit boards, which connect chips and other components, are what make almost all modern electronic devices possible. PCBs are made from sheets of fiberglass clad with copper, usually in multiplelayers. Cut a computer motherboard in two, for instance, and you'll often see five or more differently patterned layers. Making boards at home is relatively easy

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Ivănuş R.C.

    2010-06-01

    Full Text Available 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.

  5. Recovery of tin and copper by recycling of printed circuit boards from obsolete computers

    Directory of Open Access Journals (Sweden)

    L. A. Castro

    2009-12-01

    Full Text Available This paper presents the experimental results for the leaching of printed circuit boards (PCB from obsolete computers for extracting and recovering tin and copper by means of leaching followed by precipitation. Printed circuit boards were dismantled, cut into small pieces, and fed into a cylinder mill. The powder obtained was leached by using the aqueous solutions 2.18N H2SO4, 2.18N H2SO4 + 3.0N HCl, 3.0N HCl, and 3.0N HCl + 1.0N HNO3. The lowest values for the percentage of metal extraction were obtained with 2.18N H2SO4 (2.7% for Sn and lower than 0.01% for Cu, while the 3.0N HCl + 1.0N HNO3 leach system exhibited an extraction of 98% for Sn and 93% for Cu. Precipitates were obtained at different pH values by neutralizing the leach liquors using NaOH. The 3.0N HCl + 1.0N HNO3 leach system presented the highest recovery values from the powder feed (84.1% for Sn and 31.9% for Cu, as well as from the leach liquor (85.8% for Sn and 34.3% for Cu.

  6. Addressing Rural Library Technology Budgets with Single Board Computers: Testing the APC 8950 Rock Circuit Board Computer for Patron Access

    Directory of Open Access Journals (Sweden)

    Michael D. Wells

    2014-04-01

    Full Text Available Over the last decade, libraries have faced enormous budgetary challenges when it comes to implementing new technologies. These challenges are very pronounced in rural areas where libraries struggle to develop and define a path for purchasing and replacing systems that have become outdated. The author attempted to create a unit to replace aging OPAC terminals and to provide a low cost computing option for budget constrained rural libraries. The initial attempt detailed in this paper involved purchasing and configuring an APC 8950 Rock single board computer. Unfortunately, due to limitations of this APC unit’s existing Android based operating system, the initial effort failed to yield a computer that could be used in a library by average patrons. Future plans are outlined for the development of a second system using the more broadly accepted Raspberry Pi platform. The success of this technological endeavor may empower libraries and patrons in their communities to have more control of the technology they develop and use in the future.

  7. Training Circuit Boards

    Science.gov (United States)

    1986-01-01

    Young Electronics Company's new product is a testboard developed by the Jet Propulsion Laboratory as a tool for training and qualifying personnel in board assembly and in the art of soldering components without damaging boards or components. The boards are used for pre- employment testing and employee requalification.

  8. A guide to printed circuit board design

    CERN Document Server

    Hamilton, Charles

    1984-01-01

    A Guide to Printed Circuit Board Design discusses the basic design principles of printed circuit board (PCB). The book consists of nine chapters; each chapter provides both text discussion and illustration relevant to the topic being discussed. Chapter 1 talks about understanding the circuit diagram, and Chapter 2 covers how to compile component information file. Chapter 3 deals with the design layout, while Chapter 4 talks about preparing the master artworks. The book also covers generating computer aided design (CAD) master patterns, and then discusses how to prepare the production drawing a

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

    Science.gov (United States)

    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. PMID:17981393

  10. CAD-CAM printed circuit board design

    Science.gov (United States)

    Agy, W. E.

    A step-by-step procedure for a printed circuit design achieved by CAD is presented. The operator at the interactive CRT station moves a stylus across a graphics tablet and intersperses commands which result in computer-generated pictorial forms on the screen that were drawn on the pad. Standard symbols are used for commands allowing, for instance, connections to be made of specific types in certain locations, which can be automatically edited from a materials list. An entire network of drawn lines can be referenced by a signal name for recall, and a finished circuit schematic can be checked for designs rules compliance, including fault reporting in terms of designator/pin number. A map may be present delineating the boundaries of the circuitry area, and previously completed circuitry segments can be recalled for piece-by-piece assembly of the circuit board.

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

    Science.gov (United States)

    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. PMID:25636979

  12. Digital circuit boards mach 1 GHz

    CERN Document Server

    Morrison, Ralph

    2012-01-01

    A unique, practical approach to the design of high-speed digital circuit boards The demand for ever-faster digital circuit designs is beginning to render the circuit theory used by engineers ineffective. Digital Circuit Boards presents an alternative to the circuit theory approach, emphasizing energy flow rather than just signal interconnection to explain logic circuit behavior. The book shows how treating design in terms of transmission lines will ensure that the logic will function, addressing both storage and movement of electrical energy on these lines. It cove

  13. Sustainability issues in circuit board recycling

    DEFF Research Database (Denmark)

    Legarth, Jens Brøbech; Alting, Leo; Baldo, Gian Luca

    1995-01-01

    The resource recovery and environmental impact issues of printed circuit board recycling by secondary copper smelters are discussed. Guidelines concerning material selection for circuit board manufacture and concerning the recycling processes are given to enhance recovery efficiency and to lower...... the impacts on the external environment from recycling...

  14. Design and Implementation of A Circuit Board Calibration System

    Directory of Open Access Journals (Sweden)

    Bai Hang

    2016-01-01

    Full Text Available With the development of science and technology, the traditional artificial detection methods cannot meet the requirements of modern equipment testing and calibration. Combined with the actual demand, a kind of circuit boards calibration system are put forward. It can to realize automatic testing and calibration of the circuit boards. Many functions of the calibration system such as automatic testing, self-test and monitoring are summarized. The hardware is introduced which including the industrial computer system, calibration adapter and so on. Then, development platform, the thought of program design and the structure of the software are introduced in detail. The function of automatic calibration to specific circuit boards are realized. Because the system has good commonality and easy to extend to upgrade, the development ideas and experiences can be applied to similar circuit boards automatic testing system.

  15. An advanced study on the hydrometallurgical processing of waste computer printed circuit boards to extract their valuable content of metals.

    Science.gov (United States)

    Birloaga, Ionela; Coman, Vasile; Kopacek, Bernd; Vegliò, Francesco

    2014-12-01

    This study refers to two chemical leaching systems for the base and precious metals extraction from waste printed circuit boards (WPCBs); sulfuric acid with hydrogen peroxide have been used for the first group of metals, meantime thiourea with the ferric ion in sulfuric acid medium were employed for the second one. The cementation process with zinc, copper and iron metal powders was attempted for solutions purification. The effects of hydrogen peroxide volume in rapport with sulfuric acid concentration and temperature were evaluated for oxidative leaching process. 2M H2SO4 (98% w/v), 5% H2O2, 25 °C, 1/10 S/L ratio and 200 rpm were founded as optimal conditions for Cu extraction. Thiourea acid leaching process, performed on the solid filtrate obtained after three oxidative leaching steps, was carried out with 20 g/L of CS(NH2)2, 6g/L of Fe(3+), 0.5M H2SO4, The cross-leaching method was applied by reusing of thiourea liquid suspension and immersing 5 g/L of this reagent for each other experiment material of leaching. This procedure has lead to the doubling and, respectively, tripling, of gold and silver concentrations into solution. These results reveal a very efficient, promising and environmental friendly method for WPCBs processing. PMID:25242605

  16. 47 CFR 15.32 - Test procedures for CPU boards and computer power supplies.

    Science.gov (United States)

    2010-10-01

    ... result in a complete personal computer system. If the oscillator and the microprocessor circuits are... microprocessor circuits are contained on separate circuit boards, both boards, typical of the combination...

  17. Vacuum pyrolysis of waste print circuit board

    Institute of Scientific and Technical Information of China (English)

    GAN Ge; CHEN Lie-qiang; PENG Shao-hong; CAI Ming-zhao

    2005-01-01

    Waste print circuit board containing 11.38% Br was pyrolyzed in vacuum.Thermal stability of waste print circuit board was studied under vacuum condition by thermo-gravimetry(TG). Vacuum pyrolysis of WPCB was studied emphasizing on the kinetics of WPCB pyrolysis reactions. Based on the TG results, a kinetic model was proposed. Kinetic parameters were calculated for reaction with this model including all stages of decomposition. The average activation energy is 68 k J/mol with reaction order 3. These findings provide new insights into the WPCB thermal decomposition and useful data for rational design and operation of pyrolysis.

  18. Pyrolysis of Waste Printed Circuit Board Particles

    OpenAIRE

    Şule Atasever; Pınar A. Bozkurt; Muammer Canel

    2015-01-01

    Electrical and electronic apparatus and instruments which are obsolete value in use or completion of the life can be defined as e-waste. E-waste is one of the fastest growing types of hazardous waste. Printed circuit boards a major component of this waste. In this study, printed circuit board particles of mobile phone (MPCB) were used as electronic waste. MPCB waste was obtained from a local electronic waste factory. The elemental analysis and ICP-MS analysis were performed on these electroni...

  19. Computer simulation of the pneumatic separator in the pneumatic-electrostatic separation system for recycling waste printed circuit boards with electronic components.

    Science.gov (United States)

    Xue, Mianqiang; Xu, Zhenming

    2013-05-01

    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. PMID:23560940

  20. Improving Heat Transfer Performance of Printed Circuit Boards

    Science.gov (United States)

    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.

  1. Laser prototyping of printed circuit boards

    Science.gov (United States)

    Nowak, M. R.; Antończak, A. J.; Kozioł, P. E.; Abramski, K. M.

    2013-09-01

    This paper describes the application of laser micromachining to rapid prototyping of printed circuit boards (PCB) using nano-second lasers: the solid-state Nd:YAG (532/1064 nm) laser and the Yb:glass fiber laser (1060 nm). Our investigations included tests for various mask types (synthetic lacquer, light-sensitive emulsion and tin). The purpose of these tests was to determine some of the basic parameters such as the resolution of PCB prototyping, speed of processing and quality of PCB mapping with commonly available laser systems. Optimization of process parameters and the proposed conversion algorithm have allowed us to produce circuit boards with a resolution similar to that of the Laser Direct Imaging (LDI) technology.

  2. Developing 300°C Ceramic Circuit Boards

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  5. Separation and recovery of materials from scrap printed circuit boards

    Energy Technology Data Exchange (ETDEWEB)

    Hall, William J.; Williams, Paul T. [Energy and Resources Research Institute, The University of Leeds, Leeds LS2 9JT (United Kingdom)

    2007-09-15

    Printed circuit boards from waste computers, televisions, and mobile phones were pyrolysed in a fixed bed reactor with the aim of separating and recovering the organic and metallic materials. A selection of printed circuit boards from each of the three waste classes was pyrolysed at 800 C and the pyrolysis products were analysed using GC-FID, GC-TCD, GC-MS, GC-ECD, ICP-MS, and SEM-EDX. The pyrolysis oils contained high concentrations of phenol, 4-(1-methylethyl)phenol, and p-hydroxyphenol, as well as bisphenol A, tetrabromobisphenol A, methyl phenols, and bromophenols. The pyrolysis oils also contained significant concentrations of organo-phosphate compounds and a number of tetrabromobisphenol A pyrolysis products were also identified. The pyrolysis residues were very friable and the organic, glass fibre, and metallic fractions could easily be separated and the electrical components could easily be removed from the remains of the printed circuit boards. The ash in the residue mainly consisted of copper, calcium, iron, nickel, zinc, and aluminium, as well as lower concentrations of valuable metals such as gallium, bismuth, silver, and gold, silver was present in particularly high concentrations. Many other metals were also identified in the ash by ICP-MS and SEM EDX. The pyrolysis gases mainly consisted of CO{sub 2} and CO but all of the C{sub 1}-C{sub 4} alkanes and alkenes were present, as were some inorganic halogens. (author)

  6. Computer Science and Technology Board

    Energy Technology Data Exchange (ETDEWEB)

    Blumenthal, M.S.

    1990-01-01

    The Computer Science and Technology Board (CSTB) meets three times a year to consider scientific and policy issues in computer science as well as relevant problems in associated technologies. The objectives of the Board include: initiating studies involving computer science and technology as a critical national resource; responding to requests from the government, nonprofit foundations, and industry for advice on computer science and technology; promoting the health of the technology and other fields of pure and applied science and technology; and providing a base of expertise within the NRC in the area of computer science and technology.

  7. Polymer circuit boards fabricated by ultrasonic hot embossing

    International Nuclear Information System (INIS)

    In this paper, a novel polymer circuit board fabricated by ultrasonic hot embossing is presented. Conductive paths are generated by ultrasonically embossing interruptions into a continuous metal layer coated onto a plastic substrate, and all electronic components are mounted onto the board in a single ultrasonic process step. With this process both the fabrication of a board and the interconnection of electronic components can be achieved in seconds. Overall dimensions of the board are determined by the size of the sonotrode of the ultrasonic machine. As a demonstrator a multivibrator circuit was built up from five resistors, two LEDs, two transistors and two capacitors. The multivibrator was tested successfully. (paper)

  8. WASTE PRINTED CIRCUIT BOARDS SEPARATION IN ELECTROSTATIC SEPARATOR

    OpenAIRE

    Branimir Fuk

    2012-01-01

    Printed circuit boards from electronic waste are very important source of precious metals by recycling. The biggest challenge is liberation and separation of useful components; thin film which contains copper, zinc, tin, lead and precious metals like silver, gold and palladium from non useful components; polymers, ceramics and glass fibbers. The paper presents results for separation of shredded printed circuit boards from TV sets in electrostatic separator. Testing where conducted with materi...

  9. Merging polygons on two-layer printed circuit board

    Directory of Open Access Journals (Sweden)

    Murov S. Yu.

    2011-12-01

    Full Text Available A method is proposed for solving the problem of connection of maximum number of isolated islands of metallized areas of the same chain, located on different layers of the printed circuit board. The method can be used in the automatic tracing of the boards.

  10. Process produces accurate registry between circuit board prints

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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 . PMID:17900802

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

    Science.gov (United States)

    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.

  13. Analog Nonvolatile Computer Memory Circuits

    Science.gov (United States)

    MacLeod, Todd

    2007-01-01

    In nonvolatile random-access memory (RAM) circuits of a proposed type, digital data would be stored in analog form in ferroelectric field-effect transistors (FFETs). This type of memory circuit would offer advantages over prior volatile and nonvolatile types: In a conventional complementary metal oxide/semiconductor static RAM, six transistors must be used to store one bit, and storage is volatile in that data are lost when power is turned off. In a conventional dynamic RAM, three transistors must be used to store one bit, and the stored bit must be refreshed every few milliseconds. In contrast, in a RAM according to the proposal, data would be retained when power was turned off, each memory cell would contain only two FFETs, and the cell could store multiple bits (the exact number of bits depending on the specific design). Conventional flash memory circuits afford nonvolatile storage, but they operate at reading and writing times of the order of thousands of conventional computer memory reading and writing times and, hence, are suitable for use only as off-line storage devices. In addition, flash memories cease to function after limited numbers of writing cycles. The proposed memory circuits would not be subject to either of these limitations. Prior developmental nonvolatile ferroelectric memories are limited to one bit per cell, whereas, as stated above, the proposed memories would not be so limited. The design of a memory circuit according to the proposal must reflect the fact that FFET storage is only partly nonvolatile, in that the signal stored in an FFET decays gradually over time. (Retention times of some advanced FFETs exceed ten years.) Instead of storing a single bit of data as either a positively or negatively saturated state in a ferroelectric device, each memory cell according to the proposal would store two values. The two FFETs in each cell would be denoted the storage FFET and the control FFET. The storage FFET would store an analog signal value

  14. Development and verification of printed circuit board toroidal transformer model

    DEFF Research Database (Denmark)

    Pejtersen, Jens; Mønster, Jakob Døllner; Knott, Arnold

    2013-01-01

    by comparing calculated parameters with 3D finite element simulations and experimental measurement results. The developed transformer model shows good agreement with the simulated and measured results. The model can be used to predict the parameters of printed circuit board toroidal transformer configurations......An analytical model of an air core printed circuit board embedded toroidal transformer configuration is presented. The transformer has been developed for galvanic isolation of very high frequency switch-mode dc-dc power converter applications. The theoretical model is developed and verified...

  15. Effective electromagnetic shielding in multilayer printed circuit boards

    Science.gov (United States)

    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

  16. Integrated optical and electronic interconnect printed circuit board manufacturing

    OpenAIRE

    Selviah, D. R.; Fernández, F. A.; Papakonstantinou, I.; Wang, K.; Bagshiahi, H.; Walker, A. C.; McCarthy, A.; Suyal, H; Hutt, D.A.; Conway, P. P.; Chappell, J.; Zakariyah, S. S.; Milward, D

    2008-01-01

    Introduction: At high bit rates copper tracks in printed circuit boards (PCBs) suffer severe loss and pulse distortion due to radiation of electromagnetic waves, dispersion and bandwidth limitations. The loss can be overcome to some extent by transmitting higher power pulses and by changing the dielectric constant and loss tangent of the PCB substrate material. However, high power pulses consume power and can cause electro-migration which reduces the board lifetime, although the copper tracks...

  17. RECYCLING OF PRINTED CIRCUIT BOARDS AIMING SILVER RECOVERY: A HYDROMETALLURGICAL ROUTE STUDY

    Directory of Open Access Journals (Sweden)

    Marcos Paulo Kohler Caldas

    2015-06-01

    Full Text Available The aim of this paper is characterize printed circuit board of computers and propose a hydrometallurgical route for silver recovery present in its composition. Initially, the printed circuit board was comminuted in both knife and hammer mills. The comminuted material was characterized by sieve analysis, chemical analysis by inductively coupled plasma optical emission spectrometry (ICP-OES and loss on ignition. Leaching tests were conducted in sulfuric acid, sulfuric acid in an oxidizing medium and nitric acid. The results indicated that the printed circuit board is mainly composed of copper (19.42%. Silver content of 0.045% was found. The route for silver recovery was leaching in sulfuric acid at 75°C for 18 hours. Then, leaching in sulfuric acid at 75°C in an oxidizing medium for 6 hours and nitric acid leaching at room temperature for 2 hours. Through of this route, 96.6% of silver was recovered.

  18. Handwritten, Soft Circuit Boards and Antennas Using Liquid Metal Nanoparticles.

    Science.gov (United States)

    Lin, Yiliang; Cooper, Christopher; Wang, Meng; Adams, Jacob J; Genzer, Jan; Dickey, Michael D

    2015-12-22

    Soft conductors are created by embedding liquid metal nanoparticles between two elastomeric sheets. Initially, the particles form an electrically insulating composite. Soft circuit boards can be handwritten by a stylus, which sinters the particles into conductive traces by applying localized mechanical pressure to the elastomeric sheets. Antennas with tunable frequencies are formed by sintering nanoparticles in microchannels.

  19. Recycling process assessment of mechanical recycling of printed circuit board

    Institute of Scientific and Technical Information of China (English)

    PAN Jun-qi; LIU Zhi-feng; LIU Guang-fu; WANG Shu-wang; HUANG Hai-hong

    2005-01-01

    A comprehensive assessment index system was established. The mechanical recycling process of printed circuit board was evaluated according to the comprehensive evaluation index system using the fuzzy analytic hierarchy process. A process assessment software system of mechanical recycling was established to evaluate different recy cling technologies. And the software system was developed in the environment of VB 6.0 and Access 2000.

  20. VLSI circuits implementing computational models of neocortical circuits.

    Science.gov (United States)

    Wijekoon, Jayawan H B; Dudek, Piotr

    2012-09-15

    This paper overviews the design and implementation of three neuromorphic integrated circuits developed for the COLAMN ("Novel Computing Architecture for Cognitive Systems based on the Laminar Microcircuitry of the Neocortex") project. The circuits are implemented in a standard 0.35 μm CMOS technology and include spiking and bursting neuron models, and synapses with short-term (facilitating/depressing) and long-term (STDP and dopamine-modulated STDP) dynamics. They enable execution of complex nonlinear models in accelerated-time, as compared with biology, and with low power consumption. The neural dynamics are implemented using analogue circuit techniques, with digital asynchronous event-based input and output. The circuits provide configurable hardware blocks that can be used to simulate a variety of neural networks. The paper presents experimental results obtained from the fabricated devices, and discusses the advantages and disadvantages of the analogue circuit approach to computational neural modelling. PMID:22342970

  1. Elemental analysis of printed circuit boards considering the ROHS regulations

    International Nuclear Information System (INIS)

    The EU RoHS Directive (2002/95/EC of the European Parliament and of the Council) bans the placing of new electrical and electronic equipment containing more than agreed levels of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) flame retardants on the EU market. It necessitates methods for the evaluation of RoHS compliance of assembled electronic equipment. In this study mounted printed circuit boards from personal computers were analyzed on their content of the three elements Cd, Pb and Hg which were limited by the EU RoHS directive. Main focus of the investigations was the influence of sample pre-treatment on the precision and reproducibility of the results. The sample preparation steps used were based on the guidelines given in EN 62321. Five different types of dissolution procedures were tested on different subsequent steps of sample treatment like cutting and milling. Elemental analysis was carried out using ICP-OES, XRF and CV-AFS (Hg). The results obtained showed that for decision-making with respect to RoHS compliance a size reduction of the material to be analyzed to particles ≤1.5 mm can already be sufficient. However, to ensure analytical results with relative standard deviations of less than 20%, as recommended by the EN 62321, a much larger effort for sample processing towards smaller particle sizes might be required which strongly depends on the mass fraction of the element under investigation.

  2. A Method for Automatic Inspection of Printed Circuit Boards by Using the Thermal Signature

    International Nuclear Information System (INIS)

    This paper aims to design a system for automating inspection of the printed circuit boards (PCBs) by using the thermal signature of the different integrated circuits (I.C). The proposed inspection system consists of the inspection circuit, data acquisition system (DAS) and personal computer. Inspection is done by comparing the thermal signature of normally operated circuit with the thermal signature of circuit under test. One thermistor is assigned to each component in the circuit. The thermistor must touch tightly the surface of the I.C. to sense its temperature during the inspection process. Matlab software is used to represent the thermal signature through different colors. The Turbo C software is used to develop a program for acquiring and comparing the thermal signature of the circuit under the test with the reference circuit. If the colors of the two thermal signatures for the same I.C. are same then the circuit under test is fault free and does not contain any defect. On the other side, if the colors of the two thermal signatures for the same I.C. are different then the circuit under test is defective

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

    International Nuclear Information System (INIS)

    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

  4. WASTE PRINTED CIRCUIT BOARDS SEPARATION IN ELECTROSTATIC SEPARATOR

    Directory of Open Access Journals (Sweden)

    Branimir Fuk

    2012-12-01

    Full Text Available Printed circuit boards from electronic waste are very important source of precious metals by recycling. The biggest challenge is liberation and separation of useful components; thin film which contains copper, zinc, tin, lead and precious metals like silver, gold and palladium from non useful components; polymers, ceramics and glass fibbers. The paper presents results for separation of shredded printed circuit boards from TV sets in electrostatic separator. Testing where conducted with material class 2/1 and 1/0.5 mm in laboratory on equipment for mineral processing. Results showed influence from independent variable; separation knife gradient, drum rotation speed and voltage on concentrate quality and recovery (the paper is published in Croatian.

  5. Printed Circuit Board Integrated Toroidal Radio Frequency Inductors

    DEFF Research Database (Denmark)

    Kamby, Peter; Knott, Arnold; Andersen, Michael A. E.

    2012-01-01

    implemented as solenoids, either in spiral or cylindrical form. Those have the disadvantage of excessive stray fields, which can cause losses and disturbances in adjacent circuitry. Therefore this paper presents the analysis, design and realization of a printed circuit board (PCB) integrated inductor under...... significant consideration of the losses in the inductor. The analysis results in a general design tool which is verified by a prototype inductor. Its inductance is 50 nH and has a quality of 149 at 100 MHz....

  6. DC Arc Plasma Disposal of Printed Circuit Board

    Institute of Scientific and Technical Information of China (English)

    黄建军; 施嘉标; 孟月东; 刘正之

    2004-01-01

    A new solid waste disposal technology setup with DC arc plasma is presented. Being different from conventional combustion or burning such as incineration, it is based on a process called controlled high-temperature pyrolysis, the thermal destruction and recovery process. The results of vitrification of the circuit board is presented. The properties of vitrified product including hardness and leaching test results are presented. The final product (vitrified material) and air emission from the plasma treatment is environmentally acceptable.

  7. DC arc plasma disposal of printed circuit board

    International Nuclear Information System (INIS)

    A new solid waste disposal technology setup with DC arc plasma is presented. Being different from conventional combustion or burning such as incineration, it is based on a process called controlled high-temperature pyrolysis, the thermal destruction and recovery process. The results of vitrification of the circuit board are presented. The properties of vitrified product including hardness and leaching test results are presented. The final product (vitrified material) and air emission from the plasma treatment is environmentally acceptable. (authors)

  8. Ruggedizing Printed Circuit Boards Using a Wideband Dynamic Absorber

    Directory of Open Access Journals (Sweden)

    V.C. Ho

    2003-01-01

    Full Text Available The existing approaches to ruggedizing inherently fragile and sensitive critical components of electronic equipment such as printed circuit boards (PCB for use in hostile industrial and military environment are either insufficient or expensive. This paper addresses a novel approach towards ruggedizing commercial-off-the-shelf PCBs using a miniature wideband dynamic absorber. The optimisation technique used relies on the experimentally measured vibration spectra and complex receptance of the original PCB.

  9. A Novel Technique to Perform Plating on Printed Circuit Board

    Directory of Open Access Journals (Sweden)

    S. Jayapoorani

    2011-01-01

    Full Text Available Problem statement: This research attempts to optimize the parameters for pulse plating of silver on printed circuit board. The idea here is to use pulse plating technique which is metal deposition by pulsed electrolysis method. Approach: Printed Circuit Boards (PCB plays a major role in all communication and electronics industry. Silver is a ductile and malleable metal which has 7% higher conductivity than copper. Here the electro deposit is influenced by current density, silver concentration in the bath, applied current type. Pulse plating technique is used in double sided printed circuit board especially in the case of plated through hole technique. Here exist a necessity to do plating which will deposit a metal wall in the substrate and it will connect between the components. Results: This method of pulse plating proves that it avoids the disadvantage of rough deposition that is caused due to DC plating in PCB's. Conclusion: The surface morphology and the grain size is measured using XRD analysis and it proves that the number of pin holes is reduced.

  10. Computational Aspects of Feedback in Neural Circuits

    OpenAIRE

    Wolfgang Maass; Prashant Joshi; Sontag, Eduardo D.

    2007-01-01

    It has previously been shown that generic cortical microcircuit models can perform complex real-time computations on continuous input streams, provided that these computations can be carried out with a rapidly fading memory. We investigate the computational capability of such circuits in the more realistic case where not only readout neurons, but in addition a few neurons within the circuit, have been trained for specific tasks. This is essentially equivalent to the case where the output of t...

  11. Analog Computation by DNA Strand Displacement Circuits.

    Science.gov (United States)

    Song, Tianqi; Garg, Sudhanshu; Mokhtar, Reem; Bui, Hieu; Reif, John

    2016-08-19

    DNA circuits have been widely used to develop biological computing devices because of their high programmability and versatility. Here, we propose an architecture for the systematic construction of DNA circuits for analog computation based on DNA strand displacement. The elementary gates in our architecture include addition, subtraction, and multiplication gates. The input and output of these gates are analog, which means that they are directly represented by the concentrations of the input and output DNA strands, respectively, without requiring a threshold for converting to Boolean signals. We provide detailed domain designs and kinetic simulations of the gates to demonstrate their expected performance. On the basis of these gates, we describe how DNA circuits to compute polynomial functions of inputs can be built. Using Taylor Series and Newton Iteration methods, functions beyond the scope of polynomials can also be computed by DNA circuits built upon our architecture. PMID:27363950

  12. A tool for errors detection in printed circuit boards production

    Directory of Open Access Journals (Sweden)

    A. de Luca Pennacchia

    2009-04-01

    Full Text Available The progressive implementation of software functions in Integrated Circuits (ICs has considerably increased the number oftransistors and pin connections of ICs. For that reason, Printed Circuit Boards (PCBs are fabricated with the Surface MountTechnology (SMT nowadays and IC mounting on PCB is a crucial process that requires high precision. An Automatic MechanicalMontage (AMM system is used to mount ICs on the sockets using a couple of reference points for every IC in order to find thecorrect positions for mounting the IC. Due to some factors in the process of PCB development, there are differences betweendesigned and manufactured PCBs, which could generate delays in their production. In this work, a software tool which allows towork with digital images of PCBs is described. This tool finds the differences generated in PCB development, especially thedifferences in IC reference points using Digital Image Processing (DIP techniques.

  13. Leaching studies for metals recovery from printed circuit boards scrap

    OpenAIRE

    Oliveira, Paula C.; Cabral, Marta; Taborda, F. Charters; Margarido, F.; Nogueira, C. A.

    2009-01-01

    In this paper, the leaching behavior of the major metals present in printed circuit boards waste is evaluated, aiming at its recycling by hydrometallurgy. Several leachants were compared (sulfuric, hydrochloric and nitric acids, at 2 M H+ concentration), at temperatures of 25ºC and 90ºC and 4 hours of reaction time. Sulfuric acid leaching was not very promising concerning metals dissolution being only effective for iron. Hydrochloric acid allowed the leaching up to 60% of tin and about 50% of...

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

    Science.gov (United States)

    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.

  15. Ion chromatography in the manufacture of multilayer circuit boards

    Science.gov (United States)

    Smith, Robert E.

    1990-01-01

    Ion chromatography (IC) has proven useful in analyzing chemical solutions used in the manufacture of multilayer circuit boards. Unlike other chemical quantification techniques, IC provides results on ions not expected in the production solutions. Thus, solution contamination and break-down products can be monitored in every phase of the circuit board manufacturing. During the first phase, epoxy laminates experience an etchback, first in chromic acid, which can be analyzed for trace chloride and sulfate, then in ammonium bifluoride/HCl, which can be analyzed for fluoride and chloride. Following a wet-blasting to roughen up the surface, 20 microinches of copper are deposited using an electroless bath. Again, IC is applicable for monitoring formate, tartarate, and sulfate levels. Next, an acid copper bath is used to electroplate the through holes with 0.001 inches of ductile copper. This bath is analyzed for trace chloride. Photoimaging is then performed, and the organic solvents used can be assayed for trace ionic chloride. Finally, a fluoroboric acid-based tin-lead bath is used to deposit a solderable alloy. This bath is analyzed for fluoroborate, tin, and lead. In addition, mobile phase ion chromatography (MPIC) is used to monitor the nonionic organic brighteners in the baths.

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

    Science.gov (United States)

    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.

  17. Sliding contacts on printed circuit boards and wear behavior

    Science.gov (United States)

    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.

  18. Size distribution of wet crushed waste printed circuit boards

    Institute of Scientific and Technical Information of China (English)

    Tan Zhihai; He Yaqun; Xie Weining; Duan Chenlong; Zhou Enhui; Yu Zheng

    2011-01-01

    A wet impact crusher was used to breakdown waste printed circuit boards (PCB's) in a water medium.The relationship between the yield of crushed product and the operating parameters was established.The crushing mechanism was analyzed and the effects of hammerhead style,rotation speed,and inlet water volume on particle size distribution were investigated.The results show that the highest yield of -1 + 0.75 mm sized product was obtained with an inlet water volume flow rate of 5.97 m3/h and a smooth hammerhead turning at 1246.15 r/min.Cumulative undersize-product yield curves were fitted to a nonlinear function:the fitting correlation coefficient was greater than 0.998.These research results provide a theoretical basis for the highly effective wet crushing of PCB's.

  19. Research on Selective Shredding of Wasted Printed Circuit Boards

    Institute of Scientific and Technical Information of China (English)

    曹亦俊; 文学峰; 赵跃民

    2002-01-01

    Electronic scrap, especially wasted printed circuit boards (PCBs), is regarded as an environmental challenge. At present, the physical separation is thought to be the environmental friendly and economical method of treating and reutilizing electronic waste. An effective liberation of metals from non-metallic components is a crucial step towards mechanical separation and recycling of wasted PCBs. In this paper, the selective shredding theory and mechanics characteristics of wasted PCBs were analyzed, and the shredded experiments of wasted PCBs by hammer mill were investigated. The result shows that the selective shredding exists in the wasted PCBs shredded process by hammer mill. The shredding velocity of non-metallic components is far greater than that of metals in the wasted PCBs shredding, which makes the metals concentrate in the coarser fraction. And the impact force of hammer mill is superior to metal liberation from non-metallic components, a satisfied metal liberation degree can be achieved in the wasted PCBs shredding by hammer mill.

  20. Ion chromatography in the manufacture of multilayer circuit boards

    Science.gov (United States)

    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.

  1. Crushing performance and resource characteristic of printed circuit board scrap

    Institute of Scientific and Technical Information of China (English)

    WANG Hui; GU Guo-hua; QI Yun-feng

    2005-01-01

    The crushing performance of printed circuit board (PCB) was studied on several crushers. The results show that PCB is a material which is difficult to crush. The crushing performance of PCB with disk crusher, especially vibration grinding, which has cut or impact action, excels that of jaw crusher or roller crusher. The PCB scrap is worthwhile to recycle using variety of modern characterization methods. When compared with natural resources, this material stream remains a rich precious metal and nonferrous metals. In PCB scrap, metals account for 47% of the total material composition, in which there exists 19.66% copper, 11.47% iron, 3.93% lead, 300 g/t gold and 5-10 kg/t silver, etc. In addition, the PCB scrap contains 27% of plastics and 26% of refractory oxides.

  2. A corrected method of distorted printed circuit board image

    Institute of Scientific and Technical Information of China (English)

    Qiao Nao-Sheng; Ye Yu-Tang; Huang Yong-Lin

    2011-01-01

    This paper proposes a corrected method of distorted image based on adaptive control. First, the adaptive control relationship of pixel point positions between distorted image and its corrected image is given by using polynomial fitting,thus control point pairs between the distorted image and its corrected image are found. Secondly, the value of both image distortion centre and polynomial coefficient is obtained with least square method, thus the relationship of each control point pairs is deduced. In the course of distortion image processing, the gray value of the corrected image is changed into integer with bilinear interpolation. Finally, the experiments are performed to correct two distorted printed circuit board images. The results are perfect and the mean square errors of residual error are tiny.

  3. Radiological characterization of printed circuit boards for future elimination.

    Science.gov (United States)

    Zaffora, Biagio; Magistris, Matteo

    2016-07-01

    Electronic components like printed circuit boards (PCBs) are commonly used in CERN's accelerator complex. During their lifetime some of these PCBs are exposed to a radiation field of protons, neutrons and pions and are activated. In view of their disposal towards the appropriate final repository, a radiological characterization must be performed. The present work proposes a general characterization procedure based on the definition of a reference chemical composition, on the calculation of the corresponding radionuclide inventory and on the measurement of a tracer radionuclide. This method has been validated with real-life cases of electronic boards which were exposed to the typical radiation fields in CERN's accelerators. The activation studies demonstrate that silver is the key element with respect to the radiological characterization of electronic waste due to the production of Ag-110m and Ag-108m. A sensitivity analysis shows that the waiting time is the main parameter affecting the radionuclide inventory. Results also indicate that, as is the case of other families of radioactive waste, an accurate assessment of the radiological inventory of PCBs would require the precise knowledge of their chemical composition, as well as the radiation field to which they were exposed. PMID:27129133

  4. FORMATION OF A COMPUTER SECURITY POLICY BOARD

    CERN Multimedia

    2001-01-01

    In view of the increasing number of security incidents at CERN, the Directorate has set up a Computer Security Policy Board. Information about the mandate and the meetings of the Board is linked from http://cern.ch/security, which is the entry point for computer security information at CERN. FILE SERVICES COMPUTING RULE The use of CERN's Computing facilities are governed by Operational Circular No 5 and its subsidiary rules. To protect file servers at CERN from unauthorised use, the Organization has issued a new subsidiary rule related to file services. Details hereof and of the complete set of rules applicable to the use of CERN computing facilities are available at http://cern.ch/ComputingRules.

  5. FORMATION OF A COMPUTER SECURITY POLICY BOARD

    CERN Multimedia

    2001-01-01

    In view of the increasing number of security incidents at CERN, the Directorate has set up a Computer Security Policy Board. Information about the mandate and the meetings of the Board is linked from http://cern.ch/security which is the entry point for computer security information at CERN. File Services Computing Rule The use of CERN's Computing facilities are governed by Operational Circular No 5 and its subsidiary rules. To protect file servers at CERN from unauthorised use, the Organization has issued a new subsidiary rule related to file services. Details hereof and of the complete set of rules applicable to the use of CERN computing facilities are available at http://cern.ch/ComputingRules

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

    Science.gov (United States)

    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. Staged circuit switching for network computers

    Energy Technology Data Exchange (ETDEWEB)

    Arango, M.; Gelernter, D.; Badr, H.; Bernstein, A.J.

    1983-03-01

    Staged cricuit switching (SCS) is a message-switching technique which combines a new protocol with new communication hardware. Protocol and hardware are designed specifically for networks which are intended to function as integrated, general-purpose MIMD machines, i.e. for network computers. The SCS protocol is a form of circuit switching which degrades automatically into packet switching when unavailable output lines make further extension of a partial circuit impossible. The SCS hardware uses a front-end crossbar switch to multiplex some small number of communication channels among all of a given node's incident links. Together, hardware and protocol represent an attempt to convert spare bandwidth into lower network delays. They also allow experimentation with networks which reconfigure themselves dynamically in response to measured traffic patterns. SCS is compared with packet switching, circuit switching and the virtual cut-through protocol of P. Kermani and L.Kleinrock (see Comput. Networks, vol.3, p.267, 1979, and IEEE Trans. Comput. C-29,12, p.1052, December 1980), and an SCS implementation designed for the SBN network computer is discussed. 23 references.

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

    Science.gov (United States)

    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

  9. Waste minimization assessment for a printed-circuit-board manufacturer. Environmental research brief

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-05-01

    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 the University of Tennessee performed an assessment at a plant manufacturing printed circuit boards for television sets--approximately 4.3 million sq ft of finished boards per yr. To make printed circuit boards, the plant begins with making screens as all printing is accomplished using silk-screening techniques. The circuit boards undergo several operations including punching, scrubbing, printing, etching, and soldering. The team's report, detailing findings and recommendations, indicated that the majority of waste was generated in the circuit board production lines but the greatest savings could be obtained by installing a closed-loop cooling water system to reduce (60%) excess water usage in the UV-light curing ovens after screen printing and the cooling of the cupric chloride etch tanks.

  10. A study of liberation and separation process of metals from printed circuit boards (PCBs) scrap

    International Nuclear Information System (INIS)

    Since the metallic elements are covered with or encapsulated by various plastic or ceramic materials on printed circuit boards, a mechanical pre-treatment process allowing their liberation and separation is first needed in order to facilitate their efficient extraction with hydrometallurgy route. Even though many studies have been performed on the mechanical pre-treatment processing for the liberation and separation of the metallic components of printed circuit boards scrap, further studies are required to pave the way for efficient recycling of waste printed circuit boards through a combination of mechanical pre-treatment and hydrometallurgical technology. In this work, a fundamental study has been carried out on the mechanical pre-treatment that is necessary to recover metallic concentrates from printed circuit boards scraps. The most important problem is to separate or release particles from the associated gangue minerals at the possible liberation particle size. The distribution of metallic elements has been also investigated in relation to the particle size of the milled printed circuit boards. The samples of printed circuit boards were separated into the magnetic and non-magnetic fractions by Rare-earth Roll Magnetic separator. Thereafter, the magnetic and non-magnetic fractions were separated to heavy fraction (metallic elements) and light fraction (plastic) by Mozley Laboratory Table Separator. The recovery ratios and the evaluation of the metallic concentrates recovered by each separation process were also investigated. This study is expected to provide useful data for the efficient mechanical separation of metallic components from printed circuit boards scraps. (author)

  11. Waste printed circuit board recycling techniques and product utilization

    Energy Technology Data Exchange (ETDEWEB)

    Hadi, Pejman; Xu, Meng [Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong Special Administrative Region (Hong Kong); Lin, Carol S.K. [School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region (Hong Kong); Hui, Chi-Wai [Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong Special Administrative Region (Hong Kong); McKay, Gordon, E-mail: kemckayg@ust.hk [Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong Special Administrative Region (Hong Kong); Division of Sustainable Development, College of Science, Engineering and Technology, Hamad Bin Khalifa University, Qatar Foundation, Doha (Qatar)

    2015-02-11

    Highlights: • There is a major environmental issue about the printed circuit boards throughout the world. • Different physical and chemical recycling techniques have been reviewed. • Nonmetallic fraction of PCBs is the unwanted face of this waste stream. • Several applications of the nonmetallic fraction of waste PCBs have been introduced. - Abstract: 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.

  12. Waste printed circuit board recycling techniques and product utilization

    International Nuclear Information System (INIS)

    Highlights: • There is a major environmental issue about the printed circuit boards throughout the world. • Different physical and chemical recycling techniques have been reviewed. • Nonmetallic fraction of PCBs is the unwanted face of this waste stream. • Several applications of the nonmetallic fraction of waste PCBs have been introduced. - Abstract: 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

  13. International standards for optical circuit board fabrication, assembly and measurement

    Science.gov (United States)

    Pitwon, Richard; Immonen, Marika; Wang, Kai; Itoh, Hideo; Shioda, Tsuyoshi; Wu, Jinhua; Zhu, Long Xiu; Yan, Hui Juan; Worrall, Alex

    2016-03-01

    The commercial adoption of electro-optical printed circuit board (EOCB) technology will be accelerated by the development of industrial and conformity standards for high volume fabrication, connector assembly and waveguide measurement. In this paper, we introduce international standardisation activities surrounding EOCBs and report on industrial processes developed for the high volume fabrication of complex EOCBs with embedded multimode polymer waveguides including a first connector standard for polymer waveguide termination. We focus on solving a serious historic problem with the measurement of optical waveguide systems, namely the lack of harmonised measurement conditions for optical waveguides, which to this day gives rise to strong inconsistencies in the results of measurements by different parties on the same waveguide. We report on the development of a standard to ensure repeatable measurement of optical waveguides, whereby we demonstrate how the application of a measurement identification system and proposed reference measurement conditions can bring variation in measurement results to within 5%, thereby serving as the basis for a formal reliable optical waveguide measurement methodology.

  14. Recovery of high purity precious metals from printed circuit boards

    International Nuclear Information System (INIS)

    Waste printed circuit boards (WPCB) have an inherent value because of the precious metal content. For an effective recycling of WPCB, it is essential to recover the precious metals. This paper reports a promising method to recover the precious metals. Aqua regia was used as a leachant and the ratio between metals and leachant was fixed at 1/20 (g/ml). Silver is relatively stable so the amount of about 98 wt.% of the input was recovered without an additional treatment. Palladium formed a red precipitate during dissolution, which were consisted of Pd(NH4)2Cl6. The amount precipitated was 93 wt.% of the input palladium. A liquid-liquid extraction with toluene was used to extract gold selectively. Also, dodecanethiol and sodium borohydride solution were added to make gold nanoparticles. Gold of about 97 wt.% of the input was recovered as nanoparticles which was identified with a high-resolution transmission electron microscopy through selected area electron diffraction and nearest-neighbor lattice spacing.

  15. PHYSICAL CHEMISTRY CHARACTERIZATION OF PRINTED CIRCUIT BOARD OF MOBILE PHONES

    Directory of Open Access Journals (Sweden)

    Hellington Bastos da Silva de Sant’ana

    2015-07-01

    Full Text Available Nowadays, electronics industry is the leading sector in developing new technologies. These new technologies lead to cheaper products increasing the consumption. The lifetime of such products is relatively short and soon it becomes waste, known as electronic waste. Cell phone is a common electronic waste. This waste represents an interesting raw material, because it contains large amount of base metals, considerable amount of valuable metals and also those dangerous. In this work, the electronic waste was submitted to mechanical processing: initially the devices were separated into two categories, as year of release (2002 and disassembled manually. The printed circuit boards were milled below 1 mm and then submitted to density and magnetic separation processes. The fractions obtained during the mechanical processing were characterized by chemical analysis. Using mechanical processing it was possible to obtain metal fractions of 80 wt%. A leaching test was carried out to determine if a waste needs to be managed as a hazardous; so that, cell phone waste must be considered in the category of hazardous residue because the lead concentration was above the limit established by Brazilian Standards

  16. 29 CFR 1915.181 - Electrical circuits and distribution boards.

    Science.gov (United States)

    2010-07-01

    ... employee is permitted to work on an electrical circuit, except when the circuit must remain energized for testing and adjusting, the circuit shall be deenergized and checked at the point at which the work is to be done to insure that it is actually deenergized. When testing or adjusting an energized circuit...

  17. Nonlinear optics quantum computing with circuit QED.

    Science.gov (United States)

    Adhikari, Prabin; Hafezi, Mohammad; Taylor, J M

    2013-02-01

    One approach to quantum information processing is to use photons as quantum bits and rely on linear optical elements for most operations. However, some optical nonlinearity is necessary to enable universal quantum computing. Here, we suggest a circuit-QED approach to nonlinear optics quantum computing in the microwave regime, including a deterministic two-photon phase gate. Our specific example uses a hybrid quantum system comprising a LC resonator coupled to a superconducting flux qubit to implement a nonlinear coupling. Compared to the self-Kerr nonlinearity, we find that our approach has improved tolerance to noise in the qubit while maintaining fast operation.

  18. A 5 Giga Samples Per Second 8-Bit Analog to Digital Printed Circuit Board for Radio Astronomy

    Science.gov (United States)

    Jiang, Homin; Liu, Howard; Guzzino, Kim; Kubo, Derek; Li, Chao-Te; Chang, Ray; Chen, Ming-Tang

    2014-08-01

    We have designed, manufactured, and characterized an 8-bit 5 Giga samples per second (Gsps) ADC printed circuit board assembly (PCBA). An e2v EV8AQ160 ADC chip was used in the design and the board is plug compatible with the field programmable gate array (FPGA) board developed by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER) community. Astronomical interference fringes were demonstrated across a single baseline pair of antennas using two ADC boards on the Yuan Tseh Lee Array for Microwave Background Anisotropy (AMiBA) telescope. Several radio interferometers are using this board for bandwidth expansion, such as Submillimeter Array; also, several experimental telescopes are building new spectrometers using the same board. The ADC boards were attached directly to the Reconfigurable Open Architecture Computing Hardware (ROACH-2) FPGA board for processing of the digital output signals. This ADC board provides the capability of digitizing radio frequency signals from DC to 2 GHz (3 dB bandwidth), and to an extended bandwidth of 2.5 GHz (5 dB) with derated performance. The following worst-case performance parameters were obtained over 2 GHz: spur free dynamic range (SFDR) of 44 dB, signal-to-noise and distortion (SINAD) of 35 dB, and effective number of bits (ENOB) of 5.5.

  19. Polyimide Nanocomposite Circuit Board Materials to Mitigate Internal Electrostatic Discharge Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In Sub-topic T8.02, NASA has identified a need for improved circuit boards to mitigate the hazards of internal electrostatic discharge (IESD) on missions where high...

  20. Shielding properties of conductive plastic housings loaded with printed circuit boards

    OpenAIRE

    Lozano Guerrero, Antonio José; Robinson, Martin Paul; Díaz Morcillo, Alejandro Benedicto; Monzó Cabrera, Juan; Clemente Fernández, Francisco Javier; Balbastre Tejedor, Juan Vicente

    2012-01-01

    In this paper the benefits of using conductive plastics in enclosure configurations have been evaluated taking into account the influence of internal printed circuit boards. Conductive plastic enclosures are a very attractive alternative to traditional metallic enclosures to protect electronic systems against electromagnetic interference. A wide range of conductivities can be obtained with these materials to satisfy a required design. An equivalent model for the printed circuit board has b...

  1. Research on Toxicity Evaluation of Waste Incineration Residues of Printed Circuit Boards

    OpenAIRE

    Rasa Volungevičienė; Violeta Bolutienė; Kęstutis Buinevičius

    2014-01-01

    Recycling waste printed circuit boards (PCB) is an extremely complicated process, because PCBs consist of a number of complex components – hazardous and non-hazardous materials sets. Pyrolysis and combustion are currently the most effective treatment technologies for waste printed circuit boards. Pyrolysis can be used for thermally decomposing PCBs allowing for the simultaneous recovery of valuable materials. Following the extraction of valuable materials, the problem of residual ash utilizat...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  4. Newnes circuit calculations pocket book with computer programs

    CERN Document Server

    Davies, Thomas J

    2013-01-01

    Newnes Circuit Calculations Pocket Book: With Computer Programs presents equations, examples, and problems in circuit calculations. The text includes 300 computer programs that help solve the problems presented. The book is comprised of 20 chapters that tackle different aspects of circuit calculation. The coverage of the text includes dc voltage, dc circuits, and network theorems. The book also covers oscillators, phasors, and transformers. The text will be useful to electrical engineers and other professionals whose work involves electronic circuitry.

  5. Challenging the evolutionary strategy for synthesis of analogue computational circuits

    OpenAIRE

    Sapargaliyev, YA; Kalganova, TG

    2010-01-01

    There are very few reports in the past on applications of Evolutionary Strategy (ES) towards the synthesis of analogue circuits. Moreover, even fewer reports are on the synthesis of computational circuits. Last fact is mainly due to the dif-ficulty in designing of the complex nonlinear functions that these circuits perform. In this paper, the evolving power of the ES is challenged to design four computational circuits: cube root, cubing, square root and squaring functions. The synthesis succe...

  6. [Computer Science and Telecommunications Board activities

    Energy Technology Data Exchange (ETDEWEB)

    Blumenthal, M.S.

    1993-02-23

    The board considers technical and policy issues pertaining to computer science, telecommunications, and associated technologies. Functions include providing a base of expertise for these fields in NRC, monitoring and promoting health of these fields, initiating studies of these fields as critical resources and sources of national economic strength, responding to requests for advice, and fostering interaction among the technologies and the other pure and applied science and technology. This document describes its major accomplishments, current programs, other sponsored activities, cooperative ventures, and plans and prospects.

  7. Memristor-based nanoelectronic computing circuits and architectures

    CERN Document Server

    Vourkas, Ioannis

    2016-01-01

    This book considers the design and development of nanoelectronic computing circuits, systems and architectures focusing particularly on memristors, which represent one of today’s latest technology breakthroughs in nanoelectronics. The book studies, explores, and addresses the related challenges and proposes solutions for the smooth transition from conventional circuit technologies to emerging computing memristive nanotechnologies. Its content spans from fundamental device modeling to emerging storage system architectures and novel circuit design methodologies, targeting advanced non-conventional analog/digital massively parallel computational structures. Several new results on memristor modeling, memristive interconnections, logic circuit design, memory circuit architectures, computer arithmetic systems, simulation software tools, and applications of memristors in computing are presented. High-density memristive data storage combined with memristive circuit-design paradigms and computational tools applied t...

  8. Synthetic analog and digital circuits for cellular computation and memory

    OpenAIRE

    Purcell, Oliver; Lu, Timothy K.

    2014-01-01

    Biological computation is a major area of focus in synthetic biology because it has the potential to enable a wide range of applications. Synthetic biologists have applied engineering concepts to biological systems in order to construct progressively more complex gene circuits capable of processing information in living cells. Here, we review the current state of computational genetic circuits and describe artificial gene circuits that perform digital and analog computation. We then discuss r...

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

    Energy Technology Data Exchange (ETDEWEB)

    Min, Li; Huang, Lirong, E-mail: lrhuang@hust.edu.cn [Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    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.

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

    International Nuclear Information System (INIS)

    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

  11. Leakage-Resilient Circuits without Computational Assumptions

    DEFF Research Database (Denmark)

    Dziembowski, Stefan; Faust, Sebastian

    2012-01-01

    Physical cryptographic devices inadvertently leak information through numerous side-channels. Such leakage is exploited by so-called side-channel attacks, which often allow for a complete security breache. A recent trend in cryptography is to propose formal models to incorporate leakage into the ......Physical cryptographic devices inadvertently leak information through numerous side-channels. Such leakage is exploited by so-called side-channel attacks, which often allow for a complete security breache. A recent trend in cryptography is to propose formal models to incorporate leakage......: (i) in each observation the leakage is bounded, (ii) different parts of the computation leak independently, and (iii) the randomness that is used for certain operations comes from a simple (non-uniform) distribution. In contrast to earlier work on leakage resilient circuit compilers, which relied...... on computational assumptions, our results are purely information-theoretic. In particular, we do not make use of public key encryption, which was required in all previous works...

  12. PUZZLE - A program for computer-aided design of printed circuit artwork

    Science.gov (United States)

    Harrell, D. A. W.; Zane, R.

    1971-01-01

    Program assists in solving spacing problems encountered in printed circuit /PC/ design. It is intended to have maximum use for two-sided PC boards carrying integrated circuits, and also aids design of discrete component circuits.

  13. Printed Circuit Board Embedded Inductors for Very High Frequency Switch-Mode Power Supplies

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.;

    2013-01-01

    The paper describes the design of three different structures for printed circuit board embedded inductors. Direct comparison of spirals, solenoids and toroids are made with regard to inductance, dc and ac resistance, electromagnetic field and design flexibility. First the equations for the impeda......The paper describes the design of three different structures for printed circuit board embedded inductors. Direct comparison of spirals, solenoids and toroids are made with regard to inductance, dc and ac resistance, electromagnetic field and design flexibility. First the equations...

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

    Science.gov (United States)

    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.

  15. Printed circuit board for a CCD camera head

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

    Science.gov (United States)

    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. Reduction of crosstalk on printed circuit board using genetic algorithm in switching power supply

    OpenAIRE

    Pong, MH; Wu, X; Lee, CM; Qian, Z.

    2001-01-01

    Crosstalk between printed circuit board (PCB) traces in switching power supplies may cause high electromagnetic interference emission. PCB layout plays an important part and a genetic algorithm (GA) is used to produce a layout with reduced crosstalk. A coupling index and a new way of representing a trace for the GA process is presented.

  19. Investigation, development and verification of printed circuit board embedded air-core solenoid transformers

    DEFF Research Database (Denmark)

    Mønster, Jakob Døllner; Madsen, Mickey Pierre; Pedersen, Jeppe Arnsdorf;

    2015-01-01

    A new printed circuit board embedded air-core transformer/coupled inductor is proposed and presented. The transformer is intended for use in power converter applications operating at very high frequency between 30 MHz to 300 MHz. The transformer is based on two or more solenoid structures...

  20. Radiation evaluation method of commercial off-the-shelf (COTS) electronic printed circuit boards (PCBs)

    International Nuclear Information System (INIS)

    We present a radiation evaluation methodology and proton ground test results for candidate COTS PCBs (commercial off-the-shelf electronic printed circuit boards) and their associated electronics for low-altitude, low-inclination orbits. We will also discuss the implications associated with mission orbit and duration. (authors)

  1. Non-unitary probabilistic quantum computing circuit and method

    Science.gov (United States)

    Williams, Colin P. (Inventor); Gingrich, Robert M. (Inventor)

    2009-01-01

    A quantum circuit performing quantum computation in a quantum computer. A chosen transformation of an initial n-qubit state is probabilistically obtained. The circuit comprises a unitary quantum operator obtained from a non-unitary quantum operator, operating on an n-qubit state and an ancilla state. When operation on the ancilla state provides a success condition, computation is stopped. When operation on the ancilla state provides a failure condition, computation is performed again on the ancilla state and the n-qubit state obtained in the previous computation, until a success condition is obtained.

  2. Effects of Temperature on the Wave Soldering of Printed Circuit Boards: CFD Modeling Approach

    Directory of Open Access Journals (Sweden)

    M.S. Abdul Aziz

    2016-01-01

    Full Text Available ABSTRACT This study investigated the effects of temperature on the wave soldering of printed circuit boards (PCBs using three-dimensional finite volume analysis. A computational solder pot model consisting of a six-blade rotational propeller was developed and meshed using tetrahedral elements. The leaded molten solder (Sn63Pb37 distribution and PCB wetting profile were determined using the volume of fluid technique in the fluid flow solver, FLUENT. In this study, the effects of five different molten solder temperatures (456 K, 473 K, 523 K, 583 K, and 643 K on the wave soldering of a 70 mm × 146 mm PCB were considered. The effects of temperature on wetting area, wetting profile, velocity vector, and full wetting time were likewise investigated. Molten solder temperature significantly affected the wetting time and distribution of PCBs. The molten solder temperature at 523 K demonstrated desirable wetting distribution and yielded a stable fountain profile and was therefore considered the best temperature in this study. The simulation results were substantiated by the experimental results.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. PMID:27067430

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

    International Nuclear Information System (INIS)

    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 5.0 mm. The fractions of milled printed circuit boards of size 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

  6. Water-Based Coating Simplifies Circuit Board Manufacturing

    Science.gov (United States)

    2008-01-01

    The Structures and Materials Division at Glenn Research Center is devoted to developing advanced, high-temperature materials and processes for future aerospace propulsion and power generation systems. The Polymers Branch falls under this division, and it is involved in the development of high-performance materials, including polymers for high-temperature polymer matrix composites; nanocomposites for both high- and low-temperature applications; durable aerogels; purification and functionalization of carbon nanotubes and their use in composites; computational modeling of materials and biological systems and processes; and developing polymer-derived molecular sensors. Essentially, this branch creates high-performance materials to reduce the weight and boost performance of components for space missions and aircraft engine components. Under the leadership of chemical engineer, Dr. Michael Meador, the Polymers Branch boasts world-class laboratories, composite manufacturing facilities, testing stations, and some of the best scientists in the field.

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

    OpenAIRE

    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 ...

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Jakub Szałatkiewicz

    2016-08-01

    Full Text Available 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.

  10. Research on Toxicity Evaluation of Waste Incineration Residues of Printed Circuit Boards

    Directory of Open Access Journals (Sweden)

    Rasa Volungevičienė

    2014-10-01

    Full Text Available Recycling waste printed circuit boards (PCB is an extremely complicated process, because PCBs consist of a number of complex components – hazardous and non-hazardous materials sets. Pyrolysis and combustion are currently the most effective treatment technologies for waste printed circuit boards. Pyrolysis can be used for thermally decomposing PCBs allowing for the simultaneous recovery of valuable materials. Following the extraction of valuable materials, the problem of residual ash utilization is encountered. Determining the qualitative and quantitative characteristics of incineration residue helps with choosing effective ash management technologies. This paper analyzes PCB ash generated at three different temperatures of 400 °C, 500 °C and 600 °C. Ash residues have been analysed to determine the quantity and type of metals present. Furthermore, the experiment of leaching heavy metals from ash has been described.

  11. Evaluation of building technology for mass producible millimetre-sized robots using flexible printed circuit boards

    International Nuclear Information System (INIS)

    Initial tests of a building technology for a compact three-dimensional mass producible microrobot are presented. The 3.9 × 3.9 × 3.3 mm3 sized prototype robot represents a microsystem with actuators, sensors, energy management and integrated electronics. The weight of a folded robot is 65 mg and the total volume is less than 23 mm3. The design of the interfaces of the different modules in the robot, as well as the building technology, is described. The modules are assembled using conductive adhesive with industrial surface mounting technology on a thin double-sided flexible printed circuit board. The final shape of the microrobots is achieved by folding the flexible printed circuit board twice. Electrical and mechanical studies are performed to evaluate the assembly and it is concluded that the technology can be used for this type of microsystem. Several issues using the presented assembly technique are identified and addressed

  12. Catalytic Pyrolysis and a Pyrolysis Kinetic Study of Shredded Printed Circuit Board for Fuel Recovery

    OpenAIRE

    Salmiaton Ali; Chee Hoe Ng; Hizam Hashim

    2014-01-01

    Scrap printed circuit boards (PCBs) are the most abundant wastes that can be found in the landfills in Malaysia and this disposal certainly poses serious detrimental to the environment. This research aims to investigate optimum temperature for pyrolyzing waste PCBs, find out the best catalyst to be used in accelerating PCBs’ pyrolysis, select suitable ratio of catalyst to PCBs for higher oil yield and examine kinetics pyrolysis of the waste PCBs’ decomposition. Operating temperatures ranged f...

  13. Search for the optimal size of printed circuit boards for mechanical structures for electronic equipment

    Directory of Open Access Journals (Sweden)

    Yefimenko A. A.

    2014-12-01

    Full Text Available The authors present a method, an algorithm and a program, designed to determine the optimal size of printed circuit boards (PCB of mechanical structures and different kinds of electronic equipment. The PCB filling factor is taken as an optimization criterion. The method allows one to quickly determine the dependence of the filling factor on the size of the PCB for various components.

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

    OpenAIRE

    Ruan Jujun; Zheng Jie; Hu Jian; Jianwen Zhang

    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,...

  15. Influence of physical and chemical factors on biological leaching process of copper from printed circuit boards

    OpenAIRE

    Willner, J

    2013-01-01

    The article presents the results of the research regarding the biological leaching of this metal from electronic wastes components in the form of printed circuit boards. The purpose of the study was to evaluate the influence of some physical and chemical factors (e.g. pH, oxidation-reduction potential) on bioleaching process and efficiency of copper transfer from solid phase into solution. Bioleaching experiments were carried out with pure cultures of Acidithiobacillus ferrooxidans. The obtai...

  16. Influence Of Used Bacterial Culture On Zinc And Aluminium Bioleaching From Printed Circuit Boards

    OpenAIRE

    Mrazikova Anna; Marcincakova Renata; Kadukova Jana; Velgosova Oksana; Balintova Magdalena

    2015-01-01

    Bioleaching processes were used to solubilize metals (Cu, Ni, Zn and Al) from printed circuit boards (PCBs). In this study, a PCBs-adapted pure culture of Acidithiobacillus ferrooxidans, pure culture of Acidithiobacillus thiooxidans and PCBs-adapted mixed culture of A. ferrooxidans and A. thiooxidans were used for recovery of the metals. The study showed that the mixed bacterial culture has the greatest potential to dissolve metals. The maximum metal bioleaching efficiencies were found to be ...

  17. Computing Hypergraph Ramsey Numbers by Using Quantum Circuit

    OpenAIRE

    Qu, Ri; Li, Zong-shang; WANG, Juan; Bao, Yan-ru; Cao, Xiao-chun

    2012-01-01

    Gaitan and Clark [Phys. Rev. Lett. 108, 010501 (2012)] have recently shown a quantum algorithm for the computation of the Ramsey numbers using adiabatic quantum evolution. We present a quantum algorithm to compute the two-color Ramsey numbers for r-uniform hypergraphs by using the quantum counting circuit.

  18. Products Made from Nonmetallic Materials Reclaimed from Waste Printed Circuit Boards

    Institute of Scientific and Technical Information of China (English)

    MOU Peng; XIANG Dong; DUAN Guanghong

    2007-01-01

    Printed circuit boards (PCBs) are in all electronic equipment, so with the sharp increase of electronic waste, the recovery of PCB components has become a critical research field. This paper presents a study of the reclaimation and reuse of nonmetallic materials recovered from waste PCBs. Mechanical processes, such as crushing, milling, and separation, were used to process waste PCBs. Nonmetallic materials in the PCBs were separated using density-based separation with separation rates in excess of 95%. The recovered nonmetals were used to make models, construction materials, composite boards, sewer grates,and amusement park boats. The PCB nonmetal products have better mechanical characteristics and durability than traditional materials and fillers. The flexural strength of the PCB nonmetallic material composite boards is 30% greater than that of standard products. Products derived from PCB waste processing have been brought into industrial production. The study shows that PCB nonmetals can be reused in profitable and environmentally friendly ways.

  19. Constant-Overhead Secure Computation of Boolean Circuits using Preprocessing

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Zakarias, Sarah Nouhad Haddad

    We present a protocol for securely computing a Boolean circuit $C$ in presence of a dishonest and malicious majority. The protocol is unconditionally secure, assuming access to a preprocessing functionality that is not given the inputs to compute on. For a large number of players the work done...... by each player is the same as the work needed to compute the circuit in the clear, up to a constant factor. Our protocol is the first to obtain these properties for Boolean circuits. On the technical side, we develop new homomorphic authentication schemes based on asymptotically good codes...... with an additional multiplication property. We also show a new algorithm for verifying the product of Boolean matrices in quadratic time with exponentially small error probability, where previous methods would only give a constant error....

  20. Computer Science and Telecommunications Board summary of activities

    Energy Technology Data Exchange (ETDEWEB)

    Blumenthal, M.S.

    1992-03-27

    The Computer Science and Telecommunications Board (CSTB) considers technical and policy issues pertaining to computer science, telecommunications, and associated technologies. CSTB actively disseminates the results of its completed projects to those in a position to help implement their recommendations or otherwise use their insights. It provides a forum for the exchange of information on computer science, computing technology, and telecommunications. This report discusses the major accomplishments of CSTB.

  1. Computation and physics: Wheeler's meaning circuit?

    International Nuclear Information System (INIS)

    Computation is a physical process, inevitably utilizing physical degrees of freedom. Computation, therefore, is restricted by the laws of physics and also by the construction material and operating environments available in our actual universe. These restrictions have been investigated for a quarter century. A discussion of this field is provided, too concise to be a review, but only intended as a guide to the literature. Physical law, in turn, consists of algorithms for information processing. Therefore, the ultimate form of physical laws must be consistent with the restrictions on the physical executability of algorithms, which is in turn dependent on physical law

  2. A neural circuit for angular velocity computation

    Directory of Open Access Journals (Sweden)

    Samuel B Snider

    2010-12-01

    Full Text Available In one of the most remarkable feats of motor control in the animal world, some Diptera, such as the housefly, can accurately execute corrective flight maneuvers in tens of milliseconds. These reflexive movements are achieved by the halteres, gyroscopic force sensors, in conjunction with rapidly-tunable wing-steering muscles. Specifically, the mechanosensory campaniform sensilla located at the base of the halteres transduce and transform rotation-induced gyroscopic forces into information about the angular velocity of the fly's body. But how exactly does the fly's neural architecture generate the angular velocity from the lateral strain forces on the left and right halteres? To explore potential algorithms, we built a neuro-mechanical model of the rotation detection circuit. We propose a neurobiologically plausible method by which the fly could accurately separate and measure the three-dimensional components of an imposed angular velocity. Our model assumes a single sign-inverting synapse and formally resembles some models of directional selectivity by the retina. Using multidimensional error analysis, we demonstrate the robustness of our model under a variety of input conditions. Our analysis reveals the maximum information available to the fly given its physical architecture and the mathematics governing the rotation-induced forces at the haltere's end knob.

  3. A neural circuit for angular velocity computation.

    Science.gov (United States)

    Snider, Samuel B; Yuste, Rafael; Packer, Adam M

    2010-01-01

    In one of the most remarkable feats of motor control in the animal world, some Diptera, such as the housefly, can accurately execute corrective flight maneuvers in tens of milliseconds. These reflexive movements are achieved by the halteres, gyroscopic force sensors, in conjunction with rapidly tunable wing steering muscles. Specifically, the mechanosensory campaniform sensilla located at the base of the halteres transduce and transform rotation-induced gyroscopic forces into information about the angular velocity of the fly's body. But how exactly does the fly's neural architecture generate the angular velocity from the lateral strain forces on the left and right halteres? To explore potential algorithms, we built a neuromechanical model of the rotation detection circuit. We propose a neurobiologically plausible method by which the fly could accurately separate and measure the three-dimensional components of an imposed angular velocity. Our model assumes a single sign-inverting synapse and formally resembles some models of directional selectivity by the retina. Using multidimensional error analysis, we demonstrate the robustness of our model under a variety of input conditions. Our analysis reveals the maximum information available to the fly given its physical architecture and the mathematics governing the rotation-induced forces at the haltere's end knob. PMID:21228902

  4. Operating a Computer Bulletin Board System for Psychiatrists and Psychologists

    OpenAIRE

    Miller, Marvin J.

    1988-01-01

    A computer Bulletin Board System (BBS) provides messaging and file transfer functions for a professional organization. It allows ready access to clinical computer programs at minimal cost. Ways to encourage development of public domain clinical software and its distribution through BBSs are discussed.

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

    International Nuclear Information System (INIS)

    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. (paper)

  6. An Innovative On-Board Computer for Space Robot

    Institute of Scientific and Technical Information of China (English)

    WEI Ran; JIN Ming-he; XIA Jin-jun; LIU Hong

    2007-01-01

    In this paper an on-board computer system for the first Chinese Intelligent Space Robotic System was presented. A fault tolerance design on on-board computer (OBC) was proposed that allows commercial-off-theshelf (COTS) devices to be incorporated into dual processing modules of on-board computer. The processing module is composed of 32-bit ARM RISC processor and other COTS devices. This innovative approach deeply relies on light weight/low cost equipment development using commercial miniaturized parts and non-space qualified technologies. As well as, a set of fault handling mechanisms was implemented in the computer system. The on-board software was organized around a set of processes that communicate between each other through a routing process.The qualification experiment shows that the fault tolerant on-board computer has excellent data processing capability and is enough to meet the demanding of the extremely tight constraints on mass, volume, power consumption and space environmental conditions.

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

    International Nuclear Information System (INIS)

    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

  8. Pyrolysis characteristics of integrated circuit boards at various particle sizes and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, H.-L. [Department Risk Management, China Medical University, Taichung 40402, Taiwan (China)], E-mail: hlchiang@mail.cmu.edu.tw; Lin, K.-H. [Department of Environmental Engineering, Fooyin University, Kaohsiung 831, Taiwan (China); Lai, M.-H. [Department of Environmental Engineering, Dayeh University, Changhua 51591, Taiwan (China); Chen, T.-C. [Department of Environmental Science and Engineering, Pingtung University of Science and Technology, Pingtung 91201, Taiwan (China); Ma, S.-Y. [Department of Environmental Engineering, Fooyin University, Kaohsiung 831, Taiwan (China)

    2007-10-01

    A pyrolysis method was employed to recycle the metals and brominated compounds blended into printed circuit boards. This research investigated the effect of particle size and process temperature on the element composition of IC boards and pyrolytic residues, liquid products, and water-soluble ionic species in the exhaust, with the overall goal being to identify the pyrolysis conditions that will have the least impact on the environment. Integrated circuit (IC) boards were crushed into 5-40 mesh (0.71-4.4 mm), and the crushed particles were pyrolyzed at temperatures ranging from 200 to 500 deg. C. The thermal decomposition kinetics were measured by a thermogravimetric (TG) analyzer. The composition of pyrolytic residues was analyzed by Energy Dispersive X-ray Spectrometer (EDS), Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). In addition, the element compositions of liquid products were analyzed by ICP-AES and ICP-MS. Pyrolytic exhaust was collected by a water-absorption system in an ice-bath cooler, and IC analysis showed that the absorbed solution comprised 11 ionic species. Based on the pyrolytic kinetic parameters of TG analysis and pyrolytic residues at various temperatures for 30 min, the effect of particle size was insignificant in this study, and temperature was the key factor for the IC board pyrolysis. Two stages of decomposition were found for IC board pyrolysis under nitrogen atmosphere. The activation energy was 38-47 kcal/mol for the first-stage reaction and 5.2-9.4 kcal/mol for the second-stage reaction. Metal content was low in the liquid by-product of the IC board pyrolysis process, which is an advantage in that the liquid product could be used as a fuel. Brominate and ammonium were the main water-soluble ionic species of the pyrolytic exhaust. A plan for their safe and effective disposal must be developed if the pyrolytic recycling process is to be applied to IC boards.

  9. Constant-overhead secure computation of Boolean circuits using preprocessing

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Zakarias, S.

    2013-01-01

    We present a protocol for securely computing a Boolean circuit C in presence of a dishonest and malicious majority. The protocol is unconditionally secure, assuming a preprocessing functionality that is not given the inputs. For a large number of players the work for each player is the same...

  10. Bioleaching of metals from printed circuit boards supported with surfactant-producing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Karwowska, Ewa, E-mail: ewa.karwowska@is.pw.edu.pl [Warsaw University of Technology, Faculty of Environmental Engineering, Biology Division, Nowowiejska 20, 00-653 Warsaw (Poland); Andrzejewska-Morzuch, Dorota; Łebkowska, Maria [Warsaw University of Technology, Faculty of Environmental Engineering, Biology Division, Nowowiejska 20, 00-653 Warsaw (Poland); Tabernacka, Agnieszka, E-mail: agnieszka.tabernacka@is.pw.edu.pl [Warsaw University of Technology, Faculty of Environmental Engineering, Biology Division, Nowowiejska 20, 00-653 Warsaw (Poland); Wojtkowska, Małgorzata; Telepko, Alicja; Konarzewska, Agnieszka [Warsaw University of Technology, Faculty of Environmental Engineering, Nowowiejska 20, 00-653 Warsaw (Poland)

    2014-01-15

    Highlights: • Bioleaching of metals from printed circuit boards by BSAC-producing bacteria was estimated. • Aeration increased the release of all metals in medium with sulphur and biosurfactant. • Increase in Cu, Pb, Ni and Cr removal rate was observed at 37 °C in acidic medium. -- Abstract: This study has evaluated the possibility of bioleaching zinc, copper, lead, nickel, cadmium and chromium from printed circuit boards by applying a culture of sulphur-oxidising bacteria and a mixed culture of biosurfactant-producing bacteria and sulphur-oxidising bacteria. It was revealed that zinc was removed effectively both in a traditional solution acidified by a way of microbial oxidation of sulphur and when using a microbial culture containing sulphur-oxidising and biosurfactant-producing bacteria. The average process efficiency was 48% for Zn dissolution. Cadmium removal was similar in both media, with a highest metal release of 93%. For nickel and copper, a better effect was obtained in the acidic medium, with a process effectiveness of 48.5% and 53%, respectively. Chromium was the only metal that was removed more effectively in the bioleaching medium containing both sulphur-oxidising and biosurfactant-producing bacteria. Lead was removed from the printed circuit boards with very low effectiveness (below 0.5%). Aerating the culture medium with compressed air increased the release of all metals in the medium with sulphur and biosurfactant, and of Ni, Cu, Zn and Cr in the acidic medium. Increasing the temperature of the medium (to 37 °C) had a more significant impact in the acidic environment than in the neutral environment.

  11. Bioleaching of metals from printed circuit boards supported with surfactant-producing bacteria

    International Nuclear Information System (INIS)

    Highlights: • Bioleaching of metals from printed circuit boards by BSAC-producing bacteria was estimated. • Aeration increased the release of all metals in medium with sulphur and biosurfactant. • Increase in Cu, Pb, Ni and Cr removal rate was observed at 37 °C in acidic medium. -- Abstract: This study has evaluated the possibility of bioleaching zinc, copper, lead, nickel, cadmium and chromium from printed circuit boards by applying a culture of sulphur-oxidising bacteria and a mixed culture of biosurfactant-producing bacteria and sulphur-oxidising bacteria. It was revealed that zinc was removed effectively both in a traditional solution acidified by a way of microbial oxidation of sulphur and when using a microbial culture containing sulphur-oxidising and biosurfactant-producing bacteria. The average process efficiency was 48% for Zn dissolution. Cadmium removal was similar in both media, with a highest metal release of 93%. For nickel and copper, a better effect was obtained in the acidic medium, with a process effectiveness of 48.5% and 53%, respectively. Chromium was the only metal that was removed more effectively in the bioleaching medium containing both sulphur-oxidising and biosurfactant-producing bacteria. Lead was removed from the printed circuit boards with very low effectiveness (below 0.5%). Aerating the culture medium with compressed air increased the release of all metals in the medium with sulphur and biosurfactant, and of Ni, Cu, Zn and Cr in the acidic medium. Increasing the temperature of the medium (to 37 °C) had a more significant impact in the acidic environment than in the neutral environment

  12. Superconducting optoelectronic circuits for neuromorphic computing

    CERN Document Server

    Shainline, Jeffrey M; Mirin, Richard P; Nam, Sae Woo

    2016-01-01

    We propose a hybrid semiconductor-superconductor hardware platform for the implementation of neural networks and large-scale neuromorphic computing. The platform combines semiconducting few-photon light-emitting diodes with superconducting-nanowire single-photon detectors to behave as spiking neurons. These processing units are connected via a network of optical waveguides, and variable weights of connection can be implemented using several approaches. The use of light as a signaling mechanism overcomes the requirement for time-multiplexing that has limited the event rates of purely electronic platforms. The proposed processing units can operate at $20$ MHz with fully asynchronous activity, light-speed-limited latency, and power densities on the order of 1 mW/cm$^2$ for neurons with 700 connections operating at full speed at 2 K. The processing units achieve an energy efficiency of $\\approx 20$ aJ per synapse event. By leveraging multilayer photonics with low-temperature-deposited waveguides and superconducto...

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hooker, Matthew [Composite Tehcnology Development, Inc., Lafayette, CO (United States); Fabian, Paul [Composite Tehcnology Development, Inc., Lafayette, CO (United States)

    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

  15. Deterministic linear optics quantum computation utilizing linked photon circuits

    CERN Document Server

    Yoran, N; Yoran, Nadav; Reznik, Benni

    2003-01-01

    We suggest an efficient scheme for quantum computation with linear optical elements utilizing "linked" photon states. The linked states are designed according to the particular quantum circuit one wishes to process. Once a linked-state has been successfully prepared, the computation is pursued deterministically by a sequence of teleportation steps. The present scheme enables a significant reduction of the average number of elementary gates per logical gate to about 20-30 CZ_{9/16} gates.

  16. Kinetic Study of the Pyrolysis of Waste Printed Circuit Boards Subject to Conventional and Microwave Heating

    OpenAIRE

    Chunyuan Ma; Chao Zhao; Qingluan Ma; Zhen Liu; Wenlong Wang; Jing Sun

    2012-01-01

    This paper describes a kinetic study of the decomposition of waste printed circuit boards (WPCB) under conventional and microwave-induced pyrolysis conditions. We discuss the heating rates and the influence of the pyrolysis on the thermal decomposition kinetics of WPCB. We find that the thermal degradation of WPCB in a controlled conventional thermogravimetric analyzer (TGA) occurred in the temperature range of 300 °C–600 °C, where the main pyrolysis of organic matter takes place along wi...

  17. Microstepping Test Board with LMD 18245 Specialized Circuit for Bipolar Stepper Motor

    Directory of Open Access Journals (Sweden)

    Alexandru Morar

    2010-12-01

    Full Text Available The paper presents a control system for low speed stepper motor control in a microstepping mode, which was designed and performed with a high performant specialized integrated circuit LMD 18245, made by National Semiconductor company. The microstepping control system improves the positioning accuracy and eliminates low speed ripple and resonance effects in a stepper motor electric drive. The same microstepping system is ideal for robotics, printers, plotters, X-Y-Z tables and can facilitate the construction of very sophisticated positioning control systems while significantly reducing component cost, board space, design time and systems cost. The microstepping card is designed for continuous operation.

  18. Influence of physical and chemical factors on biological leaching process of copper from printed circuit boards

    Directory of Open Access Journals (Sweden)

    J. Willner

    2013-04-01

    Full Text Available The article presents the results of the research regarding the biological leaching of this metal from electronic wastes components in the form of printed circuit boards. The purpose of the study was to evaluate the influence of some physical and chemical factors (e.g. pH, oxidation-reduction potential on bioleaching process and efficiency of copper transfer from solid phase into solution. Bioleaching experiments were carried out with pure cultures of Acidithiobacillus ferrooxidans. The obtained results were discussed.

  19. Computer presentation of the closed circuits in mineral processing by software computer packets

    OpenAIRE

    Krstev, Aleksandar; Krstev, Boris; Golomeov, Blagoj

    2009-01-01

    In this paper will be shown computer application of softwares Minteh-1, Minteh-2 and Minteh-3 in Visual Basic, Visual Studio for presentation of two-products for some closed circuits od grinding-clasifying processes. These methods make possibilities for appropriate, fasr and sure presentation of some complex circuits in the mineral processing technologies.

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

    International Nuclear Information System (INIS)

    Highlights: ► An integrated printed circuit board (PCB) based array sensing chip was developed. ► Simultaneous detection of lactate and glucose in serum has been demonstrated. ► The array electronic biochip has high signal to noise ratio and high sensitivity. ► Additional electrodes were designed on the chip to correct interferences. -- Abstract: 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

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

    Science.gov (United States)

    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.

  2. Distribution of heavy metals during pyrolysis of waste printed circuit boards

    Institute of Scientific and Technical Information of China (English)

    PENG Shao-hong; CHEN Lie-qiang; CAI Ming-zhao; WANG Yun-yu

    2006-01-01

    The volatilization behavior of Cu, Pb, Sn, Sb, Ni, Zn, Mn, Co, Cr, Cd during pyrolysis of waste printed circuit boards was investigated in a bench-scale fixed-bed pyrolysis system. It was found that volatility of heavy metals increases with operating temperature elevating, and bromine and vacuum have an obvious promoting effect on volatility of most of heavy metals. Over 99% weight of Cu and Ni are still remained in solid residue after pyrolysis, about 20% weight of Sb, Zn and Cd are transfered into liquid and gas during a pyrolysis process at 600 ℃, volatilization fractions of Pb, Sn, Mn, Co, Cr are less than 10% at the same conditions. The contents of heavy metals in liquid and gas products depend on not only volatility of metals, but also their initial contents in printed circuit boards, pyrolysis liquid and gas are primarily contaminated by Cu, Pb, Sn,Sb and Zn, their contents in liquid vary from 102 to 103 μg/mL, Mn, Co, Cr, Cd were detected only at very low level, less than 10 μg/mL.

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

    Science.gov (United States)

    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. PMID:26239442

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

    Science.gov (United States)

    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. PMID:26117419

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

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xuelian [Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing 400715 (China); School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Zang, Jianfeng [Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708 (United States); Liu, Yingshuai; Lu, Zhisong [Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing 400715 (China); Li, Qing, E-mail: Qli@swu.edu.cn [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Li, Chang Ming, E-mail: ecmli@swu.edu.cn [Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing 400715 (China)

    2013-04-10

    Highlights: ► An integrated printed circuit board (PCB) based array sensing chip was developed. ► Simultaneous detection of lactate and glucose in serum has been demonstrated. ► The array electronic biochip has high signal to noise ratio and high sensitivity. ► Additional electrodes were designed on the chip to correct interferences. -- Abstract: 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.

  6. Recovering metals from printed circuit board scrap by a mechanical separation process

    Institute of Scientific and Technical Information of China (English)

    XU Min; LI Guang-ming; HE Wen-zhi; LI Hui

    2008-01-01

    A mechanical separation process was developed for recovering metals from printed circuit board (PCB) scrap; it included three steps: impact crushing, sieving and fluidization separation. The mechanism of the technique was based on the difference in the crushabilities of metallic and nonmetallic materials in the PCBs that led to the concentrated distribution of metals in particles of larger sizes and nonmetals mostly in particles of smaller sizes. It was found that crushed PCB particles from 0.125 mm to 1.000 mm contained about 80% of metals in the PCBs. Metals acquired satisfactory liberation in particles smaller than 0.800 mm. The crushed PCB particles were sieved into fractions of different size ranges. Each fraction separately went through a gas-solid fluidized bed operating at a selected optimal gas velocity for the specific size range. Approximately 95% of metals in printed circuit board particles from 0.125 mm to 0.800 mm was recovered by the gas-fluidized bed separator at the selected optimal gas velocity. However, separation of metals from particles smaller than 0.125 mm was not satisfactory. Further study is needed on metal recovery from fine particles.

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

    Science.gov (United States)

    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

  8. Comparative Study of Crosstalk Reduction Techniques in RF Printed Circuit Board Using FDTD Method

    Directory of Open Access Journals (Sweden)

    Rajeswari Packianathan

    2015-01-01

    Full Text Available Miniaturization of the feature size in modern electronic circuits results from placing interconnections in close proximity with a high packing density. As a result, coupling between the adjacent lines has increased significantly, causing crosstalk to become an important concern in high-performance circuit design. In certain applications, microstriplines may be used in printed circuit boards for propagating high-speed signals, rather than striplines. Here, the electromagnetic coupling effects are analyzed for various microstrip transmission line structures, namely, microstriplines with a guard trace, double stub microstriplines, and parallel serpentine microstriplines using the finite-difference time-domain method. The numerical results are compared with simulation results, where the variants are simulated using an Ansoft high-frequency structure simulator. The analysis and simulation results are experimentally validated by fabricating a prototype and establishing a good correspondence between them. Numerical results are compared with simulation and experimental results, showing that double stub microstriplines reduce the far end crosstalk by 7 dB and increase the near end crosstalk by about 2 dB compared with the parallel microstriplines. Parallel serpentine microstriplines reduce the far end crosstalk by more than 10 dB and also reduce more than 15 mV of peak far end crosstalk voltage, compared with parallel microstriplines.

  9. Hierarchical computation in the canonical auditory cortical circuit

    OpenAIRE

    Atencio, Craig A.; Sharpee, Tatyana O.; Christoph E Schreiner

    2009-01-01

    Sensory cortical anatomy has identified a canonical microcircuit underlying computations between and within layers. This feed-forward circuit processes information serially from granular to supragranular and to infragranular layers. How this substrate correlates with an auditory cortical processing hierarchy is unclear. We recorded simultaneously from all layers in cat primary auditory cortex (AI) and estimated spectrotemporal receptive fields (STRFs) and associated nonlinearities. Spike-trig...

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

    Energy Technology Data Exchange (ETDEWEB)

    Hadi, Pejman; Ning, Chao; Ouyang, Weiyi; Xu, Meng [Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong Special Administrative Region (Hong Kong); Lin, Carol S.K. [School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong Special Administrative Region (Hong Kong); McKay, Gordon, E-mail: kemckayg@ust.hk [Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong Special Administrative Region (Hong Kong); Division of Sustainable Development, College of Science, Engineering and Technology, Hamad bin Khalifa University, Doha (Qatar)

    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.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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

  13. Uncertain behaviours of integrated circuits improve computational performance.

    Science.gov (United States)

    Yoshimura, Chihiro; Yamaoka, Masanao; Hayashi, Masato; Okuyama, Takuya; Aoki, Hidetaka; Kawarabayashi, Ken-ichi; Mizuno, Hiroyuki

    2015-01-01

    Improvements to the performance of conventional computers have mainly been achieved through semiconductor scaling; however, scaling is reaching its limitations. Natural phenomena, such as quantum superposition and stochastic resonance, have been introduced into new computing paradigms to improve performance beyond these limitations. Here, we explain that the uncertain behaviours of devices due to semiconductor scaling can improve the performance of computers. We prototyped an integrated circuit by performing a ground-state search of the Ising model. The bit errors of memory cell devices holding the current state of search occur probabilistically by inserting fluctuations into dynamic device characteristics, which will be actualised in the future to the chip. As a result, we observed more improvements in solution accuracy than that without fluctuations. Although the uncertain behaviours of devices had been intended to be eliminated in conventional devices, we demonstrate that uncertain behaviours has become the key to improving computational performance. PMID:26586362

  14. NOTE: Plated through-hole vias in a porous polyimide foil for flexible printed circuit boards

    Science.gov (United States)

    Yousef, Hanna; Hjort, Klas; Lindeberg, Mikael

    2008-01-01

    A fabrication process for high aspect ratio plated through-hole vias is presented for flexible printed circuit boards. A 75 µm thick porous Kapton foil that allows direct definition of high aspect ratio through-hole vias by dry photoresist film lithography and electrodeposition is presented. Pretreatment with swift heavy ion irradiation and wet etching define the pore density and porosity of the foil, similar to ion-track-etched filter membranes. Thin film metallization of a seed layer and lithography of a laminated dry photoresist film define the via sizes and positions. Subsequent through-hole electrodeposition produces vias consisting of multiple wires, where each open pore defines one wire. The via geometries are characterized by scanning electron microscopy. The electrical properties of the vias are characterized by resistance measurements. Vias with an aspect ratio over 2 and a side length of 33 µm show high yield with low resistance and low variation in resistance.

  15. Environmental friendly automatic line for recovering metal from waste printed circuit boards.

    Science.gov (United States)

    Li, Jia; Xu, Zhenming

    2010-02-15

    The technology industrialization was the final goal of the research. A set of automatic line without negative impact to environment for recycling waste printed circuit boards (PCB) in industry-scale was investigated in this study. The independent technologies were integrated and many problems in the process of technology industrialization were solved. The whole technology contained four parts: multiple scarping, material screening, multiple-roll corona electrostatic separator, and dust precipitation. The output of this automatic line reached 600 kg/h and the recovery rate of copper reached 95%. After separation, the metal and nonmetal products were totally reused. Compared with other production lines (traditional fluid bed production line and processing from developed countries), the automatic line has lower energy consumption and better technology rationality. The cost of this line was in acceptable level for local processors. PMID:20092305

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  19. STUDY ON INFRARED PBS DETECTOR PREPARED USING COPPER ELECTRODES OF PRINTED CIRCUIT BOARD

    Directory of Open Access Journals (Sweden)

    Hariyadi Soetedjo

    2013-01-01

    Full Text Available Copper layers of Printed Circuit Board (PCB have been used as electrodes for PbS infrared structure detector to introduce low cost and simple in preparation. PbS deposition as an active layer detector has been prepared for a few micrometers in thickness using an evaporation technique under vacuum pressure at 10-6 Torr. Photoconductivity phenomenon has been observed from the measurement when IR radiation of a Tungsten lamp introduced to the detector. The sensitivity of the detector respects to the variation of radiation intensities was also observed. The results showed that the detector has good sensitivity indicated by rapid drop voltages at a short-wavelength IR region (1-3 µm. This phenomenon is encouraging for further applications of detector prepared using the electrodes from a commercialized PCB.

  20. Influence Of Used Bacterial Culture On Zinc And Aluminium Bioleaching From Printed Circuit Boards

    Directory of Open Access Journals (Sweden)

    Mrazikova Anna

    2015-06-01

    Full Text Available Bioleaching processes were used to solubilize metals (Cu, Ni, Zn and Al from printed circuit boards (PCBs. In this study, a PCBs-adapted pure culture of Acidithiobacillus ferrooxidans, pure culture of Acidithiobacillus thiooxidans and PCBs-adapted mixed culture of A. ferrooxidans and A. thiooxidans were used for recovery of the metals. The study showed that the mixed bacterial culture has the greatest potential to dissolve metals. The maximum metal bioleaching efficiencies were found to be 100, 92, 89 and 20% of Cu, Ni, Zn and Al, respectively. The mixed culture revealed higher bacterial stability. The main factor responsible for high metal recovery was the ability of the mixed culture to maintain the low pH during the whole process. The pure culture of A. thiooxidans had no significant effect on metal bioleaching from PCBs.

  1. Contamination profile on typical printed circuit board assemblies vs soldering process

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2014-01-01

    Purpose – The purpose of this paper was to analyse typical printed circuit board assemblies (PCBAs) processed by reflow, wave or selective wave soldering for typical levels of process-related residues, resulting from a specific or combination of soldering processes. Typical solder flux residue...... distribution pattern, composition and concentration are profiled and reported. The effect of such contaminants on conformal coating was tested. Design/methodology/approach – Presence of localized flux residues was visualized using a commercial residue reliability assessment testing gel test and chemical...... out using a commercial critical contamination control extraction system. Findings – Results clearly show that the amount and distribution of flux residues are a function of the soldering process, and the level can be reduced by an appropriate cleaning. Selective soldering process generates...

  2. Contamination profile of Printed Circuit Board Assemblies in relation to soldering types and conformal coating

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2014-01-01

    Typical printed circuit board assemblies (PCBAs) processed by reflow, wave, or selective wave soldering were analysed for typical levels of process related residues, resulting from a specific or combination of soldering process. Typical solder flux residue distribution pattern, composition......, and concentration are profiled and reported. Presence of localized flux residues were visualized using a commercial Residue RAT gel test and chemical structure was identified by FT-IR, while the concentration was measured using ion chromatography, and the electrical properties of the extracts were determined...... by measuring the leak current using a twin platinum electrode setup. Localized extraction of residue was carried out using a commercial C3 extraction system. Results clearly show that the amount and distribution of flux residues are a function of the soldering process, and the level can be reduced...

  3. Plated through-hole vias in a porous polyimide foil for flexible printed circuit boards

    International Nuclear Information System (INIS)

    A fabrication process for high aspect ratio plated through-hole vias is presented for flexible printed circuit boards. A 75 µm thick porous Kapton foil that allows direct definition of high aspect ratio through-hole vias by dry photoresist film lithography and electrodeposition is presented. Pretreatment with swift heavy ion irradiation and wet etching define the pore density and porosity of the foil, similar to ion-track-etched filter membranes. Thin film metallization of a seed layer and lithography of a laminated dry photoresist film define the via sizes and positions. Subsequent through-hole electrodeposition produces vias consisting of multiple wires, where each open pore defines one wire. The via geometries are characterized by scanning electron microscopy. The electrical properties of the vias are characterized by resistance measurements. Vias with an aspect ratio over 2 and a side length of 33 µm show high yield with low resistance and low variation in resistance. (note)

  4. Pollutant emissions during pyrolysis and combustion of waste printed circuit boards, before and after metal removal

    Energy Technology Data Exchange (ETDEWEB)

    Ortuño, Nuria; Conesa, Juan A., E-mail: ja.conesa@ua.es; Moltó, Julia; Font, Rafael

    2014-11-15

    The constant increase in the production of electronic devices implies the need for an appropriate management of a growing number of waste electrical and electronic equipment. Thermal treatments represent an interesting alternative to recycle this kind of waste, but particular attention has to be paid to the potential emissions of toxic by-products. In this study, the emissions from thermal degradation of printed circuit boards (with and without metals) have been studied using a laboratory scale reactor, under oxidizing and inert atmosphere at 600 and 850 °C. Apart from carbon oxides, HBr was the main decomposition product, followed by high amounts of methane, ethylene, propylene, phenol and benzene. The maximum formation of PAHs was found in pyrolysis at 850 °C, naphthalene being the most abundant. High levels of 2-, 4-, 2,4-, 2,6- and 2,4,6-bromophenols were found, especially at 600 °C. Emissions of PCDD/Fs and dioxin-like PCBs were quite low and much lower than that of PBDD/Fs, due to the higher bromine content of the samples. Combustion at 600 °C was the run with the highest PBDD/F formation: the total content of eleven 2,3,7,8-substituted congeners (tetra- through heptaBDD/Fs) was 7240 and 3250 ng WHO{sub 2005}-TEQ/kg sample, corresponding to the sample with and without metals, respectively. - Highlights: • Thermal decomposition of printed circuit boards (with and without metals) is studied. • Important differences were found at the different experimental conditions. • Emission of brominated pollutants is much higher than that of chlorinated. • Metal enhances emission of halogenated compounds. • An increase in the temperature produces the destruction of pollutants.

  5. Catalytic Pyrolysis and a Pyrolysis Kinetic Study of Shredded Printed Circuit Board for Fuel Recovery

    Directory of Open Access Journals (Sweden)

    Salmiaton Ali

    2014-10-01

    Full Text Available Scrap printed circuit boards (PCBs are the most abundant wastes that can be found in the landfills in Malaysia and this disposal certainly poses serious detrimental to the environment. This research aims to investigate optimum temperature for pyrolyzing waste PCBs, find out the best catalyst to be used in accelerating PCBs’ pyrolysis, select suitable ratio of catalyst to PCBs for higher oil yield and examine kinetics pyrolysis of the waste PCBs’ decomposition. Operating temperatures ranged from 200 to 350 ˚C of PCB’s pyrolysis were conducted with the optimum temperature obtained was 275 ˚C. Fluid cata-lytic cracking (FCC catalyst, zeolite socony mobil-5 (ZSM-5, H-Y-type zeolite and dolomite were used to accelerate PCB’s pyrolysis at 275 ˚C and FCC was identified as the best catalyst to be used. Differ-ent ratios of FCC to waste PCBs such as 10:90, 20:80, 30:70, 40:60 and 50:50 were applied in the pyro-lysis at 275 ˚C and ratio of 10:90 was selected as the suitable ratio to be utilized for maximum yield. The kinetic study was done through thermogravimetric analysis on waste PCBs under various heating rates and different particle sizes. The GC-MS analysis revealed that compounds detected in the pyro-oil have the potential to be used as fuel. © 2014 BCREC UNDIP. All rights reservedReceived: 23rd July 2014; Revised: 14th August 2014; Accepted: 14th August 2014 How to Cite: Ng, C.H., Salmiaton, A., Hizam, H. (2014. Catalytic Pyrolysis and a Pyrolysis Kinetic Study of Shredded Printed Circuit Board for Fuel Recovery. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (3: 224-240. (doi:10.9767/bcrec.9.3.7148.224-240 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.7148.224-240

  6. Pollutant emissions during pyrolysis and combustion of waste printed circuit boards, before and after metal removal

    International Nuclear Information System (INIS)

    The constant increase in the production of electronic devices implies the need for an appropriate management of a growing number of waste electrical and electronic equipment. Thermal treatments represent an interesting alternative to recycle this kind of waste, but particular attention has to be paid to the potential emissions of toxic by-products. In this study, the emissions from thermal degradation of printed circuit boards (with and without metals) have been studied using a laboratory scale reactor, under oxidizing and inert atmosphere at 600 and 850 °C. Apart from carbon oxides, HBr was the main decomposition product, followed by high amounts of methane, ethylene, propylene, phenol and benzene. The maximum formation of PAHs was found in pyrolysis at 850 °C, naphthalene being the most abundant. High levels of 2-, 4-, 2,4-, 2,6- and 2,4,6-bromophenols were found, especially at 600 °C. Emissions of PCDD/Fs and dioxin-like PCBs were quite low and much lower than that of PBDD/Fs, due to the higher bromine content of the samples. Combustion at 600 °C was the run with the highest PBDD/F formation: the total content of eleven 2,3,7,8-substituted congeners (tetra- through heptaBDD/Fs) was 7240 and 3250 ng WHO2005-TEQ/kg sample, corresponding to the sample with and without metals, respectively. - Highlights: • Thermal decomposition of printed circuit boards (with and without metals) is studied. • Important differences were found at the different experimental conditions. • Emission of brominated pollutants is much higher than that of chlorinated. • Metal enhances emission of halogenated compounds. • An increase in the temperature produces the destruction of pollutants

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

    International Nuclear Information System (INIS)

    Highlights: • Recycling of waste printed circuit boards is an important issue. • Pyrolysis is an emerging technology for PCB treatment. • Emission factors of VOCs are determined for PCB pyrolysis exhaust. • Iron-Al2O3 catalyst was employed for the exhaust control. -- Abstract: 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 0–0.7 mg/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. Preparation and characterization of superconductor thin films for application in printed circuit boards

    International Nuclear Information System (INIS)

    Full text: Since the discovery of high temperature superconductors (HTS) many studies have been performed, in terms to discover new materials with higher critical temperature and its potential applications. Technological advances have induced to use superconductor materials in the development of new devices that have higher processing speed, storage capacity and are miniaturized, what may imply in great evolution in the electronic area. Thinking about that advances and looking to supply some requirements, this work proposed to prepare a printed circuit board (PCB) with a superconductor thin film using an inexpensive and conventional photographic method. This work was divided in two steps: synthesis of the precursor solution and film preparation for superconductor printed circuit. In the preparation of superconductor thin film was considered to use the 2223 phase of the BSCCO system, which has been doped with Pb (BPSCCO) for stabilizing the same, and it presents a critical temperature around 110 K. This film was prepared from a precursor solution based on similar method developed by M. P. Pechini. The printed circuit was created by the photographic method of heat transfer which consisted of creation a circuit layout, with different dimensions and printed on photo paper (Epson S041140). The layout was transferred to the FR4 printed copper clad laminate was made with the household clothes iron. The precursor solution was deposited on Si substrate by spin-coating. The control of film thickness was performed by the deposition number that in this case was done five subsequent depositions to obtain an ideal thickness. Between each deposition the film was submitted to calcinations in order to eliminate organic matter. After that the film was submitted a heat treatment around 820 deg C / 5 minutes to obtain the expected superconducting phase and coupling and the grain growth. Film characterizations were made using optical microscopy, XRD and EDX, to check the dimensions and

  9. Virtualizing Super-Computation On-Board Uas

    Science.gov (United States)

    Salami, E.; Soler, J. A.; Cuadrado, R.; Barrado, C.; Pastor, E.

    2015-04-01

    Unmanned aerial systems (UAS, also known as UAV, RPAS or drones) have a great potential to support a wide variety of aerial remote sensing applications. Most UAS work by acquiring data using on-board sensors for later post-processing. Some require the data gathered to be downlinked to the ground in real-time. However, depending on the volume of data and the cost of the communications, this later option is not sustainable in the long term. This paper develops the concept of virtualizing super-computation on-board UAS, as a method to ease the operation by facilitating the downlink of high-level information products instead of raw data. Exploiting recent developments in miniaturized multi-core devices is the way to speed-up on-board computation. This hardware shall satisfy size, power and weight constraints. Several technologies are appearing with promising results for high performance computing on unmanned platforms, such as the 36 cores of the TILE-Gx36 by Tilera (now EZchip) or the 64 cores of the Epiphany-IV by Adapteva. The strategy for virtualizing super-computation on-board includes the benchmarking for hardware selection, the software architecture and the communications aware design. A parallelization strategy is given for the 36-core TILE-Gx36 for a UAS in a fire mission or in similar target-detection applications. The results are obtained for payload image processing algorithms and determine in real-time the data snapshot to gather and transfer to ground according to the needs of the mission, the processing time, and consumed watts.

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

    Science.gov (United States)

    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. PMID:25379546

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

    Directory of Open Access Journals (Sweden)

    Chenlong Duan

    2014-01-01

    Full Text Available 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.

  12. Near-Field Characterization of a Printed Circuit Board in the Presence of a Finite-sized Metallic Ground Plane

    DEFF Research Database (Denmark)

    Franek, Ondrej; Sørensen, Morten; Ebert, Hans;

    2012-01-01

    Model of a generic printed circuit board (PCB) in a presence of a finite-sized metallic ground plane is introduced as a commonly occurring scenario of electronic module whose electromagnetic fields are disturbed by a nearby object. Finite-difference time-domain simulations are performed...

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

    Energy Technology Data Exchange (ETDEWEB)

    Nair, Aswathi; Raghunandan, Karthik; Yaswant, Vaddi; Sambandan, Sanjiv, E-mail: sanjiv@iap.iisc.ernet.in, E-mail: ssanjiv@isu.iisc.ernet.in [Department of Instrumentation and Applied Physics, Indian Institute of Science, Malleswaram, Bangalore 560012 (India); Pillai, Sreelal S. [Vikram Sarabhai Space Center, Indian Space Research Organization, Trivandrum 695022 (India)

    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.

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

    International Nuclear Information System (INIS)

    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

  15. Digitized adiabatic quantum computing with a superconducting circuit.

    Science.gov (United States)

    Barends, R; Shabani, A; Lamata, L; Kelly, J; Mezzacapo, A; Las Heras, U; Babbush, R; Fowler, A G; Campbell, B; Chen, Yu; Chen, Z; Chiaro, B; Dunsworth, A; Jeffrey, E; Lucero, E; Megrant, A; Mutus, J Y; Neeley, M; Neill, C; O'Malley, P J J; Quintana, C; Roushan, P; Sank, D; Vainsencher, A; Wenner, J; White, T C; Solano, E; Neven, H; Martinis, John M

    2016-06-01

    Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable. PMID:27279216

  16. Digitized adiabatic quantum computing with a superconducting circuit

    Science.gov (United States)

    Barends, R.; Shabani, A.; Lamata, L.; Kelly, J.; Mezzacapo, A.; Heras, U. Las; Babbush, R.; Fowler, A. G.; Campbell, B.; Chen, Yu; Chen, Z.; Chiaro, B.; Dunsworth, A.; Jeffrey, E.; Lucero, E.; Megrant, A.; Mutus, J. Y.; Neeley, M.; Neill, C.; O'Malley, P. J. J.; Quintana, C.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T. C.; Solano, E.; Neven, H.; Martinis, John M.

    2016-06-01

    Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable.

  17. Digitized adiabatic quantum computing with a superconducting circuit.

    Science.gov (United States)

    Barends, R; Shabani, A; Lamata, L; Kelly, J; Mezzacapo, A; Las Heras, U; Babbush, R; Fowler, A G; Campbell, B; Chen, Yu; Chen, Z; Chiaro, B; Dunsworth, A; Jeffrey, E; Lucero, E; Megrant, A; Mutus, J Y; Neeley, M; Neill, C; O'Malley, P J J; Quintana, C; Roushan, P; Sank, D; Vainsencher, A; Wenner, J; White, T C; Solano, E; Neven, H; Martinis, John M

    2016-06-08

    Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable.

  18. Integration of an X-Y prober with CAD driven database and test generation software for the testing of printed circuit boards

    OpenAIRE

    Goad, Kenneth G.

    1987-01-01

    Guided probe testing of printed circuit boards is a technique that has been well developed by automatic test equipment manufacturers to pinpoint faults. Though the guided probe technique of testing printed circuit boards is a process capable of providing high diagnostic resolution, the technique is inefficient when it is performed manually. The throughput of board testing is bottlenecked because of the time required for an operator to manually move a probe to a specific location ...

  19. Computer-aided design of large-scale integrated circuits - A concept

    Science.gov (United States)

    Schansman, T. T.

    1971-01-01

    Circuit design and mask development sequence are improved by using general purpose computer with interactive graphics capability establishing efficient two way communications link between design engineer and system. Interactive graphics capability places design engineer in direct control of circuit development.

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Petter, P.M.H., E-mail: patymhp@yahoo.com.br; 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cayumil, R. [Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052 (Australia); Khanna, R., E-mail: ritakhanna@unsw.edu.au [Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052 (Australia); Ikram-Ul-Haq, M.; Rajarao, R. [Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052 (Australia); Hill, A. [CSIRO Process Science and Engineering, Clayton, Melbourne, VIC 3168 (Australia); Sahajwalla, V. [Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052 (Australia)

    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

  3. Real-time monitoring system for improving corona electrostatic separation in the process of recovering waste printed circuit boards.

    Science.gov (United States)

    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. PMID:25395159

  4. On-board computational efficiency in real time UAV embedded terrain reconstruction

    Science.gov (United States)

    Partsinevelos, Panagiotis; Agadakos, Ioannis; Athanasiou, Vasilis; Papaefstathiou, Ioannis; Mertikas, Stylianos; Kyritsis, Sarantis; Tripolitsiotis, Achilles; Zervos, Panagiotis

    2014-05-01

    In the last few years, there is a surge of applications for object recognition, interpretation and mapping using unmanned aerial vehicles (UAV). Specifications in constructing those UAVs are highly diverse with contradictory characteristics including cost-efficiency, carrying weight, flight time, mapping precision, real time processing capabilities, etc. In this work, a hexacopter UAV is employed for near real time terrain mapping. The main challenge addressed is to retain a low cost flying platform with real time processing capabilities. The UAV weight limitation affecting the overall flight time, makes the selection of the on-board processing components particularly critical. On the other hand, surface reconstruction, as a computational demanding task, calls for a highly demanding processing unit on board. To merge these two contradicting aspects along with customized development, a System on a Chip (SoC) integrated circuit is proposed as a low-power, low-cost processor, which natively supports camera sensors and positioning and navigation systems. Modern SoCs, such as Omap3530 or Zynq, are classified as heterogeneous devices and provide a versatile platform, allowing access to both general purpose processors, such as the ARM11, as well as specialized processors, such as a digital signal processor and floating field-programmable gate array. A UAV equipped with the proposed embedded processors, allows on-board terrain reconstruction using stereo vision in near real time. Furthermore, according to the frame rate required, additional image processing may concurrently take place, such as image rectification andobject detection. Lastly, the onboard positioning and navigation (e.g., GNSS) chip may further improve the quality of the generated map. The resulting terrain maps are compared to ground truth geodetic measurements in order to access the accuracy limitations of the overall process. It is shown that with our proposed novel system,there is much potential in

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

    Science.gov (United States)

    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. PMID:18754380

  6. Effect of High-Humidity Testing on Material Parameters of Flexible Printed Circuit Board Materials

    Science.gov (United States)

    Lahokallio, Sanna; Saarinen, Kirsi; Frisk, Laura

    2013-09-01

    The tendency of polymers to absorb moisture impairs especially their electrical and mechanical properties. These are important characteristics for printed circuit board (PCB) materials, which should provide mechanical support as well as electrical insulation in many different environments in order to guarantee safe operation for electrical devices. Moreover, the effects of moisture are accelerated at increased temperatures. In this study, three flexible PCB dielectric materials, namely polyimide (PI), fluorinated ethylene-propylene (FEP), and polyethylene terephthalate (PET), were aged over different periods of time in a high-humidity test, in which the temperature was 85°C and relative humidity 85%. After aging, the changes in the structure of the polymers were studied by determining different material parameters such as modulus of elasticity, glass-transition temperature, melting point, coefficient of thermal expansion, water absorption, and crystallinity, and changes in the chemical structure with several techniques including thermomechanical analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy, moisture analysis, and a precision scale. The results showed that PI was extremely stable under the aging conditions and therefore an excellent choice for electrical applications under harsh conditions. Similarly, FEP proved to be relatively stable under the applied aging conditions. However, its crystallinity increased markedly during aging, and after 6000 h of aging the results indicated oxidation. PET suffered from hydrolysis during the test, leading to its embrittlement after 2000 h of aging.

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

    Science.gov (United States)

    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.

  8. Studies on the reuse of waste printed circuit board as an additive for cement mortar.

    Science.gov (United States)

    Ban, Bong-Chan; Song, Jong-Yoon; Lim, Joong-Yeon; Wang, Soo-Kyoon; An, Kwang-Guk; Kim, Dong-Su

    2005-01-01

    The recent development in electronic industries has generated a drastic increase in production of printed circuit boards (PCB). Accordingly, the amount of waste PCB from electronic productions and waste electronics and its environmental impact such as soil and groundwater contamination have become a great concern. This study aims to propose a method for reuse of waste PCB as an additive for cement mortar. Although the expansibility of waste PCB powder finer than 0.08 mm in water was observed to be greater than 2.0%, the maximum expansion rates in water for 0.08 to approximately 0.15 and 0.15 to approximately 0.30 mm sized PCB powders were less than 2.0%, which satisfied the necessary condition as an alternative additive for cement mortar in place of sand. The difference in the compressive strength of standard mortar and waste PCB added mortar was observed to be less than 10% and their difference was expected to be smaller after prolonged aging. The durability of waste PCB added cement mortar was also examined through dry/wet conditioning cyclic tests and acidic/alkaline conditioning tests. From the tests, both weight and compressive strength of cement mortar were observed to be recovered with aging. The leaching test for heavy metals from waste PCB added mortar showed that no heavy metal ions such as copper, lead, or cadmium were detected in the leachate, which resulted from fixation effect of the cement hydrates.

  9. Modelling, analysis, and acceleration of a printed circuit board fabrication process

    Indian Academy of Sciences (India)

    K S Aithal; Y Narahari; E Manjunath

    2001-10-01

    Product design and fabrication constitute an important business activity in any manufacturing firm. Designing an optimized product fabrication process is an important problem in itself and is of significant practical and research interest. In this paper, we look into a printed circuit board (PCB) fabrication process and investigate ways in which the fabrication cycle time can be minimized. Single class queueing networks constitute the modelling framework for our study. The model developed in this paper and the analysis experiments carried out are based on extensive data collected on a PCB fabrication company located in Bangalore, India. This is a representative PCB fabrication company involving multiple, concurrent fabrication works with contention for human/technical resources. Our model seeks to capture faithfully the flow of the fabrication process in this company and such other organisations, using queueing networks. Using the model developed, we explore how the cycle times can be reduced using input control, load balancing, and variability reduction. The model presented is sufficiently generic and conceptual; its scope extends beyond that of a PCB fabrication organization.

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

    Science.gov (United States)

    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. PMID:26022338

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. PMID:22677014

  13. Converting Non-Metallic Printed Circuit Boards Waste Into A Value Added Product

    Directory of Open Access Journals (Sweden)

    Shantha Kumari Muniyandi

    2013-05-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  16. Dissolution of brominated epoxy resins by dimethyl sulfoxide to separate waste printed circuit boards.

    Science.gov (United States)

    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. PMID:23398278

  17. A new technology for recycling materials from waste printed circuit boards.

    Science.gov (United States)

    Zhou, Yihui; Qiu, Keqiang

    2010-03-15

    Waste printed circuit boards (WPCBs) contain lots of valuable resources together with plenty of hazardous materials, which are considered both an attractive secondary resource and an environmental contaminant. In this research, a new process of "centrifugal separation+vacuum pyrolysis" for the combined recovery of solder and organic materials from WPCBs was investigated. The results of centrifugal separation indicated that the separation of solder from WPCBs was complete when WPCBs were heated at 240 degrees C, and the rotating drum was rotated at 1400 rpm for 6 min intermittently. The results of vacuum pyrolysis showed that the type-A of WPCBs without solder pyrolysed to form an average of 69.5 wt% residue, 27.8 wt% oil, and 2.7 wt% gas; and pyrolysis of the type-B of WPCBs without solder led to an average mass balance of 75.7 wt% residue, 20.0 wt% oil, and 4.3 wt% gas. The pyrolysis residues contain various metals, glass fibers and other inorganic materials, which could be recycled for further processing. The pyrolysis oils can be used for fuel or chemical feedstock and the pyrolysis gases can be collected and combusted for the pyrolysis self-sustain. This clean and non-polluting technology offers a new way to recycle valuable materials from WPCBs and prevent the environmental pollution of WPCBs effectively.

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

    Science.gov (United States)

    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. PMID:26196406

  19. Kinetic Study of the Pyrolysis of Waste Printed Circuit Boards Subject to Conventional and Microwave Heating

    Directory of Open Access Journals (Sweden)

    Chunyuan Ma

    2012-08-01

    Full Text Available This paper describes a kinetic study of the decomposition of waste printed circuit boards (WPCB under conventional and microwave-induced pyrolysis conditions. We discuss the heating rates and the influence of the pyrolysis on the thermal decomposition kinetics of WPCB. We find that the thermal degradation of WPCB in a controlled conventional thermogravimetric analyzer (TGA occurred in the temperature range of 300 °C–600 °C, where the main pyrolysis of organic matter takes place along with an expulsion of volumetric volatiles. The corresponding activation energy is decreased from 267 kJ/mol to 168 kJ/mol with increased heating rates from 20 °C/min to 50 °C/min. Similarly, the process of microwave-induced pyrolysis of WPCB material manifests in only one stage, judging by experiments with a microwave power of 700 W. Here, the activation energy is determined to be only 49 kJ/mol, much lower than that found in a conventional TGA subject to a similar heating rate. The low activation energy found in microwave-induced pyrolysis suggests that the adoption of microwave technology for the disposal of WPCB material and even for waste electronic and electrical equipment (WEEE could be an attractive option.

  20. Study on Metals Recovery from -0.074 mm Printed Circuit Boards by Enhanced Gravity Separation

    Institute of Scientific and Technical Information of China (English)

    赵跃民; 温雪峰; 施红霞; 焦红光; 陶有俊

    2006-01-01

    Nowadays study on reutilization of discarded printed circuit boards (PCBs) has great significance for achieving secondary resources recycling and preventing environmental pollution. Physical methods show great potential and advantages on discarded PCBs reutilization, compared with chemical and biological methods. However for the particles of -0.074 mm PCBs, little work has been done in the past because of lower separation efficiency and recovery. In this work, the conundrum of-0.074 mm PCBs reutilization was resolved successfully with the help of Falcon concentrator. Separation mechanism for fine particles with different mass densities in a Falcon centrifugal concentrator was analyzed. The main factors such as magnitude of rotation frequency (centrifugal acceleration), anti-charge water pressure and feeding concentration were studied,and interaction of different factors was analyzed using Design-Expert software. The experimental results show that metals grade of-0.074 mm PCBs and integration efficiency were obtained as 76.89% and 80.77% respectively when feeding concentration was 40 g/L with water pressure of 0.01 MPa and rotation frequency of 50 Hz.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2012-11-01

    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.

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

    Science.gov (United States)

    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.

  4. Synthesis of carbon nanotubes and porous carbons from printed circuit board waste pyrolysis oil

    International Nuclear Information System (INIS)

    The possibility and feasibility of using pyrolysis oil from printed circuit board (PCB) waste as a precursor for advanced carbonaceous materials is presented. The PCB waste was first pyrolyzed in a laboratory scale fixed bed reactor at 600 deg. C to prepare pyrolysis oil. The analysis of pyrolysis oil by gas chromatography-mass spectroscopy indicated that it contained a very high proportion of phenol and phenol derivatives. It was then polymerized in formaldehyde solution to synthesize pyrolysis oil-based resin which was used as a precursor to prepare carbon nanotubes (CNTs) and porous carbons. Scanning electron microscopy and transmission microscopy investigation showed that the resulting CNTs had hollow cores with outer diameter of ∼338 nm and wall thickness of ∼86 nm and most of them were filled with metal nanoparticles or nanorods. X-ray diffraction reveals that CNTs have an amorphous structure. Nitrogen adsorption isotherm analysis indicated the prepared porous carbons had a Brunauer-Emmett-Teller surface area of 1214 m2/g. The mechanism of the formation of the CNTs and porous carbons was discussed.

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

    International Nuclear Information System (INIS)

    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

  6. Copper recovery and gold enrichment from waste printed circuit boards by mediated electrochemical oxidation

    International Nuclear Information System (INIS)

    Highlights: • We developed a mediated electrochemical process for electronic waste treatment. • We achieved the simultaneous recovery of copper and gold enrichment. • Process scale up was realized based on the optimal values of operating parameters. • The waste does not require mechanical pretreatment in the scaled process. • The process proved to be efficient and eco-friendly as well. - Abstract: 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 (99.04 wt.%) at a current efficiency of 63.84% and specific energy consumption of 1.75 kW h/kg cooper. The gold concentration in the remained solid residue was 25 times higher than the gold concentration in the initial WPCB samples

  7. Thermal analysis of a part of circuit board card by the photothermal deflection technique

    Science.gov (United States)

    Dhouib, A.; Yacoubi, N.

    2014-09-01

    Photothermal deflection which is a non-destructive technique is widely used to study defects in materials. However, high spatial resolution and high sensitivity are required to detect them. To validate the theoretical model that we developed in the case, the sample is immersed in a paraffin oil-filled cell and heated with a laser beam of a diameter less than the dimensions of defects and of power 2 mW instead of several 100 mW power frequently used. Our model was tested on a part of a circuit board card having copper strips spaced periodically and embedded in the resin. The experimental curves of amplitude and phase variations according to displacement of the sample are in good agreement with the corresponding theoretical ones; and their coincidence permit us to deduce several parameters such as the width of the copper and resin strips, their thicknesses and their thermal properties. These comparisons allowed also to detect some anomalies in the structure such as inhomogeneity in the width, the shape and the thicknesses of copper and resins strips.

  8. Metals Recovery from Fine Printed Circuit Boards Using Falcon SB Concentrator

    Institute of Scientific and Technical Information of China (English)

    WEN Xue-feng; ZHAO Yue-min; PAN Yan-jun; HE Ya-qun; SONG Shu-lei; WANG Zhuo-ya

    2005-01-01

    Physical methods show great potential and advantages on comprehensive reutilization of waste printed circuit boards (PCBs) because of lower investment and operation cost, higher efficiency and environment friendliness. However, metals contained in fine fraction of PCBs cannot be recovered effectively by conventional equipments such as high tension electrostatic separator or shaking table. In the paper, this conundrum was resolved successfully with the enhanced Falcon SB concentrator. The separation mechanism of Falcon SB concentrator was analyzed and main factors affecting separation efficiency such as magnitude of rotation frequency of bowl, water counter pressure and slurry concentration of feed were studied and interaction of factors above also were investigated using Design-Expert software. Experiment results show that complete liberation degree and great difference of density between metals and nonmetals are suitable to recover metals from -74 μm PCBs using enhanced Falcon SB concentrator and 80.77 % integration efficiency can be achieved when slurry concentration of feed is 40 g/L with the water counter pressure of 0.01 MPa and rotation frequency of 50 Hz.

  9. Cell electroporation with a three-dimensional microelectrode array on a printed circuit board.

    Science.gov (United States)

    Xu, Youchun; Su, Shisheng; Zhou, Changcheng; Lu, Ying; Xing, Wanli

    2015-04-01

    Electroporation is a commonly used approach to rapidly introduce exogenous molecules into cells without permanent damage. Compared to classical electroporation protocols, microchip-based electroporation approaches have the advantages of high transfection efficiency and low consumption, but they also commonly rely on costly and tedious microfabrication technology. Hence, it is desirable to develop a novel, more affordable, and effective approach to facilitate cell electroporation. In this study, we utilized a standard printed circuit board (PCB) technology to fabricate a chip with an interdigitated array of electrodes for electroporation of suspended cells. The electrodes (thickness ~35 μm) fabricated by PCB technology are much thicker than the two-dimensional (2D) planar electrodes (thickness electroporation. HeLa, MCF7, COS7, Jurkat, and 3T3-L1 cells were efficiently transfected with the pEGFP-N1 plasmid using individually optimal electroporation parameters. This work provides a novel method for convenient and rapid cell transfection and thus holds promise for use as a low-cost disposable device in biomedical research.

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

    Science.gov (United States)

    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.

  11. Reconfigurable modular computer networks for spacecraft on-board processing

    Science.gov (United States)

    Rennels, D. A.

    1978-01-01

    The core electronics subsystems on unmanned spacecraft, which have been sent over the last 20 years to investigate the moon, Mars, Venus, and Mercury, have progressed through an evolution from simple fixed controllers and analog computers in the 1960's to general-purpose digital computers in current designs. This evolution is now moving in the direction of distributed computer networks. Current Voyager spacecraft already use three on-board computers. One is used to store commands and provide overall spacecraft management. Another is used for instrument control and telemetry collection, and the third computer is used for attitude control and scientific instrument pointing. An examination of the control logic in the instruments shows that, for many, it is cost-effective to replace the sequencing logic with a microcomputer. The Unified Data System architecture considered consists of a set of standard microcomputers connected by several redundant buses. A typical self-checking computer module will contain 23 RAMs, two microprocessors, one memory interface, three bus interfaces, and one core building block.

  12. Neuronal circuits and computations: pattern decorrelation in the olfactory bulb.

    Science.gov (United States)

    Friedrich, Rainer W; Wiechert, Martin T

    2014-08-01

    Neuronal circuits in the olfactory bulb transform odor-evoked activity patterns across the input channels, the olfactory glomeruli, into distributed activity patterns across the output neurons, the mitral cells. One computation associated with this transformation is a decorrelation of activity patterns representing similar odors. Such a decorrelation has various benefits for the classification and storage of information by associative networks in higher brain areas. Experimental results from adult zebrafish show that pattern decorrelation involves a redistribution of activity across the population of mitral cells. These observations imply that pattern decorrelation cannot be explained by a global scaling mechanism but that it depends on interactions between distinct subsets of neurons in the network. This article reviews insights into the network mechanism underlying pattern decorrelation and discusses recent results that link pattern decorrelation in the olfactory bulb to odor discrimination behavior.

  13. Using Mathematical Morphology to Detect the Imperfections of the Printed Circuit Boards

    Directory of Open Access Journals (Sweden)

    Ionut Balan

    2008-01-01

    Full Text Available Image processing is a form of signal processing(analysis, interpretation, and manipulation of signals forwhich the input is an image, such as photographs; the outputof image processing can be either an image or a set ofcharacteristics or parameters related to the image. Typicaloperations of image processing are geometrictransformations such as enlargement, reduction androtation, color corrections such as brightness and contrastadjustments, quantization, or conversion to a different colorspace, interpolation and recovery of a full image from a rawimage format, image editing, image differencing, imagestabilization, image segmentation and other. Applications ofthese operations are encountered in computer vision, facedetection, feature detection, medical image processing,microscope image processing, morphological imageprocessing, remote sensing and many other disciplines.Morphological image processing is a collection of techniquesfor digital image processing based on mathematicalmorphology. By combining these morphological operatorswe can obtain algorithms for many image processing tasks,such as feature detection, image segmentation, imagesharpening, image filtering, and granulometry. Likewise,using this technology we can detect some imperfections of theprinted circuits, imperfections that allow us to repair it,opportunely. So in this way, we can eliminate some costs inthe technological process.The paper presents an introduction in mathematicalmorphology, describes “hit and miss transform”, dilationand erosion and, after all, we present the usage of two ofthese operations in printed circuit error detection.

  14. Development of printed-circuit-board based industry-compatible point-of-care biosensing and bioprocessing technology with applications

    OpenAIRE

    Tseng, Hsiu-Yang

    2015-01-01

    This thesis presents the development of a technology employing printed circuit board (PCB) technology to facilitate the performance and translation of point-of-care (POC) biosensing and bioprocessing devices toward practical products. Key features of the proposed technology are a universal, standardized platform and a set of techniques, featuring integrated functional units, three-dimensional (3D) configurations, convenient device-instrumentation interconnections, and industry-compatible prec...

  15. Estimation of Relative Permittivity of Printed Circuit Board with Fiber Glass Epoxy as Dielectric for UHF Applications

    OpenAIRE

    Ronal D. Montoya-Montoya; Natalia Gaviria-Gómez

    2013-01-01

    This paper presents the results of measuring relative permittivity of fiber glass printed circuit board (PCB’s), using a rectangular resonant cavity. The relative permittivity is presented as function of frequency. To obtain resonant frequencies, the return loss was measured using a network analyzer. Relative permittivity was calculated by finding frequencies of resonant cavity modes. The results are presented in a frequency span of 1 to 3.5GHz. It was clearly shown the nonlinear behavior of ...

  16. The effect of shredding and particle size in physical and chemical processing of printed circuit boards waste

    OpenAIRE

    Oliveira, Paula C.; Taborda, F. Charters; Nogueira, C. A.; Margarido, F.

    2011-01-01

    Circuit boards present in most electric and electronic devices are very important components, which should be removed during sorting and dismantling operations in order to allow further adequate treatment for recovering valuable metals such as copper, nickel, zinc, lead, tin and rare elements. This recovery can be made by physical and chemical processes being size reduction by shredding the first step. In this paper, the effect of particle size in physical and chemical processing of printed c...

  17. 印制板技术的最近动向%New technology trend of Printed Circuit Board

    Institute of Scientific and Technical Information of China (English)

    蔡积庆(译)

    2014-01-01

    This paper describes the new technology trend of printed circuit boards including high density trend of PCB, electronic characteristics of PCB, construction and process of PCB, and technology development in build-up process.%概述了最近的PCB技术动向,包括PCB的高密度化趋势,PCB的电气特性,PCB的构造和工艺以及积层法中的技术开发。

  18. A NEW CONTROL CIRCUIT AND COMPUTER SOFTWARE FOR CONTROLING PHOTOVOLTAIC SYSTEMS

    OpenAIRE

    Mustafa Berkant SELEK; İŞLER, Yalçın; Metin ÇOLAK

    2008-01-01

    In this study, a new microcontroller circuit was designed and new computer software was implemented to control power flow currents of renewable energy system, which is established in Solar Energy Institute, Ege University, Bornova, Izmir, Turkey. PIC18F452 microcontroller based electronic circuit was designed to control another electronic circuit that includes power electronic switching components. Readily available standard control circuits are designed for switching single level inverters. ...

  19. Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace

    International Nuclear Information System (INIS)

    Highlights: ► 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. ► 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 Br2. ► Temperature has crucial influence over the inhibition of HBr conversion to Br2, 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 Br2/HBr in flue gas greatly. ► 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 Br2) 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 (RTHT) was set at 0.25, 0.5, or 0.75 s. Combustion efficiency depends on temperature, EAF and RTHT; temperature has the most significant effect. Conversion of organic bromine from flame retardants into HBr and Br2 depends on temperature and EAF. Temperature has crucial influence over the ratio of HBr to Br2

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

    Science.gov (United States)

    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. PMID:19121892

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

    Science.gov (United States)

    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.

  2. Leaching characteristics of heavy metals and brominated flame retardants from waste printed circuit boards

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiaoyu [State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237 (China); Guo, Jie, E-mail: guojie@ecust.edu.cn [State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237 (China); Lin, Kuangfei [State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237 (China); Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai 200237 (China); Huang, Kai; Deng, Jingjing [State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai 200237 (China)

    2013-02-15

    Highlights: ► Cu and Pb were the most leachable heavy metals in WPCBs according to TCLP and SPLP. ► Penta-BDE congeners were dominated in all extracts. ► High dissolved organic matter condition promoted the BFRs leaching rate. ► Leaching from WPCBs was a significant emission source of BFRs in landfill. -- Abstract: Leaching assessment on five heavy metals (copper, zinc, lead, nickel and cadmium) and two brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA), from waste printed circuit boards (WPCBs) were conducted using various leaching methods. The mean leaching concentrations of copper were the highest in both toxicity characteristic leaching procedures (TCLP) and synthetic precipitation leaching procedures (SPLP) tests at 8.6 mg/L and 1.1 mg/L, while only lead (6.2 mg/L) exceeded the TCLP criteria and Chinese EPA regulatory limit (both 5.0 mg/L). However, PBDEs and TBBPA were not detected in TCLP and SPLP tests. Then the BFRs leaching trends and potential leachabilities were further investigated in actual landfill leachates using a modified method. Leaching characteristics that fast-leaching initially followed by slow-desorption over time were generally observed. In landfill leachate tests, the highest leaching concentrations of PBDEs and TBBPA were determined at 30.39 and 12.27 μg/L. Meanwhile, the highest leaching rates were estimated to reach 0.08% and 1.00%, respectively, which were significantly influenced by the dissolved organic carbon contents of extracts, the hydrophobicities of target BFRs and the specific surface areas of WPCBs materials. These results proved that leaching from WPCBs was a significant emission source of BFRs in landfill and electronic waste recycling dumpsite.

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

    International Nuclear Information System (INIS)

    Highlights: ► Material recovery driven by composition, choice of ranking, and weighting. ► Economic potential for new recycling technologies quantified for several metrics. ► Indicators developed for materials incurring high eco-toxicity costs. ► 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.

  4. Metals recovering from waste printed circuit boards (WPCBs) using molten salts

    International Nuclear Information System (INIS)

    Highlights: ► Recovering of valuable metals from WPCBs. ► Low temperature treatment, i.e., 300 °C. ► Copper, and precious metals are recovered, without dissolution or melting. ► Many hazardous gases are dissolved and trapped in the molten salt. ► Under operation without oxygen the flue gas contains large quantities of hydrogen. - Abstract: 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 . 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.

  5. Leaching characteristics of heavy metals and brominated flame retardants from waste printed circuit boards

    International Nuclear Information System (INIS)

    Highlights: ► Cu and Pb were the most leachable heavy metals in WPCBs according to TCLP and SPLP. ► Penta-BDE congeners were dominated in all extracts. ► High dissolved organic matter condition promoted the BFRs leaching rate. ► Leaching from WPCBs was a significant emission source of BFRs in landfill. -- Abstract: Leaching assessment on five heavy metals (copper, zinc, lead, nickel and cadmium) and two brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA), from waste printed circuit boards (WPCBs) were conducted using various leaching methods. The mean leaching concentrations of copper were the highest in both toxicity characteristic leaching procedures (TCLP) and synthetic precipitation leaching procedures (SPLP) tests at 8.6 mg/L and 1.1 mg/L, while only lead (6.2 mg/L) exceeded the TCLP criteria and Chinese EPA regulatory limit (both 5.0 mg/L). However, PBDEs and TBBPA were not detected in TCLP and SPLP tests. Then the BFRs leaching trends and potential leachabilities were further investigated in actual landfill leachates using a modified method. Leaching characteristics that fast-leaching initially followed by slow-desorption over time were generally observed. In landfill leachate tests, the highest leaching concentrations of PBDEs and TBBPA were determined at 30.39 and 12.27 μg/L. Meanwhile, the highest leaching rates were estimated to reach 0.08% and 1.00%, respectively, which were significantly influenced by the dissolved organic carbon contents of extracts, the hydrophobicities of target BFRs and the specific surface areas of WPCBs materials. These results proved that leaching from WPCBs was a significant emission source of BFRs in landfill and electronic waste recycling dumpsite

  6. Using vacuum pyrolysis and mechanical processing for recycling waste printed circuit boards

    International Nuclear Information System (INIS)

    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 deg. C for 10 min. This study had demonstrated the feasibility of vacuum pyrolysis and mechanical processing for recycling WPCB.

  7. 47 CFR 15.102 - CPU boards and power supplies used in personal computers.

    Science.gov (United States)

    2010-10-01

    ... computers. 15.102 Section 15.102 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Unintentional Radiators § 15.102 CPU boards and power supplies used in personal computers. (a... modifications that must be made to a personal computer, peripheral device, CPU board or power supply...

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

    International Nuclear Information System (INIS)

    Highlights: ► The disassembly of electric/electronic components (EECs) layered in PCB as the first-step in recycling process. ► The disassembling treatment was carried out by the new designed apparatus. ► Most of the EECs (over 95%) can be recovered in a nondestructive state. ► These EECs contain 17 groups and can be classified into 54 types based on their shapes and sizes. ► The successive 3 stages of physical separation would enables the recovery of minor ingredients. - Abstract: 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 (Earea) and the weight ratio of the detached EECs (Eweight). In the disassembly treatment, these efficiencies were improved with an increase of grinder speed and grinder height. 97.7% (Earea) and 98% (Eweight) could be accomplished ultimately by 3 repetitive treatments at a grinder speed of 5500 rpm and a grinder height of 1.5 mm. 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

  9. Recycling of non-metallic fractions from waste printed circuit boards: A review

    International Nuclear Information System (INIS)

    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 70 wt% 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

  10. How to design and establish a computer bulletin board to support inventors

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    This booklet is a ``how-to handbook`` to demonstrate the development of an interactive electronic bulletin board as a support network for independent inventors and small business inventors. This will explain step-by-step, how Linking Alaskan Minds{trademark}, the Alaskan model of an interactive computer bulletin board system, was developed and designed to serve as a successfully working, interactive computer bulletin board that links and supports independent inventors in Alaska.

  11. How to design and establish a computer bulletin board to support inventors

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    This booklet is a how-to handbook'' to demonstrate the development of an interactive electronic bulletin board as a support network for independent inventors and small business inventors. This will explain step-by-step, how Linking Alaskan Minds{trademark}, the Alaskan model of an interactive computer bulletin board system, was developed and designed to serve as a successfully working, interactive computer bulletin board that links and supports independent inventors in Alaska.

  12. OptCircuit: An optimization based method for computational design of genetic circuits

    OpenAIRE

    Maranas Costas D; Dasika Madhukar S

    2008-01-01

    Abstract Background Recent years has witnessed an increasing number of studies on constructing simple synthetic genetic circuits that exhibit desired properties such as oscillatory behavior, inducer specific activation/repression, etc. It has been widely acknowledged that that task of building circuits to meet multiple inducer-specific requirements is a challenging one. This is because of the incomplete description of component interactions compounded by the fact that the number of ways in wh...

  13. Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Palmieri, Roberta; Bonifazi, Giuseppe; Serranti, Silvia, E-mail: silvia.serranti@uniroma1.it

    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.

  14. Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging

    International Nuclear Information System (INIS)

    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

  15. Effect of solder flux residue on the performance of silicone conformal coatings on printed circuit board assemblies

    DEFF Research Database (Denmark)

    Rathinavelu, Umadevi; Jellesen, Morten Stendahl; Ambat, Rajan

    2013-01-01

    Conformal coatings are applied on printed circuit board assemblies (PCBAs) in order to protect the assembly from environmental influence and silicone-based coating is commonly used. A systematic study on the performance of silicone conformal coating in connection with process-related contaminants...... across the components, morphology of the coating, and analysis of dendrite formation due to electrochemical migration under the coating. The morphology of the coating before and after exposure was investigated using scanning electron microscopy, and energy dispersive X-ray spectroscopy. Results show...

  16. Estimation of Relative Permittivity of Printed Circuit Board with Fiber Glass Epoxy as Dielectric for UHF Applications

    Directory of Open Access Journals (Sweden)

    Ronal D. Montoya-Montoya

    2013-11-01

    Full Text Available This paper presents the results of measuring relative permittivity of fiber glass printed circuit board (PCB’s, using a rectangular resonant cavity. The relative permittivity is presented as function of frequency. To obtain resonant frequencies, the return loss was measured using a network analyzer. Relative permittivity was calculated by finding frequencies of resonant cavity modes. The results are presented in a frequency span of 1 to 3.5GHz. It was clearly shown the nonlinear behavior of the relative permittivity for the dielectric laminate evaluated, even what happens respect to the frequency of the resonant modes below and above to frequency of 2 GHz.

  17. Computer science: Nanoscale connections for brain-like circuits

    Science.gov (United States)

    Legenstein, Robert

    2015-05-01

    Tiny circuit elements called memristors have been used as connections in an artificial neural network - enabling the system to learn to recognize letters of the alphabet from imperfect images. See Letter p.61

  18. An Autonomous Underwater Recorder Based on a Single Board Computer.

    Science.gov (United States)

    Caldas-Morgan, Manuel; Alvarez-Rosario, Alexander; Rodrigues Padovese, Linilson

    2015-01-01

    As industrial activities continue to grow on the Brazilian coast, underwater sound measurements are becoming of great scientific importance as they are essential to evaluate the impact of these activities on local ecosystems. In this context, the use of commercial underwater recorders is not always the most feasible alternative, due to their high cost and lack of flexibility. Design and construction of more affordable alternatives from scratch can become complex because it requires profound knowledge in areas such as electronics and low-level programming. With the aim of providing a solution; a well succeeded model of a highly flexible, low-cost alternative to commercial recorders was built based on a Raspberry Pi single board computer. A properly working prototype was assembled and it demonstrated adequate performance levels in all tested situations. The prototype was equipped with a power management module which was thoroughly evaluated. It is estimated that it will allow for great battery savings on long-term scheduled recordings. The underwater recording device was successfully deployed at selected locations along the Brazilian coast, where it adequately recorded animal and manmade acoustic events, among others. Although power consumption may not be as efficient as that of commercial and/or micro-processed solutions, the advantage offered by the proposed device is its high customizability, lower development time and inherently, its cost. PMID:26076479

  19. An Autonomous Underwater Recorder Based on a Single Board Computer.

    Science.gov (United States)

    Caldas-Morgan, Manuel; Alvarez-Rosario, Alexander; Rodrigues Padovese, Linilson

    2015-01-01

    As industrial activities continue to grow on the Brazilian coast, underwater sound measurements are becoming of great scientific importance as they are essential to evaluate the impact of these activities on local ecosystems. In this context, the use of commercial underwater recorders is not always the most feasible alternative, due to their high cost and lack of flexibility. Design and construction of more affordable alternatives from scratch can become complex because it requires profound knowledge in areas such as electronics and low-level programming. With the aim of providing a solution; a well succeeded model of a highly flexible, low-cost alternative to commercial recorders was built based on a Raspberry Pi single board computer. A properly working prototype was assembled and it demonstrated adequate performance levels in all tested situations. The prototype was equipped with a power management module which was thoroughly evaluated. It is estimated that it will allow for great battery savings on long-term scheduled recordings. The underwater recording device was successfully deployed at selected locations along the Brazilian coast, where it adequately recorded animal and manmade acoustic events, among others. Although power consumption may not be as efficient as that of commercial and/or micro-processed solutions, the advantage offered by the proposed device is its high customizability, lower development time and inherently, its cost.

  20. An Autonomous Underwater Recorder Based on a Single Board Computer.

    Directory of Open Access Journals (Sweden)

    Manuel Caldas-Morgan

    Full Text Available As industrial activities continue to grow on the Brazilian coast, underwater sound measurements are becoming of great scientific importance as they are essential to evaluate the impact of these activities on local ecosystems. In this context, the use of commercial underwater recorders is not always the most feasible alternative, due to their high cost and lack of flexibility. Design and construction of more affordable alternatives from scratch can become complex because it requires profound knowledge in areas such as electronics and low-level programming. With the aim of providing a solution; a well succeeded model of a highly flexible, low-cost alternative to commercial recorders was built based on a Raspberry Pi single board computer. A properly working prototype was assembled and it demonstrated adequate performance levels in all tested situations. The prototype was equipped with a power management module which was thoroughly evaluated. It is estimated that it will allow for great battery savings on long-term scheduled recordings. The underwater recording device was successfully deployed at selected locations along the Brazilian coast, where it adequately recorded animal and manmade acoustic events, among others. Although power consumption may not be as efficient as that of commercial and/or micro-processed solutions, the advantage offered by the proposed device is its high customizability, lower development time and inherently, its cost.

  1. Locks and raspberries: a comparative study of single-board computers for access control

    OpenAIRE

    Romin, Andreas

    2016-01-01

    Over the past decade, there has been a drastic development of the single-board computer market. These computers are now in a position where they can compete with classic embedded hardware. Such fast improvement has led ASSA ABLOY, a well-known lock and security company, to see value in replacing some of their existing access control hardware with an off-the-shelf single-board computer. Therefore, a comparative study of single-board computers was performed for this company. Some of the compare...

  2. CIRCUS--A digital computer program for transient analysis of electronic circuits

    Science.gov (United States)

    Moore, W. T.; Steinbert, L. L.

    1968-01-01

    Computer program simulates the time domain response of an electronic circuit to an arbitrary forcing function. CIRCUS uses a charge-control parameter model to represent each semiconductor device. Given the primary photocurrent, the transient behavior of a circuit in a radiation environment is determined.

  3. State-variable analysis of non-linear circuits with a desk computer

    Science.gov (United States)

    Cohen, E.

    1981-01-01

    State variable analysis was used to analyze the transient performance of non-linear circuits on a desk top computer. The non-linearities considered were not restricted to any circuit element. All that is required for analysis is the relationship defining each non-linearity be known in terms of points on a curve.

  4. Computing Symmetric Boolean Functions by Circuits with Few Exact Threshold Gates

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt

    2007-01-01

    We consider constant depth circuits augmented with few exact threshold gates with arbitrary weights. We prove strong (up to exponential) size lower bounds for such circuits computing symmetric Boolean functions. Our lower bound is expressed in terms of a natural parameter, the balance, of symmetr...

  5. Development of Three-Ring Conductance Meter on Flexible Printed Circuit Board for Liquid Film Thickness Measurement

    International Nuclear Information System (INIS)

    Electrical methods which based on conductance of fluid film have been widely applied for many years. Recently, Damsohn developed a high speed liquid film sensor that has great time and spatial resolution by applying printed circuit board (PCB) and wire-mesh signal processing unit. However, the conductivity of the fluid can be affected by its temperature change and previous electrical methods have limitations of its applicability where a heat transfer is involved. In order to overcome this limitation, Kim proposed three-ring conductance method which can measure the liquid film thickness independent of the liquid temperature variation. In the present work, the three-ring conductance meter is improved by fabricating it on flexible printed circuit board (FPCB). Since the FPCB can be attached on a curved surface and can tolerate temperature up to 180 .deg. C, it is expected to be applied to more diverse experimental conditions of nuclear thermal-hydraulics. This paper introduces the three ring conductance meter on FPCB and a preliminary experimental result in order to show its feasibility for measuring liquid film thickness under temperature varying conditions. From this experimental research, the availability of three-ring conductance meter fabricated on FPCB for measuring film-thickness by using current output signal was proved. Besides, the necessity of customized electrode design depending on film-thickness was found. Also, it was confirmed that the manufactured three-ring conductance meter can measure the film-thickness regardless of temperature change

  6. Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging.

    Science.gov (United States)

    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.

  7. Collaborative strategic board games as a site for distributed computational thinking

    OpenAIRE

    Berland, Matthew; Lee, Victor R.

    2011-01-01

    This paper examines the idea that contemporary strategic board games represent an informal, interactional context in which complex computational thinking takes place. When games are collaborative – that is, a game requires that players work in joint pursuit of a shared goal – the computational thinking is easily observed as distributed across several participants. This raises the possibility that a focus on such board games are profitable for those who wish to understand computational thinkin...

  8. Superior model for fault tolerance computation in designing nano-sized circuit systems

    Energy Technology Data Exchange (ETDEWEB)

    Singh, N. S. S., E-mail: narinderjit@petronas.com.my; Muthuvalu, M. S., E-mail: msmuthuvalu@gmail.com [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak (Malaysia); Asirvadam, V. S., E-mail: vijanth-sagayan@petronas.com.my [Electrical and Electronics Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak (Malaysia)

    2014-10-24

    As CMOS technology scales nano-metrically, reliability turns out to be a decisive subject in the design methodology of nano-sized circuit systems. As a result, several computational approaches have been developed to compute and evaluate reliability of desired nano-electronic circuits. The process of computing reliability becomes very troublesome and time consuming as the computational complexity build ups with the desired circuit size. Therefore, being able to measure reliability instantly and superiorly is fast becoming necessary in designing modern logic integrated circuits. For this purpose, the paper firstly looks into the development of an automated reliability evaluation tool based on the generalization of Probabilistic Gate Model (PGM) and Boolean Difference-based Error Calculator (BDEC) models. The Matlab-based tool allows users to significantly speed-up the task of reliability analysis for very large number of nano-electronic circuits. Secondly, by using the developed automated tool, the paper explores into a comparative study involving reliability computation and evaluation by PGM and, BDEC models for different implementations of same functionality circuits. Based on the reliability analysis, BDEC gives exact and transparent reliability measures, but as the complexity of the same functionality circuits with respect to gate error increases, reliability measure by BDEC tends to be lower than the reliability measure by PGM. The lesser reliability measure by BDEC is well explained in this paper using distribution of different signal input patterns overtime for same functionality circuits. Simulation results conclude that the reliability measure by BDEC depends not only on faulty gates but it also depends on circuit topology, probability of input signals being one or zero and also probability of error on signal lines.

  9. Superior model for fault tolerance computation in designing nano-sized circuit systems

    International Nuclear Information System (INIS)

    As CMOS technology scales nano-metrically, reliability turns out to be a decisive subject in the design methodology of nano-sized circuit systems. As a result, several computational approaches have been developed to compute and evaluate reliability of desired nano-electronic circuits. The process of computing reliability becomes very troublesome and time consuming as the computational complexity build ups with the desired circuit size. Therefore, being able to measure reliability instantly and superiorly is fast becoming necessary in designing modern logic integrated circuits. For this purpose, the paper firstly looks into the development of an automated reliability evaluation tool based on the generalization of Probabilistic Gate Model (PGM) and Boolean Difference-based Error Calculator (BDEC) models. The Matlab-based tool allows users to significantly speed-up the task of reliability analysis for very large number of nano-electronic circuits. Secondly, by using the developed automated tool, the paper explores into a comparative study involving reliability computation and evaluation by PGM and, BDEC models for different implementations of same functionality circuits. Based on the reliability analysis, BDEC gives exact and transparent reliability measures, but as the complexity of the same functionality circuits with respect to gate error increases, reliability measure by BDEC tends to be lower than the reliability measure by PGM. The lesser reliability measure by BDEC is well explained in this paper using distribution of different signal input patterns overtime for same functionality circuits. Simulation results conclude that the reliability measure by BDEC depends not only on faulty gates but it also depends on circuit topology, probability of input signals being one or zero and also probability of error on signal lines

  10. High speed bending of 2nd level interconnects on printed circuit boards for automotive electronics

    NARCIS (Netherlands)

    Kouters, M.H.M.; Ubachs, R.; Wiel, H.J. van de; Waal, A. van der; Veer, J. van der

    2011-01-01

    Standard drop tests for portable electronics are not representative for the qualification of automotive electronics. High-frequency vibrations are more dominant than abrupt shocks during normal operation. In this work a high speed board bending (HSB) method is developed to mimic the constant cyclic

  11. Rotational artifacts in on-board cone beam computed tomography

    International Nuclear Information System (INIS)

    Rotational artifacts in image guidance systems lead to registration errors that affect non-isocentric treatments and dose to off-axis organs-at-risk. This study investigates a rotational artifact in the images acquired with the on-board cone beam computed tomography system XVI (Elekta, Stockholm, Sweden). The goals of the study are to identify the cause of the artifact, to characterize its dependence on other quantities, and to investigate possible solutions. A 30 cm diameter cylindrical phantom is used to acquire clockwise and counterclockwise scans at five speeds (120 to 360 deg min−1) on six Elekta linear accelerators from three generations (MLCi, MLCi2 and Agility). Additional scans are acquired with different pulse widths and focal spot sizes for the same mAs. Image quality is evaluated using a common phantom with an in-house three dimensional contrast transfer function attachment. A robust, operator-independent analysis is developed which quantifies rotational artifacts with 0.02° accuracy and imaging system delays with 3 ms accuracy. Results show that the artifact is caused by mislabelling of the projections with a lagging angle due to various imaging system delays. For the most clinically used scan speed (360 deg min−1), the artifact is ∼0.5°, which corresponds to ∼0.25° error per scan direction with the standard Elekta procedure for angle calibration. This leads to a 0.5 mm registration error at 11 cm off-center. The artifact increases linearly with scan speed, indicating that the system delay is independent of scan speed. For the most commonly used pulse width of 40 ms, this delay is 34 ± 1 ms, part of which is half the pulse width. Results are consistent among the three linac generations. A software solution that corrects the angles of individual projections is shown to eliminate the rotational error for all scan speeds and directions. Until such a solution is available from the manufacturer, three clinical solutions are

  12. Report of the Computer Study Committee; Submitted to the Board of Regents, State of Kansas.

    Science.gov (United States)

    Kansas State Board of Regents, Topeka.

    The Computer Study Committee was formed under the Board of Regents in Kansas to determine the presence and use of computers in the seven state institutions. To collect data, the Committee sent out questionnaires, made campus visits and conducted interviews. The bulk of the report discusses (1) funding and accounting procedures for computer use and…

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

    Energy Technology Data Exchange (ETDEWEB)

    Troeger, K., E-mail: altstaedt@uni-bayreuth.de; Darka, R. Khanpour, E-mail: altstaedt@uni-bayreuth.de; Neumeyer, T., E-mail: altstaedt@uni-bayreuth.de; Altstaedt, V., E-mail: altstaedt@uni-bayreuth.de [Polymer Engineering, University of Bayreuth, Germany and Polymer Engineering, Universitaetsstrasse 30, 95447 Bayreuth (Germany)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, S. S.; Zhuang, G.; Zhang, M.; Xia, D. H.; Rao, B.; Zhang, X. Q.; Pan, Y. [College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Gentle, K. [Institute of Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

    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.

  15. New printed circuit boards magnetic coils in the vacuum vessel of J-TEXT tokamak for position measurementa)

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. PMID:20518505

  17. New technology for separating resin powder and fiberglass powder from fiberglass-resin powder of waste printed circuit boards.

    Science.gov (United States)

    Li, Jia; Gao, Bei; Xu, Zhenming

    2014-05-01

    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. PMID:24678800

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

    International Nuclear Information System (INIS)

    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.

  19. Influence of incorporation of powder of printed circuit boards on technological properties and microstructure of triaxial ceramics

    International Nuclear Information System (INIS)

    Using the methodology of experiments with mixtures, seven formulations of clay, phyllite, and printed circuit boards (PCB) were obtained to study the influence of this waste on triaxial ceramic tiles. Each formulation was processed under conditions similar to those used in the ceramic tiles industry, and characterized for fired modulus of rupture (FMoR) and water absorption (WA). The samples sintered at 1180°C were also subjected to analysis by XRD and SEM. The lowest resistance was observed in samples with 40% residue, while the highest strength occurred for samples with 14% residue, which reached average values of mechanical strength and water absorption of 35.0 MPa and 2.0%, respectively. The microstructure showed that it is possible to use waste of PCB in triaxial ceramic, which exhibits a fluxing behavior and it has an important effect on the sinterability and the development of appropriate microstructures. (author)

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

    International Nuclear Information System (INIS)

    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

  1. Fabric circuit board-based dry electrode and its characteristics for long-term physiological signal recording.

    Science.gov (United States)

    Yoo, Jerald; Yoo, Hoi-Jun

    2011-01-01

    This paper presents a dry fabric electrode and its characteristics. For long-term physiological signal monitoring, conventional wet type electrode such as an Ag/AgCl electrode may not be sufficient, because captured signal strength degrades over time as its electrolyte dehydrates. Moreover, the electrolyte may cause skin irritation over a period of time. As a complement, a dry electrode can be used. In this work, fabric-based dry electrodes are introduced. Planar-Fabric Circuit Board (P-FCB) technology enables low cost and uniform productions of such electrodes; electrical properties of the electrodes with various materials, sizes, and time are shown. Both the strengths and drawbacks of the fabric-based electrodes are also discussed.

  2. Characterization of copper surfaces used in electronic circuit boards by reflectance FT-IR[Fouier Transform - Infrared

    Energy Technology Data Exchange (ETDEWEB)

    Sloan, J.M.; Pergantis, C.G.

    2000-07-01

    Organic and organo-metallic coatings are presently being applied over bare copper as an approach to improve the co-planarity of circuit boards. Conformal organic solderability preservative coatings (OSP) are environmentally and economically advantageous over the more commonly used lead based coatings. Problems arise in assessing the solderability of the bare copper and the integrity of the organic coating. Specular reflectance Fourier transform infrared spectroscopy (FT-IR) was utilized to monitor and evaluate the formation of Cu oxides occurring on copper substrates used in the manufacturing of electronic circuit boards. Previous studies reported the utility of this technique. By measuring the oxide and protective coating characteristics of these surfaces, their solderability performance can rapidly be evaluated in a manufacturing environment. OSP coated test specimens were subjected to hot-dry and hot-wet environmental conditions using MIL-STD-202F and MIL-STD-883E as guides. The resultant FT-IR spectra provided clear evidence for the formation of various Cu oxides at the Cu/OSP interface over exposure time, for the samples subjected to the hot-dry environment. IR spectral bands consistent with O-Cu-O and Cu{sub 2}O{sub 2} formation appear, while very minimal deterioration to the OSP coating was observed. The appearance of the Cu oxide layers grew steadily with increased environmental exposure. Specimens subjected to the hot-wet conditions showed no significant signs of deterioration. The IR data can be directly correlated to solderability performance as evaluated by wet balance testing.

  3. Design and Fabrication of Liquid Film Sensor Using Flexible Printed Circuit Board Based on Three-Ring Conductance Meter

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyu-Byung; Park, Goon-Cherl; Cho, Hyoung Kyu [Seoul National University, Seoul (Korea, Republic of); Kim, Jong-Rok; Euh, Dong-Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In this study, the three-ring conductance meter is fabricated on FPCB. The FPCB can tolerate relatively high temperature (400K). And thanks to the high flexibility, it has applicability on a curved surface. This paper introduces the design procedure of liquid film sensor and calibration result in order to confirm its feasibility. Through the electrical potential analysis, liquid film sensor was designed. Two-phase flow is frequent phenomena in some industrial environments. Especially gas-liquid flow is common in nuclear industry, understanding the two-phase flow is an important part of the analysis on safety and performance of nuclear safety system. As the liquid film thickness is one of key factors, a lot of research has been conducted for measuring liquid film thickness. Recently, electrical methods have been widely applied for many years. Damsohn developed a high speed liquid film sensor that has high resolution for time and space by combining conductance method with wire-mesh signal processing unit. However, since the electric conductivity of liquid can be affected by its temperature, the conventional electrical conductance methods have limitation on applying for varying temperature conditions where a heat transfer is involved. Coney proposed three-ring conductance method that can compensate the change of conductivity of the liquid. Kim and Lee showed the feasibility of the three-ring conductance meter by fabricating it on printed circuit board (PCB) and flexible printed circuit board (FPCB) individually. Calibration procedure was conducted with the manufactured film sensor. By the result of calibration result, it was confirmed that this sensor can measure the film thickness up to 3 mm. In addition to this calibration, study on sensitivity of the sensor and optimum signal processing are needed for applying in dynamic measurement of various two-phase flow experiment.

  4. A quick solution, made to measure; Big scientific experiments need big circuit boards and that's where East Kilbride's D-TACQ comes in

    CERN Document Server

    Gardner, D

    2003-01-01

    D-TACQ is a small electronics company operating in a highly-specialised market with technological expertise that few can match worldwide. It specialises in designing and manufacturing bespoke printed circuit boards (PCBs) which handle data acquisition tasks linked to scientific instrumentation and control systems (1 page).

  5. Integrated mechanisms of anticipation and rate-of-change computations in cortical circuits.

    Directory of Open Access Journals (Sweden)

    Gabriel D Puccini

    2007-05-01

    Full Text Available Local neocortical circuits are characterized by stereotypical physiological and structural features that subserve generic computational operations. These basic computations of the cortical microcircuit emerge through the interplay of neuronal connectivity, cellular intrinsic properties, and synaptic plasticity dynamics. How these interacting mechanisms generate specific computational operations in the cortical circuit remains largely unknown. Here, we identify the neurophysiological basis of both the rate of change and anticipation computations on synaptic inputs in a cortical circuit. Through biophysically realistic computer simulations and neuronal recordings, we show that the rate-of-change computation is operated robustly in cortical networks through the combination of two ubiquitous brain mechanisms: short-term synaptic depression and spike-frequency adaptation. We then show how this rate-of-change circuit can be embedded in a convergently connected network to anticipate temporally incoming synaptic inputs, in quantitative agreement with experimental findings on anticipatory responses to moving stimuli in the primary visual cortex. Given the robustness of the mechanism and the widespread nature of the physiological machinery involved, we suggest that rate-of-change computation and temporal anticipation are principal, hard-wired functions of neural information processing in the cortical microcircuit.

  6. Infant phantom head circuit board for EEG head phantom and pediatric brain simulation

    Science.gov (United States)

    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.

  7. Distributed dynamical computation in neural circuits with propagating coherent activity patterns.

    Directory of Open Access Journals (Sweden)

    Pulin Gong

    2009-12-01

    Full Text Available Activity in neural circuits is spatiotemporally organized. Its spatial organization consists of multiple, localized coherent patterns, or patchy clusters. These patterns propagate across the circuits over time. This type of collective behavior has ubiquitously been observed, both in spontaneous activity and evoked responses; its function, however, has remained unclear. We construct a spatially extended, spiking neural circuit that generates emergent spatiotemporal activity patterns, thereby capturing some of the complexities of the patterns observed empirically. We elucidate what kind of fundamental function these patterns can serve by showing how they process information. As self-sustained objects, localized coherent patterns can signal information by propagating across the neural circuit. Computational operations occur when these emergent patterns interact, or collide with each other. The ongoing behaviors of these patterns naturally embody both distributed, parallel computation and cascaded logical operations. Such distributed computations enable the system to work in an inherently flexible and efficient way. Our work leads us to propose that propagating coherent activity patterns are the underlying primitives with which neural circuits carry out distributed dynamical computation.

  8. Developing an ARM based GNU/Linux Operating System for Single Board Computer – Cubietruck

    Directory of Open Access Journals (Sweden)

    S.Pravin Kumar

    2014-12-01

    Full Text Available The design and implementation of a Monolithic-Kernel Single Board Computer (SBC - Cubietruck GNU/Linux-like operating system on ARM platform in technical details, including boot loader design - UBOOT, building the Kernel - uImage, design of root file system and init process. The Single Board Computer Operating System (SBC OS is developed on Linux platform with GNU tool chain. The SBC OS can be used for both SBC system application development and related curriculum teaching. Single Board Computer like embedded system related curriculums are already become necessary components for undergraduate computer majors. The system is mainly designed for the purpose of technical research and curriculum based teaching and students to learn, study and more readable, of which the source codes can be provided to students, guiding them to design tiny operating system on ARM platform from scratch.

  9. Computer science security research and human subjects: emerging considerations for research ethics boards.

    Science.gov (United States)

    Buchanan, Elizabeth; Aycock, John; Dexter, Scott; Dittrich, David; Hvizdak, Erin

    2011-06-01

    This paper explores the growing concerns with computer science research, and in particular, computer security research and its relationship with the committees that review human subjects research. It offers cases that review boards are likely to confront, and provides a context for appropriate consideration of such research, as issues of bots, clouds, and worms enter the discourse of human subjects review.

  10. Seeing chips : analog VLSI circuits for computer vision

    OpenAIRE

    Koch, Christof

    1989-01-01

    Vision is simple. We open our eyes and, instantly, the world surrounding us is perceived in all its splendor. Yet Artificial Intelligence has been trying with very limited success for over 20 years to endow machines with similar abilities. A large van, filled with computers and driving unguided at a mile per hour across gently sloping hills in Colorado and using a laser-range system to “see” is the most we have accomplished so far. On the other hand, computers can play a decent game of chess ...

  11. Efficient quantum circuits for one-way quantum computing.

    Science.gov (United States)

    Tanamoto, Tetsufumi; Liu, Yu-Xi; Hu, Xuedong; Nori, Franco

    2009-03-13

    While Ising-type interactions are ideal for implementing controlled phase flip gates in one-way quantum computing, natural interactions between solid-state qubits are most often described by either the XY or the Heisenberg models. We show an efficient way of generating cluster states directly using either the imaginary SWAP (iSWAP) gate for the XY model, or the sqrt[SWAP] gate for the Heisenberg model. Our approach thus makes one-way quantum computing more feasible for solid-state devices.

  12. Multi parametric card to personal computers interface based in ispLSI1016 circuits

    International Nuclear Information System (INIS)

    It is described the design and principal characteristic of the interface circuit for a 16 bit multi parametric add on card for IBM or compatible microcomputer which content two communication channels of direct memory access and bidirectional between the card and the computer, an interrupt controller, a programmable address register, a default add res register of the card, a four channels multiplexer, as well as the decoder logic of the 80C186 and computer. The circuit was designed with two programmable logic devices ispL1016, which allowed drastically to diminish the quantity of utilized components and get a more flexible design in less time better characteristics

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

    Science.gov (United States)

    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.

  14. Computer simulation of the thermal environment of large-scale integrated circuits - Computer time-saving techniques.

    Science.gov (United States)

    Thompson, R. R.; Blum, H. A.

    1971-01-01

    This paper is concerned with the computer costs for both the steady-state and transient thermal responses of large-scale integrated circuits (LSI) when metal is present within the substrate. For the more cost-sensitive transient case, an extrapolation technique for computer time savings is compared with the accuracy loss in this study. This approach could be useful for design-cost planning.

  15. Solid state multi-ensemble quantum computer in waveguide circuit model

    CERN Document Server

    Moiseev, Sergey A; Gubaidullin, Firdus F

    2010-01-01

    The first realization of solid state quantum computer was demonstrated recently by using artificial atoms -- transmons in superconducting resonator. Here, we propose a novel architecture of flexible and scalable quantum computer based on a waveguide circuit coupling many quantum nodes of controlled atomic ensembles. For the first time, we found the optimal practically attainable parameters of the atoms and circuit for 100{%} efficiency of quantum memory for multi qubit photon fields and confirmed experimentally the predicted perfect storage. Then we revealed self modes for reversible transfer of qubits between the quantum memory node and arbitrary other nodes. We found a realization of iSWAP gate via direct coupling of two arbitrary nodes with a processing rate accelerated proportionally to number of atoms in the node. A large number of the two-qubit gates can be simultaneously realized in the circuit for implementation of parallel quantum processing. Dynamic coherent elimination procedure of excess quantum s...

  16. Bi-directional homogenization equivalent modeling for the prediction of thermo-mechanical properties of a multi-layered printed circuit board (PCB)

    International Nuclear Information System (INIS)

    Warpage of multi-layered printed circuit boards (PCB) during the reflow process is a serious problem which affects the reliability of solder ball connections between the PCB and the mounted semi-conductor packages in electronic devices. It is essential to predict the warpage of the PCB accurately; however, the complicated copper patterns in multi-layered PCBs render a full modeling analysis impossible due to the excessive computing time required. To overcome this problem, we have developed analytical equations of three Cu patterns (line, square, and grid) for the application of thermo-mechanical properties simply by equivalent modeling of Cu patterns. In the proposed equations, the effect of thermo-viscoelastic properties as well as the influence of surrounding layers such as woven glass fabric/BT (bismaleimide triazine), composite laminate (BT core), and photoimageable solder resist (PSR) were considered. To verify the developed equations, vibration tests based on the wave propagation approach were performed at various temperatures. Good agreement was observed between the equivalent model and the experimental results. (paper)

  17. Packaging strategies for printed circuit board components. Volume I, materials & thermal stresses.

    Energy Technology Data Exchange (ETDEWEB)

    Neilsen, Michael K. (Kansas City Plant, Kansas City, MO); Austin, Kevin N.; Adolf, Douglas Brian; Spangler, Scott W.; Neidigk, Matthew Aaron; Chambers, Robert S.

    2011-09-01

    Decisions on material selections for electronics packaging can be quite complicated by the need to balance the criteria to withstand severe impacts yet survive deep thermal cycles intact. Many times, material choices are based on historical precedence perhaps ignorant of whether those initial choices were carefully investigated or whether the requirements on the new component match those of previous units. The goal of this program focuses on developing both increased intuition for generic packaging guidelines and computational methodologies for optimizing packaging in specific components. Initial efforts centered on characterization of classes of materials common to packaging strategies and computational analyses of stresses generated during thermal cycling to identify strengths and weaknesses of various material choices. Future studies will analyze the same example problems incorporating the effects of curing stresses as needed and analyzing dynamic loadings to compare trends with the quasi-static conclusions.

  18. Encountering the Expertise Reversal Effect with a Computer-Based Environment on Electrical Circuit Analysis

    Science.gov (United States)

    Reisslein, Jana; Atkinson, Robert K.; Seeling, Patrick; Reisslein, Martin

    2006-01-01

    This study examined the effectiveness of a computer-based environment employing three example-based instructional procedures (example-problem, problem-example, and fading) to teach series and parallel electrical circuit analysis to learners classified by two levels of prior knowledge (low and high). Although no differences between the…

  19. 智能型电动机软起动器控制电路板测试系统设计%Design of Measurement System for Control Circuit Board of Intelligent Motor Soft Starter

    Institute of Scientific and Technical Information of China (English)

    李鑫; 戴梅; 顾启民; 谢启; 季绍陵

    2011-01-01

    The measurement of intelligent motor soft starter control circuit board performance parameter is an important means to develop a new product and guarantee product quality. Based on requirement analysis, an automatic measurement system of performance parameter for intelligent motor soft starter control circuit board based on virtual instrument technology was designed and implemented. This system was composed of industrial computer, data acquisition card and signal conditioning circuit, etc. Using LabVIEW virtual instrument technology plat-form, the related test and data processing program codes were developed, and its high speed data acquisition and data processing satisfied the needs of ex-factory performance parameter measurement for intelligent motor soft starter control circuit board. The hardware design was given and the working principles of this system were introduced; and the module design of system software was also introduced in detail. Practical application shows that the intelligent measurement system features high precision, strong disturbance attenuation, high efficiency, and easy operation and maintenance. Besides, it can improve the design and performance of products, which can be widely used. The system provides an effective way to design the performance parameter measurement system for intelligent motor soft starter control circuit board.%在需求分析基础上设计并实现了一种利用虚拟仪器技术构建的智能型电动机软起动器控制电路板性能参数自动测试系统.系统以工业控制计算机为核心,配置高精度数据采集卡和信号调理电路等硬件,采用先进的虚拟仪器技术——LabvIEw软件开发平台自行开发数据采集、分析、处理软件,实现了对智能型电动机软起动器控制电路板的自动测试.详细分析了系统总体方案设计,阐述了系统软件模块设计.经实际应用表明,该系统具有测试精度高、抗干扰能力强、检测效

  20. Design of Test System for Control Circuit Board of Residual Current Fire Monitoring Detector%剩余电流式电气火灾监控探测器控制电路板检测系统设计

    Institute of Scientific and Technical Information of China (English)

    陈景波; 谢启; 顾启民; 涂水林; 季绍陵

    2012-01-01

    Performance parameters test for control circuit board of residual current fire monitoring detector is an important means to develop new product and guarantee product quality. Based on requirement analysis , an automatic test system of performance parameter for residual current fire monitoring detector control circuit board based on virtual instrument technology was designed and implemented. The hardware was composed of industrial computer, data acquisition card and signal conditioning circuit, etc. Using LabVIEW virtual instrument technology platform, the related test and data processing program codes were developed, the system satisfied the needs of performance parameter test for residual current fire monitoring detector control circuit board. Practical application shows that the intelligent test system features with high precision, high efficiency, and can provide an effective way to design the performance parameter measurement system for residual current fire monitoring detector control circuit board.%剩余电流式电气火灾监控探测器控制电路板的性能参数检测是进行新产品研发和保证产品生产质量的重要手段;在需求分析基础上设计并实现了一种利用虚拟仪器技术构建的剩余电流式电气火灾监控探测器控制电路板性能参数自动检测系统;硬件由工业控制计算机、高精度数据采集卡和信号调理电路等构建,软件采用LabVIEW平台开发,完成数据采集、分析、处理和显示的功能,整体实现了对剩余电流式电气火灾监控探测器控制电路板的自动测试;实际应用证明,该系统具有高的测试精度和效率,为简单快速检测剩余电流式电气火灾监控探测器控制电路板提供了一种有效的方法.

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

    Science.gov (United States)

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

    2016-10-01

    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.

  2. Investigation of measuring hazardous substances in printed circuit boards using the micro-focus X-ray fluorescence screening

    CERN Document Server

    Fu, M L; Fakhrtdinov, R; Grigoriev, M; Quan, B S; Le, Z C; Roshchupkin, D

    2014-01-01

    Printed circuit boards (PCBs) are widely used in most electrical and electronic equipments or products. Hazardous substances such as Pb, Hg, Cd, etc, can be present in high concentrations in PCBs and the degradation and release of these substances poses a huge threat to humans and the environment. To investigation the chemical composition of PCBs in domestic market of China, a practical micro-focus X-ray fluorescence system is setup to make the elements analysis, especially for detecting hazardous substances. Collimator is adopted to focus the X-ray emitted from X-ray tube. BRUKER X-ray detector with proportional counter is used to detect the emitted fluorescence from the PCB samples. Both single layer PCB samples and double layers PCB samples made of epoxy glass fiber are purchased from the domestic market of China. Besides, a MC55 wireless communication module made by SIEMENS in Germany is used as the reference material. Experimental results from the fluorescence spectrums of the testing points of PCB sampl...

  3. Electrostatic separation for multi-size granule of crushed printed circuit board waste using two-roll separator

    International Nuclear Information System (INIS)

    The electrostatic separation is an effective method for recycle of crushed waste electrical and electronic equipment (WEEE). However, the robustness of the classical roll-type separator is vulnerable because of its sensitivity to variation of granule size. A new 'two-roll type corona-electrostatic separator' was built to overcome the limitation of the classical one considering the actual situation of the industrial application which always contains granule with different size. Multi-size granule of crushed printed circuit board (PCB) wastes was used for investigation and the results showed that the efficiency of the separation process was improved by using the new separator. Compared with the process (lower voltage) performed on the old separator, the metal products increased 34% while the middling products reduced 73%, respectively. Compared with the process (higher voltage) performed on the old separator, the metal products increased 22% while the middling products reduced 59%, respectively. In addition, the metal component of the middling products using new machine notably decreased, 33% (new machine) compared with 58% (lower voltage) and 66% (higher voltage). The efficiency of the separation process is enhanced compared with the classical one

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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. PMID:18554788

  6. Production and characterization of polypropylene composites filled with glass fibre recycled from pyrolysed waste printed circuit boards.

    Science.gov (United States)

    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. PMID:25176309

  7. Direct extraction of palladium and silver from waste printed circuit boards powder by supercritical fluids oxidation-extraction process.

    Science.gov (United States)

    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. PMID:27427888

  8. Electrostatic separation for multi-size granule of crushed printed circuit board waste using two-roll separator.

    Science.gov (United States)

    Wu, Jiang; Li, Jia; Xu, Zhenming

    2008-11-30

    The electrostatic separation is an effective method for recycle of crushed waste electrical and electronic equipment (WEEE). However, the robustness of the classical roll-type separator is vulnerable because of its sensitivity to variation of granule size. A new "two-roll type corona-electrostatic separator" was built to overcome the limitation of the classical one considering the actual situation of the industrial application which always contains granule with different size. Multi-size granule of crushed printed circuit board (PCB) wastes was used for investigation and the results showed that the efficiency of the separation process was improved by using the new separator. Compared with the process (lower voltage) performed on the old separator, the metal products increased 34% while the middling products reduced 73%, respectively. Compared with the process (higher voltage) performed on the old separator, the metal products increased 22% while the middling products reduced 59%, respectively. In addition, the metal component of the middling products using new machine notably decreased, 33% (new machine) compared with 58% (lower voltage) and 66% (higher voltage). The efficiency of the separation process is enhanced compared with the classical one.

  9. Recovery of copper and lead from waste printed circuit boards by supercritical water oxidation combined with electrokinetic process.

    Science.gov (United States)

    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.

  10. Application of vacuum metallurgy to separate pure metal from mixed metallic particles of crushed waste printed circuit board scraps.

    Science.gov (United States)

    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 %.

  11. Investigation of the influence of inert and oxidizing atmospheres on the efficiency of decomposition of waste printed circuit boards (WPCBs)

    Science.gov (United States)

    Kumari, Anjan; Jha, Manis Kumar; Singh, Rajendra Prasad; Ranganathan, S.

    2016-08-01

    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.

  12. Performance of the heavy fraction of pyrolysis oil derived from waste printed circuit boards in modifying asphalt.

    Science.gov (United States)

    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. PMID:23644664

  13. Occurrences and inventories of heavy metals and brominated flame retardants in wastes from printed circuit board production.

    Science.gov (United States)

    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 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. PMID:24777328

  14. Optimization of low-temperature alkaline smelting process of crushed metal enrichment originated from waste printed circuit boards

    Institute of Scientific and Technical Information of China (English)

    GUO Xue-yi; LIU Jing-xin

    2015-01-01

    A novel low-temperature alkaline smelting process is proposed to convert and separate amphoteric metals in crushed metal enrichment originated from waste printed circuit boards. The central composite design was used to optimize the operating parameters, in which mass ratio of NaOH-to-CME, smelting temperature and smelting time were chosen as the variables, and the conversions of amphoteric metals tin, lead, aluminum and zinc were response parameters. Second-order polynomial models of high significance and 3D response surface plots were constructed to show the relationship between the responses and the variables. Optimum area of 80%-85% Pb conversion and over 95% Sn conversion was obtained by the overlaid contours at mass ratio of NaOH-to-CME of 4.5-5.0, smelting temperature of 653-723 K, smelting time of 90-120 min. The models were validated experimentally in the optimum area, and the results demonstrate that these models are reliable and accurate in predicting the smelting process.

  15. Recovery of copper and lead from waste printed circuit boards by supercritical water oxidation combined with electrokinetic process

    International Nuclear Information System (INIS)

    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, Cu2O and β-PbO2 in the process. The optimum SCWO treatment conditions were 60 min, 713 K, 30 MPa, and EK treatment time, constant current density were 11 h, 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.

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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. (paper)

  18. A novel reutilization method for waste printed circuit boards as flame retardant and smoke suppressant for poly (vinyl chloride).

    Science.gov (United States)

    Xiu, Fu-Rong; Weng, Huiwei; Qi, Yingying; Yu, Gending; Zhang, Zhigang; Zhang, Fu-Shen

    2016-09-01

    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. PMID:27179704

  19. Eco-friendly copper recovery process from waste printed circuit boards using Fe3+/Fe2+ redox system

    International Nuclear Information System (INIS)

    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 Fe3+ 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%

  20. Inhibition of polybrominated dibenzo-p-dioxin and dibenzofuran formation from the pyrolysis of printed circuit boards.

    Science.gov (United States)

    Lai, Yi-Chieh; Lee, Wen-Jhy; Li, Hsing-Wang; Wang, Lin-Chi; Chang-Chien, Guo-Ping

    2007-02-01

    Waste printed circuit boards containing brominated flame retardants were pyrolyzed in a high-temperature melting system to observe the formation behaviors of polybrominated dibenzo-p-dioxins (PBDDs) and dibenzofurans (PBDFs). In this study, the results showed that the formation of PBDD/ Fs during pyrolysis can be destroyed under controlled primary combustion conditions. There were two significant factors that influenced the extent of PBDD/F formation. The first factor was temperature. The results showed that, both the total PBDD/F content in the bottom ash and the total PBDD/F emission factor from the flue gas decrease by approximately 50% with an increase of the pyrolysis temperature from 850 to 1200 degrees C. The second factor was the addition of CaO. The possible mechanism involves the reaction between CaO and HBr to form the solid-phase product CaBr2. Thus, the addition of CaO is effective in adsorbing HBr and results in the inhibition of PBDD/F synthesis by more than 90% and further prevents the acid gases (HCl and HBr) that corrode the equipment. In conclusion, due to the persistence and toxicity of PBDD/Fs, a combined regulation for controlling both PCDD/Fs and PBDD/Fs is of great importance for environmental protection issues. PMID:17328209

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

    Science.gov (United States)

    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.

  2. Nano-scale Bias-scalable CMOS Analog Computational Circuits Using Margin Propagation

    Institute of Scientific and Technical Information of China (English)

    GU Ming

    2012-01-01

    Approximation techniques are useful for implementing pattern recognizers,communication decoders and sensory processing algorithms where computational precision is not critical to achieve the desired system level performance.In our previous work,we had proposed margin propagation (MP) as an efficient piece-wise linear (PWL) approximation technique to a Iog-sumexp function and had demonstrated its advantages for implementing probabilistic decoders.In this paper,we present a systematic and a generalized approach for synthesizing analog piecewiselinear (PWL) computing circuits using the MP principle.MP circuits use only addition,subtraction and threshold operations and hence can be implemented using universal conservation principles like the Kirchoff' s current law.Thus,unlike the conventional translinear CMOS currentmode circuits,the operation of the MP circuits are functionally similar in weak,moderate and strong inversion regimes of the MOS transistor making the design approach bias-scalable.This paper presents measured results from MP circuits prototyped in a 0.5 μm standard CMOS process verifying the bias-scalable property.As an example,we apply the synthesis approach towards designing linear classifiers and verify its performance using measured results.

  3. Processamento de placas de circuito impresso de equipamentos eletroeletrônicos de pequeno porte Processing of printed circuit boards of small electrical and electronic devices

    Directory of Open Access Journals (Sweden)

    Sérgio de Souza Henrique Júnior

    2013-01-01

    Full Text Available A hydrometallurgical process applicable to printed circuit boards of small electrical and electronic devices was developed. This involved three leaching steps (60 ºC, 2 h: 6 mol L-1 NaOH, 6 mol L-1 HCl and aqua regia. NaOH removed the resin and flame retardant that covered the circuit boards. HCl dissolved the most electropositive metals and a small amount of copper (~0.3 wt%. Aqua regia dissolved the noble metals. Silver precipitated as AgCl. Gold and platinum were quantitatively extracted with pure methyl-isobutylketone and Alamine 336 (10 % vol. in kerosene, respectively. Slow evaporation of the raffinate crystallized CuCl2.4H2O (89% yield.

  4. 混装电路板焊接工艺设计%Process Design of Soldering for Mix-assembled Circuit Board

    Institute of Scientific and Technical Information of China (English)

    徐冬霞; 韩飞

    2011-01-01

    Manual iron soldering of certain mix-assembled circuit board product was used as an example, process design of soldering for mix-assembled circuit board was introduced, including criteria of soldering procedure, choice of soldering method and key points of process design. It could serve as a basis and reference for process design of like products in future.%本文以某产品的混装电路板手工焊接为例,介绍了混装电路板焊接工艺设计的过程,包括工艺设计的依据、焊接方法的选择以及工艺设计的要点,可作为今后类似产品的设计依据和参考.

  5. Computer-Assisted Troubleshooting for Efficient Off-board Diagnosis

    OpenAIRE

    Warnquist, Håkan

    2011-01-01

    This licentiate thesis considers computer-assisted troubleshooting of complex products such as heavy trucks. The troubleshooting task is to find and repair all faulty components in a malfunctioning system. This is done by performing actions to gather more information regarding which faults there can be or to repair components that are suspected to be faulty. The expected cost of the performed actions should be as low as possible. The work described in this thesis contributes to solving the tr...

  6. Hydroxylated PBDEs and brominated phenolic compounds in particulate matters emitted during recycling of waste printed circuit boards in a typical e-waste workshop of South China

    International Nuclear Information System (INIS)

    The hydroxylated PBDEs (OH-PBDEs) and brominated phenolic compounds in aerosol samples from a printed circuit boards recycling workshop were characterized. The results show that OH-PBDEs, which are naturally occurring compounds or metabolism of PBDEs, could also be emitted from the e-waste recycling. Five OH-PBDEs, several unidentified mono-OH-PBDE and di-OH-PBDE congeners were detected. The concentration of ∑OH-PBDEs was 1.74–4.22 ng m−3 (average of 2.66 ng m−3), with 6-OH-BDE-47 (0.329 ng m−3) as the most abundant identified congener. The total concentration of di- to tri-brominated phenols (BPs) was 18.8–32.0 ng m−3 (average of 26.3 ng m−3) with 2,4,6-triBP as the most abundant congener. These findings suggest that the recycling of printed circuit boards represent a strong source of OH-PBDEs and BPs to the atmosphere. Additionally, some phenolic compounds including brominated bisphenol A, hydroxylated polybrominated biphenyl species and etc. were also identified. -- Highlights: ► OH-PBDEs and BPs were abundant in the PM from printed circuit boards recycling. ► The patterns of OH-PBDEs and BPs were different from that in biotic environment. ► 6-OH-BDE-47 was the most abundant identified OH-PBDE congener. ► 2,4,6-triBP was the most abundant BP congener. ► Possible formation mechanisms of OH-PBDEs and BPs were discussed. -- Recycling of waste printed circuit boards might represent a strong source of OH-PBDEs, BPs and other phenolic compounds

  7. Distributed quantum computation with superconducting qubit via LC circuit using dressed states

    Institute of Scientific and Technical Information of China (English)

    Wu Chao; Fang Mao-Fa; Xiao Xing; Li Yan-Ling; Cao Shuai

    2011-01-01

    A scheme is proposed where two superconducting qubits driven by a classical field interacting separately with two distant LC circuits connected by another LC circuit through mutual inductance, are used for implementing quantum gates. By using dressed states, quantum state transfer and quantum entangling gate can be implemented. With the help of the time-dependent electromagnetic field, any two dressed qubits can be selectively coupled to the data bus (the last LC circuit), then quantum state can be transferred from one dressed qubit to another and multi-mode entangled state can also be formed. As a result, the promising perspectives for quantum information processing of mesoscopic superconducting qubits are obtained and the distributed and scalable quantum computation can be implemented in this scheme.

  8. 自动舵电路板故障测试系统研究%Research on fault test for circuit boards of auto rudders

    Institute of Scientific and Technical Information of China (English)

    李天伟; 李正友; 黄谦

    2013-01-01

    The fault test for the circuit board of auto rudders is usually made by the manufacturer factory. That costs too much. A new fault test system was developed to solve the problem. The authors use few data acquisition system hardware for all circuit boards, but special interface cables and special test software were designed for each kinds of board. Then many different boards can be tested by the same system. Auto test software based on neural network was developed to diagnosis normal faults. The Measurement Studio and Visual Studio were chosen to develop the test software to enrich the software interface. The system was characterized by low cost, small cubage and powerful function. The fault circuit boards can be tested on shipboard directly.%针对自动舵故障电路板需要返厂测试的问题,设计自动舵电路板便携式故障测试系统.在分析自动舵电路板故障测试需求的基础上,采用专用接口电缆和测试软件而复用数据采集系统的方法,仅用少数硬件就实现了多块电路板的测试;基于神经网络方法设计自动测试软件,能够定位电路板常见故障;采用Measurement Studio和Visual Studio联合编程的方法,设计了辅助信息丰富的故障诊断程序界面.实践表明:该系统具有成本低、体积小、功能强的特点,可在船上直接对电路板进行故障测试.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Michael L.M., E-mail: mitchel.marques@yahoo.com.br [Bio& Hydrometallurgy Laboratory, Department of Metallurgical and Materials Engineering, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35400-000 (Brazil); Leão, Versiane A., E-mail: versiane@demet.em.ufop.br [Bio& Hydrometallurgy Laboratory, Department of Metallurgical and Materials Engineering, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35400-000 (Brazil); Gomes, Otavio [Centre for Mineral Technology – CETEM, Av Pedro Calmon, 900, 21941-908 Rio de Janeiro (Brazil); Lambert, Fanny; Bastin, David; Gaydardzhiev, Stoyan [Mineral Processing and Recycling, University of Liege, SartTilman, 4000 Liege (Belgium)

    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.

  10. Leaching behavior of copper from waste printed circuit boards with Brønsted acidic ionic liquid

    International Nuclear Information System (INIS)

    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 Ea was 25.36 kJ/mol. - Abstract: 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 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]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

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

    International Nuclear Information System (INIS)

    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

  12. An assessment of alternatives for replacing Freon 113 in bench type electrical circuit board cleaning at Fermi National Accelerator Laboratory

    International Nuclear Information System (INIS)

    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

  13. Design of a Control Circuit Board for Baby Incubator%婴儿培养箱控制面板的设计

    Institute of Scientific and Technical Information of China (English)

    王秀芳

    2011-01-01

    目的 设计一种智能型、性能可靠便于医护人员操作的婴儿培养箱.方法 本文在简要介绍婴儿培养箱的组成、分析各组成部分功能的基础上,设计出以单片机P89V51RD2为控制核心的婴儿培养箱控制面板.该控制面板包括温湿度采集电路、LCD显示模块、输入键盘、报警电路等多个部分.结果 实现了婴儿培养箱温湿度采集、显示,异常时报警及紧急情况下自动处理等功能,经过长时间实验,证明该控制面板能可靠稳定地运行.结论 该婴儿培养箱控制面板稳定可靠,人机接口界面简洁明了,易于操作和维护.%Objective Objected To design an intelligent, safe, user-friendly baby incubator. Methods A control circuit board for baby incubator was designed based on the MCU P89V51RD2 after the introduction of the composition of baby incubator and the function analysis. This control circuit board includes the sample circuit, LCD display circuit, keyboard and other modules on the board. Results This baby incubator can realize the sample, display, alarm and auto-dispose of emergency about the temperature and humidity in baby incubator. After repeated experiments, it is proved that the board can run stably. Conclusions This control circuit board for baby incubator is stable, man-machine interface is concise and easy to be operated and maintained.

  14. The Effects of Computer-Assisted Instruction of Simple Circuits on Experimental Process Skills

    Directory of Open Access Journals (Sweden)

    Şeyma ULUKÖK

    2013-01-01

    Full Text Available The experimental and control groups were composed of 30 sophomores majoring in Classroom Teaching for this study investigating the effects of computer-assisted instruction of simple circuits on the development of experimental process skills. The instruction includes experiments and studies about simple circuits and its elements (serial, parallel, and mixed conncetions of resistors covered in Science and Technology Laboratory II course curriculum. In this study where quantitative and qualitative methods were used together, the control list developed by the researchers was used to collect data. Results showed that experimental process skills of sophomores in experimental group were more developed than that of those in control group. Thus, it can be said that computer-assisted instruction has a positive impact on the development of experimental process skills of students.

  15. Tight bounds on computing error-correcting codes by bounded-depth circuits with arbitrary gates

    DEFF Research Database (Denmark)

    Gal, A.; Hansen, Kristoffer Arnsfelt; Koucky, Michal;

    2013-01-01

    We bound the minimum number w of wires needed to compute any (asymptotically good) error-correcting code C:{0,1}Ω(n)→{0,1}n with minimum distance Ω(n), using unbounded fan-in circuits of depth d with arbitrary gates. Our main results are: 1) if d=2, then w=Θ(n (lgn/lglgn)2); 2) if d=3, then w=Θ(n...

  16. Tight bounds on computing error-correcting codes by bounded-depth circuits with arbitrary gates

    DEFF Research Database (Denmark)

    Gál, Anna; Hansen, Kristoffer Arnsfelt; Koucký, Michal;

    2012-01-01

    We bound the minimum number w of wires needed to compute any (asymptotically good) error-correcting code C:{0,1}Ω(n) -> {0,1}n with minimum distance Ω(n), using unbounded fan-in circuits of depth d with arbitrary gates. Our main results are: (1) If d=2 then w = Θ(n ({log n/ log log n})2). (2) If ...

  17. Computational implementation of a tunable multicellular memory circuit for engineered eukaryotic consortia

    Directory of Open Access Journals (Sweden)

    Josep eSardanyés

    2015-10-01

    Full Text Available Cells are complex machines capable of processing information by means of an entangled network ofmolecular interactions. A crucial component of these decision-making systems is the presence of memoryand this is also a specially relevant target of engineered synthetic systems. A classic example of memorydevices is a 1-bit memory element known as the flip-flop. Such system can be in principle designed usinga single-cell implementation, but a direct mapping between standard circuit design and a living circuitcan be cumbersome. Here we present a novel computational implementation of a 1-bit memory deviceusing a reliable multicellular design able to behave as a set-reset flip-flop that could be implemented inyeast cells. The dynamics of the proposed synthetic circuit is investigated with a mathematical modelusing biologically-meaningful parameters. The circuit is shown to behave as a flip-flop in a wide range ofparameter values. The repression strength for the NOT logics is shown to be crucial to obtain a goodflip-flop signal. Our model also shows that the circuit can be externally tuned to achieve different memorystates and dynamics, such as persistent and transient memory. We have characterised the parameterdomains for robust memory storage and retrieval as well as the corresponding time response dynamics.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  1. Future Directions in Computer Graphics and Visualization: From CG&A's Editorial Board

    Energy Technology Data Exchange (ETDEWEB)

    Encarnacao, L. M.; Chuang, Yung-Yu; Stork, Andre; Kasik, David; Rhyne, Theresa-Marie; Avila, Lisa; Kohlhammer, Jorn; LaViola, Joseph; Tory, Melanie; Dill, John; Domik, Gitta; Owen, G. Scott; Wong, Pak C.

    2015-01-01

    With many new members joining the CG&A editorial board over the past year, and with a renewed commitment to not only document the state of the art in computer graphics research and applications but to anticipate and where possible foster future areas of scientific discourse and industrial practice, we asked editorial and advisory council members about where they see their fields of expertise going. The answers compiled here aren’t meant to be all encompassing or deterministic when it comes to the opportunities computer graphics and interactive visualization hold for the future. Instead, we aim to accomplish two things: give a more in-depth introduction of members of the editorial board to the CG&A readership and encourage cross-disciplinary discourse toward approaching, complementing, or disputing the visions laid out in this compilation.

  2. Application of a single-board computer as a low cost pulse generator

    CERN Document Server

    Fedrizzi, Marcus

    2015-01-01

    A BeagleBone Black (BBB) single-board open-source computer was implemented as a low-cost fully programmable pulse generator. The pulse generator makes use of the BBB Programmable Real-Time Unit (PRU) subsystem to achieve a deterministic temporal resolution of 5 ns, an RMS jitter of 290 ps and a timebase stability on the order of 10 ppm. A python based software framework has also been developed to simplify the usage of the pulse generator.

  3. Application of a single-board computer as a low-cost pulse generator

    International Nuclear Information System (INIS)

    A BeagleBone Black (BBB) single-board open-source computer was implemented as a low-cost fully programmable pulse generator. The pulse generator makes use of the BBB Programmable Real-Time Unit (PRU) subsystem to achieve a deterministic temporal resolution of 5 ns, an RMS jitter of 290 ps and a timebase stability on the order of 10 ppm. A Python-based software framework has also been developed to simplify the usage of the pulse generator. (paper)

  4. Scalability of a Base Level Design for an On-Board-Computer for Scientific Missions

    Science.gov (United States)

    Treudler, Carl Johann; Schroder, Jan-Carsten; Greif, Fabian; Stohlmann, Kai; Aydos, Gokce; Fey, Gorschwin

    2014-08-01

    Facing a wide range of mission requirements and the integration of diverse payloads requires extreme flexibility in the on-board-computing infrastructure for scientific missions. We show that scalability is principally difficult. We address this issue by proposing a base level design and show how the adoption to different needs is achieved. Inter-dependencies between scaling different aspects and their impact on different levels in the design are discussed.

  5. Towards electromechanical computation: An alternative approach to realize complex logic circuits

    Science.gov (United States)

    Hafiz, M. A. A.; Kosuru, L.; Younis, M. I.

    2016-08-01

    Electromechanical computing based on micro/nano resonators has recently attracted significant attention. However, full implementation of this technology has been hindered by the difficulty in realizing complex logic circuits. We report here an alternative approach to realize complex logic circuits based on multiple MEMS resonators. As case studies, we report the construction of a single-bit binary comparator, a single-bit 4-to-2 encoder, and parallel XOR/XNOR and AND/NOT logic gates. Toward this, several microresonators are electrically connected and their resonance frequencies are tuned through an electrothermal modulation scheme. The microresonators operating in the linear regime do not require large excitation forces, and work at room temperature and at modest air pressure. This study demonstrates that by reconfiguring the same basic building block, tunable resonator, several essential complex logic functions can be achieved.

  6. Towards electromechanical computation: An alternative approach to realize complex logic circuits

    KAUST Repository

    Hafiz, M. A. A.

    2016-08-18

    Electromechanical computing based on micro/nano resonators has recently attracted significant attention. However, full implementation of this technology has been hindered by the difficulty in realizing complex logic circuits. We report here an alternative approach to realize complex logic circuits based on multiple MEMS resonators. As case studies, we report the construction of a single-bit binary comparator, a single-bit 4-to-2 encoder, and parallel XOR/XNOR and AND/NOT logic gates. Toward this, several microresonators are electrically connected and their resonance frequencies are tuned through an electrothermal modulation scheme. The microresonators operating in the linear regime do not require large excitation forces, and work at room temperature and at modest air pressure. This study demonstrates that by reconfiguring the same basic building block, tunable resonator, several essential complex logic functions can be achieved.

  7. Design and analysis of the reliability of on-board computer system based on Markov-model

    Institute of Scientific and Technical Information of China (English)

    MA Xiu-juan; CAO Xi-bin; ZHAO Guo-liang

    2005-01-01

    An on-board computer system should have such advantages as light weight, small volume and low power to meet the demand of micro-satellites. This paper, based on specific characteristics of Stereo Mapping Micro-Satellite ( SMMS), describes the on-board computer system with its advantage of having centralized and distributed control in the same system and analyzes its reliability based on a Markov model in order to provide a theoretical foundation for a reliable design. The on-board computer system has been put into use in principle prototype model of Stereo Mapping Micro-Satellite and has already been debugged. All indexes meet the requirements of the design.

  8. A COTS-based single board radiation-hardened computer for space applications

    International Nuclear Information System (INIS)

    There is great community interest in the ability to use COTS (Commercial-Off-The-Shelf) technology in radiation environments. Space Electronics, Inc. has developed a high performance COTS-based radiation hardened computer. COTS approaches were selected for both hardware and software. Through parts testing, selection and packaging, all requirements have been met without parts or process development. Reliability, total ionizing dose and single event performance are attractive. The characteristics, performance and radiation resistance of the single board computer will be presented. (authors)

  9. 废弃电路板回收技术与方法研究进展%Research Development of Printed Circuit Board Recycling Technologies and Methods

    Institute of Scientific and Technical Information of China (English)

    唐德文; 邹树梁; 刘衣昌; 刘益强

    2014-01-01

    With view to the current situation of waste printed circuit board( PCB) disposi-tion in China,waste printed circuit boards will cause serious environmental pollution,and the use of waste printed circuit boards can be an enormous economic value. This paper in-troduced the great need and importance of PCB recovery and recycling,the main technolo-gies and equipments including mechanical separation,chemical,biological hydrometallurgi-cal technology,supercritical fluid technology. And for sustainable development,the author came up with a prospect on the further studies in this field.%随着电子制造业飞速发展,废弃电路板急剧增加,如何有效处理废弃电路板并提高它的利用率已成为大家所关注的热点问题。废弃电子线路板如果处理不当将会对环境造成严重的污染,综合利用好废弃电路板又可产生巨大的经济价值。本文阐述我国进行废弃电子线路板回收和处理的重要性和紧迫性,在此基础上,分别对废弃电路板机械处理法、化学法、生物湿法冶金技术、超临界流体技术等回收与处理技术与方法的研究现状进行了综述,并对其研究重点和发展趋势做出展望。

  10. 1st International Conference on Computational Advancement in Communication Circuits and Systems

    CERN Document Server

    Dalapati, Goutam; Banerjee, P; Mallick, Amiya; Mukherjee, Moumita

    2015-01-01

    This book comprises the proceedings of 1st International Conference on Computational Advancement in Communication Circuits and Systems (ICCACCS 2014) organized by Narula Institute of Technology under the patronage of JIS group, affiliated to West Bengal University of Technology. The conference was supported by Technical Education Quality Improvement Program (TEQIP), New Delhi, India and had technical collaboration with IEEE Kolkata Section, along with publication partner by Springer. The book contains 62 refereed papers that aim to highlight new theoretical and experimental findings in the field of Electronics and communication engineering including interdisciplinary fields like Advanced Computing, Pattern Recognition and Analysis, Signal and Image Processing. The proceedings cover the principles, techniques and applications in microwave & devices, communication & networking, signal & image processing, and computations & mathematics & control. The proceedings reflect the conference’s emp...

  11. Development of a computer code for dynamic analysis of the primary circuit of advanced reactors

    International Nuclear Information System (INIS)

    Currently, advanced reactors are being developed, seeking for enhanced safety, better performance and low environmental impacts. Reactor designs must follow several steps and numerous tests before a conceptual project could be certified. In this sense, computational tools become indispensable in the preparation of such projects. Thus, this study aimed at the development of a computational tool for thermal-hydraulic analysis by coupling two computer codes to evaluate the influence of transients caused by pressure variations and flow surges in the region of the primary circuit of IRIS reactor between the core and the pressurizer. For the simulation, it was used a situation of 'insurge', characterized by the entry of water in the pressurizer, due to the expansion of the refrigerant in the primary circuit. This expansion was represented by a pressure disturbance in step form, through the block 'step' of SIMULINK, thus enabling the transient startup. The results showed that the dynamic tool, obtained through the coupling of the codes, generated very satisfactory responses within model limitations, preserving the most important phenomena in the process. (author)

  12. Development of a computer code for dynamic analysis of the primary circuit of advanced reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Jussie Soares da; Lira, Carlos A.B.O.; Magalhaes, Mardson A. de Sa, E-mail: cabol@ufpe.b [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2011-07-01

    Currently, advanced reactors are being developed, seeking for enhanced safety, better performance and low environmental impacts. Reactor designs must follow several steps and numerous tests before a conceptual project could be certified. In this sense, computational tools become indispensable in the preparation of such projects. Thus, this study aimed at the development of a computational tool for thermal-hydraulic analysis by coupling two computer codes to evaluate the influence of transients caused by pressure variations and flow surges in the region of the primary circuit of IRIS reactor between the core and the pressurizer. For the simulation, it was used a situation of 'insurge', characterized by the entry of water in the pressurizer, due to the expansion of the refrigerant in the primary circuit. This expansion was represented by a pressure disturbance in step form, through the block 'step' of SIMULINK, thus enabling the transient startup. The results showed that the dynamic tool, obtained through the coupling of the codes, generated very satisfactory responses within model limitations, preserving the most important phenomena in the process. (author)

  13. Effect of Multiphoton Processes on Geometric Quantum Computation in Superconducting Circuit QED

    Institute of Scientific and Technical Information of China (English)

    CHEN Chang-Yong

    2012-01-01

    We study the influence of multi-photon processes on the geometric quantum computation in the systems of superconducting qubits based on the displacement-like and the general squeezed operator methods. As an example, we focus on the question about how to implement a two-qubit geometric phase gate using superconducting circuit quantum electrodynamics with both single- and two-photon interaction between the qubits and the cavity modes. We find that the multiphoton processes are not only controllable but also improve the gating speed. The comparison with other physical systems and experimental feasibility are discussed in detail.

  14. DIADEME: A computer code to assess in operation defective fuel characteristics and primary circuit contamination

    International Nuclear Information System (INIS)

    DIADEME is a computer code developed within the framework of R and D cooperation between the French Atomic Energy Commission (CEA), Electricite de France (EdF) and FRAMATOME-ANP. Its aim is to assess in operation defective fuel characteristics and primary circuit contamination for actinides and long half-life fission products involved in health physics problems as well as in waste and decommissioning studies. DIADEME has been developed and qualified for the EDF nuclear power plants. For many years, both theoretical and experimental studies have been carried out at the CEA on the release of fission products and actinides out of defective fuel rods in operation, their migration and deposition in PWR primary circuits. These studies have allowed defect characteristic diagnosis methods to be developed, based on radiochemical measurements of the primary coolant. These methods are generally used along with gamma spectrometry measurements on primary water sampling. In order to be completely efficient, these methods can also be used in connection with an on-line primary water gamma spectrometry device. This permits to obtain the most comprehensive data on fission product activity evolutions at steady state and during operation transients, and allows the on-line characterization of the defective fuel assemblies. For long half-life fission products and for actinides, DIADEME is also able to assess the activities of soluble and insoluble forms in the primary water and in the chemical and voluminal control system (CVCS) filters and resins, as well as those activities deposited on primary circuit surfaces. (author)

  15. A real-time fault-tolerant scheduling algorithm with low dependability cost in on-board computer system

    Institute of Scientific and Technical Information of China (English)

    WANG Pei-dong; WEI Zhen-hua

    2008-01-01

    To make the on-board computer system more dependable and real-time in a satellite, an algorithm of the fault-tolerant scheduling in the on-board computer system with high priority recovery is proposed in this paper. This algorithm can schedule the on-board fault-tolerant tasks in real time. Due to the use of dependability cost, the overhead of scheduling the fault-tolerant tasks can be reduced. The mechanism of the high priority recovery will improve the response to recovery tasks. The fault-tolerant scheduling model is presented simulation results validate the correctness and feasibility of the proposed algorithm.

  16. 废旧线路板中塑料的回收及利用%Recycling and Reusing of Plastic in Waste Printed Circuit Board

    Institute of Scientific and Technical Information of China (English)

    李启胜

    2012-01-01

    总结了废旧线路板中塑料的回收处置方法和废旧线路板中塑料的回收利用现状.重点介绍了废旧线路板中塑料的物理回收法、热解回收法和溶液回收法,在综合比较废旧线路板中塑料回收利用的各种方法的基础上展望了废旧线路板中塑料回收利用的发展趋势.%The recycling technology and comprehensive application-situation of plastic in waste printed circuit board were summarized, and the physical recovery method, pyrolysis recovery method and solution recovery method were mainly introduced. On the basis of comprehensive comparing of the recycling methods, the recyling trends of plastic in waste printed circuit board was prospected.

  17. Design and implementation of GPS embedded receiver based on ARM integrated circuit board%内置ARM板卡GPS接收机设计与实现

    Institute of Scientific and Technical Information of China (English)

    杜娟; 马辉; 刘星; 刘丙申

    2012-01-01

    随着信息化科技的不断发展,GPS在很多领域得到了广泛的应用.本文以GPS系统为蓝图,用ARM板卡技术作为平台设计了嵌入式GPS接收机,并对接收的动态试验数据精度进行分析,证明了基于ARM板卡的嵌入式GPS接收机在GPS系统中应用的可行性.%GPS is applied widely in more fields with the developing of information science and technology. In this paper, the system of multi-objective GPS was taken for a blueprint and ARM integrated circuit board technology was taken as the platform, GPS embedded receiver was designed. And the precision of dynamic test data received was analyzed. The results showed that it was feasible that GPS embedded receiver based on ARM integrated circuit board technology was applied in the GPS system.

  18. 谈PCB企业中央研究院的战略定位%The strategic positioning of printed circuit board enterprise center institute

    Institute of Scientific and Technical Information of China (English)

    黄勇; 朱兴华; 陈正清; 吴会兰

    2012-01-01

    This article focuses on the strategic positioning of printed circuit board enterprise center institute, By constructing a entities department of printed circuit board enterprise institute to create the basis platform of the technological innovation system, from the strategic height to make its overall planning, enhance the innovation capability and core competitiveness, eventually become the center of technological and product innovation, the center of innovation management and resource integration, the Center of industrial planning and the center of talent aggregation. The four centers are interdependent with each other.%主要讲述了电路板企业中央研究院的战略定位,通过组建中央研究院实体部门,建立企业创新研究体系的基础平台,从战略高度对其进行整体规划,增强中央研究院的创新能力和核心竞争力,最终成为企业的产品技术研发中心、创新管理及资源整合中心、发展规划中心和人才聚合中心。四大中心职能相互依赖,相互配合。

  19. Efficient physical embedding of topologically complex information processing networks in brains and computer circuits.

    Directory of Open Access Journals (Sweden)

    Danielle S Bassett

    2010-04-01

    Full Text Available Nervous systems are information processing networks that evolved by natural selection, whereas very large scale integrated (VLSI computer circuits have evolved by commercially driven technology development. Here we follow historic intuition that all physical information processing systems will share key organizational properties, such as modularity, that generally confer adaptivity of function. It has long been observed that modular VLSI circuits demonstrate an isometric scaling relationship between the number of processing elements and the number of connections, known as Rent's rule, which is related to the dimensionality of the circuit's interconnect topology and its logical capacity. We show that human brain structural networks, and the nervous system of the nematode C. elegans, also obey Rent's rule, and exhibit some degree of hierarchical modularity. We further show that the estimated Rent exponent of human brain networks, derived from MRI data, can explain the allometric scaling relations between gray and white matter volumes across a wide range of mammalian species, again suggesting that these principles of nervous system design are highly conserved. For each of these fractal modular networks, the dimensionality of the interconnect topology was greater than the 2 or 3 Euclidean dimensions of the space in which it was embedded. This relatively high complexity entailed extra cost in physical wiring: although all networks were economically or cost-efficiently wired they did not strictly minimize wiring costs. Artificial and biological information processing systems both may evolve to optimize a trade-off between physical cost and topological complexity, resulting in the emergence of homologous principles of economical, fractal and modular design across many different kinds of nervous and computational networks.

  20. The functional consequences of cortical circuit abnormalities on gamma oscillations in schizophrenia: insights from computational modeling

    Directory of Open Access Journals (Sweden)

    Kevin M Spencer

    2009-10-01

    Full Text Available Schizophrenia is characterized by cortical circuit abnormalities, which might be reflected in γ-frequency (30-100 Hz oscillations in the electroencephalogram. Here we used a computational model of cortical circuitry to examine the effects that neural circuit abnormalities might have on γ generation and network excitability. The model network consisted of 1000 leaky integrate-and-fire neurons with realistic connectivity patterns and proportions of neuron types (pyramidal cells [PCs], regular-spiking inhibitory interneurons, and fast-spiking interneurons [FSIs]. The network produced a γ oscillation when driven by noise input. We simulated reductions in 1 recurrent excitatory inputs to PCs; 2 both excitatory and inhibitory inputs to PCs; 3 all possible connections between cells; 4 reduced inhibitory output from FSIs; and 5 reduced NMDA input to FSIs. Reducing all types of synaptic connectivity sharply reduced γ power and phase synchrony. Network excitability was reduced when recurrent excitatory connections were deleted, but the network showed disinhibition effects when inhibitory connections were deleted. Reducing FSI output impaired γ generation to a lesser degree than reducing synaptic connectivity, and increased network excitability. Reducing FSI NMDA input also increased network excitability, but increased γ power. The results of this study suggest that a multimodal approach, combining non-invasive neurophysiological and structural measures, might be able to distinguish between different neural circuit abnormalities in schizophrenia patients. Computational modeling may help to bridge the gaps between post-mortem studies, animal models, and experimental data in humans, and facilitate the development of new therapies for schizophrenia and neuropsychiatric disorders in general.

  1. The impact of adult neurogenesis on olfactory bulb circuits and computations.

    Science.gov (United States)

    Lepousez, Gabriel; Valley, Matthew T; Lledo, Pierre-Marie

    2013-01-01

    Modern neuroscience has demonstrated how the adult brain has the ability to profoundly remodel its neurons in response to changes in external stimuli or internal states. However, adult brain plasticity, although possible throughout life, remains restricted mostly to subcellular levels rather than affecting the entire cell. New neurons are continuously generated in only a few areas of the adult brain-the olfactory bulb and the dentate gyrus-where they integrate into already functioning circuitry. In these regions, adult neurogenesis adds another dimension of plasticity that either complements or is redundant to the classical molecular and cellular mechanisms of plasticity. This review extracts clues regarding the contribution of adult-born neurons to the different circuits of the olfactory bulb and specifically how new neurons participate in existing computations and enable new computational functions. PMID:23190074

  2. Quantum computing with photons: introduction to the circuit model, the one-way quantum computer, and the fundamental principles of photonic experiments

    Science.gov (United States)

    Barz, Stefanie

    2015-04-01

    Quantum physics has revolutionized our understanding of information processing and enables computational speed-ups that are unattainable using classical computers. This tutorial reviews the fundamental tools of photonic quantum information processing. The basics of theoretical quantum computing are presented and the quantum circuit model as well as measurement-based models of quantum computing are introduced. Furthermore, it is shown how these concepts can be implemented experimentally using photonic qubits, where information is encoded in the photons’ polarization.

  3. Checking a printed board

    CERN Multimedia

    1977-01-01

    An 'Interactive Printed Circuit Board Design System' has been developed by a company in a Member-State. Printed circuits are now produced at the SB's surface treatment workshop using a digitized photo-plotter.

  4. Evaluating the Effects of Aging on Electronic Instrument and Control Circuit Boards and Components in Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Evaluating the Effects of Aging on Electronic Instrument and Control Circuit Boards and Components in Nuclear Power Plants

    International Nuclear Information System (INIS)

    The report describes potentially useful techniques for monitoring the aging of I and 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

  6. Simple modeling for conducted common-mode current in switching circuits

    OpenAIRE

    Kchikach, M; Yuan, YS; Qian, ZM; Pong, MH

    2001-01-01

    Common mode current strongly depends on stray capacitance of each circuit node, especially those with high dv/dt and di/dt. To build a simple model for conducted common mode current in switching circuit a computer software based on Partial Element Equivalent Circuit (PEEC) method is used to calculate the parasitic elements of the printed circuit board (PCB). Simulation results agree well with experimental results up to 10 MHz.

  7. A computer-controlled, on-board data acquisition system for wind-tunnel testing

    Science.gov (United States)

    Finger, H. J.; Cambra, J. M.

    1974-01-01

    A computer-controlled data acquisition system has been developed for the 40x80-foot wind tunnel at Ames Research Center. The system, consisting of several small onboard units installed in the model and a data-managing, data-displaying ground station, is capable of sampling up to 256 channels of raw data at a total sample rate of 128,000 samples/sec. Complete signal conditioning is contained within the on-board units. The sampling sequence and channel gain selection is completely random and under total control of the ground station. Outputs include a bar-graph display, digital-to-analog converters, and digital interface to the tunnel's central computer, an SEL 840MP. The system can be run stand-alone or under the control of the SEL 840MP.

  8. Kajian dan Implementasi Real Time Operating System pada Single Board Computer Berbasis ARM

    Directory of Open Access Journals (Sweden)

    Wiedjaja

    2014-06-01

    Full Text Available Operating System is an important software in computer system. For personal and office use the operating system is sufficient. However, to critical mission applications such as nuclear power plants and braking system on the car (auto braking system which need a high level of reliability, it requires operating system which operates in real time. The study aims to assess the implementation of the Linux-based operating system on a Single Board Computer (SBC ARM-based, namely Pandaboard ES with the Dual-core ARM Cortex-A9, TI OMAP 4460 type. Research was conducted by the method of implementation of the General Purpose OS Ubuntu 12:04 OMAP4-armhf-RTOS and Linux 3.4.0-rt17 + on PandaBoard ES. Then research compared the latency value of each OS on no-load and with full-load condition. The results obtained show the maximum latency value of RTOS on full load condition is at 45 uS, much smaller than the maximum value of GPOS at full-load at 17.712 uS. The lower value of latency demontrates that the RTOS has ability to run the process in a certain period of time much better than the GPOS.

  9. Hardware Design of a General Digital Circuit Board Testing System%通用数字电路板测试系统硬件设计

    Institute of Scientific and Technical Information of China (English)

    周博; 刘文波

    2012-01-01

    The conventional method of using an oscilloscope, muhimeter, logic analyzer or other equipment for digital circuit board testing is complex, time consuming and not reliable. In this paper, the hardware design of a general digital circuit board testing system is introduced. Unlike traditional digital circuit board testing systems, this design has better performance and parameters: the testing frequency can reach 50 MHz and can be set as integer di- vision of 100 MHz; the testing level is compatible to -6 V - + 9 V and can be programmed by 100 mV ; there are up to 32 channels, each channel having 1 Mbit memory depth and 50 mA current drive capability with overload pro- tection, and can work either as input or output for three-state synchronously.%针对传统依靠人工使用示波器、万用表、逻辑分析仪等设备对数字电路板进行测试具有过程复杂、工作量大、可靠性低等缺点,介绍一套通用数字电路板测试系统的硬件设计方案。跟传统数字电路板测试系统相比,文中的设计性能参数更优,主要包括:测试频率最高50MHz并可调为100MHz的整数分频;测试电平兼容-6~+9V且可编程步长为100mV;测试通道32路,每通道可设为输入输出三态可选且同步工作,存储深度1Mbit,电流驱动能力达50mA并有过载保护。

  10. Emerging materials and devices in spintronic integrated circuits for energy-smart mobile computing and connectivity

    International Nuclear Information System (INIS)

    A spintronic integrated circuit (IC) is made of a combination of a semiconductor IC and a dense array of nanometer-scale magnetic tunnel junctions. This emerging field is of growing scientific and engineering interest, owing to its potential to bring disruptive device innovation to the world of electronics. This technology is currently being pursued not only for scalable non-volatile spin-transfer-torque magnetoresistive random access memory, but also for various forms of non-volatile logic (Spin-Logic). This paper reviews recent advances in spintronic IC. Key discoveries and breakthroughs in materials and devices are highlighted in light of the broader perspective of their application in low-energy mobile computing and connectivity systems, which have emerged as leading drivers for the prevailing electronics ecosystem

  11. Computing with a canonical neural circuits model with pool normalization and modulating feedback.

    Science.gov (United States)

    Brosch, Tobias; Neumann, Heiko

    2014-12-01

    Evidence suggests that the brain uses an operational set of canonical computations like normalization, input filtering, and response gain enhancement via reentrant feedback. Here, we propose a three-stage columnar architecture of cascaded model neurons to describe a core circuit combining signal pathways of feedforward and feedback processing and the inhibitory pooling of neurons to normalize the activity. We present an analytical investigation of such a circuit by first reducing its detail through the lumping of initial feedforward response filtering and reentrant modulating signal amplification. The resulting excitatory-inhibitory pair of neurons is analyzed in a 2D phase-space. The inhibitory pool activation is treated as a separate mechanism exhibiting different effects. We analyze subtractive as well as divisive (shunting) interaction to implement center-surround mechanisms that include normalization effects in the characteristics of real neurons. Different variants of a core model architecture are derived and analyzed--in particular, individual excitatory neurons (without pool inhibition), the interaction with an inhibitory subtractive or divisive (i.e., shunting) pool, and the dynamics of recurrent self-excitation combined with divisive inhibition. The stability and existence properties of these model instances are characterized, which serve as guidelines to adjust these properties through proper model parameterization. The significance of the derived results is demonstrated by theoretical predictions of response behaviors in the case of multiple interacting hypercolumns in a single and in multiple feature dimensions. In numerical simulations, we confirm these predictions and provide some explanations for different neural computational properties. Among those, we consider orientation contrast-dependent response behavior, different forms of attentional modulation, contrast element grouping, and the dynamic adaptation of the silent surround in extraclassical

  12. Computation of a Single-phase Shell-Type Transformer Windings Forces Caused by Inrush and Short-circuit Currents

    Directory of Open Access Journals (Sweden)

    M. B.B. Sharifian

    2008-01-01

    Full Text Available This research studies the forces on the windings of transformer due to inrush current. These forces are compared with the corresponding forces due to short-circuit of the windings. Two-dimensional finite element computation of a single-phase shell-type transformer is carried out based on the maximum permissible inrush current value where its amplitude is the same as the rated short-circuit current. To verify the computation results, they are compared with those recently obtained using Artificial Neural Network (ANN.

  13. Development of Charge Sensitive Preamplifier and Readout Integrate Circuit Board for High Resolution Detector using ASIC Process

    International Nuclear Information System (INIS)

    - Design of discrete type charge sensitive amplifier for high resolution semi-conductor sensor - Design and develop the test board for the performance of charge sensitive amplifier with sensor - Performance of electrical test for the sensor and charge sensitive amplifier - Development of prototype 8 x 8 array type detector module - Noise equivalent charge test for the charge sensitive amplifier - Design and development of Micro SMD discrete type amplifier applying ASIC procedure - Development of Hybrid type charge sensitive amplifier including shape

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

    International Nuclear Information System (INIS)

    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. (paper)

  15. Application of PFMEA Method to Printed Circuit Board Component Assembly%PFMEA方法在印制板组件装配中的应用研究

    Institute of Scientific and Technical Information of China (English)

    奚慧; 张其政; 宋萍

    2014-01-01

    印制板组件装配涉及到多种器件和设备,工艺流程复杂多样,为保证产品的质量和可靠性,需要采取科学的方法研究装配过程。以印制板组件中通孔插装元器件的波峰焊接工艺流程为例,对焊接的潜在失效模式进行分析,将PFMEA这一可靠性研究工具引入其装配过程,寻找影响焊接质量的关键要素,从而为工艺改进提供依据。通过论证,证明PFMEA分析方式在工艺研究中能够将复杂抽象的问题简单化,为工艺研究提供了另一种较为科学、全面的分析手段。%Printed circuit board assembly involved in a variety of devices and many sets of equipment, process is complicated, in order to ensure product quality and reliability of assembly process, need to take the scientific method to research the process. Take the wave soldering process of through hole device in printed circuit board as example, analyze the potential failure mode of soldering, introduce the reliability research tool PFMEA to assembly process, find the key factors affecting the quality of soldering, so as to provide the basis for process improvement. PFMEA can simplify the complex and abstract problems in the process research, provide a more scientific and comprehensive analysis method for process.

  16. Computation Reduction for Statistical Analysis of the Effect of Nano-CMOS Variability on Integrated Circuits

    OpenAIRE

    Xie, Zheng

    2012-01-01

    The intrinsic atomistic variability of nano-scale integrated circuit (IC) technology must be taken into account when analysing circuit designs to predict likely yield. These ‘atomistic’ variabilities are random in nature and are so great that new circuit analysis techniques are needed which adopt a statistical treatment of the variability of device performances. Monte Carlo (MC) based statistical techniques aim to do this by analysing many randomized copies of the circuit. The randomization ...

  17. Benchmarking the CRBLASTER Computational Framework on the 350-MHz 49-core Maestro Development Board

    Science.gov (United States)

    Mighell, K. J.

    2012-09-01

    I describe the performance of the CRBLASTER computational framework on a 350-MHz 49-core Maestro Development Board (MBD). The 49-core Interim Test Chip (ITC) was developed by the U.S. Government and is based on the intellectual property of the 64-core TILE64 processor of the Tilera Corporation. The Maestro processor is intended for use in the high radiation environments found in space; the ITC was fabricated using IBM 90-nm CMOS 9SF technology and Radiation-Hardening-by-Design (RHDB) rules. CRBLASTER is a parallel-processing cosmic-ray rejection application based on a simple computational framework that uses the high-performance computing industry standard Message Passing Interface (MPI) library. CRBLASTER was designed to be used by research scientists to easily port image-analysis programs based on embarrassingly-parallel algorithms to a parallel-processing environment such as a multi-node Beowulf cluster or multi-core processors using MPI. I describe my experience of porting CRBLASTER to the 64-core TILE64 processor, the Maestro simulator, and finally the 49-core Maestro processor itself. Performance comparisons using the ITC are presented between emulating all floating-point operations in software and doing all floating point operations with hardware assist from an IEEE-754 compliant Aurora FPU (floating point unit) that is attached to each of the 49 cores. Benchmarking of the CRBLASTER computational framework using the memory-intensive L.A.COSMIC cosmic ray rejection algorithm and a computational-intensive Poisson noise generator reveal subtleties of the Maestro hardware design. Lastly, I describe the importance of using real scientific applications during the testing phase of next-generation computer hardware; complex real-world scientific applications can stress hardware in novel ways that may not necessarily be revealed while executing simple applications or unit tests.

  18. Display glass for low-loss and high-density optical interconnects in electro-optical circuit boards with eight optical layers.

    Science.gov (United States)

    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. PMID:26699042

  19. A Low-cost 4 Bit, 10 Giga-samples-per-second Analog-to-digital Converter Printed Circuit Board Assembly for FPGA-based Backends

    Science.gov (United States)

    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.

  20. The study of hybrid model identification,computation analysis and fault location for nonlinear dynamic circuits and systems

    Institute of Scientific and Technical Information of China (English)

    XIE Hong; HE Yi-gang; ZENG Guan-da

    2006-01-01

    This paper presents the hybrid model identification for a class of nonlinear circuits and systems via a combination of the block-pulse function transform with the Volterra series.After discussing the method to establish the hybrid model and introducing the hybrid model identification,a set of relative formulas are derived for calculating the hybrid model and computing the Volterra series solution of nonlinear dynamic circuits and systems.In order to significantly reduce the computation cost for fault location,the paper presents a new fault diagnosis method based on multiple preset models that can be realized online.An example of identification simulation and fault diagnosis are given.Results show that the method has high accuracy and efficiency for fault location of nonlinear dynamic circuits and systems.

  1. Multiple single-board-computer system for the KEK positron generator control

    Science.gov (United States)

    Nakahara, Kazuo; Abe, Isamu; Enomoto, Atsushi; Otake, Yuji; Urano, Takao

    1986-06-01

    The KEK positron generator is controlled by means of a distributed microprocessor network. The control system is composed of three kinds of equipment: device controllers for the linac equipment, operation management stations and a communication network. Individual linac equipment has its own microprocessor-based controller. A multiple single board computer (SBC) system is used for communication control and for equipment surveillance; it has a database containing communication and linac equipment status information. The linac operation management that should be the most soft part in the control system, is separated from the multiple SBC system and is carried out by work-stations. The principle that every processor executes only one task is maintained throughout the control system. This made the software architecture very simple.

  2. To Compare the Effects of Computer Based Learning and the Laboratory Based Learning on Students' Achievement Regarding Electric Circuits

    Science.gov (United States)

    Bayrak, Bekir; Kanli, Uygar; Ingec, Sebnem Kandil

    2007-01-01

    In this study, the research problem was: "Is the computer based physics instruction as effective as laboratory intensive physics instruction with regards to academic success on electric circuits 9th grade students?" For this research of experimental quality the design of pre-test and post-test are applied with an experiment and a control group.…

  3. Near-Threshold Computing and Minimum Supply Voltage of Single-Rail MCML Circuits

    Directory of Open Access Journals (Sweden)

    Ruiping Cao

    2014-01-01

    Full Text Available In high-speed applications, MOS current mode logic (MCML is a good alternative. Scaling down supply voltage of the MCML circuits can achieve low power-delay product (PDP. However, the current almost all MCML circuits are realized with dual-rail scheme, where the NMOS configuration in series limits the minimum supply voltage. In this paper, single-rail MCML (SRMCML circuits are described, which can avoid the devices configuration in series, since their logic evaluation block can be realized by only using MOS devices in parallel. The relationship between the minimum supply voltage of the SRMCML circuits and the model parameters of MOS transistors is derived, so that the minimum supply voltage can be estimated before circuit designs. An MCML dynamic flop-flop based on SRMCML is also proposed. The optimization algorithm for near-threshold sequential circuits is presented. A near-threshold SRMCML mode-10 counter based on the optimization algorithm is verified. Scaling down the supply voltage of the SRMCML circuits is also investigated. The power dissipation, delay, and power-delay products of these circuits are carried out. The results show that the near-threshold SRMCML circuits can obtain low delay and small power-delay product.

  4. Erica the Rhino: A Case Study in Using Raspberry Pi Single Board Computers for Interactive Art

    Directory of Open Access Journals (Sweden)

    Philip J. Basford

    2016-06-01

    Full Text Available Erica the Rhino is an interactive art exhibit created by the University of Southampton, UK. Erica was created as part of a city wide art trail in 2013 called “Go! Rhinos”, curated by Marwell Wildlife, to raise awareness of Rhino conservation. Erica arrived as a white fibreglass shell which was then painted and equipped with five Raspberry Pi Single Board Computers (SBC. These computers allowed the audience to interact with Erica through a range of sensors and actuators. In particular, the audience could feed and stroke her to prompt reactions, as well as send her Tweets to change her behaviour. Pi SBCs were chosen because of their ready availability and their educational pedigree. During the deployment, ‘coding clubs’ were run in the shopping centre where Erica was located, and these allowed children to experiment with and program the same components used in Erica. The experience gained through numerous deployments around the country has enabled Erica to be upgraded to increase reliability and ease of maintenance, whilst the release of the Pi 2 has allowed her responsiveness to be improved.

  5. Benchmarking Further Single Board Computers for Building a Mini Supercomputer for Simulation of Telecommunication Systems

    Directory of Open Access Journals (Sweden)

    Gábor Lencse

    2016-01-01

    Full Text Available Parallel Discrete Event Simulation (PDES with the conservative synchronization method can be efficiently used for the performance analysis of telecommunication systems because of their good lookahead properties. For PDES, a cost effective execution platform may be built by using single board computers (SBCs, which offer relatively high computation capacity compared to their price or power consumption and especially to the space they take up. A benchmarking method is proposed and its operation is demonstrated by benchmarking ten different SBCs, namely Banana Pi, Beaglebone Black, Cubieboard2, Odroid-C1+, Odroid-U3+, Odroid-XU3 Lite, Orange Pi Plus, Radxa Rock Lite, Raspberry Pi Model B+, and Raspberry Pi 2 Model B+. Their benchmarking results are compared to find out which one should be used for building a mini supercomputer for parallel discrete-event simulation of telecommunication systems. The SBCs are also used to build a heterogeneous cluster and the performance of the cluster is tested, too.

  6. 废弃电路板中非金属组分的回收利用%Recycling of non-metallic fractions from waste printed circuit boards

    Institute of Scientific and Technical Information of China (English)

    刘旸; 刘静欣; 江晓健; 郭学益

    2016-01-01

    废弃电路板是电子废弃物的重要组成部分。目前工业生产及工艺开发多针对极具经济回收价值的电路板金属组分。然而,占电路板质量分数70%的非金属组分却关注较少。文章分析了废弃电路板非金属组分的组成及其有害组分,其含有树脂及玻璃纤维等有价成分和溴、夹杂重金属等污染环境的物质,其回收利用对于资源循环利用及环境保护均有重要意义。非金属组分回收利用主要有物理处理和化学处理2种技术:物理处理技术主要将非金属组分用作结构材料填料、塑料改性剂和建筑材料改性剂;化学处理技术通过焚烧将非金属组分用作燃料和熔剂或通过热解回收或溶剂分解回收可将非金属组分转化为化工产品。这2种技术在非金属组分资源化利用上各有优势,都已有部分工业化应用。%Waste printed circuit boards (WPCBs) are important parts in the electronic waste. Nowadays, recov-ering metals from WPCBs are developed but non-metallic fractions which accounts for 70% of waste printed circuit boards have not been effectively utilized. The non-metallic fractions and hazards in waste printed cir-cuit boards were analyzed in this paper. The results show that resins and glass fiber in non-metallic fractions can be recycled and bromine and heavy metals could pollute environment. Recovering non-metallic fractions are important to recycling and environment, which can be divided into physical recycling technology and chemical recycling technology, with the formal using non-metallic fractions as the filler materials, plastic modifier or building material modifiers, and the latter using non-metallic fractions as the fuel and smelting flux through incineration or convert non-metallic fractions into chemical products through pyrolysis or solvent decomposition. Both technologies have their own advantages in resource utilization of non-metallic fractions, and partly

  7. Computing with networks of spiking neurons on a biophysically motivated floating-gate based neuromorphic integrated circuit.

    Science.gov (United States)

    Brink, S; Nease, S; Hasler, P

    2013-09-01

    Results are presented from several spiking network experiments performed on a novel neuromorphic integrated circuit. The networks are discussed in terms of their computational significance, which includes applications such as arbitrary spatiotemporal pattern generation and recognition, winner-take-all competition, stable generation of rhythmic outputs, and volatile memory. Analogies to the behavior of real biological neural systems are also noted. The alternatives for implementing the same computations are discussed and compared from a computational efficiency standpoint, with the conclusion that implementing neural networks on neuromorphic hardware is significantly more power efficient than numerical integration of model equations on traditional digital hardware.

  8. Computer simulations of stimulus dependent state switching in basic circuits of bursting neurons

    Science.gov (United States)

    Rabinovich, Mikhail; Huerta, Ramón; Bazhenov, Maxim; Kozlov, Alexander K.; Abarbanel, Henry D. I.

    1998-11-01

    We investigate the ability of oscillating neural circuits to switch between different states of oscillation in two basic neural circuits. We model two quite distinct small neural circuits. The first circuit is based on invertebrate central pattern generator (CPG) studies [A. I. Selverston and M. Moulins, The Crustacean Stomatogastric System (Springer-Verlag, Berlin, 1987)] and is composed of two neurons coupled via both gap junction and inhibitory synapses. The second consists of coupled pairs of interconnected thalamocortical relay and thalamic reticular neurons with both inhibitory and excitatory synaptic coupling. The latter is an elementary unit of the thalamic networks passing sensory information to the cerebral cortex [M. Steriade, D. A. McCormick, and T. J. Sejnowski, Science 262, 679 (1993)]. Both circuits have contradictory coupling between symmetric parts. The thalamocortical model has excitatory and inhibitory connections and the CPG has reciprocal inhibitory and electrical coupling. We describe the dynamics of the individual neurons in these circuits by conductance based ordinary differential equations of Hodgkin-Huxley type [J. Physiol. (London) 117, 500 (1952)]. Both model circuits exhibit bistability and hysteresis in a wide region of coupling strengths. The two main modes of behavior are in-phase and out-of-phase oscillations of the symmetric parts of the network. We investigate the response of these circuits, while they are operating in bistable regimes, to externally imposed excitatory spike trains with varying interspike timing and small amplitude pulses. These are meant to represent spike trains received by the basic circuits from sensory neurons. Circuits operating in a bistable region are sensitive to the frequency of these excitatory inputs. Frequency variations lead to changes from in-phase to out-of-phase coordination or vice versa. The signaling information contained in a spike train driving the network can place the circuit into one or

  9. A Brief Discussion of the Research Situation of Disassembly Technology of Waste Printed Circuit Boards%浅谈印刷电路板拆解技术的研究现状

    Institute of Scientific and Technical Information of China (English)

    张晓娇; 李挺

    2015-01-01

    There exist lots of methods for the processing of printed circuit boards .Currently ,the recovery pro‐cessing of printed circuit boards is divided into three stages ,including disassembly and break ,material's gath‐ering and separation ,and product purification .The efficiency of resource utilization of the waste printed cir‐cuit boards is quite low .T herefore ,adopting the concept of circular economy and recycling recovery process‐ing is one of the ways to deal with printed circuit boards reasonably .In order to recycle the components on printed circuit boards ,it is necessary to disassemble components from PCB in good condition .Through the understanding of current processing technology of PCB ,this article puts forward a new processing direction of PCB ,w hich is of high efficiency and resource utilization rate .%指出了废弃印刷电路板的回收处理大体分为拆卸和破碎、物质富集分离、产品精制三个阶段,为了能够回收印刷电路板上的元器件,有必要对线路板上的元器件进行无损拆解。对国内外现有印刷电路板的处理处置技术进行了分析,提出了一种新的、高效、高资源利用率的线路板处理处置方向。

  10. Anti-vibration Optimization Design of Printed Circuit Board Based on Modal Analysis%基于模态分析的印制电路板抗振优化设计

    Institute of Scientific and Technical Information of China (English)

    陈康; 张雷; 胡晓吉

    2014-01-01

    To ensure a sufficiently high natural frequency of printed circuit board can effectively improve the anti -vibration capa-bility of the printed circuit board for .Two typical sizes of printed circuit board ( PCB) which are 3U and 6U are taken for exam-ple, their finite element models are established , and their natural frequencies are obtained by modal analysis .Optimal installation solutions are designed for 3U and 6U boards to solve their problems of low natural frequencies .The results show that the optimal installation solutions are easy to implement , they can significantly increase the natural frequencies for 3U and 6U boards and en-hance the anti-vibration reliability , at the same time the installation solutions meet the needs of circuit design .%保证印制电路板足够高的固有频率可有效提高印制电路板的抗振能力。以3U和6U两种典型尺寸的印制电路板为例,分别建立有限元模型,通过模态分析得到其各阶固有频率。针对印制电路板固有频率偏低的问题,分别对3U和6U板卡设计优化安装方案。模态分析表明,这些优化安装方案易于实现,可显著提高这2种板卡的固有频率,增强抗振能力,提高可靠性,同时考虑了电路设计的需要。

  11. Support for the Core Research Activities and Studies of the Computer Science and Telecommunications Board (CSTB)

    Energy Technology Data Exchange (ETDEWEB)

    Jon Eisenberg, Director, CSTB

    2008-05-13

    The Computer Science and Telecommunications Board of the National Research Council considers technical and policy issues pertaining to computer science (CS), telecommunications, and information technology (IT). The functions of the board include: (1) monitoring and promoting the health of the CS, IT, and telecommunications fields, including attention as appropriate to issues of human resources and funding levels and program structures for research; (2) initiating studies involving CS, IT, and telecommunications as critical resources and sources of national economic strength; (3) responding to requests from the government, non-profit organizations, and private industry for expert advice on CS, IT, and telecommunications issues; and to requests from the government for expert advice on computer and telecommunications systems planning, utilization, and modernization; (4) fostering interaction among CS, IT, and telecommunications researchers and practitioners, and with other disciplines; and providing a base of expertise in the National Research Council in the areas of CS, IT, and telecommunications. This award has supported the overall operation of CSTB. Reports resulting from the Board's efforts have been widely disseminated in both electronic and print form, and all CSTB reports are available at its World Wide Web home page at cstb.org. The following reports, resulting from projects that were separately funded by a wide array of sponsors, were completed and released during the award period: 2007: * Summary of a Workshop on Software-Intensive Systems and Uncertainty at Scale * Social Security Administration Electronic Service Provision: A Strategic Assessment * Toward a Safer and More Secure Cyberspace * Software for Dependable Systems: Sufficient Evidence? * Engaging Privacy and Information Technology in a Digital Age * Improving Disaster Management: The Role of IT in Mitigation, Preparedness, Response, and Recovery 2006: * Renewing U.S. Telecommunications

  12. A Study on Pyrolysis Behavior of Waste Printed Circuit Boards%不同废旧电路板的 TG 行为研究

    Institute of Scientific and Technical Information of China (English)

    王佐仑; 张航; 丁洁; 令狐文生

    2014-01-01

    The pyrolysis of different kinds of waste printed circuit boards ( PCBs ) was investigated through TG technology.The effects of pyrolysis temperature , flow rate of nitrogen and heating rate on the pyrolysis behavior of PCBs were studied.The results showed that the heating rate had remarkable effect on the pyrolysis process and lower heating rate was benefit of the pyrolyiss.The most pyrolysis process was occurred at about 330~700 ℃for all of PCBs.%用电路板做为研究对象,去除其电子元件和金属元件,用钳子分解为直径为3 mm左右的碎片。用热重-差热分析仪对其进行热解,考察了热解温度、气氛流速、升温速率对热解的影响。结果表明,升温速率为影响电路板热解最重要的因素,升温速率慢有利于电路板的热解,热解时间越久热解越完全,热解率随着气流速度的增大而先上升后下降。废旧电路板的主要热解温度在350~700℃。

  13. Co-recycling of acrylonitrile-butadiene-styrene waste plastic and nonmetal particles from waste printed circuit boards to manufacture reproduction composites.

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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. (note)

  15. Recycling of waste printed circuit boards with simultaneous enrichment of special metals by using alkaline melts: A green and strategically advantageous solution.

    Science.gov (United States)

    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. PMID:26775099

  16. Circuits on Cylinders

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro; Vinay, V

    2006-01-01

    We consider the computational power of constant width polynomial size cylindrical circuits and nondeterministic branching programs. We show that every function computed by a Pi2 o MOD o AC0 circuit can also be computed by a constant width polynomial size cylindrical nondeterministic branching...... program (or cylindrical circuit) and that every function computed by a constant width polynomial size cylindrical circuit belongs to ACC0....

  17. A general computer program for the fast dynamic analysis. The case of pipe-circuits

    International Nuclear Information System (INIS)

    The dynamics of pipe circuits containing flowing liquids, and in particular the case of an accident, present a problem for the safety of nuclear power plants. The rupture of the pipe involves a depressurization in the circuit and this is followed by a whipping action of the broken pipe. More generally the situations which involve the rapid speeding up of fluids in circuits, with or without fluid-structure coupling, may be treated by PLEXUS. The results for the rigid-pipe case, incorporating the most characteristic situations, will be shown first. The second part will present some preliminary calculation results for the complete system with deformable pipe circuits and taking into account the fluid-structure coupling

  18. Evolutionary Synthesis of Cube Root Computational Circuit Using Graph Hybrid Estimation of Distribution Algorithm

    OpenAIRE

    J. Slezak; J. Petrzela

    2014-01-01

    The paper is focused on evolutionary synthesis of analog circuit realization of cube root function using proposed Graph Hybrid Estimation of Distribution Algorithm. The problem of cube root function circuit realization was adopted to demonstrate synthesis capability of the proposed method. Individuals of the population of the proposed method which represent promising topologies are encoded using graphs and hypergraphs. Hybridization with local search algorithm was used. The proposed method em...

  19. Evolutionary Synthesis of Cube Root Computational Circuit Using Graph Hybrid Estimation of Distribution Algorithm

    Directory of Open Access Journals (Sweden)

    J. Slezak

    2014-04-01

    Full Text Available The paper is focused on evolutionary synthesis of analog circuit realization of cube root function using proposed Graph Hybrid Estimation of Distribution Algorithm. The problem of cube root function circuit realization was adopted to demonstrate synthesis capability of the proposed method. Individuals of the population of the proposed method which represent promising topologies are encoded using graphs and hypergraphs. Hybridization with local search algorithm was used. The proposed method employs univariate probabilistic model.

  20. 废弃电路板非金属粉末作为水泥增强材料的试验研究%Experiment on taking waste circuit board nonmetallic powder as cement augmentation material

    Institute of Scientific and Technical Information of China (English)

    谢俊; 刘卫东; 杨琴华; 霍晓凡

    2014-01-01

    In view of the problem that waste circuit board nonmetallic powder is difficult to deal with, based on the analysis of composition of waste circuit board nonmetal powder, the paper proposed to take it as a kind of reinforced material which is mixed into concrete and mortar.The experiment results show that the circuit board nonmetallic powder can increase obviously the early compressive strength of concrete and mortar,when non-metallic powder of one kind of fine powdery waste printed circuit boards is mixed at 16. 5%, the early compressive strength after three days increased by 22%.The compressive strength of mor-tar after also inhence after 28 days, so the nonmetallic powder can be used as a kind of cement reinforced material.%针对废弃电路板非金属粉末难以处理的问题,在分析了废弃电路板非金属粉末组成成分的基础上,提出了将其作为一种增强材料掺入到混凝土和砂浆中以增强混凝土和砂浆的强度。结果表明:废弃电路板非金属粉末对混凝土以及砂浆的早期抗压强度提高明显,A种细粉末状废弃电路板非金属粉末在掺量为16.5%时,3 d早期强度提高22%。对砂浆28 d抗压强度也有所提高,故非金属粉末可以作为水泥增强材料。

  1. Computation of fission product distribution in core and primary circuit of a high temperature reactor during normal operation

    International Nuclear Information System (INIS)

    The fission product release during normal operation from the core of a high temperature reactor is well known to be very low. A HTR-Modul-reactor with a reduced power of 170 MWth is examined under the aspect whether the contamination with Cs-137 as most important nuclide will be so low that a helium turbine in the primary circuit is possible. The program SPTRAN is the tool for the computations and siumlations of fission product transport in HTRs. The program initially developed for computations of accident events has been enlarged for computing the fission product transport under the conditions of normal operation. The theoretical basis, the used programs and data basis are presented followed by the results of the computations. These results are explained and discussed; moreover the consequences and future possibilities of development are shown. (orig./HP)

  2. Next Processor Module: A Hardware Accelerator of UT699 LEON3-FT System for On-Board Computer Software Simulation

    Science.gov (United States)

    Langlois, Serge; Fouquet, Olivier; Gouy, Yann; Riant, David

    2014-08-01

    On-Board Computers (OBC) are more and more using integrated systems on-chip (SOC) that embed processors running from 50MHz up to several hundreds of MHz, and around which are plugged some dedicated communication controllers together with other Input/Output channels. For ground testing and On-Board SoftWare (OBSW) validation purpose, a representative simulation of these systems, faster than real-time and with cycle-true timing of execution, is not achieved with current purely software simulators. Since a few years some hybrid solutions where put in place ([1], [2]), including hardware in the loop so as to add accuracy and performance in the computer software simulation. This paper presents the results of the works engaged by Thales Alenia Space (TAS-F) at the end of 2010, that led to a validated HW simulator of the UT699 by mid- 2012 and that is now qualified and fully used in operational contexts.

  3. Printed circuit for ATLAS

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    A printed circuit board made by scientists in the ATLAS collaboration for the transition radiaton tracker (TRT). This will read data produced when a high energy particle crosses the boundary between two materials with different electrical properties.

  4. Design and realization of a certain type of radio power supply circuit board detecting and teaching platform%某型电台电源板检测示教平台的设计与实现

    Institute of Scientific and Technical Information of China (English)

    刘桂云; 邵智超

    2012-01-01

    为达到某型电台电路板形象直观的示教、检测和故障诊断的目的,研究开发了某型指挥系统的检测示教平台.文中介绍了某型电台电源板检测示教平台的设计与实现方法,平台主要包括适配器和示教软件两个部分.实际应用表明,该平台运行稳定可靠,能大幅提高装备电路板教学的效率和水平,也为电路板的检测和故障诊断提供了一个途径.%A certain type of command and control system detecting and teaching platform is designed in order to realize clear display of the operation and implement the capability teaching detecting and fault diagnosis conveniently. This thesis which is a part of the program introduces design and realization of a certain type of radio power supply circuit board detecting and teaching platform. The platform consists of adapter and teaching software. The experiments indicate that the platform is reliable in the operation, can improve efficiency of circuit board teaching and provide a method for circuit board detecting and fault diagnosis.

  5. 改善印制电路板化学镀镍耐蚀性的研究进展%Research progress of improvement of corrosion resistance of electroless nickel coating on printed circuit board

    Institute of Scientific and Technical Information of China (English)

    冯立; 何为; 黄雨新; 何杰; 徐缓

    2013-01-01

    在印制电路板化学镀镍/金过程中,镍、金原子固有的结构特征使镍镀层极易被氧化腐蚀,从而影响镀层的可焊性。从化学镀Ni-P基多元合金,引入纳米粒子和稀土材料,以及化学镀Ni-B合金三方面,介绍了改善印制电路板化学镀镍层耐蚀性的研究现状。对印制电路板化学镀镍耐蚀性的改善方法提出了建议。%Oxidation corrosion of nickel coating occurs easily during the electroless nickel/gold plating process on the surface of printed circuit board because of the inherent structure features of nickel and gold atoms, thus affecting the solderability of coating. The research progress of improvement of corrosion resistance of electroless nickel coating on printed circuit board was introduced from three aspects including electroless Ni-P-based multicomponent alloy plating, introduction of nanoparticles and rare earth materials, and electroless Ni-B alloy. Some suggestions about improvement method of corrosion resistance of electroless nickel coating on printed circuit board were proposed.

  6. Single-board computer based control system for a portable Raman device with integrated chemical identification

    Science.gov (United States)

    Mobley, Joel; Cullum, Brian M.; Wintenberg, Alan L.; Shane Frank, S.; Maples, Robert A.; Stokes, David L.; Vo-Dinh, Tuan

    2004-06-01

    We report the development of a battery-powered portable chemical identification device for field use consisting of an acousto-optic tunable filter (AOTF)-based Raman spectrometer with integrated data processing and analysis software. The various components and custom circuitry are integrated into a self-contained instrument by control software that runs on an embedded single-board computer (SBC), which communicates with the various instrument modules through a 48-line bidirectional TTL bus. The user interacts with the instrument via a touch-sensitive liquid crystal display unit (LCD) that provides soft buttons for user control as well as visual feedback (e.g., spectral plots, stored data, instrument settings, etc.) from the instrument. The control software manages all operational aspects of the instrument with the exception of the power management module that is run by embedded firmware. The SBC-based software includes both automated and manual library searching capabilities, permitting rapid identification of samples in the field. The use of the SBC in tandem with the LCD touchscreen for interfacing and control provides the instrument with a great deal of flexibility as its function can be customized to specific users or tasks via software modifications alone. The instrument, as currently configured, can be operated as a research-grade Raman spectrometer for scientific applications and as a "black-box" chemical identification system for field use. The instrument can acquire 198-point spectra over a spectral range of 238-1620 cm-1, perform a library search, and display the results in less than 14 s. The operating modes of the instrument are demonstrated illustrating the utility and flexibility afforded the system by the SBC-LCD control module.

  7. Poster — Thur Eve — 08: Rotational errors with on-board cone beam computed tomography

    International Nuclear Information System (INIS)

    The focus of this study is on the Elekta XVI on-board cone beam computed tomography (CBCT) system. A rotational mismatch as large as 0.5° is observed between clockwise (CW) and counter-clockwise (CCW) CBCT scans. The error could affect non-isocentric treatments (e.g., lung SBRT and acoustic neuroma), as well as off-axis organs-at-risk. The error is caused by mislabeling of the projections with a lagging gantry angle, which is caused by the finite image acquisition time and delays in the imaging system. A 30 cm diameter cylindrical phantom with 5 mm diameter holes is used for the scanning. CW and CCW scans are acquired for five gantry speeds (360 to 120 deg./min.) on six linacs from three generations (MLCi, MLCi2, and Agility). Additional scans are acquired with different x-ray pulse widths for the same mAs. In the automated CBCT analysis (using ImageJ), the CW/CCW mismatch in a series of line profiles is identified and used to calculate the rotational error. Results are consistent among all linacs and indicate that the error varies linearly with gantry speed. The finite width of the x-ray pulses is a major but predictable contributor to the delay causing the error. For 40 ms pulses, the delay is 34 ± 1 ms. A simple solution applied in our clinic is adjusting the gantry angle offset to make the CCW one-minute scans correct. A more involved approach we are currently investigating includes adjustments of pulse width and mA, resulting in focal spot changes, with potential impact on image quality

  8. Poster — Thur Eve — 08: Rotational errors with on-board cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ali, E. S. M. [The Ottawa Hospital Cancer Centre, Ottawa (Canada); Webb, R. [Elekta, Ottawa (Canada); Nyiri, B. [The Ottawa Hospital Cancer Centre, Ottawa (Canada); University of Ottawa, Ottawa (Canada)

    2014-08-15

    The focus of this study is on the Elekta XVI on-board cone beam computed tomography (CBCT) system. A rotational mismatch as large as 0.5° is observed between clockwise (CW) and counter-clockwise (CCW) CBCT scans. The error could affect non-isocentric treatments (e.g., lung SBRT and acoustic neuroma), as well as off-axis organs-at-risk. The error is caused by mislabeling of the projections with a lagging gantry angle, which is caused by the finite image acquisition time and delays in the imaging system. A 30 cm diameter cylindrical phantom with 5 mm diameter holes is used for the scanning. CW and CCW scans are acquired for five gantry speeds (360 to 120 deg./min.) on six linacs from three generations (MLCi, MLCi2, and Agility). Additional scans are acquired with different x-ray pulse widths for the same mAs. In the automated CBCT analysis (using ImageJ), the CW/CCW mismatch in a series of line profiles is identified and used to calculate the rotational error. Results are consistent among all linacs and indicate that the error varies linearly with gantry speed. The finite width of the x-ray pulses is a major but predictable contributor to the delay causing the error. For 40 ms pulses, the delay is 34 ± 1 ms. A simple solution applied in our clinic is adjusting the gantry angle offset to make the CCW one-minute scans correct. A more involved approach we are currently investigating includes adjustments of pulse width and mA, resulting in focal spot changes, with potential impact on image quality.

  9. Computer simulation of short-circuiting transfer welding under waveform control on inverter power source

    Institute of Scientific and Technical Information of China (English)

    Yang Lijun; Feng Shengqiang; Dong Tianshun; Li Huan

    2007-01-01

    A simulation model is introduced about the non-linearity process of short-circuiting transfer in CO2 arc welding for displaying the interaction between the inverter power source and welding arc under waveform control. In the simulation model, the feedback signals of current and voltage are taken respectively at the different phase in a short circuit periodic time and applied to the PWM(pulse width modulation) module in a model of inverter power source to control the output of power source. The simulation operation about the dynamic process of CO2 short-circuiting transfer welding is implemented on the founded simulation model with a peak arc current of 400 A and a peak voltage of 35 V, producing the dynamic arc waveforms which can embody the effect of inverter harmonic wave. The simulating waveforms are close to that of welding experiments.

  10. Minimal-flow xenon and semiclosed circuit anesthesia for computed tomographic measurement of local cerebral blood flow (LCBF)

    International Nuclear Information System (INIS)

    For the purpose of decreasing the volume of expensive xenon, anesthesia with minimal-flow xenon and semiclosed circuit were induced for computed tomographic LCBF measurement. Eighteen patients with ischemic cerebral disease were studied. Xenon inhalation programs were subdivided into three groups, each of them consisted of 6 patients. The formula for calculating fresh gas flow for low flow semiclosed circuit was introduced according to Shimoji's which was based on the original formula of Foldes. O2 concentration in circuit was predicted to be 25%. Mean xenon uptake for initial 20 minutes was predicted to be125 ml/min. or 360 ml/min. The first group started xenon inhalation during pure xenon inflow into semic losed circuit for two minutes and followed by about 68% xenon in O2 inhalation for 23 munites. FXe and VXe were fixed at 700 ml/min and 360 ml/min respectively. The second group was set at the same conditions as the first group except FXe and VXe as shown in Fig.2. The third group inhaled about 63% xenon-oxygen mixture affer four minutes pure xenon inflow. Xenon concentrations in trachea, carotid artery and jugular vein were estimated from the conversion into equivalent enhancement in CT units for every four minutes on line. Fig. 3 shows the O2 concentration change in semiclosed circuit, endtidal CO2 tension and percent change of mean arterial pressure. After 20 minutes xenon inhalation O2 concentration in each group closed to 25% which was predicted O2 concentration of the third group closed more rapidly to 25% than other groups. Normocarbia and stable hemodynamics could be confirmed throughout the procedures in each group. Fig. 5 shows xenon washin curves in trachea and xenon concentration change in carotid artery and jugular vein during xenon inhalation. The washin curves in trachea are quite different in each group. (J.P.N.)

  11. 空气氧化—氨浸出废旧电路板中的铜%Ammonia-Ammonium Sulfate Copper Leaching from Waste Printed Circuit Boards

    Institute of Scientific and Technical Information of China (English)

    张有新; 李静; 潘发芳

    2013-01-01

    A novel hydrometallurgical process of copper recovery from waste printed circuit boards was introduced. In this process, air was blown into solution as oxidant for copper leaching in NH3-(NH4)2SO4-H2O system, while leaching residue was treated by physical method. The effects of ammonia and ammonium sulfate concentration, ratio of solid to liquid, leaching temperature, air flow and leaching time on copper leaching rate were investigated. The results show that copper leaching rate is up to 96. 67% under the following optimum conditions including ammonia concentration of 2 mol/L, ammonium sulfate concentration of 2 mol/L, ratio of solid to liquid of 1 : 20, leaching temperature of 25 ℃ , air flow of 8 m3/h and leaching time of 4 h.%提出了在氨水—硫酸铵体系下鼓入空气浸出废旧电路板中铜的新工艺.考察了氨水浓度、硫酸铵浓度、固液比、反应温度、通入空气流量和浸出时间对铜浸出率的影响.结果表明,在下述最佳浸出条件下,渣计铜浸出率达到96.67%:氨水浓度2 mol/L,硫酸铵浓度2 mol/L,固液比1∶20,反应温度25℃、通入空气量8 m3/h、浸出时间4h.

  12. A new technology for separation and recovery of materials from waste printed circuit boards by dissolving bromine epoxy resins using ionic liquid

    International Nuclear Information System (INIS)

    Highlights: ► WPCBs were heated in [EMIM+][BF4−] for recovering solider at 240 °C. ► The bromine epoxy resins in WPCBs were all dissolved in [EMIM+][BF4−] at 260 °C. ► Used [EMIM+][BF4−] is treated by water to obtain regeneration. - Abstract: 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.

  13. Fault Detection and Diagnosis Technology Research for the Instrumentation and Control Circuit Board of the Nuclear Power Plant%核电厂仪控板件故障检测与诊断技术研究

    Institute of Scientific and Technical Information of China (English)

    王健; 王江波; 邱建文

    2014-01-01

    In the nuclear power plant , instrumentation and control circuit boards are important parts of the in-strumentation and control system .The performances of this kind of circuit boards have a direct impact on the safety ,reliability and economic efficiency of the nuclear power plant .Based on in-circuit test technology ,fault detection and diagnosis technology of the instrumentation and control circuit boards are discussed by this work . This paper introduces the overseas experience ,the main function and development process of ICT .In addition , theof the test data is also studied .This fault detection and diagnosis technology plays an important role in im -proving the safety level of the nuclear power plant operation .%仪控板件是核电厂仪控系统的重要组成部分,仪控板件的性能对核电厂能否安全、可靠、经济的运行有直接影响。本工作以在线测试为基础,对核电厂仪控板件的故障检测及其诊断技术进行了探讨;介绍了国外同行在该领域的相关经验和在线测试的主要功能、开发流程以及测试数据的分析方法,该故障检测与诊断技术对提高核电厂的安全运行水平有重要作用。

  14. 重构印刷电路板的装配过程:一个案例研究%REENGINEERING THE ASSEMBLY PROCESSES OF PRINTED CIRCUIT BOARDS:A CASE STUDY

    Institute of Scientific and Technical Information of China (English)

    朱秀文; 左明健

    2000-01-01

    This paper reports the reengineering of the assembly processes of printed circuit boards (PCBs) used in computers.The new designed assembly processes are quite different from the traditional ones,and the business performance is dramatically improved through establishing parallel workstations,off-line workstation,merging workstations and organizing a small teamwork who cooperates in stations."ITHINK",a software package of business process reengineering (BPR),was used to analyze the current processes and create new processes.ITHINK is a powerful tool of BPR in modeling business processes,"soft" variables and conducting sensitivity analysis.The new assembly processes were tested over a period of 8 hours simulation.The results show that the new processes can increase throughput by 80% with only requiring less additional resources.The throughput can increase further by 17.5% when a small teamwork cooperates in some stations.%研究计算机用印刷电路板装配过程的重构.新设计的装配过程通过建立并行和线外工作站、合并某些工作站及组织联合操作的团队,显著地改善了企业绩效.在8 h的模拟周期内对新的装配过程进行了实验.结果表明,在增加少量资源的情况下,新的装配过程使产量增加80%.一个小团队在某些工作站联合操作,产量可进一步增加17.5%.

  15. Software-Controlled Next Generation Optical Circuit Switching for HPC and Cloud Computing Datacenters

    OpenAIRE

    Muhammad Imran; Martin Collier; Pascal Landais; Kostas Katrinis

    2015-01-01

    In this paper, we consider the performance of optical circuit switching (OCS) systems designed for data center networks by using network-level simulation. Recent proposals have used OCS in data center networks but the relatively slow switching times of OCS-MEMS switches (10–100 ms) and the latencies of control planes in these approaches have limited their use to the largest data center networks with workloads that last several seconds. Herein, we extend the applicability and generality of the...

  16. Circuit analysis for dummies

    CERN Document Server

    Santiago, John

    2013-01-01

    Circuits overloaded from electric circuit analysis? Many universities require that students pursuing a degree in electrical or computer engineering take an Electric Circuit Analysis course to determine who will ""make the cut"" and continue in the degree program. Circuit Analysis For Dummies will help these students to better understand electric circuit analysis by presenting the information in an effective and straightforward manner. Circuit Analysis For Dummies gives you clear-cut information about the topics covered in an electric circuit analysis courses to help

  17. 废弃线路板中重金属形态分布特征%Speciation Distribution Characters of Heavy Metals in Waste Printed Circuit Boards

    Institute of Scientific and Technical Information of China (English)

    赵国华; 罗兴章; 黄卓辉; 冯景伟; 郑正; 高顺枝; 聂耳; 倪利晓

    2009-01-01

    The environmental availability of heavy metals from the waste printed circuit boards (PCBs) were studied through BCR's three-stage extraction procedures from EU and Tessier's five sequential extraction procedures. The results show that the heavy metal extraction rates with BCR's procedures are higher than that with Tessier' s from waste PCBs. There are significant differences in fraction distributions of heavy metals in PCBs. The speciation of Ni in the PCBs exists mainly in residual forms and has little effect on the environment. The percentage of acidic extractable forms with BCR's method and the total amount of exchangeable and carbonate which bound for Tessier's procedure of Pb and Zn are high, in the South China, the two metals are more easily released by acid rain. Acidic extractable forms of Cu is the main speciation in PCBs with BCR's extraction procedures, while the percentage of Fe-Mn oxides- bound of Cu is the highest with Tessier's procedures, though the result is not agree consistent, due to the high content of Cu in PCBs, the harm of Cu from PCBs could not be neglected.%通过BCR3态连续提取方法和Tessier 5步连续提取方法,对某废弃线路板中重金属的赋存形态进行研究.结果表明,BCR连续提取法对废弃线路板中重金属的提取率比Tessier连续提取方法高.废弃线路板中Cu、Pb、Zn和Ni各形态分布差别很大.BCR和Tessier连续提取方法结果均表明废弃线路板中Ni主要是以残渣态存在,对环境的污染风险小;而Pb和Zn主要以酸可提取态或者碳酸盐态和可交换态存在,在南方酸雨环境中容易溶出;BCR和Tessier连续提取方法对Cu的活性评价不一致,但是由于废弃线路板中Cu总量高,对环境的影响不可忽视.

  18. Leaching of Au, Ag, and Pd from waste printed circuit boards of mobile phone by iodide lixiviant after supercritical water pre-treatment

    International Nuclear Information System (INIS)

    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

  19. Leaching of Au, Ag, and Pd from waste printed circuit boards of mobile phone by iodide lixiviant after supercritical water pre-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Xiu, Fu-Rong, E-mail: xiu_chem@hotmail.com [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108 (China); Qi, Yingying [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108 (China); Zhang, Fu-Shen [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    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.

  20. Dynamic spike threshold and nonlinear dendritic computation for coincidence detection in neuromorphic circuits.

    Science.gov (United States)

    Hsu, Chih-Chieh; Parker, Alice C

    2014-01-01

    We present an electronic cortical neuron incorporating dynamic spike threshold and active dendritic properties. The circuit is simulated using a carbon nanotube field-effect transistor SPICE model. We demonstrate that our neuron has lower spike threshold for coincident synaptic inputs; however when the synaptic inputs are not in synchrony, it requires larger depolarization to evoke the neuron to fire. We also demonstrate that a dendritic spike is key to precisely-timed input-output transformation, produces reliable firing and results in more resilience to input jitter within an individual neuron.

  1. Software-Controlled Next Generation Optical Circuit Switching for HPC and Cloud Computing Datacenters

    Directory of Open Access Journals (Sweden)

    Muhammad Imran

    2015-11-01

    Full Text Available In this paper, we consider the performance of optical circuit switching (OCS systems designed for data center networks by using network-level simulation. Recent proposals have used OCS in data center networks but the relatively slow switching times of OCS-MEMS switches (10–100 ms and the latencies of control planes in these approaches have limited their use to the largest data center networks with workloads that last several seconds. Herein, we extend the applicability and generality of these studies by considering dynamically changing short-lived circuits in software-controlled OCS switches, using the faster switching technologies that are now available. The modelled switch architecture features fast optical switches in a single hop topology with a centralized, software-defined optical control plane. We model different workloads with various traffic aggregation parameters to investigate the performance of such designs across usage patterns. Our results show that, with suitable choices for the OCS system parameters, delay performance comparable to that of electrical data center networks can be obtained.

  2. 生物湿法冶金技术回收废弃线路板中有价金属的研究进展%Review on recovering precious metals from wasted circuit board by bio-hydrometallurgy technology

    Institute of Scientific and Technical Information of China (English)

    曾伟民; 朱海珍; 叶子婕; 夏明晨; 喻子凌; 王新天

    2013-01-01

    The quantity of circuit board produced and abandoned has increased with the development of electronics industry. The characteristics of pyrometallurgical recovery, mechanical recovery and wet recovery, such as low recovery ratio, high cost and environmental pollution fails to recover the precious metals from wasted circuit board. This article discusses the feasibility and economic value of precious metals recovery from wasted circuit board by bio-hydrometallurgy by the sequence of dismantling-broken-biological leaching-follow-up treatment. The physiological and biochemical properties of the metallurgical microbials at the medium temperature, moderate thermophilic and moderate thermophilic are introduced respectively. The application prospect of the recovering precious metals from wasted circuit board by bio-hydrometallurgy technology is forecasted.%  随着电子工业的发展,线路板的生产量和废弃量日益增加。传统的火法回收、机械回收、湿法回收等废弃线路板的处理方法金属回收率低、成本高,且极易造成环境污染,不能很好地回收线路板中的有价金属。文中论述了采用生物湿法冶金技术通过拆解-破碎-生物浸出-后续处理4个步骤回收废弃线路板中有价金属的可行性以及该方法能够带来的巨大经济效益,介绍了常用的中温、中等嗜热、极度嗜热冶金微生物的生理生化性质。最后展望了生物湿法冶金技术在未来废弃线路板高效回收方面的应用前景。

  3. Protected quantum computation with multiple resonators in ultrastrong coupling circuit QED

    CERN Document Server

    Nataf, Pierre

    2011-01-01

    We investigate theoretically the dynamical behavior of a qubit obtained with the two ground eigenstates of an ultrastrong coupling circuit-QED system consisting of a finite number of Josephson fluxonium atoms inductively coupled to a transmission line resonator. We show an universal set of quantum gates by using multiple transmission line resonators (each resonator represents a single qubit). We discuss the intrinsic 'anisotropic' nature of noise sources for fluxonium artificial atoms. Through a master equation treatment with colored noise and manylevel dynamics, we prove that, for a general class of anisotropic noise sources, the coherence time of the qubit and the fidelity of the quantum operations can be dramatically improved in an optimal regime of ultrastrong coupling, where the ground state is an entangled photonic 'cat' state.

  4. The Design and Research of Device for Disassembly and Recycling of the Deserted Circuit Boards%废弃电路板拆解回收装置的设计与研究

    Institute of Scientific and Technical Information of China (English)

    刘林青; 张旻媛; 程羽佳; 邬强; 刘叶

    2014-01-01

    This paper is aimed at the shortcomings of the device for disassembly and recycling of the deserted circuit board which has alarge destruction for the electronic components while dismantle them, and thee fficiency of dismantling is not very high, in order to solve these problems the authors design a new method. According to the existing survey and study of the deserted circuit board’s disassembly and recycling devices, the authors designa method which combine semi-automaticdevice and automatic todisassemble the circuit boards, the further discussion is the advantages of this design hat compared with the traditional device, and interpret the further optimized about the deserted circuit board’s disassembly and recycling device. The method which mentioned in this paper can dismantle and recycle the deserted circuit board efifciently, and its operation is much lfexibly and simply.%本文针对已有的拆卸装置对电子元件拆除破坏性较大、拆除率不高等缺点提出了一种面向高校的废弃电路板拆解回收的设计方法。根据对已有的废弃电路板拆解回收装置的调查与研究,本文设计出了一种采用人工半自动添装与全自动分离相结合的办法对电路板进行拆解,进一步探讨了该装置与传统装置相比所具有的优势,并对该废弃电路板绿色拆解回收装置的继续优化进行了阐述。本文采用的方法可实现废弃电路板的高效拆解与回收,具有操作灵活、简单等特点。

  5. Signal-to-Noise Ratio Measures Efficacy of Biological Computing Devices and Circuits

    OpenAIRE

    Beal, Jacob

    2015-01-01

    Engineering biological cells to perform computations has a broad range of important potential applications, including precision medical therapies, biosynthesis process control, and environmental sensing. Implementing predictable and effective computation, however, has been extremely difficult to date, due to a combination of poor composability of available parts and of insufficient characterization of parts and their interactions with the complex environment in which they operate. In this pap...

  6. Signal-to-Noise Ratio Measures Efficacy of Biological Computing Devices and Circuits

    OpenAIRE

    Jacob eBeal

    2015-01-01

    Engineering biological cells to perform computations has a broad range of important potential applications, including precision medical therapies, biosynthesis process control, and environmental sensing. Implementing predictable and effective computation, however, has been extremely difficult to date, due to a combination of poor composability of available parts and of insufficient characterization of parts and their interactions with the complex environment in which they operate. In this p...

  7. Heterogeneous photonic integrated circuits and their applications in computing, networking, and imaging

    Science.gov (United States)

    Yoo, S. J. Ben

    2014-03-01

    We discuss heterogeneous integrations and their impacts on computing, networking, and imaging applications. We will review photonic integration technologies including silicon, InP, GaAs, SiO2, Si3N4, and magneto-optical materials such as YIG and BIG. We will address new architectures, new capabilities, and performance enhancement brought into computing, networking, and imaging architectures through heterogeneous photonic integration.

  8. An Intelligent and Fast Chaotic Encryption Using Digital Logic Circuits for Ad-Hoc and Ubiquitous Computing

    Directory of Open Access Journals (Sweden)

    Ankur Khare

    2016-05-01

    Full Text Available Delays added by the encryption process represent an overhead for smart computing devices in ad-hoc and ubiquitous computing intelligent systems. Digital Logic Circuits are faster than other computing techniques, so these can be used for fast encryption to minimize processing delays. Chaotic Encryption is more attack-resilient than other encryption techniques. One of the most attractive properties of cryptography is known as an avalanche effect, in which two different keys produce distinct cipher text for the same information. Important properties of chaotic systems are sensitivity to initial conditions and nonlinearity, which makes two similar keys that generate different cipher text a source of confusion. In this paper a novel fast and secure Chaotic Map-based encryption technique using 2’s Compliment (CET-2C has been proposed, which uses a logistic map which implies that a negligible difference in parameters of the map generates different cipher text. Cryptanalysis of the proposed algorithm shows the strength and security of algorithm and keys. Performance of the proposed algorithm has been analyzed in terms of running time, throughput and power consumption. It is to be shown in comparison graphs that the proposed algorithm gave better results compare to different algorithms like AES and some others.

  9. Circuit analysis I with Matlab computing and Simulink/SimPower systems modeling

    CERN Document Server

    Karris, Steven

    2009-01-01

    This text is an introduction to the basic principles of electrical engineering. It is intended for all engineering majors and presumes knowledge of first year differential and integral calculus and physics. Contains with real-world examples and problem supplemented with MATLAB computations, and Simulink/SimPower models.

  10. Value Constraint and Monotone circuit

    OpenAIRE

    Kobayashi, Koji

    2012-01-01

    This paper talks about that monotone circuit is P-Complete. Decision problem that include P-Complete is mapping that classify input with a similar property. Therefore equivalence relation of input value is important for computation. But monotone circuit cannot compute the equivalence relation of the value because monotone circuit can compute only monotone function. Therefore, I make the value constraint explicitly in the input and monotone circuit can compute equivalence relation. As a result...

  11. Automated design of analog and high-frequency circuits a computational intelligence approach

    CERN Document Server

    Liu, Bo; Fernández, Francisco V

    2014-01-01

    Computational intelligence techniques are becoming more and more important for automated problem solving nowadays. Due to the growing complexity of industrial applications and the increasingly tight time-to-market requirements, the time available for thorough problem analysis and development of tailored solution methods is decreasing. There is no doubt that this trend will continue in the foreseeable future. Hence, it is not surprising that robust and general automated problem solving methods with satisfactory performance are needed.

  12. Do Computer Simulations Allow a Better Understanding of Basic Electrical Circuits than Real Lab Experiments?

    CERN Document Server

    Schmekel, Bjoern S

    2010-01-01

    Several Authors have demonstrated that substituting computer simulations for real experiments conducted in a lab may help to improve students' understanding of the material. In the present work we try to understand the reasons for this intriguing finding and investigate possible prerequisites necessary to achieve this outcome. The study was conducted in an introductory college-level physics class in Germany. All simulations were performed using PSPICE.

  13. Starting with Ubicomp: using the SenseBoard to introduce computing

    OpenAIRE

    Richards, Michael; Petre, Marian; Bandara, Arosha

    2012-01-01

    In this paper, we describe a new undergraduate module for novice students conducted entirely through distance learning: My Digital Life (TU100). The module has been designed to lower the barriers to creating programs that interact with the world; TU100’s materials have been designed to excite, encourage, reassure and support learners who explore the novel topic of ubiquitous computing through playful experimentation. It introduces the fundamentals of computing by giving students the capabilit...

  14. 'Micro-8' micro-computer system

    International Nuclear Information System (INIS)

    The micro-computer Micro-8 system has been developed to organize a data exchange network between various instruments and a computer group including a large computer system. Used for packet exchangers and terminal controllers, the system consists of ten kinds of standard boards including a CPU board with INTEL-8080 one-chip-processor. CPU architecture, BUS architecture, interrupt control, and standard-boards function are explained in circuit block diagrams. Operations of the basic I/O device, digital I/O board and communication adapter are described with definitions of the interrupt ramp status, I/O command, I/O mask, data register, etc. In the appendixes are circuit drawings, INTEL-8080 micro-processor specifications, BUS connections, I/O address mappings, jumper connections of address selection, and interface connections. (author)

  15. The Classroom, Board Room, Chat Room, and Court Room: School Computers at the Crossroads.

    Science.gov (United States)

    Stewart, Michael

    2000-01-01

    In schools' efforts to maximize technology's benefits, ethical considerations have often taken a back seat. Computer misuse is growing exponentially and assuming many forms: unauthorized data access, hacking, piracy, information theft, fraud, virus creation, harassment, defamation, and discrimination. Integrated-learning activities will help…

  16. Study on Recycling of Non-metal Materials of Different Types of Waste Printed Circuit Boards%各类废弃印刷线路板非金属材料回收研究

    Institute of Scientific and Technical Information of China (English)

    管传金; 王景伟; 王静荣; 李秀丽; 周玉林

    2011-01-01

    The thermosetting epoxy resin contained in the non-metal powders of waste printed circuit boards could be decomposed in nitric acid.Seven types of non-metal powders of waste printed circuit boards were selected to measure the metal contents and glass fibers contents.The results revealed that the non-metal powders contained a small amount of metal residues and that the contents of glass fibers in seven types of PCBs non-metal powders were also different.Little glass fibers or no glass fibers were found in the paper-based PCBs.The relationship between the yields of recovered epoxy resins and reaction time was discussed.SEM and FT-IR were employed to characterize the recovering epoxy resins and glass fibers.%废弃印刷电路板(Printed Circuit Boards,简称PCBs)非金属粉末中热固性环氧树脂在热的无机酸中能完全分解成环氧树脂和玻璃纤维。选择了七种不同型号的废弃PCBs非金属粉末作为研究对象,研究了这些非金属粉末中金属残留物的含量以及玻璃纤维的含量。结果显示,在非金属粉末中含有一定量的金属残留物。在七种不同型号的废弃PCBs非金属粉末中,玻璃纤维的含量也不一样,在纸基线路板中玻璃纤维含量较小,甚至不含玻璃纤维。还研究了环氧树脂回收量与分解时间的关系,并分别用SEM和FTIR表征回收的玻璃纤维和环氧树脂。

  17. Computer simulation of thermal-hydraulic transient events in multi-circuits with multipumps

    International Nuclear Information System (INIS)

    PANTERA-2 (from Programa para Analise Termo-hidraulica de Reatores a Agua - Program for Thermal-hydraulic Analysis of Water Reactors, Version 2), whose fundamentals are described in this work, is intended to carry out rod bundle subchannel analysis in conjunction with multiloop simulation. It solves simultaneously the conservation equations of mass, axial and lateral momentum, and energy for subchannel geometry coupled with the balance equations that describe the fluid flows in any number of coolant loops connected to a pressure vessel containing the rod bundle. As far as subchannel analysis is concerned, the basic computational strategy of PANTERA-2 comes from COBRA codes, but an alternative implicit solution method oriented to the pressure field has been used to solve the finite difference approximations for the balance laws. The results provided by the subchannel model comprise the fluid density, enthalpy, flow rate, and pressure fields in the subchannels. The loop model predicts the individual loop flows, total flow through the pressure vessel, and pump rotational speeds as a function of time subsequent to the failure of any number of the coolant pumps. The flow transients in the loops may initiated by partial, total or sequential loss of electric power to the operating pumps. Transient events caused by either shaft break or rotor locking may also be simulated. The changes in rotational speed of the pumps as a function of rime are determined from a torque balance. Pump dynamic head and hydraulic torque are calculated as a function of rotational speed and volumetric flow from two polar homologous curves supplied to the code in the tabular form. In order to illustrate the analytical capability of PANTERA-2, three sample problems are presented and discussed. Comparisons between calculated and measured results indicate that the program reproduces with a good accuracy experimental data for subchannel exit temperatures and critical heat fluxes in 5x5 rod bundles. It

  18. A demonstration of the value of general purpose, on-board satellite computers

    Science.gov (United States)

    Jenkins, R. E.; Whisnant, J. M.

    1978-01-01

    Failure of the solar panels to erect and spin stabilize the TRANSIT Improvement Program (TIP) satellites is discussed, with emphasis on how the flight computer was reprogrammed to perform various control functions in order to achieve a partial mission success. These functions include: (1) power management to avoid troublesome spacecraft blackouts; (2) achieve enough spin stability to fire the OATS thruster; (3) raise the parking orbit to a workable altitude; (4) remove a high tumble rate which was the indirect result of the failure; and (5) deploy the gravity-gradient boom successfully on TIP-3.

  19. COMPASS, the COMmunity Petascale project for Accelerator Science and Simulation, a board computational accelerator physics initiative

    Energy Technology Data Exchange (ETDEWEB)

    Cary, J.R.; Spentzouris, P.; Amundson, J.; McInnes, L.; Borland, M.; Mustapha, B.; Ostroumov, P.; Wang, Y.; Fischer, W.; Fedotov, A.; Ben-Zvi, I.; Ryne, R.; Esarey, E.; Geddes, C.; Qiang, J.; Ng, E.; Li, S.; Ng, C.; Lee, R.; Merminga, L.; Wang, H.; Bruhwiler, D.L.; Dechow, D.; Mullowney, P.; Messmer, P.; Nieter, C.; Ovtchinnikov, S.; Paul, K.; Stoltz, P.; Wade-Stein, D.; Mori, W.B.; Decyk, V.; Huang, C.K.; Lu, W.; Tzoufras, M.; Tsung, F.; Zhou, M.; Werner, G.R.; Antonsen, T.; Katsouleas, T.; Morris, B.

    2007-07-16

    Accelerators are the largest and most costly scientific instruments of the Department of Energy, with uses across a broad range of science, including colliders for particle physics and nuclear science and light sources and neutron sources for materials studies. COMPASS, the Community Petascale Project for Accelerator Science and Simulation, is a broad, four-office (HEP, NP, BES, ASCR) effort to develop computational tools for the prediction and performance enhancement of accelerators. The tools being developed can be used to predict the dynamics of beams in the presence of optical elements and space charge forces, the calculation of electromagnetic modes and wake fields of cavities, the cooling induced by comoving beams, and the acceleration of beams by intense fields in plasmas generated by beams or lasers. In SciDAC-1, the computational tools had multiple successes in predicting the dynamics of beams and beam generation. In SciDAC-2 these tools will be petascale enabled to allow the inclusion of an unprecedented level of physics for detailed prediction.

  20. RS-232 Led Board

    CERN Document Server

    Tskhvaradze, Vladimir

    2007-01-01

    This article demonstrates how to develop a Microchip PIC16F84 based device that supports RS-232 interface with PC. Circuit (LED Board) design and software development will be discussed. PicBasic Pro Compiler from microEngineering Labs, Inc. is used for PIC programming. Development of LED Board Control Console using C/C++ is also briefly discussed. The project requires basic work experience with Microchip PICs, serial communication and programming.

  1. Research review on the ways of disposal of waste printed circuit boards%废弃印刷线路板处置技术的研究进展

    Institute of Scientific and Technical Information of China (English)

    王波; 洪丽

    2013-01-01

    The present paper intends to provide a general review of the latest advances on how to dispose the ever-increasing waste placed or printed circuit boards in modern IT and other branches of electrical and electronic industries. The plastics, metals and fiberglass built-in such waste printed circuit boards make it a valuable secondary resource for recycle. On the other hand, if not properly handled, the components, such as heavy metals and brominated flame retardants, are inevitable to result in toxic damages which are extremely harmful to human health and pernicious to the environment. However, so far as we know, there have not been idealistic methods to do such disposal. Mechanical methods, like disassembly, crush and separation, though introduced as the most convenient practices, are still recommended as pretreatment means. Some other few primary technologies for this purpose, such as metallurgical methods, supercritical water oxidation, biological method, incineration, pyrolysis and gasification have also had their own advantages and disadvantages. Among them, it has to be pointed out that the molten salt gasification of such waste circuits has much greater advantages in performance in preventing secondary pollution due to its absorptive power for the bromine and other heavy metals by molten salts. The use of such molten salt technology in treating coal, biomass, organic waste, to name a few, has drawn vast attention in recent years. The experimental and theoretical research results in these areas also provide strong support for its application in disposing such waste printed circuits to be discarded. Nevertheless, since there is no reliable technology for large scale disposal of waste printed circuit boards for the time being, and only molten salt gasification method has nice pollution-control behaviors, we do believe it is urgent to put more thoughts to improve on the gasification process in molten salt reactor and optimize the device and amplify its design for

  2. Collecting data from a sensor network in a single-board computer

    Science.gov (United States)

    Casciati, F.; Casciati, S.; Chen, Z.-C.; Faravelli, L.; Vece, M.

    2015-07-01

    The EU-FP7 project SPARTACUS, currently in progress, sees the international cooperation of several partners toward the design and implementation of a satellite based asset tracking for supporting emergency management in crisis operations. Due to the emergency environment, one has to rely on a low power consumption wireless communication. Therefore, the communication hardware and software must be designed to match requirements which can only be foreseen at the level of more or less likely scenarios. The latter aspect suggests a deep use of a simulator (instead of a real network of sensors) to cover extreme situations. The former power consumption remark suggests the use of a minimal computer (Raspberry Pi) as data collector. In this paper, the results of a broad simulation campaign are reported in order to investigate the accuracy of the received data and the global power consumption for each of the considered scenarios.

  3. Easy-to-Implement Project Integrates Basic Electronics and Computer Programming

    Science.gov (United States)

    Johnson, Richard; Shackelford, Ray

    2008-01-01

    The activities described in this article give students excellent experience with both computer programming and basic electronics. During the activities, students will work in small groups, using a BASIC Stamp development board to fabricate digital circuits and PBASIC to write program code that will control the circuits they have built. The…

  4. Readout boards for silicon detectors

    International Nuclear Information System (INIS)

    With ever increasing demands for greater miniaturization and the use of sophisticated circuitry in nuclear and particle physics experiments, the need for improved design of Printed Circuit Boards (PCBs) is becoming more important day by day. Interconnecting traces, parasitic components, grounding schemes and decoupling makes the design of the layout of PCBs as demanding as the design of the complex electrical circuit. An astute design of the readout boards is important in the success of the overall performance of the final system

  5. The LMT circuit and SPICE

    DEFF Research Database (Denmark)

    Lindberg, Erik; Murali, K.; Tamacevicius, Arunas

    2006-01-01

    The state equations of the LMT circuit are modeled as a dedicated analogue computer circuit and solved by means of PSpice. The nonlinear part of the system is studied. Problems with the PSpice program are presented....

  6. Performance analysis of electrical circuits /PANE/

    Science.gov (United States)

    Johnson, K. L.; Steinberg, L. L.

    1968-01-01

    Automated statistical and worst case computer program has been designed to perform dc and ac steady circuit analyses. The program determines the worst case circuit performance by solving circuit equations.

  7. Visualization of circuit card electromagnetic fields

    Science.gov (United States)

    Zwillinger, Daniel

    1995-01-01

    Circuit boards are used in nearly every electrical appliance. Most board failures cause differing currents in the circuit board traces and components. This causes the circuit board to radiate a differing electromagnetic field. Imaging this radiated field, which is equivalent to measuring the field, could be used for error detection. Using estimates of the fields radiated by a low power digital circuit board, properties of known materials, and available equipment, we determined how well the following technologies could be used to visualize circuit board electromagnetic fields (prioritized by promise): electrooptical techniques, magnetooptical techniques, piezoelectric techniques, thermal techniques, and electrodynamic force technique. We have determined that sensors using the electrooptical effect (Pockels effect) appear to be sufficiently sensitive for use in a circuit board imaging system. Sensors utilizing the magnetooptical effect may also be adequate for this purpose, when using research materials. These sensors appear to be capable of achieving direct broadband measurements. We also reviewed existing electromagnetic field sensors. Only one of the sensors (recently patented) was specifically designed for circuit board measurements.

  8. Circuits and filters handbook

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    A bestseller in its first edition, The Circuits and Filters Handbook has been thoroughly updated to provide the most current, most comprehensive information available in both the classical and emerging fields of circuits and filters, both analog and digital. This edition contains 29 new chapters, with significant additions in the areas of computer-aided design, circuit simulation, VLSI circuits, design automation, and active and digital filters. It will undoubtedly take its place as the engineer's first choice in looking for solutions to problems encountered in the design, analysis, and behavi

  9. MOS integrated circuit design

    CERN Document Server

    Wolfendale, E

    2013-01-01

    MOS Integral Circuit Design aims to help in the design of integrated circuits, especially large-scale ones, using MOS Technology through teaching of techniques, practical applications, and examples. The book covers topics such as design equation and process parameters; MOS static and dynamic circuits; logic design techniques, system partitioning, and layout techniques. Also featured are computer aids such as logic simulation and mask layout, as well as examples on simple MOS design. The text is recommended for electrical engineers who would like to know how to use MOS for integral circuit desi

  10. Applications of Computer Graphics in Engineering

    Science.gov (United States)

    1975-01-01

    Various applications of interactive computer graphics to the following areas of science and engineering were described: design and analysis of structures, configuration geometry, animation, flutter analysis, design and manufacturing, aircraft design and integration, wind tunnel data analysis, architecture and construction, flight simulation, hydrodynamics, curve and surface fitting, gas turbine engine design, analysis, and manufacturing, packaging of printed circuit boards, spacecraft design.

  11. Difference-Equation/Flow-Graph Circuit Analysis

    Science.gov (United States)

    Mcvey, I. M.

    1988-01-01

    Numerical technique enables rapid, approximate analyses of electronic circuits containing linear and nonlinear elements. Practiced in variety of computer languages on large and small computers; for circuits simple enough, programmable hand calculators used. Although some combinations of circuit elements make numerical solutions diverge, enables quick identification of divergence and correction of circuit models to make solutions converge.

  12. Ablation and carbon deposition induced by UV laser irradiation of polyimide: Application to the metallization of VIAs in high density printed circuit boards

    International Nuclear Information System (INIS)

    Polyimides are known to exhibit large ablation rates upon irradiation with excimer laser due to their high absorbance in the UV and low fluorescence yield. We have studied different regimes of laser ablation according to the fluence and studied the structures resulting from carbon products deposition. For fluences larger than the polyimide ablation threshold, but lower than the carbon one, the development of one structure is the dominant process, whereas large ablation rates lead to polyimide etching above the carbon ablation threshold. The deposition of a carbon layer on the walls of ablated slits has in particular been investigated using an original experimental technique. Optical microscopy and MEB have shown that this carbon layer covered the main height of the ablated holes whereas a threshold (bare polyimide) for carbon condensation was evidenced at the bottom of the ablated hole. Raman spectroscopy and conductivity measurements have shown that the carbon phase is mainly graphitic. A dependence of the carbon condensation threshold on the slit width has been evidenced and discussed in relation with the angle of ejection of ablation debris. A procedure has been developed to render the bare polyimide of the threshold region conductive. At last the conductive properties of the walls of the ablated holes have been exploited to perform an electrolytic metallization. Implications for the production of interconnection vertical interconnections (VIAs) in high density printed circuits are addressed

  13. 某电路板厂职业病危害控制效果评价%Evaluation of Control Effect on Occupational Hazards of a Circuit Board-making Factory

    Institute of Scientific and Technical Information of China (English)

    费小进; 童智敏; 杜成; 孟谦谦

    2011-01-01

    [ Objective] To understand the occupational hazards in a circuit board-making factory, cany out the evaluation of control effect on occupational hazards, and perfect the occupational protection measures. [Methods] On the basis of related information, the evaluation of control effect on occupational hazards was conducted by field investigation, checklist method and examination. [ Results]There were various occupational hazards in this factory, which mainly included soluble nickel compounds, hydrogen peroxide, cyanide, sulphuric acid, benzene, toluene, xylene, ammonia, sodium hydroxide, formaldehyde, hydrochloric acid, tin dioxide, other dust, noise, high temperature, power frequency electric field and X-rays. All results of field monitoring were in accordance with national occupational health standard. [ Conclusion ] The control effect on occupational hazards in a circuit board-making factory was basically qualified, and the field acceptance of occupational protective facilities can be carried out.%目的 为了解某电路板厂存在的职业危害,对该电路板厂进行职业病危害控制效果评价,完善职业病危害防护措施.方法 在收集相关资料的基础上,采用现场调查法、检查表分析法和检验检测法等方法,对其进行职业病危害控制效果评价.结果 该厂存在多种职业病危害因素,主要有可溶性镍化合物、过氧化氢、氰化物、硫酸、苯、甲苯、二甲苯、氨、氢氧化钠、甲醛、盐酸、二氧化锡、其他粉尘、噪声、高温、工频电场、X射线等;现场监测结果均符合国家职业卫生标准.结论 某电路板厂职业病危害控制效果基本合格,可以进行职业病危害防护设施的现场验收.

  14. 嗜酸菌对废旧印刷线路板金属铜的浸出研究%Research of Bio-leaching Cu from Printed-circuit Board by Acidophilus Strains

    Institute of Scientific and Technical Information of China (English)

    赵德龙; 谌书; 王中琪

    2012-01-01

    选用嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,简称T.f)、氧化硫硫杆菌(Thiobacillus thiooxidans,简称T.t)作为实验菌种研究其对线路板(Printed circuit board)粉金属铜的浸出;试验以单一菌种、混合菌种、无菌培养基及酸性蒸馏水进行浸出实验研究,通过对比不同条件下的浸出效果,得出单一氧化亚铁硫杆菌(T.f)的浸出效果最好,浸出率达到92.1%.通过对浸出过程中pH、ORP及Fe2+、Fe3+变化分析,发现Fe3+的氧化作用在铜的浸出过程中起主导作用,酸浸也有一定的贡献;对浸出后残余的PCB进行XRD及SEM观察分析发现,PCB组成成分中含有大量的酚烃、苯酚及邻、对位取代酚以及少量的长链烷烃及其脂肪烃,此类有机物在浸出过程中均与细菌或其代谢物发生了作用.%Two acidophilic strains, i.e, Acidithiobacillus ferrooxidans and Thiobacillus thiooxidans, were used to extract copper from the powder of printed circuit board (PCB). The experiment was conducted using different single strains and mixed bacteria, compared with others showing, the leaching behavior of, single Acidithiobacillus ferrooxidans was the best with leaching rate up to 92.1%. It was found that oxidation of Fe3+ was essential in bio-leaching of copper, and some organic compounds remained in PCB residues after the bio-leaching treatment, such as phenol hydrocarbons, phenol and osubstituted phenol and a small amount of long-chain alkanes and aliphatic hydrocarbons, with which the bacteria and their metabolites had reacted during the bio-leaching process.

  15. 电路板故障诊断的多总线自动测试技术研究%Research on multi-bus auto-test technology of circuit board fault diagnosis

    Institute of Scientific and Technical Information of China (English)

    邱云萍; 王琳; 王学伟; 程志华

    2012-01-01

    为满足现代越来越复杂的电子装备的测试需求,结合测试仪器接口多元化的发展,提出了将VXI、GPIB、1394集成于一体的多总线自动化测试系统。该测试系统采用具有高传输速率的VXI与1394总线,提高了电路板功能测试与故障诊断的效率。系统的通用性避免了测试系统重复性建设而造成的资金浪费,降低了测试成本。并以简单的继电器开关控制电路为例,使用支持向量机分类器对系统测试所得的样本进行故障诊断,诊断的准确率达到了99.73%。%To meet the increasingly complex modern electronic equipment test requirements,diversified with the development of the test instrument interface,put forward a multi-bus auto-test system which integrated VXI、GPIB、1394 in one.The test system used VXI and 1394 these high transmission rate buses,improved the circuit board functional test and fault diagnosis efficiency.Commonality of the system avoided the waste of money caused by the repetitive construction of a test system,reduced the cost of test.And take a simple relay switch control circuit for example,using SVM classifier to classify faults,it can make the accuracy rate of fault diagnosis achieve to 99.73%.

  16. Design and Implementation of an On-Board Fuel Computer Based on the STM32 Microprocessor%基于STM32的机载燃油计算机设计与实现

    Institute of Scientific and Technical Information of China (English)

    茹常剑; 景博; 吴桂胜

    2012-01-01

    Aimed at the defects of the fuel measurement system of our country's aircrafts in service, which are lower measurement accuracy, prominent maintenance problems and high failure rate, and the needs of the development of new aircraft, the embedded design idea is used to build a fuel computer based on the STM32 microprocessor. It can realize comprehensive management of the fuel system. First, the total design project of the fuel computer is put forward, which adopts key processing board plus peripheral circuitry. Second, we focus on illustrating the hardware design of a core processing board based on the STM32 microprocessor and the peripheral circuit including the signal conversion board based on CPLD and the control signal output board of electric relay. The application programs of automatic liquid level control, CPLD serial communication and 429 bus data receiving and sending are compiled. Finally, the fuel computer is tested and the results show that the fuel computer design is feasible. The achievement of the fuel computer has very important realistic significance to enhance fuel measurement accuracy and system maintenance and support.%针对我国现役战机电容式燃油测量系统测量精度低、维护保障问题突出、故障率较高的缺点以及对新型战机发展的需要,采用嵌入式设计理念构建基于STM32微处理器的燃油计算机,实现对燃油系统的综合管理.首先提出了核心处理板十外围电路的燃油计算机的总体设计方案,然后重点阐述了基于STM32微处理器的核心处理板和基于CPLD的信号转换板、继电器控制信号输出板的外围电路的硬件设计,编写了自动液面控制、CPLD串口通信和429总线数据收发的应用程序;最后给出了系统的实物图并对其进行了测试.测试结果表明,燃油计算机设计是可行的,该燃油计算机的构建将对提高燃油测量精度和系统维护保障性具有十分重要的现实意义.

  17. A COTS-based single board radiation-hardened computer for space applications; Monocarte ordinateur durcie aux radiations utilisant des COTS et destinee aux applications spatiales

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, S.; Hillman, R.; Layton, P.; Krawzsenek, D. [Space Electronics Inc., San Diego, CA (United States)

    1999-07-01

    There is great community interest in the ability to use COTS (Commercial-Off-The-Shelf) technology in radiation environments. Space Electronics, Inc. has developed a high performance COTS-based radiation hardened computer. COTS approaches were selected for both hardware and software. Through parts testing, selection and packaging, all requirements have been met without parts or process development. Reliability, total ionizing dose and single event performance are attractive. The characteristics, performance and radiation resistance of the single board computer will be presented. (authors)

  18. Bio-inspired feedback-circuit implementation of discrete, free energy optimizing, winner-take-all computations.

    Science.gov (United States)

    Genewein, Tim; Braun, Daniel A

    2016-06-01

    Bayesian inference and bounded rational decision-making require the accumulation of evidence or utility, respectively, to transform a prior belief or strategy into a posterior probability distribution over hypotheses or actions. Crucially, this process cannot be simply realized by independent integrators, since the different hypotheses and actions also compete with each other. In continuous time, this competitive integration process can be described by a special case of the replicator equation. Here we investigate simple analog electric circuits that implement the underlying differential equation under the constraint that we only permit a limited set of building blocks that we regard as biologically interpretable, such as capacitors, resistors, voltage-dependent conductances and voltage- or current-controlled current and voltage sources. The appeal of these circuits is that they intrinsically perform normalization without requiring an explicit divisive normalization. However, even in idealized simulations, we find that these circuits are very sensitive to internal noise as they accumulate error over time. We discuss in how far neural circuits could implement these operations that might provide a generic competitive principle underlying both perception and action. PMID:27023096

  19. 浅析某型号LED电子显示屏的印制板电磁兼容性改进%An Analysis of How to Improve the Electromagnetic Compatibility of the Printed Circuit Board of a Type of LED Electronic Display Screen

    Institute of Scientific and Technical Information of China (English)

    田文娟

    2012-01-01

    LED电子显示屏有着特殊构造方式,它不可避免地会向空间辐射电磁波。文章通过对LED电子显示屏电路印制板进行分析,分别从走线原则、接地以及分割几点改进印制板的电磁兼容性,对LED电子显示屏进行电磁辐射实际的测量,分别将改进前和改进后的测量结果进行分析。%The special construction of LED electronic display screen inevitably leads to electromagnetic radiation. This paper points out that the electromagnetic compatibility of the printed circuit board can be improved from three perspectives: the circuit layout principles, the earthed circuit, and the circuit partitioning. These suggestions are made on the basis of an analysis of the printed circuit board of LED electronic display screen, and an analysis of the results of the pre- and post-test of the electromagnetic radiation of LED electronic display screen before and after the improvement.

  20. Microelectrolysis / plate setter / biological contact oxidation process for treatment of printed circuit board wastewater%EGSB-CASS-生物滤池工艺处理天然橡胶加工废水

    Institute of Scientific and Technical Information of China (English)

    姚颋; 江丹丹; 李杰

    2012-01-01

    根据某天然橡胶加工企业生产废水的水质特点,采用EGSB-CASS-生物滤池工艺处理天然橡胶加工废水。工程运行结果表明,该工艺对CODCr、氨氮、SS平均去除率分别达到97%,94%,90%,出水水质符合GB8978-1996《污水综合排放标准》一级标准。%The wastewater from a plant of printed circuit board were collected and treated separately according to the wastewater quality. The integrated wastewater was treated by microelectrolysis/plate setter/biological contact oxidation process. The operation results showed that the effluent quality reached the first class of "Integrated Wastewater Discharge Standard" (GB8978-1996). This research obtained a feasible approach for PCB wastewater treatment.

  1. Microelectrolysis/plate setter/biological contact oxidation process for treatment of printed circuit board wastewater%微电解/斜板沉淀/生物接触氧化处理印刷电路板废水

    Institute of Scientific and Technical Information of China (English)

    姚颋; 王宏; 李杰

    2011-01-01

    根据某印刷电路板企业生产废水的水质特点,对废水进行分类收集处理后,采用微电解/斜板沉淀/生物接触氧化工艺处理综合废水。工程运行结果表明,该工艺处理效果稳定,出水水质符合《污水综合排放标准》(GB8978-1996)的一级排放标准。%The wastewater from a plant of printed circuit board were collected and treated separately according tothe wastewater quality. The integrated wastewater was treated by microelectrolysis/plate setter/biological contact oxidation process. The operation results showed that the effluent quality reached the first class of "Integrated Wastewater Discharge Standard" (GB8978-1996).This research obtained a feasible approach for PCB wastewater treatment.

  2. "Electronic Circuit Board Design"Course Practical Ability Training Based on School-enterprise Cooperation%基于校企合作的“电子线路板设计”课程实践能力培养

    Institute of Scientific and Technical Information of China (English)

    彭远芳; 黄晓峰

    2014-01-01

    “电子线路板设计”课程具有很强的实践性、实用性,针对课程教学过程注重软件EDA学习而忽视PCB板设计的可靠性、可制造性与可测试性等诸多问题,提出通过校企合作提升课程教学实践能力的若干建议,努力为学生提供体验完整工作过程的学习机会,增强学生适应企业实际工作环境和解决综合问题的能力,培养学生的实践能力、自律能力和协作精神。%"Electronic circuit board design"course has a strong practical, practicality, for the teaching learning process focused on the neglect of EDA software PCB design reliability, manufacturability and testability, and many other issues raised by school-enterprise cooperation a number of recommendations to enhance the ability of teaching practice, and strive to provide a complete experience working process of learning opportunities for students to enhance students 'ability to adapt to their actual work envi-ronment and comprehensive problem solving, students' practical ability, self-discipline and teamwork.

  3. An innovative "ChemicalVia" process for the production of high density interconnect printed circuit boards The ATLAS muon chamber quality control with the X-ray tomograph at CERN

    CERN Document Server

    Da Silva, Vitor; Watts, David; Van der Bij, Erik; Banhidi, Z; Berbiers, Julien; Lampl, W; Marchesotti, M; Rangod, Stephane; Sbrissa, E; Schuh, S; Voss, Rüdiger; Zhuravlov, V

    2004-01-01

    The ChemicalVia process, patented by CERN, provides a new method of making microvias in high-density multilayer printed circuit boards of different types, such as sequential build-up (SBU), high density interconnected (HDI), or laminated multi-chip modules (MCM-L). The process uses chemical etching instead of laser, plasma or other etching techniques and can be implemented in a chain production line. This results in an overall reduced operation and maintenance cost and a much shorter hole production time as compared with other microvia processes. copy Emerald Group Publishing Limited. 4 Refs.4 An essential part of the Muon Spectrometer of the ATLAS experiment is based on the Monitored Drift Tube (MDT) technology. About 1200 muon drift chambers are being built at 13 institutes all over the world. The MDT chambers require an exceptional mechanical construction accuracy of better than 20 mu m. A dedicated X-ray tomograph has been developed at CERN since 1996 to control the mechanical quality of the chambers. The...

  4. Design of the Wind Tunnel Model Communication Controller Board. Degree awarded by Christopher Newport Univ. on Dec. 1998

    Science.gov (United States)

    Wilson, William C.

    1999-01-01

    The NASA Langley Research Center's Wind Tunnel Reinvestment project plans to shrink the existing data acquisition electronics to fit inside a wind tunnel model. Space limitations within a model necessitate a distributed system of Application Specific Integrated Circuits (ASICs) rather than a centralized system based on PC boards. This thesis will focus on the design of the prototype of the communication Controller board. A portion of the communication Controller board is to be used as the basis of an ASIC design. The communication Controller board will communicate between the internal model modules and the external data acquisition computer. This board is based around an Field Programmable Gate Array (FPGA), to allow for reconfigurability. In addition to the FPGA, this board contains buffer Random Access Memory (RAM), configuration memory (EEPROM), drivers for the communications ports, and passive components.

  5. Advanced circuit simulation using Multisim workbench

    CERN Document Server

    Báez-López, David; Cervantes-Villagómez, Ofelia Delfina

    2012-01-01

    Multisim is now the de facto standard for circuit simulation. It is a SPICE-based circuit simulator which combines analog, discrete-time, and mixed-mode circuits. In addition, it is the only simulator which incorporates microcontroller simulation in the same environment. It also includes a tool for printed circuit board design.Advanced Circuit Simulation Using Multisim Workbench is a companion book to Circuit Analysis Using Multisim, published by Morgan & Claypool in 2011. This new book covers advanced analyses and the creation of models and subcircuits. It also includes coverage of transmissi

  6. SU-C-304-04: A Compact Modular Computational Platform for Automated On-Board Imager Quality Assurance

    International Nuclear Information System (INIS)

    Purpose: Traditionally, the assessment of X-ray tube output and detector positioning accuracy of on-board imagers (OBI) has been performed manually and subjectively with rulers and dosimeters, and typically takes hours to complete. In this study, we have designed a compact modular computational platform to automatically analyze OBI images acquired with in-house designed phantoms as an efficient and robust surrogate. Methods: The platform was developed as an integrated and automated image analysis-based platform using MATLAB for easy modification and maintenance. Given a set of images acquired with the in-house designed phantoms, the X-ray output accuracy was examined via cross-validation of the uniqueness and integration minimization of important image quality assessment metrics, while machine geometric and positioning accuracy were validated by utilizing pattern-recognition based image analysis techniques. Results: The platform input was a set of images of an in-house designed phantom. The total processing time is about 1–2 minutes. Based on the data acquired from three Varian Truebeam machines over the course of 3 months, the designed test validation strategy achieved higher accuracy than traditional methods. The kVp output accuracy can be verified within +/−2 kVp, the exposure accuracy within 2%, and exposure linearity with a coefficient of variation (CV) of 0.1. Sub-millimeter position accuracy was achieved for the lateral and longitudinal positioning tests, while vertical positioning accuracy within +/−2 mm was achieved. Conclusion: This new platform delivers to the radiotherapy field an automated, efficient, and stable image analysis-based procedure, for the first time, acting as a surrogate for traditional tests for LINAC OBI systems. It has great potential to facilitate OBI quality assurance (QA) with the assistance of advanced image processing techniques. In addition, it provides flexible integration of additional tests for expediting other OBI

  7. SU-C-304-04: A Compact Modular Computational Platform for Automated On-Board Imager Quality Assurance

    Energy Technology Data Exchange (ETDEWEB)

    Dolly, S [Washington University School of Medicine, Saint Louis, MO (United States); University of Missouri, Columbia, MO (United States); Cai, B; Chen, H; Anastasio, M; Sun, B; Yaddanapudi, S; Noel, C; Goddu, S; Mutic, S; Li, H [Washington University School of Medicine, Saint Louis, MO (United States); Tan, J [UTSouthwestern Medical Center, Dallas, TX (United States)

    2015-06-15

    Purpose: Traditionally, the assessment of X-ray tube output and detector positioning accuracy of on-board imagers (OBI) has been performed manually and subjectively with rulers and dosimeters, and typically takes hours to complete. In this study, we have designed a compact modular computational platform to automatically analyze OBI images acquired with in-house designed phantoms as an efficient and robust surrogate. Methods: The platform was developed as an integrated and automated image analysis-based platform using MATLAB for easy modification and maintenance. Given a set of images acquired with the in-house designed phantoms, the X-ray output accuracy was examined via cross-validation of the uniqueness and integration minimization of important image quality assessment metrics, while machine geometric and positioning accuracy were validated by utilizing pattern-recognition based image analysis techniques. Results: The platform input was a set of images of an in-house designed phantom. The total processing time is about 1–2 minutes. Based on the data acquired from three Varian Truebeam machines over the course of 3 months, the designed test validation strategy achieved higher accuracy than traditional methods. The kVp output accuracy can be verified within +/−2 kVp, the exposure accuracy within 2%, and exposure linearity with a coefficient of variation (CV) of 0.1. Sub-millimeter position accuracy was achieved for the lateral and longitudinal positioning tests, while vertical positioning accuracy within +/−2 mm was achieved. Conclusion: This new platform delivers to the radiotherapy field an automated, efficient, and stable image analysis-based procedure, for the first time, acting as a surrogate for traditional tests for LINAC OBI systems. It has great potential to facilitate OBI quality assurance (QA) with the assistance of advanced image processing techniques. In addition, it provides flexible integration of additional tests for expediting other OBI

  8. 超低速直流电机电刷短路系数计算%Computation of brush short-circuit coefficients of DC machines for extremely low speed drives

    Institute of Scientific and Technical Information of China (English)

    张琪; 谢国栋; 黄苏融

    2006-01-01

    Short circuit due to the brushes over the commutator segments of DC machines causes reduction in the armature resistance and flux linkage, which is especially meaningful when the electric machine is running at zero or extremely low speed. In design computation of DC machines, usually the average values of the coefficients are used in consideration of the effects of the short circuit.However, the average values have complicated relationships with the parameters of electric machines, therefore, no usable mathematical model has been established yet for precise computation. In this paper, a relatively simple and generalized method for precise computation of the average values of the short-circuit coefficients is proposed. This method decouples some of the machine parameters and, therefore establishes a highly parameterized mathematical model and is convenient in formulation for computation. In addition, the computation data for one and two brush pairs, which are the most common cases, is provided.

  9. COMPUTING

    CERN Multimedia

    M. Kasemann

    Overview In autumn the main focus was to process and handle CRAFT data and to perform the Summer08 MC production. The operational aspects were well covered by regular Computing Shifts, experts on duty and Computing Run Coordination. At the Computing Resource Board (CRB) in October a model to account for service work at Tier 2s was approved. The computing resources for 2009 were reviewed for presentation at the C-RRB. The quarterly resource monitoring is continuing. Facilities/Infrastructure operations Operations during CRAFT data taking ran fine. This proved to be a very valuable experience for T0 workflows and operations. The transfers of custodial data to most T1s went smoothly. A first round of reprocessing started at the Tier-1 centers end of November; it will take about two weeks. The Computing Shifts procedure was tested full scale during this period and proved to be very efficient: 30 Computing Shifts Persons (CSP) and 10 Computing Resources Coordinators (CRC). The shift program for the shut down w...

  10. COMPUTING

    CERN Multimedia

    I. Fisk

    2010-01-01

    Introduction The first data taking period of November produced a first scientific paper, and this is a very satisfactory step for Computing. It also gave the invaluable opportunity to learn and debrief from this first, intense period, and make the necessary adaptations. The alarm procedures between different groups (DAQ, Physics, T0 processing, Alignment/calibration, T1 and T2 communications) have been reinforced. A major effort has also been invested into remodeling and optimizing operator tasks in all activities in Computing, in parallel with the recruitment of new Cat A operators. The teams are being completed and by mid year the new tasks will have been assigned. CRB (Computing Resource Board) The Board met twice since last CMS week. In December it reviewed the experience of the November data-taking period and could measure the positive improvements made for the site readiness. It also reviewed the policy under which Tier-2 are associated with Physics Groups. Such associations are decided twice per ye...

  11. Quantum Circuits with Mixed States

    OpenAIRE

    Aharonov, Dorit; Kitaev, Alexei; Nisan, Noam

    1998-01-01

    We define the model of quantum circuits with density matrices, where non-unitary gates are allowed. Measurements in the middle of the computation, noise and decoherence are implemented in a natural way in this model, which is shown to be equivalent in computational power to standard quantum circuits. The main result in this paper is a solution for the subroutine problem: The general function that a quantum circuit outputs is a probabilistic function, but using pure state language, such a func...

  12. 热应力-应变对线路板热物理改性影响研究%The effect of the thermal stress and strain on the heat physical modification of circuit board

    Institute of Scientific and Technical Information of China (English)

    易鸿

    2012-01-01

    文章根据废电路板材料热、力学性质差异,提出了加热改性预处理的技术方法.该方法基于物理改性和微观破坏,以提高破碎解离效率,实现金属与非金属的高度解离.通过加热改性处理,结合ANSYS有限元热应力模型,对改性作用进行分析;从环境风险管理的角度,评估热处理过程环境影响;从分离产物及其再生利用角度对加热改性处理后分离的非金属物料进行表征.研究结果可以为废电路板机械物理技术的提升和新工艺的开发提供理论基础,并为其他层压复合材料类废弃物资源化处理技术提供方法参考.%According to the difference of waste material thermal and mechanical properties circuit, a method of heating the pretreatment of modified technology is proposed. This method is based on physical modification and microscopic damage to increase crushing disintegrates efficiency and realizes disintegrating the metal and the non - metallic highly. Analyze the modification effect through the heating modification treatment com- bined with ANSYS finite element model; Assess the effect of the heat treatment process on environmental from the aspect of environmental risk management. Indicate characters of the modification of the heating sep- aration nonmetal materials by separation products and their recycling. The result provides the theoretical foundation for the waste circuit board mechanical and physical technology promotion and new process, and provides the reference method for other laminated composite material or wastes treatment technology.

  13. Synthetic in vitro circuits

    OpenAIRE

    Hockenberry, Adam J.; Jewett, Michael C.

    2012-01-01

    Inspired by advances in the ability to construct programmable circuits in living organisms, in vitro circuits are emerging as a viable platform for designing, understanding, and exploiting dynamic biochemical circuitry. In vitro systems allow researchers to directly access and manipulate biomolecular parts without the unwieldy complexity and intertwined dependencies that often exist in vivo. Experimental and computational foundations in DNA, DNA/RNA, and DNA/RNA/protein based circuitry have g...

  14. Key Technology of Disassembling Waste Printed Circuit Board Assembly for Components Reuse%面向元器件重用的废弃线路板拆解关键技术

    Institute of Scientific and Technical Information of China (English)

    向东; 张永凯; 李冬; 龙旦风; 牟鹏; 杨继平

    2013-01-01

    废弃线路板(Printed circuit board assembly,PCBA)上装配有大量高价值和有毒有害的元器件,一直是废旧电器电子产品(Waste electric and electronic equipment,WEEE)资源化关注的焦点.目前废弃线路板的资源化以材料循环利用为主,但研究发现线路板废弃时其上的元器件仍然具有良好的性能.为了实现废弃线路板上元器件的重用,在分析线路板组装与结构特点的基础上,针对解焊工艺,定量分析以贴片元器件(Surface mount devices,SMD)为主的线路板上的元器件的温度分布,确定了不同类型的线路板的加热工艺.针对线路板与元器件的连接方式,建立元器件的拆解加速度、分离位移和拆解能模型,提出面向元器件重用的废弃线路板拆解工艺,并分别针对以贴片元器件为主的线路板和以插装元器件为主的线路板开发相应的拆解设备.为了保证所拆解元器件的性能,初步探讨元器件可重用性的性能检测方法与流程.以线路板的拆解率和重用率为目标,优化面向元器件重用的线路板拆解工艺参数.%Waste printed circuit board assembly (PCBA),which has lots of high-value components and toxic substances,is a key unit in the disposal of waste electric and electronic equipment (WEEE).Up to now material recycling is still the main disposal method of waste PCBA.Studies show that the components still keep good condition when PCBA retired.In order to guarantee the reusability of the disassembled components,the components reuse-oriented disassembly technology is studied,in which the key technologies of heating and disassembly are discussed in detail.The key heating technology is researched for the different joint type of PCBA,the temperature distribution of surface mount devices (SMD) major PCBA is studied quantitatively.For getting the suitable disassembly mode of PCBA,the disassembly acceleration and separating displacement of components on PCB are defined and the

  15. Short-Circuit Withstand Current Rating for Low Voltage Switchgear : Short-Circuit Current Rating (SCCR)

    OpenAIRE

    Schütt, Matthias

    2016-01-01

    The subject of this thesis was to observe the short-circuit currents at electrical distribution boards. The purpose was to investigate different methods of protecting switchgears from dam-ages caused by short-circuit currents. Manufactures of switchgears need to indicate the rated short-circuit withstand current of their assembly. This thesis is presenting methods of defining the right value of the short-circuit withstand current. This thesis presents theoretical information about the cau...

  16. The Advanced On-board Processor (AOP)

    Science.gov (United States)

    Hartenstein, R. G.; Trevathan, C. E.; Stewart, W. N.

    1971-01-01

    The goal of the Advanced On-Board Processor (AOP) development program is to design, build, and flight qualify a highly reliable, moderately priced, digital computer for application on a variety of spacecraft. Included in this development program is the preparation of a complete support software package which consists of an assembler, simulator, loader, system diagnostic, operational executive, and many useful subroutines. The AOP hardware/software system is an extension of the On-Board Processor (OBP) which was developed for general purpose use on earth orbiting spacecraft with its initial application being on-board the fourth Orbiting Astronomical Observatory (OAO-C). Although the OBP possesses the significant features that are required for space application, however, when operating at 100% duty cycle the OBP is too power-consuming for use on many smaller spacecraft. Computer volume will be minimized by implementing the processor and input/output portions of the machine with large scale integrated circuits. Power consumption will be reduced through the use of plated wire and, in some cases, semiconductor memory elements.

  17. 废旧印刷电路板中电子元器件回收处理技术进展%Review on the Recycling Technologies of Electronic Components from Waste Printed Circuit Boards

    Institute of Scientific and Technical Information of China (English)

    孙春旭; 郭杰; 王建波; 许振明

    2016-01-01

    Electronic components are widely used in the electronic and electrical appliances.However,large quantities of electronic components are coming into discarding period due to the endless requirement for new products and market explosion for electronic and electrical products.The valuable materials and toxic materials of electronic components are analyzed.The new recycling processes for electronic components are reviewed,including the disas-sembling technologies (unsoldering methods and separation methods)and recycling technologies.On this basis,some new trends and suggestions on recovery of electronic components in waste printed circuit boards (WPCBs)are put for-ward.%电子元器件广泛应用于电子电器设备中,但由于产品更新换代和电子电器产业市场的膨胀,大量的电子元器件被丢弃。对电子元器件的资源性和危害性进行分析,综合评述了电子元器件回收利用的最新研究进展和成果,主要包括电子元器件的拆卸技术(解锡方法和分离方法)和回收技术。在此基础上,提出了废旧印刷电路板中电子元器件的无害化和资源化回收研究新动向及发展建议。

  18. Study on Advanced Treatment of Printed Circuit Board Wastewater By MBR Process%MBR工艺深度处理印刷电路板废水的研究

    Institute of Scientific and Technical Information of China (English)

    聂凯; 黄伊丕; 潘涌璋; 叶林顺

    2014-01-01

    分别采用陶瓷膜和超滤膜生物反应器对某印刷电路板(PCB)厂现有废水处理厂出水进行深度处理研究。结果表明:在进水COD 191.2〜270.4 mg/L,氨氮30〜50 mg/L,MLSS 6500 mg/L,DO 4〜8 mg/L,反应时间为5 h的条件下,两种膜生物反应器出水COD和氨氮的浓度分别低于99.2 mg/L和0.759 mg/L,达到《污水综合排放标准》(GB8978-1996)中的一级排放标准。%The ceramic and hollow fiber ultrafiltration membrane bioreactors were separately applied for advanced treatment of the printed circuit board (PCB) wastewater. The results show that ,when concentration of dissolved oxygen (DO) is 4.0~8.0 mg/L , hydrodynamic retention time (HRT) is 5 h, MLSS is 6500 mg/L , COD and ammonia nitrogen are 191.2~270.4 mg/L and 30.0~50.0 mg/L respectively, COD and ammonia nitrogen in the effluent from membrane bioreactors are less 99.2 mg/L and 0.759 mg/L respectively;The quality of treated wastewater can meet the first grade of Integrated Wastewater Discharge Standard GB8978-1996.

  19. Research Progress of Corona Electrostatic Separation Technology in Waste Printed Circuit Boards Recycling%高压静电分选技术在回收废旧电路板中的研究进展

    Institute of Scientific and Technical Information of China (English)

    余璐璐; 许振明

    2011-01-01

    高压静电分选是利用物质的导电特性、介电常数差异,使静电力、重力、离心力等有效地作用在所有粒子上而实现分选,具有高效、低耗、环境友好等显著优点,是废旧电路板无害化处理和资源化利用的先进技术之一.分析了高压静电分选机的工作原理,结合对电场及空间电荷分布的研究和颗粒荷电及动力学过程研究的新进展,总结了应用于废旧电路板回收的高压电选机设备及工艺流程,并提出了该技术在废旧电路板回收再利用方面的一些新动向.%Corona electrostatic separation is an advanced technology for waste printed circuit boards safe disposal and utilization, with high efficiency, low consumption, environmentally friendly and other significant advantages.As the different materials have different electrical properties and dielectric constants, materials in corona electrostatic separator are separated by different static electricity, gravity and centrifugal force. The working principle of electrostatic separation first are analyzed, combined with the new progress of electric field and space charge distribution, as well as the dynamics of charged particles, and the optimization parameters of equipment and process are summarized.Some new trends of this technology are discussed as well.

  20. Launching applications on compute and service processors running under different operating systems in scalable network of processor boards with routers

    Science.gov (United States)

    Tomkins, James L.; Camp, William J.

    2009-03-17

    A multiple processor computing apparatus includes a physical interconnect structure that is flexibly configurable to support selective segregation of classified and unclassified users. The physical interconnect structure also permits easy physical scalability of the computing apparatus. The computing apparatus can include an emulator which permits applications from the same job to be launched on processors that use different operating systems.

  1. Who is the male homosexual? A computer-mediated exploratory study of gay male Bulletin Board System (BBS) users in New York City.

    Science.gov (United States)

    Nieto, D S

    1996-01-01

    Using simple computer technology, 290 male homosexual Bulletin Board System (BBS) users in the greater New York City area participated in a study, the objective results of which are presented here as information of potential importance and/or interest to social workers, psychologists, and related mental health professionals. While, in general, members of the population studied tend to look like everyone else, some interesting differences with respect to (1) health-related concerns and behaviors, (2) educational attainment, and (3) socio-emotional characteristics (measured by computer administration and scoring of the Myers-Briggs Type Indicator) were identified and are presented and discussed. Further work relative to the latter is both urged and anticipated in the mental health professions' continuing efforts to operationalize their shared concerns about and values related to diversity. PMID:8738747

  2. Note: A disposable x-ray camera based on mass produced complementary metal-oxide-semiconductor sensors and single-board computers

    Science.gov (United States)

    Hoidn, Oliver R.; Seidler, Gerald T.

    2015-08-01

    We have integrated mass-produced commercial complementary metal-oxide-semiconductor (CMOS) image sensors and off-the-shelf single-board computers into an x-ray camera platform optimized for acquisition of x-ray spectra and radiographs at energies of 2-6 keV. The CMOS sensor and single-board computer are complemented by custom mounting and interface hardware that can be easily acquired from rapid prototyping services. For single-pixel detection events, i.e., events where the deposited energy from one photon is substantially localized in a single pixel, we establish ˜20% quantum efficiency at 2.6 keV with ˜190 eV resolution and a 100 kHz maximum detection rate. The detector platform's useful intrinsic energy resolution, 5-μm pixel size, ease of use, and obvious potential for parallelization make it a promising candidate for many applications at synchrotron facilities, in laser-heating plasma physics studies, and in laboratory-based x-ray spectrometry.

  3. Note: A disposable x-ray camera based on mass produced complementary metal-oxide-semiconductor sensors and single-board computers

    Energy Technology Data Exchange (ETDEWEB)

    Hoidn, Oliver R.; Seidler, Gerald T., E-mail: seidler@uw.edu [Physics Department, University of Washington, Seattle, Washington 98195 (United States)

    2015-08-15

    We have integrated mass-produced commercial complementary metal-oxide-semiconductor (CMOS) image sensors and off-the-shelf single-board computers into an x-ray camera platform optimized for acquisition of x-ray spectra and radiographs at energies of 2–6 keV. The CMOS sensor and single-board computer are complemented by custom mounting and interface hardware that can be easily acquired from rapid prototyping services. For single-pixel detection events, i.e., events where the deposited energy from one photon is substantially localized in a single pixel, we establish ∼20% quantum efficiency at 2.6 keV with ∼190 eV resolution and a 100 kHz maximum detection rate. The detector platform’s useful intrinsic energy resolution, 5-μm pixel size, ease of use, and obvious potential for parallelization make it a promising candidate for many applications at synchrotron facilities, in laser-heating plasma physics studies, and in laboratory-based x-ray spectrometry.

  4. Note: A disposable x-ray camera based on mass produced complementary metal-oxide-semiconductor sensors and single-board computers.

    Science.gov (United States)

    Hoidn, Oliver R; Seidler, Gerald T

    2015-08-01

    We have integrated mass-produced commercial complementary metal-oxide-semiconductor (CMOS) image sensors and off-the-shelf single-board computers into an x-ray camera platform optimized for acquisition of x-ray spectra and radiographs at energies of 2-6 keV. The CMOS sensor and single-board computer are complemented by custom mounting and interface hardware that can be easily acquired from rapid prototyping services. For single-pixel detection events, i.e., events where the deposited energy from one photon is substantially localized in a single pixel, we establish ∼20% quantum efficiency at 2.6 keV with ∼190 eV resolution and a 100 kHz maximum detection rate. The detector platform's useful intrinsic energy resolution, 5-μm pixel size, ease of use, and obvious potential for parallelization make it a promising candidate for many applications at synchrotron facilities, in laser-heating plasma physics studies, and in laboratory-based x-ray spectrometry. PMID:26329247

  5. Note: A disposable x-ray camera based on mass produced complementary metal-oxide-semiconductor sensors and single-board computers

    International Nuclear Information System (INIS)

    We have integrated mass-produced commercial complementary metal-oxide-semiconductor (CMOS) image sensors and off-the-shelf single-board computers into an x-ray camera platform optimized for acquisition of x-ray spectra and radiographs at energies of 2–6 keV. The CMOS sensor and single-board computer are complemented by custom mounting and interface hardware that can be easily acquired from rapid prototyping services. For single-pixel detection events, i.e., events where the deposited energy from one photon is substantially localized in a single pixel, we establish ∼20% quantum efficiency at 2.6 keV with ∼190 eV resolution and a 100 kHz maximum detection rate. The detector platform’s useful intrinsic energy resolution, 5-μm pixel size, ease of use, and obvious potential for parallelization make it a promising candidate for many applications at synchrotron facilities, in laser-heating plasma physics studies, and in laboratory-based x-ray spectrometry

  6. Board news

    NARCIS (Netherlands)

    NN,

    1997-01-01

    Composition of the Board of the Foundation Flora Malesiana. — The Board met during the Flora of Thailand Symposium in Phuket. The members Dr. P. Baas and Dr. K. Iwatsuki, whose terms had expired, were happy to continue on the Board. Dr. S.H. Sohmer withdrew and Dr. A. Hay agreed to take the vacant c

  7. Design and implementation of a hybrid circuit system for micro sensor signal processing

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhuping; Chen Jing; Liu Ruqing, E-mail: wangzhuping169@163.com [School of Information and Electronics, Beijing Institute of Technology, Beijing 100081 (China)

    2011-04-15

    This paper covers a micro sensor analog signal processing circuit system (MASPS) chip with low power and a digital signal processing circuit board implementation including hardware connection and software design. Attention has been paid to incorporate the MASPS chip into the digital circuit board. The ultimate aim is to form a hybrid circuit used for mixed-signal processing, which can be applied to a micro sensor flow monitoring system. (semiconductor integrated circuits)

  8. Vacuum pyrolysis characteristics of waste printed circuit boards epoxy resin and analysis of liquid products%废弃电路板环氧树脂真空热解及产物分析

    Institute of Scientific and Technical Information of China (English)

    丘克强; 吴倩; 湛志华

    2009-01-01

    在真空条件下,应用程序升温的管式炉反应器对废弃电路板中环氧树脂热解规律进行研究,考察不同的热解终温、升温速率、真空度(压力)及保温时间等各种因素对产物产率的影响.此外,利用傅里叶红外(FT-IR)和气质联用(GC/MS)技术对热解油产物进行表征分析.实验结果表明:温度对产物产率的影响最大,升温速率、真空度及保温时间对热解产物产率也有重要影响.选择适当的热解温度(400~550 ℃)、升温速率(15~20 ℃/min)、真空度(压力15 kPa)及保温时间(30 min)有利于提高热解液体产品的产率;热解油的主要成分是酚类物质,其总含量为84.08%,其中,含溴化合物含量为15.34%.%The effect of pyrolysis conditions on the products yield of epoxy resin in waste printed circuit boards was investigated using the vacuum pyrolysis oven heated by temperature controller. The effects of temperature, heating rate, pressure and reaction time on the yield of vacuum pyrolysis production were analyzed. In addition, the compositions of liquid products were analyzed by FT-IR and GC/MS. The experimental results show that temperature is the key factor in the vacuum pyrolysis process. At the same time, heating rate, pressure and rest time cannot be neglected. The optimisation conditions for the liquid yield from the vacuum pyrolysis process are as follows: temperature 400-550 ℃, heating rate 15-20 ℃/min, pressure 15 kPa, and reaction time 30 min. The main composition in the product yield is Phenolic organic compounds with the total of 84.08%, while considerable amount of brominated products is up to 15.34%, which lowers the value of liquid products.

  9. 废旧印刷线路板的热重分析及热解动力学模型%Thermogravimetric Analysis and Pyrolysis Kinetics Models of Waste Printed Circuit Board

    Institute of Scientific and Technical Information of China (English)

    赵跃; 薛勇; 黄强; 邓欣逸; 张义烽

    2011-01-01

    The pyrolysis characteristics of waste FR4 type printed circuit board (PCB) was studied by thermogravimetric (TG) analysis method. The TG and differential thermogravimetry (DTG) curves of the waste PCB at different heating rate and their changing rules were explored. The activation energy (E) of the pyrolysis reaction was solved exactly by Starink method. The mechanism function and pre-exponential factor (A) were obtained by Malek method. The research results show that; The TG and DTG curves of waste FR4 type PCB move to the high-temperature zone progressively with the increase of heating rate; The initial pyrolysis temperature, the temperature corresponding to the maximum weight loss rate and the terminated pyrolysis temperature also increase with it; The E and A of the waste PCB are 105.75 kJ/mol and 7. 89 x 108 min-1 respectively.%采用热重(TG)分析法研究了废旧FR4型印刷线路板(PCB)的热解特性,探讨了不同升温速率下废旧PCB的TG和微分热重(DTG)曲线及变化规律,利用Starink法精确求解热解反应活化能(E),利用Malek法判断得出废旧PCB的热解动力学机理函数和指前因子(A).研究结果表明:废旧FR4型PCB的TG和DTG曲线随着升温速率的增大逐步向高温区移动;起始热解温度、最大失重速率对应温度以及终止热解温度也随着升温速率的增大而升高;废旧FR4型PCB的E和A分别为105.75 kJ/mol和7.89×108 min-1.

  10. Interfacial microstructures and solder joint strengths of the Sn-8Zn-3Bi and Sn-9Zn-lAl Pb-free solder pastes on OSP finished printed circuit boards

    International Nuclear Information System (INIS)

    Two kinds of lead-free solders, Sn-8Zn-3Bi and Sn-9Zn-lAl, were used to mount passive components onto printed circuit boards via a re-flow soldering process. The samples were stored at 150 deg. C for 200, 400, 600, 800, and 1100 h. The microstructures of the samples after aged at 150 deg. C for various times were characterized using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and the analyzed of solder joint shear strengths. The joint strength between Sn-8Zn-3Bi and Cu pad was about 4.0 ± 0.3 kg, while the strength between Sn-9Zn-lAl and Cu pad had values of 2.6 ± 0.1 kg. Both kinds of solder joints exhibited reduced strengths with increasing aging times. After aging at 150 deg. C for 1100 h, the joints strengths of Sn-8Zn-3Bi and Sn-9Zn-lAl were 1.8 ± 0.3 and 1.7 ± 0.3 kg, respectively. Both the Sn-8Zn-3Bi and Sn-9Zn-lAl joints showed brittle fracture behaviors. A flat layer of Cu5Zn8 intermetallic compound (IMC) was formed between Sn-8Zn-3Bi solder and Cu pad after reflow. When the aging time was increased to 400 h, Zn-depletion and formation of Cu6Sn5 IMC were observed in the solders due to the interaction between the tin and zinc compounds. The interaction between Sn-9Zn-lAl solder and Cu pad had similar behavior, however, Cu6Sn5 IMC formed in Sn-9Zn-lAl solder when after aging at 150 deg. C for 600 h. As the aging time increased, both types of solders generated clear IMC spalling layers with large and continuous voids. Those voids substantially decreased the joint strength

  11. Interfacial microstructures and solder joint strengths of the Sn-8Zn-3Bi and Sn-9Zn-lAl Pb-free solder pastes on OSP finished printed circuit boards

    Energy Technology Data Exchange (ETDEWEB)

    Lin, C.-T. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China); Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, 195 Section 4, Chung-Hsing Road, Chutung, Hsinchu 31040, Taiwan (China); Hsi, C.-S. [Department of Materials Science and Engineering, National United University, 1 Lein-Da, Kung-Ching Li, Miaoli 36003, Taiwan (China); Wang, M.-C. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China)], E-mail: mcwang@kmu.edu.tw; Chang, T.-C.; Liang, M.-K. [Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, 195 Section 4, Chung-Hsing Road, Chutung, Hsinchu 31040, Taiwan (China)

    2008-07-14

    Two kinds of lead-free solders, Sn-8Zn-3Bi and Sn-9Zn-lAl, were used to mount passive components onto printed circuit boards via a re-flow soldering process. The samples were stored at 150 deg. C for 200, 400, 600, 800, and 1100 h. The microstructures of the samples after aged at 150 deg. C for various times were characterized using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and the analyzed of solder joint shear strengths. The joint strength between Sn-8Zn-3Bi and Cu pad was about 4.0 {+-} 0.3 kg, while the strength between Sn-9Zn-lAl and Cu pad had values of 2.6 {+-} 0.1 kg. Both kinds of solder joints exhibited reduced strengths with increasing aging times. After aging at 150 deg. C for 1100 h, the joints strengths of Sn-8Zn-3Bi and Sn-9Zn-lAl were 1.8 {+-} 0.3 and 1.7 {+-} 0.3 kg, respectively. Both the Sn-8Zn-3Bi and Sn-9Zn-lAl joints showed brittle fracture behaviors. A flat layer of Cu{sub 5}Zn{sub 8} intermetallic compound (IMC) was formed between Sn-8Zn-3Bi solder and Cu pad after reflow. When the aging time was increased to 400 h, Zn-depletion and formation of Cu{sub 6}Sn{sub 5} IMC were observed in the solders due to the interaction between the tin and zinc compounds. The interaction between Sn-9Zn-lAl solder and Cu pad had similar behavior, however, Cu{sub 6}Sn{sub 5} IMC formed in Sn-9Zn-lAl solder when after aging at 150 deg. C for 600 h. As the aging time increased, both types of solders generated clear IMC spalling layers with large and continuous voids. Those voids substantially decreased the joint strength.

  12. Effect of additives on product of vacuum pyrolysis of waste epoxy printed circuit boards%添加物对废弃环氧电路板真空热解产物的影响

    Institute of Scientific and Technical Information of China (English)

    湛志华; 丘克强

    2011-01-01

    Printed circuit boards (PCBs) without metals and electronic components were pyrolysed in a pipe furnace to separate and recover the organic. The elemental composition of PCBs was analyzed by elemental analyzer and SEM-EDS. PCBs were pyrolysed under control with temperature controller with a series of additives respectively, and the pyrolysis products were analyzed using FT-IR, GC-MS. The results show Fe2O3 and metal additives lead the pyrolysis oil yield reduce to 30.0%. Twenty products in pyrolysis oil can be identified and the main components in the pyrolysis oil are phenol and 4-isopropylphenol. Iron and metal oxides can reduce the bromine content of pyrolyisis oil effectively.%采用程序升温控制的电阻炉,在自制的裂解反应器中对废弃电路板环氧树脂进行在真空条件下的热解实验,并考察金属、金属氧化物和分子筛共12种添加物对废弃电路板环氧树脂真空热解产物产率的影响.利用元素分析仪和SEM-EDS对环氧树脂电路板组成进行分析,对不同添加物与废弃电路板环氧树脂共热裂解得到的裂解油进行FT-IR和GC-MS检测,对其主要组分进行结构鉴定和分析.研究结果表明:Fe2O3和金属添加物(Cu和Fe)使热解油产率降到最低(30.0%);从热解油中鉴定出20种物质,其中主要成分为苯酚和异丙基苯酚;金属铁及其氧化物能有效降低裂解油中的溴化物含量.

  13. A dishwasher for circuits

    CERN Multimedia

    Rosaria Marraffino

    2014-01-01

    You have always been told that electronic devices fear water. However, at the Surface Mount Devices (SMD) Workshop here at CERN all the electronic assemblies are cleaned with a machine that looks like a… dishwasher.   The circuit dishwasher. Credit: Clara Nellist.  If you think the image above shows a dishwasher, you wouldn’t be completely wrong. Apart from the fact that the whole pumping system and the case itself are made entirely from stainless steel and chemical resistant materials, and the fact that it washes electrical boards instead of dishes… it works exactly like a dishwasher. It’s a professional machine (mainly used in the pharmaceutical industry) designed to clean everything that can be washed with a water-based chemical soap. This type of treatment increases the lifetime of the electronic boards and therefore the LHC's reliability by preventing corrosion problems in the severe radiation and ozone environment of the LHC tunn...

  14. Brain circuits underlying visual stability across eye movements-converging evidence for a neuro-computational model of area LIP

    OpenAIRE

    Arnold Ziesche; Hamker, Fred H.

    2014-01-01

    The understanding of the subjective experience of a visually stable world despite the occurrence of an observer's eye movements has been the focus of extensive research for over 20 years. These studies have revealed fundamental mechanisms such as anticipatory receptive field (RF) shifts and the saccadic suppression of stimulus displacements, yet there currently exists no single explanatory framework for these observations. We show that a previously presented neuro-computational model of peri-...

  15. Electronic design with integrated circuits

    Science.gov (United States)

    Comer, D. J.

    The book is concerned with the application of integrated circuits and presents the material actually needed by the system designer to do an effective job. The operational amplifier (op amp) is discussed, taking into account the electronic amplifier, the basic op amp, the practical op amp, analog applications, and digital applications. Digital components are considered along with combinational logic, digital subsystems, the microprocessor, special circuits, communications, and integrated circuit building blocks. Attention is given to logic gates, logic families, multivibrators, the digital computer, digital methods, communicating with a computer, computer organization, register and timing circuits for data transfer, arithmetic circuits, memories, the microprocessor chip, the control unit, communicating with the microprocessor, examples of microprocessor architecture, programming a microprocessor, the voltage-controlled oscillator, the phase-locked loop, analog-to-digital conversion, amplitude modulation, frequency modulation, pulse and digital transmission, the semiconductor diode, the bipolar transistor, and the field-effect transistor.

  16. Model Order Reduction for Electronic Circuits:

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Shontz, Suzanne

    Electronic circuits are ubiquitous; they are used in numerous industries including: the semiconductor, communication, robotics, auto, and music industries (among many others). As products become more and more complicated, their electronic circuits also grow in size and complexity. This increased...... the need for circuit simulators to evaluate potential designs before fabrication, as integrated circuit prototypes are expensive to build, and troubleshooting is difficult. In this report, we focus on the simulation of printed circuit boards (PCB’s) and interconnects both of which are of great importance...... in the semiconductor industry. Circuit simulation proceeds by using Maxwell’s equations to create a mathematical model of the circuit. The boundary element method is then used to discretize the equations, and the variational form of the equations are then solved on the graph network....

  17. 77 FR 38880 - Privacy Act of 1974, as Amended; Computer Matching Program (SSA/Railroad Retirement Board (SSA...

    Science.gov (United States)

    2012-06-29

    ... RRB-20 systems of records. We will match RRB's data with our Medicare Database (MDB) File, system of... Post Entitlement System file daily. The number of records will differ each day, but consist of... computer matching program that we are currently conducting with RRB. DATES: We will file a report of...

  18. 75 FR 53005 - Privacy Act of 1974, as amended; Notice of Computer Matching Program (Railroad Retirement Board...

    Science.gov (United States)

    2010-08-30

    ..., Earnings Recording and Self-Employment Income System (MEF); 71 FR 1819 (January 11, 2006) 3. SSA/OSR 60..., Office of Management and Budget (OMB). ADDRESSES: Interested parties may comment on this publication by... program was published at 73 FR 31516-31517 (June 2, 2008). B. RRB Computer Matches Subject to the...

  19. Circuit Quantum Electrodynamics

    CERN Document Server

    Bishop, Lev S

    2010-01-01

    Circuit Quantum Electrodynamics (cQED), the study of the interaction between superconducting circuits behaving as artificial atoms and 1-dimensional transmission-line resonators, has shown much promise for quantum information processing tasks. For the purposes of quantum computing it is usual to approximate the artificial atoms as 2-level qubits, and much effort has been expended on attempts to isolate these qubits from the environment and to invent ever more sophisticated control and measurement schemes. Rather than focussing on these technological aspects of the field, this thesis investigates the opportunities for using these carefully engineered systems for answering questions of fundamental physics.

  20. Brain circuits underlying visual stability across eye movements - converging evidence for a neuro-computational model of area LIP

    Directory of Open Access Journals (Sweden)

    Arnold eZiesche

    2014-03-01

    Full Text Available The understanding of the subjective experience of a visually stable world despite the occurrence of an observer's eye movements has been the focus of extensive research for over 20 years. These studies have revealed fundamental mechanisms such as anticipatory receptive field shifts and the saccadic suppression of stimulus displacements, yet there currently exists no single explanatory framework for these observations. We show that a previously presented neuro-computational model of peri-saccadic mislocalization accounts for the phenomenon of predictive remapping and for the observation of saccadic suppression of displacement (SSD. This converging evidence allows us to identify the potential ingredients of perceptual stability that generalize beyond different data sets in a formal physiology-based model. In particular we propose that predictive remapping stabilizes the visual world across saccades by introducing a feedback loop and, as an emergent result, small displacements of stimuli are not noticed by the visual system. The model provides a link from neural dynamics, to neural mechanism and finally to behavior, and thus offers a testable comprehensive framework of visual stability.

  1. Analysis of circuits including magnetic cores (MTRAC)

    Science.gov (United States)

    Hanzen, G. R.; Nitzan, D.; Herndon, J. R.

    1972-01-01

    Development of automated circuit analysis computer program to provide transient analysis of circuits with magnetic cores is discussed. Allowance is made for complications caused by nonlinearity of switching core model and magnetic coupling among loop currents. Computer program is conducted on Univac 1108 computer using FORTRAN IV.

  2. Research Progress of Gold Bio-leaching Technology from Waste Printed Circuit Board%电子垃圾中金的生物浸取技术研究进展

    Institute of Scientific and Technical Information of China (English)

    梁昌金

    2015-01-01

    With the continuous development of science and technology, electronic equipments renew fast-er and faster. If these waste equipments can be used environmentally friendly, not only can they reduce the envi-ronmental pressure, but also can make up for the shortage of resources. Biological metallurgy is a rapid develop-ment of technology, which can overcome the problems of traditional pyrometallurgy and hydrometallurgy exist-ing in the metal recycling, and is a promising green metallurgical method. As a means of biological metallurgy, using cyanide-generating bacteria to leach gold from waste printed circuit board powder it has attracted a great attention in recent years. This paper introduces research progress of gold bio-leaching technology, especially the gold leaching technology of cyanide-generating bacteria, then analyses its mechanism, gold leaching pro-cess, influencing factors, and the limitation of gold bio-leaching technology. Finally it points out that the biolog-ical method combined with physical and chemical methods, complement each other, is the development trend of gold bioleaching.%随着经济的增长和科技的进步,电子垃圾成为全球增长最快的垃圾。如果能用环境友好型的方式对电子垃圾中的有用资源进行回收,不仅可以减少环境压力,而且还可以弥补资源的短缺。生物冶金是一种快速发展的技术,它可以克服传统的湿法冶金和火法冶金在金属回收中存在的问题,是一种很有前途的绿色环保的冶金方法。作为生物冶金的一种方式,利用产氰细菌从废弃印刷线路板粉末中提取金,近年来更受到人们的关注。文章对生物浸金技术,尤其是产氰生物的浸金技术作了综述,分析了其在浸金过程中的机理、过程、影响因素,以及生物浸金技术的限制,最后指出将生物法与物理、化学方法相结合,取长补短,是未来生物浸金的发展趋势。

  3. 废弃印刷线路板资源化与无害化处理研究进展%Progress in Study of Recycling and Innocuous Treatment of Waste Printed Circuit Boards

    Institute of Scientific and Technical Information of China (English)

    刘维桥; 尚通明; 雷卫宁; 周全法

    2011-01-01

    From the viewpoints of renewable resource and environment protection, the recycling of waste printed circuit boards (PCBs) draw wide concerns as the amounts of waste PCBs increase dramatically. However recycling technology for waste PCBs in China is still immature. Current primary means for reusing waste PCBs were introduced, including incineration, chemical treatment, pyrolysis and mechanical treatment methods, with analysis of their advantages and disadvantages. New technologies being developed in recycling waste PCBs were described, including supercritical fluid process, biological process and plasma process. Directions for development of the technologies in recycling waste PCBs in future were discussed as well. It was proposed that technical transformation of existing methods should be continually strengthened. Efforts of study on new teehnologies and methods for recycling waste PCBs should be increased. Studies on recovery of NMFs from waste PCBs which included green recycling of flame retardants and development of new renewable and biodegradable materials should be concerned.%从资源再生的利用与环境保护的观点来看,随着废弃印刷线路板的迅速增加,回收废弃印刷线路板得到了越来越广泛的关注.然而,目前对废弃印刷线路板回收的技术还不够成熟.文章介绍了目前回收废弃印刷线路板的主要方法,包括焚烧法、化学处理法、热解法和机械处理法等,分析了各种方法的优缺点以及技术改进情况.综述了当前正在研究开发的回收废弃印刷线路板的新技术方法,包括超临界流体法、生物处理法和等离子体熔炼法等,总结了其研究进展情况.最后对回收废弃印刷线路板未来技术发展的方向进行了展望,指出了应加大在如下三个方面的研究力度.一是加强对目前已经采用的方法进行技术革新;二是增加对新方法新技术的研究投入;三是重视对废弃印刷线路板中非金属部分

  4. Construction and field test of a programmable and self-cleaning auto-sampler controlled by a low-cost one-board computer

    Science.gov (United States)

    Stadler, Philipp; Farnleitner, Andreas H.; Zessner, Matthias

    2016-04-01

    This presentation describes in-depth how a low cost micro-computer was used for substantial improvement of established measuring systems due to the construction and implementation of a purposeful complementary device for on-site sample pretreatment. A fully automated on-site device was developed and field-tested, that enables water sampling with simultaneous filtration as well as effective cleaning procedure of the devicés components. The described auto-sampler is controlled by a low-cost one-board computer and designed for sample pre-treatment, with minimal sample alteration, to meet requirements of on-site measurement devices that cannot handle coarse suspended solids within the measurement procedure or -cycle. The automated sample pretreatment was tested for over one year for rapid and on-site enzymatic activity (beta-D-glucuronidase, GLUC) determination in sediment laden stream water. The formerly used proprietary sampling set-up was assumed to lead to a significant damping of the measurement signal due to its susceptibility to clogging, debris- and bio film accumulation. Results show that the installation of the developed apparatus considerably enhanced error-free running time of connected measurement devices and increased the measurement accuracy to an up-to-now unmatched quality.

  5. A Research on the Application of the Multi-stage Countercurrent Cleaning Process Principle during Circuit Board Production%电镀、线路板生产过程多级串联逆流清洗工艺的应用研究

    Institute of Scientific and Technical Information of China (English)

    余秋良

    2012-01-01

    文章通过对多级串联逆流清洗工艺原理,以及工艺中的清洗级数、清洗水量和清洗时间等影响因素的研究,结合某线路板企业清洁生产改造的应用进行实例分析,得到该工艺有利于电镀和线路板生产企业大幅度节水和节省成本的结论,并提出清洗级数、末级清洗槽浓度等有关参数控制的建议。%The paper mainly conducted a research on the multi-stage countercurrent cleaning process principle, as well as influencing factors of the process such as its cleaning stages, cleaning water quantity and cleaning time. Combined with a case study on the application of clean production reformation by a circuit board enterprise, the paper concluded that the process was in favor of water-saving and cost-saving for circuit board manufacturers. It also proposes suggestions on relevant parameters such as the cleaning series and the concentration of final stage cleaning.

  6. Separating OR, SUM, and XOR Circuits

    OpenAIRE

    Find, Magnus; Göös, Mika; Järvisalo, Matti; Kaski, Petteri; Koivisto, Mikko; Korhonen, Janne H.

    2013-01-01

    Given a boolean n by n matrix A we consider arithmetic circuits for computing the transformation x->Ax over different semirings. Namely, we study three circuit models: monotone OR-circuits, monotone SUM-circuits (addition of non-negative integers), and non-monotone XOR-circuits (addition modulo 2). Our focus is on \\emph{separating} these models in terms of their circuit complexities. We give three results towards this goal: (1) We prove a direct sum type theorem on the monotone complexity of ...

  7. An Approach to Simplify Reversible Logic Circuits

    Directory of Open Access Journals (Sweden)

    Pabitra Roy

    2012-09-01

    Full Text Available Energy loss is one of the major problems in traditional irreversible circuits. For every bit of information loss kTln2 joules of heat is lost. In order to reduce the energy loss the concept of reversible logic circuits are introduced. Here we have described an algorithm for simplifying the reversible logic circuit and hence reduction of circuit cost and energy. The algorithm considers sub_circuit with respect to their number of lines and contiguous gates. The resulting sub_circuits are re-synthesized with smaller equivalent implementation. The process continues until circuit cost reaches good enough for Application or until a given computation budget has been exhausted. The circuit is constructed by NOT, CNOT and Toffoli gates only. By applying the algorithm and using the equivalent implementation we will get significant reduction of circuit cost and hence energy.

  8. Circuit Training.

    Science.gov (United States)

    Nelson, Jane B.

    1998-01-01

    Describes a research-based activity for high school physics students in which they build an LC circuit and find its resonant frequency of oscillation using an oscilloscope. Includes a diagram of the apparatus and an explanation of the procedures. (DDR)

  9. Controllable circuit

    DEFF Research Database (Denmark)

    2010-01-01

    A switch-mode power circuit comprises a controllable element and a control unit. The controllable element is configured to control a current in response to a control signal supplied to the controllable element. The control unit is connected to the controllable element and provides the control...

  10. Design and implementation of a hybrid circuit system for micro sensor signal processing*

    Institute of Scientific and Technical Information of China (English)

    Wang Zhuping; Chen Jing; Liu Ruqing

    2011-01-01

    This paper covers a micro sensor analog signal processing circuit system (MASPS) chip with low power and a digital signal processing circuit board implementation including hardware connection and software design.Attention has been paid to incorporate the MASPS chip into the digital circuit board. The ultimate aim is to form a hybrid circuit used for mixed-signal processing, which can be applied to a micro sensor flow monitoring system.

  11. Bioleaching of gold, copper and nickel from waste cellular phone PCBs and computer goldfinger motherboards by two Aspergillus nigerstrains

    OpenAIRE

    Jorge Enrique Madrigal-Arias; Rosalba Argumedo-Delira; Alejandro Alarcón; Ma. Remedios Mendoza-López; Oscar García-Barradas; Jesús Samuel Cruz-Sánchez; Ronald Ferrera-Cerrato; Maribel Jiménez-Fernández

    2015-01-01

    In an effort to develop alternate techniques to recover metals from waste electrical and electronic equipment (WEEE), this research evaluated the bioleaching efficiency of gold (Au), copper (Cu) and nickel (Ni) by two strains of Aspergillus niger in the presence of gold-plated finger integrated circuits found in computer motherboards (GFICMs) and cellular phone printed circuit boards (PCBs). These three metals were analyzed for their commercial value and their diverse applications in the indu...

  12. New Service Status Board

    CERN Multimedia

    2013-01-01

    On Monday 14 October, the Service Status Board for GS and IT will change. The new Status Board will be integrated with the CERN Service Portal and with the CERN Service Catalogue.   As of today, the SSB will display “Service Incidents”, “Planned Interventions” and “Service Changes”. References valid from 14 October: CERN SSB at https://cern.ch/ssb Computing SSB (previously IT SSB) at https://cern.ch/itssb   Nicole Cremel, IT and GS Service Management Support

  13. Evolvable designs of experiments applications for circuits

    CERN Document Server

    Iordache, Octavian

    2009-01-01

    Adopting a groundbreaking approach, the highly regarded author shows how to design methods for planning increasingly complex experiments. He begins with a brief introduction to standard quality methods and the technology in standard electric circuits. The book then gives numerous examples of how to apply the proposed methodology in a series of real-life case studies. Although these case studies are taken from the printed circuit board industry, the methods are equally applicable to other fields of engineering.

  14. Enhancing board effectiveness.

    Science.gov (United States)

    Curran, Connie R; Totten, Mary K

    2010-01-01

    Like any other job, board work is associated with specific competencies. Competencies are the combination of knowledge, skills, personal characteristics, and behaviors needed to perform a job or task effectively. Boards are only as strong as their weakest member. Board education should focus on improving the knowledge and skills of the board and individual members and on overall board performance. Assessment of individual board member performance is designed to evaluate the trustee's knowledge of board roles and responsibilities and the expectations of board members. Board effectiveness is built through competency-based board member recruitment and selection; board member education and development; and evaluation of board, board member, and meeting performance. PMID:21291066

  15. Computer Programming for Hydropower Station Short Circuit Calculation Based on Symmetrical Component Method%基于对称分量法的水电站短路计算程序编制

    Institute of Scientific and Technical Information of China (English)

    关仲

    2012-01-01

    Based on linearization characteristics method and symmetrical component method,the Visual Basic is used for programming of hydropower station short circuit calculation.The program involves mainly two states: transient short circuit and steady short circuit,which can obtain the symmetrical components(positive,negative and zero-sequence) of voltage and current,distributed on each branch circuit under various short circuit types and also can express them in phasor form(complex number) to meet actual requirements of the relay protection and the electric secondary specialty.Meanwhile,a comment on short circuit algorithm and some local optimization are given for computer programming.%基于对称分量法和直线化特性法,应用Visual Basic编制了水电站短路计算程序。该程序主要包含超瞬变短路和稳态短路2个阶段的内容,可获得各种短路类型下每条支路的电流、电压对称分量(正序、负序和零序),将其表示为相量(复数),可满足继电保护和电气二次专业实际需要。同时,对短路计算算法进行了评述和局部优化,以适应计算机编程。

  16. EDA circuit simulation

    International Nuclear Information System (INIS)

    EDA technique is used for circuit simulation. The circuit simulation and the analysis are made for a gate circuit one-shot multivibrator. The result shows: EDA circuit simulation is very useful technique

  17. Analog and VLSI circuits

    CERN Document Server

    Chen, Wai-Kai

    2009-01-01

    Featuring hundreds of illustrations and references, this book provides the information on analog and VLSI circuits. It focuses on analog integrated circuits, presenting the knowledge on monolithic device models, analog circuit cells, high performance analog circuits, RF communication circuits, and PLL circuits.

  18. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    2011-2015 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 411 members,representing a team of worldwide experts in surgery research.They are from 47 countries,including Argentina(3),Australia(13),Austria(4),Belarus(1),Belgium(3),Brazil(10),Canada(10),China(41),Czech Republic(1),Denmark

  19. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    2011-2015 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 411 members, representing a team of worldwide experts in surgery research. They are from 47 countries, including Argentina (3), Australia (13), Austria (4), Belarus (1), Belgium (3), Brazil (10), Canada (10), China (41), Czech Republic (1), Denmark (1), Egypt (3), Estonia (1), Finland

  20. Evaluation of On-Board kV Cone Beam Computed Tomography–Based Dose Calculation With Deformable Image Registration Using Hounsfield Unit Modifications

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study was to estimate the accuracy of the dose calculation of On-Board Imager (Varian, Palo Alto, CA) cone beam computed tomography (CBCT) with deformable image registration (DIR), using the multilevel-threshold (MLT) algorithm and histogram matching (HM) algorithm in pelvic radiation therapy. Methods and Materials: One pelvis phantom and 10 patients with prostate cancer treated with intensity modulated radiation therapy were studied. To minimize the effect of organ deformation and different Hounsfield unit values between planning CT (PCT) and CBCT, we modified CBCT (mCBCT) with DIR by using the MLT (mCBCTMLT) and HM (mCBCTHM) algorithms. To evaluate the accuracy of the dose calculation, we compared dose differences in dosimetric parameters (mean dose [Dmean], minimum dose [Dmin], and maximum dose [Dmax]) for planning target volume, rectum, and bladder between PCT (reference) and CBCTs or mCBCTs. Furthermore, we investigated the effect of organ deformation compared with DIR and rigid registration (RR). We determined whether dose differences between PCT and mCBCTs were significantly lower than in CBCT by using Student t test. Results: For patients, the average dose differences in all dosimetric parameters of CBCT with DIR were smaller than those of CBCT with RR (eg, rectum; 0.54% for DIR vs 1.24% for RR). For the mCBCTs with DIR, the average dose differences in all dosimetric parameters were less than 1.0%. Conclusions: We evaluated the accuracy of the dose calculation in CBCT, mCBCTMLT, and mCBCTHM with DIR for 10 patients. The results showed that dose differences in Dmean, Dmin, and Dmax in mCBCTs were within 1%, which were significantly better than those in CBCT, especially for the rectum (P<.05). Our results indicate that the mCBCTMLT and mCBCTHM can be useful for improving the dose calculation for adaptive radiation therapy