WorldWideScience

Sample records for circuit boards assembled

  1. 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.

  2. 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.

  3. Improving intrinsic corrosion reliability of printed circuit board assembly

    DEFF Research Database (Denmark)

    Ambat, Rajan; Conseil, Helene

    2016-01-01

    Corrosion reliability is a serious issue today for electronic devices, components, and bare printed circuit boards (PCBs) due to factors such as miniaturization, globalized manufacturing practices, and global usage. Electronic components and devices are exposed to a wide variety of climatic...

  4. Prototype circuit boards assembled with non-lead bearing solders

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.; Rejent, J.A.

    1998-04-01

    The 91.84Sn-3.33Ag-4.83Bi and 96.5Sn-3.5Ag Pb-free solders were evaluated for surface mount circuit board interconnects. The 63Sn-37Pb solder provided the baseline data. All three solders exhibited suitable manufacturability per a defect analyses of circuit board test vehicles. Thermal cycling had no significant effect on the 91.84Sn-3.33Ag-4.83Bi solder joints. Some degradation in the form of grain boundary sliding was observed in 96.5Sn-3.5Ag and 63Sn-37Pb solder joints. The quality of the solder joint microstructures showed a slight degree of degradation under thermal shock exposure for all of the solders tested. Trends in the solder joint shear strengths could be traced to the presence of Pd in the solder, the source of which was the Pd/Ni finish on the circuit board conductor features. The higher, intrinsic strengths of the Pb-free solders encouraged the failure path to be located in proximity to the solder/substrate interface where Pd combined with Sn to form brittle PdSn{sub 4} particles, resulting in reduced shear strengths.

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

    Science.gov (United States)

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

    2016-11-01

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

  6. 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…

  7. Printed Circuit Board Assembly for Use in Space Missions

    Science.gov (United States)

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

    2017-01-01

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

  8. 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...... structure was identified by Fourier transform infrared spectroscopy, 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 set-up. Localized extraction of residue was carried...

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

    Energy Technology Data Exchange (ETDEWEB)

    Ray, U.; Artaki, I.; Finley, D.W.; Wenger, G.M. [Bell Labs., Princeton, NJ (United States). Lucent Technologies; Pan, T.; Blair, H.D.; Nicholson, J.M. [Ford Motor Co., Dearborn, MI (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

    1996-10-01

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

  10. Workload Balancing in Printed Circuit Board Assembly Shops = Baskili Devre Karti Dizgi Atölyelerinde Hat Dengeleme

    Directory of Open Access Journals (Sweden)

    Ekrem DUMAN

    2005-01-01

    Full Text Available In assembling printed circuit boards (PCB, the use of numerically or computer controlled electronic component placement machines has become quite popular in the last decades. However, serious operations research problems arise through their use such as, allocation of component types to machines, board production schedule, feeder configuration and placement sequencing. In this study, the problem of allocation of component types to machines is taken up where two non-identical machines are deployed serially on a line to complete the assembly process of PCBs. For the solution of this problem three heuristic algorithms are suggested and their performances are investigated on experimental data.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-09-01

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

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

    Science.gov (United States)

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

    2014-03-01

    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.

  13. 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

  14. Control over self-assembly of diblock copolymers on hexagonal and square templates for high area density circuit boards.

    Science.gov (United States)

    Feng, Jie; Cavicchi, Kevin A; Heinz, Hendrik

    2011-12-27

    Self-assembled diblock copolymer melts on patterned substrates can induce a smaller characteristic domain spacing compared to predefined lithographic patterns and enable the manufacture of circuit boards with a high area density of computing and storage units. Monte Carlo simulation using coarse-grain models of polystyrene-b-polydimethylsiloxane shows that the generation of high-density hexagonal and square patterns is controlled by the ratio N(D) of the surface area per post and the surface area per spherical domain of neat block copolymer. N(D) represents the preferred number of block copolymer domains per post. Selected integer numbers support the formation of ordered structures on hexagonal (1, 3, 4, 7, 9) and square (1, 2, 5, 7) templates. On square templates, only smaller numbers of block copolymer domains per post support the formation of ordered arrays with significant stabilization energies relative to hexagonal morphology. Deviation from suitable integer numbers N(D) increases the likelihood of transitional morphologies between square and hexagonal. Upon increasing the spacing of posts on the substrate, square arrays, nested square arrays, and disordered hexagonal morphologies with multiple coordination numbers were identified, accompanied by a decrease in stabilization energy. Control over the main design parameter N(D) may allow an up to 7-fold increase in density of spherical block copolymer domains per surface area in comparison to the density of square posts and provide access to a wide range of high-density nanostructures to pattern electronic devices.

  15. 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.

  16. 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

  17. 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...

  18. 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

  19. 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.

  20. 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...

  1. 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.

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

    Science.gov (United States)

    2010-07-01

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

  3. 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.

  4. A Composite Capacitor/Inductor Assembly for Resonant Circuits

    Science.gov (United States)

    Hull, J. P.; Scholfield, D. W.

    2001-06-01

    Resonant structures are of interest due to their ability to produce oscillatory voltages in circuits. Past resonant structures have typically been designed using a lumped element capacitor for energy storage and a separate inductor. A composite capacitor/inductor assembly has been developed which merges the capacitance utilized for energy storage into the inductor, creating a consolidated electrical component. Composite capacitor/inductor assemblies are of interest due to the ability of these devices to produce resonant responses with one half the number of parts required by more traditional resonant structures. This composite capacitor/inductor could be utilized in applications of frequency band suppression or frequency band pass for frequencies in excess of 100 MHz, or where a resonant circuit is required to reside in an area of minimum space - such as a printed circuit board or an integrated circuit. The device and the mathematical treatment to predict the device's performance are described.

  5. Optical system facilitates inspection of printed circuit boards

    Science.gov (United States)

    Cridlin, M.; Oconnor, J.

    1968-01-01

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

  6. 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.

  7. 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%.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Rework of multilayer printed wiring board assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Clement, D.W.

    1976-08-01

    Processes of reworking printed wiring assemblies (PWA) built with multilayer printed wiring boards (MLPWB) were investigated. Because of the MLPWBs added thickness and increased heat absorption potential, assemblies built with these boards are suspected of being more susceptible to damage during component removal than assemblies built with single-layer double-sided boards. There also have been questions raised about the effect that rework has on the internal connections of the MLPWBs. A review and limited evaluation of all known rework methods resulted in selecting ''solder wick'' and ''vacuum extraction'' as the two main rework methods for use in the evaluations. The Appendix defines and describes these rework techniques. Two different groups of units, intended to be representative of a wide range of proposed and presently used MLPWB-component configurations, were fabricated and then reworked by variations of these two techniques. Approximately 16,000 internal connections of MLPWBs were subjected to rework. No internal connections became open or degraded. In addition, 80 PTHs with internal connections were subjected to 10 cycles of rework to examine the effect of rework on MLPWB internal connections. Continuity of the internal connections was measured before and after all rework. Even though the rework did cause extensive external damage to the MLPWBs (blisters, measles, and land damage, for example), there was no indication of internal connection degradation. The information received thus far leads to the conclusion that internal connections of MLPWBs are not likely to be degraded as a result of assembly rework.

  13. 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

  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. Stripline/Microstrip Transition in Multilayer Circuit Board

    Science.gov (United States)

    Epp, Larry; Khan, Abdur

    2005-01-01

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

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

    OpenAIRE

    A. de Luca Pennacchia; L. G. de la Fraga; U. Martínez Hernández

    2009-01-01

    The progressive implementation of software functions in Integrated Circuits (ICs) has considerably increased the number of transistors and pin connections of ICs. For that reason, Printed Circuit Boards (PCBs) are fabricated with the Surface Mount Technology (SMT) nowadays and IC mounting on PCB is a crucial process that requires high precision. An Automatic Mechanical Montage (AMM) system is used to mount ICs on the sockets using a couple of reference points for every IC in order to find the...

  17. 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

  18. Semaphorin signaling in vertebrate neural circuit assembly

    Directory of Open Access Journals (Sweden)

    Yutaka eYoshida

    2012-06-01

    Full Text Available Neural circuit formation requires the coordination of many complex developmental processes. First, neurons project axons over long distances to find their final targets and then establish appropriate connectivity essential for the formation of neuronal circuitry. Growth cones, the leading edges of axons, navigate by interacting with a variety of attractive and repulsive axon guidance cues along their trajectories and at final target regions. In addition to guidance of axons, neuronal polarization, neuronal migration and dendrite development must be precisely regulated during development to establish proper neural circuitry. Semaphorins consist of a large protein family, which includes secreted and cell surface proteins, and they play important roles in many steps of neural circuit formation. The major semaphorin receptors are plexins and neuropilins, however other receptors and co-receptors also mediate signaling by semaphorins. Upon semaphorin binding to their receptors, downstream signaling molecules transduce this event within cells to mediate further events, including alteration of microtubule and actin cytoskeletal dynamics. Here, I review recent studies on semaphorin signaling in vertebrate neural circuit assembly, with the goal of highlighting how this diverse family of cues and receptors imparts exquisite specificity to neural complex connectivity.

  19. 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.

  20. Connector and electronic circuit assembly for improved wet insulation resistance

    Science.gov (United States)

    Reese, Jason A.; Teli, Samar R.; Keenihan, James R.; Langmaid, Joseph A.; Maak, Kevin D.; Mills, Michael E.; Plum, Timothy C.; Ramesh, Narayan

    2016-07-19

    The present invention is premised upon a connector and electronic circuit assembly (130) at least partially encased in a polymeric frame (200). The assembly including at least: a connector housing (230); at least one electrical connector (330); at least one electronic circuit component (430); and at least one barrier element (530).

  1. 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.

  2. 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.

  3. Sliding contacts on printed circuit boards and wear behavior

    OpenAIRE

    Le Solleu, J.-P.

    2010-01-01

    Abstract 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 indust...

  4. 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.

  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. 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.

  7. 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.

  8. 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.

  9. Protocadherin 17 regulates presynaptic assembly in topographic corticobasal Ganglia circuits.

    Science.gov (United States)

    Hoshina, Naosuke; Tanimura, Asami; Yamasaki, Miwako; Inoue, Takeshi; Fukabori, Ryoji; Kuroda, Teiko; Yokoyama, Kazumasa; Tezuka, Tohru; Sagara, Hiroshi; Hirano, Shinji; Kiyonari, Hiroshi; Takada, Masahiko; Kobayashi, Kazuto; Watanabe, Masahiko; Kano, Masanobu; Nakazawa, Takanobu; Yamamoto, Tadashi

    2013-06-05

    Highly topographic organization of neural circuits exists for the regulation of various brain functions in corticobasal ganglia circuits. Although neural circuit-specific refinement during synapse development is essential for the execution of particular neural functions, the molecular and cellular mechanisms for synapse refinement are largely unknown. Here, we show that protocadherin 17 (PCDH17), one of the nonclustered δ2-protocadherin family members, is enriched along corticobasal ganglia synapses in a zone-specific manner during synaptogenesis and regulates presynaptic assembly in these synapses. PCDH17 deficiency in mice causes facilitated presynaptic vesicle accumulation and enhanced synaptic transmission efficacy in corticobasal ganglia circuits. Furthermore, PCDH17(-/-) mice exhibit antidepressant-like phenotypes that are known to be regulated by corticobasal ganglia circuits. Our findings demonstrate a critical role for PCDH17 in the synaptic development of specific corticobasal ganglia circuits and suggest the involvement of PCDH17 in such circuits in depressive behaviors.

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

    Science.gov (United States)

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

    2011-12-01

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

  11. Fractal Electronic Circuits Assembled From Nanoclusters

    Science.gov (United States)

    Fairbanks, M. S.; McCarthy, D.; Taylor, R. P.; Brown, S. A.

    2009-07-01

    Many patterns in nature can be described using fractal geometry. The effect of this fractal character is an array of properties that can include high internal connectivity, high dispersivity, and enhanced surface area to volume ratios. These properties are often desirable in applications and, consequently, fractal geometry is increasingly employed in technologies ranging from antenna to storm barriers. In this paper, we explore the application of fractal geometry to electrical circuits, inspired by the pervasive fractal structure of neurons in the brain. We show that, under appropriate growth conditions, nanoclusters of Sb form into islands on atomically flat substrates via a process close to diffusion-limited aggregation (DLA), establishing fractal islands that will form the basis of our fractal circuits. We perform fractal analysis of the islands to determine the spatial scaling properties (characterized by the fractal dimension, D) of the proposed circuits and demonstrate how varying growth conditions can affect D. We discuss fabrication approaches for establishing electrical contact to the fractal islands. Finally, we present fractal circuit simulations, which show that the fractal character of the circuit translates into novel, non-linear conduction properties determined by the circuit's D value.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

    depths. At present, the highest-temperature commercially available circuit boards are based on polyimide materials, and those have maximum use temperatures of 200 to 250°C. In addition to thermal stability, downhole electronics must also be fabricated into high-aspect-ratio packages. For example, the multilayer assemblies produced at SNL were approximately 2.5 cm wide and 50 cm long. Because of this very high form factor, glass-fiber-reinforced polymers are much more desirable than multilayer ceramic modules (MCM). MCMs have many advantages for some applications, but are susceptible to damage induced by the mechanical and vibrational loads commonly experienced by data-logging tools. Thus, as EGS technology continues to advance, there is a strong need for multilayer electronics that can provide the necessary thermal performance while also being compatible with high-form-factor circuit designs. This project involved the design and development of high-temperature circuit materials, as well as the fabrication and testing of circuit components. The material development included the evaluation of various polymer/fiberglass composites, whereas the circuit components were tested using conventional microelectronic evaluation techniques. This effort targeted development of a new class of high-temperature multilayer circuit boards for use in downhole data-logging applications where temperatures are on the order of 300°C. This is consistent with DOE’s multiyear plan for advancing technologies for use in enhanced geothermal systems. Organic and inorganic polymer systems, both with glass reinforcements, were considered to provide the following performance at elevated temperatures: • Mechanical strength and durability • High dielectric strength and electrical resistivity • Thermal stability • Strong adhesion to copper to ensure the reliability of the multilayer assemblies • Processing characteristics that are consistent with state-of-the-art multilayer circuit board

  19. 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…

  20. 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.

  1. 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.

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

    Science.gov (United States)

    Park, Young Jun; Fray, Derek J

    2009-05-30

    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(NH(4))(2)Cl(6). 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.

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

    Science.gov (United States)

    Jadhav, U.; Hocheng, H.

    2015-09-01

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

  4. 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

  5. Recent developments and perspective of the spent waste printed circuit boards.

    Science.gov (United States)

    Xu, Yuquan; Liu, Junsheng

    2015-05-01

    The amount of spent electronic and electrical solid wastes (i.e. e-wastes) has increased to a new level with the rapid development of electronic and electrical industries. Management of e-wastes challenges the administrators and researchers. As a major component of the e-waste stream, pollution caused by the spent printed circuit boards has captured increasing attention. Various innovative methods have recently been developed to dispose and reuse these municipal spent printed circuit boards. In this mini-review article, the disposal approaches for spent printed circuit boards are highlighted. The present state and future perspective are also discussed. We hope that this mini-review can promote the extensive understanding and effective disposal of the spent printed circuit boards in the field of solid waste treatment and resources.

  6. 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...

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

    OpenAIRE

    Marcos Paulo Kohler Caldas; Viviane Tavares de Morae; Eduardo Junca; Jorge Alberto Soares Tenório; Denise Crocce Romano Espinosa

    2015-01-01

    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 ox...

  8. 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.

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

    Science.gov (United States)

    Kim, Joohan; Choi, Haewoon

    2012-11-01

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

  10. Self-Assembled DNA Templated Nano-wires and Circuits

    Science.gov (United States)

    Braun, Erez

    2000-03-01

    The realization that conventional microelectronics is approaching its miniaturization limits has motivated the search for an alternative route based on self-assembled nanometer-scale electronics. We have recently proposed a new approach based on the hybridization of biological and electronic materials (Braun E., Eichen Y., Sivan U. and Ben-Yoseph G., Nature 391, 775 (1998)). The concept relies on a two-step self-assembly process. The inherent molecular recognition capabilities of DNA molecules are first utilized to construct a network that serves as a template for the subsequent assembly of electronic materials into a circuit. The utilization of DNA and its associated enzymatic machinery enables: (a) self-assembly of complex substrates, (b) specific molecular addresses for the localization of electronic materials (e.g., gold colloids) by standard molecular biology techniques, (c) interdevice wiring and (d) bridging the microscopic structures to the macroscopic world. The self-assembly of nanometer scale electronics relies on two complementary developments. First, the ability to convert DNA molecules into thin conductive wires and second, the self-assembly of complex extended DNA templates. Our progress in these two directions will be presented. Regarding the first issue, a physical process resulting in condensation of gold colloids onto DNA molecules enables the assembly of thin gold wires (around 100-200 A wide) having, in principle, unlimited extensions. The second issue is developed in the context of recombinant DNA which allows the self-assembly of precise molecular junctions and networks. Specifically, we use RecA protein, which is the main protein responsible for genetic recombination in E. Coli bacteria, to construct DNA junctions at pre-designed addresses (sequences) on the molecules. The integration of these processes allows advancing nanometer-scale electronics. A realistic fabrication scheme for a room-temperature single-electron transistor

  11. Hybrid microcircuit board assembly with lead-free solders

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.; Hernandez, C.L.; Rejent, J.A.

    2000-01-11

    An assessment was made of the manufacturability of hybrid microcircuit test vehicles assembled using three Pb-free solder compositions 96.5Sn--3.5Ag (wt.%), 91.84Sn--3.33Ag--4.83Bi, and 86.85Sn--3.15Ag--5.0Bi--5.0Au. The test vehicle substrate was 96% alumina; the thick film conductor composition was 76Au--21Pt--3Pd. Excellent registration between the LCCC or chip capacitor packages and the thick film solder pads was observed. Reduced wetting of bare (Au-coated) LCCC castellations was eliminated by hot solder dipping the I/Os prior to assembly of the circuit card. The Pb-free solders were slightly more susceptible to void formation, but not to a degree that would significantly impact joint functionality. Microstructural damage, while noted in the Sn-Pb solder joints, was not observed in the Pb-free interconnects.

  12. 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.

  13. 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.

  14. Printed Circuit Boards with Integrated Heat Carrier Channels for Deep Geothermal Resources

    Science.gov (United States)

    Krühn, T.; Overmeyer, L.

    2012-04-01

    The exploration of deep geothermal resources is still very expensive. A large amount of these costs is caused by the drilling process. The high price results from a high failure risk, slow drilling progress and a large amount of manual work. To develop deep heat mining to a sizeable contribution to the European energy portfolio, the exploration process has to become a lot cheaper. One step to achieve lower costs is to monitor and automate the drilling process. Therefore, electronic components such as sensors and data processing units must be integrated into the Bottom Hole Assembly (BHA). The integration of electronics into the BHA faces the challenge of high ambient temperatures. The project "Packaging of Electronic Components for High Temperature Applications" within the "Geothermal Energy and High Performance-Drilling Collaborative Research Program (gebo)" develops a system of heat carrier channels integrated in printed circuit boards (PCB). These channels can be perfused with fluids such as water, oil or gas and provide high heat convection rates. Such PCBs will be able to withstand high ambient temperatures up to 250 °C. We have simulated, manufactured and are currently testing prototype boards with integrated heat carrier channels featuring a thickness of only 1.6 mm. As a simulation scenario, we chose a board measuring 25 mm x 100 mm, dimensions suitable for integration into a BHA. An ambient temperature of 250 °C was used. The simulation results presented in this contribution illustrate that cooling of the whole board as well as cooling of hotspots is possible. The cooling channel layout being the key for high convection rates was meticulously studied and optimized. Parameters such as necessary flow rate and fluid pressure were adjusted accordingly. Preliminary experiments validate the demonstrated and discussed simulation results. With the proposed cooling system, it is possible to integrate microelectronic components into the BHA for drilling

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

    Science.gov (United States)

    Saleem, Nasir

    2017-01-01

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

  16. 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...

  17. Integration of multimode waveguides and micromirror couplers in printed circuit boards using laser ablation

    Science.gov (United States)

    Van Steenberge, Geert; Geerinck, Peter; Van Put, Steven; Van Daele, Peter

    2004-09-01

    Integration of optical interconnections on a Printed Circuit Board (PCB) is very challenging, as it should remain compatible with existing PCB manufacturing technology based on laminated FR4-substrates and making use of solder-reflow and well-known placement and assembly techniques. In this paper we will describe different technologies being used for integration of such optical interconnections in PCB's. As we will demonstrate, the use of laser ablation, already used in PCB manufacturing for microvia's, is a suitable technique for the fabrication of multimode waveguides and micromirrors to provide optical coupling. Laser ablation is a very flexible technology that is particularly well suited for structuring of polymers because of their excellent UV-absorption properties and highly non-thermal ablation behavior. One of the most critical problems on the integration of optical interconnections in PCB's is coupling the light in and out of the optical plane. Because in our set-up the excimer laser beam can be tilted, the 45 degrees micromirrors can be easily fabricated using laser ablation. The focus is on ablation of waveguides using a frequency tripled Nd-YAG laser and on ablation of 45 degrees facets using a KrF excimer laser. It is shown that these structures can be defined in one single processing step, resulting in a very accurate alignment.

  18. 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.

  19. Reliability of CGA/LGA/HDI Package Board/Assembly (Final Report)

    Science.gov (United States)

    Ghaffaroam. Reza

    2014-01-01

    Package manufacturers are now offering commercial-off-the-shelf column grid array (COTS CGA) packaging technologies in high-reliability versions. Understanding the process and quality assurance (QA) indicators for reliability are important for low-risk insertion of these advanced electronics packages. The previous reports, released in January of 2012 and January of 2013, presented package test data, assembly information, and reliability evaluation by thermal cycling for CGA packages with 1752, 1517, 1509, and 1272 inputs/outputs (I/Os) and 1-mm pitch. It presented the thermal cycling (-55C either 100C or 125C) test results for up to 200 cycles. This report presents up to 500 thermal cycles with quality assurance and failure analysis evaluation represented by optical photomicrographs, 2D real time X-ray images, dye-and-pry photomicrographs, and optical/scanning electron Microscopy (SEM) cross-sectional images. The report also presents assembly challenge using reflowing by either vapor phase or rework station of CGA and land grid array (LGA) versions of three high I/O packages both ceramic and plastic configuration. A new test vehicle was designed having high density interconnect (HDI) printed circuit board (PCB) with microvia-in-pad to accommodate both LGA packages as well as a large number of fine pitch ball grid arrays (BGAs). The LGAs either were assembled onto HDI PCB as an LGA or were solder paste print and reflow first to form solder dome on pads before assembly. Both plastic BGAs with 1156 I/O and ceramic LGAs were assembled. It also presented the X-ray inspection results as well as failures due to 200 thermal cycles. Lessons learned on assembly of ceramic LGAs are also presented.

  20. Computer-aided interactive structural optimization of printed-circuit-board design

    Science.gov (United States)

    Duncan, L. B.; Holman, R. E.; Lagasse, B. K.; Sakamoto, L. W.; Sunada, W. H.

    Electronic equipment operating in severe vibration environments plays a critical role in military and aerospace hardware. A crucial element of most modularized electronic equipment is the printed circuit board (PCB). Structural failures of such boards are almost entirely the result of imposed mechanical vibration. It is desirable to incorporate structural guidelines and analysis techniques at an early stage in board development when deficiencies may easily be corrected. However, there are a number of problems connected with such an approach. A computer program has been developed to address the considered situation. The program is to reduce PCB structural analysis to a level readily understood by the average designer. Another objective of the program is to encourage use of structural analysis at an early stage of PCB design and development. Attention is given to board geometry, program organization, board response computation, and a sample problem.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

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

    Science.gov (United States)

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

    2013-02-01

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

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

    OpenAIRE

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

    2013-01-01

    The aim of this study was to investigate the feasibility of using nonmetallic printed circuit board (PCB) waste as filler in recycled HDPE (rHDPE) in production of rHDPE/PCB composites. Maleic anhydride modified linear low-density polyethylene (MAPE) was used as compatibilizer. In particular, the effects of nonmetallic PCB and MAPE on mechanical properties of the composites were assessed through tensile, flexural and impact testing. Scanning electron microscope (SEM) was used to study the dis...

  8. High Aspect Ratio Microstructures in Flexible Printed Circuit Boards : Process and Applications

    OpenAIRE

    Yousef, Hanna

    2008-01-01

    Flexible printed circuit boards (flex PCBs) are used in a wide range of electronic devices today due to their light weight, bendability, extensive wiring possibilities, and low-cost manufacturing techniques. The general trend in the flex PCB industry is further miniaturization alongside increasing functionality per device and reduced costs. To meet these demands, a new generation of low cost manufacturing technologies is being developed to enable structures with smaller lateral dimensions and...

  9. 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.

  10. EMC and the printed circuit board design theory and layout made simple

    CERN Document Server

    Montrose, Mark I

    1999-01-01

    "This reference text shows how and why RF energy is created within a printed circuit board, and the manner in which propagation occurs. With thorough explanations, this book enables engineers to grasp both the fundamentals of EMC theory and signal integrity, along with the mitigation process needed to prevent an EMC event while maintaining optimal functionality for low- and high-technology products. Mr. Montrose also shows the relationship between time and frequency domains, helping one meet mandatory compliance requirements."--Jacket.

  11. Investigation of moisture uptake into printed circuit board laminate and solder mask materials

    DEFF Research Database (Denmark)

    Conseil, Helene; Gudla, Visweswara Chakravarthy; Borgaonkar, Shruti

    2017-01-01

    Presence of moisture in a printed circuit board (PCB) laminate, typically made of glass fibres reinforced epoxy polymer, significantly influences the electrical functionality in various ways and causes problems during soldering process. This paper investigates the water uptake of laminates coated...... with different solder mask materials and exposed to saturated water vapour and liquid water. The solder masks are characterised for their microstructure and constituent phases using scanning electron microscopy and X-ray diffraction. The observations are correlated with themoisture absorption characteristic...

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

    Science.gov (United States)

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

    2000-05-01

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

  13. The influence of novel organic gold complex on photoresist layers of printed circuit boards

    Directory of Open Access Journals (Sweden)

    Silvana Dimitrijević

    2015-12-01

    Full Text Available The goal of this paper was to study the influence of organic gold complex based on mercaptotriazole on photoresist layers used in manufacturing of printed circuit boards (PCBs. Investigations were performed by immersion the previously prepared boards in electrolytes with different pH values (pH=2, 4, 7, 9 and 12 at gold concentration of 2.5 g/dm3 and in gold complexes with different gold concentrations (1.5; 2.0; 2.5; 3.0 and 3.5 g/dm3 at pH value of pH=9. Investigations showed that photoresist layers on boards are the most resistant at optimal operating conditions, pH=9 and concentration of gold of 2.5 g/dm3.

  14. 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.

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

    Science.gov (United States)

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

    2009-03-01

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

  16. Randomized BioBrick assembly: a novel DNA assembly method for randomizing and optimizing genetic circuits and metabolic pathways.

    Science.gov (United States)

    Sleight, Sean C; Sauro, Herbert M

    2013-09-20

    The optimization of genetic circuits and metabolic pathways often involves constructing various iterations of the same construct or using directed evolution to achieve the desired function. Alternatively, a method that randomizes individual parts in the same assembly reaction could be used for optimization by allowing for the ability to screen large numbers of individual clones expressing randomized circuits or pathways for optimal function. Here we describe a new assembly method to randomize genetic circuits and metabolic pathways from modular DNA fragments derived from PCR-amplified BioBricks. As a proof-of-principle for this method, we successfully assembled CMY (Cyan-Magenta-Yellow) three-gene circuits using Gibson Assembly that express CFP, RFP, and YFP with independently randomized promoters, ribosome binding sites, transcriptional terminators, and all parts randomized simultaneously. Sequencing results from 24 CMY circuits with various parts randomized show that 20/24 circuits are distinct and expression varies over a 200-fold range above background levels. We then adapted this method to randomize the same parts with enzyme coding sequences from the lycopene biosynthesis pathway instead of fluorescent proteins, designed to independently express each enzyme in the pathway from a different promoter. Lycopene production is improved using this randomization method by about 30% relative to the highest polycistronic-expressing pathway. These results demonstrate the potential of generating nearly 20,000 unique circuit or pathway combinations when three parts are permutated at each position in a three-gene circuit or pathway, and the methodology can likely be adapted to other circuits and pathways to maximize products of interest.

  17. 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.

  18. 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.

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

    Science.gov (United States)

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

    2010-05-01

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

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

    Science.gov (United States)

    Sheng, Peter P; Etsell, Thomas H

    2007-08-01

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

  1. 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.

  2. Homogenization on Multi-Materials’ Elements: Application to Printed Circuit Boards and Warpage Analysis

    Directory of Open Access Journals (Sweden)

    Araújo Manuel

    2016-01-01

    Full Text Available Multi-material domains are often found in industrial applications. Modelling them can be computationally very expensive due to meshing requirements. The finite element properties comprising different materials are hardly accurate. In this work, a new homogenization method that simplifies the computation of the homogenized Young modulus, Poisson ratio and thermal expansion coefficient is proposed, and applied to composite-like material on a printed circuit board. The results show a good properties correspondence between the homogenized domain and the real geometry simulation.

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

    Science.gov (United States)

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

    2008-04-01

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

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

    Science.gov (United States)

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

    2017-02-01

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

  5. 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.

  6. 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.

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

    Science.gov (United States)

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

    2017-02-01

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

  8. 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.

  9. 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.

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

    Science.gov (United States)

    Zhang, Zhiyuan; Zhang, Fu-Shen

    2014-08-30

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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Simulation and Analysis of Dynamic Characteristics of3D Assembly Circuit Module with Finite Element Method

    Institute of Scientific and Technical Information of China (English)

    黄春跃; 周德俭; 黄红艳

    2004-01-01

    Based on the modal analysis theory and by using the dynamics finite element analysis model of a three-dimensional assembly circuit module, dynamic characteristics of circuit module have been studied, including both natural characteristics analysis and dynamic responses analysis. Using a subspace method, modal analysis is first carried out. The first 6 orders of natural frequencies and vibration modes are obtained. Influence of the number of the Z-shaped metal slices on dynamic characteristics of the entire structure is also studied.Harmonic response analysis is then conducted. The steady-state response when the circuit module is subjected to harmonic excitation is determined. A curve of the response values against frequencies is obtained. As a result, the optimal number of Z-shaped metal slices can be determined, and it can be assured that the three-dimensional assembly circuit module has good performance in terms of the dynamic characteristics.

  16. Assembly of Nanoscale Organic Single-Crystal Cross-Wire Circuits

    DEFF Research Database (Denmark)

    Bjørnholm, Thomas

    2009-01-01

    Organic single-crystal transistors and circuits can be assembled by nanomechanical manipulation of nanowires of CuPc, F(16)CuPc, and SnO(2):Sb. The crossed bar devices have low operational voltage, high mobility and are stable in air. They can be combined into circuits, providing varied functions...... including inverters and NOR and NAND logic gates, opening new opportunities for organic nanoelectronics and highly sophisticated integrated logic devices....

  17. Flexible Circuits and Soft Actuators by Printing Assembly of Graphene.

    Science.gov (United States)

    Li, Wenbo; Li, Fengyu; Li, Huizeng; Su, Meng; Gao, Meng; Li, Yanan; Su, Dan; Zhang, Xingye; Song, Yanlin

    2016-05-18

    An effective way to improve the electrical conductivity of printed graphene patterns was demonstrated by realizing the assembly of giant graphene oxide sheets during the printing process. The synergetic effect of printing-induced orientation and evaporation-induced interfacial assembly facilitated the formation of laminar-structured patterns. The resulting patterns after chemical reduction showed excellent electrical conductivity in printed graphene electronics. Because of their high conductivity, mechanical flexibility, and advantage in pattern design, printed graphene electrodes were applied in electrical-driven soft actuators, which can realize controllable deformation with low driving voltage. Such achievements will be of great significance for the development of graphene-based flexible and printed electronics.

  18. 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.

  19. 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

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

    Science.gov (United States)

    Cox, Gary L.

    2004-01-01

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

  1. Synthesis of Arbitrary Quantum Circuits to Topological Assembly

    Science.gov (United States)

    Paler, Alexandru; Devitt, Simon J.; Fowler, Austin G.

    2016-08-01

    Given a quantum algorithm, it is highly nontrivial to devise an efficient sequence of physical gates implementing the algorithm on real hardware and incorporating topological quantum error correction. In this paper, we present a first step towards this goal, focusing on generating correct and simple arrangements of topological structures that correspond to a given quantum circuit and largely neglecting their efficiency. We detail the many challenges that will need to be tackled in the pursuit of efficiency. The software source code can be consulted at https://github.com/alexandrupaler/tqec.

  2. Early experience modifies the postnatal assembly of autonomic emotional motor circuits in rats.

    Science.gov (United States)

    Card, J Patrick; Levitt, Pat; Gluhovsky, Maxim; Rinaman, Linda

    2005-10-01

    Rat pups that are repeatedly handled and separated from their dam exhibit altered adult behavioral, endocrine, and autonomic responses to stress, but the extent to which early handling and/or maternal separation (H/S) alters the development of circuits that underlie these responses is unknown. The present study tested the hypothesis that early H/S alters the postnatal assembly of synapses within preautonomic emotional motor circuits. Circuit development was traced by synapse-dependent retrograde transneuronal transport of pseudorabies virus (PRV) from the stomach wall. Control and H/S rats were analyzed between postnatal day 6 (P6) and P10, a period of rapid synaptic assembly among preautonomic circuit components. Pups in H/S groups were removed from their dam daily for either 15 min or 3 h beginning on P1, and were injected with virus on P8 and perfused on P10. Quantitative analyses of primary and transsynaptic PRV immunolabeling confirmed an age-dependent assembly of hypothalamic, limbic, and cortical inputs to autonomic nuclei. Circuit assembly was significantly altered in H/S pups, in which fewer neurons in the central amygdala, the bed nucleus of the stria terminalis, and visceral cortices were infected compared with age-matched controls. In contrast, H/S did not alter the assembly of paraventricular hypothalamic inputs to gastric autonomic neurons. H/S-related reductions in limbic and cortical transneuronal infection were similar in pups exposed daily to 15 min or 3 h maternal separation. These findings support the view that environmental events during early postnatal life can influence the formation of neural circuits that provide limbic and cortical control over autonomic emotional motor output.

  3. Rapid construction of insulated genetic circuits via synthetic sequence-guided isothermal assembly

    Energy Technology Data Exchange (ETDEWEB)

    Torella, JP; Boehm, CR; Lienert, F; Chen, JH; Way, JC; Silver, PA

    2013-12-28

    In vitro recombination methods have enabled one-step construction of large DNA sequences from multiple parts. Although synthetic biological circuits can in principle be assembled in the same fashion, they typically contain repeated sequence elements such as standard promoters and terminators that interfere with homologous recombination. Here we use a computational approach to design synthetic, biologically inactive unique nucleotide sequences (UNSes) that facilitate accurate ordered assembly. Importantly, our designed UNSes make it possible to assemble parts with repeated terminator and insulator sequences, and thereby create insulated functional genetic circuits in bacteria and mammalian cells. Using UNS-guided assembly to construct repeating promoter-gene-terminator parts, we systematically varied gene expression to optimize production of a deoxychromoviridans biosynthetic pathway in Escherichia coli. We then used this system to construct complex eukaryotic AND-logic gates for genomic integration into embryonic stem cells. Construction was performed by using a standardized series of UNS-bearing BioBrick-compatible vectors, which enable modular assembly and facilitate reuse of individual parts. UNS-guided isothermal assembly is broadly applicable to the construction and optimization of genetic circuits and particularly those requiring tight insulation, such as complex biosynthetic pathways, sensors, counters and logic gates.

  4. COLORFUL-Circuit: a platform for rapid multigene assembly, delivery and expression in plants

    Directory of Open Access Journals (Sweden)

    Hassan eGhareeb

    2016-03-01

    Full Text Available Advancing basic and applied plant research requires the continuous innovative development of the available technology toolbox. Essential components of this toolbox are methods that simplify the assembly, delivery and expression of multiple transgenes of interest. To allow simultaneous and directional multigene assembly on the same plant transformation vector, several strategies based on overlapping sequences or restriction enzymes have recently been developed. However, the assembly of homologous and repetitive DNA sequences can be inefficient and the frequent occurrence of target sequences recognized by commonly used restriction enzymes can be a limiting factor. Here, we noted that recognition sites for the restriction enzyme SfiI are rarely occurring in plant genomes. This fact was exploited to establish a multigene assembly system called COLORFUL-Circuit. To this end, we developed a set of binary vectors which provide a flexible and cost efficient cloning platform. The gene expression cassettes in our system are flanked with unique SfiI sites, which allow simultaneous multi-gene cassette assembly in a hosting binary vector. We used COLORFUL-Circuit to transiently and stably express up to four fluorescent organelle markers in addition to a selectable marker and analyzed the impact of assembly design on coexpression efficiency. Finally, we demonstrate the utility of our optimized COLORFUL-Circuit system in an exemplary case study, in which we monitored simultaneously the subcellular behavior of multiple organelles in a biotrophic plant-microbe interaction by Confocal Laser Scanning Microscopy.

  5. 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.

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

    Science.gov (United States)

    Chu, K; Rutt, B K

    1994-06-01

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

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

    Science.gov (United States)

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

    2017-01-01

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

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

    Science.gov (United States)

    Gao, Yujie; Li, Xingang; Ding, Hui

    2015-08-01

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

  9. Thiourea leaching gold and silver from the printed circuit boards of waste mobile phones.

    Science.gov (United States)

    Jing-ying, Li; Xiu-li, Xu; Wen-quan, Liu

    2012-06-01

    The present communication deals with the leaching of gold and silver from the printed circuit boards (PCBs) of waste mobile phones using an effective and less hazardous system, i.e., a thiourea leaching process as an alternative to the conventional and toxic cyanide leaching of gold. The influence of particle size, thiourea and Fe(3+) concentrations and temperature on the leaching of gold and silver from waste mobile phones was investigated. Gold extraction was found to be enhanced in a PCBs particle size of 100 mesh with the solutions containing 24 g/L thiourea and Fe(3+) concentration of 0.6% under the room temperature. In this case, about 90% of gold and 50% of silver were leached by the reaction of 2h. The obtained data will be useful for the development of processes for the recycling of gold and silver from the PCBs of waste mobile phones.

  10. 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.

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

    Science.gov (United States)

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

    2017-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Shen-yann; Huang, Hann S.; Peters, R.W.; Tsai, S.Y. (Argonne National Lab., IL (USA)); Tsai, Wen-Tien; Shieh, Shih-Shien; Hsieh, Te-Yuan; Hwang, Li-Shyong (CTCI Corp., Taipei (Taiwan)); Liu, Solo; Peng, Chien-Tang (Printed Wire Corp., Ping Chen, Taoyuan (Taiwan)); Wu, Min H. (Waste Minimization Technology International, Inc., Pewaukee, WI (USA))

    1990-01-01

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

  13. 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.

  14. 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

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

    Science.gov (United States)

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

    2017-03-23

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

  16. Preparation and characterization of superconductor thin films for application in printed circuit boards

    Energy Technology Data Exchange (ETDEWEB)

    Souza, G.A.; Carvalho, C.L.; Torsoni, G.B.; Rodrigues, V.D.; Souza, E.J.; Zadorosny, R. [UNESP, Ilha Solteira, SP (Brazil). Fac. de Engenharia. Grupo de Desenvolvimento e Aplicacoes de Materiais (GDAM)

    2011-07-01

    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

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

    Science.gov (United States)

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

    2005-03-01

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

  18. 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.

  19. SOURCES OF COPPER IONS AND SELECTED METHODS OF THEIR REMOVAL FROM WASTEWATER FROM THE PRINTED CIRCUITS BOARD PRODUCTION

    Directory of Open Access Journals (Sweden)

    Maciej Thomas

    2014-10-01

    Full Text Available This paper presents the issues related to the presence and removal of copper compounds from industrial effluents with including wastewater from plants involved in the production of printed circuit boards. Characterized the toxicological properties of selected copper compounds, described the applicable technological processes, sources of copper ions in the effluents and selected methods for their removal.

  20. Newnes electronics assembly handbook

    CERN Document Server

    Brindley, Keith

    2013-01-01

    Newnes Electronics Assembly Handbook: Techniques, Standards and Quality Assurance focuses on the aspects of electronic assembling. The handbook first looks at the printed circuit board (PCB). Base materials, basic mechanical properties, cleaning of assemblies, design, and PCB manufacturing processes are then explained. The text also discusses surface mounted assemblies and packaging of electromechanical assemblies, as well as the soldering process. Requirements for the soldering process; solderability and protective coatings; cleaning of PCBs; and mass solder/component reflow soldering are des

  1. 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.

  2. Effect of Interfacial Reactions on the Reliability of Lead-Free Assemblies after Board Level Drop Tests

    Science.gov (United States)

    Xia, Yanghua; Lu, Chuanyan; Xie, Xiaoming

    2007-09-01

    The reliability of lead-free electronic assemblies after board level drop tests was investigated. Thin small outline package (TSOP) components with 42 FeNi alloy leads were reflow soldered on FR4 printed circuit boards (PCBs) with Sn3.0Ag0.5Cu (wt%) solder. The effects of different PCB finishes [organic solderability preservative (OSP) and electroless nickel immersion gold (ENIG)], multiple reflow (once and three times), and isothermal aging (500 h at 125°C after one time reflow) were studied. The ENIG finish showed better performance than its OSP counterparts. With the OSP finish, solder joints reflowed three times showed obvious improvement compared to those of the sample reflowed once, while aging led to apparent degradation. The results showed that intermetallic compound (IMC) types, IMC microstructure and solder microstructure compete with each other, all playing very important roles in the solder joint lifetime. The results also showed that it is important to specify adequate conditions for a given reliability assessment program, to allow meaningful comparison between results of different investigators.

  3. High-efficiency thin and compact concentrator photovoltaics using micro-solar cells with via-holes sandwiched between thin lens-array and circuit board

    Science.gov (United States)

    Itou, Akihiro; Asano, Tetsuya; Inoue, Daijiro; Arase, Hidekazu; Matsushita, Akio; Hayashi, Nobuhiko; Futakuchi, Ryutaro; Inoue, Kazuo; Yamamoto, Masaki; Fujii, Eiji; Nakagawa, Tohru; Anda, Yoshiharu; Ishida, Hidetoshi; Ueda, Tetsuzo; Fidaner, Onur; Wiemer, Michael; Ueda, Daisuke

    2014-01-01

    We have developed a compact concentrator photovoltaic (CPV) module that comprises micro-solar cells with an area of ≈0.6 × 0.6 mm2 sandwiched between a 20-mm-thick lens array and a 1-mm-thick circuit board with no air gap. To establish electrical connections between the circuit board and the micro-solar cells, we developed a micro-solar cell with positive and negative electrodes on the lower face of the cell. In this study, we demonstrated the photovoltaic performance of the micro-solar cell closely approaches that of the standard solar cell measuring ≈5 × 5 mm2 commonly used in conventional CPVs under concentrated illumination. Our study showed that the negative effect on PV performance of perimeter carrier recombination in the micro-solar cell was insignificant under concentrated illumination. Finally, we assembled our micro-solar cells into a CPV module and achieved the module energy conversion efficiency of 34.7% under outdoor solar illumination.

  4. 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.

  5. 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

  6. Testing to Investigate Stress-LifetimeCharacteristics of High Voltage Printed Circuit Boards

    Science.gov (United States)

    El Korashy, Oliver; Franke, Andreas; Gollor, Matthias

    2014-08-01

    Printed circuit boards (PCBs) are typically used in all electronic equipment, including those conditioning or controlling high voltage (HV) for space satellite applications. With the use of new subsystems that require higher voltages (generally several hundred volts up to tens of kV), stress-lifetime issues are becoming more complex. In order to allow compact design and cost efficient production of HV modules, there is an increasing demand to improve the design of PCBs with encapsulation or conformal coating at higher voltages.Within a PCB there are a number of electrical field interfaces each of which can have individual stress- lifetime characteristics, and the influence of environmental aging should also be considered, which means a large number of sample types should be tested to gain experimental evidence to define the margin for each interface. This paper demonstrates a method to test multiple samples at a fixed DC voltage stress until the event of a breakdown, and presents test results from 6 single-sided encapsulated PCB samples.

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

    Science.gov (United States)

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

    2013-01-01

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

  8. 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.

  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. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fogarasi, Szabolcs [“Babeş-Bolyai” University, Faculty of Chemistry and Chemical Engineering, Department of Chemical Engineering, 11 Arany Janos Street, Cluj-Napoca RO-400028 (Romania); Imre-Lucaci, Florica [“Babeş-Bolyai” University, Interdisciplinary Research Institute on Bio-Nano-Sciences, 42 Treboniu Laurian Street, Cluj-Napoca RO-400271 (Romania); Imre-Lucaci, Árpád, E-mail: aimre@chem.ubbcluj.ro [“Babeş-Bolyai” University, Faculty of Chemistry and Chemical Engineering, Department of Chemical Engineering, 11 Arany Janos Street, Cluj-Napoca RO-400028 (Romania); Ilea, Petru [“Babeş-Bolyai” University, Faculty of Chemistry and Chemical Engineering, Department of Chemical Engineering, 11 Arany Janos Street, Cluj-Napoca RO-400028 (Romania)

    2014-05-01

    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.

  12. 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.

  13. Enhancement of leaching copper by electro-oxidation from metal powders of waste printed circuit board.

    Science.gov (United States)

    Ping, Zhu; ZeYun, Fan; Jie, Lin; Qiang, Liu; Guangren, Qian; Ming, Zhou

    2009-07-30

    Oxidation leaching copper from metal powders of waste printed circuit boards (PCBs) was conducted at room temperature in sulfuric acid solution. The result showed that the copper in metal powders was oxidized by Cu(2+) to form CuCl(2)(-) in the presence of chloride ion without electrochemical oxidation. Then, CuCl(2)(-) was oxidized into CuSO(4) by oxygen derived from the air insufflated into leaching solution. The leaching rate of copper reached 100%. The whole reaction took 5.5h because it was limited by the low solubility of the air in water. In the electro-oxidation conditions, the chloride ion was electro-oxidized into ClO(-), which oxidized CuCl(2)(-) into CuSO(4) and ClO(-) was reduced into Cl(-) itself again at the same time. Since Cl(-) was recycled in the solution not only as a complexing agent but also as an oxidant, which made the reaction speed up to 3.5h to reach 100% leaching rate. Leaching solution was concentrated to crystallize CuSO(4).5H(2)O, and crystal liquor was reused to leach copper from metal powders.

  14. Microbial recovery of copper from printed circuit boards of waste computer by Acidithiobacillus ferrooxidans.

    Science.gov (United States)

    Choi, Moon-Sung; Cho, Kyung-Suk; Kim, Dong-Su; Kim, Dong-Jin

    2004-01-01

    The bioleaching of copper contained in the printed circuit boards (PCB) of waste computers by A. ferrooxidans was studied. The Fe oxidation rates by A. ferrooxidans in the 9K medium supplemented with the leachate of PCB (0.15-0.13 g L(-1) d(-1)) were similar to that in the 9K medium without the leachate (0.15 g L(-1) d(-1)). This finding suggests that the leachate of PCB did not seriously affect the bioleaching process by this bacterium. The amount of copper leached from PCB shreds increased with the addition of ferrous ion and reached up to 5190 mg L(-1) when the initial concentration of Fe2+ ion was 7 g L(-1). As the microbial leaching progressed, pale brown precipitate was observed to form in the solution. Based on the total amount of copper, both in solution and precipitate, the optimal addition of ferrous ion for the leaching of copper was around 7 g L(-1). When citric acid was not added, only about 37 wt% of the total leached copper remained dissolved; however, the amount of dissolved copper increased to greater than 80 wt% in the presence of citric acid. This fact indicates that the addition of a complexing agent (citric acid) to the bioleaching solution can raise the solubility of the leached metal ions.

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

    Science.gov (United States)

    Wang, Jianbo; Xu, Zhenming

    2015-01-20

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

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

    Science.gov (United States)

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

    2015-08-28

    For recovering precious metals from waste printed circuit boards (PCBs), a novel hybrid technology including physical and biological methods was developed. It consisted of crushing, corona-electrostatic separation, and bioleaching. Bioleaching process is the focus of this paper. A novel bioreactor for bioleaching was designed. Bioleaching was carried out using Pseudomonas chlororaphis. Bioleaching experiments using mixed particles of Au and Cu were performed and leachate contained 0.006 mg/L, 2823 mg/L Au(+) and Cu(2+) respectively. It showed when Cu existed, the concentrations of Au were extremely small. This provided the feasibility to separate Cu from Au. The method of orthogonal experimental design was employed in the simulation bioleaching experiments. Experimental results showed the optimized parameters for separating Cu from Au particles were pH 7.0, temperature 22.5 °C, and rotation speed 80 r/min. Based on the optimized parameters obtained, the bioreactor was operated for recovering mixed Au and Cu particles. 88.1 wt.% of Cu and 76.6 wt.% of Au were recovered. The paper contributed important information to recover precious metals from waste PCBs.

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

    Science.gov (United States)

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

    2009-10-15

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

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

    Science.gov (United States)

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

    2015-07-01

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

  19. Pressure leaching of metals from waste printed circuit boards using sulfuric acid

    Science.gov (United States)

    Jha, Manis K.; Lee, Jae-Chun; Kumari, Archana; Choubey, Pankaj K.; Kumar, Vinay; Jeong, Jinki

    2011-08-01

    Printed circuit boards (PCBs) are essential components of electronic equipments which contain various metallic values. This paper reports a hydrometallurgical recycling process for waste PCBs, which consists of the novel pretreatment consisting of organic swelling of PCBs followed by sulfuric acid leaching of metals from waste PCBs. To recycle the waste PCBs, experiments were carried out for the recovery of copper from the crushed and organic swelled materials of waste PCBs using sulfuric acid leaching in presence of hydrogen peroxide under atmospheric and pressure condition. The leaching of PCBs at 90°C, pulp density 100 g/L under atmospheric condition, using 6M sulfuric acid resulted in the dissolution of a minor amount of copper due to the presence of plastic coating on the surface of metallic layers. On the other hand, when the liberated metal sheets from organic swelled PCBs were treated with dilute sulfuric acid of concentration 2M along with hydrogen peroxide in an autoclave under oxygen atmosphere, the percentage recovery of copper was found to increase from 59.63% to 97.01% with an increase in hydrogen peroxide concentration from 5 to 15% (v/v) keeping constant pulp density 30 g/L.

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

    Science.gov (United States)

    Flandinet, L; Tedjar, F; Ghetta, V; Fouletier, J

    2012-04-30

    Recycling of waste electrical and electronic equipments (WEEE) has been taken into consideration in the literature due to the large quantity of concerned wastes and their hazardous contents. The situation is so critical that EU published European Directives imposing collection and recycling with a minimum of material recovery [1]. Moreover, WEEEs contain precious metals, making the recycling of these wastes economically interesting, but also some critical metals and their recycling leads to resource conservation. This paper reports on a new approach for recycling waste printed circuit boards (WPCBs). Molten salts and specifically molten KOH-NaOH eutectic is used to dissolve glasses, oxides and to destruct plastics present in wastes without oxidizing the most valuable metals. This method is efficient for recovering a copper-rich metallic fraction, which is, moreover, cleared of plastics and glasses. In addition, analyses of gaseous emission show that this method is environmentally friendly since most of the process gases, such as carbon monoxide and dioxide and halogens, are trapped in the highly basic molten salt. In other respects, under operation without oxygen, a large quantity of hydrogen is produced and might be used as fuel gas or as synthesis gas, leading to a favourable energy balance for this new process.

  1. 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.

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

    Science.gov (United States)

    Fogarasi, Szabolcs; Imre-Lucaci, Florica; Imre-Lucaci, Arpád; Ilea, Petru

    2014-05-30

    The present study aims to develop an eco-friendly chemical-electrochemical process for the simultaneous recovery of copper and separation of a gold rich residue from waste printed circuit boards (WPCBs). The process was carried out by employing two different types of reactors coupled in series: a leaching reactor with a perforated rotating drum, for the dissolution of base metals and a divided electrochemical reactor for the regeneration of the leaching solution with the parallel electrowinning of copper. The process performances were evaluated on the basis of the dissolution efficiency, current efficiency and specific energy consumptions. Finally a process scale up was realized taking into consideration the optimal values of the operating parameters. The laboratory scale leaching plant allowed the recovery of a high purity copper deposit (99.04wt.%) at a current efficiency of 63.84% and specific energy consumption of 1.75kWh/kg cooper. The gold concentration in the remained solid residue was 25 times higher than the gold concentration in the initial WPCB samples.

  3. Quantitative Leaching of a Spent Cell Phone Printed Circuit Board by Hydrochloric acid

    Directory of Open Access Journals (Sweden)

    Alafara A. Baba

    2014-07-01

    Full Text Available This paper presents a kinetic data on the hydrometallurgical recovery of some metal ions from a printed circuit board (PCB of a spent cell phone by hydrochloric acid leaching. The effects of acid concentration, temperature and particle diameter on the dissolution efficiency at various leaching time intervals were examined. The results of the leaching investigations showed that the powdered cell phone dissolution increases with increasing acid concentration, system temperature with decreasing particle diameter at 360 rpm. With 2M HCl solution, about 88.49% of the sample was dissolved within 120 minutes using 0.075-0.112 mm particle diameter at 800 C. The results of the study indicated that the dissolution reaction could be represented by a shrinking core model with surface chemical reaction. A value of 0.61, 60.67 kJ/mol and 12.9s-1 were calculated as reaction order, activation energy and frequency factor, respectively for the dissolution process.

  4. 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.

  5. 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.

  6. 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.

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

    Science.gov (United States)

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

    2014-02-01

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

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

    Science.gov (United States)

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

    2013-10-01

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

  9. Asphalt modified with nonmetals separated from pulverized waste printed circuit boards.

    Science.gov (United States)

    Guo, Jiuyong; Guo, Jie; Wang, Shifeng; Xu, Zhenming

    2009-01-15

    Nonmetals separated from pulverized waste printed circuit boards (PCBs) were reused as a new modifier to improve the performance of asphalt. The classical and rheological properties of unmodified asphalt and non-metal-modified asphalt (NMA) were determined. Specifically, the influence of nonmetals content and particle size on these properties has been studied. When the nonmetals content was 25 wt% and the particle size group was 0.07-0.09 mm, the NMA had a viscosity of 1225 cP at 135 degrees C, a penetration of 53.7 dmm at 15 degrees C, a ring and ball softening point of 54 degrees C, a ductility of 43.5 cm at 15 degrees C, a G*/sin delta of 3995.27 Pa at 60 degrees C, and an upper limit temperature (G*/sin delta = 1 kPa) of 69.4 degrees C, all of which showed that the high temperature performance of asphalt was improved significantly. Therefore, this study gives a fundamental understanding of NMA and represents a novel attempt to deal with the fast increasing quantities of nonmetals from waste PCBs, which is significant from an environmental and economic standpoint.

  10. 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.

  11. 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.

  12. 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.

  13. Pyrolysis characteristics of the mixture of printed circuit board scraps and coal powder.

    Science.gov (United States)

    Hao, Juan; Wang, Haifeng; Chen, Shuhe; Cai, Bin; Ge, Linhan; Xia, Wencheng

    2014-10-01

    Thermogravimetric (TG) analysis and infrared spectroscopy were used to analyze the pyrolysis characteristics of printed circuit board scraps (PCBs), coal powder and their mixtures under nitrogen atmosphere. The experimental results show that there is a large difference between waste PCBs and coal powder in pyrolysis processing. The pyrolysis properties of the mixing samples are the result of interaction of the PCBs and coal powder, which is influenced by the content of mixture. The degree of pyrolysis and pyrolysis properties of the mixture are much better than that of the single component. The TG and the differential thermogravimetric (DTG) curves of the PCBs mixed with coal powder move towards the high-temperature zone with increasing amount of coal powder and subsequently the DTG peak also becomes wider. The Coats-Redfern integral method was used to determine the kinetic parameters of pyrolysis reaction mechanism with the different proportion of mixture. The gas of pyrolysis mainly composes of CO2, CO, H2O and some hydrocarbon. The bromide characteristic absorption peak has been detected obviously in the pyrolysis gas of PCBs. On the contrary, the absorption peak of the bromide is not obvious in pyrolysis gas of the PCBs samples adding 40% coal powder.

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

    Science.gov (United States)

    Quan, Cui; Li, Aimin; Gao, Ningbo

    2010-07-15

    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 degrees 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 approximately 338 nm and wall thickness of approximately 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 m(2)/g. The mechanism of the formation of the CNTs and porous carbons was discussed.

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

    Science.gov (United States)

    Ortuño, Nuria; Conesa, Juan A; 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 WHO2005-TEQ/kg sample, corresponding to the sample with and without metals, respectively.

  16. 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.

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    Waldir A. Bizzo

    2014-06-01

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

  19. 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.

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

    Science.gov (United States)

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

    2011-02-15

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

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

    Science.gov (United States)

    Zhao, Chunhu; Zhang, Xiaoping; Shi, Lin

    2017-03-01

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

  2. 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.

  3. 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.

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

    Science.gov (United States)

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

    2006-04-01

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

  5. 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.

  6. 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...

  7. 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。

  8. [Characterization of pyrolysis of waste printed circuit boards by high-resolution pyrolysis gas chromatography-mass spectrometry].

    Science.gov (United States)

    Zhang, Yanhong; Huang, Hong; Xia, Zhengbin; Chen, Huanqin

    2008-07-01

    Thermal degradation of pyrolysis of waste circuit boards was investigated by high-resolution pyrolysis gas chromatography-mass spectrometry (PyGC-MS) and thermogravimetry (TG). In helium atmosphere, the products of FR-4 waste printed circuit board were pyrolyzed at 350, 450, 550, 650, and 750 degrees degrees C, separately, and the pyrolysis products were identified by online MS. The results indicated that the pyrolysis products of the FR-4 waste circuit board were three kinds of substances, such as the low boiling point products, phenol, bisphenol and their related products. Moreover, under 300 degrees degrees C, only observed less pyrolysis products. As the increase of pyrolysis temperature, the relative content of the low boiling point products increased. In the range of 450-650 degrees degrees C, the qualitative analysis and character were similar, and the relative contents of phenol and bisphenol were higher. The influence of pyrolysis temperature on pyrolyzate yields was studied. On the basis of the pyrolyzate profile and the dependence of pyrolyzate yields on pyrolysis temperature, the thermal degradation mechanism of brominated epoxy resin was proposed.

  9. Analytical modeling of multi-layered printed circuit board using multi-stacked via clusters as component heat spreader

    Directory of Open Access Journals (Sweden)

    Monier-Vinard Eric

    2016-01-01

    Full Text Available In order to help the electronic designer to early determine the limits of the power dissipation of electronic component, an analytical model was established to allow a fast insight of relevant design parameters of a multi-layered electronic board constitution. The proposed steady-state approach based on Fourier series method promotes a practical solution to quickly investigate the potential gain of multi-layered thermal via clusters. Generally, it has been shown a good agreement between the results obtained by the proposed analytical model and those given by electronics cooling software widely used in industry. Some results highlight the fact that the conventional practices for Printed Circuit Board modeling can be dramatically underestimate source temperatures, in particular with smaller sources. Moreover, the analytic solution could be applied to optimize the heat spreading in the board structure with a local modification of the effective thermal conductivity layers.

  10. 印制电路板的防抄板技术及实现方法%Anti-copy board technology and implementation of printed circuit boards

    Institute of Scientific and Technical Information of China (English)

    张松; 张亚

    2015-01-01

    嵌入式系统的快速发展要求设计者必须将印制电路板做到高精度、高密度和高可靠性,这对设计者是一个很大的挑战。与此同时,黑客技术的迅速发展与芯片解剖技术的逐渐成熟,使得嵌入式系统所面临的各种攻击也越来越多,随之而生的印制电路板抄板技术也很快的引起了广大电路板设计者的重视。文章提出的印制电路板硬件的防抄板措施以及其核心芯片加密的实现方法,可以非常有效的应对各类抄板问题。%The rapid development of embedded systems requires the designer must be printed circuit board to do high precision, high density and high reliability,this is a big chall-enge to designers.At the same time,the development of hacking and anatomy of the chip technology,allows embedded systems are facing more and more attacks.With raw copy board technology has also caused the attention of the product designers.The artic-le puts forward the prevent printed circuit board hardware copy plate measures and the realization method of the core chip encryption,can be very effective to deal with all kinds of copy board problem.

  11. 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.

  12. Recovery of materials from waste printed circuit boards by vacuum pyrolysis and vacuum centrifugal separation.

    Science.gov (United States)

    Zhou, Yihui; Wu, Wenbiao; Qiu, Keqiang

    2010-11-01

    In this research, a two-step process consisting of vacuum pyrolysis and vacuum centrifugal separation was employed to treat waste printed circuit boards (WPCBs). Firstly, WPCBs were pyrolysed under vacuum condition at 600 °C for 30 min in a lab-scale reactor. Then, the obtained pyrolysis residue was heated under vacuum until the solder was melted, and then the molten solder was separated from the pyrolysis residue by the centrifugal force. The results of vacuum pyrolysis showed that the type-A of WPCBs (the base plates of which was made from cellulose paper reinforced phenolic resin) pyrolysed to form an average of 67.97 wt.% residue, 27.73 wt.% oil, and 4.30 wt.% gas; and pyrolysis of the type-B of WPCBs (the base plates of which was made from glass fiber reinforced epoxy resin) led to an average mass balance of 72.20 wt.% residue, 21.45 wt.% oil, and 6.35 wt.% gas. The results of vacuum centrifugal separation showed that the separation of solder was complete when the pyrolysis residue was heated at 400 °C, and the rotating drum was rotated at 1200 rpm for 10 min. The pyrolysis oil and gas can be used as fuel or chemical feedstock after treatment. The pyrolysis residue after solder separation contained various metals, glass fibers and other inorganic materials, which could be recycled for further processing. The recovered solder can be reused directly and it can also be a good resource of lead and tin for refining.

  13. 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.

  14. Capacitive and Inductive Parasitic Effects Determination, Due to the Traces in a Printed Circuit Board, when Using a π Type Filter

    OpenAIRE

    Uribe-Cruz O.; Peña-Rivero R.

    2011-01-01

    In this work the parasitic capacitive and inductive effects due to the strip lines in a printed circuit board are calculated. To find their values a MatLab code program was implemented and validated solving the electric equivalent circuit using the commercial software called Serenade. In this research a second order π-type filter was used in a commercial single-layer printedcircuit board.

  15. Scalable, Lightweight, Integrated and Quick-to-Assemble (SLIQ) Hyperdrives for Functional Circuit Dissection.

    Science.gov (United States)

    Liang, Li; Oline, Stefan N; Kirk, Justin C; Schmitt, Lukas Ian; Komorowski, Robert W; Remondes, Miguel; Halassa, Michael M

    2017-01-01

    Independently adjustable multielectrode arrays are routinely used to interrogate neuronal circuit function, enabling chronic in vivo monitoring of neuronal ensembles in freely behaving animals at a single-cell, single spike resolution. Despite the importance of this approach, its widespread use is limited by highly specialized design and fabrication methods. To address this, we have developed a Scalable, Lightweight, Integrated and Quick-to-assemble multielectrode array platform. This platform additionally integrates optical fibers with independently adjustable electrodes to allow simultaneous single unit recordings and circuit-specific optogenetic targeting and/or manipulation. In current designs, the fully assembled platforms are scalable from 2 to 32 microdrives, and yet range 1-3 g, light enough for small animals. Here, we describe the design process starting from intent in computer-aided design, parameter testing through finite element analysis and experimental means, and implementation of various applications across mice and rats. Combined, our methods may expand the utility of multielectrode recordings and their continued integration with other tools enabling functional dissection of intact neural circuits.

  16. Scalable, Lightweight, Integrated and Quick-to-Assemble (SLIQ) Hyperdrives for Functional Circuit Dissection

    Science.gov (United States)

    Liang, Li; Oline, Stefan N.; Kirk, Justin C.; Schmitt, Lukas Ian; Komorowski, Robert W.; Remondes, Miguel; Halassa, Michael M.

    2017-01-01

    Independently adjustable multielectrode arrays are routinely used to interrogate neuronal circuit function, enabling chronic in vivo monitoring of neuronal ensembles in freely behaving animals at a single-cell, single spike resolution. Despite the importance of this approach, its widespread use is limited by highly specialized design and fabrication methods. To address this, we have developed a Scalable, Lightweight, Integrated and Quick-to-assemble multielectrode array platform. This platform additionally integrates optical fibers with independently adjustable electrodes to allow simultaneous single unit recordings and circuit-specific optogenetic targeting and/or manipulation. In current designs, the fully assembled platforms are scalable from 2 to 32 microdrives, and yet range 1–3 g, light enough for small animals. Here, we describe the design process starting from intent in computer-aided design, parameter testing through finite element analysis and experimental means, and implementation of various applications across mice and rats. Combined, our methods may expand the utility of multielectrode recordings and their continued integration with other tools enabling functional dissection of intact neural circuits. PMID:28243194

  17. Large-scale chemical assembly of atomically thin transistors and circuits

    Science.gov (United States)

    Zhao, Mervin; Ye, Yu; Han, Yimo; Xia, Yang; Zhu, Hanyu; Wang, Siqi; Wang, Yuan; Muller, David A.; Zhang, Xiang

    2016-11-01

    Next-generation electronics calls for new materials beyond silicon, aiming at increased functionality, performance and scaling in integrated circuits. In this respect, two-dimensional gapless graphene and semiconducting transition-metal dichalcogenides have emerged as promising candidates due to their atomic thickness and chemical stability. However, difficulties with precise spatial control during their assembly currently impede actual integration into devices. Here, we report on the large-scale, spatially controlled synthesis of heterostructures made of single-layer semiconducting molybdenum disulfide contacting conductive graphene. Transmission electron microscopy studies reveal that the single-layer molybdenum disulfide nucleates at the graphene edges. We demonstrate that such chemically assembled atomic transistors exhibit high transconductance (10 µS), on-off ratio (˜106) and mobility (˜17 cm2 V-1 s-1). The precise site selectivity from atomically thin conducting and semiconducting crystals enables us to exploit these heterostructures to assemble two-dimensional logic circuits, such as an NMOS inverter with high voltage gain (up to 70).

  18. Flexible hybrid circuit fully inkjet-printed: Surface mount devices assembled by silver nanoparticles-based inkjet ink

    Science.gov (United States)

    Arrese, J.; Vescio, G.; Xuriguera, E.; Medina-Rodriguez, B.; Cornet, A.; Cirera, A.

    2017-03-01

    Nowadays, inkjet-printed devices such as transistors are still unstable in air and have poor performances. Moreover, the present electronics applications require a high degree of reliability and quality of their properties. In order to accomplish these application requirements, hybrid electronics is fulfilled by combining the advantages of the printing technologies with the surface-mount technology. In this work, silver nanoparticle-based inkjet ink (AgNP ink) is used as a novel approach to connect surface-mount devices (SMDs) onto inkjet-printed pads, conducted by inkjet printing technology. Excellent quality AgNP ink-junctions are ensured with high resolution picoliter drop jetting at low temperature (˜150 °C). Electrical, mechanical, and morphological characterizations are carried out to assess the performance of the AgNP ink junction. Moreover, AgNP ink is compared with common benchmark materials (i.e., silver epoxy and solder). Electrical contact resistance characterization shows a similar performance between the AgNP ink and the usual ones. Mechanical characterization shows comparable shear strength for AgNP ink and silver epoxy, and both present higher adhesion than solder. Morphological inspections by field-emission scanning electron microscopy confirm a high quality interface of the silver nanoparticle interconnection. Finally, a flexible hybrid circuit on paper controlled by an Arduino board is manufactured, demonstrating the viability and scalability of the AgNP ink assembling technique.

  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. Optimal production planning for PCB assembly

    CERN Document Server

    Ho, William

    2006-01-01

    Focuses on the optimization of the Printed circuit board (PCB) assembly lines' efficiency. This book integrates the component sequencing and the feeder arrangement problems together for the pick-and-place machine and the chip shooter machines.

  2. 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

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

    Science.gov (United States)

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

    2014-10-01

    The rapid consumption and obsolescence of electronics have resulted in e-waste being one of the fastest growing waste streams worldwide. Printed circuit boards (PCBs) are among the most complex e-waste, containing significant quantities of hazardous and toxic materials leading to high levels of pollution if landfilled or processed inappropriately. However, PCBs are also an important resource of metals including copper, tin, lead and precious metals; their recycling is appealing especially as the concentration of these metals in PCBs is considerably higher than in their ores. This article is focused on a novel approach to recover copper rich phases from waste PCBs. Crushed PCBs were heat treated at 1150°C under argon gas flowing at 1L/min into a horizontal tube furnace. Samples were placed into an alumina crucible and positioned in the cold zone of the furnace for 5 min to avoid thermal shock, and then pushed into the hot zone, with specimens exposed to high temperatures for 10 and 20 min. After treatment, residues were pulled back to the cold zone and kept there for 5 min to avoid thermal cracking and re-oxidation. This process resulted in the generation of a metallic phase in the form of droplets and a carbonaceous residue. The metallic phase was formed of copper-rich red droplets and tin-rich white droplets along with the presence of several precious metals. The carbonaceous residue was found to consist of slag and ∼30% carbon. The process conditions led to the segregation of hazardous lead and tin clusters in the metallic phase. The heat treatment temperature was chosen to be above the melting point of copper; molten copper helped to concentrate metallic constituents and their separation from the carbonaceous residue and the slag. Inert atmosphere prevented the re-oxidation of metals and the loss of carbon in the gaseous fraction. Recycling e-waste is expected to lead to enhanced metal recovery, conserving natural resources and providing an environmentally

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

    Science.gov (United States)

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

    2014-09-01

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

  5. Short-Circuit Tests and Simulations with a SCFCL Modular Assembly

    Science.gov (United States)

    Sousa, W. T. B. de; Polasek, A.; Dias, R.; Silva, F. A.; Lopes, F. C.; Filho, O. Orsino; de Andrade, R.

    Short-circuit tests and simulations carried out with a resistive SCFCL modular assembly are presented. Each SCFCL moduleconsistsofaBSCCO2212bulkcoilwithacritical currentofabout520Aat77K.Seriesandparallel connection were tested. In series connection, prospectivecurrent as high as 67 kArms was limited to about 11 kApeak in the first peak. In parallel connection, prospective current as high as 65 kArms was limited to about 20 kApeak in the first peak. Low fault current tests were also carried out (current peaksof about3Ic)and in this case the SCFCL module takes more time to actuate, being considered satisfactory for "inrush" currents. Computational simulations were done considering the bulk coil E-J curve and heat transfers between SCFCL components and the LN2 bath. The simulations can reasonably predict the performance of the SCFCL assembly and provide additional information such as the temperature rise of superconductor and shunt.

  6. 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.

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

    Science.gov (United States)

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

    2014-03-01

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

  8. Ultra-thin and low-power optical interconnect module based on a flexible optical printed circuit board

    Science.gov (United States)

    Hwang, Sung Hwan; Lee, Woo-Jin; Kim, Myoung Jin; Jung, Eun Joo; Kim, Gye Won; An, Jong Bae; Jung, Ki Young; Cha, Kyung Soon; Rho, Byung Sup

    2012-07-01

    We describe an ultra-thin and low-power optical interconnect module for mobile electronic devices such as mobile phones and notebooks. The module was fabricated by directly packaging optic and electronic components onto a thin and flexible optical printed circuit board having a size of 70×8×0.25 mm. The completed active module has features of thinness (0.5 mm), small size (7×5 mm), very low total power consumption (15.88 mW), and high data rate transmissions (2.5 Gbps).

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

    Science.gov (United States)

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

    2014-11-01

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

  10. 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.

  11. 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.

  12. Removing lead from metallic mixture of waste printed circuit boards by vacuum distillation: factorial design and removal mechanism.

    Science.gov (United States)

    Li, Xingang; Gao, Yujie; Ding, Hui

    2013-10-01

    The lead removal from the metallic mixture of waste printed circuit boards by vacuum distillation was optimized using experimental design, and a mathematical model was established to elucidate the removal mechanism. The variables studied in lead evaporation consisted of the chamber pressure, heating temperature, heating time, particle size and initial mass. The low-level chamber pressure was fixed at 0.1 Pa as the operation pressure. The application of two-level factorial design generated a first-order polynomial that agreed well with the data for evaporation efficiency of lead. The heating temperature and heating time exhibited significant effects on the efficiency, which was validated by means of the copper-lead mixture experiments. The optimized operating conditions within the region studied were the chamber pressure of 0.1 Pa, heating temperature of 1023 K and heating time of 120 min. After the conditions were employed to remove lead from the metallic mixture of waste printed circuit boards, the efficiency was 99.97%. The mechanism of the effects was elucidated by mathematical modeling that deals with evaporation, mass transfer and condensation, and can be applied to a wider range of metal removal by vacuum distillation.

  13. 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.

  14. Impaired activity-dependent neural circuit assembly and refinement in autism spectrum disorder genetic models

    Directory of Open Access Journals (Sweden)

    Caleb Andrew Doll

    2014-02-01

    Full Text Available Early-use activity during circuit-specific critical periods refines brain circuitry by the coupled processes of eliminating inappropriate synapses and strengthening maintained synapses. We theorize these activity-dependent developmental processes are specifically impaired in autism spectrum disorders (ASDs. ASD genetic models in both mouse and Drosophila have pioneered our insights into normal activity-dependent neural circuit assembly and consolidation, and how these developmental mechanisms go awry in specific genetic conditions. The monogenic Fragile X syndrome (FXS, a common cause of heritable ASD and intellectual disability, has been particularly well linked to defects in activity-dependent critical period processes. The Fragile X Mental Retardation Protein (FMRP is positively activity-regulated in expression and function, in turn regulates excitability and activity in a negative feedback loop, and appears to be required for the activity-dependent remodeling of synaptic connectivity during early-use critical periods. The Drosophila FXS model has been shown to functionally conserve the roles of human FMRP in synaptogenesis, and has been centrally important in generating our current mechanistic understanding of the FXS disease state. Recent advances in Drosophila optogenetics, transgenic calcium reporters, highly-targeted transgenic drivers for individually-identified neurons, and a vastly improved connectome of the brain are now being combined to provide unparalleled opportunities to both manipulate and monitor activity-dependent processes during critical period brain development in defined neural circuits. The field is now poised to exploit this new Drosophila transgenic toolbox for the systematic dissection of activity-dependent mechanisms in normal versus ASD brain development, particularly utilizing the well-established Drosophila FXS disease model.

  15. 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

  16. Evolving circuits in seconds: experiments with a stand-alone board-level evolvable system

    Science.gov (United States)

    Stoica, A.; Zebulum, R. S.; Ferguson, M. I.; Keymeulen, D.; Duong, V.; Guo, X.

    2002-01-01

    The purpose of this paper is twofold: first, to illustrate a stand-alone board-level evolvable system (SABLES) and its performance, and second to illustrate some problems that occur during evolution with real hardware in the loop, or when the intention of the user is not completely reflected in the fitness function.

  17. Three-dimensional integration of power electronic converters on printed circuit board

    OpenAIRE

    de Jong, E.C.W.

    2007-01-01

    The current construction technology for PCB assembled power converters is based on the assembly of pre-manufactured discrete components. Fundamental limits of this construction method are steadily being reached as power converters tend to exploit higher processing speeds to gain advantages in both magnetic component size and overall power density. This thesis investigates a new design approach encompassing thermal management, geometrical packaging and electromagnetic integration (focussing on...

  18. Embedding electromagnetic band gap structures in printed circuit boards for electromagnetic interference reduction

    NARCIS (Netherlands)

    Tereshchenko, Olga Victorivna

    2015-01-01

    Due to the tendency of faster data rates and lower power supply voltage in the integrated circuit (IC) design, Simultaneously Switching Noise (SSN) and ground bounce become serious concerns for designers and testers. This noise can be a source of electromagnetic interference (EMI). It propagates thr

  19. 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.

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

    Science.gov (United States)

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

    2014-05-01

    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. Identification and chemical characterization of particulate matter from wave soldering processes at a printed circuit board manufacturing company.

    Science.gov (United States)

    Szoboszlai, Z; Kertész, Zs; Szikszai, Z; Angyal, A; Furu, E; Török, Zs; Daróczi, L; Kiss, A Z

    2012-02-15

    In this case study, the elemental composition and mass size distribution of indoor aerosol particles were determined in a working environment where soldering of printed circuit boards (PCB) took place. Single particle analysis using ion and electron microscopy was carried out to obtain more detailed and reliable data about the origin of these particles. As a result, outdoor and indoor aerosol sources such as wave soldering, fluxing processes, workers' activity, mineral dust, biomass burning, fertilizing and other anthropogenic sources could be separated. With the help of scanning electron microscopy, characteristic particle types were identified. On the basis of the mass size distribution data, a stochastic lung deposition model was used to calculate the total and regional deposition efficiencies of the different types of particles within the human respiratory system. The information presented in this study aims to give insights into the detailed characteristics and the health impact of aerosol particles in a working environment where different kinds of soldering activity take place.

  2. 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.

  3. 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.

  4. 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.

  5. Effect of ionic contamination on climatic reliability of printed circuit board assemblies

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2012-01-01

    . The investigations were performed under environmental conditions varying from non-condensation with 60% RH at 25°C to near to condensation with 98% RH at 25°C, and full condensation conditions. Near to condensation and full condensation conditions have been established by (i) lowering the temperature of PCBA while...

  6. 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

    , 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 an appropriate cleaning. Selective soldering process generates significantly higher levels of residues compared to the wave and reflow process. For conformal coated PCBAs, the contamination levels generated from the tested wave and selective soldering process are found to be enough to generate blisters under...

  7. Wideband vibrational electromagnetic energy harvesters with nonlinear polyimide springs based on rigid-flex printed circuit boards technology

    Science.gov (United States)

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

    2016-12-01

    A wideband vibrational electromagnetic energy harvester employing nonlinear spring effects is proposed and demonstrated. The harvesters were designed and fabricated by commercial rigid-flex printed circuit boards technology. Rigid FR-4 boards were used for mechanical support and coil winding, whereas flexible polyimide films were patterned for mechanical springs and mass platforms. Two sets of coils were patterned and fabricated in the harvester with an internal coil resistance of about 16 Ω each. Two rare-earth magnets were attached to the central platform as shuttle mass. The total dimension of the harvester was 20 × 20 × 4 mm3. In vibration tests, nonlinearity could be observed even at 0.1 grms vibration level due to the spring hardening effect. The frequency for peak induced voltage increased from 187 Hz at low vibration to 382 Hz at 5 grms vibration. The effective half-power bandwidth increased from 8 Hz at 0.1 grms to 32 Hz at 1 grms and 52 Hz at 5 grms due to the hysteresis in frequency response. For a matched load and 1 grms vibration at 250 Hz, the maximum output power was 160 nW, corresponding to a power density of 100 nW cm-3.

  8. 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 Multimedia

    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).

  9. Surface Breakdown of Printed Circuit Board under Magnetic Field with Reduced Pressure

    Institute of Scientific and Technical Information of China (English)

    杜伯学; 朱晓辉; 高宇; 卢欣

    2010-01-01

    Epoxy resin laminate onto which a pair of copper foil was printed was employed as test samples.The samples were placed in an artificial atmospheric chamber, which was vacuumed by a rotary pump from 100 kPa to 5 kPa.The magnetic field was produced by permanent magnets that were assembled to make E×B drift away from, into and parallel to the sample surface, respectively.Magnetic flux density was adjusted at 120 mT, 180 mT and 240 mT respectively.By applying a negative bias voltage between the electrodes, the ...

  10. 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.

  11. 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.

  12. 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

    2017-02-01

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

  13. 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.

  14. 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.

  15. An Overview of Surface Finishes and Their Role in Printed Circuit Board Solderability and Solder Joint Performance

    Energy Technology Data Exchange (ETDEWEB)

    Vianco, P.T.

    1998-10-15

    A overview has been presented on the topic of alternative surface finishes for package I/Os and circuit board features. Aspects of processability and solder joint reliability were described for the following coatings: baseline hot-dipped, plated, and plated-and-fused 100Sn and Sn-Pb coatings; Ni/Au; Pd, Ni/Pd, and Ni/Pd/Au finishes; and the recently marketed immersion Ag coatings. The Ni/Au coatings appear to provide the all-around best option in terms of solderability protection and wire bondability. Nickel/Pal ftishes offer a slightly reduced level of performance in these areas that is most likely due to variable Pd surface conditions. It is necessmy to minimize dissolved Au or Pd contents in the solder material to prevent solder joint embrittlement. Ancillary aspects that included thickness measurement techniques; the importance of finish compatibility with conformal coatings and conductive adhesives; and the need for alternative finishes for the processing of non-Pb bearing solders were discussed.

  16. 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 %.

  17. Determination of the potential gold electrowinning from an ammoniacal thiosulphate solution applied to recycling of printed circuit board scraps.

    Science.gov (United States)

    Kasper, Angela C; Carrillo Abad, Jordi; García Gabaldón, Montserrat; Veit, Hugo M; Pérez Herranz, Valentín

    2016-01-01

    The use of electrochemical techniques in the selective recovery of gold from a solution containing thiosulphate, ammonia, and copper, obtained from the leaching of printed circuit boards from mobile phones using ammoniacal thiosulphate, are shown in this work. First, cyclic voltammetry tests were performed to determine the potential of electrodeposition of gold and copper, and then, electrowinning tests at different potentials for checking the rates of recovery of these metals were performed. The results of the cyclic voltammetry show that copper deposition occurs at potentials more negative than -600 mV (Ag/AgCl), whereas the gold deposition can be performed at potentials more positives than -600 mV (Ag/AgCl). The results of electrowinning show that 99% of the gold present in solutions containing thiosulphate and copper can be selectively recovered in a potential range between -400 mV (vs Ag/AgCl) and -500 mV (vs Ag/AgCl). Furthermore, 99% of copper can be recovered in potentials more negative than -700 mV (vs Ag/AgCl).

  18. Recovery of metals from waste printed circuit boards by supercritical water pre-treatment combined with acid leaching process.

    Science.gov (United States)

    Xiu, Fu-Rong; Qi, Yingying; Zhang, Fu-Shen

    2013-05-01

    Waste printed circuit boards (PCBs) contain a large number of metals such as Cu, Sn, Pb, Cd, Cr, Zn, and Mn. In this work, an efficient and environmentally friendly process for metals recovery from waste PCBs by supercritical water (SCW) pre-treatment combined with acid leaching was developed. In the proposed process, waste PCBs were pre-treated by SCW, then the separated solid phase product with concentrated metals was subjected to an acid leaching process for metals recovery. The effect of SCW pre-treatment on the recovery of different metals from waste PCBs was investigated. Two methods of SCW pre-treatment were studied: supercritical water oxidation (SCWO) and supercritical water depolymerization (SCWD). Experimental results indicated that SCWO and SCWD pre-treatment had significant effect on the recovery of different metals. SCWO pre-treatment was highly efficient for enhancing the recovery of Cu and Pb, and the recovery efficiency increased significantly with increasing pre-treatment temperature. The recovery efficiency of Cu and Pb for SCWO pre-treatment at 420°C was 99.8% and 80%, respectively, whereas most of the Sn and Cr were immobilized in the residue. The recovery of all studied metals was enhanced by SCWD pre-treatment and increased along with pre-treatment temperature. Up to 90% of Sn, Zn, Cr, Cd, and Mn could be recovered for SCWD pre-treatment at 440°C.

  19. Electrokinetic recovery of Cd, Cr, As, Ni, Zn and Mn from waste printed circuit boards: effect of assisting agents.

    Science.gov (United States)

    Xiu, Fu-Rong; Zhang, Fu-Shen

    2009-10-15

    The printed circuit boards (PCBs) contains large number of heavy metal such as Cd, Cr, As, Ni, Zn and Mn. In this study, the use of electrokinetic (EK) treatment with different assisting agents has been investigated to recover the heavy metals from waste PCBs, and the effectiveness of different assisting agents (HNO(3), HCl, citric acid) was evaluated. The PCBs were first pre-treated by supercritical water oxidation (SCWO) process, then subjected to EK process. The heavy metal speciation, migration and recovery efficiency in the presence of different assisting agents during EK process were discussed. The mass loss of Cd, Cr, As and Zn during the SCWO process was negligible, but approximately 52% of Ni and 56% of Mn were lost in such a process. Experimental results showed that different assisting agents have significant effect on the behavior and recovery efficiency of different heavy metals. HCl was highly efficient for the recovery of Cd in waste PCBs due to the low pH and the stable complexation of Cl(-). Citric acid was highly efficient for the recovery of Cr, Zn and Mn. HNO(3) was low efficient for recovery of most heavy metals except for Ni.

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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

    2016-09-05

    In this study, a novel reutilization method for waste printed circuit boards (PCBs) as flame retardant and smoke suppressant for poly (vinyl chloride) (PVC) was successfully testified. A supercritical water oxidation (SCWO) process was applied to treat waste PCBs before they could be used as flame retardants of PVC. The results indicated that SCWO conditions had a significant effect on the flame retarding and smoke suppressing properties of waste PCBs for PVC. Cu2O, CuO, and SnO2 were the main active ingredients in waste PCBs-derived flame retardants. A conversion of Cu elements (Cu(0)→Cu(+)→Cu(2+)) during SCWO process with the increase of reaction temperature was found to be the key influence factor for the flame retarding properties of SCWO-treated PCBs. The experiment results also showed that there was a synergistic effect of flame retardancy between Cu(+) and Cu(2+). After the optimized SCWO treatment, SCWO-treated PCBs significantly improved the flame retardancy and smoke suppression of PVC. Limiting oxygen index (LOI) and char yield (CY) increased with increasing SCWO-treated PCBs content in PVC, while smoke density rating (SDR) and maximum smoke density (MSD) decreased markedly. The mechanical properties of PVC samples were influenced in different degree by adding different content SCWO-treated PCBs.

  6. 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.

  7. Recycling of organic materials and solder from waste printed circuit boards by vacuum pyrolysis-centrifugation coupling technology.

    Science.gov (United States)

    Zhou, Yihui; Wu, WenBiao; Qiu, Keqiang

    2011-12-01

    Here, we focused on the recycling of waste printed circuit boards (WPCBs) using vacuum pyrolysis-centrifugation coupling technology (VPCT) aiming to obtain valuable feedstock and resolve environmental pollution. The two types of WPCBs were pyrolysed at 600°C for 30 min under vacuum condition. During the pyrolysis process, the solder of WPCBs was separated and recovered when the temperature range was 400-600°C, and the rotating drum was rotated at 1000 rpm for 10 min. The type-A of WPCBs pyrolysed to form an average of 67.91 wt.% residue, 27.84 wt.% oil, and 4.25 wt.% gas; and pyrolysis of the type-B of WPCBs led to an average mass balance of 72.22 wt.% residue, 21.57 wt.% oil, and 6.21 wt.% gas. The GC-MS and FT-IR analyses showed that the two pyrolysis oils consisted mainly of phenols and substituted phenols. The pyrolysis oil can be used for fuel or chemical feedstock for further processing. The recovered solder can be recycled directly and it can also be a good resource of lead and tin for refining. The pyrolysis residues contained various metals, glass fibers and other inorganic materials, which could be recovered after further treatment. The pyrolysis gases consisted mainly of CO, CO(2), CH(4), and H(2), which could be collected and recycled.

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

    Science.gov (United States)

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

    2012-11-01

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

  9. 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.

  10. Study of the transference rules for bromine in waste printed circuit boards during microwave-induced pyrolysis.

    Science.gov (United States)

    Sun, Jing; Wang, Wenlong; Liu, Zhen; Ma, Chunyuan

    2011-05-01

    The production of waste printed circuit boards (WPCBs) has drawn increasing global concern, especially because the high bromine (Br) content (5-15%) places obstacles in the way of simple disposal techniques. Microwave-induced pyrolysis of WPCBs provides a promising way to dispose of these hazardous and resource-filled wastes. The transference rules for Br during microwave-induced pyrolysis have been investigated experimentally. It was found that the microwave energy could be used more efficiently to accelerate the heating rate and improve the final pyrolysis temperature by adding some activated carbon (AC) as microwave absorbents. The high temperature and rapid pyrolysis process promoted the yields of gaseous products and the decomposition of brominated compounds into hydrogen bromide and then benefited the capture of Br and the debromination of byproducts. The application of a calcium carbonate (CaCO3) layer overhead led to over 95% debromination of the liquid products and over 50% capture of the total Br. It can be concluded that the presented method is suitable for the control of Br transference in the recycling of WPCBs. This method can also be extended to the disposal of the electronic scraps.

  11. 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.

  12. Zinc Oxide Nanorods Grown on Printed Circuit Board for Extended-Gate Field-Effect Transistor pH Sensor

    Science.gov (United States)

    Van Thanh, Pham; Nhu, Le Thi Quynh; Mai, Hong Hanh; Tuyen, Nguyen Viet; Doanh, Sai Cong; Viet, Nguyen Canh; Kien, Do Trung

    2017-02-01

    Zinc oxide (ZnO) nanorods (NRs) were grown directly on printed circuit boards with a 35-μm-thick copper layer using a seedless galvanic-cell hydrothermal process. The hexagonal structure of the synthesized ZnO NRs was observed by scanning electron microscopy. The microstructural characteristics of the as-grown ZnO NRs were investigated by x-ray diffraction analysis, revealing preferred (002) growth direction. Raman and photoluminescence spectra confirmed the high crystalline quality of the ZnO NRs. As-grown ZnO NRs were then grown for 7 h using the galvanic effect for use as the pH membrane of an extended-gate field-effect transistor pH sensor (pH-EGFET). The current-voltage characteristics showed sensitivity of 15.4 mV/pH and 0.26 (μA)1/2/pH in the linear and saturated region, respectively. Due to their cost effectiveness, low-temperature processing, and ease of fabrication, such devices are potential candidates for use as flexible, low-cost, disposable biosensors.

  13. Morphology, mechanical and thermal oxidative aging properties of HDPE composites reinforced by nonmetals recycled from waste printed circuit boards.

    Science.gov (United States)

    Yang, Shuangqiao; Bai, Shibing; Wang, Qi

    2016-11-01

    In this study nonmetals recycled from waste printed circuit boards (NPCB) is used as reinforce fillers in high-density polyethylene (HDPE) composites. The morphology, mechanical and thermal oxidative aging properties of NPCB reinforced HDPE composites are assessed and it compared with two other commercial functional filler for the first time. Mechanical test results showed that NPCB could be used as reinforcing fillers in the HDPE composites and mechanical properties especially for stiffness is better than other two commercial fillers. The improved mechanical property was confirmed by the higher aspect ratio and strong interfacial adhesion in scanning electron microscopy (SEM) studies. The heat deflection temperature (HDT) test showed the presence of fiberglass in NPCB can improve the heat resistance of composite for their potential applications. Meanwhile, the oxidation induction time (OIT) and the Fourier transform infrared (FTIR) spectroscopy results showed that NPCB has a near resistance to oxidation as two other commercial fillers used in this paper. The above results show the reuse of NPCB in the HDPE composites represents a promising way for resolving both the environmental pollution and the high-value reuse of resources.

  14. Milk-run kanban system for raw printed circuit board withdrawal to surface-mounted equipment

    Directory of Open Access Journals (Sweden)

    Swee Li Chee

    2012-12-01

    Full Text Available Purpose:  The paper aims to present a case study and later simulation analysis on a kanban system that incorporating milk-run operation to draw in raw material to the process. Design/methodology/approach:  Data collection at the case study company for ten weeks followed by a process study called value stream mapping. The proposed kanban model is simulated to test its various performances including total output, average flow time, average work-in-process, SME utilization, and average waiting time. Response surface methodology is adopted to generate suitable representative regression models.  Findings: For all performance measures, simulation results showed that the proposed system consistently outperforms the push system currently practiced. Second, the system indicates the advantages of leveling, particularly in the event of machine failure and blockage. Third, operator in the proposed kanban system has a lower utilization, even with the additional material handling task.   Research limitations/implications: This study only begins to reveal the implication of leveling for production control on multi-machine scenario. The simulation of the system is solely based only the case study. The control parameters critical to the case study, were naturally used. The furtherance of the research should include generalizing the system and devising the respective methodology to facilitate wider applications. Practical implications: Originality/value:  The kanban system is proposed in the light of conflicting interests in handling the surface mounting and the related upstream processes. Such aspect is common to electronics assembly industry.

  15. 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.

  16. Research on Poka Yoke Methods in Circuit Board Test%电路板自动测试中的防差错技术研究

    Institute of Scientific and Technical Information of China (English)

    霍晓磊; 康霞; 谭业双

    2014-01-01

    ATS ( Automatic Test System) is a developing trend in the circuit board test. Error and mistake proofing is taken into con-sideration in the design of ATS. It directly affects its reliability, safety and efficiency, especial y, when many kinds of circuit boards exist in the system. Some kinds of typical measures are introduced in this paper. The specific design methods of adapter, circuit board and cable are described in detail.%自动测试是目前电路板测试发展的主要趋势,而防差错设计是自动测试系统设计时需要考虑的问题之一,尤其在被测单元种类很多的情况下,防差错设计直接影响到系统的可靠性、安全性和工作效率,更应该引起重视。根据实际工程经验着重阐述了电路板自动测试中所采取的防差错措施,描述了实际工程中适配器、电路板、电缆和软件防差错的实现方法。

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

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jinxiu; Chen, Mengjun, E-mail: kyling@swust.edu.cn; Chen, Haiyan; Chen, Shu; Sun, Quan

    2014-02-15

    Highlights: • A Brønsted acidic ILs was used to leach Cu from WPCBs for the first time. • The particle size of WPCBs has significant influence on Cu leaching rate. • Cu leaching rate was higher than 99% under the optimum leaching conditions. • The leaching process can be modeled with shrinking core model, and the E{sub a} was 25.36 kJ/mol. - Abstract: In this work, a Brønsted acidic ionic liquid, 1-butyl-3-methyl-imidazolium hydrogen sulfate ([bmim]HSO{sub 4}), was used to leach copper from waste printed circuit boards (WPCBs, mounted with electronic components) for the first time, and the leaching behavior of copper was discussed in detail. The results showed that after the pre-treatment, the metal distributions were different with the particle size: Cu, Zn and Al increased with the increasing particle size; while Ni, Sn and Pb were in the contrary. And the particle size has significant influence on copper leaching rate. Copper leaching rate was higher than 99%, almost 100%, when 1 g WPCBs powder was leached under the optimum conditions: particle size of 0.1–0.25 mm, 25 mL 80% (v/v) ionic liquid, 10 mL 30% hydrogen peroxide, solid/liquid ratio of 1/25, 70 °C and 2 h. Copper leaching by [bmim]HSO{sub 4} can be modeled with the shrinking core model, controlled by diffusion through a solid product layer, and the kinetic apparent activation energy has been calculated to be 25.36 kJ/mol.

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

    Energy Technology Data Exchange (ETDEWEB)

    Isakson, K.; Vessell, A.L.

    1994-07-01

    Fermilab is presently phasing out all solvents containing Freon-113 (CFC-113) as part of the continuing Waste Minimization Program. These solvents are used primarily in cleaning the flux off of electronic circuit boards after soldering, specifically in bench type work. Title VI of the Clean Air Act mandates a production phase-out for ozone depleting substances, like CFC-113, by the year 2000. Our study addresses this issue by evaluating and choosing alternative non-CFC solvents to replace the CFC-1 13 solvents at Fermilab. Several potential non-CFC cleaning solvents were tested. The evaluation took place in three parts: controlled experimental evaluation, chemical composition evaluation, and employee performed evaluation. First, we performed a controlled nine-step procedure with the potential solvents where each was evaluated in categories such as cleaning effectiveness, odor, residue, type of output and drying time. Next, we listed the chemical composition of each solvent. We noted which solvents contained hydrochlorofluorocarbons because they are targeted for phase-out in the future and will be recognized as interim solutions only. Finally, after preliminary testing, five solvents were chosen as the best options. These solvents were sent to be tested by Fermilab employees who use such materials. Their opinions are valuable not only because they are knowledgeable in this field, but also because they will be using the solvents chosen to replace the CFC-113 solvents. The results favored two ``best alternatives``: Safezone Solvent Flux Remover by Miller-Stephenson and E-Series CFC Free Flux-Off 2000 by Chemtech. Another possible solution also pursued is the no-clean solder option. In our study, we were not able to thoroughly investigate the many types of no-clean solders because of time and financial constraints. The testing that was done, however, showed that no-clean solder was a viable alternative in many cases.

  19. 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.

  20. 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.

  1. 废旧电路板中金的碘化法回收工艺%Gold recovery process with iodine method from waste printed circuit board

    Institute of Scientific and Technical Information of China (English)

    李桂春; 苑仁财; 康华; 王会平

    2012-01-01

    Aimed at recovering gold from waste printed circuit board, this paper proposes a crush-flotation-iodide leaching process. The process consists of crushing and classifying the waste printed circuit board, separating each particle size powder into metallic and nonmetallic, removing the base metal in metallic powder by nitric acid leaching, filtration, and recovering gold in the residue with iodine leaching method. Results show that metals and non-metals in the printed circuit boards exhibit a complete dissociation granularity of 0. 450 mm, the separation of less than 0. 450 mm printed circuit board powder by flo- tation process yields a mass fraction of sediment metals of 87.32%, and metal recovery of 90. 11%, and the iodine and iodide solutions gives effective leaching of the gold in the printed circuit boards powder within 3 h, with a leaching rate of 95.53%.%针对电路板中金的回收问题,提出粉碎一浮选一碘化浸出工艺。采用浮选法对经粉碎分级的电路板粉末进行分选实验,分选出的金属粉末用硝酸去除贱金属,过滤,由碘化法浸出滤渣中的金。实验结果表明:电路板中金属和非金属完全解离粒度为0.450mm;浮选分离小于0.450mm电路板粉末,沉物金属质量分数为87.32%,金属回收率为90.11%;碘和碘化物溶液可以在3h内有效浸出电路板粉末中的金,金浸出率为95.53%。

  2. Influence of polymer aging on reliability indices of a typical printed-circuit assembly of radioelectronic equipment

    Science.gov (United States)

    Kuznetsov, G. V.; Kravchenko, E. V.

    2007-09-01

    Mathematical modeling of nonlinear nonstationary temperature fields of a typical printed-circuit assembly of radioelectronic equipment has been performed in a three-dimensional formulation with account for the convective and radiative heat exchange with the environment. On the basis of the data of the numerical experiment the “aging” (degradation) indices of polymer materials under prolonged thermal action have been determined. It has been established that the reliability of an object modeled with account for the real temperature fields is five times lower compared to the realization of normalized thermal conditions.

  3. Design of Circuit Board Drilling Machine Control System Based on Motion Control Board%基于运动控制板长的电路板钻孔机控制系统设计

    Institute of Scientific and Technical Information of China (English)

    李德亮; 舒志兵

    2012-01-01

    钻孔是印制电路板(PCB)制造的关键工序之一.对于钻孔工序而言,影响孔壁质量的主要因素是钻头的转速和进给速度.介绍一种基于ADT850运动控制板卡的电路板钻孔机控制系统设计方案,着重介绍控制系统的硬件组成及基于VC++的软件构架.该系统采用光栅尺的检测信号作为反馈信号构成全闭环系统,提高了控制系统的加工精度.%Drilling is one of key processes in printed circuit board (PCB) manufacturing. During the drilling process, the main factors impacting hole-wall's quality are drilling speed and feeding rate. A circuit board drilling machine control system based on motion control board ADT850 were introduced, highlighting the control system's hardware composition and software architecture based on VC ++ . In the system, the detection signal of optical grating was used as feedback signal and an entire closed-loop system was constituted to enhance the control system's machining accuracy.

  4. Assembly and Thermal Hydraulic Test of a Stainless Steel Sodium-Potassium Circuit

    Science.gov (United States)

    Garber, A.; Godfroy, T.; Webster, K.

    2007-01-01

    Early Flight Fission Test Facilities (EFF-TF) team has been tasked by the NASA Marshall Space Flight Center Nuclear Systems Office to design, fabricate, and test an actively pumped alkali metal flow circuit. The system was originally built for use with lithium, but due to a shift in focus, it was redesigned for use with a eutectic mixture of sodium potassium (NaK). Basic circuit components include: reactor segment, NaK to gas heat exchanger, electromagnetic (EM) liquid metal pump, load/drain reservoir, expansion reservoir, instrumentation, and a spill reservoir. A 37-pin partial-array core (pin and flow path dimensions are the same as those in a full design) was selected for fabrication and test. This paper summarizes the first fill and checkout testing of the Stainless Steel NaK-Cooled Circuit (SNaKC).

  5. Stainless Steel NaK-Cooled Circuit (SNaKC) Fabrication and Assembly

    Science.gov (United States)

    Godfroy, Thomas J.

    2007-01-01

    An actively pumped Stainless Steel NaK Circuit (SNaKC) has been designed and fabricated by the Early Flight Fission Test Facility (EFF-TF) team at NASA's Marshall Space Flight Center. This circuit uses the eutectic mixture of sodium and potassium (NaK) as the working fluid building upon the experience and accomplishments of the SNAP reactor program from the late 1960's The SNaKC enables valuable experience and liquid metal test capability to be gained toward the goal of designing and building an affordable surface power reactor. The basic circuit components include a simulated reactor core a NaK to gas heat exchanger, an electromagnetic (EM) liquid metal pump, a liquid metal flow meter, an expansion reservoir and a drain/fill reservoir To maintain an oxygen free environment in the presence of NaK, an argon system is utilized. A helium and nitrogen system are utilized for core, pump, and heat exchanger operation. An additional rest section is available to enable special component testing m an elevated temperature actively pumped liquid metal environment. This paper summarizes the physical build of the SNaKC the gas and pressurization systems, vacuum systems, as well as instrumentation and control methods.

  6. Simulation of electronic circuit sensitivity towards humidity using electrochemical data on water layer

    DEFF Research Database (Denmark)

    Joshy, Salil; Verdingovas, Vadimas; Jellesen, Morten Stendahl

    2015-01-01

    Climatic conditions like temperature and humidity have direct influence on the operation of electronic circuits. The effects of temperature on the operation of electronic circuits have been widely investigated, while the effect of humidity and solder flux residues are not well understood including...... the effect on circuit and PCBA (printed circuit board assembly) layout design. This paper elucidates a methodology for analyzing the sensitivity of an electronic circuit based on parasitic circuit analysis using data on electrical property of the water layer formed under humid as well as contaminated...

  7. Effects of PCB Pad Metal Finishes on the Cu-Pillar/Sn-Ag Micro Bump Joint Reliability of Chip-on-Board (COB) Assembly

    Science.gov (United States)

    Kim, Youngsoon; Lee, Seyong; Shin, Ji-won; Paik, Kyung-Wook

    2016-06-01

    While solder bumps have been used as the bump structure to form the interconnection during the last few decades, the continuing scaling down of devices has led to a change in the bump structure to Cu-pillar/Sn-Ag micro-bumps. Cu-pillar/Sn-Ag micro-bump interconnections differ from conventional solder bump interconnections in terms of their assembly processing and reliability. A thermo-compression bonding method with pre-applied b-stage non-conductive films has been adopted to form solder joints between Cu pillar/Sn-Ag micro bumps and printed circuit board vehicles, using various pad metal finishes. As a result, various interfacial inter-metallic compounds (IMCs) reactions and stress concentrations occur at the Cu pillar/Sn-Ag micro bumps joints. Therefore, it is necessary to investigate the influence of pad metal finishes on the structural reliability of fine pitch Cu pillar/Sn-Ag micro bumps flip chip packaging. In this study, four different pad surface finishes (Thin Ni ENEPIG, OSP, ENEPIG, ENIG) were evaluated in terms of their interconnection reliability by thermal cycle (T/C) test up to 2000 cycles at temperatures ranging from -55°C to 125°C and high-temperature storage test up to 1000 h at 150°C. The contact resistances of the Cu pillar/Sn-Ag micro bump showed significant differences after the T/C reliability test in the following order: thin Ni ENEPIG > OSP > ENEPIG where the thin Ni ENEPIG pad metal finish provided the best Cu pillar/Sn-Ag micro bump interconnection in terms of bump joint reliability. Various IMCs formed between the bump joint areas can account for the main failure mechanism.

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

    Directory of Open Access Journals (Sweden)

    Pan Yi

    2017-02-01

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

  9. 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.

  10. 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。

  11. 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.

  12. 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...

  13. 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.

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

    Science.gov (United States)

    Fogarasi, Szabolcs; Imre-Lucaci, Florica; Egedy, Attila; Imre-Lucaci, Árpád; Ilea, Petru

    2015-06-01

    The present study aimed at developing an original and environmentally friendly process for the recovery of copper from waste printed circuit boards (WPCBs) by chemical dissolution with Fe(3+) combined with the simultaneous electrowinning of copper and oxidant regeneration. The recovery of copper was achieved in an original set-up consisting of a three chamber electrochemical reactor (ER) connected in series with a chemical reactor (CR) equipped with a perforated rotating drum. Several experiments were performed in order to identify the optimal flow rate for the dissolution of copper in the CR and to ensure the lowest energy consumption for copper electrodeposition in the ER. The optimal hydrodynamic conditions were provided at 400 mL/min, leading to the 75% dissolution of metals and to a low specific energy consumption of 1.59 kW h/kg Cu for the electrodeposition process. In most experiments, the copper content of the obtained cathodic deposits was over 99.9%.

  15. Research on Ultrafine Tungsten Carbide-Cobalt (WC-Co) Cemented Carbide Rods of Miniature Drills for Highly Integrated Printed Circuit Board (PCB)

    Institute of Scientific and Technical Information of China (English)

    Xiaoliang SHI; Gangqin SHAO; Xinglong DUAN; Runzhang YUAN

    2005-01-01

    Nanocrystalline tungsten carbide-cobalt (WC-Co) composite powders produced through spray thermal decomposition-continuous reduction and carburization technology were used to prepare φ3.25 mm ×38 mm ultrafine tungsten carbidecobalt (WC-Co) cemented carbide rods through vacuum sintering plus sinterhip technology. The microstructure,Vickers hardness, density and Rockwell A hardness (HRA), transverse rupture strength (TRS), saturated magnetization and coercivity force were tested. The results show that the average grain size of the sintering body prepared through vacuum sintering plus sinterhip technology was 430 nm; transverse rupture strength (TRS) was 3850 MPa;Vickers hardness was 1890 and Rockwell A hardness of sintering body was 93. High strength and high hardness ultrafine WC-Co cemented carbide rods used to manufacture printed circuit board (PCB) drills were obtained.

  16. 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

    2013-05-07

    Technologies could be integrated in different ways into automatic recycling lines for a certain kind of electronic waste according to practical requirements. In this study, a new kind of pneumatic separator with openings at the dust hooper was applied combing with electrostatic separation for recycling waste printed circuit boards. However, the flow pattern and the particles' movement behavior could not be obtained by experimental methods. To better control the separation quantity and the material size distribution, computational fluid dynamics was used to model the new pneumatic separator giving a detailed understanding of the mechanisms. Simulated results showed that the tangential velocity direction reversed with a relatively small value. Axial velocity exhibited two sharp decreases at the x axis. It is indicated that the bottom openings at the dust hopper resulted in an enormous change in the velocity profile. A new phenomenon that was named dusting was observed, which would mitigate the effect of particles with small diameter on the following electrostatic separation and avoid materials plugging caused by the waste printed circuit boards special properties effectively. The trapped materials were divided into seven grades. Experimental results showed that the mass fraction of grade 5, grade 6, and grade 7 materials were 27.54%, 15.23%, and 17.38%, respectively. Grade 1 particles' mass fraction was reduced by 80.30% compared with a traditional separator. Furthermore, the monocrystalline silicon content in silicon element in particles with a diameter of -0.091 mm was 18.9%, higher than that in the mixed materials. This study could serve as guidance for the future material flow control, automation control, waste recycling, and semiconductor storage medium destruction.

  17. Component-Level Electronic-Assembly Repair (CLEAR) Spacecraft Circuit Diagnostics by Analog and Complex Signature Analysis

    Science.gov (United States)

    Oeftering, Richard C.; Wade, Raymond P.; Izadnegahdar, Alain

    2011-01-01

    The Component-Level Electronic-Assembly Repair (CLEAR) project at the NASA Glenn Research Center is aimed at developing technologies that will enable space-flight crews to perform in situ component-level repair of electronics on Moon and Mars outposts, where there is no existing infrastructure for logistics spares. These technologies must provide effective repair capabilities yet meet the payload and operational constraints of space facilities. Effective repair depends on a diagnostic capability that is versatile but easy to use by crew members that have limited training in electronics. CLEAR studied two techniques that involve extensive precharacterization of "known good" circuits to produce graphical signatures that provide an easy-to-use comparison method to quickly identify faulty components. Analog Signature Analysis (ASA) allows relatively rapid diagnostics of complex electronics by technicians with limited experience. Because of frequency limits and the growing dependence on broadband technologies, ASA must be augmented with other capabilities. To meet this challenge while preserving ease of use, CLEAR proposed an alternative called Complex Signature Analysis (CSA). Tests of ASA and CSA were used to compare capabilities and to determine if the techniques provided an overlapping or complementary capability. The results showed that the methods are complementary.

  18. 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

    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...

  19. Impact of NaCl Contamination and Climatic Conditions on the Reliability of Printed Circuit Board Assemblies

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2014-01-01

    using single components (size 0805) and surface insulation resistance comb patterns precontaminated with sodium chloride at levels adjacent to levels used in the IPC J-STD-001 standard. The potential bias of 5–10 V was applied during experiments, and the climatic conditions were in the range 60%–98% RH...

  20. 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

  1. Effect of Microwave Printed Circuit Board Material on Pad%微波印制板材料对焊盘的影响

    Institute of Scientific and Technical Information of China (English)

    张朝东

    2016-01-01

    With the rapid miniaturization and integration of the microwave devices ,the requirements of the mi-crowave printed circuit board materials are increasingly high to meet the performance requirement of the de -vices.And many special microwave substrates have emerged ,such as the copper-based microstrip plate and the aluminum-based microstrip plate .Due to the environment and processing technology , many performance problems of these microwave substrates have appeared in the application .In this paper the fault location and reason analysis of the channel failure in the environmental test are analyzed .The defects of copper-based mi-crowave printed circuit board materials are identified from the pad hole by test and processing analysis .The defect reason is analyzed and new materials are used to solve the problem .%随着微波器件微型化和集成化的快速发展,微波器件对微波印制板材料的要求越来越高以满足其性能指标,出现了许多特殊的微波基材,如铜基微带板和铝基微带板。这些微波板材的制造工艺技术较高,在实际使用中受环境因素和加工技术的影响,出现了许多性能问题。文中针对环境试验中出现的模块通道故障进行故障定位和原因分析,通过工艺试验和工艺分析,从焊盘过孔中查找出铜基微波印制板材料的缺陷,对引起材料缺陷的原因进行了分析,并采用新材料排除了故障。

  2. 基于故障物理的电路板可靠性分析%Reliability Analysis of Circuit Board Based on Physics of Failure

    Institute of Scientific and Technical Information of China (English)

    王文; 范源远; 王成刚; 胡建明; 黄胜利

    2013-01-01

    在装备生命周期的各阶段,其承受的环境载荷都可能对装备造成累积损伤,进而引发故障。从装备设计特性和寿命期环境应力分布及其相互作用角度来分析装备的故障更符合其未来实际使用情况。介绍了电路板常用的故障物理模型,阐述了基于故障物理的电路板可靠性分析流程,明确了潜在故障仿真思路,为装备早期可靠性设计、测试性设计与评价提供了方法依据。%At every stage of life cycle, environmental loads may cause cumulative damage to the equipment, and then caus-ing fault. It is in accord with the actual usage in the future for equipment to analyze its faults from the angle of the design feature of equipments, longevity environment stress distribution and the interaction between them. The common fault physi-cal models of circuit boards were presented, and the circuit reliability analysis process based on physics-of-failure (PoF) was expounded. The simulation method of potential fault was expatiated. A feasible method was provided for the early eval-uation and design for reliability and testability of equipment.

  3. 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。

  4. 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。

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

    Science.gov (United States)

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

    2016-09-01

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

  6. 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.

  7. 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℃。

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

    Science.gov (United States)

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

    2016-04-01

    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.

  9. The major components of particles emitted during recycling of waste printed circuit boards in a typical e-waste workshop of South China

    Science.gov (United States)

    Bi, Xinhui; Simoneit, Bernd R. T.; Wang, ZhenZhen; Wang, Xinming; Sheng, Guoying; Fu, Jiamo

    2010-11-01

    Electronic waste from across the world is dismantled and disposed of in China. The low-tech recycling methods have caused severe air pollution. Air particle samples from a typical workshop of South China engaged in recycling waste printed circuit boards have been analyzed with respect to chemical constituents. This is the first report on the chemical composition of particulate matter (PM) emitted in an e-waste recycling workshop of South China. The results show that the composition of PM from this recycling process was totally different from other emission sources. Organic matter comprised 46.7-51.6% of the PM. The major organic constituents were organophosphates consisting mainly of triphenyl phosphate (TPP) and its methyl substituted compounds, methyl esters of hexadecanoic and octadecanoic acids, levoglucosan and bisphenol A. TPP and bisphenol A were present at 1-5 orders of magnitude higher than in other indoor and outdoor environments throughout the world, which implies that they might be used as potential markers for e-waste recycling. The elemental carbon, inorganic elements and ions had a minor contribution to the PM (waste recycling locale.

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

    Science.gov (United States)

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

    2012-11-15

    Recovery of valuable materials from waste printed circuit boards (WPCBs) is quite difficult because WPCBs is a heterogeneous mixture of polymer materials, glass fibers, and metals. In this study, WPCBs was treated using ionic liquid (1-ethyl-3-methylimizadolium tetrafluoroborate [EMIM+][BF4-]). Experimental results showed that the separation of the solders went to completion, and electronic components (ECs) were removed in WPCBs when [EMIM+][BF4-] solution containing WPCBs was heated to 240 °C. Meanwhile, metallographic observations verified that the WPCBs had an initial delamination. When the temperature increased to 260 °C, the separation of the WPCBs went to completion, and coppers and glass fibers were obtained. The used [EMIM+][BF4-] was treated by water to generate a solid-liquid suspension, which was separated completely to obtain solid residues by filtration. Thermal analyses combined with infrared ray spectra (IR) observed that the solid residues were bromine epoxy resins. NMR (nuclear magnetic resonance) showed that hydrogen bond played an important role for [EMIM+][BF4-] dissolving bromine epoxy resins. This clean and non-polluting technology offers a new way to recycle valuable materials from WPCBs and prevent environmental pollution from WPCBs effectively.

  11. 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。

  12. 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.

  13. 基于虚拟仪器的雷达电路板自动测试系统%Design and Realization of Radar Circuit Board Automated Test System Based on Virtual Instrument

    Institute of Scientific and Technical Information of China (English)

    郭甲阵; 谢华; 兰京川

    2011-01-01

    In order to solve the unicity and specificity faults of traditional circuit board test system and to meet the automatic testing demand of different circuit boards,a radar circuit board automated test system based on virtual instrument and signal-oriented automatic test technology was investigated and designed. The universal system hardware platform was designed based on PXIbus and the software platform comsists of a TPS development system and a TPS runtime system. The system implements visual edition of test strategy and visual test procedure and the automation of diagnostic test and can produce test report automatically.%为了解决传统电路板测试系统的单一性和专用性缺点,满足不同电路板的自动测试需求,基于虚拟仪器技术和面向信号的自动测试技术,设计并实现了一种雷达电路板自动测试系统.该系统基于PXI总线技术构建通用的硬件测试框架,软件平台采用TPS开发和运行相分离的形式,实现了测试策略及测试流程的可视化编辑,以及测试诊断的自动化和测试报告的自动生成.

  14. Advanced degradation of brominated epoxy resin and simultaneous transformation of glass fiber from waste printed circuit boards by improved supercritical water oxidation processes.

    Science.gov (United States)

    Liu, Kang; Zhang, Zhiyuan; Zhang, Fu-Shen

    2016-10-01

    This work investigated various supercritical water oxidation (SCWO) systems, i.e. SCWO1 (only water), SCWO2 (water+H2O2) and SCWO3 (water+H2O2/NaOH), for waste printed circuit boards (PCBs) detoxification and recycling. Response surface methodology (RSM) was applied to optimize the operating conditions of the optimal SCWO3 systems. The optimal reaction conditions for debromination were found to be the NaOH of 0.21g, the H2O2 volume of 9.04mL, the time of 39.7min, maximum debromination efficiency of 95.14%. Variance analysis indicated that the factors influencing debromination efficiency was in the sequence of NaOH>H2O2>time. Mechanism studies indicated that the dissociated ions from NaOH in supercritical water promoted the debromination of brominated epoxy resins (BERs) through an elimination reaction and nucleophilic substitution. HO2, produced by H2O2 could induce the oxidation of phenol ring to open (intermediates of BERs), which were thoroughly degraded to form hydrocarbons, CO2, H2O and NaBr. In addition, the alkali-silica reaction between OH(-) and SiO2 induced the phase transformation of glass fibers, which were simultaneously converted into anorthite and albite. Waste PCBs in H2O2/NaOH improved SCWO system were fully degraded into useful products and simultaneously transformed into functional materials. These findings are helpful for efficient recycling of waste PCBs.

  15. 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.

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

    Science.gov (United States)

    Xiu, Fu-Rong; Qi, Yingying; Zhang, Fu-Shen

    2015-07-01

    Precious metals are the most attractive resources in waste printed circuit boards (PCBs) of mobile phones. In this work, an alternative process for recovering Au, Ag, and Pd from waste PCBs of mobile phones by supercritical water oxidation (SCWO) pre-treatment combined with iodine-iodide leaching process was developed. In the process, the waste PCBs of mobile phones were pre-treated in supercritical water, then a diluted hydrochloric acid leaching (HL) process was used to recovery the Cu, whose leaching efficiency was approximately 100%, finally the resulting residue was subjected to the iodine-iodide leaching process for recovering the Au, Ag, and Pd. Experimental results indicated that SCWO pre-treatment temperature, time, and pressure had significant influence on the Au, Ag, and Pd leaching from (SCWO+HL)-treated waste PCBs. The optimal SCWO pre-treatment conditions were 420°C and 60min for Au and Pd, and 410°C and 30min for Ag. The optimum dissolution parameters for Au, Pd, and Ag in (SCWO+HL)-treated PCBs with iodine-iodide system were leaching time of 120min (90min for Ag), iodine/iodide mole ratio of 1:5 (1:6 for Ag), solid-to-liquid ratio (S/L) of 1:10g/mL (1:8g/mL for Ag), and pH of 9, respectively. It is believed that the process developed in this study is environment friendly for the recovery of Au, Ag, and Pd from waste PCBs of mobile phones by SCWO pre-treatment combined with iodine-iodide leaching process.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, P., E-mail: xhnzp@shu.edu.cn [Key Laboratory of Solid Waste Treatment and Resource Recycle (SWUST), Ministry of Education and College of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444 (China); Chen, Y.; Wang, L.Y.; Qian, G.Y. [Key Laboratory of Solid Waste Treatment and Resource Recycle (SWUST), Ministry of Education and College of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444 (China); Zhou, M. [Semiconductor Manufacturing International (Shanghai) Corporation, 18 Zhangjiang Road, Shanghai 201203 (China); Zhou, J. [Institute of Microelectronics, Peking University, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer WPCBs were heated in [EMIM{sup +}][BF{sub 4}{sup -}] for recovering solider at 240 Degree-Sign C. Black-Right-Pointing-Pointer The bromine epoxy resins in WPCBs were all dissolved in [EMIM{sup +}][BF{sub 4}{sup -}] at 260 Degree-Sign C. Black-Right-Pointing-Pointer Used [EMIM{sup +}][BF{sub 4}{sup -}] 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{sup +}][BF{sub 4}{sup -}]). Experimental results showed that the separation of the solders went to completion, and electronic components (ECs) were removed in WPCBs when [EMIM{sup +}][BF{sub 4}{sup -}] solution containing WPCBs was heated to 240 Degree-Sign C. Meanwhile, metallographic observations verified that the WPCBs had an initial delamination. When the temperature increased to 260 Degree-Sign C, the separation of the WPCBs went to completion, and coppers and glass fibers were obtained. The used [EMIM{sup +}][BF{sub 4}{sup -}] 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{sup +}][BF{sub 4}{sup -}] 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.

  18. 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

  19. 立体组装电路模块动态特性的有限元模拟与分析%Simulation and Analysis of Dynamic Characteristics of 3D Assembly Circuit Module with Finite Element Method

    Institute of Scientific and Technical Information of China (English)

    黄春跃; 周德俭; 黄红艳

    2004-01-01

    Based on the modal analysis theory and by using the dynamics finite element analysis model of a three-dimensional assembly circuit module, dynamic characteristics of circuit module have been studied, including both natural characteristics analysis and dynamic responses analysis. Using a subspace method, modal analysis is first carried out. The first 6 orders of natural frequencies and vibration modes are obtained. Influence of the number of the Z-shaped metal slices on dynamic characteristics of the entire structure is also studied.Harmonic response analysis is then conducted. The steady-state response when the circuit module is subjected to harmonic excitation is determined. A curve of the response values against frequencies is obtained. As a result, the optimal number of Z-shaped metal slices can be determined, and it can be assured that the three-dimensional assembly circuit module has good performance in terms of the dynamic characteristics.

  20. Process development for recovery of copper and precious metals from waste printed circuit boards with emphasize on palladium and gold leaching and precipitation.

    Science.gov (United States)

    Behnamfard, Ali; Salarirad, Mohammad Mehdi; Veglio, Francesco

    2013-11-01

    A novel hydrometallurgical process was proposed for selective recovery of Cu, Ag, Au and Pd from waste printed circuit boards (PCBs). More than 99% of copper content was dissolved by using two consecutive sulfuric acid leaching steps in the presence of H2O2 as oxidizing agents. The solid residue of 2nd leaching step was treated by acidic thiourea in the presence of ferric iron as oxidizing agent and 85.76% Au and 71.36% Ag dissolution was achieved. The precipitation of Au and Ag from acidic thiourea leachate was investigated by using different amounts of sodium borohydride (SBH) as a reducing agent. The leaching of Pd and remained gold from the solid reside of 3rd leaching step was performed in NaClO-HCl-H2O2 leaching system and the effect of different parameters was investigated. The leaching of Pd and specially Au increased by increasing the NaClO concentration up to 10V% and any further increasing the NaClO concentration has a negligible effect. The leaching of Pd and Au increased by increasing the HCl concentration from 2.5 to 5M. The leaching of Pd and Au were endothermic and raising the temperature had a positive effect on leaching efficiency. The kinetics of Pd leaching was quite fast and after 30min complete leaching of Pd was achieved, while the leaching of Au need a longer contact time. The best conditions for leaching of Pd and Au in NaClO-HCl-H2O2 leaching system were determined to be 5M HCl, 1V% H2O2, 10V% NaClO at 336K for 3h with a solid/liquid ratio of 1/10. 100% of Pd and Au of what was in the chloride leachate were precipitated by using 2g/L SBH. Finally, a process flow sheet for the recovery of Cu, Ag, Au and Pd from PCB was proposed.

  1. 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.

  2. 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.

  3. 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。

  4. 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...

  5. Self-assembled monolayer of designed and synthesized triazinedithiolsilane molecule as interfacial adhesion enhancer for integrated circuit

    Directory of Open Access Journals (Sweden)

    Wang Fang

    2011-01-01

    Full Text Available Abstract Self-assembled monolayer (SAM with tunable surface chemistry and smooth surface provides an approach to adhesion improvement and suppressing deleterious chemical interactions. Here, we demonstrate the SAM comprising of designed and synthesized 6-(3-triethoxysilylpropylamino-1,3,5-triazine-2,4-dithiol molecule, which can enhance interfacial adhesion to inhibit copper diffusion used in device metallization. The formation of the triazinedithiolsilane SAM is confirmed by X-ray photoelectron spectroscopy. The adhesion strength between SAM-coated substrate and electroless deposition copper film was up to 13.8 MPa. The design strategy of triazinedithiolsilane molecule is expected to open up the possibilities for replacing traditional organosilane to be applied in microelectronic industry.

  6. Self-assembled monolayer of designed and synthesized triazinedithiolsilane molecule as interfacial adhesion enhancer for integrated circuit.

    Science.gov (United States)

    Wang, Fang; Li, Yanni; Wang, Yabin; Cao, Zhuo

    2011-08-03

    Self-assembled monolayer (SAM) with tunable surface chemistry and smooth surface provides an approach to adhesion improvement and suppressing deleterious chemical interactions. Here, we demonstrate the SAM comprising of designed and synthesized 6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-dithiol molecule, which can enhance interfacial adhesion to inhibit copper diffusion used in device metallization. The formation of the triazinedithiolsilane SAM is confirmed by X-ray photoelectron spectroscopy. The adhesion strength between SAM-coated substrate and electroless deposition copper film was up to 13.8 MPa. The design strategy of triazinedithiolsilane molecule is expected to open up the possibilities for replacing traditional organosilane to be applied in microelectronic industry.

  7. Self-assembled monolayer of designed and synthesized triazinedithiolsilane molecule as interfacial adhesion enhancer for integrated circuit

    Science.gov (United States)

    2011-01-01

    Self-assembled monolayer (SAM) with tunable surface chemistry and smooth surface provides an approach to adhesion improvement and suppressing deleterious chemical interactions. Here, we demonstrate the SAM comprising of designed and synthesized 6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-dithiol molecule, which can enhance interfacial adhesion to inhibit copper diffusion used in device metallization. The formation of the triazinedithiolsilane SAM is confirmed by X-ray photoelectron spectroscopy. The adhesion strength between SAM-coated substrate and electroless deposition copper film was up to 13.8 MPa. The design strategy of triazinedithiolsilane molecule is expected to open up the possibilities for replacing traditional organosilane to be applied in microelectronic industry. PMID:21812994

  8. 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.

  9. Biochemical Leaching-Extraction-Electrodeposition Technology for Recovery of Copper from Wasted Printed Circuit Board%生化浸出—萃取—电积提取废弃线路板中铜

    Institute of Scientific and Technical Information of China (English)

    周吉奎; 胡洁

    2012-01-01

    Taking improving 9K culture solution inoculated from Thiobacillus ferrooxidans (calling "GZY - 1#" ) as the leaching agent, N902 as the extraction agent, the sulfuric acid solution as a stripping agent, and the lead-based alloy plates and stainless steel plates as the anode and cathode of the electrolyzerat respectively, experiments of biochemical leac-hing-extraction-electrodeposition are made to extract copper from waste printed circuit boards of Guangdong Qingyuan Jintian Nonferrous Metals Company at room temperature. Under the appropriate conditions, the average copper leaching rate from samples reached 95. 29% , and the average copper content in leached residue reduced by 0. 088%. Through the extract-back-extract-electrodeposition, the electrodeposited copper purity reached 99. 95% . Through the tests, high recovery of copper from waste printed circuit boards was realized, and the problem of the copper interference in comprehensive utilization of non-metallic materials in the waste printed circuit board was solved as well.%以接种代号为GZY-1#的氧化亚铁硫杆菌的改进9K培养液为浸出剂、N902为萃取剂、硫酸溶液为反萃剂、铅基合金板和不锈钢板分别为电解槽的阳极和阴极,在室温下对广东清远进田有色金属公司废弃线路板重选尾渣中的铜进行了生化浸出-萃取-电积试验.在选定的合适条件下,试样中铜的平均浸出率达到95.29%,浸渣平均铜含量降至0.088%;浸出液经萃取-反萃取-电积,获得了纯度达到99.95%的电积铜.试验不仅使废弃线路板重选尾渣中的铜得到了高效回收,还解决了铜对废弃线路板重选尾渣中非金属材料综合利用的干扰问题.

  10. ased on the SMT technology pad of printed circuit board design%基于表面贴装工艺技术的印制板焊盘设计

    Institute of Scientific and Technical Information of China (English)

    张建碧

    2012-01-01

    伴随表面贴装技术的广泛运用,印刷电路板设计工艺变得越来越重要,焊盘设计要求也变得越来越高。本文针对焊盘设计存在的缺陷加以归纳并给出了较详细的改进措施。%With surface mount technology extensive use, printed circuit board design process becomes more and more important, welding plate design requirements also becomes more and more high. This article in view of the defects of welding plate design summarized and gives a detailed measures for improvement.

  11. 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

  12. Effect of Microwave Printed Circuit Board Material on Pad%微波印制板材料对焊盘的影响

    Institute of Scientific and Technical Information of China (English)

    张朝东

    2016-01-01

    随着微波器件的微型化和集成化的快速发展,为了满足性能指标,对微波印制板材料的要求也越来越高,出现了许多特殊的微波基材,如铜基微带板和铝基微带板。由于这些微波板材的制造工艺技术较高,在实际使用中受环境因素和加工技术的影响,出现了许多性能问题。针对环境试验中模块出现的通道故障进行故障定位和原因分析,通过工艺试验和工艺分析的方法,从焊盘过孔中查找出铜基微波印制板材料的缺陷问题,对引起材料缺陷的原因进行了分析,并采用新材料解决故障。%With the rapid development of microwave device for miniaturization and integration, the requirements of microwave printed board material Is becoming increasingly higher, in order to meet the performance index. There have been many special microwave substrates, such as microstrip board based copper or aluminum. Due to the influence of environmental factors and processing technology, many performance problems have appeared in the practical application. the fault location and reason analysis of the channel failure in the environmental test are analyzed. The copper based microwave printed board material defects were found in via on pad by analyzing the process test and method. Analyses the reason of material defects, and new materials are used to solve the problem.

  13. Modeling and Simulation of the RS422 Interface Circuit on Board Satellite%星上RS422接口电路的建模与仿真

    Institute of Scientific and Technical Information of China (English)

    李新贝; 谭超; 高山; 邵根忠

    2011-01-01

    Based on the worst case analysis and the superposition theorem, the equivalent model is set up for RS422 interface circuit. By using the node voltage method, the electric potential of the differential input signal is calculated, and the relation curves between the signal and the bias resistance are simulated with the help of Matlab 7. 0. 1 software. Finally, its bias resistance value range is given, and the best value is drawn according to the experiments and the circuit theory.%基于最坏情况分析法结合叠加定理对星上RS422串行总线通信技术接口电路建立了等效电路模型,并结合节点电压法计算出了最坏情况下接收器输入端差分信号的电位,运用Matlab 7.0.1软件绘制出了该信号与偏置电阻之间的关系曲线,确定了偏王电阻阻值的选取范围,结合试验和工程实践给出了偏置电阻的最佳取值,保证了通信的可靠性.

  14. Integrated capacitors for conductive lithographic film circuits

    OpenAIRE

    Harrey, PM; Evans, PSA; Harrison, DJ

    2001-01-01

    This paper reports on fabrication of low-value embedded capacitors in conductive lithographic film (CLF) circuit boards. The CLF process is a low-cost and high speed manufacturing technique for flexible circuits and systems. We report on the construction and electrical characteristics of CLF capacitor structures printed onto flexible substrates. These components comprise a single polyester dielectric layer, which separates the printed electrode films. Multilayer circuit boards with printed co...

  15. Stiffener lamination defect improvement of Flexible Printed Circuit Boards%挠性板压合补强缺陷改善

    Institute of Scientific and Technical Information of China (English)

    莫欣满; 徐波; 陈蓓

    2012-01-01

    Stiffener lamination of FPC to strengthen support flexible substrates is always one of the vital steps in FPC producing process. Stiffener lamination requires the use of thermosetting adhesive as bonding. Due to the existence of the gap between the circuit substrate and the flexible plate, the difficult problem of AD underfilling always exist in the lamination process, adhesive filling full or not directly affect the product reliability and durability. By studying the resin filling difficulties in different circuit layout, a simple relationship based on a series of line spacing under different copper thickness was given through resin filling requirement and CVL bending depth, the selection principle of the thickness of the stiffener adhesive. Also different conforming type way were contrast, filling voids and pad depression made to analysis to improve, the better improve way was given by not change the lamination parameters.%挠性板生产过程中,在板上局部位置压合补强板以加强对挠性基板的支撑和方便插接是关键流程之一。补强热压时一般是采用半固化态且流动性相对较小的热固性等胶作为粘结,且由于一些补强板刚性大变形小,因此补强的压合过程存在填胶难的问题,胶的填充饱满与否直接影响到产品的可靠性和耐用性。通过研究不同的线路布置时填胶的难易,根据不同铜厚下的系列线路间距所需填胶量与覆盖膜弯曲深度的简单关系,提出了补强压合胶厚的选择原则;同时通过覆型方式的对比,对填胶空洞和焊盘凹陷等做出改善分析,在不改变压合参数的前提下给出了可行的改善途径。

  16. 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.

  17. 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.

  18. 硫脲法从废旧电路板中浸取金、银的研究%Experimental Study of Thiourea Leaching Gold and Silver from Waste Circuit Boards

    Institute of Scientific and Technical Information of China (English)

    徐秀丽; 李晶莹

    2011-01-01

    废旧电路板中含有丰富的可回收金属Cu,Au,Ag,Pt,Pb等,其处理处置、无害化、资源化成为经济发展中急需解决的问题.采用硫脲法对废旧电路板中的金、银进行浸取实验,主要考察了反应时间、反应温度、硫脲浓度、Fe3+的质量浓度、物料粒度对金及银浸出率的影响.结果表明,在最佳浸取条件下,金、银都能达到理想的浸取效果,金和银的最高浸取率分别达到90.87%和59.82%.硫脲提金法因溶金速度快,浸出时低毒、价格低廉、高效、有利于环保、干扰离子少等优点而成为取代氰化提金的绿色浸金方法.%Waste circuit boards contain a rich resource of recoverable metals such as Cu, Au, Ag, Pt, and Pb. Its disposal, harmless and recycling have become the key problems solved urgently with the economic development. Thiourea leaching gold and silver from the waste circuit board was carried out, and the influence of leaching time, react temperature, thiourea concentration, Fe3+concentration and material particle size on gold leaching rates were investigated. The results showed that, Gold and silver leaching rates can reach the best results under the best canditions, and the highest leaching rates of gold and silver were 90.87% and 59. 82%, respectively. Thiourea leaching gold has the advantages of quick leaching speed, low-toxic, low-cost, high efficiency, environmental friendly, less interference ions, and it is becoming green leaching gold method to replace cyanide leaching gold.

  19. 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.

  20. Clock Circuit Analysis of DX200 Medium Wave Transmitter's Control Board%DX200中波发射机控制板卡时钟电路解析

    Institute of Scientific and Technical Information of China (English)

    余芳

    2016-01-01

    DX200 medium wave transmitter's control board has a stepping sequence control function when the transmitter starts. Also it monitors the power amplifier unit and gives protective response to the faults of internal and external parts, etc. In order to make every control circuit coordinately work on time, we have adopted a 555 in-tegrated timer which constitutes an astable free-running multivibrator with peripheral resistance and capacitance. The multivibrator generates an 8 KHZ clock signal. Frequency divider made with 74 hc161 synchronous counting units produces 4 KHZ, 128 HZ, 64 HZ, 16 HZ and 1/64 HZ, sends them to each PAL and programmable logic de-vices, and then provides corresponding control. Based on 555 integrated timer and 74 hc161 synchronous counter, the paper introduces in detail the structure and internal principle and their functions, and elaborates the generating principle of the transmitter control board's clock circuit.%DX200中波发射机控制板为发射机提供开机时步进起动的顺序控制,还对功放单元进行监视,对内部外部的故障情况进行保护性响应等,为了使各个部分控制电路在时间上能够协调的工作,我们采用一只555集成定时器与外围电阻、电容构成一个无稳态自激多谐振荡器,使其产生8KHZ的时钟信号。利用74HC161同步计数机组成分频器产生的4kHz,128Hz,64Hz,16Hz,1/64Hz发送到每个PAL和可编程逻辑器件,提供相应的控制。本文详细介绍了555集成定时器和74HC161同步计数器的结构组成、内部原理及其功能,阐述了发射机控制板卡时钟电路产生的原理。

  1. 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%.

  2. 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...

  3. 线路板废弃污泥资源化无害化处理新工艺%New Technology for Resource Utilization and Harmless Treatment of the Printed Circuit Board Waste Sludge

    Institute of Scientific and Technical Information of China (English)

    谢逢春; 李海英; 温旭辉

    2009-01-01

    阐述了广东省惠州市惠州大亚湾惠绿环保服务有限公司开发的一套完整的线路板厂废弃污泥资源化、无害化的处理工艺,这套工艺采用酸浸和氨浸相结合的方法,成功的解决了主金属和其他金属有效分离这一关键技术难题,克服了原有工艺的缺陷,达到了理想的分离效果,具有处理成本低、处理量大、回收率高、产品质量好、没有二次污染等特点.%This paper depicts a technique for resource utilization and harmless treatment of the printed circuit board waste sludge which had been successfully applied to a metal recovery plant in city of Huizhou. This process resolved problem about how to separate the main metal from other metals successfully with combines acid leaching with ammonia leaching, and overcame the defects in the tech-nique before. The results show that this new technique has excellent effect with low cost, large quantity, high recovery ratio, no sec-ondary pollution and good product quality.

  4. 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.

  5. Genetic circuit design automation.

    Science.gov (United States)

    Nielsen, Alec A K; Der, Bryan S; Shin, Jonghyeon; Vaidyanathan, Prashant; Paralanov, Vanya; Strychalski, Elizabeth A; Ross, David; Densmore, Douglas; Voigt, Christopher A

    2016-04-01

    Computation can be performed in living cells by DNA-encoded circuits that process sensory information and control biological functions. Their construction is time-intensive, requiring manual part assembly and balancing of regulator expression. We describe a design environment, Cello, in which a user writes Verilog code that is automatically transformed into a DNA sequence. Algorithms build a circuit diagram, assign and connect gates, and simulate performance. Reliable circuit design requires the insulation of gates from genetic context, so that they function identically when used in different circuits. We used Cello to design 60 circuits forEscherichia coli(880,000 base pairs of DNA), for which each DNA sequence was built as predicted by the software with no additional tuning. Of these, 45 circuits performed correctly in every output state (up to 10 regulators and 55 parts), and across all circuits 92% of the output states functioned as predicted. Design automation simplifies the incorporation of genetic circuits into biotechnology projects that require decision-making, control, sensing, or spatial organization.

  6. Algebraic circuits

    CERN Document Server

    Lloris Ruiz, Antonio; Parrilla Roure, Luis; García Ríos, Antonio

    2014-01-01

    This book presents a complete and accurate study of algebraic circuits, digital circuits whose performance can be associated with any algebraic structure. The authors distinguish between basic algebraic circuits, such as Linear Feedback Shift Registers (LFSRs) and cellular automata, and algebraic circuits, such as finite fields or Galois fields. The book includes a comprehensive review of representation systems, of arithmetic circuits implementing basic and more complex operations, and of the residue number systems (RNS). It presents a study of basic algebraic circuits such as LFSRs and cellular automata as well as a study of circuits related to Galois fields, including two real cryptographic applications of Galois fields.

  7. 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

  8. 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

  9. EFFECT OF MOLD ON CORROSION BEHAVIOR OF PRINTED CIRCUIT BOARD-COPPER AND ENIG FINISHED%霉菌对裸铜和镀金处理的印制电路板腐蚀行为的影响

    Institute of Scientific and Technical Information of China (English)

    邹士文; 李晓刚; 董超芳; 李慧艳; 肖葵

    2012-01-01

    With the development of miniaturization of electronic circuits and occurrence of growing number of project failure cases, the corrosion behavior of printed circuit board (PCB) becomes a non-ignorable scientific issue under the hygrothermal condition with mold. In this paper, the corrosion behavior of unfinished PCB (PCB-Cu) and PCB finished by electroless nickel immersion gold (PCB-ENIG) in mold environment was studied using scanning Kelvin probe (SKP). The mold growth behavior was observed by stereo microscope and SEM, and the corrosion products were analyzed by EDS. The results showed that the number of mold increased on the surface of PCB-Cu and PCB-ENIG specimens under hygrothermal condition. After a growth cycle of 28 d, the new generation of conidium formed with good activity. After 84 d mold test, corrosion occurred on both two kinds of specimens and it was more severe on PCB-ENIG. Meanwhile the activity of mold was an inhibitor in the corrosion process of PCB-Cu and a promoter in the pore corrosion process of PCB ENIG.%采用扫描Kelvin探针测试技术研究了裸铜印制电路板(PCB-Cu)和无电镀镍金处理印制电路板(PCB-ENIG)在霉菌作用下的腐蚀行为,通过体视学显微镜、扫描电镜和能谱分析对PCB的腐蚀和霉菌生长情况进行了观察和分析.结果表明,在湿热环境下霉菌在2种材料表面均能良好生长并且数量逐渐增加,28d完成一个生长代谢周期且分生孢子活性良好;84d后试样表面都出现了腐蚀产物,PCB-ENIG腐蚀更为严重.霉菌的生长代谢作用在一定程度上能抑制PCB-Cu表面霉菌生长区域的腐蚀,但是对PCB-ENIG的微孔腐蚀起促进作用.

  10. 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。

  11. 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.

  12. 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.

  13. Integrated cooling concepts for printed circuit boards

    NARCIS (Netherlands)

    Wits, Wessel Willems

    2008-01-01

    Thermal management plays an increasingly dominant role in the design process of electronic products. Component sizes decrease while performance and functional demands increase, resulting in more power dissipation on smaller surfaces. In an effort to cope with these growing thermal challenges, indust

  14. Printed circuit board designer's reference basics

    CERN Document Server

    Robertson, Chris

    2003-01-01

    PCB design instruction and reference manual, all in one book, with in- depth explanation of the processes and tools used in modern PCB design Standards, formulas, definitions, and procedures, plus software to tie it all together.

  15. Assembly Manual for the Berkeley Lab Cosmic Ray Detector

    CERN Document Server

    Collier, M

    2002-01-01

    The Berkeley Lab Cosmic Ray Detector consists of 3 main components that must be prepared separately before they can be assembled. These components are the scintillator, circuit board, and casing. They are described in the main sections of this report, which may be completed in any order. Preparing the scintillator paddles involves several steps--cutting the scintillator material to the appropriate size and shape, preparing and attaching Lucite cookies (optional), polishing the edges, gluing the end to the photomultiplier tube (optional), and wrapping the scintillator. Since the detector has 2 paddles, each of the sections needs to be repeated for the other paddle.

  16. Assembly Manual for the Berkeley Lab Cosmic Ray Detector

    Energy Technology Data Exchange (ETDEWEB)

    Collier, Michael

    2002-12-17

    The Berkeley Lab Cosmic Ray Detector consists of 3 main components that must be prepared separately before they can be assembled. These components are the scintillator, circuit board, and casing. They are described in the main sections of this report, which may be completed in any order. Preparing the scintillator paddles involves several steps--cutting the scintillator material to the appropriate size and shape, preparing and attaching Lucite cookies (optional), polishing the edges, gluing the end to the photomultiplier tube (optional), and wrapping the scintillator. Since the detector has 2 paddles, each of the sections needs to be repeated for the other paddle.

  17. 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.

  18. Design of Microstrip Vertical Transition in Multilayered Printed Circuit Board for Ultra Wide-band Communication%一种适用于超宽带通信的微带垂直转换结构

    Institute of Scientific and Technical Information of China (English)

    申振宁; 庄奕琪; 曾志斌

    2012-01-01

    A new microstrip vertical transition based on the via in multilayered printed circuit board is proposed for Ultra Wide-Band (UWB) communication. The planar electromagnetic band-gap unit is etched on power plane around the vias to suppress resonance and reduce self impedance of the Power Distribution Network (PDN), and then transmission performance is improved. The interconnect structure is decoupled into microstrip mode and power ground pair mode which coupled in the vias. The network analysis method is used to estimate system performance efficiently. The simulated and measured results show that the proposed transition has an insertion loss of <0.4 dB across the frequency band 3.1-10.6 GHz. By comparison with the method of adding shorting vias between PDN, the proposed structure in this paper benefits of low cost for one less routing layer with considerable performance.%该文提出一种适用于超宽带电路的基于过孔的微带垂直转换结构.通过在过孔附近的电源层上蚀刻平面电磁带隙单元来抑制电源分配网络谐振,降低其在过孔处的自阻抗,以改善垂直互连结构传输性能.将互连结构分解为过孔处耦合的微带线结构和电源平面对结构,并使用网络分析方法快速估算系统传输性能.仿真和实验测试表明在3.1-10.6 GHz的超宽带频段内过孔的插入损耗小于0.4 dB.与在电源分配网络之间添加短路过孔方法相比,该结构在传输性能相当的前提下减少了一个布线层,从而降低了设备成本.

  19. 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.

  20. 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.

  1. Research of On-Board Optical Switching Assembly Algorithm Based on Mixed Threshold and Round-Robin Scheme%基于Round-Robin方法的星载光交换混合门限组装算法研究

    Institute of Scientific and Technical Information of China (English)

    李瑞欣; 赵尚弘; 李勇军; 张晓燕; 康巧燕

    2013-01-01

    根据卫星光交换网络的高带宽、低丢包率和高链路利用率应用需求,结合现有的地面光交换组装算法,提出了一种新的基于混合门限和轮询方式的星载光交换组装算法.算法首先按照优先级缓存分组,再按照混合门限和轮询方式组装IP分组,减少突发数据包的空闲率,提高了链路利用率.理论分析与仿真证明该算法计算复杂度与轮询方式相同,突发数据包空闲率低于10_4,丢包率在负载为0.5时平均达到10-6,适用于星载光交换系统.%According to the high bandwidth, low packet-loss ratio, high channel utility requirements of satellite optical switching network, an on-board assembly algorithm based on mixed threshold and round-robin scheme is proposed combining the ground optical assembly algorithm. The algorithm caches the IP packet according to the parity, and assembles the packet according to the mixed threshold and round-robin scheme. Through the scheme, the padding ratio of burst is lowered. From the results of analysis and emulation, it is found that the complexity is the same as that of the round-robin method; the padding ratio of burst data packer is less than 10~4 when the load is 0.65, and the packet loss rate is 10-6 when the load is 0. 5. This algorithm meets the requirements of optical satellite communications.

  2. Circuit Design of Spectrometry Logging Tool with Modular Assembly%模块化能谱测井仪电路设计

    Institute of Scientific and Technical Information of China (English)

    张智; 韩冬

    2001-01-01

    根据各种能谱测井仪器的共同特点,应用比较先进的电子学技术,可以设计出满足大多数能谱测井仪应用要求的电路模块。然后用这些模块按需组合成不同的能谱测井仪器,这样就不仅可以实现一机多用,而且对于设备的调度、维修及未来的升级都十分有利。%According to the common characteristic of various spectral logging tools,a kind of circuit module can be obtained with new electronics techniques for designig several new spectral logging tools.These circuit modules can be used and changed independently.Then the new logging tools can be easily debugged,repaired and upgraded.

  3. 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)

  4. 微波马弗炉处理—火焰原子吸收光谱法测定废旧电路板中金银铂钯%Determination of gold, silver, platinum, palladium in waste circuit boards samples by flame atomic absorption spectrometry with microwave muffle furnace pretreatment

    Institute of Scientific and Technical Information of China (English)

    叶艳青; 羊波; 杨新周; 李银科; 胡秋芬

    2012-01-01

    A novel method for the determination of gold, silver, platinum and palladium in waste circuit board samples was investigated in this paper by flame atomic absorption spectrometry with microwave muffle furnace pretreatment. 5. 0 g of crashed waste circuit board samples was weighed and burned in microwave muffle furnace at 550 ℃ for 30 min to decompose organic matter. After the burning things were dissolved with aqua regia, gold, silver, platinum and palladium in the sample solution were determined by flame atomic absorption spectrometry. The detection limit of gold, silver, platinum and palladium was 0. 078, 0. 12, 0. 15 and 0. 15 mg/mL, respectively. The recoveries were between 90% and 108%. The method was applied to the same waste circuit board sample for 7 times. The relative standard deviations on the same day were between 2. 2% and 2. 9%, and the relative standard deviations on different day between 3,3% and 3. 5%. The method was applied to the analysis of waste circuit board and the results were consistent with those obtained by microwave digestion inductively coupled plasma atomic emission spectrometry.%研究了微波马弗炉加热处理样品,火焰原子吸收光谱法测定废旧电路板中金、银、铂、钯的方法.称取5.0g粉碎后废旧电路板样品,用微波马弗炉在550℃灼烧30 min分解有机物,用王水溶解样品,样品溶液中的金、银、铂、钯用火焰原子吸收光谱法进行测定.金、银、铂、钯的方法检出限分别为0.078、0.12、0.15和0.15 mg/mL;方法回收率在90%~108%之间;用本方法平行测定同一废旧电路板样品7次,日内相对标准偏差为2.2%~2.9%;日间相对标准偏差为3.3%~3.5%.将本方法用于废旧电路板分析,测得结果与微波消解—电感耦合等离子体发射光谱法一致.

  5. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>2011-2015 The World Journal of Diabetes Editorial Board now consists of 710 members,representing a team of worldwide experts in diabetes mellitus.They are from 56 countries,including Argentina(2),Australia(27),Austria(11),

  6. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 529 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 40 countries, including Argentina (1), Australia (7),

  7. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 529 members,representing a team of worldwide experts in biochemistry and molecular biology.They are from 40 countries,including Argentina(1),Australia(7),

  8. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 523 members,representing a team of worldwide experts in biochemistry and molecular biology.They are from 40 countries,including Argentina(1),Australia(7),

  9. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2009-2013The World Journal of Biological Chemistry Editorial Board consists of 529 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 40 countries, including Argentina (1), Australia (7),

  10. 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),

  11. 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),

  12. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 529 members,representing a team of worldwide experts in biochemistry and molecular biology.They are from 40 countries,including Argentina(1),Australia(7),

  13. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    2010-2013 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 188 members,representing a team of worldwide experts in gastrointestinal pharmacology and therapeutics research.They are from 36 countries,

  14. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2010-2013 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 188 members,representing a team of worldwide experts in gastrointestinal pharmacology and therapeutics research. They are from

  15. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2010-2013 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 188 members,representing a team of worldwide experts in gastrointestinal pharmacology and therapeutics research.They are from 36 countries,

  16. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2010-2013 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 188 members, representing a team of worldwide experts in pharmacology and therapeutics research. They are from 36 countries, including Australia (6), Austria (2),

  17. Resonance circuits for adiabatic circuits

    Directory of Open Access Journals (Sweden)

    C. Schlachta

    2003-01-01

    Full Text Available One of the possible techniques to reduces the power consumption in digital CMOS circuits is to slow down the charge transport. This slowdown can be achieved by introducing an inductor in the charging path. Additionally, the inductor can act as an energy storage element, conserving the energy that is normally dissipated during discharging. Together with the parasitic capacitances from the circuit a LCresonant circuit is formed.

  18. An improved logarithmic amplifier circuit for PDS microdensitometers

    Science.gov (United States)

    Anderson, C. M.; Slovak, M. H.; Michalski, D. E.

    1984-01-01

    A high speed logarithmic amplifier circuit for the Perkin-Elmer PDS microdensitometer is discussed. The circuit is designed around an Analog Devices 757p log-amp module. The amplifier produces undistorted profiles of rapidly changing, dense ( 4) images over the available range of scanning speeds. The circuit board was designed to replace directly the manufacturer supplied unit; neither electrical nor mechanical modifications of the basic PDS are required. The performance of the circuit is illustrated through its effects on the overall modulation transfer function of the instrument and by scans of a well exposed stellar image. Circuit diagrams and parts lists a mechanism for obtaining either circuit board layout art work or finished circuit boards are presented.

  19. Harmless research of printed circuit board sludge byAcidithiobacillus ferrooxidans%嗜酸氧化亚铁硫杆菌处理线路板行业污泥的无害化

    Institute of Scientific and Technical Information of China (English)

    李东明; 白建峰; 张承龙; 戴珏; 苑文仪; 邓明强; 毛文雄; 王景伟

    2015-01-01

    The sludge from printed circuit board (PCB) industry was treated harmlessly by the bioleaching method. In the experiment,Acidithiobacillus ferrooxidans (hereafter abbreviated asA.f), which was selected from the copper mine, was used in the bioleaching process. For the original state of the strain, the effect of leaching time, pH value, acclimation period, solid-to-liquid ratio, concentration of ferrous sulfate on bioleaching valuable metals from the sludge were investigated. The results showed that high concentrations of heavy metals in the solution would inhibit the leaching rate of metals by the strain when the solid-to-liquid ratio exceeded 1:20. But the tolerance of the strain could enhance through the continuous acclimation. With a five cycles of continuous domestication for the strain in the bioleaching solution, the ability of the strain leaching metals from the sludge was improved significantly. Leaching rates of Cu, Ni and Zn from the sludge could reach 78%, 53% and 74% respectively under the optical conditions, which were FeSO4•7H20concentration of 60g/L, pH value of 0.5, extraction time of 6days, ratio of solid-to-liquid of 1:10in 9K medium. So the environmentally friendly method would provide support for the PCB industry.%研究了一株用于浸出线路板中Cu的嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans简称:A.f菌)在高固液比下无害化处理线路板污泥的影响.实验以A.f菌为原始菌种,通过周期性的驯化培养,在不同的浸出条件下探究了生物浸出时间、培养基pH值、菌种驯化周期、固液比和硫酸亚铁浓度等因素对A.f菌浸出线路板行业污泥中有价金属的影响.结果表明:当固液比高于1:20时,溶液中高浓度的重金属对微生物浸出有抑制作用,但通过连续的驯化培养可以提高菌种的耐受性,在FeSO4·7H2O投加量为60g/L、9k培养基初始pH为0.5、浸出时间为6d、固液比为1:10的条件下, Cu

  20. 响应面法优化废印刷线路板的金萃取条件%Optimization of extraction of gold from waste printed circuit board using response surface methodology

    Institute of Scientific and Technical Information of China (English)

    朱晓光; 席晓丽; 聂祚仁; 马立文; 朱健健

    2013-01-01

      The sponge gold was obtained by using“breaking—removing low priced metal with sulfuric acid oxidation method—leaching gold—extracting gold with methyl isobutyl ketone (MIBK)—stripping gold”process. The statistical methods were used to analyze the impact of different factors on the extraction of Au (Ⅲ) using MIBK as extractant. The factorial designs with five factors and two levels were firstly used to evaluate the relative effects that might affect the extraction of gold from the waste printed circuit board with MIBK. The results show that the factors including the phase ratio of organic and aqueous, the reaction time and the temperature, have significant impacts on the extraction rate of gold. The phase ratio and reaction time have positive impacts on the gold extraction, while temperature has negative impact. Based on this, Box­Behnken central composite design combining with response surface methodology (RSM) was employed to optimize the most important affecting factors of the extraction rate. The optimum conditions for the extraction are the organic and aqueous phase ratio of 0.34, reaction time of 12.4 min and temperature of 28℃, which are calculated from an established quadratic equation of one variable regression model. Under the optimized conditions, the gold extraction rate can reach as high as 96.1%. At last, the organic phase is stripped with solution of oxalic acid (5%) to get sponge gold.%  对回收废线路板采用“破碎—氧化硫酸法分离贱金属—浸出金—甲基异丁酮溶剂萃取提金—反萃析金”工艺获得海绵金,采用统计学方法及Minitab15软件对甲基异丁酮(MIBK)萃取线路板中金的影响因素进行探讨和分析。针对萃金过程,首先采用析因设计法进行5因素2水平的部分析因试验设计,对MIBK萃金的影响因素进行筛选,发现相比、反应时间和反应温度对金萃取率有显著影响,而且相比时间的影响具有正效应,

  1. 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。

  2. Application of real-time holographic interferometry in the nondestructive inspection of electronic parts and assemblies

    Science.gov (United States)

    Wood, Craig P.; Trolinger, James D.

    1991-01-01

    Nondestructive inspection by holographic interferometry (HI) is quickly gaining acceptance in the electronics industry as a sensitive and accurate method of locating manufacturing and assembly flaws in a wide range of electronics, from individual components to assembled modules. This paper describes the specific application of real-time HI in the nondestructive analysis of circuit board heat exchangers and multiple-layer printed wiring boards to locate areas of debonding and delamination. In the application of HI, the choice of a stressing method is often as important as the choice of a specific HI technique. Methods for component stressing include thermal, vibrational, and pressure-induced stressing methods, and these are described in detail. In addition, two techniques for sensitivity enhancement, phase shift interferometry and beam tilt correction, are discussed in detail.

  3. GATING CIRCUITS

    Science.gov (United States)

    Merrill, L.C.

    1958-10-14

    Control circuits for vacuum tubes are described, and a binary counter having an improved trigger circuit is reported. The salient feature of the binary counter is the application of the input signal to the cathode of each of two vacuum tubes through separate capacitors and the connection of each cathode to ground through separate diodes. The control of the binary counter is achieved in this manner without special pulse shaping of the input signal. A further advantage of the circuit is the simplicity and minimum nuruber of components required, making its use particularly desirable in computer machines.

  4. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    2011-2015The World Journal of Gastrointestinal Oncology Editorial Board consists of 428 members,representing a team of worldwide experts in gastrointestinal oncology.They are from 40 countries,including Argentina(2),Australia(10),Belgium(5),Brazil(2),Canada(4),Chile(2),China(56),Czech Republic(1),Denmark(1),Finland(3),France

  5. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 523 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 40 countries, including Argentina (1), Australia (7), Austria (3), Belgium (6), Brazil (5),

  6. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 529 members, representing a team of worldwide experts in biochemistry and molecular biology.They are from 40 countries,including Argentina (1),Australia (7),Austria (2),Belgium (6),Brazil (5),Bulgaria (1),Canada (18),Chile (1),China

  7. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The World Journal of Biological Chemistry Editorial Board consists of 529 members,representing a team of worldwide experts in biochemistry and molecular biology.They are from 40 countries,including Argentina(1),Australia(7), Austria(2),Belgium(6),Brazil(5),Bulgaria(1),Canada(18),Chile(1),China(36),Czech Republic(1),Denmark

  8. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 391 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 38 countries, including Argentina (1), Australia (6), Austria (3), Belgium (6), Brazil (4), Bulgaria (1), Canada (15), Chile (1), China (28), Denmark (1), Finland (3), France

  9. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2009-2013The World Journal of Biological Chemistry Editorial Board consists of 529 members,representing a team of worldwide experts in biochemistry and molecular biology.They are from 40 countries,including Argentina(1),Australia(7),Austria(2),Belgium(6),

  10. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    2011-2015The World Journal of Diabetes Editorial Board now consists of 710 members,representing a team of worldwide experts in diabetes mellitus.They are from 56 countries,including Argentina(2),Australia(27),Austria(11),Belgium(5),Brazil(13),Canada(24),Chile(3),China(40),Cuba(1),Czech Republic(3),Denmark(15),Egypt(3),

  11. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    2009-2013The World Journal of Biological Chemistry Editorial Board consists of 523 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 40 countries, including Argentina (1), Australia (7), Austria (3), Belgium (6), Brazil (5), Bulgaria (1), Canada (20), Chile (1), China (36), Czech Republic (1), Denmark

  12. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    2009-2013The World Journal of Biological Chemistry Editorial Board consists of 529 members,representing a team of worldwide experts in biochemistry and molecular biology.They are from 40 countries,including Argentina(1),Australia(7),Austria(2),Belgium(6),Brazil(5),Bulgaria(1),Canada(18),Chile(1),China(36),Czech Republic(1),Denmark

  13. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 529 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 40 countries, including Argentina (1), Australia (7), Austria (2), Belgium (6), Brazil (5), Bulgaria (1), Canada

  14. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 523 members,representing a team of worldwide experts in biochemistry and molecular biology.They are from 40 countries,including Argentina(1),Australia(7), Austria(3),Belgium(6),Brazil(5),Bulgaria(1),Canada(20),Chile(1),China(36),Czech Republic(1),Denmark

  15. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2009-2013The World Journal of Biological Chemistry Editorial Board consists of 391 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 38 countries, including Argentina (1), Australia (6), Austria (3), Belgium (6), Brazil (4), Bulgaria (1), Canada (15), Chile (1), China (28), Denmark (1), Finland (3), France

  16. 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

  17. 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

  18. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2010-2013 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 188 members, representing a team of worldwide experts in gastrointestinal pharmacology and therapeutics research.They are from 36 countries,including Australia(6),Austria(2),Belgium(2),Brazil(1),Canada(7),China(19),Czech Republic(1)

  19. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2010-2013 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 188 members, representing a team of worldwide experts in gastrointestinal pharmacology and therapeutics research. They are from 36 countries, including Australia (6), Austria (2), Belgium (2), Brazil (1), Canada (7), China (19),

  20. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    2010-2013 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 188 members,representing a team of worldwide experts in gastrointestinal pharmacology and therapeutics research.They are from 36 countries,including Australia (6),Austria (2),Belgium (2),Brazil

  1. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    2010-2013 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 188 members,representing a team of worldwide experts in gastrointestinal pharmacology and therapeutics research.They are from 36 countries, including Australia(6),Austria(2),Belgium

  2. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2010-2013 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 188 members,representing a team of worldwide experts in gastrointestinal pharmacology and therapeutics research.They are from 36 countries,including Australia(6),Austria(2),Belgium(2),Brazil(1),Canada(7),China(19),Czech Republic(1),

  3. Neural Circuits on a Chip

    Directory of Open Access Journals (Sweden)

    Md. Fayad Hasan

    2016-09-01

    Full Text Available Neural circuits are responsible for the brain’s ability to process and store information. Reductionist approaches to understanding the brain include isolation of individual neurons for detailed characterization. When maintained in vitro for several days or weeks, dissociated neurons self-assemble into randomly connected networks that produce synchronized activity and are capable of learning. This review focuses on efforts to control neuronal connectivity in vitro and construct living neural circuits of increasing complexity and precision. Microfabrication-based methods have been developed to guide network self-assembly, accomplishing control over in vitro circuit size and connectivity. The ability to control neural connectivity and synchronized activity led to the implementation of logic functions using living neurons. Techniques to construct and control three-dimensional circuits have also been established. Advances in multiple electrode arrays as well as genetically encoded, optical activity sensors and transducers enabled highly specific interfaces to circuits composed of thousands of neurons. Further advances in on-chip neural circuits may lead to better understanding of the brain.

  4. 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.

  5. Development of synaptic connectivity in the retinal direction selective circuit.

    Science.gov (United States)

    Morrie, Ryan D; Feller, Marla B

    2016-10-01

    Direction selectivity is a classic neuronal computation that has been described in many different sensory systems. The circuit basis of this computation is perhaps best understood in the retina, where direction selectivity is the result of asymmetric connectivity patterns between excitatory and inhibitory circuit components. Retinal direction selective circuits emerge before eye-opening, though components of the circuit undergo refinement after vision begins. These features make the direction selective circuit a rich model in which to investigate neuronal circuit assembly. In this Opinion, we highlight recent experiments investigating the contribution of various molecular cues, as well as neuronal activity, to the development of the retinal direction selective circuit.

  6. Technology characteristics and concerns arising in the design and fabrication of an entire signal processor using gallium arsenide integrated circuits

    Science.gov (United States)

    Naused, Barbara A.; Samson, Mark L.; Schwab, Daniel J.; Gilbert, Barry K.

    Various GaAs transistor and gate technologies that have been developed since 1980 are analyzed. The characteristics of GaAs logic gates and ICs and the buffered FET logic, Shottky diode FET logic, direct coupled FET logic, and heterojunction integrated injection logic used to implement GaAs gate arrays of LSI complexity are described. The use of digital GaAs in a complex target signal processor, the Advanced Onboard Signal Processor (AOSP), is studied. Data from the testing of GaAs components for the AOSP at the wafer probe, package, and assembled circuit board levels are examined.

  7. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    2014-2017 The World Journal of Biological Chemistry Editorial Board consists of 473 members,representing a team of worldwide experts in biochemistry and molecular biology.They are from 47 countries,including Argentina(1),Australia(9),Austria(4),Belgium(5),Brazil(10),Canada(12),Chile(1),China(44),Cyprus(1),Czech Repoublic(1),Egypt(3),Finland(1),France(16),Germany(12),Greece(6),Hungary(1),India(8),Iran(3),Ireland(1),Israel(7),Italy

  8. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    2010-2015 The World Journal of Stem Cells Editorial Board consists of 719 members,representing a team of worldwide experts in infectious diseases.They are from 44 countries,including Argentina(2),Australia(10),Austria(6),Belgium(3),Brazil(10),Canada(16),China(74),Cyprus(1),Czech Republic(5),Denmark(7),Egypt(2),Finland(3),France(19),Germany(36),Greece(1),Hungary(3),India(10),Iran(9),Ireland(4),Israel(10),Italy(52),Japan(55),Jordan

  9. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    2014-2017The World Journal of Cardiology Editorial Board consists of 410 members,representing a team of worldwide experts in cardiology.They are from 46 countries,including Argentina(3),Australia(7),Austria(6),Belgium(2),Brazil(8),Canada(11),China(37),Croatia(1),Cuba(1),Cyprus(1),Czech Repoublic(2),Denmark(3),Egypt(1),Finland(3),France(3),Germany(31),Greece(10),Hungary(5),India(4),Iran(2),

  10. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    <正>2014-2017The World Journal of Cardiology Editorial Board consists of 410 members,representing a team of worldwide experts in cardiology.They are from 46 countries,including Argentina(3),Australia(7),Austria(6),Belgium(2),Brazil(8),Canada(11),China(37),Croatia(1),Cuba(1),Cyprus(1),Czech Repoublic(2),Denmark(3),Egypt(1),Finland(3),France(3),Germany(31),Greece(10),Hungary(5),India(4),Iran(2),Ireland(1),Israel(4),Italy(61),Japan(32),Koso

  11. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>2014-2017 The World Journal of Hepatology Editorial Board consists of 469 members,representing a team of worldwide experts in hepatology.They are from 53 countries,including Algeria(1),Argentina(6),Armenia(1),Australia(1),Austria(4),Bangladesh(2),Belgium(3),Botswana(2),Brazil(13),Bulgaria(2),Canada(3),Chile(1),China(98),Czech Repoublic(1),Denmark(2),Egypt(12),France(6),Germany(19),Greece(11),Hungary(5),India(15),Indonesia

  12. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2010-2013 The World Journal of Gastrointestinal Pharmacology and Therapeutics Editorial Board consists of 188 members, representing a team of worldwide experts in gastrointestinal pharmacology and therapeutics research. They are from 36 countries, including Australia (6), Austria (2), Belgium (2), Brazil (1), Canada (7), China (19), Czech (1), Denmark (1), Egypt (1), Estonia (1), Finland (1), France (1), Germany (5), Greece (4), Hungary (1), India (6), Iran (1), Ireland (1), Israel (3), Italy (20),

  13. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 387 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 38 countries, including Argentina (1), Australia (5), Austria (3), Belgium (6), Brazil (4), Bulgaria (1), Canada (15), Chile (1), China (28), Denmark (1), Finland (3), France (11), Germany (15), Greece (2), India (9), Iran (2), Israel (4), Italy (22), Japan (29), Lithuania (1), Mauritius (1),

  14. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 370 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 38 countries, including Argentina (1), Australia (5), Austria (3), Belgium (6), Brazil (3), Bulgaria (1), Canada (15), Chile (1), China (27), Denmark (1), Finland (3), France (10), Germany (15), Greece (2), India (8), Iran (2), Israel (3), Italy (21), Japan (28), Lithuania (1), Mauritius (1), Mexico

  15. Buddy Board

    DEFF Research Database (Denmark)

    Enggaard, Helle; Moselund, Lene

    2015-01-01

    Projekt ’BuddyBoard’ er kommet i stand via et samarbejde mellem Frederikshavn kommune, Bunker43 og Lab. X. Afdeling en ’Havly’ på Sæby Ældrecenter fungerer som living lab, hvilket betyder, at det udgør et levende laboratorium for udvikling og afprøvning af teknologi (Schultz, 2013). Projektet er....... Bunker43 har udviklet en teknologi (BuddyBoard) til hurtig formidling af billeder fra pårørende og personale til beboere på institutioner. Pårørende og personale uploader billeder via en APP eller en hjemmeside og har mulighed for at tilføje en kort forklarende tekst til hvert billede. Beboeren ser...... billederne via en tablet. Systemet bygger på et simpelt og brugervenligt design, så ældre med kognitive og/eller fysiske funktionsnedsættelser kan anvende teknologien. BuddyBoard fungerer via internettet, og billederne gemmes på en sikret server hos udbyderen, som er Bunker43. Intentionerne med BuddyBoard er...

  16. Bottom-up organic integrated circuits

    NARCIS (Netherlands)

    Smits, Edsger C. P.; Mathijssen, Simon G. J.; van Hal, Paul A.; Setayesh, Sepas; Geuns, Thomas C. T.; Mutsaers, Kees A. H. A.; Cantatore, Eugenio; Wondergem, Harry J.; Werzer, Oliver; Resel, Roland; Kemerink, Martijn; Kirchmeyer, Stephan; Muzafarov, Aziz M.; Ponomarenko, Sergei A.; de Boer, Bert; Blom, Paul W. M.; de Leeuw, Dago M.

    2008-01-01

    Self- assembly - the autonomous organization of components into patterns and structures(1) - is a promising technology for the mass production of organic electronics. Making integrated circuits using a bottom- up approach involving self- assembling molecules was proposed(2) in the 1970s. The basic b

  17. 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...

  18. 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.

  19. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    2014-2017 The World Journal of Radiology Editorial Board consists of 365 members,representing a team of worldwide experts in radiology.They are from 36 countries,including Afghanistan(1),Argentina(2),Australia(5),Austria(7),Belgium(2),Brazil(8),Canada(6),Chile(1),China(43),Croatia(1),Denmark(4),Egypt(6),France(5),Germany(22),Greece(10),India(12),Iran(6),Ireland(2),Israel(3),Italy(47),Japan(13),Netherlands(1),New Zealand(1),Pakistan(1),Poland(2),Portugal(1),Serbia(1),Singapore(3),Slovakia(1),South Korea(18),Spain(4),Sweden(2),Switzerland(4),Thailand(1),Turkey(26),United Kingdom(11),and United States(82).

  20. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 529 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 40 countries, including Argentina (1), Australia (7), Austria (2), Belgium (6), Brazil (5), Bulgaria (1), Canada (18), Chile (1), China (36), Czech Republic (1), Denmark (1), Finland (3), France (14), Germany (17), Greece (4), India (9), Iran (2), Israel (5), Italy (26), Japan (43), Lithuania (1), Mauritius (1), Mexico (2), Netherlands (7), New Zealand (2), Norway (4), Portugal (4), Romania (1), Russia (2),

  1. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    2012-2016 The World Journal of Gastrointestinal Surgery Editorial Board consists of 341 members,representing a team of worldwide experts in pediatrics.They are from 37 countries,including Australia(6),Austria(2),Belgium(6),Brazil(9),Bulgaria(2),Canada(8),China(29),Denmark(1),Finland(2),France(9),Germany(21),Greece(7),India(11),Ireland(3),Israel(3),Italy(50),Jamaica(1),Japan(47),Lithuania(1),Malaysia(1),Netherlands(11),Pakistan(1),Poland(1),Portugal(1),Russia(1),Saudi Arabia(1),Serbia(2),Singapore(5),South Korea(8),Spain(5),Sweden(2),Switzerland(3),Thailand(2),Tunisia(1),Turkey(8),United Kingdom(11),and United States(59).

  2. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 391 members, representing a team of worldwide experts in biochemistry and molecular biology. They are from 38 countries, including Argentina (1), Australia (6), Austria (3), Belgium (6), Brazil (4), Bulgaria (1), Canada (15), Chile (1), China (28), Denmark (1), Finland (3), France (11), Germany (15), Greece (2), India (9), Iran (2), Israel (4), Italy (22), Japan (29), Lithuania (1), Mauritius (1), Mexico (2), Netherlands (5), New Zealand (1), Norway (1), Portugal (4), Russia (1), Singapore (3), South Africa (1),

  3. Digital integrated circuits

    Science.gov (United States)

    Polasek, P.; Halamik, J.

    1984-05-01

    The term semicustom designed integrated circuits denotes integrated circuits of an all purpose character in which the production of chips is completed by using one to three custom design stencil type exposure masks. This involves in most cases interconnecting masks that are used to devise the circuit function desired by the customer. Silicon plates with an all purpose gate matrix are produced up to the interconnection level and can be kept at this phase in storage, after which a customer's specific demands can be met very expediently. All purpose logic fields containing 200 logic gates on a chip and an all purpose chip to be expanded to 1,000 logic gates are discussed. The technology facilitates the devising of fast gates with a delay of approximately 5 ns and power dissipation of 1 mW. In assembly it will be possible to make use of the entire assortment of the currently used casings with 16, 18, 20, 24, 28 and 40 outlets. In addition to the development of the mentioned technology, a general methodology for design of the mentioned gate fields is currently under way.

  4. PC board mount corrosion sensitive sensor

    Science.gov (United States)

    Robinson, Alex L.; Casias, Adrian L.; Pfeifer, Kent B.; Laguna, George R.

    2016-03-22

    The present invention relates to surface mount structures including a capacitive element or a resistive element, where the element has a property that is responsive to an environmental condition. In particular examples, the structure can be optionally coupled to a printed circuit board. Other apparatuses, surface mountable structures, and methods of use are described herein.

  5. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    2014-2017 EDITORS-IN-CHIEFKai U Juergens,BremenStuart M Grieve,SydneyWai-Kit Lee,FitzroyTarik Zine Belhocine,TorontoJames Chow,Toronto The World Journal of Radiology Editorial Board consists of 365 members,representing a team of worldwide experts in radiology.They are from 36 countries,including Afghanistan(1),Argentina(2),Australia(5),Austria(7),Belgium(2),Brazil(8),Canada(6),Chile(1),China(43),Croatia(1),Denmark(4),Egypt(6),France(5),Germany(22),Greece(10),India(12),Iran(6),Ireland(2),Israel(3),Italy(47),Japan(13),Netherlands(1),New Zealand(1),Pakistan(1),Poland(2),Portugal(1),Serbia(1),Singapore(3),Slovakia(1),South Korea(18),Spain(4),Sweden(2),Switzerland(4),Thailand(1),Turkey(26),United Kingdom(11),and United States(82).

  6. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>2009-2013 The World Journal of Radiology Editorial Board consists of 319 members,representing a team of worldwide experts in radiology.They are from 40 countries,including Australia(3),Austria(4),Belgium(5),Brazil(3),Canada(9),Chile(1),China(25),Czech(1),Denmark(1),Egypt(4),Estonia(1),Finland(1),France(6),Germany(17),Greece(8),Hungary(1),India(9),Iran(5),Ireland(1),Israel(4),Italy(28),Japan(14),Lebanon(1),Libya(1),Malaysia(2),Mexico(1),Netherlands(4),New Zealand(1),Norway(1),Saudi Arabia(3),Serbia(1),Singapore(2),Slovakia(1),South Korea(16),Spain(8),Switzerland(5),Thailand(1),Turkey(20),United Kingdom(16),and United States(82).

  7. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    2009-2013 The World Journal of Biological Chemistry Editorial Board consists of 391 members,representing a team of worldwide experts in biochemistry and molecular biology. They are from 38 countries,including Argentina (1),Australia (6),Austria (3),Belgium (6),Brazil (4),Bulgaria (1),Canada (15),Chile (1),China (28),Denmark (1),Finland (3),France (11),Germany (15),Greece (2),India (9),Iran (2),Israel (4),Italy (22),Japan (29),Lithuania (1),Mauritius (1),Mexico (2),Netherlands (5),New Zealand (1),Norway (1),Portugal (4),Russia (1),Singapore (3),South Africa (1),South Korea (14),Spain (10),Sweden (3),Switzerland (2),Thailand (1),Turkey (1),Ukraine (1),United Kingdom (15),and United States (161).

  8. Editorial Board

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    2011-2015The 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(1),France(5),Germany(21),Greece(6),Hungary(4),India(18),Iran(6),Ireland(1),Israel(4),Italy(35),Japan(34),Lebanon(1),Lithuania(3),Mexico(2),Netherlands(10),New Zealand(2),Norway(2),Pakistan(2),Philippines(1),Poland(3),Portugal(2),Romania(1),Russia(1),Saudi Arabia(2),Singapore(3),Slovenia(1),South Africa(1),South Korea(16),Spain(13),Sweden(3),Switzerland(1),Thailand(4),Turkey(7),United Kingdom(20),and United States(84).

  9. Development of larval motor circuits in Drosophila.

    Science.gov (United States)

    Kohsaka, Hiroshi; Okusawa, Satoko; Itakura, Yuki; Fushiki, Akira; Nose, Akinao

    2012-04-01

    How are functional neural circuits formed during development? Despite recent advances in our understanding of the development of individual neurons, little is known about how complex circuits are assembled to generate specific behaviors. Here, we describe the ways in which Drosophila motor circuits serve as an excellent model system to tackle this problem. We first summarize what has been learned during the past decades on the connectivity and development of component neurons, in particular motor neurons and sensory feedback neurons. We then review recent progress in our understanding of the development of the circuits as well as studies that apply optogenetics and other innovative techniques to dissect the circuit diagram. New approaches using Drosophila as a model system are now making it possible to search for developmental rules that regulate the construction of neural circuits.

  10. Grounding and shielding circuits and interference

    CERN Document Server

    Morrison, Ralph

    2016-01-01

    Applies basic field behavior in circuit design and demonstrates how it relates to grounding and shielding requirements and techniques in circuit design This book connects the fundamentals of electromagnetic theory to the problems of interference in all types of electronic design. The text covers power distribution in facilities, mixing of analog and digital circuitry, circuit board layout at high clock rates, and meeting radiation and susceptibility standards. The author examines the grounding and shielding requirements and techniques in circuit design and applies basic physics to circuit behavior. The sixth edition of this book has been updated with new material added throughout the chapters where appropriate. The presentation of the book has also been rearranged in order to reflect the current trends in the field.

  11. Computer-Assisted Experiments with Oscillatory Circuits

    Science.gov (United States)

    Fernandes, J. C.; Ferraz, A.; Rogalski, M. S.

    2010-01-01

    A basic setup for data acquisition and analysis from an oscillatory circuit is described, with focus on its application as either low-pass, high-pass, band-pass or band-reject frequency filter. A homemade board containing the "RLC" elements allows for the interchange of some of them, in particular, for the easy change of the "R" value, and this…

  12. Affective Circuits

    DEFF Research Database (Denmark)

    to the intersecting streams of goods, people, ideas, and money as they circulate between African migrants and their kin who remain back home. They also show the complex ways that emotions become entangled in these exchanges. Examining how these circuits operate in domains of social life ranging from child fosterage......Moving between Africa and Europe, the book explores the many ways migrants sustain and rework family ties and intimate relationships at home and abroad. It demonstrates how their quotidian efforts—on such a mass scale—contribute to a broader process of social regeneration. The contributors point...

  13. Collective of mechatronics circuit

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1987-02-15

    This book is composed of three parts, which deals with mechatronics system about sensor, circuit and motor. The contents of the first part are photo sensor of collector for output, locating detection circuit with photo interrupts, photo sensor circuit with CdS cell and lamp, interface circuit with logic and LED and temperature sensor circuit. The second part deals with oscillation circuit with crystal, C-R oscillation circuit, F-V converter, timer circuit, stability power circuit, DC amp and DC-DC converter. The last part is comprised of bridge server circuit, deformation bridge server, controlling circuit of DC motor, controlling circuit with IC for PLL and driver circuit of stepping motor and driver circuit of Brushless.

  14. Demonstrating the Effect of Particle Impact Dampers on the Random Vibration Response and Fatigue Life of Printed Wiring Assemblies

    Science.gov (United States)

    Knight, Brent; Montgomery, Randall; Geist, David; Hunt, Ron; LaVerde, Bruce; Towner, Robert

    2013-01-01

    In a recent experimental study, small Particle Impact Dampers (PID) were bonded directly to the surface of printed circuit board (PCB) or printed wiring assemblies (PWA), reducing the random vibration response and increasing the fatigue life. This study provides data verifying practicality of this approach. The measured peak strain and acceleration response of the fundamental out of plane bending mode was significantly attenuated by adding a PID device. Attenuation of this mode is most relevant to the fatigue life of a PWA because the local relative displacements between the board and the supported components, which ultimately cause fatigue failures of the electrical leads of the board-mounted components are dominated by this mode. Applying PID damping at the board-level of assembly provides mitigation with a very small mass impact, especially as compared to isolation at an avionics box or shelf level of assembly. When compared with other mitigation techniques at the PWA level (board thickness, stiffeners, constrained layer damping), a compact PID device has the additional advantage of not needing to be an integral part of the design. A PID can simply be bonded to heritage or commercial off the shelf (COTS) hardware to facilitate its use in environments beyond which it was originally qualified. Finite element analysis and test results show that the beneficial effect is not localized and that the attenuation is not due to the simple addition of mass. No significant, detrimental reduction in frequency was observed. Side-by-side life testing of damped and un-damped boards at two different thicknesses (0.070" and 0.090") has shown that the addition of a PID was much more significant to the fatigue life than increasing the thickness. High speed video, accelerometer, and strain measurements have been collected to correlate with analytical results.

  15. Research of thermal stress between long linear MCT arrays and lead board using FEM

    Science.gov (United States)

    Wu, Wen; Wu, Yonghong; Liu, Dafu

    2010-10-01

    For the long wavelength infrared detection, HgCdTe (MCT) photoconductive devices are selected as the core of next-generation meteorological because of its mature fabrication technique and stable performance. During the assembly process, an innovative multilayer ceramic board providing mechanical support is designed as the electrical interconnection between MCT chips and external circuits for cryogenic application. Furthermore, due to its brittleness, long linear MCT device is normally glued to sapphire substrates on the multilayer ceramic board with cryogenic glue. Thus, it can be seen clearly that the assembly structure is a multilayer configuration which comprises various kinds of materials, including ceramic broad, sapphire, MCT and glues. As a result, the difference in Thermal Expansion Coefficient (TEC) between the layers could create the potential to introduce thermal stress at working environmental temperature (approximately 70K), which could result in device performance degradation, even die crack. This article analyzes the thermal stress between long linear MCT devices and a multilayer ceramic board by using Finite Element Method (FEM). According to analysis results, two factors are revealed as the most significant causes for introducing thermal stress: one is the sapphire substrate thickness; the other is the parameters of various materials, for instance Yong's modulus and TEC. Since the structure of MCT detector is determined by system requirements and is under the limitation of manufacture technology, this article reveals two effective approaches to reduce the unavoidable thermal stress: first, choosing the appropriate thickness of ceramic board which is made by Al2O3; second, adding another metal cushion Invar. With the above considerations, the distribution of thermal stress is simulated using FEM under different parameter conditions. Based on the results of simulations, an optimal design of package structure which could improve the reliability of

  16. Electrochemical cell with internal circuit interrupter

    Energy Technology Data Exchange (ETDEWEB)

    Georgopoulos, P.; Langkau, J.

    1989-08-08

    This patent describes an electrochemical cell. It comprises an electrode assembly containing a positive and negative electrode; a housing containing the electrode assembly, and containing a means for providing a terminal for one of the electrodes; a cover assembly containing a means for providing a terminal opposite the terminal of the housing to thereby establish an electrical circuit in the cell; and a current collector member disposed in the circuit and in physical contact with one of the electrodes. The collector is comprised of a shape-memory alloy, and having a base portion and a plurality of legs extending from the base portion; wherein the collector provides a means for disconnecting the electrical circuit in the cell when the internal temperature of the cell rises.

  17. Commutation circuit for an HVDC circuit breaker

    Science.gov (United States)

    Premerlani, William J.

    1981-01-01

    A commutation circuit for a high voltage DC circuit breaker incorporates a resistor capacitor combination and a charging circuit connected to the main breaker, such that a commutating capacitor is discharged in opposition to the load current to force the current in an arc after breaker opening to zero to facilitate arc interruption. In a particular embodiment, a normally open commutating circuit is connected across the contacts of a main DC circuit breaker to absorb the inductive system energy trapped by breaker opening and to limit recovery voltages to a level tolerable by the commutating circuit components.

  18. The Recovery of Metals from Printed Circuit Board Scrap by Bio-hydrometallurgical Processing-A Review%基于生物湿法冶金的废旧印刷线路板金属资源化研究进展

    Institute of Scientific and Technical Information of China (English)

    谌书; 杨远坤; 廖广丹; 陈梦君; 陈海焱

    2013-01-01

    随着科技的快速发展,电子产品数量的急剧增加及其使用周期的不断缩短,全球面临着前所未有的电子废物产生浪潮.一种数量巨大的典型电子废弃物—废旧印刷线路板如何实现绿色、低能耗的处理已成为当前电子废弃物处理中关键问题之一.利用微生物湿法冶金技术将废旧印刷线路板中金属浸出,制备高纯金属,已成为21世纪电子废物处理的前沿技术,同时电子废物的微生物湿法冶金机制探讨已成为近年来的研究热点.本文重点分析微生物湿法冶金处理废旧印刷线路板浸提过程中的微生物种类、影响浸提因素、微生物的浸出机制以及今后需要继续研究的问题.%With the rapid development of science and technology,the electric and electronic equipment has been developed,applied,and consumed worldwide at a very high speed.Subsequently,the ever increasing amount of waste electric and electronic equipment (WEEE) has become a common problem facing the world.One kind of a large number of electronic wastes is printed circuit board scrap (PCBs) as typical WEEE waste.Eco-friendly and energy-saving processes are urgently needed to recycle metals from PCBs and this has become one of the complex problem.Printed circuit board scrap metals were leached by microbial hydrometallurgical technology,followed by production of high purity metals directly.This has become the 21st century state-of-art of e-waste processing technologies.More attention has been played to recycling PCBs by microbial hydrometallurgical process.This article reviewed microbial species,the extraction of factors,microbial leaching mechanisms,and future trends needed in the issues during microbial hydrometallurgical extraction metals in PCBs.

  19. Design of drive circuit of laser diode

    Science.gov (United States)

    Ran, Yingying; Huang, Xuegong; Xu, Xiaobin

    2016-10-01

    Aiming at the difficult problem of high precision frequency stabilization of semiconductor laser diode, the laser frequency control is realized through the design of the semiconductor drive system. Above all, the relationship between the emission frequency and the temperature of LD is derived theoretically. Then the temperature corresponding to the stable frequency is obtained. According to the desired temperature stability of LD, temperature control system is designed, which is composed of a temperature setting circuit, temperature gathering circuit, the temperature display circuit, analog PID control circuit and a semiconductor refrigerator control circuit module. By sampling technology, voltage of platinum resistance is acquired, and the converted temperature is display on liquid crystal display. PID analog control circuit controls speed stability and precision of temperature control. The constant current source circuit is designed to provide the reference voltage by a voltage stabilizing chip, which is buffered by an operational amplifier. It is connected with the MOSFET to drive the semiconductor laser to provide stable current for the semiconductor laser. PCB circuit board was finished and the experimental was justified. The experimental results show that: the design of the temperature control system could achieve the goal of temperature monitoring. Meanwhile, temperature can be stabilized at 40°C +/- 0.1°C. The output voltage of the constant current source is 2 V. The current is 35 mA.

  20. An innovate method to recycle non-metallic materials from waste printed circuit board.%废线路板非金属物料再生利用新型工艺研究

    Institute of Scientific and Technical Information of China (English)

    段华波; 李金惠; 王斯婷

    2012-01-01

    The reuse of non-metallic material separated from PWBs residues before and after thermo-shocked pretreatment was investigated. With the blending of various additives from silane coupling agents, lubricant agents, anti-oxidizing agents to processing modifier, the non-metallic material could be filled to produce polymeric composite materials subjected to the injection and molding processes. Said method was also appropriate to thermo-shocked non-metallic material. The mechanical property was qualified by compared with the standard limit of related composite materials. The maximum amount of recyclate that could be added to a composite board was 30% of weight, with the additive agents of: silane coupling agents (1%), lubricant agents (1%), anti-oxidizing agents (1%) and processing modifier (5%).%以加热改性处理前后的废线路板非金属物料为对象,对其再生利用工艺进行了研究.通过添加硅烷偶联剂、润滑剂、抗氧化剂和改性剂等助剂改性共混,基于挤出注塑成型工艺过程,可制备废线路板非金属物料填充增强聚丙烯复合板材,该工艺同时可适合一定温度条件下加热改性处理后的非金属物料,其主要力学性能符合相关制品产品质量标准.确定的优化参数为:非金属物料添加质量分数30%,添加助剂包括硅烷偶联剂(1%)、润滑剂(1%)、抗氧化剂(1%)和改性剂(5%).

  1. Analog circuit design designing dynamic circuit response

    CERN Document Server

    Feucht, Dennis

    2010-01-01

    This second volume, Designing Dynamic Circuit Response builds upon the first volume Designing Amplifier Circuits by extending coverage to include reactances and their time- and frequency-related behavioral consequences.

  2. Analog circuit design designing waveform processing circuits

    CERN Document Server

    Feucht, Dennis

    2010-01-01

    The fourth volume in the set Designing Waveform-Processing Circuits builds on the previous 3 volumes and presents a variety of analog non-amplifier circuits, including voltage references, current sources, filters, hysteresis switches and oscilloscope trigger and sweep circuitry, function generation, absolute-value circuits, and peak detectors.

  3. Low Noise Readout Circuit for Biosensor SoC

    Institute of Scientific and Technical Information of China (English)

    PAN Yin-song; KONG Mou-fu; LI Xiang-quan; WANG Li

    2008-01-01

    Presented is a low noise interface circuit that is tuned to the needs of self-assembly monolayers biosensor SoC. The correlated double sampling(CDS) unit of the readout circuit can reduce 1/f noise, KTC noise and fixed noise of micro arrays effectively. The circuit is simulated in a 0.6 μm/level 7 standard CMOS process, and the simulated results show the output voltage has a good linearity with the transducing current of the micro arrays. This is a novel circuit including four amplifiers sharing a common half-circuit and the noise reducing CDS unit. It could be widely used for micro array biosensors.

  4. Effects of smoke on functional circuits

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.J.

    1997-10-01

    Nuclear power plants are converting to digital instrumentation and control systems; however, the effects of abnormal environments such as fire and smoke on such systems are not known. There are no standard tests for smoke, but previous smoke exposure tests at Sandia National Laboratories have shown that digital communications can be temporarily interrupted during a smoke exposure. Another concern is the long-term corrosion of metals exposed to the acidic gases produced by a cable fire. This report documents measurements of basic functional circuits during and up to 1 day after exposure to smoke created by burning cable insulation. Printed wiring boards were exposed to the smoke in an enclosed chamber for 1 hour. For high-resistance circuits, the smoke lowered the resistance of the surface of the board and caused the circuits to short during the exposure. These circuits recovered after the smoke was vented. For low-resistance circuits, the smoke caused their resistance to increase slightly. A polyurethane conformal coating substantially reduced the effects of smoke. A high-speed digital circuit was unaffected. A second experiment on different logic chip technologies showed that the critical shunt resistance that would cause failure was dependent on the chip technology and that the components used in the smoke exposures were some of the most smoke tolerant. The smoke densities in these tests were high enough to cause changes in high impedance (resistance) circuits during exposure, but did not affect most of the other circuits. Conformal coatings and the characteristics of chip technologies should be considered when designing circuitry for nuclear power plant safety systems, which must be highly reliable under a variety of operating and accident conditions. 10 refs., 34 figs., 18 tabs.

  5. Single-mode glass waveguide technology for optical interchip communication on board level

    Science.gov (United States)

    Brusberg, Lars; Neitz, Marcel; Schröder, Henning

    2012-01-01

    The large bandwidth demand in long-distance telecom networks lead to single-mode fiber interconnects as result of low dispersion, low loss and dense wavelength multiplexing possibilities. In contrast, multi-mode interconnects are suitable for much shorter lengths up to 300 meters and are promising for optical links between racks and on board level. Active optical cables based on multi-mode fiber links are at the market and research in multi-mode waveguide integration on board level is still going on. Compared to multi-mode, a single-mode waveguide has much more integration potential because of core diameters of around 20% of a multi-mode waveguide by a much larger bandwidth. But light coupling in single-mode waveguides is much more challenging because of lower coupling tolerances. Together with the silicon photonics technology, a single-mode waveguide technology on board-level will be the straight forward development goal for chip-to-chip optical interconnects integration. Such a hybrid packaging platform providing 3D optical single-mode links bridges the gap between novel photonic integrated circuits and the glass fiber based long-distance telecom networks. Following we introduce our 3D photonic packaging approach based on thin glass substrates with planar integrated optical single-mode waveguides for fiber-to-chip and chip-to-chip interconnects. This novel packaging approach merges micro-system packaging and glass integrated optics. It consists of a thin glass substrate with planar integrated singlemode waveguide circuits, optical mirrors and lenses providing an integration platform for photonic IC assembly and optical fiber interconnect. Thin glass is commercially available in panel and wafer formats and characterizes excellent optical and high-frequency properties. That makes it perfect for microsystem packaging. The paper presents recent results in single-mode waveguide technology on wafer level and waveguide characterization. Furthermore the integration in a

  6. Hybrid CMOS/Nanodevice Integrated Circuits Design and Fabrication

    Science.gov (United States)

    2008-08-25

    This approach combines a semiconductor transistor system with a nanowire crossbar, with simple two-terminal nanodevices self-assembled at each...hybrid CMOS/nanodevice integrated circuits [10-12]. Such circuit combines a semiconductor transistors system with a nanowire crossbar, with simple two...both with and without embedded metallic clusters), self-assembled molecular monolayers, and thin chalcogenide and crystalline perovskite layers [20

  7. The Short, Productive Board Meeting

    Science.gov (United States)

    McAdams, Donald R.

    2005-01-01

    Board meetings are the time and place where school boards act. In fact, only when coming together as a body in a legal meeting do school board members become a board. Effective board meetings are the first prerequisite for an effective board. Furthermore, what parents and voters see at board meetings determines largely what they think about their…

  8. Solid-state circuits

    CERN Document Server

    Pridham, G J

    2013-01-01

    Solid-State Circuits provides an introduction to the theory and practice underlying solid-state circuits, laying particular emphasis on field effect transistors and integrated circuits. Topics range from construction and characteristics of semiconductor devices to rectification and power supplies, low-frequency amplifiers, sine- and square-wave oscillators, and high-frequency effects and circuits. Black-box equivalent circuits of bipolar transistors, physical equivalent circuits of bipolar transistors, and equivalent circuits of field effect transistors are also covered. This volume is divided

  9. Simple Autonomous Chaotic Circuits

    Science.gov (United States)

    Piper, Jessica; Sprott, J.

    2010-03-01

    Over the last several decades, numerous electronic circuits exhibiting chaos have been proposed. Non-autonomous circuits with as few as two components have been developed. However, the operation of such circuits relies on the non-ideal behavior of the devices used, and therefore the circuit equations can be quite complex. In this paper, we present two simple autonomous chaotic circuits using only opamps and linear passive components. The circuits each use one opamp as a comparator, to provide a signum nonlinearity. The chaotic behavior is robust, and independent of nonlinearities in the passive components. Moreover, the circuit equations are among the algebraically simplest chaotic systems yet constructed.

  10. 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

  11. Solenoid-Simulation Circuit

    Science.gov (United States)

    Simon, R. A.

    1986-01-01

    Electrical properties of solenoids imitated for tests of control circuits. Simulation circuit imitates voltage and current responses of two engine-controlling solenoids. Used in tests of programs of digital engine-control circuits, also provides electronic interface with circuits imitating electrical properties of pressure sensors and linear variable-differential transformers. Produces voltages, currents, delays, and discrete turnon and turnoff signals representing operation of solenoid in engine-control relay. Many such circuits used simulating overall engine circuitry.

  12. Pilot Boarding Areas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pilot boarding areas are locations at sea where pilots familiar with local waters board incoming vessels to navigate their passage to a destination port. Pilotage is...

  13. Departmental Appeals Board Decisions

    Data.gov (United States)

    U.S. Department of Health & Human Services — Decisions issued by the Chair and Board Members of the Departmental Appeals Board concerning determinations in discretionary, project grant programs, including...

  14. OptoZIF Drive: a 3D printed implant and assembly tool package for neural recording and optical stimulation in freely moving mice

    Science.gov (United States)

    Freedman, David S.; Schroeder, Joseph B.; Telian, Gregory I.; Zhang, Zhengyang; Sunil, Smrithi; Ritt, Jason T.

    2016-12-01

    Objective. Behavioral neuroscience studies in freely moving rodents require small, light-weight implants to facilitate neural recording and stimulation. Our goal was to develop an integrated package of 3D printed parts and assembly aids for labs to rapidly fabricate, with minimal training, an implant that combines individually positionable microelectrodes, an optical fiber, zero insertion force (ZIF-clip) headstage connection, and secondary recording electrodes, e.g. for electromyography (EMG). Approach. Starting from previous implant designs that position recording electrodes using a control screw, we developed an implant where the main drive body, protective shell, and non-metal components of the microdrives are 3D printed in parallel. We compared alternative shapes and orientations of circuit boards for electrode connection to the headstage, in terms of their size, weight, and ease of wire insertion. We iteratively refined assembly methods, and integrated additional assembly aids into the 3D printed casing. Main results. We demonstrate the effectiveness of the OptoZIF Drive by performing real time optogenetic feedback in behaving mice. A novel feature of the OptoZIF Drive is its vertical circuit board, which facilities direct ZIF-clip connection. This feature requires angled insertion of an optical fiber that still can exit the drive from the center of a ring of recording electrodes. We designed an innovative 2-part protective shell that can be installed during the implant surgery to facilitate making additional connections to the circuit board. We use this feature to show that facial EMG in mice can be used as a control signal to lock stimulation to the animal’s motion, with stable EMG signal over several months. To decrease assembly time, reduce assembly errors, and improve repeatability, we fabricate assembly aids including a drive holder, a drill guide, an implant fixture for microelectode ‘pinning’, and a gold plating fixture. Significance. The

  15. MiBoard: Multiplayer Interactive Board Game

    CERN Document Server

    Dempsey, Kyle B; Jackson, G Tanner; Boonthum, Chutima; Levinstein, Irwin B; McNamara, Danielle S

    2010-01-01

    Serious games have recently emerged as an avenue for curriculum delivery. Serious games incorporate motivation and entertainment while providing pointed curriculum for the user. This paper presents a serious game, called MiBoard, currently being developed from the iSTART Intelligent Tutoring System. MiBoard incorporates a multiplayer interaction that iSTART was previously unable to provide. This multiplayer interaction produces a wide variation across game trials, while also increasing the repeat playability for users. This paper presents a demonstration of the MiBoard system and the expectations for its application.

  16. Hidden circuits and argumentation

    Science.gov (United States)

    Leinonen, Risto; Kesonen, Mikko H. P.; Hirvonen, Pekka E.

    2016-11-01

    Despite the relevance of DC circuits in everyday life and schools, they have been shown to cause numerous learning difficulties at various school levels. In the course of this article, we present a flexible method for teaching DC circuits at lower secondary level. The method is labelled as hidden circuits, and the essential idea underlying hidden circuits is in hiding the actual wiring of DC circuits, but to make their behaviour evident for pupils. Pupils are expected to find out the wiring of the circuit which should enhance their learning of DC circuits. We present two possible ways to utilise hidden circuits in a classroom. First, they can be used to test and enhance pupils’ conceptual understanding when pupils are expected to find out which one of the offered circuit diagram options corresponds to the actual circuit shown. This method aims to get pupils to evaluate the circuits holistically rather than locally, and as a part of that aim this method highlights any learning difficulties of pupils. Second, hidden circuits can be used to enhance pupils’ argumentation skills with the aid of argumentation sheet that illustrates the main elements of an argument. Based on the findings from our co-operating teachers and our own experiences, hidden circuits offer a flexible and motivating way to supplement teaching of DC circuits.

  17. Circuit reactivation dynamically regulates synaptic plasticity in neocortex

    Science.gov (United States)

    Kruskal, Peter B.; Li, Lucy; Maclean, Jason N.

    2013-10-01

    Circuit reactivations involve a stereotyped sequence of neuronal firing and have been behaviourally linked to memory consolidation. Here we use multiphoton imaging and patch-clamp recording, and observe sparse and stereotyped circuit reactivations that correspond to UP states within active neurons. To evaluate the effect of the circuit on synaptic plasticity, we trigger a single spike-timing-dependent plasticity (STDP) pairing once per circuit reactivation. The pairings reliably fall within a particular epoch of the circuit sequence and result in long-term potentiation. During reactivation, the amplitude of plasticity significantly correlates with the preceding 20-25 ms of membrane depolarization rather than the depolarization at the time of pairing. This circuit-dependent plasticity provides a natural constraint on synaptic potentiation, regulating the inherent instability of STDP in an assembly phase-sequence model. Subthreshold voltage during endogenous circuit reactivations provides a critical informative context for plasticity and facilitates the stable consolidation of a spatiotemporal sequence.

  18. The circuit designer's companion

    CERN Document Server

    Williams, Tim

    2013-01-01

    The Circuit Designer's Companion covers the theoretical aspects and practices in analogue and digital circuit design. Electronic circuit design involves designing a circuit that will fulfill its specified function and designing the same circuit so that every production model of it will fulfill its specified function, and no other undesired and unspecified function.This book is composed of nine chapters and starts with a review of the concept of grounding, wiring, and printed circuits. The subsequent chapters deal with the passive and active components of circuitry design. These topics are foll

  19. Intuitive analog circuit design

    CERN Document Server

    Thompson, Marc

    2013-01-01

    Intuitive Analog Circuit Design outlines ways of thinking about analog circuits and systems that let you develop a feel for what a good, working analog circuit design should be. This book reflects author Marc Thompson's 30 years of experience designing analog and power electronics circuits and teaching graduate-level analog circuit design, and is the ideal reference for anyone who needs a straightforward introduction to the subject. In this book, Dr. Thompson describes intuitive and ""back-of-the-envelope"" techniques for designing and analyzing analog circuits, including transistor amplifi

  20. Attachment method for stacked integrated circuit (IC) chips

    Energy Technology Data Exchange (ETDEWEB)

    Bernhardt, Anthony F. (Berkeley, CA); Malba, Vincent (Livermore, CA)

    1999-01-01

    An attachment method for stacked integrated circuit (IC) chips. The method involves connecting stacked chips, such as DRAM memory chips, to each other and/or to a circuit board. Pads on the individual chips are rerouted to form pads on the side of the chip, after which the chips are stacked on top of each other whereby desired interconnections to other chips or a circuit board can be accomplished via the side-located pads. The pads on the side of a chip are connected to metal lines on a flexible plastic tape (flex) by anisotropically conductive adhesive (ACA). Metal lines on the flex are likewise connected to other pads on chips and/or to pads on a circuit board. In the case of a stack of DRAM chips, pads to corresponding address lines on the various chips may be connected to the same metal line on the flex to form an address bus. This method has the advantage of reducing the number of connections required to be made to the circuit board due to bussing; the flex can accommodate dimensional variation in the alignment of chips in the stack; bonding of the ACA is accomplished at low temperature and is otherwise simpler and less expensive than solder bonding; chips can be bonded to the ACA all at once if the sides of the chips are substantially coplanar, as in the case for stacks of identical chips, such as DRAM.

  1. Attachment method for stacked integrated circuit (IC) chips

    Energy Technology Data Exchange (ETDEWEB)

    Bernhardt, A.F.; Malba, V.

    1999-08-03

    An attachment method for stacked integrated circuit (IC) chips is disclosed. The method involves connecting stacked chips, such as DRAM memory chips, to each other and/or to a circuit board. Pads on the individual chips are rerouted to form pads on the side of the chip, after which the chips are stacked on top of each other whereby desired interconnections to other chips or a circuit board can be accomplished via the side-located pads. The pads on the side of a chip are connected to metal lines on a flexible plastic tape (flex) by anisotropically conductive adhesive (ACA). Metal lines on the flex are likewise connected to other pads on chips and/or to pads on a circuit board. In the case of a stack of DRAM chips, pads to corresponding address lines on the various chips may be connected to the same metal line on the flex to form an address bus. This method has the advantage of reducing the number of connections required to be made to the circuit board due to bussing; the flex can accommodate dimensional variation in the alignment of chips in the stack; bonding of the ACA is accomplished at low temperature and is otherwise simpler and less expensive than solder bonding; chips can be bonded to the ACA all at once if the sides of the chips are substantially coplanar, as in the case for stacks of identical chips, such as DRAM. 12 figs.

  2. Circuit bridging of components by smoke

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.J.; Nowlen, S.P.; Anderson, D.J. [Sandia National Labs., Albuquerque, NM (United States)

    1996-10-01

    Smoke can adversely affect digital electronics; in the short term, it can lead to circuit bridging and in the long term to corrosion of metal parts. This report is a summary of the work to date and component-level tests by Sandia National Laboratories for the Nuclear Regulatory Commission to determine the impact of smoke on digital instrumentation and control equipment. The component tests focused on short-term effects such as circuit bridging in typical components and the factors that can influence how much the smoke will affect them. These factors include the component technology and packaging, physical board protection, and environmental conditions such as the amount of smoke, temperature of burn, and humidity level. The likelihood of circuit bridging was tested by measuring leakage currents and converting those currents to resistance in ohms. Hermetically sealed ceramic packages were more resistant to smoke than plastic packages. Coating the boards with an acrylic spray provided some protection against circuit bridging. The smoke generation factors that affect the resistance the most are humidity, fuel level, and burn temperature. The use of CO{sub 2} as a fire suppressant, the presence of galvanic metal, and the presence of PVC did not significantly affect the outcome of these results.

  3. Evaluating print performance of Sn-Ag-Cu lead-free solder pastes used in electronics assembly process

    Science.gov (United States)

    Mallik, S.; Bauer, R.; Hübner, F.; Ekere, N. N.

    2011-01-01

    Solder paste is the most widely used interconnection material in the electronic assembly process for attaching electronic components/devices directly onto the surface of printed circuit boards, using stencil printing process. This paper evaluates the performance of three different commercially available Sn-Ag-Cu solder pastes formulated with different particle size distributions (PSD), metal content and alloy composition. A series of stencil printing tests were carried out using a specially designed stencil of 75 μm thickness and apertures of 300×300 μm2 dimension and 500 μm pitch sizes. Solder paste printing behaviors were found related to attributes such as slumping and surface tension and printing performance was correlated with metal content and PSD. The results of the study should benefit paste manufacturers and SMT assemblers to improve their products and practices.

  4. Electrical Circuits and Water Analogies

    Science.gov (United States)

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  5. Circuit design techniques for non-crystalline semiconductors

    CERN Document Server

    Sambandan, Sanjiv

    2012-01-01

    Despite significant progress in materials and fabrication technologies related to non-crystalline semiconductors, fundamental drawbacks continue to limit real-world application of these devices in electronic circuits. To help readers deal with problems such as low mobility and intrinsic time variant behavior, Circuit Design Techniques for Non-Crystalline Semiconductors outlines a systematic design approach, including circuit theory, enabling users to synthesize circuits without worrying about the details of device physics. This book: Offers examples of how self-assembly can be used as a powerf

  6. 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....

  7. Electric circuits essentials

    CERN Document Server

    REA, Editors of

    2012-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Electric Circuits I includes units, notation, resistive circuits, experimental laws, transient circuits, network theorems, techniques of circuit analysis, sinusoidal analysis, polyph

  8. Detection of transient disturbing signals on PC boards

    Directory of Open Access Journals (Sweden)

    S. Korte

    2008-05-01

    Full Text Available This paper shows a possibility to visualize signal propagation in electronic circuits. Instead of using various galvanic measurement points all over the circuit, a test method is shown which measures the radiated field of the printed circuit board. By use of a 2-dimensional positionable field probe it is possible to get an overview over the signals running on the different parts of the PCB. In order to measure transient disturbing signals and distinguish them from normal device operation, problems of probe design and triggering need to be discussed.

  9. Load testing circuit

    DEFF Research Database (Denmark)

    2009-01-01

    A load testing circuit a circuit tests the load impedance of a load connected to an amplifier. The load impedance includes a first terminal and a second terminal, the load testing circuit comprising a signal generator providing a test signal of a defined bandwidth to the first terminal of the load...

  10. Short-circuit logic

    NARCIS (Netherlands)

    Bergstra, J.A.; Ponse, A.

    2010-01-01

    Short-circuit evaluation denotes the semantics of propositional connectives in which the second argument is only evaluated if the first argument does not suffice to determine the value of the expression. In programming, short-circuit evaluation is widely used. A short-circuit logic is a variant of p

  11. Piezoelectric drive circuit

    Science.gov (United States)

    Treu, Jr., Charles A.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes.

  12. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, Simon Minze; Vertregt, Maarten

    2011-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converte

  13. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, Simon Minze; Vertregt, Maarten

    2010-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converte

  14. Analysis of Multilayered Printed Circuit Boards using Computed Tomography

    Science.gov (United States)

    2014-05-01

    resistors harder to identify as Carbon is lower in the periodic table than Aluminium Oxide . Sample 2: Colour Bar Appendix D.2...Aluminium Al2O3 Aluminium Oxide BGA Ball Grid Array Coronal XZ Plane COTS Commercial Off The Shelf C Carbon CT Computed Tomography DC Direct Current...encapsulated in steel housing. Red Circle: Thin film resistors harder to identify as Carbon is lower in the periodic table than Aluminium Oxide . Sample 2

  15. Printed Circuit Board Integrated Toroidal Radio Frequency Inductors

    DEFF Research Database (Denmark)

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

    2012-01-01

    Modern power semiconductors allow for switching frequencies of power converters in the very high frequency (VHF) band (30 MHz to 300 MHz). The major advantage of this frequency increase is a remarkable reduction of the size of power converters due to smaller passive components. However crucial...... attention needs to be payed to switching losses, so that the size reduction in electrical components does not get consumed by a major increase in heatsink size. This paper is investigating the major size limiting component in power converters: the inductor. In the VHF range, inductors are typically...

  16. Advances in Integrated Heat Pipe Technology for Printed Circuit Boards

    NARCIS (Netherlands)

    Wits, Wessel W.; Riele, te Gert Jan

    2010-01-01

    Designing thermal control systems for electronic products has become very challenging due to the continuous miniaturization and increasing performance demands. Two-phase cooling solutions, such as heat pipes or vapor chambers, are increasingly used as they offer higher thermal coefficients for heat

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

    OpenAIRE

    Hellington Bastos da Silva de Sant’ana; Francisco José Moura; Hugo Marcelo Veit

    2015-01-01

    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, ...

  18. 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.

  19. Sequence assembly

    DEFF Research Database (Denmark)

    Scheibye-Alsing, Karsten; Hoffmann, S.; Frankel, Annett Maria

    2009-01-01

    Despite the rapidly increasing number of sequenced and re-sequenced genomes, many issues regarding the computational assembly of large-scale sequencing data have remain unresolved. Computational assembly is crucial in large genome projects as well for the evolving high-throughput technologies and...... in genomic DNA, highly expressed genes and alternative transcripts in EST sequences. We summarize existing comparisons of different assemblers and provide a detailed descriptions and directions for download of assembly programs at: http://genome.ku.dk/resources/assembly/methods.html....

  20. Reversible Logic Circuit Synthesis

    CERN Document Server

    Shende, V V; Markov, I L; Prasad, A K; Hayes, John P.; Markov, Igor L.; Prasad, Aditya K.; Shende, Vivek V.

    2002-01-01

    Reversible, or information-lossless, circuits have applications in digital signal processing, communication, computer graphics and cryptography. They are also a fundamental requirement for quantum computation. We investigate the synthesis of reversible circuits that employ a minimum number of gates and contain no redundant input-output line-pairs (temporary storage channels). We propose new constructions for reversible circuits composed of NOT, Controlled-NOT, and TOFFOLI gates (the CNT gate library) based on permutation theory. A new algorithm is given to synthesize optimal reversible circuits using an arbitrary gate library. We also describe much faster heuristic algorithms. We also pursue applications of the proposed techniques to the synthesis of quantum circuits.

  1. Tertiary activated carbon treatment of paper and board industry wastewater

    NARCIS (Netherlands)

    Temmink, B.G.; Grolle, K.C.F.

    2005-01-01

    The feasibility of activated carbon post-treatment of (biologically treated) wastewater from the paper and board industry was investigated, the goal being to remove refractory organic pollutants and produce water that can be re-used in the production process. Because closing water-circuits in the pa

  2. Feedback in analog circuits

    CERN Document Server

    Ochoa, Agustin

    2016-01-01

    This book describes a consistent and direct methodology to the analysis and design of analog circuits with particular application to circuits containing feedback. The analysis and design of circuits containing feedback is generally presented by either following a series of examples where each circuit is simplified through the use of insight or experience (someone else’s), or a complete nodal-matrix analysis generating lots of algebra. Neither of these approaches leads to gaining insight into the design process easily. The author develops a systematic approach to circuit analysis, the Driving Point Impedance and Signal Flow Graphs (DPI/SFG) method that does not require a-priori insight to the circuit being considered and results in factored analysis supporting the design function. This approach enables designers to account fully for loading and the bi-directional nature of elements both in the feedback path and in the amplifier itself, properties many times assumed negligible and ignored. Feedback circuits a...

  3. Exact Threshold Circuits

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Podolskii, Vladimir V.

    2010-01-01

    We initiate a systematic study of constant depth Boolean circuits built using exact threshold gates. We consider both unweighted and weighted exact threshold gates and introduce corresponding circuit classes. We next show that this gives a hierarchy of classes that seamlessly interleave with the ......We initiate a systematic study of constant depth Boolean circuits built using exact threshold gates. We consider both unweighted and weighted exact threshold gates and introduce corresponding circuit classes. We next show that this gives a hierarchy of classes that seamlessly interleave...... with the well-studied corresponding hierarchies defined using ordinary threshold gates. A major open problem in Boolean circuit complexity is to provide an explicit super-polynomial lower bound for depth two threshold circuits. We identify the class of depth two exact threshold circuits as a natural subclass...

  4. Building better boards.

    Science.gov (United States)

    Nadler, David A

    2004-05-01

    Companies facing new requirements for governance are scrambling to buttress financial-reporting systems, overhaul board structures--whatever it takes to comply. But there are limits to how much good governance can be imposed from the outside. Boards know what they ought to be: seats of challenge and inquiry that add value without meddling and make CEOs more effective but not all-powerful. A board can reach that goal only if it functions as a high-performance team, one that is competent, coordinated, collegial, and focused on an unambiguous goal. Such entities don't just evolve; they must be constructed to an exacting blueprint--what the author calls board building. In this article, Nadler offers an agenda and a set of tools that boards can use to define and achieve their objectives. It's important for a board to conduct regular self-assessments and to pay attention to the results of those analyses. As a first step, the directors and the CEO should agree on which of the following common board models best fits the company: passive, certifying, engaged, intervening, or operating. The directors and the CEO should then analyze which business tasks are most important and allot sufficient time and resources to them. Next, the board should take inventory of each director's strengths to ensure that the group as a whole possesses the skills necessary to do its work. Directors must exert more influence over meeting agendas and make sure they have the right information at the right time and in the right format to perform their duties. Finally, the board needs to foster an engaged culture characterized by candor and a willingness to challenge. An ambitious board-building process, devised and endorsed both by directors and by management, can potentially turn a good board into a great one.

  5. Ordinary General Assembly

    CERN Multimedia

    Staff Association

    2010-01-01

    Tuesday 20 April at 10.00 Council Chamber, Bldg 503 In conformity with the Statutes of the Staff Association, an ordinary General Assembly is organized once a year (article IV.2.1). Agenda   Adoption of the Agenda Approval of the Draft Minutes of the Ordinary General Assembly of 12 May 2009 Presentation and approval of the Activity Report 2009 Presentation and approval of the Financial Report 2009 Presentation and approval of the Auditors Report 2009 Programme for 2010 Presentation et and approval of the draft budget and subscription rate 2010 Election of the Election Committee Election of the Board of Auditors Miscellaneous We remind members of article IV.3.4 in the Statutes of the Association which reads: “After having dealt with all the items on the agenda, the members may, with the consent of the Assembly, have other matters discussed, but decisions may be taken only on the items listed on the agenda. Nevertheless, the Assembly may require t...

  6. Ordinary General Assembly

    CERN Multimedia

    Staff Association

    2011-01-01

    Tuesday 12 April at 14.00 Council Chamber, Bldg 503 In conformity with the Statutes of the Staff Association, an ordinary General Assembly is organized once a year (article IV.2.1). Agenda   Adoption of the Agenda Approval of the Draft Minutes of the Ordinary General Assembly of 20 April 2010 Presentation and approval of the Activity Report 2010 Presentation and approval of the Financial Report 2010 Presentation and approval of the Auditors Report 2010 Programme for 2011 Presentation et and approval of the draft budget and subscription rate 2012 Election of the Election Committee Election of the Board of Auditors Miscellaneous We remind members of article IV.3.4 in the Statutes of the Association which reads: “After having dealt with all the items on the agenda, the members may, with the consent of the Assembly, have other matters discussed, but decisions may be taken only on the items listed on the agenda. Nevertheless, the Assembly ma...

  7. Ordinary General Assembly

    CERN Multimedia

    Staff Association

    2011-01-01

    Tuesday 12 April at 14.00 Council Chamber, Bldg 503 In conformity with the Statutes of the Staff Association, an ordinary General Assembly is organized once a year (article IV.2.1). Agenda   Adoption of the Agenda Approval of the Draft Minutes of the Ordinary General Assembly of 20 April 2010 Presentation and approval of the Activity Report 2010 Presentation and approval of the Financial Report 2010 Presentation and approval of the Auditors Report 2010 Programme for 2011 Presentation and approval of the draft budget and subscription rate 2012 Election of the Election Committee Election of the Board of Auditors Miscellaneous We remind members of article IV.3.4 in the Statutes of the Association which reads: “After having dealt with all the items on the agenda, the members may, with the consent of the Assembly, have other matters discussed, but decisions may be taken only on the items listed on the agenda. Nevertheless, the Assembly may r...

  8. 低温碱性熔炼分离提取废弃电路板粉末中两性金属%Separation and extraction of amphoteric metals from waste printed circuit board powders by low-temperature alkaline smelting

    Institute of Scientific and Technical Information of China (English)

    刘静欣; 郭学益; 田庆华; 李栋

    2014-01-01

    模拟废弃电路板破碎、分选后得到的多金属富集粉末,通过单因素实验和正交试验,采用低温碱性熔炼研究熔炼温度、熔炼时间和盐料质量比对其中有价金属分离提取率的影响.结果表明,最佳条件为熔炼温度400℃,熔炼时间1.5 h,盐料质量比3.5,其中盐料质量比对两性金属提取率影响最显著.在最佳条件下,两性金属提取率为 Sn 83.6%、Al 92.7%、Zn 80.9%及Sb 34.5%,以可溶盐形式富集在浸出液中,铜等其他成分则于渣中富集,有效实现了两性金属与其他金属的分离.%Multi-component metal powders were prepared by imitating the crushed metal enrichment originated from waste printed circuit boards. The effects of smelting temperature, smelting time and NaNO3-NaOH/powder mass ratio on the extracting ratios of am-photeric metals during low-temperature alkaline smelting were investigated through single-factor experiments and orthogonal tests. It is found that the mass ratio of NaNO3-NaOH to crushed metal enrichment has the most significant effect on the extracting ratios of ampho-teric metals. The optimum conditions were obtained as the smelting temperature of 400℃, the smelting time of 1. 5 h and the mass ratio of NaNO3-NaOH to crushed metal enrichment of 3. 5. Under the optimum conditions, the extracting ratios of amphoteric metals are as the following:Sn 83. 6%, Al 92. 7%, Zn 80. 9%, and Sb 34. 5%. Amphoteric metals are converted to sodium salts, dissolving in the leaching process, while other components, such as copper and precious metals, are enriched in the residue. In this novel process, am-photeric metals are separated with other metals efficiently.

  9. 无电镀镍浸金处理电路板在 NaHSO3溶液中的腐蚀电化学行为与失效机制%Corrosion behavior and failure mechanism of electroless nickel immersion gold processing circuit boards in NaHSO3 electrolyte solution

    Institute of Scientific and Technical Information of China (English)

    丁康康; 李晓刚; 董超芳; 易盼; 刘明; 肖葵

    2015-01-01

    采用交流阻抗谱研究了无电镀镍浸金处理电路板在模拟电解质溶液(0.1 mol·L-1 NaHSO3)中的电化学腐蚀行为,并结合体视学显微镜、扫描电镜、X射线能谱分析等手段分析了试样表面腐蚀产物形貌、组成和镀层失效机制.无电镀镍浸金处理电路板在NaHSO3溶液中的耐蚀性较差,浸泡12 h试样表面局部即发生变色,伴随有微裂纹的产生.电解液能够通过裂纹直接侵蚀Cu基底,并在微裂纹周围生成较多的枝晶状结晶产物,其主要组分为Cu2 S.该结晶腐蚀产物的不断生成使局部区域中间Ni过渡层与Cu基底结合部位存在较大的横向剪切应力,最终造成Ni镀层的脱离与鼓泡现象.%ABSTRACT Electrochemical impedance spectroscopy ( EIS) was used to study the corrosion behavior of electroless nickel immer-sion gold processing printed circuit boards (PCB- ENIG) in a simulated electrolyte solution (0.1 mol·L-1 NaHSO3), and the mor-phology, composition of corrosion products as well as the failure mechanism of the plating layer were analyzed with the aid of stereo mi-croscopy and scanning electron microscopy ( SEM) combined with energy dispersive spectrometry ( EDS) . It is found that the corro-sion resistance of PCB-ENIG in NaHSO3 solution is relative poor. Partial discolor appears in PCB- ENIG just immersing for 12 h, along with micro-crack generation. The electrolyte can directly erode the Cu substrate through micro-cracks, forming dendritic crystal-line products around these micro-cracks, whose main composition should be Cu2 S. Continuous generation of these corrosion products results in large transverse shear stress between the Ni intermediate layer and Cu substrate, and eventually bubbling and shedding of the Ni plating layer occur.

  10. SMART Boards Rock

    Science.gov (United States)

    Giles, Rebecca M.; Shaw, Edward L.

    2011-01-01

    SMART Board is a technology that combines the functionality of a whiteboard, computer, and projector into a single system. The interactive nature of the SMART Board offers many practical uses for providing an introduction to or review of material, while the large work area invites collaboration through social interaction and communication. As a…

  11. Evaluate Your Board.

    Science.gov (United States)

    Heck, Glenn

    1982-01-01

    A checklist can be used to evaluate a school board's current level of performance as either "adequate" or "needs improvement." The areas covered include goal setting, policy, finance, relationships with the superintendent, community relations, board meetings, staff and personnel relationships, instructional programs, leadership, energy…

  12. Embracing an International Board

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A new international stock board will soon be established in Shanghai,allowing foreign companies to list their businesses and tap into the China market China is moving closer to launching its own international stock board,a market for foreign companies to list their stocks in China,said Shang Fulin,

  13. Microfluidic technologies for studying synthetic circuits.

    Science.gov (United States)

    Lin, Benjamin; Levchenko, Andre

    2012-08-01

    Advances in synthetic biology have augmented the available toolkit of biomolecular modules, allowing engineering and manipulation of signaling in a variety of organisms, ranging in complexity from single bacteria and eukaryotic cells to multi-cellular systems. The richness of synthetic circuit outputs can be dramatically enhanced by sophisticated environmental control systems designed to precisely pattern spatial-temporally heterogeneous environmental stimuli controlling these circuits. Moreover, the performance of the synthetic modules and 'blocks' needed to assemble more complicated networks requires more complete characterization as a function of arbitrarily complex environmental inputs. Microfluidic technologies are poised to meet these needs through a variety of innovative designs capitalizing on the unique benefits of manipulating fluids on the micro-scales and nano-scales. This review discusses the utility of microfluidics for the study of synthetic circuits and highlights recent work in the area.

  14. Board of Education, Island Trees Union Free School District No. 26 et al., Petitioners, v. Steven A. Pico, by His Next Friend, Frances Pico et al. On Writ of Certiorari to the United States Court of Appeals for the Second Circuit. Supreme Court of the United States, No. 80-2043.

    Science.gov (United States)

    Supreme Court of the U. S., Washington, DC.

    The Supreme Court decision in the case of the Board of Education, Island Trees, New York, versus Steven A. Pico, addressed whether the First Amendment imposes limitations upon the exercise by a local school board of its discretion to remove library books from high school and junior high school libraries. Rejecting the recommendations of a…

  15. The Versatile Link Demo Board (VLDB)

    Science.gov (United States)

    Martín Lesma, R.; Alessio, F.; Barbosa, J.; Baron, S.; Caplan, C.; Leitao, P.; Pecoraro, C.; Porret, D.; Wyllie, K.

    2017-02-01

    The Versatile Link Demonstrator Board (VLDB) is the evaluation kit for the radiation-hard Optical Link ecosystem, which provides a 4.8 Gbps data transfer link for communication between front-end (FE) and back-end (BE) of the High Energy Physics experiments. It gathers the Versatile link main radiation-hard custom Application-Specific Integrated Circuits (ASICs) and modules: GBTx, GBT-SCA and VTRx/VTTx plus the FeastMP, a radiation-hard in-house designed DC-DC converter. This board is the first design allowing system-level tests of the Link with a complete interconnection of the constitutive components, allowing data acquisition, control and monitoring of FE devices with the GBT-SCA pair.

  16. Analog circuit design

    CERN Document Server

    Dobkin, Bob

    2012-01-01

    Analog circuit and system design today is more essential than ever before. With the growth of digital systems, wireless communications, complex industrial and automotive systems, designers are being challenged to develop sophisticated analog solutions. This comprehensive source book of circuit design solutions aids engineers with elegant and practical design techniques that focus on common analog challenges. The book's in-depth application examples provide insight into circuit design and application solutions that you can apply in today's demanding designs. <

  17. Parallelizing quantum circuit synthesis

    OpenAIRE

    Di Matteo, Olivia; Mosca, Michele

    2016-01-01

    Quantum circuit synthesis is the process in which an arbitrary unitary operation is decomposed into a sequence of gates from a universal set, typically one which a quantum computer can implement both efficiently and fault-tolerantly. As physical implementations of quantum computers improve, the need is growing for tools which can effectively synthesize components of the circuits and algorithms they will run. Existing algorithms for exact, multi-qubit circuit synthesis scale exponentially in t...

  18. Regenerative feedback resonant circuit

    Science.gov (United States)

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  19. Analog circuits cookbook

    CERN Document Server

    Hickman, Ian

    2013-01-01

    Analog Circuits Cookbook presents articles about advanced circuit techniques, components and concepts, useful IC for analog signal processing in the audio range, direct digital synthesis, and ingenious video op-amp. The book also includes articles about amplitude measurements on RF signals, linear optical imager, power supplies and devices, and RF circuits and techniques. Professionals and students of electrical engineering will find the book informative and useful.

  20. A Motor Drive Electronics Assembly for Mars Curiosity Rover: An Example of Assembly Qualification for Extreme Environments

    Science.gov (United States)

    Kolawa, Elizabeth; Chen, Yuan; Mojarradi, Mohammad M.; Weber, Carissa Tudryn; Hunter, Don J.

    2013-01-01

    This paper describes the technology development and infusion of a motor drive electronics assembly for Mars Curiosity Rover under space extreme environments. The technology evaluation and qualification as well as space qualification of the assembly are detailed and summarized. Because of the uncertainty of the technologies operating under the extreme space environments and that a high level reliability was required for this assembly application, both component and assembly board level qualifications were performed.

  1. Timergenerator circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Timer/Generator Circuits Manual is an 11-chapter text that deals mainly with waveform generator techniques and circuits. Each chapter starts with an explanation of the basic principles of its subject followed by a wide range of practical circuit designs. This work presents a total of over 300 practical circuits, diagrams, and tables.Chapter 1 outlines the basic principles and the different types of generator. Chapters 2 to 9 deal with a specific type of waveform generator, including sine, square, triangular, sawtooth, and special waveform generators pulse. These chapters also include pulse gen

  2. CMOS circuits manual

    CERN Document Server

    Marston, R M

    1995-01-01

    CMOS Circuits Manual is a user's guide for CMOS. The book emphasizes the practical aspects of CMOS and provides circuits, tables, and graphs to further relate the fundamentals with the applications. The text first discusses the basic principles and characteristics of the CMOS devices. The succeeding chapters detail the types of CMOS IC, including simple inverter, gate and logic ICs and circuits, and complex counters and decoders. The last chapter presents a miscellaneous collection of two dozen useful CMOS circuits. The book will be useful to researchers and professionals who employ CMOS circu

  3. Electronic devices and circuits

    CERN Document Server

    Pridham, Gordon John

    1968-01-01

    Electronic Devices and Circuits, Volume 1 deals with the design and applications of electronic devices and circuits such as passive components, diodes, triodes and transistors, rectification and power supplies, amplifying circuits, electronic instruments, and oscillators. These topics are supported with introductory network theory and physics. This volume is comprised of nine chapters and begins by explaining the operation of resistive, inductive, and capacitive elements in direct and alternating current circuits. The theory for some of the expressions quoted in later chapters is presented. Th

  4. 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

  5. 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

  6. Security electronics circuits manual

    CERN Document Server

    MARSTON, R M

    1998-01-01

    Security Electronics Circuits Manual is an invaluable guide for engineers and technicians in the security industry. It will also prove to be a useful guide for students and experimenters, as well as providing experienced amateurs and DIY enthusiasts with numerous ideas to protect their homes, businesses and properties.As with all Ray Marston's Circuits Manuals, the style is easy-to-read and non-mathematical, with the emphasis firmly on practical applications, circuits and design ideas. The ICs and other devices used in the practical circuits are modestly priced and readily available ty

  7. Decamp Clock Board Firmware

    Energy Technology Data Exchange (ETDEWEB)

    Vicente, J. de; Castilla, J.; Martinez, G.

    2007-09-27

    Decamp (Dark Energy Survey Camera) is a new instrument designed to explore the universe aiming to reveal the nature of Dark Energy. The camera consists of 72 CCDs and 520 Mpixels. The readout electronics of DECam is based on the Monsoon system. Monsoon is a new image acquisition system developed by the NOAO (National Optical Astronomical Observatory) for the new generation of astronomical cameras. The Monsoon system uses three types of boards inserted in a Eurocard format based crate: master control board, acquisition board and clock board. The direct use of the Monsoon system for DECam readout electronics requires nine crates mainly due to the high number of clock boards needed. Unfortunately, the available space for DECam electronics is constrained to four crates at maximum. The major drawback to achieve such desired compaction degree resides in the clock board signal density. This document describes the changes performed at CIEMAT on the programmable logic of the Monsoon clock board aiming to meet such restricted space constraints. (Author) 5 refs.

  8. JOINT ADVISORY APPEALS BOARD

    CERN Multimedia

    Human Resources Division

    2002-01-01

    The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Serge Peraire with regard to exceptional advancement. As the appellant has not objected, the report of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 17 to 31 May 2002. Human Resources Division Tel. 74128

  9. Joint Advisory Appeals Board

    CERN Multimedia

    2003-01-01

    The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mrs Judith Igo-Kemenes concerning the application of procedures foreseen by Administrative Circular N§ 26 (Rev. 3). As the appellant has not objected, the report of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 6 to 20 June 2003. Human Resources Division Tel. 74128

  10. Joint Advisory Appeals Board

    CERN Multimedia

    2004-01-01

    The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mrs Maria DIMOU with regard to a periodic one-step increase. As the appellant has not objected, the report of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 30 April to 14 May 2004. Human Resources Department Tel. 74128

  11. Joint Advisory Appeals Board

    CERN Multimedia

    2003-01-01

    The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Aloïs Girardoz with regard to classification and advancement. As the appellant has not objected, the Board's report and the Director-General's decision will be brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 15 to 29 August 2003. Human Resources Division Tel. 74128

  12. JOINT ADVISORY APPEALS BOARD

    CERN Multimedia

    Human Resources Division

    2002-01-01

    The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Bertrand Nicquevert with regard to the non-resident allowance. As the appellant has not objected, the report of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 29 November to 13 December 2002. Human Resources Division Tel. 74128

  13. JOINT ADVISORY APPEALS BOARD

    CERN Multimedia

    Human Resources Division

    2002-01-01

    The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Jack Blanchard with regard to 'non recognition of specific functions'. As the appellant has not objected, the report of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 12th to 26th April 2002. Human Resources Division Tel. 74128

  14. JOINT ADVISORY APPEALS BOARD

    CERN Multimedia

    Human Resources Division

    2002-01-01

    The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Antonio Millich with regard to advancement. As the appellant has not objected, the report of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 27 September to 11 October 2002. Human Resources Division Tel. 74128

  15. Joint Advisory Appeals Board

    CERN Multimedia

    2003-01-01

    The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Poul Frandsen concerning his assimilation into the new career structure. As the appellant has not objected, the report of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 13 to 24 January 2003. Human Resources Division Tel. 74128

  16. JOINT ADVISORY APPEALS BOARD

    CERN Multimedia

    Human Resources Division

    2002-01-01

    The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Luc Vos with regard to advancement. As the appellant has not objected, the report of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (N° 60) from 14 to 28 June 2002. Human Resources Division Tel. 74128

  17. JOINT ADVISORY APPEALS BOARD

    CERN Multimedia

    Personnel Division

    1999-01-01

    The Joint Advisory Appeals Board was convened to examine the appeal lodged by Mr Joào Bento with regard to residential category. As the appellant has not objected, the recommendations of the Board and the final decision of the Director-General are brought to the notice of the personnel in accordance with Article RÊVIÊ1.20 of the Staff Regulations.The relevant documents will therefore be posted on the notice boards of the Administration Building (N¡ 60) from 29 October to 12 November 1999.Personnel DivisionTel. 74128

  18. Joint Advisory Appeals Board

    CERN Multimedia

    HR Department

    2006-01-01

    The Joint Advisory Appeals Board was convened to examine an appeal lodged by a member of the personnel with regard to advancement. The person concerned has requested that the report of the Board and the final decision of the Director-General be brought to the notice of the personnel in accordance with Article R VI 1.20 of the Staff Regulations. The relevant documents will therefore be posted on the notice boards of the Administration Building (No. 60) from 24 March to 10 April 2006. Human Resources Department Tel. 74128

  19. Joint Advisory Appeals Board

    CERN Multimedia

    HR Department

    2008-01-01

    The Joint Advisory Appeals Board has examined the internal appeal lodged by a member of the personnel with regard to the decision not to award him a periodic one-step advancement for the 2006 reference year. The person concerned has not objected to the report of the Board and the final decision of the Director-General being brought to the notice of the members of the personnel. In application of Article R VI 1.18 of the Staff Regulations, these documents will therefore be posted on the notice board of the Main building (Bldg. 500) from 17 March to 30 March 2008. Human Resources Department Tel. 73911

  20. Joint Advisory Appeals Board

    CERN Multimedia

    HR Department

    2008-01-01

    The Joint Advisory Appeals Board has examined the internal appeal lodged by a member of the personnel against the decision to grant him only a periodic one-step advancement for the 2006 reference year. The person concerned has not objected to the report of the Board and the final decision of the Director-General being brought to the attention of the members of the personnel. In application of Article R VI 1.18 of the Staff Regulations, these documents will therefore be posted on the notice board of the Main Building (Bldg. 500) from 1 September to 14 September 2008. Human Resources Department (73911)