WorldWideScience

Sample records for ammeters

  1. The Moving-Coil Ammeter: Technical Terminology Bulletin. Terminotech, Vol. 2, No. 8.

    Science.gov (United States)

    General Electric Co. of Canada, Ltd., Montreal, Quebec.

    This issue of a bulletin of technological terminology is devoted to the moving-coil ammeter. A brief narrative on the subject is presented in both French and English. A English-French dictionary of terms comprises the bulk of the document. Explanatory illustrations are appended. (JB)

  2. 图尔克RFID系统在智能电表检测线中的应用%Application of TURCK RFID System in Intelligent Ammeter Test Production Line

    Institute of Scientific and Technical Information of China (English)

    只凯

    2016-01-01

    本文结合智能电表行业的发展现状,介绍了电表检测线和RFID技术,以及图尔克RFID系统在智能电表检测线中的应用。%Based on the development of intelligent ammeter industry, we mainly introduce the ammeter test production line, RFID technology and the application of TURCK RFID system in intelligent ammeter test production line.

  3. Talking about How to Improve Power Supply Enterprise ’s Working Efficiency of the Business Expanding and Ammeter Installing%提升供电业扩报装工作效率对策探讨

    Institute of Scientific and Technical Information of China (English)

    乔冬

    2014-01-01

    业扩报装是供电企业与电力客户建立供用电关系、供电企业为社会提供电力服务的重要环节。阐述了业扩报装工作的主要内容,分析了影响业扩报装工作效率的主要因素,探讨了优化业扩报装工作的主要流程,提出了提升业扩报装工作效率的举措。%The business expanding and ammeter installing is an important link for power supply enterprise to establish the power supply and demand relationship with power customers and provide electricity services for the society. This paper expounds the main contents of the work of business expanding and ammeter installing, analyzes some main factors influencing the working efficiency of the business expanding and ammeter installing, probes the main processes of optimizing the business expanding and ammeter installing, and puts forward some measures for improving the working efficiency of the business expanding and ammeter installing.

  4. 远程自动抄表系统及其效益分析%LONG-DISTANCE AUTOMATICAL COPY AMMETER DATA SYSTEM AND ITS BENEFICAL ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    覃达

    2000-01-01

    随着我国社会、经济的发展,居民用电越来越普及,且用电量日益剧增,传统的人工抄表收取电费方式,已经不能满足现代化管理的要求。为此,我们根据远程数据通信与台区内载波通信联络相接合的技术原理,开发了远程自动抄表系统,该系统功能齐全,操作方便,安装简易。经过-年多的运行,系统工作稳定,计费及时、准确、可靠,产生了显著的经济效益。本文介绍系统的设计思想和系统各部分单元的工作原理及其技术性能和特点。%With social economic develop ment electric power is used by dwellers popularly and the amount of electric power is used increasingly. Traditional charge of electric fare by manual labour can't satisfy the demand for modem managrnent. Thus according to teachnical principle of jointing teledata communications with station carrier wave liaison, we had devised long-distance automatic copy ammeter data system. This system function is complete, its operation is convenient, and its install ment is facile. After one year operation, the system' s steady, the counting is in time with credibility, bringing remarkable economical benefit. In this paper we introduce systematic designing idea and work principle of every unit and technical capability.

  5. 基于像素比例法和GA-BP的单相电表读数识别%Recognition of numeric characters on single-phase ammeter dial plate based on GA-BP and pixel-scale algorithms

    Institute of Scientific and Technical Information of China (English)

    冯冬青; 付巍; 石成辉

    2009-01-01

    对单相电表表盘读数的显示特点进行了研究,针对在电表表盘末位刻度识别中存在识别困难,识别率低的情况,提出了像素比例法这一精确识别方法.对初始图像采用大津二值化法,中值滤波法进行预处理,用投影法分别对字段及单个字符进行分割.采用GA-BP算法识别表盘读数.在样本集下单整字识别率为99.2%,非整字识别率为97.7%.实验结果表明,该方法对刻度有较高的识别精度.%The feature is researched, which numeric characters display on single-phase ammeter dial plate. Against the scale which is on the bottom of the ammeter dial plate is difficult to be recognized, and its recognition rate is very low, an algorithm based on Pixei-scale method is put forward. Otsu binary transform algorithm and mid-value filter method are used to preprocess the original image. Pro-jection algorithm is used to field a single character and the segmentation. GA-BP algorithm is introduced into precise automatic recognition of numeric characters on single-phase ammeter dial plate. The whole-word recognition rate reaches 99.2%, non-whole word recognition rate reaches 97.7%. Experiments show that the algorithm has more high precision.

  6. 47 CFR 73.57 - Remote reading antenna and common point ammeters.

    Science.gov (United States)

    2010-10-01

    ... current sensing device for providing direct current to indicating instrument. (4) Current transformer... into the excitation circuit feed line, which shall employ series tuning only (no shunt circuits of...

  7. Measuring Earth's Magnetic Field Simply.

    Science.gov (United States)

    Stewart, Gay B.

    2000-01-01

    Describes a method for measuring the earth's magnetic field using an empty toilet paper tube, copper wire, clear tape, a battery, a linear variable resistor, a small compass, cardboard, a protractor, and an ammeter. (WRM)

  8. Development of a trans-admittance mammography (TAM) using 60×60 electrode array

    Science.gov (United States)

    Zhao, Mingkang; Liu, Qin; In Oh, Tong; Woo, Eung Je; Seo, Jin Keun

    2010-04-01

    We have developed a trans-admittance mammography (TAM) system as a supplementary or alternative method of the X-ray mammography to diagnose the breast cancer. Mechanical structure of the system is similar to the X-ray mammography with the breast placed between two plates. The pair of plates is movable to accommodate breasts with different sizes and rotatable to provide multiple images with different projection angles. Without using ionizing radiation, it acquires a projection image of tissue admittivity values. One plate is a flat solid electrode where we apply a constant sinusoidal voltage with a variable frequency. The other is equipped with 60×60 array of current-sensing electrodes, of which potentials are kept at the signal reference level. The electrode array is connected to six switching modules and each module routes current signals from 600 electrodes to two ammeter modules. Each ammeter module includes six channels of ammeters and each one of them comprises an independent current-to-voltage converter, voltage amplifier, ADC and digital phase-sensitive demodulator. Each ammeter sequentially measures exit currents from 50 electrodes chosen by the corresponding switching module. An FPGA controls six ammeters to collect real- and imaginary-parts of trans-admittance data from 300 electrodes. A separate FPGA arbitrates data and command exchanges between a DSP-based main controller and ammeter modules. It also generates a sinusoidal voltage signal to be applied to the breast. All the 3600 complex current data from 12 ammeter modules are transferred to the main controller, which is interfaced to a PC through an isolated USB. The system is provided with a program to display real- and imaginary-parts of measured trans-admittance maps. The measured maps at multiple frequencies are incorporated into a frequency-difference anomaly detection algorithm. In this paper, we describe the design and construction of the system.

  9. Control of the Superconducting Magnets current Power Supplies of the TJ-II Gyrotrons; Control de las Fuentes de Corriente de las Bobinas Superconductoras de los Girotrones del TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Ros, A.; Fernandez, A.; Tolkachev, A.; Catalan, G.

    2006-07-01

    The TJ-II ECRH heating system consists of two gyrotrons, which can deliver a maximum power of 300 kW at a frequency of 53.2 GHz. Another 28 GHz gyrotron is going to be used in the Bernstein waves heating system. In order to get the required frequency, the gyrotrons need and homogeneous magnetic field of several tesla, which is generated by a superconducting coil field by a current source. This document describes the current source control as well as the high precision ammeters control. These ammeters measure the current in the superconducting coils. The user interface and the programming of the control system are described. The communication between devices is also explained. (author) 9 Refs.

  10. Energy balance in motor vehicles

    Science.gov (United States)

    Dziubńiski, M.; Drozd, A.; Adamiec, M.; Siemionek, E.

    2016-09-01

    This paper present the concept of testing energy balance. The test was conducted on the test bench equipped with the alternator, battery and standard mounted current receivers. The course of measurements consisted in recording the indications of three ammeters and a tachometer. On the basis of the recorded current values, it was possible to determine: energy received from the battery, consumed by the receivers and the energy drawn from the alternator.

  11. Motor Demonstration Using a Hand-Cranked Genecon

    Science.gov (United States)

    2014-10-01

    capacitor will make the motion of the motorized handle significantly faster than with the ammeter still in the circuit.) Show students that the direction...of rotation of the handle does not reverse even if you temporarily freeze the handle in Motor Demonstration Using a Hand- Cranked Genecon Carl E...turning as an electric motor . How does the current direction compare before and after you stop cranking the handle? How does the direction of the

  12. Development of an Ultralight Pulse Gas Metal ARC Welding System for Shipyard Applications

    Science.gov (United States)

    2007-07-27

    standard 200A OXO, Model AP20. Instrumentation included a calibrated analog ammeter (shunt, mV meter) and VOM (Simpson 260). Initial testing used...strength predicted based on the same correlation. In both cases, weld metal Charpy V-notch impact test results far exceeded minimum specification...Technology (CNST), work was conducted to specify, build, test , and production prove a light-weight, man-portable welding system as described above. The

  13. Introduction to electronics

    CERN Document Server

    Korneff, Theodore

    1966-01-01

    Introduction to Electronics focuses on the study of electronics and electronic devices. Composed of 14 chapters, the book starts with discussions on dc circuits, including resistance, voltmeter, ammeter, galvanometer, internal resistance, and positive and negative currents. This topic is followed by discussions on ac circuits, particularly addressing voltage and current, average power, resistive load, complex plane, and parallel circuits. Discussions also focus on filters and tuned circuits, diodes, and power supplies. Particularly given attention are the processes, diagrams, and analyses

  14. Effect of Temperature on the Galvanic Corrosion of Cu-Ni Alloy/High Strength Steel in Seawater

    Directory of Open Access Journals (Sweden)

    Wang Chun Li

    2016-01-01

    Full Text Available The galvanic corrosion behavior of Cu-Ni Alloy(B10/high strength steel (921A has been studied using a zero-resistance ammeter (ZRA in seawater at different temperatures. As well as it was systemically investigated by weight loss measurements, electrochemical methods and scanning electron microscope.Results showed 921A acts as the anode and B10 act as the cathodes. The effect of temperature on the galvanic corrosion is important, the corrosion rate became higher with the temperature increased.

  15. NMR Evidence for a Planar Arene Intermediate in the Electron-Transfer Induced Eta 6 to Eta 4 Hapticity Change of a Rhodium Arene Complex

    Science.gov (United States)

    1989-07-01

    complex. Elschenbroich and co-workers2 8 observed large differences in coupling constants for the protons of the bent benzene ring in the ESR spectrum...characterization by Elschenbroich , et al., of the bent arene 19-electron complex [(n4-C6H6 )Cr(C 6H6 )3- 28, it rust be considered that bent arene structures...Koelle, U.; Fuss, B.; Rajasekharan, M.V.; Ramakrishna, B.L. Ammeter, J.H.; Boehm, M.C. J. Amer. Chem. Soc., 1984, 206, 4152. 28. Elschenbroich , Ch

  16. Coating Prospects in Corrosion Prevention of Aluminized Steel and Its Coupling with Magnesium

    Science.gov (United States)

    Sun, Fuyan

    In this study, a plasma electrolytic oxidation (PEO) process was used to form oxide coating on aluminized steel, heated aluminized steel and magnesium. A potentiodynamic polarization corrosion test was employed to investigate the general corrosion properties. Galvanic corrosion of steel samples and magnesium samples was studied by zero resistance ammeter (ZRA) tests and boiling tests. Scanning electron microscopy (SEM) and EDS were used to investigate the coating microstructure and the coating/substrate interface. In general, the PEO coatings on all three substrate can help prevent general corrosion. 6-min coated magnesium with unipolar current mode performs best in most galvanic couplings for preventing both general corrosion and galvanic corrosion. Factors which could influence galvanic corrosion behaviors of tested samples were discussed based on area ratios of anode/cathode and cell potential driving force during the ZRA corrosion tests and boiling tests.

  17. High density trans-admittance mammography development and preliminary phantom tests

    Directory of Open Access Journals (Sweden)

    Zhao Mingkang

    2012-09-01

    Full Text Available Abstract Background Malignant breast tumor tissue has a significantly different electrical impedance spectrum than surrounding normal tissues. This has led to the development of impedance imaging as a supplementary or alternative method to X-ray mammography for screening and assessment of breast cancers. However low spatial resolution and poor signal to noise ratio has limited the clinical application. Methods In order to improve spatial resolution we developed a trans-admittance mammography (TAM system including an array of 60×60 current sensing electrodes. We adopted a similar setup to X-ray mammography where the breast is situated between two holding plates. The top plate is a large solid metal electrode for applying a sinusoidal voltage over a range of frequencies from 50 Hz to 500 kHz. The bottom plate has 3600 current sensing electrodes that are kept at the ground potential. Currents are generated from the top voltage-applying electrode and spread throughout the breast, entering the TAM system through the array of current sensing electrodes on the bottom plate. The TAM system measures the exit currents through 6 switching modules connected to 600 electrodes each. Each switching module is connected to 12 ammeter channels which are switched sequentially to 50 of the 600 electrodes each measurement time. Each ammeter channel is comprised of a current-to-voltage converter, a gain amplifier, filters, an analog to digital converter, and a digital phase sensitive demodulator. Results We found an average noise level of 38 nA, amplitude stability of less than 0.2%, crosstalk of better than -60 dB and 70 dB signal to noise ratio over all channels and operating frequencies. Images were obtained in time difference and frequency difference modes in a saline phantom. Conclusion We describe the design, construction, and calibration of a high density TAM system in detail. Successful high resolution time and frequency difference images showed regions of

  18. Photovoltaic system at Nagaoka College of Technology. Fabrication of photovoltaic system and development of data logging system; Nagaoka kosen ni okeru taiyoko hatsuden. Setsubi no kochiku to data shuroku system no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Arimoto, M.; Shirai, I.; Togawa, K.; Koshoji, H.; Otaki, S. [Nagaoka College of Technology, Niigata (Japan); Murata, M.; Murata, K.; Nomura, M. [New Energy Corp., Tokyo (Japan)

    1997-11-25

    Reported in this paper is a photovoltaic power generation facility built in the yard of Nagaoka College of Technology. The purpose of this study is to find out if such a facility operates effectively in a heavy-snow region. A data logging system is also constructed. In a preliminary experiment, a 50W panel was installed, facing southwest at an inclination of 30degC, on the roof of the schoolhouse. A voltmeter, ammeter, and slide rheostat were used to perform necessary measurement. The panel temperature was approximately 50degC, and insolation was estimated at 70mW/cm{sup 2}. The data logging system is comprised of a personal computer, display, printer, etc. Using this system, voltage and current are measured with the load automatically adjusted, and the maximum power point is sought out and logged. In addition, insolation, ambient temperature, and panel temperature are logged. Data is logged every 10th minute and, when a day`s measurement is over, mean values are obtained for every hour and data is built for a power generation profile, all automatically. There is a plan for a wintertime power generation experiment. 3 refs., 5 figs.

  19. Performance of a 4 Kelvin pulse-tube cooled cryostat with dc SQUID amplifiers for bolometric detector testing

    CERN Document Server

    Barron, Darcy; Keating, Brian; Quillin, Ron; Stebor, Nathan; Wilson, Brandon

    2013-01-01

    The latest generation of cosmic microwave background (CMB) telescopes is searching for the undetected faint signature of gravitational waves from inflation in the polarized signal of the CMB. To achieve the unprecedented levels of sensitivity required, these experiments use arrays of superconducting Transition Edge Sensor (TES) bolometers that are cooled to sub-Kelvin temperatures for photon-noise limited performance. These TES detectors are read out using low- noise SQUID amplifiers. To rapidly test these detectors and similar devices in a laboratory setting, we constructed a cryogenic refrigeration chain consisting of a commercial two-stage pulse-tube cooler, with a base temperature of 3 K, and a closed-cycle 3He/4He/3He sorption cooler, with a base temperature of 220 mK. A commercial dc SQUID system, with sensors cooled to 4 K, was used as a highly-sensitive cryogenic ammeter. Due to the extreme sensitivity of SQUIDs to changing magnetic fields, there are several challenges involving cooling them with puls...

  20. Fabrication and electromagnetic interference shielding effectiveness of polymeric composites filled with silver-coated microorganism cells

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Mingming, E-mail: lan_mingming@163.com [College of Mechanical and Electrical Engineering, Henan Agricultural University, Zhengzhou 450002 (China); Zhang, Deyuan; Cai, Jun; Hu, Yanyan; Yuan, Liming [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2014-07-01

    In this paper, helical silver-coated Spirulina cells were used as conductive fillers for the fabrication of polymeric composites. The morphology and composition of the coated Spirulina cells were analyzed with scanning electron microscope and energy dispersive X-ray spectrometer. The densities of silver-coated Spirulina cells were measured using the standard Archimedes method with distilled water. The electrical resistivity was measured by four-probe technique using ammeter and voltmeter whereas electromagnetic interference shielding effectiveness was measured by four-port method using vector network analyzer and coaxial-airline sample holder. The results showed that the silver-coated Spirulina cells with different coating thickness were lightweight fillers compared to the other typical conductive particles. The polymeric composites could achieve good conductivity at the lower content of silver-coated Spirulina cells owing to their helical shape. The shielding effectiveness of polymeric composites had a strong dependence on their conductivity. At the coating thickness of 0.96 μm and the content of 40 vol%, the shielding effectiveness could reach above 74.3 dB in entire test wave band.

  1. Experimental Investigation of Micro Heat Pipes of Different Cross-Sections Having Same Hydraulic Diameter

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Effects of micro heat pipe (MHP) cross-sections and orientations on its thermal perforrnance are experimentally investigated in this study. Tests are conducted using five different cross-sections (circular, semicircular, elliptical,semi-elliptical and rectangular) of micro heat pipes having same hydraulic diameter of 3 mm placed at three different inclination angles (0°, 45°, 90°), where water is used as the working fluid. Evaporator section of the MHP is heated by an electric heater and the condenser section is cooled by circulation of water in an annular space between condenser section and the water jacket. Temperatures at different locations of the MHP are measured using five calibrated K type thermocouples. Heat supply is varied using a voltage regulator which is measured by a precision ammeter and a voltmeter. It is found that thermal performance tends to deteriorate as the MHP is flattened.Thus among all cross-sections of MHP, circular one exhibits the best thermal performance in terms of heat flux dissipation followed by semi-elliptical, semi-circular, elliptical and rectangular cross-sections. Moreover, its heat transfer capability also decreases with decreasing of its inclination angle. Finally, a correlation is developed which covers all the experimental data within +7%.

  2. Practical Quantum Realization of the Ampere from the Elementary Charge

    Science.gov (United States)

    Brun-Picard, J.; Djordjevic, S.; Leprat, D.; Schopfer, F.; Poirier, W.

    2016-10-01

    One major change of the future revision of the International System of Units is a new definition of the ampere based on the elementary charge e . Replacing the former definition based on Ampère's force law will allow one to fully benefit from quantum physics to realize the ampere. However, a quantum realization of the ampere from e , accurate to within 10-8 in relative value and fulfilling traceability needs, is still missing despite the many efforts made for the development of single-electron tunneling devices. Starting again with Ohm's law, applied here in a quantum circuit combining the quantum Hall resistance and Josephson voltage standards with a superconducting cryogenic amplifier, we report on a practical and universal programmable quantum current generator. We demonstrate that currents generated in the milliampere range are accurately quantized in terms of e fJ (fJ is the Josephson frequency) with measurement uncertainty of 10-8. This new quantum current source, which is able to deliver such accurate currents down to the microampere range, can greatly improve the current measurement traceability, as demonstrated with the calibrations of digital ammeters. In addition, it opens the way to further developments in metrology and in fundamental physics, such as a quantum multimeter or new accurate comparisons to single-electron pumps.

  3. High-performance photoelectrochemical-type self-powered UV photodetector using epitaxial TiO₂/SnO₂ branched heterojunction nanostructure.

    Science.gov (United States)

    Li, Xiaodong; Gao, Caitian; Duan, Huigao; Lu, Bingan; Wang, Youqing; Chen, Lulu; Zhang, Zhenxing; Pan, Xiaojun; Xie, Erqing

    2013-06-10

    TiO₂/SnO₂ branched heterojunction nanostructure with TiO₂ branches on electrospun SnO2 nanofiber (B-SnO₂ NF) networks serves as a model architecture for efficient self-powered UV photodetector based on a photoelectrochemical cell (PECC). The nanostructure simultaneously offers a low degree of charge recombination and a direct pathway for electron transport. Without correcting 64.5% loss of incident photons through light absorption and scattering by the F-doped tin oxide (FTO) glass, the incident power conversion efficiency reaches 14.7% at 330 nm, more than twice as large as the nanocrystalline TiO₂ (TiO₂ NC, 6.4%)-film based PECC. By connecting a PECC to an ammeter, the intensity of UV light is quantified using the output short-circuit photocurrent density (J(sc)) without a power source. Under UV irradiation, the self-powered UV photodetector exhibits a high responsivity of 0.6 A/W, a high on/off ratio of 4550, a rise time of 0.03 s and a decay time of 0.01 s for J(sc) signal. The excellent performance of the B-SnO₂ NF-based PECC type self-powered photodetector will enable significant advancements for next-generation photodetection and photosensing applications.

  4. A Simple Laboratory Experiment to Measure e/k

    Science.gov (United States)

    Inman, Fred

    2005-01-01

    The measurement of fundamental constants is common practice in instructional laboratories. A number of the equipment manufacturers have developed apparatus for such applications, e.g., the determination of e by the Millikan oil drop method or the determination of the speed of light with fiber optics. Other experiments determine not a single constant, but a combination of constants, e.g., e/m by electron beam deflection in a magnetic field or h/e by the photoelectric effect. About 30 years ago Carl E. Miller and I proposed a method of measuring e/k, the ratio of the electron charge to Boltzmann's constant, that was reasonably simple but not necessarily inexpensive because it involved the use of a sensitive electrometer. In recent years, however, inexpensive digital multimeters (DMM), many costing less than 30, have found their way into the physics laboratory. The purpose of this paper is to suggest the use of two DMMs, one operating as a voltmeter and the other as an ammeter, in a simple circuit involving a junction transistor and a variable potential source. Even the potential source can be quite simple, a 1.5-V battery and a 1-kΩ potentiometer, as shown in Fig. 1. If available, a variable dc power supply replacing the battery and potentiometer would be more convenient.

  5. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique

    Science.gov (United States)

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-01-01

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete. PMID:27618054

  6. Effects of Phyllanthus muellerianus Leaf-Extract on Steel-Reinforcement Corrosion in 3.5% NaCl-Immersed Concrete

    Directory of Open Access Journals (Sweden)

    Joshua Olusegun Okeniyi

    2016-10-01

    Full Text Available This paper investigates Phyllanthus muellerianus leaf-extract effects on steel-reinforcement corrosion in concrete immersed in 3.5% NaCl, simulating saline/marine environment. Different concentrations of the leaf-extract were admixed in steel-reinforced concrete samples, which were immersed, with normal control, in the test-environment, while positive control samples were immersed in distilled water. Electrochemical measurements of corrosion-rate (by linear-polarization-resistance instrument, corrosion-current (by zero-resistance-ammeter and corrosion-potential (by high impedance multimeter were obtained for assessing the reinforcing-steel corrosion. Analyzed results showed that the corrosion-rate exhibited excellent correlation (R = 98.82%, Nash-Sutcliffe Efficiency = 97.66%, ANOVA p-value = 0.0006 with function of the admixture concentration and of the corrosion noise-resistance (ratio of corrosion-potential and corrosion-current standard deviations. The 0.3333% Phyllanthus muellerianus (per weight of cement exhibited optimal efficiency, η = 97.58% ± 1.28% (experimental or 95.33% ± 4.25% (predicted, at inhibiting concrete steel-reinforcement corrosion in the test-environment, which compares well with the positive control performance model, η = 97.96% ± 0.03%. The experimental and predicted models followed the Langmuir adsorption isotherm, which indicated physisorption as the Phyllanthus muellerianus leaf-extract adsorption mechanism on the reinforcing-steel. These support suitability of the N-, S-, and O-containing and π-electron rich Phyllanthus muellerianus leaf-extract as an environmentally-friendly inhibitor for effective corrosion-protection of steel-reinforcement in concrete designed for the saline/marine environment.

  7. 基于LabVIEW的磁悬浮轴承的静态刚度测量系统%Measurement System of Static Stiffness for Magnetic Bearings Based on LabVIEW

    Institute of Scientific and Technical Information of China (English)

    马骁; 尹成科; 陈琛

    2012-01-01

    Rotors can be suspended in stators through electromagnetic force in magnetic bearings. The static stiffness is one important technical characteristic of magnetic bearings, so it is a necessary procedure to measure static stiffness for magnetic bearings. A static stiffness measurement system was established up for active magnetic bearings in the open-loop control. This system was based on LabVIEW software development platform, and included X - Y - Z precision motorized stages, six-axis force/torque transducer,laser optical displacement sensor,and high precision ammeter for the most part. An industrial personal computer controlled every measurement cell for automatic measurement, acquisition, and data storage. It has the advantage of high automation.%磁悬浮轴承主要利用电磁力使转子悬浮于定子中,其刚度特性是磁悬浮轴承的重要技术指标,因此磁悬浮轴承的刚度测量是检验磁悬浮轴承性能的必要环节.文中建立了适用于混合控制的磁悬浮轴承在开环控制下的静态刚度测量系统.该系统利用LabVIEW软件开发测量平台,由X-Y -Z电控精密位移台、六自由度力传感器、激光位移传感器及高分辨率电流表等设备组成,并由工控机统一控制各测量单元,实现自动测量、自动采集与数据存储等功能,具有自动化程度高的优点.

  8. Transient current distributions in porous zinc electrodes in KOH electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Liu, M.B.; Yamazaki, Y.; Cook, G.M.; Yao, N.P.

    1981-02-01

    A zero-resistance ammeter circuit with a 10-channel operational amplifier was used to measure the current distribution during a discharge of 10 to 100 mA with simulated zinc porous electrodes in 7.24 M KOH saturated with ZnO. The reaction distribution was found to be highly nonuniform, with 70 to 78% of the charge transfer reaction completed in a depth of 0.01 cm. The high nonuniformity of the initial reaction profile was believed to be due to low conductivity of the electrolyte in the electrode pores. The current distribution changes during passivation of the electrode were experimentally obtained. A mathematical model based upon a macroscope averaging technique was used to predict the time dependence of charge transfer reaction profiles. With mathematical model, current distributions and overpotentials were predicted as a function of time for the segmented zinc electrode discharged at a current of 10 to 100 mA; for these predictions, assumed values of both precipitation rate constants for porous ZnO and diffusion coefficients for hydroxide and zincate ions were used. A gradual decrease in the specific conductivity of the pore electrolyte to 20% of the initial value during discharge yields predictions of current distributions and overpotentials in good agreement with the experimental data. The extent of reduction in the specific conductivity of the pore electrolyte implies a supersaturation of zincate of four times chemical saturation, which was been observed experimentally.At high discharge current (25 to 100 mA), the passivation behavior of the electrode has been simulated. The results of the experiments and mathematical model show that the effective reaction penetration depth is less than 0.02 cm.

  9. Verification and Analysis of Implementing Virtual Electric Devices in Circuit Simulation of Pulsed DC Electrical Devices in the NI MULTISIM 10.1 Environment

    Directory of Open Access Journals (Sweden)

    V. A. Solov'ev

    2015-01-01

    Full Text Available The paper presents the analysis results of the implementation potential and evaluation of the virtual electric devices reliability when conducting circuit simulation of pulsed DC electrical devices in the NI Multisim 10.1environment. It analyses metrological properties of electric measuring devices and sensors of the NI Multisim 10.1environment. To calculate the reliable parameters of periodic non-sinusoidal electrical values based on their physical feasibility the mathematical expressions have been defined.To verify the virtual electric devices a circuit model of the power section of buck DC converter with enabled devices under consideration at its input and output is used as a consumer of pulse current of trapezoidal or triangular form. It is used as an example to show a technique to verify readings of virtual electric measuring devices in the NI Multisim 10.1environment.It is found that when simulating the pulsed DC electric devices to measure average and RMS voltage supply and current consumption values it is advisable to use the probe. Electric device power consumption read from the virtual power meter is equal to its average value, and its displayed power factor is inversely proportional to the input current form factor. To determine the RMS pulsed DC current by ammeter and multi-meter it is necessary to measure current by these devices in DC and AC modes, and then determine the RMS value of measurement results.Virtual electric devices verification has proved the possibility of their application to determine the energy performance of transistor converters for various purposes in the circuit simulation in the NI 10.1 Multisim environment, thus saving time of their designing.

  10. A nano-structured ZnO film as diagnostic X-ray sensor

    Energy Technology Data Exchange (ETDEWEB)

    Valenca, Claudia Patricia Varela; Liborio da Silveira, Matheus Augusto; Macedo, Marcelo Andrade; Pereira dos Santos, Luiz Antonio [CNEN/CRCN-NE Av. Prof. Luiz Freire, 1 Cidade Universitaria RECIFE-PE CEP 50740-540 (Brazil)

    2015-07-01

    Currently some international organizations such as WHO and IAEA have shown concerns about the quality of diagnostic services in clinics and hospitals that use ionizing radiation. In fact, the IAEA recommend that the characteristics of the X-ray beam must be adjusted to obtain the highest quality of the radiographic image with the minimum exposure to the patient. Several types of detectors may be used for monitoring X-ray beams, such as: ionization chamber, photodiode, phototransistor, among others. Recently nano-structured films made of various types of metal oxide materials have been used for various technological applications. Accordingly, the purpose of this paper is to present a sort of device based on a nano-structured zinc oxide (ZnO) to operate as a diagnostic X-ray sensor. By depositing a thin film on the glass substrate some ZnO semiconductor samples were built by sputtering techniques and then mounted in a BNC type connector to perform the electrical characterization. To test the device, we choose a standard X-Ray beam, the RQR9 radiation quality, which is normally used as the tool and condition for calibrating diagnostic X-Ray instruments in the energy range of computed tomography, in accordance with the stated requirements of IEC 61267. A 6430 sub-femto-ammeter, Keithley, was used as electrometer to perform the output readings and simultaneously bias the ZnO sensor. Analysis of the angular dependence and the dose rate were performed to evaluate how the device responds under the RQR9 radiation spectra. Although the results have shown that the ZnO film presents a certain angular dependence, if an angle of incidence of photons is selected, the device displays reproducibility as X-ray sensor and has the feature of radiation hardness unlike other types of semiconductor electronic devices typically used as an X-ray detector. (authors)

  11. Evaluation of the energy dependence of a zinc oxide nanofilm X-ray detector

    Energy Technology Data Exchange (ETDEWEB)

    Valenca, C.P.V., E-mail: claudia.cpvv@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife (Brazil); Silveira, M.A.L.; Macedo, M.A., E-mail: odecamm@gmail.com [Universidade Federal de Sergipe (UFSE), Sao Cristovao, SE (Brazil); Santos, L.A.P, E-mail: lasantos@scients.com.br [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2015-07-01

    International organizations of human health and radiation protection have recommended certain care for using of the X-ray as a diagnosis tool to avoid any type of radiological accident or overdose to the patient. This can be done assessing the parameters of the X-ray equipment and there are various types of detectors available for that: ionizing chamber, electronic semiconductor devices, etc. These detectors must be calibrated so that they can be used for any energy range and such a procedure is correlated with what is called the energy dependence of the detector. In accordance with the stated requirements of IEC 61267, the standard radiation quality beams and irradiation conditions (RQRs) are the tools and techniques for calibrating diagnostic X-Ray instruments and detectors. The purpose of this work is to evaluate the behavior of the energy dependence of a detector fabricated from a zinc oxide (ZnO) nanofilm. A Pantak industrial X-ray equipment was used to generate the RQR radiation quality beams and test three ZnO detector samples. A 6430 sub-femto-ammeter, Keithley, was used to bias the ZnO detector and simultaneously perform the output readings. The results showed that the ZnO device has some increase in its sensitivity to the ionizing radiation as the X-ray effective energy decreases unlike other types of semiconductor electronic devices typically used as an X-ray detector. We can conclude that the ZnO device can be used as a diagnostic X-ray detector with an appropriate calibration. (author)

  12. The Integrated Demonstration Instrument of Peltier Effect and Seebeck Effect%珀尔帖效应与塞贝克效应综合演示仪

    Institute of Scientific and Technical Information of China (English)

    陈文娟; 薛德宽; 黄兴洲; 位浩杰; 刘冰

    2015-01-01

    A Peltier and Seebeck effects integrated demonstrator Design, which overcomes theflaws of traditional demonstrator only demonstrating an effect. DS18B20 temperature sensor and WH7016M temperature controller are used to control the cooling temperature,displaying cooling temperature on the computer by Lab-VIEW software. The voltmeter and ammeter show the voltage and current when TEC cooling and power genera-tion. It overcomes the weakness of other demonstrators not quantitative demonstration and only showing one effect. It also realizes the function of temperature change displayed by computer graphics. This instrument is a simple,stable performance,which achieves good results in the classroom demonstration.%设计制作了珀尔帖效应与塞贝克效应综合演示仪。采用 DS18B20温度传感器和WH7016M温度控制器控制制冷温度,利用LabVIEW软件在电脑上显示制冷温度变化曲线。通过电压表电流表显示温差半导体制冷和发电时的电压电流。该演示仪既克服了以往此类演示仪不能定量演示且只能演示一种效应的缺点,又实现了温度变化用计算机图形演示的功能。该仪器操作简单、性能稳定、效果明显,在课堂演示中取得了良好的效果。

  13. Heat Transfer of Single and Binary Systems inPool Boiling

    Directory of Open Access Journals (Sweden)

    Abbas J. Sultan

    2010-01-01

    Full Text Available The present research focuses on the study of the effect of mass transfer resistance on the rate of heat transfer in pool boiling. The nucleate pool boiling heat transfer coefficients for binary mixtures (ethanol-n-butanol, acetone-n-butanol, acetone-ethanol, hexane-benzene, hexane-heptane, and methanol-water were measured at different concentrations of the more volatile components. The systems chosen covered a wide range of mixture behaviors.The experimental set up for the present investigation includes electric heating element submerged in the test liquid mounted vertically. Thermocouple and a digital indictor measured the temperature of the heater surface. The actual heat transfer rate being obtained by multiplying the voltmeter and ammeter readings. A water cooled coil condenses the vapor produced by the heat input and the liquid formed returns to the cylinder for re-evaporation.The boiling results show that the nucleate pool boiling heat transfer coefficients of binary mixtures were always lower than the pure components nucleate pool boiling heat transfer coefficients. This confirmed that the mass transfer resistance to the movement of the more volatile component was responsible for decrease in heat transfer and that the maximum deterioration that was observed at a point was the absolute concentration differences between vapor and liquid phases at their maximum. All the data points were tested with the most widely known correlations namely those of Calus-Leonidopoulos, Fujita and Thome. It was found that Thome's correlation is the more representative form, for it gave the least mean and standard deviations

  14. A state of the art on electrochemical noise technique. Assessment of corrosion characteristics and development of remedial technology in nuclear materials

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Jin; Kim, Joung Soo; Kim, Hong Pyo; Lim, Yun Soo; Yi, Yong Sun; Chung, Man Kyo

    2003-02-01

    The studies for the application of electrochemical noise technique were reviewed in terms of principle, analysing method and application examples of this technique. Because 4% of the economic damage of industry is caused by metallic corrosion, it is important to find and protect corrosive materials and location. By corrosion monitoring of industrial facilities such as nuclear power plant using Electrochemical Noise Measurement(ENM), corrosion attack can be detected and furthermore it can be indicated whether the attacked materials is replaced by new one or not. According to development of control and electronic technology, it was easy to apply ENM to the industry and the interest in ENM also increased. As corrosion is produced on a metal under corrosive environment, local anode(oxidation) and cathode(reduction) are formed. Hence, there is potential difference and current flow between the anode and cathode. ENM is monitoring the potential difference and the current flow with time by high impedance load voltmeter and Zero Resistance Ammeter(ZRA), respectively. The potential difference and current flow generated spontaneously without any application of current and potential between electrodes are monitored by electrochemical noise technique, Thereby ENM can be regarded as the most ideal corrosion monitoring method for the industrial facility and nuclear power plant having corrosion damage and difficulty in access of human body. Moreover, it is possible to obtain the spontaneous and reliable results from the metals damaged by ununiform and localized corrosion such as pitting and SCC using ENM while it is difficult to obtain the reliable result using traditional linear polarization and ac-impedance measurement. In many countries, there are extensive works concerned with application of electrochemical noise technique to corrosion monitoring of nuclear power plant and other industrial facilities, whereas there is little work on this field in Korea. Systematic study for

  15. 医用诊断X光机管电流测试系统的设计与实现%Design and Implementation of Medical Diagnostic X -ray Machine's Tube Current Testing System

    Institute of Scientific and Technical Information of China (English)

    黄平; 方方; 刘志宏

    2011-01-01

    As an important parameter, Medical X-ray tube current control the X - ray intensity, which has been included in the JJG 744 - 2004 " Medical Diagnostic X-ray radiation sources" in the state verification procedures. With the continuous development of the digital diagnosis and treatment, traditional ammeter is not a-ble to measure the X - ray tube current and exposure time accuratly, in order to ensure safety and reliable operation of Medical X - ray machine , improve the corresponding level of digital detection, so designing a verifaction of non - intrusive system of tube current, which include FPGA combination of high speed ADC digital sampling technology, current transformers and Bluetooth technology. The system has obvious advantages on the diversification of measured parameters and the accuracy of data analysising, has more in line with the characteristics of tube current. At the same time with high accuracy and good repeatability, the system meet national requirements of testing procedures.%X光机管电流作为控制X射线强度的重要参数,已被包含在JJG 744 - 2004《医用诊断X射线辐射源》国家计量检定规程中.随着数字诊断治疗水平的不断发展,传统电流表已不能准确测量X光机管电流与曝光时间,为了保障医用X光机安全可靠运行,提高与之相应的数字化检测水平,设计验证了一套包含高速ADC与FPGA结合的数字化采样技术、电流互感器与蓝牙技术的非介入式管电流测试系统,该系统在测量参数多样化、数据分析准确性方面优势明显,较符合X光机管电流特征,具有测量精度高、重复性好等优点,满足国家检定规程要求.

  16. Design for high-precision and quick-response digital multifunction meter based on STM32 and AD7606%基于 STM32与 AD7606的高精度和快速响应数字多功能表的设计

    Institute of Scientific and Technical Information of China (English)

    徐国明; 徐燕明; 曹达; 袁建香; 李生辉

    2015-01-01

    针对国内传统的变送器或电表普遍存在响应时间较长或精度不高的实际状况,介绍一种基于STM32与AD7606为核心的数字多功能表的设计方案。该方案采用模块化设计,包括信号采集、数据处理、显示、按键、通讯和变送输出等。信号采集部分采用16位高精度同步采样ADC,同时,电流线路采用有源补偿方式,确保了整个测量段的数据精度;变送输出采用16位高性能DAC转换器,能够以最高30MHz的时钟速率工作。系统以每周期256点为采样点数,同时在算法上采用了逐点处理的方法,使得数据精度高,实时性好。基于ARM内核32位MCU,系统能够独立完成所需主要数据的采集、计算、显示和存储等工作。%In view of the actual situation that domestic traditional transmitter or ammeter has the problems of long re-sponse time or low precision, in this paper, design scheme for a digital multifunction meter based on STM32 and AD7606 is introduced.The scheme adopts modular design, including signal collection, data processing, display, but-ton, communication and transmitting output, etc.The signal collection part adopts 16 bits high-precision synchronous sampling ADC, at the same time, current circuit adopts the active compensation mode, which ensures the data preci-sion of the whole measurement section;transmitting output adopts 16 bits high-performance DAC converter, which can work at the highest clock rate of 30MHz.The system takes 256 bits of every cycle as sampling number, meanwhile, it adopts point-by-point processing method in algorithm, thus, high data precision and good real time are obtained. Based on ARM core 32 bits of MCU, the system can complete the collection, calculation, display and storage of key data required independently.

  17. Part I. Corrosion studies of continuous alumina fiber reinforced aluminum-matrix composites. Part II. Galvanic corrosion between continuous alumina fiber reinforced aluminum-matrix composites and 4340 steel

    Science.gov (United States)

    Zhu, Jun

    uncoupled coupons were immersed in various electrolytes, exposed to a humidity chamber, and exposed at outdoor test sites. Results showed that the corrosion rates of the CF-AMCs increased, while those of the 4340 steel decreased after being coupled together, in most cases. Crevice corrosion was also observed in these exposure experiments. Zero resistance ammeter (ZRA) experiments were conducted to record the galvanic-corrosion rates and potentials of the couples. The CF-AMCs were found to serve as anodes, while the steel was cathodic, in most test conditions. Galvanic performance predicted by polarization experiments was in close agreement with the ZRA results. Key words. Aluminum, metal-matrix composites, alumina fiber, pitting corrosion, galvanic corrosion.

  18. 配位体交换-流动注射分析法测定水中有效氰化物%Determination of available cyanide in water by ligand exchange-flow injection analysis

    Institute of Scientific and Technical Information of China (English)

    乔小宇; 李华昌; 于力; 张萍

    2012-01-01

    A method for the determination of the available cyanide,namely, the total of cyanide including ions (CN-),HCN (aq),as well as zinc,copper,cadmium,mercury,nickel and silver cyanide complexes in water by ligand exchange reagents and CNSolution FS 3100 cyanide analyzer, has been studied. Gaseous HCN which was generated in the reaction module entered into alkaline absorption solution by gas diffusion diaphragm (GD) and was converted to cyanide ions (CN- ) ,and then was detected by ammeter in the flow testing pool. The interference of methanal, phenol, sodium hypochlorite, and sulfide to the determination of CN~ was inspected and removed. The experiment results indicated that, in the range of cyanide concentration between 2. 0-1 000 μg/L,r>0. 999 6;the detection limit of method was 0. 6 μg /L;the relative standard deviation (RSD) (n = 5) was smaller than 2. 5%,the recoveries of real samples were 92%-102%. It can be applied to detect the available cyanide in large a-mount of surface water,groundwater,drinking water and wastewater of petroleum chemical industry, metallurgy, electroplating, papermaking.%研究了采用配位体交换试剂和CNSolution FS 3100氰化物分析系统检测水中有效氰化物(即CN、HCN(aq)以及锌、铜、镉、汞、镍和银的氰络合物的总和)的分析方法.在反应模块中生成的气态HCN通过气体扩散膜片(GD)进入碱性吸收液中并转换为CN,然后进入流动检测池由安培计检测.考察了甲醛类化合物、苯酚化合物、次氯酸钠及硫化物等对CN测定的干扰及消除方法.实验结果表明,CN浓度在2.0~1 000 μg/L范围内,线性相关系数r>0.999 6;检出限为0.6 μg/L;RSD(n=5)<2.5%;实际样品加标回收率为92%~102%.该方法可应用于大批量地表水、地下水、饮用水及石油化工、冶金、电镀、造纸等行业废水中有效氰化物的测定.

  19. Basic functions of telecommunication channel elements for successful information transmission

    Directory of Open Access Journals (Sweden)

    Milorad S. Markagić

    2011-04-01

    Full Text Available The challenge in the field of multimedia telecommunications is an attempt to integrate texts, sound, images and videos coherently and consistently and to ensure simplicity and interactivity of operation. In order to make the proposed multimedia applications acceptable to end-users, the quality of transmission through the network and message presentation should have special attention. The main aims of this paper are the introduction to the communication channel with its basic elements, a detailed description of the information source and the presentation of possible approaches to the analysis of the telecommunication channel. Introduction In the age of mass application of various communication means, end-users of telecommunication channel elements rarely pay attention to the processes taking place in everyday communication and the elements presented in the channel. In order to discuss all the factors that influence the establishment and maintenance of the links, this paper will explain the basic elements of telecommunication channels. Source Every object that generates messages to be transferred to a recipient is called the source of the message. Directors, writers, speakers, books, newspapers, various instruments (thermometer, barometer, ammeter, etc., computers, a man himself - these are all sources of various messages. In relation to facilities that generate messages, there are different sources of messages. All the messages that they generate belong to discrete or continuous modes of messages. Discrete messages can be presented with element sets, where elements can be considered through different values of observed messages. Each text message of arbitrary length, for example, is made of a finite number of elements - symbols (letters, numbers, punctuation marks, from the set of symbols called the alphabet message source. Continuous messages can be presented with an infinite number of sets of elements where elements can have different values of

  20. Investigation of the chemical and electrochemical phenomena in the chemical mechanical planarization of copper

    Science.gov (United States)

    Wang, Ling

    uncoupled copper, tantalum and titanium electrodes were obtained in commercial slurry and solutions containing hydrogen peroxide and glycine, for assessing the polarity between copper and tantalum when forming a galvanic couple, as function of peroxide concentrations, solution pHs, and the impact of diluting the slurry on the galvanic interaction. Galvanic currents and mixed corrosion potentials were measured in tantalum-copper couples formed by short-circuiting the two specimen electrodes in a three-electrode cell through a potentiostat-based zero resistance ammeter, to verify the correlation between the polarity and the galvanic interactions and to assess the effects of solution composition and the tantalum-to-copper surface area ratio. The results showed that the material removal due to galvanic interaction under non-polishing conditions is negligibly small, but could be a potential issue during CMP, and either copper or tantalum barrier material could experience accelerated corrosion, depending on the solution composition. The galvanic interaction between copper and tantalum is sensitive to the solution composition. Acidic acetate/acetic acid buffer may transiently accelerate the galvanic corrosion of copper, while basic carbonate/bicarbonate buffer may transiently accelerate the galvanic corrosion of tantalum. Glycine promotes galvanic corrosion of copper. Hydrogen peroxide is the most effective component to exacerbate galvanic corrosion between copper and tantalum, with tantalum experiencing accelerated corrosion. Changing the surface area of tantalum, which has the more active corrosion, has a less significant effect on the galvanic corrosion than changing the surface areas of the copper, which has a more noble potential.

  1. The Chemical and Educational Appeal of the Orange Juice Clock

    Science.gov (United States)

    Kelter, Paul B.; Carr, James D.; Johnson, Tanya; Mauricio Castro-Acuña, Carlos

    1996-12-01

    difference between the open circuit voltage (1.772 V) and the voltage with a known resistance (1.037 V). The difference, 1.772 - 1.037 = 0.735 V, equals the product of the circuit current and the resistance of the orange juice (ROJ), or ROJ = 0.735 V/0.001037 A = 708 Ohm 4. Finally, measure the current that the clock itself requires by hooking up in series an ammeter to the battery and the clock. The reading is not easy to take with an ammeter, which does not sample very often, and integrates across time. The computer interface works better for this. In our clock, a current of 0.49 mA was used. 5. The payoff comes at this point. The predicted voltage drop (I x Rint) can be calculated, voltage drop = I x Rint = 0.00049 A x 708 Ohm = 0.35 V Our observed voltage drops for this system were typically around 0.30 V. As a confirmation of the relationship of internal resistance to voltage drop, we placed the strips 1 mm apart in an orange by digging 2 holes in the orange and placing into the holes the coiled parts of the strips. We expected the voltage drop to be much higher than with the juice, due to the much higher internal resistance of the orange. Even when the strips were nearly touching, the drop was about 1 V. The Water Clock We discussed above the difference in the redox system when water is used rather than orange juice. Distilled water, which has a high internal resistance, will not permit the clock to run. However, hard tap water or distilled water with, for example, 1 g of table salt in 300 mL of water will work fine. As expected, because of the lower hydrogen ion concentration, the initial cell voltage is lower, typically around 1.45 V. The clock also ticks more slowly and more softly in water than in orange juice. In water, a black precipitate forms on the magnesium electrode and becomes more extensive with time. When the strip is removed from distilled water, and allowed to dry the precipitate turns white. Further student exploration on the precipitate might include