conductivity sensor Articles

  • Calibration of Thermal Conductivity Sensors for Measuring Soil Suction

    The accuracy of suction measurements using thermal conductivity sensors is dependent upon their calibration. Therefore, a calibration study was undertaken by using a modified, commercially available, pressure plate extractor. The experimental setup along with the calibration procedure are described. Typical calibration results are presented. In general, results showed reasonable agreement between ...


    By ASTM International

  • Numerical Modeling of a Thermal Conductivity Matric Suction Sensor

    Thermal conductivity matric suction sensors appear to be a promising device for the measurement of suction in soil. The technique indirectly measures matric suction by measuring the thermal conductivity of a ceramic block. This paper uses both a spherical and a cylindrical porous medium to simulate the heat flow in a thermal conductivity matric suction sensor. It is found that, although the ...


    By ASTM International

  • Tech Tip: Deploying Sea-Bird CTD in Ice

    Large numbers of Sea-Bird conductivity instruments have been used in Arctic and Antarctic programs. Special accommodation to keep temperature, conductivity, oxygen, and optical sensors at or above 0° C is advised. Often, the CTD is brought inside protective doors between casts to achieve this. Conductivity Cell When freezing is possible, we ...

  • Arctic Polar Research - A Global Responsibility

    Due to climate change and geopolitical trends, the Polar Regions (particularly the Arctic) are increasingly becoming the focus of scientific, political, and economic interests. Much of the global climate is driven by forces that originate in the Arctic. The Arctic sea ice is receding faster than climate models have predicted, and the movement of freshwater into and around the Arctic plays an ...

  • Conductivity Theory and Measurement

    Electrical conductivity is a measure of the ability of a solution to cany* a current. Current flow in liquids differs from mat in metal conductors in that electrons cannot flow freely, but must be carried by ions. Ions are formed when a solid such as salt is dissolved in a liquid to form electrical components having opposite electrical charges. For example, sodium chloride separates to form Na" ...


    By IC Controls Ltd.

  • Quantum dots and nanostructured conducting polymers for biosensing applications

    Numerous methodologies are currently being employed for the preparation of nanomaterials in customised morphologies. In this paper, we outline recent progress in our laboratory to develop nanostructured inorganic semiconductors – quantum dots (QDs), and nanostructured organic semiconductors based on polyaniline (PANI), for biosensing applications. Blue luminescent CdTe QDs were prepared directly ...


    By Inderscience Publishers

  • Transparent conductive oxide materials: financial stakes and technological challenges

    Although transparent conductive oxides (TCOs) have been known and used for quite some time, research on these materials is still very active to improve their characteristics. This paper is aimed at giving an overview of the contribution of the TCO materials to the economy in various fields of applications (flat panel displays, photovoltaics, light-emitting diodes, smart windows, gas sensors, ...


    By Inderscience Publishers

  • The Thermal Probe—Measurement of the Thermal Conductivity and Drying Rate of Soil in the Field

    The thermal probe is a metal rod with an internal heating element and temperature sensor. In the field it is pushed into a predrilled hole in otherwise undisturbed soil, and the thermal properties of the soil are estimated from the temperatures recorded at intervals after a constant power is supplied to the heating element. The following are discussed in this paper: the theory behind the methods ...


    By ASTM International

  • Conductivity Measurement in high purity water samples below 10 microsiems/cm

    High Purity Water Resistivity/ Conductivity Measurement Ultra-Pure Water without any chemical impurities will still have a conductivity because of the presence of H* and OH" ions due to the self-ionization of water. Ultra-pure water has a conductivity of 0.055 HSiemens'cm or a resistivity of 18.18 mQ-cm at 25 °C. In order to know the conductivity or resistivity of ultra-pure water it is ...


    By IC Controls Ltd.

  • Sensors & Automation to Simplify Bioprocess Operations

    Utilising sensors & automation to simplify bioprocess operations means that more work can be done in less time. By automating the routine tasks carried out in the lab, valuable time can be devoted to more important tasks. Here are two practical examples of automating routine tasks in upstream and downstream bioprocessing with relatively simple instrumentation. Automated ...


    By Broadley-James Ltd

  • Electrical conductivity as a state indicator for the start-up period of anaerobic fixed-bed reactors

    The aim of this work was to analyse the applicability of electrical conductivity sensors for on-line monitoring the start-up period of an anaerobic fixed-bed reactor. The evolution of bicarbonate concentration and methane production rate was analysed. Strong linear relationships between electrical conductivity and both bicarbonate concentration and methane production rate were observed. ...


    By IWA Publishing

  • Instrumentation and Operational Considerations for On-Line pH Measurement in Samples Below 10µS/cm Conductivity

    Ordinarily pH measurements are made in water with 1,000 to 10,000 µS/cm conductivity. The conductivity comes from dissolved solids which are typically salts but also acid or base. These dissolved substances are in the solution in ion form which makes such solutions conducting. With conductivities of 1,000 µS/ cm or more, an ample supply of mobile ions provides pH electrodes with a ...


    By IC Controls Ltd.

  • Designing PEDOT–based sensors for antioxidant analysis

    Antioxidants play important roles in food quality and the protection and promotion of human health. The most commonly used antioxidant determination techniques are the Folin–Ciocalteu assay and HPLC analyses. However, these methods have various disadvantages such as long time requirements, low sensitivity, interfering agents etc. Cyclic voltammetry at inert electrodes is another method for ...


    By Inderscience Publishers

  • Case Study: Liz Bagshaw on the IRC sensors

    Our infrared IR’C sensors have been making waves in the world of glacial meltwater monitoring. Glacial environments are key indicators of global warming and climate change. They’re also home to a diverse range of microorganisms. Both of these need to be quantified and monitored, but doing this isn’t easy because of the cold, remote environments in which they are found. To combat ...


    By Partech (Electronics) Ltd.

  • Upgrading from Pellistor Gas Sensors to Infrared Technology

    In this article Andy Avenell, Crowcon’s Fixed Systems Product Manager, considers the shift towards infrared (IR) gas sensor technology in the oil and gas industry. Abstract Flammable gases and vapours can present considerable dangers in many industrial applications, none more so than the processes involved in extracting, transporting and processing oil and gas. Fast and reliable ...

  • Accuracy in temperature sensor response time estimation for new nuclear reactor designs

    One method for measuring the response time of temperature sensors, the plunge test, verifies that the sensor has a suitable response time in the laboratory before installation. However, plunge test results cannot be extrapolated to the response time in an operating plant because response time is affected by multiple factors such as the ratio of internal heat-transfer resistance to the surface ...


    By Inderscience Publishers

  • A molecular imprinted polymer based sensor for measuring phosphate in wastewater samples

    Phosphate detection in water samples is still completed using colorimetric standard methods, which have a number of disadvantages, to such as being time consuming, requiring filtration, a number of different reagents, frequent calibration and proper disposal of waste chemicals generated. Hence, a simple cost effective analytical method and instrumentation is highly desirable to aid the ...


    By IWA Publishing

  • Calibration and characterization of an improved low-cost water content sensor

    Inexpensive, accurate, and reliable soil moisture measurements are necessary in countless applications from research to hydroponics. Many have dreamed of these types of sensors being so inexpensive that they could be spread over a wide area to monitor water status at numerous locationsin a watershed, greenhouse, or golf course to name a few. However, measurements of this sort are only as valuable ...


    By Decagon Devices, Inc.

  • Application of nanocrystalline metal oxide gas sensors for air quality monitoring

    Increasing concern regarding health effects caused by air pollution, together with the limited spatial resolution achievable with conventional monitoring stations, have driven efforts to develop inexpensive metal oxide gas sensors for air quality measurements. The sensing mechanism is dependent on physicochemical reactions between adsorbed gas molecules and oxygen species on the oxide surface, ...


    By Inderscience Publishers

  • Impact parameters investigation of DNA immobilisation process on DNA sensor response

    This paper studies impact parameters of DNA sequence immobilisation on DNA sensor response. The parameters were examined including immobilisation time, carbon nanotubes concentration, DNA probe concentration and pH value. The DNA probe sequences were immobilised on surface of microelectrodes by using multi–walled carbon nanotubes (MWCNTs) as mediator. The hybridisation between DNA probe and DNA ...


    By Inderscience Publishers

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