optical measurement Articles

  • Simultaneous determination of PM fractions, particle number and particle size distribution in high time resolution applying one and the same optical measurement technique

    Abstract The Fidas fine dust monitoring systems comprise an optical aerosol spectrometer, which is characterized by very good instrument characteristics, and utilize a sophisticated approach to convert the measured information on particle number and particle size into mass concentrations. As monitoring of PM requires reliable and quality-controlled performance of the measuring systems, ...


    By Palas GmbH

  • Optical measurement of oxygen concentration in water

    The optimisation of oxygen transfer is a key element of control and regulation strategies in municipal and industrial sewage treatment plants. In 2003, HACH LANGE became the first instrument manufacturer to launch the LDO (Luminescent Dissolved Oxygen) method for determining dissolved oxygen in water. The LDO technology is based on pulsed blue light, which brings benefits such as high precision, ...


  • 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 ...

  • Optical bioassay for measuring sublethal toxicity of insecticides in Daphnia pulex

    Many emerging contaminants tend to be biologically active at very low concentrations, occur in water as part of complex mixtures, and impact biota in ways that are not detected using traditional toxicity tests (e.g., median lethal concentration). To evaluate emerging contaminants, the authors developed a method for detecting sublethal behavioral effects by quantifying the swimming behavior of ...


    By John Wiley & Sons, Ltd.

  • Particle Optics in the Rayleigh Regime

    Light scattering and absorption by particles suspended in the atmosphere modifies the transfer of solar energy in the atmosphere, thereby influencing global and regional climate change and atmospheric visibility. Of particular interest are the optical properties of particles in the Rayleigh regime, where particles are small compared with the wavelength of the scattered or absorbed light, because ...

  • Optical encoders and LiDAR scanning

    Overview Modern technology is taken for granted; a driver only needs to type a destination into a SATNAV system and step-by-step instructions, journey distance and duration, driving conditions and hazards, as well as alternative routes, instantly appear. In order to work, highly accurate and up-to-date maps are required of an entire country's road ...


    By Renishaw plc

  • Measurement of hydrocarbons in produced water using fiber optic sensor technology

    Due to the non-availability of Freon, there is need for an alternative method to measure the concentration of hydrocarbons in the effluent from oil water separators in use in the oil industry today. Current methods use solvent extraction and IR analysis of water samples. In this paper we present an alternative method, which does not use any solvents and can provide in-situ analysis of the ...


    By PetroSense, Inc

  • Comparing Optical Turbidity With LISST-ABS

    For measuring suspended sediments, the use of optical backscatter sensors or other turdibity sensors is widespread. At the same time, it is understood that these sensors respond to total particle area, not volume or mass. In other words, optical turbidity sensors have this property: their sensitivity decreases with increasing grain size. The decrease follows 1/diameter. This has been published ...


    By Sequoia Scientific, Inc.

  • Long optical paths of large aperture

    THE measurement of the vapor phase spectra of compounds having high boiling points presents an experimental problem that may be solved either by heating the absorption cells or by making them very long. In the infra-red region radiation from the hot gases in heated cells decreases the accuracy of absorption measurements. If only a small amount of sample is available, the only possibility is to ...


    By CIC Photonics, Inc.

  • Optical Remote Sensing in the United States

    Recent studies that involve the use of optical remote sensing (ORS) techniques to measure gaseous and particulate pollutants have rekindled interest among environmental researchers and regulators in this decades-old technology. This article describes some of the key research and development projects that are helping restore ORS-based methods to the list of currently available emissions ...


    By Arcadis

  • Optical Assessment of Dissolved Organic Carbon

    Natural organic matter is present in all sources of drinking water. When chlorine is used for drinking-water treatment, a portion of the natural organic matter reacts to form halogenated compounds, referred to as disinfection by-products (DBPs), some of which are regulated by the USEPA due to their health effects. The implementation of stricter drinking-water quality regulations for DBPs has ...

  • Measurement of Hydrocarbons in Produced Water Using Fiber Optic Sensor Technology (An Alternative to Freon Extraction and IR Analysis Methods)

    Due to the non-availability of Freon, there is need for an alternative method to measure the concentration of hydrocarbons in the effluent from oil water separators in use in the oil industry today. Current methods use solvent extraction and IR analysis of water samples. In this paper we present an alternative method, which does not use any solvents and can provide in-situ analysis of the ...


    By PetroSense, Inc

  • Relationship between Particulate Matter measured by Optical Particle Counter and Mortality in Seoul, Korea, during 2001

    This study was performed to examine the relationship between particulate matter exposure and mortality in Seoul, Korea, during the year 2001. Particulate matter data were collected using an optical particle counter (OPC) and national monitoring stations in Seoul. The size-resolved aerosol number concentrations of particles 0.325 μm in diameter and mass concentrations of PM10 ...

  • A machine learning approach for estimation of shallow water depths from optical satellite images and sonar measurements

    There has been a rapid growth in the field of remote sensing and its various applications in the area of water management. Nowadays, there are several remote sensing techniques that can be used as a source to derive bathymetry data along coastal areas. The key techniques are: sonar (sound navigating and ranging), LiDAR (light detection and ranging) and high-resolution satellite images. The ...


    By IWA Publishing

  • Monitoring ecosystem optical properties with the UniSpec-SC

    Understanding patterns of ecosystem properties is important if we are to effectively monitor ecosystem change due to a variety of reasons (e.g. global changes, human management). Remote sensing provides a great tool for monitoring the earth's surface at different temporal and spatial scales. Patterns of vegetation and biodiversity dynamics are important ecosystem properties, with strong links to ...


    By PP Systems

  • Optical properties of LiF:Mg,Cu,P nanorods

    Nanorods of LiF:Mg,Cu,P synthesized by the chemical co-precipitation technique have been investigated for their optical properties. Photoluminescence (PL) emission and excitation spectra and UV-visible absorption spectrum have been investigated in this paper. PL emission spectrum shows a wide emission band located at the range 350 nm-450 nm along with emerging of a sharp intense band at 376 nm. ...


    By Inderscience Publishers

  • Advances in Optical Techniques for Moisture and Hydrocarbon Detection

    Abstract Every year, the world uses in the region of 100 trillion scf (standard cubic feet) of natural gas (1). All of this gas requires treatment before it enters the pipeline, making natural gas processing a key global industry. Minimization of costs is achieved through optimization of these processes, requiring accurate online measurement of gas composition at multiple points in the ...


  • Plasmon-enhanced optical transmission of nanostructured metallic multilayers

    Surface plasmons (SPs) – charge oscillations on metallo-dielectric interfaces – offer the possibility of controlling light at a scale much smaller than its wavelength, even down to the nanometre scale for visible wavelengths. Experiments have been performed to study the influence of SPs on the optical transmission of metallic multilayers in which one of the layers has been patterned at the ...


    By Inderscience Publishers

  • The effects of hydrogen on the electrical and optical properties of ZnO

    Hydrogen atoms introduced into oxides are considered to modify the electronic structure of the compounds. The effect of hydrogen on the electrical and optical properties of zinc oxide (ZnO) films was examined. The electronic state of hydrogen-doped ZnO films was studied by Ultraviolet Photoelectron Spectroscopy (UPS) and cathode luminescence measurements. Hydrogen introduced in ZnO forms impurity ...


    By Inderscience Publishers

  • Characterisation and nonlinear optical properties of CdS nano-particles

    CdS nano-particles have been synthesised using chemical precipitation. The formation and microstructure of CdS nano-particles were monitored by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectrum and z-scan technique. Using the UV-Visible, the band gap of this nano-particle is obtained about 3.54 eV and the spectrum of this material shows a 310 nm peak. X-ray diffraction ...


    By Inderscience Publishers

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