sampling tube Articles

  • A Simulation of Tube Sampling Effects on the Stiffness of Clays

    The effect of tube sampling disturbance on the prefailure behavior of reconstituted kaolin was investigated in the triaxial cell. Previously published forms of stress paths followed by normally consolidated and overconsolidated clays during simulated sampling have been substantiated. After the initial stresses were restored, the behavior of the undisturbed clay at small strains (up to 0.1%) was ...


    By ASTM International

  • Analysis of Stack Emissions Using VOST Air Sampling Tubes and Capillary GC

    United States EPA SW-846, Method 0030, Volatile Organic Sampling Train (VOST), describes the sampling of emissions for volatile compounds from hazardous waste incinerator stacks. Supelco's VOST air sampling tubes are designed to fulfill the method requirements and provide low background levels.               ...


    By Sigma-Aldrich Co., LLC

  • The Preparation of Hollow Cylinder Specimens from Undisturbed Tube Samples of Soft Clay

    The use of torsional-hollow cylinder testing apparatus for research into soil stress-strain behavior has grown over the past decade. Most studies have focused on sands or on cohesive materials reconstituted in the laboratory. Studies involving undisturbed soft clay have been neglected, in part due to the difficulties involved in specimen preparation.The present paper describes a procedure for the ...


    By ASTM International

  • Fermentation tube test statistics for direct water sampling and comments on the Thomas formula

    This article describes a new interpretation of the Fermentation Tube Test (FTT) performed on water samples drawn from natural waters polluted by faecal bacteria. A novel general procedure to calculate the Most Probable Number of bacteria (MPN) in natural waters has been derived for the FTT for both direct and independent repetitive multiple water sampling. The generalization based on solving the ...


    By IWA Publishing

  • Sampling of Carbonyls Using a Dual-Layer LpDNPH Glass Sampling Tube and HPLC Analysis

    The dual-layer LpDNPH sorbent tube is an air sampling device designed for sampling carbonyls (e.g. formaldehyde) in ambient, indoor, and industrial atmospheres. Carbonyls are trapped on our high-purity silica gel adsorbent coated with 2,4-dinitrophenylhydrazine (2,4-DNPH) where they are converted to stable hydrazone derivatives. The derivatives are eluted from the tube in acetonitrile and ...


    By Sigma-Aldrich Co., LLC

  • Sampling trace-level organic solutes with polymeric tubing. Part 2. Dynamic studies

    Parker and Ranney present the results of laboratory tests focused on investigation the potential positive or negative biases associated with using polymetric tubing to collect groundwater samples. This paper, the second in a series, focuses on the effects under dynamic (i.e., pumping) conditions. They show that negative biases are a function of the plymer material, the hydrophobicity of the ...


    By Solinst Canada Ltd.

  • The Effects of Centerline Tube Sampling Strains on the Undrained Behavior of Two Stiff Overconsolidated Clays

    Some of the effects of tube sampling of stiff clays are examined. A strain path that simulates strains at the centerline of a tube sample as it is captured by a penetrating sampling tube was applied in the triaxial apparatus. Undrained triaxial strain path tests were performed on two stiff overconsolidated clays that had not previously been subjected to tube sampling. The response of the clays ...


    By ASTM International

  • Joint estimation of hydraulic conductivities of two sand samples in a W-tube system with a bi-exponential response

    The motivation for this paper is the practical problem of interpreting bi-exponential rate-of-rise curves that are observed during many field piezometric tests. In the authors' previous study, a laboratory W-tube system of water flow through two samples of sand was introduced with an adequate mathematical model. The desired bi-exponential character of water flow was obtained by placing two ...


    By IWA Publishing

  • Carbonyl Sampling and Analysis by HPLC

    Sampling of Carbonyls Using a Dual-Layer LpDNPH Glass Sampling Tube and HPLC Analysis with an Ascentis Express C18 Column The dual-layer LpDNPH ORBO-555 tube is an effective sampler for measuring airborne carbonyl concentration. The low background levels in the sampler allow for accurate measurements of low concentration samples or samples collected in ...


    By Sigma-Aldrich Co., LLC

  • Enhanced acoustic material testing in a tube

    Demands from the Industry   A growing number of customers demand quieter vehicle cabins, and cabin acoustic comfort has become a major concern for the automotive industry. Optimization of the acoustic insulation performance has, therefore, been given a more prevalent role in the design process. In the aircraft industry, acoustic comfort for customers and the use of new, lighter ...

  • Sampling moisture in the soil profile

    Patterns of water replenishment and use give rise to large spatial variations in soil moisture over the depth of the soil profile. Accurate measurements of profile water content are therefore the basis of any water budget study. When monitored accurately, profile measurements show the rates of water use, amounts of deep percolation, and amounts of water stored for plant use.Experimental ...


    By Decagon Devices, Inc.

  • Knotted in-tube and mini-column solid phase extraction of polycyclic aromatic compounds and nitroaromatics from aqueous samples for their determination by gas chromatography–mass spectrometry

    The selectivity of in-tube extraction by PTFE tubing vis-a-vis mini-column SPE has been evaluated for preconcentration and cleanup of PACs in their natural matrix, and has been found to effectively remove many polar analytes such as nitrogen containing aromatic heterocyclic compounds, anilines, phenols and certain organophosphorus pesticides. Knitting of tubings created a secondary flow pattern ...


    By Inderscience Publishers

  • Measurement of TOC in High-Salt Sample

    The quantity of organic matter in seawater is important in the research and monitoring of marine pollution as an indicator of organic pollution. The salt content in seawater is typically about 3.5 %, but using the Shimadzu total organic carbon analyzer, it is possible to measure the TOC directly without dilution or other pretreatment procedures. Here, we introduce an example of measurement of ...

  • Effective Groundwater Monitoring Using Dedicated Pumping Tubes

    This article describes a groundwater monitoring procedure that does not require decontamination of pumping equipment, eliminates the chance of cross contamination between wells, and uses a surface pump.  Two surface pumps are described, one for water level depths less than 25 feet and one for water level depths greater than 25 feet. Install Dedicated Pumping Tubes ...


    By RotaPump, Inc

  • A Guide to Gas Detector Tubes. Your Questions Answered

    Gas detector tubes are easy to use, are low cost, and the method is intrinsically safe, allowing it to be deployed in all industries. Because detector tubes don’t require calibration, users see the benefits of this technology over electronic gas detectors due to their ease of ...


    By a1-cbiss

  • Impact of Sampling Media on Soil Gas Measurements

    Abstract To evaluate the vapor intrusion pathway for a building and to assess the associated human health risks, soil gas samples near the building site and under the building foundation may be collected. In order to meet risk assessment goals, the analytical laboratory is often required to report compounds of concern for these soil gas samples down to the part per billion ranges or lower. ...


    By Eurofins Air Toxics Inc

  • Isolate & sample up to 7 zones in one borehole

    CMT Multilevel Systems isolate and monitor up to seven discrete zones in one borehole; monitor 7 zones in the 1.7" (43 mm) System; 3 in the narrow 1.1" (28 mm) System. Both options are low cost. The single tube design makes them fast and easy to drill and install in one day. System flexibility allows port locations and monitoring strategy to be finalized right on site. CMT wells are ideal for ...


    By Solinst Canada Ltd.

  • Evaluating Leaks in a Soil Gas Sampling Train

    ABSTRACT The current advisory for active soil gas investigations in California requires leak tests to be conducted at eveiy soil gas probe while taking a sample. A leak may allow ambient ak into the sample train thus diluting the soil gas and underestimating the results. Also, the leak check compound itself may have impurities thereby contaminating the sample. The advisoiy suggests leak ...


    By Eurofins Air Toxics Inc

  • Monitor Organophosphorus Pesticides in Air, Using ORBO-49P Tubes and Capillary GC

    A sampling tube containing Supelpak-20 resin and a glass fiber filter effectively adsorbs and releases five organophosphorous pesticides (chlorpyrifos, diazinon, dichlorvos, malathion, parathion) in vapor or aerosol form in air.  At a sampling rate of 1L/min, 8 hour samples can be taken for all of these pesticides except malathion.  Short term (15 min) samples can be taken at the same ...


    By Sigma-Aldrich Co., LLC

  • Is the Rotameter Ready for Retirement in Air Sampling/Monitoring Applications?

    The variable area rotameter has been the primary tool utilized for determination of flowrates passing through the air circuitry pathway of air sampling or air monitoring systems for many years. In air sampling applications a pollutant is captured on a collection medium (filter paper, charcoal cartridge, etc.) and taken to a laboratory for determination of the quantity of pollutant on the ...

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