Measurement Of Liquid Samples Research Articles

Design of resonator cavity for liquid material characterization

Dielectric characterization is very essential before the material can be utilized in designing microwave networks. Circular cylindrical resonators have been widely used for material characterization, but it is not a preferable design during the measurement of liquid samples as the sample placement requires repetitive process of opening and closing the lid of the cavity. This repetition procedure easily affects the accuracy of measurement and may lead to a measurement error. In this study, a rapid and less measurement procedure of liquid material characterization is proposed. The proposed rectangular resonator design is far more convenient and easier to handle as it does not require complex sample preparation. Considering electric field leakage, a hole is designed at the top of the cavity to ease the inserting process of sample. A 5-GHz prototype of a rectangular resonator is designed and fabricated to measure a liquid sample. Complex scattering parameters are measured using a vector network analyzer before the dielectric properties are estimated using an inverse technique. The dielectric properties of distilled water are measured to demonstrate the practicality of the proposed measurement technique. As a result, the measured dielectric properties of distilled water show a reasonable agreement with the values from other literature

Application of a Terahertz System Combined with an X-Shaped Metamaterial Microfluidic Cartridge.

Terahertz (THz) radiation has attracted wide attention for its ability to sense molecular structure and chemical matter because of a label-free molecular fingerprint and nondestructive properties. When it comes to molecular recognition with terahertz radiation, our attention goes first towards the absorption spectrum, which is beyond the far infrared region. To enhance the sensitivity for similar species, however, it is necessary to apply an artificially designed metamaterial sensor for detection, which confines an electromagnetic field in an extremely sub-wavelength space and hence receives an electromagnetic response through resonance. Once the resonance is caused through the interaction between the THz radiation and the metamaterial, a minute variation might be observed in the frequency domain. For a geometric structure of a metamaterial, a novel design called an X-shaped plasmonic sensor (XPS) can create a quadrupole resonance and lead to sensitivity greater than in the dipole mode. A microfluidic system is able to consume reagents in small volumes for detection, to diminish noise from the environment, and to concentrate the sample into detection spots. A microfluidic device integrated with an X-shaped plasmonic sensor might thus achieve an effective and highly sensitive detection cartridge. Our tests involved not only measurements of liquid samples, but also the performance of a dry bio-sample coated on an XPS.

Implementation of three gamma measuring stations on the Colentec loop in Cadarache for the on line observation of the clogging phenomena in Steam Generator

The Tube Support Plate blockage, also named clogging, is a complex phenomenon that can occur in the steam generator of Pressurized Water Reactors. This deposit of iron oxides, that can reduce the coolant flux and constraint the primary tubes, could have significant consequences on heat exchanges and the integrity of the primary tubes. Since 2014, an experimental program carried out jointly by CEA-EDF, has been performed on a representative dedicated equipment, the COLENTEC loop at Cadarache. The physico-chemical properties of the deposit formed (chemical composition, thickness...) were determined at the end of each experimental campaign lead at thermohydraulic and chemical stable conditions. ... In order to determine the influence on clogging of parameters such as the chemistry, the temperature, the pressure in an on line process and without performing separate experimental campaigns, a method of measurement on radioactive tracer, the gamma emitter 59Fe, has been studied by our laboratory. First, a modelization with a monte carlo code, MCNP, has been carried out with the geometrical configuration of the Tube Support Plate zone of COLENTEC in order to determine the most adapted measuring station. These calculations had shown that a 30% efficiency, high purity, germanium detector, with a specific collimation would be able to detect the accumulation of 59Fe in the Tube Support Plate of COLENTEC. Then, in order to improve and ensure those important online measurements, our laboratory has proposed the installation of two additional measuring stations. One will be dedicated to a second on-line measurement, with a gamma detector of the same type, but positioned on a section of the loop remote from the previous area, to verify that there is no significant secondary deposit evolution elsewhere on the circuit. The last additional gamma measurement station will consist of a low background system able to carry out 59Fe concentration measurements of liquid samples taken from the loop during the test. This paper presents the context of this experiment and then focuses on the spectrometry measuring stations, modelizations and tests.

Status of the spent fuel in the reactor buildings of Fukushima Daiichi 1–4

The ratios of the radionuclides Cs-134g and Cs-137 deduced from measurements of liquid samples from the spent fuel pools in Fukushima Daiichi 1–4 are used to interpret the status of the spent fuel assemblies in the pools of the damaged reactor buildings. The different natures of the production of Cs-134g (neutron capture product of Cs-133) and Cs-137 (cumulative fission product from mass chain 137) and the different half-lives (2.06 years and 30.17 years respectively) require a complicated calculation of the mass and activity of the two nuclides. These masses are depending on the local burn up of the fuel, the burn up history and the radioactive decay. Calculation of the neutron capture product Cs-134g is particularly complicated, because the production of Cs-133 (stable cumulative fission product from mass chain 133) has to be taken into account. The neutron capture cross section for Cs-133 for thermal neutrons is well known, but the energy spectrum of the neutrons in a reactor includes higher energies according to the degree of moderation. Therefore the cross section was fitted from a gamma scan of spent fuel rods in a hot cell. The method of the calculation of the nuclide activities and the interpretation of the gamma measurements of the spent fuel pool samples from Fukushima Daiichi 1–4 are described in detail. It could be shown that at most only very minor mechanical damage of some spent fuel elements occurred during the accident and the later phase of the clearing work.

Temperature and Path Length Optimisation for near Infrared Measurement of Liquid Samples: An Alternative Approach

Traditionally, when performing a spectroscopic measurement, temperature and path length are normally set by modifying one factor at a time. This fact means that spectroscopists can be unaware of some possible interaction between these factors and it supposes that a lot of experimental effort is required before inexperienced researchers understand the extent of the variation these may introduce. In this study, experimental design methodology and the subsequent evaluation of results were proposed and applied to this problem in order to make the selection of conditions easier and ensure that it is performed correctly. The present paper is a case study which focused on the selection of path length and temperature for near infrared measurements of vinegar samples from different origins. The main objective was to ensure repeatability between replicates and to make sure that absorbance values in the spectra fell within the linear absorbance range of 0.5–2 au. This paper reports the detection of possible interactions between the factors which can lead to erroneous interpretation of results.

Determination of water in coals by means of proton spin relaxation measurements

The method developed is based on the fact that the initial amplitude of the 1H n.m.r. free induction decay (FID) is proportional to the total number of protons in the sample. The number of protons can be evaluated by comparison with measurements of liquid samples with a known proton concentration. To determine the fraction of water, the total FID signal observed after a single r.f. pulse was decomposed by means of a personal computer. To enable quantitative measurements of protons the FID signal was extrapolated to zero time, which occurs in the centre of the r.f. pulse. The validity of this procedure was checked by comparison with the time evolution of the n.m.r. solid echo signal. The amount of water thus determined was compared with the results of other measurements, i.e. by near-infrared spectroscopy, thermogravimetry, and Karl-Fischer titration. The number of protons belonging to the coal was also measured by this n.m.r. technique and compared with the results from elemental analysis.