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Diagnostic Methods
Published in Ranjeet Kumar Sahu, Somashekhar S. Hiremath, Corona Discharge Micromachining for the Synthesis of Nanoparticles, 2019
Ranjeet Kumar Sahu, Somashekhar S. Hiremath
The absorption spectra of the colloidal suspension of nanoparticles could be measured at room temperature using a double beam UV-vis spectrophotometer. Figure 3.1 shows the schematic diagram of a double beam UV-vis spectrometer. This spectrometer works in the wavelength range of 190–1100 nm. The spectrometer consists of a light source, diffraction grating, monochromator with a slit, sample holder (i.e. rectangular type quartz-cuvette), series of mirrors, and detector. The light source has two lamps—halogen lamp and deuterium lamp—which give an entire visible spectrum plus the near UV so that the wavelength range of about 190–1100 nm can be covered. A diffraction grating splits the light beam at various wavelengths in different directions. The monochromator with a slit separates and allows the light into a very narrow range of wavelengths that will reach the cuvette containing the sample. The cuvette which contains the sample has an internal width of 10 mm (i.e. path length of 10 mm) and a volume capacity of 3.5 ml.
Spectroscopic Methods
Published in Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus, Environmental Chemical Analysis, 2018
Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus
Samples used in ultraviolet and visible spectroscopy are usually in solution form, although gas-phase measurements can be made using long path gas-tight cells. The sample cells are made of quartz for UV analysis and of glass or plastic for use in the visible region. Round test tubes are often used for low precision work. It is difficult to get a reproducible path length in a round tube, because of slight differences in the placement of the tube in the light beam. It is common practice to mark the tube so that it can be replaced in the spectrometer in the same orientation each time. The tubes used to hold samples and standards can be matched by filling them with an absorbing solution, and selecting the tubes which give the same absorption readings. For more accurate work, cuvettes, which have flat parallel sides are used. These are also available in various materials, and are considerably more expensive than test tubes. Cuvettes are made in various path lengths, with a common size being 10 mm.
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Published in Michael L. Madigan, HAZMAT Guide for First Responders, 2017
Glass use in laboratory applications is not a common place as it once was because of cheaper, less breakable, plastic ware; however, certain applications still require glassware because glass is relatively inert, transparent, heat resistant, and easy to customize. There are several types of glass, each used for different purposes. Borosilicate glass, which is commonly used in reagent bottles, can withstand thermal stress. Quartz glass, which is common in cuvettes, can withstand high temperatures and is transparent in certain parts of the electromagnetic spectrum. Darkened brown or amber (actinic) glass, which is common in dark storage bottles, can block ultraviolet and infrared radiation. Heavy-wall glass, which is common in glass pressure reactors, can withstand pressurized applications.
The Effect of Organic Diluent on the Extraction of Eu(III) by HEH[EHP]
Published in Solvent Extraction and Ion Exchange, 2019
Thibaut Lécrivain, Ashleigh Kimberlin, Devon E. Dodd, Samuel Miller, Ian Hobbs, Emily Campbell, Forrest Heller, Joseph Lapka, Matthew Huber, Kenneth L. Nash
Europium luminescence experiments were conducted to develop spectroscopic evidence of changes in the extracted complex structure in two different diluents (toluene and n-octane). In these experiments an organic solution of 0.1 mol∙L−1 HEH[EHP] was prepared in the required diluent and contacted with a 6 mmol·L−1 Eu(NO3)3 solution (pH = 2 in HNO3). To accommodate the requirements of the fluorimeter, the post-extraction organic solution was diluted by a factor of five (to ~1.2 mmol·L−1 Eu) with the appropriate diluent and then analyzed in a one cm. quartz cuvette. The luminescence spectra were taken on a HORIBA Scientific FluoroMax-4 fluorimeter. The excitation monochromator wavelength was 393 nm with a 14 μm slit width and the emission monochromator was scanned from 550–650 nm with 0.25 nm steps and a 1 μm slit width.
Highly selective and sensitive colorimetric detection of arsenic(III) in aqueous solution using green synthesized unmodified gold nanoparticles
Published in Journal of Dispersion Science and Technology, 2023
K. S. Harisha, B. Narayana, Y. Sangappa
The UV–Visible spectra of the sericin mediated AuNPs were recorded with a Shimadzu UV–3600 UV–Visible spectrophotometer (Japan) in the wavelength region of 200-800 nm. For the measurement samples were taken in a quartz cuvette of 10 mm optical path length.
The influence of the liquid layer height on the velocity field and evaporation during local heating
Published in Experimental Heat Transfer, 2023
S.Y. Misyura, R.I. Egorov, V.S. Morozov, A.S. Zaitsev
To visualize the velocity and temperature fields in the water layer, as well as to measure the evaporation rate, an experimental setup was used; its scheme is shown in Figure 1a. In experiments, a water layer with an initial thickness from 0.6 to 5.1 mm was studied. The diameter (D, Figure 1b) of the layer (the inner diameter of the cuvette) was 7 and 18 mm. The cuvette consisted of 1 mm thick glass. The height of the water layer was determined based on its volume set by the Novus electronic dispenser (from Thermo Fisher Scientific), calculated by the area of the layer base. The measurements used the average diameter value for ten points (different sections passing through the center of the cuvette). The horizontal orientation of the table where the cuvette was located was set with an accuracy of 2–3°. Such a deviation from the horizontal lines did not affect the behavior of the velocity field and, as a result, it was due only to the physical principles and regularities of fluid flow. The unevenness of the initial temperature of the liquid along the circumference of the cuvette did not exceed 2°C. Degassed distillate was used in all experiments. The cuvette surfaces (before the experiments) were cleaned with alcohol and thoroughly washed with distillate. The contact angle of the water droplet on the cuvette surface was 35–40 °. Optical methods, namely, the Particle Image Velocity (PIV) and the Particle Tracking Velocity (PTV), as well as particles of TiO2 (tracers) were used to visualize the velocity field in the horizontal section of the layer. The diameter of the applied particles was 1–2 µm. Various previous studies have shown that TiO2 particles with these sizes allow tracing streamlines quite well and the influence of mass and inertial forces on the measurement of velocity fields may be neglected. The uniform distribution of particles in the layer was achieved by mixing by a magnetic stirrer. The concentration of these particles (tracers) of 6·106 pieces/ml was used in all experiments to measure instantaneous velocity fields. This concentration was chosen experimentally in order to achieve the necessary measurement accuracy (spatial resolution) and uniform distribution of particles by volume, as well as to exclude coalescence and deposition of particles on the glass surface. The optical system (the Navitar ZOOM system with the Thorlabs DCC3240C video camera) allowed using variable magnification. Spatial resolution of the measuring system was up to 2.2 µm/pixel. The maximum magnification mode was 12 µm/pixel, which enabled measuring the velocity fields for almost the entire water layer. An orange glass light filter was used to prevent the camera matrix illumination by scattered laser radiation. The filter eliminated the laser radiation from the visible pictures. The illumination of an array of tracer particles in the measurement area was carried out by the SOLIS-4C LED source.