Rod Analyzers

The carbon rod or carbon tube analyzers offer two distinct advantages over conventional flame methods (1) The sample can be very small, from 1 to 2 ii, and (2) the absolute detection limits are of the order of 10 g for many elements. The carbon rod can be heated to as high as 3000°C, but at this temperature the life of the rod is limited to 20-40 determinations. Light scattering due to incandescent carbon particles also is serious at 3000°C, contributing to a high background. 

One disadvantage of the carbon rod analyzer is the tendency of certain metals, such as barium, strontium, and tungsten, to form refractory carbides at high temperatures. If metal carbides are formed, the metal is removed from the sample vapor and a loss of sensitivity for the metal occurs. 

FIGURE 10-23. The carbon rod analyzer. [From T. S. West and X. K. Williams, Atomic Absorption and Fluorescence Spectroscopy with a Carbon Filament Atomic Reservoir, Anal. Chim. Acta, 45, 26 (1969). Used by permission of Elsevier Press.] 

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Carbon Rod Analyzer, Varian-Techtron model 63 or equivalent. 

In a quadrupole mass analyzer, four parallel rods are arranged equidistantly from a central (imaginary) axis. 

At this point, as far as shaking forces go, the gas forces do not make a contribution. If the rod load or bearing loads are to be analyzed, the gas forces must be calculated and added vectorially to the inertia forces to... 

Many companies now insist that if use of the wrong grade of steel can affect the integrity of the plant, all steel must be checked for composition before use. This applies to flanges, bolts, welding rods, etc., as well as the raw pipe. Steel can be analyzed easily with a spectrographic analyzer. Other failures caused by the use of the wrong construction material are described in Section 16.1. 

This is a letter report from JBF Associates Inc., to Sandia National Laboratories (SNL) summarizing JBF s efforts to analyze dependent (common cause) failures and failures caused by harsh environments. The information used for the analysis was ta)cen from over 1000 failure reports (mostly abstracts of LERs that were assembled for other studies). The 26 groups of components selected for study are accumulators, batteries, cables, control rod drives,... 

EGSG Idaho s Idaho National Engineering Laboratory reviewed Licensee Event Reports (LERs), both qualitatively and quantitatively, to extract reliability information in support of the USNRC s effort to gather and analyze component failure data for U.S. commercial nuclear power plants. LERs describing failures or command faults (failure due to lack of needed input) for selected components have been analyzed in this program. Separate reports have been issued for batteries and battery chargers, control rods and drive mechanisms, diesel generators, ISC, Inverters, primary containment penetrations, protective relays and circuit breakers, pumps, and valves. 

Burn-out data and descriptive details of 24 different rod-bundle geometries, representing all known published work up to 1965, have been compiled and analyzed by Macbeth (M4). Data that have subsequently appeared are given by Matzner (M10), Janssen (J2), Edwards and Obertelli (El), Becker et al. (B11), Moeck (M14), and Hesson (H3). All these data refer to water, and in most of the bundles the direction of water flow is vertically upwards, parallel to the heated rods however, a few tests have also been made with the bundles horizontal, also using parallel flow. Nearly all the experiments have been performed at around 1000 psia, so that the correlation of rod-bundle data must be restricted to this pressure alone. 

We restrict ourselves here to analyzing an extremely simple flexural element, a solid cylindrical rod of radius a and length L, well anchored at one end, and unconstrained at the other end. This is shown in Fig. 1. 

Gelatin behavior in this system indicates that it behaves rod-like that tends to contract with increasing temperature. This conclusion is supported by the observed data from the hydrodynamic properties analyzed. 

We use laser photofragment spectroscopy to study the vibrational and electronic spectroscopy of ions. Our photofragment spectrometer is shown schematically in Eig. 2. Ions are formed by laser ablation of a metal rod, followed by ion molecule reactions, cool in a supersonic expansion and are accelerated into a dual TOE mass spectrometer. When they reach the reflectron, the mass-selected ions of interest are irradiated using one or more lasers operating in the infrared (IR), visible, or UV. Ions that absorb light can photodissociate, producing fragment ions that are mass analyzed and detected. Each of these steps will be discussed in more detail below, with particular emphasis on the ions of interest. 

The quadrupole mass analyzer utilized by Q-ICPMS is comprised of quadrupole rods with combined DC and RF potentials that can be set to allow analyte ions with a specific... 

Transient two-phase flow in rod bundles. In analyzing transient two-phase flows in rod bundles, such as the case resulting from a postulated loss-of-coolant or flow accident in a nuclear reactor, Ishii and Chawla (1978) developed a multi-... 

The objective of this test was to present and analyze suitable experimental results for verif ying quantitatively the use of the above-mentioned three corrections with the W-3 correlation for predicting the DNB heat flux in a rod bundle. Uncertainties in the data due to instrument errors and heater rod fabrication tolerances... 

Rogers and Rosehart (1969) analyzed the data of a number of experimenters and found that they could use Eq. (A-5) to represent the data if c = 0.004. Rogers and Rosehart (1972) later modified their correlation such that for square-pitch rods (adjacent channels with the same De) the flow exchange rate could be represented by... 

Figure 2.15. Schematic of a quadrupole analyzer, (a) A hyperbolic cross-section (b) cross-section of cylindrical rods (c) the operating principle of a quadrupole mass filter. The x-direction pair of rods acts like a high pass filter so ion C (with low m/z) is not allowed through, and the y-direction pair of rods acts like a low pass filter and takes care of ion A (with high m/z). Only ion B having an m/z in the stable range is allowed through the quadrupole mass filter for subsequent detection. Reprinted from A. Westman-Brinkmalm and G. Brinkmalm (2002). In Mass Spectrometry and Hyphenated Techniques in Neuropeptide Research, J. Silberring and R. Ekman (eds.) New York John Wiley Sons, 47-105. With permission of John Wiley Sons, Inc.

The most straightforward tool for the introduction of a sample into a mass spectrometer is called the direct inlet system. It consists of a metal probe (sample rod) with a heater on its tip. The sample is inserted into a cmcible made of glass, metal, or silica, which is secured at the heated tip. The probe is introduced into the ion source through a vacuum lock. Since the pressure in the ion source is 10-5 to 10-6 torr, while the sample may be heated up to 400°C, quite a lot of organic compounds may be vaporized and analyzed. Very often there is no need to heat the sample, as the vapor pressure of an analyte in a vacuum is sufficient to record a reasonable mass spectrum. If an analyte is too volatile the cmcible may be cooled rather than heated. There are two main disadvantages of this system. If a sample contains more than one compound with close volatilities, the recorded spectrum will be a superposition of spectra of individual compounds. This phenomenon may significantly complicate the identification (both manual and computerized). Another drawback deals with the possibility of introducing too much sample. This may lead to a drop in pressure, ion-molecule reactions, poor quality of spectra, and source contamination. 

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