Multi-element System Research Articles

Thermospray liquid chromatography—mass spectrometry with a quadrupole ion trap mass spectrometer

A thermospray ion source using corona discharge ionization was interfaced to a quadrupole ion trap mass spectrometer via a multi-element lens system. Ions were injected into the trap periodically where they were stabilized by collisions with helium bath gas. Mass spectra were recorded on the trapped ions using the mass-selective instability scan mode. Data are shown for a peptide and a nucleoside and the effects of some experimental variables on the spectra are explored.

Neutron radiography with the cyclotron (VII): image restoration using the three-dimensional local matrix : Taniguchi, R.; Hiraoka, E.; Sonoda, K. Ono, A.; NAkanii, T. Annual Report of Osaka Prefectural Radiation Research Institute, Vol. 29, pp. 49–54 (1989)

This work describes the performance of an ultrasonic imaging scheme suitable for operation in a low signal to noise ratio environment. Based around a series of dedicated correlators, a multi-element system suitable for on-line array applications is described in conjunction with potential imaging and image processing strategies. A selection of experimental results is included to verify the potential of the overall approach. Although designed specially for those applications in which peak energizing powers are limited, the basic strategy is suitable for a wide range of applications that are limited by the available signal to noise ratio. These include ultrasonic non-destructive evaluation of attenuating materials, airborne ultrasonic imaging, intrinsically safe inspection and biomedical investigation.

Ultrasonic NDE (Nondestructive Evaluation) of Kevlar-epoxy filament wound spherical pressure vessels : Balke, R.A.; Steiner, K.V. Oak Ridge Y-12 Plant, Tennessee (United States) DE89-1976, 45 pp. (Oct. 1985)

This work describes the performance of an ultrasonic imaging scheme suitable for operation in a low signal to noise ratio environment. Based around a series of dedicated correlators, a multi-element system suitable for on-line array applications is described in conjunction with potential imaging and image processing strategies. A selection of experimental results is included to verify the potential of the overall approach. Although designed specially for those applications in which peak energizing powers are limited, the basic strategy is suitable for a wide range of applications that are limited by the available signal to noise ratio. These include ultrasonic non-destructive evaluation of attenuating materials, airborne ultrasonic imaging, intrinsically safe inspection and biomedical investigation.

Development of a novel multi-element detection system for trace metal determination based on chemiluminescence after separation by ion chromatography

A highly sensitive, non-selective trace metal detector based on chemiluminescence has been developed. The metals, separated by simple ion-exchange chromatography, bring about the displacement of cobalt from a Co-EDTA post-column reagent. The liberated cobalt is then detected by the luminol-peroxide chemiluminescence reaction using a modified spectrofluorimeter as the detector. The metals determined are Mg, Ca, Sr, Ba, Fe(II), Fe(III), Co, Ni, Cu, Zn, the lanthanides, Th, Al, Ga, In, Pb and Bi. The detection limits (three times the baseline noise) range between 2 and 100 μg l −1, depending on the analyte, for a 200-μl injection. To demonstrate the quantitative performance of the detector, the zinc and aluminium contents of a fresh water certified reference material was determined and gave good agreement with the certificate values.

Performance of a multi-sector ultrasound hyperthermia applicator and control system:in vivostudies

A multi-element ultrasound hyperthermia system (Labthermics Technologies, Inc., Sonotherm 1000) was utilized to deliver energy to two relatively well-defined regions (3.8 X 3.8 cm) on the lateral aspect of the right rear leg of 22 dogs in 1, 2 and 3 weekly treatments to a target temperature of 42-43 degrees C, at a depth of 1 cm. The total treatment time was 30 min. One area heated on each dog was adjacent to the proximal femur and the other was 2-3 cm away from the distal aspect of the same bone. The system performed in an acceptably controlled manner and was able to deliver energy to a well-defined site. The mean temperature achieved, and rate of temperature rise in the heated regions, was independent of the region being treated. Little difference (0.12 degrees C) was noted between the mean temperatures of the heated regions, and the temperature bounds (42-43 degrees C) were exceeded by a small amount and for a relatively short period of time (out of range RMSE = 0.6 degrees C). Unheated regions showed much lower mean temperatures than did heated regions located 3.8 cm away, indicating that the energy was delivered in a well-defined manner. Superficial thermal injuries occurred in three of 22 dogs in the area heated 2-3 cm away from bone, and 11 of 22 dogs exhibited injuries in the tissue heated immediately adjacent to the femur.

Clinical experience with a multi-element ultrasonic hyperthermia system: Analysis of treatment temperatures

A summary of tumour temperature data obtained from 31 patients who underwent 147 hyperthermia treatments with the Sonotherm 1000 ultrasonic system is presented. The treatment goal was to achieve a minimum of 42.0 degrees C in tumour for 60 min duration with normal tissues remaining below 43.0 degrees C. In 83% of treatments at least one measured tumour temperature reached or exceeded 42.0 degrees C at some time during the treatment. Nineteen per cent of these treatments had a time- and spatial-averaged temperature (measured in tumour) greater than or equal to 42.0 degrees C. A variety of anatomical sites were treated and these were grouped into four categories: groin/trunk, axilla, breast/chest wall and head/neck. Measured temperatures in tumours located in the groin and trunk sites were significantly higher (22% greater than or equal to 42 degrees C) than other locations. The head and neck treatment temperatures were significantly lower (8% of measured points greater than or equal to 42 degrees C.

Low power ultrasonic imaging using digital correlation

This work describes the performance of an ultrasonic imaging scheme suitable for operation in a low signal to noise ratio environment. Based around a series of dedicated correlators, a multi-element system suitable for on-line array applications is described in conjunction with potential imaging and image processing strategies. A selection of experimental results is included to verify the potential of the overall approach. Although designed specially for those applications in which peak energizing powers are limited, the basic strategy is suitable for a wide range of applications that are limited by the available signal to noise ratio. These include ultrasonic non-destructive evaluation of attenuating materials, airborne ultrasonic imaging, intrinsically safe inspection and biomedical investigation.

Life and failure of systems of glass shells in complicated static and quasidynamic loading

The effect of the scale of shells on the resistance to avalanche failure of multielement systems in the conditions of complicated loading with uniform pressure and a hydraulic pulse is examined.

Aperture efficiencies of large axisymmetric reflector antennas fed by conical horns

It is shown how the radiation patterns of conical horns can be understood in terms of Laguerre-Gaussian beam modes. This approach provides a simple method for calculating the horn radiation pattern as it propagates through a multielement optical system consisting of lenses or offset mirrors with large focal ratio and/or a small angle of incidence, and can be used in quantitatively determining aperture efficiencies for systems where conical horns are coupled to antennas via tertiary optics. The resulting aperture efficiency results and a practical quasioptical system fed by a conical horn are discussed. >

Two-quasiparticle bands in72Br

High spin states in the doubly odd nucleus72Br were investigated via the reaction58Ni(16O,pn) at 52–65 MeV beam energy. A multi-element detector system consisting of ten Compton supressed Ge detectors (OSIRIS) and two NE213 neutron detectors was used to establish the yrast bands up to 5 MeV excitation energy and probable spins of 15+ resp. 14−. The lifetimes of 12 states and lifetime limits of four states were measured with the recoil distance method, among them four 0.5–3.1 ns isomers. Doppler broadened line shapes obtained in an additionalγγ-coincidence experiment via the reaction40Ca(36Ar, 3pn) at 125 MeV revealed further lifetimes and (very short) side feeding times. Three rotational bands were established with deformation parameters ¦β2¦≈0.3 and moment of inertia parameters\(\tilde f\)/ħ2=36 MeV−1 (Kρ=1−) resp. 23 MeV−1; their quasi-particle configurations are being discussed.

A Simplex Optimized Inductively Coupled Plasma Spectrometer with Minimization of Interferences

Several figures of merit are considered as criteria to optimize an ICP atomic emission spectrometer for quantification of multielement systems. A criterion is proposed and evaluated that will establish optimum analysis conditions with minimization of spectral interferences. The optimization scheme makes use of the variable step-size simplex technique.

Hot-wire measurements of velocity and temperature fluctuations in a heated turbulent boundary layer

Describes the development of a multi-element hot-wire anemometry system designed to measure the fluctuating velocity and temperature in non-isothermal boundary layer flows. This system utilised only standard constant-temperature anemometers and commercially-available sensors. Although the maximum frequency response for the present system was limited by the available signal digitisation rates the probe-anemometry combination itself was shown to be capable of resolving signals to approximately 50 kHz. The performance of the system was evaluated by comparing velocity and temperature statistics measured in an equilibrium turbulent boundary layer flow with similar results from other investigations.

医療における人体磁界測定の有効性 心磁図の効力

Action current of the heart muscle produces electric field on the body surface and also weak magnetic field around the thorax. Magnetocardiogram (MCG) is a record of this magnetic field by means of a very sensitive magnetometer. We usually record MCG at 36 points of the anterior chest wall by means of a SQUID with the transducer coil for the second gradient of the magnetic field. Electrocardiography has been used widely for the diagnosis of the cardiovascular diseases, but its limitations have also been known. MCG can not be expected to provide different kinds of informations from ECG, because both methods handle such informations related to the electromotive forces of the heart. But there may be some possibility that the MCG can give some diagnostic informations which can not be detected by ECG, because the magnetism is somewhat different from electricity in physical properties. For example diagnostic sensitivity of the right atrial overloading is 13.6% in ECG and 56.6% in MCG, showing higher diagnostic ability of MCG. As for the diagnosis of the right ventricular hypertrophy, diagnostic sensitivity is 31.3% in ECG and 73.3% in MCG, also showing the higher sensitivity in the latter than the former. Sensitivity for the diagnosis of the myocardial damage (abnormal ventricular repolarization) in hypertensive subjects was 20.0% in ECG and 42.5% in MCG. Sensitivity is especially higher in MCG in slight to moderate cases of hypertension. Multiple dipoles were detected in 7.5% in isopotential map and 27.5% in isomagnetic map at the peak of the T wave in lead II of the standard leads. The reason of the higher sensitivity of MCG for the diagnosis of the abnormal ventricular repolarization is thought to be due to the superiority of MCG in detecting multiple dipoles. At present, liquid helium is necessary to record MCG, and the multi-elements MCG system are not available with a reasonable price. It is expected that the MCG may become to be used widely in clinical medicine as a supplementary diagnostic method to the ECG, if these weak points are overcome.

An evaluation of regional elemental signatures relevant to the Northeastern United States

Concentrations of sulfate and trace elements measured in high-volume air samples collected at sites in New York State during the summers of 1981, 1982 and 1983 are reported. The sites include Mayville in the westernmost corner of the state, West Haverstraw just north of the metropolitan New York area, and Whiteface Mountain in the Adirondacks. The elemental compositions of the aerosols at these sites are compared. The composition of regional aerosols is investigated using backward-in-time air trajectories to classify samples from Mayville and West Haverstraw into six regions: I, southern Ontario; II, Great Lakes; III, Ohio River Valley; IV, central Pennsylvania; V, western New York; and VI, East Coast urban. Region VI was characterized by high concentrations of V and Sb and relatively low concentrations of the other elements and sulfate. Region III had the highest concentrations of sulfate (28 μg m −3) and Se (5 ng m −3); both were around 7.5 times higher than for region VI. Crustal elements and bromine were comparable for all regions varying by a factor of two or less. Elemental ratios were explored as tracers for the various regions and the data are also used to test some of the basic assumptions in a proposed multi-element tracer system.

Potential-pH diagrams for complex systems

A generalized thermodynamic analysis and a geometric interpretation of potential-pH diagrams for multi-element systems are presented. The presence of reactive gases, e.g. CO2 and SO2, and complex-forming species, e.g. NH3 and Cl−, are expressly considered. The equilibrium state is described by a set of independent formation reactions of all species containing the active redox element, M. The formation reactions are written in terms of a user-specified set of primitive species, e.g. M, H2O, H+,e, X and Y, where X and Y could be CO2 and Cl− for example. Some of these primitive species, e.g. M ande, may be virtual species, that is, they do not have an independent existence as separate entities in the reaction mixture. This procedure permits an explicit algebraic solution for the potential-pH diagram. Examples of Pourbaix and predominance diagrams for complex uranium and chromium systems are given.

Mixed Field Multi-Element Beta/Gamma Dosemeter Design

Abstract A multi-element TLD badge system has been designed for use with a Teledyne Isotopes TLD system. The badge contains four areas, each with its unique filtration, to allow discrimination between beta and gamma contributions at the various energies present in a mixed radiation field. The active TL element in the badge consists of CaSO4:Dy embedded in Teflon. Filtration from three filter elements allows energy and radiation discrimination in the badge. These filters are designed as follows: (a) a beta shield to filter out 97% of the incident betas; (b) a gamma energy compensation filter to allow dose determination for photon radiation of all energies; and (c) a bias filter to record all high energy photons. Doses recorded by the TL element under each filter are compared with the total dose recorded under an open window. Intercomparisons of recorded doses from these four areas then allow both beta-gamma discrimination and gamma energy discrimination.

Promoters for the liquefaction of wet Victorian brown coal in carbon monoxide

Sodium aluminate and sodium silicate have been found to be useful as promoters for the reaction of brown coal with carbon monoxide and water. Promoters such as sodium aluminate have been shown to behave effectively as a two-component system. The first component involves the sodium aluminate behaving as a mild base interacting with acidic groups in the coal. This role can be adopted by other basic salts (acetate, hydroxide, carbonate, etc.) of other alkali metals which have been found to be effective in the order Cs > K > Na > Li. The second component of the sodium aluminate system is an alkali metal ion doped alumina, whose role in the liquefaction is unclear but may involve the generation of strong Lewis base sites on the alumina which can facilitate one electron transfer reactions leading to radical stabilisation. These systems also catalyse the production of hydrogen by the water gas shift reaction but this has been shown not to be an essential feature of their action as magnesium acetate, which does not promote the water gas shift reaction, shows similar promoter activity. When these catalyst systems are combined with those traditionally active in promoting the reaction of coal with hydrogen (e.g. Cu, Ni, Co) new multi-element promoter systems are obtained which are particularly effective for promoting the reaction of brown coal with synthesis gas (CO + H 2) and water.

An improved interface for inductively coupled plasma-mass spectrometry (ICP-MS)

Adiabatic sampling of the plasma from an inductively coupled plasma (ICP) torch is a crucial first step for inductively coupled plasma-mass spectrometry (ICP-MS) to reach its full potential as a trace multi-element analysis system. Previous results in the literature are reviewed, and a series of experiments reported, which indicate that a discharge, previously called a “pinch” effect, can be present in which the plasma properties are strongly altered by a constricted current flowing between the plasma and the sampling orifices, i.e. a secondary discharge. Measurements and calculations indicate that this mechanism is consistent with previously reported deleterious effects—abnormal production of doubly ionized species, a wide kinetic energy distribution for the ions sampled into vacuum, formation of ions from metal eroded from the sampling orifices, and a decreased orifice life-time. The mechanism producing the effect was found to be an unwanted capacitive coupling between the voltage on the induction coil and the plasma. Results are included which show that by centre-grounding the coil, the “pinch” effect can be reduced to negligible proportions. The resulting improvements for ICP-MS operation are described.

Extraction of molybdenum with a multielement liquid organic extraction system

An extraction of molybdenum is described that provides a more predictable separation over a significantly wider acidity range than previously determined. The extraction of Mo appeared to be a function of HCl normality, with virtually complete separation above 3.6 N. A test was conducted to determine if the extraction was a function of just HCl concentration or of overall acidity. When the aqueous phases of the test sequence were all prepared at 1 N H/sub 2/SO/sub 4/ in addition to the HCl in each, the resulting extraction curves were essentially identical. Another test was performed to determine if Mo was being extracted as an iodide complex. Three aqueous solutions, which were 4 N in HCl and 26% (w/v) ascorbic acid, were prepared in culture tubes. When 25 ..mu..g of Mo was extracted from these solutions of 5 mL of organic phase, the KCl gave only a 16% extraction, the KBr gave only a 22% extraction, and the KI provided an essentially total extraction. 4 references, 1 figure.

A figure of merit for signal processing reflector antennas

In recent years a new class of reflector antennas utilizing array feeds has been receiving attention. An example of this type of antenna is a reflector utilizing a moveable array feed for beam steering. Due to the circuitry required to adjust the weights for the various feed array elements, an appreciable amount of loss can be introduced into the antenna system. One technique to overcome this possible deficiency is to place low noise amplifiers with sufficient gain to overcome the weighting function losses just after each of the feed elements. In the evaluation of signal processing antennas that employ amplifiers the standard antenna gain measurement will not be indicative of the antenna system's performance. In fact, by making only a signal measurement, the antenna gain can be made any arbitrary value by changing the gains of the amplifiers used. In addition, the IEEE Standard Test Procedures for Antennas does not cover the class of antennas where the amplifier becomes part of the antenna system. There exists a need to establish a standard of merit or worth for multi-element antenna systems that involve the use of amplifiers. A proposed figure of merit for evaluating such antenna systems is presented.