The Shape of Analytical Curves in Zeeman Atomic Absorption Spectroscopy. II. Theoretical Analysis and Experimental Evidence for Absorption Maximum in the Analytical Curve

1980 ◽  
Vol 34 (4) ◽  
pp. 464-472 ◽  
Author(s):  
M. T. C. De Loos-Vollebregt ◽  
L. de Galan
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Stray Light ◽  
Strong Nonlinearity ◽  
Analytical Curve ◽  
Pass Through ◽  
The Magnetic Field

The analysis of the shape of analytical curves in Zeeman atomic absorption spectroscopy has been extended toward higher concentrations. Nonlinearity in the conventional atomic absorption signal due to stray light or nonlinear electronic response causes both theoretically calculated and experimental analytical curves in Zeeman atomic absorption to go through a maximum at a certain concentration. The height and the position of the maximum depend on the magnetic system used, the strength of the magnetic field and the amount of nonlinearity. In all magnetic systems the maximum attainable absorbance is enhanced by increasing the magnetic field strength and decreasing the amount of nonlinearity. Over the normal concentration range a maximum in the Zeeman atomic absorption analytical curve only occurs under the extreme conditions of a very weak magnetic field and strong nonlinearity. Ultimately, however, all Zeeman atomic absorption analytical curves pass through a maximum unless the optics and electronics are perfect. For practical systems strong ac modulated magnetic fields are to be preferred over dc magnetic fields.

The Shape of Analytical Curves in Zeeman Atomic Absorption Spectroscopy. I. Normal Concentration Range

1979 ◽  
Vol 33 (6) ◽  
pp. 616-626 ◽  
Author(s):  
M. T. C. De Loos-Vollebregt ◽  
L. De Galan
Keyword(s):  
Magnetic Field ◽  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Optical Axis ◽  
Variable Magnetic Field ◽  
Constant Field ◽  
Field Sensitivity ◽  
Background Absorption ◽  
The Magnetic Field

Analytical curves have been calculated for different Zeeman atomic absorption spectroscopy (AAS) systems which all correct for background absorption. The sensitivity and curvature of the analytical curves have been compared mutually and to normal AAS. A variable magnetic field is preferred over a constant field. In the variable field sensitivity and curvature are equal to normal AAS whereas in the constant field sensitivity is lower and curvature is stronger compared to normal AAS. Whenever a constant magnetic field is used it should be adjustable to the magnetic field strength where maximum sensitivity is obtained. The magnetic field should be applied to the atomizer to achieve correction for wavelength dependent background absorption. The most promising Zeeman atomic absorption spectrometer employs a variable magnetic field applied to the atomizer and directed parallel to the optical axis.

Synthesis of Ni ferrite and Co ferrite rodlike particles by superposition of a constant magnetic field

2008 ◽  
Vol 23 (6) ◽  
pp. 1764-1775 ◽  
Author(s):  
Fernando Vereda ◽  
Juan de Vicente ◽  
Roque Hidalgo-Álvarez
Keyword(s):  
Magnetic Field ◽  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Potassium Nitrate ◽  
X Ray ◽  
Average Aspect Ratio ◽  
Rodlike Particles ◽  
Dependent Observation ◽  
Lower Saturation

We report the fabrication of micron-sized rodlike particles of nonstoichiometric Co and Ni ferrites by aging coprecipitated Fe(OH)2 and M(OH)2—where M is either Ni or Co—at 90 °C in the presence of an external magnetic field (B ≈ 405 mT). Potassium nitrate was used as a mild oxidant. Resultant particles were analyzed by means of electron microscopy, x-ray powder diffraction (XRD), magnetometry, energy dispersive x-ray (EDX) spectrometry, and atomic absorption spectroscopy. Rodlike particles of both types of ferrite exhibited a relatively uniform thickness, an average aspect ratio close to 10, and have a spinel crystalline structure. EDX spectrometry and atomic absorption spectroscopy confirmed the incorporation of Ni2+ and Co2+ in the respective ferrite particles. The incorporation of Co2+ led to non-negligible remanence and coercivity. The incorporation of Ni2+ led to a lower saturation magnetization, whereas the remanence and coercivity of the Ni ferrite were very low, still typical of a soft ferrimagnetic material. The mechanism of formation of the rodlike particles was investigated by the time-dependent observation of growing Ni ferrite rods.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

DETERMINATION OF ARSENIC, CADMIUM, LEAD, COOPER AND ZINC IN DRINKING WATER FROM R. MACEDONIA

2018 ◽  
Vol 28 (4) ◽  
pp. 1259-1264
Author(s):  
Kiril Lisichkov ◽  
Katerina Atkovska ◽  
Neven Trajchevski ◽  
Orce Popovski ◽  
Nadica Todorovska
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Supply System ◽  
Water Supply System ◽  
Bottled Water ◽  
Cadmium Lead ◽  
The City

The presence of some chemical compounds at higher levels than maximum permissible concentrations (MPC) in the drinking water, suggests of water resources pollution. In this paper the following elements were analyzed: total arsenic, cadmium, lead, cooper and zinc. Twelve samples of water from the water supply system from the city of Skopje were examined during one year from three different springs. Also, ten samples of bottled water from three producers from the Macedonian market were tested.The determined average mass concentrations of total As, Cd(II), Pb(II), Cu(II) and Zn(II) in the analyzed water samples from the water supply system are 1.35 μg/l, 0.06 μg/l, 0.6 μg/l, 0.9 μg/l and 1,12 μg/l, respectively, and for the tested bottled water, the mean values ranges from 0.56 - 0.83 μg total As / l, 0.053 - 0.056 μg Cd(II)/l, 0.51 - 0.54 μg Pb(II)/l , 0.6 - 0.87 μg Cu(II)/l and 0.68 - 0.8 μg Zn(II)/l water.The following instrumental analytical methods and techniques were used for the analysis of the tested samples of drinking water: flame atomic absorption spectroscopy (AAS), atomic absorption spectroscopy with hydride cеll, electrothermal atomic absorption spectroscopy.The obtained results are shown in tables and graphic form. According to the obtained results a comparative analysis was carried out indicate that it is a water of good quality that can be used in different branches of the process industry.The obtained results in this paper do not exceed the values of the MPC of the Republic of Macedonia prescribed by the legal regulations for the drinking water, which confirm the health safety of the drinking water from the water supply system in the city of Skopje and the packed waters from the Macedonian market in relation to the tested elements.

scholarly journals An 84-μG Magnetic Field in a Galaxy at Z=0.692?

2008 ◽  
Vol 4 (S254) ◽  
pp. 95-96
Author(s):  
Arthur M. Wolfe ◽  
Regina A. Jorgenson ◽  
Timothy Robishaw ◽  
Carl Heiles ◽  
Jason X. Prochaska
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Faraday Rotation ◽  
Large Scale ◽  
Dynamo Model ◽  
Magnetic Field Generation ◽  
Interstellar Gas ◽  
Splitting Technique ◽  
Average Value ◽  
The Magnetic Field

AbstractThe magnetic field pervading our Galaxy is a crucial constituent of the interstellar medium: it mediates the dynamics of interstellar clouds, the energy density of cosmic rays, and the formation of stars (Beck 2005). The field associated with ionized interstellar gas has been determined through observations of pulsars in our Galaxy. Radio-frequency measurements of pulse dispersion and the rotation of the plane of linear polarization, i.e., Faraday rotation, yield an average value B ≈ 3 μG (Han et al. 2006). The possible detection of Faraday rotation of linearly polarized photons emitted by high-redshift quasars (Kronberg et al. 2008) suggests similar magnetic fields are present in foreground galaxies with redshifts z > 1. As Faraday rotation alone, however, determines neither the magnitude nor the redshift of the magnetic field, the strength of galactic magnetic fields at redshifts z > 0 remains uncertain.Here we report a measurement of a magnetic field of B ≈ 84 μG in a galaxy at z =0.692, using the same Zeeman-splitting technique that revealed an average value of B = 6 μG in the neutral interstellar gas of our Galaxy (Heiles et al. 2004). This is unexpected, as the leading theory of magnetic field generation, the mean-field dynamo model, predicts large-scale magnetic fields to be weaker in the past, rather than stronger (Parker 1970).The full text of this paper was published in Nature (Wolfe et al. 2008).

Sign in / Sign up

Export Citation Format

Share Document