TL Analysis Research Articles

Lattice Dynamics and Normal Coordinate Analysis of HTSC Tl2CaBa2Cu2O8

The lattice dynamics of the high-temperature superconductor Tl 2 CaBa 2 Cu 2 O 8 has been investigated on the basis of the three-body-force shell model (TSM). The various interactions between ions are treated in a general way without making them numerically equal. The phonon frequency at the zone centre of Brillouin zone are presented and the vibrational assignments are discussed. Further, a normal coordinate calculation has also been employed to study the vibrational analysis of this compound. The normal coordinate analysis of the superconductor Tl 2 CaBa 2 Cu 2 O 8 has been calculated by using Wilson's F-G matrix method which is useful for the confirmation of our present investigation. The vibrational frequencies and the potential energy distribution (PED) of the optically active phonon modes are also presented.

The single-breath transfer factor for carbon monoxide and respiratory symptoms in a Norwegian community sample.

Reduced single-breath transfer factors of the lung for carbon monoxide are seen in a number of conditions. The hypothesis of the present study was that self-reported respiratory symptoms differ in their prediction of TL,CO level in a general population in Norway. A cross-sectional survey of a general population sample in Norway, made up of 1,275 subjects aged 18-73 yrs, was conducted in 1987-1988. The attendees (84% response rate) filled in a questionnaire on respiratory symptoms and underwent standardized spirometric and TL,CO measurements and clinical examination. Associations between TL,CO and respiratory symptoms were assessed using multiple regression models. Tests for interaction were used to examine whether these associations varied with sex, age and smoking habits. Data from 1,221 subjects were analysed. Both males and females who reported respiratory symptoms had significantly lower TL,CO after adjusting for age and height. In a multiple linear regression analysis of TL,CO, adjusting for sex, age, height and smoking habits, the symptoms for which statistical significance was attained, were morning cough, chronic cough and breathlessness. However, only the breathlessness score was independently associated with the TL,CO (-0.42 mmol x min(-1) x kPa(-1) per breathlessness score unit) after adjusting for other respiratory symptoms, and the relationship was stronger in males than in females. In this study, the strongest predictor for a decreased single-breath transfer factor of the lung for carbon monoxide was the presence of self-reported breathlessness, regardless of age, smoking habits and height.

Multidating studies of Batadomba Cave, Sri Lanka

In order to explore the reliability of dating techniques and to determine which materials are most useful for the establishment of precise chronologies, 14C, ESR, TL and OSL analyses were carried out on charcoal, bones. shells and sediments from the archaeological site of Batadomba Cave, Sri Lanka. The dating techniques were complemented by Fourier transform infra-red (FTIR) spectrometry, X-ray diffraction analysis as well as scanning electron microscopy (SEM). Compared with the new and existing charcoal 14C chronology, radiocarbon dating of shells, luminescence dating of sediments as well as ESR dating of shells provided reasonable agreement. Outliers could be explained by diagenetic alteration of the samples. ESR dating of bones seems to he fraught with many complications, but also provided some reasonable age estimates.

The anthracite smokers of eastern Pennsylvania: P s2(g)-T stability diagram by TL analysis : G. B. Stracher, Mathematical Geology, 27(4), 1995, pp 499–511

The anthracite smokers of eastern Pennsylvania: P s2(g)-T stability diagram by TL analysis : G. B. Stracher, Mathematical Geology, 27(4), 1995, pp 499–511

The First Pentahaptofullerene Metal Complexes

Cyclopentadienyl metal complexes have played important roles in chemistry owing to their unique structures and functional activities. Here we report the synthesis and characterization of an entirely new class of cyclopentadienyl (Cp) metal complexes ({eta}{sup 5}-C{sub 60}Ph{sub 5})MLn (MLn = Li, K, Tl, and Cu.PEt{sub 3}). In these molecules, the five Cp carbons represent one pentagon of C{sub 60}, isolated from the remaining 50 sp{sup 2} carbon atoms by five surrounding sp{sup 3} carbon atoms each bearing a phenyl group. The X-ray crystal structure analysis of the thallium complex Tl({eta}{sup 5}-C{sub 60}Ph{sub 5}).2.5THF revealed its unique and esthetically pleasing C{sub 5} symmetrical molecular structure with the phenyl groups forming a chiral propeller array. The thallium atom is deeply buried in the cavity created by the phenyl groups, bonding to the five Cp carbons ({eta}{sup 5}-coordination) with an averaged Tl-C distance of 2.87 A. The key finding that we made in this research was a remarkable 5-fold addition of an organocopper reagent to C{sub 60}, which stands in contrast to the monoaddition reaction of Grignard or organolithium reagents. 10 refs., 1 fig.

The anthracite smokers of eastern pennsylvania: $$P_{S_2 (g)} $$ -T stability diagram by TL analysis

Coal seams and culm banks associated with mine fires in the anthracite region of eastern Pennsylvania have been burning for decades. Many of the fires may have ignited by spontaneous combustion or by the burning of trash. Minerals associated with the combustion of anthracite form by the condensation of gas exhaled through surficial gas vents or “anthracite smokers.” A Pressure-Temperature (P-T) stability diagram is constructed for the condensation of orthorhombic sulfur from anthracite gas using “Thermodynamic Loop Analysis” (TL analysis). This method of analyzing chemical systems incorporates Kirchhoff's Law into a four step procedure structured around a closed thermodynamic cycle or “thermodynamic loop.” The four steps, referred to us “The Four S ′S of Thermodynamic Loop Analysis,” include: (1) “Set Up”—graphical characterization of the problem. (2) “Sum”—the application of thermodynamic principles. (3) “Substitute”—the use of materials data available from the literature, and (4) “Solve”—computation of one or more variables. The example presented demonstrates that thermodynamic loops can incorporate any number of polymorphic phase transformations. In addition, thermodynamic loop analysis is applicable to any geologic process involving the condensation of minerals from a gas. The stability diagram derived by TL analysis may have applicability in monitoring the release of sulfur gas into the atmosphere.

Field determination of thallium in water

A simple, selective, and sensitive field procedure for the spectrophotometric determination of thallium in water is described. The preconcentration is carried out by extracting the chlorothallate ion-pair complex of a cationic surfactant, i.e. CTAB or CPC, with toluene. The extract is reacted with a basic dye, i.e. brilliant green (BG). The molar absorptivity of the complexes is in the range of (1.63–1.70)×105 1 mole−1 cm−1 at the absorption maximum of 640 nm. The detection limit is 5 ng ml−1 Tl in water. None of the tested metal ions upto certain levels interfered with the determination. It is reproducibly applicable to the field analysis of Tl in water samples containing upto 20 ppb.

The biflavones of the cycadales revisited: Biflavones in Stangeria eriopus, Chigua restrepoi and 32 other species of cycadales

The biflavone patterns in leaves of 34 species of the Cycadales representing all of the 11 genera in three families were investigated. Known biflavones were isolated from Gingko biloba and Dioon spinulosum, and then used as internal standards for HPLC and TL analysis of leaf extracts. Biflavone patterns in the new genus Chigua were found to be closely related to those detected in Zamia. Four specimens of Stangeria eriopus were all found to exhibit complex patterns of biflavones. Most members of the Zamiaceae were found to contain hinokiflavone. A first attempt of the chemotaxonomic re-evaluation of biflavone patterns in the Cycadales is made.

A software package for TL/OSL spectrometry and extraction of glow curves from individual grains

A software system has been developed for Macintosh and PC compatible computers running Windows which allows manipulation of time-resolved images collected during TL or OSL analysis of samples. The system utilizes a position-sensitive microchannel plate detector for image capture allowing time encoding for each detected photon. Images may be displayed over specified time/temperature intervals, or may be viewed in entirety in animation mode. Using mouse control, individual grains (1) may be selected for glow curve extraction, (2) may be added to a group of previously selected grains, or (3) may be individually excluded from a larger group of grains. Selected data may be displayed as two dimensional glow curves on screen and may be output in ASCII form for importation into other applications

Cu/Tl-NMR study on Tl-based antiferromagnetic copper oxide TlBa 2YCu 2O 7 (Tl 1212)

Zero-field spectra of the antiferromagnetic Cu-NMR have been observed on the Tl-based copper oxide TlBa 2YCu 2O 7 (Tl1212). The internal field and the electric field gradient at Cu site have been found to be comparable to other antiferromagnetic phase of high- T c oxides. Hyperfine coupling constants of both Cu and Tl sites have been obtained through the analysis of Tl and Cu spectra.

TL analysis of loess samples from achenheim

We have investigated four loess samples from Achenheim. Sample J2a and L1 were collected above and below a horizon with a supposed age of 30 ka. Sample O1 was collected below the last interglacial soil and T1 below the next interglacial soil. For the determination of EDs, the additive dose and regeneration techniques were applied using different filters. The additive dose technique was complicated by the observation that the dose-response could not be described by a single saturation function. We have applied two saturation functions and used only the values below the intercept dose for ED determination. Nearly all calculated ages are younger than expected. Given the uncertainties, there is not a significant difference between results obtained by the additive dose and the regeneration methods. The use of the BG12 and UG11 filters seem to give slightly lower results than the 5–58 filter. We have calculated mean lives for the TL signals of samples L1, O2 and T1 assuming the youngest possible estimates (30, 130 and 240 ka). Our measurements imply that the thermal stability of the recorded signals is somewhere in the 100–200 ka region for the 5–58 filter and around 100 ka for the other filters. Due to the uncertainty of the geological age estimates, these values are more likely upper limits of the thermal stability.

Kinetic Analysis of Natural and Beta-Induced TL in Albite

Kinetic Analysis of Natural and Beta-Induced TL in Albite

Hyperfine structure for some vacuum ultraviolet lines of Tl II and Tl III

The thallium spectrum has been observed in the 1300–2000 Å region using sliding spark and triggered spark excitation sources. Hyperfine structure (hfs) splittings have been reported for 17 Tl II lines and 2 Tl III lines. This leads to the confirmation of the earlier analysis of Tl II in our region of observation. Revised level values for the levels of the 5d106s6p, 5d106s7s, 5d106s6d, and 5d106p2 configurations are also reported. A new value of the hfs constant A for 6s6p 3P1 in Tl II has been reported. Tentative values for the hfs constant A for 6s 2S1/2 and 6p 2P1/2,3/2 in Tl III have been suggested.

ESR dates for the hominid burial site of Qafzeh in Israel

Early modern hominids are found buried at the mouth of a cave at Qafzeh near Nazareth, Israel. They are associated with a Middle Paleolithic lithic industry. Previous dating of this site by TL analysis of burnt flint (Valladas et al., 1988) gave an age of 92 ± 5 kyr. We have now used the ESR method to date enamel of teeth of large mammals from the hominid-bearing layers. Assuming a constant rate of uptake of U through time by the teeth, we obtain an age of 115 ± 15 kyr. This is consistent with the TL results demonstrating early arrival of fully modern humans in Southwestern Asia.

Analytical procedures and clinical reference materials in monitoring human exposures to trace metals with special reference to Cr, Pb and Tl

This paper presents some special guidelines concerning sample collection and handling of clinical specimens for Cr, Pb and Tl analyses. The analytical methods used are briefly discussed. The available clinical reference materials (certified or not) for these three elements are reviewed and future developments are suggested.

Investigation of two copper age cultures by means of TL dating

Abstract During a four-year TL project, the largest Copper Age cemetery in Hungary was studied in detail. Some 26 vessels from 15 graves were investigated by the quartz inclusion technique. Comprehensive TL analyses and evaluation of error limits revealed two distinct periods, corresponding to the Tiszapolgar and Bodrogkeresztur cultures, with TL ages of 6380 ± 160; ± 500 and 5830 ± 100; ± 450 yr, respectively, in agreement with archaeological estimates. The TL methodology and results are discussed and possible interpretations are given.

Beta dose attenuation and calculations of effective grainsize in brick samples

Abstract An assumption commonly made in estimating the beta-ray contribution to individual quartz grains in bricks and tiles is that prior to extraction all grains used for TL analysis existed as discrete grains embedded in a clay matrix. We have found in many Utah brick samples that this assumption does not hold, and that the grains used for analysis were largely derived from clumps or agglomerations of quartz grains of up to 3 mm in diameter. If we apply beta-ray attenuation factors appropriate for the grain sizes actually analyzed (150–250 μm) rather than those appropriate for the agglomerations from which the analyzed samples were derived, errors in measurement of β-ray contribution in excess of 50% can result. We present details of a computer model for determining effective grain size in bricks and tiles based upon microscopic examination of sample sections.

Aminergic Neurotransmitter and Water Content Changes in Rats After Transient Forebrain Ischemia

We have studied changes of cerebral monoamine metabolism and water content, during recirculation following global transient ischemia (20 min) using the four-vessel occlusion model in rats. Levels of monoamines and their metabolites were determined in cortex, striatum, hippocampus, and hypothalamus. Water content was evaluated by weight and by the analysis of T1 and T2 relaxation times in 1H-nuclear magnetic resonance. Norepinephine levels decreased; 3,4-dihydroxyphenylethylamine, 3,4-dihydroxyphenylacetic acid, and 5-hydroxytryptamine levels oscillated and levels of the end products homovanillic acid and 5-hydroxyindole-3-acetic acid increased. The regional changes were qualitatively similar but quantitatively different, and were greatest in the hippocampus, illustrating the concept of neuronal selective vulnerability. The changes suggest an initial monoamine depletion and catabolism due to massive release from stores followed by autoregulatory processes. The water content increased moderately, with a maximum at 1 h. The variations of T1 were similar, positively correlated with water content and more pronounced in the cortex than in the white matter. T2 was markedly altered over the entire 24-h period. Those latter parameters are positively correlated with 5-hydroxytryptamine concentration in the hypothalamus consistent with a relationship between 5-hydroxytryptamine and cerebral edema.

Diagnostic and corrective procedures for TL analysis using the pre-dose technique

The high sensitivity of the pre-dose TL technique using fired quartz grains with relatively low does makes it the only TL technique that is generally suitable for retrospective environmental dosimetry. The use of this technique for dose measurements of less than 0.2 Gy has been the focus of research at the Utah laboratory, while the extension of the useful range of the pre-dose technique to doses in excess of 5 Gy has been the aim of the Durham laboratory. Certain characteristics of the pre-dose phenomenon, if not properly diagnosed, can lead to erroneous dose estimates at both extremes. This paper describes the procedures used at both laboratories to diagnose such problems and recently developed methods for their circumvention.

Carrier Traps in Polyethylene Naphthalate (PEN): Photoelectret

Electronic carrier traps in polyethylene naphthalate (PEN) were investigated by TSC and TL analysis in the temperature range from -196°C to 160°C. Two broad peaks were observed in the TSC and TL from PEN films illuminated with light of wavelength 360 nm at -196°C. The detrapping process was closely related to the molecular motions, the so-called γ and β relaxations. The apparent trap depths ranged from 0.1–0.5 eV.