(1976). Nuclear Tracks in Solids (Principles and Applications) Nuclear Technology: Vol. 30, No. 1, pp. 91-92.

Nuclear Tracks in Solids (Principles and Applications)

This paper reviews some aspects of solid-state nuclear track detectors (SSNTDs) and their applications in the radon and other research fields. Several geometrical models for the track growth given in the literature are described and compared. It is found that different models give close results for the dimensions of track openings. One of the main parameters that govern track formation is the bulk etch rate Vb. Dependences of Vb on different parameters such as the preparation procedures, etching conditions, irradiation before etching, etc. are examined. A review of existing methods for determination of the bulk etch rate and track etch rate Vt is also given. Examples of Vt functions for some detectors are presented. Some unsolved questions related to Vt and some contradictory experimental results published in the literature are also summarized in the paper. Applications of SSNTDs for radon and progeny measurements are discussed. New designs of diffusion chambers that have appeared in the last few years are portrayed. A review of analytical and Monte Carlo methods for the calculation of the calibration factors in radon measurements is presented. Particular attention has been given to methods of long-term passive measurements of radon progeny with SSNTDs. These measurements are rather difficult and there is not yet a widely accepted solution. One possible solution based on the LR 115 SSNTD is outlined here. Methods for retrospective radon measurements are also described. Various applications of SSNTDs in other fields of physics and other sciences are briefly reviewed at the end of the paper. # 2004 Elsevier B.V. All rights reserved.

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Formation and growth of tracks in nuclear track materials

SUMMARY Cadmium (Cd) is a heavy metal found as an environmental contaminant, both through natural occurrence and from industrial and agricultural sources. Foodstuffs are the main source of cadmium exposure for the non-smoking general population. Cadmium absorption after dietary exposure in humans is relatively low (3–5 %) but cadmium is efficiently retained in the kidney and liver in the human body, with a very long biological half-life ranging from 10 to 30 years. Cadmium is primarily toxic to the kidney, especially to the proximal tubular cells where it accumulates over time and may cause renal dysfunction. Cadmium can also cause bone demineralisation, either through direct bone damage or indirectly as a result of renal dysfunction. After prolonged and/or high exposure the tubular damage may progress to decreased glomerular filtration rate, and eventually to renal failure. The International Agency for Research on Cancer has classified cadmium as a human carcinogen (Group 1) on the basis of occupational studies. Newer data on human exposure to cadmium in the general population have been statistically associated with increased risk of cancer such as in the lung, endometrium, bladder, and breast. Cadmium bioavailability, retention and consequently toxicity are affected by several factors such as nutritional status (low body iron stores) and multiple pregnancies, preexisting health conditions or diseases. A health based guidance value for cadmium of 7 μg/kg body weight (b.w.) per week (Provisional Tolerable Weekly Intake (PTWI)) was established previously by the Joint 1 For citation purposes: Scientific Opinion of the Panel on Contaminants in the Food Chain on a request from the European

/pdf/scientific-opinion-of-the-panel-on-contaminants-in-the-food-4g58bdunry.pdf

Scientific Opinion of the Panel on Contaminants in the Food Chain

Conjugated polymer chains have many degrees of conformational freedom and interact weakly with each other, resulting in complex microstructures in the solid state. Understanding charge transport in such systems, which have amorphous and ordered phases exhibiting varying degrees of order, has proved difficult owing to the contribution of electronic processes at various length scales. The growing technological appeal of these semiconductors makes such fundamental knowledge extremely important for materials and process design. We propose a unified model of how charge carriers travel in conjugated polymer films. We show that in high-molecular-weight semiconducting polymers the limiting charge transport step is trapping caused by lattice disorder, and that short-range intermolecular aggregation is sufficient for efficient long-range charge transport. This generalization explains the seemingly contradicting high performance of recently reported, poorly ordered polymers and suggests molecular design strategies to further improve the performance of future generations of organic electronic materials.

http://absimage.aps.org/image/MAR14/MWS_MAR14-2013-020288.pdf

A general relationship between disorder, aggregation and charge transport in conjugated polymers

Optical properties of pure polyvinyl alcohol (PVA) and PVA based nanocomposite films have been investigated. The nano-composite samples were prepared by the well known solution cast method. The experimental results shows that the absorption and absorption coefficient parameters are greatly affected by variation of copper oxide (CuO) nanoparticles concentration. The absorption versus wavelength for the doped samples is exponential while the absorbance of pure PVA is sharply varied with wavelength. An obvious surface plasmonic resonance peaks for the nano-composite samples were appeared. The absorption edge was greatly shifted to lower energy for the PVA doped samples. It was observed that optical band gap of pure PVA is significantly reduced upon the addition of CuO nanoparticles. The increase of refractive index with increasing CuO concentration is an evidence for the formation of new energy states and thus decreasing the energy band gap of PVA. The increase of optical dielectric constant was observed upon the addition of CuO nanoparticles. The optical dielectric loss peaks are shifted to higher wavelength with increasing the CuO concentration. The optical conductivity is increased upon the addition of CuO nanoparticles. The dispersion region in the refractive index spectra are well obeyed the single oscillator of the Wemple–Didomenico model for all the samples.

Reducing the optical band gap of polyvinyl alcohol (PVA) based nanocomposite

Natural activities of , and in some Indian building materials

Study of uranium, radium and radon exhalation rate in soil samples from some areas of Kangra district, Himachal Pradesh, India using solid-state nuclear track detectors

Electrical and Optical Properties of O6+ Ion Beam–Irradiated Polymers

The study of indoor radon in dwellings of Bathinda district, Punjab, India and its correlation with uranium and radon exhalation rate in soil

In present study, Zinc Ferrite-Alginate beads (ZFN-Alg beads) were prepared and characterized by Fourier Transform-Infra Red (FT-IR); X-Ray Diffraction (XRD); Scanning Electron Microscope (SEM); Energy Dispersive Spectra (EDS); Thermogravimetric-Differential Thermal analysis (TG-DTA); Brunauer-Emmett-Teller (BET) and pH point zero charge (pHPZC) method. The adsorption of Pb(II) and Cu(II) ions on ZFN-Alg beads as function of contact time, varying pH, adsorbent dose, initial concentration at different temperatures were investigated in single as well as binary system through batch mode. The adsorption kinetic data of Pb(II) and Cu(II) ions in both type of systems was well followed by the Lagergren pseudo second order model. Among different isotherm models, the equilibrium data was well correlated by Langmuir isotherm model in single as well as binary system. In single system, the maximum adsorption capacities of Pb(II) and Cu(II) ions for ZFN-Alg beads were 108.8, 106.6 mg/g and for binary system were 68.6 and 48.0 mg/g, respectively. For both types of systems, the calculated adsorption thermodynamic parameters indicated that the adsorption process was spontaneous and exothermic in nature. The regeneration performance of ZFN-Alg beads was examined in both types of systems up to five cycles. The results revealed that ZFN-Alg beads were retained around 80% regeneration efficiency even after five successive cycles in both types of systems. The present study concluded that magnetic biopolymer beads might be suitable and cost effective alternative for removal of Pb(II) and Cu(II) metal ions from single as well as binary system.

Mukesh Kumar

Papers

Natural activities of , and in some Indian building materials

Study of uranium, radium and radon exhalation rate in soil samples from some areas of Kangra district, Himachal Pradesh, India using solid-state nuclear track detectors

Electrical and Optical Properties of O6+ Ion Beam–Irradiated Polymers

The study of indoor radon in dwellings of Bathinda district, Punjab, India and its correlation with uranium and radon exhalation rate in soil

Removal of lead and copper metal ions in single and binary systems using biopolymer modified spinel ferrite