Assessment of Chemcatcher passive sampler for the monitoring of inorganic mercury and organotin compounds in water

Abstract

Molecularly imprinted polymers (MIPs) for 4-nitrophenol have been successfully prepared by a thermal polymerization method using 4-vinylpyridine (4-VP) and ethylene glycol dimethacrylate (EDMA) as functional monomer and cross-linker, respectively. The obtained materials were evaluated with respect to their selective recognition properties for 4-nitrophenol by HPLC using organic and aqueous eluents. Furthermore, the specific binding sites that have been created during the polymerization process were analyzed via radioligand binding assays. The successful imprinting against 4-nitrophenol provides a new opportunity for advanced separation materials used in environmental analysis.     

The physics of diamond

The accurate measurement of the thermal conductivity of metals still poses considerable experimental difficulty. The reasons for this, and the main ways in which the problem has been approached, are summarized. A detailed examination of the development in technique and methods of measurement shows that while most of the steady-state methods introduced over 50 years ago are still being improved, the emphasis in the last few years has been on the development of methods which give more rapid results, particularly at high temperatures.     

Harmonic renewal measures and bivariate domains of attraction in fluctuation theory

Summary Each probability measure C on a first orthant is associated with a harmonic renewal measure G. Specifically we consider (N, S _N ) the ladder (time, place) of a random walk S _n. Using bivariate G we show that when S ₁ is in a domain of attraction so is (N, S _N). This unifies and generalizes results of Sinai, Rogosin.     

A novel closo-type metallaundecaborane, [1,1-(PPh3)2-2,5-(OEt)2-1-RuB10H8], and its relationship to the ‘isocloso’ series of metallaborane clusters

The new ruthenaundecaborane [(PPh₃)₂RuB₁₀H₈ (OEt)₂] may be considered as an eleven-vertex member of a previously unrecognised series of metallaboranes which are formally derived by the single capping of an arachno-type (rather than a nido-type) cluster geometry with a metal centre which can be thought of as contributing four orbitals to the cluster bonding schemes.     

Expedient synthesis of biologically important sulfonylmethyl pyrimidines

Two novel synthetic strategies that allow rapid diversification of the sulfone moiety in sulfonylmethyl pyrimidines, a class of compounds with a wide range of biological activity, which are of interest in a wide variety of drug discovery programmes, are described.     

A novel approach for the rapid decomposition of Actinide resin and its application to measurement of uranium and plutonium in natural waters

A rapid and robust procedure is described for the decomposition of Actinide resin permitting the routine application of this resin as a preconcentrator. Although the classical Fe(OH)3 precipitation is effective in scavenging actinides, the need for careful handling to recover the sticky precipitate makes the new method much more attractive. The known difficulty of decomposing Actinide resin, which is required prior to the subsequent separation of adsorbed actinides, is innovatively overcome by using a borate fusion attack. This procedure effectively solves the normally encountered problem by safely and speedily decomposing the resin in minutes rather than hours. The alternative and apparently simpler technique of direct ashing of the Actinide resin is not used since it leads to a residue that is not readily leachable. The new technique has been incorporated into a procedure for the isolation of Pu and U from natural water samples and their subsequent quantification by alpha spectrometry. The efficiency of loading of the elements onto Actinide resin has been tested using both batch and column-based approaches. The integrated method involving Actinide resin preconcentration, borate fusion, anion and UTEVA chromatography and electrodeposition provides limits of detection of 0.001 BqL(-1) and chemical recoveries in excess of 80% from groundwater and seawater samples as large as 5L. Comparative data, presented for the analysis of independently analysed river, borehole and surface run-off waters using both the described procedure and other competing techniques, show very good agreement.     

Oscillatory loading of a viscoelastic adhesive contact

The cycle of loading and unloading of a spherically-tipped probe against an adhesive, viscoelastic plane specimen is studied by numerical integration of the relations between crack speed and apparent surface energy previously found for a linear 3-element viscoelastic solid with a Maugis-Dugdale law of force across the crack. It is found that even when the rate of loading is so slow that the loading and unloading curves almost coincide, suggesting purely elastic behaviour, the pull-off force can be appreciably greater than the elastic (JKR) value. When the normal force is modulated with a small amplitude sinusoidal variation during unloading--in order to find the contact stiffness--the contact radius barely changes, and the stiffness is close to that for a rigid flat punch instead of having the expected JKR value.