Quality control of analyses of mercury in hair

Summary Flow injection analysis (FIA) has been combined with a dialysis unit in order to study the effect of interferences in the determination of free cyanide in waste water. Two kinds of interferences, metals and inorganic anions, were studied. In all the cases, solutions of constant cyanide concentration containing interferences were introduced in the FIA system and free cyanide was determined after hydrogen cyanide passes the dialysis membrane.Results reveal the advantages of this methodology for Zn(II), Cu(I), Cd(II), Nr ₄ ⁺ and inorganic anions. Fe(III), Co(II), Ni(II) and carbonate show different behaviour under these conditions.

---

Entfernung von Störungen bei der spektralphotometrischen Cyanidbestimmung unter Verwendung von Dialyse und Fließinjektion

---

Presented at Euroanalysis VI, Paris, September 8–11, 1987     

Discussion on a possible neutrino detector located in India

We have identified some important and worthwhile physics opportunities with a possible neutrino detector located in India. Particular emphasis is placed on the geographical advantage with a stress on the complimentary aspects with respect to other neutrino detectors already in operation.     

Thermal characterization of a nanofluid comprising nanocrystalline ZrO2 dispersed in water and ethylene glycol

Nanofluids, comprising Y₂O₃-stabilized (partially; 3?mol%) ZrO₂ nanoparticles (up to 2?vol%) dispersed in water and ethylene glycol, were developed. A suitable surfactant and stirring routine ensured uniformity and stability of dispersion. Thermal conductivity ratio of the nanofluids, measured using an indigenously developed thermal comparator device, showed a significant increase of up to 100% with only 1.5?vol% nanoparticles. Furthermore, it was analytically shown that shape factor and aspect ratio significantly influence the effective thermal conductivity ratio of nanofluids with comparable vol% nanoparticles. The study demonstrated that a nanofluid of nano-ZrO₂ dispersed in water and ethylene glycol could be usefully applied in closed-loop single-phase heat transfer conditions, such as in refrigerators or microchannels.     

Organic and inorganic discrimination of ballpoint pen inks by ToF-SIMS and multivariate statistics

Surface analysis by ToF-SIMS analysis of ballpoint pen ink markings was performed for discrimination. ToF-SIMS provided non-destructive analysis of ink's organic and inorganic components directly off paper with no interference from the paper substrate. Organic and inorganic information were collected simultaneously and processed with PCA, discriminating 41 out of 45 pairs (91%) of pens analysed. Minimal sample preparation and analysis time, the simultaneous acquisition of organics and metals, and ability to analyse trace amounts gives this technique advantages over others currently utilised in the forensic field. Simultaneous acquisition of organics and inorganics has not been presented before for the characterisation of these materials. It was indicated that pens from the same manufacturer, but discrete batches, can be significantly different.     

Dynamic routing to heterogeneous collections of unreliable servers

We argue the importance of problems concerning the dynamic routing of tasks for service in environments where the servers have diverse characteristics and are subject to breakdown. We propose a general model in which both service times and repair times at each machine are i.i.d.with some general distribution. Routing decisions take account of queue lengths, machine states (up or down), the elapsed processing times of jobs in service and the times to date of any machine repairs in progress. We develop an approach to machine calibration which yields a machine index which is a function of all of the preceding information. The heuristic which routes all tasks to the machine of current smallest index performs outstandingly well. The approach of the paper is flexible and is capable of yielding strongly performing routing policies for a range of variants of the basic model. These include cases where job processing is lost at each breakdown and where the machine state may be only partially observed. AMS Subject Classifications 49L20, 90B22