a new cesium ion selective pvc membrane based on parent calix [4] arene was developed for potentiometric determination of cesium in environmental samples. the electrode based on p-5,11,17,23tetra(tertbutyl) 25,26,27,28-tetrahydroxy calix[4]arene(thc) as ionophor ,dibutyl phthalate (dbp)as plasticizer ,sodium tetra phenyl borate(natpb)and oleic acid as lipophilic salt and additive showed the ...

a poly(vinyl chloride) membrane based on a new a-dioxime derivative as membrane carrier was prepared andinvestigated as a cr(iii) selective electrode. the electrode exhibits a good potentiometric response for cr(iii)over a wide concentration range 1.0 x 10-6 to 1.0 x 10-1 m with a slope 19.5+0.5 mv/decade and low detectionlimit of 8.9 x 10-7 m. it has a fast response time < 15 s. the best perfo...

hairsine and rose (1991) developed a process-based soil erosion model which described the erosion transport of multiparticle sizes in sediment for rain-impacted flow in the absence of entrainment in overland flow. in order to test this model laboratory experiments were carried out in a detachment tray using simulated rainfall. three contrasting soil types were subjected to simulated rainfall at...

The present work describes the construction of a new modified electrode by casting the appropriate mixture of a metallocene, which has been introduced in the experimental part, as a mediator at the surface of glassy carbon (GC) electrode. The proposed modified GC electrode was used for the determination of ascorbic acid (AA) in phosphate buffer (PB) solution (pH = 4.0). When compared to bare GC...

There is a dental epidemic occurring literally right under our noses in this country that is largely unrecognized or mis-diagnosed. It is unparalleled in the history of man because of a combination of present day factors that have never existed before, and it is causing widespread damage to the dental health of millions of Americans. Furthermore, it is relatively simple to recognize and there a...

This paper presents a generalized solution to modelling hydraulic erosion using ideas from fluid mechanics. The model is based on the Navier–Stokes equations, which provide the dynamics of velocity and pressure. These equations form the basis for the model to balance erosion and deposition that determine changes in the layers between water and erosion material. The eroded material is captured a...

1Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, 17012-901 Bauru SP, Brazil 2Clinic for Preventive Dentistry, Periodontology and Cariology, University of Zurich, 8032 Zurich, Switzerland 3Department of Cariology and Gerodontology, Faculty of Dentistry, University of Oslo, 0455 Oslo, Norway 4Department of Conservative and Preventive Dentistry, Dental Clinic...

the problems of land degradation and soil loss are among the major problems of watersheds in iran. for erosion andsediment estimation one can use statistical and empirical methods. for doing this, land unit map and the map of effectivefactors should be prepared. for erosion and sediment estimation one can use statistical and empirical methods. however,these empirical methods are usually time co...