Cellular Automata Models of Traffic Behavior in Presence of SpeedBreaking Structures

In this article, we study traffic flow in the presence ofspeed breaking structures. The speed breakers are typically used toreduce the local speed of vehicles near certain institutions such asschools and hospitals. Through a cellular automata model we study the impact of such structures on global traffic characteristics. The simulation results indicate that the presence of speed breakers could reduce the global flow under moderate global densities. However, under low and high global density traffic regime the presence of speed breakers does not have an impact on the global flow. Further the speed limit enforced by the speed breaker createsa phase distinction. For a given global density and slowdown probability, as the speed limit enforced by the speed breaker increases, the traffic moves from the reduced flow phase to maximum flow phase. This underlines the importance of proper design of these structures to avoid undesired flow restrictions.     

Positive Definite Functions and Operator Inequalities

We construct several examples of positive definite functions,and use the positive definite matrices arising from them toderive several inequalities for norms of operators. 1991 MathematicsSubject Classification 42A82, 47A63, 15A45, 15A60.     

Purification of 233U from Thorium and Iron in the Reprocessing of Irradiated Thorium Oxide Rods

A two step precipitation using ammonium carbonate and oxalic acid as the precipitants for thorium and iron is developed for the purification of ²³³U. Ammonium carbonate is added to the feed to increase the pH of the solution. The effect of pH on the solubility of U, Th and Fe in an excess of ammonium carbonate is studied. This indicates that the solubility of Th and Fe is minimum at pH 7 and the recovery of uranium is maximum. The effect of the concentration of thorium and iron on the recovery of uranium at pH 7 is studied. This indicates that the ammonium carbonate precipitation tolerates 2 g/l of thorium and 10 g/l of iron keeping losses of uranium to a minimum. If the feed solution contains more than a tolerable concentration of thorium the precipitation is followed in two steps: (1) Bulk of the thorium is removed by oxalate precipitation, (2) the remaining thorium and iron in the supernatant are removed by ammonium carbonate precipitation. A flow sheet is proposed for the purification of ²³³U from thorium and iron present in a strip product concentrate obtained during the reprocessing of irradiated thorium rods.     

Theoretical evaluation of the overall values of Booth type R-indices based on intensity variables

Theoretical expressions for the overall values of three Booth type R-indices based on intensity variables are derived. The results are applicable to crystals of any space group containing any number and type of atoms at general positions in the asymmetric unit. The theoretical results were tested in the case of models of a few crystal structures.     

Radiochemical neutron activation analysis of individual rare earth elements in monazites from different geological environments

Radiochemical neutron activation analysis /RNAA/ has been applied for the determination of individual rare earth elements /REE/, except Tm, in 8 Indian monazites and one each from Malaysia and Thailand. Because of the very low amounts of heavy rare earths /HREE/ compared to light rare earths /LREE/ in monazite, HREE from Ho onwards have been determined only after the separation of the heavy and light rare earth fractions in the irradiated monazite samples. The results indicate significant variations in REE contents from Eu to Lu among different monazite samples. The chondritic normalized REE patterns of all the samples show a prominent negative Eu anomaly with different slopes at the heavy rare earth end. All the individual REE, except Tm, have been reported for the first time in various Indian monazites.     

Instanton induced chiral symmetry breaking in extended QCD model

A mechanism for instanton induced chiral symmetry breaking in an extended QCD model (QCD with fundamental scalars) is proposed to describe quarks and gluons inside a baryon. The model Lagrangian that we use has the same symmetry properties as QCD. The scalar fields are shown to develop vacuum expectation values in the instanton background and generate masses for the three generation of quarks. The minimization condition is also used to break the flavour symmetry to make the -quark heavier that the and quarks. Received: 16 August 1996 / Revised version: 15 October 1997 / Published online: 26 February 1998     

An extremal problem in geodetic graphs

An upper bound for the number of lines in a geodetic block of diameter d on p points is obtained, using some new general properties of geodetic blocks which are also of independent interest.     

A study of the behaviour of solid-state membrane electrodes: Part IV. Experimental studies of the response time

Some ot the factors governing the response time of the fluoride-selective and chloride-selective electrodes have been investigated. The results of E—t and conductance measurements indicate that dissolution and charge-transfer processes control the ion-seiective electrode kinetics. The temperature coefficients of the rate constants for dissolution of the chloride electrode membrane, determined by E—t curves and conductimetric measurements, are similar. The results, and the fact that the dissolution is a second-order process, indicate that surface processes play the predominant role in electrode kinetics near equilibrium.