Studies of chemical speciation in naturally anoxic basins

The chemical speciation of both metals and non-metals, the use of polarographic techniques, and application to the study of the chemistry of anoxic waters are considered. In the first part of the paper unfamiliar terminology is explained and then an example of simple lake chemistry is presented to illustrate why the concept of speciation is necessary

Steady temperature and density distributions in a gas containing heat sources

Computer program, STADDIG, is based on steady state, one dimensional heat transfer calculation using cylindrical coordinates. Program allows for conduction across gas and container walls. Heat is dissipated from walls by forced convection cooling with incompressible coolant. Heat sources are included in coolant, gas, and walls

Treading in Mortimer's footsteps: the geochemical cycling of iron and manganese in Esthwaite water

A study of the geochemical cycling of iron and manganese in a seasonally stratified lake, Esthwaite water is described. This work is based on speculative ideas on environmental redox chemistry of iron which were proposed by C.H. Mortimer in the 1940's. These observations have been verified and some speculations confirmed, along with a new understanding of the manganese cycle, and detailed information on the particulate forms of both iron and manganese. Details on the mechanisms and transformations of iron have also emerged

Axial power tailoring to obtain constant fuel-centerline temperature in a nuclear reactor

Axial power tailoring to obtain constant fuel- centerline temperature in nuclear reacto

A Study on the Control of Third Generation Spacecraft

An overview of some studies which have recently been carried out on the control of third generation spcecraft, as modelled by the MSAT space vehicle configuration, is made. This spacecraft is highly nonsymmetrical and has appendages which cannot in general be assumed to be rigid. In particular, it is desired to design a controller for MSAT which stabilizes the system and satisfies certain attitude control, shape control, and possibly stationkeeping requirements; in addition, it is desired that the resultant controller should be robust and avoid any undesirable spill over effects. In addition, the controller obtained should have minimum complexity. The method of solution adopted to solve this class of problems is to formulate the problem as a robust servomechanism problem, and thence to obtain existence conditions and a controller characterization to solve the problem. The final controller obtained for MSAT has a distributed control configuration and appears to be quite satisfactory

Transmission of Renormalized Benzene Circuits

The renormalization equations emerge from a Greenian-matrix solution of the discretized Schrodinger equation. A by-product of these equations is the decimation process, which enables substituted-benzenes to be mapped onto corresponding dimers, that are used to construct the series and parallel circuits of single-, double- and triple-dimers. The transmittivities of these circuits are calculated by the Lippmann-Schwinger theory, which yields the transmission-energy function T(E). The average value of T(E) provides a measure of the electron transport in the circuit in question. The undulating nature of the T(E) profiles give rise to resonances (T=1) and anti-resonances (T=0) across the energy spectrum. Analysis of the structure of the T(E) graphs highlights the distinguishing features associated with the homo- and hetero-geneous series and parallel circuits. Noteworthy results include the preponderance of p-dimers in circuits with high T(E) values, and the fact that parallel circuits tend to be better transmitters than their series counterparts.Comment: 32 pages, 14 figures, 1 tabl

Simultaneous localization and map-building using active vision

An active approach to sensing can provide the focused measurement capability over a wide field of view which allows correctly formulated Simultaneous Localization and Map-Building (SLAM) to be implemented with vision, permitting repeatable long-term localization using only naturally occurring, automatically-detected features. In this paper, we present the first example of a general system for autonomous localization using active vision, enabled here by a high-performance stereo head, addressing such issues as uncertainty-based measurement selection, automatic map-maintenance, and goal-directed steering. We present varied real-time experiments in a complex environment.Published versio

The control of a nuclear reactor using helium- 3 gas control elements

Control system for water moderated reactor using helium-3 ga