SOLON: An autonomous vehicle mission planner

The State-Operator Logic Machine (SOLON) Planner provides an architecture for effective real-time planning and replanning for an autonomous vehicle. The highlights of the system, which distinguish it from other AI-based planners that have been designed previously, are its hybrid application of state-driven control architecture and the use of both schematic representations and logic programming for the management of its knowledge base. SOLON is designed to provide multiple levels of planning for a single autonomous vehicle which is supplied with a skeletal, partially-specified mission plan at the outset of the vehicle's operations. This mission plan consists of a set of objectives, each of which will be decomposable by the planner into tasks. These tasks are themselves comparatively complex sets of actions which are executable by a conventional real-time control system which does not perform planning but which is capable of making adjustments or modifications to the provided tasks according to constraints and tolerances provided by the Planner. The current implementation of the SOLON is in the form of a real-time simulation of the Planner module of an Intelligent Vehicle Controller (IVC) on-board an autonomous underwater vehicle (AUV). The simulation is embedded within a larger simulator environment known as ICDS (Intelligent Controller Development System) operating on a Symbolics 3645/75 computer

Impact specimen geometry on T23 and TP347HFG steels behaviour during steam oxidation at harsh conditions

Ferritic T23 steel and austenitic TP347HFG steel have been studied with an emphasis on understanding the impact of specimen geometry on their steam oxidation behaviour. The selected materials were tested over a wide range of temperatures from 600 to 750°C. The tests were carried out in 100% steam conditions for 1000 hours. The tests indicated that the ‘curved-shaped’ specimens show slower mass gain, scale ticking and void nucleation rates than ‘bridge-shaped’ specimens (with flat and convex surfaces combined). Furthermore, a bridge TP347HFG sample showed the formation of lower amount of flaky oxide at 750°C.We would like to acknowledge the support of The Energy Programme, which is a Research Councils UK cross council initiative led by EPSRC and contributed to by ESRC, NERC, BBSRC and STFC, and specifically the Supergen initiative (Grants GRyS86334y01 and EPyF029748) and the following companies; Alstom Power Ltd., Doosan Babcock, E.ON, National Physical Laboratory, Praxair Surface Technologies Ltd, QinetiQ, Rolls-Royce plc, RWE npower, Siemens Industrial Turbomachinery Ltd. and Tata Steel, for their valuable contributions to the project

Analysis of high temperature steam oxidation of superheater steels used in coal fired boilers

The present work compares the behaviour of four steels: (T23, T92, T347HFG, Super304H) in the temperature range 600–750 °C. This study focuses on the analysis of the oxidation kinetics in terms of mass change, metal loss and thickness change of the selected materials. In order to understand the differences in oxidation rates between the selected steels, the impact of chromium and the alloying elements were considered in this work. The obtained results show that the impact of alloying elements differs with exposure conditions and importance of the synergy effect

Fireside corrosion degradation of ferritic alloys at 600°C in oxy-fired conditions

This paper reports the results of a study carried out to investigate the effects of simulated coal/biomass combustion conditions on the fireside corrosion. The 1000 h deposit recoat exposure (5 × 200 h cycles) was carried out at 600 °C. In these tests ferritic alloys were used 15Mo3, T22, T23 and T91. Kinetics data were generated for the alloys exposed using both traditional weight change methods and metal loss measurements. The highest rate of corrosion based on EDX results occurred under D1 deposit where provoke mainly by the formation of alkali iron tri-sulphate phase

Third-dredge-up oxygen in planetary nebulae

The planetary nebulae He 2-436 and Wray 16-423 in the Sagittarius dwarf galaxy appear to result from nearly twin stars, except that third-dredge-up carbon is more abundant in He 2-436. A thorough photoionization-model analysis implies that ratios Ne/O, S/O and Ar/O are significantly smaller in He 2-436, indicative of third-dredge-up oxygen enrichment. The enrichment of oxygen with respect to carbon is (7 +/- 4)%. Excess nitrogen in Wray 16-423 suggests third dredge-up of late CN-cycle products even in these low-mass, intermediate-metallicity stars.Comment: To appear in Astron. Astrophys. Lett. (Latex, 5 pages, 1 postscript figure

The connection between the papillary muscles and leaflets of the tricuspid valve

The tricuspid valve is more differentiated during evolutionary development than the mitral valve. In birds it is a muscular structure joined directly to the papillary muscles, although the mitral valve of birds resembles that of mammals. There have been well-known studies describing the evolutionary line of connection of the tricuspid valve with the papillary muscles. The present study was performed on a group of 107 formalin-fixed adult human hearts. The valves and papillary muscles were classified according to a scheme for human hearts drawn up earlier. The types of connection between leaflets of the tricuspid valve and the papillary muscles were classified according to a scheme drawn up earlier for vertebrates. We observed 3 types of connection between leaflets of the tricuspid valve and the papillary muscles in the group studied. The muscular and membranous connections were not linked with any one type of tricuspid valve. Atypical forms of distribution of the tendinous chords of the right ventricle were observed. It was found that valves with a higher number of leaflets were (with the exception of type 0) provided with a smaller number of tendinous chords. Atavistic features and atypical forms of distribution of the tendinous chords are present in a small percentage of samples of the human right valvular apparatus

The morphology and distribution of the tendinous chords and their relation to the papillary muscles in the tricuspid valve of the human heart

The tendinous chords of the tricuspid valve are the predominant type of connection between the papillary muscles and the tricuspid valve. Studies describing the evolutionary line of these connections are well known. The flexibility of particular leaflets of the tricuspid valve varies, as does the tension of the blood stream in particular cusps. The present study was performed on a group of 96 formalin-fixed adult human hearts, which ranged in age from 18 to 90 years and gave no evidence of congenital malformations or pathological changes. The valves were divided into five types according to earlier studies and analysis was made in terms of these types. The tendinous chords and their ramifications were counted. The surfaces of particular leaflets were measured. The ratio of marginal to ventricular leaflets was counted for each type of leaflet in particular types of valves. The parts of the main leaflets supported by specific papillary muscles were counted for types 1, 2 and 3. The number of tendinous chords decreased in leaflets in particular types of tricuspid valve, but the ratio of chords attached to the margins and ventricular surfaces was similar. The number of chords for the surface of leaflets (measured in mm2) was similar in particular types of valve for all cusps. The most differentiated were commissural chords in all types of valve. The ratio of chords attached to the margins and ventricular surfaces does not depend on the surface area of the leaflets

The morphology of the right atrioventricular valve in the adult human heart

Studies of the morphometry and normal anatomy of the tricuspid valve are in constant demand. Knowledge of the morphology of the normal tricuspid valve may be useful, for example in the context of the transfer of a leaflet of the tricuspid valve for repair or insufficiency of the mitral valve, in repair of the tricuspid valve after blunt chest trauma and in other surgical techniques of this region. In this study, performed in a group of 107 formalin-fixed adult human hearts, we attempted to assess the form and number of the main and accessory cusps in the tricuspid valve. Rare anatomical variants of the tricuspid valve were found. Using a planimeter we evaluated the surface area of the tricuspid valve and particular leaflets. With the help of a Vernier scale we measured the length and height of individual leaflets of the tricuspid valve and the length of the commissures. No differences were found between the length of the anterior and septal leaflets. The posterior leaflet was the shortest, while the anterior leaflet was the widest and had the largest surface area. The posterior leaflet was wider than the septal leaflet and had the smallest surface area. No differences were found between the main and accessory leaflets in the length of the commissures

Microscopic study of right fibrous annulus

The term annulus fibrous is still used in anatomical and clinical terminology but does not exist in anatomical nomenclature. This structure is proposed as an anatomical substrate for circus movement of excitation. Multiple cardiac damage after blunt chest trauma is rare, but usually affects the septal part of the right fibrous annulus. Histological observation confirms the results of our previous macroscopic study and shows that the most stable part of fibrous annulus is the septal part and the region of anterior angle of the right ventricle, and the most labile parts are the lateral and posterior angles of the right ventricle and the posterior part of the fibrous annulus. Our histological study shows that the right fibrous annulus is a heterogeneous structure and may play a role in changes of shape of the right atrio-ventricular ostium during human life