Showing papers by "King's College, Aberdeen published in 1996"
TL;DR: In this article, a ground-penetrating radar survey of aeolian dunes in the Al Liwa area of Abu Dhabi reveals a variety of dipping reflectors which are interpreted as primary sedimentary structures.
Abstract: A ground-penetrating radar survey of aeolian dunes in the Al Liwa area of Abu Dhabi reveals a variety of dipping reflectors which are interpreted as primary sedimentary structures. The interpretation of the radar profiles has been confirmed by bulldozing trenches through the study area and comparing logged sections in the trenches with the radar profiles. NNW— SSE-orientated radar profiles, approximately parallel to the prevailing wind direction, show two sets of dipping reflectors which are interpreted as sets of cross-stratification and second- and third-order bounding surfaces. Radar profiles orientated WSW—ENE across the prevailing wind direction are dominated by concave-up reflectors which are interpreted as trough-shaped scours and sets of trough cross-stratification produced by oblique progradation of barchanoid dunes. Nested troughs, with small sets of trough cross-stratification within larger troughs, may be due to reactivation following wind reversal, or the superposition of small dunes on larger dunes and the fill of large dune troughs by smaller dunes. Convex-upwards reflectors are interpreted as linear spurs on the convex portions of sinuous dunes or erosional remnants between troughs. Overall there is a tendency for the larger second-order bounding surfaces to dip downwind, which confirms Brookfield's ideas of the relative migration paths of dunes and draa.
118 citations
TL;DR: It is suggested that a range of forms of mentoring were perceived as valuable by different groups of young people and from these a typology of Mentoring forms is devised.
73 citations
TL;DR: In this article, the Arrhenius parameters of two Scottish bituminous coals were determined from heat-release rate measurements at laboratory oven temperatures, and one coal was shown to have a significantly greater propensity to spontaneous combustion than the other.
64 citations
TL;DR: In this article, a single relaxation time model describing the kinetics of enthalpy relaxation has been applied to modulated differential scanning calorimetry (MDSC) in the glass transition region.
47 citations
TL;DR: In this article, the authors demonstrate that early calcite cement contains <2 mol% MgCO3, despite its marine parentage, and that the calcite probably precipitated from marine pore fluids shortly after turbidite deposition.
Abstract: Lower Cretaceous (Hauterivian) bioclastic sandstone turbidites in the Scapa Member (North Sea Basin) were extensively cemented by low-Mg calcite spars, initially as rim cements and subsequently as concretions. Five petrographically distinct cement stages form a consistent paragenetic sequence across the Scapa Field. The dominant and pervasive second cement stage accounts for the majority of concretions, and is the focus of this study. Stable-isotope characterization of the cement is hampered by the presence of calcitic bioclasts and of later cements in sponge spicule moulds throughout the concretions. Nevertheless, trends from whole-rock data, augmented by cement separates from synlithification fractures, indicate an early calcite δ18O value of+0·5 to -1·5‰ PDB. As such, the calcite probably precipitated from marine pore fluids shortly after turbidite deposition. Carbon isotopes (δ13C=0 to -2‰ PDB) and petrographic data indicate that calcite formed as a consequence of bioclastic aragonite dissolution. Textural integrity of calcitic nannoplankton in the sandstones demonstrates that pore fluids remained at or above calcite saturation, as expected for a mineral-controlled transformation.
Electron probe microanalyses demonstrate that early calcite cement contains <2 mol% MgCO3, despite its marine parentage. Production of this cement is ascribed to a combination of an elevated aragonite saturation depth and a lowered marine Mg2+/Ca2+ ratio in early Cretaceous ‘calcite seas’, relative to modern oceans. Scapa cement compositions concur with published models in suggesting that Hauterivian ocean water had a Mg2+/Ca2+ ratio of ≤1. This is also supported by consideration of the spatial distribution of early calcite cement in terms of concretion growth kinetics. In contrast to the dominant early cement, late-stage ferroan, 18O-depleted calcites were sourced outwith the Scapa Member and precipitated after 1–2 km of burial.
Our results emphasize that bioclast dissolution and low-Mg calcite cementation in sandstone reservoirs should not automatically be regarded as evidence for uplift and meteoric diagenesis.
42 citations
TL;DR: It is noted that interest in KBS has been rekindled by the present interest in business process re-engineering, and progress in understanding and using development methodologies, validation methods and implementation are reviewed.
37 citations
TL;DR: In this paper, the Frank-Kamenetskii treatment was applied to a single pair of Arrhenius parameters in spite of significantly greater volatiles release in some experiments than in others.
22 citations
01 Feb 1996-International Journal of Human-computer Studies \/ International Journal of Man-machine Studies
TL;DR: A model for the relationship between the goal states achieved by a rule-based system, the set of inter-related rules that must fire to achieve each goal state, and the data items required for the rules in the rule sequence to fire is presented.
Abstract: Rule-based systems can be viewed as possessing two sets of properties: static and dynamic. Static properties are those that can be evaluated without executing the system, and dynamic properties can be evaluated only by examining how the system operates at run time. The dynamic properties of a rule-based system have been largely neglected in validation and verification work done thus far. Structural verification and static testing techniques do not yield information on how a rule-based system achieves its goals at run-time, given a set of input data. This paper presents a model for the relationship between the goal states achieved by a rule-based system, the set of inter-related rules that must fire to achieve each goal state, and the data items required for the rules in the rule sequence to fire. Then, we describe a method for applying this model to study the dynamic properties of a rule-based system. It is demonstrated that this model permits the validation of dynamic properties of a rule-based system, enabling system developers to decide: (1) if the manner in which the system pursues goals is valid according to the specifications (and expectations) of the designers; (2) what relationship exists between the quality of system output for a given test case and the goals achieved during problem-solving on that test case; and (3) how the overall problem-solving activity of the system relates to the availability of input data.
20 citations
TL;DR: The distribution of the ichnofauna is partly controlled by the lithologies in which they are preserved as mentioned in this paper, and the distribution of these organisms is also partitioned between different subenvironments of the mid-fan to produce a series of palaeoichnocoenoses.
Abstract: Sediments of Lower Carboniferous age in eastern Menorca, Balearic Islands contain a diverse and exceptionally well preserved ichnofauna, including Neonereites biserialis, Nereites isp., Arthrophycus isp., Dictyodora liebeana, two ichnospecies of Chondrites, several ichnospecies of Lophoctenium, two ichnospecies of Phycosiphon, Syncoprulus pharmaceus, annulated burrows and a vertical burrow.
The host lithologies are conglomerates, sandstones, siltstones and mudstones; most are the product of debris flows, and of high concentration [Ta(bc) intervals] to relatively dilute (Tcd/Tde intervals) turbidity currents. The rocks are interpreted as deposits of an inner- to mid-fan palaeoenvironment. Channelized deposits, sequences of overbank deposition and interchannel deposits interspersed with the deposits of unconfined debris flows and high concentration turbidity currents are present. The ichnofauna is most frequently, and best, preserved within the Td interval of turbidities, which are interpreted as interchannel deposits, produced by low concentration turbidity flows.
The distribution of the ichnofauna is partly controlled by the lithologies in which they are preserved. The rarity and poor preservation of trace fossils in the coarser grained facies contrasts with the detailed preservation of very delicate traces in the finer grained lithologies. However, the ichnofauna is also partitioned between different subenvironments of the mid-fan to produce a series of palaeoichnocoenoses. Thin intervals of interchannel deposits, separated by deposits of high concentration turbidity currents, repeatedly contain only Phycosiphon incertum and small (?juvenile)Dictyodora liebeana. These traces are interpreted as the products of opportunistic colonization of near-channel environments during episodes of quiescent deposition. Thicker intervals of interchannel deposits contain diverse assemblages of trace fossils characteristic of more stable environments, in which widespread colonization occurred. Overbank deposits at Cabo de Favaritz are medium- to thick-bedded, fine-grained beds. In these, the ichnofauna occurs in a simple, two-tier profile. The upper tier is dominated by Nereites isp.; this is underlain by a partially bioturbated layer characterized by large Dictyodora liebeana and Arthrophycus isp.
19 citations
TL;DR: The early Christians, and especially Paul, taught that salvation was to be received solely as a result of the gracious action of God himself and consequently by faith alone; such faith was in no sense some kind of human achievement but rather a dependence upon God himself as discussed by the authors.
Abstract: Until 1977 it was commonly believed that when New Testament writers affirmed that justification or salvation was not by works but by faith, they were opposing a view that was assumed to be held by first-century Jews, namely that admission to the saved community could be achieved on the basis of conditions which included performing good deeds or fulfilling the duties required by the Jewish law; the effect of these was to acquire merit on account of which God would accept the person and not take their sins into account. Over against this view the early Christians, and especially Paul, taught that salvation was to be received solely as a result of the gracious action of God himself and consequently by faith alone; such faith was in no sense some kind of human achievement but rather a dependence upon God himself.
12 citations
TL;DR: In this paper, it is argued that the self-heating of a bituminous coal will, at the temperatures concerned, be free from these effects and will therefore display genuinely steady behaviour.
Abstract: So-called steady state behaviour in laboratory scale self-heating of solid substrates such as carbons and cellulosics has rarely if ever been truly steady, but has displayed a maximum in the temperature history. This is due to volatiles and/or to porosity. In this paper it is argued that the self-heating of a bituminous coal will, at the temperatures concerned, be free from these effects and will therefore display genuinely steady behaviour. This assertion is tested by experimental work on a Scottish bituminous coal, in which sustained steady behaviour is indeed observed, with a heat release rate calculated to be approximate to 3 kW m(-3).
TL;DR: In this paper, ignition data for raw cotton is used in order to make predictions of hazards from hot particle entry into a previously thermally quiescent cotton bale. But the calculations make use of a numerical approach to ignition by a heat source.
Abstract: Previously presented ignition data for raw cotton are used in order to make predictions of hazards from hot particle entry into a previously thermally quiescent cotton bale. The calculations make use of a numerical approach to ignition by a heat source.
TL;DR: The Forum is intended to provide for dialogue and discussion among fire experts, scientists and consultants as discussed by the authors. Contributions to The Forum will not be refereed in the conventional sense, but will be subject to review by the Journal's Editorial Board relative to appropriateness, clarity, timeliness, and scope of interest.
Abstract: The Forum is intended to provide for dialogue and discussion among fire experts, scientists and consultants. Contributions to The Forum will not be refereed in the conventional sense, but will be subject to review by the Journal's Editorial Board relative to appropriateness, clarity, timeliness, and scope of interest. The Editorial Board will be the sole judge of those contributions to be published. Opinions expressed, however, are those of the authors and not of the Editors or Technomic Publishing Com pany, Incorporated.
TL;DR: In this paper, the principles underlying current tests for the spontaneous heating propensity of carbonaceous materials are examined and extended to enable rate expressions for such materials to be deduced, and the extensions are ex perimentally implemented for a Scottish bituminous coal.
Abstract: Principles underlying current tests for the spontaneous heating propensity of carbonaceous materials are examined and extended to enable rate expressions for such materials to be deduced. The extensions are ex perimentally implemented for a Scottish bituminous coal.
TL;DR: The distribution of sulphur between pyrite, kerogen, elemental sulphur, and the aromatic fraction of mudrock bitumens has been quantitated in two cored sections of immature marine Kimmeridgian strata which have experienced different levels of thermal stress as mentioned in this paper.
TL;DR: In this article, a detailed parametric study was conducted to evaluate the performance of a newly proposed hybrid solar housing development in Monymusk, Scotland, and the authors concluded that with careful construction, good thermal insulation, moderate thermal mass and properly controlled ventilation, the collector system can meet the space and domestic hot water heating requirements almost entirely.
TL;DR: In this paper, it was shown that the Frank-Kamenetskii (F-K) model of thermal ignition was not applicable, since the thermal behaviour was different from that expected when the model holds.
Abstract: A RECENT PAPER [1] presented temperature trajectories for the selfheating of a bituminous coal, and these were shown to have a dip when the temperature at the centre of the sample was around 380 ° C. It was clear from this and other features of the temperature histories for this material that the Frank-Kamenetskii (F-K) model of thermal ignition was not applicable, since the thermal behaviour was different from that expected when the model holds. All of this is fully discussed in the earlier paper. However, even for substrates for which the F-K model has been considered appropriate there is an inconsistency, never satisfactorily explained, whereby in a subcritical result the temperature of the sample always returns to the ambient (oven) temperature after a period of self heating. This has been reported by all investigators using oven heating and the F-K model, e.g., Bowes [2], reporting such work on sawdust. Referring to the eventual temperature drop displayed by a subcritical ex-
TL;DR: In this paper, the swelling by pyridine/benzene mixtures of low-rank coal briquette fragments was investigated, and the results were very close to those previously reported for PDE mixtures acting on a run-of-mine coal from the same source.
Abstract: The swelling by pyridine/benzene mixtures of low-rank coal briquette fragments is investigated, and the results are very close to those previously reported for pyridine/benzene mixtures acting on a run-of-mine coal from the same source. This is in spite of major differences in porosity between the two coals. The conclusion is that pore entry by the solvent plays no part in the swelling process.
TL;DR: In this paper, the authors established the basic theoretical framework for a system in which a stirred liquid explosive, conforming to the requirements and principles of the Semenov thermal explosion theory, was supported in such a way that half of its surface area experienced ambient temperature To and the other half ambient temperature T, where To > T. The model was applied to the liquid explosive DINA and, in a follow-up paper, times to explosion were determined numerically for marginally supercritical conditions.
Abstract: THE FIRST PAPER in this series [1] established the basic theoretical framework for a system in which a stirred liquid explosive, conforming to the requirements and principles of the Semenov thermal explosion theory [2], was supported in such a way that half of its surface area experienced ambient temperature To and the other half ambient temperature T., where To > T.. The model was applied to the liquid explosive DINA and, in a follow-up paper, times to explosion were determined numerically for marginally supercritical conditions. Being composed of a liquid compound the charge of explosive will have, unlike a gaseous substrate, a significant thermal mass, and truly rigorous consideration of times to explosion requires that the initial condition: