bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic COI‐tracking concept for the control of generators in multi‐machine power systems
Authors: Lan Zhou , Gan Deqiang , Shi Libao , Ni Yixin , Bi Tianshu 
Published: February 2007

AbstractIn the conventional excitation control concept, the power angle and frequency of a generator are driven to a pre‐designed operation point after the fault occurs. It is named as Constant Point Stabilization (CPS) concept in this paper. A novel concept, called dynamic Center of Inertia (COI)‐tracking concept is proposed in this paper. In the concept, the power angle and frequency of each generator track the dynamic COI of the power system. Compared to CPS concept, a salient feature the suggested dynamic COI‐tracking concept has is that the generators are not restricted to constant angle point or frequency any longer but track the dynamic COI trajectory of the system to keep synchronous in rotor angle and frequency. Wide area measurement system (WAMS) will be used to transform COI signals to each generator. The time delay within a certain limit of WAMS signals is permitted. To make comparison between the two concepts, the control system models based on the two concepts are first established. Then, using the back‐stepping method, two robust controllers are designed to achieve the control objectives of the two concepts. At last, dynamic simulations are carried out based on a 2‐area‐4‐machine test power system, and the control effects of the two controllers, together with that of the conventional AVR + PSS excitation system, are compared. Copyright © 2007 John Wiley & Sons, Ltd.
Evidence for association between multiple complement pathway genes and AMD
Authors: Dinu Valentin , Miller Perry L. , Zhao Hongyu 
Published: February 2007

AbstractIn this paper we explore the use of biological knowledge to supplement statistical analysis in identifying genes associated with disease. It has been previously found that the 402H variant in complement factor H (CFH) is associated with risk for developing age related macular degeneration (AMD). By focusing on the single nucleotide polymorphisms (SNPs) in the complement pathway, we were able to use the genotype data from a recently published AMD genome wide association study to identify two additional genes, C7 and MBL2, as potentially associated with subtypes of AMD. Two SNPs situated in introns of C7 and MBL2 could help differentiate between two forms of AMD: wet (more severe form of AMD) and dry (milder form of AMD). We identified a C7 haplotype associated with protection against developing wet AMD among individuals with homozygous CFH risk allele 402H (p‐value 0.001 for wet AMD versus dry AMD, odds ratio (OR) 0.16, OR 95% CI 0.05–0.49) as well as among individuals with at least one CFH risk allele (p‐value 0.007 for wet AMD versus dry AMD, OR 0.35, OR 95% CI 0.16–0.77). The fact that the statistical scores for the C7 and MBL2 SNPs were significant (low false discovery rate) at the pathway level, but not significant at the genome level suggests that focusing at the pathway level can be beneficial for identifying SNP signals that would be lost at the genome‐wide level. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
A boring in the millstone grit near darwen, lancashire
Authors: Lacey William S. 
Published: February 2007

AbstractThe geological section exposed in a deep boring for water in the Millstone Grit near Darwen, Lancashire, is described. Details are given of the lithology and palaeontology throughout a thickness of 700 ft. of rock, extending from the Holcombe Brook Grit well into the Fletcher Bank Grit. In discussion, the rhythmic character of sedimentation is emphasised, and attention is also particularly drawn to the importance of marine bands (with Gastrioceras aff. sigma, Reticuloceras reticulatum early mut. γ and late mut. β) and a Lingula band in determining the Grits.
The natural moisture‐content, voids (porosity) and compaction of unconsolidated clayey rocks
Authors: Boswell P. G. H. 
Published: February 2007

AbstractData relating to the natural moisture‐content of samples of saturated fine‐grained sediments, ranging from Devonian to Recent, are assembled and discussed. They indicate that the voids occupy volumes proportionally much greater than those shown by published figures for porosity obtained by standard displacement methods. Void‐ratio/pressure (depth) relationships and formulae devised to facilitate prediction are thus likely to need revision.The natural moisture‐content varies with the predominance of particular clay‐minerals, as well as with grading. The special cases of calcareous muds, organic muds, varves and boulder clays (tills), are discussed, together with geological implications of the further study of moisture‐contents.
Some aspects of the new red desert in britain
Authors: Shotton F. W. 
Published: February 2007

AbstractA number of points of interest and controversy in British Permo‐Trias stratigraphy are discussed. Evidence is put forward to suggest that the location of the British area in relation to the poles was very different from that of the present day. The origin of the red colouration in the dune sands is discussed. An attempt is made to reconstruct the outcrop geology of northern England in New Red times, and from this deductions are drawn about the extent of the Zechstein sea. The nature of the false‐bedding in the dune sands is analysed and conclusions are drawn about the extent of the sand sea and the regional pattern of prevailing winds. The relation between false‐bedding and true dip is discussed in an appendix.
Some sedimentary structures from the lower Keuper Sandstones
Authors: Cummins W. A. 
Published: February 2007

AbstractSome sedimentary structures from the Lower Keuper Sandstones, recorded by H. C. Beasley mainly from the area round Liverpool, are redescribed. Two of these, flute casts and groove casts, are well‐known in the marine greywacke facies. Attention is drawn to records of their occurrence in other facies. The origin of these structures is briefly discussed.
The black marble of Ashford‐in‐the‐water, Derbyshire
Authors: Ford Trevor D. 
Published: February 2007

AbstractThe paper records the little‐known and now extinct marble industry of Ashford‐in‐the‐Water, Derbyshire. An account of the distribution of the dark‐grey limestone used as Black Marble, and the other limestones and materials used for inlaying is included. Methods of mining and processing the Marble and the history of the industry are described.
On a fossil tree found in an opencast coal site near Wigan, Lancashire
Authors: Broadhurst F. M. , Magraw D. 
Published: February 2007

AbstractThe cast of a Coal Measures tree seen in position of growth is described. The cast is about 13 feet long, and evidence is given that the original tree trunk was probably at least 38 feet long before it became completely buried in sediment. The precise history of the tree is unknown but the rate of sedimentation round about it must have been very high.
Geophysical investigations in the Vale of Clwyd
Authors: Wilson C. D. V. 
Published: February 2007

AbstractA seismic refraction survey has shown three layers below the drift, correlated with Trias, Upper Carboniferous and Carboniferous Limestone, respectively. The thicknesses of the first two have been estimated. A detailed gravity survey has been co‐ordinated with three of the four seismic lines. One of the faults on the west of the Vale has been traced by the gravity survey for 11/2 miles and identified on a seismic line. It is shown to be either a single fault of 700 feet throw and approximately 45° hade, or else two or more step‐faults. The first arrival times at this line can all be explained on the simple ray theory with the assumption of wave diffraction. The significance of the later arrivals is discussed.The Vale is shown to be divided into basins of Trias by the faults on the west side, but the Vale of Clwyd fault on the east side is continuous.
Some recent advances in the study of deltaic sedimentation
Authors: Van Straaten L. M. J. U. 
Published: February 2007

AbstractRecent advances in delta sedimentology are briefly summarized. Most of the review is based on data that have been published elsewhere. Some new information is presented concerning the Rhǒne delta, e.g., the distribution of its marine environments (Fig. 2) and the regional variations in differentiation of the mollusc shell assemblages (Fig. 3). The bulk of the sediments in deltas of the Rhǒne type are formed in marine environments. The volumetric proportions between deposits of different facies, as found in many recent deltas, may be very dissimilar to those in fossil (pre‐Quaternary) deltas, formed under “non‐glacial” conditions (cf. Fig. 7).
Recent advances in the palæontology of fishes
Authors: Westoll T. S. 
Published: February 2007

AbstractRecent advances in our knowledge of the lower vertebrates are extremely striking, and result from more widespread and active geological exploration, from greatly improved possibilities of collecting, from very great advances in methods of clearing the rock from the fossils, and from increasingly deep studies on comparative anatomy and histology. Earlier classifications have had to be revised, and in some respects more may be known of details of anatomy of fossil fishes than can be found in the literature on recent forms. This review of progress is also a pointer to further desirable work.
A pebble bed in the Carboniferous limestone at Llysfaen, N. Wales
Authors: Simpson Brian 
Published: February 2007

AbstractThe pebble bed described is located in the Carboniferous Limestone at Llysfaen and, on the basis of the foraminifera, a middle S2 age is suggested for it. The lithological character of the bed is described, a probable source for the pebbles is suggested and a shallow water environment is postulated for its locus of accumulation.
The origin of the Mersey anD Dee Estuaries
Authors: Gresswell R. Kay 
Published: February 2007

AbstractThe present coastal configurations of these estuaries are contrasted with known fluvial drowned estuaries and attention is drawn to their non‐fluvial characteristics. Two other sub‐parallel depressions in Wirral and southwest Lancashire are described, together with the sub‐glacial surfaces of all four. Their floors are found to contain irregular rock‐bound hollows, and other features reminiscent of glaciated areas. It is suggested that they are escape routes taken by Irish Sea ice hemmed in by the mountains of Wales and the outliers of the Pennines. The term “iceways” is suggested for such ice‐gouged features. A rock shelf in the University area of Liverpool is also tentatively attributed to the same ice erosion.
Kimberlites of Northeastern USSR and allied problems
Authors: Lebedev A. P. 
Published: February 2007

AbstractKimberlites are discussed in the light of knowledge obtained from their occurrence in the Siberian platform. Their relation to tectonic pattern, the basement and its cover are considered together with their petrographic and chemical composition and their association with basaltic rocks. It is concluded that kimberlites originated from a deep‐seated kimberlite magma which was injected periodically. The chemical resemblance to peridotes is noted and the peculiarities of kimberlite are put down to periodic enrichment of peridotitic magma with volatiles. It is suggested that diamonds owe their origin to both primary and assimilated carbon.
The carboniferous limestone of the blore‐with‐Swinscoe district, Northeast Staffordshire, with revisions to the stratigraphy of neighbouring areas
Authors: Parkinson D. , Ludford A. 
Published: February 2007

AbstractThis investigation of previously undescribed country along the Staffordshire‐Derbyshire border indicated the need for re‐examination of adjoining areas described in 1950 and 1951. The main revisions concern the ages of certain beds and the nature of the unconformities. Evidence is adduced of vertical earth‐movements in pre‐S2 and in middle D1 time.
Fining‐upwards cycles in alluvial successions
Authors: Allen J. R. L. 
Published: February 2007

AbstractFining‐upwards cycles on a scale of thickness from a few metres to a few tens of metres, and consisting of a coarse grade member (erosive base) overlain by a fine grade member, are the hall‐mark of a distinct non‐marine sedimentary facies widely distributed in space and time. Using data on modern alluvial sediments, it is shown that the interpretation of the cycles in terms of an alluvial environment is probably correct. The cyclicity itself cannot yet be accounted for, although three principal factors are likely to have been involved.
Intrusive quartz latites in the Blaenau Ffestiniog area, Merioneth
Authors: Bromley Alan V. 
Published: February 2007

AbstractCertain flow‐banded and fragmental rocks amongst the Moelwyn Volcanic Series are shown to be of intrusive origin, although at one time they were believed to be extrusive lavas, ashes and agglomerates. Thus the thickness and extent of the volcanic rocks are greatly reduced. New palaeontological evidence shows that part of the Moelwyn Volcanic Series is Caradocian.
Reversed coiling trend in Gryphaea arcuata
Authors: Burnaby T. P. 
Published: February 2007

AbstractThe law of growth of the left valve in Gryphaea arcuata is investigated, and it is shown that it is possible to define a growth‐invariant measure of tightness of coiling.Recent papers by A. Hallam and G. M. Philip are discussed. The latter author's conclusions are shown to be based upon premises which are untenable. It is here concluded that there is a change in tightness of coiling from the angulata to the gmuendense‐bucklandi horizons at the Glamorgan, Yorkshire, and S. England localities from which Hallam collected his samples of Gryphaea shells. The trend is towards less tightly coiled shells in the higher beds, amounting to an average reduction of a few millimetres in peripheral length at an arbitrary constant radius of 20 mm. There are differences between localities of the same order of magnitude, and it is therefore proper to adopt a cautious attitude towards this result. It is however clear that the pronounced apparent increase in shell coiling originally reported by Trueman in 1922 is simply the direct concomitant of increased size.
The stratigraphy and origin of the portaskaig boulder bed series (Dalradian)
Authors: Kilburn C. , Shackleton R. M. , Pitcher W. S. 
Published: February 2007

AbstractThe late Pre‐Cambrian Portaskaig Boulder Bed Series shows a very uniform sequence for some 600 km along the Caledonian strike, from Connemara on the west coast of Ireland to Aberdeenshire in Scotland. The Series, which is divided into four groups of beds, comprises numerous individual boulder beds separated by stratified sediments. The lower boulder beds are carbonate‐bearing and contain abundant intrabasinal fragments of dolomite and few extrabasinal crystalline rocks while the higher beds are psammitic and contain mainly extrabasinal crystalline rocks. Varve‐like banding, involutions and sandstone polygons suggest periglacial conditions. It is concluded that the boulder beds represent subaqueous tills deposited on unconsolidated sediments. Contemporaneous deformation of some of these sediments is attributed to the movement of ice, although the possibility that sliding of the unconsolidated sediments occurred locally is considered.
The deformation of quartz in a granite
Authors: Phillips W. J. 
Published: February 2007

AbstractThe deformation structures in a quartz porphyroclast are described in detail and the sequence of their formation is established. During the final stages of plastic deformation, the crystal structure was distorted by undulatory bending resulting in undulose extinction, and by the development of oblique surfaces of optical discontinuity lying parallel to the axix of undulatory bending and about 40° to the optic axis. The optic axis of the crystal has been rotated into parallelism with the oblique surfaces of optical discontinuity along a recrystallised zone, and the axis of rotation approximately coincides with the axis of undulatory bending. It is postulated that the reorientation of the crystal structure was accomplished by the intragranular rotation within needle‐like units elongated parallel to the axis of undulatory bending, and that this was initiated by movements along the oblique surfaces of discontinuity in response to external stresses. Similar structures with signs of reorientation of the optic axis have been observed in many pophryroclasts with very different orientations and it is suggested that the postulated mechanism of reorientation might also explain the commonly observed (ac) girdle in the quartz orientation patterns of polycrystalline tectonites.Subsequent recrystallisation in place and later primary recrystallisation from nuclei released local strain in the most distorted parts of the porphyroclast and resulted in the formation of numerous minor grains. The minor grains formed by primary recrystallisation have a pronounced preferred orientation which is unrelated to the orientation of the parent crystals and it appears that this developed without any appreciable movement of the fabric.
Spatial and seasonal pebble beach profile characteristics
Authors: Caldwell N. E. , Williams A. T. 
Published: February 2007

AbstractBeach profiles along eight sections of two fringing pebble beaches located in the Glamorgan Heritage Coast, Wales were regularly surveyed for over one year. The data were used to examine spatial and seasonal beach profile variations by utilizing them in several graphical procedures. Results showed seasonal variations in terms of beach profile configuration, beach face slope and the rate of profile change, although these variations were not necessarily concurrent. This highlights the special case of fringing pebble beaches on which accretional profiles are probably compensated for by erosional profiles alongshore at any one time. This makes it difficult to generalize spatially the profile response of an entire beach system. For this reason, the rate of profile change may more realistically reflect periodic variations in wave regime, which in European latitudes can be approximated with the summer and winter seasons.
Pyrite formation and the drowning of a palaeosol
Authors: Wright V. Paul 
Published: February 2007

AbstractPalaeosols may be modified in a variety of ways during burial diagenesis but significant alteration can take place during the earliest phases of burial caused by rising groundwaters. A calcrete palaeosol, the Heatherslade Geosol, from the Lower Carboniferous of South Wales, contains abundant pyrite which overprinted the original soil fabrics. The pyrite is interpreted as the product of anaerobic conditions caused by drowning during the early stages of a marine transgression. Unusual diamond‐shaped forms of pyrite occur which possibly represent pseudomorphs after gypsum.
Comparative Tertiary petroleum geology of the Gulf Coast, Niger, and Beaufort‐Mackenzie delta areas
Authors: Curtis Doris M. 
Published: February 2007

AbstractOil and gas are produced from Tertiary sandstone reservoirs in deltaic and related depositional systems in the Gulf Coast (U.S.), Niger (Africa), and Beaufort‐Mackenzie (Canada‐Alaska) basins. In each area there is an orderly, predictable interrelationship of sedimentation, stratigraphy, depositional environment, and structure, with the characteristics, ages, and distribution of producing trends.In comparing and contrasting the three areas, it is apparent that they have many essential aspects in common, resulting from the fact that they are relatively young, subsiding paralic basins on 'Atlantic type' or passive margins. They contain thick accumulations of deltaic terrigenous sediments that have prograded in regressive basin‐filling sequences as the basins subsided. Therefore each has a vertical gross lithologic sequence with shale at the base, overlain by interbedded sandstones and shales, overlain by massive sandstones. The vertical sequence is repeated laterally from the basin landward. In each basin the stratigraphic units of the sequences thicken basinward across a series of normal, listric, down‐to‐the‐basin syndepositional faults, with which are associated 'rollover' anticlines which form traps. Trapping associated with diapiric structures is also characteristic of all three areas.Although similarities among these areas is striking, significant differences are related to their different geologic settings and geologic histories. For example, the presence of salt in the Gulf Coast basin has resulted in a wide variety of salt dome‐related trapping mechanisms in addition to the shale diapirs and roll‐over anticlines common to all three areas. Pre‐Tertiary tectonic settings, different in each case, control basin configurations and affect structural trends. Vertical and lateral differences in depositional systems and sequences, as well as variations in delta morphology and sandstone geometries, result from variations in ratios of rates of deposition to rates of subsidence.The framework for the occurrence of oil and gas is well understood in the maturely‐explored and intensively‐studied Gulf Coast Tertiary basin. Concepts developed there can be applied to developing the less‐explored Niger basin and to exploring the frontier Beaufort‐Mackenzie basin. An extensive bibliography is included.
Experiments in long‐range climate control
Authors: Donn William L. 
Published: February 2007

AbstractExtrapolation of the palaeoclimate chronology of the past million years or so seems to leave little doubt that another glacial stage can be expected in the near geologic future. On a shorter time scale it appears that the increasing greenhouse effect from the use of fossil fuel will raise atmospheric temperature by 2 to 3 °K within a hundred years. The possibility of man's reversing or at least weakening these portentous climate changes is investigated here with the use of a thermodynamic climate model. Preliminary results indicate that the climate effects referred to may be reversible if caught early and certainly suggest that further and more sophisticated attention be given the subject.
Dimlington Stadial (Late Devensian) ice‐wedge casts and involutions in the Severn Estuary, southwest Britain
Authors: Allen J. R. L. 
Published: February 2007

AbstractThe largely concealed sub‐Flandrian bedrock surface in the Severn Estuary, chiefly known from borings and chart soundings, has the form of a valley within a valley. In the aftermath of an unusual storm in March 1986, which removed from many places the obscuring modern sediments normally present, periglacial structures were recognized on the floor and upper margins of the upper valley at ten widely scattered localities. The structures occur only where the valley is formed on relatively soft Triassic and Jurassic mudrocks; they involve gravels and/or red‐brown sands belonging to the Main Terrace sequence, but in some places incorporate local gravels. There are no completely convincing indications of cold conditions where the relatively strong Silurian and Old Red Sandstone rocks and the Carboniferous Limestone form the valley floor. The altitudinal relationships of the involutions and wedges, together with the scale of the outer valley, suggest that this sub‐Flandrian rock bench was merely re‐excavated during the Late Devensian. Then permafrost developed while the river lay confined within the much narrower inner gorge.