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Number of results: 6
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Abstract

Reducing the effect of unwanted vibrations is an important topic in many engineering applications. In this paper we describe some recent developments in the area of passive vibration mitigation. This is based on a new device called the inerter which can be exploited in a range of different contexts. In this paper we consider two recent examples; (i) where a flywheel inerter is combined with a hysteretic damper, and (ii) in which a pivoted bar inerter is developed for a machining application. In both cases, experimental test results show that the devices can outperform existing methods.
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Authors and Affiliations

David J. Wagg
1
ORCID: ORCID

  1. Department of Mechanical Engineering, University of Sheffield, Sheffield, United Kingdom
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Abstract

The Oligocene (Rupelian) Byram Formation (Vicksburg Group) in Alabama, USA, is divided into three members, including (in ascending order) the Glendon Limestone, unnamed marl, and the Bucatunna Clay. The Oligocene marine units in Alabama have been historically under-investigated, but bulk samples recently obtained from Glendon Limestone Member exposures at site AWa-9 in Washington County yielded 20 unequivocal elasmobranch and teleost taxa. This surprisingly diverse paleofauna, based on isolated teeth, bones and otoliths, includes the new taxon, Gobiosoma? axsmithi sp. nov., as well as “Aetomylaeus” sp., Albula sp., Aplodinotus gemma Koken, 1888, Ariosoma nonsector Nolf and Stringer, 2003, Balistidae indet., Citharichthys sp., Myliobatoidei indet., Diretmus? sp., Hemipristis sp., Negaprion aff. N. gilmorei (Leriche, 1942), Pachyscyllium sp., Paralbula sp., Physogaleus sp., Preophidion meyeri (Koken, 1888), Sciaena pseudoradians (Dante and Frizzell in Frizzell and Dante, 1965), Sciaenops? sp., Sparus? elegantulus Koken, 1888, Sphyraena sp., and Syacium sp. Additional remains were recovered but could not be identified beyond undetermined Elasmobranchii or Teleostei. All these taxa represent first occurrences within the Glendon Limestone Member in Alabama, and the “Aetomylaeus” sp., Pachyscyllium sp., Paralbula sp., and Sciaenops? sp. specimens represent the first occurrences of each in the Oligocene of the Gulf Coastal Plain of the USA. We also report the first record of Oligocene Paralbula Blake, 1940 teeth, and the first occurrence of an Oligocene member of the Balistidae in the Western Hemisphere. This marine vertebrate assemblage indicates that the Glendon Limestone Member at site AWa-9 represented a subtropical to temperate, middle shelf paleoenvironment with a paleowater depth interpreted as 30–100 m.
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Authors and Affiliations

Jun A. Ebersole
1
David J. Cicimurri
2
Gary L. Stringer
3

  1. McWane Science Center, 200 19th Street North, Birmingham, AL 35203, USA
  2. South Carolina State Museum, 301 Gervais Street, Columbia, SC 29201, USA
  3. Museum of Natural History, 708 University Avenue, University of Louisiana at Monroe, Monroe, LA 71209, USA
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Abstract

The nature of the Cenomanian–Turonian Oceanic Anoxic Event (CTOAE) and its δ13 C Excursion is considered in the light of (1) the stratigraphical framework in which the CTOAE developed in the European shelf seas, (2) conclusions that can be drawn from new detailed investigations of the Chalk succession at three locations in England, at Melton Ross and Flixton in the Northern Province where organic-rich ‘black bands’ are present, and at Dover in the Southern Province (part of the Anglo-Paris Basin) where they are absent, and (3) how these conclusion fit in with the present understanding of the CTOAE. The application of the cerium anomaly method (German and Elderfield 1990) at Dover, Melton Ross and Flixton has allowed the varying palaeoredox conditions in the Chalk Sea and its sediments to be related to the acid insoluble residues, organic carbon, δ18O (calcite), δ13C (calcite), δ13C (organic matter), Fe 2+ and Mn2+ (calcite), and P/TiO2 (acid insoluble residue). This has provided evidence that the initial stages of the δ13C Excursion in England were related to (1) a drop of sea level estimated at between 45 and 85 metres, (2) influxes of terrestrial silicate and organic detritus from adjacent continental sources and the reworking of exposed marine sediments, and (3) the presence of three cold water phases (named the Wood, Jefferies and Black) associated with the appearance of the cold-water pulse fauna during the Plenus Cold Event. Conditions in the water column and in the chalk sediment were different in the two areas. In the Northern Province, cerium-enriched waters and anoxic conditions were widespread; the δ13C pattern reflects the interplay between the development of anoxia in the water column and the preservation of terrestrial and marine organic matter in the black bands; here the CTOAE was short-lived (~0.25 Ma) lasting only the length of the Upper Cenomanian Metoicoceras geslinianum Zone. In the Southern Province, water conditions were oxic and the δ13C Excursion lasted to the top of the Lower Turonian Watinoceras devonense Zone, much longer (~1.05 Ma) than in the Northern Province. These differences are discussed with respect to (1) the Cenomanian–Turonian Anoxic Event (CTAE) hypothesis when the ocean-continent-atmosphere systems were linked, (2) limitations of chemostratigraphic global correlation, and (3) the Cenomanian–Turonian Anoxic Event Recovery (CTOAER), a new term to define the varying lengths of time it took different oceans and seas to recover once the linked ocean-continent-atmosphere system was over. The possibility is considered that glacio- eustasy (the glacial control hypothesis of Jeans et al. 1991) with the waxing and waning of polar ice sheets, in association with the degassing of large igneous provinces, may have set the scene for the development of the Cenomanian–Turonian Anoxic Event (CTAE).
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Authors and Affiliations

Christophers V. Jeans
1
David S. Wray
2
C. Terry Williams
3
David J. Bland
4
Christopher J. Wood
5

  1. Department of Earth Sciences, University of Cambridge, Downing Place, Cambridge, CB2 3EN, UK
  2. School of Science, University of Greenwich, Pembroke, Chatham Maritime, Kent, ME4 4TB, UK
  3. Department of Mineralogy, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
  4. 15 Pains Close, Pinner, Middlesex, HA5 3BN, UK
  5. Deceased
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Abstract

Upper Cretaceous ammonites are described from six horizons in the mammal-bearing terrigenous-clastic sequences of western Uzbekistan, as follows: Upper Cenomanian, with Placenticeras sp. juv. cf. cumminsi Cragin, 1893 and Metoicoceras geslinianum (d’Orbigny, 1850); Lower Turonian with Tragodesmoceras cf. mauryae Kennedy and Wright, 1981, Placenticeras kharesmense (Lahusen, 1884), Watinoceras coloradoense (Henderson, 1908), Watinoceras amudariense (Arkhangelsky, 1916b), Metasigaloceras rusticum (J. Sowerby, 1823), Morrowites wingi (Morrow, 1935), Sciponoceras cf. bohemicum bohemicum (Fritsch, 1872), and Yezoites amudariensis (Arkhangelsky, 1916b); Middle Turonian with Collignoniceras woollgari woollgari (Mantell, 1822); Upper Turonian with Lewesiceras mantelli (Wright and Wright, 1951) and Placenticeras crassum Ilyin, 2020; a single Placenticeras semiornatum (d’Orbigny, 1850) from around the Coniacian/Santonian boundary, and Santonian Placenticeras polyopsis (Dujardin, 1837).
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Authors and Affiliations

David J. Ward
1 2
Chris King
Noel J. Morris
1 3
William James Kennedy
4

  1. Science Group, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
  2. Crofton Court, 81 Crofton Lane, Orpington, Kent BR5 1HB, UK
  3. e-mail: niccamore@gmail.com
  4. Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, UK, and Department of Earth Sciences, South Parks Road, Oxford OX1 3AN, UK
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Abstract

The article describes the problem of selection of heat treatment parameters to obtain the required mechanical properties in heat- treated

bronzes. A methodology for the construction of a classification model based on rough set theory is presented. A model of this type allows

the construction of inference rules also in the case when our knowledge of the existing phenomena is incomplete, and this is situation

commonly encountered when new materials enter the market. In the case of new test materials, such as the grade of bronze described in

this article, we still lack full knowledge and the choice of heat treatment parameters is based on a fragmentary knowledge resulting from

experimental studies. The measurement results can be useful in building of a model, this model, however, cannot be deterministic, but can

only approximate the stochastic nature of phenomena. The use of rough set theory allows for efficient inference also in areas that are not

yet fully explored.

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Authors and Affiliations

S. Kluska-Nawarecka
K. Regulski
D. Wilk-Kołodziejczyk
Z. Górny
Z. Jančíková
J. David

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