Electrostatic sensors applied to the measurement of electric charge transfer in gas-solids pipelines

This paper describes the development of a number of electric charge sensors. The sensors have been developed specifically to investigate triboelectric charge transfer which takes place between particles and the pipeline wall, when powdered materials are conveyed through a pipeline using air. A number of industrial applications exist for such gas-solids pipelines, including pneumatic conveyors, vacuum cleaners and dust extraction systems. The build-up of electric charge on pipelines and powdered materials can lead to electrostatic discharge and so is of interest from a safety viewpoint. The charging of powders can also adversely affect their mechanical handling characteristics and so is of interest to handling equipment engineers. The paper presents the design of the sensors, the design of the electric charge test rig and electric charge measurement test results

Application of nonlinear dynamics analysis to gas-solid flow system in horizontal pneumatic conveying of plastic pellets

Chaotic invariant and recurrence quantification analysis measures have characterised fully developed gas-solid flow in horizontal pneumatic conveying of plastic pellets. These measures describe the complexity in phase spaces (attractors) and recurrence plots, reconstructed from pressure and bottom arc-shaped electrostatic signals to characterise the behaviour of flow patterns. Different flow patterns were identified using high-speed video imaging of a transparent pipeline and classified at several operating conditions in a flow pattern map and state diagram. Recurrence plots were analysed for the identified flow patterns, which showed different qualitative structures. The chaotic invariant and recurrence quantification analysis measures were correlated with the state diagram, indicating that the fluctuations of pressure senor and electrostatic sensor signals can classify the flow patterns at different operating conditions. Combining the analysis measures for electrostatic signals can indicate whether the flow condition is above, near or below the minimum energy consumption operating conditions

The end of the world, or just 'goodbye to all that'? Contextualising the red deer heap from Links of Noltland, Westray, within late 3rd-millennium cal BC Orkney

As part of a major international research project, The Times of Their Lives, a programme of radiocarbon dating and Bayesian modelling was undertaken to refine the chronology of activities in one small but important part of the extensive Late Neolithic and Bronze Age settlement on Links of Noltland on the island of Westray, Orkney. The selected area (Trench D) is well known for having produced, next to a wall, the remains of a heap of at least 15 red deer carcasses, on top of which had been placed a large cod, a gannet’s wing along with part of a greater black-backed gull, and a pair of large antlers. This remarkable deposit had been preceded by, and was followed by, periods of cultivation and the deposition of domestic refuse. Refined date estimates have been produced, based on 18 radiocarbon determinations obtained from 16 samples from Trench D (including nine newly obtained dates, three from individual deer in the heap). These clarify when, during this long sequence of activities, the deer were heaped up: probably in the 22nd century cal bc, around the same time as Beaker pottery was deposited elsewhere on the Links. This allows comparison between the dated activities in this part of the site with activity elsewhere on the Links and also with other episodes of deer deposition in 3rd-millennium cal bc Orkney. It encourages exploration of the possible reasons for what appears to be a remarkable act of structured deposition. The significance of an earlier, much larger scale deposit featuring cattle remains at Ness of Brodgar is discussed in exploring the nature of Orcadian society and practices during the second half of the 3rd millennium cal bc

Auditory ossicles: a potential biomarker for maternal and infant health in utero

YesBackground: Carbon (δ13C) and nitrogen (δ15N) isotope ratios of collagen from teeth and bone are used to study human nutrition and health. As bones are constantly remodelling throughout life, isotopic values of bone collagen represent an average of several years. In contrast, human teeth do not remodel and their primary dentine contains only the isotopic data from the time of formation. In contrast to all other bones, human auditory ossicles also appear not to remodel. As they develop in utero and finish formation in the first 2 years of life, their collagen should also represent isotopic values of these two relatively short periods. Aim: By comparing δ13C and δ15N data from ossicles and incremental dentine, this study aims to investigate how two developmental periods of the ossicles, in utero and the first 2 years of life, reflect in collagen obtained from the ossicles. Subject and methods: Ossicle and tooth samples of 12 individuals aged 0.5 ± 0.4 years to 13 ± 1 years from the nineteenth century St. Peter’s burial ground in Blackburn were collected and processed to obtain bulk bone and incremental dentine collagen which was measured for δ13C and δ15N. Results: Averaged δ13C and δ15N of ossicles are lower when compared to every age group except after 3 years of age. Average offset between ossicles and dentine of different groups ranges from 0.4–0.9‰ for δ13C and from 0.3–0.9‰ for δ15N, with highest counterbalance at birth and after the first 5 months after birth. Conclusions: There appears to be a systematic offset between the dentine and ossicle data. It seems that the second phase of development does not influence the isotopic values of collagen significantly and the data we are obtaining from ossicles represents the in utero period.Research grant from The Society for the Study of Human Biology

Inventing the Neolithic? Putting evidence-based interpretation back into the study of faunal remains from causewayed enclosures.

ArticleThis is an Accepted Manuscript of an article published by Taylor & Francis in World Archaeology on 2015, available online: http://wwww.tandfonline.com/10.1080/00438243.2015.1072476The paper argues that our current understanding of the animal bones from causewayed enclosure sites in Britain is flawed. During the 1980-90s, a number of key interpretations, still frequently espoused, were based more upon anecdote and theory-driven assertion than on empirical evidence. An example is that evidence of bone processing (butchery and bone fracture) does not feature heavily in the faunal record from causewayed enclosures. Using data from the sites of Etton and Staines, this view must now be questioned. Both butchery and peri-mortem bone fracture are present in these assemblages in substantial quantities. These sites are compared with Ludwinowo 7, a Linearbandkeramik settlement site in Poland and there are considerable similarities between the three different sites. This suggests possibility that the broader economic utility of animal bone assemblages at causewayed enclosures has been underestimated, having been, up to now, regarded as ‘not indicative of domestic settlement’

Vertebrate resource exploitation, ecology, and taphonomy in Neolithic Britain, with special reference to the sites of links of Noltland, Etton, and Maiden Castle

SIGLEAvailable from British Library Document Supply Centre-DSC:DX202329 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Comparison of the electric charging properties of particulate materials in gas–solids flows in pipelines

The charging trends of particulate materials in gas–solid flows in pipelines are of considerable interest to designers of such flowsystems, particularly with regard to flow instruments based on electrostatic measurement principles. Such data may also be useful to other researchers in associated fields. The authors of this paper, therefore, set about obtaining such data empirically. In order to achieve this, a small-scale test rig was designed incorporating a 26.5mm bore pipeline, particulate material feeder, and electric charge measurement equipment. Charging trends are reported for flowvelocities in the range 16–36 m/s and particle concentrations in the range 5–50 mg/m3. Aluminium hydroxide, aluminium oxide, sugar and pulverised coal samples graded to have particle sizes in the range 90–106 mm were tested. Samples of aluminium hydroxide graded to between 45–53 and 63–75 mm were also teste