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In this paper we investigate the effect of an inhomogeneous and unsteady velocity field incident on an array of rigid circular cylinders arranged within a circular perimeter (diameter
) of varying solid fraction
, where the unsteady flow is generated by placing a cylinder (diameter
) upwind of the array. Unsteady two-dimensional viscous simulations at a moderate Reynolds number (
) and also, as a means of extrapolating to a flow with a very high Reynolds number, inviscid rapid distortion theory (RDT) calculations were carried out. These novel RDT calculations required the circulation around each cylinder to be zero which was enforced using an iterative method. The two main differences which were highlighted was that the RDT calculations indicated that the tangential velocity component is amplified, both, at the front and sides of the array. For the unsteady viscous simulations this result did not occur as the two-dimensional vortices (of similar size to the array) are deflected away from the boundary and do not penetrate into the boundary layer. Secondly, the amplification is greater for the RDT calculations as for the unsteady finite Reynolds number calculations. For the two highest solid fraction arrays, the mean flow field has two recirculation regions in the near wake of the array, with closed streamlines that penetrate into the array which will have important implications for scalar transport. The increased bleed through the array at the lower solid fraction results in this recirculation region being displaced further downstream. The effect of inviscid blocking and viscous drag on the upstream streamwise velocity and strain field is investigated as it directly influences the ability of the large coherent structures to penetrate into the array and the subsequent forces exerted on the cylinders in the array. The average total force on the array was found to increase monotonically with increasing solid fraction. For high solid fraction
, although the fluctuating forces on the individual cylinders is lower than for low
, these forces are more correlated due to the proximity of the cylinders. The result is that for mid to high solid fraction arrays the fluctuating force on the array is insensitive to
. For low
, where the interaction of the cylinders is weak, the force statistics on the individual cylinders can be accurately estimated from the local slip velocity that occurs if the cylinders were removed.
OBJECTIVES/SPECIFIC AIMS: The Indiana CTSI is investigating innovative approaches to integrate resources that will enrich scientific investigators. Our goals are to enhance the availability and communication among CTSI resources, for example internal funding, and to expand existing mentorship. METHODS/STUDY POPULATION: Developed a reviewer database that serves to streamline reviewer identification, decrease reviewer fatigue, and promote collaboration among disciplines. We started with a pool of NIH-funded investigators from across the Indiana CTSI core institutions and merged this list with previous CTSI reviewers and internal funding awardees. To expand this list, names and expertise from new faculty hires were added. RESULTS/ANTICIPATED RESULTS: Though this tool is relatively new, we have already observed an increase in junior faculty awareness and engagement with the CTSI. This database allows for increased opportunities of junior faculty to serve as reviewers and to refine grant writing skills and provides a platform for networking and collaborating across disciplines. It also allows for increased integration of programs with a shared reviewer database and promotes grant review standardization. DISCUSSION/SIGNIFICANCE OF IMPACT: Our database utilization seeks to decrease the time for junior faculty to obtain their first extramural grant, to enhance promotion and tenure packages, strengthen integration among CTSI programs, increase interactions between clinical and basic science investigators, and promote team science.
The scaling of turbulent motions is investigated by considering the flow in the eigenframe of the local strain-rate tensor. The flow patterns in this frame of reference are evaluated using existing direct numerical simulations of homogeneous isotropic turbulence over a Reynolds number range from
up to 1131, and also with reference to data for inhomogeneous, anisotropic wall turbulence. The average flow in the eigenframe reveals a shear layer structure containing tube-like vortices and a dissipation sheet, whose dimensions scale with the Kolmogorov length scale,
. The vorticity stretching motions scale with the Taylor length scale,
, while the flow outside the shear layer scales with the integral length scale,
. Furthermore, the spatial organization of the vortices and the dissipation sheet defines a characteristic small-scale structure. The overall size of this characteristic small-scale structure is
in all directions based on the coherence length of the vorticity. This is considerably larger than the typical size of individual vortices, and reflects the importance of spatial organization at the small scales. Comparing the overall size of the characteristic small-scale structure with the largest flow scales and the vorticity stretching motions on the scale of
shows that transitions in flow structure occur where
and 250. Below these respective transitional Reynolds numbers, the small-scale motions and the vorticity stretching motions are progressively less well developed. Scale interactions are examined by decomposing the average shear layer into a local flow, which is induced by the shear layer vorticity, and a non-local flow, which represents the environment of the characteristic small-scale structure. The non-local strain is
in width and height, which is consistent with observations in high Reynolds number flow of a
wide instantaneous shear layer with many
-scale vortical structures inside (Ishihara et al., Flow Turbul. Combust., vol. 91, 2013, pp. 895–929). In the average shear layer, vorticity aligns with the intermediate principal strain at small scales, while it aligns with the most stretching principal strain at larger scales, consistent with instantaneous turbulence. The length scale at which the alignment changes depends on the Reynolds number. When conditioning the flow in the eigenframe on extreme dissipation, the velocity is strongly affected over large distances. Moreover, the associated peak velocity remains Reynolds number dependent when normalized by the Kolmogorov velocity scale. It signifies that extreme dissipation is not simply a small-scale property, but is associated with large scales at the same time.
During past three years from 1982 to 1984 we saw the further progress in the planets and satellites research by the space and ground-based technique, in the analysis and interpretation of the observational data. Inspite of some decrease of the activity in the planetary spacecrafts launches during this period (except of two Soviet missions to Venus) many important scientific results were obtained from the continued reduction and analysis of the measurements which were performed by Mariner 10 (Mercury), Pioneer Venus, Venera 13 and 14, Viking (Mars), Pioneer 10 and 11, and Voyager 1 and 2.
During 1990 we surveyed the southern sky using a multi-beam receiver at frequencies of 4850 and 843 MHz. The half-power beamwidths were 4 and 25 arcmin respectively. The finished surveys cover the declination range between +10 and −90 degrees declination, essentially complete in right ascension, an area of 7.30 steradians. Preliminary analysis of the 4850 MHz data indicates that we will achieve a five sigma flux density limit of about 30 mJy. We estimate that we will find between 80 000 and 90 000 new sources above this limit. This is a revised version of the paper presented at the Regional Meeting by the first four authors; the surveys now have been completed.
NGC 4945 is with D ~3-4 Mpc one of the nearest starburst galaxies known and a goldmine for molecular cloud research. A multi-line mm-wave study has been carried out towards its nuclear region with the Swedish-ESO Sub-millimetre Telescope (SEST). The study covers the frequency range from 82 GHz to 354 GHz and includes 80 transitions of 19 molecules, including rare isotope-bearing species. Applying a Large Velocity Gradient (LVG) code to the data, H2 densities and column densities of 22 molecular species are calculated. Many of these species indicate the presence of a prominent high density interstellar gas component characterized by nH2 ~105cm-3. Abundances of molecular species are calculated and compared with abundances observed toward the starburst galaxies NGC 253 and M 82 and galactic sources. Apparent is an ‘overabundance’ of HNC and CN in the nuclear environment of NGC 4945. NGC 4945 is the second known starburst galaxy with an HNC/HCN abundance ratio ≥1. Carbon, nitrogen, oxygen and sulfur isotope ratios are also determined. The data indicate that high 18O/17O, low 16O/18O and 14N/15N and perhaps also low 32S/34S ratios (6.4±0.3, 195±45, 105±25 and 13.5±2.5, respectively) are characteristic properties of a starburst environment in an advanced evolutionary stage.
This paper describes an integrated series of sedimentological and palynological studies of the arenaceous deposits which infill the large alluvial basin of Grerat D'nar Salem, which is located on a limestone plateau in the semi-arid pre-desert of Tripolitania north-west of the town of Beni Ulid. This research shows that in the early and middle Holocene this depression was occupied by a large semi-permanent or permanent water body which was surrounded by a grass-steppe vegetation with some tree and shrub species, perhaps growing in wetter stream- and wadi-beds. Sometime in the mid-Holocene the region became much more arid, the lake disappeared, matching the pattern of environmental change observed elsewhere in northern Africa. The geomor-phic environment became dominated by aeolian processes, interrupted by occasional winter floods, in a landscape dominated by grass steppe — essentially the situation that has continued to the present day. It is clear from general biogeographical and geomorphic considerations that Romano-Libyan floodwater farming in the region must have brought about significant changes in the character of wadi floors. Field survey indicates that it has also left a legacy in the contemporary distribution of plants, animals and runoff in the modern landscape. Nevertheless, no clear evidence has emerged from this study that the widespread and intensive flood-water farming, evidenced by the archaeological remains in the area, was associated with either a climate or a landscape notably different from that of today. The new palynological evidence suggests that the nature of the related ancient cultivation at Grerat is better viewed as a monoculture, rather than the mixed farming deduced previously for wadi-floor areas. There is no evidence that any naturally-occurring environmental change was associated with the introduction or loss of floodwater farming in the region. There is some sedimentological evidence that such activity might have led to problems of soil salinity in this basin.
This article describes the interdisciplinary methods developed by the UNESCO Libyan Valleys Survey in connection with the study of ancient agriculture. These methods combine the techniques of settlement archaeology with those of the earth sciences and palaeoeconomics. The interactive nature of the enquiry does not resolve all the questions, but it can help to re-shape those questions and suggest new lines of enquiry. The example of the Wadi Mansur is used here to demonstrate the application of both conventional and new techniques and the contribution this can make to our appreciation of ancient land use in an arid zone. This provisional statement of results describes the geomorphology of the wadi, the settlement archaeology, ceramic dating evidence, palaeoeconomic data (including palynological evidence), wadi wall technology and typology.
The description and analysis of particle size distributions using log skew Laplace distributions is a new technique designed to overcome various mathematical and computational problems associated with other approaches. This paper presents an application of the method. In particular, it describes fitting log skew Laplace distributions to modern and ancient shoreline sands from Lepcis Magna (near Horns), Tripolitania, with the purpose of discriminating between modern environments and so classifying the ancient samples. Satisfactory discrimination was not always achieved between some of the modern ‘calibration’ shoreline sand samples of known provenance — possibly as a result of the presence of multimodal distributions. One layer in the harbour-infill sequence, previously of unknown provenance, was shown to have collected at, or close to, an ancient shoreline which developed within the ancient harbour. The majority of the ‘ancient’ samples of unknown depositional environments which were excavated from exposures in the Romano-Libyan harbour-infill sands, were shown by this analysis to be of neither beach nor aeolian origin. This conclusion supports field observations which suggested that the greater part of the harbour-infill sequence represented reworked dune palaeosols, developing dune soils and fluvial and lagoonal facies.
The objective of this study was to determine the genetic parameters of methane (CH4) emissions and their genetic correlations with key production traits. The trial measured the CH4 emissions, at 5-min intervals, from 1225 sheep placed in respiration chambers for 2 days, with repeat measurements 2 weeks later for another 2 days. They were fed in the chambers, based on live weight, a pelleted lucerne ration at 2.0 times estimated maintenance requirements. Methane outputs were calculated for g CH4/day and g CH4/kg dry matter intake (DMI) for each of the 4 days. Single trait models were used to obtain estimates of heritability and repeatability. Heritability of g CH4/day was 0.29 ± 0.05, and for g CH4/kg DMI 0.13 ± 0.03. Repeatability between measurements 14 days apart were 0.55 ± 0.02 and 0.26 ± 0.02, for the two traits. The genetic and phenotypic correlations of CH4 outputs with various production traits (weaning weight, live weight at 8 months of age, dag score, muscle depth and fleece weight at 12 months of age) measured in the first year of life, were estimated using bivariate models. With the exception of fleece weight, correlations were weak and not significantly different from zero for the g CH4/kg DMI trait. For fleece weight the phenotypic and genetic correlation estimates were −0.08 ± 0.03 and −0.32 ± 0.11 suggesting a low economically favourable relationship. These results indicate that there is genetic variation between animals for CH4 emission traits even after adjustment for feed intake and that these traits are repeatable. Current work includes the establishment of selection lines from these animals to investigate the physiological, microbial and anatomical changes, coupled with investigations into shorter and alternative CH4 emission measurement and breeding value estimation techniques; including genomic selection.
Psychiatric in-patients are at high risk of suicide. Recent reductions in bed numbers in many countries may have affected this risk but few studies have specifically investigated temporal trends. We aimed to explore trends in psychiatric in-patient suicide over time.
A prospective study of all patients admitted to National Health Service (NHS) in-patient psychiatric care in England (1997–2008). Suicide rates were determined using National Confidential Inquiry and Hospital Episode Statistics (HES) data.
Over the study period there were 1942 psychiatric in-patient suicides. Between the first 2 years of the study (1997, 1998) and the last 2 years (2007, 2008) the rate of in-patient suicide fell by nearly one-third from 2.45 to 1.68 per 100 000 bed days. This fall in rate was observed for males and females, across ethnicities and diagnoses. It was most marked for patients aged 15–44 years. Rates also fell for the most common suicide methods, particularly suicide by hanging on the ward (a 59% reduction). Although the number of post-discharge suicides fell, the rate of post-discharge suicide may have increased by 19%. The number of suicide deaths in those under the care of crisis resolution/home treatment teams has increased in recent years to approximately 160 annually.
The rate of suicide among psychiatric in-patients in England has fallen considerably. Possible explanations include falling general population rates, changes in the at-risk population or improved in-patient safety. However, a transfer of risk to the period after discharge or other clinical settings such as crisis resolution teams cannot be ruled out.
During a series of submersible surveys of the Shiribeshi Seamount, northern Sea of Japan, by the remotely-operated vehicle (ROV) ‘Dolphin 3K’ and the human-occupied vehicle (HOV) ‘Shinkai 2000’ in July 2001, dense patches of golden skate eggs were observed. Given the lack of information for this species, an analysis was performed to estimate the abundance of the eggs and to ascertain if any patterns could be determined from the distribution of eggs on the sea-floor as recorded by the ROV and HOV video cameras. Eggs, including some with viable embryos, were found on only one of four ROV benthic transect surveys and one crewed submersible dive in the same location. The site where eggs were laid was relatively small and appeared to have been revisited through time. This work is part of an ongoing collaborative effort between East Stroudsburg University and the Marine Biodiversity Research Programme at the Japan Agency for Marine–Earth Science and Technology to characterize the midwater and benthic deep-sea faunas around Japan.
The use of bright-field transmission electron microscopy 3-D tomographic reconstruction allowed us to localize the synthesized nanostructures within the pores of mesoporous nanotemplates. Using this technique, we found that noble metal impregnation resulted in the inclusion of metal nanostructures within the SBA-15 mesoporous silica hexagonal pores (from nanoclusters to nanowires). The method allowed corroborating if the nanostructures were synthesized inside the pores or if they were alternatively on the nanotemplate aggregates exterior surface.
Single crystal NiSi2 films of type A and type B orientations with thicknesses ranging from 70–600Å have been grown on (111), n-type Si substrates. TEM and channeling measurements indicate that these films are of excellent epitaxial quality with uniform orientations over the entire range of observation. HRTEM studies show regular and atomically abrupt interfaces for both NiSi2 orientations with occasional localized planar defects. I-V and photoresponse measurements of the Schottky barrier heights(SBH) of the type A films yield consistent values of 0.62±.01eV. However, for type B films I-V measurements give a SBH of 0.69±.01eV while the photoresponse results give 0.77±.05eV. This discrepancy can be explained quantitatively by a phenomenological model in which a small percentage of low barrier height regions is incorporated into the type B films.