A pencil distributed finite difference code for strongly turbulent wall-bounded flows

We present a numerical scheme geared for high performance computation of wall-bounded turbulent flows. The number of all-to-all communications is decreased to only six instances by using a two-dimensional (pencil) domain decomposition and utilizing the favourable scaling of the CFL time-step constraint as compared to the diffusive time-step constraint. As the CFL condition is more restrictive at high driving, implicit time integration of the viscous terms in the wall-parallel directions is no longer required. This avoids the communication of non-local information to a process for the computation of implicit derivatives in these directions. We explain in detail the numerical scheme used for the integration of the equations, and the underlying parallelization. The code is shown to have very good strong and weak scaling to at least 64K cores

The role of the South Atlantic in the upper branch of the global thermohaline circulation

The global thermohaline ocean circulation moderates the temperatures over Northern Europe. The transport of heat, mass and salt between different ocean basins is an important part of this link. The pathways of interocean exchange of thermocline and intermediate waters in the South Atlantic Ocean have been investigated with a Lagrangian particle following technique in the ocean model OCCAM. More than 90\% of the flow toward the North Atlantic originates from the Indian Ocean via leakage from the Agulhas Current system. Several observational studies have indicated a dominant role in the transport toward the North Atlantic for intermediate water or for direct inflow from Drake Passage. The section averaged water mass transports in OCCAM are largely in agreement with these observational estimates, in apparent contradiction with the Lagrangian path. The reason for this discrepancy is that south of Africa the net mass flux consists of opposing, and in the thermocline layer nearly compensating, east- and westward flows. In the thermocline layer, part of the westward flow connects with the cross-equatorial flow in the Atlantic, while the eastward flow is partly derived from upwelled intermediate and thermocline water that originates from Drake Passage. It is arguable to draw conclusions about the flow pathways from integrated mass fluxes across ocean sections, especially when these contain opposing flows in the same density classes. Air-sea fluxes of heat and freshwater induce transformations between different water masses. These water mass transformations are calculated for the South Atlantic with OCCAM. The uncertainty of the estimates of water mass transformations from several observational datasets is at least 10 Sv, largely caused by the uncertainties in heat fluxes. Subduction generates teleconnections between the South Atlantic and remote areas where these water masses re-emerge in the mixed layer and has been analyzed with a Lagrangian trajectory analysis. The subducted Antarctic Intermediate Water and Subantarctic Mode Water re-emerge mainly in the Antarctic Circumpolar Current further downstream. Lighter waters re-emerge in the eastern Tropical Atlantic. The impact of the South Atlantic on the upper branch of the thermohaline circulation is rather indirect: water is significantly transformed by air-sea fluxes and mixing in the South Atlantic, but most of it re-emerges and subducts again further downstream. The leakage of water from three Agulhas rings has been studied in a high resolution global ocean model using a Lagrangian particle following technique. A bowl shaped ring boundary that reaches a radius of 140\,km and a depth of 800\,m separates regions of fast and slow leakage. A shallow secondary circulation, caused by subinertial motions due to surface cooling, enhances leakage in the upper 150\,m. Most of the intermediate waters that cross the equatorial Atlantic as part of the return flow for North Atlantic Deep Water were subducted in the southeast Indian Ocean. Less than 20\% comes directly from Drake Passage without looping into the Indian Ocean; the majority being provided by Agulhas leakage. Most of the intermediate waters that form in the South Atlantic do not follow the South Atlantic/Indian Ocean supergyre, but remain within the Antarctic Circumpolar Current, and gradually transform into Circumpolar Deep Water by diapycnal mixing

Biomechanical comparison of compression force and insertion torque in the implantation of three types of compression screws

A disintegrin and metalloproteinase domain 10 (ADAM10) is a metalloprotease involved in cleavage of various cell surface molecules, such as adhesion molecules, chemokines, and growth factor receptors. Although we have previously shown an association of ADAM10 expression with atherosclerotic plaque progression, a causal role of ADAM10 in atherosclerosis has not been investigated. Bone marrow from conditional knockout mice lacking Adam10 in the myeloid lineage or from littermate controls was transplanted into lethally irradiated low density lipoprotein receptor Ldlr(-/-) mice on an atherogenic diet. Myeloid Adam10 deficiency did not affect plaque size, but it increased plaque collagen content. Matrix metalloproteinase 9 and 13 expression and matrix metalloproteinase 2 gelatinase activity were significantly impaired in Adam10-deficient macrophages, whereas their capacity to stimulate collagen production was unchanged. Furthermore, relative macrophage content in advanced atherosclerotic lesions was decreased. In vitro, Adam10-deficient macrophages showed reduced migration toward monocyte chemoattractant protein-1 and transmigration through collagen. In addition, Adam10-deficient macrophages displayed increased anti-inflammatory phenotype with elevated IL-10, and reduced production of proinflammatory tumor necrosis factor, IL-12, and nitric oxide in response to lipopolysaccharide. These data suggest a critical role of Adam10 for leukocyte recruitment, inflammatory mediator production, and extracellular matrix degradation. Thereby, myeloid ADAM10 may play a causal role in modulating atherosclerotic plaque stabilit

Investigation of calcium carbonate precipitated in the presence of alkanols

The influence of myristyl alcohol (CH3(CH2)13OH), cetyl alcohol (CH3(CH2)15OH) and behenyl alcohol (CH3(CH2)21OH) on the structure, morphology, size and surface properties of calcium carbonate (CaCO3) has been investigated. Changes in the nature of the washing solvent, in the CnOH/Ca2+ and CO32−/Ca2+ molar ratios and in temperature have been also evaluated. The sole polymorph produced was rhombohedral calcite. At room temperature, while microspheres composed of submicrocubes were produced at a high molar ratio CO32−/Ca2+ and low CH3(CH2)15OH concentration, a stoichiometric molar ratio CO32−/Ca2+ and high CH3(CH2)15OH concentration induced the formation of microcubes and microboxes. In the presence of this alkanol (12 % molar) a significant enhancement of the water contact angle (ca. 40 °) resulted in a sample obtained with a stoichiometric CO32−/Ca2+ ratio. These results emphasize the key role played by the three non-ionic surfactants in the formation of materials with variable crystal shape and wettability and thus technological interest for a range of applications.This work was financially supported by Fundacao para a Ciencia e a Tecnologia (FCT) (contracts PTDC/CTM-BPC/112774/2009, Pest-C/CTM/LA0011/2013, Pest-OE/QUI/UI0616/2014, PTDC/FIS/115048/2009 and PTDC/CTM-BIO/1814/2012) and COST Action MP1202 "Rational design of hybrid organic-inorganic interfaces". M. Fernandes thanks FCT for a grant (SFRH/BPD/78919/2011). The authors thank Nuno Oliveira (3B's Research Group of the University of Minho, Portugal) for the contact angle measurements, and Professor Hugh Burrows (Department of Chemistry of the University of Coimbra, Portugal) for fruitful discussions