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A comprehensive quasi-static and dynamic ball bearing model is described using many enhanced features, including novel calculations of the contact angle variations and ball–race sliding speeds in two directions, accounting for race curvature, pivoting effects and gyroscopic effects, appropriate lubricant rheology, and sliding forces (driving the balls against miscellaneous braking forces and moments such as, for example, the hydrodynamic rolling force). Ball–cage impact forces and cage-guiding ring forces are also considered, leading to a set of six dynamic differential equations to consider for each ball and three dynamic differential equations for the cage, where movement is assumed to be restricted to one plane. Quasi-static calculations can be undertaken by neglecting the cage and setting the accelerations of each degree of freedom of the ball to zero. New analytical or curve-fitted models are also provided using the mean values of sliding speed and viscosity to calculate sliding forces and moments, avoiding the use of contact slices with some useful relationships derived for calculating the rolling line locations, bearing torque, and dissipated bearing power. Several examples of calculated results are given and compared to available numerical or experimental results published in the literature. Finally, a new tool developed in-house is proposed for predicting many properties, particularly of interest at high speed, including the ball bearing torque, power loss, risk of smearing, and risk of cage failure. [ABSTRACT FROM AUTHOR]

Advanced ball bearing simulations require the use of accurate tribological models, starting with the calculation of the ball-race contact load and pressure in potentially truncated contacts. Ball—cage and cage—guiding ring contact stiffness models are suggested using the Hertzian contact stiffness and/or a structural stiffness. The central ball-race film thickness, a hydrodynamic rolling force, and normal load increase are calculated using relationships respecting miscellaneous lubrication regimes, including iso-viscous-rigid or piezo-viscous-elastic. A drag force acting at the ball center is included, and its magnitude discussed for claiming that the contribution from drag to the final rolling resistance is smaller than the one from hydrodynamic rolling acting at the ball-race contact. The central film thickness and sliding speed are used for defining shear rate, shear stress, and, hence, final sliding force, using a nonlinear visco-elastic-plastic lubricant rheological model including viscosity, elastic lubricant shear modulus, and limiting shear stress, which are all functions of the pressure and temperature. Elastic effects are approximated using a simple nonlinear visco-plastic model with apparent viscosity. The temperature is defined as the sum of the operating temperature and several other sources of temperature increase. It is observed that when adopting Roelands viscosity model and a simple nonlinear visco-plastic model, the final lubricant traction coefficient and its gradient with respect to sliding speed decrease as the rolling speed increases, mostly reducing the need for a lubricant elastic shear modulus. Appropriate experimental results are highlighted to support these analytical models. [ABSTRACT FROM AUTHOR]

Indents perturb the pressure and stress distribution and increase the failure risk of rolling element bearings. A numerical study of the pressure perturbation is proposed. An existing dry contact model is extended to account for the indent shoulder influence and the pressure collapse in deeper indents. Moreover, results for pure rolling lubricated contacts are presented. Finally; the ellipticity influence is studied for both dry and lubricated contacts. Keywords: indentation, contamination, pollution, fatigue, rolling bearing life

A novel analytical approach is proposed, uniform for ball and roller bearings, which takes into account 5 relative race displacements (3 translations: dx, dy, and dz, and 2 tilting angles: d[[Theta].sub.y] and d[[Theta].sub.z]) to provide simple analytical relationships for calculating directly the resulting 3 bearing loads: [F.sub.x], [F.sub.y], and [F.sub.z] as well as the 2 tilting moments: [M.sub.y]. and [M.sub.z]. A full coupling between all these displacements and forces is considered. The maximum rolling element load [Q.sub.max], the load distribution Q([Psi]) and the 3-D rolling element load distribution dQ([pounds], x[prime]) at each roller-race contact slice are also given analytically. It will therefore be possible for bearing users, willing to study for themselves a complete statically indeterminate systems including shafts, housing and bearings, to do such calculations using accurate nonlinear bearing forces-displacements relationships suggested in this paper and to predict easily bearing and other system components performances. This approach can also be implemented in any nonlinear Finite Element Analysis (F.E.A.) package for describing a bearing element connecting the shaft to the housing for example. It completes, therefore, the F.E.A. library of elements.

The Rockall Trough is one of the main conduits for warm Atlantic Water to the Nordic Seas. Ocean heat anomalies, originating from the eastern subpolar gyre, are known to influence Arctic sea ice extent, marine ecosystems, and continental climate. Knowledge of the transport through this basin has previously been limited to estimates from hydrographic sections which cannot characterize the intra‐annual and multiannual variability. As part of the Overturning in the Subpolar North Atlantic Programme (OSNAP), a mooring array was deployed in the Rockall Trough in order to obtain the first continuous measurements of transport. Here, we define the methodology and the errors associated with estimating these transports. Results show a 4‐year mean northward transport of 6.6 Sv (1 Sv = 106 m3/s) by the North Atlantic Current (NAC) in the east and interior of the Rockall Trough (2014–2018). A mean transport of −2.0 Sv (southward) is observed in the west of the basin, which could be part of a recirculation around the Rockall Plateau. The 90‐day low‐pass‐filtered transport shows large subannual and interannual variability (−1.6 to 9.1 Sv), mostly resulting from changes in the midbasin geostrophic transport. Satellite altimetry reveals the periods of low and high transport are associated with significant changes in the Rockall Trough circulation. There is a detectable seasonal signal, with the greatest transport in spring and autumn.Plain Language Summary: There is mounting evidence that the North Atlantic Current (eastward extension of the Gulf Stream) heavily influences the European and Arctic climate. To adequately measure this current and understand its dynamics, an array of underwater instruments was deployed in the Rockall Trough, a remote region of the eastern North Atlantic. Over a 4‐year period, these instruments continuously collected measurements of temperature, salinity, pressure, and velocity data. Analysis of these data provides a new and more accurate description of the North Atlantic Current in this region. This study reveals a surprisingly large variability in the eastern North Atlantic circulation. The combined analysis of underwater measurements and satellite data indicates that this variability is due to changes of the North Atlantic Current system.Key Points: For the first time, the strength of the North Atlantic Current (NAC) has been measured continuously for four years in the Rockall TroughDuring 2014 to 2018, about half the amount of warm water travelling northwards towards the Arctic Ocean flows through the Rockall TroughHigh northward transport periods are characterized by a strong NAC jet in the Rockall Trough, weak transport by mesoscale eddy activity [ABSTRACT FROM AUTHOR]

The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism of heat, freshwater, and carbon redistribution in the climate system. The precept that the AMOC has changed abruptly in the past, notably during and at the end of the last ice age, and that it is "very likely" to weaken in the coming century due to anthropogenic climate change is a key motivation for sustained observations of the AMOC. This paper reviews the methodology and technology used to observe the AMOC and assesses these ideas and systems for accuracy, shortcomings, potential improvements, and sustainability. We review hydrographic techniques and look at how these traditional techniques can meet modern requirements. Transport mooring arrays (TMAs) provide the "gold standard" for sustained AMOC observing, utilizing dynamic height, current meter, and other instrumentation and techniques to produce continuous observations of the AMOC. We consider the principle of these systems and how they can be sustained and improved into the future. Techniques utilizing indirect measurements, such as satellite altimetry, coupled with in situ measurements, such as the Argo float array, are also discussed. Existing technologies that perhaps have not been fully exploited for estimating AMOC are reviewed and considered for this purpose. Technology is constantly evolving, and we look to the future of technology and how it can be deployed for sustained and expanded AMOC measurements. Finally, all of these methodologies and technologies are considered with a view to a sustained and sustainable future for AMOC observation. [ABSTRACT FROM AUTHOR]

The Deep Western Boundary Current in the subpolar North Atlantic is the lower limb of the Atlantic Meridional Overturning Circulation and a key component of the global climate system. Here, a mooring array deployed at 60°N in the Irminger Sea, between 2014 and 2016, provides the longest continuous record of total Deep Western Boundary Current volume transport at this latitude. The 1.8‐year averaged transport of water denser than σθ = 27.8 kg/m3 was −10.8 ± 4.9 Sv (mean ± 1 std; 1 Sv = 106 m3/s). Of this total, we find −4.1 ± 1.4 Sv within the densest layer (σθ > 27.88 kg/m3) that originated from the Denmark Strait Overflow. The lighter North East Atlantic Deep Water layer (σθ = 27.8–27.88 kg/m3) carries −6.5 ± 7.7 Sv. The variability in transport ranges between 2 and 65 days. There is a distinct shift from high to low frequency with distance from the East Greenland slope. High‐frequency fluctuations (2–8 days) close to the continental slope are likely associated with topographic Rossby waves and/or cyclonic eddies. Here, perturbations in layer thickness make a significant (20–60%) contribution to transport variability. In deeper water, toward the center of the Irminger Basin, transport variance at 55 days dominates. Our results suggest that there has been a 1.8 Sv increase in total transport since 2005–2006, but this difference can be accounted for by a range of methodological and data limitation biases. Plain Language Summary: A network of currents in the Atlantic Ocean plays an important role in the global climate system, redistributing heat, salt, nutrients, and carbon around the globe. It is made up of a northward flow of warm, salty water in the upper layers of the Atlantic, and a deep, southward flow of colder, denser water. Dense water is formed at high latitudes when surface waters release heat to the atmosphere and sink toward the seafloor. This forms the Deep Western Boundary Current that moves southward to the east of Greenland. Knowing how much water is carried and whether the current is stable is vital to our understanding of global climate. Using measurements of temperature, salinity, and current speed from instruments deployed between 2014 and 2016, we find that the Deep Western Boundary Current transports on average 10.8 × 106 m3 of water a second. This transport varies in time. It increases and decreases from day to day and month to month. Eddies, waves, and other ocean currents all contribute to these fluctuations. Our results suggest that transport has increased since 2005–2006, but it is possible to account for this change by considering the limitations of previous data sets and the methods used to calculate the transport. Key Points: Volume transport of the Deep Western Boundary Current in the Irminger Sea between 2014 and 2016 was ‐10.8 +/‐ 4.9 SvTransport variability shifts from high (2‐8 days) to low (55 days) frequencies with distance down slopeNo significant long‐term trend in transport was identified [ABSTRACT FROM AUTHOR]

Abstract: Repeat glider sections obtained during 2014–2016, as part of the Overturning in the Subpolar North Atlantic Program, are used to quantify the circulation and transport of North Atlantic Current (NAC) branches over the Rockall Plateau. Using 16 glider sections collected along 58°N and between 21°W and 15°W, absolute geostrophic velocities are calculated, and subsequently the horizontal and vertical structure of the transport are characterized. The annual mean northward transport (± standard deviation) is 5.1 ± 3.2 Sv over the Rockall Plateau. During summer (May to October), the mean northward transport is stronger and reaches 6.7 ± 2.6 Sv. This accounts for 43% of the total NAC transport of upper‐ocean waters (σO<27.55 kg/m3) estimated by Sarafanov et al. (2012, https://doi.org/10.1029/2011JC007572) along 59.5°N, between the Reykjanes Ridge and Scotland. Two quasi‐permanent northward flowing branches of the NAC are identified: (i) the Hatton Bank Jet (6.3 ±  2.1 Sv) over the eastern flank of the Iceland Basin (20.5°W to 18.5°W) and (ii) the Rockall Bank Jet (1.5 ±  0.7 Sv) over the eastern flank of the Hatton‐Rockall Basin (16°W to 15°W). Transport associated with the Rockall Bank Jet is mostly depth independent during summer, while 30% of the Hatton Bank Jet transport is due to vertical geostrophic shear. Uncertainties are estimated for each individual glider section using a Monte Carlo approach, and mean uncertainties of the absolute transport are less than 0.5 Sv. Although comparisons with altimetry‐based estimates indicate similar large‐scale circulation patterns, altimetry data do not resolve small mesoscale current bands in the Hatton‐Rockall Basin which are strongly needed for the right transport estimates. [ABSTRACT FROM AUTHOR]

Hydrodynamic effects are responsible for a dimensionless load increase ΔW (relative to the load WHertz calculated in a dry contact) calculated primarily as a function of the dimensionless rolling element–race geometrical interference Δ/Rx, dimensionless speed, and radii ratio. The final load (W = WHertz + ΔW) is therefore never nil, even in cases when the geometrical interference is negative or nil, which corresponds to a Hertzian load nil. The final load is calculated by solving the following dimensionless algebraic relationship: , where δ is the elastic deformation (function of the load and radii ratio) calculated using a Hertzian relationship and H is the dimensionless film thickness, again a function of the load and radii ratio but also dimensionless speed and material parameters, the latter being included in piezoviscous-rigid (PVR) and piezoviscous-elastic (PVE, also called elastohydrodynamic or EHD) film thickness relationships. Advanced new curve-fitted relationships are also suggested in this article for calculating miscellaneous Hertzian parameters, such as contact dimensions, maximum pressure, and deformation. A detailed survey of several film thickness relationships was conducted covering different lubrication regimes: isoviscous-rigid (IVR, found at low dimensionless load and speed), PVR, and EHD (high dimensionless load and low dimensionless speed). It has been shown that the IVR regime prevails when Δ/Rx is negative or nil and the radii ratio is large (as found in roller bearings); hence, an IVR approach can be suggested for numerically calculating ΔW. A powerful set of curve-fitted relationships is then suggested for easily calculating ΔW. A simplified approach based on a previously published analytical solution of ΔW applicable to line contact (LC) but used here in a sliced point contact (PC) was also tested after having demonstrated that LC results (for H and δ) can be used in slices for retrieving (within 10%) PC results on H and δ. This result is surprising given that the exponents used for calculating H and δ differ substantially in LC versus PC. In addition, a new IVR thermal correction factor was developed for better calculating the film thickness. Although very small, ΔW can be responsible for a moderate bearing preload and torque increase, calculated using previously published IVR hydrodynamic rolling forces when the dimensionless speed is high and the bearing clearance is small or nil. Hydrodynamic effects, both normal and tangential to the contact, also contribute to the roller speed decreases in the unloaded zone of a bearing, so there is no need to consider large drag force to explain this drop. Previously published roller drag force relationships may therefore overestimate these forces when calibrated versus tests by not considering the rolling element–race hydrodynamic effect described herein. [ABSTRACT FROM AUTHOR]

NASA and the French space agency, CNES, with contributions from the Canadian Space Agency (CSA) and United Kingdom Space Agency (UKSA) are developing new wide swath altimetry technology that will cover most of the world's ocean and surface freshwater bodies. The proposed Surface Water and Ocean Topography (SWOT) mission will have the capability to make observations of surface water (lakes, rivers, wetland) heights and measurements of ocean surface topography with unprecedented spatial coverage, temporal sampling, and spatial resolution compared to existing technologies. These data will be useful for monitoring the hydrologic cycle, flooding, and characterizing human impacts on a changing environment. The applied science community is a key element in the success of the SWOT mission, demonstrating the high value of the science and data products in addressing societal issues and needs. The SWOT applications framework includes a working group made up of applications specialists, SWOT science team members, academics and SWOT Project members to promote applications research and engage a broad community of potential SWOT data users. A defined plan and a guide describing a program to engage early adopters in using proxies for SWOT data, including sophisticated ocean and hydrology simulators, an airborne analogue for SWOT (AirSWOT), and existing satellite datasets, are cornerstones for the program. A user survey is in development and the first user workshop was held in 2015, with annual workshops planned. The anticipated science and engineering advances that SWOT will provide can be transformed into valuable services to decision makers and civic organizations focused on addressing global disaster risk reduction initiatives and potential science-based mitigation activities for water resources challenges of the future. With the surface water measurements anticipated from SWOT, a broad range of applications can inform inland and coastal managers and marine operators of terrestrial and oceanic phenomena relevant to their work. [ABSTRACT FROM AUTHOR]

Analytical relationships for calculating three rolling element bearing loads (Fx, Fy, and Fz) and two tilting moments (My and Mz) as a function of three relative race translations (dx, dy, and dz) and two relative race tilting angles (dθy and dθz) have been given in a previous paper. The previous approach was suggested for any rolling element bearing type, although it has been recognized that the assumption of a constant rolling elementrace contact angle is not well supported by deep groove ball bearings (DGBB) or angular contact ball bearings (ACBB). The new approach described in this paper addresses the latter weaknesses by accounting for the variation of the contact angle on the most loaded ball and also shows that misalignment effects on spherical roller bearing (SRB) loads are negligible. Comparisons between the simplified approach (option 1) and the "enhanced" numerical approach (option 2, which requires a summation of the load components on each ball with the appropriate contact angle included) is made, showing a good correlation as long as the relative misalignment remains reasonable or occurs in the plane corresponding to maximum radial displacement. Option 2 can, however, be recommended since it is easy to program and quite accurate at any misalignment level. Other pros and cons of both options are described. As in the previous paper, a full coupling between all displacements and forces, as well as roller and raceway crown radii, are considered, meaning that Hertzian point contact stiffness is used in roller bearings at low load with a smooth transition toward Hertzian line contact as the load increases. This approach is particularly recommended for programming the rolling element bearing behavior in any finite element analysis or multibody system dynamic tool, since only two nodes are considered: one for the inner race (IR) center, usually connected to a shaft, and another node for the outer race (OR) center, connected to the housing. [ABSTRACT FROM AUTHOR]

An enhanced analytical approach is suggested for calculating three rolling element bear-ing loads Fx, Fy, and Fz as well as the two tilting moments My and Mz as a function of five relative race displacements: three translations dx, dy, and dz, and two tilting angles dθy and dθz. A full coupling between all these displacements and forces is considered. This approach is particularly recommended for programming the rolling element bearing behavior in any finite element analysis or multibody system dynamic tool, since only two nodes are considered: one for the inner race center, usually connected to a shaft, and another node for the outer race center, connected to the housing. Also, roller and race-way crown radii are considered, meaning that Hertzian point contacts stiffness can be used at low load with a smooth transition toward Hertzian line contact as the load increases. This approach can be used for describing any rolling element bearing type when neglecting centrifugal and gyroscopic effects and applying the approximation of a constant ball-race contact angle. Deep groove ball bearings (whose contact angle sign follows the sign of the applied bearing axial force) or other ball bearings or spherical roller bearing operating under large misalignment may not support such approximations. [ABSTRACT FROM AUTHOR]

This article presents a brief overview of how the stress risk integrals of indented contacts are combined to calculate a rolling element bearing life and some experimental data concerning measured indentation. The possibility of predicting surface indentation and bearing life from normalized contamination standards is discussed. [ABSTRACT FROM AUTHOR]

Based on previous studies concerning pressure perturbations due to indents in dry and elastohydrodynamic lubrication contacts, this article presents the indented contact stress distribution and risk integral calculations. Different stress criteria are discussed and an equation predicting the risk integral is proposed. [ABSTRACT FROM AUTHOR]

The deep outer margin of the Gulf of Lions and the adjacent basin, in the western Mediterranean Sea, are regularly impacted by open-ocean convection, a major hydrodynamic event responsible for the ventilation of the deep water in the western Mediterranean Basin. However, the impact of open-ocean convection on the flux and transport of particulate matter remains poorly understood. The variability of water mass properties (i.e., temperature and salinity), currents, and particle fluxes were monitored between September 2007 and April 2009 at five instrumented mooring lines deployed between 2050 and 2350-m depth in the deepest continental margin and adjacent basin. Four of the lines followed a NW- SE transect, while the fifth one was located on a sediment wave field to the west. The results of the main, central line SC2350 ("LION") located at 42°02.5' N, 4°41' E, at 2350m depth, show that open-ocean convection reached midwater depth (≈ 1000-m depth) during winter 2007-2008, and reached the seabed (≈ 2350-m depth) during winter 20082009. Horizontal currents were unusually strong with speeds up to 39 cm s-1 during winter 2008-2009. The measurements at all 5 different locations indicate that mid-depth and near-bottom currents and particle fluxes gave relatively consistent values of similar magnitude across the study area except during winter 2008-2009, when near-bottom fluxes abruptly increased by one to two orders of magnitude. Particulate organic carbon contents, which generally vary between 3 and 5 %, were abnormally low (≤ 1%) during winter 20082009 and approached those observed in surface sediments (≈ 0.6 %). Turbidity profiles made in the region demonstrated the existence of a bottom nepheloid layer, several hundred meters thick, and related to the resuspension of bottom sediments. These observations support the view that open-ocean deep convection events in the Gulf of Lions can cause significant remobilization of sediments in the deep outer margin and the basin, with a subsequent alteration of the seabed likely impacting the functioning of the deep-sea ecosystem. [ABSTRACT FROM AUTHOR]

Cap de Creus Canyon (CCC) is known as a preferential conduit for particulate matter leaving the Gulf of Lion continental shelf towards the slope and the deep basin, particularly in winter when storms and dense shelf water cascading coalesce to enhance the seaward export of shelf waters. During the CASCADE (CAscading, Storm, Convection, Advection and Downwelling Events) cruise in March 2011, deployments of recording instruments within the canyon and vertical profiling of the water column properties were conducted to study with high spatial-temporal resolution the impact of such processes on particulate matter fluxes. In the context of a mild and wet 2010-2011 winter, no remarkable dense shelf water formation was observed. On the other hand, the experimental setup allowed to study the impact of E-SE storms on the hydrographical structure and the particulate matter fluxes in the CCC. The most remarkable feature in terms of sediment transport was a period of dominant E-SE winds from 12 to 16 March, including two moderate storms of significant wave heights=4-4.5m. During this period, a plume of freshened, relatively cold and turbid water flowed at high speeds along the southern flank of CCC in an approximate depth range of 150-350m. The density of this water mass only reached ~28.78 kgm-3, indicating that it did not cascade into the canyon and that merely down-welled into it forced by the accumulation of seawater along the coast during the storms and by the subsequent strong cyclonic circulation induced over the shelf. Suspended sediment load in this turbid intrusion was comparable at three heights above bottom where turbidimeters were installed (10, 75 and 115m above bottom) on the southern canyon flank and oscillated between 10 and 50mg L-1. Current speeds were also comparable in the depth range profiled by ADCPs (40 to 150mab) and reached values up to 90 cm s-1 during the peak of the strongest storm (13 March, Hs = 4.5m). Sediment transport at 75mab on the southern canyon flank was estimated at 1-1.5 t m-2 for the entire deployment while very close to the bottom (5m above) in the canyon head it was less than 0.6 t m-2 during the same period. We provide a rough estimation of 105 t of sediment transported through the canyon along its southern wall during a 3 day-long period of storm-induced downwelling. Following the veering of the wind direction (from SE to NW) on 16 March, down-welling ceased, currents inside the canyon reversed from down to up-canyon, and the turbid shelf plume was evacuated from the canyon, most probably flowing along the southern canyon flank and being entrained by the general SW circulation after leaving the canyon confinement. This study highlights that remarkable sediment transport occurs in the CCC, and particularly along its southern flank, even during mild and wet winters, in absence of cascading and under limited external forcing. The sediment transport associated to eastern storms like the ones described in this paper tends to enter the canyon by its downstream flank, partially affecting the canyon head region. Sediment transport during these events is not constrained near the seafloor but distributed in a depth range of 200-300m above the bottom. Our paper broadens the understanding of the complex set of atmosphere-driven sediment transport processes acting in this highly dynamic area of the northwestern Mediterranean Sea. [ABSTRACT FROM AUTHOR]

The deep outer margin of the Gulf of Lions and the adjacent basin, in the Western Mediterranean Sea, are regularly impacted by open-ocean convection, a major hydrodynamic event responsible for the ventilation of the deep water in the Western Mediterranean Basin. However, the impact of open-ocean convection on the flux and transport of particulate matter remains poorly understood. The variability of water mass properties (i.e. temperature and salinity), currents, and particle fluxes was monitored between September 2007 and April 2009 at five instrumented mooring lines deployed between 2050 and 2350 m-depth in the deepest continental margin and adjacent basin. Four of the lines followed a NW-SE transect, while the fifth one was located on a sediment wave field to the west. The results of the main, central line SC2350 ("LION"), located at 42° 02.5′ N and 4° 41′ E, at 2350 m-depth, show that open-ocean convection reached mid-water depth (≈1000 m-depth) during winter 2007-2008, and reached the seabed (≈2350 m-depth) during winter 2008-2009. Horizontal currents were unusually strong with speeds up to 39cms-1 during winter 2008-2009. The measurements at all 5 different locations indicate that mid-depth and near-bottom currents and particle fluxes gave relatively consistent values of similar magnitude across the study area except during winter 2008-2009, when near-bottom fluxes abruptly increased by one to two orders of magnitude. Particulate organic carbon contents, which generally vary between 3 and 5 %, were abnormally low (≤1 %) during winter 2008-2009 and approached those observed in surface sediments (≈0.6 %). Turbidity profiles made in the region demonstrated the existence of a bottom nepheloid layer, several hundred meters thick, and related to the resuspension of bottom sediments. These observations support the view that open-ocean deep convection events in the Gulf of Lions can cause significant remobilization of sediments in the deep outer margin and the basin, with a subsequent alteration of the seabed likely impacting the functioning of the deep-sea ecosystem. [ABSTRACT FROM AUTHOR]

The stress based life model described in Paper I was calibrated using a large database of experimental results from a global quality audit test program as well as special development tests conducted for this validation effort. All tests used in the calibration of the new model were case carburized or through hardened tapered roller bearings. The initial model comparison to test results showed very good correlation with a median ratio of test life to calculated life very close to one. Higher accuracy of the stress based model compared to the traditional factor based method was also demonstrated by narrower confidence bands (less data scatter). Validation testing of case carburized tapered roller bearings as well as through hardened spherical roller bearings was also conducted under expanded test conditions beyond those utilized in the quality audit test program (i.e., high and low load, high and low λ, imposed misalignment, and heavy inner ring interference fits). Although the median ratio of relative life for the validation testing showed the stress based method to be conservative and well above one, the stress based method still showed better accuracy than the traditional factor based method as well as narrower confidence bands for this additional body of experimental data. The conservative results can be explained by use of high quality steel and manufacturing processes in a prototype facility and not series production equipment as was the case with the quality audit database. [ABSTRACT FROM AUTHOR]

Rolling contact bearing life is calculated using stresses calculated at the surface and in the volume. Surface stresses account for profile and misalignment as well as asperity deformations. Sub-surface stresses are calculated beneath the asperities (for defining the life of the surface) and deeper in the volume for calculating the life of the volume. The stress-life criterion adopted is the Dang Van one in which the local stabilized shear stress is compared to the material endurance limit defined as a function of the hydrostatic pressure (itself a function of the contact pressure) but also residual stresses and hoop stresses (due to fit). A stress-life exponent c, of the order of 4 (instead of 34/3 in the standard Lundberg and Palmgren model) is used for respecting a local load-life exponent of 10/3 at typical load levels. Life of any circumferential slices of the inner, outer, and roller is defined for obtaining the final bearing life. Trends showing how the bearing life varies as a function of the applied bearing load and Λ ratio (film thickness/RMS roughness height) are given. [ABSTRACT FROM AUTHOR]

Indents perturb the pressure and stress distribution and increase the failure risk. Existing theory for roughness deformation is extended to pure-rolling elastohydrodynamic lubrication indented contact pressure perturbations. First, a study of shallow indents is proposed, then it is modified to account for non-linear behavior of deeper indents. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea is a hotspot for climate change, and recent studies have reported its intense warming and salinification. In this study, we use an outstanding dataset relying mostly on glider endurance lines but also on other platforms to track these trends in the northwestern Mediterranean where deep convection occurs. Thanks to a high spatial coverage and a high temporal resolution over the period 2007-2017, we observed the warming (+0.06 [Formula: see text]C year[Formula: see text]) and salinification (+0.012 year[Formula: see text]) of Levantine Intermediate Water (LIW) in the Ligurian Sea. These rates are similar to those reported closer to its formation area in the Eastern Mediterranean Sea. Further downstream, in the Gulf of Lion, the intermediate heat and salt content were exported to the deep layers from 2009 to 2013 thanks to deep convection processes. In 2014, a LIW step of +0.3 [Formula: see text]C and +0.08 in salinity could be observed concomitant with a weak winter convection. Warmer and more saline LIW subsequently accumulated in the northwestern basin in the absence of intense deep convective winters until 2018. Deep stratification below the LIW thus increased, which, together with the air-sea heat fluxes intensity, constrained the depth of convection. A key prognostic indicator of the intensity of deep convective events appears to be the convection depth of the previous year.

The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as "open-sea convection". It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts.