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This study used model experiments to investigates hydraulic characteristics of flow at marguerite-shaped inlets with holes at the bottom of their lobes, known as modern marguerite-shaped inlets. This innovation reduces the swirling flow strength and improves the hydraulic performance of simple shaft spillways. Head–discharge relationships, flow circulation, threshold and critical submergence depths, and discharge coefficients are detailed for different flow regimes. The findings suggest that flow discharges through this type of inlet were approximately six, three, and two times greater than flow discharges through a simple shaft spillway, a circular piano key inlet, and a simple marguerite-shaped inlet, respectively. Increasing the outer length and height of inlets also uniformly distributed the flow around shaft spillways. The best hydraulic performance was observed in the inlets with an outer height of 1.25D and an outer length of 3.75D, where D is the diameter of the shaft spillway. Different equations, with high correlations and low errors, were derived to determine the threshold and critical submergence depths and the discharge coefficients for free and orifice flow regimes.

The primary target of present research is to examine the application of OHAM (optimal homotopy asymptotic method) for a nanofluid transport through Darcy Forchheimer space toward the stagnation region by comparing stretching and straining forces. The porous matrix is suspended with nanofluid, and the flow field is under inconsistent heat source/sink influence. The solutions of guiding boundary layer equations report that pattern of primary velocity profiles are inverted by stagnation region flow strength. Straightforward relation of Forchheimer number with heat transfer has also been observed when stagnation forces dominate stretching forces. The novelty of present article lies in vector form presentation to OHAM and in the comparative analysis of stretching and straining forces.

The tensile mechanical properties of silver nanowires produced by the polyol process and containing the characteristic pentatwinned microstructure are compared with single crystal nanowires prepared by template electrodeposition over a range of diameters, d, from 80 to 300 nm. The plastic flow strengths of both sets of nanowires show a significant size effect, ranging from about 400 MPa at d ? 300 nm to in excess of 1 GPa with d < 100 nm. The size effect is shown to follow the same empirical scaling law seen with other fcc structured metals. Transmission electron microscopy investigation of the deformed specimens found similar deformation structures in both classes of nanowire studied with relatively low dislocation densities found even after significant plastic strain. The deformed pentatwinned nanowires showed no evidence for any characteristic deformation structures associated with the twin boundaries running parallel to the nanowire axis. © 2021 Elsevier B.V. Henry Royce Institute: EP/P025021/1, EP/P025498/1, EP/R00661X/1, EP/S019367/1; Engineering and Physical Sciences Research Council, EPSRC: EP/J021229/1, EP/S009493/1; Royal Society; University of Manchester; China Scholarship Council, CSC The authors would like to acknowledge the support of the Engineering and Physical Sciences Research Council (EPSRC) through grants EP/J021229/1 and EP/S009493/1 . This work was also supported by the Henry Royce Institute for Advanced Materials , funded through EPSRC grants EP/R00661X/1 , EP/S019367/1 , EP/P025021/1 and EP/P025498/1 . HZ would like to thank the China Scholarship Council and the University of Manchester for financial support through a scholarship. ASE acknowledges financial support from the Royal Society.

Many studies in Europe have investigated the relationship between climatological variables and circulation patterns expressed by various classifications of circulation types. This study provides new insights based on an analysis of precipitation in the western (Bohemia—BOH) and eastern (Moravia and Silesia—M&S) parts of the Czech Republic with respect to the subjective classification of the Czech Hydrometeorological Institute and objective classification based on the flow strength, flow direction, and vorticity during the 1961–2020 period. Circulation types are investigated in regard to their contributions to the total precipitation, mean daily precipitation totals, and precipitation probability (daily totals ≥ 1.0 mm). Types with a westerly airflow and a trough over Central Europe exhibit the highest proportions in precipitation totals. Types with a cyclone over Central Europe, especially combined with a northwestern (BOH) or northeastern (M&S) airflow, result in the highest daily mean totals and precipitation probability. Types with a southwestern airflow transport more precipitation to BOH, while those with a northeastern airflow transport more precipitation to M&S, with a slight seasonal shift in the gradient axis between winter and summer. Circulation types under both classifications are examined from the perspective of their precipitation representation in BOH and M&S and the differences between these two regions. In addition, the suitability of both classifications for precipitation analysis is investigated.

The acoustic streaming which can facilitate the heat and mass transfer inside liquids is of great importance in ultrasonic processing. Most of previous investigations were mainly focused on the acoustic streaming induced by one dimensional (1D) ultrasound. In this paper, the flow field generated by 1D, 2D and 3D ultrasounds in a cubic box filled with water was investigated by numerical simulations. It is found that the jet flow emitted from the sound source is in the form of cylinder, vortex and wave, for 1D, 2D and 3D ultrasounds, respectively. When the ultrasonic dimension is increased, the flow becomes much stronger in the vicinity of the sound source but little weaker at the box center. By comparing the patterns of the flow generated by the ultrasounds of different dimensions, we demonstrate that 3D ultrasounds not only enhance the overall flow strength, but also effectively promote the uniformity of the flow and enlarge the size of vortices.

There are climatically important ocean flow systems in high latitudes, for example the East and West Greenland and Labrador Currents and Nordic Sea overflows in the North, and Antarctic Circumpolar Current in the South, for which it would be useful to know history of flow strength. Most of the sediment records under these flows contain evidence of supply from glacial sources, which has led to the supposition that fine sediment records, which in other settings provide evidence of vigour of flow from the sortable silt proxy, are fatally contaminated by unsorted glacial silt. It is suggested here that if the fine fraction ( 50%) because the two are not related. End member (EM) decomposition of several records yields variable results in terms of the relationship between EM ratios and grainsize parameters. Although such an approach can generate fine sediment parameters it does not provide a basis for deciding whether or not a record is acceptably current sorted and thus contains a valid flow speed proxy. Our proposed discrimination between current-sorted and unsorted fine fractions is applicable to all fine grained deposits, not only high-latitude deposits with coarse IRD. Examples from East Greenland, Faroe Bank Channel, Gardar Drift show mainly well sorted signatures. Amounts of coarse IRD range up to 60% with only those >50% having a consistent impact on sortable silt mean size. With the exception of a Southern Ocean site on the Antarctic continental rise where half the record is poorly sorted, the silt mean data are sufficiently well sorted to provide credible flow speed histories. This bodes well for the extraction of such histories from climatically important high-latitude flows such as the East Greenland Current.

Bedforms are thought to be a major cause of hydraulic roughness in channels. The geometry of the river bed, shaped by bars, dunes, and ripples, and the spatial and temporal distribution of these, influence the resulting roughness variations. Roughness is a fundamental parameter for understanding river flow behaviour by influencing sediment transport and water level.Quantification of roughness is challenging since it is not directly measurable in the field. It is therefore inferred from hydrological characteristics, -including water depth, water surface slope, flow velocity, discharge-, as well as morphological characteristics, -such as bedform height-, or derived from calibration of a hydraulic model.This study contributes to the elucidation of factors influencing hydraulic roughness, and its quantification from field data. Proper quantification of roughness and its spatiotemporal behavior will increase our knowledge in river behavior and will lead to improvement of river management strategies and operational models.In this research, three methods will be explored, to quantify the spatial distribution of hydraulic roughness in the field. We aim to state the importance of bed morphology for hydraulic roughness and we pursue the auxiliary aim to explore the spatial distribution of bedforms and roughness in our case study area river Waal, the Netherlands.Method 1 uses the St. Vernant equations (better known as the Chezy equations) to quantify roughness, with as input among others flow velocity, bed slope and water surface slope. This value is seen as the ‘true’ roughness of the river system. Method 2 is a traditionally often used method, where form roughness is obtained from dune characteristics such as height and length via empirical predictors. Method 3 makes use of characteristics of the bed itself, not strictly related to 2D bedform geometry, specifically the inclination of the streamwise local elevation profile, i.e. local topographic leeside angle. Doing so eliminates the necessity of defining dune characteristics, and therefore taking one, often arbitrary, step out of the procedure to quantify roughness.The three methodologies show the same general trend and order of magnitude of roughness (C=30-70 m0.5/s, mean 42 m0.5/s) however kilometer-scale variations show contrasting patterns. Nor dune geometry neither local topographic leeside angle manage to fully explain the variations in the roughness as obtain from the st. Vernant equations. From this we conclude that bed morphology does not seem to be the only explaining factor for roughness variations. Possible explanations include the low leeside angle of dunes (mean

The Weddell Sea is of global importance in the formation of dense bottom waters associated with sea‐ice formation and ocean‐ice sheet interaction occurring on the shelf areas. In this context, the Weddell Sea boundary current system (BCS) presents a major conduit for transporting relatively warm water to the Weddell Sea ice shelves and for exporting {some modified form of Wedell Sea deep and bottom waters into the open ocean. This study investigates the downstream evolution of the structure and the seasonality of the BCS along the Weddell Sea continental slope, combining ocean data collected for the past two decades at three study locations. The interannual‐mean geostrophic flow, which follows planetary potential vorticity contours, shifts from being surface‐intensified to bottom intensified along‐stream. The shift occurs due to the densification of water masses and the decreasing surface stress that occurs westward, towards the Antarctic Peninsula. A coherent along‐slope seasonal acceleration of the barotropic flow exists, with maximum speed in austral autumn and minimum speed in austral summer. The barotropic flow significantly contributes to the seasonal variability in bottom velocity along the tip of the Antarctic Peninsula. Our analysis suggests that the winds on the eastern/north‐eastern side of the gyre determines the seasonal acceleration of the barotropic flow. In turn, they might control the {export} of Weddell Sea Bottom Water on seasonal time‐scales. The processes controlling the baroclinic seasonality of the flow need further investigation. Plain Language Summary In the Weddell Sea, large amounts of seawater are cooled to become dense and sink, carrying signals of human induced changes such as atmospheric carbon into the abyss of the ocean. Understanding the variability of the ocean currents at the Antarctic continental margin is critical because it controls both the export of the dense water formed in these areas and the access of warm water that may melt the Antarctic Ice Sheet. This study investigates the structure and the seasonality of the flow at the continental margin in the Atlantic sector of the Southern Ocean, using in situ observations upstream and downstream of the dense water formation regions. Following the bathymetry, ocean currents flow from East to West along the continental shelf edge. As water densifies along this path, the flow speed changes from being maximum at the ocean surface to be maximum at the bottom. The depth‐averaged current varies with a synchronized seasonality along the continental shelf break, reaching a maximum in austral autumn. Our analysis suggests that the winds on the eastern/north‐eastern margin drives the seasonality of the depth‐averaged flow along the shelf break, significantly contributing to changes in bottom velocity near the export region.

We quantitatively investigated the flow laws of wet quartzite in steady-state dislocation creep regimes by considering both the dependence of the activation enthalpy on pressure and dependence of t...

Mediterranean Outflow Water (MOW) adds salt and density to open ocean intermediate waters and is therefore an important motor of Atlantic meridional overturning circulation (AMOC) and climate variability. However, the variability in strength and depth of MOW on geological timescales is poorly documented. Here we present new detailed records, with excellent age control, of MOW variability from 416 ka to present from rapidly accumulated marine sediments recovered from the West Iberian Margin during Integrated Ocean Drilling Program (IODP) Expedition 339. Our records of x-ray fluorescence (XRF), physical grain size and palaeocurrent information from the anisotropy of magnetic susceptibility (AMS) indicate (i) a close relationship between the orientation of principle AMS axes and glacial-interglacial cycles and (ii) two distinct regimes of MOW behaviour over the last ~416 kyrs in grain size and AMS variability at orbital (mainly precessional) and suborbital timescales. Between marine isotope stages (MIS) 10 and MIS 4, MOW was focused at a generally shallow depth on the West Iberian Margin, and changes in MOW strength were strongly paced by precession. A transition interval occurred during MIS 5 and 4, when MOW deepened and millennial-scale variability in strength flow strength was superimposed on orbitally paced change. During MIS 11 and from MIS 3 to present, MOW was deeply focused and millennial-scale variability dominated. We infer that late Pleistocene variability in MOW strength and depth were strongly climate- influenced and that changes in circum-Mediterranean rainfall climate were likely a primary control.

Vegetation growing in river bars and banks determines the morphological processes in river channels. The presence and dynamics of riverine vegetation depend on the magnitude and frequency of floods able to change morphology and uproot plants, and on the plant's resistance to pull-out. A series of pull-out experiments were carried out with the objective to determine the resistance of riverine vegetation to be uprooted and its effects on river-bed dynamics. Nine riverine species were used for the experiment: seven of them are native from Chile, and the other two are exotic and invasive in Chilean environments. A total of 200 specimens were transplanted in a substrate simulating a bar of a gravel-bed river, and after 7 months they were individually pulled-out, and the force and time needed to uproot the plant quantified. Data were analysed by means of generalised linear models (GLM) and linear regressions, and force-time curves were interpreted and related to the root morphology of the species. GLM results showed that resistance values were dependent on root and plant physical characteristics, and by the factor species. Among the species studied, the three species showing higher resistance values were native, while the less resistant was an exotic invasive species. The time needed to uproot the individuals did not seem to be influenced by plant parameters nor by the factor species. Root architecture seemed to have an effect on plant pull-out resistance and uprooting rapidity, being heart-shaped roots the ones that registered higher resistance values. Despite this, when incorporating flow strength on the findings, the exotic invasive ones seemed to be some of the more resistant to uprooting. The findings of this paper contribute to the better understanding of river vegetational and sedimentary dynamics, and are useful for parameterising the modelling of fluvial landscapes evolution and for the design of river restoration projects.

In situ neutron diffraction measurements were completed during tensile and compressive deformation of stainless steel 304L additively manufactured (AM) using a high power directed energy deposition process. Traditionally produced wrought 304L material was also studied for comparison. The AM material exhibited roughly 200 MPa higher flow stress relative to the wrought material. Crystallite size, crystallographic texture, dislocation density, and lattice strains were all characterized to understand the differences in the macroscopic mechanical behavior. The AM material’s initial dislocation density was about 10 times that of the wrought material, and the flow strength of both materials obeyed the Taylor equation, indicating that the AM material’s increased yield strength was primarily due to greater dislocation density. Also, a ~50 MPa flow strength tension/compression asymmetry was observed in the AM material, and several potential causes were examined.

In the construction process of coastal buildings, how to improve the stability of the soft soil foundation of coastal buildings so as to increase its service life is always a problem that needs to be paid attention to and solved in the construction process. In Qingdao sea beach, for example, according to the force of the foundation, the foundation of the wave force and tidal forces modeling analysis, and puts it into the fluid - sand erosion simulation model, the soft foundation in the best shape of certain external environment, slow down the erosion of various kinds of flow strength of foundation. Finally, we conduct sensitivity analysis and conclude that our model has good stability.

Mill tailings generated from the processing plant have been increasingly used in cemented paste backfill (CPB); however, the effect of their fineness (

Swirling flow at vertical shaft spillways with an innovative geometry, circular piano-key (CPK) inlet, is investigated based on model experimentation. Detailed measurements of head–discharge relationships, threshold submergence, and flow hydraulic characteristics were performed for CPK spillways. Conditions at the beginning of the submergence are analysed, because this situation is related to a condition in which flow instabilities appear on the spillway crest. The results show that the swirling flow strength for flow through the CPK spillway is several times lower than that for simple shaft spillways. This structure yields excellent hydraulic performance, e.g. increasing the weir overflow length by at least 200% without changing the global size of the shaft spillway, thereby increasing the flow discharge up to six times compared with a simple shaft spillway. Finally, two correlations are derived for determining the threshold submergence depth and discharge coefficient of CPK spillways.

The mechanical behavior of nanolaminates is dominated by interfaces that act as sources, barriers, and preferred sites for storage and dynamic recovery of glide dislocations. In this article, the deformation mechanisms of a variety of metal-based nanolaminates are reviewed with emphasis on unusual mechanical properties such as ultra-high flow strength without loss of plastic deformability.

Enhancing nanoscale liquid flows remains an existing challenge in nanofluidics. Here we propose the generation of highly augmented thermoosmotic (TOS) liquid flows in soft nanochannels (or nanochannels functionalized by grafting with end-charged polyelectrolyte or PE brushes) by employing an axial temperature gradient. The TOS transport is a combination of the induced-electric-field electroosmotic (EOS) transport and a thermo-chemioosmotic (TCOS) transport with the latter resulting from an induced pressure gradient on account of the changes associated with the imposition of the axial temperature gradient. The end-charged brushes develop an electric double layer (EDL) localized at the charged, non-grafted brush end. Depending on the system parameters, this EDL localization massively augments the influence of the EOS body force and the induced pressure-gradient resulting in a TOS transport in soft nanochannels that can be more than one order of magnitude larger than that in brush-free nanochannels. Given the existing notion that the presence of the brushes invariably reduces the flow strength, this result of massive flow augmentation is extremely significant and non-trivial serving as a paradigm shift in the study of liquid transport in brush-grafted nanochannels.

International audience; We study experimentally the motion of non-deformable microbeads in a linear shear flow close to a wall bearing a thin and soft polymer layer. Combining microfluidics and 3D optical tracking, we demonstrate that the steady-state bead/surface distance increases with the flow strength. Moreover, such lift is shown to result from flow-induced deformations of the layer, in quantitative agreement with theoretical predictions from elastohydrodynamics. This study thus provides the first experimental evidence of ``soft lubrication'' at play at small scale, in a system relevant {\it e.g.} to the physics of blood microcirculation.

Adhesion of polymers and proteins to substrates plays a crucial role in many technological applications and biological processes. A prominent example is the von Willebrand factor (VWF) protein, which is essential in blood clotting as it mediates adhesion of blood platelets to the site of injury at high shear rates. VWF is activated by flow and is able to bind efficiently to damaged vessel walls even under extreme flow-stress conditions; however, its adhesion is reversible when the flow strength is significantly reduced or the flow is ceased. Motivated by the properties and behavior of VWF in flow, we investigate adhesion of shear-activated polymers to a planar wall in flow and whether the adhesion is reversible under flow stasis. The main ingredients of the polymer model are cohesive inter-monomer interactions, a catch bond with the adhesive surface, and the shear activation/deactivation of polymer adhesion correlated with its stretching in flow. The cohesive interactions within the polymer maintain a globular conformation under low shear stresses and allow polymer stretching if a critical shear rate is exceeded, which is directly associated with its activation for adhesion. Our results show that polymer adhesion at high shear rates is significantly stabilized by catch bonds, while at the same time they also permit polymer dissociation from a surface at low or no flow stresses. In addition, the activation/deactivation mechanism for adhesion plays a crucial role in the reversibility of its adhesion. These observations help us better understand the adhesive behavior of VWF in flow and interpret its adhesion malfunctioning in VWF-related diseases.

The dislocation density of two as-quenched and quenched and tempered low-C Nb–Ti microalloyed martensitic steels was measured with X-ray diffraction for a range of prior austenite grain sizes. The dislocation density decreases with increasing prior austenite grain size in the as-quenched condition but the opposite occurs after high temperature tempering. The flow strength of all conditions is a function of dislocation density and follows a Taylor hardening model. The properties are insensitive to Nb microalloying for the two alloys assessed.

The Nordic Seas overflows are an important part of the Atlantic thermohaline circulation. While there is growing evidence that the overflow of dense water changed on orbital time scales during the Holocene, less is known about the variability on shorter time scales beyond the instrumental record. Here we reconstruct the relative changes in flow strength of Iceland-Scotland Overflow Water (ISOW), the eastern branch of the overflows, on multidecadal-millennial time scales. The reconstruction is based on mean sortable silt ( SS¯) from a sediment core on the Gardar Drift (60°19′N, 23°58′W, 2081 m). Our SS¯ record reveals that the main variance in ISOW vigor occurred on millennial time scales (1–2 kyr) with particularly prominent fluctuations after 8 kyr. Superimposed on the millennial variability, there were multidecadal-centennial flow speed fluctuations during the early Holocene (10–9 kyr) and one prominent minimum at 0.9 kyr. We find a broad agreement between reconstructed ISOW and regional North Atlantic climate, where a strong (weak) ISOW is generally associated with warm (cold) climate. We further identify the possible contribution of anomalous heat and freshwater forcing, respectively, related to reconstructed overflow variability. We infer that ocean poleward heat transport can explain the relationship between regional climate and ISOW during the middle to late Holocene, whereas freshwater input provides a possible explanation for the reduced overflow during early Holocene (8–10 kyr).

The Labrador Current transports freshwater from the Arctic regions to the northern Atlantic and the freshwater flux can influence the meridional overturning circulation. The response of the Labrador Current to meltwater processes is unclear during the deglaciation of the ice sheets around the northwest Atlantic. This study utilized cores from Flemish Pass to monitor variations in the strength of the Labrador Current by using the sortable-silt proxy. The carbonate content, the amount of ice-rafted detritus and XRF chemical data were measured to identify the main meltwater events during the last deglaciation. This study observed a clear enhancement of the flow strength of the Labrador Current in Heinrich Event 1 and the Younger Dryas, with the greatest flow strength during the Younger Dryas event. The onset of the current enhancement was dated at ca 13 cal ka BP, which preceded the enhanced ice-rafted deposition in Hudson Strait by about one thousand years. The current enhancement in Flemish Pass during the Younger Dryas event corresponds to the freshening of the surface water. Thus meltwater preceding significant iceberg supply has an important effect on the Labrador Current in Heinrich events on the Laurentide Ice Sheet margin.

Crack growth rate (CGR) testing in BWR normal water chemistry was performed on compact tension (CT) specimens of two different sizes (B = 8 mm and B = 19 mm), machined from a Type 304 SS core shroud at a dose of ~1 dpa. The objectives were to study the effect of specimen size on the CGR, and to determine the K validity limit for a CT specimen dimension used in previous studies. The results show that for materials with significant strain hardening capacity remaining, there is no effect of specimen size on the CGR when testing is conducted at stress intensity factors valid according to ASTM E399 using the flow strength. For materials at higher dose in which the strain hardening capacity is lost or greatly reduced, a different K validity criterion might be applicable.

This paper is broadly concerned with the dynamics of a polymer confined to a rectangular slit of width D and deformed by a planar elongational flow of strength γ. It is interested, more specifically, in the nature of the coil-stretch transition that such polymers undergo when the flow strength γ is varied, and in the degree to which this transition is affected by the presence of restrictive boundaries. These issues are explored within the framework of a finitely extensible Rouse model that includes pre-averaged surface-mediated hydrodynamic interactions. Calculations of the chain's steady-state fractional extension x using this model suggest that different modes of relaxation (which are characterized by an integer p) exert different levels of control on the coil-stretch transition. In particular, the location of the transition (as identified from the graph of x versus the Weissenberg number Wi, a dimensionless parameter defined by the product of γ and the time constant τp of a relaxation mode p) is found to vary with the choice of τp. In particular, when τ1 is used in the definition of Wi, the x vs. Wi data for different D lie on a single curve, but when τ3 is used instead (with τ3 > τ1) the corresponding data lie on distinct curves. These findings are in close qualitative agreement with a number of experimental results on confinement effects on DNA stretching in electric fields. Similar D-dependent trends are seen in our calculated force vs. Wi data, but force vs. x data are essentially D-independent and lie on a single curve.

The effect of the strength ratio extracted from an Archard model for wear is used to describe the wear rates expected in hot forging dies. In the current study, the strength ratio is the strength of the hot forging die to the strength of the work piece. Three hot forging die steels are evaluated. The three die steels are FX, 2714, and WF. To determine the strength of the forging die, a continuous function has been developed that describes the yield strength of three die steels for temperatures from 600 to 700 °C and for times up to 20 h (i.e., tempering times of up to 20 h). The work piece material is assumed to be AISI 1045. Based on the analysis, the wear resistance of WF should be superior and FX should be slightly better than 2714. Decreasing the forging temperature increases the strength ratio, because the strength of the die surface increases faster than the flow strength of AISI 1045. The increase in the strength ratio indicates a decrease in the expected wear rate.

We report wind-tunnel measurements on aeolian sand transport aiming at characterizing the distribution of the length and height of trajectories of the saltating particles. We employ a simple horizontal sand trap device to assess the distribution of saltation length while the distribution of saltation height is inferred from the measurements of the particle lift-off velocity by means of particle velocimetry tracking techniques. Our measurements reveal that the saltation length and height present a continuum distribution which decreases monotonously and exhibits a long tail that can be well described by a lognormal law. Interestingly, these distributions are found almost invariant with the flow strength. As a consequence, the mean saltation length ( l ¯ ) and height ( h ¯ ) are independent of the flow strength confirming previous indirect measurements. The influence of the flow strength is only seen through the tail of the saltation length distribution: the higher the Shields number, the flatter the distribution tail. Finally, experiments carried out with sand of different sizes show that the mean saltation length and height are not related to the sand grain size through a simple manner but depend instead linearly with the height z f of the Bagnold focus point: l ‾ ≈ 6 z f and h ‾ ≈ 0.6 z f . This last result emphasizes that the focus height is an important characteristic length scale of the saltation transport.

The objective of this study is to reduce V content of Ni-base dual two-phase intermetallic alloy, with keeping the dual two-phase microstructure and also without sacrificing their mechanical and chemical properties. The dual two-phase microstructure was maintained when Cr and Nb instead of V were added to the alloy and their valence electron concentration ( e / a ) ranges from 8.59 to 8.43. Consequently, the contents of V in the dual two-phase intermetallic alloy were reduced by 8 at%, 8 at%, and 3 at% by Cr substitutions for V-site, both of Ni- and V-sites, and Ni-site, respectively. The density of the modified alloys slightly increased from that of the base alloy. Hardness was higher in the modified alloys than in the base alloy. The flow strength of the modified alloys is much improved from that of the base alloy in a wide range of temperatures. Also, oxidation resistance of the modified alloys was superior to those of the base alloy.

Experimental investigation on estimation of fractional critical tractive stress of nonuniform unimodal and bimodal sediment mixtures is reported. The observed data on fractional bed load transport rates for different flow strength, under equilibrium condition, have been used to estimate critical tractive stress (CTS) of each size fraction in sediment mixture from reference transport method (RTM). Further, the accuracy of these estimated CTS values are assessed by comparing the same with CTS values estimated using largest grain method (LGM). The estimated CTS values of individual size fractions for different sediment mixtures have been used to assess the performance of CTS relationship recently proposed by Patel et al. [12] .