Spreading Width Research Articles

Studies on interrelationship and path co-efficient analysis on the basis of fruit yield in eggplant (Solanum melongena L.)

The genotypic and phenotypic correlation and path co-efficient in nineteen genetically diverse genotypes of eggplant were studied at Vegetable Research Station (C S Azad University and Technology, Kanpur) during Kharif season. Studies on relationship at genotypic level revealed positive and strong correlation of yield per plant, number of branches per plant, width of fruit, plant spread and fruit weight in parents, F1s and F2s, whereas significant and positive association of yield per plant with number of fruits per plant were observed in parents, F1s and F2s at phenotypic level. Path coefficient analysis indicate that number of fruits per plant had highest direct/desirable effect on yield per plant followed by fruit weight in both F1 and F2 at genotypic and phenotypic level and days to flowering in F1 and F2 only at genotypic level. The highest positive direct effect on yield per plant was observed by most of the yield contributing characters, i. e., days to marketable maturity and number of branches per plant via number of fruits per plant, length of fruit and width of fruit, and plant spread via number of fruits per plant in F1 and F2 generations at both genotypic and phenotypic levels.

The Influence of Rheological and Wetting Properties of Hydrogel‐based Bio‐Inks on Extrusion‐based Bioprinting

AbstractThe wall slip and flow behavior of alginate as well as gelatin based hydrogels with respect to the impact of these rheological and wetting properties on extrusion‐based bioprinting (EBB) was investigated. Capillary rheometry and printing tests indicate that slip is negligible at high stresses relevant for EBB, i.e., well above the hydrogels yield stress. On the contrary, rotational rheometry performed at low shear stresses revealed that alginate hydrogels present much stronger slip than gelatin gels, irrespective of crosslinker and polymer concentration. This result is presumably due to the formation of a heterogeneous microstructure for alginate gels and has an unfavorable impact on the printing quality with the production of large fluctuations in line width and higher line spread ratio.

Transmission efficiency and beam reception of the SESRI 300 MeV synchrotron injection line

SESRI 300 MeV synchrotron in Harbin Institute of Technology is now under construction and the whole equipment has been installed and tested. Before commissioning beam, the beam transport through the injection line is simulated by using a full-scall model through the Tracewin code. The field distribution of RFQ cavity is calculated with CST, and the results are substituted into the Tracewin code to generate the accurate results. The envelop mode and multi-particles mode are used in the beam simulation with two typical beams (H<inline-formula><tex-math id="Z-20220529151953">\begin{document}${}_2^+ $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20212112_Z-20220529151953.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20212112_Z-20220529151953.png"/></alternatives></inline-formula> and <sup>209</sup>Bi<sup>32+</sup>, the lightest beam and the heaviest beam). Both beams are accelerated from 4 keV/u to 2 MeV/u by an RFQ cavity and two IH-DTL cavities. Then the H<inline-formula><tex-math id="Z-20220529152018">\begin{document}${}_2^+ $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20212112_Z-20220529152018.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20212112_Z-20220529152018.png"/></alternatives></inline-formula> beam is stripped into a proton beam by a carbon foil and accelerated to 5.6 MeV with the third IH-DTL cavity. Simulation results show that the strength of the magnetic field and the acceleration field are proportional to the mass charge ratio. The beam transmission efficiency and the injection line reception are inversely proportional to the beam transverse emittance. The <sup>209</sup>Bi<sup>32+</sup> beam transmission efficiency and beam reception (momentum spread less than ±0.2%) are 72.16% and 46.72% with transverse emittance <i>ε</i> = 0.12π mm·mrad (ECR source output) and <i>ε</i> = 0.4π mm·mrad (RFQ output). H<inline-formula><tex-math id="Z-20220529152204">\begin{document}${}_2^+ $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20212112_Z-20220529152204.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20212112_Z-20220529152204.png"/></alternatives></inline-formula> beam transmission ratio and beam reception are 24.19% and 17.89% with <i>ε</i> = 0.2π mm·mrad (ECR source output) and <i>ε</i> = 0.5π mm·mrad (RFQ output). In order to obtain high transmission efficiency and beam reception, the transverse emittance should be limited to 0.1π mm·mrad after the RFQ. With this limitation, the <sup>209</sup>Bi<sup>32+</sup> beam transmission efficiency and the reception are increased to 96.68% and 92.63%, respectively, and the H<inline-formula><tex-math id="Z-20220529152129">\begin{document}${}_2^+ $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20212112_Z-20220529152129.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20212112_Z-20220529152129.png"/></alternatives></inline-formula> beam transmission efficiency and the rception rise to 74.40% and 68.18%, respectively. If two additional quadrupole magnets are added, the H<inline-formula><tex-math id="Z-20220529152030">\begin{document}${}_2^+ $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20212112_Z-20220529152030.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20212112_Z-20220529152030.png"/></alternatives></inline-formula> beam transmission efficiency and beam reception can be increased to 90.73% and 83.61%, respectively, which will fulfill the requirement for long-time operation. The phase space change process shows that loss of <sup>209</sup>Bi<sup>32+</sup> beam is caused mainly by longitudinal defocusing (energy spread and phase width spread), the loss of proton beam is caused both by the longitudinal defocusing and by the transverse defocusing (beam envelop spreading), that is why two additional focusing magnets should be added in proton beam acceleration. Results also show that by using field distribution calculation in the simulation process the greater influence of the cavity design details can be confirmed such as beam off-axis caused by dipole field in the IH-DTL cavity and beam loss caused by unperfect field in the RFQ. Tracking with field distribution is shown to be a useful method to link the cavity design process, beam line design process, and beam commission process.

Phenotypic diversity and path analysis of seed yield in Bambara groundnut grown in rain forest agroecological zone

Abstract Bambara groundnut is a reliable source of carbohydrates and protein in rainforest agroecology, but limited research had been done and few varieties commercialised. The magnitude of phenotypic variability, character association, and contribution of characters to seed yield were investigated among 50 accessions received from IITA, Nigeria. Field evaluation took place during the 2017 – 18 cropping seasons. The accessions were allocated to experimental plots using a Randomised Complete Block Design with three replicates. Data were collected on phenological, agronomic, and seed yield characters. The main effect showed significant (p ≤ 0.05) differences for phenological, vegetative, and reproductive characters. The year effect influenced agronomic and seed yield characters while accessions by year interaction were insignificant for all characters. The stepwise discriminant analysis identified three redundant characters. The leaflet length and width, canopy spread, leaf/plant, seeds/plant, and seed weight showed high discriminatory ability and are efficient for morphological characterisation and conservation. Hybridisation between accessions dispersed in quadrants 1, 2, and 4 may evolve early and medium maturity types with improved seed yield and biomass. The number of seeds/plant and pods/plant are indices for seed yield. The contribution of pods/plant to seed yield was masked by canopy spread, peduncle length, and pod width indicating competition for photo-assimilates. TVSu 17, TVSu 277, TVSu 271, and TVSu 278 are donor parents for earliness. TVSu 261 performed best for seed yield and yield component characters. Hybridisation among TVSu 261, TVSu 587, TVSu 275, and TVSu 17 will evolve medium maturing and high seed-yielding varieties for further evaluation.

Textures of Non-Oriented Electrical Steel Sheets Produced by Skew Cold Rolling and Annealing

In order to investigate the effect of cold rolling deformation mode and initial texture on the final textures of non-oriented electrical steels, a special rolling technique, i.e., skew rolling, was utilized to cold reduce steels. This not only altered initial textures but also changed the rolling deformation mode from plane-strain compression (2D) to a more complicated 3D mode consisting of thickness reduction, strip elongation, strip width spread and bending. This 3D deformation induced significantly different cold-rolling textures from those observed with conventional rolling, especially for steels containing low (0.88 wt%) and medium (1.83 wt%) amounts of silicon at high skew angles (30° and 45°). The difference in cold-rolling texture was attributed to the change of initial texture and the high shear strain resulting from skew rolling. After annealing, significantly different recrystallization textures also formed, which did not show continuous <110>//RD (rolling direction) and <111>//ND (normal direction) fibers as commonly observed in conventionally rolled and annealed steels. At some skew angles (e.g., 15–30°), the desired <001>//ND texture was largely enhanced, while at other angles (e.g., 45°), this fiber was essentially unchanged. The formation mechanisms of the cold rolling and recrystallization textures were qualitatively discussed.

Breeding potential of acrid elephant foot yam genotypes for yield and nutritional quality using multivariate analysis

Acrid genotypes (var. sylvestris) of elephant foot yam [Amorphophallus paeoniifolius (Dennst.) Nicolson syn. A. campanulatus (Roxb.) BL. Ex Dence] are consumed in spite of non-acrid (var. hortensis) types being available, due to their specific flavor, color and taste. Acrid genotypes need to be evaluated for yield and nutrition related characters for selection of desirable food and nutrition content. Genotypes variability was evaluated for yield related traits. Pseudo-stem diameter, number of leaflets, corm volume and corm yield per plant had high genotypic coefficient of variation, heritability and genetic advance as per cent of mean indicating selection would bring improvement in these traits. The top priority should be given to selection based on corm volume, canopy spread and corm width for yield improvement and could be considered while formulating selection indices in the improvement of elephant foot yam. Principal components of most variable traits, pseudo-stem diameter, canopy spread, number of leaflets, corm length, corm width, corm volume and corm yield per plant had eigen values >1 and accounting for 92.82 % of total variation among eleven genotypes. The cophenetic correlation coefficient of dendrogram (0.733) was very close to 1, indicating clustering was good. Based on average performance, genotypes ACC-85 and ACC-136 were found promising for corm yield and carbohydrate, potassium, iron, and zinc contents. The outcome of the study will be helpful for breeders in selection of such genotypes for development of nutritionally rich and high yielding varieties.

Stars Crushed by Black Holes. I. On the Energy Distribution of Stellar Debris in Tidal Disruption Events

Abstract The distribution of orbital energies imparted into stellar debris following the close encounter of a star with a supermassive black hole is the principal factor in determining the rate of return of debris to the black hole, and thus in determining the properties of the resulting lightcurves from such events. We present simulations of tidal disruption events for a range of β ≡ r t/r p where r p is the pericenter distance and r t the tidal radius. We perform these simulations at different spatial resolutions to determine the numerical convergence of our models. We compare simulations in which the heating due to shocks is included or excluded from the dynamics. For β ≲ 8, the simulation results are well-converged at sufficiently moderate-to-high spatial resolution, while for β ≳ 8, the breadth of the energy distribution can be grossly exaggerated by insufficient spatial resolution. We find that shock heating plays a non-negligible role only for β ≳ 4, and that typically the effect of shock heating is mild. We show that self-gravity can modify the energy distribution over time after the debris has receded to large distances for all β. Primarily, our results show that across a range of impact parameters, while the shape of the energy distribution varies with β, the width of the energy spread imparted to the bulk of the debris is closely matched to the canonical spread, Δ E = GM • R ⋆ / r t 2 , for the range of β we have simulated.

Motion of Liquid Convective Flow and Heat Transfer Analysis of Flame Spread over butanol fuel within narrow channels

In actual fire, a solid wall is commonly established using nearby noncombustible solid materials to resist flame propagation. However, there are always some narrow channels owing to uneven surface of solid materials. There are inherent differences between liquid flame spread in narrow channels and infinite width fuel, including dynamic shear and heat dissipation. The experiments of flame spread over n-butanol fuel in narrow channels with lengths of 30, 50, 100, 200 and 300 mm and widths of 3, 4, 5, 6, 7, 8, 9 and 10 mm are carried out. The flame spread is divided into initial stage, restriction stage and jet flow stage. The velocity of subsurface flow decreases strongly once the convective flow enters narrow channel. Based on the assumption that surface tension is balanced with sum of viscous force and shear force, the velocity of subsurface flow at restriction stage is calculated which overestimates ∼10% of measurement. The flame cannot pass through the channel when heat loss accounts for more than 43% of total heat flux of subsurface flow. The heat absorption by sidewalls always accounts for more than 80% of total heat loss. The current finding provides a theoretical guidance for actual liquid firefighting.

Hybrid model for the damped transient response of giant dipole resonances

We suggest the hybrid model for the description of the dipole spreading widths, in which the strength function is built on the one-phonon strength distribution folded with the energy-dependent Lorentzian. Its energy dependence is brought about by (i) the energy-dependent smearing parameter and (ii) the energy-dependent shift of the one-phonon states. These variables are estimated by means of the two-phonon density, provided by a modified Fermi gas model with uniformly spaced states, and with the aid of the weak constant interaction between the one-phonon states and the two-phonon states, considered as background states. Based on calculated one-phonon states, the model is analytically solvable. To explore the validity of the model we analyze the properties of the ${1}^{\ensuremath{-}}$ spectrum in $^{206}\mathrm{Hg}$, $^{206}\mathrm{Pb}$, and $^{210}\mathrm{Po}$ nuclei. Our results demonstrate that the description of the decay widths within the latter approach is in good agreement with that obtained in the quasiparticle random phase approximation, by means of the random distribution of the coupling between microscopic one-phonon states and two-phonon states, generated by the Gaussian orthogonal ensemble distribution.

Treatment of patients with complicated fractures of the distal humerus using the fixators of limited-contact multiplanar osteosynthesis

Treatment of distal humerus fractures is a complex problem in traumatology. The result of treatment depends on the choice of fixator according to the fracture area. Objective. To improve the techno­logy of treatment in patients with complicated distal humerus fractures with fixators of small contact and multiplanar osteosynthesis and to evaluate its efficacy. Methods. 39 patients were treated for the period 2000–2020 with distal humerus nonunion (types 12-B1, 12-C1, 12-C2) and 23 patients with complicated above- and transcondylar humerus fractures (types 13-A2, 13-C1, 13-C2). Fixation of bone fragments of the distal humerus was made with device for fixation (Patent 17502 UA). It is a shaped plate with a groove on which half rings with threaded holes are stabilized. For the osteosynthesis of above- and transcondylar humerus fractures we used V-shaped plate with the possibility to regulate branch spreading width as for the condylar size (Patent 33358 UA). Autografting was performed as for necessity. Results. Plate osteosynthesis was performed mainly through anterior approach with minimal tissues traumatization. Release of radial nerve we made as for necessity. This device provides the stable fixation even in a case of short distal fragment. Device for bone fragments fixation was placed on the posterior condylar surface and lower part of the humerus through olecranon osteotomy. Osteosynthesis with suggested device is one of the options with bone autografting and can be method of choice at repeated surgery. Follow-up period was 1–2 years and later. In 60 patients we obtained good results with completed bone union. Conclusions. Suggested device can be used in cases of distal humerus nonunion. It allows to decrease the damage of surgery, to avoid many complications. Key words. Complicated fractures of the distal humerus, devices for limited-contact multiplanar osteosynthesis.

Sea surface temperature predictability in the North Pacific from multi-model seasonal forecast

Sea surface temperature (SST) prediction based on the multi-model seasonal forecast with numerous ensemble members have more useful skills to estimate the possibility of climate events than individual models. Hence, we assessed SST predictability in the North Pacific (NP) from multi-model seasonal forecasts. We used 23 years of hindcast data from three seasonal forecasting systems in the Copernicus Climate Change Service to estimate the prediction skill based on temporal correlation. We evaluated the predictability of the SST from the ensemble members' width spread, and co-variability between the ensemble mean and observation. Our analysis revealed that areas with low prediction skills were related to either the large spread of ensemble members or the ensemble members not capturing the observation within their spread. The large spread of ensemble members reflected the high forecast uncertainty, as exemplified in the Kuroshio–Oyashio Extension region in July. The ensemble members not capturing the observation indicates the model bias; thus, there is room for improvements in model prediction. On the other hand, the high prediction skills of the multi-model were related to the small spread of ensemble members that captures the observation, as in the central NP in January. Such high predictability is linked to El Niño Southern Oscillation (ENSO) via teleconnection.

Influence of Roll Diameter on Material Deformation and Properties during Wire Flat Rolling

The influence of roll diameter on the strain distribution, shape change, contact pressure, and damage value of a workpiece was investigated during wire flat rolling to control the material properties of the flattened wire. The flattened wires fabricated by the four different rolls were compared using finite element analysis. The strain inhomogeneity of the flat-rolled wire increased with the roll diameter; thus, the macroscopic shear bands were strengthened as the roll diameter increased during wire flat rolling. The contact width and lateral spreading of the flattened wire increased with the roll diameter; therefore, the reduction in area decreased with the roll diameter. The contour of the normal contact pressure on the wire surface exhibited a similar pattern regardless of the roll diameter. The contact pressure showed higher values at the entry, edge, and exit zones in the contact area. The distribution of the damage value varied with the roll diameter. The free surface region tended to have the peak damage value during the process; however, the center region exhibited the maximum damage value with the roll diameter. From the perspective of the damage value, the optimum roll diameter was in existence during wire flat rolling. The underlying cause of the different strain distributions, shape changes, and damage values of the flat-rolled wire was the different contact lengths originating from the different roll diameters during wire flat rolling.

Numerical verification on influence of multi-feature parameters to the downwash airflow field and operation effect of a six-rotor agricultural UAV in flight

The airflow field produced by UAV is an important factor to determine the movement of spray droplets, which can enhance deposition and reduce drift. Therefore, in this study, the downwash airflow field of the six-rotor plant protection UAV in the flight state was simulated based on the Lattice Boltzmann method (LBM), and the distribution characteristics at multi-feature parameters including different flight speed, flight height, crosswind speed and work load were studied. In addition, take the coverage area and the penetrable area as evaluating index, the influence of multi-feature parameters and prediction model to the operation effect were investigated. The results showed that, with the increase of flight speed and height, the angle of backward tilt of the downwash airflow field gradually increased, and the length and width of longitudinal and horizontal spread on the ground decreased. The optimal flight speed and height for UAV operations respectively were 2 m or 2.5 m, and 4 m/s based on the evaluating index. As the flight height increased from 2 m to 3 m, the eddies became larger, and they would entrain and affect the spatial movement and distribution of droplets. Furthermore, the distribution of the airflow structure was obviously changed with the increase of crosswind speed, and the coverage area and the penetrable area had a huge decline when the crosswind speed was greater than 3 m/s, which was not fit for operations. By the designed orthogonal test, the prediction models of the coverage area and the penetrable area were established, the R square was 0.952 and 0.759, respectively; the influence of multi-parameters to the operation effect was analyzed, and the prediction of the models for the dependent variables were relatively accurate. The results of the study could provide reference for exploring the downwash airflow field and droplet deposition pattern in the complex airflow field when UAV sprayings.

Modulating flow and mixing characteristics of an inclined jet in crossflow at a large backward inclination angle by acoustic excitation

Previous investigations revealed that the backward-inclined jet in crossflow exhibits seemingly lower transverse velocity and turbulence intensity at inclination angles higher than a critical value about 25°, thus resulting in significantly low jet fluid dispersion properties. In this article, the acoustic excitations were applied to a backward-inclined jet in crossflow at an inclination angle higher than the critical value to examine experimentally whether the flow and dispersion characteristics could be improved or not. The flow in the test section of an open-loop wind tunnel was used as the crossflow. A profiled nozzle assembly with a loudspeaker installed in the lower part of it was used to generate the pulsating jet. The instantaneous and time-averaged smoke flow patterns were obtained by the laser-light-sheet assisted flow visualization method. The binary edge detection method was employed to the long-exposure smoke flow images to measure the jet spread width. The turbulence intensities, as well as the Lagrangian integral turbulence time and length scales, were obtained using a hotwire anemometer. The jet-fluid dispersion characteristics were examined using the tracer-gas detection technique. The results revealed that in the domain of jet pulsation intensity and excitation Strouhal number, the pulsed backward-inclined jet in crossflow presented three characteristic flow modes: synchronized oscillating jet, transition, and synchronized shear-layer vortices. The synchronized oscillating jet exhibited violent transverse oscillations due to the high axial jet pulsations induced by the acoustic excitation. The transverse jet width and jet penetration height were enlarged. The turbulence intensities were significantly increased, and the turbulence time and length scales were decreased, therefore led to a significant enhancement in the jet-fluid dispersions and mixing capabilities.

A Wave Prediction Framework Based on Machine Learning and the Third Generation Wave Model

Abstract To predict the evolution of wave spectrum in the real ocean, a machine learning framework is developed by training a long short-term memory (LSTM) neural network on a physics-based third-generation wave model (Simulating WAve Nearshore (SWAN)). Considering the realistic ocean waves are usually mixtures of windsea and swells, the wave spectrum is partitioned using a watershed algorithm, such that the windsea and swells are analyzed and predicted separately. Four parameters are selected to capture the wave spectrum of each system, including the significant wave height Hs, peaked wave period Tp, mean propagation direction θm, and directional spreading width σθ. The results demonstrate that the LSTM neural network can achieve accurate prediction of wave condition, the mean absolute error percentage (MAEPs) of 1-h prediction is less than 5.9%, 3.3%, 3.5%, and 3.3% for Hs, Tp, θm, and σθ, respectively, and accurate prediction of wave spectra is achieved. Even for the 10-h prediction, satisfactory results are obtained, e.g., the MAEP of Hs is less than 15.5%. The effects of output size (i.e., prediction duration), input data size (i.e., number of delays), as well as different combinations of input features on predictions of wave conditions are examined.

Effects of backward inclination on a pulsed jet in crossflow

The effects of the backward inclination angle on the flow and jet dispersion characteristics of a pulsed jet in crossflow were studied experimentally in an open-loop wind tunnel. The pulsations were created by a loudspeaker which installed at the bottom of a nozzle assembly. The instantaneous and time-averaged flow patterns were obtained using the laser-light sheet assisted smoke flow visualization method. The instantaneous and average velocities, turbulence intensities, integral turbulence time scales were probed using a hot-wire anemometer. The tracer-gas detection technique was applied to examine the fluid dispersion capability of the jet. With excitation, the axial jet pulsations were transferred to transverse oscillations after the jet was deflected by the crossflow. A small jet backward inclination angle could lead to an increase of jet-fluid dispersion and transverse jet spreading width. There existed a critical jet backward inclination angle of 20° at which the jet-fluid dispersion index and transverse jet spreading width attained the maximum values. Arranging the jet backward inclination angle at values smaller than 20° could induce an increase in dispersion of the pulsed jet in crossflow and benefit the industrial applications which required fast and efficient jet-fluid dispersion and mixing. • Jet backward inclination angle presented significant effects on axial mean velocities, turbulence intensities, and dispersion properties. • There existed a critical jet backward inclination angle of 20° at which the jet spreading width and dispersion attain maximum values. • At jet backward inclination angle smaller than critical value, increasing inclination angle could increase jet-fluid dispersion. • At jet backward inclination angle larger than critical value, increasing inclination angle would significantly decrease jet-fluid dispersion. • Arranging jet backward inclination angle at critical value could benefit industrial applications.

Effect of initial conditions on mean flow characteristics of a three dimensional turbulent wall jet

The effect of initial conditions in a [Formula: see text] sidewall enclosure on the mean flow characteristics of a three dimensional turbulent square wall jet has been studied experimentally. The initial conditions are varied by varying the length of the nozzle; it is varied as l/ h = 10, 50, and 90, where l and h indicates the nozzle length and the side of the square nozzle, respectively. The effect of nozzle length on initial velocity profiles, velocity distribution in lateral and wall normal directions, spread rate, decay of maximum mean velocity, local Reynolds number and similarity behaviour has been studied. The wall normal spread width is higher for the nozzle length l/h = 10 in the near field [Formula: see text] but this trend completely changed after [Formula: see text]. The spread rate is found independent of the initial condition of the nozzles in the fully developed region. The decay rate of maximum mean velocity is found higher for l/ h = 10 in the region of ([Formula: see text], whereas decay rate becomes independent of the initial conditions in the fully developed region [Formula: see text]. The local Reynolds number variation is also estimated along the downstream directions for present case and found that the local Reynolds number [Formula: see text] reaches approximately 56% of the jet exit Reynolds number [Formula: see text] at [Formula: see text] for nozzle length l/ h = 10, while it is 57% and 59% of Rejet for the nozzles [Formula: see text] and [Formula: see text] respectively at the same location. The nozzle l/ h = 10 attained self similar behaviour more quickly as compared to the other nozzles. The sidewall played a significant role which pushed the fluid more towards the center resulting in a lower jet half width in the wall normal direction as compared to the corresponding case, without a sidewall. The decay rates of the maximum mean velocity for all the nozzles are estimated to be 1.08 which is in the accepted range found in the literature.

High Mass Resolution Multireflection Time-of-Flight Secondary Ion Mass Spectrometer.

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is popular because of its advantages of parallel m/z detection and less damage for unknown or rare samples compared to sector field instruments. However, the mass resolving power of conventional TOF-SIMS is limited by its relatively large energy spread and primary ion pulse width. In this work, a high mass resolution multireflection time-of-flight secondary ion mass spectrometer (MR-TOF-SIMS) was designed and constructed. Compared with conventional TOF-SIMS, the ion flight path of the MR-TOF-SIMS was extended from meters to subkilometers, and the mass resolving power reached to 87000 after an 80 cycles flight. A pair of symmetrically arranged ion orthogonal injection/ejection deflectors, which could eliminate the influence of fringing field and remove ions with a large energy spread, were proposed to further improve the mass resolving power in fewer flight cycles. A zircon standard sample sputtered by a 10 keV O2- beam was used to demonstrate the performance of the MR-TOF-SIMS instrument. As a result, the mass resolving power was up to 30000 only after 22 flight cycles. The 92Zr+ peak was significantly separated from the mass interference peaks of 91ZrH+, 90ZrH2+, 13CC6H7+, and C7H8+. The mass accuracies of Zr ions and their hydrides were better than 1.2 ppm. An ion transmission efficiency over 40% was achieved after 115 cycles.

Droplet collision and jet evolution hydrodynamics in wetting modulated valley configurations

Droplet impact hydrodynamics on “V”-shaped valleys or grooves of variant wettability and geometric dimensions have been studied experimentally and probed theoretically. The groove geometry makes the hydrodynamics three-dimensional, as in addition to the droplet dynamics in the lateral direction, liquid jets are generated from the post-impact droplet along the axial direction of the groove. The effect of the impact Weber number (We) on the jet velocity, the non-dimensional spreading width (γ), and north-pole height (h*) has been studied. It has been observed that the inertial forces dominate over the surface forces for higher impact We and hence, the effect of wettability is not important. However, the wettability of the substrate has a significant role in lower impact We as recoiling of the droplet is observed for the impact on the superhydrophobic substrate in this case. It has been observed that the spreading width of the post-impact droplet decreases with the increase in groove steepness. The jetting hydrodynamics has been probed and instantaneously after the impact, the generated jets travel at high velocity, but quickly reduce to a steady value. Jet velocity is observed to increase with an increase in the hydrophobicity of the substrate as well as the impact We. A semi-analytical formalism has been proposed to predict the jet velocity evolution in terms of governing Weber (We) and capillary (Ca) numbers. The predictions from the proposed model are in good agreement with the experimental results.

Influence of Volatiles on Mass Wasting Processes on Vesta and Ceres

AbstractWe have analyzed mass wasting features, their distribution and deposit geometry on the two largest main asteroid belt objects—protoplanet Vesta and dwarf planet Ceres—and compared their geomorphology and mobility. Both asteroids have similar surface accelerations, but different surface compositions. Based on our observations and previous studies, we categorized three distinct morphological mass wasting classes: slumps, slides, and flow‐like movements. We conclude that Ceres has abundant features of flow‐like mass movements. Further, sliding and flow‐like characteristics are identified in craters within mid‐latitudes which supports the possibility of the presence of water ice in the near subsurface of Ceres. Vesta predominantly shows characteristics of dry granular‐like slide features which are distributed homogenously across the surface. By plotting the ratio between fall height (H) and run‐out length (L) (effective coefficient of friction, H/L) against the run‐out length and spreading width (W), we demonstrate that deposits on Vesta terminate on shorter distances, whereas on Ceres they travel longer distances. The deposit geometry and the similar surface gravity on both asteroids suggest that the material composition and volatile component have a significant effect on deposit emplacement. However, both bodies’ mass movements have similar effective coefficients of friction, even though Vesta's regolith is comparatively dry, whereas Ceres is rich in water ice. This leads to the conclusion that volatile content alone cannot be responsible for low effective coefficients of friction, and that more than one geological process is needed to explain the mass motion behavior and morphology.