Transition Length Research Articles

Lattice Monte Carlo study of orientational order in a confined system of biaxial particles: Effect of an external electric field.

In this work we have used lattice Monte Carlo to determine the orientational order of a system of biaxial particles confined between two walls inducing perfect order and subjected to an electric field perpendicular to the walls. The particles are set to interact with their nearest neighbors through a biaxial version of the Lebwohl-Lasher potential. A particular set of values for the molecular reduced polarizabilities defining the potential used was considered; the Metropolis sampling algorithm was used in the Monte Carlo simulations. The relevant order parameters were determined in the middle plane of the sample and for some cases across the whole thickness of the sample. We have determined the temperature-electric field phase diagram for this system and found, as expected, five different system configurations corresponding to three different mesophases. At low temperatures and low fields the system finds itself in an undistorted biaxial phase. On increasing the field at low temperatures, a Freedericksz transition takes place and the secondary directors reorient towards the field while the primary director stays undistorted and parallel to the walls. On increasing the field further, a second Freedericksz transition occurs and the primary director orients also towards the field direction. The orientational order measured at the field strengths tested is not affected by the field. On increasing the temperature, a transition to a uniaxial phase occurs and within the range of this phase a field increase leads also to a Freedericksz transition where the main director reorients towards the field. At higher temperature a transition to a disordered phase is found. We have performed finite size scaling analysis for the Freedericksz critical fields and found that they scale with the distance L between the walls as L^{-1} as expected from continuum theory. From these fields we have also determined the temperature dependence of two elastic constant ratios. Critical exponents and critical temperatures for the order parameter and the correlation length for the biaxial-uniaxial phase transition and the uniaxial to disordered phase transition were also determined by finite size scaling and are discussed.

Deformation and cyclic buckling capacity of external replaceable hysteretic dampers for unbonded post-tensioned precast concrete walls

This paper proposes and validates a type of external replaceable hysteretic dampers to be mainly applied to unbonded post-tensioned (UPT) precast walls. The main aim of the proposed damper was to provide the UPT walls with large energy dissipation without significant buckling. To evaluate the efficiency of these dampers, a cyclic test was conducted. The damper specimens consisted of a mild steel round bar with a reduced diameter over a fused length and an additional threaded length at each side, for installation purposes. Moreover, a round steel tube was installed over the fused length and filled with grout to delay the buckling. The proposed dampers, with different geometries and conditions, were subjected to cyclic loads to evaluate their deformation capacity and fracture mechanism. The specimens displayed a regular and stable hysteretic curve until strains of 9%, after which a flexural buckling was observed at the ends of the fused length. However, this flexural buckling did not affect the energy-dissipating capacity in any specimen. Consequently, this type of damper is considered suitable for applications in self-centering rocking walls. Furthermore, the proposed dampers fractured by a combination of low-cycle fatigue and excessive rotations at the transition length. In addition to the experimental validation, an extensive numerical investigation was conducted on the proposed damper to complement the experimental data and to provide analytical tools for design.

Analysis of serpentine coil with alternating flattened axis: An insight into performance enhancement of solar ponds

The fluid flow inside a curved tube is an effective technique to extract the heat restored in the solar ponds. This study aims to analyze the performance of the serpentine coils with alternating flattened axis. Thus, the desired models are fabricated and tested using an experimental setup that simulates the solar pond conations. Numerical simulations are also carried out at the same conditions because the possible mechanisms can be attributed to the synergy between velocity vectors and temperature isotherms. It is found that the maximum deviations between the experimental data and the numerical results are less than ±10%. The results show that the heat extraction enhances with decreasing the segment length (a) and transition length (b) but increasing the flattened depth (c). At the studied ranges, the enhancements are between 1.5% and 88.2%. Accordingly, the penalty in pumping power is between 19.9% and 665.9% depending on geometric parameters. The best models are introduced according to the adopted overall performance index, which has an increasing trend with the mass flow rate. The maximum performance index of 1.32 is recorded for an enhanced model with a = 10 mm, b = 5 mm, and c = 2 mm at the mass flow rate of 0.011136 kg/s.

Antioxidant activity and laxative effects of tannin-enriched extract of Ecklonia cava in loperamide-induced constipation of SD rats.

To investigate the role of tannin-enriched extracts of Ecklonia cava (TEE) on the regulation of oxidative balance and laxative activity in chronic constipation, we investigated alterations after exposure to TEE, on constipation phenotypes, muscarinic cholinergic regulation, and oxidative stress responses in the transverse colons of SD rats with loperamide (Lop)-induced constipation. This extract contains high levels of total condensed tannin content (326.5 mg/g), and exhibited high inhibitory activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. TEE treatment induced significant improvements in reactive oxygen species (ROS) production, superoxide dismutase (SOD) expression and nuclear factor erythroid 2-related factor 2 (Nrf2) phosphorylation in primary smooth muscles of rat intestine cells (pRISMCs) and transverse colon of constipation model. Also, Lop+TEE treated groups showed alleviated outcomes for the following: most stool parameters, gastrointestinal transit, and intestine length were remarkably recovered; a similar recovery pattern was observed in the histopathological structure, mucin secretion, water channel expression and gastrointestinal hormones secretion in the transverse colon; expressions of muscarinic acetylcholine receptors M2/M3 (mAChR M2/M3) and their mediators on muscarinic cholinergic regulation were significantly recovered. Taken together, these results provide the first evidence that TEE stimulates oxidative stress modulation and muscarinic cholinergic regulation when exerting its laxative effects in chronic constipation models.

A newly developed corner smoothing methodology based on clothoid splines for high speed machine tools

Continuous linear commands are widely executed in computer numerical control (CNC) machining. The tangential discontinuity at the junction of consecutive segments restricts the machining efficiency and deteriorates the surface quality. Corners of linear segments have been successfully blended by inserting parametric splines. There still exists challenges when the common methods are employed in the line-segment commands due to part of the following restrictions: (1) the stringent computation for iteratively calculating the arc-length; (2) the unwanted feedrate fluctuation; (3) the oversize contour deviation for separately completing curve fitting and velocity planning. A novel smoothing method based on a clothoid pair to synchronously accomplish planning of geometry blending and speed scheduling is proposed, the spline parameter of which is arc-length-parameterized. The arc-length, curvature extreme, and geometric shape of the transition curve are analytically expressed by the transition length. On these bases, the transition curve and the velocity profile are concurrently constructed based on the predefined approximation error, the reachable velocity, and normal kinematic constraints in the look-ahead stage. Then, a real-time interpolation scheduling is developed to overcome the crossing difficulties between the linear and parametric segments. Compared with existing methods, the proposed method can analytically calculate the length of transition curves for the arc-length-parameterized expression form. Furthermore, the feedrate fluctuation is eliminated in the fine interpolation. Moreover, the overlarge contour derivation produced by corner smoothing is significantly avoided. It is friendlier to the CNC system for the on-line executing smooth motion since more computing resources can be released to handle other tasks, smoother motion can be achieved and higher contour accuracy can be obtained. The experimental results also demonstrate its practicability and reliability.

Liquid-Liquid Phase Separation of Repeat Disorder Sequences Leads to RNA Conformational and Dynamical Heterogeneity

It is increasingly clear that liquid-liquid phase separation plays important functional roles in regulation and maintenance of cellular activity. However, understanding of the complex interplay between the molecular driving forces and the emergent features of the biomolecular condensates such as morphology and material properties is lacking. We develop a coarse-grained model to investigate the phase separation of trinucleotide repeat RNAs, which are implicated in neurological disorders such as Huntington disease and amyotrophic lateral sclerosis. Our simulations reproduce key experimental findings about length and concentration dependence of the phase transition of (CAG)n repeats. We show that once recruited inside the liquid droplets, RNAs undergo significant conformational changes to accommodate the intricate intermolecular interaction network in the condensate. This network, in turn, severely restrains the fluctuation and mobility of the RNA molecules inside large droplets despite the overall fluidity of the systems at long time scale. In the largest droplets where RNAs are densely packed, the movement of RNAs could be characterized by reptation dynamics because the system is highly entangled. Our work provides important microscopic details about the driving forces and mechanism of RNA repeat liquid-liquid phase separation, which currently are not easily accessible in experiments.

Are consumer confidence and asset value expectations positively associated with length of daylight?: An exploration of psychological mediators between length of daylight and seasonal asset price transitions.

Many economists claim that asset price transitions, particularly stock price transitions, have a seasonal cycle affected by length of daylight. Although they claim that the seasonal affective disorder (SAD) is a mediator between the length of daylight and asset price transitions, recent studies in psychology have been inconclusive about the existence of SAD, and some economics studies disagree regarding the involvement of SAD in seasonal stock price transitions. The purpose of the present study is to examine if there is any psychological mediator linking length of daylight and seasonal asset price transitions as an alternative or supplement to SAD. As a possible mediator, we examined Japan's consumer confidence index (CCI) and asset value expectations (AVE), which indicate people's optimism for future economy and are generated from a monthly household survey by the Japanese government. We analyzed individual longitudinal data from this survey between 2004 and 2018 and estimated four fixed-effects regression models to control for time-invariant unobserved heterogeneity across individual households. The results revealed that, (i) there was a seasonal cycle of CCI and AVE; the trough occurred in December and the peak in early summer; (ii) the length of daylight time was positively associated with CCI and AVE; and (iii) the higher the latitude, the larger the seasonal cycle of CCI and AVE became. These findings suggest that the length of the daylight may affect asset price transitions through the cycle of optimism/pessimism for future economy exemplified by the CCI and AVE.

HIFiRE-5b Boundary-Layer Transition Length and Turbulent Overshoot

Hypersonic International Flight Research Experimentation 5 (HIFiRE-5) is a hypersonic flight-test experiment designed to investigate the aerothermodynamics of a 3-D geometry. The vehicle is an elliptic cone with a 2:1 aspect ratio and 2.5 mm nose radius. The HIFiRE-5b achieved a Mach number of 7.7–7.9 and freestream unit Reynolds number of to during descent. Heat flux was calculated from thermocouple pairs and boundary-layer transition locations were identified from these heating rates. A multilobed transition front was observed; it is suspected that a different mechanism is responsible for each of these lobes. The vehicle’s attitude oscillated, which has been exploited to assess the sensitivity of heat flux to yaw angle along the leading edges and ascertain the appropriateness of the filtering applied to the thermocouple signals. Spatial heat-flux profiles have been constructed for constant freestream unit Reynolds numbers. The heat-flux rate at the end of transition is examined; turbulent overshoot was present along some azimuths, but not others. This flight-test result indicates the phenomenon is not specific to ground test, freestream noise level, or wall-to-stagnation-temperature ratio. Finally, transition length (its end location normalized by its onset location) is reported and connected to turbulent spot generation rates.

Flexible human motion transition via hybrid deep neural network and quadruple-like structure learning

Skeletal motion transition is of crucial importance to the animation creation. In this paper, we propose a hybrid deep learning framework that allows for efficient human motion transition. First, we integrate a convolutional restricted Boltzmann machine with deep belief network to extract the spatio-temporal features of each motion style, featuring on appropriate detection of transition points. Then, a quadruples-like data structure is exploited for motion graph building, motion splitting and indexing. Accordingly, the similar frames fulfilling the transition segments can be efficiently retrieved. Meanwhile, the transition length is reasonably computed according to the average speed of the motion joints. As a result, different kinds of diverse motions can be well transited with satisfactory performance. The experimental results show that the proposed transition approach brings substantial improvements over the state-of-the-art methods.

Atomically thin heterostructure with gap-mode plasmon for overcoming trade-off between photoresponsivity and response time

Two-dimensional (2D) materials have recently provided a new perspective on optoelectronics because of their unique layered structure and excellent physical properties. However, their potential use as optoelectric devices has been limited by the trade-off between photoresponsivity and response time. Here, based on a vertically stacked atomically thin p-n junction, we propose a gap-mode plasmon structure that simultaneously enables enhanced responsivity and rapid photodetection. The atomically thin 2D materials act as a spacer for enhancing the gap-mode plasmons, and their short transit length in the vertical direction allows fast photocarrier transport. We demonstrate a high responsivity of up to 8.67 A/W with a high operation speed that exceeds 35 MHz under a 30 nW laser power. Spectral photocurrent, absorption, and a numerical simulation are used to verify the effectiveness of the gap-mode plasmons in the device. We believe that the design strategy proposed in this study can pave the way for a platform to overcome the trade-off between responsivity and response time.

Size-effect method to determine mode-I fracture toughness of aluminium alloys

Size-effect method is used to determine the fracture properties of three aluminium alloys. Mode-I tensile testing of thin rectangular sheets of aluminium alloys 5052−H32, 6061−T6 and 8011 is carried out. The test specimens are scaled geometrically in the ratio of 1:2:3:4 for a constant length (L) to width (D) ratio (L∕D=4). The notch depth (a) to width (D) ratio is 0.25. Size-dependency of strength is observed. The fracture toughness values and the crack growth resistance curves (R-curves) for these three alloys are determined using equivalent elastic crack model. The R-curves predict the peak loads accurately with only 0%–7% difference from the experimental values. The pre-peak load–deflection curves calculated from the R-curves closely match the experimental curves. Bažant’s size effect law could be used to fit the peak load data. Scaling laws for strains at peak loads are proposed. The transition length (D0) determined for these strain scaling laws differ from those obtained using the size effect law.

Deficiency of complement component 3 may be linked to the development of constipation in FVB/N‐C3em1Hlee/Korl mice

Alterations in complement component 3 (C3) expression has been reported to be linked to several bowel diseases including Crohn's disease, inflammatory bowel disease, and ulcerative colitis; however, the association with constipation has never been investigated. In this study, we aimed to investigate the correlation between C3 regulation and constipation development using a C3 deficiency model. To achieve these, alterations in stool excretion, transverse colon histological structure, and mucin secretion were analyzed in FVB/N-C3em1Hlee /Korl (C3 knockout, C3 KO) mice with the deletion of 11 nucleotides in exon 2 of the C3 gene. The stool excretion parameters, gastrointestinal transit, and intestine length were remarkably decreased in C3 KO mice compared with wild-type (WT) mice, although there was no specific change in feeding behavior. Furthermore, C3 KO mice showed a decrease in mucosal and muscle layer thickness, alterations in crypt structure, irregular distribution of goblet cells, and an increase of mucin droplets in the transverse colon. Mucin secretion was suppressed, and they accumulated in the crypts of C3 KO mice. In addition, the constipation phenotypes detected during C3 deficiency were confirmed in FVB/N mice treated with C3 convertase inhibitor (rosmarinic acid (RA)). Similar phenotypes were observed with respect to stool excretion parameters, gastrointestinal transit, intestine length, alterations in crypt structure, and mucin secretion in RA-treated FVB/N mice. Therefore, the results of the present study provide the first scientific evidence that C3 deficiency may play an important role in the development of constipation phenotypes in C3 KO mice.

Using Wearable Sensors to Remotely Evaluate Progress on Goals Set by Patients With Dementia

Patient Priorities Care (PPC) is a communication framework designed to facilitate priorities-based conversations between clinicians and older adults with multiple chronic conditions. PPC focuses on collaboratively setting specific and measurable goals based on what matters most, and patients often set goals involving physical activity. Measuring goal achievement for patients with dementia is difficult because they often struggle to report activity accurately. In this pilot study, we assessed the feasibility of using a wearable sensor to evaluate patient-defined goal achievement. The wearable sensor measured daily mobility and sleep performance, including length of walking bouts, time sitting, postural transitions, and sleep duration. Patients wore pendant sensors for 48 hours at baseline (before PPC conversations) and 3-6 month follow-up. We present a case in which remote monitoring exhibited evidence of goal achievement and another case in which monitoring exhibited failure to achieve a goal. In the former, the patient set a goal of walking his dogs daily. At baseline, mobility performance suggested that he was not engaged in this activity. At follow-up, in contrast, all parameters showed accomplishment of the patient’s goal. In the latter case, the patient set a goal of maintaining his habit of walking a mile per day. At follow-up, sensor measures showed that the patient was not making progress on this goal. Conclusion: Remote monitoring using wearable sensors can provide objective information about goal achievement for patients with dementia. Sensor measurement can assist clinicians in evaluating goal achievement for patients with dementia and adjusting care based on these measures.

Characterizing material transitions in large-scale Additive Manufacturing

Integrating Multiple Materials (MM) into large-scale Additive Manufacturing (AM) is a key for various industrial applications wishing to incorporate site-specific properties into geometrically complex designs that are difficult to manufacture with traditional techniques. Printing with multiple materials is typically accomplished by using layers as natural material boundaries, but having the capability to switch between materials within a single layer without pausing would further expand MM possibilities. This study used Cincinnati Incorporated’s Big Area Additive Manufacturing (BAAM) system to explore material transitions with a novel dual-hopper that enables in-situ material blending of a pelletized feedstock. Constructing MM and functionally graded material (FGM) structures requires depositing a specific material composition at a specific geometric location to achieve a desired performance. Accurately implementing this with the BAAM’s blended extrusion system requires a thorough understanding of the transition between distinct material compositions. This study characterizes a step-change transition between neat acrylonitrile butadiene styrene (ABS) and carbon fiber-reinforced ABS. Three distinct techniques were compared for analyzing the fiber content, and the transition zone between materials was characterized as a function of transition direction. The transition process was consistent to within 0.7 wt% carbon fiber variation between different layers and prints. The transition between materials was found to be directionally dependent, with ABS to CF/ABS having a transition length of 3.5 m compared to 3.2 m for CF/ABS to ABS. Furthermore, the transition from Material A to Material B was found to be repeatable with a possible variance in transition length of 0.3 m.

Numerical simulation and experiment of dimple for flexible clamp multi-point stretch forming of spherical part

The structural character of flexible clamp stretch forming machine is introduced. The real stress and strain curve of Aluminium alloy 2024-O is tested by uniaxial tensile. Numerical simulation of dimple for spherical part with flexible clamp multi-point stretch forming (FCMPSF) is carried out by ABAQUS, and the generated result of dimple is elaborated. The effects of transitional length, sheet thickness and spherical radius on dimple are investigated by lots of numerical simulations, and the thickness strain of spherical part along the objective line ef with different forming suitation is extracted. Then polyurethane sheet is chosen as elastic cushion to depress dimple, and series of numerical simulations are put forward for spherical part of FCMPSF with different thicknesses of polyurethane sheet. Finally, FCMPSF experiment is done and forming precision is measured. Consequently, the spherical part has good forming shape and surface accuracy, which illustrates that the FCMPSF technology is feasible and practional to forming three-dimensional surface part.

Experimental Phonetic comparative Analysis of Russian glide /j/ series of Korean Learners of Russian and Russian Female Speakers

The main purpose of this study is to examine how the pronunciation of Korean learners of Russian differs from the Russian female speaker’s pronunciation through the experimental phonetic method of Russian glide /j/ series /je, ja, jo, ju/. Through this study, five conclusions were reached. First, the length of the onset of Russian female speakers was more than twice as long as the onset of Korean learners of Russian in all series of /je, ja, jo, and ju/. In both groups, the longest series was [je] series, and the shortest series was [ja] series. In the same series, the largest difference between the two groups was [jo] series, and the smallest difference was [ju] series. In addition, the onset of a Russian female speaker was not only distinguished from Korean learners of Russian in length, but also showed a distinct difference in sound wave quality. In Russian female speakers, all subjects produced a highly fricative note, and Korean learners of Russian produced only one subject with a fricative note. Second, the length of transition of Russian female speakers is 22% longer than that of Korean learners of Russian, the length of the glide is 63% longer, and the length of the /j/ series is 35% longer. Russian female speakers are longer than Korean learners of Russian in length of onset, transition, glide, and /j/-series, but the rate of transition to glides is 13.9% less for Russian female speakers than Korean learners of Russian. This means that the transfer takes place more rapidly in Russian female speakers than in Korean learners of Russian. In addition, the ratio of glide in the /j/-series is 8.76% higher for Russian female speakers than for Korean learners of Russian. This means that the proportion of glide in the /j/-series of Russian female speakers is greater than that of Korean learners of Russian. Third, the most striking difference in the intensity of Russian female speakers and Korean learners of Russian is that the intensity of Russian female speakers in the opening tone is significantly lower than that of Korean learners of Russian. The difference in intensity between the two groups is 4.64dB in the opening tone. In addition, the intensity of Russian female speakers rises sharply as they progress from the beginning to the transition, but the intensity of Korean learners of Russian gradually rises. In this part, Russian female speakers differ by 7.34dB from Korean learners of Russian. And, in the difference in intensity between the opening and closing vowels, the Russian female speaker differs by 6.82dB compared to the Korean Russian learner. In the case of Russian female speakers, it can be seen that the intensity of the opening and closing vowels is distinguished from each other. Third, the intensity of Russian female speakers in the onset is significantly lower than that of Korean learners of Russian. The difference in intensity between the two groups in the onset is 4.64dB. And when moving from the onset to the transition, the intensity of Russian female speakers rises steeply, but the intensity of Korean learners of Russian rises gradually. In the two groups, the difference in intensity between the transition and landing sound is 7.34 dB. And In the two groups, the difference in intensity between the onset and offset was 6.82dB greater for Russian female speakers than for Korean learners of Russian. Therefore, it can be seen that Russian female speakers clearly distinguish the intensity of the onset and offset from each other. Fourth, if you look at the changes in F1 at three points of M1, M2, M3, in the case of Russian female speakers, the change in F1 is not large in the M1M2 section, but rises rapidly in the M2M3 section, but in the case of Korean learners of Russian, the change in F1 rises continuously in the M1M2 section and M2M3 section. By series, in the case of Russian female speakers, all series are gathered at the M1 point, and then F1 does not change significantly in the process of going

Anisotropic thermal conductivity of the nanoparticles embedded GaSb thin film semiconductor

The prior theoretical model shows that GaSb is one of the few non-alloy semiconductors showing phonons ballistic effect in the thermal conductivity. However, no previous literature had been reported on the experimental measurements on the quasi-ballistic thermal transport of the GaSb thin film. In this paper, we employed the time-domain thermoreflectance (TDTR) to study the thermal transport of nanoparticles embedded GaSb thin film. Our measurements results provide first experimental evidence to verify the quasi-ballistic effect in the thermal transport of the GaSb thin film. The apparent cross-plane thermal conductivity of pure GaSb sample drops ∼15% when the pump laser modulation frequency is increased from 0.8 MHz to 10 MHz at room temperature. To further understand the thermal transport mechanism, Tempered Lévy analysis is employed to study the quasi-ballistic effect of the GaSb thin film. The model shows that GaSb thin film thermal transport has a superdiffusion exponent, = 1.51 ± 0.23 and Lévy-Fourier transition length, r LF = 0.19 ± 0.13 µm. Both obtained values via Tempered Lévy indicates the quasi-ballistic transport phenomena in GaSb thin film. However, this frequency dependence of the cross-plane thermal conductivity will disappear in the presence of the 3%–20% ErSb nanoparticles. Another thermal transport mechanism, i.e. anisotropic thermal transport, can be observed in GaSb thin film. The ratio of in- to cross-plane thermal conductivity varies from ∼0.2 to ∼0.7 in the 0%–20% ErSb nanoparticles volume concentrations. Detailed temperature dependence of the in-plane thermal conductivity of ErSb:GaSb samples with 0%–20% are also included in the paper for the understanding of the scattering mechanism in the thin film thermal transport. With enhanced understanding of the quasi-ballistic and anisotropic thin film thermal transport, our results might improve the thermal management efficiency of the GaSb devices.

Transition radiation in an infinite one-dimensional structure interacting with a moving oscillator—the Green’s function method

Transition zones in railway tracks are areas with considerable variation of track properties (e.g., foundation stiffness) which may cause strong amplification of the response, leading to rapid degradation of the track geometry. Two possible indicators of degradation in the supporting structure are identified, namely the wheel-rail contact force and the power/energy input by the vehicle. This paper analyses the influence of accounting for the interaction between the vehicle and the supporting structure on the contact force and on the power/energy input. To this end, a one-dimensional model is formulated, consisting of an infinite Euler-Bernoulli beam resting on a locally inhomogeneous Kelvin foundation, interacting with a moving loaded oscillator that has a nonlinear Hertzian spring. The solution is obtained using the Green’s-function method. To obtain the Green’s function of the inhomogeneous and infinite beam-foundation sub-system, the finite difference method is used for the spatial discretization and non-reflective boundary conditions are applied. Accounting for the interaction between the moving oscillator and the supporting structure generally leads to stronger wave radiation, caused by the variation of the vertical momentum of the moving mass. Results show that for relatively high velocity and small transition length, the maximum contact force as well as the energy input exhibit a significant increase compared to the moving constant load case. Furthermore, for relatively high velocities, the maximum contact force also increases significantly with increasing stiffness dissimilarity, findings which supplement the existing literature. Finally, the two degradation indicators can be used in the preliminary stages of design to assess the performance of railway track transition zones.

Hydrodynamics of gas/shear-thinning liquid two-phase flow in a co-flow mini-channel: Flow pattern and bubble length

The flow patterns and bubble characteristics formed during gas–liquid flows in a circular co-flow mini-channel with carboxymethyl cellulose (CMC) aqueous solutions are investigated experimentally. The pattern transition and bubble length are elucidated by systematically analyzing the influences of the various factors of the ratio of gas–liquid flow rates, CMC solution mass fraction, and surfactant [sodium dodecyl sulfate (SDS)] mass fraction. Five kinds of flow regimes, namely, bubbly flow, Taylor flow, Taylor-annular flow, annular flow, and churn flow, are identified visually in the fully developed region of the inlet side of the channel, and a universal flow-regime map in terms of the gas and liquid inlet flow rates is constructed using water, CMC solution, and polyacrylamide solution to cover a broad range of material properties. It is found that the ratio of gas–liquid flow rates has a remarkable influence on the flow pattern transitions. The CMC solution mass fraction and SDS mass fraction can also affect the flow-regime map by varying the flow drag force and surface tension acting on the bubble in the mini-channel. The bubble length increases with the ratio of gas–liquid flow rates but decreases with the increase in the CMC fraction and SDS fraction. Based on consideration of the rheological properties of the liquid, a scaling law of bubble length in a co-flow mini-channel with shear-thinning liquids is developed, and the results predicted by it can agree with the measurement data very well under present conditions.

Robust motion in-betweening

In this work we present a novel, robust transition generation technique that can serve as a new tool for 3D animators, based on adversarial recurrent neural networks. The system synthesises high-quality motions that use temporally-sparse keyframes as animation constraints. This is reminiscent of the job of in-betweening in traditional animation pipelines, in which an animator draws motion frames between provided keyframes. We first show that a state-of-the-art motion prediction model cannot be easily converted into a robust transition generator when only adding conditioning information about future keyframes. To solve this problem, we then propose two novel additive embedding modifiers that are applied at each timestep to latent representations encoded inside the network's architecture. One modifier is a time-to-arrival embedding that allows variations of the transition length with a single model. The other is a scheduled target noise vector that allows the system to be robust to target distortions and to sample different transitions given fixed keyframes. To qualitatively evaluate our method, we present a custom MotionBuilder plugin that uses our trained model to perform in-betweening in production scenarios. To quantitatively evaluate performance on transitions and generalizations to longer time horizons, we present well-defined in-betweening benchmarks on a subset of the widely used Human3.6M dataset and on LaFAN1, a novel high quality motion capture dataset that is more appropriate for transition generation. We are releasing this new dataset along with this work, with accompanying code for reproducing our baseline results.