Asymmetric Geometry Research Articles

1D Mathematical Model Development for Prediction and Mitigation of Vehicle Pull Considering Suspension Asymmetry and Tire Parameters

<div class="section abstract"><div class="htmlview paragraph">Error in suspension asymmetry or tire parameters may lead to vehicle drifting laterally from its intended straight-line path, which is called vehicle pull. Driver then needs to apply constant steering correction to maintain the vehicle in straight line which will lead to high driver fatigue and deteriorate driving experience. Manufacturing a perfectly symmetric suspension system is impractical, however an insight into the manufacturing tolerances of suspension system at the early design stage can be extremely useful. Also tire force and moment parameters at straight line operation and its maximum allowable variations will help in defining the tire parameter specifications and tolerances.</div><div class="htmlview paragraph">The objective of this study was to develop a 1D model of suspension and tire system which can predict the torque experienced in steering and drift of the vehicle from straight line due to the tire force and moment and asymmetric suspension geometry. The model assumes small tire slip angles (as the vehicle is running in straight line), rigid steering system and constant vehicle speed. Second part of the work focused on the sensitivity of suspension and tire parameters on vehicle pull and identifying the tolerance limits to mitigate vehicle pull. The developed model has been validated against the observation from physical testing for different tire combinations.</div><div class="htmlview paragraph">Modelling of suspension asymmetries in Multi Body Dynamics (MBD) domain is time consuming and Pacejka formulation of tire will for manufacturing variations will require multiple tire testing. The tool discussed in this paper can be used for quick evaluation of vehicle pull, within a fraction of time of that required for MBD. Additionally, the tool is can be used to predict the limits of suspension camber, caster, kingpin inclination (KPI) and tire parameters such as conicity, plysteer and ply residual aligning torque (PRAT) etc. This information can further be used for defining the tire manufacturing tolerances.</div></div>

Relativistic electron-impact ionization of hydrogen atom from its metastable 2S-state in the symmetric/asymmetric coplanar geometries

In this paper, we present a detailed analytical computation of the triple differential cross sections, in the first Born approximation, for the relativistic electron-impact ionization of hydrogen atom in the metastable 2S-state in the symmetric and asymmetric coplanar geometries. The process is investigated by using the relativistic Dirac-formalism where the effects of spin and relativity are taken into account. It is shown that the nonrelativistic limit is accurately reproduced when applying low incident kinetic energies. At high energies, relativistic and spin effects are found to significantly affect the triple differential cross sections. The numerical results obtained for the triple differential cross section are compared with some other theoretical results in the nonrelativistic regime for asymmetric coplanar geometry. For this particular process and in the absence of any experimental data and theoretical models at high energies for the triple differential cross sections, the results of our calculated relativistic total cross section are compared with available theoretical and experimental results. We hope that the present study will provide significant contribution to future experiments.

Pseudorapidity distributions of charged particles in pp(), p(d)A and AA collisions using Tsallis thermodynamics

The pseudorapidity distributions of charged particles measured in p + p() collisions for energies ranging from GeV to 13 TeV and A + A collisions at RHIC and LHC are investigated in the fireball model with Tsallis thermodynamics. We assume that the rapidity axis is populated with fireballs following q-Gaussian distribution and the charged particles follow the Tsallis distribution in the fireball. We also extend the fireball model to asymmetric collision systems, i.e. d + Au collisions at GeV and p + Pb collisions at TeV, by taking into account the asymmetric geometry configuration. The model can fit the experimental data well for all the collision systems and centralities investigated. The collision energy and centrality dependence of the model parameters for the symmetric (asymmetric) collision system, i.e. the central position y 0 (y 0a , y 0A ) and its width σ (σ a , σ A ) of the fireball distribution, are also investigated and discussed. Our results suggest that the fireball model with Tsallis thermodynamics can be used as a universal framework for the pseudorapidity distributions of charged particles in high energy collisions at RHIC and LHC.

Mechanical design of an asymmetric-deformation-driven rotating machinery

Rotating, as a recurring motion adopted for industrial rotating machinery, has been rarely studied in the development of advanced robotics until recently. The underlying mechanisms that induce the rolling locomotion and the structural and mechanical designs for rotatory machinery remain largely elusive. Herein, we conduct theoretical analyses and numerical simulations for a self-propelled rotating locomotion consisted of a ring with asymmetric deformations upon actuation. The driving force derived from the barycenter offset due to the asymmetric deformations is quantitatively analyzed. Using a typical energy balance theory, the analytical solution for the locomotion speed of the ring is obtained and this speed is found to be determined by the asymmetric geometry designs, and the friction, viscous resistance, and adhesion hysteresis of the system. The numerical simulations further validated our theoretical predictions, demonstrating that a rolling locomotion can be realized by the ring structure with asymmetric designs of the actuation field. The present study establishes the quantitative correlations between the rotating performance and the key structural and mechanical parameters that will guide the design and manufacturing of soft rolling robots and rotating machinery at different length scales.

Sedimentological and geochemical characteristics of Lower Jurassic Sandstones from Gümüşhane, NE Turkey: implications for source to sink processes, paleoenvironmental conditions, provenance and tectonic settings

ABSTRACT The eastern Sakarya Zone (SZ), one of the Alpine Himalayan Belt’s main components, has complex Mesozoic–Cenozoic geodynamic evolution, which remains controversial. Early-Middle Jurassic volcano-sedimentary successions (Şenköy Formation) extensively outcrops in Gümüşhane region, NE Turkey. It is regarded as a critical unit to understand the Mesozoic tectonic evolution of the eastern Sakarya Zone. One of the Şenköy Formation’s predominant units is sandstone succession, preserving implications for paleoenvironmental conditions and tectono-sedimentary development of Neotethys Ocean. Thus, a combined analysis of comprehensive petrography, whole-rock major, trace and rare earth element data is carried out on the sandstones, which are well constrained as late Sinemurian- Pliensbachian. The sandstones are mainly arkosic to lithic arenites in lithology showing poor textural maturities. They are mostly represented by relatively high ICV, low CIA, high K2O/Al2O3, Fe2O3+ MgO, TiO2, Th/U, pronounced negative Eu anomaly, enriched LREEs, elevated GdN/YbN, low Ce/Ce*, Ni/Co, La/V and Zr/Ti. The petrographic and geochemical characteristics imply that the sediments may have experienced relatively low chemical weathering processes and slight reworking and recycling processes with a short transport distance before deposition in the basin. Early Jurassic sandstone successions were interpreted as a transgressive series, showing a predominantly open sea environment with oxidizing paleoenvironmental conditions. The sandstone samples’ paleoenvironment is likely to be located along the southern margin of the arc and the Neotethyan basin to the south. The extensional and trans-extensional tectonic regime might have played an essential role in controlling the basin’s isolated-half graben and/or asymmetric geometry, leading to changes in the provenance of studied sandstone samples. Thus, the geochemical signature differences are probably associated with basement-related proximal origins and minor effects of the multi-phases petrogenesis that experienced different source to sink processes. Early Jurassic sandstones were probably derived from multi-genetic source rocks, including (i) granite and (ii) metamorphic rocks. Our new data has also indicated that other source rocks can include mafic to felsic volcanic succession. The possible provenance for granitic pluton and metamorphic rocks can be provided by the Hercynian heterogenetic crystalline basement widespread throughout the SZ. However, mafic to felsic volcanic rock source is likely to be associated with the pre-Early Jurassic nearby volcanic-arc, which is rarely recorded in the eastern SZ. The source rock signatures may imply a close genetic link with ancient magmatic-arc generation due to the southward subduction of Palaeotethys.

Skyrmion ratchet in funnel geometries

Using a particle-based model, we simulate the behavior of a skyrmion under the influence of asymmetric funnel geometries and ac driving at zero temperature. We specifically investigate possibilities for controlling the skyrmion motion by harnessing a ratchet effect. Our results show that as the amplitude of a unidirectional ac drive is increased, the skyrmion can be set into motion along either the easy or hard direction of the funnel depending on the ac driving direction. When the ac drive is parallel to the funnel axis, the skyrmion flows in the easy direction and its average velocity is quantized. In contrast, when the ac drive is perpendicular to the funnel axis, a Magnus-induced ratchet effect occurs, and the skyrmion moves along the hard direction with a constant average velocity. For biharmonic ac driving of equal amplitude along both the parallel and perpendicular directions, we observe a reentrant pinning phase where the skyrmion ratchet vanishes. For asymmetric biharmonic ac drives, the skyrmion exhibits a combination of effects and can move in either the easy or hard direction depending on the configuration of the ac drives. These results indicate that it is possible to achieve controlled skyrmion motion using funnel geometries, and we discuss ways in which this could be harnessed to perform data transfer operations.

Probing the profile of bulk matter in p+Pb collisions via directed flow of heavy quarks

The asymmetric initial geometry in $p+\text{Pb}$ collisions provide an opportunity to probe the initial matter distribution in these collisions. Using a multiphase transport (AMPT) model, we have studied the production of light and heavy quark particles in $p+\text{Pb}$ collisions at $\sqrt{{s}_{NN}}$ = 5.02 TeV. The pseudorapidity density $(dN/d\ensuremath{\eta})$ and elliptic flow $({v}_{2})$ of light quark particles from AMPT reasonably agrees with the measurements by ALICE. We predicted the directed flow of light and heavy quarks in $p+\text{Pb}$ collisions. The ${v}_{1}$ of both light and heavy quark mesons show a nontrivial ${p}_{T}$ dependence in $p$- and Pb-going directions. When integrated over the transverse momentum range 0 $<{p}_{T}<5$ GeV/c, the magnitude of heavy quark directed flow $({v}_{1})$ is found to be 15 times larger than the light quark species in the Pb-going direction while the same in the $p$-going direction are comparable. The light and heavy quarks ${v}_{1}$ may offer the possibility to probe the initial matter density as well as the collective dynamics in $p+\text{Pb}$ collisions.

Hot punching for loading of biodegradable microcontainers with budesonide-Soluplus film.

Micro-reservoir based drug delivery systems have the potential to provide targeted drug release locally in the intestine, i.e. at the inflamed areas of the intestine of patients with inflammatory bowel disease (IBD). In this study, microcontainers with a diameter of 300µm and a height of 100µm, asymmetrical geometry and the possibility to provide unidirectional release, are fabricated in the biodegradable polymer poly-ɛ-caprolactone (PCL) using hot punching. As a first step towards local treatment of IBD, a novel method for loading of microcontainers with the corticosteroid budesonide is developed. For this purpose, a budesonide-Soluplus drug-polymer film is prepared by spin coating and loaded into the microcontainer reservoirs using hot punching. The processing parameters are optimized to achieve a complete loading of a large number of containers in a single step. A poly(lactic-co-glycolic acid) (PLGA) 50:50 lid is subsequently applied by spray coating. Solid-state characterization indicates that the drug is in an amorphous state in the drug-polymer films and the in vitro drug release profile showed a 68% release over 10h. The results demonstrate that hot punching can be employed both as a production and loading method for PCL microcontainers with the perspective of local treatment of IBD.

Tunable carbon nanotube diode with varying asymmetric geometry

We propose and demonstrate a carbon nanotube (CNT)-based field emission nanoscale diode to realize a fully integrated nanoscale system, namely, a true nanosystem. To the best of our knowledge, this is the first time a nanodiode simultaneously achieves ease of fabrication and individual tunability of multiple CNT diodes on the nanoscale on the same substrate in a one-time process. A nanodiode comprises a single-wall CNT cathode placed on a substrate, layered insulator, and metal anode. The proposed nanodiode allows us to adjust the turn-on voltage from 1 to 2.4 V by varying the surface area of the anode. Furthermore, as an example of a basic nano-electronic system, nanodiode-based fundamental logic gates (OR and NAND) are demonstrated on a CNT. We propose a theoretical model that derives the theoretical I–V characteristics based on the image-charge method to design the nanodiode quickly. The results in this study contribute to the development of carbon-based nanoelectronic systems.

Categorical Exploratory Data Analysis: From Multiclass Classification and Response Manifold Analytics Perspectives of Baseball Pitching Dynamics.

All features of any data type are universally equipped with categorical nature revealed through histograms. A contingency table framed by two histograms affords directional and mutual associations based on rescaled conditional Shannon entropies for any feature-pair. The heatmap of the mutual association matrix of all features becomes a roadmap showing which features are highly associative with which features. We develop our data analysis paradigm called categorical exploratory data analysis (CEDA) with this heatmap as a foundation. CEDA is demonstrated to provide new resolutions for two topics: multiclass classification (MCC) with one single categorical response variable and response manifold analytics (RMA) with multiple response variables. We compute visible and explainable information contents with multiscale and heterogeneous deterministic and stochastic structures in both topics. MCC involves all feature-group specific mixing geometries of labeled high-dimensional point-clouds. Upon each identified feature-group, we devise an indirect distance measure, a robust label embedding tree (LET), and a series of tree-based binary competitions to discover and present asymmetric mixing geometries. Then, a chain of complementary feature-groups offers a collection of mixing geometric pattern-categories with multiple perspective views. RMA studies a system’s regulating principles via multiple dimensional manifolds jointly constituted by targeted multiple response features and selected major covariate features. This manifold is marked with categorical localities reflecting major effects. Diverse minor effects are checked and identified across all localities for heterogeneity. Both MCC and RMA information contents are computed for data’s information content with predictive inferences as by-products. We illustrate CEDA developments via Iris data and demonstrate its applications on data taken from the PITCHf/x database.

Observation of parametric X-ray radiation for the asymmetric Laue geometry

Angular distributions of parametric X-ray radiation from 255-MeV electrons in a thin Si crystal have been investigated for asymmetric Laue geometries using an imaging plate as a two-dimensional position-sensitive X-ray detector. The peak intensities of parametric X-ray radiation observed for (111) and (1¯1¯ 1) reflections, normalized by taking into account the effective target thickness and the transmission fraction of X-rays in the crystal, coincided within several percent. A large intensity difference depending on the asymmetry parameter, which is predicted by a dynamical theory dealing with the asymmetric Laue geometry, was not observed under the present experimental conditions. This indicates that the dependence of angular distributions of parametric X-ray radiation on the asymmetry parameter is negligibly weak, i.e., that it can be well explained by the well-established kinematical theory and dynamical theory as well as those for symmetric Laue and Bragg geometries.

Comment on “A study on improvement of discharge characteristic by using a transformer in a capacitively coupled plasma” [Phys. Plasmas 22, 123504 (2015)

In the paper [Y.C. Kim et al., Phys. Plasmas 22, 123504 (2015)], the plasma density in radio frequency (RF) capacitively coupled plasma was increased by introducing a step-down ferrite-core transformer into a conventional type-T impedance matching network. The authors ascribed the increment in plasma density to the reduction of DC self-bias. Although this correlation was roughly right, but behaviors of the DC self-bias in the asymmetric RF discharge that was non-linearly interacted with the external circuit were not discussed. In practical applications, this approach of increasing plasma density will be limited by the rapid increase in power loss in step-down ferrite-core transformer operating in high-power 13.56 MHz discharges and the still high DC self-bias governed by the asymmetric geometry.

Characteristics of cavity collapse behind a high-speed projectile entering the water

We investigate cavity collapse regimes behind high-speed projectiles entering the water. Using numerical simulations, we confirmed two different collapse phenomena: deep pinch-off and consecutive collapse. We performed a theoretical analysis to develop the relationship between projectile motion and cavity evolution. We found that projectile acceleration is the most significant factor determining the initial cavity collapse. There is a critical acceleration determining the direction of cavity collapse at the location of deep pinch-off. The pressure field is obviously affected by the collapse. The increase in pressure induced by surface pinch-off accelerates the collapse at the cavity tail. Because of the impact of surface pinch-off, consecutive collapse can be seen if a projectile reaches critical acceleration near a free surface. Otherwise, the cavity will pinch off at a distance from the surface of the water and form a deep pinch-off. Particular attention is paid to the impact of consecutive collapse on the projectile. Numerical calculations show that cavity collapse and a high-speed water jet have an obvious impact on the stability of the projectile. The jet exerts great pressure on the projectile, and the accompanying splash droplets contaminate the cavity wall. Cavity pulsation and the asymmetric geometry of the projectile-cavity system aggravate attitude deflection.

Hierarchical Hydrophilic/Hydrophobic/Bumpy Janus Membrane Fabricated by Femtosecond Laser Ablation for Highly Efficient Fog Harvesting.

The shortage of freshwater is threatening sustainable economic development and ecological security worldwide. Janus membrane, as a highly efficient method to collect the invisible fog water in the wet environment, is still hindered by some inherent limitations: (1) poor condensation of fog droplets on the superhydrophobic side due to the ultralow adhesive force of droplets with substrate and (2) insufficient detachment of droplets from the superhydrophilic side in time, which hampers the continuous water transport in the micropores. Herein, inspired by the desert beetle's back with alternating hydrophobic/hydrophilic bumps and the cactus thorn with an asymmetric geometry, we design and fabricate a kind of hierarchical hydrophilic/hydrophobic/bumpy Janus (HHHBJ) membrane by femtosecond laser ablation on an aluminum membrane to achieve the self-driven fog collection, which achieves over 250% enhancement in the water collection efficiency over the conventional Janus membrane. Even when the mist flow is applied to the surface at an incident angle of 45°, the collection efficiency increases by 600%. The mechanism of the HHHBJ film with excellent fog collection efficiency is mainly related to the continuous efficient fog condensation on the top surface and droplet removal on the bottom surface in time. We believe the proposed multi-bioinspired HHHBJ film with droplet self-driven collection ability provides insights to conceive and construct a highly efficient fog collection system in broad fields.

An Experimental Study on Frictional Losses of Coated Piston Rings with Symmetric and Asymmetric Geometry

An Experimental Study on Frictional Losses of Coated Piston Rings with Symmetric and Asymmetric Geometry

Early turbulence and pulsatile flows enhance diodicity of Tesla\u2019s macrofluidic valve

Microfluidics has enabled a revolution in the manipulation of small volumes of fluids. Controlling flows at larger scales and faster rates, or macrofluidics, has broad applications but involves the unique complexities of inertial flow physics. We show how such effects are exploited in a device proposed by Nikola Tesla that acts as a diode or valve whose asymmetric internal geometry leads to direction-dependent fluidic resistance. Systematic tests for steady forcing conditions reveal that diodicity turns on abruptly at Reynolds number {rm{Re}}approx 200 and is accompanied by nonlinear pressure-flux scaling and flow instabilities, suggesting a laminar-to-turbulent transition that is triggered at unusually low {rm{Re}}. To assess performance for unsteady forcing, we devise a circuit that functions as an AC-to-DC converter, rectifier, or pump in which diodes transform imposed oscillations into directed flow. Our results confirm Tesla’s conjecture that diodic performance is boosted for pulsatile flows. The connections between diodicity, early turbulence and pulsatility uncovered here can inform applications in fluidic mixing and pumping.

Ridge jump reorientation of the South China Sea revealed by high‐resolution magnetic data

AbstractWe establish a high‐resolution magnetic isochron pattern in the East Subbasin (ESB) of the South China Sea (SCS) based on recently collected magnetic data, which provides an updated age of seafloor spreading in the ESB and reveals a new type of ridge reorientation. Seafloor spreading in the ESB initiated at Chron 11n.1r (29.7 Ma) and ceased shortly after Chron 5Br (15.6 Ma). Successive ridge jumps occurred between Chrons 9r and 7n, which explains the substantial asymmetric geometry of the ESB. Furthermore, the ridge reorientation associated with ridge jumps highlights a new ridge reorientation model in which the ridge jumps off‐axis and reorients synchronously to adapt to the new direction of seafloor spreading. In the ESB, this type of reorientation responds more rapidly to changes in the direction of plate motion than gradual ridge rotation.

Planar Multilayered 2D GeAs Schottky Photodiode for High-Performance Visible-Near-Infrared Photodetection.

Novel group IV - V 2D semiconductors (e.g., GeAs and SiAs) have arisen as an attractive candidate for broad-band photodetection and optoelectronic applications. This 2D family has a wide tunable band gap, excellent thermodynamic stability, and strong in-plane anisotropy. However, their photonic and optoelectronic properties have not been extensively explored so far. This work demonstrates a broadband back-to-back metal-semiconductor-metal (MSM) Schottky photodiode with asymmetric contact geometries based on multilayered 2D GeAs. The photodetector exhibited a Schottky barrier height (SBH) in the range of 0.40-0.49 eV. Additionally, it showed a low dark current of 1.8 nA with stable, reproducible, and excellent broadband spectral response from UV to optical communication wavelengths. The highest measured responsivity in the visible is 905 A/W at 660 nm wavelength and 98 A/W for 1064 nm near-infrared at an applied voltage of -3 V and zero back gate. Most notably, the planner configuration of this GeAs photodetector showed a low detector capacitance below 1.2 pf and low voltage operation (<1 V). The stability and broadband response of the device are promising for this 2D material's application in advanced optoelectronic devices.

Controls on Asymmetric Rift Dynamics: Numerical Modeling of Strain Localization and Fault Evolution in the Kenya Rift

AbstractComplex, time‐dependent, and asymmetric rift geometries are observed throughout the East African Rift System (EARS) and are well documented, for instance, in the Kenya Rift. To unravel asymmetric rifting processes in this region, we conduct 2D geodynamic models. We use the finite element software ASPECT employing visco‐plastic rheologies, mesh‐refinement, distributed random noise seeding, and a free surface. In contrast to many previous numerical modeling studies that aimed at understanding final rifted margin symmetry, we explicitly focus on initial rifting stages to assess geodynamic controls on strain localization and fault evolution. We thereby link to geological and geophysical observations from the Southern and Central Kenya Rift. Our models suggest a three‐stage early rift evolution that dynamically bridges previously inferred fault‐configuration phases of the eastern EARS branch: (1) accommodation of initial strain localization by a single border fault and flexure of the hanging‐wall crust, (2) faulting in the hanging‐wall and increasing upper‐crustal faulting in the rift‐basin center, and (3) loss of pronounced early stage asymmetry prior to basinward localization of deformation. This evolution may provide a template for understanding early extensional faulting in other branches of the East African Rift and in asymmetric rifts worldwide. By modifying the initial random noise distribution that approximates small‐scale tectonic inheritance, we show that a spectrum of first‐order fault configurations with variable symmetry can be produced in models with an otherwise identical setup. This approach sheds new light on along‐strike rift variability controls in active asymmetric rifts and proximal rifted margins.

Sequential Superassembly of Nanofiber Arrays to Carbonaceous Ordered Mesoporous Nanowires and Their Heterostructure Membranes for Osmotic Energy Conversion.

The capture of sustainable energy from a salinity gradient, in particular, using renewable biomass-derived functional materials, has attracted significant attention. In order to convert osmotic energy to electricity, many membrane materials with nanofluidic channels have been developed. However, the high cost, complex preparation process, and low output power density still restrict the practical application of traditional membranes. Herein, we report the synthesis of highly flexible and mechanically robust nanofiber-arrays-based carbonaceous ordered mesoporous nanowires (CMWs) through a simple and straightforward soft-templating hydrothermal carbonization approach. This sequential superassembly strategy shows a high yield and great versatility in controlling the dimensions of CMWs with the aspect ratio changes from about 3 to 39. Furthermore, these CMWs can be used as novel building blocks to construct functional hybrid membranes on macroporous alumina. This nanofluidic membrane with asymmetric geometry and charge polarity exhibits low resistance and high-performance energy conversion. This work opens a solution-based route for the one-pot preparation of CMWs and functional heterostructure membranes for various applications.