Motional Resistance Research Articles

Bayesian calibration of Vehicle-Terrain Interface algorithms for wheeled vehicles on loose sands

The Vehicle-Terrain Interface (VTI) model is commonly used to predict off-road mobility to support virtual prototyping. The Database Records for Off-road Vehicle Environments (DROVE), a recently developed database of tests conducted with wheeled vehicles operating on loose, dry sand, is used to calibrate three equations used within the VTI model: drawbar pull, traction, and motion resistance. A two-stage Bayesian calibration process using the Metropolis algorithm is implemented to improve the performance of the three equations through updating of their coefficients. Convergence of the Bayesian calibration process to a calibrated model is established through evaluation of two indicators of convergence. Improvements in root-mean square error (RMSE) are shown for all three equations: 17.7% for drawbar pull, 5.5% for traction, and 23.1% for motion resistance. Improvements are also seen in the coefficient of determination (R2) performance of the equations for drawbar pull, 2.8%, and motion resistance, 2.5%. Improvements are also demonstrated in the coefficient of determination for drawbar pull, 2.8%, and motion resistance, 2.5%, equations, while the calibrated traction equation performs similar to the VTI equation. A randomly selected test dataset of about 10% of the relevant observations from DROVE is used to validate the performance of each calibrated equation.

New algorithms for predicting longitudinal motion resistance of wheels on dry sand

Predicting the resisting forces against a vehicle’s wheel during movement in loose sand is critical for optimizing tractive capabilities in desert regions, sand dunes, and beaches. We review existi...

Piezoelectric Bulk Mode Disk Resonator Post-Processed for Enhanced Quality Factor Performance

This paper presents a bulk-mode disk resonator utilizing a transverse piezoelectric actuation technique to drive the single crystalline silicon disk structure in its wine-glass bulk mode of resonance. The device is fabricated by post-processing dies from a commercial microelectromechanical systems process and combines high quality factor and relatively low motional resistance. Post-process fabrication steps are used to reduce the width of the anchor beam supports, and consequently reduce the anchor losses. This results in a factor of 3 increase in the quality factor. Post-processed resonators were measured to have resonance frequencies of 23 MHz and quality factors of 13000 in atmospheric pressure, increasing to 31000 in 1 mTorr vacuum. The devices also demonstrate motional resistances of 21 kQ in atmospheric pressure, reducing to 8.8 kQ in 1 mTorr vacuum without requiring any dc voltage for operation.

Development of a multi-year database to assess off-road mobility algorithms in fine-grained soils

A gap in off-road mobility is the availability of the test data necessary for the development and validation of tyre, track and soil models. This paper presents the results from a multi-year program to create the database records for off-road vehicle environments (DROVE), a consolidated database of laboratory and field test results. A fine-grained soil component was added to DROVE by compiling 2657 test results. Performance parameters including drawbar pull, motion resistance, torque, sinkage, and slip were included in the database. The database was used to evaluate the accuracy of existing algorithms used in the vehicle-terrain interface (VTI) model. The results indicated that the VTI algorithms can provide reasonable predictions for a few parameters but for others, such as motion resistance, further improvements are warranted. The DROVE dataset can be used for several applications including evaluation of existing mobility models, development of improved algorithms, and validation of numerical simulations.

Magnesium Zinc Oxide Nanostructure-modified Quartz Crystal Microbalance for Dynamic Monitoring of Antibiotic Effects and Antimicrobial Resistance

We demonstrate a magnesium zinc oxide (MZO) nanostructure-modified quartz crystal microbalance (MZOnano-QCM) biosensor to dynamically monitor antimicrobial effects on E. coli and S. cerevisiae. The MZO nanostructures were grown on the top electrode of a standard QCM using metal-organic chemical-vapor deposition (MOCVD). The MZO nanostructures are utilized as the sensing material due to their multifunctionality, biocompatibility, and very large effective sensing surface. The MZO surface-wettability and morphology are controlled, offering high-sensitivity to various biological/biochemical species. The MZOnano-QCM was applied to detect the effects of ampicillin and tetracycline on sensitive and resistant strains of E.coli, as well as effects of amphotericin-B and miconazole on S. cerevisiae through the device's time-dependent frequency shift and motional resistance.

Лубрикация рельсов тяговым локомотивом в составе поезда

Interaction of rolling stock and track is a fundamental physical process while running cars, locomotives and trains on the railway. The Research, Design and Technological Institute of the rolling stock (JSC VNIKTI) for more than twenty years conducting research to reduce cost of energy for traction.The Institute has developed rail lubrication technology performed by locomotive leading the train, but with the improvement: the lubrication of the internal rolling surface of the rail in curve performed by leading locomotive and on sections where lubrication made on side surface of the head of the outer rail - by lubricating cars. This technology can reduce the side impact of the rolling stock on the railway track in curved sections, to reduce resistance to motion while maintaining the length of the braking distance. The effect of reducing the side impact to the track is achieved by reducing the coefficient of friction on the rolling surface of the inner rail and the side surface of the outer rail, which leads to a proportional reduction of transverse forces of creep. Such reduction of transverse forces in creep decreases the normal reaction at the flange of the oncoming wheel and, consequently, reduces motion resistance (reduction in energy consumption for traction), reduce wear, both wheel flanges of rolling stock and rails in curves.Lubrication of rail by traction unit in the train has a broad perspective of application on the railway network of JSC Russian Railways. The minimum cost of additional equipping locomotives with devices automatically applying friction modifiers and manufacture of friction modifiers will payback considerable profit by savings of traction resources and by savings associated with a reduction in regrinding of wheelsets and replacement of rails in curves.

TECHNO-ECONOMIC ASSESSMENT OF THE USE OF WHEELS OF PERSPECTIVE STRUCTURAL SCHEME FOR RAILWAY VEHICLES

Purpose. The article is aimed to the definition of technical and economic efficiency from the use of wheels of perspective structural scheme in the undercarriage of the rail vehicles (wagon). Methodology. The use efficiency of wheels of promising design scheme by reducing the motion resistance and wear of the wheel flanges is estimated by calculated values of estimated annual economic effect of implementation and payback period of the costs required for the development and implementation of the proposed wheel. Non-recurring costs include the cost associated with conducting research and development work, as well as the additional costs required for the manufacture of wheels of promising design scheme. Findings. In the course of computation and analysis of the economic efficiency from introductions of wheels of promising design concept, carried out on the basis of the initial data for the South-West railway, it was determined the profit which can be obtained by reducing the following operating costs: cost of returning the wheel flange on wheel sets; cost of fuel and energy resources for train traction; the value of the idle of cars in the current uncoupling repair; cost of repairs and current maintenance of rail track. In addition, it can be additionally released a number of cars by reducing their downtime. The calculation of net discounted income is carried out with the following assumptions: calculation period; estimated increase in the cost of wheel sets with wheels of promising constructive scheme compared to the model, the values of net profit for the accounting period, which was calculated by calculating the average value minus the cost of research, development and manufacturing of wheelset park with wheels of new design scheme. For a given billing period, the calculated value of the net discounted income was obtained and the payback period of the project was determined. Originality. The approaches to the perfection of design scheme of wheels, used in running gear of railway vehicles were substantiated. Practical value. The calculation method proposed in this publication allows evaluating the technical and economic feasibility of using the wheels of promising design scheme in the running gears of railway vehicles.

Optimum resistance analysis and experimental verification of nonlinear piezoelectric energy harvesting from human motions

The complex dynamic behavior of nonlinear harvesters make it difficult to identify the optimum mechanical and electrical parameters for maximum output power, when compared to linear energy harvesting devices. In addition, the chaotic and multi-frequencies characteristics of responses under realistic human motion excitations provide additional challenges for enhancing the energy harvesting performance, such as the traditional frequency domain method being inappropriate for optimum resistance selection. This paper provides detailed numerical and experimental investigations into the influence of resistance on the efficiency of nonlinear energy harvesting from human motions. Numerical simulations under human motions indicate that optimum resistance of a nonlinear harvester can be attained to maximize the power output. Moreover, simulations of linear and nonlinear harvesters under harmonic excitations verify the effectiveness of frequency dominant method to obtain optimum resistance in the absence of a change in the dynamic behavior of the harvester. However, numerical simulations and experiments are the effective methods when the harvester shows complex dynamic characteristics. Experimental measurements of harvested power under different motion speeds and resistances are in agreement to the numerical analysis for the nonlinear harvester. The results demonstrate the effectiveness of the proposed resistance optimization method for nonlinear energy harvesting from human motions.

Vortex motion and flux-flow resistivity in dirty multiband superconductors

The conductivity of vortex lattices in multiband superconductors with high concentration of impurities is calculated based on microscopic kinetic theory. Both the limits of high and low fields are considered, when the magnetic induction is close to or much smaller than the critical field strength $H_{c2}$, respectively. It is shown that in contrast to single-band superconductors the resistive properties are not universal but depend on the pairing constants and ratios of diffusivities in different bands. The low-field magneto-resistance can strongly exceed Bardeen-Stephen estimation in a quantitative agreement with experimental data for two-band superconductor MgB$_2$.

Mode selection for electrostatic beam resonators based on motional resistance and quality factor.

An analytical comparison between the fundamental mode and higher modes of vibration for an electrostatic beam resonator is presented. Multiple mode numbers can be matched to a desired resonance frequency through appropriate scaling. Therefore, it is important to determine which mode yields the best performance. A dynamic model of the resonator is derived and then used to determine the motional resistance for each mode. The resulting equation provides the basis for comparing performance between modes using motional resistance and quality factor. As a demonstration of the approach, a quality factor model that has been previously validated experimentally is introduced. Numerical results for silicon resonators indicate that the fundamental mode can provide a lower motional resistance and higher quality factor when the resonators under comparison have the same aspect ratio or the same stiffness.

Microstructure Evolution and Creep Properties of a Single Crystal Nickel-Based Superalloy with Various Orientations

By means of creep properties measurement and microstructure observations, the effect of microstructure evolution on creep strength of the single crystal Ni-based alloy with different orientations is investigated. Results show that, during creep at 1040 oC/137 MPa, the γ′ phase in [001]-oriented alloy is transformed into mesh-like N-type rafted structure, the one in [011]-oriented alloy is transformed into the stripe-like rafted structure along [001] direction, the one in [111]-oriented alloy is transformed into the mesh-like rafted structure along (010) plane. The γ′ phase with different configurations results in the different creep resistance of alloys, the sequence of creep resistance of alloys with different orientations are determined to be σ[001] > σ[111] > σ[011]. But after pre-compressed treated along [100] direction of [011] oriented alloy, the γ′ phase in [011] oriented alloy is transformed into the stripe-like rafted structure along [100] direction, which makes the creep life of the alloy enhancing from 11 h to 174 h at 850 oC/400 MPa, and from 74 h to 165 h at 1040 oC/137 MPa. This is attributed to the pre-treatment eliminating the gable channels to form the “labyrinth” structure of γ′ phase, which may increase the resistance of dislocation motion.

Simulation method for determining traction power of ATN–PRT vehicle

The construction of Personal Rapid Transit (PRT) vehicle made within the framework of Eco-Mobility project has been described in the present paper. Key features of the vehicles were identified – e.g. drive with three-phase linear motor with winding on the vehicle and fixed rotor in the road surface, contactless dynamic vehicle powering. Attention was paid to the difference in dynamic properties compared to rail vehicles, related to the lack of the so-called ‘centering mechanism’. A development of a nominal model for the analysis of vehicle drive properties was presented. Results of simulation studies were presented for a vehicle with running-drive system construction, planned for implementation in the city of Rzeszów (Poland). While discussing the problems of building a PRT system, there was a focus on the issue of determining power and traction of the vehicle. A methodology for determining the power and traction energy consumption of the vehicle was presented for assumed conditions of travel on road segments. Input values for the calculation of power are variables describing the curvature (or bends radii) of paths of movement between stops and the course of the current speed. Output values are total traction power or traction energy (where ‘traction’ refers to the power or mechanical work of drive forces). Three basic elements of traction power were isolated: the power of kinetic energy (for acceleration/delay of vehicle movement) basic (to offset the aerodynamic force of motion resistance at constant speed) and additional losses (to offset additional motion resistance forces operating in turns at constant speed). Due to the lack of vehicle prototypes with assumed structure, it was proposed that these components are determined via simulation. The presented results relate to the calculation of demand for power and energy for the planned test section. The scope of further work was indicated: determining the required traction characteristics of electric drive, selecting the best values for supercapacitor’s capacity in the drive system, determining the technical parameters of substation.

Tractor traction performance simulation on differently textured soils and validation: A basic study to make traction and energy requirements accessible to the practice

Several models exist to simulate traction performance of a tractor, however, for most of them a proper experimental validation is missing. Moreover, their possible application for a practical use in a wide range of vehicles, equipment and soil configurations has never been further developed. This study examines a semi-empirical model of soil-tyre interaction, adapted to simulate the traction performance of mechanical front wheel drive tractors, taking into account not only mechanical soil and tyre parameters and static vehicle load but also the multi-pass effect, the load transfer effect, and the theoretical speed ratio between front and rear axles. This model simulates drawbar pull, traction coefficient, traction efficiency, and motion resistance as a function of slip, wheel load, tyre size and pressure. Several traction tests were performed on four Swiss agricultural soils of different type (clay, clay loam, silty loam, and loamy sand) in order to validate the model experimentally. Three tractors of widely ranging power (from 40 to 132kW) and weight (from 24 to 68kN) were used. Tractor configurations were varied by changing tyre pressure and tractor weight. Slip normally ranged between 5 and 30%. In most of the cases the model simulated drawbar pull as well as its variations due to changes in tyre pressure, wheel load, and soil strength reliably for practical purposes. Only when high wheel load was combined with low inflation pressure the model did not give suitable results due to an overestimation of the rolling radius. Based on the presented model, a convenient Excel-application called TASCV3.0 was developed for the practice. Such a practical computer-tool supports farmers in decision making concerning the tractor configuration, oriented to save fuel during agricultural operations.

Real-time monitoring of oxidative injury of vascular endothelial cells and protective effect of quercetin using quartz crystal microbalance

The adhesion, spreading, and proliferation of human umbilical vein endothelial cell line (HUVEC-C) cells, on a gold electrode were monitored using quartz crystal microbalance (QCM) measurements. The viscodensity effect caused by the normal action of the cells led to a decrease of the resonant frequency and increase of the motional resistance. The oxidative injury of HUVEC-C cells appeared immediately with the addition of H2O2, exhibiting the decline of cellular spreading area and cell coverage on the electrode surface and resulting in inverted QCM responses. The injured extent of the cells was found to be related to the content of H2O2. It is found that 0.05mM quercetin added beforehand in the growth medium could remove completely the oxidative action of 1.0mM H2O2. Quercetin with increased dosage still exerted a partial protective effect on HUVEC-C cells against oxidative injury induced by 2.5mM H2O2. The microscope observations, electrochemical measurements, and MTT analysis validate the QCM assay results, indicating that quercetin is a valuable flavonoid anti-oxidant in the precaution and treatment for the oxidative injury of vascular endothelium. Graphical Abstract Upper part: Microscope images (×400) of 7.5×104 HUVEC-C cells adhered to the substrate at 48 h in the presence of H2O2. Middle part: Real-time Δf 0 and ΔR 1 responses to the addition of 7.5×104 HUVEC-C cells onto QCM gold electrode in the presence of H2O2 added at 24 h after the introduction of the cells. Lower part: Microscope images (×400) of 7.5×104 HUVEC-C cells adhered to the substrate at 48 h in the presence of quercetin added at 18 h and H2O2 added at 24 h after the introduction of the cells.

Single and mechanically coupled capacitive silicon nanomechanical resonators

The design, fabrication and evaluation of single and mechanically coupled capacitive silicon nanomechanical resonators is reported. The structure of resonators is fabricated on a silicon on insulator wafer and transferred to a Tempax glass substrate by anodic bonding. A finite element method simulation has been conducted to investigate the vibration modes of the resonators. Single beam resonator with a length of 21.3 μm, a width of 500 nm, a thickness of 5 μm and the capacitive gap size of about 300 nm shows a nonlinear response. The amplitude of frequency response increases as the frequency is swept upward, and then suddenly jumps to a lower value. The mechanically coupled capacitive silicon nanomechanical resonator with a number of 100 individual beams above is successfully fabricated. Some resonant peaks can be observed, which shows that most nanomechanical resonators are mechanically coupled and synchronised. A mechanical resonance at a high frequency of ∼7.2 MHz in flexural mode has been detected. A small motional resistance of 1.2 kΩ has been achieved by the mechanical coupling.

Numerical study of mixing of binary-sized particles in rotating tumblers on the effects of end-walls and size ratios

The mixing characteristics of binary-sized particles in rotating tumbler are studied by discrete element method (DEM). The cases of diameter ratios of RD=1:1, 2:1 and 3:1 under three rotating velocities ω=1.0, 2.0, 3.0 π rad/s with or without friction from front and rear walls of the tumbler are simulated. Short and long tumblers (L=0.15 and 0.3m respectively) are used with stationary or rotating end-walls. Considering the local granular concentrations of binary-sized particles, an improved information entropy function is proposed to evaluate the overall mixing degree of particles in the tumbler. Moreover, the kinetic energy and the radial distribution function are also explored to discuss the impacts of friction from front and rear walls, the size ratios and the rotating speeds on particle mixing. All the analytical results indicate that the friction from the stationary front and rear walls play a significant role in degrading the flow regime and suppressing particle mixing especially in short tumblers because of the motion resistance. When the effective contact area for end-walls is larger than the lateral wall, it may be even more important than the rotating speed for determining the mixing degree. The lengthened tumbler may attenuate the effect of end-wall frictions. The size ratios play either a positive or a negative role in influencing particle mixing, caused by the static feature of size difference and the dynamical different property inducing size segregation respectively. In addition, the rotations of end-walls may have an effect of mixing enhancement that is reverse to the stationary end-walls.

Ultraclean wafer-level vacuum-encapsulated silicon ring resonators for timing and frequency references

We present the design and development of breath-mode silicon ring resonators fabricated using a commercial pure-play microfabrication process that provides ultraclean wafer-level vacuum-encapsulation. The micromechanical resonators are fabricated in MEMS integrated design for inertial sensors process that is developed by Teledyne DALSA Semiconductor Inc. The ring resonators are designed to operate with a relatively low DC polarization voltage, starting at 5 V, while providing a high frequency-quality factor product. We study the quality of the vacuum packaging using an automated testing setup over an extended time period. We study the effect of motional resistance on the performance of MEMS resonators. The fabricated devices had a resonant frequency of 10 MHz with the quality factor exceeding 8.4×104.

Dynamic monitoring of antimicrobial resistance using magnesium zinc oxide nanostructure-modified quartz crystal microbalance

Antimicrobial resistance (AMR) is becoming a major global-health concern prompting an urgent need for highly-sensitive and rapid diagnostic technology. Traditional assays available for monitoring bacterial cultures are time-consuming and labor-intensive. We present a magnesium zinc oxide (MZO) nanostructure-modified quartz crystal microbalance (MZOnano-QCM) biosensor to dynamically monitor antimicrobial effects on E. coli and S. cerevisiae. MZO nanostructures were grown on the top electrode of a standard QCM using metal-organic chemical-vapor deposition (MOCVD). The MZO nanostructures are chosen for their multifunctionality, biocompatibility, and giant effective sensing surface. The MZO surface-wettability and morphology are controlled, offering high-sensitivity to various biological/biochemical species. MZO-nanostructures showed over 4-times greater cell viability over ZnO due to MZO releasing 4-times lower Zn2+ density in the cell medium than ZnO. The MZOnano-QCM was applied to detect the effects of ampicillin and tetracycline on sensitive and resistant strains of E.coli, as well as effects of amphotericin-B and miconazole on S. cerevisiae through the device's time-dependent frequency shift and motional resistance. The MZOnano-QCM showed 4-times more sensitivity over ZnOnano-QCM and over 10-times better than regular QCM. For comparison, the optical density at 600nm (OD600) method and the cell viability assay were employed as standard references to verify the detection results from MZOnano-QCM. In the case of S. cerevisiae, the OD600 method failed to distinguish between cytotoxic and cytostatic drug effects whereas the MZOnano-QCM was able to accurately detect the drug effects. The MZOnano-QCM biosensor provides a promising technology enabling dynamic and rapid diagnostics for antimicrobial drug development and AMR detection.

Silicone Surfactants as Potential Lubricating Substances and Bases

ABSTRACTThis article presents an assessment of the physicochemical and tribological properties of silicone polyether aqueous solutions. Raw materials used in this research were characterized by different oxyethylation and oxypropylation degrees: PEG/PPG-20/20 dimethicone, bis-PEG/PPG-20/20 dimethicone, and PEG/PPG-25/25 dimethicone. The physicochemical properties were determined by surface tension, wetting angle, and atomic force microscopy images. The tribological properties were characterized by the motion resistance changes and wear in a concentrated ball (steel)-on-disk (steel) contact. The results of physicochemical properties indicate that these compounds are surface active and characterized with good wettability of the steel surface. In addition, it was shown that under the conditions of friction they can form an adsorption layer, which lowers friction and reduces wear of friction couples. In summary, oxyethylated and oxypropylated silicone aqueous solutions, particularly at higher concentrations (60–80%), and pure compounds can be used as potential and effective lubricants.

Electromagnetic forming facilitates the transition of deformation mechanism in 5052 aluminum alloy

The identification of different deformation mechanisms in aluminum alloy under high-velocity electromagnetic forming and mechanical forming is a daunting task, due to the limitations in performing identical experimental conditions. Here, we present a special strategy to achieve electromagnetic and mechanical deformations with equivalent strain and strain rate. The intriguing finding is that the deformation mechanism of 5052 aluminum alloy is dominated by planar slip in mechanical deformation versus wavy slip in electromagnetic forming. The physical origin of the phenomenon is rationalized according to theoretical analysis coupled with finite-element-method simulation. The finite-element-method simulation presents planar and spatial force in the aluminum alloy during mechanical deformation and electromagnetic forming, respectively. The theoretical analysis reveals that under mechanical deformation with planar force, the destruction of short range cluster on the activate glide planes reduces the local resistance of dislocation motion and facilitates the planar slip. By contrast, the collective motion of dislocations in three dimensions caused by spatial force under electromagnetic forming facilitates the wavy slip that is represented by the dislocation cell structures. Our findings provide an effective method and fundamental understanding for unveiling various deformation mechanisms in aluminum alloy under electromagnetic and mechanical processing.