Axial Energy Research Articles

A novel multi-objective optimization scheme of electric turbo compressor system in hydrogen fuel cell for reducing energy consumption and axial thrust

Electric turbo compressor (ETC) can recover the exhaust energy and reduce the motor power consumption, which is the future development of the air management system for fuel cell. However, the large imbalances of axial thrust and energy between the compressor and turbine leads to low reliability and efficiency of ETC. In this study, a multi-objective optimization scheme was proposed to explore the lowest ETC axial thrust and electric power consumption. First, the coupled model including compressor, turbine and axial thrust sub-models were established in MATLAB. To verify the model, computational fluid dynamics(CFD) model were established in ANSYS CFX and experimental tests were carried out. The electric power differences between the MATLAB model and experiment is within 4.36 % and the axial thrust deviations between the MATLAB and CFD model is within 5.46 %.Then, eight geometric parameters of compressor and turbine rotors are selected as independent optimization variables. NSGA-ΙΙ multi-objective optimization algorithm was adopted to search for low axial thrust and power consumption solutions. Finally, the optimization results show that the efficiency of the compressor and turbine is increased by 6.39 % and 2.75 % at design point, respectively. The electric power consumed by the motor is reduced by 7.80 % and the axial thrust of the ETC is reduced by 18.83 %.

Axial Crushing and Energy Absorption Integrated Design of Modular Filled Double-Hat Beam Composite Structures.

In order to study the influence of modular filled and composite material forms on the axial crushing and energy absorption properties of structures, modular filled composite structures were constructed, and innovatively applied to the inner side of double-hat beam (DHB) structures in automobiles. The modular filled structures comprise hexagonal, quadrilateral, and triangular sections. By analyzing the collision performance of modular filled DHB structures, significant enhancements were observed in both the sectional characteristics and the specific Mean Crushing Force of modular filled DHBs compared to the conventional double-hat beam structure. These advancements notably improved the plastic deformation characteristics of the structures. Additionally, dynamic weightlessness experiments were conducted to validate the accuracy of the simulation model. Among the proposed schemes, namely QU-5, HE-5, and TR-5, notable improvements in crashworthiness were identified. Specifically, crashworthiness indicators increased by 32.54%, 78.9%, and 116.53%. Compared with other thin-walled structures, modular filled composite DHBs have advantages in axial crushing and energy absorption. By optimizing layout characteristics, the modular filled structures will achieve significant lightweight and energy absorption performance improvements. This work has clear reference value for automotive engineers and scholars to further explore the axial crash safety, platform modularization, and lightweight design of vehicles.

Tritium β decay and proton-proton fusion in pionless effective field theory

The Gamow-Teller and Fermi matrix elements, 〈GT〉 and 〈F〉, respectively, for tritium β decay are calculated to next-to-leading order (NLO) in pionless effective field theory in the absence of Coulomb interactions and isospin violation giving the leading order predictions 〈GT〉0=0.9807 and 〈F〉0=1. Using an experimentally determined value for the tritium β decay GT matrix element, the two-body axial current low energy constant is fixed at NLO yielding L1,A=6.01±2.08fm3 at the renormalization scale of the physical pion mass, which agrees with predictions based on naive dimensional analysis. The impact of L1,A on proton-proton fusion is also discussed. Finally, the consequences of Wigner-SU(4) spin-isospin symmetry are considered for the Gamow-Teller matrix element. Published by the American Physical Society 2024

Biomechanical comparison of two fixation methods for pediatric femoral neck fractures: an in vitro study using ovis aries lambs.

In pediatric patients, femoral neck fracture is a relatively rare injury with a high complication rate despite proper diagnosis and treatment. Fixation of femoral neck fractures is usually performed with screws placed along the neck axis. In this study, we aim to compare two different implants and methods in terms of biomechanics. Twenty-eight right-left fresh femur bones of 6-month-old male Ovis aries lambs grown on the same farm were used. Bones were randomly divided into 4 groups (n=7). In group 1, the Delbet type III femoral neck fracture model was fixed with two 4.5 mm cannulated screws, one screw crossing the physis. In group 2, two 4.5 mm cannulated screws, which did not cross the physis, were used. In group 3, Delbet type III femoral neck fracture model was fixed with a 3.5 mm proximal femoral anatomical plate and five screws, one screw crossing the physis. Finally, in group 4, Delbet type III femoral neck fracture model was fixed with one 3.5 mm proximal femoral anatomical plate and five screws that did not exceed the physis. Biomechanical tests were performed using a Zwick/Roell AllroundLine 100 kN device. While axial failure burden (F = 6.819, p<.05, d = .46) and axial stiffness (F = 3.576, p<.05, d = .30) have been found to be significantly different between the independent treatment groups, axial failure displacement (F = .622, p>.05) and axial failure energy (F = .727, p>.05) have been found not to be significant between the independent groups. The effect sizes of the axial failure load and axial stiffness variables were 0.46 and 0.30, respectively, suggesting a moderate clinical effect. The highest axial failure load was recorded in group 3, while the smallest load was recorded in group 2. Similarly, the axial stiffness level in group 3 was statistically higher than the axial stiffness measurement recorded in group 2, p<.05. Consequently, we found that the biomechanical fixation success was the highest with a 3.5 mm proximal femoral anatomical plate, a 3.5 mm locking screw crossing the physis, and five 3.5 mm screws.

Nuclear shape evolution in even-even Pd isotopic chain

The covariant density functional theory is utilized to examine the evolution of shape in even–even 96−130 Pd isotopes by using the density-dependent meson-exchange DD-ME2 and the density-dependent point-coupling DD-PC1. This research is carried out by considering the evolution of the ground-state shapes derived from calculations of the axial and triaxial potential energy surfaces. The shape transition in the palladium isotopic chain is very clearly manifested. In addition, various ground-state properties, such as binding energy, charge radius, two-neutron separation energy, and two-neutron shell gap have been calculated and have been observed to adequately match the existing experimental data. Moreover, a robust shell closure is distinctly observed at the magic neutron number N = 82.

Ant colony optimization-based method for energy-efficient cutting trajectory planning in axial robotic roadheader

The traditional cutting trajectory of the axial robotic roadheader (spiral or reciprocating) is too simple to meet the requirements of adaptive planning. We proposed a method for planning the cutting trajectory of an axial robot roadheader based on ant colony optimization, which enables the machine to automatically adapt to the rock characteristics of the tunnel face, solves the problems of high energy consumption and low cutting efficiency in existing methods. This method uses machine vision to capture the fractures in the tunnel face, construct a grid map of the fractures, and calculate the fracture parameters within each grid, including the numbers, length, width, and density, through the connected domain method. Among them, the fracture parameters is used as input and the geological strength index as output. The BPNN is established to predict GSI of the grid environment. Based on this, an improved ant colony optimization for full coverage path planning is introduced, the cutting trajectory can be planned adaptively according to the geological conditions. The method is validated on a axial robotic roadheader, demonstrating its ability to adaptively plan cutting paths based on the geological conditions of the tunnel face. Compared to traditional methods, it reduces axial robotic roadheader energy consumption. This research enhances the intelligence level of coal mining robots, reduces energy consumption, and increases equipment lifespan.

Effects of Steel Fiber Content on Compressive Properties and Constitutive Relation of Ultra-High Performance Shotcrete (UHPSC)

Shotcrete is widely used in civil engineering as a supporting structure. In this paper, the compressive behavior of ultra-high-performance shotcrete (UHPSC) with different steel fiber content by volume (0, 0.5%, 0.75%, 1%, 1.25%, 1.5%) was investigated. The results showed that the failure pattern of UHPSC was changed from brittle failure to ductile failure with the increase in steel fiber content. The compressive strength, peak strain and compressive toughness of UHPSC increased with the increase in steel fiber content, but the elastic modulus and Poisson’s ratio did not change significantly. With content of 1.5% steel fibers, its axial compressive strength, peak strain and compressive strain energy were 122.7 MPa, 3749 με and 0.269 MPa, respectively, increased by 14%, 23.5% and 55.5% compared with those without steel fiber. The peak strain and compressive toughness were higher than that of ultra-high-performance concrete (UHPC), while the elastic modulus of UHPSC was lower than that of UHPC. Based on the experimental data, the relationship between compressive strength, peak strain, compressive toughness and the change in the characteristic value of steel fiber content (λf) were revealed. The uniaxial compressive constitutive model of UHPSC with different steel fiber content was established and reflected the change rule of the shape parameter of α (constitutive model ascending section) and β (constitutive model descending section) with λf. The experimental results were in good agreement with the model calculation results, which can provide theoretical support for the structural design of UHPSC.

The axially-loaded behaviours of Schwarz Primitive (SP)-based structures: An experimental and DEM study

This study delves into the axial responses of Schwarz Primitive (SP) structures. Emphasising on bearing capacity, force distribution, cracking phenomena, load-displacement curve and energy absorption. Discrete element method (DEM) is adopted to analyse the axial load-bearing behaviour and fracture mechanics of Main SP and Secondary SP structures under various unit cell configurations after validated by experimental tests. The results indicates that despite sharing the same 1/8th cell structure, the axially-loaded behaviours of the Main SP and Secondary SP structures are not identical, particularly in scenarios involving a large unit cell size and a small number of unit cells. The Main SP structures display an axial load-bearing behaviour that is largely unaffected by variations in the number of unit cells along the x and y axes, while Secondary SP structures show a more pronounced improvement in average strength and energy absorption capacity when the number of unit cells increases. Main SP structures offer superior axial load-bearing capabilities and energy absorption efficiency, which is a significant consideration for their application in scenarios demanding high structural integrity. This distinction underlines the importance of tailored design and selection of SP configurations based on specific engineering requirements.

Axial crushing responses and energy absorption characteristics of aluminum honeycombs filled with graphene oxide modified rigid polyurethane foam

This study aims to explore the potential application of hollow glass beads (HGB) compounded with graphene oxide (GO, HGB@GO) to improve the mechanical properties of rigid polyurethane foam (RPUF). This HGB@GO/RPUF composite is considered a potential filler for reinforcing aluminum honeycomb (AH). A characterization of the chemical structure and surface morphology of HGB@GO was conducted, as well as the analysis of its effect on the compression properties of the foam. The compressive strength of HGB@GO/RPUF (4 wt. %) is 146.17% higher than that of pure RPUF. This study also compared the deformation modes of AH and foam-filled honeycomb (F-AH) structure under axial crushing. The interaction effects between the foam and AH were also analyzed. The results indicated that the RPUF improves the compressive capacity and deformation stability of the AH through its good compression properties and interaction with the aluminum foil. The use of HGB@GO/RPUF further enhances the energy absorption characteristics of the F-AH. In comparison with the pure RPUF-AH, the total and specific energy absorption of the HGB@GO/RPUF (4 wt. %)-AH increase by 74.65% and 44.98%, respectively. This work demonstrates that the prepared HGB@GO can enhance the mechanical properties of RPUF, and HGB@GO/RPUF-AH is expected to be a desirable energy-absorbing device.

A numerical study on thickness of rear under-ride protection in case pick-up to semi-trailer full rear impact

In the global supply chain, large trucks, tractors, and semitrailers are essential as the final step in this complex network. However, they have many potential dangers because the gaps from the semi-trailer's floor to the road surface are high, so small cars easily get underride. To solve this issue, some regulations have required the installation of additional protection devices on the front, sides, and rear where these gaps exist, for example, FMVSS 223, 224 of the US, or UNECE R58 of Europe. Using LS-DYNA software and trailer and pick-up models from proven sources to set up a collision simulation, then proceed to change the thickness of the rear underride protection device to assess the effect. The collision was designed with 55.8 km/h of pick-up and a stationary trailer. The effect of change thickness on axial displacement and energy changes is presented. The study results are expected to be helpful for the structural design and safety assessment of various structures including marine vehicles and cars against collisions. Keywords: Rear under-ride, protection device, design, truck, semi-trailer

Critical loss of primary implant stability in osteosynthesis locking screws under cyclic overloading

Primary implant stability, which refers to the stability of the implant during the initial healing period is a crucial factor in determining the long-term success of the implant and lays the foundation for secondary implant stability achieved through osseointegration. Factors affecting primary stability include implant design, surgical technique, and patient-specific factors like bone quality and morphology. In vivo, the cyclic nature of anatomical loading puts osteosynthesis locking screws under dynamic loads, which can lead to the formation of micro cracks and defects that slowly degrade the mechanical connection between the bone and screw, thus compromising the initial stability and secondary stability of the implant. Monotonic quasi-static loading used for testing the holding capacity of implanted screws is not well suited to capture this behavior since it cannot capture the progressive deterioration of peri‑implant bone at small displacements. In order to address this issue, this study aims to determine a critical point of loss of primary implant stability in osteosynthesis locking screws under cyclic overloading by investigating the evolution of damage, dissipated energy, and permanent deformation. A custom-made test setup was used to test implanted 2.5 mm locking screws under cyclic overloading test. For each loading cycle, maximum forces and displacement were recorded as well as initial and final cycle displacements and used to calculate damage and energy dissipation evolution. The results of this study demonstrate that for axial, shear, and mixed loading significant damage and energy dissipation can be observed at approximately 20 % of the failure force. Additionally, at this load level, permanent deformations on the screw-bone interface were found to be in the range of 50 to 150 mm which promotes osseointegration and secondary implant stability. This research can assist surgeons in making informed preoperative decisions by providing a better understanding of the critical point of loss of primary implant stability, thus improving the long-term success of the implant and overall patient satisfaction.

Rapid exchange cooling with trapped ions

The trapped-ion quantum charge-coupled device (QCCD) architecture is a leading candidate for advanced quantum information processing. In current QCCD implementations, imperfect ion transport and anomalous heating can excite ion motion during a calculation. To counteract this, intermediate cooling is necessary to maintain high-fidelity gate performance. Cooling the computational ions sympathetically with ions of another species, a commonly employed strategy, creates a significant runtime bottleneck. Here, we demonstrate a different approach we call exchange cooling. Unlike sympathetic cooling, exchange cooling does not require trapping two different atomic species. The protocol introduces a bank of “coolant" ions which are repeatedly laser cooled. A computational ion can then be cooled by transporting a coolant ion into its proximity. We test this concept experimentally with two 40Ca+ ions, executing the necessary transport in 107 μs, an order of magnitude faster than typical sympathetic cooling durations. We remove over 96%, and as many as 102(5) quanta, of axial motional energy from the computational ion. We verify that re-cooling the coolant ion does not decohere the computational ion. This approach validates the feasibility of a single-species QCCD processor, capable of fast quantum simulation and computation.

Axial crushing and energy absorption of graded hierarchical hexagonal tubes

The concept of both hierarchy and gradient are incorporated into thin-walled hexagonal tubes for a configuration with optimum crashworthiness and energy absorption. Graded hierarchical hexagonal (GHH) tubes are developed by replacing the corners of an original hexagonal tube with a series of micro hexagonal cells. The total net cross-sectional area as well as the mass are kept the same for all the GHH tubes. The axial crushing behavior of the GHH tubes is investigated in terms of deformation modes, crushing forces and energy absorption. Theoretical solutions are also derived to predict the mean crushing forces (MCFs) of the GHH tubes. Two deformation modes have been identified, a locally layer-by-layer folding deformation (Mode-L) and a globally buckling-like deformation (Mode-G). The hierarchical and graded parameters have significant but quite different influences on the crushing behavior of GHH tubes. The MCF and the specific energy absorption (SEA) can be significantly improved with reasonably hierarchical and graded arrangements, while the initial peak force (PF) remains almost constant.

Electron plasma diagnostics in ELTRAP by electron cyclotron resonance heating method.

Electron cyclotron resonance heating method of Particle-in-Cell code was used to analyze heating phenomena, axial kinetic energy, and self-consistent electric field of confined electron plasma in ELTRAP device by hydrogen and helium background gases. The electromagnetic simulations were performed at a constant power of 3.8 V for different RF drives (0.5 GHz- 8 GHz), as well as for 1 GHz constant frequency at these varying amplitudes (1 V-3.8 V). The impacts of axial and radial temperatures were found maximum at 1.8 V and 5 GHz as compared to other amplitudes and frequencies for both background gases. These effects are higher at varying radio frequencies due to more ionization and secondary electrons production and maximum recorded radial temperature for hydrogen background gas was 170.41 eV. The axial kinetic energy impacts were found more effective in the outer radial part (between 0.03 and 0.04 meters) of the ELTRAP device due to applied VRF through C8 electrode. The self-consistent electric field was found higher for helium background gas at 5 GHz RF than other amplitudes and radio frequencies. The excitation and ionization rates were found to be higher along the radial direction (r-axis) than the axial direction (z-axis) in helium background gas as compared to hydrogen background gas. The current studies are advantageous for nuclear physics applications, beam physics, microelectronics, coherent radiation devices and also in magnetrons.

Comparative predictions of turbulent non-isothermal flow of a viscoplastic fluid with yield stress

RANS simulation of turbulent non-isothermal flow in a pipe by transition of Newtonian fluid into a viscoplastic non-Newtonian fluid is carried out. Carrier phase turbulence was modeled using two-equation isotropic k‒ε˜ – model and Reynolds stress transport model. Results of calculations of Newtonian and non-Newtonian power-law fluids were compared with data of DNS calculations of other authors. Comparisons with data from other works for isothermal Schwedoff-Bingham fluid were performed in this work using k‒ε˜ – model. Satisfactory agreement was obtained with data from other studies for the axial averaged velocity and turbulent kinetic energy radial profiles (the difference is up to 15 %). Reynolds stress transport model showed significant anisotropy between streamwise and transverse velocity fluctuations (up to several times) and good agreement with DNS results of other authors. Averaged and pulsation profiles express the indicated transformation of the non-isothermal turbulent flow.

Axial and radial reversibility and energy absorption behaviors of braided shape memory composite thin-walled tubes

Braided shape memory polymer composites (SMPCs), which integrate braided structures with shape memory polymers, are well-known for their superior mechanical properties, reversible deformation, and recovery capabilities. This study focused on exploring the reusable energy absorption capacity of intelligent braided SMPC tubes. The effects of braiding structure on compression modes, mechanical properties, energy absorption, shape memory performance, and repeatability under axial and radial compression have been comprehensively investigated. The results show that SMPC tubes have a shape recovery ratio exceeding 94 % after four cycles. As the number of compressions increased, both the mechanical and energy absorption properties decreased, particularly during the first compression. Higher energy absorption capacity has been observed in SMPC tubes with larger braiding angles, up to 32.51 J, 2.3 times that of pure TPU tubes. These findings offer potential approaches for the development of high-performance reusable protective devices and lightweight intelligent structures.

Evaluation of increase in loss tangent from longitudinal vibration of wood log by considering apparent density difference between sapwood and heartwood caused by moisture content

This study confirmed that the loss tangent (or tangent loss, tan δ) obtained from the longitudinal vibration of a wood log increases with the apparent density difference between sapwood and heartwood, owing to moisture content difference. The reason for this was estimated to be the shear stress occurring when the longitudinal vibration is excited from the calculation of the longitudinal vibration equation for a cylindrical model with different sapwood and heartwood densities. According to the measurement of the vibrational properties of 35 sugi (Cryptomeria japonica) logs with large moisture content variation in the sapwood and heartwood, the tan δ for longitudinal vibration increased compared with that for flexural vibration when the apparent sapwood density exceeded apparent heartwood density, whereas the difference in the specific dynamic Young’s modulus (E/ρ) was small. To discover why tan δ increases, both the axial and shear strain energy were calculated from the numerical solution of the longitudinal vibration of a cylindrical model by only considering the apparent density difference between sapwood and heartwood. It was found that the shear strain energy increases with the apparent density difference. Because it is known from previous studies that tan δ from the shear strain (tan δS) is larger than that from the axial strain (tan δA), this study concluded that tan δ increases with the apparent density difference. The ratio of increase of tan δ calculated by the model adequately explaange of the measured tan δ caused by the longitudinal vibration of a sugi log.

Exploring the mechanism of axial ion energy acquisition and loss in an magnetoplasmadynamic thruster plume

In order to investigate the mechanism of axial ion energy acquisition and loss in an applied-field magnetoplasmadynamic thruster (AF-MPDT) plume plasma, a 10 kW level MPDT was tested using a Gauss meter, a Langmuir probe, a Faraday probe, a retarding potential analyzer (RPA) and a thrust target stand. Axial ion energy (Eiz) and axial Lorentz force density (Fz) distributions are obtained and interconnected. In the R direction, a local peak in Eiz exists as a result of the presence of maximum Fz in proximity. This localized Fz surge is instigated by the diamagnetic current, a consequence of the abrupt density reduction near the beam edge. In the Z direction, Eiz first increases to a maximum and subsequently decreases. The increase is due to the dominant Fz in ion acceleration in the vicinity of the thruster exit. Further downstream, the Fz decreased and the effect of charge-exchange collisions became apparent, leading to the decrease of Eiz.

Design of parabolic conic gas cyclones for coarse particle classification: A CFD study with Response Surface Methodology

Gas cyclones have traditionally been used as particle separators to remove dust from gas streams, with the goal of achieving a dust-free gas flow at the exit pipe and recovering particles to the dust outlet. Typically, the particle size for removal to the dust outlet is less than 1 μm. However, gas cyclones can also be targeted for particle classification rather than particle removal. In this study, the effect of the shape of the curved conical wall, specifically the parabolic concave and convex conic designs, on particle classification in a 31 mm diameter gas cyclone was evaluated using Computational Fluid Dynamics (CFD). The CFD model predictions for standard small-scale gas cyclones were validated using experimental data available in the literature for various inlet flow rates. The curvature of the conical wall varied from convex to concave, resulting in the observation of sharper and coarser cut sizes for the parabolic conic designs. The cut size increases to 4.91 μm for the concave design at a flow rate of 30 liters per minute, compared to 3.38 μm and 2.65 μm for the convex and standard design cyclones, respectively. The axial, tangential, pressure, and turbulent kinetic energy profiles were used to provide an explanation for the observed results. The interaction effects between the parameters were explored using the Response Surface Methodology. Further, Monte Carlo simulations are performed to observe the trends in predictions by exploring the design space.

Mesoscale study on the mechanical properties and energy absorption characteristics of aluminum foam-filled CFRP tubes under axial compression

This study investigates the axial compression mechanics and energy absorption characteristics of aluminum foam-filled carbon fiber-reinforced polymer (CFRP) tubes from both experimental and simulation perspectives. Quasi-static compression experiments of aluminum foam specimens, single CFRP tubes and aluminum foam-filled CFRP tubes are carried out. Based on the experimental results, compression simulations are conducted to investigate the structural deformation and the energy absorption characteristics of aluminum foam-filled CFRP tubes at the mesoscale. The effects of structural parameters on the compression mechanics and energy absorption characteristics of aluminum foam-filled CFRP tubes are explored.