Uniform Force Research Articles

Challenging the Narrative

Abstract This article delves into the complex issues surrounding majoritarian fundamentalism and minority insecurity in contemporary India. It carefully examines the various ways in which majoritarian influence manifests in Indian society, including electoral trends, legislative decisions, and public discourse data. Rather than presenting a simplistic view of majoritarianism as a uniform and unchanging force, the article argues that it is a contested terrain shaped by historical, socio-political, and economic factors. The analysis highlights instances where majoritarian policies have been challenged and minority rights upheld, demonstrating the resilience of democratic principles and social movements. The article also critiques sensationalist media portrayals that perpetuate stereotypes and divisive narratives, advocating for responsible journalism that fosters understanding and empathy across communities. Ultimately, the article emphasizes the importance of inclusive leadership, dialogue, and collaboration in building cohesive societies, drawing on successful inter-community harmony and grassroots cooperation models. It underscores the need for nuanced discourse and evidence-based analysis to address systemic injustices and promote social cohesion in India.

Climate response to interhemispheric differences in radiative forcing governed by shortwave cloud feedbacks

Abstract Understanding the climate response to interhemispheric differences in imposed radiative forcing is crucial for solar radiative modification (SRM) investigations. While previous studies have shown that climate sensitivity to solar insolation changes imposed in the Northern (NH) versus the Southern Hemisphere (SH) is different, the underlying mechanisms remain unclear. In this study, we investigate the climate response to three different radiative forcing scenarios: globally uniform radiative forcing, radiative forcing imposed only in the NH, and radiative forcing confined only to the SH. We find that the climate sensitivity is larger when forcing is imposed only in the SH. To explain the mechanisms for this, we estimate climate feedbacks using the radiative kernel approach. We find that albedo and Planck feedbacks are insensitive to hemisphere of forcing, and the larger climate sensitivity to the southern hemispheric radiative forcing is primarily due to differences in shortwave cloud feedbacks. Additionally, we examine impacts of interhemispheric differences in radiative forcing on tropical circulation, planetary albedo, and land/sea warming contrast. Our results clearly demonstrate how the intertropical convergence zone moves into the hemisphere where the radiative forcing is larger without maintaining a symmetric planetary albedo. Overall, our study provides insights into climate system responses to interhemispheric differences in radiative forcing caused by forcing agents such as aerosols from volcanic eruptions and human activities, and land cover changes, in addition to solar geoengineering.

Biosorption of cypermethrin from aqueous solutions by Pediococcus acidilactici: kinetics, isotherms, and mechanisms.

Pediococcus acidilactici is an effective adsorbent for removing of pyrethroid insecticides. This study investigated the biosorption characteristics and mechanisms of P. acidilactici D15 using adsorption measurement, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Isotherm and kinetic models were used to analyze the biosorption process. The Langmuir isotherm model best described the cypermethrin biosorption process, with the maximum adsorption capacity of P. acidilactici D15 being 21.404 mg/g. The biosorption appeared to involve monolayer coverage with uniform forces. The pseudo-second-order model also fits well. The rate-controlling steps involved intraparticle diffusion, film diffusion and chemosorption. The main cellular components involved in cypermethrin biosorption were exopolysaccharides, spheroplast, and cell wall, especially peptidoglycan. The functional groups (-OH, -NH, -CH3, -CH2, -CH, -CONH-, -CO, and -C-O-C-) from proteins, polysaccharides, and peptidoglycan on the cell surface likely played a role in binding cypermethrin. Additionally, P. acidilactici D15 effectively reduced cypermethrin in pickle wastewater. These findings suggest that P. acidilactici D15 could be a potential agent for reducing pesticide residues, laying the groundwork for treating pickle wastewater containing such pesticide residues. © 2024 Society of Chemical Industry.

Localized topological states beyond Fano resonances via counter-propagating wave mode conversion in piezoelectric microelectromechanical devices

A variety of scientific fields like proteomics and spintronics have created a new demand for on-chip devices capable of sensing parameters localized within a few tens of micrometers. Nano and microelectromechanical systems (NEMS/MEMS) are extensively employed for monitoring parameters that exert uniform forces over hundreds of micrometers or more, such as acceleration, pressure, and magnetic fields. However, they can show significantly degraded sensing performance when targeting more localized parameters, like the mass of a single cell. To address this challenge, we present a MEMS device that leverages the destructive interference of two topological radiofrequency (RF) counter-propagating wave modes along a piezoelectric Aluminum Scandium Nitride (AlScN) Su-Schrieffer-Heeger (SSH) interface. The reported MEMS device opens up opportunities for further purposes, including achieving more stable frequency sources for communication and timing applications.

Deep subwavelength sound absorption by a buckling plate resonator

Conventional sound-absorbing materials face great difficulties in achieving deep subwavelength broadband sound absorption due to the causal constraint on the minimum thickness. A buckling plate resonator is proposed to alleviate the causal constraint on the thickness of sound-absorbing materials. The resonator consists of a back cavity sealed by an elastic circular thin plate. When the plate is subjected to a uniform in-plane compressive force up to its critical load, it buckles and behaves as a negative stiffness spring. The positive stiffness of the back cavity is counteracted by the negative stiffness of the buckling plate, resulting in resonance absorption at the deep subwavelength scale. The sound absorption performance of the buckling plate resonator under different in-plane loads was measured in an impedance tube. Quasi-perfect sound absorption was observed in a buckling plate resonator with a thickness less than 1% of the wavelength corresponding to the resonance frequency. This work provides a solution for the design of ultra-thin broadband sound absorbers.

Tightening and anti-loosening performance of spring washer connecting bolts

This paper investigates the tightening and anti-loosening performance of phosphated spring washers (i.e., PSW) and galvanized spring washers (i.e., GSW), considering three torques and comparing them with galvanized flat washers (i.e., GFW). Subsequently, a finite element model of the spring washer connecting bolt was established and validated, further investigating the force performance of the spring washer and the stress distribution in the thread area. Finally, a quantitative evaluation method for the anti-loosening performance of spring washers was proposed. The results show that the preload of GSW is maximum after the nut is tightened, and the loss of preload can be supplied by the flattened spring washer. At the same time, the inner ring of the spring washer is sticking, while the outer ring is sliding. Similarly, the contact pressure of the washer decreases radially. During the lateral vibration process, the decrease curve of preload consists of three stages: initial stage, stable stage, and loosening rotation stage. Specifically, GSW has the best anti-loosening performance, because the wear of the zinc layer increases friction. More importantly, the spring washer compensates for the gap between the nut contact surface during transverse vibration, ensuring uniform force distribution in the threaded area and effectively improving the anti-loosening performance.

Novel multi-layer field shaper in electromagnetic manufacturing process technology of tube joining for uniform deformation

Electromagnetic joining technology is widely utilized in assembling tubular components due to its ability to exert uniform magnetic pressure. To augment this pressure, a field shaper structure has been introduced. However, the conventional design may impair the uniformity of deformation, particularly at the seam. This study presents a novel multi-layer field shaper (MLFS) to enhance deformation uniformity. The performance of the MLFS was evaluated and optimized through experimental trials and simulation analysis. The results showed that MLFS achieved a 300 % increase in minimum deformation with a 56 % reduction in the aspect ratio, demonstrating that our design effectively balances efficiency with deformation uniformity. The magnetic cubic decay formula could fit the simulation data well with R2 higher than 0.999. MLFS was found to enhance uniformity by creating a more even magnetic field that decreased the curvature near the plastic hinge. Compared to altering the interlayer thickness, adjusting the interlayer angle can further enhance uniformity. When the rotation angle is 60°, the radius range can be further reduced by 32.5 %, 39.0 %, and 12.2 % at energy levels of 27 kJ, 30 kJ, and 33 kJ, respectively. The above results indicate that by designing and optimizing MLFS, sufficiently large and uniform electromagnetic forces were obtained.

Dynamic response analysis of submerged floating tunnel after anchor cables forces adjustment under impact load

Submerged Floating Tunnel (SFT) is a new type of cable-supported structural system for straight crossings. In this study, the initial state of the SFT was optimized based on the existing SFT cable-force adjustment method (relatively uniform cable forces, minimizing the support reaction forces at the abutment section). The responses of the SFT under static and seismic conditions before and after cable-force adjustment were compared, further verifying the optimization effect of the cable-force adjustment method on the structural performance of the SFT. In addition, a theoretical model (flexible support model) of the anchor cables was proposed to calculate the displacement after impact by sunken ships. A finite element model of the SFT was established using ABAQUS to prove the accuracy of the flexible boundary model. In addition, the flexible support stiffnesses of anchor cables at different positions were determined based on the finite element model. Finally, the SFT after the cable-force adjustment was analyzed to study the response patterns of the anchor cables at different positions under an impact load. The results demonstrate that a correlation between the distribution pattern of the flexible boundary stiffnesses of anchor cables and the regulation of the responses of the anchor cables to impact load.

Underestimates of Orographic Precipitation in Idealized Simulations. Part I: Evidence from Unidirectional Warm-Sector Environments

Abstract Heavy precipitation in midlatitude mountain ranges is largely driven by the episodic passage of weather systems. Previous studies have shown a high correlation between the integrated vapor transport (IVT) in the airstream striking a mountain and the precipitation rate. Using data collected during the Olympic Mountain Experiment (OLYMPEX) project from a pair of sounding stations and a dense precipitation network, we further document the tight relation between IVT and precipitation rate and obtain results consistent with earlier work. We also survey previous studies that simulated orographic precipitation forced by unidirectional shear flows. Some of these simulations were performed using models that produce reasonably accurate rainfall totals in nested simulations of actual events driven by large-scale flows. Nevertheless, the increase in precipitation with IVT in all the simulations with unidirectional upstream flows is far lower than what would be expected based on the observationally derived correlation between IVT and precipitation rate. As a first step toward explaining this discrepancy, we conduct idealized simulations of a midlatitude cyclone striking a north–south ridge. The relationship between IVT and rainfall rate in this “Cyc+Mtn” simulation matches that which would be expected from observations. In contrast, when the conditions upstream of the ridge in the Cyc+Mtn case were used as upstream forcing in a horizontally uniform unidirectional flow with the same IVT over the same mountain ridge, far less precipitation was produced. These idealized simulations will, therefore, be used to study the discrepancy in rainfall between simulations driven by unidirectional shear flows and observations in a companion paper. Significance Statement Idealized simulations of orographic precipitation using horizontally uniform environmental forcing fail to capture the observed relationship between integrated water vapor flux impinging on the mountain and the precipitation rate. This suggests we need to improve the design of such idealized simulations.

Development and Investigation of a Grasping Analysis System with Two-Axis Force Sensors at Each of the 16 Points on the Object Surface for a Hardware-Based FinRay-Type Soft Gripper.

The FinRay soft gripper achieves passive enveloping grasping through its functional flexible structure, adapting to the contact configuration of the object to be grasped. However, variations in beam position and thickness lead to different behaviors, making it important to research the relationship between structure and force. Conventional research using FEM simulations has tested various virtual FinRay models but replicating phenomena such as buckling and slipping has been challenging. While hardware-based methods that involve installing sensors on the gripper and the object to analyze their states have been attempted, no studies have focused on the tangential contact force related to slipping. Therefore, we developed a 16-way object contact force measurement device incorporating two-axis force sensors into each of the 16 segmented objects and compared the normal and tangential components of the enveloping grasping force of the FinRay soft gripper under two types of contact friction conditions. In the first experiment, the proposed device was compared with a device containing a six-axis force sensor in one segmented object, confirming that the proposed device has no issues with measurement performance. In the second experiment, comparisons of the proposed device were made under various conditions: two contact friction states, three object contact positions, and two object motion states. The results demonstrated that the proposed device could decompose and analyze the grasping force into its normal and tangential components for each segmented object. Moreover, low friction conditions result in a wide contact area with lower tangential frictional force and a uniform normal pushing force, achieving effective enveloping grasping.

A new model with uniform damping force for frictionless impacts with non-permanent deformation at the time of separation

A new model with uniform damping force for frictionless impacts with non-permanent deformation at the time of separation

Autonomous dynamics of two-dimensional insulating domain with superclimbing edges

Superclimbing dynamics is the signature feature of transverse quantum fluids describing wide superfluid one-dimensional interfaces and/or edges with negligible Peierls barrier. Using Lagrangian formalism, we show how the essence of the superclimb phenomenon—dynamic conjugation of the fields of the superfluid phase and geometric shape—clearly manifests itself via characteristic modes of autonomous motion of the insulating domain (“droplet”) with superclimbing edges. In the translation invariant case and in the absence of supercurrent along the edge, the droplet demonstrates ballistic motion with the velocity-dependent shape and zero bulk currents. In an isotropic trapping potential, the droplet features a doubly degenerate sloshing mode. The period of the ground-state evolution of the superfluid phase (dictating the frequency of the AC Josephson effect) is sensitive to the geometry of the droplet. The supercurrent along the edge dramatically changes the droplet dynamics: The motion acquires features resembling that of a two-dimensional charged particle interacting with a perpendicular magnetic field. In a linear external potential (uniform force field), the state with a supercurrent demonstrates a spectacular gyroscopic effect—uniform motion in the perpendicular to the force direction. Published by the American Physical Society 2024

Effects of different loading on the bifurcation of annular elastic rods: Theory vs. experiments

The bifurcation problem of a circular Euler–Bernoulli rod subject to a uniform radial force distribution is investigated under three distinct loading conditions: (i.) hydrostatic pressure, (ii.) centrally-directed, and (iii.) dead load. Previous studies on this apparently ‘familiar’ structural problem have yielded controversial results, necessitating a comprehensive clarification. This study shows that results previously labelled as ‘correct’ or ‘wrong’ simply refer to different external constraints, whose presence becomes necessary only for the two latter loads, (ii.) and (iii.). Moreover, the paper presents the first experimental realization of a circular rod subjected to centrally-directed loads. The experimental findings align with the theoretical predictions and show the exploitation of a new type of load acting on a continuous structural element. The feasibility of this load is demonstrated through the use of inextensible cables and opens the way to applications in flexible robotics when cables are used for actuation.

Out-of-plane interactive behavior and design of novel T-hooked buckling-restrained steel plate shear walls

To eliminate the use of a large number of connecting bolts for the cover panels in conventional buckling-restrained steel plate shear walls (BRSPSWs), T-hooked BRSPSW was proposed by using T-sectional stiffeners for restraining the out-of-plane deformation of the cover panels. With larger-sized flexural cover panels that provide confinement effects to the infilled steel plate, the out-of-plane interactive behavior between the infilled steel plate and each cover panel is greatly concerned for safe designs of the T-hooked BRSPSW. In this paper, a refined finite element (FE) model was established for evaluating the out-of-plane restraining effects in the T-hooked BRSPSW. The key parameters affecting the high-order buckling modes of the infilled steel plate were analyzed. The average spacing between adjacent buckling half-waves varied from 0.15 to 0.7 times the height of the steel sub-plate across common parameter ranges. Furthermore, a formula that estimates the total extrusion force produced by the buckled steel plate was corrected. By simplifying the cover panels into one-way flexural plates under uniform force, a flexural moment amplification coefficient in the range of 1.11 − 9.74 was defined to consider the difference between the actual strip-shaped interaction forces and the simplified model. Finally, a formula to calculate the bending moment of cover panels was proposed to safely design the T-hooked BRSPSWs.

Analysis from the Functional Viewpoint of a Single-Cylinder Horizontal Steam Engine with a Crosshead Trunk Guide through Engineering Graphics

This paper explores a historical innovation created by Henry Muncaster: a stationary steam engine featuring a single-cylinder horizontal design with a crosshead trunk guide. Through the application of engineering graphics techniques, we have elucidated the functioning of this invention by developing a 3D CAD model based on the original drawings published in Model Engineer magazine in 1957. However, the geometric modeling process faced challenges due to missing and erroneous dimensions for several components. Consequently, dimensional, geometric, and movement constraints were applied to ensure the coherence and functionality of the 3D CAD model, alongside conducting an interference analysis. Ultimately, the proper alignment of the cylinder and crosshead was ascertained, which is crucial for maintaining uniform forces and motions within the steam engine. This alignment is pivotal for achieving balanced operation, minimizing vibrations, and enhancing the overall efficiency of the invention.

Curved carbon-plated shoe may further reduce forefoot loads compared to flat plate during running

Using a curved carbon-fiber plate (CFP) in running shoes may offer notable performance benefit over flat plates, yet there is a lack of research exploring the influence of CFP geometry on internal foot loading during running. The objective of this study was to investigate the effects of CFP mechanical characteristics on forefoot biomechanics in terms of plantar pressure, bone stress distribution, and contact force transmission during a simulated impact peak moment in forefoot strike running. We employed a finite element model of the foot-shoe system, wherein various CFP configurations, including three stiffnesses (stiff, stiffer, and stiffest) and two shapes (flat plate (FCFP) and curved plate (CCFP)), were integrated into the shoe sole. Comparing the shoes with no CFP (NCFP) to those with CFP, we consistently observed a reduction in peak forefoot plantar pressure with increasing CFP stiffness. This decrease in pressure was even more notable in a CCFP demonstrating a further reduction in peak pressure ranging from 5.51 to 12.62%, compared to FCFP models. Both FCFP and CCFP designs had a negligible impact on reducing the maximum stress experienced by the 2nd and 3rd metatarsals. However, they greatly influenced the stress distribution in other metatarsal bones. These CFP designs seem to optimize the load transfer pathway, enabling a more uniform force transmission by mainly reducing contact force on the medial columns (the first three rays, measuring 0.333 times body weight for FCFP and 0.335 for CCFP in stiffest condition, compared to 0.373 in NCFP). We concluded that employing a curved CFP in running shoes could be more beneficial from an injury prevention perspective by inducing less peak pressure under the metatarsal heads while not worsening their stress state compared to flat plates.

Load Identification in Steel Structural Systems Using Machine Learning Elements: Uniform Length Loads and Point Forces

Actual load identification is a most important task solved in the course of (1) engineering inspections of steel structures, (2) the design of systems rising or restoring the bearing capacity of damaged structural frames, and (3) structural health monitoring. Actual load values are used to determine the stress–strain state (SSS) of a structure and accomplish various engineering objectives. Load identification can involve some uncertainty and require soft computing techniques. Towards this end, the article presents an integrated method combining basic provisions of structural mechanics, machine learning, and artificial neural networks. This method involves decomposing structures into primitives, using machine learning data to make projections, and assembling structures to make final projections for steel frame structures subjected to elastic strain. Final projections serve to identify parameters of point forces and loads distributed along the length of rods. The process of identification means checking the difference between (1) weight coefficient matrices applied to unit loads and (2) actual loads standardized using maximum load values. Cases of neural network training and parameters identification are provided for simple beams. The aim of this research is to enhance the reliability and durability of steel structures by predicting consequences of unfavorable load, including emergency impacts. The novelty of this study lies in the co-use of artificial intelligence elements and structural mechanics methods to predict load parameters using actual displacement curves of structures. This novel approach will enable engineering inspection teams to predict unfavorable load peaks, prevent emergency situations, and identify actual causes of emergencies triggered by excessive loading.

Investigating the properties of mixed finite elements

The paper considers quadrature-cubic interpolation in problems of restoration of functions of two arguments. The properties of the most common finite elements Q12 (Lagrange version) and Q10 (Serendipity version) are investigated as finite elements. For more than fifty years, researchers of the finite element method have known the procedure of converting the Lagrangian model to the serendipity model. But, as is known, not all results when using this procedure satisfy users, especially proponents of physical interpretation. We are talking about the magnitude of the nodal loads of the uniform mass force of the serendipity finite element. Thus, if we consider the finite element Q10, it receives the physical inadequacy of the "spectrum" as an inheritance from the "parent" pair of Lagrangian finite elements Q8 and Q12. In Pascal's scheme, there is also a hidden connection between the finite element Q10 and the finite element Lagrangian Q12. The analysis of the inherited properties suggests that it is fundamentally possible for a Q10 substitute-base to exist in nature with the same local and integral characteristics. It turns out that the search for such a base goes beyond the capabilities of traditional modeling methods. An alternative substitute-basis Q10 was found by nonmatrix condensation of the prototype of element Q10, i.e., by using the Lagrangian model Q12. The universal nature of the non-matrix transformation of Q12 into Q10 opens up the possibility of designing a model series of mixed finite elements with physically adequate spectra of nodal loads.

Combined effects of rotating and thermal radiation on heat and mass transfer of MHD flow in converging and diverging channels

ABSTRACT Current study deals with influence of rotating and thermal radiative fluxing on fluid’s thermal, hydrodynamic, and concentration behavior flowing between two nonparallel walls in existence of uniform magnetized force. The modeling is based on nonlinear partial differential equations (PDEs) such as continuity, momentum, temperature, and concentricity equations. These equations are converted into a system of nonlinear ordinary differential equations (ODEs) utilizing similarity transformations. Analytical solution has been constructed using the Differential Transform Method (DTM). The present results are compared to results obtained by the HAM package and by the numerical procedure (RKF-45) for validation. The impacts of active variables like the rotational factor, Hartmann, Schmidt numbers, and thermal radiation parameter, are investigated on the rapidity, temperature, and concentricity profiles. Moreover, frictional force factor, Nusselt, and Sherwood quantities. It is found that speed and concentricity of the fluid flow increase with the growth of Hartmann number, whereas a reverse behaviour is observed for thermal distribution. Results obtained also reveal an improvement in frictional force factor, Nusselt and Sherwood numbers with the enhancement of Reα parameter. It is found that an increase in the rotational parameter Ro and the radiation factor Rd leads to a decrease in the Nusselt number.

Automated Grasp Planning and Finger Design Space Search Using Multiple Grasp Quality Measures

As the industry shifts to automated manufacturing and the assembly of parts in smaller batches, there is a clear need for an efficient design of grippers. This paper presents a method for automated grasp planning and finger design for multiple parts using four grasp quality measures that capture the following important requirements for grasping: (i) uniform contact force distribution; (ii) better gravity wrench resistance; (iii) robustness against gripper positioning error; and (iv) ability to resist larger external wrench on the object. We introduce the fingertip score to quantify the grasp performance of a fingertip design over all the objects. The method takes the CAD model of the objects as the input and outputs the optimal grasp location and the best finger design. We use the method for a three-point grasp with a parallel jaw gripper. We validate our method on two sets of objects. Results show how each grasp quality measure behaves on different objects and the variation in the fingertip score with finger design. Finally, we test the effectiveness of the optimal finger design experimentally. The three-point grasp is suitable for grasping objects larger than is possible with shape-matching fingertips.