Orthogonal Displacement Research Articles

Binder-Responsive DNA Strand Displacement Enables High-Throughput and High-Fidelity Discovering of Small Molecular DNA Binders.

High-throughput screening (HTS) is pivotal in the discovery of small molecules that bind to DNA, yet there are limited sensing mechanisms available for designing HTS assays for DNA binders. Herein, we introduce a binder-responsive toehold-mediated DNA strand displacement (BR-TMSD) technique featuring programmable reaction kinetics in response to DNA-binder interactions. When two DNA binders are used, BR-TMSD is initiated through a rapid binder displacement, followed by the DNA strand displacement. The orthogonal displacement reactions of BR-TMSD enables a high-fidelity, dual-channel HTS assay, returning 19 new DNA binders from a library of 1,170 compounds.

Nonlinear design, analysis, and testing of a single-stage compliant orthogonal displacement amplifier with a single input force for microgrippers

To achieve dexterous and stable micro/nanomanipulation, a large grasping stroke, compact design, and parallel grasping are required for microgrippers; thus, a single-stage compliant orthogonal displacement amplifier (CODA) with a single input force would be an ideal transmission mechanism. However, the existing small-deflection-based design schemes cannot adapt to large deflections or shearing effect, thereby affecting the orthogonal movement transformation accuracy. This study proposed, analyzed, and experimentally investigated a nonlinear design scheme for a single-stage CODA with a single input force. First, the nonlinear design principle is described qualitatively. By combining closed-form analytical modelling, finite element analysis, and numerical fitting, the nonlinear extent of a pre-set variable cross-sectional beam in the CODA is formulated. By utilizing the beam constraint model and small-deflection-based modelling, the nonlinear extent of the undetermined uniform straight beam in the CODA is derived. Based on the design principle and nonlinear models, a nonlinear design scheme is proposed quantitatively. Finite element simulations and experimental tests are conducted to verify the proposed scheme, and the limitations of our previous study are revealed.

Analytical solutions for the free vibration of cross-ply composite laminated plates with arbitrary biaxial symmetric geometry

This paper presents an analytical model for the free vibration of composite laminated plates with arbitrary biaxial symmetric geometry under elastic boundary conditions, applicable to cross-ply fiber-reinforced composites. In this model, the domain segmentation integral method proposed by the authors is extended to the first-order shear deformation theory (FSDT) and the laminated plate theory. The energy integrals pertaining to the FSDT are analytically simplified by segmenting the integration domains and synthesizing orthogonal polynomial displacement functions over the plate domain coordinate intervals. This synthesis is achieved through the amalgamation of the penalty function method and the Gram-Schmidt orthogonalization process. Then, using the Rayleigh-Ritz procedure, a series solution for the free vibration problem of cross-ply fiber-reinforced composite laminated plates is obtained. The model provides an analytical mathematical relationship between the profile curve of composite laminated plates with arbitrary biaxial symmetric geometry and the strain energy, kinetic energy, and boundary potential energy during vibrational processes. The correctness and applicability of the method are validated by comparing the obtained results with those from the literatures. New results for laminated plates, such as hexagonal and astroid-shaped plates, were presented as references for future research. Taking a track shaped plate as an example, the effect of the number of layers on the vibration characteristics of cross-ply fiber-reinforced composite laminated plates with a certain thickness is studied.

A Self‐Decoupled and High‐Resolution 2D Displacement Sensor Based on Triboelectric Nanogenerator for Manipulator Precision Positioning

Abstract2D displacement sensor (2DDS) is significant in precision manufacturing positioning, machine condition monitoring, robotic manipulation, and human–computer interaction system. However, the reported 2DDSs have severe limitations, such as low accuracy, poor decoupling, and lack of smart signal analysis. Herein, a self‐decoupled and high‐resolution 2DDS based on two freestanding triboelectric nanogenerators (F‐TENGs) is presented. This sensor achieves self‐decoupling by two orthogonal and independent 1D displacement sensors with low‐cost grating‐structured PCB. The test results of the sensor exhibit a high accuracy ≥99.06% (1D) and 98.94% (2D). Also, the experimental and simulation results demonstrate that this sensor has a high resolution of 200 µm and the function of initial position identification. A 2D displacement sensing system is developed that is capable of collecting F‐TENGs’ open‐circuit voltages in real‐time and performing 2D trajectory synthesis and display. This work expands the potential application of the TENG‐based 2DDS in robotic precision machining.

Evaluation of Computational Analysis for Stiffened Slab Using Finite Strip Method

A rectangular slab stiffened by ribs oriented perpendicular to the support of the slab as structurally equivalent to an orthotropic plate has been analyzed using the finite strip method. The analytic formulation was obtained from the governing equation of motion of the plate using the classical plate theory to an arbitrary boundary and initial condition. The stiffness formulation from total internal energy was considered. The force-displacement equation technique by applying stiffness and uniformly distributed loading was used to obtain the modal solution and hence, displacement at an arbitrary point of the plate for the assumed harmonic function. Approximate stresses following the displacement are also obtained. The comparative solution of the equilibrium differential equation is obtained by means of convergent series expansions of levy plates and the application of Timoshenko and Woinowsky-Krieger averaging of bending rigidity, utilizing suitable orthogonal displacement functions. A computer procedure based on the finite strip method is given through the application of numerical examples, which shows that the procedure provides good results, especially with low discretization and computational effort.

Influences of Tides, Winds, and Bathymetry on Surface Transport Through a Complex Nearshore System: Measurements from GPS Drifters and an Uncrewed Aerial Vehicle

Bathymetric features such as dredged channels, constricted-inlet basins, and nearshore islands have known influences on coastal transport, which are typically studied on an individual basis. However, their interactive effects on flow when found in the same area are poorly characterized. A multi-season study was conducted to characterize surface transport in and around Wood Island Harbor, in the southwestern Gulf of Maine, where these features all exist in close proximity. Patterns of surface transport were assessed with repeated series of Uncrewed Aerial Vehicle flights and deployments of GPS drifters across tidal conditions and winds typical to the area. Transport followed a major axis through the harbor, as a result of the combined effects of the linked inlet-channel system. Despite the complex topography, the individual dynamics of transport are maintained. Tidal variations explained a majority of displacement (R2 = 0.752) along the channel axis, while across-channel wind velocity explained the majority of orthogonal displacement (R2 = 0.646). Flow in the area was friction-dominated, and both inter-island passages and the deep channel served to direct flow. The offshore transport of tidally driven flows from a constricted-inlet basin was enhanced by deep channels, with flow primarily following bathymetric contours. Our observations suggest that surrounding topography lessened the role of wave energy in governing transport. The co-occurrence of bathymetric features around a constricted-inlet basin can disrupt the typical influences of physical mechanisms on surface transport, leading to a greater importance of local conditions and the larger-scale circulation of the area.

A hybrid shell-beam element for straight thin-walled tubular structures

A novel beam model is proposed in order to consider deformations of its cross-section in the context of straight thin-walled tubes. For this purpose, the straight beam kinematics is enriched by addition of orthogonal shell-type displacement field of the tube section. Linear strain in terms of displacement is considered in conjunction with the non-linear coupling between local deformation of the section and its global rotation. Both Euler–Bernoulli and Love-Kirchhoff hypotheses for beam and shell kinematics, respectively, are adopted as well as the thin-walled assumption. First-order shear deformation for the radial variable and Fourier expansion in terms of the circumferential variable are also considered for the mid-surface displacement field. Then, the stress tensor is obtained under plane stress conditions. The virtual power principle is finally used to obtain the equations of motion satisfied by the corresponding generalized forces. Afterwards, an explicit updated Lagrangian Finite-Element approach using a lumped mass matrix is proposed for solving the tube governing equations and the stability condition of the time integration is given. Test-cases are then chosen to assess the present tube finite-element. Both static and dynamic problems are considered. First, the proposed model is compared to analytical solutions. Finally, a tube subjected to a distributed patch loading is studied. The influence of the number of Fourier modes, of warping and coupling terms is examined. The proposed model makes it possible to retrieve classical shell solution of the cross-section deformation with significant computational savings.

Extensional structures of the Nan′an Basin in the rifting tip of the South China Sea: Implication for tectonic evolution of the southwestern continental margin

Nanan Basin is a giant hydrocarbon basin, but its tectonic division scheme and associated fault systems has not been well understood. Based on newly acquired seismic data from the southwestern margin of the South China Sea, this study analysed the structural units, tectonic feature and geodynamics of the sedimentary basin. The new data suggests that the Nanan Basin is a rift basin oriented in the NE-SW direction, rather than a pull-apart basin induced by strike-slip faults along the western margin. The basin is a continuation of the rifts in the southwest South China Sea since the Late Cretaceous. It continued rifting until the middle Miocene, even though oceanic crust occurred in the southwest subbasin. However, it had no transfer surface at the end of spreading, where it was characterized by a late middle Miocene unconformity (reflector T3). The Nanan Basin can be divided into eight structural units by a series of NE-striking faults. This study provides evidences to confirm the relative importance and interplay between regional strike-slips and orthogonal displacement during basin development and deformation. The NE-SW-striking dominant rift basin indicates that the geodynamic drivers of tectonic evolution in the western margin of the South China Sea did not have a large strike-slip mechanism. Therefore, we conclude that a large strike-slip fault system did not exist in the western margin of the South China Sea.

Design of compliant mechanisms: An explicit topology optimization method using end-constrained spline curves with variable width

In this study, an approach using moving end-constrained spline (ECS) curves with variable widths is presented for the explicit topology optimization of compliant mechanisms. The proposed approach uses a series of spline curves to represent the topology of the compliant mechanism. Instead of using a fixed width, we let the width of such spline curves vary along the curve. The optimized design is obtained by optimizing the width of the spline curves and the position of the control points. To avoid infeasible solutions in the design process, the end points of several specific spline curves are constrained according to the design region. The validity of the proposed method is demonstrated using different types of splines, such as the Bézier curve and B-spline curve, for the design of a force inverter, a compliant gripper and a compliant orthogonal displacement amplification mechanism.

Approaches for investigation of oriented cracks of reservoirs using multicomponent VSP

The paper analyses the VSP data inversion in order to determine elastic constants of a transversely isotropic medium with a horizontal axis of symmetry of an infinite order (HTI), simulating an oriented fractured reservoir. Acquisition system of VSP is characterized by the absence of sub-horizontal directions of propagation of seismic waves. In this regard, it was necessary to determine the accuracy with which the elastic constants of the anisotropic layer are restored. The seismograms of the full wave field were selected as the initial data, calculated synthetically for the model of the medium containing azimuthally anisotropic layers. A complex of compressional and shear waves propagating from a source and recorded in the well. In such layers, the shear wave incident on the roof of the HTI layer splits into two waves that propagate at different velocities and have a mutually orthogonal displacement vectors. The processing task was to select waves S 1 and S 2 and build their arrival time curves. These arrival time curves were used in the inversion. The inversion was solved in the form of minimizing the functional of the mean square residual. Elastic constants, determined by inversion, almost exactly coincided with the model ones. The results obtained show the validity of the chosen approach for solving the inverse problem.

Effects of four drying methods on Ganoderma lucidum volatile organic compounds analyzed via headspace solid-phase microextraction and comprehensive two-dimensional chromatography-time-of-flight mass spectrometry

The effect of four drying methods (namely, sun drying, vacuum freeze drying, vacuum drying, and hot air drying) on the fresh Ganoderma lucidum volatile organic compounds (VOCs) was studied by their separation via headspace solid-phase microextraction and identification via comprehensive two-dimensional chromatography-time-of-flight mass spectrometry. In total, 247 kinds of VOCs, mainly composed of alcohols, aldehydes, esters, ketones, and olefins, were identified. Orthogonal partial least squares discriminant analysis and displacement test combined with the variable important in the projection method revealed that VOCs' types and contents in Ganoderma lucidum were influenced by the particular drying method, which could be identified using specific organic compounds. The heating process increased the content of aldehydes, esters, and olefins and reduced alcohol and ketones' content. Since 3-propoxy-1-Propene, 2-pentyl-Furan, Acetic acid, 2-Butanone, 1-Pantano, and other VOCs did not disappear during the drying process, they can be used for the classification and identification of Ganoderma lucidum species and other edible fungi.

Revisiting the unrepaired unilateral cleft lip and nasal deformity using 3D surface image analysis: A data-driven model and its implications

Current descriptions of the unilateral cleft lip and nasal deformity (uCLND) are based upon limited sample sets and subjective observations. While those descriptions are inconsistent and contradictory, theoretical models, including Hogan's "tilted tripod" and Fisher's "nasal arch forms", have never been tested. Given that favorable outcomes of treatment remain elusive, detailed study of the deformity is critical in devising better treatments. The purpose of this study was to develop a data-driven three-dimensional (3D) model of uCLND that spans the spectrum of presentation and involves a pervasive underlying mechanism. We studied 3D images of 100 infants with unrepaired cleft lip at 6 months of age. Objective assessment included the landmark positions, anthropometric dimensions, and shape-based measures. Cleft severity was stratified by the lateral displacement of subnasale, so that a model could be developed using linear regression. With progressive deviation of subnasale, the non-cleft alar base moved lateral, the cleft alar base was left posterior, and the nasal dorsum followed the caudal septum (deviating towards the non-cleft side). The "twist" resulted in opposing cleft alar dome collapse, non-cleft alar ring constriction (the non-cleft nasal sill narrowed, lateral genu rose, and alar-cheek junction became more acute), and displacement of the philtrum from midline. Our study not only supports theoretical models of uCLND but also clarifies vectors of change and reveals significant non-cleft side alterations. On the basis of our findings, the objectives of treatment should involve centralization of the columella and philtrum and rebalancing the nose by untwisting the orthogonal displacement of the alar bases.

Orthogonal binding and displacement of different guest types using a coordination cage host with cavity-based and surface-based binding sites.

The octanuclear Co(ii) cubic coordination cage system H (or HW if it bears external water-solubilising substituents) has two types of binding site for guests. These are (i) the partially-enclosed central cavity where neutral hydrophobic organic species can bind, and (ii) the six 'portals' in the centres of each of the faces of the cubic cage where anions bind via formation of a network of CH⋯X hydrogen bonds between the anion and CH units on the positively-charged cage surface, as demonstrated by a set of crystal structures. The near-orthogonality of these guest binding modes provides the basis for an unusual dual-probe fluorescence displacement assay in which either a cavity-bound fluorophore (4-methyl-7-amino-coumarin, MAC; λem = 440 nm), or a surface-bound anionic fluorophore (fluorescein, FLU; λem = 515 nm), is displaced and has its emission ‘switched on’ according to whether the analyte under investigation is cavity-binding, surface binding, or a combination of both. A completely orthogonal system is demonstrated based using a Hw/MAC/FLU combination: addition of the anionic analyte ascorbate displaced solely FLU from the cage surface, increasing the 515 nm (green) emission component, whereas addition of a neutral hydrophobic guest such as cyclooctanone displaced solely MAC from the cage central cavity, increasing the 440 nm (blue) emission component. Addition of chloride results in some release of both components, and an intermediate colour change, as chloride is a rare example of a guest that shows both surface-binding and cavity-binding behaviour. Thus we have a colourimetric response based on differing contributions from blue and green emission components in which the specific colour change signals the binding mode of the analyte. Addition of a fixed red emission component from the complex [Ru(bipy)3]2+ (Ru) provides a baseline colour shift of the overall colour of the luminescence closer to neutral, meaning that different types of guest binding result in different colour changes which are easily distinguishable by eye.

Parameter calibration of 6-degree-of-freedom parallel mechanism based on orthogonal displacement measuring system

Aiming at simplifying the parameter calibration process of the 6 degree-of-freedom(6-DOF) parallel mechanism, improving the calibration efficiency, and reducing the calibration cost, this paper proposes a pose measurement device and method based on the Orthogonal Displacement Measurement (ODM) system. First, the pose calculation method of the proposed device is studied, and its forward and inverse kinematics solutions are solved using spatial analytic geometry method; second, an error model for the combination of the parallel mechanism and the ODM system is constructed using the infinitesimal displacement synthesis method; third, based on the proposed error model, a mathematical model is constructed for the optimization problem of the parameter error identification of the combination, wherein the minimization of the sum of squares of in, the indicating value displayed by the sensor, is taken as the objective function, and the structural parameter errors of the combination are taken as the design variables; at last, the ODM system is used to measure the pose of the 6-DOF parallel mechanism, and the OASIS software is adopted to directly find out the optimal solutions of the parameter errors and compensate them to the parallel mechanism control system, so as to complete the parameter calibration of the parallel mechanism. The comparison result of the pose errors before and after the calibration shows that, the maximum position error has been reduced by 69 %–94 %, and the maximum posture error has been reduced by 87 %–97 %. Using ODM system to calibrate the parameters of the parallel mechanism can not only effectively improve the positioning accuracy of the parallel mechanism, but also simplify the calibration work, improve the calibration efficiency, and reduce the calibration cost.

A New High Precision Linear Displacement Sensor Based on Single Light Field Orthogonal Modulation

This paper present a single light field orthogonal modulation displacement measurement method which is based on time and space modulation technology. This method uses an alternating light intensity modulation in the time domain and modulation of four sinusoidal light-transmitting surfaces in the spatial domain to synthesize a traveling wave signal. The displacement was accurately reflected in the phase shift of the traveling wave signal, which could be measured by the time difference. A prototype with a measuring range of 500 mm and a pitch of 0.6 mm was fabricated to evaluate the proposed method. Combined with the measurement mechanism, the measurement errors caused by the spatial modulation were analyzed in detail. To reduce those primary periodic errors, we proposed an optimization structure of continuous cosinusoidal transmitting surfaces and demonstrated the effectiveness of this method by simulations and experiments. The experimental results indicate that the short period measurement accuracy reached ±0.29 $\mu \text{m}$ with 1 nm resolution within one period of 0.6 mm, which means that the accuracy in one period (0.6 mm) exceeded 0.1%. Furthermore, the original measurement accuracy of the full range of 500 mm was ±1.3 $\mu \text{m}$ , the error showed great regularity, and the better performance of the sensor could be obtained by digital calibration for the measurement data or improvement in the structure. Therefore, compared with the traditional measurement methods, the sensor described in this paper can achieve high-precision measurement with a low cost of manufacture.

Cyclic behavior of gravel–steel interface under varying rotational shear paths

Cyclic rotational behavior of a soil–structure interface is imperative for understanding the three-dimensional behavior; this requires testing the interface under systematically varying rotational shear paths. A series of cyclic tests were conducted on the gravel–steel interface along linear, elliptical, and circular shear paths by systematically varying the orthogonal amplitude shear displacement ratio. The resultant peak shear stress was observed to be independent of the shear direction and dependent on the shear path. The interface demonstrates a coupling response among the orthogonal shear directions during the rotational shear, which governs the three-dimensional shear mechanism. Owing to such coupling, during the cyclic shear, the unloading extent from the resultant peak loading state at different quarters of a shear cycle diminishes as the shear path changes toward a circle; this leads to the monotonous shear proceeding in a circular route with an insignificant change in the shear direction. Significant dilatancy is induced by rotational shear, which can be divided into irreversible and reversible components. The final compression of the irreversible dilatancy increases as the area under the rotational shear path increases. The reversible dilatancy diminishes as the shear path becomes a circle. The interface evenly demonstrates aeolotropy under the rotational shear condition.

A mixed‐integer linear model for the multiple heterogeneous knapsack problem with realistic container loading constraints and bins' priority

AbstractWe propose a mixed‐integer linear model that solves the multiple heterogeneous knapsack problem, minimising the wasted space of the bins, taking into account their priority and considering the following constraints: non‐overlapping, boundaries and positioning (both constrained and free), rotations (around the vertical axis), orthogonal displacement, weight limit, static stability, weight distribution in a pyramidal region and load bearing considering items' arbitrary centre of mass (CoM). In the experiments, the priority parameter is set to prioritise smaller bins, but the model is generic to cover other cases. We study the trade‐off of adding more constraints to make the problem more realistic and the complexity of finding a solution. We introduce new metrics that facilitate the comparison of datasets used in experiments. These metrics allow the export of theoretical results in the industry. We also propose a constructive heuristic named weight first best fit to handle large‐scale instances in a reasonable time.

A novel compression-based compliant orthogonal displacement amplification mechanism for the typical actuators used in micro-grasping

Transforming movement orthogonally and enlarging grasping stroke simultaneously is a key issue in micro-grasping. In this paper, a novel compression-based compliant orthogonal single-stage displacement amplification mechanism (DAM) is proposed, which can not only realize orthogonal movement transformation and displacement amplification without requiring bidirectional symmetric input forces/displacements, but also obtain increasing displacement amplification ratio with the increase of input force. Inspired by the stress stiffening geometrical nonlinearity, the structural design of proposed DAM is presented, and the feasibility of conceptional design is discussed. Based on finite difference modeling and Euler–Bernoulli beam theory, the nonlinear analysis of displacement amplification ratio is presented. Finite element analysis (FEA), including the small deflection-based static FEA, nonlinear buckling FEA, as well as static FEA considering geometrical nonlinearity is used to verify the performance of proposed DAM. Finally, experimental verification is conducted.

Degradation of submerged/wet concrete under cyclic compression and cyclic shear

The aim of this study is to identify a specific degradation of concrete that has been observed in bridge decks made of reinforced concrete (RC). To control the phenomenon, fundamental studies were conducted. Compressive loads and external water pressure were cyclically applied to submerged concrete cylinder specimens with different pre-loading and restraint conditions. The turbidity of the water in the tank was generally observed during the loading, and the pH of the turbid water steadily increased as the number of cycles increased. Thereafter, fine aggregates without a cement matrix were found on the inner surfaces of split specimens. These phenomena were quantitatively analyzed, and the analyses suggested that cyclic water pressure acted on the inside of pre-cracked specimens and washed out their cement matrix. The degradation of a rough cracked surface was also examined using the cyclic shear test, with/without a water supply to the crack. The shear slip and the orthogonal displacement were clearly amplified with an increase in the number of cycles when the water supply was present. The mechanical properties of cracked concrete with water in shear was discussed in accordance with that of liquefaction. These fundamental studies could help to determine the acceleration factors of the degradation and provide certain thresholds for practical use.

Topological design of compliant orthogonal displacement amplification mechanism under the unidirectional input force

The orthogonal displacement amplification mechanism is used to output and amplify the displacement perpendicular to the direction of the input force, and its configuration often uses a typical bridge-type. However, the bridge-type amplifier to achieve orthogonal shift conversion must enter the bidirectional symmetric input forces, otherwise the output will produce parasitic displacement. In view of this problem, the topology optimization method is used to find the new configuration of the displacement amplification mechanism, so that it can still realize the orthogonal displacement transformation under the unidirectional input force condition. Based on the solid isotropic material with penalization (SIMP) topological description method, the ratio of output and input displacements is maximized as the objective function, the ratio of parasitic displacement and output displacement as one of constraint functions, and the topological optimization mathematical model of the compliant orthogonal displacement amplifier is established under the unidirectional input force. The sensitivity information of the objective and constraint functions is deduced by the adjoint matrix method, and the optimization problem is solved by the method of moving asymptotes (MMA). The topology optimization results of orthogonal displacement amplifier are given through numerical examples, and the effect of spring stiffness on the topology optimization result is also discussed. Finally, the parasitic motions of the displacement amplification mechanism obtained from topology optimization and the bridge-type amplification mechanism are compared through the finite element analysis and experiment. Finite element simulation and experiment confirm the correctness and validity of the proposed method.