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This paper demonstrates the analytical and numerical investigations for the obtainment of the predefined critical parameters of double-layer tape spring (DLTS) hinges. The DLTS hinge is utilized for the coupling between the solar panels to assist the accommodation and formulation of the assumed origami-based pattern of the solar arrays. They are examined for the assurance of safety, durability, non-permanent deformation, and stability from the stowed to the deployment configuration. Von Misses stress (σv) and steady-state moment simulations are investigated by varying the critical hinge design parameters of curvature radius (R), subtended angle (θ) and layer thickness (t). Two optimization models, Taguchi and response surface methodology/RSM, are utilized by employing the computational findings to obtain and validate the modified optimal geometric parameters within this analytical experiment. For the Taguchi method, the optimization of σv and the steady-state moment is accomplished with a t of 1.75–2.25 mm, R of 1.5–2.0 mm, and θ of 1–1.2°. Furthermore, the RSM model shows that the t, R, and θ parameters are determined to be 2.90 mm, 2 mm, and 1.35°, respectively. For optimization of the hinge design, both models should be considered for improved verification and accuracy of the results. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate functional outcome and complications after primary and revision modular H-TKA using hybrid fixation with cementless stems. Methods: Between 2015 and 2018, 48 patients with 50 implants were included after hybrid implantation of a single design H-TKA system using cementless osseointegrating stems and modular components. Complications and clinical outcome were analysed using Knee Society Score (KSS), the Western Ontario McMasters Universities Osteoarthritis Index (WOMAC) and the Short-Form Health Survey 12 (SF-12) score. Results: Indications for implantation were aseptic revision (n = 29, 58%), primary TKA (n = 19, 38%) and two-stage septic revisions (n = 2, 4%). Complications were reported in 26% (n = 12), whereas complications associated with hybrid fixation occurred in 5 (10%) cases, with 2 (4%) requiring revision surgery for aseptic loosening and 3 (6%) treated with an adapted postoperative protocol for perioperative fractures. Implant survivorship was 84% after a mean follow-up of 54 months. Postoperative KSS significantly improved from 51.50 (12–100) to 78.36 (41–99; p < 0.001). The mean WOMAC score was 19.26 (0–55), SF-12 PCS was 41.56 points (22.67–57.66) and SF-12 MCS was 49.21 points (23.87–63.21). Conclusion: Hybrid modular implantation in H-TKA provides satisfactory clinical and functional results in primary and revision TKA. Clinical outcomes significantly improve with reduced pain, increased mobility, and good-to-excellent functional scores after implantation. Whilst implant survival is comparable to previous studies and complications associated with hybrid fixation are low, general complication rates are comparably high. [ABSTRACT FROM AUTHOR]

To identify the clinical characteristics of fractured hinges after open-door cervical laminoplasty for cervical canal stenosis and explore the relationship between hinge fractures and axial symptoms. This was a retrospective study of patients with cervical myelopathy who underwent open-door laminoplasty between November 2014 and November 2016 at the Affiliated Hospital of Qingdao University. Cervical CT scans were performed after surgery and the Takeuchi criteria were applied to evaluate the postoperative axial symptoms. Of 223 opened laminae in 67 patients, 67 laminae (30.0%) in 30 patients (44.8%) showed fracture. The frequency of hinge fractures was higher at C6 (53.7%). Forty-nine fractured laminae (73.13%) were non-displaced and 18 were displaced. At 3 months, 33 fractured laminae (49.3%) showed bony union on CT, and union rates were 86.6% and 91.0% at 6 and 12 months, respectively, indicating that the union rate was lower for displaced fractures than for non-displaced fractures. Among the 67 patients, 14 had axial symptoms: three of 37 (8.1%) patients without hinge fractures and 11 of 30 (36.7%) patients with hinge fractures. One year later, the hinge fractures were healed in 24/30 patients. Among the six unhealed patients, five still suffered from axial symptoms. The frequency of axial symptoms was higher in the patients with three or more hinge fractures (66.7%) than in the patients with only one (16.7%) or two (46.7%) hinge fractures. Patients with hinge fractures may have an increased risk for axial symptoms after open-door cervical laminoplasty. The frequency of axial symptoms decreases with fracture healing. [ABSTRACT FROM AUTHOR]

Common knowledge is ubiquitous in our lives and yet there remains considerable uncertainty about how to model or understand it. Standard analyses of common knowledge end up being challenged by either regress or circularity which then give rise to well-known paradoxes of practical reasoning, such as the Two Generals' Paradox. This paper argues that the nature and utility of common knowledge can be illuminated by appeal to Wittgenstein's Hinge Epistemology. It is argued that those things that we standardly think of as being common knowledge in our lives are the same as those that Wittgenstein identified as hinge certainties. This identification of common knowledge with hinge certainties allows us to resolve the regress problem for common knowledge and explain how the Two Generals' Paradox arises. [ABSTRACT FROM AUTHOR]

This study surveys the impacts of injection parameters on the deformation rate of the injected flexure hinge made from ABS, PP, and HDPE. The flexure hinges are generated with different filling time, filling pressure, filling speed, packing time, packing pressure, cooling time, and melt temperature. The amplification ratio of the samples between different injection parameters and different plastic types is measured and compared to figure out the optimal one with a high amplification ratio. The results show that the relationship between the input and output data of the ABS, PP, and HDPE flexure hinges at different injection molding parameters is a linear relation. Changing the material or many injection molding parameters of the hinge could lead to a great impact on the hinge's performance. However, changing each parameter does not lead to a sudden change in the input and output values. Each plastic material has different optimal injection parameters and displacement behaviors. With the ABS flexure hinge, the filling pressure case has the greatest amplification ratio of 8.81, while the filling speed case has the lowest value of 4.81. With the optimal injection parameter and the input value of 105 µm, the ABS flexure hinge could create a maximum average output value of 736.6 µm. With the PP flexure hinge, the melt temperature case achieves the greatest amplification ratio of 6.73, while the filling speed case has the lowest value of 4.1. With the optimal injection parameter and the input value of 128 µm, the PP flexure hinge could create a maximum average output value of 964.8 µm. The average amplification ratio values of all injection molding parameters are 6.85, 5.41, and 4.01, corresponding to ABS, PP, and HDPE flexure hinges. Generally, the ABS flexure hinge has the highest amplification ratios, followed by the PP flexure hinge. The HDPE flexure hinge has the lowest amplification ratios among these plastic types. With the optimal injection parameter and the input value of 218 µm, the HDPE flexure hinge could create a maximum average output value of 699.8 µm. The results provide more insight into plastic flexure hinges and broaden their applications by finding the optimal injection parameters and plastic types. [ABSTRACT FROM AUTHOR]

In the active compliance assembly systems for large components, the perception accuracy of contact force between assembled components is an important factor affecting the alignment accuracy and the assembly stress of components. The installation angle errors of the three-dimensional force sensor (TDFS) are considered the primary error source affecting the perception accuracy of contact force. In this paper, a self-calibration method for the TDFS installation angle is presented. Firstly, the contact force calculation model of the assembled components is established, and the influence of the TDFS installation angle error on the perception accuracy of the contact force is analyzed. Secondly, a self-calibration method of the TDFS installation angle is proposed according to the relationship between the contact force of the spherical hinge and the posture of the assembly systems terminal. Then, the uncertainty of the proposed calibration method is analyzed by the Monte Carlo method, and the results show that the proposed method has higher calibration accuracy. Finally, an experimental platform for self-calibrating the installation angle of TDFS is built. The assembly experiment results show that compared with the traditional method, the proposed method can not only improve the alignment accuracy of the assembly feature, but also reduce the assembly contact force. [ABSTRACT FROM AUTHOR]

The design, analysis, fabrication, and characterization of two distinct MEMS rotational structures are provided; these structures include a classical symmetrical lancet structure and a novel symmetrical C-shaped structure provided with a tilted arm, and both are actuated by thermal actuators. Our proposed C-shaped structure implemented a curved beam mechanism to enhance the movement delivered by the thermal actuators. The geometrical parameters of our proposed device were optimized using the design of experiment (DOE) method. Furthermore, the analytical modeling based on Castigliano's second theorem and the simulations based on the finite element method (FEM) were used to predict the behavior of the symmetrical C-shaped structure; the results were in good agreement with each other. The MEMS-based rotational structures were fabricated on silicon-on-insulator (SOI) wafers using bulk micromachining technology and deep reactive ion etching (DRIE) processes. The fabricated devices underwent experimental characterization; our results showed that our proposed MEMS rotational structure exhibited a 28% improvement in the delivered displacement compared to the symmetrical lancet structure. Furthermore, the experimental results showed good agreement with those obtained from numerical analysis. Our proposed structures have potential applications in a variety of MEMS devices, including accelerometers, gyroscopes, and resonators, due to their ability to maximize displacement and thus enhance sensitivity. [ABSTRACT FROM AUTHOR]

Introduction: Unicompartmental knee replacement (UKR) is an effective surgical strategy in patients with isolated medial or lateral compartment osteoarthritis. Study aims were to (1) describe the epidemiology of patients undergoing revision of UKR to a hinge knee replacement (HKR); (2) identify factors influencing time to revision; (3) evaluate HKR survival. Materials and methods: An analysis of National Joint Registry data was undertaken, exploring revision of UKR to HKR between 2007 and April 2021. Descriptive analysis of eligible patients and Cox Regression to identify key determinants of time to revision were performed. Failure of HKR post-revision was assessed using survival analysis. Results: 111 patients underwent revision of UKR to HKR. Median age at revision was 70 years and most common indications were instability (n = 42) and infection (n = 22). The most common implant was a rotating HKR. Significant independent factors associated with earlier revision were periprosthetic fracture (p = 0.03) and malalignment (p = 0.03). Progressive osteoarthritis (p = 0.01) and higher ASA grades (3: p = 0.01, 4: p < 0.01) delayed time to revision; patient sex and age were not significant factors. Ten patients required subsequent re-revision; median age at re-revision was 61 years. HKR revised from UKR had an 89.3% revision-free risk at 5 years. Male sex (p < 0.01) and younger age (p < 0.01) were associated with re-revision. Conclusions: Factors associated with time to revision may be used to counsel patients prior to UKR. The survivorship of the HKR of 89.3% at 5 years is concerning and careful consideration should be given when using this level of constraint when revising UKR in younger or male patients. [ABSTRACT FROM AUTHOR]

Flexure-based grippers offer an attractive alternative to conventional grippers used in robotics and automation. However, most existing designs appear to suffer from insufficient range of motion, loadability, and support stiffness. This article presents an approach to obtain well-performing flexure hinges for compact anthropomorphic grippers made via metal additive manufacturing. We propose a flexure hinge architecture that achieves a high range of motion despite the challenging combination of a small design space, high Young's modulus, and limited minimum feature size. Furthermore, we present an optimization procedure to generate suitable tendon-driven designs with high loadability. Using this framework, a flexure hinge with an outer diameter of 21.5 mm and range of motion of ±30 deg is synthesized. For the range of 0-30 deg, simulations show a lateral loadability of 52.5-18.6 N and lateral support stiffness of 12,309-11,130 N/m, determined at a gripper interface located 41.2 mm from the hinge pivot axis. Experiments confirm a loadability of at least 15.4 N and determined a stiffness of 8982 to 9727 N/m for same conditions. The results show that the flexure hinge architecture has large potential for a wide range of applications, while in combination with the optimization procedure, superior designs for tendon-driven grippers can be obtained. [ABSTRACT FROM AUTHOR]

Deployable structures inspired by origami have gained significant prominence in space applications, including solar arrays, reflector arrays, and satellite antennas. Traditionally, these structures consist of separate components that are folded during launch and later deployed in space using springs or actuator mechanisms. However, recent advancements in multi-material additive manufacturing have opened new possibilities for the fabrication of monolithic structures, integrating deployable mechanisms into a single entity. In this paper, we present a novel framework for designing unidirectional (UD) and bidirectional (BD) hinges utilizing viscoelastic materials, incorporated into rigid plates, forming deployable structures. These hinges exhibit the unique ability to store strain energy upon deformation and self-deploy to a flat configuration when released. The experimental results presented here demonstrate the effectiveness and feasibility of our hinge designs in real-world applications. To demonstrate the practical applicability of these hinge designs, we construct a Repeating Unit Cell (RUC) of a large origami-inspired deployable structure, showcasing their compatibility with popular deployable structure patterns. [Display omitted] • Designed Multi-material, monolithic structure with viscoelastic hinges. • Stored strain energy helps to self-deploy the hinge when released. • Designed topology of the hinge structure to allow for higher strain energy storage. • Designs also allow for minimal local buckling and easy self-deployment. • Experimentally verified hinges that are biased unidirectionally or bidirectionally. [ABSTRACT FROM AUTHOR]

Micro-newton thrust stands are widely used in thruster ground calibration procedures for a variety of space missions. The conventional analytical model does not consider the gravity-induced extension effect and systematic error in displacement for thrust stands consisting of hanging pendulums based on flexure hinge structures. This paper proposes an improved analytical model of a hanging pendulum for thrust measurement, where an elliptical notched flexure hinge is the key component. A parametric model of the bending stiffness of the flexure hinge is developed. Equally, both the bending stiffness shift under the gravity-induced extension effect and the systematic error in displacement due to the assumed rotational center offset of the hinge are investigated. The presented stiffness equations for elliptical notched hinges can be degenerated into stiffness equations for circular notched as well as leaf-type hinges. The improved model aims to evaluate and highlight the influence of the two considered factors for use in thrust stand parameter design and thrust analysis. A finite element modeling solution is proposed to validate the proposed analytical model. The results show that the proposed model can quantify the hinge bending stiffness shift, which also demonstrates that even a small bending stiffness shift may introduce great uncertainty into the thrust analysis. [ABSTRACT FROM AUTHOR]

The non-variable stiffness of the flexible hinge in the fast-steering mirror (FSM) cannot adapt to varying load demands. To address this issue, this paper presents an innovative variable-stiffness rotational mechanism designed for use with FSMs. Firstly, the working principle of the variable-stiffness mechanism is introduced, and the influence of the length of each structure on the stiffness and the nonlinear influence are analyzed. Then, the variable-stiffness mechanism is applied to the FSM for the variable-stiffness experiment and variable-load experiment. The experimental results show that the variable-stiffness mechanism designed in this paper can realize the change in stiffness. The errors between the experimental value and the theoretical value of the three sets of experiments are +5.72%, +7.57%, and +6.57%. The FSM's stiffness nonlinearity is very small, and the resonance frequency of the FSM before and after increasing the load can be consistent. The variable-stiffness mechanism can change the frequency characteristics by changing the rotational stiffness of the FSM. [ABSTRACT FROM AUTHOR]

A new three-dimensional flexible hinge capable of large, linear-domain displacements is proposed for extended spatial workspace mechanisms. The hinge structure is compact and modular consisting of a large number of circular- and straight-axis segments connected in series and disposed in two parallel planes in a folded manner. The analytical, linear-model compliance matrix, which is necessary in direct/inverse kinematics and controls analysis, is derived based on simplified hinge geometry and small-deformation theory. The compliance model is accurate, as demonstrated by finite element simulation and experimental testing of a prototype. The compliance model is also utilized to determine the hinge piston-motion stiffness and the static response of several hinges connected in series. Another analytical compliance model is formulated to predict the hinge maximum loads and displacements in terms of allowable stresses. The mathematical models are further utilized to comprehensively investigate the influence of geometric parameters on the hinge performance. [ABSTRACT FROM AUTHOR]

Copyright of Annals of Philosophy / Roczniki Filozoficzne is the property of John Paul II Catholic University of Lublin, Faculty of Philosophy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study examines the wing hinge oscillations in an aircraft concept that employs multiple wings, or small aircraft, chained at the wing tips through freely rotatable hinges with minimal structural damping and no mechanical position-locking system. This creates a single pseudo long-span aircraft that resembles a flying chain oriented perpendicular to the flight direction. Numerical calculations were conducted using the vortex lattice method and modified equations for a multi-link rigid body pendulum. The calculations demonstrated good agreement with small-scale wind tunnel experiments, where the motion of the chained wings was tracked through color tracking, and the forces were measured using six-axis force sensors. The total C L / C D increased for the chained wings, even in the presence of hinge joint oscillations. Furthermore, numerical simulations assuming an unmanned airplane size corroborated the theoretical attainment of passive stability with high chained numbers ( ≥ 9 wings), without any structural damping and relying solely on aerodynamic forces. Guidelines for appropriate hinge axis angle δ and angle-of-attack regions for different chained wing numbers to maximize passive oscillation stability were obtained. The results showed that wing-tip-chained airplanes could successfully provide substantially large wing spans while retaining flexibility, light weight and C L / C D , without requiring active hinge rotation control. [ABSTRACT FROM AUTHOR]

This study explores the potential use of new connections to shape precast building geometries, focusing on connection performance, robotic fabrication, and foldable structural elements. Three connection types, including coupled-bolts, hinges, and steel tubes, were initially proposed and assessed in beam and portal frame geometries. In contrast, the study introduces conceptual ideas; initial experimental and numerical studies were conducted to estimate connection capacities. Robotic fabrication for connecting elements to reused concrete and converting floor elements into beams was detailed, showcasing robotic technology's performance and potential. These connections were employed in designing new precast element geometries, ranging from simple beams to multi-story buildings. Geometric properties and volume quantities of folded and opened geometries were studied using 37 CAD models. To properly discuss the joint performance reference, monolithic elements with exact dimensions were created for comparison. Despite varied connection capacity ( 38 % to 100 % ), the steel tube exhibited the most desirable performance, resembling a monolithic element with an exact size. Some proposed foldable geometries showed a significant reduction (up to 7 % ) in element dimensions to facilitate transport and construction. [ABSTRACT FROM AUTHOR]

The article discusses the importance of precise jaw records in prosthodontics for maintaining oral health and function. It reports the need for individualized recording using a face bow due to anatomical variations. It highlights the hinge-like jaw movement during the occlusal-to-rest position transition, which is crucial. It emphasizes the need for meticulous capture and transfer of the hinge axis for precise articulation in dental practice.

Aim and objective: To compare the clinical effect of reconstruction of internal and lateral column periosteal hinge-assisted treatment with Kirschner wire and internal fixation with Kirschner wire in the treatment of multidirectional unstable supracondylar fractures of humerus in children. Methods: A retrospective cohort study was conducted to analyze the clinical data of 48 patients (31 male, 17 female; mean age: 6.7 ± 2.4 years old) with multidirectionally unstable supracondylar fractures of the humerus treated in our Hospital from August 2020 to August 2022. Twenty-five cases were treated with Kirschner wire reconstruction of the internal and lateral column periosteal hinge assisted by closed reduction and Kirschner wire internal fixation (study group). Twenty-three cases were treated with closed reduction and Kirschner wire internal fixation (control group). The operation time, intraoperative fluoroscopy times, percentage of patients who underwent open reduction after failure of closed reduction, fracture healing time, Baumann angle (BA), shaft-condylar angle (SCA), range of motion (ROM), and Flynn score of elbow at the last follow-up were compared between two groups. Complications such as infection and irritation of Kirschner wire tail were observed in two groups 2 months after the operation. Results: All patients were followed up for 10–22 months ([13.85 ± 2.89] months). The average operation time of the control group was 82.1 min, which was significantly longer than that of the study group 32.3 min (P < 0.05). The number of intraoperative fluoroscopy (29.4 ± 9.2) in the control group was significantly higher than that in the study group (15.2 ± 6.3) (P < 0.05). The incision rate of the control group was 17% while that of the study group was 0 (P < 0.05). According to Flynn score, the excellent and good rate of the elbow joint in the control group was 86.9% (20/23). The excellent and good rate of the elbow joint in the study group was 92.0% (23/25) (P > 0.05). There was no significant difference in fracture healing time, BA, SCA, and ROM between the two groups (P > 0.05). No infection or Kirschner wire tail irritation occurred in the two groups during the 2-month follow-up. Conclusion: Reconstruction of internal and lateral periosteal hinges with Kirscher wire has similar effects to closed reduction and Kirschner wire fixation in the treatment of multidirectionally unstable supracondylar fractures of the humerus in children, but it can shorten the operation time and reduce intraoperative fluoroscopy times and incision rate. [ABSTRACT FROM AUTHOR]

Insects use their mandibles for a variety of tasks, including food processing, material transport, nest building, brood care, and fighting. Despite this functional diversity, mandible motion is typically thought to be constrained to rotation about a single fixed axis. Here, we conduct a direct quantitative test of this 'hinge joint hypothesis' in a species that uses its mandibles for a wide range of tasks: Atta vollenweideri leaf-cutter ants. Mandible movements from live restrained ants were reconstructed in three dimensions using a multi-camera rig. Rigid body kinematic analyses revealed strong evidence that mandible movement occupies a kinematic space that requires more than one rotational degree of freedom: at large opening angles, mandible motion is dominated by yaw. But at small opening angles, mandibles both yaw and pitch. The combination of yaw and pitch allows mandibles to 'criss-cross': either mandible can be on top when mandibles are closed. We observed criss-crossing in freely cutting ants, suggesting that it is functionally important. Combined with recent reports on the diversity of joint articulations in other insects, our results show that insect mandible kinematics are more diverse than traditionally assumed, and thus worthy of further detailed investigation. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'. [ABSTRACT FROM AUTHOR]

Establishing a novel design and accurate analytical models for XY nanopositioning stages based on voice coil motor (VCM) actuators is critical to achieving an optimal working performance. To overcome the existing design challenges of 2-degree-of-freedom guiding mechanisms, a four-layer structure composed of L-shaped spatial double parallelogram flexure mechanisms was proposed for the magnetic stage, which exhibits light weight and inhibits parasitic and decoupled motions. The guiding mechanisms were modeled by the compliance matrix method. Thereafter, by combining an electromagnetic model for the VCMs with the equivalent magnetic network method, an electromagnetic–mechanical coupling optimization method with multiple constraints was proposed for the stage to achieve a millimeter-range motion with a maximized natural frequency. The mechanical and electromagnetic performances were then verified by finite element analysis software. The optimized prototype was tested with a stroke of ±3.41 and ±3.08 mm for X axis and Y axis, respectively, a closed-loop resolution of 100 nm for X axis and 150 nm for Y axis, and a resonant frequency of 11.75 Hz for both axes. The tracking of a 0.1 Hz spiral of Archimedes achieved a maximum tracking error of 2.9%. [ABSTRACT FROM AUTHOR]

Motivated by the propulsion of animals using articulated bodies, this study experimentally investigates the deformation and torque generation of a multi-segmented structure undergoing flapping motion. The segmented structure consists of multiple rigid segments connected in a line through elastic sheets functioning as elastic hinges. To enhance the asymmetry in the deflection of the segmented structure between the power and recovery strokes, the elastic hinges are designed to bend only one way from their original position. To characterize the deflection profile of the segmented structure, new definitions are proposed for the effective bending stiffness of the entire structure and the dimensionless speed representing the relative magnitude of the fluid force acting on the structure to its internal bending force. These two quantities are used to determine the tip deflection adjusted by the discrete profile. Two typical deflection responses during the recovery stroke are identified, namely, an in-phase response and a delayed response. The difference in these deflection responses causes substantial changes in torque and thrust generation, particularly during the early stage of the subsequent power stroke. An evaluation of the torque and thrust generation performance, in terms of the net cyclic value and the degree of asymmetry between the two strokes, reveals the optimal model design and operation conditions of the segmented structure. [ABSTRACT FROM AUTHOR]

The frequency variation problem of a classical beam with a rotationally restrained internal hinge arbitrarily located is studied intensively. The characteristic equations of the natural vibration are derived rigorously upon the corresponding boundary conditions and the compatibility conditions at the interconnecting point such that the effects of both the rotational restraint stiffness and the hinge position on the natural frequencies and mode shapes are described comprehensively. In the context, the critical locations of an internal hinge are investigated extensively to obtain the extreme values of a natural frequency of the beam system, and the associated requirements are explored in depth. It appears that the essential conditions for obtaining the critical points with regard to the maximum or minimum frequency come, respectively, from the same compatibility relation of the rotational flexibility in view of the opposite criteria. Numerical results are provided with two representative uniform beams to show the variations of their dynamic characteristics and to gain new insights into the transition conditions in the two distinct cases. [ABSTRACT FROM AUTHOR]

The present study investigates the relation between the optimal geometry (quantified via the minimum thickness) and the number of concurrent hinges at the masonry arch's limit state. The Heymanian assumptions regarding material behavior are adopted, and only constant thickness arches subject to static (i.e., self-weight) loading are considered. First, the only numerically verified completeness of the failure mode types (including 6 and even 7 hinges) of gothic arches is analytically proven. Next, it is investigated whether a higher number of hinges can concurrently occur for arbitrary, symmetric concave arches. A numerical procedure is presented which generates suitable arch geometries corresponding to a k-hinge mechanism, where k is an arbitrary odd integer not smaller than 5. For the generated class of arches, a higher number of concurrent hinges leads to lower minimum thickness values. However, it is explicitly proven that a higher number of hinges is not necessary for lower minimum thickness values. A small database about the geometry of the transversal arches of English and French medieval gothic cathedrals concludes the first part to allow comparison with the derived results. In the second part of the paper, existing literature results on the limit state analysis of gothic arches are extended by the effect of stereotomy on the failure mode type and minimum thickness value. [ABSTRACT FROM AUTHOR]

As an important branch of weakly supervised learning, partial label learning (PLL) tackles the problem where each training instance is associated with a set of candidate labels, among only one is correct. Most existing PLL algorithms elaborately designed loss functions and update strategies to learn potential ground-truth labels among candidate labels with deep neural networks. However, these algorithms are susceptible to the cumulative error caused by noisy label propagation when updating label confidences, this will make the deep models tend to overfit the noisy labels, thereby achieving poor generation performance. To remedy this issue, we propose a general framework multi-class partial hinge loss (MPHL) for PLL, which can disambiguate the candidate labels by optimizing the margin between the maximum modeling output from partial labels and that from non-partial ones. More importantly, the partial hinge loss can adaptively optimize the separation hyperplane to reduce the influence of cumulative error. Meanwhile, we introduce graph laplacian regularization to full mine the relationship between candidate labels of similar instances to constrain the separation hyperplane to improve the robustness of disambiguation. Extensive experimental results demonstrate that the multi-class partial hinge loss significantly outperforms the state-of-the-art counterparts. [ABSTRACT FROM AUTHOR]

This paper investigates how the electromechanical response of MEMS/NEMS devices changes when the geometrical characteristics of their embedded flexural hinges are modified. The research is dedicated particularly to MEMS/NEMS devices which are actuated by means of rotary comb-drives. The electromechanical behavior of a chosen rotary device is assessed by studying the rotation of the end effector, the motion of the comb-drive mobile fingers, the actuator's maximum operating voltage, and the stress sustained by the flexure when the flexure's shape, length, and width change. The results are compared with the behavior of a standard revolute joint. Outcomes demonstrate that a linear flexible beam cannot perfectly replace the revolute joint as it induces a translation that strongly facilitates the pull-in phenomenon and significantly increases the risk of ruptures of the comb-drives. On the other hand, results show how curved beams provide a motion that better resembles the revolute motion, preserving the structural integrity of the device and avoiding the pull-in phenomenon. Finally, results also show that the end effector motion approaches most precisely the revolute motion when a fine tuning of the beam's length and width is performed. [ABSTRACT FROM AUTHOR]

This research focuses on the fabrication of plastic flexure hinges from diverse plastics such as ABS, PP, HDPE, and LDPE. To enhance hinge efficiency, the recycling ratios are also investigated. The amplification ratio of different recycle ratios and plastic types are measured. The results show that the input and output displacements of all PP, ABS, and HDPE hinges are linear. The presence of recycled plastics has no impact on this basis. The pure PP, ABS, and HDPE flexure hinges achieve the highest amplification ratios of 5.728, 8.249, and 5.668. The addition of recycled plastics reduces the amplification ratio. This decrease in the amplification ratio, however, is small. At a 25% recycle ratio, the PP, ABS, and HDPE flexure hinges have 12%, 13.3%, and 21.7% lower amplification ratios than the pure plastic hinges. Furthermore, the utilization of recycled plastics may lessen the need for new plastic made from raw materials. With the PP flexure hinge, a maximum input value of 157 µm could result in an output value of 886 µm. At a maximum input value of 115 µm, the ABS flexure hinge could achieve an output value of 833 µm. Finally, a maximum input value of 175 µm might result in an output value of 857 µm when using the HDPE flexure hinge. The average amplification ratio values for all recycling ratios for PP, ABS, and HDPE flexure hinges are, respectively, 5.35, 7.60, and 5.02. The ABS flexure hinge frequently outperforms the PP and HDPE flexure hinge in terms of amplification ratios. Among these plastics, HDPE flexure hinges have the lowest amplification ratio. In general, increasing the thermoplastic polyurethane (TPU) content of the LDPE/TPU blend increases the amplification ratio. The cause could be the TPU's high compatibility with the LDPE polymer. The LDPE/TPU blend hinge offers a broader range of the amplification ratio of 2.85–10.504 than the PP, ABS, and HDPE flexure hinges. It is interesting that changing the blend percentage has a much greater impact on the amplification ratio than changing the recycling ratio. The findings broaden the range of applications for plastic flexure hinges by identifying optimal plastic types. The impact of the hinge shape on the performance of the injected plastic flexure hinge might be studied in further research. [ABSTRACT FROM AUTHOR]

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In order to elucidate the effect of modification of the hinge region on structural polymorphism associated with conformational transitions, structural studies of hinge-modified oligopeptidase B from Serratia proteamaculans (SpOpBmod) in the crystalline state and solution were carried out. A new crystal structure of SpOpBmod in the intermediate conformation was obtained, and a molecular model of SpOpBmod in the open conformation was created using a combination of small-angle X-ray scattering with MD simulations. The improved electron density of the mobile H-loop carrying the catalytic H652 distinguished the obtained crystal structure from that which was previously reported. Good electron density in this region was previously found only in the inhibitor-bound SpOpBmod structure, in which one of the inhibitor molecules was covalently bound to H652. Comparison of the above structures of free and inhibitor-bound enzymes showed that both tertiary folds are the result of the internal conformational dynamics of SpOpBmod, which were captured by inhibitor binding. Comparison of the SpOpBmod structures with the structures of the same enzyme with a native hinge peptide made it possible to establish the influence of hinge modification on the rearrangement of the interdomain interface during conformational transitions. The above analysis also used models of native and hinge-modified enzymes in open conformations. We found that the interdomain interface observed in the crystal structures of hinge-modified enzymes could be considered an extreme version of the H-loop arrangement, in which closure of the domains does not lead to the assembly of the catalytic triad, whereas the intermediate conformation observed in the structure of the enzyme with the native hinge sequence illustrates a productive transition to the catalytically active closed conformation. [ABSTRACT FROM AUTHOR]

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We explore how the entropic notion of depletion forces between spheres, introduced by Asakura and Oosawa, can be extended to depletion torques that affect the orientations of colloidal particles having complex shapes. In prior experimental work, systems of microscale plate-like particles in the presence of a nanoscale depletion agent have been shown to form polymer-like columnar chains; restoring depletion torques act to align lithographically-structured platelets within a chain orientationally about the chain's axis. We consider depletion torques corresponding to parallel, face-to-face, near-contact pair interactions for complex-shaped, plate-like, prismatic lithographic particles in colloidal dispersions containing a spherical nanoscale depletion agent. We calculate depletion torques for a wide variety of such particles, including rotationally symmetric, asymmetric, achiral, chiral, and elongated particles. Moreover, we determine depletion torques between two non-parallel proximate square platelets connected by a lossless hinge along a common edge. Our investigations show that depletion torques can be tailored through lithographic or synthetic design of specific geometrical features in the shapes of particles. [ABSTRACT FROM AUTHOR]

This article discusses a case of dominant dystrophic epidermolysis bullosa pruriginosa (DDEB-Pr), a rare subtype of dystrophic epidermolysis bullosa (DEB) characterized by severe itching and prurigo-like lesions. The case involves a 28-year-old Japanese male with intractable prurigo-like lesions on his lower legs and dystrophic toenails. A skin biopsy confirmed the diagnosis of DDEB-Pr, and genetic analysis revealed a novel mutation in the COL7A1 gene. The article highlights the need for further research to understand the genotype-phenotype correlation and pathogenesis of DDEB-Pr. [Extracted from the article]

Motivated to bypass the twin basins of absolute relativism and dogmatic absolutism, an antinomic polarity into which thought tendentially falls, this paper offers various conceptual frameworks for overcoming antinomies in philosophical thought, and ultimately asserts that this overcoming occurs at a philosophical system's purported source: its active site of real genesis. The author traces a constellation of thinkers who all invoke this suspended thirdness in their own disciplinary and conceptual registers, from Jean Cavaillès to Gilles Châtelet, C.S. Peirce to Cécile Malaspina, ultimately and speculatively suggesting that this third space, the (abductive) hinge of real genesis, might precede and activate a priori the consequent diremptions into the polarities of the transcendental and the historical, the mathematical and the physical, the global and the local, the continuous and the discrete, the rational and the empirical, and so on. Such a genetic realism, then, places a radical exigency on philosophical thinking: to grasp its real genetic conditions, that is, without a previously given criterion or method. Ultimately, the paper is most interested in suggesting ways to reconfigure the conceptual landscape around this genetic tension or originating hinge, to encourage thought towards the genetic real and away from disciplinary stagnation, towards generative models for systematic thought itself. [ABSTRACT FROM AUTHOR]

The power exchange between fluid and structure plays a significant role in the force production and flight efficiency of flapping wings in insects and artificial flyers. This work numerically investigates the performance of flapping wings by using a high-fidelity fluid–structure interaction solver. Simulations are conducted by varying the hinge flexibility (measured by the Cauchy number, $Ch$ , i.e. the ratio between aerodynamic and torsional elastic forces) and the wing shape (quantified by the radius of the first moment of area, $\bar {r}_1$). Results show that the lift production is optimal at $0.05 and larger $\bar {r}_1$ where the minimum angle of attack is around $45^\circ$ at midstroke. The power economy is maximised for wings with lower $\bar {r}_1$ near $Ch=0.2$. Power analysis indicates that the optimal performance measured by the power economy is obtained for those cases where two important power synchronisations occur: anti-synchronisation of the pitching elastic power and the pitching aerodynamic and inertial powers and nearly in-phase synchronisation of the flapping aerodynamic power and the total input power of the system. While analysis of the kinematics for the different wing shapes and hinge stiffnesses reveals that the optimal performance occurs when the timing of pitch and stroke reversals are matched, thus supporting the effective transfer of input power from flapping to passive pitching and into the fluid. These results suggest that careful optimisation between wing shapes and hinge properties can allow insects and robots to exploit the passive dynamics to improve flight performance. [ABSTRACT FROM AUTHOR]

Coronavirus spike glycoproteins presented on the virion surface mediate receptor binding, and membrane fusion during virus entry and constitute the primary target for vaccine and drug development. How the structure dynamics of the full-length spikes incorporated in viral lipid envelope correlates with the virus infectivity remains poorly understood. Here we present structures and distributions of native spike conformations on vitrified human coronavirus NL63 (HCoV-NL63) virions without chemical fixation by cryogenic electron tomography (cryoET) and subtomogram averaging, along with site-specific glycan composition and occupancy determined by mass spectrometry. The higher oligomannose glycan shield on HCoV-NL63 spikes than on SARS-CoV-2 spikes correlates with stronger immune evasion of HCoV-NL63. Incorporation of cryoET-derived native spike conformations into all-atom molecular dynamic simulations elucidate the conformational landscape of the glycosylated, full-length spike that reveals a role of hinge glycans in modulating spike bending. We show that glycosylation at N1242 at the upper portion of the stalk is responsible for the extensive orientational freedom of the spike crown. Subsequent infectivity assays implicated involvement of N1242-glyan in virus entry. Our results suggest a potential therapeutic target site for HCoV-NL63. In this work, the authors combine cryo-electron tomography of vitrified virions, mass spectrometry, modeling, molecular dynamics and infectivity assay and report that a hinge glycan on viral spike protein influences virus infection and immune evasion. [ABSTRACT FROM AUTHOR]

The flavivirus envelope protein is a class II fusion protein that drives flavivirus-cell membrane fusion. The membrane fusion process is triggered by the conformational change of the E protein from dimer in the virion to trimer, which involves the rearrangement of three domains, EDI, EDII, and EDIII. The movement between EDI and EDII initiates the formation of the E protein trimer. The EDI-EDII hinge region utilizes four motifs to exert the hinge effect at the interdomain region and is crucial for the membrane fusion activity of the E protein. Using West Nile virus (WNV) NY99 strain derived from an infectious clone, we investigated the role of eight flavivirus-conserved hydrophobic residues in the EDI-EDII hinge region in the conformational change of E protein from dimer to trimer and viral entry. Single mutations of the E-A54, E-I130, E-I135, E-I196, and E-Y201 residues affected infectivity. Importantly, the E-A54I and E-Y201P mutations fully attenuated the mouse neuroinvasive phenotype of WNV. The results suggest that multiple flavivirus-conserved hydrophobic residues in the EDI-EDII hinge region play a critical role in the structure–function of the E protein and some contribute to the virulence phenotype of flaviviruses as demonstrated by the attenuation of the mouse neuroinvasive phenotype of WNV. Thus, as a proof of concept, residues in the EDI-EDII hinge region are proposed targets to engineer attenuating mutations for inclusion in the rational design of candidate live-attenuated flavivirus vaccines. [ABSTRACT FROM AUTHOR]

Mammalian fertilization is a species-selective event that involves a series of interactions between sperm proteins and the oocyte's zona pellucida (ZP) glycoproteins. Bovine ZP consists of three glycoproteins: bZP2, bZP3, and bZP4. In our previous study, we demonstrated that bovine sperm binds to plastic wells coated with recombinant bZP4 and identified that the N-terminal domain and the middle region of bZP4 are critical for sperm-binding activity. Here, we investigated the sperm-binding site in the middle region (residues 290 to 340) of bZP4, which includes the hinge region. We showed that bovine sperm binds to bZP4's middle region in a species-selective manner. We mapped the function of bZP4's middle region to its N-glycosylation site at Asn-314 using several recombinant mutated proteins. Moreover, we showed that mutations of the N-glycosylation sites at Asn-314 close to the hinge region and Asn-146 of the hinge region of bZP4 and bZP3, respectively, reduced the sperm-binding activity of the complex of the bZP3 (from 32 to 178) and bZP4 (from 136 to 464) fragments. Together, these results suggest that ZP's middle regions of bZP3 and bZP4 form one of the sperm-binding sites of bovine ZP. [ABSTRACT FROM AUTHOR]

Deployable structures composed of hinge joints (revolute joints) with inclined axis have a potential to realize a rich variety of deformation with a small number of members, which enables it to be lightweight with low risk of failure. In this article, a systematic method is proposed to obtain new hinge-jointed structures that have N-dihedral symmetry and can be folded into a straightly bundled shape. The proposed structure, which we call N-gonal multilayer symmetric revolute linkage (N-MLSRL), is composed of some layers. Each layer is an assemblage of 2N bars and 2N inclined hinges, which can be deformed from a regular 2N-gonal frame into an entirely straight rod shape, which is a generalization of a 4-bar Bennett linkage. For the case N is less than or equal to 3, the N-MLSRL has a single degree-of-freedom. For an application to design of deployable structures, a method is introduced to generate the structure expanded to a predefined target surface of revolution. For designing the realistic detail considering the finite sizes of the joints, a technique called hinge offsets is used. The proposed method is applied to a horn-shaped structure, a ball-shaped structure, and a dome-shaped structure as its numerical examples. The validity of the proposed method is confirmed by a physical model of a dome-shaped structure including hinge offsets. [ABSTRACT FROM AUTHOR]

Wouter Kusters argues that madness has much to offer philosophy, as does philosophy to madness. In this paper, I support both claims by drawing on a mad phenomenon which I label Radical Psychotic Doubt, or RPD. First, although skepticism is a minority position in epistemology, it has been claimed that anti-skeptical arguments remain unsatisfying. I argue that this complaint can be clarified and strengthened by showing that anti-skeptical arguments are irrelevant to RPD sufferers. Second, there's a debate about whether so-called hinge commitments are beliefs or not. I argue that RPD can be used to strengthen the case that they are. Moreover, if hinges are beliefs, some madpeople are more epistemically rational than some sane philosophers. Third, drawing on my own mad experiences, I challenge evidentialism by presenting a better candidate for a truly forced choice about what to believe than William James' traditional religious example. I further show that in certain psychiatric contexts, evidentialism has more radical implications than Jamesian pragmatism, which comes out as more conservative. Finally, I discuss how philosophical theories like pragmatism and Pyrrhonism can provide inspiration for new and much – needed coping strategies for RPD sufferers. [ABSTRACT FROM AUTHOR]

Analytical equations that describe the dynamic behavior of beams with a soft clamped end are very little treated in the literature. The paper aims to solve this problem by introducing a stiffness in the hinged end of the beam, respectively by comparing the bending moment in the clamped end with the slope in the hinge of the same end of the beam. The other end of the beam is permanently hinged. The characteristic equation for determining the eigenvalues and the modal function is deduced. The results show the first four vibration modes for seven stiffness values and the eigenvalues for eleven cases of soft clamped end. [ABSTRACT FROM AUTHOR]

Purpose: To examine the association between the hinge position, fibular head position, and type III lateral hinge fracture (LHF) in patients with knee osteoarthritis (OA) who underwent medial open wedge high tibial osteotomy (MOWHTO). Methods: This retrospective study examined patients who underwent MOWHTO. Radiographically, the Kellgren–Lawrence (K/L) classification, distance between the articular surface and the tip of the fibular head (fibular head position), hinge point (hinge position), type of LHF, and safe zone (within the proximal tibiofibular joint) outlier were evaluated. To determine the cut-off value of the hinge position and fibular head position associated with type III LHF, a receiver operating characteristic (ROC) curve analysis was performed. The odds ratio (OR) was calculated from the obtained cut-off values using logistic regression, which was adjusted by age, gender, body mass index, and opening distance. Results: Among 132 knees in 120 patients, the radiographic severity of knee OA was 19 (14%), 73 (55%), and 40 (30%) of K/L grades 2, 3, and 4, respectively. LHF was observed in 40 knees (30%), including types I, II, and III fractures in 21 (16%), 5 (4%), and 14 (11%) knees, respectively. Hinge and fibular head positions were 16 and 10 mm, respectively, with significant correlation. Safe zone outlier was observed in 38 knees (29%). The hinge and fibular head positions with type III LHF were significantly higher (more cranial) than those with no fracture or other LHF subtypes. The ROC curve revealed that the cut-off value for the hinge and fibular head positions was 13.3 and 8.6 mm, respectively. The OR of the hinge and fibular head positions was 22.42 and 13.86, respectively. Conclusions: A higher hinge position was a risk factor for type III LHF and was associated with a higher fibular head in patients with knee OA who underwent MOWHTO. The hinge position should be placed at a certain distance from the articular surface to avoid type III LHF, especially in participants with higher fibular head position, even if the hinge position is located in the safe zone. Level of evidence: Retrospective cohort study, Level III. [ABSTRACT FROM AUTHOR]

Competitive divers are able to attain much higher scores when they perform a splash-less entry. To achieve this goal, they use the "rip" entry maneuver where they roll their body forward immediately after impact. This dynamic shape change after impact separates them from previously studied entry bodies. An experimental study of a geometrically simplified hinged diver model is presented. The results for five different hinged models are reported. Geometric and hinge stiffness changes are used to identify the most important aspects of the maneuver. The trajectory of these models after impact and the estimated size of the entrained air cavity are reported. The models that deform the fastest also have the largest final estimated air cavity. A non-dimensional time based on the time to complete deformation is found to collapse the estimated size of the air cavity for all models that deform before the trailing air cavity collapses. Fixed models are introduced to compare the hinged models to non-deforming entry bodies. The hinged models are found to have between 42% and 154% larger estimated air cavities during the final measurement than their fixed counterpart. At the moment of deep seal, two distinct air cavities are formed: one that connects to the atmosphere above the pool that has smooth walls and a lower cavity largely composed of small bubbles. This composition is analogous to observations of competitive divers. Entry bodies that deform are found to significantly change the shape and formation of the air cavity. [ABSTRACT FROM AUTHOR]

Steel special moment frames (SMFs) with built-up box columns and I-shaped beams commonly are used for seismic design, especially in Asian countries. Modern seismic design codes assume that plastic hinging will occur near the base of columns and in the reduced beam section (RBS) region; a strong column–weak beam (SCWB) check is required to reduce the likelihood that column hinging will occur above the first story. This study investigated the effects of column section compactness (i.e., width–thickness ratio), axial force level, and SCWB ratio on the moment redistribution and plastic hinging in the bottom two stories of the columns. Two half-scale, two-and-one-half-story subassemblages with a column and RBS beams were cyclically tested; steel beams were included to simulate a realistic boundary condition to the column, especially after the beams started to form plastic hinges. The experimental observations of two subassemblages with varying column width–thickness ratios and SCWB ratios showed that meeting the SCWB requirement does not necessarily preclude plastic hinging in the second-story column. A finite-element parametric study with nine subassemblage models was conducted. A design criterion with an expression containing both the width–thickness and SCWB ratios is proposed to achieve plastic hinging near the column base, but not elsewhere along the columns. [ABSTRACT FROM AUTHOR]

For a long time, it was believed that Alfred Kempe proved (1876) a theorem about the possibility of plotting an arbitrary planar algebraic curve by parts using hinge mechanisms (linkages). However, at the end of the 20th century, specialists in algebraic geometry, having rediscovered and developed this result in modern language, began to assert that Kempe's reasoning contained significant gaps and errors. In the author's opinion, these claims are unfounded. In this paper, by a detailed analysis of the notions of a linkage and its configuration space, the author tries to substantiate this point of view. [ABSTRACT FROM AUTHOR]

Beam–column connection zones are high regions of interest in reinforced concrete (RC) structures, which are expected to respond elastically to seismic loads. Using carbon fiber-reinforced polymers (CFRP) to improve these connections, performance is critical in retrofitting deficient RC frames because existing slabs may pose numerous limitations in the design and wrapping of CFRP sheets in joints. The main aim of this research is to develop a new design for flange-bonded CFRP retrofit of frames, including slabs, for the relocation of plastic hinges of the connection area toward the beam and to develop beam–column joint capacity and building stability in cases of subjection to dynamic loads. The performance of these proposed retrofittings was explored both experimentally and numerically. Two full-scale fabricated interior RC joints of a real moment-resisting frame with moderate ductility were subjected to monotonic loads before and after retrofitting, and the results were used to detail the numerical progress and verify of the beam–column connection. Moreover, a parametric study was conducted on CFRP sheets' optimal thickness to examine its influence on plastic hinge relocation in the connection region. Results show that the retrofitting method can efficiently relocate the plastic hinge to the mid-span of the beam, which, in turn, leads to improved capacity and achievement of the RC frame and guarantees better structural safety a lower cost. [ABSTRACT FROM AUTHOR]

Middle Jurassic terebratulide brachiopods from the Jordan Valley are herein described and a new taxon is added to the previous faunal list. The Callovian rocks (Mughanniyya Formation) of the Tel el Dhahab section have yielded the following terebratulide taxa: Sphriganaria capax, S. costata, S. costellata, S. curtirostra, S. expansa, S. irregularis, S. subcircularis, S. nasuta, S. sp. 1, and S.? sp. 2. A new species Sphriganaria anyamiae sp. nov. is formally described herein. Internal characters of Sphriganaria costata, S. expansa, and S. nosuta have been studied. On the basis of shell microstructure, crural bases, outer and inner hinge plates were differentiated and defined for the first time in the genus Sphriganaria. The secondary layer is homogeneous built of very fine fibres, predominantly anisometric-like in cross-section, 25‒40 μm wide and 8‒15 μm thick. The Callovian Mughanniyya Formation of northwest Jordan is dominated by highly fossiliferous limestones intercalated with marlstone beds with very diverse brachiopod fauna, deposited in shallow, low-energy waters very near the equator. A paleobiogeographic interpretation of the brachiopod faunas in the Ethiopian Province suggests that brachiopods migrated from the north in the Early Jurassic and later became isolated for the remainder of the period. [ABSTRACT FROM AUTHOR]