Terms Of Kinematics Research Articles

An Independent Measure of the Kinematic Dipole from SDSS

We utilize the Sloan Digital Sky Survey (SDSS) extended Baryon Oscillation Spectroscopic Survey and Baryon Oscillation Spectroscopic Survey catalogs with precise spectroscopic redshifts to estimate the kinematic redshift dipole caused by the proper motion of the solar system. We find that the velocity extracted from the kinematic dipole is consistent with cosmic microwave background (CMB) inferred values. Although the small sky coverage and limited number density of the SDSS sources constrain us from obtaining precise and robust measurements, we leverage the redshift dipole method to estimate the kinematic dipole. The velocity measurements in this study are insensitive to intrinsic clustering, associated with the source count dipole. The kinematic dipole measured in this work and its consistency with CMB values do not guarantee isotropy at large scales. The anisotropy (excess dipole) measured with the NRAO VLA Sky Survey and the Wide-field Infrared Survey Explorer Catalog could be due to the intrinsic distribution of galaxies. The results in this work focus solely on the kinematic dipole term.

QTL for the Kinematic Traits That Define the Arabidopsis Root Elongation Zone and Their Relationship to Gravitropism.

Cell expansion in a discrete region called the elongation zone drives root elongation. Analyzing time lapse images can quantify the expansion in kinematic terms as if it were fluid flow. We used horizontal microscopes to collect images from which custom software extracted the length of the elongation zone, the peak relative elemental growth rate (REGR) within it, the axial position of the REGR peak, and the root elongation rate. Automation enabled these kinematic traits to be measured in 1575 Arabidopsis seedlings representing 162 recombinant inbred lines (RILs) derived from a cross of Cvi and Ler ecotypes. We mapped ten quantitative trait loci (QTL), affecting the four kinematic traits. Three QTL affected two or more traits in these vertically oriented seedlings. We compared this genetic architecture with that previously determined for gravitropism using the same RIL population. The major QTL peaks for the kinematic traits did not overlap with the gravitropism QTL. Furthermore, no single kinematic trait correlated with quantitative descriptors of the gravitropism response curve across this population. In addition to mapping QTL for growth zone traits, this study showed that the size and shape of the elongation zone may vary widely without affecting the differential growth induced by gravity.

Microstructural effects and constitutive modelling of cyclic softening behaviour in Ti–6Al–4V titanium alloys

Cyclic softening in Ti–6Al–4V titanium alloy significantly influences the reliability and performance of critical engineering components. This study addresses the lack of a comprehensive understanding of cyclic softening in different microstructures of Ti–6Al–4V titanium alloys. Microstructures with bimodal and lamellar morphologies were prepared by heat treatment of Ti–6Al–4V titanium alloy at various temperatures. Interrupted low-cycle fatigue tests revealed a larger cyclic softening for the bimodal microstructures than the lamellar microstructures. Finite element analysis (FEA) captured the cyclic softening by incorporating the Voce isotropic hardening model with the Chaboche kinematic hardening model. Two nonlinear kinematic hardening terms, along with the Voce isotropic hardening model whose parameters were calculated using the variation in cyclic yield strength and cyclic stress amplitude resulted in good prediction for bimodal and lamellar microstructures, respectively. The accuracy of the model is further improved when a linear kinematic term is added to it. Transmission electron microscope, electron backscatter diffraction, and energy dispersive spectroscopy analysis revealed that the extensive softening in the bimodal microstructure is associated with the dislocation localization in the primary alpha (αp) leading to a considerable plastic strain accumulation and subsequent crystal re-orientation. The alloying element partitioning, lamella width, and the ease of slip transmission at the secondary alpha (αs) and beta (β) interface also play essential roles in the cyclic softening.

Physics-driven neural networks for nonlinear micromechanics

Micromechanical problems seek full-field solutions in response to external and/or internal thermal-mechanical loads, which have been increasingly encountered in material property and process assessments. Here we present a machine learning based strategy of solving micromechanics at finite strains. Deep neural networks (DNNs) are trained by employing the elastic energy together with other physical constraints to formulate the loss function. In particular, the crossover of material points, which can be a common issue for similar DNNs when applied to compression-dominant problems, is shown to be effectively addressed by including a kinematic penalty term that forces the DNN to maintain structural integrity and stability and avoid unphysical behavior. The generality and accuracy of the proposed physics-driven neural networks (PDNNs) are demonstrated through various micromechanical problems, including single crystal anisotropy elasticity, Eshelby's inclusion problem, buckling, and elastic homogenization of polycrystals. The effect of the choice of optimizers and hyperparameters on the PDNN training are discussed and the computational efficiency is also analyzed. It is shown that this novel PDNN framework can completely remove the need of labeled training data and exhibit improved performances as compared to the conventional physics-informed neural networks (PINNs) in terms of avoiding unphysical solutions and attaining higher computational efficiency. PDNNs can thus serve as a promising tool to solve some critical challenges associated with a wide range of nonlinear micromechanical problems.

Curved non-motorized treadmills do not biomechanically replicate overground running better than motorized treadmills

ABSTRACT The purpose of this study was to determine if curved non-motorized treadmills can reproduce overground running better than motorized treadmills by analysing the differences in joint kinematics (hip, knee, and ankle) using SPM. Nineteen recreational runners completed three randomized running tests on these surfaces. Kinematic data from the hip, knee, and ankle joints were collected. Two-tailed SPM t-tests were performed to analyse time-continuous gait cycles in three anatomical planes of each joint. Higher within-subject variability was observed in the frontal and transverse planes during curved non-motorized treadmill running. SPM analysis showed more significant differences (p < 0.05) between curved non-motorized treadmill and overground than between motorized treadmill and overground, mainly in knee (from 12% to 30% and 93% to 99% of the gait cycle) and ankle (from 19% to 23% of the gait cycle) in the sagittal plane. Therefore, running on curved non-motorized treadmills is more biomechanically different compared to overground than motorized treadmills, and might not be the best strategy to replicate overground running in terms of joint kinematics during highly controlled research studies. However, they could be an interesting tool in rehabilitation or training environments since the changes observed in joint kinematics were likely not functionally relevant.

Human movement modifications induced by different levels of transparency of an active upper limb exoskeleton.

Active upper limb exoskeletons are a potentially powerful tool for neuromotor rehabilitation. This potential depends on several basic control modes, one of them being transparency. In this control mode, the exoskeleton must follow the human movement without altering it, which theoretically implies null interaction efforts. Reaching high, albeit imperfect, levels of transparency requires both an adequate control method and an in-depth evaluation of the impacts of the exoskeleton on human movement. The present paper introduces such an evaluation for three different "transparent" controllers either based on an identification of the dynamics of the exoskeleton, or on force feedback control or on their combination. Therefore, these controllers are likely to induce clearly different levels of transparency by design. The conducted investigations could allow to better understand how humans adapt to transparent controllers, which are necessarily imperfect. A group of fourteen participants were subjected to these three controllers while performing reaching movements in a parasagittal plane. The subsequent analyses were conducted in terms of interaction efforts, kinematics, electromyographic signals and ergonomic feedback questionnaires. Results showed that, when subjected to less performing transparent controllers, participants strategies tended to induce relatively high interaction efforts, with higher muscle activity, which resulted in a small sensitivity of kinematic metrics. In other words, very different residual interaction efforts do not necessarily induce very different movement kinematics. Such a behavior could be explained by a natural human tendency to expend effort to preserve their preferred kinematics, which should be taken into account in future transparent controllers evaluation.

RFWBS Model: Multilevel Hybrid Mapping Solution Framework for Designing Neurorehabilitation Physiotherapy Devices

Healthcare services and rehabilitation equipment have entered a phase of rapid development driven by user requirements. However, the development of corresponding design models for rehabilitation equipment is lacking. A general framework and development process are urgently needed for neurorehabilitation physiotherapy equipment. To address problems such as inadequate knowledge representation in the design process and difficulties in modeling the functional structure of the product, we combined a decomposition topology model of neurorehabilitation physiotherapy equipment with the modular design method. We proposed a general model for the design of neurorehabilitation physiotherapy equipment comprising the following modules: requirements (R), function (F), principle workspace (W), behavior (B), and structure (S), i.e., the RFWBS model. Using the neurorehabilitation robotic glove as an example for design practice, in terms of kinematics, the mechanism is analyzed by establishing a Lagrangian coordinate system for resolution. The mechanism has three degrees of freedom and can achieve the natural flexion and extension angles of each finger joint. In terms of dynamics, during the entire finger extension, the angular acceleration is almost zero, and the average angular velocity is approximately 30~50°/s. This indicates that the mechanism is suitable for wearable use, validating the scientific and effective nature of the RFWBS expanded model.

Patch Track Software for Measuring Kinematic Phenotypes of Arabidopsis Roots Demonstrated on Auxin Transport Mutants.

Plant roots elongate when cells produced in the apical meristem enter a transient period of rapid expansion. To measure the dynamic process of root cell expansion in the elongation zone, we captured digital images of growing Arabidopsis roots with horizontal microscopes and analyzed them with a custom image analysis program (PatchTrack) designed to track the growth-driven displacement of many closely spaced image patches. Fitting a flexible logistics equation to patch velocities plotted versus position along the root axis produced the length of the elongation zone (mm), peak relative elemental growth rate (% h-1), the axial position of the peak (mm from the tip), and average root elongation rate (mm h-1). For a wild-type root, the average values of these kinematic traits were 0.52 mm, 23.7% h-1, 0.35 mm, and 0.1 mm h-1, respectively. We used the platform to determine the kinematic phenotypes of auxin transport mutants. The results support a model in which the PIN2 auxin transporter creates an area of expansion-suppressing, supraoptimal auxin concentration that ends 0.1 mm from the quiescent center (QC), and that ABCB4 and ABCB19 auxin transporters maintain expansion-limiting suboptimal auxin levels beginning approximately 0.5 mm from the QC. This study shows that PatchTrack can quantify dynamic root phenotypes in kinematic terms.

Cerium oxide nanoparticles improve the post-thaw quality and in-vivo fertility of Beetal buck spermatozoa

The motility, health quality, and membrane disorders of spermatozoa are adversely affected during the process of semen cryopreservation due to the over-production of reactive oxygen species (ROS). Cerium oxide nanoparticles (CeO2NPs) possess properties to scavenge ROS either by mimicking specific antioxidants or by enhancing the activities of antioxidant enzymes. Therefore, we aimed at evaluating the effects of adding the CeO2NPs in the TRIS-citrate-yolk extender on in-vitro antioxidant enzyme activities, spermatozoa quality attributes, and in-vivo fertility of post-thaw Beetal buck spermatozoa. The CeO2NPs were prepared and characterized (UV-spectrophotometry, FTIR, and XRD). Semen samples, collected from bucks (n = 5), were distributed into five aliquots and diluted in an extender containing increasing concentrations of nanoparticles (0 μg/ml, called the control group, 25 μg/mL, 50 μg/mL, 75 μg/mL, and 100 μg/mL). At post-thaw, spermatozoa were evaluated for the above-mentioned attributes and the pregnancy rate by inseminating Beetal does (n = 252). Results demonstrated that CeO2NPs mitigated the detrimental effects of cryopreservation as ROS production and lipid peroxidation were lower (P < 0.001) in the 25, 50, and 75 μg/mL CeO2NPs-added groups compared to the control and 100 μg/ml CeO2NPs-added group. The addition of 25 μg/mL CeO2NPs improved (P < 0.001) the activities of superoxide dismutase, catalase, and peroxidase and the concentration of reduced glutathione (P < 0.001) compared to the other groups. In terms of sperm kinematics and velocity parameters, the groups added with the 25 and 50 μg/mL CeO2NPs exhibited higher total motility (P < 0.001), sperm progressive motility (P = 0.003), and rapid velocity (P < 0.001). The group added with the 50 μg/mL CeO2NPs had the highest (P = 0.04) average path velocity. The groups added with the 25 and 50 μg/mL CeO2NPs also exhibited higher plasma membrane integrity (P = 0.003), acrosomal integrity, and viability (P < 0.001) compared to the control group. The DNA integrity was also higher (P < 0.001) in all the CeO2NPs-added groups. The pregnancy rate was higher (P = 0.003) in the 25 (51.92 %) and 50 μg/mL CeO2NPs (58.33 %) groups compared to the other groups. Conclusively, our findings suggest that the inclusion of cerium oxide nanoparticles in the TRIS-citrate-yolk freezing extender can reduce the occurrence of cryopreservation-induced damages to Beetal's buck spermatozoa and ultimately enhance the pregnancy rate in does.

Dissociating the contributions of sensorimotor striatum to automatic and visually guided motor sequences.

The ability to sequence movements in response to new task demands enables rich and adaptive behavior. However, such flexibility is computationally costly and can result in halting performances. Practicing the same motor sequence repeatedly can render its execution precise, fast and effortless, that is, 'automatic'. The basal ganglia are thought to underlie both types of sequence execution, yet whether and how their contributions differ is unclear. We parse this in rats trained to perform the same motor sequence instructed by cues and in a self-initiated overtrained, or 'automatic,' condition. Neural recordings in the sensorimotor striatum revealed a kinematic code independent of the execution mode. Although lesions reduced the movement speed and affected detailed kinematics similarly, they disrupted high-level sequence structure for automatic, but not visually guided, behaviors. These results suggest that the basal ganglia are essential for 'automatic' motor skills that are defined in terms of continuous kinematics, but can be dispensable for discrete motor sequences guided by sensory cues.

Examining the gait pattern in terms of spatio-temporal, kinematic and kinetic parameters during gait initiation in MS patients

Examining the gait pattern in terms of spatio-temporal, kinematic and kinetic parameters during gait initiation in MS patients

Hybrid thrust sequences – A new structural perspective

Thrust sequences show a range of geometric and kinematic characteristics in cross-sections and in map view. Two types of thrust sequences are commonly observed in thrust systems – forward-breaking and break-back thrust sequences. For nearly half a century, it has been hypothesized that forward-breaking and break-back thrust sequences represent end-members of a continuous spectrum of brittle and ductile structures. Many natural and experimental observations of transitional thrust sequences display both forward-breaking and break-back (hybrid) thrust sequences within the same thrust system. An explanation of hybrid thrust sequence development has neither been provided conceptually nor experimentally. We present geometric and kinematic results of natural observations and numerical experiments that show a transition from forward-breaking to break-back thrust sequences caused by the effects of stratigraphic variations, sedimentary environment, surface processes, critical-wedge effects, progressive deformation with an increase in compressive stress, presence of detachments and their frictional properties, and strain rate. We also discuss numerous geometric, kinematic, chronological and mechanical criteria to identify the characteristic signatures of hybrid thrust sequences. This study provides a template to distinguish different thrust sequences and to characterize the deformation conditions under which hybrid thrust sequences develop in contractional settings. Mechanical and field criteria, displacement patterns imaged on seismic reflection sections across onshore and offshore thrust systems, and the way that thrusts interact in terms of geometry, kinematics and strain, are used to illustrate thrust development.

Dynamic behaviour of multi-stage crash energy absorption systems integrated with MRA: Simulation and analysis

The research work focuses on development of mathematical models to study on the dynamic behaviour of a multi-stage crash energy absorption system (MSCEAS) suitable for cars. The proposed energy absorption system can be attached in the front overhang of the vehicle, which comprises of a bumper, magneto-rheological absorber (MRA), friction spring, and piston-cylinder with shear plate assembly (PCSPA).11MSCEAS - Multi-stage crash energy absorption system, MRA-Magneto-rheological absorber, PCSPA-Piston-cylinder with shear plate assembly, LPM- Lumped parameter model, DoF-Degrees of freedom, MBWM-Modified Bouc–Wen model. These components are arranged in series where in, MRA plays a vital role as it transforms passive system in to semi-active. The entire system has been characterized as lumped parameter model (LPM). The real-time crash test of Dodge-Neon vehicle is utilized to create the base model with four degrees of freedom (DoF) LPM and parameters including mass, stiffness, and damping coefficient are chosen based on vehicle’s structural components. The MRA has been modelled based on modified Bouc–Wen model (MBWM) and the optimized parameters are selected from existing literature while considering the high damping capability of MRA. Four models have been proposed by interchanging the energy absorbing elements so as to obtain the best configuration in terms of crash kinematics. Numerical analysis is performed for both base vehicle and vehicle assembled with the proposed models based on crash kinematics of occupant’s cabin. It is found that, one among the four models exhibit appreciable reduction in intrusion displacement during low to high-speed collisions. Whereas, another proposed model exhibits considerable decrement in deceleration patterns. Further, behaviour of four absorption elements has also been captured for various impact speeds and voltages supplied to MRA and presented in this work. The current research is carried out to protect the occupants from dangerous vehicle crashes by integrating a MSCEAS based on MRA as a critical add-on.

Transverse Dinaric zone of increased compression between the Kraški rob and Hrušica Regions, NE Microadria

The Kvarner fault divides the Microadria (Adria microplate, the Adria stable core) into the Po and Adria segments. The Istra block, which is sandwiched between the right-lateral Kvarner Fault and the left-lateral Sistiana Fault lies at the extreme eastern edge of the Po segment. Both faults run transversely to the Dinarides and reach their thrust boundary in the east. The Microadria has been moving towards the Dinarides since the Middle Miocene. The movement of the Istra block is exposed in relation to the neighbouring blocks, so an extensive pushed area (the Istra Pushed Area) was formed in the External Dinarides, which is bent towards the northeast. It is defined by two flexural zones, one lying in the extension of the Sistiana Fault and the other in the extension of the Kvarner Fault. The structure of the Dinaric thrust border on the north-eastern side of the Istra block is complex. Its prominent structural element is the Črni Kal Anomaly, due to which a zone of increased compression developed within the Istra Pushed Area and transversely to the Dinarides (Kraški rob – Hrušica Traverse), which lies between the Sistiana and Kvarner Flexural Zones. In terms of kinematics, it differs greatly from these two, and various geomorphologically responsive deformations have occurred within it. Mt. Vremščica (1027 m), which represents a transpressive anticline within the wider zone of the Raša Fault is the most prominent. In order to understand the genesis of the Classical Karst relief, it is important to know that the Mt. Vremščica ridge rose from the levelled karst surface.

Rejuvenating Star Formation Activity in an Early-type Dwarf Galaxy, LEDA 1915372, with Accreted H i Gas

We report a rare astrophysical phenomenon, in which an early-type dwarf galaxy (dE), LEDA 1915372, is accreting gas from a nearby star-forming dwarf galaxy, MRK 0689, and is rejuvenating star formation activity at the center. Both LEDA 1915372 and MRK 0689 have similar brightness of M r = −16.99 and −16.78 mag, respectively. They are located in a small group environment, separated by a sky-projected distance of 20.27 kpc (up to 70 kpc in three dimension), and have a relative line-of-sight radial velocity of 6 km s−1. The observation of 21 cm emission with the Giant Metrewave Radio Telescope provides strong evidence of interaction between the pair of dwarf galaxies in terms of neutral hydrogen (Hi) morphology and kinematics. In particular, the Hi map reveals that the two galaxies are clearly connected by a gas bridge, and the gas components of both LEDA 1915372 and MRK 0689 share a common direction of rotation. We also find that the Hi emission peak deviates from LEDA 1915372 toward its optical blue plume, suggesting a tidal origin of ongoing central star formation. Our findings provide a new path to the formation of blue-cored dEs.

{B}_c^{-}to J/psi left(to {mu}^{+}{mu}^{-}right){tau}^{-}left(to {pi}^{-}{nu}_{tau },{rho}^{-}{nu}_{tau },{ell}^{-}{overline{nu}}_{ell }{nu}_{tau}right){overline{nu}}_{tau } decays with visible final-state kinematics

The semitauonic {B}_c^{-}to J/psi {tau}^{-}{overline{nu}}_{tau } decay provides an ideal and clean mode to scrutinize possible new physics effects in bto c{tau}^{-}{overline{nu}}_{tau } transitions as indicated by the current data on R(D(*)) anomalies. In this work, we use the spin density matrix method to obtain the maximum information on the underlying physics of {B}_c^{-}to J/psi {tau}^{-}{overline{nu}}_{tau } decay with both polarized τ lepton and J/ψ meson. Their subsequent decays, with J/ψ → μ+μ− as well as τ− → π−ντ, τ− → ρ−ντ and {tau}^{-}to {ell}^{-}{overline{nu}}_{ell }{nu}_{tau } , are exploited to extract the energy and angular distributions of the charged final-state particles in the processes. Starting with the most general effective Hamiltonian relevant for the bto c{tau}^{-}{overline{nu}}_{tau } transitions, including all possible Lorentz structures of the dimension-six operators with both left- and right-handed neutrinos, we first derive the five-fold differential decay rate in terms of the visible final-state kinematics. From this distribution, we then construct in total 34 normalized observables, among which nine refer to the CP-violating triple product asymmetries that vanish within the Standard Model. We also construct five new observables based on the combinations of these normalized observables that can only be attributed to the right-handed neutrinos. On the other hand, considering the low statistics of the fully differential distribution, we introduce some integrated observables with only one kinematic variable left, which are more promising to be measured due to the largely increased statistics. The sensitivities of all these observables to the different new physics scenarios are investigated in detail. Finally, assuming an ideal circumstance, we give an estimate of the statistical uncertainties of the nine CP-conserving observables at LHCb and found that τ− → π−ντ has the highest analyzing power among the three τ decay channels.

Forward and Backward Walking: Multifactorial Characterization of Gait Parameters

Although extensive literature exists on forward and backward walking, a comprehensive assessment of gait parameters on a wide and homogenous population is missing. Thus, the purpose of this study is to analyse the differences between the two gait typologies on a relatively large sample. Twenty-four healthy young adults participated in this study. By means of a marker-based optoelectronic system and force platforms, differences between forward and backward walking were outlined in terms of kinematics and kinetics. Statistically, significant differences were observed in most of the spatial–temporal parameters, evidencing some adaptation mechanisms in backward walking. Differently from the ankle joint, the hip and knee range of motion was significantly reduced when switching from forward to backward walking. In terms of kinetics, hip and ankle moment patterns for forward and backward walking were approximately mirrored images of each other. Moreover, joint powers appeared drastically reduced during reversed gait. Specifically, valuable differences in terms of produced and absorbed joint powers between forward and backward walking were pointed out. The outcomes of this study could represent a useful reference data for future investigation evaluating the efficacy of backward walking as a rehabilitation tool for pathological subjects.

A Trade-Off between Complexity and Interaction Quality for Upper Limb Exoskeleton Interfaces.

Exoskeletons are among the most promising devices dedicated to assisting human movement during reeducation protocols and preventing musculoskeletal disorders at work. However, their potential is currently limited, partially because of a fundamental contradiction impacting their design. Indeed, increasing the interaction quality often requires the inclusion of passive degrees of freedom in the design of human-exoskeleton interfaces, which increases the exoskeleton's inertia and complexity. Thus, its control also becomes more complex, and unwanted interaction efforts can become important. In the present paper, we investigate the influence of two passive rotations in the forearm interface on sagittal plane reaching movements while keeping the arm interface unchanged (i.e., without passive degrees of freedom). Such a proposal represents a possible compromise between conflicting design constraints. The in-depth investigations carried out here in terms of interaction efforts, kinematics, electromyographic signals, and subjective feedback of participants all underscored the benefits of such a design. Therefore, the proposed compromise appears to be suitable for rehabilitation sessions, specific tasks at work, and future investigations into human movement using exoskeletons.

CALIBRATION OF HOLZAPFEL-GASSER-OGDEN COLLATERAL LIGAMENT PROPERTIES IN A HYBRID POST-ARTHROPLASTY KNEE JOINT MODEL FOR LAXITY TESTING

This study aims to create a novel computational workflow for frontal plane laxity evaluation which combines a rigid body knee joint model with a non-linear implicit finite-element model wherein collateral ligaments are anisotropically modelled using subject-specific, experimentally calibrated Holzpfel-Gasser-Ogden (HGO) models.The framework was developed based on CT and MRI data of three cadaveric post-TKA knees. Bones were segmented from CT-scans and modelled as rigid bodies in a multibody dynamics simulation software (MSC Adams/view, MSC Software, USA). Medial collateral and lateral collateral ligaments were segmented based on MRI-scans and are modelled as finite elements using the HGO model in Abaqus (Simulia, USA). All specimens were submitted varus/valgus loading (0-10Nm) while being rigidly fixed on a testing bench to prevent knee flexion. In subsequent computer simulations of the experimental testing, rigid bodies kinematics and the associated soft-tissue force response were computed at each time step. Ligament properties were optimised using a gradient descent approach by minimising the error between the experimental and simulation-based kinematic response to the applied varus/valgus loads. For comparison, a second model was defined wherein collateral ligaments were modelled as nonlinear no-compression spring elements using the Blankevoort formulation.Models with subject-specific, experimentally calibrated HGO representations of the collateral ligaments demonstrated smaller root mean square errors in terms of kinematics (0.7900° +/− 0.4081°) than models integrating a Blankevoort representation (1.4704° +/− 0.8007°).A novel computational workflow integrating subject-specific, experimentally calibrated HGO predicted post-TKA frontal-plane knee joint laxity with clinically applicable accuracy. Generally, errors in terms of tibial rotation were higher and might be further reduced by increasing the interaction nodes between the rigid body model and the finite element software. Future work should investigate the accuracy of resulting models for simulating unseen activities of daily living.

Retractable roof module with photovoltaic panel as small solar power plant

The use of building-integrated photovoltaic (PV) systems in the form of retractable roofs is an alternative option to existing installations without tracking systems (NT) or horizontal single-axis tracking systems (HSAT). This paper presents a retractable roofing module intended for the installation of PV panels. The main objective of this study is to identify modern solutions for these systems in terms of geometry and kinematics, which would allow the displacement of the roof slopes to follow the trajectory of the Sun during the day. This study is based on the parametric modelling and virtual prototyping of engineering objects. A moveable roof module is obtained, which, in addition to its function of shading and protection from rainfall, serves as a small movable solar power plant. The structure of the roof module is based on the construction of a mechanism comprising three revolute kinematic pairs and one prismatic kinematic pair, whose movement is strictly defined. The roof comprised three moving slopes of the same length. One of the slopes is designed for the installation of a PV panel; it moves according to the Sun to obtain maximum energy gains. For an adopted PV panel length of 1.0a, the maximum roof covering space is 2.69a. An analysis of the natural lighting for the panel following the Sun was performed, and the angle of inclination with respect to the horizontal plane was determined. The inclination of the panel ranges from +80º to –75º. In the case analysed, the HSAT delivers approximately 16% more energy than the NT system. The adaptation of retractable roofs with PV panels enables the optimal use of space around buildings, which are occupied by fixed or moveable installations with PV panels.