Pendulum Test Research Articles

Simulation of Bruising in Persimmon Under the Dynamic Impact by the Finite Element Method

ABSTRACTPersimmon is a soft fruit, which is why it is one of the horticultural products most prone to mechanical damage throughout the cold chain. Understanding the impact of this damage on the post‐harvest quality of these fruits is extremely important to reduce losses that occur throughout the supply chain. This study used the finite element method (FEM) to predict the damage to persimmon during impact loading. The tensile and puncture tests were used to find mechanical properties, and the pendulum tests for three levels of impact. During simulation, persimmon was modeled as an elastic–plastic, and the problem was considered a non‐linear explicit procedure. Two different force‐time and initial velocity methods were used for simulation in Abaqus software. Results of the maximum von Mises stress, maximum contact force, deformation, bruise volume, and internal energy indicated that increasing the impact level in both methods resulted in a rise of stress, deformation, bruise volume, and absorbed energy. The average error in contact force in the force‐time and initial velocity methods was 12% and 21%, respectively. Also, the average deformation error in the force‐time and initial velocity methods was 10% and 52%, respectively. According to these results, the force‐time method is more accurate, and the elastic–plastic model can properly represent the behavior of persimmon.

Toward a Test-Based Methodology to Evaluate Unrestrained Torso Neck Braces Using the Hybrid III ATD and MATD Neck

<div>The introduction of unrestrained torso neck braces as a safety intervention for helmeted motorcycle riders has introduced a set of unsolved challenges. Understanding the injury prevention afforded by these devices depends on a reliable test methodology by which to critically evaluate their efficacy against the most common mechanisms of neck injury. An inverted pendulum test is proposed to evaluate compression flexion (CF), tension flexion (TF), and tension extension (TE) of the neck using a Hybrid III anthropomorphic test device (HIII ATD) neck and a motorcycle-specific ATD (MATD) neck. In addition to investigating methods to quantify the beneficial effects of a neck brace, potential adverse effects of such a device are evaluated by measuring and evaluating relevant neck response measures. To that end, measured data using a current neck brace were analyzed and applied to various injury criteria related to the ATD neck used to compare the injury risk predicted by each parameter. The HIII ATD neck allows for a more conservative evaluation due to its exaggerated response in compression and may be more suitable in evaluating the neck injury criterion and injury risk in CF loading for low energy impacts. The MATD neck is limited to certain impact modalities, particularly the uncoupled behavior between head and neck during hyperextension, and individual neck measures at lower impact energy due to its limited structural integrity in direct head impacts. In the proposed tests, injury mechanisms were initially associated with a pre-impact head orientation and expected head and neck motion. However, these associations are not definitive. Although the most relevant neck injury mechanisms related to the unrestrained torso were addressed, the authors suggest that the presented tests are supplemented by a method to evaluate higher energy vertex impacts as a means to determine a neck brace’s efficacy during this loading modality.</div>

Slip Resistance (Friction) and Safe Walk Characteristics of Selected Shoe Soles on Floor Tiles in Nigeria

Slip-related accidents represent a significant public safety concern, particularly in environments where flooring may be exposed to various contaminants. This research investigates the slip resistance characteristics of selected shoe soles on different types of local floor tiles, employing the British Pendulum Tester (BPT) under diverse conditions, including: dry, sandy, wet, soapy, and oily surfaces. The study aims to provide quantitative data on friction coefficients to comprehensively assess the performance of different shoe sole and tile combinations. The results indicate varying levels of slip resistance across the tested combinations, with some shoe soles demonstrating superior performance under specific conditions. For instance, Poly-Urethane soles consistently showed higher friction coefficients in both dry and contaminated conditions, suggesting their suitability for environments prone to slip hazards. Conversely, certain tiles exhibited lower slip resistance when exposed to water and oily substances, highlighting the need for careful selection of both footwear and flooring materials in safety-critical applications. The findings underscore the importance of considering environmental factors in evaluating footwear performance, providing practical implications for improving safety standards in public and private spaces. The data generated from this research can inform recommendations for better footwear design, floor tile selection, and maintenance practices to mitigate slip hazards effectively. This study emphasizes the significance of evidence-based approaches in enhancing slip resistance standards, advocating for ongoing research and industry collaboration to ensure continuous improvement in safety protocols.

Characteristics of Open-Graded Friction Course Macrotexture and Macrostructure and Its Effect on Skid Resistance under Rainfall.

An Open-Graded Friction Course (OGFC) presents a rough surface and a porous structure and provides skid resistance under wet conditions, differing from that of a dense graded mixture. This study explored the distribution of surface macrotexture with depth in OGFC. Using cross-sectional images and semantic image segmentation techniques, the internal structure, porosity, and void size distribution were analyzed to assess the effectiveness of rainfall drainage. Skid resistance was evaluated with a British Pendulum Tester, focusing on the influence of surface macrotexture and internal macrostructure, particularly with regard to contact depth. Results show that finer gradations increase surface roughness peaks, which are concentrated near the top surface. In contrast, coarser mixtures exhibit a greater effective contact depth and more peaks with higher curvature. Finer gradations also result in lower porosity, greater void dispersion, and smaller average void diameters. During heavy rainfall, OGFC-13 exhibits the highest friction coefficient due to its effective contact, surface roughness, and internal voids, which facilitate water expulsion. This research provides insights into the skid resistance mechanism of OGFC in wet conditions and offers practical guidance for selecting the optimal gradation.

A Comparative Study on the Texture of Exposed Aggregate Concrete (EAC) Pavements Using Different Measurement Techniques.

This paper presents issues related to the assessment of the texture of aggregate concrete (EAC) surfaces using various methods for its verification. Microtexture was assessed using the British Pendulum Tester (BPT) and Dynamic Friction Tester (DFT). Two laser profilometers were used to assess macrotexture, circular texture meter (CTM) and stationary laser profilograph (SPL), as well as the commonly known volumetric method. Measurements were carried out on left and right tracks and in between them on five test sections of expressways. Based on the analyses performed, it was found that the results obtained by the DFT were less sensitive to changes in microtexture between individual tracks compared to the results obtained by the BPT. The BPN values in the left track were lower than those in the right track. However, the difference between the DFT20 results in these spots was insignificant. Both MPD and MTD values did not show significant differences between the right and left tracks. However, some differences were observed between the MPD parameters obtained using the CTM and SPL. This resulted from the different frequency and length of the scanned surface profile. However, the differences were at an acceptable level. A very high linear correlation was obtained in the case of BPN and DFT20 values (r - 0.719), and in the case of MPD and MTD values, the correlation was almost certain (r above 0.900). Based on a comparative analysis of the models estimating mean texture depth (MTD/ETD), a significant difference was observed between models based on EAC pavement results and those based on asphalt surfaces.

Evaluating Pavement Skid Resistance: Ensuring Safety and Performance

Skid resistance is a fundamental characteristic of road pavements, directly influencing vehicle control and traffic safety, especially under wet and slippery conditions. Skid resistance is not just about enhancing road surface quality but also about ensuring public safety, economic efficiency, regulatory compliance, and overall user satisfaction within transportation systems. The primary objective of this study is to compare the required and measured skid resistance values of flexible pavement on curved sections of feeder roads originating from Suryabinayak in Bhaktapur district, Nepal. This road is newly developed road with sharp curves which is prone to accidents. This comprehensive study aims with ensuring the safety of drivers and pedestrians by providing necessary recommendations regarding Skid Resistance, Super elevation, Speed of vehicles and Radius of curve. The research encompasses an extensive review of current methodologies for assessing skid resistance, including the British Pendulum Tester. The test results showed that the current pavement design practice of considering skid resistance is unsatisfactory in the case of wet muddy surface.

Acute Whole-Body Vibration Does Not Alter Passive Muscle Stiffness in Physically Active Males

Whole-body vibration (WBV) is a widely used training method to increase muscle strength and power. However, its working mechanisms are still poorly understood, and studies investigating the effects of WBV on muscle stiffness are scant. Therefore, the aim of this study is to investigate the acute effects of WBV on stiffness and countermovement jump (CMJ). Twenty-four recreationally active males, on separate days and in random order, performed a static squat under two different conditions: with WBV (WBV) or without vibration (CC). Muscle stiffness was assessed through the Wartenberg pendulum test, and CMJ was recorded. RM-ANOVA was employed to test differences between conditions in the above-mentioned variables. In the CC condition, stiffness was significantly lower after the exposure to the static squat (p = 0.006), whereas no difference was observed after the exposure to WBV. WBV and CC did not affect CMJ. No significant correlation was observed between changes in CMJ and changes in stiffness. Our results show that WBV may mitigate the reduction in muscle stiffness observed after static squats. However, current results do not support the notion that WBV exposure may account for an increase in CMJ performance.

Improved British pendulum test using curved slider

ABSTRACT The conventional British pendulum tester (BPT) utilises a cuboid rubber slider and measures the skid resistance between its front slider edge and a test surface. This standard test method is known to produce erroneous skid resistance measurements on grooved pavements, owing to impacts between the straight slider edge of BPT and the vertical walls of pavement grooves. To overcome the problem, this study replaced the cuboid slider with a curved slider having an external radius of 100 mm, constructed of the same rubber material as the standard BPT rubber slider. The ability of the proposed improved device to eliminate the vertical-wall impact problem and provide correct skid resistance measurements of a grooved surface was verified experimentally and numerically. A full-scale prototype was fabricated for this purpose. Experimental validation tests involving the standard cuboid-slider BPT and the curved-slider BPT were conducted, and the test results were analysed with the aid of finite-element numerical models. The results confirmed that the proposed curved-slider BPT can provide more consistent and accurate skid resistance measurements compared to the standard BPT, for both grooved and ungrooved pavements.

Comparative assessment of hot and warm mix asphalt to develop a sustainable pavement: Kg Ayer Merah Mersing case study

Abstract In this study, the construction and pavement properties of warm mix asphalt (WMA) in rural areas were examined in comparison with the conventional mixture of hot mix asphalt (HMA). Both WMA and HMA mixtures were constructed at Kg Ayer Merah, Mersing, Johor in accordance with Public Work Department specifications, regarding redesign of road pavements in rural areas. This study to evaluate the comparison performance of WMA and HMA mixtures at one month and four months after construction based on performance in mechanical (Rate of cooling, density, Marshall, resilient modulus and dynamic creep) and macrotexture performance (sand patch and pendulum test value) and environmental analysis (carbon emission). The findings showed that WMA mixtures showed similar and better performance over HMA mixtures after four months construction in mechanical performance. WMA also obtained a higher rate of cooling than HMA besides reducing carbon emissions during production and road construction indicating the mixture more convenient to cater for double handling in rural areas. This huge impact is in line with the sustainable development goals (SDGs), which aim to develop sustainable infrastructure and reduce global warming issues.

Smart Textile Impact Sensor for e-Helmet to Measure Head Injury.

Concussions, a prevalent public health concern in the United States, often result from mild traumatic brain injuries (mTBI), notably in sports such as American football. There is limited exploration of smart-textile-based sensors for measuring the head impacts associated with concussions in sports and recreational activities. In this paper, we describe the development and construction of a smart textile impact sensor (STIS) and validate STIS functionality under high magnitude impacts. This STIS can be inserted into helmet cushioning to determine head impact force. The designed 2 × 2 STIS matrix is composed of a number of material layered structures, with a sensing surface made of semiconducting polymer composite (SPC). The SPC dimension was modified in the design iteration to increase sensor range, responsiveness, and linearity. This was to be applicable in high impact situations. A microcontroller board with a biasing circuit was used to interface the STIS and read the sensor's response. A pendulum test setup was constructed to evaluate various STISs with impact forces. A camera and Tracker software were used to monitor the pendulum swing. The impact forces were calculated by measuring the pendulum bob's velocity and acceleration. The performance of the various STISs was measured in terms of voltage due to impact force, with forces varying from 180 to 722 N. Through data analysis, the threshold impact forces in the linear range were determined. Through an analysis of linear regression, the sensors' sensitivity was assessed. Also, a simplified model was developed to measure the force distribution in the 2 × 2 STIS areas from the measured voltages. The results showed that improving the SPC thickness could obtain improved sensor behavior. However, for impacts that exceeded the threshold, the suggested sensor did not respond by reflecting the actual impact forces, but it gave helpful information about the impact distribution on the sensor regardless of the accurate expected linear response. Results showed that the proposed STIS performs satisfactorily within a range and has the potential to be used in the development of an e-helmet with a large STIS matrix that could cover the whole head within the e-helmet. This work also encourages future research, especially on the structure of the sensor that could withstand impacts which in turn could improve the overall range and performance and would accurately measure the impact in concussion-causing impact ranges.

Numerical modelling of different airbag folding patterns and their influence on occupant responses in frontal vehicle impact

This paper presented a procedure for airbag folding for the application in occupant safety studies and analysed the influence of different airbag folding patterns on the occupant severity in frontal impact. Airbags were folded in two patterns: zig-zag and top-roll, using two folding techniques: Initial Metric Method and Explicit Folding. The explicit folding was found to be more expensive in terms of preparation time. However, this approach provided more control over the whole folding process. The Initial Metric Method was more robust, however, it’s hard to apply for complex folding patterns. Deployments of airbags were validated against experimental data of pendulum tests. Those airbag models were applied to 2006 Ford F250 pickup truck. This vehicle was used for simulations of frontal vehicle impact where the 50th male Hybrid III crash test dummy was an occupant. Results of this simulation were compared with an actual test with a similar vehicle, under the same impact conditions. Results showed the head and chest accelerations were lower for top-roll folded airbag cases, however neck normal forces were higher compared to zig-zag folded airbag. The internal pressure in the early stage of deployment was 33% higher for the top-roll folded airbags.

Design Optimization of LCV CAB for Frontal Pendulum Test: Enhancing Survival Space Improvement Through Frugal Load Path Transfer Techniques

In the fiercely competitive landscape of the automotive industry, Original Equipment Manufacturers (OEMs) encounter substantial challenges in the realm of Research and Development (R&D), particularly in the pursuit of lightweight design without compromising safety. As a result, the automotive sector continuously seeks innovative tools and methodologies to substantially optimize the structural composition of Light Commercial Vehicle (LCV) segments. The design of lightweight cabins, while simultaneously ensuring crashworthiness, not only plays a pivotal role in determining the market success of a new LCV but also holds significant legal implications. One well-established and indispensable evaluation tool to ascertain compliance with critical homologation requirements is the frontal pendulum test. This test serves as a litmus test for the appropriate design of Body in White (BIW) architecture, crucial for safeguarding occupant safety in unforeseen emergency scenarios.Within the context of adhering to styling themes and the design intent governing the three-dimensional (3D) geometry, a notable deviation emerged in the form of a 33 mm extension of the front panel in the newly stylized cabin. This deviation presented CAB engineers with a formidable challenge, as it disrupted the conventional load path of the frontal pendulum, rerouting it to the CAB itself instead of the intended transfer to the frame via the bull bar. The primary objective of this work is to restore the load path to the frame, all the while adhering to the original styling intent and refraining from introducing any additional modifications to major adjacent components such as the bumper and bumper reinforcement. Furthermore, this undertaking extends to encompass an exploration of cost reduction opportunities within the ambit of the newly styled CAB.
 Keywords: LCV CAB, Frontal Pendulum, Frugal Load, Occupant safety regulation, Styling impact, Pendulum impact, CAE simulation

A portable system to measure knee extensor spasticity after spinal cord injury

BackgroundThe pendulum test is a quantitative method used to assess knee extensor spasticity in humans with spinal cord injury (SCI). Yet, the clinical implementation of this method remains limited. The goal of our study was to develop an objective and portable system to assess knee extensor spasticity during the pendulum test using inertial measurement units (IMU).MethodsSpasticity was quantified by measuring the first swing angle (FSA) using a 3-dimensional optical tracking system (with external markers over the iliotibial band, lateral knee epicondyle, and lateral malleolus) and two wireless IMUs (positioned over the iliotibial band and mid-part of the lower leg) as well as a clinical exam (Modified Ashworth Scale, MAS).ResultsMeasurements were taken on separate days to assess test–retest reliability and device agreement in humans with and without SCI. We found no differences between FSA values obtained with the optical tracking system and the IMU-based system in control subjects and individuals with SCI. FSA values from the IMU-based system showed excellent agreement with the optical tracking system in individuals with SCI (ICC > 0.98) and good agreement in controls (ICC > 0.82), excellent test–retest reliability across days in SCI (ICC = 0.93) and good in controls (ICC = 0.87). Notably, FSA values measured by both systems showed a strong association with MAS scores (ρ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\uprho$$\\end{document} ~ −0.8) being decreased in individuals with SCI with higher MAS scores, reflecting the presence of spasticity.ConclusionsThese findings suggest that our new portable IMU-based system provides a robust and flexible alternative to a camera-based optical tracking system to quantify knee extensor spasticity following SCI.

Skin and not dorsal root stimulation reduces hypertonus in thoracic motor complete spinal cord injury: a single case report.

On demand and localized treatment for excessive muscle tone after spinal cord injury (SCI) is currently not available. Here, we examine the reduction in leg hypertonus in a person with mid-thoracic, motor complete SCI using a commercial transcutaneous electrical stimulator (TES) applied at 50 or 150 Hz to the lower back and the possible mechanisms producing this bilateral reduction in leg tone. Hypertonus of knee extensors without and during TES, with both cathode (T11-L2) and anode (L3-L5) placed over the spinal column (midline, MID) or 10 cm to the left of midline (lateral, LAT) to only active underlying skin and muscle afferents, was simultaneously measured in both legs with the pendulum test. Spinal reflexes mediated by proprioceptive (H-reflex) and cutaneomuscular reflex (CMR) afferents were examined in the right leg opposite to the applied LAT TES. Hypertonus disappeared in both legs but only during thoracolumbar TES, and even during LAT TES. The marked reduction in tone was reflected in the greater distance both lower legs first dropped to after being released from a fully extended position, increasing by 172.8% and 94.2% during MID and LAT TES, respectively, compared with without TES. Both MID and LAT (left) TES increased H-reflexes but decreased the first burst, and lengthened the onset of subsequent bursts, in the cutaneomuscular reflex of the right leg. Thoracolumbar TES is a promising method to decrease leg hypertonus in chronic, motor complete SCI without activating spinal cord structures and may work by facilitating proprioceptive inputs that activate excitatory interneurons with bilateral projections that in turn recruit recurrent inhibitory neurons.NEW & NOTEWORTHY We present proof of concept that surface stimulation of the lower back can reduce severe leg hypertonus in a participant with motor complete, thoracic spinal cord injury (SCI) but only during the applied stimulation. We propose that activation of skin and muscle afferents from thoracolumbar transcutaneous electrical stimulation (TES) may recruit excitatory spinal interneurons with bilateral projections that in turn recruit recurrent inhibitory networks to provide on demand suppression of ongoing involuntary motoneuron activity.

Evaluation of the Effect of De-icing Chemicals on Performance of Airport Concrete Pavement under Freeze-Thaw Cycles

Weather conditions such as rainfall and freeze-thaw cycles affect the pavement performance of airports; therefore, methods such as using de-icing chemicals are considered in order to maintain the normal condition of the airport runway. In addition to the above factors, de-icing chemicals play an important role in pavement performance and the damage caused to it due to their chemical nature. Therefore, investigating the effect of de-icing chemicals and determining the appropriate material to maintain the airport's pavement is a priority for engineers. In this study, the effect of three de-icing chemicals, sodium chloride, potassium acetate, and ethylene glycol (at concentrations of 23.3%, 49%, and 69.07%, respectively) on skid resistance (The British Pendulum Test (BPT) and The Road Test Machine (RTM)) and the mechanical properties (Compressive Strength Test) of the concrete under Freezing and Thawing Cycle were investigated. The BPT test results showed that sodium chloride resulted in better skid resistance than other chemicals when the number of cycles is more than 100 cycles. This result was also obtained for all cycles in the RTM test. Also, ethylene glycol was not suitable for improving skid resistance based on BPT and RTM tests. Furthermore, the results of the compressive strength of concrete mixtures showed that the de-icing chemicals reduced the compressive strength of concrete mixtures. Based on all the results, sodium chloride had better results than other chemicals.

Vacuum pendulum test for a modified Kaluza–Klein theory

Experiments were performed in vacuum to examine a modified Kaluza–Klein theory. Originally proposed by Mbelek and Lachièze-Rey, the 5D Kaluza–Klein-[Formula: see text] theory includes an external scalar field [Formula: see text] to couple gravitational and electromagnetic fields and can be used to explain some misunderstood phenomena in physics. The theory predicts that a pendulum will experience detectable forces exceeding predictions from classical electromagnetism when interacting with a scalar field. In this experiment, a dielectric mirror is hung as a pendulum inside a vacuum chamber and its oscillations are examined with two laser interferometers. In proximity to the pendulum, different solenoids and toroids will induce magnetic fields that can also be shielded to a great extent using a Gauss chamber. The experiments were conducted in a vacuum chamber to allow the measurement of torsion angles as low as 0.1[Formula: see text]arcsec above the noise, as well as 0.1[Formula: see text][Formula: see text]m translations of the pendulum. The phenomenon observed differs from what was observed by Mbelek at ambient pressure in both magnitude and behavior. Dummy test results hint at the presence of convection effects to explain the pendulum’s rotation, which was eliminated under higher vacuum and by placing a wall between the solenoid and pendulum. In the presence of stronger magnetic fields, the pendulum’s translation was observed to agree with effects predicted by a consideration of diamagnetic effects.

Characteristics of novel cycloaliphatic epoxides based on UV-induced cationic ring-opening polymerization for plastic coatings

Cationic ring-opening polymerization (CROP)-capable cycloaliphatic epoxide monomers bearing a benzyl ether group (CE-BEs) were developed as glass-replacement plastic coatings for lightweight automobiles. Three different monomers of bis(((7-oxabicyclo[4,1,0]heptan-3-yl)methoxy)methyl)benzene isomers were synthesized to provide the cycloaliphatic epoxide functional groups. 1H and 13C nuclear magnetic resonance and Fourier transform infrared (FT-IR) spectroscopic analyses confirmed that the monomers were successfully synthesized. The shear viscosity and real-time crosslinking behavior of the CROP coatings were investigated using a rheometer. In particular, the release of thermal energy via CROP under UV irradiation was monitored using differential scanning photocalorimetry. The reaction conversion of cycloaliphatic epoxides by CROP before and after UV irradiation was verified using FT-IR spectroscopy. The transparency of the CROP coating films cured on a polycarbonate substrate was measured using an ultraviolet–visible spectrophotometer, and their adhesion was confirmed using cross-cut tests. For characterization of the surface mechanical properties, a nanoindentation tester and a nanoscratch tester were used in conjunction with an atomic force microscope to evaluate the surface hardness and scratch resistance, respectively. In addition, the thermomechanical properties of the cured CROP coating films were investigated using a rigid-body pendulum tester operated in dynamic physical mode. The ternary coating systems with CE-BEs were found to exhibit high photoreactivity, a dense crosslinking density, a transparent appearance, and enhanced adhesion and mechanical properties, making it suitable for glass-replacement plastic coatings.

The effect of body position, leg dominance, and automatic releasing mechanism on quadriceps muscle tone assessed by Pendulum Test in able-bodied persons.

<p>Quadriceps femoris muscle spasticity is commonly measured by the Wartenberg pendulum test. It is generally assumed that lower values of the number of swings of the leg and lower relaxation indexes are associated with higher muscle tone and more spasticity. Still, there is incoherence regarding the test&rsquo;s applications with various body positions and starting mechanisms. This study aims to investigate the influence of body position, leg dominance, and automatic leg-releasing mechanism on muscle tone measured by pendulum test in healthy population whose muscle tone is often compared to the spastic muscle tone of patients with neurologic disorders.&nbsp;</p>. <p>15 healthy adults (age: 19-32 years, 9 males, 6 females) participated in this study. A Zebris 3D ultrasound-based motion analysis system was used to record kinematic data during the pendulum test. The number of swings of the leg and the relaxation index were computed from the collected data. The pendulum test was completed in eight conditions: in supine and semi-supine positions on the dominant and non-dominant leg separately and with investigator-release and automata-release mechanisms. Paired t-tests and Wilcoxon test with the significance level of .05 were applied in comparison of pairs of the pendulum test condition.</p>. <p>1) Applying automata-release mode, in the non-dominant leg the number of swings (p=0.03) and the relaxation index (p&lt;0.001) were significantly higher in semi-supine than in supine position. 2) The non-dominant leg had significantly more swings than the dominant leg in both body positions with automata-release mode (p=0.009, p&lt;0.001). In investigator-release mode this occurred in supine position (p&lt;0.001). 3). Regarding the number of swings in investigator-release versus automata-release mode, no significant differences were found in any test condition, but the relaxation index showed significant difference for the non-dominant leg (p=0.01, p=0.009). 4) The values of the relaxation index didn&rsquo;t support in all test conditions the results what the number of swings provided about the muscle tone. In automata-release mode, the dominant leg has a lower number of swings and a higher relaxation index than the non-dominant leg.</p>. <p>The effect of body position on the quadriceps muscle tone can be assessed by applying the pendulum test with an automatic leg-releasing mechanism even when the application of conventional investigator-release mode does not show a significant effect. The pendulum test is more sensitive to assess spasticity with automatic-release than with investigator-release mode.&nbsp;</p>.

Identification of Neural and Non-Neural Origins of Joint Hyper-Resistance Based on a Novel Neuromechanical Model.

Joint hyper-resistance is a common symptom in neurological disorders. It has both neural and non-neural origins, but it has been challenging to distinguish different origins based on clinical tests alone. Combining instrumented tests with parameter identification based on a neuromechanical model may allow us to dissociate the different origins of joint hyper-resistance in individual patients. However, this requires that the model captures the underlying mechanisms. Here, we propose a neuromechanical model that, in contrast to previously proposed models, accounts for muscle short-range stiffness (SRS) and its interaction with muscle tone and reflex activity. We collected knee angle trajectories during the pendulum test in 15 children with cerebral palsy (CP) and 5 typically developing children. We did the test in two conditions - hold and pre-movement - that have been shown to alter knee movement. We modeled the lower leg as an inverted pendulum actuated by two antagonistic Hill-type muscles extended with SRS. Reflex activity was modeled as delayed, linear feedback from muscle force. We estimated neural and non-neural parameters by optimizing the fit between simulated and measured knee angle trajectories during the hold condition. The model could fit a wide range of knee angle trajectories in the hold condition. The model with personalized parameters predicted the effect of pre-movement demonstrating that the model captured the underlying mechanism and subject-specific deficits. Our model may help with the identification of neural and non-neural origins of joint hyper-resistance and thereby opens perspectives for improved diagnosis and treatment selection in children with spastic CP, but such applications require further studies to establish the method's reliability.

Preliminary assessment of the properties of composite layers based on porous asphalt and coloured mortar

The paper presents the results of the properties of composite layers made of porous asphalt, with a void content above 30%, filled with a special-coloured mortar. Three mortars of white, red and blue colours were selected, whose compressive strength after 2 days was over 60 MPa and the flexural strength was over 7 MPa. The study of composite layer aimed at determination of the water sensitivity expressed in ITSR (Indirect Tensile Strength Ratio) according to the standard EN 12697-12 (method A) and rutting resistance according to standard EN 12697-22 in the small apparatus (method B). The results indicate that such solutions will be justified in places with extremely heavy traffic, such as bus stops. In addition, the condition of the layer surface after simulating its wear was assessed using of the CTM (Circular Track Meter), the BPT (British Pendulum Tester) and a reflectometer. The results indicate that they can be used in areas with low speed limits. On the other hand, the possibility of introducing the pigment into the mortar has a positive effect on surface of those elements of the communication system, which should have a different color than the road surface. These are the surfaces of bicycle paths, pedestrian and bicycle routes, areas of intersections, where their visibility plays an important role due to the safety of users.