Usual Speed Research Articles

Pet Attachment and Maintenance of Physical and Cognitive Function in Community-Residing Older Adults: Evidence From the Baltimore Longitudinal Study of Aging (BLSA)

ABSTRACT Pet ownership is associated with reduced deterioration in physical and cognitive function as older adults age. To date, little research focuses on whether the degree of attachment to the pet is related to the rate of deterioration in these functions. We examined the relationship of pet, dog, and cat attachment to changes in physical and cognitive function among 214 pet-owning, generally healthy, community-dwelling adults aged 50–100 years (M = 68.0, SD = 7.8) from the Baltimore Longitudinal Study of Aging (BLSA). Pet attachment was assessed using the pet ownership module administered during a regularly scheduled BLSA visit. Physical and cognitive assessments were administered every 1–4 years over 1–13 years (M = 7.5, SD = 3.6), including 400-meter walk time, usual and rapid-gait speed, Health ABC Physical Performance Battery, SF-12 Physical Component Score, California Verbal Learning (Immediate, Short, Long recall), Benton Visual Retention, Trail-Making (Trails A, B, B-A), Digit Span, Boston Naming (Naming), and Digit Symbol Substitution (Digit Symbol) Tests. In linear mixed models, controlling for age and comorbidities, greater pet attachment was associated with slower deterioration in physical performance (p = 0.009), usual-gait speed (p < 0.001), rapid-gait speed (p = 0.002), and executive function (Trails B: p = 0.005 and Trails B-A: p < 0.001), and faster deterioration in long-term recall (p < 0.001). Among dog owners (n = 121), a higher attachment was associated with slower deterioration in attention (Trails A: p = 0.046) and faster deterioration in short- (p = 0.025) and long-term (p = 0.019) recall. Among cat owners (n = 100), higher attachment was associated with a slower decline in physical wellbeing (p = 0.035). We provide important longitudinal evidence that pet attachment is differentially associated with the rate of decline in function older adults experience as they age and that attachment to different types of pets may have a different relationship to rates of decline. Potential explanations for these differences are proposed.

Impact of Xsens Technology on Analysis of Gait Deviation in Pre- and Post-surgical Total Knee Arthroplasty Patient.

Introduction Osteoarthritis (OA) is a degenerative joint ailment that predominantly affects the knee and is most common in older adults. It destroys the surrounding tissues and cartilage. Following total knee arthroplasty (TKA), patients with end-stage knee OA can have long-term pain reduction and patient satisfaction, although certain functional limitations still exist. While TKA significantly reduces pain and improve function, many patients stillexperience abnormalities post-surgery, such as slower walking and reduced step-length. Gait analysis using technologies like the Xsens Motion Visualization and Navigation (MVN) system (Movella, Henderson, NV, USA)provides insights into these functional limitations, helping to assess knee mobility and predict changes in joint movements during activities. Methods Thirty-four people participated in a study done at the Centre for Advance Physiotherapy Education and Research, Ravi Nair Physiotherapy College, Wardha, both before and after total knee arthroplasty. Participants who ranged in age from 50 to 70 and had undergone unilateral TKA were included. Informed consent was obtained, and demographic data were collected. Participants walked a predetermined distance at their usual speed, and measurements of hip and knee angular velocity and center of mass were recorded for gait analysis. Result The study involved participants aged 50-70, with a mean age of 59.79 years and height ranging from 153.00 to 185.00 cm. Significant gait changes were noted pre- and post-total knee arthroplasty, including a decrease in walking speed from 0.72 to 0.55m/s and cadence from 105.06 to 82.86. Other parameters, such as step length and center of mass, also exhibited considerable differences, highlighting the impact of TKA on gait dynamics. Conclusion The study underscores the significant impact of total knee arthroplasty on gait mechanics and the value of advance of technologies likeXsens for assessing functional outcomes. While TKA provides pain relief and improved mobility, residual gait abnormalities persist, highlighting the need for tailored rehabilitation. Xsens technology enhances patient preparation, recovery tracking, and rehabilitation strategies, setting a new standard for gait analysis in orthopedic practice.

Londrina Activities of Daily Living Protocol: validity, reliability, minimal detectable change, and standard error of measurement in adults with asthma

Introduction Asthma symptoms are dyspnea, chronic cough, wheezing, chest tightness, or chest discomfort, which can directly limit the activities of daily living (ADL), which is frequently reported by adults with asthma. Evaluating ADL with a reliable protocol at the usual speed is necessary. Objectives To investigate the validity, reliability, minimal detectable change (MDC), and standard error of measurement (SEM) of the Londrina ADL Protocol (LAP) for adults with asthma. Methods Adults with asthma were evaluated with the LAP test. Spearman’s correlation coefficient was used to verify validity with the 6-min walk test (6MWT), Glittre-ADL test, and London Chest Activity of Daily Living (LCADL). To test the reliability, the test was reapplied in at least 30 min; the Wilcoxon test and Intraclass Correlation Coefficient (ICC), SEM, MDC, and learning effect were performed. Results Fifty-three individuals were included (26% men, 43 ± 15 years, BMI 28 ± 8 kg/m2, FEV1 70 ± 24%predicted). For convergent validity, the LAP test was correlated with the 6MWT, Glittre-ADL, and LCADL scale (r = −0.49, 0.71, and 0.30, respectively; p < 0.03). There was a difference in test-retest (p < 0.0001) and reliability analysis shows ICC3 of 0.94, SEM of 14.88 s (22%), and MDC of 41.23 s (15%). Furthermore, the individuals performed the second test with −23 ± 19 (7.9%) s. Conclusion The LAP test is valid and reliable for assessing limitations during ADL in adults with asthma. Considerable learning effect was observed, therefore, the best of two measures may avoid underestimation.

Improving the neuromuscular fitness of patients with type 2 diabetes by aquatic exercise training - The Diabetes and Aquatic Training Study (DATS 3): a randomized controlled trial.

To compare the effects of aquatic aerobic and combined training on neuromuscular outcomes in patients with type 2 diabetes. Patients with type 2 diabetes were randomized to an aerobic aquatic training (AERO), a combined aquatic training (COMBI) or a procedure control (CON) three weekly for 15 weeks. The sessions were 50 minutes long. Maximal strength and muscle endurance were assessed by the 1RM and maximum repetitions at 60% 1RM tests, respectively, in knee extension and elbow flexion exercises. Timed up and go test, testosterone, cortisol and testosterone:cortisol ratio also were evaluated. Participants had 59.0±8.2 years, 51% women. All groups increased (P<0.001) the maximal knee extension strength (Mean Difference: AERO: 21.1 kg; COMBI: 14.6 kg; CON: 4.4 kg), while only COMBI group increased (P<0.001) the maximal elbow flexion strength (Mean Difference: 2.6 kg). Muscle endurance in both exercises were increased in all groups. The Timed Up and Go test at the usual and maximal speed decreased in all groups. Testosterone were not modified in present study, while cortisol and testosterone:cortisol were improved in COMBI group. Aquatic training, especially combined aquatic training, improve the neuromuscular fitness of patients with type 2 diabetes.

Normative values and reference equations of the 4-meter gait speed test for Portuguese adults: a cross-sectional study

Purpose To determine the normative values and reference equations of the 4-Meter Gait Speed Test (4MGS) at usual and maximal speed for Portuguese adults. We also assessed the participant experience during the performance of the 4MGS. Materials and methods A cross-sectional study was conducted with individuals without disabilities. Sociodemographic, anthropometric, smoking habits and physical activity (Brief Physical Activity Assessment Tool [BPAAT]) data were collected. Individuals performed 3 repetitions of 4MGS at usual and maximal speeds, and the best performances were recorded. Speed values were calculated by age and sex. Stepwise multiple regressions were used for the reference equations. Participants rated their comfort from 0 (‘not comfortable at all’) to 5 (‘very comfortable’) for each modality and indicated their preferences. Results A total of 287 individuals (62.4% female; 47.8 ± 19.5 years) were recruited. Speed was significantly reduced after the sixth decade of life compared with the other decades (p < 0.001). Reference equations were: Usual speed = 1.598 – (0.006 x age) + (0.060 x BPAAT classification), R2= 27% and Maximal speed = 2.272 – (0.010 x age) + (0.157 x sex) + (0.73 x BPAAT classification), R2= 38%. Most participants felt ‘very comfortable’ performing the 4MGS at usual speed (94.8%), maximal speed (75.6%) and no preference in 4MGS modalities (69%). Conclusions Speed is significantly affected by age. For the reference equations, age and physical activity explain the results of usual speed, and both associated with sex explain the results of maximal speed. Most participants were highly comfortable and expressed no preference in 4MGS modalities.

Functional lower extremity strength influences stepping strategy in community-dwelling older adults during single and dual-task walking

As age increases, a decline in lower extremity strength leads to reduced mobility and increased fall risks. This decline outpaces the age-related reduction in muscle mass, resulting in mobility limitations. Older adults with varying degrees of mobility-disability use different stepping strategies. However, the link between functional lower extremity strength and stepping strategy is unknown. Therefore, understanding how age-related reductions in functional lower extremity strength influence stepping strategy is vital to unraveling mobility limitations. Twenty participants (17F, 72 ± 6 years) were recruited and tested at a local community event. Participants were outfitted with inertial measurement units (IMU) and walked across a pressurized walkway under single and dual motor task conditions (walking with and without carrying a tray with water) at their usual and fast speeds. Participants were dichotomized into normal (11) or low functional strength groups (9) based on age-specific normative cutoffs using the instrumented 5-repetition Sit-to-Stand test duration. Our study reveals that older adults with normal strength prefer adjusting their step time during walking tasks, while those with reduced strength do not exhibit a preferred stepping strategy. This study provides valuable insights into the influence of functional lower extremity strength on stepping strategy in community-dwelling older adults during simple and complex walking tasks. These findings could aid in diagnosing gait deviations and developing appropriate treatment or management plans for mobility disability in older adults.

Novel Plasmonic Metamaterials Based on Metal Nano-Hemispheres and Metal-Dielectric Composites

We introduce a groundbreaking plasmonic metamaterial, the Nano-Hemisphere on Hyperbolic Metamaterial (NHoHMM), which involves the fabrication of Ag nano-hemispheres on a multilayered Ag/SiO2 structure, achieved solely through sputtering and heat treatment. Finite Difference Time Domain (FDTD) simulations unveil the intriguing slow propagation of the localized electric field, where light travels at only 1/40th of its usual speed within this structure. These simulations reveal distinctive sharp absorption peaks in the visible spectrum, attributed to surface plasmon resonance. In practical experiments, the NHoHMM structure, characterized by random Ag nano-hemispheres, exhibits broad absorption peaks spanning the visible range, rendering it a versatile broadband optical absorber. For comparison, the optical properties of the Ag nano-hemispheres on a nanocermet (NHoNC) structure were analyzed through simultaneous sputtering of Ag and SiO2 followed by heat treatment. Simulations employing effective medium theory and the transfer matrix method demonstrate variable optical properties dependent on the Ag filling ratio in the nanocermet structure. The results obtained differ from the spectra of the NHoHMM structure; thus, it is concluded that in the NHoHMM structure, the calculated multi-peaks are broadened due to the inhomogeneity of the nano-hemispherical structure’s size, rather than the metal/dielectric multilayer structure being altered by the heat treatment.

Propulsive forces and muscle activation during gait: comparisons between premenopausal and postmenopausal midlife women.

The aim of this study was to investigate whether there is a reduction in propulsive force during gait in postmenopausal women compared with premenopausal women. Forty-four women (21 premenopausal and 23 postmenopausal women) aged 40 to 55 years were selected. The ability to reach peak propulsive forces was assessed during the step execution test. The test was performed at the usual speed on 2 nonconsecutive days, with two attempts per day, using a force platform. Four temporal parameters were defined and calculated: initiation phase, preparation phase, swing phase, and total time. Peak force (anteroposterior and vertical) and time to reach peak force were obtained in both preparation and swing phases. The rate of force development was defined as peak force divided by time to reach peak force. The postmenopausal women group presented a longer time in the preparation phase (540.6 ± 77 ms vs 482.5 ± 93 ms, P = 0.024) and consequently a longer total time in the step execution test (1,191 ± 106.4 ms vs 1,129 ± 114.3 ms, P = 0.045). There were differences between the groups for the rate of force development in the anteroposterior (postmenopausal women, 142.5 ± 38.1 N/s vs premenopausal women, 174.7 ± 70.5 N/s; P = 0.022) and vertical directions in the preparation phase (postmenopausal women, 102.7 ± 62.3 N/s vs premenopausal women, 145.3 ± 71 N/s; P = 0.012). No significant differences ( P > 0.05) were found in force, time to peak force, and rate of force development during the swing phase. In addition, there were no observed differences in surface electromyography of the medial and lateral gastrocnemius muscles during the preparation phase and swing phase of the step execution test between the two groups. Postmenopausal women exhibited lower ability to generate propulsive force rapidly (rates of force development) in both the anteroposterior and vertical directions during the preparation phase of gait compared with premenopausal women. This indicates that postmenopausal women experience a reduction in propulsive force during gait.

Application of Dynamic Mode Decomposition to Characterize Temporal Evolution of Plantar Pressures from Walkway Sensor Data in Women with Cancer.

Pressure sensor-impregnated walkways transform a person's footfalls into spatiotemporal signals that may be sufficiently complex to inform emerging artificial intelligence (AI) applications in healthcare. Key consistencies within these plantar signals show potential to uniquely identify a person, and to distinguish groups with and without neuromotor pathology. Evidence shows that plantar pressure distributions are altered in aging and diabetic peripheral neuropathy, but less is known about pressure dynamics in chemotherapy-induced peripheral neuropathy (CIPN), a condition leading to falls in cancer survivors. Studying pressure dynamics longitudinally as people develop CIPN will require a composite model that can accurately characterize a survivor's gait consistencies before chemotherapy, even in the presence of normal step-to-step variation. In this paper, we present a state-of-the-art data-driven learning technique to identify consistencies in an individual's plantar pressure dynamics. We apply this technique to a database of steps taken by each of 16 women before they begin a new course of neurotoxic chemotherapy for breast or gynecologic cancer. After extracting gait features by decomposing spatiotemporal plantar pressure data into low-rank dynamic modes characterized by three features: frequency, a decay rate, and an initial condition, we employ a machine-learning model to identify consistencies in each survivor's walking pattern using the centroids for each feature. In this sample, our approach is at least 86% accurate for identifying the correct individual using their pressure dynamics, whether using the right or left foot, or data from trials walked at usual or fast speeds. In future work, we suggest that persistent deviation from a survivor's pre-chemotherapy step consistencies could be used to automate the identification of peripheral neuropathy and other chemotherapy side effects that impact mobility.

User perception of a developed GCash cash-in and cash-out machine in the Philippines

&lt;span&gt;The use of cashless credits in the Philippines has grown since the pandemic has begun. However, the transitions to these changes using cashless transactions have to be addressed. Kiosks and other machines that offer cash-in have been significant, but a model that does not use transactions through banks can be possible which can offer both cash-in and cash-out transactions. In this paper, a developed machine that caters both GCash cash-in and cash-out has been evaluated based on users’ perception on functionality, acceptability, and usefulness. The machine is built with a graphical user interface (GUI) which is a programmed touch screen monitor, bill acceptor, and bills and coins dispenser. The functionality based on the 50 users’ perceptions resulted in 94% excellent in loading bills, 92% accuracy on receiving the cash-in amount less the charges, 92% in dispensing bills less the charges, and 72% faster than the usual speed of transaction. All the respondents agreed that the machine is very convenient and user-friendly, while 94% said that it is very useful and they wanted it in their area. The results suggest that the machine be deployed for public use and be reproduced.&lt;/span&gt;

Novel Genetic and Phenotypic Expansion in GOSR2-Related Progressive Myoclonus Epilepsy.

Biallelic variants in the Golgi SNAP receptor complex member 2 gene (GOSR2) have been reported in progressive myoclonus epilepsy with neurodegeneration. Typical clinical features include ataxia and areflexia during early childhood, followed by seizures, scoliosis, dysarthria, and myoclonus. Here, we report two novel patients from unrelated families with a GOSR2-related disorder and novel genetic and clinical findings. The first patient, a male compound heterozygous for the GOSR2 splice site variant c.336+1G>A and the novel c.364G>A,p.Glu122Lys missense variant showed global developmental delay and seizures at the age of 2 years, followed by myoclonus at the age of 8 years with partial response to clonazepam. The second patient, a female homozygous for the GOSR2 founder variant p.Gly144Trp, showed only mild fine motor developmental delay and generalized tonic-clonic seizures triggered by infections during adolescence, with seizure remission on levetiracetam. The associated movement disorder progressed atypically slowly during adolescence compared to its usual speed, from initial intention tremor and myoclonus to ataxia, hyporeflexia, dysmetria, and dystonia. These findings expand the genotype-phenotype spectrum of GOSR2-related disorders and suggest that GOSR2 should be included in the consideration of monogenetic causes of dystonia, global developmental delay, and seizures.

Torque ripples enhancement of a PMBLDC motor propelled through quadratic DC–DC boost converter at varying load

The characteristic effects of a permanent magnet brushless dc (PMBLDC) motor which is propelled by a quadratic DC–DC boost converter was investigated in this paper. The boost converter applied inductor coupling with semi-conductor switches which operate concurrently to produce a high conversion voltage ratio. Modeling of the PMBLDC motor was presented while simulation was performed using a closed loop control system with different controllers for the enhancement of torque–speed performance at varied load. Simulation results show that an optimum voltage gain with minimum voltage stress was achieved at 0.9 duty cycle while varying the inductor turns ratio (n) from 1 to 6 and inductor coupling coefficient (K) from 0.1 to 1.0 so as to ensure that the entire flux generated in one coil is fully linked to the other. A simplified PI controller was designed and experimented through simulation for excellent drive performance at varying load. The results from the spectral display show that the usual speed oscillation and torque ripples produced by the machine were attenuated using different speed controllers. The Total Harmonic Distortion (THD) values indicate that the PID controller achieved a minimal value of 24.06% for speed and 23.16% for torque as compared to 28.73% and 29.82% obtained from the PI controller, while the P controller achieved 41.88% and 35.67% as shown in the graphical abstract.

Improved Performance for PMSM Sensorless Control Based on Robust-Type Controller, ESO-Type Observer, Multiple Neural Networks, and RL-TD3 Agent.

This paper summarizes a robust controller based on the fact that, in the operation of a permanent magnet synchronous motor (PMSM), a number of disturbance factors naturally occur, among which both changes in internal parameters (e.g., stator resistance Rs and combined inertia of rotor and load J) and changes in load torque TL can be mentioned. In this way, the performance of the control system can be maintained over a relatively wide range of variation in the types of parameters mentioned above. It also presents the synthesis of robust control, the implementation in MATLAB/Simulink, and an improved version using a reinforcement learning twin-delayed deep deterministic policy gradient (RL-TD3) agent, working in tandem with the robust controller to achieve superior performance of the PMSM sensored control system. The comparison of the proposed control systems, in the case of sensored control versus the classical field oriented control (FOC) structure, based on classical PI-type controllers, is made both in terms of the usual response time and error speed ripple, but also in terms of the fractal dimension (DF) of the rotor speed signal, by verifying the hypothesis that the use of a more efficient control system results in a higher DF of the controlled variable. Starting from a basic structure of an ESO-type observer which, by its structure, allows the estimation of both the PMSM rotor speed and a term incorporating the disturbances on the system (from which, in this case, an estimate of the PMSM load torque can be extracted), four variants of observers are proposed, obtained by combining the use of a multiple neural network (NN) load torque observer and an RL-TD3 agent. The numerical simulations performed in MATLAB/Simulink validate the superior performance obtained by using properly trained RL-TD3 agents, both in the case of sensored and sensorless control.

Changes in the normal baseline due to changes in the Coast's dynamics and Their effects on the sea boundary in Weh Island, Nanggroe Aceh Darussalam, Indonesia

The United Nations Convention on the Law of the Sea (UNCLOS) 1982 gave archipelagic states the authority to set maritime boundaries based on such baselines. The basepoint is any point on the usual normal baseline. The base point must be established where the beach's sea level and lowest tide coincide. The location of the base point will change if the coastline's terrain or sea level changes due to physical land- and water-based causes. The reference to establish marine limits will change if the base point changes.It is possible to discover deviations from the average baseline by combining multitemporal satellite imagery with remote sensing techniques. Using satellite images, the position of the shoreline is established according to the time of image acquisition. Utilizing tidal analysis data on changes in vertical position and the slope of the coastal topography, the position of the immediate coastline is then restored to the low water line/normal baseline. Using normal baseline data, the Digital Shoreline Analysis System (DSAS) method is utilized to calculate the rate and rate of temporal changes.According to calculations of the usual baseline's speed and acceleration on the eastern portion of Weh Island, which has a Base Point (TD) of 178, the baseline has drifted 21 m seaward between 2017 and 2022, growing on average approximately 5 m per year. Consequently, coastal dynamics must be taken into account when calculating the base point if the location of TD 178 is updated in accordance with UNCLOS 1982 standards.

Investing Data Flow Issue by using Rayleigh Model in Cloud Computing

Programming groups benefit significantly from programming error forecasting, which also advances current achievement. Programming imperfection expectation has been the subject of experimental studies on both inside- and outside-project deformity forecast. However, current analyses dont appear to be able to provide a method for estimating the number of flaws in a soon-to-be-released product. This paper describes such an approach and determines the relationship between each indicator variable and the total number of defects using indicator variables obtained from the deformity speed increase, namely the imperfection thickness, deformity speed, and imperfection presentation time. We describe how a coordinated AI strategy was used in light of relapse models created using these indicator criteria. 3 distinct datasets with 228 occurrences were taken from the Kaggle store and subjected to analysis. The modified R-square for the relapse model developed as a component of the usual deformity speed was 98.6%, with a p-value of 0.001 being achieved. With a connection value of 0.98, the average deformity speed is clearly correlated with the number of flaws. As a result, it is demonstrated how this process might provide a framework for programmer testing in order to increase the viability of programming advancement activities.

SPATIOTEMPORAL GAIT PARAMETERS, PELVIC MOVEMENTS AND PELVIC SYMMETRY DURING WALKING WITH SINGLE AND DUAL-TASKS IN INDIVIDUALS WITH CHRONIC IDIOPATHIC NECK PAIN

Purpose: Neck pain is associated with gait disturbances. The first aim of this study was to examine spatiotemporal gait parameters, pelvic movements and pelvic symmetry during single and dual task conditions in persons with Chronic Idiopathic Neck Pain (CINP) compared to healthy subjects (HS). The second aim was to investigate the relationship between disability and gait in persons with CINP.&#x0D; Methods: Thirty-one individuals with CINP (mean age 22.06±1.38 years, range 18-56 years) and 24 HS (mean age 22.60±1.51 years, range 18-43 years) participated in the study. CINP group completed Neck Disability Index. All participants performed 10-meter walking test in two conditions: (1) walking with head straight at usual speed, (2) walking with head straight at usual speed while carrying a tray. The BTS G-Walk wearable sensor was used to assess spatiotemporal parameters (speed, cadence, step length), pelvic movements (tilt, obliquity, rotation), and pelvic symmetry.&#x0D; Results: During single task gait, the CINP group had significantly lower walking speed, shorter stride length and worse pelvic tilt symmetry (p

Simulation of argon induced coupling coefficients of NH[formula omitted] doublets and their speed dependence

We present a theoretical evaluation of collision induced effects on a few typical doublets in the ν4 band of ammonia perturbed by argon. Quantum dynamical calculations performed on two NH3-Ar potential energy surfaces provide pressure broadening and intradoublet generalized cross sections. From these calculations we derive thermally averaged values at various temperatures. The intradoublet coupling terms at room temperature are found to be in good agreement with available data in the literature. In addition, we study the speed dependence of the pressure broadening and intradoublet coupling coefficients. The former show a usual speed dependence, quite important, but the later show a weak speed dependence at least around 296 K and above.

Assessment of Elderly Slips and Falls Utilising Induced Slip Training or An Obstacle Course

Background: Falls are a frequent reason for injury-related hospitalisation or mortality in older people. This research discusses a unique conceptual framework on dynamic stability and weight support in reducing the chance of falls and slips, based on induced slip training or an obstacle course principle. Objective: To find either an obstacle course or induced slip training for slips and falls in elderly people. Design: Berg Balance Scale and a modified timed up and go test study. Study setting: Community centres and communities in Agra and Mathura. Participants: A total of 30 subjects were selected based on the inclusion and exclusion criteria. Outcome measure: Obstacle course training and timed up &amp; go test were used as for assessing older people with balance and mobility issues. Results: In elderly people, the low friction surface trained group maintained their balance while walking at their usual speed in timed up and go. Conclusion: Based on findings of the study, the low friction surface group showed a faster time to walk over the same surface without losing balance. They were able to adjust their posture in response to the stresses by applying tactics learnt via repetition, resulting in more stable and safe movement. KEY WORD: Geriatric slips and falls, Induced slip, Obstacle course, Up and go test.

Microstructural effects on dynamic response of rigid and flexible pavements to moving load under plane strain

Granular soils and asphalt concrete materials are characterized by microstructural effects due to their micro-stiffness and micro-inertia. In this work, an attempt is made to investigate if the material microstructure in rigid and flexible pavements affects their dynamic response to loads moving with constant speed under conditions of plane strain and linearity. The rigid pavement is modeled by a homogeneous isotropic and linearly elastic with viscous damping flexural plate resting on a homogeneous isotropic microstructured linear elastic with hysteretic damping half-pane. The flexible pavement is modeled by a layered half-plane with linear isotropic microstructured layers. The top (asphalt concrete) layer is viscoelastic, while the other layers are elastic with hysteretic damping. The dynamic response of both of the above rigid and flexible pavement models to a distributed over a finite length moving load is obtained by using the complex Fourier series approach in conjunction with compatibility and equilibrium at the plate/soil (for rigid pavements) and soil layers (for flexible pavements) interfaces. The so obtained analytical/numerical response solutions for rigid and flexible pavement problems, after verification, are employed for conducting parametric studies in order to assess the microstructural effects on the response of those pavements to moving loads. It was found, at least for the pavement cases considered here, that the presence of the stiff plate in rigid pavements and the viscoelastic top layer in flexible pavements reduce considerably microstructural effects on the pavement response, rendering them not so important for usual vehicle speeds. However, for vehicle speeds very close to the critical speed, microstructural effects become very important.

A Hybrid-Excitation Synchronous Motor with a Change in Polarity

The hybrid-excitation permanent magnet (HEPM) motor is a synchronous motor characterized by a rotor that includes both permanent magnets and excitation windings. Thus, an active change in the magnetic flux by means of the excitation current is possible. In particular, the hybrid-excited rotor studied in this paper can be used to change the number of poles of the rotor itself. At the same time, the stator winding is also designed to perform a polarity change. The change in polarity allows users to obtain different torque versus speed characteristics with the same motor. In particular, a configuration with a lower pole number exhibits low torque at high speeds, while a configuration with a higher pole number produces high torque at low speeds. In this way, a single HEPM motor behaves like two different machines, extending the usual operating speed range of synchronous motors. In this paper, an HEPM rotor configuration is designed, and its performance is analyzed through finite element electromagnetic and thermal simulations.