Modification Of Width Research Articles

Influence of Walking Modification Strategies on Frontal Plane Hip Joint Moment and Gait Naturalness in Healthy Adults

OBJECTIVE: To evaluate the effects of lateral trunk lean and step width modification on hip adduction moment in healthy participants and examine their influence on walking naturalness. METHODS: Ten healthy participants underwent gait analysis under 4 walking conditions: natural walking, large trunk lean, doubled step width, and combined modification with slight trunk lean and 1.5 times step width. Early stance and late stance hip adduction moment were analyzed and compared using repeated-measures analysis of variance. Subjective naturalness of gait was also recorded. RESULTS: We observed a significant effect of walking condition on the hip adduction moment during early stance (F3,36 = 6.665, P = .001) and gait naturalness (F3,36 = 30.519, P<.001), but not hip adduction moment during late stance ( P = .733). Pairwise comparison indicated significantly reduced hip adduction moment during early stance with large trunk lean when compared to natural walking (36.7% less, P = .002, Cohen’s d = −1.41). Both combined and doubled step width modifications did not yield the expected hip adduction moment reduction ( P>.296). The perceived naturalness of the doubled step width modification was most comparable to natural walking ( P = .529), while the trunk lean modification was significantly less natural than natural walking and the least natural modification overall (81.1% less, P<.001, Cohen’s d = −4.34). CONCLUSION: Although trunk lean modification effectively reduces hip joint loading, it is perceived as the least natural pattern. Step width was more challenging to modify than trunk lean. JOSPT Open 2024;2(4):306-314. Epub 7 August 2024. doi:10.2519/josptopen.2024.0463

Step width modification to change rearfoot eversion and medial longitudinal arch angle during walking and running in individuals with pronated feet

BackgroundIndividuals with pronated feet often experience altered foot biomechanics, leading to increased risk of lower limb injuries. Step width modification has been proposed as a potential intervention to improve foot alignment during gait. Research questionDoes modifying step width influence rearfoot eversion and medial longitudinal arch angle (MLAA) in individuals with pronated feet during walking and running? MethodsTwenty individuals with pronated feet underwent analysis during walking and running on treadmill, maintaining increased or decreased step width using real-time visual feedback. Three-dimensional motion analysis measured rearfoot eversion and MLAA during the stance phase of gait. ResultsWide step width significantly reduced peak rearfoot eversion during waking (mean difference — with normal step width — (MD) = 3.6°, p < 0.001) and running (MD = 4.4°, p < 0.001), time to peak rearfoot eversion during walking (MD = 16.6 p < 0.001) and running (MD = 13.8°, p = 0.014), rearfoot eversion at touch down (TD) during walking (MD = 1.3°, p = 0.004), rearfoot eversion excursion during running (MD = 4.3°, p < 0.001), and peak MLAA during walking (MD = 2.9°, p = 0.006) and MLAA excursion during running (MD = 4.8°, p = 0.004).By contrast, during running, narrow condition significantly increased peak rearfoot eversion (MD = 3.4°, p < 0.001). During walking, time to peak rearfoot eversion (MD = 16.1, p < 0.001), rearfoot eversion at TD (MD = 1.4°, p = 0.008), rearfoot eversion excursion (MD = 5.9°, p < 0.001), and peak MLAA (MD = 3.4°, p < 0.001) were significantly increased. SignificanceThis study highlights the potential of step width modification as a simple yet effective intervention to improve foot biomechanics in pronated feet individuals during walking and running. Further research could lead to the development of personalized strategies for pronated feet individuals.

Examining the influence of magnetic field on a donor dopant’s photoionization cross-section in a double quantum box

This study systematically explored the binding energy and the photoionization cross-section (PCS) of a hydrogenic shallow donor impurity within a GaAs double quantum box structure incorporated into a Ga(1−x)Alx As matrix under the influence of an external intense magnetic field. The computations are performed using the effective-mass approximation (EMA) and the finite element method (FEM), taking into account a finite potential across all surfaces of the nanosystem. The results emphasize the significant role of the magnetic field, primarily in enhancing the donor binding energy within the double quantum box system. We demonstrate that increasing the magnetic field results in an augmentation of binding energy across various aluminum concentrations. The PCS of a shallow donor impurity undergoes a blue shift when shifted from the barrier center to the box center, attributed to the increased binding energy. When the double quantum box is subjected to a magnetic field effect, the amplitude peaks of PCS show an elevation coupled with a blue shift. By setting magnetic field values at 0 T, 35 T, or 70 T and varying aluminum concentrations, we observe a shift in the PCS towards higher energy levels along with an increase in peak amplitude. We also study the PCS of the donor impurity as a function of photon energy, mainly examining the effects of box width and barrier width modifications in the double quantum box.

Medium-Voltage Drives (MVD) - Performance Analysis of Seven-Level Cascaded H-Bridge Multilevel Driver

The drawbacks of traditional inverters, particularly in high-power applications and medium voltage, have been highlighted in previous investigations. Due to the cascaded H-bridge multilevel driver (CHBMD) harmonic characteristics improved and power enhanced, inverters with multiple levels are increasingly popular for high-power applications. The scientific literature has documented works on multilevel inverter topologies, control strategies, and applications. Additionally, no conclusive results investigate or rate a three-phase multilevel inverter's effectiveness. The present investigation evaluates the performance of a multi-carrier sinusoidal pulse width modification (MCS-PWM) based, Seven-Level cascaded H-bridge multilevel driver (7LCHBMD). Performance assessments develop based on the outcomes of a modeling experiment on the CHBMD functionality utilizing MATLAB. The characteristics of the results chosen to perform the task were the harmonic range, waveform arrangement, and essential significance reducing the THD output of the 7LCHBMD. The MCS-PWM technique procedure from the perspective of the voltage line had been determined according to the findings of the simulation investigation and analysis carried out for the 7LCHBMD utilizing the PD-PWM as the control framework.

Nanocomposites of ZnO Nanostructures and Reduced Graphene Oxide Nanosheets for NO2 Gas Sensing

A depletion region formed at the junction of two materials depends on the charge carrier concentration and the barrier height. The depletion width can be controlled by the overlayer thickness. Modification of the depletion width after gas exposure is mainly contributing to the sensor response. The maximum effect of gas molecules can be realized when the depletion width becomes comparable to the Debye length. Consequently, the selection of an appropriate overlayer thickness is very crucial. In the present work, chemiresistive gas sensing characteristics of ZnO nanowire (NW) films modified with different thicknesses of reduced graphene oxide (rGO) have been studied. The hybrid films showed selective outstanding NO2 response as compared to pure ZnO NW films. At an optimum rGO thickness of ∼15.3 nm, the response toward NO2 (with a minimum detection limit of 400 ppb) was found to be the highest that is nearly three times higher than that of pure ZnO nanowire films. A synergetic balance of the depletion width at the ZnO/rGO interface with the Debye length is attributed to the improved selective NO2 response of hybrid films.

Theoretical modelling of a deformation based concave square ring-square disc (SR-SD) silver structure for pressure sensing

A compact nanosensor that explores the tie-in between stress-induced deformation and optical resonance characteristics is theoretically proposed for pressure sensing. The structure modeling, electromagnetic (EM) wave simulation, and performance evaluations were carried out using the 2D finite element method (FEM). The proposed surface plasmon resonance (SPR) based metal-insulator-metal (MIM) model responds to the pressure induced on the top-facing side of an Ag concave square ring-square disc arrangement (Concave SR-SD) in terms of a structural curve-in into the insulator cavity. These deformations alter the electromagnetic field distributions and plasmonic resonance conditions, shifting the absorption cross-section profiles towards higher wavelengths. The shift in the resonant wavelength (Δλ) for specific measured deformations (d) exhibited by the normal SR-SD hinds at the application level perspective of the designed system in pressure sensing via its optomechanical correlation. Further, multiple parameters like insulator cavity width (W I ) and structure wise modifications in the outer ring structure are investigated for performance optimization, and subline sensitivity values (maximum) of 24.496 nm/MPa and 40.46 nm/MPa are observed from normal and concave SR-SD systems respectively. The suggested nano pressure sensor of suitable sensitivity and broad sensing range promises strong applicability in biomedicine, health monitoring, nanomechanics, chip-based devices, and nanoelectronics.

Roadside verges support greater ecosystem functions than adjacent agricultural land in a grassy woodland

Vegetation clearance is the major land use change in agricultural landscape, where woody species are removed to support agricultural production. Native woody species are now largely restricted to the thin strips along the road (roadside verges). Despite the importance of roadside verges as refugia for native species, their impacts on ecological functions and the driving factors have been little explored over extensive areas, limiting our capacity to argue for the retention and improvement of these ‘off-reserve’ habitats within agroecosystems. We compared the magnitude of ecological functions between paired roadside verges and adjacent agricultural land at 111 sites along a vegetation condition gradient in eastern Australia to examine the ecological importance of roadside verges and the potential regulators. Eighty-six percent of our 21 ecological attributes differed between roadsides and adjacent agricultural land, with roadside verges supporting greater carbon stocks, vegetation coverage, plant diversity, habitat complexity and tree recruitment, and were subject to less modification and erosion. These ecological effects strengthened with increasing roadside verge width, particularly for plant cover and diversity, the proportion of native plant species and habitat complexity. Management practices were major regulators of roadside functions, with roadside verge width and site modification negatively associated with tree recruitment and the soil organic carbon pool. Site modification and roadside verge width also indirectly reduced the soil organic carbon pool by either suppressing tree diversity or promoting the proportion of native plant species. Our study provides empirical evidence of the ecological importance of roadside verges in maintaining ecosystem functions and the sustainability of native plant communities in peri-agricultural landscapes. Our study also demonstrates the negative effects of site modification on tree recruitment and soil organic carbon pools, highlighting the importance of mitigating management activities (e.g., tree removal, fire, grazing) in the conservation of roadside verges.

Detection of highly overlapping peaks via adaptive apodization

Accurate peak detection is an essential component of many NMR tasks such as peak alignment, compound identification, and global spectral deconvolution. However, current peak detection approaches are generally limited by their ability to deal with spectral overlap, which has a deleterious effect on downstream data processing. In this work, we present the use of an adaptive apodization strategy that improves the detection of highly overlapping peaks. Sensitivity enhancement is used to identify general regions of interest and resolution enhancement is used to separate overlapping peaks, with parameters for both calculated directly from the data. Further limits on peak width help to reduce false positives. The method proposed in this work has been implemented in an open-source R package called rnmrfind that is available for download on GitHub (https://github.com/ssokolen/rnmrfind). A set of default parameters have been chosen to provide effective peak detection while keeping false positives to a minimum; however, application-specific tuning is possible through the modification of minimum peak width at half height (in Hz) and noise cutoff threshold (as a factor of estimated standard deviation). Comparison to existing packages rNMR and speaq on a series of 1H NMR spectra demonstrates improved peak resolution with little to no apparent drawbacks.

The Effects of the Width of an Isolated Valley on Near-Surface Turbulence

With the aim of ascertaining the effects of the widths (A) of valleys on near-surface turbulence, flows over an isolated symmetric three-dimensional valley of constant depth (H) and slopes are characterized in a large-boundary-layer wind tunnel. Starting at A = 4H, valley widths were systematically varied to A = 12H with constant increments of 2H. High-resolution laser-Doppler velocimetry measurements were made at several equivalent locations above each of the resulting valley geometries and compared with data from undisturbed flows over flat terrain. Flow separation caused by the first ridges generated inner-valley recirculation bubbles with lengths dependent on the valley widths. Secondary recirculation zones were also observed downstream from the crests of the second ridges. Results show that the width modifications exert the strongest effects on turbulence within the valleys and the vicinities of the second ridges. Above these locations, maximal magnitudes of turbulence are generally found for the larger width geometries. Furthermore, lateral turbulence overpowers the longitudinal counterparts nearest to the surface, with maximal gains occurring for the smaller widths. Our data indicate that valley widths are impactful on near-surface flows and should be considered together with other more established geometric parameters of influence.

Impact of subject-specific step width modification on the knee and hip adduction moments during gait.

Patients with hip osteoarthritis (OA) exhibit an increased step width (SW) during walking before and up to 2 years after total hip arthroplasty. Wider SW is associated with a reduction in the external knee adduction moment (KAM), but there is a lack of research regarding the effect of SW on the hip adduction moment (HAM). Is a wider SW an effective compensatory mechanism to reduce the hip joint loading? We hypothesized that (1) an increased SW reduces, (2) a decreased SW increases the KAM/HAM, and (3) secondary kinematic gait changes have an effect on the KAM/HAM. Twenty healthy individuals (24.0 ± 2.5 years of age) underwent instrumented gait analyses with 4 different subject-specific SW modifications (habitual, halved, double, and triple SW). The resulting external KAMs and HAMs were compared using statistical parametric mapping (SPM). Post hoc testing demonstrated significantly lower HAM for both the double (p < 0.001, 15-31 % and 61-98 % of the stance phase) and the triple SW (p < 0.001, 1-36 % and 58-98 %) compared to the habitual SW. The extent of the reduction at the first and second peak was comparable for HAM (15-25 % reduction) and less pronounced at the first peak of KAM (9-11 % reduction) compared to the second peak of KAM (19-28 % reduction). In contrast, halving the SW did not lead to a significant change in KAM or HAM compared to the habitual SW (p > 0.009). An increase in SW is an effective and simple gait mechanism to reduce the frontal plane knee and hip joint moments. However, hypothesis 2 could not be confirmed, as halving the SW did not cause a significant change in KAM or HAM. Given the results of the present study, gait retraining with regard to an increased SW may be an adequate, noninvasive option for the treatment of patients with hip OA.

Effects of step width modifications on the ambulatory kinetics in patients with medial knee osteoarthritis

Purpose: Gait retraining is a promising intervention to improve the mechanical loading of the knee in patients with medial osteoarthritis (OA). Specifically, it could reduce the peak knee adduction moment (pKAM) without increasing the peak knee flexion moment (pKFM), which are the kinetic changes most frequently sought in patients with medial knee OA. Various approaches have been proposed to help the patients achieve this dual kinetic change, but more work is needed to determine how to implement gait retraining at best.

High-power operation and lateral divergence angle reduction of broad-area laser diodes at 976 nm

Broad-area diode lasers with high output power and low lateral divergence angle are highly desired for extensive scientific and industrial applications. Here, we report on the epitaxial design for higher output power and a flared waveguide design for reduced divergence, which leads to high power operation with a low lateral divergence angle. A vertically asymmetric epitaxial structure was employed and optimized for low internal optical loss and high efficiency to realize high output power operation. Using a flared waveguide design, the lateral divergence angle was efficiently reduced by decreasing the number of high-order lateral optical modes significantly. The flared waveguide design introduces a smooth modification of the ridge width along the cavity without deteriorating laser performance. Based on the optimized epitaxial and waveguide design, we scaled the waveguide width to realize high continuous-wave power of 34.5 W at 25 °C. A low lateral divergence angle of 8° and high power conversion efficiency of 60% were achieved at the operating power level of 25 W. The life test data (30 A at 45 °C for 39 units, 0 failures in 1000 h) demonstrated reliable operation illustrating the efficient design for reduced lateral divergence angle and high operating power.

Optimization of distributed axial dynamic modification based on the dynamic characteristics of a helical gear pair and a test verification

In this paper, a method for the dynamic modification of tooth width is used to optimize the problem of uneven loading of helical gears. Considering the meshing error caused by gear manufacturing, installation, time-varying meshing stiffness, clearance, and shaft bending, the distributed meshing transverse-torsion-pendulum nonlinear dynamic model of a helical gear pair is established. A method to modify the tooth width of the helical gear pair is proposed to optimize the uniform load characteristics of the tooth surface. Through the research of dynamic tooth width modification, the optimal modification parameters are obtained so that the dynamic load distribution of the tooth surface is uniform and the load distribution centre is close to the centre of the tooth surface, which reduces the swing phenomenon. During experimental testing, the swing vibration response of the modified gear is reduced by a maximum of 26.15%, the dynamic load coefficient is reduced by a maximum of 20.84%, and the stress distribution on the tooth surface is uniform.

Modification of barrier height and depletion layer width of methyl red (MR) dye-based organic device in the presence of single-walled carbon nanotubes (SWCNT)

In this paper, barrier height ( $$\phi_{{\text{b}}}$$ ) and depletion layer width (Wd) of ITO-coated glass/Methyl Red (MR) dye/Aluminum (Al)-based organic device have been studied, and effect of single-walled carbon nanotubes (SWCNT) on both of these parameters has been observed. ITO-coated glass as front electrode and Aluminum as back electrode are used to form the device by using spin coating technique. $$\phi_{{\text{b}}}$$ is calculated by analyzing both I–V and C–V characteristics. In the presence of SWCNT, $$\phi_{{\text{b }}}$$ is reduced from 0.870 ± 0.05 eV to 0.754 ± 0.05 eV in I–V characteristics and from 0.850 ± 0.12 eV to 0.784 ± 0.12 eV in C–V characteristics. $$\phi_{{\text{b }}}$$ is also estimated by Norde method, which shows the presence of SWCNT lowers the value of $$\phi_{{\text{b }}}$$ from 0.852 eV to 0.738 eV. Wd has been calculated from C–V characteristics. With SWCNT, value of Wd reduces from (8.74 ± 0.02) × 10−6 cm to (7.85 ± 0.02) × 10−6 cm. Threshold voltage also decreases from 2.52 V to 1.99 V in the presence of SWCNT. Addition of SWCNT within device ameliorates charge injection by lessening $$\phi_{{\text{b}}}$$ and Wd of the device.

Gap width modification on fully screen-printed coplanar Zn|MnO2 batteries

Fully printed primary zinc-manganese dioxide (Zn|MnO2) batteries in coplanar configuration were fabricated by sequential screen printing. While electrode dimensions and transferred active masses were kept at constant levels, electrode separating gaps were incrementally enlarged from 1 mm to 5 mm. Calendering of solely zinc anodes increased interparticle contact of active material within the electrodes while the porosity of manganese dioxide based electrodes was maintained by non-calendering. Chronopotentiometry revealed areal capacities for coplanar batteries up to 2.8 mAh cm−2. Galvanostatic electrochemical impedance spectroscopy measurements and short circuit measurements were used to comprehensively characterise the effect of gap width extension on bulk electrolyte resistance and charge transfer resistance values. Linear relationships between nominal gap widths, short circuit currents and internal resistances were evidenced, but showed only minor impact on actual discharge capacities. The findings contradict previous assumptions to minimise gap widths of printed coplanar batteries to a sub-millimetre range in order to retain useful discharge capacities. The results presented in this study may facilitate process transfer of printed batteries to an industrial environment.

Effects of Increased Step-Width on Knee Biomechanics During Inclined and Declined Walking.

The purpose of this study was to investigate effects of preferred step width and increased step width modification on knee biomechanics of obese and healthy-weight participants during incline and decline walking. Seven healthy-weight participants and 6 participants who are obese (body mass index ≥ 30) performed 5 walking trials on level ground and a 10° inclined and declined instrumented ramp system at both preferred and wide step-widths. A 2 × 2 (step-width × group) mixed-model analysis of variance was used to examine selected variables. There were significant increases in step-width between the preferred and wide step-width conditions for all 3 walking conditions (all P < .001). An interaction was found for peak knee extension moment (P = .048) and internal knee abduction moment (KAM) (P = .025) in uphill walking. During downhill walking, there were no interaction effects. As step-width increased, KAM was reduced (P = .007). In level walking, there were no interaction effects for peak medial ground reaction force and KAM (P = .007). There was a step-width main effect for KAM (P = .007). As step-width increased, peak medial ground reaction force and peak knee extension moment increased, while KAM decreased for both healthy weight and individuals who are obese. The results suggest that increasing step-width may be a useful strategy for reducing KAM in healthy and young populations.

Sensitivity of SET Pulse-Width and Propagation to Radiation Track Parameters in CMOS Inverter Chain

Single-event transient (SET) due to heavy-ion strike is a serious reliability concern for devices operated in radiation environment. Due to technology scaling, nodal capacitance decreases which increases the SET vulnerability. In this paper, the sensitivity of SET pulse width in 45 nm bulk and SOI MOSFET to linear energy transfer (LET), heavy-ion track length, angle of strike, characteristic radius, and characteristic time of the track is analysed. The modification of SET pulse width while propagating through 45 nm bulk-and SOI-based CMOS chain of inverters and its dependence on aforementioned radiation parameters is also analysed. The results show that all the pulses produced in SOI-based inverter chain get attenuated during propagation and do not reach the last stage. However, in the case of bulk, any SET having pulse width greater than 37 ps (measured using full width at half maximum) propagates and reaches the last stage of the inverter chain. Thus, the SOI devices are more immune to SET compared to the bulk, for different heavy-ion track parameters.

Positive and negative linear chirping of Gaussian pulses in non-dispersive dielectric layers

In this work, the first and second order effects for reflected and transmitted pulses with a Gaussian distribution of frequencies are analytically developed and interpreted. They show some peculiar characteristics that bear certain parallelism with those of monochromatic beams with a Gaussian distribution of amplitudes. However, when the former are considered, the results of the first and second order effects obtained analytically are more difficult to interpret and are clearly limited by the principle of causality. We show that pulses show some peculiar characteristics when they reflect and transmit through linear media: time delay, shifting of the mean frequency and modification of the pulse width. In addition to these effects we show and analyze the unexpected presence of chirping when a simple structure of non-dispersive materials is considered.

Modifying Stride Length in Isolation and in Combination With Foot Progression Angle and Step Width Can Improve Knee Kinetics Related to Osteoarthritis; A Preliminary Study in Healthy Subjects.

The purpose of this study was to determine the effects of modifying stride length (SL) on knee adduction and flexion moments, two markers of knee loading associated with medial-compartment knee osteoarthritis (OA) progression. This study also tested if SL modifications, in addition to foot progression angle (FP) and step width (SW) modifications, provide solutions in more subjects for reducing knee adduction moment (KAM) without increasing knee flexion moment (KFM), potentially protecting the joint. Fourteen healthy subjects (six female) were enrolled in this preliminary study. Walking trials were collected first without instructions, and then following foot placement instructions for 50 combinations of SL, FP, and SW modifications. Repeated measures analysis of variance was used to detect group-average effects of footprint modifications on maximum KAM and KFM and on KAM impulse. Subject-specific dose-responses between footprint modifications and kinetics changes were modeled with linear regressions, and the models were used to identify modification solutions, per subject, for various kinetics change conditions. Shorter SL significantly decreased the three kinetics measures (p < 0.01). Potential solutions for 10% reductions in maximum KAM and KAM impulse without increasing maximum KFM were identified for five subjects with FP and SW modifications. A significantly higher proportion of subjects had solutions when adding SL modifications (11 subjects, p = 0.04). In conclusion, SL is a valuable parameter to modify, especially in combination with FP and SW modifications, to reduce markers of medial knee loading. Future work is needed to extend these findings to osteoarthritic knees.

Design optimisation of mating helical gears with profile shift using nature inspired algorithms

ABSTRACT Profile shift of the gear significantly affects its form, zone, stress factors, transversal and face load factors. In this paper, an optimum solution to the problem of mating helical gears design considering profile shift is given. The objective of the problem is to minimise volume taking into account tooth root bending strength, contact pressure, face width, and addendum modification coefficients as constraints. The design variables, namely, the module, the face width, the number of teeth, and profile shift coefficients of both gears are considered. Nature-inspired algorithms, namely, Simulated Algorithm (SA), Fire Fly Algorithm (FA), Cuckoo Search (CS), Particle Swarm Optimisation (PSO) and Teaching Learning-Based Optimisation (TLBO) algorithms are employed. Results of simulation with and without profile shift, performance of various algorithms are analysed and validated with literature. Results show that CS and PSO algorithms give the best optimum volume. They also significantly reduce volume by 1.91%, when compared to literature. CS algorithm gives the best optimum design parameters. Furthermore, results show the volume of the mating helical gears with profile shift is much lesser than the pair without profile shift.