Effect Of Alignment Research Articles

Effectiveness and efficiency of tool alignment and simultaneity factors on double-sided friction stir welding for joining heat-treatable aluminum alloys: a review

Effectiveness and efficiency of tool alignment and simultaneity factors on double-sided friction stir welding for joining heat-treatable aluminum alloys: a review

Effect of tibiofemoral alignment on simulated knee contact forces during gait in mechanically and kinematically aligned total knee arthroplasty patients.

The goal of the study was to apply a musculoskeletal knee model that considers individual tibiofemoral alignment (TFA) and to investigate its effect on knee contact force (KCF) during gait in mechanically (MA) and kinematically aligned (KA) total knee arthroplasty (TKA) patients. Total, medial, and lateral KCF was estimated from pre- and postoperative gait data of TKA patients (MA: n = 26, KA: n = 22). Preoperative KCF was compared between the generic and the adapted model using t-tests and statistical parametric mapping (SPM). The TFA-adapted model was then used to analyze pre- to postoperative differences in MA and KA patients. The factor of TFA increased estimates of KCF during the stance phase and led to higher peak contact forces (3-5%, p < 0.05). SPM analyses of pre- to postoperative KCF revealed no significant differences across the gait cycle, however, postoperative peak KCF was significantly increased in both groups (10-18%, p < 0.05). No group differences were observed when comparing KCF between MA and KA patients. Integrating TFA into the model led to higher estimations of KCF. Applying the adapted model, pre- to postoperative differences in KCF were the same for both TKA groups suggesting that both alignment techniques had comparable effects on knee loading post-TKA.

On the Effect of Fibre Orientation and MWCNTs on the Strain‐Sensing Performance of TPU/PANI Electrospun Nanofibres

ABSTRACTThe increasing demand for flexible electromechanical devices with superior stretchability, durability, thermal stability and sensitivity has driven the development of new smart functional materials to replace conventional semiconductors. This study utilises combining electrospinning and in situ polymerisation to fabricate four types of thermoplastic polyurethane/polyaniline (TPU/PANI) nanofibrous membranes with varied fibre orientation and multiwalled carbon nanotubes (MWCNTs) incorporation. The combined effects of material composition and fibre alignment on strain‐sensing performance were systematically explored. All membranes exhibited stable, symmetric ohmic behaviour under strain, with current decreasing as strain increased. Remarkable repeatability and stability were observed in cyclic current–time tests. MWCNTs addition significantly enhanced conductivity, with aligned fibres further boosting performance. Gauge factor (GF) measurements revealed that aligned TPU/PANI mats had GFs of 7 (0%–18% strain) and 14.3 (18%–40%), while aligned TPU/MWCNTs/PANI mats had GFs of 5.2 (0%–13%) and 7.3 (13%–40%). Random TPU/PANI mats showed GFs of 13.9 (0%–11%) and 23.3 (11%–40%) and random TPU/MWCNTs/PANI mats had GFs of 13.9 (0%–19%) and 24.7 (19%–40%). Each configuration demonstrated suitability for specific applications, with random TPU/MWCNT/PANI mats exhibiting the best overall performance. This research provides critical insights into optimising flexible strain sensors by tuning both material composition and fibre orientation.

The effects of CNT type, alignment and dopants on piezoresistance in CNT fibres

The effects of CNT type, alignment and dopants on piezoresistance in CNT fibres

Multi-source domain adaptation for EEG emotion recognition based on inter-domain sample hybridization.

Electroencephalogram (EEG) is widely used in emotion recognition due to its precision and reliability. However, the nonstationarity of EEG signals causes significant differences between individuals or sessions, making it challenging to construct a robust model. Recently, domain adaptation (DA) methods have shown excellent results in cross-subject EEG emotion recognition by aligning marginal distributions. Nevertheless, these methods do not consider emotion category labels, which can lead to label confusion during alignment. Our study aims to alleviate this problem by promoting conditional distribution alignment during domain adaptation to improve cross-subject and cross-session emotion recognition performance. This study introduces a multi-source domain adaptation common-branch network for EEG emotion recognition and proposes a novel sample hybridization method. This method enables the introduction of target domain data information by directionally hybridizing source and target domain samples without increasing the overall sample size, thereby enhancing the effectiveness of conditional distribution alignment in domain adaptation. Cross-subject and cross-session experiments were conducted on two publicly available datasets, SEED and SEED-IV, to validate the proposed model. In cross-subject emotion recognition, our method achieved an average accuracy of 90.27% on the SEED dataset, with eight out of 15 subjects attaining a recognition accuracy higher than 90%. For the SEED-IV dataset, the recognition accuracy also reached 73.21%. Additionally, in the cross-session experiment, we sequentially used two out of the three session data as source domains and the remaining session as the target domain for emotion recognition. The proposed model yielded average accuracies of 94.16 and 75.05% on the two datasets, respectively. Our proposed method aims to alleviate the difficulties of emotion recognition from the limited generalization ability of EEG features across subjects and sessions. Though adapting the multi-source domain adaptation and the sample hybridization method, the proposed method can effectively transfer the emotion-related knowledge of known subjects and achieve accurate emotion recognition on unlabeled subjects.

Modeling the effects of crystallite alignment on birefringent light scattering in transparent polycrystalline aluminum oxide

Transparent alumina ceramics are known for high toughness and the ability to withstand high temperatures, making them ideal materials for use in extreme environments and high-power optical devices. However, polycrystalline alumina, which has a hexagonal crystal structure, is difficult to make highly transparent due to birefringent scattering loss. Research has shown that birefringent scattering can be reduced by having finer grains and/or aligned grains. Here, we present an analytical birefringence scattering model that can model realistic microstructures, by including chord length distributions and grain orientations, and predict the birefringence scattering loss quantitatively. Our modeled results match well with existing experimental data for transparent fine grained and aligned alumina. This model is derived from first-principles and is applicable to other transparent ceramics.

Full‐field effect of flow‐induced fiber orientation during compression molding of carbon fiber sheet molding compounds

AbstractAn image‐based fiber orientation analysis technique has been employed to study the effect of initial charge coverage and preferential fiber alignment on the flow‐induced fiber orientations in carbon fiber sheet molding compounds (SMCs). The initial charge coverage area exhibited minimal fiber reorientation while significant fiber alignment in the flow direction was observed in the regions of greatest flow. Novel subsurface analysis using the same full‐field orientation analysis technique also showed the presence of a skin‐core structure with greater flow‐induced fiber alignment at the mold surfaces, while the core retained more of the initial fiber orientation distribution. Edge effects were also revealed by this analysis at the mold walls. Tensile testing from two orthogonal directions showed that panels molded from lower charge coverage resulted in better mechanical performance and lower anisotropy. Moreover, by encouraging charge flow in the preform's preferential alignment direction, high tensile stiffness and strength in the preferred direction were achieved (56.7 GPa and 238.9 MPa, respectively) at 30% fiber volume fraction. This provides a practical demonstration of the value in controlling fiber orientation, with respect to charge positioning and mold flow, to maximize and tailor the composite performance of SMCs typically used for automotive applications.Highlights Low‐cost scanning technique is extended to assess internal fiber orientations Full‐field orientations are measured before and after molding Investigation of how charge size and shape can affect orientations Combining effects of flow and initial orientation to tailor SMC performance Circular statistics provides a thorough analysis of orientation distributions

Investigating the mechanical properties of composites containing exfoliated graphite/epoxy sensors: Experimental testing and simulation

One approach to structural health monitoring (SHM) involves embedding sensors within a composite material. However, the integration of these sensors can potentially introduce flaws that might affect the composite’s mechanical properties. This research aims to explore the impact of embedding exfoliated graphite (EG)/epoxy sensors on the mechanical characteristics of composite systems through laboratory experiments and numerical simulations. Sensor strips composed of varying volume fractions of EG/epoxy were fabricated. Tensile test specimens were prepared by embedding these sensors in the epoxy matrix oriented both lengthwise and widthwise. Baseline specimens of EG/epoxy without sensors were also created for comparison. Tensile tests were performed on the samples to evaluate the effects of the embedded sensors on the composite’s elastic modulus and tensile strength. The results indicated a slight improvement in both elastic modulus and tensile strength with the introduction of EG. Crucially, the orientation of the sensors within the samples had a significant impact on the composite’s mechanical properties. Samples with widthwise-aligned sensors showed reduced tensile strength due to delamination along the sensor edges. Finite element simulations using a viscoelastic model based on the experimental data were conducted to analyze the effect of sensor alignment on mechanical properties. The findings revealed that a grid pattern alignment of sensors significantly enhanced mechanical performance compared to lengthwise or widthwise alignment, particularly at 0.1% and 0.3% EG volume fractions, highlighting the effectiveness of a grid pattern for embedding sensors in SHM applications.

Elliptically polarized high-order harmonic generation from N[formula omitted]-CO mixed gases

We theoretically study the elliptically polarized high-order harmonic generation from N2-CO mixed gases. Our simulations show that the polarization of HHG is highly sensitive to both the mixing ratio and molecular alignment angle. In particular, even a small addition of CO gas results in a significant enhancement of harmonic ellipticity compared to pure N2 gas. Under a proper mixing ratio and molecular alignment angle, a large ellipticity of HHG is observed, which is larger than that in reported N2-Ar mixture. Furthermore, when considering the molecular alignment effect, the dependence of ellipticity of HHG on mixing ratio exhibits slight variations. These findings pave the way for generating elliptically polarized extreme ultraviolet pulses.

Fiber Alignment's Effect on the Properties of Hybrid Glass/Flax Fiber‐Reinforced Epoxy Composite Laminates

ABSTRACTIn this study, glass fiber and flax fiber reinforced with epoxy and ZnO nanofiller were used to create composites utilizing the hand layup method. The purpose of this study is to develop a novel hybrid polymer‐matrix composite that can be employed in various application areas such as aerospace, sports, medical equipment, railways, etc. The fabricated composite was made with epoxy as a matrix material reinforced with nano‐ZnO, glass fiber, and flax fiber. Six fiber layers with varying fiber orientations were inserted into the matrix in a specific stacking order. The results show the maximum tensile, flexural, impact, and ILSS as the values of 264.74 MPa, 492.12 MPa, 595.72 J/m, and 50.05, respectively. Along with the mechanical properties, Physical characterization such as density, void content, thickness swelling, moisture content, and water absorption tests were conducted. FE‐SEM test was conducted to check the uniformity of nanoparticles in the matrix material and the breakdown of fibers.

Altering prosthetic alignment does not affect hip and low back joint loading during sit-to-stand in people with a transtibial amputation

People with a transtibial amputation (TTA) have greater prevalence of low back and hip joint pain compared to the general population. Altered movement, loading patterns, and neuromuscular activation during daily tasks like sit-to-stand likely contribute to these high rates of pain. In addition, muscle activation, ground reaction forces, and trunk range of motion can be affected by prosthetic alignment during sit-to-stand. However, it is unclear how prosthetic alignment affects joint contact forces during this task. The purpose of this study was to investigate the effect of prosthetic alignment on hip and low-back joint loading in people with TTA during sit-to-stand. Kinematics, ground reaction forces, and muscle activity data were collected from 10 people with TTA and 10 age- and sex- matched individuals without limb loss during five self-paced sit-to-stand trials. Participants with TTA completed the sit-to-stand task with their prescribed alignment and six altered alignment conditions (±10 mm anterior/posterior, medial/lateral, and ± 20 mm short/tall). A musculoskeletal model was used to calculate hip and L4-L5 joint loading. There were no differences in hip or L4-L5 joint loading between alignments. Participants with TTA had a greater peak hip joint contact force on the intact side hip compared to the amputated side hip across all alignments. Participants with TTA had greater L4-L5 joint contact force compared to those without amputation. While prosthetic alignment did not affect joint loading during sit-to-stand, future work on additional dynamic tasks is needed to better understand the potential role of prosthetic alignment on joint loading.

Effect of surface alignment on electric-field-induced phase transitions in blue phases

This study investigates the critical electric field thresholds required for phase transitions in the blue phases of liquid crystals (BPs) confined within vertical field switching cells. BPs are attractive for electro-optical applications due to their polarization-independent response and fast switching times; however; challenges remain regarding their limited temperature stability and previously reported high operational voltages. We employ a combined approach of polarized optical microscopy and electrical impedance analysis to identify the electric field thresholds triggering BP transitions to focal conic domains in cells with and without planar polyimide alignment layers. We show that surface alignment layers stabilize the blue phases and allow for higher applied electric fields before transitioning into the focal conic state. This suggests the possibility of a wider operational voltage range in thinner cells with alignment layers. These findings significantly improve our understanding of BPs, addressing key challenges and paving the way for their integration into advanced photonic devices, based on the CMOS technology.

Strategic Management Practices in Multinational Corporations: A Comparative Study

This paper explores strategic management practices within multinational corporations (MNCs) through a comparative study of different regional and industrial contexts. The research aims to identify key strategies that drive success and sustainability in a globalized business environment. Utilizing a mixed-method approach, the study combines quantitative analysis of financial performance metrics with qualitative insights from interviews with senior executives. The findings highlight the significance of adaptive strategies, cultural intelligence, and robust risk management frameworks. Additionally, the study uncovers regional variations in strategic priorities, emphasizing the need for MNCs to tailor their approaches to local market conditions. The paper concludes with recommendations for practitioners to enhance strategic alignment and operational effectiveness across diverse geographical landscapes.

Spatiotemporally modulated full-polarized light emission for multiplexed optical encryption

Spatiotemporal control of full freedoms of polarized light emission is crucial in multiplexed optical computing, encryption and communication. Although recent advancements have been made in active emission or passive conversion of polarized light through solution-processed nanomaterials or metasurfaces, these design paths usually encounter limitations, such as small polarization degrees, low light utilization efficiency, limited polarization states, and lack of spatiotemporal control. Here, we addressed these challenges by integrating the spatiotemporal modulation of the LED device, the precise control and efficient polarization emission through nanomaterial assembly, and the programmable patterning/positioning using 3D printing. We achieved an extremely high degree of polarization for both linearly and circularly polarized emission from ultrathin inorganic nanowires and quantum nanorods thanks to the shear-force-induced alignment effect during the protruding of printing filaments. Real-time polarization modulation covering the entire Poincaré sphere can be conveniently obtained through the programming of the on-off state of each LED pixel. Further, the output polarization states can be encoded by an ordered chiral plasmonic film. Our device provides an excellent platform for multiplexing spatiotemporal polarization information, enabling visible light communication with an exceptionally elevated level of physical layer security and multifunctional encrypted displays that can encode both 2D and 3D information.

Research on Multi-Modal Music Score Alignment Model for Online Music Education

As music data storage becomes increasingly diverse in the era of big data, ensuring alignment of music works with the same semantics for online music education is crucial. To achieve this, a multi-modal music score alignment algorithm model based on deep learning was developed and optimized. Experimental results demonstrated that Note + DCO feature combination yielded the best MIDI input characteristics (mean value: 13.27 ms), whereas CQT feature comparison produced the best results for audio input (average: 12.85 ms). The ResNet-34 network was noted to have the most effective music score alignment effect with alignment errors averaging less than one frame. Compared with other algorithms, the proposed algorithm had the lowest average value of 9.28 ms, median value of 5.85 ms, and standard deviation of 20.17 ms. Actual music retrieval showed a Top-1 retrieval accuracy of 10.93% that was close to 11%. Overall, the proposed algorithm is significant for score alignment and music retrieval recognition in online music education.

Investigation of the effect of the alignment of the eye and the virtual image of virtual reality on fatigue in viewing VR device

AbstractCybersickness is a major problem hindering the use of fully immersive virtual reality (VR) systems. A mismatch between the interpupillary distance (IPD) and the inter‐optical system distance (IOSD) can cause discomfort when using VR devices. To solve this, the IOSD must be aligned according to the user's IPD. Herein, we investigated the effects of the optimum alignment of IPD and IOSD on eye fatigue when using VR systems. A method was used such that the IPD and IOSD for each participant were initially aligned under the condition that binocular fusion did not occur by displaying different left and right images. Fifteen university students aged 20–26 years were included. In the alignment and misalignment states, a symptom questionnaire was used to evaluate changes in the symptoms of participants after viewing a short movie using the VR device. We found that the obtained results in the eye strain category were statistically improved in the aligned state compared with those in the misaligned state. However, there were no significant differences in the general discomfort, nausea, focusing difficulty, or headache categories. Consequently, we confirmed that the alignment of the VR device using the proposed method can reduce eye fatigue when viewing VR content.

Synergistic Effect of Defects Passivation and Energy Level Alignment Realizing P3HT-Based High-Efficiency CsPbI3 Perovskite Solar Cells.

Poly (3-hexylthiophene) (P3HT) is one of the most efficient hole transport layers (HTLs) in perovskite solar cells (PSCs). However, surface and boundary defects in CsPbI3, and energy level mismatch between CsPbI3 and P3HT lead to a low power conversion efficiency (PCE) in P3HT-based CsPbI3 PSCs. Here, a synergistic strategy with anti-solvent (sec-pentyl alcohol, 2-PA) and passivators (LiX, X = F, Cl, Br, I) is developed to promote the photovoltaic performance of P3HT-based CsPbI3 PSCs. It is proved that the 2-PA washes away the residual DMF and DMAPbI3, and assists the secondary growth of CsPbI3 crystal. LiX not only can passivate iodine (I) vacancies, but also can reduce energy offset at CsPbI3/P3HT interface, accelerating hole extraction process. Finally, an impressive efficiency of 19.26% is obtained due to the synergistic effect of defects passivation and energy alignment, which is 34.4% higher than the 14.32% achieved in Control cell. These findings prove that synergistic strategy of defects passivation and energy alignment is an effective way for realizing high-efficiency in P3HT-based CsPbI3 PSCs.

Proton conductivity and dielectric studies on chitosan/polyvinyl alcohol blend electrolytes: Synergistic improvements with ionic liquid and graphene oxide

This study investigates the impact of ionic liquid, 1-methylimidazolium tetrafluoroborate (IL) and graphene oxide (GO) on the performance of chitosan/polyvinyl alcohol (CS/PVA)-based composite electrolytes. Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) confirm the successful incorporation of IL and GO, affecting the structural and morphological properties of the electrolytes. Thermogravimetric analysis (TGA) reveals enhanced thermal stability in GO-doped samples, with increased residual weight at high temperatures, while IL addition leads to higher initial weight loss due to its hygroscopic nature. Ionic conductivity measurements demonstrate that the CS/PVA/IL-GO(4.0) composite achieves the highest proton conductivity of 1.76 × 10−3 S/m at 300 K and 1 MHz, surpassing other samples and aligning with top values reported in literature. Dielectric studies show a significant increase in dielectric constant to 9.55 × 104 at 300 K and 20 Hz for CS/PVA/IL-GO(4.0), attributed to enhanced dipole alignment and polarization effects. The loss tangent analysis indicates the shortest relaxation time of 2.07 × 10−4 s for CS/PVA/IL-GO(4.0), correlating with its superior proton conductivity. These findings highlight the potential of CS/PVA/IL-GO electrolytes for advanced energy storage and conversion applications, suggesting further research into GO dispersion and long-term stability for optimized performance in practical devices.

Automatic alignment of elastic slender belt caused by crown roller in two-roller belt system

To clarify the relationship between the geometry of the crown roller and the automatic alignment of the belt in a two-roller belt system that includes a crown roller, we develop an analytical method that calculates the lateral belt position. The calculated results based on this method are in good agreement with the experimental results, thereby validating the analysis method developed. The automatic alignment of the belt is caused by the difference in the peripheral speed of the crown roller in the axial direction. The automatic alignment effect improves as the radius of curvature and the diameter of the crown roller decrease. Furthermore, we show that the effect of belt tension on the automatic alignment of the belt has a slight effect on the time until the belt moves to the roller center position but does not have a significant effect on the automatic alignment of the belt.

Laser wireless power transfer system design for lunar rover

In order to address the future power generation needs for scientific exploration of the lunar permanently shadowed regions, this paper proposes a laser wireless power transfer (LWPT) system from a power source at the illuminated rim of the crater to a photovoltaic laser receiver on a rover exploring inside the permanently shadowed region. To fill a gap between the conceptual design and an operational system, the required conditions were analyzed regarding the effects of beam alignment and shaping, wavelength-dependent conversion efficiency on the system level efficiency, and a ground-based prototype system was established. Electric–electric efficiency of 11.55% was measured at a ground transmission distance of 10 m. The study is complemented by discussing optimization analysis for subsequent research, can be more effective and employed in the future.