Relative Orientation Research Articles

Reactive Collision Avoidance Control for Nonholonomic Vehicles and Obstacles of Arbitrary Shape

Abstract Potential field-based collision avoidance algorithms for mobile robots frequently assume vehicles and obstacles to have circular or spherical shapes. This assumption not only simplifies the analysis but also limits the mobility of agents in confined spaces, particularly for vehicles with elongated or irregular shapes. To increase mobility, this letter presents a decentralized collision avoidance framework for nonholonomic systems of unicycle type that considers the non-circular shape and relative orientation of vehicles and obstacles. The framework builds on the concepts of potential field and avoidance functions. However, it proposes using a non-constant minimum safe distance radius that changes based on the shape, relative position, and relative orientation of agents. The control framework is proven to guarantee collision avoidance at all times and is shown, via simulation, to increase the ability of agents to navigate through narrow spaces safely.

Domain Swapping in Abiotic Foldamers.

Foldamer sequences that adopt tertiary helix-turn-helix folds mediated by helix-helix hydrogen bonding in organic solvents have been previously reported. In an attempt to create genuine abiotic quaternary structures, i.e. assemblies of tertiary structures, new sequences were prepared that possess additional hydrogen bond donors at positions that may promote an association between the tertiary folds. However, a solid state structure and extensive solution state investigations by Nuclear Magnetic Resonance (NMR) and Circular Dichroism (CD) show that, instead of forming a quaternary structure, the tertiary folds assemble into stable domain-swapped dimer motifs. Domain swapping entails a complete reorganization of the arrays of hydrogen bonds and changes in relative helix orientation and handedness that can all be rationalized.

Experimental demonstration of positioning the cooperation terminal for underwater wireless optical communication based on visual navigation

Underwater wireless optical communication (UWOC) is a useful way to transmit a large volume of data in ocean engineering. In application, one of the UWOC terminals is usually carried on an underwater robot to actively adjust its orientation and position to establish an optical link, which requires the mobile terminal to locate the cooperation partner. At a short communication distance, visual navigation is a preferred method to measure the position. In this method, a camera is installed on the mobile terminal while several light-emitting diodes (LEDs) are in the cooperation one. In the image of the camera, by capturing the pattern formed of LEDs light spots, the relative position and orientation between terminals could be calculated. However, in a UWOC system, visual navigation is interfered with by the UWOC transmitter since it forms an additional light spot in the camera’s image. To solve this issue, we present a UWOC-compatible visual navigation method, in which the UWOC light spot is distinguished with the hue, saturation, and value (HSV) color model. Then, we experimentally demonstrate the effectiveness of the method in a pool, applying signals with different bitrates and power on the transmitter. The results show that, while the distance between terminals is within 350 cm and the yaw angle is within 5°, the measured errors are within 1.77 cm and 0.92°, respectively, which is accurate enough for most UWOC applications. The method presented in this paper is simple, pragmatic, and useful for establishing a UWOC link.

Domain Swapping in Abiotic Foldamers

AbstractFoldamer sequences that adopt tertiary helix‐turn‐helix folds mediated by helix‐helix hydrogen bonding in organic solvents have been previously reported. In an attempt to create genuine abiotic quaternary structures, i.e. assemblies of tertiary structures, new sequences were prepared that possess additional hydrogen bond donors at positions that may promote an association between the tertiary folds. However, a solid state structure and extensive solution state investigations by Nuclear Magnetic Resonance (NMR) and Circular Dichroism (CD) show that, instead of forming a quaternary structure, the tertiary folds assemble into stable domain‐swapped dimer motifs. Domain swapping entails a complete reorganization of the arrays of hydrogen bonds and changes in relative helix orientation and handedness that can all be rationalized.

German and Italian validation of the Dyadic Coping Inventory-Sexual Minority Stress (DCI-SMS) scale.

Lesbian, gay, bisexual, and transgender individuals (hereafter people with minoritized sexual orientation and/or gender identities) have limited legal rights and access to resources because of their marginalized status in society. These limitations are associated with notable health disparities and increase experiences of minority stress. For those in a romantic relationship, being able to communicate and cope with one's partner-dyadic coping-can help buffer stress' deleterious effects on well-being. Given the promise of understanding how dyadic coping can mitigate experiences of sexual minority stress, the Dyadic Coping Inventory-Sexual Minority Stress (DCI-SMS) was recently created and validated with those living in the United States to assess how partners cope with sexual minority stress. Answering a global call to expand psychological science beyond a U.S. centric perspective, the purpose of this study was to validate the DCI-SMS in German and Italian using samples from Austria, Germany, Switzerland, and Italy, respectively. Confirmatory factor analysis results, along with tests of convergent and discriminant validity, and measurement invariance, suggest that the DCI-SMS is a valid measure of stress communication and dyadic coping behaviors for those in a same-gender relationship in the countries sampled. Important future directions include examining its efficacy in other countries, such as those with more adverse sociopolitical climates for people with minoritized sexual orientation and/or gender identities in a same-gender relationship. Limitations and future directions for research and clinical practice are presented. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The evolution of microstructure and micro-texture in a metastable Fe45Co35Cr10V10 medium-entropy alloy subjected to cold rolling

Microstructure and micro-texture evolution in a Fe45Co35Cr10V10 medium-entropy alloy under 10‐–88% cold rolling was investigated by electron backscattering diffraction. The variant graph method reconstructed parent γ grain orientations at 20, 30 and 40% thickness reduction to determine the operative orientation relationships (ORs) with the child ε and α′-martensite phases and to study variant selection. The parent γ phase accommodates deformation by faulting, slip, shear banding and martensitic phase transformation via the γ→ε→α′and γ→α′pathways. The ε and α′ -martensite variant selection occurs within individual parent γ grains but not in the bulk microstructure. Variant pairing in α′-martensite shifts from a preference for the same crystallographic packet group to the same Bain group with increasing thickness reduction.The development of the Brass-type micro-texture in the parent γ phase beyond 40% thickness reduction is attributed to Cuγ and Sγ orientations transforming to ε and α′-martensite, along with shear banding. The micro-texture of ε-martensite records maximum intensities for ∼011¯537¯42ε and ∼112¯61¯1¯21ε on the hkil-fibre and originating from ∼Cuγ and Sγ via the Shoji-Nishiyama OR. The α′-martensite micro-texture is characterised by the αα′, γα′ and βα′ fibres. The βα′ -fibre forms between 20% and 60% thickness reduction and rotates towards stable orientations along the αα′-fibre at higher thickness reductions. Modelling shows that orientations along the βα′ and γα′ - fibres stem from ∼Brγ and ∼Sγ and those along the αα′-fibre originate from Gγ, Brγ, Cuγ, and Sγ.

Relative alignment between gas structures and magnetic field in Orion A at different scales using different molecular gas tracers

Context. Magnetic fields can play a crucial role in high-mass star formation. Nonetheless, the significance of magnetic fields at various scales and their relationship with gas structures have been largely overlooked. Aims. Our goal is to examine the relationship between the magnetic field and molecular gas structures within the Orion A giant molecular cloud at different scales and density regimes. Methods. We assessed the gas intensity structures and column densities in Orion A using 12CO, 13CO, and C18O from Nobeyama observations. By comparing Nobeyama observations with Planck polarization observations on large scales (~0.6 pc) and JCMT polarization observations on small scales (~0.04 pc), we investigate how the role of magnetic fields changes with scale and density. Results. We find a similar trend from parallel to perpendicular alignment with increasing column density in Orion A at both large and small spatial scales. In addition, when changing from low-density to high-density tracers, the relative orientation preference changes from random to perpendicular. The self-similar results at different scales indicate that magnetic fields are dynamically important in both cloud formation and filament formation. However, magnetic field properties at small scales are relative complicated, and the interplay between magnetic field and star-forming activity needs to be discussed case by case.

3D octopus kinematics of complex postures: Translation to long, thin, soft devices and their potential for clinical use.

Octopuses are capable of complex arm movements. Unfortunately, experimental barriers and lack of a robust analysis method made it difficult to quantify the three-dimensional (3D) kinematics of soft, flexible bodies, such as the octopus arm. This information is not only crucial for understanding the posture of the animal's arm but also for the development of similarly designed soft, flexible devices. The primary goal of this work was to create a method to comprehensively quantify complex, 3D postures of octopus (Octopus Bimaculoides) arms in a manner that is conducive and translatable to octopus arm-inspired devices for health monitoring and rehabilitation. In this study, 3D underwater motion capture was used to collect kinematic data on both live octopuses and disembodied arms that still had neural activity. A new method was developed to define how arm curvature and regional segments were oriented relative to each other in 3D. This included identification of the bend within a segment along with the computation of the relative orientation between segments, thus permitting the complete quantification of complex arm motions. By comparing vector-based and radius of curvature-based approaches to magnitude of curvature, it was clear that the vector-based approach was less dependent on the length of a segment and that its reported ranges of motion were translatable for outcome measures associated with clinical use. The new approach for the relative orientation of each segment of the octopus arm resulted in the capability of describing the octopus arm in many unique postures, such as straight, simple bending, and complex bending as it utilized the three rotational angles. This method and its application to octopus arms will yield new information that can be used to better communicate and track not only octopus arm movements but in the development of complex, segmented, soft-bodied devices that can be used in health monitoring and rehabilitation.

Enhanced tensile performance of ternary Fe-Ni-Ti peri-eutectic alloy through directional solidification associated with thermal processing

The microstructural evolution and tensile performance of ternary Fe66.5Ni17.6Ti15.9 peri-eutectic alloy were studied by synergetic modulation of directional solidification and thermal processing technique. The alloy after directional solidification consisted of the vertically growing α-Fe dendrites plus interdendritic γ-Fe(Ni) + Fe2Ti peri-eutectic. The in suit thermal processing promoted the precipitation transition of the α-Fe dendrites, and the lamellar Fe2Ti precipitate was formed along the α-Fe grain boundaries with different orientation relationships. Compared to the conventional solidification, the synergetic modulation not only reduced the transverse grain boundaries and hindered the crack propagation, but also introduced the second phase strengthening and impeded the dislocation movement in the α-Fe dendrites. Eventually, the tensile strength and Young’s modulus of this peri-eutectic alloy were enhanced by 253 % and 72 %.

Insight into the interfacial microstructure and chemistry of hot isostatically pressed AA6061-AA6061 bonds for U-10Mo fuel cladding application

Hot isostatic pressing (HIP) is performed on AA6061-AA6061 plates for U-10Mo monolithic fuel cladding application and this process allows us to bond multiple plates and large surface areas in a single run. In the current work, we HIP'd several plates of AA6061 with different HIP can dimensions at 560 °C and 103 MPa for 90 min to gain insight into the interfacial microstructure, chemistry and eventually bond strength. Interfacial microstructure characterizations were performed using scanning electron microscopy (SEM) combined with electron backscatter diffraction (EBSD) in conjunction with Transmission electron microscopy (TEM) to quantify precipitate fractions and study recrystallization, grain growth, and orientation relationships across the interface. Microstructural analyses revealed the precipitation of a large fraction of Mg2Si particles and a ∼50 nm thick Al-Mg oxide layer at the interface. Further TEM analysis confirmed that the oxide layer was not continuous, and Mg2Al2O5 oxide particles with an average size of 18 nm were present in the oxide layer. The bond strength of HIP-processed samples was correlated with peel testing and the bond strength was determined to be a direct function of the Mg2Si particle size at the interface. Finite element modeling analysis was performed to study the HIP can cooldown rate after HIP processing and was correlated with the interface precipitation.

Virtual photon exchange vs electron transfer in interparticle Coulombic electron capture.

We have investigated Interparticle Coulombic Electron Capture (ICEC) using an abinitio approach for two systems, H+ + H2O and H + H2O+. In this work, we have determined the contribution of virtual photon exchange and electron transfer to the total ICEC cross section as a function of the distance between the charged and neutral particles. Furthermore, we have shown that the relative orientation of the electron acceptor and neighbor systems affects the magnitude of the ICEC cross sections by at least two orders at relatively small distances. This geometry dependence, present even for distances as large as 10 a0, is due to the electron transfer contribution. The relative magnitude of each contribution to ICEC seems to depend on the system studied. By replacing the projectile electron with a positron, we have confirmed that electron transfer also takes place in positron collisions and that the charge of the projectile has a noticeable effect on the process, particularly at low scattering energies.

Future organizational resilience capability structure: a systematic review, trend and future research directions

Purpose The purpose of this paper is to systematically review the resilience literature to integrate the fragmented views and provide a more comprehensive understanding. This study aims to fill the gaps in the literature by discussing scientific contributions and highlighting the main issues in previous research findings regarding the definitions, dimensions and concepts that make up organizational resilience. This research highlights organizational resilience from a capabilities perspective. Design/methodology/approach This paper uses the systematic literature review method by searching all previous studies studying organizational resilience from 2014 to 2023. In total, there are 28 articles reviewed from the Scopus database. Findings This study found that resilience is a complex concept and has many definitions and dimensions. This study also conceptualizes organizational capability with a pyramid, which illustrates the basic framework of the six stages of the resilience process and hierarchically forms organizational resilience. Research limitations/implications First, the keyword search strings on the repository database are currently limited to a few keywords. Need to broaden the range of keywords so as to produce a more comprehensive review. Second, the exclusion of books, book chapters and conference papers limits research findings and results. These sources are likely to enrich resilience development from various perspectives. Even though Scopus is the largest repository database, the research findings are not yet fully generalizable. Future researchers can add data from WoS, Ebsco or other databases. Literature obtained from various databases that can provide broader results. Practical implications The practical implications of this study are to provide a basis for managers in making decisions for organizational sustainability. Managers can consider each stage in the resilience capability pyramid as a reference for making strategic plans and relational orientation toward organizational members. Originality/value This research provides a hierarchical perspective on organizational resilience capabilities. For academics and practitioners, this study provides a critical and comprehensive systematization of the limited academic literature on resilience. This study also offers opportunities for further research to overcome the limitations of empirical testing of resilience capability construction using various theories and methodologies.

Evaluation of the Parkinson's Remote Interactive Monitoring System in a Clinical Setting: Usability Study.

The fastest-growing neurological disorder is Parkinson disease (PD), a progressive neurodegenerative disease that affects 10 million people worldwide. PD is typically treated with levodopa, an oral pill taken to increase dopamine levels, and other dopaminergic agonists. As the disease advances, the efficacy of the drug diminishes, necessitating adjustments in treatment dosage according to the patient's symptoms and disease progression. Therefore, remote monitoring systems that can provide more detailed and accurate information on a patient's condition regularly are a valuable tool for clinicians and patients to manage their medication. The Parkinson's Remote Interactive Monitoring System (PRIMS), developed by PragmaClin Research Inc, was designed on the premise that it will be an easy-to-use digital system that can accurately capture motor and nonmotor symptoms of PD remotely. We performed a usability evaluation in a simulated clinical environment to assess the ease of use of the PRIMS and determine whether the product offers suitable functionality for users in a clinical setting. Participants were recruited from a user sign-up web-based database owned by PragmaClin Research Inc. A total of 11 participants were included in the study based on the following criteria: (1) being diagnosed with PD and (2) not being diagnosed with dementia or any other comorbidities that would make it difficult to complete the PRIMS assessment safely and independently. Patient users completed a questionnaire that is based on the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale. Interviews and field notes were analyzed for underlying themes and topics. In total, 11 people with PD participated in the study (female individuals: n=5, 45%; male individuals: n=6, 55%; age: mean 66.7, SD 7.77 years). Thematic analysis of the observer's notes revealed 6 central usability issues associated with the PRIMS. These were the following: (1) the automated voice prompts are confusing, (2) the small camera is problematic, (3) the motor test exhibits excessive sensitivity to the participant's orientation and position in relation to the cameras, (4) the system poses mobility challenges, (5) navigating the system is difficult, and (6) the motor test exhibits inconsistencies and technical issues. Thematic analysis of qualitative interview responses revealed four central themes associated with participants' perspectives and opinions on the PRIMS, which were (1) admiration of purpose, (2) excessive system sensitivity, (3) video instructions preferred, and (4) written instructions disliked. The average system usability score was calculated to be 69.2 (SD 4.92), which failed to meet the acceptable system usability score of 70. Although multiple areas of improvement were identified, most of the participants showed an affinity for the overarching objective of the PRIMS. This feedback is being used to upgrade the current PRIMS so that it aligns more with patients' needs.

Interaction Rules Supporting Effective Flocking Behavior.

Several simulation models have demonstrated how flocking behavior emerges from the interaction among individuals that react to the relative orientation of their neighbors based on simple rules. However, the precise nature of these rules and the relationship between the characteristics of the rules and the efficacy of the resulting collective behavior are unknown. In this article, we analyze the effect of the strength with which individuals react to the orientation of neighbors located in different sectors of their visual fields and the benefit that could be obtained by using control rules that are more elaborate than those normally used. Our results demonstrate that considering only neighbors located on the frontal side of the visual field permits an increase in the aggregation level of the swarm. Using more complex rules and/or additional sensory information does not lead to better performance.

Weak and strong chirality-anomaly-manipulations in a superconducting Weyl semimetal sandwich structure

We investigate the quantum interference of the electron–hole conversions from the two interfaces in a Weyl semimetal (WSM)-based hybrid structure, in which a superconducting WSM is sandwiched in between two normal ones. The quantum interference is characterized by the chirality-anomaly-manipulation (CAM). It is found that only low energy is in favor for s-wave BCS pairing states. The Andreev reflection (AR) chirality blockade can be tuned by the stagger angle α for the relative orientation of paired Weyl points, accompanied by an AR bipolar chirality diode. Thus, a strong CAM is indicated for the electron–hole conversion. However, the Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) pairing states have no energy preference, with the weak and strong CAMs being near and far away from the zero energy, respectively. More interestingly, a perfect AR with the normal reflection suppressed thoroughly can be obtained at any α as a result of the FFLO paring with the same chirality. In addition, the conductance or noise power, which incorporates the contributions of the two paired Weyl nodes, not only, in turn, embodies the respective features of their contributions but also can be experimentally measured to discern between the BCS and FFLO paring states.

Atomic-scale investigation on the evolution of T1 precipitates in an aged Al-Cu-Li-Mg-Ag alloy

The T1 (Al2CuLi) phase is one of the most effective strengthening nanoscale-precipitate in Al-Cu alloys with Li. However, its formation and evolution still need to be further clarified during aging due to the complex precipitation sequences. Here, a detailed investigation has been carried out on the atomic structural evolution of T1 precipitate in an aged Al-Cu-Li-Mg-Ag alloy using state-of-the-art Cs-corrected high-angle annular dark field (HAADF)- coupled with integrated differential phase contrast (iDPC)-scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDXS) techniques. An intermediate T1’ phase between T1p and T1 phase, with a crystal structure and orientation relationship consistent with T1, but exhibiting different atomic occupancy and chemical composition was found. We observed the atomic structural transformation from T1p to T1’ phase (fcc→hcp), involving only 1/12<112>Al shear component. DFT calculation results validated our proposed structural models and the precipitation sequence. Besides, the distributions of minor solute elements (Ag, Mg, and Zn) in the precipitates exhibited significant differences. These findings may contribute to a further understanding of the nucleation mechanism of T1 precipitate.

2‐ and 3‐Fluorocyclobutane Building Blocks for Organic and Medicinal Chemistry

Multigram synthesis of 3‐fluorinated cyclobutane building blocks has been disclosed. The proposed synthetic schemes were based on the nucleophilic fluorination and eventually led to 3‐fluorocyclocutanecarboxylic acid as a key target compound and intermediate. Further functional group transformations provided monofluorinated cyclobutane‐derived alcohols, amines, bromides, thiols, sulfonyl chlorides, etc. Furthermore, the synthesis of diastereopure cis‐ and trans‐isomeric 2‐ and 3‐fluorocyclobutane­carboxylic acids and amines was also performed. In both cases, diastereomer separation was used to obtain pure stereoisomers. The effect of the fluorine position and relative spatial orientation on the physicochemical properties of the corresponding monoflurinated derivatives was studied by measurements of pKa and logP values.

Effect of Primer and Fibre Orientation on Softwood–Hardwood Bonding

Softwood is widely employed in construction and faces high demand. Australia is grappling with substantial timber scarcity, specifically related to radiata pine, which is the dominant structural timber in the construction sector. However, Australia has a significant hardwood population, which can be utilized to reduce the high demand for radiata pine. This paper aims to investigate the bond properties of both Australian softwood (radiata pine) and hardwood (shining gum). It also discusses the potential to combine softwood and hardwood in glue or cross-laminated timber by evaluating the bond properties of the radiata pine–shining gum interface. For hardwood, the effect of primer is also investigated to determine its efficacy in improving failure mode, bond strength, and stiffness. Lastly, both glulam and cross-laminated timber bonding scenarios are simulated for bond testing by examining the effect of relative fibre orientation on the bond properties of the aforementioned species individually and in combination. Instead of conventional block shear testing, which is predominantly used for same-species bond testing, push-out testing is adopted in this study. However, a comparison with block shear testing is also made in this article. The results indicated that the use of primer on hardwood reduced the inconsistencies in the bond properties and improved wood-side failure rates. It was also concluded that the effect of fibre orientation in a CLT scenario with combined hardwood and softwood failure modes can vary significantly, which leads to a higher standard deviation in the results. Nevertheless, this study outlines the challenges and opportunities for producing hardwood–softwood hybrid glue or cross-laminated timber.

Training-induced changes in population receptive field properties in visual cortex: Impact of eccentric vision training on population receptive field properties and the crowding effect.

This study aimed to investigate the impact of eccentric-vision training on population receptive field (pRF) estimates to provide insights into brain plasticity processes driven by practice. Fifteen participants underwent functional magnetic resonance imaging (fMRI) measurements before and after behavioral training on a visual crowding task, where the relative orientation of the opening (gap position: up/down, left/right) in a Landolt C optotype had to be discriminated in the presence of flanking ring stimuli. Drifting checkerboard bar stimuli were used for pRF size estimation in multiple regions of interest (ROIs): dorsal-V1 (dV1), dorsal-V2 (dV2), ventral-V1 (vV1), and ventral-V2 (vV2), including the visual cortex region corresponding to the trained retinal location. pRF estimates in V1 and V2 were obtained along eccentricities from 0.5° to 9°. Statistical analyses revealed a significant decrease of the crowding anisotropy index (p = 0.009) after training, indicating improvement on crowding task performance following training. Notably, pRF sizes at and near the trained location decreased significantly (p = 0.005). Dorsal and ventral V2 exhibited significant pRF size reductions, especially at eccentricities where the training stimuli were presented (p < 0.001). In contrast, no significant changes in pRF estimates were found in either vV1 (p = 0.181) or dV1 (p = 0.055) voxels. These findings suggest that practice on a crowding task can lead to a reduction of pRF sizes in trained visual cortex, particularly in V2, highlighting the plasticity and adaptability of the adult visual system induced by prolonged training.

Microstructures and mechanical properties of Ti-55511 alloy subjected to rolling in the α+β dual-phase region

In this study, dual-phase region rolling was conducted on a Ti-55511 alloy with different initial rolling reductions in the single-phase region. The mechanical properties and microstructural characteristics of the alloy with different deformation conditions were investigated. Microstructure observations show the formation of a heterogeneous structure with a gradient size distribution of the α phase at the recrystallized grain boundaries, induced by the non-uniform stress distribution. The α phase and the β matrix exhibit the Burgers orientation relationship in the recrystallized region with the gradient structure. However, in the unrecrystallized region of the partially recrystallized specimens and in the grain interiors of the fully recrystallized specimens, the α phase and the β phase exhibit Pitsch-Schrader orientation relationship (P–S OR). A large number of the nano-sized α" martensite bands were observed after the dual-phase region rolling. These bands originated from the α/β interfaces and grew towards the interiors of the α phase. As the deformation increased, these nano-bands underwent a transformation into the {10 1‾ 1}α deformation twins, resulting in the fragmentation of the α phase. Mechanical testing results show that the mechanical properties of the alloy can be improved by the dislocation strengthening, the generation of profuse α phase and other microstructures including the heterogeneous distribution of the α phase, the nano-sized α" martensite and the {10 1‾ 1}α deformation twins.