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Realization of a one-dimensional topological insulator in ultrathin germanene nanoribbons
Get PDFRealizing a one-dimensional (1D) topological insulator and identifying the lower-dimensional limit of two-dimensional (2D) behavior are crucial steps toward developing high-density quantum state networks, advancing topological quantum computing, and exploring dimensionality effects in topological materials. Although 2D topological insulators have been experimentally realized, their lower dimensional limit and 1D counterparts remain elusive. Here, we fabricated and characterized arrays of zigzag-terminated germanene nanoribbons, a 2D topological insulator with a large topological bulk gap. The electronic properties of these nanoribbons strongly depend on their width, with topological edge states persisting down to a critical width (∼2 nm), defining the limit of 2D topology. Below this threshold, contrary to the tenfold way classification, we observe zero-dimensional (0D) states localized at the ends of the ultrathin nanoribbons. These end states, topologically protected by time-reversal and mirror symmetries, indicate the realization of a 1D topological insulator with strong spin-orbit coupling. Our findings establish germanene nanoribbons as a platform for investigating 1D topology and dimensionality effects in topological materials.</p
Multirotor UAV—A Multidisciplinary Platform for Teaching Mechatronics Engineering
Get PDFThis paper provides a comprehensive guide for educators on how multirotor UAV platforms can be utilized to achieve various learning outcomes in undergraduate mechatronics education. This study is based on a PX4 ecosystem combined with the MATLAB Simulink programming environment, covering both hardware and software aspects to support engineering education. The paper explains (i) which learning outcomes can be obtained, (ii) how mathematical models can be derived and implemented in simulation software, (iii) which hardware components are essential, their approximate costs, and possible upgrades based on available budgets, and (iv) which experiments students can perform using the UAV platform. A proposed educational prototype integrates airframe parts produced using additive manufacturing technologies with standard multirotor components. Additionally, a series of experiments were designed, including extensive testing of the multirotor control module. Three learning outcomes related to UAV hardware were incorporated into the engineering curriculum, while two software-related outcomes were addressed through student workshops. Future plans include the implementation of multiple UAV platforms in the educational process to further enhance learning outcomes.</p
Sustainability in marketing::A review using multiple correspondence analysis
Get PDFThis study examines the state of sustainability in leading marketing research and proposes a bottom-up framework that involves business managers, consumers and the environment at different levels. A qualitative approach involving multiple correspondence analysis is used to examine the status of sustainability in marketing, and a solution-oriented framework based on a bottom-up approach is designed. Three dimensions are determined to be at the heart of the consumer–business–society relationship: sustainable environmental awareness and responsibility, production and consumption practices, and intercompany and industrial collaborations. Based on these dimensions, a holistic framework is developed to address the conflicts between theory and practice toward sustainability values. This study refines the market-driven concept and guides scholars through our proposed path that unites marketing and sustainability. We also design a framework by incorporating social marketing elements into businesses to achieve sustainability. Ultimately, this study offers insights into consumer research, marketing management and sustainable business practices.</p
Toward real-time margin assessment in breast-conserving surgery with hyperspectral imaging
Get PDFMargin assessment in breast-conserving surgery (BSC) remains a critical challenge, with 20-25% of cases resulting in inadequate tumor resection, increasing the risk of local recurrence and the need for additional treatment. In this study, we evaluate the diagnostic performance of hyperspectral imaging (HSI) as a non-invasive technique for assessing resection margins in ex vivo lumpectomy specimens. A dataset of over 200 lumpectomy specimens was collected using two hyperspectral cameras, and a classification algorithm was developed to distinguish between healthy and tumor tissue within margins of 0 and 2 mm. The proposed approach achieved its highest diagnostic performance at a 0 mm margin, with a sensitivity of 92%, specificity of 78%, accuracy of 83%, Matthews correlation coefficient of 68%, and an area under the curve of 89%. The entire resection surface could be imaged and evaluated within 10 minutes, providing a rapid and non-invasive alternative to conventional margin assessment techniques. These findings represent a significant advancement toward real-time intraoperative margin assessment, highlighting the potential of HSI to enhance surgical precision and reduce re-excision rates in BCS.</p
Machine learning for semi-automated land parcel plotting
No full textThe Indonesian cadastral quality improvement process, established in 2018, faces huge challenges due to its huge land area, diverse natural and social conditions, and historical mapping practices. With 15 million land parcels yet to be plotted accurately, in this work we propose a solution based on machine learning to speed up the process of plotting parcels documented on old land certificates and maps. Our approach is a heuristic-driven geospatial data matching procedure that semi-automatically searches for possible locations for plotting land parcels. The heuristic aspect of the approach is its basis in the manual plotting method in use presently in Indonesia. We identified eight causes of unplotted parcels and for two of these causes we have implemented an optimization algorithm model defined over five geometric parcel attributes. The model is then optimized using the RCGA algorithm. The model performed with recall rates of 88.3% and 57% on test data and real data respectively, and precision rates of 98.8% and 91% also respectively for test data and real data. After the incorporation of text information in old cadastral maps, the recall value for real data improved to 91%
Influence of plant-based compounds on the structural stability of mucous boundary layers in tribological contact
Get PDFThis study presents a new methodology for understanding the molecular interactions of plant-based compounds on lubricating boundary layers in oral contacts. The methodology was used to investigate the impact of a plant protein (fava bean protein isolate) and a phenolic compound (tannic acid) on the structure and lubricating property of mucous boundary layers. Tribological experiments, coupled with quartz crystal microbalance with dissipation monitoring measurements and fluorescence microscopy imaging, were used to elucidate the mechanism of boundary film disruption and lubrication losses. It was found that even at concentrations up to 5 % w/v, fava bean proteins bind to mucins and hydrophobic polydimethylsiloxane (PDMS) surfaces, forming a hydrated, hydrophilic layer that sustains lubrication. Conversely, even at concentrations lower than 0.5 % w/v, tannic acid interacts strongly with mucins via hydrophobic interactions and/or hydrogen bonding, leading to protein aggregation, interrupting mucin binding onto PDMS, and increasing friction due to the disruption of the lubricating boundary layer. Fluorescent microscopy images revealed that the tannic acid-bovine submaxillary mucin interaction impairs the stability of the mucous boundary film, facilitating mucous protein detachment during a single sliding experiment of a PDMS probe. Results from these investigations provide critical insights into the molecular-level mechanisms influencing oral lubrication, particularly for the development of polyphenol-rich foods, and emphasize the importance of tribological assessment as a research tool in the development of plant-based protein alternatives.</p
Facet-Dependent Performance of Microstructured SrTiO<sub>3</sub> Particles in Photocatalytic Oxidation of Acetone
Get PDFPhotocatalysis is a promising technology for purification of indoor air by oxidation of volatile organic compounds. This study provides a comprehensive analysis of the adsorption and photo-oxidation of surface-adsorbed acetone on three SrTiO3 morphologies: cubes (for which exclusively {100} facets are exposed), {110}-truncated cubes, and {100}-truncated rhombic dodecahedrons, respectively, all prepared by hydrothermal synthesis. In situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy shows that cubic crystals contain a high quantity of surface –OH groups, enabling significant quantities of adsorbed acetone in the form of η1-enolate when exposed to gas phase acetone. Contrary, {110} facets exhibit fewer surface –OH groups, resulting in relatively small quantities of adsorbed η1-acetone, without observable quantities of enolate. Interestingly, acetate and formate signatures appear in the spectra of cubic, surface η1-enolate containing, SrTiO3 upon illumination, while besides acetate and formate, the formation of (surface) formaldehyde was observed on truncated cubes, and dodecahedrons, by conversion of adsorbed η1-acetone. Time-Resolved Photoluminescence studies demonstrate that the lifetimes of photogenerated charge carriers vary with crystal morphology. The shortest carrier lifetime (τ1 = 33 ± 0.1 ps) was observed in {110}-truncated cube SrTiO3, likely due to a relatively strong built-in electric field promoting electron transport to {100} facets and hole transport to {110} facets. The second lifetime (τ2 = 259 ± 1 ps) was also the shortest for this morphology, possibly due to a higher amount of surface trap states. Our results demonstrate that SrTiO3 crystal morphology can be tuned to optimize performance in photocatalytic oxidation.</p
The lithosphere-asthenosphere system beneath the North Atlantic and surroundings:Results from multi-observable probabilistic inversions
Get PDFThe North Atlantic region is a complex geodynamic setting that comprises multiple continental blocks, sedimentary basins, mid-ocean ridge systems and prominent hotspots. Recent geophysical surveys of the near-surface have enhanced our understanding of crustal elements and the shallow lithosphere. However, our knowledge of the deep lithospheric structure and the physical state and dynamics of the upper mantle is still limited. Here, we exploit the combined sensitivity of surface-wave data, geoid anomalies, absolute topography and surface heat flow to obtain full thermochemical models of the region from the surface down to 350 km. We jointly invert these data sets using a simulation-based, multi-observable probabilistic framework. We validate our results with independent thermobarometric and chemical information from mantle xenoliths and test the effects of using different seismic models on the inversion results. Our model reveals an intricate sublithospheric flow system, driven by the interaction of deep upwellings with the highly irregular lithospheric structure. We corroborate that the main thermal anomaly in the sublithospheric mantle shows a tilted geometry, moving toward Greenland with depth. We reveal that this large-scale anomaly transition into a more complex pattern once it reaches depths of (Formula presented.) 150 km beneath the North Atlantic. Small-scale downwellings originate from the margins of continental domains, resulting in a complex circulation pattern that limits the radial spread of the deep upwellings and preferentially focuses them within regions of thin lithosphere along a N–S direction. Distinct compositional anomalies in the Greenland lithosphere delineate the North Atlantic Craton, the Nagssugtoqidian mobile belt, and the covered remnants of the Disko Craton. In continental Europe, the East European Craton shows clear indications of depletion in incompatible elements, with the Kola-Karelian cratonic region showing the highest levels of depletion. Our model serves as a base to make interpretations on the enigmatic paleotectonic history of the North-Atlantic region.</p
Inverse solving the Schrödinger equation for precision alignment of a microcavity
Get PDFIn paraxial approximation, the electromagnetic eigenmodes inside an optical microresonator can be derived from a Schrödinger-type eigenvalue problem. In this framework, tilting the cavity mirrors introduces a linear term to the potential energy of the system. In our paper, we apply solution strategies for inverse problems to precisely determine and control the relative orientation of two mirrors forming an optical microcavity. Our approach employs the inversion of the Schrödinger equation to reconstruct the effective potential landscape, and thus mirror tilts, from observed mode patterns. We investigate regularization techniques to address the ill-posed nature of inverse problems and to improve the stability of solutions. Our method consistently achieves an angle resolution of order 100 nanoradians per measurement. We consider our method applicable to a wide variety of optical resonators and driving schemes.</p