Kaikki aineistot
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Abstract In this paper, the edgewise and flatwise compressive behaviour of an innovative sandwich panel, mainly developed for quick assembly of post-disaster housing as well as load bearing panels for pre-fabricated modular construction and semi-permanent buildings, is investigated experimentally and by finite element modelling. The panel is composed of two 3-D high-density polyethylene (HDPE) sheets as the skins, filled with high-density Polyurethane (PU) foam as the core. HDPE sheets manufactured with a studded surface considerably enhance the stress distribution and buckling performance of the sandwich panel. Material characterisation tests and flatwise compression and edgewise compression experiments were performed in accordance with ASTM standards to evaluate the compressive strength and the load-carrying behaviour of the sandwich panels. A finite element analysis and validation were also conducted to model the compressive behaviour of sandwich structures. Results demonstrate that the developed sandwich panel exhibits very good compressive performance
Abstract In this paper, an innovative and efficient sandwich panel is proposed for the structural walls for quickly assembled post-disaster housing, as well as load bearing panels for pre-fabricated modular construction and semi-permanent buildings. This study focuses on the flexural and shear behavior of the innovative sandwich panels, which is composed of two 3-D high density polyethylene (HDPE) skins, and high-density Polyurethane (PU) foam core. An experimental study was carried out to validate the effectiveness of this panel for increasing the ultimate bending strength. A series of experimental tests were performed on medium-scale specimens to characterize their core shear behavior. Then, some supplementary tests were run to determine the panels’ flexural and shear stiffness. The numerical and experimental investigations show that the 3-D-HDPE sheets, manufactured with a studded surface; considerably enhance the pull-out and delamination strength. Good agreement has been observed between the numerical and experimental tests.
We demonstrate controlled pumping of Cooper pairs down to the level of a single pair per cycle, using an rf-driven Cooper-pair sluice. We also investigate the breakdown of the adiabatic dynamics in two different ways. By transferring many Cooper pairs at a time, we observe a crossover between pure Cooper-pair and mixed Cooper-pair-quasiparticle transport. By tuning the Josephson coupling that governs Cooper-pair tunneling, we characterize Landau-Zener transitions in our device. Our data are quantitatively accounted for by a simple model including decoherence effects.
We demonstrate controlled pumping of Cooper pairs down to the level of a single pair per cycle, using an rf-driven Cooper-pair sluice. We also investigate the breakdown of the adiabatic dynamics in two different ways. By transferring many Cooper pairs at a time, we observe a crossover between pure Cooper-pair and mixed Cooper-pair-quasiparticle transport. By tuning the Josephson coupling that governs Cooper-pair tunneling, we characterize Landau-Zener transitions in our device. Our data are quantitatively accounted for by a simple model including decoherence effects.
Tensile tests in air with hydrogen pre-charged smooth specimens and slow strain rate tests with smooth and notched specimens in hydrogenated high-temperature water (HTW) at elevated temperatures (250−288 °C) on low-alloy reactor pressure vessel (RPV) steels revealed a softening in strength and a pronounced reduction in ductility, where the magnitude of hydrogen embrittlement (HE) increased with the dynamic strain ageing (DSA) susceptibility of the RPV steels. In hydrogen pre-charged specimens and in hydrogenated HTW, shear dominated transgranular fracture by microvoid coalescence with increasing amounts of macrovoids, quasi-cleavage regions and secondary cracking were observed. Thermal desorption spectroscopy showed an increase in the concentration of trapped hydrogen in high binding energy traps (vacancies & voids) induced by straining in DSA regime. The observed hydrogen effects on fracture behaviour is a consequence of plasticity localization resulting from the interaction between DSA and hydrogen. HESIV and HELP are the dominant HE mechanisms.
Abstract Introduction: While young adults with chronic low back pain (CLBP) exhibit impaired lumbar proprioception, it remains unclear if the same phenomenon is observed in middle-aged adults with CLBP. Objectives: This study aimed to investigate whether young or middle-aged adults with CLBP displayed different proprioception ability as compared to age-matched asymptomatic controls. Methods: Sixty-four young adults with [median age:34 [interquartile range (IQR): 29–37] years] and without [median age:29 (IQR; 23–34) years] CLBP, and 87 middle-aged adults with [median age:53 (IQR: 49–58) years] and without [median age: 54 (IQR: 45–64) years] CLBP underwent postural sway tests on a force-plate with (unstable surface) and without a foam (stable surface), while bilateral L5/S1 multifidi and triceps-surae were vibrated separately. An individual’s proprioception reweighting ability was estimated by relative proprioceptive reweighting (RPW). Higher RPW values indicate less reliance on lumbar multifidus proprioceptive signals for balance. Participants also underwent lumbar repositioning tests in sitting to determine repositioning errors in reproducing target lumbar flexion/extension positions. Results: Young adults with CLBP demonstrated significantly higher median RPW values than age-matched asymptomatic controls for maintaining standing balance [stable surface: CLBP: 0.9 (IQR: 0.7–0.9), asymptomatic: 0.7 (IQR: 0.6–0.8), p < 0.05; unstable surface: CLBP: 0.6 (IQR: 0.4–0.8), asymptomatic: 0.5 (IQR: 0.3–0.7), p < 0.05]. No significant differences in repositioning error were noted between young or middle-aged adults with and without CLBP (p > 0.05). RPW values were unrelated to repositioning errors in all groups (p > 0.05). Conclusion: Young adults with CLBP, and middle-aged adults with and without CLBP had inferior proprioceptive reweighting capability. This finding may indicate potential age-related deterioration in central and peripheral processing of lumbar proprioceptive signals. Future studies should use advanced imaging and/or electroencephalogram to determine mechanisms underlying changes in proprioceptive reweighting in middle-aged adults.
Abstract Introduction: Lumbar multifidus muscle (LMM) dysfunction is thought to be related to pain and/or disability in people with chronic low back pain (CLBP). Although psychosocial factors play a major role in pain/disability, they are seldom considered as confounders in analyzing the association between LMM and CLBP. Objectives: This study aimed to determine: (1) differences in psychological factors, insomnia, and LMM characteristics between people with and without CLBP; (2) associations between psychological factors, insomnia, or LMM characteristics and low back pain (LBP) intensity or LBP-related disability in people with CLBP; and (3) whether LMM characteristics are related to LBP symptoms in people with CLBP after considering confounders. Methods: Seventy-eight volunteers with CLBP and 73 without CLBP provided sociodemographic information, filled the 11-point numeric pain rating scale and Roland-Morris disability questionnaire (RMDQ). They completed the Hospital Anxiety and Depression Scale (HADS), Pain Catastrophizing Scale (PCS), Fear Avoidance Belief Questionnaire (FAB), and Insomnia Severity Index Scale (ISI). Resting and contracted thickness of LMM at L4-S1 levels were measured from brightness-mode ultrasound images. Percent thickness changes of LMM at L4-S1 levels during contraction were calculated. Resting LMM stiffness at L4-S1 was measured by shear wave elastography. Associations among LMM, psychosocial or insomnia parameters and clinical outcomes were analyzed by univariate and multivariate analyses. Results: People with CLBP demonstrated significantly higher LBP-intensity, RMDQ, HADS, FAB, PCS, and ISI scores than asymptomatic controls (p < 0.05). The former also had significantly smaller percent thickness changes of LMM at L4/L5 during contraction. LBP-intensity was positively related to scores of PCS-total, PCS-helplessness, FAB-total, FAB-work, and ISI in people with CLBP (p < 0.05). RMDQ scores were positively associated with the scores of HADS-total, HADS-depression, PCS-total, FAB-total, FAB-physical activity, PCS-helplessness, and ISI in people with CLBP (p < 0.05). FAB-work and ISI scores together explained 24% of LBP-intensity. FAB-total scores alone explained 34% of variance of LBP-related disability in people with CLBP. Conclusion: More fear-avoidance belief or insomnia is related to greater LBP-intensity and/or LBP-related disability in people with CLBP. Although people with CLBP were thought to have aberrant LMM morphometry/function, no LMM characteristics were related to LBP-intensity or LBP-related disability after considering other confounders.
Three possible twinning modes, Type I, Type II, and compound, as well as corresponding twin boundaries in 2H martensite of Cu69.4Ni3.4Al27.2 single crystal, were studied by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The results are discussed with regard to the sharply different twinning stress or twin-boundary mobility. In self-accommodated martensite, all three modes not only coexist but are crystallographically coupled. The compound twin boundary is a coherent coplanar mirror plane with the smallest twinning shear. The Type II twin boundary is also a coherent strain-free interface. The high index rational approximation of Type II twin boundary was determined by trace analysis with the help of stereographic projection. The approximation is in good agreement with irrational indices calculated from elastic continuum. The Type I boundary is the most complex interface associated with high stress and high density of stacking faults inside the twin bands. Using HRTEM, twodifferent stressed boundaries of Type I were confirmed. The intrinsic twinning mode in Cu-Ni-Al alloy is the compound twinning. In compression, the Type II twinning is the major deformation twinning mode. During deformation the Type I twins are eliminated, leaving Type II twinning bands with compound twins. The observed differences between the atomic structure of different twin boundaries can contribute significantly to the sharp differences in twinning stress.
Abstract Copy-and-paste operations are the most popular features on computing devices such as desktop computers, smartphones and tablets. However, the copy-and-paste operations are not sufficiently addressed on the Augmented Reality (AR) smartglasses designated for real-time interaction with texts in physical environments. This paper proposes two system solutions, namely Granularity Scrolling (GS) and Two Ends (TE), for the copy-and-paste operations on AR smartglasses. By leveraging a thumb-size button on a touch-sensitive and pressure-sensitive surface, both the multi-step solutions can capture the target texts through indirect manipulation and subsequently enables the copy-and-paste operations. Based on the system solutions, we implemented an experimental prototype named Press-n-Paste (PnP). After the eight-session evaluation capturing 1,296 copy-and-paste operations, 18 participants with GS and TE achieve the peak performance of 17,574 ms and 13,951 ms per copy-and-paste operation, with 93.21% and 98.15% accuracy rates respectively, which are as good as the commercial solutions using direct manipulation on touchscreen devices. The user footprints also show that PnP has a distinctive feature of miniaturized interaction area within 12.65 mm * 14.48 mm. PnP not only proves the feasibility of copy-and-paste operations with the flexibility of various granularities on AR smartglasses, but also gives significant implications to the design space of pressure widgets as well as the input design on smart wearables.
Abstract In this study, sources of recharge and contamination in urban groundwater and in groundwater underneath a forest in the same aquifer were determined and compared. Data on hydro-chemical parameters and stable isotopes of water were collected in urban and forest springs in the Kharkiv region, Ukraine, over a period of 12 months. Groundwater transit time and precipitation contribution were calculated using hydrogeological data and stable isotopes of water to delineate groundwater recharge conditions. Hydro-chemical data, stable isotopes and emerging contaminants were used to trace anthropogenic groundwater recharge and approximate sewage and tap water contributions to the aquifer. The results indicated that each spring had unique isotopic signatures that could be explained by recharge conditions, groundwater residence time, and specific mixing patterns with sewage and water leaks. Elevated nitrate content, stable isotopes of nitrate, and the presence of emerging pollutants (mainly illicit drugs) in most of the urban springs confirmed mixing of urban groundwater with sewage leaks. These leaks amounted to up to 25% of total recharge and exhibited seasonal variations in some springs. Overall, the results show that urban groundwater receives variable seasonal contributions of anthropogenic components that increase the risk to the environment and human health, and reduce its usability for drinking water production. The multi-tracing approach presented can be useful for other cities worldwide that have similar problems of poor water management and inadequate sewage and water supply infrastructure.
Abstract Pulsating aurorae (PsA) are caused by the intermittent precipitations of magnetospheric electrons (energies of a few keV to a few tens of keV) through wave-particle interactions, thereby depositing most of their energy at altitudes ~ 100 km. However, the maximum energy of precipitated electrons and its impacts on the atmosphere are unknown. Herein, we report unique observations by the European Incoherent Scatter (EISCAT) radar showing electron precipitations ranging from a few hundred keV to a few MeV during a PsA associated with a weak geomagnetic storm. Simultaneously, the Arase spacecraft has observed intense whistler-mode chorus waves at the conjugate location along magnetic field lines. A computer simulation based on the EISCAT observations shows immediate catalytic ozone depletion at the mesospheric altitudes. Since PsA occurs frequently, often in daily basis, and extends its impact over large MLT areas, we anticipate that the PsA possesses a significant forcing to the mesospheric ozone chemistry in high latitudes through high energy electron precipitations. Therefore, the generation of PsA results in the depletion of mesospheric ozone through high-energy electron precipitations caused by whistler-mode chorus waves, which are similar to the well-known effect due to solar energetic protons triggered by solar flares.
Strain accumulation was studied by digital image correlation technique (DIC) during microstructurally small fatigue crack propagation in polycrystalline 18%Cr ferritic stainless steel. Load-controlled fatigue testing was performed with R-ratio of 0.1 and frequency 10 Hz. The maximum applied stress was well below the yield stress of the studied material. The effect of the observed strain field on crack growth rate variation is discussed. Fracture surfaces were studied by scanning electron microscopy (SEM) evidencing the connection between the mechanism of the fatigue crack growth, accumulated strain and crack growth rate. Detailed study of fracture surface morphology was carried out by atomic force microscopy (AFM). Results indicate two processes of material damage accumulation and failure during cyclic loading: 1) local shear strain zones form successively ahead of the crack tip, and 2) fatigue crack growth occurs by both single- and multiple-slip mechanisms. The place and intensity of shear strain localization zones vary during the crack growth that is related closely to the local variation of crack growth rate.
Abstract Enabling and empowering the diverse energy resources to have active yet efficient participation in the smart grid and energy market is an unrivaled challenge for the energy industry. This research expands the four dominant archetypes of business models in the energy and electricity market, creating a fifth archetype, the “blockchain marketplace”. The contributions of the study are to identify the extant electricity market designs and architectures as centralized and pseudo-decentralized while proposing a fully decentralized architecture enabled by the blockchain. The research contributes to the literature of smart grids and demand-side management and introduces the value configuration/architecture approach for the energy market and business model domains.
We study the interaction between a magnetic dipole mimicking the Gerasimovich magnetic anomaly on the lunar surface and the solar wind in a self-consistent 3-D quasi-neutral hybrid simulation where ions are modeled as particles and electrons as a charge-neutralizing fluid. Especially, we consider the origin of the recently observed electric potentials at lunar magnetic anomalies. An antimoonward Hall electric field forms in our simulation resulting in a potential difference of <300 V on the lunar surface, in which the value is similar to observations. Since the hybrid model assumes charge neutrality, our results suggest that the electric potentials at lunar magnetic anomalies can be formed by decoupling of ion and electron motion even without charge separation.
Abstract This study explores the links between climate change, consumer lifestyles, and legitimation strategies of sustainable firms. Our findings offer new insight into this under-researched area based on qualitative case studies of four Nordic firms operating in industrial and consumer contexts. We find that climate change consciousness is a major driver for all case firms’ sustainability-focused operations, but the dynamics differed. Achieving sociopolitical legitimacy emerges as an important factor for the case firms operating in the energy sector, especially as it connects to government incentives and regulative pressures. However, cognitive legitimacy is increasingly important for them also, and the firms are trying to connect to their consumers’ lifestyles as well. In turn, for the case firms operating in the consumer (clothing) industry, functionality and the use of products are highlighted even though cognitive legitimacy based on linking to their consumers’ lifestyle is visible. Finally, the findings reveal that despite the sustainable lifestyles are increasingly important and better recognized in firm strategies and practices, other practicalities of running the business successfully in a highly competitive marketplace are relevant. Building legitimacy in such a way that captures and justifies different approaches, therefore, emerges as the connecting factor between the changing consumer behavior and pro-environmental firm practices.
Abstract Real-time holographic video communications enable immersive experiences for next-generation video services in the future metaverse era. However, high-fidelity holographic videos require high bandwidth and significant computation resources, which exceed the transferring and computing capacity of 5G networks. This article reviews state-of-the-art holographic point cloud video transmission techniques and highlights the critical challenges of delivering such immersive services. We further implement a preliminary prototype of an AI-driven holographic video communication system and present critical experimental results to evaluate its performance. Finally, we identify future research directions and discuss potential solutions for providing real-time and high-quality holographic experiences.
Abstract In conventional cognitive radio networks, channels that are in use by opportunistic secondary users (SUs) can be recaptured by the network’s licensed primary users (PUs) at will, thus interrupting the connectivity of the former. To compensate for this, we propose here a semi-cogntive radio network (SCRN) paradigm where PUs are constrained to first use all free channels in the network before being allowed to capture channels that are currently in use by SUs. By imposing a monetary (or other) penalty to the network’s secondary spectrum owners when opportunistic channel use becomes excessive, this additional constraint only induces a slight drop in the PUs’ performance while offering significant benefits to the network’s SUs. In this paper, we provide a game-theoretic analysis of such systems and we derive both centralized and decentralized adaptive algorithms that allow the system control process to converge to a stable equilibrium state. Our numerical results show that, with the same channel efficiency, SCRNs provide increased profits to the primary network and significantly reduced interruption rates to the secondary network.
Abstract More than 60 percentage of fatal accidents while riding a bicycle is caused by elderly people over 65 years old. The main cause is the detection delay of approaching vehicle caused by the decrease of cognitive function due to aging. In this paper, we propose an approaching vehicle detection method using a smartphone aiming to support bicycle operation to prevent elderly people from fatal accidents while riding a bicycle vehicle. Among various sensors embedded in a smartphone, we focus on microphone as the most suitable sensor for detecting an approaching vehicle. We collected sound data in a real environment and created an approaching vehicle detection model by using machine learning. Finally, as a result of accuracy evaluation with 10-fold cross-validation, we confirmed that it can detect approaching vehicle with an average F-value of 97.4 [%].
Abstract Human phytanoyl-CoA dioxygenase domain-containing 1 (PHYHD1) is a 2-oxoglutarate (2OG)-dependent dioxygenase implicated in Alzheimer’s disease, some cancers, and immune cell functions. The substrate, kinetic and inhibitory properties, function and subcellular localization of PHYHD1 are unknown. We used recombinant expression and enzymatic, biochemical, biophysical, cellular and microscopic assays for their determination. The apparent Km values of PHYHD1 for 2OG, Fe2+ and O2 were 27, 6 and > 200 μm, respectively. PHYHD1 activity was tested in the presence of 2OG analogues, and it was found to be inhibited by succinate and fumarate but not R-2-hydroxyglutarate, whereas citrate acted as an allosteric activator. PHYHD1 bound mRNA, but its catalytic activity was inhibited upon interaction. PHYHD1 was found both in the nucleus and cytoplasm. Interactome analyses linked PHYHD1 to cell division and RNA metabolism, while phenotype analyses linked it to carbohydrate metabolism. Thus, PHYHD1 is a potential novel oxygen sensor regulated by mRNA and citrate.
We report p-type behavior for undoped GaN1-xSbx alloys with x ≥ 0.06 grown by molecular beam epitaxy at low temperatures (≤400 °C). Rapid thermal annealing of the GaN1-xSbx films at temperatures >400 °C is shown to generate hole concentrations greater than 1019 cm-3, an order of magnitude higher than typical p-type GaN achieved by Mg doping. The p-type conductivity is attributed to a large upward shift of the valence band edge resulting from the band anticrossing interaction between localized Sb levels and extended states of the host matrix.
Abstract It is well known that auroral patterns at the substorm recovery phase are characterized by diffuse or patch structures with intensity pulsation. According to satellite measurements and simulation studies, the precipitating electrons associated with these aurorae can reach or exceed energies of a few hundreds of keV through resonant wave‐particle interactions in the magnetosphere. However, because of difficulty of simultaneous measurements, the dependency of energetic electron precipitation (EEP) on auroral morphological changes in the mesoscale has not been investigated to date. In order to study this dependency, we have analyzed data from the European Incoherent Scatter (EISCAT) radar, the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) riometer, collocated cameras, ground‐based magnetometers, the Van Allen Probe satellites, Polar Operational Environmental Satellites (POES), and the Antarctic‐Arctic Radiation‐belt (Dynamic) Deposition‐VLF Atmospheric Research Konsortium (AARDDVARK). Here we undertake a detailed examination of two case studies. The selected two events suggest that the highest energy of EEP on those days occurred with auroral patch formation from postmidnight to dawn, coinciding with the substorm onset at local midnight. Measurements of the EISCAT radar showed ionization as low as 65 km altitude, corresponding to EEP with energies of about 500 keV.
The structural, chemical, and electronic properties of epitaxial graphene films grown by thermal decomposition of the Si-face of a semi-insulating 6H-SiC substrate in an argon environment are studied by Raman spectroscopy, X-ray photoelectron spectroscopy and angle-resolved photoemission. It was demonstrated the possibility of fabrication of the gas and biosensors that is based on grown graphene films. The gas sensors are sufficiently sensitive to NO2 at low concentrations. The biosensor operation was checked using an immunochemical system comprising fluorescein dye and monoclonal anti fluorescein antibodies. The sensor detects fluorescein concentration on a level of 1-10 ng/mL and bovine serum albumin- fluorescein conjugate on a level of 1-5 ng/mL. The proposed device has good prospects for use for early diagnostics of various diseases.
Micromagnetic calculations are compared with faster model calculations of interacting nanoscopic magnetic islands representing an element of a shakti spin ice lattice. Several pathways for transitions between equivalent ground states are studied. The model calculations describe the interaction between the islands either with the point dipole approximation, or with a dumbbell approximation where the distance between the two poles is optimized to match the micromagnetic results. The closest agreement in the energy of both local minima as well as transition state configurations where one macrospin has rotated by 90 degrees is obtained with a dumbbell model where the distance between the poles is ca. 20 % smaller than the island length.
Abstract A model of a magnetically controlled linear polarizer of terahertz (THz) waves based on a cell filled with a magnetic fluid and controlled by an external magnetic field was proposed. The magnetic fluid consisted of a synthetic oil with high transparency in the THz range and ferromagnetic alloy microparticles. Selection of the ferromagnetic particles size and concentration, and also parameters of the external magnetic field was conducted. It was shown that when using ferromagnetic particles of 10–35 μm size, a concentration of 10 wt.%, and a magnetic field with induction of 6.7–57.2 mT, the created construction works as a linear polarizer of the THz wave in the ranged from 0.3 to 1.5 THz, with the degree of polarization of the initially non-polarized THz wave transmitted through the cell being at least of 80%.
Abstract The seamless textual input in Augmented Reality (AR) is very challenging and essential for enabling user-friendly AR applications. Existing approaches such as speech input and vision-based gesture recognition suffer from environmental obstacles and the large default keyboard size, sacrificing the majority of the screen’s real estate in AR. In this paper, we propose MyoKey, a system that enables users to effectively and unobtrusively input text in a constrained environment of AR by jointly leveraging surface Electromyography (sEMG) and Inertial Motion Unit (IMU) signals transmitted by wearable sensors on a user’s forearm. MyoKey adopts a deep learning-based classifier to infer hand gestures using sEMG. In order to show the feasibility of our approach, we implement a mobile AR application using the Unity application building framework. We present novel interaction and system designs to incorporate information of hand gestures from sEMG and arm motions from IMU to provide seamless text entry solution. We demonstrate the applicability of MyoKey by conducting a series of experiments achieving the accuracy of 0.91 on identifying five gestures in real-time (Inference time: 97.43 ms).
Silicon carbide is a very promising platform for quantum applications because of the extraordinary spin and optical properties of point defects in this technologically friendly material. These properties are strongly influenced by crystal vibrations, but the exact relationship between them and the behavior of spin qubits is not fully investigated. We uncover the local vibrational modes of the Si vacancy spin qubits in as-grown 4H-SiC. We apply microwave-assisted spectroscopy to isolate the contribution from one particular type of defects, the so-called V2 center, and observe the zero-phonon line together with seven equally separated phonon replicas. Furthermore, we present first-principles calculations of the photoluminescence line shape, which are in excellent agreement with our experimental data. To boost up the calculation accuracy and decrease the computation time, we extract the force constants using machine-learning algorithms. This allows us to identify the dominant modes in the lattice vibrations coupled to an excited electron during optical emission in the Si vacancy. A resonance phonon energy of 36 meV and a Debye-Waller factor of about 6% are obtained. We establish experimentally that the activation energy of the optically induced spin polarization is given by the local vibrational energy. Our findings give insight into the coupling of electronic states to vibrational modes in SiC spin qubits, which is essential to predict their spin, optical, mechanical, and thermal properties. The approach described can be applied to a large variety of spin defects with spectrally overlapped contributions in SiC as well as in other three-and two-dimensional materials.
We present high-resolution electron energy-loss data and theoretical modeling for the vibrational properties of an atomic monolayer of H (D) on the Pt(111) surface. Experimentally we find three loss peaks, in contrast with two peaks visible in the low-coverage case. A three-dimensional adiabatic potential-energy surface at full coverage of hydrogen is obtained through first-principles calculations. When the zero-point energy effects are included, the minimum energy adsorption site is found to be the fcc site just as in the low-coverage case. Vibrational band states for motion in this potential-energy surface are computed and the excited states associated with the observed loss peaks identified.
Abstract Although the origin of the snow is atmospheric, heat and gasses coming from underlying soil affect the concentration of hydrocarbons and elements in snow. For testing the use of snow in geochemical exploration, a test campaign was carried out in three different mineralization types in northern Finland: Au-Co, P-REE and Cu mineralizations. The snow samples were collected from the bottom of snow cover in two consecutive years. Two methods for analysing geochemical signatures of mineralized bedrock were applied to these snow samples: Spatiotemporal Geochemical Hydrocarbons (SGH) and ultra-trace elements determination by single collector high resolution inductively coupled plasma mass spectrometry (SC-HR-ICP-MS). The SGH method is based on detection of the hydrocarbons that are decomposition products of bacteria that use specific mineralization in their growth phase. In the case of the inductively coupled mass spectrometry, the content of a wide range of elements was determined. The results of both methods showed that the traces inherited from the tested mineralization can be observed in snow. The SGH signature located the Au-Co mineralization using an Au template and the Cu mineralization using a Cu template, although low signal repeatability may be the weakness. The response to the P-REE mineralization with a Polymetallic template was unclear. An improvement was achieved by reinterpreting the result with a customized template for REE. In addition, the repeatability with reinterpreted results showed similarities in the results between the sampling rounds. In the case of the SC-HR-ICP-MS method, results for several elements (e.g. As, Cu, Fe) showed a clear response over the mineralized zones for all three mineralization types. Mineral exploration would benefit using of snow as sampling material: this activity leaves virtually no footprint. Further studies are needed to improve the confidence and reliability in the use of snow as a sampling medium in mineral exploration.
We present a combination of theoretical calculations and experiments for the low-lying vibrational excitations of H and D atoms adsorbed on the Pt(111) surface. The vibrational band states are calculated based on the full three-dimensional adiabatic potential energy surface obtained from first-principles calculations. For coverages less than three quarters of a monolayer, the observed experimental high-resolution electron peaks at 31 and 68 meV are in excellent agreement with the theoretical transitions between selected bands. Our results convincingly demonstrate the need to go beyond the local harmonic oscillator picture to understand the dynamics of this system.
Abstract Genetic risk factors play important roles in the etiology of oral, dental, and craniofacial diseases. Identifying the relevant risk loci and understanding their molecular biology could highlight new prevention and management avenues. Our current understanding of oral health genomics suggests that dental caries and periodontitis are polygenic diseases, and very large sample sizes and informative phenotypic measures are required to discover signals and adequately map associations across the human genome. In this article, we introduce the second wave of the Gene-Lifestyle Interactions and Dental Endpoints consortium (GLIDE2) and discuss relevant data analytics challenges, opportunities, and applications. In this phase, the consortium comprises a diverse, multiethnic sample of over 700,000 participants from 21 studies contributing clinical data on dental caries experience and periodontitis. We outline the methodological challenges of combining data from heterogeneous populations, as well as the data reduction problem in resolving detailed clinical examination records into tractable phenotypes, and describe a strategy that addresses this. Specifically, we propose a 3-tiered phenotyping approach aimed at leveraging both the large sample size in the consortium and the detailed clinical information available in some studies, wherein binary, severity-encompassing, and “precision,” data-driven clinical traits are employed. As an illustration of the use of data-driven traits across multiple cohorts, we present an application of dental caries experience data harmonization in 8 participating studies (N = 55,143) using previously developed permanent dentition tooth surface–level dental caries pattern traits. We demonstrate that these clinical patterns are transferable across multiple cohorts, have similar relative contributions within each study, and thus are prime targets for genetic interrogation in the expanded and diverse multiethnic sample of GLIDE2. We anticipate that results from GLIDE2 will decisively advance the knowledge base of mechanisms at play in oral, dental, and craniofacial health and disease and further catalyze international collaboration and data and resource sharing in genomics research.
Abstract This paper analyzes the influences of generational differences in organizational leaders (founders) on work meaningfulness dynamics in the high-tech sector. Based on a novel interpretative phenomenological analysis of five Finnish case firms, we found that generational differences between leaders concerning work meaningfulness visibly existed. The differences manifested themselves in the form of different views concerning material well-being, house ownership, freedom, teamwork, and the general approach to working life (being a co-owner and being an employee). At the same time, we found that issues like job security, temporary contracts, part-time work, and gig working needed to be seen more in-depth instead of assuming their generic negative influence on well-being and work meaningfulness. Finally, the findings reveal that change is the name of the game for many millennial and post-millennial high-tech workers, and they may not necessarily associate these aspects negatively with work meaningfulness.
Abstract Network automation is a necessity in order to meet the unprecedented demand in the future networks and zero touch network architecture is proposed to cater such requirements. Closed-loop and artificial intelligence are key enablers in this proposed architecture in critical elements such as security. Apart from the arising privacy concerns, machine learning models can also face resource limitations. Federated learning is a machine learning-based technique that addresses both privacy and communication efficiency issues. Therefore, we propose a federated learning-based model incorporating the ZSM architecture for network automation. The paper also contains the simulations and results of the proposed multi-stage federated learning model that uses the UNSW-NB15 dataset.
Abstract Doping of materials beyond the dopant solubility limit remains a challenge, especially when spatially nonuniform doping is required. In 2D materials with a high surface‐to‐volume ratio, such as transition metal dichalcogenides, various post‐synthesis approaches to doping have been demonstrated, but full control over spatial distribution of dopants remains a challenge. A post‐growth doping of single layers of WSe2 is performed by adding transition metal (TM) atoms in a two‐step process, which includes annealing followed by deposition of dopants together with Se or S. The Ti, V, Cr, and Fe impurities at W sites are identified by using transmission electron microscopy and electron energy loss spectroscopy. Remarkably, an extremely high density (6.4–15%) of various types of impurity atoms is achieved. The dopants are revealed to be largely confined within nanostripes embedded in the otherwise pristine WSe2. Density functional theory calculations show that the dislocations assist the incorporation of the dopant during their climb and give rise to stripes of TM dopant atoms. This work demonstrates a possible spatially controllable doping strategy to achieve the desired local electronic, magnetic, and optical properties in 2D materials.
Abstract Protons of tens of keV can be resonantly scattered by electromagnetic ion cyclotron (EMIC) waves excited in the magnetosphere, resulting in proton precipitation down to the upper atmosphere. In this study, we report for the first time the ionospheric height-dependent ionization in response to EMIC-associated isolated proton aurora (IPA) using simultaneous space-borne and ground-based measurements. On 06 March 2019, the Polar Orbiting Environmental Satellites observed significant proton precipitation in the dusk sector (MLT ∼ 19), while ground-based magnetometers detected a clear signature of EMIC waves. Meanwhile, the conjugated all sky imager captured an IPA and the nearby Poker Flat incoherent scatter radar (PFISR) showed enhanced electron density in the E region, suggesting a potential consequence of the EMIC wave-driven proton precipitation. The Global Airglow model simulations confirmed the dominant impact of proton precipitation on the ionosphere and agreed well with PFISR observations. This study confirmed physical links from the magnetosphere to the ionosphere through EMIC-driven proton precipitation.
Abstract Aberrant morphological changes in lumbar multifidus muscle (LMM) are prevalent among patients with low back pain (LBP). Motor control exercise (MCE) aims to improve the activation and coordination of deep trunk muscles (eg, LMM), which may restore normal LMM morphology and reduce LBP. However, its effects on LMM morphology have not been summarized. This review aimed to summarize evidence regarding the (1) effectiveness of MCE in altering LMM morphometry and decreasing LBP; and (2) relations between post-MCE changes in LMM morphometry and LBP/LBP-related disability. Cumulative Index to Nursing and Allied Health Literature, MEDLINE, Cochrane Central Register of Controlled Trials, the Physiotherapy Evidence Database, EMBASE and SPORTDiscus were searched from inception to 30 September 2020 to identify relevant randomized controlled trials. Two reviewers independently screened articles, extracted data, and evaluated risk of bias and quality of evidence. Four hundred and fifty-one participants across 9 trials were included in the review. Very low-quality evidence supported that 36 sessions of MCE were better than general physiotherapy in causing minimal detectable increases in LMM cross-sectional areas of patients with chronic LBP. Very low- to low-quality evidence suggested that MCE was similar to other interventions in increasing resting LMM thickness in patients with chronic LBP. Low-quality evidence substantiated that MCE was significantly better than McKenzie exercise or analgesics in increasing contracted LMM thickness in patients with chronic LBP. Low-quality evidence corroborated that MCE was not significantly better than other exercises in treating people with acute/chronic LBP. Low-quality evidence suggested no relation between post-MCE changes in LMM morphometry and LBP/LBP-related disability. Collectively, while MCE may increase LMM dimensions in patients with chronic LBP, such changes may be unrelated to clinical outcomes. This raises the question regarding the role of LMM in LBP development/progression.
Abstract Objective: Atherosclerosis is a key component of cardiovascular diseases. We set out to study here whether genetic ablation of P4H-TM (transmembrane prolyl 4-hydroxylase) could protect against atherosclerosis as does inhibition of the other 3 classical HIF-P4Hs (hypoxia-inducible factor prolyl 4-hydroxylases). Approach and Results: We generated a double knockout mouse line deficient in P4H-TM and LDL (low-density lipoprotein) receptor (P4h-tm−/−/Ldlr−/−) and subjected these mice to a high-fat diet for 13 weeks. The double knockout mice had less atherosclerotic plaques in their full-length aorta than their P4h-tm+/+/Ldlr−/− counterparts and also had lower serum triglyceride levels on standard laboratory diet and high-fat diet, higher levels of IgM autoantibodies against Ox-LDL (oxidized LDL), and significantly higher lipoprotein lipase protein levels in white adipose tissue and sera. RNA-sequencing analysis revealed changes in expression of mRNAs in multiple pathways including lipid metabolism and immunologic response in the P4h-tm−/−/Ldlr−/− livers as compared with P4h-tm+/+/Ldlr−/−. Conclusions: Our data identify P4H-TM inhibition as a potential novel immuno-metabolic mechanism for intervening in the pathology of atherosclerosis, as hypertriglyceridemia is an individual risk factor for atherosclerosis, and IgM antibodies to Ox-LDL and increased lipoprotein lipase have been associated with protection against it.
Observations of fast TeV γ-ray flares from blazars reveal the extreme compactness of emitting regions in blazar jets. Combined with very-long-baseline radio interferometry measurements, they probe the structure and emission mechanism of the jet. We report on a fast TeV γ-ray flare from BL Lacertae observed by VERITAS, with a rise time of about 2.3 hours and a decay time of about 36 minutes. The peak flux at >200 GeV measured with the 4-minute binned light curve is (4.2 ±0.6) × 10-6 photons m-2 s-1, or ∼180% the Crab Nebula flux. Variability in GeV γ-ray, X-ray, and optical flux, as well as in optical and radio polarization was observed around the time of the TeV γ-ray flare. A possible superluminal knot was identified in the VLBA observations at 43 GHz. The flare constrains the size of the emitting region, and is consistent with several theoretical models with stationary shocks.
There are several methods to calculate the radiative and kinetic power of relativistic jets, but their results can differ by one or two orders of magnitude. Therefore, it is necessary to perform a calibration of the jet power, to understand the reasons for these differences (whether wrong hypotheses or intrinsic source variability), and if it is possible to converge to a reliable measurement of this physical quantity. We present preliminary results of a project aimed at calibrating the power of relativistic jets in active galactic nuclei (AGN) and X-ray binaries (XRB). We started by selecting all the AGN associations with known redshift in the Fourth Fermi LAT Gamma-Ray Catalog (4FGL). We then calculated the radiative and/or kinetic powers from available data or we extracted this information from literature. We compare the values obtained for overlapping samples and highlight preliminary conclusions.
Abstract We present the Aurore platform for ultrafast sciences. This platform is based on a unique 20 W, 1 kHz, 26 fs Ti:sapphire laser system designed for reliable operation and high intensity temporal contrast. The specific design ensures the high stability in terms of pulse duration, energy, and beam pointing necessary for extended experimental campaigns. The laser supplies 5 different beamlines, all dedicated to a specific field: attosecond science (Aurore 1), ultrafast phase transitions in solids (Aurore 2 and 3), ultrafast luminescence in solids (Aurore 4), and femtochemistry (Aurore 5). The technical specifications of these five beamlines are described in detail, and examples of the recent results are given.
Observations of fast TeV $\gamma$-ray flares from blazars reveal the extreme compactness of emitting regions in blazar jets. Combined with very-long-baseline radio interferometry measurements, they probe the structure and emission mechanism of the jet. We report on a fast TeV $\gamma$-ray flare from BL Lacertae observed by VERITAS, with a rise time of about 2.3 hours and a decay time of about 36 minutes. The peak flux at $>$200 GeV measured with the 4-minute binned light curve is $(4.2 \pm 0.6) \times 10^{-6} \;\text{photons} \;\text{m}^{-2}\, \text{s}^{-1}$, or $\sim$180% the Crab Nebula flux. Variability in GeV $\gamma$-ray, X-ray, and optical flux, as well as in optical and radio polarization was observed around the time of the TeV $\gamma$-ray flare. A possible superluminal knot was identified in the VLBA observations at 43 GHz. The flare constrains the size of the emitting region, and is consistent with several theoretical models with stationary shocks.
Abstract One of the non-resonant techniques is the free-space measurement technique, which is popular due to its many advantages compared to the other techniques. It allows the transmission and reflection measurements without any physical contact with the sample. This paper discusses the free-space material measurement system in Ku-band which uses the NRW algorithm and Keysight (Formerly Agilent) 85071E software in determining the dielectric properties of materials. The permittivity and permeability of Teflon, FR4, PVC, ABS, Acrylic, polypropylene, polycarbonate, and epoxy were determined using free space measurement setup. For the first, a free-space measurement for Ku-Band is setup. It consists of a vector network analyzer, two horn antennas, sample holder, and Keysight 85071E software. The different role of transmission and reflection measurements on the achievable results is analyzed about experimental uncertainties and different noise scenarios. Results from the two strategies are analyzed and compared. Good agreement between simulation, measurement, and literature was obtained.
Abstract Transforming potential waste materials into high-value-added sustainable materials with advanced properties is one of the key targets of the emerging green circular economy. Natural mica (muscovite) is abundant in the mining industry, which is commonly regarded as a byproduct and gangue mineral flowing to waste rock and mine tailings. Similarly, chitin is the second-most abundant biomass resource on Earth after cellulose, extracted as a byproduct from the exoskeleton of crustaceans, fungal mycelia, and mushroom wastes. In this study, exfoliated mica nanosheets were individualized using a mechanochemical process and incorporated into regenerated chitin matrix through an alkali dissolution system (KOH/urea) to result in a multifunctional, hybrid hydrogel, and film design. The hydrogels displayed a hierarchical and open nanoporous structure comprising an enhanced, load-bearing double-cross-linked polymeric chitin network strengthened by mica nanosheets possessing high stiffness after high-temperature curing, while the hybrid films (HFs) exhibited favorable UV-shielding properties, optical transparency, and dielectric properties. These hybrid designs derived from industrial residues pave the way toward sustainable applications for many future purposes, such as wearable devices and tissue engineering/drug delivery.
Abstract A Smart Campus is a protected area within Smart Cities (Cities 2.0) where physical security of assets is vital for the continuous operation of the university. Concretely, there are specific mission-critical areas on the campus, which should be protected from unauthorized and malicious individuals. This paper describes a sustainable Smart Campus system architecture based on individuals’ spatiotemporal authentication fingerprint, generated by fusing data from mobile GPS devices and CCTV cameras infrastructure to detect malicious user behavior. The system incorporates unobtrusive monitoring to collect data from such individuals. While the system monitors for unauthorized access to restricted locations within the campus area, data are analyzed by an intrusion detection algorithm that sets off alarms and prompts physical evacuation. The efficiency of the proposed system is evaluated by gauging the prediction accuracy of alarms triggered and response time to the actual incidents on the campus. Results are promising for the adoption of the proposed system architecture by universities in Cities 2.0.
Abstract The environmental, hydrological and climate dynamics were assessed in Northern Eurasia during the Holocene. The reconstructions are based on oxygen isotope composition of acustrine diatom silica (δ18Odiatom) preserved in sediment cores from Ladoga, Bolshoye Shchuchye and Emanda lakes. Interpretation of the δ18Odiatom data is supported by a comprehensive study of modern isotope hydrology and analysis of local and regional proxies. The Northern Eurasia δ18Odiatom records are characterized by pronounced short term variations (1.5–5‰), pointing to the unstable climatic and hydrological conditions in the study regions. All records have clearly demonstrated a gradual depletion over the Holocene in their δ18Odiatom values by ~3–4‰, which follows the trend of decreasing summer insolation, as well as the temperature history of the Northern Hemisphere (NH), indicating a positive response of diatom oxygen isotope signal to large-scale climate changes.
Abstract This study presents a set of laboratory experiments to investigate the effect of Cutter Soil Mixing (CSM) method and curing pressures on the tensile strength of a soft clay treated with Air Cooled Blast Furnace Slag (ACBFS) and Industrial Hydrated Lime (IHL). High productivity, minimum vibration, using the in-situ soil as construction material, and high level of quality control are some of the main benefits of CSM method. Three different slurries containing various percentages of ACBFS and IHL were mixed with saturated soft clay due to CSM method to enhance its tensile strength and make it suitable for the construction of deep CSM panels. To simulate high pressure due to the self-weight of the deep CSM panels in the field, a number of high pressure curing devices were designed and built in the laboratory and used for 28 and 56 day pressurised curing of the treated samples. Then an indirect tensile strength test was performed on the treated samples to investigate the effect of mixing method, ACBFS-IHL content, curing pressure and curing time on the tensile strength of the treated material. Finally, X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analysis were conducted to investigate the microstructural and properties of the treated clay. The outcomes demonstrate that using CSM method and curing pressures along with ACBFS-IHL as a chemical stabiliser, increases the tensile strength of treated soft clay up to 35 times, which is significantly higher than the use of chemical stabiliser alone. Moreover, the microstructural analysis results revealed that the main hydration products in the clay treated with ACBFS-IHL is gismondine (C–A–S–H) which is also considered to be responsible for the higher tensile development.
Abstract Purpose: Applying both the dynamic capability and configuration theoretical perspectives, the paper showcases the role of network configuration and dynamics of hybrid offerings in both developed and emerging markets by high-tech firms. Design/methodology/approach: The current paper uses an exploratory qualitative research methodology based on in-depth case studies of three Finnish high-tech firms operating in the medical technology industry globally. Findings: The findings from the study showed that dynamic capabilities such as sensing and customer engagement along with internal coordination and adaptation capabilities are critical to the success of hybrid market offerings. Moreover, dynamic capabilities were found to be influential in those emerging and advanced international markets where case firms were less familiar with market dynamics. Moreover, the configuration of these capabilities within functional units and coordination of marketing and R&D activities can be effective for creating hybrid offerings in international markets. Ultimately, this was found to be the case even though target market selection for hybrid offerings was influenced by the level of convergence and fragmentation of the market. Originality/value: Applying the configuration theory, this is one of the first studies to specifically analyze the differences in organizational network configuration changes in relation to hybrid market offerings in both developed economies and emerging economies. The findings contribute to hybrid market offering literature by pointing out that not only internal capabilities are important for enacting hybrid offerings, but the roles of ecosystems and knowledge centers are also extremely important to develop hybrid offerings. This paper also highlights the criticality of under-studied dynamic capabilities such as market sensing and customer engagement in the context of hybrid offerings in international markets. This showcases the wider role of ecosystems in enabling technology firms to develop hybrid offerings.