Orientation Of Axis Research Articles

Contact Geometry-Dependent Excitonic Emission in Mixed-Dimensional van der Waals Heterostructures.

Manipulation of excitonic emission in two-dimensional (2D) materials via the assembly of van der Waals (vdW) heterostructures unlocks numerous opportunities for engineering their photonic and optoelectronic properties. In this work, we introduce a category of mixed-dimensional vdW heterostructures, integrating 2D materials with one-dimensional (1D) semiconductor nanowires composed of vdW layers. This configuration induces spatially distinct localized excitonic emissions through a tailored interfacial heterolayer atomic arrangement. By precisely adjusting both the axial and sidewall facet orientations of bottom-up grown PbI2 vdW nanowires and by transferring them onto 1L WSe2 flakes, we establish vdW heterointerfaces with either perpendicular or parallel interatomic arrangements. The edge-standing heterojunction, featuring perpendicular PbI2 layers atop WSe2, promotes efficient charge transfer through the edges and coupled localized states, leading to an enhanced redshifted excitonic emission. Conversely, the layer-by-layer heterointerface, where PbI2 layers are in parallel contact with WSe2, exhibits substantial quenching due to deep midgap states in a type-II alignment, as evidenced by power-dependent measurements and first-principle calculations. Our results introduce a method for actively manipulating excitonic emissions in 2D transition metal dichalcogenides (TMDs) through edge engineering, highlighting their potential in the development of various quantum devices.

High-Resolution Cryogenic Spectroscopy of Single Molecules in Nanoprinted Crystals.

We perform laser spectroscopy at liquid helium temperatures (T = 2 K) to investigate single dibenzoterrylene (DBT) molecules doped in anthracene crystals of nanoscopic height fabricated by electrohydrodynamic dripping. Using high-resolution fluorescence excitation spectroscopy, we show that zero-phonon lines of single molecules in printed nanocrystals are nearly as narrow as the Fourier-limited transitions observed for the same guest-host system in the bulk. Moreover, the spectral instabilities are comparable to or less than one line width. By recording super-resolution images of DBT molecules and varying the polarization of the excitation beam, we determine the dimensions of the printed crystals and the orientation of the crystals' axes. Electrohydrodynamic printing of organic nano- and microcrystals is of interest for a series of applications, where controlled positioning of quantum emitters with narrow optical transitions is desirable.

A signal energy-based approach for acoustic source localization in composite laminates

Composite laminates are widely used in various fields, but their structural properties make them prone to impact damage. Thus, the real-time localization of the impact source in composite laminates is of great importance. The signal energy-based approach for acoustic source localization, as a new technique proposed in recent years, has advantages in that it can be applied in the case of low signal-to-noise ratio and does not need to have a priori knowledge of material properties. In this paper, an acoustic source localization technique for composite laminates based on an improved signal energy-based approach is proposed. The prior knowledge of the orientation of the symmetry axes of the composite laminate is not needed. The proposed approach is verified by numerical simulation and experiment. The results show that proposed approach has good stability and accuracy. The error analysis and suggestions for improving the feasibility of this technique are also given.

Vp/Vs structure and Pn anisotropy across the Louisville Ridge, seaward of the Tonga-Kermadec Trench

The Pacific Plate within the collision zone between the Louisville Ridge and the Tonga-Kermadec Trench was formed at the Osbourn Trough, a paleo spreading center that became inactive during the Cretaceous. In this region, the trench shallows from a depth of 8–11 km to ∼6 km below sea surface, while the outer rise topography is obscured by Louisville seamounts that rise 4–5 km above the adjacent seafloor. We derive 2-D P-wave (Vp) and S-wave (Vs) velocity-depth models along a wide-angle seismic profile oriented sub-parallel to the trench axis, intersecting the 27.6°S seamount. The seismic profile is located in the down-going Pacific Plate eastwards from the trench axis (∼100 km distant at the south end and ∼ 150 km at the north end), where bending-related faulting is limited or absent. Using the derived P- and S-wave velocity-depth models we calculate the corresponding Vp/Vs ratio model which shows values of 1.7–1.85 throughout the oceanic crust either side of the Louisville Ridge where it is unaffected by magmatism associated with its formation. This range of observations lies within those documented by laboratory measurements on basalt, diabase, and gabbro. Conversely, in the vicinity of the summit of 27.6°S seamount, the relatively elevated Vp/Vs (∼1.9) ratio observed can be attributed to water-saturated cracks within the shallow sub-seabed section of the intrusive core. Beneath the seamount the uppermost mantle has a Vp ranging from 8.0 to 8.9 km/s. Comparing our P-wave model with a pre-existing model running sub-perpendicularly along the Louisville Ridge axis, we observe an anisotropy of up to ∼6% at a depth of 3–4 km below the Moho. The predominant orientation of the faster axis follows the direction of paleo spreading flow when the plate was formed at the Osbourn Trough.

Optimization of retarder parameters for switchable privacy mode automotive displays under asymmetric viewing conditions

A switchable privacy mode (SPM) display should not be seen by a driver during driving (privacy mode), but it needs to be seen by the driver and a co-driver when a car is stopped (share mode). In this work, a SPM display was designed using a bottom twisted-nematic (TN) liquid crystal display (LCD) and a top in-plane switching (IPS) LCD where a half-wave plate (HWP) is located between the two LCD panels. The SPM display in front of the co-driver was considered, which is seen under asymmetric viewing conditions. The orientation of the slow axis, retardation dispersion, and biaxiality of the retarder were varied to maximize the SPM’s optical performance in the driver’s and co-driver’s viewing directions. Transmittance at the driver’s viewing direction can be reduced from 4.22 to 0.03% in privacy mode by replacing the positive dispersion retarder with a negative dispersion retarder.

When the Anomalistic, Draconitic and Sidereal Orbital Periods Do Not Coincide: The Impact of Post-Keplerian Perturbing Accelerations

In a purely Keplerian picture, the anomalistic, draconitic and sidereal orbital periods of a test particle orbiting a massive body coincide with each other. Such degeneracy is removed when post-Keplerian perturbing acceleration enters the equations of motion, yielding generally different corrections to the Keplerian period for the three aforementioned characteristic orbital timescales. They are analytically worked out in the case of the accelerations induced by the general relativistic post-Newtonian gravitoelectromagnetic fields and, to the Newtonian level, by the oblateness of the central body. The resulting expressions hold for completely general orbital configurations and spatial orientations of the spin axis of the primary. Astronomical systems characterized by extremely accurate measurements of orbital periods like transiting exoplanets and binary pulsars may offer potentially viable scenarios for measuring such post-Keplerian features of motion, at least in principle. As an example, the sidereal period of the brown dwarf WD1032 + 011 b is currently known with an uncertainty as small as ≃10−5s, while its predicted post-Newtonian gravitoelectric correction amounts to 0.07s; however, the accuracy with which the Keplerian period can be calculated is just 572 s. For double pulsar PSR J0737–3039, the largest relativistic correction to the anomalistic period amounts to a few tenths of a second, given a measurement error of such a characteristic orbital timescale as small as ≃10−6s. On the other hand, the Keplerian term can be currently calculated just to a ≃9 s accuracy. In principle, measuring at least two of the three characteristic orbital periods for the same system independently would cancel out their common Keplerian component, provided that their difference is taken into account.

Single crystal, conformational, quantum reactivity, hirshfeld surface, molecular interactions, ADMET, and molecular docking investigations on HIV-1 site of 3-isopropyldiphenyl-1-(2-(thiophen-2yl)acetyl)piperidin-4-one

The 3-isopropyl-2,6-diphenyl-1-(2-(thiophen-2yl)acetyl)piperidin-4-one (IPTP) single crystals were grown by slow evaporation method and the structure is confirmed through FT-IR, 1H NMR, and 13C NMR spectral analyses. Single crystal X-ray diffraction revealed that the title compound having chair conformation of the piperidine ring, with an axial orientation of phenyl rings at C-2 and C-6 positions and an isopropyl group at C-3. Hirshfeld surface analysis was employed to examine intermolecular contacts and strong and weak attractive, repulsive, and van der Waals interactions in the molecule were determined using the reduced density gradient method (RDG). The geometrical parameters obtained through Density Functional Theory are compared with experimental values and also conducted to optimize structural parameters, frontier molecular orbitals (FMOs), and molecular electrostatic potential surface analysis (MEPS). NBO calculations were employed to investigate intermolecular and intramolecular charge movement, as well as the molecule's stability. Vibrational Energy Distribution Analysis (VEDA) software facilitated potential energy decomposition (PED) analysis using FT-IR wave numbers. The title compound molecular docking data were compared with the markedly available FDA-approved anti-HIV drug of Nelfinavir and their results were discussed, ADME analysis studies were discussed concerning FDA-approved anti-HIV drugs, including Nelfinavir, Betulinic Acid, Haloperidol, and Donepezil.

Multi-scale variations of subglacial hydro-mechanical conditions at Kongsvegen glacier, Svalbard

Abstract. The flow of glaciers is largely controlled by changes at the ice–bed interface, where basal slip and sediment deformation drive basal glacier motion. Determining subglacial conditions and their responses to hydraulic forcing remains challenging due to the difficulty of accessing the glacier bed. Here, we monitor the interplay between surface runoff and hydro-mechanical conditions at the base of the Kongsvegen glacier in Svalbard. From July 2021 to August 2022, we measured both subglacial water pressure and till strength. Additionally, we derived median values of subglacial hydraulic gradient and radius of channelized subglacial drainage system from seismic power, recorded at the glacier surface. To characterize the variations in the subglacial conditions caused by changes in surface runoff, we investigate the variations of the following hydro-mechanical properties: measured water pressure, measured sediment ploughing forces, and derived hydraulic gradient and radius, over seasonal, multi-day, and diurnal timescales. We discuss our results in light of existing theories of subglacial hydrology and till mechanics to describe subglacial conditions. We find that during the short, low-melt-rate season in 2021, the subglacial drainage system evolved at equilibrium with runoff, increasing its capacity as the melt season progressed. In contrast, during the long and high-melt-rate season in 2022, the subglacial drainage system evolved transiently to respond to the abrupt and large water supply. We suggest that in the latter configuration, the drainage capacity of the preferential drainage axis was exceeded, promoting the expansion of hydraulically connected regions and local weakening of ice–bed coupling and, hence, enhanced sliding.

Precyzyjne wyznaczanie geodezyjne w budowie obiektów inżynierskich z orientacją w określonym kierunku

In the construction practice, there are engineering structures, where some complex requirements in the process of their building have to be meet, e.g., their positioning, geographical orientation and geometric determination. The current publication examines the specificity of geodetic activities, regarding the orientating of the main construction axes of the foundation and the supporting structures of the terrestrial telecommunication antennas in a predetermined direction, for example, in the parallel direction to the geographical meridian. The focus is on the assessment of the accuracy and the choice of appropriate methods and equipment in order to create the required geodetic network, as well as to perform accurate setting out works. The combination of demands, namely for a specific geographic orientation and precise relative accuracy of the setting elements, implies a suitable transition from the ellipsoidal geodetic coordinates to the projection plane of the setting out project. In this connection, the influence of the meridian convergence on the accuracy of the planning setting out works is examined. A mathematical approach is proposed to assess the need of elimination of this factor, depending on the value of the constructional tolerance and the geographic location of the site.The necessary precision for determining the geodetic ellipsoidal coordinates by GNSS (Global Navigation Satellite System) measurements as well as the required accuracy of the planning and elevation setting out works are shown.Using different geodetic methods and tools, a preliminary accuracy assessment approach and the choice of the appropriate coordinate projection and height reference system is also proposed. The real data, which were obtained in different Earth’s locations by the explained methodology, are presented. The established geodetic networks provide orientation of the main construction axes of the bases of the terrestrial communication antennas in the parallel direction to the geodetic meridian with an azimuth standard error - МА = ± 2÷5' (minutеs) and allowable error in distances and eleventions of the setting out elements, respectively - MdS ≤ ±3 mm, Mdh ≤ ± 2 mm.

Selecting Flap Transfer Methods to Repair Helix Soft Tissue Defect Based on the Direction of Long Axis.

The posterior auricular flap has long been favored for repairing skin defects on the ear's surface. However, achieving optimal esthetic outcomes in ear reconstruction requires a flexible approach to flap transfer methods. While bipedicle advancement flaps are commonly used for body wound coverage, they are rarely used in auricular defect repair. To propose a modified flap transfer approach based on the orientation of the auricular defect's long axis and assess the postoperative esthetic outcomes. The authors reported 12 patients treated using 2 distinct flap transfer techniques. Mild to moderate helix soft tissue defects remained after excision of the masses. A direct island flap was created for patients with longitudinal defects to cover the defect. For patients with transverse defects, a combination of bipedicle and island flaps was used for repair. Scar quality and esthetic outcomes were assessed at least 6 months postsurgery using the Scar Cosmesis Assessment and Rating scale. All patients experienced no serious complications and achieved excellent cosmetic results. Patients undergoing combined flap transfer exhibited relatively more favorable esthetic outcomes. The authors propose a novel concept for repairing helix soft tissue defects by designing local flaps based on the direction of the defect's long axis. For repairing helix soft tissue defects with a long axis parallel to the auricular edge, the combined utilization of bipedicle advancement flap and island rotation flap transfer should be consideration more.

Visualization enhancement by PCA-based image fusion for skin burns assessment in polarization-sensitive OCT.

Polarization-sensitive optical coherence tomography (PS-OCT) is a functional imaging tool for measuring tissue birefringence characteristics. It has been proposed as a potentially non-invasive technique for evaluating skin burns. However, the PS-OCT modality usually suffers from high system complexity and relatively low tissue-specific contrast, which makes assessing the extent of burns in skin tissue difficult. In this study, we employ an all-fiber-based PS-OCT system with single-state input, which is simple and efficient for skin burn assessment. Multiple parameters, such as phase retardation (PR), degree of polarization uniformity (DOPU), and optical axis orientation, are obtained to extract birefringent features, which are sensitive to subtle changes in structural arrangement and tissue composition. Experiments on ex vivo porcine skins burned at different temperatures were conducted for skin burn investigation. The burned depths estimated by PR and DOPU increase linearly with the burn temperature to a certain extent, which is helpful in classifying skin burn degrees. We also propose an algorithm of image fusion based on principal component analysis (PCA) to enhance tissue contrast for the multi-parameter data of PS-OCT imaging. The results show that the enhanced images generated by the PCA-based image fusion method have higher tissue contrast, compared to the en-face polarization images by traditional mean value projection. The proposed approaches in this study make it possible to assess skin burn severity and distinguish between burned and normal tissues.

Micro-seismicity associated with CO2 geological storage activities in Hontomín, Spain

We present the first local micro-seismicity catalogue including focal mechanisms for the Hontomín plant, the only site of its kind in Spain and one of the very scarce CO2 storage facilities in Europe. The catalogue reveals a correlation between micro-seismicity occurrence and bottom hole pressure (BHP) at the injection well. A burst of micro-seismicity ranging from -1 to 0.4 ML, thus imperceptible to human senses, took place coeval with the longest duration test of the period studied when the BHP was the highest. Events clustered at ∼ 0.4 km below the well bottom hole. Focal mechanisms could be well resolved for 3 events with similar results, showing a strong strike-slip component and a minor reverse component, with similarly oriented nodal planes. The local stress fields inverted from the focal mechanism solutions exhibit an orientation of the maximum horizontal stress axis (SHmax) that ranges from NE to ESE and differs from the principal stress orientations obtained in previous works for the same area. The micro-seismicity locations and tensors obtained are useful inputs to models aiming to better understand the deformation effects of fluids’ injection underground.

A novel indicator for equivalent mean air temperature within the tunnel considering time-varying ventilation wind speeds: Calculation and application

The study examines the coupling effect between air temperature and time-varying ventilation wind speeds within the tunnel, abstracting their influence on tunnel coldness. This investigation introduces a novel indicator—the equivalent mean air temperature within the tunnel—derived through fluid dynamics and heat transfer theories based on the principle of equivalent convective heat transfer. Case studies using the Xinjiaodong Tunnel and BSLL Tunnel illustrate the indicator's applications, including optimal anti-freezing axis identification, insulation layer thickness design, and active-controlled ventilation implementation. The optimal anti-freezing axis orientation angle for the Xinjiaodong Tunnel entrance section is 133.3°, deviating significantly by 160.8° from the actual axis, indicating a lower level of equivalent mean annual air temperature (5.5 °C) at the entrance section. This underscores the necessity to reinforce anti-freezing measures specifically at the entrance section of the Xinjiaodong Tunnel. Determining a 10 cm-thick insulation layer requirement at the Xinjiaodong Tunnel entrance section based on the equivalent mean air temperature. Through on-site investigation and published findings, it was observed that a 5 cm-thick insulation layer failed to prevent freezing, resulting in water leakage and ice formation on the lining, thus validating the calculation results. The BSLL Tunnel requires an insulation layer thickness exceeding 10 cm based on the equivalent mean air temperature, necessitating the implementation of active-controlled ventilation. Calculation results reveal that, with active-controlled ventilation wind speeds increasing from 1 m/s to 4 m/s at a temperature threshold of 4 °C, the equivalent mean air temperature during cumulative negative temperature periods within the BSLL Tunnel rises sharply from 1.0 °C to 2.7 °C. These findings demonstrate that the equivalent mean air temperature not only guides the identification of optimal anti-freezing axis, the design of insulation layer thickness considering time-varying ventilation wind speeds, and the implementation of active-controlled ventilation but also provides new methods and technologies for anti-freezing design in cold-region tunnels.

Design and construction of high strength double network hydrogel with flow-induced orientation

The design and construction of high strength hydrogels is a widely discussed topic in hydrogel research. In this study, we combined three toughening strategies, including dual network, oriented structure construction and nanophase doping, to develop an alginate/polyacrylamide (PAM)/modified titanium dioxide fiber (TiO2 NF@PAM) dual network composite hydrogel prepared via syringe. The effects of different preparation methods, AM/Alginate ratios, inorganic doping phases and TiO2 NF@PAM/AM ratios on the mechanical properties of composite hydrogels were investigated. The study found that the alginate hydrogel prepared by syringe exhibited superior axial orientation and achieved a tensile strength of (1091 ± 46) kPa. And the composite hydrogel doped with 0.2 wt% TiO2 NF@PAM had a tensile strength of (1006 ± 64) kPa, which was higher than that of the composite hydrogel doped with 0.2 wt% TiO2 nanoparticles (976 ± 66) kPa. The highest tensile strength (1120 ± 67) kPa and elongation at break (182 ± 8) % were achieved when the ratio of TiO2 NF@PAM/AM was 0.6 wt%. The force applied to the gel solution in the syringe affects the orientation of the polymer chains and TiO2 NF@PAM within the gel, which subsequently impacts the mechanical properties of the hydrogel. Therefore, we further investigated the mechanical properties of composite hydrogels under varying propulsion speeds, syringe diameters, and syringe lengths. It was observed that the gel solution’s shear strength increased as the syringe diameter decreased. The resulting composite hydrogels were better oriented and had improved mechanical properties. The composite hydrogels’ tensile strength peaked at (1117 ± 47) kPa when the syringe advance rate was between 1–7 mL/min. The mechanical properties of the hydrogels were optimal when the syringe length was 30 mm, with a maximum tensile strength of (1131 ± 67) kPa and a tensile ratio of (166 ± 5) %. This study demonstrates the viability of integrating three distinct strengthening methodologies to generate hydrogels of considerable strength. Furthermore, the Alginate/PAM/TiO2 NF@PAM composite hydrogels possess remarkable potential as adaptable, wearable sensors due to their exemplary mechanical properties, knittability, and conductivity.

Constraints on Bianchi-I type universe with SH0ES anchored Pantheon+ SNIa data

We study the Bianchi-I cosmological model motivated by signals of statistical isotropy violation seen in cosmic microwave background (CMB) observations and others. To that end, we consider various kinds of anisotropic matter that source anisotropy in our model, specifically Cosmic strings, Magnetic fields, Domain walls and Lorentz violation generated magnetic fields. These anisotropic matter sources, taking one at a time, are studied for their co-evolution with standard model (isotropic) sources viz., dust-like (dark/normal) matter, and dark energy modelled as cosmological constant. We constrain the Hubble parameter, density fractions of anisotropic matter, cold dark matter (CDM), and dark energy (Λ) in a Bianchi-I universe with planar symmetry i.e., which has a global ellipsoidal geometry, and try to find signatures of a cosmic preferred axis if any.The latest compilation of Type Ia Supernova (SNIa) data from Pantheon+SH0ES collaboration is used in our analysis to obtain constraints on cosmological parameters and any preferred axis for our universe.In our analysis, we found mild evidence for a cosmic preferred axis. It is interesting to note that this preferred axis lies broadly in the vicinity of other prominent cosmic anisotropy axes reported in the literature from diverse data sets.Also we find some evidence for non-zero (negative) cosmic shear and eccentricity that characterize different expansion rates in different directions and deviation from an isotropic scale factor respectively.The energy density fractions of two of the sources considered are found to be non-zero at a2σ confidence level.To be more conclusive, we require more SNIa host galaxy data for tighter constraints on distance and absolute magnitude calibration which are expected to be available from the future JWST observations and others.

Brittney Griner, Intersectionality, and “Woke Politics”: A Critical Examination of Brittney Griner’s Return to the United States

In February of 2022, professional women’s basketball player Brittney Griner was detained in Russia on drug possession charges. Her detainment was a trending Twitter topic demonstrating the cultural, political, and social state of the United States, specifically pertaining to race, gender, nationality, and LGBTQ matters. The purpose of this study was to analyze what Brittney Griner’s release from Russia tells us about social power relations and contemporary social political matters on the axis of race, gender, and sexual orientation. We organized the data to determine three distinct, yet interconnected themes: (a) Woke Politics at the Intersection of Race, Gender, and Queerness; (b) Preferential Treatment at the Expense of Whiteness Informed Patriotism; and (c) Intersectionality as Political Pandering.

Influence of atmospheric rivers on extreme precipitation in western Ukraine

Formulation of the problem. In recent years, interest in the atmospheric river (AR) phenomenon is growing, as more and more researchers associate it with extreme precipitation. Relatively few works are devoted to the assessment of the influence of atmospheric rivers on precipitation in Eastern Europe. The purpose of the article is to assess the occurrence of atmospheric river events during extreme precipitation in the western regions of Ukraine (Lviv and Volyn regions) and to analyze the geographical features of the spatial distribution of atmospheric river bends during extreme precipitation. Methods. We used the catalog of atmospheric rivers identified according to the methodology of D. Walliser and B. Guan to analyze the occurrence of atmospheric river events on the territory of the western part of Ukraine. Also, we used the sample of days with extreme precipitation (greater than 95th percentile for each meteorological station and each month) in the Lviv and Volyn oblasts of Ukraine to match it with AR episodes. It is shown that in most cases extreme precipitation events were accompanied by the atmospheric river phenomenon detected on the territory of Ukraine or the bordering territories. Results. The typical shape of atmospheric river bends during extreme precipitation most often is arc-shaped while the typical spatial coverage stretched from North Africa through the Mediterranean Sea and Turkey to the territory of Ukraine. Less often, the form of detected AR area had the form of a meridional bend extending from the eastern part of the Mediterranean Sea towards Ukraine. However, the analysis showed that the presence of atmospheric river phenomenon is not the exceptional reason for extreme precipitation. Part of the extreme precipitation events is associated with specific synoptic situations (precipitation caused by cold fronts or occluded fronts) whereas conditions for atmospheric river detection are not fulfilled (bend size, meridional flow component, flow intensity). Atmospheric river episodes were not observed at most of the days of general sample (on average 72.36%) within the study area based on the period of 1991-2020. At the same time, precipitation events in the absence of AR were recorded on average in 32.2% of days (relative to the total number of days). In the presence of AR, precipitation was not recorded in about a third of cases. In the sample of days in the absence of AR and in the presence of AR, the proportion of precipitation of different gradations is as follows: for 10-20 mm is 2.73% and 2.64% respectively; for 20-50 mm is 1.37% and 1.63%; more than 50 mm is 0 .19% against 0.16%. In the spring, there is a certain consistency with the negative daily value of the NAO index and the AR axis orientation from the southwest to the territory of Ukraine. Thus, within 5 days before the localization of AR on the territory of Ukraine, values of the NAO index <-0.5 are noted, but the index changes in the process of the pressure field change. Based on a limited sample of extreme precipitation (94 cases), we assessed the correspondence of the precipitation rate to the area of atmospheric rivers and their features of the spatial orientation. ARs extending from the southwest (north of Africa) and the south (western part of the Mediterranean Sea) are characterized by the greatest recurrence. No regularities were found either concerning the dependence of the precipitation rate on the orientation of the AR, or concerning the dependence of the number of stations with extreme precipitation on the orientation of the AR. No linear dependence was found for the area of atmospheric rivers within both the study region and the territory of Eastern and Southeastern Europe with daily precipitation in the western regions of Ukraine.

Body mass index and astigmatism: A nationwide study.

Existing research on the relationship between body mass index (BMI) and astigmatism yields inconsistent results. This study analyses this association in a nationally representative sample of adolescents. This retrospective, cross-sectional study included Israeli adolescents who underwent medical assessments before mandatory military service between 2011 and 2022. BMI was categorised based on the US age- and sex-matched percentiles. Astigmatism was categorised by magnitude [low-moderate: 0.75 to <3.00 diopters (D), high: ≥3.00 D], and axis orientation [with-the-rule (WTR), against-the-rule (ATR), or oblique (OBL)]. Sex-stratified regression models adjusted for sociodemographic variables were used. Of 935 989 adolescents evaluated, 887 325 were included [511 465 (57.6%) males, mean age 17.2 years]. Astigmatism was diagnosed in 123 675 (13.9%) adolescents, of whom 117 081 (13.2%) had low-moderate and 6594 (0.7%) had high astigmatism. WTR astigmatism was the most prevalent (8.2%), followed by ATR (4.1%) and OBL (1.6%) types. Compared with low-normal BMI (5th to 50th percentile), the adjusted ORs for total astigmatism increased with increasing BMI, peaking at 1.65 (1.57-1.74) in males and 1.74 (1.64-1.86) in females with severe obesity. ORs were accentuated for high astigmatism, reaching 3.51 (3.01-4.09) in males, and 3.45 (2.83-4.22) in females with severe obesity. WTR astigmatism demonstrated the strongest association with BMI, with ORs reaching 2.26 (2.13-2.40) in males and 2.04 (1.90-2.20) in females with severe obesity. The results persisted in a series of subgroup analyses. Obesity is associated with higher odds of astigmatism in adolescence. Further investigation into the role of weight management in astigmatism development is warranted.

Elastic deformation analysis of rotational wood-dowel welding joint system based on the variational method

Abstract This study aimed to investigate the elastic deformation of rotational wood-dowel welding joints by using the variational method, as there was no efficient tool to access the deformation behavior of welding joints perpendicular to axis orientation so far. Based on the variational method, the displacement control equation of axially-loaded dowel-welded wood joints was derived. By incorporating the boundary conditions and using an iterative approach, the parameters required in the control equation were determined. The analytical expression ϕ(r) for the deformation function of the wood substrate under elastic conditions was proposed, thereby determining the displacement and axial force of the single wood-dowel. The elasticity modulus was the primary influence parameter on the function ϕ(r). However, the welding depth had a more critical impact, and reasonable combination of parameters could lead to a better interaction between the wood dowel and substrate. The comparison between calculated results and test trials collected from the previous studies indicated that the elastic solution method could accurately estimate the pull-out ultimate bearing capacity and deformation characteristics of the welding joints. This work can provide unique perspective to understand the technology of rotational wood-dowel welding joints, and a good reference suggestion for the manufacture of multi-dowel welding joints.

Negative reflection and total internal reflection at the internal surface of lithium niobate crystal

In this paper we analytically find out the expression for the wave vector and Poynting vector in the reflection domain for negative uniaxial material. We investigate the impact of the optical axis rotation and incident angle on the wave vector and Poynting vector reflected from the internal surface of lithium niobate crystal when the light is propagating from the denser anisotropic medium to the rarer isotropic medium. We derive the Brewster angle condition and discuss the walk-off between TE and TM polarized light. We explore where the wave vector and Poynting vector are parallel after reflection. In further analysis, we look into the phase differences between ordinary and extraordinary reflected light after total internal reflection from the internal surface of lithium niobate crystal. The necessary conditions for linear polarization and circular polarization have been established. The impact of optical axis orientation is also taken into consideration. The refractive index for the isotropic material for the desired polarization response has been found as 2.18, 2.1, and 2.03 at 632 nm, 1550 nm, and 3500 nm, respectively.