Horizontal Tilt Research Articles

Tectonic reevaluation of West Cameroon domain: Insights from high-resolution gravity models and advanced edge detection methods

The West Cameroon region, characterized by a diverse geomorphology of highlands and plains resulting from tectonic processes across different geological ages, has been extensively explored for natural resources. Recognizing the significance of its tectonic and magmatic features associated with seismic and volcanic activity, this study focuses on geodynamic investigations of the Cameroon Volcanic Line (CVL). Despite previous efforts, detailed structural geophysical studies of the West Cameroon domain have proven inconclusive, prompting a comprehensive structural reinterpretation. Utilizing the high-resolution SGG-UGM-2 satellite gravity model and innovative processing techniques, including the horizontal gradient of a modified tilt (HGSTDR), the balanced horizontal gradient (BHG), the tilt of the horizontal gradient (TAHG), the improvised horizontal gradient tilt angle (impTAHG), and the Tilt Depth method, our research aims to enhance the interpretational quality of tectonic lineaments. By separating regional and residual anomalies in the Bouguer gravity map and applying a combination of filters to delineate geological units, the BHG filter emerges as a robust tool that highlights subsurface edges without generating false features. This approach unveils previously undetected NNW-SSE-oriented lineaments, confirming the presence of deep fractures and faults in Bafoussam, Nkongsamba, and along the Benue Trough, corroborated by newly discovered NNW-SSW trending lineaments. The study suggests that the region’s topography is overcompensated by deep mountain roots and compressive tectonism. Digitizing the BHG filter produces a structural map, revealing predominant NE trends in identified geological margins, including NNE-SSW, N-S, NW-SE, E-W, and NE-SW directions. Geological contacts between granite and high-grade gneiss are indicated by NNW-SSE and NNE-SSW trending lineaments along the Benue Trough. These results contribute significantly to the understanding of the tectonic setting of the West Cameroon Domain.

The Magnetic Anomaly Map of Paraná State: An Integration of Airborne Surveys Performed Over the Years

Over the last decades, several aerial survey campaigns have been conducted in the State of Paraná. However, we did not have a complete magnetic data integration and analysis focused on the Paraná’s geological context. Therefore, the main objective of this work is to provide the integration of all available data and realize a general analysis to make the Integrated Magnetic Map of the Paraná State, in collaboration with the Geological Survey of Brazil (SGB-CPRM). After integrate the data we have applied processing techniques on public airborne magnetic data, available from the Geological Survey of Brazil database (GeoSGB). For this integration, it was used the minimum curvature interpolation, with cell sizes according to each survey. All gridded data was extrapolated upward from the original height to the altitude of 1800 m. Afterwards, we applied the upward continuation for 2700 m and the following filters: vertical gradient (VDR), total horizontal derivative (THDR), analytic signal (AS), or tilt derivative (TDR), tilt angle of the horizontal derivative (TAHG) and vertical integral of the analytic signal (VIAS). The final results provide valuable maps (and grids) that can be used by the community for future works. In this work we tried to do a simple overview of the structural framework of Paraná State, representing the main magnetic structures of the Paraná State basement and compare them with the most important structures already mapped in surface over the years. All the data present in this work and other filters tests are available and can be access in the supplementary material (https://acervodigital.ufpr.br/ https://hdl.handle.net/1884/89075 and also at zenodo repository https://doi.org/10.5281/zenodo.12820642).

Gravity and magnetism of southern Africa in relation to Craton structures and belts

The general tectonic structural architecture of southern Africa is an ensemble comprised of Kalahari Craton, a vast range of mosaics of the best-preserved geological Belts, and exposed crustal blocks. In the region, demarcation of geological boundaries, tracing of magnetic and gravitational bodies, and detrending lineaments are essential to understanding the structural limits. The study presents the prevalent gravitational and magnetic investigation of major geological Belts, enhancing edges of Cratons, and evaluation of surface invariants to improve the geological understanding and evaluate the correlation of structures with the general structural tectonic framework. The utilized filter methods in the gravity maps are the Directional derivatives along x, y, and z-directions, the Modulus tensor, the Total horizontal derivative, and the Tilt angle techniques.The phase-based filters used in the magnetic section include the Total horizontal derivative, Analytical signal, Tilt angle method, Tilt of total horizontal derivative, Theta method, Horizontal tilt angle method, Enhanced tilt filter, and Enhanced total derivative of the tilt angle. The Directional derivatives of the gravity field and the Modulus of the gravity gradient tensor demarcate the boundaries of geological structures. The Total horizontal derivative method gives an immediate and easy-to-read image of the linear structures and fault systems. The signal cluster on the Analytical signal and Tilt angle maps delineate the boundaries of causative geological sources. The Theta map is comparable with the enhanced total derivative of the tilt angle. The Tilt of the total horizontal derivative, Theta map, and Enhanced tilt filter accentuate the traces of magnetic bodies, including the Cratons. The study finds regional lineaments surrounding the Cratons and concentrated along the geological Belts. The approach of using joint elegant filters is effective and increases the certainty of the interpretation.

An Adjustment Strategy for Tilted Moiré Fringes via Deep Q-Network

Overlay accuracy, one of the three fundamental indicators of lithography, is directly influenced by alignment precision. During the alignment process based on the Moiré fringe method, a slight angular misalignment between the mask and wafer will cause the Moiré fringes to tilt, thereby affecting the alignment accuracy. This paper proposes a leveling strategy based on the DQN (Deep Q-Network) algorithm. This strategy involves using four consecutive frames of wafer tilt images as the input values for a convolutional neural network (CNN), which serves as the environment model. The environment model is divided into two groups: the horizontal plane tilt environment model and the vertical plane tilt environment model. After convolution through the CNN and training with the pooling operation, the Q-value consisting of n discrete actions is output. In the DQN algorithm, the main contributions of this paper lie in three points: the adaptive application of environmental model input, parameter optimization of the loss function, and the possibility of application in the actual environment to provide some ideas. The environment model input interface can be applied to different tilt models and more complex scenes. The optimization of the loss function can match the leveling of different tilt models. Considering the application of this strategy in actual scenarios, motion calibration and detection between the mask and the wafer provide some ideas. To verify the reliability of the algorithm, simulations were conducted to generate tilted Moiré fringes resulting from tilt angles of the wafer plate, and the phase of the tilted Moiré fringes was subsequently calculated. The angle of the wafer was automatically adjusted using the DQN algorithm, and then various angles were measured. Repeated measurements were also conducted at the same angle. The angle deviation accuracy of the horizontal plane tilt environment model reached 0.0011 degrees, and the accuracy of repeated measurements reached 0.00025 degrees. The angle deviation accuracy of the vertical plane tilt environment model reached 0.0043 degrees, and repeated measurements achieved a precision of 0.00027 degrees. Moreover, in practical applications, it also provides corresponding ideas to ensure the determination of the relative position between the mask and wafer and the detection of movement, offering the potential for its application in the industry.

A Novel Method of Magnetic Sources Edge Detection Based on Gradient Tensor

The edge detection method based on the magnetic gradient tensor data plays an important role in magnetic exploration because it is free from geomagnetic interference and contains more abundant information. This paper proposes a new anomaly edge detection method using the magnetic gradient tensor components. The model is established to compare with other methods, such as directional total horizontal derivative (THDz), analytical signal (AS), tilt angle, theta map, and so on, under conditions of vertical magnetization, oblique magnetization, and noise interference. Through the study of the anomaly distribution of the rectangular model, it is observed that the edge detection method proposed in this paper is nearly impervious to noise interference, exhibits strong anti-interference capabilities, delivers a high-quality boundary identification effect, and provides greater accuracy in anomaly edges with minimal error. When multiple anomalous bodies are present, the edge detection results are less susceptible to interference from each other, resulting in higher resolution. The efficiency of the algorithm is demonstrated by real magnetic data from some study areas in Jiangxi Province, China. The experimental results show that the proposed method is more precise and accurate than the total horizontal derivative, analytical signal, tilt angle, and theta map methods.

Method for defining the horizontal plane in fluoroscopic kinematic analysis

PurposeIn vivo kinematics of skeletal joints and prostheses is affected by gravity; therefore, absolute tilt must be taken into account. However, current fluoroscopic kinematic analysis cannot measure the tilt. This study introduces and validates a method for defining the horizontal plane in fluoroscopy systems to measure the tilt of an object. MethodsA rectangular metal plate (200 ​× ​200 ​× ​10 ​mm) with a flatness of 0.03/100 ​mm was horizontally adjusted using a leveler (sensitivity of 0.02° and accuracy of ±0.06°), and its three-dimensional coordinate was calculated from a two-dimensional fluoroscopic image. A coordinate calculation formula was developed, with precision and accuracy assessed via computer simulations. Actual fluoroscopic tests included four aspects: accuracy under the same condition; accuracy under different X-ray tube height; reproducibility when changing X-ray tube height; and reproducibility when the flat panel was tilted and returned. ResultsThe theoretical measurement error indicated by the computer simulations was 0.0 ​± ​0.2° on the xy-plane and 0.0 ​± ​0.0° on the yz-plane. The actual experimental results showed that the horizontal plane tilt was measured to be −0.2 ​± ​0.1° tilt on the xy-plane and 0.3 ​± ​0.0° tilt on the yz-plane for the device used in this study. The F-test showed no significant differences between the computer simulations and the actual experiments. There were no significant differences between the four actual tests. ConclusionsThis method enables the horizontal plane to be defined and the tilt of an object to be measured in fluoroscopic kinematic analysis.

Effect of Temporal Decentration of Orthokeratologic Lens on Corneal Aberrations in Swept-source Optical Coherence Tomography

Purpose: This study used anterior segment swept-source optical coherence tomography (AS SS-OCT) to explore the effect of temporal decentration within the orthokeratologic lens treatment zone on corneal aberrations.Methods: After lens placement, AS SS-OCT was used to evaluate anterior, posterior, and total corneal astigmatism and the magnitudes of the individual 1st- to 4th-order aberrations of the anterior and entire corneal fields. Also, the 4th-to 7th-order root mean square (RMS), and the low- and high-ordered RMSs of both the anterior and entire corneal areas were recorded. We compared subjects lacking (the no decentration [ND] group) to those exhibiting (the temporal decentration [TD] group) temporal decentration.Results: In all, 61 eyes of 32 patients (44 eyes in the ND group and 17 in the TD group) were included. In the TD group, the average temporal decentration was 0.74 ± 0.15 mm. The baseline axial length, spherical equivalent, anterior mean corneal power, and anterior corneal astigmatism did no difference between the two groups. However, the TD group exhibited more anterior and total corneal horizontal tilts, and horizontal coma, than the ND group. That group also had less with-the-rule (WTR)/against-therule (ATR) astigmatism, elevated anterior and total corneal 5th-order RMS values, and greater low- and high-ordered RMS levels. However, despite these differences, the extent of myopia correction did not significantly differ between the groups.Conclusions: Although myopia reduction was not significantly compromised by temporal decentration of an orthokeratologic lens, the anterior and total corneal low- and high-ordered RMS values increased. In terms of individual aberrations, the low-ordered horizontal tilt and the high-ordered horizontal coma increased.

Experimental investigation of nonuniform PV soiling

Photovoltaic (PV) module soiling, i.e., the accumulation of dust on PV module surfaces, poses several challenges to PV system performance. Among these challenges, the nonuniform deposition of soiling across the module surface has received scarce attention. Soiling is directly associated with an overall performance loss, but can also potentially give rise to localised hotspots that can lead to long-term PV module failure. Therefore, addressing the issues arising from this nonuniformity is not only important for optimising energy production, but also for enhancing system reliability, and ensuring the long-term operation of relevant power generation systems. In this study, the impact of nonuniform soiling on PV performance is investigated experimentally by examining soil deposition on the upper surfaces of low-iron glass samples. Samples positioned at four different tilt angles were collected on a monthly basis over a one-year study period. Since the horizontal samples were found to represent the worst-case conditions, the most soiled sample at horizontal tilt was divided into four zones, each housing a single monocrystalline solar cell and examined further. The findings reveal that the soiled sample experiences an average transmittance deterioration of 13% relative to a clean sample, and a maximum (relative) spatial variation of 4% between the four zones. These optical losses affect the amount of sunlight received by the cells, resulting in a power deterioration of ∼6–7% per 5% drop in transmittance. The soiled sample experienced an average temperature rise of 2 °C, and an average power output (and efficiency) reduction of 30% relative to the clean sample, and a maximum (relative) spatial variation of 7% between the zones. The 30% average power loss measured in this nonuniform soiling case is more than double that which would be expected theoretically for a transmittance loss of 13% but from uniform soiling, so these results highlight the importance of addressing PV soiling for optimal PV performance, and of accounting for spatial soiling nonuniformity.

Improved nonlinear active disturbance rejection control based on hierarchical expected improvement for high-speed elevator horizontal vibration suppression

In this paper, an improved NADR control method based on hierarchical expected improvement (HEI) optimization is studied to suppress the horizontal vibration of high-speed elevator car under complex coupled disturbances to improve high-speed elevator ride comfort. First, a nonlinear 8-DOF dynamic model for the horizontal vibration of the high-speed elevator car is constructed. Then, a 4-level parallel NADR main control system based on the fal-function is designed to observe the total disturbance in real time, which can be quickly compensated by fuzzy sliding mode control. Meanwhile, the adaptive law is used to adjust fuzzy rules and sliding mode switching term coefficients to ensure the stability and adaptability of the control system. To address the problem of multiple bandwidth parameters and high sensitivity of the observer in the NADR control system, the comprehensive RMS experimental data fusion model based on hierarchical Gaussian process is constructed. With the goal of achieving the optimal value of comprehensive RMS, a hierarchical expectation improvement search strategy that balances exploratory and developmental aspects is studied to improve the optimization accuracy of bandwidth parameters. Finally, the results show that the proposed method can reduce the horizontal vibration acceleration and tilt angle acceleration of the car system by more than 68%.

Reliable Tilt-depth estimates based on the stable computation of the tilt angle using robust vertical derivatives

The Tilt-depth is a popular approach for determining depths of magnetic sources. As this method is based on the distance between contour levels of the tilt angle, it can lead to inaccurate depth estimates when the contour lines are distorted by the presence of noise. In this paper, we stabilize the Tilt-depth method based on the computation of stable vertical derivative obtained by the β-VDR method. The presented method is demonstrated on synthetic magnetic anomalies and real magnetic data from the Arabian Shield. The results obtained from the synthetic examples coincide well with the actual depths. These results proved the utility of the presented method in cases where the field is corrupted by noise. The real example shows that the presented method can provide valuable information on subsurface structures of the area where the Tilt-depth estimates are consistent with the result of the horizontal tilt angle. The findings show that the presented method is less sensitive to noise and can provide source edges and depths more clearly and with higher accuracy.

Analysis of legacy gravity data reveals sediment‐filled troughs buried under Flathead Valley, Montana, USA

AbstractShallow, dominantly silt‐ and clay‐filled erosional troughs in Quaternary sediments under the Flathead Valley (northwestern Montana, USA) are very likely to be hydraulic barriers limiting the horizontal flow of groundwater. Accurately mapping them is important because of increasing demand for groundwater. We used a legacy Bouguer gravity map measured in 1968. The directional derivatives of the map are computed, and the map was enhanced by implementing edge detection tools. We produced generalized derivative, maximum horizontal gradient, total gradient and tilt gradient maps through two‐dimensional Fourier transform analysis. These maps were remarkably successful in locating buried troughs in the northern and northwestern parts of the study area, closely matching locations determined previously from compiled borehole data. Our results also identify hitherto unknown extensions of troughs and indicate that some of the buried troughs may be connected.

Intraocular lens tilt and decentration in secondary ciliary sulcus implantation in paediatric eyes: A 3-year prospective study.

The purpose of this study was to compare the tilt and decentration of one-piece anti-vaulting haptic intraocular lenses (IOL) and three-piece C-loop haptic IOLs in paediatric eyes undergoing secondary IOL implantation into the ciliary sulcus. Paediatric aphakic patients receiving either one-piece anti-vaulting haptic or three-piece C-loop haptic IOL implants into the ciliary sulcus were enrolled in this prospective non-randomized interventional study and followed up for 3 years. IOL decentration and tilt were measured using Scheimpflug images. Preoperative and postoperative information, including demographic data and ocular biometric parameters and complications, were collected and analysed. Among 123 eyes of 79 paediatric patients, there were 72 eyes (58.54%) in the anti-vaulting haptic IOL group and 51 eyes (41.46%) in the C-loop haptic group. The anti-vaulting haptic IOL group had a lower incidence of clinically significant vertical IOL decentration than the C-loop haptic IOL group (23.88% vs. 43.14%, p = 0.037). No intergroup differences were observed in vertical or horizontal tilt or in horizontal decentration (all p > 0.05). One-piece anti-vaulting haptic IOL implantation was associated with a lower risk of clinically significant vertical decentration than three-piece C-loop haptic IOL implantation (odds ratio: 0.42, p = 0.037). There was a higher incidence of IOL dislocation in the C-loop haptic IOL group (15.22% vs. 4.17%, p = 0.046). In paediatric aphakic eyes undergoing secondary IOL implantation into the ciliary sulcus, one-piece anti-vaulting haptic IOLs can reduce the risk of clinically significant vertical IOL decentration compared with three-piece C-loop haptic IOLs and may favour long-term IOL positional stability.

Comparison of intraocular lens tilt after capsular sutured scleral fixation with capsular segments versus uneventful cataract surgery.

To evaluate and compare intraocular lens (IOL) tilt between uneventful phacoemulsification with in-the-bag IOL implantation and sutured scleral fixation (SSF) of the lens bag with a capsular tension segment (type 6 D / Morcher) using a Sheimpflug camera. Clinical Practice, Hospital. Barcelona and A Coruña, Spain. Retrospective, comparative multicenter study. IOL tilt was compared between patients who underwent sutured scleral fixation with a capsular tension segment in a single eye (SSF group, n = 15) with patients who underwent uneventful IOL implantation (control group, n = 12) that were matched by biometric measurements. Post-operative refractive accuracy of biometric formulas by means of mean absolute error (MAE) was also reported. All patients underwent a general ophthalmic evaluation, anterior segment photography, and postoperative optical biometry (Zeiss IOLMaster® 500). In addition, IOL tilt was measured with a Scheimpflug camera (Pentacam R, Oculus Optikgerate Gmbh). Mean vertical tilt was similar in both groups (2.20+/-2.47° SSF vs 1.97 +/- 1.79° control; p = 0.836) but mean horizontal tilt tended to higher values in the SSF series (2.09 +/- 2.74° vs 0.94 +/- 1.17°; p = 0.139). Considering post-operative refractive error in diopters by MAE calculations, there was an underestimation of IOL power in the SSF group which was only statistically significant for Barrett Universal II (1.07 vs 0.32; p = 0.028) and Hill-RBF (0.95 vs 0.26; p = 0.024) formulas, but not for SRK/T (0.99 vs 0.42; p = 0.285) and Kane (0.96 vs 0.33; p = 0.083). Sutured scleral fixation of capsular tension segments in the presence of zonular instability does not seem to induce clinically significant IOL tilt compared to uneventful cataract extraction cases.

Outcomes of Secondary Intracapsular Intraocular Lens Implantation in Patients following Rhegmatogenous Retinal Detachment.

This study reports the outcomes of a secondary IOL implantation technique in patients that suffered from rhegmatogenous retinal detachment combined with a cataract, which included reopening the capsular bag, enabling secondary intracapsular intraocular lens (IOL) implantation. We included consecutive cases with rhegmatogenous retinal detachment (RRD) treated with vitrectomy and silicone oil tamponade, and subsequent secondary IOL implantation during silicone oil removal between September 2019 and June 2022. Demographics, pre- and postoperative clinical data, and complications were collected. Visual and refractive outcomes and IOL position were evaluated. Thirty eyes were included and followed up for a mean of 24.2 ± 5.06 months. Compared with the preoperative values, no significant changes were observed in the intraocular pressure (p = 0.170) and endothelial cell density (p = 0.336); however, the best-corrected visual acuity (Snellen: 20/83 vs. 20/38; logMAR: 0.66 ± 0.23 vs. 0.37 ± 0.32; p < 0.001) and spherical equivalent (p < 0.001) improved significantly. The mean prediction error (ME) was -0.45 ± 0.68 D (-1.9-0.54 D), and the mean absolute prediction error (MAE) was 0.62 ± 0.52 D (0.01-1.9 D). The macula-on subgroup demonstrated significantly better refractive outcomes than the macula-off subgroup (ME, p = 0.046; MAE, p = 0.008). The IOL was well positioned, with a mean horizontal and vertical tilt and decentration of 0.53 ± 0.49° and 0.21 ± 0.16 mm, and 0.54 ± 0.45° and 0.22 ± 0.16 mm, respectively. Secondary intracapsular IOL implantation provided a good and stable IOL position and satisfactory refractive outcomes, and is a feasible treatment option for patients with RRD.

Delineation of geological structures of Arta geothermal prospect in Djibouti based on the gravity data analysis and interpretation

The Arta geothermal prospect is located in the southern part of the Gulf of Tadjoura, 45 km west of Djibouti city. This study uses 398 gravity data stations collected by the Djiboutian Office for Geothermal Energy Development (ODDEG) from February to May 2018. The geothermal activity of the Arta area is revealed by surface thermal manifestations, such as near-boiling fumaroles (98 °C). This study aims to delineate the subsurface geological structures responsible for surface geothermal manifestations and define the depth and geometry of the geothermal reservoir in the study area. A Complete Bouguer anomaly was obtained using a Bouguer density of 2.55 g/cm3, derived as an average density from the F-H, G-H and CVUR methods. A regional and residual anomaly trend separation method was applied to focus on the structures of interest in the study area, and a residual Bouguer anomaly map was obtained. Edge detection filters, including Horizontal Derivatives (HD) and an Improved Normalized Horizontal tilt angle (INH), were used to examine the gravity data for edge identification. The density was then modelled in three-dimensional (3-D), utilizing the VOXI Earth Modeling Tool performed in Geosoft Oasis Montaj. The model was constrained using estimated lower (-0.35 g/cm3) and upper (0.65 g/cm3) bound density values from the expected density values of the local geology. The Bouguer and residual anomaly maps show a high-density body in the central part, surrounded by low-anomaly structures. The high-density body is interpreted as an intrusive body covering the basement of the study area. The anomalies imaged from HD and INH indicate a significant number of high gradient anomalies trending N-S, NE-SW, and NW-SE, corresponding to the trend of the geological structures of the Arta geothermal prospect. These high-gradient anomalies can be interpreted as faults, contact zones, or geological boundaries. The 3-D model imaged a high-density anomaly trending N-S in the central part at 2 and 3 km below sea level with a volume of about 126 km3 and an average block density of 2.66 g/cm3, interpreted as magma intrusion or intrusive volcanic rocks. The 3-D vertical cross-sections revealed that the intrusion is visible at depth and that some intrusions could be seen at the surface and near surface. The findings of this gravity study will contribute to the overall and future geothermal exploration and development of the Arta geothermal prospect.

Gravity patterns and crustal architecture of the South-Central Indian Ridge at 22°-17°S: Evidence for the asymmetric ridge accretion

The present study examines the gravity-derived structural fabric and crustal structure beneath the southern portion of the Central Indian Ridge at 22°-17°S. We examined the structures using enhanced edge detection techniques like gradient amplitude of the vertical derivative (HGVD), improved horizontal tilt angle (ITDX), gradient amplitude of the NTilt (HGNTilt) and the fast sigmoid function (FSED) on synthetic examples and the gravity data of the study region. The gravity-derived lineaments describes the lineaments that are parallel to fracture zones trending in ENE-WSW, parallel to segments/major ridge axis, near circular lineaments probably depicting ascending magma sources. We estimated the depth to the gravity-derived lineaments using the tilt_depth technique, which reveals the presence of lineaments with shallow source depth range at 2.5–7 km. The south-Central Indian Ridge is characterized by numerous lineaments with random depths that shows variable spreading rates and continuous ridge jumps. The major lineament depths are rooted into the lower crust beneath the major axis and the upper mantle in the region away from it. In addition, gravity inversion of low-pass filtered Bouguer anomaly data is used to estimate the crustal thickness. The gravity inversion shows that the Moho depth varies from 5 to 14.5 km, which shows thicker crust along the principal ridge axis and thinner in the surrounding regions. The structural fabric in combination with the crustal thickness, depth of the lineaments, age of the ridge crust, earthquake data suggests discrete minor/local ridge jumps along the major ridge axis and asymmetric accretion along the ridge axis.

Comprehensive approach for capsular bag fixation in subluxated crystalline lens: preserving the anterior/posterior anatomical segment barrier.

To report the intraoperative performance and postoperative outcomes of crystalline lens removal and in-the-bag intraocular lens (IOL) implantation with scleral-bag fixation by means of capsular tension segments (CTSs) and a capsular tension ring (CTR) in patients with a subluxated lens. Department of Ophthalmology, Shaare-Zedek Medical Center, Jerusalem, Israel. Retrospective, consecutive case series. This study included patients with subluxated crystalline lens who underwent lensectomy or cataract extraction using an anterior chamber maintainer (ACM), a CTR, transscleral capsular-bag fixation by polytetrafluoroethylene suture with 2 CTSs, and in-the-bag IOL implantation. Outcome measures included intra- and postoperative complications, corrected distance visual acuity (CDVA), target and postoperative refraction, and IOL tilt. 17 eyes (9 patients) were included, with a mean follow-up of 22.06 ± 14.88 months. There was a significant improvement in mean logMAR CDVA ( P < .001), with 15 eyes (88.24%) achieving a Snellen CDVA of 20/30 or better and all eyes achieving 20/40 or better. The mean refractive spherical-equivalent prediction error was 0.07 ± 1.10 diopters (D), with 10 (58.82%) and 15 (88.24%) of eyes within ±0.50 D and 1.00 D, respectively, from the intended refraction. The mean horizontal and vertical tilts were 1.9 ± 2.6 degrees and 2.6 ± 2.1 degrees, respectively. No complications were observed except for 1 case of an intraoperative posterior-capsular tear. A comprehensive surgical approach for scleral-bag fixation that combines the use of an ACM, CTR, polytetrafluoroethylene sutures, 2 CTSs with in-the-bag IOL implantation, offers an effective strategy for achieving favorable visual outcomes and a low incidence of complications in patients with subluxated crystalline lenses.

A Global Perspective on the Upper Branch of the Hadley Cell

Abstract The global perspective presented here is built on earlier papers discussing the dynamics of the upper branch of the Hadley cell in the two solsticial seasons. The role of the tropics is made explicit in a conceptual model that is presented and evaluated. The fluctuation of deep tropical convection in longitude and time is seen as crucial. The filamentary outflows from such convective events move westward and across the equator deep into the winter hemisphere. The horizontal tilt of the cross-equatorial flow implies a significant upper-tropospheric flux of westerly momentum from the winter tropics to the summer hemisphere. These properties are related to the cross-equatorial propagation of wave activity triggered by deep tropical convection in the summer hemisphere. The filaments carry with them near-equatorial values of absolute vorticity and potential vorticity. After turning anticyclonically, some filaments move eastward and poleward to the equatorial edge of the winter subtropical jet. There is strong evidence they can interact with the eddies on this jet and enhance their poleward westerly momentum flux. In the global perspective, tropical and extratropical systems and the interaction between them are all important for the dynamics of the upper branch of the Hadley cell. significance statement The Hadley cell is the large-scale overturning in the atmosphere with air in the upper troposphere moving from the equatorial region to near 30° in the winter hemisphere. In the standard view it is midlatitude weather systems that are responsible for removing angular momentum from this upper branch of the Hadley cell. Here it is proposed that tropical systems and their interaction with the midlatitude systems are also important. Insight into the role of the tropics in the dynamics of the Hadley cell can be obtained by considering it as the sum of many events of active deep convection occurring in different longitudes and at different times.

Dynamics of droplets entering ultrasonic standing wave field at different angles

We, herein, present dynamic behaviors of droplets entering an ultrasonic standing wave field (19 800 Hz) at different angles. In experiments, droplets’ motion is recorded by using a high-speed camera, and an in-house Python program is used to obtain droplet positions and morphological characteristics as functions of time. The experimental results indicate that when the sound intensity is lower than the instability intensity and higher than the levitation intensity, the vertically falling droplet will oscillate up and down based on the equilibrium position. Although the oscillation amplitude decays from 0.52Tl to 0.01Tl (Tl = λ/2, λ is the wavelength) under the action of viscous resistance, the oscillation frequency of the droplet remains unchanged. Meanwhile, as the droplet’s position oscillates, the acoustic radiation force on the droplet also periodically fluctuates, resulting in the acoustically forced oscillation of the droplet shape. In addition, when the droplet enters the sound field with a horizontal tilt angle θ of 15°, it undergoes a V-shaped translational motion, first descending and then ascending. As the sound pressure amplitude increases, the rebound position of the droplet advances. When the sound pressure amplitude reaches the instability value (7900 Pa), the droplet undergoes right-hand and left-hand disintegration during its descent and ascent, respectively. This instability is due to the acoustic radiation pressure distribution and the droplet’s V-shaped trajectory. This work comprehensively discussed the complex motion of moving droplets in the acoustic standing wave field, which may inspire revealing the spray motion in the liquid engine with high-intensity resonance.

An experimental investigation on the influence of condenser bypass area for the transient and steady-state heat-transfer performance of heat pipes

Fundamentally, an effective method for improving the performance of transient and steady-state heat transfer is reducing the flow resistance at the phase-change interface based on the counter flow of vapor and liquid within a typical heat pipe. The flow resistance at such an interface is proportional to the volume flow rates of liquid and vapor. Therefore, the flow resistance at the interface can be reduced by limiting the mass flow rate of vapor or liquid. In this study, experiments were performed on a liquid bypass to improve the steady-state thermal performance of heat pipes. A separate bypass tube allowed some liquid to be subcooled in the condenser to bypass the evaporator without passing through the heat pipe. Three liquid-bypass ports were designed and fabricated in a condenser to experimentally investigate the influence of the bypass port area on the thermal performance of the heat pipe under steady-state operation. An on/off valve was attached to each bypass tube port in the condenser to control the bypass flow rate. The results showed that the thermal resistance, an evaluation index of the performance of steady-state heat transfer, generally decreased with an increase in the bypass port area of the condenser. The thermal resistance of a heat pipe with a horizontal tilt angle and one at an inclination angle of 50° decreased by up to 25.5% and 51.6%, respectively.