Rectangular Plane Research Articles

Analytical solutions for steady groundwater flow through aquifer folds and faults

Deformations of the earth’s crust create tortuous paths for groundwater flow, altering pressure distributions and flow lines. A solution for steady groundwater flow through a deformed aquifer is derived by applying the singular point method using a rectangular reference plane. The singular point method is used to develop conformal mappings with complex geometries using basic principles of groundwater mechanics including superposition, the method of images, and stagnation point analysis. The derived solution contains three parameters that can be chosen to simulate flow through a variety of deformed aquifers, including flow through a normal fault with a 90∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {90}^\\circ $$\\end{document} dip, flow through a fold, and flow through a relay ramp.

Design discharge estimation for small urban districts – an analytical approach

ABSTRACT This paper presents a straightforward design discharge estimation procedure for small urban districts. In this approach, the configuration of the small urban district was simplified into either a rectangular porous overland plane or a V-shaped porous overland model. The Horton equation was used to estimate the infiltration on the overland planes, and the kinematic-wave approximation was applied for runoff simulations. In deriving the runoff equation, the Darcy–Weisbach coefficient was adopted to account for the influences of spatially various flow depths on overland flow resistance. The theoretical derivations were applied to a series of cases and verified by numerical models to demonstrate the applicability of the proposed method. The results showed that the design discharges obtained from the analytical equations are close to those simulated by the numerical model. The analysis procedure developed herein can provide a convenient way for engineers to conduct urban sewer designs.

The 2024 Mw 7.0 Wushi Earthquake in Southern Tianshan Convergent Zone: Finite-Fault Model for the Coseismic Rupture and Aftershock

Abstract On 22 January 2024, an Mw 7.0 earthquake struck the oblique thrust Maidan fault (MDF) at the boundary between the Southern Tianshan and Tarim basin, making it the largest earthquake on the fault in the last 100 yr. Here, we use Interferometric Synthetic Aperture Radar (InSAR) to retrieve coseismic and aftershock deformation caused by the earthquake and then constrain fault geometry and slip distribution. Line-of-sight InSAR observations revealed a coseismic deformation area of 70 km × 60 km with a maximum value of ∼0.8 m and also captured the deformation from the aftershock event seven days after the mainshock. Our preferred two-segment coseismic fault model ruptures the MDF locked segment and deeper regions, exhibiting a homogeneous elliptical rupture with a maximum slip of ∼2.7 m on a rectangular plane with a dip angle of ∼60°, a length of ∼55 km, and a depth between 5 and 20 km. The aftershock formed a rupture plane of 10×8 km2 with the maximum slip of ∼0.3 m, causing slip in the shallow area of the fault where the coseismic ruptures were smaller, and supplementarily released the stress in the shallow part of the fault. The strong earthquake (Mw 7) return period on MDF inferred from the interseismic slip rate is 170–200 yr. Oblique thrust slip revealed by the slip distribution model is the result of long-term absorption of oblique convergence strain in the Southern Tianshan by the MDF and then concentrated release. The 2024 event resulted in a 60 km unruptured segment on the MDF being in a stress-triggering zone, increasing the potential seismic hazard, in contrast to the delayed seismicities on 100 km region of the southern Kalping fault (KPF).

Low-profile robust circularly polarized textile patch antenna for WBAN and ISM applications

In this research, a conformal circularly polarized (CP) antenna has been developed employing polyester textile as its substrate material. The proposed antenna configuration demonstrates its efficacy across multiple frequency bands—specifically 3 GHz and 4.5 GHz of WBAN and 5.8 GHz of ISM radio bands. The antenna’s distinctive design is developed on a rectangular plane as its primary radiating component, with a ground structure ingeniously arranged counter-positioning to the antenna’s patch. Electrical conductivity was widely achieved by employing adhesive copper and silver tape, conductive fabric, stitching conductive threads and copper paint, conventionally applied through brush painting techniques. The copper paint fabrication methodology has been chosen for its ability to confer conformability upon the antenna while minimizing its dimensions, ensuring lightweight attributes, and endowing it with remarkable resilience to environmental factors while preserving its optimal radiating performance. The CP polyester antenna showcases noteworthy peak gains: 3.91 dBi at 3 GHz, 5.86 dBi at 4.5 GHz and 6.62 dBi at 5.8 GHz (ISM). These gains highlight the antenna’s ability to efficiently capture and transmit signals within the aforementioned frequency bands, affirming its potential for robust wireless communication.

A novel asymmetric antipodal Vivaldi MIMO antenna

This communication describes the development and assessment of the genuine Antipodal Vivaldi MIMO antenna operating in the ultra-wideband spectrum. FR4 dielectric material, which is widely used in antenna designs and has characteristic features, is selected and used as a dielectric. The single antenna component has two asymmetric flares obtained with different parameters, and it also has a rectangular ground plane combined with a bottom flare. In the MIMO configuration, the single-antenna is built in a rotationally orthogonal way to generate a four-port system with the dimensions of 45 × 45 × 1 mm3. The vertical and horizontal stubs are added to the ground flare to obtain a common ground structure and increase the performance of the novel antenna design. It has a bandwidth of approximately 9 GHz, which starts from 2.85 GHz and ends at 11.8 GHz. The antenna has reasonable gain values and a high isolation value between the elements in the operation range. In this context, it is foreseen that the developed structure can be utilized in distinct multiport UWB applications.

Complex fault system associated with the Molucca Sea Divergent double subduction zone revealed by the 2019 Mw 6.9 and Mw 7.1 Earthquakes

GNSS (Global Navigation Satellite System) data in northern Sulawesi and western Halmahera reveals a pattern of coseismic displacement that was caused by the 7 July 2019 (Mw 6.9) and 14 November 2019 (Mw 7.1) Molucca Sea earthquakes. The coseismic slip of these earthquakes are obtained via inversion on rectangular fault planes of surface GNSS coseismic deformation offsets. The 7 July 2019 earthquake ruptured on an east-dipping fault with a maximum slip of ∼35 cm located at ∼4 km depth and ∼ 100 km north-west of the epicenter. The 14 November 2019 earthquake also ruptured on an east-dipping fault, which has a maximum slip of ∼64 cm located at ∼22 km depth and ∼ 20 km south-west of the epicenter. The coseismic slip distribution of the 14 November earthquake is spatially aligned to that of an earthquake of similar magnitude that took place on 15 November 2014 in the same region. This observation points to the possibility of synchronization, thus raising the prospect of a future earthquake exceeding magnitude 7. If the stress was completely released during the 2014 event, it would have been necessary to reload that portion of the fault at a rate significantly larger than the observed convergence rate of ∼5.8 cm/yr. This suggests that partial ruptures are likely controlling the recurrence time of large earthquakes in the region.

Synthesis of sparse rectangular planar arrays with weight function and improved grey wolf optimization algorithm

AbstractThe present article proposes a novel hybrid approach for addressing the synthesis problem of rectangular planar arrays under multiple constraints, through joint optimization of the weight function and the improved grey wolf optimization (IGWO) algorithm. Firstly, the grey wolf optimization (GWO) algorithm is improved by using tent chaotic mapping, nonlinear convergence factor, dominant wolf dynamic belief strategy, and opposition‐based learning strategy to increase the population diversity and the ability to jump out of the local optimum. Secondly, the array elements are weighted using the weight function to generate the position distribution matrix, which reduces the thinned matrix optimization time and improves the optimization efficiency. Finally, the position distribution matrix is used to generate the thinned array, and the IGWO algorithm is applied to perform the sparse optimization with multiple constraints. The effectiveness of the method is verified through numerical simulation and full‐wave simulation experiments, demonstrating its capability to enhance array antenna performance and reduce peak sidelobe level (PSLL). These experimental results hold significant engineering implications and provide valuable references for addressing the array distribution problem under multiple constraints.

Multimodal Resonances of a Rectangular Planar Dielectric Elastomer Actuator and Its Application in a Robot with Soft Bristles.

Inspired by the fact that flying insects improve their power conversion efficiency through resonance, many soft robots driven by dielectric elastomer actuators (DEAs) have achieved optimal performance via first-order modal resonance. Besides first-order resonance, DEAs contribute to multiple innovative functions such as pumps that can make sounds when using multimodal resonances. This study presents the multimodal resonance of a rectangular planar DEA (RPDEA) with a central mass bias. Using a combination of experiments and finite element modeling (FEM), it was discerned that under a prestretch of 1.0 × 1.1, the first-, second-, and third-order resonances corresponded to vertical vibration, rotation along the long axis, and rotation along the short axis, respectively. In first-order resonance, superharmonic, harmonic, and subharmonic responses were activated, while only harmonic and subharmonic responses were observed in the second- and third-order resonances. Further investigations revealed that prestretching tended to inhibit third-order resonance but could elevate the resonance frequencies of the first and second orders. Conveniently, both the experimental and FEM results showed that the frequencies and amplitudes of the multimodal resonances could be tuned by adjusting the amplitudes of the excitation signals, referring to the direct current (DC) amplitude and alternating current (AC) amplitude, respectively. Moreover, instead of linear vibration, we found another novel approach that used rotation vibration to drive a robot with soft bristles via hopping locomotion, showcasing a higher speed compared to the first-order resonance in our robot.

Dual-Wideband Rectenna for RF Energy Harvesting from 5G and WIMAX

ABSTRACT A dual wideband rectenna has been built to effectively capture radio frequency (RF) energy from 3.3 GHz to 3.7 GHz and 4 GHz to 6.3 GHz. An antenna with a rhombus form is created, which includes a rhombus slot and two rectangular strip ground planes. The planned antenna has been planned specifically to receive signals between the 3.5 GHz and 5.5 GHz frequency ranges. The highest conversion efficiency (CE) attained at 3.5 GHz and 5.5 GHz, without an impedance matching network (IMN), are 32.5% and 33%, respectively. These values are relatively low. To improve conversion efficiency, a two-line pi-impedance matching network is used, which includes DC combining. The rectenna is being evaluated for the specified frequency ranges. The highest simulated CE attained at 3.5 GHz was 81.5%, but the measured CE was 80% when the IPL was 3 dBm. The highest simulated CE at 5.5 GHz was 66.3%, but the measured CE was 65% when the IPL was 8 dBm. The proposed work is on the extraction of RF energy from the widely used 5 G and WiMax frequency bands.

Computationally efficient Watershed-Scale hydrological Modeling: Integrating HYDRUS-1D and KINEROS2 for coupled Surface-Subsurface analysis

Watershed flow processes consist of partitioning, movement, storage, and redistribution of water fluxes in space and time. However, the integrated modeling of these processes is challenging due to computational burden, extensive data requirements, and/or reliance on simplifying assumptions. This study introduces a novel and computationally efficient modeling framework that leverages two state-of-the-art process-based models: HYDRUS-1D (H1D) for unsaturated flow and KINEROS2 (K2) for overland flow. The framework extends a hillslope-scale coupled H1D-K2 model to simulate watershed-scale processes, where H1D replaces the three-parameter Parlange’s infiltration equation in the event-based K2 model. Boundary condition switching is employed to account for surface ponding and water exchange between the two model domains. The structure of the coupled watershed-scale H1D-K2 model consists of a cascade of connected rectangular planes, channel elements, and 1D soil profiles to simulate 1D overland flow, infiltration, unsaturated zone flow, and recharge. Computational efficiency relative to HYDRUS-2D is achieved through a dynamic time-stepping approach and dimensionality reduction. The watershed scale model improved the computational time by 14.3% and 47% compared to the corresponding Hillslope scale H1D-K2 and HYDRUS-2D, respectively. The performance and efficiency of the new watershed model are demonstrated using benchmark watershed and/or hillslope simulations. Calibrated hydrographs and water balance components using Walnut Gulch Experimental Watershed data, showed excellent agreement with observed data with a Nash-Sutcliffe coefficient (NSC) greator than 0.8 and Pearson correlation coefficient (R2) greater than 0.92.

A Novel Folding Wireless Charging Station Design for Drones

Unmanned aerial vehicles (UAV) have been used in many fields nowadays. In long-term applications, batteries need to be constantly changed by someone due to short battery life. This problem is eliminated with wireless power transfer (WPT). A reliable, effective, and autonomous solution is offered using wireless charging. The most suitable wireless charging technique for UAVs is inductive power transfer (IPT). In this paper, a novel foldable coil and charge station design is proposed for the wireless charging of UAVs. IPT is provided by receiver and transmitter coils placed on the drone legs and the charging station, respectively. Receiver coils are placed on both legs of the UAV in a light and balanced manner to avoid creating imbalance and weight on the UAV. Receiver coils are designed as vertical rectangular planar spirals. A transmitter coil consists of three rectangular planar spiral coils with two movable edge windings and a fixed middle winding. The transmitter’s folding windings provide both alignments for the UAV during landing and increase the magnetic coupling. A folding wireless charge system of the UAV is designed for 100 W output power at a 138.1 kHz frequency. The misalignment tolerance of the proposed design in the vertical axis is examined. The design’s magnetic flux density distribution is analysed. As an experimental result of the study, 97.66% efficiency was reached in the aligned condition. Also, over 85.48% efficiency was achieved for up to 10 cm of vertical alignment misalignment.

MIRACLE—a microphone array impulse response dataset for acoustic learning

This work introduces a large dataset comprising impulse responses of spatially distributed sources within a plane parallel to a planar microphone array. The dataset, named MIRACLE, encompasses 856,128 single-channel impulse responses and includes four different measurement scenarios. Three measurement scenarios were conducted under anechoic conditions. The fourth scenario includes an additional specular reflection from a reflective panel. The source positions were obtained by uniformly discretizing a rectangular source plane parallel to the microphone for each scenario. The dataset contains three scenarios with a spatial resolution of 23mm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$23\\,\ extrm{mm}$$\\end{document} at two different source-plane-to-array distances, as well as a scenario with a resolution of 5mm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$5\\,\ extrm{mm}$$\\end{document} for the shorter distance. In contrast to existing room impulse response datasets, the accuracy of the provided source location labels is assessed and additional metadata, such as the directivity of the loudspeaker used for excitation, is provided. The MIRACLE dataset can be used as a benchmark for data-driven modelling and interpolation methods as well as for various acoustic machine learning tasks, such as source separation, localization, and characterization. Two timely applications of the dataset are presented in this work: the generation of microphone array data for data-driven source localization and characterization tasks and data-driven model order reduction.

Fluid–structure interaction of a marine rudder at incidence in the wake of a propeller

The structural response of a rudder in the wake of a marine propeller is investigated by one-way fluid–structure interaction approach. The unsteady pressure field gathered by detached eddy simulations is provided to a structural solver for the computation of deformations and stresses of the rudder. The study compares the structural response of the rudder at neutral and two equal and opposite rotations, which are representative of design conditions in straight motion and maneuvering conditions that are experienced under the action of the autopilot for course control or weak maneuvering. The analysis sheds light on the different structural behavior at the two opposite rotation angles, caused by asymmetrical variation along the span of the rudder of the angle of attack induced by the propeller slipstream, by considering the different role played by the tip and hub vortical systems. The test case consists of a rudder with a rectangular plane area and National Advisory Committee for Aeronautics 0015 sectional profile located past the E779A propeller. The propeller operates at low loading conditions, and the rudder is set at incidence δ=0∘,±4∘. The study shows that the response of the rudder is driven by flap and torsion and is asymmetric for the two and opposite rotations. The mean deformation and vibratory response are magnified for δ=−4∘ by at least 70% and 20% for the lateral and edgewise deflections, respectively, with respect to the opposite rudder incidence. In general, the excitation generated by the tip vortex is stronger than that of the hub vortex. In the most critical condition, at δ=−4∘, the excitation associated with the tip vortex is nearly double that of the hub vortex.

Symmetric Quantum Inequalities on Finite Rectangular Plane

Finding the range of coordinated convex functions is yet another application for the symmetric Hermite–Hadamard inequality. For any two-dimensional interval [a0,a1]×[c0,c1]⊆ℜ2, we introduce the notion of partial qθ-, qϕ-, and qθqϕ-symmetric derivatives and a qθqϕ-symmetric integral. Moreover, we will construct the qθqϕ-symmetric Hölder’s inequality, the symmetric quantum Hermite–Hadamard inequality for the function of two variables in a rectangular plane, and address some of its related applications.

Dating mortars and bricks of Santalla de Bóveda Monument (Lugo, NW Spain)

Santalla de Bóveda Monument (Lugo, NW Spain) is a small semi-buried building, under the Bóveda parish church, built in the 18th century, with an apsidal quadrangular floor plan, which was divided into three naves, a small vaulted apse and a rectangular floor plan vaulted, where paintings depicting birds and plant elements have been well preserved. The monument has aroused great interest since its discovery, but its chronology and functionality has always been the subject of controversy. Several hypotheses have suggested that the monument was built in the Roman period and some others around the 5h, 8th or 9th century AD. However, any direct evidence or absolute age has been provided until today. The stratigraphic analysis of the building suggests five constructive phases. Bricks and mortars of all phases were sampling to perform absolute dating techniques and to get a precise and accurate chronology. Radiocarbon dating of mortars and Optically Stimulated Luminescence (OSL) dating of bricks and mortars have been used to this purpose. A total of 34 samples were taken, being 20 used for luminescence (mortars and quartz aggregates) and 15 used for 14C ages (charcoal fragments of lime mortars). 5 brick samples were also dated by Thermoluminescence (TL). The obtained ages have allowed, for the first time, stablishing an accurate and precise chronology being the first phase assigned to the 4th Century AD. Alterations of the building and the vault paintings were performed in the early 7th century, while the construction of the second floor and occasional repairs were performed during the 10th-12th centuries.

UWB-MIMO 4-Port Fractal Antenna with Reduced Mutual Coupling

Abstract: UWB MIMO antenna loaded structure Mutual coupling between the four radiating elements is obtained to be less than - 25 db. The patterns of radiation are stable over the operating range and a peak gain of 4.5 dB is obtained at 7.5GHz and Return loss is obtained less than 10dB. Simulation is conducted using HFSS simulation tool and printed on a 30 X 30 X 1.6 mm3 FR4 material. 4 linear SRR structures are used between adjacent elements to ensure good isolation. MIMO antenna with grounded stubs and fractal geometry are used to improve isolation and to achieve wide band phenomena. UWB-MIMO antenna using to achieve better isolation. The UWB MIMO 4-port fractal antenna combines the characteristics of ultra-wideband operation, multiple input multiple output capability, four-port configuration for simultaneous data streams, and a fractal antenna design for wide bandwidth and compact size. This makes it suitable for high-speed, reliable communication in applications requiring UWB technology, such as high-speed data transfer, localization, and radar systems. By integrating a copper rectangular plane between ports, interference and crosstalk are minimized, enhancing the antenna's capability to handle multiple input and output signals efficiently. This innovative design approach not only improves isolation but also contributes to the antenna's overall effectiveness in various communication applications.

Chiral plasmonic metasurface assembled by DNA origami

Chiral materials are essential to perceive photonic devices that control the helicity of light. However, the chirality of natural materials is rather weak, and relatively thick films are needed for noticeable effects. To overcome this limitation, artificial photonic materials were suggested to affect the chiral response in a much more substantial manner. Ideally, a single layer of such a material, a metasurface, should already be sufficient. While various structures fabricated with top-down nanofabrication technologies have already been reported, here we propose to utilize scaffolded DNA origami technology, a scalable bottom-up approach for metamolecule production, to fabricate a chiral metasurface. We introduce a chiral plasmonic metamolecule in the shape of a tripod and simulate its optical properties. By fixing the metamolecule to a rectangular planar origami, the tripods can be assembled into a 2D DNA origami crystal that forms a chiral metasurface. We simulate the optical properties but also fabricate selected devices to assess the experimental feasibility of the suggested approach critically.

Analysis of doubly curved laminated composite shells using hybrid-Trefftz finite element model based on a high order shear deformation theory

Static analysis of doubly curved laminated composite shells with rectangular plan form has been carried out using a novel hybrid Trefftz finite element (HTFE) model. A typical higher order shear deformation theory (HSDT) has been used for describing the kinematics of deformations delineating both internal and auxiliary displacement fields. This HSDT allows to derive the system of governing partial differential equations of the single layer equivalent to the element domain. The characteristic functions forming the exact solutions of these homogenous governing equilibrium equations are used as the Trefftz functions. A key aspect of our HTFE strategy is its efficiency in bypassing the use of particular solution of the governing equations. Validation against the exact solutions reveals the precision of this novel HTFE model. The versatility of the Trefftz functions allows them to accommodate a spectrum of geometric configurations, ranging from standard to complex polygonal HTFE designs. The HTFE model for the doubly curved composite shells employing the HSDT marks a significant advancement in the analysis of doubly curved spherical, paraboloid and hyperboloid cross-ply and antisymmetric angle-ply shells.

Wind effects on rectangular plan building located in a hilly terrain: A wind tunnel investigation

Wind effects on rectangular plan building located in a hilly terrain: A wind tunnel investigation

Seismic retrofitting of an existing hospital with external steel brace

Earthquakes may cause serious damage to buildings and result in heavy losses to society, therefore, it is necessary to enhance the seismic capacity of existing buildings via structural retrofitting. The traditional retrofitting approaches are based on the component-level, but their improvement effect for the overall structure is not obvious. Until now, the seismic retrofitting technology can be generally divided into three types. The first is strength-improving type, the second is ductility-improving type, and the third is seismic dissipation/isolation type. Commonly a combination of these three types is used in retrofitting solutions. Most of them are focused on member based or component-level improvements of strength and/or ductility applied to poorly reinforced concrete walls or columns and masonry walls. Meanwhile, the weak element of the existing structure can be strengthened by external sub-structures as steel frames to make the overall structural capacity or stiffness more uniform. In addition, because the construction is an external operation, it can achieve non-disturbing retrofitting without affecting the normal use of the inner structure, which is of great practical significance and social benefits for lifeline projects such as schools and hospitals that cannot be interrupted. In the present case study, the efficiency of a seismic retrofitting with external steel frame of the university hospital Zurich (USZ) will be discussed. The original 3-story reinforced concrete building with a rectangular floor plan of 44m x 24m was built in 1966. Subsequently, in 1970, the building was extended by 4 floors with a composite steel structure. On the roof floor there is a helipad for emergencies. The stiffening steel structure was connected to the building with post-installed anchors. The first results of a response spectrum analysis showed major deficiencies in terms of horizontal and torsional stiffness, so that a strengthening measure became necessary. The results were verified by means of a push-over analysis, which showed that the measure applied was very effective. Finally, the structural design and the connection details to the existing concrete structure are shown.