Cross Shape Research Articles

New insight into synergistic interaction between the backbone or side chain of xanthan gum and the backbone of Gleditsia sinensis polysaccharide

In this study, the synergistic effect and weak gel mechanism of XG and Gleditsia sinensis polysaccharide (GSP) in different ratios were studied through the rheological properties, microstructure and molecular simulation based on density functional theory (DFT). The results of rheological properties showed that the mixtures formed a weak gel at the concentration of 0.5 % (w/v), with the synergistic impact peaking at a XG/GSP ratio of 3:7. Weak gels produced by XG and GSP had the intersection of G' and G" within the temperature sweep range, and the largest change in the G' slope at a XG/GSP ratio of 3:7. By calculating the interaction energy, it was found that the backbone of XG was more likely to interact with the backbone of GSP. Furthermore, the XG mainchain intersected with the backbone of GSP in a cross shape (“X” shape). As a result, this paper proposed a possible mechanism for the formation of the XG/GSP weak gel, with XG as the main chain and GSP as the grid point, and the main interaction type being hydrogen bonding, with the van der Waals force also involved. The results provide new insight for designing and producing physical gels with specific interactions in food industry.

Mechanism of pre-tension on the impact response of plain weave fabric: Experimental and numerical investigation

The fabrics made of high strength and toughness fibers are increasingly used in the structural and individual protection. The research on energy dissipation mechanism and the improvement methods for improving energy dissipation of the fabric under impact, as well as the change of ballistic limit velocity under pre-stress, is relatively mature. However, the transmission mode and velocity of transverse wave in the fabric, as well as the method of accurate finite element simulation is still lacking. In this paper, the transverse impact response of ultra high molecular weight polyethylene (UHMWPE) fabric subjected to fragment impact is studied experimentally and numerically. A novel biaxial pre-tension fixture was developed, and fragment impact test of the fabric in pre-tension state was realized using a gas gun. The displacement-time history of each point on the fabric in three-dimensional space was characterized through 3-D DIC technology, and the process of transverse wave transmission on the fabric after fragment impact was obtained. The calculated results of the finite element model established by truss element agrees reasonably well with the experimental results. The experimental and numerical results indicate that the impact velocity of fragment affects the velocity of transverse wave in the fabric, but does not change its transmission mode. With the increase of pre-tension amount, the propagation mode changes from a cross shape to a rhombic shape and finally to a circular shape, and the wave velocity increases greatly. The wave transmission process in yarns at a mesoscopic level was analyzed through finite element simulation, and the transmission path was determined. It was found that pre-tension accelerated the wave velocity on the stepwise path, causing the transverse wave to reach a farther position in the diagonal direction of the fabric, resulting in different modes of wave transmission. The research content may provide more ways for the application of fabrics in protection.

Metamaterial-induced-transparency engineering through quasi-bound states in the continuum by using dielectric cross-shaped trimers

This study presents a novel approach to activate a narrowband transparency line within a reflecting broadband window in all-dielectric metasurfaces, in analogy to the electromagnetically-induced transparency effect, by means of a quasi-bound state in the continuum (qBIC). We demonstrate that the resonance overlapping of a bright mode and a qBIC-based nearly-dark mode with distinct Q-factor can be fully governed by a silicon trimer-based unit cell with broken-inversion-symmetry cross shape, thus providing the required response under normal incidence of a linearly-polarized light. Our analysis that is derived from the far-field multipolar decomposition and near-field electromagnetic distributions uncovers the main contributions of different multipoles on the qBIC resonance, with governing magnetic dipole and electric quadrupole terms supplied by distinct parts of the dielectric “molecule”. The findings extracted from this research open up new avenues for the development of polarization-dependent technologies, with particular interest in its capabilities for sensing and biosensing.

The impact of plan complexity on calculation and measurement-based pre-treatment verifications for sliding-window intensity-modulated radiotherapy

Background and purposeIn sliding-window intensity-modulated radiotherapy, increased plan modulation often leads to increased plan complexities and dose uncertainties. Dose calculation and/or measurement checks are usually adopted for pre-treatment verification. This study aims to evaluate the relationship among plan complexities, calculated doses and measured doses. Materials and methodsA total of 53 plan complexity metrics (PCMs) were selected, emphasizing small field characteristics and leaf speed/acceleration. Doses were retrieved from two beam-matched treatment devices. The intended dose was computed employing the Anisotropic Analytical Algorithm and validated through Monte Carlo (MC) and Collapsed Cone Convolution (CCC) algorithms. To measure the delivered dose, 3D diode arrays of various geometries, encompassing helical, cross, and oblique cross shapes, were utilized. Their interrelation was assessed via Spearman correlation analysis and principal component linear regression (PCR). ResultsThe correlation coefficients between calculation-based (CQA) and measurement-based verification quality assurance (MQA) were below 0.53. Most PCMs showed higher correlation rpcm-QA with CQA (max: 0.84) than MQA (max: 0.65). The proportion of rpcm-QA ≥ 0.5 was the largest in the pelvis compared to head-and-neck and chest-and-abdomen, and the highest rpcm-QA occurred at 1 %/1mm. Some modulation indices for the MLC speed and acceleration were significantly correlated with CQA and MQA. PCR’s determination coefficients (R2) indicated PCMs had higher accuracy in predicting CQA (max: 0.75) than MQA (max: 0.42). ConclusionsCQA and MQA demonstrated a weak correlation. Compared to MQA, CQA exhibited a stronger correlation with PCMs. Certain PCMs related to MLC movement effectively indicated variations in both quality assurances.

Architectural and planning features of wooden orthodox Churches of Bukovyna using the example of the assumption church, 2 Novoushytska street, Chernivtsi

Wooden churches are an important part of Ukraine's cultural heritage. A significant portion of them has been identified, included in the State Register, and thus is under state protection. It should also be noted that the wooden architecture sites of western Ukraine were included in the UNESCO World Heritage List in 2013 (nomination "Wooden Tserkvas of the Carpathian Region in Poland and Ukraine"). A characteristic feature of the Moldavian-Bukovinian type churches is a plan in the shape of an Orthodox cross. They also feature a high and steep wooden tent roof. The plan consists of three parts: the narthex, the nave, and the altar part. Above each part is a spherical vault in the shape of a half-sphere. The walls are made of wooden beams. The length of the wooden beam’s ranges from 3 to 6 meters. The entrance to the church is always located on the south facade. The prototype of all wooden churches of this type is considered to be the wooden church of the Putna Skete from the 14th century. The architectural monument of national significance, the Assumption Wooden Church, is an outstanding example of folk architecture. The church has retained its authenticity and has been located at its historic site since 1876. Its architectural and planning features lie in the preservation of the traditions of medieval folk architecture of wooden Orthodox churches in Bukovina, serving as a unique authentic example for researchers and restoration scientists The article provides an analysis of the architectural and planning features of the wooden Assumption of the Virgin Mary Church, one of the four wooden churches of national architectural significance located in the city of Chernivtsi. The impact of historical, cultural, and social factors on its architecture is analyzed. Methods and approaches to the preservation and restoration of wooden churches are considered, particularly the use of modern 3D scanning technologies for recording the state of the object and creating its phantom model. The article is illustrated with architectural drawings: site plan, floor plan, and elevations, and provides photographic documentation of facade and interior fragments.

Sharp-rejection dual ultra-wideband bandpass filter using sextuple mode resonator

ABSTRACT In this paper, a novel sextuple mode resonator (SMR) is proposed to design a compact ultra-wide dual-band bandpass filter (BPF) with high selectivity. An even- and odd-mode analysis method is employed to analyze the proposed SMR, and the SMR can excite six resonant modes simultaneously. In addition, a cross shape and several open-circuit stubs are used in the proposed SMR for generating multiple transmission zeros (TZs). The TZs can divide the transmission poles into two groups to form the two passbands. With properly tuned the TZs and the transmission poles, the proposed dual-band ultra-wideband BPF is of high selectivity. The center frequencies (CFs) of the BPF are centered at 1.6 GHz and 5.2 GHz, respectively. The 3-dB fractional bandwidths (FBW) of the two passbands are larger than 145% and 25%, respectively. To demonstrate the performance of the proposed method, an ultra-wide dual-band BPF is fabricated. Measurement results show that the proposed BPF has high band-to-band isolation, wide stopband, low insertion losses (ILs), controllable bandwidth, and compact size. The stopband is up to 12.5 fc1 (fc1 is the center frequency of passband 1st), and the circuit size is only 0.1λg × 0.12λg.

Fast sampling based image reconstruction algorithm for sheared-beam imaging

Sheared-beam imaging (SBI) is an unconventional ground-based optical imaging technique. It breaks through the traditional optical imaging concept by using three coherent laser beams, which are laterally displaced at the transmit plane, to illuminate the target, reconstructing the target image from echo signals. However, the echo data sampling of the imaging system is still not fast enough to reconstruct the high resolution and clear image of the target when imaging the target that is at rapidly changing position and attitude. In order to solve this problem, in this work an image reconstruction method is proposed based on five-beam fast sampling. An emitted beam array arranged in the cross shape with a central symmetrical structure is proposed, and the encoding and decoding method of the imaging system are changed. With a single exposure, the echo signals carry more spectrum information of the target, and the number of reconstructed images can be increased from 1 to 8, which quickly suppresses the speckle effect of the reconstructed image. Firstly, the principle of the imaging technique based on fast sampling is presented. Then, an image reconstruction algorithm based on fast sampling is studied. Eight groups of phase differences and amplitude information of the target can be extracted from echo signals. The wavefront phases are solved by the least-squares method, and wavefront amplitude can be obtained by the algebraic operation of speckle amplitude. The target image is reconstructed by the inverse Fourier transform. The simulation results show that comparing with the traditional three-beam image reconstruction method, the sampling times of echo data needed to obtain the same quality image are reduced from 20 to 5 , which greatly reduces the sampling times of echo data and improves the sampling rate of echo data.

Modifications of Wind Response of Tall-Building Caused by Interfering Effects: A CFD Approach

The wind is an essential factor to consider in the design and construction of tall buildings. As buildings get taller, the wind's impact becomes more significant, and the building's stability and safety become more critical. The interfering effect is one of the significant consequences of a building that needs to be considered. The "interfering effect" is a phenomenon in wind engineering that occurs when an upstream structure affects the wind load on a downstream building. In the past, most of the studies of interfering effects were done with 2D or 3D simulations, only considering one or two parameters from the shape, height, and angle. Therefore, this research attempts to analyze the interfering effect qualitatively and quantitatively from the upstream building to a selected squareshaped principal building by varying the height of the interfering building with different shapes, namely, circular, cross, and triangular shapes with different orientations based on 3D CFD modeling. The commercial CFD package Midas NFX is used for this numerical analysis. The results from the base moment and base shear suggest that a safety factor for interfering effects should be considered in designing the building structures in the city area to ensure the stability of the building, and it is, for the worst-case scenario, 1.3. The pressure fluctuation results highlighted the importance of designing the connection of the cladding system to both compression and tension forces. The findings of the present paper will be crucial in ensuring the stability and safety of the building structures when those buildings are in a dense building environment.

Design of ring and cross shaped graphene metasurface sensor for efficient detection of malaria and 2 bit encoding applications

This paper focuses on the design of a sensor for early stage malaria detection that is highly sensitive and effective. A potentially fatal illness called malaria is brought on by parasites that are spread by mosquito bites. Early detection is essential for effective therapy, but existing diagnostic techniques are frequently trailed by ubiquitous limitations such as time-consuming, expensive, and limited accuracy. By modifying the interactions between light and matter, metasurfaces—artificially structured surfaces made of subwavelength scatterers can improve the sensitivity of graphene-based sensors. In this paper, a graphene metasurface sensor with circular and cross shapes is developed and optimized to attain the highest levels of sensitivity for the detection of malaria. The ultimate objective of this project is to create an inexpensive, and highly effective sensor that can be used for malaria early detection in resource-constrained environments. With a maximum relative sensitivity of 300 GHz/RIU, the sensor exhibits remarkable precision in detecting even minor variations. The FOM values between 0.887 RIU−1 to 1.587 RIU−1 further highlight its exceptional ability to differentiate between various transmittance dips.

Microstructure, mechanical property and cutting performance of (Ti,W)C/Mo/Co/Ni cermet tool material prepared by spark plasma sintering and high frequency induction heating

The (Ti,W)C/Mo/Co/Ni cermet tool material is produced using a combination of spark plasma sintering and high frequency induction heating (HFIH-SPS) mixed sintering technology. This study investigates the influence of various sintering parameters on the microstructure and mechanical properties of (Ti,W)C/Mo/Co/Ni cermet tool material. The findings indicate that the rapid sintering densification of (Ti,W)C/Mo/Co/Ni cermet tool material can be achieved by the mixed sintering technology at a lower sintering temperature. The rapid sintering process observed in this study can be mainly attributed to the plasma activation effect generated by pulse current and the Joule heat effect produced by the metal particles under high frequency induction. The optimized relative density of the (Ti,W)C/Mo/Co/Ni cermet tool material reaches 99.10%, with the hardness of 20.28 ± 0.58 GPa, the fracture toughness of 7.74 ± 0.14 MPa·m1/2 and the flexural strength of 796.12 ± 36.55 MPa. The indentation of (Ti,W)C cermet exhibits a regular cross shape, and the indentation edge is smooth, which indicates a good fracture toughness. The high mechanical properties of (Ti,W)C/Mo/Co/Ni cermet tool material are mainly attributed to the interaction between crystal grain boundary solute strengthening and dislocation movement. The tool has shown good cutting performance during the subsequent dry cutting of 40Cr steel, with the lowest surface roughness Ra value of 1.097 µm.

Modelling of subsurface geological structure related to anomalous magnetotelluric phase data exceeding 90° in Central India

SUMMARY We note anomalous phase (>90°) in magnetotelluric (MT) measurements at several stations along the Narmada river course normal to the Tan Shear Zone (TSZ) in central India. We made efforts to derive a possible cause of the anomalous phase by comparing the results of numerical modelling based on the tectonics of the TSZ with the measured impedance tensor data. A zone of multiple reactivations of the TSZ leads to the formation of a damage zone and conjugate Riedel shear faults parallel and normal to the TSZ, respectively. The conjugate Riedel shear faults act as a pathway for the Narmada River course. The multiple tectonic activities associated with the TSZ induce surficial heterogeneity that results in distortion in the MT data. The Mohr circle and phase tensor analysis establish the effect of distortion in the data. To understand the cause of distortion as well as anomalous phase in the present data, we carried out synthetic 3-D modelling. We modelled the damage zone and conjugate Riedel shear faults by a cross shape. From the results, we noted that the near-surface 3-D heterogeneity across the TSZ critically distorted the YX component of the MT impedance tensor due to the strong current channelling. When the current flows across the conjugate Riedel shear zone (Narmada river course) charges are accumulated along the boundaries of near-surface heterogeneity. The charges associated with the current channelling brought out the reversion of the electric field direction that is reflected in the form of an anomalous phase in the YX component of the impedance tensor in measured data.

On the Torsional Rigidity of Orthotropic Beams with Rectangular Cross Section

The paper deals with the torsional rigidity of homogenous and orthotropic beam with rectangular crosssection. The torsional rigidity of the considered beam is defined in the framework of the Saint-Venant theory ofuniform torsion. Exact and approximate solutions are given to the determination of the torsional rigidity. The shapeof cross section is determined which gives maximum value of the torsional rigidity for a given cross-sectional area.The dependence of torsional rigidity as a function of the ratio shear moduli of beam is also studied.

Long-Term Urban Epidemic and Disaster Resilience: The Planning and Assessment of a Comprehensive Underground Resilience Core

This study utilizes the enclosed and stable environment of underground space for long-term sustainable planning for urban epidemics and disasters. Owing to the COVID-19 epidemic, cities require long-term epidemic–disaster management. Therefore, this study proposed a strategy for integrating multiple functions to plan a comprehensive Underground Resilience Core (URC). A planning and assessment methods of URC were proposed. With this methodology, epidemic- and disaster- URCs were integrated to construct a comprehensive-URC in underground spaces. The results show: (1) Epidemic-resilient URCs adopting a joint progressive approach with designated hospitals can rapidly suppress an epidemic outbreak. (2) The regularity of the morphology of underground spaces determines the area of the URC. Bar-shaped underground spaces have the potential for planning disaster-URCs. (3) The URC planning efficiency ranking is as follows: Bar shapes lead overall, T shapes are second under seismic resilience, and Cross shapes are second under epidemic resilience. (4) The potential analysis of planning a comprehensive-URC in the underground parking in Chinese cities showed that the recovery time can be advanced from 29% to 39% and the comprehensive resilience can be improved by 37.63%. The results of this study can serve as sustainable urban planning strategies and assessment tools for long-term epidemic–disaster management.

A Pixel-Scale Measurement Method of Soil Moisture Using Ground-Penetrating Radar

Ground validation of remote sensing soil moisture requires ground measurements corresponding to the pixel scale. To date, there is still a lack of simple, fast and reasonable methods for soil moisture measurement at pixel scale between point measurements and remote sensing observations. In this study, a measurement method of soil moisture using ground-penetrating radar (GPR) was proposed for pixel scale. We used a PulseEKKOTM PRO GPR system with 250 MHz antennas to measure soil moisture by Fixed Offset (FO) method in four 30 × 30 m2 plots chosen from the desert steppe. This study used a random combination method to analyze soil moisture measurements acquired by different numbers of GPR survey lines. The results showed that two survey lines of GPR would be sufficient under confidence level of 90% with the relative error of 7%, and four survey lines of GPR would be eligible under confidence level of 95% with the relative error of 5% for each plot. GPR measurement can reproduce the spatial distribution of soil moisture with higher resolution and smaller error, especially when two and four survey lines are designed in cross shape and grid shape, respectively. The method was applied to ground validation for the soil moisture from Landsat 8, showing the advantages of stable relative errors, less contingency and reliable evaluation when compared to point measurements. This method is fast and convenient and not limited to a certain pixel, and thus largely benefits the scale matching of remote sensing results and field measurements in ground validation.

Design of double-cross-based smartphone unlock mechanism

Due to the advanced features, smartphones have become an essential and widely adopted electronic device around the world, which can provide various benefits, such as online shopping, e-commerce payment, making friends via social media, email checking and more. Such devices make people’s work and life more convenient and flexible, but how to secure the locally stored phone data is a big problem. With more sensitive or private data stored on these portable devices, there is a significant demand to safeguard smartphones from unauthorized access. Currently, one of the most straightforward and intuitive approaches is to implement an unlock mechanism that asks users to input a correct unlock pattern for authentication, e.g., Android unlock patterns. However, such unlock mechanism can be easily compromised when the unlock pattern is leaked. In this work, we advocate that combining behavioral features with unlock mechanisms is a promising solution, and propose a double-cross-based unlock scheme, called Double-X, which requires users to unlock the device by inputting two cross shapes on the selected dots. For authentication, users have to re-input the selected dots and draw the cross shapes. In the evaluation, we conduct two user studies with 100 participants in total to explore and validate the scheme performance, as compared with two similar unlock schemes. The experimental results indicate that under our scheme, users can reach good success rates with better feedback.

Gain stability improvement of a wideband antenna using an artificial magnetic conductor

AbstractIn this paper, a novel artificial magnetic conductor (AMC) reflector is proposed for gain stability enhancement of a low‐profile wideband bowtie antenna (operates at C‐band). Two AMC reflectors are investigated: the first one is based on a standard square patch cell while the second one is based on a novel cell geometry called modified cross shape (MCS). The two units' cell geometries are studied and optimized to achieve the desirable performances, namely; low‐profile, wide impedance bandwidth, and gain stability. The proposed antenna structure with 5 × 8 MCS unit cells is fabricated and measured. The results show a significant steady gain compared to similar work in the literature. The fabricated structure presents a low thickness of 0.084 λL (λL is the guided wavelength at the lowest frequency, i.e., 3.94 GHz) with 0.85 dB of gain variation over a wide impedance bandwidth of about 50% (3.94–6.61 GHz).

Dual polarization and mutual coupling improvement of UWB MIMO antenna with cross shape decoupling structure

A simple, compact MIMO antenna that operates in the UWB frequency band is presented in this paper. The proposed antenna consists of four elements where the shape of the radiators derived from series modifications of a conventional rectangular patch antenna. Radiators are placed orthogonally to each other to achieve the dual polarization operation and cross shape Defected Ground Structure (DGS) is inserted in the ground plane to improve decoupling between the antenna elements. The designed model was fabricated on FR-4 substrate with dimensions of 48 × 44 × 1.6 mm3 and measurements were performed to validate the simulated results. The fractional bandwidth reaches 112% from 3.1 GHz to 11 GHz with reflection coefficient less than -10 dB and mutual coupling between antenna elements is less than -20 dB. The antenna has a stable radiation pattern, and low gain variation. In addition, the time domain characteristics and diversity performance indicators were evaluated and compared with the standard values. The miniaturized dimensioning of the antenna along with the good performance metrics indicates that the proposed antenna can be used in various UWB applications such as portable handheld devices.

Unequal sized cells based on cross shapes for data collection in green Internet of Things (IoT) networks

Unequal sized cells based on cross shapes for data collection in green Internet of Things (IoT) networks

A Compact High-Isolation Four-Element MIMO Antenna with Asymptote-Shaped Structure

The demand for high-speed wireless communication systems has led to the development of ultrawide-band (UWB) antennas with a compact size and high performance. In this paper, we propose a novel four-port multiple-input multiple-output (MIMO) antenna with an asymptote-shaped structure that overcomes the limitations of existing designs for UWB applications. The antenna elements are placed orthogonally to each other for polarization diversity, and each element features a stepped rectangular patch with a tapered microstrip feedline. The unique structure of the antenna significantly reduces its dimensions to 42 × 42 mm2 (0.43λ×0.43λ@ 3.09GHz), making it highly desirable for use in small wireless devices. To further enhance the antenna's performance, we use two parasitic tapes on the ground plane at the back as decoupling structures between adjacent elements. The tapes are designed in a windmill shape and a rotating extended cross shape, respectively, to further improve the isolation. We fabricated and measured the proposed antenna design on a single-layer substrate (FR4) with a dielectric constant of 4.4 and a thickness of 1 mm. The measured results show that the impedance bandwidth of the antenna is 3.09-12 GHz, with an isolation of -16.4 dB, an envelope correlation coefficient (ECC) of 0.02, a diversity gain (DG) of 9.991 dB, an average total effective reflection coefficient (TARC) of -20 dB, an overall group delay value less than 1.4 ns, and a peak gain of 5.1 dBi. Although there may be some antennas that have better performance in one or two specific aspects, our proposed antenna has an excellent trade-off among all the antenna characteristics including bandwidth, size, and isolation. The proposed antenna also exhibits good quasi-omnidirectional radiation properties, making it well-suited for a range of emerging UWB-MIMO communication systems, particularly in small wireless devices. In summary, the compact size and ultrawide-band capabilities of the proposed MIMO antenna design, coupled with its improved performance compared to other recent UWB-MIMO designs, make it a promising candidate for 5G and next-generation wireless communication systems.

A two-DOF linear ultrasonic motor utilizing the actuating approach of longitudinal-traveling-wave/bending-standing-wave hybrid excitation

Ultrasonic motors (USMs) have been extensively investigated for a few decades, but it is still required to improve their thrust force (or torque) density and/or power density for practical usage. According to conventional actuating methods, the dimensions of the transducers are difficult to greatly change after modal degeneration; this restricts the possibility of weight reduction. To tackle this problem, an actuating approach via longitudinal-traveling-wave (LTW) and bending-standing-wave (BSW) hybrid excitation is proposed and applied to a two-DOF linear ultrasonic motor in cross shape. Here, the driving force is generated with the LTW excited by modulating the phases according to the lengths of the transducers, while the elliptical motion shape is adjusted by tuning the BSW for optimal actuation. To assess the validity, a pair of Mason-circuit-based dynamic models were initially constructed to discuss three-dimensional vibration properties of the LTW and BSW on the cross-shaped transducer. Subsequently, a prototype with the size of 68 × 68 × 28 mm3 was designed and fabricated to form a motor capable of horizontally moving in the x and y axes. Finally, the movement and load characteristics were evaluated experimentally. At 250 V voltage and 27.4 kHz frequency, the motor yielded the maximal thrust force, no-load sliding speed, and maximal output power of 42.1 N, 833 mm/s, and 7.7 W, respectively, along the x axis; and 40.2 N, 877 mm/s, 8.1 W, respectively, along the y axis. Moreover, the thrust force density and power density reach respectively 188.3 N/kg and 36 W/kg, exceeding the values of most conventional two-DOF linear USMs. These results demonstrate high actuating capability induced by the LTW/BSW hybrid excitation and provide a new method to design powerful two-DOF linear motors.