Identical Pieces Research Articles

The stochastic response of fatigue crack growth in scaled components

In fatigue testing the number of cycles and crack length to failure are recognised to be stochastic quantities necessitating repetitive testing to draw out statistically meaningful measures. The origin of this phenomena is uncertainty in the detailed microstructure, where (from a microstructural perspective) there exists no two identical test pieces. The situation is further compounded under scaled testing of polycrystalline specimens due to a form of coarsening with scaled samples containing less grains than the full-size test piece with samples drawn from the same material stock. Although microstructural uncertainly impedes predictability, implying the need for a probabilistic framework, it is nonetheless important to capture deterministic aspects that feature in any stochastic model. The theory advanced in this paper builds on the finite similitude scaling theory and the two-experiment first-order rule that features length as an invariant. Length invariance is shown to be critically important for fatigue as it caters for the many aspects of the microstructure that are not scaled under scaled testing. A diffusional stochastic model is introduced in the paper that is constrained by the first-order finite similitude rule. The approach is shown to enforce necessary determinism despite the uncertainties present and unlike many of the rules that are currently applied in fatigue analysis, it is applicable over a large range of length scales. Popular growth laws for long cracks are examined under the new framework, which transpires to be remarkably straightforward to apply.

Iron Sulfide Microspheres Supported on Cellulose-Carbon Nanotube Conductive Flexible Film as an Electrode Material for Aqueous-Based Symmetric Supercapacitors with High Voltage.

Nanostructured iron disulfide (FeS2) was uniformly deposited on regenerated cellulose (RC) and oxidized carbon nanotube (CNT)-based composite films using a simple chemical bath deposition method to form RC/CNT/FeS2 composite films. The RC/CNT composite film served as an ideal substrate for the homogeneous deposition of FeS2 microspheres due to its unique porous architecture, large specific surface area, and high conductivity. Polypyrrole (PPy), a conductive polymer, was coated on the RC/CNT/FeS2 composite to improve its conductivity and cycling stability. Due to the synergistic effect of FeS2 with high redox activity and PPy with high stability and conductivity, the RC/CNT/FeS2/PPy composite electrode exhibited excellent electrochemical performance. The RC/CNT/0.3FeS2/PPy-60 composite electrode tested with Na2SO4 aqueous electrolyte could achieve an excellent areal capacitance of 6543.8 mF cm-2 at a current density of 1 mA cm-2. The electrode retained 91.1% of its original capacitance after 10,000 charge/discharge cycles. Scanning electron microscopy (SEM) images showed that the ion transfer channels with a pore diameter of 5-30 μm were formed in the RC/CNT/0.3FeS2/PPy-60 film after a 10,000 cycle test. A symmetrical supercapacitor device composed of two identical pieces of RC/CNT/0.3FeS2/PPy-60 composite electrodes provided a high areal capacitance of 1280 mF cm-2, a maximum energy density of 329 μWh cm-2, a maximum power density of 24.9 mW cm-2, and 86.2% of capacitance retention after 10,000 cycles at 40 mA cm-2 when tested at a wide voltage window of 1.4 V. These results demonstrate the greatest potential of RC/CNT/FeS2/PPy composite electrodes for the fabrication of high-performance symmetric supercapacitors with high operating voltages.

Integrating Parabolic Trough Solar Fields Into Computerized Maintenance Management Systems

Computerized maintenance management systems for power plants are not well suited for application in solar fields. They work well for tracking maintenance requirements on the hundreds or even thousands of pieces of equipment in conventional power plants, but they do not work as well tracking the maintenance requirements on hundreds of thousands of identical pieces of equipment found in a solar field. A database application, known as a field status program, is being developed for tracking the maintenance and status of collectors and components in parabolic trough solar fields as a complement to the computerized maintenance management system. This system, patterned after a similar system developed by the KJC Operating Company in the 1990s, provides a valuable tool for the O&M of parabolic trough solar fields. This paper describes the development and application of the tool and the new expanded capabilities that are being added to further enhance the O&M of solar fields.

Quality and quantity: How contexts influence the emergence of teacher bias

A growing body of research has demonstrated that teachers’ judgements may be biased by the demographics and characteristics of the students they teach. However, less work has investigated the contexts in which teachers may be most vulnerable to bias. In two pre-registered experimental studies we explored whether the quality of students’ work, and the cognitive load placed on the grader, would influence the emergence of biases relating to socioeconomic status (SES) and ethnicity. In Study 1, teachers (N = 397) graded work of either high or low quality that had ostensibly been written by a student who varied in terms of SES and ethnicity. We found that SES and—to a lesser extent—ethnicity biases were more likely to manifest when the standard of work was below average, largely favouring a student from an affluent White background. In Study 2, an undergraduate sample (N = 334) provided judgements based on an identical piece of work written by a student who varied by SES and ethnicity. Importantly, they formulated these judgements whilst working under high or low cognitive load, which was manipulated via a simultaneous listening task. Results showed that under high cognitive load, a student from an affluent White British background was afforded a boost in grading that was not afforded to Black Caribbean and/or lower SES students. These findings highlight contexts in which teachers may be most prone to biased judgements and should be used by educational institutions to de-bias their workflows, workloads and workforces.

Exploring the Line between Creation and Creator in Mabou Mines’s Glass Guignol: The Brother and Sister Play

Abstract During the last ten years of his life, Lee Breuer, who passed away in 2021, had been interested in framing Tennessee Williams’s canon, particularly the late plays, through the perspective of the grotesque and the Grand Guignol. Mabou Mines’s Glass Guignol: The Brother and Sister Play (2017), directed by Breuer and conceived by Breuer and Maude Mitchell, views Williams’s work alongside Mary Shelley’s Frankenstein (1818) in order to expose the grotesque truth of the messy and complex creative process. On one level, Glass Guignol is a multilayered exploration of the relationship between Williams and his sister Rose, whose story of courage in facing the mental and emotional challenges that culminated in an eventual lobotomy in 1943 was the inspiration for several of the female characters in both his canonical early plays and his less familiar later works. Developed through various workshops and staged scenes since 2011, the finalized version of Glass Guignol interweaves the story of Rose herself with Williams’s various fictional creations of women who reflect her spirit, if not necessarily her actual experiences: Laura in The Glass Menagerie (1945), Catherine in Suddenly Last Summer (1958), Clare in The Two-Character Play (revised between 1967 and 1976), and Nance in A Cavalier for Milady (c. 1976). While a symbiotic brother-sister love is at the center of The Two-Character Play, which serves as the primary framework of Breuer’s piece, it was also a common preoccupation for Romantic poets. Glass Guignol uses this relationship to delve into broader territory, asking questions about the relationship between creator and creation, and taking Frankenstein as yet another framework for the complexities and contradictions of this partnership. With its nineteenth-century asylum staging, the play foregrounds the grotesque and the Grand Guignol, both sensibilities that embrace contradiction, instability, and a lack of boundaries. Ultimately, Breuer explores how the artist sews together bits and pieces of identity, emotion, and experience in the pursuit of that seamless and perfect illusion of reality.

Heat behavior and axial temperature distribution of a Ti-6Al-4V alloy in a superconducting induction heater with a controllable magnet structure

Ti-6Al-4V (TC4) metal billets can usually be preheated by gases, resistance furnaces, and conventional induction heater powered by alternating current. However, the disadvantages of these heating methods are long heating time and small skin depths. The novel superconducting induction heater has several advantages in terms of heating quality, heating efficiency, heating time and axial temperature control. It has gained successful commercial application in the large aluminum extrusion industry in 2021. However, no studies on TC4 heating behavior using a superconducting induction heater have been reported, and no studies on uniform and gradient temperature characteristics of TC4 in superconducting induction heater. The uniform temperature distribution of TC4 is helpful to reduce the heating residual stress of forgings. The gradient temperature distribution of TC4 billet can obtain different properties in different parts of the same TC4 billet, which is suitable for manufacturing functionally graded materials. In this study, a high-temperature superconducting (HTS) direct-current (DC) induction furnace was firstly used to perform heating experiments for TC4 metal billets of 1250 mm length and 220 mm diameter. The application of the superconducting magnet for induction heating allows for high-power and fast heating of the TC4 billet at an extremely low frequency (4 Hz). The HTS induction heater technology has the advantages of high penetration depth, high energy efficiency (>82%), high heating uniformity, and controllable temperature distribution. Additionally, it improves the metal heating quality and reduces the heating cost. The 10 identical iron pieces of superconducting magnet on both sides of the iron core can be adjusted independently. The gradient and uniform temperature distributions of the thermally optimized TC4 billets were experimentally determined using adjustable electromagnetic heating power. Subsequently, the heating behavior of TC4 billets was modeled and compared using the numerical multiphysical finite element method; the results obtained using this method are in agreement with the experimental results. An expert database has been established for the heating strategy of TC4 billets. The optimized axial temperature distribution was analyzed for three different TC4 billet diameters (Φ220, Φ300, and Φ446 mm). The obtained gradient and uniform axial temperature distributions had an error of less than ±3 °C, and the adjustable difference at two-ends temperature of TC4 billets was in the range 10–100 °C/m. Finally, the maximum thermal stress on the TC4 billet during heating also was analyzed. The results of this study will be useful of the novel HTS induction heater application for TC4 billet heating, and axial temperature control. The uniform temperature distribution control will reduce the heating residual stress of forgings. The gradient temperature distribution of TC4 billet is suitable for manufacturing functionally graded materials.

Turnover polypyrrole decorated cotton fabric based solar evaporator for cost-effective and steady desalination

Interfacial solar steam production (ISSP) is an attractive technique for extracting freshwater from seawater. However, significant efforts have been focused on designing solar evaporators with delicate structures to achieve excellent evaporation rates and steady desalination performance, which result in sophisticated processes and high costs that inhibit their practical application. Here, a cost-effective turnover polypyrrole decorated cotton fabric (PPy-CF) based solar evaporator was designed by sewing two identical pieces of PPy-CF photothermal material to the top and bottom of polyethylene foam (PF). The polyester fiber pillar (PFP) inserted into the PF incorporates vertical water-transporting channels to pump water into the PPy-CF efficiently. The heat dissipation of the PPy-CF was minimized by adjusting the number of PFP. The appropriate water supplied by the PFP water transporter enables the PPy-CF-based solar evaporator to attain an excellent evaporation rate of 1.56 kg m−2 h−1 and a remarkable photothermal efficiency of 90.45% under 1-solar intensity. Notably, the sufficient water provided by the PFP water transporter allows the PPy-CF-based solar evaporator to achieve a steady desalination performance of 8 h, and the evaporation rate maintains around 1.31 kg m−2 h−1. Moreover, this solar evaporator can be self-cleaning by turning it over. Outdoor cycle experiments demonstrated that a 1 m2 PPy-CF-based solar evaporator could produce approximately 6 kg of freshwater within 10 h. Designing a 1 m2 this turnover solar evaporator costs about 1 dollar. The cost-effectiveness, simplicity in design, self-cleaning ability, and steady desalination performance make the turnover PPy-CF-based solar evaporator a promising solution to alleviate freshwater shortages.

A modular approach for creation of any bi-axial woven structure with congruent tiles

Modularity is a fundamental and intriguing property of fabrics. Given the same set of threads, one can construct different geometries and therefore physical behavior simply by changing how those threads are linked to each other. As a result, fabrics have been studied with great interest in engineering applications. However, most engineering applications model fabrics as composite structures reinforced with a secondary material that fills the gaps between thread elements.In this work, we first show the existence of threads that are space-filling without the need for other materials. We then introduce a simple approach to construct such space-filling threads by using a single modular element that can be obtained by partitioning a cube into two yin-yang type identical pieces. These yin-yang type congruent tiles can directly be constructed by using a parametric approach. Another property of these tiles is that they are foldable, i.e., they can be constructed by folding planar materials. We show that there exist infinitely many such congruent tiles. We further demonstrate that any 2-way 2-fold woven structure can be constructed by translated and rotated versions of such congruent tiles.

Depth profiling and standardization from the back side of a sample for accurate analyses: Emphasis on quantifying low-fluence, shallow implants in diamond-like carbon.

Back-side thinning of wafers is used to eliminate issues with transient sputtering when analyzing near-surface element distributions. Precise and accurate calibrated implants are created by including a standard reference material during the implantation. Combining these methods allows accurate analysis of low-fluence, shallow features even if matrix effects are a concern. Implanted Na (<2.0 × 1011 ions/cm2 , peaking <50 nm) in diamond-like carbon (DLC) film on silicon (solar wind returned by NASA's Genesis mission) was prepared for measurement as follows. Implanted surfaces of samples were epoxied to wafers and back-side-thinned using physical or chemical methods. Thinned samples were then implanted with reference ions for accurate quantification of the solar wind implant. Analyses used a CAMECA IMS 7f-GEO SIMS in depth-profiling mode. Back-side-implanted reference ions reduced the need to change sample mounts or stage position and could be spatially separated from the solar wind implant even when measuring monoisotopic ions. Matrix effects in DLC were mitigated and the need to find an identical piece of DLC for a reference implant was eliminated. Accuracy was only limited by the back-side technique itself. Combining back-side depth profiling with back-side-implanted internal standards aides quantification of shallow mono- and polyisotopic implants. This technique helps mitigate matrix effects and keeps measurement conditions consistent. Depth profile acquisition times are longer, but if sample matrices are homogeneous, procedural changes can decrease measurement times.

Heuristic algorithms for the special knapsack packing problem with defects arising in aircraft arrangement

This paper addresses a special knapsack packing problem in which identical pieces are packed into an irregular board with unusable regions to maximize the number of pieces. This problem arises from a real-world application in which the aircraft is placed on the carrier’s deck to maximize the number of aircraft. We propose the support polygon concept to solve one of the challenges of the problem, i.e., ensure that the support points inside the piece’s interior are located within the board when the piece protrudes from the board. Many strategies for determining the piece’s location and selecting the rotation angle of the piece are proposed and compared. Based on these techniques, we propose a deterministic heuristic algorithm to solve the problem. In addition, we develop an improved version of the algorithm, called the recursive search heuristic algorithm, to get higher-quality solutions. Many experiments were conducted to test the performance of different combinations of strategies and the proposed algorithms. The computational results show that the proposed algorithms have a strong capacity for obtaining good solutions, and updating many of the best results in the benchmark instances provided by the literature.

Roles of socioeconomic status, ethnicity and teacher beliefs in academic grading.

Educational outcomes in the United Kingdom vary as a function of students' family background, with those of lower socioeconomic status (SES) and certain ethnic minority groups among the worst affected. This pre-registered study investigates: (i) whether knowledge about students' socioeconomic and ethnic background influences teachers' judgements about the quality of their work and potential for the future, and (ii) the role of teachers' beliefs-most notably about meritocracy-in their practices. Our findings are based on the responses of 416 in-service (88%) and trainee (12%) teachers who successfully passed several stringent exclusion criteria. As part of a 2 × 2 independent measures design, teachers were randomly assigned to assess an identical piece of work ostensibly written by a student who varied by SES (higher vs. lower) and ethnicity (White British vs. Black Caribbean). Following this, they responded to several measures assessing their beliefs about education. Teachers judged students of lower SES to be inferior to students of higher SES across a range of indicators. By contrast, we found no evidence of racial bias in teachers' judgements, though potential reasons for this are discussed. Teachers who believed that schooling is meritocratic were significantly less likely to support equity-enhancing teaching practices and initiatives. Unconscious teacher biases and beliefs may be contributing to the relative underperformance of students from poorer backgrounds. These findings provide a mandate for educational institutions to help teachers reflect upon, and develop the skills required to mitigate potentially harmful biases.

Design and characteristic analysis of multi-degree-of-freedom ultrasonic motor based on spherical stator.

The multidimensional motion ultrasonic motor with a single spherical stator is studied in this paper. It has the characteristics of miniaturization and can be used in precision motion applications. By bonding six identical pieces of piezoelectric ceramic onto the stator and applying the voltage signal of high frequency, the deformation of the inverse piezoelectric effect is used to excite the stator yaw vibration mode. The orthogonal superposition of the modes of the spherical stator on the driving foot produces elliptical trajectory around X, Y, and Z directions by different excitation methods. According to the yaw vibration mode of the spherical stator, 12 driving feet are designed to drive the rotation of the spherical rotor. The structure and mechanical characteristics of the motor are simulated by using simulation software, and the transient response of the stator driving foot was obtained, which proved its feasibility. Finally, the output performance of the motor in actual operation is given through experiments, which provides a new reference scheme in the field of precise multi-degree-of-freedom motion. At a voltage of 100V and a frequency of 26.7kHz, the prototype has a no-load speed of 73, 70, and 114 rpm around X, Y, and Z axes, respectively.

The experimental study on damaged square columns strengthened by reinforcement mesh steel fiber

Eight common reinforced concrete columns were damaged by different sizes loads. The damaged reinforced concrete columns were strengthened by reinforcement mesh steel fiber. Three identical test pieces were made to explore the dispersion of the reinforcement method. The axial compression experiment was researched by factor of mortar types, damage degree, the lateral and longitudinal spacing. The formula of the axial bearing capacity of damaged square columns were strengthened by reinforcement mesh steel fiber was proposed. The calculated values agreed well with the experimental results. The test results showed that the damaged square columns were strengthened by reinforcement mesh steel fiber was an effective reinforcement method. This method was less discrete and can not only improve the ultimate bearing capacity, cracking load ductility and anti-cracking ability, but also the mechanical properties and failure mode can be effectively improved.

A preliminary investigation of the response ofOctopus vulgaristo experimental stimuli in the wild

ABSTRACTWe tested the feasibility of conducting three standard behavioural tests modified from laboratory experiments with Octopus vulgaris in its natural habitat. Twenty wild octopuses from around the island of Capri (Mediterranean Sea) were filmed as two novel objects (a piece of white plastic and an identical piece of black plastic), an artificial prey item (a realistic rubber crab lure) and a conspecific (simulated by reflection in a mirror) were presented by experimenters on SCUBA. All of the objects elicited responses from at least 20% of the octopuses, particularly the artificial crab (50% made contact). This rate of engagement with objects (≤50%) is much lower than seen in analogous laboratory experiments (&amp;gt;78%). However, among those that did respond to an object, latencies to touch were in the same range as those observed in the laboratory. This demonstrates the feasibility of conducting simple behavioural assays with O. vulgaris in the field, opening the door to a more systematic approach to behavioural study of octopuses in the wild. Such studies will, however, require larger sample sizes than laboratory experiments in order to compensate for lower engagement rates.

Binary-Like Topology Optimization of Piezoelectric Metamaterial Plate with Interface Circuits Using Extended Plane Wave Expansion Method

Piezoelectric metamaterial plate (PMP) is being investigated for structural vibration energy harvesting (SVEH), in which an interface circuit is often used. Thus, it is a challenge to perform bandgap optimization of such an elastic–electro–mechanical coupling system. This paper presents a binary-like topology optimization scheme by dividing the unit cell into identical pieces, where a {0, 1} matrix is optimized to indicate material distribution. Firstly, a unified motion equation is derived for the elastic plate and the piezoelectric patch, and an electromechanical coupling model is built for a self-powered synchronized charge extraction circuit. Then, an extended plane wave expansion method is presented to model the bandgap character of the PMP with interface circuits (PMPICs), and the numerical solution of the dispersion curves is derived based on the Bloch theorem. Next, an extended genetic algorithm is applied for the topology optimization of the PMPIC. In the end, numerical and finite element simulations are performed to validate the proposed method. The results demonstrate that both the structure and the circuit can be optimized simultaneously to obtain the maximum first-order bandgap at a given central frequency. Therefore, the proposed method should provide an effective solution for the topology optimization of a PMPIC for broadband SVEH.

Monolithic Co-N-C membrane integrating Co atoms and clusters as a self-supporting multi-functional electrode for solid-state zinc–air batteries and self-powered water splitting

For practical applications in electrochemical devices such as zinc air batteries and alkaline water electrolyzers, an efficient electrode design with satisfactory multifunctional catalytic activity is a pivotal prerequisite. Herein, a self-supporting monolithic electrode for electrocatalyst-based devices with exceptionally high multi-functional catalytic activity is presented. The optimized tri-functional activity is recorded at a current density of 10 mA cm−2 with an overpotential at 36 mV for HER, and 229 mV for OER, indicating 1.51 V in an alkaline water electrolyzer, as well as a half-wave potential of 0.858 V for ORR. More importantly, the catalyst electrode exhibits an extremely low charge–discharge potential gap (ΔE less than 0.5 V) in solid-state rechargeable zinc-air batteries, attributed to its monolithic characteristics. Consequently, a self-powered hydrogen production system is driven by the identical pieces of the CoNC monoliths and zinc foil as a power source.

Book Embedding of Infinite Family ((2h+3 2))-Crossing-Critical Graphs for h=1 with Rational Average Degree r∈(3.5,4)

A principal tool used in construction of crossing-critical graphs are tiles. In the tile concept, tiles can be arranged by gluing one tile to another in a linear or circular fashion. The series of tiles with circular fashion form an infinite graph family. In this way, the intersection number of this family of graphs can be determined. In this research, has been formed an infinite family graphs Q_((1,s,b) ) (n) with average degree r between 3.5 and 4. The graph formed by gluing together many copies of the tile P_((1,s,b) ) in circular fashion, where the tile P_((1,s,b) ) consist of two identical pieces of tile. And then, the graph embedded into the book to determine the pagenumber that can be formed. When embed graph into book, the vertices are put on a line called the spine and the edges are put on half-planes called the pages. The results obtained show that the graph Q_((1,s,b) ) (n) has 10-crossing-critical and book embedding of graph has 4-page book.

Effect of Tillage Depth and Tractor Forward Speed on Some Technical Indicators of the Moldboard Plow

Due to the lack of many in-depth studies on the moldboard plow in the conditions of the Republic of Yemen before, this research was conducted with the aim of finding the effect of forward tractor speed and depth of tillage on the slippage percentage, field capacity, field efficiency and fuel consumption. The experiment was carried out in the farm of the Agriculture and Veterinary Medicine, Thamar University in the year 2015. The Massey Ferguson 275 tractor (MF 275) 67.43 hp (50.3 kW) with moldboard plow was used. Three replicates were used for each experiment, the experiment included three depths (10 cm, 20 cm, 30 cm) and three speeds (4.24, 5.54 and 6.75) (km / h) for each repeat, and the experiment included 27 identical experimental pieces. The results showed that increasing depth from 10 cm to 20 cm and 30 cm lead to increased slippage percentage (from 11.55 to 19.79 and 25.39 %), and fuel consumption (from 18.97 to 23.00 and 26.27 l/ha), but decreased field capacity (from 0.324 to 0.294 and 0.272 %) and field efficiency (from 59.39 to 53.80 and 50.04 %). Increasing speed from 4.24 to 5.54 and 6.75 km/h lead to increased slippage percentage (from 13.52 to 20.16 and 23.06 %) and field capacity (from 0.246 to 0.296 and 0.348 %) but decreased field efficiency (from 57.54 to 53.49 and 51.56 %) and fuel consumption (from 26.87 to 22.57 and 18.8 %). The first depth (10 cm) with first speed (4.24 km/h) gave the lowest slippage percentage rate (8.49 %) and the highest rate of field efficiency (61.08 %). The third speed (6.75 km/h) with first depth (10 cm) gave the highest rate of field capacity (0.381 ha/h) and les rate of fuel consumption per unit area (15.5 l/ha). The third depth (30 cm) with third speed (6.75 km/h) gave highest rate of slippage percentage (30.37 %). While the third depth (30 cm) with first speed (4.24 km/h) gave the highest rate of fuel consumption per unit area (30.8 l/h). We recommend the use of third speed (6.75km/h) and first depth (10 cm) because it recorded the highest rate of the field capacity and the lowest rate of fuel consumption per unit area (15.5).

Experimental and numerical investigation of the influence of temperature on the fracture behavior of high impact polystyrene evaluated by the J-integral approach using multiple specimen method

The aim of the present work is to study the mechanical behavior in fracture of high impact polystyrene (HIPS) subjected to tensile tests under the effect of temperature to determine the R-curves. The theory of the J-integral contour has been used for the development of a characterization method of the fracture strength appropriate to the case of this non-linear elastoplastic polymer material. To this end, we used the method of multiple specimens (Single edge notch tension SENT) of thin thickness; we used several identical test pieces containing cracks of the same lengths. The tensile tests were conducted under different temperatures, ranging from 25°C to 100°C. The results suggested a very temperature-dependent behavior due to significant increase in crack resistance as demonstrated by a comparison of JIC values related to initiation of crack propagation. The fracture energy absorbed as a function of the temperature suggested that the increase of the temperature is marked by the brittle-ductile transition in the material, which we confirmed numerically via a CASTEM software simulation.

Wideband circularly polarized aperture coupled DRA array with sequential-phase feed at X-band

A novel 2 × 2 wideband dielectric resonator antenna (DRA) array with circular polarization and fed with a sequential-phase feeding network at the X-band is presented in this paper. The proposed DRA array is fed by an aperture coupled feeding network. Each DRA element is constructed by joining two identical pieces of half-cylindrical shape; those are shifted with respect to each other to produce two orthogonal modes, in order to achieve a broadband circular polarization and wideband impedance matching simultaneously. The rigorous analysis and optimization processes throughout this paper are carried out numerically. The proposed array demonstrates a maximum realized gain of 10.3 dB. The measured matching bandwidth ranges from 8 to 12 GHz (40%), with about 37% 3-dB axial ratio bandwidth within the matching bandwidth. The quadruple DRA elements array is fabricated, and its scattering parameters and far-fields performance are measured to validate the numerical results. Acceptable agreement between the simulated and measured results is accomplished. It is demonstrated that the proposed antenna is a potential candidate for radar and satellite applications at X-band.