Rectangular Plane Research Articles

A Compact Quad-Band Sickle-Shaped Monopole Antenna for燝SM�00/WiMax/WLAN Applications

In this paper a novel, compact, microstrip-fed, quad-band monopole antenna is presented for the application of Global System for Mobile communication (GSM 900), Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN). The proposed antenna comprises of a sickle-shaped structure with four circular arc strips, and a modified rectangular ground plane. The four strips of the antenna are independently responsible for the four different resonant frequencies of the operating bands and can be tuned separately to control the radiation performance. The proposed quad-band antenna is designed to resonate at 940 MHz for GSM 900, 2.5 and 3.5 GHz for WiMAX and 5.85 GHz for WLAN applications. At the four intended operating bands, the antenna exhibits impedance bandwidth of 60 MHz (905–965 MHz), 80 MHz (2.45–2.53 GHz), 110 MHz (3.48–3.59 GHz) and 2.39 GHz (4.82–7.21 GHz), respectively. At the resonance frequency of the four bands, the gain of the proposed antenna is obtained as 4.2, 2.5, 1.7 and 1.9 dBi, respectively. A prototype of the designed antenna is fabricated and a good agreement between simulated and measured results is observed. Furthermore, the proposed antenna shows good radiation characteristics and gains at all the four operating bands.

Low Complexity Linear Detectors for Massive MIMO with Several Antenna Array Configurations: A Comparative Study

In Multiple-Input Multiple-Output (MIMO), there is multi-user interference because of the limited number of antennas at the Base Station (BS). Deploying more antenna elements at the BS to decrease the multi-user interference is a costly solution. Therefore, changing the configuration of antenna arrays at the BS is implemented as an alternative. In this paper, the impact of BS antenna array configurations on the performance of massive MIMO detection techniques is investigated where four different antenna array configurations are implemented at the BS: Uniform Linear Array (ULA), Uniform Rectangular Planar Array (URPA), Uniform Circular Array (UCA) and Uniform Circular Planar Array (UCPA). The performance of the massive MIMO system is based on the millimeter wave (mmWave) channel that depends on the array response vector of the BS antenna array configuration. To the best of our knowledge, this is the first paper to investigate the impact of antenna array configurations at the BS on the performance and the computational complexity of massive MIMO detection techniques. Numerical results show that the implementation of URPA at the BS with MMSE detection algorithm can achieve the best performance of BER=10−4 at SNR = 9dB. The deployment of the UCA at the BS with the successive over-relaxation (SOR), the Gauss-Seidel (GS), and the conjugate-gradient (CG) detection methods provides a performance of BER=10−4 at SNR = 12dB when the number of iterations equals eight. In the case of using the UCA at BS with the Richardson (RI) detection method, the number of iterations is required to be increased to achieve the same performance. To achieve BER=10−4, the detector based on the CG method has the lowest computational complexity while the RI method has the highest complexity.

Wind Excited Action around Tall Building Having Different Corner Configurations

Aeroelastic instabilities are common in square or rectangular plan shape structures due to the development of powerful vortices by the rolling motion of the separated shear layers. Windward corner modifications such as corner cut, recession, rounded, and slotted help to reduce instabilities. Codal recommendations about common shapes like square, rectangle, triangle, and circular shapes are available in different international standards, but they did not provide the detailed analysis results for the different regular shapes with corner configurations. Although analysis was performed on various plan shapes of tall buildings using the computational fluid dynamics technique through k‐ε turbulence model, a very small number of studies were performed on particular shapes with different corners having same plan area and height. The mean pressure coefficients of Model‐A and Model‐B were compared with various international standards and wind tunnel data, respectively, for validation, showing a nearly equivalent consistency; however, international standards consist of coefficients at 0° and 90° wind angles only. Wind effects on building shapes having different corners change the characteristics of the separated shear layer and reduce the downstream wake which helps to reduce drag and lift forces simultaneously. Recent study shows that the windward pressure distribution pattern is almost independent of building size and height. Therefore incorporation of corners in building helps to reduce the forces caused by extreme wind. A very large amount of numerical simulation data about wind pressure is generated, which can be used by the designer while designing such a building for wind load. Comparison have been made between buildings having different corners under same wind speed, and Model‐D (round corner) performed very well against the wind.

Conformal topology optimization of multi-material ferromagnetic soft active structures using an extended level set method

Ferromagnetic soft active structures using embedded ferromagnetic particles in the soft polymer matrix can generate flexible locomotion and change configurations remotely, rapidly, and biologically friendly with an applied magnetic field. To achieve the desired motion, these soft active structures can be designed by tailoring the layouts of the ferromagnetic soft polymer. Although many magnetic soft active structures have been designed and fabricated, they are limited by the developer’s intuition and experience. Structural topology optimization has become a promising method to achieve innovative structures by optimizing the material layout, opening a new path for architecting ferromagnetic-driven active structures. Given the widespread adoption of thin-shell structures for soft robots, the extended level set method (X-LSM) and conformal geometry theory are employed to perform topology optimization of the ferromagnetic soft active structures on manifolds. The boundary evolution on a free-form 3D surface can be transferred into a 2D rectangular plane by solving a modified Hamilton–Jacobi equation weighted by conformal factors. The reconciled level set (RLS) method is firstly implemented within the X-LSM framework in this paper to enable the design of multi-material ferromagnetic soft active structures on free-from surfaces. The design objective consists of a subobjective function for kinematic requirement and a subobjective function for minimum compliance. The shape sensitivity was analyzed using the material time derivative and the adjoint variable approach. The proposed method was applied to design several single and multi-material ferromagnetic soft active structures. Two topologically optimized designs have been printed using functional 3D printing technology, or the so-called 4D printing, to physically realize soft active structures with built-in functionalities. The results of the numerical verification and experimental validation demonstrate the effectiveness of the proposed design and fabrication framework.

Seismic collapse performance of reinforced concrete moment frame structures with plan irregularity

SummaryTo study the effect of plan irregularity on the collapse performance of reinforced concrete (RC) moment frame structures, three groups of seven‐story RC frame structures with different plan layout, one rectangular and two L‐shaped with different dimensions, were designed and numerically studied. The length‐to‐width ratio, protrusion ratio (length of protruding part divided by the total length), and the length‐to‐width ratio of the protruding part were selected as the study parameters. The fragility curves for the collapse limit state of each structure were generated through incremental dynamic analysis, and the collapse margin ratios of the structures were derived. It is found that the seismic collapse performance of the structure with the rectangular plan is significantly affected by the length‐to‐width ratio, and setting a threshold value of 6 is reasonable. For the L‐shaped structure, the influence of the protrusion ratio and the length‐to‐width ratio of the protruding part on the average collapse resistance capacity is not significant. A larger value increases the collapse resistance under rare earthquake. Effect of setting seismic joint in the L‐shaped structure is also studied, and the results indicate that setting the seismic joint or not hardly influences its seismic collapse performance.

The Remaining Buddhist Architecture in Fu’an, the Core Hinterland of the Changxi River Basin

The Changxi River Basin is a small root-like watershed, surrounded by mountains on three sides and facing the sea to the southeast. It is located on the border between Fujian and Zhejiang on the southeast coast of China. The area gave rise to the Changxi Culture that began in the Sui and Tang Dynasties and flourished in the Song Dynasty. Buddhism in the Changxi Basin was introduced no later than the 9th century. As the core hinterland of the Changxi Basin, Fu’an has always been an important center for Buddhism in Eastern Fujian. It reached its peak in the 10th to 13th centuries during the Song Dynasty. This article conducts a comprehensive investigation and study of the existing Buddhist temple sites and relics in Fu’an. It highlights these structures’ single-bay pattern of construction, based on rectangular plans in which the longitudinal axis extends along the plan’s direction of depth. This is a pattern rarely seen in the history of Chinese Buddhist architecture. The paper also summarizes a common element in these temples, their petal-shaped corrugated stone pillars which are divided into eight segments. Lastly, it illustrates the evolution of the temples in the Changxi River Basin from single-bay layouts to those with widths of multiple bays and indicates the unique status and associated values of single-bay Buddhist temples in the history of southern Buddhist architecture. The study examines new local findings and ideas for the study of Chinese Buddhist architectural history, providing academic support for the protection and research of Buddhist architectural heritage in Southeast China.

Solving an EPQ model with doubt fuzzy set: A robust intelligent decision-making approach

This article deals with the novel application of complex neutrosophic set in a production inventory model. First of all, we develop a new set named doubt fuzzy set the real and imaginary parts of which are the membership functions of fuzzy variables. The real part of the set is coined as “true or sure” and that for complex part it is defined as “hesitation or suspect” membership functions or it may be defined as “optimism” and “pessimism” respectively in the psychological view point. Then, we give some definitions of doubt fuzzy set in a rectangular complex plane. Subsequently, we give novel defuzzification method by introducing the concept of power of difficulty/ opportunity power which are complementary to each other. Secondly, we develop a backlogging economic production quantity (EPQ) model the demand function of which is disrupted due to the presence of shortages. Assuming the demand function as complex in nature, we develop four types of doubt fuzzy sets namely proper doubt, harmful doubt, depressive doubt and confident doubt respectively and split the model into four sub-models accordingly. Based on new defuzzification method, we have introduced a new solution algorithm named dynamical doubt fuzzy optimization algorithm (DDFOA). By this new approach we have shown that with the application of learning vector by means of opportunity power/ fitness of various test functions the decision maker can achieve and avail the financial benefit as (s)he wishes to adopt. However, the concept of robust intelligent decision making has been discussed extensively through the numerical illustrations. Finally, sensitivity analysis, graphical illustrations are made to justify the proposed approach.

Dynamic analysis of biogas tank

Global warming is a phenomenon that makes us increasingly aware of the importance of protecting nature. Lack of drinking water and waste disposal belong to today’s biggest problem. This is the main reason why we try to recycle, use more renewable energy sources and treat waste ecologically. Drinking water tanks, sludge tanks for wastewater treatment and also tanks for biogas production, so-called fermenters, are becoming gradually more important. For built-up areas, respecting space usability, it is more appropriate to design tanks with a rectangular floor plan (so-called rectangular tanks). We can also use a system of rectangular tanks and thus achieve the most efficient use of space that is intended for them. In this article will be determined whether the proposed rectangular tank, intended for biogas production, has bearing capacity for dynamic loads. Construction of the tank itself must respect the design of the structure, as well as the building material, in order to prevent damage to its structure caused by the filling (it may also contain substances that could contaminate the environment and groundwater). This will ensure the integrity and load-bearing capacity of the tank and there is no risk of leakage. Selected tank is loaded with a standard response spectrum to see how it deforms, using finite element analysis in program ANSYS.

Mathematical modeling of spatial gas flow in nozzles of nontrivial geometry

Numerical modeling of the spatial gas flow in an adjustable nozzle with an asymmetric critical section caused by the overlap of a part of the flow area by a gas flow regulator has been carried out. The mathematical model is based on three-dimensional models of gas dynamics, the method of large particles is used for calculation. When describing the unsteady flow of an inviscid gas, the system of Euler equations is used, written for a computational rectangular plane, taking into account the function of nozzle geometry. The results of calculations of flow parameters along a nozzle path with a uniform outlet section and with an obliquely cut outlet nozzle are presented. Calculations were carried out for completely open critical sections and for half overlapped. For oblique cut nozzles, the overlap of the critical section from the side of the short part and from the side of the long part of the oblique nozzle is considered.

BEGINNING OF ISLAM IN CENTRAL ASIA: THE FIRST MOSQUE IN MERV, TURKMENISTAN

The first mosque in Central Asia was situated in the center of ancient Merv (Gyaur-kala) in the crossroad of two main streets, starting from four main gates of the town. The mosque was erected in the second half of the 7th century, after the Arab troops conquered Merv. The mosque became known as Beni Makhan Mosque. Using data from medieval sources and topographical works in the 1950s. M. Masson managed to find out the location of the mosque and began excavations, which were completed later in the 1960s by T. Khodjaniyazov. Been built of clay bricks, the first mosque was almost destroyed. The exact design of the mosque of that period is unknown. It was rebuilt in the 11th-12th centuries, in the time of the Seljuks. The corner minaret, the eastern and partially the southern walls, remained from the old building. The new mosque with three minarets has an incorrect rectangular plan.

Climate, buildings’ envelope design and energy patterns: improving energy performance of new buildings in Kuwait

PurposeThe two main contributing factors that control the overall buildings’ energy performance are the heating ventilation and air conditioning (HVAC) system and the envelope design. Environmental design guidelines that consider these two factors aim to lower energy consumption. However, they are regional and climate-sensitive. This study aims to investigate how three main buildings’ envelope design variables (orientation, compactness and window to wall ratio) impact the overall building’s energy consumption within Kuwait’s regional and climate conditions.Design/methodology/approachThis study simulate the energy consumption of typically shaped buildings by varying their geometry between a square to a rectangular floor plan. This study analyse the associated energy usage and provide early-stage envelope design guidance specific to the country’s conditions, to make informed decisions towards environmentally conscious buildings.FindingsThe analysed envelope variables have the potential to reduce energy consumption by 40%, and the possibility to reduce HVAC system capacity by 30%. In contrast to the general guidance in literature and standards, the simulation results demonstrate that less compact building forms perform on occasions better than the most compact ones.Originality/valueThe objective of this paper is to quantify the energy consumption rates for buildings located within the Arabian Peninsula, an under-studied region with potentially high interest considering three main envelope design variables. The buildings’ yearly energy consumption patterns are unique and suggest different envelope design considerations, compared to other regions with different climate conditions. This emphasises the importance of regional guidelines for the different factors associated with energy and buildings’ environmental performance.

HISTORIC AND CONSTRUCTIONAL ASPECTS OF STONE SCHOOLS IN GREECE: THE CASE OF THE ARISTOTLE MUNICIPALITY IN CHALKIDIKI

Historic schools, built during the end of the 19th – beginning of the 20th century, were evolved according to the wider socio-economic changes that took place at regional, national and international level. Their construction usually followed specific principles, governed by their functional role and structural safety requirements. In this study, the historical background of school buildings in Greece is given, in an effort to assess their evolution and physiognomy. To this direction, 14 historic school buildings, located in the Aristotle Municipality of Chalkidiki, N. Greece, were studied, taking into account their architectural and constructional characteristics. These buildings were erected from 1871 up to 1958 and are nowadays mostly used as elementary schools. In some cases, they are in second use or abandoned. They concerned 1 up to 3 storeys buildings, with rectangular ground plan, symmetrically organized around a main corridor. Their size and dimensions varied according to their capacity. From the beginning of the 30’s, supplementary elements of reinforced concrete (slabs, beams) were added, in combination with the existing building techniques. Nowadays, they are generally preserved in good state, due to the consecutive interventions taken place during their service life. However, their documentation and identification as heritage structures should be further assessed, in order to convey the tangible and intangible values they incorporate in the next generations.

Evidence of extreme events in wind-induced normal stress of the columns of low- and medium-rise building structures

We designed models for low- and medium-rise building structures with square and rectangular plans and tested the wind-induced normal stress of the building columns. We demonstrate the structures' normal stress response due to the wind load is non-Gaussian and shows evidence of extreme events, which are four to seven times larger than the mean standard deviation. We have estimated the probability distribution function to corroborate the long-tail nature of the extreme events, and randomness of the events is confirmed by plotting inter-event intervals and return maps. Further, the number of extreme events is calculated, which validates the exponentially decaying fit as a function of the number of standard deviations.

Source reconstruction of the 1969 Majene, Sulawesi earthquake and tsunami: A preliminary study

We studied the February 23rd, 1969 M7.0 Majene, Sulawesi earthquake and tsunami. It was followed by tsunami reported at five locations. At least 64 people were killed and severe damage on infrastructures were reported in Majene region. Based on damage data, we estimated that the maximum intensity of the earthquake was MMI VIII. Focal mechanisms, derived using first motion polarity analysis, indicated that the earthquake had a thrust mechanism. Furthermore, we built hypothetical earthquake scenarios based on a rectangular fault plane of 40 km × 20 km with a homogeneous slip model of 1.5 m. We run the Open Quake and the JAGURS code to validate the macroseismic and tsunami observation data, respectively. Our best-fitted earthquake model generates maximum intensity of 8+ which is in line with the reported macroseismic data. However, the maximum simulated tsunami height from all scenario earthquakes is 2.25 m which is smaller than the 4 m tsunami height observed at Pelattoang. The possibility of contribution of another mechanism to tsunami generation requires further investigation.

Analysis and Design of Stadium with Truss System and Shell Roof Subjected to Wind and Seismic Loading

In this paper Analysis and Design of different Structural elements of the football stadium are presented, with particular emphasis on the Combination of Steel Truss without and with Shell roof cover and its interȧction with the underlying reinforced concrete structures. The Football stadium considered for the study is of rectangular plan, with 85 m width and 140 m length and height of 19.5 m. The plan of Football Stadium is generated in AutoCAD 2016 software. The Stadium structure is composed of special moment – resisting framed. Wind velocity is taken as 39 mph and Seismic zone IV in this study. The proposed stadium is analysed using Equivȧlent static and dynamic ȧpproach by Reṣponse ṣpectrum ȧnd Time Hiṣtory ȧnȧlysis. In anȧlysing the ṣtructure, 21 load combinations are used. The grandstand ṣtructure is made of reinforced concrete and the roof is of ṣtructural steel using Pipe and Tube sections. Deȧd loȧdṣ, live loȧdṣ, wind ȧnd ṣeismic loȧdingṣ data are considered bȧsed on IS-875 (PART 1-3) 1987 ȧnd IS:1893 (Part 1):2016. IS456:2000 and SP16:1987 code is used for Design of R.C.C components such as Beȧm, Column, Seating Platform, Footing and IS 800:2007 code is used for Design of End Beȧring Plate connection with Truss member. Analysiṣ of truss and other elements is carried out with software program of Staad. Pro V8i SS6 and also the designs are carried out as per provisions of relevant Indian standards. On introduction of Shell-like roof for Open Stadium which is used not only to protect the Game from Glare of Sunshine and Rain but also appears unique and attractive. From the obtained results it is observed that the displacement due to Wind action in both X and Z direction reduces significantly by the introduction of Shell roof. Also, due to RSA and THA there is reduction in the displacement on introduction of Shell-like roof to an Open Stadium.

Shape dependence of wind pressure peak factor statistics in hyperbolic paraboloid roofs

The complex shape dependence of wind pressure’s peak factors (PFs) makes it difficult to predict their values for all geometries by using analytical models. Thus, experimental studies are necessary to validate available or new analytical models for each specific shape and geometry. Very little information is available in the literature for the hyperbolic paraboloid geometry, which is frequently used for cable net and membrane roofs that are particularly appropriate for covering large spans. This paper focuses on wind pressure’s PFs for this specific geometry. It presents a statistical analysis of experimental data taken from wind tunnel experiments on eight different geometries, obtained through the combinations of squared and rectangular plan shapes, high and low models, and two different curvatures of the roof parabolas. Roof zones for which a non-Gaussian behavior is predominant are identified. A comparison is made between PF statistics obtained experimentally and those estimated by the Davenport, modified Hermite, and Translated Peak Process (TPP) models, in terms of means and standard deviation errors estimated over the entire roofs. It is concluded that the modified Hermite and the TPP models provide the best estimates of the PF means and standard deviations, respectively.

Mutual inductance of two coaxial rectangular PCB coils incorporating magnetic layer

Abstract The wireless connection distance between the transmission and reception coils of printed circuit boards (PCB) influences the mutual inductance and affects circuit performance. In this study, the mutual inductance M of PCB coils was investigated, and two analytical methods were presented for calculating the mutual inductance between two coaxial rectangular planar PCB coils incorporating magnetic layer. The results were acquired through calculations by using the Neumann integral and Biot-Savart methods. The complete integral calculations and detailed demonstrations of the two methods are presented. The obtained formulas were introduced in some examples of coils with different number of turns. The analytical and experimental results were compared, and a strong agreement between them was observed.

Design analysis and test verification of a rigid-flexible, dual-mode coupling support structure for space-based rectangular curved prisms.

In view of the functional requirements of high reliability and stability support of optical components of space remote sensors, a rigid-flexible, dual-mode coupling support structure for space-based rectangular curved prisms (SRCPs) was designed. In-depth studies of the support principle and engineering realization of the SRCPs and optimization of the flexible adhesive structure were performed. Static and dynamic simulations were conducted on the mirror subassembly by means of finite element analysis, and test verification was also performed. The tests revealed that the surface shape error of the mirror subassembly after mechanical testing was 0.021λ, the displacement of the mirror body was 0.008 mm, the inclination angle was ∼0.8'', the mass of the mirror subassembly was 4.79 kg, the fundamental frequency was 283 Hz, and the maximum amplification of the total rms acceleration was 4.37. All indexes were superior to those of the design requirements. On this basis, bonding tests and mechanical tests of a rectangular curved prism reflector, a rectangular curved prism, and a rectangular plane reflector employing this proposed support structure were continued. The test results verified the reliability, stability, and universal applicability of the proposed rigid-flexible, dual-mode peripheral bonding support structure.

Opportunistic Control of a Slotted Hexagonal MIMO Structure Antenna for Lower Sub-6 GHz 5G Applications

In this research article, a high-performance and compact 2-port slotted hexagonal structure multiple-input multiple-output (MIMO) system is presented. This structure is designed by using novel technology that includes the hexagonal structure with a slotted rotate C-shape structure for obtaining better isolation parameters and commercial 5G applications. The overall design size is 40 × 26 mm2, which is effectively miniaturized at a resonant frequency of 3.5 GHz for a lower sub-6 GHz. Moreover, dual-band characteristics are achieved in the hexagonal MIMO structure by embedding an inverted C-shape structure and monopole rectangular ground planes on the bottom sides of the patches. In addition, the hexagonal MIMO structure shows better diversity performance and high isolation in terms of the Total Active Reflection Coefficient, Envelope Correlation Coefficient, channel capacity loss, mean effective gain, and diversity gain. For the slotted hexagonal MIMO structures established, a better trade-off is achieved and it is found that the MIMO design is the best candidate for applications of wireless communication.

Multi‐resonator gap‐coupled variations of microstrip antennas backed by rectangular slot cut ground plane

Novel gap-coupled variations of rectangular and circular microstrip antennas backed by rectangular slot cut ground plane are proposed. The slot on the ground plane below each of the patch, reduces the resonance frequency of the fundamental mode, thereby giving wideband response at the reduced frequency. With reference to the gap-coupled design at reduced frequency using the conventional ground plane, a slot cut ground plane design yields a reduction in the total patch area with higher BW and comparable gain values. On thinner Taconic substrate (h < 0.02λg), using rectangular and circular patches, the optimum result is obtained with parasitic patches gap-coupled along the two diagonal axis. In the rectangular patch design, bandwidth of 148 MHz (6.04%), peak gain of 9 dBi, for patch size reduction of 33.33% is achieved, whereas using the circular patches, these values are, 138 MHz (5.48%), 9.2 dBi and 38.4%, respectively. In all the proposed gap-coupled designs, for the maximum possible frequency reduction, BW and gain realized is higher as compared with the gap-coupled design with a normal ground plane.