Rectangular Type Research Articles

A Compact Planar Metamaterial Triple-Band Antenna with Complementary Closed-Ring Resonator

A compact planar triple-band metamaterial antenna is proposed and developed in this paper. Proposed metamaterial antenna consists of rectangular type complementary split ring resonator (CSRR) and meandered line inductor. Complementary closed ring resonator (CCRR) is introduced to achieve an extra resonant mode. This antenna offers triple-band operation at 2.02---2.14, 4.26---4.28, and 5.45---5.56 GHz with good impedance matching. These resonant modes are provided by the CSRR, CCRR and patch respectively. The electrical size of the antenna is 0.315 ?0 × 0.280 ?0 × 0.011 ?0. It achieves average antenna gain of 1.87, 2.90 and 4.13 dB at first, second and third bands respectively. Proposed antenna is suitable for modern wireless communication systems.

Quantitative Morphometric Analysis of Drainage Basins between Qusseir and Abu Dabbab Area, Red Sea Coast, Egypt using GIS and Remote Sensing Techniques

The coastal areas are considered of the promising areas for various types of sustainable development at present and in the future. As well as, this area occupies a large attention of the future planning for officials. The study area is located between Qusseir and Marsa Abu Dabbab along Red Sea coast. It is one of the most important areas. The study area is considered representing a promising and strategic target for urban and industrial expansions, as well as truism villages, but usually it is attacked by natural hazards, especially flash floods although rainfall is scarce in Eastern desert; it is well known for its flash floods with high velocity. The basin morphometric parameters, such as the linear, aerial and relief aspects of the basins, were determined using data (30 m resolution) from the ASTER DEM, Geographic Information System (GIS) and Remote-sensing data such as Landsat Thematic Mapper OLI. The study Linear, Relief and Arial aspects of drainage basins retrieved that, the area includes 25 basins, Wadi Ambagi basin is the largest basin in the study area (1538.24 km 2 ), while wadi Abu Sebekha is the smallest basin in the present study area (11.52 km 2 ). Primary results of this study were the determination that the basins have vast range stream order ranging from 3 rd to 7 th order drainage basins and a drainage pattern mainly of a parallel, dendritic, trellis and rectangular types. The observed drainage density in all basins range from 2.17 to 1.68 with an average is 1.86 km/km 2 . The average of elongation ratio (Re) for all the basins is 0.58, which mean that the most basins in the study area are elongated in shape but is relatively efficient in terms of the runoff discharge due to a large difference in slope. The bifurcation ratio ranges from 2.88 to 5.77, which indicates strong structural control of drainage patterns. Based on the slope map, it can be determined that the areas with high runoff and high erosion rates are those with steeper slopes. The area of rainwater accumulations and its close to mouths of wadis are more exposed to flash flooding. Based on the morphometric parameters which have a direct influence on flooding prone area, the flash flood hazard of sub-basins in the study area are classified into three groups; namely Extreme highly, moderately and Slightly hazard degree. However, most of the study area is environmentally nearly safe.

An optimised silicon piezoresistive microcantilever sensor for surface stress studies.

Surface stress is a versatile and efficient means to study various physical, chemical, biochemical and biological processes. This work focuses on developing high sensitive piezoresistive microcantilever designs to study surface stress. The cantilevers are made of silicon with rectangular holes at their base that also circumscribe a piezoresistor sensing element. To find the optimum design, the effects of change in cantilever width, rectangular hole length and type of dopant on mechanical properties like deflection, frequency and maximum stress are characterised using finite element analysis software. The surface stress sensitivity characteristics of the different cantilever designs is ascertained by applying a surface stress on their top surfaces. Results show that the sensitivity is increased by increasing the cantilever width as well as the length of the hole and the sensitivity of p-type designs is more than two times the n-type.

Design and Analysis of Printed Rectangular Micro Strip Antenna on Ferrite Material

study of Micro strip patch antenna is proposed by using artificial neural network. The geometry modelled for the study is rectangular patch type which will be mounted on ferrite substrate. The artificial neural network is used to study the modelled micro strip antenna by using synthesis and analytical approach. The relation between different parameter and dimensions of micro strip antenna are obtained. The patch dimension which is denoted by (W,L) are dependent of various input variable that can be further divided as resonant frequency(fr), height of dielectric substrate(h) and the dielectric constant of dielectric material(ex, ey). The results which are obtained using artificial neural network for the designed antenna are comparable with the result available in the patch antennas literature, theoretically as well as experimentally. The designed procedure is divided into synthesis and analysis which are forward and reverse side respectively. The designed procedure is used and ANN can be applied to the other geometry of antenna in general approach.

Design of a Naphtha Preheater for Hydrodesulphurization (HDS) Unit of Petroleum Naphtha with Given Feed Rate of 3500 Barrels per Day (BPD)

Oil refining and petrochemical manufacture involves extensive heating of hydrocarbon and other fluids. Depending on the temperature required, this heating is achieved either by steam or direct heating. In the latter case, the fluid under pressure is contained in tubes which are heated from the outside by direct exposure to flames. These heaters commonly take two forms, cylindrical heaters with one central burner, or a ring of burners in the base and the long rectangular type with many burners in a row along the floor, the latter are generally known as cabin heaters. This paper shows the design of one such furnace.

Comparative Study on the Characteristics of Film Flow with Different Corrugation Plates

The geometry of the packing structure can affect the flow pattern and considerably influence the mass transfer efficiency between liquid film and gas phase. Therefore, it is necessary to investigate the flow patterns and factors that determine the efficiency of mass transfer and heat transfer. In this study, different packing structures, namely, sinusoidal, triangular, and rectangular corrugated plates, are investigated. Computational fluid dynamic simulations based on the volume-of-fluid method are performed by using the open-source software OpenFOAM to study the liquid film flow over these corrugation plates. The free-surface area between the liquid and gas has been found to reach its maximum when the resonance phenomenon occurs. According to the simulation results the triangular corrugated plate has the largest free-surface area among the three types under the same conditions for a certain Reynolds number. The results also indicated that the pattern of film flow on the sinusoidal and triangular corrugated plates is similar; the rectangular type is not good as the other two types. It is useful to choose a suitable packing structure when considering the manufacturing process and cost The research results provide a theoretical basis for the study of heat and mass transfer used in industry applications.

Design of a Naphtha Preheater for Hydrodesulphurization (HDS) Unit of Petroleum Naphtha with Given Feed Rate of 3500 Barrels per Day (BPD)

Oil refining and petrochemical manufacture involves extensive heating of hydrocarbon and other fluids. Depending on the temperature required, this heating is achieved either by steam or direct heating. In the latter case, the fluid under pressure is contained in tubes which are heated from the outside by direct exposure to flames. These heaters commonly take two forms, cylindrical heaters with one central burner, or a ring of burners in the base and the long rectangular type with many burners in a row along the floor, the latter are generally known as cabin heaters. This paper shows the design of one such furnace.

A COMPACT DUAL-MODE METAMATERIAL-INSPIRED ANTENNA USING RECTANGULAR TYPE CSRR

In this paper a compact planar dual-mode metamaterial (MTM) antenna using rectangular type complementary split ring resonator (CSRR) is proposed. It is observed that an increase in series capacitance tends to decrease resonant frequency at which n = 1 mode is obtained in the proposed antenna. Zeroth order mode (ZOR) is obtained by means of rectangular type CSRR, tends to provide the miniaturized area. Dispersion relations are shown in order to characterize the metamaterial behavior by extracting the equivalent circuit parameters. The resonant frequency of the antenna is 2.14 GHz with input reflection coefficient up to −45 dB. The electrical size of the proposed MTM antenna is 0.321λ0 × 0.285λ0 × 0.011λ0. ZOR mode is observed at 1.15 GHz although the proposed antenna is operated at 2.14 GHz. Furthermore, it achieves simulated antenna gain of 2.60 dB with 70% radiation efficiency. In order to verify the simulation results of antenna, a prototype is fabricated and measured.

Visualized measurement of the electric field in large aperture LiNbO3 crystal by digital holographic interferometry

The electric field distribution in LiNbO3 crystal under different electrode shape is presented by using the digital holographic interferometry. Three configurations of phase modulator including the rectangular electrode type, single-triangle electrode type, and dual-triangle electrode type are performed in this experiment. The nonuniform electric field distribution in these phase modulators are observed and the electric field increases with voltage increasing. The digital holographic interferometry with high electro-optic effect improves the measurement precision. The digital holographic interferometry provides an effective way for studying the electric field distribution. Such in situ quantitative analysis of electric field distribution is a key to optimizing electrode shape.

Uniqueness in inverse elastic scattering from unbounded rigid surfaces of rectangular type

Consider the two-dimensional inverse elastic scattering problem of recovering a piecewise linear rigid rough or periodic surface of rectangular type for which the neighboring line segments are always perpendicular. We prove the global uniqueness with at most two incident elastic plane waves by using near-field data. If the Lame constants satisfy a certain condition, then the data of a single plane wave is sufficient to imply the uniqueness. Our proof is based on a transcendental equation for the Navier equation, which is derived from the expansion of analytic solutions to the Helmholtz equation. The uniqueness results apply also to an inverse scattering problem for non-convex bounded rigid bodies of rectangular type.

Fabrication of Cellulose Nanocrystals from Agricultural Compost

ABSTRACTCellulose nanocrystals have emerged as replacements for man-made fibers to fabricate environmentally friendly green products. In this work, cellulose nanocrystals (CNCs) of mixed morphology were synthesized by acid hydrolysis of compost using sulfuric acid. Compost, an agro-based biomass feedstock, procured from water hyacinth (Eichhornia crassipes), cow dung, and saw dust (8:1:1) was utilized for the extraction of cellulose, followed by synthesis of CNCs. Compost was prepared using a rotary drum composter and was utilized for the production of CNCs. A two-step procedure for the extraction of CNCs was studied. Initial chemical treatments, including alkali treatment and bleaching, led to the gradual removal of lignin and hemicellulose, while the subsequent sulphuric acid (40%) hydrolysis step yields CNCs in an aqueous suspension. The synthesized CNCs have been studied by Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and particle size analyzer. The morphology and dimension of nanofibrils were studied by scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) techniques, which showed mixed morphology of rectangular cone type and spherical dimensions. Fabrication of such mixed morphology was found to be dependent on the selected biomass. The trace of metal elements present in the biomass was investigated by scanning electron microscopy-energy dispersive X-ray (SEM-EDX). We report a cost effective and feasible approach of utilizing inexpensive bioresources for production of value added products like CNCs, which could find potential application in the fields of healthcare, biomedical engineering, packaging, etc.

Dispersion curves of 2D rods with complex cross-sections: double orthogonal polynomial approach

Orthogonal polynomial series approach has been used to analyze the guided wave propagation in structures for about 20 years. These structures have always one infinite dimension in the waveguiding direction and, sometimes a regular finite cross-section (axially infinite solid or hollow cylinder for instance) and mostly often an infinite cross-section (infinite flat plate or half-space for instance). This paper presents a double orthogonal polynomial approach to investigate guided wave propagation in structures with only one infinite dimension in the waveguiding direction and a finite but complicated cross-sectional geometries as, rectangular type, L-type, 工-type and 回-type cross-sections. Through a numerical comparison with results available in literature, the validity of the extended polynomial approach is illustrated for a specific geometry. The dispersion properties of guided waves in rods with complex cross-sections as mentioned above are discussed.

CFD investigation of flow in the MATIS-H test facility

Abstract In this paper steps of calculations for a bare rod bundle and so-called swirl type spacer grid are showed and the effects of choice of model details are examined. The modeled pin bundle and spacer grid geometry are related to rectangular western type PWR fuel assemblies. First a CFD model has been developed for a subchannel of the MATIS-H test facility in order to carry out a mesh independence study. Based on the results a model for the half cross-section of the test bundle has been developed and calculations are carried out with different turbulence models. Translational periodicity is applied in axial direction in order to calculate a fully developed flow, which will be used as inlet boundary condition for spacer grid calculations. Results are compared with LDA (Laser Doppler Anemometry) measurements published in the frame of the OECD NEA MATIS-H benchmark. As a last step a model for rod bundle incorporating swirl type spacer grid is developed and calculations are carried out with different turbulence models using the results of the bare rod bundle simulations as inlet boundary conditions.

New design and mapping of sonochemical reactor operating at capacity of 72L

Abstract Understanding of the distribution of cavitational activity helps in achieving efficient design and scale up of sonochemical reactors. The experimental investigation of the mapping of cavitational activity has been performed in the present work in a large scale sonochemical reactor operating at 40 kHz with a capacity of 72 L. The reactor is a multiple transducer rectangular flow cell type reactor operating at variable power dissipation levels with maximum rating of 2400 W. Two chemical dosimeters have been used for the mapping studies as potassium iodide and dichlorvos degradation for the quantification of cavitational activity. The calorimetric power measurement has also been performed to quantify the actual power dissipation in the liquid medium. Effect of input power on the cavitational activity has been investigated at different locations in the ultrasonic flow cell. The obtained results have established that there is good agreement between the two chemical dosimeters. Also the cavitational activity distribution was fairly uniform as compared to other conventional designs based on the use of single transducer. It has been also confirmed that the novel method based on dichlorvos degradation adapted in the present work can be used as one of the mapping techniques to establish better correspondence with the wastewater treatment applications due to similarity in the controlling mechanisms. Overall, the new design presented in the work gives uniform distribution of the cavitational activity to a greater extent and can be a useful design for commercial scale installations.

Dynamic analysis of linear viscoelastic cylindrical and conical helicoidal rods using the mixed FEM

Abstract The objective of this study is to investigate the influence of the rotary inertia on dynamic behavior of linear viscoelastic cylindrical and conical helixes by means of the Laplace transform-mixed finite element formulation and solution. The element matrix is based on the Timoshenko beam theory. The influence of rotary inertias is considered in the dynamic analysis, which is original in the literature. Rectangular, sine and step type of impulsive loads are applied on helices having rectangular cross-sections with various aspect ratios. The Kelvin and standard models are used for defining the linear viscoelastic material behavior; and by means of the correspondence principle (the elastic-viscoelastic analogy), the material parameters are replaced with their complex counterparts in the Laplace domain. The analysis is carried out in the Laplace domain and the results are transformed back to time space numerically by modified Durbin׳s algorithm. First, the solution algorithm is verified using the existing open sources in the literature and afterwards some benchmark examples such as conical viscoelastic rods are handled.

Compact Planar Monopole Antenna with Dual Band Notched Characteristics Using T-Shaped Stub and Rectangular Mushroom Type Electromagnetic Band Gap Structure for UWB and Bluetooth Applications

In this paper, an ultra-wideband (UWB) antenna with dual band-notched characteristics is proposed. The proposed antenna also covers ISM (Industrial, Scientific, and Medical)/Bluetooth band. The antenna consists of a microstrip fed truncated U-shaped patch, T-shaped stub, rectangular mushroom type electromagnetic band gap structures (EBG), and partial ground plane. To mitigate the problem of interference due to standard narrow bands (like wireless interoperability microwave access (WiMAX) and wireless local area network (WLAN)) lie in the range of UWB, dual band notched characteristics is introduced. The WiMAX and WLAN band notched characteristics are realized by introducing a T-shaped stub and rectangular mushroom type EBG structures, respectively. The proposed antenna is printed on a 1.6 mm thick FR4 substrate with relative permittivity $$(\upvarepsilon _{\mathrm{r}})$$ ( ? r ) 4.4 and the size of actual antenna is $$36 \times 40\hbox { mm}^{2}$$ 36 × 40 mm 2 . The measured results shows that the proposed antenna attains a wide impedance bandwidth $$(\hbox {VSWR} \le 2)$$ ( VSWR ≤ 2 ) from 2.35 to 11.6 GHz with dual band notched characteristics from 3.29 to 3.9 GHz and 5.1 to 5.85 GHz with stable radiation patterns. The time domain behaviors of the proposed antenna is also analyzed for pulse handling capability.

Development of a beam stop array system with dual scan mode for scatter correction of cone-beam CT

A beam stop array (BSA) is widely used to estimate the scatter distribution of cone-beam computed tomography (CT) experimentally. A rectangular BSA, which is the most generally used, produces a penumbra region at the edge of the grid on the projection image. The penumbra region can be the cause of an inaccurate scatter estimate and loss of image data. In this study, two types of BSAs have been designed and developed, a linear BSA (l-BSA), which is a simple rectangular type, and a curved BSA (c-BSA) to avoid the penumbra effect. A Monte Carlo simulation was performed to determine the thickness and the material of beam stop arrays. The particle tracking technique of MCNP5 code was used to analyze the accuracy of the scatter distribution acquired by the beam stop arrays. The improvement in the image quality was analyzed by using an in-house phantom, a simple type CT phantom, and a humanoid phantom. How the curved beam stop array improved the penumbra effect was also analyzed in a large field of view. The additional dose caused by a dual scan was analyzed by using a Monte Carlo simulation and experiment. The accuracies of the scatter estimates were 83.4% for the c-BSA and 90.4% for the l-BSA. The c-BSA compensated the penumbra effect effectively while the l-BSA had a severe penumbra region in the partial projection image in a large field of view. Contrasts were improved by 24.8 (air-PMMA), 55.8 (Teflon-PMMA), and 81.7% (water-PMMA) for the c-BSA and 11.1 (air-PMMA), 44.1 (Teflon-PMMA), and 82.2% (water-PMMA) for the l-BSA by scatter correction. After noise suppression, the contrast-to-noise ratios were improved by 2.7–4.1 times for the c-BSA and 3.5–5.3 times for the l-BSA. Uniformities were also improved by up to 10 times for the c-BSA and 12 times for the l-BSA. The quality of the humanoid phantom image was also improved after the scatter correction. Consequently, the c-BSA can improve the image quality of cone-beam CT and compensate for the penumbra effect without an additional dose of radiation.

Analysis of the biomass gasification-based shape of the crematory’s secondary chamber by using Computational Fluid Dynamics

This paper describes the simulation result of biomass gasification-based crematory's secondary combustion chamber via CFD analysis. The chamber models, which were rectangular and cylinder type, were implemented, whereas ANSYS FLUENT with standard k-omega viscous model and SIMPLE algorithm were taken place. The results show that an average residence time of gas and particle if simulating by using rectangular chamber displays as 2 and 3 second, respectively, whereas the average residence time of cylinder chamber type presents 2 second for particle and 4 second for gas. Furthermore, the residence time of cylinder chamber type can be increased by lengthening the chamber's height, which the benefits, such as efficient pollution control, will be earned.

Knudsen diffusion in channels and networks

Knudsen diffusion is approximately valid when the channel diameters are much larger than molecular diameters, adsorption forces are weak or negligible, and the only obstacles are molecule–wall collisions. The ray lengths between walls are distributed over an enormous range, and there is no upper bound for occasional extreme outliers. A Monte Carlo simulation produces an enormous range in the distribution of diffusivities, which follows a log-normal distribution. A reasonably accurate estimation of diffusivity requires more than 10,000 runs.The principal types of one-dimensional channels are the zig-zag channels and the connected cavities, and they have diffusivities that are much lower than the straight channels. The principal cause is lower vista which reduces the extreme lengths of the outlier rays, and the contributing causes are tortuosity, and negative correlation which increases the probability that consecutive steps are in opposite directions. The principal types of two-dimensional channels investigated are: rectangular, oblique, brick, hexagon, and straight-sinusoid or MFI type. They give rise to highly anisotropic diffusion tensors.

Long Wavelength Plasmonic Absorption Enhancement in Silicon Using Optical Lithography Compatible Core-Shell-Type Nanowires

Plasmonic properties of rectangular core-shell type nanowires embedded in thin film silicon solar cell structure were characterized using FDTD simulations. Plasmon resonance of these nanowires showed tunability from nm. However this absorption was significantly smaller than the Ohmic loss in the silver shell due to very low near-bandgap absorption properties of silicon. Prospect of improving enhanced absorption in silicon to Ohmic loss ratio by utilizing dual capability of these nanowires in boosting impurity photovoltaic effect and efficient extraction of the photogenerated carriers was discussed. Our results indicate that high volume fabrication capacity of optical lithography techniques can be utilized for plasmonic absorption enhancement in thin film silicon solar cells over the entire long wavelength range of solar radiation.