Asymmetric Arrangement Research Articles

A Dual-band Circularly-polarized Printed Monopole Antenna for Wi-Fi and WiMAX Applications

This paper presents a rectangular-shaped printed monopole antenna with circular polarization for Wi-Fi (2.4–2.484 GHz) and WiMAX (3.3-3.7 GHz) bands. The antenna relies on asymmetric arrangement of the patch with respect to the microstrip feed, in order to generate circular polarization. Dual-band (Wi-Fi and WiMAX) operation is enabled by inserting a slit in the corner of the ground plane. Simulation results show a bandwidth increase of 15.9% (2.2–2.58 GHz) for Wi-Fi, and of 24.16% (3.13–3.99 GHz) for WiMAX applications. Furthermore, beamwidths at the axial ratio of 3 dB equal 48˚ and 51˚ for the x-z plane and y-z planes, respectively.

Effect of Different Nozzle Arrangements on Gas–solid Flow Characteristics of a New Air Distribution System Circulating Fluidized Bed

ABSTRACT The air distribution system was one of the key devices that affects solid flow characteristics in circulating fluidized bed (CFB). Different air distribution systems have an influence on gas–solid flow uniformity, solids velocity, and concentration. In the conventional CFB, the air distribution system which composed of air chamber and distributor was placed on the bottom of the reactor. In this paper, an atmospheric circulating fluidized bed gasifier (AT-CFBG) was examined. The chamber and distributor of CFB was canceled and which was replaced by six nozzles with asymmetrical and symmetrical arrangement that mounted on the bottom of the furnace. A cold test was established at a scale of 1:15, the optical fiber was used to measure solids concentrations and velocities in the furnace under the asymmetrical and the symmetrical arrangement. The results showed that the asymmetrical arrangement has a better uniform velocity profile and has a higher solids concentration than those of the symmetrical arrangement. And it also has a stable solids circulation and a higher solids circulation rate (0.37 kg/h) than those of the symmetrical arrangement (0.34 kg/h).

Studying the load of the upgraded traction frame suspension mechanism of the DZk-250 collection of the motor grader

Problem. Motor grader is one of the leading machines in the road construction industry. The feature of the design is an asymmetric arrangement of the traction frame suspension mechanism (TFSM) with respect to the longitudinal axis. This results in uneven rebalance between the slave hydrocylinder and reduces the efficiency of motor graders. Goal. The purpose of the work is to study the load of the slave hydrocylinder of the modernized TFSM using a virtual model created on the basis of the Autodesk Inventor Professional software package and the MATLAB software product. Methodology . The external load is represented as a single load (1 kN). This mechanism works as follows: during the work, the operator moves the slider along the guide rail of the wedge-shaped form, using an additional hydrocylinder moving the position of the rod of the hydrocylinder the drawbar shift in the transverse plane of the motor grader movement. Results . The use of the proposed mechanism allows changing the position of the anchor point of the drawbar shift to the side, predicting the rational reduction of uneven load of the TFSM design (an average of 2.7 times) and achieving an even distribution of forces between the three hydrocylinders. The proposed mechanism can be installed on a motor grader of any class. Originality . The main recommendation is that the grader blade is operated as shown in figure 4.

Front of pack symmetry influences visual attention

Abstract: This paper investigates the impact on visual attention of a symmetrical versus an asymmetrical arrangement on the front of pack (FOP) of FMCGs. The authors conducted a laboratory experiment using an eye-tracking method. Two FOPs were designed for each product category (orange juice, chocolate bars, pasta and biscuits). In one version the information items were arranged symmetrically around a vertical axis, and in another they were asymmetrically arranged. The findings show that symmetry influences viewers' attention, first by influencing the visual attention paid to the entire FOP and, second, by its impact on the capacity of specific FOP areas to capture and hold visual attention.

Dual Light and Temperature Responsive Micrometer-Sized Structural Color Actuators.

Externally induced color- and shape-changes in micrometer-sized objects are of great interest in novel application fields such as optofluidics and microrobotics. In this work, light and temperature responsive micrometer-sized structural color actuators based on cholesteric liquid-crystalline (CLC) polymer particles are presented. The particles are synthesized by suspension polymerization using a reactive CLC monomer mixture having a light responsive azobenzene dye. The particles exhibit anisotropic spot-like and arc-like reflective colored domains ranging from red to blue. Electron microscopy reveals a multidirectional asymmetric arrangement of the cholesteric layers in the particles and numerical simulations elucidate the anisotropic optical properties. Upon light exposure, the particles show reversible asymmetric shape deformations combined with structural color changes. When the temperature is increased above the liquid crystal-isotropic phase transition temperature of the particles, the deformation is followed by a reduction or disappearance of the reflection. Such dual light and temperature responsive structural color actuators are interesting for a variety of micrometer-sized devices.

Hybridization Effects of S-glass fiber on Charpy impact resistance of carbon/aramid fiber reinforced epoxy composite laminates

The objective of the present research work is to investigate the Charpy impact behavior of intraply hybrid carbon/aramid fabric layers with S-glass fabric layers composite laminates for asymmetric and symmetric arrangements. The hybridization effects on Charpy impact characteristics for carbon/aramid with S-glass hybrid composite laminates were compared with those of carbon/aramid/epoxy composite laminates and S-glass/epoxy composite laminates. Deformation degree, impact energy and impact strength were strongly affected by the position and number of carbon/aramid layers in addition to the impact side direction due to variation of impact properties between carbon/aramid fibers and S-glass fibers. Using S-glass layers instead of carbon/aramid layers exhibited decreasing in the deformation level particularly for carbon/aramid side impact in addition to improve the impact strength of the hybrid composite.

Development and growth of the pectoral girdle and fin skeleton in the extant coelacanth Latimeria chalumnae.

The monobasal pectoral fins of living coelacanths and lungfishes are homologous to the forelimbs of tetrapods and are thus critical to investigate the origin thereof. However, it remains unclear whether the similarity in the asymmetrical endoskeletal arrangement of the pectoral fins of coelacanths reflects the evolution of the pectoral appendages in sarcopterygians. Here, we describe for the first time the development of the pectoral fin and shoulder girdle in the extant coelacanth Latimeria chalumnae, based on the tomographic acquisition of a growth series. The pectoral girdle and pectoral fin endoskeleton are formed early in development with a radially outward growth of the endoskeletal elements. The visualization of the pectoral girdle during development shows a reorientation of the girdle between the fetus and pup 1 stages, creating a contact between the scapulocoracoids and the clavicles in the ventro-medial region. Moreover, we observed a splitting of the pre- and post-axial cartilaginous plates in respectively pre-axial radials and accessory elements on one hand, and in post-axial accessory elements on the other hand. However, the mechanisms involved in the splitting of the cartilaginous plates appear different from those involved in the formation of radials in actinopterygians. Our results show a proportional reduction of the proximal pre-axial radial of the fin, rendering the external morphology of the fin more lobe-shaped, and a spatial reorganization of elements resulting from the fragmentation of the two cartilaginous plates. Latimeria development hence supports previous interpretations of the asymmetrical pectoral fin skeleton as being plesiomorphic for coelacanths and sarcopterygians.

A three-dimensional noncentrosymmetric zinc-4,4′,4′'-nitrilotribenzoate structure exhibiting second-harmonic generation responses

A coordination polymer [Zn(H-ntb)]n (1) based on the tritopic carboxylate linker of 4,4′,4′'-nitrilotribenzoate (H3-ntb) was reported here. Compound 1 crystallizes in a polar space group of Pca21 and contains two-dimensional layers formed from the left- and right-handed helical chains pillared by the benzoate moieties to give a three-dimensional structure. The present compound 1 features a noncentrosymmetric structure and displays a strong phase-matchable second-harmonic-generation (SHG) response of 1.2 times that of potassium dihydrogen phosphate (KDP). The inherent polarity of the 4,4′,4′'-nitrilotribenzoate and distortive [ZnO4] tetrahedrons as well as the asymmetric arrangement of the building blocks are responsible for the SHG activity for 1.

Abrogation of Article 370: can the president act without the recommendation of the constituent assembly?

ABSTRACTArticle 370 of the Constitution of India 1950, as it stood till recently, restricted the Parliament’s legislative powers over the erstwhile state of Jammu and Kashmir (“J&K”). The provision, which was recently abrogated was under challenge even prior to that. In 2018, a challenge to its constitutionality was mounted on the ground that it was meant to be a temporary arrangement. In this paper, it is argued that the attempts to abrogate the provision without the recommendation of a constituent assembly for J&K is constitutionally suspect. This has both textual and normative support. Textually, the asymmetrical federal arrangement embodied in Article 370 as well as the procedural limitations mean that it is not open to the Union to abrogate it unilaterally. Normatively too, a temporary provision such as Article 370 may only be abrogated if its detractors can garner sufficient political support in the form of a constituent assembly, which has not yet been achieved.

An investigation of the effect of make-up air velocity on smoke layer height with asymmetric openings and rotational air flow in atrium fires

The results of full-scale tests of smoke interface height in atrium fires with different make-up air velocities and opening arrangements, including asymmetric openings and openings that resulted in rotational air flows, are presented in this paper. The non-symmetric opening arrangements included openings on 3 sides of the atrium, 2 adjacent sides and 1 side. Make-up air velocities of 1, 1.5 and 2 m/s and fire sizes of 1, 2 and 5-MW were considered. Temperature was recorded along the height of the atrium by setting up thermocouple trees, and the temperatures measurements were used to determine the experimental smoke interface height using the N-percentage method. Predicted smoke layer height from the atrium plume correlation is compared with the full-scale test data. The results show that even a 1 m/s make-up air velocity can cause a significant decrease in the smoke interface height in the case of an asymmetric opening arrangement and rotational air flows in the atrium. The full-scale test data are used to propose a correlation to calculate the reduction of smoke interface height for the design of smoke exhaust systems in atria.

Tetrameric Aβ40 and Aβ42 β-Barrel Structures by Extensive Atomistic Simulations. II. In Aqueous Solution.

Alzheimer's disease (AD) is characterized by the accumulation of extracellular Aβ42 and Aβ40 oligomers and plaques. In a recent computational study, we found that the presence of the residues I41 and A42 increases significantly the propensity of Aβ to form a tetrameric β-barrel structure in a bilayer mimicking a neuronal membrane. In this work, we have determined the propensity of the two Aβ proteins to form tetrameric β-barrel structures in aqueous solution using four atomistic protein fields, that is, Amber99SB-ILDN/TIP3P, OPLS/TIP3P, CHARMM36m/TIP3P-modified, and Amber99SB/DISP. Extensive replica exchange molecular dynamics simulations make it clear that a β-barrel, made of two distinct β-hairpin motifs and an asymmetric arrangement of eight antiparallel β-strands with an inner pore diameter of 0.7 nm, exists transiently for Aβ42 peptide, but this is less the case for Aβ40 peptide, due to the change of the CHC-CHC and the Cter-Cter interfaces. This study has several implications in AD.

A New Asymmetric Planar V-Shaped Magnet Arrangement for A Linear PM Synchronous Motor

In this paper, a new asymmetric planar V-shaped magnet arrangement for a linear PM synchronous motor is proposed. Several magnet arrangements for the track of the proposed linear permanent magnet (PM) synchronous motor such as un-skewed magnets, conventional magnet skew, and V-shaped planar magnets have been investigated. The performance results of the linear motor with skewed magnets are compared to those of previously designed PM linear synchronous motor with conventional un-skewed rectangular-shaped (CuSRS) magnets. The forcer is kept the same for all track structures and a thorough comparison is provided for low detent force and low force ripple with the CuSRS and proposed planar V-shaped magnet skew approaches.

Torque ripple improvement for ferrite-assisted synchronous reluctance motor by using asymmetric flux-barrier arrangement

Torque ripple improvement for ferrite-assisted synchronous reluctance motor by using asymmetric flux-barrier arrangement

Energetics and electronic structures of MoS2 nanoribbons

We study the energetics and electronic structures of MoS2 nanoribbons with clean armchair, chiral, and zigzag edges by conducting the first-principle total energy calculations based on the density functional theory. Our calculations showed that the nanoribbon with zigzag edges is the most stable among the ribbons studied here. The ribbons with armchair or near armchair edges are semiconductors with a direct band gap at the Γ point, owing to the large edge relaxation reducing the unsaturated nature of edge atoms, while the ribbons with zigzag and near zigzag edges are metals with the finite density of state at the Fermi level. According to the asymmetric atomic arrangement in ribbons with the chiral and zigzag edges, they have polarity across the ribbon, which monotonically increase with increasing edge angle.

On the rationing the parameters of asymmetric loading of all-purpose freight cars

Due to the presence in the operating fleet of freight cars with a base of over 10 m, as well as the practical impossibility of symmetrically placing loads with a weight corresponding to the nominal carrying capacity on open rolling stock, adjustments to the existing asymmetrical loading standards are necessary. To this end, it is proposed to apply a comprehensive methodology for determining the allowable parameters of asymmetrical placement of freights, based on a combination of strength criteria of the bearing elements of cars, ensuring the normative level of dynamic qualities and stability of the loaded car. The article provides an example of determining the permissible parameters of the joint lateral and longitudinal displacement of the total center of gravity of the car (ЦТгр°), loaded to the nominal capacity. According to the results of the studies to determine the allowable values of longitudinal and lateral displacement ЦТгр° with unbalanced placement within the loading platform of the car, including the presence of a joint displacement, it was found that to improve the efficiency of using freight cars with an increased base, it is advisable to update the current offset standards of ЦТгр°. It is recommended to take the values of longitudinal displacement ЦТгр° for cars with a body base of 14.6 and 19.0 m respectively 1.46 and 2.11 m for freight with a total weight of 50 tons; 1.10 and 1.43 m for freight with a total weight of 60 tons; 0.22 and 0.28 m – for freight with a total weight of 67 tons. When placing freights with a total weight of over 67 tons with a height of center of gravity of 2.0–2.2 m on 4-axle freight cars with an axle load of 230.5 kN without limiting the permissible driving speeds, it is recommended to use a graphical method for determining the joint (longitudinal and transverse) displacement ЦТгр°. With an increase in the joint displacement parameters ЦТгр°, it will be necessary to limit the speed of the car in the curved sections of the track and to the lateral direction on the turnouts.

Efficiency of application of various layout arrangements of oil-gas burners in thermal power plant boilers

The necessary intensity of burning and completeness of fuel burning out in furnace volume are reached by the correct supply organization and the subsequent mixture of fuel with secondary air that is provided with burner devices. Experimental research of fuel oil and gas combustion efficiency in boiler furnaces of thermal power plant has shown that, the peripheral axial twist executed in the form of two channels with axial scapular air rotator is preferable. The combined gas supply is perspective: tubular peripheral and pilot central. For fuel oil combustion at large expenses the most effective burning is reached due to application of steam-mechanical nozzles which main lack is the considerable length of a torch. The two-tiered arrangement of burners in boiler at combustion of gas and fuel oil is more effective, in comparison with single-tier, both at the counter direction, and at unilateral frontal. For increasing the efficiency of combustion of fuel at some burners types in a boiler furnace the ascending vertical rotation of a torch can be created by the asymmetrical counter arrangement of burners of the first and second tiers. Use of the smoke exhauster of gases recirculation for reduction of harmful emissions of nitrogen oxides with boilers flue gases gives bigger effect in comparison with optimization of the choice of a layout arrangement of burners and parameter of a twist.

Transmission Attenuation of 110kv Asymmetric Transmission Lines Based on Measured Data

The characteristic of traveling wave transmission has great influence on the location precision of the fault point. In order to accurately evaluate the transmission and attenuation characteristic of actual traveling wave on transmission lines, a typical asymmetric arrangement 110kV transmission line is selected as the research object. First, the parameters of the transmission line are calculated, and the traveling wave decoupling algorithm is derived. Then, the traveling wave current collected by the distributed traveling wave monitoring system on the line is analyzed. The results show that for a short distance asymmetric 110kV line, it can be decoupled by the conventional decoupling balance line method, and the coupling component ratio is less than 2% after decoupling. With the increase of transmission distance, the attenuation degree of traveling wave increases. When the transmission distance is 60km, the attenuation of line mode is 21.2% and the zero mode attenuation is 50.4%.

Multihole dielectric barrier discharge with asymmetric electrode arrangement in water and application to sterilization of aqua pathogens

To make aquaculture more environmentally and economically sustainable, novel water treatment technologies are urgently required. Therefore, in this study, a novel multihole dielectric barrier discharge (MH-DBD) plasma system submerged in water was investigated to sterilize aquaculture pathogens. The plumes from the DBD plasma directly contact water through multiple holes installed on an outer dielectric of an asymmetric coaxial DBD. The MH-DBD plasma in Vibrio harveyi sterilization showed inactivation performance higher than 2 log reduction, compared to coaxial DBD plasma without direct contact with water. From the plasma emission lines, we identified the chemically active species resulting from water dissociation. The aqua pathogens tested in the experiments were of five types containing Edwardsiella tarda, which causes lethal diseases in aquaculture populations; the MH-DBD plasma showed high sterilization performance over 6.5–7.5 log reduction under specific conditions. Consequently, we believe that the MH-DBD plasma can be an effective water treatment tool not only to sterilize fish pathogens in aquaculture but also to decontaminate waste water through plasma-based oxidation processes.

Design Optimization of a Permanent-Magnet Saturated-Core Fault-Current Limiter

Designs of saturated-cores fault current limiters (FCLs) usually implement conducting or superconducting DC coils serving to saturate the magnetic cores during nominal grid performance. The use of coils adds significantly to the operational cost of the system, consuming energy, and requiring maintenance. A derivative of the saturated-cores FCL is a design implementing permanent magnets as an alternative to the DC coils, eliminating practically all maintenance due to its entirely passive components. There are, however, various challenges such as the need to reach deep saturation with the currently available permanent magnets as well as the complications involved in the assembly process due to very powerful magnetic forces between the magnets and the cores. This paper presents several concepts, achieved by extensive magnetic simulations and verified experimentally, that help in maximizing the core saturation of the PMFCL (Permanent Magnet FCL), including optimization of the permanent magnet to core surface ratios and asymmetrical placement of the permanent magnets, both creating an increase in the cores’ magnetic flux at crucial points. In addition, we point to the importance of splitting the AC coils to leave the center core point exposed to best utilize their variable inductance parameters. This paper also describes the stages of design and assembly of a laboratory-scale single phase prototype model with the proposed PMFCL design recommendations, as well as an analysis of real-time results obtained while connecting this prototype to a 220 V grid during nominal and fault states.

Structural, Kinetic, and Mechanistic Analysis of an Asymmetric 4-Oxalocrotonate Tautomerase Trimer.

A 4-oxalocrotonate tautomerase (4-OT) trimer has been isolated from Burkholderia lata, and a kinetic, mechanistic, and structural analysis has been performed. The enzyme is the third described oligomer state for 4-OT along with a homo- and heterohexamer. The 4-OT trimer is part of a small subset of sequences (133 sequences) within the 4-OT subgroup of the tautomerase superfamily (TSF). The TSF has two distinct features: members are composed of a single β-α-β unit (homo- and heterohexamer) or two consecutively joined β-α-β units (trimer) and generally have a catalytic amino-terminal proline. The enzyme, designated as fused 4-OT, functions as a 4-OT where the active site groups (Pro-1, Arg-39, Arg-76, Phe-115, Arg-127) mirror those in the canonical 4-OT from Pseudomonas putida mt-2. Inactivation by 2-oxo-3-pentynoate suggests that Pro-1 of fused 4-OT has a low p Ka enabling the prolyl nitrogen to function as a general base. A remarkable feature of the fused 4-OT is the absence of P3 rotational symmetry in the structure (1.5 Å resolution). The asymmetric arrangement of the trimer is not due to the fusion of the two β-α-β building blocks because an engineered "unfused" variant that breaks the covalent bond between the two units (to generate a heterohexamer) assumes the same asymmetric oligomerization state. It remains unknown how the different active site configurations contribute to the observed overall activities and whether the asymmetry has a biological purpose or role in the evolution of TSF members.