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In this paper, a novel multiband coplanar waveguide-fed slotted transparent antenna is presented. The structural design of the radiating element is based on the semicircular curves in the form of slots on the patch to achieve multi-band characteristics with improved bandwidth. The overall structure having a size of λ0/2.67 × λ0/2.11 achieves transparency and a lightweight due to the presence of Plexiglas as a substrate material and AgHT-8 as a conductive material including the circular slotted patch and related CPW feeding line at the center frequency of the lowest operation band. The proposed antenna has the multiband operation characteristics with the center frequencies of 2.58 GHz, 3.67 GHz, 6.2 GHz having the impedance bandwidth of 19.84% (2.27—2.77 GHz), 1.76% (3.61—3.74 GHz) and 53.58% (4.50–7.79 GHz) respectively. The agreement between the numerical computation and measurement results of RF performance characteristics point out the technical potential of the proposed optically transparent antenna for short range multiband versatile wireless applications. [ABSTRACT FROM AUTHOR]

In marine and coastal radar applications it is usual to find antennas consisting of a slotted waveguide antenna and a horn antenna. To increase the effectiveness of the cuban coastal surveillance system, it is proposed to modify the AU11-07N slotted waveguide antenna of the Navy-Radar 4000 based on the design of an optimal pyramidal horn antenna, causing the half power beamwidth to be reduced by half in the vertical plane. To achieve the objective, the original antenna is measured and modeled to then simulate it in the Ansoft HFSS software and compare it with the data from the radar manual. Then, the original antenna is modified based on the design of an optimal pyramidal horn, simulated and adjusted to the final dimensions based on the variation in the length of its plates. With the proposed modification, the half power beamwidth is achieved for the vertical plane of 11,30o and for the horizontal plane of 0.71o, a secondary lobe level of -35 dB for the azimuth plane and a final gain of 34 dB, greater than that of the original antenna. [ABSTRACT FROM AUTHOR]

Free-spins on slot machines introduce a salient moment of potentially large wins that might influence people to either quit or continue a gambling session. Two theoretical models make different predictions about why people quit a gambling session. From a behaviourist perspective, people quit a session when they are either satiated or the lack of rewards lead to the extinction of behaviour. Alternatively, from a behavioural-finance perspective, people quit due to the disposition effect: a general finding whereby investors tend to sell shares or other assets when the price has increased, but keep assets that have dropped in value. From the behaviourist perspective, we predict that people experience free spins as a moment of intermittent reinforcement, which should encourage them to continue gambling longer. According to the disposition effect, however, the large win would trigger risk-aversion, signalling an opportunity to "cash out" and lock-in the gain. In the present study, 188 gamblers (72 female) were randomly allocated to one of three conditions: control, early free-spins and late free-spins, in an online EGM simulation (points only). Consistent with the disposition effect, participants who received early free-spins quit earlier, placing significantly fewer bets, than those in control condition. The study suggests that free-spins, rather than being reinforcing within session, may signal an opportunity to quit early. In the discussion, however, we speculate on whether future research could demonstrate that a perceived lack of free spins in a session may keep players engaged longer. [ABSTRACT FROM AUTHOR]

The main purpose of this study is to understand and explain the role of the state on the creating, maintaining, and disrupting institutional works regarding slot allocation in the Turkish airline industry field from 1992 to 2010. In the scope of the study, a field-level analysis conducted to determine the institutional works of state and to describe the state as an institutional entrepreneur. Turkish airline industry field examined as a unit of analysis. For this purpose, the study designed as a qualitative case study and research data, including interviews, documents, newspaper articles, and documentaries gathered from multiple sources. The results of the study revealed that as an institutional entrepreneur, the state creates, maintains, and disrupts the institutions with its institutional works. In conclusion, the state is an essential institutional entrepreneur in the Turkish airline industry field. [ABSTRACT FROM AUTHOR]

This paper presents a new design of a compact dual-band Multiple Input Multiple Output (MIMO) antenna with high isolation for WLAN and X-band satellite applications. The proposed antenna is realized using three slots: the first slot is used on the upper layer to create the second resonance frequency at 5.3 GHz and two symmetrical slots are etched on the bottom layer to enhance the impedance bandwidth of the two operating bands. In order to obtain a low mutual coupling, the two antenna elements have an orthogonal polarization. The simulated results show that the MIMO antenna has a high isolation (S21 ≤−22.5 dB) at the two desired bands with impedance bandwidths are about 4.15% (5.19–5.41 GHz) and 4.81% (7.30–7.66 GHz). In addition, the MIMO parameters like envelope correlation coefficient (ECC), diversity gain (DG), Total Active Reflection Coefficient (TARC), realized gain and efficiency are also analyzed. [ABSTRACT FROM AUTHOR]

This paper discusses assembly variation possible when the positioning between two parts is constrained using two cylindrical holes fit over two types of pins. "Positioning" can be realized by means of mating components controlled by the above method. In this paper, one pin is round and the other is diamond-shaped. A case in which a pair of a round pin and round hole, and another case in which a diamond pin and round hole are mating, is studied. In this paper, in order to simplify, the diamond-shaped pin is called a "diamond pin". Two parts positioned using two holes fitting over two pins may move relative to each other during assembly process because of clearances between the pins and the holes. Therefore, assembly variation arises between the two parts. The area in which an arbitrary point can move is called "motion area" in this paper. In order to determine the assembly variation in a precise manner, this paper deals with the motion area that is obtained by positioning using a diamond pin. There are some other positioning methods using two holes to fit over two pins. For instance, (1) two pairs of round pins and round holes, also (2) a pair of a round pin and round hole, and a pair of a round pin and slot. The authors have clarified the motion area using these positioning methods and formulated the maximum motion area. This paper will verify the motion areas by the positioning method using a diamond pin. Then, the results are compared with those of the other positioning methods. Furthermore, the maximum motion area is formulated. [ABSTRACT FROM AUTHOR]

High-speed rotation of the launching components (armature and projectile) is one of the most important ways to improve the firing accuracy of railgun, and the rotation can be obtained by the electromagnetic torques generated by the armature. However, the concrete design or parameter study of the revolving armature-type railgun (RATR) is rarely mentioned. In this article, some key parameters of RATR—interior rail spacing ${d} _{c}$ , outer rail horizontal spacing ${d} _{m}$ and vertical spacing ${d} _{v}$ , armature slot width ${d} _{w}$ , length ${d} _{L}$ , and quantity ${N}$ —are studied. On the basis of the initial structure of RATR, the structural parameters of the RATR are changed respectively. Based on the analysis of armature electromagnetic forces (armature thrust, electromagnetic pressure, and armature torque), the relationship of some key parameters of 15-mm caliber RATR are proposed. Conclusion can be drawn that increasing ${d} _{c}$ can increase the armature electromagnetic forces, but reduce the maximum current that can be transmitted between the armature and the rail. The optimal interval of ${d} _{v}$ is 9 mm $ < {d} _{v} < 13$ mm, where ${d} _{m}$ and ${d} _{v}$ have the greatest influence on the armature torque, so that the armature rotation speed can be controlled by controlling the horizontal and vertical spacing. Armature slot width ${d} _{w}$ has little influence on the electromagnetic forces (< 0.13), but increasing ${d}~_{L}$ can significantly increase the electromagnetic pressure and then increase contact stability. Finally, for the railgun, the optimal number of the slot in the revolving armature is ${N} =6$. [ABSTRACT FROM AUTHOR]

In this article, miniaturization of dual‐band slot antenna design for GPS, WLAN and amateur radio applications is presented. The proposed dual‐band miniaturized antenna is achieved using slits, rectangular split ring and metallic strips fed by 50 Ω microstrip feed. The first resonant frequency is achieved by loading reference antenna with eight slits that is antenna 1 and the second resonant frequency is achieved by loading with one center slits and rectangular split ring that is antenna 2. Dual‐band antenna is achieved by loading reference slot antenna with nine slits and rectangular split ring which resonates at frequency of 1.52 and 3.03 GHz respectively. As a result, it is achieved 53.79% reduction in first band resonant frequency with 76.07% improvement in −10 dB bandwidth and 7.90% reduction in second band resonant frequency compared to reference slot antenna. Further, this dual‐band antenna is miniaturized by metallic strips which are placed on the bottom of the substrate. This results in 61.39% reduction in first band resonant frequency with 32.07% improvement in −10 dB bandwidth and 26.13% reduction in second band resonant frequency in comparison with reference slot antenna topology. [ABSTRACT FROM AUTHOR]

This document presents a dual band dual polarized coplanar waveguide (CPW) antenna with single port feed. Lower resonating band is circular polarized, while the upper band is linear polarized. A novel concept of realizing dual polarization by suppressing the undesired modes is introduced in this work. Orthogonal Even/Odd modes are excited at lower band and a phase difference of 90° is maintained between them. Hence, circular polarization behavior is realized for lower operating band. For upper band, Odd mode is suppressed by introducing step shaped modifications in the ground plane at left side of the feed line, resulting in linear polarized upper band. Dual band nature of the antenna is confirmed by 10 dB impedance bandwidth extending from 3.91‐5.31 GHz to 7.51‐8.72 GHz. Circular polarized nature of lower band is confirmed by enclosure of lower band by 3 dB axial ratio bandwidth extending from 4.01 to 5.59 GHz. Advantages of proposed antenna involves the use of single port feed for generating dual polarization performance along with compact antenna size.(30 × 30 × 1.6 mm3). [ABSTRACT FROM AUTHOR]

This article proposes a design of miniaturized high selectivity band‐pass filter by using a dual‐mode patch resonator with two pairs of uniform slots set in the four corners. The effect of the pairs of the slots on the resonant modes of the square patch resonator is investigated first. For filter design, the slots set in the four corners of the patch resonator are provided as the perturbation elements to tune the resonant modes and thus form the filter response. The pairs of the slots reduce the fundamental resonant frequency and thus miniaturize the filter size. The designed filter is simulated and measured at 1.95 GHz for the fifth generation applications with narrow bandwidth. High band selectivity is obtained due to the creation of transmission zeros near the passband edges. The filter performances are measured by network analyzer and the results are discussed. [ABSTRACT FROM AUTHOR]

A compact planar Ultrawideband (UWB) monopole antenna with quadruple band notch characteristics is proposed. The proposed antenna consists of a notched rectangular radiating patch with a 50 Ω microstrip feed line, and a defected ground plane. The quadruple band notched functions are achieved by utilising two inverted U-shaped slots, a symmetrical split ring resonator pair (SSRRP) and a via hole. The fabricated antenna has a compact size of 24 mm × 30 mm × 1.6 mm with an impedance bandwidth ranging from 2.86 to 12.2 GHz for magnitude of S11 < −10 dB. The four band notched characteristics of proposed antenna are in the WiMAX (worldwide interoperability for microwave access) band (3.25–3.55 GHz), C band (3.7–4.2 GHz), WLAN (wireless local area network) band (5.2–5.9 GHz) and the downlink frequency band of X band (7–7.8 GHz) for satellite communication are obtained. The measured and simulation results of proposed antenna are in good agreement to achieve impedance matching, stable radiation patterns, constant gain and group delay over the operating bandwidth. [ABSTRACT FROM AUTHOR]

The internet of things (IoT) connects billions of smart heterogeneous modules in long‐term evolution (LTE) and LTE‐advance. The rapid growth of IoT has attracted typical wireless sensors designs for machine‐to‐machine communication. More action is required to improve quality, bandwidth, interfacing compatibility and efficiencies of such smart systems. This article presents an antenna design evolution to enhance compatibility, impedance matching and high bandwidth fidelity to smart wireless IoT sensors. A compact 12 × 18 × 1.6 mm3 staircase‐fractal slot antenna with truncated "T" parasites, gives promising characteristics for IoT applications in UWB and GSM/GPS range. Antenna is modeled and simulated on high frequency structure simulator. The prototype is fabricated and experimented to validate practical feasibility of antenna for wireless sensor based applications. The antenna resonates on 2.4, 5, and 9.55 GHz, exhibits complete UWB (3.1‐10.5 GHz). Additionally, offers GPS/GSM compatibility for real time applications. Therefore, the proposed antenna has novel utility of compatibility enhancement among multiple wireless sensors interface embedded in advance IoT based application. [ABSTRACT FROM AUTHOR]

Scouring is one of the major threats to the stability of bridge abutments constructed over rivers. The present study investigated the usefulness of abutment slots in reducing the scour depth around bridge abutments with vertical walls, experimentally. Nine experiments with no slot and hundred experiments with slots were conducted in clear water conditions. Four subcritical flow conditions (Froude number less than 1) were investigated. For each flow condition, 25 different slot models having different sizes, and vertical and horizontal positions were considered. The results indicated that the slots having heights equivalent to half of the flow depth are more effective in reducing scouring if they are located closer to the bed. Increasing the slot height improves the performance. The best performance is achieved when the slot begins from the water surface and extends below the bed (equal to the scour depth in the model without the slot). Further, the results showed that the greater the distance of the slot is from the abutment nose and closer it is to the channel wall, the more effective the slot would be. Therefore, the most effective slot model is the model in which the slot height equals the distance from the water surface to below the bed, and when it is attached to the channel wall. For different slot models, in different flow conditions, the percentage of reduction of scour depth varies from 20 to 100%. [ABSTRACT FROM AUTHOR]

Sports discourse is in focus in linguistics due to the influential power of linguistic means, especially the MetaSelf metaphor. The metaphor is of anthropomorphic character since it assimilates all phenomena to a person, his/her morphology, and behaviour. The article aims to establish metaphorical models of MetaSelf in the English-language sports discourse. 300 metaphors were selected from the US and UK periodicals, and publications on open online sources of the sports press from 2001 to 2019. Analysis of the metaphors on a syntactic level and a semantic level was based on frame semantics and the semantic-cognitive method as tools of an integrative approach. The analysis allowed constructing productive metaphorical models of MetaSelf: the physiological metaphor, social metaphor, and morbial metaphor. Within each model, there were established relevant semantic frames and slots that underlay the majority of the MetaSelf metaphors, with examples included. The findings demonstrated prevalence of the physiological metaphor. In the English-language sports discourse, the MetaSelf metaphor was presented in simple (33.8%) and simple sentences in a compound (25.6%) on a syntactic level, collocations (23.4%) and separate words (17.2%) - on a semantic level. A distribution of various parts of speech illustrated a complex structure of the MetaSelf metaphor in the English-language sports discourse. The MetaSelf metaphor serves as an important linguistic means of pragmatically influencing the sports discourse, in which sport is likened to a person as a living organism. [ABSTRACT FROM AUTHOR]

The aim of the research is to analyze the possibility of the development and realization of a common laser triangulation sensor arrangement-based probe for the measurement of slots and bore sides with the help of a mirror attachment. The analysis shows the feasibility and limits of the solution with respect to the maximum measurement depth and surface distance measurement working range. We propose two possible solutions: one for maximizing the ratio of the measurement depth to the measured bore size and the second for maximizing the total depth, intended for the measurement of slots and large bore sizes. We analyzed measurement error sources. We found that the errors related to the reflection mirror misalignment can be fully compensated. We proved the validity of the proposed solution with the realization of a commercial laser triangulation sensor-based probe and demonstrated a slot side and a bore side surface distance scanning measurement. The probe working range was assessed with regard to the obscuration effect of optical beams.

Full engagement of orthodontic archwires to permit gate closure in self-ligating brackets can be challenging in both the initial stages of alignment with crowded or rotated teeth and also during the later treatment stages with use of heavy rectangular wires. A handy, reliable tool has been developed to ensure complete seating of any archwire in slots of both conventional and self-ligating bracket (SLB) systems to overcome this problem. [ABSTRACT FROM AUTHOR]

Electric motors today have become an important part in technological developments. One type of electric motor that has been and continues to be developed at this time is brushless direct current (BLDC). BLDC is generally applied as an actuator on electric vehicles. The development of electric vehicles make BLDC motor more varied. This research analize the influence of air gap distance on the design performance of BLDC motor with exterior rotor type. The BLDC motor has rated voltage 48 V and input current 23A.

The article presents the results of the frame analysis of the situations of such acts as “help”, “benefaction”, “heroism”, “exploit”, “prank”, “antic”, “trick”, etc. The research is based on the idea according to which the conceptualization of acts is linked with the invariable frame, which is a structure built by the following elements: aim, action, subject, object, valuation, result. The aim of the paper is to show how the names of the acts represent this invariable frame model of an act. In the analysis of the names of acts and their cognate words in speech it was revealed that the elements of the slots are interrelated and characterize different aspects of the situations of acts. The conclusion was made that in different situations various elements of the invariable frame can come into the focus of attention. The research shows that the frame of act is a complex, multidimensional category, which reflects the world and relations between its elements.

A compact phase shifter using substrate integrated waveguide (SIW) with two slots is proposed in this letter. The wideband phase shift is mainly caused by the opposite phase shift slopes produced by the slots and the microstrip delay lines over a wide frequency range. Furthermore, the wide phase shift range (−90° to 90°) can be achieved and be with the same reference line. Compared with the state of the arts, the proposed one gives consideration of the wide bandwidth, wide phase shift range, simple and compact size, and easy-to-make structure, while the SIW counterparts just consider part of the above features. Five prototypes covering the frequency of 26 GHz are designed with the operating bandwidth for 90° ± 5° (−45° ± 2.5°, 45° ± 2.5°, and 90° ± 5°) phase shifter of 26.6% (29.2%, 35.8%, and 39.3%) and the size of $2.29\lambda _{g}^{2}$ ($2.42\lambda _{g}^{2}$ , $2.71\lambda _{g}^{2}$ , and $2.86\lambda _{g}^{2}$ ; $\lambda _{g}$ is the guided wavelength at the center frequency $f_{0}$). [ABSTRACT FROM AUTHOR]

Orthodontic brackets, specifically in their slots, are responsible for receiving active orthodontic forces and transferring them to the teeth to be moved. The presence of an altered slot or inaccurate dimensions can influence the mechanical relationship between the bracket and archwire, interfering with the biomechanics of tooth movement. The objective of this study was by comparing the accuracy of slot placement of upper right lateral incisor metal brackets for Bioprogressive Ricketts therapy from five trademarks. The following characteristics were evaluated: height, torque, and internal parallelism of the walls of the slot. The sample included 75 brackets, 15 each from the following trademarks: 3M Abzil, Forestadent, Morelli Rocky Mountain Orthodontics, and Tecnident. Images of the slot profiles were obtained through standardized techniques using scanning electron microscopy, measured by the AutoCAD 2017 software, and compared to Ricketts prescription, respecting standard deviation with the technical and tolerance parameters present in standard ISO 27020. The results indicated that most of the evaluated characteristics were in accordance with the standard parameters, considering the tolerance adopted. There were exceptions found to this pattern of precision in the 3M Abzil brackets with regard to torque variation, and the Morelli brackets in relation to height variation and parallelism between the walls of the slot. Considering the measured dimensional characteristics, the metal brackets used in Bioprogressive Ricketts therapy has satisfactory pattern accuracy; however, there are still some specific inaccuracies in brackets from certain brands that can require more attention during the detailing phase. [ABSTRACT FROM AUTHOR]

In this letter, a low-profile circularly polarized (CP) narrow-slots slotted-patch antenna for wide 3 dB axial-ratio beamwidth (ARBW) performance is presented. It consists of two pairs of narrow slots along the diagonal lines of a square patch with a single feed. These pairs of narrow slots are conceived and placed to serve as magnetic dipoles with quarter-wavelength separation, forcing the amplitude of the orthogonal electric field components to be equal across a wide angle. The 3 dB ARBW of the CP antenna is a strong function of the mutual magnetic field, which is feasible to alter with different parameters of the slot. The location, dimensions, and gap between the slots are tuned to achieve wide 3 dB ARBW. Measured results of the fabricated prototype exhibit 3 dB ARBW of 226° with ARmin of 0.52 dB and 198° with ARmin of 1.61 dB in two principal planes at $\boldsymbol{\varphi } = \text{0}^\circ $ and $\boldsymbol{\varphi } = \text{90}^\circ $ , respectively. The antenna offers impedance bandwidth of 85 MHz (2.448–2.533 GHz) and CP bandwidth (CPBW) of 23 MHz (2.474–2.497 GHz). The minimum peak gain is 3.87 dBic in the broadside direction. [ABSTRACT FROM AUTHOR]

The microstrip patch antenna is used in various communication applications including cellular phones, satellites, missiles, and radars, due to its several attractive features such as small size and weight, low cost, and easy fabrication. The microstrip patch antenna consists of a top radiating patch, a bottom ground plane, and a dielectric substrate in between. The patch can have different shapes, the rectangular patch being the most commonly used. In practice, the microstrip antenna suffers from narrow bandwidth and low gain efficiency. This paper aims to enhance the bandwidth and efficiency of a rectangular-patch antenna using the High-Frequency Structure Simulator (HFSS). Initially different patch sizes and substrate materials are investigated and optimal antenna parameters are achieved. Then, the antenna performance is further enhanced by inserting single and double slot designs into the patch. Two cost-effective feeding methods are involved in the investigation. The antenna is designed to operate in the Super High Frequency (SHF) band. [ABSTRACT FROM AUTHOR]

Steady air blowing (suction) into a turbulent boundary layer on the NACA 0012 airfoil through singular slots located on the opposite sides near the trailing edge is studied experimentally and numerically. The investigations are performed at the Reynolds number Rec = 0.7 · 106 in the range of the angles of attack α from −6 to 6°; the intensity of the injected and sucked jet characterized by a dimensionless momentum coefficient does not exceed 10−3. It is demonstrated that the result of blowing is not only an increase in the lift force, but also significant enhancement of the drag force of the airfoil. In the case of suction, the increase in the lift force is appreciably smaller despite airfoil drag reduction. [ABSTRACT FROM AUTHOR]

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The design of two novel orientation-independent slot resonator-based chipless RFID tags is proposed in this paper. These tags make use of multiple L-shaped slots of different lengths on a lossy substrate and are appropriate for item tracking and identifications. The data are encoded in the backscattered signal from the tag after its illumination. The first tag configuration includes multiple L-shaped slot resonators cascaded with each other. It exhibits wideband features and enables the addition of extra resonators for encoding of additional data without an increase in the tag size. The second configuration has alternate resonators on one side of the substrate while the remaining resonators are inverted and are on the other half of the substrate. It leads to reduced mutual coupling between the resonators and hence an improved performance and improved printing flexibility. The proof of concept is demonstrated through the design of tags in CST Microwave Studio and prototype development on the Rogers 5880 substrate. Both the tags are compact, printed on 20 mm $\times$ 20 mm substrate, encode 8-bits in a bandwidth of 3 GHz and thus advance the state of the art significantly. An interesting feature of the proposed tags is the orientation independence and this is a very useful feature for applications, such as tracking of items in a smart retail scenario where the products need to be read by the readers from any orientation. [ABSTRACT FROM AUTHOR]

This study analyzes the low-frequency magnetic shielding effectiveness (SE) of a metal plate, in terms of diffusion and slot effects, by conducting a numerical simulation and implementing an analytical solution. When the metal has a low conductivity, the SE is dominated by the diffusion effect. However, when the conductivity and frequency both increase, the slot has a major influence on the SE. These results can be used as guidelines in the shielding design and SE requirements of electromagnetic pulse protection facilities. [ABSTRACT FROM AUTHOR]

This paper examines a disadvantage of low-frequency magnetic shielding measurement based on MIL-STD-188-125-1. A rectangular loop antenna is proposed as an improvement over conventional circular loop antennas for measuring magnetic shielding. Simulation and experiment are used to demonstrate that the proposed rectangular loop outperforms the circular loop for a more reliable shielding measurement at low frequency range. [ABSTRACT FROM AUTHOR]

A gain-enhanced tri-band microstrip antenna using higher order modes was analyzed and designed in this communication. It first proved in theory that by manipulating the equivalent magnetic currents’ (EMCs) relative magnitudes, the higher order modes’ radiation patterns could be converted from conical to broadside. Their zenithal directivities would therefore greatly increase. The relationships between the EMCs’ relative magnitudes and the directivities were studied. Then, those analyses were applied to design a gain-enhanced tri-band microstrip antenna using three higher order modes. A simpler one-port differential feeding and several shorting pins and slots were used to control the antenna’s EMCs to improve its radiation patterns. They could further increase the antenna’s gains and suppress its sidelobe levels and cross-polarizations. The proposed antenna worked at 3.9, 4.95, and 5.9 GHz with consistent broadside radiation patterns and the same polarization. Their measured gains were about 10.0, 10.4, and 10.2 dBi, respectively. [ABSTRACT FROM AUTHOR]

In this paper, a simple and compact rectangular microstrip antenna of H-shape patch has been designed by successively loading rectangular notches of different dimensions and square slots in radiating patch. The conventional microstrip antenna suffers with narrow impedance bandwidth. The current work affords an alternate option to enhance the bandwidth. The bandwidth of recommended microstrip antenna has been obtained 35.61% (<-10dB) and antenna is resonating in single band with two resonant frequencies at 1.729GHz (lower resonant frequency) and 2.223GHz (higher resonant frequency). The recommended antenna has frequency band in the range of 1.639GHz-2.349GHz and it is appropriate for S-band (2-4GHz) and other wireless applications. The return loss of the recommended antenna is -16.97dB at 1.729GHz and -20.14dB at 2.223GHz. The recommended microstrip antenna is directly fed by 50O microstrip line feed. The recommended antenna has been designed, simulated and analyzed by IE3D simulation software. [ABSTRACT FROM AUTHOR]

• The critical level of sediment is detected. • The sediment can be dry, wet or under water level. • The sensing system provides reliable readings. • The sensor can be used in metal or plastic catch basins. This paper presents a low-cost sensor for the early detection of flood in urban catch basins. Blockage and flooding in urban catch basins is caused by accumulation of sediment. This sensor can be installed inside the catch basin for detecting the critical level of sediment. The sensing system is composed of a two-element array of printed circuit board slot lines connected to a data acquisition system via a reading module for real-time monitoring and in-time triggering of the evacuation alarm in a blocked catch basin. The proposed system can reduce the operational costs of water companies by decreasing the incidents of sewer flooding and pollution. [ABSTRACT FROM AUTHOR]

A numerical methodology for three-dimensional fluid dynamics and chemical kinetics simulation of the combustion and gas-exchange processes in the Wankel engine was developed and validated. Two approaches of performance enhancement were studied—the addition of a slot in the rear side of the rotor recess, and installation of a third plug in the trailing side of the working chamber, in addition to the two available plugs mounted in the leading side of the baseline engine. The obtained results showed that the suggested three-plug arrangement significantly improves the engine performance. Furthermore, positioning the trailing plug further from the passage between the trailing and leading sides is of preference for higher mean in-chamber pressures. Nevertheless, for maximum performance, the distance should be brought to an optimum as during the intake stroke there is a loss of inducted charge due to backflow from the trailing plug hole. For the three-plug arrangement the presence of a slot is necessary for the prevention of early flame quenching in the trailing side, while keeping the added volume to a minimum. Moreover, positioning the slot and the trailing plug off-center, results in higher flow intensity towards the leading plugs, and accordingly, to a higher combustion efficiency. For dual-plug ignition system (two plugs in the leading side) it is preferable to maintain minimum clearance in the trailing side.

Circular cylinder flow is controlled using a slot and axially arranged holes (AAH) at a Reynolds number of 32000. When the slot and AAH are placed at small incidence angles from the free-stream direction, the passive jet generated on the leeward cylinder side pushes the wake vortex downstream, reducing the drag compared to the baseline cylinder. If the incidence angle is larger than the critical angle, the alternate blowing and suction induced by the slot and AAH promote a boundary-layer transition on one side and a shear-layer transition on the other. The earlier transition to turbulent flow substantially shortens the separated shear layers on both sides, shifting the wake formation region toward the base and leading to an increase in drag. The AAH has a higher critical incidence angle than the same-size slot, as the passive jet developed from the AAH undergoes a transition to alternate blowing and suction at a higher incidence angle than the slot. Just before the incidence angle of the AAH reaches the critical angle, the weak jet flow induced on the windward cylinder side delays the boundary-layer separation through early separation and laminar reattachment without shortening the separated shear layer, thereby allowing additional drag reduction. • Flow around a cylinder is experimentally controlled using a spanwise slot and axially arranged holes (AAH). • AAH reduces drag over a wider range of incidence angles than the slot of the same size. • Effects of the slot and AAH on the boundary layer, separated shear layer, and near wake are systematically investigated. • Mechanisms for drag variations are explained based on the flow modifications by the slot and AAH. [ABSTRACT FROM AUTHOR]

A novel sextuple band-notched UWB antenna was designed. Sextuple band-notched characteristics could be realized by adding a T-shaped stub, a bent stub, and etching a U-shaped slot on the patch, adding a C-shaped stub, an anti-C shaped stub near microstrip line and etching a pair of L-shaped slots on the ground plane,which effectively sup-presses the interference between narrow band systems and UWB systems. The influence of the proposed structures on band-notched characteristics was studied, and band-notched principle was explained by antenna surface current and equivalent circuit. Finally the antenna was fabricated and measured. The measured results of VSWR, radiation patterns and gains agree well with the simulated results, which demonstrates the correctness of the design method. The proposed antenna has good performance and can be widely used due to its sextuple band-notched characteristics.

Micro-Cantilever (MCL) is a thin film structure that is applied for aerosol particle mass sensing. Several modifications to the rectangular MCL (length-to-width ratio, slots at the anchor, serrations at its side edges) are made to deduce the role and influence of the shape of rectangular MCL-based aerosol mass sensors and reduce gas damping. A finite element fluid-structure interaction model was used to investigate the performance of MCL. It is found that (I) the mass sensitivity and quality factor decline with the increasing of length-to-width ratio which alters the resonant frequency of the MCL. The optimum conditions, including the length-to-width ratio (σlw = 5) and resonant frequency (f0 = 540.7 kHz) of the MCL, are obtained with the constant surface area (S = 45,000 μm2) in the frequency domain ranging from 0 to 600 kHz. (II) The slots can enhance the read-out signal and bring a small Q factor drop. (III) The edge serrations on MCL significantly reduce the gas damping. The results provide a reference for the design of aerosol mass sensor, which makes it possible to develop aerosol mass sensor with high frequency, sensitivity, and quality.