935 research outputs found

    Developed high gain microstrip antenna like microphone structure for 5G application

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    We present a new development of microstrip antenna structure combining a simple circular structure with a ring antenna structure as the parasitic element to improve the antenna gain and bandwidth for 5G mobile application. The proposed antenna was fed by a 50Ω microstrip feeding line due to its advantages in performance. The antenna was designed and simulated using a single substrate with double layered copper (top and bottom) with the radiating patch on the top layer and full ground on the bottom layer of the same substrate. Three antennas have been designed namely; design1, design2 and design3 to complete the research works.The antennas ware simulated and optimized at 18 GHz using Computer Simulation Technology (CST) with permittivity, r = 2.2 and thickness, h = 1.57mm on low-loss material Roger RT-Duroid 5880 substrate. The antennas ware reasonably well matched at their corresponding frequency of operations. The simulation and measurement results have shown that the antenna works well. The simulation results have shown that the three antennas works well at the selected frequency. The final simulated antenna for design1, design2 and design3 has been fabricated to measure the performance and also to validate the simulation result with the measurement result. The measurement data for antenna design1, design2 and design3 shows frequency shift of 3% from the simulation result. The final protype of design3 gives 6.6dB gain, -14.51dB return loss, 180MHz bandwidth, and antenna efficiency of 53.9%. All three antennas ware measured using Vector network analyzer (VNA) and Anechoic chamber

    Feasibility of LoRa Implementation for Remote Weather Monitoring System through Field Measurement and Case Study Analysis

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    This paper discusses the feasibility of Long Range Wide-area network (LoRa-WAN) implementation for weather data collection and transmission in remote locations, specifically in east Malaysia. Currently, Malaysia Meteorological Department (MetMalaysia) has installed more than 100 weather stations around Malaysia, and out of this number, there are many stations, mostly in east Malaysia that are dependent on Very Small Aperture Terminal (VSAT) services for data transmission due to unavailability of mobile coverage. Due to significant cost of VSAT subscription, LoRa communication is proposed as an alternative solution due to its low power, low-cost, and long range characteristics. In this paper, the study has been performed through two stages; first, technical performance of LoRa network was validated through field measurement in urban areas to determine the actual LoRa characteristics in real condition. In the measurement, a LoRa module operating at 433 MHz was used to demonstrate a single channel LoRa gateway that acted as a bridge to communicate between LoRa node to IP network. Parameters such as received power spectrum and free space path loss were recorded for analysis. Second, based on the measured data, extrapolation of maximum feasible distance of LoRa signal propagation was done to analyze the viability of implementing LoRa in various locations of existing weather stations in Sabah and Sarawak. Two case studies are presented in this paper, with the aim to evaluate the suitable location of LoRa gateway to establish communication with the existing weather stations when LoRa network is used. Detailed link budget analysis was performed for each scenario. Based on the comparison between theoretical and measurement, the power transmitted from LoRa node shows inconsistent readings throughout the day, suspected due to the changes in spread factor that has been automatically set by the module. Nevertheless, taking into account this factor, it was found that the transmission range was adequate for some remote locations. Meanwhile, for some locations that are separated too far from each other, higher power is needed to allow consistent communication

    Air Pollutant Index Calendar-Based Graphics for Visualizing Trends Profiling and Analysis

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    Detection of air quality abnormality is important as an early warning system for air quality control and management. The information can raise citizens’ awareness towards current air quality status. By using time series plot, the data pattern can be identified but not able to exactly determine the abnormality due to overcrowded plot. Therefore, visualization data profiling was presented in this study by using seven years Malaysia daily air pollutant index to improve the detection. Result shown, the developed approach can simply identify the poor air quality across the month and year. Malaysia air quality was good and consistent between November and May. However, upward trend existed between June and October due to the forest fire happened in Sumatra. This visualization approach improved air pollution detection profiling and it is useful for related agencies to guide the control actions to be taken. This approach can be applied to any countries and data set to give more competent information

    Analgesic efficacy and safety of peri-operative pregabalin following radical cystectomy: A dose grading study

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    AbstractPurposeAdding novel drugs like pregabalin to analgesic regimens might reduce postoperative pain, total opioid consumption and side effects, this study compares multiple doses of pregabalin for postoperative analgesia following radical cystectomy.MethodsThis study is registered at www.clinicaltrials.gov at no.: NCT02724293. Sixty patients were randomized into 4 groups: Group I: control (placebo) group, Group II: received pregabalin 300mg 2h preoperatively, Group III: received pregabalin 300mg 2h preoperatively and 12h thereafter, Group IV: received pregabalin 600mg 2h preoperatively. Postoperative pain, time to first request of analgesia, and total morphine consumption were recorded.ResultsVAS was significantly reduced in groups II, III, IV in comparison with group I immediately postoperative, and after 2h (P<0.05). Sedation score was significantly higher in groups II, III, IV compared to group I immediately postoperative (P<0.05). First request of analgesia was significantly delayed in groups II, III, IV compared to control group (P=0.000). Total analgesic consumption was significantly reduced in groups II, III, IV compared to group I (P=0.000). Group IV showed a significantly higher incidence of dizziness compared to group I.ConclusionPeri-operative pregabalin at doses of 300mg and 600mg reduced postoperative opioid consumption and prolonged time to first request of analgesia in patients who underwent radical cystectomy, and a single preoperative dose of 600mg is superior in analgesia to others, without serious side effects

    Effect of Triple Treatment on the Surface Structure and Hardness of 304 Austenitic Stainless Steel

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    Nitriding, annealing, and carbonitriding processes are conducted to modify the surface of AISI 304 austenitic stainless steel via radio frequency plasma. A ~20 μm thick nitride layer is obtained in ten minutes at a plasma power of 450 W. Hence, all nitrided samples are annealed under vacuum for one hour at 400 ̊C. The nitrided-annealed samples are carbonitrided via the identical technique at various C2H2/N2 gas pressure ratios. Numerous analytical techniques, including X-ray diffractometry, glow discharge optical spectroscopy (GDOS), Talysurf Intra Profilemeter, optical microscopy (OM), scanning electron microscopy (SEM), and Vickers microhardness tester, were employed to investigate the triple-treated specimens. Microstructure analysis of the triple-treated samples reveals the formation of N2 expanded austenite phase (γN), γʹ-Fe4N, CrN, Fe3C, and Fe7C3. The results indicate that the elemental composition, microhardness, and thickness of the triple-treated layers are all depending on the gas composition. After carbonitriding, the total thickness of the compound layer grew from ~20 to ~34.5 μm. The surface microhardness of the triple-treated samples increased as the C2H2/N2 gas composition ratio increased up to 70%, reaching 1,497±33.5 HV0.1, which is ~6.8 and ~1.42 folds higher than the untreated and prenitrided samples, respectively

    Design of Serial-Fed Bend-Array and Measured Results

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    For the next generation mobile system (5G), a cylindrical lens antenna is developed for mobile base station application. As for the feed radiator for this lens antenna, bendarray configuration that produces a bifurcated beam is also developed. The bend-array configuration consisting of four rectangular patch array elements with serial feed network. In previous work, achievement of the bifurcated beam by bendarray configuration was shown by electromagnetic simulations. In this paper, a practical bend-array composed of four numbers of patch elements is fabricated. To verify the radiation characteristics, measured results of antenna input characteristic and radiation pattern are compared with the designed results. Through good agreement of measured and designed results, achievement of practical antenna is ensured

    Investigation of Potential Grounding Compound for Portable Applications

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    This paper applies to the electrical engineering world by making earthing system portable in providing low and acceptable resistance path. The system is develop in a small scale portable earthing system against the massiveness of Earth and becomes leverage if soil at the place is not suitable for plant grounding system. Hence, this paper presents findings on the research of new grounding medium material that will be housed in a small scale enclosure which behaves like native earth related earthing system by using kaolin and bauxite. The data obtained from lightning flashover testing, morphological and chemical composition of material analysis indicated that bauxite is more useful for portable grounding system application much better than kaolin in term of zero reference point function. The portable earthing system can be apply to air aviation systems , railway systems and military sectors particularly for electronic equipment zero referencing

    Shallow subsurface structures and geotechnical characteristics of Tal El-Amarna area, middle Egypt

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    Abstract The shallow seismic refraction profiling was carried out at 18 sites in Tal El-Amarna, which is a flat area on the eastern bank of the Nile River, 50 km south of El Minia Governorate, middle Egypt. The collected data are used to estimate the P-wave velocity and to delineate the near-surface ground model beneath the study area. This study is supported by the National Research Institute of Astronomy and Geophysics due to the historical interest of the Tal El-Amarna area as a famous tourist place where there exist many Pharaoh temples and tombs. This area is low seismically active, but it is probably of high vulnerability due to the influence of the local geological conditions on earthquake ground motion, as well as the presence of poor constructions in the absence of various issues such as building designs, quality of building materials, etc. Another dataset at the study area is obtained by multi-channel passive source (microtremor) measurements, which have been recorded at four arrays. The frequency–wavenumber (f–k) method was used to derive the dispersion curves from the raw signals at each array. The resulted dispersion curves were inverted using the neighborhood algorithm to obtain the shear and P-wave velocity models. The concluded Vs and Vp values provide a preliminary estimation of the geotechnical parameters and site classification for the shallow soil as they are of great interest in civil engineering applications

    Mycobacterial CYP121 as a target for anti-TB drug discovery

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    Despite the introduction of the first line treatment regimen forty years ago and the continuous trials since that time to introduce new regimens, tuberculosis (TB) is considered to be the cause of considerable mortality worldwide. Recent research highlighted the Mycobacterium tuberculosis (Mtb)CYP450s as potential drug targets. This article reviews mycobacterial CYP121 as a target for anti-TB drug discovery
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