Schools were expected to form a physics learning process that builds a scientific foundation through technological engagement. The involvement of traditional technology in physics learning ...potentially contributes to the preservation of local wisdom. Model of learning that concretely integrates harmoniously the involvement of traditional and modern technologies was still needed. In this research, the advance organizer model was combined with the concept attainment model to improve the students' conceptual understanding and cultural knowledge in SMAN 7 Pontianak using non-equivalent control group design on the sound wave subject matter. The syntax of the applied model consists of five phases, namely: Presentation of the advance organizer; Presentation of learning material structure; Presentation of data, identification, and strengthening of the cognitive organization; Testing the achievement of the concept; and Analysis of thinking strategy. The whole phase involves smartphone technology with Dongle or Anycast mirroring combined with PowerPoint and spectrum analyzer in Spectroid applications based on Android. Traditional technologies presented in the learning including Sape', Senggayung, Ntunikng, Tentawaq, Kangkuang, Tuma, Meriam Karbit, and Keledi. The result of n-gain calculation shows that learning using Traditional-Technology Resystemmed and Aligned on Concept Exploration with Smartphone Sensor Model could improve the students' conceptual understanding and cultural knowledge better.
Beginning on 2020 June 19, at a heliocentric distance of 124.2 au, the Voyager 2 Plasma Wave Science instrument began to observe radio emissions followed by electron plasma oscillations in its 3.11 ...kHz spectrum analyzer channel. Plasma oscillations at this frequency imply an electron density in the range of 0.12 cm−3 15%, although some response in the 1.78 kHz channel near the peak of the plasma oscillations suggest a density of 0.087 cm−3 8%. Shortly after Voyager 2 crossed the heliopause, in late 2019 January, the Voyager 2 Plasma Wave Science instrument detected plasma oscillations in its 1.78 kHz channel giving an electron density of 0.039 cm−3 15%. While the Voyager spectrum analyzer affords relatively poor spectral resolution, the recent observation of plasma oscillations in the 3.11 kHz channel provides definitive evidence of a radial density gradient in the very local interstellar medium (VLISM), just beyond the heliopause with a magnitude similar to that observed by Voyager 1 obtained with higher spectral resolution measurements. Plasma oscillations observed by Voyager 1 range from frequencies as low as 2.1 kHz increasing to about 3.2 kHz, giving an electron density profile that increases from about 0.055 to about 0.13 cm−3 over a distance spanning some 20 au. Given the 67° difference in heliographic latitude and 43° difference in longitude between the two Voyagers, the new Voyager 2 observations imply that the density gradient is a large-scale feature of the VLISM in the general direction of the heliospheric nose.
In this paper, the free radical polymerization method was used to design different molecular structures of polycarboxylate slump-preserving agents. The effects of different functional monomers, ...acid-to-ether ratio, ester density, side chain length, and other factors on the dispersion and slump-retaining properties of concrete under high temperatures were compared and analyzed. The optimal process of high-temperature resistance was screened, before and after the alkali hydrolysis treatment, and the dispersing and retention performance of the slump-retaining agent was tested. The high-temperature slump-preserving agent was verified by gel chromatography and an infrared spectrum analyzer, which provided technical support for solving the rapid collapse of concrete in a high-temperature environment in summer.
Objective: The purpose of this contribution is to estimate the path loss of capacitive human body communication (HBC) systems under practical conditions. Methods: Most prior work utilizes large ...grounded instruments to perform path loss measurements, resulting in overly optimistic path loss estimates for wearable HBC devices. In this paper, small battery-powered transmitter and receiver devices are implemented to measure path loss under realistic assumptions. A hybrid electrostatic finite element method simulation model is presented that validates measurements and enables rapid and accurate characterization of future capacitive HBC systems. Results: Measurements from form-factor-accurate prototypes reveal path loss results between 31.7 and 42.2 dB from 20 to 150 MHz. Simulation results matched measurements within 2.5 dB. Comeasurements using large grounded benchtop vector network analyzer (VNA) and large battery-powered spectrum analyzer (SA) underestimate path loss by up to 33.6 and 8.2 dB, respectively. Measurements utilizing a VNA with baluns, or large battery-powered SAs with baluns still underestimate path loss by up to 24.3 and 6.7 dB, respectively. Conclusion: Measurements of path loss in capacitive HBC systems strongly depend on instrumentation configurations. It is thus imperative to simulate or measure path loss in capacitive HBC systems utilizing realistic geometries and grounding configurations. Significance: HBC has a great potential for many emerging wearable devices and applications; accurate path loss estimation will improve system-level design leading to viable products.
Abstract
This paper presents the most recent mathematical modelling and procedure for Laser-Doppler Anemometers (LDA) calibration used by the Brazilian National Institute of Metrology Institute, the ...National Institute of Metrology, Quality and Technology (Inmetro). Here we calculate the fringe spacing calibration coefficient (C
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) and the Burst Spectrum Analyser (BSA) calibration coefficient (C
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). Using these two calibration coefficients we can calibrate a LDA in a determinate velocity range.
Abstract
The number of software in the telecommunications world allows us to make an FM simulation, one of the software is GNU Radio. This paper will explain FM communication simulations that use a ...guide between GNU Radio and RTL-SDR and are validated using a spectrum analyzer. The simulation is carried out twice, the first simulation tests the SDR transmit which will be tested in the simulation to be carried out in the GNU Radio worksheet. The second simulation tests an SDR receiver that uses a frequency of 100.3 MHz. Validation is done at a distance of ± 1 meter using a spectrum analyzer connected to the antenna and will receive frequencies of 60,65,70,75 and 80 MHz which will be compared with GNU Radio readings. The parameters to be used are signal to noise ratio (SNR) and beam power. From the results of the first simulation study using GNU Radio worksheets obtained the value of the emission power of -12.4 dBm and the second simulation obtained a value of -12.87. While the validation results show that the value obtained is the accuracy of 99.5% on the measurement of the transmitter’s power value while the signal to noise ratio of 99.78%.
Here, we propose an all-fiber actively mode-locked Bismuth (Bi)-doped fiber laser based on the use of an acousto-optic modulator. The mode-locked Bi-doped fiber laser produces 13ns pulses with a ...repetition rate of 1.683MHz at 1340nm. Higher harmonic mode-locking is achieved simply by changing the operating frequency of the acousto-optic modulator. The output power of the laser is 7mW and this is further amplified to 101mW using an external Bi-doped fiber amplifier. A peak power of 4.6W with a pulse energy of 60nJ is achieved after the master oscillator power amplifier. The stability of the laser is studied using an RF spectrum analyzer and an SNR of more than 60dB at the fundamental frequency of 1.683MHz was recorded. Furthermore, wavelength tuning of the Bi-doped fiber laser is explored and demonstrated from 1300 to 1370nm.
Supported by advanced digital signal processing algorithms and application specific integrated circuits, coherent receivers in elastic optical networks will be capable of measuring link impairments ...in real time. Specifically, coherent receivers can work as soft optical performance monitors. Optical spectra usually contain rich information about optical links and have been exploited to assist soft failure detection and identification. However, acquiring optical spectra needs the deployment of numerous optical spectrum analyzers. Instead, the digital spectra of received signals in coherent receivers are easy to obtain without the penalty of additional hardware. In this paper, we explore the feasibility of the digital spectra in assisting soft-failure detection (SFD) and soft failure identification (SFI). A digital spectrum based SFD and SFI framework is proposed. A dual-stage SFD structure is employed to reduce the monitoring and processing overhead in optical nodes. At the first-stage SFD, only bit error rate and received optical power are collected. When an anomalous sample is detected, extra digital spectrum features are extracted and collected for the second-stage SFD. Extensive numerical results are presented to analyze the digital spectrum characteristics and feature distributions of four common soft failures. Finally, we experimentally evaluate the detection and identification performance of the proposed method. With reasonable complexity, a false positive rate of 0.42% and a false negative rate of 1.47% can be achieved for SFD, and an identification accuracy of 99.55% can be obtained for SFI.
An experimental approach to estimate cross-eye gain for a nonretrodirective cross-eye jamming (NRCJ) system is presented. Cross-eye gain is used as an index to evaluate the cross-eye jamming system. ...The previous experimental method for obtaining the cross-eye gain using a network analyzer is accurate but requires a complex configuration. In this letter, a method of estimating the cross-eye gain for the NRCJ system by the signal power difference using a spectrum analyzer is proposed. To verify the proposed method, a prototype of the NRCJ system was fabricated. The experimental results showed that the proposed method could estimate the cross-eye gain with a phase-difference error of approximately 2° compared to the simulation.
BepiColombo Mio (previously called MMO: Mercury Magnetospheric Orbiter) was successfully launched by Ariane 5 from Kourou, French Guiana on October 20, 2018. The Mercury Plasma/Particle Experiment ...(MPPE) is a comprehensive instrument package onboard Mio spacecraft used for plasma, high-energy particle and energetic neutral atom measurements. It consists of seven sensors including two Mercury Electron Analyzers (MEA1 and MEA2), Mercury Ion Analyzer (MIA), Mass Spectrum Analyzer (MSA), High Energy Particle instrument for electron (HEP-ele), High Energy Particle instrument for ion (HEP-ion), and Energetic Neutrals Analyzer (ENA). Significant efforts were made pre-flight to calibrate all of the MPPE sensors at the appropriate facilities on the ground. High voltage commissioning of MPPE analyzers was successfully performed between June and August 2019 and in February 2020 following the completion of the low voltage commissioning in November 2018. Although all of the MPPE analyzers are now ready to begin observation, the full service performance has been delayed until Mio’s arrival at Mercury. Most of the fields of view (FOVs) of the MPPE analyzers are blocked by the thermal shield surrounding the Mio spacecraft during the cruising phase. Together with other instruments on Mio including Magnetic Field Investigation (MGF) and Plasma Wave Investigation (PWI) that measure plasma field parameters, MPPE will contribute to the comprehensive understanding of the plasma environment around Mercury when BepiColombo/Mio begins observation after arriving at the planet Mercury in December 2025.
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