Thermoelectric properties of B-FeSi2 thermoelectric module utilizing cast-iron scrap chips

Semiconducting β-FeSi2 has been considered one of the most promising thermoelectric materials among numerous innovative thermoelectric materials due to its inexpensive cost and exceptional oxidation resistance up to 900 °C. Thermoelectric generation modules consisting of pairs of p-type 0.94C.I.-0.06Co-1.86Si and n-type 0.92C.I.-0.08Mn-1.86Si have been fabricated using Cu sheets as electrodes and Ag paste as bonding material. In an experiment, the maximum power density is measured by using a variable resistor range of 10Ω—10 kohm. Two different temperatures that are tested in this project are 40 and 60 °C. A rectangle and a trapezoid as the thermoelectric leg shape geometry are compared. The percentage difference for voltage is around 21% while the power shows a 41 and 65% difference depending on the temperature difference. The latter percentage difference is possessed by higher T. Based on the comparison with the reference, thermoelectric module from cast iron scrap chips was comparable and better than the reference. Trapezoid shows better geometry than rectangular shape in terms of thermoelectric power density. At 40 °C, the maximum power output are 21.89 and 21.91 μW whilst the maximum power for 60 °C are 28.13 μW and 28.42 μW for rectangle and trapezoid respectively

Capability of AgSiN/SU-8 Layer on Silver-Based SPR for Adulterated Honey Detection

This study introduces the capability of the AgSiN/SU-8 layer on the silver-based SPR structure for water content detection in stingless bee honey. The 30% water content in pure honey was adulterated by water bath procedure until they reached 18% adulterated honey. The experiment was carried out for two different SPR structures, with and without AgSiN/SU-8 layer to examine its potential in protecting the silver metal from eroding and minimize the formation of the silver oxide. The resonance angles of adulterated honey solutions for these two SPR structures denote a similar behavior by shifting to a higher angle from the pure honey solution. It indicates that the AgSiN/SU-8 layer can select and detect the variation percentage of honey water content. After 24 hours, the Cr/Ag/AgSiN/SU-8 structure produces the equivalent resonance angle value with only 5.26% changes in minimum reflectivity. It shows that the AgSiN/SU-8 layer can protect the silver surface from erosion and preserve the SPR characteristic. Besides, the presence of the AgSiN/SU-8 layer on the silver surface is capable of decreasing the oxygen atomic percentage by 21.48%, hence minimizing the growth of silver oxide. This work is a preliminary study of the AgSiN/SU-8 layer to detect water content in stingless bee honey, at the same time can protect the silver surface from erosion and minimize the formation of the silver oxide

Generation of Kelly and dip type sidebands soliton employing Topological insulator (Bi2Te3) as saturable absorber

Conventional Kelly sidebands soliton and dip-type sidebands soliton were observed with the employment of Bi2Te3 as saturable absorber (SA) in Erbium-Doped Fiber Laser (EDFL). The fabricated Bi2Te3 possessed the following characteristics: Isat 102 MW/cm2, modulation depth 41.4%, and non-saturable absorption at 10%. The Bi2Te3 solution was transferred to the end of the fiber ferrule by the optical deposition method. Conventional Kelly sidebands soliton was obtained with a fundamental repetition rate and pulse width of 24 MHz and 0.78 ps, respectively. The existing cavity length was extended and with the appropriate tuning of light polarization, dip-peak intensity soliton sidebands with bunched pulses were observed. The oscillation trace revealed the repetition rate of dip-peak intensity sidebands soliton was ascertained at 13.5 MHz, which was in accordance with the cavity length. There was a total of 144 pulses in a single bunch envelope under the maximum available pump power. With the appropriate tuning of light polarization, constructive and destructive interference between soliton and dispersive waves took place in EDFL resulting in the formation of peak intensity (Kelly sidebands) and dip-peak intensity on the soliton spectrum. To the best of the author’s knowledge, this is the first demonstration of dip-peak intensity sidebands soliton using Bi2Te3

Optoelectronic properties comparison of 10 and 20 multi quantum wells Ga0.952In0.048N0.016As0.984/GaAs p-i-n photodetector for 1.0 µm wavelength

This study proves the addition of quantum wells to the intrinsic regions of p-i-n GaInNAs/GaAs has improved the performance of optoelectronic devices. The optoelectronic properties that contribute to the device's dark current and photocurrent need to be well understood to develop photo-response at longer wavelengths. This study reports an optoelectronic properties comparison of different quantum well number for Ga0.952In0.048N0.016As0.984/GaAs-based dilute nitride multi-quantum wells (MQWs) p-i-n photodetector devices. From photoluminescence (PL) analysis, 20 MQWs shows a higher PL peak than 10 MQWs. The maximum quantum efficiency (QE) is found to be 80.3% for 20 MQWs and 46% for 10 MQWs, where 20 MQWs being the highest QE value ever reported for GaInNAs-based MQWs photodetector. Current versus voltage (I–V) measurement shows that 20 MQWs produces lower dark current than 10 MQWs. Besides, 20 QWs sample produces a higher current density (−12.43 μAcm−2) than 10 MQWs (−7.52 μAcm−2) under illumination. Impedance spectroscopy analysis shows that a lower dark current of 20 MQWs is due to a high intrinsic resistivity and low dielectric loss peak compared to 10 MQWs. SimWindows simulation shows good correlation with responsivity analysis and impedance analysis where at −5 V, 20 MQWs produces higher responsivity (0.65AW-1) due to wider depletion region (deduce from conduction band profile) and lower intrinsic capacitance and dielectric loss (deduces from impedance analysis) than 10 MQWs (0.37AW-1). At room temperature, the detectivity (D*) of the 20 MQWs photodetector (7.12 × 1010 cmHz0.5W−1) is higher than 10 MQWS photodetector (4.89 × 1010 cmHz0.5W−1). Finally, the 20 MQWs's (4.02 × 10−11 WHz−0.5) has produces lower noise-equivalent power (NEP) than 10 MQWs (5.85 × 10−11 WHz−0.5). This study has successfully presenting an understanding of optoelectronic properties and simultaneously producing a sensitive photodetector with high quality, low-noise which is comparable with ∼1010 cmHz0.5W−1 of commercial III-V alloy based near-infrared GaAs-based photodetectors

Development of a flexible rogowski coil sensor for partial discharge detection in power cables

Partial discharge (PD) is a prevalent problem in power cables that must be detected early to avert power outages and ensure system reliability. Despite the fact that numerous Rogowski coil (RC) designs, none of them can accommodate all cable sizes. The purpose of this research is to investigate the sensitivity of flexible RC sensors and develop a prototype that uses Thermoplastic Polyurethane (TPU) for enhanced flexibility and accuracy. This study emphasizes the significance of flexible RC sensors in early PD detection for enhanced flexibility and potential benefits for power system monitoring and maintenance. The RC construction is designed in AutoCAD and 3D printed in TPU. The RC is wound with 20 turns and employs a return loop method to reduce interference from external electromagnetic fields. According to experimental validation, the sensor sensitivity is directly proportional to the greatest amplitude of the recorded PD signal, demonstrating the potential to improve power system dependability and safety through early PD detection. These findings highlight the need to consider the PD signal's maximum amplitude for sensor sensitivity, ultimately adding to the power system's reliability and safety. The proposed design, characterized by its novelty with TPU materials, yields promising results in terms of flexibility, establishing flexible RC sensors as a feasible asset in power cable PD detection and boosting monitoring and maintenance practice

Fault localization on power cables using time delay estimation of partial discharge signals

Precise localization of partial discharge (PD) sources on power cables is vital to prevent power line failures that can lead to significant economic losses for electrical suppliers. This study proposes four methods to estimate the time delay of PD signals under electromagnetic interference, including white Gaussian noise (WGN) and discrete sinusoidal interference (DSI), using denoised PD signals with signal-to-noise ratios ranging from 10.6 to -7.02 dB. The maximum peak detection (MPD) and cross-correlation (CC) approaches, as well as two new techniques, interpolation cross-correlation (ICC) and envelope cross-correlation (ECC), are evaluated for their effectiveness in PD source localization. The researchers employ the time difference of arrival (TDoA) algorithm to compute PD location using the double-end PD location algorithm, where the PD location precision serves as an indicator of the accuracy of the time delay estimation methods. The study concludes that CC and ICC are the most suitable methods for estimating the time delay of PD signals in the PD location algorithm, as they exhibit the lowest error rates. These results suggest that CC and ICC can be used effectively for precise PD source localization under electromagnetic interference on power cables

Performance evaluation of Ag doped TiO2 nanoflowers in Dye-sensitized solar cell

Many attempts have been made over the last few years to create effective visible light-activated photovoltaic using Titanium dioxide as photoanode materials in Dye-sensitized solar cell (DSSC). TiO2 possesses high photocatalytic behavior but has high charge recombination. In this study, the effect of introducing Ag dopant in TiO2 nanoflower morphology as a blocking layer to reduce charge recombination is investigated. The fabricated Ag doped TiO2 nanoflower was characterized using XRD, UV-Vis, IPCE, EIS analyses and Solar simulator under 1M solar illumination. Ag dopant may be considered a great approach to improving electron harvesting by suppressing electron recombination between the interface of TiO2 and electrolyte

Impedance spectroscopy analysis of Al/100-plane AlN/p-Si MIS prepared by HiPIMS method for tailoring dielectric properties

The effects of variation of sputtering pressure of AlN HiPIMS deposition on Si substrate to the structure and electrical properties were investigated through XRD, AFM and impedance spectroscopy method. The strong preferred 100-plane AlN was observed for all samples from XRD pattern. The AlN thin film thickness was observed decrease with the increase of sputtering pressure. AFM analysis shows the lowest surface roughness at 0.84 nm for 5 mTorr sputtering pressure. Impedance spectroscopy analysis of Al/100-plane AlN/Si MIS structure shows the electrical conductivity of AlN was directly proportional to the sputtering pressure and stable with temperature ranging from room temperature (299 K) to 353 K. Good dielectric stability was achieved at 3 mTorr sputtering pressure for all variation temperature and the dielectric constant calculated at average 3.5

Towards enhancing power system protection in distribution systems with distributed generation: a graph theory-based systematic relay placement approach

This manuscript presents an innovative approach to optimize power system protection through strategic relay placement in distribution systems with distributed generation (DG). Traditionally, distribution systems relied on radial configurations, assuming power flow from the grid feeder to downstream networks. However, with the integration of DG technologies, the complexity of relay placement and maintenance increases. The study aims to address protection system issues associated with connecting DGs, such as tripping of production units, blinding of protection, and undesirable islanding. The proposed methodology combines graph theory, energy not supplied (ENS) values, and relay coordination strategies to achieve reliable power system operation. The algorithm is implemented in MATLAB, utilizing data from Dig Silent power Factory. The key constraints for relay placement, including islanding operation, relay coordination, and load priorities, are considered to minimize the number of power outages and increase overall system reliability. The effectiveness of the algorithm is demonstrated using IEEE 33-bus and 69-bus test systems under different conditions. Results show consistent and reliable relay placement locations, considering DG locations and load priorities. The algorithm's speed, effectiveness, and adaptability to different network topologies make it a promising approach for power system protection planning in distribution systems with distributed generation

Dissipative soliton generation with sidebands using Bismuth Telluride (Bi2Te3) in erbium doped fiber laser

In this work, the demonstration of dissipative soliton (DS) was observed in erbium doped fiber laser (EDFL) using of Bismuth Telluride (Bi2Te3) nanosheets saturable absorber (SA). The prepared SA was deposited on a fiber ferrule using optical deposition method. Interestingly, the DS generatered was accompanied with sidebands and the number of sidebands grew with laser diode pump power. Sidebands were observed as a result of modulation instability (MI) process, which arises from the interaction between DS and nonlinear gain in the fiber laser cavity. Signal to noise ratio (SNR) of 58 dB was attained, confirming the stability of the generated pulse. This work proved the capability of Bi2Te3 as SA for generating DS with sidebands in an EDFL