The baseline signal in structural inspection based on guided waves is difficult to be obtained under varying environmental conditions. To guarantee the precision of damage identification, developing ...baseline-free damage detection methods is significant in practical structural monitoring work. Conventional instantaneous baseline measurement needs a large number of PZT transducers. In this paper, a novel damage identification method for plate-like structures based on distance compensation is proposed to overcome this shortage. Combining with the concept of instantaneous baseline measurement, pitch-catch pairs of different propagation distance can be compared together to reveal the health information of the measured paths. This method overcomes the drawback of instantaneous measurement, which can only monitor the paths of identical wave travelling distance. Both simulations and experiments are conducted to validate the proposed method. Using this method, the influence of damage size and classification on amplitude variation is discussed. Finally, a baseline-free damage imaging technique is developed based on amplitude loss ratio of the first arriving wave package. The result shows a good agreement of the predicted result and the real damage location.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
An electrical islanding detection method for DC microgrid (MG) is proposed in this paper. Unlikely conventional AC MG system protection has been challenging for the DC MG system. The goal of the ...proposed scheme is to detect the islanding intelligently within the agent nodes. The proposed islanding detection technique detects the electrical link failure intelligently, and if any electrical link failure occurs, then the proposed technique maintains the MG operation and load sharing. Islanding detection is carried out using an injection signal and utilizes the existing communication network to check network connectivity. After checking the network connectivity, all the nodes maintain the look-up table of the connected network. This research work illustrates that the proposed electrical islanding detection technique is effective in maintaining the DC MG operation in the case of an electrical islanding/link failure scenario. The proposed scheme’s performance is checked through MATLAB/Simulink for the detection of islanding and maintaining the operation.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This study focuses on the synthesis and application of Co
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O
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nanorods in post plasma catalysis (PPC) for toluene degradation. Results show that the addition of catalyst significantly improves the ...efficiency of the PPC system. Using non-thermal plasma (NTP) alone,
O
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was produced and successfully used to completely oxidize toluene. Moreover, the system exhibits higher carbon dioxide selectivity and significantly reduces the production of VOCs and NOx. The nanorod structure of the catalyst plays a critical role in its remarkable performance due to the high surface area and more catalytic sites for reaction. Analysis of toluene degradation at various input powers showed complete oxidation at 40 W. These results indicate that the combination of cobalt oxide nanorods and NTP post plasma catalysis is a practical approach to lowering toluene and other unwanted secondary pollutants. Overall, this study demonstrates the potential of Co
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O
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nanorods as an effective catalyst for PPC systems in the treatment of volatile organic compounds.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this research work, hollow structured Co
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nanospheres were prepared and applied in post plasma catalysis. The employed catalyst increased its potential to degrade the toluene efficiently. The ...study verified complete oxidation of toluene upon efficiently using O
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produced during the process. It also shows higher carbon dioxide selectivity, no risk of other VOCs’ production and significant reduction in NOx production. The excellent performance resulted due to the peculiar structure of employed catalyst providing high surface area with greater number of catalytic sites. Furthermore, toluene degradation at different input powers was analyzed and found its complete removal at 40 W. All results obtained during the study indicate coupling of NTP with Co
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hollow nanospheres as the most viable approach for the control of toluene and other secondary byproducts.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The aim of the current research was to develop and present an effective methodology for simulating and analyzingthe electrical and structural properties of piezoelectric material. The finite element ...method has been used to makeprecise numerical models when dielectric, piezoelectric and mechanical properties are known. The static anddynamic responses of circular ring-shaped barium titanate piezoelectric material have been investigated using thecommercially available finite element software ABAQUS/CAE. To gain insight into the crystal morphology and toevaluate the purity of the material, a microscopic study was conducted using a scanning electron microscope andenergy dispersive x-ray analysis. It is found that the maximum electrical potential of 6.43 V is obtained at a resonancefrequency of 35 Hz by increasing the vibrating load. The results were then compared with the experimentally predicteddata and the results agreed with each other. KCI Citation Count: 2
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Five natural dyes were extracted from the peels of Malus domestica, Punica granatum, Phoenix dactylifera, Raphanus sativus and Solanum melongena by maceration in methanol for application in ...dye-sensitized solar cells. Their photophysical, electrochemical and photovoltaic properties were investigated. Thin layers of nano materials ZnO and TiO2 were deposited on FTO glasses by doctor’s blade technique. These films were dipped in the dye solution bath for twenty-four hours. The results verified that Solanum melongena dye has better efficiency 1.10% as compared to other dyes. We also investigated that TiO2 is a better photoelectrode as compared to ZnO. By using Solanum melongena andTiO2 nanoparticles we found 1.10% efficiency and 0.67% by using ZnO as photoelectrode. The results indicate that TiO2 is a better photoelectrode as compare to ZnO. Lower efficiency of the natural dyes as compared to synthetic dyes may be due to lower active contents for DSSCs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The aim of the current research was to develop and present an effective methodology for simulating and analyzing the electrical and structural properties of piezoelectric material. The finite element ...method has been used to make precise numerical models when dielectric, piezoelectric and mechanical properties are known. The static and dynamic responses of circular ring-shaped barium titanate piezoelectric material have been investigated using the commercially available finite element software ABAQUS/CAE. To gain insight into the crystal morphology and to evaluate the purity of the material, a microscopic study was conducted using a scanning electron microscope and energy dispersive x-ray analysis. It is found that the maximum electrical potential of 6.43 V is obtained at a resonance frequency of 35 Hz by increasing the vibrating load. The results were then compared with the experimentally predicted data and the results agreed with each other.
Time−frequency analysis (TFA) is regarded as an efficient technique to reveal the hidden characteristics of the oscillatory signal. At present, the traditional TFA methods always construct the signal ...model in the time domain and assume the instantaneous features of the modes to be continuous. Thus, most of these approaches fail to tackle some specific kinds of impulselike signal, including shock and vibration waves, damped tones, or marine mammals. This article introduces a new method called generalized horizontal synchrosqueezing transform (GHST) to process the transient signal. A signal model defined in the frequency domain is used to deduce the GHST. Next, the new synchrosqueezing operator termed as group delay (GD) is proposed based on high-order Taylor expansions of the signal model. Finally, the modulus around ridge curves is rearranged from the original position to the estimated GD. Numerical results of a simulated signal demonstrate the precision of the GHST in terms of both readability of the time−frequency representation and reconstruction accuracy. Additionally, the proposed method is implemented to diagnose the fault in a rotary machine by analyzing the vibration signal. The validation demonstrates that the GHST performs better than other traditional TFA methods, and it is qualified for the online condition monitoring of the industrial mechanical system.
Advancements in the synchrosqueezing transform as a postprocessing time-frequency method have received considerable attention in the past few decades for the analysis of nonstationary signals. Many ...studies have focused on improving the accuracy of the estimated instantaneous frequency (IF). In some fields, the IF spectra of signals exhibit fast varying behavior or even some times parallel to the frequency axis. Thus, a majority of the existing methods may fail to adequately handle the transient signals such as guided waves and vibration waves. To address this problem, a new method called the horizontal synchrosqueezing transform (HST) is introduced in the present research study. By applying a local estimation of the group delay (GD), the proposed technique can yield a compact time-frequency representation for a transient signal while retaining its invertibility. For the purpose of validation, the proposed approach is implemented in both synthetic and real signals. The results are observed in a convincing manner in terms of the smaller value of the Rényi entropy and better reconstruction accuracy. The HST is supposed to be a reliable and accurate method for the analysis of transient signals with extensive usefulness.
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