Ultra-wideband (UWB) radar is an important remote sensing tool of life detection or a non-contact monitor of the vital signals. By processing the received UWB pulse echoes reflected from the body, ...different signals corresponding to heart activity and breathing, corrupted by body motion and the environment noise, are wanted to be separated clearly. However, the heartbeat signal is so tiny that it is covered by breathing harmonics and clutters. At the same time, since the frequencies of the vital signals are very close, usually around 1 Hz, it is difficult to apply an ordinary frequency filter to separate them apart. This problem induces that the vital signal detection method, usually, only detects the large breath signal, not the heartbeat signal. To solve this problem, a novel method is provided, in this paper, to extract the heartbeat and the breath information simultaneously. The method uses the feature time index with the first valley peak of the energy function of intrinsic mode functions (FVPIEF) calculated by pseudo bi-dimension ensemble empirical mode decomposition method and extracts the vital signals by the ensemble empirical mode decomposition (EEMD). Both simulation and experiment results evidently show that the proposed FVPIEF based two-layer EEMD method is effective for separating the small heartbeat signal from the large breath signal and significantly improves the evaluation of heart and breathing rates in both hold-breathing and breathing conditions.
Sunset yellow (SY) is a synthetic colorant which can cause allergies, diarrhea and other symptoms in sensitive people. When ingested too much, it can accumulate in the body and cause damage to the ...kidneys and liver. Therefore, the content of SY in food must be strictly controlled. In order to regulate their use and ensure food quality, simple and cost-effective methods need to be developed to identify them. In this experiment, fluorescent silicon nanoparticles (SiNPs) were prepared by a one-step method, which is simple, mild and less time-consuming. The fluorescent SiNPs prepared had good thermal stability, excellent salt resistance and pH stability. SY effectively quenched the fluorescence of SiNPs by fluorescence resonance energy transfer when added to the system as an interfering substance. The method had a good linear relationship in the range of SY concentration of 0.050 – 14.0 μg mL−1 and the detection limit is 0.023 μg mL−1. The established sensor was applied to the detection of SY in beverages, and the recovery rate was 93.8 – 102.4%. Based on the excellent selectivity and sensitivity of the method, it could provide a convenient way for the detection of SY in food samples.
Soil stability and aggregates are important drivers of soil fertility and microbial diversity and are highly vulnerable to land degradation. However, the role of soil aggregates in driving the ...responses of microbial functional diversity and multiple ecosystem services and functions (multifunctionality) to further degradation (e.g., fertilization) remains largely unexplored and poorly understood. In this study, we used soils from long-term experiments involving inorganic and organic fertilization treatments to investigate the role soil aggregates (microscale) play in driving microbial functional gene diversity (via GeoChip) and the activity of multiple extracellular enzymes in an agricultural ecosystem. We found that microbial functional gene diversity has a significant and positive relationship with soil multifunctionality, which is enhanced in soil aggregates by organic fertilizer but is reduced by inorganic fertilizer. We also found that soil aggregate fractions indirectly controlled multiple ecosystem functions via changes in functional diversity. Smaller soil aggregates with higher resource availability (carbon and nitrogen) supported more ecological functions than larger aggregates under contrasting fertilizer management regimes. Soil multifunctionality is regulated by the differences in resource availability and not by microbial functional gene composition, which suggests that microbial functional diversity contributed more to multifunctionality than gene composition. Random forest analysis and structural equation modeling indicated that soil carbon and nitrogen and microbial functional diversity together determined the multifunctionality, whereas soil traits have more standardized total effects than functional diversity. Our study highlights that soil aggregation stratifies soil nutrition and microbial functional diversity, which leads to the differentiation of aggregate ecosystem multifunctionality.
•Microbial functional diversity positively regulates soil multifunctionality.•Microbial diversity contributes more to multifunctionality than taxonomic traits.•Soil aggregate size may indirectly and negatively determine multifunctionality.•Organic and inorganic fertilizers have opposite effects on multifunctionality.•Soil nutrition and functional diversity together control multifunctionality.
An effective method for the determination of 49 pesticide residues and 17 mycotoxins in wine by a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method and ultrahigh‐performance ...liquid chromatography–tandem mass spectrometry was developed. The target compounds were extracted with 1% (v/v) formic acid–acetonitrile, and no cleanup steps were required. The extracts were separated on a C18 chromatographic column (2.1 mm × 50 mm, 1.7 µm) with acetonitrile and water with 0.2% formic acid solution and ammonium acetate (10 mM) as the mobile phases under gradient elution at a flow rate of 0.2 mL/min. The determination was conducted using electrospray ionization in positive ion mode with multiple reaction monitoring. The analytes were quantified by comparison with matrix‐matched standard solutions. The good linearities were obtained in the range of 0.05 to 500.0 µg/kg, and the correlation coefficients were all greater than 0.9935. The average recoveries of the 66 target compounds ranged from 69% to 119%, and the RSDs were in the range of 1% to 10%. The limits of detection were in the range of 0.05 to 20.0 µg/kg. The method was proved to be rapid, selective, sensitive, and stable, and it has been applied to analysis of 64 wine samples.
The aim of this study was to evaluate the influence of clarification treatments on volatile composition and aromatic attributes of wine samples. 'Italian Riesling' icewines from the Hexi Corridor ...Region of China were clarified by fining agents (bentonite (BT) and soybean protein (SP)), membrane filtration (MF), and centrifugation (CF) methods. The clarity, physicochemical indexes, volatile components, and aromatic attributes of treated wines were investigated. Both the fining agents and mechanical clarification treatments increased the transmittance and decreased the color intensity of icewine samples. Bentonite fining significantly influenced the total sugar content, total acidity and volatile acidity. Total acidity decreased 2-3.5% and volatile acidity 2-12%. MF showed the greatest influence on total phenol content, decreasing the initial content by 12%, while other treatments by less than 8%. Volatile analysis indicated that both the categories and contents of volatile compounds of wine samples decreased. MF treatment showed the most significant influence, while SP fining showed much lower impact. Odor activity values indicated the compound with the highest odor activity in Italian Riesling icewines was β-damascenone. For this compound, BT and SP did not show significant differences, however, in MF and CF it decreased by 20% and 63%, respectively. Furthermore, with high impact on aroma were: ethyl hexanoate which reduced by 20-80% especially in MF; rose oxide which extremely reduced in MF and undetected in BT, SP, and CF; isoamyl acetate which reduced by 3-33% and linalool decreased by 10-20% and undetected for BT. Principle component analysis indicated that icewine clarified by different methods could be distinguished and positively correlated with odor-active compounds. Floral and fruity were the dominant aroma series in icewine samples followed by fatty, earthy, spicy, vegetative and pungent flavor. The total odor active value of these series significantly (
< 0.5) decreased in different clarification treatments. Sensory evaluation showed similar results, but the SP and CF wine samples achieved better sensory quality. This study provides information that could help to optimize the clarification of ice wines.
The aim of this study is to develop and validate an improved analytical method for the simultaneous quantification of 20 types of mycotoxins in grapes and wines. In this research, the optimization of ...tandem mass spectrometer (MS/MS) parameter, ultra-high pressure liquid chromatography (UHPLC) separation, and QuEChERS procedure, which includes wine/water ratio, the amount and type of salt, clean-up sorbent, were performed, and the whole separation of mycotoxins was accomplished within 7 min analyzing time. Under optimum conditions, recoveries ranged from 85.6% to 117.8%, while relative standard deviation (RSD) remained between 6.0% and 17.5%. The limit of detection (LOD, 0.06⁻10 μg/L) and the limit of quantification (LOQ, 0.18⁻30 μg/L) were lower than those permitted by legislation in food matrices, which demonstrated the high sensitivity and applicability of this efficient method. Finally, 36 grapes and 42 wine samples from the Hexi Corridor region were analyzed. Penicillic acid (PCA), mycophenolic acid (MPA), cyclopiazonic acid (CPA), fumonisin B1 (FB1) and zearalenone (ZEN) were detected in a small number of grape samples with lower concentrations between 0.10 μg/L and 81.26 μg/L. Meanwhile, ochratoxin A (OTA), aflatoxin B2 (AFB2), MPA, CPA, and ZEN were detected in some wine counterparts with concentrations ranged from 0.10 μg/L to 4.62 μg/L. However, the concentrations of the detected mycotoxins were much lower than the maximum legal limits set of other products.
In an array system of wave energy converters (WECs), hydrodynamic interactions between the WECs occur through the absorption, radiation, and diffraction of waves. The main objective of this study was ...to analyse the hydrodynamic interactions between floating point-absorbing WECs and the influence of this interaction on the power performance and fatigue life of the WECs’ mooring lines. The hydrodynamic and structural response of the WEC systems were analysed primarily using potential flow theory, the Morison equation, and continuum mechanics theory. Four 2-WEC models and two 10-WEC models, among which different separating distances and mooring configurations were considered, were investigated. The models were simulated for various environmental loading conditions. The results from each simulation were evaluated in terms of the power performance of each WEC, accumulated fatigue damage in each mooring line, and the levelised cost of energy (LCoE). The hydrodynamic interactions show a larger impact on the 10-WEC simulation models. To account for the hydrodynamic interactions in the simulations using the 10-WEC models, the fatigue damage in the mooring lines is varied at an average of 15% and a maximum of an order of magnitude difference. A similar comparison of power performance showed an approximate difference in the results of 10%. The LCoE calculation of the 10-WEC array system showed LCoE values that range from −40% to +200% relative to the simulations that did not consider the hydrodynamic interaction effects. Comparatively, the LCoE calculation of the 2-WEC model either decreased by 17% or increased by 23% when the hydrodynamic interaction was included in the simulation model.
•Coupled response analysis is performed to study the power performance of WEC arrays and fatigue life of moorings.•Hydrodynamic interaction between WECs in an array has a strong influence on the fatigue damage in moorings.•The interaction effect contributes to a reduction of the LCoE of a 10-WEC array by 40% or to an increase by a factor of 3.
Microarc oxidation (MAO) is a surface modification process that is often adopted to produce a hard oxide layer on magnesium alloys to improve their corrosion resistance and wear resistance. However, ...under continual corrosion, the characteristic porous microstructure of MAO coatings provides diffusion paths that allow corrosive species to penetrate the coatings and react with the substrate underneath. Therefore, the present study investigated the modification of the microstructure of MAO coatings when adding TiO2 nanoparticles to a fluoride-containing silicate electrolyte system under the bipolar current mode. The results indicate that as the concentration of TiO2 nanoparticles increased, the quantity of rutile (TiO2) incorporated in the MAO coating increased, which led to the coating exhibiting an elevated hardness and a color change from white to gray-black. When the TiO2 concentration in the electrolyte was increased from 2.5 to 7.5 g/L, the total impedance of the MAO coating in electrochemical impedance spectroscopy analysis increased from 107 to >600 kΩcm2, which indicates that the corrosion resistance of the coating increased with the number of defects on it decreased. The addition of TiO2 enhances the photocatalytic properties of MAO coatings. However, excessive addition of TiO2 can lead to an adverse effect on the wear resistance of MAO coatings.
•The microstructure and phases of MAO coating can be controlled by TiO2 addition.•Higher concentration of TiO2 promotes the formation of rutile phases.•Higher concentration of TiO2 improves corrosion resistance.•Excessive addition of TiO2 can lead to an adverse effect on the wear resistance.
A case study of a point-absorber wave energy converter (WEC) system is presented. The WEC system forms an array, with several WECs located around a central hub to which they are each connected by a ...short, free-hanging power cable. The objective of the study is to analyse the dynamic characteristics and estimate the fatigue life of the power cable which is not yet in use or available on the commercial market. Hence, a novel approach is adopted in the study considering that the power cable’s length is restricted by several factors (e.g., the clearances between the service vessel and seabed and the cable), and the cable is subject to motion and loading from the WEC and to environmental loads from waves and currents (i.e., dynamic cable). The power cable’s characteristics are assessed using a numerical model subjected to a parametric analysis, in which the environmental parameters and the cable’s design parameters are varied. The results of the numerical simulations are compared and discussed regarding the responses of the power cables, including dynamic motion, curvature, cross-sectional forces, and accumulated fatigue damage. The effects of environmental conditions on the long-term mechanical life spans of the power cables are also investigated. Important cable design parameters that result in a long power cable (fatigue) service life are identified, and the cable service life is predicted. This study contributes a methodology for the first-principle design of WEC cables that enables the prediction of cable fatigue life by considering environmental conditions and variations in cable design parameters.
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