Multipoint Data Research Articles

Volatile Organic Compounds Monitored Online at Three Photochemical Assessment Monitoring Stations in the Pearl River Delta (PRD) Region during Summer 2016: Sources and Emission Areas

Volatile organic compounds (VOCs) were monitored online at three photochemical assessment monitoring stations (MDS, WQS and HGS) in the Pearl River Delta region during the summer of 2016. Measured levels of VOCs at the MDS, WQS and HGS sites were 34.78, 8.54 and 8.47 ppbv, respectively, with aromatics and alkenes as major ozone precursors and aromatics as major precursors to secondary organic aerosol (SOA). The positive matrix factorization (PMF) model revealed that VOCs at the sites mainly came from vehicle exhaust, petrochemical industry, and solvent use. Vehicle exhaust and industrial processes losses contributed most to ozone formation potentials (OFP) of VOCs, while industrial processes losses contributed most to SOA formation potentials of VOCs. Potential source contribution function (PSCF) analysis revealed a north-south distribution for source regions of aromatics occurring at MDS with emission sources in Guangzhou mainly centered in the Guangzhou central districts, and source regions of aromatics at WQS showed an east-west distribution across Huizhou, Dongguan and east of Guangzhou, while that at HGS showed a south-north distribution across Guangzhou, Foshan, Zhaoqing and Yangjiang. This study demonstrates that multi-point high time resolution data can help resolve emission sources and locate emission areas of important ozone and SOA precursors.

Optimization of Vacuum-Microwave-Assisted Extraction of Natural Polyphenols and Flavonoids from Raw Solid Waste of the Orange Juice Producing Industry at Industrial Scale.

Orange pomace (OP) is a solid waste produced in bulk as a byproduct of the orange juice industry and accounts for approximately 50% of the quantity of the fruits processed into juice. In numerous literature references there is information about diverse uses of orange pomace for the production of high-added-value products including production of natural antioxidant and antimicrobial extracts rich in polyphenols and flavonoids which can substitute the hazardous chemical antioxidants/antimicrobials used in agro-food and cosmetics sectors. In this work and for the first time, according to our knowledge, the eco-friendly aqueous vacuum microwave assisted extraction of orange pomace was investigated and optimized at real industrial scale in order to produce aqueous antioxidant/antimicrobial extracts. A Response Surface Optimization methodology with a multipoint historical data experimental design was employed to obtain the optimal values of the process parameters in order to achieve the maximum rates of extraction of OP total polyphenols and/or total flavonoids for economically optimum production at industrial scale. The three factors used for the optimization were: (a) microwave power (b) water to raw pomace ratio and (c) extraction time. Moreover, the effectiveness and statistical soundness of the derived cubic polynomial predictive models were verified by ANOVA.

Processing of near-infrared multi-wavelength and multi-point data for glucose concentration measurement

Processing of near-infrared multi-wavelength and multi-point data for glucose concentration measurement

Microseismic Monitoring, Positioning Principle, and Sensor Layout Strategy of Rock Mass Engineering

Microseismic monitoring technology can start from the most initial stage of rock deformation and track and monitor the progressive failure process of rock mass from the fracture of rock blocks to the instability of rock mass. Thus, the scientific nature of monitoring work is greatly promoted, and the accuracy and advance of the prediction of engineering and geological disasters are improved. In this paper, the fracture and instability of rock can be analyzed by analyzing the microseismic signals produced by rock failure; The location of microseismic source can be determined by multipoint synchronous data acquisition to determine the time when each sensor (at least 5) receives microseismic signals; Combined with practical engineering experience for underground engineering in growth, heading tunnel, put forward only sensor arrangement to take mobile, follow the semienclosed layout network. We hope to give some reference to the researchers who are concerned with microseismic monitoring technology.

Mutation Information Extraction and Fluctuation Ratio Displacement Model of Step-like Landslides Based on Subdivided Monitoring Data

The multi-source, massive and subdivided monitoring data provide powerful data support for revealing the causal mechanism of complex geological disasters and improving the accuracy of time prediction. Especially in the sub-monitoring period by day and hour, the relationship between displacement and factors is more complicated, and the hidden information is more abundant. In this paper, multi-point and large sample data of step-like landslides in the Three Gorges Reservoir area are used to extract landslide mutation and establish a displacement prediction model. Firstly, the standardization, the IR model and the kNN regression model were used to obtain the principal curve reflecting the common characteristics of the displacement in the region. According to the multiplicative model of displacement decomposition, the landslide displacement incremental signal was decomposed into the product of the fluctuation ratio and the trend displacement increment by FFT filtering method. Finally, by fitting the fluctuation ratio of principal curve, the displacement function model consisting of the induced factor term and the state factor term was obtained. Taking the daily monitoring data of four bank slopes in Fengdu County for nearly 3 years as an example, the result show that the model was more in conformity with the evolution of the step-like landslide by daily monitoring than other displacement prediction methods.

RETRACTED: The application of multi-sensor target tracking and fusion technology to the comprehensive early warning information extraction of landslide multi-point monitoring data

• Application of multi-sensor target tracking fusion technology. • Proposes a spatiotemporal registration method and Ensemble Kalman Filte. • The test simulation is carried out by selecting 30 monitoring data. Landslide disasters are the second largest geological disaster activity in addition to earthquake disasters. They cause economic losses of up to several billion yuan each year, resulting in thousands of deaths and injuries. Therefore, it is important to monitor and alert landslide disasters. Significance. In addition, after the occurrence of landslides, a large amount of deposits will be created, which will further breed mudslides. The ability to qualitatively and quantitatively extract landslide information at the first time is particularly important for disaster prevention, mitigation, and disaster management. Therefore, the extraction of landslide information is a significant measure. At the same time, due to the limitations of sensors, how to organically fuse data from multiple sensors to achieve tracking performance that cannot be achieved by a single sensor has become the focus of research and attention on multi-sensor data fusion technology in the field of target tracking. Based on the above background, the research content of this paper is the application of multi-sensor target tracking fusion technology to achieve comprehensive warning information extraction of landslide multi-point monitoring data. This paper proposes a spatiotemporal registration method and Ensemble Kalman Filter (EnKF) for target tracking Algorithm, and the prediction model is established through optimization problem and target tracking. Finally, the test simulation is carried out by selecting 30 monitoring data of a monitoring point of a new construction project as the detection value. The experimental results show that when the moving target model is unknown in actual work, the polynomial. The order of the fitting and the boundary conditions of the spline fitting are not easy to give, but you can optionally use the sensor measurement data in the middle part and then use the spline fitting algorithm to obtain a better time registration effect; In terms of spatial registration, in the Z-axis direction, the measurement error of sensor A and sensor B is large, and the maximum value exceeds 2000 m. The maximum value of sensor A error between the measured values and theoretical values of radar A and B after registration is about 1000 m, which is the Z axis direction, and the maximum error of sensor B is about 1000 m, which is also the Z axis direction. The error has been significantly reduced. EnKF is better than the UKF algorithm under non-Gaussian noise conditions. The PF algorithm itself is suitable for nonlinear and non-Gaussian systems and has the best tracking performance.

Observational Study on the Impact of Large-Scale Photovoltaic Development in Deserts on Local Air Temperature and Humidity

As an important form of clean energy, photovoltaic (PV) power generation is entering a rapid development phase. Qinghai, China is located on the Qinghai-Tibet Plateau. It has sufficient sunlight and rich heat and light resources, includes a large area of the Gobi Desert, and has become China’s largest base for PV power generation. However, large-scale PV development in deserts changes the local surface energy distribution and impacts local microclimates. This study considered the Gonghe PV Power Plant in Qinghai as an example. Three monitoring stations were set up in the PV power plant, transition, and reference areas, and the influence of large-scale PV developments on the local air temperature and humidity was studied based on long-term, multi-point field observation data. The results showed that the overall daytime air temperature in the PV power plant had changed slightly (increased and decreased), while the night-time temperature dropped significantly. Specifically, in spring and summer, the daytime temperature increased slightly, with a maximum increase of 0.34 °C; in autumn and winter, the daytime temperature decreased slightly, with a maximum decrease of 0.26 °C; in all seasons, the night-time temperature decreased, with a maximum decrease of 1.82 °C during the winter night. The relative humidity in the PV power plant generally increased; except for a slight decrease in summer, the daytime and night-time relative humidity in spring, autumn, and winter always increased. The humidification in winter was the most significant, with increases of 5.00% and 4.76% for the transition and reference areas, respectively. The diurnal air temperature and relative humidity ranges in the PV power plant were greater than those outside the PV power plant. The results obtained in this field observation study could serve as a basis for quantitative evaluation of the microclimate effects of large-scale PV development in deserts and provide technical support for guiding the future planning and development of the PV industry.

Performance improvement of centrifugal compressors for fuel cell vehicles using the aerodynamic optimization and data mining methods

Centrifugal compressors are one of the most important auxiliary components in polymer electrolyte membrane fuel cell vehicles, which tend to operate at a narrow area with low specific speed. Here, the optimal design goals of centrifugal compressors are investigated on the basis of a lumped model for fuel cell systems. A three-dimensional multi-objective and multi-point aerodynamic optimization and data mining method for centrifugal compressors named ODM is presented via integrating a multi-island genetic algorithm, Reynolds-Average Navier-Stokes solver technique and self-organization map based data mining technique. Data mining indicates that compressor geometry would move to a small inlet diameter ratio and a narrow region of the outlet width ratio. Based on the optimization results, a centrifugal compressor for 100 kW fuel cell stack is manufactured. The experimental results show that the improvement of isentropic efficiency near low mass flow has been achieved, which indicates that the proposed ODM is effective in the performance improvement of centrifugal compressors for fuel cell vehicles.

Three‐Dimensional Representation of Large‐Scale Structures Based on Observations in Atmospheric Surface Layers

AbstractLarge amounts of synchronous multipoint measurement data were acquired from long‐term observations in high‐Reynolds‐number atmospheric surface layers (Reτ∼O(106)) at the Qingtu Lake observation array site. Based on these experimental data, the general shapes of three‐dimensional (3‐D) large‐scale coherent structures are constructed coupled with the symmetry of two‐point streamwise velocity correlations in the spanwise direction, where the spanwise symmetry is confirmed to be applicable in the atmospheric surface layer flow by experimental verification. The full extent of the 3‐D structure is much larger than a 2‐D slice at the condition point and increases significantly with the reference height in the logarithmic region. Moreover, the streamwise length and the spanwise width of the horizontal section are found to vary systematically with the relative height to the condition point. These variations are parametrized and can subsequently be used to infer the horizontal section at different relative heights. Then, a plausible empirical model is proposed by taking into consideration the streamwise shift caused by the inclination angle, and the 3‐D structure can be predicted by this model using the primary flow parameters and location information. This study contributes to a better understanding of dominant structures in the outer region of wall turbulence at high Reynolds numbers.

A Novel Multi-Points Laser Monitoring of Building Settlement and Its Risk Evaluation

Aiming at the defects of routine settlement measurement methods, such as complicated procedures, time-consuming and labor-intensive, high cost and low measurement accuracy, based on the analysis of existing engineering measurement technical requirements and specifications, a multi-point high precision and high efficiency based on laser reference is proposed. The automatic building settlement real-time monitoring system program gives the principle and system model of single-point settlement observation. The model of multi-point scanning settlement monitoring system and the model of multi-point network settlement monitoring system are designed, and their advantages and disadvantages are analyzed. We focus on the networked multi-point settlement monitoring system for network cumulative error analysis, and propose related evaluation and correction methods. The hardware schematic and software block diagram of the laser reference measurement and measurement system of the single point settlement acquisition system are given. Finally, the risk of subsidence state is quantitatively evaluated based on multi-point settlement monitoring data. The measurement error of this method is less than 300 µm, which can realize the monitoring and evaluation of the overall settlement.

Laboratory Evaluation of Railway Ballast Consolidation by the Non-Destructive Testing

The property of railway track to resist the irreversible deformation for a long-term operational loading considerably depends on the ballast layer. The ballast layer is the element of a railway track whose mechanical properties and state are formed in-situ with the help of the ballast cleaning, tamping and distributing machines. The varied properties of the ballast material to obtain the form during the maintenance and retain it during the operation are equally important for the ballast layer. The control over the processes of the ballast consolidation and deconsolidation by means of measurement methods could potentially provide great possibilities for improvement of its properties both during the maintenance and operation. The paper deals with an experimental study of the railway ballast consolidation and deconsolidation processes under the vibration loading of the sleeper. A non-destructive measurement method is proposed to investigate the distribution of the ballast consolidation along the sleeper. The method is based on the measurement of time of mechanical wave propagation. Modern low-cost sensors and powerful microcontroller techniques enable creating smart measurement systems for automatic multi-point data acquisition, online processing and statistical estimation of the ballast consolidation distribution.

High-Precision Imaging Algorithm for Highly Squinted SAR With 3D Acceleration

In conventional synthetic aperture radar (SAR) processing algorithms, it is generally assumed that the platform performs a uniform linear motion. However, if there is a three-dimensional acceleration during the flight, the motion trajectory will greatly increase the image processing complexity, especially in highly squinted scenarios. This paper proposes a high-precision imaging algorithm for highly squinted SAR with 3D acceleration. Firstly, the range history is extended by the Taylor series, and then a two-dimensional non-uniform fast Fourier transform (2D-NUFFT) is presented to focus the SAR image in range velocity domain. Moreover, as terrain matching is required in practice, the range-velocity image is further transformed into range-azimuth domain. The effectiveness of the proposed algorithm for highly squinted SAR imaging is verified with both simulation data for multi-point targets and experimental data for surface targets.

Thermal coefficients modification of high speed ball bearing by multi-object optimization method

Currently higher requirements on accurate thermal analysis of rolling bearing are put forward for high precision bearing-spindle system. To this end, this paper first presents a reverse solution method for thermal transfer analysis of high speed ball bearing, based on the internal multi-point temperature data by direct experimental method. Firstly, temperatures of bearing rotating components were obtained by a novel non-contact quantum dots fluorescence method and were treated as the target variables, and thermal convection coefficients and bearing temperature field obtained by traditional empirical formula were treated as the initial conditions. Parameters such as thermal convection coefficients between bearing inner ring/cage and lubricant, bearing housing and the air were optimized via the multi-objective optimization method. As evaluation, thermal elongation of a precision bearing-spindle was tested and the results prove the necessity of the coefficients optimization and the reliability of the presented method in this paper.

Design of Energy Saving Board Based on Wireless Technology

This system based on NRF905 transceiver chip technology, the design breaks down into three parts to design, consisting of a single-chip microcomputer system section, press section and display components. Divided into two parts, part of the system display, other lamp control ends. Street light control terminals and system monitor nrf905 multi-point wireless data transmission, controlled by host part, set the time, number lighting conditions have bright lights and other functions. NRF905 wireless transceiver chip for data sent and received. Finally, after experimental verification, this design can be combined effectively, strong anti-jamming ability, perfect function, can be used in street light control.

Brain remodeling after chronic median nerve compression in a rat model.

Carpal tunnel syndrome is the most common compressive neuropathy, presenting with sensorimotor dysfunction. In carpal tunnel syndrome patients, irregular afferent signals on functional magnetic resonance imaging are associated with changes in neural plasticity during peripheral nerve injury. However, it is difficult to obtain multi-point neuroimaging data of the brain in the clinic. In the present study, a rat model of median nerve compression was established by median nerve ligation, i.e., carpal tunnel syndrome model. Sensory cortex remodeling was determined by functional magnetic resonance imaging between normal rats and carpal tunnel syndrome models at 2 weeks and 2 months after operation. Stimulation of bilateral paws by electricity for 30 seconds, alternating with 30 seconds of rest period (repeatedly 3 times), resulted in activation of the contralateral sensorimotor cortex in normal rats. When carpal tunnel syndrome rats received this stimulation, the contralateral cerebral hemisphere was markedly activated at 2 weeks after operation, including the primary motor cortex, cerebellum, and thalamus. Moreover, this activation was not visible at 2 months after operation. These findings suggest that significant remodeling of the cerebral cortex appears at 2 weeks and 2 months after median nerve compression.

Multi-point LIBS measurement and kinetics modeling of sodium release from a burning Zhundong coal particle

A multi-point Laser-Induced Breakdown Spectroscopy (LIBS) method for quantitative measurement of sodium concentrations in the gas phase, the surface temperature and the particle diameter during the combustion of a Zhundong coal particle is presented. To obtain multi-point LIBS data, the laser focusing and signal collection optics are mounted on a translational platform which is able to traverse cyclically. With this setup multi-point LIBS measurements above a burning particle can be performed and the time-resolved sodium release process can be obtained. The results show that 42.2% of the total sodium mass is released during the burning of the Zhundong coal sample. For a 4 mm particle, in the char burnout stage sodium is released most strongly, i.e., 87% of the total released sodium mass, while in the de-volatilization and ash reaction stages the percentages are 5% and 8%, respectively. The atomic sodium and NaOH are the most favored species at chemical equilibrium in the plume according to CHEMKIN. The sodium release is found to be closely related to the particle burning stages by analyzing the sodium release, particle surface temperature and its diameter. A linear relationship is found between the residual sodium mass in the particle and the volume of the particle. The volatile sodium release rate obeys a two-step Arrhenius expression. Predictions by the developed two-step kinetics model agree well with the measured sodium release profiles in all the three coal-burning stages.

Particle and bioaerosol characteristics in a paediatric intensive care unit

The paediatric intensive care unit (PICU) provides care to critically ill neonates, infants and children. These patients are vulnerable and susceptible to the environment surrounding them, yet there is little information available on indoor air quality and factors affecting it within a PICU. To address this gap in knowledge we conducted continuous indoor and outdoor airborne particle concentration measurements over a two-week period at the Royal Children's Hospital PICU in Brisbane, Australia, and we also collected 82 bioaerosol samples to test for the presence of bacterial and viral pathogens. Our results showed that both 24-hour average indoor particle mass (PM10) (0.6–2.2μgm−3, median: 0.9μgm−3) and submicrometer particle number (PN) (0.1–2.8×103pcm−3, median: 0.67×103pcm−3) concentrations were significantly lower (p<0.01) than the outdoor concentrations (6.7–10.2μgm−3, median: 8.0μgm−3 for PM10 and 12.1–22.2×103pcm−3, median: 16.4×103pcm−3 for PN). In general, we found that indoor particle concentrations in the PICU were mainly affected by indoor particle sources, with outdoor particles providing a negligible background. We identified strong indoor particle sources in the PICU, which occasionally increased indoor PN and PM10 concentrations from 0.1×103 to 100×103pcm−3, and from 2μgm−3 to 70μgm−3, respectively. The most substantial indoor particle sources were nebulization therapy, tracheal suction and cleaning activities. The average PM10 and PN emission rates of nebulization therapy ranged from 1.29 to 7.41mgmin−1 and from 1.20 to 3.96pmin−1×1011, respectively. Based on multipoint measurement data, it was found that particles generated at each location could be quickly transported to other locations, even when originating from isolated single-bed rooms. The most commonly isolated bacterial genera from both primary and broth cultures were skin commensals while viruses were rarely identified. Based on the findings from the study, we developed a set of practical recommendations for PICU design, as well as for medical and cleaning staff to mitigate aerosol generation and transmission to minimize infection risk to PICU patients.

Multipoint analysis of compressive fluctuations in the fast and slow solar wind

AbstractCompressible turbulence in the solar wind is a topic of much recent debate. To understand the various compressive fluctuations at scales comparable to proton characteristic lengths, we use multipoint magnetic field and density data (derived from spacecraft potential which allows higher time resolution than is typically possible than with particle instruments) from the Cluster spacecraft when they were in undisturbed intervals of slow and fast solar wind. The application of the multipoint signal resonator technique is performed for the first time, to the analysis of scalar time series. Fluctuations in the measurements of electron density and in magnitude of the magnetic field (used as a proxy for compressible magnetic fluctuations) are used as inputs in addition to the traditional vector components of the magnetic field. This analysis is performed on two streams of solar wind, one which can be classed as a slow stream and one which can be classed as a fast stream to investigate the difference in the compressible components in the two types of wind. The recovered plasma frame frequencies for the incompressible component show low propagation speed in the plasma frame consistent with previous applications of the method, while the compressible components are more scattered, some with very high phase speeds. Based on these results, we propose a picture of compressive solar wind turbulence as a mixed state of (1) linear modes such as kinetic Alfvén, kinetic slow, and ion Bernstein modes; (2) coherent structures with very small intrinsic frequencies; and (3) nonlinear or sideband modes.

Quantitative analysis of a Hall system in the exhaust of asymmetric magnetic reconnection

AbstractTaking advantage of high‐resolution measurements from the MMS mission, we find evidence for a complete Hall system in the exhaust of asymmetric magnetic reconnection 40 Di downstream of the X line. The investigation of the fine structure of the Hall system reveals that it displays features in the exhaust similar to those reported previously in the ion diffusion region by simulations and observations. This finding confirms the importance of particle‐scale processes in the reconnection exhaust as well. On the magnetospheric side of the exhaust, electrons are strongly accelerated by parallel electric fields. This process significantly contributes to feed the Hall current system, resulting in a nonnegligible Hall magnetic field signature on this side despite an otherwise lower density. Calculation of the induced out‐of‐plane magnetic field by in‐plane currents (based on Biot‐Savart law) provides direct quantitative evidence for the process of Hall magnetic field generation by the Hall current system. A strong normal Hall electric field is present only on the magnetospheric side of the exhaust region, consistent with previous works. Multipoint data analysis shows that the ion pressure gradient in the ion momentum equation produces this Hall electric field. This global pattern of the Hall system can be explained by kinetic Alfvén wave theory.

Design and Implementation of Motor Control System Based on Industrial Internet

With the development of industrial automation system, industrial Internet by connecting each device even more important. It is based on ARM(Acorn RISC Machine) Cotex-M0 series processor and DSP(Digital Signal Processing) processor researched CAN(Controller Area Network) multi-point real-time data communication system. In ARM Cotex-M0 processor as the master chip, DSP processor as the slave chip. The system uses TCP/IP to transfer data from a client to ARM, ARM using a CAN bus to transmission data to the DSP, and build the modern industrial Internet, realize the motor drive control.