On-line Measurement System Research Articles

Closed loop control system for dough fermentation based on image processing

AbstractDespite the importance of the proofing process in baking industry, no online measurement system is available so far, which can supervise this process step. This article presents the application of a model‐based tuned PID controller to the proofing process in bread baking. The work includes developing an on‐line monitoring system in order to measure volume evaluation of dough pieces during the proofing process and applying the corrective actions to minimize the size variation caused by alteration in amount of yeast added to the ingredients. The controller was tuned by an optimization method. For this purpose, a mathematical model representing the volume evaluation of dough pieces during proofing was identified, which allows an off‐line search for optimal parameters of the controller. The application of the proposed control strategy to an actual proofing chamber for controlling dough leavening during the proofing process was found to be successful.Practical applicationsBesides judging the right amount of proofing time, which is always challenging in the baking industry, alteration in ingredients and different starting states of the dough (normal dough frozen dough or thawed dough) will influence the required time for the proofing process. Any changes in time requirements in the process steps creates a backlog in the whole process, which will lead to inefficient manufacturing and low product quality. Online monitoring and automation process control of the proofing process is an alternative method to overcome these problems. The present research introduces an automated control system based on machine vision for controlling the proofing process in the baking industry. The automated control system is able to reduce the need for close monitoring and process adjustments by human operators, which leads to enhanced productivity and constant high product quality.

Detection of drinking water contamination event with Mahalanobis distance method, using on-line monitoring sensors and manual measurement data

Abstract Concerns about drinking water (DW) quality contamination during water distribution raise a need for real-time monitoring and rapid contamination detection. Early warning systems (EWS) are a potential solution. The EWS consist of multiple conventional sensors that provide the real-time measurements and algorithms that allow the recognizing of contamination events from normal operating conditions. In most cases, these algorithms have been established with artificial data, while data from real and biological contamination events are limited. The goal of the study was the event detection performance of the Mahalanobis distance method in combination with on-line DW quality monitoring sensors and manual measurements of grab samples for potential DW biological contamination scenarios. In this study three contamination scenarios were simulated in a pilot-scale DW distribution system: untreated river water, groundwater and wastewater intrusion, which represent realistic contamination scenarios and imply biological contamination. Temperature, electrical conductivity (EC), total organic carbon (TOC), chlorine ion (Cl-), oxidation–reduction potential (ORP), pH sensors and turbidity measurements were used as on-line sensors and for manual measurements. Novel adenosine-triphosphate and flow cytometric measurements were used for biological water quality evaluation. The results showed contamination detection probability from 56% to 89%, where the best performance was obtained with manual measurements. The probability of false alarm was 5–6% both for on-line and manual measurements. The Mahalanobis distance method with DW quality sensors has a good potential to be applied in EWS. However, the sustainability of the on-line measurement system and/or the detection algorithm should be improved.

Real‐Time Gas Quality Data for On‐Demand Production of Biogas

AbstractThe flexible production of biogas makes it a promising candidate to become the first renewable, on‐demand energy source. One appealing possibility to achieve an on‐demand supply of methane is to adjust the output of the biogas plant itself. As a consequence, the biological process will be partially overloaded and might fail. Hence, a prerequisite to avoid cost‐intensive failure is a fast, reliable, and cost‐efficient analytical technology for quickly determining the biogas quality. A low‐cost, robust, in‐situ online measurement system for the real‐time determination of carbon dioxide and methane concentrations is presented. The approach makes use of photoacoustic detectors, allowing for the development of gas sensors with reduced size that do not show cross‐sensitivities towards water vapor. The system's readings may be used as input for a novel type of control system that enables an active, demand‐driven control of actuators, such as feeding machinery or mixers.

Monitoring the Polymorphic Transformation of a Palm Kernel-Based Emulsion Using Ultrasound

Ultrasonic spectrometry was used to monitor the changes in polymorphism of palm kernel fat present in two tempered non-dairy emulsions with different globule sizes. Laser diffraction and differential scanning calorimetry (DSC) were performed to characterize the emulsions. X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) were used to determine the polymorphic state and solid fat content (SFC) of fully hydrogenated palm kernel oil during tempering of the emulsions. The ultrasonic instrument generated a “chirp” signal, which is characterized by its bandwidth. The ultrasonic measurements were carried out using two different pairs of transducers with different center frequencies, 2.25 and 0.5 MHz, and bandwidths. 3D plots were generated disputing time, frequency, and signal strength. The whole tempering process, from start to finish, was better characterized with the 2.25-MHz center frequency transducers. The ultrasonic velocity through the emulsions was always higher for the more stable β′ polymorph than for the α polymorph (p 0.05) on the ultrasound velocities obtained for the two globule sizes. Monitoring of polymorphic changes in emulsions using ultrasonic spectrometry could be used for an online measurement system for industrial manufacturing.

Thermography based online characterization of conductive thin films in large-scale electronics fabrication.

Flexible electronics is an emerging thin film based technology enabling completely new types of products and applications compared to conventional electronics. Since the quality of films defines the functionality of fabricated devices, the lack of suitable online manufacturing quality assessment tools has been identified to be a critical bottleneck while upscaling the volume and the yield of thin film electronics manufacturing. In order to solve that problem, a synchronized thermography (ST) based online measurement system was built. Applicability of proposed roll-to-roll compatible ST based system was demonstrated by characterizing a moving plastic film with conductive indium tin oxide on top. Obtained results show that ST can be utilized for online homogeneity characterization and sheet resistance estimation of large area thin films which are not possible with other existing methods.

Highly precise and real-time measurements of 13CO2/12CO2 isotopic ratio in breath using a 2 μm diode laser

Real-time breath gas analysis with high accuracy, precision and time resolution, as a promising, non-invasive, fast and reliable tool, is important in medical diagnostics. Especially stable isotopologues of carbon dioxide is applied to multiple research areas including the diagnosis of gastrointestinal diseases. Helicobacter pylori (H. pylori) is one of the most frequent bacterial infectious diseases in human beings and is now recognized as one of the key risk factors for chronic gastritis, peptic ulcers, stomach cancer and lymphoma. In contrast to traditional invasive tests, the most reliable non-invasive method in the diagnosis of the H. pylori infection is considered to be 13C-urea breath test which is implemented by measuring the 13CO2/12CO2 isotope ratio in human breath. Tunable diode laser absorption spectroscopy (TDLAS) has the advantages of fast response, low drift, good gas selectivity and high detection sensitivity, and it is very convenient to develop a high precision, real-time and online measurement system. A precision laser spectrometer for the measurement of CO2 isotope abundance in human breath (with CO2 concentration of 4%-5%) or high concentration gas is designed and evaluated based on TDLAS technology. The spectrometer contains a novel compact dense-pattern multipass cell with a small volume of 280 cm3 and an effective optical path length of 26. 4 m. The cell is in conjunction with a fiber-coupled distributed feedback diode laser operating at 2.008 μm. Wavelength modulation spectroscopy approach is used. The mass flow, pressure and temperature of the cell are actively controlled, and able to keep long-term stability. The influence of laser power fluctuation is eliminated by fitting the baseline with cubic polynomial to normalize the raw spectrum. Moving window regression is used to remove the influence of frequency drift on measuring isotope abundance. The system measurement precision is improved by wavelet denosing and Kalman filtering. The experimental results demonstrate that moving window regression method not only extends the stability time of the system but also improves the measurement precision of isotope abundance well, the wavelet denoising improves the signal-to-noise ratio by 2 times that by the method of multi-spectral average, the stability time of the system is 100 s given by Allan variance, and the measurement precision of CO2 isotope ratio is 0. 067‰ after Kalman filtering. The use of small multi-pass cell and the default of denoising devices make the system more portable and improve the real-time and online measurement performance of the system. In addition to the measurement of 13CO2/12CO2 isotope ratio in human breath, by replacing different lasers, the spectrometer can also be used to measure trace gas concentration and the stable isotope abundance of many gas molecules in atmosphere. Therefore, the spectrometer will have broad applications in the areas of medical diagnosis, carbon cycle study and environmental monitoring.

In-Pile Qualification of the Fast-Neutron-Detection-System

In order to improve measurement techniques for neutron flux assessment, a unique system for online measurement of fast neutron flux has been developed and recently qualified in-pile by the French Alternative Energies and Atomic Energy Commission (CEA) in cooperation with the Belgian Nuclear Research Centre (SCK•ECEN). The Fast-Neutron-Detection-System (FNDS) has been designed to monitor accurately high-energy neutrons flux (E > 1 MeV) in typical Material Testing Reactor conditions, where overall neutron flux level can be as high as 1015 n.cm-2.s-1 and is generally dominated by thermal neutrons. Moreover, the neutron flux is coupled with a high gamma flux of typically a few 1015 γ.cm-2.s-1, which can be highly disturbing for the online measurement of neutron fluxes. The patented FNDS system is based on two detectors, including a miniature fission chamber with a special fissile material presenting an energy threshold near 1 MeV, which can be 242Pu for MTR conditions. Fission chambers are operated in Campbelling mode for an efficient gamma rejection. FNDS also includes a specific software that processes measurements to compensate online the fissile material depletion and to adjust the sensitivity of the detectors, in order to produce a precise evaluation of both thermal and fast neutron flux even after long term irradiation. FNDS has been validated through a two-step experimental program. A first set of tests was performed at BR2 reactor operated by SCK•CEN in Belgium. Then a second test was recently completed at ISIS reactor operated by CEA in France. FNDS proved its ability to measure online the fast neutron flux with an overall accuracy better than 5%.

A system for online beam emittance measurements and proton beam characterization

A system for online measurement of the transverse beam emittance was developed. It is named 4PrOBεaM (4-Profiler Online Beam Emittance Measurement) and was conceived to measure the emittance in a fast and efficient way using the multiple beam profiler method. The core of the system is constituted by four consecutive UniBEaM profilers, which are based on silica fibers passing across the beam. The 4PrOBεaM system was deployed for characterization studies of the 18 MeV proton beam produced by the IBA Cyclone 18 MeV cyclotron at Bern University Hospital (Inselspital). The machine serves daily radioisotope production and multi-disciplinary research, which is carried out with a specifically conceived Beam Transport Line (BTL). The transverse RMS beam emittance of the cyclotron was measured as a function of several machine parameters, such as the magnetic field, RF peak voltage, and azimuthal angle of the stripper. The beam emittance was also measured using the method based on the quadrupole strength variation. The results obtained with both techniques were compared and a good agreement was found. In order to characterize the longitudinal dynamics, the proton energy distribution was measured. For this purpose, a method was developed based on aluminum absorbers of different thicknesses, a UniBEaM detector, and a Faraday cup. The results were an input for a simulation of the BTL developed in the MAD-X software. This tool allows machine parameters to be tuned online and the beam characteristics to be optimized for specific applications.

Accurate Online Measurement of Iron Concentration in Galvannealed Coating Layers by Shift of X-ray Diffraction Peak

The authors have developed a new online measurement system for the Fe concentration in galvannealed (GA) coating layers based on the proportionality between the X-ray diffraction (XRD) peak angle of the δ1 phase and the Fe concentration. The online system was realized by high speed measurement of the XRD peak angle by a one-dimensional detector and use of a correction algorithm for the angular error caused by the displacement of the GA strip surface from the measurement position. The XRD profile and displacement were simultaneously measured by the one-dimensional detector and a laser displacement meter, respectively. The high accuracy of this new online system was demonstrated in a continuous galvanizing line with GA steel strips of Si-added and Si-free base steels. The developed system showed sufficiently high accuracy even with the Si-added base steel, with which adequate accuracy could not be obtained with conventional online systems, based on the diffracted intensity of the Γ phase, due to the suppression of Γ phase formation. Since the δ1 phase is the major phase of the GA layers, the main advantage of the developed system is that its accuracy is less sensitive to the composition of the base steel. The developed system can be applied to other online measurement applications in the steel industry for various purposes such as measurement of phase transition, orientation, crystallinity, strain and other features.

参数主动控制的痕量气体实时在线测量系统

参数主动控制的痕量气体实时在线测量系统

On-line measurement system of high voltage insulator based on binocular stereo vision

On-line measurement system of high voltage insulator based on binocular stereo vision

A Review of Online Partial Discharge Measurement of Large Generators

Online partial discharge (PD) measurements have long been used as an effective means to assess the condition of the stator windings of large generators. An increase in the use of PD online measurement systems during the last decade is evident. Improvements in the detection capabilities are partly the reason for the increased popularity. Another reason has been the development of digital signal processing techniques. In addition, rapid progress is being made in automated single PD source classification. However, there are still some factors hindering wider application of the system, such as the complex PD mechanism and PD pulse propagation in stator windings, the presence of detrimental noise and disturbances on-site, and multiple PD sources occurring simultaneously. To avoid repetition of past work and to provide an overview for fresh researchers in this area, this paper presents a comprehensive survey of the state-of-the-art knowledge on PD mechanism, PD pulse propagation in stator windings, PD signal detection methods and signal processing techniques. Areas for further research are also presented.

Sulphur content estimation of Venezuelan heavy oil by fast neutron and gamma transmission technique

A compact and modern equipment for implementing the fast neutron and γ-ray transmission technique (FNGT) has been developed in order to estimate the sulphur content of crude oil. FNGT is employed for non- destructive analysis of different kinds of samples. The compact system presented in this work represents an improvement of our previous experimental set-up [1, 2]. It makes use of a 252Cf source, an EJ-301 liquid scintillator detector (2″ × 2″) with excellent n/γ discrimination capabilities, and modern nuclear electronics based on fast digitizers. The fast neutron and gamma transmission technique was employed to study a system for on-line sulphur concentration measurement in Venezuelan heavy sour oil. The range of sulphur concentrations investigated is between 0.1 and 6.5 wt%. The equipment performances and limitations are compared with those predicted by a Monte Carlo model built in GEANT4 v10.01. The results show the possibility to implement a compact unit for on-line determination of sulphur concentration in crude oil.

Microwave sensor technologies for food evaluation and analysis: Methods, challenges and solutions

Microwave sensor technology is widely accepted as a non-destructive and hygienic means for food evaluation and analysis. However, its applications concentrate on in-lab investigations, which are not widely applied for on-line measurement in food industry. Motivated by the rapid progress of microwave technologies and the lack of on-line measurement systems in industry, this paper aims to provide a comprehensive overview of microwave sensors for food measurement, define the technological gap, and suggest the potential solutions. With a brief introduction to the fundamentals, classification and analysis of the traditional methods and technologies are presented, followed by a discussion of calibration and decision-making methods. Based on the analysis of the cutting-edge microwave sensing technologies, the limitations and challenges facing the present studies are identified. Then, focusing on some new emerging technologies including Monolithic Microwave Integrated Circuits, antenna array and System on Chip Ultra-Wide Band pulse-based time domain systems, the feasibility and prospective of potential solutions in this particular area are suggested. In addition, integration of emerging Information and Communication Technologies (ICT) and new design concepts of the sensor system concerning the practical use for smart manufacturing are also illustrated. The potentiality of the suggested new emerging technologies and integration of ICT to satisfy future digitised industry will be inspirational and of interest to researchers of both microwave engineering and food sectors.

Design of On-Line Measurement System of Film Thickness Based on Infrared Technology

The thickness of the plastic film is an important physical index to the production of plastic. The measurement reslut relates directly to the companies’ economic benefit. This paper mainly introduces the digital signal processing in the detection system of film thickness. Through a perfect processing, the system can improve its SNR and finally get a high precision. Firstly, the principle and scheme was presented. After that, this paper mainly introduces the hardware implementation of the system. It includes analog filter circuit, AD sampling and digital filter. With the experimental verification, the system realizes the measurement of the film thickness on-line which can get the precision of micrometer. At present, the equipment has aready put into use by some companies.

Development of an on-line measurement system for water-soluble organic matter in PM2.5 and its application in China

Water-soluble organic matter (WSOM) represents a critical fraction of fine particles (PM2.5) in the air, but its changing behaviors and formation mechanisms are not well understood yet, partly due to the lack of fast techniques for the ambient measurements. In this study, a novel system for the on-line measurement of water-soluble components in PM2.5, the particle-into-liquid sampler (PILS)–Nebulizer–aerosol chemical speciation monitor (ACSM), was developed by combining a PILS, a nebulizer, and an ACSM. High time resolution concentrations of WSOM, sulfate, nitrate, ammonium, and chloride, as well as mass spectra, can be obtained with satisfied quality control results. The system was firstly applied in China for field measurement of WSOM. The mass spectrum of WSOM was found to resemble that of oxygenated organic aerosol, and WSOM agreed well with secondary inorganic ions. All evidence collected in the field campaign demonstrated that WSOM could be a good surrogate of secondary organic aerosol (SOA). The PILS–Nebulizer–ACSM system can thus be a useful tool for intensive study of WSOM and SOA in PM2.5.

Online measurement of particle charge density in a gas-solid bubbling fluidized bed through electrostatic and pressure sensing

Electrostatic phenomena widely exist in various olefin polymerization fluidized bed reactors, due to the continuous collision and friction of dielectric particles and the low-humidity reaction environment. The measurement of particle charge density is essential for monitoring and controlling the electrostatic level as well as probing the hydrodynamic characteristics in a fluidized bed. In this work, a non-intrusive online measurement system, employing ring-shaped sensing electrodes and a pressure transducer, is designed and implemented on a fluidized bed test rig. A modified model considering the influence of spatial sensitivity of the electrodes is proposed to predict the particle charge density in the fluidized bed, based on the measured induced electrostatic current and pressure drop signals. Experimental results have demonstrated that the induced electrostatic current and pressure drop signals show remarkable similarity, with the two PSDs both mainly distributed within 0.5–5Hz, which indicates close relationship between the two signals. The predicted particle charge density increases with the superficial gas velocity and decreases with the injection content of liquid anti-static agent (LAA), showing the same variation tendencies as that measured through a Faraday cup. When the electrode width is 20mm, the mean absolute relative errors for the direct method, area method and envelope method are 12.7%, 14.7% and 13.5%, respectively, indicating that the direct method is the most reliable signal processing approach proposed in this work.

Space charge distribution and leakage current pulses for contaminated glass insulator strings in power transmission lines

This study reports an investigation on space charge distribution and leakage current (LC) pulses of four units of glass insulators recently removed from service. Simulation works were conducted using finite element software and validated by laboratory experiments. The simulation and experimental results were found to be in good agreement when studying the space charge distribution pattern along the glass insulator string. It is evident that the LC waveform can be used to characterise the types of partial discharge according to their occurrence with respect to the AC supply. Thus, the proposed method is viable and reliable to be applied in an online measurement system.

On-line fresh-cut lettuce quality measurement system using hyperspectral imaging

In this study, an online quality measurement system for detecting foreign substances on fresh-cut lettuce was developed using hyperspectral reflectance imaging. The online detection system with a single hyperspectral camera in the range of 400–1000 nm was able to detect contaminants on both surfaces of fresh-cut lettuce. Algorithms were developed for this system to detect contaminants such as slugs and worms. The optimal wavebands for discriminating between contaminants and sound lettuce as well as between contaminants and the conveyor belt were investigated using the one-way analysis of variance (ANOVA) method. The subtraction imaging (SI) algorithm to classify slugs resulted in a classification accuracy of 97.5%, sensitivity of 98.0%, and specificity of 97.0%. The ratio imaging (RI) algorithm to discriminate worms achieved classification accuracy, sensitivity, and specificity rates of 99.5%, 100.0%, and 99.0%, respectively. The overall results suggest that the online quality measurement system using hyperspectral reflectance imaging can potentially be used to simultaneously discriminate foreign substances on fresh-cut lettuces.

HPLC와 DPPH radical 소거능 측정 방법의 결합에 의한 약용 식물 추출물의 항산화 활성 비교

Natural anti-oxidative compounds have important disease prevention and food preservation properties, in addition to anti-bacterial, anti-inflammation, anti-cancer, and skin whitening effects. High-performance liquid chromatography (HPLC), with an ultra vilolet (UV) detector coupled to a reverse phase C18 column and an online measurement system for 1, 1-diphenyl-2-picryl hydrazyl (DPPH) radicals, was used to search for potent antioxidative compounds in crude extracts. The online HPLCDPPH assay was then applied to confirm antioxidative compounds in water extracts from Radix of Pueraria lobata, Rhizoma of Zingiber officinale, Fructus of Chaenomeles sinensis, Cortex of Ulmus pumila, and Radix of Astragalus membranaceus. To determine the yields of the extracts, the Brix% of each extract solution was measured using a refractometer. When the relative DPPH radical scavenging ability values of the water extracts were compared with those of a positive control (ascorbic acid), the water extracts of P. lobata, C. sinensis, and U. pumila were 7.77%, 4.71%, and 4.19%, respectively. The results suggest that this method provides a useful assay for rapid measurement of DPPH radical scavenging abilities and conformation of antioxidative compounds in natural products. Moreover, it can reduce the time spent on the separation of active compounds from natural materials, such as medicinal plants, in addition to the use of reagents for separation.