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A novel microfluidic paper-based analytical device with dual colorimetric and electrochemical detection (dual μPAD) was developed for the assessment of transferrin saturation (TSAT) in samples from ischemic stroke patients. TSAT was calculated from the ratio between transferrin-bound iron, which was colorimetrically measured, and the total iron-binding capacity, which was electrochemically measured. To this end, a μPAD was smartly designed, which integrated both colorimetric and electrochemical detection reservoirs, communicating via a microchannel acting as a chemical reactor, and with preloading/storing capabilities (reagent-free device). This approach allowed the dual and simultaneous determination of both parameters, providing an improvement in the reliability of the results due to an independent signal principle and processing. The μPADs were validated by analyzing a certified reference material, showing excellent accuracy (Er ≤ 5%) and precision (RSD ≤ 2%). Then they were applied to the analysis of diagnosed serum samples from ischemic stroke patients. The results were compared to those provided by a free-interference method (urea-PAGE). Impressively, both methods exhibited a good correlation (r = 0.96, p < 0.05) and no significant differences were found between them (slope 1.0 ± 0.1 and the intercept 1 ± 4, p < 0.05), demonstrating the excellent accuracy of our approach during the analysis of complex samples from ischemic stroke patients, using just 90 μL of clinical samples and taking less than 90 min in comparison with the 18 hours required by the urea-PAGE approach. The developed fully integrated colorimetric-electrochemical μPAD is a promising ready to use reagent-free device for the point-of-care testing of TSAT, which can be used to assist physicians in the fast diagnosis and prognosis of ischemic strokes, where the decision-time is crucial for the patient's survival. [ABSTRACT FROM AUTHOR]

This report describes for the first time the development of paper-based enzymatic reactors (PERs) for the detection of glucose (Glu) in artificial serum sample using a 3D printed batch injection analysis (BIA) cell coupled with electrochemical detection. The fabrication of the PERs involved firstly the oxidation of the paper surface with a sodium periodate solution. The oxidized paper was then perforated with a paper punch to create microdisks and activated with a solution containing N -hydroxysuccinimide (NHS) and N -(3-dimethylaminopropyl)- N ′-ethylcarbodiimide hydrochloride (EDC). Glucose oxidase (GOx) enzyme was then covalently immobilized on paper surface to promote the enzymatic assay for the detection of Glu in serum sample. After the addition of Glu on the PER surface placed inside a plastic syringe, the analyte penetrated through the paper surface under vertical flow promoting the enzymatic assay. The reaction product (H 2 O 2 ) was collected with an electronic micropipette in a microtube and analyzed in the 3D BIA cell coupled with screen-printed electrodes (SPEs). The overall preparation time and the cost estimated per PER were 2.5 h and $0.02, respectively. Likewise the PERs, the use of a 3D printer allowed the fabrication of a BIA cell within 4 h at cost of $5. The coupling of SPE with the 3D printed cell exhibited great analytical performance including repeatability and reproducibility lower than 2% as well as high sampling rate (30 injections h −1 ) under low injection volume (10 μL). The limit of detection (LD) and linear range achieved with the proposed approach was 0.11 mmol L −1 and 1–10 mmol L −1 , respectively. Lastly, the glucose concentration level was successfully determined using the proposed method and the values found were not statistically different from the data achieved by a reference method at confidence level of 95%. [ABSTRACT FROM AUTHOR]

Abstract: Electrochemical treatment of organic pollutants is a promising treatment technique for substances which are resistant to biodegradation. In this study an electrochemical treatment based on the principle of anodic oxidation was used to treat paper mill effluent from Rakta''s Pulp and Paper Company where rice straw is used to produce paper pulp. Experiments were carried out in a cylindrical agitated vessel lined with lead sheet as anode while a concentric cylindrical stainless steel sheet screen was placed as a cathode. The effect of current density, pH, NaCl concentration, impeller rotational speed and temperature on the rate of color and COD removal was studied. The results showed that the use of electrochemical technique reduces the COD from an average value of 5500 to 160. The percentage color removal ranged from 53% to 100% depending on the operating conditions. Energy consumption calculation shows that energy consumption ranges from 4 to 29kWh/m3 of effluent depending on the operating conditions. The experimental results proved that the electrochemical oxidation is a powerful tool for treating paper mill effluents where rice straw is used as a raw material. [Copyright &y& Elsevier]

Abstract: Sulfide can be removed from wastewater and recovered as elemental sulfur using an electrochemical process. Recently, we demonstrated this principle of product recovery on synthetic feeds. Here, we present a lab scale electrochemical reactor continuously removing sulfide from the effluent of an anaerobic treatment process operated on paper mill wastewater. The effluent contained 44 ± 7 mg of sulfide-S L−1. Sulfide was reduced to 8 ± 2 mg-S L−1, at a removal rate of 0.845 ± 0.133 kg-S m−3 of total anodic compartment (TAC) d−1. The removed sulfide was recovered (75 ± 4% recovery) as pure concentrated alkaline sulfide/polysulfide solution, from which solid elemental sulfur was obtained. The electrochemical sulfide removal was not affected by different soluble constituents or particulate materials present in the wastewater. However, over time sulfide removal decreased due to biological sulfur reduction using the organics present in the wastewater. Therefore, a periodic switching strategy between anode and cathode was developed. Biofilm formation was avoided as the pH of the cathode solution increased to inhibitory levels during cathodic operation, while still allowing full recovery of the sulfur as end product. [Copyright &y& Elsevier]

Abstract: The choice of the cathode material is crucial for every bio-cathode microbial fuel cell (MFC) setup. The commonly used biocathode materials, Graphite felt (GF), carbon paper (CP) and stainless steel mesh (SSM) were compared and evaluated in terms of current density, power density, and polarization. The maximum current density and power density of the MFC with GF-biocathode achieved 350 mA m−2 and 109.5 mW m−2, which were higher than that of the MFC with CP-biocathode (210 mA m−2 and 32.7 mW m−2) and the MFC with SSM-biocathode (18 mA m−2 and 3.1 mW m−2). The polarization indicated that the biocathode was the limiting factor for the three MFC reactors. Moreover, cyclic voltammetry (CV) showed that the microorganisms on the biocathode played a major role in oxygen reduction reaction (ORR) for GF- and CP-biocathode but SSM-biocathode. Electrochemical impedance spectroscopy suggested that GF biocathode performed better catalytic activity toward ORR than that of CP- and SSM-biocathode, also supported by CV test. Additionally, the MFC with GF-biocathode had the highest Coulombic Efficiency. The results of this study demonstrated GF was the most suitable biocathode for MFCs application among the three types of materials when using anaerobic sludge as inoculums. [Copyright &y& Elsevier]

Investigation of cell signaling pathways is important for the study of pathogenesis of cancer. However, the related operations used in these studies are time consuming and labor intensive. Thus, the development of effective therapeutic strategies may be hampered. In this work, gel-free cell culture and subsequent immunoassay has been successfully integrated and conducted in a paper-based microreactor array. Study of the activation level of different kinases of cells stimulated by different conditions, i.e., IL-6 stimulation, starvation, and hypoxia, was demonstrated. Moreover, rapid screening of cell signaling cascades after the stimulations of HGF, doxorubicin, and UVB irradiation was respectively conducted to simultaneously screen 40 kinases and transcription factors. Activation of multi-signaling pathways could be identified and the correlation between signaling pathways was discussed to provide further information to investigate the entire signaling network. The present technique integrates most of the tedious operations using a single paper substrate, reduces sample and reagent consumption, and shortens the time required by the entire process. Therefore, it provides a first-tier rapid screening tool for the study of complicated signaling cascades. It is expected that the technique can be developed for routine protocol in conventional biological research laboratories. [ABSTRACT FROM AUTHOR]

Abstract: The reductive removal of haloacetic acids (HAAs) in a three-dimensional electrochemical continuous reactor with Pd-granular activated carbon (Pd-GAC) particles as fixed filler and Pd-modified carbon paper (Pd-C) as cathode was studied in this research. Pd-C electrode was prepared from PdCl2 via electrodeposition onto carbon paper. Pd-GAC particles were prepared by the impregnation of Pd2+ ions onto GAC. Efficient electrocatalytic reduction of HAAs in this reactor was exhibited. Effects of current density, initial HHAs concentration, and hydraulic retention time on the HHAs removal were investigated. Under the current density of 0.3 mA/cm2, HAAs with initial concentration of 120 μg/L were reduced to be less than 60 μg/L with hydraulic retention time of 20 min. Electron transfer and HAAs diffusion both played an important role in controlling the electro-reduction process under the conditions of current density less than 0.6 mA/cm2 with an initial HAAs concentration ranging from 120 to 600 μg/L. However, the HAAs diffusion became the primary rate-limiting step when the current density was higher than 0.6 mA/cm2. The Pd0 and Pd2+ species were detected by X-ray photoelectron spectroscopy. The stability of the electrochemical reactor in the reduction removal of HAAs was also exhibited. [Copyright &y& Elsevier]

Enzymatic hydrolysis of sludge from a bleached tissue mill generates glucose that can be sold as a product or sent to an ethanol plant. Hydrolysis rates using enzymes from two sources are reported, and a configuration for the industrial conversion of sludge to glucose is proposed. The system combines a set of stirred tank reactors with ash removal and membrane filtration to give a glucose concentrate. The economics of the conversion are attractive. [ABSTRACT FROM AUTHOR]

Abstract: Pig waste (PW) and paper sludge (PS) possess complementary properties that can be combined for successful anaerobic digestion. Biochemical methane potential (BMP) tests revealed that a PW:PS 3:1 (v/v) ratio had the highest normalized CH4–COD removal (54%), while PS had the lowest value (11%) and PW had 44%. Batch BMP tests revealed a significant decrease in lag times for methane production in the order of PW:PS 1:3 (14days)

Abstract: Paper and cardboard stand for the major biodegradable organic fraction of most of municipal solid waste (MSW). This article aims at discussing the possible positive impact of a thin shredding of this fraction on its biodegradability under mesophilic anaerobic conditions, either for landfilling or for digestion in industrial reactors. For that purpose, BMP tests were performed on two types of paper and cardboard mixtures: one sorted from a complex landfill French MSW income, one built from source separated papers and cardboards. For both of these substrates, comparison was made between assays on large pieces of waste and assays on tiny shredded waste (powder particles of less than 1mm diameter). For the second substrate, assays at two different inoculation levels were performed. All results are discussed both in terms of maximal methane conversion yields and in terms of kinetic rates. The main conclusion is that shredding does not improve methane potential of paper and cardboard, neither the biogas production rates. This leads the authors to put forward the hypothesis that shredding does not significantly either increase enzyme accessibility to cellulose nor favor the surface bacterial colonization, although it strongly affects the macrostructure of the waste. [Copyright &y& Elsevier]

Abstract: A fundamental goal of second generation ethanol production is to increase the ethanol concentration to 10% (v/v) or more to optimise distillation costs. Semi simultaneous saccharification and fermentations (SSSF) were conducted at small pilot scale (5L) utilising fed-batch additions of solid shredded copier paper substrate. Early addition of Accellerase® 1500 at 16FPU/g substrate and 30U/g β-glucosidase followed by substrate only batch addition allowed low final equivalent enzyme concentrations to be achieved (3.7FPU/g substrate) whilst maintaining digestion. Batch addition resulted in a cumulative substrate concentration equivalent to 65% (w/v). This in turn resulted in the production of high concentrations of ethanol (11.6% v/v). The success of this strategy relied on the capacity of the bioreactor to perform high shear mixing as required. Further research into the timing and number of substrate additions could lead to further improvement in overall yields from the 65.5% attained. [Copyright &y& Elsevier]

A generalized kinetic model resulting from several modifications of the one originally known as the Series Event Model has been applied to describe three different disinfection processes and compare their efficiencies. The work was performed in a well-defined, versatile batch reactor employing Escherichia colias a subrogate bacteria. The following systems were studied: (i) UVC radiation alone, (ii) hydrogen peroxide alone and (iii) UVC radiation combined with hydrogen peroxide. The kinetic parameters of the three models were determined. Within the range of studied operating conditions, the use of UVC alone has shown to produce the best results. [ABSTRACT FROM AUTHOR]

The experimental results obtained for the photocatalytic degradation of a model organic dye in an annular slurry reactor are analyzed with the aid of a mathematical model. The model is used also to study the effects on the performances of many operative conditions: flow rate, photocatalyst concentration, power of the lamp, size of the photocatalytic particles, dimensions of the reactor. The investigation demonstrates that the rate of the process is often limited by the radiant energy transfer and that some simple rules can be followed in order to optimize different yields and the observed rate of reaction. [ABSTRACT FROM AUTHOR]

Kinetic studies with Pseudomonas aeruginosa using actinides and lanthanides indicated a two-phase metal uptake. Equilibrium uptake data of all the metals studied could be fitted to Langmuir as well as Freundlich models. The Scatchard plots showed that there were mainly two types of receptor sites on the cell walls of P. aeruginosa having different affinities for the metal ions. EDAX studies revealed replacement of calcium and magnesium ions from biomass by sorbed metal. Around 85% of the adsorbed metal could be released using citrate buffer (pH 4.0, 0.2 M). Metal desorption was as high as 95% with HCl. Continuous flow studies using P. aeruginosa immobilized on activated alumina gave 80% enhancement of lanthanum removal efficiency compared to the control column. Regeneration of the column resulted in 80% of its initial capacity in succeeding cycles. Journal of Industrial Microbiology & Biotechnology (2000) 25, 1–7. [ABSTRACT FROM AUTHOR]

We investigate a model for an activated sludge process that contains a chemical reactor unit attached to a bioreactor. Inside the chemical reactor unit, a process takes place which increases the decay coefficient of heterotrophic biomass. This mimics a number of experimental techniques which are used to decrease the mass of sludge. Such techniques are of growing interest as the activated sludge process produces large volumes of sludge; the costs associated with its disposal are significant. Our primary interest is to investigate how the operation of the chemical reactor unit changes the steady-state concentrations of both the total suspended solids within the biological reactor and the chemical oxygen demand in the effluent stream. The operation of a chemical reactor unit always increases the value of chemical oxygen demand in the effluent stream. The behaviour of the total suspended solids is more complicated; in some cases, the operation of the CRU increases the total suspended solids. For a fixed value of the chemical oxygen demand in the influent stream, we show that both the percentage reduction in the total suspended solids and the chemical oxygen demand in the effluent stream are increasing functions of the soluble substrate in the feed. The same trends occur when the influent composition is fixed, and the disintegration rate inside the chemical reactor unit is increased. This leads to dichotomic behaviour, decreasing the total suspended solids increases the chemical oxygen demand in the effluent stream. There are two consequences of this behaviour. Firstly, there are some waste streams that can not be cleaned using the process configuration considered in this paper. Secondly, the imposition of a target value for the chemical oxygen demand in the effluent stream imposes a maximum achievable reduction in the total suspended solids in the biological reactor. Higher reductions can not be achieved without causing the chemical oxygen demand in the effluent stream to exceed the target value. [ABSTRACT FROM AUTHOR]

Rotary furnaces are used as reactors to intensify chemical processes between the powder and gas atmosphere around it. The furnace rotation leads to relative motion and dilation of the powder layers, facilitating gas access. The paper is devoted to the modeling of nickel oxide powder behavior in a rotary furnace to estimate the contribution of furnace rotation speed to gas permeability when the nickel oxide granules are reduced in a hydrogen atmosphere. Discrete element modeling of powder granules in a rotary furnace was conducted employing Altair EDEM commercial software to estimate the powder gas permeability at different stages. The powder bed in a horizontal cylindrical rotary furnace was modeled as a packing of identical spherical granules with diameters equal to those of the nickel oxide granules. The furnace rotation led to periodic oscillations of the powder along the furnace wall with an amplitude that gradually diminished to some steady value. Gas permeability of the powder bed was evaluated through the porosity function, derived from the Carman permeability equations. Greater gas permeability resulting from significant powder dilation was observed only in active shear zones on the powder bed surface and in the contact area between the powder and the furnace wall. Sizes of the shear zones depended on the furnace rotation speed but never exceeded several granule diameters for all rotation speeds. The efficiency of a rotary furnace as a chemical reactor was shown to be determined not only by the powder dilation but also by the regeneration rate for the powder bed surface. The regeneration rate can be calculated and changes nonlinearly with the furnace rotation speed. [ABSTRACT FROM AUTHOR]

Searching an optimal value of the neural emulator adaptive rate presents a great problem. Indeed, a new scheme of neural emulators based on the Particle Swarm Optimization (PSO) algorithm for nonlinear systems is adopted in this paper. The main goal of this approach consists in adjusting effectively the neural emulator adaptive rate in order to accelerate the convergence speed and to improve the precision degree. The obtained results are compared with those reached with an intelligent tuning strategy. An experimental validation of the new emulator adaptation is carried on chemical reactor. Efficiency of the proposed method is proved according to the obtained performances. [ABSTRACT FROM AUTHOR]

Copyright of Diamond & Abrasives Engineering is the property of Zhengzhou Research Institute for Abrasives & Grinding and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Measuring temperature inside chemical reactors is crucial to ensuring process control and safety. However, conventional methods face a number of limitations, such as the invasiveness and the restricted dynamic range. This paper presents a novel approach using ultrasound transducers to enable accurate temperature measurements. Our experiments, conducted within a temperature range of 28.8 to 83.8 °C, reveal a minimal temperature accuracy of 98.6% within the critical zone spanning between 70.5 and 75 °C, and an accuracy of over 99% outside this critical zone. The experiments focused on a homogeneous environment of distilled water within a stainless-steel tank. This approach will be extended in a future research in order to diversify the experimental media and non-uniform environments, while promising broader applications in chemical process monitoring and control. [ABSTRACT FROM AUTHOR]

The article discusses various reports published within the issue, including one on laser-based accelerators, one on plasma-based chemical reactors, and one on electron beam based microwave devices.

The method of mathematical modelling that takes into account various physical systems, such as various tele-communications, High voltage transmission, and various chemical reactors, ultimately produced a variety of solutions for bigger order complex mathematical models with higher order. Order reduction is essential for such higher order systems (HOS) for reducing mathematical complexity for designing controllers. In order to improve upon several existing model order reduction approaches, the goal of this paper is to solve difficult higher order models using Differential Pole Cluster Mixed (DPM) Techniques. The accuracy of the proposed reduced model has been made via comparing step responses of original and reduced order models. In order to improve upon several existing model order reduction approaches. The higher order system PID Controller has been made using the proposed reduced-order approach. [ABSTRACT FROM AUTHOR]

Personal teaching experiences are discussed using an analysis logic diagram which stresses experimental efforts and the need to make students aware of uncertainties in any significant problems they will face. The critical issues are illustrated using a reactor analysis which has been made into an interactive design game for the Web. The analysis logic is also briefly illustrated for mass contactor and heat exchanger analysis. © 2011 American Institute of Chemical Engineers AIChE J, 2012 [ABSTRACT FROM AUTHOR]

The current state of mixed ionic–electronic conducting ceramic membrane technology presents significant advancements with potential applications in various fields including solid oxide electrolyzers, fuel cells, hydrogen production, CO2 reduction, and membrane reactors for chemical production and oxygen separation. Particularly in oxygen separation applications, optimal conditions closely align with the conditions of oxygen-rich air streams emitted from the anode of solid oxide co-electrolyzers. This paper describes and analyzes a novel integrated heat recovery system based on mixed ionic–electronic conducting membranes. The system operates in two stages: firstly, oxygen is separated from the anode output stream using mixed ionic–electronic conducting membranes aided by a vacuum system, followed by the heat recovery process. Upon oxygen separation, the swept gas stream is recirculated at temperatures near thermoneutral conditions, resulting in performance improvements at both cell and system levels. Additionally, an oxygen stream is generated for various applications. An Aspen HYSYS® model has been developed to calculate heat and material balances, demonstrating the efficiency enhancements of the proposed system configuration. [ABSTRACT FROM AUTHOR]

Oxidation flow reactors (OFRs) using OH produced from low-pressure Hg lamps at 254nm (OFR254) or both 185 and 254nm (OFR185) are commonly used in atmospheric chemistry and other fields. OFR254 requires the addition of externally formed O3 since OH is formed from O3 photolysis, while OFR185 does not since O2 can be photolyzed to produce O3 and OH can also be formed from H2O photolysis. In this study, we use a plug-flow kinetic model to investigate OFR properties under a very wide range of conditions applicable to both field and laboratory studies. We show that the radical chemistry in OFRs can be characterized as a function of UV light intensity, H2O concentration, and total external OH reactivity (OHRext, e.g., from VOCs, NOx, and SO2). OH exposure is decreased by added external OH reactivity. OFR185 is especially sensitive to this effect at low UV intensity due to low primary OH production. OFR254 can be more resilient against OH suppression at high injected O3 (e.g., 70 ppm), as a larger primary OH source from O3, as well as enhanced recycling of HO2 to OH, make external perturbations to the radical chemistry less significant. However if the external OH reactivity in OFR254 is much larger than OH reactivity from injected O3, OH suppression can reach two orders of magnitude. For a typical input of 7 ppm O3 (OHRO3 = 10 s-1) ten-fold OH suppression is observed at OHRext ~ 100 s-1, which is similar or lower than used in many laboratory studies. This finding may have important implications for the interpretation of past laboratory studies, as applying OHexp measurements acquired under different conditions could lead to over an order-of-magnitude error in the estimated OHexp. The uncertainties of key model outputs due to uncertainty in all rate constants and absorption cross-sections in the model are within ±25% for OH exposure and within ±60% for other parameters. These uncertainties are small relative to the dynamic range of outputs. Uncertainty analysis shows that most of the uncertainty is contributed by photolysis rates of O3, O2, and H2O and reactions of OH and HO2 with themselves or with some abundant species, i.e., O3 and H2O2. Using HOx-recycling vs. destructive external OH reactivity only leads to small changes in OHexp under most conditions. Changing the identity (rate constant) of external OH reactants can result in substantial changes in OHexp due to different reductions in OH suppression as the reactant is consumed. We also report two equations for estimating OH exposure in OFR254. We find that the equation estimating OHexp from measured O3 consumption performs better than an alternative equation that does not use it, and thus recommend measuring both input and output O3 concentrations in OFR254 experiments. This study contributes to establishing a firm and systematic understanding of the gas-phase HOx and Ox chemistry in these reactors, and enables better experiment planning and interpretation as well as improved design of future reactors. [ABSTRACT FROM AUTHOR]

Purpose: This paper presents a novel concept for design of concrete support system for chemical reactors used in refineries and petrochemical plants. Graphical method is described that can be used to size the concrete base and piling system. Recommendations are also provided to optimize the parameters required for the design. The procedure is illustrated for design of two reactor models commonly used in gas recovery units. Design/methodology/approach: Design space representation for the foundation system is described for chemical reactors with variable heights. The key points of the design graph are extracted from the numerical finite element models. The reactor load is idealized at discrete points to transfer the loads to the piles. Bilateral spring system is used to model the soil restrains. Findings: The graphical approach is economical and provides the design engineer the flexibility to select the foundation parameters from wide range of options. Practical implications: The concept presented in the paper can be utilized by engineers in the industry for design of chemical reactors. It must be noted that little guidelines are currently available in practice addressing the structural design aspects. Originality/value: A novel concept is presented in this paper based on significant industrial design experience of reactor supports. Using the described method leads to significant cost savings in material quantity and engineering time. [ABSTRACT FROM AUTHOR]

This paper focuses on the effects of heat radiation and chemical reactions on naturally occurring convective MHD flow that conducts electricity when there is an induced magnetic field present between two vertical walls having a porous medium between them. An analytical method is adopted to investigate the impacts of all pertinent parameters concerning the presented multi-physics problem. With the aid of relevant conversions, the nonlinear PDEs are remodeled into nonlinear ODEs.The effects of radiation parameters, Hartmann number, Hall current, chemical reaction and porosity parameters are scrutinized on velocity components, induced magnetic field, and current density. The results predict that the temperature profile decreases as the radiation factor rises, whereas the induced magnetic field would exhibit the opposite pattern. The profiles of component velocity get more intense for high rates of the porosity parameter. Additionally, profiles of induced magnetic field surges with elevated chemical reaction parameter values have been noted. The presented approach is very promising for multi-physics phenomena like chemical reactors and solar thermal devices. [ABSTRACT FROM AUTHOR]

In this paper, an adaptive neural network (NN) fault-tolerant controller is designed for the leader-following consensus control problem of a nonlinear multi-agent systems (MASs) under the complex effect of actuator fault, state time-delay, asymmetric output error constraint and the lumped uncertainty. Firstly, by using an asymmetric barrier Lyapunov function (BLF), output errors are ensured to meet the asymmetric output error constraint requirements. Then, Lyapunov–Krasovskii (L–K) functional and Young's inequality are combined to tackle state time-delay. Radial basis function neural network (RBFNN) is employed to approximate the unknown nonlinear function. Furthermore, adaptive technique is utilized to solve actuator fault. Based on the Lyapunov stability theory, the semi-global bounded stability of closed-loop system is proved. Finally, the validity of the designed control strategy is verified by compared simulation and the application of the two-stage chemical reactors. [ABSTRACT FROM AUTHOR]

Methanol is considered a key and platform compound to produce high value‐added chemicals, and it could contribute to energy transition, decreasing the dependence of fossil fuels. This paper presents a methanol synthesis simulation over a commercial Cu/ZnO/Al2O3, which is used at industrial scale. With the aim of exploring renewable raw materials as alternative to synthesize this alcohol, synthesis gas was obtained as a starting mixture from gasification of residual coffee pulp, which is an agro‐industrial waste widely generated in coffee producing countries. Currently, the raw materials most used to obtain methanol are natural gas and coal, so the use of agro‐industrial waste as a raw material would achieve greener methanol production. Design of experiments and ANOVA were applied to obtain results with statistical significance. Residual coffee pulp gasification conditions and reaction temperature were the controlled variables, while methanol production was selected as a response one. The simulation runs and ANOVA were analyzed and compared with the literature reports, and it was observed that methanol production is possible avoiding the catalyst deactivation. For the best obtained conditions, the profiles along the reactor of chemical species molar fraction, stochiometric number, methanol production and pressure drop were shown. [ABSTRACT FROM AUTHOR]

Controlled manipulation of microscale robotic devices in complex fluidic networks is critical for various applications in biomedical endovascular sensing, lab-on-chip biochemical assays, and environmental monitoring. However, achieving controlled transport and active retention of microscale robots with flow sensing capability has proven to be challenging. Here, we report the dynamic tweezing of an anisotropic magnetic microrobot in a rotating magnetic trap for active retention and localized flow sensing under confined fluidic conditions. We reveal a series of unconventional motion modes and the dynamics of the microrobot transporting in a confined fluidic flow, which manifest themselves as transitions from on-trap centre rolling to large-area revolution and off-trap centre rolling with varying rotating frequencies. By retaining the robot within the magnetic trap and its motion modulated by the field frequency, the offcentre rolling of the microrobot endows it with crucial localized flow sensing capabilities, including flow rate and flow direction determination. The magnetic microrobot serves as a mobile platform for measuring the flow profile along a curved channel, mimicking a blood vessel. Our findings unlock a new strategy to determine the local magnetic tweezing force profile and flow conditions in arbitrary flow channels, revealing strong potential for microfluidics, chemical reactors, and in vivo endovascular flow measurement. [ABSTRACT FROM AUTHOR]

The paper describes all the steps of a teaching activity dealing with Process Dynamics and Control and focused on the students' use of the Control Station® simulation software. After a short software description, the paper discusses the methodology developed for coupling theoretical lecturing and practical PC-lab class, the way of involving students and the use of an interactive software environment to present automatic control of illustrative process plants. These latter comprise unit operations and simple equipment from chemical, biochemical, pharmaceutical and food industries as actual examples of abstract systems and mathematical formalisms introduced for studying processes in the context of dynamics and control. Two Project Works, which were developed by students using Control Station® and discussed by them, are presented as examples. The outcome of this 8-year teaching experience is analyzed on the basis of the number of Project Works annually delivered, the auto-evaluation tests, the final exam scores as well as the relevant answers yearly provided by the students through the Course Evaluation Forms. The final statistical results are positive. [ABSTRACT FROM AUTHOR]

This paper deals with a new weight-updating algorithm using Lyapunov stability theory (LST) for the training of a neural emulator (NE), of nonlinear systems, connected by an autonomous algorithm inspired from the real-time recurrent learning (RTRL). The proposed method is formulated by an inequality-constraint optimization problem where the Lagrange multiplier theory is used as the optimization tool. The contribution of this paper is the integration of the LST into the Lagrange constraint function to synthesize a new analytical adaptation gain rate satisfying the asymptotic stability of the NE and providing good emulation performances. To confirm the good performances and the convergence ability of the proposed adaptation algorithm, a numerical example and an experimental validation on a chemical reactor are proposed. [ABSTRACT FROM AUTHOR]

The drift-flux model (DFM) is of practical importance for analyzing gas–liquid flow in various applications, such as chemical reactors and nuclear power plants. This paper aims at developing an accurate flow-regime-independent DFM for estimating the void fractions of two-phase downward inclined flow. The effect of flow channel inclination on void fraction for downward two-phase flows was investigated comprehensively. First, 2868 data for void fractions of gas–liquid two-phase flows were summarized from 12 sources. The inclination angle ranged from 0° to 90°. Then, the existing drift-flux models were reviewed comprehensively. The existing models had poor predictive performance in terms of the whole experimental database. Therefore, a theoretically supported drift-flux model for downward inclined two-phase flow was established based on a deeper understanding of two-phase flow behavior. The influence of channel inclination angles on the distribution parameters and drift velocities was determined quantitatively. A total of 87.8% of estimated void fractions were within ±20% errors of experimental void fractions. The mean relative deviation, md, was −2.04%. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The dynamics of the tubular chemical reactor with mass recycle was examined. In such a system, temperature and concentrations may oscillate chaotically. This means that state variable values are then unpredictable. In this paper, it has been shown that despite the chaos, the behavior of such a reactor can be predictable. It has been shown that this phenomenon can occur in two cases. The first case concerns intermittent chaos. It has been shown that intermittent outbursts can occur at regular intervals. The second case concerns transient chaos, i.e. a situation when chaos occurs only for a certain period of time, e.g. only during start-up. This phenomenon makes it impossible to predict what will occur in the reactor in the nearest time, but, makes it possible to precisely determine the values of the variables even in the distant future. Both of these phenomena were tested by numerical simulation of the mathematical model of the reactor. [ABSTRACT FROM AUTHOR]

A multi-faceted energy intensive technology that can be used for water disinfection and synthesis of electrolysed water (EW) is the need of the hour to achieve a sustainable post COVID 19 water management strategy. Direct sunlight driven processes are legislatively green technologies and hold the key in environmental sustenance. The development of a laboratory proto type reactor powered by a photovoltaic module for the treatment open source river water is described in this paper. This paper reports on the efficacy of the developed proto type technology for multipurpose application namely: (1) the production of Electrolysed water (EW) in a cost efficient manner using direct sunlight and (2) the removal of organic impurity from water using direct sunlight without the use of any photo catalyst or membrane. The prototype reactor utilizes chemical spray pyrolysis deposited highly photo-conducting indium sulphide thin films grown on fluorine doped tin oxide (F:SnO2) substrate (coated using chemical spray pyrolysis technique in-house) as the photo electrode. Dissolved organic matter arising in river water has distinctive fluorescence properties, and this research has utilized it to identify dissolved organic substances in both random samples and treated water. The work proves that photovoltaic module powered electrolytic reactors consisting of In2S3 electrodes can be used for treatment of river water. A diaphragm free, energy intensive route for the production of electrolysed water with the use of non-hazardous NaCl as the electrolyte has been demonstrated here. We conclude that In2S3 electrodes can be used for non-photo catalytic reduction of humic-derived impurities in river water. These results are also encouraging on the prospects of treating Nitrates present in the river water. The likes of techniques as described in this report that do not use photo catalyst or membranes may pave way for real time photovoltaic module powered floating reactors that can decontaminate water bodies on a large scale. The technique used by us demonstrates that a chlorine free route can be optimized for the synthesis of EW eliminating the production of large amounts of wastewater with high levels of biological oxygen demand (BOD). [ABSTRACT FROM AUTHOR]

This paper presents a new method of actuator fault detection based on the functional observer approach for a two‐stage chemical reactor with disturbance, parameter uncertainty, and time‐delay. The mechanism analysis method is used to model the system and the observer is designed. The exogenous disturbance can be decoupled completely from the error dynamic systems by letting some relevant constraints ensure the robustness of the residual generator. Stability conditions are obtained by using the Lyapunov–Krasovskii functional approach in the form of linear matrix inequalities (LMIs). Finally, simulation results are given to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper examines a new Conditional Source-term Estimation (CSE) implementation in which an integral inversion is performed for species mass fractions without any chemistry tabulation. To tackle the numerical stiffness due to chemistry, a constant-pressure chemical reactor is considered in conditional space. The objective of this work is to investigate this new method in CSE by comparing its numerical performance (accuracy of predictions and computational efficiency) with previous CSE implementations using tabulated chemistry. For the first time, the constraints for mass and mixture fraction conservation in conditional space are included in the inversion process. The investigation is performed in a Reynolds Averaged Navier-Stokes (RANS) framework using a well-documented turbulent flame with detailed measurements in conditional and physical spaces for many reacting scalars. A chemical mechanism including 16 species and 35 reactions is incorporated. CSE predictions of conditional and Favre averaged temperature and different species mass fractions are analysed. CSE with full chemistry performs as well as CSE with tabulated chemistry, if not slightly better. Numerical errors are discussed. The new CSE implementation is made possible by the proposed numerical treatment of stiffness due to chemistry and first-order Tikhonov regularisation technique with additional physical constraints. The new approach is found to be more CPU intensive than CSE with a pre-tabulation technique, but as a preliminary analysis, the computational cost of CSE with direct integration of a chemical mechanism appears to be much smaller than the run time associated with CMC for a similar set-up. Further investigation is required to refine this initial conclusion. These results open new opportunities towards CSE simulations that involve fuel blends and more complex operating conditions for example with spray and multi-stream inlets with non-uniform compositions for which accurate chemistry tabulations are difficult to generate. [ABSTRACT FROM AUTHOR]

This paper proposes an indirect adaptive control method based on recurrent neural networks. To achieve satisfactory closed-loop performances, a neural emulator (NE) and a neural controller (NC) adapting rates are established using the multiobjective particle swarm optimization (MOPSO) algorithm. The proposed MOPSO algorithm has been designed to minimize, simultaneously, two separated objective functions: the emulation and the tracking errors. The proposed approach guarantees that the NE tracks the system dynamics within a short time window. Consequently, it provides for the suggested control structure useful information to synthesize optimal adaptive rates of the NE and NC. To validate the effectiveness of the proposed MOPSO algorithm, a numerical example and an experimental validation on a chemical reactor are proposed. [ABSTRACT FROM AUTHOR]

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This paper addresses the problem of dissipative-based stabilization for fractional-order nonlinear control systems with uncertainties, time-delay, external disturbances, actuator faults, actuator and sensor saturations. Specifically, a non-fragile reliable dynamic output feedback controller is designed for the purpose of stabilization of the addressed system. Due to the effect of saturation phenomena occurring in both the actuator and sensor, the anti-windup loops framed with the help of the observer design are incorporated into the controller design. Some sufficient conditions are formulated in terms of linear matrix inequalities by choosing a suitable Lyapunov function thereby assuring the dissipative-based stabilization. The derived results are thus validated by two numerical examples including the practical model of two-stage chemical reactor. [ABSTRACT FROM AUTHOR]

The chattering phenomenon is one of the most pervasive problems in sliding mode control (SMC), especially for discrete time applications. In this paper, we propose a new discrete output feedback second order sliding mode control (DOF2SMC). The design of this controller is based on the Linear Matrix Inequalities (LMI) approach. Then, an adaptive switching gain (ASG) is incorporated into the discontinuous part of the controller to obtain good closed loop performance in terms of tracking and reducing chattering in the case of systems subject to internal and external disturbances. Simulation results of a steer-by-wire (SBW) system show the effectiveness of the proposed DOF2SMC with ASG. To validate, once again, the performance of the proposed control system, an experimental validation on a transesterification reactor is presented. The obtained results show good closed loop performance. [ABSTRACT FROM AUTHOR]