Conventional Mode Of Operation Research Articles

Process design and simulation of methyl isobutyl ketone (MIBK) dehydration by batch distillation: A study on unit configuration and operational policies

Heteroazeotropic batch distillation of methyl isobutyl ketone-water binary mixture is investigated, seeking a reliable operation for dehydration of methyl isobutyl ketone (MIBK). The dynamic batch distillation module (BatchSep) of the commercial package Aspen Plus V.12.1® is applied for simulations. An initially fed unit at atmospheric pressure is simulated from the heating-up step until it reaches the desired MIBK purity of 99.8 wt%. Three configurations, namely conventional batch distillation unit (Mode I), batch distillation unit with decanter (Mode II), and a simple distillation unit (Mode III), are compared in a wide range of operating conditions. The effects of condenser temperature and the number of theoretical stages are also examined. According to the results, applying a decanter (Mode II) with a return fraction of over 0.75 for the MIBK-rich phase and below 0.4 for the aqueous phase provides higher MIBK recovery than the maximum achievable value in a conventional unit (Mode I), with almost no increase in process time. A perfect decanter offers an almost complete MIBK recovery, which is about 5% over the maximum value by conventional units (Mode I). Moreover, cutting the reflux (Mode III) offers the fastest way to the desired product but provides the lowest MIBK recovery value. The aqueous phase return fraction does not significantly impact MIBK recovery, but if it exceeds 0.5, it remarkably affects the process time/energy cost. When maximum MIBK recovery rate/minimum energy cost is desired, applying a decanter (Mode II) with a return fraction above 0.5 for the MIBK-rich phase and below 0.55 for the aqueous phase yields a higher production rate and a lower energy cost per unit quantity of product compared to the best achievable values for a conventional unit (Mode I). A perfect decanter improvesproductionrateandenergyefficiencyby8 %overthe best case in a conventionalunit (ModeI). Also, operation without reflux (Mode III) is preferred over a conventional operation (Mode I) with a total return fraction over 0.7 due to its superior energy efficiency and production rate.

Understanding Heterogeneous Passenger Route Choice in Municipal Rail Transit with Express and Local Trains: An Empirical Study in Shanghai

The express/local mode of municipal rail transit provides passengers with multiple alternatives to achieve more efficient and superior travel, in contrast to the conventional all-stop operation mode. However, the various route choices (including direct express trains, direct local trains, or transfers) covering different passenger groups pose a significant challenge to passenger flow assignment. To understand route choice behavior, it is crucial to measure the passenger heterogeneity (variability in individual and trip attributes) in order to propose targeted solutions for operation schemes and service planning. This paper proposes a hybrid model by integrating structural equation modeling and the mixed logit model under express/local mode to estimate the impact of passenger heterogeneity on route choice. An empirical study with revealed preference and stated preference surveys carried out in Shanghai revealed how individual and trip attributes quantitatively impact the sensitivity of factors in route choice. The results show that age and trip purpose are more significant factors. Compared to the control group, the probability of express trains is reduced by 10.22% for the elderly and by 11.36% for non-commuters. Our findings can provide support for more reasonable operation schemes and more targeted services.

TMI and polarization static energy transfer in Yb-doped low-NA PM fibers.

In this work, we conduct experimental investigations of transverse mode instabilities (TMI) in a large mode area ultra-low numerical aperture polarization maintaining fiber amplifier. This fiber is few mode in the slow-axis (conventional operation mode), but single mode in the fast-axis. We test the stability of the output beam by changing the input polarization angle and systematically investigate the transverse mode instability threshold in the two principal polarization axes. The lowest TMI threshold at 300 W was found when the input polarization angle was aligned parallel to the slow-axis. Detuning the input polarization angle from the slow-axis led to increased TMI thresholds. For input polarization angle of 90° (parallel to the fast-axis), the output signal was stable up to 475 W and further scaling was limited by the available pump power. However, for fast-axis operation a lower polarization ratio compared to slow-axis operation was observed as well as an unexpected static energy transfer from the fast-axis into the slow-axis above 400 W.

Leveraging autonomous vehicles crash narratives to understand the patterns of parking-related crashes

Autonomous vehicles (AVs) parking has been a subject of interest from various researchers; however, the focus has been on the parking demand, algorithm, and policies, while the safety aspect has received less attention, perhaps due to the lack of AV crash data. This study evaluated the magnitude and pattern of AV parking-related crashes that occurred between January 2017 and August 2022 in California. The study applied descriptive analysis, unsupervised text mining, and supervised text mining (Support Vector Machine, Naïve Bayes, Logitboost, Random Forest, and Neural network) with resampling techniques. It was indicated that parking-related crashes constitute about 16% of all AV crashes, most of them are likely to impact the AV on the rear or left side. The unsupervised text mining results showed that AVs in the conventional mode of operation, reversing, and parallel parking are among the key themes associated with parking-related crashes. The Support Vector Machine, Logitboost, Random Forest, and Neural network showed relatively high prediction accuracy. The important features from these supervised text mining approaches were conventional mode, reservsing, passenger vehicle, parallel parking, which confirm the preliminary findings in the unsupervised text mining. The implications of the findings to operators and policymakers are included in the study. Findings from this paper could be used to introduce measures to reduce AV parking-related crashes.

Comparative study of multiple-mode collaborative operation strategy and traditional heat and power decoupling technologies for cogeneration system based on GTCC

This study proposes a multiple-mode collaborative operation strategy for the first time, which integrates compressor inlet air heating mode, gas turbine interstage extraction mode, and back pressure heating mode. This operation strategy can improve the peak shaving flexibility of the cogeneration system based on gas turbine combined cycle (GTCC). This article uses Ebsilon software to simulate cogeneration system based on GTCC under different heat and power decoupling technologies and obtain the heat and power operation region. The peak performance of different heat and power decoupling technologies on heating characteristic days are analyzed. Meanwhile, the impact of objective power load changes is studied. The results show that during the whole heating season, compared with the conventional operation mode without heat and power decoupling technology, the multiple-mode collaborative operation strategy, electric boiler (EB) technology, and heat storage tank (HST) technology are adopted, and the renewable energy integration of the cogeneration system based on GTCC are increased by 1.16 × 105 MW, 1.37 × 105 MW and 5.65 × 104 MW, respectively. In addition, When the objective power load is 197.5 MW or 120 MW, taking into account the integration of renewable energy, natural gas consumption, and system benefits, the multiple-mode collaborative operation strategy is the optimal choice.

A collaborative cuckoo search algorithm with modified operation mode

Cuckoo search (CS) is a nature-inspired algorithm that has shown its favorable potential for solving complex optimization problems. Nevertheless, there is a lack of effective information sharing between individuals in CS, which would doubtless limit its achievable performance. While several CS variants have considered this issue, they commonly strengthen the information sharing in just one of the two search parts (i.e., global and local search parts). In this paper, to further address the above issue and to get a more rational allocation of the workloads of global search and local search, a new CS variant called collaborative CS with modified operation mode (CCSMO) is proposed. One novelty is that a collaborative mechanism is presented to strengthen the information sharing and collaboration between individuals in both search parts, and correspondingly, two new iterative strategies are introduced respectively for global search and local search. Another novelty is that the conventional operation mode adopted by almost all existing CS-based algorithms is modified for more rationally allocating the workloads of global search and local search. To validate the performance of CCSMO, extensive experiments and comparisons between CCSMO and 17 state-of-the-art algorithms are made on two popular test suites from IEEE Conference on Evolutionary Computation (CEC). Besides, the algorithm is also applied to solve three engineering design problems and one large-scale combined heat and power economic dispatch problem. The results demonstrate that CCSMO can offer highly competitive performance. Additionally, the time complexity, search behavior, modification effectiveness, and parameter sensitivity of CCSMO are also evaluated.

Albizia lebbeck leaf extracted natural antioxidant doped biodiesel–diesel blend in low heat rejection diesel engine

Natural antioxidants are available in various biomass substances which can be used for improving human health and fuel oxidation stability. This research is aimed at using a natural antioxidant powder obtained from Albizia lebbeck leaves powder to improve the oxidation stability of an optimal Jatropha methyl ester (JME)-diesel blend. Initially, Albizia lebbeck leaves are characterized by x-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy for their oxidant behavior. The optimal JME diesel blend (JME20) has a mixture of 20% JME and 80% diesel. The antioxidant at different concentrations, viz., 500, 1000, 1500, and 2000 ppm, is doped in JME20, and the blends are designated as AL1, AL2, AL3, and AL4, respectively. The test engine is converted to run on the low heat rejection (LHR) mode by coating the piston with a mixture of two different ceramic materials, i.e., yttria-stabilized zirconia and cerium oxide (CeO2), with a thickness of 0.3 mm of the topcoat and 0.15 mm of the bond coat of material NiAl. The emissions, performance, and combustion of the test engine run on antioxidant-doped JME20 fuels in conventional engine operation and LHR mode are evaluated, analyzed, and presented in this paper. Results indicate that, among the four antioxidant-doped JME20 fuels, JME20AL4 gives better performance and lower exhaust emissions. The engine's cylinder pressure and heat release rate are decreased by about 4.7% and 6.4%, respectively, at full load, for JME20 AL4. The delay period and combustion duration of the fuel are improved by about 26.8% and 10.8%, respectively, at maximum load. The NO, HC, and CO emissions are reduced by about 17.3%, 19.3%, and 44.2%, respectively, for JME20 AL4, at maximum load.

Efficiency of the autonomous modular system in the implementation of the spray application process in the vineyard

Autonomous modular system mounted on a conventional (CON) sprayer operating on the principle of pulse-width modulation (PWM) control of electromagnetic valves represents state-of-the-art technology for implementation controlled application of spray mixture without changing the operating parameters of the sprayer (e.g. spray pressure, nozzle size). In accordance with the principles of precision viticulture, the pulse width modulation control is the primary technology, which allows the application of the required amount of spray mixture exclusively to the target areas of the vine without changing the droplet size spectrum and allows for even deposit quality and reducing the drift outside the target areas. In the vineyard, we tested an autonomous axial sprayer prototype throughout the entire spraying season in 2021 on which we have installed an autonomous modular system with enabled pulse-width control. We tested two modes of operation of the sprayer prototype, namely autonomous (continuous duty cycle control (DC: 0 to 100%)) and conventional (nozzle fully open at all time), at a steady spray speed of 6 kmh-1. We compared the amount of PPP expressed as a percentage between autonomous and conventional mode of operation of the sprayer through individual nozzles on the sprayer. The maximum saving of the spray mixture of 69.8%, through an individual nozzle was measured at phenological stage of the vine BBCH 55. A comparative analysis between the CON and PWM mode of the spray mixture application showed that we saved 626.24 l per year in the automated mode of operation.

Quay crane and yard truck dual-cycle scheduling with mixed storage strategy

In order to enhance the efficiency of port operations, the scheduling problem of the quay cranes and yard trucks is crucial. Conventional port operation mode lacks optimization research on efficiency of port handling operation, yard truck scheduling, and container storage location. To make quay crane operations and horizontal transportation more efficient, this study uses a dual-cycle strategy to focus on a quay crane and yard truck scheduling problem in conjunction with a mixed storage strategy. A dispatching plan for yard trucks is considered, as well as the storage location of inbound containers. Based on the above factors, a mixed-integer programming model is formulated to minimize vessels’ berth time for completing all tasks. The proposed model is solved using a particle swarm optimization-based algorithm. Validation of the proposed model and algorithm is conducted through numerical experiments. Additionally, some managerial implications which may be potentially useful for port operators are obtained.

Artificial Intelligence, Blockchain Technology, and Risk-Taking Behavior in the 4.0IR Metaverse Era: Evidence from Bangladesh-Based SMEs

This study investigates the variables affecting the adoption of blockchain technology (BT) among small and medium-sized enterprises (SMEs) with the application of artificial intelligence (AI) via the mediating lens of risk-taking behavior. As an initial sample, 150 owners/top managers from 150 SMEs (one informant from each) in Dhaka, Bangladesh, were chosen. A stratified random sample was employed for this cross-sectional study. Applying structural equation modeling, the combined influence of internal and external variables influencing the intention to adopt BT is explored. Results show that: (1) knowledge of artificial intelligence has a positive and significant effect on the adoption of blockchain technology; (2) the relevant advantage of artificial intelligence has a positive and significant effect on the adoption of blockchain technology; (3) perceived ease of use of artificial intelligence has a positive and significant effect on the adoption of blockchain technology; (4) risk-taking behavior mediates the relationship between knowledge of artificial intelligence and adoption of blockchain technology; (5) risk-taking behavior does not mediate the relationship between relevant advantage and perceived ease of use of artificial intelligence with the adoption of blockchain technology. The current study is one of the few empirical investigations relating to SMEs using artificial intelligence and blockchain technologies for business operations. The study’s limitations are the small sample size and use of a single informant. However, the findings on the adoption of blockchain technology have applications for boosting the competitiveness of SMEs. This study’s originality stems from two factors: the novelty of blockchain technology and its potential to upend SMEs’ conventional mode of operation. It highlights the need to consider the key variables affecting SMEs’ adoption of blockchain technology with artificial intelligence.

Cyclic use of groundwater: An innovative way to improve performance of a groundwater source heat pump system during a cooling period

The building sector is a large user of energy and thus a large emitter of CO2. Replacing traditional energy with renewable energy in buildings can effectively reduce greenhouse gas emissions and global warming effects. This paper introduces a new groundwater source heat pump (GWSHP) system installed for air-conditioning of an official room. The main innovation of the new GWSHP system is the cyclic use of groundwater to save the electricity consumption of the lifting pump that pumps the groundwater from a well and also to reduce the amount of groundwater needed by the GWSHP system. The cyclic use of groundwater was realized by adding a circulating pump and a tank in the GWSHP system and intermittently running the lifting pump according to the water temperature in a groundwater heat exchanger. The performances of the new GWSHP system for four different operation modes of the lifting pump were evaluated and compared based on measurements of representative days in 2017 and 2019. The results show that the cyclic use of groundwater with an optimal operation mode can not only effectively improve the performance of the GWSHP system but also significantly reduce groundwater consumption. Specifically, the coefficient of performance of the GWSHP system was increased from 3.6 for conventional operation mode with no cyclic use of groundwater to 4.3 for the optimal operation mode, and the groundwater consumption per working day was significantly decreased from 9.2 m3 for conventional operation mode to 4.0 m3 for the optimal operation mode. Moreover, the long-term performance for three consecutive years from 2018 to 2020 was also evaluated based on measurements, and the results show that the long-term performance is almost the same as the performance of the representative day, which means that the representative day method used in this paper to evaluate the performance of the GWSHP system is feasible and reliable. The operating experience of this study can provide an important reference for the design and selection of GWSHP systems in areas with a different abundance of groundwater.

Retarding frosting of an air source heat pump by using vapor-bypassed evaporation technique

• Vapor-bypassed evaporation is firstly used to retard frosting for ASHP applications. • A tested ASHP system that contains two operation modes is established. • Frosting characteristics of the two operation modes are investigated in detail. • Vapor-bypassed evaporation is more suitable for high heating capacity conditions. This paper presents a comparative experimental study on the frosting characteristics of an air source heat pump system that contains two operation modes, i.e., the vapor-bypassed evaporation (VB) mode and the conventional operation (CO) mode. For VB mode, a phase separator is installed inside the evaporator refrigerant circuit to bypass vapor refrigerant, which can increase the average evaporation temperature for retarding frosting by reducing refrigerant pressure drop and decreasing the area of refrigerant inferior heat transfer coefficient region (mist flow region). According to the experimental results, under H2 condition (indoor: 20/15 °C; outdoor: 2/1 °C), as the initial refrigerant mass flow rate ranges 35–45 g / s , the VB mode yields 4.30–7.06% lower frost mass, 3.9–7.3% higher average heating capacity and 6.4–10.8% higher coefficient of performance (COP) over CO mode with the frosting duration of 60 min. Moreover, under H3 condition (indoor: 20/15 °C; outdoor: -7/-8 °C), the frosting duration is set as 100 min, and the VB mode obtains 9.67% lower frost mass, 7.0% higher average heating capacity and 13.3% higher COP over CO mode. Generally, the vapor-bypassed evaporation technique has a great application potential in retarding frosting and improving performance of an air source heat pump system especially under high heating capacity or low ambient temperature conditions.

High-Sensitivity Glycan Profiling of Blood-Derived Immunoglobulin G, Plasma, and Extracellular Vesicle Isolates with Capillary Zone Electrophoresis-Mass Spectrometry

We developed a highly sensitive method for profiling of N-glycans released from proteins based on capillary zone electrophoresis coupled to electrospray ionization mass spectrometry (CZE-ESI-MS) and applied the technique to glycan analysis of plasma and blood-derived isolates. The combination of dopant-enriched nitrogen (DEN)-gas introduced into the nanoelectrospray microenvironment with optimized ionization, desolvation, and CZE-MS conditions improved the detection sensitivity up to ∼100-fold, as directly compared to the conventional mode of instrument operation through peak intensity measurements. Analyses without supplemental pressure increased the resolution ∼7-fold in the separation of closely related and isobaric glycans. The developed method was evaluated for qualitative and quantitative glycan profiling of three types of blood isolates: plasma, total serum immunoglobulin G (IgG), and total plasma extracellular vesicles (EVs). The comparative glycan analysis of IgG and EV isolates and total plasma was conducted for the first time and resulted in detection of >200, >400, and >500 N-glycans for injected sample amounts equivalent to <500 nL of blood. Structural CZE-MS2 analysis resulted in the identification of highly diverse glycans, assignment of α-2,6-linked sialic acids, and differentiation of positional isomers. Unmatched depth of N-glycan profiling was achieved compared to previously reported methods for the analysis of minute amounts of similar complexity blood isolates.

Cipher Block Chaining Support Vector Machine for Secured Decentralized Cloud Enabled Intelligent IoT Architecture

The growth of internet era leads to a major transformation in a storage of data and accessing the applications. One such new trend that promises the endurance is the Cloud computing. Computing resources offered by the Cloud includes the servers, networks, storage, and applications, all as services. With the advent of Cloud, a single application is delivered as a metered service to numerous users, via an Application Programming Interface (API) accessible over the network. The services offered via the Cloud are such as the infrastructure, software, platform, database and web services. The main motivation of this application model is to provide computationally secure key generation to protect the data via encryption. This key generation in the cryptography process falls into three categories in this research work. In the first part, SVM based encryption service model is constructed for which the key generation is from the conventional encryption operation mode with some improvements. To make the process more complex, the optimization techniques are taken into account for the key generation in descendant two methods application model that acts computationally more secure specifically for Cloud environment. The results of security analysis confirm the effectiveness of the proposed application model withstands potentially against various attacks such as Chosen Cipher Attack, Chosen Plain text Attack indistinguishable attacks for files. In case of images, it resists well against statistical and differential attacks. Comparative Analysis shows evidence of the efficiency of the developed pioneering application model quality and strength compared with that of the existing services.

Simulation study on the performance of a vapor-bypassed evaporator for heat pump applications

• A mathematical model for the vapor-bypassed evaporator is developed. • Corresponding experiments were conducted to validate the model accuracy. • Entropy generation is applied to evaluate the evaporator overall performance. • Phase separation position and channel number of the evaporator are optimized. This paper presents a simulation study on the vapor-bypassed evaporator for heat pump applications. The vapor-bypassed evaporator, in which a phase separator is set in the middle of the refrigerant circuit to bypass vapor refrigerant, can reduce the refrigerant pressure drop for enhancing the evaporator overall performance. A mathematical model for the vapor-bypassed evaporator is developed and the experiments were conducted to validate its accuracy. Based on the entropy generation minimization theory, the optimum phase separation positions and refrigerant channel numbers of the evaporator for various operation conditions are selected out. According to the simulation results, as the required heat transfer capacity ranges 4~10 kW, the vapor-bypassed (VB) mode obtains 25.6~84.6 kPa lower refrigerant pressure drop and 3.1~25.3% lower entropy generation than the conventional operation (CO) mode. Moreover, when the ambient temperature ranges 5~15°C, the entropy generation of VB mode is decrease by 22.3~11.5% than CO mode. In general, applying the vapor-bypassed technique is a promising way for improving the evaporator performance especially under high heat transfer capacity and low ambient temperature conditions.

Performance improvement strategy for photovoltaic generation through dynamic reconfiguration of cell strings

In this paper, a strategy for the dynamic reconfiguration of photovoltaic (PV) strings and inverters is proposed to improve the PV system efficiency and reduce the harmonic emissions of the PV system under low irradiance conditions. In the proposed PV group control system, parallel-bridge switches are controlled to form multi-PV groups that can run jointly with multi-inverters. The benefit and harmonic current of the group control system are used to define the performance index. The dynamic reconfiguration strategy is used to control the connection mode of the PV system to optimize the index. The fluctuation of the PV string output power on the time scale is considered, the PV power variation range is predicted based on the least squares regression algorithm, the connection modes of the PV system are evaluated to prevent inverter overload, and the optimal connection mode is decided when the system frequently switches based on the voting theory method. An experimental system platform comprising three PV array simulators and three inverters is designed, and several scenarios of PV system operation are constructed to verify the feasibility and effectiveness of the proposed strategy. Experimental results show that compared with the conventional PV operation mode, the proposed strategy can improve PV generation performance under low solar irradiation. Based on the benefits of the control strategy, the scheme cost and recovery time are evaluated, and investors can quickly recover costs.

Performance analysis of HCCI engine powered by tamanu methyl ester with various inlet air temperature and exhaust gas recirculation ratios

The extensive usage of petroleum as a fuel in a conventional engine produces harmful pollutants and also leads to global warming. CI engines have certain advantages over SI engines such that they have higher efficiency and emit lesser CO and HC, but they also have disadvantages such as high smoke and NOx. A homogeneous charge compression ignition engine (HCCI) is a better solution to minimize smoke and NOx simultaneously. The present study was performed comparing the conventional CI engine and HCCI mode of operation fueled with tamanu methyl ester (TME). The HCCI engine was run at various inlet air temperatures (IAT) (80 °C, 90 °C, and 100 °C) because tamanu methyl ester cannot be vaporized at room temperature. The results exhibited that TME operated CI engine noticed higher brake thermal efficiency (BTE) and fuel economy and also lesser carbon monoxide (CO) and unburned hydrocarbon (UBHC) emission than the HCCI engine. HCCI engine with enhanced IAT showed lower NOx and smoke emission than conventional engine. From the results, the optimum IAT was found to be 90 °C, so further experiments were carried out using the IAT 90 °C at various exhaust gas recirculation (EGR) ratios. The EGR associated HCCI engine produces ultra-lean NOx emission, but on the other hand, it shows slightly lower BTE, cylinder pressure and heat release rate than the engine operating without EGR. The results also exhibited that elevation of IAT beyond 100 °C leads to short HCCI combustion, tending to knock, thus leading to unstable operation.

Continuous adsorption in food industry: The recovery of sinapic acid from rapeseed meal extract

Efficient recovery and utilization of valuable components from industrial food side streams is a main driver towards a circular economy. Among different available purification techniques, adsorption can effectively recover these components. However, the conventional batch mode of operation can limit its applicability in food processes due to limited efficiency. This work compares conventional batch packed bed adsorption with semi-continuous adsorption (so-called CaptureSMB) for the recovery of sinapic acid at industrial scale, using a food grade resin AmberliteTM FPX66. A mathematical mechanistic model able to describe semi-continuous operation is successfully validated and used to identify optimum operating parameters to maximize productivity and resin capacity utilization in batch and semi-continuous operating modes. The results indicate that CaptureSMB outperforms batch operation, increasing productivity from 5.18 g/L/h to 10.3 g/L/h for a given yield (>97%). A resin capacity utilization (RU) of around 70% is observed in both operating modes when productivity is maximized. A 92% RU can be accomplished for a given yield using the CaptureSMB process at a productivity of 7.0 g/L/h, higher than for conventional batch operation. The use of semi-continuous adsorption operation in food industry contributes to more efficient processes at reduced purification costs.

An optimal three fractions yielding simulated moving bed chromatographic separation: Triple switch SMBC

Among the various degrees of freedom Simulated moving bed chromatography possesses, the current work deals with manipulation of operating conditions comprising internal flow rates and switching period. The conventional mode of operation yields a single fraction of the extract and raffinate with a single set of operating conditions whereas the current work proposes a novel triple switch mode of operation which is characterised by three sets of internal flow rates and switching period and yields three fractions. Under optimal conditions, the higher degrees of freedom have the potential of yielding higher extract purities than conventional as well as dual switch modes of operation with two sets of operating conditions. A multi-objective optimisation problem has been solved which maximizes the purity of one of the three extract fractions, for a certain minimum extract recovery and minimum feed flow rate. It is through a lower purity in two of the three fractions that a superior extract purity is achieved. This finding has been corroborated by a modeling based study on the linear adsorption isotherm based separation of fructose-glucose in deionised water on a cation exchange resin.

Combined velocity and position control of large inertial hydraulic swing mechanism considering energy balance of supply and demand

Abstract The position of a conventional large inertial hydraulic swing system is controlled by the operator-in-loop, the production efficiency of which is poor, and the repetitive positioning precision is low owing to slow human reactions. To address this problem, this study proposes a combined velocity and position control strategy based on the independent metering control system. In this method, it is not necessary to change the conventional operation mode. If the required rotary angle is the same in each swing process, a precise desired position is provided as the input signal for closed-loop position control. If the required rotary angle is random, in order to be compatible with the handle operation mode used in mobile machines, a handle signal integral control method is proposed. Moreover, velocity feedback is used to improve the control accuracy, while differential pressure feedback is used to reduce the position overshoot. Meanwhile, to improve the system dynamic characteristics during the braking process, an energy balance principle is applied. The proposed strategy is verified with simulation and a 6 t hydraulic excavator. The simulation and experimental results demonstrate that a higher positioning accuracy can be achieved with different desired angular displacements. Furthermore, the position overshoot, and velocity and pressure fluctuation are avoided, while the dynamic characteristics are clearly improved.