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Showing records 34843 to 34867 of 43292. [First] Page: 1 1391 1392 1393 1394 1395 1396 1397 1398 1399 Last
34843. LAPSE:2023.4290
MicroRNAs Encoded by Virus and Small RNAs Encoded by Bacteria Associated with Oncogenic Processes
February 22, 2023 (v1)
Subject: Biosystems
Keywords: bacteria, microRNA, oncogenesis, small RNAs, viruses
Cancer is a deadly disease and, globally, represents the second leading cause of death in the world. Although it is a disease where several factors can help its development, virus induced infections have been associated with different types of neoplasms. However, in bacterial infections, their participation is not known for certain. Among the proposed approaches to oncogenesis risks in different infections are microRNAs (miRNAs). These are small molecules composed of RNA with a length of 22 nucleotides capable of regulating gene expression by directing protein complexes that suppress the untranslated region of mRNA. These miRNAs and other recently described, such as small RNAs (sRNAs), are deregulated in the development of cancer, becoming promising biomarkers. Thus, resulting in a study possibility, searching for new tools with diagnostic and therapeutic approaches to multiple oncological diseases, as miRNAs and sRNAs are main players of gene expression and host−infectious agent inter... [more]
34844. LAPSE:2023.4289
Value Configurations for Data and Connectivity Solutions in Digitalized Future Factories
February 22, 2023 (v1)
Subject: Environment
Keywords: 5G, business ecosystem, digitalization, future factories, Industry 4.0, local operator, value configuration
The ongoing Industry 4.0 transformation places significant pressures on how businesses create and capture value. Technological advancements such as next-generation mobile communications are reshaping the business ecosystem of Industry 4.0, resulting in emerging business opportunities for new players, such as local operators, to collaborate and compete with mobile communications companies that are implementing I4.0. These changes raise the need to explore emerging business opportunities concerning the digitalization of future factories. New data and connectivity services are introduced to serve the needs of rapidly increasing machine-type communications that rely on connectivity, primarily through the fifth generation (5G) mobile solutions provided by local operators. Thus, this paper outlines the potential value configurations for data and connectivity solutions by identifying, matching, and bridging the utilizable resources and addressable needs within the factory processes. The resea... [more]
34845. LAPSE:2023.4288
Analysis of the Dispersion of Viscoelastic Clusters in the Industrial Rotor-Stator Equipment
February 22, 2023 (v1)
Subject: Modelling and Simulations
Keywords: Computational Fluid Dynamics, rheology, rotor-stator mixer, shear modulus, viscoelasticity
Materials with complex rheology and viscoelasticity may require special equipment for processing, such as for dispergation. Rheological and mechanical data of the material can help with finding the required equipment or designing equipment. For highly viscous and complex material, a rotor-stator mixer can be a good choice for dispergation. Due to the laminar or creeping mechanism of flow inside the equipment, the dispergation mechanism is assumed to be a combination of the shear stress and slicing of the material by the rotor and stator blades. For the validation of the theory, the mechanical properties of the viscose identified in a previous work were used for comparison with the data from the CFD simulation of the rotor-stator mixer. The comparison showed that the rotor-stator device can overcome the complex shear modulus and ultimate strength of the material and homogenize the solution through a combination of the shear stress and slicing. The theory was also confirmed on the proces... [more]
34846. LAPSE:2023.4287
Evaluation of the Potential of Agro-Industrial Waste-Based Composts to Control Botrytis Gray Mold and Soilborne Fungal Diseases in Lettuce
February 22, 2023 (v1)
Subject: Process Control
Keywords: agro-industrial wastes, biological control, Botrytis cinerea, disease severity and incidence, disease suppressive soils, lignocellulosic composts, macrodilution assay, soilborne pathogens
Composts are widely used in horticulture as organic amendments to improve the properties of soils. Composts have also been reported to enhance the disease suppressive potential of soils and, therefore, could be used as a strategy for managing plant diseases. The aim of this study was to test the ability of soils amended with four different agro-industrial waste-based composts (chestnut peels and shells, spent coffee grounds, grape marc, and olive leaves) to inhibit the growth and activity of Botrytis cinerea and several soilborne pathogens. First, the capacity of aqueous compost extracts to inhibit the growth of Botrytis cinerea and five soilborne fungi was evaluated in vitro using a broth macrodilution method. Second, lettuce plants were grown on soils amended with composts and inoculated either with B. cinerea or the soilborne fungus Fusarium oxysporum Schlechtendahl isolated from lamb’s lettuce. The determination of minimal inhibitory concentrations indicated that none of the compos... [more]
34847. LAPSE:2023.4286
Characterization of Novel Solid Dispersions of Moringa oleifera Leaf Powder Using Thermo-Analytical Techniques
February 22, 2023 (v1)
Subject: Food & Agricultural Processes
Keywords: food technology, FTIR, Moringa oleifera leaf powder, polyethylene glycol, solid dispersion, TGA
leaf powder (MOLP) has been identified as the most important functional ingredient owing to its rich nutritional profile and healthy effects. The solubility and functional properties of this ingredient can be enhanced through solid dispersion technology. This study aimed to investigate the effects of polyethylene glycols (PEGs) 4000 and 6000 as hydrophilic carriers and solid dispersion techniques (freeze-drying, melting, solvent evaporation, and microwave irradiation) on the crystallinity and thermal stability of solid-dispersed Moringa oleifera leaf powders (SDMOLPs). SDMOLPs were dully characterized using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The PXRD results revealed that the solid dispersions were partially amorphous with strong diffraction peaks at 2θ values of 19° and 23°. The calorimetric and thermogravimetric curves showed that PEGs conferred greater stabil... [more]
34848. LAPSE:2023.4285
The Role of Selected Chemokines in the Peritoneal Fluid of Women with Endometriosis—Participation in the Pathogenesis of the Disease
February 22, 2023 (v1)
Subject: Numerical Methods and Statistics
Keywords: chemokines, endometriosis, inflammation, peritoneal fluid
Endometriosis is a disorder characterized by the presence of endometrial tissue outside the uterine cavity, primarily into the peritoneal cavity. It is known as a complex, chronic inflammatory disease and it is strongly associated with immune dysregulation. Various soluble mediators of the immune and inflammatory responses, including chemokines, play an important role in these processes. The aim of the study was to understand the role of the chemokines MCP-1, MCP-2, MCP-3, MCP-4, MIP-1 α, MIP-1β, eotaxin 2, eotaxin 3, ENA-78, and fractalkine in the development of endometriosis through their assessment in the peritoneal fluid of women with endometriosis. The study group included 58 women with endometriosis who were diagnosed during laparoscopy and then confirmed by histopathology. In 15 women from the reference group, laparoscopic examination demonstrated a normal status of the pelvic organs without any evidence of endometriosis nor inflammation in the peritoneal cavity. The peritoneal... [more]
34849. LAPSE:2023.4284
Industrial Symbiosis for Optimal Bio-Waste Management and Production of a Higher Value-Added Product
February 22, 2023 (v1)
Subject: Environment
Keywords: animal by-products, catering, compost quality parameters, hospitality, industrial symbiosis, intensive composting, life cycle assessment, life cycle inventory
A considerable amount of food waste ends up in centralized treatment plants due to the lack of preventive measures, resulting in significant environmental impacts. Hospitality food waste management is even more resource-intensive because of animal by-products regulation. According to this regulation, companies must store and then consign waste to specific waste managers. The extensive need for transportation of high-moisture-content materials is the leading cause of the impact. Moreover, the management of category III animal by-products is costly for companies. A previous study has shown the economic benefits of decentralized animal by-product treatment by intensive composting in catering companies. Although the produced compost was characterized by exceptional quality parameters, it was phytotoxic. The investigation of hospitality waste management is scarcely discussed among scholars, and waste management on a regional scale is nearly absent. This study examines the regional managemen... [more]
34850. LAPSE:2023.4283
Application of Green Technology in Gelatin Extraction: A Review
February 22, 2023 (v1)
Subject: Environment
Keywords: high-pressure processing, microwave extraction, novel technology, subcritical water extraction, ultrasound extraction
Growing demands for green and sustainable processing that eliminates the utilization of toxic chemicals and increases efficiency has encouraged the application of novel extraction technologies for the food industry. This review discusses the principles and potential application of several green technology for gelatin extraction. Several novel technologies and their processing efficiency are discussed in this review. Furthermore, factors that affect the quality of the gelatin produced from different sources are also highlighted. The potential application of ultrasound-assisted extraction (UAE), subcritical water extraction, high-pressure processing, and microwave-assisted extraction (MAE) to improve gelatin extraction are addressed. These technologies have the potential to become an efficient extraction method compared to the conventional extraction technologies. Several combinations of green and conventional technologies have been reported to yield promising results. These combinations... [more]
34851. LAPSE:2023.4282
Moving Multiscale Modelling to the Edge: Benchmarking and Load Optimization for Cellular Automata on Low Power Microcomputers
February 22, 2023 (v1)
Subject: Modelling and Simulations
Keywords: Cellular Automata, distributed computing, edge computing, NVidia Jetson, RaspberryPi
Numerical computations are usually associated with the High Performance Computing. Nevertheless, both industry and science tend to involve devices with lower power in computations. This is especially true when the data collecting devices are able to partially process them at place, thus increasing the system reliability. This paradigm is known as Edge Computing. In this paper, we propose the use of devices at the edge, with lower computing power, for multi-scale modelling calculations. A system was created, consisting of a high-power device—a two-processor workstation, 8 RaspberryPi 4B microcomputers and 8 NVidia Jetson Nano units, equipped with GPU processor. As a part of this research, benchmarking was performed, on the basis of which the computational capabilities of the devices were classified. Two parameters were considered: the number and performance of computing units (CPUs and GPUs) and the energy consumption of the loaded machines. Then, using the calculated weak scalability a... [more]
34852. LAPSE:2023.4281
Production Calculation Model of Thermal Recovery after Hydraulic Fracturing and Packing in Tight Reservoir
February 22, 2023 (v1)
Subject: Energy Systems
Keywords: fracturing, heat loss, heavy oil production, thermal oil recovery, tight oil reservoir
It was deemed important to calculate the thermal recovery production model of tight oil reservoirs after fracturing and packing based on the field data of an oilfield in Bohai Sea, China. The thermal recovery production of a tight oil reservoir after fracturing is demonstrated through theoretical calculation and practical field data on the premise of five hypotheses. Fractures change the fluid flow capacity of the reservoir. Combined with the relevant theories of reservoir thermal production, the dual porosity system in the fractured zone and the single porosity system in the unfractured zone were established. The calculation models of heat loss in the fractured and unfractured zones were derived to determine the thermal recovery heating radius of the reservoir after fracturing and packing. Combined with the pseudo-steady state productivity formula of the composite reservoir, a production calculation model of thermal recovery after fracturing and packing in the tight oil reservoir was... [more]
34853. LAPSE:2023.4280
Digital Twins for Wind Energy Conversion Systems: A Literature Review of Potential Modelling Techniques Focused on Model Fidelity and Computational Load
February 22, 2023 (v1)
Subject: Modelling and Simulations
Keywords: digital twins, direct-drive, Industry 4.0, permanent magnet synchronous generator, wind energy, wind turbines
The Industry 4.0 concept of a Digital Twin will bring many advantages for wind energy conversion systems, e.g., in condition monitoring, predictive maintenance and the optimisation of control or design parameters. A virtual replica is at the heart of a digital twin. To construct a virtual replica, appropriate modelling techniques must be selected for the turbine components. These models must be chosen with the intended use case of the digital twin in mind, finding a proper balance between the model fidelity and computational load. This review article presents an overview of the recent literature on modelling techniques for turbine aerodynamics, structure and drivetrain mechanics, the permanent magnet synchronous generator, the power electronic converter and the pitch and yaw systems. For each component, a balanced overview is given of models with varying model fidelity and computational load, ranging from simplified lumped parameter models to advanced numerical Finite Element Method (F... [more]
34854. LAPSE:2023.4279
An ATM/CHK2 Signaling Pathway Induces Nuclear Translocation of SRPK2 in Cisplatin-Treated HeLa Cells
February 22, 2023 (v1)
Subject: Biosystems
Keywords: ATM, Chk2, cisplatin, drug resistance, SR protein kinases, SRPK2
Chemotherapeutic agents are frequently used to treat various cancers, but the mechanisms mediating the cellular response to the drugs are still not fully understood. We previously reported that the nuclear translocation of serine/arginine protein kinases (SRPKs), triggered by the exposure of cells to DNA damage-inducers, plays a pivotal role in drug responsiveness. Here, we investigated the mechanism linking the nuclear accumulation of SRPK2 to the cisplatin treatment of HeLa cells. We present experimental evidence that nuclear SRPK2 acts downstream of Chk2 in the ATM/Chk2 cascade. The inhibition of ATM or Chk2 kinase activity by specific low-molecular-weight inhibitors restricted SRPK2 to the cytoplasm and conferred tolerance to cisplatin treatment. A similar effect was achieved by treating cells with SRPIN340, a selective SRPK1/2 inhibitor, thus confirming previous findings that kinase activity is indispensable for the nuclear import of SRPKs. These data add to previous findings that... [more]
34855. LAPSE:2023.4278
In Silico Analysis and Experimental Evaluation of Ester Prodrugs of Ketoprofen for Oral Delivery: With a View to Reduce Toxicity
February 22, 2023 (v1)
Subject: Numerical Methods and Statistics
Keywords: gastric irritation, hepatotoxicity, ketoprofen, prodrug, ProTox-II, SwissADME
The present research aimed to synthesize ketoprofen prodrugs and to demonstrate their potentiality for oral treatment to treat chronic inflammation by reducing its hepatotoxicity and gastrointestinal irritation. Methyl 2-(3-benzoyl phenyl) propanoate, ethyl 2-(3-benzoyl phenyl) propanoate and propyl 2-(3-benzoyl phenyl) propanoate was synthesized by esterification and identified by nuclear magnetic resonance (1HNMR) and infrared (IR) spectrometric analysis. In silico SwissADME and ProTox-II analysis stated methyl derivative as ideal candidate for oral absorption, having a >30-fold LD50 value compared to ketoprofen with no hepatotoxicity. Moreover, in vivo hepatotoxicity study demonstrates that these ester prodrugs have significantly lower effects on liver toxicity compared to pure ketoprofen. Furthermore, ex vivo intestinal permeation enhancement ratio was statistically significant (* p < 0.05) compared to ketoprofen. Likewise, the prodrugs were found to exhibit not only remarkable... [more]
34856. LAPSE:2023.4277
Effect of Different Configurations on Bubble Cutting and Process Intensification in a Micro-Structured Jet Bubble Column Using Digital Image Analysis
February 22, 2023 (v1)
Subject: Energy Systems
Keywords: bubble cutting, bubble size distribution, chemical reaction engineering, mass transfer, micro-structured jet bubble column, Process Intensification
An experimental study was conducted in this work to investigate the effect of different configurations on bubble cutting and process intensification in a micro-structured jet bubble column (MSJBC). Hydrodynamic parameters, including bubble size, flow field, liquid velocity, gas holdup as well as the interfacial area, were compared and researched for a MSJBC with and without mesh. The bubble dynamics and cutting images were recorded by a non-invasive optical measurement. An advanced particle image velocimetry technique (digital image analysis) was used to investigate the influence of different configurations on the surrounding flow field and liquid velocity. When there was a single mesh and two stages of mesh compared with no mesh, the experimental results showed that the bubble size decreased by 22.7% and 29.7%, the gas holdup increased by 5.7% and 9.7%, and the interfacial area increased by more than 34.8% and 43.5%, respectively. Significant changes in the flow field distribution cau... [more]
34857. LAPSE:2023.4276
Special Issue on “Dynamic Modeling and Control in Chemical and Energy Processes”
February 22, 2023 (v1)
Subject: Modelling and Simulations
Recent energy policies have enforced the need to minimize GHG emissions [...]
34858. LAPSE:2023.4275
Differentially Expressed Genes Correlated with Fibrosis in a Rat Model of Chronic Partial Bladder Outlet Obstruction
February 22, 2023 (v1)
Subject: Process Control
Keywords: chronic partial bladder outlet obstruction, fibrosis, microarray, Tgfb, Thbs1
Chronic partial bladder outlet obstruction (PBOO) is a prevalent clinical problem that may result from multiple etiologies. PBOO may be a secondary condition to various anatomical and functional abnormalities. Bladder fibrosis is the worst outcome of PBOO. However, gene alterations and the mechanism of fibrosis development after PBOO onset are not clear. Therefore, we aimed to investigate gene expression alterations during chronic PBOO. A rat model of PBOO was established and validated by a significant increase in rat bladder weight. The bladder samples were further analyzed by microarray, and differentially expressed genes (DEGs) that are more related to PBOO compared with the control genes were selected. The data showed that 16 significantly upregulated mRNAs and 3 significantly downregulated mRNAs are involved in fibrosis. Moreover, 13 significantly upregulated mRNAs and 12 significantly downregulated mRNAs are related to TGFB signaling. Twenty-two significantly upregulated mRNAs an... [more]
34859. LAPSE:2023.4274
Effects of Seasonal Thermal Stratification on Ammonia Nitrogen Transformation in a Source Water Reservoir
February 22, 2023 (v1)
Subject: Environment
Keywords: ammonia nitrogen, sediments, source water reservoir, thermal stratification
Seasonal thermal stratification has a significant impact on water quality. In this paper, the variation of vertical distribution of ammonia nitrogen in a source water reservoir was studied, on the base of field monitoring data. The dominant factor of the variation in ammonia nitrogen is the anaerobic environment caused by the seasonal thermal stratification, which leads to the degradation of nitrogen-containing organic compounds in the sediments. To determine the rates of ammonia accumulation, an in situ experimental chamber was used. The results showed that, before the formation of thermal stratification in the reservoir, sediments in the bottom of the water have a high tendency to release ammonia; the rates of ammonia accumulation in the overlying water are 40.31−111.41 mg·m−2·d−1. However, thermal stratification causes changes in the physical and chemical properties of the sediment and reduction in the degradability of the nitrogen-containing compound in the sediment. The rates of a... [more]
34860. LAPSE:2023.4273
Overview of Vehicle Exhaust Particle Number Regulations
February 22, 2023 (v1)
Subject: Environment
Keywords: air pollution, catalytic stripper, emission regulations, Particle Measurement Programme (PMP), particle number, particulate matter, portable emissions measurement system (PEMS), real-driving emissions (RDE), vehicle exhaust emissions
Vehicle emissions are a significant source of air pollution in cities. Particulate matter (PM) is a pollutant with adverse health effects. Regulations worldwide determine the PM exhaust emissions of vehicles by gravimetric quantification of the mass deposited on a filter over a test cycle. The introduction of particulate filters as vehicle exhaust gas aftertreatment devices led to low PM emissions. A particle number methodology (counting solid particles > 23 nm), complementary to the PM mass measurement, was developed by the PMP (Particle Measurement Programme) group of the GRPE (Working Party on Pollution and Energy) of the UNECE (United Nations Economic Commission for Europe) during the first decade of the 21st century. The methodology was then introduced in the EU (European Union) regulations for light-duty (2011), heavy-duty (2013), and non-road mobile machinery (2019). In parallel, during the last 15 years, UN (United Nations) regulations and GTRs (Global Technical Regulations) in... [more]
34861. LAPSE:2023.4272
Incompatible Deformation Model of Rocks with Defects around a Thick-Walled Cylinder
February 22, 2023 (v1)
Subject: Energy Systems
Keywords: finite element, incompatibility, plastic deformation, rock
Before the excavation of underground engineering, joints, fissures, and voids already exist in the rock—that is, there are defects in the rock. Due to the existence of these defects, the rock produces plastic deformation, which can lead to incompatible deformation. Therefore, the classic continuum theory cannot accurately describe the deformation of the rock. In this paper, a relationship between the strain tensor and metric tensor was studied by analyzing the three states of elastic plastic deformation, and the elasto-plastic incompatible model was built. Additionally, the stress and deformation of a thick-walled cylinder under hydrostatic pressure was investigated by using a finite element program written in the FORTRAN language. The results show that the plastic strain is associated with not only deviator stress but also the distribution of defects (represented by the incompatible parameter R). With the value of R increasing, the defects in the rock increased, but the elastic plasti... [more]
34862. LAPSE:2023.4271
Reliability Study of Parameter Uncertainty Based on Time-Varying Failure Rates with an Application to Subsea Oil and Gas Production Emergency Shutdown Systems
February 22, 2023 (v1)
Subject: Energy Systems
Keywords: failure rate, model modification, parameter uncertainty, reliability evaluation, subsea emergency shutdown system, time-varying
The failure rate of equipment during long-term operation in severe environment is time-varying. Most studies regard the failure rate as a constant, ignoring the reliability evaluation error caused by the constant. While studying failure data that are few and easily missing, it is common to focus only on the uncertainty of reliability index rather than parameter of failure rate. In this study, a new time-varying failure rate model containing time-varying scale factor is established, and a statistical-fuzzy model of failure rate cumulated parameter is established by using statistical and fuzzy knowledge, which is used to modify the time-varying failure rate model. Subsequently, the theorem of the upper boundary existence for the failure rate region is proposed and proved to provide the failure rate cumulated parameter when the failure rate changes the fastest. The proposed model and theorem are applied to analyze the reliability of subsea emergency shutdown system in the marine environme... [more]
34863. LAPSE:2023.4270
A Novel Photovoltaic Module Quick Regulate MPPT Algorithm for Uniform Irradiation and Partial Shading Conditions
February 22, 2023 (v1)
Subject: Energy Systems
Keywords: maximum power point tracking, partial shading conditions, photovoltaic module, uniform irradiation conditions
This study proposed a new photovoltaic module quick regulate (PVM-QR) maximum power point tracking (MPPT) algorithm, which can eliminate the disturbance problem of the hill-climbing (HC) algorithm, especially under low irradiance level and partial shading conditions (PSC). This proposed algorithm has the advantage that it only uses the detection photovoltaic module (PVM) impedance and the open-circuit voltage to simply and quickly calculate the PVM temperature, the irradiance level, and then the key factor parameter u. To achieve the MPPT quickly and accurately, this proposed algorithm is developed for the prediction of the best MPPT duty cycle based on the irradiance level, parameter u, and load. This study verified the proposed MPPT by the measurement results, where the HC algorithm MPPT has 95% efficiency at 0.55 kW/m2 but diverges at 0.2 kW/m2 under uniform irradiation conditions (UIC), and the proposed MPPT algorithm has an improved efficiency (99%) under the same conditions. More... [more]
34864. LAPSE:2023.4269
Adaptive Fuzzy Sliding Mode Control of Omnidirectional Mobile Robots with Prescribed Performance
February 22, 2023 (v1)
Subject: Process Control
Keywords: adaptive fuzzy, composite algorithm, omnidirectional mobile robot, sliding-mode, smooth switching
Adaptive fuzzy sliding-mode control design for omnidirectional mobile robots with prescribed performance is presented in this work. First, an error transformation which transforms the constrained variable into an unconstrained one is carried out. Next, a fuzzy logic system (FLS) for approximating the unknown dynamics is constructed. Based on such a model, a nominal adaptive linearizing controller incorporating a serial-parallel model (SPM)-based composite algorithm, which improves the tracking performance of the overall closed-loop system, is synthesized. To solve the so-called “loss of controllability” problem, a smooth-switching algorithm is embedded which hands over the control authority to an auxiliary sliding-mode controller until the danger is safely bypassed. The proposed design ensures the semi-globally uniformly ultimately bounded stability of the closed-loop signals. Simulation works demonstrating the validity of the proposed design are presented in the final.
34865. LAPSE:2023.4268
Optimization of Microwave-Assisted Extraction of Polyphenols from Lemon Myrtle: Comparison of Modern and Conventional Extraction Techniques Based on Bioactivity and Total Polyphenols in Dry Extracts
February 22, 2023 (v1)
Subject: Biosystems
Keywords: antibacterial, antioxidant, lemon myrtle, MAE, method comparison, Optimization, polyphenols
The aromatic herb lemon myrtle is a good source of polyphenols, with high antioxidant and antimicrobial capacity. In this study, the green extraction technique microwave-assisted extraction (MAE) was applied and the extraction parameters were optimized using response surface methodology (RSM) to maximize the extraction yield of phenolic compound and antioxidant properties. Then, it was compared with other popular novel and conventional extraction techniques including ultrasound-assisted extraction (UAE) and shaking water bath (SWB) to identify the most effective technique for extraction of phenolic compounds from lemon myrtle. The results showed that the MAE parameters including radiation time, power, and sample to solvent ratio had a significant influence on the extraction yield of phenolic compounds and antioxidant capacity. The optimal MAE conditions were radiation time of 6 min, microwave power of 630 W, and sample to solvent ratio of 6 g/100 mL. Under optimal conditions, MAE dry e... [more]
34866. LAPSE:2023.4267
Oscillating Combustion—Primary Measure to Reduce Nitrogen Oxide in a Grate Furnace−Experiments and Simulations
February 22, 2023 (v1)
Subject: Modelling and Simulations
Keywords: CFD-simulation, combustion, grate furnace, oscillation, reduction of NOx
The emission from industries and the mobility sector is under strong legal regulations in many countries worldwide. In Germany, the amendment to the 17th BlmSchV (Federal pollution control ordinance), which has been in force for waste incineration plants since 2013, has given rise to a new limit for nitrogen oxides of 150 mg/m3 as the daily mean level from 2019 on. A similar focus is on biomass-fired plants. According to the MCP (medium combustion plant) guideline of the EU, as a consequence, existing plants are required to either increase their consumption of ammonia water for nitrogen oxide reduction (SNCR process) or back fit SCR catalysts as secondary measures, which is a costly procedure. This paper presents a novel two-stage process in which an oscillating supply of secondary air allows nitrogen oxides to be reduced by approx. 50% at a good burnout level, which may obviate the need for secondary measures. Besides experimental investigations in a fixed bed reactor, CFD simulations... [more]
34867. LAPSE:2023.4266
Position Output Adaptive Backstepping Control of Electro-Hydraulic Servo Closed-Pump Control System
February 22, 2023 (v1)
Subject: Process Control
Keywords: adaptive backstepping control, backstepping, position control, pump-control system
A nonlinear adaptive backstepping control method was proposed to address the system parameter uncertainty problem in the position control process of an electro-hydraulic servo closed-pump control system. This control strategy fully considers the parameter uncertainty of the nonlinear system and establishes the adaptive rate of the uncertain parameter to adjust the parameter disturbance online in real time, thereby improving the accuracy and robustness of the control system. A pump control system experiment platform was used to verify the feasibility of the controller. The experimental results showed that the proposed control strategy provided a good control effect. The pump control system can be controlled with high precision, with a steady-state control accuracy of ±0.02 mm, which serves as a good foundation for the engineering application and promotion of the pump control system.
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