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Editorial for Special Issue on “Intelligent Technologies and Processes for Advanced Nuclear Power and Energy Engineering”
Amir M. Fathollahi-Fard, Vigen H. Arakelian, Zhiwu Li, Zixian Zhang, Guangdong Tian.
February 27, 2023 (v1)
This Special Issue, entitled “Intelligent Technologies and Processes for Advanced Nuclear Power and Energy Engineering”, was organized by the journal Processes as a way to collect original research articles on the latest developments in intelligent technologies and processes for advanced nuclear power and energy systems [...]
Analysis of Fluid Flow in a Radial Centrifugal Pump
Jan Černý, Martin Polák.
February 27, 2023 (v1)
Keywords: ANSYS, centrifugal pump, Particle Image Velocimetry (PIV), performance characteristic
The paper presents a validation of the results of a numerical model of radial centrifugal pump flow using a PIV (Particle Image Velocimetry) experimental method. For this purpose, a 3D model of the pump was created in Inventor, which was then used to design a numerical flow model in Ansys in the CFX module. The performance characteristics of the same pump were measured on an experimental test circuit, and vector maps of the flow in the suction pipe were obtained using the PIV method. The results of the experiment—vector fields of fluid velocity distribution in a suction pipe—were then compared with the outputs of the numerical Ansys model, namely the streamlines and pressure distributions. This comparison demonstrated that the numerical model is most consistent with reality if the input variables are the pressure in front of the pump and the mass flow behind the pump. In this case, the model can determine the pressure at the pump inlet with a deviation of 1% to 10% and create streamlin... [more]
Intensification of endo-1,4-Xylanase Extraction by Coupling Microextractors and Aqueous Two-Phase System
Marko Božinović, Renata Vičević, Nikolina Zekić, Anita Šalić, Ana Jurinjak Tušek, Bruno Zelić.
February 27, 2023 (v1)
Subject: Optimization
Keywords: aqueous two-phase system, batch extraction, continuous microextractor, Extraction, Optimization, xylanase
The extraction of xylanase was performed using an aqueous two-phase system (ATPS) based on polyethylene glycol (PEG1540) and various salts. Preliminary studies in a batch extractor showed that the highest extraction efficiency, E = 79.63 ± 5.21%, and purification factor, PF = 1.26 ± 0.25, were obtained with sodium citrate dihydrate-H2O-PEG1540-based ATPS for an extraction time of 10 min. The process was optimized using the experimental Box-Behnken design at three levels with three factors: extraction time (t), xylanase concentration (γ), and mass fraction of PEG in the ATPS (wPEG). Under optimal process conditions (γ = 0.3 mg/mL, wPEG = 0.21 w/w, and t = 15 min), E = 99.13 ± 1.20% and PF = 6.49 ± 0.05 were achieved. In order to intensify the process, the extraction was performed continuously in microextractors at optimal process conditions. The influence of residence time, different feeding strategies, and channel diameter on extraction efficiency and purification factor was further ex... [more]
Removal of the Pigment Congo Red from Synthetic Wastewater with a Novel and Inexpensive Adsorbent Generated from Powdered Foeniculum Vulgare Seeds
Hatem A. AL-Aoh.
February 27, 2023 (v1)
Subject: Environment
Keywords: Congo red, dynamics, Foeniculum vulgare seed, isotherms, thermodynamics, uptake
In this research, powdered Foeniculum vulgare seed (FVSP) was treated separately with H2C2O4, ZnCl2, and a mixture of ZnCl2-CuS. The characteristics of the treated and untreated FVSP samples, as well as their abilities to eliminate Congo red (CR) from solutions, were investigated. The influences of the empirical circumstances on CR adsorption by the ideal adsorbent were studied. The thermodynamic, isothermal, and dynamic constants of this adsorption were also inspected. The ideal adsorbent was found to be the FVSP sample treated with a ZnCl2-CuS mixture, which eliminated 96.80% of the CR dye. The empirical outcomes proved that this adsorption was significantly affected by the empirical circumstances, and the second-order dynamic model as well as the Langmuir isotherm model fit the empirical data better than the first-order model and the Freundlich model. The values of Ea (15.3 kJ/mol) and ∆Ho (32.767 kJ/mol ≤ ∆Ho ≤ 35.495 kJ/mol) evidence that CR anions were endothermally adsorbed on Z... [more]
Determination of the Bonding Strength of Finger Joints Using a New Test Specimen Geometry
Hannes Stolze, Michael Gurnik, Sebastian Kegel, Susanne Bollmus, Holger Militz.
February 27, 2023 (v1)
Keywords: adhesive joint design, bonding strength, finger joints, finite element simulation, hardwoods, softwoods
In this study, a specimen geometry for testing finger joints was developed using finite element simulation and proofed by experimental testing. Six different wood species and three adhesives were used for finger-jointing specimens. With the test specimen geometry, the bonding strength of the finger joints was determined without the usual self-locking of the joint. Under load, the test specimen geometry introduces maximum stress at the beginning of the bond line (adhesive zone). However, the test specimen geometry does not generate a symmetric stress state. The main difficulty here is the flank angle of the finger joint geometry. The wood species and adhesives significantly influenced the performance of the finger joints.
Effects of Fuel Input on Pulsation Reactor Behavior—An Experimental Study
Jakub Dostál, Stefan Heidinger, Christian Klaus, Simon Unz, Michael Beckmann.
February 27, 2023 (v1)
Subject: Materials
Keywords: pulsatile flow, pulsating combustion, pulsation reactor, thermal material treatment
Material treatment in pulsation reactors (PR) brings the possibility of synthesizing powdery products with advantageous properties, such as nanoparticle sizes and high specific surface areas, at an industrial scale. The extraordinary material properties can be ascribed to special process parameters in a PR, primarily the periodically varying conditions and the consequently enhanced heat and mass transfer between the medium and the particles of the material. Understanding the connections between the PR operation parameters, such as fuel and air intake or PR geometry, and the resulting process parameters (temperature distribution, flow velocity and pressure field, and frequency of the pulsations) is essential to enabling a controllable treatment process. Despite the long history of pulsation reactor technology, many connections and dependencies remain unclear. Thus, the influence of the fuel (and air) supply on the pulsation reactor behavior is experimentally examined in this study. The... [more]
Numerical Simulation of Cavitation Characteristics of a Centrifugal Pump Based on an Improved ZGB Model
Jun Wang, Lun Sun, Yilong Zhou, Yaohui Liu, Fujian Zhao.
February 27, 2023 (v1)
Keywords: cavitation, cavitation model, centrifugal pump, numerical simulation
We modified the Zwart−Gerber−Belamri (ZGB) cavitation and RNG turbulence models based on their rotational motion characteristics, as well as simulating the phenomenon of small fluctuations in rotational speed due to the action of hydraulic excitation force, to increase the precision of numerical simulations of the cavitation characteristics of centrifugal pumps. According to the theory behind the enhanced model, the pressure gradient in the impeller runner changes uniformly, and the cavitation bubble initially manifests itself at the front edge of the blade’s suction. With the reduction in the effective margin, changes in the impeller flow channel’s pressure gradient increased, the blade’s suction-side cavitation area expanded, and the flow field’s internal disturbance enhanced, resulting in hydraulic loss to the centrifugal pump, considerably reduced operating performance, and the blade pressure side by the cavitation-affected area becoming smaller. The blade’s suction-surface pressur... [more]
Crude Oil Bioremediation: From Bacteria to Microalgae
Rosa Paola Radice, Vincenzo De Fabrizio, Antonietta Donadoni, Antonio Scopa, Giuseppe Martelli.
February 27, 2023 (v1)
Subject: Environment
Keywords: bioremediation, crude oil, environmental pollution, hydrocarbons, microalgae, Petroleum
Crude oil is one of the major pollutants present. Its extraction and processing generate processing waters contaminated by hydrocarbons which are harmful to both human health and the flora and fauna that come into contact with it. Hydrocarbon contamination can involve soil and water, and several technologies are used for recovery. The most used techniques for the recovery of spilt oil involve chemical-physical methods that can remove most of the pollutants. Among these, must consider the bioremediation by microorganisms, mostly bacterial capable of degrading many of the toxic compounds contained within the petroleum. Microalgae participate in bioremediation indirectly, supporting the growth of degrading bacteria, and directly acting on contaminants. Their direct contribution is based on the activation of various mechanisms ranging from the production of enzymes capable of degrading hydrocarbons, such as lipoxygenases, to the attack through the liberation of free radicals. The following... [more]
A Technique for Transformer Remnant Cellulose Life Cycle Prediction Using Adaptive Neuro-Fuzzy Inference System
Bonginkosi A. Thango, Pitshou N. Bokoro.
February 27, 2023 (v1)
Keywords: 2-furaldehyde (2FAL), adaptive neuro-fuzzy interference system (ANFIS), cellulose, degree of polymerization (DP), power transformer
This article presents an ultramodern modelling algorithm for predicting the remnant cellulose life cycle for oil-submerged power transformers based on the adaptive neuro-fuzzy interference system (ANFIS). The polymer characteristics, degree of polymerization (DP), and 2-furaldehyde (2FAL) of 100 power transformers were measured and collated, which were apportioned into 70 training databanks and 30 as testing datasets. The remnant cellulose life cycle of the transformer was predicted using the proposed ANFIS model characterized by polymer characteristics, DP and 2FAL as inputs. The proposed approach returns 98.23% training and 99.86% testing reliability. The proposed model was applied to 10 transformer case studies in predicting their remnant cellulose life cycle. To corroborate the proposed ANFIS, a comparative study was carried out by employing existing approaches in predicting the remnant life cycle of the case studies, and significant error margins were observed. At large, the resul... [more]
A Thermal-Fluid-Solid Coupling Computation Model of Initiation Pressure Using Supercritical Carbon Dioxide Fracturing
Yi Chen, Zhihong Kang, Yuzhu Kang, Xiaocheng Chen, Xiaohong Chen, Qingteng Fan, Yukun Du, Jinguang Wang.
February 27, 2023 (v1)
Keywords: hydraulic fracturing, initiation pressure, SC-CO2, tangential stress, thermal-fluid-solid coupling
With the characteristics of low fracturing pressure, little damage to the reservoirs, and assuming the role of carbon storage, supercritical carbon dioxide (SC-CO2) fracturing is suitable for the development of unconventional oil and gas resources. Based on the tensile failure mechanism of rocks, this paper establishes a thermal-fluid-solid coupling initiation pressure model for SC-CO2 fracturing. Using this model, the changes in formation temperature and pore pressure near a wellbore caused by invasion of CO2 into the formation are analyzed, as well as the impact of these changes on the tangential stress of reservoir rocks. The field data of SC-CO2 fracturing in a sandstone gas well are used to validate the reliability of the model. The results show that SC-CO2 fracturing can significantly reduce the initiation pressure, which decreases with the increase in fracturing fluid injection rate. The minimum value of tangential stress is located at the well wall, and the direction of tangent... [more]
Multi-Dataset Hyper-CNN for Hyperspectral Image Segmentation of Remote Sensing Images
Li Liu, Emad Mahrous Awwad, Yasser A. Ali, Muna Al-Razgan, Ali Maarouf, Laith Abualigah, Azadeh Noori Hoshyar.
February 27, 2023 (v1)
Keywords: 3D-CNN, hyperspectral image segmentation (HSI), long short-term memory (LSTM)
This research paper presents novel condensed CNN architecture for the recognition of multispectral images, which has been developed to address the lack of attention paid to neural network designs for multispectral and hyperspectral photography in comparison to RGB photographs. The proposed architecture is able to recognize 10-band multispectral images and has fewer parameters than popular deep designs, such as ResNet and DenseNet, thanks to recent advancements in more efficient smaller CNNs. The proposed architecture is trained from scratch, and it outperforms a comparable network that was trained on RGB images in terms of accuracy and efficiency. The study also demonstrates the use of a Bayesian variant of CNN architecture to show that a network able to process multispectral information greatly reduces the uncertainty associated with class predictions in comparison to standard RGB images. The results of the study are demonstrated by comparing the accuracy of the network’s predictions... [more]
Multi-Objective Collaborative Optimization of Distillation Column Group Based on System Identification
Renchu He, Keshuai Ju, Linlin Li, Jian Long.
February 27, 2023 (v1)
Keywords: clustering, distillation column group, Ethylene, multi-objective optimization, propylene
In this paper, a multi-objective collaborative optimization (MOCO) strategy is proposed for making decisions on a distillation column group. Firstly, based on data preprocessing, the operating modes of the tower group are determined by use of the fuzzy C-means clustering method. Secondly, based on the proposed concept of a collaborative variable, the discrete state-space model of the main towers are constructed by the subspace identification method. Then, a MOCO optimization model is designed for the ethylene plant. Finally, NSGA-III is used to solve the optimization problem. An analysis of a Pareto-optimal frontier and population is carried out. To illustrate the superiority of the proposed strategy, the results are compared with historical data and the appealing operation area is finally obtained.
Ensemble Deep Learning Ultimate Tensile Strength Classification Model for Weld Seam of Asymmetric Friction Stir Welding
Somphop Chiaranai, Rapeepan Pitakaso, Kanchana Sethanan, Monika Kosacka-Olejnik, Thanatkij Srichok, Peerawat Chokanat.
February 27, 2023 (v1)
Keywords: convolution neural network (CNN), ensemble deep learning, friction stir welding (FSW), nondestructive testing, ultimate tensile strength (UTS)
Friction stir welding is a material processing technique used to combine dissimilar and similar materials. Ultimate tensile strength (UTS) is one of the most common objectives of welding, especially friction stir welding (FSW). Typically, destructive testing is utilized to measure the UTS of a welded seam. Testing for the UTS of a weld seam typically involves cutting the specimen and utilizing a machine capable of testing for UTS. In this study, an ensemble deep learning model was developed to classify the UTS of the FSW weld seam. Consequently, the model could classify the quality of the weld seam in relation to its UTS using only an image of the weld seam. Five distinct convolutional neural networks (CNNs) were employed to form the heterogeneous ensemble deep learning model in the proposed model. In addition, image segmentation, image augmentation, and an efficient decision fusion approach were implemented in the proposed model. To test the model, 1664 pictures of weld seams were cre... [more]
Adhesive Thickness and Ageing Effects on the Mechanical Behaviour of Similar and Dissimilar Single Lap Joints Used in the Automotive Industry
Raffaele Ciardiello, Carlo Boursier Niutta, Luca Goglio.
February 27, 2023 (v1)
Subject: Materials
Keywords: ageing cycles, cohesive model, finite element model, polyurethane adhesive, single lap joints
The effects of the adhesive thickness and overlap of a polyurethane adhesive have been studied by using different substrate configurations. Single lap joint (SLJ) specimens have been tested with homologous substrates, carbon fibre-reinforced plastics and painted metal substrates. Furthermore, a configuration with dissimilar substrates has been included in the experimental campaign. Both types of these adhesive and substrates are used in the automotive industry. The bonding procedure has been carried out without a surface treatment in order to quantify the shear strength and stiffness when surface treatments are not used on the substrates, reproducing typical mass production conditions. Three different ageing cycles have been used to evaluate the effects on SLJ specimens. A finite element model that uses cohesive modelling has been built and optimised to assess the differences between the different adopted SLJ configurations.
Fenton Reaction−Unique but Still Mysterious
Frantisek Kastanek, Marketa Spacilova, Pavel Krystynik, Martina Dlaskova, Olga Solcova.
February 27, 2023 (v1)
Subject: Environment
Keywords: advanced oxidation processes, Fenton reaction, Fenton-like reactions, wastewater treatment
This study is devoted to the Fenton reaction, which, despite hundreds of reports in a number of scientific journals, provides opportunities for further investigation of its use as a method of advanced oxidation of organic macro- and micropollutants in its diverse variations and hybrid systems. It transpires that, for example, the choice of the concentrations and ratios of basic chemical substances, i.e., hydrogen peroxide and catalysts based on the Fe2+ ion or other transition metals in homogeneous and heterogeneous arrangements for reactions with various pollutants, is for now the result of the experimental determination of rather randomly selected quantities, requiring further optimizations. The research to date also shows the indispensability of the Fenton reaction related to environmental issues, as it represents the pillar of all advanced oxidation processes, regarding the idea of oxidative hydroxide radicals. This study tries to summarize not only the current knowledge of the Fen... [more]
Can Celecoxib Assay in Preclinical Studies Be Improved?
Maria Mendes, João Sousa, Alberto Pais, Carla Vitorino.
February 27, 2023 (v1)
Subject: Biosystems
Keywords: anticancer, biological matrices, celecoxib, in vivo biodistribution, RP-HPLC
Celecoxib, a cyclooxygenase-2 inhibitor (COX-2), is attracting considerable interest owing to its potential anticancer activity. The repurposing strategy of this drug, however, requires preclinical assessment involving the use of increasingly improved analytical methods. In this work, a rapid, accurate, precise, and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed for the quantification of celecoxib in five mouse matrices (plasma, brain, spleen, liver, and kidney). Chromatographic separation was achieved within 8 min on a reversed-phase C18 column at 35 °C using a mixture of acetonitrile and 2% (v/v) acetic acid (50:50) as mobile phase, at a flow rate of 0.6 mL/min. Celecoxib and curcumin, as the internal standard, were analyzed at 425 nm and 250 nm, respectively. Linearity was observed (r2 ≥ 0.996) in the concentration ranges selected for celecoxib. Overall precision was below 14.9%, and accuracy was between −14.9% and 13.2%. The acceptanc... [more]
A Vertical Fountain Dryer Adjusted for Sawdust and Wood Chips Drying
Konrad Rojcewicz, Zbigniew Oksiuta.
February 27, 2023 (v1)
Keywords: chips, fountain dryer, sawdust, sawdust drying, wood fuel
This article presents the preliminary results on the drying process in a fountain dryer designed and adapted to drying waist sawdust and/or chips of various morphology and moisture content. In terms of drying technology, it is important to reduce the demand for heat and electricity. The phenomena occurring during the drying of sawdust in a fountain dryer were analyzed. Modifications of a typical fountain dryer were proposed in order to dry the chips, to obtain appropriate moisture and quality suitable for the process of their further granulation for the production of pellets. The test stand and the most important properties of the fountain dryer were described and discussed. Such characteristic aims of the device, i.e., efficiency, combustion, air and exhaust gas flow measurements, among others, were presented. The characteristics of the sawdust drying curves as a function of temperature were also determined. Computer simulations of heat exchange, air, and exhaust gas flow velocities w... [more]
Conversion of Carbonaceous Organic Impurities (Methyldichlorosilane) in Trichlorosilane Using Weakly Basic Anion-Exchange Resin as Solid Catalyst
Jianhua Liu, Miaolei Zhang, Guoqiang Huang.
February 27, 2023 (v1)
Subject: Materials
Keywords: anion-exchange resin, de(hydro)halogenization, heterogeneous catalysis, methyldichlorosilane, tetrachlorosilane
Trichlorosilane (SiHCl3) is an important raw material for preparing solar cells and semiconductor chips in the Siemens method. Since the boiling points of SiHCl3 and methyldichlorosilane (CH3SiHCl2) are close to each other, it is difficult to remove CH3SiHCl2 from the raw material to obtain high-purity products by traditional distillation methods. Therefore, we propose an efficient catalytic approach to convert CH3SiHCl2 to methyltrichlorosilane (CH3SiCl3) with an anion-exchange resin as the catalyst and tetrachlorosilane (SiCl4) as the Cl donor in a continuous-flow fixed bed reactor. Seven anion-exchange resins, including D201, D301, D303, 201 × 7, D301F, D315 and D380 were evaluated. The results showed that D301 resin had the best performance. Reaction conditions such as reaction temperature, reactant molar ratio and catalyst stability were investigated. The maximum conversion of CH3SiHCl2 was 60% at an optimum reaction temperature of 150 °C, n(CH3SiHCl2):n(SiCl4) = 1:3 and a liquid... [more]
Overlying Strata Dynamic Movement Law and Prediction Method Caused by Longwall Coal-Mining: A Case Study
Guosheng Xu, Dehai Li, Yanbin Zhang, Huigui Li.
February 27, 2023 (v1)
Keywords: dynamic movement, log distance of maximum subsidence velocity, maximum subsidence velocity, overlying strata movement, surface subsidence
The surface subsidence caused by underground mining is a spatiotemporal process. The impact of mining on surface structures (houses, highways, railways, dikes, etc.) and structures in rock strata (shafts, roadways, chambers, etc.) is a dynamic process. It is necessary to study the dynamic movement law of the surface and overlying strata in the mining process of the working face to predict the extent of the impact of mining on the aforementioned structures. It provides a reference for pre-reinforcement and post-mining treatment. This paper studies the variation of surface dynamic movement based on the survey line above the working face of Peigou Coal Mine. The numerical simulation model of the overlying strata dynamic movement is established to study the dynamic movement law of rock strata with different depths, and the fitting function of surface and overlying strata dynamic movement is determined. Finally, the subsidence velocity prediction function of the major section of the surface... [more]
Multi-Population Genetic Algorithm and Cuckoo Search Hybrid Technique for Parameter Identification of Fermentation Process Models
Maria Angelova, Olympia Roeva, Peter Vassilev, Tania Pencheva.
February 27, 2023 (v1)
Keywords: cuckoo search, E. coli, fed-batch fermentation models, hybrid technique, multi-population genetic algorithm, parameter identification, S. cerevisiae
In this paper, a new hybrid MpGA-CS is elaborated between multi-population genetic algorithm (MpGA) and cuckoo search (CS) metaheuristic. Developed MpGA-CS has been adapted and tested consequently for modelling of bacteria and yeast fermentation processes (FP), due to their great impact on different industrial areas. In parallel, classic MpGA, classic CS, and a new hybrid MpGA-CS have been separately applied for parameter identification of E. coli and S. cerevisiae FP models. For completeness, the newly elaborated MpGA-CS has been compared with two additional nature-inspired algorithms; namely, artificial bee colony algorithm (ABC) and water cycle algorithm (WCA). The comparison has been carried out based on numerical and statistical tests, such as ANOVA, Friedman, and Wilcoxon tests. The obtained results show that the hybrid metaheuristic MpGA-CS, presented herein for the first time, has been distinguished as the most reliable among the investigated algorithms to further save computat... [more]
Prediction of Molecular Weight of Petroleum Fluids by Empirical Correlations and Artificial Neuron Networks
Dicho Stratiev, Sotir Sotirov, Evdokia Sotirova, Svetoslav Nenov, Rosen Dinkov, Ivelina Shishkova, Iliyan Venkov Kolev, Dobromir Yordanov, Svetlin Vasilev, Krassimir Atanassov, Stanislav Simeonov, Georgi Nikolov Palichev.
February 27, 2023 (v1)
Keywords: artificial neural network, empirical correlation, Modelling, molecular weight, nonlinear regression, Petroleum
The exactitude of petroleum fluid molecular weight correlations affects significantly the precision of petroleum engineering calculations and can make process design and trouble-shooting inaccurate. Some of the methods in the literature to predict petroleum fluid molecular weight are used in commercial software process simulators. According to statements made in the literature, the correlations of Lee−Kesler and Twu are the most used in petroleum engineering, and the other methods do not exhibit any significant advantages over the Lee−Kesler and Twu correlations. In order to verify which of the proposed in the literature correlations are the most appropriate for petroleum fluids with molecular weight variation between 70 and 1685 g/mol, 430 data points for boiling point, specific gravity, and molecular weight of petroleum fluids and individual hydrocarbons were extracted from 17 literature sources. Besides the existing correlations in the literature, two different techniques, nonlinear... [more]
Experimental Research on the Influence of Short-Term Noise Exposure on Miners’ Physiology
Jing Li, Zhongjie Cai, Huiyan Liu, Yanli Xin.
February 27, 2023 (v1)
Keywords: coal mine safety, human health, occupational noise, physiology indicator
Coal mine noise affects human physiology, psychology, and behavior. It causes errors at work and increases accidents. In this study, we built a coal mine noise simulation experiment system. The system not only included an experimental environment simulation system and a physiological indicator test system, but it also added a miners’ working simulation system. This paper aimed to study the effect of different short-term (25 min) noise levels (60 dB, 70 dB, 80 dB, 90 dB, and 100 dB) on human physiology (skin conductivity and heart rate). Critical analysis showed that the stronger the noise intensity is, the shorter the contact time it takes for physiological indicators to present significant changes, and by setting different noises and measuring the skin conductivity and heart rate of human body, it was concluded that the noise level should be reduced to 90 dB to reduce accidents of miners.
Transient Modeling and Performance Analysis of Hydrogen-Fueled Aero Engines
Xiting Wang, Ai He, Zhongzhi Hu.
February 27, 2023 (v1)
Keywords: hydrogen-fueled aero engine, performance analysis, transient modeling
With the combustor burning hydrogen, as well as the strongly coupled fuel and cooling system, the configuration of a hydrogen-fueled aero engine is more complex than that of a conventional aero engine. The performance, and especially the dynamic behavior of a hydrogen-fueled aero engine, need to be fully understood for engine system design and optimization. In this paper, both the transient modeling and performance analysis of hydrogen-fueled engines are presented. Firstly, the models specific to the hydrogen-fueled engine components and systems, including the hydrogen-fueled combustor, the steam injection system, a simplified model for a quick NOx emission assessment, and the heat exchangers, are developed and then integrated to a conventional engine models. The simulations with both Simulink and Speedgoat-based hardware in the loop system are carried out. Secondly, the performance analysis is performed for a typical turbofan engine configuration, CF6, and for the two hydrogen-fueled... [more]
Evaluation of the Processing of Multi-Crop Plants into Pelletized Biofuel and Its Use for Energy Conversion
Rita Petlickaitė, Algirdas Jasinskas, Rolandas Domeika, Nerijus Pedišius, Egidijus Lemanas, Marius Praspaliauskas, Savelii Kukharets.
February 27, 2023 (v1)
Keywords: fibrous hemp, field bean, harmful emissions, intercropping, maize, pellets utilization, solid fuel
Multi-crop plants (fibrous hemp, maize, and faba bean) can potentially be an alternative to wood biomass pellets, but there is no detailed knowledge to support the suitability of this biomass for solid biofuel production. The aim of this study is to analyze and justify the suitability of multi-crop plant biomass for the production of biofuel pellets and to assess the environmental impact of burning them. This paper presents studies of physical-mechanical, thermal, and chemical characteristics of biofuel pellets from multi-crop plants and emissions during their combustion under laboratory conditions. The main parameters of the produced pellets were determined according to international standards, which are detailed in the methodology part. The length of the produced pellets ranged from 17.6 to 26.6 mm, and the diameter was about 6 mm. The density of wet pellets varied from 1077.67 to 1249.78 kg m−3. The amount of ash in the pellets varied from 5.75% to 8.02%. Determined lower calorific... [more]
Rehydration Activity of High-Temperature Calcined Recycled Sand Autoclaved Aerated Concrete
Xiuli Yang, Renmiao Zhu, Bin Xu.
February 27, 2023 (v1)
Subject: Materials
Keywords: autoclaved aerated concrete, calcined, electrical conductivity, hydration heat, rehydration activity, strength activity index
Autoclaved aerated concrete is an excellent thermal insulation wall material, but with a large amount of waste. This paper describes the high-temperature activation and rehydration activity of waste cement−lime−sand autoclaved aerated concrete (SAAC) and discusses the high-temperature phase transition of SAAC. SAAC calcined at 750 °C was confirmed to be a metastable and amorphous state, which could hydrolyze Ca2+ ions with reactivity in water. The conductivity curve demonstrates that the concentration of ions in the suspension decreases rapidly at 150−250 min, and the hydration reaction turns dominant at this time. The hydration heat curve also displays a hydration exothermic peak at 2.5 h. In addition, the conductivity measurement of suspension and the exothermic measurement of hydration reaction proves that SAAC calcined at 750 °C has a hydration activity and can rehydrate with SiO2 in the system. The rehydration activity was verified by replacing 30% cement in the standard test bloc... [more]
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