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Showing records 3584 to 3608 of 43292. [First] Page: 1 141 142 143 144 145 146 147 148 149 Last
Efficiency and Sustainability: The Role of Digitization in Re-Inhabiting the Existing Building Stock
Federico Cinquepalmi, Spartaco Paris, Elisa Pennacchia, Virginia Adele Tiburcio.
May 23, 2023 (v1)
Keywords: adaptive reuse, building efficiency, building information modeling, data analytics, energy savings, geographic information system, multicriteria evaluation tools.
Cities are complex and constantly evolving systems where changing social needs have always reshaped the built environment. Considering recent evolutionary trends in housing emergencies, amplified by the COVID-19 pandemic, and environmental sustainability goals, a rethinking of the building heritage is fundamental. This article aims to promote the conversion of buildings designed initially for nonresidential uses as a process and project strategy based on energy efficiency and a holistic and integrated vision of the circular economy. The methodological approach is based on two main phases: definition of evaluative parameters for the potential reuse of a building, and integration of the evaluation system in a BIM and GIS environment. The result is a tool for rapid automatic pre-evaluation of the potential conversion of a building into a residential space. Applying the developed methodology allows for a practical approach to the significant issue of sustainable construction, with particul... [more]
Greenhouse Gas Balance in the City of Reggio Calabria and Assessment of the Effects of Measures of Emission Reduction and Absorption
Concettina Marino, Antonino Nucara, Maria Francesca Panzera, Matilde Pietrafesa.
May 23, 2023 (v1)
Subject: Environment
Keywords: emission absorption, emission mitigation measures, greenhouse gas emission balance, IPCC methodology.
Climate change and its ascertained attribution to anthropic activity need to be tackled with extreme urgency and must not be postponed. The need to reduce greenhouse gas emissions require a change in the energy paradigm, mainly affecting the construction and mobility sectors. Countries need to move towards climate neutrality with a widespread adoption of innovative models, systems, and technologies, reducing dependence on non-renewable sources and increasing energy efficiency. Measures to be adopted to achieve the prefixed decarbonization targets should involve, in addition to central governments, local communities. In this paper, in order to contribute to the definition of mitigation measures by the local administration, the balance of emissions and removal of greenhouse gases, assessed following the IPCC guidelines, for an Italian city (Reggio Calabria) on the date of 1 January 2020 is presented. Several hypotheses concerning reduction measures to be applied to the building and trans... [more]
Wind Turbine Drivetrain Condition Monitoring through SCADA-Collected Temperature Data: Discussion of Selected Recent Papers
Davide Astolfi.
May 23, 2023 (v1)
Wind energy is going to be the leading renewable source of the next decades [...]
Investigating the Potential of Nuclear Energy in Achieving a Carbon-Free Energy Future
Jānis Krūmiņš, Māris Kļaviņš.
May 23, 2023 (v1)
Keywords: carbon-neutral energy, decarbonization, nuclear power, power generation, Renewable and Sustainable Energy, small modular reactor.
This scientific paper discusses the importance of reducing greenhouse gas emissions to mitigate the effects of climate change. The proposed strategy is to reach net-zero emissions by transitioning to electric systems powered by low-carbon sources such as wind, solar, hydroelectric power, and nuclear energy. However, the paper also highlights the challenges of this transition, including high costs and lack of infrastructure. The paper emphasizes the need for continued research and investment in renewable energy technology and infrastructure to overcome these challenges and achieve a sustainable energy system. Additionally, the use of nuclear energy raises concerns, such as nuclear waste and proliferation, and should be considered with its benefits and drawbacks. The study assesses the feasibility of nuclear energy development in Latvia, a country in Northern Europe, and finds that Latvia is a suitable location for nuclear power facilities due to potential energy independence, low-carbon... [more]
Grid-Connected Converters: A Brief Survey of Topologies, Output Filters, Current Control, and Weak Grids Operation
Guilherme V. Hollweg, Shahid A. Khan, Shivam Chaturvedi, Yaoyu Fan, Mengqi Wang, Wencong Su.
May 23, 2023 (v1)
Keywords: active damping, current control, grid-connected converters, LCL, output filters, passive damping, topologies, weak grids.
Grid-connected converters (GCCs) are used extensively for the integration of DC power sources with AC power sources. However, since it is a complex topic, there are many possibilities for regulating grid-injected currents, as well as different modulation techniques for generating full-bridge PWM voltages. The control techniques are directly related to the type of output filter, as well as to the topology of the converter, since a complex plant can require more sophisticated controllers to keep the system stable, and with good regulation performance. Furthermore, a discussion of the applicability of these converters in weak and very weak grids with high inductance content has recently been growing, which adds a greater degree of complexity to the control structure of the converter. In this brief overview are outlined some topics about topologies, output filters, and control, focusing on the current regulation of grid-connected converters. In addition, a discussion of the main challenges... [more]
Diffusion Absorption Refrigeration Systems: An Overview of Thermal Mechanisms and Models
Baby-Jean Robert Mungyeko Bisulandu, Rami Mansouri, Adrian Ilinca.
May 23, 2023 (v1)
Keywords: ARS/DAR systems, energy performance, energy sources, generator/bubble pump design, hybrid ARS/DAR, thermal mechanisms.
The energy transition, originating in the limitation of fossil resources and greenhouse gas (GHG) emission reduction, is the basis of many studies on renewable energies in different industrial applications. The diffusion absorption refrigeration machines are very promising insofar as they allow the use of renewable resources (solar, geothermal, waste gas, etc.). This technology is often considered an alternative to vapor compression systems in cooling and refrigeration applications. This paper aims to overview the thermal mechanisms related to modeling system energy sources and highlight the primary methodologies and techniques used. We study and analyze the technology’s current challenges and future directions and, finally, identify the gaps in the existing models to pave the way for future research. The paper also gives a classification of absorption refrigeration systems (ARS) to position and limit the scope of the study. The paper will help researchers who approach the various aspe... [more]
In-Situ Generation of Nitrogen-Doped MoS2 Quantum Dots Using Laser Ablation in Cryogenic Medium for Hydrogen Evolution Reaction
Fatemeh Shahi, Parviz Parvin, Seyedeh Zahra Mortazavi, Ali Reyhani, Mohtada Sadrzadeh, Ali Moafi, Mahdi Ebrahimi, Mohammadreza Aghaei.
May 2, 2023 (v1)
Keywords: hydrogen evolution reaction, liquid nitrogen, MoS2 quantum dots, nitrogen doping, pulsed laser ablation.
Here, nitrogen doped molybdenum disulfide quantum dots (N-MoS2 QDs) are fabricated by making use of the pulsed laser ablation (PLA) process in liquid nitrogen (LN2) as a dopant agent. In fact, LN2 contributes the rapid condensation of the plasma plume to form MoS2 QDs, optimizing the conditions for the synthesis of N-doped MoS2 with p-type property. The structural/optical features of the synthesized products are studied using transmission electron microscopy (TEM), absorption spectroscopy, photoluminescence (PL) spectroscopy techniques, and X-ray photoelectron spectroscopy (XPS). The TEM image shows the creation of MoS2 QDs with 5.5 nm average size. UV-vis and PL spectroscopy confirm the formation of N-MoS2 QDs according to the dominant peaks. The Tuck plot gives a direct band-gap of 4.34 eV for MoS2 QDs. Furthermore, XPS spectroscopy reveals Mo-N bonding, indicating nitrogen doping as evidence of p-type MoS2 QDs. Thus, PLA provides a single-stage way to the clean and green synthesis o... [more]
Empirical Study on the Low-Carbon Economic Efficiency in Zhejiang Province Based on an Improved DEA Model and Projection
Hongyun Luo, Xiangyi Lin.
May 2, 2023 (v1)
Subject: Energy Policy
Keywords: efficiency calculation, improved DEA model, low-carbon economy, low-carbon efficiency, projection.
Low-carbon economic efficiency is an important indicator that can be used to measure the quality of regional economic development. In this study, an improved DEA model is introduced into the calculation of low-carbon economic efficiency in Zhejiang Province. Using the actual data of nine prefecture-level cities in Zhejiang Province from 2015 to 2020, the low-carbon economic efficiency of each prefecture-level city is calculated. The result is that the overall low-carbon economic efficiency of Zhejiang Province indicates a trend of first falling and then rising, and the low-carbon economic efficiencies of different prefecture-level cities largely differ. The causes of six inefficient DMUs (prefecture-level cities) are analyzed using projection. The improved DEA model is used to determine the “expansion coefficient” of the input and output of three DMUs (prefecture-level cities) with relatively low-carbon economic efficiency. The research results provide a strong basis and support for th... [more]
DFT Prediction of Radiolytic Stability of Conformationally Flexible Ligands
Anastasiia Smirnova, Maksim Yablonskiy, Vladimir Petrov, Artem Mitrofanov.
May 2, 2023 (v1)
Keywords: DFT, diglycolamides, Extraction, irradiation, radiolytic stability, spent nuclear fuel.
Radiolytic stability is one of the main requirements of the ligands for the reprocessing of spent nuclear fuel. The prediction of radiation stability based only on the 2D molecular structural formula allows us to accelerate and simplify the development of new ligands. Here, we used quantum chemistry to investigate the radiolytic behavior of water-soluble diglycolamides as one of the most popular ligands for spent nuclear fuel reprocessing. The accurate accounting of conformational mobility in the descriptors based on the Frontier Orbital Fukui theory allowed us to obtain a good correlation between theoretical and experimental data.
A Novel Workflow for Early Time Transient Pressure Data Interpretation in Tight Oil Reservoirs with Physical Constraints
Tongjing Liu, Liwu Jiang, Jinju Liu, Juan Ni, Xinju Liu, Pengxiang Diwu.
May 2, 2023 (v1)
Keywords: early time transient data, new type curves, physical constraints, pseudo threshold pressure gradient (TPG), skin factor, tight oil reservoirs.
In this work, a novel workflow has been proposed, validated and applied to interpret the early time transient pressure data in tight oil reservoirs with physical constraints. More specifically, the theoretical model was developed to obtain the transient pressure response for a vertical well in tight oil reservoirs with consideration of pseudo threshold pressure gradient (TPG). Then, a physical constraint between the skin factor and formation permeability has been proposed based on the physical meaning of percolation theory. This physical constraint can be applied to determine the lower limit of the skin factor which can reduce the uncertainty during the interpretation process. It is found that the influence range of the skin factor and permeability may partially overlap during the interpretation process without consideration of physical constraints. Additionally, it is found that the equivalent wellbore radius is more reasonable by considering the skin factor constraints. Furthermore,... [more]
Effects of Depositional Processes in Submarine Canyons and Distribution of Gas Chimneys on Gas Hydrate Accumulation in the Shenhu Sea Area, Northern South China Sea
Yunlong He, Zenggui Kuang, Cong Cheng, Tao Jiang, Cheng Zhang, Biyu Lu, Chengzhi Yang, Jiayu Liu, Changlong Xiang.
May 2, 2023 (v1)
Subject: Other
Keywords: accumulation, depositional process, gas chimney, gas hydrate, South China Sea, submarine canyon.
Previous gas hydrate production tests conducted by the Guangzhou Marine Geological Survey (GSGM) in 2017 and 2020 indicated the great potential of gas hydrates in the Shenhu Sea area in the Pearl River Mouth Basin (PRMB), China. In this study, the effects of deposition processes in submarine canyons and the distribution of gas chimneys on gas hydrate accumulation were investigated using high-resolution two- dimensional (2D) and three-dimensional (3D) seismic data. Four intact submarine canyons were identified in the study area. Five deepwater depositional elements are closely related to submarine canyons: lateral accretion packages (LAPs), basal lags, slides, mass transport deposits (MTDs), and turbidity lobes. MTDs and lobes with multiple stages outside the distal canyon mouth reveal that the sedimentary evolution of the canyon was accompanied by frequent sediment gravity flows. Gas chimneys originating from Eocene strata are generally up to 3 km wide and distributed in a lumpy or ban... [more]
Deep Reductions in Energy Use: Hobson’s Choice in Climate’s Last-Chance Saloon
Damon Honnery, Patrick Moriarty.
May 2, 2023 (v1)
Subject: Energy Policy
In 2022, the record of extreme weather events already includes deep droughts in Sichuan province, China, and California, US; floods inundating a third of Pakistan and serious and repeated flooding in Eastern Australia; heat waves and drought in Europe; and wildfires in Europe and the western US [...]
Experimental Investigation on the Noise Characteristics of a Squirrel-Cage Fan with Different Blade Lengths
Zhehong Li, Wenbin Cao, Xinxue Ye, Yikun Wei.
May 2, 2023 (v1)
Subject: Other
Keywords: blade length, noise, squirrel-cage fan, synchronously measurement.
Squirrel-cage fans are widely applied in air conditioning systems, and their aerodynamic noise mainly related to blade length. The aerodynamic performance and noise spectrum of squirrel-cage fans are synchronously measured in an anechoic wind tunnel. The effect of blade lengths and different geometric configurations on the noise of a squirrel-cage fan is experimentally investigated. This paper focuses on the total sound pressure level and noise spectrum characteristics at different measurement points. Noise distributions of the outlet of the forward squirrel-cage fan exhibited axial-symmetry and large differences for those of vertical direction. In lower fan positions, the noise was greater than that of the top. In particular, it was found that blades were easy to generate higher noise when their length was reduced by 31.7%. The findings suggest that the broadband noise of the squirrel-cage fan should be fully considered for noise reduction. The purpose of this work is to provide a nov... [more]
Electrical Phenomena on Fully Airborne Vertical Electric Antennas in Extreme Weather Conditions
Tomasz Aleksander Miś, Józef Modelski.
May 2, 2023 (v1)
Keywords: airborne, balloon, cloud, storm, VED, VLF.
This is a conference extension of the paper ‘Investigation on the mature storm cloud’s electric field using long airborne antennas’. The use of vertical antennas (including the VEDs—Vertical Electric Dipoles), lifted up by aerostats to high altitudes without being anchored to the ground, presents numerous advantages in comparison with large terrestrial VLF (Very Low Frequency) antenna structures. A slow-moving floating-earth conductor—a vertical wire antenna—is subjected to intense electrification mechanisms in the atmosphere and inside the cloud layers, producing additional risks for the transmitter and the flight train itself. The electrical potential achieved in this process is, therefore, compared with the flashover voltages over the antenna’s upper fixing point, defining the voltage margins at which the VLF transmitter is able to operate. The electrification processes are also compared to the model based on experimental data on the occurrence of corona discharges over a long, vert... [more]
Perspectives on Hydrogen
Alberto Abánades.
May 2, 2023 (v1)
Keywords: decarbonisation, education, energy vector, Hydrogen, implementation, regulation, reskilling.
Humankind has an urgent need to reduce carbon dioxide emissions. Such a challenge requires deep transformation of the current energy system in our society. Achieving this goal has given an unprecedented role to decarbonized energy vectors. Electricity is the most consolidated of such vectors, and a molecular vector is in the agenda to contribute in the future to those end uses that are difficult to electrify. Additionally, energy storage is a critical issue for both energy vectors. In this communication, discussion on the status, hopes and perspectives of the hydrogen contribution to decarbonization are presented, emphasizing bottlenecks in key aspects, such as education, reskilling and storage capacity, and some concerns about the development of a flexible portfolio of technologies that could affect the contribution and impact of the whole hydrogen value chain in society. This communication would serve to the debate and boost discussion about the topic.
Experimental Investigation of Heat Pipe Inclination Angle Effect on Temperature Nonuniformity in Electrical Machines
Xiaochen Zhang, Han Zhao, Jing Li, Fengyu Zhang, Yue Zhang, Hongyu Yan, Zhihao Niu, David Gerada, He Zhang.
May 2, 2023 (v1)
Keywords: electrical machine, experimental investigation, heat pipe, inclination angle, temperature distribution, temperature nonuniformity.
Heat pipes (HPs) are gaining increasing popularity in the propulsion motors of transportation electrification due to their remarkable thermal properties. However, the inclination angle affects the HP thermal performance and, thus, results in temperature nonuniformity, which may generate unbalanced thermal stress on the motor. Such an issue has received less attention to date and requires corresponding solutions. This article performs an experimental investigation on motor temperature nonuniformity with HPs and further proposes an improved structure to address this problem. A specimen based on a stator-winding assembly with HPs is prepared and a dedicated experimental platform is established. Then, the temperature distribution across the specimen is studied, followed by an evaluation of the effects of current density and wind velocity. To compensate for the degradation of HP thermal performance, an improved structure with enlarged fins is proposed, and the equilibrium point is determine... [more]
Prediction Method and Application of Hydrocarbon Fluid Migration through Faulted Cap Rocks
Bowei Zhang, Guang Fu.
May 2, 2023 (v1)
Subject: Other
Keywords: faulted cap rocks, hydrocarbon fluid migration, prediction method.
Hydrocarbon fluid migration through faulted cap rocks was determined by comparing the maximum connected thickness of cap rocks required for hydrocarbon fluid migration and the actual values, since cap rocks are important in the study of hydrocarbon fluid distribution in petroliferous basins based on its migration mechanism(s). The maximum connected thickness required was identified by comparing the cap rocks, fault displacement, and oil/gas distribution. The hydrocarbon fluid at the Putaohua reservoir migrated to the overlying Saertu and Heidimiao reservoirs in the Bayan Chagan Area, northern Songliao Basin. This was predicted to demonstrate the validity of the method. The results show that the adjusted Putaohua oil reservoir was distributed near the Talahai fault and Bayanchagan fault, rather than the Gulong sag in the southwest of the study area, where oil migrated vertically through the Sapu cap rocks to the overlying Saertu reservoir. Thick mudstone cap rocks in the second member o... [more]
Linearly Polarized Antenna Boosters versus Circularly Polarized Microstrip Patch Antennas for GPS Reception in IoT Devices
Jaime Gui, José L. Leiva, Aurora Andújar, Jaap Groot, Joan L. Pijoan, Jaume Anguera.
May 2, 2023 (v1)
Keywords: antenna, antenna boosters, GPS, IoT, polarization, TTFF (time to first fix).
GPS has become an attractive feature for geolocalization enabling asset tracking IoT devices. GPS satellite antennas radiate RHCP (right-hand circularly polarized) electromagnetic waves; thus, the typical antenna at the receiver is also RHCP. However, when the orientation of the receiving device is random, linear polarization antennas operate better in terms of TTFF (time to first fix). Through field measurements (urban and field) and considering different positions of the device in a vehicle, an RHCP microstrip patch antenna and a linear non-resonant antenna element called an antenna booster were compared. TTFF averaged for several positions was 7 s better for the linearly polarized antenna booster than for the microstrip RHCP patch antenna. The results demonstrate that the behavior of the linear polarization antenna booster technology is more robust in terms of TTFF to the arbitrary position of the IoT device while keeping a small size and simplicity.sdf
Sterical Driving Minor Actinide Selectivity of Bi-pyridyl Diamides: Ortho- vs. Para-Substitution
Nataliya E. Borisova, Tsagana B. Sumyanova, Alexey V. Ivanov, Anastasia V. Kharcheva, Petr I. Matveev, Svetlana V. Patsaeva, Vladimir G. Petrov.
May 2, 2023 (v1)
Subject: Materials
Keywords: HLW, lanthanide ions, liquid extraction, luminescence, quantum yield of luminescence, stability constants.
Hybrid donor extractants are a promising class of compounds for the separation of trivalent actinides and lanthanides. In this paper, we present a new ligand from the bipyridyl-dicarboxylic acid diamide family—N,N’-diethyl-N,N’-bis(2,4,5-trimethylphenyl)-[2,2’-bipyridine]-6,6’-dicarboxamide. The synthesis of N-ethyl-2,4,5-trimethylaniline from pseudocumene by selective acetylation is presented. The target ligand was obtained using this aminylene. Chemical synthesis of its complexes with Ln(NO3)3 and their spectroscopic analysis showed that the structure of the complexes is near to the corresponding structures of well-known di-methylated dianilides. A series of studies on the photophysical, complexing, and extraction properties of this ligand and its complexes were carried out. It was shown that the extraction system based on this ligand can selectively isolate americium from the solution of high-level waste imitator.
New Insights into the Genetic Mechanism of the Miocene Mounded Stratigraphy in the Qiongdongnan Basin, Northern South China Sea
Litao Xu, Wanzhong Shi, Ren Wang, Jinfeng Ren, Yulin He, Hao Du, Tingna Zuo, Jin Huang, Yang Dong.
May 2, 2023 (v1)
Subject: Other
Keywords: detachment faults, genetic mechanism, gravity gliding, mounded stratigraphy, Qiongdongnan Basin, slope instability.
The origin of deep-water mounds has been a topic of debate in recent years. In this study, newly collected seismic data were employed to characterize the mounds within the Meishan Formation in the Qiongdongnan Basin and a novel model was proposed. The result showed that pervasive mounds and ‘V’-shaped troughs were alternately distributed at the top of the Meishan Formation. They appeared as elongated ridges flanked by similarly elongated gullies, with the trending parallel with the strike of the basinward slope. The mounded features were considered to be formed in response to the tectonically induced seabed deformation. The differential subsidence steepened the slope that was equivalent to the top of the Meishan Formation (ca. 10.5 Ma), which offered sufficient driving forces triggering the slope’s instability. Correspondingly, the uppermost deposits glided along a bedding-parallel detachment surface, creating a number of listric detachment faults that ceased downward to this surface.... [more]
Innovation and Climate Change Mitigation Technology in the Asian and African Mining Sector: Empirical Analysis Using the LMDI Method
Cety Gessica Abraham Mahanga Tsoni, Railh Gugus Tresor Massonini Ngoma, Xiangrui Meng.
May 2, 2023 (v1)
Subject: Energy Policy
Keywords: Africa, Asia, climate change mitigation technology, innovation, mining.
Technology plays an essential role as climate change becomes a growing concern worldwide. This article aims to examine the influence that innovation exerts on climate change mitigation technology (CCMT) in the African and Asian mining sectors. Data were collected from the World Intellectual Property Organization mining database. We conducted a decomposition analysis of patent families between 2011 and 2020 based on the Logarithmic Mean Divisia Index (LMDI) method. Findings revealed that African countries do not devote their innovation efforts to adaptive technologies, resulting in a mismatch between mining and access to technologies as the scope of R&D narrows. In Asia, the drive for innovation and technological efficiency is a tool to prevent economic damage and legitimize technological benefits as solutions for climate change mitigation technology. This outcome calls on political, national, and international governments to bridge the innovation gap to trigger a real shift from innova... [more]
Effect of Stress on Variations in the Magnetic Field of Ferromagnetic Steel under a Constant DC Magnetic Field
Bin Yang, Yang Gao, Lin Liu, Zhifeng Liu, Yue Yu, Ruimin Wang.
May 2, 2023 (v1)
Subject: Materials
Keywords: magnetization, magneto-mechanical effect, normal component of surface magnetic field, stress.
In this paper, variations in the normal component of the magnetic field BZ on the surface of Q195 steel specimens produced by simultaneous application of noncoaxial DC magnetic field and stress were studied by tensile tests. It was found that there was no shift in the direction of BZ variations when the specimens were magnetized parallel to stress, whereas the direction of BZ variations shifted a slight angle relative to the DC magnetic field when the specimens were magnetized perpendicular to stress. The amplitude of BZ increased with stress from 0 MPa to 120 MPa when the stress was parallel to the DC magnetic field. On the contrary, the amplitude of BZ decreased with stress from 0 MPa to 120 MPa when the stress was perpendicular to the DC magnetic field. The mechanisms underlying the experimental characteristics are also discussed. This research provides the possibility for quantitative inspection of the stress in ferromagnetic steels using surface magnetic field measurements.
Impact of a HVDC Link on the Reliability of the Bulk Nigerian Transmission Network
Omowumi Grace Olasunkanmi, Waliu O. Apena, Andrew R. Barron, Alvin Orbaek White, Grazia Todeschini.
May 2, 2023 (v1)
Keywords: load-point indices, reliability, transmission network, VSC-HVDC.
Regular and reliable access to energy is critical to the foundations of a stable and growing economy. The Nigerian transmission network generates more electricity than is consumed but, due to unpredicted outages, customers are often left without electrical power for several hours during the year. This paper aims to assess the present reliability indices of the Nigerian transmission network, and to determine the impact of HVDCs on system reliability. In the first part of this paper, the reliability of the Nigerian transmission system is quantified by building a model in DIgSILENT PowerFactory and carrying out a reliability study based on data provided by the Nigerian transmission-system operator. Both network indices and load-point indices are evaluated, and the weakest points in the network are identified. In the second part of the paper, an HVDC model is built and integrated into the existing network at the locations identified by the reliability study. A comparative study using two d... [more]
Sintering of Industrial Uranium Dioxide Pellets Using Microwave Radiation for Nuclear Fuel Fabrication
Konstantin S. Pilyushenko, Maxim S. Dmitriyev, Sergey E. Vinokurov, Trofim I. Trofimov, Boris V. Saveliyev, Alexander I. Kuznetsov, Alexander A. Uvarov, Boris F. Myasoedov.
May 2, 2023 (v1)
Keywords: fuel pellets, microwave radiation, sintering, uranium dioxide.
In this study, the possibility of sintering industrial pressed uranium dioxide pellets using microwave radiation for the production of nuclear fuel is shown. As a result, the conditions for sintering pellets in an experimental microwave oven (power 2.9 kW, frequency 2.45 GHz) were chosen to ensure that the characteristics of the resulting fuel pellets meet the regulatory requirements for ceramic nuclear fuel, including the following: a density of about 10.44 g/cm3; a volume fraction of open pores of tablets of about 0.1%; an oxygen coefficient of no more than 2.002; hydrogen content of about 0.30 ppm; and the change in density after re-sintering on average no more than 1.16%.
Study of the NH3-SCR Mechanism on LaMnO3 Surfaces Based on the DFT Method
Dongdong Ren, Kai Wu, Siyi Luo, Yongjie Li, Keting Gui, Zongliang Zuo, Xianjun Guo.
May 2, 2023 (v1)
Keywords: DFT, LaMnO3, NH3-SCR, NOx removal.
LaMnO3 with perovskite structure is a SCR de-NOx catalyst with good performance at low temperatures. In this paper, the SCR reaction process on the 010 surface of LaMnO3 catalyst was studied by DFT method, to guide the development of catalysts and their effective application. The results obtained through research indicate that both E-R and L-H mechanisms exist on the catalyst surface. The NH3 molecule can be absorbed on L acid and then oxidized by lattice oxygen to form NH2. Then, NH2 can react with the NO molecule to form NH2NO and decompose to N2 and H2O. The NH3 can also be absorbed with hydroxyl to form NH4+, it can also react with NO to form NH2NO and then decompose. The NH4+ also can react with NO3− which is formed by NO oxidized when O2 is present, to participate in the rapid SCR process.
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