检索结果-南通市图书馆

Particle size distribution in a multi-zone circulating fluidized bed polymerization reactor

PARTICUOLOGY 2024年第10期93卷 291-299页

作者： Hadadiyan, Mohammadhossein Mostou, Navid Marandi, Reza Univ Tehran Coll Engn Proc Design & Simulat Res Ctr Sch Chem Engn POB 11155-4563 Tehran Iran Natl Petrochem Co Petrochem Res & Technol Co Polymer Res Grp POB 14358-84711 Tehran Iran

This research focuses on modeling a multi-zone circulating reactor (MZCR) in the polypropylene production process. In these reactors, designed for polyolefin production, small catalyst particles (20-300 mm) initiate polymerization in the presence of monomer gas. The reactor consists of two main regions: the riser and the downer. The riser operates in the fast fluidization and the downer is in the moving bed regime. Employing the two-fluid model with the Eulerian-Eulerian approach, the dynamics of both solid and gas phases were modeled by applying Newton's laws of motion and assuming spherical particles. The population balance of particles within the reactor was also coupled with the equations of motion. The simultaneous solution of these equations provides valuable insights into particle and fluid behavior, revealing trends such as the growth of polymer particles. Furthermore, the impact of various operating conditions was explored. This study also examined the effects of design parameters (gas inlet velocity, average inlet diameter, and temperature) on the system performance. For instance, it was shown that in the case where the solid circulation flux is 30 kg/(m2 2 s) the velocity of particles in the bed increases from 0.4 at the inlet to 1.1 m/s in the fully developed zone, when it is 43 kg/(m2 2 s) the velocity of particles increases from 0.3 to 1.4 m/s, and when it is 55 kg/(m2 2 s), it is increased from 0.22 to 1.5 m/s. Additionally, trends in particle size distribution based on temperature adjustments were revealed. This study showed that higher temperatures accelerate the polymerization reaction rate, promoting faster growth kinetics and the formation of larger particles. (c) 2024 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

关键词： Fluidization Polymerization Gas-solid flow Multi-zone circulating reactor (MZCR) CFD-PBM Two-fluid model GAS-PHASE POLYMERIZATION CFD SIMULATION 2-FLUID MODEL HYDRODYNAMICS FLOW DYNAMICS SOLIDS PBM

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Multiple Functions of Nuclear DNA Helicase Ⅱ (RNA Helicase A) in Nucleic Acid Metabolism

引用

Acta Biochimica et Biophysica Sinica 2004年第3期36卷 177-183页

作者： Frank GROSSE Department of Biochemistry Institute of Molecular Biotechnology pob 100 813 D-07708 Jena Germany

Nuclear DNA helicase II (NDH II), or RNA helicase A (RHA), was initially discovered in mammals by conventional protein purification methods. Molecular cloning identified apparent sequence ho- mologies between NDH II and a Drosophila protein named maleless (MLE), the latter being essential for the Drosophila X-chromosome dosage compensation. Increasing amounts of evidence suggest that NDH II is involved in multiple aspects of cellular and viral DNA and RNA metabolism. Moreover the functions of NDH II may have potential clinical implications related to viral infection, autoimmune diseases, or even tumorigenesis.

关键词： DNA and RNA helicase maleless (MLE) X-chromosome dosage compensation dsRBD RGG-box transcription RNA processing RNA transport actin nucleolus SLE (systemic lupus erythematosus) virus

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Magnetic,dielectric and electrical modulus of Ce^(3+) doped cobalt-magnesium ferrite nanoparticles

引用

Journal of Rare Earths 2024年第2期42卷 373-382,I0005页

作者： N.M.Basfer Hanaa Almaghamsi Department of Physics Umm AL-Qura UniversityMakkahSaudi Arabia Physics Department College of Science and ArtKing Abdulaziz UniversityPOB344Rabigh291Saudi Arabi

In this work,the magnetic,dielectric properties and electric modulus of Ce^(3+) substituted cobaltmagnesium(Co_(0.7)Mg_(0.3)Ce_(x)Fe_(2-x)O_4)(labeled as CMCF) ferrite nanoparticles were investigated in *** magnetization decreases from 50.05 to 34.87 emu/g for further substituting Ce^(3+) ***,coercivity increases from 738.22 Gs for the CMCFO sample to 912.10 Gs for the CMCF2 sample,then decreases monotonically to 762.1 Gs for the CMCF5 *** cerium content and particle size play important roles in controlling the magnetization and coercivity of the CMCF *** CMCF nanoferrites are suitable for microwave applications since their high-frequency response ranges from 7.72 to 11.07 *** CMCF nanoferrites' dielectric parameter dispersion exhibits normal *** pristine Co-Mg nanoferrite only has ε' value of 28.25,but the nanoferrite MCMF2 has ε' value of365.03,with an enhancing ratio of 1192%.The conduction mechanism of the MCMF nanoferrites was determined by fitting the σ_(ac) results via the Jonscher power *** 653 K,large polaron tunnelling is thought to be responsible for this conduction process,which is followed by electron barrier hopping at higher ***-Cole diagrams at different temperatures,assuring the contributions of the grains and their boundaries at lower temperatures(653 K) and only the grains at higher *** on our results,the CMCF nanoferrites hold magnetic and semiconducting nature,which can be used in magnetic devices and dielectrics in lower-frequencies or conductors in higher-frequencies.

关键词： Nanoferrites Rare earth ions Magnetic properties Dielectric parameters Impedance spectroscopy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A hybrid machine-learning model for solar irradiance forecasting

引用

CLEAN ENERGY 2024年第1期8卷 100-110页

作者： Almarzooqi, Ameera M. Maalouf, Maher El-Fouly, Tarek H. M. Katzourakis, Vasileios E. El Moursi, Mohamed S. Chrysikopoulos, Constantinos, V Khalifa Univ Dept Ind & Syst Engn POB 127788 Abu Dhabi U Arab Emirates Khalifa Univ Abu Dhabi Elect Engn & Comp Sci Dept Abu Dhabi U Arab Emirates Khalifa Univ Dept Civil Infrastruct & Environm Engn POB 127788 Abu Dhabi U Arab Emirates Tech Univ Crete Sch Chem & Environm Engn Khania 73100 Greece

Nowcasting and forecasting solar irradiance are vital for the optimal prediction of grid-connected solar photovoltaic (PV) power plants. These plants face operational challenges and scheduling dispatch difficulties due to the fluctuating nature of their power output. As the generation capacity within the electric grid increases, accurately predicting this output becomes increasingly essential, especially given the random and non-linear characteristics of solar irradiance under variable weather conditions. This study presents a novel prediction method for solar irradiance, which is directly in correlation with PV power output, targeting both short-term and medium-term forecast horizons. Our proposed hybrid framework employs a fast trainable statistical learning technique based on the truncated-regularized kernel ridge regression model. The proposed method excels in forecasting solar irradiance, especially during highly intermittent weather periods. A key strength of our model is the incorporation of multiple historical weather parameters as inputs to generate accurate predictions of future solar irradiance values in its scalable framework. We evaluated the performance of our model using data sets from both cloudy and sunny days in Seattle and Medford, USA and compared it against three forecasting models: persistence, modified 24-hour persistence and least squares. Based on three widely accepted statistical performance metrics (root mean squared error, mean absolute error and coefficient of determination), our hybrid model demonstrated superior predictive accuracy in varying weather conditions and forecast horizons. A novel prediction method for solar irradiance, targeting both short-term and medium-term forecast horizons, is proposed to improve PV power production. The hybrid framework employs a fast trainable statistical learning technique based on the truncated-regularized kernel ridge regression model. Graphical Abstract

关键词： solar power generation kernel ridge regression hybrid model forecasting BATTERY ENERGY-STORAGE POWER PV RADIATION PREDICTION CELLS

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tilted global solar irradiance in Bahrain: an experimental study

引用

CLEAN ENERGY 2024年第2期8卷 27-34页

作者： Vasilikos, N. Georgantopoulou, C. Alajaimi, H. Almajed, S. H. Ahmed, M. Mathioulakis, D. Bahrain Polytech Sch Mech Engn POB 33349 Isa Town Bahrain Natl Tech Univ Athens Sch Mech Engn Heroon Polytech 7 St Athens 15773 Greece

In the present work, tilted global solar irradiance data are presented and analysed, measured for a period of 1 year on the campus of Bahrain Polytechnic, Kingdom of Bahrain, from both a fixed photovoltaic panel and a moving one via a two-axis solar tracker. The fixed panel faces south with an angle of 26 degrees with respect to the horizontal, coinciding with the local geographical latitude. The second panel is moved by two motors, controlled by a global positioning system and suitable software so that the Sun's rays are perpendicular to the panel surface. A pyranometer is installed on each panel, recording the tilted global solar irradiance, stored by using a data logger. The analysis of the data obtained shows a 33% solar energy gain on an annual basis for the moving panel (2780 versus 2088 kWh/m2 on the fixed panel). More importantly, in June, when the energy demand in Bahrain is elevated due to the increased residential cooling loads, the solar energy received by the moving panel is 54.7% higher compared with that of the fixed panel. On a percentage basis, the increase in solar energy from the moving panel is profound in the early morning and late evening hours. Moreover, the reduction in the solar energy received by the fixed panel from May to June does not appear in the moving panel because of the adjustable orientation of the latter. Throughout the year, the mean daily solar power varies between 0.37 and 0.56 kW/m2 for the fixed panel, and 0.45 and 0.70 kW/m2 for the moving panel. In winter, solar energy fluctuations are elevated due to erratic weather conditions that present a peak standard deviation of 28% of the corresponding mean. The data presented are useful for potential solar investments in Gulf countries. Tilted global solar irradiance data are measured and analysed for a period of 1 year on the campus of Bahrain Polytechnic, Kingdom of Bahrain, from both a fixed photovoltaic panel and a moving one via a two-axis solar tracker. Graphical Abstract

关键词： tilted solar irradiance renewable energy solar tracking photovoltaic Gulf Cooperation Council Countries SUN TRACKING ENERGY SYSTEMS PANELS WORLD

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Local MFS Matrix Decomposition Algorithms for Elliptic BVPs in Annuli

引用

NUMERICAL MATHEMATICS-THEORY METHODS AND APPLICATIONS 2024年第1期17卷 93-120页

作者： Chen, C. S. Karageorghis, Andreas Lei, Min Univ Southern Mississippi Sch Math & Nat Sci Hattiesburg MS 39406 USA Univ Cyprus Dept Math & Stat POB 20537 CY-1678 Nicosia Cyprus Taiyuan Univ Technol Coll Math Taiyuan 030024 Peoples R China

We apply the local method of fundamental solutions (LMFS) to boundary value problems (BVPs) for the Laplace and homogeneous biharmonic equations in annuli. By appropriately choosing the collocation points, the LMFS discretization yields sparse block circulant system matrices. As a result, matrix decomposition algorithms (MDAs) and fast Fourier transforms (FFTs) can be used for the solution of the systems resulting in considerable savings in both computational time and storage requirements. The accuracy of the method and its ability to solve large scale problems are demonstrated by applying it to several numerical experiments.

关键词： Local method of fundamental solutions Poisson equation biharmonic equation matrix decomposition algorithms fast Fourier transforms BOUNDARY-VALUE-PROBLEMS FUNDAMENTAL-SOLUTIONS RBF ALGORITHMS

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A semiclassical perspective on nuclear chirality

引用

Frontiers of physics 2024年第2期19卷 39-52页

作者： Radu Budaca “Horia Hulubei”National Institute for R&D in Physics and Nuclear Engineering Str.Reactorului 30RO-077125POB-MG6 Bucharest-MǎgureleRomania Academy of Romanian Scientists Splaiul Independenţei 54050044BucharestRomania

The application of the semiclassical description to a particle-core system with imbued chiral symmetry is *** classical features of the chiral geometry in atomic nuclei and the associated dynamics are investigated for various core deformations and single-particle *** dynamical characteristics are identified in specific angular momentum ranges,triaxiality and alignment *** observables will be extracted from the classical picture for a quantitative description of experimental data provided as numerical examples of the model’s performance.

关键词： chiral symmetry triaxial nuclei semiclassical description

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Exploring public perception and willingness to pay for a renewable source of energy: evidence from an emerging economy of renewable-energy development

引用

CLEAN ENERGY 2024年第2期8卷 177-188页

作者： Bashir, Mohammed J. K. Abdelhak, Senadjki Salah, Wael A. Abuhelwa, Mai Cent Queensland Univ Sch Engn & Technol 120 Spencer St Melbourne Qld 3000 Australia Univ Tunku Abdul Rahman Fac Business & Finance Kampar Perak Malaysia Palestine Tech Univ Kadoorie Coll Engn & Technol Dept Elect Engn POB 7 Yafa St Tulkarm Palestine Univ Missouri Dept Elect Engn & Comp Sci Columbia MO 65211 USA

The study focuses on the transition from conventional energy sources to sustainable renewable energy (RE) in Palestine, particularly in the West Bank and Gaza Strip. The research aims to understand the relationship between key factors and residents' willingness to invest in the RE sector, with a specific focus on the impact of education. Using the unified theory of acceptance and use of technology, the study analyzes data from 400 residents through a questionnaire and employs ordinary least-squares regression analysis with Eviews 12. The key findings indicate that residents' inclination to invest in RE is significantly influenced by factors such as resource availability, knowledge level and power outages. Moreover, the study suggests that educated residents are more likely to invest in RE when factors such as knowledge, effort expectation, enabling conditions and resource availability are relatively high. The conclusion emphasizes the importance of policymakers' allocating sufficient funds to research and development to promote technological innovation in RE sources, thereby enhancing the population's energy efficiency. The study focuses on the transition from conventional energy to sustainable renewable energy in Palestine, particularly in the West Bank and Gaza Strip, to understand the relationship between key factors and residents' willingness to invest in the RE sector, with a specific focus on the impact of education. Graphical Abstract

关键词： renewable energy technology energy security public perceptions sustainable development UNIFIED THEORY RURAL-AREAS TECHNOLOGY ACCEPTANCE DETERMINANTS INTENTION RELIABILITY SERVICES SYSTEM ERRORS

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Comparisons and optimization of two absorption chiller types by considering heat transfer area, exergy and economy as single-objective functions

引用

CLEAN ENERGY 2024年第1期8卷 55-65页

作者： Qiu, Yida Wang, Jingkun Han, Jing Chen, Yuzhu Wang, Jun Lund, Peter D. Univ Liverpool Management Sch Liverpool L693BX Lancs England Power China Huadong Engn Corp Ltd 201 Gaojiao Rd Hangzhou 311122 Peoples R China Southeast Univ Key Lab Solar Energy Sci & Technol Jiangsu Prov 2 Si Pai Lou Nanjing 210096 Peoples R China Aalto Univ Sch Sci POB 15100 FI-00076 Espoo Finland

Absorption cooling technology is an environmentally friendly method to generate continuous chilled water making use of multiple thermal sources, such as waste heat and renewable thermal energy. In this study, two absorption chillers (nominal capacity of 400 kW) with series and parallel connections are evaluated. To research the ideal configuration of chillers after thermodynamic analysis, the structures of the chillers are optimized using the particle swarm optimization algorithm by considering the heat transfer area (HTA), exergy efficiency and total annual cost as single-objective functions. The impact of temperature differences between external and internal flows, heat exchanger efficiencies and the solution allocation ratio is estimated. The optimized HTA, coefficient of performance, exergy efficiency and total annual cost are 149.0 m2, 1.56, 29.44% and $229 119 for the series-connected chiller, and 146.7 m2, 1.59, 31.45% and $234 562 for the parallel-connected type, respectively. Under the lowest HTA condition, compared with the reference simulation results, the energy and exergy performances are improved, while the annual total cost is higher. The annual total cost is highest when maximizing the exergy efficiency, which is attributed to the increase in the HTA. The operating cost accounts for 27.42% (series type) and 26.54% (parallel type) when the annual cost is the lowest. Two absorption chillers with series and parallel connections are evaluated using a thermodynamic analysis. The chiller structures are optimized using the particle swarm optimization algorithm by considering the heat transfer area, exergy efficiency and total annual cost as single-objective functions. Graphical Abstract

关键词： absorption chiller series/parallel-connected temperature difference parameters solution allocation ratio REFRIGERATION SYSTEMS COOLING SYSTEM MULTIOBJECTIVE OPTIMIZATION PERFORMANCE ANALYSIS CLIMATE ZONES SERIES PARALLEL ENERGY CONSUMPTION REDUCE

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Phytoremediation capacity of the hyperaccumulator Solanum nigrum *** Solanum lycopersicum *** at the flowering stage in cadmium-polluted soil

引用

Pedosphere 2024年第3期34卷 676-680页

作者： Jibao JIA Huiping DAI Shuhe WEI Lidia SKUZA Jianming XUE Rong LI Quan SUN School of Agriculture Ningxia UniversityYinchuan 750021(China) School of Biological Science and Engineering Shaanxi University of TechnologyHanzhong 723001(China) Key Laboratory of Pollution Ecology and Environment Engineering Institute of Applied EcologyChinese Academy of SciencesShenyang 110016(China) Institute of Biology Centre for Molecular Biology and BiotechnologyUniversity of SzczecinSzczecin 71-415(Poland) New Zealand Forest Research Institute(Scion) POB 29237Christchurch 8440(New Zealand)

Dear Editor,Remediation of cadmium(Cd)-contaminated soil is a popular topic in global environmental *** using hyperaccumulators or certain plants to accumulate and remove Cd from polluted soils is a promising *** et al.(2005)first described Solanum nigrum *** a Cd ***,various aspects of ***,including the protective effects on proline,physiological and biochemical responses,earthworms,arbuscular mycorrhizal fungi,and fertilizers and the intercropping with Solanum photeinocarpum,have been extensively studied(Xu et al.,2009;Khan et al.,2014;Wang et al.,2015;Tang et al.,2017;Yang et al.,2019).

关键词： soil cultivar cadmium

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：