检索结果-内蒙古大学图书馆

Experimental investigation on the effect of the Fused Deposition Modeling parameters on the processing of Polyether Ether Ketone

引用

Journal of Materials Research and Technology 2025年 36卷 8007-8021页

作者： Erica Billè Marina Franulović Alessandro Gambitta David Liović Alfredo Rondinella Federico Scalzo Marco Sortino Giovanni Totis Emanuele Vaglio Polytechnic Department of Engineering and Architecture University of Udine Via delle Scienze 206 Udine 33100 Italy University of Rijeka Faculty of Engineering Vukovarska 58 Rijeka 51000 Croatia Elettra-Sincrotrone Trieste Area Science Park Basovizza Trieste 34149 Italy

The use of Fused Deposition Modeling to produce high-performance polyether ether ketone is steadily increasing. However, the limited availability of in-depth studies on the process hampers its potential for industrial and scientific applications. This study investigates how nozzle temperature, nozzle speed, and layer thickness influence crucial product properties, including surface roughness, dimensional accuracy, and mechanical behavior, by means of Confocal and Scanning Electron Microscopy, X-ray Micro-Computed Tomography, Fourier-Transform Infrared Spectroscopy, Energy-Dispersive X-ray Spectroscopy, tensile and hardness tests. Selected samples were further analyzed in exceptional detail by synchrotron radiation, while degassing behavior in Ultra-High Vacuum conditions was explored for optimal configurations. The results highlight the critical influence of process parameters on the final properties of FDM-printed PEEK parts. Nozzle temperature proved to be the most significant factor in improving both mechanical performance and surface finish, while nozzle speed predominantly affected dimensional accuracy. Layer thickness had a secondary effect, mainly influencing surface roughness and contributing to internal defects and variability in mechanical properties. The combination of parameters that yielded the most balanced performance was identified as a nozzle temperature of 420 °C, nozzle speed of 40 mm/s, and layer thickness of 0.1 mm. Across all tested configurations, the maximum Ultimate Tensile Strength achieved was 84 MPa, while the highest recorded part density reached 99.8%. These outcomes enabled the successful manufacturing of components suitable for ultra-high vacuum environments. The process was validated through the fabrication of a benchmark part with complex geometries, demonstrating the capability of FDM to produce high-precision, high-performance components.

关键词： Additive manufacturing Fused deposition modeling PEEK Process parameters optimization

来源：评论

学校读者我要写书评

暂无评论

Systematic approach to sustainable urban development: reviewing challenges of informal settlements and peri-urban growth in sub-Sahara Africa

引用

Urban, Planning and Transport Research 2025年第1期13卷

作者： Olaniran, Temitope Olufolahan Aule, Thomas Terna Department of Architecture Faculty of Engineering and the Built Environment Durban University of Technology Durban South Africa Department of Architectural Technology Federal Polytechnic Kaura-Namoda Nigeria

This paper systematically reviews scholarly literature on informal settlements in peri-urban areas, with a focus on the interplay of socio-economic, environmental, governance, and built environment factors contributing to their emergence and persistence. Drawing on 10 studies across predominantly sub-Saharan African contexts, the review analyses core variables, methodological designs, theoretical frameworks, and geographical patterns. Findings reveal that socio-economic exclusion, weak institutional coordination, and dual land governance systems significantly drive informality. Customary and religious institutions often mediate land access and conflict resolution, compensating for gaps in statutory urban planning systems. Environmental risks such as poor sanitation, contaminated water sources, and inadequate waste management remain under-addressed. Notably, the review identifies a critical gap in existing research: the limited application of architectural, spatial planning, and design-based strategies for upgrading and integrating informal settlements into the formal urban fabric. Although incremental upgrading has been proposed as a viable intervention, few studies offer context-sensitive, design-led frameworks for implementation. This study calls for interdisciplinary, solution-oriented approaches that blend policy, governance, and architectural insights to ensure inclusive, sustainable urban development. Recommendations emphasise participatory upgrading, improved service delivery, and legal recognition of informal settlements. The findings are relevant for policymakers, planners, designers, and researchers committed to addressing urban informality in sub-Sahara Africa and beyond. © 2025 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

关键词： Bibliometric analysis informal settlements interdisciplinary planning Peri-urban areas sustainable urban development systematic review

来源：评论

学校读者我要写书评

暂无评论

Digital twin driven thermal error control of linear axis for face gear grinding machine tool 20

Digital twin driven thermal error control of linear axis for...

引用

20th CIRP Conference on Modeling of Machining Operations in Mons, CIRP CMMO 2025

作者： Li, Mingming Ma, Chi Liu, Jialan Totis, Giovanni Academy of Aerospace Solid Propulsion Technology Xi'an710025 China College of Mechanical and Vehicle Engineering Chongqing University Chongqing400044 China State Key Laboratory of Mechanical Transmission for Advanced Equipment Chongqing University Chongqing400044 China School of Construction Machinery Chang'An University Xi'an710064 China Polytechnic Department of Engineering and Architecture University of Udine Via delle Scienze 206 Udine33100 Italy

The face gear transmission system offers advantages such as high interchangeability, strong load capacity, and effective power distribution, making it suitable for defense applications. The machining accuracy of the face gear grinding machine tool is significantly affected by the geometric and thermal errors, leading to a reduced geometric precision of the machined face gear. The real-time performance and robustness of the geometric and thermal error compensation system are the key to realize the thermal error control. So far, the real-time performance of compensation system is weak, and the robustness is poor. To address the above challenges, the effect of the temperature changes on positioning accuracy is studied. Then the thermal error prediction model is established based on the error mechanism for the linear axis of face gear grinding machine tool. Finally, the digital twin-driven thermal error control system is developed. The thermal error model is embedded into the digital twin-driven geometric and thermal error control system to realize the thermal error compensation of linear axis for face gear grinding machine tool. With the implementation of the digital twin-driven thermal error control system, the left tooth surface error decreased from 21.8 μm to 5.9 μm, and the right tooth surface error decreased from 22.9 μm to 5.7 μm, confirming the effectiveness of the proposed method. © 2025 The Author(s).

关键词： Grinding machines

来源：评论

学校读者我要写书评

暂无评论

Enhancing mechanical strength and reducing drying shrinkage in high-volume fly ash mortar: Synergistic effects of steel fibers and nano-SiO 2

引用

Journal of Materials Research and Technology 2025年 36卷 7351-7360页

作者： Junliang Zhao Jingjing Huang Zhongkun Wang Dongyan Wu Gengying Li College of Civil Engineering and Architecture Wenzhou University Wenzhou 325035 Zhejiang China Key Laboratory of Engineering and Technology for Soft Soil Foundation and Tideland Reclamation of Zhejiang Province Wenzhou 325035 China School of Civil Engineering & Architecture Wenzhou Polytechnic Wenzhou 325035 China Department of Civil Engineering and Smart Cities Shantou University Shantou 515063 Guangdong China College of Water Conservancy and Civil Engineering South China Agricultural University Guangzhou 510642 China

This study investigated the effects of steel fibers and nano-silica dioxide (nano-SiO 2 ) on the fluidity, capillary water absorption, mechanical properties, and drying shrinkage of mortar when 50 % of the cement was replaced by fly ash. The mechanisms by which steel fibers and nano-SiO 2 influence high-volume fly ash mortar were discussed based on macroscopic tests and microscopic structural analysis. The results show that while nano-SiO 2 and steel fibers had negligible effects on the fluidity of fly ash mortar, they significantly enhanced its mechanical properties. When the steel fiber content was 1.0 % and the nano-SiO 2 content was 2.0 %, the modified mortar exhibited increases in flexural and compressive strength by 86.4 % and 53.7 %, respectively, compared to the unmodified mortar at 28 days of age. Additionally, the incorporation of nano-SiO 2 and steel fibers significantly reduced the capillary water absorption and drying shrinkage of the mortar. The capillary absorption rate of the 1.0 % steel fibers and 2.5 % nano-SiO 2 composite mortar decreases 67.8 % compared to the fly ash mortar. At 90 days of age, the drying shrinkage of the modified mortar containing 1.0 % steel fibers and 2.5 % nano-SiO 2 was reduced by 44.4 % compared to the unmodified mortar. Microstructural characterization through scanning electron microscopy (SEM) and X-ray diffraction (XRD) demonstrated that nano-SiO 2 incorporation enhanced the hydration of both fly ash and cement, leading to a significant reduction in unhydrated fly ash particles. Furthermore, mercury intrusion porosimetry (MIP) tests demonstrated that the addition of nano-SiO 2 and steel fibers markedly decreased the average and median pore sizes in the mortar, resulting in a more optimized pore structure distribution.

关键词： High-volume fly ash mortar Nano-SiO 2 Steel fibers Fluidity Mechanical properties Drying shrinkage

来源：评论

学校读者我要写书评

暂无评论

Low temperature plasma carburizing of additive manufactured 316 L steel: the effect of treatment time on tribological behavior

引用

Journal of Materials Research and Technology 2025年 36卷 9962-9977页

作者： S. Kaciulis A. Lanzutti A. Mezzi R. Montanari A. Palombi N. Picco E. Vaglio A. Varone C. Verona ISMN-CNR P.O. Box 10 Monterotondo Stazione 00015 Rome Italy Polytechnic Department of Engineering and Architecture University of Udine Via delle Scienze 208 33100 Udine Italy Department of Industrial Engineering University of Rome Tor Vergata Via del Politecnico 1 00133 Roma Italy

A low temperature (∼475 °C) plasma assisted carburizing treatment has been employed to improve the tribological behavior of 316 L steel manufactured by Laser Powder Bed Fusion (L-PBF). The treatments have been carried out in a carburizing atmosphere consisting of 2.5 % CH 4 + 97.5 % H 2 with increasing treatment time, from 30 to 120 min. For all the treatments, the result is the formation of a layer of expanded austenite (S-phase), responsible for surface hardening. If the treatment time is longer than 90 min, an overlayer of Diamond-Like Carbon (DLC) has been observed on the surface. Wear tests in pin-on-flat (POF) mode at room temperature with applied loads of 10 N and 20 N have been employed to identify the treatment conditions leading to the optimal wear resistance. The wear resistance of all the samples resulted to be greater than the one of the not treated material, but it is negatively affected by the formation of the DLC overlayer. In fact, due to its hardness and brittleness, it detaches from the surface during the wear tests and contributes to increasing the wear rate. The best tradeoff is a 90 min treatment leading to the formation of a ∼25 μm thick S-phase layer without the deposition of DLC. In this treatment condition, the wear rate is about 20 times lower than the one of the not treated 316L steel produced by L-PBF and tested in the same conditions.

关键词： 316 L steel Laser powder bed fusion Plasma assisted low temperature carburizing Wear Microstructure Surface hardening

来源：评论

学校读者我要写书评

暂无评论

Influencing factors of metabolic rates and their implications in thermal comfort research

引用

Energy and Buildings 2025年 339卷

作者： Zhao, Shengkai Yang, Liu Gao, Siru Yan, Haiyan Zhang, Hui Arens, Edward Liu, Shichao Zhai, Yongchao School of Architectural and Artistic Design Henan Polytechnic University Henan Jiaozuo454000 China State Key Laboratory of Green Building Xi'an University of Architecture and Technology Shaanxi Xi'an710055 China College of Architecture Xi'an University of Architecture and Technology Shaanxi Xi'an710055 China Center for the Built Environment UC Berkeley BerkeleyCA94720 United States Department of Civil Environmental Architectural Engineering Worcester Polytechnic Institute WorcesterMA01609 United States

Metabolic rate is an important physiological factor affecting thermal sensation and comfort. The metabolic rate values provided by existing standards do not consider factors such as temperature, sex, age, BMI, and population differences, which may lead to deviations in the prediction of human thermal sensation. Therefore, accurate metabolic rate measurement and calculation have become a key issue in thermal comfort research. Based on the metabolic rate data measured by our research group and relevant literature, this study systematically explored the methods of obtaining metabolic rate, its influencing factors, dynamic characteristics, and its impact on thermal comfort. Firstly, we summarized and analyzed the methods of obtaining metabolic rate values, pointing out the measurement accuracy, cost, and applicability of different methods. Secondly, we quantified the factors influencing metabolic rate and found that environmental temperature, sex, age, BMI, and population differences (Asian vs. Western) all have an impact on metabolic rate. Among these factors, metabolic rate is lowest under thermal neutrality, and deviating from the neutral temperature leads to an increase in metabolic rate;males generally have a higher metabolic rate than females, but the difference is only significant under low temperature and high activity conditions;people with low BMI have a higher metabolic rate, but the test results did not reach a significant level. Furthermore, based on measured data, we described the dynamic changes in the metabolic rate of building users when switching between different activity levels and proposed a predictive equation for dynamic real-time metabolic rate values. There is a significant correlation between metabolic rate and CO2 production rate, and indoor CO2 production rate can be estimated based on age, sex, and metabolic rate. Finally, we explored the impact of metabolic rate on thermal comfort and found that an increase in metabolic rate significantly r

关键词： Age CO2 generation rate Heart rate Metabolic rate Sex Thermal comfort

来源：评论

学校读者我要写书评

暂无评论

On the truth of integral and differential constitutive forms in strain-driven nonlocal theories with bi-Helmholtz kernels for nanobeam analysis

引用

Thin-Walled Structures 2025年 214卷

作者： Song, Z.W. Lai, S.K. Lim, C.W. Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Kowloon Hong Kong China The Hong Kong Polytechnic University Shenzhen Research Institute Nanshan Shenzhen China Department of Architecture and Civil Engineering City University of Hong Kong Kowloon Hong Kong China

Considering various strain-driven nonlocal theories that apply bi-Helmholtz kernels, prior studies pointed out the ill-posedness of differential forms (DFs). However, a perplexing question persists regarding the clear demonstration of true consistencies of integral forms (IFs). In addition, the role of constitutive boundary conditions (CBCs) in IFs is not well understood. To address these problems, we re-visit the existence of CBCs and evaluate the consistencies of both DFs and IFs. In this study, we conduct a comprehensive analysis for Eringen's nonlocal theory, Eringen's local/nonlocal theory, nonlocal strain-gradient theory, mixture nonlocal strain-gradient theory and local/nonlocal strain-gradient theory with bi-Helmholtz kernels. Our findings indicate that both IFs and DFs in strain-driven pure and mixed nonlocal theories are indeed ill-posed due to overabundance of boundary conditions. Conversely, IFs and DFs in strain-driven local/nonlocal theories, where classical and higher-order terms in IFs are represented in mixed local/nonlocal forms, are well-posed. Furthermore, for well-posed systems, CBCs can be directly derived from IFs and are essential for both IFs and DFs, being explicit in DFs but implicit in IFs. The presence of CBCs is closely tied to IFs and kernels, but is unrelated to DFs. Result verification is provided through illustrative examples of nanobeam analysis. The research presented here is the first attempt to provide theoretical proofs to illustrate the true consistencies of strain-driven nonlocal theories from both differential and integral perspectives to bridge the theoretical gap. © 2025 Elsevier Ltd

关键词： Boundary conditions

来源：评论

学校读者我要写书评

暂无评论

FLOW36: A spectral solver for phase-field based multiphase turbulence simulations on heterogeneous computing architectures

引用

Computer Physics Communications 2025年 313卷

作者： Roccon, Alessio Soligo, Giovanni Soldati, Alfredo Institute of Fluid Mechanics and Heat Transfer TU-Wien Vienna1060 Austria Polytechnic Department of Engineering and Architecture University of Udine Udine33100 Italy Complex Fluids and Flows Unit OIST Okinawa904-0495 Japan

We present FLOW36, a GPU-ready solver for interface-resolved simulations of multiphase turbulence. The simulation framework relies on the coupling of direct numerical simulation of turbulence, used to describe the flow field, with a phase-field method, used to describe the shape and deformation of a deformable interface and the presence of surfactants. An additional transport equation for a passive scalar can be solved to describe heat transfer in multiphase turbulence. The governing equations are solved in a cuboid domain bounded by two walls along the wall-normal direction where no-slip, free-slip or fixed/moving wall boundary conditions can be applied, while periodicity is applied along the streamwise and spanwise directions. The numerical method relies on a pseudo-spectral approach where Fourier series (periodic directions) and Chebyshev polynomials (wall-normal direction) are used to discretize the governing equations in space. Equations are advanced in time using an implicit-explicit scheme. From a computational perspective, FLOW36 relies on a multilevel parallelism. The first level of parallelism relies on the message-passing interface (MPI). A second level of parallelism uses OpenACC directives and cuFFT libraries;this second level is used to accelerate the code execution when heterogeneous computing infrastructures are targeted. In this work, we present the numerical method and we discuss the main implementation strategies, with particular reference to the MPI and OpenACC directives and code portability, performance and maintenance strategies. FLOW36 is released open source under the GPLv3 license. Program summary: Program Title: FLOW36 CPC Library link to program files: https://***/10.17632/ygcn7dsb9k.1 Developer's repository link: https://***/MultiphaseFlowLab/FLOW36 Licensing provisions: GPLv3 License Programming language: Modern Fortran Nature of problem: Solving the three-dimensional incompressible Navier–Stokes equations in a Cartesian doma

关键词： Navier Stokes equations

来源：评论

学校读者我要写书评

暂无评论

Analyzing factors influencing defect-based conditions for sewer pipes using Bayesian networks

引用

Reliability engineering and System Safety 2025年 262卷

作者： Ma, Shihui Zayed, Tarek Xing, Jiduo Ren, Zhihao Department of Building and Real Estate Faculty of Construction and Environment The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong Department of Architecture and Civil Engineering City University of Hong Kong 83 Tat Chee Avenue Kowloon Tong Hong Kong

The failure and condition of sewer pipes are usually influenced by various uncertainties and factors. Therefore, it is vital to evaluate the defect-based condition of sewer pipes for maintenance and failure prevention. In contrast to relying on the existing domain knowledge, this paper proposes a data-driven Bayesian network (BN) model to analyze the impacts of different influence factors (IFs) on the sewer pipes’ defect-based condition based on the developed database about the Hong Kong sewer network. Specifically, fourteen IFs are collected to develop a multi-source integrated database that incorporates pipe physical, environment, and climate-related factors. Then, the structure of the BN model is learned by Bayesian searching algorithm, and the reliability of the proposed model is evaluated using sensitivity analysis methods. Moreover, special scenarios are assumed to explore possible configurations of IFs. The results reveal that age, diameter, population and soil type are the top four IFs affecting the condition of sewer pipes, among which pipes with some characteristics need to be closely monitored, such as pipe age greater than 50 years, diameter less than 200 mm, location with a population density less than 15,000, and location in fill or granitic rocks. This paper improves sewer pipe management by integrating a comprehensive database and enabling reliable pipe condition inferences. The insights provide practical suggestions for the sewer pipe layout, risk analysis, and maintenance strategy formulation. It is a precious tool for authorities to enhance the safety and efficiency of sewer system management. © 2025 Elsevier Ltd

关键词： Risk assessment

来源：评论

学校读者我要写书评

暂无评论

Wind load interference mechanisms for inclined angle and gap spacing of photovoltaic panels

引用

Physics of Fluids 2025年第2期37卷

作者： Liu, Tingting Mi, Hanning Ai, Yifeng Zhang, Hongfu Zhou, Daocheng Zhou, Lei School of Civil Engineering and Transportation Northeast Forestry University Heilongjiang Province Harbin China China Electric Power Research Institute Beijing China Department of Architecture and Civil Engineering City University of Hong Kong Hong Kong Department of Mechanical Engineering The Hong Kong Polytechnic University Hong Kong School of Civil Engineering Central South University Hunan Province Changsha China

This study aims to explore wind load interference effects on tandem photovoltaic (PV) panels, focusing on inclined angles ( α ) and gaps ( X / L ). Conventional models often struggle to capture nonlinear airflow dynamics that drive these interference effects. To address this limitation, the research introduces a novel approach to analyze the complex spatiotemporal evolution of interference phenomena in PV panels. A quantitative analysis was conducted using the high-order Koopman Mode Decomposition (HOKMD) method. This method integrates high-order nonlinear components, enabling precise identification of dynamic modes and coherent structures. This study evaluates the synchronous vorticity and pressure fields, fluid forces, and power spectra of PV panels under varying α and X / L . The results demonstrate that for α > 25 ° and X / L 2.0 , significant shielding effects are observed on the downstream panel. It revealed two dominant dynamic modes, providing new insights into airflow patterns and vortex interactions that traditional linear models fail to capture. The application of HOKMD accurately captures the nonlinear characteristics of the flow around PV panels. The findings advance the understanding of airflow interactions in PV panels and provide valuable insights for optimizing PV design to improve structural stability and durability. © 2025 Author(s).

关键词： Vortex flow

来源：评论

学校读者我要写书评

暂无评论

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

请选择保存的检索档案：

请选择收藏分类：

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

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

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：