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Floating breakwater pontoon pilot cast with carbon textile reinforcement-based ultra high durability concrete: Materials development and testing, and implementation in the North Atlantic (Irelands west coast) 用碳纺织增强基超高耐久性混凝土浇筑的防波堤浮桥:北大西洋(爱尔兰西海岸)材料开发、测试和实施
Pub Date : 2023-01-01 DOI: 10.1051/matecconf/202337808001
C. Schroefl, M. Reichardt, V. Mechtcherine, P. Deegan
A floating unit with three pontoons made of epoxy-coated carbon textile reinforced, ultra-high durability concrete (ECF UHDC), mineral impregnated carbon fibre-reinforced UHDC (MCF UHDC) and, as references, steel-reinforced concretes has been designed and installed in the Northern Atlantic. While marine structures with steel reinforcement require large cover depths, which cause problems in size, cost, environmental friendliness and short service life, carbon textile reinforced concrete (TRC) cannot suffer from chloride-induced corrosion of a metal reinforcement. In the EU H2020 project “ReSHEALience” (rethinking coastal defence and green-energy service infrastructures through enhanced-durability highperformance cement-based materials), TRCs have been modified with functional admixtures from consortium partners. A mineral self-healing promoter and alumina nano-fibers have, among others, been implemented to boost high-performance concretes towards UHDCs. Resulting composite variants have been applied in a full-scale floating unit that has been launched in the harbor of Galway at the Irish West Coast in June 2020. Such a floating body is a representation of breakwaters installed to reduce wave impacts to the coast. Besides, TRC-based UHDC can be applied as strengthening and repair layer on concrete structures to enhance their service life in general.
一个由三个浮筒组成的浮动单元,由环氧涂层碳纤维纤维增强、超高耐久性混凝土(ECF UHDC)、矿物浸渍碳纤维增强UHDC (MCF UHDC)和参考钢筋混凝土组成,并在北大西洋进行了设计和安装。钢结构的海洋结构需要很大的覆盖深度,这造成了尺寸、成本、环保和使用寿命短的问题,而碳纺织钢筋混凝土(TRC)不能遭受金属钢筋的氯化物腐蚀。在欧盟H2020项目“ReSHEALience”(通过增强耐久性的高性能水泥基材料重新思考海防和绿色能源服务基础设施)中,TRCs已经使用来自财团合作伙伴的功能外加剂进行了修改。矿物自愈促进剂和氧化铝纳米纤维等已被用于促进高性能混凝土向超高密度混凝土发展。由此产生的复合变体已应用于2020年6月在爱尔兰西海岸戈尔韦港发射的全尺寸浮动装置。这样的浮体代表了防波堤的安装,以减少海浪对海岸的影响。此外,基于trc的UHDC可作为混凝土结构的加固和修复层,以提高混凝土结构的使用寿命。
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引用次数: 1
Tensile behavior of strain-hardening cementitious composites after self-healing based on a novel fiber-bridging model considering preloading and reloading 基于考虑预加载和再加载的新型纤维桥接模型的应变硬化胶凝复合材料自愈后拉伸行为
Pub Date : 2023-01-01 DOI: 10.1051/matecconf/202337809005
Yangqing Liu, Bo Wu, J. Qiu
The self-healing of strain-hardening cementitious composites (SHCCs) causes the recovery of the debonded fiber-to-matrix interface by the products of autogenous healing (mainly calcium carbonates). The recovery of chemical bond Gd has been detected in the reactive magnesia cement (RMC)-based SHCC (SHMC), and the recovery of frictional bond τ0 has been detected in both SHMCs and normal SHCCs. While these phenomena can significantly alter the fiber-bridging σ-w relationship in SHCCs, they have not been quantified in any existing analytical models. In this work, we present a new fiber-bridging model that captures the effect of self-healing of RMC-based SHCC. On the single-fiber level, the debonding and slip-hardening of the fiber-to-matrix interface induced by a tensile preloading as well as the recovery of the interface properties by self-healing are coherently quantified in a clear kinetic process. On the fiber-bridging level, the tensile stress vs. crack width curve is formed by summing individual fibers’ tensile load vs. displacement relationship. The modeling results can well capture the fiber-bridging behavior of the self-healed SHCC specimens. Further, a parametric study is conducted to investigate the tensile behavior of SHCC after self-healing. The effects of preloading levels, recovered τ0, and fiber strength are discussed.
应变硬化胶凝复合材料(SHCCs)的自愈作用是通过自愈产物(主要是碳酸钙)使脱落的纤维-基体界面恢复。在活性镁水泥(RMC)基SHCC (SHMC)中检测到化学键Gd的恢复,在SHMC和正常SHCC中检测到摩擦键τ0的恢复。虽然这些现象可以显著改变shcc中光纤桥接的σ-w关系,但在现有的分析模型中尚未对其进行量化。在这项工作中,我们提出了一种新的纤维桥接模型,该模型捕捉了基于rmc的SHCC的自愈效果。在单纤维水平上,拉伸预加载引起的纤维-基体界面的脱粘和滑移硬化以及自修复引起的界面性能的恢复在一个明确的动力学过程中得到了一致的量化。在纤维桥接水平上,拉应力与裂缝宽度曲线由单个纤维的拉伸载荷与位移关系求和而成。模拟结果较好地反映了自愈SHCC试件的纤维桥接行为。此外,进行了参数研究,以探讨自愈后SHCC的拉伸行为。讨论了预压水平、恢复τ0和纤维强度的影响。
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引用次数: 0
Research Status of Cathode Materials for Lithium Ion Batteries 锂离子电池正极材料研究现状
Pub Date : 2023-01-01 DOI: 10.1051/matecconf/202338201012
Zihao Lin
Thanks to the promotion of new energy vehicles, the industry of lithium-ion batteries has ushered in its booming period. The current industry of lithium ion batteries is in rapid development with great potential. Therefore, many researchers have turned to focus on lithium ion batteries to obtain better lithium ion batteries. In this paper, the literature review of cathode materials for lithium ion batteries is to be carried out from the following aspects, including the overview of lithium ion batteries, their basic performance indexes, and the classification and preparation methods of cathode materials. Besides, the present situation and modification strategies of cathode materials for lithium ion batteries will be further analyzed, so as to improve their electrochemical performance.
得益于新能源汽车的推广,锂离子电池行业迎来了蓬勃发展的时期。当前锂离子电池产业发展迅速,潜力巨大。因此,为了获得更好的锂离子电池,许多研究人员将研究重点转向了锂离子电池。本文将从锂离子电池的概述、锂离子电池的基本性能指标、正极材料的分类和制备方法等方面对锂离子电池正极材料进行文献综述。进一步分析锂离子电池正极材料的现状及改性策略,以提高其电化学性能。
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引用次数: 2
Simulation of deformation behaviour of Aluminium 7075 during Equal Channel Angular Pressing (ECAP) 7075铝合金等径角挤压变形行为模拟
Pub Date : 2023-01-01 DOI: 10.1051/matecconf/202337401002
H. Shagwira, J. Obiko, F. Mwema, T. Jen
This paper presents a finite element simulation of equal channel angular pressing (ECAP) since it is one of the most common and successful severe plastic deformation techniques. This study reports the influence of the most significant factors influencing the ECAP technique. Through finite element simulation, the effect of the die geometry, workpiece geometry, and the pressing speed on the effective strain distributions, damage, and pressing loads, were investigated. The influence of the ECAP method on different material models is also presented. Additionally, the prospective expansion and future applications of ECAP are herein highlighted. From the results, the die geometry of a 90° channel imparts the highest strains during ECAP. Additionally, specimens of rectangular geometry are susceptible to cracking and damage as compared to circular samples. It was found that very high processing speeds (>7mm/sec) are undesirable during ECAP since they cause very high internal stresses to the structure of the workpieces. Besides, processing at room temperature can achieve homogeneous strain distribution with minimum sample damage.
由于等通道角挤压是最常见和最成功的剧烈塑性变形技术之一,本文对其进行了有限元模拟。本研究报告了影响ECAP技术的最重要因素。通过有限元仿真,研究了模具几何形状、工件几何形状和冲压速度对有效应变分布、损伤和冲压载荷的影响。介绍了ECAP方法对不同材料模型的影响。此外,本文还强调了ECAP的扩展前景和未来的应用。从结果来看,90°通道的模具几何形状在ECAP期间具有最高的应变。此外,与圆形样品相比,矩形几何形状的样品容易开裂和损坏。研究发现,在ECAP过程中,非常高的加工速度(>7mm/秒)是不可取的,因为它们会对工件的结构造成非常高的内应力。此外,在室温下加工可以实现均匀的应变分布和最小的样品损伤。
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引用次数: 0
Emerging technologies for conversion of sustainable macroalgal carrageenan biomass into L-lactic acid: A state-of-the-art review 可持续大藻卡拉胶生物质转化为l -乳酸的新兴技术:最新进展综述
Pub Date : 2023-01-01 DOI: 10.1051/matecconf/202337701019
Kevin Tian Xiang Tong, I. Tan, H. Foo, Stephanie Yen San Chan, T. Hadibarata, M. Lam
The environmental awareness and concerns (plastic pollution) worldwide have driven the development of sustainable and environmentally friendly biopolymer derived from renewable materials. Biopolymers, especially L-lactic acid (L-LA) have played a crucial role in manufacturing polylactic acid, a biodegradable thermoplastic. Recently, L-LA production from non-edible macroalgal biomass has gained immense attraction due to it offers the simplest saccharification process for the biorefinery route. However, the commercialization of macroalgal-based L-LA is still limited due to high production costs. This paper has comprehensively reviewed the potential and development of third-generation feedstock for L-LA production, including significant technological barriers to be overcome for potential commercialization purposes. Then, an insight into the state-of-the-art hydrolysis and fermentation technologies using macroalgae as feedstock are also deliberated in detail. Furthermore, this review provides a conceivable picture of macroalgae-based L-LA biorefinery and future research directions that can be served as an important guideline for scientists, policymakers, and industrial players.
世界范围内的环保意识和对塑料污染的关注推动了可再生材料衍生的可持续环保生物聚合物的发展。生物聚合物,特别是l -乳酸(L-LA)在制造聚乳酸(一种可生物降解的热塑性塑料)中起着至关重要的作用。最近,从非食用大藻生物质中生产L-LA获得了巨大的吸引力,因为它为生物炼制路线提供了最简单的糖化过程。然而,由于生产成本高,基于大藻的L-LA的商业化仍然受到限制。本文全面回顾了用于L-LA生产的第三代原料的潜力和发展,包括潜在商业化目的需要克服的重大技术障碍。然后,深入了解最先进的水解和发酵技术,使用大型藻类作为原料也进行了详细的审议。此外,本文还展望了基于大藻类的L-LA生物炼制的前景和未来的研究方向,可为科学家、决策者和行业参与者提供重要的指导。
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引用次数: 0
Feasibility study on construction of RCC gravity dam under special climatic conditions in Tibet 西藏特殊气候条件下碾压混凝土重力坝建设可行性研究
Pub Date : 2023-01-01 DOI: 10.1051/matecconf/202338001029
Ni Pu, Jingyu Wang, Weibin Zhong, Nan Zheng, Jinming Ren
According to the experience in the construction of water conservancy and hydropower projects in the Mainland, RCC dam construction has two main advantages: the rapid construction speed of roller compacted concrete can realize early power generation, and the price of fly ash is much lower than that of cement, which can reduce the project cost. Tibet has special geographical environment and climatic conditions, and generally has the characteristics of “high altitude, low pressure, low temperature, large temperature difference between day and night, and dry climate”. Taking the dam-building environment in central Tibet as an example, through investigation and research and analogy of similar projects, this paper analyzes the adaptability of construction of RCC gravity dams in Tibet from the aspects of geographical environment, climatic conditions, material properties, construction progress, and project cost. Adaptability to high altitudes. It provides a reference for choosing a safe, reliable, economical and reasonable dam type in the construction of water conservancy and hydropower projects. It provides reference for selecting safe, reliable, economical and reasonable dam types in water conservancy and hydropower engineering construction.
根据内地水利水电工程的建设经验,碾压混凝土大坝建设主要有两个优势:碾压混凝土施工速度快,可实现早期发电,粉煤灰价格远低于水泥,可降低工程成本。西藏具有特殊的地理环境和气候条件,总体上具有“海拔高、气压低、气温低、昼夜温差大、气候干燥”的特点。以藏中地区筑坝环境为例,通过调查研究和类似工程的类比,从地理环境、气候条件、材料特性、施工进度、工程造价等方面分析了西藏地区碾压混凝土重力坝建设的适应性。对高海拔的适应性。为水利水电工程建设中选择安全、可靠、经济、合理的坝型提供参考。为水利水电工程建设中选择安全、可靠、经济、合理的坝型提供参考。
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引用次数: 0
Limits and possibilities of thermodynamic modelling of autogenous self-healing of concrete 混凝土自愈的热力学模型的限制和可能性
Pub Date : 2023-01-01 DOI: 10.1051/matecconf/202337809003
Daniel Lahmann, S. Kessler
Autogenous self-healing of water retaining concrete structures is included in Eurocode 1992-3 as a possibility to heal cracks up to a width of 200 μm without additional repair. In this self-healing scenario water flow through a crack should result in a progressive closure of the fracture, mainly due to CaCO3 precipitation, when certain hydraulic gradients are met, the pH of the water is > 5.5 and the concentration of CO2 in the water remains < 40 mg*L-1. The material composition is not further restricted by the regulation. However, despite standardization, the healing effect seems to be random in practice, which requires further research, while experiments aimed at quantifying autogenous self-healing are expensive and time-consuming. Thermodynamic models could support in estimating the effect of different environments such as groundwater or seawater exposure on autogenous self-healing. Moreover, adjusting the water chemistry according to the conditions of different construction sites and changing the material design could easily be considered. In this study thermodynamic models of a hydrated CEM I 52.5 R paste that is exposed to either simulated groundwater or seawater are discussed concerning the influence on autogenous self-healing and compared to experimental and literature data.
欧洲规范1992-3中包含了自愈水混凝土结构的可能性,即愈合宽度达200 μm的裂缝而无需额外修复。在这种自愈情景中,水流通过裂缝会导致裂缝逐渐闭合,这主要是由于CaCO3的沉淀,当满足一定的水力梯度时,水的pH值> 5.5,水中CO2浓度保持在< 40 mg*L-1。该法规没有进一步限制材料成分。然而,尽管标准化,但在实践中愈合效果似乎是随机的,这需要进一步研究,而旨在量化自愈的实验既昂贵又耗时。热力学模型可支持估算不同环境(如地下水或海水)对自愈的影响。此外,还可以考虑根据不同施工场地的条件调整水化学成分,改变材料设计。本研究讨论了水合CEM I 52.5 R膏体暴露于模拟地下水或海水中的热力学模型,并与实验和文献数据进行了比较。
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引用次数: 0
Feasibility of Visible Near-Infrared Hyperspectral Imaging in Detection of Calcium Hypochlorite in Sago Flour 可见近红外高光谱成像检测西米粉中次氯酸钙的可行性
Pub Date : 2023-01-01 DOI: 10.1051/matecconf/202337701005
Ming Hao Lee, A. Saptoro, K. Lim, H. Chua, T. Vu, Nurleyna Yunus, Hasnain Hussain
The general public perspective on sago flour quality is based on the perceived colour appearances. This contributed to the potential of food fraud by excessive usage of bleaching agents such as calcium hypochlorite (CHC) to alter the product’s colour. Conventional methods to detect and quantify CHC such as titration and chromatography are time-consuming, expensive and limited to laboratory setups only. In this research, visible near-infrared hyperspectral imaging (Vis-NIR HSI) was combined with partial least squares regression (PLSR) model to quantify CHC in pure sago flour accurately and rapidly. Hyperspectral images with the spectral region of 400 nm to 1000 nm were captured for CHC-pure sago mixture samples with CHC concentration ranging from 0.005 w/w% to 2 w/w%. Mean reflectance spectral data was extracted from the hyperspectral images, and was used as inputs to develop the PLSR model to predict the CHC concentration. The PLSR model achieved the commendable predictive results in this study, with Rp = 0.9509, RMSEP = 0.1655 and MAPEP of 3.801%, proving that Vis-NIR HSI can effectively predict the concentration of CHC in sago flour.
一般公众对西米面粉质量的看法是基于感知到的颜色外观。由于次氯酸钙(CHC)等漂白剂的过量使用改变了产品的颜色,这增加了食品欺诈的可能性。传统的检测和定量CHC的方法,如滴定法和色谱法,耗时、昂贵且仅限于实验室设置。本研究采用可见光近红外高光谱成像(Vis-NIR HSI)与偏最小二乘回归(PLSR)模型相结合的方法,对纯西米粉中的CHC进行了准确、快速的定量分析。CHC-纯西米混合物样品的CHC浓度为0.005 w/w% ~ 2 w/w%,可获得光谱区域为400 ~ 1000 nm的高光谱图像。从高光谱图像中提取平均反射率光谱数据,并将其作为PLSR模型的输入,用于预测CHC浓度。PLSR模型在本研究中取得了令人满意的预测结果,Rp = 0.9509, RMSEP = 0.1655, MAPEP为3.801%,证明Vis-NIR HSI可以有效预测西米粉中CHC的浓度。
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引用次数: 0
Evaluation of the self-healing effect in cement-based materials with embedded cementitious capsules by means of Acoustic Emission techniques 用声发射技术评价嵌入胶凝胶囊的水泥基材料的自愈效果
Pub Date : 2023-01-01 DOI: 10.1051/matecconf/202337804004
G. Anglani, P. M. Montanari, Jean Marc Tulliani, G. Lacidogna, P. Antonaci
Due to its low tensile strength and the presence of defects brought on by improper construction methods or other factors, cracks in concrete are practically inevitable. For reinforced-concrete structures, even if cracks do not necessarily increase the risk of collapse, they unquestionably hinder aspects such as service life. Self-healing cementitious materials have been developed because of growing concern for the security and sustainability of structures. For these new materials to be used in actual structures, it is essential to conduct research into the self-repair effect that they may offer, and possibly quantify it directly on-site, by means of non-destructive methods. In this sense, the objective of this work is to use Acoustic Emission (AE) analyses to non-destructively characterise the response of an autonomic capsule-based system, as a function of the specific polymeric healing agents contained in the capsules. Comparisons will be made between the reference and selfhealing specimens, and between the different self-healing specimens themselves, through the analysis of such parameters as the ultimate load, absorbed fracture energy, and emitted Acoustic Emission (AE) energy. Such type of analysis can give valuable insights not only on quantitative but also on qualitative aspects (such as the level of brittleness or ductility introduced by the specific self-healing system adopted) in view of possible applications in real structures.
由于混凝土本身抗拉强度低,加上施工方法不当或其他因素造成的缺陷,混凝土裂缝几乎是不可避免的。对于钢筋混凝土结构,即使裂缝不一定会增加倒塌的风险,但它们无疑会影响使用寿命等方面。自愈胶结材料的发展是由于人们对结构的安全性和可持续性的日益关注。为了将这些新材料应用于实际结构中,有必要对它们可能提供的自我修复效果进行研究,并可能通过非破坏性方法直接在现场进行量化。从这个意义上说,这项工作的目的是使用声发射(AE)分析来非破坏性地表征基于自主胶囊的系统的响应,作为胶囊中包含的特定聚合物愈合剂的功能。通过对极限载荷、吸收断裂能、发射声发射能等参数的分析,对参考试件与自愈试件、不同自愈试件本身进行比较。这种类型的分析不仅可以在定量方面,而且可以在定性方面(例如所采用的特定自愈系统引入的脆性或延性水平)提供有价值的见解,考虑到实际结构的可能应用。
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引用次数: 0
Self-sensing Sustainable Cementitious Mixtures Incorporating Carbon Fibres 含有碳纤维的自感知可持续胶凝混合物
Pub Date : 2023-01-01 DOI: 10.1051/matecconf/202337805007
Thamer Almotlaq, M. Saafi
This paper focuses on sustainable cementitious composites in terms of their conductivity, hydration and self-sensing properties, which are key features for smart city infrastructures. Smart cities have massive infrastructures that are interconnected, transmitting data and information for health-monitoring and performance optimization. In this regard, having them made of sustainable building materials (concrete) that are also sufficiently conductive, will be a suitable solution for structures’ performance. The studied sustainable cementitious mixtures are made by sea components (sea water and sea sand), which are abundant resources. The primary goal of this study is to improve the mixes’ electrical conductivity and sensitivity. To achieve this goal, milled carbon fibres (MCFs) and chopped carbon fibres (CCFs) in 6 different proportions were added to the cementitious mixes. The experimental study is divided into impedance spectroscopy to study the conductivity and hydration development, and self-sensing properties, conducted on various mix designs. The results show that incorporating sea components improve the electrical conductivity of the mixes by 40-50%. Further improvements were achieved by adding MCF as it shows a remarkable reduction by 60% compared to the plain ss-sw (sea sand and sea water) samples. Adding CCF improved the conductivity even further and resulted in sample’s resistivity as low as 53 Ωcm after 1 year of curing time.
本文重点研究了可持续胶凝复合材料的导电性、水化性能和自传感性能,这些都是智慧城市基础设施的关键特征。智慧城市拥有庞大的基础设施,这些基础设施相互连接,传输数据和信息,用于健康监测和性能优化。在这方面,让它们由可持续建筑材料(混凝土)制成,并且具有足够的导电性,将是结构性能的合适解决方案。所研究的可持续胶凝混合物是由海洋成分(海水和海砂)制成的,这是一种丰富的资源。本研究的主要目的是提高混合物的导电性和灵敏度。为了实现这一目标,将6种不同比例的研磨碳纤维(mcf)和切碎碳纤维(ccf)添加到胶凝混合物中。实验研究分为阻抗谱研究电导率和水化发展,以及自传感性能,在各种混合设计中进行。结果表明,加入海洋组分可使混合料的导电性提高40-50%。添加MCF后,性能得到了进一步改善,因为与普通的ss-sw(海砂和海水)样品相比,MCF显著降低了60%。添加CCF进一步提高了电导率,在固化1年后,样品的电阻率低至53 Ωcm。
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引用次数: 0
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