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Simultaneous attenuation of gamma ray and neutrons in single layer concrete shield 单层混凝土屏蔽层中伽马射线和中子的同时衰减
IF 0.7 4区 工程技术 Q3 Engineering Pub Date : 2021-01-01 DOI: 10.32047/cwb.2021.26.6.5
Majid Safamehr, M. Izadinia, Seyed Hamid Hashemi, Seyed Jalil Hoseini
The ability to create various compounds has made concrete one of the most suitable materials for constructing radiation shields. In this investigation, hematite and magnetite aggregates were used to replace ordinary aggregate, separately and completely in two stages. Boron carbide was also substituting cement at percentages of 2.5, 5, and 10 by mass. The density test, gamma irradiation with Co 60 and neutron irradiation with Am-Be 241 were performed. According to the results, the replacement of ordinary aggregates with hematite aggregates in concrete, improved the linear attenuation coefficient and macroscopic cross section by 17% and 73%, respectively. These parameters increased by 37% and 105%, respectively, by the use of magnetite aggregates. Moreover, with the addition of a maximum of 10% boron carbide to the concrete, the macroscopic cross-section increased by 120%, however, the linear attenuation coefficient decreased by between 5% and 8%. This means that it is possible to have a suitable attenuation of gamma ray and neutron beams in a single layer of concrete shield simultaneously. In addition, the results of the tests and Monte Carlo simulation were found to have good consistency.
混凝土具有制造各种化合物的能力,这使得它成为建造辐射屏蔽层最合适的材料之一。本试验分两个阶段分别用赤铁矿和磁铁矿骨料代替普通骨料。碳化硼也以2.5、5和10的质量百分比取代水泥。进行了密度试验、Co - 60 γ辐照和Am-Be - 241中子辐照。结果表明,用赤铁矿骨料代替普通骨料,混凝土的线性衰减系数和宏观截面分别提高了17%和73%。使用磁铁矿集料后,这些参数分别提高了37%和105%。碳化硼掺量最高为10%时,混凝土宏观截面增大120%,但线性衰减系数减小5% ~ 8%。这意味着在一层混凝土屏蔽层中同时对伽马射线和中子束进行适当的衰减是可能的。实验结果与蒙特卡罗模拟结果具有较好的一致性。
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引用次数: 0
Material properties of the light mass bricks from an 800 year old Heritage site in India 来自印度800年历史遗址的轻质砖的材料特性
IF 0.7 4区 工程技术 Q3 Engineering Pub Date : 2021-01-01 DOI: 10.32047/cwb.2021.26.2.4
N. K. Degloorkar, Ratish K. Pancharathi
Restoration and preservation of Heritage Structures in any countryis a challenging task and sometimes requires urgent attention. Moreover, it is important for sustenance of culture and heritage of the society. But many times, it is very diffi cult to find matching materials used in the past and hence due to use of available cementitious materials there can be degeneration of existing material. In view of this, there is a need to characterize these ancient materials and develop alternate materials with almost similar characteristics. With this knowledge, an alternate material similar in mineral composition and physical properties need to be developed, which will not have compatibility issues during and after repair. In the present study, the material characterization of an ancient floating brick at an Indian Heritage site was examined using modern analytical techniques like SEM-EDS, XRD and FTIR. In addition, the physical properties like specific gravity, bulk density, voids ratio and porosity were also determined. From the analysis, it could be confirmed that the bricks were light in weight due to the pores content and could float in water due to the non-interconnected porosity. Also, the presence of quartz, alumina and hematite from SEM-EDS analysis confirmed that these bricks were made of firing the clay, at lower temperatures, to induce pores. This low temperature firing of clay was supported by FTIR analysis indicating the presence of Si-O bond that would have disappeared at higher temperature.
文物建筑的修复和保护在任何国家都是一项具有挑战性的任务,有时需要迫切关注。此外,它对社会文化和遗产的维持也很重要。但很多时候,很难找到与过去使用的材料相匹配的材料,因此由于使用现有的胶凝材料,可能会导致现有材料的退化。鉴于此,有必要对这些古代材料进行表征,并开发具有几乎相似特征的替代材料。有了这些知识,需要开发一种在矿物成分和物理性质上相似的替代材料,这种材料在修复期间和修复后都不会有兼容性问题。在本研究中,使用SEM-EDS、XRD和FTIR等现代分析技术,对印度遗产地的古代浮砖的材料特征进行了研究。此外,还测定了材料的比重、容重、空隙率、孔隙率等物理性质。通过分析可以确定,由于孔隙含量的原因,砖的重量较轻,并且由于孔隙不相互连接,砖可以漂浮在水中。此外,通过SEM-EDS分析,石英、氧化铝和赤铁矿的存在证实,这些砖是由粘土在较低温度下烧制而成,以诱导气孔。FTIR分析支持这种低温烧制粘土,表明存在Si-O键,该键在高温下会消失。
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引用次数: 0
Effect of ASR expansion on mechanical properties of concrete ASR膨胀对混凝土力学性能的影响
IF 0.7 4区 工程技术 Q3 Engineering Pub Date : 2021-01-01 DOI: 10.32047/cwb.2021.26.1.2
Alkan Hafçi, L. Turanli, F. Bektaş
In this experimental study the effect of alkali silica reaction [ASR] on the mechanical properties of concrete namely compressive strength, fl exural strength, splitting tensile strength, modulus of elasticity and pull-out strength is presented. The effect of the specimens’ geometry on ASR expansion has also been studied. The results confirm that ASR expansion of over 0.04% causes significant losses in the mechanical properties of concrete, albeit at differing rates. Moreover, this study proves that the specimen geometry has an important role on ASR expansion rate.
试验研究了碱硅反应对混凝土抗压强度、抗折强度、劈裂抗拉强度、弹性模量和抗拔强度等力学性能的影响。研究了试样几何形状对ASR膨胀的影响。结果证实,ASR膨胀超过0.04%会导致混凝土力学性能的显著损失,尽管损失幅度不同。此外,本研究还证明了试样几何形状对ASR膨胀率有重要影响。
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引用次数: 1
Kinds of concrete shrinkages, their importance and prevention methods 混凝土收缩的种类、重要性及预防方法
IF 0.7 4区 工程技术 Q3 Engineering Pub Date : 2021-01-01 DOI: 10.32047/cwb.2021.26.2.5
W. Kurdowski
The basis for the geopolymers production was drawn up by prof. Kühl, well known to present day from the introduction of the modulus of clinker lime saturation: This Kühl’s formula was lined on the assumption that the best clinker should be composed of C3S, C3A and C2F and the mass ratio of CaO in respect to other components is equal adequately: 2.8, 1.65 and 0.70. The analyses of the equilibrium condition in the four components system led Kühl to the so-called lime criterion, equal to the permissible maximal lime content in clinker, in the conditions far from the equilibrium: One of the unfavourable properties of concrete is shrinkage which is linked with the volume changes of cement paste. We distinguish the following kinds of shrinkage: – “chemical” shrinkage called also the contraction or Le Chatelier shrinkage, – plastic shrinkage, – autogenic shrinkage or spontaneous, sometimes called auto drying, – drying shrinkage. There are several methods to eliminate concrete shrinkage. The ettringite crystallization is one of the inorganic compounds methods and is based on Klein’s complex addition to cement. This complex is causing the rapid ettringite formation and the shrinkage is diminished. There are also organic admixtures which action is the reduction of the water surface tension. There are surface-active additions that are reducing this tension, in capillaries. The organic admixtures which are diminishing the shrinkage are based on neopentyl glycol or similar chemical compounds. In the study, the shrinkage-reducing admixture BASF Master Life SRA 815 alone and with CaO addition were examined. It was shown that CaO addition is giving very low diminishing of cement shrinkage, contrary to the fluid admixture Master Life SRA 815 which has a high diminishing influence on cement shrinkage. However, the simultaneous addition of CaO is increasing the diminishing influence of this fluid admixture. The addition of Klein’s complex does not influence of shrinkage but its simultaneous addition with Master Life SRA 815 gives higher shrinkage diminishing.
地聚合物生产的基础是由k hl教授提出的,他从熟料石灰饱和模量的引入到今天都很出名:k hl的公式是基于最好的熟料应该由C3S、C3A和C2F组成,CaO相对于其他组分的质量比是充分相等的:2.8、1.65和0.70。通过对四组分体系平衡条件的分析,k hl得出了所谓的石灰准则,即熟料中允许的最大石灰含量,在远离平衡的条件下:混凝土的不利性能之一是收缩,这与水泥浆体的体积变化有关。我们区分以下几种收缩:-“化学”收缩也称为收缩或勒夏特列收缩,-塑性收缩,-自生收缩或自发,有时称为自动干燥,-干燥收缩。消除混凝土收缩的方法有几种。钙矾石结晶法是一种无机化合物方法,其基础是水泥中克莱因络合物的加入。这种复合体导致钙矾石快速形成,收缩减少。也有有机外加剂,其作用是降低水的表面张力。在毛细血管中,有表面活性添加剂可以降低这种张力。减少收缩的有机外加剂是基于新戊二醇或类似的化合物。研究了巴斯夫主寿命减水剂SRA 815单独和添加CaO的减水剂。结果表明,CaO的加入对水泥收缩的抑制作用很小,而Master Life SRA 815对水泥收缩的抑制作用很大。然而,同时加入CaO会增加这种流体混合物的影响。克莱因配合物的加入对收缩率没有影响,但与主寿命SRA 815同时加入后,收缩率减小较大。
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引用次数: 2
Mechanical properties of magnesium phosphate cement incorporating basalt fibers 含玄武岩纤维的磷酸镁水泥的力学性能
IF 0.7 4区 工程技术 Q3 Engineering Pub Date : 2021-01-01 DOI: 10.32047/cwb.2021.26.3.5
A. Pehlivan
In this experimental study, the effect of basalt fibers on the mechanical properties of magnesium phosphate cement [MPC] was investigated. Compressive strength, splitting tensile strength, flexural strength and modulus of elasticity, were introduced. It was observed that mechanical properties were significantly enhanced with the addition of silica fume, especially splitting tensile and flexural strength were enhanced with the increase of basalt fibers. However, for mixtures without silica fume addition, high content of fibers adversely affected the mechanical properties. Silica fume addition was found to be significant in increasing the bonding mechanism between basalt fibers and the MPC matrix. Thus, combined usage of silica fume and basalt fibers was found to be effective. A molar ratio of magnesia to ammonium dihydrogen phosphate of 8 was observed to have better results with respect to a molar ratio of 6, however, this distinction was not very apparent, when silica fume was added to both mixtures.
本试验研究了玄武岩纤维对磷酸镁水泥力学性能的影响。介绍了抗压强度、劈裂抗拉强度、抗弯强度和弹性模量。结果表明,硅灰的加入显著提高了材料的力学性能,特别是随着玄武岩纤维含量的增加,材料的劈裂抗拉强度和抗弯强度均有所提高。然而,对于不添加硅粉的混合物,高纤维含量对机械性能有不利影响。发现硅灰的加入对增强玄武岩纤维与MPC基体之间的结合机制有显著作用。因此,硅灰与玄武岩纤维的复合使用是有效的。氧化镁与磷酸二氢铵的摩尔比为8时,与摩尔比为6时相比,观察到的结果更好,然而,当硅灰加入到这两种混合物中时,这种区别不是很明显。
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引用次数: 1
Ferrophosphorus aggregates shielding properties on heavy concrete exposed to gamma-rays, cesium-137 source 磷铁聚集在暴露于伽马射线、铯-137源的重混凝土上的屏蔽特性
IF 0.7 4区 工程技术 Q3 Engineering Pub Date : 2021-01-01 DOI: 10.32047/cwb.2021.26.4.4
Reza Farokhzad, A. Dadashi, A. Sohrabi
This study aims to investigate the linear attenuation coefficient and density of samples made of ferrophosphorus and typical aggregates, steel powder, and nanosilica powder in different ratios. Therefore, 60 concrete samples with dimensions of 15×15×15 cm and different contents of the mentioned materials were prepared. After the density was measured, the linear attenuation coefficients of the samples were measured by gamma radiation emitted from the cesium-137 source. The results showed that ferrophosphorus was the most effective factor in increasing the linear attenuation coefficient and the density of the concrete. After ferrophosphorus, steel and nanosilica powder – although much less than ferrophosphorus – increased the density and linear attenuation coefficient. The sample made of 100% ferrophosphorus aggregate and 20% steel powder without nanosilica powder had the highest density of 4395 kg/m3, and the sample made of 100% typical aggregate and 10% steel powder, without nanosilica powder, had the lowest density equal to 2269 kg/m3. The highest linear attenuation coefficient – 0.295 was related to the sample made of 100% ferrophosphorus, 30% steel powder, and 5% nanosilica powder. The lowest linear attenuation coefficient – 0.151 was related to the sample made of 8% nanosilica, without the ferrophosphorus and steel powder. The results indicated that the concrete density was directly correlated with the linear attenuation coefficient.
本研究旨在研究磷铁与典型骨料、钢粉和纳米二氧化硅粉按不同比例制成的样品的线性衰减系数和密度。因此,制备了60个尺寸为15×15×15 cm的混凝土样品,样品中上述材料的含量不同。密度测量完成后,用铯-137源发射的伽马射线测量了样品的线性衰减系数。结果表明,磷铁是提高混凝土线性衰减系数和密度的最有效因素。在磷铁之后,钢和纳米二氧化硅粉-尽管比磷铁少得多-增加了密度和线性衰减系数。100%磷铁骨料和20%钢粉混合而不含纳米二氧化硅粉的样品密度最高,为4395 kg/m3; 100%典型骨料和10%钢粉混合而不含纳米二氧化硅粉的样品密度最低,为2269 kg/m3。100%磷铁、30%钢粉、5%纳米二氧化硅粉的线性衰减系数最高,为0.295。当纳米二氧化硅含量为8%,不含磷铁和钢粉时,线性衰减系数最低,为0.151。结果表明,混凝土密度与线性衰减系数直接相关。
{"title":"Ferrophosphorus aggregates shielding properties on heavy concrete exposed to gamma-rays, cesium-137 source","authors":"Reza Farokhzad, A. Dadashi, A. Sohrabi","doi":"10.32047/cwb.2021.26.4.4","DOIUrl":"https://doi.org/10.32047/cwb.2021.26.4.4","url":null,"abstract":"This study aims to investigate the linear attenuation coefficient and density of samples made of ferrophosphorus and typical aggregates, steel powder, and nanosilica powder in different ratios. Therefore, 60 concrete samples with dimensions of 15×15×15 cm and different contents of the mentioned materials were prepared. After the density was measured, the linear attenuation coefficients of the samples were measured by gamma radiation emitted from the cesium-137 source. The results showed that ferrophosphorus was the most effective factor in increasing the linear attenuation coefficient and the density of the concrete. After ferrophosphorus, steel and nanosilica powder – although much less than ferrophosphorus – increased the density and linear attenuation coefficient. The sample made of 100% ferrophosphorus aggregate and 20% steel powder without nanosilica powder had the highest density of 4395 kg/m3, and the sample made of 100% typical aggregate and 10% steel powder, without nanosilica powder, had the lowest density equal to 2269 kg/m3. The highest linear attenuation coefficient – 0.295 was related to the sample made of 100% ferrophosphorus, 30% steel powder, and 5% nanosilica powder. The lowest linear attenuation coefficient – 0.151 was related to the sample made of 8% nanosilica, without the ferrophosphorus and steel powder. The results indicated that the concrete density was directly correlated with the linear attenuation coefficient.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75767764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Unground granulated slag as a substitute for natural aggregate during concrete production 在混凝土生产中,未磨碎的矿渣作为天然骨料的替代品
IF 0.7 4区 工程技术 Q3 Engineering Pub Date : 2021-01-01 DOI: 10.32047/cwb.2021.26.3.3
Ru Wang, Ziyan Xi, Gaoyong Wang
Styrene-butadiene copolymer [SB] modified cement-based materials are widely used, but the addition of SB can delay the setting and hardening of cement, which limits its application in some projects. In this paper, nanosilica was selected as the modifying component to study its influence on the early hydration, setting and hardening of SB/cement composite material. By measuring the setting time and early strength of nanosilica modified SB/cement composite material, the influence of nanosilica on the setting and hardening process of composite cementitious material was analyzed. The hydration heat of nanosilica modified SB/cement composite material was determined by isothermal calorimetry, and its hydration products were examined by X-ray diffraction, so as to analyze the influence of nanosilica on the early hydration process of composite cementitious material. The results show that the addition of nanosilica can effectively promote the setting and hardening process of composite cementitious material, and the higher the dosage is, the more significant the effect is. It also indicates that addition of nanosilica accelerates the formation of ettringite and calcium hydroxide, by promoting the hydration of tricalcium aluminate and tricalcium silicate. Shortens the hydration induction period and acceleration period of the composite cementitious material and accelerates the hydration process, thereby shortening the setting time and increasing the early strength.
丁苯共聚物(SB)改性水泥基材料应用广泛,但SB的加入会延缓水泥的凝结和硬化,限制了其在某些工程中的应用。本文选择纳米二氧化硅作为改性组分,研究其对SB/水泥复合材料早期水化、凝结和硬化的影响。通过测定纳米二氧化硅改性SB/水泥复合材料的凝固时间和早期强度,分析纳米二氧化硅对复合胶凝材料凝固硬化过程的影响。采用等温量热法测定纳米二氧化硅改性SB/水泥复合材料的水化热,通过x射线衍射检测其水化产物,分析纳米二氧化硅对复合胶凝材料早期水化过程的影响。结果表明:纳米二氧化硅的加入能有效促进复合胶凝材料的凝固和硬化过程,且添加量越高,效果越显著。纳米二氧化硅的加入促进了铝酸三钙和硅酸三钙的水化作用,从而加速了钙矾石和氢氧化钙的形成。缩短了复合胶凝材料的水化诱导期和加速期,加速了水化过程,从而缩短了凝结时间,提高了早期强度。
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引用次数: 0
Contemporary challenges of science and technology – selected reflections 当代科学技术的挑战——精选思考
IF 0.7 4区 工程技术 Q3 Engineering Pub Date : 2021-01-01 DOI: 10.32047/cwb.2021.26.5.5
K. Furtak
Modern challenges of science and technology should not be considered in isolation from the past and changes that have taken place over the centuries. They have occurred in different ways in various periods of human history and in various spheres of human activity, including technology. The changes also concern construction and construction materials. All changes have been stimulated by, inter alia, science and they, in turn, have determined and stimulated the development of science. The soaring growth in science and technological development result in a rising social awareness of increasing and new issues both technological and social that must be addressed. At the present stage of civilisation evelopment, they cannot be solved separately. The environmental and energy impacts must also be included. Special attention was focused on construction materials and products, as well as technological aspects including the application of 3D printing technology in construction. They all belong to the development of civilisation in a broad sense. In construction, there is room for traditional materials and technologies and their new versions with the primacy, however, of new generation materials. The need to apply the achievements in disciplines other than construction has been emphasised.
科学和技术的现代挑战不应脱离过去和几个世纪以来发生的变化来考虑。它们以不同的方式出现在人类历史的不同时期和人类活动的不同领域,包括技术领域。这些变化还涉及建筑和建筑材料。所有的变化都是由科学引起的,而这些变化又决定和促进了科学的发展。科学技术的飞速发展导致社会对必须解决的日益增多的新技术和社会问题的认识不断提高。在文明发展的现阶段,这两个问题不可能单独解决。环境和能源影响也必须包括在内。特别关注的是建筑材料和产品,以及技术方面,包括3D打印技术在建筑中的应用。它们都属于广义的文明发展。在建筑领域,以新一代材料为主导的传统材料和技术及其新版本有发展空间。强调将成果应用于建筑以外的学科。
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引用次数: 0
Experimental investigation on strength properties of concrete incorporating ground pond ash 掺地塘灰混凝土强度特性试验研究
IF 0.7 4区 工程技术 Q3 Engineering Pub Date : 2021-01-01 DOI: 10.32047/cwb.2021.26.3.7
K. Yuvaraj, S. Ramesh
In the present era, the consumption of electricity has increased rapidly with each passing year, due to the industrialization. Coal is a raw material for the production of electricity in the thermal power stations. Particularly, a large amount of unused ash is dumped in ponds, which are major problem concerning many developing countries. Further, dumping of ash in ponds causes environmental hazards effects such as soil, land and water pollution. Identifying a viable alternative to utilize pond ash becomes a necessity, to avoid these environmental hazards. In this research work, an attempt has been made to partially replace cement by the pond ash as a supplementary cementitious material [SCM] in concrete, which will considerably reduce the hazardous effects of pond ash, to the environment. The pond ash was ground to 45 μm and it was used to replace the cement in concrete by proportions of 5, 10, 15, 20 and 25% by mass. Test on compressive strength, split tensile strength and modulus of rupture were conducted on concrete mixes. The result indicate that the addition of 10% pond ash to concrete significantly increased the strength properties of the concrete at the age of 7, 28, 56 and 90 days.
在当今时代,由于工业化,用电量每年都在快速增长。煤是火力发电站发电的原料。特别是,大量未使用的灰被倾倒在池塘中,这是许多发展中国家面临的主要问题。此外,向池塘倾倒灰渣会造成土壤、土地和水污染等环境危害效应。为了避免这些环境危害,确定一种可行的替代方法来利用池灰是必要的。本研究尝试用池灰替代部分水泥作为混凝土中的补充胶凝材料,从而大大降低池灰对环境的危害。将池灰磨成45 μm,按质量比为5%、10%、15%、20%和25%的比例替代混凝土中的水泥。对混凝土配合比进行了抗压强度、劈裂抗拉强度和断裂模量试验。结果表明:掺量为10%的塘灰显著提高了混凝土在龄期7、28、56和90 d时的强度性能;
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引用次数: 7
Mechanical and durability properties of sintered fly ash aggregate concrete 粉煤灰烧结骨料混凝土的力学性能和耐久性
IF 0.7 4区 工程技术 Q3 Engineering Pub Date : 2021-01-01 DOI: 10.32047/cwb.2021.26.5.3
S. Siva Chandran, K. Chinnaraju
Conservation of natural resources and effective management of waste materials that can harm our environment is a challenging phenomenon. This paper is focused to study the different properties of M30 grade concrete where the coarse aggregate has been completely replaced by commercially available sintered fly ash aggregate and it has proved to meet the target strength. To further improve the crack resisting behavior and tensile strength,basalt fibers was incorporated. The incorporation of fibers has improved the mechanical properties to around 3-4%. The RCPT and water absorption test has proved that the durability properties of sintered fly ash aggregate are within the standard specified.
保护自然资源和有效管理可能危害我们环境的废物是一项具有挑战性的现象。本文重点研究了M30级混凝土的不同性能,用市售的烧结粉煤灰骨料完全取代粗骨料,并证明其达到了目标强度。为了进一步提高材料的抗裂性能和抗拉强度,掺入了玄武岩纤维。纤维的掺入使机械性能提高了3-4%左右。经RCPT和吸水试验证明,烧结粉煤灰骨料的耐久性能在标准规定范围内。
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引用次数: 0
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Cement Wapno Beton
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