| 1. |
- Fan, Xu, et al.
(författare)
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Effects of different supplementary cementitious materials on the performance and environment of eco-friendly mortar prepared from waste incineration bottom ash
- 2022
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Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618. ; 356
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Tidskriftsartikel (refereegranskat)abstract
- Municipal solid waste incineration bottom ash (MSWIBA) is a by-product produced by municipal waste incineration treatment. In this study, MSWIBA particle size distribution, chemical composition and particle shape were investigated and confirmed its value for reuse in the construction field and its good research potential. MSWIBA was used as fine aggregates, while coal fly ash (FA) and ground granulated blast furnace slag (GGBFS) were used as auxiliary cementitious materials to replace part of cement to manufacture the eco-friendly mortar (EFM). The effect of FA/GGBFS on the mechanical and microscopic properties of EFM with different material ratios was mainly investigated. And the analysis of the environmental friendliness and economy of this EFM was made. The results show that the combination of FA and GGBFS at the same time reduces the early mechanical properties of the mortar. However, the strength developed rapidly after 7 days, with an increase of more than 6 times the rate before 7 days. Compared with GGBFS, FA is more helpful in improving the mechanical properties of the EFM. After 28 days of full hydration, the hydration products within the EFM are numerous and well bonded to each other. Not only do these hydration products increase the mechanical strength of EFM, but they also successfully solidify the hazardous components in MSWIBA and reduce their negative environmental effects. In addition, the use of MSWIBA instead of sand for mortar preparation reduces energy consumption and CO2 emissions, and it reduces the cost by more than 50 %. This indicates that MSWIBA may perform well in the future development of the civil infrastructures. As well as recycling waste resources, it makes a valuable contribution to the development of green and sustainable building materials.
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| 2. |
- Fan, Xu, et al.
(författare)
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New applications of municipal solid waste incineration bottom ash (MSWIBA) and calcined clay in construction: Preparation and use of an eco-friendly artificial aggregate
- 2023
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Ingår i: Construction and Building Materials. - 0950-0618. ; 387
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to prepare MSWIBA as eco-friendly artificial aggregates (EFAAs) by cold bond granulation technique using a low carbon limestone calcined clay cement (LC3). The water absorption rate of EFAAs is between 14.42 and 21.82%, and the maximum compressive strength can reach 2.5 MPa. Calcined clay particles can effectively adsorb heavy metal ions after absorbing water, and EFAAs can reduce the leaching value of toxic elements in MSWIBA by more than half on average. Compared to standard OPC cementitious materials, LC3 composites only need 50% of the energy and discharge 43% of the CO2, producing a more environmentally friendly artificial aggregate. In addition, the 28-day compressive strength of concrete was higher than 30 MPa on average after applying EFAAs to concrete. The good application capability shown by EFAAs, as well as their low energy consumption and low carbon environmental characteristics, promote the better application of MSWIBA in buildings.
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| 3. |
- Hong, Shuxian, et al.
(författare)
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Determination of impressed current efficiency during accelerated corrosion of reinforcement
- 2020
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Ingår i: Cement and Concrete Composites. - : Elsevier BV. - 0958-9465. ; 108
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Tidskriftsartikel (refereegranskat)abstract
- Impressed current technique is a widely adopted method for accelerating corrosion of steel reinforcement. The mass loss of steel can be theoretically estimated by Faraday's law with the assumption that all of the impressed current participated in the corrosion reaction. In the present study, accelerated corrosion process of reinforcing steel with impressed current was non-destructively traced by X-ray micro-computed tomography (μCT) with high accuracy. The mass loss of steel at different accelerated corrosion periods was analyzed and the efficiency of impressed current was calculated. It was found that the mass loss of steel did not always follow Faraday's law, and impressed current efficiencies varied with different corrosion periods. In the early corrosion periods, the water electrolysis occurred and lowered the current efficiency due to the high anode potential. While in the late corrosion periods, the natural corrosion caused the current efficiency to exceed 100%.
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| 4. |
- Liu, Jun, et al.
(författare)
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Resource utilization of municipal solid waste incineration fly ash - cement and alkali-activated cementitious materials: A review
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 852
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Forskningsöversikt (refereegranskat)abstract
- The increase in municipal solid waste (MSW) production has led to an increase in MSW incineration fly ash (MSWIFA) production. MSWIFA contains toxic and harmful substances such as heavy metals and dioxins, which can cause harm to the environment if not treated properly. Only a few MSWIFAs will be landfilled directly, and the rest will need to be treated by other methods. The treatment of MSWIFA can be divided into three types: separation, stabilization/solidification (S/S), and thermal treatment, which are either not fully developed or too costly. Resource utilization is a sustainable means of treating MSWIFA. MSWIFA is used in the production of cement and alkali-activated cementitious materials as a means of resource utilization with significant advantages. This can alleviate the consumption of nature and reduce greenhouse gas emissions in conventional cement production. Compared with MSWIFA cement, MSWIFA alkali-activated cementitious material can be achieved with almost no consumption of natural resources, which is worthy of further research to realize the large-scale application of MSWIFA. At the end of the paper, the perspective of separation of dioxins from MSWIFA, co-processing of MSWI ash, and production of “MSWIFA green materials” is presented.
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| 5. |
- Andersson, Jennie, 1986, et al.
(författare)
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Ship-scale CFD benchmark study of a pre-swirl duct on KVLCC2
- 2022
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Ingår i: Applied Ocean Research. - : Elsevier Ltd. - 0141-1187 .- 1879-1549. ; 123
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Tidskriftsartikel (refereegranskat)abstract
- Installing an energy saving device such as a pre-swirl duct (PSD) is a major investment for a ship owner and prior to an order a reliable prediction of the energy savings is required. Currently there is no standard for how such a prediction is to be carried out, possible alternatives are both model-scale tests in towing tanks with associated scaling procedures, as well as methods based on computational fluid dynamics (CFD). This paper summarizes a CFD benchmark study comparing industrial state-of-the-art ship-scale CFD predictions of the power reduction through installation of a PSD, where the objective was to both obtain an indication on the reliability in this kind of prediction and to gain insight into how the computational procedure affects the results. It is a blind study, the KVLCC2, which the PSD is mounted on, has never been built and hence there is no ship-scale data available. The 10 participants conducted in total 22 different predictions of the power reduction with respect to a baseline case without PSD. The predicted power reductions are both positive and negative, on average 0.4%, with a standard deviation of 1.6%-units, when not considering two predictions based on model-scale CFD and two outliers associated with large uncertainties in the results. Among the variations present in computational procedure, two were found to significantly influence the predictions. First, a geometrically resolved propeller model applying sliding mesh interfaces is in average predicting a higher power reduction with the PSD compared to simplified propeller models. The second factor with notable influence on the power reduction prediction is the wake field prediction, which, besides numerical configuration, is affected by how hull roughness is considered. © 2022 The Authors
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| 6. |
- Li, Zhenlin, et al.
(författare)
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Research on the durability and Sustainability of an artificial lightweight aggregate concrete made from municipal solid waste incinerator bottom ash (MSWIBA)
- 2023
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Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618. ; 365
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Tidskriftsartikel (refereegranskat)abstract
- This study chooses to use three common cementing materials, Portland cement (OPC), ground granulated blast furnace slag (GGBFS) and fly ash (FA), as the binder for the production of three artificial lightweight coarse aggregates (ALCAs) through cold bonding with municipal solid waste incineration bottom ash (MSWIBA) in which MSWIBA accounts for 70% of the total content by volume. In this study, three ALCAs were used to replace 0%, 30%, 60%, and 100% of natural aggregates used in the production of concrete. Through capillary water absorption and rapid migration of chloride ions, the effect of the replacement amount of ALCAs on the durability of concrete was explored. Additionally, in accordance with the Material Sustainability Index (MSI), a statistical analysis of the CO2 emissions, energy consumption and cost of the concrete made of the three ALCAs was carried out. Studies have shown that ALCAs can improve the Interfacial Transition Zone (ITZ) and pore structure of concrete, thereby improving the ability of concrete to resist chloride ion penetration. In addition, the use of ALCAs can reduce the cost of concrete. Among the ALCAs used in this study, those which use GGBFS and FA as adhesives (without OPC) can improve the durability of concrete the most and reduce CO2 emissions.
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| 7. |
- Liu, Jun, et al.
(författare)
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Novel recycling application of high volume municipal solid waste incineration bottom ash (MSWIBA) into sustainable concrete
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 838
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Tidskriftsartikel (refereegranskat)abstract
- Since municipal solid waste incineration bottom ash (MSWIBA) contains some heavy metals that are harmful to the groundwater and soil, this study proposes an effective and new approach to deal with high-volume MSWIBA. Selecting 70% MSWIBA, 10% ordinary Portland cement (OPC), 10% fly ash/ground granulated blast furnace slag (FA/GGBFS), and 1% volume of polypropylene (PP) fiber as the raw materials, this project designed and manufactured cold-bonded fiber aggregates (CBFAs) and applied them into sustainable concrete. It was found that the water absorption of CBFAs was between 12 and 14%, the bulk density was between 900 and 1100 kg/m3, and the compressive strength of single particle was greater than 1.8 MPa. And it was found that the mechanical strength and bulk density of CBFAs were positively correlated, while the mechanical strength and water absorption were negatively correlated. The leaching behaviors of CBFAs on Cu, Pb, Cd, and Cr were successfully suppressed to less than 1% of that originally from MSWIBA, which can be in line with the Chinese standards. Additionally, it is also found that the green concrete with adding GGBFS-CBFAs has higher overall fluidity and better mechanical properties than the concrete with FA-CBFAs. The mechanical properties of concrete were the best under the replacement rate of 60% of CFBAs, and the strength of green concrete added with GGBFS-CBFAs reached 96% of that of ordinary concrete. In this study, the rapid chloride ion penetration test, mercury intrusion and electron microscope tests found that the bonding effect between the CBFAs and the green concrete matrix was better, and the pore structure in the transition zone of the surrounding interface was refined. The proportion of transition pores in the pore structure was up to 59%. This shows that the concrete added with CBFAs has better resistance to chloride ion diffusion, and has some improvement on the durability. This research suggests that CBFAs including high volume MSWIBA has the potential to be successfully applied as the alternative to natural aggregates in sustainable concrete, and this can also advance waste recycling, and solidify high volume heavy metals in infrastructures.
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| 8. |
- Fan, Xing, 1975-, et al.
(författare)
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Guaranteed real-time services over standard switched Ethernet
- 2005
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Ingår i: The IEEE Conference on Local Computer Networks, 30th Anniversary. - New York, NY : IEEE Computer Society. - 0769524214 ; , s. 490-492
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Konferensbidrag (refereegranskat)abstract
- In this paper, we contribute with an approach to support guaranteed real-time services over standard switched Ethernet without additional hardware or software modification of the switch and the underlying standard. In our proposal, the traffic differentiation mechanism introduced by the IEEE 802.1D/Q standard and the standard hardware-implemented first come first served (FCFS) priority queuing are used in the switch and the source nodes. We have derived a feasibility analysis algorithm that can be used to ensure that the real-time requirements can be met. The algorithm also gives, as a sub-result, the needed buffer space in the end nodes and the switch. Moreover, our feasibility analysis supports variable-sized frames and switches with different bit-rates ports. The simulation analysis verifies our feasibility analysis.
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| 9. |
- Fan, Xing, 1975-, et al.
(författare)
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Efficient Many-to-Many Real-Time Communication Using an Intelligent Ethernet Switch
- 2004
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Ingår i: Proceedings of the 7<sup>th</sup> International Symposium on Parallel Architectures, Algorithms and Networks, 2004. - Piscataway, N.J. : IEEE. - 0769521355 ; , s. 280-287
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Konferensbidrag (refereegranskat)abstract
- This paper presents a solution for efficient many-to-many communication over switched Ethernet. The performance of using an ordinary switch and an intelligent switch is compared, and the results of the analysis based on 100 Mbit/s fast Ethernet show that an intelligent switch used to handle many-to-many communication can give better performance (shorter latency and higher utilization) than an ordinary switch. We also extend the network to serve many-to-many traffic with real-time demands by adding a thin software layer to the intelligent Ethernet switch and the end-nodes. Earliest deadline first (EDF) scheduling is used.
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| 10. |
- Fan, Xing, 1975-, et al.
(författare)
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Efficient Support for High Traffic-Volumes of Short-Message Real-Time Communication Using an Active Ethernet Switch
- 2004
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Ingår i: Proceedings of the 10th International Conference on Real-time and Embedded Computing Systems and Applications (RTCSA’04). ; , s. 517-533
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Konferensbidrag (refereegranskat)abstract
- There are several different types of communication traffic with real- time demands apparent in distributed industrial and embedded systems, for example, group communication and process synchronization. The length of these messages is often very short but the traffic volume might be really high. Standard network protocols do not normally reach very high utilization for such small messages. This paper presents a solution to efficiently support real-time short message communication over switched Ethernet. In our proposal, the Ethernet switch and the end-nodes are enhanced to combine several short messages into an Ethernet frame to improve the performance, and to give the short-message traffic real-time support on two levels, short-frame level and Ethernet frame level. Earliest Deadline First (EDF) scheduling is used in the switch and in the source nodes on both these two levels. We have characterized the performance of the network in terms of channel utilization and the number of accepted real-time channels, by simulations of the network assuming Fast Ethernet. We also show, by example, that we can reach an improvement of the possible short-message rate of 66%.
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