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•Cellular ceramic structures have been extensively applied in catalysis supports, concentrated solar energy, thermal protection or thermal storage, heat exchangers, radiant burners, ...nuclear fusion, gas streams, and biomedical implants.•Additive manufacturing technologies based on stereolithography, extrusion free-forming, two-photo lithography have been extensively adopted to fabricate cellular ceramic structures.•Structural additively manufactured cellular ceramic lattices, as well as structure–function integrated additively manufactured cellular ceramic lattices, were comprehensively summarized.•Smart and flexible cellular ceramic structures may be the future trend in this field.
Cellular ceramic structures (CCSs) have promising application perspectives in various fields. Recently, additive manufacturing (AM), usually known as three-dimensional printing (3D printing), has been increasingly adopted to produce CCSs. Usually, the structural properties of additively manufactured cellular ceramic structures (AM-CCSs), i.e., lightweight characteristics, load-bearing capacity, toughness, unconventional properties, are traditionally investigated. Interestingly, AM technologies have a significant advantage in achieving the structure–function integration for CCSs. Functional properties, e.g., electromagnetic property, acoustic property, thermal property, of CCSs can be achieved during the structural design synchronously. In this review, firstly, the AM technologies for CCSs are comparatively introduced. Then, structural AM-CCSs are summarized. After that, structure–function integrated AM-CCSs are further introduced in detail. Finally, challenges and opportunities towards structure–function integrated AM-CCSs are forecasted. This review is believed to give some guidance for the research and development of CCSs.
Stereolithography based additive manufacturing provides an effective method to fabricate complex-shaped SiC ceramic components. The dispersion and stability of the ceramic slurry are very important ...for stereolithography. In this study, the dispersion and stability of SiC ceramic slurries were investigated systematically. The effects of resin monomers, dispersants, particle size, solid loading and ball milling time on the dispersion, rheological behavior and stability of SiC ceramic slurries were studied in detail. Finally, an optimal SiC ceramic slurry for stereolithography based additive manufacturing was obtained, and complex-shaped SiC ceramic architectures were fabricated.
Photosensitive Al2O3-resin slurries with high solid loading, low viscosity used for stereolithography based additive manufacturing were prepared in this paper. The dispersion behavior and rheological ...behavior of the Al2O3-resin slurries were studied by rheology observation and sedimentation tests. The dispersant type, concentration and solid loading had significant effects on the rheological behavior and stability of the photosensitive Al2O3-resin slurries. A long term stability and homogeneity slurry was obtained when the dispersant and concentration were KOS110 and 5 wt%, respectively. The Al2O3 slurry prepared with a high solid loading up to 60 vol%, low viscosity of 15.4 Pa s at 200 s−1 was chosen for stereolithography based additive manufacturing.
Silicon carbide (SiC) ceramic and related materials are widely used in various military and engineering fields. The emergence of additive manufacturing (AM) technologies provides a new approach for ...the fabrication of SiC ceramic products. This article systematically reviews the additive manufacturing technologies of SiC ceramic developed in recent years, including Indirect Additive Manufacturing (Indirect AM) and Direct Additive Manufacturing (Direct AM) technologies. This review also summarizes the key scientific and technological challenges for the additive manufacturing of SiC ceramic, and also forecasts its possible future opportunities. This paper aims to provide a helpful guidance for the additive manufacturing of SiC ceramic and other structural ceramics.
The application of livestock manure increases the dissemination risk of antibiotic resistance genes (ARGs) in farmland soil environment. However, the vertical migration behavior and driving factor of ...ARGs in manured soil under swine manure application remains undefined. Here, the dynamics of ARGs, mobile genetic elements (MGEs) and bacterial communities in different soil depths (0 – 80 cm) with long-term swine manure application were tracked and conducted using real-time qPCR. Results showed that long-term application of swine manure remarkably facilitated the vertical accumulation of ARGs and MGEs, in particular that the relative abundance of blaampC showed significant enrichment with increasing depth. ARGs abundance was similar in the three fields with long-term application of swine manure. (p＞0.05). Procrustes analysis indicated that microbial communities were the dominant drivers of ARGs variation in topsoil, and the changes of environmental factors played a vital role in vertical migration ARGs in cropland soils. Additionally, the variation patterns of high-risk ARGs (i.e., blaampC, blaTEM-1) were influenced by the dominant bacteria (Actinomycetes) and pH. This study illustrated that the swine manure application promoted the vertical migration of ARGs, including multidrug resistance determinants, highlighting the ecological risk caused by long-term manure application.
•This study addressed the vertical migration patterns of ARGs in cropland.•Long-term manure application promoted the accumulation of high-risk ARGs.•ARGs in relative abundance showed an enrichment trend with soil depth.•Bacterial communities were the dominant drivers of ARGs variation in topsoil.•Soil properties had more significant effect on ARGs with increase of soil depth.
Ceramic lattice structures (CLSs) are promising candidates for structural applications used in conventional and extreme environments because of their extraordinary properties. Herein, CLSs with ...different structural configurations, including body-centred cubic (BCC), Octet, and modified body-centred cubic (MBCC), were designed and fabricated by digital light processing (DLP)-based additive manufacturing technology to explore their quasi-static and dynamic compressive behaviours. It was demonstrated that when relative density was a constant, quasi-static compressive strength (QS), quasi-static Young's modulus (QY), and quasi-static energy absorption (QE) of CLSs with an MBCC structural configuration were the best, Octet ranked secondly, BCC was the poorest. The same thing happened on dynamic mechanical properties of CLSs. Increasing the relative density from 20% to 40% dramatically improved the QS, QY, and QE of CLSs. Furthermore, it was revealed by experiment and simulation that the quasi-static failure mode of CLSs changed from partially fracture along a specific plane to integrally fracture at most nodes as relative density increased. Furthermore, the dynamical mechanical properties of CLSs were significantly outstanding than quasi-static mechanical properties due to the strain-rate effect. This study provides a new basis for further study on tailoring the mechanical properties of CLSs.
In this study, the influence of NaOH and thermal pretreatment of dewatered activated sludge (DAS) on the high-solid solubilisation and anaerobic digestion was separately investigated by monitoring ...common parameters. The results indicated that COD, proteins and carbohydrates were efficiently solubilised in both NaOH and thermal pretreated DAS samples. For NaOH pretreatment, the concentrations of volatile fatty acids (VFAs) and total ammonium nitrogen (TAN) firstly increased followed by decreasing with NaOH dose increasing. However, they decreased with the severity of thermal pretreatment. During the batch digestion experiments (at 37°C), for 80mg NaOHg(-1) total solid (TS) DAS pretreatment it resulted in a 6.99% decrease in cumulative methane yield (CMY) compared to untreated DAS. While for 80, 100, 120°C and 20mg NaOH pretreatment, CMY increased by 15%, 42%, 71% and 35%, respectively, in comparison to untreated DAS.
The stereolithography additive manufacturing is reported to fabricate ZrO2 ceramic components with complex-shapes for various military and engineering applications recently. Investigations show that ...the solid loading of the ceramic suspension exhibits significant influence on the properties of stereolithography additive manufactured ZrO2 ceramic. However, the intrinsic relationships between the solid loading of the ZrO2 suspension and the relative density, microstructure, mechanical and other properties of the ZrO2 ceramic have not been investigated systematically. In this study, the roles of solid loading in stereolithography additive manufacturing of ZrO2 ceramic were discussed in detail. Firstly, the rheological property, curing behavior of the ZrO2 suspensions with different solid loading were studied, and the stereolithography additive manufacturing was subsequently conducted. After that, the effects of the solid loading on the phase composition, relative density, mechanical property, microstructure, coefficient of thermal expansion (CTE), and shrinkage of the as-prepared ZrO2 ceramic were studied in-depth. The relationship between the solid loading of the ZrO2 suspension and the properties of the ZrO2 ceramic were successfully revealed. At last, ZrO2 ceramic components with good shape stability, high precision, and high performance were obtained. It is believed that this paper can give a deep understanding of the stereolithography additive manufacturing of ceramics.
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•Roles of solid loading in photosensitive ZrO2 suspensions were revealed.•Relationship between solid loading and properties of ZrO2 ceramic were illustrated.•Nano X-CT was employed to detect the internal features.•Accurate prediction and control of the final ceramic product dimensions were achieved.
Using cow dung to breed earthworms poses a risk of environmental transmission of antibiotic resistance genes (ARGs). The purpose of this study was to address the occurrence, persistence and ...environmental fate of ARGs during earthworm conversion of cow dung. The results showed that ARGs persisted through the whole process. Notably, earthworm conversion effectively reduced some ARGs in cow dung, but a definite concentration of ARGs still remained in earthworms and vermicompost (up to 10-1 and 10-2 copies/16S copies, respectively). We found that tet-ARGs were the most abundant in 15 earthworm farms (10-6~10-1 copies/16S copies) and some high-risk ARGs (i.e., blaampC, blaOXA-1 and blaTEM-1) were even prevalent in these farms. Interestingly, although ARGs differ widely in cow dung (10-10~10-1 copies/16S copies), the ARGs levels were comparable in vermicompost samples from different farms (10-8~10-2 copies/16S copies). Notably, earthworm conversion effectively reduced some ARGs in cow dung, but significant level of ARGs still remained in earthworms and vermicompost (up to 10-1 and 10-2 copies/16S copies, respectively). Nevertheless, the concentrations of some heavy metals (Cu, Zn and Ni), the abundance of mobile genetic elements (MGEs) and total nitrogen content were confirmed to be correlated to the enrichment of some ARGs. Overall, this study demonstrated the high prevalence of ARGs contamination in earthworm farms, and also highlighted the dissemination risk of ARGs during the earthworm conversion of cow dung.
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•This paper showed the prevalence of ARGs in earthworm conversion of cow dung.•We first confirmed the risk of ARGs spread by using cow dung to feed earthworms.•Earthworm conversion reduced the diversity and abundance of ARGs in cow dung.•Earthworm conversion eliminated the difference of ARGs in different cow dung.
The overuse or abuse of antibiotics as veterinary medicine and growth promoters accelerates antibiotic resistance, creating a serious threat to public health in the world. Swine liquid manure as an ...important reservoir of antibiotic resistance genes (ARGs) has received much attention, but little information is known regarding the occurrence, persistence and fate of ARGs-associated mobile genetic elements (MGEs) in swine farms, especially their change patterns and removal in full-scale piggery wastewater treatment systems (PWWTSs). In this study, we searched the presence and distribution of MGEs and associated ARGs in swine farms, and addressed their fate and seasonal variation in full-scale PWWTSs by real-time quantitative PCR (qPCR). Our results revealed class 1 integrons, class 2 integrons and conjugative plasmids were prevalent in pig feces and piggery wastewater. A clear pattern of these MGE levels in swine liquid manure was also observed, i.e., intI1 > intI2 > traA (p < 0.01), and their absolute abundances in winter were all higher than that in summer with 0.07-2.23 logs. Notably, MGEs and ARGs prevailed through various treatment units of PWWTSs, and considerable levels of them were present in the treated effluent discharged from swine farms (up to 10
-10
copies/mL for MGEs and 10
-10
copies/mL for ARGs). There were significant correlations between most ARG abundance and MGE levels (p < 0.05), such as tetQ and traA (r = 0.775), sul1 and intI1 (r = 0.847), qnrS and inI2 (r = 0.859), suggesting the potential of ARGs-horizontal transfer. Thus the high prevalence and enrichment of MGEs and ARGs occurred in pig feces and piggery wastewater, also implicating that swine liquid manure could be a hotspot for horizontal transfer of ARGs.
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