Mixed Materials Research Articles

A Comprehensive Review on Effects of Material Composition, Mix Design, and Mixing Regimes on Rheology of 3D-Printed Geopolymer Concrete

Recent years have witnessed a significant growth in the research and development of additive manufacturing methods involving concrete and cementitious materials, with technologies like three-dimensional (3D) printing becoming more widely used in the construction industry. Construction has the possibility to be revolutionized, not only in the context of cost savings but also in the context of increased sustainability and functionality. 3D printing of concrete is a cutting-edge technology that has the potential to speed up construction, reduce labor costs, give architects more creative freedom, improve precision, obviate requirements for formwork, and result in less construction wastes. In addition, 3D printing can be a long-term solution for both economy and environment. Even though 3D printing in concrete has made tremendous strides recently, developing an effective 3D-printable material that decreases material usage and enhances performance is critical for carbon dioxide reduction. Robust geopolymer formulations for 3D printing concrete technology in current construction applications have emerged as the subject of much research among scientists to find novel ways to circumvent this constraint. This study intends to highlight the current state of the art in developing 3D-Printed Geopolymer Concrete (3DPGC) with a comprehensive review related to the material composition, mix design, and mixing regimes on rheology of 3DPGC. The rheology of 3DPGC in terms of printability and buildability is discussed. The mixing regimes employed for the preparation of one-part and two-part 3DPGC are tabulated and commented on. Lastly, the research gaps are identified and summarized, and several research directions are also provided for future investigations to expedite the ubiquitous use of 3DPGC in versatile construction applications.

Hierarchically porous and single Zn atom-embedded carbon molecular sieves for H2 separations

Hierarchically porous materials containing sub-nm ultramicropores with molecular sieving abilities and microcavities with high gas diffusivity may realize energy-efficient membranes for gas separations. However, rationally designing and constructing such pores into large-area membranes enabling efficient H2 separations remains challenging. Here, we report the synthesis and utilization of hybrid carbon molecular sieve membranes with well-controlled nano- and micro-pores and single zinc atoms and clusters well-dispersed inside the nanopores via the carbonization of supramolecular mixed matrix materials containing amorphous and crystalline zeolitic imidazolate frameworks. Carbonization temperature is used to fine-tune pore sizes, achieving ultrahigh selectivity for H2/CO2 (130), H2/CH4 (2900), H2/N2 (880), and H2/C2H6 (7900) with stability against water vapor and physical aging during a continuous 120-h test.

Zircon and cassiterite geochronology of Sn-polymetallic pegmatite from the Xianghualing ore field, South China: Implications for multi-stage magmatic-hydrothermal events

The Nanling metallogenic belt (South China) is one of the largest W-Sn polymetallic provinces in the world. The ore bodies are mainly hosted in Triassic-Jurassic granitoids which formed during a complex history of magmatic evolution. Among them, the Laiziling pluton, which forms the northern part of the Xianghualing district, is an example of Sn-polymetallic deposits that underwent multiple Mesozoic episodes. In this study, the first in-situ U-Pb age dating of zircon and cassiterite minerals, trace element, and Lu-Hf isotopic data are reported for Laiziling NYF-type pegmatites. Four types of pegmatites are identified: stock-like pegmatite, vein-type pegmatite, peripheral vein-type pegmatite, and cap/sill-like pegmatite. Zircon LA-ICP-MS U-Pb geochronology of pegmatites yields an age of ~150 Ma, which is consistent with the age of the associated mineralized granitic pluton. Results of cassiterite age dating indicate that the W-Sn mineralization took place at ca. 150 Ma coeval with pegmatite emplacement. Combined with structure and trace element composition, two young ages (i.e., ~130 and 90 Ma) can be identified from pegmatite veins, suggesting that the studied zircon crystals experienced two distinct periods of magmatic-hydrothermal evolution during the Cretaceous (related to Late Yanshanian magmatism). In addition, some zircon grains are obviously enriched in LREE, which is associated with hydrothermal metasomatism. Compared to the narrow range of magmatic zircons, a wide range of inherited zircons (Proterozoic to Paleozoic) are observed in the studied Late Jurassic pegmatite (Pg1 and Pg2b), suggesting that they were incorporated from pre-existing basement rocks during magma ascent and/or emplacement. Furthermore, U-Pb data for 14 disseminated cassiterite grains yield a 206Pb/238U age of 221.5 ± 4.2 Ma, documenting evidence of cassiterite inheritance during melt ascension from country rocks or representing the initial stage of Sn enrichment. The εHf values of magmatic zircons show negative εHf values from −4.4 to −16.6 and their crustal model ages (TDM2) vary between 1328 Ma to 2200 Ma, suggesting the parent magma of the Laiziling pegmatites were derived from partial melting of older crustal components (Proterozoic basement in the Cathaysian Block of South China) and the mixing of mantle materials. This study proposes that multi-stage magmatic-hydrothermal events may have occurred not only in the Xianghualing area but also in the whole Nanling Range, and provides fresh insights into the formation processes of rare metal-bearing pegmatites in South China.

Study on dynamic mechanism of granular flow erosion and entrainment based on DEM theory

BackgroundGranular flows are common on the Qinghai–Tibet Plateau and the Hengduan Mountains in China, and their dynamic process processes have obvious erosional and entrainment effects. On the one hand, the volume of the granular flow increases by a factor of several or ten, which significantly increases its ability to cause a catastrophe; on the other hand, the eroded loose material affects the granular flow dynamics process and changes its state of motion.MethodsIn this paper, the dynamic mechanism of granular flow erosion and entrainment is investigated by DEM simulation.Purpose The effects of different substrate materials and substrate boundary conditions on granular flow erosion and entrainment are analyzed, and the effects of material mixing caused by erosion and entrainment on the state of motion of granular flow are discussed. It was verified that the kinetic mechanisms of granular flow erosion and entrainment includes impact erosion, ploughing, and shear abrasion.ResultsAnd discovered that small matrix particle size, small matrix boundary friction, and small matrix thickness lead to stronger ploughing and shear abrasion; Large matrix fractal dimensions result in stronger ploughing and weaker shear abrasion, and the granular flow does not entrain large amounts of material to the accumulation zone. Meanwhile, the dynamics of erosion and entrainment of granular flow were investigated, and the results showed that: 1. The greater the erosion rate, the greater the velocity and kinetic energy of the granular flow, the greater the distance traveled, and the smaller the apparent friction angle (i.e., the greater the mobility). 2. The amount of small granules in a granular flow changes its fluidity, the more small granules there are, the more fluid it is. 3. The fit reveals that the substrate fractal dimension has the strongest effect on the velocity and kinetic energy of granular flow, followed by substrate thickness and substrate boundary friction.

The effect of raw material (cow and chicken manure) and reactor type for improving and maximizing biogas production.

Biomass energy is a type of renewable energy and animal waste is one of the main resources for its production. The purpose of this study is to investigate the effect of raw material type (cow and chicken manure) and the type of reactor (digester) on the biogas produced by measuring the amount of methane in the product. Three types of digester (metal, simple PVC, and PVC with leachate rotation) with the same volume (10 L) were prepared. Equipment was installed on the digesters to measure the pH and volume of produced gas. The experiments were carried out in controlled temperature conditions (28-30 °C) and in two stages. The first experiment was to load the digesters with cow excrement, and the second experiment was to load the digesters with chicken excrement. In both experiments, the digesters were fed with 1.5 kg of animal manure and water with a ratio of 1:1. During a period of 60 days, the volume of biogas and methane produced was measured and recorded. The results showed that the amount of biogas produced from chicken waste is more than the amount obtained from cow waste. However, the amount of methane produced using cow excrement was more than that of chicken excrement. Also, the performance of PVC digester with leachate rotation was better than the other two digesters, which could be due to the mixing of raw materials in this type of digester.

Structural and performance variations of aluminoborosilicate glass substrates with mixed alkaline earth effect for applications in 3D integrated packaging

Alkali-free aluminoborosilicate glass substrates possess excellent chemical stability and outstanding thermodynamic and dielectric properties, rendering them promising candidates for applications in three-dimensional integrated packaging. This study investigates the structural and performance variations in RO (RBa,Sr)–Al2O3–B2O3–SiO2 glass substrates with a mixed alkaline earth effect under different BaO/SrO ratios (with a constant RO value of 20 mol%). The glass substrates were analyzed using various methods, including X-ray diffraction, differential scanning calorimetry, coefficient of thermal expansion, Raman spectroscopy, and 1 MHz–1 GHz dielectric property tests. Raman spectroscopy was used to measure the glass network connectivity using R12/34 (degree of [SiO4] units depolymerization) and N4 (degree of [BO4] units polymerization). The results show that the RABS15 sample had a significant reduction in dielectric loss at a frequency of 1 GHz compared with the other glass samples, corresponding to the best glass network connectivity. The main cause of high-frequency dielectric loss was the presence of [BO3] units in the glass network. During the preparation process, it was discovered that placing the crucible with mixed raw materials in an elevator-type furnace at a high temperature is an effective measure for solving the crystallization problem.

Utilization of Oil Palm Empty Fruit Bunch (EFB) Waste as a Mixing Material for In-terlocking Brick Production

The choice of building materials has a considerable influence on the reliability of a building. Conventional bricks, despite their frequent use, pose a challenge due to their weight, as they affect the load-bearing capacity of the building, unlike interlocking bricks, which have holes at the top and bottom for reinforcement, potentially reducing the effects of earthquakes. In this study, interlocking bricks made from a mixture of empty oil palm fruit stalks and sand with different sand replacements (0%, 2.5%, 5%, 7.5%, 10%, and 12.5%) are investigated. The research results consistently show that the average density of EFB fiber composite bricks with a density of 1.48 grams/cm³ is lower than that of standard composite bricks. Although the compressive strength of these bricks is initially lower than that of standard bricks, it increases with the substitution of part of the sand with EFB fibers, although not significantly, with the highest compressive strength observed at a substitution rate of 12.5%, reaching 5.201 MPa. Water absorption rates ranged from 13.97% to 21.99%, which increases compared to standard bricks but still meets the requirements. With ongoing research and innovation, EFB-based interlocking bricks have the potential to address environmental challenges and support sustainable and environmentally friendly building practices.

Critical Analysis of the practices of shop food handlers regarding safety and hygiene: Case study in Paranaque City

This study aims to analyze the knowledge, attitude, and practices of food handlers in milk tea shops inParanaque, Philippines, and identify areas for enhancing food safety and hygiene practices. A mixed-method approach was employed, with data gathered through a survey questionnaire and interviews with 100 milk tea shop food handlers. The study revealed that most food handlers (70%) were aged between 21 and 25 years old, with 92.9% female and 91.4% holding a college degree. Additionally, 85% of the respondents had prior experience in the food and beverage industry. However, only 57 outof the 100 respondents had registered their businesses. The food handlers demonstrated goodknowledge about food safety and sanitation, but some needed knowledge about proper food holding practices. Most food handlers had a positive attitude towards customers and food handling, but they needed to be more enthusiastic about securing business requirements due to perceived difficulties andexpenses. While 30% of the respondents emphasized the importance of avoiding cross-contaminationand 24% highlighted customer safety, only 44% had received formal training in proper food handling.The reasons for training included improving knowledge in food safety and hygiene practices (36%) and preventing foodborne illnesses and cross-contamination (18%).In terms of practices, the respondents needed better practices in storing, cooking, and cooling tapioca pearls, and often (4.05)mixed raw materials thoroughly using a shaker before serving due to limited staff and high pressure from customers to be served immediately. The study identified several challenges milk tea shop ownersface, including limited staff, space, cleanliness maintenance, and regulatory compliance complexities.These findings underscore the need for targeted training, operational support, and regulatory assistance to enhance food safety and operational efficiency in the milk tea industry.

The Vital Role of Libraries in Enriching Tourism Experiences

The article gives a detailed account on how libraries play a crucial role in enriching tourism. Libraries are key companions of tourists trying to delve into the places they visit. Through a mix of materials, services, programs and expert support, libraries allow tourist to relish the history, culture and attractions found at their destinations thus making travelling an enriching and memorable experience. With guidebooks and maps to digital archives and cultural events, there are many ways tourists can get involved with the world around them as they set off on meaningful journeys of discovery from one country to another. In addition to being custodians of knowledge and promoters of art, libraries enhance the quality of experiences in various parts of the world. By acknowledging the contribution that libraries make to tourism industry while backing its efforts towards educating office people who travel such as travelers that were engaged by it can help ensure that upcoming generations will still gain from this invaluable assistance made by them into traveling for future use.

Water-Soluble Reversible Photo-Cross-Linking Polymer Dielectrics.

Effective recycling of mixed materials requires the separation of the different components without the need for toxic solvents. One approach involves utilizing a water-soluble coating with reversible photo-cross-linkers, making it robust until end of life where it can then be dissolved in water after de-cross-linking. Here, a novel coumarin methacrylate monomer and its nitroxide-mediated copolymerization to create poly((methacrylic acid)-co-(styrene sulfonate)-co-(coumarin methacrylate)) for water-soluble thin films are reported. Under exposure to light, the coumarin functional groups produce reversible [2+2] cycloadditions which cross-link the resulting polymer films, making them no longer water soluble. Characterization of reversible cross-linking behavior is reported through changes in contact angle and in situ rheological characterization. The resulting polymers are successfully integrated into metal-insulator-metal capacitors, demonstrating the potential use for water-soluble reversible photo-cross-linkable dielectric materials for organic electronics.

Multi-staged ERO2.0 simulation of material erosion and deposition in recessed mirror assemblies in JET and ITER

The deposition/erosion on optical diagnostic components—mirrors—is a critical issue in reactor class devices with long-pulsed high fluence plasma operation. The paper presents results of the three-dimensional Monte–Carlo code ERO2.0 for two diagnostic aperture and first mirror geometries to be deployed in ITER, along with a separate simulation study that aims to replicate results from an experimental first-mirror study carried out on JET. Promisingly, very little plasma and impurity deposition on mirrors for the anticipated plasma durations is found in the ERO2.0 modelling taking into account the current ITER Research Plan and a material mix with beryllium first wall and a tungsten divertor. The post-mortem analysis of mirrors exposed during the experiment and the initial benchmarking efforts on the JET mirror experiment are also broadly consistent, increasing the confidence in predictions for ITER.

Effects of flows on transparent exopolymer particles released from branching Acropora coral colonies

Transparent exopolymer particles (TEP), a major component of coral mucus, are responsible for particle aggregation. These particles contribute substantially to the carbon cycle in coral reefs, and serve as an energy source for bacteria and other microorganisms. Water flows and induced turbulent mixing control material exchange between the coral canopy and the surrounding water, which is critical for coral health. However, how these factors affect TEP release by coral colonies has yet to be evaluated. Using a recirculating flume, we assessed TEP release by branching Acropora coral colonies and associated bacterial growth in the water column under different unidirectional flows. Changes in TEP and bacterial concentrations after 24-h incubation were quantified for flow speeds of 0, 5, 10, and 30 cm/s. Particle image velocimetry (PIV) measurements provided an estimate of turbulent mixing efficiency above the coral canopy. TEP and bacterial concentrations in the water column increased after 24 h of incubation. The increase in TEP and bacterial concentrations were 6.2–9.3 times and 3.4–5.1 times higher in the absence of flows, respectively, than mean values under water flows. Although mixing efficiency increased linearly with mean flow speeds, TEP release and bacterial growth differed only marginally at flows ranging from 5–30 cm/s. Detailed flow measurements combined with evaluation of TEP release suggest that the complex geometry of corals facilitates efficient material exchange at a range of flow speeds, and highlight the importance of considering these factors when estimating coral reef biogeochemistry.

Investigating Students’ Food Packaging-Related Challenges and Preferences in Europe and Asia

There is increasing pressure for everyone to adopt sustainable behaviours and typically this starts at-home via appropriate food-based disposal practices; however, this is associated with various barriers impacting compliance. Targeted education in college and/or the university environment could provide a viable approach to overcome such difficulties; yet, limited readily available resources exist to bring this forth. This paper explores students’ food packaging expectations and attitudes as well as information preferences in four countries (UK, France, India, and China). Students (n = 533) completed an online survey capturing food packaging purchase-based decisions, disposal-related challenges, and communication preferences. Students noted that food packaging had a dominant role in product choice. Fresh produce was considered an area for improvement, especially in the UK, India, and France, whereas snacks/baked goods were a priority in China. Disposal-related challenges were mostly associated with mixed materials. Students cited no clear information, limited choices, excessive packaging, and no nearby bins as common food packaging issues. This suggests that improving infrastructure (more bins, clearer signing) could be fundamental to encourage students to implement more sustainable food packaging behaviour. Furthermore, colleges and/or universities should consider students’ preferred information formats (infographics, videos) and develop targeted education (recyclability) which can be easily disseminated to promote engagement and sustainable food packaging knowledge and awareness.

Developing an orbitally shaken bioreactor featuring a square vessel wall with a large circular chamfer

The impact of orbitally shaking bioreactors (OSRs) on the biopharmaceutical industry is becoming increasingly important. In the preliminary exploration of the orbitally shaking bioreactor performance, the vessel wall shape has a crucial influence on the mixing and mass transfer in the bioreactor. However, the shape of OSRs still maintains a cylindrical structure, significantly limiting the advantages of the orbital shaking mixing. Therefore, in order to further improve the mixing and mass transfer performance of OSRs, a novel wall shape is proposed in this paper. This novel wall shape consists of cylindrical and square parts and looks like a square tank with a large circular chamfer (STCC), which was found could effectively enhance the efficiency of material mixing and mass transfer theoretically. Based on the same specific volumetric power consumption, a comparative analysis was conducted on the mixing time and oxygen transfer efficiency of OSRs with different shape walls using simulation and experimental methods. The results showed that the OSR with STCC was expected to perform higher mixing and oxygen transfer efficiency than the OSR with cylindrical wall. These findings suggested a promising prospect for the future application of the OSRs with STCC.

The Effect of Cesium Incorporation on the Vibrational and Elastic Properties of Methylammonium Lead Chloride Perovskite Single Crystals.

Hybrid organic-inorganic lead halide perovskites (LHPs) have emerged as a highly significant class of materials due to their tunable and adaptable properties, which make them suitable for a wide range of applications. One of the strategies for tuning and optimizing LHP-based devices is the substitution of cations and/or anions in LHPs. The impact of Cs substitution at the A site on the structural, vibrational, and elastic properties of MAxCs1-xPbCl3-mixed single crystals was investigated using X-ray diffraction (XRD) and Raman and Brillouin light scattering techniques. The XRD results confirmed the successful synthesis of impurity-free single crystals, which exhibited a phase coexistence of dominant cubic and minor orthorhombic symmetries. Raman spectroscopy was used to analyze the vibrational modes associated with the PbCl6 octahedra and the A-site cation movements, thereby revealing the influence of cesium incorporation on the lattice dynamics. Brillouin spectroscopy was employed to investigate the changes in elastic properties resulting from the Cs substitution. The incorporation of Cs cations induced lattice distortions within the inorganic framework, disrupting the hydrogen bonding between the MA cations and PbCl6 octahedra, which in turn affected the elastic constants and the sound velocities. The substitution of the MA cations with smaller Cs cations resulted in a stiffer lattice structure, with the two elastic constants increasing up to a Cs content of 30%. The current findings facilitate a fundamental understanding of mixed lead chloride perovskite materials, providing valuable insights into their structural and vibrational properties.

Inkjet-printed waveguide-coupled passive wedge-shaped microdisk resonator with refractive index tunability

We incorporate a passive wedge-shaped organic microdisk supporting spatially separated whispering gallery modes into an SU-8 photonic integrated circuit (PIC) by using direct inkjet printing. This innovative method allows the mixing of multiple organic materials, enabling tunability of the refractive index of microdisks, thereby overcoming limitations of single-material resonators from conventional lithography. In this study, the microdisk resonator, with a refractive index matching that of SU-8 by mixing hyperbranched polymers, is mounted horizontally to an optical waveguide, achieving directional coupling between the microdisk and PIC at a wavelength of 1550 nm. Geometrical conditions for successful coupling were obtained by measuring the cross-sectional profile of the fabricated structure’s surface via atomic force microscopy, determining ways to adjust the coupling efficiency.

Evaluation of the Energy Efficiency of the Process of Vibratory Mixing of Multicomponent Bulk Raw Material of Food Industries

Evaluation of the Energy Efficiency of the Process of Vibratory Mixing of Multicomponent Bulk Raw Material of Food Industries

Inhibition of acid rock drainage with iron-silicate or phosphate film: in rainy and submerged environments.

Iron phosphate-based coating and iron silicate-based coating were used to inhibit the oxidation of sulfide minerals in rainy and submerged environments. The inhibiting effectiveness of coating agents on the oxidation of iron sulfide minerals was investigated using pyrite and rock samples resulting from acid drainage. The film formed with both surface-coating agents was identified by pyrite surface analysis. It was also confirmed that the formation of coatings varies depending on the crystallographic orientation. The inhibitory effects under rainy and submerged conditions were investigated using column experiments. Submerged conditions accelerated deterioration compared to that under rainy conditions. Iron phosphate coating had a significantly better oxidation-inhibitory effect (84.86-98.70%) than iron silicate coating (56.80-92.36%), and at a concentration of 300mM, H+ elution was inhibited by more than 90% throughout the experiment. Furthermore, methods for effective film formation were investigated in terms of producing Fe3+; (1) application of coating agents mixed with oxidant (H2O2), (2) application of coating agent after the use of the oxidant. In a rainy environment, applying iron phosphate-based coating using the sequential method showed oxidation inhibition effects for cycles 1-9, whereas applying the mixed material showed effects for cycles 9-13. The use of a surface-coating agent after applying an oxidant did not inhibit oxidation. The surface coating agent and the oxidizing agent should be applied as a mixture to form a film.

Pb Isotope Signature of a Low-μ (238U/204Pb) Lunar Mantle Component

Abstract The chemical and isotopic characteristics of terrestrial basalts are constrained within the concept of mantle chemical geodynamics that explains the existing variety of basaltic rocks within a framework of several end-member reservoirs in Earth’s mantle. In contrast, there is no comparable fully developed model explaining the isotopic composition of lunar basaltic rocks, in part owing to the lack of well-constrained age–isotope relationships in different groups of basalts identified on the Moon. Notably, the absence of agreement upon ages includes basalts from a unique group of meteorites collectively known as ‘YAMM’ (basalts Yamato-793169: Y-793169, Asuka-881757: A-881757, Miller Range 05035: MIL 05035 and regolith breccia Meteorite Hill 01210: MET 01210), which appear to show chemical signatures different from all other known lunar basaltic rocks. We present high-precision Pb–Pb ages and initial Pb isotopic ratios for two samples from this group, MIL 05035 and A-881757. These meteorites have Pb isotope ratios different from those of the other lunar basalts, suggesting they are derived from a distinct and depleted mantle source, with a 238U/204Pb ratio (μ value) lower than any other mantle source. Their depletion in rare earth elements, in conjunction with recalculated initial Nd and Sr isotopic ratios from published data and using our new age, appear to support this conclusion. The chemical and Sr-Nd-Pb isotopic characteristics of this low-μ source appear to be the opposite of those of the KREEP reservoir and many, if not all, features described in other lunar basalts (such as low- and high-Ti mare basalts) can be explained by a binary mixing of material derived from low-μ and KREEP-like reservoirs. This mixing might be the result of a slow, convection-like mantle overturn.

Investigations on the turbulentnon-turbulent interface in supersonic compressible plate turbulent boundary layer

The turbulent boundary layer (TBL) is a widely existing flow phenomenon in nature and engineering applications. Its strong mixing effect can achieve more sufficient material mixing, heat transport, etc. The understanding of the entrainment process and mechanism of irrotational fluids entering the turbulent region can be promoted by studying the geometric and dynamic characteristics of turbulent ${/}$ non-turbulent interfaces (TNTI). In compressible flow, it is unclear whether the properties of TNTI will change and whether the entrainment will show different features due to the influence of compressibility. Based on the direct numerical simulation results of supersonic compressible plate TBLs with Mach number of 2.9, the geometric and dynamic characteristics of TNTI are investigated in this paper. The interface is identified by the enstrophy method, and the height, thickness, fractal dimension, enstrophy transportation and entrainment characteristics of the interface are investigated. It is found that for the enstrophy transportation in a TBL, the contribution of compressibility-related terms accounts for approximately 13.4 % of the total enstrophy transportation, which tends to transfer the enstrophy of turbulence near the interface to both directions vertical to the interface. This promotes the expansion of the turbulent region towards the non-turbulent region, and the mean height, thickness and entrainment velocity are increased by approximately 3.7 %, 7.0 % and 8.5 %, respectively, while the fractal dimension is basically unaffected. Different from the incompressible flow, the contribution of the compressibility-related terms to the entrainment velocity is independent of the local curvature, and the intense entrainment process is more likely to occur on a highly curved concave surface.