Secondary Aggregation Research Articles

Dual Thermo- and pH-Responsive N-Cyanomethylacrylamide-Based Nano-Objects Prepared by RAFT-Mediated Aqueous Polymerization-Induced Self-Assembly

We report the straightforward synthesis of dual stimuli-responsive nano-objects using a RAFT-mediated polymerization-induced self-assembly process in water. The key to complex and tunable responsiveness was the copolymerization of N-cyanomethylacrylamide, providing upper critical solution temperature-type polymers, with a pH-sensitive monomer (acrylic acid, AA). Not only the core block length but also the AA content and slight changes in the degree of ionization of AA in the polymerization medium (αAA,0) had a great impact on the particle morphology. Generally, higher AA contents favored the formation of spherical nano-objects, while low αAA,0 led to higher-order morphologies. We demonstrated that the nano-objects exhibited a complex dual responsiveness to changes in the degree of ionization and temperature. Progressively increasing post-polymerization the degree of ionization of the AA units incorporated in the copolymer (αAA) triggered morphological transitions. Remarkably, a single copolymer composition formed well-defined vesicles, worms, and spheres that eventually dissociated into individual chains. Temperature-dependent small-angle X-ray scattering analyses evidenced a complex thermo-responsive behavior, which depended on the copolymer composition and αAA. For some compositions, we observed both a cloud point and a clearing point, attributed to the formation of secondary aggregates and chain dissolution, respectively.

The molecular interaction of three haloacetic acids with bovine serum albumin and the underlying mechanisms

As typical disinfection byproducts, monohaloacetic acids (monoHAAs) were reported to be cytotoxic and genotoxic with the order of iodoacetic acid (IAA) > bromoacetic acid (BAA) ≫ chloroacetic acid (CAA). However, it remains unknown for the toxicity of monoHAAs to biomacromolecules and the detailed molecular mechanisms. Consequently, the structural and functional responses of bovine serum albumin (BSA) to three monoHAAs (CAA, BAA and IAA) were compared by investigating their interactions using multi-spectroscopic methods, esterase-like activity assays and molecular docking simulations. Results found that monoHAAs stimulated the esterase-like activity of BSA to different levels with the order of CAA > IAA > BAA. The binding of monoHAAs affected the secondary structures, peptide skeleton and aggregation state of BSA. The interactions of BSA with CAA, BAA and IAA are dominated by van der Waals forces and hydrogen bonds, hydrophobic forces and electrostatic forces, respectively. The binding of CAA directly interferes the key residues Arg 254 and Tyr 147 to the activity but BAA and IAA do not. BAA and IAA interacted with Tyr residues by static and dynamic quenching, respectively. The binding constant suggested a relatively weak binding affinity for the interaction of BSA with BAA and with IAA. While CAA barely changed the fluorescence of BSA with the increase of exposure concentrations. Accordingly, this study provides a comprehensive view on the molecular toxicity of monoHAAs interacting with BSA.

Analysis of types of technologies for the processing of building materials by carbon footprint indicators

With the increase in the rate of civil construction and the growth of socio-economic development, there is a significant increase in the consumption of construction materials based on natural raw materials, which makes research in the search for an alternative raw material base for the construction industry as a whole relevant. Rational solution in terms of ecology and economy becomes the recycling of construction materials and the use of industrial waste. The trend of using construction waste as aggregates for concrete products and structures, is currently the most effective solution to reduce the negative impact on the environment, and also has a number of economic advantages, when choosing the optimal processing technology. This article considers the state, trends and problems of development of the construction sector of the economy in the direction of energy-efficient technologies and principles of sustainable development that help to reduce the negative impact of the construction sector on the environment in urban conditions. The main reasons for the increased interest in the research of environmentally friendly methods of recycling construction materials are indicated. The characteristics and unique properties of raw materials subjected to various methods of recycling are described. The advantages offered by the innovative system of "green" construction with the introduction of construction waste recycling technologies are given. The authors present an analysis of the most common technologies and methods of recycling concrete scrap into secondary aggregate, as well as the advantages and disadvantages of each method of regeneration of concrete scrap. The experience of researches of innovative methods of recycling concrete in foreign countries, the prospects and problems of further development of "green" technologies in the Russian building industry, and also priorities and prospects for entering the market of domestic producers of concrete products on the basis of secondary aggregate, which will allow to provide decrease in extraction and production of natural raw materials are revealed. Formulated further research directions of the problems of development of green technologies in the construction sector of the economy.

Organic matter governs weathering rates and microstructure evolution during early pedogenesis

Soil aggregation and the translocation of clay and organic matter are significant pedogenic processes that manifest in diagnostic horizons in mature soil. Yet, their onset might date to much earlier stages of soil development where host rock weathering is dominant and litter from pioneer vegetation is the only input of organic matter. We present a time-lapse experimental-pedogenesis study on early host rock weathering that shows the formation of aggregates and clay translocation in response to irrigation with and without organic matter released from a litter layer. The presence of organic matter increases total carbonate dissolution capacity and results in a characteristic surface morphology, while simultaneously slowing down the dissolution rate. With the dissolution of carbonates, clay minerals of the host rock and iron from pyrite are released. Controlled by the presence of organic matter, both are either transported with the seepage water or form crusts and aggregates from clay minerals and freshly precipitated secondary iron oxides. Our study shows that the interplay of dissolution, neoformation of secondary minerals, translocation, and aggregation of organic matter and clay-sized minerals shape soil structure evolution during early pedogenesis in carbonate host rocks.

Adenylate cyclase A amplification and functional diversification during Polyspondylium pallidum development

BackgroundIn Dictyostelium discoideum (Ddis), adenylate cyclase A (ACA) critically generates the cAMP oscillations that coordinate aggregation and morphogenesis. Unlike group 4 species like Ddis, other groups do not use extracellular cAMP to aggregate. However, deletion of cAMP receptors (cARs) or extracellular phosphodiesterase (PdsA) in Polyspondylium pallidum (Ppal, group 2) blocks fruiting body formation, suggesting that cAMP oscillations ancestrally control post-aggregative morphogenesis. In group 2, the acaA gene underwent several duplications. We deleted the three Ppal aca genes to identify roles for either gene and tested whether Ppal shows transient cAMP-induced cAMP accumulation, which underpins oscillatory cAMP signalling.ResultsIn contrast to Ddis, pre-aggregative Ppal cells did not produce a pulse of cAMP upon stimulation with the cAR agonist 2′H-cAMP, but acquired this ability after aggregation. Deletion of Ppal aca1, aca2 and aca3 yielded different phenotypes. aca1ˉ cells showed relatively thin stalks, aca2ˉ showed delayed secondary sorogen formation and aca3ˉ formed less aggregation centers. The aca1ˉaca2ˉ and aca1ˉaca3ˉ mutants combined individual defects, while aca2ˉaca3ˉ and aca1ˉaca3ˉaca2ˉ additionally showed > 24 h delay in aggregation, with only few aggregates with fragmenting streams being formed. The fragments developed into small fruiting bodies with stalk and spore cells. Aggregation was restored in aca2ˉaca3ˉ and aca1ˉaca3ˉaca2ˉ by 2.5 mM 8Br-cAMP, a membrane-permeant activator of cAMP-dependent protein kinase (PKA). Like Ddis, Ppal sorogens also express the adenylate cyclases ACR and ACG. We found that prior to aggregation, Ddis acaˉ/ACG cells produced a pulse of cAMP upon stimulation with 2′H-cAMP, indicating that cAMP oscillations may not be dependent on ACA alone.ConclusionsThe three Ppal replicates of acaA perform different roles in stalk morphogenesis, secondary branch formation and aggregation, but act together to enable development by activating PKA. While even an aca1ˉaca3ˉaca2ˉ mutant still forms (some) fruiting bodies, suggesting little need for ACA-induced cAMP oscillations in this process, we found that ACG also mediated transient cAMP-induced cAMP accumulation. It, therefore, remains likely that post-aggregative Ppal morphogenesis is organized by cAMP oscillations, favouring a previously proposed model, where cAR-regulated cAMP hydrolysis rather than its synthesis dominates oscillatory behaviour.

The primary and secondary mineral resources of Montenegro and their mapping into the European data model

Primary and secondary mineral resources are of strategic importance to the EU economy. Montenegro, as a country candidate for membership in the EU, is required to follow (and later to implement) European policies, strategies as well as initiatives, including those related to mineral resources and the mining sector. The importance of providing access to mineral raw materials in the future is recognized by the EU, as well as meeting the needs of European industry, maintaining employment and ensuring further development. Considering the overall economic situation in Montenegro, it is important to encourge the mining sector and other industries based on the use of mineral resources in making a greater contribution to the development and sustainability of society as a whole and also increase the share of national GDP. The potential for discovery and utilization of primary and secondary mineral resources in Montenegro is demonstrated. The most important metallic mineral resources are bauxite, lead and zinc, while conventional energy resources include coal (oil and gas potential has yet to be proven). In addition, there are abundant non-metallic mineral raw materials - industrial minerals and construction materials. Secondary mineral resources, especially aluminous red mud (bauxite residue), are also significant and have been the subject of research in recent years. Tailings from flotation processes at operating and abandoned lead and zinc mines might also be of interest for metal recovery. Bottom and flay ash from thermal power plants, slag from steel production, as well as marlstone and limestone from the hanging wall of coal deposits may also have potential. Waste rocks could be used particularly for secondary aggregate production. A database was developed and the most important deposits of primary and secondary mineral resources in Montenegro were mapped during the RESEERVE project. Mineral data were harmonised so as to be INSPIRE compliant. In addition, some novel geochemical exploration results of secondary mineral resources are presented.

Effects of secondary soil aggregates on threshold friction velocity and wind erosion

AbstractSecondary aggregates (clods) attenuate wind erosion and land degradation by increasing surface roughness and reducing wind friction velocities at the soil surface. However, aggregates with low stability are erodible and may increase dust emissions by particle abrasion under saltation bombardment relative to non‐erodible aggregates. It is still not clear exactly how different secondary aggregate properties reduce, and in the presence of saltators potentially increase, wind erosion and dust emission. The objective of this study was to quantify the effects of erodible soil aggregates on the threshold friction velocities (u*t), aerodynamic roughness length (zo), and soil loss of loessial soils in the inland Pacific Northwest (iPNW) of the United States. The impact of erodible secondary aggregates in attenuating wind erosion was evaluated in terms of secondary aggregate lateral cover and density. Secondary aggregates were tested in a wind tunnel using five levels of aggregate densities. Secondary aggregates appeared to restrain wind erosion as z0 and u*t increased with increasing aggregate cover, but may significantly change wind erosion patterns by releasing more fine dust particles by abrasion. We found that, while abrasion losses contributed up to 69.3% of total soil loss for a sandy loam, total soil loss still decreased for all soils. Aggregates with greater stability may reduce soil loss with increasing secondary aggregate densities, and the rate of reduction in soil loss was up to two times higher than that for soil aggregates with lower stability.

A green dual-phase carbon-silica nanohybrid derived from black liquor lignin for reinforcing styrene-butadiene rubber

In rubber industry, lignin has been investigated as a potential alternative of fossil-derived carbon black (CB) for several decades. However, due to poor dispersity, big particle size and incompatibility with rubber, lignin cannot achieve the same reinforcing effect as CB by direct dry mixing. Here, a new and green dual-phase carbon-silica nanohybrid (LDPCS) was successfully prepared from black liquor lignin (BLL) and sodium silicate through a simple co-gelation/self-assembly and carbonization process. The preparation mechanism and process as well as the morphology and properties of LDPCS were investigated and discussed in detail. The results indicated that the hydroxymethylation and silane modification of BLL could improve its affinity with SiO2 sols, thus facilitating the co-gelation of BLL and SiO2 sols to inhibit the growth of SiO2 particles. During subsequent acid precipitation, silane modified hydroxymethylated BLL (SiHM-BLL) was self-assembled around SiO2 particles to form nanosized SiHM-BLL-SiO2 hybrids. After carbonization, SiHM-BLL-SiO2 nanohybrids were converted into LDPCS with small primary particle size of 60–90 nm, high specific surface area of 82.19 m2/g, relatively loose secondary aggregation structure and graphitic microcrystals in the carbon framework. With incorporating LDPCS into styrene-butadiene rubber (SBR) by direct dry mixing, LDPCS showed a superior reinforcing capability for SBR as compared with CB, which was ascribed to the nanoscale dispersion of LDPCS, robust C/SiO2 interfaces and high affinity with SBR matrix. This work provided a new insight into the fabrication of novel hybrid nanofiller from lignin and broadened the potential applications of lignin in rubber compounds and beyond.

Effect of parent concrete strength on recycled concrete performance

The reuse of concrete waste as a secondary aggregate could be an efficient solution for sustainable development and long-term environmental protection. However, the variable quality of waste concrete, especially with various compressive strengths, can have a negative effect on the final compressive strength of recycled concrete. In this approach, the major goal of this research is to study the effect of parent concrete qualities on the performance of recycled concrete. To accomplish this task, three grades of different compressive strengths (10 to 15) MPa, (20 to 25) MPa, and (30 to 40) MPa have been analyzed in an experimental test program, in which an unknown compressive strength is introduced as well. The experimental mix use 40% of secondary aggregates (both course and fine) and 60% of natural aggregates. This led to the decreasing of the compressive strength of the test concrete between 14% and 23.7% compared to the normal concrete. This loss was improved by adding an amount of cement equivalent to 4% of the weight of the recycled aggregate used. The achieved results prove that the strength properties of the parent concrete have a limited effect on the compressive strength of the recycled concrete. Additionally, low compressive strength parent concrete, when crushed, generates a high amount of fine aggregate and large percentage of recycled coarse aggregates with less attached mortar, and presents the same compressive strength as an excellent parent concrete.

Market prospects of secondary construction aggregates in Sweden

The transition towards a circular economy is being increasingly envisaged in Europe. Increased utilisation of secondary construction aggregates poses a great opportunity in this regard given its potential to avoid waste disposal, natural resource extraction, and reduce costs. Nevertheless, the Swedish construction aggregates market is dominantly characterised by primary aggregates utilisation. This study employs a qualitative approach to analyse the Swedish construction aggregates market from the user perspective in order to identify the challenges of increased utilisation of secondary aggregates. The dominant and systematic utilisation of primary aggregates is chiefly driven by market processes allowing economic advantages and convenience for the users in doing so, whereas the situational and non-systematic utilisation of secondary aggregates is opportunistically driven by different actors in order to seize opportunities such as avoided costs and improved environmental performance. The realisation of increased secondary aggregates utilisation needs to be first facilitated via changes to the institutional structure that makes such materials a priority issue for the supply chain actors, which necessitates national-level policy interventions and supply chain actor collaborations. Second, the competitiveness of secondary aggregates needs to be lifted to a comparable state to that of primary aggregates, which necessitates the development of specific sectoral application standards and vertical integration of secondary aggregates supply by construction corporations.

High-solid content, low viscosity and long-term stability Mn–Co–Ni–O ceramic slurry for the fabrication of free-standing ultrathin NTC sheets

This study systematically investigated the relationships between Mn–Co–Ni–O ceramic slurry formulations and their volatility, rheology and stability, as well as the electrical properties of free-standing ultrathin sheets made from them. A ceramic slurry with a high solid content of 90%, viscosity <12,000 mPa s, and 720 h long-term stability was successfully obtained by optimizing a spherical clusters powder and organic carrier. The powder was formed by secondary aggregation, which reinforced the wettability of its surfaces. Such spherical clusters ensure that the powders created for ceramic slurry are compact and have good fluidity features microscopically. The optimal formula of the organic carrier system contained three components: 90 wt% organic solvent, 5 wt% ethyl cellulose and 5 wt% Span85. Meanwhile, an organic solvent was made with terpineol, butyldiglycol, 2-(2-butoxyethoxy) ethyl acetate at a ratio of 70:10:20. Mn–Co–Ni–O free-standing ultrathin sheets were prepared by a screen printing method using this slurry, which had a resistivity of 278.25 Ω cm at 25 °C, thermal constant of 3404.3 K, activation energy of 0.29 eV, and temperature coefficient of resistance of −3.83%/K. Furthermore, the response time of a small thermal sensor based on this sheet reached 32 ms. Such Mn–Co–Ni–O free-standing ultrathin sheets with excellent negative temperature coefficient characteristics are promising candidates for fast response temperature measurement.

Prognostic Significance of Lymphocyte Infiltrate Localization in Triple-Negative Breast Cancer.

High infiltration by tumor-infiltrating lymphocytes (TILs) is associated with favorable prognosis in different tumor types, but the clinical significance of their spatial localization within the tumor microenvironment is debated. To address this issue, we evaluated the accumulation of intratumoral TILs (itTILs) and stromal TILs (sTILs) in samples from 97 patients with early triple-negative breast cancer (TNBC) in the center (sTIL central) and periphery (sTIL peripheral) of tumor tissues. Moreover, the presence of primary and secondary lymphoid aggregates (LAs) and the expression levels of the cancer testis antigen (CTA), NY-ESO-1, and PD-L1 were explored. High infiltration by itTILs was observed in 12/97 samples (12.3%), unrelated to age, Ki67 expression, tumor size, histologic type and grade, and LA presence. NY-ESO-1 was expressed in tumor cells in 37 samples (38%), with a trend suggesting a correlation with itTIL infiltration (p = 0.0531). PD-L1 expression was detected in immune cells in 47 samples (49%) and was correlated with histologic grade, sTILs, and LA formation. The presence of primary LAs was significantly correlated with better disease-free survival (DFS) (p = 0.027). Moreover, no tumor progression was observed during >40 months of clinical follow up in the 12 patients with high itTILs or in the 14 patients with secondary LAs. Thus, careful evaluation of lymphoid infiltrate intratumoral localization might provide important prognostic information.

Changes in the Secondary Structure and Assembly of Proteins on Fluoride Ceramic (CeF3) Nanoparticle Surfaces.

Fluoride nanoparticles (NPs) are materials utilized in the biomedical field for applications including imaging of the brain. Their interactions with biological systems and molecules are being investigated, but the mechanism underlying these interactions remains unclear. We focused on possible changes in the secondary structure and aggregation state of proteins on the surface of NPs and investigated the principle underlying the changes using the amyloid β peptide (Aβ16–20) based on infrared spectrometry. CeF3 NPs (diameter 80 nm) were synthesized via thermal decomposition. Infrared spectrometry showed that the presence of CeF3 NPs promotes the formation of the β-sheet structure of Aβ16–20. This phenomenon was attributed to the hydrophobic interaction between NPs and Aβ peptides in aqueous environments, which causes the Aβ peptides to approach each other on the NP surface and form ordered hydrogen bonds. Because of the coexisting salts on the secondary structure and assembly of Aβ peptides, the formation of the β-sheet structure of Aβ peptides on the NP surface was suppressed in the presence of NH4+ and NO3– ions, suggesting the possibility that Aβ peptides were adsorbed and bound to the NP surface. The formation of the β-sheet structure of Aβ peptides was promoted in the presence of NH4+, whereas it was suppressed in the presence of NO3– because of the electrostatic interaction between the lysine residue of the Aβ peptide and the ions. Our findings will contribute to comparative studies on the effect of different NPs with different physicochemical properties on the molecular state of proteins.

A facile synthesis of raspberry-shaped Fe3O4 nanoaggregate and its magnetic and lithium-ion storage properties

Raspberry-shaped aggregates of Fe3O4 nanoparticles are synthesized via a facile hydrazine reduction method with high purity and good yield. The size of the Fe3O4 nanoparticles is in the range of 20–50 nm, which joins together to form raspberry-shaped secondary aggregates. In the absence of hydrazine, only Fe2O3 nanoparticles are formed. The Fe3O4 shows superparamagnetic behavior along with the coercivity and saturation magnetization value of 480 Oe and 41 emu/g at 5 K. The Fe3O4 aggregates show good lithium-ion storage capability with a combination of multi-walled carbon nanotubes. The electrode maintains a high reversible capacity of 662 mAhg−1 after 100 cycles at 50 mAg−1. Therefore, this can be a promising material for magnetic and lithium-ion battery applications.

Simulation to estimate the correlation of porous structure properties of secondary batteries determined through machine learning

The negative and positive electrodes of lithium-ion batteries exhibit different structural characteristics. In this study, considering the characteristics of each electrode layer of a lithium-ion battery, the correlation equation of the effective ion conductivity was formulated using a machine learning model. In general, the tortuosity depends on the porous structure, and therefore, the morphology of the packed particles. The graphite particles that constitute the negative electrode have a flat shape, in terms of the aspect ratio. Therefore, the tortuosity of a structure likely depends on the aspect ratio. In contrast, because the positive electrode represents a secondary aggregate, the tortuosity depends on the particle morphology. In this scenario, the parameters representing the particle shape are unclear. Considering these aspects, the tortuosity for the negative electrode in terms of the particle aspect ratio was predicted through nonlinear regression based on a support vector machine. The tortuosity for the positive electrode was predicted using the cross-sectional image of the electrode, with the particle shape considered as a feature. This clarified the correlation between the tortuosity and other structural properties or images. The obtained findings can be applied in various fields pertaining to porous materials and facilitate the optimization of structural designs. • CNN predicts tortuosity from cross-sectional images of lithium-ion batteries. • SVR model predicts tortuosity from porosity and particle aspect ratio. • SVR prediction suggests correlation between tortuosity and particle aspect ratio. • We proposed a new tortuosity correlation equation with the effect of aspect ratio.

Geotechnical properties of oil-polluted soil: a review.

Soil polluted by oil and its derivatives is a critical environmental issue worldwide that jeopardizes ecological systems and causes geotechnical problems. This review paper focuses on the previous studies concerning the impacts of oil pollution on soil geotechnical properties. To this end, related academic literature on this topic was investigated and discussed. The findings of this study demonstrated that the addition of oil pollution in coarse-grained soils significantly reduces particle surface roughness. On the other hand, in fine-grained soils, it results in flocculation and secondary aggregation of clay particles, less aggregated and loose packing in the soil matrix, the formation of isometric pores, the formation of fissure-like pores, and an increase in mesoporosity. In general, it was found that the geotechnical properties of oil-polluted soils are mostly determined by the physicochemical and/or physical interactions between the soil and contaminant. Additionally, previous research has demonstrated that oil pollutants alter the geotechnical propertiesof cohesive and non-cohesive soils significantly, including the Atterberg limits, particle-size distribution, compaction behavior, unconfined compressive strength, friction angle, cohesion, hydraulic conductivity, and consolidation characteristics. However, no general pattern could be established for the majority of them. Besides, it was found that the degree of geotechnical property alteration of oil-polluted soil is strongly influenced by the soil type and features, as well as the quantity, type, and chemical composition of oil pollutants.

The Performance of Concrete Made with Secondary Products-Recycled Coarse Aggregates, Recycled Cement Mortar, and Fly Ash-Slag Mix.

The properties of cement concrete using waste materials—namely, recycled cement mortar, fly ash–slag, and recycled concrete aggregate—are presented. A treatment process for waste materials is proposed. Two research experiments were conducted. In the first, concretes were made with fly ash–slag mix (FAS) and recycled cement mortar (RCM) as additions. The most favorable content of the concrete additive in the form of RCM and FAS was determined experimentally, and their influence on the physical and mechanical properties of concrete was established. For this purpose, 10 test series were carried out according to the experimental plan. In the second study, concretes containing FAS–RCM and recycled concrete aggregate (RCA) as a 30% replacement of natural aggregate (NA) were prepared. The compressive strength, frost resistance, water absorption, volume density, thermal conductivity, and microstructure were researched. The test results show that the addition of FAS–RCM and RCA can produce composites with better physical and mechanical properties compared with concrete made only of natural raw materials and cement. The detailed results show that FAS–RCM can be a valuable substitute for cement and RCA as a replacement for natural aggregates. Compared with traditional cement concretes, concretes made of FAS, RCM, and RCA are characterized by a higher compressive strength: 7% higher in the case of 30% replacement of NA by RCA with the additional use of the innovative FAS–RCM additive as 30% of the cement mass.

Temperature protocols to guide selective self-assembly of competing structures

Multicomponent self-assembly mixtures offer the possibility of encoding multiple target structures with the same set of interacting components. Selective retrieval of one of the stored structures has been attempted by preparing an initial state that favors the assembly of the required target, through seeding, concentration patterning, or specific choices of interaction strengths. This may not be possible in an experiment where on-the-fly reconfiguration of the building blocks to switch functionality may be required. In this paper, we explore principles of inverse design of a multicomponent, self-assembly mixture capable of encoding two competing structures that can be selected through simple temperature protocols. We design the target structures to realize the generic situation in which one of the targets has the lower nucleation barrier, while the other is globally more stable. We observe that, to avoid the formation of spurious or chimeric aggregates, the number of neighboring component pairs that occur in both structures should be minimal. Our design also requires the inclusion of components that are part of only one of the target structures. We observe, however, that to maximize the selectivity of retrieval, the component library itself should be maximally shared by the two targets, within such a constraint. We demonstrate that temperature protocols can be designed that lead to the formation of either one of the target structures with high selectivity. We discuss the important role played by secondary aggregation products in improving selectivity, which we term "vestigial aggregates."

Effect of Temperature and Humidity on the Synthesis of Alkali-Activated Binders Based on Bottom Ash from Municipal Waste Incineration

Weathered bottom ash (WBA) from municipal solid waste incineration is a calcium aluminosilicate-rich material mainly used in construction and civil engineering as a secondary aggregate. However, its use is also being considered as a precursor in the manufacture of alkali-activated binders (AA-WBA). This preliminary research aimed to deepen understanding of the potential use of WBA (&gt;8 mm fraction) as the sole precursor of alkali-activated binders. To gain better knowledge of this material, the physicochemical, mechanical, and environmental properties of AA-WBA binders were evaluated. In addition, the effect of curing temperature (25 °C, 45 °C, 65 °C, and 85 °C) and humidity conditions (oven and climate chamber) were assessed. The results of this study revealed that temperature and humidity conditions play a fundamental role during the early formation stages of AA-WBA binders. Maximum compactness and compressive strength (29.8 MPa) were obtained in the sample cured at 65 °C in the oven and room humidity. At higher temperatures (85 °C), a substantial decrease in mechanical strength (21.2 MPa) was observed due to a lower cohesion of the binder phases. Curing in the climate chamber led to an increase in humidity, and therefore a decrease in compressive strength. Finally, lower porosity and longer curing time substantially decreased the heavy metals and metalloid leaching concentration of AA-WBA binders.

Secondary polymer-induced particle aggregation and its rheological, electrical, and mechanical effects on PLA-based ternary composites

In order to fabricate electrically and mechanically reinforced biopolymer-based composites, we control the dispersion of the particles through the addition of a secondary polymer with high affinity to carbon black (CB) particles. The addition of a small amount of the secondary polymer induces the aggregation of CB particles beyond interfacial localization in a ternary composite. The aggregation and percolation network in poly(lactic acid) (PLA)-based ternary systems are investigated through a scaling analysis. According to rheological and geometric fractal analyses, the secondary polymer induces an aggregation of CB particles to form a percolation network because the induced-diffusion effect is stronger than the interaction between the particles, leading to a particle aggregate with a high-order structure. The modulus (G0′) of the CB/PLA binary composite has a scaling relationship with the particle volume fraction (φ), G0′∼φ1.92 (φc,G′=2.2%). In the CB/PLA binary composite, the addition of a small amount of secondary polymer having strong chemical affinity to CB changes the scaling relationship significantly depending on the type of the secondary polymer (G0′∼φ2.17∼2.53) with a lower percolation threshold (φc,G′) (φc,G′=0.96%). It also enhances the electrical percolation (electrical conductivity, σdc∼φ3.23∼3.78 φc,σ=1.50%−1.86% for ternary composites) with an increase in the exponent and a lower percolation threshold (φc,σ). The secondary polymer serves as a binder and causes the aggregates to be well dispersed, leading to a brittle-ductile transition and significant enhancement of the ductility.