Complex Admixtures Research Articles

INFLUENCE OF PLASTICIZING AND AIR-ENTRAINING ADMIXTURES ON CONCRETE PROPERTIES

In the modern construction industry of Kazakhstan, to ensure the needs of the market, there is an urgent essential to improve the quality of concrete and expand its functional purpose. To a large extent, this is achieved by designing concrete as composite materials with different structures, quantities and nature of components. The multicomponent composition makes it possible to effectively manage the structure formation processes of the concrete cementing matrix and obtain concretes with the required properties. This article presented the effect of plasticizing and air-entraining admixtures on the properties of heavy concrete. The compositions of concrete mixture with plasticizing and air-entraining admixtures were selected. The results of study of plasticizing and air-entraining admixtures effect on average density, workability, compressive strength of concrete samples are presented. The effectiveness of introduction of a complex admixtures was evaluated in order to further improve operational properties of concrete. The plasticizing effect makes it possible to increase workability of concrete mortar while by reducing water-cement ratio from 0,5 to 0,38. Due to this, density and strength of concrete increased while improving operational characteristics. The combined effect of plasticizing and air-entraining admixtures had a positive effect on mobility of concrete mortar and its strength of concrete samples. The significant strength of 47,2 MPa was achieved with the combined introduction of a plasticizing and air-entraining admixtures in the amount of 1,2% and 0,5% of the cement weight, thereby increasing the strength of concrete samples by 32% compared to the control sample.

Deep learning approaches for prediction of adiabatic temperature rise of concrete with complex mixture constituents

Temperature control and crack prevention of mass concrete are significant to the safety and durability of structures such as dams and long-span bridges. Adiabatic temperature rise is the key issue in thermal and crack risk analysis of mass concrete. Due to the substantial diversity of admixtures influencing the hydration process in modern concrete, it is challenging to develop a comprehensive analytical model to predict adiabatic temperature rise based on theoretical frameworks. As a data-driven approach, deep learning (DL) provides a potential solution for predicting the properties of complex materials in recent years. DL model based on artificial neuron network (ANN) and recurrent neuron network (RNN) were employed in this study to predict adiabatic temperature rise considering 15 variables as input parameters. The determination coefficient (R2) of the prediction results given from ANN and RNN was 0.7616 and 0.8542, respectively. Segmentation technique and bidirectional deep (BD) neuron network algorithm were implemented to improve the performance of RNN. It was demonstrated that BD-RNN provided better results with promising statistical parameters (R2 = 0.9245) and curve fitting of adiabatic temperature rise profiles. Through optimization and k-fold cross-validation, an evolutionary DL model was developed for reliable prediction of adiabatic temperature rise of concrete with complex admixtures.

A Complex Organomineral Admixture For Cement Saving

The aim of the research is to prepare a composition of a complex organomineral admixture based on industrial waste for cement saving, to experimentally establish the optimum crushing degree of an ash-and-slag waste composition and to estimate the ratio between mineral and organic components of the complex admixture, ensuring the possibility of reducing cement consumption without loss of concrete strength. As a mineral component of the complex admixture the wastes from thermoelectric power stations were used, representing by an ash-and-slag waste composition crushed to a fine powder condition. Optimization of the complex admixture is carried out using mathematical methods of the theory of planning experiments.
 As a result of this research a quadratic polynomial model of influence of crushing fineness of ash-and-slag wastes and cement consumption on concrete strength has been obtained. It is established, that depending on the degree of crushing of ash-and-slag waste composition within values of specific surface of received powder from 2400 to 4000 cm2/g it is possible to reduce cement consumption by 8-18 % without loss in strength of concrete. The introduction of complex organomineral admixtures into concrete is very effective as it saves cement. However, special studies are required in each case. The compositions of the new complex admixtures are tested on the basis of traditional raw materials, and economic efficiency in saving cement is established. It is proposed to use the methodology of mathematical modelling of the technological complex system under study, presented in this article.

Abstract 4: Temporal and spatial topography of cell proliferation in cancer

Abstract Uncontrolled cell proliferation is a defining feature of malignancy. Current understanding of proliferation, particularly in humans, derives primarily from studying cells growing rapidly in the non-physiological conditions of cell culture. However, tumors are exceedingly complex admixtures of different cell types and subclonal malignant populations comprising proliferative, non-proliferative, and arrested states that are influenced by physical, metabolic, and molecular conditions. Images of single or small sets of protein markers from fixed tissue samples only provide limited and static views into the nature of these complex states. Here we identify proliferation states and develop a quantitative framework to extract cell cycle dynamics from multiplexed, spatially-resolved tissue images of millions of tumor cells from human cancers and genetically engineered tumors in mice. Across spatial scales, tumors display intrinsic regional variability in proliferation patterns and in the coherence of cell cycle markers in high-dimensional space. Cell cycle dynamics and cell cycle coherence are not solely a function of tumor growth and oncogene expression and rapidly adapt following genetic and therapeutic perturbations. Replacing binary metrics with multivariate traits provides a quantitative framework for extracting multidimensional dynamic information from static images that is broadly applicable to the study of temporal processes within the native architecture of human disease tissues. Citation Format: Giorgio Gaglia, Sheheryar Kabraji, Danae Argyropoulou, Yang Dai, Johann Bergholz, Shannon Coy, Jia-Ren Lin, Eric P. Winer, Deborah Dillon, Jean J. Zhao, Peter K. Sorger, Sandro Santagata. Temporal and spatial topography of cell proliferation in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 4.

Improvement of functional performance of concrete in livestock buildings through the use of complex admixtures

When examining concrete in livestock buildings, signs of corrosion and destruction of concrete floors and walls were found. Experimental studies have identified main critical points that directly affected concrete continuity. Excessive moisture, use of corrosive acidic or alkaline disinfectants and presence of natural excretions of animals (urine and feces) were found in livestock buildings. To solve this problem, admixtures were proposed: yellow iron oxide pigment and liquid glass which improve strength characteristics of concrete, its heat resistance and reduce penetrability. It was proved by the conducted studies that introduction into concrete of admixtures in quantities from 0.5 % to 2 % has resulted in a 2.8 times smaller depth of chloride penetration as compared to the control specimens. This was due to a decrease in water absorption by concrete when introducing iron oxide, cuprous sulphate, peracetic acid and sodium silicate which reduced pore size in samples. It was proposed as an innovation to assess thermal stability of concrete using the method of temperature-programmed desorption mass spectrometry (TPMS) based on the dependence of evolution of carbon monoxide and carbon dioxide from samples of carbonate-containing substances on the sample temperature. Microbiological studies have identified microbes of Penicillium and Fusarium species, bacteria Escherichia coli and Pseudomonas aeruginosa, which cause corrosion of concrete in livestock buildings. Numerous experiments have shown that the proposed admixtures added to the concrete (based on yellow iron oxide pigment (1.5‒2.0 wt. %), peracetic acid (0.2‒0.3 wt. %), liquid glass (2‒3 wt. %) and cuprous sulfate (0.5‒1.0 wt. %) had antimicrobial properties and thus prospects for their use in animal husbandry

Transmigrant media: Mediating place, mobility, and subjectivity

This article contributes to the exploration of interrelationships between human and media mobilities through analysis of qualitative interviews with 18 Southeast Asian transmigrants in Australia. This group demonstrated three main orientations toward the media they habitually engaged. In the memorial-affective orientation, respondents re-engaged media familiar from remembered pre-migration childhood and family contexts. An ambivalent-localizing orientation was taken toward Australian legacy media, some of which respondents found helped them relate to Australian culture while other forms were experienced as xenophobic and alienating. In the cosmopolitan-global orientation, respondents engaged global corporate, largely Anglophone media in ways that reinforced their sense of themselves as mobile and cosmopolitan. Most importantly, in our respondents’ experience, these three orientations were often not separable but interwoven into complex admixtures. We explore the implications of this hybrid experience of location through media both for the conceptualization of place in globalization, and for the study of migrant media.

MultiWaver 2.0: modeling discrete and continuous gene flow to reconstruct complex population admixtures.

Our goal in developing the MultiWaver software series was to be able to infer population admixture history under various complex scenarios. The earlier version of MultiWaver considered only discrete admixture models. Here, we report a newly developed version, MultiWaver 2.0, that implements a more flexible framework and is capable of inferring multiple-wave admixture histories under both discrete and continuous admixture models. MultiWaver 2.0 can automatically select an optimal admixture model based on the length distribution of ancestral tracks of chromosomes, and the program can estimate the corresponding parameters under the selected model. Specifically, for discrete admixture models, we used a likelihood ratio test (LRT) to determine the optimal discrete model and an expectation-maximization algorithm to estimate the parameters. In addition, according to the principles of the Bayesian Information Criterion (BIC), we compared the optimal discrete model with several continuous admixture models. In MultiWaver 2.0, we also applied a bootstrapping technique to provide levels of support for the chosen model and the confidence interval (CI) of the estimations of admixture time. Simulation studies validated the reliability and effectiveness of our method. Finally, the program performed well when applied to real datasets of typical admixed populations, such as African Americans, Uyghurs, and Hazaras.

The research of clinker monominerals modified suspensions’ rheological properties

The findings of studying the influence of the superplasticizers of various natures on rheological properties of clinker monominerals’ water suspensions have been presented. It has been shown that the plasticizing activity of admixtures is determined by the nature and the specific surface of a monomineral and the nature of the admixture’s hydrophilic groups, and for complex admixtures also with the ratio of individual components. The optimal admixture dosages for monomineral suspensions of clinker minerals change in the row C2S, C3S, C3A, C4AF, which allows forecasting the influence of admixtures on rheological properties of systems with cements of various mineral compositions. The obtained data correlate with the research findings of the admixtures’ influence on cements of various mineral composition, which allows deducing the influence of admixtures on the systems with other cements, and providing the economically and technologically feasible selection and consumption of admixtures depending on the type of cement and its mineral composition.

(Oxo)(Fluoro)-Aluminates in KF-Al2O3 System: Thermal Stability and Structural Correlation.

Precise investigation of part of the phase diagram of KF-Al2O3 system was performed in an experiment combining different techniques. Solidified mixtures of KF-Al2O3 were studied by X-ray powder diffraction and high-field solid-state NMR spectroscopy over a wide range of compositions. To help with the interpretation of the NMR spectra of the solidified samples found as complex admixtures, we synthesized the following pure compounds: KAlO2, K2Al22O34, α-K3AlF6, KAlF4, and K2Al2O3F2. These compounds were then characterized using various solid-state NMR techniques, including MQ-MAS and D-HMQC. NMR parameters of the pure compounds were finally determined using first-principles density functional theory calculations. The phase diagram of KF-Al2O3 with the alumina content up to 30 mol % was determined by means of thermal analysis. Thermal analysis was also used for the description of the thermal stability of one synthesized compound, K2Al2O3F2.

Inference of multiple-wave population admixture by modeling decay of linkage disequilibrium with polynomial functions.

To infer the histories of population admixture, one important challenge with methods based on the admixture linkage disequilibrium (ALD) is to remove the effect of source LD (SLD), which is directly inherited from source populations. In previous methods, only the decay curve of weighted LD between pairs of sites whose genetic distance were larger than a certain starting distance was fitted by single or multiple exponential functions, for the inference of recent single- or multiple-wave admixture. However, the effect of SLD has not been well defined and no tool has been developed to estimate the effect of SLD on weighted LD decay. In this study, we defined the SLD in the formularized weighted LD statistic under the two-way admixture model and proposed a polynomial spectrum (p-spectrum) to study the weighted SLD and weighted LD. We also found that reference populations could be used to reduce the SLD in weighted LD statistics. We further developed a method, iMAAPs, to infer multiple-wave admixture by fitting ALD using a p-spectrum. We evaluated the performance of iMAAPs under various admixture models in simulated data and applied iMAAPs to the analysis of genome-wide single nucleotide polymorphism data from the Human Genome Diversity Project and the HapMap Project. We showed that iMAAPs is a considerable improvement over other current methods and further facilitates the inference of histories of complex population admixtures.

Superconducting phase diagram of itinerant antiferromagnets

We study the phase diagram of the Hubbard model in the weak-coupling limit for coexisting spin-density-wave order and spin-fluctuation-mediated superconductivity. Both longitudinal and transverse spin fluctuations contribute significantly to the effective interaction potential, which creates Cooper pairs of the quasi-particles of the antiferromagnetic metallic state. We find a dominant $d_{x^2-y^2}$-wave solution in both electron- and hole-doped cases. In the quasi-spin triplet channel, the longitudinal fluctuations give rise to an effective attraction supporting a $p$-wave gap, but are overcome by repulsive contributions from the transverse fluctuations which disfavor $p$-wave pairing compared to $d_{x^2-y^2}$. The sub-leading pair instability is found to be in the $g$-wave channel, but complex admixtures of $d$ and $g$ are not energetically favored since their nodal structures coincide. Inclusion of interband pairing, in which each fermion in the Cooper pair belongs to a different spin-density-wave band, is considered for a range of electron dopings in the regime of well-developed magnetic order. We demonstrate that these interband pairing gaps, which are non-zero in the magnetic state, must have the same parity under inversion as the normal intraband gaps. The self-consistent solution to the full system of five coupled gap equations give intraband and interband pairing gaps of $d_{x^2-y^2}$ structure and similar gap magnitude. In conclusion, the $d_{x^2-y^2}$ gap dominates for both hole and electron doping inside the spin-density-wave phase.

Concrete with organic mineral admixture based on fine grinding cooper slag

The problem of applying copper manufacturing wastes locating in Chelyabinsk region as a component of organic mineral admixture for concrete with industrial wastes production is considered in this article. Also, organic mineral admixture consisting of superplasticizers, based on esters with carboxyl groups, has not yet been sufficiently studied due to the diversity of species and the complexity of chemical structure. This trend is current for today’s science because of the growing rates and scales of building production, in particular, concrete works. Using new complex admixtures processed of industrial by-products showed their effectiveness. Copper slag dumps located in Urals federal district haven’t been widely used in building production or in other industrial production up to the present time. Efficient utilization of copper production waste materials will help to solve the ecological problems in most regions of Russia. The structure formation period of cement stone with organic mineral admixture, based on fine grinding cooper slag and superplasticizer, is also studied in the article. The thermal variation diagram of concrete mixture with organic mineral admixture during 22 hours of hardening under normal condition are shown and the results of ultrasound of concrete forming structure period during 6 hours of hardening are presented in this article. The strength development process diagram of concrete with organic mineral admixture during 28 days of hardening under normal condition and the research results of the compressive strength of concrete samples are also presented. The obtained characteristics confirm the prospects of applying this kind of non-ferrous metallurgy wastes in the concrete. Also, the obtained results allow us to conclude the significant advantages of using this kind of complex admixture for concrete production with different purpose and in different fields of application.

Possible Incompatibility between Amino Acids and Copper in Solutions for Pediatric Parenteral Nutrition.

The nutrient formulas used for parenteral nutrition are highly complex admixtures of multiple solutions, infused by the IV route to patients who are unable to receive nutrition by mouth or by the enteral route. The administered products contain macronutrients (amino acids, dextrose, and lipids), electrolytes (sodium, potassium, calcium, phosphate, magnesium, chloride, and acetate), micronutrients (vitamins, trace elements), and water. The solution for parenteral administration can be prepared as a “2-in-1” solution, with lipids being infused separately from the other components, or as a “3-in-1” admixture, in which all components are mixed together. 1 The complexity of these solutions poses a significant risk of incompatibility between components. The most widely known incompatibility involving components of parenteral nutrition solutions is precipitation of calcium phosphate. In 1994, the US Food and Drug Administration published a safe ty communication describing cases of incompatibility between calcium and phosphate in parenteral nutrition solutions, in which infusion of the solutions resulted in death (2 patients) or respiratory distress (2 patients). 2 Measures taken to prevent adverse events related to incompatibilities include the use of filters during infusion, specifically 0.22-µm filters for 2-in-1 solutions and 1.2-µm filters for 3-in-1 admixtures. For compounded parenteral nutrition solutions, components should be added in the same order every time, and contact between incompatible solutions should be minimized. 3 Specif ically, phosphates should be added at the beginning of the mixing sequence, and calcium gluconate should be added last, such that the calcium is added when the volume of the solution being compounded is at its maximum. 1

The usage of ultra-fine cement as an admixture to increase the compressive strength of Portland cement mortars

The High-Strength Cement (HSC) technology is based on modification of Normal Use Portland Cement (NUPC) by complex admixtures, optimization of mixture design and grinding process. The present work shows the results of preparing and using Ultra-Fine Cement (UFC) as a binder material addition with no extra admixtures of different chemical composition to increase the compressive strength of mortars. The aim of this work is to demonstrate how a NUPC can be converted into a sort of HSC; it was observed that the 70–60wt%NUPC+30–40wt%UFC blend satisfies the goal of increasing mortar’s compressive strength.

Ancestry Inference in Complex Admixtures via Variable-length Markov Chain Linkage Models

Inferring the ancestral origin of chromosomal segments in admixed individuals is key for genetic applications, ranging from analyzing population demographics and history, to mapping disease genes. Previous methods addressed ancestry inference by using either weak models of linkage disequilibrium, or large models that make explicit use of ancestral haplotypes. In this paper we introduce ALLOY, an efficient method that incorporates generalized, but highly expressive, linkage disequilibrium models. ALLOY applies a factorial hidden Markov model to capture the parallel process producing the maternal and paternal admixed haplotypes, and models the background linkage disequilibrium in the ancestral populations via an inhomogeneous variable-length Markov chain. We test ALLOY in a broad range of scenarios ranging from recent to ancient admixtures with up to four ancestral populations. We show that ALLOY outperforms the previous state of the art, and is robust to uncertainties in model parameters.

Relationships between spatio‐temporal environmental and genetic variation reveal an important influence of exogenous selection in a pupfish hybrid zone

The importance of exogenous selection in a natural hybrid zone between the pupfishes Cyprinodon atrorus and Cyprinodon bifasciatus was tested via spatio-temporal analyses of environmental and genetic change over winter, spring and summer for three consecutive years. A critical influence of exogenous selection on hybrid zone regulation was demonstrated by a significant relationship between environmental (salinity and temperature) and genetic (three diagnostic nuDNA loci) variation over space and time (seasons) in the Rio Churince system, Cuatro Ciénegas, Mexico. At sites environmentally more similar to parental habitats, the genetic composition of hybrids was stable and similar to the resident parental species, whereas complex admixtures of parental and hybrid genotypic classes characterized intermediate environments, as did the greatest change in allelic and genotypic frequencies across seasons. Within hybrids across the entire Rio Churince system, seasonal changes in allelic and genotypic frequencies were consistent with results from previous reciprocal transplant experiments, which showed C.bifasciatus to suffer high mortality (75%) when exposed to the habitat of C.atrorus in winter (extreme temperature lows and variability) and summer (abrupt salinity change and extreme temperature highs and variability). Although unconfirmed, the distributional limits of C.atrorus and C.atrorus-like hybrids appear to be governed by similar constraints (predation or competition). The argument favouring evolutionary significance of hybridization in animals is bolstered by the results of this study, which links the importance of exogenous selection in a contemporary hybrid zone between C.atrorus and C.bifasciatus to previous demonstration of the long-term evolutionary significance of environmental variation and introgression on the phenotypic diversification Cuatro Ciénegas Cyprinodon.

Studies on Compatibility between Slipform Paving Cement Concrete and Complex Admixtures

The slipform paving technique has been utilized widely in the construction of high-class highway cement concrete pavements in China, resulting in increased use of complex admixtures. Complex admixtures usually contain various components that may have potential compatibility issues, not only between admixtures and cement, but also between admixture components. In order to alleviate or eliminate potential incompatibility problems, it is necessary to adjust the mix proportions and admixture chemical components by taking into account the real-life materials and surrounding conditions. An optimum dosage of the complex admixture should be determined according to the specific job requirements and construction technique. Compatibility issues always arise between admixtures and cements. It was found that Na2 S O4 and Ca Cl2 may increase the early strength, but also may reduce the slump of the mix. When the resin-based air-entraining agent and water reducers were used together, they produced a large amount of resid...

A reconnaissance laser Raman and Fourier transform infrared survey of silcretes from the Kalahari Desert, Botswana

AbstractThis paper documents the first application of laser Raman and Fourier transform infrared vibrational spectroscopic techniques (Raman/FT‐IR) to the analysis of silcrete. Analyses are undertaken at a reconnaissance level on bulk silcrete samples of varying ages, drawn from a range of geomorphological settings across the Kalahari Desert of Botswana. Results suggest that Raman/FT‐IR, combined with inspection of petrographic thin‐sections, provides an effective tool for establishing the range and type of silica polymorphs present within samples. Analyses of Raman and mid‐infrared spectra indicate that the majority of silcretes are dominated by α‐quartz with subordinate moganite. There is, however, considerable inter‐sample variability, ranging from silcretes consisting of almost pure quartz to those containing complex admixtures of disordered microcrystalline or non‐crystalline silica in association with quartz and clays. Taken as a whole, the results are supportive of a similar environment of formation for all samples, with development taking place under broadly semi‐arid conditions. Raman/FT‐IR is also shown to have a number of benefits over other conventional techniques for silcrete analysis, such as X‐ray diffraction. Firstly, inspection of the OH region of the infrared spectrum of bulk samples is shown to have potential for establishing the provenance of quartz clasts within silcrete host sediments, through the identification of high‐temperature conditions of crystal growth in detrital quartz grains. Raman and mid‐infrared analyses also permit clay identification within silcrete samples where such minerals are not readily resolvable in thin‐section. The technique further allows the relative maturity of silcrete cements to be established, particularly for recently formed silcretes. These are found typically to contain less mature silica polymorphs and incorporate larger quantities of molecular water than α‐quartz dominated silcretes. Comparisons of the range of silica polymorphs identified using Raman/FT‐IR with those established by petrographic investigation can also reveal evidence of silica paragenesis. This is the case in two stratigraphically older samples from the Kalahari margin in which less stable silica polymorphs appear to have transformed over time to chalcedony and microquartz. Whilst the ‘whole‐rock’ approach used in this survey generates some problems of interpretation, the overall results suggest that the use of micro‐Raman and micro‐FT‐IR techniques should allow even more precise information about the environments of formation and developmental histories of silcrete profiles to be produced in the future. Copyright © 2004 John Wiley & Sons, Ltd.

Effect of complex admixtures on cement properties and the development of a test procedure for the evaluation of high-strength cements

Recent research has shown that a state-of-the-art process for high-performance (HP) cement adds a new dimension to ‘classical’ cement technology. The key idea of the process involves the mechano-chemical activation of cement at the grinding stage. A silica-based complex admixture is used for the activation of the cement imparting high strength and improved durability to mortars and concrete. This paper describes the effect of different complex admixtures on the strength of HP cement. According to the available results, mortars based on HP cement possess a compressive strength of up to 148 MPa. A comparison of alternative evaluation methods helps to recommend the test procedure for HP and high-strength cement.

Effect of complex admixtures on cement properties and the development of a test procedure for the evaluation of high-strength cements

Recent research has shown that a state-of-the-art process for high-performance (HP) cement adds a new dimension to ‘classical’ cement technology. The key idea of the process involves the mechano-chemical activation of cement at the grinding stage. A silica-based complex admixture is used for the activation of the cement imparting high strength and improved durability to mortars and concrete. This paper describes the effect of different complex admixtures on the strength of HP cement. According to the available results, mortars based on HP cement possess a compressive strength of up to 148 MPa. A comparison of alternative evaluation methods helps to recommend the test procedure for HP and high-strength cement.