In construction engineering and mining engineering, CaCl2 is the most commonly used calcium source in microbial-induced carbonate precipitation (MICP) technology because it can generate CaCO3, which ...has a high degree of crystallization and is thermodynamically stable, in tailings or soil. However, this calcium source is not the best choice for biocement. This study aims to compare the stability, strength, NH3 emission, and other effects of CaCl2, Ca(CH3COO)2, and Ca(NO3)2 in bio-cement to determine the best calcium source for bio-cement. The results indicate that after curing for 28 days, the strength of bio-cement with Ca(CH3COO)2 as its calcium source is higher than that with CaCl2 and Ca(NO3)2 as calcium sources. After adding cement to three calcium sources (CaCl2, Ca(CH3COO)2, and Ca(NO3)2), the CH3COO− sample is more stable and has higher biomass and urease activity than the Cl− and NO3− samples. Since CH3COO− is a weak acid, CH3COOH generated by CH3COO− can easily react with NH3 under the alkaline condition provided by cement, reducing NH3 emissions. When Ca(CH3COO)2 was used as a calcium source, the NH3 emission of its sample decreased by 54.2% and 51.4% compared with CaCl2 and Ca(NO3)2. Therefore, CH3COO−, as an anionic calcium source, will have more application prospects than CaCl2 and Ca(NO3) in bio-cement production.
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•Ca(CH3COO)2 used as the calcium source is more suitable than others for biocement.•Part of CH3COO− reacts with NH3 to generate CH3COONH4, reducing NH3 emissions.•CH3COO− improves the mineralization rate of MICP because of its large relative molar mass.•Ca(CH3COO)2 helps to generate more CaCO3 to improve the compactness of biocement.•The stability of Ca(CH3COO)2 in biocement is higher than that of CaCl2 and Ca(NO3)2.
High-volume fly ash (FA) cement presented a slow setting and lower early compressive strength, restricting the utilization in cemented paste backfill (CPB). The present work investigated the ...feasibility of using metakaolin with various particle sizes and content to modify the properties of FA cement. Reaction kinetics, rheological properties, setting time, compressive strength, hydration products, and the CPB samples' microstructure were thoroughly studied. The results showed that 5 wt% of super-fine metakaolin (SMK) could strongly promote the binder hydration, leading to the formation of a more compact matrix with higher early compressive strength. The 3 d-compressive strength of the CPB samples was increased by around 216% after replaced by 5 wt% of SMK. Besides, the binder doped with 5 wt% SMK showed better environmental and cost performance.
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•Adding 5 wt% of SMK increased the 3 d- strength of the CPB samples by 216%.•SMK promoted the hydration and refined the pore structure of CPB.•The addition of MK decreased the flowability of the fresh CPB.•The presence of MK favored the formation of more AFm phases.
Gonad development is a highly regulated process that coordinates cell specification and morphogenesis to produce sex‐specific organ structures that are required for fertility, such as testicular ...seminiferous tubules and ovarian follicles. While sex determination occurs within specialized gonadal supporting cells, sexual differentiation is evident throughout the entire organ, including within the interstitial compartment, which contains immune cells and vasculature. While immune and vascular cells have been traditionally appreciated for their supporting roles during tissue growth and homeostasis, an increasing body of evidence supports the idea that these cell types are critical drivers of sexually dimorphic morphogenesis of the gonad. Myeloid immune cells, such as macrophages, are essential for multiple aspects of gonadogenesis and fertility, including for forming and maintaining gonadal vasculature in both sexes at varying stages of life. While vasculature is long known for supporting organ growth and serving as an export mechanism for gonadal sex steroids in utero, it is also an important component of fetal testicular morphogenesis and differentiation; additionally, it is vital for ovarian corpus luteal function and maintenance of pregnancy. These findings point toward a new paradigm in which immune cells and blood vessels are integral components of sexual differentiation and organogenesis. In this review, we discuss the state of the field regarding the diverse roles of immune and vascular cells during organogenesis of the testis and ovary and highlight outstanding questions in the field that could stimulate new research into these previously underappreciated constituents of the gonad.
Vasculature and immune cells are traditionally known for their supportive roles in tissue growth and immunity. However, increasing evidence suggests that these cell types are critical, active drivers of organogenesis, in particular within the reproductive system. Here we review the diverse roles of vasculature and immune cells in morphogenesis, differentiation, and function of the testis and ovary. These findings could provide new insights into our understanding of development and disease.
To improve the properties of cemented ultra-fine tailings backfill (CUTB), the authors intend to outline the framework of the effect of steel slag (SS) on the properties of CUTB. Therefore, ...flowability, unconfined compressive strength (UCS), hydration products, and pore structure were used to investigate the properties of CUTB samples. The results showed that the incorporation of SS increased the flow spread by increasing the water film thickness (WFT). Unconfined compressive strength (UCS) was observed to be enhanced when the content of SS did not exceed 20 wt%. Hydration phase evolution tested by X-ray diffraction, thermogravimetry, and thermodynamic modeling indicated the additional formation of hydrotalcite-like phases (Ht). This contributed to a denser microstructure. Besides, lower total porosity and critical pore diameter (dcr) obtained by mercury intrusion porosimeter tests were observed in samples with SS addition, which could favor the strength development. On the other hand, toxicity characteristic leaching procedure (TCLP) results indicated that the CUTB exhibited good environmental performance.
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•Adding SS increased the flowability of UCTB slurry through enhancing the WFT value.•The addition of SS increased the UCS of UCTB samples after curing for 28 days.•Incorporating SS reduced the C-S-H formation but increased the Ht generation.•Refined pore structure due to the addition of SS was observed.
A Generalized Methodology for Data Analysis Angelov, Plamen P.; Gu, Xiaowei; Principe, Jose C.
IEEE transactions on cybernetics,
10/2018, Letnik:
48, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Based on a critical analysis of data analytics and its foundations, we propose a functional approach to estimate data ensemble properties, which is based entirely on the empirical observations of ...discrete data samples and the relative proximity of these points in the data space and hence named empirical data analysis (EDA). The ensemble functions include the nonparametric square centrality (a measure of closeness used in graph theory) and typicality (an empirically derived quantity which resembles probability). A distinctive feature of the proposed new functional approach to data analysis is that it does not assume randomness or determinism of the empirically observed data, nor independence. The typicality is derived from the discrete data directly in contrast to the traditional approach, where a continuous probability density function is assumed a priori . The typicality is expressed in a closed analytical form that can be calculated recursively and, thus, is computationally very efficient. The proposed nonparametric estimators of the ensemble properties of the data can also be interpreted as a discrete form of the information potential (known from the information theoretic learning theory as well as the Parzen windows). Therefore, EDA is very suitable for the current move to a data-rich environment, where the understanding of the underlying phenomena behind the available vast amounts of data is often not clear. We also present an extension of EDA for inference. The areas of applications of the new methodology of the EDA are wide because it concerns the very foundation of data analysis. Preliminary tests show its good performance in comparison to traditional techniques.
A growing body of evidence demonstrates that fetal-derived tissue-resident macrophages have developmental functions. It has been proposed that macrophages promote testicular functions, but which ...macrophage populations are involved is unclear. Previous studies showed that macrophages play critical roles in fetal testis morphogenesis and described two adult testicular macrophage populations, interstitial and peritubular. There has been debate regarding the hematopoietic origins of testicular macrophages and whether distinct macrophage populations promote specific testicular functions. Here our hematopoietic lineage-tracing studies in mice show that yolk-sac-derived macrophages comprise the earliest testicular macrophages, while fetal hematopoietic stem cells (HSCs) generate monocytes that colonize the gonad during a narrow time window in a Sertoli-cell-dependent manner and differentiate into adult testicular macrophages. Finally, we show that yolk-sac-derived versus HSC-derived macrophages have distinct functions during testis morphogenesis, while interstitial macrophages specifically promote adult Leydig cell steroidogenesis. Our findings provide insight into testicular macrophage origins and their tissue-specific roles.
In view of the problem of soil erosion control and ecological restoration of the tailings reservoir slope, the characteristics of runoff, sediment yield, and velocity of sheet flow of the tailings ...reservoir slope under four conditions (goosegrass, vetiver, clover, and bare slope) were studied by conducting a laboratory test of hydraulic erosion. Based on the direct shear test and triaxial shear test of the root–soil composites, the optimum range of root–soil composites was determined, and the stress–strain relationship, strength characteristics, and failure form of root–soil composites under different confining pressure were studied. The results show that as a whole, the characteristics of runoff, sediment yield, and velocity of sheet flow in the tailings slope under the condition of vetiver are more advantageous than other vegetation to the reinforcement of the slope. The shear strength of the root–soil composites increases with the increase of the root content, and the shear strength of the root–soil composites remains unchanged or decreased when it reaches a certain range; the interval of the root content 0.3–0.4% is the best root content of the root–soil composites. This study’s results can provide an important theoretical basis and reference value for comprehensive control of a tailings reservoir slope and restoration of ecological stability.
This study proposes to construct a model using random forest method, an efficient machine learning‐based method, to predict the spatial structure and temporal evolution of the sea surface temperature ...(SST) cooling induced by northwest Pacific tropical cyclones (TCs), a process of the so‐called wind pump. The predictors in use include 12 predictors related to TC characteristics and pre‐storm ocean conditions. The model is shown to skillfully predict the spatiotemporal evolutions of the cold wake generated by TCs of different intensity groups, and capture the cross‐case variance in the observed SST response. Another model is further built based on the same method to assess the relative importance of the 12 predictors in determining the magnitude of the maximum cooling. Computations of feature scores of those predictors show that TC intensity, translation speed and size, and pre‐storm mixed layer depth and SST dominate, depending on the area where the cooling is considered.
Plain Language Summary
While many studies have been devoted to understanding the processes and mechanisms underlying the sea surface temperature (SST) cooling induced by tropical cyclones (TCs), few studies have attempted to predict the spatial and temporal evolution of the sea surface temperature (SST) cooling triggered by TCs. In this study, we proposed to achieve this goal by building a model using an efficient and robust machine learning‐based method. The constructed model uses 12 predictors associated with TC characteristics (e.g., intensity, and translation speed) and pre‐storm ocean states (e.g., mixed layer depth). The model performs well in producing the TC‐induced spatial structure and temporal evolution of the cold wake and can capture most of the variance in the observed SST response. We quantified the relative importance of the 12 predictors, and found that TC intensity, translation speed and size, and pre‐storm mixed layer depth and SST dominate in deciding the magnitude of the SST response. The results and proposed method have important implications for predicting the response of ocean primary production to the TC wind pump effects.
Key Points
A machine learning‐based model is built to predict the spatiotemporal evolution of the tropical cyclone‐induced sea surface temperature response
The model well predicts the spatial structure and temporal evolution of the observed response and captures the observed cross‐case variance
Feature scores are computed to assess the relative importance of the predictors in determining the magnitude of the SST response
In order to tackle high dimensional, complex problems, learning models have to go deeper. In this article, a novel multilayer ensemble learning model with first-order evolving fuzzy systems as its ...building blocks is introduced. The proposed approach can effectively learn from streaming data on a sample-by-sample basis and self-organizes its multilayered system structure and meta-parameters in a feedforward, noniterative manner. Benefiting from its multilayered distributed representation learning ability, the ensemble system not only demonstrates the state-of-the-art performance on various problems, but also offers high level of system transparency and explainability. Theoretical justifications and experimental investigation show the validity and effectiveness of the proposed concept and general principles.
This paper introduces a novel self-training hierarchical prototype-based approach for semi-supervised classification. The proposed approach firstly identifies meaningful prototypes from labelled ...samples at multiple levels of granularity and, then, self-organizes a highly transparent, multi-layered recognition model by arranging them in a form of pyramidal hierarchies. After this, the learning model continues to self-evolve its structure and self-expand its knowledge base to incorporate new patterns recognized from unlabelled samples by exploiting the pseudo-label technique. Thanks to its prototype-based nature, the overall computational process of the proposed approach is highly explainable and traceable. Experimental studies with various benchmark image recognition problems demonstrate the state-of-the-art performance of the proposed approach, showing its strong capability to mine key information from unlabelled data for classification.
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