We characterize the long-term development of high-viscosity gas–liquid intermittent flows by means of a detrended fluctuation analysis (DFA). To this end, the pressures measured at different locations along an ad hoc experimental flow line are compared. We then analyze the relevant time-series to determine the evolution of the various kinds of intermittent flow patterns associated with the mixtures under consideration. Although no pattern transitions are observed in the presence of high-viscosity mixtures, we show that the dynamical attributes of each kind of intermittence evolves from one point to another within the transport system. The analysis indicates that the loss of a long-range correlation between the pressure responses are due to the discharge processes.

We study a high-viscosity two-phase flow through an analysis of the corresponding pressure signals. In particular, we investigate the flow of a glycerin–air mixture moving through a horizontal pipeline with a U-section installed midway along the pipe. Different combinations of liquid and air mass flow rates are experimentally tested. Then, we examine the moments of the statistical distributions obtained from the resulting pressure time series, in order to highlight the significant dynamical traits of the flow. Finally, we propose a novel correlation with two dimensionless parameters: the Euler number and a mass-flow-rate ratio to predict the pressure gradient in high-viscosity two-phase flow. Distinctive variations of the pressure gradients are observed in each section of the pipeline, which suggest that the local flow dynamics must not be disregarded in favor of global considerations.

Production of heavy crude oil in Mexico, and worldwide, is increasing which has led to the application of different methods to reduce viscosity or to enhance transport through stratified flow to continue using the existing infrastructures. In this context, injecting a viscosity improver that does not mix completely with the crude, establishes a liquid-liquid stratified flow. On the basis of a parallel plates model, comparing the increase of flow that occurs in the one-phase case which assumes a complete mixture between the crude and the viscosity improver against another stratified liquid-liquid (no mixing between the oil and compared improver); it was found that in both cases there is a flow increase for the same pressure drop with a maximum for the case in which the flow improver is between the plates and the crude.

Objectives: This study aims to evaluate the potential of lightweight concrete mixtures incorporating sustainable materials, such as nopal mucilage and aloe vera, to enhance thermal and structural performance while promoting eco-friendly construction practices. The objective is to analyze their effects on physical, mechanical, and thermal properties to optimize mixture design. Methods/Analysis: Six lightweight concrete mixtures were prepared using varying dosages of tuff, expanded clay, nopal mucilage, and aloe vera as lightweight and stabilizing agents. To assess their performance, a series of physical tests (bulk density, water absorption, and slump), mechanical tests (compressive strength), and thermal characterizations (conductivity, heat capacity, and resistivity) were conducted. Fractal analysis was employed to evaluate the structural complexity of the mixtures. Findings: The results revealed significant differences based on the materials used. Mixtures with aloe vera exhibited extreme water absorption (up to 11.472%) and varying consistency, from fluid (“spreads”) with tuff to workable with expanded clay. When combined with expanded clay, Nopal mucilage-based mixtures showed lower workability but higher compressive strengths (up to 11.447 MPa). Expanded clay increased bulk density and enhanced thermal efficiency, with mixtures incorporating aloe vera or nopal mucilage demonstrating high heat retention and structural complexity. The compressive strengths ranged from 7.343 MPa (aloe vera-tuff) to 12.207 MPa (water-tuff), highlighting the impact of stabilizing agents on mechanical performance. Novelty or Improvement: This study introduces a novel evaluation of lightweight concrete mixtures using nopal mucilage and aloe vera, focusing on their synergistic effects with lightweight aggregates such as tuff and expanded clay. The findings provide valuable insights into optimizing eco-friendly concrete mixtures with improved thermal retention, workability, and mechanical properties, offering a sustainable alternative for modern construction.

A Gaussian mixture model (GMM) was implemented to investigate the relationship between the liquid holdup (in various parts of the flow) and the pressure for different experimental realizations of high-viscosity gas–liquid flows. We considered a Newtonian fluid with a constant viscosity of 6 Pa s (600 cP) under a laboratory-controlled temperature. Because the pressure and the holdup do not exhibit a clear-cut relationship in the time domain, a supervised classification algorithm and a “deep” neural network (DNN) were first applied to classify the data points and predict average holdup values. Then, the GMM was applied to determine the holdup in various liquid aggregation structures of the flow as a function of the pressure. The growth rates of the cumulative lengths of the liquid structures (i.e., slug body, mixing front, and liquid film) and the gas bubbles were obtained. The GMM predicted holdup values were in close agreement with the experimental data.

Lightweight concrete is a promising alternative in modern construction due to its reduced weight and potential to improve thermal and structural efficiency. Incorporating sustainable materials, such as nopal mucilage and aloe vera, can optimize its properties, promoting more eco-friendly practices in the industry. This study evaluates six concrete mixtures using different dosages of tuff, expanded clay, nopal mucilage, and aloe vera. Physical and mechanical tests were conducted, and the results revealed varied behaviors: mixtures with aloe vera showed extremes in water absorption and consistency, with tuff being very fluid and expanded clay having good workability. Mixtures with nopal mucilage were drier and less workable. In contrast, mixtures with expanded clay showed higher bulk density and variations in consistency and water absorption. Compressive strength varied depending on the lightweight agents used: mixtures with nopal mucilage-expanded clay and aloe vera-expanded clay showed moderate strengths, suggesting that these combinations can improve the strength of lightweight concrete. The different lightweight agents also affected the thermal and physical properties and the fractal dimension of the mixtures, indicating a greater structural complexity and better heat retention in combinations of expanded clay with nopal mucilage or aloe vera.