Linear and spatial variability of eucalyptus dendrometric attributes correlated with the properties of a Typic Haplustox soil (Oxisol) in the Brazilian savannah

Effects of soil attributes using the geostatistical tool improves the interpretation of specific soil management. Thus, this study aimed to evaluate the physical, chemical, and microbiological properties of a Typical Haplustox (Oxisol), identifying those with the best linear and spatial correlation with eucalyptus (Eucalyptus spp.) vegetative growth. The experiment was conducted at the Teaching, Research, and Extension Farm (FEPE) of the Universidade Estadual Paulista (UNESP), Campus of Ilha Solteira. Thirty-five points spaced 13 meters apart were demarcated for analysis, which were distributed in 5 rows of 7 points each. From each point, 2 soil samples were collected from the 0-10 cm depth layer. The physical, chemical, and microbiological soil properties evaluated were: sand, silt, and clay contents; penetration resistance (PR), gravimetric moisture (GM), real density (RD), microbial biomass carbon (MBC), respirometry (CO2-C), metabolic quotient (qCO2), organic matter content (OM), and hydrogenionic potential (pH). The eucalyptus attributes assessed were: plant height (PH) and circumference at breast height (CBH). Each attribute was analyzed by descriptive statistics using the SAS software. Data frequency distribution was verified by the Shapiro Wilk method, and geospatial changes were analyzed by the GS+ software. The soil property that best explained the variability in eucalyptus dendrometric attributes was real density (RD). Except for RD, all properties did not show spatial dependence (i.e., pure nugget effect), which significantly represents eucalyptus vegetative performance.

The use of glass waste cullet in the concrete production as an important factor in the circular economy

The paper focuses on the use of glass waste as a substitute for aggregates (0/4, 4/8 and 8/16 mm) in the production of concrete in order to reduce the negative impact of existing waste on the environment. For the study, 5 mixtures were designed with gradual replacement of individual natural aggregate fractions in the concrete mixture by glass cullet. Real density, total water absorption and compressive strength were monitored on cubes with an edge of 100 mm for a period of 14 days to 3 years. The achieved compressive strength of samples with glass as a filler at the level of 50 MPa gives a good precondition for the real use of such concrete in practice. In addition, when combined it with lower real density and total water absorption.

Physico-Chemical Characterization of Soil in a Tropical Landscape Restored by a Vegetal Succession

The objective was to evaluate the physicochemical composition of soils and their relationship with successional vegetation. The study was conducted in the area of influence of fluvial volcanic muds in the central region of Colombia. The physical variables of texture, porosity, humidity, color, apparent density, real density; and chemical variables of pH, organic matter, cation exchange capacity, major elements, minor elements, Al saturation, base saturation, Ca/Mg relation, (Ca+Mg)/K relation, and Mg/K relation were analyzed. A multivariate analysis between variables and descriptive of the soil–vegetation relationship was carried out. Physically, there was a negative correlation between apparent density with %porosity and real density with humidity content. The texture was classified as sandy loam and the structure as granular-crumbly type. Chemically, there was a negative correlation between pH, Mg/K relation, (Ca+Mg)/K relation, and Al saturation; a positive correlation between P, Mn, Ca, Zn, Fe, Mg, and base saturation. Furthermore, Na and K did not show any interaction relationship. The predominant plant species are distributed in the families Fabaceae, Asteraceae, Malvaceae, Euphorbiaceae, Cyperaceae, and Poaceae. The physical and chemical characteristics of the soil present conditions that allow the establishment and continuation of successional vegetation with a dominance of tree and shrub growth habit.

A Tangent-Line Approach for Effective Density Used in the Ideal Mixing Rule: Part II—Evaluation of Mixing Characteristics of Oil/Gas Systems and Application Criteria

Summary Although in Part I of this study (Chen and Yang 2020) we developed a tangent-line approach for effective density that is more general, robust, and flexible than the methods proposed by Saryazdi (2012) and Saryazdi et al. (2013), its application is only limited to heavy-oil/bitumen-associated mixtures [i.e., specifically, it has only been applied to bitumen-rich liquid phase (denoted as L2)]. As indicated in Part I, the density of nitrogen (N2)/hydrocarbon mixtures cannot be accurately predicted by using the ideal mixing rule (IM) with either real density or effective density. Not only do we need to explain and evaluate the observed deviations and patterns, but also the density prediction of solvent/Fraction 1 systems [i.e., Fraction 1 of the Athabasca bitumen, which has a molecular weight (MW) of 268.8 g/mol, as reported in Azinfar et al. (2018a, 2018b, 2018c)] needs to be improved for practical use. In this study, we evaluate the mixing characteristics of different molecules in a mixture using the tangent-line approach. By evaluating and comparing performances of the IM with effective density (IM-E) and the IM with real density (IM-R), the observed patterns and deviations together with those calculated from the Westman equation indicate that the oil/gas molecules somewhat behave like solid particles in mixing. Accordingly, we further modify the effective density used in the IM to bridge the gap between the IM-E and the IM-R. The database has been extended to light-oil/gas systems such as black oils, volatile oils, gas condensates, carbon dioxide (CO2) miscible fluids, sour gases, and wet/dry gases. The IM with modified effective density (IM-ME) has also been applied to solvent/Fraction 1 systems and the C2 or C3 or n-C4-extraction L1 phase (bitumen-related mixtures) with better accuracy. Also, we develop new criteria for the uses of the IM-E, IM-ME, and IM-R that can cover the density predictions for almost all types of oil/gas systems in the petroleum industry with high accuracy. The performances of the IM are thoroughly evaluated and compared with the volume-translated (VT) Peng-Robinson equation of state (EOS) (VT PR EOS), from which the deviations provide new insights for accurately quantifying the mixture density in a more robust and reliable manner.

Solidification Analysis of Density-Graded Closed-Cell Metallic Foam Under Constant Temperature Boundary Condition

In the industrial fabrication processes of density-graded closed-cell metallic foams, it is of great importance to control the solidification immediately after foams are formed so as to obtain the final products with well distributed density-graded pores and less defects. This paper presented an analytical work aiming to predict the solidification front of density-graded metallic foam under constant temperature boundary condition. Numerical simulations based on ideal density-graded circular pores demonstrated good agreement with the analytical solutions. The 2D porous morphology of a real density-graded aluminum foam was further reconstructed with microCT, on the basis of which the propagation of solidification front inside this real density-graded foam was numerically investigated. An equivalent shape factor for this real foam was calculated to provide an insight for the influence of different pore shapes on solidification. Compared with other pores, the solidification speed of elliptical pores (a common pore shape in real foams) is moderate, i.e., slower than circular pores but quicker than triangular pores for same porosity.