Integral models for bubble,droplet, and multiphase plume dynamics in stratification and crossflow

We present the development and validation of a numerical modeling suite for bubble and droplet dynamics of multiphase plumes in the environment. This modeling suite includes real-fluid equations of state, Lagrangian particle tracking, and two different integral plume models: an Eulerian model for a double-plume integral model in quiescent stratification and a Lagrangian integral model for multiphase plumes in stratified crossflows. Here, we report a particle tracking algorithm for dispersed-phase particles within the Lagrangian integral plume model and a comprehensive validation of the Lagrangian plume model for single- and multiphase buoyant jets. The model utilizes literature values for all entrainment and spreading coefficients and has one remaining calibration parameter \( \kappa \), which reduces the buoyant force of dispersed phase particles as they approach the edge of a Lagrangian plume element, eventually separating from the plume as it bends over in a crossflow. We report the calibrated form \( \kappa = [(b - r) / b]^4 \), where b is the plume half-width, and r is the distance of a particle from the plume centerline. We apply the validated modeling suite to simulate two test cases of a subsea oil well blowout in a stratification-dominated crossflow. These tests confirm that errors from overlapping plume elements in the Lagrangian integral model during intrusion formation for a weak crossflow are negligible for predicting intrusion depth and the fate of oil droplets in the plume. The Lagrangian integral model has the added advantages of being able to account for entrainment from an arbitrary crossflow, predict the intrusion of small gas bubbles and oil droplets when appropriate, and track the pathways of individual bubbles and droplets after they separate from the main plume or intrusion layer.     

Testing the developmental stress hypothesis in canaries: consequences of nutritional stress on adult song phenotype and mate attractiveness

The complex songs of songbirds are thought to have evolved through sexual selection. Sexually selected signals must be associated with costs in order to ensure their honesty as indicator of male quality. Costs may relate to the development of the neural substrate underlying song learning, which develops already very early in life. Song may, therefore, serve as an indicator of the early developmental history. This nutritional stress hypothesis has initially been confirmed for a variety of species, but recent studies using zebra finches as a model species reported somewhat inconsistent effects, and the functional consequences of changes in adult song phenotype remain unclear. We tested the nutritional stress hypothesis in canaries by manipulating either the brood size or the food quality postfledging. The brood size manipulation had a significant effect on early development, and low food quality postfledging led to a transient reduction in body mass. However, we did not find evidence that any of the song traits measured reflected the early developmental conditions, which is in conflict with the nutritional stress hypothesis. Canaries may be less vulnerable to nutritional stress or are able to compensate stressful conditions during early development. However, if males compensated, this compensation may have come at a survival cost. Female mate choice decisions were independent of the developmental history of a male. Instead, females preferred males singing longer song bouts, a trait that may contain a heritable component.     

Societal implications of a changing Arctic Ocean

The Arctic Ocean is undergoing rapid change: sea ice is being lost, waters are warming, coastlines are eroding, species are moving into new areas, and more. This paper explores the many ways that a changing Arctic Ocean affects societies in the Arctic and around the world. In the Arctic, Indigenous Peoples are again seeing their food security threatened and cultural continuity in danger of disruption. Resource development is increasing as is interest in tourism and possibilities for trans-Arctic maritime trade, creating new opportunities and also new stresses. Beyond the Arctic, changes in sea ice affect mid-latitude weather, and Arctic economic opportunities may re-shape commodities and transportation markets. Rising interest in the Arctic is also raising geopolitical tensions about the region. What happens next depends in large part on the choices made within and beyond the Arctic concerning global climate change and industrial policies and Arctic ecosystems and cultures.     

Climate change impacts on tree crop suitability in Southeast Asia

Regional Environmental Change - Understanding popular attitudes to climate change can be important in developing effective climate adaptation responses. However, in the Pacific region, which is at...     

Does corporate social performance reduce greenhouse gas emissions at the macro level?

Corporate social performance (CSP) is assumed to have a positive impact on macroeconomic sustainability, but empirical evidence of this impact is absent in the literature. The objective of this paper is to investigate the macro impacts of CSP. We first establish a conceptual framework on the relationship between CSP at the individual business level and sustainability at the macro level. Next, we empirically test the relationship between (averaged) CSP scores and greenhouse gas emissions at the macro level for 22 countries during 2004–2011. We use Granger causality tests to check for Granger causality. The estimation results show that CSP reduces greenhouse gas emissions, but the long-term effect is rather modest.     

Aqueous extracts of Mozambican plants as alternative and environmentally safe acid-base indicators

Indicators are substances that change color as the pH of the medium. Many of these substances are dyes of synthetic origin. The mulala plant (Euclea natalensis), which roots are commonly used by rural communities for their oral hygiene, and roseira (Hibiscus rosa-sinensis), an ornamental plant, are abundant in Mozambique. Currently, synthetic acid-base indicators are most commonly used but have environmental implications and, on the other hand, are expensive products, so the demand for natural indicators started. This study investigated the applicability of aqueous extracts of H. rosa-sinensis and E. natalensis as acid-base indicators. Ground on this work, the extracts can be used as acid-base indicators. On the basis of the absorption spectroscopy in both the UV-Vis region and previous studies, it was possible to preliminarily pinpoint anthocyanins and naphthoquinones as responsible for the shifting of colors depending on the pH range of aqueous extracts of H. rosa-sinensis and E. natalensis. These natural indicators are easily accessible, inexpensive, easy to extract, environmentally safe, and locally available.     

A biochar-based medium in the biofiltration system: Removal efficiency,microorganism propagation,and the medium penetration modeling

Biofiltration is a method of biological treatment belonging to cleaner technologies because it does not produce secondary air pollutants, but helps to integrate natural processes in microorganisms for decomposing volatile air pollutants and solving odor problems. The birch wood biochar has been chosen as a principal material for biofilter bed medium. The experiments were conducted at the temperatures of 24, 28, and 32 °C, while the concentration of acetone, xylene, and ammonium reached 300 mg/m³ and the flow rate was 100 m³/hr. Before passing through the stage of the experimental research into the packing material inside biofilters, microorganisms were introduced. Four strains of microorganisms (including micromycetes Aspergillus versicolor BF-4 and Cladosporium herbarum 7KA, as well as yeast Exophiala sp. BF1 and bacterium Bacillus subtilis B20) were selected. At the inlet loading rate of 120 g/m³/hr, the highest elimination capacity of xylene in the biochar-based biofilter with the inoculated medium was 103 g/m³/hr, whereas that of ammonia was 102 g/m³/hr and that of acetone was 97 g/m³/hr, respectively. The maximum removal efficiency reached 86%, 85%, and 81%, respectively. The temperature condition (though characterized by some rapid changes) can hardly have a considerable influence on the biological effect (i.e., microbiological activity) of biofiltration; however, it can cause the changes in physical properties (e.g., solubility) of the investigated compounds.

Implications: The birch biochar can be successfully used in the biofiltration system for propagation of inoculated microorganisms, biodegrading acetone, xylene, and ammonia. At the inlet loading rate of 120 g/m³/hr, the highest elimination capacity of xylene was 103 g/m³/hr, that of ammonia was 102 g/m³/hr, and that of acetone was 97 g/m³/hr, respectively. The morphological structure of biochar can be affected by the aggressive air contaminants, causing the change in the medium specific surface area, which is one of the factors controlling the biofilter performance. Although biological effects in biofiltration are typically considered to be more important than physical effects, the former may be more important for compounds with high Henry’s Law coefficient values, and the biofilter design should thus provide conditions for better compound absorption.     

Adsorption of Hydrochloric Acid on Solid Slaked Lime for Flue Gas Clean Up

The reaction between hydrochloric acid and solid slaked lime was investigated by passing simulated flue gas through a fixed bed reactor. The influence of CO₂ and H₂O present in the flue gas was studied, as well as the influence of the reaction temperature in the range 423 to 673 K. The reaction was found to be of first order with respect to the two reactants. Expressions to account for the temperature and the CO₂ and H₂O concentrations were derived from the experimental data.