Effects of intermittent irrigation on the extraction of copper from heap bioleaching systems.

Includes bibliographical references.The use of microorganisms for the regeneration of leach agents in the heap leaching of mineral sulfide ores is finding increasing application as a hydrometallurgical unit operation applicable to the treatment of the increasing low grade ores. These same microorganisms contribute to the formation of acid rock drainage (ARD) through the oxidation of base metal sulfides, particularly pyrite. In this research, the effect of intermittent irrigation on the extraction of copper and iron from a low grade chalcopyrite ore in the heap bioleaching system is investigated and compared with the effect under abiotic conditions. As a secondary investigation, the effect of the introduction of layers of fines, which may develop during the course of the operation of heaps, on copper extraction in heap bioleaching systems was also researched

A Comparison of Neural Activity for Peripersonal and Extrapersonal Viewing in Real and Virtual Environments

This study involved a series of tests comparing the similarities and differences in neural activity at a subject’s peripheral and extrapersonal space in the real environment and virtual reality. We hypothesized that there would be similar brain activity at each of these environments depending on the focal distance of an object from the participant. Peripheral space is the visual space that is a reachable distance from a person. It has an overall neural pattern in the dorsal stream of the brain. Extrapersonal space is the visual space that does not directly surround a person and cannot be directly acted on. The overall neural pattern involved is in the ventral stream of the brain. In virtual reality, a person is able to interact with the virtual world presented just as they would with the real-world environment. They experience peripheral and extrapersonal space even though the device they wear is only inches away from their eyes. Data in this experiment was taken using electroencephalography (EEG). It was processed and analyzed using EEGLAB, a program of the computer software MATLAB. After data analysis, it was found that in the real environment and virtual reality in a person’s peripersonal space, there was neural activity in the intraparietal cortex of the brain and along the dorsal pathway of the brain. When studying visual perception in a person’s extrapersonal space, it was found that in the real environment and virtual reality, there was neural activity in the ventral occipital cortex and activity in the medial temporal cortex of the subject’s brain. This correlates to what we anticipated to happen after studying previous research on visual perception in the real world. In the future, we hope to be able to take data on a greater variety of participants as well as add trials studying the effect of augmented reality. This will give us an even better idea of the way the brain reacts while seeing objects at different focal distances in a variety of environments

Aggressive Communication, Parental Communication, and Sibling Communication

The family is often seen as the center of instruction for children and the base for learning communication patterns. Aggressive communication is often seen in the family, especially as a parenting method. In this thesis, the current state of available literature on aggressive communication in the family is examined. This includes parenting styles, communication relationships between one parent and one child, and the negative effects verbal aggressive communication has on children. A t-test is used to research the responses of 100 students who have verbally aggressive parents. At 2.59, the t-test supports the hypothesis that parenting communication styles concerning aggressiveness is related to the aggressive communication employed by the child in relations with his or her siblings

Aggressive Communication, Parental Communication, and Sibling Communication

The family is often seen as the center of instruction for children and the base for learning communication patterns. Aggressive communication is often seen in the family, especially as a parenting method. In this thesis, the current state of available literature on aggressive communication in the family is examined. This includes parenting styles, communication relationships between one parent and one child, and the negative effects verbal aggressive communication has on children. A t-test is used to research the responses of 100 students who have verbally aggressive parents. At 2.59, the t-test supports the hypothesis that parenting communication styles concerning aggressiveness is related to the aggressive communication employed by the child in relations with his or her siblings

Large-area visually augmented navigation for autonomous underwater vehicles

Submitted to the Joint Program in Applied Ocean Science & Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2005This thesis describes a vision-based, large-area, simultaneous localization and mapping (SLAM) algorithm that respects the low-overlap imagery constraints typical of autonomous underwater vehicles (AUVs) while exploiting the inertial sensor information that is routinely available on such platforms. We adopt a systems-level approach exploiting the complementary aspects of inertial sensing and visual perception from a calibrated pose-instrumented platform. This systems-level strategy yields a robust solution to underwater imaging that overcomes many of the unique challenges of a marine environment (e.g., unstructured terrain, low-overlap imagery, moving light source). Our large-area SLAM algorithm recursively incorporates relative-pose constraints using a view-based representation that exploits exact sparsity in the Gaussian canonical form. This sparsity allows for efficient O(n) update complexity in the number of images composing the view-based map by utilizing recent multilevel relaxation techniques. We show that our algorithmic formulation is inherently sparse unlike other feature-based canonical SLAM algorithms, which impose sparseness via pruning approximations. In particular, we investigate the sparsification methodology employed by sparse extended information filters (SEIFs) and offer new insight as to why, and how, its approximation can lead to inconsistencies in the estimated state errors. Lastly, we present a novel algorithm for efficiently extracting consistent marginal covariances useful for data association from the information matrix. In summary, this thesis advances the current state-of-the-art in underwater visual navigation by demonstrating end-to-end automatic processing of the largest visually navigated dataset to date using data collected from a survey of the RMS Titanic (path length over 3 km and 3100 m2 of mapped area). This accomplishment embodies the summed contributions of this thesis to several current SLAM research issues including scalability, 6 degree of freedom motion, unstructured environments, and visual perception.This work was funded in part by the CenSSIS ERC of the National Science Foundation under grant EEC-9986821, in part by the Woods Hole Oceanographic Institution through a grant from the Penzance Foundation, and in part by a NDSEG Fellowship awarded through the Department of Defense