Two dimensional computational fluid dynamics model of pollutant transport in an open pit mine under Arctic inversion

Thesis (M.S.) University of Alaska Fairbanks, 2012A better understanding of the microscale meteorology of deep, open pit mines is important for mineral exploitation in arctic and subarctic regions. During strong temperature inversions in the atmospheric boundary layer--which are common in arctic regions during the winter--the concentrations of gaseous pollutants in open pit mines can reach dangerous levels. In this research, a two dimensional computational fluid dynamics (CFD) model was used to study the atmosphere of an open pit mine. The natural airflow patterns in an open pit mine are strongly dependent on the geometry of the mine. Generally, mechanical turbulence created by the mine topography results in a recirculatory region at the bottom of the mine that is detached from the freestream. The presence of a temperature inversion further inhibits natural ventilation in open pit mines, and the air can quickly become contaminated if a source of pollution is present. Several different exhaust fan configurations were modeled to see if the pollution problem could be mitigated. The two dimensional model suggests that mitigation is possible, but the large quantity of ventilating air required would most likely beimpractical in an industrial setting.1. Introduction -- 1.1. Scientific rationale -- 1.2. Air inversion -- 1.3. Previous modeling approaches -- 1.4. Solution approaches -- 1.5. Proposed remediation measures -- 1.6. Scope of this research -- 1.7. Work plan -- 2. Data collection -- 3. Model development -- 3.1. Fundamental transport equations -- 3.2. Cell zone and boundary conditions -- 3.3. Meshing -- 3.4. Discretization -- 3.5. TurbulenceModeling -- 3.6. Geometry and mesh creation -- 3.7. Wind flow in open pit mines -- 3.8. Development of an atmospheric inversion -- 4. Pollutant transport in an open pit mine under Arctic air inversion -- 5. Mitigation of pollutants -- 5.1. Helicopter -- 5.2. Exhaust fan: 142 m³/s -- 5.3. Exhaust fan: 556 m³/s -- 5.4. Exhaust fans: multiple fans, multiple sources (142 m³/s) -- 5.5. Exhaust fans: multiple fans, multiple sources (284 m³/s) -- 6. Summary, conclusions, and recommendations for future work -- 6.1. Summary and conclusions -- 6.2. Future work -- 7. References

A New Ant Species of the Genus Tetramorium Mayr, 1855 (Hymenoptera: Formicidae) from Saudi Arabia, with a Revised Key to the Arabian Species

Tetramorium amalae sp. n. is described and illustrated from Saudi Arabia based on two worker caste specimens collected in Al Bahah region. The new species belongs to the T. shilohense group and appears to be closely related to T. dysderke Bolton from Nigeria. T. amalae is distinguished by having well-developed frontal carinae, smaller eyes, greater head length and width, greater pronotal width, and the petiole node is longer than broad. Tetramorium latinode Collingwood & Agosti is recorded for the first time from Saudi Arabia and for only the second time since the original description. The worker caste of T. latinode is redescribed and illustrated using scanning electron micrographs to facilitate recognition and the gyne is described for the first time with observations given on species relationships, biology and habitat. A revised key to the nineteen Tetramorium species recorded from Arabian Peninsula based on worker castes is provided. Tetramorium bicarinatum (Nylander) is recorded for the first time from Saudi Arabia. It is suggested that T. amalae and T. latinode are endemic to the Arabian Peninsula

Non-Supersymmetric Attractor Flow in Symmetric Spaces

We derive extremal black hole solutions for a variety of four dimensional models which, after Kaluza-Klein reduction, admit a description in terms of 3D gravity coupled to a sigma model with symmetric target space. The solutions are in correspondence with certain nilpotent generators of the isometry group. In particular, we provide the exact solution for a non-BPS black hole with generic charges and asymptotic moduli in N=2 supergravity coupled to one vector multiplet. Multi-centered solutions can also be generated with this technique. It is shown that the non-supersymmetric solutions lack the intricate moduli space of bound configurations that are typical of the supersymmetric case.Comment: 50 pages, 4 figures; v2: Reference added. To appear in JHE

Multiple Hamiltonian structure of Bogoyavlensky-Toda lattices

This paper is mainly a review of the multi--Hamiltonian nature of Toda and generalized Toda lattices corresponding to the classical simple Lie groups but it includes also some new results. The areas investigated include master symmetries, recursion operators, higher Poisson brackets, invariants and group symmetries for the systems. In addition to the positive hierarchy we also consider the negative hierarchy which is crucial in establishing the bi--Hamiltonian structure for each particular simple Lie group. Finally, we include some results on point and Noether symmetries and an interesting connection with the exponents of simple Lie groups. The case of exceptional simple Lie groups is still an open problem.Comment: 65 pages, 67 reference

On all possible static spherically symmetric EYM solitons and black holes

We prove local existence and uniqueness of static spherically symmetric solutions of the Einstein-Yang-Mills equations for any action of the rotation group (or SU(2)) by automorphisms of a principal bundle over space-time whose structure group is a compact semisimple Lie group G. These actions are characterized by a vector in the Cartan subalgebra of g and are called regular if the vector lies in the interior of a Weyl chamber. In the irregular cases (the majority for larger gauge groups) the boundary value problem that results for possible asymptotically flat soliton or black hole solutions is more complicated than in the previously discussed regular cases. In particular, there is no longer a gauge choice possible in general so that the Yang-Mills potential can be given by just real-valued functions. We prove the local existence of regular solutions near the singularities of the system at the center, the black hole horizon, and at infinity, establish the parameters that characterize these local solutions, and discuss the set of possible actions and the numerical methods necessary to search for global solutions. That some special global solutions exist is easily derived from the fact that su(2) is a subalgebra of any compact semisimple Lie algebra. But the set of less trivial global solutions remains to be explored.Comment: 26 pages, 2 figures, LaTeX, misprints corrected, 1 reference adde

There are no magnetically charged particle-like solutions of the Einstein Yang-Mills equations for Abelian models

We prove that there are no magnetically charged particle-like solutions for Abelian models in Einstein Yang-Mills, but for non-Abelian models the possibility remains open. An analysis of the Lie algebraic structure of the Yang-Mills fields is essential to our results. In one key step of our analysis we use invariant polynomials to determine which orbits of the gauge group contain the possible asymptotic Yang-Mills field configurations. Together with a new horizontal/vertical space decomposition of the Yang-Mills fields this enables us to overcome some obstacles and complete a dynamical system existence theorem for asymptotic solutions with nonzero total magnetic charge. We then prove that these solutions cannot be extended globally for Abelian models and begin an investigation of the details for non-Abelian models.Comment: 48 pages, 1 figur

An exploration of the effectiveness of artificial mini-magnetospheres as a potential solar storm shelter for long term human space missions

If mankind is to explore the solar system beyond the confines of our Earth and Moon the problem of radiation protection must be addressed. Galactic cosmic rays and highly variable energetic solar particles are an ever-present hazard in interplanetary space. Electric and/or magnetic fields have been suggested as deflection shields in the past, but these treated space as an empty vacuum. In fact it is not empty. Space contains a plasma known as the solar wind; a constant flow of protons and electrons coming from the Sun. In this paper we explore the effectiveness of a “mini-magnetosphere” acting as a radiation protection shield. We explicitly include the plasma physics necessary to account for the solar wind and its induced effects. We show that, by capturing/containing this plasma, we enhance the effectiveness of the shield. Further evidence to support our conclusions can be obtained from studying naturally occurring “mini-magnetospheres” on the Moon. These magnetic anomalies (related to “lunar swirls”) exhibit many of the effects seen in laboratory experiments and computer simulations. If shown to be feasible, this technology could become the gateway to manned exploration of interplanetary space

Metal ion binding to the amyloid beta monomer studied by native top-down FTICR mass spectrometry

Native top-down mass spectrometry is a fast, robust biophysical technique that can provide molecular-scale information on the interaction between proteins or peptides and ligands, including metal cations. Here we have analyzed complexes of the full-length amyloid β (1-42) monomer with a range of (patho)physiologically relevant metal cations using native Fourier transform ion cyclotron resonance mass spectrometry and three different fragmentation methods—collision-induced dissociation, electron capture dissociation, and infrared multiphoton dissociation—all yielding consistent results. Amyloid β is of particular interest as its oligomerization and aggregation are major events in the etiology of Alzheimer’s disease, and it is known that interactions between the peptide and bioavailable metal cations have the potential to significantly damage neurons. Those metals which exhibited the strongest binding to the peptide (Cu2+, Co2+, Ni2+) all shared a very similar binding region containing two of the histidine residues near the N-terminus (His6, His13). Notably, Fe3+ bound to the peptide only when stabilized toward hydrolysis, aggregation, and precipitation by a chelating ligand, binding in the region between Ser8 and Gly25. We also identified two additional binding regions near the flexible, hydrophobic C-terminus, where other metals (Mg2+, Ca2+, Mn2+, Na+, and K+) bound more weakly—one centered on Leu34, and one on Gly38. Unexpectedly, collisional activation of the complex formed between the peptide and [CoIII(NH3)6]3+ induced gas-phase reduction of the metal to CoII, allowing the peptide to fragment via radical-based dissociation pathways. This work demonstrates how native mass spectrometry can provide new insights into the interactions between amyloid β and metal cations

On classical finite and affine W-algebras

This paper is meant to be a short review and summary of recent results on the structure of finite and affine classical W-algebras, and the application of the latter to the theory of generalized Drinfeld-Sokolov hierarchies.Comment: 12 page