Barrett B.,University of Arizona |
Kruse M.,University of Arizona |
Lisetskiy A.,Mintec Inc. |
Navratil P.,Lawrence Livermore National Laboratory |
And 2 more authors.
Journal of Physics: Conference Series | Year: 2011
The No Core Shell Model (NCSM) is an ab initio method for calculating the properties of atomic nuclei, starting with the fundamental interactions among the nucleons and treating all A nucleons as being active. This approach has been successfully applied to nuclei with A ≤ 20, but it is difficult to treat heavier mass nuclei with existing computer technology, because of the extemely large basis spaces required to obtain converged results. In this presentation we outline a new formalism for extending the NCSM to heavier mass nuclei. It involves using the NCSM approach to determine the core, one-body and two-body (and perhaps also three-body) terms, which are the usual input for standard shell model (SSM) calculations. Such SSM calculations can be easily performed for sd- and pf-shell nuclei. As a test of this new formalism, we apply it to nuclei in the 0p-shell, for which exact NCSM calculations can also be performed for making comparisons. Results are given both for energy spectra and electromagnetic properties.
Budhu M.,University of Arizona |
Ossai R.,University of Arizona |
Ossai R.,Mintec Inc. |
Adiyaman I.,University of Arizona |
Adiyaman I.,Tolunay Wong Engineers Inc.
Journal of Hydrologic Engineering | Year: 2014
This paper deals with ground response to surface water infiltration from an aquifer storage and recovery facility in Arizona. It presents a coupled groundwater flow-soil deformation model to investigate the role of low-hydraulic conductive materials (LHCMs), such as clays and silts, on the spatial and temporal flow and ground response. Finite element analyses were conducted that simulated the flow from surface injection ponds into the ground with and without LHCMs. The results showed that the presence of LHCMs significantly influences the flow path and the ground surface deformation profile. © 2014 American Society of Civil Engineers.
Quade J.,University of Arizona |
Dettinger M.P.,University of Arizona |
Carrapa B.,University of Arizona |
DeCelles P.,University of Arizona |
And 6 more authors.
Memoir of the Geological Society of America | Year: 2015
We synthesize geologic observations with new isotopic evidence for the timing and magnitude of uplift for the central Andes between 22°S and 26°S since the Paleocene. To estimate paleoelevations, we used the stable isotopic composition of carbonates and volcanic glass, combined with another paleoelevation indicator for the central Andes: the distribution of evaporites. Paleoelevation reconstruction using clumped isotope paleothermometry failed due to resetting during burial. The Andes at this latitude rose and broadened eastward in three stages during the Cenozoic. The first, in what is broadly termed the "Incaic" orogeny, ended by the late Eocene, when magmatism and deformation had elevated to ≥4 km the bulk (∼50%) of what is now the western and central Andes. The second stage witnessed the gradual building of the easternmost Puna and Eastern Cordillera, starting with deformation as early as 38 Ma, to >3 km by no later than 15 Ma. The proximal portions of the Paleogene foreland basin system were incorporated into the orogenic edifice, and basins internal to the orogen were enclosed and isolated from easterly moisture sources, promoting the precipitation of evaporites. In the third orogenic stage during the Pliocene-Pleistocene, Andean deformation accelerated and stepped eastward to form the modern Subandes, accounting for the final ∼15%-20% of the current cross section of the Andes. About 0.5 km of elevation was added unevenly to the Western Cordillera and Puna from 10 to 2 Ma by voluminous volcanism. The two largest episodes of uplift and eastward propagation of the orogenic front and of the foreland flexural wave, ca. 50 (?)-40 Ma and <5 Ma, overlap with or immediately postdate periods of very rapid plate convergence, high flux magmatism in the magmatic arc, and crustal thickening. Uplift does not correlate with a hypothesized mantle lithospheric foundering event in the early Oligocene. Development of hyperaridity in the Atacama Desert by the mid-Miocene postdates the twostep elevation gain to >3 km of most (∼75%) of the Andes. Hence, the record suggests that hyperarid climate was a consequence, not major cause, of uplift through trench sediment starvation. © 2014 The Geological Society of America. All rights reserved.
Dutta S.,Mintec Inc. |
Bandopadhyay S.,University of Alaska Fairbanks |
Misra D.,University of Alaska Fairbanks
Application of Computers and Operations Research in the Mineral Industry - Proceedings of the 37th International Symposium, APCOM 2015 | Year: 2015
Geostatistical methods have been used in ore reserve estimation for decades. In the recent past, neural networks and accompanying statistical methodologies for pre-processing and post-processing the data have been applied to ore-reserve estimation problems. Although neural networks show great promise in the estimation of ore reserves, application of the methodology to practical scenarios has led to results that have a low degree of confidence. The major reasons for low-confidence results when using the neural network approach are (1) lack of transparency in the model structure, (2) high sensitivity of the neural network to noise in the data, and (3) the influence of extreme values on model results. Apart from deficiencies inherent in methods such as neural networks, model application can be further weakened by a poor choice of the training and validation approach and by segmentation of the data into separate datasets, using approaches that lack scientific reasoning. In the present research, support vector machines were applied to datasets that were created using clustering algorithms. In earlier studies, ore reserve estimation was performed using datasets ("fish blocks") that were created through manual disaggregation of the entire Nome offshore placer gold dataset. To reduce any errors that might have been introduced due to the former approach to dataset creation, clustering algorithms were used. The k-means algorithm and fuzzy c-means algorithm were used to disaggregate the entire dataset. Upon careful inspection of the model results, the fuzzy c-means approach with an optimal number of nine clusters was used. The support vector machines showed improved performance on the clustered datasets as compared with the fish blocks.
Cai W.,Mintec Inc.
Mining Engineering | Year: 2011
This paper describes the development of a life-of-mine schedule (LOM) for one of the world's largest known sedimentary copper-cobalt districts located in the Katanga Province, Democratic Republic of Congo (DRC). A particular feature of the Tenke Fungurume LOM schedule is the considerable number of pits/phases for scheduling, each competing to provide the best ore available to a capacity-constrained process facility. This paper discusses the LOM scheduling objectives and constraints, data preprocessing steps such as ore binning, block aggregation and clustering analysis as a scheduling aid, the mine scheduling approach and results and conclusions.