Feed forward neural network and interpolation function models to predict the soil and subsurface sediments distribution in Bam,Iran

An application of the artificial neural network (ANN) approach for predicting mean grain size using electric resistivity data from Bam city is presented. A feed forward back propagation network was developed employing 45 sets of input data. The input variables in the ANN model are the electrical resistivity, water table as a Boolean value and depth; the output is the mean grain size. To demonstrate the authenticity of this approach, the network predictions are compared with those from interpolation methods and the same data. This comparison shows that the ANN approach performs better results. The predicted and observed mean grain size values were compared and show high correlation coefficients. The ANN approach maps show a high degree of correlation with well data based grain size maps and can therefore be used conservatively to better understand the influence of input parameters on sedimentological predictions.     

Application of neural networks to predict net present value in mining projects

Net present value (NPV) is the most popular economic indicator in evaluation of the investment projects. For the mining projects, this criterion is calculated under uncertainty associated with the relevant parameters of say commodity price, discount rate, etc. Accurate prediction of the NPV is a quite difficult process. This paper mainly deals with the development of a new model to predict NPV using artificial neural network (ANN) in the Zarshuran gold mine, Iran. Gold price (as the main product), silver price (as the byproduct), and discount rate were considered as input parameters for the ANN model. To reach an optimum architecture, different types of networks were examined on the basis of a trial and error mechanism. A neural network with architecture 3-15-10-1 and root mean square error of 0.092 is found to be optimum. Prediction capability of the proposed model was examined through computing determination coefficient (R ²?=?0.987) between predicted and real NPVs. Absolute error of US$0.1 million and relative error of 1.4 % also confirmed powerfulness of the developed ANN model. According to sensitivity analysis, it was observed that the gold price is the most effective and discount rate is the least effective parameter on the NPV.     

Geochemistry of the Zargoli granite: Implications for development of the Sistan Suture Zone,southeastern Iran

The Zargoli granite, which extends in a northeast–southwest direction, intrudes into the Eocene–Oligocene regional metamorphic flysch‐type sediments in the northwest of Zahedan. This pluton, based on modal and geochemical classification, is composed of biotite granite and biotite granodiorite, was contaminated by country rocks during its emplacement, and is slightly changed to more aluminous. The SiO₂ content of these rocks range from 62.4 to 66 wt% with an alumina saturation index of Shand [molar Al₂O₃/(CaO + Na₂O + K₂O)] ～ 1.1. Most of its chemical variations could be explained by fractionation or heterogeneous distribution of biotite. The features of the rocks resemble those which are typical to post‐collisional granitoids. Chondrite‐normalized rare‐earth element patterns of these rocks are fractionated at (La/Lu)_N = 2.25–11.82 with a pronounced negative Eu anomaly (Eu/Eu* = 3.25–5.26). Zircon saturation thermometry provides a good estimation of magma temperatures (767.4–789.3°C) for zircon crystallization. These characteristics together with the moderate Mg# [100Mg/(Mg + Fe)] values (44–55), Fe + Mg + Ti (millications) = 130–175, and Al–(Na + K + 2Ca) (millications) = 5–50 may suggest that these rocks have been derived from the dehydration partial melting of quartz–feldspathic meta‐igneous lower crust.     

High-resolution Observations of H$\alpha$ Spectra with a Subtractive Double Pass

High-resolution imaging spectroscopy in solar physics has relied on Fabry–Pérot interferometers (FPIs) in recent years. FPI systems, however, become technically challenging and expensive for telescopes larger than the 1 m class. A conventional slit spectrograph with a diffraction-limited performance over a large field of view (FOV) can be built at much lower cost and effort. It can be converted into an imaging spectro(polari)meter using the concept of a subtractive double pass (SDP). We demonstrate that an SDP system can reach a similar performance as FPI-based systems with a high spatial and moderate spectral resolution across a FOV of \(100^{\prime\prime} \times100^{\prime \prime}\) with a spectral coverage of 1 nm. We use H\(\alpha\) spectra taken with an SDP system at the Dunn Solar Telescope and complementary full-disc data to infer the properties of small-scale superpenumbral filaments. We find that the majority of all filaments end in patches of opposite-polarity fields. The internal fine-structure in the line-core intensity of H\(\alpha\) at spatial scales of about 0\(.\!\!^{\prime \prime }\)5 exceeds that in other parameters such as the line width, indicating small-scale opacity effects in a larger-scale structure with common properties. We conclude that SDP systems in combination with (multi-conjugate) adaptive optics are a valid alternative to FPI systems when high spatial resolution and a large FOV are required. They can also reach a cadence that is comparable to that of FPI systems, while providing a much larger spectral range and a simultaneous multi-line capability.     

SOM-DRASTIC: using self-organizing map for evaluating groundwater potential to pollution

Groundwater is considered as the most important water resource, especially in arid and semi-arid regions, so it is crucial to impede this source of water to be contaminated. One of the most common methods to assess groundwater vulnerability is DRASTIC method. However, the subjectivity existing in defining DRASTIC weights and ratings as well as inadaptability of the parameters involved in this method with special geology, hydrogeology, land use and climatic conditions have urged researchers to modify this method. In this paper, a new method combining a special type of the neural networks called Self-Organizing Map (SOM) and the traditional DRASTIC model resulting in the hybrid SOM-DRASTIC model is applied to modify and improve DRASTIC Model. The traditional DRASTIC method holds a summation among all negative effects of different factors contributing to vulnerability, while the proposed hybrid method is able of classifying the groundwater vulnerability and deriving the real relation existing between the DRASTIC parameters as the inputs and the vulnerability class as the output of the method. The vulnerability assessment process was performed on the Zayandeh-Rud river basin aquifers in Iran. The SOM-DRASTIC identified the northern parts of the study area as the most vulnerable areas with a drastically fractured structure, while the traditional DRASTIC ranked the western parts as the most vulnerable regions with a high rate of net recharge. The results demonstrate that the proposed method can be used by managers and decision-makers as an alternative robust tool for vulnerability-based classification and land use planning.     

Modeling Fate and Transport of Volatile Organic Compounds (VOCs) Inside Sewer Systems

Hazardous waste site investigations have shown that volatile organic compounds (VOCs) can be transported via sewer pipes and migrate into indoor spaces. Despite field data confirming the presence of this exposure pathway, there is lack of context-based numerical models that provide guidance to characterize and predict VOCs concentration in sewer gas at vapor intrusion sites. Particularly, this poses a challenge when assessing and mitigating risks associated with these exposure pathways. Therefore, a numerical model has been developed to simulate the concentration of VOCs in sewer gas in different stages throughout the sewer lines. The developed model considers various input parameters, including temperature, sewer liquid depth, groundwater depth, and sewer construction characteristics to incorporate local and operational conditions. The model's output is verified using field data from a sewer system constructed near a Superfund site. Moreover, a sensitivity analysis was conducted to evaluate the model's response to variation of the external input parameters. To the best of our knowledge, this study is the first attempt to model VOCs concentration in sewer gas, particularly to address vapor intrusion. The developed model can be used as a numerical tool to support the development of sewer assessment guidelines, risk assessment studies, and mitigation strategies.     

The role of emerging bipoles in the formation of a sunspot penumbra

The generation of magnetic flux in the solar interior and its transport from the convection zone into the photosphere, the chromosphere, and the corona will be in the focus of solar physics research for the next decades. With 4 m class telescopes, one plans to measure essential processes of radiative magneto‐hydrodynamics that are needed to understand the nature of solar magnetic fields. One key‐ingredient to understand the behavior of solar magnetic field is the process of flux emergence into the solar photosphere, and how the magnetic flux reorganizes to form the magnetic phenomena of active regions like sunspots and pores. Here, we present a spectropolarimetric and imaging data set from a region of emerging magnetic flux, in which a proto‐spot without penumbra forms a penumbra. During the formation of the penumbra the area and the magnetic flux of the spot increases. First results of our data analysis demonstrate that the additional magnetic flux, which contributes to the increasing area of the penumbra, is supplied by the region of emerging magnetic flux. We observe emerging bipoles that are aligned such that the spot polarity is closer to the spot. As an emerging bipole separates, the pole of the spot polarity migrates towards the spot, and finally merges with it. We speculate that this is a fundamental process, which makes the sunspot accumulate magnetic flux. As more and more flux is accumulated a penumbra forms and transforms the proto‐spot into a full‐fledged sunspot (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Seismic behavior of coupled steel plate shear walls with simple boundary frame connections

The coupled steel plate shear wall (C-SPSW) configuration has been investigated by researchers as a means of improving the overturning stiffness and architectural flexibility of SPSW structures. While C-SPSWs have been shown to exhibit excellent seismic performance, the fabrication cost associated with the high number of moment-resisting connections used in such systems is a potential detraction to their use as an economical solution. Past research has shown that the hysteresis response of SPSWs with simple frame connections is significantly pinched, and as such, most seismic codes prohibit their use in high seismic areas. However, when used in the C-SPSW configuration, a dual system is formed in which the coupling beams not only improve resistance to overturning but also provide substantial lateral strength and energy dissipation capacity. This paper presents an exploration of the potential to improve the economy of C-SPSWs by using the simple boundary frame connections. First, employing the principles of plastic analysis, an attempt is made to quantify the contribution of the coupling beams to the overall lateral load resistance of the system. Then, to evaluate the seismic performance of such C-SPSW systems and allow for the comparison with that of the C-SPSWs with rigid frames, several prototypes are designed and analyzed using a series of nonlinear response history and pushover analyses. The results indicated that the C-SPSWs with simple boundary frames exhibited satisfactory seismic performance comparable with that of the C-SPSWs with rigid frames under both the 10/50 and 2/50 hazard levels, while allowing for reduced fabrication costs.     

Interaction of a Fresh Water Lake and a Karstic Spring via a Syncline Fold

Kaftar Lake is a high‐altitude fresh water lake located in High Zagros, south of Iran. Despite the high annual evaporation to precipitation ratio in the area, lake water electrical conductivity is usually lower than 1000 µS/cm, this may be due to high seepage from the floor of the lake. Therefore, the hypothesis of possible underground connections between Namdan Basin, where the lake is located, and the surrounding basins with lower elevation (Aspas and Dehbid Basins) was investigated. Hydrogeology, hydrochemistry, and stable isotopes data of the lake and surrounding basins along with the lake water balance study were applied to test the hypothesis. Results indicate that Kaftar Lake has no connection with Aspas Basin in south, but it is hydraulically connected to Dehbid Basin. In Dehbid Basin, “Ghasr_e_Yaghoob spring” (average discharge ?1200 L/s) emerges from a small outcrop (about 0.8 km²) of Daryan limestone Formation, where this outcrop is much smaller than the required recharge area for such average discharge rate. The study shows that this spring is recharged by Kaftar Lake and Namdan Basin aquifer, through Daryan Formation of Gandboee Syncline located to the northern part of the lake.     

Genesis of the Nasirabad manganese occurrence,Fars province,Iran: Geochemical evidences

The Nasirabad manganese occurrence is located to the south of the Neyriz in the Fars province. Structurally and lithologically, this occurrence lies in the southwest part of the Zagros Thrust Belt and was deposited as Mn-nodules and interconnected ore-bearing interlayer's with radiolarite cherts in the vicinity of the Neyriz ophiolites. The present work deals with the geology and geochemistry of the Nasirabad manganese occurrence with a discussion of its genesis. High Mn/Fe (average 18.85) and high Ba (average 28,830 ppm) with low Pb (2.0 ppm) and LREE > HREE, La_n/Nd_n (average 4.5), Dy_n/Yb_n (average 1.2) and negative Eu anomaly suggest distal hydrothermal source. The Co/Zn (average 2.2), Ce/La ratio (average 0.67) and trace element discrimination diagrams indicate hydrothermal–hydrogenous processes. Y/Ho ratio (average 24.85) and strong positive correlation coefficient between major oxides and some high field strength elements (HFSE) like; TiO₂ vs Fe₂O₃ (r = 0.98), Al₂O₃ vs Zr (r = 0.97), Al₂O₃ vs Fe₂O₃ (r = 0.98), Zr vs K₂O (r = 0.98), Nb vs TiO₂ (r = 0.92), Th vs Fe₂O₃ (r = 0.76), Th vs MgO (r = 0.86) reveal the presence of volcaniclastics and (or) terrigenous detritals of mafic composition being deposited into the depositional basin. It seems that intermittent interlayering of mafic detrital material derived from volcanic eruption of the Neyriz island arc directly affected the physicochemical conditions of hydrothermal ore precipitation in this basin and consequently the Nasirabad manganese ores represent hydrothermal–hydrogenous geochemical characteristics. The Nasirabad is an example of non-sulphidic, oxic Mn-mineralization. Similar trend between the enrichment and depletion of some bioessential elements (e.g., Mn, As, Ba, Sr, Co, Ce) might have been resulted from selective sequestering of metal ions by microbial processes and hence hydrogenous characteristics may also be the result of biogenetic processes. Moreover the high dilution of distal hydrothermal exhalations by sea water cannot be ruled out.