Risk-Based Analysis in Mineral Potential Mapping: Application of Quantifier-Guided Ordered Weighted Averaging Method

Natural Resources Research - In this work, a quantifier-guided ordered weighted averaging (OWA) method was employed for mineral potential mapping (MPM) in Nowchun Cu–Mo prospect, SE Iran. The...     

Influence of Ultrasonic on the Flow Behavior and Disperse Phase of Cellulose Nano-particles at Fluid–Fluid Interface

Natural Resources Research - Nano-particles can localize at oil–water (O/W) interface, reduce residual oil saturation, increase the viscosity of brine and decrease the viscosity of crude oil...     

Effects of rotational components of earthquake on seismic response of arch concrete dams

The present study deals with dynamic analysis of arch concrete dams, taking rotational components of earthquakes into account. A modified methodology was used to evaluate the rotational components of the earthquake. The translational components of the earthquake have been used in to obtain the rotational components of the earthquake, based on the intersecting isotropic elastic wave propagation. Two rotational components of Taft, Tabas and San-Fernando earthquakes are evaluated based on the translational components of the earthquakes and considering frequency dependencies of incident angle and wave velocity. Finally, dynamic analyses of Morrow Point Dam are presented to evaluate the effects of combined translational and rotational components on the seismic response of the dam. Various conditions of reservoirs, including full and empty state, are considered in the analyses. Fluid–structure interaction was completely taken into account. It was realized that incorporating rotational components increased the maximum compressive and tensile stresses in both empty and full reservoir analyses. Distribution of maximum tensile stresses is very sensitive to the rotational components of the earthquake. Also, it can be concluded that the segregated effect of the rocking component on the response of concrete dams is more effective than the sole effect of the torsional component.     

The M 2 ocean tide loading wave in Alaska: vertical and horizontal displacements, modelled and observed

Crustal deformations caused by surface load due to ocean tides are strongly dependent on the surface load closest to the observation site. In order to correctly model this ocean loading effect near irregular coastal areas, a high-resolution coastline is required. A test is carried out using two GPS sites located in Alaska, where the ocean tide loading effect is large and consequently observed easily by relative positioning with GPS. The selected sites are Fair (Fairbanks) and Chi3 (located on an island that separates Prince William Sound from the Gulf of Alaska). Processing of hourly baseline solutions between Fair and Chi3 over a period of 49 days yields a significant ocean tide loading effect. The data are processed using different strategies for the tropospheric delay correction. However, the best results are obtained when 1-h ZTD (Zenith Tropospheric Delay) parameters for hourly solutions are used. In this case ocean tide loading is not absorbed into the ZTD parameters. Hence, ocean tide loading can be well resolved in the GPS data analysis. In addition, the M ₂ ocean tide wave in the Gulf of Alaska has a very large amplitude. Although the horizontal M ₂ ocean tide loading amplitude in general is only about 1/4 of the vertical M ₂ ocean tide loading amplitude, the differential horizontal M ₂ ocean tide loading displacements are nevertheless measurable using differential GPS (DGPS). When using the GOT99.2 ocean tide model and taking the coastal structure into account, the predicted differential vertical M ₂ amplitude and Greenwich phase lag due to ocean tide loading are 19.3 mm and 110.2 degrees respectively, while GPS measurements yield 21.3 ± 1.0 mm and 99.7±2.8 degrees. Similarly, the predicted differential horizontal M ₂ amplitude and Greenwich phase lag (in the north–south direction) are 4.5 mm and –77.0 degrees, while GPS yields 5.4 ± 0.3 mm and –106.3±3.3 degrees. Only the north-south component of the differential horizontal M ₂ ocean tide loading wave is considered, because the east–west component is too small for the processed baseline and not detectable using DGPS.     

Investigations into critical earthquake load models within deterministic and probabilistic frameworks

This paper deals with the determination of critical earthquake load models for linear structures subjected to single‐point seismic inputs. The primary objective of this study is to examine the realism in critical excitations and critical responses vis a vis the framework adopted for the study and constraints that these excitations are taken to satisfy. Two alternative approaches are investigated. In the first approach, the critical earthquake is expressed in terms of a Fourier series that is modulated by an enveloping function that imparts transient nature to the inputs. The Fourier coefficients are taken to be deterministic and are constrained to satisfy specified upper and lower bounds. Estimates on these bounds, for a given site, are obtained by analysing past earthquake records from the same site or similar sites. The unknown Fourier coefficients are determined such that the response of a given structure is maximized subjected to these bounds and additional constraints on intensity, peak ground acceleration, peak ground velocity and peak ground displacement. In the second approach, the critical earthquake is modelled as a partially specified non‐stationary Gaussian random process which is defined in terms of a stationary random process of unknown power spectral density (psd) function modulated by a deterministic envelope function. The input is constrained to possess specified variance and average zero crossing rate. Additionally, a new constraint in terms of entropy rate representing the expected level of disorder in the excitation is also imposed. The unknown psd function of the stationary part of the input is determined so that the response of a given structure is maximized. The optimization problem in both these approaches is solved by using sequential quadratic programming method. The procedures developed are illustrated by considering the seismic response of a tall chimney and an earth dam. It is concluded that the imposition of lower and upper bounds on Fourier coefficients in the first approach and constraints on amount of disorder in the second approach are crucial in arriving at realistic critical excitations. Copyright © 2002 John Wiley & Sons, Ltd.     

Incoming solar radiation measurements in Iraq and their presentation

Summary Measurements of the total incoming solar radiation on a horizontal surface have been recorded since 1967 at a network of actinometric stations in Iraq. The instrument used at each of these stations is a bimetallic actinograph of the Robitzsch type. The stations at Mosul, Baghdad and Nasiriya have been selected, to represent respectively the northern, central and southern climatic zones of Iraq.This paper examines from the available records at these stations, until August 1973, the differnt aspects of radiation climatology which are important in solar energy utilizations. The mean annual, monthly and daily radiation; the number of days in which the radiation has exceeded certain given limits and the periods of successive days having radiation less than 100 and 250 cal cm^–2 day^–1 have been studied and presented in tabular and graphical forms suitable for direct application.To architects and engineers interested in the availability of solar radiation on vertical and inclined surfaces, the hourly radiation values for Baghdad have been studied for the different months of the year and the corresponding isopleths on the horizontal have been drawn.     

Climate change adaptation: a systematic review on domains and indicators

In recent years, climate change has been one of the most complicated problems that human being has faced. Climate change adaptation (CCA) is considered to be an important component of risk management. In order to achieve adaptation, it is necessary to determine the indicators influencing adaptation in each community and this requires measurement and standard tools. The aim of this study is to determine and categorize the indicators of CCA. International electronic databases including Science Direct, Web of Science, Scopus, Google Scholar were investigated for only articles published in English language. In addition, Iranian databases including Irandoc, SID, and Magiran were investigated. There was no limitation on the methods of studies. Furthermore, snowball method was used for finding more articles while the ProQuest database was searched for related dissertations. The published documents from 1990 to November 2017 were gathered in this study. Out of 4439 publications initially search, 152 full texts were investigated. Finally, a total of 45 potentially relevant citations were included for full text review; in addition, fourteen other sources were investigated. Using snowball method, we found 24 other articles that were included in our final result. From the searches, 176 indicators were identified, while seven main domains were mentioned. Since in the articles, domains of adaptation are not in the form of a model, it is better to focus on this issue in the future and it seems that prioritizing and weighting domains in adaptation in different communities with different needs are an important issue.

     

Discussion of ‘A new approach of selecting real input ground motions for seismic design: The most unfavourable real seismic design ground motions’ by C‐H Zhai and L‐L Xie

This discussion consists of two parts. The first part raises a few comments and questions on the method presented in the above paper. The second part proposes a measure for identifying resonant accelerograms in a set of earthquake records without the need for pre‐processing of the records or inclusion of the structure dynamic analysis. Copyright © 2008 John Wiley & Sons, Ltd.     

Temporal changes in the physical properties and chemical composition of the municipal water supply of Shahrood<Emphasis Type="Bold">,</Emphasis> northeastern Iran

A systematic monitoring program was implemented in 1999 to evaluate the temporal changes in the physical properties and chemical composition of water from the Shahrood Qanat, which provides 30% of Shahroods municipal water needs. A qanat is a near-horizontal gallery which yields water by gravity. The results show that the physical properties, in contrast to the concentration of ions, are in an almost steady state condition and the slight variations are due to the travel time of water in the qanat gallery, the mixing of qanat water, the seasonal temperature fluctuation, and the likely unavoidable errors associated with long-term monitoring. They also show that severe drought during the past nine years has not yet affected the groundwater quality. The TDS of the qanat water is relatively low and the water is of the calcium-bicarbonate type. However, the above average concentrations of nitrate (14.9 mg/L) and phosphate (0.105 mg/L) may reflect the impact of the excessive use of fertilizers in the capture zone of the qanat. High Ca, Mg, pH, and a higher-than-recommended hardness value reflect the influence of carbonate-rock formations on the groundwater composition. The study shows that systematic monitoring is required to identify the erroneous data, to optimize the monitoring program and to characterize the water quality trend.

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Resumen En 1999 fue implementado un programa intensivo y sistemático de monitoreo, para evaluar los cambios temporales en las propiedades físicas y en la composición química de la galería para captar agua tipo kanat de Shahrood. Los resultados muestran que las propiedades físicas se encuentran casi en una condición estacionaria y que las poco significativas y tenues variaciones, se deben al tiempo de viaje del agua en la galería kanat, a la mezcla del agua del kanat, a la fluctuación estacional de temperaturas y a los probables e inevitables errores asociados con el monitoreo de largo plazo. Con base en los resultados del presente estudio se determinó que las sequías más severas, ocurridas durante los últimos nueve años, no han afectado aún la calidad del agua subterránea. El contenido de TDS en el agua del kanat es relativamente bajo y el agua es del tipo bicarbonatada-calcica. Sin embargo las concentraciones por encima del promedio de nitratos (14.5 mg/L) y fosfatos (0.105 mg/L), reflejan el impacto del uso excesivo de fertilizantes en la zona de captura del kanat, sobre la calidad del agua subterránea. Los valores altos de Ca, Mg, pH y dureza reflejan la influencia de las formaciones carbonatadas sobre la composición del agua subterránea. El estudio muestra que se necesita un monitoreo sistemático para identificar los datos erróneos, lo mismo que para optimizar el programa de monitoreo y para predecir potenciales cambios futuros en la calidad del agua.

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Résumé A partir de 1999 on a mis au point un programme de surveillance systématique pour évaluer les changements temporelle des propriétés physiques et chimiques de leau du captage de type qanat de Shahrood. Il a résulté que les propriétés physiques sont presque stationnaires, les variations insignifiants ayant dues au temps de transfert et au mélange de leau dans la galerie, aux variations saisonnières de la température ainsi quaux erreurs inévitables associées à une surveillance à long terme. Cet étude a montré aussi que la qualité de leau na pas été influencée par la période de neuf ans de sécheresse. Le résidu à sec de leau présente des variations assez faibles et leau appartient à la catégorie de Calcium-Bicarbonate. Tout de même les valeurs moyennes des concentrations en nitrates (14.5 mg/L) et en phosphates (0.105 mg/L) mettent en évidence limpact de lutilisation excessive des engrains dans les zones de captage de qanat de Shahrood. Les valeurs élevées de la concentrations en Ca et Mg, du pH et le fait que la dureté dépasse les limites recommandées mettent en évidence linfluence des carbonates de la matrice sur la composition des eaux souterraines. Cet étude montre aussi quil est nécessaire une surveillance systématique affin didentifier les données erronées, doptimiser le programme de monitoring et destimer les changements potentielles de la qualité de leau.