The effect of discontinuity frequency on ground vibrations produced from bench blasting: A case study

A good number of empirical formulae and methods dealing with the analysis of the effects of blast-induced ground vibrations have been developed. The most common approach suggested for estimating the attenuation of particle velocity on the ground is to scale the distance (scaled distance, SD). This approach makes it possible to estimate the peak particle velocity when the amount of explosive charge or the distance or both are altered.Many parameters known to have an influence on particle velocity have been used for particle velocity prediction equations. Some of these parameters are maximum charge per delay, the distance between the station and shot location, burden, inelastic attenuation factor and site factors. However, the impacts of the discontinuities existing on the benches where blasts are detonated on the propagation velocity of seismic waves have not been taken into consideration in these equations.This study aims to examine the impacts of the discontinuity frequency parameter derived through geological measurements carried out on the blasting benches or nearby in a quarry mine (Supren, Eskisehir) in Turkey on the propagation of blast-induced ground vibrations. Developed based on the geological observations carried out on the benches, the model was formed by adding discontinuity frequency parameter to the particle velocity prediction model suggested by Nicholls et al. [Nicholls HR, Johnson CF, Duvall WI. Blasting vibrations and their effects on structures. Bulletin no. 656. Washington, DC: US Bureau of Mines; 1971]. In order to research the effect of the discontinuity frequency in the bench on the blast-induced ground vibrations, the relationship between the recorded peak particle velocity, scaled distance and discontinuity frequency was statistically evaluated for the site. The established relationship and the results of the study are presented.     

Investigation of seasonal droughts and related large-scale atmospheric dynamics over the Potwar Plateau of Pakistan

As a result of climate change and unsustainable land use management in the recent past, droughts have become one of the most devastating climatic hazards whose impacts may prolong from months to years. This study presents analysis of droughts for two major cropping seasons, i.e., Kharif (May–September) and Rabi (October–April), over the Potwar Plateau of Pakistan. The analysis is performed using various datasets viz. observational, reanalysis, and Regional Climate Models (RCMs), for the past (1981–2010) and future (2011–2100) time periods. The following two methods for the identification of dry and wet years, also referred to as drought and wetness, are applied: (1) the percentile rank approach and (2) the drought indices, Standardized Precipitation Index (SPI) and Reconnaissance Drought Index (RDI). Future projections of droughts are investigated using RCM (RegCM4.4 and RCA4) outputs from CORDEX South Asia domain under two Representative Concentration Pathway (RCP) scenarios, RCP4.5 and RCP8.5. Generally, the indices show non-significant decreasing trends of drought severity in the recent past for all cases; however, significant increasing trends are observed for annual (0.006) and Kharif (0.007) cases under RCP4.5 scenario. The analysis of large-scale atmospheric dynamics suggests the significant role of low-level geopotential height anomalies over Tibetan Plateau (northwest of Pakistan) during Kharif (Rabi) season in controlling drought occurrence by transporting moisture from the Bay of Bengal (Arabian Sea). Moreover, composites of vertically integrated moisture transport, moisture flux convergence/divergence, and precipitable water anomalies show their marked contribution in maintaining the drought/wetness conditions over the Potwar region.     

Changes in seasonality and timing of peak streamflow in snow and semi‐arid climates of the north‐central United States, 1910–2012

Changes in the seasonality and timing of annual peak streamflow in the north‐central USA are likely because of changes in precipitation and temperature regimes. A source of long‐term information about flood events across the study area is the U.S. Geological Survey peak streamflow database. However, one challenge of answering climate‐related questions with this dataset is that even in snowmelt‐dominated areas, it is a mixed population of snowmelt/spring rain generated peaks and summer/fall rain generated peaks. Therefore, a process was developed to divide the annual peaks into two populations, or seasons, snowmelt/spring, and summer/fall. The two series were then tested for the hypotheses that because of changes in precipitation regimes, the odds of summer/fall peaks have increased and, because of temperature changes, snowmelt/spring peaks happen earlier. Over climatologically and geographically similar regions in the north‐central USA, logistic regression was used to model the odds of getting a summer/fall peak. When controlling for antecedent wet and dry conditions and geographical differences, the odds of summer/fall peaks occurring have increased across the study area. With respect to timing within the seasons, trend analysis showed that in northern portions of the study region, snowmelt/spring peaks are occurring earlier. The timing of snowmelt/spring peaks in three regions in the northern part of the study area is earlier by 8.7– 14.3 days. These changes have implications for water interests, such as potential changes in lead‐time for flood forecasting or changes in the operation of flood‐control dams. Copyright © 2015 John Wiley & Sons, Ltd.     

Improving soil moisture accounting and streamflow prediction in SWAT by incorporating a modified time‐dependent Curve Number method

The objective of this study is to incorporate a time‐dependent Soil Moisture Accounting (SMA) based Curve Number method (SMA_CN) in Soil and Water Assessment Tool (SWAT) and compare its performance with the existing CN method in SWAT by simulating the hydrology of two agricultural watersheds in Indiana, USA. Results show that fusion of the SMA_CN method causes decrease in runoff volume and increase in profile soil moisture content, associated with larger groundwater contribution to the streamflow. In addition, the higher amount of moisture in the soil profile slightly elevates the actual evapotranspiration. The SMA‐based SWAT configuration consistently produces improved goodness‐of‐fit scores and less uncertain outputs with respect to streamflow during both calibration and validation. The SMA_CN method exhibits a better match with the observed data for all flow regimes, thereby addressing issues related to peak and low flow predictions by SWAT in many past studies. Comparison of the calibrated model outputs with field‐scale soil moisture observations reveals that the SMA overhauling enables SWAT to represent soil moisture condition more accurately, with better response to the incident rainfall dynamics. While the results from the modification of the CN method in SWAT are promising, more studies including watersheds with various physical and climatic settings are needed to validate the proposed approach. Copyright © 2015 John Wiley & Sons, Ltd.     

Evaluation of groundwater quality in the Dibdibba aquifer using hydrogeochemical and isotope techniques (Basrah Province,Iraq)

Acta Geochimica - The Dibdibba aquifer is considered to be the main source in the Al-Zubair area because agriculture depends on it to provide grazing water in the area. The groundwater well samples...     

Simultaneous adoption of risk management strategies to manage the catastrophic risk of maize farmers in Bangladesh

GeoJournal - Risk and uncertainty are distinctive features of agricultural cultivation, which significantly affect the production and income. Risk management is an important way for farmers to...     

Coping strategies and struggle against food insecurity: the case of district Banda in Bundelkhand region,India

GeoJournal - Present study examines the current situation of food insecurity in Banda district of Bundelkhand region on the basis of measures of food quality and food quantity. Coping strategy...     

The effects of season on fatty acid composition and ω3/ω6 ratios of northern pike(Esox lucius L.,1758) muscle lipids

In the present study,the effects of season on fatty acid composition,total lipids,and ω3/ω6ratios of northern pike muscle lipids in Kizilirmak River(Kirikkale,Turkey) were investigated.A total of 35 different fatty acids were determined in gas chromatography.Among these,palmitic,oleic,and palmitoleic acids had the highest proportion.The main polyunsaturated fatty acids(PUFAs) were found to be docosahexaenoic acid,eicosapentaenoic acid,and arachidonic acid.There were more PUFAs than monounsaturated fatty acids(MUFA) in all seasons.Similarly,the percentages of ω3 fatty acids were higher than those of total ω6 fatty acids in the fatty acid composition.ω3/ω6 ratios were calculated as 1.53,1.32,1.97,and 1.71 in spring,summer,autumn and winter,respectively.Overall,we found that the fatty acid composition and ω3/ω6 fatty acid ratio in the muscle of northern pike were significantly influenced by season.     

Stakeholder's views on fisheries compliance: An Australian case study

This study presents the results of a field survey that focused on the views of Tasmanian abalone fishery stakeholders (commercial and non-commercial divers, processor, enforcement agency and management) with regards to non-compliance in the abalone fishery. The primary data was collected through 22 face-to-face interviews with stakeholders and the Wilcoxon's signed-rank test was used to determine if significant differences existed between the means of responses from primary and secondary stakeholders. It was found that there is no significant difference in mean responses of primary and secondary stakeholders in regard to the factors that have the potential in influencing the non-compliance in the fishery. The similarity of views between the regulators and resource users on the source and nature of non-compliance in the fishery would form the basis for improved compliance strategies.