Temperature is one of the variables that influence the elasto-plastic behavior and integrity of rock outcrops. Fluctuations in temperature can trigger alteration of some of the mineral properties and impact the brittle-plastic transition. Initiation and propagation of thermally induced tension cracks tend to weaken most rock types. The principal goal of this study was to anticipate impacts of thermal stress-strain cycles on the dynamic response of representative rock units exposed in the Khewra Gorge of the Salt Range Punjab of Pakistan. Ten types of sedimentary rock units were sampled, including marl, dolomite, three types of limestone, and five different sandstones exhibiting varying characteristics in outcrop. Boulder specimens were collected from the field and transported to the laboratory to prepare 50 drill cores that could be subjected to thermal cycling between 50 and 200 °C in increments of 50 °C. Room temperature core samples were tested using an Erudite resonance frequency meter to measure their Q-factors and the resonance frequency (Fr) at an applied loading frequency of 7 KHz with 0.01 V output voltage. Results suggest that thermal cycling tends to reduce the dynamic Young’s modulus (Ed) and Q-factor. Other parameters, such as damping ratio (ξ), specific damping capacity (Ψ), and loss factor (?) appeared to increase with increasing temperature cycles, likely as a result of developing thermally induced tensile fractures. The resultant values of the null hypothesis (t-critical and t-stats) suggests that the null hypothesis can be discarded because there was no observable difference between the measured and expected values for the cores tested. The observations and data emanating from this study might be useful in designing low-level radioactive waste landfills, nuclear waste repositories, and deep underground excavations where the increased temperature could alter the mechanical behavior of the parent rock mass. 相似文献
Soil contamination with cadmium has become major concern all over the world because of its adverse impacts on ecosystem health and agricultural land. Soil amendment with biochar may have varied effects on physical and chemical properties of soil. The objective of the study was to explore the impact of sugarcane filter-cake biochar on physiological performance and growth of lettuce in an aged soil. Four different doses (0, 1.5%, 3%, and 5%) of biochar were used in the soil and conditioned for 1 month. After this, lettuce seedlings were grown in the soil. The results showed that the biochar treatment improved the fresh and dry biomass of leaves and roots as well as plant height while diminished the bioavailability of cadmium from the soil. As compared to control, biochar significantly enhanced the chlorophyll content in lettuce leaves. Due to the biochar amendment, the oxidative stress decreased in lettuce shoots over the control. As compared to control, concentration of cadmium in lettuce significantly decreased after the application of biochar. It was concluded that biochar could mitigate the toxicity of cadmium in lettuce by altering the biochemical and physiological processes in cadmium contaminated soil. 相似文献
In the past few decades, rapid urbanization has occurred in many regions of the Kingdom of Saudi Arabia due to increasing population and urban development. Additionally, the effects of global warming on rainfall characteristics have been observed. This rapid change in urbanization and climate change has cause significant changes in the nature of land surfaces and rainfall patterns, which affect the runoff process and the amount of surface runoff during floods. This study investigated the effect of urbanization and rainfall intensity for Hafr Al-Batin watershed located in Saudi Arabia. For this purpose, a hydrologic model, HEC-HMS, was adopted to simulate the flow of different rainfall intesities and urbanization levels. Simulated results showed that for a 100-year storm, a 24-h duration, and an urbanization level of 80%, the peak flow was 213% higher than the estimated current peak and the runoff volume was 112% higher than the current runoff volume. These results show a strong linear correlation between the level of urbanization and both peak discharge and runoff volume. Furthermore, the results indicate that for short return periods, the peak flow is more sensitive to the level of urbanization compared to long periods. 相似文献
The project area lies in the southern part of the Hazara Kashmir syntaxis. The Hazara Kashmir syntaxis is an antiformal structure. The project area includes Rumbli, Namb, Chatrora, Chachan, Panjar, Barathian and Utrinna areas of Rawalpindi and Sudhnoti districts. The southeastern limb of the Hazara Kashmir syntaxis is imbricated along Punjal thrust, Main Boundary thrust and Riasi fault. The Jhelum fault truncates the western limb of Hazara Kashmir syntaxis. The core of syntaxis comprises of Himalayan molasse deposits. These molasse deposits represent the part of cover sequence of Indian plate. These Himalayan molasse deposits include the Early to Middle Miocene Kamlial Formation, Middle to Late Miocene Chinji Formation, Late Miocene Nagri Formation and Late Miocene Dhok Pathan Formation. The area is highly deformed resulting folds and faults. The major folds in the project area are the Panjar anticline, Barathian syncline, Barathian anticline, Rumbli anticline, Chatrora antiformal syncline and Namb syncline. The folds are either northwest-southeast trending or southwestnortheast trending. The folds are asymmetric, open, and gentle and close in nature. The folds are southwest, northeast or southeast vergent. The Jhelum fault truncates the northeast and northwest trending structures. The folds and faults are the result of northeastsouthwest or northwest-southeast Himalayan compression. 相似文献
Mineralogy and Petrology - Rift related magmatism during Permian time in the northern margin of Indian plate is represented by basic dykes in several Himalayan terranes including north western... 相似文献
Tropical cyclones and their devastating impacts are of great concern to coastal communities globally. An appropriate approach integrating climate change scenarios at local scales is essential for producing detailed risk models to support cyclone mitigation measures. This study developed a simple cyclone risk-modelling approach under present and future climate change scenarios using geospatial techniques at local scales, and tested using a case study in Sarankhola Upazila from coastal Bangladesh. Linear storm-surge models were developed up to 100-year return periods. A local sea level rise scenario of 0.34?m for the year 2050 was integrated with surge models to assess the climate change impact. The resultant storm-surge models were used in the risk-modelling procedures. The developed risk models successfully identified the spatial extent and levels of risk that match with actual extent and levels within an acceptable limit of deviation. The result showed that cyclone risk areas increased with the increase of return period. The study also revealed that climate change scenario intensified the cyclone risk area by 5–10% in every return period. The findings indicate this approach has the potential to model cyclone risk in other similar coastal environments for developing mitigation plans and strategies. 相似文献
Based on the survey data of 250 farmers from the Multan district of Southern region of Punjab, Pakistan this study aims to empirically examine the determinants of access to agricultural credit. This study used the probit model to analyze the data. The results revealed that formal education, farm size, level of farm mechanization, farm revenue and landholding size positively and significantly influenced access to agricultural credit while the age of the farmer’s, distance, and off- farm income negatively and insignificantly influenced farmer’s accessibility to agricultural credit. The findings of the current study offer a policy guideline to streamline national policy on agricultural finance. This study also recommends that ZaraiTaraqiati Bank (ZTBL) and other Commercial Banks should improve their agricultural credit schemes to fulfil the diversified needs of small farm holders.
A strong need exists to increase the knowledge and recognize the values of neighborhood services. This paper makes an attempt to examine the impact of neighborhood services on land values, through analysis based on results obtained from multi linear regression analysis. This case study was done in area of dense urban settlement to check the consequence of neighborhood services through the hedonic pricing model base variables which include the structural, locational, community and neighborhood services. The regression coefficient was checked at (p?<?0.05) level of significance for each variable. The primary data was collect through the questionnaire filling by random sampling and Punjab Urban Gazette was used for the verification of land values in study area. The results found a valuable potential on land and property values of neighborhood services through the regression analysis results express through R (0.926), R2 (0.856) and coefficient tables to represent the effect of each individual variable on property and land values. Every individual variable play role in defining the values of land and property based upon its utilization such as larger the structure of a property, more the covered area, larger size of a property more the land area higher price. Similarly, for locational factor study in geography, a piece of land adjacent to the road have high land values 50–70% compare to those located at distance. Very less attention has been paid on such issues in the world due to lack of effective urban planning and research on such crucial issues. If empirical studies on such issue has been done, effective way can be obtained for urban planning.
Natural Hazards - The Karakoram Highway links north Pakistan with southwest China. It passes through unique geomorphological, geological and tectonic setting. This study focused 200-km-long section... 相似文献
Geotechnical and Geological Engineering - Shallow and deep seated landslides in natural slopes are often induced by rainfall. The cause of the failure is usually considered to be due to the... 相似文献
