Effect of compaction pressure on consolidation behaviour of unsaturated silty soil

The effect of compaction pressure on subsequent soil behaviour during isotropic consolidation has been investigated by conducting controlled-suction triaxial tests on samples of an unsaturated compacted silty soil. A comprehensive set of laboratory experiments was carried out in a double-walled triaxial apparatus on samples of unsaturated soil that were prepared using two different compaction pressures. The axis translation technique was used for creating the desired suctions in the samples. In the experiments, the soil samples were subjected to isotropic consolidation under constant suctions. The results show that different compaction pressures produce different fabrics in a soil and therefore affect the behaviour of the soil. The results also show that the value of yield stress and the location of the loading¿collapse (LC) yield curve are functions of soil fabric. Furthermore, it is shown that the slopes of normal consolidation lines for densely and loosely compacted samples differ in unsaturated conditions but are the same in saturated soils. A comparison is made between the behaviour of the dense and loose samples, and the difference in the behaviour is explained

Cost-Effective Management of Sea Water Intrusion in Shallow Unconfined Aquifers

The cost efficiency aspects of different hydraulic barriers to control seawater intrusion (SWI) in shallow unconfined aquifer are investigated using the direct integration of simulation model with multi objective optimization tool. Positive barrier by recharging the water into aquifer using subsurface pond, negative barrier by abstraction of saline water and combination of these two are the three scenarios that are optimally assessed in this study. In the descriptive case study considered, the results indicate that application of treated waste water (TWW) as source of recharge increases the efficiency and the practical value of combined management scenario to control SWI

Numerical modelling of the impacts of sea level rise on seawater intrusion in unconfined coastal aquifers

Copyright © 2014 the University of Exeter.This study presents the application of a density-dependent finite element model to simulate the transient effects of sea level rise (SLR) on seawater intrusion (SWI) in a conceptual case of unconfined aquifer. The model considers both the unsaturated and saturated flow conditions. To model the natural process of SLR, a time-dependent boundary condition is used to define the hydrostatic head imposed by seawater at the coastal boundary where the effect of the gradual rise in the sea level with time is considered. The specified values of SLR are chosen, in the range of that predicted by IPCC (Intergovernmental Panel on Climate Change), for five different periods of time in the current century (from 2014 to 2100). The results indicate that a considerable advance in SWI can be expected in the coastal aquifers until the end of century. The rising of sea level is followed by the lifting of the groundwater table, especially near the shoreline, which gradually declines towards the inland boundary. The effects of spatial variations of the shoreline slope on SWI under SLR condition are also investigated. The results highlight that the flatter slopes of the shoreline intensify the landward process of seawater intrusion

Evaluation of depression and anxiety in patients with thalassemia: a comparative study

Background: More studies in the field of thalassemia patients focus on medical treatment and less attention to the psychosocial problems aspect. Objective: The aim of this study was evaluation of depression and anxiety in these patients in Qazvin province. Methods: This case-control study has been conducted in Qods Hospital of Qazvin (2016). The study population included thalassemia major patients and control group were participating in this study (n=147 in each group). All subjects completed the hospital anxiety and depression scale (HADS). In addition to clinical history, socioeconomic and demographic characteristics of patients collected and analyzed using proper statistical methods independent t-test, chi-square test. Findings: Borderline abnormal (borderline case) and abnormal states of anxiety were reported 27.2% and 42.2% in case group compared with 22.4% and 6.8% in the control group (P<0.001). In addition, borderline and abnormal states of depression were significantly different in the case group than the control group (respectively 20.4% and 59.2% vs 24.5% and 12.9%, P<0.001). Among patients with thalassemia, depression and anxiety scores significantly were associated with noncompliance and iron chelation, marital status (single) and socioeconomic state (P<0.001). In addition, Moreover, in terms of depression individuals with diabetes, headaches and skin disorders significantly were higher scores of depression and in terms of anxiety individuals with low back pain, headaches and skin disorders were higher scores. Conclusion: The prevalence of depression and anxiety in patients with thalassemia is considerable and related to socioeconomic and demographic characteristics, so it is essential that psychiatric consultation systems created in thalassemia clinics of Qazvin province

Experimental Study of the Mechanical Behavior of Frozen Soils - A Case Study of Tabriz Subway

The mechanical properties of frozen ground are key parameters in design and implementation of artificial ground freezing (AGF) in underground projects. Soil samples were obtained from the urban underground railway project site in Tabriz, Iran. The specimens were classified as SP and CL according to the USCS. The specimens were remolded in accordance with the site conditions. Over 120 triaxial compression tests were conducted on the frozen samples at different temperatures, confining pressures and strain rates. The results show that the frozen SP and CL soils exhibit strain-softening and strain-hardening behaviour, respectively. In all cases, Young’s modulus increases with decreasing temperature and increasing strain rate and confining pressure. Also, the shear strength increases with decreasing temperature and increasing strain rate. In all tests, the Young’s modulus and shear strength of the SP soil are greater than the CL soil. Based on the results of this research, the application of artificial ground freezing was recommended for coarse-grained and non-cohesive soils like SP in the Tabriz underground railway project.&nbsp

Optimal control of seawater intrusion in coastal aquifers

Seawater intrusion is one of the most serious environmental problems in many coastal regions all over the world. This is because mixing a small quantity of seawater with groundwater makes it unsuitable for use and can result in abandonment of aquifers. Therefore, seawater intrusion should be prevented or at least controlled to protect groundwater resources. This paper presents a new method for optimal control of seawater intrusion. The proposed method is based on a combination of abstraction of saline water near shoreline and recharge of aquifer using surface ponds. The source of water for the surface pond could be treated waste water or excess of desalinated brackish water (if any), etc. The variable density flow and solute transport model, SUTRA, is integrated with a Genetic Algorithm optimization tool in order to investigate the efficacy of different scenarios of the seawater intrusion control in an unconfined costal aquifer. The locations of the pond and the abstraction well in relation to the shoreline, depth of abstraction well and the rates of abstraction and recharge are considered as the main decision variables of the optimization model, which aims to minimize the costs of construction and operation of the abstraction wells and recharge ponds as well as the salt concentrations in the aquifer. Comparison is made between the results of the proposed method and other methods of seawater intrusion control. The results indicate that the proposed method is efficient in controlling seawater intrusion. This proposed strategy can be considered as a powerful tool for cost-effective management of seawater intrusion in coastal aquifers

Micropropagation of Grape Cultivars (Vitis vinifera L.) on Different Basal Media Supplemented with Benzyl Adenine

In vitro propagation is a commercial technique that is used for plant propagation around the world. Therefore, the development of in vitro techniques is a sure way for rapid propagation of many plant species. In this study, effect of Woody Plant Medium (WPM) and Murashighe and Skoog (MS) media supplemented with 0.0, 2.2, 4.4, 6.6 and 8.8 μM benzyladenine (BA) on regeneration of three grape cultivars (\u27Bidaneh Sefi d’, ‘Farkhi’ and ‘Khoshnav’) were investigated. In proliferation stage, length of shoots, number of shoots, number of leaves and the final status of explants were evaluated. In rooting stage, effect of indole-3-butyric acid (IBA) in three concentrations (0.0, 0.5 and 1.0 μM) on root initiation, number of rooted explants, root length and number of roots were evaluated. The results showed that the longest shoots were obtained in MS medium supplemented with 2.2 μM BA in the three cultivars, while most adequate shoots were observed in MS medium containing 4.4 μM BA in all studied cultivars. In rooting stage, the best results were obtained by 0.5 μM IBA. The results of this study showed that grape regeneration potential in vitro conditions depend to cultivar, culture medium and concentration of growth regulators