Auditory memory function in expert chess players

Background: Chess is a game that involves many aspects of high level cognition such as memory, attention, focus and problem solving. Long term practice of chess can improve cognition performances and behavioral skills. Auditory memory, as a kind of memory, can be influenced by strengthening processes following long term chess playing like other behavioral skills because of common processing pathways in the brain. The purpose of this study was to evaluate the auditory memory function of expert chess players using the Persian version of dichotic auditory-verbal memory test. Methods: The Persian version of dichotic auditory-verbal memory test was performed for 30 expert chess players aged 20-35 years and 30 non chess players who were matched by different conditions; the participants in both groups were randomly selected. The performance of the two groups was compared by independent samples t-test using SPSS version 21. Results: The mean score of dichotic auditory-verbal memory test between the two groups, expert chess players and non-chess players, revealed a significant difference (p = 0.001). The difference between the ears scores for expert chess players (p = 0.023) and non-chess players (p = 0.013) was significant. Gender had no effect on the test results. Conclusion: Auditory memory function in expert chess players was significantly better compared to non-chess players. It seems that increased auditory memory function is related to strengthening cognitive performances due to playing chess for a long time

Mechanical Properties of Brick Vault and Adobe Piers - A Heritage Case Study

Many un-reinforced masonry heritage structures are widely present throughout Iran and around the world. These structures seem to suffer the most sever damage during earthquakes. Not only the prohibitive cost of replacing all substandard structures, but also the conservation of these buildings, necessitates the development of innovative techniques for rehabilitating deteriorating structures. Masonry is a complex material which exhibits distinct directional properties due to the mortar joints which act as planes of weakness. For numerical modelling a masonry structure, macro-models and micro-models can be used. In order to evaluate the material description for macro modelling, tests should be performed in masonry prisms with sufficient size under homogeneous states of stress and strain. This paper reports the mechanical property of the brick vault and adobe piers of a heritage complex building located in Yard city, Iran with clay and clay and gypsum-mortars respectively that are determined by testing prism specimens. Standard testing machines and two points bending test are employed to evaluate the mechanical properties of brick vault, adobe piers, units and mortars. Finally, nonlinear macro-modelling analyses are carried out in order to calibrate the tests results. Good correlation between numerical and tests results is observed

Performance based assessment for FRP-retrofitted existing RC frames

In recent years, performance based design has become universally acceptable in seismic assessment of structures. Using this design method, performance of existing and retrofitted RC buildings can be evaluated based on the criteria suggested by ATC-40 and FEMA-356 using nonlinear pushover analysis. In this paper, performance of an FRP-retrofitted RC frame is assessed and the result is compared with steel-braced frames and unstrengthened moment resisting frames. The strong-column weak-beam principal is employed in this study. Firstly, the flexural stiffness of FRP-retrofitted joints of an existing RC ordinary moment resisting frame is determined using nonlinear finite element analysis. It is then implemented into a mathematical model for the web-bonded FRP-retrofitted frame developed by the first two authors. Subsequently, the base frame and retrofitted frames (both steel-braced and FRP-retrofitted) are ana-lysed using nonlinear pushover analysis method. Finally, the seismic performance of the FRP-retrofitted frame is compared with the corresponding base frame and steel-braced frames reported by others. The results show that the improvement in ductility and performance level of the existing RC frames is better for frames retrofitted with FRPs than the steel-braced systems

Acid Sulphate Soil Interaction with Groundwater: A Remediation Case Study in East Trinity

AbstractContaminated soil and groundwater resulting from pyrite oxidation occur in coastal areas throughout the world, but do not pose an issue unless allowed to oxidise as a result of drainage or excavation. The exposure and oxidisation of these soils increase the concentration of iron and aluminium ions and cause adverse impact on flora and fauna and also water quality. Depending on the climate conditions and scale of areas contaminated by acid sulphate soil (ASS), several remediation techniques (e.g. fixed-level weirs, two-way modified floodgates, permeable reactive barriers, etc.) can be employed to increase the pH near to neutral and prevent the oxidation of pyrite and production of extra acid.A case study of the East Trinity, the east of Cairns, Queensland, Australia is presented in this study. This region episodically discharges large amounts of acid resulting in periodic fish kills. To remediate the ASS issue, a lime-assisted tidal exchange strategy had been undertaken by the local government. As a result, the quality of water improved and the pH increased from 3.5 to 6-8 and also the rate of aluminium and iron reduced to neutral values

Numerical modeling of CFRP-retrofitted RC exterior beam column joints under cyclic loads

This paper presents the results of a study on the capability of nonlinear quasi-static finite element modelling in simulating the hysteretic behaviour of CFRP-retrofitted RC exterior beam-column joints under cyclic loads. In this study, several unstrengthened and CFRP-strengthened specimens tested by the first and third authors at the University of Queensland, Australia are modelled using ANSYS. Concrete in compression is defined by the modified Hognestead model and anisotropic multi-linear model is employed for modelling the stress-strain relations in reinforcing bars while anisotropic plasticity is considered for the FRP composite. Both concrete and FRP are modelled using solid elements whereas space link elements are used for steel bars. Perfect bond between materials is assumed in this modelling as no considerable de-bonding occurred in the experiments. The specimens are then loaded using a step by step load increment procedure to simulate the cyclic loading regime employed in testing. In this analysis procedure, an automatically reforming stiffness matrix strategy is used in order to simulate the actual seismic performance of the RC concrete after cracking, steel yielding and concrete crashing during the push and pull loading cycles. The results show that the hysteresis simulation for both unstrengthened and FRP-strengthened specimens is satisfactory and therefore suggest that the numerical model can be used as an inexpensive tool in the design of FRP reinforcement levels to improve the hysteretic performance of RC beam-column joints under cyclic loads

A Short State-of-the-Art Review on Construction and Settlement of Soft Clay Soil Reinforced with Stone Column

The primary application of various geotechnical construction techniques is for ground improvement. Many soil improvement methods have been developed due to the ongoing increase in urban and industrial growth and the need for greater access to lands. Stone columns are one of the best available techniques for soft clay soil improvement. In this method, subsurface soils which are weak and unstable are replaced with compacted dense aggregate columns that often entirely penetrate into the weak layers. This paper aims to present a short state-of-the art on the stone column ground improvement technique based on existing literature and standards. Due to high permeability of the material component used in the stone columns, not only the load carrying capacity of the soil is raised, but also the soil settlement is reduced considerably and the post construction settlement is minimized. To achieve this goal, several significant characteristics of stone column in terms of design parameters are considered. One example of the behavior assessment of reinforced soil using stone column is included. A new one-dimensional analysis has been studied in addition to a simplified nonlinear finite element method. The results indicate that the new method is reliable. It is also indicated that the settlement of the soil without stone columns is significantly higher than the similar soil reinforced with stone column

Seismic Rehabilitation of Historical Masonry Vaults using FRPs - A Case Study

Collapse of non-engineered historical buildings in seismically active regions of Iran has been reported widely. Masonry dome and vault, which were built by adobe or bricks with clay, lime/clay or chalk/clay mortar have often been used in these buildings m cover the roof. Conservation of historical heritage may become necessary in order to improve their seismic resistance. In this paper, potential failure of a heritage brick vault located in Yazd city, Iran built in 1935 is investigated under lateral loads. In this building, the piers were built by adobe masonry whereas the roof vault was made up of clay bricks with chalk/clay mortar. A nonlinear finite element model is used in the investigation in which the masonry is modelled as an anisotropic continuum using smeared material models. The material properties of continuum masonry are determined by testing. Finally, the brick vault is strengthened using CFRP sheets at extrados with different architecture and the failure mechanisms of the structure before and after strengthening are compared. Results show that when the vault is strengthened at extrados, the failure mechanism would improve to provide higher ultimate load capacities