Sharif Digital Repository

Structural and dynamic properties of ions confined in nanoslits are crucial to understand the fundamental mechanism underlying a wide range of chemical and biological phenomena. K + and Cl - show similar ion mobilities in a bulk aqueous solution, whereas they exhibit a remarkable difference when transporting through an angstrom-scale channel. Our molecular dynamics simulations uncover that such discrepancy originates from the subtle differences in their hydration structures and preferable locations across the channel. Opposite charge causes different water dipolar orientations around ions, mediating the distance and tribological interactions between hydrated ions and channel's walls.... 

Microbial fuel cells (MFCs) have been a potential green energy source for a long time but one of the problems is that either the technology must be used on a large scale or special equipment have been necessary to keep the fuel cells running such as syringe pumps. Paper-based microbial fuel cells do not need to have a syringe pump to run and can run entirely by themselves when placed in contact with the fluids that are necessary for it to run. Paper-based microbial fuel cells are also more compact than traditional MFCs since the device doesn't need any external equipment to run. The goal of this paper is to develop a microbial fuel cell that does not require a syringe pump to function. This... 

The application of silicon nanowire (SiNW) biosensor as a subtle, label-free, and electrical tool has been extensively demonstrated by several researchers over the past few decades. Human ability to delicately fabricate and control its chemical configuration, morphology, and arrangement either separately or in combination with other materials as lead to the development of a nanomaterial with specific and efficient electronic and catalytic properties useful in the fields of biological sciences and renewable energy. This review illuminates on the various synthetic methods of SiNW, with its optical and electrical properties that make them one of the most applicable nanomaterials in the field of... 

Effective and rapid mixing is crucial for chemical and biological processes. The purpose of the current study is to investigate the effect of steady and varying magnetic field on the mixing of a water-based ferrofluid and two streams of deionized water inside a microchannel for Lab-on-Chip applications. To this end, the nonlinear governing equations, the momentum equation, the continuity equation, the mass transport equation and the Maxwell-Ampere equations are numerically solved. A commercial code based on the finite-element method is used and the numerical simulations are validated by the experimental results in the literature. To augment the mixing performance, the effects of influencing... 

Water treatment is a process used to eliminate or reduce chemical and biological contaminants that are potentially harmful to the water supply for human use. Stimuli-responsive polymers are a new category of smart materials used in water treatment via a stimuli-induced purification process and subsequent regeneration of the polymers. Stimuli-responsive polymers dynamically change their physico-chemical properties upon environmental changes. They can undergo shrinkage or expansion, alter their optical properties, and change their electrical characteristics depending on the applied stimuli. In this context, various stimuli-responsive polymer systems such as self-assembled nanostructures,... 

The present study investigates the diversification and dynamic behavior of a multi-population microfluidic microbial fuel cell (MFC) as a biosensor. The cost effective microfluidic MFC coupled to a comprehensive model, presents a novel platform for monitoring chemical and biological phenomena. The importance of competition among different microbial groups, hierarchical biochemical processes, bacterial chemotaxis and different mechanisms of electron transfer were significant considerations in the present model. The validation of the model using experimental data from a microfluidic MFC shows an appropriate match with the hierarchal biodegradation processes of a complex substrate as well as...