Comparison between pressure retarded osmosis model using batch and continuous water supply sources

Pressure retarded osmosis (PRO) is a novel renewable energy technology that generates electricity from two water sources. Due to the osmotic pressure difference, freshwater permeates across a membrane to the other side, where the high-pressure seawater flows and drives a turbine to generate power. Many mathematic models have been proposed to evaluate the performance of a PRO. However, it was found that most performance of the PRO that have been reported were performance by using freshwater with limited supply (batch) in the model. It is not accurate as, in practice, the supply of freshwater occurs in a continuous manner. In this work, the influence of batch and continuous supply of fresh water on the performance of PRO was demonstrated. The effect of flow direction, i.e., concurrent and counter-current flows, was also examined. The model simulation was performed by using MATLLAB program, and the performance of PRO is expressed in terms of average power density. The results revealed that the batch and continuous supplies of freshwater had a strong impact on the performance of the PRO. However, the performance of concurrent and counter-current flow were not significantly different.

Nanofluidic osmotic power generators – advanced nanoporous membranes and nanochannels for blue energy harvesting

Advanced nanostructured membranes with high ion flux and selectivity bring new opportunities for generating clean energy by exploiting the osmotic pressure difference between water sources of different salinities.

Membrane Transport in Concentration Polarization Conditions: Evaluation of S-Entropy Production for Ternary Non-Electrolyte Solutions

A model of the S-entropy production in a system with a membrane which separates non-electrolyte aqueous solutions was presented. The differences between fluxes in non-homogeneous and homogeneous conditions for volume and solute fluxes, respectively, are non-linear functions of the glucose osmotic pressure difference (OPD) in ranges dependent on the initial ethanol OPD. A decrease of ethanol OPD causes a shift of this range into the lower values of glucose OPD; this shift is also observed for negative values of glucose and ethanol OPDs. The coefficient of concentration polarization of the membrane as a function of glucose OPD has a sigmoidal shape. For suitably great negative values of glucose OPD this coefficient is very small, while for suitably high positive glucose OPD this coefficient is equal to 0.5. An increase of ethanol OPD at the initial moment causes a shift of this curve towards the direction of positive values of glucose OPD. In turn the S-entropy production in non-homogeneous conditions has low values for negative values of glucose OPD (convective range) while for suitably high positive glucose OPD it has greater values (diffusive and convective range). A change of ethanol OPD at the initial moment causes a shift of this curve along the horizontal axis.

On Multicellular Lipid Compartments and Their Electrical Activity

<p>In this manuscript, we report our ground-breaking result on development of artificial multicellular structures capable for neuron like spiking activity. These structures are self-growing ensembles of vesicles whose membranes are combinations of phospholipid and viscous amphipathic molecules. The vesicles grow from a porous gel, and an osmotic pressure difference between the interior of the gel and its surrounding drives the growth. The vesicles’ membranes have also incorporated pore forming proteins. The growing ensembles exhibit spike-like dynamics in electrical potential recorded on the electrodes inserted in the ensembles. We speculate that the spike-like electrical activity is due to the breaking and leaking of the compartments, fusion, and fission of the vesicles during the growth. We demonstrate the spontaneous growth of multi-cellular lipid compartments, which can also incorporate liposomes with membrane proteins, and their generation of an electrical spike-like signal. The bottom-up development of a multicellular artificial molecular system like this report would lead the transition of material's complexity toward information transfer emulating that of a nervous system.</p><p> </p><p>The evidence of neuromorphic electrical activity in multicellular systems of lipid vesicles is a promising indication of feasibility of future designs of self-growing artificial proto-brains. We, therefore, think that this manuscript should attract outstanding interest from the wide community of scientists, engineers and laymen, especially those interested in in artificial life, molecular computing, origins of life, artificial cell, molecular robotics, and synthetic biology.</p>

On Multicellular Lipid Compartments and Their Electrical Activity

<p>In this manuscript, we report our ground-breaking result on development of artificial multicellular structures capable for neuron like spiking activity. These structures are self-growing ensembles of vesicles whose membranes are combinations of phospholipid and viscous amphipathic molecules. The vesicles grow from a porous gel, and an osmotic pressure difference between the interior of the gel and its surrounding drives the growth. The vesicles’ membranes have also incorporated pore forming proteins. The growing ensembles exhibit spike-like dynamics in electrical potential recorded on the electrodes inserted in the ensembles. We speculate that the spike-like electrical activity is due to the breaking and leaking of the compartments, fusion, and fission of the vesicles during the growth. We demonstrate the spontaneous growth of multi-cellular lipid compartments, which can also incorporate liposomes with membrane proteins, and their generation of an electrical spike-like signal. The bottom-up development of a multicellular artificial molecular system like this report would lead the transition of material's complexity toward information transfer emulating that of a nervous system.</p><p> </p><p>The evidence of neuromorphic electrical activity in multicellular systems of lipid vesicles is a promising indication of feasibility of future designs of self-growing artificial proto-brains. We, therefore, think that this manuscript should attract outstanding interest from the wide community of scientists, engineers and laymen, especially those interested in in artificial life, molecular computing, origins of life, artificial cell, molecular robotics, and synthetic biology.</p>

Membranes: A Variety of Energy Landscapes for Many Transfer Opportunities

A membrane can be represented by an energy landscape that solutes or colloids must cross. A model accounting for the momentum and the mass balances on the membrane energy landscape establishes a new way of writing for the Darcy law. The counter pressure in the Darcy law is no longer written as the result of an osmotic pressure difference but rather as a function of colloid-membrane interactions. The ability of the model to describe the physics of the filtration is discussed in detail. This model is solved on a simplified energy landscape to derive analytical relationships that describe the selectivity and the counter pressure from ab-initio operating conditions. The model shows that the stiffness of the energy landscape has an impact on the process efficiency: a gradual increase in interactions (like with hourglass pore shape) can reduce the separation energetic cost. It allows the introduction of a new paradigm to increase membrane efficiency: the accumulation that is inherent to the separation must be distributed across the membrane. Asymmetric interactions thus lead to direction-dependent transfer properties and the membrane exhibits diode behavior. These new transfer opportunities are discussed.