Salt Gradient

A numerical investigation on the non-convective salt-gradient solar pond was carried out to study the effect of different variables on the solar pond performance. A numerical computer program was performed to show the relations between the different pond variables. The investigation analysis was performed at selected days (1, 15, and 20 th ) of December 2012 at Jordan-Amman climate. The results of investigation show that the temperature of storage zone will increase by decreasing the depth of both UCZ and LCZ and increasing the depth of NCZ.

Clean energy is needed to sustainably power our economies and communities. Salt gradients, which are available in marine ecosystems as well as from the brine of engineered desalination systems, are a renewable source of energy. Membrane-based osmotic power processes have been proposed for converting the free energy of mixing seawater and diluted water to useful mechanical work. It has been shown that during osmosis, the applied mechanical load as well as the circulation rates of diluted feed and concentrated draw through the membrane module have a significant impact of transport dynamics, including polarization and friction. Therefore, to maximize performance of this process, it is necessary to carefully adjust these operating conditions. Using modelling and simulation, our group has previously shown that it is possible to coordinate the control of these key operating variables in order to maximize net power output. In this work, we report on our efforts to experimentally demonstrate the concept of real-time maximum power point tracking for a salt gradient osmotic power system. The transient response of a laboratory scale osmotic system is characterized, showing water permeate flux, pressure losses, and power output in response to step changes in applied pressure and to feed and draw circulation rates. A “perturb and observe” feedback algorithm and control strategy are implemented and as a result, the real-time net power output of the osmotic power system is shown to more than double relative to baseline conditions. Such real-time control strategies have broad applications to a variety of membrane processes and can be customized to track selected performance metrics.

Solar pond technology is being used in this world for the past many years, yet this technology has to prove its effectiveness in energy starved country like Pakistan and resolve energy crisis of the country. This research discusses basic principles of solar pond design, construction of a prototype solar pond, thermal energy extraction from the solar pond and cost benefit analysis of this technology for industrial sector in Pakistan in the form of a case study.

Cation exchange chromatography (CEX) of therapeutic monoclonal antibodies is generally performed with either salt gradient (MES buffer + NaCl) or using commercial pH gradient buffer. The goal of this study was to find out some alternative buffer systems for CEX separation of mAbs, which may offer alternative selectivity, while maintaining similar peak shapes. Among the new buffers that were tested, (N-morpholino)ethanesulfonic acid (MES) / 1,3-diamino-2-propanol (DAP), and citric acid / 2-(cyclohexylamino)ethanesulfonic acid (CHES) systems were particularly promising, especially when combining them with a moderate salt gradient of NaCl. This two buffer system provides an equivalent or slightly better separation than the standard, mobile phases for therapeutic mAbs. It was also demonstrated that working with salt-mediated pH gradients, allows to extend the possibilities in method development, since the concentration of salt in the mobile phase has a significant impact on selectivity. Using HPLC modeling software (Drylab), it was possible to successfully develop CEX methods for authentic mAb samples within only 6 h, by optimizing the gradient steepness and salt concentration in the B eluent.

Cation exchange chromatography (CEX) of therapeutic monoclonal antibodies is generally performed with either salt gradient (MES buffer + NaCl) or using commercial pH gradient buffer. The goal of this study was to find out some alternative buffer systems for CEX separation of mAbs, which may offer alternative selectivity, while maintaining similar peak shapes. Among the new buffers that were tested, (N-morpholino)ethanesulfonic acid (MES) / 1,3-diamino-2-propanol (DAP), and citric acid / 2-(cyclohexylamino)ethanesulfonic acid (CHES) systems were particularly promising, especially when combining them with a moderate salt gradient of NaCl. This two buffer system provides an equivalent or slightly better separation than the standard, mobile phases for therapeutic mAbs. It was also demonstrated that working with salt-mediated pH gradients, allows to extend the possibilities in method development, since the concentration of salt in the mobile phase has a significant impact on selectivity. Using HPLC modeling software (Drylab), it was possible to successfully develop CEX methods for authentic mAb samples within only 6 h, by optimizing the gradient steepness and salt concentration in the B eluent.

A numerical investigation on the non-convective salt-gradient solar pond was carried out to study the effect of different variables on the solar pond performance. A numerical computer program was performed to show the relations between the different pond variables. The investigation analysis was performed at selected days (1, 15, and 20 th) of December 2012 at Jordan-Amman climate. The results of investigation show that the temperature of storage zone will increase by decreasing the depth of both UCZ and LCZ and increasing the depth of NCZ.

Solar pond is one of the most economical and easily constructed device for harvesting solar radiation to meet the present crisis of energy hungry world solar energy is the only means to satisfy the present need. Numbers of method are available to harness the solar energy; solar pond is one of such method. However at present the limited use of solar pond is due to low temperature availability of stored energy, much more efforts and experimentation are needed to find out various alternate solutions for making solar pond more efficient and usable. Since large pond requires much more expenses and up keeping. A portable solar pond can be easily made and can be rigged up to conduct various experiments to find out the best answer for some of the performance parameter for solar pond.This paper deals with design, construction and application of a portable laboratory model of solar pond. The model can be used for various experiments in the laboratory and conduct research work.

Abstraet--A small-scale salt-gradient solar pond having 2 × 2 m aperture area and 0.5 m depth was constructed on the roof of the heat laboratory at Assiut University. It was covered with transparent polyethylene sheet. An in-pond heat exchanger was used. The tests were started in July 1986. A planar reflector was attached to the pond to improve its performance. Measurements have been carried out for vertical temperature and salinity distributions. The pond performance was evaluated by a collection efficiency based on the overall energy balance of the pond. The effects of the planar reflector tilt angle, reflection characteristics of the pond's inside walls on the pond efficiency were studied. Linear correlations similar to that of a flat plate collector were obtained for both instantaneous and average pond collection efficiencies.