Real Time Flow Control System for Precise Gas Feed in COIL

This paper reports development of a real time flow control system for precise, controlled and uniform gas feed to a flowing medium Chemical Oxygen Iodine Laser (COIL). The optimal operation of this prominent laser depends upon the desired supply of gas constituents such as nitrogen (N2), chlorine (Cl2) and iodine (I2) to achieve adequately mixed laser gas. The laser also demands real time variation of flow rates during gas constituent transitions in order to maintain stabilized pressures in critical subsystems. Diluent nitrogen utilized for singlet oxygen transport is termed as primary buffer gas and that for iodine transport is termed as secondary buffer gas (with main and bypass components). Also, nitrogen in precise flows is used for mirror blowing, nozzle curtain, cavity bleed and diffuser startup. A compact hybrid data acquisition system (Hybrid DAS) for precise flow control using LabVIEW 2014 platform has been developed. The supported flow ranges may vary from few mmole.s-1 to few hundred mmole.s-1. The estimated relative uncertainty in the largest gas component i.e. primary buffer gas feed is nearly 0.7%. The implementation of in-operation variation using flow ramp enables swift stabilization of singlet oxygen generator pressures critical for successful COIL operation. The performance of Hybrid DAS is at par with fully wired DAS providing the crucial benefit of remote field operation at distances of nearly 80m in line of sight and 35m with obstacles

Mathematical model for predicting oxygen concentration in tilapia fish farms

The main aim of this research is to develop a mathematical model to predict the dissolved oxygen in recirculating aquaculture system. The oxygen consumption of the model through the fish respiration and nitrification and the oxygen addition of the model through oxygen generator and water pumping. The effect of different water temperatures (24, 26, 28, 30 and 32 °C) on the dissolved oxygen consumption through fish respiration, biofilter and nitrification and fish growth were studied. An experiment to measure oxygen consumed by fish respiration and biofilteration and fish growth with the growth period and to validate the model results was carried out. The oxygen consumption predicted by the model was in a good agreement with those measured by the system. The oxygen consumption by fish respiration ranged 12.04 to 47.53 g O2 m−3 h−1 experimentally, while it was from 12.01 to 46.06 g O2 m−3 h−1 theoretically. The predicted and measured oxygen consumption through biofilteration values ranged from 0.43 to 21.91 and 0.45 to 23.09 g O2 m−3 h−1, respectively. The individual fish weight from the system ranged from 3.00 to 209.52 g experimentally while it was from 3.00 to 226.25 g theoretically during the whole period.

THERAPEUTIC EFFECT OF SINGLET OXYGEN ADMINISTRATION ON CRYSTALLIZATION OF RATS’ BLOOD SERUM AT THERMAL TRAUMA

Biological and therapeutic effects of singlet oxygen have not been investigated yet. The aim of this paper is to estimate the influence of a short course (10 days) of singlet oxygen inhalations on crystallogenic properties of rats’ blood serum. The experiment was performed on 30 male Wistar rats, randomly divided into three equal groups. The first group was intact. The animals of the 2nd (control) and 3rd (test) groups under combined anesthesia were subjected to thermal trauma. Starting from the day following the injury, the rats of the test group inhaled daily the air flow from a singlet oxygen generator during 10 days. Blood samples were obtained from the rats of all groups. Dried samples were evaluated visually for crystallizability, structure index, facia destruction degree, and marginal zone clarity, using respective scales. It is stated that singlet oxygen inhalations facilitate the elimination of negative transformations in blood crystallization induced by thermal trauma. It indicates the positive rehabilitation potential.

Integration Strategy of ROS Boosting and Antioxidation Inhibiting Initiates Ferroptosis to Enhance Phototherapic Effect on Tumor

Conventional phototherapy is often limited by hypoxia, introducing oxygen generators is the common method to relieve it, but the antioxidant path of tumor cell was inevitably initiated. Herein, by integrating oxygen generator (MnO2) and inhibitor of Nrf2 (brusatol) into one nanoplatform, we strive to relieve hypoxia and inhibit the antioxidation simultaneously. Hypoxia was relieved for the triggered decomposition of MnO2 by endogenous H2O2 and it directly strengthened photodynamic therapy (PDT) through boosting reactive oxygen species (ROS) generation. Moreover, high level ROS greatly enhanced the efficacy of photothermal therapy (PTT) by attacking heat shock proteins(HSP). Antioxidant defense was prevented by brusatol through inhibiting the expression of Nrf2. Importantly, MnO2 and brusatol collaboratively induced ferroptosis through raising oxidation, remarkably promoting tumor curative effect. Both in vitro and in vivo experiments demonstrated the strengthened therapeutic effects of synergistic PDT/PTT, highlighting the great promise of the synergistic modulation strategy with a nanomedicine to overcome the drawbacks of phototherapy.

The Possible Coupling of LNG Regasification Process with the TSA Method of Oxygen Separation from Atmospheric Air

Liquefied Natural Gas (LNG) must be vaporized before it is used in the combustion process. In most regasification terminals, energy that was previously expended to liquefy natural gas is dissipated in the environment. The paper proposes the use of the thermal effect of LNG regasification for the atmospheric air separation as a possible solution to the LNG exergy recovery problem. The presented idea is based on the coupling of the LNG regasification unit with an oxygen generator based on the Temperature Swing Adsorption (TSA) process. Theoretical analysis has revealed that it is thermodynamically justified to use the LNG enthalpy of vaporization for cooling of the TSA adsorption bed for increasing its adsorptive capacity. It has been shown that 1 kg of LNG carries enough exergy for separating up to approximately 100 g of oxygen using the TSA method. Although the paper suggests using the enthalpy of LNG vaporization for atmospheric air separation, similar processes for other gas mixture separations using the TSA method can be applied.