Effect of Adsorbent Grain Size on the Pressure Swing Adsorption

An analytical solution is obtained for a system of differential equations consisting of the equation for diffusion and absorption of a component in adsorbent grains and the balance equation for this component moving in the adsorbent layer.The technique for calculation of steady-state periodic adsorption processes based on expansion of a concentration signal into Fourier series of eigenfrequencies of this adsorption process is proposed. After decomposition each of the eigenwaves independently of the others is passed through the adsorbent layer, and at the output from this layer all this solutions for individual eigenwaves are summed. The solution to a problem of passing an arbitrary periodic concentration signal through the adsorbent layer is obtained as a result of summing the solutions for individual eigenwaves.The proposed method takes into account nonstationary diffusion processes inside the adsorbent grains. It makes possible to analyze effect of the adsorbent grain sizes on a pressure swing adsorption processes.

Wave Mathematical Model to Describe Gas Chromatography

This paper describes the mathematical model of concentration waves passing through a layer of adsorbent. The analytic solution to this model deduced for eigenwaves of adsorptive layer had been found. It allows finding the analytical decisions for concentration signal of arbitrary waveform passing through adsorbing layer. To do this the concentration signal at the input of the adsorption layer must be decomposed into the set of eigenwaves, and then to obtain the analytical solution for each of these proper concentration waves at the outlet of adsorbed layer. Next, all solutions for their proper concentration waves are combined into a new solution, which is the solution for an arbitrary concentration signal that passes through the adsorbent layer. This approach allows us to find solutions for any periodic adsorption processes and allows to consider the variable component concentrations or variable flow losses at the entrance to the adsorption layer. A wave approach to the analysis of periodic adsorption processes gives an explanation to the empirical Van Deemter equation used in the practice of gas chromatography.

Glucose Prediction and Hypoglycemia Alarms Based on Adaptive Model

The paper proposes a glucose prediction model and hypoglycemia alarms technology based on CGMS. Method: By using kalman filter to smooth the glucose data from the CGMS, reducing noise interference; Then according to the non-stationary characteristics of glucose concentration signal ,Using adaptive autoregressive model (AR) glucose prediction model is established; Finally, the prediction model is applied to hypoglycemia alarms. Results: The prediction model can dynamically capture the changes of the glucose and predict glucose of 30 min ahead, RMSE、SSGPE were 5.069,5.276; And hypoglycemia can be timely detected.

Regulation of AQP0 water permeability is enhanced by cooperativity

Aquaporin 0 (AQP0), essential for lens clarity, is a tetrameric protein composed of four identical monomers, each of which has its own water pore. The water permeability of AQP0 expressed in Xenopus laevis oocytes can be approximately doubled by changes in calcium concentration or pH. Although each monomer pore functions as a water channel, under certain conditions the pores act cooperatively. In other words, the tetramer is the functional unit. In this paper, we show that changes in external pH and calcium can induce an increase in water permeability that exhibits either a positive cooperativity switch-like increase in water permeability or an increase in water permeability in which each monomer acts independently and additively. Because the concentrations of calcium and hydrogen ions increase toward the center of the lens, a concentration signal could trigger a regulatory change in AQP0 water permeability. It thus seems plausible that the cooperative modes of water permeability regulation by AQP0 tetramers mediated by decreased pH and elevated calcium are the physiologically important ones in the living lens.

Study on the Mean Value of Particle Concentration Signal in Silicon Power Fluidized Bed

The particle concentration signals of silicon powder in the fluidizing gas i.e. air under different operating conditions were determined. The diameter of silicon particles, operating velocity, radial distance and axial distance are used as input vector; the mean value of particle concentration signal in the silicon power fluidized bed is used as a target vector. The RBF neural network is applied to build the predicted model of the mean value in silicon power fluidized bed. The result shows that the prediction of mean value through the RBF neural network is prior to that by BP neural network, and its error is less than 0.2%.

Study on Filter of Particle Concentration Signal in Silicon Powder Fluidized Bed

The concentration signal of silica powder in the fluidizing gas i.e. air under different operation conditions were determined. The pretreating effects of concentration signal of silica powder by low pass filtering, wavelet transform de-noising and wavelet packet de-noising were compared. And the optimum method of de-noising has been determined.