Effects of pH and surface modification of TiO2 with SiOx on the photocatalytic degradation of a pyrimidine derivative

A pyrimidine derivative, 2-isopropyl-6-methyl-4-pyrimidinol (IMP), could be completely decomposed following pseudo-first-order kinetics by photocatalytic reaction using TiO₂. The effects of pH and surface modification of TiO₂ with SiO_x were studied. The degradation rate of IMP was fast in mild acidic condition (pH=6.3) and slower in strong acidic (pH=2.0) or basic (pH=10.0) condition. The main reason of the slow IMP degradation was different in strong acidic and basic conditions. In strong acidic condition, the slow degradation rate was explained by electrostatic repulsion. On the other hand, a little formation of hydroxyl radicals was considered as a main reason in strong basic condition. The result was supported by the experiments using SiO_x-loaded TiO₂, which has a lower isoelectric point than pure TiO₂.     

Genetic and environmental influences on the continuous scales of the Myers-Briggs Type Indicator: an analysis based on twins reared apart

The effects of 1/1000 field recommended concentration of the organophosphorus compounds; edifenphos and glyphosate on the immune response and protein contents were investigated after different time intervals. The cell mediated immune response assessed by proliferative response of splenocytes to mitogens; phytohemagglutinin (PHA) and concanavalin A (Con A) for T cell and lipopolysaccharide (LPS) for B cell decreased significantly in tems of the level of stimulation index in the treated fish and reached maximal depression after 4 weeks. Humoral immunity assessed as splenic antibody plaque forming cells (PFC) measured after 5 days in vitro immunization to sheep erythrocytes (SRBC's) were suppressed in a concentration dependent pattern by the two compounds. The estimated ED50 for the PFC/10(6) cells of edifenphos and glyphosate were 1.48 x 10(-2) uM and 1.65 x 10(-2) uM respectively. The data also showed that serum antibody titres in the treated fish were decreased in a time dependent manner. The total protein content of serum treated with the two pesticides was decreased after different time periods compared with control. The blood serum of treated and untreated Tilapia nilotica were analyzed electrophoretically for protein components and the percentage of proteins in each fraction was determined.     

Robust nonlinear generalised minimum variance control and fault monitoring

The first part of this paper extends the Nonlinear Generalised Minimum Variance (NGMV) controller to improve the robustness of its control or set-point tracking performance. This is achieved by replacing the Kalman filter included in the original NGMV controller with an observer to minimise the effect of uncertainty, which includes unknown disturbance, modelling error, and faults. The observer design also allows the NGMV controller to be utilised in fault monitoring. More specifically, the second part of this paper obtains the observer gain by solving a multi-objective optimisation problem through the application of a genetic algorithm so that the residual signal becomes sensitive to faults and insensitive to any other uncertainty. The control and fault monitoring performance of the extended NGMV controllers is tested by application to a nonlinear tank model.     

Performance analysis for bounded persistent disturbances in PD/PID-controlled robotic systems with its experimental demonstrations

This paper is concerned with performance analysis of proportional-derivative/proportional-integral-derivative (PD/PID) controller for bounded persistent disturbances in a robotic manipulator. Even though the notion of input-to-state stability (ISS) has been widely used to deal with the effect of disturbances in control of a robotic manipulator, the corresponding studies cannot be directly applied to the treatment of persistent disturbances occurred in robotic manipulators. This is because the conventional studies relevant to ISS consider the H_∞ performance for robotic systems, which is confined to the treatment of decaying disturbances, i.e. the disturbances those in the L₂ space. To deal with the effect of persistent disturbances in robotic systems, we first provide a new treatment of ISS in the L_∞ sense because bounded persistent disturbances should be intrinsically regarded as elements of the L_∞ space. We next derive state-space representations of trajectory tracking control in the robotic systems which allow us to define the problem formulations more clearly. We then propose a novel control law that has a PD/PID control form, by which the trajectory tracking system satisfies the reformulated ISS. Furthermore, we can obtain a theoretical argument about the L_∞ gain from the disturbance to the regulated output through the proposed control law. Finally, experimental studies for a typical 3-degrees of freedom robotic manipulator are given to demonstrate the effectiveness of the method introduced in this paper.     

Secure proof of storage with deduplication for cloud storage systems

Explosion of multimedia content brings forth the needs of efficient resource utilization using the state of the arts cloud computing technologies such as data deduplication. In the cloud computing environments, achieving both data privacy and integrity is the challenging issue for data outsourcing service. Proof of Storage with Deduplication (POSD) is a promising solution that addresses the issue for the cloud storage systems with deduplication enabled. However, the validity of the current POSD scheme stands on the strong assumption that all clients are honest in terms of generating their keys. We present insecurity of this approach under new attack model that malicious clients exploit dishonestly manipulated keys. We also propose an improved POSD scheme to mitigate our attack.     

Numerical study on the effects of a synthetic jet actuator on S809 airfoil aerodynamics at different flow regimes and jet flow angles

Due to importance of active flow control methods for future Horizontal axis wind turbines (HAWT), we numerically investigated the effects of Synthetic jet actuators (SJA) on the separation and aerodynamic lift enhancement of a finite span wing with the S809 airfoil. The investigation was performed at a realistic AOA range (0°~25°), which is associated to a wide range of AOA, from an attached flow to a highly separated condition. Also, effects of SJA injection angle on flow characteristics at a highly separated condition were studied. The unsteady simulations were performed using DES turbulence model. The results show that for an attached flow, the SJA triggers an early separation and reduces the lift coefficients. However, for a separated flow, the SJA considerably enhances lift performance. In addition, at small AOAs the lift values fluctuate harmonically over time; however, as the AOA increases and the separation becomes severe, the lift becomes more chaotic. Finally, a study of the present SJA configuration reveals that the SJA can enhance the lift values at a wide range of injected flow angle. However, lift values do not show distinguished pattern for different jet angles at a high AOA.

     

Effect of salt concentration on production of polyunsaturated fatty acids in <Emphasis Type="Italic">Thraustochytrium aureum</Emphasis> ATCC 34304

This study attempted to characterize the effects of NaCl and MgSO₄ as the primary components of sea salt affecting the yields of production of polyunsaturated fatty acids (PUFAs) by Thraustochytrium aureum ATCC 34304. Reductions in the NaCl concentration of the culture medium suppressed the formation of palmitic acid (PA, C16: 0) but enhanced the production of PUFAs, which induced an increase of the concentration of docosahexaenoic acid (DHA, C22: 6) up to 46.65% from 44.26%. MgSO₄ revealed a similar, yet more highly significant, effect on the fatty acids profile than NaCl. The yields of PUFAs and DHA showed maximum values such as 67.10% and 49.47%, respectively, at the concentration of 10 g L⁻¹ for NaCl and 0 g L⁻¹ for MgSO₄. However, the quantities of mono-and diunsaturated fatty acids, oleic acid (OA, C18: 1) and linoleic acid (LA, C18: 2) at the same concentrations, were compared with those of normal culture medium. Additionally, it was investigated that the increase of culture temperature reduced PUFAs contents but the reductions were recovered by the removal of MgSO₄ form the culture medium, which showed that concentration of salts and culture temperature affected independently the production of PUFAs in T. aureum.     

Polymer property control in a continuous styrene polymerization reactor using model-on-demand predictive controller

The model-on-demand (MoD) framework was extended to the model predictive control (MPC) to design a multiple variable model-on-demand predictive controller (MoD-PC). This control algorithm was applied to the property control of polymer product in a continuous styrene polymerization reactor. For this purpose, a local auto-regressive exogenous input (ARX) model was constructed with a small portion of data located in the region of interest at every sample time. With this model an output prediction equation was formulated to calculate the optimal control input sequence. Jacket inlet temperature and conversion were chosen as the elements of regressor state vector in data searching step. Simulation studies were conducted by applying the MoD-PC to MIMO control problems associated with the continuous styrene polymerization reactor. The control performance of the MoD-PC was then compared with that of a nonlinear MPC based on the polynomial auto-regressive moving average (ARMA) model for disturbance rejection as well as for setpoint-tracking. As a result, the MoD-PC was found to be an effective strategy for the production of polymers with desired properties.