Monitoring therapeutic processes using risk-adjusted multivariate Tukey's CUSUM control chart

Using control charts for monitoring therapeutic processes has become popular lately. As the application of traditional control charts in the therapeutic processes may be misleading due to the inherent differences between patients, a multifactor correlated risk measure is considered in monitoring of these processes. Therefore, using risk-adjusted control charts for monitoring the therapeutic processes is of interest to practitioners. Furthermore, in health care monitoring, statistical models should account for abnormal distributions and outlier data to minimize misinterpretations of monitoring schemes. This study proposes a risk-adjusted multivariate Tukey's cumulative sum (RA-MTCUSUM) control chart. The proposed method is a combination of the accelerated failure time (AFT) regression model, the Tukey's control chart (TCC) featuring robustness against abnormality, and the multivariate cumulative sum (MCUSUM) control chart for monitoring multivariable process. Simulation experiments are performed to evaluate the performance of the proposed control chart using the average run length (ARL) measure. Results show that the RA-MTCUSUM control chart has better performance in comparison with traditional ones for monitoring various distributions (normal and non-normal). Based on the simulation results, outlier data do not disturb the proposed control chart's performance. Moreover, applying the RA-MTCUSUM control chart to a real-world dataset related to sepsis patients of a hospital located in Tehran, Iran indicates that the control chart has more reasonable performance than the traditional control charts in the real applications due to its robustness.     

Numerical solution of doubly singular nonlinear systems using neural networks-based integrated intelligent computing

Neural Computing and Applications - In this paper, a bio-inspired computational intelligence technique is presented for solving nonlinear doubly singular system using artificial neural networks...     

Simultaneous improvement of photocatalytic and superhydrophilicity properties of nano TiO2 thin films

Anatase TiO₂ nano thin films were prepared on glass substrates by sol–gel dip coating method using Tween-80 as a surfactant, TiCl₄ as the Ti precursor, and ethanol as a solvent. Atomic force microscopy, X-ray diffraction, and UV–Vis. photospectrometery experiments were performed to analyze the surface, structural and optical characteristics of the films. The effects of chemical aging time on the morphology, photocatalytic and superhydrophilicity behaviors of the films were studied. We show there is an optimum aging time at 2 h which photocatalytic and superhydrophilicity properties are at their maximum values simultaneously. This is useful in the self-cleaning industry.     

PHENOLIC WASTEWATER TREATMENT BY SUPPORTED LIQUID MEMBRANE USING DIFFERENT COOKING OILS AS LIQUID MEMBRANE

Transport of phenol through a flat sheet supported liquid membrane (SLM) containing cooking oil as liquid membrane (LM) was investigated. Factors affecting permeation of phenol such as membrane phase, support material, feed phase pH, stripping phase concentration, stirring speed, and initial concentration of phenol were studied. It was found that these parameters strongly influence phenol removal efficiency; PTFE membrane as support material, grape seed oil as liquid membrane, feed pH of 2.0, initial phenol concentration of 100 mg/L, stirring speed of 350 rpm, and 0.2 M sodium hydroxide as effective stripping agent were found as the best conditions for greater phenol transport. Under these conditions, permeability was found to be 7.46 × 10^?6 m/s. After 10.5 h, phenol was completely removed from the feed phase to strip phase. According to stability experiments, it was observed that the SLM is stable after 22 h. Thus, the use of cheap, nontoxic, and naturally oil as a novel and green membrane for recovery of phenol from wastewater was demonstrated.     

Free vibration analysis of variable thickness thin plates by two-dimensional differential transform method

This paper aims at extending the application of two-dimensional differential transform method (2D-DTM) to study the free vibration of thin plates with arbitrarily varying thickness. First, the differential equation of motion governing thin plates with varying thickness is derived using Hamilton’s principle. Afterward, the 2D-DTM, a numerical method which is capable of reducing the size of computational work and can be applied to various types of differential equations, has been applied to derive the natural frequencies of variable thickness thin plates with different boundary conditions. Several numerical examples have been carried out to demonstrate the applicability and accuracy of the present method in free vibration analysis of both uniform plates and plates with variable thickness.     

Study of Total Detection Efficiency (η) of Charge Exchange Analyzer (CXA) in TVD Tokamak

Diagnostic devices detection efficiency consist of many parameters. Contribution of each part in main detection efficiency need to study all aspect of devices and experimentally researches. In this paper experimental results and theoretical study merged to figure out the total detection efficiency of CXA. Most important primary parameters has been recognized (stripping foil thickness, incident energy, etc.) and effect of these parameters in related part studied. For CXA of TVD tokamak total detection efficiency presented and shown for 3 keV this parameter equal to .09 and stripping efficiency is equal 1.1 approximately. Choosing appropriate system for stripping of neutral beam is the most important factor in CXA diagnostic devices specially for high energy beams.     

Cyclic voltammetry and scanning electrochemical microscopy studies of methylene blue immobilized on the self-assembled monolayer of n-dodecanethiol

Electron transfer (ET) kinetics through n-dodecanethiol (C₁₂SH) self-assembled monolayer on gold electrode was studied using cyclic voltammetry (CV), scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS). An SECM model for compensating pinhole contribution, was used to measure the ET kinetics of solution-phase probes of ferrocyanide/ferricyanide (Fe(CN)₆^4−/3−) and ferrocenemethanol/ferrociniummethanol (FMC^0/+) through the C₁₂SH monolayer yielding standard tunneling rate constant () of (4 ± 1) × 10⁻¹¹ and (3 ± 1) × 10⁻¹⁰ cm s⁻¹ for Fe(CN)₆^4−/3− and FMC^0/+ respectively. Decay tunneling constants (β) of 0.97 and 0.96 Å⁻¹ for saturated alkane thiol chains were obtained using Fe(CN)₆⁴⁻ and FMC respectively. Also, it was found that methylene blue (MB) molecules are effectively immobilized on the C₁₂SH monolayer and can mediate the ET between the solution-phase probes and underlying gold substrate. SECM-mediated model was used to simultaneously measure the bimolecular ET between the solution-phase probes and the monolayer-immobilized MB molecules, as well as tunneling ET between the monolayer-immobilized MB molecules and the underlying gold electrode, allowing the measurement of k_BI = (5 ± 1) × 10⁶ and (4 ± 2) × 10⁷ cm³ mol⁻¹ s⁻¹ for the bimolecular ET and and (7 ± 3) × 10⁻² s⁻¹ for the standard tunneling rate constant of ET using Fe(CN)₆^4−/3− and FMC^0/+ probes respectively.     

Analysis of the Slider Off-Track Vibration Caused by the Aerodynamic Loads Associated With Different Components of a Head Stack Assembly in a Disk Drive

The paper describes a numerical investigation of the problem of flow-induced, off-track vibration of the slider in a disk drive. The flow field was simulated in a 3.5-in, 10 000 rpm disk drive using FLUENT flow-modeling software, which yielded the aerodynamic forces and moments for various components of the head stack assembly (HSA). The finite-element model of the HSA was developed using ANSYS software. Then off-track vibration of the slider caused by the aerodynamic loads of different HSA components was computed. The computations showed that the arm experiences the largest fluctuations of aerodynamic load. However, the loadbeam base region appears to make the largest contribution to off-track vibration of the slider, due to the vortex shedding generated by the side tabs of the loadbeam base region.     

An intelligent approach to the lateral forces usage in controlling the vehicle yaw rate

A direct yaw moment control system (DYC) is designed to improve the handling and stability of a four‐wheel‐drive electric vehicle. The main task of this paper is to use the lateral forces in the process of optimally controlling vehicle stability. This is performed by defining a variable optimum region for the slip ratio of each wheel. A hierarchical structure is selected to design the control system. The higher‐level control system controls the yaw rate of the vehicle based on the fuzzy logic technique. The lower‐level control system, installed in each wheel, maintains the slip ratio of the same wheel within an optimum region using the fuzzy logic technique. This optimum region for each wheel is continuously modified based on the impact of the lateral force on the generated control yaw moment and the friction coefficient of the road. Therefore, an algorithm for estimation of the friction coefficient is proposed. Computer simulations are carried out to investigate the effectiveness of the proposed method. This is accomplished by comparison of the results of control methods with a fixed slip ratio region and the results of the proposed method with a variable slip ratio region in some maneuvers. The robustness of the proposed controller against hard braking and noise contamination, as well as the effect of steering wheel angle amplitude, is verified. The simulation results show that the influence of the proposed method on enhancing vehicle performance is significant. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society