High-Performance Liquid Chromatographic Determination of Flavoxate Hydrochloride and its Hydrolysis Product

Liquid chromatographic method was presented for the determination of flavoxate hydrochloride (FX) and its hydrolysis product. The method was based on high-performance liquid chromatographic (HPLC) separation of FX from its hydrolysis product on CN column using a mobile phase consisting of acetonitrile-12 mM ammonium acetate (45:55, vol/vol, pH 4.0) with UV detection at 220 nm and flow rate of 1.5 mL min^?1. The proposed HPLC method for the determination of FX was utilized to investigate the kinetics of acidic hydrolytic process at different temperatures and to calculate its activation energy. In addition, the proposed HPLC method was used for pH-rate profile study of hydrolysis of FX in Britton–Robinson buffer solutions. The 3-methylflavone-8-carboxylic acid ethyl ester, as impurity of flavoxate hydrochloride, can be separated by the proposed HPLC method.     

Vector Control Scheme of Five-Phase Induction Machines under Open-Circuit Phase Faults

Multiphase induction machine is normally controlled using rotor field oriented vector control. Under phase（s） loss, the machine currents can be optimally controlled to satisfy certain optimization criteria. In this paper, a vector control scheme to a five-phase induction machine is introduced to ensure equal phase currents and minimum torque ripples under a phase open circuit. The controller idea can be extended to any number of phases with any number of open phases. The fundamental dq components of the stator voltage are obtained using only two PI controllers for the fundamental sequence plane, as in conventional vector control of three-phase machines. Based on steady state model, a simple expression is derived to estimate the required dq voltage components of other sequence planes to ensure equal stator phase currents and minimum torque ripple. A five-phase machine is simulated using MATLAB/Simulink to ensure controller validity.     

Distributed access management in multimedia IDCs

Future Internet data centers that provide multimedia content face security challenges requiring appropriately designed policies to manage resource access. An example from the healthcare domain shows how an access management framework can address these challenges.     

An Intelligent Knowledge-Based System for Product Cost Modelling

An intelligent knowledge-based system for product cost modellingis presented in this paper. The developed system has the capability of selecting a material, as well as machining processes and parameters based on a set of design and production parameters; and of estimating the product cost throughout the entire product development cycle including assembly cost. The proposed system is applied without the need for detailed design information, so that it can be used at an early design stage, and, consequently, redesign cost and longer lead time can be avoided. Hybrid knowledge representation techniques, such as production rules, frame and object oriented are employed to represent manufacturing knowledge. Fuzzy logic-based knowledge representation is applied to deal with uncertainty in the knowledge of cost model to generate reliable cost estimation. This paper deals with cost modelling of both a machining component and an injection moulding component, which is a process that gives high production rates, excellent quality and accuracy of products, and low manufacturing cost. Based on the analysis of the moulded product life cycle, a computer-based cost model was developed which integrated the relationship between cost factors, product development activities, and product geometry. The estimated cost included the costs of material, mould and processing. The system has been validated through a case study.     

Studies on the in vitro Release of Ibuprofen from Polyethylene Glycol-Polyvinyl Acetate Mixtures Liquid Filled into Hard Gelatin Capsules

The release of ibuprofen from mixtures of polyethylene glycol (PEG) with polyvinyl acetate (PVAc) has been studied in vitro and complemented by x-ray diffraction measurements, differential scanning calorimetry (DSC), and melting point determinations via hot-stage microscopy (HSM). Results indicate that ibuprofen release can be affected markedly by alteration of the PVAc concentration. The molecular weight of the PEG and the pH of the dissolution medium are also shown to affect the release profile. Visual observation during the drug release process revealed a complex behavior which included emission of liquidlike droplets, formation of a crust around the releasing mass, and/or production of flakes of solid material. This behavior appeared to have a disadvantageous effect on the reproducibility of drug release. Construction of a phase diagram from results of thermal analysis using DSC and HSM indicated the formation of an eutectic mixture with a composition of 35% ibuprofen and 65% PEG 1500 and a melting point of 36°C. The complex behavior of the drug-releasing mass is discussed in terms of this phase diagram. Only the release data for systems containing 4% w/w or more of PVAc could be linearized by plotting against the square root of time whereas data for all of the systems studied could be linearized by first-order plots.     

Applying quality control charts to the analysis of single-subject data sequences

Techniques from the field of quality control can be used to classify the quality of individual samples of physical or cognitive performance. After stable baselines have been established for an individual, deviations in performance can be evaluated using control charts. The effectiveness of this approach in evaluating cognitive performance was tested using databases collected under a variety of risk factors. The sensitivity and specificity characteristics of Shewhart, cumulative-sum (CUSUM), and exponentially weighted moving average (EWMA) control charts were determined for a total of 174 trials involving 10 participants and 23 cognitive performance assessment measures. The most effective technique in each case was typically a function of the specific performance measure and the type of performance change being evaluated. Sensitivity and specificity for the best techniques were as high as 100%. This study demonstrated the usefulness of quality control charts as a tool to evaluate individual participant performance over time. Actual or potential applications of this research include readiness-to-perform screening of industrial workers in order to improve the health and safety of the workforce.     

Privacy policies for shared content in social network sites

Social networking is one of the major technological phenomena of the Web 2.0, with hundreds of millions of subscribed users. Social networks enable a form of self-expression for users and help them to socialize and share content with other users. In spite of the fact that content sharing represents one of the prominent features of existing Social network sites, they do not provide any mechanisms for collective management of privacy settings for shared content. In this paper, using game theory, we model the problem of collective enforcement of privacy policies on shared data. In particular, we propose a solution that offers automated ways to share images based on an extended notion of content ownership. Building upon the Clarke-Tax mechanism, we describe a simple mechanism that promotes truthfulness and that rewards users who promote co-ownership. Our approach enables social network users to compose friendship based policies based on distances from an agreed upon central user selected using several social networks metrics. We integrate our design with inference techniques that free the users from the burden of manually selecting privacy preferences for each picture. To the best of our knowledge, this is the first time such a privacy protection mechanism for social networking has been proposed. We also extend our mechanism so as to support collective enforcement across multiple social network sites. In the paper, we also show a proof-of-concept application, which we implemented in the context of Facebook, one of today’s most popular social networks. Through our implementation, we show the feasibility of such approach and show that it can be implemented with a minimal increase in overhead to end-users. We complete our analysis by conducting a user study to investigate users’ understanding of co-ownership, usefulness and understanding of our approach. Users responded favorably to the approach, indicating a general understanding of co-ownership and the auction, and found the approach to be both useful and fair.     

Accelerating compute-intensive image segmentation algorithms using GPUs

Image segmentation is an important process that facilitates image analysis such as in object detection. Because of its importance, many different algorithms were proposed in the last decade to enhance image segmentation techniques. Clustering algorithms are among the most popular in image segmentation. The proposed algorithms differ in their accuracy and computational efficiency. This paper studies the most famous and new clustering algorithms and provides an analysis on their feasibility for parallel implementation. We have studied four algorithms which are: fuzzy C-mean, type-2 fuzzy C-mean, interval type-2 fuzzy C-mean, and modified interval type-2 fuzzy C-mean. We have implemented them in a sequential (CPU only) and a parallel hybrid CPU–GPU version. Speedup gains of 6\(\times \) to 20\(\times \) were achieved in the parallel implementation over the sequential implementation. We detail in this paper our discoveries on the portions of the algorithms that are highly parallel so as to help the image processing community, especially if these algorithms are to be used in real-time processing where efficient computation is critical.     

Secondary side post regulator for improving cross regulation and reducing standby power consumption

The quest for improved energy savings is driving research into power converter high-efficiency operation under extremely light-load conditions. The use of multiple output converters to satisfy circuit needs and cost requirements adds additional complication to the standby mode power-consumption problem. This is due to the difficulty of satisfying both good cross-regulation under various load conditions as well as high efficiency in the standby mode simultaneously; because topologies that exhibit a good cross-regulation performance, such as resonant converters, generally have a poor efficiency problem under extremely light-loads. A secondary side post regulator (SSPR) is proposed to reduce the standby power consumption and to improve the cross-regulation performance of single- controller multiple-output channel power converters. It is capable of reducing the power consumption of the power converter as well as the SSPR. The SSPR is analysed using its operational principles and small signal models. A 110?W experimental prototype was built to verify the standby power consumption and cross-regulation performance using the proposed SSPR.     

Concrete mixtures incorporating synthesized sulfonated acetophenone–formaldehyde resin as superplasticizer

Polymers in concrete have received considerable attention over the past 25 years. Water-soluble sulfonated acetophenone–formaldehyde (SAF) resin was produced in the laboratory from the reaction between acetophenone–formaldehyde, and sodium bisulfite. Its performance as a concrete admixture was evaluated through its effect on the (w/c) ratio, air content, setting time, compressive strength at different ages, water absorption and permeable pores. Also, the performance of the concrete when subjected to acidic environment using sulfuric acid (pH = 4), and sulphate attack using magnesium sulphate (pH = 6.5) were investigated. SAF resin could be classified as a high-range water reducer with retarding effect (Type F and G according to ASTM C494). It was found that concrete mixtures incorporating SAF resin-based admixture yielded higher compressive strength results compared with the control concrete mixtures, as well as they are more resistant to aggressive environments investigated due to the higher resistance to water movement.