Level Set Based Simulations of Two-Phase Oil–Water Flows in Pipes

We simulate the axisymmetric pipeline transportation of oil and water numerically under the assumption that the densities of the two fluids are different and that the viscosity of the oil core is very large. We develop the appropriate equations for core-annular flows using the level set methodology. Our method consists of a finite difference scheme for solving the model equations, and a level set approach for capturing the interface between two liquids (oil and water). A variable density projection method combined with a TVD Runge–Kutta scheme is used to advance the computed solution in time. The simulations succeed in predicting the spatially periodic waves called bamboo waves, which have been observed in the experiments of [Bai et al. (1992) J. Fluid Mech. 240, 97–142.] on up-flow in vertical core flow. In contrast to the stable case, our simulations succeed in cases where the oil breaks up in the water, and then merging occurs. Comparisons are made with other numerical methods and with both theoretical and experimental results.     

A vehicle routing problem solved by using a hybrid genetic algorithm

The main purpose of this study is to find out the best solution of the vehicle routing problem simultaneously considering heterogeneous vehicles, double trips, and multiple depots by using a hybrid genetic algorithm. This study suggested a mathematical programming model with a new numerical formula which presents the amount of delivery and sub-tour elimination. This model gives an optimal solution by using OPL-STUDIO(ILOG CPLEX). This study also suggests a hybrid genetic algorithm (HGA) which considers the improvement of generation for an initial solution, three different heuristic processes, and a float mutation rate for escaping from the local solution in order to find the best solution. The suggested HGA is also compared with the results of a general genetic algorithm and existing problems suggested by Eilon and Fisher. We found better solutions rather than the existing genetic algorithms.     

Nonsmooth feedback stabilizer for strict-feedback nonlinear systems that may not be linearizable at the origin

We present a continuous feedback stabilizer for nonlinear systems in the strict-feedback form, whose chained integrator part has the power of positive odd rational numbers. Since the power is not restricted to be larger than or equal to one, the linearization of the system at the origin may fail. Nevertheless, we show that the closed loop system is globally asymptotically stable (GAS) with the proposed continuous (but, possibly not differentiable) feedback. We formulate a condition that enables our design by characterizing the powers of the given system. The condition also shows that our result is an extension of Qian and Lin [Non-lipschitz continuous stabilizers for nonlinear systems with uncontrollable unstable linearization, Systems Control Lett. 42 (2001) 185–200] where the power of odd positive integers has been considered. New result on the global finite time stabilization problem is also presented.     

Data reuse algorithm for multiple reference frame motion estimation

A data reuse algorithm for multiple reference frame motion estimation is described. The proposed algorithm reduces memory access by modifying the reference frame search order and search centre such that the likelihood of data reuse is increased. Experimental results show that the algorithm reduces memory access by 15-30% compared to the conventional fast reference frame selection algorithm, while maintaining similar bit rate and PSNR     

An Experimental 0.8 V 256‐kbit SRAM Macro with Boosted Cell Array Scheme

This work presents a low‐voltage static random access memory (SRAM) technique based on a dual‐boosted cell array. For each read/write cycle, the wordline and cell power node of selected SRAM cells are boosted into two different voltage levels. This technique enhances the read static noise margin to a sufficient level without an increase in cell size. It also improves the SRAM circuit speed due to an increase in the cell read‐out current. A 0.18 µm CMOS 256‐kbit SRAM macro is fabricated with the proposed technique, which demonstrates 0.8 V operation with 50 MHz while consuming 65 µW/MHz. It also demonstrates an 87% bit error rate reduction while operating with a 43% higher clock frequency compared with that of conventional SRAM.     

An exploratory study of radio frequency identification (RFID) adoption in the healthcare industry

This study examines the radio frequency identification (RFID) adoption decision process and proposes a model predicting the likelihood of adopting RFID within organizations in the healthcare industry. A considerable number of studies have been conducted regarding organizational information technology (IT) adoption, but the nature of the organizational IT adoption process is still not well understood. Especially, although there are a number of variables and categories that have been found empirically to be related to adoption behavior, there is little in the way of evidence to suggest the origin or motivation behind the adoption. Thus, this study investigates the underlying motivations and driving forces behind the adoption of RFID using the theory of technology-push and need-pull. In this study, an organizational RFID adoption model is proposed and empirically tested by a survey using a sample of 126 senior executives in U.S. hospitals. The model posits that three categories of factors, technology push, need pull, and presence of champions, determine the likelihood of adopting RFID within organizations. This study also found that the relationships between those three categories and the likelihood of adopting RFID are strengthened or weakened by organizational readiness.     

Microfluidic Synthesis of pH‐Sensitive Multicompartmental Microparticles for Multimodulated Drug Release

Stimuli‐responsive carriers releasing multiple drugs have been researched for synergistic combinatorial cancer treatment with reduced side‐effects. However, previously used drug carriers have limitations in encapsulating multiple drug components in a single carrier and releasing each drug independently. In this work, pH‐sensitive, multimodulated, anisotropic drug carrier particles are synthesized using an acid‐cleavable polymer and stop‐flow lithography. The particles exhibit a faster drug release rate at the acidic pH of tumors than at physiological pH, demonstrating their potential for tumor‐selective drug release. The drug release rate of the particles can be adjusted by controlling the monomer composition. To accomplish multimodulated drug release, multicompartmental particles are synthesized. The drug release profile of each compartment is programmed by tailoring the monomer composition. These pH‐sensitive, multicompartmental particles are promising drug carriers enabling tumor‐selective and multimodulated release of multiple drugs for synergistic combination cancer therapy.     

Methodology to design the interfaces in SiC/Al composites

A methodology to control interfacial microstructures, while suppressing formation of Al₄C₃ in wrought Al alloy composites reinforced with SiC, was demonstrated. Thermodynamic calculations were carried out to elucidate how one can select process parameters in terms of alloy composition and fabrication temperature to obtain intended interfaces. Experimental verifications were conducted using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to validate calculated results. The reaction mechanisms for forming various interfaces were identified both theoretically and experimentally. Evaluations of the interfacial bonding strengths and interfacial stability at elevated temperatures were also carried out for various interface types.     

Production of bioethanol from waste money bills – A new cellulosic material for biofuels

Waste money bills that are no longer legal tender are non-recyclable and are usually destroyed. In this study, we used this cellulose-rich material for bioethanol fermentation for the first time. Glucose production was enhanced by using diluted H₂SO₄ during pretreatment. Different incubation periods were tested for saccharification and subsequent bioethanol fermentation. The highest yield of glucose (41.90 mg/ml) was shown to increase with 27.20% and 25.90% respectively by increasing the reaction period by 30 min and by increasing the acid concentration by 0.5%. Bioethanol production was enhanced by adding 0.4 mM benzoic acid under anoxic condition. In accordance with three different conditions, the highest amount of bioethanol (22.01 mg/ml) was obtained and bioethanol fermentation was increased by 59.38%, 110.02% and 64.13% respectively with 30 min of reaction periods, 0.5% of acid concentrations and under anoxic condition with benzoic acid. This procedure for the production of bioethanol from a waste material would reduce waste money bill management costs and make a profit from ethanol.     

Fabrication of YBa2Cu3Ox superconductor using Y2BaCuO5, BaCuO2 and CuO

YBa₂Cu₃O _x superconductor was synthesized using Y₂BaCuO₅, BaCuO₂, and CuO powder mixture. Reaction temperatures were identified using differential thermal analysis (DTA) and thermogravimetry (TG) for syntheses of precursor powders and the powder mixtures. Appropriate reaction temperatures for Y₂BaCuO₅ and BaCuO₂ precursor powders were 950 and 930°C, respectively. Two endothermic reactions involving melt formations were identified on the DTA and TG curves of the powder mixture, and the liquid increased the reactivity of the YBa₂Cu₃O _x formation. Powder mixture samples were sintered at various temperatures ranging from 880 to 1000°C. Microstructural and X-ray powder diffraction studies showed YBa₂Cu₃O _x and impurities to be formed in the samples sintered at various temperatures. The samples sintered at 990 and 1000°C showed dense microstructures. The critical temperature was 84 K for the sample sintered at 880°C and rose to 92 K as the sintering temperature increased.