Sustainable Basin-Scale Water Allocation with Hydrologic State-Dependent Multi-Reservoir Operation Rules

This study extends the PSO-MODSIM model, integrating particle swarm optimization (PSO) algorithm and MODISM river basin decision support system (DSS) to determine optimal basin-scale water allocation, in two aspects. The first is deriving hydrologic state-dependent (conditional) operating rules to better account for drought and high-flow periods, and the second is direct, explicit consideration of sustainability criteria in the model’s formulation to have a better efficiency in basin-scale water allocation. Under conditional operating rules, the operational parameters of reservoir target storage levels and their priority rankings were conditioned on the hydrologic state of the system in a priority-based water allocation scheme. The role of conditional operating rules and policies were evaluated by comparing water shortages associated with objective function values under unconditional and conditional operating rules. Optimal basin-scale water allocation was then evaluated by incorporating reliability, vulnerability, reversibility and equity sustainability indices into the PSO objective function. The extended model was applied for water allocation in the Atrak River Basin, Iran. Results indicated improved distribution of water shortages by about 7.5% using conditional operating rules distinguishing dry, normal and wet hydrologic states. Alternative solutions with nearly identical objective function values were found with sustainability indices included in the model.     

Vitamin A microencapsulation within poly(methyl methacrylate)‐g‐polyethylenimine microspheres: Localized proton buffering effect on vitamin A stability

To stabilize vitamin A in a cosmetic/dermatological formulation, we present here a new encapsulation method based on polymer microspheres having a localized “proton‐buffering” capacity. Poly(methyl methacrylate)‐g‐polyethylenimine (PMMA‐g‐PEI) was prepared by direct condensation grafting of PEI onto poly(methyl methacrylate‐co‐methyl acrylic acid). The reaction was confirmed by FT‐IR analysis showing the amide vibration at 1,550 cm^?1. Elemental analysis indicated that the weight content of the grafted PEI was 1.6% (w/w). Vitamin A was encapsulated into PMMA‐g‐PEI microspheres by using an oil‐in‐water (O/W) single emulsion method. The presence of PEI moiety dramatically improved the chemical stability of vitamin A in microspheres. Vitamin A encapsulated within PMMA‐g‐PEI microspheres maintained 91% of its initial activity after 30‐day incubation at 40°C, while only maintaining 60% within plain PMMA microspheres. This study demonstrates that proton‐buffering within hydrophobic polymer matrix is a useful strategy for stabilizing “acid‐labile” active ingredients. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 517–522, 2004     

Efective Object Identification and Association by Varying Coverage Through RFID Power Control简

This paper presents an effective power scheduling strategy for energy efficient multiple objects identification and association. The proposed method can be utilized in many heterogeneous surveillance systems with visual sensors and RFID （radio-frequency identification） readers where energy efficiency as well as association rate are critical Multiple objects positions and trajectory estimates are used to decide the power level of RFID readers. Several key parameters including the time windows and the distance separations are defined in the method in order to minimize the effects of RFID coverage uncertainty. The power cost model is defined and incorporated into the method to minimize energy consumption and to maximize association performance. The proposed method computes the power cost using the range of the outermost position for possible single association and group associations at every sampling time. An RFID reader is activated with the proper coverage range when the power cost for the current time is lower than the power cost for the next time sample. The simplicity of the power cost model relieves the problematic combinatorial comparisons in multiple object cases. The performance comparison simulation with the minimum and maximum energy consumption shows that the proposed method achieves fast single associations with less energy consumption. Finally, the realistic comparison simulation with the fixed range RFID readers demonstrates that the proposed method outperforms the fixed ranges in terms of single association rate and energy consumption.     

Production of human normal adult and fetal hemoglobins in Escherichia coli

A hemoglobin expression system in Escherichia coli is described. In order to produce authentic human hemoglobin, we need to co-express both methionine aminopeptidase and globin genes under the control of a strong promoter. We have constructed three plasmids, pHE2, pHE4 and pHE7, for the expression of human normal adult hemoglobin and a plasmid, pHE9, for the expression of human fetal hemoglobin, in high yields. The globin genes can be derived from either synthetic genes or human globin cDNAs. The extra amino-terminal methionine residues of the expressed globins can be removed by the co-expressed methionine aminopeptidase. The heme is inserted correctly into the expressed alpha- globin from our expression plasmids. A fraction (approximately 25%) of the heme is not inserted correctly into the expressed beta- or gamma- globin. However, the incorrectly inserted hemes can be converted into the correct conformation by carrying out a simple oxidation-reduction process on the purified hemoglobin molecule. We have investigated the functional properties of the expressed hemoglobins by measuring their oxygen-binding properties and their structural features by obtaining their 1H-NMR spectra. Our results show that authentic human normal adult and fetal hemoglobins can be produced from our expression plasmids in E. coli and in high yields. Our expression system allows us to design and to produce any recombinant hemoglobins needed for our research on the structure-function relationship in hemoglobin.      

Kinetics of cellobiose decomposition under subcritical and supercritical water in continuous flow system

The effects of reaction temperature, pressure and residence time were investigated with a flow apparatus. Cellobiose decomposition kinetics and products in suband supercritical water were examined at temperatures from 320 to 420 °C at pressures from 25 to 40 MPa, and at residence times within 3 sec. Cellobiose was found to decompose via hydrolysis and pyrolysis. The yield of desired hydrolysis product, glucose, was the maximum value of 36.8% at 320 °C, 35 MPa, but the amount of 5-(hydroxymethyl)furfural (HMF), fermentation inhibitor increased too because residence time increased in the subcritical region owing to decrease of reaction rate. Meanwhile, though the yield of glucose is low in the supercritical region, the yield of HMF decreased compared with the subcritical region; and at the minimum yield of HMF (380 °C, 25 MPa), the yield of glucose was 21.4%. The decomposition of cellobiose followed first-order kinetics and the activation energy for the decomposition of cellobiose was 51.05 kJ/mol at 40MPa.     

Control of the photorefractive effect using a low Tg sol-gel glass

Summary We prepared the photorefractive sol-gel glass based on organic-inorganic hybrid materials containing a charge transporting molecule, second-order nonlinear optical chromophore, photosensitizer, and plasticizer. Carbazole and 2-{ 4-[(2-hydroxyethyl) methylamino]benzylidene}malononitrile were reacted with 3-isocyanatopropyl triethoxysilane and the functionalized silanes were employed to fabricate the efficient photorefractive media including 2,4,7-trinitrofluorenone (TNF) to form a charge transfer complex. The simplest way to vary the composition in the matrix was to mix the desired amount of the functionalized alkoxysilane. The prepared sol-gel glass samples contained a large amount of nonlinear optical (NLO) chromophore compared to that of the charge transporting molecules. They showed a large net gain coefficient and high diffraction efficiency at certain conditions. Received:27 May 2002/Revised version:23 August 2002/Accepted:7 September 2002 Correspondence to Dong Hoon Choi E-mail: dhchoi@khu.ac.kr     

High-Resolution Electron Microscopy Observations of Stacking Faults in β-SiC

Structural images of the stacking faults in β-SiC were obtained with a high-resolution electron microscope. Stacking faults initially present in β-SiC powder particles were eliminated as grain growth proceeded at elevated temperatures.     

4D MRI Flow Coupled to Physics‐Based Fluid Simulation for Blood‐Flow Visualization

Modern MRI measurements deliver volumetric and time‐varying blood‐flow data of unprecedented quality. Visual analysis of these data potentially leads to a better diagnosis and risk assessment of various cardiovascular diseases. Recent advances have improved the speed and quality of the imaging data considerably. Nevertheless, the data remains compromised by noise and a lack of spatiotemporal resolution. Besides imaging data, also numerical simulations are employed. These are based on mathematical models of specific features of physical reality. However, these models require realistic parameters and boundary conditions based on measurements. We propose to use data assimilation to bring measured data and physically‐based simulation together, and to harness the mutual benefits. The accuracy and noise robustness of the coupled approach is validated using an analytic flow field. Furthermore, we present a comparative visualization that conveys the differences between using conventional interpolation and our coupled approach.     

Direct equivalence between geometric conditions and algebraic conditions for discrete-time nonlinear observer

Unlike the continuous-time case, algebraic necessary and sufficient conditions for a single output discrete-time system to be state equivalent to a nonlinear observer canonical form have been found and are easier to verify for those who are not accustomed to differential geometry. The geometric conditions look very different from the algebraic conditions. In this paper, we show direct equivalence of the geometric conditions and the algebraic conditions in order to enhance the understanding of the geometric conditions.     

A microfluidic device for thermal particle detection

We demonstrate the use of heat to count microscopic particles. A thermal particle detector (TPD) was fabricated by combining a 500-nm-thick silicon nitride membrane containing a thin-film resistive temperature detector with a silicone elastomer microchannel. Particles with diameters of 90 and 200 μm created relative temperature changes of 0.11 and ?0.44 K, respectively, as they flowed by the sensor. A first-order lumped thermal model was developed to predict the temperature changes. Multiple particles were counted in series to demonstrate the utility of the TPD as a particle counter.