Using GIS, Genetic Algorithms, and Visualization in Highway Development

A model for highway development is presented, which uses geographic information systems (GIS), genetic algorithms (GA), and computer visualization (CV). GIS serves as a repository of geographic information and enables spatial manipulations and database management. GAs are used to optimize highway alignments in a complex search space. CV is a technique used to convey the characteristics of alternative solutions, which can be the basis of decisions. The proposed model implements GIS and GA to find an optimized alignment based on the minimization of highway costs. CV is implemented to investigate the effects of intangible parameters, such as unusual land and environmental characteristics not considered in optimization. Constrained optimization using GAs may be performed at subsequent stages if necessary using feedback received from CVs. Implementation of the model in a real highway project from Maryland indicates that integration of GIS, GAs, and CV greatly enhances the highway development process.     

Measurement and Correlation of Surface Tension for Single Aqueous Electrolyte Solutions

In this study, the values of the surface tension for a number of single aqueous electrolyte solutions were measured at various temperatures and electrolyte concentrations using the well-known and computer-aided pendant-drop method. In order to conduct the experimental measurements, a high-pressure IFT-700 apparatus, equipped with a view cell and a data acquisition system, was used. The systems studied in this study were aqueous solutions of KCl, NaCl, CaCl₂, and Na₂SO₄. The pooled standard deviation and the confidence limit of the surface-tension data for a 95 % confidence level were determined to be 0.17 mN · m^?1 and ${\bar{\sigma} \pm 0.19}$ , respectively. It should be noted that while the surface tension for electrolyte solutions increases as the electrolyte concentration increases, it decreases with an increase in temperature as expected. Finally, data reduction was carried out using an empirical equation to show the effect of temperature, electrolyte concentration, and the nature of ionic species on the surface tension for the systems studied.     

Thermal properties of particulate TIMs in squeeze flow

Direct numerical simulations based on a thermal Lattice–Boltzmann method are utilized to compute the effective thermal conductivity of particulate thermal interface materials (TIMs). By simulating the squeezing process, we obtain the particle distribution in a situation similar to application. Therefore, there is no need to calculate the average thermal characteristics from several pre-defined random distributions. The effects of particle volume fraction, particle size, and particle to matrix thermal conductivity ratio on the thermal performance are investigated. The results for the effective thermal conductivity are in agreement with the existing semi-analytical and experimental results reported in the literature.     

Comparison of risk assessment methodologies for exposure of mink to PCBs on the Kalamazoo River, Michigan

Risk assessments are generally based on exposures predicted by use of simple models of accumulation from abiotic compartments or the diet. The use of tissue-specific measurements of residue concentrations in wildlife tissues is more accurate and subject to less uncertainty, but these data are often not available. This report compares the results of two different site-specific approaches for assessing the risk of PCBs to mink residing along the Kalamazoo River, MI. The first approach was based on hepatic concentrations of PCBs and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) of mink. The second approach was based on measured concentrations of both PCBs and TEQs in the diets of mink. For each of these methodologies, assessments were based on no observed adverse effect levels (NOAELs) or concentrations (NOAECs) and lowest observed adverse effect levels (LOAELs) or concentrations (LOAECs). Samples of mink (Mustela vison) and its diet were collected from within the Kalamazoo River Area of Concern (KRAOC) and an upstream reference area in the Fort Custer Recreation Area (FC). Hazard quotient (HQ) values were calculated based on congener-specific concentrations of PCBs or TEQs, several toxicity reference values (TRVs), and several assumed dietary compositions. Mean total hepatic concentrations of PCBs were 2.7 and 2.3 mg PCBs/kg, ww, in mink from the KRAOC and FC, respectively. HQs based on the LOAEC and mean hepatic PCB concentrations ranged from 0.37 to 0.87 at KRAOC and 0.31-0.73 at FC. HQs based on PCBs in the diet ranged from 0.20 to 1.8 at KRAOC and from 0.04 to 0.35 at FC. Dietary HQs were less than 10-fold different than tissue-based HQs.     

A multi-threshold online smoothing technique for variable rate multimedia streams

Variable bit rate (VBR) compression for media streams allocates more bits to complex scenes and fewer bits to simple scenes. This results in a higher and more uniform visual and aural quality. The disadvantage of the VBR technique is that it results in bursty network traffic and uneven resource utilization when streaming media. In this study we propose an online media transmission smoothing technique that requires no a priori knowledge of the actual bit rate. It utilizes multi-level buffer thresholds at the client side that trigger feedback information sent to the server. This technique can be applied to both live captured streams and stored streams without requiring any server side pre-processing. We have implemented this scheme in our continuous media server and verified its operation across real world LAN and WAN connections. The results show smoother transmission schedules than any other previously proposed online technique. This research has been funded in part by NSF grants EEC-9529152 (IMSC ERC), and IIS-0082826, DARPA and USAF under agreement nr. F30602-99-1-0524, and unrestricted cash/equipment gifts from NCR, IBM, Intel and SUN. Roger Zimmermann is currently a Research Assistant Professor with the Computer Science Department and a Research Area Director with the Integrated Media Systems Center (IMSC) at the University of Southern California. His research activities focus on streaming media architectures, peer-to-peer systems, immersive environments, and multimodal databases. He has made significant contributions in the areas of interactive and high quality video streaming, collaborative large-scale group communications, and mobile location-based services. Dr. Zimmermann has co-authored a book, a patent and more than seventy conference publications, journal articles and book chapters in the areas of multimedia and databases. He was the co-chair of the ACM NRBC 2004 workshop, the Open Source Software Competition of the ACM Multimedia 2004 conference, the short paper program systems track of ACM Multimedia 2005 and will be the proceedings chair of ACM Multimedia 2006. He is on the editorial board of SIGMOD DiSC, the ACM Computers in Entertainment magazine and the International Journal of Multimedia Tools and Applications. He has served on many conference program committees such as ACM Multimedia, SPIE MMCN and IEEE ICME. Cyrus Shahabi is currently an Associate Professor and the Director of the Information Laboratory (InfoLAB) at the Computer Science Department and also a Research Area Director at the NSF's Integrated Media Systems Center (IMSC) at the University of Southern California. He received his M.S. and Ph.D. degrees in Computer Science from the University of Southern California in May 1993 and August 1996, respectively. His B.S. degree is in Computer Engineering from Sharif University of Technology, Iran. He has two books and more than hundred articles, book chapters, and conference papers in the areas of databases and multimedia. Dr. Shahabi's current research interests include Peer-to-Peer Systems, Streaming Architectures, Geospatial Data Integration and Multidimensional Data Analysis. He is currently an associate editor of the IEEE Transactions on Parallel and Distributed Systems (TPDS) and on the editorial board of ACM Computers in Entertainment magazine. He is also the program committee chair of ICDE NetDB 2005 and ACM GIS 2005. He serves on many conference program committees such as IEEE ICDE 2006, ACM CIKM 2005, SSTD 2005 and ACM SIGMOD 2004. Dr. Shahabi is the recipient of the 2002 National Science Foundation CAREER Award and 2003 Presidential Early Career Awards for Scientists and Engineers (PECASE). In 2001, he also received an award from the Okawa Foundations. Kun Fu is currently a Ph.D candidate in computer science from the University of Southern California. He did research at the Data Communication Technology Research Institute and National Data Communication Engineering Center in China prior to coming to the United States and is currently working on large scale data stream recording architectures at the NSF's Integrated Media System Center (IMSC) and Data Management Research Laboratory (DMRL) at the Computer Science Department at USC. He received an MS in engineering science from the University of Toledo. He is a member of the IEEE. His research interests are in the area of scalable streaming architectures, distributed real-time systems, and multimedia computing and networking. Mehrdad Jahangiri was born in Tehran, Iran. He received the B.S. degree in Civil Engineering from University of Tehran at Tehran, in 1999. He is currently working towards the Ph.D. degree in Computer Science at the University of Southern California. He is currently a research assistant working on multidimensional data analysis at Integrated Media Systems Center (IMSC)—Information Laboratory (InfoLAB) at the Computer Science Department of the University of Southern California.     

A new technique for micro-patterning of nanoparticles on non-conductive substrate by low frequency AC electrophoresis

Electrophoretic deposition (EPD) has been known as a cost-effective and simple method in shaping or coating ceramic parts. Usefulness of this electrically driven method becomes more pronounced when it is applied for manipulating nanosize materials. Our findings in this area have showed that nanoparticle manipulation with EPD method is possible through applying low frequency alternating current (AC) electric fields. In our previous work, we explained how nanoparticles fill the non-conductive gap between two in-plane electrodes at frequency of 1 Hz. In this work, we used the similar idea to deposit TiO₂ nanoparticles on non-conductive Alumina base in direction parallel to the electrode edge. The length and width of TiO₂ deposited line was in the order of micrometer and coherency of deposited layer was good. It was concluded that with designing different electrode shapes, micro-patterning of ceramic nanoparticles on different substrates via low frequency AC electrophoretic deposition is possible.     

Effect of hydrothermal duration on synthesis of WO<Subscript>3</Subscript> nanorods

Among different type of transition metal oxides, tungsten trioxide (WO₃) is a suitable candidate for electronic device fabrication due to its n-type property and wide band gap. Herein, one-dimensional tungsten trioxide (WO₃) nanorods were achieved from an aqueous solution of sodium tungstate dihydrate (Na₂WO₄·2H₂O) and sodium chloride (NaCl) in an acidic media by a time-optimized hydrothermal synthesis in autoclave at 180°C or different synthesis durations. For studying morphology and size of obtained powder, X-ray diffraction (XRD), scanning electron microscope (SEM), and high resolution transmission electron microscope (HRTEM) were applied. Finally, WO₃ nanorods of about 2–3 μm in length and 100–200 nm in diameter were obtained during 3 h hydrothermal process.     

Conversion of CO into CO2 by high active and stable PdNi nanoparticles supported on a metal-organic framework

The solubility of Pd(NO₃)₂ in water is moderate whereas it is completely soluble in diluted HNO₃ solution. Pd/MIL-101(Cr) and Pd/MIL-101-NH₂(Cr) were synthesized by aqueous solution of Pd(NO₃)₂ and Pd(NO₃)₂ solution in dilute HNO₃ and used for CO oxidation reaction. The catalysts synthesized with Pd(NO₃)₂ solution in dilute HNO₃ showed lower activity. The aqueous solution of Pd(NO₃)₂ was used for synthesis of mono-metal Ni, Pd and bimetallic PdNi nanoparticles with various molar ratios supported on MOF. Pd₇₀Ni₃₀/MIL-101(Cr) catalyst showed higher activity than monometallic counterparts and Pd+ Ni physical mixture due to the strong synergistic effect of PdNi nanoparticles, high distribution of PdNi nanoparticles, and lower dissociation and desorption barriers. Comparison of the catalysts synthesized by MIL-101(Cr) and MIL-101-NH₂(Cr) as the supports of metals showed that Pd/MIL-101-NH₂(Cr) outperforms Pd/MIL-101-(Cr) because of the higher electron density of Pd resulting from the electron donor ability of the NH₂ functional group. However, the same activities were observed for Pd₇₀Ni₃₀/MIL-101(Cr) and Pd₇₀Ni₃₀/MIL-101-NH₂(Cr), which is due to a less uniform distribution of Pd nanoparticles in Pd₇₀Ni₃₀/MIL-101-NH₂(Cr) originated from amorphization of MIL-101-NH₂(Cr) structure during the reduction process. In contrast, Pd₇₀Ni₃₀/MIL-101(Cr) revealed the stable structure and activity during reduction and CO oxidation for a long time.     

Dielectric Environment Sensitivity of Carbon Centers in Hexagonal Boron Nitride

A key advantage of utilizing van-der-Waals (vdW) materials as defect-hosting platforms for quantum applications is the controllable proximity of the defect to the surface or the substrate allowing for improved light extraction, enhanced coupling with photonic elements, or more sensitive metrology. However, this aspect results in a significant challenge for defect identification and characterization, as the defect's properties depend on the the atomic environment. This study explores how the environment can influence the properties of carbon impurity centers in hexagonal boron nitride (hBN). It compares the optical and electronic properties of such defects between bulk-like and few-layer films, showing alteration of the zero-phonon line energies and their phonon sidebands, and enhancements of inhomogeneous broadenings. To disentangle the mechanisms responsible for these changes, including the atomic structure, electronic wavefunctions, and dielectric screening, it combines ab initio calculations with a quantum-embedding approach. By studying various carbon-based defects embedded in monolayer and bulk hBN, it demonstrates that the dominant effect of the change in the environment is the screening of density–density Coulomb interactions between the defect orbitals. The comparative analysis of experimental and theoretical findings paves the way for improved identification of defects in low-dimensional materials and the development of atomic scale sensors for dielectric environments.     

Recent Advances in Stimuli-Responsive Smart Membranes for Nanofiltration

Nanofiltration membrane plays an increasingly important role in many industrial applications, such as water treatment and resource recovery. The performance of the smart nanofiltration membrane is largely controlled by pore size, the Donnan effect, and surface wettability, which are determined by the function of stimuli-responsive components. Smart membranes, which contain stimuli-responsive components, are capable of changing their physical and chemical properties in response to changes in the environment so that the microstructure of the membrane will have more efficient performances and broader application prospects than the current traditional nanofiltration membranes. Herein, the preparation methods of stimuli-responsive membranes are described and they are systematically classified accordingly to their mechanisms. Moreover, the latest progress of stimuli-responsive membranes in nanofiltration and the main mechanism of each stimuli-response type through relevant examples are discussed and summarized. Finally, this review provides new insights into the remaining challenges and future directions of stimuli-responsive membranes. Fueled by advances in chemistry and materials science, it is expected to build a smart and efficient nanofiltration membrane platform for the benefit of mankind.