TY - CONF TI - Assessing Sequential Disinfection Performance in a Flow Through System Using a Non-Biological Surrogate AU - Richards, B.H. AU - Baeza, C. AU - Ducoste, J. T2 - American Water Works Association (AWWA) Research Symposium C2 - 2004/// C3 - Proceedings, AWWA Research Symposium CY - Baltimore, Maryland DA - 2004/// PY - 2004/4/18/ ER - TY - CONF TI - Modeling Spatial Distribution of Floc size in Turbulent Processes Using Quadrature Method of Moment and Computational Fluid Dynamics AU - Prat, O. AU - Ducoste, J.J. T2 - 2nd International Conference on Population Balance Modeling C2 - 2004/// CY - Valencia, Spain DA - 2004/// PY - 2004/5/5/ ER - TY - CONF TI - Numerical Prediction of Mixing Performance for Chloramines Formation AU - Ducoste, J.J. AU - Liu, Y. T2 - American Water Works Association (AWWA) Water Quality Technology Conference C2 - 2004/// C3 - Proceedings AWWA Water Quality Technology Conference CY - San Antonio, TX DA - 2004/// PY - 2004/// ER - TY - CONF TI - Numerical Prediction of the Reduction Equivalent Fluence Bias AU - Ducoste, J.J. AU - Linden, K.G. AU - Rokjer, D. T2 - American Water Works Association (AWWA) Water Quality Technology Conference C2 - 2004/// C3 - Proceedings AWWA Water Quality Technology Conference CY - San Antonio, TX DA - 2004/// PY - 2004/// ER - TY - SOUND TI - Performance Analysis of Quadrature Method of Moments (QMOM) for PBM Systems used in Assessing Flocculation Processes in Water and Wastewater Treatment AU - Prat, O. AU - Ducoste, J.J. DA - 2004/// PY - 2004/// ER - TY - SOUND TI - Characterizing Sequential Disinfection in Flow Through Systems AU - Richards, B. AU - Ducoste, J.J. DA - 2004/// PY - 2004/// ER - TY - SOUND TI - Characterization of Dose Distribution in UV Reactors AU - Ducoste, J.J. DA - 2004/// PY - 2004/// ER - TY - SOUND TI - Numerical Prediction of the Reduction Equivalent Fluence Bias, Invited Presentation at Degremont North AU - Ducoste, J.J. DA - 2004/// PY - 2004/// ER - TY - BOOK TI - Advances in Population Balance Modeling A3 - Nopens, I. A3 - Malise, K. A3 - Biggs, C. A3 - Ducoste, J.J. DA - 2004/// PY - 2004/// PB - Eurosis ER - TY - CONF TI - System-wide optimization of wastewater treatment plants using genetic algorithms C2 - 2004/// C3 - Bridging the Gap: Meeting the World's Water and Environmental Resources Challenges - Proceedings of the World Water and Environmental Resources Congress 2001 DA - 2004/// DO - 10.1061/40569(2001)106 VL - 111 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-75649101286&partnerID=MN8TOARS ER - TY - CONF TI - Lessons for applying computational fluid dynamics modeling to disinfection clearwells AU - Peplinski, D.K. AU - Ducoste, J.J. AB - Computational Fluid Dynamics (CFD) modeling offers the potential of improving disinfection contactor hydraulics, allowing a decrease in the applied disinfectant dose without a decrease in the level of microbial inactivation. For treatment systems utilizing chlorine as a disinfectant, this would result in both a reduction in chemical costs and in disinfection by-products (DBPs). Current modeling of clearwell hydraulics is based on accurate prediction of the effluent residence time distribution (RTD) curve. Researchers have shown that CFD models can predict a majority of the experimental RTD curve, but under certain circumstances may not reproduce the entire curve. The objectives of this study were to numerically characterize tracer transport through a disinfection contactor, investigate the impact of grid density, time step interval, and investigate the impact of accurately modeling perforated baffles on the resulting RTD curve. C2 - 2004/// C3 - Bridging the Gap: Meeting the World's Water and Environmental Resources Challenges - Proceedings of the World Water and Environmental Resources Congress 2001 DA - 2004/// DO - 10.1061/40569(2001)22 VL - 111 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-75649146660&partnerID=MN8TOARS ER - TY - BOOK TI - Engineering economic analysis AU - Donald G. Newnan, Ted G. Eschenbach AU - Lavelle, Jerome P. DA - 2004/// PY - 2004/// PB - New York: Oxford University Press ER - TY - CONF TI - The North Carolina State University women in science and engineering program: a community for living and learning AU - Rajala, S. A. AU - Bottomley, L.J. AU - Parry, E. A. AU - Cohen, J. D. AU - Grant, S. C. AU - Thomas, C. J. AU - Doxey, T. M. AU - Perez, G. AU - Collins, R. E. AU - Spurlin, J. E. C2 - 2004/// C3 - American Society for Engineering Education DA - 2004/// ER - TY - CHAP TI - Engineering computing as an essential component of inquiry-guided learning AU - Rohrbach, R. AU - Spurlin, J. AU - Mayberry, K AU - Rajala, S. T2 - Teaching and learning through inquiry: A guidebook for institutions and instructors PY - 2004/// PB - Sterling, VA: Stylus Publishing ER - TY - JOUR TI - Utilization of electron impact ionization of gaseous and sputtered species in the secondary ion acceleration region of a magnetic sector SIMS instrument AU - Pivovarov, A AU - Gu, C AU - Stevie, F AU - Griffis, D T2 - APPLIED SURFACE SCIENCE AB - Negative secondary ion insulator analysis using a normal incidence electron gun (NEG) on CAMECA magnetic sector SIMS instruments can be difficult due to an inability to adequately determine the electron beam impact region during NEG alignment. The electron impact energy is too low to utilize phosphor cathodoluminescent materials that can be used for NEG alignment for positive secondary ion analyses. Detection of electron beam desorbed H− is often used for NEG alignment, but the presence of H on the surface is not always uniform and it is transient, making it difficult to determine whether variations in the H− secondary ion intensity are due to non-uniformity of the electron beam or of the H on the sample. To overcome this difficulty, a new technique has been developed that takes advantage of sputtering of the sample surface by positive ions created by electron impact ionization in the spectrometer secondary ion acceleration region between the sample and the immersion lens of the mass spectrometer. The formation of the ions occurs by interaction of residual gas species in the spectrometer secondary ion acceleration region with the NEG electron beam. This method is used to align the NEG for negative secondary ion charge neutralization. DA - 2004/6/15/ PY - 2004/6/15/ DO - 10.1016/j.apsusc.2004.03.069 VL - 231 SP - 781-785 SN - 1873-5584 KW - charge neutralization KW - electron gun KW - negative secondary ions KW - magnetic sector ER - TY - JOUR TI - Special Issue - Secondary Ion Mass Spectrometry SIMS XIV - Proceedings of the Fourteenth International Conference on Secondary Ion Mass Spectrometry and Related Topics - San Diego, California, USA, September 14-19, 2003 - Preface AU - Hunter, J AU - Schueler, BW AU - Stevie, FA T2 - APPLIED SURFACE SCIENCE DA - 2004/6/15/ PY - 2004/6/15/ DO - 10.1016/j.apsusc.2004.03.206 VL - 231 SP - 1-2 SN - 0169-4332 ER - TY - JOUR TI - O-2(+) versus Cs+ for high depth resolution depth profiling of III-V nitride-based semiconductor devices AU - Kachan, M AU - Hunter, J AU - Kouzminov, D AU - Pivovarov, A AU - Gu, J AU - Stevie, F AU - Griffis, D T2 - APPLIED SURFACE SCIENCE AB - Abstract Optimum depth resolution with adequate sensitivity for the elements of interest is required to obtain the information desired from SIMS analysis of multilayer nitride III–V structures. For many of the species of interest, particularly the p-type dopants, O2+ bombardment at low energy is often used. Use of Cs+ bombardment and detection of the cesium attachment secondary ions (CsM+ where M is the element of interest) may provide several advantages over O2+ analysis. Using similar low primary ion impact energy analysis conditions for O2+ and Cs+ on CAMECA IMS-6f and IMS-4f instruments, the depth resolution obtained for positive secondary ions is compared. DA - 2004/6/15/ PY - 2004/6/15/ DO - 10.1016/j.apsusc.2004.03.211 VL - 231 SP - 684-687 SN - 1873-5584 KW - Cs cluster ions KW - GaN KW - depth resolution ER - TY - CHAP TI - Storage-efficient stateless group key revocation AU - Wang, P. AU - Ning, P. AU - Reeves, D. S. T2 - Information security: 7th international conference, ISC 2004, Palo Alto, CA, USA, September 27-29, 2004: Proceedings A2 - K. Zhang, A2 - Zheng, Y. AB - Secure group communication relies on secure and robust distribution of group keys. A stateless group key distribution scheme is an ideal candidate when the communication channel is unreliable. Several stateless group key distribution schemes have been proposed. However, these schemes require all users store a certain number of auxiliary keys. The number of such keys increases as the group size grows. As a result, it is quite challenging to use these schemes when the users in a relatively large group have memory constraints. Thus, it is desirable to develop new schemes that can reduce the memory requirement. This paper introduces two novel stateless group key revocation schemes named key-chain tree (KCT) and layered key-chain tree (LKCT), which combine one-way key chains with a logical key tree. These schemes reduce the user storage requirements by trading off it with communication and computation costs. Specifically, these schemes can revoke any R users from a user group of size N by sending a key update message with at most 4R keys, while only requiring each user to store 2log N keys. CN - QA76.9 .A25 I85 2004 PY - 2004/// DO - 10.1007/978-3-540-30144-8_3 VL - 3225 SP - 25-38 PB - Berlin; New York: Springer SN - 3540232087 ER - TY - JOUR TI - Novel testing system for evaluating the thermal stability of polyol ester lubricants AU - Wang, DX AU - Mousavi, P AU - Hauser, PJ AU - Oxenham, W AU - Grant, CS T2 - INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH AB - This paper reports the development of a novel testing system for evaluating the thermal stability of polyol ester lubricants. The thermal degradation of three pentaerythritol tetrapelargonate based lubricants in the temperature range of 180−220 °C was studied using the developed comprehensive system. The system includes (1) a high-temperature quartz crystal microbalance for the real-time, in situ measurement of the solid residual deposition on metal surfaces and the viscosity change of thermally stressed liquid phase; (2) an on-line gas chromatograph for monitoring the volatiles generation in real time; and (3) an off-line gel permeation chromatograph for determining the molecular weight distribution of the liquid-phase products. The results indicate that the strategy can provide an integrated picture of the thermal stability of lubricants by providing quantitative, real-time, in situ information on gas-, liquid-, and solid-phase products during the thermal decomposition of the lubricants. DA - 2004/10/13/ PY - 2004/10/13/ DO - 10.1021/ie030782f VL - 43 IS - 21 SP - 6638-6646 SN - 0888-5885 ER - TY - CHAP TI - Improving robustness of PGP keyrings by conflict detection AU - Jiang, Q. L. AU - Reeves, D. S. AU - Ning, P. T2 - Topics in cryptology, CT-RSA 2004 AB - Secure authentication frequently depends on the correct recognition of a user’s public key. When there is no certificate authority, this key is obtained from other users using a web of trust. If users can be malicious, trusting the key information they provide is risky. Previous work has suggested the use of redundancy to improve the trustworthiness of user-provided key information. In this paper, we address two issues not previously considered. First, we solve the problem of users who claim multiple, false identities, or who possess multiple keys. Secondly, we show that conflicting certificate information can be exploited to improve trustworthiness. Our methods are demonstrated on both real and synthetic PGP keyrings, and their performance is discussed. CN - QA76.9 .A25 C822 2004 PY - 2004/// DO - 10.1007/978-3-540-24660-2_16 VL - 2964 SP - 194-207 PB - Berlin; New York: Springer SN - 3540209964 ER - TY - JOUR TI - Improved charge neutralization method for depth profiling of bulk insulators using O-2(+) primary beam on a magnetic sector SIMS instrument AU - Pivovarov, AL AU - Stevie, FA AU - Griffis, DP T2 - APPLIED SURFACE SCIENCE AB - Use of electrons for charge neutralization during positive secondary ion SIMS analysis of insulators has typically been achieved using coincident primary ion and electron beams. The normal incidence electron gun on CAMECA magnetic sector SIMS instruments can effectively eliminate sample charging during analysis of thin insulating films if the electron energy is sufficient to penetrate the film. However, positive secondary ion SIMS bulk insulator analysis using this instrument can be difficult, especially if high sputtering rates are required. A neutralization method has been developed utilizing electron beam impact of a region adjacent to the sputtered area. Prior to analysis, the surface of the sample is coated with gold which provides a conductive surface layer and which has a high secondary and backscattered electron yield. Results have been obtained showing excellent neutralization for a variety of bulk insulators including glass, silica, alumina, and lithium niobate. Sputtering rates exceeding 2 nm/s have been achieved in bulk silica. The technique should be applicable to minerals and possibly for other materials in cases where the analyzed area cannot be directly irradiated with an electron beam. DA - 2004/6/15/ PY - 2004/6/15/ DO - 10.1016/j.apsusc.2004.03.070 VL - 231 SP - 786-790 SN - 1873-5584 KW - charge neutralization KW - electron gun KW - magnetic sector ER - TY - JOUR TI - Evaluation of alternative fluence rate distribution models AU - Liu, D AU - Ducoste, J AU - Jin, S AU - Linden, K T2 - JOURNAL OF WATER SUPPLY RESEARCH AND TECHNOLOGY-AQUA AB - Research Article| September 01 2004 Evaluation of alternative fluence rate distribution models Dong Liu; Dong Liu 1Department of Civil, Construction, and Environmental Engineering, North Carolina State University, 208 Mann Hall CB 7908, Raleigh, NC 27695-7908, USA Search for other works by this author on: This Site PubMed Google Scholar Joel Ducoste; Joel Ducoste 1Department of Civil, Construction, and Environmental Engineering, North Carolina State University, 208 Mann Hall CB 7908, Raleigh, NC 27695-7908, USA E-mail: jducoste@eos.ncsu.edu Search for other works by this author on: This Site PubMed Google Scholar Shanshan Jin; Shanshan Jin 2Degremont North American Research & Development Center, 510 E. Jackson St, Richmond, VA 23219, USA Search for other works by this author on: This Site PubMed Google Scholar Karl Linden Karl Linden 3Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708-0287, USA Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2004) 53 (6): 391–408. https://doi.org/10.2166/aqua.2004.0031 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Twitter LinkedIn Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation Dong Liu, Joel Ducoste, Shanshan Jin, Karl Linden; Evaluation of alternative fluence rate distribution models. Journal of Water Supply: Research and Technology-Aqua 1 September 2004; 53 (6): 391–408. doi: https://doi.org/10.2166/aqua.2004.0031 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex A detailed evaluation of several fluence rate distribution models was performed. These models included line source integration (LSI), multiple points source summation (MPSS), multiple segment source summation (MSSS), UVCalc3D, RAD-LSI, view factor and discrete ordinate (DO). As part of the evaluation, a complete MSSS model, which accounts for the quartz sleeve thickness when calculating the refraction angles, was developed. In addition, a simple attenuation factor was introduced to integrate the physics of reflection, refraction and absorption effects into the LSI model. As an alternative simple correction to the LSI, the RAD-LSI incorporates the RADIAL intensity model into the original LSI formulation. All models were compared with experimental measurements using spherical actinometers, which measure the fluence rate at specific points in space. Experimental measurements were performed in air and water. Experiments in water were performed at two different ultraviolet transmittance (UVTs) (77 and 88%). The results showed that models that neglected the effects of refraction deviated significantly from the experimental data. In addition, the MSSS approach or models that incorporated the MSSS concept were found to best match the experimentally measured fluence rate distribution. Moreover, little difference was found between the results of MSSS with quartz sleeve thickness and UVCalc3D, which does not model the quartz sleeve thickness in the refraction angle calculation but uses a factor to account for the effects of the quartz sleeve on the fluence rate. The attenuation factor combined with the LSI model was found to match the MSSS model predictions, while reducing the computational cost. disinfection, fluence rate, model, spherical actinometry, UV This content is only available as a PDF. © IWA Publishing 2004 You do not currently have access to this content. DA - 2004/9// PY - 2004/9// DO - 10.2166/aqua.2004.0031 VL - 53 IS - 6 SP - 391-408 SN - 1365-2087 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-6344252713&partnerID=MN8TOARS KW - disinfection KW - fluence rate KW - model KW - spherical actinometry KW - UV ER - TY - CHAP TI - Certificate recommendations to improve the robustness of web of trust AU - Jiang, Q. L. AU - Reeves, D. S. AU - Ning, P. T2 - Information security: 7th international conference, ISC 2004, Palo Alto, CA, USA, September 27-29, 2004: Proceedings A2 - K. Zhang, A2 - Zheng, Y. AB - Users in a distributed system establish webs of trust by issuing and exchanging certificates amont themselves. This approach does not require a central, trusted keyserver. The distributed web of trust, however, is susceptible to attack by malicious users, who may issue false certificates. In this work, we propose a method for generating certificate recommendations. These recommendations guide the users in creating webs of trust that are highly robust to attacks. To accomplish this we propose a heuristic method of graph augmentation for the certificate graph, and show experimentally that it is close to optimal. We also investigate the impact of user preferences and non-compliance with these recommendations, and demonstrate that our method helps identify malicious users if there are any. CN - QA76.9 .A25 I85 2004 PY - 2004/// DO - 10.1007/978-3-540-30144-8_25 VL - 3225 SP - 292-303 PB - Berlin; New York: Springer SN - 3540232087 ER - TY - JOUR TI - Secondary ion mass spectrometry backside analysis of barrier layers for copper diffusion AU - Gu, C AU - Pivovarov, A AU - Garcia, R AU - Stevie, F AU - Griffis, D AU - Moran, J AU - Kulig, L AU - Richards, JF T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B AB - Secondary ion mass spectrometry (SIMS) backside analyses have been performed on a Cu/TaN/Ta/SiO2/Si structure to determine barrier effectiveness for Cu diffusion. Sample backside access to the barrier layers was obtained by removal of the Si substrate using a polishing method that maintains parallelism between the sample surface and the polished back side by monitoring changes in facets at the four corners of the specimen. Determination of the Si thickness remaining during the polishing process was improved through the use of optical interference measurements using a narrow band pass optical filter. Samples having slopes with respect to the original surface less than 6 nm over 60 μm have been obtained. A difference in polishing rate between SiO2 and Si was exploited to obtain this parallelism. For SIMS analyses, the presence of a SiO2 layer required electron gun charge neutralization for the O2+ 0.5 keV impact energy analysis. SIMS analyses show the ability to distinguish all layers and to monitor copper through the barrier material. With the high depth resolution conditions used, SIMS analyses were able to provide detailed elemental distribution information such as the presence of nitrogen at specific interfaces. DA - 2004/// PY - 2004/// DO - 10.1116/1.1617278 VL - 22 IS - 1 SP - 350-354 SN - 1071-1023 ER - TY - JOUR TI - Diffusion profiles of high dosage Cr and V ions implanted into silicon AU - Zhang, P AU - Stevie, F AU - Vanfleet, R AU - Neelakantan, R AU - Klimov, M AU - Zhou, D AU - Chow, L T2 - JOURNAL OF APPLIED PHYSICS AB - The depth profiles of high dosage Cr+52 and V+51 ions implanted in (100) crystalline silicon after thermal anneal at temperatures between 300 °C and 1000 °C are studied by secondary ion mass spectrometry and cross-sectional transmission electron microscopy. At dosages of 1×1015 ions/cm2 and above, the surface layer of silicon substrate is amorphorized. During the subsequent thermal annealing, the depth profiles of the implanted ions are strongly coupled with the solid phase epitaxial growth of amorphous silicon. Silicide precipitate formation is important to understand the differences between Cr and V diffusion. After anneal of the 1×1015 ions/cm2 implanted samples at 900 °C and 1000 °C, most of the Cr has left the silicon, but only 10% of the V has escaped. The 1×1014 ions/cm2 Cr-implanted sample shows Cr ions exist only near the surface after 1000 °C anneal. The V-implanted sample, on the other hand, only shows a narrowing of the V profile after 1000 °C anneal. DA - 2004/7/15/ PY - 2004/7/15/ DO - 10.1063/1.1756221 VL - 96 IS - 2 SP - 1053-1058 SN - 1089-7550 ER - TY - JOUR TI - Bandwidth provisioning and pricing for networks with multiple classes of service AU - Fulp, EW AU - Reeves, DS T2 - COMPUTER NETWORKS AB - Network service providers purchase large point-to-point connections from network owners, then offer individual users network access at a price. Appropriately provisioning (purchasing) and allocating (pricing) connections remains a difficult problem due to increasing demands and network dynamics. However, connection management is more complex with the deployment of Quality of Service (QoS). This paper describes a scalable connection management strategy for QoS-enabled networks. The management technique maximizes profit, while reducing blocking experienced by users. Important issues regarding demand estimation, connection duration, and pricing intervals, are addressed and analyzed. Simulation results are also provided to demonstrate the viability of the proposed system. DA - 2004/9/16/ PY - 2004/9/16/ DO - 10.1016/j.comnet.2004.03.018 VL - 46 IS - 1 SP - 41-52 SN - 1872-7069 KW - connection management KW - SLA KW - DiffServ KW - bandwidth pricing KW - microeconomics ER - TY - JOUR TI - Modeling low-energy mixers for chemical dispersion in water treatment AU - Ortiz, V AU - Ducoste, JJ T2 - ENVIRONMENTAL ENGINEERING SCIENCE AB - A study has been conducted to evaluate the use of computational fluid dynamics (CFD) for analyzing the mixing effectiveness of low-energy mixers in water and wastewater treatment processes. In this study, CFD was used to predict experimental downstream mean tracer concentration and segregation intensity in different closed conduit reactor geometries. Mixing configurations include a plane shear layer, plane jet in a square conduit, a round jet in a circular conduit, and a hydraulic jet in a 1- and 6-in. diameter pipe. Tracer transport was approximated as a single fluid with the standard k-ε, Chen-Kim k-ε, RNG k-ε turbulence models and as a multifluid with the standard k-ε turbulence model. The results showed that the multifluid model better predicted the mean concentration than the single-fluid model. Multifluid model r2 values were significantly higher than the single-fluid model r2 values. The multifluid model also predicted the downstream segregation intensity values for the plane jet and round jet configurations. In addition, the multifluid model was able to predict the degradation in mixing performance moving from the 1- to 6-in. diameter hydraulic jet mixers operating under constant-jet momentum ratio. No significant improvement was found in the single-fluid model predictions by changing the turbulence model. Overall, the results show that CFD has the potential to enhance engineering experience by permitting the evaluation of different low energy-mixer alternatives. DA - 2004/// PY - 2004/// DO - 10.1089/109287504773087408 VL - 21 IS - 2 SP - 241-261 SN - 1557-9018 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-1542513928&partnerID=MN8TOARS KW - CFD KW - chemical mixing KW - turbulence KW - modeling ER - TY - JOUR TI - A non-biological surrogate for sequential disinfection processes AU - Baeza, C AU - Ducoste, J T2 - WATER RESEARCH AB - An evaluation of Fluorescent YG-microspheres (Polysciences Inc.) was performed to simulate Cryptosporidium parvum (C. parvum) oocysts inactivation in treatment systems that utilize multiple disinfectants. Experiments were conducted in batch reactors that included an ozone primary stage and a secondary free chlorine treatment stage. A flow cytometer was used to track changes in the fluorescence intensity distribution due to exposure to the chemical disinfectant. Microsphere ‘survival ratios’ (N/No) were calibrated by selecting an appropriate fluorescence intensity threshold to replicate the inactivation of different C. parvum oocysts strains. Results showed that fluorescent microspheres displayed synergistic effects in the presence of two sequential disinfectants. In addition, microsphere structural tests showed that the polystyrene surface was damaged due to exposure to ozone. This polystyrene damage enhanced the diffusion of the secondary disinfectant into the microsphere, where dye was degraded in the opened polymer layer. As a result, YG-fluorescent microspheres is a promising non-biological technique that is capable of producing similar synergistic behavior as with C. parvum oocysts exposed to ozone followed by chlorine. DA - 2004/// PY - 2004/// DO - 10.1016/j.watres.2004.04.029 VL - 38 IS - 14-15 SP - 3400-3410 SN - 0043-1354 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3342922732&partnerID=MN8TOARS KW - Crymosporidium parvum KW - free chlorine KW - microspheres KW - non-biological surrogate KW - ozone KW - sequential disinfection ER - TY - JOUR TI - Quartz crystal microbalance (QCM) in high-pressure carbon dioxide (CO2): Experimental aspects of QCM theory and CO2 adsorption AU - Wu, YT AU - Akoto-Ampaw, PJ AU - Elbaccouch, M AU - Hurrey, ML AU - Wallen, SL AU - Grant, CS T2 - LANGMUIR AB - The quartz crystal microbalance (QCM) technique has been developed into a powerful tool for the study of solid-fluid interfaces. This study focuses on the applications of QCM in high-pressure carbon dioxide (CO2) systems. Frequency responses of six QCM crystals with different electrode materials (silver or gold) and roughness values were determined in helium, nitrogen, and carbon dioxide at 35-40 degrees C and at elevated pressures up to 3200 psi. The goal is to experimentally examine the applicability of the traditional QCM theory in high-pressure systems and determine the adsorption of CO2 on the metal surfaces. A new QCM calculation approach was formulated to consider the surface roughness contribution to the frequency shift. It was found that the frequency-roughness correlation factor, Cr, in the new model was critical to the accurate calculation of mass changes on the crystal surface. Experiments and calculations demonstrated that the adsorption (or condensation) of gaseous and supercritical CO2 onto the silver and gold surfaces was as high as 3.6 microg cm(-2) at 40 degrees C when the CO2 densities are lower than 0.85 g cm(-3). The utilization of QCM crystals with different roughness in determining the adsorption of CO2 is also discussed. DA - 2004/4/27/ PY - 2004/4/27/ DO - 10.1021/la035502f VL - 20 IS - 9 SP - 3665-3673 SN - 0743-7463 ER - TY - JOUR TI - Capacity planning of DiffServ networks with best-effort and Expedited Forwarding traffic AU - Wu, KH AU - Reeves, DS T2 - TELECOMMUNICATION SYSTEMS AB - For networks providing a specific level of service guarantees, capacity planning is an imperative part of network management. Accurate dimensioning is especially important in DiffServ networks, where no per-flow signaling or control exists. In this paper, we address the problem of capacity planning for DiffServ networks with only Expedited Forwarding (EF) and best effort (BE) traffic classes. The problem is formulated as an optimization problem, where the total link cost is minimized, subject to the performance constraints of both EF and BE classes. The edge to edge EF demand pairs and the BE demands on each link are given. The variables to be determined are the non-bifurcated routing of EF traffic, and the discrete link capacities. We show that Lagrangian relaxation and subgradient optimization methods can be used to effectively solve the problem. Computational results show that the solution quality is verifiably good while the running time remains reasonable on practical-sized networks. This represents the first work for capacity planning of multi-class IP networks with non-linear performance constraints and discrete link capacity constraints. DA - 2004/// PY - 2004/// DO - 10.1023/B:TELS.0000014781.92903.7f VL - 25 IS - 3-4 SP - 193-207 SN - 1572-9451 KW - DiffServ KW - capacity planning KW - Lagrangian relaxation ER - TY - JOUR TI - Site-specific SIMS backside analysis AU - Gu, C AU - Garcia, R AU - Pivovarov, A AU - Stevie, F AU - Griffis, D T2 - APPLIED SURFACE SCIENCE AB - For maximum SIMS depth resolution for any layer in a sample, the depth profile should begin only as far from the layer as necessary to establish a constant implant concentration of the primary ion beam species. Depth resolution and detection limit can be severely degraded if it is necessary to sputter through an over layer having non uniform sputtering properties or containing a high level of the impurity of interest prior to reaching the layer of interest. A SIMS backside analysis method based on mechanical polishing is extended to allow site-specific SIMS backside depth profile analysis. Optical microscopy employing a red filter was used to allow direct viewing of the site to be depth profiled both during polishing and in situ during SIMS analysis. Depth profile analyses were performed on 100μm×100 μm device test structures. Sample charging resulting from insulator layers present in these device test structures was alleviated using a modified sample mounting technique. Backside SIMS depth profile analysis using an O2+ primary ion beam having an impact energy of 1.25 keV was used to determine if boron had penetrated a thin SiO2 layer. DA - 2004/6/15/ PY - 2004/6/15/ DO - 10.1016/j.apsusc.2004.03.140 VL - 231 SP - 663-667 SN - 1873-5584 KW - SfMS KW - backside analysis KW - semiconductors KW - patterned wafers ER -