bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of High Current Density at Nanoscale Point Contacts
Authors: Lo Hsinyi , Bain James A.
Published: June 2009

We examine the electrical/thermal contact between Pt-coated pyramidal Si probes and a 100 nm thick Au film using conductive atomic force microscopy (C-AFM). For all tips, the series resistance after initial contact was not a strong function of applied force over the observed range. Mechanical contact in this range of forces without an applied voltage between tip and Au film did not produce any observable tip deformation or wear as determined by SEM examination. Changes in tip morphology after applying voltage between the tips and Au film can be attributed to two different mechanisms. At relatively high applied voltages, evidence for tip melting was observed. Increases in tip/film contact resistance as a function of applied power allows an estimate of the thermal resistance experienced by heat generated at the tip and flowing to thermal ground. In addition to tip damage caused by melting, evidence was also seen of current induced welding of the Pt coating to the Au film in the absence of any significant heating at low applied voltages (10 mV). To explain the observation in the absence of sufficient temperature rise to induce melting, we characterize electromigration in the C-AFM and examine the maximum permissible current density of tips with different sizes as a function of stress.
Direct Numerical Simulation of the Interaction of an Ultra Short-Pulsed Intense Laser With a H2+ Molecule
Authors: Lee Y.-M. , Wu J.-S. , Jiang T.-F. , Chen Y.-S.
Published: June 2009

In this paper, interactions of a linearly polarized ultra short-pulsed intense laser with a single H2+ molecule at various angles of incidence are studied by directly solving the time-dependent three-dimensional Schrodinger equation (TDSE), assuming Born-Oppenheimer approximation. An explicit stagger-time algorithm is employed for time integration of the TDSE, in which the real and imaginary parts of the wave function are defined at alternative times, while a cell-centered finite-volume method is utilized for spatial discretization of the TDSE on Cartesian grids. The TDSE solver is then parallelized using domain decomposition method on distributed memory machines by applying a multi-level graph-partitioning technique. The solver is applied to simulate laser-molecular interaction with test conditions including: laser intensity of 0.5*1014 W/cm2, wavelength of 800 nm, three pulses in time, angle of incidence of 0–90° and inter-nuclear distance of 2 a.u.. Simulation conditions include 4 million hexahedral cells, 90 a.u. long in z direction, and time-step size of 0.005 a.u.. Ionization rates, harmonic spectra and instantaneous distribution of electron densities are then obtained from the solution of the TDSE. Future possible extension of the present method is also outlined at the end of this paper.
Natural Convective Heat Transfer of Water-in-FC72 Nanoemulsion Fluids
Authors: Han Zenghu , Yang Bao
Published: June 2009

The use of SOLID-particles has long been a common way of increasing fluid thermal conductivity. In this paper, nanoemulsion fluids—dispersions of LIQUID-nanodroplets—are proposed. As an example, water-in-FC72 nanoemulsion fluids are developed, and their thermophysical properties and impact on natural convective heat transfer are investigated experimentally. A significant increase in thermal conductivity—up to 52% for 12vol% of water nanodroplets (or 7.1 wt%)—is observed in the fluids. The enhancement in conductivity and viscosity of the fluids is found to be nonlinear with water loading, indicating an important role of the hydrodynamic interaction and aggregation of nanodroplets. However, the relative viscosity is found to be about two times the relative conductivity if compared at the same water loading. The presence of water nanodroplets is found to systematically increase the natural convective heat transfer coefficient in these fluids, in contrast to the observation in several conventional nanofluids containing solid nanoparticles.
Evaporation and Condensation on Two-Tier Superhydrophobic Surfaces
Authors: Chen Chuan-Hua , Cai Qingjun , Chen Chung-Lung
Published: June 2009

Superhydrophobic surfaces exhibit large contact angle and small hysteresis which promote liquid transport and enhance heat transfer. Here, liquid-vapor phase change behavior is reported on superhydrophobic surfaces with short carbon nanotubes deposited on micromachined posts, a two-tier texture mimicking the surface structure of lotus leaves. Compared to one-tier microtexture which energetically favors the Wenzel state, the two-tier texture with nanoscale roughness favors the Cassie state, the desired superhydrophobic state. During droplet evaporation, the two-tier texture delays the transition from Cassie to Wenzel state. Using two-tier texture with hexadeconethiol coating, continuous dropwise condensation was demonstrated for the first time on engineered superhydrophobic surfaces.
Nanofluid Generation Using Multi-Beam Laser Ablation Technique
Authors: Phuoc Tran X. , Soong Yee , Chyu Minking K.
Published: June 2009

Multi-beam laser ablation in liquid was used to synthesize nanofluids of silver, Zinc, and aluminum in liquids. In our experiments, two single-mode, Q-switched Nd-Yag lasers operating at 1064 nm, pulse duration of 5.5 ns and 10 Hz rep rate were used. Our results have shown that both laser intensities and multi-beam ablation can increase the ablation rate and promote reduction of the particle sizes and particle size distribution. For silver, we have generated various samples of nanofluids with particles of sizes mainly in the range of 20 to 30 nm. These samples were stable for several months without the need of using dispersants or surfactants. However, for aluminum, the generated fluids were not stable and significant amount of solid precipitates were observed in the stock solutions. The size distribution was from about 5 nm to 300 nm indicating that the particle agglomerated and large distribution in sizes. Typical results from TEM analysis indicated that, for silver-water nanofluids, Ag nanoparticles were fcc single crystals. For aluminum, the particles had different shapes and sizes. These shapes were triangular, rectangular, and fibrous.
Three Dimensional Numerical Analysis of Laminar Slip-Flow Heat Transfer in Rectangular Microchannels
Authors: Madhawa Hettiarachchi H. D. , Golubovic Mihajlo , Worek William M.
Published: June 2009

Slip-flow and heat transfer in rectangular microchannels are studied numerically for constant wall temperature (T) and constant wall heat flux (H2) boundary conditions under thermally developing flow. Navier-Stokes and energy equations with velocity slip and temperature jump at the boundary are solved using finite volume method in a three dimensional cartesian coordinate system. A modified convection-diffusion coefficient at the wall-fluid interface is defined to incorporate the temperature-jump boundary condition. Validity of the numerical simulation procedure is stabilized. The effect of rarefaction on heat transfer in the entrance region is analyzed in detail. The velocity slip has an increasing effect on the Nusselt (Nu) number whereas temperature jump has a decreasing effect, and the combined effect could result increase or decrease in the Nu number. For the range of parameters considered, there could be high as 15% increase or low as 50% decrease in fully developed Nu is plausible for T thermal boundary condition while it could be high as 20% or low as 35% for H2 thermal boundary condition.
Development of a High Performance Vapor Chamber for High Heat Flux Applications
Authors: Zhao Yuan , Chen Chung-Lung
Published: June 2009

This paper introduces a high performance vapor chamber heat spreader with a novel bi-dispersed wick structure. The main wick structure is a sintered porous network in a latticed pattern, which contains not only small pores to transport liquid by capillary forces, but also many slots to provide large passages to vent vapor from heated surfaces. The copper particles have a diameter of approximately 50 μm; they produce an effective pore radius of approximately 13 μm after sintering. The slots have a typical width of approximately 500 μm. Unlike traditional bi-dispersed wick structures, the latticed wick structures provide undisrupted liquid delivery passages and vapor escape channels and thus greatly improve the heat transfer performance. Preliminary experimental tests were conducted and the results were analyzed. It was shown by the experiments that vapor chamber heat spreaders with the latticed wicks present three times improvement on heat spreading performance, comparing with a solid copper heat spreader, and much improved capacity to handle hot spots with local heat fluxes exceeding 300 W/cm2, which will have great impacts on extending heat pipe technology from traditional low to medium heat fluxes to high heat flux applications.
Investigation of Micro Droplet Formation in a T-Shaped Junction Using Multicolor Confocal Micro PIV
Authors: Oishi Masamichi , Kinoshita Haruyuki , Oshima Marie , Fujii Teruo
Published: June 2009

This paper aims to investigate a mechanism of microdroplet formation using “multicolor confocal micro particle image velocimetry (PIV)” technique. The present system can measure dynamical behavior of multiphase flow separately and simultaneously. It also enables to identify the interactions between two immiscible fluids. We have applied this system to measure the water droplet formation at a micro T-shaped junction. We have also succeeded in dispersing fluorescent tracer particles into both phases. The interaction between the internal flow of to-be-dispersed water phase and of continuous oil phase is measured as a liquid-liquid multiphase flow. As a result of PIV measurement and interfacial geometry scanning, the relationship between flow structure of each fluid and interfacial geometry is clarified. It indicates that the gap between the tip of discontinuous flow and capillary wall, and interface area play an important role in the flow structure and shear stress on the interface.
Thermal Conductivity of Silicon Nanowire by Nonequilibrium Molecular Dynamics Simulations
Authors: Wang Shuai-Chuang , Liang Xin-Gang , Xu Xiang-Hua
Published: June 2009

The thermal conductivity of the silicon nanowire was calculated using nonequilibrium molecular dynamics method. The dependence of thermal conductivity on the wire length, cross-sectional area, and temperature was investigated. The Stillinger-Weber potential model and the Nose-Hoover thermostat were used. The surfaces at the wire ends were set free boundary conditions and potential boundaries in other directions. The cross-sectional area range of the nanowires under research is from about 5 nm2 to 19 nm2 and the length range is from about 6 nm to 54 nm. The results agree well with experimental results. The reciprocal of thermal conductivity was found to be linear with that of nanowire length. And our results quantitatively showed that decreasing the cross-sectional area can reduce the phonon mean free path of the nanowire.
Enhanced Natural Convective Heat Transfer of CNT-Ethylene Glycol-Water Suspensions
Authors: Witharana Sanjeeva , Cheng Haisheng , Ding Yulong
Published: June 2009

This paper presents an experimental study on the rheology and steady state natural convective heat transfer of suspensions of Carbon nanotubes (CNT) in the Water - Ethylene Glycol (WEG) base liquid, heated in a cylindrical cavity. Two series of experiment were performed in two orientations of the central axis of the cavity; vertical, and, horizontal. In vertical axis experiments, the heat was supplied from the bottom. The cylindrical cavity was made out of Aluminium, 10mm in height and 240mm in diameter. The heat input was 215W/m2. The CNTs used had an aspect ratio of ∼150. There were six suspensions investigated in either series of tests; CNT 0.1wt%, and EG 0, 10, 25, 50, 75 & 100wt%. It was found that the vertical axis orientation deteriorates heat transfer in all cases. However for horizontal orientation, there is a spectacular enhancement of up to 83% depending upon the EG concentration. The results also show that WEG-CNT suspension demonstrates non-Newtonian behaviour, which augments with increasing EG concentration.
A Comparison of the Void Fraction Correlations of R134A During Condensation in Vertical Downward Laminar Flow in a Smooth and Microfin Tube
Authors: Dalkilic Ahmet Selim , Laohalertdecha Suriyan , Wongwises Somchai
Published: June 2009

Void fractions are determined in vertical downward annular two-phase flow of R134a inside a 7 mm i.d. smooth and microfin tube. The experiments are done at average qualities ranging between 0.67–0.99. The mass fluxes are around 29 kg/m2s. The pressures are between 0.77–0.9 MPa. The experimental setup is explained elaborately. Comparisons between the void fraction determined from 35 void fraction correlations are done. According to the use of various horizontal and vertical annular flow void fraction models together with the present experimental condensation heat transfer data, similar void fraction results were obtained mostly for the microfin and smooth tube. Effect of void fraction alteration on the momentum pressure drop is also presented.
Finite Element Modeling of Multi-Scale Thermal Contact Resistance
Authors: Thompson M. K.
Published: June 2009

Many traditional macro scale finite element models of thermal contact systems have incorporated the effect of micro scale surface topography by applying a constant value of thermal contact conductance (TCC) per unit area to the regions in contact. However, it has been very difficult to determine an appropriate TCC value for a given system and analysts typically had to rely on experimental data or values from the literature. This work presents a method for predicting micro scale TCC per unit area by incorporating micro scale surface roughness in a multi-scale iterative thermal/structural finite element contact model. The resulting TCC value is then used in a macro scale thermal/structural contact model with apparent surface form to predict the thermal contact resistance and overall thermal resistance for a commercial power electronics module.
Analysis of the Total Heat Transfer in an Evaporating Thin Film
Authors: Wang Hao , Garimella Suresh V. , Murthy Jayathi Y.
Published: June 2009

When a liquid wets a solid wall, the extended meniscus may be divided into three regions: a non-evaporating region where liquid is adsorbed on the wall; a thin-film region where effects of long-range molecular forces (disjoining pressure) are felt; and an intrinsic meniscus region where capillary forces dominate. In this work, a simplified model based on the augmented Young-Laplace equation is developed and an analytical solution is obtained to more easily evaluate the total heat transfer in the thin-film region. The results are consistent with previously published numerical solutions. The present work is valid for a much wider range of fluid thermal conductivity than a previous analytical solution by Schonberg et al, which is only applicable for fluids with very low conductivity.
Boiling and Condensation in Microchannels
Authors: Cheng Ping , Wang Guodong , Quan Xiaojun
Published: June 2009

The characteristics of boiling of water and condensation of steam in a microchannel under heating or cooling conditions are discussed in this paper. Stable and unstable boiling modes occur in a microchannel, depending on the nucleated bubble size in the microchannel. Stable boiling mode with constant temperature variations exists when the size of the nucleated bubble is less than that of the microchannel diameter, while unstable boiling mode exists when the size of the bubble is greater than the microchannel diameter. The latter is owing to the fact that when a bubble grows to the size of the microchannel, it will expand in both upstream and downstream directions. Subsequently, the reversed flow of vapor bubble is swept downstream by the incoming subcooled liquid, leading to large cyclic fluctuations of temperature and pressure. The amplitude and frequency of these fluctuations depend greatly on the inlet/outlet configurations and the exit vapor quality. By fabricating an inlet restriction on each microchannel, the reversed flow of vapor can be suppressed, resulting in a stable flow boiling mode. Boiling heat transfer coefficient and pressure drop in a microchannel under stable flow boiling conditions are obtained. These data at high vapor qualities are found to be substantially different from the correlations obtained for flow boiling in macrochannels. For condensation in a microchannel, mist flow, annular flow, injection flow, slug/bubbly flow exist depending on mass flux, condensation heat flux, and the location in the microchannel. The occurrence of the injection flow is owing to the instability of the liquid/vapor interface because the surface tension effect is predominant in microchannels. The location, at which the injection flow occurs, depends on the mass flux and the cooling rate of steam. Increase in steam mass flux, decrease in cooling rate and the microchannel diameter tend to enhance instability of the condensate film on the wall, resulting in occurrence of the injection flow further toward the outlet with an increase in occurrence frequency. At low mass fluxes, the pressure drop obtained for condensation in microchannels is substantially different from the correlation equations for macrochannels because of different flow patterns.
Keeping Up With Growth by Recommitting to a Long-Term Waste-to-Energy Future
Authors: Schauer Raymond H.
Published: June 2009

The Solid Waste Authority of Palm Beach County (Authority) has owned the North County Resources Recovery Facility (NCRRF) since 1989, producing clean, economical and renewable energy from refuse derived fuel while preserving precious landfill space. As with any facility as it approaches the end of its first 20-year operating term, the Authority found it necessary to initiate a comprehensive refurbishment to ensure its continued effective operations. The operating agreement between the Authority and the Palm Beach Resource Recovery Corporation (PBRRC), a subsidiary of Babcock & Wilcox (B&W), is set to expire concurrently with the end of the this 20-year term. The Authority acknowledged that PBRRC has unparalleled institutional knowledge of the NCRRF and, as such, took the opportunity to renegotiate its operating agreement with PBRRC for an additional 20-year term. The Authority was also able to build into the new operating agreement conditions for PBRRC to provide assistance to a third party design-builder performing the refurbishment. Additionally, understanding that B&W produced many of the key combustion unit components of the original NCRRF construction, the Authority worked into the new agreement terms for B&W to provide several essential components for the refurbishment that will be installed by the design-builder. When the refurbishment is completed in 2011, the Authority will still only have disposal capacity through 2021 with its existing landfill. To be able to keep up with rapid growth in Palm Beach County, the Authority has initiated the due diligence phase for the development of a new mass burn waste-to-energy facility and landfill that will expand the disposal capacity of the Authority’s system for more than 100 years.
A Case Study of the Selective Catalytic Reduction (SCR) System at the Algonquin Power Energy-From-Waste Facility
Authors: Hatton Janice , Bulionis Peter
Published: June 2009

The Algonquin Power Energy-From-Waste (APEFW) facility is located in the suburban Toronto, Ontario city of Brampton. It receives approximately 140,000 metric tonnes (154,000 tons) of MSW per year from the Region of Peel (Region) and approximately 10,000 metric tonnes (11,000 tons) per year of international airport waste from the area’s two international airports. The APEFW facility commenced initial operations in 1992 and included four, 91 tonne (100 ton) per day Consumat two stage incinerators with heat recovery boilers and a dual-train air pollution control (APC) system consisting of evaporative cooling towers, venturi reactors and fabric filter baghouses. The APEFW facility expanded its capacity in 2001 with the addition of a fifth 91 tonne (100 ton) per day modular incinerator and heat recovery boiler. One of the stipulations in the permitting process was that the entire expanded facility meet more stringent emission standards that included a significantly lower nitrogen oxides (NOx) emission rate. After a review of several available NOx control technologies, the APEFW facility chose to install a Selective Catalytic Reduction (SCR) system. While SCR systems are fairly common on EFW facilities in Europe, the APEFW facility is the only EFW facility in North America that currently operates with an SCR system and as such has gained valuable insight into the application and performance of this technology that is very relevant to the North American EFW industry. This paper discusses the operation and maintenance of the SCR system, compares pre- and post-SCR NOx emissions and presents capital and operating costs for the SCR including the cost per tonne of waste processed and the cost per tonne of NOx removed.
High Electrical Efficiency by Dividing the Combustion Products
Authors: Madsen Ole Hedegaard , Bo̸jer Martin , Jensen Peter Arendt , Dam-Johansen Kim
Published: June 2009

Energy recovery from waste is an efficient way to reduce emissions of greenhouse gas and other gaseous, liquid and solid pollutants and thereby to contribute to a sustainable development. Waste fired power plants are an important part of the European waste management system, and the demands made to modern waste fired power plant are very focused on high electrical output. Lately, Babcock & Wilcox Vo̸lund (BWV) and the CHEC research centre at the Technical University of Demnark has developed a new technology and received a world patent. The basic idea is to improve the electrical efficiency by increasing the steam data. Especially, increasing the steam temperature without the risk of superheater corrosion. The new concept is fully integrated in the boiler and from the outside the waste fired power plant has the same layout as the classic waste fired power plant. The goal is to achieve an increase between 50 °C to 100 °C in the superheated steam temperature and a total increase of electrical efficiency up to 30% without any influence on the normal operation. This paper presents the basic ideas that provide a basis for the patent. The core of the technology is a combination of a new furnace design and a new control system. At the moment, test results from an operating plant support the principal idea. Furthermore, the concept will be studied in the numerical laboratory where CFD simulation will be used to evaluate the technology and to determine the potential process improvements. The final improvement of electricity production has to be determined in the coming test period on a full scale installation, which is currently being planned.
Options and Strategies for Waste to Energy Facility Energy Sales in Deregulated Markets
Authors: Chesser Noel P.
Published: June 2009

Many US Municipal Waste to Energy (WTE) plants entered into long term electric sales contracts with their local utilities for the electricity generated. These legacy contracts will be expiring over the next few years. With the advent of electric deregulation, the energy markets are vastly different and WTEs now have many more options to optimize the value of the energy generated from their facilities. There are even some options available for WTE’s located in regulated markets. A well developed energy sales strategy and execution can make a significant difference in the value realized from the WTE energy generated. To understand the options available to WTE’s it is first helpful to have a basic understanding of the power markets. In markets that are deregulated, there exists two primary markets, the hourly market were prices are set by the regional independent system operator (ISO) such as PJM or NYISO and the forward markets which offer fix rates for energy delivered some time in the future. The hourly market prices are highly transparent (posted on ISO’s web site) and are based on the marginal cost of fuel used to meet the last increment of demand during that hour. In the Mid-Atlantic, New York and New England prices are typically driven by the price of natural gas and to a lesser extent fuel oil and coal. The forward markets are driven by counterparties who are willing to offer fixed prices in return for risk premiums added to the price to cover their price risk. Forward market pricing is not as transparent and requires knowledge of the market, knowledge and experience with the major buyers and sellers and multiple price bids. Options for WTEs facilities now include sales directly to the ISO, sales to wholesale buyers (generally 1–5 years), sales to local utilities and power authorities, sales directly to the local municipality and sales to large local commercial/industrial users of energy. The option selected should be consistent with a well defined energy sales strategy. The strategy should incorporate a price risk profile, budget and funding requirements/objectives, facility operating risk profile, credit risk, local considerations, and risk management timeframe. The mechanisms required to execute the above options vary and involve different approaches, contract structures, licenses, memberships, risks and rewards. There are qualified independent energy consultants that can assist WTEs in understanding the markets, developing energy sales strategies and execution thereof to help ensure the value of the energy generated is optimized.
An Investigation of the Thermal Degradation Mechanisms of a Waste Tire Through Chemical Analysis Including Hydrocarbons, Benzene Derivatives, and Polycyclic Aromatic Hydrocarbons (PAHs) at High Temperature
Authors: Castaldi Marco J. , Kwon Eilhann
Published: June 2009

Previous work has focused on a series of fundamental Thermal Gravimetric Analysis (TGA) studies using representative atmospheres found in Waste-to-Energy (WtE) boilers. Those studies were done for waste tires and their major constituents, such as Styrene-Butadiene Copolymer (SBR) and Poly-Isoprene (IR). The outcome has been the elucidation of the likely mechanism responsible for initial decomposition, final product and byproduct formation. To extend that understanding to a more practical level, a flow through apparatus has been used to test waste tire samples in the temperature range of 500°C–800°C. A chemical analysis in this temperature range has been performed to compare the thermal degradation mechanism and air pollutant generation in low temperature regimes. The release of chemicals from a tubular quartz reactor containing a tire sample has been determined experimentally using a GC/MS. Significant Volatile Organic Carbons (VOCs) including benzene derivatives, PAHs, and Hetero-N containing PAHs were observed. This study identifies and quantifies the concentration levels of various hazardous air pollutants, and provides new data for the overall development and validation of detailed reaction mechanisms that can describe the thermal degradation of waste tires. This information will enable the development of mitigation strategies that can address those levels of pollutant species.
The Effects of Varied Hydrogen Chloride Gas Concentrations on Corrosion Rates of Commercial Tube Alloys Under Simulated Environment of WTE Facilities
Authors: Lee Shang-Hsiu , Castaldi Marco J.
Published: June 2009

In order to clarify the effects of HCl concentrations on corrosion rates of commercial tubing in Waste-to-Energy (WTE) boilers, a corrosion test was made by altering the HCl concentration from 0 to 1000ppm, together with simulated flue gas composition. Three commercial tubing SA178A, SA213 T11 and NSSER-4 samples were investigated under a well controlled thermal gradient where the gas temperature was at 700°C and metal temperatures ranged from 480 to 580°C. The duration of each test was 100 hours. The posttest analyses included observations of surface morphology and elementary composition analysis of corrosion products by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The corrosion rates were acquired by measuring the mass loss of samples after the test. The results showed that the addition of HCl to the flue gas increased the corrosion rates of test samples, but the relation between the HCl concentration and corrosion rate was not linear. The HCl effects on corrosion rates were more prominent when its concentration changed from 0 to 500ppm. In addition, the HCl effects were promoted by the increase of metal temperature in particular when metal temperature was over 560°C.
Recycling of Municipal Solid Waste Ash Through an Innovative Technology to Produce Commercial Zeolite Material of High Cation Exchange Capacity
Authors: Sallam Maysson , Carnahan Robert P. , Zayed Abla , Sunol Sermin
Published: June 2009

Municipal solid waste ash (MSW ash) samples, obtained from a local incinerator in Florida, were converted via a chemical process into zeolite material. The conversion process was performed by applying a two step treatment. The ash samples were fused at 550°C under alkaline conditions and then the fused ash samples were treated hydro-thermally at 60 °C and 100°C for different periods. This innovative technology involves adjusting the SiO2/Al2O3 ratio of the ash from 13.9 to 2.5 by adding sodium aluminates and by using a solid to liquid ratio of 10. The fusion step formed sodium silicate and sodium aluminum silicate phases. These phases acted as precursors to the formation of zeolite A. Zeolite A was successfully formed within the ash matrix when samples were fused and SiO2/Al2O3 was adjusted. The maximum cation exchange capacity, CEC, was measured by using ammonium acetate solution. The CEC of the produced zeolitic ash material has increased significantly from 17 meq/100g for non-treated ash up to 212 meq/100g for the treated ash. The cation exchange capacity of the produced zeolite ash material is close to that available from commercial zeolite materials which have a CEC of 245meq/100g. Zeolite A formation within the ash matrix increased the potential of using the ash as an adsorbent for industrial and environmental applications including ammonia removal from waste water or any other similar application that involves cation exchange.
Unique Elements of the Olmsted County Facility Expansion
Authors: Clark Matt
Published: June 2009

Olmsted County is currently expanding their existing waste-to-energy facility in Rochester, Minnesota to add a third mass burn waste combustor. The new unit will have a capacity of 200 TPD, effectively doubling the size of the existing capacity. This paper will discuss some of the unique aspects of this project and review the current status. Some of the interesting and unique features to be discussed include: 1. Environmental Permitting – The county decided to do a voluntary EIS. 2. Project approach – The county is using a Construction Manager at Risk approach for construction of the facility. 3. Engineering – The engineering scope includes several separate procurements of major equipment packages, balance of plant design and several auxiliary projects related to the ‘utility’ system. 4. Operator Collaboration – Olmsted County is one of a few public owners that operate their facility. Their knowledge of the existing facility and of operating a mass burn facility has been used extensively in the planning and design of the new unit.
Life Cycle Comparison of Two Options for MSW Management in Puerto Rico: Thermal Treatment vs. Modern Landfilling
Authors: Balaguer-Da´tiz Giselle , Krishnan Nikhil
Published: June 2009

The management of municipal solid wastes (MSW) in Puerto Rico is becoming increasingly challenging. In recent years, several of the older landfills have closed due to lack of compliance with federal landfill requirements. Puerto Rico is an island community and there is limited space for construction of new landfills. Furthermore, Puerto Rico residents generate more waste per capita than people living on the continental US. Thermal treatment, or waste to energy (WTE) technologies are therefore a promising option for MSW management. It is critical to consider environmental impacts when making decisions related to MSW management. In this paper we quantify and compare the environmental implications of thermal treatment of MSW with modern landfilling for Puerto Rico from a life cycle perspective. The Caguas municipality is currently considering developing a thermal treatment plant. We compare this to an expansion of a landfill site in the Humacao municipality, which currently receives waste from Caguas. The scope of our analysis includes a broad suite of activities associated with management of MSW. We include: (i) the transportation of MSW; (ii) the impacts of managing waste (e.g., landfill gas emissions and potential aqueous run-off with landfills; air emissions of metals, dioxins and greenhouse gases) and (iii) the implications of energy and materials offsets from the waste management process (e.g., conversion of landfill gas to electricity, electricity produced in thermal treatment, and materials recovered from thermal treatment ash). We developed life cycle inventory models for different waste management processes, incorporating information from a wide range of sources — including peer reviewed life cycle inventory databases, the body of literature on environmental impact of waste management, and site-specific factors for Puerto Rico (e.g. waste composition, rainfall patterns, electricity mix). We managed uncertainty in data and models by constructing different scenarios for both technologies based on realistic ranges of emission factors. The results show that thermal treatment of the unrecyclable part of the waste stream is the preferred option for waste management when compared to modern landfilling. Furthermore, Eco-indicator 99 method is used to investigate the human health, ecosystem quality and resource use impact categories.
A Fourth Generation WTE Facility Designed for Energy and Materials Recovery: The Amsterdam AEB Waste-Fired Power Plant
Authors: de Waart Hendrikus A. A. M. , van Berlo Marcel
Published: June 2009

This paper describes a fourth generation WTE facility, the Waste-Fired Power Plant (WFPP®) owned and operated by the City of Amsterdam. This plant is designed with the Best Available Technologies (BAT) to achieve the lowest possible emissions to air, water and soil, thereby creating the lowest possible nuisance levels to neighboring residents, offices and industries. The plant is also designed to maximize electricity production, and to recycle and recover the maximum amount of materials which include ferrous and non-ferrous metals, sand and granulate to produce building products and gypsum and salt from fluegas. In addition the paper describes the design features applied to achieve the world’s best energy efficiency and includes a discussion on the life cycle economic advantages of BAT applications and the positive effect of BAT on Green House Gas emissions.
Plasma Gasification: A Proven Technology
Authors: Dighe Shyam V.
Published: June 2009

Plasma gasification is an efficient and environmentally responsible form of thermal treatment of wastes. In the plasma gasification process, extremely high temperature gases are used to break down the molecular structure of complex carboncontaining materials — such as municipal solid waste (MSW), tires, hazardous waste and sewage sludge — and convert them into synthesis gas (syngas) containing hydrogen and carbon monoxide that can be used to generate power or other sustainable sources of energy. Gasification occurs in an oxygen starved environment so the waste is gasified, not incinerated.
Operational Training: The Role of Simulators in Plant Operations
Authors: Boisse Roger
Published: June 2009

It’s 4 a.m. and the crane operator is a little overzealous, which is starting to show inside the boiler. The bad news is that by the way he’s feeding the chute, it’s only a matter of time until the control room operator loses control of the combustion process, the temperature drops and they’ll face the consequences. The good news, this is a drill. It’s only a drill. And the situation they’re facing is only a simulation. As part of its core training program for plant operating personnel, Wheelabrator Technologies relies on a special computer simulator, licensed from Von Roll Inova, that’s as close to real life as flight simulators are to flying. Just as there’s no airplane to damage as the pilot trains, there’s no boiler. The simulator runs a sophisticated computer program that is identical to the control rooms of the waste-to-energy facilities Wheelabrator operates. It provides users with real-life operating challenges—the good, the bad, and the ugly. Operating scenarios are simulated to exacting standards to provide plant personnel—the plant managers, control room operators, and crane operators—with the ability to respond appropriately to any situation. The simulator allows users to adjust any aspect of operation, from over- or under-fire air to moisture in the virtual trash being fed into the boilers. The process encourages teamwork and allows users to experience situations that could damage property, injure employees or harm the environment. The benefits of the ability to replicate upset and emergency, situations are clear: employees are ready for anything and the instruction helps prevent what would otherwise be downtime or expensive mistakes. The simulator process only works, however, because it’s part of Wheelabrator’s overall training process. The simulator enhances “textbook” instruction in theory and handson qualification checks that all operators receive on a regular basis. It allows them to apply the knowledge they gain from the instruction in the controlled atmosphere of the simulator. Roger Boisse, Senior Manager, Operations Projects with Wheelabrator Technologies, will explain the core operations training program and demonstrate the combustion simulator developed by Von Roll Inova, showing how it can be effective in providing operators with hands-on, and risk-free, experience.
Art of the Deal: Building WTE in the 21st Century
Authors: Schwartz Mark , Disney Cal
Published: June 2009

The nation’s first successful commercial waste-to-energy facility went on-line in 1975 and the industry has accumulated a three-decade long track record—operating safely, improving efficiencies, and meeting new, tougher environmental standards. The industry has matured and has learned from operating experience. But as the industry faces a revival, have we also learned to improve on the art of the deal? In the past, the standard lump sum RFP approach forced project sponsors and vendors into a type of Russian roulette—one-sided gamesmanship that opened one or both sides to unreasonable risk with willing partners in the construction and financial community. On today’s financial and financial risk playing field, though, Wheelabrator believes that the road to prosperity—for sponsor and vendor—is found in above-board open book negotiations. It’s a process designed to reduce economic risk and provides a more realistic picture of the actual cost of the project once it’s in the ground and operating. Mark Schwartz, Senior Manager of Business Development for Wheelabrator Technologies, and Cal Disney, Vice President of Whiting-Turner, will review the pitfalls of the past and discuss how the process can be improved when all parties participate in the design, permitting and construction oversight of a facility. They will discuss how the process can lead to contracts with fixed costs, lower capital costs, minimal risks and a public private partnership that gets the most value for taxpayer dollars.
Waste-to-Energy and the Solid Waste Management Hierarchy
Authors: O’Brien Jeremy K.
Published: June 2009

The SWANA Applied Research Foundation’s (ARF) Waste-to-Energy (WTE) Group identified the issue of the waste-to-energy’s ranking in the solid waste management hierarchy as one of high importance to the group.
Waste-to-Energy in the Context of Global Warming
Authors: Chromec Peter R. , Ferraro Francis A.
Published: June 2009

In December 2007 the United Nations Framework Convention on Climate Change (UNFCCC) took place in Bali. It was based on the IPCC report no. 4 presented in Barcelona on November 2007. The messages are briefly: • Warming of the climate system is unequivocal; • Global greenhouse gas (GHG) emissions due to human activities have grown since pre-industrial times; • Continued GHG emissions at or above current rates would cause further warming and induce many changes in the global climate system during the 21st century that would very likely be larger than those observed during the 20th century; • Key mitigation technologies in the waste sector: Landfill Gas (LFG) methane recovery; waste incineration with energy recovery; composting of organic waste; controlled waste water treatment; recycling and waste minimisation; biocovers and biofilters to optimise methane oxidation. The above by the IPCC proposed mitigation technologies for the waste sector can be categorized regarding specific waste treatment scenarios and their efficiency expressed in kg CO2 equivalent emitted per ton of waste. • Landfill w/o LFG recovery 1850 kg CO2-eq; • Landfill with LFG recovery 250–775 kg CO2-eq; • Energy-from-Waste plant −1000..−100 kg CO2-eq. With a population of little over 300 million people and a per capita municipal waste generation rate of 760 kg/person.year, the total waste generated in the USA is about 230 million Mg/year (OECD). With the treatment scenarios discussed above, the following can be stated: • If all wastes were landfilled waste disposal would correspond to 425 million tons of CO2 equivalents. • If all wastes were incinerated in Energy-from-Waste (EfW) plants, the emissions could be reduced by about 500 million tons of CO2 equivalents (about 9% of today’s US CO2 output) and make the waste management sector a GHG emissions sink. • The total electricity generated from EfW plants could be as high as 15,000 MW replacing about 50 standard 300 MW power plant units. To an average US 4 person household about 3 t/year of municipal solid wastes can be allocated, corresponding to an annual difference between landfilling without LFG recovery and EfW treatment of about 6.9 Mg CO2-eq /year. If this household wanted to achieve the same reduction of CO2 equivalent emissions by other means than having these wastes burnt in a modern EfW plant, they have the following options: • Remove one automobile from use (EPA: 6.0 Mg CO2-eq /year); • Cut household electricity consumption by 80% (EIA: 7.8 Mg CO2-eq /year). The European parliament commission has proposed to reduce CO2 emissions in Europe to 20–30% below 1990 levels. In comparison with Europe, annual GHG emissions (CO2-eq/person year) in the U.S. today are on a level about double that of the Europe. In order to achieve a similar reduction in the U.S., significant efforts have to be done on all energy fronts. Energy-from-Waste (EfW) is one of them, which at the same time solves a space and pollution problem and does not leave these issues to future generations.
Plunge Instability of a Square Bluff Body in Crossflow
Authors: Tomko Robert P. , Ibrahim Baky B.
Published: June 2009

Flow-induced vibration tests were performed on a beam with a square cross section. The test article was induced into a plunge mode self-excited vibration by forcing air across the beam while it was suspended by leaf springs. The natural frequency and the damping were varied during these tests to alter the variables that contribute the onset of flow-induced vibration. Additionally, cantilevered beams were tested in the same wind tunnel and results proved to be consistent with results from the leaf spring supported beam. The slope of the vertical force coefficient was determined from this testing; this coefficient was determined to be approximately unity, which was roughly 1/3 of the value found in other published data.
Noise Levels During College Football Games and Associated Effects on Players and Fans
Authors: Barnard Andrew R. , Gillett Philip , Idrisi Kamal , Hambric Stephen A. , Johnson Marty
Published: June 2009

Crowd noise levels in large stadiums are often discussed in the press and by the casual stadium patron; however, there has been little scientific evaluation of these levels and their corresponding effects. An effort was undertaken at Penn State University to measure noise on the field at Beaver Stadium (State College, PA: capacity 107,282) during a PSU football game. The two-fold purpose of these measurements was to evaluate the noise levels with respect to how they affect the game and make real-time, calibrated recordings for future use in the football team’s indoor practice facility. Measurements were taken on the field level using sound levels meters and DAT recorders throughout the PSU vs. Ohio State University football game on 27 October 2007. As a point of comparison, similar measurements were conducted by a team of researchers from Virginia Tech during the VT vs. University of Miami game on 17 November 2007 at Lane Stadium (Blacksburg, VA: capacity 66,233). The crowd noise levels are compared between the two stadiums taking into account the circumstances of the two games, time of day, and design of the stadiums. The levels on the field are evaluated in terms of speech intelligibility, i.e. the ability of the players to communicate with each other. In addition, a hearing loss safety assessment for both fans and players is presented.
The Influence of Flow Instability on the Lock-In of Distributed Elastic Resonators
Authors: Cody Kristin Lai-Fook , Hambric Stephen A. , Pollack Martin L. , Jonson Michael L.
Published: June 2009

Lock-in occurs between many different types of flow instabilities and structural-acoustic resonators. Factors that describe the coupling between the fluid and structure have been defined for low flow Mach numbers. This paper discusses how different flow instabilities influence lock-in experimentally and analytically. A key concept to the lock-in process is the relative source generation versus dissipation. The type of fluid instability source dominates the generation component of the process, so a comparison between a cavity shear layer instability with a relatively stronger source, for example wake vortex shedding from a bluff body, will be described as a coupling factor. In the fluid-elastic cavity lock-in case, the shear layer instability produced by flow over a cavity couples to the elastic structure containing the cavity. In this study, this type of lock-in was not achieved experimentally. A stronger source, vortex shedding from a bluff body however, is shown experimentally to locks into the same resonator. This study shows that fluid-elastic cavity lock-in is unlikely to occur given the critical level of damping that exists for a submerged structure and the relatively weak source strength that a cavity produces. Also in this paper, a unified theory is presented based on describing functions, a nonlinear control theory used to predict limit cycles of oscillation, where a self-sustaining oscillation or lock-in is possible. The describing function models capture the primary characteristics of the instability mechanisms, are consistent with Strouhal frequency concepts, capture damping, and are consistent with mass-damping concepts from wake oscillator theory. This study shows a strong consistency between the analytical models and experimental results.