bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimized Ammonia Injection for Power Plant SCR Systems
Authors: Buzanowski Mark A. , Fadda Dani
Published: May 2009

Ammonia injection grid (AIG) is used to introduce vaporized ammonia (NH3) into an exhaust gas stream for nitrous oxide (NOx) reduction in selective catalytic reduction (SCR) systems. Computational and experimental studies on the AIG resulted in significant improvements in the turbulence mixing between the injected ammonia and the exhaust gas. Improved mixing is instrumental to maximize catalyst performance, extend catalyst life time, minimize catalyst volume, decrease system pressure drop, minimize reagent use and ammonia slip, minimize the overall size of the SCR system, and minimize risks associated with designing the SCR system. It is found that an AIG with a turbulence-generating edge dramatically increases the mixing efficiency and, therefore, reduces the mixing distance required to obtain acceptable distributions of the NH3 to NOx ratio. Results indicate over 50% reduction of the required mixing distance due to the turbulence generating edge. This work summarizes the obtained results from computational CFD simulations for two-dimensional and three-dimensional models, however the proposed arrangement of the injection grid has been successfully tested in laboratory experiments and applied to several commercial power generating systems. The commercial performance results will be reported in the subsequent publications.
A Revolution in Conveyor Transfer Technology: InteliFlo™ Adjustable Skirtless Transfer System
Authors: Schwartz Jason B.
Published: May 2009

A difficult balance must be maintained between new asset investment costs, operating and maintenance costs, and maintaining an acceptable level of risk. Various capital investment and budget allocation strategies have been implemented to prioritize asset allocation. To maintain a competitive edge in plant operations, these sound fundamentals must also be applied to all areas of a plant, including the coal yard. By ignoring even “small” deficiencies, operations are exposed to wasted budget dollars and manpower assets and well as to potentially large risks.
Optimal Design for Damper of Long Blade in Steam Turbine Based on Dynamic Analysis
Authors: Xie Yonghui , Zhang Di
Published: May 2009

Adding damped structure can decrease dynamic stress of blade and avoid blade fatigue failure from forced vibration. Based on the structural feature of long blade with friction damper, the numerical model for dynamic analysis of damped blade in steam turbine has been developed. The blade was described by twisted beam element, the usual space beam element was adopted to analyze the frame of damper, and the slip motion between rubbing surface was modeled by a damping connector. The following matrices which are necessary for finite element analysis were obtained: the stiffness matrix, mass matrix and damping matrix of finite element for blade and damper, the stiffness matrix and damping matrix of damping connector. Then the gross finite element motion equation of the blade was got. Meanwhile, harmonic wave propagation method was adopted to improve calculation efficiency. The comparison of calculation results and experimental data of a 360mm blade shows good agreement. The dynamic characteristic of a last stage long blade in steam turbine with damper was analyzed in detail, its responses with different thickness shroud and gap between shrouds were investigated in detail too, then the optimal structure of damped shroud was obtained, the comparison for response between damped blade and freestanding blade shows the maximum response of blade with optimal damper is 42.4% of that of freestanding blade. At last, a tie wire was added to the damped blade, numerical result shows it can decrease blade response further.
A Combined Numerical Model and Optimization for Low Pressure Exhaust System in Steam Turbine
Authors: Fan Tao , Xie Yonghui , Zhang Di , Sun Bi
Published: May 2009

Computational fluid dynamics is widely used in the aerodynamic performance analysis of the low pressure exhaust system (LPES) which consists of the exhaust hood and condenser neck. However, most of the former studies analyzed the exhaust system separately without considering the effect on flow field from the last stage. In order to get the detailed information of flow field in LPES of steam turbines and reduce energy loss, a numerical model includes condenser neck, exhaust hood and last stage was constructed. This model can describe the effect of unsymmetrical inlet flow on the aerodynamic performance of LPES, so the effect of the inhomogeneous flow from the last stage was taken into account. The Reynolds averaged N-S equations with RNG k-ε turbulence model were adopted to analyze the flow field in the exhaust system considering the interaction between the exhaust system and the last stage, the mixing plane approach was used. The combined model can provide more reasonable numerical results of LPES, it shows that the inhomogeneous flow from the last stage is one of the main reasons leading to flow separation in diffuser. The influence of inner low pressure heater and the diffuse function of the condenser neck structure are the main reasons for the nonuniform velocity distribution of the flow field at the LPES outlet. Furthermore, based on the numerical results, an optimal LPES which has better aerodynamic performance and more reasonable flow is obtained. The optimal structure has low steam resistance and low exhaust pressure, so it can increase the efficiency of turbine.
South Texas Project Nuclear Power Plant Unit 1 Condenser: Scale Deposit Removal From 96,234 Condenser Tubes
Authors: Saxon George , Moye William
Published: May 2009

South Texas Project (STP) Nuclear Power Plant was commissioned for operation in 1988. There are two units, Unit 1 and Unit 2, similar in design and capacity. Unit 1 is base loaded and produces 1,250 megawatts of power. There are 96,234 titanium condenser tubes, size 3/4” O.D. by 22 BWG in the multi-stage condenser. The tubes in the condenser were known to be fouled with calcium carbonate; however the extent of the fouling was unknown prior to the outage. The last effective cleaning on the Unit 1 condenser had been conducted five years ago in 2001 and only thin calcium deposits were noted at that time. It is well known that fouling of the condenser can have significant impact on unit operations: It increases unit heat rate and it can also limit unit generation capacity. However, due to the size and capacity of a condenser, and the heat transfer characteristics of a deposit type, fouling may go unrecognized until the deposition rate reaches an advanced level. As was the case at the South Texas Project Nuclear Power Plant in Wadsworth, Texas, where scale build up in the condenser tubes had not only developed, hardened, and thickened over time, but had also rendered many of the tubes completely blocked and useless. The tenacious scale, when combined with the large size of the condenser, made returning the condenser to its new and clean condition an extremely challenging project. A comprehensive cleaning project was planned and executed in September, 2006 cleaning all 96,234 titanium condenser tubes utilizing innovative scale cutting technology and mechanical scrapers. The completion of the project resulted in virtually all tubes being opened, clean, and available for service. This paper will acquaint you with the project from its conception to fruition and report the outcome.
Combined Turbine Equipment Performance
Authors: Butler Anthony E. , Nanjappa Jagadish
Published: May 2009

“Combined Turbine Equipment Performance” represents the combined performance of the Gas Turbine-Generator(s) and the Steam Turbine-Generator(s), while disregarding or holding the performance of the remaining equipment in the Power Plant at its design levels. The lack of established industry standards and methods addressing the manner in which combined turbine equipment performance should be determined has invited confusion and has created opportunities for technical errors to go undetected. This paper presents a method and the supporting theory by which the corrected performance of the turbine-generators within a combined cycle plant can be combined to gauge their combined performance levels for either contractual compliance or for diagnostic purposes. The Combined Turbine Equipment Performance methodology provided in this paper, allows the performance engineer to easily separate the performance contribution of each turbine generator from the overall plant performance. As such, this information becomes a powerful diagnostic tool in circumstances where a reconciliation of overall plant performance is desired. Individual (gas or steam) turbine performance can be determined by conducting a test in accordance with the respective test code (ASME PTC 22 or PTC 6.2). However, each of these test codes corrects the measured equipment performance to fundamentally different reference conditions. Where the gas turbine-generator measured performance is corrected primarily to ambient reference conditions, the steam turbine-generator measured performance is corrected to steam flows and other steam reference conditions. The simple mathematical addition of the corrected performance of each turbine ignores the well-known fact that the steam turbine-generator output in a combined cycle plant is impacted by the gas turbine exhaust conditions, in particular the gas turbine exhaust flow and temperature. The purpose of this paper is to provide a method for the determination of “Combined Turbine Equipment Performance”, review the supporting theory, highlight the assumptions, and develop useful transfer functions for some commonly used combined cycle plant configurations, and bound the uncertainty associated with the methodology.
Boiler Emission Control With Fuel Oil Emulsion (FOE) Technology
Authors: Houlihan Thomas
Published: May 2009

In the early twenty-first century, emphasis on fossil fuel emission reductions was focused on gaseous emissions. NOx emissions were recognized as precursors of smog and as such adversely affected the quality of life. Lately, emphasis on emission reductions has shifted to solid emissions. Particulates are recognized as health hazards that contribute to respiratory ailments. Fossil fuel combustion — so fundamental to the nation’s economy — unfortunately produces both emissions. Thus, the development of after-treatment technologies to treat fossil fuel combustion was pursued. Imposition of after-treatment technology proved costly from both application and maintenance aspects. In some instances, introduction of after-treatment technology caused a decrease in fuel efficiency. In view of the foregoing, it is important to note that there is a technology that REDUCES gaseous AND solid emissions of liquid fossil fuels. Furthermore, this technology can INCREASE fuel efficiency. The technology that can deliver this “triple-crown” of dual emission reduction and enhanced fuel efficiency is EMULSIFIED FUEL TECHNOLOGY (EFT). In this paper, we consider the constitution, production and characteristics of Emulsified Fuels. Then we consider their combustion and the environmental benefits that can accrue to their utilization. Finally, we consider past applications of EFT and the future markets for this intriguing technology.
Study on Two-Direction Suction Passage of Pumping Unit in Cooling System of Power Plant
Authors: Liu Chao , Feng Xusong , Cheng Li , Zhou Jiren , Liu Yan Jin Aihua
Published: May 2009

A special vertical pumping system was designed for cooling system of a power plant. In order to study flow pattern and hydraulic performances of vertical pumping system with bell inlet and symmetric volute outlet, especially the flow fields in the suction passage of pumping system, the incompressible N-S equations are solved by the finite volume method. Base on the k-ε model with Wall-Function Law, the SIMPLEC algorithm is applied for the solution of the discretization governing equation. Using multiple reference frames, solutions of the flow fields of whole vertical pumping system at a Reynolds number of more than 113,000 for flow in the pumping system are presented. The normal height of pumping system is put forward. The hydraulic performances of pumping system at the different operating points near to the Best Efficiency Point (BEP) were predicted. A model pumping system was designed to test the performances of the system and the measurements of velocity distribution in outlet section of the suction passage were taken. The velocity distribution of measurements and the velocity distribution of computation in outlet section of suction passage show an asymmetrical flow field even under the operation at BEP. In general the hydraulic condition of suction passage can meet the requirements of pump operation. The differences between the computational results and the measurements results are discussed.
State of the Art Steam Turbine Automation for Optimum Transient Operation Performance
Authors: Quinkertz Rainer , Gobrecht Edwin
Published: May 2009

The growing share of renewable energies in the power industry coupled with increased deregulation has led to the need for additional operating flexibility of steam turbine units in both Combined Cycle and Steam Power Plants. Siemens steam turbine engineering and controls presently have several solutions to address various operating requirements: - Use of an automatic step program to perform startups allows operating comfort and repeatability. - 3 start-up modes give the operator the flexibility to start quickly to meet demand or slowly to conserve turbine life. - Several options for lifetime management are available. These options range from a basic counter of equivalent operating hours to a detailed fatigue calculation. - Restarting capabilities have been improved to allow a faster response following a trip or shutdown. - In addition to control of speed, load and pressure, special control functions provide alternative work split modes during transient conditions. - Optimum steam temperatures are calculated by the steam turbine control system to achieve optimum startup performance. - Siemens steam turbines are also capable of load rejection to house load, some even to operation at full speed, no load. Several plants are already equipped with these solutions and have provided data showing they are operating with shorter start-up times and improved load rejection capabilities. Finally Siemens of course continues to pursue future development.
Application of Fuzzy Logic to Axial Compressor Performance Map Prediction
Authors: Ghorbanian Kaveh , Gholamrezaei Mohammad
Published: May 2009

The present paper applies fuzzy logic technique to predict the performance map of an axial compressor. This technique relies on employing the information of a data curve in concert with the information at the design point. Further, the learning capability of ANN technique is integrated to the potential of fuzzy logic. A comparison of the predicted results with experimental data reveals a very good agreement. The proposed technique has not only the capability to model the nonlinear surge line as well as the kink in a classical compressor performance map but also it can be used as an alternative tool to foresee the effect of modification of design variables, as well as to guide the design optimization procedure in a short time frame.
Energy Multiplier
Authors: Vucetic Tomislav
Published: May 2009

What I invented is a method on how to use gravitational and buoyant forces and generate multiple times more energy than energy is spent. In another words, generated energy is greater then spent energy. Even though this is considered as not possible with today’s scientific knowledge, I have experimentally proved it on miniature prototype I’ve made and tested. The measurement on my miniature prototype shows that generated energy is greater than energy we have to spend in order to produce energy. This method may provide as much energy as we want at any point on Planet Earth. There will be no need to burn gas or any other material in order to produce energy, as it is today. All energy needs anywhere in the World will be provided using this method. Today we use gasoline or other material to burn in order to produce energy. Ultimately, using this method to generate energy pollution and other environmental problems will be significantly reduced or even eliminated. The biggest obstacle with this method is to convince other people to believe that my claim is feasible in practice. Even though, I’ve made and tested prototype to prove my claim, still resistance and disbelieve exist. Reason for disbelieve is that my method violates existing First Law of Thermodynamic and therefore is considered as not possible. The method is very simple, but in order to generate significant amount of energy Multiplier Device must be quite a massive. Size of the Device is in direct proportion with energy wanted to generate. For example, Device should be about 30 feet high and 9 feet in diameter in order to produce about 5000 J/sec, which is to have power about 5kWatts. Yes, I’ve made much smaller Device to prove the feasibility of my method, by measurement and calculation. To make Energy Multiplier Device operational without any energy from outside, the size of the Device must be much greater. How the World will benefit from this project? First, this method of energy generation will allow to produce as much energy as we want at any point on Planet Earth, at least theoretically. Amount of energy produced using this method is in direct proportion with the dimensions. If we are able to make Device with unlimited height, the Device will be able to produce unlimited amount of energy. The method produces 100% clean energy, so the benefits will be: – to eliminate burning any material to produce energy; – to eliminate CO2 generation, main reason for climate change (global warming); – to significantly reduce air pollution, if not eliminate; – to eliminate environmental problems; – To provide enough energy for unlimited use; – to provide energy independence for any entity, Country, State, Household, etc; – other benefits are up to your imaginations. By the way, this project has been selected for oral presentation at World Renewable Energy Congress, Florence, Italy, 19–25 August 2006.
Comprehensive Piping Vibration Monitoring Programs
Authors: Szasz Gyorgy , Fujikawa Karen K.
Published: May 2009

Though piping is one of the largest and most expensive types of components in a plant, piping vibration is seldom monitored in a routine manner. Piping itself rarely fails due to vibration, but the same can not be said for related components such as supports, welds, valves, etc. Typically the only time piping vibration is monitored is if high vibration is perceived by operators or is expected due to plant operational changes such as uprates or major component replacements. The procedure for a comprehensive piping vibration monitoring program is thus not as widely known as that for other components such as rotating machinery. This paper presents the steps involved with monitoring piping vibration, obtaining meaningful data and ways to interpret the data. It could be viewed as a primer to those who have never been involved with vibration testing on piping, or as a guideline and checklist for those who have.
Aerodynamic Analysis Using CFD for Gas Turbine Combustion Chamber
Authors: Rodrigues Lucilene O. , Alencar Harley S. , Nascimento Marco A. R. , Venturini Osvaldo J.
Published: May 2009

In the past few years, with the development of advanced numerical computational codes, numerical simulation became a promising option to developing and improving the technology in different fields. The obtained results by simulations are used to get important information during the design phase or optimization of industrial equipment. Its employment generates reliable results at low cost due to the reduced number of experiments as well as the opportunity to develop new products and perform many simulations before its production. However, the numerical simulation credibility can only be verified when compared to the obtained results by experiments. This work aims to present and evaluate different aerodynamics models applied to combustion chambers using a CFD tool. In addition, aerodynamic analysis is made in a model of combustion chamber, where the flow is simulated with successive refining of the mesh as part of its validation process. For it, it is used a Low Nox Emission Combustion Chamber from Floxcom project as reference to validate turbulence models. Once that it is done, the selected turbulence model with satisfactory precision is used to describe the aerodynamic behavior of an annular combustion chamber from velocity and pressure distribution, which are important parameters to set load losses and recirculation intensity, which can affect the complex phenomenon of combustion.
Gas Turbine and MSW Boiler Hybrid Combined Cycles for High-Efficiency Power Production
Authors: Qiu K. , Hayden A. C. S.
Published: May 2009

The present work investigates gas turbine and municipal solid waste (MSW) incinerator hybrid combined cycles for power production. The aims are to achieve high efficiency for energy recovery from MSW while minimizing environmental impacts. In the combined cycles, the topping cycle consists of a gas turbine, while the bottoming cycle is a steam cycle, utilizing the heat from MSW combustion. Comprehensive simulations were made to analyze the viability of the combined cycles and their thermodynamic advantages over conventional incineration of MSW. The results showed that the hybrid combined cycles could offer dramatically higher efficiency for power production and provide practical solutions to problems typically associated with MSW. The environmental impact has been examined and it is shown that the combined cycles could provide an effective means of reducing greenhouse gas emissions. The capital and operating analyses indicate that the combined cycles for power production and waste handling are economically competitive.
Development of a Computational Model to Evaluate Steam Surface Condenser Tubing Modifications
Authors: Pearce Richard E. , Becker Bryan R.
Published: May 2009

The objective was to provide a useful computational tool for assessing the impact of condenser tube modifications on power plant condenser performance and unit heat rate, which directly affect the operating cost. To achieve this, a methodology was utilized to evaluate the economics of condenser modifications based upon design and economic information. The numerical model of condenser performance was developed using the Heat Exchanger Institute method and the Resistance Summation method. The software calculates results based on both methods but this paper will only discuss the results from the Heat Exchanger Institute method for the case study. Since condenser performance has a direct impact upon fuel costs, heat rate, power production and emissions, this computational model can be used to assess the economic impact of a proposed condenser tubing replacement over a specified service life. A case study will be discussed concerning a condenser tube replacement project that was analyzed to determine the ideal replacement tube material for the relevant parameters associated with this particular unit.
A Novel Online Structure Damage Identification Using Principal Component Analysis (PCA)
Authors: Hong Soonyoung , Shen M.-H. Herman
Published: May 2009

A novel online structure damage identification using Principal Component Analysis (PCA) techniques and the perceptron backpropagation neural network is presented. There are three phases to execute this method. In Phase I, system modal information, frequencies and mode shapes, are calculated. Phase II is for damage location identification; the Residual Force Vectors (RFVs) are computed as input to the first neural network. Then the network was trained to simulate damage location identification. Phase III is the severity identification step. The PCA method is used to modify the input for the second neural network. Then this network identifies the severity. There are three advantages of using the PCA method, First, PCA method characterizes the original modal information precisely. Second, PCA method creates the unique data for different damage cases unlike other modal property based data. Third, the accuracy of the damage identification improves significantly, when compared with previously developed methods. This method can be operated online for the real time structural damage identification.
Designing Boiling Condenser for More Efficiency in Power Plants and Less Environment Defects
Authors: Sharifpur Mohsen
Published: May 2009

One of the most important problems in the power plants is to increase the thermal efficiency of the cycle. Most of the works in this area is focused on regeneration devices, removing the heat losses of components…But usually, about half of the input energy in the thermal cycle wastes in the condensers. In this day and age with greenhouse effect and global warming problem, the less environment defect is also another important subject. In this work, a new condenser is offered that is the same as a core of BWR nuclear reactors, then during the working fluid is condensing in a cycle it is a boiling generator (boiling heat exchange) for another cycle. In this way not only could change some parts of unused energy to work, but also it has more capability with environment. It is possible to design this process several times with different cycles and different working fluids to low heat wastes from condensers. Here, it is offered this idea by using the data of Catalagzi power plant in Turkey. The results confirm that the thermal efficiency increases at least %7.5. It can use this method for most of the power plants or somewhere that needed to remove some heat from a device, same as radiators of the automobiles.
TELEPORTING N ROTATIONS ONTO N REMOTE QUBITS BY AN ENTANGLED QUDIT CHANNEL
Authors: CHEN LIBING , LU HONG , CHEN WEICHENG , JIN RUIBO
Published: May 2009

N rotations can be teleported simultaneously onto a group of remote qubits deterministically or probabilistically with the aid of an entangled qudit pair. We present a scheme for such a kind of remote control of quantum gate. We are mainly focused on the remote rotation around a fixed axis. We first present an explicit scheme for deterministically and exactly teleporting the N rotations by using a maximally entangled qudit pair as quantum channel. We also put forward a scheme for probabilistically implementing the N remote rotations with unit fidelity by employing a partially entangled qudit pair as the quantum channel. An analysis of the scheme indicates that use of partially entangled quantum channel for teleporting the N rotations leads to the problem of "the general optimal information extraction".
LOW-FIELD ELECTRON TRANSPORT PROPERTIES IN ZINCBLENDE AND WURTZITE GaN STRUCTURES USING AN ITERATION MODEL FOR SOLVING BOLTZMANN EQUATION
Authors: ARABSHAHI H. , MOWLAVI A. A.
Published: May 2009

An iteration calculation has been carried out to study electron transport properties in zincblende and wurtzite GaN materials. The two-mode nature of the polar optic phonons is considered jointly with deformation potential acoustic, piezoelectric, ionized impurity scattering. Band non-parabolicity, admixture of p functions, arbitrary degeneracy of the electron distribution, and the screening effects of free carriers on the scattering probabilities are incorporated. Electron drift mobility in both zincblende and wurtzite GaN crystal structures are calculated for different temperature and doping dependencies. It is found that the electron mobility decreases monotonically as the temperature increases from 100 K to 600 K. The low temperature value of electron mobilty increases significantly with increasing doping concentration. The agreement of iterative results with the available experimental data is found to be satisfactory.
THEORETICAL STUDY OF OH-INITIATED ATMOSPHERIC OXIDATION FOR PROPYL VINYL ETHER
Authors: HE MAOXIA , WANG HUI , SUN XIAOYAN , ZHANG QINGZHU , WANG WENXING
Published: May 2009

This paper reports a theoretical study on the reaction of propyl vinyl ether (PVE, CH3CH2CH2OCH=CH2) with OH radicals in the presence of O 2 and NO x. The reaction pathway has been studied with the density functional theory (DFT/B3LYP) at the 6-31G* level. The total energies of all geometries are corrected at the MP2/6-311+G** level. The profile of the potential energy surface was constructed. The possible channels involved in the reaction were discussed. The results show that six product pathways are energetically feasible for the degradation of PVE initiated by OH radicals in the atmosphere. The main products for this degradation reaction are propyl formate, formaldehyde, and glycolic acid propyl ester in which propyl formate and formaldehyde are mainly from the OH addition to C5 atom.
INTERACTIONS BETWEEN HUMAN SLINGSHOT PHOSPHATASE 2 AND PHOSPHO-COFILIN: A MOLECULAR DYNAMICS STUDY
Authors: ZHAN JIN-HUI , ZHAO XI , HUANG XU-RI , SUN CHIA-CHUNG
Published: May 2009

Human slingshot phosphatase 2 (SSH2) is one of the dual specificity protein tyrosine phosphatases, which can activate cofilin substrate by binding its phosphorylation state. Because the interaction model of SSH2 and phospho-cofilin (P-cofilin) was unknown, we obtained the complex through macromolecular docking method. The molecular dynamics studies were used to investigate the complex dynamics in an aqueous solution. To understand the binding specificity, the free energy was calculated with the molecular mechanics Poisson–Boltzmann surface area (MM/PBSA) approach and the interaction mode in active site was analyzed. The results indicated that the interaction of the P-loop of SSH2 with phosphoserine of human P-cofilin was stabilized by molecular mechanics energy and nonpolar solvation energy components, while polar solvation energy and the entropic contributions were unfavorable for the combination of the two proteins. In addition, the electrostatic contributions were negative for the formation of the complex on the whole, but seen from the active local, the Coulomb interaction between the phosphoserine and the P-loop residues could play an important role in determining substrate specificity.
USE OF BINOMIAL COEFFICIENTS IN FAST AND ACCURATE CALCULATION OF CLEBSCH–GORDAN AND GAUNT COEFFICIENTS, AND WIGNER n - j SYMBOLS
Authors: GUSEINOV I. I. , MAMEDOV B. A. , ÇOPUROĞLU E.
Published: May 2009

Using binomial coefficients, the new simple and efficient algorithms for the accurate and fast calculation of the Clebsch–Gordan and Gaunt coefficients, and Wigner n - j symbols for n = 3, 6, 9 are presented. For quick calculations, the binomial coefficients are stored in the memory of the computer. It is demonstrated that the use of binomial coefficients greatly reduces the CPU time. The numerical results presented are in complete agreement with those obtained in the alternative evaluation procedure. The method suggested is completely general and free of any restrictions.
Trends Shaping Public Sector Transformation: Knowledge Management, E-Government and Enterprise Architecture
Authors: McNabb David E. , Barnowe J. Thad
Published: May 2009

This paper examines three converging trends in the public sector in the early years of the 21st century: the loss of critical knowledge due to large numbers of retiring government workers, the increasing demand for information and communications technology needed to maintain growth in the scale and scope of e-government, and the requirement to parlay investments in enterprise architecture into effective knowledge management and service delivery efficiency. It includes brief historical reviews of each of these trends, their implementation, and how they are being integrated into initiatives for transforming governments from reactive, bureaucratic systems to visionary, proactive, market-oriented learning organisations. The paper concludes with a discussion of the role played by changes in public sector organisational cultures in successfully addressing these three trends and achieving goals of transformation.
Identifying Conditions to Implement Strategic Knowledge Management in Brazilian Corporations — SKM Math Model Application
Authors: Miranda R. C. R.
Published: May 2009

This is a step forward in researching about Strategic Knowledge Management — SKM. Firstly, an overview of SKM is presented and indicating the three integrative models: conceptual model, mathematical model and systemic model. After that, the SKM math model is deeply described in order to establish a framework to the study. The research objective was to evaluate conditions to implement SKM in Brazilian corporations. Thus, a methodology of four steps was applied: formulating a questionnaire, considering variables related to systemic factors — cognition, technology, organisational culture, managerial style and context — developing a Math Model Software, that was used to collect data and consolidating results by using a MS Excel; preparing a team of researches that comprised 29 students of the Intelligence Competitive MBA in the Universidade de Brasília. The research considered 15 companies in Brazil, mostly public ones, and 56 strategists and decision makers were heard. Results revealed that the conditions are unfavorable to implement SKM model and improvement actions on systemic factors are considerably required.
Multidimensional Models of Information Need
Authors: Xu Yun-jie (Calvin) , Tan Kai Huang (Joseph)
Published: May 2009

User studies in information science have recognised relevance as a multidimensional construct. An implication of multidimensional relevance is that a user's information need should be modeled by multiple data structures to represent different relevance dimensions. While the extant literature has attempted to model multiple dimensions of a user's information need, the fundamental assumption that a multidimensional model is better than a uni-dimensional model has not been addressed. This study seeks to test this assumption. Our results indicate that a retrieval system that models both topicality and the novelty dimension of a users' information need outperforms a system with a uni-dimensional model.
Bioengineering Challenges for Heart Valve Tissue Engineering
Authors: Sacks Michael S. , Schoen Frederick J. , Mayer John E.
Published: May 2009

Surgical replacement of diseased heart valves by mechanical and tissue valve substitutes is now commonplace and enhances survival and quality of life for many patients. However, repairs of congenital deformities require very small valve sizes not commercially available. Further, a fundamental problem inherent to the use of existing mechanical and biological prostheses in the pediatric population is their failure to grow, repair, and remodel. It is believed that a tissue engineered heart valve can accommodate many of these requirements, especially those pertaining to somatic growth. This review provides an overview of the field of heart valve tissue engineering, including recent trends, with a focus on the bioengineering challenges unique to heart valves. We believe that, currently, the key bioengineering challenge is to determine how biological, structural, and mechanical factors affect extracellular matrix (ECM) formation and in vivo functionality. These factors are fundamental to any approach toward developing a clinically viable tissue engineered heart valve (TEHV), regardless of the particular approach. Critical to the current approaches to TEHVs is scaffold design, which must simultaneously provide function (valves must function from the time of implant) as well as stress transfer to the new ECM. From a bioengineering point of view, a hierarchy of approaches will be necessary to connect the organ-tissue relationships with underpinning cell and sub-cellular events. Overall, such approaches need to be structured to address these fundamental issues to lay the basis for TEHVs that can be developed and designed according to truly sound scientific and engineering principles.
Cancer Cells in Transit: The Vascular Interactions of Tumor Cells
Authors: Konstantopoulos Konstantinos , Thomas Susan N.
Published: May 2009

Metastasis is a highly regulated, multistep process in which cancerous cells shed from the primary tumor and enter the circulatory system, where they interact extensively with host cells before they lodge and colonize the target organ. The adhesive interactions of circulating tumor cells with platelets, leukocytes, and endothelial cells facilitate their survival and extravasation from the vasculature, thus representing critical kick-off events for the colonization of distant organs. This review presents our current mechanistic knowledge on vascular interactions of tumor cells, and it discusses biochemical and cell and molecular biology techniques used for the identification of novel receptor-ligand pairs mediating these interactions. This review brings together diverse observations about the contributions of key molecular constituents, including selectins, fibrin(ogen), and CD44, in one mechanistic interpretation. Understanding the molecular underpinnings of adhesive interactions between tumor cells and host cells may provide guidelines for developing promising antimetastatic therapies when initiated early in the course of disease progression.
Durability of Resistance in Tomato and Pepper to Xanthomonads Causing Bacterial Spot
Authors: Stall Robert E. , Jones Jeffrey B. , Minsavage Gerald V.
Published: May 2009

Both hypersensitive and quantitative forms of resistance to the bacterial spot pathogens (Xanthomonas spp.) occur in pepper and tomato. Five resistance genes involved in hypersensitivity in pepper and four in tomato have been identified so far. The corresponding pathogen avirulence genes have been cloned and characterized, and features, including a propensity for accumulating mutations and at times, loss of plasmid-borne avirulence genes, are known to occur. The frequency of these changes affects race composition among pathogen populations and determines the durability of the corresponding plant resistance. At least four different species of Xanthomonas are known to cause bacterial spot, and these can differ in specific avirulence gene content. Quantitative or multigenic resistance has also more recently been researched and appears to be more durable than the hypersensitive resistance. Two recessive genes have been identified that yield a nonhypersensitive form of resistance in pepper and together can provide strong resistance. More emphasis is being given to transfer of quantitative trait resistance to commercial cultivars of both tomato and pepper.
Recent Evolution of Bacterial Pathogens: The Gall-Forming Pantoea agglomerans Case
Authors: Barash Isaac , Manulis-Sasson Shulamit
Published: May 2009

Pantoea agglomerans, a widespread epiphyte and commensal bacterium, has evolved into an Hrp-dependent and host-specific tumorigenic pathogen by acquiring a plasmid containing a pathogenicity island (PAI). The PAI was evolved on an iteron plasmid of the IncN family, which is distributed among genetically diverse populations of P. agglomerans. The structure of the PAI supports the premise of a recently evolved pathogen. This review offers insight into a unique model for emergence of new bacterial pathogens. It illustrates how horizontal gene transfer was the major driving force in the creation of the PAI, although a pathoadaptive mechanism might also be involved. It describes the crucial function of plant-produced indole-3-acetic acid (IAA) and cytokinines (CK) in gall initiation as opposed to the significant but secondary role of pathogen-secreted phytohormones. It also unveils the role of type III effectors in determination of host specificity and evolution of the pathogen into pathovars. Finally, it describes how interactions between the quorum sensing system, hrp regulatory genes, and bacterially secreted IAA or CKs affect gall formation and epiphytic fitness.
Migratory Plant Endoparasitic Nematodes: A Group Rich in Contrasts and Divergence
Authors: Moens Maurice , Perry Roland N.
Published: May 2009

Species of migratory plant endoparasitic nematodes of three nematode families, Pratylenchidae, Anguinidae, and Aphelenchoididae, show marked variation in life cycles and fascinating contrasts in host-parasite interactions. The necessity for survival for periods in the absence of a host has resulted in some remarkable behavioral and physiological adaptations, especially in relation to anhydrobiotic survival. Many species are of major economic importance, and interactions with other pathogens enhance crop damage and yield loss. No single management strategy for endoparasitic nematodes is possible because control options have to be tailored to the nematode species, crop type, location, and economic returns. In this review, we focus on the contrast in life cycles and the wide spectrum of adaptations to obligate parasitism of most species of plant endoparasitic nematodes and examine how these aspects impinge on management options.
An Optical Approach for the Determination of Droplet Volumes in Nanodispensing
Authors: Thurow Kerstin , Krüger Thomas , Stoll Norbert
Published: May 2009

This paper looks at the use of drop‐on‐demand technology in automated life science laboratories. One significant feature of the droplets generated is the enormously high uniformity under constant conditions. However, there is also a relatively strong dependency on environmental conditions. Many different kinds of liquids are used in laboratory applications, some with unknown properties in advance. In light of this and the special way in which the droplets are created, there is one major question which needs answering in relation to the use of this technology in the area of laboratory automation: What is the volume of the drops generated? This paper will present a solution which can be applied in practice. Besides the technical implementation demonstrated, further alternatives will also be presented. Ultimately, dosing systems with greater autonomy should result from the optimizations demonstrated in this paper.
Delivering Diagnostic Quality Video over Mobile Wireless Networks for Telemedicine
Authors: Rao Sira P. , Jayant Nikil S. , Stachura Max E. , Astapova Elena , Pearson-Shaver Anthony
Published: May 2009

In real-time remote diagnosis of emergency medical events, mobility can be enabled by wireless video communications. However, clinical use of this potential advance will depend on definitive and compelling demonstrations of the reliability of diagnostic quality video. Because the medical domain has its own fidelity criteria, it is important to incorporate diagnostic video quality criteria into any video compression system design. To this end, we used flexible algorithms for region-of-interest (ROI) video compression and obtained feedback from medical experts to develop criteria for diagnostically lossless (DL) quality. The design of the system occurred in three steps-measurement of bit rate at which DL quality is achieved through evaluation of videos by medical experts, incorporation of that information into a flexible video encoder through the notion of encoder states, and an encoder state update option based on a built-in quality criterion. Medical experts then evaluated our system for the diagnostic quality of the video, allowing us to verify that it is possible to realize DL quality in the ROI at practical communication data transfer rates, enabling mobile medical assessment over bit-rate limited wireless channels. This work lays the scientific foundation for additional validation through prototyped technology, field testing, and clinical trials.
Spastic Paraparesis Following Cocaine Inhalation
Authors: Savage Henry Oluwasefunmi , Roesner Malin , Cohen David
Published: May 2009

Cocaine use is reaching epidemic proportions in the UK and the consequences are a number of debilitating effects. Strokes may result from a number of mechanisms related to cocaine use. This report describes a case of cocaine induced stroke in an apparently healthy young man with unusual patterns of radiological findings on his brain MRI.
Some Common Fixed Point Results in Cone Metric Spaces
Authors: Arshad Muhammad , Azam Akbar , Vetro Pasquale
Published: May 2009

We prove a result on points of coincidence and common fixed points for three self-mappings satisfying generalized contractive type conditions in cone metric spaces. We deduce some results on common fixed points for two self-mappings satisfying contractive type conditions in cone metric spaces. These results generalize some well-known recent results.
Ectodermal Dysplasia with Amastia: A Case of One-Step Reconstruction
Authors: Klinger M. , Caviggioli F. , Banzatti B. , Fossati C. , Villani F.
Published: May 2009

Background. Female patients presenting amastia associated with ectodermal dysplasia are not frequently encountered, but they are of great clinical interest and surgically demanding. Traditionally, skin alterations related to Ectodermal Dysplasia have addressed plastic surgeons to perform a two-stage approach in amastia associated with this congenital pathologic condition. This article describes an alternative method for correcting this deformity trough a mammary reconstruction in one surgical stage.Materials and Methods. We report a case of 26-year-old female patient with bilateral amastia associated with ectodermal dysplasia. Amastia in this patient was treated with implantation of subpectoral silicone gel prostheses, without previously breast tissue expansion.Results. At 18 months of follow-up after surgey, there were no complications and excellent cosmetic results were achieved. Patient and surgeon satisfaction was high and the patient underwent a bilateral areola-tattoo.Conclusions. One-stage mammary reconstruction have showed to be a reliable and effective technique also when amastia is associated with Ectodermal Dysplasia, suggesting a still satisfying biomechanical performance of the skin in this pathology.
Accuracy of Computed Tomographic Colonography for the Detection of Polyps and Colorectal Tumors: A Systematic Review and Meta-Analysis
Authors: Chaparro María , Gisbert Javier P. , del Campo Lourdes , Cantero José , Maté José
Published: May 2009

Background: The real accuracy of computed tomographic colonography (CTC) is still unknown. Objective: To perform a meta-analysis of the diagnostic accuracy of CTC for the detection of polyps and colorectal tumors. Methods: Selection of studies:Studiesassessing the accuracy of CTC for the detection of colorectal polyps and tumors were selected. Data synthesis:Meta-analyses combining sensitivities, specificities and likelihood ratios (LRs) for the diagnosis of polyps and colorectal tumors were carried out. Results: Forty-seven studies, providing data of 10,546 patients, were included. Overall per-polyp sensitivity of CTC was 66% (64–68%), for polyps 6–9 mm in size it was 59% (56–61%), and 76% (73–79%) for polyps larger than 9 mm. Overall per-patient sensitivity was 69% (66–72%), for polyps 6–9 mm 60% (56–65%), and 83% (70–85%) for lesions larger than 9 mm. Overall CTC specificity was 83% (81–84%). Positive and negative LRs were 2.9 (1.8–4) and 0.38 (0.27–0.53), respectively; for polyps 6–9 mm in size, they were 3.8 (2.5–5.7) and 0.4 (0.27–0.59), and 12.3 (7.7–19.4) and 0.19 (0.12–0.3) for polyps larger than 9 mm. Conclusion: CTC is highly specific for the detection of colorectal polyps and tumors. Some studies reported high sensitivities, but the results of the studies were highly heterogeneous, while the studied variables explained only part of this discrepancy.