bluuebunny/crossref_metadata_2025 huggingface dataset:
Pd Supported on Ce/Zr Mixed Oxides in the Reduction of NO with Propylene in Oxidizing Conditions
Authors: Gonzalez-Marcos M. P. , Betolaza Ainhoa , Gutiérrez-Ortiz Miguel Angel , González-Velasco Juan Ramon
Published: March 2007

The last generation of catalysts for automotive emissions has substituted the traditional ceria by cerium-zirconium mixed oxides, due to their increased oxygen storage capacity, selectivity to the desired products (mostly N2) and durability; while increasing the proportion of palladium, due to its interesting behavior. Using simplified feed-streams with only three components: propylene, NO and O2, plus the N2 carrier, and with data of integral reactor in the range 200300ºC, we have performed experiments in order to obtain kinetic data with a 0.5 %Pd/Ce0.68Zr0.32O2 catalyst. The results have shown that, in the studied range, inlet reaction rates of reactants consumption and products formation can be explained by a Mars-Van Krevelen mechanism in which O2 and NO oxidize the support, and products formation takes place via reduction of the support by the rest of the reactants. Net formation of NO is observed in the low-temperature range, while the opposite is truth in the high-temperature range. Although this behavior has no effect during normal operating conditions in the automobile, it could during cold start up. Also, it is interesting to note that, at low temperature, a significant amount of NH3 decreasing with temperature and some N2O with a maximum at intermediate temperature (around 275ºC) are formed even though the conditions were highly oxidizing, provided that C3H6 is present. NO, on the other hand, is the precursor for NO2.
Leaching of Metallurgical Solid Wastes to Obtain Iron Salts for the Pharmaceutical Industry
Authors: Fernandez Gustavo , Diaz Zahili , Menéndez Zurima , Pérez Oscar , Zarragoitia Alain , Benitez Malvina , Perdomo Iraelio
Published: March 2007

One of the main uses given to ferrous sulphate in the pharmaceutical industry is that of iron supplement. The objectives of this work were to recycle a Cuban metallurgical solid waste with high iron concentration in its two oxidation forms, as well as the finding of optimal conditions for the leaching reaction of this solid waste with sulfuric acid. These results will allow defining a technology for the synthesis of iron inorganic salt for the pharmaceutical industry. A complete factorial experimental design was made, which included three Independent variables on three different levels (3^3) in order to optimize extraction of iron (II) and iron (III). These variables were: sulfuric acid concentration, reaction temperature and molar relation between sulfuric acid and both iron species. The goal of multiple optimizations was to maximize conversions of both iron species and their concentrations in the final liquor, favouring the first.
An Explicit Method for the Packing Limit Management in Dense Gas-Solid Flow CFD Simulations on Both Structured and Unstructured Grids
Authors: Passalacqua Alberto , Marmo Luca
Published: March 2007

An explicit method for limiting the volume fraction of the dispersed phase in the CFD simulations of dense gas-solid flows is described and validated both on structured and unstructured computational grids. The procedure is based on the excess solids volume correction method proposed by Lettieri et al. (2003), which has been extended in this work to non-uniform grids made of cells having different shape and size. The method has been implemented in OpenFOAM and validated through the simulation of a fluidised bed in which the superficial gas velocity has been reduced to a value close to zero.
Normalization of Dye Bias in Microarray Data Using the Mixture of Splines Model
Authors: Joo Yongsung , Casella George , Booth James , Lee Keunbaik , Enkemann Steven
Published: March 2007

This paper discusses characteristics of dye biases in microarray data that the conventional normalization methods do not handle, and proposes a new normalization method involving a mixture of splines model. We also develop a test for between-group comparisons of each gene that is designed to be used with our proposed method.
Super Learning: An Application to the Prediction of HIV-1 Drug Resistance
Authors: Sinisi Sandra E. , Polley Eric C , Petersen Maya L , Rhee Soo-Yon , van der Laan Mark J.
Published: March 2007

Many alternative data-adaptive algorithms can be used to learn a predictor based on observed data. Examples of such learners include decision trees, neural networks, support vector regression, least angle regression, logic regression, and the Deletion/Substitution/Addition algorithm. The optimal learner for prediction will vary depending on the underlying data-generating distribution. In this article we introduce the "super learner", a prediction algorithm that applies any set of candidate learners and uses cross-validation to select between them. Theory shows that asymptotically the super learner performs essentially as well as or better than any of the candidate learners. In this article we present the theory behind the super learner, and illustrate its performance using simulations. We further apply the super learner to a data example, in which we predict the phenotypic antiretroviral susceptibility of HIV based on viral genotype. Specifically, we apply the super learner to predict susceptibility to a specific protease inhibitor, nelfinavir, using a set of database-derived non-polymorphic treatment-selected mutations.
Using Duplicate Genotyped Data in Genetic Analyses: Testing Association and Estimating Error Rates
Authors: Tintle Nathan L , Gordon Derek , McMahon Francis J , Finch Stephen J
Published: March 2007

Although researchers use duplicate genotyped data to calculate an inconsistency rate, there is no power analysis to assess the value of the duplicate data. In this paper, we present a model in which the genotyping error rate is related to the inconsistency rate. We extend the g genotype by h phenotype chi-squared test to incorporate the duplicate genotyped data. When a subject is inconsistently genotyped (that is, has two observed genotypes), our procedure is to allocate 0.5 units to each of the two genotypes. We specify the multivariate analysis of variance (MANOVA) test comparing these extended counts. We provide freely available software for this test and also for a permutation test used on small samples. A simulation study shows that the asymptotic null distribution of the MANOVA test holds when the total number of subjects, N, is at least 300. We also document with a simulation study that the asymptotic distribution of this test under various alternative hypotheses is a satisfactory approximation to the simulated power. In all cases, the power of the MANOVA test using the duplicate genotyped data is greater than the power of the chi-squared test ignoring the duplicate data. Power increases ranged from 0.776% to 4.652% for 80% powered tests and 0.292% to 2.028% for 95% powered tests. Researchers now can compute the value of the duplicate genotyped data as part of the design of the study.
Likelihood-Based Inference for Multi-Color Optical Mapping
Authors: Tong Liping , Mets Laurens , McPeek Mary Sara
Published: March 2007

Multi-color optical mapping is a new technique being developed to obtain detailed physical maps (indicating relative positions of various recognition sites) of DNA molecules. We consider a study design in which the data consist of noisy observations of multiple copies of a DNA molecule marked with colors at recognition sites. The primary goal is to estimate a physical map. A secondary goal is to estimate error rates associated with the experiment, which are potentially useful for analysis and refinement of the biochemical steps in the mapping procedure. We propose statistical models for various sources of error and use maximum likelihood estimation (MLE) to construct a physical map and estimate error rates. To overcome difficulties arising in the maximization process, a latent-variable Markov chain version of the model is proposed, and the EM algorithm is used for maximization. In addition, a simulated annealing procedure is applied to maximize the profile likelihood over the discrete space of sequences of colors. We apply the methods to simulated data on the bacteriophage lambda genome.
Educational Competencies to Strengthen Tuberculosis Curricula in Undergraduate Nursing Programs
Authors: Fair Betty S. , Esch Trudy J , Simpson Terri , Field Kimberly , Benkert Ramona , Brackley Margaret , Resnick Barbara
Published: March 2007

Worldwide, at least two million people die annually from tuberculosis (TB), with projections of 36 million more global deaths between the years 2003 and 2020. To help nursing faculty strengthen TB curricula and standardize TB content in national and international undergraduate nursing programs, the Nurse Discipline Group of the National Tuberculosis Curriculum Consortium (NTCC) has developed comprehensive TB core competencies and specific student objectives for the classroom setting. These core competencies address the knowledge, ability, and/or skills required for an undergraduate nursing student to provide qualified holistic care for patients, families, and communities impacted by TB. The NTCC is comprised of a team of multidisciplinary health care educators in the United States, with the primary mission to instill knowledge, skills, and appropriate attitudes in the management of active and latent TB among undergraduate health care students.
The Power of Online Role-Play Simulations: Technology in Nursing Education
Authors: Nelson Denise L. , Blenkin Carol
Published: March 2007

The use and evaluation of an innovative Web-based technology and its suitability for promoting realism when interacting in clinical nursing situations are described. Also discussed are the development, implementation and evaluation of online role-play simulation. Student and faculty-centered insights are shared about the simulation and the technology supporting it. This Web-based learning experience validated literature review findings and offered new understanding about extended learning, projected realism, diversity, seriousness, non-verbal prompting, and evaluation. This simulation used the Fablusi platform in which students experienced the outcomes of their decisions and actions. This Web-based technology can be adapted for different student groups to enhance learning.
Comparing Teaching Practices about Humor among Nursing Faculty: An International Collaborative Study
Authors: Adamle Kathleen N , Chiang-Hanisko Lenny , Ludwick Ruth , Zeller Richard A , Brown Robert
Published: March 2007

Humor has been recognized by nurse researchers as a therapeutic intervention known to have positive psychological and physiological outcomes for patients. There is, however, no research that examines how nurses learn about humor. The purpose of this preliminary study was to examine nursing faculty members' teaching practices about humor education in the classroom and in clinical settings. Nursing faculty members from four nursing programs, two in the United States, one in Northern Ireland, and one in Taiwan, were surveyed about the inclusion of humor in the nursing curriculum. Findings revealed that substantially more humor education was included in clinical settings in the USA and Northern Ireland than in the classroom. In Taiwan, however, humor education was included more in the classroom than in clinical settings. Older and more experienced nurses with higher levels of education reported using less humor in teaching practices.
International Dimensions of Higher Education in Nursing in Canada: Tapping the Wisdom of the 20th Century While Embracing Possibilities for the 21st Century
Authors: Ogilvie Linda D , Paul Pauline , Burgess-Pinto Elizabeth
Published: March 2007

New focus on the internationalization of universities occurred in the late 20th century and higher education in nursing has been quick to embrace the opportunities. In this manuscript, writers provide a brief overview of the nursing and more general literature from the late 20th century relating to key dimensions of internationalization, as well as present data from a survey conducted in 1995-96 of the international activities and dimensions at Canadian faculties/schools of nursing. While it is clear that nurses in Canadian universities were engaged in significant international endeavours in the 20th century, the literature and our experience suggest that the extent of such activity has increased substantially in recent years. Discussion centres on examination of how knowledge generated in the 20th century can inform current internationalization initiatives and on identification of key questions that merit consideration as we move forward in the 21st century.
Measuring Clinical Practice Parameters with Human Patient Simulation: A Pilot Study
Authors: Radhakrishnan Kavita , Roche Joan P , Cunningham Helene
Published: March 2007

Human Patient Simulators (HPS), electronically controlled mannequins as patient models, are increasingly being used in nursing education. However, no studies have validated the influence of systematic practice with HPS on clinical performance of nursing students. This pilot study attempted to identify the nursing clinical practice parameters influenced by HPS by evaluating the clinical performance of 12 senior second degree BSN students in five categories: safety, basic assessment skills, prioritization, problem-focused assessment, ensuing interventions, delegation and communication in a complex two-patient, simulated assignment. Students who practiced with the HPS in addition to their usual clinical training had significantly higher scores than the control group (usual clinical training alone) on Patient Identification (a subcategory of the safety category; p = 0.001), and on Assessing Vital Signs (a subcategory of the basic assessment category; p = 0.009). The control and intervention groups' performances were similar in every other category. Replication of this pilot with a larger sample is recommended.
Evaluating Critical Thinking in Clinical Concept Maps: A Pilot Study
Authors: Hicks-Moore Sandee L , Pastirik Pamela J
Published: March 2007

Today, the complexities in the health care system are challenging nurses to be skillful and knowledgeable critical thinkers and decision makers. To adequately prepare future nurses to meet the challenges, nurse educators must nurture and facilitate critical thinking. One strategy believed to promote critical thinking in nursing education is concept maps. The purpose of this pilot study was to determine the level of critical thinking in the clinical concept maps developed by second year baccalaureate nursing students. Students enrolled in a five-week clinical practicum course were asked to submit their final concept map and participate in a focus group. The data for the study included eighteen concept maps, 1 student focus group and 1 instructor focus group. The Holistic Critical Thinking Scoring Rubric (Facione & Facione, 1994) was used to measure levels of critical thinking, and content analysis was used to analyze focus group data. Results from this study indicated that developing concept maps in the clinical setting fostered critical thinking and improved clinical preparedness.
Exploring the Use of Clinical Laboratories in Undergraduate Nursing Programs in Regional Australia
Authors: Wellard Sally J , Woolf Rhonda , Gleeson Lynne
Published: March 2007

Preparation for clinical practice is arguably a vital component of undergraduate nursing education with clinical laboratories widely adopted as a strategy to support student development of clinical skills. However, there is little empirical evidence about the role laboratories play in students' learning or how they assist in linking theory to practice. This study aimed to explore the current clinical laboratory practices in Schools of Nursing in regional Victoria, Australia through site visits, interviews and review of curricula. Findings revealed that approaches to laboratory learning are based on traditions rather than evidence, and have evolved in response to fiscal and environmental challenges. The predominance of teacher talk in the laboratory, has lead to acute care over other areas of practice. This study indicates a need for rigorous investigation of pedagogies that can support nursing students in preparation for clinical practice. It remains unclear if laboratory learning experiences assist students in the translation of theoretical knowledge to practice.
Why We Can Do Better than New Source Review
Authors: Hsu Shi-Ling
Published: March 2007

The Clean Air Act requires "New Source Review" -- the installation of specific state-of-the-art pollution control equipment when and only when a new polluting plant is constructed, or a "modification" is undertaken on an existing plant. Shi-Ling Hsu argues that this "grandfathering" policy slows the replacement of old plants with new, more efficient, and less polluting ones.
Advance Disclosure of Managers' Stock Trades: A Proposal to Improve Executive Compensation
Authors: Fried Jesse
Published: March 2007

Despite the insider trading laws and Sarbanes-Oxley, Jesse Fried argues that executives still make billions of dollars of insider trading profits each year by timing their stock sales: requiring advance disclosure of such trades would go far to address this problem.
Letter: On Valuing Ecosystem Services
Authors: Wills-Johnson Nick
Published: March 2007

Nick Wills-Johnson wonders whether social network and graph theory could help in valuing ecosystem services.
Letter: Comment on the Economics of Network Neutrality
Authors: Ralph Eric Kodjo
Published: March 2007

Robert Hahn and Scott Wallsten in "The Economics of Net Neutrality" overlook the two-sided nature of the broadband market. This has important implications for market power and their proposed remedies.
Letter: Informed Investors Have Limited Ability to Push Prices to Efficiency
Authors: Serlin Richard H.
Published: March 2007

J. Bradford DeLong and Konstantin Magin's July, 2006 article gave several good reasons why "informed and aggressive" investors will not necessarily push prices all of the way to their fundamental levels, but missing was the fact that there may not be enough such investors given that none will rationally choose to be too aggressive and have too undiversified a portfolio, according to Richard Serlin.
What To Do about Fannie and Freddie?
Authors: Glaeser Edward L , Jaffee Dwight M
Published: March 2007

Edward Glaeser and Dwight Jaffee argue that Freddie Mac and Fannie Mae are actively pursuing great risk at taxpayer expense and private profit: the cure is a tax on their $1.5 trillion in borrowing that could yield as much as $6 billion a year.
American Inequality: From IT Bust to Big Government Boom
Authors: Galbraith James K. , Hale J. Travis
Published: March 2007

James K. Galbraith and Travis Hale argue that the IT bust and the subsequent fall in the NASDAQ led toward a convergence of income across American counties; yet amidst this movement toward greater equality, several counties have gone from rich to richer mainly due to increased government spending under the Bush administration.
Letter: Pay-As-You-Drive Is More Apt to Reduce Accidents than Global Warming
Authors: Nagelhout Peter R
Published: March 2007

According to Peter Nagelhout, pay-as-you-drive automobile insurance could improve the efficiency of the insurance market and improve public safety. It probably will not reduce pollution or oil consumption.
Is a Recession Ahead? The Models Say Yes, but the Mind Says No
Authors: Leamer Edward E
Published: March 2007

Models based on leading indicators suggest that a recession is almost certainly imminent, but Edward Leamer, a prominent econometrician, distrusts the econometrics and argues that the housing slump will be confined to that sector.
Analysis of Ferroresonance in a Power Transformer with Multiple Nonlinearities
Authors: Kumar Goutham , Rajan Saravanaselvan , Rangarajan Ramanujam
Published: March 2007

This paper investigates the chaotic behavior exhibited by a typical ferroresonant circuit under two-phase open condition. The circuit includes multiple nonlinear elements that accounts for transformer core nonlinearities and arrester. In most of the ferroresonance studies the core loss of the transformer is neglected or modeled as linear resistor [1]. The basic model of the system under investigation and solution of the differential equations describing the model are corroborated against MicroTran [2]. Choice of state variables and formulation of state equations are accomplished through a topological approach [3]. Extensive simulations have been carried out to analyze the sensitivity of the state variables with respect to degree of core saturation, amplitude of the Thevenin voltage source and the presence of arrester. Time response plots, phase plots, Poincaré maps and conventional bifurcation diagrams are used to analyze the chaotic behavior. The results reveal that the nonlinear model of core loss has a significant effect on the onset of chaos. The simultaneous presence of arrester and nonlinear model of core loss effectively eliminates the chaotic region for lower value of transformer saturation exponent.
Phasor Dynamics Influence on Electric Power System Performances
Authors: Griffo Antonio , Lauria Davide
Published: March 2007

Dynamic behaviour analysis of electric power system has always played a vital role in operation and planning of power systems. This analysis relies on computer simulation which are usually based on simplifying assumptions which aim at rendering system modelling more amenable to numerical solution. However, it is well known that uncertainties and unmodelled dynamics could in some cases lead to unexpected results. In the paper a simplified dynamic model of transmission network is employed to evaluate the influence of network transients on dynamic behaviour of power systems. Although simplified, this model can easily capture usually neglected dynamics. Applications of this modelling is proposed with respect to two test systems, highlighting the effects of usually unmodelled dynamics.
Modelling of TCSC Controller for Transient Stability Enhancement
Authors: Patel Ramnarayan , Mahajan Vasundhara , Pant Vinay
Published: March 2007

Power engineers are currently facing challenges to increase the power transfer capabilities of existing transmission system. Flexible AC Transmission system (FACTS) controllers can balance the power flow and thereby use the existing power system network most efficiently. Because of their fast response, FACTS controllers can also improve the stability of an electrical power system by helping critically disturbed generators to give away the excess energy gained through the acceleration during fault. Thyristor controlled series compensator (TCSC) is an important device in FACTS family, and is widely recognized as an effective and economical means to solve the power system stability problem. TCSC is used as series compensator in transmission system. In the present work a TCSC controller is designed and tested over a single machine infinite bus (SMIB) as well as a multi-machine power system. Detailed simulation studies are carried out with MATLAB/SIMULINK environment and the effect of the TCSC parameter variations over the system stability is studied.
Electrostatic and Electrodynamic Field Analyses of 33kV Line Insulators
Authors: Metwally Ibrahim A. , Abdus Salam Md , Al-Maqrashi Ali , Sumry Saif AR , Al-Harthy Saif SH
Published: March 2007

Electrostatic and electrodynamic field analyses of 33kV line insulators were introduced to compare the electric-field and the current density profiles of commonly used line insulators in Oman; namely, silicone rubber (SiR) and porcelain line post insulators, and porcelain cap and pin insulator string. SLIM software package was used for such simulation, which is a fully integrated collection of software modules that provides facilities for the generation and solution of electromagnetic finite element models. The simulation results reveal that for the electrostatic simulation under pollution conditions, SiR and porcelain line-post insulators give maximum values of the electric field of 360kV/m and 1700kV/m, respectively. The latter value exceeds the recommended electric field level of 500kV/m. For the electrodynamic simulation under pollution conditions, the electric field and the current density are much higher for porcelain insulator compared to those of SiR insulator. The simulation of four cap-pin standard insulator string reveals that there is high electric field (1250kV/m) at the cap-insulator gap which can cause high current density for polluted case. Finally, the trend of the simulation results has been verified by experimental tests, which has been conducted on different 33kV line insulators having different designs and materials.
Novel STATCOM Controllers for Voltage Stabilization of Stand Alone Hybrid (Wind/Small Hydro) Schemes
Authors: ElMoursi Mohamed S , Sharaf Adel M
Published: March 2007

This paper presents Three novel error driven dynamic controllers for the Static Synchronous Compensator (STATCOM) Facts device to stabilize both Wind Energy Conversion stand alone systems (SWECS) as well as hybrid scheme of wind plus small hydro with employing self excited induction generator. The unified AC system of standalone wind energy conversion scheme and hybrid wind/small hydro scheme are connected to a hybrid electric load. Three novel error driven dynamic controllers are validated for the STATCOM as a voltage stabilization scheme. Two novel controller are error driven dynamic controllers with auxiliary tracking control loop. The first controller is tri loop dynamic error driven controller using the RMS Load bus voltage, RMS-Load Current and the instantaneous AC load power. The second controller is DC voltage dynamic tracking controller using the dc link capacitor voltage. The third dynamic controller is based on the decoupled (d-q) current control strategy, namely the direct and quadrature current component for the STATCOM current. The dynamic response results demonstrated the effectiveness of the STATCOM-Facts device in stabilizing both AC wind energy system and the hybrid wind/hydro scheme by ensuring effective generator/load bus voltage regulation and dynamic reactive power compensation under load, wind and other prime mover excursions.
Bibliographic Review of FACTS and HVDC Applications in Wind Power Systems
Authors: Varma R. K. , Sidhu Tejbir S.
Published: March 2007

With more emphasis being laid on clean and renewable sources of energy, engineers look for the best possible ways to harness the wind energy to the maximum extent. FACTs controllers that were earlier being used at the transmission level find their use at generation level when it comes to extracting reliable and quality power from Wind Energy Conversion Systems (WECS). This article presents a review of the important modeling techniques employed for developing FACTs controllers and examines the role of HVDC-Light transmission in exploiting the Off-shore wind energy resources.
A Simulation-based Spectral Technique for Power Quality and EMC Design of an Independent Power System
Authors: Belov Vladimir , Shamaev Alexey , Leisner Peter , Johansson Alf , Magnhagen Bengt , Belov Ilja
Published: March 2007

A novel simulation-based spectral technique for power quality and electromagnetic compatibility (EMC) design of an independent electrical power system (EPS) has been proposed. Power filter optimization problem has been formulated to provide full solution of the electric power quality and conducted EMI problems in the EPS. The spectral technique has been implemented within a CAD tool. An example of power quality and EMC design has been provided for an independent EPS where an AC power source generates a power, which is comparable to the consumed power, and an additional power filter is calculated for an electronic product including a switch-mode power supply. Current and voltage spectra calculations have been verified with a block-oriented simulation program Simulink. Numerical experiments revealed a number of important features of the proposed spectral technique.
Sensitivity Based Approach for Transmission Congestion Management Utilizing Bids for Generation Rescheduling and Load Curtailment
Authors: Singh Himanshu Kumar , Srivastava S.C. , Sharma Ashwani Kumar
Published: March 2007

One of the most important tasks of System Operator (SO) is to manage congestion as it threatens system security and may cause rise in electricity price resulting in market inefficiency. In corrective action congestion management schemes, it is crucial for SO to select the most sensitive generators to re-schedule their real and reactive powers and the loads to curtail in extreme congestion management. This paper proposed the selection of most sensitive generators and loads to re-schedule their generation and load curtailment based on the improved line flow sensitivity indices to manage congestion. The impact of slack bus on power flow sensitivity factors has been determined to encourage fair competition in the electricity markets. Effect of bilateral and multilateral transactions, and impact of multi-line congestion on congestion cost has also been studied. The generators reactive power bid has been modeled by a continuous differentiable tangent hyperbolic function. The proposed concept of congestion management has been tested on a practical 75-bus Indian system and IEEE-118-bus test system.
Application of Trajectory Sensitivity for the Evaluation of the Effect of TCSC Placement on Transient Stability
Authors: Chatterjee Dheeman , Ghosh Arindam
Published: March 2007

This paper investigates the use of trajectory sensitivity analysis (TSA) technique for assessing the transient stability of a power system at various operating conditions. The effect of placement of a thyristor controlled series compensator (TCSC) as well as the influence of the change in firing angle is also discussed. The TCSC is modeled by a variable capacitor, the value of which changes with the firing angle. The systems studied are the WSCC 3-machine, 9-bus system and IEEE 16 machine 68 bus system. The results using TSA are validated by PSCAD/EMTDC simulation.
Security Constrained Stochastic Multi-objective Optimal Power Dispatch
Authors: Bath Sarbjeet Kaur , Dhillon Jaspreet Singh , Kothari D P
Published: March 2007

A stochastic multi-objective line security constrained problem is formulated to minimize non-commensurable objectives viz. operating cost, polluting gaseous emission and variance of active power generation and reactive power generation, with explicit recognition of statistical uncertainties in the thermal power generation cost coefficients, gaseous emission coefficients, power demands and hence power generations and bus voltages, which are considered random variables. Specific technique is put forth to convert the stochastic models into their respective deterministic equivalents. Fuzzy set theory has been exploited to evaluate the different objectives that are quantified by defining their membership functions. Security of transmission lines with respect to expected active power flow is considered in the form of fuzzy objective function. The solution set of such formulated problems is non-inferior due to contradictions among the objectives undertaken. The weighting method is used to simulate the trade-off relationship between the conflicting objectives in the non-inferior domain. Generally, the weights are either simulated or searched in the non-inferior domain. In the paper Evolutionary search technique is implemented to search the preferred weightage pattern in the non-inferior domain, which corresponds to the best compromised solution. Among the non-inferior solutions, the system operator selects the preferred optimal operating point that provides maximum satisfaction level of the most under achieved objective in terms of membership function and is termed as fitness function. The validity of the proposed method has been demonstrated on an IEEE system comprising of 11-nodes, 17-lines and 5-generators.
Neuro-Wavelet Approach to Time-Series Signals Prediction: An Example of Electricity Load and Pool-Price Data
Authors: Benaouda Djamel , Murtagh Fionn
Published: March 2007

Accurate electricity load and pool-price forecasting can provide a set of vital predicted information that helps generation, transmission and retailer participating companies to bid strategically into a deregulated electricity market in order to maximize their profits and increase returns to their stakeholders. Although a number of forecasting methods have been proposed to solve the short-term and long-term electricity load forecast, pool-price forecasting is a relatively new research area. In this article, we propose an autoregressive approach, based on a wavelet multiscale decomposition, for the prediction of one-hour ahead load and pool price based respectively on historical electricity load, and pool-price data. This approach is based on a multiple resolution decomposition of the signal using the redundant Haar à trous wavelet transform whose advantage is taking into account the asymmetric nature of the time-varying data. There is an additional computational advantage in that there is no need to re-compute the wavelet transform (wavelet coefficients) of the full signal if the electricity and pool price data (time series) is regularly updated. We assess results produced by this multiscale autoregressive method, in both linear and nonlinear variants, with single resolution autoregressive, multilayer perceptron, Elman recurrent neural network and the general regression neural network models. The input data consists of historical load and pool price data, which is collected over a period of 3 years (1999-2001), used for training, and 1 year (2002) used for testing. Experimental results are based on the New South Wales (Australia) electricity load and pool price data that is provided by the National Electricity Market Management Company.
A Test on Probabilistic Reliability Evaluation of the Korea Power System
Authors: Tran TrungTinh , Jungji Kwon , Choi Jaeseok , Jeon Donghun , Choo Jinboo , Han Kyoengnam , Billinton Roy
Published: March 2007

The importance and conduct of necessary studies on grid reliability evaluation have become increasingly important in recent years due to the number of blackout events occurring throughout the world. Additionally, quantitative evaluation of transmission system reliability is very important in a competitive electricity environment. The reason is that successful operation of an electric power under a deregulated electricity market depends on transmission system reliability management. This paper suggests that the important input parameters of a probabilistic reliability evaluation tool for the KEPCO-system by sensitivity analysis of high reliability level operation. Simultaneously, it also presents sensitivity analysis probabilistic reliability evaluation of practical KEPCO-system long-term transmission system expansion planning (2006-2010). The tool utilized a Transmission Reliability Evaluation for Large-Scale Systems (TRELSS) which was developed by EPRI and Southern Company Services Inc.
Explaining the Decreased Use of International Courts - The Case of the ICJ
Authors: Satzer Janina
Published: March 2007

The popularity of the International Court of Justice (ICJ) is the subject of much controversy. This paper examines usage of the ICJ by all United Nations (UN) member states as compared with its usage by those states with the top-ten economies of the world. Five hypotheses explaining the decrease in ICJ usage by the top-ten economies are presented as follows: (1) a home-bias of judges, (2) the diversification of international tribunals, (3) changes in the composition of the cases filed, (4) the (re-)allocation of power, and (5) an increased heterogeneity of external institutions among UN member states. We find empirical evidence that an increase in UN membership has led to increased heterogeneity, which in turn has led to a decline in usage of the ICJ by the top-ten economies.
Drying Kinetics of Malaysian Paddy (Group D Particles) in Spouted Bed Dryer
Authors: Ng Pin Pin , Law Chung Lim , Tasirin Siti Masrinda
Published: March 2007

Spouted bed is suitable for drying of coarse particles which are Group D of Geldarts particle classification. Malaysian grown paddy was used as a Group D sample in a lab-scale spouted bed dryer. Drying was carried out in two different internal structures of the dryer, namely with or without the installation of a draft tube, and at several drying temperatures, air flow rates as well as bed heights. Spouted bed drying kinetics of paddy presented in drying curves showed only induction and falling rate periods, without constant drying rate period. The highest drying rate was achieved when paddy was dried without draft tube at low bed height, high drying temperature and air flow rate.
Shelf Life and Stability Study of Frozen Dough Bread by the Use of Different Hydrophillic Gums
Authors: Asghar Ali , Anjum Faqir Muhammad , Butt Masood Sadiq , Hussain Shahzad
Published: March 2007

The main objective of this work was to determine the influence of different hydrophilic gums on the stability and shelf life of bread dough during frozen storage. Bread dough containing different level of hydrophilic guns were submitted to mechanical freezing at -18° C and stored frozen for up to 60 days. Two types of hydrophilic gums in different combination were tested: for specific loaf volume of breads made from frozen dough and for its shelf life study by measuring its moisture level at 3, 24, 48, 72 and 96 hrs after baking of frozen dough bread. Specific loaf volume was significantly affected by the hydrophilic gums, Arabic gums showed better effect than CMC. Frozen storage of the dough negatively affected the specific loaf volume of the bread. The addition of 3% Arabic Gum had a beneficial effect on the specific loaf volume and moisture contents of the frozen dough bread.
Possibilities of Calcium Fortification of Spreadable Fat
Authors: Kolanowski Wojciech , Jaworska Danuta , Laufenberg Gunther
Published: March 2007

The aim of the study was to evaluate selected quality attributes of low-fat spread fortified with calcium complex isolated form cow milk. Calcium preparations added into foods may influence texture properties of product. In the study texture parameters of milk derived calcium complex enriched spreadable fat were measured using instrumental and sensory methods. Additionally overall sensory quality and chemical indicators i.e. peroxide value and acid value were estimated. All measurements were carried out during 3 months of storage. There was not significant influence of fortification on samples quality. Results of peroxide value measurements may suggest protective influence of added milk calcium complex against oxidation. The average daily portion of enriched spread (30 g) might provide at least 160 mg of best available calcium of milk origin, i.e. 15% of its recommended daily intake, which can significantly improve dietary calcium level.
Application of Response Surface Methodology for Optimizing the Pre-processing Conditions of Bambara Groundnut (Voandzei Subterranea) during Canning
Authors: Afoakwa Emmanuel Ohene , Budu Agnes Simpson , Merson Alan Bullock
Published: March 2007

Bambara groundnut (Voandzei subterranea) seeds were canned with the objective of investigating the optimal pre-processing conditions that would yield the best quality canned product from it. Pre-canning procedures such as blanching time, soaking time and sodium hexametaphosphate [(NaPO3)6] salt concentration were used as the independent variables for a Central Composite Rotatable Design (CCRD). The pre-processing parameters obtained from the CCRD for k = 3 were used for the canning of the bambara groundnuts and the quality characteristics (moisture content, pH of the drained liquid, drained weight, splitting of the seeds, leached solids and seed hardness) of the canned products were studied using response surface methodology. Regression models were generated using regression analysis and used for the plotting of response surface curves. Adequacy of the model equation for predicting the optimum responses were tested in the experiment using the blanching time of 2-12 minutes, soaking time of 0-24 hours and salt concentration [(NaPO3)6] of 0-1%. Three optimal processing conditions of the canning procedures of the bambara groundnuts were determined from the mathematical models. The results revealed that the soaking time, blanching time and salt concentration all significantly (p<0.05) influenced most of the quality indices of the canned bambara groundnuts. The optimal conditions required to achieve the optimum moisture content, pH level and other quality indices studied on the canned bambara groundnuts were blanching time of 5 min, soaking time of 12 h and [(NaPO3)6] salt concentration of 0.5 %. These conditions would give the best quality canned product from bambara groundnut with acceptable quality characteristics.
Mass Transfer Characteristics of Chicken Nuggets
Authors: Ngadi Michael , Dirani Khaldoun , Oluka Sylvester
Published: March 2007

Chicken nuggets were either deep fat fried at three temperatures (150, 170 and 190oC) for 1 to 4 min or oven baked at three temperature levels (200, 220 and 240oC) for 5 to 25 min. The effects of these cooking methods on mass transfer characteristics of chicken nuggets were evaluated. Moisture loss profiles in the breading and core portions of the product were significantly different. There was a rapid moisture loss from the breading portion within the first 2 min of deep fat frying or within the first 15 min of oven baking followed by considerably reduced rates. Moisture loss in the core region changed only slightly in the early stages of frying or oven baking but increased afterwards. Moisture diffusivity in the breading region was evaluated using analytical solution of Ficks second law diffusion equation. Values of moisture diffusivity were from 20.93x10-10 to 29.32x10-10 m2/s for deep fat frying and from 1.90x10-10 to 3.16x10-10 m2/s for oven baking. The activation energies were 8.04 and 25.7 kJ/mol for deep fat frying and oven baking, respectively.
Macromolecular Interactions During Gelatinisation and Retrogradation in Starch-Whey Systems as Studied by Rapid Visco-Analyser
Authors: Sopade Peter A , Hardin Matt , Fitzpatrick Paul , Desmee Helene , Halley Peter
Published: March 2007

Gelatinisation and retrogradation of starch-whey mixtures were studied in water (pH 7) using the Rapid Visco-Analyser (RVA). The starch:whey ratios ranged from 0:100  100:0. Wheat starch, and whey protein concentrate (about 80% solids basis) and isolate (about 96% solids basis) were used. Mixtures with whey isolates were generally more viscous than those with whey concentrates, and this was attributed to fewer non-protein milk components in the former. Whey protein concentrates and isolates reduced the peak, trough and final viscosities of the mixtures, but the breakdown and setback ratios of the mixtures were increased. The gelatinisation temperature increased with whey substitutions indicating that whey protein delayed starch gelatinisation. The temperature of fastest viscosity development decreased as the amount of whey was increased. Whey protein isolate generally exercised a lesser effect than the concentrate. At between 40 - 50% whey substitutions, the dominant phase changed from starch to protein irrespective of the source of the whey protein. An additive law poorly defined selected RVA parameters. Both macromolecules interacted to define the viscosity of the mixture, and an exponential model predicted the viscosity better than the additive law. The results obtained in this study are discussed to assist the understanding of extrusion processing of starch-whey systems as models for whey-fortified snack and ready-to-eat foods.
Friction Factor Prediction for Newtonian and Non-Newtonian Fluids in Pipe Flows Using Neural Networks
Authors: Mittal Gauri S. , Zhang Jixian
Published: March 2007

The friction factors (f) for Newtonian, power law, Bingham plastic and Herschel-Bulkely fluids were predicted after developing and training four neural networks (NN). Three and four layer NN and Wardnet slab were used for f predictions. When average velocity (u), pipe diameter (D), fluid density and fluid viscosity were used for predicting f values for Newtonian fluids, average absolute error was only 0.00004 with standard deviation of 0.00050 and correlation coefficient (r) of 0.9981. When using flow behaviour index (n),u, D, density and consistency coefficient (k) as inputs of an NN for power law fluids, the average absolute error of predicting f was 0.0116 with r of 0.9998. For prediction of f using yield stress, u, D, density and plastic viscosity as inputs to an NN for Bingham plastic fluids, the average absolute error was 0.0044 with r of 0.9961. The average absolute error was 0.0169 with r of 0.9996 for the prediction of f taking n, yield stress, u, D, density and k as inputs to an NN for Herschel-Bulkely fluids. Inputs except n and density and output were transformed on a logarithmic base to 10 scale. Prediction using log f or extension of f limit reduced prediction errors.
Applications of Several Hybrid Drying Methods for a Bioproduct: Effects on Drying Kinetics and Product Colour
Authors: Chua Kian Jon
Published: March 2007

In response to growing expectations for more effective drying of bioproducts with improved quality, this paper presents recent experimental results obtained from employing several hybrid drying techniques. The hybrid drying methods could be classified into thermal and non-thermal processes. The thermal processes included combined convective/infrared and convective-microwave drying while non-thermal process refers to dehydration under conditions of successive pressure drops incorporating an adsorption bed. Potato samples were taken to be the model bioproduct. A comparison of the drying kinetics with product colour degradation showed convective-microwave drying to be an effective method in shortening the drying time to achieve the desired moisture content whilst maintaining acceptable product quality. Bioproduct dehydration in a non-thermal cyclic pressure drop adsorption system resulted in substantial minimisation of the product colour change but at the expense of a longer drying time.
Cassava Mash Dewatering Parameters
Authors: Kolawole Oladele Peter , Agbetoye Leo A.S. , Ogunlowo A. S.
Published: March 2007

A study was conducted to evaluate the parameters affecting the dewatering of cassava mash during processing. First, studies on the pressure distribution within the mash during the dewatering were carried out. Experimental equipment consisting of tyre tube filled with water, a copper tube, and a pressure gauge was designed and fabricated to measure pressure used in expressing the juice contained in the grated cassava mash. It also included a cylindrical dewatering tank made of galvanized steel plate and a sack which was used as control. The tank had 7mm holes drilled at the base to allow the flow of juice. The volume of juice was measured using a measuring cylinder and the stopwatch measured the time. IITA TMS 4(2) 1425 variety of cassava at three levels of maturity age of 9, 12 and 15 months was utilized in the study. The dewatering pressure is from hydraulic jack used to press the grated mash. The dewatering parameters investigated were pressure drop, face area of the filter medium and mash resistance. The results showed that mash resistance varied with the age of the cassava with the highest value of 54,000,000,000 m/kg recorded. Medium Resistance also varied with the age, 33,000,000,000/m was the highest value recorded for 15 months old sample. 0.00371m3 volume of filtrate was obtained from the 12 months old sample with 0.0945 kg mash cake deposit on the filtering medium as the highest deposit. The Kozemy constant value for TMS 4(2) 1425 variety of cassava was found to be 11400000 and Porosity 0.0181, the result presents the distribution and values of identified parameters numerically for equipment designers use.