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Analysis Results (analysis + result)
Selected AbstractsNumerical simulation of rotating bending process for U-tubes in heat exchangersFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 10 2009H.-S. KIM ABSTRACT Heat exchangers comprise thousands of tubes having U-shaped portions. Rotating bending method has been widely utilized to make U-bends. Although this method shows an excellent performance, cracks have been frequently detected in the U-bends due to residual stresses induced by bending. In this paper, the bending process is simulated based on elastic,plastic finite element analyses in order to investigate the magnitude and distribution of the residual stresses including the effects of operating pressure. Analyses results show that the residual stress increases as the radius of U-bend decreases and that operating pressure has a detrimental effect in terms of stress corrosion cracking at the intrados of U-bend. It is thought that these results can be utilized for the estimations of fracture mechanics parameters such as limit load, stress intensity factor and J-integral, prevention of the cracking, and establishment of the optimum inspection strategy for the heat exchanger tubes. [source] EXPRESSION OF A BEE-VENOM PHOSPHOLIPASE A2 FROM APIS CERANA CERANA IN ESCHERICHIA COLIINSECT SCIENCE, Issue 1 2004Li-rong Shen Abstract, The venomous phospholipase A2 (AcPLA2) coding reading region of the Chinese honeybee (Apis cerana cerana), which is composed of 405 bp encoding a mature glycosylated peptide with 134 amino residues was transformed into the expression vector pETblue-1. Then the recombinant vector was introduced into Escherichia coli Tuner (DE3) plac I for expression. Analysis result of SDS-PAGE showed that the expression products had a protein band of about 15kD. Detection of western blot using ant-European honeybee (Apis mellifera) phospholipase A2 (AmPLA2) polyclonal serum as the first antibody showed that the expression products appeared a special blot same as the native AmPLA2. The result demonstrated that the AcPLA2 peptide had been expressed in E. coli and the AcPLA2 has the similar antigenicity as the AmPLA2. [source] Large displacement FEM modelling of the cone penetration test (CPT) in normally consolidated sandINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 7 2003Endra Susila Abstract A new finite element model based on a large strain formulation has been developed to study cone penetration in normally consolidated sand. An auto-adaptive remeshing technique was utilized for handling the very large distortion of sand surrounding the cone tip. A frictional contact interface utilizing Mohr,Coulomb's theory was chosen to represent interactions between the surface of the cone and sand. To model the sand behaviour, the non-associated Drucker,Prager constitutive model was selected. ABAQUS, a commercial finite element software package, was used to implement the model. The explicit solution algorithm was chosen due to its effectiveness for complicated contact problems. Analysis results proved that the model successfully captured the cone penetration behavior in sand. In addition, a chart to predict internal friction angles based on cone tip resistance for different vertical effective stresses was provided. This paper also shows a typical distribution of sleeve resistance, tip resistance,penetration relationship, and typical contours of vertical, horizontal, and shear stresses in normally consolidated sand. Finally, a non-uniform resistance was found along the length of the friction sleeve. Copyright © 2003 John Wiley & Sons, Ltd. [source] Seismic performance evaluation of steel arch bridges against major earthquakes.EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 14 2004Part 2: simplified verification procedure Abstract The performance-based philosophy has been accepted as a more reasonable design concept for engineering structures. For this purpose, capacity evaluation and demand prediction procedures for civil engineering structures under earthquake excitations are of great significance. This work presents a displacement-based seismic performance verification procedure including capacity and seismic demand predictions for steel arch bridges and investigates its applicability. Pushover analyses is employed as a basis in this method to investigate the structure's behaviors. A failure criterion for steel members accounting for the effect of local buckling is involved and an equivalent single-degree-of-freedom (ESDOF) system with a simplified bilinear hysteretic model formulated using pushover analyses results is introduced to estimate the displacement capacity and maximum demand of steel arch bridges under major earthquakes. To check the accuracy of the proposed method, seismic capacities and demands from multi-degree-of-freedom (MDOF) time-history analyses with Level-II design earthquake record inputs modeling major earthquakes are used as benchmarks for comparison. By a case study, it is clarified that the proposed prediction procedure can give accurate estimations of displacement capacities and demands of the steel arch bridge in the transverse direction, while insufficient for the longitudinal direction, which confirms the conclusion drawn in other structure types about the applicability of pushover analyses. Copyright © 2004 John Wiley & Sons, Ltd. [source] Identification of Acipenseriformes species in tradeJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2008A. Ludwig Summary Sturgeons and paddlefishes (Acipenseridae) are highly endangered freshwater fishes. Their eggs (sold as caviar) are one of the most valuable wildlife products in international trade. Concerns of overharvesting and the conservation status of many of the 27 extant species of Acipenseriformes led to all species being included on the CITES Appendices in 1998. Since then international trade in all products and parts from sturgeon and paddlefish has been regulated. However, despite the controls on trade, unsustainable harvesting continues to threaten many populations. Illegal fishing and trade continues to be a threat to the management of these fish. To enforce the regulation of legal trade and prevention of illegal trade, the development of a uniform identification system for parts and derivates of Acipenseriformes has been identified as an urgent requirement. Ideally this system should be suitable for (i) identification at the species-level of caviar and other products from Acipenseriformes; (ii) population identification; (iii) source identification (wild vs aquaculture); and (iv) determining the age of caviar because strict timeframes govern its international trade. This paper reviews the techniques currently available and their potential to be used in an identification system for Acipenseriformes species and their products in trade. A review of all available identification techniques has shown that there is not a single method that can meet all requirements (see i,iv), and it does not appear to be feasible to develop such a method in the near future therefore the most appropriate methods need to be developed for each. Considering the advantages and disadvantages of all techniques reviewed in this document, the following conclusions can be drawn: (i) for the identification of species, approaches are recommended that target mitochondrial cytochrome b sequences (RFLP, nested PCR or direct sequencing). However, they show limitations for the detection of hybrids (although natural hybrids are rare, the number of artificially produced hybrids in aquaculture is increasing) and for the differentiation of the following closely related species complexes: Acipenser gueldenstaedti,Acipenser baerii,Acipenser persicus,Acipenser naccarii; Acipenser medirostris,Acipenser mikadoi; and Scaphirhynchus albus,Scaphirhynchus plathorhynchus,Scaphirhynchus suttkusi; (ii) the identification of different populations of the same species is currently not feasible because genetic data are incomplete for most populations, and stocking and release programmes, which have become more and more common, often result in a mixture of phenotypes and genotypes, thereby impeding the creation and application of such a population identification system; (iii) source identification based on genetic approaches can be excluded at present because there are no genetic differences between wild and hatchery-raised fish. This is the result of the continuing restocking of natural populations with captive fish and vice versa. However, because rearing (i.e. environmental) conditions are different, methods focusing on differences in water quality or food seem to be more appropriate (for example differences in fatty acid composition). So far, very few studies have been conducted and therefore, source identification methods merit further exploration; and (iv) the age of a product in trade cannot be detected by DNA-based methods and protein profiling is undoubtedly impractical due to hard-to-perform, labour-and cost-intensive methods, which are highly susceptible to protein degradation. Arising from the limits discussed above, the next steps in the development of a uniform sturgeon identification system are proposed to be the following: (i) designation of qualified reference laboratories at national levels in (re-) exporting and importing countries. These should be approved through a standardized testing procedure, for instance a ring test on blind samples. Registered laboratories should be published and disseminated and their accreditations should be subject to certain guarantees regarding quality, economic independence and scientific rigour. Operational procedures have to be determined and standardized among reference laboratories; (ii) establishment of reference collections that are accessible to the reference laboratories containing DNA analyses results and information on the location and availability of tissue samples. This is highly recommended as an important step towards a population identification system and indispensable for a general species identification system; (iii) creation of a website access to the reference collections containing the reference database information about genetic samples, comparable to NCBI, which provides background data: sample location; population information; citation; available genetic data; location of archival storage; currently treated and distributed caviar and status of analysis. This website should also be a forum for the exchange of knowledge on and experiences with identification systems, species and population status information, relevant scientific research, etc.; and (iv) the outcome of the trade identification tests should be made available to the reference laboratories for future reference. The universal caviar labelling system could incorporate an indication of the verification of the consignment. In view of the lack of knowledge and the great need to develop a uniform identification system for Acipenseriformes with regard to the importance of the international caviar trade, further scientific guidance and appropriate research is strongly recommended. Progress should be assessed and exchanged on a regular basis. [source] Thermal conductivity and mechanical properties of aluminum nitride filled linear low-density polyethylene compositesPOLYMER ENGINEERING & SCIENCE, Issue 5 2009Junwei Gu To acquire polymer composites with high thermal conductivity and mechanical properties, the aluminum nitride (AlN) microparticles modified with titanate coupling reagent of isopropyltrioleictitanate (NDZ-105) were employed to blend linear low-density polyethylene (LLDPE) via powder mixing method. Thermal conductive coefficient of the AlN/LLDPE composites was measured using hot disk thermal analyzer, and the thermal stability characteristics of AlN/LLDPE composites were mainly investigated via thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC). The results indicated that the use of AlN particles modified by NDZ-105 significantly enhanced thermal conductivity and mechanical properties of AlN/LLDPE composites. The thermal conductivity coefficient , was 1.0842 W/mk with 30% volume fraction of AlN, about three times higher than that of native LLDPE. The tensile strength of composites was maximum (17.42 MPa) with 20% mass fraction of AlN. DSC analyses results indicated that AlN had an influence on the melting temperature and the crystallinity of LLDPE. Additionally, TGA analyses showed that the thermal stability of LLDPE was significantly increased with addition of AlN. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source] Improved EEG source analysis using low-resolution conductivity estimation in a four-compartment finite element head modelHUMAN BRAIN MAPPING, Issue 9 2009Seok Lew Abstract Bioelectric source analysis in the human brain from scalp electroencephalography (EEG) signals is sensitive to geometry and conductivity properties of the different head tissues. We propose a low-resolution conductivity estimation (LRCE) method using simulated annealing optimization on high-resolution finite element models that individually optimizes a realistically shaped four-layer volume conductor with regard to the brain and skull compartment conductivities. As input data, the method needs T1- and PD-weighted magnetic resonance images for an improved modeling of the skull and the cerebrospinal fluid compartment and evoked potential data with high signal-to-noise ratio (SNR). Our simulation studies showed that for EEG data with realistic SNR, the LRCE method was able to simultaneously reconstruct both the brain and the skull conductivity together with the underlying dipole source and provided an improved source analysis result. We have also demonstrated the feasibility and applicability of the new method to simultaneously estimate brain and skull conductivity and a somatosensory source from measured tactile somatosensory-evoked potentials of a human subject. Our results show the viability of an approach that computes its own conductivity values and thus reduces the dependence on assigning values from the literature and likely produces a more robust estimate of current sources. Using the LRCE method, the individually optimized four-compartment volume conductor model can, in a second step, be used for the analysis of clinical or cognitive data acquired from the same subject. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [source] Robust exponential stability for discrete-time interval BAM neural networks with delays and Markovian jump parametersINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 9 2010Jiqing Qiu Abstract This paper investigates the problem of global robust exponential stability for discrete-time interval BAM neural networks with mode-dependent time delays and Markovian jump parameters, by utilizing the Lyapunov,Krasovskii functional combined with the linear matrix inequality (LMI) approach. A new Markov process as discrete-time, discrete-state Markov process is considered. An exponential stability performance analysis result is first established for error systems without ignoring any terms in the derivative of Lyapunov functional by considering the relationship between the time-varying delay and its upper bound. The delay factor depends on the mode of operation. Three numerical examples are given to demonstrate the merits of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd. [source] TCDD suppresses insulin-responsive glucose transporter (GLUT-4) gene expression through C/EBP nuclear transcription factors in 3T3-L1 adipocytesJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 2 2006Phillip Chin-Chen Liu Abstract TCDD is known to reduce significantly the level of the functionally active form of glucose transporter type 4 (GLUT4) in vivo in adipose tissue and muscles. To study the mechanistic basis of this phenomenon, we conducted transient transfection and DNA deletion analysis in 3T3-L1 cells using chloramphenicol acetyltransferase (CAT) reporter plasmids containing the GLUT4 promoter joined to the bacterial CAT. It was found that in transfected control samples, CAT activity was significantly higher in cells transfected with p469CAT and p273CAT than those with p78CAT, indicating that the region between ,78 and ,273 contained elements that play major roles in transactivation of this gene. Treatment with TCDD decreased CAT activity with p469CAT and p273CAT, but not with p78CAT, indicating the same region to contain the element(s) affected by TCDD. A gel-shift (EMSA) analysis result indicated that TCDD shows the profound effect only on the nuclear proteins binding to the [32P]-labeled probe containing C/EBP response element equivalent of the ,265 to ,242 stretch of the GLUT4 promoter. The results of supershift analysis showed that TCDD caused a decrease in the tier of C/EBP, and an increase in that of C/EBP, among the proteins bound to this C/EBP response element. We studied the effect of TCDD in cells overexpressing either C/EBP,, C/EBP,, or C/EBP, through transient transfection of p273CAT or p469CAT. The results clearly showed that the effect of TCDD to suppress the CAT activity of p273 or p469 disappeared in those cells overexpressing C/EBP, or C/EBP,. These results implicate the C/EBP proteins to be the main mediator of suppressive action of TCDD on GLUT4 gene expression in 3T3-L1 cells. © 2006 Wiley Periodicals, Inc. J Biochem Mol Toxicol 20:79,87, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20120 [source] Quantitative Structure,Activity Relationship Studies for the Binding Affinities of Imidazobenzodiazepines for the ,6 Benzodiazepine Receptor Isoform Utilizing Optimized Blockwise Variable Combination by Particle Swarm Optimization for Partial Least Squares ModelingMOLECULAR INFORMATICS, Issue 1 2007Leqian Hu Abstract Binding affinities of a series of substituted imidazobenzodiazepines for the ,6 Benzodiazepine Receptor (BzR) isoform are investigated by the Optimized Blockwise Variable Combination (OBVC) by Particle Swarm Optimization (PSO) based on Partial Least Squares (PLS) modeling. The QSAR analysis result showed that MolRef, AlogP, MRCM**-3, Rotatable bonds (Rotlbonds), Hydrogen Bond Acceptors (Hbond acceptor), five Jurs descriptors, two Shadow indices descriptors and principal moment of inertia are the most important descriptors among all the investigated descriptors. One can change the molar refractivity, the polar interactions between molecules, the shape of the molecules, the principal moments of inertia about the principal axes of a molecule, the hydrophobic character of the molecule, the number of Rotlbonds and Hbond acceptors of the compounds to adjust the binding affinities of imidazobenzodiazepine for the ,6 BzR isoform. The Quantitative Structure,Activity Relationship (QSAR) analysis result was also compared with MLR, PLS, and hierarchical PLS algorithms. It has been demonstrated that OBVC by PSO for PLS modeling shows satisfactory performance in the QSAR analysis. [source] Obesity, Smoking, and Frontal Brain DysfunctionTHE AMERICAN JOURNAL ON ADDICTIONS, Issue 5 2010Lance Bauer PhD Obesity, smoking, and conduct problems have all been associated with decrements in brain function. However, their additive and interactive effects have rarely been examined. To address the deficiency, we studied P300a and P300b electroencephalographic potentials in 218 women grouped by the presence versus absence of: (1) a BMI , 30 kg/m2; (2) recent smoking; and (3) , 2 childhood conduct problems. Analyses revealed smaller P300a and P300b amplitudes over the posterior scalp among recent smokers versus nonsmokers. No corresponding group differences were found in P300 latencies or frontal scalp amplitudes. The most interesting analysis result was an interaction between conduct problems and obesity limited to the frontally generated P300a component: its latency was significantly greater in women with both attributes than in those with either or neither attribute. An exploratory ANOVA, substituting the genotype of a GABRA2 SNP for conduct problems, also demonstrated an interaction with obesity affecting P300a latency. It is hypothesized that conduct problems, and a conduct-problem-associated GABRA2 genotype, decrease the age-of-onset and/or increase the lifetime duration of obesity. As a result, they may potentiate the adverse effects of obesity on frontal white matter and thereby increase P300a latency. Smoking may affect brain function by a different mechanism to reduce posterior scalp P300a and P300b amplitudes while preserving frontal scalp P300a latency and amplitude.,(Am J Addict 2010;00:1,10) [source] Three-dimensional behavior of a spherical self-centering precast prestressed pile isolatorEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 5 2009Rosita Jünemann Abstract A 3D analytical formulation of a precast prestressed pile (PPP) seismic isolator with top and bottom spherical rolling kinematic constraints is proposed. The PPP isolator was initially conceived as a low-cost seismic isolation (and foundation) system for housing units of low-income people. Since these structures are usually located at sites with poor soil conditions, the PPP isolator also works as a foundation pile by connecting the superstructure with more competent soil layers. The non-holonomic nature of the rolling constraint is dealt with by a structural formulation. The proposed 3D formulation is validated by numerical results obtained from a previously proposed formulation for the 2D problem, and a contact finite element model in ANSYS (www.ansys.com). Other issues associated with the dynamic response of isolated structures with the PPP are also examined, such as expected response reductions, variation in the axial force of the central prestressed cable, and torsional response amplifications. Finally, guidelines to estimate the actual 3D response using 2D analysis results are investigated. Copyright © 2009 John Wiley & Sons, Ltd. [source] Use of chemometric methodology in optimizing conditions for competitive binding partial filling affinity capillary electrophoresisELECTROPHORESIS, Issue 16 2008Ruth E. Montes Abstract This work expands the knowledge of the use of chemometric response surface methodology (RSM) in optimizing conditions for competitive binding partial filling ACE (PFACE). Specifically, RSM in the form of a Box,Behnken design was implemented in flow-through PFACE (FTPFACE) to effectively predict the significance of injection time, voltage, and neutral ligand (neutral arylsulfonamide) concentration, [Lo], on protein,neutral ligand binding. Statistical analysis results were used to create a model for response surface prediction via contour and surface plots at a given maximum response (,RMTR) to reach a targeted Kb,=,2.50×106,M,1. The adequacy of the model was then validated by experimental runs at the optimal predicted solution (injection time,=,2.3,min, voltage,=,11.6,kV, [Lo],=,1.4,,M). The achieved results greatly extend the usefulness of chemometrics in ACE and provide a valuable statistical tool for the study of other receptor,ligand combinations. [source] Implementation of chemometric methodology in ACE: Predictive investigation of protein,ligand bindingELECTROPHORESIS, Issue 16 2007Grady Hanrahan Abstract An ACE predictive investigation of protein,ligand binding using a highly effective chemometric response surface design technique is presented. Here, Kd was estimated using one noninteracting standard which relates to changes in the electrophoretic mobility of carbonic anhydrase B (CAB, EC 4.2.1.1) on complexation with the ligand 4-carboxybenzenesulfonamide (CBSA) present in the electrophoresis buffer. Experimental factors including injection time, capillary length, and applied voltage were selected and tested at three levels in a Box,Behnken design. Statistical analysis results were used to create a mathematical model for response surface prediction via contour and surface plots at a given target response (Kd,=,1.19×10,6,M). As expected, there were a number of predicted solutions that reached our target response based on the significance of each factor at appropriate levels. The adequacy of the model was validated by experimental runs with the predicted model solution (capillary length,=,47,cm, voltage,=,11,kV, injection time,=,0.01,min) presented in detail as an example. [source] Ability of different restorative materials to prevent in situ secondary caries: analysis by polarized light-microscopy and energy-dispersive X-rayEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2008Thaís Cachuté Paradella Secondary caries is the main cause of direct restoration replacement. The purpose of this study was to analyze enamel adjacent to different restorative materials after in situ cariogenic challenge using polarized-light microscopy (PLM), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDS). Twelve volunteers, with a low level of dental plaque, a low level of mutans streptococci, and normal salivary flow, wore removable palatal acrylic appliances containing enamel specimens restored with Z250 composite, Freedom composite, Fuji IX glass-ionomer cement, or Vitremer resin-modified glass-ionomer for 14 days. Volunteers dripped one drop of 20% sucrose solution (n = 10) or distilled water (control group) onto each specimen 8 times per day. Specimens were removed from the appliances and submitted to PLM for examination of the lesion area (in mm2), followed by dehydration, gold-sputtering, and submission to SEM and EDS. The calcium (Ca) and phosphorus (P) contents were evaluated in weight per cent (%wt). Differences were found between Z250 and Vitremer, and between Z250 and FujiIX, when analyzed using PLM. Energy-dispersive X-ray analysis results showed differences between the studied materials regarding Ca %wt. In conclusion, enamel adjacent to glass-ionomer cement presented a higher Ca %wt, but this material did not completely prevent enamel secondary caries under in situ cariogenic challenge. [source] Factors Influencing Midlife and Older Adults' Attendance in Family Life Education Programs,FAMILY RELATIONS, Issue 3 2005Sharon M. Ballard Abstract: This study explored the likelihood of midlife and older adults attending a family life education program by assessing learner characteristics and deterrents to and motivators of attendance. Data were collected through a survey mailed to a stratified sample of adults aged 50 and over. Discriminant analysis results based on survey responses from 264 participants suggest that younger individuals with strong religious beliefs, low personal and programmatic deterrents, and high levels of motivation were most likely to indicate future program attendance. Implications for family life education are discussed. [source] Meshless approach to shape optimization of linear thermoelastic solidsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 4 2002Florin Bobaru Abstract This paper presents a formulation for shape optimization in thermoelasticity using a meshless method, namely the element-free Galerkin method. Two examples are treated in detail and comparisons with previously published finite element analysis results demonstrate the excellent opportunities the EFG offers for solving these types of problems. Smoother stresses, no remeshing, and better accuracy than finite element solutions, permit answers to shape optimization problems in thermoelasticity that are practically unattainable with the classical FEM without remeshing. For the thermal fin example, the EFG finds finger shapes that are missed by the FEM analysis, and the objective value is greatly improved compared to the FEM solution. A study of the influence of the number of design parameters is performed and it is observed that the EFG can give better results with a smaller number of design parameters than is possible with traditional methods. Copyright © 2001 John Wiley & Sons, Ltd. [source] Sensitivity analysis of neural network parameters to improve the performance of electricity price forecastingINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2009Paras Mandal Abstract This paper presents a sensitivity analysis of neural network (NN) parameters to improve the performance of electricity price forecasting. The presented work is an extended version of previous works done by authors to integrate NN and similar days (SD) method for predicting electricity prices. Focus here is on sensitivity analysis of NN parameters while keeping the parameters same for SD to forecast day-ahead electricity prices in the PJM market. Sensitivity analysis of NN parameters include back-propagation learning set (BP-set), learning rate (,), momentum (,) and NN learning days (dNN). The SD parameters, i.e. time framework of SD (d=45 days) and number of selected similar price days (N=5) are kept constant for all the simulated cases. Forecasting performance is carried out by choosing two different days from each season of the year 2006 and for which, the NN parameters for the base case are considered as BP-set=500, ,=0.8, ,=0.1 and dNN=45 days. Sensitivity analysis has been carried out by changing the value of BP-set (500, 1000, 1500); , (0.6, 0.8, 1.0, 1.2), , (0.1, 0.2, 0.3) and dNN (15, 30, 45 and 60 days). The most favorable value of BP-set is first found out from the sensitivity analysis followed by that of , and ,, and based on which the best value of dNN is determined. Sensitivity analysis results demonstrate that the best value of mean absolute percentage error (MAPE) is obtained when BP-set=500, ,=0.8, ,=0.1 and dNN=60 days for winter season. For spring, summer and autumn, these values are 500, 0.6, 0.1 and 45 days, respectively. MAPE, forecast mean square error and mean absolute error of reasonably small value are obtained for the PJM data, which has correlation coefficient of determination (R2) of 0.7758 between load and electricity price. Numerical results show that forecasts generated by developed NN model based on the most favorable case are accurate and efficient. Copyright © 2008 John Wiley & Sons, Ltd. [source] Life cycle assessment of a PPV plant applied to an existing SUW management systemINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 5 2003Francesco Di Maria Abstract The huge amount of wastes produced by modern and developed countries involves important aspects of economical, social and technical fields and also of the environment. For this reason, different technologies have been proposed for trying to reduce the impact of waste management and disposal. Generally waste management system consists of different steps like selective collection, recycling and reuse operation, energy recovery from waste and landfilling. A new technology proposed for thermal waste treatment is the plasma pyrolysis vetrification (PPV). This system seems to have interesting perspective due to the possibility of thermal treatment of dangerous slag or waste producing inactivate vetrified substances that can be landfilled or used as building materials with no impact on the environment. In this study, the effect of the application of a PPV plant on an existing waste management system was evaluated with a life cycle assessment (LCA) analysis. All the activities connected to the existing system have been carefully analysed by collecting a large quantity of experimental data. Some assumptions have been made, in particular, on the PPV plant performance. LCA analysis results illustrate how the environmental benefits arising from the adoption of the new technology, concerns only few aspects of the whole system. Copyright © 2003 John Wiley & Sons, Ltd. [source] Can Basic Individual Differences Shed Light on the Construct Meaning of Assessment Center Evaluations?INTERNATIONAL JOURNAL OF SELECTION AND ASSESSMENT, Issue 1 2003J. M. Collins The construct meaning of assessment center evaluations is an important unresolved issue in I/O psychology. This study hypothesized that Cognitive Ability and personality traits are primary correlates of evaluators' overall assessment ratings (OARs). Meta,analysis results based on 65 correlations indicate the following mean construct,level correlations with OARs: .67 for Cognitive Ability, .50 for Extraversion, .35 for Emotional Stability, .25 for Openness, and .17 for Agreeableness; yielding a multiple R of .84. These findings support our hypothesis and cast light on the construct meaning of assessment center evaluations. [source] Synthesis and characterization of a cured epoxy resin with a benzoxazine monomer containing allyl groupsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Shiao-Wei Kuo Abstract Vinyl-terminated benzoxazine (VB-a), which can be polymerized through ring-opening polymerization, was synthesized through the Mannich condensation of bisphenol A, formaldehyde, and allylamine. This VB-a monomer was then blended with epoxy resin and then concurrently thermally cured to form an epoxy/VB-a copolymer network. To understand the curing kinetics of this epoxy/VB-a copolymer, dynamic differential scanning calorimetry measurements were performed by the Kissinger and Flynn,Wall,Ozawa methods. Fourier transform infrared (FTIR) analyses revealed the presence of thermal curing reactions and hydrogen-bonding interactions of the epoxy/VB-a copolymers. Meanwhile, a significant enhancement of the ring-opening and allyl polymerizations of the epoxy was observed. For these interpenetrating polymer networks, dynamic mechanical analysis and thermogravimetric analysis results indicate that the thermal properties increased with increasing VB-a content in the epoxy/VB-a copolymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Syntheses and properties of cross-linked polymers from functionalized triglyceridesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008Hui-Ping Zhao Abstract A number of functionalized triglycerides were synthesized from glyceryl trioleoate via epoxidation followed by reduction to give glyceryl tris(9-hydroxy)trioleoate (a triol) or hydrolytic ring opening to obtain glyceryl tris(9,10-dihydroxy)trioleoate (a hexaol). A selective monoepoxidation reaction of glyceryl trioleoate was also carried out and the resulting monoepoxide was hydrolyzed to give glyceryl 9,10-dihydroxytrioleoate (a diol). Glyceryl tris(9-hydroxy)trioleoate was brominated followed by displacement with sodium azide and reduction to give glyceryl tris(9-amino)trioleoate (a triamine) and glyceryl tris[9-(N -isopropylamino)]trioleoate. These functionalized triglycerides were crosslinked with 1,4-phenylene diisocyanate. The crosslinked polymers exhibit thermoset characteristics. Thermal analysis results suggest that the polymers are in amorphous states, and their thermal stability was significantly affected by crosslink degree. The crosslinked polymer derived from the diol retained 56% of its weight at 408°C, whereas the polymers derived from the aforementioned hexaol with higher crosslink degree retained only 36% of the original weight. Glass transition temperatures of these polymers range from ,1.0°C to 10.2°C. The thermal stable polymer, 12, derived from the aforementioned diol exhibits a linear viscoelastic character and can be used as thermoplastics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Monitoring cascade processes using VSI EWMA control chartsJOURNAL OF CHEMOMETRICS, Issue 9 2009Su-Fen Yang Abstract The paper considers the variables process control scheme for cascade process. We construct variable sampling interval (VSI) EWMA and EWMA control charts to effectively monitor the input variable and the output variable produced by a cascade process. Numerical analysis results demonstrate that the performance of the VSI control charts is much better than the fixed sampling interval (FSI) control charts in detecting small and median shifts. Copyright © 2009 John Wiley & Sons, Ltd. [source] Using patient-focused research in evaluating treatment outcome in private practiceJOURNAL OF CLINICAL PSYCHOLOGY, Issue 10 2002Ted P. Asay The increasing emphasis on therapist accountability and empirical demonstration of psychotherapeutic treatment effectiveness points to the need for practicing therapists to integrate treatment evaluation methods into routine clinical practice. Unfortunately, most private practitioners have little involvement in carrying out evaluation procedures. In this study we demonstrate how patient-focused research was used to track the progress and outcome of patients seen by a clinical psychologist in private practice. Twenty-nine adults and 40 children/adolescents were evaluated on a weekly basis to assess the number of sessions required to reach improvement (reliable change) and recovery (clinically significant change). Dose-response survival analysis results indicated that 50% of adults reached clinically significant change in 54 sessions, and 50% of youth met the same standard in 14 sessions. These results were compared with outcome in large-scale studies. Implications of this study for integrating treatment evaluation methods into clinical practice are discussed. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 1213,1225, 2002. [source] The Use of Instant Messaging in Working Relationship Development: A Case StudyJOURNAL OF COMPUTER-MEDIATED COMMUNICATION, Issue 4 2005Hee-Kyung Cho This article examines how Instant Messaging (IM) systems help employees of a Korean organization improve their relationships with their coworkers within and across organizational boundaries,within departments, between departments, and outside the organization. We briefly review literature about IM in developing working relationships and build our research questions. We then provide data analysis results based on a survey and structured interviews. Subsequently, in an exploratory case study of two individuals, we extend the analysis of departmental boundaries by including hierarchical levels, job profiles, and different communication purposes. Quantitative Social Network Analysis and visualization are used to analyze the communication pattern of the two individuals. [source] Alkaline hydrolysis of cinnamaldehyde to benzaldehyde in the presence of ,-cyclodextrinAICHE JOURNAL, Issue 2 2010Hongyan Chen Abstract A facile, novel, and cost-effective alkaline hydrolysis process of cinnamaldehyde to benzaldehyde under rather mild conditions has been investigated systematically in the presence of ,-cyclodextrin (,-CD), with water as the only solvent. ,-CD could form inclusion complex with cinnamaldehyde in water, with molar ratio of 1:1, so as to promote the reaction selectivity. The complex has been investigated experimentally and with computational methods. 1H-NMR, ROESY, UV,Vis, and FTIR have been utilized to analyze the inclusion complex. It shows that the equilibrium constant for inclusion (Ka) is 363 M,1, and the standard Gibbs function for the reaction, ,,G (298 K), is ,14.6 kJ mol,1. In addition, the structures of the proposed inclusion compounds were optimized with hybrid ONIOM theory. Benzaldehyde could be obtained at an yield of 42% under optimum conditions [50°C, 18 h, 2% NaOH (w/v), cinnamaldehyde:,-CD (molar ratio) = 1:1]. To explain the experimental data, NMR, FTIR, and elemental analysis results were used to determine the main reaction by-product 1-naphthalenemethanol. A feasible reaction mechanism including the retro-Aldol condensation of cinnamaldehyde and the Aldol condensation of acetaldehyde and cinnamaldehyde in basic aqueous ,-CD solution has been proposed. The calculated activation energy for the reaction was 45.27 kJ mol,1 by initial concentrations method. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Role of Mn of PEG in the morphology and properties of electrospun PEG/CA composite fibers for thermal energy storageAICHE JOURNAL, Issue 3 2009Changzhong Chen Abstract As an aim toward developing novel class of form-stable polymer-matrix phase change materials for thermal energy storage, ultrafine composite fibers based on cellulose acetate and polyethylene glycol (PEG) with five different molecular weight (Mn) grades were prepared by electrospinning. The effects of Mn of PEG on morphology, thermal properties and mechanical properties of the composite fibers were studied by field emission scanning electron microscopy, differential scanning calorimetry, and tensile testing, respectively. It was found that the composite fibers were smooth and cylindrical shape, with the average diameters ranging from about 1000 to 1750 nm which increased with Mn of PEG. Thermal analysis results showed that the composite fibers imparted balanced thermal storage and release properties in different temperature ranges with the variation of Mn of PEG. Thermal cycling test indicated that the prepared composites had excellent thermal stability and reliability even they were subjected to 100 heating-cooling thermal cycles. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Functional colloidal particles stabilized by layered silicate with hydrophilic face and hydrophobic polymer brushesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2009Yani Wu Abstract In this study, we describe a new strategy for producing narrowly dispersed functional colloidal particles stabilized by a nanocomposite with hydrophilic clay faces and hydrophobic polystyrene (PS) brushes on the edges. This method involves preparation of polymer brushes on the edges of clay layers and Pickering suspension polymerization of styrene in the presence of the nanocomposites. PS brushes on the edges of clay layers were prepared by atom transfer radical polymerization. X-ray diffraction and thermogravimetric analysis results indicated that PS chains were grafted to the edges of clay platelets. Transmission electron microscope results showed that different morphologies of clay-PS particles could be obtained in different solvents. In water, clay-PS particles aggregated together, in which PS chains collapsed forming nanosized hydrophobic domains and hydrophilic clay faces stayed in aqueous phase. In toluene, clay-PS particles formed face-to-face structure. Narrowly dispersed PS colloidal particles stabilized by clay-PS were prepared by suspension polymerization. Because of the negatively charged clay particles on the surface, the zeta potential of the PS colloidal particles was negative. Positively charged poly(2-vinyl pyridine) (P2VP) chains were adsorbed to the surface of PS colloidal particles in aqueous solution at a low pH value, and gold nanoparticles were prepared in P2VP brushes. Such colloidal particles may find important applications in a variety of fields including waterborne adhesives, paints, catalysis of chemical reactions, and protein separation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1535,1543, 2009 [source] Lightly crosslinked, mesomorphic networks obtained through the reaction of dimeric, liquid-crystalline epoxy,imine monomers and heptanedioic acidJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2006David Ribera Abstract We reacted various dimeric, liquid-crystalline epoxy,imine monomers, differing in the length of the central aliphatic spacer or the dipolar moments, with heptanedioic acid. The resulting systems showed a liquid-crystalline phase in some cases, depending on the dimer and on the reaction conditions. The systems were characterized with respect to their mesomorphic properties and then were submitted to dynamic mechanical thermal analysis in both fixed-frequency and frequency-sweep modes in the shear sandwich configuration. The arrangement in the liquid-crystalline phase seemed to be mainly affected both by the polarization of the mesogen and by the reaction temperature, which favored the liquid-crystalline arrangement when it was lying in the range of stability of the dimer mesophase. In agreement with other recent literature data, dynamic mechanical thermal analysis results suggested that the presence of the mesogen directly incorporated into the main chain increased the lifetimes of the elastic modes both in the isotropic phase and in the liquid-crystalline phase with respect to side-chain liquid-crystalline elastomers and that the time,temperature superposition principle did not hold through the liquid-crystalline-to-isotropic transition. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44:6270,6286, 2006 [source] Comparative Entrepreneurial Cognitions and Lagging Russian New Venture Formation: A Tale of Two Countries,JOURNAL OF SMALL BUSINESS MANAGEMENT, Issue 4 2008Kristie W. Seawright Changes in Russian government and economic systems over the last 15 years led to expectations of increased entrepreneurial activity. Yet potential entrepreneurs are deciding to venture at a much lower rate than anticipated. New venture creation in Russia is occurring at a rate that is considerably lower than that of the United States and Western Europe. This research examines cognitive similarities and differences among Russian and U.S. entrepreneurs and nonentrepreneurs to find a possible explanation. Multivariate analysis of variance and multiple discriminant analysis results found similarities between U.S. and Russian experts and U.S. and Russian novices with respect to arrangements, willingness, and ability scripts, but differences in these scripts were found between experts and novices, particularly in Russia. Implications for entrepreneurship cognition research and public policy are discussed. [source] | ||||||||||||||||||||||||||||||||||