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Sample records for model synthesis method

  1. Computational method and system for modeling, analyzing, and optimizing DNA amplification and synthesis

    Science.gov (United States)

    Vandersall, Jennifer A.; Gardner, Shea N.; Clague, David S.

    2010-05-04

    A computational method and computer-based system of modeling DNA synthesis for the design and interpretation of PCR amplification, parallel DNA synthesis, and microarray chip analysis. The method and system include modules that address the bioinformatics, kinetics, and thermodynamics of DNA amplification and synthesis. Specifically, the steps of DNA selection, as well as the kinetics and thermodynamics of DNA hybridization and extensions, are addressed, which enable the optimization of the processing and the prediction of the products as a function of DNA sequence, mixing protocol, time, temperature and concentration of species.

  2. A fast method for Stokes profile synthesis. Radiative transfer modeling for ZDI and Stokes profile inversion

    Science.gov (United States)

    Carroll, T. A.; Kopf, M.; Strassmeier, K. G.

    2008-09-01

    Context: The major challenges for a fully polarized radiative transfer driven approach to Zeeman-Doppler imaging are still the enormous computational requirements. In every cycle of the iterative interplay between the forward process (spectral synthesis) and the inverse process (derivative based optimization) the Stokes profile synthesis requires several thousand evaluations of the polarized radiative transfer equation for a given stellar surface model. Aims: To cope with these computational demands and to allow for the incorporation of a full Stokes profile synthesis into Doppler- and Zeeman-Doppler imaging applications as well as into large scale solar Stokes profile inversions, we present a novel fast and accurate synthesis method for calculating local Stokes profiles. Methods: Our approach is based on artificial neural network models, which we use to approximate the complex non-linear mapping between the most important atmospheric parameters and the corresponding Stokes profiles. A number of specialized artificial neural networks, are used to model the functional relation between the model atmosphere, magnetic field strength, field inclination, and field azimuth, on one hand and the individual components (I,Q,U,V) of the Stokes profiles, on the other hand. Results: We performed an extensive statistical evaluation and show that our new approach yields accurate local as well as disk-integrated Stokes profiles over a wide range of atmospheric conditions. The mean rms errors for the Stokes I and V profiles are well below 0.2% compared to the exact numerical solution. Errors for Stokes Q and U are in the range of 1%. Our approach does not only offer an accurate approximation to the LTE polarized radiative transfer it, moreover, accelerates the synthesis by a factor of more than 1000.

  3. A basis for designing digital library maturity model: Meta-synthesis method application

    Directory of Open Access Journals (Sweden)

    Fatemeh Sheikhshoaei

    2017-06-01

    Full Text Available Digital Library (DL development is faced with many challenges which cannot be overcome all at once. In such cases which are so complex, maturity models are utilized. In a maturity model, features of a phenomenon are classified into few levels so that improving or realizing the features of each level is the prerequisite of going to the next level. DL can also be approached by maturity model more efficiently and effectively. Since the maturity model for DL has not been designed yet, first, a literature review of the DL and maturity models using a qualitative approach and meta-synthesis method was done. According to the findings of the literature review, the maturity characteristics of DL are proposed to be a basis for designing DL maturity model. Since the concept of maturity and DL is extensive and has several dimensions, meta-synthesis has been found as a suitable method for comprehensive integration of the models offered in other areas with the existing literature in the field of DL based on their interpretation. To do so, 68 papers (38 in the field of DL and 30 in the field of maturity models in various fields were selected from the available resources. By analyzing these papers, three categories, seven concepts, and 35 codes obtained as DL maturity features. Among these findings, the focuses of previous studies have been on the use of software/ hardware systems as supporter and enabler of DL and the DL content. The found features, in addition to be a basis for designing of digital library model, can be a tool in the hands of project managers of DL for assessing the status of their projects and planning to achieve higher levels of maturity.

  4. Modelling and Simulation on Multibody Dynamics for Vehicular Cold Launch Systems Based on Subsystem Synthesis Method

    Science.gov (United States)

    Panyun, YAN; Guozhu, LIANG; Yongzhi, LU; Zhihui, QI; Xingdou, GAO

    2017-12-01

    The fast simulation of the vehicular cold launch system (VCLS) in the launch process is an essential requirement for practical engineering applications. In particular, a general and fast simulation model of the VCLS will help the designer to obtain the optimum scheme in the initial design phase. For these purposes, a system-level fast simulation model was established for the VCLS based on the subsystem synthesis method. Moreover, a comparison of the load of a seven-axis VCLS on the rigid ground through both theoretical calculations and experiments was carried out. It was found that the error of the load of the rear left outrigger is less than 7.1%, and the error of the total load of all the outriggers is less than 2.8%. Moreover, time taken for completion of the simulation model is only 9.5 min, which is 5% of the time taken by conventional algorithms.

  5. MODEL AND METHOD FOR SYNTHESIS OF PROJECT MANAGEMENT METHODOLOGY WITH FUZZY INPUT DATA

    Directory of Open Access Journals (Sweden)

    Igor V. KONONENKO

    2016-02-01

    Full Text Available Literature analysis concerning the selection or creation a project management methodology is performed. Creating a "complete" methodology is proposed which can be applied to managing projects with any complexity, various degrees of responsibility for results and different predictability of the requirements. For the formation of a "complete" methodology, it is proposed to take the PMBOK standard as the basis, which would be supplemented by processes of the most demanding plan driven and flexible Agile Methodologies. For each knowledge area of the PMBOK standard, The following groups of processes should be provided: initiation, planning, execution, reporting, and forecasting, controlling, analysis, decision making and closing. The method for generating a methodology for the specific project is presented. The multiple criteria mathematical model and method aredeveloped for the synthesis of methodology when initial data about the project and its environment are fuzzy.

  6. A general mixed boundary model reduction method for component mode synthesis

    NARCIS (Netherlands)

    Voormeeren, S.N.; Van der Valk, P.L.C.; Rixen, D.J.

    2010-01-01

    A classic issue in component mode synthesis (CMS) methods is the choice for fixed or free boundary conditions at the interface degrees of freedom (DoF) and the associated vibration modes in the components reduction base. In this paper, a novel mixed boundary CMS method called the “Mixed

  7. [Interpretative method as a synthesis of explicative, teleologic and analogic models].

    Science.gov (United States)

    Yáñez Cortés, R

    1980-06-01

    To establish the basis of the interpretative method is congruous with finding a solid basis--epistemologically speaking--to the analytic theory. This basis would be the means to transform this theory into a real science with its necessary adecuation among method, act and object of knowledge. It is only from a scientific stand that the psychoanalytic theory will be able to face successfully the reductionisms that menace it, be it the biologist-naturalism with its explanations of the psychic phenomena by means of mechanisms and biologic models or be it the speculative ideologies with their nucleus of technical praxis which make it impossible for the social-factic sciences to become real sciences. We propose as interpretative method the union of two models: the teleologic one which makes possible the appearance of intelligible, contingent and variable explanations between an antecedent and a consequent on one side, and on the other, the analogic model with its two moments: the comparative and the symbolic one. These moments makes possible the comparison and the union between antecedent and consequent baring in mind the "natural" ambiguity of the subject-object in question. The principal objective of the method--as a regulative idea in the Kantian sense--would be the search of univocity as regards the choice of one and only one sense from all the possible senses that "explain" the motive relationship or motive-end relationship in order to make the interpretation scientific. This status of scientificity should obey the rules of explanation: that the interpretations be derived effectively from the presupposed theory, that they really explain what they claim to explain, that they are not contradictory or contrary in the same ontologic level. We postulate that the synthesis of the two mentioned models, the teleologic-explanative and the analogic one allows us to find a possibility to make clear the "dark" sense of the noun interpretation and in this way the factibility of

  8. Synthesis of Numerical Methods for Modeling Wave Energy Converter-Point Absorbers: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Yu, Y. H.

    2012-05-01

    During the past few decades, wave energy has received significant attention among all ocean energy formats. Industry has proposed hundreds of prototypes such as an oscillating water column, a point absorber, an overtopping system, and a bottom-hinged system. In particular, many researchers have focused on modeling the floating-point absorber as the technology to extract wave energy. Several modeling methods have been used such as the analytical method, the boundary-integral equation method, the Navier-Stokes equations method, and the empirical method. However, no standardized method has been decided. To assist the development of wave energy conversion technologies, this report reviews the methods for modeling the floating-point absorber.

  9. Using logic model methods in systematic review synthesis: describing complex pathways in referral management interventions.

    Science.gov (United States)

    Baxter, Susan K; Blank, Lindsay; Woods, Helen Buckley; Payne, Nick; Rimmer, Melanie; Goyder, Elizabeth

    2014-05-10

    There is increasing interest in innovative methods to carry out systematic reviews of complex interventions. Theory-based approaches, such as logic models, have been suggested as a means of providing additional insights beyond that obtained via conventional review methods. This paper reports the use of an innovative method which combines systematic review processes with logic model techniques to synthesise a broad range of literature. The potential value of the model produced was explored with stakeholders. The review identified 295 papers that met the inclusion criteria. The papers consisted of 141 intervention studies and 154 non-intervention quantitative and qualitative articles. A logic model was systematically built from these studies. The model outlines interventions, short term outcomes, moderating and mediating factors and long term demand management outcomes and impacts. Interventions were grouped into typologies of practitioner education, process change, system change, and patient intervention. Short-term outcomes identified that may result from these interventions were changed physician or patient knowledge, beliefs or attitudes and also interventions related to changed doctor-patient interaction. A range of factors which may influence whether these outcomes lead to long term change were detailed. Demand management outcomes and intended impacts included content of referral, rate of referral, and doctor or patient satisfaction. The logic model details evidence and assumptions underpinning the complex pathway from interventions to demand management impact. The method offers a useful addition to systematic review methodologies. PROSPERO registration number: CRD42013004037.

  10. The application of the large particles method of numerical modeling of the process of carbonic nanostructures synthesis in plasma

    Science.gov (United States)

    Abramov, G. V.; Gavrilov, A. N.

    2018-03-01

    The article deals with the numerical solution of the mathematical model of the particles motion and interaction in multicomponent plasma by the example of electric arc synthesis of carbon nanostructures. The high order of the particles and the number of their interactions requires a significant input of machine resources and time for calculations. Application of the large particles method makes it possible to reduce the amount of computation and the requirements for hardware resources without affecting the accuracy of numerical calculations. The use of technology of GPGPU parallel computing using the Nvidia CUDA technology allows organizing all General purpose computation on the basis of the graphical processor graphics card. The comparative analysis of different approaches to parallelization of computations to speed up calculations with the choice of the algorithm in which to calculate the accuracy of the solution shared memory is used. Numerical study of the influence of particles density in the macro particle on the motion parameters and the total number of particle collisions in the plasma for different modes of synthesis has been carried out. The rational range of the coherence coefficient of particle in the macro particle is computed.

  11. Synthesis gas method and apparatus

    Science.gov (United States)

    Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.; Rosen, Lee J.; Christie, Gervase Maxwell; Wilson, Jamie R.; Kosowski, Lawrence W.; Robinson, Charles

    2013-01-08

    A method and apparatus for producing a synthesis gas product having one or more oxygen transport membrane elements thermally coupled to one or more catalytic reactors such that heat generated from the oxygen transport membrane element supplies endothermic heating requirements for steam methane reforming reactions occurring within the catalytic reactor through radiation and convention heat transfer. A hydrogen containing stream containing no more than 20 percent methane is combusted within the oxygen transport membrane element to produce the heat and a heated combustion product stream. The heated combustion product stream is combined with a reactant stream to form a combined stream that is subjected to the reforming within the catalytic reactor. The apparatus may include modules in which tubular membrane elements surround a central reactor tube.

  12. Instrument Modeling and Synthesis

    Science.gov (United States)

    Horner, Andrew B.; Beauchamp, James W.

    During the 1970s and 1980s, before synthesizers based on direct sampling of musical sounds became popular, replicating musical instruments using frequency modulation (FM) or wavetable synthesis was one of the “holy grails” of music synthesis. Synthesizers such as the Yamaha DX7 allowed users great flexibility in mixing and matching sounds, but were notoriously difficult to coerce into producing sounds like those of a given instrument. Instrument design wizards practiced the mysteries of FM instrument design.

  13. “Best fit” framework synthesis: refining the method

    Science.gov (United States)

    2013-01-01

    Background Following publication of the first worked example of the “best fit” method of evidence synthesis for the systematic review of qualitative evidence in this journal, the originators of the method identified a need to specify more fully some aspects of this particular derivative of framework synthesis. Methods and Results We therefore present a second such worked example in which all techniques are defined and explained, and their appropriateness is assessed. Specified features of the method include the development of new techniques to identify theories in a systematic manner; the creation of an a priori framework for the synthesis; and the “testing” of the synthesis. An innovative combination of existing methods of quality assessment, analysis and synthesis is used to complete the process. This second worked example was a qualitative evidence synthesis of employees’ views of workplace smoking cessation interventions, in which the “best fit” method was found to be practical and fit for purpose. Conclusions The method is suited to producing context-specific conceptual models for describing or explaining the decision-making and health behaviours of patients and other groups. It offers a pragmatic means of conducting rapid qualitative evidence synthesis and generating programme theories relating to intervention effectiveness, which might be of relevance both to researchers and policy-makers. PMID:23497061

  14. Optimization of Catalytic Ozonation Process for Formaldehyde Mineralization from Synthetic Wastewater by Fe/MgO Nanoparticles Synthesis by Sol-Gel Method by Response Surface Model

    Directory of Open Access Journals (Sweden)

    Ghorban Asgari

    2014-09-01

    Full Text Available Background: Design experiment stages of formalin mineralization process by center composition design (CCD cause ease of work, reducing the number of samples, increasing the accuracy of optimized conditions and the interaction parameters determined during the process. The aim of this study was optimization of catalytic ozonation process for formaldehyde mineralization from synthetic wastewater by Fe/MgO nanoparticles synthesis by sol-gel method by response surface model. Methods: This experimental study was conducted in a semi-batch reactor, using a RSM by taking 3 factors in the final stage of pH (7-9, reaction time (10-20 min and catalyst dose (1.1-1.3 g/L was investigated. Synthesis of nanoparticles was done by sol-gel method. The results were analyzed by Design Expert 7.0.1 software. Results: The results showed that the process was dependent on the parameters studied and changing each parameter, affected the process efficiency and other parameters. The optimum conditions predicted for the process was 86.51% of mineralization efficiency. Optimum condition included pH=8.82, reaction time of 20 minute and catalyst dose of 1.3 g/L. The correlation coefficient for the process was determined 0.91. Conclusion: Using a statistical model could reduce the number of experiments, the accuracy and the prediction process. The catalytic ozonation process has the ability to remove formaldehyde with high efficiency and the process was environmental friendly.

  15. Methods of synthesis of deuterium labelled lipids

    International Nuclear Information System (INIS)

    Bragina, N.A.; Chupin, V.V.

    1997-01-01

    Methods for synthesis of deuterium-labelled hydrophobic and hydrophilic lipid molecules and ways of obtaining selectively and completely deuterized phospholipids and their analogues are considered. The deuterium-labelled lipids are used for studies on structural organization and functioning of biological membranes, including studies with the NMP and neutron-diffraction methods of lipid-lipid and lipid-protein interactions

  16. Nanocomposites: Synthesis, characterization and its application to removal azo dyes using ultrasonic assisted method: Modeling and optimization.

    Science.gov (United States)

    Porhemmat, Sima; Ghaedi, Mehrorang; Rezvani, Ali Reza; Azqhandi, Mohammad Hossein Ahmadi; Bazrafshan, Ali Akbar

    2017-09-01

    S-doped and Cu- and Co-doped TiO 2 was synthesized by a sol-gel method and characterized by FE-SEM, XRD, EDX and FTIR. The Co/Cu/S-TiO 2 nanocomposite loaded on the activated carbon as new nanoadsorbent was used for simultaneous removal of methylene blue (MB) and sunset yellow (SY) from aqueous solution by ultrasonic-assisted adsorption method. In this work, central composite design (CCD) and adaptive neuro-fuzzy inference system (ANFIS) as a support tool for examining data and making prediction are used to recognize and predict the removal percentage in MB and SY dye solution of different concentrations. The predictive capabilities of CCD and ANFIS are compared in terms of square correlation coefficient (R 2 ), root mean square error (RMSE), mean absolute error (MAE) and absolute average deviation (AAD) against the empirical data. It is found that the ANFIS model shows the better prediction accuracy than the CCD model. In addition to, the optimization of ultrasound-assisted simultaneous removal of methylene blue (MB) and sunset yellow (SY) on the Co/Cu/S-TiO 2 /AC nanocomposite by response surface methodology (RSM) for the optimization of the process variables, such as MB and SY concentrations, Co/Cu/S-TiO 2 /AC nanocomposite dose and sonication time, was investigated. Various isotherm and kinetic models were used in the experimental data. The results revealed that the langmuir isotherm and pseudo-second-order model had a better correlation than the other models. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Greener Methods for Aspirin Synthesis

    OpenAIRE

    Barilone, Jessica

    2013-01-01

    In this semester long study, I used microwave irradiation to synthesize aspirin. I compared this method to a traditional method that utilizes a strong acid. I compared the percent yield and the purity of the methods to pure aspirin. 

  18. Comparison of interpolation and approximation methods for optical freeform synthesis

    Science.gov (United States)

    Voznesenskaya, Anna; Krizskiy, Pavel

    2017-06-01

    Interpolation and approximation methods for freeform surface synthesis are analyzed using the developed software tool. Special computer tool is developed and results of freeform surface modeling with piecewise linear interpolation, piecewise quadratic interpolation, cubic spline interpolation, Lagrange polynomial interpolation are considered. The most accurate interpolation method is recommended. Surface profiles are approximated with the square least method. The freeform systems are generated in optical design software.

  19. Synthesis of hydroxyapatite nanoparticles by Sonochemistry Method

    Energy Technology Data Exchange (ETDEWEB)

    Cota, L.F.; Pereira, L.C. [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil); Licona, K.P.M.; Lunz, J.N.; Ribeiro, A.A. [Instituto Nacional de Tecnologia (DPCM/INT), Rio de Janeiro, RJ (Brazil); Morejon, L. [Universidad de La Habana (UH/BIOMAT), Habana (Cuba). Centro de Biomateriales

    2014-07-01

    bone implant substitute due to a great chemical similarity with the biological calcified tissues. Among synthesis conventional methods, the acoustic cavitation, induced by the sonochemical method, allows formation of nano powders. This work aimed to synthesize HAp nano-sized powders by using CaCl2. 2H2O and Na3PO4. 12H2O as precursors, along with pH and temperature control. The sonochemical method was accomplished by using different amplitudes (20%, 60% e 100%). To optimize the process, another synthesis at 60% ultrasound amplitude was performed, with the use of a peristaltic pump for dripping control. The HAp nano powders achieved were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), BET analysis, Scanning Electron Microscope/Field Emission Gun (SEM/FEG) combined with EDS. The results indicated the influence of the sonochemical methodology and drip controlling, on the chemical composition, crystallinity and nanoparticles morphology. (author)

  20. Synthesis of hydroxyapatite nanoparticles by Sonochemistry Method

    International Nuclear Information System (INIS)

    Cota, L.F.; Pereira, L.C.; Licona, K.P.M.; Lunz, J.N.; Ribeiro, A.A.; Morejon, L.

    2014-01-01

    bone implant substitute due to a great chemical similarity with the biological calcified tissues. Among synthesis conventional methods, the acoustic cavitation, induced by the sonochemical method, allows formation of nano powders. This work aimed to synthesize HAp nano-sized powders by using CaCl2. 2H2O and Na3PO4. 12H2O as precursors, along with pH and temperature control. The sonochemical method was accomplished by using different amplitudes (20%, 60% e 100%). To optimize the process, another synthesis at 60% ultrasound amplitude was performed, with the use of a peristaltic pump for dripping control. The HAp nano powders achieved were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), BET analysis, Scanning Electron Microscope/Field Emission Gun (SEM/FEG) combined with EDS. The results indicated the influence of the sonochemical methodology and drip controlling, on the chemical composition, crystallinity and nanoparticles morphology. (author)

  1. Simple Synthesis Method for Alumina Nanoparticle

    OpenAIRE

    Daniel Damian; Florentina Cziple; Adina Segneanu; Ioan Grozescu

    2017-01-01

    Globally, the human population steady increase, expansion of urban areas, excessive industrialization including in agriculture, caused not only decrease to depletion of non-renewable resources, a rapid deterioration of the environment with negative impact on water quality, soil productivity and of course quality of life in general. This paper aims to prepare size controlled nanoparticles of aluminum oxide using a simple synthesis method. The morphology and dimensions of n...

  2. Diagnosis, Synthesis and Analysis of Probabilistic Models

    NARCIS (Netherlands)

    Han, Tingting

    2009-01-01

    This dissertation considers three important aspects of model checking Markov models: diagnosis — generating counterexamples, synthesis — providing valid parameter values and analysis — verifying linear real-time properties. The three aspects are relatively independent while all contribute to

  3. Synthesis method of asymmetric gold particles.

    Science.gov (United States)

    Jun, Bong-Hyun; Murata, Michael; Hahm, Eunil; Lee, Luke P

    2017-06-07

    Asymmetric particles can exhibit unique properties. However, reported synthesis methods for asymmetric particles hinder their application because these methods have a limited scale and lack the ability to afford particles of varied shapes. Herein, we report a novel synthetic method which has the potential to produce large quantities of asymmetric particles. Asymmetric rose-shaped gold particles were fabricated as a proof of concept experiment. First, silica nanoparticles (NPs) were bound to a hydrophobic micro-sized polymer containing 2-chlorotritylchloride linkers (2-CTC resin). Then, half-planar gold particles with rose-shaped and polyhedral structures were prepared on the silica particles on the 2-CTC resin. Particle size was controlled by the concentration of the gold source. The asymmetric particles were easily cleaved from the resin without aggregation. We confirmed that gold was grown on the silica NPs. This facile method for synthesizing asymmetric particles has great potential for materials science.

  4. Simple Synthesis Method for Alumina Nanoparticle

    Directory of Open Access Journals (Sweden)

    Daniel Damian

    2017-11-01

    Full Text Available Globally, the human population steady increase, expansion of urban areas, excessive industrialization including in agriculture, caused not only decrease to depletion of non-renewable resources, a rapid deterioration of the environment with negative impact on water quality, soil productivity and of course quality of life in general. This paper aims to prepare size controlled nanoparticles of aluminum oxide using a simple synthesis method. The morphology and dimensions of nanomaterial was investigated using modern analytical techniques: SEM/EDAX and XRD spectroscopy.

  5. Advances in organometallic synthesis with mechanochemical methods.

    Science.gov (United States)

    Rightmire, Nicholas R; Hanusa, Timothy P

    2016-02-14

    Solvent-based syntheses have long been normative in all areas of chemistry, although mechanochemical methods (specifically grinding and milling) have been used to good effect for decades in organic, and to a lesser but growing extent, inorganic coordination chemistry. Organometallic synthesis, in contrast, represents a relatively underdeveloped area for mechanochemical research, and the potential benefits are considerable. From access to new classes of unsolvated complexes, to control over stoichiometries that have not been observed in solution routes, mechanochemical (or 'M-chem') approaches have much to offer the synthetic chemist. It has already become clear that removing the solvent from an organometallic reaction can change reaction pathways considerably, so that prediction of the outcome is not always straightforward. This Perspective reviews recent developments in the field, and describes equipment that can be used in organometallic synthesis. Synthetic chemists are encouraged to add mechanochemical methods to their repertoire in the search for new and highly reactive metal complexes and novel types of organometallic transformations.

  6. Usage of modal synthesis method with condensation in rotor

    Directory of Open Access Journals (Sweden)

    Zeman V.

    2008-11-01

    Full Text Available The paper deals with mathematical modelling of vibration and modal analysis of rotors composed of a flexible shaft and several flexible disks. The shaft is modelled as a one dimensional continuum whereon flexible disks modelled as a three dimensional continuum are rigid mounted to shaft. The presented approach allows to introduce continuously distributed centrifugal and gyroscopic effects. The finite element method was used for shaft and disks discretization. The modelling of such flexible multi-body rotors with large DOF number is based on the system decomposition into subsystems and on the modal synthesis method with condensation. Lower vibration mode shapes of the mutually uncoupled and non-rotating subsystems are used for creation of the rotor condensed mathematical model. An influence of the different level of a rotor condensation model on the accuracy of calculated eigenfrequencies and eigenvectors is discussed.

  7. A Synthesis of the Literature on Research Methods Education

    Science.gov (United States)

    Earley, Mark A.

    2014-01-01

    The purpose of this research synthesis is to examine the current research on teaching and learning research methods. The aims are to understand the themes present in the current literature and identify gaps in our understanding of how we teach, and how students learn, research methods. A synthesis of 89 studies generated three themes: (1)…

  8. Digital Sound Synthesis Algorithms: a Tutorial Introduction and Comparison of Methods

    Science.gov (United States)

    Lee, J. Robert

    The objectives of the dissertation are to provide both a compendium of sound-synthesis methods with detailed descriptions and sound examples, as well as a comparison of the relative merits of each method based on ease of use, observed sound quality, execution time, and data storage requirements. The methods are classified under the general headings of wavetable-lookup synthesis, additive synthesis, subtractive synthesis, nonlinear methods, and physical modelling. The nonlinear methods comprise a large group that ranges from the well-known frequency-modulation synthesis to waveshaping. The final category explores computer modelling of real musical instruments and includes numerical and analytical solutions to the classical wave equation of motion, along with some of the more sophisticated time -domain models that are possible through the prudent combination of simpler synthesis techniques. The dissertation is intended to be understandable by a musician who is mathematically literate but who does not necessarily have a background in digital signal processing. With this limitation in mind, a brief and somewhat intuitive description of digital sampling theory is provided in the introduction. Other topics such as filter theory are discussed as the need arises. By employing each of the synthesis methods to produce the same type of sound, interesting comparisons can be made. For example, a struck string sound, such as that typical of a piano, can be produced by algorithms in each of the synthesis classifications. Many sounds, however, are peculiar to a single algorithm and must be examined independently. Psychoacoustic studies were conducted as an aid in the comparison of the sound quality of several implementations of the synthesis algorithms. Other psychoacoustic experiments were conducted to supplement the established notions of which timbral issues are important in the re -synthesis of the sounds of acoustic musical instruments.

  9. Method of production of ammonia synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

    1943-09-10

    In the catalytic synthesis of complicated hydrocarbons from carbon monoxide and hydrogen at normal or slightly increased pressures by the Fischer--Tropsch process, or carried out at higher pressures in some other proposals, the synthesis gas was incompletely transformed. After the conclusion of the synthesis, the residual gas, upon the separation of the liquid constituents, contained, in addition to the unreacted carbon moxoxide and hydrogen, also considerable amounts of methane, carbon dioxide, and nitrogen from the original synthesis gas. This residual gas had been used as fuel. It was, however, pure and contained no sulfur or other catalyst poisons and burning it was considered uneconomical. It was proposed to make better use of it by using it as fuel. It was, however, pure and contained no sulfur or other catalyst poisons and burning it was considered uneconomical. It was proposed to make better use of it by using it as a raw material for the production of synthesis gas by decomposing the methane present in it with steam according to the equation CH/sub 4/ + H/sub 2/O = CO + 3H/sub 2/. This conversion was to be brought about either by a return to the producers or else in special splitting units. Also, it had been found that the residual gas, possibly even in the presence of oxygen compounds, could be conveniently used for the synthesis of ammonia. Several examples of ammonia synthesis were discussed.

  10. Synthesis of nano-sized amorphous boron powders through active dilution self-propagating high-temperature synthesis method

    International Nuclear Information System (INIS)

    Wang, Jilin; Gu, Yunle; Li, Zili; Wang, Weimin; Fu, Zhengyi

    2013-01-01

    Graphical abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed. Highlights: ► Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis method. ► The morphology, particle size and purity of the samples could be effectively controlled via changing the endothermic rate. ► The diluter KBH 4 played an important role in active dilution synthesis of amorphous nano-sized boron powders. ► The active dilution method could be further popularized and become a common approach to prepare various inorganic materials. - Abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method at temperatures ranging from 700 °C to 850 °C in a SHS furnace using Mg, B 2 O 3 and KBH 4 as raw materials. Samples were characterized by X-ray powder diffraction (XRD), Laser particle size analyzer, Fourier transform infrared spectra (FTIR), X-ray energy dispersive spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission TEM (HRTEM). The boron powders demonstrated an average particle size of 50 nm with a purity of 95.64 wt.%. The diluter KBH 4 played an important role in the active dilution synthesis of amorphous nano-sized boron powders. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed

  11. Analysis and synthesis of solutions for the agglomeration process modeling

    Science.gov (United States)

    Babuk, V. A.; Dolotkazin, I. N.; Nizyaev, A. A.

    2013-03-01

    The present work is devoted development of model of agglomerating process for propellants based on ammonium perchlorate (AP), ammonium dinitramide (ADN), HMX, inactive binder, and nanoaluminum. Generalization of experimental data, development of physical picture of agglomeration for listed propellants, development and analysis of mathematical models are carried out. Synthesis of models of various phenomena taking place at agglomeration implementation allows predicting of size and quantity, chemical composition, structure of forming agglomerates and its fraction in set of condensed combustion products. It became possible in many respects due to development of new model of agglomerating particle evolution on the surface of burning propellant. Obtained results correspond to available experimental data. It is supposed that analogical method based on analysis of mathematical models of particular phenomena and their synthesis will allow implementing of the agglomerating process modeling for other types of metalized solid propellants.

  12. Asymmetric synthesis II more methods and applications

    CERN Document Server

    Christmann, Mathias

    2012-01-01

    After the overwhelming success of 'Asymmetric Synthesis - The Essentials', narrating the colorful history of asymmetric synthesis, this is the second edition with latest subjects and authors. While the aim of the first edition was mainly to honor the achievements of the pioneers in asymmetric syntheses, the aim of this new edition was bringing the current developments, especially from younger colleagues, to the attention of students. The format of the book remained unchanged, i.e. short conceptual overviews by young leaders in their field including a short biography of the authors. The growing multidisciplinary research within chemistry is reflected in the selection of topics including metal catalysis, organocatalysis, physical organic chemistry, analytical chemistry, and its applications in total synthesis. The prospective reader of this book is a graduate or undergraduate student of advanced organic chemistry as well as the industrial chemist who wants to get a brief update on the current developments in th...

  13. MFI-molecular sieve membranes:synthesis, characterization and modelling

    OpenAIRE

    Jareman, Fredrik

    2002-01-01

    This work concerns evaluation by permeation measurements and modeling of thin (<2µm) MFI molecular sieve membranes and, to a smaller extent, synthesis of such materials. The membranes have been synthesized on graded a-alumina microfiltration filters using The seed film method. Scanning electron microscopy and x-ray diffraction were used for characterization in addition to permeation measurements. Mathematical models describing membrane flux for real membranes and defect distributions were ...

  14. Two synthesis methods based on cepstral parametrization

    Czech Academy of Sciences Publication Activity Database

    Přibil, Jiří; Madlová, A.

    2002-01-01

    Roč. 11, č. 2 (2002), s. 35-39 ISSN 1210-2512 R&D Projects: GA MŠk OC 258.10; GA ČR GV102/96/K087 Institutional research plan: CEZ:AV0Z2067918 Keywords : speech processing * speech synthesis * signal processing Subject RIV: JD - Computer Applications, Robotics

  15. Model Correction Factor Method

    DEFF Research Database (Denmark)

    Christensen, Claus; Randrup-Thomsen, Søren; Morsing Johannesen, Johannes

    1997-01-01

    The model correction factor method is proposed as an alternative to traditional polynomial based response surface techniques in structural reliability considering a computationally time consuming limit state procedure as a 'black box'. The class of polynomial functions is replaced by a limit...... statebased on an idealized mechanical model to be adapted to the original limit state by the model correction factor. Reliable approximations are obtained by iterative use of gradient information on the original limit state function analogously to previous response surface approaches. However, the strength...... of the model correction factor method, is that in simpler form not using gradient information on the original limit state function or only using this information once, a drastic reduction of the number of limit state evaluation is obtained together with good approximations on the reliability. Methods...

  16. Controller Synthesis using Qualitative Models and Constraints

    OpenAIRE

    Ramamoorthy, Subramanian; Kuipers, Benjamin J

    2004-01-01

    Many engineering systems require the synthesis of global behaviors in nonlinear dynamical systems. Multiple model approaches to control design make it possible to synthesize robust and optimal versions of such global behaviors. We propose a methodology called Qualitative Heterogeneous Control that enables this type of control design. This methodology is based on a separation of concerns between qualitative correctness and quantitative optimization. Qualitative sufficient conditions are derive...

  17. Fe-based Fischer Tropsch Synthesis of biomass-derived syngas: Effect of synthesis method

    Science.gov (United States)

    Khiet Mai; Thomas Elder; Les Groom; James J. Spivey

    2015-01-01

    Two 100Fe/4Cu/4K/6Zn catalysts were prepared using two different methods: coprecipitation or impregnation methods. The effect of the preparation methods on the catalyst structure, catalytic properties, and the conversion of biomass-derived syngas via Fischer–Tropsch synthesis was investigated. Syngas was derived from gasifying Southern pine woodchips and had the...

  18. Silver nanoparticles: Synthesis methods, bio-applications and properties.

    Science.gov (United States)

    Abbasi, Elham; Milani, Morteza; Fekri Aval, Sedigheh; Kouhi, Mohammad; Akbarzadeh, Abolfazl; Tayefi Nasrabadi, Hamid; Nikasa, Parisa; Joo, San Woo; Hanifehpour, Younes; Nejati-Koshki, Kazem; Samiei, Mohammad

    2016-01-01

    Silver nanoparticles size makes wide range of new applications in various fields of industry. Synthesis of noble metal nanoparticles for applications such as catalysis, electronics, optics, environmental and biotechnology is an area of constant interest. Two main methods for Silver nanoparticles are the physical and chemical methods. The problem with these methods is absorption of toxic substances onto them. Green synthesis approaches overcome this limitation. Silver nanoparticles size makes wide range of new applications in various fields of industry. This article summarizes exclusively scalable techniques and focuses on strengths, respectively, limitations with respect to the biomedical applicability and regulatory requirements concerning silver nanoparticles.

  19. An Expedient Method for the Synthesis of Acylhydrazones under ...

    African Journals Online (AJOL)

    A simple, efficient and eco-friendly method for the synthesis of acylhydrazones from acylhydrazides and aldehydes under microwave (MW) irradiation was reported, no solvent and catalyst was used. The method is combined with a combinatorial approach and fourteen novel acylhydrazones were synthesized in excellent ...

  20. Two expedient 'one-pot'methods for synthesis of -aryl- ...

    Indian Academy of Sciences (India)

    Keywords. -aryl--mercaptoketones; anhydrous potassium carbonate; amberlyst-15; chalcones; thia-Michael addition. Abstract. Two expedient one-pot methods have been developed for synthesis of -aryl--mercaptoketones using acetophenones, benzaldehydes and thiols as starting materials. The methods involve ...

  1. Steady Modeling for an Ammonia Synthesis Reactor Based on a Novel CDEAS-LS-SVM Model

    Directory of Open Access Journals (Sweden)

    Zhuoqian Liu

    2014-01-01

    Full Text Available A steady-state mathematical model is built in order to represent plant behavior under stationary operating conditions. A novel modeling using LS-SVR based on Cultural Differential Evolution with Ant Search is proposed. LS-SVM is adopted to establish the model of the net value of ammonia. The modeling method has fast convergence speed and good global adaptability for identification of the ammonia synthesis process. The LS-SVR model was established using the above-mentioned method. Simulation results verify the validity of the method.

  2. Modeling of alkynes: synthesis and theoretical properties

    Directory of Open Access Journals (Sweden)

    Renato Rosseto

    2003-06-01

    Full Text Available In this paper we present the synthesis and simulation of alkynes derivatives. Semiempirical calculations were carried out for the ground and first excited states, including the spectroscopic properties of the absorption and emission (fluorescence and phosphorescence spectra by INDO/S-CI and DNdM-INDO/S-CI methods with geometries fully optimized by PM3/CI. The fact that the theoretical spectra are in accord with the experimental absorption spectra gives us a new possible approach on how structure modifications could affect the non-linear optical properties of alkynes.

  3. Photonic arbitrary waveform generator based on Taylor synthesis method

    DEFF Research Database (Denmark)

    Liao, Shasha; Ding, Yunhong; Dong, Jianji

    2016-01-01

    Arbitrary waveform generation has been widely used in optical communication, radar system and many other applications. We propose and experimentally demonstrate a silicon-on-insulator (SOI) on chip optical arbitrary waveform generator, which is based on Taylor synthesis method. In our scheme......, a Gaussian pulse is launched to some cascaded microrings to obtain first-, second- and third-order differentiations. By controlling amplitude and phase of the initial pulse and successive differentiations, we can realize an arbitrary waveform generator according to Taylor expansion. We obtain several typical...... waveforms such as square waveform, triangular waveform, flat-top waveform, sawtooth waveform, Gaussian waveform and so on. Unlike other schemes based on Fourier synthesis or frequency-to-time mapping, our scheme is based on Taylor synthesis method. Our scheme does not require any spectral disperser or large...

  4. Model based methods and tools for process systems engineering

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    Process systems engineering (PSE) provides means to solve a wide range of problems in a systematic and efficient manner. This presentation will give a perspective on model based methods and tools needed to solve a wide range of problems in product-process synthesis-design. These methods and tools...... need to be integrated with work-flows and data-flows for specific product-process synthesis-design problems within a computer-aided framework. The framework therefore should be able to manage knowledge-data, models and the associated methods and tools needed by specific synthesis-design work...... of model based methods and tools within a computer aided framework for product-process synthesis-design will be highlighted....

  5. A variational synthesis nodal discrete ordinates method

    International Nuclear Information System (INIS)

    Favorite, J.A.; Stacey, W.M.

    1999-01-01

    A self-consistent nodal approximation method for computing discrete ordinates neutron flux distributions has been developed from a variational functional for neutron transport theory. The advantage of the new nodal method formulation is that it is self-consistent in its definition of the homogenized nodal parameters, the construction of the global nodal equations, and the reconstruction of the detailed flux distribution. The efficacy of the method is demonstrated by two-dimensional test problems

  6. Synthesis, model and stability of helically coiled carbon nanotubes

    DEFF Research Database (Denmark)

    Fejes, Dora; Raffai, Manuella; Hernadi, Klara

    2013-01-01

    Structural model of helically coiled carbon nanotubes is proposed. It is constructed by means of topological coordinate method. Relaxation and cohesive energy calculation are performed by molecular mechanics, using second-generation bond order potential for hydrocarbons introduced by D. W. Brenner....... Our experiments focused on the production and development of catalysts for the synthesis of helically coiled CNTs (carbon nanotubes). The catalysts were tested in the decomposition of acetylene by CCVD (Catalytic Chemical Vapor Deposition) method. The carbon deposit was imaged by TEM (Transmission...

  7. Testing and building theories: mixed methods synthesis

    OpenAIRE

    Harden, Angela

    2008-01-01

    Presentation on use of mixed methods in diverse study types, which combines the findings of ‘qualitative’ and ‘quantitative’ studies within a single systematic review, in order to address the same, overlapping or complementary review questions.

  8. Origins, Methods and Advances in Qualitative Meta-Synthesis

    Science.gov (United States)

    Nye, Elizabeth; Melendez-Torres, G. J.; Bonell, Chris

    2016-01-01

    Qualitative research is a broad term encompassing many methods. Critiques of the field of qualitative research argue that while individual studies provide rich descriptions and insights, the absence of connections drawn between studies limits their usefulness. In response, qualitative meta-synthesis serves as a design to interpret and synthesise…

  9. Data synthesis methods for semantic segmentation in agriculture

    NARCIS (Netherlands)

    Barth, R.; IJsselmuiden, J.; Hemming, J.; Henten, van E.J.

    2018-01-01

    This paper provides synthesis methods for large-scale semantic image segmentation datasets of agricultural scenes with the objective to bridge the gap between state-of-the art computer vision performance and that of computer vision in the agricultural robotics domain. We propose a novel

  10. Method of Pentest Synthesis and Vulnerability Detection

    OpenAIRE

    Hahanova Irina Vitalyevna

    2012-01-01

    The structural method for penetration test generation and vulnerability simulation for infrastructure of telecommunication hardwaresoftware information cybernetic systems (CS), focused to protect against unauthorized access the services defined in the system specification by means of penetrating through legal interfaces of component interaction, which have vulnerabilities, is proposed. A protection service infrastructure is created with cybersystem and maintains it during the life cycle, serv...

  11. Nanosilicon properties, synthesis, applications, methods of analysis and control

    CERN Document Server

    Ischenko, Anatoly A; Aslalnov, Leonid A

    2015-01-01

    Nanosilicon: Properties, Synthesis, Applications, Methods of Analysis and Control examines the latest developments on the physics and chemistry of nanosilicon. The book focuses on methods for producing nanosilicon, its electronic and optical properties, research methods to characterize its spectral and structural properties, and its possible applications. The first part of the book covers the basic properties of semiconductors, including causes of the size dependence of the properties, structural and electronic properties, and physical characteristics of the various forms of silicon. It presents theoretical and experimental research results as well as examples of porous silicon and quantum dots. The second part discusses the synthesis of nanosilicon, modification of the surface of nanoparticles, and properties of the resulting particles. The authors give special attention to the photoluminescence of silicon nanoparticles. The third part describes methods used for studying and controlling the structure and pro...

  12. Method and apparatus for chemical synthesis

    Science.gov (United States)

    Kong; Peter C. , Herring; J. Stephen , Grandy; Jon D.

    2007-12-04

    A method and apparatus for forming a chemical hydride is described and which includes a pseudo-plasma-electrolysis reactor which is operable to receive a solution capable of forming a chemical hydride and which further includes a cathode and a movable anode, and wherein the anode is moved into and out of fluidic, ohmic electrical contact with the solution capable of forming a chemical hydride and which further, when energized produces an oxygen plasma which facilitates the formation of a chemical hydride in the solution.

  13. Modeling consonant-vowel coarticulation for articulatory speech synthesis.

    Directory of Open Access Journals (Sweden)

    Peter Birkholz

    Full Text Available A central challenge for articulatory speech synthesis is the simulation of realistic articulatory movements, which is critical for the generation of highly natural and intelligible speech. This includes modeling coarticulation, i.e., the context-dependent variation of the articulatory and acoustic realization of phonemes, especially of consonants. Here we propose a method to simulate the context-sensitive articulation of consonants in consonant-vowel syllables. To achieve this, the vocal tract target shape of a consonant in the context of a given vowel is derived as the weighted average of three measured and acoustically-optimized reference vocal tract shapes for that consonant in the context of the corner vowels /a/, /i/, and /u/. The weights are determined by mapping the target shape of the given context vowel into the vowel subspace spanned by the corner vowels. The model was applied for the synthesis of consonant-vowel syllables with the consonants /b/, /d/, /g/, /l/, /r/, /m/, /n/ in all combinations with the eight long German vowels. In a perception test, the mean recognition rate for the consonants in the isolated syllables was 82.4%. This demonstrates the potential of the approach for highly intelligible articulatory speech synthesis.

  14. Method for synthesis of high quality graphene

    Science.gov (United States)

    Lanzara, Alessandra [Piedmont, CA; Schmid, Andreas K [Berkeley, CA; Yu, Xiaozhu [Berkeley, CA; Hwang, Choonkyu [Albany, CA; Kohl, Annemarie [Beneditkbeuern, DE; Jozwiak, Chris M [Oakland, CA

    2012-03-27

    A method is described herein for the providing of high quality graphene layers on silicon carbide wafers in a thermal process. With two wafers facing each other in close proximity, in a first vacuum heating stage, while maintained at a vacuum of around 10.sup.-6 Torr, the wafer temperature is raised to about 1500.degree. C., whereby silicon evaporates from the wafer leaving a carbon rich surface, the evaporated silicon trapped in the gap between the wafers, such that the higher vapor pressure of silicon above each of the wafers suppresses further silicon evaporation. As the temperature of the wafers is raised to about 1530.degree. C. or more, the carbon atoms self assemble themselves into graphene.

  15. Learning strategies: a synthesis and conceptual model

    Science.gov (United States)

    Hattie, John A. C.; Donoghue, Gregory M.

    2016-08-01

    The purpose of this article is to explore a model of learning that proposes that various learning strategies are powerful at certain stages in the learning cycle. The model describes three inputs and outcomes (skill, will and thrill), success criteria, three phases of learning (surface, deep and transfer) and an acquiring and consolidation phase within each of the surface and deep phases. A synthesis of 228 meta-analyses led to the identification of the most effective strategies. The results indicate that there is a subset of strategies that are effective, but this effectiveness depends on the phase of the model in which they are implemented. Further, it is best not to run separate sessions on learning strategies but to embed the various strategies within the content of the subject, to be clearer about developing both surface and deep learning, and promoting their associated optimal strategies and to teach the skills of transfer of learning. The article concludes with a discussion of questions raised by the model that need further research.

  16. Boundary flexibility method of component mode synthesis using static Ritz vectors

    Science.gov (United States)

    Abdallah, A. A.; Huckelbridge, A. A.

    1990-01-01

    A method of dynamic substructuring is presented which provides for the incorporation of a set of static Ritz vectors, referred to as boundary flexibility vectors, as a replacement and/or supplement to conventional eigenvectors in component mode synthesis. The suggested boundary flexibility Ritz vectors are generated by an extension of Wilson's load-dependent Ritz vector algorithm for transient dynamic analysis. The extended algorithm is not load-dependent, is applicable to both fixed-and free-interface components, and results in a general component mode synthesis model appropriate for any type of dynamic analysis.

  17. A New Method for Nano Tube Imogolite Synthesis

    Science.gov (United States)

    Abidin, Zaenal; Matsue, Naoto; Henmi, Teruo

    2008-06-01

    A new orthosilicate source from dissolution of poly(silicic acid) for imogolite synthesis has been investigated. We have shown that dialysis membrane method can be used to produce orthosilicic acid from dissolution of poly(silicic acid). The amounts of soluble silica in the solution increases with increasing time and temperature, however always reach constant in the concentration less than 3.6 mM. By diluting the concentration of soluble silica becomes less more 2 mM, this solution was used to imogolite synthesis. The imogolite product has high purity and larger diameter than natural imogolite. We suggest that most of the soluble silica solutions contain silicic acid dominant as monomeric form than low polymeric species during poly(silicic acid) dissolved. This new method seems to be applied to produce imogolite in a large scale by combination between batch and flow system in the industrial field.

  18. Serotonin synthesis, release and reuptake in terminals: a mathematical model

    Directory of Open Access Journals (Sweden)

    Best Janet

    2010-08-01

    Full Text Available Abstract Background Serotonin is a neurotransmitter that has been linked to a wide variety of behaviors including feeding and body-weight regulation, social hierarchies, aggression and suicidality, obsessive compulsive disorder, alcoholism, anxiety, and affective disorders. Full understanding of serotonergic systems in the central nervous system involves genomics, neurochemistry, electrophysiology, and behavior. Though associations have been found between functions at these different levels, in most cases the causal mechanisms are unknown. The scientific issues are daunting but important for human health because of the use of selective serotonin reuptake inhibitors and other pharmacological agents to treat disorders in the serotonergic signaling system. Methods We construct a mathematical model of serotonin synthesis, release, and reuptake in a single serotonergic neuron terminal. The model includes the effects of autoreceptors, the transport of tryptophan into the terminal, and the metabolism of serotonin, as well as the dependence of release on the firing rate. The model is based on real physiology determined experimentally and is compared to experimental data. Results We compare the variations in serotonin and dopamine synthesis due to meals and find that dopamine synthesis is insensitive to the availability of tyrosine but serotonin synthesis is sensitive to the availability of tryptophan. We conduct in silico experiments on the clearance of extracellular serotonin, normally and in the presence of fluoxetine, and compare to experimental data. We study the effects of various polymorphisms in the genes for the serotonin transporter and for tryptophan hydroxylase on synthesis, release, and reuptake. We find that, because of the homeostatic feedback mechanisms of the autoreceptors, the polymorphisms have smaller effects than one expects. We compute the expected steady concentrations of serotonin transporter knockout mice and compare to

  19. Methods for the synthesis of donor-acceptor cyclopropanes

    Science.gov (United States)

    Tomilov, Yu V.; Menchikov, L. G.; Novikov, R. A.; Ivanova, O. A.; Trushkov, I. V.

    2018-03-01

    The interest in cyclopropane derivatives is caused by the facts that, first, the three-carbon ring is present in quite a few natural and biologically active compounds and, second, compounds with this ring are convenient building blocks for the synthesis of diverse molecules (acyclic, alicyclic and heterocyclic). The carbon–carbon bonds in cyclopropane are kinetically rather inert; hence, they need to be activated to be involved in reactions. An efficient way of activation is to introduce vicinal electron-donating and electron-withdrawing substituents into the ring; these substrates are usually referred to as donor-acceptor cyclopropanes. This review gives a systematic account of the key methods for the synthesis of donor-acceptor cyclopropanes. The most important among them are reactions of nucleophilic alkenes with diazo compounds and iodonium ylides and approaches based on reactions of electrophilic alkenes with sulfur ylides (the Corey–Chaykovsky reaction). Among other methods used for this purpose, noteworthy are cycloalkylation of CH-acids, addition of α-halocarbonyl compounds to alkenes, cyclization via 1,3-elimination, reactions of alkenes with halocarbenes followed by reduction, the Simmons–Smith reaction and some other. The scope of applicability and prospects of various methods for the synthesis of donor-acceptor cyclopropanes are discussed. The bibliography includes 530 references.

  20. Realist synthesis: illustrating the method for implementation research

    Directory of Open Access Journals (Sweden)

    Rycroft-Malone Jo

    2012-04-01

    Full Text Available Abstract Background Realist synthesis is an increasingly popular approach to the review and synthesis of evidence, which focuses on understanding the mechanisms by which an intervention works (or not. There are few published examples of realist synthesis. This paper therefore fills a gap by describing, in detail, the process used for a realist review and synthesis to answer the question ‘what interventions and strategies are effective in enabling evidence-informed healthcare?’ The strengths and challenges of conducting realist review are also considered. Methods The realist approach involves identifying underlying causal mechanisms and exploring how they work under what conditions. The stages of this review included: defining the scope of the review (concept mining and framework formulation; searching for and scrutinising the evidence; extracting and synthesising the evidence; and developing the narrative, including hypotheses. Results Based on key terms and concepts related to various interventions to promote evidence-informed healthcare, we developed an outcome-focused theoretical framework. Questions were tailored for each of four theory/intervention areas within the theoretical framework and were used to guide development of a review and data extraction process. The search for literature within our first theory area, change agency, was executed and the screening procedure resulted in inclusion of 52 papers. Using the questions relevant to this theory area, data were extracted by one reviewer and validated by a second reviewer. Synthesis involved organisation of extracted data into evidence tables, theming and formulation of chains of inference, linking between the chains of inference, and hypothesis formulation. The narrative was developed around the hypotheses generated within the change agency theory area. Conclusions Realist synthesis lends itself to the review of complex interventions because it accounts for context as well as

  1. RF building block modeling: optimization and synthesis

    NARCIS (Netherlands)

    Cheng, W.

    2012-01-01

    For circuit designers it is desirable to have relatively simple RF circuit models that do give decent estimation accuracy and provide sufficient understanding of circuits. Chapter 2 in this thesis shows a general weak nonlinearity model that meets these demands. Using a method that is related to

  2. Modeling and synthesis of strong ground motion

    Indian Academy of Sciences (India)

    Numerical examples are shown for illustration by taking Kutch earthquake-2001 as a case study. 1. ... Ground motion; source mechanism models; empirical Green's functions; seismological models; Kutch earthquake. J. Earth Syst. Sci. 117 ..... hybrid global search method which is a combi- nation of simulated annealing and ...

  3. Predictive Mathematical Model for Polyhydroxybutyrate Synthesis in Escherichia coli

    OpenAIRE

    Dixon, Angela

    2011-01-01

    Polyhydroxybutyrate has been studied as a potential biodegradable replacement for petrochemical plastics. Polyhydroxybutyrate synthesis is not native to Escherichia coli, but the genes have successfully been inserted through plasmids. However, polyhydroxybutyrate production needs to be more cost-effective before it can be commercially produced. A mathematical model for polyhydroxybutyrate synthesis was developed to identify genes that could be altered to increase polyhydroxybutyrate productio...

  4. Building block synthesis using the polymerase chain assembly method.

    Science.gov (United States)

    Marchand, Julie A; Peccoud, Jean

    2012-01-01

    De novo gene synthesis allows the creation of custom DNA molecules without the typical constraints of traditional cloning assembly: scars, restriction site incompatibility, and the quest to find all the desired parts to name a few. Moreover, with the help of computer-assisted design, the perfect DNA molecule can be created along with its matching sequence ready to download. The challenge is to build the physical DNA molecules that have been designed with the software. Although there are several DNA assembly methods, this section presents and describes a method using the polymerase chain assembly (PCA).

  5. Explorative methods in linear models

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar

    2004-01-01

    The author has developed the H-method of mathematical modeling that builds up the model by parts, where each part is optimized with respect to prediction. Besides providing with better predictions than traditional methods, these methods provide with graphic procedures for analyzing different feat...... features in data. These graphic methods extend the well-known methods and results of Principal Component Analysis to any linear model. Here the graphic procedures are applied to linear regression and Ridge Regression....

  6. Model-Based Synthesis of Visual Speech Movements from 3D Video

    Directory of Open Access Journals (Sweden)

    Edge JamesD

    2009-01-01

    Full Text Available We describe a method for the synthesis of visual speech movements using a hybrid unit selection/model-based approach. Speech lip movements are captured using a 3D stereo face capture system and split up into phonetic units. A dynamic parameterisation of this data is constructed which maintains the relationship between lip shapes and velocities; within this parameterisation a model of how lips move is built and is used in the animation of visual speech movements from speech audio input. The mapping from audio parameters to lip movements is disambiguated by selecting only the most similar stored phonetic units to the target utterance during synthesis. By combining properties of model-based synthesis (e.g., HMMs, neural nets with unit selection we improve the quality of our speech synthesis.

  7. Synthesis and characterization of cobalt sulfide nanoparticles by sonochemical method

    Science.gov (United States)

    Muradov, Mustafa B.; Balayeva, Ofeliya O.; Azizov, Abdulsaid A.; Maharramov, Abel M.; Qahramanli, Lala R.; Eyvazova, Goncha M.; Aghamaliyev, Zohrab A.

    2018-03-01

    Convenient and environmentally friendly synthesis of Co9S8/PVA, CoxSy/EG and CoxSy/3-MPA nanocomposites were carried out in the presence of ultrasonic irradiation by the liquid phase synthesis of the sonochemical method. For the synthesis, cobalt acetate tetrahydrate [Co(CH3COO)2·4H2O] and sodium sulfide (Na2S·9H2O) were used as a cobalt and sulfur precursor, respectively. Polyvinyl alcohol (PVA), ethylene glycol (EG) and 3-mercaptopropionic acid (3-MPA) were used as a capping agent and surfactant. The structural, optical properties and morphology of nanocomposites were characterized using X-ray diffractometer (XRD), Ultraviolet/Visible Spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The optical band gap of Co9S8/PVA is 1.81 eV and for CoxSy/EG is 2.42 eV, where the direct band gap of bulk cobalt sulfide is (0.78-0.9 eV). The wide band gap indicates that synthesised nanocomposites can be used in the fabrication of optical and photonic devices. The growth mechanisms of the Co9S8, CoS2 and Co3S4 nanoparticles were discussed by the reactions. The effects of sonication time and annealing temperature on the properties of the nanoparticles have been studied in detail.

  8. Modeling and computer simulation of ion beam synthesis of nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, M.

    1999-11-01

    The following topics were dealt with: ion beam synthesis of nanoclusters, kinetic three dimensional lattice Monte Carlo method, Ostwald ripening, redistribution of implanted impurities, buried layer formation, comparisation to experimental results.

  9. Kinetic model of ammonia synthesis in the solar nebula

    Science.gov (United States)

    Norris, T. L.

    1980-03-01

    Kinetic model of ammonia formation by iron catalysis in the primordial solar nebula is developed. The maximum time to reach equilibrium concentration is determined for various temperatures between 1000 and 200 K on the basis of reaction rates derived from industrial data on iron catalysts for ammonia. Application of the method for calculating the equilibrium time to an arbitrary nebula cooling model which maximizes the time available for ammonia synthesis results in an upper limit of 3% of the equilibrium value to the proportion of nitrogen in the form of ammonia at the time of planetary accretion, with ammonia abundance decreasing with distance from the sun. It is concluded that kinetic rather than equilibrium considerations control the abundance of ammonia in the solar nebula, and implications of the dominance of nitrogen for the evolution of the atmospheres of the terrestrial and Jovian planets and the composition of comets are indicated.

  10. Methods for the synthesis of α,β-unsaturated trifluoromethyl ketones and their use in organic synthesis

    International Nuclear Information System (INIS)

    Nenajdenko, Valentine G; Sanin, Andrei V; Balenkova, Elizabeth S

    1999-01-01

    Published data on the methods of synthesis and properties of α,β-unsaturated trifluoromethyl-containing ketones are surveyed and described systematically. Primary attention is devoted to the use of these compounds in organic synthesis as useful building blocks for the preparation of various compounds bearing a trifluoromethyl group. The bibliography includes 133 references.

  11. Comparative Studies of Population Synthesis Models in the ...

    Indian Academy of Sciences (India)

    Comparative Studies of Population Synthesis Models in the Framework of Modified Strömgren Filters ... The study conveys a good agreement of GALEV models with modified Strömgren colours but with poor UV model predictions and observed globular cluster data, while the spectroscopic models perform badly because of ...

  12. SYNTHESIS OF ALUMINIUM BORATE WHISKERS THROUGH WET MOLTEN SALT METHOD

    Directory of Open Access Journals (Sweden)

    Xue Zhang

    2017-12-01

    Full Text Available Aluminium borate (Al₄B₂O₉ whiskers were successfully synthesized by the wet molten salt method at 800 oC through control the aluminum/boron atomic ratio and synthesis temperature. The as-received Al₄B₂O₉ whiskers were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD and thermal analysis. A solution-liquid-solid (SLS mechanism was proposed for the growth mechanism of the whiskers on the basis of the experimental phenomena and the TG-DSC data of the mixed raw materials.

  13. Formal and heuristic system decomposition methods in multidisciplinary synthesis

    Science.gov (United States)

    Bloebaum, Christina Lynne

    The multidisciplinary interactions which exist in large scale engineering design problems provide a unique set of difficulties. These difficulties are associated primarily with unwieldy numbers of design variables and constraints, and with the interdependencies of the discipline analysis modules. Such obstacles require design techniques which account for the inherent disciplinary couplings in the analyses and optimizations. The objective of this work is to develop an efficient holistic design synthesis methodology that takes advantage of the synergistic nature of integrated design. Although the design process encompasses several stages in which optimization methods could be applied, the present study addresses the applications of optimization in the preliminary design stage, in which the most capability for positive change exists. A primary concern in this stage involves implementation of an accurate and efficient mathematical representation of large engineering systems. Without such a representation, meaningful design synthesis is impossible. Multilevel decomposition methods provide a systematic approach for decoupling the large complex systems found in multidisciplinary design problems into smaller, more manageable subsystems. These methods account for the couplings between the intrinsically linked disciplinary analysis modules on the basis of a linear sensitivity analysis. In a majority of such efforts, the decomposition is governed either by an obvious hierarchy in the system or on the basis of discipline.

  14. Developing the Business Modelling Method

    NARCIS (Netherlands)

    Meertens, Lucas Onno; Iacob, Maria Eugenia; Nieuwenhuis, Lambertus Johannes Maria; Shishkov, B; Shishkov, Boris

    2011-01-01

    Currently, business modelling is an art, instead of a science, as no scientific method for business modelling exists. This, and the lack of using business models altogether, causes many projects to end after the pilot stage, unable to fulfil their apparent promise. We propose a structured method to

  15. Parameter Estimation of a Plucked String Synthesis Model Using a Genetic Algorithm with Perceptual Fitness Calculation

    Directory of Open Access Journals (Sweden)

    Riionheimo Janne

    2003-01-01

    Full Text Available We describe a technique for estimating control parameters for a plucked string synthesis model using a genetic algorithm. The model has been intensively used for sound synthesis of various string instruments but the fine tuning of the parameters has been carried out with a semiautomatic method that requires some hand adjustment with human listening. An automated method for extracting the parameters from recorded tones is described in this paper. The calculation of the fitness function utilizes knowledge of the properties of human hearing.

  16. An exploratory study on the driving method of speech synthesis based on the human eye reading imaging data

    Science.gov (United States)

    Gao, Pei-pei; Liu, Feng

    2016-10-01

    With the development of information technology and artificial intelligence, speech synthesis plays a significant role in the fields of Human-Computer Interaction Techniques. However, the main problem of current speech synthesis techniques is lacking of naturalness and expressiveness so that it is not yet close to the standard of natural language. Another problem is that the human-computer interaction based on the speech synthesis is too monotonous to realize mechanism of user subjective drive. This thesis introduces the historical development of speech synthesis and summarizes the general process of this technique. It is pointed out that prosody generation module is an important part in the process of speech synthesis. On the basis of further research, using eye activity rules when reading to control and drive prosody generation was introduced as a new human-computer interaction method to enrich the synthetic form. In this article, the present situation of speech synthesis technology is reviewed in detail. Based on the premise of eye gaze data extraction, using eye movement signal in real-time driving, a speech synthesis method which can express the real speech rhythm of the speaker is proposed. That is, when reader is watching corpora with its eyes in silent reading, capture the reading information such as the eye gaze duration per prosodic unit, and establish a hierarchical prosodic pattern of duration model to determine the duration parameters of synthesized speech. At last, after the analysis, the feasibility of the above method is verified.

  17. A direct method for the synthesis of orthogonally protected furyl- and thienyl- amino acids.

    Science.gov (United States)

    Hudson, Alex S; Caron, Laurent; Colgin, Neil; Cobb, Steven L

    2015-04-01

    The synthesis of unnatural amino acids plays a key part in expanding the potential application of peptide-based drugs and in the total synthesis of peptide natural products. Herein, we report a direct method for the synthesis of orthogonally protected 5-membered heteroaromatic amino acids.

  18. Optimum strategies for nuclear energy system development (method of synthesis)

    International Nuclear Information System (INIS)

    Belenky, V.Z.

    1983-01-01

    The problem of optimum long-term development of the nuclear energy system is considered. The optimum strategies (i.e. minimum total uranium consumption) for the transition phase leading to a stationary regime of development are found. For this purpose the author has elaborated a new method of solving linear problems of optimal control which can include jumps in trajectories. The method gives a possibility to fulfil a total synthesis of optimum strategies. A key characteristic of the problem is the productivity function of the nuclear energy system which connects technological system parameters with its growth rate. There are only two types of optimum strategies, according to an increasing or decreasing productivity function. Both cases are illustrated with numerical examples. (orig.) [de

  19. Methods of statistical model estimation

    CERN Document Server

    Hilbe, Joseph

    2013-01-01

    Methods of Statistical Model Estimation examines the most important and popular methods used to estimate parameters for statistical models and provide informative model summary statistics. Designed for R users, the book is also ideal for anyone wanting to better understand the algorithms used for statistical model fitting. The text presents algorithms for the estimation of a variety of regression procedures using maximum likelihood estimation, iteratively reweighted least squares regression, the EM algorithm, and MCMC sampling. Fully developed, working R code is constructed for each method. Th

  20. Synthesis method for using in the design of an electron gun for gyrotion

    International Nuclear Information System (INIS)

    Silva, C.A.B.

    1987-09-01

    In this work a synthesis method is applied to the design of an electron gun for a 94GHz gyrotron. Using the synthesis method, it is found the shape of the electrodes compatible with the laminar flow which minimizes the action of space change on the electron velocity dispersion. A sistematic procedure is presented to fuid the parameters of the synthesis method which, in turn, are closely related to the characteristics of the aptoclechonic system. (author) [pt

  1. Depth no-synthesis-error model for view synthesis in 3-D video.

    Science.gov (United States)

    Zhao, Yin; Zhu, Ce; Chen, Zhenzhong; Yu, Lu

    2011-08-01

    Currently, 3-D Video targets at the application of disparity-adjustable stereoscopic video, where view synthesis based on depth-image-based rendering (DIBR) is employed to generate virtual views. Distortions in depth information may introduce geometry changes or occlusion variations in the synthesized views. In practice, depth information is stored in 8-bit grayscale format, whereas the disparity range for a visually comfortable stereo pair is usually much less than 256 levels. Thus, several depth levels may correspond to the same integer (or sub-pixel) disparity value in the DIBR-based view synthesis such that some depth distortions may not result in geometry changes in the synthesized view. From this observation, we develop a depth no-synthesis-error (D-NOSE) model to examine the allowable depth distortions in rendering a virtual view without introducing any geometry changes. We further show that the depth distortions prescribed by the proposed D-NOSE profile also do not compromise the occlusion order in view synthesis. Therefore, a virtual view can be synthesized losslessly if depth distortions follow the D-NOSE specified thresholds. Our simulations validate the proposed D-NOSE model in lossless view synthesis and demonstrate the gain with the model in depth coding.

  2. Analysis and synthesis for interval type-2 fuzzy-model-based systems

    CERN Document Server

    Li, Hongyi; Lam, Hak-Keung; Gao, Yabin

    2016-01-01

    This book develops a set of reference methods capable of modeling uncertainties existing in membership functions, and analyzing and synthesizing the interval type-2 fuzzy systems with desired performances. It also provides numerous simulation results for various examples, which fill certain gaps in this area of research and may serve as benchmark solutions for the readers. Interval type-2 T-S fuzzy models provide a convenient and flexible method for analysis and synthesis of complex nonlinear systems with uncertainties.

  3. Controlled Synthesis of ZnO Nanostructures by Electrodeposition Method

    Directory of Open Access Journals (Sweden)

    Gong Jiangfeng

    2010-01-01

    Full Text Available We present here a systematic study on the synthesis of various ZnO nanostructures by electrodeposition method with ZnCl2 solution as starting reactant. Several reaction parameters were examined to develop an optimal procedure for controlling the size, shape, and surface morphology of the nanostructure. The results showed that the morphology of the products can be carefully controlled through adjusting the concentration of the electrolyte. The products present well-aligned nanorod arrays when the concentration is low. However, they act as anomalous hexangular nanoplates when the concentration of ZnCl2 is higher than 5 mM. Transmission electron microscopy and select area electron diffraction results show that the product presents good crystallinity. A possible formation process has been proposed.

  4. Porous metal oxide particles and their methods of synthesis

    Science.gov (United States)

    Chen, Fanglin; Liu, Qiang

    2013-03-12

    Methods are generally disclosed for synthesis of porous particles from a solution formed from a leaving agent, a surfactant, and a soluble metal salt in a solvent. The surfactant congregates to form a nanoparticle core such that the metal salt forms about the nanoparticle core to form a plurality of nanoparticles. The solution is heated such that the leaving agent forms gas bubbles in the solution, and the plurality of nanoparticles congregate about the gas bubbles to form a porous particle. The porous particles are also generally disclosed and can include a particle shell formed about a core to define an average diameter from about 0.5 .mu.m to about 50 .mu.m. The particle shell can be formed from a plurality of nanoparticles having an average diameter of from about 1 nm to about 50 nm and defined by a metal salt formed about a surfactant core.

  5. Aperture Synthesis Methods and Applications to Optical Astronomy

    CERN Document Server

    Saha, Swapan Kumar

    2011-01-01

    Over the years long baseline optical interferometry has slowly gained in importance and today it is a powerful tool. This timely book sets out to highlight the basic principles of long baseline optical interferometry. The book addresses the fundamentals of stellar interferometry with emphasis on aperture synthesis using an array of telescopes particularly at optical/IR wavelengths. It discusses the fundamentals of electromagnetic fields, wave optics, interference, diffraction, and imaging at length. There is a chapter dedicated to radio and intensity interferometry corroborating with basic mathematical steps. The basic principle of optical interferometry and its requirements, its limitations and the technical challenges it poses, are also covered in depth. Assisted by illustrations and footnotes, the book examines the basic tricks of the trade, current trends and methods, and it points to the potential of true interferometry both from the ground and space.

  6. Implementation of the block-Krylov boundary flexibility method of component synthesis

    Science.gov (United States)

    Carney, Kelly S.; Abdallah, Ayman A.; Hucklebridge, Arthur A.

    1993-05-01

    A method of dynamic substructuring is presented which utilizes a set of static Ritz vectors as a replacement for normal eigenvectors in component mode synthesis. This set of Ritz vectors is generated in a recurrence relationship, which has the form of a block-Krylov subspace. The initial seed to the recurrence algorithm is based on the boundary flexibility vectors of the component. This algorithm is not load-dependent, is applicable to both fixed and free-interface boundary components, and results in a general component model appropriate for any type of dynamic analysis. This methodology was implemented in the MSC/NASTRAN normal modes solution sequence using DMAP. The accuracy is found to be comparable to that of component synthesis based upon normal modes. The block-Krylov recurrence algorithm is a series of static solutions and so requires significantly less computation than solving the normal eigenspace problem.

  7. Graph modeling systems and methods

    Science.gov (United States)

    Neergaard, Mike

    2015-10-13

    An apparatus and a method for vulnerability and reliability modeling are provided. The method generally includes constructing a graph model of a physical network using a computer, the graph model including a plurality of terminating vertices to represent nodes in the physical network, a plurality of edges to represent transmission paths in the physical network, and a non-terminating vertex to represent a non-nodal vulnerability along a transmission path in the physical network. The method additionally includes evaluating the vulnerability and reliability of the physical network using the constructed graph model, wherein the vulnerability and reliability evaluation includes a determination of whether each terminating and non-terminating vertex represents a critical point of failure. The method can be utilized to evaluate wide variety of networks, including power grid infrastructures, communication network topologies, and fluid distribution systems.

  8. Facile synthesis of labile gold nanodiscs by the Turkevich method

    Science.gov (United States)

    Grasseschi, Daniel; de O. Pereira, Maria Luiza; Shinohara, Jorge S.; Toma, Henrique E.

    2018-02-01

    The Turkevich method has been the preferred one for synthesis of gold nanoparticles (AuNPs), owing to its apparent simplicity and facility of replacing the citrate ions on the particle surface by molecules exhibiting different functionalities. Using the most common procedure labile spherical nanoparticles are usually obtained by this method. Here, by using factorial design of experiments, we demonstrated that gold nanodiscs (AuNDs) with short aspect ratio can be generated by the Turkevich method when Au:citrate ratio is 1:1. In comparison with the CTAB capped gold nanorods (AuNR), the citrate stabilized AuNDs exhibited a more labile character, allowing fast ligand exchange reactions and easy functionalization of the nanoparticle surface. In the presence of 4-mercaptopyridine (4-mpy), the surface enhancement Raman scattering effect was 100 and 1000 times higher than the one observed for CTAB-AuNR and spherical AuNPs, respectively, increasing the 4-mpy detection limit to 2.5 × 10-9 molL-1.

  9. Ultrasound assisted synthesis of nanocrystalline zinc oxide: Experiments and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Hosni, Mongia [Laboratoire des Sciences des Procédés et des Matériaux, LSPM-CNRS, Université Paris 13, 99 av. J.B. Clément, 93430 Villetaneuse (France); Farhat, Samir, E-mail: farhat@lspm.cnrs.fr [Laboratoire des Sciences des Procédés et des Matériaux, LSPM-CNRS, Université Paris 13, 99 av. J.B. Clément, 93430 Villetaneuse (France); Schoenstein, Frederic; Karmous, Farah; Jouini, Noureddine [Laboratoire des Sciences des Procédés et des Matériaux, LSPM-CNRS, Université Paris 13, 99 av. J.B. Clément, 93430 Villetaneuse (France); Viana, Bruno [LCMCP Chimie-Paristech, UPMC, Collège de France, 11 Rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Mgaidi, Arbi [Laboratoire de chimie minérale industrielle université Tunis el Manar (Tunisia)

    2014-12-05

    Highlights: • ZnO nanospheres and nanowires were grown using ultrasound and thermal activation techniques. • The growth uses forced hydrolysis of zinc acetate in diethylene glycol (DEG). • A thermochemical model was developed based on thermodynamic equilibrium calculations. • We estimate species distribution in the bubble in temperature range from 5000 K to ambient. • We propose a new mechanism for ZnO growth assisted by ultrasound irradiation. - Abstract: A fast and green approach is proposed for the preparation of nanocrystalline zinc oxide (ZnO) via ultrasonic (US) irradiation in polyol medium. The process uses forced hydrolysis of zinc acetate in diethylene glycol (DEG). The protocol is compared to thermal activation under the same chemical environment. The activation method is found to be playing a critical role in the selective synthesis of morphologically distinct nanostructures. As compared to thermally activated conventional polyol process, (US) permits to considerably reduce reaction time as well as size of particles. In addition, the shape of these nanoparticles was changed from long nanowires to small nanospheres, indicating different reaction mechanisms. To explain this difference, a thermochemical model was developed based on thermodynamic equilibrium calculations. The model estimate species distribution in the bubble in temperature range from 5000 K to ambient simulating quenching process during bubble formation and collapse. Our results indicate the presence of high density of zinc atoms that could be responsible of a high density of nucleation as compared to thermal activation.

  10. Ultrasound assisted synthesis of nanocrystalline zinc oxide: Experiments and modelling

    International Nuclear Information System (INIS)

    Hosni, Mongia; Farhat, Samir; Schoenstein, Frederic; Karmous, Farah; Jouini, Noureddine; Viana, Bruno; Mgaidi, Arbi

    2014-01-01

    Highlights: • ZnO nanospheres and nanowires were grown using ultrasound and thermal activation techniques. • The growth uses forced hydrolysis of zinc acetate in diethylene glycol (DEG). • A thermochemical model was developed based on thermodynamic equilibrium calculations. • We estimate species distribution in the bubble in temperature range from 5000 K to ambient. • We propose a new mechanism for ZnO growth assisted by ultrasound irradiation. - Abstract: A fast and green approach is proposed for the preparation of nanocrystalline zinc oxide (ZnO) via ultrasonic (US) irradiation in polyol medium. The process uses forced hydrolysis of zinc acetate in diethylene glycol (DEG). The protocol is compared to thermal activation under the same chemical environment. The activation method is found to be playing a critical role in the selective synthesis of morphologically distinct nanostructures. As compared to thermally activated conventional polyol process, (US) permits to considerably reduce reaction time as well as size of particles. In addition, the shape of these nanoparticles was changed from long nanowires to small nanospheres, indicating different reaction mechanisms. To explain this difference, a thermochemical model was developed based on thermodynamic equilibrium calculations. The model estimate species distribution in the bubble in temperature range from 5000 K to ambient simulating quenching process during bubble formation and collapse. Our results indicate the presence of high density of zinc atoms that could be responsible of a high density of nucleation as compared to thermal activation

  11. A fixed free interface component mode synthesis method for rotordynamic analysis

    Science.gov (United States)

    Shanmugam, A.; Padmanabhan, Chandramouli

    2006-11-01

    A fixed-free interface component mode synthesis method has been developed for carrying out rotordynamic analysis with the gyroscopic effects being considered. This hybrid model has been developed to combine the advantages of the fixed interface method, known popularly as the Craig-Bampton approach and the free interface method, known as the Craig-Chang technique. It is shown in the paper that the proposed fixed-free interface method is able to predict the whirl frequencies accurately (like the Craig-Bampton method) and at the same time predict the unbalance response accurately (like the Craig-Chang approach). The proposed technique has been validated for two systems. (a) a cantilever rotor with a heavy disc at its free end and (b) a typical twin-spool aero-engine rotor-bearing configuration. This technique is also suitable for nonlinear analysis, when a squeeze film damper is present.

  12. Coupling Neumann development and component mode synthesis methods for stochastic analysis of random structures

    Directory of Open Access Journals (Sweden)

    Driss Sarsri

    2014-05-01

    Full Text Available In this paper, we propose a method to calculate the first two moments (mean and variance of the structural dynamics response of a structure with uncertain variables and subjected to random excitation. For this, Newmark method is used to transform the equation of motion of the structure into a quasistatic equilibrium equation in the time domain. The Neumann development method was coupled with Monte Carlo simulations to calculate the statistical values of the random response. The use of modal synthesis methods can reduce the dimensions of the model before integration of the equation of motion. Numerical applications have been developed to highlight effectiveness of the method developed to analyze the stochastic response of large structures.

  13. Tuning of PID controllers for integrating systems using direct synthesis method.

    Science.gov (United States)

    Anil, Ch; Padma Sree, R

    2015-07-01

    A PID controller is designed for various forms of integrating systems with time delay using direct synthesis method. The method is based on comparing the characteristic equation of the integrating system and PID controller with a filter with the desired characteristic equation. The desired characteristic equation comprises of multiple poles which are placed at the same desired location. The tuning parameter is adjusted so as to achieve the desired robustness. Tuning rules in terms of process parameters are given for various forms of integrating systems. The tuning parameter can be selected for the desired robustness by specifying Ms value. The proposed controller design method is applied to various transfer function models and to the nonlinear model equations of jacketed CSTR to show its effectiveness and applicability. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  14. 147 ONE POT METHOD FOR THE SYNTHESIS OF ARYLIDENE ...

    African Journals Online (AJOL)

    The reactivity of condensing aldehyde is an important factor in the synthesis. Presence of alcohol enhances the formation of products. This fact have been utilized for alkali catalyzed synthesis of many arylidene flavanones been reported by them. The special feature of long conjugation with 4-keto group of flavanone moiety.

  15. Homeostatic mechanisms in dopamine synthesis and release: a mathematical model

    Directory of Open Access Journals (Sweden)

    Nijhout H Frederik

    2009-09-01

    Full Text Available Abstract Background Dopamine is a catecholamine that is used as a neurotransmitter both in the periphery and in the central nervous system. Dysfunction in various dopaminergic systems is known to be associated with various disorders, including schizophrenia, Parkinson's disease, and Tourette's syndrome. Furthermore, microdialysis studies have shown that addictive drugs increase extracellular dopamine and brain imaging has shown a correlation between euphoria and psycho-stimulant-induced increases in extracellular dopamine 1. These consequences of dopamine dysfunction indicate the importance of maintaining dopamine functionality through homeostatic mechanisms that have been attributed to the delicate balance between synthesis, storage, release, metabolism, and reuptake. Methods We construct a mathematical model of dopamine synthesis, release, and reuptake and use it to study homeostasis in single dopaminergic neuron terminals. We investigate the substrate inhibition of tyrosine hydroxylase by tyrosine, the consequences of the rapid uptake of extracellular dopamine by the dopamine transporters, and the effects of the autoreceoptors on dopaminergic function. The main focus is to understand the regulation and control of synthesis and release and to explicate and interpret experimental findings. Results We show that the substrate inhibition of tyrosine hydroxylase by tyrosine stabilizes cytosolic and vesicular dopamine against changes in tyrosine availability due to meals. We find that the autoreceptors dampen the fluctuations in extracellular dopamine caused by changes in tyrosine hydroxylase expression and changes in the rate of firing. We show that short bursts of action potentials create significant dopamine signals against the background of tonic firing. We explain the observed time courses of extracellular dopamine responses to stimulation in wild type mice and mice that have genetically altered dopamine transporter densities and the observed

  16. Mathematical model of Fischer-Tropsch catalyst pellet with pointed centers of synthesis

    Science.gov (United States)

    Derevich, I. V.; Fokina, A. Yu

    2017-11-01

    The productivity of Fischer-Tropsch reactors is determined by the efficiency of heat and mass transfer processes inside the catalyst pellets. To reduce the diffusion resistance, the pellet base is made porous. The porous structure of the granules causes a discrete arrangement of cobalt metallic microparticles whose size can reach tens of microns. The distance between these active centres significantly exceeds their characteristic size and the homogeneous catalyst model is incorrect. A mathematical model of heat and mass transfer processes inside a porous spherical pellet with localised active centres is proposed. The heat of the exothermic synthesis reaction is removed from the surface of the granule to the synthesis gas stream washing the catalyst pellet by heat transfer. The components of the synthesis gas enter the granule surface as a result of mass transfer. On the basis of the self-consistent field method, the values of the temperature and concentration of the synthesis gas components at the active centres were determined. It is shown that there is a critical temperature of the synthesis gas washing the granule, exceeding critical temperature leads to a substantial overheating of the active centres. In this case, the surface of the catalyst pellet is superheated slightly. The principal difference between the homogeneous and heterogeneous models in catalytic reactions is discussed.

  17. Synthesis, evaluation and molecular modelling studies of some ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 122; Issue 2. Synthesis, evaluation and molecular modelling studies of some novel 3-(3 ... The compounds have been characterized on the basis of elemental analysis and spectral data. All the compounds were evaluated for their HIV-1 RT inhibitory activity. Among ...

  18. The Advanced Aluminum Nitride Synthesis Methods and Its Applications: Patent Review.

    Science.gov (United States)

    Shishkin, Roman A; Elagin, Andrey A; Mayorova, Ekaterina S; Beketov, Askold R

    2016-01-01

    High purity nanosized aluminum nitride synthesis is a current issue for both industry and science. However, there is no up-to-date review considering the major issues and the technical solutions for different methods. This review aims to investigate the advanced methods of aluminum nitride synthesis and its development tendencies. Also the aluminum nitride application patents and prospects for development of the branch have been considered. The patent search on "aluminum nitride synthesis" has been carried out. The research activity has been analyzed. Special attention has been paid to the patenting geography and the leading researchers in aluminum nitride synthesis. Aluminum nitride synthesis methods have been divided into 6 main groups, the most studied approaches are carbothermal reduction (88 patents) and direct nitridation (107 patents). The current issues for each group have been analyzed; the main trends are purification of the final product and nanopowder synthesis. The leading researchers in aluminum nitride synthesis have represented 5 countries, namely: Japan, China, Russia, South Korea and USA. The main aluminum nitride application spheres are electronics (59,1 percent of applications) and new materials manufacturing (30,9 percent). The review deals with the state of the art data in nanosized aluminum nitride synthesis, the major issues and the technical solutions for different synthesis methods. It gives a full understanding of the development tendencies and of the current leaders in the sphere.

  19. Synthesis and photooxidation of furylthymines; chemiexcitation model studies

    NARCIS (Netherlands)

    Dannenberg, W.; Feringa, Bernard

    1984-01-01

    A method for the synthesis of 1-(5-methyl-2-furoyl)thymine (7) and 1-(5-methyl-2-furyl)thymine (8) is described. Trimethylsilyliodide catalysed addition of 5-methyl-2,4-bis(trimethylsilyloxy)pyrimidine (9) to 2-methyl-2,5-dihydro-2,5-dimethoxyfuran yielded the new thymine derivative 13.

  20. Variational methods in molecular modeling

    CERN Document Server

    2017-01-01

    This book presents tutorial overviews for many applications of variational methods to molecular modeling. Topics discussed include the Gibbs-Bogoliubov-Feynman variational principle, square-gradient models, classical density functional theories, self-consistent-field theories, phase-field methods, Ginzburg-Landau and Helfrich-type phenomenological models, dynamical density functional theory, and variational Monte Carlo methods. Illustrative examples are given to facilitate understanding of the basic concepts and quantitative prediction of the properties and rich behavior of diverse many-body systems ranging from inhomogeneous fluids, electrolytes and ionic liquids in micropores, colloidal dispersions, liquid crystals, polymer blends, lipid membranes, microemulsions, magnetic materials and high-temperature superconductors. All chapters are written by leading experts in the field and illustrated with tutorial examples for their practical applications to specific subjects. With emphasis placed on physical unders...

  1. Application of methods of discrete mathematics at modular synthesis of mechatronic devices

    OpenAIRE

    Nikiforov, S.; Nikiforov, B.; Mandarov, E.; Rabdanova, N.

    2010-01-01

    The article is devoted to application of methods of discrete mathematics (the theory of counts, the method of matrix code and others) and synthesis of executive mechanisms of mechatronic handling devices

  2. Psoralen plus near-ultraviolet light: a possible new method for measuring DNA repair synthesis

    International Nuclear Information System (INIS)

    Heimer, Y.M.; Kol, R.; Shiloh, Y.; Riklis, E.

    1983-01-01

    A new method is proposed to inhibit semiconservative DNA synthesis in cultured cells while DNA repair synthesis is being measured. The cells are treated with the DNA-crosslinking agent Trioxalen (4,5,8-trimethylpsoralen) plus near-ultraviolet light, and consequently 99.5% inhibition of replicative DNA synthesis is achieved. Additional DNA-damaging agents induce thymidine incorporation into the double-stranded regions of the DNA. The new method gave results very similar to those obtained with the benzoylated naphthoylated DEAE (BND) cellulose method using three human fibroblast strains, of which one had deficient capacity for DNA repair synthesis following treatment with gamma rays and methyl methanesulfonate. The advantages of the new method are simplicity and rapidity, as well as the high extent to which replicative DNA synthesis is inhibited

  3. Psoralen plus near-ultraviolet light: a possible new method for measuring DNA repair synthesis

    International Nuclear Information System (INIS)

    Heimer, Y.M.; Kol, R.; Shiloh, Y.; Riklis, E.

    1983-01-01

    A new method is proposed to inhibit semiconservative DNA synthesis in cultured cells while DNA repair synthesis is being measured. The cells are treated with the DNA-crosslinking agent Trioxalen (4,5,8-trimethylpsoralen) plus near-ultraviolet light, and consequently 99.5% inhibition of replicative DNA synthesis is achieved. Additional DNA-damaging agents induce thymidine incorporation into the double-stranded regions of the DNA. The new method gave results very similar to those obtained with the benzoylated naphthoylated DEAE (BND) cellulose method using three human fibroblast strains, of which one had deficient capacity for DNA repair synthesis following treatment with γ rays and methyl methanesulfonate. The advantages of the new method are simplicity and rapidity, as well as the high extent to which replicative DNA synthesis is inhibited

  4. Psoralen plus near-ultraviolet light: a possible new method for measuring DNA repair synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Heimer, Y.M. (Nuclear Research Center, Negev, Israel); Kol, R.; Shiloh, Y.; Riklis, E.

    1983-09-01

    A new method is proposed to inhibit semiconservative DNA synthesis in cultured cells while DNA repair synthesis is being measured. The cells are treated with the DNA-crosslinking agent Trioxalen (4,5,8-trimethylpsoralen) plus near-ultraviolet light, and consequently 99.5% inhibition of replicative DNA synthesis is achieved. Additional DNA-damaging agents induce thymidine incorporation into the double-stranded regions of the DNA. The new method gave results very similar to those obtained with the benzoylated naphthoylated DEAE (BND) cellulose method using three human fibroblast strains, of which one had deficient capacity for DNA repair synthesis following treatment with ..gamma.. rays and methyl methanesulfonate. The advantages of the new method are simplicity and rapidity, as well as the high extent to which replicative DNA synthesis is inhibited.

  5. Multi-line split DNA synthesis: a novel combinatorial method to make high quality peptide libraries

    Directory of Open Access Journals (Sweden)

    Ueno Shingo

    2004-09-01

    Full Text Available Abstract Background We developed a method to make a various high quality random peptide libraries for evolutionary protein engineering based on a combinatorial DNA synthesis. Results A split synthesis in codon units was performed with mixtures of bases optimally designed by using a Genetic Algorithm program. It required only standard DNA synthetic reagents and standard DNA synthesizers in three lines. This multi-line split DNA synthesis (MLSDS is simply realized by adding a mix-and-split process to normal DNA synthesis protocol. Superiority of MLSDS method over other methods was shown. We demonstrated the synthesis of oligonucleotide libraries with 1016 diversity, and the construction of a library with random sequence coding 120 amino acids containing few stop codons. Conclusions Owing to the flexibility of the MLSDS method, it will be able to design various "rational" libraries by using bioinformatics databases.

  6. Synthesis of barium titanate crystalline nanoparticles using hydrothermal microwave method

    International Nuclear Information System (INIS)

    Souza, A.E.; Silva, R.A.; Teixeira, S.R.; Moreira, M.L.; Volanti, D.P.; Longo, E.

    2009-01-01

    The hydrothermal microwave method (HTMW) was used in the synthesis of barium titanate (BaTiO 3 ) nanoparticles. The solution was prepared in deionized water by using titanium (IV) isopropoxide (C 12 H 28 O 4 Ti), barium chloride (BaCl 2 .2H 2 O) and potassium hydroxide (KOH). Afterwards it was heated in an adapted conventional microwave oven. The system is composed of a temperature controller with thermocouple, a hermetic camera of reaction made of teflon, a manometer and a safety valve. The solution was heated to 140 deg C, at a 140 deg C/min heating rate, and maintained at this temperature for 40 minutes. The obtained ceramic powder was characterized by using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The XRD data confirms the formation of a high crystalline ceramic material with perovskite structure. The FE-SEM images reveal morphologies with dimensions varying from 27 to 54 nm. (author)

  7. Synthesis of 3D Model of a Magnetic Field-Influenced Body from a Single Image

    Science.gov (United States)

    Wang, Cuilan; Newman, Timothy; Gallagher, Dennis

    2006-01-01

    A method for recovery of a 3D model of a cloud-like structure that is in motion and deforming but approximately governed by magnetic field properties is described. The method allows recovery of the model from a single intensity image in which the structure's silhouette can be observed. The method exploits envelope theory and a magnetic field model. Given one intensity image and the segmented silhouette in the image, the method proceeds without human intervention to produce the 3D model. In addition to allowing 3D model synthesis, the method's capability to yield a very compact description offers further utility. Application of the method to several real-world images is demonstrated.

  8. A Statistical Model for Synthesis of Detailed Facial Geometry

    OpenAIRE

    Golovinskiy, Aleksey; Matusik, Wojciech; Pfister, Hanspeter; Rusinkiewicz, Szymon; Funkhouser, Thomas

    2006-01-01

    Detailed surface geometry contributes greatly to the visual realism of 3D face models. However, acquiring high-resolution face geometry is often tedious and expensive. Consequently, most face models used in games, virtual reality, or computer vision look unrealistically smooth. In this paper, we introduce a new statistical technique for the analysis and synthesis of small three-dimensional facial features, such as wrinkles and pores. We acquire high-resolution face geometry for people across ...

  9. An Improved, Highly Efficient Method for the Synthesis of Bisphenols

    Directory of Open Access Journals (Sweden)

    L. S. Patil

    2011-01-01

    Full Text Available An efficient synthesis of bisphenols is described by condensation of substituted phenols with corresponding cyclic ketones in presence of cetyltrimethylammonium chloride and 3-mercaptopropionic acid as a catalyst in extremely high purity and yields.

  10. Peptide Synthesis Method and Solid Support for Use in the Method

    DEFF Research Database (Denmark)

    1994-01-01

    A method for the solid-phase synthesis of peptides or proteins in high yield and high purity uses a solid support consisting of a functionalized polystyrene-grafted polymer substrate, the grafted polystyrene chains being substantially non-cross-linked and having a chain molecular weight, not incl...... is immersed in a solution of optionally substituted styrene monomer in an alcohol such as methanol, the volume percentage of styrene in the solution preferably being about 30% v/v, and subjected to gamma irradiation....

  11. Shell model Monte Carlo methods

    International Nuclear Information System (INIS)

    Koonin, S.E.

    1996-01-01

    We review quantum Monte Carlo methods for dealing with large shell model problems. These methods reduce the imaginary-time many-body evolution operator to a coherent superposition of one-body evolutions in fluctuating one-body fields; resultant path integral is evaluated stochastically. We first discuss the motivation, formalism, and implementation of such Shell Model Monte Carlo methods. There then follows a sampler of results and insights obtained from a number of applications. These include the ground state and thermal properties of pf-shell nuclei, thermal behavior of γ-soft nuclei, and calculation of double beta-decay matrix elements. Finally, prospects for further progress in such calculations are discussed. 87 refs

  12. Doping and synthesis method effect on zirconium silicate conductivity

    Directory of Open Access Journals (Sweden)

    Monrós, G.

    2006-06-01

    Full Text Available The colour mechanisms of blue V- ZrSiO4 and yellow Pr- ZrSiO4 ceramic pigments which strongly depend on both fluorine addition and synthesis method, are still controversial. Complex impedance has been used as a useful tool to differentiate the materials as a function of the synthesis method, microstructure and observed colour, going deeply into the resolution of controversies about the nature of colours. Representative samples of these doping pigmenting systems prepared by both classical ceramic process and sol-gel method have been studied by complex impedance analysis. Vanadium doped zircon enhances resistivity and activation energy compared to undoped zircon powder and turkish blue vanadium-zircon obtained by addition of NaF shows the highest bulk resistivity. Activation energy and conductivity decrease for Praseodymium doped zircon compared to undoped zircon. This feature is in agreement with the presence of cationic vacancies on green vanadiumzircon samples due to V4+ and V5+ coexistence and praseodymium oxide inclusions on Pr- ZrSiO4 yellow pigment.

    El mecanismo del color en el azul de los pigmentos cerámicos V- ZrSiO4 y amarillo de Pr- ZrSiO4 cuyos tinos dependen mucho de la presencia de fluoruros así como del método de preparación esta controvertido en la literatura. La impedancia compleja se ha utilizado como una herramienta útil para diferenciar los materiales en función del método de síntesis, la microestructura y el color con el fin de profundizar en la resolución de las controversias. Se han preparado muestras representativas de ambos sistemas dopados mediante diferentes métodos de síntesis cerámico y sol-gel que se han estudiado por análisis de impedancia compleja. El circón dopado con vanadio aumenta su resistividad y sus energía de activación con referencia a la muestra no dopada y la muestra turquesa obtenida por adición de NaF presenta la mayor resistividad. Las muestras dopadas con praseodimio disminuyen

  13. Sound Cross-synthesis and Morphing Using Dictionary-based Methods

    DEFF Research Database (Denmark)

    Collins, Nick; Sturm, Bob L.

    2011-01-01

    Dictionary-based methods (DBMs) provide rich possibilities for new sound transformations; as the analysis dual to granular synthesis, audio signals are decomposed into `atoms', allowing interesting manipulations. We present various approaches to audio signal cross-synthesis and cross-analysis via...

  14. Making a difference: Towards a method for weighing the evidence in qualitative synthesis.

    NARCIS (Netherlands)

    Boeije, H.R.; van Wesel, F.; Alisic, E

    2011-01-01

    Objectives In a qualitative synthesis, primary qualitative studies are integrated to develop a theory or evidence-based interventions. Until now, the strength of the evidence in the primary studies has not been taken into account in the outcome of the qualitative synthesis. In this paper, a method

  15. Stochastic rainfall synthesis for urban applications using different regionalization methods

    Science.gov (United States)

    Callau Poduje, A. C.; Leimbach, S.; Haberlandt, U.

    2017-12-01

    The proper design and efficient operation of urban drainage systems require long and continuous rainfall series in a high temporal resolution. Unfortunately, these time series are usually available in a few locations and it is therefore suitable to develop a stochastic precipitation model to generate rainfall in locations without observations. The model presented is based on an alternating renewal process and involves an external and an internal structure. The members of these structures are described by probability distributions which are site specific. Different regionalization methods based on site descriptors are presented which are used for estimating the distributions for locations without observations. Regional frequency analysis, multiple linear regressions and a vine-copula method are applied for this purpose. An area located in the north-west of Germany is used to compare the different methods and involves a total of 81 stations with 5 min rainfall records. The site descriptors include information available for the whole region: position, topography and hydrometeorologic characteristics which are estimated from long term observations. The methods are compared directly by cross validation of different rainfall statistics. Given that the model is stochastic the evaluation is performed based on ensembles of many long synthetic time series which are compared with observed ones. The performance is as well indirectly evaluated by setting up a fictional urban hydrological system to test the capability of the different methods regarding flooding and overflow characteristics. The results show a good representation of the seasonal variability and good performance in reproducing the sample statistics of the rainfall characteristics. The copula based method shows to be the most robust of the three methods. Advantages and disadvantages of the different methods are presented and discussed.

  16. On the selection of optimized carbon nano tube synthesis method using analytic hierarchy process

    International Nuclear Information System (INIS)

    Besharati, M. K.; Afaghi Khatibi, A.; Akbari, M.

    2008-01-01

    Evidence from the early and late industrializes shows that technology, as the commercial application of scientific knowledge, has been a major driver of industrial and economic development. International technology transfer is now being recognized as having played an important role in the development of the most successful late industrializes of the second half of the twentieth Century. Our society stands to be significantly influenced by carbon nano tubes, shaped by nano tube applications in every aspect, just as silicon-based technology still shapes society today. Nano tubes can be formed in various structures using several different processing methods. In this paper, the synthesis methods used to produce nano tubes in industrial or laboratory scales are discussed and a comparison is made. A technical feasibility study is conducted by using the multi criteria decision-making model, namely Analytic Hierarchy Process. The article ends with a discussion of selecting the best method of Technology Transferring of Carbon Nano tubes to Iran

  17. PETRA. The Forecast Model. Synthesis report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    The aim of the PETRA project was to develop a model that could recreate the main aspects involved in the demand for travel. The attainment of this objective requires that the model system should retain a high degree of detail and be based on disaggregate models. This was both to ensure an accurate representation of the underlying behavioural intentions, and allow analysis of the underlying travel demand and related aspects across a number of dimensions. This has been achieved in all main respects. The model system is capable of close reproduction of the observed behaviour and generally responds as expected to changes, exhibiting consistent and plausible reactions. The dis-aggregation of the forecast population, according to the various criteria, allows the model to clearly illustrates the behavioural differences between different population segments. Thus, it seems reasonable to conclude that PETRA is capable of detailed analyses of the distributional and behavioural effects of policy changes. (au) EFP-94. 20 refs.

  18. Producing transparent PLZT ceramics using different synthesis method

    International Nuclear Information System (INIS)

    Dambekalne, M.; Antonova, M.; Livinsh, M.; Kalvane, A.; Plonska, M.; Garbarz-Glos, B.

    2004-01-01

    Full text: Ceramic samples of Pb 1-x La x (Zr 0.65 Ti 0.35 )O 3 (x 8, 9, 10) were prepared from powders being sintered by two methods: 1) peroxohydroxopolimer (PHP), where as precursors were used solutions of inorganic salts TiCl 4 , ZrOCl 4 ·8H 2 O, Pb(NO 3 ) 2 , La(NO 3 ) 3 ·6H 2 O); 2) sol-gel, using as precursors solutions of metal organic salts Pb(COOCH 3 ) 2 ·3H 2 O, La(COOCH 3 ) 3 ·1.5H 2 O, Zr(OCH 2 CH 2 CH 3 ) 4 , Ti(OCH 2 CH 2 CH 3 ) 4 . The thermal regimes for both powders were similar: synthesis at 600 0 C for 2 - 4h, obtaining amorphous nanopowder. Ceramic samples were produced by hot pressing at 1100 - 1200 0 C for 2 - 6h and pressure of 20Mpa.Optical transmittance of ceramic samples from PHP derived powders was higher than that from sol- gel derived. The transparency of poled plates with thickness of 0.3mm (wavelength λ = 630nm) was 67 - 69% and 56 - 59%, respectively. It can be explained by lack of technical support for sol-gel processing in atmosphere of neutral gas, as metal organic precursors are extremely sensitive to moisture of air. X-ray and DTA studies were used for powders. Dielectrics, ferroelectric and optical properties as well as studies of icrostructure were carried out for ceramic samples. The grain size of ceramics produced from PHP powders is 3- 4μ, for sol-gel ceramics less than 1μ

  19. SYNTHESIS OF NEURAL NETWORK MODEL REFERENCE CONTROLLER FOR AIMING AND STABILIZING SYSTEM

    Directory of Open Access Journals (Sweden)

    B.I. Kuznetsov

    2015-11-01

    Full Text Available The aim of this work is the synthesis of neural network reference model controller. The synthesis is performed in MATLAB for the problem of control of the aiming and stabilization system for the special equipment of moving objects. This paper presents the synthesis of the neural network reference model controller to meet the given performance characteristics of operation for the aiming and stabilization system for the special equipment of moving objects. Simulink tool in MATLAB is used to build the block diagram of double-loop neural network system of aiming and stabilization, where the reference model controller is put in the velocity loop and P-regulator is put in the position loop, with feedforward velocity control. Presented the method of synthesis of the neural network reference model controller that is implemented in the Neural Network Toolbox in MATLAB. System tests with the broad range of parameter values determined the key parameters defining the control quality. Optimal values of the key parameters were found to provide the highest control performance. System simulation and analysis of the obtained results is given.

  20. Text-in-context: a method for extracting findings in mixed-methods mixed research synthesis studies.

    Science.gov (United States)

    Sandelowski, Margarete; Leeman, Jennifer; Knafl, Kathleen; Crandell, Jamie L

    2013-06-01

    Our purpose in this paper is to propose a new method for extracting findings from research reports included in mixed-methods mixed research synthesis studies. International initiatives in the domains of systematic review and evidence synthesis have been focused on broadening the conceptualization of evidence, increased methodological inclusiveness and the production of evidence syntheses that will be accessible to and usable by a wider range of consumers. Initiatives in the general mixed-methods research field have been focused on developing truly integrative approaches to data analysis and interpretation. The data extraction challenges described here were encountered, and the method proposed for addressing these challenges was developed, in the first year of the ongoing (2011-2016) study: Mixed-Methods Synthesis of Research on Childhood Chronic Conditions and Family. To preserve the text-in-context of findings in research reports, we describe a method whereby findings are transformed into portable statements that anchor results to relevant information about sample, source of information, time, comparative reference point, magnitude and significance and study-specific conceptions of phenomena. The data extraction method featured here was developed specifically to accommodate mixed-methods mixed research synthesis studies conducted in nursing and other health sciences, but reviewers might find it useful in other kinds of research synthesis studies. This data extraction method itself constitutes a type of integration to preserve the methodological context of findings when statements are read individually and in comparison to each other. © 2012 Blackwell Publishing Ltd.

  1. Methods for testing transport models

    International Nuclear Information System (INIS)

    Singer, C.; Cox, D.

    1991-01-01

    Substantial progress has been made over the past year on six aspects of the work supported by this grant. As a result, we have in hand for the first time a fairly complete set of transport models and improved statistical methods for testing them against large databases. We also have initial results of such tests. These results indicate that careful application of presently available transport theories can reasonably well produce a remarkably wide variety of tokamak data

  2. A MODEL AND CONTROLLER REDUCTION METHOD FOR ROBUST CONTROL DESIGN.

    Energy Technology Data Exchange (ETDEWEB)

    YUE,M.; SCHLUETER,R.

    2003-10-20

    A bifurcation subsystem based model and controller reduction approach is presented. Using this approach a robust {micro}-synthesis SVC control is designed for interarea oscillation and voltage control based on a small reduced order bifurcation subsystem model of the full system. The control synthesis problem is posed by structured uncertainty modeling and control configuration formulation using the bifurcation subsystem knowledge of the nature of the interarea oscillation caused by a specific uncertainty parameter. Bifurcation subsystem method plays a key role in this paper because it provides (1) a bifurcation parameter for uncertainty modeling; (2) a criterion to reduce the order of the resulting MSVC control; and (3) a low order model for a bifurcation subsystem based SVC (BMSVC) design. The use of the model of the bifurcation subsystem to produce a low order controller simplifies the control design and reduces the computation efforts so significantly that the robust {micro}-synthesis control can be applied to large system where the computation makes robust control design impractical. The RGA analysis and time simulation show that the reduced BMSVC control design captures the center manifold dynamics and uncertainty structure of the full system model and is capable of stabilizing the full system and achieving satisfactory control performance.

  3. Voice Quality Modelling for Expressive Speech Synthesis

    Directory of Open Access Journals (Sweden)

    Carlos Monzo

    2014-01-01

    Full Text Available This paper presents the perceptual experiments that were carried out in order to validate the methodology of transforming expressive speech styles using voice quality (VoQ parameters modelling, along with the well-known prosody (F0, duration, and energy, from a neutral style into a number of expressive ones. The main goal was to validate the usefulness of VoQ in the enhancement of expressive synthetic speech in terms of speech quality and style identification. A harmonic plus noise model (HNM was used to modify VoQ and prosodic parameters that were extracted from an expressive speech corpus. Perception test results indicated the improvement of obtained expressive speech styles using VoQ modelling along with prosodic characteristics.

  4. Sound Synthesis of Objects Swinging through Air Using Physical Models

    Directory of Open Access Journals (Sweden)

    Rod Selfridge

    2017-11-01

    Full Text Available A real-time physically-derived sound synthesis model is presented that replicates the sounds generated as an object swings through the air. Equations obtained from fluid dynamics are used to determine the sounds generated while exposing practical parameters for a user or game engine to vary. Listening tests reveal that for the majority of objects modelled, participants rated the sounds from our model as plausible as actual recordings. The sword sound effect performed worse than others, and it is speculated that one cause may be linked to the difference between expectations of a sound and the actual sound for a given object.

  5. Novel Thiazole Derivatives of Medicinal Potential: Synthesis and Modeling

    Directory of Open Access Journals (Sweden)

    Nour E. A. Abdel-Sattar

    2017-01-01

    Full Text Available This paper reports on the synthesis of new thiazole derivatives that could be profitably exploited in medical treatment of tumors. Molecular electronic structures have been modeled within density function theory (DFT framework. Reactivity indices obtained from the frontier orbital energies as well as electrostatic potential energy maps are discussed and correlated with the molecular structure. X-ray crystallographic data of one of the new compounds is measured and used to support and verify the theoretical results.

  6. DNA and RNA Synthesis in Animal Cells in Culture--Methods for Use in Schools

    Science.gov (United States)

    Godsell, P. M.; Balls, M.

    1973-01-01

    Describes the experimental procedures used for detecting DNA and RNA synthesis in xenopus cells by autoradiography. The method described is suitable for senior high school laboratory classes or biology projects, if supervised by a teacher qualified to handle radioisotopes. (JR)

  7. Model-Based Synthesis of Locally Contingent Responses to Global Market Signals

    Directory of Open Access Journals (Sweden)

    Nicholas R. Magliocca

    2015-09-01

    Full Text Available Rural livelihoods and the land systems on which they depend are increasingly influenced by distant markets through economic globalization. Place-based analyses of land and livelihood system sustainability must then consider both proximate and distant influences on local decision-making. Thus, advancing land change theory in the context of economic globalization calls for a systematic understanding of the general processes as well as local contingencies shaping local responses to global signals. Synthesis of insights from place-based case studies is a path forward for developing such systematic knowledge. This paper introduces a generalized agent-based modeling framework for model-based synthesis to investigate the relative importance of structural versus agent-level factors in driving land-use and livelihood responses to changing global market signals. Six case-study sites that differed in environmental conditions, market access and influence, and livelihood settings were analyzed. Stronger market signals generally led to intensification and/or expansion of agriculture or increased non-farm labor, while changes in agents’ risk attitudes prompted heterogeneous local responses to global market signals. These results demonstrate model-based synthesis as a promising approach to overcome many of the challenges of current synthesis methods in land change science and identify generalized as well as locally contingent responses to global market signals.

  8. Synthesis and Modelling of Gold Nanostars with Tunable Morphology and Extinction Spectrum

    OpenAIRE

    Trigari, Silvana; Rindi, Alessio; Margheri, Giancarlo; Sottini, Stefano; Dellepiane, Giovanna; Giorgetti, Emilia

    2011-01-01

    We present a simple seed-less synthesis procedure to fabricate stable gold nanostars (AuNSs) with tunable extinction properties from the visible up to 1800 nm, depending on the average values of core size and branch length. The experimental results are compared with data from Finite Elements Method computations by using an approximated model of the fabricated branched systems. The theoretical computations highlight the existence of hot spots located on the tips of the nanostars even up to 180...

  9. Mathematical Model of Synthesis Catalyst with Local Reaction Centers

    Directory of Open Access Journals (Sweden)

    I. V. Derevich

    2017-01-01

    Full Text Available The article considers a catalyst granule with a porous ceramic passive substrate and point active centers on which an exothermic synthesis reaction occurs. A rate of the chemical reaction depends on the temperature according to the Arrhenius law. Heat is removed from the pellet surface in products of synthesis due to heat transfer. In our work we first proposed a model for calculating the steady-state temperature of a catalyst pellet with local reaction centers. Calculation of active centers temperature is based on the idea of self-consistent field (mean-field theory. At first, it is considered that powers of the reaction heat release at the centers are known. On the basis of the found analytical solution, which describes temperature distribution inside the granule, the average temperature of the reaction centers is calculated, which then is inserted in the formula for heat release. The resulting system of transcendental algebraic equations is transformed into a system of ordinary differential equations of relaxation type and solved numerically to achieve a steady-state value. As a practical application, the article considers a Fischer-Tropsch synthesis catalyst granule with active cobalt metallic micro-particles. Cobalt micro-particles are the centers of the exothermic reaction of hydrocarbons macromolecular synthesis. Synthesis occurs as a result of absorption of the components of the synthesis gas on metallic cobalt. The temperature distribution inside the granule for a single local center and reaction centers located on the same granule diameter is found. It was found that there is a critical temperature of reactor exceeding of which leads to significant local overheating of the centers - thermal explosion. The temperature distribution with the local reaction centers is qualitatively different from the granule temperature, calculated in the homogeneous approximation. It is shown that, in contrast to the homogeneous approximation, the

  10. Texture synthesis models and material perception in the visual periphery

    Science.gov (United States)

    Balas, Benjamin

    2015-03-01

    The feature vocabularies used to support texture synthesis algorithms are increasingly being used to examine various aspects of human visual perception. These algorithms offer both a rich set of features that are typically sufficient to capture the appearance of complex natural inputs and a means of carrying out psychophysical experiments using synthetic textures as a proxy for the transformations ostensibly carried out by the visual system when processing natural images using summary statistics. Texture synthesis algorithms have recently been successfully applied to a wide range of visual tasks including texture perception, visual crowding, visual search, among others. Presently, we used both nonparametric and parametric texture synthesis models to investigate the nature of material perception in the visual periphery. We asked participants to classify images of four natural materials (metal, stone, water, and wood) when briefly presented in the visual periphery and compared the errors made under these viewing conditions to the errors made when judging the material category of synthetic images made from the original targets. We found that the confusions made under these two scenarios were substantially different, suggesting that these particular models do not appear to account for material perception in the periphery.

  11. Robust Chemical Synthesis of Membrane Proteins through a General Method of Removable Backbone Modification.

    Science.gov (United States)

    Zheng, Ji-Shen; He, Yao; Zuo, Chao; Cai, Xiao-Ying; Tang, Shan; Wang, Zhipeng A; Zhang, Long-Hua; Tian, Chang-Lin; Liu, Lei

    2016-03-16

    Chemical protein synthesis can provide access to proteins with post-translational modifications or site-specific labelings. Although this technology is finding increasing applications in the studies of water-soluble globular proteins, chemical synthesis of membrane proteins remains elusive. In this report, a general and robust removable backbone modification (RBM) method is developed for the chemical synthesis of membrane proteins. This method uses an activated O-to-N acyl transfer auxiliary to install in the Fmoc solid-phase peptide synthesis process a RBM group with switchable reactivity toward trifluoroacetic acid. The method can be applied to versatile membrane proteins because the RBM group can be placed at any primary amino acid. With RBM, the membrane proteins and their segments behave almost as if they were water-soluble peptides and can be easily handled in the process of ligation, purification, and mass characterizations. After the full-length protein is assembled, the RBM group can be readily removed by trifluoroacetic acid. The efficiency and usefulness of the new method has been demonstrated by the successful synthesis of a two-transmembrane-domain protein (HCV p7 ion channel) with site-specific isotopic labeling and a four-transmembrane-domain protein (multidrug resistance transporter EmrE). This method enables practical synthesis of small- to medium-sized membrane proteins or membrane protein domains for biochemical and biophysical studies.

  12. The application of green chemistry methods in organophosphorus synthesis

    International Nuclear Information System (INIS)

    Odinets, Irina L; Matveeva, E V

    2012-01-01

    Data concerning the synthesis of organophosphorus compounds in ionic liquids, in water and under solvent-free conditions are considered and summarized. It is shown that this strategy, which complies with the definition of green chemistry, has advantages in terms of the rate of the process and the yields of target products as compared with syntheses in common organic solvents. The Wittig, Horner–Wadsworth–Emmons, Kabachnik–Fields, Arbuzov and Michaelis reactions are considered as examples. The bibliography includes 178 references.

  13. The application of green chemistry methods in organophosphorus synthesis

    Science.gov (United States)

    Odinets, Irina L.; Matveeva, E. V.

    2012-03-01

    Data concerning the synthesis of organophosphorus compounds in ionic liquids, in water and under solvent-free conditions are considered and summarized. It is shown that this strategy, which complies with the definition of green chemistry, has advantages in terms of the rate of the process and the yields of target products as compared with syntheses in common organic solvents. The Wittig, Horner-Wadsworth-Emmons, Kabachnik-Fields, Arbuzov and Michaelis reactions are considered as examples. The bibliography includes 178 references.

  14. Droplet-based microfluidic method for synthesis of microparticles

    CSIR Research Space (South Africa)

    Mbanjwa, MB

    2012-10-01

    Full Text Available biological applications such as drug delivery, cell encapsulation and tissue engineering[1]. GENERATION AND CONTROL OF MICRODROPLETS Water-in-oil (w/o) and oil-in-water (o/w) microdroplets and emulsions can be generated using microfluidic channels...: Generation and control of w/o droplets in flow focusing microfluidic channel MICROFLUIDIC-ASSISTED MICROPARTICLE SYNTHESIS Microparticles, such as biologically-important hydrogel micro- spheres, can be fabricated from various polymers...

  15. Population Synthesis Models for Normal Galaxies with Dusty Disks

    Directory of Open Access Journals (Sweden)

    Kyung-Won Suh

    2003-09-01

    Full Text Available To investigate the SEDs of galaxies considering the dust extinction processes in the galactic disks, we present the population synthesis models for normal galaxies with dusty disks. We use PEGASE (Fioc & Rocca-Volmerange 1997 to model them with standard input parameters for stars and new dust parameters. We find that the model results are strongly dependent on the dust parameters as well as other parameters (e.g. star formation history. We compare the model results with the observations and discuss about the possible explanations. We find that the dust opacity functions derived from studies of asymptotic giant branch stars are useful for modeling a galaxy with a dusty disk.

  16. An algorithm for a valved brass instrument synthesis environment using finite-difference time-domain methods with performance optimisation

    OpenAIRE

    Harrison, Reginald L.; Bilbao, Stefan; Perry, James

    2015-01-01

    This paper presents a physical modelling sound synthesis environment for the production of valved brass instrument sounds. The governing equations of the system are solved using finite-difference time-domain (FDTD) methods and the environment is implemented in the C programming language. Users of the environment can create their own custom instruments and are able to control player parameters such as lip frequency, mouth pressure and valve openings through the use of instrument and score file...

  17. Development of new methods in modern selective organic synthesis: preparation of functionalized molecules with atomic precision

    International Nuclear Information System (INIS)

    Ananikov, V P; Khemchyan, L L; Ivanova, Yu V; Dilman, A D; Levin, V V; Bukhtiyarov, V I; Sorokin, A M; Prosvirin, I P; Romanenko, A V; Simonov, P A; Vatsadze, S Z; Medved'ko, A V; Nuriev, V N; Nenajdenko, V G; Shmatova, O I; Muzalevskiy, V M; Koptyug, I V; Kovtunov, K V; Zhivonitko, V V; Likholobov, V A

    2014-01-01

    The challenges of the modern society and the growing demand of high-technology sectors of industrial production bring about a new phase in the development of organic synthesis. A cutting edge of modern synthetic methods is introduction of functional groups and more complex structural units into organic molecules with unprecedented control over the course of chemical transformation. Analysis of the state-of-the-art achievements in selective organic synthesis indicates the appearance of a new trend — the synthesis of organic molecules, biologically active compounds, pharmaceutical substances and smart materials with absolute selectivity. Most advanced approaches to organic synthesis anticipated in the near future can be defined as 'atomic precision' in chemical reactions. The present review considers selective methods of organic synthesis suitable for transformation of complex functionalized molecules under mild conditions. Selected key trends in the modern organic synthesis are considered including the preparation of organofluorine compounds, catalytic cross-coupling and oxidative cross-coupling reactions, atom-economic addition reactions, methathesis processes, oxidation and reduction reactions, synthesis of heterocyclic compounds, design of new homogeneous and heterogeneous catalytic systems, application of photocatalysis, scaling up synthetic procedures to industrial level and development of new approaches to investigation of mechanisms of catalytic reactions. The bibliography includes 840 references

  18. Computational fluid dynamic modeling of the flame spray pyrolysis process for silica nanopowder synthesis

    International Nuclear Information System (INIS)

    Olivas-Martinez, Miguel; Sohn, Hong Yong; Jang, Hee Dong; Rhee, Kang-In

    2015-01-01

    A computational fluid dynamic model that couples the fluid dynamics with various processes involving precursor droplets and product particles during the flame spray pyrolysis (FSP) synthesis of silica nanopowder from volatile precursors is presented. The synthesis of silica nanopowder from tetraethylorthosilicate and tetramethylorthosilicate in bench- and pilot-scale FSP reactors, with the ultimate purpose of industrial-scale production, was simulated. The transport and evaporation of liquid droplets are simulated from the Lagrangian viewpoint. The quadrature method of moments is used to solve the population balance equation for particles undergoing homogeneous nucleation and Brownian collision. The nucleation rate is computed based on the rates of thermal decomposition and oxidation of the precursor with no adjustable parameters. The computed results show that the model is capable of reproducing the magnitude as well as the variations of the average particle diameter with different experimental conditions using a single value of the collision efficiency factor α for a given reactor size

  19. Model studies of methanol synthesis on copper catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, J.; Nakamura, I.; Uchijima, T. [Univ. of Tsukuba, Ibaraki (Japan); Watanabe, T. [Research Inst. of Innovative Technology for Earth, Kyoto (Japan); Fujitani, T. [National Inst. for Resources and Environment, Ibaraki (Japan)

    1996-12-31

    The synthesis of methanol by the hydrogenation of CO{sub 2} over Zn-deposited and Zn-free copper surfaces has been studied using an XPS apparatus combined with a high-pressure flow reactor (18 atm). It was shown that the Zn deposited on Cu(111) and poly-Cu acted as a promoter for methanol synthesis, while the Zn on Cu(110) and Cu(100) had no such a promotional effect. The turnover frequency (TOF) for Zn/Cu(111) linearly increased with Zn coverage below {Theta}Zn--0.19, and then decreased above {Theta}Zn=0.20. The optimum TOF obtained at {Theta}Zn--0-19 was thirteen-fold larger than TOF for the Zn-free Cu(111) surface. On the other hand, no promotional effect of Zn was observed for the reverse water-gas shift reaction on all the surfaces. The results indicate the formation of special sites for methanol synthesis on Zn/Cu(111). The Zn-deposited Cu(111) can be regarded as a model of Cu/ZnO catalysts because the TOF and the activation energy for methanol formation over the Zn-deposited Cu(111) were in fairly good agreement with those for the Cu/ZnO powder catalysts. The post-reaction surface analysis by XPS showed the formation of formate species (HCOOa). The formate coverage was proportional to the activity for methanol formation below {Theta}Zn=0.20, suggesting that the hydrogenation of the formate species is the rate-determining step of methanol formation. The formate species was stabilized by Zn species on Cu(111) in the absence of ZnO species. STM results on the Zn-deposited Cu(111) suggested the formation of a Cu-Zn surface alloy. The presence of special sites for methanol synthesis was also indicated in the results of powder catalysts.

  20. Ion transport membrane reactor systems and methods for producing synthesis gas

    Science.gov (United States)

    Repasky, John Michael

    2015-05-12

    Embodiments of the present invention provide cost-effective systems and methods for producing a synthesis gas product using a steam reformer system and an ion transport membrane (ITM) reactor having multiple stages, without requiring inter-stage reactant injections. Embodiments of the present invention also provide techniques for compensating for membrane performance degradation and other changes in system operating conditions that negatively affect synthesis gas production.

  1. How the Method of Synthesis Governs the Local and Global Structure of Zinc Aluminum Layered Double Hydroxides

    DEFF Research Database (Denmark)

    Puschparaj, Suraj S. C.; Forano, Claude; Prevot, Vanessa

    2015-01-01

    Seven zinc aluminum layered double hydroxides (ZnAl LDHs), [Zn1-xAlx (OH)2Ax,nH2O] A = NO3-, Cl- or CO32-, prepared by the urea and co-precipitation synthesis methods were investigated to determine how synthesis parameters (pH, metal ion concentration and post synthesis treatment) affect the local...

  2. Synthesis-condition dependence of carbon nanotube growth by alcohol catalytic chemical vapor deposition method

    Directory of Open Access Journals (Sweden)

    Nobuhito Inami et al

    2007-01-01

    Full Text Available We report the dependence of growth yield of single-walled carbon nanotubes (SWNTs on heat-treatment time and catalyst film thickness by the alcohol catalytic chemical vapor deposition method. Three types of heat-treatment, synthesis of 30 min, synthesis of 30 min after annealing of 30 min, and synthesis of 60 min, were investigated. Thickness of Co catalyst film was varied from 1 to 10 nm. In the case of thinner Co film less than 3 nm, long synthesis time of 60 min is favorable for the effective SWNT growth, because of the small amount of Co catalyst. In the case of thicker Co film more than 3 nm, an amount of grown SWNTs by 30 min synthesis after 30 min annealing and by 60 min synthesis was much higher than that by 30 min synthesis without annealing, showing that total heat-treatment time of 60 min is important for the SWNT growth. Results suggest that the conversion from the thicker film of Co to nano-particle which acts as catalyst takes place during the first 30 min.

  3. Development of a Probabilistic Dynamic Synthesis Method for the Analysis of Nondeterministic Structures

    Science.gov (United States)

    Brown, A. M.

    1998-01-01

    Accounting for the statistical geometric and material variability of structures in analysis has been a topic of considerable research for the last 30 years. The determination of quantifiable measures of statistical probability of a desired response variable, such as natural frequency, maximum displacement, or stress, to replace experience-based "safety factors" has been a primary goal of these studies. There are, however, several problems associated with their satisfactory application to realistic structures, such as bladed disks in turbomachinery. These include the accurate definition of the input random variables (rv's), the large size of the finite element models frequently used to simulate these structures, which makes even a single deterministic analysis expensive, and accurate generation of the cumulative distribution function (CDF) necessary to obtain the probability of the desired response variables. The research presented here applies a methodology called probabilistic dynamic synthesis (PDS) to solve these problems. The PDS method uses dynamic characteristics of substructures measured from modal test as the input rv's, rather than "primitive" rv's such as material or geometric uncertainties. These dynamic characteristics, which are the free-free eigenvalues, eigenvectors, and residual flexibility (RF), are readily measured and for many substructures, a reasonable sample set of these measurements can be obtained. The statistics for these rv's accurately account for the entire random character of the substructure. Using the RF method of component mode synthesis, these dynamic characteristics are used to generate reduced-size sample models of the substructures, which are then coupled to form system models. These sample models are used to obtain the CDF of the response variable by either applying Monte Carlo simulation or by generating data points for use in the response surface reliability method, which can perform the probabilistic analysis with an order of

  4. Second-strand cDNA synthesis: classical method

    International Nuclear Information System (INIS)

    Gubler, U.

    1987-01-01

    The classical scheme for the synthesis of double-stranded cDNA as it was reported in 1976 is described. Reverse transcription of mRNA with oligo(dT) as the primer generates first strands with a small loop at the 3' end of the cDNA (the end that corresponds to the 5' end of the mRNA). Subsequent removal of the mRNA by alkaline hydrolysis leaves single-stranded cDNA molecules again with a small 3' loop. This loop can be used by either reverse transcriptase or Klenow fragment of DNA polymerase I as a primer for second-strand synthesis. The resulting products are double-stranded cDNA molecules that are covalently closed at the end corresponding to the 5' end of the original mRNA. Subsequent cleavage of the short piece of single-stranded cDNA within the loop with the single-strand-specific S 1 nuclease generate open double-stranded molecules that can be used for molecular cloning in plasmids or in phage. Useful variations of this scheme have been described

  5. Bayesian data augmentation methods for the synthesis of qualitative and quantitative research findings

    Science.gov (United States)

    Crandell, Jamie L.; Voils, Corrine I.; Chang, YunKyung; Sandelowski, Margarete

    2010-01-01

    The possible utility of Bayesian methods for the synthesis of qualitative and quantitative research has been repeatedly suggested but insufficiently investigated. In this project, we developed and used a Bayesian method for synthesis, with the goal of identifying factors that influence adherence to HIV medication regimens. We investigated the effect of 10 factors on adherence. Recognizing that not all factors were examined in all studies, we considered standard methods for dealing with missing data and chose a Bayesian data augmentation method. We were able to summarize, rank, and compare the effects of each of the 10 factors on medication adherence. This is a promising methodological development in the synthesis of qualitative and quantitative research. PMID:21572970

  6. Nebular Continuum and Line Emission in Stellar Population Synthesis Models

    Science.gov (United States)

    Byler, Nell; Dalcanton, Julianne J.; Conroy, Charlie; Johnson, Benjamin D.

    2017-05-01

    Accounting for nebular emission when modeling galaxy spectral energy distributions (SEDs) is important, as both line and continuum emissions can contribute significantly to the total observed flux. In this work, we present a new nebular emission model integrated within the Flexible Stellar Population Synthesis code that computes the line and continuum emission for complex stellar populations using the photoionization code Cloudy. The self-consistent coupling of the nebular emission to the matched ionizing spectrum produces emission line intensities that correctly scale with the stellar population as a function of age and metallicity. This more complete model of galaxy SEDs will improve estimates of global gas properties derived with diagnostic diagrams, star formation rates based on Hα, and physical properties derived from broadband photometry. Our models agree well with results from other photoionization models and are able to reproduce observed emission from H II regions and star-forming galaxies. Our models show improved agreement with the observed H II regions in the Ne III/O II plane and show satisfactory agreement with He II emission from z = 2 galaxies, when including rotating stellar models. Models including post-asymptotic giant branch stars are able to reproduce line ratios consistent with low-ionization emission regions. The models are integrated into current versions of FSPS and include self-consistent nebular emission predictions for MIST and Padova+Geneva evolutionary tracks.

  7. An efficient one-pot four-segment condensation method for protein chemical synthesis.

    Science.gov (United States)

    Tang, Shan; Si, Yan-Yan; Wang, Zhi-Peng; Mei, Kun-Rong; Chen, Xin; Cheng, Jing-Yuan; Zheng, Ji-Shen; Liu, Lei

    2015-05-04

    Successive peptide ligation using a one-pot method can improve the efficiency of protein chemical synthesis. Although one-pot three-segment ligation has enjoyed widespread application, a robust method for one-pot four-segment ligation had to date remained undeveloped. Herein we report a new one-pot multisegment peptide ligation method that can be used to condense up to four segments with operational simplicity and high efficiency. Its practicality is demonstrated by the one-pot four-segment synthesis of a plant protein, crambin, and a human chemokine, hCCL21. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. A probabilistic model for component-based shape synthesis

    KAUST Repository

    Kalogerakis, Evangelos

    2012-07-01

    We present an approach to synthesizing shapes from complex domains, by identifying new plausible combinations of components from existing shapes. Our primary contribution is a new generative model of component-based shape structure. The model represents probabilistic relationships between properties of shape components, and relates them to learned underlying causes of structural variability within the domain. These causes are treated as latent variables, leading to a compact representation that can be effectively learned without supervision from a set of compatibly segmented shapes. We evaluate the model on a number of shape datasets with complex structural variability and demonstrate its application to amplification of shape databases and to interactive shape synthesis. © 2012 ACM 0730-0301/2012/08-ART55.

  9. Physically Inspired Models for the Synthesis of Stiff Strings with Dispersive Waveguides

    Directory of Open Access Journals (Sweden)

    Testa I

    2004-01-01

    Full Text Available We review the derivation and design of digital waveguides from physical models of stiff systems, useful for the synthesis of sounds from strings, rods, and similar objects. A transform method approach is proposed to solve the classic fourth-order equations of stiff systems in order to reduce it to two second-order equations. By introducing scattering boundary matrices, the eigenfrequencies are determined and their dependency is discussed for the clamped, hinged, and intermediate cases. On the basis of the frequency-domain physical model, the numerical discretization is carried out, showing how the insertion of an all-pass delay line generalizes the Karplus-Strong algorithm for the synthesis of ideally flexible vibrating strings. Knowing the physical parameters, the synthesis can proceed using the generalized structure. Another point of view is offered by Laguerre expansions and frequency warping, which are introduced in order to show that a stiff system can be treated as a nonstiff one, provided that the solutions are warped. A method to compute the all-pass chain coefficients and the optimum warping curves from sound samples is discussed. Once the optimum warping characteristic is found, the length of the dispersive delay line to be employed in the simulation is simply determined from the requirement of matching the desired fundamental frequency. The regularization of the dispersion curves by means of optimum unwarping is experimentally evaluated.

  10. Method for innovative synthesis-design of chemical process flowsheets

    DEFF Research Database (Denmark)

    Kumar Tula, Anjan; Gani, Rafiqul

    is available, rigorous simulation is performed to validate the synthesis-design. Note that since the flowsheet is synthesized and the operations in the flowsheet designed to match a set of design targets, there are no iterations involved as the final flowsheet is among the best, if not the best. In this paper...... of chemical processes, where, chemical process flowsheets could be synthesized in the same way as atoms or groups of atoms are synthesized to form molecules in computer aided molecular design (CAMD) techniques [4]. That, from a library of building blocks (functional process-groups) and a set of rules to join...... and selected for further analysis. In the next stage, the design parameters for the operations of the flowsheet are established through reverse engineering approaches based on driving forces available for each operation. In the final stage, when all the necessary information for a rigorous process simulation...

  11. Comparative study of synthesis and reduction methods for graphene oxide

    KAUST Repository

    Alazmi, Amira

    2016-05-14

    Graphene oxide (GO) and reduced graphene oxide (rGO) have congregated much interest as promising active materials for a variety of applications such as electrodes for supercapacitors. Yet, partially given the absence of comparative studies in synthesis methodologies, a lack of understanding persists on how to best tailor these materials. In this work, the effect of using different graphene oxidation-reduction strategies in the structure and chemistry of rGOs is systematically discussed. Two of the most popular oxidation routes in the literature were used to obtain GO. Subsequently, two sets of rGO powders were synthesised employing three different reduction routes, totalling six separate products. It is shown that the extension of the structural rearrangement in rGOs is not just dependent on the reduction step but also on the approach followed for the initial graphite oxidation.

  12. Synthesis of alumina powders by precipitation method and solvothermal treatment

    International Nuclear Information System (INIS)

    Politchuk, J.O.; Lima, N.B.; Lazar, D.R.R.; Ussui, V.; Yoshito, W.K.

    2012-01-01

    The improvement of alumina powders synthesis processes has been focused on the preparation of ceramic powders with well defined crystalline structure and with high specific surface area and nanometric particle size without formation of hard agglomerates. For this purpose the precipitation step should be studied and and also the temperature of alumina crystallization should be reduced. The aim of this study was to obtain alumina powders by hydroxide precipitation with ammonia in the presence of cationic surfactant, followed by solvothermal treatment and calcination. The powders were characterized by TG/DTA, X-ray diffraction, surface area measurements by gas adsorption (BET) and scanning electron microscopy. The results showed that powders produced by solvothermal treatment without surfactant have higher crystallinity. However the presence of CTAB enhances 240% the specific surface area compared with powders produced without this reagent (author)

  13. A Direction Finding Method with A 3-D Array Based on Aperture Synthesis

    Science.gov (United States)

    Li, Shiwen; Chen, Liangbing; Gao, Zhaozhao; Ma, Wenfeng

    2018-01-01

    Direction finding for electronic warfare application should provide a wider field of view as possible. But the maximum unambiguous field of view for conventional direction finding methods is a hemisphere. It cannot distinguish the direction of arrival of the signals from the back lobe of the array. In this paper, a full 3-D direction finding method based on aperture synthesis radiometry is proposed. The model of the direction finding system is illustrated, and the fundamentals are presented. The relationship between the outputs of the measurements of a 3-D array and the 3-D power distribution of the point sources can be represented by a 3-D Fourier transform, and then the 3-D power distribution of the point sources can be reconstructed by an inverse 3-D Fourier transform. And in order to display the 3-D power distribution of the point sources conveniently, the whole spherical distribution is represented by two 2-D circular distribution images, one of which is for the upper hemisphere, and the other is for the lower hemisphere. Then a numeric simulation is designed and conducted to demonstrate the feasibility of the method. The results show that the method can estimate the arbitrary direction of arrival of the signals in the 3-D space correctly.

  14. Synthesis of gelatin nano/submicron particles by binary nonsolvent aided coacervation (BNAC) method.

    Science.gov (United States)

    Patra, Shamayita; Basak, Piyali; Tibarewala, D N

    2016-02-01

    A newly developed modified coacervation method is utilized to synthesize gelatin nano/submicron particles (GN/SPs) as a drug carrier. Binary nonsolvent aided coacervation (BNAC) method is a modified single step coacervation method, which has yielded approximately a threefold lower particle size and higher average yield in terms of weight percentage of around 94% in comparison to the conventional phase separation methods. In this study 0.5% (w/v) gelatin aqueous solution with a binary nonsolvent system of acetone and ethanol was used. Nanoparticle synthesis was optimized with respect to nonsolvent system type and pH. pH7 has resulted a minimum particle size of 55.67 (±43.74) nm in anhydrous medium along with a swollen particle size of 776nm (±38.57) in aqueous medium with a zeta potential of (-16.3±3.51) mV in aqueous medium. Swelling ratio of 13.95 confirms the crosslinked hydrogel nature of the particles. Furthermore, drug loading efficiency of the gelatin particles prepared at 7pH was observed with nitrofurazone as the model drug. Results of drug release study indicate the potential use of GN/SPs as drug loading matrix for wound management such as burn wound management. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Synthesis of borohydrides of rare earth metals by mechanic-chemical methods

    International Nuclear Information System (INIS)

    Gafurov, B.A.; Nasrulloeva, D.Kh.; Khakyorov, I.Z.; Saidov, V.Ya.

    2010-01-01

    Present article is devoted to synthesis of borohydrides of rare earth metals by mechanic-chemical methods. The borohydrides of rare earth metals were obtained by means of mechanic-chemical methods. Physicochemical properties of obtained lanthanoid borohydrides were studied by means of X-ray phase analysis.

  16. Analytical methods used at model facility

    International Nuclear Information System (INIS)

    Wing, N.S.

    1984-01-01

    A description of analytical methods used at the model LEU Fuel Fabrication Facility is presented. The methods include gravimetric uranium analysis, isotopic analysis, fluorimetric analysis, and emission spectroscopy

  17. Model-based synthesis of locally contingent responses to global market signals

    Science.gov (United States)

    Magliocca, N. R.

    2015-12-01

    Rural livelihoods and the land systems on which they depend are increasingly influenced by distant markets through economic globalization. Place-based analyses of land and livelihood system sustainability must then consider both proximate and distant influences on local decision-making. Thus, advancing land change theory in the context of economic globalization calls for a systematic understanding of the general processes as well as local contingencies shaping local responses to global signals. Synthesis of insights from place-based case studies of land and livelihood change is a path forward for developing such systematic knowledge. This paper introduces a model-based synthesis approach to investigating the influence of local socio-environmental and agent-level factors in mediating land-use and livelihood responses to changing global market signals. A generalized agent-based modeling framework is applied to six case-study sites that differ in environmental conditions, market access and influence, and livelihood settings. The largest modeled land conversions and livelihood transitions to market-oriented production occurred in sties with relatively productive agricultural land and/or with limited livelihood options. Experimental shifts in the distributions of agents' risk tolerances generally acted to attenuate or amplify responses to changes in global market signals. Importantly, however, responses of agents at different points in the risk tolerance distribution varied widely, with the wealth gap growing wider between agents with higher or lower risk tolerance. These results demonstrate model-based synthesis is a promising approach to overcome many of the challenges of current synthesis methods in land change science, and to identify generalized as well as locally contingent responses to global market signals.

  18. Design and synthesis of two new substrates for model ribosomal reactions

    International Nuclear Information System (INIS)

    Bayryamov, S.; Vassilev, N.; Petkov, D.

    2008-01-01

    2 ' /3 ' -O-[2-N-p-nitrobenzoyl, 5-N-tert-butyloxycarbonyl-L-ornithinyl] 5 ' -O- pivaloyladenosine :(2 ' /3 ' -O-[ Bz (NO 2 )-Orn (Boc )]-5 ' -O-Piv-Ado) 1and its deoxy analogue - 3 ' -O-[2-N-p-nitrobenzoyl , 5-N-tert-butyloxycarbonyl-L-ornithinyl] 5 ' -O- pivaloyl 2 ' -deoxyadenosine: (3 ' -O-[Bz(NO 2 )-Orn(Boc)]-5 ' -O-Piv-2 ' -dAdo) 2 were synthesized as substrates for a model ribosome reaction. They were used to demonstrate the crucial role of A76 2 ' -OH of peptidyl-tRNA in the rate acceleration of peptide bond formation during protein biosynthesis. The synthesis was carried out using suitable combinations of the methods of peptide, nucleoside and nucleotide synthesis. (authors)

  19. Modeling of composite synthesis in conditions of controlled thermal explosion

    Science.gov (United States)

    Kukta, Yaroslav; Knyazeva, Anna

    2017-12-01

    The paper proposes the model for the titanium-based composite synthesis from powders of titanium and carbon of non-stoichiometric composition. The model takes into account the mixture heating from chamber walls, the dependence of liquidus and solidus temperatures on the composition of reacting mixture and the formation of possible irreversible phases. The reaction retardation by the reaction product is taken into consideration in kinetic laws. As an example, the results of temperature and conversion level calculation are presented for the system Ti-C with the summary reaction for different temperatures of chamber walls heating. It was revealed that the reaction retardation being the reaction product can be the cause of incomplete conversion in the thermal explosion conditions. Non-stoichiometric composition leads to the conditions of degenerated mode when some additional heating is necessary to complete the reaction.

  20. Modelling of the enzymatic kinetically controlled synthesis of cephalexin

    NARCIS (Netherlands)

    Schroën, C.G.P.H.; Fretz, C.B.; Bruin, de V.H.; Berendsen, W.; Moody, H.M.; Roos, E.C.; Roon, van J.L.; Kroon, P.J.; Strubel, M.; Janssen, A.E.M.; Tramper, J.

    2002-01-01

    In this study the influence of diffusion limitation on enzymatic kinetically controlled cephalexin synthesis from phenylglycine amide and 7-aminodeacetoxycephalosporinic acid (7-ADCA) was investigated systematically. It was found that if diffusion limitation occurred, both the synthesis/hydrolysis

  1. A Method of Polymer Design and Synthesis for Selective Infrared Energy Absorption.

    Science.gov (United States)

    1982-06-18

    AD-AL17 485 CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) SCHAMPAIGN IL F/6 7/3 A METHOD OF POLYMER OESIGN AND SYNTHESIS FOR SELECTIVE INFRARED--ETC(U...JUN A2 A SM ITH ULASSIFIED N 11111 .0 ;11L.5I 1111.2 1.25 11.4 MICROCOPY RESOLUTION TEST CHART SM1ITH N A METHOD OF IPOLYU DESIGN AND SYNTHESIS FOR...nuclear magnetic resonanes The translations of vibrational or rotational energy via mas dis- placement occur as bond stretching (symetric and asymetric

  2. Systematic process synthesis and design methods for cost effective waste minimization

    International Nuclear Information System (INIS)

    Biegler, L.T.; Grossman, I.E.; Westerberg, A.W.

    1995-01-01

    We present progress on our work to develop synthesis methods to aid in the design of cost effective approaches to waste minimization. Work continues to combine the approaches of Douglas and coworkers and of Grossmann and coworkers on a hierarchical approach where bounding information allows it to fit within a mixed integer programming approach. We continue work on the synthesis of reactors and of flexible separation processes. In the first instance, we strive for methods we can use to reduce the production of potential pollutants, while in the second we look for ways to recover and recycle solvents

  3. Metabolic modeling of synthesis gas fermentation in bubble column reactors.

    Science.gov (United States)

    Chen, Jin; Gomez, Jose A; Höffner, Kai; Barton, Paul I; Henson, Michael A

    2015-01-01

    A promising route to renewable liquid fuels and chemicals is the fermentation of synthesis gas (syngas) streams to synthesize desired products such as ethanol and 2,3-butanediol. While commercial development of syngas fermentation technology is underway, an unmet need is the development of integrated metabolic and transport models for industrially relevant syngas bubble column reactors. We developed and evaluated a spatiotemporal metabolic model for bubble column reactors with the syngas fermenting bacterium Clostridium ljungdahlii as the microbial catalyst. Our modeling approach involved combining a genome-scale reconstruction of C. ljungdahlii metabolism with multiphase transport equations that govern convective and dispersive processes within the spatially varying column. The reactor model was spatially discretized to yield a large set of ordinary differential equations (ODEs) in time with embedded linear programs (LPs) and solved using the MATLAB based code DFBAlab. Simulations were performed to analyze the effects of important process and cellular parameters on key measures of reactor performance including ethanol titer, ethanol-to-acetate ratio, and CO and H2 conversions. Our computational study demonstrated that mathematical modeling provides a complementary tool to experimentation for understanding, predicting, and optimizing syngas fermentation reactors. These model predictions could guide future cellular and process engineering efforts aimed at alleviating bottlenecks to biochemical production in syngas bubble column reactors.

  4. Aseismic optimization of nonlinear joint elements in boiler plant structures based on substructure synthesis method

    International Nuclear Information System (INIS)

    Nishida, E.; Suzuki, K.; Yasuda, T.; Ohwa, Y.

    1993-01-01

    This paper deals with an optimum design method for joint elements in boiler plant structures which are excited by earthquakes. Characteristics of joint elements which connect the boiler and its supporting structure, are supposed to be viscoelastic, elasto-plastic, or a combination of both. Considering the expansion of this study to an active or semi-active aseismic structural control of joint elements, the structures are modeled with the aid of block diagram. In order to improve the efficiency of calculation, substructure synthesis method is introduced. Time-domain optimization is carried out using a nonlinear programming technique. To prevent seismic damage of pipes and ducts, limitations for relative displacements between the boiler and its supporting structure is introduced is inequality constraints. Elasto-plasticity and viscoelasticity of joint elements are simulated by a combination of a spring, a Coulomb friction, and a dashpot. These joint element characteristics are optimized to minimize seismic time-response of the structures. This method is applied to actual boiler plant structures and has proven to be effective and practical for aseismic designs of boiler plant structures

  5. Energy models: methods and trends

    International Nuclear Information System (INIS)

    Reuter, A.; Kuehner, R.; Wohlgemuth, N.

    1996-01-01

    Energy environmental and economical systems do not allow for experimentation since this would be dangerous, too expensive or even impossible. Instead, mathematical models are applied for energy planning. Experimenting is replaced by varying the structure and some parameters of 'energy models', computing the values of depending parameters, comparing variations, and interpreting their outcomings. Energy models are as old as computers. In this article the major new developments in energy modeling will be pointed out. We distinguish between 3 reasons of new developments: progress in computer technology, methodological progress and novel tasks of energy system analysis and planning

  6. Candidate Prediction Models and Methods

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Madsen, Henrik

    2005-01-01

    This document lists candidate prediction models for Work Package 3 (WP3) of the PSO-project called ``Intelligent wind power prediction systems'' (FU4101). The main focus is on the models transforming numerical weather predictions into predictions of power production. The document also outlines...

  7. Methods for the thematic synthesis of qualitative research in systematic reviews

    Directory of Open Access Journals (Sweden)

    Harden Angela

    2008-07-01

    Full Text Available Abstract Background There is a growing recognition of the value of synthesising qualitative research in the evidence base in order to facilitate effective and appropriate health care. In response to this, methods for undertaking these syntheses are currently being developed. Thematic analysis is a method that is often used to analyse data in primary qualitative research. This paper reports on the use of this type of analysis in systematic reviews to bring together and integrate the findings of multiple qualitative studies. Methods We describe thematic synthesis, outline several steps for its conduct and illustrate the process and outcome of this approach using a completed review of health promotion research. Thematic synthesis has three stages: the coding of text 'line-by-line'; the development of 'descriptive themes'; and the generation of 'analytical themes'. While the development of descriptive themes remains 'close' to the primary studies, the analytical themes represent a stage of interpretation whereby the reviewers 'go beyond' the primary studies and generate new interpretive constructs, explanations or hypotheses. The use of computer software can facilitate this method of synthesis; detailed guidance is given on how this can be achieved. Results We used thematic synthesis to combine the studies of children's views and identified key themes to explore in the intervention studies. Most interventions were based in school and often combined learning about health benefits with 'hands-on' experience. The studies of children's views suggested that fruit and vegetables should be treated in different ways, and that messages should not focus on health warnings. Interventions that were in line with these suggestions tended to be more effective. Thematic synthesis enabled us to stay 'close' to the results of the primary studies, synthesising them in a transparent way, and facilitating the explicit production of new concepts and hypotheses

  8. Methanol synthesis catalyst manufacturing using the green solid-state method

    Directory of Open Access Journals (Sweden)

    Neda Mirhosseini

    2017-01-01

    Full Text Available In this research study, methanol synthesis catalysts were manufactured with various mole ratios of metal carbonates (zinc, copper and aluminum carbonate and ammonium hydrogen carbonate via a green solid-state method that employed a ball mill apparatus. Some parameters for the catalyst preparation, such as Al mole percent, Cu/Zn mole ratio, rotations milling speeds and aging time, were optimized to obtain the maximum catalyst activity. The prepared catalysts were compared with the best quality industrial catalyst under the same temperature and pressure condition in a titanium tabular fixed bed reactor. This novel method has many advantages in comparison to the conventional method. The main advantage of the solid-state method is that the methanol synthesis catalyst can be produced without using solvent. Furthermore, this new method reduces operating costs due to the elimination of the filtration and washing steps. Methanol synthesis catalytic activity was maximized at an optimized mole ratio of Cu/Zn of 1.9234 and an Al mole percent of 8 at the maximum grinding speed (450 rpm during an aging time of 30 min, which showed higher activity (240 gCH3OH/kg cat.h in comparison with an industrial catalyst sample (218 gCH3OH/kg cat.h. The production of a green catalyst, which requires less water and results in higher catalyst activity, can be widely used for methanol synthesis catalytic applications.

  9. Immobilization methods for the rapid total chemical synthesis of proteins on microtiter plates.

    Science.gov (United States)

    Zitterbart, Robert; Krumrey, Michael; Seitz, Oliver

    2017-07-01

    The chemical synthesis of proteins typically involves the solid-phase peptide synthesis of unprotected peptide fragments that are stitched together in solution by native chemical ligation (NCL). The process is slow, and throughput is limited because of the need for repeated high performance liquid chromatography purification steps after both solid-phase peptide synthesis and NCL. With an aim to provide faster access to functional proteins and to accelerate the functional analysis of synthetic proteins by parallelization, we developed a method for the high performance liquid chromatography-free synthesis of proteins on the surface of microtiter plates. The method relies on solid-phase synthesis of unprotected peptide fragments, immobilization of the C-terminal fragment and on-surface NCL with an unprotected peptide thioester in crude form. Herein, we describe the development of a suitable immobilization chemistry. We compared (i) formation of nickel(II)-oligohistidine complexes, (ii) Cu-based [2 + 3] alkine-azide cycloaddition and (iii) hydrazone ligation. The comparative study identified the hydrazone ligation as most suitable. The sequence of immobilization via hydrazone ligation, on-surface NCL and radical desulfurization furnished the targeted SH3 domains in near quantitative yield. The synthetic proteins were functional as demonstrated by an on-surface fluorescence-based saturation binding analysis. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

  10. Method for synthesis of titanium dioxide nanotubes using ionic liquids

    Science.gov (United States)

    Qu, Jun; Luo, Huimin; Dai, Sheng

    2013-11-19

    The invention is directed to a method for producing titanium dioxide nanotubes, the method comprising anodizing titanium metal in contact with an electrolytic medium containing an ionic liquid. The invention is also directed to the resulting titanium dioxide nanotubes, as well as devices incorporating the nanotubes, such as photovoltaic devices, hydrogen generation devices, and hydrogen detection devices.

  11. A SYNTHESIS METHOD OF BASIC TERNARY BENT-SQUARES BASED ON THE TRIAD SHIFT OPERATOR

    Directory of Open Access Journals (Sweden)

    O. N. Zhdanov

    2017-01-01

    Full Text Available Practical application of advanced algebraic constructions in modern communication systems based on MC-CDMA (Multi Code Code Division Multiple Access technology and in cryptography necessitates their further research. One of the most commonly used advanced algebraic construction is the binary bent-function having a uniform amplitude spectrum of the Walsh-Hadamard transform and, accordingly, having the maximal distance from the codewords of affine code. In addition to the binary bent-functions researchers are currently focuses on the development of synthesis methods of their many-valued analogues. In particular, one of the most effective methods for the synthesis of many-valued bent-functions is the method based on the Agievich bent-squares. In this paper, we developed a regular synthesis method of the ternary bent-squares on the basis of an arbitrary spectral vector and the regular operator of the triad shift. The classification of spectral vectors of lengths N = 3 and N = 9 is performed. On the basis of spectral classification more precise definition of many-valued bent-sequences is given, taking into account the existence of the phenomenon of many-valued bent-sequences for the length, determined by odd power of base. The paper results are valuable for practical use: the development of new constant amplitude codes for MC-CDMA technology, cryptographic primitives, data compression algorithms, signal structures, algorithms of block and stream encryption, based on advanced principles of many-valued logic. The developed bent-squares design method is also a basis for further theoretical research: development of methods of the permutation of rows and columns of basic bent-squares and their sign coding, synthesis of composite bent-squares. In addition, the data on the spectral classification of vectors give the task of constructing the synthesis methods of bent-functions of lengths N = 32k+1, k Є ℕ.

  12. Synthesis of Supported Bimetal Catalysts using Galvanic Deposition Method.

    Science.gov (United States)

    Mahara, Yuji; Ohyama, Junya; Sawabe, Kyoichi; Satsuma, Atsushi

    2018-02-22

    Supported bimetallic catalysts have been studied because of their enhanced catalytic properties due to metal-metal interactions compared with monometallic catalysts. We focused on galvanic deposition (GD) as a bimetallization method, which achieves well-defined metal-metal interfaces by exchanging heterogeneous metals with different ionisation tendencies. We have developed Ni@Ag/SiO 2 catalysts for CO oxidation, Co@Ru/Al 2 O 3 catalysts for automotive three-way reactions and Pd-Co/Al 2 O 3 catalysts for methane combustion by using the GD method. In all cases, the catalysts prepared by the GD method showed higher catalytic activity than the corresponding monometallic and bimetallic catalysts prepared by the conventional co-impregnation method. The GD method provides contact between noble and base metals to improve the electronic state, surface structure and reducibility of noble metals. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. The Robust Control Mixer Method for Reconfigurable Control Design By Using Model Matching Strategy

    DEFF Research Database (Denmark)

    Yang, Z.; Blanke, Mogens; Verhagen, M.

    2001-01-01

    This paper proposes a robust reconfigurable control synthesis method based on the combination of the control mixer method and robust H1 con- trol techniques through the model-matching strategy. The control mixer modules are extended from the conventional matrix-form into the LTI sys- tem form. By...... of one space robot arm system subjected to failures....

  14. Model correction factor method for system analysis

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager; Johannesen, Johannes M.

    2000-01-01

    The Model Correction Factor Method is an intelligent response surface method based on simplifiedmodeling. MCFM is aimed for reliability analysis in case of a limit state defined by an elaborate model. Herein it isdemonstrated that the method is applicable for elaborate limit state surfaces on which...... severallocally most central points exist without there being a simple geometric definition of the corresponding failuremodes such as is the case for collapse mechanisms in rigid plastic hinge models for frame structures. Taking as simplifiedidealized model a model of similarity with the elaborate model...... surface than existing in the idealized model....

  15. What is the most appropriate knowledge synthesis method to conduct a review? Protocol for a scoping review

    Directory of Open Access Journals (Sweden)

    Kastner Monika

    2012-08-01

    Full Text Available Abstract Background A knowledge synthesis attempts to summarize all pertinent studies on a specific question, can improve the understanding of inconsistencies in diverse evidence, and can identify gaps in research evidence to define future research agendas. Knowledge synthesis activities in healthcare have largely focused on systematic reviews of interventions. However, a wider range of synthesis methods has emerged in the last decade addressing different types of questions (e.g., realist synthesis to explore mediating mechanisms and moderators of interventions. Many different knowledge synthesis methods exist in the literature across multiple disciplines, but locating these, particularly for qualitative research, present challenges. There is a need for a comprehensive manual for synthesis methods (quantitative/qualitative or mixed, outlining how these methods are related, and how to match the most appropriate knowledge synthesis method to answer a research question. The objectives of this scoping review are to: 1 conduct a systematic search of the literature for knowledge synthesis methods across multi-disciplinary fields; 2 compare and contrast the different knowledge synthesis methods; and, 3 map out the specific steps to conducting the knowledge syntheses to inform the development of a knowledge synthesis methods manual/tool. Methods We will search relevant electronic databases (e.g., MEDLINE, CINAHL, grey literature, and discipline-based listservs. The scoping review will consider all study designs including qualitative and quantitative methodologies (excluding economic analysis or clinical practice guideline development, and identify knowledge synthesis methods across the disciplines of health, education, sociology, and philosophy. Two reviewers will pilot-test the screening criteria and data abstraction forms, and will independently screen the literature and abstract the data. A three-step synthesis process will be used to map the

  16. Development of Methods for the Hot Synthesis of S35-Labelled Biologically Active Substances

    International Nuclear Information System (INIS)

    Dzantiev, B.G.; Shishkov, A.V.

    1965-01-01

    It was found in investigations with model systems that sulphur-35 recoil atoms are capable of entering atom and atom-group substitution reactions through interaction with cyclic and heterocyclic compounds, as well as by way of the C-C bond. We therefore considered that it would be interesting to use the specific properties of hot sulphur atoms for the synthesis of labelled biologically active compounds. We selected 4-methyl-5β-hydroxyethyl thiazole (an intermediate product of vitamin B 1 synthesis), triethylenimine thiophosphoramide and amino acids (methionine, norvaline and norleucine) for investigation. Binary systems containing the compounds enumerated above, as well as CCI 4 or HCl (donors of hot S 35 atoms) were investigated. Irradiation was carried out in an IRT-1000 reactor channel at a thermal neutron flux of 10 11 -10 12 n/cm 2 * s. The S 35 recoil atoms, formed by the reaction Cl 35 (n, p) S 35 with a recoil energy of 16 keV, interact with the thiazole giving thiazole-S 35 . The yield of labelled product is highly dependent on the composition of the system, reaching a maximum of 20-25%. The addition of benzene (acceptor of the excitation energy) increases the yield of product, the maximum yield being reached when the ratio of CCl 4 , thiazole and benzene is 1:1:1. When the mixture of triethylenimine thiophosphoramide and CCl 4 is irradiated, an initial product labelled with S 35 and P 32 is obtained, the P 32 being formed by the reactions Cl 35 (n, α)P 32 , S 32 and P 31 (n, γ)P 32 . Methionine-S 35 is obtained by irradiating methionine and HCl in an aqueous solution. The labelled product formed is usually diluted by a carrier, although it is possible to obtain compounds without a carrier by selecting the initial compounds appropriately. Thus, by irradiating systems of norvaline-HCl and norleucine-HCl one obtains methionine-S 35 without a carrier, due to the entry of S 35 by way of the C-C bond into the norvaline molecule or the substitution of the CH

  17. Are paleoclimate model ensembles consistent with the MARGO data synthesis?

    Directory of Open Access Journals (Sweden)

    J. C. Hargreaves

    2011-08-01

    Full Text Available We investigate the consistency of various ensembles of climate model simulations with the Multiproxy Approach for the Reconstruction of the Glacial Ocean Surface (MARGO sea surface temperature data synthesis. We discover that while two multi-model ensembles, created through the Paleoclimate Model Intercomparison Projects (PMIP and PMIP2, pass our simple tests of reliability, an ensemble based on parameter variation in a single model does not perform so well. We show that accounting for observational uncertainty in the MARGO database is of prime importance for correctly evaluating the ensembles. Perhaps surprisingly, the inclusion of a coupled dynamical ocean (compared to the use of a slab ocean does not appear to cause a wider spread in the sea surface temperature anomalies, but rather causes systematic changes with more heat transported north in the Atlantic. There is weak evidence that the sea surface temperature data may be more consistent with meridional overturning in the North Atlantic being similar for the LGM and the present day. However, the small size of the PMIP2 ensemble prevents any statistically significant results from being obtained.

  18. A simple enzymic method for the synthesis of [32P]phosphoenolpyruvate

    International Nuclear Information System (INIS)

    Parra, F.

    1982-01-01

    A rapid and simple enzymic method is described for the synthesis of [ 32 P]phosphoenolpyruvate from [ 32 P]Psub(i), with a reproducible yield of 74%. The final product was shown to be a good substrate for pyruvate kinase (EC 2.7.1.40). (author)

  19. 2005 Nobel Prize in Chemistry: Development of the Olefin Metathesis Method in Organic Synthesis

    Science.gov (United States)

    Casey, Charles P.

    2006-01-01

    The 2005 Nobel Prize in Chemistry was awarded "for the development of the metathesis method in organic synthesis". The discoveries of the laureates provided a chemical reaction used daily in the chemical industry for the efficient and more environmentally friendly production of important pharmaceuticals, fuels, synthetic fibers, and many other…

  20. Large pyramid shaped single crystals of BiFeO{sub 3} by solvothermal synthesis method

    Energy Technology Data Exchange (ETDEWEB)

    Sornadurai, D.; Ravindran, T. R.; Paul, V. Thomas; Sastry, V. Sankara [Condensed Matter Physics Division, Materials Science Group, Physical Metallurgy Division, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India); Condensed Matter Physics Division, Materials Science Group (India)

    2012-06-05

    Synthesis parameters are optimized in order to grow single crystals of multiferroic BiFeO{sub 3}. 2 to 3 mm size pyramid (tetrahedron) shaped single crystals were successfully obtained by solvothermal method. Scanning electron microscopy with EDAX confirmed the phase formation. Raman scattering spectra of bulk BiFeO3 single crystals have been measured which match well with reported spectra.

  1. Process Synthesis, Design and Analysis using Process-Group Contribution Method

    DEFF Research Database (Denmark)

    Kumar Tula, Anjan; Eden, Mario Richard; Gani, Rafiqul

    Process synthesis implies the investigation of chemical reactions needed to produce the desired product, selection of the separation tec hniques needed for downstream processing, as well as making decisions on sequencing the involved reaction and separation operations. This work highlights the de...... methods [2] with mathematical programming techniques [3] to formulate and solve a superstructure based optimization problem....

  2. A Method of Timbre-Shape Synthesis Based On Summation of Spherical Curves

    DEFF Research Database (Denmark)

    Putnam, Lance Jonathan

    2014-01-01

    for simultaneous production of sonic tones and graphical curves based on additive synthesis of spherical curves. The spherical curves are generated from a sequence of elemental 3D rotations, similar to a Euler rotation. We show that this method can produce many important two- and three-dimensional curves directly...

  3. Synthesis of H2SO4 doped polyaniline film by potentiometric method

    Indian Academy of Sciences (India)

    Unknown

    Synthesis of H2SO4 doped polyaniline film by potentiometric method. P D GAIKWAD, D J SHIRALE, V K GADE, ... transition from insulator to semiconductor when doped with oxidizing or reducing agent (Kobayashi et ... protonation (doping) and many other physical–chemical properties are connected to the presence of ...

  4. Carbon nanotube synthesis via the catalytic CVD method: a review on the effect of reaction parameters

    OpenAIRE

    Öncel, Çınar; Oncel, Cinar; Yürüm, Yuda; Yurum, Yuda

    2006-01-01

    This review covers the results obtained in carbon nanotube synthesis by chemical vapor deposition. Parameters such as catalysts, supports, carbon precursors, reaction time, temperature and gas flow rates that are used in the production of carbon nanotubes are discussed throughout the text. Purification of the synthesized carbon nanotubes and methods utilized for cost reduction were also explored.

  5. Synthesis of large CZTSe nanoparticles through a two-step hot-injection method

    DEFF Research Database (Denmark)

    Engberg, Sara Lena Josefin; Li, Zhenggang; Lek, Jun Yan

    2015-01-01

    Grain boundaries in Cu2ZnSn(SxSe1x)4 (CZTSSe) thin films act as a defect that reduces the mobility of the charges. Hence one way to improve the performance of these thin film solar cells is to increase the grain size in the films. Most of the synthesis methods published so far for CZTSSe colloidal...

  6. A green and efficient method for the synthesis of homodimeric (β ...

    African Journals Online (AJOL)

    ... derivatives by intramolecular cyclization in various yields. Of particular interest is the use of the water as solvent of reaction and in absence of catalyst. Also these operating conditions protect the environment and economic points of view. Keywords: aqueous synthesis; bioactivity; dihydropyridine; dimedone; green method; ...

  7. Synthesis of carbon nanotube using camphor with SS 316 as catalytic substrate via oxidative heat treatment preparation method

    Science.gov (United States)

    Wulan, Praswasti Pembangun Dyah Kencana; Angelina, Dian

    2017-11-01

    Carbon nanotube (CNT) is a material that now often become the topic in nanotechnology research. CNT is widely used in the electronics industry especially for TV and computer flat panel displays, devices, automotives for car components, and batteries. Also for defense industries as well as other industries such as sports equipment. Camphor (C10H16O), a botanical hydrocarbon, can be used as a renewable and low cost carbon source for CNT synthesis. Synthesis was performed with stainless steel-316 (SS 316) as substrate, argon as carrier gas, and hydrogen as co-reactant. Preparation of the SS 316 was through a pretreatment by oxidative heat treatment method at a temperature of 850oC for 30 minutes, to remove the layer of chrome and make a rough surface as a growth media for CNT. The operating temperature of the synthesis used was 800oC with a reaction time of 60 minutes. Reactor, which made from stainless steel 316 (SS 316), was used for synthesis CNTs with maximum camphor mass of 20 grams. This research was conducted by varying the number of camphor mass by 5, 7, 10, 12, and 15 grams. The results showed that camphor decomposed into three compounds which are 40% benzene, 8% toluene, and 52% xylene. CNT grows on the surface of the SS 316 plate for each variation. CNTs have grown by follow tips growth model with deformations like buckling growth model and continuous growth model were also founded. The results of XRD showed that CNT were found in every camphor mass variation with high intensity at 2θ angle of 26° and 43°. The best quality and yield of CNT was obtained at camphor mass of 15 grams with carbon percentage of 87,1% and diameter 33 - 44 nm.

  8. Synthesis of micro- and nanodiamonds by the method of oxy- acetylene combustion flame

    International Nuclear Information System (INIS)

    Sabitov, S; Medyanova, B; Partizan, G; Koshanova, A; Mansurova, M; Lesbayev, B; Mansurov, B; Merkibayev, Ye

    2016-01-01

    This work presents the results of experiments on synthesis of micro- and nanodiamonds by the method of oxy-acetylene torch on the surface of pre-deposited copper thin films. The influence of the thickness of the buffer copper film and the concentration ratio of oxygen and acetylene on the structure formation of the deposited samples was investigated during performed experiments. Studies by Raman scattering and scanning electron microscopy showed that the synthesis of micro- and nano-diamonds occurs under certain experimental conditions. (paper)

  9. Modelling Method of Recursive Entity

    Science.gov (United States)

    Amal, Rifai; Messoussi, Rochdi

    2012-01-01

    With the development of the Information and Communication Technologies, great masses of information are published in the Web. In order to reuse, to share and to organise them in distance formation and e-learning frameworks, several research projects have been achieved and various standards and modelling languages developed. In our previous…

  10. Optimization of a surfactant free polyol method for the synthesis of platinum-cobalt electrocatalysts using Taguchi design of experiments

    Energy Technology Data Exchange (ETDEWEB)

    Grolleau, C. [Laboratoire de Catalyse en Chimie Organique (LACCO), Universite de Poitiers, 40 av Recteur Pineau, F-86000 Poitiers (France); ST Microelectronics Tours, rue Pierre et Marie Curie, F-37100 Tours (France); Coutanceau, C.; Leger, J.-M. [Laboratoire de Catalyse en Chimie Organique (LACCO), Universite de Poitiers, 40 av Recteur Pineau, F-86000 Poitiers (France); Pierre, F. [ST Microelectronics Tours, rue Pierre et Marie Curie, F-37100 Tours (France)

    2010-03-15

    A design of experiments (derived from the Taguchi method) was implemented to optimize experimental conditions of a surfactant free polyol method for the synthesis of PtCo electrocatalysts. Considered responses were the active surface area and the catalytic activity toward oxygen reduction reaction. Metallic salt concentration, pH, temperature ramp, addition order of reactants and particle cleaning step were chosen as main parameters according to considerations coming from literature and previous experiments. Matrix models describing the behaviour of the synthesis system was elaborated taking into account the effects of each considered parameter and their interactions. From this model, an optimized PtCo/C catalyst, in terms of active surface area and activity towards the oxygen reduction reaction, was synthesized. Both the measured values of the active surface area and the electrocatalytic activity are in very good agreement with the calculated ones from the matrix model. Furthermore, actions of parameters and interactions between parameters can be better understood using this method. (author)

  11. Solid-phase synthesis of polynucleotides. III. Synthesis of polynucleotides with defined sequences by the block coupling phosphotriester method.

    OpenAIRE

    Miyoshi, K; Huang, T; Itakura, K

    1980-01-01

    Preparation of the three hexadecanucleotides, dGpTpApTpCpApCpGpApGpGpCpCpCpTpT, dCpGpApCpGpApGpCpGpTpGpApCpApCpC and cTpGpCpCpGpGpCpCpApCpGpApTpGpCpG, is described by a rapid and simple solid-phase method on polyacrylamide supports. The synthesis were performed by the extension of the method described in the previous paper using di and trinucleotides of defined sequences as an incoming 3'-phosphodiester unit. Although the coupling yields to form phosphotriester bonds are slightly lower than t...

  12. Synthesis of research on Biogrout soil improvement method

    Directory of Open Access Journals (Sweden)

    Zsolt KALTENBACHER

    2014-12-01

    Full Text Available Because of the great rhythm of city developments, there is a great need for a new cost effective method for ground improvement. In this paper, a few chemical improvement technologies and a new biological ground improvement method called Biogrout are discussed. The method, used in the paper for a Sarmatian sand in Transylvania (Feleac locality implies using microorganisms as catalysts in order to induce a microbial carbonate precipitation (MICP to increase the strength and stiffness of cohesionless soils. For this calcium based procedure, the bacteria Sporosarcina Pasteurii (DSMZ 33 is used, while for the treatment solution urea (CO(NH22 and calcium chloride (CaCl2 are used. The study presents the triaxial testing of sand probes treated with Biogrout and the comparison of results obtained with untreated sand probes.

  13. Methods for the synthesis of deuterated vinyl pyridine monomers

    Science.gov (United States)

    Hong, Kunlun; Yang, Jun; Bonnesen, Peter V

    2014-02-25

    Methods for synthesizing deuterated vinylpyridine compounds of the Formula (1), wherein the method includes: (i) deuterating an acyl pyridine of the Formula (2) in the presence of a metal catalyst and D.sub.2O, wherein the metal catalyst is active for hydrogen exchange in water, to produce a deuterated acyl compound of Formula (3); (ii) reducing the compound of Formula (3) with a deuterated reducing agent to convert the acyl group to an alcohol group, and (iii) dehydrating the compound produced in step (ii) with a dehydrating agent to afford the vinylpyridine compound of Formula (1). The resulting deuterated vinylpyridine compounds are also described.

  14. Dynamic Model of an Ammonia Synthesis Reactor Based on Open Information

    OpenAIRE

    Jinasena, Asanthi; Lie, Bernt; Glemmestad, Bjørn

    2016-01-01

    Ammonia is a widely used chemical, hence the ammonia manufacturing process has become a standard case study in the scientific community. In the field of mathematical modeling of the dynamics of ammonia synthesis reactors, there is a lack of complete and well documented models. Therefore, the main aim of this work is to develop a complete and well documented mathematical model for observing the dynamic behavior of an industrial ammonia synthesis reactor system. The model is complete enough to ...

  15. Synthesis and Characterization of Colloidal CZTS Nanocrystals by a Hot-Injection Method

    Directory of Open Access Journals (Sweden)

    A. Méndez-López

    2016-01-01

    Full Text Available The present study reports the synthesis of colloidal Cu2ZnSnS4 (CZTS nanocrystals (average size ~4–9 nm by a simple and low cost hot-injection method. These nanocrystals form larger particles with sizes around 40 nm. Oleylamine (OLA was used as both the solvent and the nanocrystal stabilizer. The effect of the synthesis time on the structural, compositional, morphological, and optical properties was studied. As revealed by XRD, Raman, and TEM measurements all the prepared samples are comprised of both kesterite and wurtzite CZTS nanocrystals. The wurtzite phase contribution reduces as the reaction time is increased. The “bandgap” of the obtained nanoparticles tends to 1.52 eV for the larger synthesis times (24 h which is suitable for an absorber layer in thin films solar cells.

  16. Synthesis of carbon nanowall by plasma-enhanced chemical vapor deposition method.

    Science.gov (United States)

    Liu, Rulin; Chi, Yaqing; Fang, Liang; Tang, Zhensen; Yi, Xun

    2014-02-01

    Plasma-enhanced chemical vapor deposition (PECVD) is widely used for the synthesis of carbon materials, such as diamond-like carbons (DLCs), carbon nanotubes (CNTs) and carbon nanowalls (CNWs). Advantages of PECVD are low synthesis temperature compared with thermal CVD and the ability to grow vertically, free-standing structures. Due to its self-supported property and high specific surface area, CNWs are a promising material for field emission devices and other chemical applications. This article reviews the recent process on the synthesis of CNW by the PECVD method. We briefly introduce the structure and properties of CNW with characterization techniques. Growth mechanism is also discussed to analyze the influence of plasma conditions, substrates, temperature, and other parameters to the final film, which will give a suggestion on parameter modulation for desired film.

  17. Large-scale synthesis of YSZ nanopowder by Pechini method

    Indian Academy of Sciences (India)

    Administrator

    structure and chemical purity of 99⋅1% by inductively coupled plasma optical emission spectroscopy on a large scale. Keywords. Sol–gel; yttria-stabilized zirconia; large scale; nanopowder; Pechini method. 1. Introduction. Zirconia has attracted the attention of many scientists because of its tremendous thermal, mechanical ...

  18. Synthesis of methods to assess farms' sustainability | Mhamdi ...

    African Journals Online (AJOL)

    Sustainability in agriculture is attached to broader exits of the total economy. The main aims of this review paper are: (1) formulate definitions of sustainable development, (2) identify and know the components and the aspects of sustainability at the farm level, and (3) mention methods of sustainability's evaluation. Keywords: ...

  19. Modified Methods for the Synthesis of Triazinyl Fluorescent Brightener Intermediates

    Directory of Open Access Journals (Sweden)

    Ali Parach

    2003-03-01

    Full Text Available The production of triazinyl fluorescent brightener intermediates in high yields is described. The method involves a simplified work-up for the preparation of 4-nitro-toluene-2-sulfonic acid and the use of diethylene glycol instead of water in the preparation of 4,4'-dinitrostilbene-2,2'-disulfonic acid.

  20. Modeling methodology for supply chain synthesis and disruption analysis

    Science.gov (United States)

    Wu, Teresa; Blackhurst, Jennifer

    2004-11-01

    The concept of an integrated or synthesized supply chain is a strategy for managing today's globalized and customer driven supply chains in order to better meet customer demands. Synthesizing individual entities into an integrated supply chain can be a challenging task due to a variety of factors including conflicting objectives, mismatched incentives and constraints of the individual entities. Furthermore, understanding the effects of disruptions occurring at any point in the system is difficult when working toward synthesizing supply chain operations. Therefore, the goal of this research is to present a modeling methodology to manage the synthesis of a supply chain by linking hierarchical levels of the system and to model and analyze disruptions in the integrated supply chain. The contribution of this research is threefold: (1) supply chain systems can be modeled hierarchically (2) the performance of synthesized supply chain system can be evaluated quantitatively (3) reachability analysis is used to evaluate the system performance and verify whether a specific state is reachable, allowing the user to understand the extent of effects of a disruption.

  1. Domestication as a model system for the extended evolutionary synthesis.

    Science.gov (United States)

    Zeder, Melinda A

    2017-10-06

    One of the challenges in evaluating arguments for extending the conceptual framework of evolutionary biology involves the identification of a tractable model system that allows for an assessment of the core assumptions of the extended evolutionary synthesis (EES). The domestication of plants and animals by humans provides one such case study opportunity. Here, I consider domestication as a model system for exploring major tenets of the EES. First I discuss the novel insights that niche construction theory (NCT, one of the pillars of the EES) provides into the domestication processes, particularly as they relate to five key areas: coevolution, evolvability, ecological inheritance, cooperation and the pace of evolutionary change. This discussion is next used to frame testable predictions about initial domestication of plants and animals that contrast with those grounded in standard evolutionary theory, demonstrating how these predictions might be tested in multiple regions where initial domestication took place. I then turn to a broader consideration of how domestication provides a model case study consideration of the different ways in which the core assumptions of the EES strengthen and expand our understanding of evolution, including reciprocal causation, developmental processes as drivers of evolutionary change, inclusive inheritance, and the tempo and rate of evolutionary change.

  2. Effect of synthesis method on the preparation of lanthanum chromite for using as ceramic pigment

    International Nuclear Information System (INIS)

    Dantas, G.C.B.; Ferreira, K.M.B.; Pimentel, P.M.; Melo, D.M.A.; Gomes, D.K.S.; Costa, A.F.

    2016-01-01

    In this paper, LaCrO3 perovskites were synthesized by two synthesis methods, in order to compare these methods in function of microstructure and optical properties. The synthesis routes employed were a method that use gelatin as organic precursor and microwave assisted auto-combustion. The resulting powders were calcined at 800 ° C and 1000 ° C for obtaining the perovskite phase. Then, they were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM); UV-Visible spectroscopy and colorimetric analysis for color identification. No significant changes were observed in the powders synthesized by two routes. The oxides presented orthorhombic perovskite structure. The powders synthesized by the gelatin method were single phase. Chromite lanthanide presented grayish hue being darker in perovskites calcined at higher temperatures. (author)

  3. Synthesis of polyaniline nanotubes through UV light catalytic method

    Directory of Open Access Journals (Sweden)

    Chuanyu Sun

    2015-03-01

    Full Text Available In this study, nitrocellulose (NC fiber blanket prepared by electrostatic spinning method has been used as a template, and copper nitrate (Cu(NO32 as an oxidant to synthesise polyaniline nanotubes doped with heteropolyacid (H4SiW12O40, SiW12 using UV light catalytic method. Infrared spectroscopy (IR, X-ray powder diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM technologies were applied to characterize the prepared samples of polyaniline nanotubes. The results show that the external diameter of the tube is about 200 nm, and the internal diameter about 170 nm. We also give a reasonable speculation and explanation about the formation mechanism of the nanotubes.

  4. Low-Energy, Hydrogen-Free Method of Diamond Synthesis

    Science.gov (United States)

    Varshney, Deepak (Inventor); Morell, Gerardo (Inventor); Weiner, Brad R. (Inventor); Makarov, Vladimir (Inventor)

    2013-01-01

    Diamond thin films were deposited on copper substrate by the Vapor Solid (VS) deposition method using a mixture of fullerene C(sub 60) and graphite as the source material. The deposition took place only when the substrate was kept in a narrow temperature range of approximately 550-650 C. Temperatures below and above this range results in the deposition of fullerenes and other carbon compounds, respectively.

  5. An Efficient Method for the N-Bromosuccinimide Catalyzed Synthesis of Indolyl-Nitroalkanes

    Directory of Open Access Journals (Sweden)

    Ching-Fa Yao

    2009-10-01

    Full Text Available An efficient and practical method for the synthesis of indolyl-nitroalkane derivatives catalyzed by N-bromosuccinimide is described. The generality of this method was demonstrated by synthesizing an array of diverse 3-substituted indole derivatives by the reaction of different β-nitrostyrenes with various substituted indoles. Simple reaction conditions accompanied by good yields of indolyl-nitroalkanes are the merits of this methodology.

  6. Developing a TQM quality management method model

    OpenAIRE

    Zhang, Zhihai

    1997-01-01

    From an extensive review of total quality management literature, the external and internal environment affecting an organization's quality performance and the eleven primary elements of TQM are identified. Based on the primary TQM elements, a TQM quality management method model is developed. This model describes the primary quality management methods which may be used to assess an organization's present strengths and weaknesses with regard to its use of quality management methods. This model ...

  7. Synthesis of nitrogen-doped graphene via solid microwave method

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Li, E-mail: zhangli379@sohu.com [School of Electrical Engineering, Dalian University of Technology, Dalian, Liaoning 116024 (China); Ji, Bingcheng, E-mail: debbo.jee@outlook.com [School of Electrical Engineering, Dalian University of Technology, Dalian, Liaoning 116024 (China); Wang, Kai [School of Electrical Engineering, Dalian University of Technology, Dalian, Liaoning 116024 (China); Song, Jinyan [School of Information Engineering, Dalian Ocean University, Dalian, Liaoning 116024 (China)

    2014-07-01

    Graphical abstract: - Highlights: • A direct solid microwave method is developed to prepare nitrogen-doped graphene. • The method consists of two steps, namely the functionalization and microwave irradiation. • Melamine can serve as not only functionalizing agent but also nitrogen source. - Abstract: In this paper, we propose a solid microwave-mediated method for scalable production of nitrogen-doped graphene sheets (NGS) using low-cost industrial material melamine as functionalizing agent and nitrogen source. The strong interaction of microwaves with graphene oxide has been fully utilized to generate in situ heating that induces the decompose melamine and nitrogen doping of graphene. The morphology, structure, and components of the as-produced nitrogen-doped graphene are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), pore-size distribution (PSD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectra (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The results show NGS can be successfully synthesized via this strategy.

  8. Higuchi’s Method applied to detection of changes in timbre of digital sound synthesis of string instruments with the functional transformation method

    Science.gov (United States)

    Kanjanapen, Manorth; Kunsombat, Cherdsak; Chiangga, Surasak

    2017-09-01

    The functional transformation method (FTM) is a powerful tool for detailed investigation of digital sound synthesis by the physical modeling method, the resulting sound or measured vibrational characteristics at discretized points on real instruments directly solves the underlying physical effect of partial differential equation (PDE). In this paper, we present the Higuchi’s method to examine the difference between the timbre of tone and estimate fractal dimension of musical signals which contains information about their geometrical structure that synthesizes by FTM. With the Higuchi’s method we obtain the whole process is not complicated, fast processing, with the ease of analysis without expertise in the physics or virtuoso musicians and the easiest way for the common people can judge that sounds similarly presented.

  9. Spectral methods applied to Ising models

    International Nuclear Information System (INIS)

    DeFacio, B.; Hammer, C.L.; Shrauner, J.E.

    1980-01-01

    Several applications of Ising models are reviewed. A 2-d Ising model is studied, and the problem of describing an interface boundary in a 2-d Ising model is addressed. Spectral methods are used to formulate a soluble model for the surface tension of a many-Fermion system

  10. Sensitivity Analysis of Power Distribution Synthesis Method for Failed In core Detector

    International Nuclear Information System (INIS)

    Koo, Bonseung; Cho, Jinyoung; Kim, Kyoyoun

    2013-01-01

    In this paper, performance of RCOMS 3-D power distribution synthesis method is evaluated and sensitivity analysis for the number of failed detector is tested. The performance of a 3-dimensional power distribution synthesis method (DPCM3D) was evaluated for the digital core monitoring system (RCOMS). RCOMS shows negligible power distribution errors and less sensitive to the number of available detectors compared with COLSS. By employing a DPCM3D method in RCOMS, it is judged that a core power distribution could be synthesized more accurately by eliminating the fitting error with a minimum available detector numbers and it would lead to thermal margin increase. A 3-dimensional power distribution synthesis method (called DPCM3D) has been developed by KAERI. RCOMS(Real-time calculator for COre Monitoring System) adopts the method instead of Fourier expansion method being used in COLSS of conventional PWRs. COLSS generates level-averaged detector responses from in core detector signals and fits core average axial power shape. Thus, COLSS inevitably includes considerable fitting error in itself. However, DPCM3D produces a synthetic 3-D power distribution by coupling a neutronics code and measured in core detector signals without any fitting

  11. A business case method for business models

    OpenAIRE

    Meertens, Lucas Onno; Starreveld, E.; Iacob, Maria Eugenia; Nieuwenhuis, Lambertus Johannes Maria; Shishkov, Boris

    2013-01-01

    Intuitively, business cases and business models are closely connected. However, a thorough literature review revealed no research on the combination of them. Besides that, little is written on the evaluation of business models at all. This makes it difficult to compare different business model alternatives and choose the best one. In this article, we develop a business case method to objectively compare business models. It is an eight-step method, starting with business drivers and ending wit...

  12. Residual-based model diagnosis methods for mixture cure models.

    Science.gov (United States)

    Peng, Yingwei; Taylor, Jeremy M G

    2017-06-01

    Model diagnosis, an important issue in statistical modeling, has not yet been addressed adequately for cure models. We focus on mixture cure models in this work and propose some residual-based methods to examine the fit of the mixture cure model, particularly the fit of the latency part of the mixture cure model. The new methods extend the classical residual-based methods to the mixture cure model. Numerical work shows that the proposed methods are capable of detecting lack-of-fit of a mixture cure model, particularly in the latency part, such as outliers, improper covariate functional form, or nonproportionality in hazards if the proportional hazards assumption is employed in the latency part. The methods are illustrated with two real data sets that were previously analyzed with mixture cure models. © 2016, The International Biometric Society.

  13. Exploring Several Methods of Groundwater Model Selection

    Science.gov (United States)

    Samani, Saeideh; Ye, Ming; Asghari Moghaddam, Asghar

    2017-04-01

    Selecting reliable models for simulating groundwater flow and solute transport is essential to groundwater resources management and protection. This work is to explore several model selection methods for avoiding over-complex and/or over-parameterized groundwater models. We consider six groundwater flow models with different numbers (6, 10, 10, 13, 13 and 15) of model parameters. These models represent alternative geological interpretations, recharge estimates, and boundary conditions at a study site in Iran. The models were developed with Model Muse, and calibrated against observations of hydraulic head using UCODE. Model selection was conducted by using the following four approaches: (1) Rank the models using their root mean square error (RMSE) obtained after UCODE-based model calibration, (2) Calculate model probability using GLUE method, (3) Evaluate model probability using model selection criteria (AIC, AICc, BIC, and KIC), and (4) Evaluate model weights using the Fuzzy Multi-Criteria-Decision-Making (MCDM) approach. MCDM is based on the fuzzy analytical hierarchy process (AHP) and fuzzy technique for order performance, which is to identify the ideal solution by a gradual expansion from the local to the global scale of model parameters. The KIC and MCDM methods are superior to other methods, as they consider not only the fit between observed and simulated data and the number of parameter, but also uncertainty in model parameters. Considering these factors can prevent from occurring over-complexity and over-parameterization, when selecting the appropriate groundwater flow models. These methods selected, as the best model, one with average complexity (10 parameters) and the best parameter estimation (model 3).

  14. Mechatronic Systems Design Methods, Models, Concepts

    CERN Document Server

    Janschek, Klaus

    2012-01-01

    In this textbook, fundamental methods for model-based design of mechatronic systems are presented in a systematic, comprehensive form. The method framework presented here comprises domain-neutral methods for modeling and performance analysis: multi-domain modeling (energy/port/signal-based), simulation (ODE/DAE/hybrid systems), robust control methods, stochastic dynamic analysis, and quantitative evaluation of designs using system budgets. The model framework is composed of analytical dynamic models for important physical and technical domains of realization of mechatronic functions, such as multibody dynamics, digital information processing and electromechanical transducers. Building on the modeling concept of a technology-independent generic mechatronic transducer, concrete formulations for electrostatic, piezoelectric, electromagnetic, and electrodynamic transducers are presented. More than 50 fully worked out design examples clearly illustrate these methods and concepts and enable independent study of th...

  15. Synthesis of Copper Nanoparticles Using a Different Method: Determination of Its Antioxidant and Antimicrobial Activity

    Directory of Open Access Journals (Sweden)

    Demet Demirci Gültekin

    2016-10-01

    Full Text Available In this study, it was aimed to obtain copper oxide nanoparticles (CuO NPs with the method of green synthesis by using peroxidase enzymes which were partly purified from fig (Ficus carica. Copper (II oxide nanoparticles are successfully synthesized with the green synthesis method on the experiments we performed.  UV-VIS spectroscopy of the characterization of acquired CuO NPs were performed with Scanning Electron Microscopy (SEM and X-ray Diffraction (XRD. Optimum activation temperature for green synthesis was observed to be in 30 min, pH:8, at 25 oC and in the concentration of 1mM CuCl2. By using peroxidase enzymes with green synthesis, it was found out the results of SEM and XRD measurements that acquired CuO NPs were in the size of 50-120 nm. Afterwards, the antioxidant and antibacterial activities of these nanoparticles were measured and it was understood from the obtained results that CuO NPs had both antioxidant and antimicrobial activities.

  16. Rapid synthesis of single-phase bismuth ferrite by microwave-assisted hydrothermal method

    International Nuclear Information System (INIS)

    Cao, Wenqian; Chen, Zhi; Gao, Tong; Zhou, Dantong; Leng, Xiaonan; Niu, Feng; Zhu, Yuxiang; Qin, Laishun; Wang, Jiangying; Huang, Yuexiang

    2016-01-01

    This paper describes on the fast synthesis of bismuth ferrite by the simple microwave-assisted hydrothermal method. The phase transformation and the preferred growth facets during the synthetic process have been investigated by X-ray diffraction. Bismuth ferrite can be quickly prepared by microwave hydrothermal method by simply controlling the reaction time, which is further confirmed by Fourier Transform infrared spectroscopy and magnetic measurement. - Graphical abstract: Single-phase BiFeO 3 could be realized at a shortest reaction time of 65 min. The reaction time has strong influences on the phase transformation and the preferred growth facets. - Highlights: • Rapid synthesis (65 min) of BiFeO 3 by microwave-assisted hydrothermal method. • Reaction time has influence on the purity and preferred growth facets. • FTIR and magnetic measurement further confirm the pure phase.

  17. Measuring serotonin synthesis: from conventional methods to PET tracers and their (pre)clinical implications

    Energy Technology Data Exchange (ETDEWEB)

    Visser, Anniek K.D.; Waarde, Aren van; Willemsen, Antoon T.M. [University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); Bosker, Fokko J. [University of Groningen, University Medical Center Groningen, University Center of Psychiatry, Groningen (Netherlands); Luiten, Paul G.M. [University of Groningen, Center for Behavior and Neurosciences, Department of Molecular Neurobiology, Haren (Netherlands); Boer, Johan A. den [University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); University of Groningen, University Medical Center Groningen, University Center of Psychiatry, Groningen (Netherlands); Kema, Ido P. [University of Groningen, University Medical Center Groningen, Department of Laboratory Medicine, Groningen (Netherlands); Dierckx, Rudi A.J.O. [University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); University Hospital Ghent, Department of Nuclear Medicine, Ghent (Belgium)

    2011-03-15

    The serotonergic system of the brain is complex, with an extensive innervation pattern covering all brain regions and endowed with at least 15 different receptors (each with their particular distribution patterns), specific reuptake mechanisms and synthetic processes. Many aspects of the functioning of the serotonergic system are still unclear, partially because of the difficulty of measuring physiological processes in the living brain. In this review we give an overview of the conventional methods of measuring serotonin synthesis and methods using positron emission tomography (PET) tracers, more specifically with respect to serotonergic function in affective disorders. Conventional methods are invasive and do not directly measure synthesis rates. Although they may give insight into turnover rates, a more direct measurement may be preferred. PET is a noninvasive technique which can trace metabolic processes, like serotonin synthesis. Tracers developed for this purpose are {alpha}-[{sup 11}C]methyltryptophan ([{sup 11}C]AMT) and 5-hydroxy-L-[{beta}-{sup 11}C]tryptophan ([{sup 11}C]5-HTP). Both tracers have advantages and disadvantages. [{sup 11}C]AMT can enter the kynurenine pathway under inflammatory conditions (and thus provide a false signal), but this tracer has been used in many studies leading to novel insights regarding antidepressant action. [{sup 11}C]5-HTP is difficult to produce, but trapping of this compound may better represent serotonin synthesis. AMT and 5-HTP kinetics are differently affected by tryptophan depletion and changes of mood. This may indicate that both tracers are associated with different enzymatic processes. In conclusion, PET with radiolabelled substrates for the serotonergic pathway is the only direct way to detect changes of serotonin synthesis in the living brain. (orig.)

  18. Synthesis and ultrastructure of plate-like apatite single crystals as a model for tooth enamel

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Zhi, E-mail: zhuang@meiji.ac.jp [Department of Applied Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Yoshimura, Hideyuki, E-mail: hyoshi@isc.meiji.ac.jp [Department of Physics, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan); Aizawa, Mamoru, E-mail: mamorua@isc.meiji.ac.jp [Department of Applied Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571 (Japan)

    2013-07-01

    Hydroxyapatite (HAp) is an inorganic constituent compound of human bones and teeth, with superior biocompatibility and bioactivity characteristics. Its crystal structure is hexagonal, characterized by a(b)- and c-planes. In vertebrate long bones, HAp crystals have a c-axis orientation, while in tooth enamel, they have an a(b)-axis orientation. Many methods can be used to synthesize c-axis oriented HAp single crystals; however, to the best of our knowledge, there have been no reports on a synthesis method for a(b)-axis oriented HAp single crystals. In this study, we successfully synthesized plate-like HAp crystals at the air–liquid interface of a starting solution via an enzyme reaction of urea with urease. Crystal phase analysis and ultrastructure observations were carried out, and the results indicated that the particles were single crystals, with almost the same a(b)-axis orientation as tooth enamel. It is hoped that by utilizing their unique surface charge and atomic arrangement, the resulting particles can be used as a high-performance biomaterial, capable of adsorbing bio-related substances and a model for tooth enamel. - Highlights: ► Synthesis of plate-like hydroxyapatite crystals at air–liquid interface ► Ultrastructural analysis of plate-like hydroxyapatite crystals ► Plate-like hydroxyapatite single crystals with a high a(b)-axis orientation ► Plate-like hydroxyapatite single crystals as a model for tooth enamel.

  19. P-B Desulfurization: An Enabling Method for Protein Chemical Synthesis and Site-Specific Deuteration.

    Science.gov (United States)

    Jin, Kang; Li, Tianlu; Chow, Hoi Yee; Liu, Han; Li, Xuechen

    2017-11-13

    Cysteine-mediated native chemical ligation is a powerful method for protein chemical synthesis. Herein, we report an unprecedentedly mild system (TCEP/NaBH 4 or TCEP/LiBEt 3 H; TCEP=tris(2-carboxyethyl)phosphine) for chemoselective peptide desulfurization to achieve effective protein synthesis via the native chemical ligation-desulfurization approach. This method, termed P-B desulfurization, features usage of common reagents, simplicity of operation, robustness, high yields, clean conversion, and versatile functionality compatibility with complex peptides/proteins. In addition, this method can be used for incorporating deuterium into the peptides after cysteine desulfurization by running the reaction in D 2 O buffer. Moreover, this method enables the clean desulfurization of peptides carrying post-translational modifications, such as phosphorylation and crotonylation. The effectiveness of this method has been demonstrated by the synthesis of the cyclic peptides dichotomin C and E and synthetic proteins, including ubiquitin, γ-synuclein, and histone H2A. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Thermoluminescence study of aluminium oxide doped germanium prepared by combustion synthesis method

    Directory of Open Access Journals (Sweden)

    Saharin Nurul Syazlin Binti

    2017-01-01

    Full Text Available The present paper reports the optimum concentration of germanium (Ge dopant in aluminium oxide (AhO3 samples prepared by combustion synthesis (CS method for thermoluminescence (TL studies. The samples were prepared at various Ge concentration i.e. 1 to 5% mol. The phase formation of un-doped and Ge-doped Al2O3 samples was determined using X-ray Diffraction (XRD. The sharp peaks present in the XRD pattern confirms the crystallinity of the samples. The samples were then exposed to 50 Gy Cobalt-60 sources (Gamma cell 220. TL glow curves were measured and recorded using a Harshaw Model 3500 TLD reader. Comparison of TL peaks were observed to obtain the best composition of Ge dopants. A simple glow curves TL peak at around 175̊C for all composition samples was observed. It was also found that the composition of aluminium oxide doped with 3.0% of germanium exhibits the highest thermoluminescence (TL intensity which is 349747.04 (a.u.

  1. Synthesis and Characterization of Hydroxyapatite Powder by Wet Precipitation Method

    Science.gov (United States)

    Cahyaningrum, S. E.; Herdyastuty, N.; Devina, B.; Supangat, D.

    2018-01-01

    Hydroxyapatite is main inorganic component of the bone with formula Ca10(PO4)6(OH)2. Hydroxyapatite can be used as substituted bone biomaterial because biocompatible, non toxic, and osteoconductive. In this study, hydroxyapatite is synthesized using wet precipitation method from egg shell. The product was sintered at different temperatures of 800°C to 1000°C to improve its crystallinity. The hydroxyapatite was characterized by X-ray analysis, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) to reveal its phase content, morphology and types of bond present within it. The analytical results showed hydroxyapatite had range in crystallinity from 85.527 to 98.753%. The analytical functional groups showed that presence of functional groups such as OH, (PO4)3 2‑, and CO3 2‑ that indicated as hydroxyapatite. The result of characterization SEM indicated that hydroxyapatite without sintering and HAp sintering at 800 °C were irregular shape without pore. The best hydroxyapatite with temperature sintering at 900 °C showed oval shaped with pores without agglomerated.

  2. The synthesis of hydroxyapatite through the precipitation method

    International Nuclear Information System (INIS)

    Shah Rizal, K.; Fahmi, M.N.; Mat Akil, H.; Zainal Arifin, A.

    2004-01-01

    Hydroxyapatite (HA) has been earmarked as suitable for implantation within the human body due to the similarity of its chemical makeup to human bone, In this paper, HA powders were synthesized via the precipitation method where phosphoric acid (H 3 PO 4 ) was titrated into calcium hydroxide solution [Ca(OH) 2 ]. Two parameters such as temperature and stirring rate were identified as factors that influenced the amount and purity of HA powder, Phase identification of the synthesized powder was done using X-Ray Diffraction (XRD). The results show that HA phase can be synthesized from this titration process of Ca(OH) 2 and H 3 PO 4 with yield amount of HA powder around 45-61 grams but with less than hundred percent purity. In order to study the effect of heat treatment to RA crystals structure, HA powder was calcined at 850 degree C for 2 hours. Its found that the degree of crystallinity increases after calcination because of lattice expansion when the materials were heated at higher temperature. (Author)

  3. The synthesis of hydroxyapatite through the precipitation method.

    Science.gov (United States)

    Shah, Rizal K; Fahmi, M N; Mat, Akil H; Zainal, Arifin A

    2004-05-01

    Hydroxyapatite (HA) has been earmarked as suitable for implantation within the human of its chemical makeup to human bone. In this paper, HA powders were synthesized via the precipitation method where phosphoric acid (H3PO4) was titrated into calcium hydroxide solution [Ca(OH)2]. Two parameters such as temperature and stirring rate were identified as factors that influenced the amount and purity of HA powder. Phase identification of the synthesized powder was done using X-Ray Diffraction (XRD). The results show that HA phase can be synthesized from this titration process of Ca(OH)2 and H3PO4 with yield amount of HA powder around 45 - 61 grams but with less than hundred percent purity. In order to study the effect of heat treatment to HA crystals structure, HA powder was calcined at 850 degrees C for 2 hours. It's found that the degree of crystallinity increases after calcination because of lattice expansion when the materials were heated at higher temperature

  4. Simple Models for Model-based Portfolio Load Balancing Controller Synthesis

    DEFF Research Database (Denmark)

    Edlund, Kristian Skjoldborg; Mølbak, Tommy; Bendtsen, Jan Dimon

    2010-01-01

    This paper presents a collection of models of so-called 'effectuators', i.e., subsystems in a power plant portfolio that represent control actions with associated dynamics and actuation costs. These models are derived in order to facilitate higher-level model-based control synthesis of a portfolio...... of generation units existing in an electrical power supply network, for instance in model-based predictive control or declarative control schemes. We focus on the effectuators found in the Danish power system. In particular, the paper presents models for boiler load, district heating, condensate throttling...... and wind turbine effectuators. Each model is validated against actual measurement data. Considering their simplicity, the models fit the observed data very well and are thus suitable for control purposes....

  5. Yunnan-III models for evolutionary population synthesis

    Science.gov (United States)

    Zhang, F.; Li, L.; Han, Z.; Zhuang, Y.; Kang, X.

    2013-02-01

    We build the Yunnan-III evolutionary population synthesis (EPS) models by using the mesa stellar evolution code, BaSeL stellar spectra library and the initial mass functions (IMFs) of Kroupa and Salpeter, and present colours and integrated spectral energy distributions (ISEDs) of solar-metallicity stellar populations (SPs) in the range of 1 Myr to 15 Gyr. The main characteristic of the Yunnan-III EPS models is the usage of a set of self-consistent solar-metallicity stellar evolutionary tracks (the masses of stars are from 0.1 to 100 M⊙). This set of tracks is obtained by using the state-of-the-art mesa code. mesa code can evolve stellar models through thermally pulsing asymptotic giant branch (TP-AGB) phase for low- and intermediate-mass stars. By comparisons, we confirm that the inclusion of TP-AGB stars makes the V - K, V - J and V - R colours of SPs redder and the infrared flux larger at ages log(t/yr) ≳ 7.6 [the differences reach the maximum at log(t/yr) ˜ 8.6, ˜0.5-0.2 mag for colours, approximately two times for K-band flux]. We also find that the colour-evolution trends of Model with-TPAGB at intermediate and large ages are similar to those from the starburst99 code, which employs the Padova-AGB stellar library, BaSeL spectral library and the Kroupa IMF. At last, we compare the colours with the other EPS models comprising TP-AGB stars (such as CB07, M05, V10 and POPSTAR), and find that the B - V colour agrees with each other but the V-K colour shows a larger discrepancy among these EPS models [˜1 mag when 8 ≲ log(t/yr) ≲ 9]. The stellar evolutionary tracks, isochrones, colours and ISEDs can be obtained on request from the first author or from our website (http://www1.ynao.ac.cn/~zhangfh/). Using the isochrones, you can build your EPS models. Now the format of stellar evolutionary tracks is the same as that in the starburst99 code; you can put them into the starburst99 code and get the SP's results. Moreover, the colours involving other passbands

  6. Surface Coating of Oxide Powders: A New Synthesis Method to Process Biomedical Grade Nano-Composites

    Directory of Open Access Journals (Sweden)

    Paola Palmero

    2014-07-01

    Full Text Available Composite and nanocomposite ceramics have achieved special interest in recent years when used for biomedical applications. They have demonstrated, in some cases, increased performance, reliability, and stability in vivo, with respect to pure monolithic ceramics. Current research aims at developing new compositions and architectures to further increase their properties. However, the ability to tailor the microstructure requires the careful control of all steps of manufacturing, from the synthesis of composite nanopowders, to their processing and sintering. This review aims at deepening understanding of the critical issues associated with the manufacturing of nanocomposite ceramics, focusing on the key role of the synthesis methods to develop homogeneous and tailored microstructures. In this frame, the authors have developed an innovative method, named “surface-coating process”, in which matrix oxide powders are coated with inorganic precursors of the second phase. The method is illustrated into two case studies; the former, on Zirconia Toughened Alumina (ZTA materials for orthopedic applications, and the latter, on Zirconia-based composites for dental implants, discussing the advances and the potential of the method, which can become a valuable alternative to the current synthesis process already used at a clinical and industrial scale.

  7. Guidance for deciding upon use of primary mixed methods studies in research synthesis : Lessons learned in childhood trauma

    NARCIS (Netherlands)

    Boeije, H.; van Wesel, F.; Slagt, M.

    2014-01-01

    When reviewing literature, mixed methods studies (MMS) are increasingly retrieved, yet it is unclear how they should be dealt with in a research synthesis. In this article we examine the inclusion of primary MMS in research synthesis, based on experiences with a meta-analysis (MA) and a qualitative

  8. Guidance for deciding upon use of primary mixed methods studies in research synthesis: lessons learned in childhood trauma

    NARCIS (Netherlands)

    Boeije, H.R.; van Wesel, F.; Slagt, M.I.

    2014-01-01

    When reviewing literature, mixed methods studies (MMS) are increasingly retrieved, yet it is unclear how they should be dealt with in a research synthesis. In this article we examine the inclusion of primary MMS in research synthesis, based on experiences with a meta-analysis (MA) and a qualitative

  9. Guidance for deciding upon use of primary mixed methods studies in research synthesis: lessons learned in childhood trauma.

    NARCIS (Netherlands)

    Boeije, H.; Wesel, F. van; Slagt, M.

    2014-01-01

    When reviewing literature, mixed methods studies (MMS) are increasingly retrieved, yet it is unclear how they should be dealt with in a research synthesis. In this article we examine the inclusion of primary MMS in research synthesis, based on experiences with a meta-analysis (MA) and a qualitative

  10. Twitter's tweet method modelling and simulation

    Science.gov (United States)

    Sarlis, Apostolos S.; Sakas, Damianos P.; Vlachos, D. S.

    2015-02-01

    This paper seeks to purpose the concept of Twitter marketing methods. The tools that Twitter provides are modelled and simulated using iThink in the context of a Twitter media-marketing agency. The paper has leveraged the system's dynamic paradigm to conduct Facebook marketing tools and methods modelling, using iThink™ system to implement them. It uses the design science research methodology for the proof of concept of the models and modelling processes. The following models have been developed for a twitter marketing agent/company and tested in real circumstances and with real numbers. These models were finalized through a number of revisions and iterators of the design, develop, simulate, test and evaluate. It also addresses these methods that suit most organized promotion through targeting, to the Twitter social media service. The validity and usefulness of these Twitter marketing methods models for the day-to-day decision making are authenticated by the management of the company organization. It implements system dynamics concepts of Twitter marketing methods modelling and produce models of various Twitter marketing situations. The Tweet method that Twitter provides can be adjusted, depending on the situation, in order to maximize the profit of the company/agent.

  11. Auralization of vibroacoustic models in engineering using Wave Field Synthesis: Application to plates and transmission loss

    Science.gov (United States)

    Bolduc, A.; Gauthier, P.-A.; Berry, A.

    2017-12-01

    While perceptual evaluation and sound quality testing with jury are now recognized as essential parts of acoustical product development, they are rarely implemented with spatial sound field reproduction. Instead, monophonic, stereophonic or binaural presentations are used. This paper investigates the workability and interest of a method to use complete vibroacoustic engineering models for auralization based on 2.5D Wave Field Synthesis (WFS). This method is proposed in order that spatial characteristics such as directivity patterns and direction-of-arrival are part of the reproduced sound field while preserving the model complete formulation that coherently combines frequency and spatial responses. Modifications to the standard 2.5D WFS operators are proposed for extended primary sources, affecting the reference line definition and compensating for out-of-plane elementary primary sources. Reported simulations and experiments of reproductions of two physically-accurate vibroacoustic models of thin plates show that the proposed method allows for an effective reproduction in the horizontal plane: Spatial and frequency domains features are recreated. Application of the method to the sound rendering of a virtual transmission loss measurement setup shows the potential of the method for use in virtual acoustical prototyping for jury testing.

  12. A Behavioral Handwriting Model for Static and Dynamic Signature Synthesis.

    Science.gov (United States)

    Ferrer, Miguel A; Diaz, Moises; Carmona-Duarte, Cristina; Morales, Aythami

    2017-06-01

    The synthetic generation of static handwritten signatures based on motor equivalence theory has been recently proposed for biometric applications. Motor equivalence divides the human handwriting action into an effector dependent cognitive level and an effector independent motor level. The first level has been suggested by others as an engram, generated through a spatial grid, and the second has been emulated with kinematic filters. Our paper proposes a development of this methodology in which we generate dynamic information and provide a unified comprehensive synthesizer for both static and dynamic signature synthesis. The dynamics are calculated by lognormal sampling of the 8-connected continuous signature trajectory, which includes, as a novelty, the pen-ups. The forgery generation imitates a signature by extracting the most perceptually relevant points of the given genuine signature and interpolating them. The capacity to synthesize both static and dynamic signatures using a unique model is evaluated according to its ability to adapt to the static and dynamic signature inter- and intra-personal variability. Our highly promising results suggest the possibility of using the synthesizer in different areas beyond the generation of unlimited databases for biometric training.

  13. Graphene-Reinforced Aluminum Matrix Composites: A Review of Synthesis Methods and Properties

    Science.gov (United States)

    Chen, Fei; Gupta, Nikhil; Behera, Rakesh K.; Rohatgi, Pradeep K.

    2018-03-01

    Graphene-reinforced aluminum (Gr-Al) matrix nanocomposites (NCs) have attracted strong interest from both research and industry in high-performance weight-sensitive applications. Due to the vastly different bonding characteristics of the Al matrix (metallic) and graphene (in-plane covalent + inter-plane van der Waals), the graphene phase has a general tendency to agglomerate and phase separate in the metal matrix, which is detrimental for the mechanical and chemical properties of the composite. Thus, synthesis of Gr-Al NCs is extremely challenging. This review summarizes the different methods available to synthesize Gr-Al NCs and the resulting properties achieved in these NCs. Understanding the effect of processing parameters on the realized properties opens up the possibility of tailoring the synthesis methods to achieve the desired properties for a given application.

  14. Chemical vs. biotechnological synthesis of C13-apocarotenoids: current methods, applications and perspectives.

    Science.gov (United States)

    Cataldo, Vicente F; López, Javiera; Cárcamo, Martín; Agosin, Eduardo

    2016-07-01

    Apocarotenoids are natural compounds derived from the oxidative cleavage of carotenoids. Particularly, C13-apocarotenoids are volatile compounds that contribute to the aromas of different flowers and fruits and are highly valued by the Flavor and Fragrance industry. So far, the chemical synthesis of these terpenoids has dominated the industry. Nonetheless, the increasing consumer demand for more natural and sustainable processes raises an interesting opportunity for bio-production alternatives. In this regard, enzymatic biocatalysis and metabolically engineered microorganisms emerge as attractive biotechnological options. The present review summarizes promising bioengineering approaches with regard to chemical production methods for the synthesis of two families of C13-apocarotenoids: ionones/dihydroionones and damascones/damascenone. We discuss each method and its applicability, with a thorough comparative analysis for ionones, focusing on the production process, regulatory aspects, and sustainability.

  15. Evaluation of biological activities of nanocrystalline zirconia synthesis via combustion method

    International Nuclear Information System (INIS)

    Thakare, V.G.; Omanwar, S.K.; Bhatkar, V.B.; Wadegaokar, P.A.

    2016-01-01

    The objective of the following study was synthesis of nanocrystalline zirconia by modified solution combustion synthesis method and evaluation of its structural and biological properties. The sample was characterized by powder X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and evaluated for cytotoxicity study using 3T3 mouse fibroblast cells, the antibacterial property are investigated by spread plate method against E. coli bacterial pathogen and studied for degradation using phosphate buffered saline (PBS) solution. The XRD pattern shows that the monoclinic phase of nanocrystalline zirconia was obtained. The FESEM images showed that the prepared sample consists of particles in the range of 45 nm and homogenous particle size distribution. The sample of zirconia has excellent tissue biocompatibility and does not show any toxicity towards normal 3T3 mouse fibroblast cells. It also inhibited the bacterial growth. The sample shows stability at physiological condition and does not show degradation. (author)

  16. Novel method for synthesis of silver nanoparticles and their application on wool

    Energy Technology Data Exchange (ETDEWEB)

    Boroumand, Majid Nasiri [Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Montazer, Majid [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Simon, Frank [Leibniz-Institut für Polymerforschung Dresden e.V., Dresden (Germany); Liesiene, Jolanta [Faculty of Chemical Technology, Kaunas University of Technology, Kaunas (Lithuania); Šaponjic, Zoran [Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade (Serbia); Dutschk, Victoria, E-mail: v.dutschk@utwente.nl [Faculty of Engineering Technology, University of Twente, Enschede (Netherlands)

    2015-08-15

    Graphical abstract: Tentative mechanism for reduction of Ag{sup +} by polyphenols having two hydroxy groups in ortho-position – the use of silver nanoparticles and an aqueous solution of extracted dye from Pomegranate peel as a reducing agent for synthesis silver nanoparticles from silver nitrate. - Highlights: • A new method for the synthesis of silver nanoparticles suitable to impart antibacterial properties of wool fabric proposed. • Silver nanopartilces were synthesized by a biochemical reduction method. • An aqueous solution of extracted dye from Pomegranate peel was used as a reducing agent for synthesis of silver nanoparticles from silver nitrate. - Abstract: In this study, a new method for the synthesis of silver nanoparticles (AgNPs) suitable to impart antibacterial properties of wool fabric is proposed. AgNPs were synthesized by a biochemical reduction method. An aqueous solution of extracted dye from Pomegranate peel was used as a reducing agent for the synthesis of AgNPs from silver nitrate. The ratio of dye to silver nitrate concentration (R{sub Dye}/{sub Ag} = [Dye]/[AgNO{sub 3}]) is the influencing factor in the synthesis of silver nanoparticles. The nanoparticles formation was followed by UV/Vis absorption spectroscopy. The size and shape of AgNPs were studied by transmission electron microscopy (TEM). The size distribution and Zetapotential of nanoparticles were evaluated using diffraction light scattering (DLS) measurements. The antibacterial potential of biosynthesized silver nanoparticles against Escherichia coli (E. coli) was examined qualitatively and quantitatively. Kinetic analysis of the bacteria reduction using AgNPs synthesized in different way was performed. AgNPs were applied on wool fabrics by exhaustion. The changes in surface morphology of wool fibers after AgNPs loading were studied using scanning electron microscopy (SEM). The amounts of silver deposited on wool fabrics at different pH and temperature were compared applying

  17. Command Generator Tracker Synthesis Methods Using an LQG (Linear System Model, Quadratic Cost, and Gaussian Noise Process) Derived Proportional Plus Integral Controller Based on the Integral of the Regulation Error.

    Science.gov (United States)

    1983-12-01

    34 M4 + + Z + + + E + ass + + Z + + + osi " " + + Z + + + + 9tr"- + t + Z + ++ +" + + L + Z + +0+ + : :L:+: • +: E. . :ce + L+ Z+ + E+ 9 " + L z + K...this guide.) The truth model description is identified by the heading "TRUTH MODELO . The matrices of the continuous-time system are listed first. The

  18. Facile method for the synthesis of gold nanoparticles using an ion coater

    Science.gov (United States)

    Lee, Seung Han; Jung, Hyun Kyu; Kim, Tae Cheol; Kim, Chang Hee; Shin, Chang Hwan; Yoon, Tae-Sik; Hong, A.-Ra; Jang, Ho Seong; Kim, Dong Hun

    2018-03-01

    Herein we report a metal nanoparticle synthesis method based on a physical vapor deposition process instead of the conventional wet process of chemical reactions in liquids. A narrow size distribution of synthesized gold nanoparticles was obtained using an ion coater on glycerin at low vapor pressure. The nanoparticle size could be modulated by controlling the sputtering conditions especially the discharge current. Due to the formation of gold nanoparticles, a surface plasmon resonance peak appeared at

  19. Methods for the synthesis of aza(deaza)xanthines as a basis of biologically active compounds

    International Nuclear Information System (INIS)

    Babkov, D A; Geisman, A N; Novikov, M S; Khandazhinskaya, A L

    2016-01-01

    The review covers methods for the synthesis of aza(deaza)xanthines, i.e., fused pyrrolo-, pyrazolo- and triazolopyrimidine heterocyclic systems, which are common core structures of various biologically active compounds. The extensive range of modern synthetic approaches is organized according to target structures and starting building blocks. The presented material is intended to benefit broad audience of specialists in the fields of organic, medicinal and pharmaceutical chemistry. The bibliography includes 195 references

  20. Methods for the synthesis of aza(deaza)xanthines as a basis of biologically active compounds

    Science.gov (United States)

    Babkov, D. A.; Geisman, A. N.; Khandazhinskaya, A. L.; Novikov, M. S.

    2016-03-01

    The review covers methods for the synthesis of aza(deaza)xanthines, i.e., fused pyrrolo-, pyrazolo- and triazolopyrimidine heterocyclic systems, which are common core structures of various biologically active compounds. The extensive range of modern synthetic approaches is organized according to target structures and starting building blocks. The presented material is intended to benefit broad audience of specialists in the fields of organic, medicinal and pharmaceutical chemistry. The bibliography includes 195 references.

  1. Model Uncertainty Quantification Methods In Data Assimilation

    Science.gov (United States)

    Pathiraja, S. D.; Marshall, L. A.; Sharma, A.; Moradkhani, H.

    2017-12-01

    Data Assimilation involves utilising observations to improve model predictions in a seamless and statistically optimal fashion. Its applications are wide-ranging; from improving weather forecasts to tracking targets such as in the Apollo 11 mission. The use of Data Assimilation methods in high dimensional complex geophysical systems is an active area of research, where there exists many opportunities to enhance existing methodologies. One of the central challenges is in model uncertainty quantification; the outcome of any Data Assimilation study is strongly dependent on the uncertainties assigned to both observations and models. I focus on developing improved model uncertainty quantification methods that are applicable to challenging real world scenarios. These include developing methods for cases where the system states are only partially observed, where there is little prior knowledge of the model errors, and where the model error statistics are likely to be highly non-Gaussian.

  2. Sound Synthesis and Musical Composition by Physical Modelling of Self-Sustained Oscillating Structures

    OpenAIRE

    Poyer, François; Cadoz, Claude

    2007-01-01

    Paper 3 - Audio Synthesis (Oral Presentations); International audience; In this paper, we present the first results of a study that is carried out with the sound synthesis and musical creation environment GENESIS on self-sustained oscillating structures models. Based on the mass-interaction CORDIS-ANIMA physical modelling formalism, GENESIS has got the noteworthy property that it allows to work both on sound itself and on musical composition in a single coherent environment. By taking as a st...

  3. Visual Representation in GENESIS as a tool for Physical Modeling, Sound Synthesis and Musical Composition

    OpenAIRE

    Villeneuve, Jérôme; Cadoz, Claude; Castagné, Nicolas

    2015-01-01

    The motivation of this paper is to highlight the importance of visual representations for artists when modeling and simulating mass-interaction physical networks in the context of sound synthesis and musical composition. GENESIS is a musician-oriented software environment for sound synthesis and musical composition. However, despite this orientation, a substantial amount of effort has been put into building a rich variety of tools based on static or dynamic visual representations of models an...

  4. A Method for Model Checking Feature Interactions

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Le Guilly, Thibaut; Ravn, Anders Peter

    2015-01-01

    This paper presents a method to check for feature interactions in a system assembled from independently developed concurrent processes as found in many reactive systems. The method combines and refines existing definitions and adds a set of activities. The activities describe how to populate the ...... the definitions with models to ensure that all interactions are captured. The method is illustrated on a home automation example with model checking as analysis tool. In particular, the modelling formalism is timed automata and the analysis uses UPPAAL to find interactions....

  5. Novel Methods for the Chemical Synthesis of Insulin Superfamily Peptides and of Analogues Containing Disulfide Isosteres.

    Science.gov (United States)

    Hossain, Mohammed Akhter; Wade, John D

    2017-09-19

    The insulin superfamily of peptides is ubiquitous within vertebrates and invertebrates and is characterized by the presence of a set of three disulfide bonds in a unique disposition. With the exception of insulin-like growth factors I and II, which are single chain peptides, the remaining 8 members of the human insulin superfamily are two-chain peptides containing one intramolecular and two intermolecular disulfide bridges. These structural features have long made the chemical synthesis of the peptides a considerable challenge, in particular, including their correct disulfide bond pairing and formation. However, they have also afforded the opportunity to develop modern solid phase synthesis methods for the preparation of such peptides that incorporate novel or improved chemical methods for the controlled introduction of both disulfide bonds and their surrogates, both during and after peptide chain assembly. In turn, this has enabled a detailed probing of the structure and function relationship of this small but complex superfamily of peptides. After initially using and subsequently identifying significant limitations of the approach of simultaneous random chain combination and oxidative folding, our laboratory undertook to develop robust chemical synthesis strategies in concert with orthogonal cysteine S-protecting groups and corresponding regioselective disulfide bond formation. These have included the separate synthesis of each of the two chains or of the two chains linked by an artificial C-peptide that is removed following postoxidative folding. These, in turn, have enabled an increased ease of acquisition in a good yield of not only members of human insulin superfamily but other insulin-like peptides. Importantly, these successful methods have enabled, for the first time, a detailed analysis of the role that the disulfide bonds play in the structure and function of such peptides. This was achieved by selective removal of the disulfide bonds or by the judicious

  6. Structural equation modeling methods and applications

    CERN Document Server

    Wang, Jichuan

    2012-01-01

    A reference guide for applications of SEM using Mplus Structural Equation Modeling: Applications Using Mplus is intended as both a teaching resource and a reference guide. Written in non-mathematical terms, this book focuses on the conceptual and practical aspects of Structural Equation Modeling (SEM). Basic concepts and examples of various SEM models are demonstrated along with recently developed advanced methods, such as mixture modeling and model-based power analysis and sample size estimate for SEM. The statistical modeling program, Mplus, is also featured and provides researchers with a

  7. Level Crossing Methods in Stochastic Models

    CERN Document Server

    Brill, Percy H

    2008-01-01

    Since its inception in 1974, the level crossing approach for analyzing a large class of stochastic models has become increasingly popular among researchers. This volume traces the evolution of level crossing theory for obtaining probability distributions of state variables and demonstrates solution methods in a variety of stochastic models including: queues, inventories, dams, renewal models, counter models, pharmacokinetics, and the natural sciences. Results for both steady-state and transient distributions are given, and numerous examples help the reader apply the method to solve problems fa

  8. Microfluidic very large scale integration (VLSI) modeling, simulation, testing, compilation and physical synthesis

    CERN Document Server

    Pop, Paul; Madsen, Jan

    2016-01-01

    This book presents the state-of-the-art techniques for the modeling, simulation, testing, compilation and physical synthesis of mVLSI biochips. The authors describe a top-down modeling and synthesis methodology for the mVLSI biochips, inspired by microelectronics VLSI methodologies. They introduce a modeling framework for the components and the biochip architecture, and a high-level microfluidic protocol language. Coverage includes a topology graph-based model for the biochip architecture, and a sequencing graph to model for biochemical application, showing how the application model can be obtained from the protocol language. The techniques described facilitate programmability and automation, enabling developers in the emerging, large biochip market. · Presents the current models used for the research on compilation and synthesis techniques of mVLSI biochips in a tutorial fashion; · Includes a set of "benchmarks", that are presented in great detail and includes the source code of several of the techniques p...

  9. Numerical methods and modelling for engineering

    CERN Document Server

    Khoury, Richard

    2016-01-01

    This textbook provides a step-by-step approach to numerical methods in engineering modelling. The authors provide a consistent treatment of the topic, from the ground up, to reinforce for students that numerical methods are a set of mathematical modelling tools which allow engineers to represent real-world systems and compute features of these systems with a predictable error rate. Each method presented addresses a specific type of problem, namely root-finding, optimization, integral, derivative, initial value problem, or boundary value problem, and each one encompasses a set of algorithms to solve the problem given some information and to a known error bound. The authors demonstrate that after developing a proper model and understanding of the engineering situation they are working on, engineers can break down a model into a set of specific mathematical problems, and then implement the appropriate numerical methods to solve these problems. Uses a “building-block” approach, starting with simpler mathemati...

  10. Methods of Synthesis, Properties and Biomedical Applications of CuO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Madalina Elena Grigore

    2016-11-01

    Full Text Available This study aims to provide an updated survey of the main synthesis methods of copper oxide (CuO nanoparticles in order to obtain tailored nanosystems for various biomedical applications. The synthesis approach significantly impacts the properties of such nanoparticles and these properties in turn have a significant impact on their biomedical applications. Although not widely investigated as an efficient drug delivery system, CuO nanoparticles have great biological properties including effective antimicrobial action against a wide range of pathogens and also drug resistant bacteria. These properties have led to the development of various approaches with direct applications to the biomedical field, such as tailored surfaces with antimicrobial effect, wound dressings and modified textiles. It is also believed that these nanosystems could represent efficient alternatives in the development of smart systems utilized both for the detection of pathogens and for the treatment of infections.

  11. Production of advanced materials by methods of self-propagating high-temperature synthesis

    CERN Document Server

    Tavadze, Giorgi F

    2013-01-01

    This translation from the original Russian book outlines the production of a variety of materials by methods of self-propagating high-temperature synthesis (SHS). The types of materials discussed include: hard, refractory, corrosion and wear-resistant materials, as well as other advanced and speciality materials. The authors address the issue of optimal parameters for SHS reactions occurring during processes involving a preliminary metallothermic reduction stage, and they calculate this using thermodynamic approaches. In order to confirm the effectiveness of this approach, the authors describe experiments focussing on the synthesis of elemental crysalline boron, boron carbides and nitrides. Other parts of this brief include theoretical and experimental results on single-stage production of hard alloys on the basis of titanium and zirconium borides, as well as macrokinetics of degassing and compaciton of SHS-products.This brief is suitable for academics, as well as those working in industrial manufacturing com...

  12. Methods of Synthesis, Properties and Biomedical Applications of CuO Nanoparticles

    Science.gov (United States)

    Grigore, Madalina Elena; Biscu, Elena Ramona; Holban, Alina Maria; Gestal, Monica Cartelle; Grumezescu, Alexandru Mihai

    2016-01-01

    This study aims to provide an updated survey of the main synthesis methods of copper oxide (CuO) nanoparticles in order to obtain tailored nanosystems for various biomedical applications. The synthesis approach significantly impacts the properties of such nanoparticles and these properties in turn have a significant impact on their biomedical applications. Although not widely investigated as an efficient drug delivery system, CuO nanoparticles have great biological properties including effective antimicrobial action against a wide range of pathogens and also drug resistant bacteria. These properties have led to the development of various approaches with direct applications to the biomedical field, such as tailored surfaces with antimicrobial effect, wound dressings and modified textiles. It is also believed that these nanosystems could represent efficient alternatives in the development of smart systems utilized both for the detection of pathogens and for the treatment of infections. PMID:27916867

  13. Facile Synthesis of Ultrafine Gd2O3 Nanoparticles by Polyol Microwave Method

    Science.gov (United States)

    Trinh, Le Huu; Hoa, Tran Thai; Van Hieu, Nguyen; Cuong, Nguyen Duc

    2017-06-01

    Gd2O3 nanoparticles have been quickly synthesized by a modified polyol method with microwave assistance. Triethylene glycol (TEG) was used as solvent and surfactant stabilizing agent. Systematic characterization of the TEG-coated gadolinium oxide nanoparticles (Gd2O3@TEG) showed that average particle size of 1 nm, 5 nm, and 10 nm could be obtained by changing some synthesis conditions. It was found that, after thermal treatment at 700°C, Gd2O3 nanoparticles showed uniform spherical shape with unchanged average particle size in comparison with the Gd2O3@TEG precursor. This approach is simple and rapid and can be easily scaled up and potentially extended to synthesis of other oxides.

  14. Synthesis and size control of monodisperse copper nanoparticles by polyol method.

    Science.gov (United States)

    Park, Bong Kyun; Jeong, Sunho; Kim, Dongjo; Moon, Jooho; Lim, Soonkwon; Kim, Jang Sub

    2007-07-15

    We describe herein the synthesis of metallic copper nanoparticles in the presence of poly(vinylpyrrolidone), employed as a protecting agent, via a polyol method in ambient atmosphere. The obtained copper particles were confirmed by XRD to be crystalline copper with a face-centered cubic (fcc) structure. We observed monodisperse spherical copper nanoparticles with a diameter range 45+/-8 nm. The particle size and its distribution are controlled by varying the synthesis parameters such as the reducing agent concentration, reaction temperature, and precursor injection rate. The precursor injection rate plays an important role in controlling the size of the copper nanoparticles. On the basis of XPS and HRTEM results, we demonstrate that the surface of the copper is surrounded by amorphous CuO and that poly(vinylpyrrolidone) is chemisorbed on the copper surface.

  15. Synthesis of novel chalcone derivatives by conventional and microwave irradiation methods and their pharmacological activities

    Directory of Open Access Journals (Sweden)

    Mohammed Rayees Ahmad

    2016-09-01

    Full Text Available Chalcones are abundant in edible plants and are considered to be the precursors of flavonoids and isoflavonoids. Chalcones belong to an important class of flavonoids, which may be prepared by Claisen–Schmidt condensation. They possess a wide range of biological activities and industrial applications. The cytotoxicity against tumour cell lines may be the result of disruption of the cell cycle, inhibition of angiogenesis, interference with p53-MDM2 interaction, mitochondrial uncoupling or induction of apoptosis. Chalcones are synthesized by conventional and microwave assisted synthesis methods. By microwave assisted synthesis, a considerable increase in the reaction rate has been observed and that too, with better yields. The compounds have been screened for cytotoxic activity and antioxidant activity.

  16. Synthesis and characterization of copper nanoparticles by using the exploding wire method

    International Nuclear Information System (INIS)

    Das, Rashmita; Das, Basanta Kumar; Shyam, Anurag

    2012-01-01

    During the past few years, the synthesis of copper nanoparticles has attracted much attention because of their huge potential for replacing the expensive nano silver inks utilized in conductive printing. This opens a new possibility in printed electronics. Copper-based inkjet inks can be used to form various devices such as solar cells, RF identification tags and electroluminescence devices. This paper describes controlled synthesis of pure copper nanoparticles, mainly by using the exploding wire method. A wire of 0.26 mm in diameter was exploded in a nitrogen environment. The sample was characterized by using X-ray diffraction (XRD) and atomic force microscopy (AFM). XRD revealed the presence of pure copper and AFM revealed the presence of nanoparticles with an average size of 55 nm.

  17. Synthesis of anhydrous K2TiOF4 via a mild hydrothermal method

    Science.gov (United States)

    Felder, Justin B.; Yeon, Jeongho; zur Loye, Hans-Conrad

    2015-10-01

    The synthesis of anhydrous K2TiOF4 has been previously attempted by transforming precursor compounds, such as the peroxide (K2Ti(O2)F4), hydrate (K2TiOF4·H2O) and fluoride (K2TiF6). Due to the large structural differences between these precursors and the anhydrous oxyfluorides, however, these preparations have been unsuccessful. Therefore, a direct method of synthesis has been employed to grow single crystals of K2TiOF4 that were characterized by single crystal x-ray diffraction. K2TiOF4 was found to be isostructural with the previously known K2VOF4.

  18. Physically Informed Signal Processing Methods for Piano Sound Synthesis: A Research Overview

    Directory of Open Access Journals (Sweden)

    Avanzini Federico

    2003-01-01

    Full Text Available This paper reviews recent developments in physics-based synthesis of piano. The paper considers the main components of the instrument, that is, the hammer, the string, and the soundboard. Modeling techniques are discussed for each of these elements, together with implementation strategies. Attention is focused on numerical issues, and each implementation technique is described in light of its efficiency and accuracy properties. As the structured audio coding approach is gaining popularity, the authors argue that the physical modeling approach will have relevant applications in the field of multimedia communication.

  19. Biological evaluation and simple method for the synthesis of tetrahydrobenzo[a]xanthenes-11-one derivatives

    Directory of Open Access Journals (Sweden)

    Ali Akbari

    2017-01-01

    Full Text Available A simple method for the synthesis of Tetrahydrobenzo[a]xanthenes-11-one derivatives in the presence of BF3.SiO2, and its antibacterial activity was assessed against Pseudomonas syringae, Xanthomonas citi and Pectobacterium carotovorum. The structure of the isolated compounds has been determined by means of 1H/13C NMR and FT-IR spectroscopy. The reactions were carried out in water at room temperature for 5 h. This method has some advantages such as good to excellent yield, mild reaction condition, ease of operation and workup, high product purity and green process.

  20. Modeling complex work systems - method meets reality

    NARCIS (Netherlands)

    van der Veer, Gerrit C.; Hoeve, Machteld; Lenting, Bert

    1996-01-01

    Modeling an existing task situation is often a first phase in the (re)design of information systems. For complex systems design, this model should consider both the people and the organization involved, the work, and situational aspects. Groupware Task Analysis (GTA) as part of a method for the

  1. The housing market: modeling and assessment methods

    Directory of Open Access Journals (Sweden)

    Zapadnjuk Evgenij Aleksandrovich

    2016-10-01

    Full Text Available This paper analyzes the theoretical foundations of econometric simulation model that can be used to study the housing sector. Shows the methods of the practical use of correlation and regression models in the analysis of the status and prospects of development of the housing market.

  2. Dependencies of photoelectric properties of SiC/Si structures grown by the method of atoms substitution on synthesis time

    Science.gov (United States)

    Grashchenko, A. S.; Kukushkin, S. A.; Osipov, A. V.; Feoktistov, N. A.

    2017-07-01

    This paper is dedicated to an exploration of the photoelectric properties of Si-SiC structures grown by the substitution method on silicon substrates of (001) orientation. For the samples with the synthesis times of 40, 60, 90, 120 and 900 s, magnitudes of the saturation currents are determined and the coefficients of efficiency are calculated. The obtained dependencies of the photoelectric characteristics on the synthesis time are explained using the theory of formation of dilatation dipoles during the synthesis by the method of atoms substitution.

  3. The Dietary Patterns Methods Project: Synthesis of Findings across Cohorts and Relevance to Dietary Guidance1234

    Science.gov (United States)

    Liese, Angela D; Krebs-Smith, Susan M; Subar, Amy F; George, Stephanie M; Harmon, Brook E; Neuhouser, Marian L; Boushey, Carol J; Schap, TusaRebecca E; Reedy, Jill

    2015-01-01

    The Dietary Patterns Methods Project (DPMP) was initiated in 2012 to strengthen research evidence on dietary indices, dietary patterns, and health for upcoming revisions of the Dietary Guidelines for Americans, given that the lack of consistent methodology has impeded development of consistent and reliable conclusions. DPMP investigators developed research questions and a standardized approach to index-based dietary analysis. This article presents a synthesis of findings across the cohorts. Standardized analyses were conducted in the NIH-AARP Diet and Health Study, the Multiethnic Cohort, and the Women’s Health Initiative Observational Study (WHI-OS). Healthy Eating Index 2010, Alternative Healthy Eating Index 2010 (AHEI-2010), alternate Mediterranean Diet, and Dietary Approaches to Stop Hypertension (DASH) scores were examined across cohorts for correlations between pairs of indices; concordant classifications into index score quintiles; associations with all-cause, cardiovascular disease (CVD), and cancer mortality with the use of Cox proportional hazards models; and dietary intake of foods and nutrients corresponding to index quintiles. Across all cohorts in women and men, there was a high degree of correlation and consistent classifications between index pairs. Higher diet quality (top quintile) was significantly and consistently associated with an 11–28% reduced risk of death due to all causes, CVD, and cancer compared with the lowest quintile, independent of known confounders. This was true for all diet index–mortality associations, with the exception of AHEI-2010 and cancer mortality in WHI-OS women. In all cohorts, survival benefit was greater with a higher-quality diet, and relatively small intake differences distinguished the index quintiles. The reductions in mortality risk started at relatively lower levels of diet quality. Higher scores on each of the indices, signifying higher diet quality, were associated with marked reductions in mortality

  4. Improving the time efficiency of the Fourier synthesis method for slice selection in magnetic resonance imaging.

    Science.gov (United States)

    Tahayori, B; Khaneja, N; Johnston, L A; Farrell, P M; Mareels, I M Y

    2016-01-01

    The design of slice selective pulses for magnetic resonance imaging can be cast as an optimal control problem. The Fourier synthesis method is an existing approach to solve these optimal control problems. In this method the gradient field as well as the excitation field are switched rapidly and their amplitudes are calculated based on a Fourier series expansion. Here, we provide a novel insight into the Fourier synthesis method via representing the Bloch equation in spherical coordinates. Based on the spherical Bloch equation, we propose an alternative sequence of pulses that can be used for slice selection which is more time efficient compared to the original method. Simulation results demonstrate that while the performance of both methods is approximately the same, the required time for the proposed sequence of pulses is half of the original sequence of pulses. Furthermore, the slice selectivity of both sequences of pulses changes with radio frequency field inhomogeneities in a similar way. We also introduce a measure, referred to as gradient complexity, to compare the performance of both sequences of pulses. This measure indicates that for a desired level of uniformity in the excited slice, the gradient complexity for the proposed sequence of pulses is less than the original sequence. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  5. Exploration and characterization of new synthesis methods for C60 colloidal suspensions in water

    Science.gov (United States)

    Hilburn, Martha E.

    Buckminsterfullerene, C60, has been used in the production of several commercial products from badminton racquets and lubricants for their mechanical properties to cosmetics and even dietary supplements for their "antioxidant" properties. Multi-ton production of C60 began in 2003 encouraging serious consideration of its fate in the environment in the case of an accidental release or improper disposal. Although C60 is practically insoluble in water, it readily forms stable aqueous colloidal suspensions (termed nC60) through solvent exchange methods or long-term vigorous stirring in water. Two new solvent exchange methods for synthesizing nC60 are presented. These methods combine key advantages of multiple existing synthesis methods including high yield, narrow particle size distribution, short synthesis time, and an absence of solvents such as tetrahydrofuran that have historically caused problems in laboratory synthesized aggregates. The resulting samples are attractive candidates for use in controlled environmental impact, biological, and toxicity studies. An improved method for quantifying residual solvents in nC60 samples utilizing solid phase micro extraction gas chromatography mass spectrometry (SPME-GC-MS) is also discussed.

  6. Modeling ground vehicle acoustic signatures for analysis and synthesis

    International Nuclear Information System (INIS)

    Haschke, G.; Stanfield, R.

    1995-01-01

    Security and weapon systems use acoustic sensor signals to classify and identify moving ground vehicles. Developing robust signal processing algorithms for this is expensive, particularly in presence of acoustic clutter or countermeasures. This paper proposes a parametric ground vehicle acoustic signature model to aid the system designer in understanding which signature features are important, developing corresponding feature extraction algorithms and generating low-cost, high-fidelity synthetic signatures for testing. The authors have proposed computer-generated acoustic signatures of armored, tracked ground vehicles to deceive acoustic-sensored smart munitions. They have developed quantitative measures of how accurately a synthetic acoustic signature matches those produced by actual vehicles. This paper describes parameters of the model used to generate these synthetic signatures and suggests methods for extracting these parameters from signatures of valid vehicle encounters. The model incorporates wide-bandwidth and narrow- bandwidth components that are modulated in a pseudo-random fashion to mimic the time dynamics of valid vehicle signatures. Narrow- bandwidth feature extraction techniques estimate frequency, amplitude and phase information contained in a single set of narrow frequency- band harmonics. Wide-bandwidth feature extraction techniques estimate parameters of a correlated-noise-floor model. Finally, the authors propose a method of modeling the time dynamics of the harmonic amplitudes as a means adding necessary time-varying features to the narrow-bandwidth signal components. The authors present results of applying this modeling technique to acoustic signatures recorded during encounters with one armored, tracked vehicle. Similar modeling techniques can be applied to security systems

  7. Finite-Element Model-Based Design Synthesis of Axial Flux PMBLDC Motors

    DEFF Research Database (Denmark)

    Fasil, Muhammed; Mijatovic, Nenad; Jensen, Bogi Bech

    2016-01-01

    This paper discusses design synthesis of a permanent magnet brushless DC (PMBLDC) machine using a finite element (FE) model. This work differentiates itself from the past studies by following a synthesis approach, in which many designs that satisfy performance criteria are considered instead...... of a unique solution. The designer can later select a design, based on comparing parameters of the designs, which are critical to the application that the motor will be used. The presented approach makes it easier to define constraints for a design synthesis problem. A detailed description of the setting up...... is demonstrated by designing a segmented axial torus PMBLDC motor for an electric two-wheeler....

  8. New method of synthesis and in vitro studies of a porous biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Wers, E., E-mail: wers.eric@hotmail.com [Equipe Chimie du Solide et Matériaux, UMR CNRS 6226, Sciences Chimiques de Rennes, Université de Rennes 1, Université Européenne de Bretagne, 263 avenue du Général Leclerc, 35042 Rennes Cedex (France); Lefeuvre, B. [Equipe Chimie du Solide et Matériaux, UMR CNRS 6226, Sciences Chimiques de Rennes, Université de Rennes 1, Université Européenne de Bretagne, 263 avenue du Général Leclerc, 35042 Rennes Cedex (France); Pellen-Mussi, P.; Novella, A. [Equipe Chimie du Solide et Matériaux, UMR CNRS 6226, Sciences Chimiques de Rennes, Université de Rennes 1, Université Européenne de Bretagne, 2 avenue du Professeur Léon Bernard, 35042 Rennes Cedex (France); Oudadesse, H. [Equipe Chimie du Solide et Matériaux, UMR CNRS 6226, Sciences Chimiques de Rennes, Université de Rennes 1, Université Européenne de Bretagne, 263 avenue du Général Leclerc, 35042 Rennes Cedex (France)

    2016-04-01

    Biomaterials for bone reconstruction represent a widely studied area. In this paper, a new method of synthesis of a porous glass–ceramic obtained by thermal treatment is presented. The prepared biomaterial was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and induced couple plasma-optical emission spectroscopy (ICP-OES), mercury porosimetry and by the Archimedes method. In vitro evaluations in a simulated body fluid (SBF) and in contact with SaOS{sub 2} human osteoblasts were also carried out. The porous glass–ceramic is composed of a total porous network of 60% suitable for body fluid and cell infiltration, with pore sizes varying from 60 nm to 143 μm. The presence of two crystalline phases decreases the kinetic of bioactivity compared to an amorphous biomaterial (bioactive glass). A hydroxyapatite layer appears from 15 days of immersion on the surface and inside the pores, showing a biodegradation and a bioactivity in four steps. Cytotoxicity assessments present an increase of the cellular viability after 72 h proving the non-cytotoxic effect of the glass–ceramic. Thus, the results of these different studies indicate that the porous biomaterial may have a potential application for the bone regeneration. This paper also presents the novelty of this method. It is a rapid synthesis which combines simplicity and low cost. This represents an advantage for an eventual industrialization. - Highlights: • The new method of synthesis of a porous glass–ceramic is reproducible. • The porous glass–ceramic possesses a total porosity of 60%. • The biomaterial shows a bioactivity in four steps with hydroxyapatite formation. • 82% of cellular viability is observed on the surface of the biomaterial.

  9. Shape Synthesis from Sketches via Procedural Models and Convolutional Networks.

    Science.gov (United States)

    Huang, Haibin; Kalogerakis, Evangelos; Yumer, Ersin; Mech, Radomir

    2017-08-01

    Procedural modeling techniques can produce high quality visual content through complex rule sets. However, controlling the outputs of these techniques for design purposes is often notoriously difficult for users due to the large number of parameters involved in these rule sets and also their non-linear relationship to the resulting content. To circumvent this problem, we present a sketch-based approach to procedural modeling. Given an approximate and abstract hand-drawn 2D sketch provided by a user, our algorithm automatically computes a set of procedural model parameters, which in turn yield multiple, detailed output shapes that resemble the user's input sketch. The user can then select an output shape, or further modify the sketch to explore alternative ones. At the heart of our approach is a deep Convolutional Neural Network (CNN) that is trained to map sketches to procedural model parameters. The network is trained by large amounts of automatically generated synthetic line drawings. By using an intuitive medium, i.e., freehand sketching as input, users are set free from manually adjusting procedural model parameters, yet they are still able to create high quality content. We demonstrate the accuracy and efficacy of our method in a variety of procedural modeling scenarios including design of man-made and organic shapes.

  10. REMOTE SYNTHESIS AND CONTROL INFORMATION TECHNOLOGY OF SYSTEM-DYNAMIC MODELS

    Directory of Open Access Journals (Sweden)

    A. V. Masloboev

    2015-07-01

    Full Text Available The general line of research is concerned with development of information technologies and computer simulation tools for management information and analytical support of complex semistructured systems. Regional socio-economic systems are consideredas a representative of this system type. Investigation is carried out within the bounds of development strategy implementation of the Arctic zone of the Russian Federation and national safety until 2020 in the Murmansk region, specifically under engineering of high end information infrastructure for innovation and security control problem-solving of regional development. Research methodology consists of system dynamics modeling method, distributed information system engineering technologies, pattern-based modeling and design techniques. The work deals with development of toolkit for decision-making information support problem-solving in the field of innovation security management of regional economics. For that purpose a system-dynamic models suite of innovation process standard components and information technology for remote formation and control of innovation business simulation models under research have been developed. Designed toolkit provides innovation security index dynamics forecasting and innovation business effectiveness of regional economics. Information technology is implemented within the bounds of thin client architecture and is intended for simulation models design process automation of complex systems. Technology implementation software tools provide pattern-based system-dynamic models distributed formation and simulation control of innovation processes. The technology provides availability and reusability index enhancement of information support facilities in application to innovation process simulation at the expense of distributed access to innovation business simulation modeling tools and model synthesis by the reusable components, simulating standard elements of innovation

  11. Measurement error models, methods, and applications

    CERN Document Server

    Buonaccorsi, John P

    2010-01-01

    Over the last 20 years, comprehensive strategies for treating measurement error in complex models and accounting for the use of extra data to estimate measurement error parameters have emerged. Focusing on both established and novel approaches, ""Measurement Error: Models, Methods, and Applications"" provides an overview of the main techniques and illustrates their application in various models. It describes the impacts of measurement errors on naive analyses that ignore them and presents ways to correct for them across a variety of statistical models, from simple one-sample problems to regres

  12. Learning spinal manipulation: A best-evidence synthesis of teaching methods.

    Science.gov (United States)

    Stainsby, Brynne E; Clarke, Michelle C S; Egonia, Jade R

    2016-10-01

    The purpose of this study was to evaluate the effectiveness of different reported methods used to teach spinal manipulative therapy to chiropractic students. For this best-evidence literature synthesis, 5 electronic databases were searched from 1900 to 2015. Eligible studies were critically appraised using the criteria of the Scottish Intercollegiate Guidelines Network. Scientifically admissible studies were synthesized following best-evidence synthesis principles. Twenty articles were critically appraised, including 9 randomized clinical trials, 9 cohort studies, and 2 systematic reviews/meta-analyses. Eleven articles were accepted as scientifically admissible. The type of teaching method aids included a Thrust in Motion cervical manikin, instrumented cardiopulmonary reanimation manikin, padded contact with a load cell, instrumented treatment table with force sensor/transducer, and Dynadjust instrument. Several different methods exist in the literature for teaching spinal manipulative therapy techniques; however, future research in this developing area of chiropractic education is proposed. It is suggested that various teaching methods be included in the regular curricula of chiropractic colleges to aid in developing manipulation skills, efficiency, and knowledge of performance.

  13. Parametric Hidden Markov Models for Recognition and Synthesis of Movements

    DEFF Research Database (Denmark)

    Herzog, Dennis; Krüger, Volker; Grest, Daniel

    2008-01-01

    In humanoid robotics, the recognition and synthesis of parametric movements plays an extraordinary role for robot human interaction. Such a parametric movement is a movement of a particular type (semantic), for example, similar pointing movements performed at different table-top positions. For un...

  14. A Synthesis of Equilibrium and Historical Models of Landform Development.

    Science.gov (United States)

    Renwick, William H.

    1985-01-01

    The synthesis of two approaches that can be used in teaching geomorphology is described. The equilibrium approach explains landforms and landform change in terms of equilibrium between landforms and controlling processes. The historical approach draws on climatic geomorphology to describe the effects of Quaternary climatic and tectonic events on…

  15. Global Optimization Ensemble Model for Classification Methods

    Directory of Open Access Journals (Sweden)

    Hina Anwar

    2014-01-01

    Full Text Available Supervised learning is the process of data mining for deducing rules from training datasets. A broad array of supervised learning algorithms exists, every one of them with its own advantages and drawbacks. There are some basic issues that affect the accuracy of classifier while solving a supervised learning problem, like bias-variance tradeoff, dimensionality of input space, and noise in the input data space. All these problems affect the accuracy of classifier and are the reason that there is no global optimal method for classification. There is not any generalized improvement method that can increase the accuracy of any classifier while addressing all the problems stated above. This paper proposes a global optimization ensemble model for classification methods (GMC that can improve the overall accuracy for supervised learning problems. The experimental results on various public datasets showed that the proposed model improved the accuracy of the classification models from 1% to 30% depending upon the algorithm complexity.

  16. A Method for Sustainable Carbon Dioxide Utilization Process Synthesis and Design

    DEFF Research Database (Denmark)

    Frauzem, Rebecca; Fjellerup, Kasper; Roh, Kosan

    for the process synthesis, design and more sustainable design. Using a superstructure-based approach a network of utilization alternatives is created linking CO2 and other raw materials with various products using processing blocks. This will then be optimized and verified for sustainability. Detailed design has...... also been performed for various case studies. These case studies include multiple pathways for the production of methanol and the production of dimethyl carbonate (DMC). From detailed design and analysis, CO2 conversion processes show promise as an additional method for the sustainable reduction of CO2...

  17. Nobel Prize in Chemistry. Development of the Olefin Metathesis Method in Organic Synthesis

    Science.gov (United States)

    Casey, Charles P.

    2006-02-01

    The 2005 Nobel Prize in Chemistry was awarded to Yves Chauvin of the Institut Français du Pétrole, Robert H. Grubbs of CalTech, and Richard R. Schrock of MIT "for development of the metathesis method in organic synthesis". The discoveries of the laureates provided a chemical reaction now used daily in the chemical industry for the efficient and more environmentally friendly production of important pharmaceuticals, fuels, synthetic fibers, and many other products. This article tells the story of how olefin metathesis became a truly useful synthetic transformation and a triumph for mechanistic chemistry, and illustrates the importance of fundamental research. See JCE Featured Molecules .

  18. Methods for the synthesis of O-, S- and N-vinyl derivatives

    Science.gov (United States)

    Ledovskaya, M. S.; Voronin, V. V.; Rodygin, K. S.

    2018-02-01

    The currently known methods for the preparation of vinyl ethers, vinyl sulfides and enamines are analyzed and described systematically. The published data on the reactions of alcohols, thiols and various nitrogen-containing compounds with acetylene, resulting in the corresponding vinyl derivatives, are considered. The attention is focused on the application of convenient acetylene sources. Other modern approaches to the synthesis of vinyl derivatives are described in detail, including vinyl exchange and metathesis reactions, various types of cross-coupling and cleavage of organic compounds. Some specific synthetic routes to vinyl ethers, vinyl sulfides and enamines are presented in the last Section. The bibliography includes 262 references.

  19. Synthesis of multiwalled carbon nanotube from different grades of carbon black using arc discharge method

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Neha, E-mail: n4neha31@gmail.com [Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani (India); Sharma, N. N. [Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani (India); Director, School of Automobile, Mechanical & Mechatronics, Manipal University,Jaipur,India (India)

    2016-04-13

    This paper describes the synthesis of nanotube from different grades (Tread * A(non-ASTM), N134,N121,N660 and N330)of carbon black using DC arc discharge method at 40A current for 60sec. Carbon black samples of different grades were procured from industry (Aditya Birla Science and Technology Limited, India). Scanning Electron Micrographs (SEM) of the deposited carbon nanostructures suggests that MWCNTs are formed at 40A and for a minimal exposure time of 60sec.The result formed indicates the N330 grade of carbon black gets converted to MWCNTs (Multiwall Carbon nanotube) as compared to other grades.

  20. Recent progress in the direct synthesis of hierarchical zeolites: synthetic strategies and characterization methods

    KAUST Repository

    Liu, Zhaohui

    2017-06-16

    Hierarchically structured zeolites combine the merits of microporous zeolites and mesoporous materials to offer enhanced molecular diffusion and mass transfer without compromising the inherent catalytic activities and selectivity of zeolites. This short review gives an introduction to the synthesis strategies for hierarchically structured zeolites with emphasis on the latest progress in the route of ‘direct synthesis’ using various templates. Several characterization methods that allow us to evaluate the ‘quality’ of complex porous structures are also introduced. At the end of this review, an outlook is given to discuss some critical issues and challenges regarding the development of novel hierarchically structured zeolites as well as their applications.

  1. Modelling methods for milk intake measurements

    International Nuclear Information System (INIS)

    Coward, W.A.

    1999-01-01

    One component of the first Research Coordination Programme was a tutorial session on modelling in in-vivo tracer kinetic methods. This section describes the principles that are involved and how these can be translated into spreadsheets using Microsoft Excel and the SOLVER function to fit the model to the data. The purpose of this section is to describe the system developed within the RCM, and how it is used

  2. Modelling asteroid brightness variations. I - Numerical methods

    Science.gov (United States)

    Karttunen, H.

    1989-01-01

    A method for generating lightcurves of asteroid models is presented. The effects of the shape of the asteroid and the scattering law of a surface element are distinctly separable, being described by chosen functions that can easily be changed. The shape is specified by means of two functions that yield the length of the radius vector and the normal vector of the surface at a given point. The general shape must be convex, but spherical concavities producing macroscopic shadowing can also be modeled.

  3. Modeling Storm Surges Using Discontinuous Galerkin Methods

    Science.gov (United States)

    2016-06-01

    STATEMENT Approved for public release; distribution is unlimited 12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words ) Storm surges have a...model. One of the governing systems of equations used to model storm surges’ effects is the Shallow Water Equations (SWE). In this thesis, we solve the...fundamental truth, we found the error norm of the implicit method to be minimal. This study focuses on the impacts of a simulated storm surge in La Push

  4. Optimal synthesis of a four-bar linkage by method of controlled deviation

    Directory of Open Access Journals (Sweden)

    Bulatović Radovan R.

    2004-01-01

    Full Text Available This paper considers optimal synthesis of a four-bar linkage by method of controlled deviations. The advantage of this approximate method is that it allows control of motion of the coupler in the four-bar linkage so that the path of the coupler is in the prescribed environment around the given path on the segment observed. The Hooke-Jeeves’s optimization algorithm has been used in the optimization process. Calculation expressions are not used as the method of direct searching, i.e. individual comparison of the calculated value of the objective function is made in each iteration and the moving is done in the direction of decreasing the value of the objective function. This algorithm does not depend on the initial selection of the projected variables. All this is illustrated on an example of synthesis of a four-bar linkage whose coupler point traces a straight line, i.e. passes through sixteen prescribed points lying on one straight line. .

  5. New method of synthesis and in vitro studies of a porous biomaterial.

    Science.gov (United States)

    Wers, E; Lefeuvre, B; Pellen-Mussi, P; Novella, A; Oudadesse, H

    2016-04-01

    Biomaterials for bone reconstruction represent a widely studied area. In this paper, a new method of synthesis of a porous glass-ceramic obtained by thermal treatment is presented. The prepared biomaterial was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and induced couple plasma-optical emission spectroscopy (ICP-OES), mercury porosimetry and by the Archimedes method. In vitro evaluations in a simulated body fluid (SBF) and in contact with SaOS2 human osteoblasts were also carried out. The porous glass-ceramic is composed of a total porous network of 60% suitable for body fluid and cell infiltration, with pore sizes varying from 60 nm to 143 μm. The presence of two crystalline phases decreases the kinetic of bioactivity compared to an amorphous biomaterial (bioactive glass). A hydroxyapatite layer appears from 15 days of immersion on the surface and inside the pores, showing a biodegradation and a bioactivity in four steps. Cytotoxicity assessments present an increase of the cellular viability after 72 h proving the non-cytotoxic effect of the glass-ceramic. Thus, the results of these different studies indicate that the porous biomaterial may have a potential application for the bone regeneration. This paper also presents the novelty of this method. It is a rapid synthesis which combines simplicity and low cost. This represents an advantage for an eventual industrialization. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Study of iterative synthesis method by deflation in the resolution of neutron diffusion equation applied to fast reactors calculation

    International Nuclear Information System (INIS)

    Reis Filho, P.E.G. dos

    1982-01-01

    A new synthesis method to substitute for the classical method of finite diferences for XYZ geometry (geometry of critical experiments in fast reactors), is developed. The new method allows a fine energy group division, that is, finer than the 6 groups division used in calculations of power core specification. (E.G.) [pt

  7. Sound Synthesis of the Harpsichord Using a Computationally Efficient Physical Model

    OpenAIRE

    Vesa Välimäki; Henri Penttinen; Mikael Laurson; Jonte Knif; Cumhur Erkut

    2004-01-01

    A sound synthesis algorithm for the harpsichord has been developed by applying the principles of digital waveguide modeling. A modification to the loss filter of the string model is introduced that allows more flexible control of decay rates of partials than is possible with a one-pole digital filter, which is a usual choice for the loss filter. A version of the commuted waveguide synthesis approach is used, where each tone is generated with a parallel combination of the string model and a s...

  8. Models and Methods for Free Material Optimization

    DEFF Research Database (Denmark)

    Weldeyesus, Alemseged Gebrehiwot

    conditions for physical attainability, in the context that, it has to be symmetric and positive semidefinite. FMO problems have been studied for the last two decades in many articles that led to the development of a wide range of models, methods, and theories. As the design variables in FMO are the local...... programs. The method has successfully obtained solutions to large-scale classical FMO problems of simultaneous analysis and design, nested and dual formulations. The second goal is to extend the method and the FMO problem formulations to general laminated shell structures. The thesis additionally addresses...

  9. Intelligent control of HVAC systems. Part I: Modeling and synthesis

    Directory of Open Access Journals (Sweden)

    Adrian TOADER

    2013-03-01

    Full Text Available This is the first part of a work on intelligent type control of Heating, Ventilating and Air-Conditioning (HVAC systems. The study is performed from the perspective of giving a unitary control method to ensure high energy efficiency and air quality improving. To illustrate the proposed HVAC control technique, in this first part it is considered as benchmark problem a single thermal space HVAC system. The construction of the mathematical model is performed only with a view to obtain a framework of HVAC intelligent control validation by numerical simulations. The latter will be reported in a second part of the study.

  10. Impact of synthesis methods on the transport of single walled carbon nanotubes in the aquatic environment.

    Science.gov (United States)

    Chowdhury, Indranil; Duch, Mathew C; Gits, Colton C; Hersam, Mark C; Walker, Sharon L

    2012-11-06

    In this study, a systematic approach has been followed to investigate the fate and transport of single walled carbon nanotubes (SWCNTs) from synthesis to environmentally relevant conditions. Three widely used SWCNT synthesis methods have been investigated in this study including high pressure carbon monoxide (HiPco), SWeNT CoMoCat, and electric arc discharge technique (EA). This study relates the transport of three SWCNTs (HiPco-D, SG65-D, and P2-D) with different synthesis methods and residual catalyst content revealing their influence on the subsequent fate of the nanotubes. To minimize nanotube bundling and aggregation, the SWCNTs were dispersed using the biocompatible triblock copolymer Pluronic, which allowed the comparison in the transport trends among these SWCNTs. After purification, the residual metal catalyst between the SWCNTs follows the trend: HiPco-D > SG65-D > P2-D. The electrophoretic mobility (EPM) and hydrodynamic diameter of SWCNTs remained insensitive to SWCNT type, pH, and presence of natural organic matter (NOM); but were affected by ionic strength (IS) and ion valence (K(+), Ca(2+)). In monovalent ions, the hydrodynamic diameter of SWCNTs was not influenced by IS, whereas larger aggregation was observed for HiPco-D with IS than P2-D and SG65-D in the presence of Ca(2+). Transport of HiPco-D in the porous media was significantly higher than SG65-D followed by P2-D. Release of HiPco-D from porous media was higher than SG65-D followed by P2-D, though negligible amount of all types of SWCNTs (transport and release patterns follow a similar trend to what was observed for residual metal catalysts in SWCNTs. Addition of NOM increased the transport of all SWCNTs primarily due to electrosteric repulsion. HiPco-D was notably more acidic than SG65-D followed by P2-D, which is similar to the transport trend. Overall, it was observed that the synthesis methods resulted in distinctive breakthrough trends, which were correlated to metal content. These

  11. Model-Based Method for Sensor Validation

    Science.gov (United States)

    Vatan, Farrokh

    2012-01-01

    Fault detection, diagnosis, and prognosis are essential tasks in the operation of autonomous spacecraft, instruments, and in situ platforms. One of NASA s key mission requirements is robust state estimation. Sensing, using a wide range of sensors and sensor fusion approaches, plays a central role in robust state estimation, and there is a need to diagnose sensor failure as well as component failure. Sensor validation can be considered to be part of the larger effort of improving reliability and safety. The standard methods for solving the sensor validation problem are based on probabilistic analysis of the system, from which the method based on Bayesian networks is most popular. Therefore, these methods can only predict the most probable faulty sensors, which are subject to the initial probabilities defined for the failures. The method developed in this work is based on a model-based approach and provides the faulty sensors (if any), which can be logically inferred from the model of the system and the sensor readings (observations). The method is also more suitable for the systems when it is hard, or even impossible, to find the probability functions of the system. The method starts by a new mathematical description of the problem and develops a very efficient and systematic algorithm for its solution. The method builds on the concepts of analytical redundant relations (ARRs).

  12. Mathematical synthesis of the thickness profile of the waveguide Lüneburg lens using the adiabatic waveguide modes method

    Science.gov (United States)

    Ayryan, Edik; Dashitsyrenov, Genin; Laneev, Evgeniy; Lovetskiy, Konstantin; Sevastianov, Leonid; Sevastianov, Anton

    2017-04-01

    The paper describes the classical and generalized Luneburg lens in the 3D and planar waveguide implementation. We demonstrate the relation between the focusing inhomogeneity of the effective refractive index of waveguide Luneburg lens and the irregularity of the waveguide layer thickness generating this inhomogeneity. For the dispersion relation of the irregular thin-film waveguide in the model of adiabatic waveguide modes we solve the problem of mathematical synthesis and computer-aided design of the thickness profile of waveguide layer for the Luneburg thin-film generalized waveguide lens with a given focal length. The calculations are carried out in specially normalized coordinates convenient for computer calculations. The solution is compared with the one obtained using the cross-sections method.

  13. Geostatistical methods applied to field model residuals

    DEFF Research Database (Denmark)

    Maule, Fox; Mosegaard, K.; Olsen, Nils

    consists of measurement errors and unmodelled signal), and is typically assumed to be uncorrelated and Gaussian distributed. We have applied geostatistical methods to analyse the residuals of the Oersted(09d/04) field model [http://www.dsri.dk/Oersted/Field_models/IGRF_2005_candidates/], which is based......The geomagnetic field varies on a variety of time- and length scales, which are only rudimentary considered in most present field models. The part of the observed field that can not be explained by a given model, the model residuals, is often considered as an estimate of the data uncertainty (which...... on 5 years of Ørsted and CHAMP data, and includes secular variation and acceleration, as well as low-degree external (magnetospheric) and induced fields. The analysis is done in order to find the statistical behaviour of the space-time structure of the residuals, as a proxy for the data covariances...

  14. Environmentally evaluated HPLC-ELSD method to monitor enzymatic synthesis of a non-ionic surfactant.

    Science.gov (United States)

    Gaber, Yasser; Akerman, Cecilia Orellana; Hatti-Kaul, Rajni

    2014-01-01

    N-Lauroyl-N-methylglucamide is a biodegradable surfactant derived from renewable resources. In an earlier study, we presented an enzymatic solvent-free method for synthesis of this compound. In the present report, the HPLC method developed to follow the reaction between lauric acid/methyl laurate and N-methyl glucamine (MEG) and its environmental assessment are described. Use of ultraviolet (UV) absorption or refractive index (RI) detectors did not allow the detection of N-methyl glucamine (MEG). With Evaporative light scattering detector ELSD, it was possible to apply a gradient elution, and detect MEG with a limit of detection, LOD = 0.12 μg. A good separation of the peaks: MEG, lauric acid, product (amide) and by-product (amide-ester) was achieved with the gradient program with a run time of 40 min. The setting of ELSD detector was optimized using methyl laurate as the analyte. LC-MS/MS was used to confirm the amide and amide-ester peaks. We evaluated the greenness of the developed method using the freely available software HPLC-Environmental Assessment Tool (HPLC-EAT) and the method got a scoring of 73 HPLC-EAT units, implying that the analytical procedure was more environmentally benign compared to some other methods reported in literature whose HPLC-EAT values scored up to 182. Use of ELSD detector allowed the detection and quantification of the substrates and the reaction products of enzymatic synthesis of the surfactant, N-lauroyl-N-methylglucamide. The developed HPLC method has acceptable environmental profile based on HPLC-EAT evaluation.

  15. Developing a TQM quality management method model

    NARCIS (Netherlands)

    Zhang, Zhihai

    1997-01-01

    From an extensive review of total quality management literature, the external and internal environment affecting an organization's quality performance and the eleven primary elements of TQM are identified. Based on the primary TQM elements, a TQM quality management method model is developed. This

  16. Railway Track Allocation: Models and Methods

    DEFF Research Database (Denmark)

    Lusby, Richard Martin; Larsen, Jesper; Ehrgott, Matthias

    2011-01-01

    Efficiently coordinating the movement of trains on a railway network is a central part of the planning process for a railway company. This paper reviews models and methods that have been proposed in the literature to assist planners in finding train routes. Since the problem of routing trains on ...

  17. Railway Track Allocation: Models and Methods

    DEFF Research Database (Denmark)

    Lusby, Richard Martin; Larsen, Jesper; Ehrgott, Matthias

    Eciently coordinating the movement of trains on a railway network is a central part of the planning process for a railway company. This paper reviews models and methods that have been proposed in the literature to assist planners in nding train routes. Since the problem of routing trains on a rai...

  18. APPROACH TO SYNTHESIS OF PASSIVE INFRARED DETECTORS BASED ON QUASI-POINT MODEL OF QUALIFIED INTRUDER

    Directory of Open Access Journals (Sweden)

    I. V. Bilizhenko

    2017-01-01

    Full Text Available Subject of Research. The paper deals with synthesis of passive infra red (PIR detectors with enhanced detection capability of qualified intruder who uses different types of detection countermeasures: the choice of specific movement direction and disguise in infrared band. Methods. We propose an approach based on quasi-point model of qualified intruder. It includes: separation of model priority parameters, formation of partial detection patterns adapted to those parameters and multi channel signal processing. Main Results. Quasi-pointmodel of qualified intruder consisting of different fragments was suggested. Power density difference was used for model parameters estimation. Criteria were formulated for detection pattern parameters choice on the basis of model parameters. Pyroelectric sensor with nine sensitive elements was applied for increasing the signal information content. Multi-channel processing with multiple partial detection patterns was proposed optimized for detection of intruder's specific movement direction. Practical Relevance. Developed functional device diagram can be realized both by hardware and software and is applicable as one of detection channels for dual technology passive infrared and microwave detectors.

  19. A Best-Evidence Synthesis of Research on Orientation and Mobility Involving Tactile Maps and Models

    Science.gov (United States)

    Wright, Tessa; Harris, Beth; Sticken, Eric

    2010-01-01

    A review of the literature from 1965 to 2008 on tactile maps and models in orientation and mobility yielded four pre-experimental and three experimental articles. The articles were analyzed via best-evidence synthesis--a combined narrative and statistical approach--allowing for recommendations for the most effective use of tactile maps and models.…

  20. Personal recovery within forensic settings--Systematic review and meta-synthesis of qualitative methods studies.

    Science.gov (United States)

    Shepherd, Andrew; Doyle, Michael; Sanders, Caroline; Shaw, Jenny

    2016-02-01

    Many mental health services now explicitly aim to support personal recovery. Are there special ethical and practical considerations for application of this model in forensic mental health services? Is there, for example, any conflict in this context between personal empowerment and risk management? Our aim was to develop a model of the personal recovery processes for people needing forensic mental health services. A systematic literature review was conducted and meta-synthesis applied to data from relevant papers. Five studies were identified through the search process and combined through meta-synthesis. Three key overarching themes were synthesised: safety and security as a necessary base for the recovery process, the dynamics of hope and social networks in supporting the recovery process and work on identity as a changing feature in the recovery process. The themes identified provide for theoretically informed and testable developments in care that could enhance the quality of recovery and rehabilitation for offender patients through explicitly enhancing personal sense of safety, understanding the patient's sense of personal identity and their social networks and transitioning between institutional and community support. Copyright © 2015 John Wiley & Sons, Ltd.

  1. Synthesis

    Directory of Open Access Journals (Sweden)

    Emel Pelit

    2016-05-01

    Full Text Available New optically active aminoalkylnaphthols were obtained by condensation of 2-naphthol, substituted aromatic and heteroaromatic aldehydes and (R-(+-1-phenylethylamine or (S-(−-1-phenylethylamine under conventional methods and ultrasonic irradiation. The enantiopure aminoalkylnaphthol derivatives were converted in ring-closure reaction with formaldehyde to the corresponding naphthoxazine derivatives.

  2. Efficient seed-mediated method for the large-scale synthesis of Au nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Waqqar; Bhatti, Arshad Saleem [COMSATS Institute of Information Technology, Department of Physics (Pakistan); Ruitenbeek, Jan M. van, E-mail: Ruitenbeek@physics.leidenuniv.nl [Leiden University, Huygens-Kamerlingh Onnes Laboratory (Netherlands)

    2017-03-15

    Seed-mediated methods are widely followed for the synthesis of Au nanorods (NRs). However, mostly dilute concentrations of the Au precursor (HAuCl{sub 4}) are used in the growth solution, which leads to a low final concentration of NRs. Attempts of increasing the concentration of NRs by simply increasing the concentration of HAuCl{sub 4}, other reagents in the growth solution and seeds lead to a faster growth kinetics which is not favourable for NR growth. Herein, we demonstrate that the increase in growth kinetics for high concentrations of reagents in growth solution can be neutralised by decreasing the pH of the solution. The synthesis of the NRs can be scaled up by using higher concentrations of reagents and adding an optimum concentration of HCl in the growth solution. The concentration of HAuCl{sub 4} in the growth solution can be increased up to 5 mM, and 10–20 times more NRs can be synthesised for the same reaction volume compared to that of the conventional seed-mediated method. We have also noticed that a cetyltrimethylammonium bromide (CTAB)-to-HAuCl{sub 4} molar ratio of 50 is sufficient for obtaining high yield of NRs.

  3. Synthesis and characterization of nano-CeO2 by detonation method

    Science.gov (United States)

    Han, Zhi-wei; Xie, Li-feng; Ni, Ou-qi; Li, Bin; Chao, Cheng; Xie, Yi-chao

    2012-04-01

    In order to study the application of detonation synthesis method in preparing nanoscale ceria(CeO2), ceria powder was synthesized by detonation method. The synthesis experiment was carried out in explosion containment vessel by initiating the emulsion explosive in which Ce(NO3)3.6H2O acted as the main oxidant. The phase composition, crystal form, appearance and microstructure of the as-synthesized products were characterized by X-ray diffraction(XRD) and Transmission Electron Microscope(TEM). The result from XRD test indicated that the nanoscale ceria belonged to cubic phase. The mean size of ceria grain was 26nm based on the calculation result according to Scherrer equation. The result from TEM test presented that the as-synthesized ceria grain was spherical by appearance, and the size was uniform. According to TEM test result, the mean size of ceria grain was between 20nm and 30nm, which coincided with calculation result perfectly.

  4. High-yield Synthesis of Multiwalled Carbon Nanotube by Mechanothermal Method

    Directory of Open Access Journals (Sweden)

    Manafi SA

    2009-01-01

    Full Text Available Abstract This study reports on the mechanothermal synthesis of multiwalled carbon nanotube (MWCNTs from elemental graphite powder. Initially, high ultra-active graphite powder can be obtained by mechanical milling under argon atmosphere. Finally, the mechanical activation product is heat-treated at 1350°C for 2–4 h under argon gas flow. After heat-treatment, active graphite powders were successfully changed into MWCNTs with high purity. The XRD analyses showed that in the duration 150 h of milling, all the raw materials were changed to the desired materials. From the broadening of the diffraction lines in the XRD patterns, it was concluded that the graphite crystallites were nanosized, and raising the milling duration resulted in the fineness of the particles and the increase of the strain. The structure and morphology of MWCNTs were investigated using scanning electron microscopy (SEM and high-resolution transmission electron microscopy (HRTEM. The yield of MWCNTs was estimated through SEM and TEM observations of the as-prepared samples was to be about 90%. Indeed, mechanothermal method is of interest for fundamental understanding and improvement of commercial synthesis of carbon nanotubes (CNTs. As a matter of fact, the method of mechanothermal guarantees the production of MWCNTs suitable for different applications.

  5. Removable Backbone Modification Method for the Chemical Synthesis of Membrane Proteins.

    Science.gov (United States)

    Li, Jia-Bin; Tang, Shan; Zheng, Ji-Shen; Tian, Chang-Lin; Liu, Lei

    2017-05-16

    Chemical synthesis can produce water-soluble globular proteins bearing specifically designed modifications. These synthetic molecules have been used to study the biological functions of proteins and to improve the pharmacological properties of protein drugs. However, the above advances notwithstanding, membrane proteins (MPs), which comprise 20-30% of all proteins in the proteomes of most eukaryotic cells, remain elusive with regard to chemical synthesis. This difficulty stems from the strong hydrophobic character of MPs, which can cause considerable handling issues during ligation, purification, and characterization steps. Considerable efforts have been made to improve the solubility of transmembrane peptides for chemical ligation. These methods can be classified into two main categories: the manipulation of external factors and chemical modification of the peptide. This Account summarizes our research advances in the development of chemical modification especially the two generations of removable backbone modification (RBM) strategy for the chemical synthesis of MPs. In the first RBM generation, we install a removable modification group at the backbone amide of Gly within the transmembrane peptides. In the second RBM generation, the RBM group can be installed into all primary amino acid residues. The second RBM strategy combines the activated intramolecular O-to-N acyl transfer reaction, in which a phenyl group remains unprotected during the coupling process, which can play a catalytic role to generate the activated phenyl ester to assist in the formation of amide. The key feature of the RBM group is its switchable stability in trifluoroacetic acid. The stability of these backbone amide N-modifications toward TFA can be modified by regulating the electronic effects of phenol groups. The free phenol group is acylated to survive the TFA deprotection step, while the acyl phenyl ester will be quantitatively hydrolyzed in a neutral aqueous solution, and the free

  6. Acceleration methods and models in Sn calculations

    International Nuclear Information System (INIS)

    Sbaffoni, M.M.; Abbate, M.J.

    1984-01-01

    In some neutron transport problems solved by the discrete ordinate method, it is relatively common to observe some particularities as, for example, negative fluxes generation, slow and insecure convergences and solution instabilities. The commonly used models for neutron flux calculation and acceleration methods included in the most used codes were analyzed, in face of their use in problems characterized by a strong upscattering effect. Some special conclusions derived from this analysis are presented as well as a new method to perform the upscattering scaling for solving the before mentioned problems in this kind of cases. This method has been included in the DOT3.5 code (two dimensional discrete ordinates radiation transport code) generating a new version of wider application. (Author) [es

  7. Synthesis and characterization of TiO2 nanoparticles by the method Pechini

    International Nuclear Information System (INIS)

    Zoccal, Joao Victor Marques; Arouca, Fabio de Oliveira; Goncalves, Jose Antonio Silveira

    2009-01-01

    In recent years, scientific research showed an increasing interest in the field of nanotechnology, resulting in several techniques for the production of nanoparticles, such as methods of chemical synthesis. Among the various existing methods, the Pechini method has been used to obtain nanoparticles of titanium dioxide (TiO 2 ). Thus, this work aims to synthesize and characterize nanoparticles of TiO 2 obtained by this method. The technique constitutes in the reaction between citric acid with titanium isopropoxide, resulting as the product the titanium citrate. With the addition of the ethylene glycol polymerization occurs, resulting in a polymeric resin. At the end of the process, the resin is calcined to remove organic matter, creating nanoparticles of TiO 2 . The resulting powders were characterized by thermogravimetric analysis (TGA) and thermal differential analysis (DTA), X-ray diffraction, absorption spectrophotometry in the infrared, method of adsorption nitrogen / helium (BET method) and scanning electron microscopy. The results obtained in the characterization techniques showed that the Pechini method is promising in obtaining nanosized TiO 2 . (author)

  8. A facile and rapid method for the black pepper leaf mediated green synthesis of silver nanoparticles and the antimicrobial study

    Science.gov (United States)

    Augustine, Robin; Kalarikkal, Nandakumar; Thomas, Sabu

    2014-10-01

    Green synthesis of nanoparticles is widely accepted due to the less toxicity in comparison with chemical methods. But there are certain drawbacks like slow formation of nanoparticles, difficulty to control particle size and shape make them less convenient. Here we report a novel cost-effective and eco-friendly method for the rapid green synthesis of silver nanoparticles using leaf extracts of Piper nigrum. Our results suggest that this method can be used for obtaining silver nanoparticles with controllable size within a few minutes. The fabricated nanoparticles possessed excellent antibacterial property against both Gram-positive and Gram-negative bacteria.

  9. ESTIMATION OF THE PROCESS OF SYNTHESIS OF MEAT BROILER THROUGH MODERN METHODS

    Directory of Open Access Journals (Sweden)

    MONICA PÂRVU

    2009-10-01

    Full Text Available In vivo experiments on broilers were conducted in order to elaborate a mathematical model for body synthesis, the experimental data being processed with Gompertz time functions and linear functions. The experiment used 166, Ross 308 day-old chicks through an experimental period of 42 days. The broilers received diets according to the growth period (1 – 14, 15 – 28, 29 – 42 days. The dietary energy and nutrient supply for group 1 (control were according to the recommendation of Ross Breeders. The birds had free access to the feed. Group 2 received 90% and group 3 received 80% of the amount of feed received by group 1; the dietary energy supply was 90% in group 4 and 80% in group 5, also related to group 1. Mathematical modelling was used to evaluate the evolution of the body chemical composition (water, protein and lipid content, starting from the protein content at hatching.

  10. Synthesis and characterization of nanosized MnZn ferrites via a modified hydrothermal method

    Science.gov (United States)

    Li, Mingling; Liu, Xiansong; Xu, Taotao; Nie, Yu; Li, Honglin; Zhang, Cong

    2017-10-01

    Nanosized MnZn ferrite particles, with narrow size distribution, regular morphology and high saturation magnetization have been synthesized via a modified hydrothermal method. This modified hydrothermal method involves a chemical co-precipitation of hydroxides under a vacuum condition using potassium hydroxide as precipitating agent, followed by a separate hydrothermal process. The microstructure and magnetic properties of the synthesized nanoparticles were investigated by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometer (VSM). The effects of different synthesis conditions (excess ratio of precipitating agent and hydrothermal reaction time) on the microstructure and magnetic properties of the as-synthesized nanoparticles were discussed. The magnetic measurements indicated that the obtained samples were superparamagnetic in nature at room temperature. Moreover, the MnZn ferrite nanoparticles with excellent magnetic performance could be synthesized at 180 °C for a short reaction time (3 h).

  11. The Synthesis Method of Automated System of Operational Planning in Low-Space Communication System Messaging

    Directory of Open Access Journals (Sweden)

    Serhii Kovbasiuk

    2017-04-01

    Full Text Available One of the reasons for the decrease of efficiency in low-speed communication systems, satellite communication, which are based on nanoplatform is a high degree of operational planning centralisation. To overcome this problem the method which carries out the distribution of tasks of communications operational planning minimizing the exchange of information between spatially remote sites, and takes into account the computing performance of software and hardware was developed. The technique is based on the use of methods of structural and parametric synthesis, simulation and statistical analysis of the results. Its use allows to obtain the optimal structure of the automated system of operational planning in low-space communication system messaging evaluation of efficiency in terms of fixed communication of information load.

  12. A method of reversible circuits synthesis based on s-maps

    Science.gov (United States)

    Skorupski, Andrzej

    2017-08-01

    This paper presents an original method to designing reversible circuits. The main problem of reversible circuits synthesis is designing optimal reversible circuits i.e. circuits with minimal gates number implementing the given reversible function. To design reversible circuits a set of gates must be chosen. The most popular library is a set called CNT (Control, NOT and Toffoli) which contains three types of gates. The method presented in this paper is based on the CNT gates. A graphical representation of the reversible function called s-maps is introduced in the paper. This representation allows to find optimal solutions. The paper is organized as follows. Section 1 recalls basic concepts of reversible logic. In Section 2 a graphical representation of the reversible functions is presented. Section 3 describes the algorithm whereby any optimal solutions of the given function could be obtained.

  13. Preparation of bimetallic nanoparticles using a facile green synthesis method and their application.

    Science.gov (United States)

    Xia, Bihua; He, Fang; Li, Lidong

    2013-04-16

    A straightforward, economically viable, and green approach for the synthesis of well-stabilized Au/Ag bimetallic nanoparticles is described; this method uses nontoxic and renewable degraded pueraria starch (DPS) as a matrix and mild reaction conditions. The DPS acted as both a reducing agent and a capping agent for the bimetallic nanoparticles. Au/Ag bimetallic nanoparticles were successfully grown within the DPS matrixes, and the bimetallic structures were characterized using various methods, including high-resolution transmission electron microscopy, energy-dispersive X-ray, and X-ray diffraction. Moreover, it was shown that these DPS-capped Au/Ag bimetallic nanoparticles could function as catalysts for the reduction of 4-nitrophenol in the presence of NaBH4 and were more effective than Au or Ag monometallic nanoparticles.

  14. Hybrid variational principles and synthesis method for finite element neutron transport calculations

    International Nuclear Information System (INIS)

    Ackroyd, R.T.; Nanneh, M.M.

    1990-01-01

    A family of hybrid variational principles is derived using a generalised least squares method. Neutron conservation is automatically satisfied for the hybrid principles employing two trial functions. No interfaces or reflection conditions need to be imposed on the independent even-parity trial function. For some hybrid principles a single trial function can be employed by relating one parity trial function to the other, using one of the parity transport equation in relaxed form. For other hybrid principles the trial functions can be employed sequentially. Synthesis of transport solutions, starting with the diffusion theory approximation, has been used as a way of reducing the scale of the computation that arises with established finite element methods for neutron transport. (author)

  15. Facile One-Pot Polyol Method for the Synthesis of Uniform Size Silver Nanowires.

    Science.gov (United States)

    Kaili, Zhang; Yongguo, Du; Shimin, Chen

    2016-01-01

    This study reports the development of a facile and efficient one-pot polyol method for the synthesis of silver nanowires. The seed and growth of silver nanowires under different reaction conditions were characterized and measured. The pertinent variables such as temperature, time, concentration and capping agent were investigated. Moreover, the effect of seeding at two different stages-initial stage and secondary stage-was studied and discussed on the size control of silver nanowires. In particular, silver nanowires with diameter less than 40 nm and length over 25 µm in a narrow distribution, was obtained through a novel method in which reaction flask was placed in a low-temperature bath after seeding for some time in the high-temperature bath. This approach may be useful for the fabrication of uniform, large aspect ratio silver nanowires for optoelectronic applications.

  16. Metal-organic frameworks: structure, properties, methods of synthesis and characterization

    International Nuclear Information System (INIS)

    Butova, V V; Soldatov, M A; Guda, A A; Lomachenko, K A; Lamberti, C

    2016-01-01

    This review deals with key methods of synthesis and characterization of metal-organic frameworks (MOFs). The modular structure affords a wide variety of MOFs with different active metal sites and organic linkers. These compounds represent a new stage of development of porous materials in which the pore size and the active site structure can be modified within wide limits. The set of experimental methods considered in this review is sufficient for studying the short-range and long-range order of the MOF crystal structure, determining the morphology of samples and elucidating the processes that occur at the active metal site in the course of chemical reactions. The interest in metal-organic frameworks results, first of all, from their numerous possible applications, ranging from gas separation and storage to chemical reactions within the pores. The bibliography includes 362 references

  17. Facile and template-free method toward chemical synthesis of polyaniline film/nanotube structures

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pei [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261; Zhu, Yisi [Materials Science Division, Argonne National Lab, Lemont Illinois 60439; Torres, Jorge [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261; Lee, Seung Hee [Department of BIN Fusion Technology, Chonbuk National University, Jeonju 561-786 Korea; Yun, Minhee [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261

    2017-09-05

    A facile and template-free method is reported to synthesize a new thin film structure: polyaniline (PANI) film/nanotubes (F/N) structure. The PANI F/N is a 100-nm thick PANI film embedded with PANI nanotubes. This well-controlled method requires no surfactant or organic acid as well as relatively low concentration of reagents. Synthesis condition studies reveal that aniline oligomers with certain structures are responsible for guiding the growth of the nanotubes. Electrical characterization also indicates that the PANI F/N possesses similar field-effect transistor characteristics to bare PANI film. With its 20% increased surface-area-to-volume (S/V) ratio contributed by surface embedded nanotubes and the excellent p-type semiconducting characteristic, PANI F/N shows clear superiority compared with bare PANI film. Such advantages guarantee the PANI F/N a promising future toward the development of ultra-high sensitivity and low-cost biosensors.

  18. Selection of Suitable Biological Method for the Synthesis of Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Muhammad Ashraf Sabri

    2016-04-01

    Full Text Available This paper aims to present a brief overview of different biosynthesis routes of silver nanoparticles (NPs, their applications and influence of the method used on the size and morphology of these nanoparticles. A detailed and comprehensive study of available biological methods, also referred to as a bottom-up approach, as well as techniques reported, have been provided with an eye for details and comparison between the techniques involving fungi, bacteria, algae and plant extracts. Plant-derived bioreduc‐ tants such as leaf, stem or root extracts of various plants are seen as suitable solutions to green synthesis of silver NPs, implementing an easy, non-toxic, clean and environmen‐ tally friendly approach. Furthermore, reports on the antimicrobial activities with the zone of inhibition for various pathogens have also been included.

  19. Ammonia synthesis and decomposition on a Ru-based catalyst modeled by first-principles

    DEFF Research Database (Denmark)

    Hellman, A.; Honkala, Johanna Karoliina; Remediakis, Ioannis

    2009-01-01

    A recently published first-principles model for the ammonia synthesis on an unpromoted Ru-based catalyst is extended to also describe ammonia decomposition. In addition, further analysis concerning trends in ammonia productivity, surface conditions during the reaction, and macro......-properties, such as apparent activation energies and reaction orders are provided. All observed trends in activity are captured by the model and the absolute value of ammonia synthesis/decomposition productivity is predicted to within a factor of 1-100 depending on the experimental conditions. Moreover it is shown: (i...

  20. Alternative methods of modeling wind generation using production costing models

    International Nuclear Information System (INIS)

    Milligan, M.R.; Pang, C.K.

    1996-08-01

    This paper examines the methods of incorporating wind generation in two production costing models: one is a load duration curve (LDC) based model and the other is a chronological-based model. These two models were used to evaluate the impacts of wind generation on two utility systems using actual collected wind data at two locations with high potential for wind generation. The results are sensitive to the selected wind data and the level of benefits of wind generation is sensitive to the load forecast. The total production cost over a year obtained by the chronological approach does not differ significantly from that of the LDC approach, though the chronological commitment of units is more realistic and more accurate. Chronological models provide the capability of answering important questions about wind resources which are difficult or impossible to address with LDC models

  1. Calibration of complex models through Bayesian evidence synthesis: a demonstration and tutorial

    Science.gov (United States)

    Jackson, Christopher; Jit, Mark; Sharples, Linda; DeAngelis, Daniela

    2016-01-01

    Summary Decision-analytic models must often be informed using data which are only indirectly related to the main model parameters. The authors outline how to implement a Bayesian synthesis of diverse sources of evidence to calibrate the parameters of a complex model. A graphical model is built to represent how observed data are generated from statistical models with unknown parameters, and how those parameters are related to quantities of interest for decision-making. This forms the basis of an algorithm to estimate a posterior probability distribution, which represents the updated state of evidence for all unknowns given all data and prior beliefs. This process calibrates the quantities of interest against data, and at the same time, propagates all parameter uncertainties to the results used for decision-making. To illustrate these methods, the authors demonstrate how a previously-developed Markov model for the progression of human papillomavirus (HPV16) infection was rebuilt in a Bayesian framework. Transition probabilities between states of disease severity are inferred indirectly from cross-sectional observations of prevalence of HPV16 and HPV16-related disease by age, cervical cancer incidence, and other published information. Previously, a discrete collection of plausible scenarios was identified, but with no further indication of which of these are more plausible. Instead, the authors derive a Bayesian posterior distribution, in which scenarios are implicitly weighted according to how well they are supported by the data. In particular, we emphasise the appropriate choice of prior distributions and checking and comparison of fitted models. PMID:23886677

  2. Real-time arbitrary view synthesis method for ultra-HD auto-stereoscopic display

    Science.gov (United States)

    Cai, Yuanfa; Sang, Xinzhu; Duo, Chen; Zhao, Tianqi; Fan, Xin; Guo, Nan; Yu, Xunbo; Yan, Binbin

    2013-08-01

    An arbitrary view synthesis method from 2D-Plus-Depth image for real-time auto-stereoscopic display is presented. Traditional methods use depth image based rendering (DIBR) technology, which is a process of synthesizing "virtual" views of a scene from still or moving images and associated per-pixel depth information. All the virtual view images are generated and then the ultimate stereo-image is synthesized. DIBR can greatly decrease the number of reference images and is flexible and efficient as the depth images are used. However it causes some problems such as the appearance of holes in the rendered image, and the occurrence of depth discontinuity on the surface of the object at virtual image plane. Here, reversed disparity shift pixel rendering is used to generate the stereo-image directly, and the target image won't generate holes. To avoid duplication of calculation and also to be able to match with any specific three-dimensional display, a selecting table is designed to pick up appropriate virtual viewpoints for auto-stereoscopic display. According to the selecting table, only sub-pixels of the appropriate virtual viewpoints are calculated, so calculation amount is independent of the number of virtual viewpoints. In addition, 3D image warping technology is used to translate depth information to parallax between virtual viewpoints and parallax, and the viewer can adjust the zero-parallax-setting-plane (ZPS) and change parallax conveniently to suit his/her personal preferences. The proposed method is implemented with OPENGL and demonstrated on a laptop computer with a 2.3 GHz Intel Core i5 CPU and NVIDA GeForce GT540m GPU. We got a frame rate 30 frames per second with 4096×2340 video. High synthesis efficiency and good stereoscopic sense can be obtained. The presented method can meet the requirements of real-time ultra-HD super multi-view auto-stereoscopic display.

  3. Mathematical methods and models in composites

    CERN Document Server

    Mantic, Vladislav

    2014-01-01

    This book provides a representative selection of the most relevant, innovative, and useful mathematical methods and models applied to the analysis and characterization of composites and their behaviour on micro-, meso-, and macroscale. It establishes the fundamentals for meaningful and accurate theoretical and computer modelling of these materials in the future. Although the book is primarily concerned with fibre-reinforced composites, which have ever-increasing applications in fields such as aerospace, many of the results presented can be applied to other kinds of composites. The topics cover

  4. Intelligent structural optimization: Concept, Model and Methods

    International Nuclear Information System (INIS)

    Lu, Dagang; Wang, Guangyuan; Peng, Zhang

    2002-01-01

    Structural optimization has many characteristics of Soft Design, and so, it is necessary to apply the experience of human experts to solving the uncertain and multidisciplinary optimization problems in large-scale and complex engineering systems. With the development of artificial intelligence (AI) and computational intelligence (CI), the theory of structural optimization is now developing into the direction of intelligent optimization. In this paper, a concept of Intelligent Structural Optimization (ISO) is proposed. And then, a design process model of ISO is put forward in which each design sub-process model are discussed. Finally, the design methods of ISO are presented

  5. Mathematical Models and Methods for Living Systems

    CERN Document Server

    Chaplain, Mark; Pugliese, Andrea

    2016-01-01

    The aim of these lecture notes is to give an introduction to several mathematical models and methods that can be used to describe the behaviour of living systems. This emerging field of application intrinsically requires the handling of phenomena occurring at different spatial scales and hence the use of multiscale methods. Modelling and simulating the mechanisms that cells use to move, self-organise and develop in tissues is not only fundamental to an understanding of embryonic development, but is also relevant in tissue engineering and in other environmental and industrial processes involving the growth and homeostasis of biological systems. Growth and organization processes are also important in many tissue degeneration and regeneration processes, such as tumour growth, tissue vascularization, heart and muscle functionality, and cardio-vascular diseases.

  6. The Schwarzschild Method for Building Galaxy Models

    Science.gov (United States)

    de Zeeuw, P. T.

    1998-09-01

    Martin Schwarzschild is most widely known as one of the towering figures of the theory of stellar evolution. However, from the early fifties onward he displayed a strong interest in dynamical astronomy, and in particular in its application to the structure of star clusters and galaxies. This resulted in a string of remarkable investigations, including the discovery of what became known as the Spitzer-Schwarzschild mechanism, the invention of the strip count method for mass determinations, the demonstration of the existence of dark matter on large scales, and the study of the nucleus of M31, based on his own Stratoscope II balloon observations. With his retirement approaching he decided to leave the field of stellar evolution, and to make his life--long hobby of stellar dynamics a full-time occupation, and to tackle the problem of self-consistent equilibria for elliptical galaxies, which by then were suspected to have a triaxial shape. Rather than following classical methods, which had trouble already in dealing with axisymmetric systems, he invented a simple numerical technique, which seeks to populate individual stellar orbits in the galaxy potential so as to reproduce the associated model density. This is now known as Schwarzschild's method. He showed by numerical calculation that most stellar orbits in a triaxial potential relevant for elliptical galaxies have two effective integrals of motion in addition to the classical energy integral, and then constructed the first ever self-consistent equilibrium model for a realistic triaxial galaxy. This provided a very strong stimulus to research in the dynamics of flattened galaxies. This talk will review how Schwarzschild's Method is used today, in problems ranging from the existence of equilibrium models as a function of shape, central cusp slope, tumbling rate, and presence of a central point mass, to modeling of individual galaxies to find stellar dynamical evidence for dark matter in extended halos, and/or massive

  7. Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis

    Directory of Open Access Journals (Sweden)

    Muhammad Faizan Shareef

    2017-10-01

    Full Text Available This paper presents the effect of a synthesis method for cobalt catalyst supported on hydrotalcite material for Fischer-Tropsch synthesis. The hydrotalcite supported cobalt (HT-Co catalysts were synthesized by co-precipitation and hydrothermal method. The prepared catalysts were characterized by using various techniques like BET (Brunauer–Emmett–Teller, SEM (Scanning Electron Microscopy, TGA (Thermal Gravimetric Analysis, XRD (X-ray diffraction spectroscopy, and FTIR (Fourier Transform Infrared Spectroscopy. Fixed bed micro reactor was used to test the catalytic activity of prepared catalysts. The catalytic testing results demonstrated the performance of hydrotalcite based cobalt catalyst in Fischer-Tropsch synthesis with high selectivity for liquid products. The effect of synthesis method on the activity and selectivity of catalyst was also discussed. Copyright © 2017 BCREC Group. All rights reserved Received: 3rd November 2016; Revised: 26th February 2017; Accepted: 9th March 2017; Available online: 27th October 2017; Published regularly: December 2017 How to Cite: Sharif, M.S., Arslan, M., Iqbal, N., Ahmad, N., Noor, T. (2017. Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis. Bulletin of Chemical Reaction Engineering & Catalysis, 12(3: 357-363 (doi:10.9767/bcrec.12.3.762.357-363

  8. Method of mechanochemical synthesis for the production of nanocrystalline Nb-Al alloys

    International Nuclear Information System (INIS)

    Portnoj, V.K.; Tret'yakov, K.V.; Logacheva, A.I.; Logunov, A.V.; Razumovskij, I.M.

    2004-01-01

    Using X-ray diffraction and DS analyses the process of solid phase synthesis on cooperative comminution of components (Nb, Al, Cr) in a planetary ball mill is investigated. Powder nanocrystalline Nb 3 Al base alloys of various compositions with simultaneous introduction of chromium are synthesized. High power milling results in block size of ∼ 20 nm. It is shown that final chromium dissolution and partial decomposition of Nb(Al) supersaturated solid solutions proceed after heating up to 1100 deg C only. With the help of doping with niobium by the method of mechanical alloying, a two-phase alloy Nb 3 Al + Nb 2 Al having been produced by arc melting, is corrected by composition and transferred to the two-phase region of Nb 3 Al + Nb(Al). It is revealed that the process of niobium aluminide phase formation during mechanochemical synthesis and the process of mechanical activation of Nb-Al system intermetallics enriched with niobium always proceed through formation of supersaturated solid solutions. The mechanism of the process is probably associated with stacking faults formation due to deformation [ru

  9. Copper Nanoparticles Mediated by Chitosan: Synthesis and Characterization via Chemical Methods

    Directory of Open Access Journals (Sweden)

    Muhammad Sani Usman

    2012-12-01

    Full Text Available Herein we report a synthesis of copper nanoparticles (Cu-NPs in chitosan (Cts media via a chemical reaction method. The nanoparticles were synthesized in an aqueous solution in the presence of Cts as stabilizer and CuSO4·5H2O precursor. The synthesis proceeded with addition of NaOH as pH moderator, ascorbic acid as antioxidant and hydrazine as the reducing agent. The characterization of the prepared NPs was done using ultraviolet-visible spectroscopy, which showed a 593 nm copper band. The Field Emission Scanning Electron Microscope (FESEM images were also observed, and found to be in agreement with the UV-Vis result, confirming the formation of metallic Cu-NPs. The mean size of the Cu-NPs was estimated to be in the range of 35–75 nm using X-ray diffraction. XRD was also used in analysis of the crystal structure of the NPs. The interaction between the chitosan and the synthesized NPs was studied using Fourier transform infrared (FT-IR spectroscopy, which showed the capping of the NPs by Cts.

  10. Synthesis of alumina powder with seeds by Pechini Method using O2 as calcination atmosphere

    International Nuclear Information System (INIS)

    Salem, R.E.P.; Guilherme, K.A.; Chinelatto, A.S.A.; Chinelatto, A. L.

    2012-01-01

    Alumina is a very investigated material due to its excellent refractory characteristics and mechanical properties. Its alpha phase, the most stable one, has a formation temperature of about 1200 ° C. Due to its high temperature of formation, many researches have been trying to reduce it through addition of seeds of alpha phase in chemical processes of synthesis. This work aims to synthesize ultrafine powders of alpha-alumina by the Pechini method with seeding, and using an O 2 atmosphere in the pre-calcination (500 ° C) and calcination (1000 ° C and 1100° C) steps. The resulting powders were characterized through X-ray diffractometry, infrared spectroscopy and scanning electron microscopy. The results were compared with samples calcined on ai. It was verified that the presence of oxygen in the calcination atmosphere favored the elimination of residual carbon from the precursor powders, forthcoming from the great amount of organic material used on the synthesis, modifying its morphology and favoring reduction of particle size. (author)

  11. Synthesis and properties of ZnS quantum dots by an oil-water interface method.

    Science.gov (United States)

    Du, Yunxing; Zhou, Xingping; Liu, Yang; Wang, Xiaqin

    2012-11-01

    Nowadays, novel synthesis routes of nanoparticles are attracting a considerable attention of relative scientists. In this work, monodispersed spherical ZnS quantum dots (QDs) were synthesized by an oil-water interface method. The as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). Typical TEM images showed that the average size of ZnS QDs was 3.3 nm. The ZnS QDs with the largest yield and UV absorbance were obtained with the mole ratio of [S2-]/[Zn2+] = 1.2/1.0 at 100 degrees C. Based on the above results and the previous outstanding work for synthesis of monodispersed inorganic nanoparticles, the formation mechanism of the monodispersed ZnS quantum dots was proposed. Additionally, UV-vis absorption and photoluminescence (PL) spectra for Mn2+ and Eu3+ doped ZnS QDs were used to investigate their optical properties. Effects of Mn2+ and Eu3+ doping ratio on their optical properties were studied. The optimized doping ratio of Mn2+ and Eu3+ was 4.0 mol.% and 5.0 mol.%, respectively.

  12. Facile Synthesis of Sub-20 nm Silver Nanowires through a Bromide-Mediated Polyol Method.

    Science.gov (United States)

    da Silva, Robson Rosa; Yang, Miaoxin; Choi, Sang-Il; Chi, Miaofang; Luo, Ming; Zhang, Chao; Li, Zhi-Yuan; Camargo, Pedro H C; Ribeiro, Sidney José Lima; Xia, Younan

    2016-08-23

    Essentially all of the Ag nanowires reported in the literature have sizes larger than 30 nm in diameter. In this article, we report a simple and robust approach to the synthesis of Ag nanowires with diameters below 20 nm and aspect ratios over 1000 using a one-pot polyol method. The Ag nanowires took a penta-twinned structure, and they could be obtained rapidly (85% of the as-obtained solid product) under atmospheric pressure. The key to the success of this synthesis is to restrain the nanowires from lateral growth by employing both Br(-) ions and poly(vinylpyrrolidone) with a high molecular weight of 1 300 000 g/mol to cap the {100} side faces, together with the use of a syringe pump to slowly introduce AgNO3 into the reaction solution. By optimizing the ratios between the capping agents and AgNO3, we were able to slow down the reduction kinetics and effectively direct the Ag nanowires to grow along the longitudinal direction only. The nanowires showed great mechanical flexibility and could be bent with acute angles without breaking. Because of their small diameters, the transverse localized surface plasmon resonance peak of the Ag nanowires could be pushed down to the ultraviolet region, below 400 nm, making them ideal conductive elements for the fabrication of touch screens, solar cells, and smart windows.

  13. Synthesis Methods of Two-Dimensional MoS2: A Brief Review

    Directory of Open Access Journals (Sweden)

    Jie Sun

    2017-07-01

    Full Text Available Molybdenum disulfide (MoS2 is one of the most important two-dimensional materials after graphene. Monolayer MoS2 has a direct bandgap (1.9 eV and is potentially suitable for post-silicon electronics. Among all atomically thin semiconductors, MoS2’s synthesis techniques are more developed. Here, we review the recent developments in the synthesis of hexagonal MoS2, where they are categorized into top-down and bottom-up approaches. Micromechanical exfoliation is convenient for beginners and basic research. Liquid phase exfoliation and solutions for chemical processes are cheap and suitable for large-scale production; yielding materials mostly in powders with different shapes, sizes and layer numbers. MoS2 films on a substrate targeting high-end nanoelectronic applications can be produced by chemical vapor deposition, compatible with the semiconductor industry. Usually, metal catalysts are unnecessary. Unlike graphene, the transfer of atomic layers is omitted. We especially emphasize the recent advances in metalorganic chemical vapor deposition and atomic layer deposition, where gaseous precursors are used. These processes grow MoS2 with the smallest building-blocks, naturally promising higher quality and controllability. Most likely, this will be an important direction in the field. Nevertheless, today none of those methods reproducibly produces MoS2 with competitive quality. There is a long way to go for MoS2 in real-life electronic device applications.

  14. Fungal synthesis of chiral phosphonic synthetic platform - Scope and limitations of the method.

    Science.gov (United States)

    Serafin-Lewańczuk, Monika; Klimek-Ochab, Magdalena; Brzezińska-Rodak, Małgorzata; Żymańczyk-Duda, Ewa

    2018-04-01

    Chiral hydroxyphosphonates due to their wide range of biological properties are industrially important chemicals. Chemical synthesis of their optical isomers is expensive, time consuming and not friendly to the environment, so biotransformations are under consideration. Among others, these compounds act as enzymes inhibitors. This makes the bioconversions of phosphonates, especially scaling experiments, hard to perform. Biocatalysis is one of the methods that can be applied in synthesis of optically pure compounds. To increase the efficiency of the process with whole cell biocatalysts, it is essential to ensure optimal reaction conditions that minimize cellular stress and can enhance the metabolic activity of cells. The present investigation focuses on the scaling up of the kinetic resolution of racemic mixture of 2-butyryloxy-2-(ethoxy-P-phenylphosphinyl)acetic acid, applying free and immobilized form of the fungal biocatalysts and two operation systems: shake flask and recirculated fixed-bed batch reactor. Protocols of effective mycelium immobilization on polyurethane foams were set for T. purpurogenus IAFB 2512, F. oxysporum, P. commune. The best results of biotransformation were obtained with the immobilized P. commune in the column recirculated fixed-bed batch reactor. The conversion reaches 56% (maximal for the kinetic process) and the enantiomeric enrichment of the isomers mixture ranges between 82 and 93% (93% for ester of R P ,R conformation). All biocatalysts exhibit S P -preference toward tested compound, what is essential because of importance of the phosphorus atom chirality for its biological activity. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Biofabrication methods for the patterned assembly and synthesis of viral nanotemplates.

    Science.gov (United States)

    Gerasopoulos, K; McCarthy, M; Banerjee, P; Fan, X; Culver, J N; Ghodssi, R

    2010-02-05

    This paper reports on novel methodologies for the patterning and templated synthesis of virus-structured nanomaterials in two- and three-dimensional microfabricated architectures using the Tobacco mosaic virus (TMV). The TMV is a high aspect ratio biological molecule which can be engineered to include amino acids with enhanced binding properties. These modifications facilitate self-assembly of the TMV onto various substrates and enable its use as a template for the synthesis of nanostructured materials. This work focuses on the combination of this bottom-up biologically inspired fabrication method with standard top-down micromachining processes that allow direct integration of the virus-structured materials into batch-fabricated devices. Photolithographic patterning of uncoated as well as nickel-coated TMV nanostructures has been achieved using a lift-off process in both solvent and mild basic solutions and their assembly onto three-dimensional polymer and silicon microstructures is demonstrated. In addition to these patterning techniques, in situ formation of metal oxide TMV coatings in patterned microfabricated environments is shown using atomic layer deposition directly on the nickel-coated viruses. The biofabrication 'process toolbox' presented in this work offers a simple and versatile alternative for the hierarchical patterning and incorporation of biotemplated nanomaterials into micro/nanofabrication schemes.

  16. Synthesis and assessment methods for an edge-alignment-free hybrid image

    Science.gov (United States)

    Sripian, Peeraya; Yamaguchi, Yasushi

    2017-07-01

    A hybrid image allows multiple image interpretations to be modulated by the viewing distance. It can be constructed on the basis of the multiscale perceptual mechanisms of the human visual system by combining the low and high spatial frequencies of two different images. The hybrid image was introduced as an experimental tool for visual recognition study in terms of spatial frequency perception. To produce a compelling hybrid image, the original hybrid image synthesis method could only use similar shapes of source images that were aligned in the edges. If any two different images can be hybrid, it would be beneficial as a new experimental tool. In addition, there is no measure for the actual perception of spatial frequency, whether a single spatial frequency or both spatial frequencies are perceived from the hybrid stimulus. This paper describes two methods for synthesizing a hybrid image from dissimilar shape images or unaligned images; this hybrid image is known as an "edge-alignment-free hybrid image." A noise-inserted method can be done by intentionally inserting and enhancing noises into the high-frequency image. With this method, the low-frequency blobs are covered with high-frequency noises when viewed up close. A color-inserted method uses complementary color gratings in the background of the high-frequency image to emphasize the high-frequency image when viewed up close, whereas the gratings disappear when viewed from far away. To ascertain that our approach successfully separates the spatial frequency at each viewing distance, we measured this property using our proposed assessment method. Our proposed method allows the experimenter to quantify the probability of perceiving both spatial frequencies and a single spatial frequency in a hybrid image. The experimental results confirmed that our proposed synthesis methods successfully hid the low-frequency image and emphasized the high-frequency image at a close viewing distance. At the same time, the

  17. Thermodynamic models to predict gas-liquid solubilities in the methanol synthesis, the methanol-higher alcohol synthesis, and the Fischer-Tropsch synthesis via gas-slurry processes

    NARCIS (Netherlands)

    Breman, B.B; Beenackers, A.A C M

    1996-01-01

    Various thermodynamic models were tested concerning their applicability to predict gas-liquid solubilities, relevant for synthesis gas conversion to methanol, higher alcohols, and hydrocarbons via gas-slurry processes. Without any parameter optimization the group contribution equation of state

  18. Model-Based Learning: A Synthesis of Theory and Research

    Science.gov (United States)

    Seel, Norbert M.

    2017-01-01

    This article provides a review of theoretical approaches to model-based learning and related research. In accordance with the definition of model-based learning as an acquisition and utilization of mental models by learners, the first section centers on mental model theory. In accordance with epistemology of modeling the issues of semantics,…

  19. Cochrane Qualitative and Implementation Methods Group guidance paper 3: methods for assessing methodological limitations, data extraction and synthesis, and confidence in synthesized qualitative findings.

    Science.gov (United States)

    Noyes, Jane; Booth, Andrew; Flemming, Kate; Garside, Ruth; Harden, Angela; Lewin, Simon; Pantoja, Tomas; Hannes, Karin; Cargo, Margaret; Thomas, James

    2017-12-13

    The Cochrane Qualitative and Implementation Methods Group develops and publishes guidance on the synthesis of qualitative and mixed-method implementation evidence. Choice of appropriate methodologies, methods, and tools is essential when developing a rigorous protocol and conducting the synthesis. Cochrane authors who conduct qualitative evidence syntheses have thus far used a small number of relatively simple methods to address similarly written questions. Cochrane has invested in methodological work to develop new tools and to encourage the production of exemplar reviews to show the value of more innovative methods that address a wider range of questions. In this paper, in the series, we report updated guidance on the selection of tools to assess methodological limitations in qualitative studies and methods to extract and synthesize qualitative evidence. We recommend application of Grades of Recommendation, Assessment, Development, and Evaluation-Confidence in the Evidence from Qualitative Reviews to assess confidence in qualitative synthesized findings. This guidance aims to support review authors to undertake a qualitative evidence synthesis that is intended to be integrated subsequently with the findings of one or more Cochrane reviews of the effects of similar interventions. The review of intervention effects may be undertaken concurrently with or separate to the qualitative evidence synthesis. We encourage further development through reflection and formal testing. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. An integrated modeling method for wind turbines

    Science.gov (United States)

    Fadaeinedjad, Roohollah

    Simulink environment to study the flicker contribution of the wind turbine in the wind-diesel system. By using a new wind power plant representation method, a large wind farm (consisting of 96 fixed speed wind turbines) is modelled to study the power quality of wind power system. The flicker contribution of wind farm is also studied with different wind turbine numbers, using the flickermeter model. Keywords. Simulink, FAST, TurbSim, AreoDyn, wind energy, doubly-fed induction generator, variable speed wind turbine, voltage sag, tower vibration, power quality, flicker, fixed speed wind turbine, wind shear, tower shadow, and yaw error.

  1. Development of a method for environmentally friendly chemical peptide synthesis in water using water-dispersible amino acid nanoparticles

    Directory of Open Access Journals (Sweden)

    Fukumori Yoshinobu

    2011-08-01

    Full Text Available Abstract Due to the vast importance of peptides in biological processes, there is an escalating need for synthetic peptides to be used in a wide variety of applications. However, the consumption of organic solvent is extremely large in chemical peptide syntheses because of the multiple condensation steps in organic solvents. That is, the current synthesis method is not environmentally friendly. From the viewpoint of green sustainable chemistry, we focused on developing an organic solvent-free synthetic method using water, an environmentally friendly solvent. Here we described in-water synthesis technology using water-dispersible protected amino acids.

  2. Simple and an efficient method for the synthesis of 1-[2-dimethylamino-1-(4-methoxy-phenyl)-ethyl]-cyclohexanol hydrochloride: (+/-) venlafaxine racemic mixtures.

    Science.gov (United States)

    Basappa; Kavitha, C V; Rangappa, K S

    2004-06-21

    A novel synthetic method was developed for the synthesis of venlafaxine using inexpensive reagents. An improvement in the method, in the yield was achieved for the conversion of the venlafaxine. This is an improved version, simple and efficient method for the large-scale synthesis of venlafaxine.

  3. A Method to Test Model Calibration Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Judkoff, Ron; Polly, Ben; Neymark, Joel

    2016-08-26

    This paper describes a method for testing model calibration techniques. Calibration is commonly used in conjunction with energy retrofit audit models. An audit is conducted to gather information about the building needed to assemble an input file for a building energy modeling tool. A calibration technique is used to reconcile model predictions with utility data, and then the 'calibrated model' is used to predict energy savings from a variety of retrofit measures and combinations thereof. Current standards and guidelines such as BPI-2400 and ASHRAE-14 set criteria for 'goodness of fit' and assume that if the criteria are met, then the calibration technique is acceptable. While it is logical to use the actual performance data of the building to tune the model, it is not certain that a good fit will result in a model that better predicts post-retrofit energy savings. Therefore, the basic idea here is that the simulation program (intended for use with the calibration technique) is used to generate surrogate utility bill data and retrofit energy savings data against which the calibration technique can be tested. This provides three figures of merit for testing a calibration technique, 1) accuracy of the post-retrofit energy savings prediction, 2) closure on the 'true' input parameter values, and 3) goodness of fit to the utility bill data. The paper will also discuss the pros and cons of using this synthetic surrogate data approach versus trying to use real data sets of actual buildings.

  4. Synthesis of cerium oxide (CeO{sub 2}) nanoparticles using simple CO-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Farahmandjou, M.; Zarinkamar, M.; Firoozabadi, T. P., E-mail: farahamndjou@iauvaramin.ac.ir [Islamis Azad University, Varamin-Phisva Branch, Department of Physics, Varamin (Iran, Islamic Republic of)

    2016-11-01

    Synthesis of cerium oxide (CeO{sub 2}) nanoparticles was studied by new and simple co-precipitation method. The cerium oxide nanoparticles were synthesized using cerium nitrate and potassium carbonate precursors. Their physicochemical properties were characterized by high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (Sem), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (Ftir) and UV-Vis spectrophotometer. XRD pattern showed the cubic structure of the cerium oxide nanoparticles. The average particle size of CeO{sub 2} was around 20 nm as estimated by XRD technique and direct HRTEM observations. The surface morphological studies from Sem and Tem depicted spherical particles with formation of clusters. The sharp peaks in Ftir spectrum determined the existence of CeO{sub 2} stretching mode and the absorbance peak of UV-Vis spectrum showed the bandgap energy of 3.26 eV. (Author)

  5. Methods for Improving Enzymatic Trans-glycosylation for Synthesis of Human Milk Oligosaccharide Biomimetics

    DEFF Research Database (Denmark)

    Zeuner, Birgitte; Jers, Carsten; Mikkelsen, Jørn Dalgaard

    2014-01-01

    , enzyme recycling, and/or the use of cosolvents may significantly improve trans-glycosylation and biocatalytic productivity of the enzymatic reactions. Protein engineering is also a promising technique for obtaining high trans-glycosylation yields, and proof-of-concept for reversing sialidase activity...... optimization to promote “reverse” catalysis with glycosidases is currently preferred over the use of glycosyl transferases. Numerous methods exist for minimizing the undesirable glycosidase-catalyzed hydrolysis and for improving the trans-glycosylation yields. This review provides an overview of the approaches...... and data available concerning optimization of enzymatic trans-glycosylation for novel synthesis of complex bioactive carbohydrates using sialidases, α-l-fucosidases, and β-galactosidases as examples. The use of an adequately high acceptor/donor ratio, reaction time control, continuous product removal...

  6. The review of various synthesis methods of barium titanate with the enhanced dielectric properties

    International Nuclear Information System (INIS)

    More, S. P.; Topare, R. J.

    2016-01-01

    The Barium Titanate is a very well known dielectric ceramic belongs to perovskite structure. It has very wide applications in the field of electronic, electro ceramic, electromechanical and electro-optical applications. Barium Titanate has very high dielectric constant as well as low dielectric loss. Substituted dielectrics are one of the most important technological compounds in modern electro ceramics. Its electrical properties can be tuned flexibly by a simple substitution technique. This has encouraged researchers to select a typical cation to be substituted at cationic sites. In the present paper, the review of various synthesis methods of Barium Titanate compound with the effect of different dopants, the grain size on the dielectric properties at various temperatures is discussed.

  7. Synthesis and characterization of NiO nanoparticles by Pechini method

    International Nuclear Information System (INIS)

    Nascimento, A.; Ribeiro, M.A.; Costa, A.C.F.M.; Gama, L.; Bernardi, M.I.B.

    2009-01-01

    In recent years, ultrafine magnetic particles of NiO have attracting the attention because of its unknown behavior, enormous scientific potential and technological application. Some of its more important properties are accented magnetic moments, double dynamic exchange, quantization of wave of spin and etc. In this context, this work has for objective to synthesize and to characterize nanoparticles of NiO for the Pechini method. The powder was analyzed by X-rays diffraction. The results of scanning electron microscopy, adsorption of nitrogen. The analysis of X-rays diffraction of the sample showed single-phase peaks of NiO, with crystallite size close to 38 nm. The surface area was 6.44 m 2 /g. The image from scanning electron microscopy shows soft homogeneous agglomerates. The Pechini synthesis was efficient in the production of powders of NiO nano metrics and single-phase. (author)

  8. Synthesis and Characterization of Polyethylene Glycol Mediated Silver Nanoparticles by the Green Method

    Directory of Open Access Journals (Sweden)

    Yadollah Abdollahi

    2012-05-01

    Full Text Available The roles of green chemistry in nanotechnology and nanoscience fields are very significant in the synthesis of diverse nanomaterials. Herein, we report a green chemistry method for synthesized colloidal silver nanoparticles (Ag NPs in polymeric media. The colloidal Ag NPs were synthesized in an aqueous solution using silver nitrate, polyethylene glycol (PEG, and β-d-glucose as a silver precursor, stabilizer, and reducing agent, respectively. The properties of synthesized colloidal Ag NPs were studied at different reaction times. The ultraviolet-visible spectra were in excellent agreement with the obtained nanostructure studies performed by transmission electron microscopy (TEM and their size distributions. The Ag NPs were characterized by utilizing X-ray diffraction (XRD, zeta potential measurements and Fourier transform infrared (FT-IR. The use of green chemistry reagents, such as glucose, provides green and economic features to this work.

  9. Synthesis and Characterization of Polyethylene Glycol Mediated Silver Nanoparticles by the Green Method

    Science.gov (United States)

    Shameli, Kamyar; Ahmad, Mansor Bin; Jazayeri, Seyed Davoud; Sedaghat, Sajjad; Shabanzadeh, Parvaneh; Jahangirian, Hossein; Mahdavi, Mahnaz; Abdollahi, Yadollah

    2012-01-01

    The roles of green chemistry in nanotechnology and nanoscience fields are very significant in the synthesis of diverse nanomaterials. Herein, we report a green chemistry method for synthesized colloidal silver nanoparticles (Ag NPs) in polymeric media. The colloidal Ag NPs were synthesized in an aqueous solution using silver nitrate, polyethylene glycol (PEG), and β-D-glucose as a silver precursor, stabilizer, and reducing agent, respectively. The properties of synthesized colloidal Ag NPs were studied at different reaction times. The ultraviolet-visible spectra were in excellent agreement with the obtained nanostructure studies performed by transmission electron microscopy (TEM) and their size distributions. The Ag NPs were characterized by utilizing X-ray diffraction (XRD), zeta potential measurements and Fourier transform infrared (FT-IR). The use of green chemistry reagents, such as glucose, provides green and economic features to this work. PMID:22837654

  10. Synthesis methods, microscopy characterization and device integration of nanoscale metal oxide semiconductors for gas sensing.

    Science.gov (United States)

    Vander Wal, Randy L; Berger, Gordon M; Kulis, Michael J; Hunter, Gary W; Xu, Jennifer C; Evans, Laura

    2009-01-01

    A comparison is made between SnO(2), ZnO, and TiO(2) single-crystal nanowires and SnO(2) polycrystalline nanofibers for gas sensing. Both nanostructures possess a one-dimensional morphology. Different synthesis methods are used to produce these materials: thermal evaporation-condensation (TEC), controlled oxidation, and electrospinning. Advantages and limitations of each technique are listed. Practical issues associated with harvesting, purification, and integration of these materials into sensing devices are detailed. For comparison to the nascent form, these sensing materials are surface coated with Pd and Pt nanoparticles. Gas sensing tests, with respect to H(2), are conducted at ambient and elevated temperatures. Comparative normalized responses and time constants for the catalyst and noncatalyst systems provide a basis for identification of the superior metal-oxide nanostructure and catalyst combination. With temperature-dependent data, Arrhenius analyses are made to determine activation energies for the catalyst-assisted systems.

  11. Discovery of Antibiotics-derived Polymers for Gene Delivery using Combinatorial Synthesis and Cheminformatics Modeling

    Science.gov (United States)

    Potta, Thrimoorthy; Zhen, Zhuo; Grandhi, Taraka Sai Pavan; Christensen, Matthew D.; Ramos, James; Breneman, Curt M.; Rege, Kaushal

    2014-01-01

    We describe the combinatorial synthesis and cheminformatics modeling of aminoglycoside antibiotics-derived polymers for transgene delivery and expression. Fifty-six polymers were synthesized by polymerizing aminoglycosides with diglycidyl ether cross-linkers. Parallel screening resulted in identification of several lead polymers that resulted in high transgene expression levels in cells. The role of polymer physicochemical properties in determining efficacy of transgene expression was investigated using Quantitative Structure-Activity Relationship (QSAR) cheminformatics models based on Support Vector Regression (SVR) and ‘building block’ polymer structures. The QSAR model exhibited high predictive ability, and investigation of descriptors in the model, using molecular visualization and correlation plots, indicated that physicochemical attributes related to both, aminoglycosides and diglycidyl ethers facilitated transgene expression. This work synergistically combines combinatorial synthesis and parallel screening with cheminformatics-based QSAR models for discovery and physicochemical elucidation of effective antibiotics-derived polymers for transgene delivery in medicine and biotechnology. PMID:24331709

  12. Discovery of antibiotics-derived polymers for gene delivery using combinatorial synthesis and cheminformatics modeling.

    Science.gov (United States)

    Potta, Thrimoorthy; Zhen, Zhuo; Grandhi, Taraka Sai Pavan; Christensen, Matthew D; Ramos, James; Breneman, Curt M; Rege, Kaushal

    2014-02-01

    We describe the combinatorial synthesis and cheminformatics modeling of aminoglycoside antibiotics-derived polymers for transgene delivery and expression. Fifty-six polymers were synthesized by polymerizing aminoglycosides with diglycidyl ether cross-linkers. Parallel screening resulted in identification of several lead polymers that resulted in high transgene expression levels in cells. The role of polymer physicochemical properties in determining efficacy of transgene expression was investigated using Quantitative Structure-Activity Relationship (QSAR) cheminformatics models based on Support Vector Regression (SVR) and 'building block' polymer structures. The QSAR model exhibited high predictive ability, and investigation of descriptors in the model, using molecular visualization and correlation plots, indicated that physicochemical attributes related to both, aminoglycosides and diglycidyl ethers facilitated transgene expression. This work synergistically combines combinatorial synthesis and parallel screening with cheminformatics-based QSAR models for discovery and physicochemical elucidation of effective antibiotics-derived polymers for transgene delivery in medicine and biotechnology. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Cu/ZnO aggregates in siliceous mesoporous matrices : development of a new model methanol synthesis catalyst

    OpenAIRE

    Berg, Maurits W. E. van den; Polarz, Sebastian; Tkachenko, Olga P.; Klementiev, Konstantin V.; Bandyopadhyay, Mahuya; Khodeir, Lamma; Gies, Hermann; Muhler, Martin; Grünert, Wolfgang

    2006-01-01

    Copper and zinc were introduced into mesoporous siliceous matrices with the goal of obtaining model methanol synthesis catalysts with intense interaction between copper and the ZnO promoter. The preparation methods included various aqueous routes starting from acetate solutions (into MCM-48) and a route involving an organometallic step thermolysis of a liquid heterocubane of Zn4O4 type ([CH3ZnOCH2CH2OCH3]4) in a wormhole-type silica of 5 nm average pore size followed by aqueous Cu (nitrate) i...

  14. GALEV evolutionary synthesis models – I. Code, input physics and web

    NARCIS (Netherlands)

    Kotulla, R.; Fritze, U.; Weilbacher, P.; Anders, P.

    2009-01-01

    GALEV (GALaxy EVolution) evolutionary synthesis models describe the evolution of stellar populations in general, of star clusters as well as of galaxies, both in terms of resolved stellar populations and of integrated light properties over cosmological time-scales of ≥13 Gyr from the onset of star

  15. Synthesis of semantic modelling and risk analysis methodology applied to animal welfare

    NARCIS (Netherlands)

    Bracke, M.B.M.; Edwards, S.A.; Metz, J.H.M.; Noordhuizen, J.P.T.M.; Algers, B.

    2008-01-01

    Decision-making on animal welfare issues requires a synthesis of information. For the assessment of farm animal welfare based on scientific information collected in a database, a methodology called `semantic modelling¿ has been developed. To date, however, this methodology has not been generally

  16. Absorption tuning of the green fluorescent protein chromophore: synthesis and studies of model compounds

    DEFF Research Database (Denmark)

    Brøndsted Nielsen, Mogens; Andersen, Lars Henrik; Rinza, Tomás Rocha

    2011-01-01

    The green fluorescent protein (GFP) chromophore is a heterocyclic compound containing a p-hydroxybenzylidine attached to an imidazol-5(4H)-one ring. This review covers the synthesis of a variety of model systems for elucidating the intrinsic optical properties of the chromophore in the gas phase...

  17. A discourse model of affect for text-to-speech synthesis

    CSIR Research Space (South Africa)

    Schlunz, GI

    2013-12-01

    Full Text Available This paper introduces a model of affect to improve prosody in text-to-speech synthesis. It operates on the discourse level of text to predict the underlying linguistic factors that contribute towards emotional appraisal, rather than any particular...

  18. Synthesis, Modelling and Evaluation of Pretreatment Technologies for Biofuels Production Systems

    DEFF Research Database (Denmark)

    Rodrigues Gurgel da Silva, Andrè

    2017-01-01

    was developed for process synthesis of a second generation bioethanol production process. The methodology was used to generate a set of alternatives for organosolv and ammonia fiber explosion (AFEX) pretreatment methods, and to evaluate hotspots in the systems for enhanced and more integrated setups....

  19. Synthesis of graphene on nickel films by CVD method using methane

    International Nuclear Information System (INIS)

    Castro, Manuela O. de; Liebold-Ribeiro, Yvonne; Barros, Eduardo B.; Salomao, Francisco C.C.; Mendes Filho, Josue; Souza Filho, Antonio G.; Chesman, Carlos

    2011-01-01

    Full text: Nanomaterials have opened up many possibilities for groundbreaking innovations in various technologies of modern society. One key example is graphene, which is composed of one-atom-thick sheet of sp2-bonded carbon atoms, arranged in a hexagonal symmetry. However, real world applications of graphene require well-established and large synthesis techniques. The so-called Chemical Vapor Deposition (CVD) is one of the most promising method for synthesizing graphene. The general idea of this technique is to dissolve carbon atoms inside a transition metal melt at a certain temperature, then allowing the dissolved carbon to precipitate at lower temperatures as single layer graphene (SLG). In the present work, we used the CVD method and methane gas as carbon source for the synthesis of graphene on silicon (Si) substrates (300nm thermal oxide) covered with sputtered nickel (Ni) films as catalyst. In order to achieve large-area and defect-free graphene sheets the influence of the different growth parameters (growth temperature and time, gas flow of methane, film thickness and grain size of Ni) on quality and quantity of graphene growth were studied. The obtained graphene films were transferred to a silicon substrate by the polymer coating process, using polymethyl-methacrylate (PMMA) as coating. In order to characterize the transferred graphene we used Scanning Electron Microscopy (SEM), Raman Spectroscopy, Optical Microscopy and Atomic Force Microscopy (AFM). The results show the influence of CVD process parameters on the quality and quantity of graphene growth in our experimental conditions. Acknowledgments: The authors thank Brazilian agencies CNPq and FUNCAP for financial support and Alfonso Reina (MIT, USA) for helpful discussions. (author)

  20. Synthesis of Polysyllabic Sequences of Thai Tones Using a Generative Model of Fundamental Frequency Contours

    Science.gov (United States)

    Seresangtakul, Pusadee; Takara, Tomio

    In this paper, the distinctive tones of Thai in running speech are studied. We present rules to synthesize F0 contours of Thai tones in running speech by using the generative model of F0 contours. Along with our method, the pitch contours of Thai polysyllabic words, both disyllabic and trisyllabic words, were analyzed. The coarticulation effect of Thai tones in running speech were found. Based on the analysis of the polysyllabic words using this model, rules are derived and applied to synthesize Thai polysyllabic tone sequences. We performed listening tests to evaluate intelligibility of the rules for Thai tones generation. The average intelligibility scores became 98.8%, and 96.6% for disyllabic and trisyllabic words, respectively. From these result, the rule of the tones' generation was shown to be effective. Furthermore, we constructed the connecting rules to synthesize suprasegmental F0 contours using the trisyllable training rules' parameters. The parameters of the first, the third, and the second syllables were selected and assigned to the initial, the ending, and the remaining syllables in a sentence, respectively. Even such a simple rule, the synthesized phrases/senetences were completely identified in listening tests. The MOSs (Mean Opinion Score) was 3.50 while the original and analysis/synthesis samples were 4.82 and 3.59, respectively.

  1. ACTIVE AND PARTICIPATORY METHODS IN BIOLOGY: MODELING

    Directory of Open Access Journals (Sweden)

    Brînduşa-Antonela SBÎRCEA

    2011-01-01

    Full Text Available By using active and participatory methods it is hoped that pupils will not only come to a deeper understanding of the issues involved, but also that their motivation will be heightened. Pupil involvement in their learning is essential. Moreover, by using a variety of teaching techniques, we can help students make sense of the world in different ways, increasing the likelihood that they will develop a conceptual understanding. The teacher must be a good facilitator, monitoring and supporting group dynamics. Modeling is an instructional strategy in which the teacher demonstrates a new concept or approach to learning and pupils learn by observing. In the teaching of biology the didactic materials are fundamental tools in the teaching-learning process. Reading about scientific concepts or having a teacher explain them is not enough. Research has shown that modeling can be used across disciplines and in all grade and ability level classrooms. Using this type of instruction, teachers encourage learning.

  2. Surface physics theoretical models and experimental methods

    CERN Document Server

    Mamonova, Marina V; Prudnikova, I A

    2016-01-01

    The demands of production, such as thin films in microelectronics, rely on consideration of factors influencing the interaction of dissimilar materials that make contact with their surfaces. Bond formation between surface layers of dissimilar condensed solids-termed adhesion-depends on the nature of the contacting bodies. Thus, it is necessary to determine the characteristics of adhesion interaction of different materials from both applied and fundamental perspectives of surface phenomena. Given the difficulty in obtaining reliable experimental values of the adhesion strength of coatings, the theoretical approach to determining adhesion characteristics becomes more important. Surface Physics: Theoretical Models and Experimental Methods presents straightforward and efficient approaches and methods developed by the authors that enable the calculation of surface and adhesion characteristics for a wide range of materials: metals, alloys, semiconductors, and complex compounds. The authors compare results from the ...

  3. Wind turbine noise modeling : a comparison of modeling methods

    International Nuclear Information System (INIS)

    Wang, L.; Strasser, A.

    2009-01-01

    All wind turbine arrays must undergo a noise impact assessment. DataKustik GmbH developed the Computer Aided Noise Abatement (Cadna/A) modeling software for calculating noise propagation to meet accepted protocols and international standards such as CONCAWE and ISO 9613 standards. The developer of Cadna/A, recommended the following 3 models for simulating wind turbine noise. These include a disk of point sources; a ring of point sources located at the tip of each blade; and a point source located at the top of the wind turbine tower hub. This paper presented an analytical comparison of the 3 models used for a typical wind turbine with a hub tower containing 3 propeller blades, a drive-train and top-mounted generator, as well as a representative wind farm, using Cadna/A. AUC, ISO and IEC criteria requirements for the meteorological input with Cadna/A for wind farm noise were also discussed. The noise predicting modelling approach was as follows: the simplest model, positioning a single point source at the top of the hub, can be used to predict sound levels for a typical wind turbine if receptors are located 250 m from the hub; a-weighted sound power levels of a wind turbine at cut-in and cut-off wind speed should be used in the models; 20 by 20 or 50 by 50 meter terrain parameters are suitable for large wind farm modeling; and ISO 9613-2 methods are recommended to predict wind farm noise with various metrological inputs based on local conditions. The study showed that the predicted sound level differences of the 3 wind turbine models using Cadna/A are less than 0.2 dB at receptors located greater than 250 m from the wind turbine hub, which fall within the accuracy range of the calculation method. All 3 models of wind turbine noise meet ISO9613-2 standards for noise prediction using Cadna/A. However, the single point source model was found to be the most efficient in terms of modeling run-time among the 3 models. 7 refs., 3 tabs., 15 figs.

  4. Statistical Models and Methods for Lifetime Data

    CERN Document Server

    Lawless, Jerald F

    2011-01-01

    Praise for the First Edition"An indispensable addition to any serious collection on lifetime data analysis and . . . a valuable contribution to the statistical literature. Highly recommended . . ."-Choice"This is an important book, which will appeal to statisticians working on survival analysis problems."-Biometrics"A thorough, unified treatment of statistical models and methods used in the analysis of lifetime data . . . this is a highly competent and agreeable statistical textbook."-Statistics in MedicineThe statistical analysis of lifetime or response time data is a key tool in engineering,

  5. Mechanics, Models and Methods in Civil Engineering

    CERN Document Server

    Maceri, Franco

    2012-01-01

    „Mechanics, Models and Methods in Civil Engineering” collects leading papers dealing with actual Civil Engineering problems. The approach is in the line of the Italian-French school and therefore deeply couples mechanics and mathematics creating new predictive theories, enhancing clarity in understanding, and improving effectiveness in applications. The authors of the contributions collected here belong to the Lagrange Laboratory, an European Research Network active since many years. This book will be of a major interest for the reader aware of modern Civil Engineering.

  6. The forward tracking, an optical model method

    CERN Document Server

    Benayoun, M

    2002-01-01

    This Note describes the so-called Forward Tracking, and the underlying optical model, developed in the context of LHCb-Light studies. Starting from Velo tracks, cheated or found by real pattern recognition, the tracks are found in the ST1-3 chambers after the magnet. The main ingredient to the method is a parameterisation of the track in the ST1-3 region, based on the Velo track parameters and an X seed in one ST station. Performance with the LHCb-Minus and LHCb-Light setups is given.

  7. Experimental modeling methods in Industrial Engineering

    Directory of Open Access Journals (Sweden)

    Peter Trebuňa

    2009-03-01

    Full Text Available Dynamic approaches to a management system of the present industrial practice, forcing businesses to address management issues in-house continuous improvement of production and non-production processes. Experience has repeatedly demonstrated the need for a system approach not only in analysis but also in the planning and actual implementation of these processes. Therefore, the contribution is focused on the description of the modeling in industrial practice by a system approach, in order to avoid erroneous application of the decision to the implementation phase, and thus prevent any longer applying methods "attempt - fallacy".

  8. Finite element modeling methods for photonics

    CERN Document Server

    Rahman, B M Azizur

    2013-01-01

    The term photonics can be used loosely to refer to a vast array of components, devices, and technologies that in some way involve manipulation of light. One of the most powerful numerical approaches available to engineers developing photonic components and devices is the Finite Element Method (FEM), which can be used to model and simulate such components/devices and analyze how they will behave in response to various outside influences. This resource provides a comprehensive description of the formulation and applications of FEM in photonics applications ranging from telecommunications, astron

  9. Model for the mechanism and regulation of chitosan synthesis in Mucor rouxii

    International Nuclear Information System (INIS)

    Davis, L.L.; Bartnicki-Garcia, S.

    1984-01-01

    The cell walls of mucoraceous fungi are characterized by the joint occurrence of chitosan and chitin, the β-1,4-linked polysaccharides of G1cN and G1cNAc, respectively. It has been proposed that chitosan is made from chitin by enzymatic deacetylation, but the evidence is inconclusive since the deacetylase isolated from Mucor rouxii is effective against glycol chitin, but not against genuine chitin; consequently, chitosan synthesis in vitro was not achieved. The authors discovered that the same deacetylase can deacetylate chitin efficiently if it is allowed to act on chitin chains as they are being formed; i.e. the simultaneous presence and operation of chitin synthetase and chitin deacetylase is required for chitosan synthesis. Subsequent studies on the effect of digitonin on chitosan synthesis were the basis for a model the authors have developed for the regulation of chitosan and chitin syntheses in vivo

  10. Asia-MIP: Multi Model-data Synthesis of Terrestrial Carbon Cycles in Asia

    Science.gov (United States)

    Ichii, K.; Kondo, M.; Ito, A.; Kang, M.; Sasai, T.; SATO, H.; Ueyama, M.; Kobayashi, H.; Saigusa, N.; Kim, J.

    2013-12-01

    Asia, which is characterized by monsoon climate and intense human activities, is one of the prominent understudied regions in terms of terrestrial carbon budgets and mechanisms of carbon exchange. To better understand terrestrial carbon cycle in Asia, we initiated multi-model and data intercomparison project in Asia (Asia-MIP). We analyzed outputs from multiple approaches: satellite-based observations (AVHRR and MODIS) and related products, empirically upscaled estimations (Support Vector Regression) using eddy-covariance observation network in Asia (AsiaFlux, CarboEastAsia, FLUXNET), ~10 terrestrial biosphere models (e.g. BEAMS, Biome-BGC, LPJ, SEIB-DGVM, TRIFFID, VISIT models), and atmospheric inversion analysis (e.g. TransCom models). We focused on the two difference temporal coverage: long-term (30 years; 1982-2011) and decadal (10 years; 2001-2010; data intensive period) scales. The regions of covering Siberia, Far East Asia, East Asia, Southeast Asia and South Asia (60-80E, 10S-80N), was analyzed in this study for assessing the magnitudes, interannual variability, and key driving factors of carbon cycles. We will report the progress of synthesis effort to quantify terrestrial carbon budget in Asia. First, we analyzed the recent trends in Gross Primary Productivities (GPP) using satellite-based observation (AVHRR) and multiple terrestrial biosphere models. We found both model outputs and satellite-based observation consistently show an increasing trend in GPP in most of the regions in Asia. Mechanisms of the GPP increase were analyzed using models, and changes in temperature and precipitation play dominant roles in GPP increase in boreal and temperate regions, whereas changes in atmospheric CO2 and precipitation are important in tropical regions. However, their relative contributions were different. Second, in the decadal analysis (2001-2010), we found that the negative GPP and carbon uptake anomalies in 2003 summer in Far East Asia is one of the largest

  11. Simulating Cellulose Structure, Properties, Thermodynamics, Synthesis, and Deconstruction with Atomistic and Coarse-Grain Models

    Energy Technology Data Exchange (ETDEWEB)

    Crowley, M. F.; Matthews, J.; Beckham, G.; Bomble, Y.; Hynninen, A. P.; Ciesielski, P. F.

    2012-01-01

    Cellulose is still a mysterious polymer in many ways: structure of microfibrils, thermodynamics of synthesis and degradation, and interactions with other plant cell wall components. Our aim is to uncover the details and mechanisms of cellulose digestion and synthesis. We report the details of the structure of cellulose 1-beta under several temperature conditions and report here the results of these studies and connections to experimental measurements and the measurement in-silico the free energy of decrystallization of several morphologies of cellulose. In spatially large modeling, we show the most recent work of mapping atomistic and coarse-grain models into tomographic images of cellulose and extreme coarse-grain modeling of interactions of large cellulase complexes with microfibrils. We discuss the difficulties of modeling cellulose and suggest future work both experimental and theoretical to increase our understanding of cellulose and our ability to use it as a raw material for fuels and materials.

  12. Ammonia synthesis and decomposition on a Ru-based catalyst modeled by first-principles

    Science.gov (United States)

    Hellman, A.; Honkala, K.; Remediakis, I. N.; Logadóttir, Á.; Carlsson, A.; Dahl, S.; Christensen, C. H.; Nørskov, J. K.

    2009-06-01

    A recently published first-principles model for the ammonia synthesis on an unpromoted Ru-based catalyst is extended to also describe ammonia decomposition. In addition, further analysis concerning trends in ammonia productivity, surface conditions during the reaction, and macro-properties, such as apparent activation energies and reaction orders are provided. All observed trends in activity are captured by the model and the absolute value of ammonia synthesis/decomposition productivity is predicted to within a factor of 1-100 depending on the experimental conditions. Moreover it is shown: (i) that small changes in the relative adsorption potential energies are sufficient to get a quantitative agreement between theory and experiment ( Appendix A) and (ii) that it is possible to reproduce results from the first-principles model by a simple micro-kinetic model ( Appendix B).

  13. Convenient, rapid synthesis of silver nanocubes and nanowires via a microwave-assisted polyol method

    Science.gov (United States)

    Chen, Dapeng; Qiao, Xueliang; Qiu, Xiaolin; Chen, Jianguo; Jiang, Renzhi

    2010-01-01

    Silver nanostructures have been synthesized via a microwave-assisted polyol method by adding sodium sulfide (Na2S) into the solution. An interesting morphology evolution can be observed by adjusting the concentration of Na2S and the heating power. It is found that the ideal concentration of Na2S is 31.25-500 µM for the fast reduction of Ag+ at 300 W under optimal conditions for producing monodispersed silver nanocubes. When the heating power is increased to 400 W, 62.5-250 µM is the ideal concentration of Na2S for the synthesis of silver nanocubes. On increasing the concentration of Na2S (>500 µM), a mixture of silver nanowires, nanocubes, bipyramids, and irregular/quasispherical particles is synthesized at 300 and 400 W. In particular, an increase in the concentration of Na2S to 750 µM at 400 W leads to the production of a quantity of silver nanowires. In addition, silver nanocubes with controllable sizes can be obtained by changing the concentration of Na2S and the heating power. Compared to traditional wet-chemical methods, this method has the advantage of a marked decrease in reaction time to 3.5 min. Finally, our work provides a simple strategy for fabricating silver nanostructures with controllable morphologies and sizes.

  14. Convenient, rapid synthesis of silver nanocubes and nanowires via a microwave-assisted polyol method

    Energy Technology Data Exchange (ETDEWEB)

    Chen Dapeng; Qiao Xueliang; Chen Jianguo; Jiang Renzhi [State Key Laboratory of Plastic Forming Simulation and Die and Mold Technology, Huazhong University of Science and Technology, Wuhan, 430074, Hubei (China); Qiu Xiaolin, E-mail: dpchenhust@yahoo.com.cn [Nanomaterials Research Center, Nanchang Institute of Technology, Nanchang, 330013, Jiangxi (China)

    2010-01-15

    Silver nanostructures have been synthesized via a microwave-assisted polyol method by adding sodium sulfide (Na{sub 2}S) into the solution. An interesting morphology evolution can be observed by adjusting the concentration of Na{sub 2}S and the heating power. It is found that the ideal concentration of Na{sub 2}S is 31.25-500 {mu}M for the fast reduction of Ag{sup +} at 300 W under optimal conditions for producing monodispersed silver nanocubes. When the heating power is increased to 400 W, 62.5-250 {mu}M is the ideal concentration of Na{sub 2}S for the synthesis of silver nanocubes. On increasing the concentration of Na{sub 2}S (>500 {mu}M), a mixture of silver nanowires, nanocubes, bipyramids, and irregular/quasispherical particles is synthesized at 300 and 400 W. In particular, an increase in the concentration of Na{sub 2}S to 750 {mu}M at 400 W leads to the production of a quantity of silver nanowires. In addition, silver nanocubes with controllable sizes can be obtained by changing the concentration of Na{sub 2}S and the heating power. Compared to traditional wet-chemical methods, this method has the advantage of a marked decrease in reaction time to 3.5 min. Finally, our work provides a simple strategy for fabricating silver nanostructures with controllable morphologies and sizes.

  15. Convenient, rapid synthesis of silver nanocubes and nanowires via a microwave-assisted polyol method

    International Nuclear Information System (INIS)

    Chen Dapeng; Qiao Xueliang; Chen Jianguo; Jiang Renzhi; Qiu Xiaolin

    2010-01-01

    Silver nanostructures have been synthesized via a microwave-assisted polyol method by adding sodium sulfide (Na 2 S) into the solution. An interesting morphology evolution can be observed by adjusting the concentration of Na 2 S and the heating power. It is found that the ideal concentration of Na 2 S is 31.25-500 μM for the fast reduction of Ag + at 300 W under optimal conditions for producing monodispersed silver nanocubes. When the heating power is increased to 400 W, 62.5-250 μM is the ideal concentration of Na 2 S for the synthesis of silver nanocubes. On increasing the concentration of Na 2 S (>500 μM), a mixture of silver nanowires, nanocubes, bipyramids, and irregular/quasispherical particles is synthesized at 300 and 400 W. In particular, an increase in the concentration of Na 2 S to 750 μM at 400 W leads to the production of a quantity of silver nanowires. In addition, silver nanocubes with controllable sizes can be obtained by changing the concentration of Na 2 S and the heating power. Compared to traditional wet-chemical methods, this method has the advantage of a marked decrease in reaction time to 3.5 min. Finally, our work provides a simple strategy for fabricating silver nanostructures with controllable morphologies and sizes.

  16. Low temperature synthesis & characterization of lead-free BCZT ceramics using molten salt method

    Science.gov (United States)

    Jai Shree, K.; Chandrakala, E.; Das, Dibakar

    2018-04-01

    Piezoelectric properties are greatly influenced by the synthesis route, microstructure, stoichiometry of the chemical composition, purity of the starting materials. In this study, molten salt method was used to prepare lead-free BCZT ceramics. Molten salt method is one of the simplestmethods to prepare chemically-purified, single phase powders in high yield often at lower temperatures and shorten reaction time. Calcination of the molten salt synthesized powders resulted in asingle-phase perovskite structure at 1000 °C which is ˜ 350 °C less than the conventional solid-sate reaction method. With increasing calcination temperature the average template size was increased (˜ 0.5-2 µm). Formation of well dispersive templates improves the sinterability at lower temperatures. Lead-free BCZT ceramics sintered at 1500 °C for 2 h resulted in homogenous and highly dense microstructure with ˜92% of the theoretical density and a grain size of ˜ 35 µm. This highly dense microstructure could enhance the piezoelectric properties of the system.

  17. Convenient, rapid synthesis of silver nanocubes and nanowires via a microwave-assisted polyol method.

    Science.gov (United States)

    Chen, Dapeng; Qiao, Xueliang; Qiu, Xiaolin; Chen, Jianguo; Jiang, Renzhi

    2010-01-15

    Silver nanostructures have been synthesized via a microwave-assisted polyol method by adding sodium sulfide (Na(2)S) into the solution. An interesting morphology evolution can be observed by adjusting the concentration of Na(2)S and the heating power. It is found that the ideal concentration of Na(2)S is 31.25-500 microM for the fast reduction of Ag(+) at 300 W under optimal conditions for producing monodispersed silver nanocubes. When the heating power is increased to 400 W, 62.5-250 microM is the ideal concentration of Na(2)S for the synthesis of silver nanocubes. On increasing the concentration of Na(2)S (>500 microM), a mixture of silver nanowires, nanocubes, bipyramids, and irregular/quasispherical particles is synthesized at 300 and 400 W. In particular, an increase in the concentration of Na(2)S to 750 microM at 400 W leads to the production of a quantity of silver nanowires. In addition, silver nanocubes with controllable sizes can be obtained by changing the concentration of Na(2)S and the heating power. Compared to traditional wet-chemical methods, this method has the advantage of a marked decrease in reaction time to 3.5 min. Finally, our work provides a simple strategy for fabricating silver nanostructures with controllable morphologies and sizes.

  18. Effect of synthesis methods and a comparative study of structural and magnetic properties of zinc ferrite

    Directory of Open Access Journals (Sweden)

    Md. Sazzad Hossain

    2017-10-01

    Full Text Available Zinc ferrite samples were prepared by two different routes which are chemical co-precipitation and standard solid state double sintering method. Structural properties of ZnFe2O4 were determined, and initial particle size was found as 5 nm in the samples prepared by chemical co-precipitation technique. The XRD patterns showed the single phase of ZnFe2O4 spinel structure and confirmed by the lattice parameter and the unmixed hkl values for both the synthesis techniques. M-H curves at room temperature showed superparamagnetic nature of the samples sintered from 200°C to 600°C, synthesized by chemical co-precipitation technique. The Mössbauer analysis at room temperature showed a doublet which is the signature of superparamagnetic nature, and it is in agreement with the acquired M-H curves. The magnetization of ZnFe2O4 synthesized by chemical co-precipitation method was found higher than the magnetization of ZnFe2O4 synthesized by the solid-state double sintering method in the sintering temperature from 1100°C to 1300°C.

  19. Bulk Synthesis and Characterization of Ti3Al Nanoparticles by Flow-Levitation Method

    Directory of Open Access Journals (Sweden)

    Shanjun Chen

    2013-01-01

    Full Text Available A novel bulk synthesis method for preparing high pure Ti3Al nanoparticles was developed by flow-levitation method (FL. The Ti and Al vapours ascending from the high temperature levitated droplet were condensed by cryogenic Ar gas under atmospheric pressure. The morphology, crystalline structure, and chemical composition of Ti3Al nanoparticles were, respectively, investigated by transmission electron microscopy, X-ray diffraction, and inductively coupled plasma atomic emission spectrometry. The results indicated that the Ti3Al powders are nearly spherical-shaped, and the particle size ranges from several nanometers to 100 nm in diameter. Measurements of the d-spacing from X-ray (XRD and electron diffraction studies confirmed that the Ti3Al nanoparticles have a hexagonal structure. A thin oxidation coating of 2-3 nm in thickness was formed around the particles after exposure to air. Based on the XPS measurements, the surface coating of the Ti3Al nanoparticles is a mixture of Al2O3 and TiO2. The production rate of Ti3Al nanoparticles was estimated to be about 3 g/h. This method has a great potential in mass production of Ti3Al nanoparticles.

  20. A review of the magnetic properties, synthesis methods and applications of maghemite

    Energy Technology Data Exchange (ETDEWEB)

    Shokrollahi, H., E-mail: shokrollahi@sutech.ac.ir

    2017-03-15

    It must be pointed out that maghemite (γ-Fe{sub 2}O{sub 3}) with a cubic spinel structure is a crucial material for various applications, including spin electronic devices, high-density magnetic recording, nano-medicines and biosensors. This paper has to do with a review study on the synthesis methods, magnetic properties and application of maghemite in the form of one-dimensional (1D) nanostructured materials, such as nanoparticles, nanotubes, nano-rods, and nanowires, as well as two-dimensional (2D) thin films. The results revealed that maghemite is widely used in the biomedical applications (hyperthermia, magnetic resonance imaging and drug delivery) and magnetic recording devices. The unmodified and Co/Mn modified maghemite thin films prepared by the dc-reactive magnetron sputtering show the excellent values of coercivity 2100 Oe and 3900 Oe, respectively, for the magnetic storage application. The super-paramagnetic particles with 7 nm size and the saturation magnetization of 80 emu/g prepared by the established thermolysis method are good candidates for bio-medical applications. - Highlights: • Among iron oxides, maghemite is one of the most important magnetic ceramics. • Maghemite is widely sued in magnetic recording and biomedicine. • This paper attempts to give an overview on the some important areas. • They contain synthetic methods, magnetic study, structural study and applications.

  1. Reported credibility techniques in higher education evaluation studies that use qualitative methods: A research synthesis.

    Science.gov (United States)

    Liao, Hongjing; Hitchcock, John

    2018-03-09

    This synthesis study examined the reported use of credibility techniques in higher education evaluation articles that use qualitative methods. The sample included 118 articles published in six leading higher education evaluation journals from 2003 to 2012. Mixed methods approaches were used to identify key credibility techniques reported across the articles, document the frequency of these techniques, and describe their use and properties. Two broad sets of techniques were of interest: primary design techniques (i.e., basic), such as sampling/participant recruitment strategies, data collection methods, analytic details, and additional qualitative credibility techniques (e.g., member checking, negative case analyses, peer debriefing). The majority of evaluation articles reported use of primary techniques although there was wide variation in the amount of supporting detail; most of the articles did not describe the use of additional credibility techniques. This suggests that editors of evaluation journals should encourage the reporting of qualitative design details and authors should develop strategies yielding fuller methodological description. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. SYNTHESIS OF INFORMATION MODEL FOR ALTERNATIVE FUNCTIONAL DIAGNOSTICS PROCEDURE

    OpenAIRE

    P. F. Shchapov; R. P. Miguschenko

    2014-01-01

    Probabilistic approaches in information theory and information theory of measurement, allowing to calculate and analyze the amount expected to models measuring conversions and encoding tasks random measurement signals were considered. A probabilistic model of diagnostic information model transformation and diagnostic procedures was developed. Conditions for obtaining the maximum amount of diagnostic information were found out.

  3. Modeling error distributions of growth curve models through Bayesian methods.

    Science.gov (United States)

    Zhang, Zhiyong

    2016-06-01

    Growth curve models are widely used in social and behavioral sciences. However, typical growth curve models often assume that the errors are normally distributed although non-normal data may be even more common than normal data. In order to avoid possible statistical inference problems in blindly assuming normality, a general Bayesian framework is proposed to flexibly model normal and non-normal data through the explicit specification of the error distributions. A simulation study shows when the distribution of the error is correctly specified, one can avoid the loss in the efficiency of standard error estimates. A real example on the analysis of mathematical ability growth data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 is used to show the application of the proposed methods. Instructions and code on how to conduct growth curve analysis with both normal and non-normal error distributions using the the MCMC procedure of SAS are provided.

  4. Development of modelling method selection tool for health services management: from problem structuring methods to modelling and simulation methods.

    Science.gov (United States)

    Jun, Gyuchan T; Morris, Zoe; Eldabi, Tillal; Harper, Paul; Naseer, Aisha; Patel, Brijesh; Clarkson, John P

    2011-05-19

    There is an increasing recognition that modelling and simulation can assist in the process of designing health care policies, strategies and operations. However, the current use is limited and answers to questions such as what methods to use and when remain somewhat underdeveloped. The aim of this study is to provide a mechanism for decision makers in health services planning and management to compare a broad range of modelling and simulation methods so that they can better select and use them or better commission relevant modelling and simulation work. This paper proposes a modelling and simulation method comparison and selection tool developed from a comprehensive literature review, the research team's extensive expertise and inputs from potential users. Twenty-eight different methods were identified, characterised by their relevance to different application areas, project life cycle stages, types of output and levels of insight, and four input resources required (time, money, knowledge and data). The characterisation is presented in matrix forms to allow quick comparison and selection. This paper also highlights significant knowledge gaps in the existing literature when assessing the applicability of particular approaches to health services management, where modelling and simulation skills are scarce let alone money and time. A modelling and simulation method comparison and selection tool is developed to assist with the selection of methods appropriate to supporting specific decision making processes. In particular it addresses the issue of which method is most appropriate to which specific health services management problem, what the user might expect to be obtained from the method, and what is required to use the method. In summary, we believe the tool adds value to the scarce existing literature on methods comparison and selection.

  5. Effect of Synthesis Method of La1 - x Sr x MnO3 Manganite Nanoparticles on Their Properties

    Science.gov (United States)

    Shlapa, Yulia; Solopan, Sergii; Belous, Anatolii; Tovstolytkin, Alexandr

    2018-01-01

    Nanoparticles of lanthanum-strontium manganite were synthesized via different methods, namely, sol-gel method, precipitation from non-aqueous solution, and precipitation from reversal microemulsions. It was shown that the use of organic compounds and non-aqueous media allowed significantly decreasing of the crystallization temperature of nanoparticles, and the single-phased crystalline product was formed in one stage. Morphology and properties of nanoparticles depended on the method and conditions of the synthesis. The heating efficiency directly depended on the change in the magnetic parameters of nanoparticles, especially on the magnetization. Performed studies showed that each of these methods of synthesis can be used to obtain weakly agglomerated manganite nanoparticles; however, particles synthesized via sol-gel method are more promising for use as hyperthermia inducers. PACS: 61.46.Df 75.75.Cd 81.20. Fw

  6. Functional methods in the generalized Dicke model

    International Nuclear Information System (INIS)

    Alcalde, M. Aparicio; Lemos, A.L.L. de; Svaiter, N.F.

    2007-01-01

    The Dicke model describes an ensemble of N identical two-level atoms (qubits) coupled to a single quantized mode of a bosonic field. The fermion Dicke model should be obtained by changing the atomic pseudo-spin operators by a linear combination of Fermi operators. The generalized fermion Dicke model is defined introducing different coupling constants between the single mode of the bosonic field and the reservoir, g 1 and g 2 for rotating and counter-rotating terms respectively. In the limit N -> ∞, the thermodynamic of the fermion Dicke model can be analyzed using the path integral approach with functional method. The system exhibits a second order phase transition from normal to superradiance at some critical temperature with the presence of a condensate. We evaluate the critical transition temperature and present the spectrum of the collective bosonic excitations for the general case (g 1 ≠ 0 and g 2 ≠ 0). There is quantum critical behavior when the coupling constants g 1 and g 2 satisfy g 1 + g 2 =(ω 0 Ω) 1/2 , where ω 0 is the frequency of the mode of the field and Ω is the energy gap between energy eigenstates of the qubits. Two particular situations are analyzed. First, we present the spectrum of the collective bosonic excitations, in the case g 1 ≠ 0 and g 2 ≠ 0, recovering the well known results. Second, the case g 1 ≠ 0 and g 2 ≠ 0 is studied. In this last case, it is possible to have a super radiant phase when only virtual processes are introduced in the interaction Hamiltonian. Here also appears a quantum phase transition at the critical coupling g 2 (ω 0 Ω) 1/2 , and for larger values for the critical coupling, the system enter in this super radiant phase with a Goldstone mode. (author)

  7. High-gravity combustion synthesis and in situ melt infiltration: A new method for preparing cemented carbides

    International Nuclear Information System (INIS)

    Liu, Guanghua; Li, Jiangtao; Yang, Zengchao; Guo, Shibin; Chen, Yixiang

    2013-01-01

    A new method of high-gravity combustion synthesis and in situ melt infiltration is reported for preparing cemented carbides, where hot nickel melt is in situ synthesized from a highly exothermic combustion reaction and then infiltrated into tungsten carbide powder compacts. The as-prepared sample showed a homogeneous microstructure, and its relative density, hardness and flexural strength were 94.4%, 84 HRA and 1.49 GPa, respectively. Compared with conventional powder metallurgy approaches, high-gravity combustion synthesis offers a fast and furnace-free way to produce cemented carbides

  8. A model of synthesis based on functional reasoning

    DEFF Research Database (Denmark)

    Hansen, Claus Thorp; Zavbi, R.

    2002-01-01

    In this paper we propose a model of how to carry out functional reasoning. The model is based on the domain theory, and it links the stepwise determination of the artefact´s characteristics during the design process to different ways of carrying out functional reasoning found in the literature....... The model proposes of a set of the mental objects and a number of ways to carry out functional reasoning available to the engineering designer. The result of the research presented in this paper is the building of a hypothesis "in the form of a model" with explanatory power....

  9. Radionuclide Transport Modelling: Current Status and Future Needs. Synthesis, Work Group Reports and Extended Abstracts

    International Nuclear Information System (INIS)

    2002-06-01

    The workshop identified a set of critical issues for the Swedish Nuclear Power Inspectorate (SKI) and the Swedish Radiation Protection Authority (SSI) to address in preparing for future reviews of license applications, which have subsequently been considered in preparing this synthesis. Structure for organising expert participation: A structure for organising expert participation in future reviews is proposed based on clearinghouses for (1) regulatory application and context, (2) engineered barrier systems, (3) geosphere, (4) biosphere, and (5) performance assessment integration and calculations. As part of their work, these clearinghouses could identify key issues that need to be resolved prior to future reviews. Performance assessment strategy and review context: Future reviews will be conducted in the context of regulations based on risk criteria; this leads to a need to review the methods used in probabilistic risk assessment, as well as the underlying process models. A plan is needed for accomplishing both aims. Despite the probabilistic framework, a need is anticipated for targeted, deterministic calculations to check particular assumptions. Priorities and ambition level for reviews: SKI's and SSI's resources can be more efficiently utilised by an early review of SKB's safety case, so that if necessary the authorities can make an early start on evaluating topics that are of primary significance to the safety case. As a guide to planning for allocation of effort in future reviews, this workshop produced a preliminary ranking of technical issues, on a scale from 'non-controversial' to 'requiring independent modelling,' Analysis of repository system and scenarios: Systems analysis tools including features/events/processes encyclopaedias, process-influence diagrams, and assessment-model flowcharts should be used as review tools, to check the processes and influences considered in SKB's analyses, and to evaluate the comprehensiveness of the scenarios that are

  10. New 1,2,4-triazine bearing compounds: molecular modeling, synthesis and biotesting

    Directory of Open Access Journals (Sweden)

    Negrutska V. V.

    2009-12-01

    Full Text Available Aim. To enlarge a spectrum of biologically active compounds in the series of the 1,2,4-triazino[5,6-b] [1,4]benzothiazine (1,2,4-TBT derivatives and reveal among them efficient inhibitors of RNA synthesis Methods. The methods of structure optimization of the 3-oxo-1,2,4-TBT by fragment-oriented substitution, the molecular doking of new structures in a virtual target, the rational chemical synthesis of the theoretically predicted compounds and their testing in the system of transcription in vitro. Results. The series of 1,2,4-TBT derivatives with substituents in the benzene and triazine cycles of a base molecule were synthesized. The testing of synthesized compounds in the in vitro transcription system directed by T7 RNA polymerase revealed the structure- and concentration-dependent inhibition of the RNA synthesis by some of these compounds. The experimental and virtual screening data for all investigated compounds have a good correlation. It was found that most effective derivative is the 3-oxo-8-butyl-1,2,4-TBT which completely inhibited transcription at the concentration of 6 mg/ml. Conclusions. The biotesting results allow us to assume that the inhibition of RNA synthesis is caused by binding of the 3-oxo- 8-butyl-1,2,4-TBT to both free RNA polymerase molecules and those including in a transcriptional complex with DNA

  11. Determining the Parameters of Importance of a Graphene Synthesis Process Using Design-of-Experiments Method

    Directory of Open Access Journals (Sweden)

    Udit Narula

    2016-07-01

    Full Text Available A systematic method to identify key factors that control the synthesis of Physical Vapor Deposition (PVD-based graphene on copper is necessary for engineering graphene growth. The statistical design-of-experiments method is employed and demonstrated in this work in order to fulfill the necessity. Full-factorial design-of-experiments are performed to examine the significance of the main effects and the extent of the interactions of the controlling factors, which are responsible for the number of layers and the quality of the grown graphene. We found that a thinner amorphous carbon layer and a higher annealing temperature are suitable for the growth of mono-layer/few-layer graphene with low defects, while the effect of annealing time has a trade-off and needs to be optimized further. On the other hand, the same treatment, but with larger annealing times will result in multi-layer graphene and low defects. The results obtained from the analysis of the design-of-experiments are verified experimentally with Raman characterization.

  12. Evaluation of Various Synthesis Methods for Calcite-Precipitated Calcium Carbonate (PCC) Formation

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishna, Chilakala [Hanil Cement Corporation, Danyang (Korea, Republic of); Thenepalli, Thriveni; Ahn, Ji Whan [Korea Institute of Geoscience and Mineral Resources, Daejeon (Korea, Republic of)

    2017-06-15

    This review paper evaluates different kinds of synthesis methods for calcite precipitated calcium carbonates by using different materials. The various processing routes of calcite with different compositions are reported and the possible optimum conditions required to synthesize a desired particle sizes of calcite are predicted. This paper mainly focuses on that the calcite morphology and size of the particles by carbonation process using loop reactors. In this regard, we have investigated various parameters such as CO{sub 2} flow rate, Ca (OH){sub 2} concentration, temperature, pH effect, reaction time and loop reactor mechanism with orifice diameter. The research results illustrate the formation of well-defined and pure calcite crystals with controlled crystal growth and particle size, without additives or organic solvents. The crystal growth and particle size can be controlled, and smaller sizes are obtained by decreasing the Ca (OH){sub 2} concentration and increasing the CO{sub 2} flow rate at lower temperatures with suitable pH. The crystal structure of obtained calcite was characterized by using X-ray diffraction method and the morphology by scanning electron microscope (SEM). The result of x-ray diffraction recognized that the calcite phase of calcium carbonate was the dominating crystalline structure.

  13. Synthesis and characterization of black amorphous titanium oxide nanoparticles by spark discharge method

    Science.gov (United States)

    Sabzehparvar, Milad; Kiani, Fatemeh; Tabrizi, Nooshin Salman

    2018-01-01

    In the last decade, while crystalline titanium oxide nanoparticles have been extensively studied, the studies on amorphous polymorph nanoparticles are relatively rare and limited to the ab initio studies. We have synthesized black amorphous titanium oxide nanoparticles using, for the first time, spark ablation in the argon gas followed by oxidation at atmospheric conditions. The produced nanoparticles were characterized by various characterization methods to study their structure, size, morphology, surface area and optical properties. XRD analysis indicated the formation of an amorphous TiO2 phase together with Ti, TiO and Ti2O3 crystalline phases. FESEM demonstrated that the produced nanoparticles had a narrow size distribution. EDS analysis suggested the formation of nonstoichiometric titanium oxide. TEM and SAED analyses showed that the majority of nanoparticles were in amorphous state and possessed an average size of about 5.2 nm. A very high specific surface area of 310 m2/g was measured for the produced nanoparticles by the BJH analysis. These titanium oxide nanoparticles showed an optical band gap of around 3.2eV and an enhanced absorption in the whole visible spectrum measured by the UV-Vis and DRS analyses due to the oxygen deficiency. These results indicate that the spark ablation in the gas phase is a facile method for the synthesis of black amorphous titanium oxide nanoparticles.

  14. A review of the magnetic properties, synthesis methods and applications of maghemite

    Science.gov (United States)

    Shokrollahi, H.

    2017-03-01

    It must be pointed out that maghemite (γ-Fe2O3) with a cubic spinel structure is a crucial material for various applications, including spin electronic devices, high-density magnetic recording, nano-medicines and biosensors. This paper has to do with a review study on the synthesis methods, magnetic properties and application of maghemite in the form of one-dimensional (1D) nanostructured materials, such as nanoparticles, nanotubes, nano-rods, and nanowires, as well as two-dimensional (2D) thin films. The results revealed that maghemite is widely used in the biomedical applications (hyperthermia, magnetic resonance imaging and drug delivery) and magnetic recording devices. The unmodified and Co/Mn modified maghemite thin films prepared by the dc-reactive magnetron sputtering show the excellent values of coercivity 2100 Oe and 3900 Oe, respectively, for the magnetic storage application. The super-paramagnetic particles with 7 nm size and the saturation magnetization of 80 emu/g prepared by the established thermolysis method are good candidates for bio-medical applications.

  15. Synthesis and characterization of lanthanum monoaluminate by co-precipitation method

    Directory of Open Access Journals (Sweden)

    Madoui N.

    2012-06-01

    Full Text Available Our contribution has focused on the synthesis and characterization of lanthanum monoaluminate LaAlO3 by the method of co-precipitation. The powder was successfully synthesized using NaOH, La (NO33.6H2O and Al (NO33.9H2O as raw materials by this method and calcined at different temperatures. It was characterized by several techniques: Fourier transform infrared spectroscopy (FT-IR, thermogravimetric and differential thermal analysis (TGA/DTA, X-ray diffraction (XRD and laser diffusion. All the results for physico-chemicals characterizations show that the crystallization temperature of the LaAlO3 precursor gels precipitated is estimated as 790 °C by TG/DTA. The XRD pattern of the LaAlO3 precursor gels calcined at 700 °C for 6 h has a perovskite structure of rhombohedral hexagonal phase formed and the presence of crystalline impurities is not found. The crystallite size of LaAlO3 slightly increases from 31to 44.5 nm with calcination temperature increasing from 700to1000 °C for 6 h.

  16. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    Energy Technology Data Exchange (ETDEWEB)

    Shimpi, Navinchandra G., E-mail: navin_shimpi@rediffmail.com [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Jain, Shilpa [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Karmakar, Narayan [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Shah, Akshara [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Kothari, D.C. [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); National Centre for Nanosciences & Nanotechnology, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Mishra, Satyendra [University Institute of Chemical Technology, North Maharashtra University, Jalgaon (India)

    2016-12-30

    Highlights: • Synthesis using a simple and cost-effective wet chemical process. • Uniform, monodispersed and pure nanoparticles. • Pencil shaped rods with sharp tips. • Understanding of Growth mechanism. • Efficient LPG sensing with high response. • Morphology dependent sensing. - Abstract: ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  17. Synthesis and Self-Assembly of Gold Nanoparticles by Chemically Modified Polyol Methods under Experimental Control

    Directory of Open Access Journals (Sweden)

    Nguyen Viet Long

    2013-01-01

    Full Text Available In our present research, bottom-up self-assembly of gold (Au nanoparticles on a flat copper (Cu substrate is performed by a facile method. The very interesting evidence of self-assembly of Au nanoparticles on the top of the thin assembled layer was observed by scanning electron microscopy (SEM. We had discovered one of the most general and simple methods for the self-assembly of metal nanoparticles. The general physical and chemical mechanisms of the evaporation process of the solvents can be used for self-assembly of the as-prepared nanoparticles. The important roles of molecules of the used solvents are very critical to self-assembly of the as-prepared Au nanoparticles in the case without using any polymers for those processes. It is clear that self-assembly of such one nanosystem of the uniform Au nanoparticles is fully examined. Finally, an exciting surface plasmon resonance (SPR phenomenon of the pure Au nanoparticles in the solvent was fully discovered in their exciting changes of the narrow and large SPR bands according to synthesis time. The SPR was considered as the collective oscillation of valence electrons of the surfaces of the pure Au nanoparticles in the solvent by incident ultraviolet-visible light. Then, the frequency of light photons matches the frequency of the oscillation of surface electrons of the Au nanoparticles that are excited.

  18. Evaluation of Various Synthesis Methods for Calcite-Precipitated Calcium Carbonate (PCC) Formation

    International Nuclear Information System (INIS)

    Ramakrishna, Chilakala; Thenepalli, Thriveni; Ahn, Ji Whan

    2017-01-01

    This review paper evaluates different kinds of synthesis methods for calcite precipitated calcium carbonates by using different materials. The various processing routes of calcite with different compositions are reported and the possible optimum conditions required to synthesize a desired particle sizes of calcite are predicted. This paper mainly focuses on that the calcite morphology and size of the particles by carbonation process using loop reactors. In this regard, we have investigated various parameters such as CO 2 flow rate, Ca (OH) 2 concentration, temperature, pH effect, reaction time and loop reactor mechanism with orifice diameter. The research results illustrate the formation of well-defined and pure calcite crystals with controlled crystal growth and particle size, without additives or organic solvents. The crystal growth and particle size can be controlled, and smaller sizes are obtained by decreasing the Ca (OH) 2 concentration and increasing the CO 2 flow rate at lower temperatures with suitable pH. The crystal structure of obtained calcite was characterized by using X-ray diffraction method and the morphology by scanning electron microscope (SEM). The result of x-ray diffraction recognized that the calcite phase of calcium carbonate was the dominating crystalline structure.

  19. Synthesis of Li2MO3 (M = Ti or Zr) by the combustion method

    International Nuclear Information System (INIS)

    Cruza, D.; Bulbuliana, S.; Cruza, D.; Pfeifferc, H.

    2006-01-01

    The advantages and disadvantages of the combustion method to prepare Li 2 TiO 3 and Li 2 ZrO 3 ceramics were studied. Firstly, the ceramic powders were prepared by the combustion process using LiOH, MO 2 (where M=Ti or Zr) and urea in different molar ratios (from 2:1:3 to 3:1:3) at different temperatures for 5 minutes. Li 2 TiO 3 and Li 2 ZrO 3 were also obtained by the solid-state method, and the results were compared with those obtained by the combustion process. The powders were characterized by X-ray diffraction and scanning electron microscopy. It was found that the combustion process reduces the synthesis time of Li 2 TiO 3 (1 minute at 750 C), but it does not have any advantage on producing Li 2 ZrO 3 , due to thermodynamic factors. On the other hand, the combustion process produces carbon contaminants in the solids. It was necessary to add excess of lithium hydroxide, in order to compensate the quantity of Li sublimated during the production of the ceramics. Finally, it seems that both reactions follow the same mechanism, which is determined by the lithium diffusion into the metal oxides. (authors)

  20. Novel method of room temperature ionic liquid assisted Fe3O4 nanocubes and nanoflakes synthesis

    International Nuclear Information System (INIS)

    Ramalakshmi, M.; Shakkthivel, P.; Sundrarajan, M.; Chen, S.M.

    2013-01-01

    Graphical abstract: - Highlights: • First time [Bmim][TfO] IL is used for the Fe 3 O 4 nanoparticle synthesis. • Novel method tunes Fe 3 O 4 nanocubes and nanoflakes forms influenced by the base and IL. • Fe 3 O 4 oxidized topotactically into γ-Fe 2 O 3 nanoparticles by annealing and base. • Uniform morphology with average size of 33 nm negligible superstructure are formed. • Ms values are characterized by thin layer of γ-Fe 2 O 3 on the nanoparticle surface. - Abstract: For the first time, the nanomagnetite superparamagnetic particles are successfully synthesized by precipitation method using 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate [Bmim][TfO] ionic liquid medium/surfactant. The obtained Fe 3 O 4 particles are nanocubes and nanoflakes and this formation is influenced by the base concentration and anisotropic circumstances produced by the ionic liquid and their size varies from 20 nm to 150 × 300 nm (width × length). The synthesized magnetite nanoparticles are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM) and Vibrating sample magnetometer (VSM) studies. The results show that the core of the Fe 3 O 4 nanoparticles is surrounded by a thin layer of γ-Fe 2 O 3 by topotactical partial oxidation, which is remarkably proceed with the subsequent calcination. The magnetite nanocubes have high saturation magnetization value and exhibit superparamagnetic hysteresis loop

  1. Comparative Studies of Population Synthesis Models in the ...

    Indian Academy of Sciences (India)

    2014-01-08

    Jan 8, 2014 ... Strömgren photometry to measure reliable parameter-sensitive colours and estimate precise model ages and metallicities. The assessment of. Rakos/Schulz ... Overall, the assessment finds modified Strömgren photometry ... The history of stellar population modelling dates back to the attempts by Crampin.

  2. Mathematical models and methods for planet Earth

    CERN Document Server

    Locatelli, Ugo; Ruggeri, Tommaso; Strickland, Elisabetta

    2014-01-01

    In 2013 several scientific activities have been devoted to mathematical researches for the study of planet Earth. The current volume presents a selection of the highly topical issues presented at the workshop “Mathematical Models and Methods for Planet Earth”, held in Roma (Italy), in May 2013. The fields of interest span from impacts of dangerous asteroids to the safeguard from space debris, from climatic changes to monitoring geological events, from the study of tumor growth to sociological problems. In all these fields the mathematical studies play a relevant role as a tool for the analysis of specific topics and as an ingredient of multidisciplinary problems. To investigate these problems we will see many different mathematical tools at work: just to mention some, stochastic processes, PDE, normal forms, chaos theory.

  3. A sequential high-yielding large-scale solution-method for synthesis of philanthotoxin analogues

    DEFF Research Database (Denmark)

    Wellendorph, Petrine; Jaroszewski, Jerzy W; Hansen, Steen Honoré

    2003-01-01

    A general, improved procedure for rapid synthesis of philanthotoxin analogues, a pharmacologically important class of polyamine conjugates, is described. The solution-phase procedure is illustrated by gram-scale synthesis of philanthotoxins PhTX-343 and PhTX-12. Selectively protected polyamines...

  4. Gait variability: methods, modeling and meaning

    Directory of Open Access Journals (Sweden)

    Hausdorff Jeffrey M

    2005-07-01

    Full Text Available Abstract The study of gait variability, the stride-to-stride fluctuations in walking, offers a complementary way of quantifying locomotion and its changes with aging and disease as well as a means of monitoring the effects of therapeutic interventions and rehabilitation. Previous work has suggested that measures of gait variability may be more closely related to falls, a serious consequence of many gait disorders, than are measures based on the mean values of other walking parameters. The Current JNER series presents nine reports on the results of recent investigations into gait variability. One novel method for collecting unconstrained, ambulatory data is reviewed, and a primer on analysis methods is presented along with a heuristic approach to summarizing variability measures. In addition, the first studies of gait variability in animal models of neurodegenerative disease are described, as is a mathematical model of human walking that characterizes certain complex (multifractal features of the motor control's pattern generator. Another investigation demonstrates that, whereas both healthy older controls and patients with a higher-level gait disorder walk more slowly in reduced lighting, only the latter's stride variability increases. Studies of the effects of dual tasks suggest that the regulation of the stride-to-stride fluctuations in stride width and stride time may be influenced by attention loading and may require cognitive input. Finally, a report of gait variability in over 500 subjects, probably the largest study of this kind, suggests how step width variability may relate to fall risk. Together, these studies provide new insights into the factors that regulate the stride-to-stride fluctuations in walking and pave the way for expanded research into the control of gait and the practical application of measures of gait variability in the clinical setting.

  5. FDTD method and models in optical education

    Science.gov (United States)

    Lin, Xiaogang; Wan, Nan; Weng, Lingdong; Zhu, Hao; Du, Jihe

    2017-08-01

    In this paper, finite-difference time-domain (FDTD) method has been proposed as a pedagogical way in optical education. Meanwhile, FDTD solutions, a simulation software based on the FDTD algorithm, has been presented as a new tool which helps abecedarians to build optical models and to analyze optical problems. The core of FDTD algorithm is that the time-dependent Maxwell's equations are discretized to the space and time partial derivatives, and then, to simulate the response of the interaction between the electronic pulse and the ideal conductor or semiconductor. Because the solving of electromagnetic field is in time domain, the memory usage is reduced and the simulation consequence on broadband can be obtained easily. Thus, promoting FDTD algorithm in optical education is available and efficient. FDTD enables us to design, analyze and test modern passive and nonlinear photonic components (such as bio-particles, nanoparticle and so on) for wave propagation, scattering, reflection, diffraction, polarization and nonlinear phenomena. The different FDTD models can help teachers and students solve almost all of the optical problems in optical education. Additionally, the GUI of FDTD solutions is so friendly to abecedarians that learners can master it quickly.

  6. Methods of synthesis and performance improvement of lithium iron phosphate for high rate Li-ion batteries: A review

    Directory of Open Access Journals (Sweden)

    T.V.S.L. Satyavani

    2016-03-01

    Full Text Available Lithium ion battery technology has the potential to meet the requirements of high energy density and high power density applications. A continuous search for novel materials is pursued continually to exploit the latent potential of this technology. In this review paper, methods for preparation of Lithium Iron Phosphate are discussed which include solid state and solution based synthesis routes. The methods to improve the electrochemical performance of lithium iron phosphate are presented in detail.

  7. Modeling, Analysis, Simulation, and Synthesis of Biomolecular Networks

    National Research Council Canada - National Science Library

    Ruben, Harvey; Kumar, Vijay; Sokolsky, Oleg

    2006-01-01

    ...) a first example of reachability analysis applied to a biomolecular system (lactose induction), 4) a model of tetracycline resistance that discriminates between two possible mechanisms for tetracycline diffusion through the cell membrane, and 5...

  8. Bourbaki's structure theory in the problem of complex systems simulation models synthesis and model-oriented programming

    Science.gov (United States)

    Brodsky, Yu. I.

    2015-01-01

    The work is devoted to the application of Bourbaki's structure theory to substantiate the synthesis of simulation models of complex multicomponent systems, where every component may be a complex system itself. An application of the Bourbaki's structure theory offers a new approach to the design and computer implementation of simulation models of complex multicomponent systems—model synthesis and model-oriented programming. It differs from the traditional object-oriented approach. The central concept of this new approach and at the same time, the basic building block for the construction of more complex structures is the concept of models-components. A model-component endowed with a more complicated structure than, for example, the object in the object-oriented analysis. This structure provides to the model-component an independent behavior-the ability of standard responds to standard requests of its internal and external environment. At the same time, the computer implementation of model-component's behavior is invariant under the integration of models-components into complexes. This fact allows one firstly to construct fractal models of any complexity, and secondly to implement a computational process of such constructions uniformly-by a single universal program. In addition, the proposed paradigm allows one to exclude imperative programming and to generate computer code with a high degree of parallelism.

  9. Thermo-hydro-mechanical modelling of buffer, synthesis report

    International Nuclear Information System (INIS)

    Toprak, E.; Mokni, N.; Olivella, S.; Pintado, X.

    2013-08-01

    This study addresses analyses of coupled thermo-hydro-mechanical (THM) processes in a scheme considered for the spent nuclear fuel repository in Olkiluoto (Finland). The finite element code CODE B RIGHT is used to perform modelling calculations. The objective of the THM modelling was to study some fundamental design parameters. The time required to reach full saturation, the maximum temperature reached in the canister, the deformations in the buffer-backfill interface, the stress-deformation balance between the buffer and the backfill, the swelling pressure developed and the homogenization process development are critical variables. Because of the complexity of the THM processes developed, only a single deposition hole has been modelled with realistic boundary conditions which take into account the entire repository. A thermal calculation has been performed to adopt appropriate boundary conditions for a reduced domain. The modelling has been done under axisymmetric conditions. As a material model for the buffer bentonite and backfill soil, the Barcelona Basic Model (BBM) has been used. Simulation of laboratory tests conducted at B and Tech under supervision of Posiva has been carried out in order to determine the fundamental mechanical parameters for modelling the behaviour of MX-80 bentonite using the BBM model. The modelling process of the buffer-backfill interface is an essential part of tunnel backfill design. The calculations will aim to determine deformations in this intersection, the behaviour of which is important for the buffer swelling. The homogenization process is a key issue as well. Porosity evolution during the saturation process is evaluated in order to check if the final saturated density accomplishes the homogenization requirements. This report also describes the effect of the existence of an air-filled gap located between the canister and the bentonite block rings in thermo-hydro-mechanical behaviour of the future spent nuclear fuel repository in

  10. New labeling methods via organometallic species: new synthesis of a chiral methyl group

    International Nuclear Information System (INIS)

    Faucher, Nicolas

    2000-01-01

    Chapter 1: New labeling methods via organometallic species. In the first part of this work, we have developed a new labeling strategy based on the hydrogenolysis of organolithium compounds with tritium gas or deuterium gas. This reaction is catalyzed with palladium on charcoal and leads to the labelled compounds with direct replacement of the proton by its isotopes ( 2 H or 3 H) without further chemical modification of the target molecule. Using this strategy, tritium or deuterium atoms can be introduced in a region but also in a stereoselective fashion with more than 90% ee. The former result was obtained using (-)-sparteine during the lithiation step. Chapter II: New synthesis of a chiral methyl group. In the second part of this work, we have developed a new synthetic method to prepare chiral ditosyl-methylamine using 4,5-disubstituted oxazolidines. Dia-stereoselective substitution of the methoxy group of a 2-alkoxy-oxazolidine by a deuteride in the presence of a Lewis acid leads to the 2-deutero-oxazolidine in a highly stereoselective fashion (de = 100%). Still using a lewis acid, a tritiated hydride open the former 2-deutero-oxazolidine to afford chiral methyl group borne by the nitrogen. Further de-protection and re-protection steps lead to the ditosyl-methylamine with an ee of 65% (RIS= 83/17). Nowadays, this is the best known synthetic method, not only in terms of enantioselectivity but also in terms of chemical yield and number of radioactive steps. As NTs 2 is a fairly good leaving group, the ditosyl-methylamine offers the possibility of introducing chiral methyl group in many substrates using a S N 2 reaction with various nucleophiles. This last point leads to many potential applications in the field of biochemistry or for mechanical studies. (author) [fr

  11. Mechanistic insights on one-phase vs. two-phase Brust–Schiffrin method synthesis of Au nanoparticles with dioctyl-diselenides

    Energy Technology Data Exchange (ETDEWEB)

    Zaluzhna, Oksana; Li, Ying; Zangmeister, Chris; Allison, Thomas C.; Tong, YuYe J.

    2012-01-01

    Metal precursors in the one-phase (1p) and two-phase (2p) Brust-Schiffrin method (BSM) synthesis of Au nanoparticles (NPs) using dioctyl-diselenides were identified. A single dominant type of metal precursor was found in the 1p synthesis as compared to multiple ones in the 2p synthesis, which was proposed as the key reason why the former is better than the latter.

  12. Mechanistic insights on one-phase vs. two-phase Brust-Schiffrin method synthesis of Au nanoparticles with dioctyl-diselenides.

    Science.gov (United States)

    Zaluzhna, Oksana; Li, Ying; Zangmeister, Chris; Allison, Thomas C; Tong, YuYe J

    2012-01-11

    Metal precursors in the one-phase (1p) and two-phase (2p) Brust-Schiffrin method (BSM) synthesis of Au nanoparticles (NPs) using dioctyl-diselenides were identified. A single dominant type of metal precursor was found in the 1p synthesis as compared to multiple ones in the 2p synthesis, which was proposed as the key reason why the former is better than the latter. This journal is © The Royal Society of Chemistry 2012

  13. Free wake models for vortex methods

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, K. [Technical Univ. Berlin, Aerospace Inst. (Germany)

    1997-08-01

    The blade element method works fast and good. For some problems (rotor shapes or flow conditions) it could be better to use vortex methods. Different methods for calculating a wake geometry will be presented. (au)

  14. MATHEMATICAL AND COMPUTATIONAL MODELLING OF RIBOSOMAL MOVEMENT AND PROTEIN SYNTHESIS: AN OVERVIEW

    Directory of Open Access Journals (Sweden)

    Tobias von der Haar

    2012-04-01

    Full Text Available Translation or protein synthesis consists of a complex system of chemical reactions, which ultimately result in decoding of the mRNA and the production of a protein. The complexity of this reaction system makes it difficult to quantitatively connect its input parameters (such as translation factor or ribosome concentrations, codon composition of the mRNA, or energy availability to output parameters (such as protein synthesis rates or ribosome densities on mRNAs. Mathematical and computational models of translation have now been used for nearly five decades to investigate translation, and to shed light on the relationship between the different reactions in the system. This review gives an overview over the principal approaches used in the modelling efforts, and summarises some of the major findings that were made.

  15. Subtask 2.4 - Integration and Synthesis in Climate Change Predictive Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Jaroslav Solc

    2009-06-01

    The Energy & Environmental Research Center (EERC) completed a brief evaluation of the existing status of predictive modeling to assess options for integration of our previous paleohydrologic reconstructions and their synthesis with current global climate scenarios. Results of our research indicate that short-term data series available from modern instrumental records are not sufficient to reconstruct past hydrologic events or predict future ones. On the contrary, reconstruction of paleoclimate phenomena provided credible information on past climate cycles and confirmed their integration in the context of regional climate history is possible. Similarly to ice cores and other paleo proxies, acquired data represent an objective, credible tool for model calibration and validation of currently observed trends. It remains a subject of future research whether further refinement of our results and synthesis with regional and global climate observations could contribute to improvement and credibility of climate predictions on a regional and global scale.

  16. Eluding the Physical Constraints in a Nonlinear Interaction Sound Synthesis Model for Gesture Guidance

    Directory of Open Access Journals (Sweden)

    Etienne Thoret

    2016-06-01

    Full Text Available In this paper, a flexible control strategy for a synthesis model dedicated to nonlinear friction phenomena is proposed. This model enables to synthesize different types of sound sources, such as creaky doors, singing glasses, squeaking wet plates or bowed strings. Based on the perceptual stance that a sound is perceived as the result of an action on an object we propose a genuine source/filter synthesis approach that enables to elude physical constraints induced by the coupling between the interacting objects. This approach makes it possible to independently control and freely combine the action and the object. Different implementations and applications related to computer animation, gesture learning for rehabilitation and expert gestures are presented at the end of this paper.

  17. Sample-based engine noise synthesis using an enhanced pitch-synchronous overlap-and-add method.

    Science.gov (United States)

    Jagla, Jan; Maillard, Julien; Martin, Nadine

    2012-11-01

    An algorithm for the real time synthesis of internal combustion engine noise is presented. Through the analysis of a recorded engine noise signal of continuously varying engine speed, a dataset of sound samples is extracted allowing the real time synthesis of the noise induced by arbitrary evolutions of engine speed. The sound samples are extracted from a recording spanning the entire engine speed range. Each sample is delimitated such as to contain the sound emitted during one cycle of the engine plus the necessary overlap to ensure smooth transitions during the synthesis. The proposed approach, an extension of the PSOLA method introduced for speech processing, takes advantage of the specific periodicity of engine noise signals to locate the extraction instants of the sound samples. During the synthesis stage, the sound samples corresponding to the target engine speed evolution are concatenated with an overlap and add algorithm. It is shown that this method produces high quality audio restitution with a low computational load. It is therefore well suited for real time applications.

  18. Synthesis of cobalt alloy through smelting method and its characterization as prosthesis bone implant

    Energy Technology Data Exchange (ETDEWEB)

    Aminatun,, E-mail: ami-sofijan@yahoo.co.id; Putri, N.S Efinda, E-mail: ami-sofijan@yahoo.co.id; Indriani, Arista, E-mail: ami-sofijan@yahoo.co.id; Himawati, Umi, E-mail: ami-sofijan@yahoo.co.id; Hikmawati, Dyah, E-mail: ami-sofijan@yahoo.co.id; Suhariningsih, E-mail: ami-sofijan@yahoo.co.id [Department of physics, Faculty of Science and Technology, Airlangga University (Indonesia)

    2014-09-25

    Cobalt-based alloys are widely used as total hip and knee replacements because of their excellent properties, such as corrosion resistance, fatigue strength and biocompatibility. In this work, cobalt alloys with variation of Cr (28.5; 30; 31.5; 33, and 34.5% wt) have been synthesized by smelting method began with the process of compaction, followed by smelting process using Tri Arc Melting Furnace at 200A. Continued by homogenization process at recrystallization temperature (1250° C) for 3 hours to allow the atoms diffuses and transform into γ phase. The next process is rolling process which is accompanied by heating at 1200° C for ± 15 minutes and followed by quenching. This process is repeated until the obtained thickness of ± 1 mm. The evaluated material properties included microstructure, surface morphology, and hardness value. It was shown that microstructure of cobalt alloys with variation of Cr is dominant by γ phase, thus making the entire cobalt alloys have high hardness. It was also shown from the surface morphology of entire cobalt alloys sample indicated the whole process of synthesis that had good solubility were at flat surface area. Hardness value test showed all of cobalt alloys sample had high hardness, just variation of 33% Cr be in the range of ASTMF75, it were 345,24 VHN which is potential to be applied as an implant prosthesis.

  19. A high-throughput and quantitative method to assess the mutagenic potential of translesion DNA synthesis

    Science.gov (United States)

    Taggart, David J.; Camerlengo, Terry L.; Harrison, Jason K.; Sherrer, Shanen M.; Kshetry, Ajay K.; Taylor, John-Stephen; Huang, Kun; Suo, Zucai

    2013-01-01

    Cellular genomes are constantly damaged by endogenous and exogenous agents that covalently and structurally modify DNA to produce DNA lesions. Although most lesions are mended by various DNA repair pathways in vivo, a significant number of damage sites persist during genomic replication. Our understanding of the mutagenic outcomes derived from these unrepaired DNA lesions has been hindered by the low throughput of existing sequencing methods. Therefore, we have developed a cost-effective high-throughput short oligonucleotide sequencing assay that uses next-generation DNA sequencing technology for the assessment of the mutagenic profiles of translesion DNA synthesis catalyzed by any error-prone DNA polymerase. The vast amount of sequencing data produced were aligned and quantified by using our novel software. As an example, the high-throughput short oligonucleotide sequencing assay was used to analyze the types and frequencies of mutations upstream, downstream and at a site-specifically placed cis–syn thymidine–thymidine dimer generated individually by three lesion-bypass human Y-family DNA polymerases. PMID:23470999

  20. Investigation of the effective parameters on the synthesis of strontium hexaferrite nanoparticles by chemical coprecipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Davoodi, A., E-mail: akbardavudijamaloee@yahoo.com [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Zand Street, Shiraz (Iran, Islamic Republic of); Hashemi, B. [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Zand Street, Shiraz (Iran, Islamic Republic of)

    2012-01-25

    Strontium hexaferrite nanoparticles were synthesized by chemical coprecipitation method in the presence of polyvinylpyrrolidone (PVP) as a protective agent. A mixture of the deionized water/ethanol (50/50) was used as the solvent. The effects of PVP, pH of the solution, Fe{sup 3+}/Sr{sup 2+} molar ratio and calcination temperature of the precipitates on the synthesis of strontium hexaferrite samples were studied. X-ray diffraction (XRD), scanning electron microscope (SEM), thermal analysis (DTA-TGA), dynamic light scattering particle size analyzer (PSA) and vibrating sample magnetometer (VSM) were used to investigate the properties of the obtained samples. The results showed that increasing the pH from 9 to 13 or decreasing Fe{sup 3+}/Sr{sup 2+} molar ratio from 12 to 9 promoted SrFe{sub 12}O{sub 19} formation and decreased the size of nanoparticles. The minimum coercivity of 4733 Oe and maximum saturation magnetization of 51 emu/g were obtained by increasing the pH from 9 to 13. It was also concluded that PVP could be effective in decreasing the size of SrFe{sub 12}O{sub 19} nanoparticles and resulted to decrease the calcination temperature from 800 to 700 Degree-Sign C.

  1. Synthesis and characterization of eggshell-derived hydroxyapatite via mechanochemical method: A comparative study

    Science.gov (United States)

    Hamidi, A. A.; Salimi, M. N.; Yusoff, A. H. M.

    2017-04-01

    The focus of bone graft properties has developed through generations, from the ability to withstand mechanical stress to the ability to integrate with the biological structure. In recent years, the use of hydroxyapatite (HA) as bone graft material in orthopedic and dental applications has been increasing. HA is a natural occuring mineral with excellent bioactivity but relatively poor mechanical properties. It constitutes 96% portion of enamel in teeth and 67% portion of bone. HA can be extracted from animal bones or fabricated from synthetic or biologic sources. In this study, eggshells were used as raw material to synthesize eggshell-derived HA (EHA) via mechanochemical method. The synthesis of EHA involved CaO, which was obtained from the calcination of eggshells, and reaction with dicalcium hydrogen phosphate dihydrous (DCPD) or phosphoric acid (H3PO4). The effects of rotational speed and heat treatment temperature on EHA's characteristics were investigated. The characterization studies were carried out by using the Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) analysis and Scanning Electron Microscopy (SEM). HA powder was successfully synthesized with crystallite and particle sizes in the range of 8-47 nm and 250-550 nm respectively. It was observed from this study that the increase of milling rotational speed had increased the phase purity of EHA samples. Furthermore, the higher heating temperature of HA samples resulted in higher degree of crystallinity of HA and the appearance of β-tricalcium phosphate (β-TCP) as secondary phase.

  2. A new method for synthesis of As-Te chalcogenide films

    Science.gov (United States)

    Mochalov, Leonid; Nezhdanov, Aleksey; Usanov, Dmitry; Markelov, Aleksey; Trushin, Vladimir; Chidichimo, Giuseppe; De Filpo, Giovanni; Gogova, Daniela; Mashin, Aleksandr

    2017-11-01

    A novel Plasma Enhanced Chemical Vapor Deposition method for synthesis of amorphous AsxTe100-x (31 ≤ x ≤ 49) films is demonstrated. The innovative process has been developed in a non-equilibrium low-temperature argon plasma under reduced pressure, employing for the first time volatile As and Te as precursors. Utilization of inorganic precursors, in contrast to the typically used in CVD metal-organic precursors, has given us the chance to achieve ≿halcogenide As-Te films of very high quality and purity. Phase and structural evolution of the As-Te system, based on equilibrium coexistence of two phases (AsTe and As2Te3) has been studied. The dependence of structure and optical bandgap of the chalcogenide materials on their composition was established. The newly developed process is cost-effective and enables deposition of As-Te films with a thickness ranging from 10 nm to 10 μm, the latter is highly desireable for one-mode planar waveguides applications and in other components of integral optics.

  3. Synthesis and characterization of mesoporous MgO by template-free hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Hongmei, E-mail: hmcui@home.ipe.ac.cn [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, 1 Zhongguancun Road, Haidian District 100190, Beijing (China); Research Institute of Synthetic Crystals, 1 Hongsong Road, Chaoyang District 100018, Beijing (China); Wu, Xiaofeng, E-mail: wxftsjc@mail.ipe.ac.cn [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, 1 Zhongguancun Road, Haidian District 100190, Beijing (China); Chen, Yunfa, E-mail: yfchen@mail.ipe.ac.cn [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, 1 Zhongguancun Road, Haidian District 100190, Beijing (China); Boughton, R.I. [Department of Physics and Astronomy, Bowling Green State University, Bowling Green 43403, OH (United States)

    2014-02-01

    Highlights: • A simple synthesis of porous MgO with diameter size from 3 to 10 μm without any templates. • Effect of temperature and time were investigated. • Systematic characterization by TG/DTA, XRD, SEM, TEM, and nitrogen adsorption–desorption isotherm of MgO. • A possible formation and crystal growth mechanism of mesopores MgO is proposed. - Abstract: Mesoporous MgO particles have been synthesized through a novel template-free hydrothermal co-precipitation method using a Mg(NO{sub 3}){sub 2} solution as the magnesium source and NaCO{sub 3} as precipitant. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N{sub 2} adsorption–desorption analysis. The results indicate that the MgO samples have a disordered mesoporous structure, a large BET surface area, and a large pore volume. The effect of reaction temperature on the MgO product BET surface area was studied. A possible formation and crystal growth mechanism for mesoporous MgO is proposed.

  4. The synthesis and characterization of platinum nanoparticles: a method of controlling the size and morphology

    International Nuclear Information System (INIS)

    Long, Nguyen Viet; Hayakawa, Tomokatsu; Lakshminarayana, Gandham; Nogami, Masayuki; Chien, Nguyen Duc; Hirata, Hirohito

    2010-01-01

    In this paper, Pt nanoparticles with good shapes of nanocubes and nano-octahedra and well-controlled sizes in the range 5-7 and 8-12 nm, respectively, have been successfully synthesized. The modified polyol method by adding silver nitrate and varying the molar ratio of the solutions of silver nitrate and H 2 PtCl 6 has been used to produce Pt nanoparticles of the size and shape to be controlled. The size and morphology of Pt nanoparticles have been studied by transmission electron microscopy (TEM) and high resolution TEM (HRTEM). The results have shown that their very sharp and good shapes exist in the main forms of cubic, cuboctahedral, octahedral and tetrahedral shapes directly related to the crystal nucleation along various directions of the {100} cubic, {111} octahedral and {111} tetrahedral facets during synthesis. In particular, various irregular and new shapes of Pt nanoparticles have been found. Here, it is concluded that the role of silver ions has to be considered as an important factor for promoting and controlling the development of Pt nanoparticles of {100} cubic, {111} octahedral and {111} tetrahedral facets, and also directly orienting the growth and formation of Pt nanoparticles.

  5. The synthesis and characterization of platinum nanoparticles: a method of controlling the size and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Long, Nguyen Viet; Hayakawa, Tomokatsu; Lakshminarayana, Gandham; Nogami, Masayuki [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Chien, Nguyen Duc [Institute of Engineering Physics, Hanoi University of Technology, Dai Co Viet 1, Hanoi City (Viet Nam); Hirata, Hirohito, E-mail: nguyen.longviet@nitech.ac.jp, E-mail: nogami@nitech.ac.jp [Advanced Material Engineering Division, Toyota Motor Corporation, Higashifuji Technical Center 1200, Mishuku, Susono, Shizuoka (Japan)

    2010-01-22

    In this paper, Pt nanoparticles with good shapes of nanocubes and nano-octahedra and well-controlled sizes in the range 5-7 and 8-12 nm, respectively, have been successfully synthesized. The modified polyol method by adding silver nitrate and varying the molar ratio of the solutions of silver nitrate and H{sub 2}PtCl{sub 6} has been used to produce Pt nanoparticles of the size and shape to be controlled. The size and morphology of Pt nanoparticles have been studied by transmission electron microscopy (TEM) and high resolution TEM (HRTEM). The results have shown that their very sharp and good shapes exist in the main forms of cubic, cuboctahedral, octahedral and tetrahedral shapes directly related to the crystal nucleation along various directions of the {l_brace}100{r_brace} cubic, {l_brace}111{r_brace} octahedral and {l_brace}111{r_brace} tetrahedral facets during synthesis. In particular, various irregular and new shapes of Pt nanoparticles have been found. Here, it is concluded that the role of silver ions has to be considered as an important factor for promoting and controlling the development of Pt nanoparticles of {l_brace}100{r_brace} cubic, {l_brace}111{r_brace} octahedral and {l_brace}111{r_brace} tetrahedral facets, and also directly orienting the growth and formation of Pt nanoparticles.

  6. Synthesis and characterization of Cr2O3 nanoparticles through sol-gel proteic method

    International Nuclear Information System (INIS)

    Medeiros, Angela Maria de Lemos

    2007-01-01

    In the last years, nanoparticles have becoming important to several researchers. This research reside in the fact that new and uncommon physical and chemical properties, absent in the same material in macro and microscopic size, are observed in this new scale. The subject of this study is obtaining chromium oxide nanoparticles (Cr 2 O 3 ) by sol–gel proteic process using gelatin as an organic precursor. This process appears as a new alternative for the synthesis of oxides for great applications with high efficiency and low cost. The interest in that material is due to the several applications such as green pigments, coverings of materials for thermal protection and mainly as catalyst of countless products originating from of the industry of the petroleum, among others. This new route, using chromium salt as chromium source, produces nanoparticles with average particle size between 20 and 60nm. These values were obtained for different crystallographic direction by means of X-Ray Diffraction (XRD) technique and the structure refinement by Rietveld method were applied in several samples prepared at different temperatures. Other techniques have been used in order to complement the XRD results. (author)

  7. Vapour-phase method in the synthesis of polymer-ibuprofen sodium-silica gel composites

    Directory of Open Access Journals (Sweden)

    Agnieszka Kierys

    2017-11-01

    Full Text Available The study discusses the synthesis of polymer-silica composites comprising water soluble drug (ibuprofen sodium, IBS. The polymers selected for this study were poly(TRIM and poly(HEMA-co-TRIM produced in the form of permanently porous beads via the suspension-emulsion polymerization method. The acid and base set ternary composites were prepared by the saturation of the solid dispersions of drug (poly(TRIM-IBS and/or poly(HEMA-co-TRIM-IBS with TEOS, and followed by their exposition to the vapour mixture of water and ammonia, or water and hydrochloric acid, at autogenous pressure. The conducted analyses reveal that the internal structure and total porosity of the resulting composites strongly depend on the catalyst which was used for silica precursor gelation. The parameters characterizing the porosity of both of the acid set composites are much lower than the parameters of the base set composites. Moreover, the basic catalyst supplied in the vapour phase does not affect the ibuprofen sodium molecules, whereas the acid one causes transformation of the ibuprofen sodium into the sodium chloride and a derivative of propanoic acid, which is poorly water soluble. The release profiles of ibuprofen sodium from composites demonstrate that there are differences in the rate and efficiency of drug desorption from them. They are mainly affected by the chemical character of the polymeric carrier but are also associated with the restricted swelling of the composites in the buffer solution after precipitation of silica gel.

  8. Synthesis of Ag{sub 2}S nanorods by biomimetic method in the lysozyme matrix

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Dezhi, E-mail: dezhiqin@163.com; Zhang, Li; He, Guoxu; Zhang, Qiuxia

    2013-09-01

    Graphical abstract: - Highlights: • Firstly, Ag{sub 2}S nanorods were synthesized by biomimetic method in the lysozyme solutions. • The study of the interaction between Ag{sup +} and the lysozyme. • Discussion of possible formation mechanism of Ag{sub 2}S nanorods. • The synthesis process of lyso-conjugated Ag{sub 2}S nanocrystals is facile, effective and environment friendly. - Abstract: Ag{sub 2}S nanorods were successfully synthesized by biomimetic route in the lysozyme solution at physiological temperature and atmospheric pressure. The transmission electron microscopy (TEM) images revealed that the prepared nanorods are uniform and monodisperse with homogeneous size about 50 nm in diameter and 150 nm in length. The optical property of Ag{sub 2}S nanocrystals was studied by the ultraviolet–visible (UV–vis) and photoluminescence (PL) spectroscopy, the results show that the products exhibit well-defined emission at 471 nm and 496 nm excited by 292 nm. The interaction of Ag{sup +}/Ag{sub 2}S with the lysozyme was investigated through Fourier transform infrared (FT-IR) spectroscopy, which shows that the cooperation effect of the lysozyme and Ag{sup +} could be responsible for the formation of as obtained Ag{sub 2}S nanorods.

  9. Synthesis of ZnO-SiO2 nanocomposite particles and their characterization by sonochemical method

    Science.gov (United States)

    Widiyastuti, W.; Machmudah, Siti; Nurtono, Tantular; Winardi, Sugeng; Okuyama, Kikuo

    2017-05-01

    ZnO-SiO2 nanocomposite particles were prepared by sonochemical method under continuous ultrasound irradiation for an hour. Zinc nitrate and sodium silicate were used as zinc oxide and silica sources, respectively. Silica concentration was varied to investigate the effect of silica on the characteristics of the generated composite particles and they were also compared to ZnO particles. Morphology, crystallinity, chemical bonding analysis, photoluminescence spectra, and photocatalytic activity were characterized by scanning electron microscopy (SEM), X-Ray diffraction, Fourier Transform Infrared (FTIR), luminescence spectrophotometer, and UV-Vis spectrophotometer, respectively. Nanorod structures were observed for pure ZnO, ZnO-SiO2 particles with 250 ppm and 750 ppm silica addition during synthesis. Spherical agglomerated particles were found for particle with 0.1 M silica addition. The crystalline size and photocalytic activity decreased with the silica addition. A strongest chemical bonding for ZnO and SiO2 was also observed for particle with 0.1 M silica addition based on FTIR spectra. However, the highest photoluminescence emission by excitation wavelength at 250 nm, was observed for ZnO-SiO2 particles with 750 ppm silica addition with emission peak at 515 nm wavelength.

  10. Effect of synthesis conditions on the preparation of YIG powders via co-precipitation method

    International Nuclear Information System (INIS)

    Rashad, M.M.; Hessien, M.M.; El-Midany, A.; Ibrahim, I.A.

    2009-01-01

    Yttrium iron garnet (YIG) (Y 3 Fe 5 O 12 ) powders have been synthesized through a co-precipitation method in the presence of sodium bis(2-ethylhexylsulfosuccinate), AOT as an anionic surfactant. The garnet precursors produced were obtained from aqueous iron and yttrium nitrates mixtures using 5 M sodium hydroxide at pH 10. A statistical Box-Behnken experimental design was used to investigate the effect of the main parameters (i.e. AOT surfactant concentration, annealing time and temperature) on YIG powder formation, crystallite size, morphology and magnetic properties. YIG particles were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer. XRD revealed that the formation of single cubic phase of YIG was temperature dependent and increased by increasing the annealing temperature from 800 to 1200 o C. SEM micrographs showed that the addition of AOT surfactant promoted the microstructure of YIG in crystalline cubic-like structure. The magnetic properties were sensitive to the synthesis variables of annealing temperature, time and AOT surfactant concentration. The maximum saturation magnetization (28.13 emu/g), remanence magnetization (21.57 emu/g) and coercive force (703 Oe) were achieved at an annealing temperature of 1200 o C, time 2 h and 500 ppm of AOT surfactant concentration.

  11. Synthesis of zinc oxide by microwave hydrothermal method for application to transesterification of soybean oil (biodiesel)

    Energy Technology Data Exchange (ETDEWEB)

    Quirino, Max Rocha [LABQUIM/Universidade Federal da Paraíba, Campus III, 58200-000, Bananeiras, PB (Brazil); Oliveira, Mateus José C. [DEMA/Universidade Federal de Campina Grande, Campina Grande, Campus I, 58429-900, Campina Grande, PB (Brazil); Keyson, Davy [DME/Universidade Federal da Paraíba, Campus – I, 58051-900, João Pessoa, PB (Brazil); Lucena, Guilherme Leocárdio, E-mail: guilhermelucena@cchsa.ufpb.br [LABQUIM/Universidade Federal da Paraíba, Campus III, 58200-000, Bananeiras, PB (Brazil); Oliveira, João Bosco L. [Universidade Federal do Rio Grande do Norte, Campus I, 59078-970, Natal, RN (Brazil); Gama, Lucianna [DEMA/Universidade Federal de Campina Grande, Campina Grande, Campus I, 58429-900, Campina Grande, PB (Brazil)

    2017-01-01

    ZnO nanostructures were synthesized by microwave hydrothermal treatment using two different mineralization agents (NaOH and NH{sub 4}OH), and were evaluated as catalysts for biodiesel synthesis. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. The XRD patterns indicated the formation of the hexagonal wurtzite phase in both samples. SEM analysis showed completely different morphologies based on the mineralization agent employed. The ZnO nanostructures synthesized with NaOH (ZONa5 and ZONa5P) presented plate-like agglomerates, resulting in a quasi-spherical morphology, whereas the materials synthesized with NH{sub 4}OH (ZONH5 and ZONH5P) presented a flower-like morphology. The ZONa5P sample showed an activity of 77.82% for the catalytic conversion of soybean oil into biodiesel by transesterification using methanol. - Highlights: • ZnO was synthesized by MH method in only 5 min. • The powders morphology is completely influenced by mineralization agent. • ZONa5P showed activity of 77.82% for the conversion of soybean oil into biodiesel.

  12. Synthesis and characterization of nanostructured zinc oxide particles synthesized by the pyrosol method

    Science.gov (United States)

    Vasile, Otilia-Ruxandra; Andronescu, Ecaterina; Ghitulica, Cristina; Vasile, Bogdan Stefan; Oprea, Ovidiu; Vasile, Eugeniu; Trusca, Roxana

    2012-12-01

    Nanostructured ZnO particles with different crystallite dimensions, in the range between 5.7 and 21.8 nm, with poly-crystalline structure, have been obtained, in a facile manner, using the pyrosol method. The microstructure and properties of the obtained powders were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) with selected area electron diffraction and fluorescence spectroscopy. From the XRD spectra it was observed that, starting from 600 °C, zinc oxide with wurtzite structure is obtained. The particles have spherical morphology, as it can be seen from SEM images, with an average particle size ranging from 0.2 to 2 μm. The TEM analysis reveals that the particles are in fact agglomerates, nanostructured, with an average nanoparticles size as low as 13.9 nm. The composition, morphology and size of obtained particles are influenced by the synthesis temperatures, as well as by the concentration of precursor solutions.

  13. Application of Model-Checking Technology to Controller Synthesis

    DEFF Research Database (Denmark)

    David, Alexandre; Grunnet, Jacob Deleuran; Jessen, Jan Jacob

    2011-01-01

    In this paper we present two frameworks that have been implemented to link traditional model-checking techniques to the domain of control. The techniques are based on solving a timed game and using the resulting solution (a strategy) as a controller. The obtained discrete controller must fit with...

  14. Synthesis and Analytical Centrifugation of Magnetic Model Colloids

    NARCIS (Netherlands)

    Luigjes, B.

    2012-01-01

    This thesis is a study of the preparation and thermodynamic properties of magnetic colloids. First, two types of magnetic model colloids are investigated: composite colloids and single-domain nanoparticles. Thermodynamics of magnetic colloids is studied using analytical centrifugation, including a

  15. Modelling, Synthesis, and Configuration of Networks-on-Chips

    DEFF Research Database (Denmark)

    Stuart, Matthias Bo

    is an analytical method for deriving the worst-case traffic pattern caused by an application and the cache-coherence protocol in a cache-coherent shared-memory system. The contributions related to network-on-chip optimization problems consist of two parts: The development and evaluation of six heuristics...

  16. Robustness in Escherichia coli Glutamate and Glutamine Synthesis Studied by a Kinetic Model

    OpenAIRE

    Lodeiro, Aníbal; Melgarejo, Augusto

    2008-01-01

    Metabolic control of glutamine and glutamate synthesis from ammonia and oxoglutarate in Escherichia coli is tight and complex. In this work, the role of glutamine synthetase (GS) and glutamate dehydrogenase (GDH) regulation in this control was studied. Both enzymes form a linear pathway, which can also have a cyclic topology if glutamate–oxoglutarate amino transferase (GOGAT) activity is included. We modelled the metabolic pathways in the linear or cyclic topologies using a coupled nonlinear...

  17. Mathematical Modeling Applied Transesterification Reaction Product of Synthesis from Animal Fats and Vegetable Oil

    OpenAIRE

    Letícia Thaís Chendynski; Universidade Estadual de Londrina; Karina G. Angilelli; Universidade Estadual de Londrina; Bruna A. D. Ferreira; Unversidade Esadual de Londrina; Dionisio Borsato; Universidade Estadual de Londrina

    2009-01-01

    The high availability and low cost of animal fat have promoted industrial interest as a partial substitute for soybean oil for transesterification reaction product of synthesis, to reduce costs and maximize profits. This study aimed to apply experimental design for biodiesel production from a mixture of soybean oil, poultry fat, beef tallow and pork lard in order to obtain predictive equations to model the transesterification reaction yield, cloud point, pour point and oxidative stability, wi...

  18. Functional Brain Imaging Synthesis Based on Image Decomposition and Kernel Modeling: Application to Neurodegenerative Diseases

    Science.gov (United States)

    Martinez-Murcia, Francisco J.; Górriz, Juan M.; Ramírez, Javier; Illán, Ignacio A.; Segovia, Fermín; Castillo-Barnes, Diego; Salas-Gonzalez, Diego

    2017-01-01

    The rise of neuroimaging in research and clinical practice, together with the development of new machine learning techniques has strongly encouraged the Computer Aided Diagnosis (CAD) of different diseases and disorders. However, these algorithms are often tested in proprietary datasets to which the access is limited and, therefore, a direct comparison between CAD procedures is not possible. Furthermore, the sample size is often small for developing accurate machine learning methods. Multi-center initiatives are currently a very useful, although limited, tool in the recruitment of large populations and standardization of CAD evaluation. Conversely, we propose a brain image synthesis procedure intended to generate a new image set that share characteristics with an original one. Our system focuses on nuclear imaging modalities such as PET or SPECT brain images. We analyze the dataset by applying PCA to the original dataset, and then model the distribution of samples in the projected eigenbrain space using a Probability Density Function (PDF) estimator. Once the model has been built, we can generate new coordinates on the eigenbrain space belonging to the same class, which can be then projected back to the image space. The system has been evaluated on different functional neuroimaging datasets assessing the: resemblance of the synthetic images with the original ones, the differences between them, their generalization ability and the independence of the synthetic dataset with respect to the original. The synthetic images maintain the differences between groups found at the original dataset, with no significant differences when comparing them to real-world samples. Furthermore, they featured a similar performance and generalization capability to that of the original dataset. These results prove that these images are suitable for standardizing the evaluation of CAD pipelines, and providing data augmentation in machine learning systems -e.g. in deep learning-, or even to

  19. Functional Brain Imaging Synthesis Based on Image Decomposition and Kernel Modeling: Application to Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Francisco J. Martinez-Murcia

    2017-11-01

    Full Text Available The rise of neuroimaging in research and clinical practice, together with the development of new machine learning techniques has strongly encouraged the Computer Aided Diagnosis (CAD of different diseases and disorders. However, these algorithms are often tested in proprietary datasets to which the access is limited and, therefore, a direct comparison between CAD procedures is not possible. Furthermore, the sample size is often small for developing accurate machine learning methods. Multi-center initiatives are currently a very useful, although limited, tool in the recruitment of large populations and standardization of CAD evaluation. Conversely, we propose a brain image synthesis procedure intended to generate a new image set that share characteristics with an original one. Our system focuses on nuclear imaging modalities such as PET or SPECT brain images. We analyze the dataset by applying PCA to the original dataset, and then model the distribution of samples in the projected eigenbrain space using a Probability Density Function (PDF estimator. Once the model has been built, we can generate new coordinates on the eigenbrain space belonging to the same class, which can be then projected back to the image space. The system has been evaluated on different functional neuroimaging datasets assessing the: resemblance of the synthetic images with the original ones, the differences between them, their generalization ability and the independence of the synthetic dataset with respect to the original. The synthetic images maintain the differences between groups found at the original dataset, with no significant differences when comparing them to real-world samples. Furthermore, they featured a similar performance and generalization capability to that of the original dataset. These results prove that these images are suitable for standardizing the evaluation of CAD pipelines, and providing data augmentation in machine learning systems -e.g. in deep

  20. Inhibiting corticosterone synthesis during fear memory formation exacerbates cued fear extinction memory deficits within the single prolonged stress model.

    Science.gov (United States)

    Keller, Samantha M; Schreiber, William B; Stanfield, Briana R; Knox, Dayan

    2015-01-01

    Using the single prolonged stress (SPS) animal model of post-traumatic stress disorder (PTSD), previous studies suggest that enhanced glucocorticoid receptor (GR) expression leads to cued fear extinction retention deficits. However, it is unknown how the endogenous ligand of GRs, corticosterone (CORT), may contribute to extinction retention deficits in the SPS model. Given that CORT synthesis during fear learning is critical for fear memory consolidation and SPS enhances GR expression, CORT synthesis during fear memory formation could strengthen fear memory in SPS rats by enhancing GR activation during fear learning. In turn, this could lead to cued fear extinction retention deficits. We tested the hypothesis that CORT synthesis during fear learning leads to cued fear extinction retention deficits in SPS rats by administering the CORT synthesis inhibitor metyrapone to SPS and control rats prior to fear conditioning, and observed the effect this had on extinction memory. Inhibiting CORT synthesis during fear memory formation in control rats tended to decrease cued freezing, though this effect never reached statistical significance. Contrary to our hypothesis, inhibiting CORT synthesis during fear memory formation disrupted extinction retention in SPS rats. This finding suggests that even though SPS exposure leads to cued fear extinction memory deficits, CORT synthesis during fear memory formation enhances extinction retention in SPS rats. This suggests that stress-induced CORT synthesis in previously stressed rats can be beneficial. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Synthesis, Characterization, and Atenolol Delivery Application of Functionalized Mesoporous Hydroxyapatite Nanoparticles Prepared by Microwave-Assisted Co-precipitation Method.

    Science.gov (United States)

    Mortazavi-Derazkola, Sobhan; Naimi-Jamal, Mohammad Reza; Ghoreishi, Seyedeh Masoumeh

    2016-01-01

    Atenolol has been used to treat angina and hypertension, either alone or with other antihypertensives. Despite its usefulness, it shows some side effects such as diarrhea and nausea in some patients. A method for slow release of atenolol in intestine is helpful to prevent such side effects. A facile co-precipitation microwave-assisted method was used to fabricate mesoporous hydroxyapatite nanoparticles (mHAp). It was then functionalized to have SO3H groups. The synthesized material was used for storage/slow release study of atenolol. Atenolol loaded mHAp shows immediate release of atenolol in pH 8, whileafter functionalizing shows up to ca. 30% release at the beginning. In pH 1, 50% of drug was released after 10 h from AT@mHAp and after 18h the drug was almost completely released.The drug release profiles of functionalized HAp at pH value 1 and 8reveals the complete release of atenolol in intestine pH, while no complete release is observed in stomach environment. The aims of this work were synthesis and characterization of mesoporous HAp through the microwave-assisted co-precipitation method and elucidate the underlying drug release capability of mesoporous HAp nanoparticles. The SO3H group was incorporated into the mesoporous HAp and then used as drug delivery carriers using atenolol as a model drug to investigate their drug storage/release properties in simulated body fluid (SBF). Increasing pH value to 8 causes increase in the drug release.

  2. Computer-Aided Modelling Methods and Tools

    DEFF Research Database (Denmark)

    Cameron, Ian; Gani, Rafiqul

    2011-01-01

    . To illustrate these concepts a number of examples are used. These include models of polymer membranes, distillation and catalyst behaviour. Some detailed considerations within these models are stated and discussed. Model generation concepts are introduced and ideas of a reference model are given that shows...

  3. GREENSCOPE: A Method for Modeling Chemical Process ...

    Science.gov (United States)

    Current work within the U.S. Environmental Protection Agency’s National Risk Management Research Laboratory is focused on the development of a method for modeling chemical process sustainability. The GREENSCOPE methodology, defined for the four bases of Environment, Economics, Efficiency, and Energy, can evaluate processes with over a hundred different indicators. These indicators provide a means for realizing the principles of green chemistry and green engineering in the context of sustainability. Development of the methodology has centered around three focal points. One is a taxonomy of impacts that describe the indicators and provide absolute scales for their evaluation. The setting of best and worst limits for the indicators allows the user to know the status of the process under study in relation to understood values. Thus, existing or imagined processes can be evaluated according to their relative indicator scores, and process modifications can strive towards realizable targets. A second area of focus is in advancing definitions of data needs for the many indicators of the taxonomy. Each of the indicators has specific data that is necessary for their calculation. Values needed and data sources have been identified. These needs can be mapped according to the information source (e.g., input stream, output stream, external data, etc.) for each of the bases. The user can visualize data-indicator relationships on the way to choosing selected ones for evalua

  4. Epidemic meningococcal disease: synthesis of a hypothetical immunoepidemiologic model.

    Science.gov (United States)

    Griffiss, J M

    1982-01-01

    A hypothetical model of the epidermic behavior of Neisseria meningitidis, based upon the induction of susceptibility to disseminated disease by circulating IgA, is presented. The model is based on the assumption that epidemic susceptibility is acquired as a result of induction of serum IgA by cross-reacting enteric bacteria, the priming organism. Co-colonization with the appropriate strain of N. meningitidis then may result in disseminated disease. Colonization by either bacterium in the absence of the other results in reinforcement of the commensal relationship. Slow, silent, fecal-oral transmission of the priming organism determines the time/space characteristics of an epidemic; interruption of fecal-oral transmission aborts it. Aerosol transmission of the meningococcus determines the magnitude of an epidemic. Independent, age-related acquisition of both capsular polysaccharide and lipopolysaccharide antibodies provides immunity in the absence of aberrantly high levels of co-specific serum IgA.

  5. A CATALYTIC METHOD FOR THE SYNTHESIS OF 4-ALKYL(ARYL ...

    African Journals Online (AJOL)

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    )-pyridinones and their 2-imino ... synthesis of milrinone analogues as a series of nonglycosidic, non-sympathomimetic, cardiotonic .... from dimethoxyacetophenone and ammonia adds to the aldol condensation product of the aldehyde and ...

  6. Dual wavelength asymmetric photochemical synthesis with circularly polarized light† †Electronic supplementary information (ESI) available: Full detailed methods used for the entire study; further discussion of the work not central to the main message of the paper; full derivation of the kinetics models used to predict the dual wavelength enantioselectivity; computational details and energy breakdown; more complete mechanism for the reaction. See DOI: 10.1039/c4sc03897e

    Science.gov (United States)

    Richardson, Robert D.; Baud, Matthias G. J.; Weston, Claire E.; Rzepa, Henry S.

    2015-01-01

    Asymmetric photochemical synthesis using circularly polarized (CP) light is theoretically attractive as a means of absolute asymmetric synthesis and postulated as an explanation for homochirality on Earth. Using an asymmetric photochemical synthesis of a dihydrohelicene as an example, we demonstrate the principle that two wavelengths of CP light can be used to control separate reactions. In doing so, a photostationary state (PSS) is set up in such a way that the enantiomeric induction intrinsic to each step can combine additively, significantly increasing the asymmetric induction possible in these reactions. Moreover, we show that the effects of this dual wavelength approach can be accurately determined by kinetic modelling of the PSS. Finally, by coupling a PSS to a thermal reaction to trap the photoproduct, we demonstrate that higher enantioselectivity can be achieved than that obtainable with single wavelength irradiation, without compromising the yield of the final product. PMID:29218156

  7. The mathematical model structural-parametric synthesis of working processes in an oxygen-methane steam generator with flow swirl

    Science.gov (United States)

    Timoshinova, T. S.; Shmatov, D. P.; Kretinin, A. V.; Drozdov, I. G.

    2017-11-01

    While formulating a mathematical model of the flow and interaction between oxygen-methane fuel combustion products with tangentially swirled ballast water injected in the end of the combustion chamber in CAE product Fluent, which integrated into the ANSYS Workbench platform, the problem of structural-parametric synthesis is solved for structure optimization of the model. Equations are selected from the catalogue of Fluent physical models. Also optimization helps to find “regime” model parameters that determine the specific implementation of the model inside the synthesized structure. As a result, such solutions which were developed during creation of a numerical algorithm, as the choice of a turbulence model and the state equation, the methods for determining the thermodynamic thermophysical characteristics of combustion products, the choice of the radiation model, the choice of the resistance law for drops, the choice of the expression which allows to evaluate swirling flows lateral force, determination of the turbulent dispersion strength, choice of the mass exchange law, etc. Fields of temperature, pressure, velocity and volume fraction of phases were obtained at different ballast water mass flows. Dependence of wall temperature from mass flow of ballast water is constructed, that allows us to compare results of the experiment and mathematical modeling.

  8. The synthesis of Ag/polypyrrole coaxial nanocables via ion adsorption method using different oxidants

    International Nuclear Information System (INIS)

    Qiu Teng; Xie Huxiao; Zhang Jiangru; Zahoor, Amad; Li Xiaoyu

    2011-01-01

    Ag/polypyrrole (PPy) coaxial nanocables (NCs) were synthesized by an ion adsorption method. In this method, the pre-made Ag nanowires (NWs) were dispersed in the aqueous solution of copper acetate (Cu(Ac) 2 ), and the Cu 2+ ions adsorbed onto the surface of Ag NWs can oxidize pyrrole monomers to polymerize into uniform PPy sheath outside Ag NWs after the Cu(Ac) 2 -treated Ag NWs were re-dispersed in the aqueous solution of pyrrole. The morphology of NCs was characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). The relationship between the thickness of polymer sheath and the concentration of Cu(Ac) 2 was established. As Cu(Ac) 2 which served as the oxidant can also be replaced by AgNO 3 in this synthesis, the differences on the structure of polymer sheath caused by different oxidants were studied by surface-enhanced Raman scattering (SERS), high-resolution transmission electron microscope (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Comparing with the characterization results of Ag/PPy NCs synthesized using AgNO 3 as the oxidant which indicates the random arrangement of PPy chains at the interface between polymer sheath and Ag NWs, PPy chain oxidized by Cu 2+ tends to show a relatively ordered conformation at the interface with the pyrrole rings identically taking the plane vertical to the surface of Ag NWs. In addition, although the main part of the polymer sheath was composed of PPy whatever kind of oxidant was used, the sheath of the NCs oxidized by Cu 2+ is typical for the existence of Cu(I)–pyrrole coordinate structures with strong Cu(I)–N bond signal shown in XPS characterization.

  9. YIG based broad band microwave absorber: A perspective on synthesis methods

    Science.gov (United States)

    Sharma, Vinay; Saha, J.; Patnaik, S.; Kuanr, Bijoy K.

    2017-10-01

    The fabrication of a thin layer of microwave absorber that operates over a wide band of frequencies is still a challenging task. With recent advances in nanostructure synthesis techniques, considerable progress has been achieved in realizations of thin nanocomposite layer designed for full absorption of incident electromagnetic (EM) radiation covering S to K band frequencies. The primary objective of this investigation is to achieve best possible EM absorption with a wide bandwidth and attenuation >10 dB for a thin absorbing layer (few hundred of microns). Magnetic yttrium iron garnet (Y3Fe5O12; in short YIG) nanoparticles (NPs) were prepared by sol-gel (SG) as well as solid-state (SS) reaction methods to elucidate the effects of nanoscale finite size on the magnetic behavior of the particles and hence their microwave absorption capabilities. It is found that YIG prepared by these two methods are different in many ways. Magnetic properties investigated using vibrating sample magnetometry (VSM) exhibit that the coercivity (Hc) of solid-state NPs is much larger (72 Oe) than the sol-gel NPs (31 Oe). Microwave absorption properties were studied by ferromagnetic resonance (FMR) technique in field sweep mode at different fixed frequencies. A thin layer (∼300 μm) of YIG film was deposited using electrophoretic deposition (EPD) technique over a coplanar waveguide (CPW) transmission line made on copper coated RT/duroid® 5880 substrates. Temperature dependent magnetic properties were also investigated using VSM and FMR techniques. Microwave absorption properties were investigated at high temperatures (up to 300 °C) both for sol-gel and solid-state synthesized NPs and are related to skin depth of YIG films. It is observed that microwave absorption almost vanishes when the temperature reached the Néel temperature of YIG.

  10. Security giving in surrogacy motherhood process as a caring model for commissioning mothers: A theory synthesis.

    Science.gov (United States)

    Zandi, Mitra; Vanaki, Zohreh; Shiva, Marziyeh; Mohammadi, Eesa; Bagheri-Lankarani, Narges

    2016-07-01

    Despite the increasing use of surrogacy, there are no caring theories/models that serve as the basis for nursing care to surrogacy commissioning mothers. This study has designed a model for caring of surrogacy commissioning mothers in 2013. The theory synthesis of Walker and Avant's strategies of theory construction (2011) was used to design a caring model/theory. The theory synthesis includes three stages: (i) selection of focal concept (the concept of "security giving in motherhood" was selected); (ii) review of studies in order to identify factors related to focal concept relevant studies (42 articles and 13 books) were reviewed, statements and concepts related to focal concept were then extracted and classified, and their relations were specified; and (iii) organization of concepts and statements within a relevant general and effective manifestation of the phenomenon under study which led to developing of a model. In this caring model/theory, entitled "security giving in surrogacy motherhood", nurses roles were conceptualized within the conceptual framework that includes three main roles: (i) coordination; (ii) participation; and (iii) security giving (physical, emotional, and legal support; empowerment; presence; relationship management between both parties and advocacy). Training surrogacy specialist nurses and establishment of surrogacy care centers are important factors for implementation of the model. This model could help to provided better caring for surrogacy clients, especially for commissioning mothers. © 2016 Japan Academy of Nursing Science.

  11. Synthesis of audio spectra using a diffraction model.

    Science.gov (United States)

    Vijayakumar, V; Eswaran, C

    2006-12-01

    It is shown that the intensity variations of an audio signal in the frequency domain can be obtained by using a mathematical function containing a series of weighted complex Bessel functions. With proper choice of values for two parameters, this function can transform an input spectrum of discrete frequencies of unit intensity into the known spectra of different musical instruments. Specific examples of musical instruments are considered for evaluating the performance of this method. It is found that this function yields musical spectra with a good degree of accuracy.

  12. Comparison among structural characteristics of Ce1-xCuxO2 nanocatalysts obtained by two methods of distinct synthesis

    International Nuclear Information System (INIS)

    Neiva, L.S.; Bispo, A.; Santos, P.T.A.; Costa, A.C.F.M.; Gama, L.; Mascarenhas, A.J.S.

    2009-01-01

    The objective this work is to synthesize nano catalysts Ce 1-x Cu x O 2 type by the synthesis methods of the combustion reaction and Pechini. The value of the concentration (x) of the element dope (Cu) varies between 0,1 and 0,5 mols. It intends evaluate that form the synthesis method influences in the physical structural characteristics of this material. nano catalysts were characterized by ray- X diffraction. The results showed nano catalysts formation with a formed structure for the most part by the phase CeO 2 , as it was expected, since this is the hostess matrix of the element dope (Cu). Nano catalysts obtained by the method Pechini presents crystallinity larger deg, according with patterns of ray-X. Thus, it was concluded that synthesis employee method the kind in the methodology, as well as the value of the concentration of the element dope has influence on the final structural characteristics of the developed material. (author)

  13. Aerobic method for the synthesis of nearly size-monodisperse bismuth nanoparticles from a redox non-innocent precursor

    Science.gov (United States)

    Winter, H.; Christopher-Allison, E.; Brown, A. L.; Goforth, A. M.

    2018-04-01

    Herein, we report an aerobic synthesis method to produce bismuth nanoparticles (Bi NPs) with average diameters in the range 40-80 nm using commercially available bismuth triiodide (BiI3) as the starting material; the method uses only readily available chemicals and conventional laboratory equipment. Furthermore, size data from replicates of the synthesis under standard reaction conditions indicate that this method is highly reproducible in achieving Bi NP populations with low standard deviations in the mean diameters. We also investigated the mechanism of the reaction, which we determined results from the reduction of a soluble alkylammonium iodobismuthate precursor species formed in situ. Under appropriate concentration conditions of iodobismuthate anion, we demonstrate that burst nucleation of Bi NPs results from reduction of Bi3+ by the coordinated, redox non-innocent iodide ligands when a threshold temperature is exceeded. Finally, we demonstrate phase transfer and silica coating of the Bi NPs, which results in stable aqueous colloids with retention of size, morphology, and colloidal stability. The resultant, high atomic number, hydrophilic Bi NPs prepared using this synthesis method have potential for application in emerging x-ray contrast and x-ray therapeutic applications.

  14. Model reduction methods for vector autoregressive processes

    CERN Document Server

    Brüggemann, Ralf

    2004-01-01

    1. 1 Objective of the Study Vector autoregressive (VAR) models have become one of the dominant research tools in the analysis of macroeconomic time series during the last two decades. The great success of this modeling class started with Sims' (1980) critique of the traditional simultaneous equation models (SEM). Sims criticized the use of 'too many incredible restrictions' based on 'supposed a priori knowledge' in large scale macroeconometric models which were popular at that time. Therefore, he advo­ cated largely unrestricted reduced form multivariate time series models, unrestricted VAR models in particular. Ever since his influential paper these models have been employed extensively to characterize the underlying dynamics in systems of time series. In particular, tools to summarize the dynamic interaction between the system variables, such as impulse response analysis or forecast error variance decompo­ sitions, have been developed over the years. The econometrics of VAR models and related quantities i...

  15. A business case method for business models

    NARCIS (Netherlands)

    Meertens, Lucas Onno; Starreveld, E.; Iacob, Maria Eugenia; Nieuwenhuis, Lambertus Johannes Maria; Shishkov, Boris

    2013-01-01

    Intuitively, business cases and business models are closely connected. However, a thorough literature review revealed no research on the combination of them. Besides that, little is written on the evaluation of business models at all. This makes it difficult to compare different business model

  16. SYNTHESIS OF 2,6-DIAMINOPYRIDINE-4-NITROPHENOL (2,6DAP4N COCRYSTAL NANOPARTICLES BY LASER ABLATION METHOD

    Directory of Open Access Journals (Sweden)

    N. A. Zulina

    2015-11-01

    Full Text Available We propose findings for laser ablation of organic materials in liquids as one of the perspective methods of nanoparticles synthesis on their basis. We describe nanoparticles synthesis for 2,6-diaminopyridine-4-nitrophenol (2,6DAP4N cocrystal by the method of material laser ablation at nanoparticles condensation in liquid (dodecane and polyphenyleneoxide. Laser radiation with wavelength equal to 355 nm, pulse duration - 10 ns, pulse repetition rate - 3.8 kHz, and pulse power density equal to 170 kW/cm2 has been used in the study. Nanoparticles in the form of colloids have been obtained and studied by visible range spectroscopy and optical microscopy. Obtained particles size is around 0.5 μm.

  17. Synthesis, sintering and dissolution of thorium and uranium (IV) mixed oxide solid solutions: influence of the method of precursor preparation

    International Nuclear Information System (INIS)

    Hingant, N.

    2008-12-01

    Mixed actinide dioxides are currently considered as potential fuels for the third and fourth generations of nuclear reactors. In this context, thorium-uranium (IV) dioxide solid solutions were studied as model compounds to underline the influence of the method of preparation on their physico-chemical properties. Two methods of synthesis, both based on the initial precipitation of oxalate precursors have been developed. The first consisted in the direct precipitation ('open' system) while the second involved hydrothermal conditions ('closed' system). The second method led to a significant improvement in the crystallization of the samples especially in the field of the increase of the grain size. In these conditions, the formation of a complete solid solution Th 1-x U x (C 2 O 4 ) 2 .2H 2 O was prepared between both end-members. Its crystal structure was also resolved. Whatever the initial method considered, these compounds led to the final dioxides after heating above 400 C. The various steps associated to this transformation, involving the dehydration of precursors then the decomposition of oxalate groups have been clarified. Moreover, the use of wet chemistry methods allowed to reduce the sintering temperature of the final thorium-uranium (IV) dioxide solid solutions. Whatever the method of preparation considered, dense samples (95% to 97% of the calculated value) were obtained after only 3 hours of heating at 1500 C. Additionally, the use of hydrothermal conditions significantly increased the grain size, leading to the reduction of the occurrence of the grain boundaries and of the global residual porosity. The significant improvement in the homogeneity of cations distribution in the samples was also highlighted. Finally, the chemical durability of thorium-uranium (IV) dioxide solid solutions was evaluated through the development of leaching tests in nitric acid. The optimized homogeneity especially in terms of the cations distribution, allowed to limit the

  18. Green Synthesis of Ultraviolet Absorber 2-Ethylhexyl Salicylate: Experimental Design and Artificial Neural Network Modeling

    Directory of Open Access Journals (Sweden)

    Shang-Ming Huang

    2017-11-01

    Full Text Available 2-Ethylhexyl salicylate, an ultraviolet filter, is widely used to protect skin against sunlight-induced harmful effects in the cosmetic industry. In this study, the green synthesis of 2-ethylhexyl salicylate using immobilized lipase through a solvent-free and reduced pressure evaporation system was investigated. A Box–Behnken design was employed to develop an artificial neural network (ANN model. The parameters for an optimal architecture of an ANN were set out: a quick propagation algorithm, a hyperbolic tangent transfer function, 10,000 iterations, and six nodes within the hidden layer. The best-fitting performance of the ANN was determined by the coefficient of determination and the root-mean-square error between the correlation of predicted and experimental data, indicating that the ANN displayed excellent data-fitting properties. Finally, the experimental conditions of synthesis were well established with the optimal parameters to obtain a high conversion of 2-ethylhexyl salicylate. In conclusion, this study efficiently replaces the traditional solvents with a green process for the synthesis of 2-ethylhexyl salicylate to avoid environmental contamination, and this process is well-modeled by a methodological ANN for optimization, which might be a benefit for industrial production.

  19. Real-Time Gesture-Controlled Physical Modelling Music Synthesis with Tactile Feedback

    Directory of Open Access Journals (Sweden)

    David M. Howard

    2004-06-01

    Full Text Available Electronic sound synthesis continues to offer huge potential possibilities for the creation of new musical instruments. The traditional approach is, however, seriously limited in that it incorporates only auditory feedback and it will typically make use of a sound synthesis model (e.g., additive, subtractive, wavetable, and sampling that is inherently limited and very often nonintuitive to the musician. In a direct attempt to challenge these issues, this paper describes a system that provides tactile as well as acoustic feedback, with real-time synthesis that invokes a more intuitive response from players since it is based upon mass-spring physical modelling. Virtual instruments are set up via a graphical user interface in terms of the physical properties of basic well-understood sounding objects such as strings, membranes, and solids. These can be interconnected to form complex integrated structures. Acoustic excitation can be applied at any point mass via virtual bowing, plucking, striking, specified waveform, or from any external sound source. Virtual microphones can be placed at any point masses to deliver the acoustic output. These aspects of the instrument are described along with the nature of the resulting acoustic output.

  20. Application of the single-channel continuous synthesis method to criticity and power distribution calculations in thermal reactors

    International Nuclear Information System (INIS)

    Medrano Asensio, Gregorio.

    1976-06-01

    A detailed power distribution calculation in a large power reactor requires the solution of the multigroup 3D diffusion equations. Using the finite difference method, this computation is too expensive to be performed for design purposes. This work is devoted to the single channel continous synthesis method: the choice of the trial functions and the determination of the mixing functions are discussed in details; 2D and 3D results are presented. The method is applied to the calculation of the IAEA ''Benchmark'' reactor and the results obtained are compared with a finite element resolution and with published results [fr

  1. A facile, green and efficient surfactant-free method for synthesis of aluminum nanooxides with an extraordinary high surface area.

    Science.gov (United States)

    Mohammadnezhad, Gholamhossein; Akintola, Oluseun; Plass, Winfried; Steiniger, Frank; Westermann, Martin

    2016-04-21

    Nano boehmite with unprecedented high surface area and pore volume (802 m(2) g(-1), 2.35 cm(3) g(-1)) was prepared using a facile, green and efficient surfactant-free synthesis method. The structure of the material is characterized by the presence of plates with varying thicknesses and morphologies. The calcined samples show curved and rolled plates with a nanotube-like appearance.

  2. Exemplar-based Parametric Hidden Markov Models for Recognition and Synthesis of Movements

    DEFF Research Database (Denmark)

    Herzog, Dennis; Krüger, Volker; Grest, Daniel

    2007-01-01

    A common problem in movement recognition is the recognition of movements of a particular type. E.g. pointing movements are of a particular type but differ in terms of the pointing direction. Arm movements with the goal of reaching out and grasping an object are of a particular type but differ...... with the location of the involved object. In this paper, we present an exemplar-based parametric hidden Markov model (PHMM) that is able to recognize and synthesize movements of a particular type. The PHMM is based on exemplar movements that have to be ``demonstrated'' to the system. Recognition and synthesis...... are carried out through locally linear interpolation of the exemplar movements. Experiments are performed with pointing and grasping movements. Synthesis is done based on the object position as parameterization. In case of the recognition, the coordinates of the grasped or pointed at object are recovered. Our...

  3. System-Level Modeling and Synthesis of Flow-Based Microfluidic Biochips

    DEFF Research Database (Denmark)

    Minhass, Wajid Hassan; Pop, Paul; Madsen, Jan

    2011-01-01

    Microfluidic biochips are replacing the conventional biochemical analyzers and are able to integrate the necessary functions for biochemical analysis on-chip. There are several types of microfluidic biochips, each having its advantages and limitations. In this paper we are interested in flow......-based biochips, in which the flow of liquid is manipulated using integrated microvalves. By combining several microvalves, more complex units, such as micropumps, switches, mixers, and multiplexers, can be built. Although researchers have proposed significant work on the system-level synthesis of droplet......-based biochips, which manipulate droplets on a two-dimensional array of electrodes, no research on system-level synthesis of flow-based biochips has been reported so far. The focus has been on application modeling and component-level simulation. Therefore, for the first time to our knowledge, we propose a system...

  4. Deriving input parameters for cost-effectiveness modeling: taxonomy of data types and approaches to their statistical synthesis.

    Science.gov (United States)

    Saramago, Pedro; Manca, Andrea; Sutton, Alex J

    2012-01-01

    The evidence base informing economic evaluation models is rarely derived from a single source. Researchers are typically expected to identify and combine available data to inform the estimation of model parameters for a particular decision problem. The absence of clear guidelines on what data can be used and how to effectively synthesize this evidence base under different scenarios inevitably leads to different approaches being used by different modelers. The aim of this article is to produce a taxonomy that can help modelers identify the most appropriate methods to use when synthesizing the available data for a given model parameter. This article developed a taxonomy based on possible scenarios faced by the analyst when dealing with the available evidence. While mainly focusing on clinical effectiveness parameters, this article also discusses strategies relevant to other key input parameters in any economic model (i.e., disease natural history, resource use/costs, and preferences). The taxonomy categorizes the evidence base for health economic modeling according to whether 1) single or multiple data sources are available, 2) individual or aggregate data are available (or both), or 3) individual or multiple decision model parameters are to be estimated from the data. References to examples of the key methodological developments for each entry in the taxonomy together with citations to where such methods have been used in practice are provided throughout. The use of the taxonomy developed in this article hopes to improve the quality of the synthesis of evidence informing decision models by bringing to the attention of health economics modelers recent methodological developments in this field. Copyright © 2012 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  5. A facile synthesis method of hydroxyethyl cellulose-silver nanoparticle scaffolds for skin tissue engineering applications.

    Science.gov (United States)

    Zulkifli, Farah Hanani; Hussain, Fathima Shahitha Jahir; Zeyohannes, Senait Sileshi; Rasad, Mohammad Syaiful Bahari Abdull; Yusuff, Mashitah M

    2017-10-01

    Green porous and ecofriendly scaffolds have been considered as one of the potent candidates for tissue engineering substitutes. The objective of this study is to investigate the biocompatibility of hydroxyethyl cellulose (HEC)/silver nanoparticles (AgNPs), prepared by the green synthesis method as a potential host material for skin tissue applications. The substrates which contained varied concentrations of AgNO 3 (0.4%-1.6%) were formed in the presence of HEC, were dissolved in a single step in water. The presence of AgNPs was confirmed visually by the change of color from colorless to dark brown, and was fabricated via freeze-drying technique. The outcomes exhibited significant porosity of >80%, moderate degradation rate, and tremendous value of water absorption up to 1163% in all samples. These scaffolds of HEC/AgNPs were further characterized by SEM, UV-Vis, ATR-FTIR, TGA, and DSC. All scaffolds possessed open interconnected pore size in the range of 50-150μm. The characteristic peaks of Ag in the UV-Vis spectra (417-421nm) revealed the formation of AgNPs in the blend composite. ATR-FTIR curve showed new existing peak, which implies the oxidation of HEC in the cellulose derivatives. The DSC thermogram showed augmentation in T g with increased AgNO 3 concentration. Preliminary studies of cytotoxicity were carried out in vitro by implementation of the hFB cells on the scaffolds. The results substantiated low toxicity of HEC/AgNPs scaffolds, thus exhibiting an ideal characteristic in skin tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Large Scale Screening of Southern African Plant Extracts for the Green Synthesis of Gold Nanoparticles Using Microtitre-Plate Method

    Directory of Open Access Journals (Sweden)

    Abdulrahman M. Elbagory

    2016-11-01

    Full Text Available The preparation of gold nanoparticles (AuNPs involves a variety of chemical and physical methods. These methods use toxic and environmentally harmful chemicals. Consequently, the synthesis of AuNPs using green chemistry has been under investigation to develop eco-friendly nanoparticles. One approach to achieve this is the use of plant-derived phytochemicals that are capable of reducing gold ions to produce AuNPs. The aim of this study was to implement a facile microtitre-plate method to screen a large number of aqueous plant extracts to determine the optimum concentration (OC for the bio-synthesis of the AuNPs. Several AuNPs of different sizes and shapes were successfully synthesized and characterized from 17 South African plants. The characterization was done using Ultra Violet-Visible Spectroscopy, Dynamic Light Scattering, High Resolution Transmission Electron Microscopy and Energy-Dispersive X-ray Spectroscopy. We also studied the effects of temperature on the synthesis of the AuNPs and showed that changes in temperatures affect the size and dispersity of the generated AuNPs. We also evaluated the stability of the synthesized AuNPs and showed that some of them are stable in biological buffer solutions.

  7. Pharmaceutical supply chain models: A synthesis from a systems view of operations research

    Directory of Open Access Journals (Sweden)

    Ettore Settanni

    Full Text Available This research evaluates reconfiguration opportunities in Pharmaceutical Supply Chains (PSC resulting from technology interventions in manufacturing, and new, more patient-centric delivery models. A critical synthesis of the academic and practice literature is used to identify, conceptualise, analyse and categorise PSC models. From a theoretical perspective, a systems view of operations research is adopted to provide insights on a broader range of OR activities, from conceptual to mathematical modelling and model solving, up to implementation.The research demonstrates that: 1 current definitions of the PSC are largely production-centric and fail to capture patient consumption, and hence healthcare outcomes; 2 most PSC mathematical models lack adequate conceptualisation of the structure and behaviour of the supply chain, and the boundary conditions that need to be considered for a given problem; 3 models do not adequately specify current unit operations or future production technology options, and are therefore unable to address the critical questions around alternative product or process technologies; 4 economic evaluations are limited to direct costing, rather than systemic approaches such as supply chain costing and total cost of ownership.While current models of the PSC may help with the optimisation of specific unit operations, their theoretical benefits could be offset by the dynamics of complex upstream (supply and downstream (distribution and healthcare delivery systems. To overcome these limitations, this research provides initial directions towards an integrated systems approach to PSC modelling. This perspective involves problem conceptualisation and boundary definition; design, formulation and solution of mathematical models, through to practical implementation of identified solutions. For both academics and practitioners, research findings suggest a systems approach to PSC modelling can provide improved conceptualisation and

  8. Numerical methods in Markov chain modeling

    Science.gov (United States)

    Philippe, Bernard; Saad, Youcef; Stewart, William J.

    1989-01-01

    Several methods for computing stationary probability distributions of Markov chains are described and compared. The main linear algebra problem consists of computing an eigenvector of a sparse, usually nonsymmetric, matrix associated with a known eigenvalue. It can also be cast as a problem of solving a homogeneous singular linear system. Several methods based on combinations of Krylov subspace techniques are presented. The performance of these methods on some realistic problems are compared.

  9. Sound Synthesis of the Harpsichord Using a Computationally Efficient Physical Model

    Science.gov (United States)

    Välimäki, Vesa; Penttinen, Henri; Knif, Jonte; Laurson, Mikael; Erkut, Cumhur

    2004-12-01

    A sound synthesis algorithm for the harpsichord has been developed by applying the principles of digital waveguide modeling. A modification to the loss filter of the string model is introduced that allows more flexible control of decay rates of partials than is possible with a one-pole digital filter, which is a usual choice for the loss filter. A version of the commuted waveguide synthesis approach is used, where each tone is generated with a parallel combination of the string model and a second-order resonator that are excited with a common excitation signal. The second-order resonator, previously proposed for this purpose, approximately simulates the beating effect appearing in many harpsichord tones. The characteristic key-release thump terminating harpsichord tones is reproduced by triggering a sample that has been extracted from a recording. A digital filter model for the soundboard has been designed based on recorded bridge impulse responses of the harpsichord. The output of the string models is injected in the soundboard filter that imitates the reverberant nature of the soundbox and, particularly, the ringing of the short parts of the strings behind the bridge.

  10. Sound Synthesis of the Harpsichord Using a Computationally Efficient Physical Model

    Directory of Open Access Journals (Sweden)

    Knif Jonte

    2004-01-01

    Full Text Available A sound synthesis algorithm for the harpsichord has been developed by applying the principles of digital waveguide modeling. A modification to the loss filter of the string model is introduced that allows more flexible control of decay rates of partials than is possible with a one-pole digital filter, which is a usual choice for the loss filter. A version of the commuted waveguide synthesis approach is used, where each tone is generated with a parallel combination of the string model and a second-order resonator that are excited with a common excitation signal. The second-order resonator, previously proposed for this purpose, approximately simulates the beating effect appearing in many harpsichord tones. The characteristic key-release thump terminating harpsichord tones is reproduced by triggering a sample that has been extracted from a recording. A digital filter model for the soundboard has been designed based on recorded bridge impulse responses of the harpsichord. The output of the string models is injected in the soundboard filter that imitates the reverberant nature of the soundbox and, particularly, the ringing of the short parts of the strings behind the bridge.

  11. Probing Evolutionary Population Synthesis Models in the Near Infrared with Early Type Galaxies

    Science.gov (United States)

    Dahmer-Hahn, Luis Gabriel; Riffel, Rogério; Rodríguez-Ardila, Alberto; Martins, Lucimara P.; Kehrig, Carolina; Heckman, Timothy M.; Pastoriza, Miriani G.; Dametto, Natacha Z.

    2018-02-01

    We performed a near-infrared (NIR, ˜1.0μm-2.4μm) stellar population study in a sample of early type galaxies. The synthesis was performed using five different evolutionary population synthesis libraries of models. Our main results can be summarized as follows: low spectral resolution libraries are not able to produce reliable results when applied to the NIR alone, with each library finding a different dominant population. The two newest higher resolution models, on the other hand, perform considerably better, finding consistent results to each other and to literature values. We also found that optical results are consistent with each other even for lower resolution models. We also compared optical and NIR results, and found out that lower resolution models tend to disagree in the optical and in the NIR, with higher fraction of young populations in the NIR and dust extinction ˜1 magnitude higher than optical values. For higher resolution models, optical and NIR results tend do aggree much better, suggesting that a higher spectral resolution is fundamental to improve the quality of the results.

  12. Dynamic spatial panels : models, methods, and inferences

    NARCIS (Netherlands)

    Elhorst, J. Paul

    This paper provides a survey of the existing literature on the specification and estimation of dynamic spatial panel data models, a collection of models for spatial panels extended to include one or more of the following variables and/or error terms: a dependent variable lagged in time, a dependent

  13. A Method for Model Checking Feature Interactions

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Le Guilly, Thibaut; Ravn, Anders Peter

    2015-01-01

    This paper presents a method to check for feature interactions in a system assembled from independently developed concurrent processes as found in many reactive systems. The method combines and refines existing definitions and adds a set of activities. The activities describe how to populate the ...

  14. Conversion of Carbon Dioxide to Ethanol by Electrochemical Synthesis Method Using Brass as A Cathode

    Directory of Open Access Journals (Sweden)

    Septian Ramadan

    2017-09-01

    Full Text Available The effect of potential and gas flow rate were investigated to determine the optimum conditions of the electrochemical synthesis process to convert carbon dioxide to ethanol. The conversion process is carried out using a NaHCO3 electrolyte solution in an electrochemical reactor equipped with a cathode and anode. As cathode is used brass, while as anode is used carbon. The result of the electrochemical synthesis process was analyzed by gas chromatography to determine the content of the compounds produced qualitatively and quantitatively. The optimum electrochemical synthesis conditions to convert carbon dioxide to ethanol are potential and gas flow rate are 3 volts and 0.5 L/minutes with ethanol concentration yielded 1.32%.

  15. Conversion of Carbon Dioxide into Ethanol by Electrochemical Synthesis Method Using Cu-Zn Electrode

    Science.gov (United States)

    Riyanto; Ramadan, S.; Fariduddin, S.; Aminudin, A. R.; Hayatri, A. K.

    2018-01-01

    Research on conversion of carbon dioxide into ethanol has been done. The conversion process is carried out in a sodium bicarbonate electrolyte solution in an electrochemical synthesis reactor. As cathode was used Cu-Zn, while as anode carbon was utilized. Variations of voltage, concentration of sodium bicarbonate electrolyte solution and time of electrolysis were performed to determine the optimum conditions to convert carbon dioxide into ethanol. Sample of the electrochemical synthesis process was analyzed by gas chromatography. From the result, it is found that the optimum conditions of the electrochemical synthesis process of carbon dioxide conversion into ethanol are voltage, concentration of sodium bicarbonate electrolyte solution and time of electrolysis are 3 volts, 0.4 M and 90 minutes with the ethanol concentration of 10.44%.

  16. Systematic methods for synthesis and design of sustainable chemical and biochemical processes

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    , biomass, coal, natural gas, rock, etc., that are usually extracted), to a bigger set of basic chemical products (such as, ethylene, benzene sulfuric acid, ammonia, etc., that are produced in large quantities), to an even bigger set of intermediates (such as, methanol, urea, succinic acid, ethylene glycol...... from the renewable resources, the sustainability of the product and therefore the process can be improved. Also, the number of alternatives that exist provide opportunities and challenges to find the best synthesis routes, for example, for process intensification or a multi-product processing complex...... like a biorefinery. The process synthesis design problem can be formulated as one where first a synthesis-design target (a process with desired qualities) is defined and then design alternatives (process flowsheets for different raw material-product connection) that match the target are identified...

  17. Continuous synthesis of drug-loaded nanoparticles using microchannel emulsification and numerical modeling: effect of passive mixing

    Directory of Open Access Journals (Sweden)

    Ortiz de Solorzano I

    2016-07-01

    Full Text Available Isabel Ortiz de Solorzano,1,2,* Laura Uson,1,2,* Ane Larrea,1,2,* Mario Miana,3 Victor Sebastian,1,2 Manuel Arruebo1,2 1Department of Chemical Engineering and Environmental Technologies, Institute of Nanoscience of Aragon (INA, University of Zaragoza, 2CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN, Centro de Investigación Biomédica en Red, Madrid, 3ITAINNOVA, Instituto Tecnológico de Aragón, Materials & Components, Zaragoza, Spain *These authors contributed equally to this work Abstract: By using interdigital microfluidic reactors, monodisperse poly(d,l lactic-co-glycolic acid nanoparticles (NPs can be produced in a continuous manner and at a large scale (~10 g/h. An optimized synthesis protocol was obtained by selecting the appropriated passive mixer and fluid flow conditions to produce monodisperse NPs. A reduced NP polydispersity was obtained when using the microfluidic platform compared with the one obtained with NPs produced in a conventional discontinuous batch reactor. Cyclosporin, an immunosuppressant drug, was used as a model to validate the efficiency of the microfluidic platform to produce drug-loaded monodisperse poly(d,l lactic-co-glycolic acid NPs. The influence of the mixer geometries and temperatures were analyzed, and the experimental results were corroborated by using computational fluid dynamic three-dimensional simulations. Flow patterns, mixing times, and mixing efficiencies were calculated, and the model supported with experimental results. The progress of mixing in the interdigital mixer was quantified by using the volume fractions of the organic and aqueous phases used during the emulsification–evaporation process. The developed model and methods were applied to determine the required time for achieving a complete mixing in each microreactor at different fluid flow conditions, temperatures, and mixing rates. Keywords: microchannel emulsification, high-throughput synthesis, drug-loaded polymer

  18. Chemical protein synthesis: Inventing synthetic methods to decipher how proteins work.

    Science.gov (United States)

    Kent, Stephen

    2017-09-15

    Total chemical synthesis of proteins has been rendered practical by the chemical ligation principle: chemoselective condensation of unprotected peptide segments equipped with unique, mutually reactive functional groups, enabled by formation of a non-native replacement for the peptide bond. Ligation chemistries are briefly described, including native chemical ligation - thioester-mediated, amide-forming reaction at Xaa-Cys sites - and its extensions. Case studies from the author's own works are used to illustrate the utility and applications of chemical protein synthesis. Selected recent developments in the field are briefly discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Power to Fuels: Dynamic Modeling of a Slurry Bubble Column Reactor in Lab-Scale for Fischer Tropsch Synthesis under Variable Load of Synthesis Gas

    Directory of Open Access Journals (Sweden)

    Siavash Seyednejadian

    2018-03-01

    Full Text Available This research developed a comprehensive computer model for a lab-scale Slurry Bubble Column Reactor (SBCR (0.1 m Dt and 2.5 m height for Fischer–Tropsch (FT synthesis under flexible operation of synthesis gas load flow rates. The variable loads of synthesis gas are set at 3.5, 5, 7.5 m3/h based on laboratory adjustments at three different operating temperatures (483, 493 and 503 K. A set of Partial Differential Equations (PDEs in the form of mass transfer and chemical reaction are successfully coupled to predict the behavior of all the FT components in two phases (gas and liquid over the reactor bed. In the gas phase, a single-bubble-class-diameter (SBCD is adopted and the reduction of superficial gas velocity through the reactor length is incorporated into the model by the overall mass balance. Anderson Schulz Flory distribution is employed for reaction kinetics. The modeling results are in good agreement with experimental data. The results of dynamic modeling show that the steady state condition is attained within 10 min from start-up. Furthermore, they show that step-wise syngas flow rate does not have a detrimental influence on FT product selectivity and the dynamic modeling of the slurry reactor responds quite well to the load change conditions.

  20. Combining static and dynamic modelling methods: a comparison of four methods

    NARCIS (Netherlands)

    Wieringa, Roelf J.

    1995-01-01

    A conceptual model of a system is an explicit description of the behaviour required of the system. Methods for conceptual modelling include entity-relationship (ER) modelling, data flow modelling, Jackson System Development (JSD) and several object-oriented analysis method. Given the current

  1. A Pattern-Oriented Approach to a Methodical Evaluation of Modeling Methods

    Directory of Open Access Journals (Sweden)

    Michael Amberg

    1996-11-01

    Full Text Available The paper describes a pattern-oriented approach to evaluate modeling methods and to compare various methods with each other from a methodical viewpoint. A specific set of principles (the patterns is defined by investigating the notations and the documentation of comparable modeling methods. Each principle helps to examine some parts of the methods from a specific point of view. All principles together lead to an overall picture of the method under examination. First the core ("method neutral" meaning of each principle is described. Then the methods are examined regarding the principle. Afterwards the method specific interpretations are compared with each other and with the core meaning of the principle. By this procedure, the strengths and weaknesses of modeling methods regarding methodical aspects are identified. The principles are described uniformly using a principle description template according to descriptions of object oriented design patterns. The approach is demonstrated by evaluating a business process modeling method.

  2. Fire Synthesis

    Indian Academy of Sciences (India)

    1000ºC or special infrastructure which require careful maintenance. In such a situation fire synthesis is a simpler method that can be adopted for the bulk production of high purity alumina and related oxides. Fire Synthesis. Preparation of Alumina ...

  3. Two-Polarisation Physical Model of Bowed Strings with Nonlinear Contact and Friction Forces, and Application to Gesture-Based Sound Synthesis

    Directory of Open Access Journals (Sweden)

    Charlotte Desvages

    2016-05-01

    Full Text Available Recent bowed string sound synthesis has relied on physical modelling techniques; the achievable realism and flexibility of gestural control are appealing, and the heavier computational cost becomes less significant as technology improves. A bowed string sound synthesis algorithm is designed, by simulating two-polarisation string motion, discretising the partial differential equations governing the string’s behaviour with the finite difference method. A globally energy balanced scheme is used, as a guarantee of numerical stability under highly nonlinear conditions. In one polarisation, a nonlinear contact model is used for the normal forces exerted by the dynamic bow hair, left hand fingers, and fingerboard. In the other polarisation, a force-velocity friction curve is used for the resulting tangential forces. The scheme update requires the solution of two nonlinear vector equations. The dynamic input parameters allow for simulating a wide range of gestures; some typical bow and left hand gestures are presented, along with synthetic sound and video demonstrations.

  4. Variation in the Mississippi River Plume from Data Synthesis of Model Outputs and MODIS Imagery

    Science.gov (United States)

    Fitzpatrick, C.; Kolker, A.; Chu, P. Y.

    2017-12-01

    Understanding the Mississippi River (MR) plume's interaction with the open ocean is crucial for understanding many processes in the Gulf of Mexico. Though the Mississippi River and its delta and plume have been studied extensively, recent archives of model products and satellite imagery have allowed us to highlight patterns in plume behavior over the last two decades through large scale data synthesis. Using 8 years of USGS discharge data and Landsat imagery, we identified the spatial extent, geographic patterns, depth, and freshwater concentration of the MR plume across seasons and years. Using 20 years of HYCOM (HYbrid Coordinate Ocean Model) analysis and reanalysis model output, and several years of NGOFS FVCOM model outputs, we mapped the minimum and maximum spatial area of the MR plume, and its varied extent east and west. From the synthesis and analysis of these data, the statistical probability of the MR plume's spatial area and geographical extent were computed. Measurements of the MR plume and its response to river discharge may predict future behavior and provide a path forward to understanding MR plume influence on nearby ecosystems.

  5. Highly efficient synthetic method onpyroacm resin using the boc SPPS protocol for C-terminal cysteine peptide synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Juvekar, Vinayak; Kim, Kang Tae; Gong, Young Dae [Innovative Drug Library Research Center, Dept. of Chemistry, College of Science, Dongguk University, Seoul (Korea, Republic of)

    2017-01-15

    A very effective process on Pyroacm resin was developed for solid-phase peptide synthesis (SPPS) of C-terminal cysteine and cysteine ester peptides. The process uses cysteine side chain anchoring to the Pyroacm resin and the Boc protocol for SPPS. The Pyroacm resin showed remarkable stability under standard trifluoromethanesulfonic acid (TFMSA) cleavage condition. TFMSA cleavage of protecting groups generates a peptide-linked resin, which can be subjected to peptide modification reactions. Finally, the peptide can be cleaved from the resin using methoxycarbonylsulfenyl chloride. The utility of this protocol was demonstrated by its applications to the synthesis of model peptides, key intermediates in the preparation of natural products riparin 1.2 and a-factor.

  6. Synthesis mechanism of an Al-Ti-C grain refiner master alloy prepared by a new method

    Science.gov (United States)

    Zhang, B. Q.; Lu, L.; Lai, M. O.; Fang, H. S.; Ma, H. T.; Li, J. G.

    2003-08-01

    The mechanisms of in-situ synthesis of an Al-Ti-C grain-refiner master alloy, prepared by adding a powder mixture of potassium titanium fluoride and carbon into an aluminum melt, have been systematically studied. It was found that vigorous reactions occurred at the initial stage of reaction and then slowed down. After about 20 minutes, the reactions, which led the formation of blocky titanium aluminides and submicron titanium carbides in the aluminum matrix, appeared to reach completion. Potassium titanium fluoride reacted with aluminum and carbon at 724 °C and 736 °C, respectively, resulting in the formation of titanium aluminides and titanium carbides in the aluminum matrix as well as in the formation of a low-melting-point slag of binary potassium aluminofluorides. The reaction between potassium titanium fluoride and carbon is believed to be the predominant mechanism in the synthesis of TiC by this method.

  7. An introduction to statistical parametric speech synthesis

    Indian Academy of Sciences (India)

    - like models, has become competitive with established concatenative techniques over the last few years. This paper offers a non-mathematical introduction to this method of speech synthesis. It is intended to be complementary to the wide ...

  8. O-acyl isopeptide method: development of an O-acyl isodipeptide unit for Boc SPPS and its application to the synthesis of Aβ1-42 isopeptide.

    Science.gov (United States)

    Yoshiya, Taku; Uemura, Tsuyoshi; Maruno, Takahiro; Kubo, Shigeru; Kiso, Yoshiaki; Sohma, Youhei; Kobayashi, Yuji; Yoshizawa-Kumagaye, Kumiko; Nishiuchi, Yuji

    2014-09-01

    The O-acyl isopeptide method was developed for the efficient preparation of difficult sequence-containing peptide. Furthermore, development of the O-acyl isodipeptide unit for Fmoc chemistry simplified its synthetic procedure by solid-phase peptide synthesis. Here, we report a novel isodipeptide unit for Boc chemistry, and the unit was successfully applied to the synthesis of amyloid β peptide. Combination of Boc chemistry and the isodipeptide unit would be an effective method for the synthesis of many difficult peptides. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  9. Synthesis and luminescent properties of Eu2+ doped BaZn2Si2O7 phosphors by combustion-assisted synthesis method

    International Nuclear Information System (INIS)

    Yao Shanshan; Xue Lihong; Yan Youwei

    2011-01-01

    Research highlights: → The orthorhombic BaZnSi 2 O 7 :Eu 2+ green emitting phosphor was prepared by the combustion-assisted synthesis method. → The critical quenching concentration of Eu 2+ in BaZnSi 2 O 7 :Eu 2+ phosphor is about 0.05. → The corresponding concentration quenching mechanism is verified to be a dipole-dipole interaction. → The CIE of the optimized sample was calculated (x, y) = (0.24, 0.58). - Abstract: A green emitting phosphor of the orthorhombic BaZn 2 Si 2 O 7 :Eu 2+ was prepared by the combustion-assisted synthesis method and an efficient green emission under near-ultraviolet was observed. The luminescence and crystallinity were investigated by using luminescence spectrometry, X-ray diffractometry (XRD). The emission spectrum shows a single intensive band centered at 522 nm, which corresponds to the 4f6 5 d 1 → 4f 7 transition of Eu 2+ . The excitation spectrum is a broad extending from 260 to 465 nm, which matches the mission of ultraviolet light-emitting diodes (UV-LEDs). The critical quenching concentration of Eu 2+ in BaZn 2 Si 2 O 7 :Eu 2+ phosphor is about 0.05. The corresponding concentration quenching mechanism is verified to be a dipole-dipole interaction. The chromaticity coordinates were obtained from the luminescence emission spectrum. The results indicate that BaZn 2 Si 2 O 7 :Eu 2+ can be potentially useful as a UV radiation-converting phosphor for white light-emitting diodes (LEDs).

  10. Methods for the synthesis of tritium-labelled fatty acids and their derivatives, oxylipins and steroids

    International Nuclear Information System (INIS)

    Shevchenko, Valerii P; Nagaev, Igor Yu; Myasoedov, Nikolai F

    1999-01-01

    The achievements in the field of synthesis and application of tritium-labelled oxylipins, steroids, fatty acids, phospho-, sphingo- and other lipids are reviewed. The importance of these studies for the solution of current problems of biochemistry, biology and pharmacology is exemplified in the application of labelled compounds. The bibliography includes 148 references.

  11. A convenient and efficient one-step method for the synthesis of ...

    African Journals Online (AJOL)

    hydroxy-5-methyl benzaldehyde with a mole of N,N'-bis(2-pyridyl)dopamine in THF at ambient conditions in high yield (75-80%). KEY WORDS: Dicompartmental ligand, Synthesis, Phenol-based ligand, Acyclic ligand. Bull. Chem. Soc. Ethiop. 2010 ...

  12. Synthesis of nanocrystalline TiO2 by tartarate gel method

    Indian Academy of Sciences (India)

    Unknown

    Keywords. Ceramics; oxides; chemical synthesis; X-ray diffraction; microscopy. 1. Introduction. Titanium dioxide (TiO2) is an important industrial material as a main component of paint, pigment, cosmetics and as a support for vanadium DeNOx catalyst (Fox and Dulay. 1993; Samuel et al 2004). It has also been used for opti-.

  13. Process synthesis, design and analysis using process-group contribution method

    DEFF Research Database (Denmark)

    Kumar Tula, Anjan; Eden, Mario Richard; Gani, Rafiqul

    2014-01-01

    This paper describes the development and application of a framework for synthesis, design, and analysis of chemical and biochemical processes. The framework is based on the principle of group contribution used for prediction of physical properties. The fundamental pillars of this methodology...

  14. Chemical synthesis of membrane proteins by the removable backbone modification method.

    Science.gov (United States)

    Tang, Shan; Zuo, Chao; Huang, Dong-Liang; Cai, Xiao-Ying; Zhang, Long-Hua; Tian, Chang-Lin; Zheng, Ji-Shen; Liu, Lei

    2017-12-01

    Chemical synthesis can produce membrane proteins bearing specifically designed modifications (e.g., phosphorylation, isotope labeling) that are difficult to obtain through recombinant protein expression approaches. The resulting homogeneously modified synthetic membrane proteins are valuable tools for many advanced biochemical and biophysical studies. This protocol describes the chemical synthesis of membrane proteins by condensation of transmembrane peptide segments through native chemical ligation. To avoid common problems encountered due to the poor solubility of transmembrane peptides in almost any solvent, we describe an effective procedure for the chemical synthesis of membrane proteins through the removable-backbone modification (RBM) strategy. Two key steps of this protocol are: (i) installation of solubilizing Arg4-tagged RBM groups into the transmembrane peptides at any primary amino acid through Fmoc (9-fluorenylmethyloxycarbonyl) solid-phase peptide synthesis and (ii) native ligation of the full-length sequence, followed by removal of the RBM tags by TFA (trifluoroacetic acid) cocktails to afford the native protein. The installation of RBM groups is achieved by using 4-methoxy-5-nitrosalicyladehyde by reduction amination to incorporate an activated O-to-N acyl transfer auxiliary. The Arg4-tag-modified membrane-spanning peptide segments behave like water-soluble peptides to facilitate their purification, ligation and mass characterization.

  15. Methods for Collecting Postschool Outcomes Data on Young Adults with Disabilities: A Literature Synthesis

    Science.gov (United States)

    Alverson, Charlotte Y.; Naranjo, Jason M.; Yamamoto, Scott; Unruh, Deanne K.

    2010-01-01

    The current U.S. federal mandate for educational accountability requires state departments of education to collect data on the postschool employment and postsecondary school and/or training enrollment of young adults with disabilities. To examine how these data have been collected, we conducted a literature synthesis of follow-up and follow-along…

  16. Synthesis of lithium silicates generators of tritium by a modified method of combustion

    International Nuclear Information System (INIS)

    Cruz G, D.

    2003-01-01

    The ceramics of lithium have been proposed as generating materials of tritium through the following reaction: 6 Li + 1 n → 4 He + 3 H . In previous works carried out by Pfeiffer and collaborators, the lithium silicates generators of tritium were prepared using the following methods: reactions of solid state, precipitation and sol-gel synthesis. Although those methods have advantages, it is required of heating at high temperatures (900 C during four hours) to be able to obtain the crystalline compounds. Those products found in these works were diverse crystallization forms of the lithium silicates and of SiO 2 , such as, Li 2 SiO 3 , Li 2 Si 2 0 5 , Li 4 SiO 4 , and quartz (SiO 2 ). The combustion method uses exothermic reactions to take place ceramic compounds. The precursor solutions are mixtures of the nitrate of metal oxidizer and the fuels (urea, glycine, carbohydrazide). However the reported method in the literature, it is not useful to prepare lithium silicates, for what was modified using non oxidizers compounds. The lithium hydroxide (LiOH) and the silicic acid (H 2 SiO 3 ) they were the compounds non oxidizers used, and the urea (CH 4 N 2 O) it was the one fuel. They were carried out two series of experiments; inside the series 1 of experiments are varied the molar ratio of lithium hydroxide and urea (LiOH : H 2 SiO 3 = 1, 2 and 3, LiOH : CH 4 N 2 O = 1, 2, 3, 4 and 5) and the prepared mixtures were taken to one muffle previously preheated to a temperature of 450 C during 5 minutes. In the series 2 of experiments was studied the effect of the temperature and of the washed with distilled water in the prepared samples with the following molar ratios: LiOH : H 2 SiO 3 : CH 4 N 2 O = 1:1:3, 2:1:3, 3:1:3 and 3:1:6, those which were heated to temperatures from 450 C up to 750 C and were washed. The obtained samples were characterized by X-ray diffraction (XRD), Infrared spectroscopy (I S), semiquantitative elemental analysis (EDS) and Thermal gravimetric

  17. Resampling methods for evaluating classification accuracy of wildlife habitat models

    Science.gov (United States)

    Verbyla, David L.; Litvaitis, John A.

    1989-11-01

    Predictive models of wildlife-habitat relationships often have been developed without being tested The apparent classification accuracy of such models can be optimistically biased and misleading. Data resampling methods exist that yield a more realistic estimate of model classification accuracy These methods are simple and require no new sample data. We illustrate these methods (cross-validation, jackknife resampling, and bootstrap resampling) with computer simulation to demonstrate the increase in precision of the estimate. The bootstrap method is then applied to field data as a technique for model comparison We recommend that biologists use some resampling procedure to evaluate wildlife habitat models prior to field evaluation.

  18. Interfacial Bioorthogonal Chemistry for Biomaterials Synthesis and Patterning and Development of Catalytic Method for "Turning-On" the Tetrazine Ligation

    Science.gov (United States)

    Zhang, Han

    The bioorthogonal trans-cyclooctene-tetrazine ligation has emerged into a powerful tool in the field of biomedical research. The development and the versatile applications of tetrazine ligation was made possible by the advancement of trans-cyclooctene synthesis. Based on the previous art of photoisomerization methods in Fox group, I carried out the first practical photosynthesis of trans-cycloheptene derivatives that were stabilized as silver(I) complexes form, as well as the photoisomerization of silicon-containing hetero- trans-cycloheptene derivatives. The reactivity of both the trans-cycloheptene silver(I) complexes and the hetero-trans-cycloheptene derivatives were investigated. Based on the rapid trans-cyclooctene-tetrazine ligation, first example of interfacial crosslinking will be described in Chapter 2. Bioocompatible hyaluronic acid-based hydrogel microspheres and channels were generated in a diffusion controlled fashion. These hydrogels can be covalently tagged with 3D resolution without the help of any external stimulus or triggers. An in vitro tumor model was achieved by 3D encapsulation and culture of LNCaP prostate cancer cells. Also included in Chapter 2 will be a novel interfacial polymerization strategy developed for the synthesis of hybrid multiblock copolymer. Meter-long copolymer fibers were pulled out of interface of two immiscible solutions. The unique modular approach enables the facile incorporation of functional peptides into the copolymer to fine-tune its biological properties. A fibronectin-derived peptide was successfully introduced onto the fibers during the polymerization and dramatically promoted the attachment and alignment of fibroblasts and myoepithelial-like cells. In Chapter 3, a novel method to activate rapid bioorthogonal reactivity catalytically will be described. This was achieved by catalytic conversion of an unreactive, latent dihydrotetrazine to reaction-ready tetrazine functionality. Series of long wavelength

  19. The role anions on the synthesis of AlOOH nanoparticles using simple solvothermal method

    Directory of Open Access Journals (Sweden)

    Mozaffar Abdollahifar

    2018-03-01

    Full Text Available Effect of aluminium salts on the synthesis of AlOOH nanostructures has been successfully investigated in detail using solvothermal method, when ethanol and NaOH are solvent and pH adjusting agent, respectively. Fourier transform infrared spectroscopy (FTIR, X-ray powder diffraction (XRD, and field emission scanning electron microscopy (FESEM, were used to characterize the synthesized samples. The specific surface area, pore size distribution and pore structure of the different AlOOH structures were also discussed by the N2 adsorption/desorption test. According to our experimental results, the structure characterization revealed that for synthesized AlOOH nanostructures no obvious XRD peaks arising from other phases of alumina are found indicating pure AlOOH phase of products. Furthermore, the nitrogen adsorption and desorption measurements indicated that the obtained AlOOH nanoparticles from aluminium chloride at basic condition possess a high BET surface area of approximately 90 m2/g. Resumen: El efecto de las sales de aluminio sobre la síntesis de las nanoestructuras de AlOOH ha sido analizado en detalle satisfactoriamente usando el método solvotérmico, cuando el etanol y el NaOH son el disolvente y el agente de regulación del pH, respectivamente. Para clasificar las muestras sintetizadas se utilizaron la espectroscopia infrarroja por transformada de Fourier (FTIR, difracción de rayos X por polvo (XRD y microscopia electrónica de barrido de emisión de campo (FESEM. El área superficial específica, la distribución del tamaño del poro y la estructura de poros de las diferentes estructuras de AlOOH también se debatieron mediante la prueba de adsorción/desorción de N2. De acuerdo con nuestros resultados experimentales, la clasificación de la estructura reveló que en las nanoestructuras de AlOOH sintetizadas no se observan picos XRD evidentes derivados de otras fases de la alúmina que indican la fase pura de AlOOH de los productos

  20. A catalog of automated analysis methods for enterprise models.

    Science.gov (United States)

    Florez, Hector; Sánchez, Mario; Villalobos, Jorge

    2016-01-01

    Enterprise models are created for documenting and communicating the structure and state of Business and Information Technologies elements of an enterprise. After models are completed, they are mainly used to support analysis. Model analysis is an activity typically based on human skills and due to the size and complexity of the models, this process can be complicated and omissions or miscalculations are very likely. This situation has fostered the research of automated analysis methods, for supporting analysts in enterprise analysis processes. By reviewing the literature, we found several analysis methods; nevertheless, they are based on specific situations and different metamodels; then, some analysis methods might not be applicable to all enterprise models. This paper presents the work of compilation (literature review), classification, structuring, and characterization of automated analysis methods for enterprise models, expressing them in a standardized modeling language. In addition, we have implemented the analysis methods in our modeling tool.