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Sample records for based stabilization process

  1. Stability-based sorting: The forgotten process behind (not only) biological evolution.

    Science.gov (United States)

    Toman, Jan; Flegr, Jaroslav

    2017-12-21

    Natural selection is considered to be the main process that drives biological evolution. It requires selected entities to originate dependent upon one another by the means of reproduction or copying, and for the progeny to inherit the qualities of their ancestors. However, natural selection is a manifestation of a more general persistence principle, whose temporal consequences we propose to name "stability-based sorting" (SBS). Sorting based on static stability, i.e., SBS in its strict sense and usual conception, favours characters that increase the persistence of their holders and act on all material and immaterial entities. Sorted entities could originate independently from each other, are not required to propagate and need not exhibit heredity. Natural selection is a specific form of SBS-sorting based on dynamic stability. It requires some form of heredity and is based on competition for the largest difference between the speed of generating its own copies and their expiration. SBS in its strict sense and selection thus have markedly different evolutionary consequences that are stressed in this paper. In contrast to selection, which is opportunistic, SBS is able to accumulate even momentarily detrimental characters that are advantageous for the long-term persistence of sorted entities. However, it lacks the amplification effect based on the preferential propagation of holders of advantageous characters. Thus, it works slower than selection and normally is unable to create complex adaptations. From a long-term perspective, SBS is a decisive force in evolution-especially macroevolution. SBS offers a new explanation for numerous evolutionary phenomena, including broad distribution and persistence of sexuality, altruistic behaviour, horizontal gene transfer, patterns of evolutionary stasis, planetary homeostasis, increasing ecosystem resistance to disturbances, and the universal decline of disparity in the evolution of metazoan lineages. SBS acts on all levels in

  2. Stabilization of red fruit-based smoothies by high-pressure processing. Part A. Effects on microbial growth, enzyme activity, antioxidant capacity and physical stability.

    Science.gov (United States)

    Hurtado, Adriana; Guàrdia, Maria Dolors; Picouet, Pierre; Jofré, Anna; Ros, José María; Bañón, Sancho

    2017-02-01

    Non-thermal pasteurization by high-pressure processing (HPP) is increasingly replacing thermal processing (TP) to maintain the properties of fresh fruit products. However, most of the research on HPP-fruit products only partially addresses fruit-pressure interaction, which limits its practical interest. The objective of this study was to assess the use of a mild HPP treatment to stabilize red fruit-based smoothies (microbial, enzymatic, oxidative and physical stability). HPP (350 MPa/10 °C/5 min) was slightly less effective than TP (85 °C/7 min) in inactivating microbes (mesophilic and psychrophilic bacteria, coliforms, yeasts and moulds) in smoothies kept at 4 °C for up to 28 days. The main limitation of using HPP was its low efficacy in inactivating oxidative (polyphenol oxidase and peroxidase) and hydrolytic (pectin methyl esterase) enzymes. Data on antioxidant status, colour parameters, browning index, transmittance, turbidity and viscosity confirmed that the HPP-smoothies have a greater tendency towards oxidation and clarification, which might lead to undesirable sensory and nutritional changes (see Part B). The microbial quality of smoothies was adequately controlled by mild HPP treatment without affecting their physical-chemical characteristics; however, oxidative and hydrolytic enzymes are highly pressure-resistant, which suggests that additional strategies should be used to stabilize smoothies. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  3. Numerical modelling of levee stability based on coupled mechanical, thermal and hydrogeological processes

    Directory of Open Access Journals (Sweden)

    Dwornik Maciej

    2016-01-01

    Full Text Available The numerical modelling of coupled mechanical, thermal and hydrogeological processes for a soil levee is presented in the paper. The modelling was performed for a real levee that was built in Poland as a part of the ISMOP project. Only four parameters were changed to build different flood waves: the water level, period of water increase, period of water decrease, and period of low water level after the experiment. Results of numerical modelling shows that it is possible and advisable to calculate simultaneously changes of thermal and hydro-mechanical fields. The presented results show that it is also possible to use thermal sensors in place of more expensive pore pressure sensors, with some limitations. The results of stability analysis show that the levee is less stable when the water level decreases, after which factor of safety decreases significantly. For all flooding wave parameters described in the paper, the levee is very stable and factor of safety variations for any particular stage were not very large.

  4. Implementation of an ex situ stabilization technique at the Sand Springs superfund site to solidify and stabilize acid tar sludges involving a quick-lime based stabilization process and innovative equipment design

    International Nuclear Information System (INIS)

    McManus, R.W.; Grajczak, P.; Wilcoxson, J.C.; Webster, S.D.

    1997-01-01

    An old refinery site was safely remediated a year before schedule and for 25% less than final engineering estimates for the stabilization remedy thanks to energetic project management and innovative design involving ex situ stabilization/solidification of acid tar sludges. A quicklime based process, Dispersion by Chemical Reaction (DCR trademark), was employed to solidify and stabilize (SS) over 103,000 cubic meters (135,000 cubic yards) of petroleum waste, mostly acidic tarry sludge. The SS process was selected over competing methods because it afforded minimal volume increase, could readily achieve Record of Decision (ROD) specified physical and chemical treatment goals, could be implemented with treatment equipment that minimized emissions, and could be performed with low reagent usage and at low cost. To ensure treatment goals were achieved and an accelerated schedule met, a custom designed and fabricated transportable treatment unit (TTU) was employed to implement the process. The treated material was visually soil-like in character, it was left in stockpiles for periods of time, and it was placed and compacted in the on site landfill using standard earth-moving equipment

  5. Nonlinear relative-proportion-based route adjustment process for day-to-day traffic dynamics: modeling, equilibrium and stability analysis

    Science.gov (United States)

    Zhu, Wenlong; Ma, Shoufeng; Tian, Junfang; Li, Geng

    2016-11-01

    Travelers' route adjustment behaviors in a congested road traffic network are acknowledged as a dynamic game process between them. Existing Proportional-Switch Adjustment Process (PSAP) models have been extensively investigated to characterize travelers' route choice behaviors; PSAP has concise structure and intuitive behavior rule. Unfortunately most of which have some limitations, i.e., the flow over adjustment problem for the discrete PSAP model, the absolute cost differences route adjustment problem, etc. This paper proposes a relative-Proportion-based Route Adjustment Process (rePRAP) maintains the advantages of PSAP and overcomes these limitations. The rePRAP describes the situation that travelers on higher cost route switch to those with lower cost at the rate that is unilaterally depended on the relative cost differences between higher cost route and its alternatives. It is verified to be consistent with the principle of the rational behavior adjustment process. The equivalence among user equilibrium, stationary path flow pattern and stationary link flow pattern is established, which can be applied to judge whether a given network traffic flow has reached UE or not by detecting the stationary or non-stationary state of link flow pattern. The stability theorem is proved by the Lyapunov function approach. A simple example is tested to demonstrate the effectiveness of the rePRAP model.

  6. Carbon-Based CsPbBr3 Perovskite Solar Cells: All-Ambient Processes and High Thermal Stability.

    Science.gov (United States)

    Chang, Xiaowen; Li, Weiping; Zhu, Liqun; Liu, Huicong; Geng, Huifang; Xiang, Sisi; Liu, Jiaming; Chen, Haining

    2016-12-14

    The device instability has been an important issue for hybrid organic-inorganic halide perovskite solar cells (PSCs). This work intends to address this issue by exploiting inorganic perovskite (CsPbBr 3 ) as light absorber, accompanied by replacing organic hole transport materials (HTM) and the metal electrode with a carbon electrode. All the fabrication processes (including those for CsPbBr 3 and the carbon electrode) in the PSCs are conducted in ambient atmosphere. Through a systematical optimization on the fabrication processes of CsPbBr 3 film, carbon-based PSCs (C-PSCs) obtained the highest power conversion efficiency (PCE) of about 5.0%, a relatively high value for inorganic perovskite-based PSCs. More importantly, after storage for 250 h at 80 °C, only 11.7% loss in PCE is observed for CsPbBr 3 C-PSCs, significantly lower than that for popular CH 3 NH 3 PbI 3 C-PSCs (59.0%) and other reported PSCs, which indicated a promising thermal stability of CsPbBr 3 C-PSCs.

  7. Enhanced electrical stability of nitrate ligand-based hexaaqua complexes solution-processed ultrathin a-IGZO transistors

    Science.gov (United States)

    Choi, C.; Baek, Y.; Lee, B. M.; Kim, K. H.; Rim, Y. S.

    2017-12-01

    We report solution-processed, amorphous indium–gallium–zinc-oxide-based (a-IGZO-based) thin-film transistors (TFTs). Our proposed solution-processed a-IGZO films, using a simple spin-coating method, were formed through nitrate ligand-based metal complexes, and they were annealed at low temperature (250 °C) to achieve high-quality oxide films and devices. We investigated solution-processed a-IGZO TFTs with various thicknesses, ranging from 4 to 16 nm. The 4 nm-thick TFT films had smooth morphology and high-density, and they exhibited excellent performance, i.e. a high saturation mobility of 7.73  ±  0.44 cm2 V‑1 s‑1, a sub-threshold swing of 0.27 V dec‑1, an on/off ratio of ~108, and a low threshold voltage of 3.10  ±  0.30 V. However, the performance of the TFTs degraded as the film thickness was increased. We further performed positive and negative bias stress tests to examine their electrical stability, and it was noted that the operating behavior of the devices was highly stable. Despite a small number of free charges, the high performance of the ultrathin a-IGZO TFTs was attributed to the small effect of the thickness of the channel, low bulk resistance, the quality of the a-IGZO/SiO2 interface, and high film density.

  8. A study of the alterability of terminal residues stabilized by a mineral-binder-based solidification/stabilization process; Etude de l`alterabilite de residus ultimes stabilises par un procede de solidification, stabilisation a base de liants mineraux

    Energy Technology Data Exchange (ETDEWEB)

    Humez, N.; Prost, R. [Institut National de Recherches Agronomiques (INRA), 78 - Versailles (France). Unite de Science du Sol; Piketty, L.; Schnuriger, B.; Benchara, A.; Pichat, P. [Centre de Solidification, Stabilisation et Stockage, Sarp Industries, 78 - Limay (France)

    1997-12-31

    A new laboratory approach has been developed for the study of the long term behaviour of stabilized terminal residues, and is based on the experimental method for the study of rock alteration. The method consists in examining the migration of elements that are present in the solution contained in the pores, and studying the structural modifications which result from the dissolution of certain constituents, the transformation and the neo-formation of other ones in the material. The method allows for the evaluation, in a short time, of the alterability and perenniality of stabilized terminal wastes. Results show that the long term alterability of solidified/stabilized samples that have been processed using the ECOFIX method, is low

  9. Comparison of the fixation effects of heavy metals by cement rotary kiln co-processing and cement based solidification/stabilization.

    Science.gov (United States)

    Zhang, Junli; Liu, Jianguo; Li, Cheng; Jin, Yiying; Nie, Yongfeng; Li, Jinhui

    2009-06-15

    Cement rotary kiln co-processing of hazardous wastes and cement based solidification/stabilization could both immobilize heavy metals. The different retention mechanisms of the two technologies lead to different fixation effects of heavy metals. The same amount of heavy metal compounds were treated by the two types of fixation technologies. Long-term leaching test (160 days), the maximum availability leaching test (NEN 7341) and a modified three-step sequential extraction procedure, proposed by the Commission of the European Communities Bureau of Reference (BCR) were employed to compare the fixation effects of the two fixation technologies. The leaching concentrations in NEN 7341 and long-term leaching tests were compared with identification standard for hazardous wastes (GB5085.3-1996) and drinking water standard (GB5749-2005). The results indicate that the leaching concentrations of the long-term leaching test and NEN 7341 test were lower than the regulatory limits and the leached ratios were small. Both cement based solidification/stabilization and cement rotary kiln co-processing could effectively fix heavy metals. Calcination in a cement rotary kiln and the following hydration that follows during cement application could fix As, Cd, Pb and Zn more effectively and decrease the release to the environment. Cement solidification/stabilization technology has better effect in immobilizing Cr and Ni. Cr wastes are more fitful to be treated by cement solidification/stabilization.

  10. Metals and Alloys Material Stabilization Process Plan

    Energy Technology Data Exchange (ETDEWEB)

    RISENMAY, H.R.; BURK, R.A.

    2000-05-18

    This Plan outlines the process for brushing metal and alloys in accordance with the path forward discussed in the Integrated Project Management Plan for the Plutonium Finishing Plant Stabilization and Deactivation Project, HNF-3617, and requirements set forth in the Project Management Plan for Materials Stabilization, HNF-3605. This plan provides the basis for selection of the location to process, the processes involved, equipment to be used, and the characterization of the contents of the can. The scope of the process is from retrieval of metals and alloys from storage to transfer back to storage in a repackaged configuration.

  11. Metals and Alloys Material Stabilization Process Plan

    International Nuclear Information System (INIS)

    RISENMAY, H.R.; BURK, R.A.

    2000-01-01

    This Plan outlines the process for brushing metal and alloys in accordance with the path forward discussed in the Integrated Project Management Plan for the Plutonium Finishing Plant Stabilization and Deactivation Project, HNF-3617, and requirements set forth in the Project Management Plan for Materials Stabilization, HNF-3605. This plan provides the basis for selection of the location to process, the processes involved, equipment to be used, and the characterization of the contents of the can. The scope of the process is from retrieval of metals and alloys from storage to transfer back to storage in a repackaged configuration

  12. Adaptive GSA-based optimal tuning of PI controlled servo systems with reduced process parametric sensitivity, robust stability and controller robustness.

    Science.gov (United States)

    Precup, Radu-Emil; David, Radu-Codrut; Petriu, Emil M; Radac, Mircea-Bogdan; Preitl, Stefan

    2014-11-01

    This paper suggests a new generation of optimal PI controllers for a class of servo systems characterized by saturation and dead zone static nonlinearities and second-order models with an integral component. The objective functions are expressed as the integral of time multiplied by absolute error plus the weighted sum of the integrals of output sensitivity functions of the state sensitivity models with respect to two process parametric variations. The PI controller tuning conditions applied to a simplified linear process model involve a single design parameter specific to the extended symmetrical optimum (ESO) method which offers the desired tradeoff to several control system performance indices. An original back-calculation and tracking anti-windup scheme is proposed in order to prevent the integrator wind-up and to compensate for the dead zone nonlinearity of the process. The minimization of the objective functions is carried out in the framework of optimization problems with inequality constraints which guarantee the robust stability with respect to the process parametric variations and the controller robustness. An adaptive gravitational search algorithm (GSA) solves the optimization problems focused on the optimal tuning of the design parameter specific to the ESO method and of the anti-windup tracking gain. A tuning method for PI controllers is proposed as an efficient approach to the design of resilient control systems. The tuning method and the PI controllers are experimentally validated by the adaptive GSA-based tuning of PI controllers for the angular position control of a laboratory servo system.

  13. Enhancing probiotic stability in industrial processes

    Directory of Open Access Journals (Sweden)

    Miguel Gueimonde

    2012-06-01

    Full Text Available Background: Manufacture of probiotic products involves industrial processes that reduce the viability of the strains. This lost of viability constitutes an economic burden for manufacturers, compromising the efficacy of the product and preventing the inclusion of probiotics in many product categories. Different strategies have been used to improve probiotic stability during industrial processes. These include technological approaches, such as the modification of production parameters or the reformulation of products, as well as microbiological approaches focused on the strain intrinsic resistance. Among the later, both selection of natural strains with the desired properties and stress-adaptation of strains have been widely used. Conclusion: During recent years, the knowledge acquired on the molecular basis of stress-tolerance of probiotics has increased our understanding on their responses to industrial stresses. This knowledge on stress-response may nowadays be used for the selection of the best strains and industrial conditions in terms of probiotic stability in the final product.

  14. Effect of stabilization temperature during pyrolysis process of P84 co-polyimide-based tubular carbon membrane for H2/N2 and He/N2 separations

    Science.gov (United States)

    Sazali, N.; Salleh, W. N. W.; Ismail, A. F.; Ismail, N. H.; Aziz, F.; Yusof, N.; Hasbullah, H.

    2018-04-01

    In this study, the effect of stabilization temperature on the performance of tubular carbon membrane was being investigated. P84 co-polyimide-based tubular carbon membrane will be fabricated through the dip-coating technique. The tubular carbon membrane performance can be controlled by manipulating the pyrolysis conditions which was conducted at different stabilization temperatures of 250, 300, 350, 400, and 450°C under N2 environment (200 ml/min). The prepared membranes were characterized by using scanning electron microscopy (SEM), x-ray diffraction (XRD), and pure gas permeation system. The pure gas of H2, He, and N2 were used to determine the permeation properties of the carbon membrane. The P84 co-polyimide-based tubular carbon membrane stabilized at 300°C demonstrated an excellent permeation property with H2, He, and N2 gas permeance of 1134.51±2.87, 1287.22±2.86 and 2.98±1.28GPU, respectively. The highest H2/N2 and He/N2 selectivity of 380.71±2.34 and 431.95±2.61 was obtained when the stabilization temperature of 450°C was applied. It is concluded that the stabilization temperatures have protrusive effect on the carbon membrane properties specifically their pore structure, and eventually their gas separation properties.

  15. Stability of nonlinear repetitive processes with possible failures

    Directory of Open Access Journals (Sweden)

    J. P. Emelianova

    2014-01-01

    Full Text Available Nonlinear discrete-time repetitive processes with Markovian jumps are considered. For such processes stability analysis is developed and this result is then applied to iterative learning control design.Stability of nonlinear repetitive processes has not been developed previously in the current literature. This paper proposes and characterizes a stability theory for nonlinear repetitive processes that includes stability along the pass of linear examples as a special case.For considered systems the second Lyapunov method cannot be used. Because repetitive processes belong to a class of 2D systems in which state variables are depend on two independent variables and cannot be solved using all first differences of state variables. It is not allow us to find a first difference of Lyapunov function along the trajectory of the system without finding solution of a system of equations that fully excludes a main advantage of second Lyapunov method. At the same time the use of vector Lyapunov functions and discrete-time counterpart of the divergence operator of this function along the trajectories of system instead of first difference allow us to obtain constructive results.In this paper based on vector Lyapunov function approach sufficient conditions for pass profile exponential stability are obtained which in the linear case are obtained in terms of linear matrix inequalities and in the linear case without failures these conditions are reduced to known conditions of stability along the passA major application area where repetitive process stability theory can be used is Iterative Learning Control (ILC. The idea of ILC is following.If the system repeats the same finite duration operation over and over again, it is reasonable to use the input and output variables on the current pass for improving accuracy of performance of operations on the next pass.The new theoretical stability results are applied to ILC design under possible information failures. The ILC

  16. Estimating Vehicle Stability Region Based on Energy Function

    Directory of Open Access Journals (Sweden)

    Yu-guang Yan

    2015-01-01

    Full Text Available In order to improve the deficiency of vehicle stability region, according to vehicle nonlinear dynamic model, method of estimating vehicle spatial stability region was proposed. With Pacejka magic formula tire model, nonlinear 3DOF vehicle model was deduced and verified though vehicle test. Detailed detecting system and data processing were introduced. In addition, stability of the vehicle system was discussed using Hurwitz criterion. By establishing energy function for vehicle system, the vehicle’s stability region in 20 m/s was estimated based on Lyapunov theorem and vehicle system characteristics. Vehicle test in the same condition shows that the calculated stability region defined by Lyapunov and system stability theorem has good effect on characterized vehicle stability and it could be a valuable reference for vehicle stability evaluation.

  17. Efficiency and Stability in a Process of Teams Formation

    OpenAIRE

    Boncinelli, Leonardo; Pin, Paolo

    2014-01-01

    We analyze a team formation process that generalizes matching models and network formation models, allowing for overlapping teams of heterogeneous size. We apply different notions of stability: myopic team-wise stability, which extends to our setup the concept of pair-wise stability, coalitional stability, where agents are perfectly rational and able to coordinate, and stochastic stability, where agents are myopic and errors occur with vanishing probability. We find that, in many cases, coali...

  18. Phase Stability Diagrams for High Temperature Corrosion Processes

    Directory of Open Access Journals (Sweden)

    J. J. Ramos-Hernandez

    2013-01-01

    Full Text Available Corrosion phenomena of metals by fused salts depend on chemical composition of the melt and environmental conditions of the system. Detail knowledge of chemistry and thermodynamic of aggressive species formed during the corrosion process is essential for a better understanding of materials degradation exposed to high temperature. When there is a lack of kinetic data for the corrosion processes, an alternative to understand the thermodynamic behavior of chemical species is to utilize phase stability diagrams. Nowadays, there are several specialized software programs to calculate phase stability diagrams. These programs are based on thermodynamics of chemical reactions. Using a thermodynamic data base allows the calculation of different types of phase diagrams. However, sometimes it is difficult to have access to such data bases. In this work, an alternative way to calculate phase stability diagrams is presented. The work is exemplified in the Na-V-S-O and Al-Na-V-S-O systems. This system was chosen because vanadium salts is one of the more aggressive system for all engineering alloys, especially in those processes where fossil fuels are used.

  19. Signal Processing Methods for Liquid Rocket Engine Combustion Stability Assessments

    Science.gov (United States)

    Kenny, R. Jeremy; Lee, Erik; Hulka, James R.; Casiano, Matthew

    2011-01-01

    The J2X Gas Generator engine design specifications include dynamic, spontaneous, and broadband combustion stability requirements. These requirements are verified empirically based high frequency chamber pressure measurements and analyses. Dynamic stability is determined with the dynamic pressure response due to an artificial perturbation of the combustion chamber pressure (bomb testing), and spontaneous and broadband stability are determined from the dynamic pressure responses during steady operation starting at specified power levels. J2X Workhorse Gas Generator testing included bomb tests with multiple hardware configurations and operating conditions, including a configuration used explicitly for engine verification test series. This work covers signal processing techniques developed at Marshall Space Flight Center (MSFC) to help assess engine design stability requirements. Dynamic stability assessments were performed following both the CPIA 655 guidelines and a MSFC in-house developed statistical-based approach. The statistical approach was developed to better verify when the dynamic pressure amplitudes corresponding to a particular frequency returned back to pre-bomb characteristics. This was accomplished by first determining the statistical characteristics of the pre-bomb dynamic levels. The pre-bomb statistical characterization provided 95% coverage bounds; these bounds were used as a quantitative measure to determine when the post-bomb signal returned to pre-bomb conditions. The time for post-bomb levels to acceptably return to pre-bomb levels was compared to the dominant frequency-dependent time recommended by CPIA 655. Results for multiple test configurations, including stable and unstable configurations, were reviewed. Spontaneous stability was assessed using two processes: 1) characterization of the ratio of the peak response amplitudes to the excited chamber acoustic mode amplitudes and 2) characterization of the variability of the peak response

  20. Estimation of multiply digital process control system extractive distillation stability

    Directory of Open Access Journals (Sweden)

    V. S. Kudryashov

    2016-01-01

    Full Text Available An approach to stability analysis of digital control systems associated non-stationary object on the example of the rectification process. Object modeling with cross-connections and the control scheme of the described system, discrete transfer functions in the shift operators. The equations of connection for each output of the closed-loop system. To solve this problem developed an algorithm for estimating the margin of stability of multivariable digital control systems based on the discrete root criterion, comprising the following main stages: obtaining of the characteristic polynomial of the closed-loop system for each output; computation of eigenvalues of the system matrix in the state space to determine roots of the characteristic equation and the stability of the system; determination of the stability and margin of stability by the deviation of maximum module of the root from the boundary of the high variability. To obtain the characteristic polynomial of a as discrete models of controllers and channels of IP object-use the transfer function of the first order with transport delay. The simulation was performed at different parameters of the control object, which is characterized by a stable and an unstable state of the system. VA-den analysis of the numerical values of the roots and character of their location on the complex plane, which to you-water that the system is stable or unstable. To confirm the obtained results were calculated and presented dynamic characteristics of the closed-loop system under different conditions, which confirm the initial assessment, the root criterion. To determine the factor stability of multivariable digital systems is proposed to use the deviation of the maximum root of the characteristic equation from the stability boundary. The obtained results apply to the class of symmetric multivariable control objects. The approach to assessing the sustainability of multivariable system regulation can be effectively

  1. Geophysical Methods for Monitoring Soil Stabilization Processes

    Science.gov (United States)

    Soil stabilization involves methods used to turn unconsolidated and unstable soil into a stiffer, consolidated medium that could support engineered structures, alter permeability, change subsurface flow, or immobilize contamination through mineral precipitation. Among the variety...

  2. Thermal stability of soy-based polyurethanes

    Directory of Open Access Journals (Sweden)

    Luciane L. Monteavaro

    2005-06-01

    Full Text Available New types of polyurethanes were prepared by reacting diisocyanates and formiated soy polyols with different OH functionalities. Thermal properties and degradation kinetics were investigated by TGA. All prepared PU's showed at least two-weight loss steps, the first one, around 210 °C. Thermal stability of these PUs depends strongly on urethane groups per unit volume and an increase in the weight loss was observed as a result of the increased amount of urethane groups. Degradation kinetics behavior of the soy-based polyurethanes was investigated according to the Flynn method. Different average activation energy values were obtained from isothermal and isoconversional curves, 140.6 KJ/mol and 62.8 KJ/mol, respectively, indicating the complexity of the PUs degradation process.

  3. Signal Processing Methods for Liquid Rocket Engine Combustion Spontaneous Stability and Rough Combustion Assessments

    Science.gov (United States)

    Kenny, R. Jeremy; Casiano, Matthew; Fischbach, Sean; Hulka, James R.

    2012-01-01

    Liquid rocket engine combustion stability assessments are traditionally broken into three categories: dynamic stability, spontaneous stability, and rough combustion. This work focuses on comparing the spontaneous stability and rough combustion assessments for several liquid engine programs. The techniques used are those developed at Marshall Space Flight Center (MSFC) for the J-2X Workhorse Gas Generator program. Stability assessment data from the Integrated Powerhead Demonstrator (IPD), FASTRAC, and Common Extensible Cryogenic Engine (CECE) programs are compared against previously processed J-2X Gas Generator data. Prior metrics for spontaneous stability assessments are updated based on the compilation of all data sets.

  4. Stability of prebiotic, laminaran oligosaccharide under food processing conditions

    Science.gov (United States)

    Chamidah, A.

    2018-04-01

    Prebiotic stability tests on laminaran oligosaccharide under food processing conditions were urgently performed to determine the ability of prebiotics deal with processing. Laminaran, oligosaccharide is produced from enzymatic hydrolysis. To further apply this prebiotic, it is necessary to test its performance on food processing. Single prebiotic or in combination with probiotic can improve human digestive health. The effectiveness evaluation of prebiotic should be taken into account in regards its chemical and functional stabilities. This study aims to investigate the stability of laminaran, oligosaccharide under food processing condition.

  5. Study of stabilization/solidification processes (of solid porous wastes) based on hydraulic or bituminous binders; Etude des procedes de stabilisation/solidification (des dechets solides poreux) a base de liants hydrauliques ou de liants bitumineux

    Energy Technology Data Exchange (ETDEWEB)

    Sing-Teniere, Ch.

    1998-02-01

    The first part of this thesis presents the regulatory framework and the technical context linked with the study of stabilized/solidified wastes and with the evaluation of stabilization/solidification processes. A presentation of the two type of ultimate wastes under study (a used catalyst and an activated charcoal) and an analysis of the processes is given. The second part is devoted to the experimental characterization of both types of porous wastes. The third part deals with the processing of such wastes using an hydraulic binder. The study stresses on both on the stabilization/solidification efficiency of the process and on the conditions of its implementation. The same work is made for a process that uses a bituminous binder. Some choice criteria for the selection of the better process are deduced from the examination of the overall data collected. The waste characterization methodology is applied six times: two times for the raw wastes, two times for the same wastes processed with an hydraulic binder, and two times for the same wastes processed with a bituminous binder. (J.S.)

  6. Stability of inflation processes with polymer melts

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz; Eriksson, Torbjörn Gerhard; Hassager, Ole

    2002-01-01

    The production process Blow-moulding is used to produce different kinds of bottles in plastic. The final stage in this process is the inflation of some kind of (extruded or injection moulded) cylinder outward against the wall of the mould. This creates the final shape of the product. The inflation...... is performed applying a gas pressure into the core of the cylinder, which press the molten plastic cylinder outward. During the inflation the plastic may burst. The occurrence of this burst, or break, puts a limit on the possibility to produce a specified product at some, or all, processing conditions. Here...

  7. Stability of traditionally processed vegetable oils and their blends ...

    African Journals Online (AJOL)

    ajol.info/index.php/ijbcs http://indexmedicus.afro.who.int. Stability of traditionally processed vegetable oils and their blends under different storage conditions. Faustine N. NGASSAPA1, Tupeligwe R. MWAISAKA2 and Stephen S. NYANDORO1*.

  8. Stability of fruit bases and chocolate fillings

    Directory of Open Access Journals (Sweden)

    Joice Natali Miquelim

    2011-03-01

    Full Text Available Syrups with high sugar content and dehydrated fruits in its composition can be added to chocolate fillings to reduce the need of artificial flavor and dyes attributing a natural appeal to the product. Fruit bases were produced with lyophilized strawberry, passion fruit, and sliced orange peel. Rheological dynamic oscillatory tests were applied to determine the products stability and tendency of shelf life. Values of G´ G´´ were found for orange flavor during the 90 days of storage. It was observed that shear stress values did not vary significantly suggesting product stability during the studied period. For all fillings, it was found a behavior similar to the fruit base indicating that it has great influence on the filling behavior and its stability. The use of a sugar matrix in fillings provided good shelf life for the fruit base, which could be kept under room temperature conditions for a period as long as one year. The good stability and storage conditions allow the use of fruit base for handmade products as well as for industrialized products.

  9. Stabilization of Fast Pyrolysis Oil: Post Processing Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.; Lee, Suh-Jane; Hart, Todd R.

    2012-03-01

    UOP LLC, a Honeywell Company, assembled a comprehensive team for a two-year project to demonstrate innovative methods for the stabilization of pyrolysis oil in accordance with DOE Funding Opportunity Announcement (FOA) DE-PS36-08GO98018, Biomass Fast Pyrolysis Oil (Bio-oil) Stabilization. In collaboration with NREL, PNNL, the USDA Agricultural Research Service (ARS), Pall Fuels and Chemicals, and Ensyn Corporation, UOP developed solutions to the key technical challenges outlined in the FOA. The UOP team proposed a multi-track technical approach for pyrolysis oil stabilization. Conceptually, methods for pyrolysis oil stabilization can be employed during one or both of two stages: (1) during the pyrolysis process (In Process); or (2) after condensation of the resulting vapor (Post-Process). Stabilization methods fall into two distinct classes: those that modify the chemical composition of the pyrolysis oil, making it less reactive; and those that remove destabilizing components from the pyrolysis oil. During the project, the team investigated methods from both classes that were suitable for application in each stage of the pyrolysis process. The post processing stabilization effort performed at PNNL is described in this report. The effort reported here was performed under a CRADA between PNNL and UOP, which was effective on March 13, 2009, for 2 years and was subsequently modified March 8, 2011, to extend the term to December 31, 2011.

  10. High Electron Mobility and Ambient Stability in Solution-Processed Perylene-Based Organic Field-Effect Transistors : origin of the enhanced electrical performances

    NARCIS (Netherlands)

    Piliego, Claudia; Jarzab, Dorota; Gigli, Giuseppe; Chen, Zhihua; Facchetti, Antonio; Loi, Maria Antonietto

    2009-01-01

    Bottom-contact n-channel OFETs basedon spin-coated films of N,N'-1H,1H-perfluorobutyl dicyanoperylenediimide (PDI-FCN(2)) exhibit a saturation-regime mobility of 0.15 cm(2) V(-1) s(-1) in vacuum and good air stability. These performances are attributed to the high crystallinity and to the edge-on

  11. Process stationarity and reliability of trunk postural stability.

    Science.gov (United States)

    Lee, HyunWook; Granata, Kevin P

    2008-07-01

    Empirical assessments of torso stability can be estimated from postural variability and nonlinear analyses of seated balance tasks. However, processing methods require sufficient signal duration and test-retest experiments require the assessment must be reliable. Our goal was to characterize the reliability and establish the trial duration for torso stability assessment. Kinetic and kinematic data were recorded while subjects maintained a seated posture on a wobbly seat pan. Stability was evaluated from dynamic variability and nonlinear stability analyses. Process stationarity of the measured signals characterized the minimum necessary trial duration. Intra-class correlations measured within-session and between-session reliability. Trial duration necessary to achieve process stationarity was 30.2 s. Shorter time to stationarity was observed with measures that included multi-dimensional movement behavior. Summary statistics of movement variability demonstrated moderate intra-session reliability, intra-class correlation=0.64 (range 0.38-0.87). Inter-session reliability for movement variance was moderate, intra-class correlation=0.42 (range 0.22-0.64). Nonlinear stability measures typically performed better than estimates of variability with inter-session reliability as high as intra-class correlation=0.83. Process stationarity and reliability were improved in more difficult balance conditions. To adequately capture torso dynamics during the stability assessment the trial duration should be at least 30 s. Moderate to excellent test-retest reliability can be achieved in intra-session analyses, but more repeated measurements are required for inter-session comparisons. Stability diffusion exponents, H(S), and the Lyapunov exponents provide excellent measures for intra-session analyses, while H(S) provides excellent inter-session comparisons of torso stability.

  12. Strong practical stability and stabilization of uncertain discrete linear repetitive processes

    Czech Academy of Sciences Publication Activity Database

    Dabkowski, Pavel; Galkowski, K.; Bachelier, O.; Rogers, E.; Kummert, A.; Lam, J.

    2013-01-01

    Roč. 20, č. 2 (2013), s. 220-233 ISSN 1070-5325 R&D Projects: GA MŠk(CZ) 1M0567 Institutional research plan: CEZ:AV0Z10750506 Institutional support: RVO:67985556 Keywords : strong practical stability * stabilization * uncertain discrete linear repetitive processes * linear matrix inequality Subject RIV: BC - Control Systems Theory Impact factor: 1.424, year: 2013 http://onlinelibrary.wiley.com/doi/10.1002/nla.812/abstract

  13. Compressive strength and hydrolytic stability of fly ash based geopolymers

    Directory of Open Access Journals (Sweden)

    Nikolić Irena

    2013-01-01

    Full Text Available The process of geopolymerization involves the reaction of solid aluminosilicate materials with highly alkaline silicate solution yielding an aluminosilicate inorganic polymer named geopolymer, which may be successfully applied in civil engineering as a replacement for cement. In this paper we have investigated the influence of synthesis parameters: solid to liquid ratio, NaOH concentration and the ratio of Na2SiO3/NaOH, on the mechanical properties and hydrolytic stability of fly ash based geopolymers in distilled water, sea water and simulated acid rain. The highest value of compressive strength was obtained using 10 mol dm-3 NaOH and at the Na2SiO3/NaOH ratio of 1.5. Moreover, the results have shown that mechanical properties of fly ash based geopolymers are in correlation with their hydrolytic stability. Factors that increase the compressive strength also increase the hydrolytic stability of fly ash based geopolymers. The best hydrolytic stability of fly ash based geopolymers was shown in sea water while the lowest stability was recorded in simulated acid rain. [Projekat Ministarstva nauke Republike Srbije, br. 172054 i Nanotechnology and Functional Materials Center, funded by the European FP7 project No. 245916

  14. Operational stability prediction in milling based on impact tests

    Science.gov (United States)

    Kiss, Adam K.; Hajdu, David; Bachrathy, Daniel; Stepan, Gabor

    2018-03-01

    Chatter detection is usually based on the analysis of measured signals captured during cutting processes. These techniques, however, often give ambiguous results close to the stability boundaries, which is a major limitation in industrial applications. In this paper, an experimental chatter detection method is proposed based on the system's response for perturbations during the machining process, and no system parameter identification is required. The proposed method identifies the dominant characteristic multiplier of the periodic dynamical system that models the milling process. The variation of the modulus of the largest characteristic multiplier can also be monitored, the stability boundary can precisely be extrapolated, while the manufacturing parameters are still kept in the chatter-free region. The method is derived in details, and also verified experimentally in laboratory environment.

  15. Assessing Grasp Stability Based on Learning and Haptic Data

    DEFF Research Database (Denmark)

    Bekiroglu, Yasemin; Laaksonen, Janne; Jørgensen, Jimmy Alison

    2011-01-01

    An important ability of a robot that interacts with the environment and manipulates objects is to deal with the uncertainty in sensory data. Sensory information is necessary to, for example, perform online assessment of grasp stability. We present methods to assess grasp stability based on haptic...... measurements from fingertips; and joint configuration of the hand. Sensory knowledge affects the success of the grasping process both in the planning stage (before a grasp is executed) and during the execution of the grasp (closed-loop online control). In this paper, we study both of these aspects. We propose...

  16. Automation for a base station stability testing

    OpenAIRE

    Punnek, Elvis

    2016-01-01

    This Batchelor’s thesis was commissioned by Oy LM Ericsson Ab Oulu. The aim of it was to help to investigate and create a test automation solution for the stability testing of the LTE base station. The main objective was to create a test automation for a predefined test set. This test automation solution had to be created for specific environments and equipment. This work included creating the automation for the test cases and putting them to daily test automation jobs. The key factor...

  17. Production of Low Cost Carbon-Fiber through Energy Optimization of Stabilization Process

    Directory of Open Access Journals (Sweden)

    Gelayol Golkarnarenji

    2018-03-01

    Full Text Available To produce high quality and low cost carbon fiber-based composites, the optimization of the production process of carbon fiber and its properties is one of the main keys. The stabilization process is the most important step in carbon fiber production that consumes a large amount of energy and its optimization can reduce the cost to a large extent. In this study, two intelligent optimization techniques, namely Support Vector Regression (SVR and Artificial Neural Network (ANN, were studied and compared, with a limited dataset obtained to predict physical property (density of oxidative stabilized PAN fiber (OPF in the second zone of a stabilization oven within a carbon fiber production line. The results were then used to optimize the energy consumption in the process. The case study can be beneficial to chemical industries involving carbon fiber manufacturing, for assessing and optimizing different stabilization process conditions at large.

  18. Stability of minoxidil in Espumil foam base.

    Science.gov (United States)

    Geiger, Christine M; Sorenson, Bridget; Whaley, Paul A

    2013-01-01

    Minoxidil is a drug used to stimulate hair growth and to slow balding. It is marketed under a number of trade names, including Rogaine, and is available in varying strength dose forms from a number of generic manufacturers. Minoxidil is available in oral and topical forms. In topical form, it can be applied by a metered-spray or rub-on applicator. A hydroalcoholic compounding vehicle can minimize greasiness, itching, burning, and contact dermatitis where low concentrations of ethanol and propylene glycol are present. Espumil Foam Base contains low concentrations of these ingredients and also can form a foam on topical application. Espumil's unique delivery by foam-activating packaging assures simple application to difficult-to-treat areas, and it vanishes quickly after application, keeping it in place and avoiding health skin areas. The objective of this study was to determine the stability of minoxidil in Espumil Foam Base. The studied sample was compounded into a 50-mg/mL solution and stored in a plastic foam-activating bottle at room temperature conditions. Three samples were assayed at each time point out to 90 days by a stability-indicating high-performance liquid chromatography method. The method was validated for its specificity through forced-degradation studies. The beyond-use-date is at least 90 days, based on data collected when this formulation was stored at room temperature, protected from light.

  19. Process Design Concepts for Stabilization of High Level Waste Calcine

    Energy Technology Data Exchange (ETDEWEB)

    T. R. Thomas; A. K. Herbst

    2005-06-01

    The current baseline assumption is that packaging ¡§as is¡¨ and direct disposal of high level waste (HLW) calcine in a Monitored Geologic Repository will be allowed. The fall back position is to develop a stabilized waste form for the HLW calcine, that will meet repository waste acceptance criteria currently in place, in case regulatory initiatives are unsuccessful. A decision between direct disposal or a stabilization alternative is anticipated by June 2006. The purposes of this Engineering Design File (EDF) are to provide a pre-conceptual design on three low temperature processes under development for stabilization of high level waste calcine (i.e., the grout, hydroceramic grout, and iron phosphate ceramic processes) and to support a down selection among the three candidates. The key assumptions for the pre-conceptual design assessment are that a) a waste treatment plant would operate over eight years for 200 days a year, b) a design processing rate of 3.67 m3/day or 4670 kg/day of HLW calcine would be needed, and c) the performance of waste form would remove the HLW calcine from the hazardous waste category, and d) the waste form loadings would range from about 21-25 wt% calcine. The conclusions of this EDF study are that: (a) To date, the grout formulation appears to be the best candidate stabilizer among the three being tested for HLW calcine and appears to be the easiest to mix, pour, and cure. (b) Only minor differences would exist between the process steps of the grout and hydroceramic grout stabilization processes. If temperature control of the mixer at about 80„aC is required, it would add a major level of complexity to the iron phosphate stabilization process. (c) It is too early in the development program to determine which stabilizer will produce the minimum amount of stabilized waste form for the entire HLW inventory, but the volume is assumed to be within the range of 12,250 to 14,470 m3. (d) The stacked vessel height of the hot process vessels

  20. Quality assessment of digested sludges produced by advanced stabilization processes.

    Science.gov (United States)

    Braguglia, C M; Coors, A; Gallipoli, A; Gianico, A; Guillon, E; Kunkel, U; Mascolo, G; Richter, E; Ternes, T A; Tomei, M C; Mininni, G

    2015-05-01

    The European Union (EU) Project Routes aimed to discover new routes in sludge stabilization treatments leading to high-quality digested sludge, suitable for land application. In order to investigate the impact of different enhanced sludge stabilization processes such as (a) thermophilic digestion integrated with thermal hydrolysis pretreatment (TT), (b) sonication before mesophilic/thermophilic digestion (UMT), and (c) sequential anaerobic/aerobic digestion (AA) on digested sludge quality, a broad class of conventional and emerging organic micropollutants as well as ecotoxicity was analyzed, extending the assessment beyond the parameters typically considered (i.e., stability index and heavy metals). The stability index was improved by adding aerobic posttreatment or by operating dual-stage process but not by pretreatment integration. Filterability was worsened by thermophilic digestion, either alone (TT) or coupled with mesophilic digestion (UMT). The concentrations of heavy metals, present in ranking order Zn > Cu > Pb > Cr ~ Ni > Cd > Hg, were always below the current legal requirements for use on land and were not removed during the processes. Removals of conventional and emerging organic pollutants were greatly enhanced by performing double-stage digestion (UMT and AA treatment) compared to a single-stage process as TT; the same trend was found as regards toxicity reduction. Overall, all the digested sludges exhibited toxicity to the soil bacterium Arthrobacter globiformis at concentrations about factor 100 higher than the usual application rate of sludge to soil in Europe. For earthworms, a safety margin of factor 30 was generally achieved for all the digested samples.

  1. Stability and servo-control of the crystal pulling process

    International Nuclear Information System (INIS)

    Johansen, T.H.

    1990-11-01

    The paper analyzes why the crystal pulling process needs servo-control, and how it can be implemented. Special emphasis is put on the fundamental question of inherent stability, and how to interpret the signal from a balance when the weighing method is used for cystal diameter detection. 15 refs., 13 figs

  2. Stability of traditionally processed vegetable oils and their blends ...

    African Journals Online (AJOL)

    The objective of the study was to investigate the stability of traditionally processed palm oil (PO), sunflower oil (SO) and sesame oil (SSO) and their blends as function of storage conditions by analysing their physicochemical properties which included acid value, saponification value, peroxide value, iodine value and ...

  3. Induced polarization for characterizing and monitoring soil stabilization processes

    Science.gov (United States)

    Saneiyan, S.; Ntarlagiannis, D.; Werkema, D. D., Jr.

    2017-12-01

    Soil stabilization is critical in addressing engineering problems related to building foundation support, road construction and soil erosion among others. To increase soil strength, the stiffness of the soil is enhanced through injection/precipitation of a chemical agents or minerals. Methods such as cement injection and microbial induced carbonate precipitation (MICP) are commonly applied. Verification of a successful soil stabilization project is often challenging as treatment areas are spatially extensive and invasive sampling is expensive, time consuming and limited to sporadic points at discrete times. The geophysical method, complex conductivity (CC), is sensitive to mineral surface properties, hence a promising method to monitor soil stabilization projects. Previous laboratory work has established the sensitivity of CC on MICP processes. We performed a MICP soil stabilization projects and collected CC data for the duration of the treatment (15 days). Subsurface images show small, but very clear changes, in the area of MICP treatment; the changes observed fully agree with the bio-geochemical monitoring, and previous laboratory experiments. Our results strongly suggest that CC is sensitive to field MICP treatments. Finally, our results show that good quality data alone are not adequate for the correct interpretation of field CC data, at least when the signals are low. Informed data processing routines and the inverse modeling parameters are required to produce optimal results.

  4. UNMANNED AIR VEHICLE STABILIZATION BASED ON NEURAL NETWORK REGULATOR

    Directory of Open Access Journals (Sweden)

    S. S. Andropov

    2016-09-01

    Full Text Available A problem of stabilizing for the multirotor unmanned aerial vehicle in an environment with external disturbances is researched. A classic proportional-integral-derivative controller is analyzed, its flaws are outlined: inability to respond to changing of external conditions and the need for manual adjustment of coefficients. The paper presents an adaptive adjustment method for coefficients of the proportional-integral-derivative controller based on neural networks. A neural network structure, its input and output data are described. Neural networks with three layers are used to create an adaptive stabilization system for the multirotor unmanned aerial vehicle. Training of the networks is done with the back propagation method. Each neural network produces regulator coefficients for each angle of stabilization as its output. A method for network training is explained. Several graphs of transition process on different stages of learning, including processes with external disturbances, are presented. It is shown that the system meets stabilization requirements with sufficient number of iterations. Described adjustment method for coefficients can be used in remote control of unmanned aerial vehicles, operating in the changing environment.

  5. Banking Consolidation Process and Impact to Financial Stability

    Directory of Open Access Journals (Sweden)

    Lina Novickytė

    2011-03-01

    Full Text Available Globalization promotes financial market participants to seek opportunities for efficient management of available resources and maximize benefits. In recent years, took place in the con­solidation process is mainly due to both macroeconomic and microeconomic factors. Most often leads to consolidation pro­cesses in order to gain economies of scale, market power and X-efficiency. Market consolidation and financial sector stability studies have shown that concentrated financial intermediaries market have a negative impact on the region/country/sector financial stability. In the future countries and regions (EU must find ways and means to smoothly manage the inevitable process of globalization under the supervision of future merger transac­tions in order to guarantee the efficiency and sustainability of the financial sector. Article in Lithuanian

  6. ℋ∞ constant gain state feedback stabilization of stochastic hybrid systems with Wiener process

    Directory of Open Access Journals (Sweden)

    E. K. Boukas

    2004-01-01

    Full Text Available This paper considers the stabilization problem of the class of continuous-time linear stochastic hybrid systems with Wiener process. The ℋ∞ state feedback stabilization problem is treated. A state feedback controller with constant gain that does not require access to the system mode is designed. LMI-based conditions are developed to design the state feedback controller with constant gain that stochastically stabilizes the studied class of systems and, at the same time, achieve the disturbance rejection of a desired level. The minimum disturbance rejection is also determined. Numerical examples are given to show the usefulness of the proposed results.

  7. Analysis and assessment of STATCOM-based damping stabilizers for power system stability enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Abido, M.A. [Electrical Engineering Department, King Fahd University of Petroleum and Minerals, KFUPM Box Number 183, Dhahran 31261 (Saudi Arabia)

    2005-02-01

    Power system stability enhancement via STATCOM-based stabilizers is thoroughly investigated in this paper. This study presents a singular value decomposition (SVD)-based approach to assess and measure the controllability of the poorly damped electromechanical modes by STATCOM different control channels. The coordination among the proposed damping stabilizers and the STATCOM internal ac and dc voltage controllers has been taken into consideration. The design problem of STATCOM-based stabilizers is formulated as an optimization problem. For coordination purposes, a time domain-based multiobjective junction to improve the system stability as well as ac and dc voltage regulation is proposed. Then, a real-coded genetic algorithm (RCGA) is employed to search for optimal stabilizer parameters. This aims to enhance both rotor angle stability and voltage regulation of the power system. The proposed stabilizers are tested on a weakly connected power system with different disturbances and loading conditions. The nonlinear simulation results show the effectiveness and robustness of the proposed control schemes over a wide range of loading conditions. It is also observed that the proposed STATCOM-based damping stabilizers extend the critical clearing time (CCT) and enhance greatly the power system transient stability.

  8. Bifurcation and stability analysis of a nonlinear milling process

    Science.gov (United States)

    Weremczuk, Andrzej; Rusinek, Rafal; Warminski, Jerzy

    2018-01-01

    Numerical investigations of milling operations dynamics are presented in this paper. A two degree of freedom nonlinear model is used to study workpiece-tool vibrations. The analyzed model takes into account both flexibility of the tool and the workpiece. The dynamics of the milling process is described by the discontinuous ordinary differential equation with time delay, which can cause process instability. First, stability lobes diagrams are created on the basis of the parameters determined in impact test of an end mill and workpiece. Next, the bifurcations diagrams are performed for different values of rotational speeds.

  9. Investigation of the deformation stability in the incremental sheet forming process

    Directory of Open Access Journals (Sweden)

    Ai S.

    2015-01-01

    Full Text Available Incremental sheet forming (ISF is a highly versatile and flexible process for rapid manufacturing of complex sheet metal parts. One of the unique characters of the ISF process is the improved formability comparing to conventional sheet forming process. This may be due to the localized deformation nature, which increases the deformation stability in the ISF process. Although many hypotheses have been proposed, there is no direct modelling and calculation of the ISF deformation stability. Aiming to obtain a better understanding of the ISF process, an analytical model was developed to investigate and analyse the material deformation stability in this work. Based on the analytical evaluation of stress variations and force equilibrium, a mathematical relationship between the maximum forming angle and the process stability condition was established. To validate the developed model, experiments were carried out by forming a hyperbolic part made of AA1100 material. The maximum forming angle, as an indicator to the ISF formability, was employed compare the analytical evaluation and experimental result. It was found that the ISF deformation stability is one of the key factors that affect the ISF formability.

  10. Genetic algorithm based reactive power dispatch for voltage stability improvement

    Energy Technology Data Exchange (ETDEWEB)

    Devaraj, D. [Department of Electrical and Electronics, Kalasalingam University, Krishnankoil 626 190 (India); Roselyn, J. Preetha [Department of Electrical and Electronics, SRM University, Kattankulathur 603 203, Chennai (India)

    2010-12-15

    Voltage stability assessment and control form the core function in a modern energy control centre. This paper presents an improved Genetic algorithm (GA) approach for voltage stability enhancement. The proposed technique is based on the minimization of the maximum of L-indices of load buses. Generator voltages, switchable VAR sources and transformer tap changers are used as optimization variables of this problem. The proposed approach permits the optimization variables to be represented in their natural form in the genetic population. For effective genetic processing, the crossover and mutation operators which can directly deal with the floating point numbers and integers are used. The proposed algorithm has been tested on IEEE 30-bus and IEEE 57-bus test systems and successful results have been obtained. (author)

  11. Stability improvement of induction generator-based wind turbine systems

    DEFF Research Database (Denmark)

    Chen, Zhe; Hu, Y.; Blaabjerg, Frede

    2007-01-01

    The stability improvement of induction-generator-based wind turbine systems under power system fault conditions has been studied. Two types of generators are considered, namely rotor short-circuited induction generators and dynamic slip-controlled wound rotor induction generators. The factors...... affecting the stability are analysed. The characteristics of the induction-generator-based wind turbines are described, and possible methods of improving stability of the wind generators are discussed. The system modelling is presented, and then the discussed methods of improving stability are investigated....... Simulation results have been presented and the effectiveness of the stability improvement methods has been discussed....

  12. Application of magnetic iron oxide nanoparticles in stabilization process of biological molecules

    Directory of Open Access Journals (Sweden)

    Mohammad Hossien Salmani

    2017-07-01

    Conclusion: Co-precipitation method is an easy way to prepare magnetic nanoparticles of iron with a large surface and small particle size, which increases the ability of these particles to act as a suitable carrier for enzyme stabilization. Adequate modification of the surface of these nanoparticles enhances their ability to bind to biological molecules. The immobilized protein or enzyme on magnetic nanoparticles are more stable against structural changes, temperature and pH in comparison with un-stabilized structures, and it is widely used in various sciences, including protein isolation and purification, pharmaceutical science, and food analysis. Stabilization based on the covalent bonds and physical absorption is nonspecific, which greatly limits their functionality. The process of stabilization through bio-mediums provide a new method to overcome the selectivity problem.

  13. Stability improvement of induction generator-based wind turbine systems

    DEFF Research Database (Denmark)

    Chen, Zhe; Hu, Y.; Blaabjerg, Frede

    2007-01-01

    affecting the stability are analysed. The characteristics of the induction-generator-based wind turbines are described, and possible methods of improving stability of the wind generators are discussed. The system modelling is presented, and then the discussed methods of improving stability are investigated......The stability improvement of induction-generator-based wind turbine systems under power system fault conditions has been studied. Two types of generators are considered, namely rotor short-circuited induction generators and dynamic slip-controlled wound rotor induction generators. The factors...

  14. Production process stability - core assumption of INDUSTRY 4.0 concept

    Science.gov (United States)

    Chromjakova, F.; Bobak, R.; Hrusecka, D.

    2017-06-01

    Today’s industrial enterprises are confronted by implementation of INDUSTRY 4.0 concept with basic problem - stabilised manufacturing and supporting processes. Through this phenomenon of stabilisation, they will achieve positive digital management of both processes and continuously throughput. There is required structural stability of horizontal (business) and vertical (digitized) manufacturing processes, supported through digitalised technologies of INDUSTRY 4.0 concept. Results presented in this paper based on the research results and survey realised in more industrial companies. Following will described basic model for structural process stabilisation in manufacturing environment.

  15. Folates in foods: reactivity, stability during processing, and nutritional implications.

    Science.gov (United States)

    Hawkes, J G; Villota, R

    1989-01-01

    Nutritional deficiencies are eminent at all socioeconomic levels of the world population and have created a critical need for a reevaluation of the nutritional quality of the food supply. A particular group of vitamers, collectively referred to as folates, has received a great deal of attention due to their significance in human metabolism, their prevalent deficiency worldwide, as well as their complexity of analysis. Severe folate deficiency may result in megaloblastic anemia and is generally attributed to low dietary intake, although it may also result from malabsorption. Such concerns have instigated increased interest in food-fortification programs. In order to ensure appropriate levels of nutrient fortification and optimization of food processes for maximum folate retention, it is of great importance to have a basic understanding of the kinetic behavior of individual vitamers with respect to processing parameters and various environmental conditions. This article reviews kinetic stability of folates as affected by processing conditions, discusses problems associated with current methodology for folate analyses, and integrates this information with the nutritional aspects of folates.

  16. Phases stability of shape memory alloys Cu based under irradiation

    International Nuclear Information System (INIS)

    Zelaya, Maria Eugenia

    2006-01-01

    The effects of irradiation on the relative phase stability of phases related by a martensitic transformation in copper based shape memory alloys were studied in this work.Different kind of particles and energies were employed in the irradiation experiments.The first kind of irradiation was performed with 2,6 MeV electrons, the second one with 170 keV and 300 keV Cu ions and the third one with swift heavy ions (Kr, Xe, Au) with energies between 200 and 600 MeV.Stabilization of the 18 R martensite in Cu-Zn-Al-Ni induced by electron irradiation was studied.The results were compared to those of the stabilization induced by quenching and ageing in the same alloy, and the ones obtained by irradiation in 18 R-Cu-Zn-Al alloys.The effects of Cu irradiation over b phase were analyzed with several electron microscopy techniques including: scanning electron microscopy (S E M), high resolution electron microscopy (H R E M), micro diffraction and X-ray energy dispersive spectroscopy (E D S). Structural changes in Cu-Zn-Al b phase into a closed packed structure were induced by Cu ion implantation.The closed packed structures depend on the irradiation fluence.Based on these results, the interface between these structures (closed packed and b) and the stability of disordered phases were analyzed. It was also compared the evolution of long range order in the Cu-Zn-Al and in the Cu-Zn-Al-Ni b phase as a function of fluence.The evolution of the g phase was also compared. Both results were discussed in terms of the mobility of irradiation induced point defects.Finally, the effects induced by swift heavy ions in b phase and 18 R martensite were studied. The results of the irradiation in b phase were qualitatively similar to those produced by irradiation with lower energies. On the contrary, nano metric defects were found in the irradiated 18 R martensite.These defects were characterized by H R E M.The characteristic contrast of the defects was associated to a local change in the

  17. stabilization of cinder gravel with cment for base course

    African Journals Online (AJOL)

    Girma Berhanu

    design standards for heavily trafficked base course without adding fine soils is found to be 7 % cement. However, this high cement requirement was reduced to 5% cement which is a practical value by mechanically stabilizing cinder gravel with 12 % of fine soils before cement stabilization. Nevertheless, the performance of ...

  18. Power System Transient Stability Based on Data Mining Theory

    Science.gov (United States)

    Cui, Zhen; Shi, Jia; Wu, Runsheng; Lu, Dan; Cui, Mingde

    2018-01-01

    In order to study the stability of power system, a power system transient stability based on data mining theory is designed. By introducing association rules analysis in data mining theory, an association classification method for transient stability assessment is presented. A mathematical model of transient stability assessment based on data mining technology is established. Meanwhile, combining rule reasoning with classification prediction, the method of association classification is proposed to perform transient stability assessment. The transient stability index is used to identify the samples that cannot be correctly classified in association classification. Then, according to the critical stability of each sample, the time domain simulation method is used to determine the state, so as to ensure the accuracy of the final results. The results show that this stability assessment system can improve the speed of operation under the premise that the analysis result is completely correct, and the improved algorithm can find out the inherent relation between the change of power system operation mode and the change of transient stability degree.

  19. Power system stabilizers based on modern control techniques

    Energy Technology Data Exchange (ETDEWEB)

    Malik, O.P.; Chen, G.P.; Zhang, Y.; El-Metwally, K. [Calgary Univ., AB (Canada). Dept. of Electrical and Computer Engineering

    1994-12-31

    Developments in digital technology have made it feasible to develop and implement improved controllers based on sophisticated control techniques. Power system stabilizers based on adaptive control, fuzzy logic and artificial networks are being developed. Each of these control techniques possesses unique features and strengths. In this paper, the relative performance of power systems stabilizers based on adaptive control, fuzzy logic and neural network, both in simulation studies and real time tests on a physical model of a power system, is presented and compared to that of a fixed parameter conventional power system stabilizer. (author) 16 refs., 45 figs., 3 tabs.

  20. Stability of auditory discrimination and novelty processing in physiological aging.

    Science.gov (United States)

    Raggi, Alberto; Tasca, Domenica; Rundo, Francesco; Ferri, Raffaele

    2013-01-01

    Complex higher-order cognitive functions and their possible changes with aging are mandatory objectives of cognitive neuroscience. Event-related potentials (ERPs) allow investigators to probe the earliest stages of information processing. N100, Mismatch negativity (MMN) and P3a are auditory ERP components that reflect automatic sensory discrimination. The aim of the present study was to determine if N100, MMN and P3a parameters are stable in healthy aged subjects, compared to those of normal young adults. Normal young adults and older participants were assessed using standardized cognitive functional instruments and their ERPs were obtained with an auditory stimulation at two different interstimulus intervals, during a passive paradigm. All individuals were within the normal range on cognitive tests. No significant differences were found for any ERP parameters obtained from the two age groups. This study shows that aging is characterized by a stability of the auditory discrimination and novelty processing. This is important for the arrangement of normative for the detection of subtle preclinical changes due to abnormal brain aging.

  1. Stability of Auditory Discrimination and Novelty Processing in Physiological Aging

    Directory of Open Access Journals (Sweden)

    Alberto Raggi

    2013-01-01

    Full Text Available Complex higher-order cognitive functions and their possible changes with aging are mandatory objectives of cognitive neuroscience. Event-related potentials (ERPs allow investigators to probe the earliest stages of information processing. N100, Mismatch negativity (MMN and P3a are auditory ERP components that reflect automatic sensory discrimination. The aim of the present study was to determine if N100, MMN and P3a parameters are stable in healthy aged subjects, compared to those of normal young adults. Normal young adults and older participants were assessed using standardized cognitive functional instruments and their ERPs were obtained with an auditory stimulation at two different interstimulus intervals, during a passive paradigm. All individuals were within the normal range on cognitive tests. No significant differences were found for any ERP parameters obtained from the two age groups. This study shows that aging is characterized by a stability of the auditory discrimination and novelty processing. This is important for the arrangement of normative for the detection of subtle preclinical changes due to abnormal brain aging.

  2. Theoretical bases on thermal stability of layered metallic systems

    International Nuclear Information System (INIS)

    Kadyrzhanov, K.K.; Rusakov, V.S.; Turkebaev, T.Eh.; Zhankadamova, A.M.; Ensebaeva, M.Z.

    2003-01-01

    The paper is dedicated to implementation of the theoretical bases for layered metallic systems thermal stabilization. The theory is based on the stabilization mechanism expense of the intermediate two-phase field formation. As parameters of calculated model are coefficients of mutual diffusion and inclusions sizes of generated phases in two-phase fields. The stabilization time dependence for beryllium-iron (Be (1.1 μm)-Fe(5.5 μm)) layered system from iron and beryllium diffusion coefficients, and inclusions sizes is shown as an example. Conclusion about possible mechanisms change at transition from microscopic consideration to the nano-crystal physics level is given

  3. Stability of added iodine in processed cereal foods.

    Science.gov (United States)

    Thomson, B M

    2009-01-01

    The stability of iodine from iodized salt was measured in white bread, grain bread, sweet biscuits and the breakfast cereals, Weetbix (a flaked, pressed, wheat product), Ricies (a puffed rice product) and toasted muesli, as part of the New Zealand Government's initiatives to address the public health issue of low iodine intake by most New Zealanders. Triplicate runs of each product were manufactured by commercial food manufacturers between September 2006 and May 2007 with iodized and non-iodized salt. Triplicate samples were taken at various steps during processing of each food and analysed for moisture and iodine content. Iodine concentration was determined by inductively coupled plasma-mass spectrometry following an alkaline digestion. Iodine, at the equivalent of 25-65 mg of iodine per kg salt, was 100% retained in each of the selected foods from the time of mixing to the final product. These results imply that all iodine added via salt at the time of manufacture is available for consumption but not necessarily bioavailable. These data can be used for modelling the impact of strategies to increase iodine exposure. Salt as an ingredient is not a good predictor of iodine intake due to the inhomogeneity of iodine in iodized salt.

  4. Extending the Stabilized Supralinear Network model for binocular image processing.

    Science.gov (United States)

    Selby, Ben; Tripp, Bryan

    2017-06-01

    The visual cortex is both extensive and intricate. Computational models are needed to clarify the relationships between its local mechanisms and high-level functions. The Stabilized Supralinear Network (SSN) model was recently shown to account for many receptive field phenomena in V1, and also to predict subtle receptive field properties that were subsequently confirmed in vivo. In this study, we performed a preliminary exploration of whether the SSN is suitable for incorporation into large, functional models of the visual cortex, considering both its extensibility and computational tractability. First, whereas the SSN receives abstract orientation signals as input, we extended it to receive images (through a linear-nonlinear stage), and found that the extended version behaved similarly. Secondly, whereas the SSN had previously been studied in a monocular context, we found that it could also reproduce data on interocular transfer of surround suppression. Finally, we reformulated the SSN as a convolutional neural network, and found that it scaled well on parallel hardware. These results provide additional support for the plausibility of the SSN as a model of lateral interactions in V1, and suggest that the SSN is well suited as a component of complex vision models. Future work will use the SSN to explore relationships between local network interactions and sophisticated vision processes in large networks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Lactose in dairy ingredients: Effect on processing and storage stability.

    Science.gov (United States)

    Huppertz, Thom; Gazi, Inge

    2016-08-01

    Lactose is the main carbohydrate in the milk of most species. It is present in virtually all dry dairy ingredients, with levels ranging from lactose powders. The presence of lactose has a strong effect on ingredient processing and stability. Lactose can negatively influence powder properties and lead to undesirable effects, such as the stickiness of powder resulting in fouling during drying, or caking and related phenomena during storage. In addition, being a reducing carbohydrate, lactose can also participate in the Maillard reaction with free amino groups of proteins, peptides, and free AA. In this review, the influence of the presence (or absence) of lactose on physiochemical properties of dairy ingredients is reviewed, with particular emphasis on behavior during processing and storage. Particularly important features in this respect are whether lactose is in the (glassy) amorphous phase or in the crystalline phase, which is strongly affected by precrystallization conditions (e.g., in lactose, permeate, and whey powders) and by drying conditions. Furthermore, the moisture content and water activity of the ingredients are important parameters to consider, as they determine both mobility and reactivity, influencing Maillard reactions and concomitant browning, the crystallization of amorphous lactose during storage of dairy ingredients, glass transitions temperatures, and associated stickiness and caking phenomena. For the stickiness and caking, a crucial aspect to take into account is powder particle surface composition in relation to the bulk powder. Lactose is typically underrepresented at the powder surface, as a result of which deviations between observed lactose-induced caking and stickiness temperatures, and determined glass transition temperatures arise. By considering lactose as an integral part of ingredient composition along with all other compositional and environmental properties, lactose behavior in dairy ingredients can be understood, controlled, and

  6. Enzyme based soil stabilization for unpaved road construction

    Directory of Open Access Journals (Sweden)

    Renjith Rintu

    2017-01-01

    Full Text Available Enzymes as soil stabilizers have been successfully used in road construction in several countries for the past 30 years. However, research has shown that the successful application of these enzymes is case specific, emphasizing that enzyme performance is dependent on subgrade soil type, condition and the type of enzyme used as the stabilizer. A universal standard or a tool for road engineers to assess the performance of stabilized unbound pavements using well-established enzymes is not available to date. The research aims to produce a validated assessment tool which can be used to predict strength enhancement within a generalized statistical framework. The objective of the present study is to identify new materials for developing the assessment tool which supports enzyme based stabilization, as well as to identify the correct construction sequence for such new materials. A series of characterization tests were conducted on several soil types obtained from proposed construction sites. Having identified the suitable soil type to mix with the enzyme, a trial road construction has been performed to investigate the efficiency of the enzyme stabilization along with the correct construction sequence. The enzyme stabilization has showed significant improvement of the road performance as was evidenced from the test results which were based on site soil obtained before and after stabilization. The research will substantially benefit the road construction industry by not only replacing traditional construction methods with economical/reliable approaches, but also eliminating site specific tests required in current practice of enzyme based road construction.

  7. Stabilize ash using Clemson's sintering process (Part 1 - Phase 1 results): Mixed waste fly ash stabilization. Innovative technology summary report

    International Nuclear Information System (INIS)

    1998-12-01

    Incineration of applicable Department of Energy (DOE) mixed wastes has produced a secondary waste stream of radioactive and Resource Conservation and Recovery Act (RCRA) hazardous fly ash that also requires treatment before land disposal. Unlike bottom ash, fly ash usually contains constituents making efficient stabilization difficult. For example, fly ash from the DOE Waste Experimental Reduction Facility (WERF) incinerator at the Idaho National Engineering and Environmental Laboratory (INEEL) contains volatile metals, metal salts, high concentrations of zinc, and unburned organic residues. All of these constituents can effect the stabilization process. The Department of Energy, and in particular the Mixed Waste Focus Area (MWFA) of EM-50, has stated the need for improved stabilization methods would accept a higher ash waste loading while meeting waste form disposal criteria. These alternative stabilization technologies should include delivery systems to minimize worker exposure and minimize secondary waste generation, while maximizing operational flexibility and radionuclide containment. Currently, the standard practice for stabilizing ash is mixing with Portland cement at room temperature. This standard practice produces a significant increase of waste material volume or has difficulty in adequately stabilizing the components in the fly ash to ensure regulatory requirements are consistently satisfied. To address these fly ash stabilization shortcomings, the MWFA, a DOE/EM-50 program, invested in the development of several fly ash stabilization alternatives, including the Clemson University sintering method

  8. Stabilization of Multiple Unstable Modes for Small-Scale Inverter-Based Power Systems with Impedance-Based Stability Analysis

    DEFF Research Database (Denmark)

    Yoon, Changwoo; Wang, Xiongfei; Bak, Claus Leth

    2015-01-01

    This paper investigates the harmonic stability of small-scale inverter-based power systems. A holistic procedure to assess the contribution of each inverter to the system stability is proposed by means of using the impedancebased stability criterion. Multiple unstable modes can be identified step......-by-step coming from the interactions among inverters and passive networks. Compared to the conventional system stability analysis, the approach is easy to implement and avoids the effect of potential unstable system dynamics on the impedance ratio derived for the stability analysis. PSCAD/ EMTDC simulations...... of a Cigre LV network Benchmark system with multiple renewable energy sources are carried out. The results confirm the validity of the proposed approach....

  9. Stability of organometallic compounds in processes of their synthesis and decomposition

    International Nuclear Information System (INIS)

    Domrachev, G.A.; Zakharov, L.N.; Shevelev, Yu.A.

    1985-01-01

    From common positions critically considered is the notion of stability of isolated molecule of organometallic compound (OMC) as well as of the systems including OMC and products of their decomposition in various modular states aof aggregation, energy (electronic structure stability) and space (molecular structure stability) factors of OMC stability and their manifestation under different conditions. Various aspects of OMC stability during their synthesis-decomposition processes proceeding under the conditions: thermal reactions with participation of uncharged (neutral) particles of OMC and decomposition products; electron impact or electric current effect with ionized particles participation, electromagnetic radiation effect are discussed. The necessity in complex solution of the OMC stability problem is pointed out

  10. Stability Analysis of Neural Networks-Based System Identification

    Directory of Open Access Journals (Sweden)

    Talel Korkobi

    2008-01-01

    Full Text Available This paper treats some problems related to nonlinear systems identification. A stability analysis neural network model for identifying nonlinear dynamic systems is presented. A constrained adaptive stable backpropagation updating law is presented and used in the proposed identification approach. The proposed backpropagation training algorithm is modified to obtain an adaptive learning rate guarantying convergence stability. The proposed learning rule is the backpropagation algorithm under the condition that the learning rate belongs to a specified range defining the stability domain. Satisfying such condition, unstable phenomena during the learning process are avoided. A Lyapunov analysis leads to the computation of the expression of a convenient adaptive learning rate verifying the convergence stability criteria. Finally, the elaborated training algorithm is applied in several simulations. The results confirm the effectiveness of the CSBP algorithm.

  11. Interactional processes for stabilizing conceptual coherences in physics

    Science.gov (United States)

    Frank, Brian W.; Scherr, Rachel E.

    2012-12-01

    Research in student knowledge and learning of science has typically focused on explaining conceptual change. Recent research, however, documents the great degree to which student thinking is dynamic and context-sensitive, implicitly calling for explanations not only of change but also of stability. In other words, when a pattern of student reasoning is sustained in specific moments and settings, what mechanisms contribute to sustaining it? We characterize student understanding and behavior in terms of multiple local coherences in that they may be variable yet still exhibit local stabilities. We attribute stability in local conceptual coherences to real-time activities that sustain these coherences. For example, particular conceptual understandings may be stabilized by the linguistic features of a worksheet question or by feedback from the students’ spatial arrangement and orientation. We document a group of university students who engage in multiple local conceptual coherences while thinking about motion during a collaborative learning activity. As the students shift their thinking several times, we describe mechanisms that may contribute to local stability of their reasoning and behavior.

  12. Stability of Ni–yttria stabilized zirconia anodes based on Ni-impregnation

    DEFF Research Database (Denmark)

    Klemensø, Trine; Thydén, Karl Tor Sune; Chen, Ming

    2010-01-01

    Sintering of Ni is a key stability issue for Ni–YSZ anodes, and especially infiltration based electrodes. The potential of MgO, Al2O3, TiO2, CeO2 and Ce0.90Gd0.10O1.95 (CGO10) as sintering inhibitors was investigated for infiltrated Ni based anode structures. The structures were prepared from tap...

  13. Piezo-based miniature high resolution stabilized gimbal

    Science.gov (United States)

    Karasikov, Nir; Peled, Gal; Yasinov, Roman; Yetkariov, Rita

    2016-05-01

    Piezo motors are characterized by higher mechanical power density, fast response and direct drive. These features are beneficial for miniature gimbals. A gimbal based on such motors was developed. Diameter is 58 mm, weight is 190 grams. The gimbal carries two cameras: a Flir Quark and an HD day camera. The dynamic performance is as high as 3 rad/sec velocity and 100 rad/secΛ2 acceleration. A two axes stabilization algorithm was developed, yielding 80 micro radian stabilization. Further, a panoramic image capture, at a rate of six stabilized field of views per second, was developed. The manuscript reviews the gimbal structure and open architecture, allowing adaptation to other cameras (SWIR etc.), the control algorithm and presents experimental results of stabilization and of panoramic views taken on a vibration platform and on a UAV.

  14. Mild Biomass Liquefaction Process for Economic Production of Stabilized Refinery-Ready Bio-oil

    Energy Technology Data Exchange (ETDEWEB)

    Gangwal, Santosh [Southern Research, Durham, NC (United States); Meng, Jiajia [Southern Research, Durham, NC (United States); McCabe, Kevin [Southern Research, Durham, NC (United States); Larson, Eric [Princeton Univ., NJ (United States). Princeton Environmental Inst.; Mastro, Kelly [Southern Research, Durham, NC (United States)

    2016-04-25

    Southern Research (SR) in cooperation with U.S. Department of Energy (DOE), Bioenergy Technology Office (BETO), investigated a biomass liquefaction process for economic production of stabilized refinery-ready bio-oil. The project was awarded by DOE under a Funding Opportunity Announcement (DE-FOA-0000686) for Bio-oil Stabilization and Commoditization that intended to evaluate the feasibility of using bio-oil as a potential feedstock in an existing petroleum refinery. SR investigated Topic Area 1 of the FOA at Technology Readiness Level 2-3 to develop thermochemical liquefaction technologies for producing a bio-oil feedstock from high-impact biomass that can be utilized within a petroleum refinery. Bio-oil obtained from fast pyrolysis of biomass is a green intermediate that can be further upgraded into a biofuel for blending in a petroleum refinery using a hydro-deoxygenation (HDO) route. Co-processing pyrolysis bio-oil in a petroleum refinery is an attractive approach to leverage the refinery’s existing capital. However, the petroleum industry is reluctant to accept pyrolysis bio-oil because of a lack of a standard definition for an acceptable bio-oil feedstock in existing refinery processes. Also per BETO’s multiyear program plan, fast pyrolysis-based bio-fuel is presently not cost competitive with petroleum-based transportation fuels. SR aims to develop and demonstrate a cost-effective low-severity thermal liquefaction and hydrodeoxygenation (HDO) process to convert woody biomass to stabilized bio-oils that can be directly blended with hydrotreater input streams in a petroleum refinery for production of gasoline and/or diesel range hydrocarbons. The specific project objectives are to demonstrate the processes at laboratory scale, characterize the bio-oil product and develop a plan in partnership with a refinery company to move the technology towards commercialization.

  15. Phenols and aromatic amines as thermal stabilizers in polyolefin processing

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Jan; Habicher, W. D.; Al-Malaika, S.; Zweifel, H.; Nešpůrek, Stanislav

    2001-01-01

    Roč. 176, - (2001), s. 55-63 ISSN 1022-1360. [International Conference on Polymer Modification, Degradation and Stabilization /1./. Palermo, 03.09.2000-07.09.2000] R&D Projects: GA AV ČR IAA1050901; GA MŠk ME 184; GA MŠk ME 372; GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : thermal stabilizers * phenols * aromatic amines Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.634, year: 2001

  16. Sample-path stability conditions for multiserver input-output processes

    Directory of Open Access Journals (Sweden)

    Muhammad El-Taha

    1994-01-01

    Full Text Available We extend our studies of sample-path stability to multiserver input-output processes with conditional output rates that may depend on the state of the system and other auxiliary processes. Our results include processes with countable as well as uncountable state spaces. We establish rate stability conditions for busy period durations as well as the input during busy periods. In addition, stability conditions for multiserver queues with possibly heterogeneous servers are given for the workload, attained service, and queue length processes. The stability conditions can be checked from parameters of primary processes, and thus can be verified a priori. Under the rate stability conditions, we provide stable versions of Little's formula for single server as well as multiserver queues. Our approach leads to extensions of previously known results. Since our results are valid pathwise, non-stationary as well as stationary processes are covered.

  17. Improving protein stabilization by spray drying : formulation and process development

    NARCIS (Netherlands)

    Grasmeijer, Niels

    2016-01-01

    There is an increasing interest for dried protein formulations in pharmacy. They may offer several advantages over aqueous formulations, such as ease of storage, longer shelf life, and use for solid dosage forms. However, the mechanisms underlying stabilization in the solid state are not yet fully

  18. Stability of subsystem solutions in agent-based models

    Science.gov (United States)

    Perc, Matjaž

    2018-01-01

    The fact that relatively simple entities, such as particles or neurons, or even ants or bees or humans, give rise to fascinatingly complex behaviour when interacting in large numbers is the hallmark of complex systems science. Agent-based models are frequently employed for modelling and obtaining a predictive understanding of complex systems. Since the sheer number of equations that describe the behaviour of an entire agent-based model often makes it impossible to solve such models exactly, Monte Carlo simulation methods must be used for the analysis. However, unlike pairwise interactions among particles that typically govern solid-state physics systems, interactions among agents that describe systems in biology, sociology or the humanities often involve group interactions, and they also involve a larger number of possible states even for the most simplified description of reality. This begets the question: when can we be certain that an observed simulation outcome of an agent-based model is actually stable and valid in the large system-size limit? The latter is key for the correct determination of phase transitions between different stable solutions, and for the understanding of the underlying microscopic processes that led to these phase transitions. We show that a satisfactory answer can only be obtained by means of a complete stability analysis of subsystem solutions. A subsystem solution can be formed by any subset of all possible agent states. The winner between two subsystem solutions can be determined by the average moving direction of the invasion front that separates them, yet it is crucial that the competing subsystem solutions are characterised by a proper composition and spatiotemporal structure before the competition starts. We use the spatial public goods game with diverse tolerance as an example, but the approach has relevance for a wide variety of agent-based models.

  19. Response Based Emergency Control System for Power System Transient Stability

    Directory of Open Access Journals (Sweden)

    Huaiyuan Wang

    2015-11-01

    Full Text Available A transient stability control system for the electric power system composed of a prediction method and a control method is proposed based on trajectory information. This system, which is independent of system parameters and models, can detect the transient stability of the electric power system quickly and provide the control law when the system is unstable. Firstly, system instability is detected by the characteristic concave or convex shape of the trajectory. Secondly, the control method is proposed based on the analysis of the slope of the state plane trajectory when the power system is unstable. Two control objectives are provided according to the methods of acquiring the far end point: one is the minimal cost to restore the system to a stable state; the other one is the minimal cost to limit the maximum swing angle. The simulation indicates that the mentioned transient stability control system is efficient.

  20. Chemical stability of prints made on hemp fibre based papers

    Directory of Open Access Journals (Sweden)

    Ivana Plazonić

    2016-11-01

    Full Text Available For paper industry and consequently graphic industry it is very important that fibres used in paper production provide high quality and printability of the paper. In pulp and paper industry fibres of cellulose pulp derived still predominantly from wood, but in the last few years the consumption of non-wood raw materials for that purpose has grown. This work presents research on the chemical stability of printed hemp fibre based papers to water, alcohol and alkali. Evaluation of chemical degradation on prints was determined through the spectrophotometric measurements. Deviations in colour of prints have shown that highest chemical stability provides prints made on industrially paper formed from mixture of hemp and post-consumer fibres with high share of inorganic components. Further, bleached hemp fibres in handmade 100 % hemp fibre based paper give prints with the lowest chemical stability.

  1. Solution stability of Captisol-stabilized melphalan (Evomela) versus Propylene glycol-based melphalan hydrochloride injection.

    Science.gov (United States)

    Singh, Ramsharan; Chen, Jin; Miller, Teresa; Bergren, Michael; Mallik, Rangan

    2016-12-14

    The objective of this study was to compare the stability of recently approved Captisol-stabilized propylene glycol-free melphalan injection (Evomela™) against currently marketed propylene glycol-based melphalan injection. The products were compared as reconstituted solutions in vials as well as admixture solutions prepared from normal saline in infusion bags. Evomela and propylene glycol-based melphalan injection were reconstituted in normal saline and organic custom diluent, respectively, according to their package insert instructions. The reconstituted solutions were diluted in normal saline to obtain drug admixture solutions at specific drug concentrations. Stability of the solutions was studied at room temperature by assay of melphalan and determination of melphalan-related impurities. Results show that based on the increase in total impurities in propylene glycol-based melphalan injection at 0.45 mg/mL, Evomela admixture solutions are about 5, 9, 15 and 29 times more stable at concentrations of 0.45, 1.0, 2.0 and 5.0 mg/mL, respectively. Results confirmed that reconstituted Evomela solution can be stored in the vial for up to 1 h at RT or for up to 24 h at refrigerated temperature (2-8 °C) with no significant degradation. After storage in the vial, it remains stable for an additional 3-29 h after preparation of admixture solution in infusion bags at concentrations of 0.25-5.0 mg/mL, respectively. In addition, Evomela solution in saline, at concentration of 5.0 mg/mL melphalan was bacteriostatic through 72 h storage at 2-8 °C. Formulation of melphalan with Captisol technology significantly improved stability compared to melphalan hydrochloride reconstituted with propylene-glycol based diluents.

  2. Dependence of the Stabilization of -Alumina on the Spray Process

    Czech Academy of Sciences Publication Activity Database

    Stahr, C.Ch.; Saaro, S.; Berger, L.-M.; Herrmann, M.; Dubský, Jiří; Neufuss, Karel

    2007-01-01

    Roč. 16, 5-6 (2007), s. 822-830 ISSN 1059-9630 R&D Projects: GA ČR(CZ) GA106/05/0483 Institutional research plan: CEZ:AV0Z20430508 Keywords : -Al2O3 stabilization * alumina * chromia * solid solution * X-ray diffraction Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 1.204, year: 2007

  3. Stabilizing Parametric Region of Multiloop PID Controllers for Multivariable Systems Based on Equivalent Transfer Function

    Directory of Open Access Journals (Sweden)

    Xiaoli Luan

    2016-01-01

    Full Text Available The aim of this paper is to determine the stabilizing PID parametric region for multivariable systems. Firstly, a general equivalent transfer function parameterization method is proposed to construct the multiloop equivalent process for multivariable systems. Then, based on the equivalent single loops, a model-based method is presented to derive the stabilizing PID parametric region by using the generalized Hermite-Biehler theorem. By sweeping over the entire ranges of feasible proportional gains and determining the stabilizing regions in the space of integral and derivative gains, the complete set of stabilizing PID controllers can be determined. The robustness of the design procedure against the approximation in getting the SISO plants is analyzed. Finally, simulation of a practical model is carried out to illustrate the effectiveness of the proposed technique.

  4. Influence of food processing on the immunochemical stability of celery allergens

    International Nuclear Information System (INIS)

    Jankiewicz, A.; Baltes, W.; Bögl, K.W.; Dehne, L.I.; Jamin, A.; Hoffmann, A.; Haustein, D.; Vieths, S.

    1997-01-01

    Celery roots were processed by microwave heating, cooking, drying, γ-irradiation, ultra high pressure treatment and high voltage impulse treatment. The immunochemical stabilities of the three known allergenic structures of celery were tested with sera from patients who were sensitised to celery. In addition, rabbit antisera were used to detect the allergens profilin and Api g I on celery immunoblots. The specificity and reactivity of IgE from the patients' sera were investigated by immunoblotting, by an enzyme allergosorbent test (EAST) and by dose-related IgE inhibition experiments. The results of all three methods agreed closely and indicated high antigenic and allergenic activity in native celery which was reduced by thermal processing. The heat-stability of the known celery allergens decreased in the following order: carbohydrate epitopes > profilin > Api g 1. In contrast, the allergenicity was only mildly reduced by non-thermal processing. The results obtained with human IgE were confirmed by an in vitro mediator-release assay that is based on rat basophil leukemia cells (RBL cells) which were passively sensitised with celery-specific murine IgE. With sera from mice that had been immunised with native celery, the native sample and non-thermal celery preparations elicited the strongest mediator release, whereas a weak response was obtained with samples from heat-processed celery. These results agreed closely with the data obtained in allergic patients whose IgE antibodie

  5. Assessment of read and write stability for 6T SRAM cell based on charge plasma DLTFET

    Science.gov (United States)

    Anju; Yadav, Shivendra; Sharma, Dheeraj

    2018-03-01

    To overcome the process variations due to random dopant fluctuations (RDFs) and complex annealing techniques a charge plasma based doping less TFET (CP-DLTFET) device has been proposed for designing of 6T SRAM cell. The proposed device also benefited by subthreshold slope, low leakage current, and low power supply. In this paper, to avoid the dependency of stability parameters of SRAM cell to supply voltage (Vdd), here N-curve metrics has been analyzed to determine read and write stability. Because N-curve provides stability analysis in terms of voltage and current as well as it gives combine stability analysis with the facility of an inline tester. Further, analyzing the N-curve metrics for different Vdd, cell ratio, and pull-up ratio assist in designing the configuration of transistors for the better read and write stability. Power metrics of N-curve gives the knowledge about read and write stability instead of using four metrics (SINM, SVNM, WTV, and WTI) of N-curve. Finally, in the 6T CP-DLTFET SRAM cell, read and write stability is tested by the interface trap charges (ITCs). The performance parameter of the 6T CP-DLTFET SRAM cell provides considerable read and write stability with less fabrication complexity.

  6. THE STABILITY MONITORING OF THE MANUFACTURING PROCESS OF ELECTRICAL INSULATING SYSTEMS OF TRACTION ELECTRIC MACHINES

    Directory of Open Access Journals (Sweden)

    G. V. Bezprozvannych

    2017-12-01

    Full Text Available Introduction. Electrical insulation systems make up about 0.03 % of the traction electric machines (TEM mass, but they are of exceptional importance and affect the design capabilities and manufacturing techniques of electric machines, ultimately - on their specific weight and overall dimensions, on the reliability and durability of the TEM. Purpose. The monitoring of the stability of the manufacturing process of electrical insulating systems of the TEM based on the insulation resistance measurements. Methodology. The analysis of the manufacturing process is carried out for three versions of the case of insulation of the magnetic system of the DC traction electric motor. Practical value. Construction and analysis of special graphs (charts of individual values and cumulative sums of insulation resistance, sliding range MR allow to find out whether the technological process of manufacturing electric insulating systems of traction electric machines is in a statistically controllable state.

  7. Microprocessor based image processing system

    International Nuclear Information System (INIS)

    Mirza, M.I.; Siddiqui, M.N.; Rangoonwala, A.

    1987-01-01

    Rapid developments in the production of integrated circuits and introduction of sophisticated 8,16 and now 32 bit microprocessor based computers, have set new trends in computer applications. Nowadays the users by investing much less money can make optimal use of smaller systems by getting them custom-tailored according to their requirements. During the past decade there have been great advancements in the field of computer Graphics and consequently, 'Image Processing' has emerged as a separate independent field. Image Processing is being used in a number of disciplines. In the Medical Sciences, it is used to construct pseudo color images from computer aided tomography (CAT) or positron emission tomography (PET) scanners. Art, advertising and publishing people use pseudo colours in pursuit of more effective graphics. Structural engineers use Image Processing to examine weld X-rays to search for imperfections. Photographers use Image Processing for various enhancements which are difficult to achieve in a conventional dark room. (author)

  8. Power system transient stability analysis based on branch potential characteristics

    Science.gov (United States)

    Han, Huan; Wang, Zengping

    2017-09-01

    Branch potential function is proposed based on the power system network preserving model. The concept of thermodynamics-entropy, is introduced to describe spatial distribution characteristics of the branch potential energy. Branch potential energy was analysed in time and space domain., with transient stability index proposed accordingly. The larger disturbance energy line fault injected to grid is, the larger branch energy entropy will be, and the more energy accumulated on key branches is, the more prone to lose stability the system will be. Simulation results on IEEE system proved its feasibility.

  9. Pedicle Screw-Based Posterior Dynamic Stabilization: Literature Review

    Directory of Open Access Journals (Sweden)

    Dilip K. Sengupta

    2012-01-01

    Full Text Available Posterior dynamic stabilization (PDS indicates motion preservation devices that are aimed for surgical treatment of activity related mechanical low back pain. A large number of such devices have been introduced during the last 2 decades, without biomechanical design rationale, or clinical evidence of efficacy to address back pain. Implant failure is the commonest complication, which has resulted in withdrawal of some of the PDS devices from the market. In this paper the authors presented the current understanding of clinical instability of lumbar motions segment, proposed a classification, and described the clinical experience of the pedicle screw-based posterior dynamic stabilization devices.

  10. Penaeus vannamei protease stabilizing process of ZnS nanoparticles.

    Science.gov (United States)

    Razzaghi, Mozhgan; Homaei, Ahmad; Mosaddegh, Elaheh

    2018-01-31

    The protease enzyme purified from the Penaeus vannamei shrimp has unique properties, so improving the stability of this enzyme can improve their practical applications. In this study, ZnS nanoparticles, which have special properties for enzyme immobilization, were synthesized using a chemical precipitation method, and Penaeus vannamei protease was successfully immobilized on them. The size, structure, and morphology of the ZnS nanoparticles, and the immobilization of the protease were studied, using Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FT-IR) spectroscopy, UV-Vis spectroscopy and Dynamic Light Scattering (DLS) analysis. We show that the immobilized enzyme has improved functionality at high temperatures, extreme pH conditions (pH3 and 12), and during storage. Immobilization increased the optimum temperature range of the enzyme, but did not change the pH optimum, which remained at pH7. Immobilization of P. vannamei protease enzyme increased the K m and decreased k cat /K m . These results indicate that P. vannamei protease immobilized on ZnS nanoparticles, has improved properties due to its high stability and unique properties, can be used for biotechnology applications. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Species-specific traits plus stabilizing processes best explain coexistence in biodiverse fire-prone plant communities.

    Directory of Open Access Journals (Sweden)

    Jürgen Groeneveld

    Full Text Available Coexistence in fire-prone Mediterranean-type shrublands has been explored in the past using both neutral and niche-based models. However, distinct differences between plant functional types (PFTs, such as fire-killed vs resprouting responses to fire, and the relative similarity of species within a PFT, suggest that coexistence models might benefit from combining both neutral and niche-based (stabilizing approaches. We developed a multispecies metacommunity model where species are grouped into two PFTs (fire-killed vs resprouting to investigate the roles of neutral and stabilizing processes on species richness and rank-abundance distributions. Our results show that species richness can be maintained in two ways: i strictly neutral species within each PFT, or ii species within PFTs differing in key demographic properties, provided that additional stabilizing processes, such as negative density regulation, also operate. However, only simulations including stabilizing processes resulted in structurally realistic rank-abundance distributions over plausible time scales. This result underscores the importance of including both key species traits and stabilizing (niche processes in explaining species coexistence and community structure.

  12. On the stability of adaptation process in active noise control systems.

    Science.gov (United States)

    Ardekani, Iman Tabatabaei; Abdulla, Waleed H

    2011-01-01

    The stability analysis of the adaptation process, performed by the filtered-x least mean square algorithm on weights of active noise controllers, has not been fully investigated. The main contribution of this paper is conducting a theoretical stability analysis for this process without utilizing commonly used simplifying assumptions regarding the secondary electro-acoustic channel. The core of this analysis is based on the root locus theory. The general rules for constructing the root locus plot of the adaptation process are derived by obtaining root locus parameters, including start points, end points, asymptote lines, and breakaway points. The conducted analysis leads to the derivation of a general upper-bound for the adaptation step-size beyond which the mean weight vector of the active noise controller becomes unstable. Also, this analysis yields the optimum step-size for which the adaptive active noise controller has its fastest dynamic performance. The proposed upper-bound and optimum values apply to general secondary electro-acoustic channels, unlike the commonly used ones which apply to only pure delay channels. The results are found to agree very well with those obtained from numerical analyses and computer simulation experiments.

  13. Stabilization and PID tuning algorithms for second-order unstable processes with time-delays.

    Science.gov (United States)

    Seer, Qiu Han; Nandong, Jobrun

    2017-03-01

    Open-loop unstable systems with time-delays are often encountered in process industry, which are often more difficult to control than stable processes. In this paper, the stabilization by PID controller of second-order unstable processes, which can be represented as second-order deadtime with an unstable pole (SODUP) and second-order deadtime with two unstable poles (SODTUP), is performed via the necessary and sufficient criteria of Routh-Hurwitz stability analysis. The stability analysis provides improved understanding on the existence of a stabilizing range of each PID parameter. Three simple PID tuning algorithms are proposed to provide desired closed-loop performance-robustness within the stable regions of controller parameters obtained via the stability analysis. The proposed PID controllers show improved performance over those derived via some existing methods. Copyright © 2017. Published by Elsevier Ltd.

  14. Rice industrial processing worldwide and impact on macro- and micronutrient content, stability, and retention.

    Science.gov (United States)

    Atungulu, Griffiths G; Pan, Zhongli

    2014-09-01

    Various processing methods are used in the food industry worldwide to produce numerous rice products with desirable sensory qualities based on cultural and cooking preferences and nutritional considerations. The processes result in variable degrees of macro- and micronutrient content, stability, and retention, depending on rice variety and original nutritional quality. In this article, modern and traditional premilling, milling, and postmilling processing methods of different rice types are comprehensively reviewed. The implications of industrial rice processing methods, especially milling, as well as techniques for nutrient extraction, transfer, and enhancement, such as rice parboiling, sprouting, and fortification, for macro- and micronutrient content and consumer acceptance of the products, are documented. Socioeconomic constraints facing various aspects of rice processing methods are also discussed. This article reviews up-to-date research on rice industrial processing worldwide and aims to benefit engineers dealing with food processing, nutritionists and dieticians, food companies, education and research institutions, and quality-control and safety managers. © 2014 New York Academy of Sciences.

  15. Hillslope processes: Mass wasting, slope stability and erosion

    NARCIS (Netherlands)

    van Beek, R.; Cammeraat, E.; Andreu, V.; Mickovski, S.B.; Dorren, L.; Norris, J.E.; Stokes, A.; Mickovski, S.B.; Cammeraat, E.; van Beek, R.; Nicoll, B.C.; Achim, A.

    2008-01-01

    This chapter describes the dominant types of processes present on hillslopes where both gravity and running water are active. The impact of natural hillslope processes is important and is currently strongly influenced by human activity due to land use change and vegetation removal, and is becoming

  16. Dependence of the Stabilization of α-Alumina on the Spray Process

    Science.gov (United States)

    Stahr, Carl Christoph; Saaro, Sabine; Berger, Lutz-Michael; Dubský, Jiri; Neufuss, Karel; Herrmann, Mathias

    2007-12-01

    A phase change from α-alumina (corundum) in the feedstock powder to predominantly other alumina phases, such as γ-alumina in the coating normally takes place, as a result of the spray process. It is expected that the prevention of this phase transformation will significantly improve the mechanical, electrical, and other properties of thermally sprayed alumina coatings. The results regarding the possibility of stabilization of α-alumina through addition of chromia published in the literature are ambiguous. In this work, stabilization using different spray processes (water-stabilized plasma (WSP), gas-stabilized plasma (APS), and high-velocity oxy-fuel spray (HVOF)) was studied. Mechanical mixtures of alumina and chromia were used, as were prealloyed powders consisting of solid solutions. The investigations focused on mechanical mixtures with both APS and WSP and on prealloyed powders with WSP. The coatings were studied by x-ray diffraction, including Rietveld analysis, and analysis of the lattice parameters. Microstructures were investigated by optical microscopy using metallographic cross-sections. It was shown that in the case of the mechanically mixed powders, the stabilization predominantly depends on the applied spray process. The stabilization of the α phase by use of the WSP process starting from mechanical mixtures was confirmed. It appears that stabilization exhibits a complex dependence on the spray process, the process parameters (in particular the thermal history), the nature of the powder (mechanically mixed or prealloyed), and the chromia content.

  17. Actively-stabilized photomultiplier tube base for vacuum operation

    International Nuclear Information System (INIS)

    Bryan, M.A; Morris, C.L.; Idzorek, G.C.

    1992-01-01

    An actively stabilized photomultiplier tube (PMT) base design for an Amperex XP-2262B PMT is described. Positive-negative-positive transistors are used as low-impedance current sources to maintain constant voltages on the last three dynodes. This technique results in a highly stable, low-power tube base ideal for use with low-duty-factor beams, such as those found at the Clinton P. Anderson Meson Physics Facility. Furthermore, because of the low power usage of this large design, these bases can be sealed in a heat-conductive, electrically insulating material and used in a vacuum

  18. Design of an adaptive neural network based power system stabilizer.

    Science.gov (United States)

    Liu, Wenxin; Venayagamoorthy, Ganesh K; Wunsch, Donald C

    2003-01-01

    Power system stabilizers (PSS) are used to generate supplementary control signals for the excitation system in order to damp the low frequency power system oscillations. To overcome the drawbacks of conventional PSS (CPSS), numerous techniques have been proposed in the literature. Based on the analysis of existing techniques, this paper presents an indirect adaptive neural network based power system stabilizer (IDNC) design. The proposed IDNC consists of a neuro-controller, which is used to generate a supplementary control signal to the excitation system, and a neuro-identifier, which is used to model the dynamics of the power system and to adapt the neuro-controller parameters. The proposed method has the features of a simple structure, adaptivity and fast response. The proposed IDNC is evaluated on a single machine infinite bus power system under different operating conditions and disturbances to demonstrate its effectiveness and robustness.

  19. A digital frequency stabilization system of external cavity diode laser based on LabVIEW FPGA

    Science.gov (United States)

    Liu, Zhuohuan; Hu, Zhaohui; Qi, Lu; Wang, Tao

    2015-10-01

    Frequency stabilization for external cavity diode laser has played an important role in physics research. Many laser frequency locking solutions have been proposed by researchers. Traditionally, the locking process was accomplished by analog system, which has fast feedback control response speed. However, analog system is susceptible to the effects of environment. In order to improve the automation level and reliability of the frequency stabilization system, we take a grating-feedback external cavity diode laser as the laser source and set up a digital frequency stabilization system based on National Instrument's FPGA (NI FPGA). The system consists of a saturated absorption frequency stabilization of beam path, a differential photoelectric detector, a NI FPGA board and a host computer. Many functions, such as piezoelectric transducer (PZT) sweeping, atomic saturation absorption signal acquisition, signal peak identification, error signal obtaining and laser PZT voltage feedback controlling, are totally completed by LabVIEW FPGA program. Compared with the analog system, the system built by the logic gate circuits, performs stable and reliable. User interface programmed by LabVIEW is friendly. Besides, benefited from the characteristics of reconfiguration, the LabVIEW program is good at transplanting in other NI FPGA boards. Most of all, the system periodically checks the error signal. Once the abnormal error signal is detected, FPGA will restart frequency stabilization process without manual control. Through detecting the fluctuation of error signal of the atomic saturation absorption spectrum line in the frequency locking state, we can infer that the laser frequency stability can reach 1MHz.

  20. "Psychological Boarding" and Community-Based Behavioral Health Crisis Stabilization.

    Science.gov (United States)

    Mukherjee, Dhrubodhi; Saxon, Verletta

    2018-01-27

    This exploratory paper presents a case study where a community based mental health organization forging a partnership with a local hospital system to establish a crisis stabilization unit (CSU) to address behavioral health emergency care. The study takes a mixed methods case study approach to address two research questions; (a) did this approach reduce the overall length of stay in the hospital emergency departments? (b) What challenges did the taskforce face in implementing this CSU model? The paper shares recommendation from the findings.

  1. Passivity Based Stabilization of Non-minimum Phase Nonlinear Systems

    Czech Academy of Sciences Publication Activity Database

    Travieso-Torres, J.C.; Duarte-Mermoud, M.A.; Zagalak, Petr

    2009-01-01

    Roč. 45, č. 3 (2009), s. 417-426 ISSN 0023-5954 R&D Projects: GA ČR(CZ) GA102/07/1596 Institutional research plan: CEZ:AV0Z10750506 Keywords : nonlinear systems * stabilisation * passivity * state feedback Subject RIV: BC - Control Systems Theory Impact factor: 0.445, year: 2009 http://library.utia.cas.cz/separaty/2009/AS/zagalak-passivity based stabilization of non-minimum phase nonlinear systems.pdf

  2. Low temperature stabilization process for production of carbon fiber having structural order

    Science.gov (United States)

    Rios, Orlando; McGuire, Michael Alan; More, Karren Leslie; Tenhaeff, Wyatt Evan; Menchhofer, Paul A.; Paulauskas, Felix Leonard

    2017-08-15

    A method for producing a carbon fiber, the method comprising: (i) subjecting a continuous carbon fiber precursor having a polymeric matrix in which strength-enhancing particles are incorporated to a stabilization process during which the carbon fiber precursor is heated to within a temperature range ranging from the glass transition temperature to no less than 20.degree. C. below the glass transition temperature of the polymeric matrix, wherein the maximum temperature employed in the stabilization process is below 400.degree. C., for a processing time within said temperature range of at least 1 hour in the presence of oxygen and in the presence of a magnetic field of at least 1 Tesla, while said carbon fiber precursor is held under an applied axial tension; and (ii) subjecting the stabilized carbon fiber precursor, following step (i), to a carbonization process. The stabilized carbon fiber precursor, resulting carbon fiber, and articles made thereof are also described.

  3. The Colloidal Stabilization of Quantum Dots: Towards Manufacturable, Efficient Solution-Processed Solar Cells

    Science.gov (United States)

    Rollny, Lisa

    Understanding colloidal stabilization can influence the design of optoelectronic devices and enable improvements to their performance and stability. For photovoltaics, important characteristics of the active layer material are high conductivity along with a minimum of recombination centers. In order to capitalize on the benefits of solution-processed materials, it is important to minimize the number of processing steps: ideally, to achieve a low-cost solution, materials would be deposited using a single process step compatible with roll-to-roll manufacturing. Prior to this work, the highest-performing colloidal quantum dots (CQD) solar cells have relied on several deposition steps that are repeated in a layer-by-layer (LBL) fashion. The purpose of these process steps has been to remove the long insulating ligands used in synthesis and replace them with short ligands that allow electrical conduction. The large number of steps combined, typically implemented via spin coating, leads to inefficient materials utilization and fails to show a path to a manufacturable solution. In this work, the first CQD solar cells were designed, built, and characterized combining state-of-art performance with scalable manufacture. Firstly, I report the first automated CQD synthesis to result in CQDs that form high-performance CQD solar cells. I analyze the CQD synthesis and by separating it into two phases---nucleation and growth phase---my insights are used to create higher-quality CQDs exhibiting enhanced monodispersity. I then proceed to develop a CQD ink: a CQD solution ready for direct deposition to form a semiconducting film exhibiting low trap state density. In early trials the CQD ink showed only limited power conversion efficiencies of 2%. I designed a new ink strategy, which I term cleavable hemiketal ligands. This novel two-component ligand strategy enables the combination of colloidal stabilization (via this longer two-component ligand) and cleavability (enabling excellent

  4. An offset tone based gain stabilization technique for mixed-signal RF measurement systems

    International Nuclear Information System (INIS)

    Joshi, Gopal; Motiwala, Paresh D.; Randale, G.D.; Singh, Pitamber; Agarwal, Vivek; Kumar, Girish

    2015-01-01

    This paper describes a gain stabilization technique for a RF signal measurement system. A sinusoidal signal of known amplitude, phase and close enough in frequency is added to the main, to be measured RF signal at the input of the analog section. The system stabilizes this offset tone in the digital domain, as it is sampled at the output of the analog section. This process generates a correction factor needed to stabilize the magnitude of the gain of the analog section for the main RF signal. With the help of a simple calibration procedure, the absolute amplitude of the main RF signal can be measured. The technique is especially suited for a system that processes signals around a single frequency, employs direct signal conversion into the digital domain, and processes subsequent steps in an FPGA. The inherent parallel signal processing in an FPGA-based implementation allows a real time stabilization of the gain. The effectiveness of the technique is derived from the fact, that the gain stabilization stamped to the main RF signal measurement branch requires only a few components in the system to be inherently stable. A test setup, along with experimental results is presented from the field of RF instrumentation for particle accelerators. Due to the availability of a phase synchronized RF reference signal in these systems, the measured phase difference between the main RF and the RF reference is also stabilized using this technique. A scheme of the signal processing is presented, where a moving average filter has been used to filter out not only the unwanted frequencies, but also to separate the main RF signal from the offset tone signal. This is achieved by a suitable choice of sampling and offset tone frequencies. The presented signal processing scheme is suitable to a variety of RF measurement applications

  5. An offset tone based gain stabilization technique for mixed-signal RF measurement systems

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Gopal, E-mail: gjos@barc.gov.in [BARC, Mumbai 400085 (India); Motiwala, Paresh D.; Randale, G.D.; Singh, Pitamber [BARC, Mumbai 400085 (India); Agarwal, Vivek; Kumar, Girish [IIT Bombay, Powai, Mumbai 400076 (India)

    2015-09-21

    This paper describes a gain stabilization technique for a RF signal measurement system. A sinusoidal signal of known amplitude, phase and close enough in frequency is added to the main, to be measured RF signal at the input of the analog section. The system stabilizes this offset tone in the digital domain, as it is sampled at the output of the analog section. This process generates a correction factor needed to stabilize the magnitude of the gain of the analog section for the main RF signal. With the help of a simple calibration procedure, the absolute amplitude of the main RF signal can be measured. The technique is especially suited for a system that processes signals around a single frequency, employs direct signal conversion into the digital domain, and processes subsequent steps in an FPGA. The inherent parallel signal processing in an FPGA-based implementation allows a real time stabilization of the gain. The effectiveness of the technique is derived from the fact, that the gain stabilization stamped to the main RF signal measurement branch requires only a few components in the system to be inherently stable. A test setup, along with experimental results is presented from the field of RF instrumentation for particle accelerators. Due to the availability of a phase synchronized RF reference signal in these systems, the measured phase difference between the main RF and the RF reference is also stabilized using this technique. A scheme of the signal processing is presented, where a moving average filter has been used to filter out not only the unwanted frequencies, but also to separate the main RF signal from the offset tone signal. This is achieved by a suitable choice of sampling and offset tone frequencies. The presented signal processing scheme is suitable to a variety of RF measurement applications.

  6. Effects of variable sticking coefficients on the stability of reactive sputtering process

    International Nuclear Information System (INIS)

    Li Chuan; Hsieh Janghsing

    2004-01-01

    In reactive sputtering, the introduction of a reactive gas can lead to a hysteresis transition from metal to compounds in both the target and substrate. The hysteresis transition is characterized by a sudden change in partial pressure, sputtering rate, fraction of compound formation, etc. Therefore, stability is an important issue in the process control. In this paper, a mathematical model with variable sticking coefficients based on surface kinetics is used to study the stability of the process. The variable sticking coefficient represents different mechanisms for surface reactions from the Langmuir to precursor type. In order to facilitate the analysis, several nondimensional parameters are identified and used for formulation. Results show that an unsteady system converges to a steady state relatively fast at low inflow rates. With an eigenvalue analysis, the range of positive eigenvalues is consistent with the presence of a hysteresis loop. It is also found that when the chemical reaction on the substrate is moderate, a higher sputter yield of the compound leads to a more stable steady state at lower inflow rates. Regarding the sticking mechanism, for the type of precursors with the parameter k < 1, the compound is easier to form and saturate on the surface due to the higher default sticking coefficient and the lower operating conditions for the hysteresis transition

  7. A tâtonnement process with fading memory, stabilization and optimal speed of convergence

    International Nuclear Information System (INIS)

    Cavalli, Fausto; Naimzada, Ahmad

    2015-01-01

    The purpose of this work is to provide a way to improve stability and convergence rate of a price adjustment mechanism that converges to a Walrasian equilibrium. We focus on a discrete tâtonnement based on a two-agent, two-good exchange economy, and we introduce memory, assuming that the auctioneer adjusts prices not only using the current excess demand, but also making use of the past excess demand functions. In particular, we study the effect of computing a weighted average of the current and the previous excess demands (finite two level memory) and of all the previous excess demands (infinite memory). We show that suitable weights’ distributions have a stabilizing effect, so that the resulting price adjustment process converge toward the competitive equilibrium in a wider range of situations than the process without memory. Finally, we investigate the convergence speed toward the equilibrium of the proposed mechanisms. In particular, we show that using infinite memory with fading weights approaches the competitive equilibrium faster than with a distribution of quasi-uniform weights.

  8. Performance and stability of mask process correction for EBM-7000

    Science.gov (United States)

    Saito, Yasuko; Chen, George; Wang, Jen-Shiang; Bai, Shufeng; Howell, Rafael; Li, Jiangwei; Tao, Jun; VanDenBroeke, Doug; Wiley, Jim; Takigawa, Tadahiro; Ohnishi, Takayuki; Kamikubo, Takashi; Hara, Shigehiro; Anze, Hirohito; Hattori, Yoshiaki; Tamamushi, Shuichi

    2010-05-01

    In order to support complex optical masks today and EUV masks in the near future, it is critical to correct mask patterning errors with a magnitude of up to 20nm over a range of 2000nm at mask scale caused by short range mask process proximity effects. A new mask process correction technology, MPC+, has been developed to achieve the target requirements for the next generation node. In this paper, the accuracy and throughput performance of MPC+ technology is evaluated using the most advanced mask writing tool, the EBM-70001), and high quality mask metrology . The accuracy of MPC+ is achieved by using a new comprehensive mask model. The results of through-pitch and through-linewidth linearity curves and error statistics for multiple pattern layouts (including both 1D and 2D patterns) are demonstrated and show post-correction accuracy of 2.34nm 3σ for through-pitch/through-linewidth linearity. Implementing faster mask model simulation and more efficient correction recipes; full mask area (100cm2) processing run time is less than 7 hours for 32nm half-pitch technology node. From these results, it can be concluded that MPC+ with its higher precision and speed is a practical technology for the 32nm node and future technology generations, including EUV, when used with advance mask writing processes like the EBM-7000.

  9. Aggregative stability of fungicidal nanomodifier based on zinc hydrosilicates

    Science.gov (United States)

    Grishina, Anna; Korolev, Evgeniy

    2018-03-01

    Currently, there is a strong need of high performance multi functional materials in high-rise construction. Obviously, such materials should be characterized by high strength; but for interior rooms biosafety is important as well. The promising direction to obtain both high strength and maintain biosafety in buildings and structures is to manage the structure of mineral binders by means of fungicidal nanomodifier based on zinc hydrosilicates. In the present work the aggregative stability of colloidal solutions of zinc hydrosilicates after one year of storage was studied. It has been established that the concentration of iron (III) hydroxide used to prepare the precursor of zinc hydrosilicates has a significant effect on the long-term aggregative stability: as the concentration of iron (III) hydroxide increases, the resistance of the fungicidal nanomodifier increases. It was found that, despite the minimal concentration of nano-sized zinc hydrosilicates (0.028%), the colloidal solution possesses a low long-term aggregative stability; while in the initial period (not less than 14 days) the colloidal solution of the nanomodifier is aggregatively stable. It is shown that when the ratio in the colloidal solution of the amount of the substance CH3COOH / SiO2 = 0.43 is reached, an increase in the polymerization rate is observed, which is the main cause of low aggregative stability. Colloidal solutions containing zinc hydrosilicates synthesized at a concentration of iron (III) hydroxide used to produce a precursor equal to 0.7% have a long-term aggregative stability and do not significantly change the reduced particle. Such compositions are to be expediently used for the nanomodifying of building composites in order to control their structure formation and to create conditions that impede the development of various mycelial fungi.

  10. Effect of the method of processing on quality and oxidative stability ...

    African Journals Online (AJOL)

    In this study four samn samples prepared from cow milk using two processing methods (traditional T1, T2 and factory processed T3, T4) were investigated for their physico-chemical properties, fatty acids composition, oxidative stability and sensory properties. The traditionally processed samples showed a significance ...

  11. Enhanced Stability of Retained Austenite by Quenching and Double Partitioning Process

    Science.gov (United States)

    Hou, Z. R.; Zhao, X. M.

    2017-12-01

    In the present study, a novel quenching and double partitioning (Q&DP) process is proposed. The quenching and partitioning (Q&P) process was accompanied by a second partitioning process, which led to the enhanced stability of retained austenite. The chemical composition of the investigated steel was 0.24C-1.9Mn-1.85Si, without an excess addition of alloying elements. This process aims to enhance the stability of retained austenite by controlling martensitic transformation and carbon partitioning. By applying this process, the uniform and total elongation is increased, without obvious reduction in ultimate tensile strength. An optimum combination of strength and ductility (ultimate tensile strength: 1304MPa; total elongation: 23%) was achieved by quenching to 65°C and subsequent second partitioning treatment, after the first quenching to 300°C and partitioning process. The enhanced mechanical properties were attributed to the increased amount of stabilized film-like austenite.

  12. Vibration and Stability of 3000-hp, Titanium Chemical Process Blower

    Directory of Open Access Journals (Sweden)

    Les Gutzwiller

    2003-01-01

    Full Text Available This 74-in-diameter blower had an overhung rotor design of titanium construction, operating at 50 pounds per square inch gauge in a critical chemical plant process. The shaft was supported by oil-film bearings and was directdriven by a 3000-hp electric motor through a metal disk type of coupling. The operating speed was 1780 rpm. The blower shaft and motor shaft motion was monitored by Bently Nevada proximity probes and a Model 3100 monitoring system.

  13. A comprehensive gaze stabilization controller based on cerebellar internal models

    DEFF Research Database (Denmark)

    Vannucci, Lorenzo; Falotico, Egidio; Tolu, Silvia

    2017-01-01

    based on the coordination of VCR and VOR and OKR. The model, inspired by neuroscientific cerebellar theories, is provided with learning and adaptation capabilities based on internal models. We present the results for the gaze stabilization model on three sets of experiments conducted on the SABIAN robot...... and on the iCub simulator, validating the robustness of the proposed control method. The first set of experiments focused on the controller response to a set of disturbance frequencies along the vertical plane. The second shows the performances of the system under three-dimensional disturbances. The last set...

  14. Adaptive Central Force Optimization Algorithm Based on the Stability Analysis

    Directory of Open Access Journals (Sweden)

    Weiyi Qian

    2015-01-01

    Full Text Available In order to enhance the convergence capability of the central force optimization (CFO algorithm, an adaptive central force optimization (ACFO algorithm is presented by introducing an adaptive weight and defining an adaptive gravitational constant. The adaptive weight and gravitational constant are selected based on the stability theory of discrete time-varying dynamic systems. The convergence capability of ACFO algorithm is compared with the other improved CFO algorithm and evolutionary-based algorithm using 23 unimodal and multimodal benchmark functions. Experiments results show that ACFO substantially enhances the performance of CFO in terms of global optimality and solution accuracy.

  15. Structural and Mechanical Characterization of Sustainable Composites Based on Recycled and Stabilized Fly Ash

    Directory of Open Access Journals (Sweden)

    Stefano Besco

    2014-08-01

    Full Text Available This paper reports the results on the use of an innovative inert, based on stabilized fly ash from municipal solid waste incineration as a filler for polypropylene. The starting material, which contains large quantities of leachable Pb and Zn, was stabilized by means of an innovative process using rice husk ash as a waste silica source, together with other fly ashes, such as coal fly ash and flue gas desulfurization residues. The use of all waste materials to obtain a new filler makes the proposed technology extremely sustainable and competitive. The new composites, obtained by using the stabilized material as a filler for polypropylene, were characterized and their mechanical properties were also investigated. A comparison with a traditional polypropylene and calcium carbonate based compound was also done. This research activity was realized in the frame of the COSMOS-RICE project, financed by the EU Commission.

  16. Maltodextrin-incorporated-vacuum-dried honey powder: processing and stability

    OpenAIRE

    Nurhadi, Bambang

    2016-01-01

    Honey is rich in sugar content and dominated by fructose and glucose that make honey prone to crystallize during storage. Due to honey composition, the anhydrous glass transition temperature of honey is very low that makes honey difficult to dry alone and drying aid or filler is needed to dry honey. Maltodextrin is a common drying aid material used in drying of sugar-rich food. The present study aims to study the processing of honey powder by vacuum drying method and the impact of drying proc...

  17. Stabilization

    Directory of Open Access Journals (Sweden)

    Muhammad H. Al-Malack

    2016-07-01

    Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.

  18. ABOUT THE METHODS USED IN PROCESS OF MANAGEMENT OF SOCIAL STABILITY OF THE ENTERPRISE OF TRANSPORT BUSINESS

    Directory of Open Access Journals (Sweden)

    Tabachnikova E. V.

    2016-12-01

    Full Text Available Implementation of the basic principle of the concept of the sustainable development consisting in need of ensuring cost efficiency, social justice and an ecological safety is one of modern requirements to activities of the enterprise. According to the designated purposes within general stability were allocated functional, financial and economic, social and ecological stability of the enterprise. Process of management of stability assumes the choice and adaptation of the corresponding methods and technologies. For the purpose of development of methodology of management of stability of the enterprise the approach to assessment of effectiveness of management based on use of indicators of organizational and labor capacities of the enterprise is offered. A number of offers was made on the basis of results of the researches conducted by the author in the motor transportation enterprises of St. Petersburg in 2014. Methodical approaches to assessment of the indicators characterizing social stability of the entity are given in article. The role of methods of management of organizational changes, in particular, of methods of overcoming resistance of personnel, in the course of ensuring social stability of the enterprise is designated.

  19. Applications of FBG-based sensors to ground stability monitoring

    Directory of Open Access Journals (Sweden)

    An-Bin Huang

    2016-08-01

    Full Text Available Over the past few decades, many optical fiber sensing techniques have been developed. Among these available sensing methods, optical fiber Bragg grating (FBG is probably the most popular one. With its unique capabilities, FBG-based geotechnical sensors can be used as a sensor array for distributive (profile measurements, deployed under water (submersible, for localized high resolution and/or differential measurements. The authors have developed a series of FBG-based transducers that include inclination, linear displacement and gauge/differential pore pressure sensors. Techniques that involve the field deployment of FBG inclination, extension and pore-pressure sensor arrays for automated slope stability and ground subsidence monitoring have been developed. The paper provides a background of FBG and the design concepts behind the FBG-based field monitoring sensors. Cases of field monitoring using the FBG sensor arrays are presented, and their practical implications are discussed.

  20. A gait stability investigation into FES-assisted paraplegic walking based on the walker tipping index

    Science.gov (United States)

    Ming, Dong; Bai, Yanru; Liu, Xiuyun; Qi, Hongzhi; Cheng, Longlong; Wan, Baikun; Hu, Yong; Wong, Yatwa; Luk, Keith D. K.; Leong, John C. Y.

    2009-12-01

    The gait outcome measures used in clinical trials of paraplegic locomotor training determine the effectiveness of improved walking function assisted by the functional electrical stimulation (FES) system. Focused on kinematic, kinetic or physiological changes of paraplegic patients, traditional methods cannot quantify the walking stability or identify the unstable factors of gait in real time. Up until now, the published studies on dynamic gait stability for the effective use of FES have been limited. In this paper, the walker tipping index (WTI) was used to analyze and process gait stability in FES-assisted paraplegic walking. The main instrument was a specialized walker dynamometer system based on a multi-channel strain-gauge bridge network fixed on the frame of the walker. This system collected force information for the handle reaction vector between the patient's upper extremities and the walker during the walking process; the information was then converted into walker tipping index data, which is an evaluation indicator of the patient's walking stability. To demonstrate the potential usefulness of WTI in gait analysis, a preliminary clinical trial was conducted with seven paraplegic patients who were undergoing FES-assisted walking training and seven normal control subjects. The gait stability levels were quantified for these patients under different stimulation patterns and controls under normal walking with knee-immobilization through WTI analysis. The results showed that the walking stability in the FES-assisted paraplegic group was worse than that in the control subject group, with the primary concern being in the anterior-posterior plane. This new technique is practical for distinguishing useful gait information from the viewpoint of stability, and may be further applied in FES-assisted paraplegic walking rehabilitation.

  1. Sparse Reconstruction of Regional Gravity Signal Based on Stabilized Orthogonal Matching Pursuit (SOMP)

    Science.gov (United States)

    Saadat, S. A.; Safari, A.; Needell, D.

    2016-06-01

    The main role of gravity field recovery is the study of dynamic processes in the interior of the Earth especially in exploration geophysics. In this paper, the Stabilized Orthogonal Matching Pursuit (SOMP) algorithm is introduced for sparse reconstruction of regional gravity signals of the Earth. In practical applications, ill-posed problems may be encountered regarding unknown parameters that are sensitive to the data perturbations. Therefore, an appropriate regularization method needs to be applied to find a stabilized solution. The SOMP algorithm aims to regularize the norm of the solution vector, while also minimizing the norm of the corresponding residual vector. In this procedure, a convergence point of the algorithm that specifies optimal sparsity-level of the problem is determined. The results show that the SOMP algorithm finds the stabilized solution for the ill-posed problem at the optimal sparsity-level, improving upon existing sparsity based approaches.

  2. Stability Control of Propeller Autonomous Underwater Vehicle Based on Combined Sections Method

    Directory of Open Access Journals (Sweden)

    Qi Duo

    2015-09-01

    Full Text Available Learning from the motion principle of quadrotor, a symmetric propeller AUV, which has small size and low velocity is designed. Compared with the AUV equipped with rudders, it has better maneuverability and manipulation at low velocity. According to the Newton-Euler method, the 6 DOF kinematic model and dynamic model of the propeller AUV are established. A stability controller that consists of 3 different PID controllers is designed. It makes the depth and attitude angle as trigger conditions, and the relevant controller is chosen in different moving process. The simulation experiments simulate ideal motion state and disturbed motion state, and experiments results show that the stability controller based on combined sections method can make the best of mature technology of PID, and meet the control requirements in different stages. It has a higher respond speed and accuracy, improving the stability of the propeller AUV under the disturbance of complex ocean currents.

  3. Stability of plant virus-based nanocarriers in gastrointestinal fluids.

    Science.gov (United States)

    Berardi, Alberto; Evans, David J; Baldelli Bombelli, Francesca; Lomonossoff, George P

    2018-01-25

    Cowpea mosaic virus (CPMV) is a plant virus which is being extensively investigated as a drug delivery and vaccine nanocarrier for parenteral administration. However, to date little is known about the suitability of plant-based nanocarriers for oral delivery. In this study, the colloidal (i.e. aggregation), physical (i.e. denaturation) and chemical (i.e. digestion of the polypeptides) stability of CPMV and its empty virus-like particles (eVLPs) in conditions resembling the gastrointestinal fluids were evaluated. The nanoparticles were incubated in various simulated gastric and intestinal fluids and in pig gastric and intestinal fluids. CPMV and eVLPs had similar stabilities. In simulated gastric media, they were stable at pH ≥ 2.5. At lower pH destabilisation of the particle structure occurred, which, in turn, rendered the polypeptides extremely sensitive to pepsin digestion. However, both CPMV and eVLPs were stable in simulated intestinal fluids, in pig gastric fluids and in pig intestinal fluids. Thus CPMV, despite being a protein-based nanoparticle, was much more resistant to the harsh GI conditions than soluble proteins. Remarkably, both CPMV and eVLPs incubated in pig gastric and intestinal fluids were not subject to protein adsorption, with no formation of a detectable protein corona. The lack of a protein corona on CPMV and eVLP surfaces in GI fluids would imply that, if orally administered, these nanoparticles could maintain their native surface characteristics; thus, their biological interactions would remain predictable and unchanged. In summary, CPMV and eVLPs can be considered promising nanocarriers for applications requiring oral delivery, given their chemical, physical and colloidal stability and lack of protein adsorption from the environment in most of the tested conditions.

  4. Synthesis, Structure, Stability and Redispersion of Gold-based Nanoparticles

    Science.gov (United States)

    Tiruvalam, Ram Chandra

    Nanoscale gold has been shown to possess an intriguing combination of unexpected optical, photochemical and catalytic properties. The ability to control the size, shape, morphology, composition and dispersion of gold-based nanostructures is key to optimizing their performance for nanotechnology applications. The advanced electron microscopy studies described in this thesis analyze three important aspects of gold and gold-palladium alloy nanoparticles: namely, (i) the ability to synthesize gold nanoparticles of controlled size and shape in an aqueous medium; (ii) the colloidal preparation of designer gold-palladium alloys for selective oxidation catalysis; and (iii) the ability to disperse gold as finely and homogeneously as possible on a metal oxide or carbon support. The ability to exploit the nanoscale properties of gold for various engineering applications often depends on our ability to control size and shape of the nanoscale entity by careful manipulation of the synthesis parameters. We have explored an aqueous based synthesis route, using oleylamine as both a reductant and surfactant, for preparing gold nanostructures. By systematically varying synthesis parameters such as oleylamine concentration, reaction temperature, and aging time it is possible to identify processing regimens that generate Au nanostructures having either pseudo-spherical, faceted polyhedral, nanostar or wire shaped morphologies. Furthermore, by quenching the reaction partway through it is possible to create a class of metastable Au-containing structures such as nanocubes, nanoboxes and nanowires. Possible formation mechanisms for these gold based nano-objects are discussed. There is a growing interest in using supported bimetallic AuPd alloy nanoparticles for selective oxidation reactions. In this study, a systematic series of size controlled AuPd bimetallic particles have been prepared by colloidal synthesis methods. Particles having random alloy structures, as well as `designer

  5. A MARTe based simulator for the JET Vertical Stabilization system

    Energy Technology Data Exchange (ETDEWEB)

    Bellizio, Teresa, E-mail: teresa.bellizio@unina.it [Associazione EURATOM-ENEA-CREATE, University di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); De Tommasi, Gianmaria; Risoli, Nicola; Albanese, Raffaele [Associazione EURATOM-ENEA-CREATE, University di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Neto, Andre [Associacao EURATOM/IST, Inst. de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior, Tecnico, P-1049-001 Lisboa (Portugal)

    2011-10-15

    Validation by means of simulation is a crucial step when developing real-time control systems. Modeling and simulation are an essential tool since the early design phase, when the control algorithms are designed and tested. This phase is commonly carried out in off-line environments such as Matlab and Simulink. A MARTe-based simulator has been recently developed to validate the new JET Vertical Stabilization (VS) system. MARTe is the multi-thread framework used at JET to deploy hard real-time control systems. This paper presents the software architecture of the MARTe-based simulator and it shows how this tool has been effectively used to evaluate the effects of Edge Localized Modes (ELMs) on the VS system. By using the simulator it is possible to analyze different plasma configurations, extrapolating the limit of the new vertical amplifier in terms of the energy of the largest rejectable ELM.

  6. Oxidase-based biocatalytic processes

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Woodley, John; Krühne, Ulrich

    limitations to the reaction system prior toexperimentation. Such an analysis presents the opportunity to direct experimental work and therefore reduce the time and effort spent on process development, by eliminating unfeasible routes. The example chosen for the development of the methodology was a specific......Biocatalytic processes are gaining significant focus in frontiers where they offer unique advantages(selectivity and mild operating conditions) over chemical catalysts. It is therefore not surprising that therehave been many industrial biocatalytic processes implemented.Despite past successes......, the implementation of a new biocatalytic process still presents some challenges (demands placed on the biocatalyst) in terms of the requirements to make a viable industrial process. Inorder for a biocatalytic process to be economically successful, it is necessary that certain a set of targetmetrics (product titre...

  7. Developing industries in cooperative interaction: equilibrium and stability in processes with lag

    Directory of Open Access Journals (Sweden)

    Aleksandr Kirjanen

    2017-11-01

    Full Text Available A mathematical model of dynamic interaction between mining and processing industries is formalized and studied in the paper. The process of interaction is described by a system of two delay dierential equations. The criterion for asymptotic stability of nontrivial equilibrium point is obtained when both industries co-work steadily. The problem is reduced to nding stability criterion for quasi-polynomial of second order. Time intervals between deliveries of raw materials which make it possible to preserve stable interaction between the two industries are found.

  8. Topical gel formulation and stability assessment of platelet lysate based on turbidimetric method

    Directory of Open Access Journals (Sweden)

    Soliman Mohammadi Samani

    2015-06-01

    Full Text Available Platelet-rich growth factors have attracted attentions of scientists and clinical practitioners who are involved in wound healing and regenerative medicine extensively, according to their unprecedented potential of promoting and catalyzing healing process. Platelet-rich growth factors are cost-benefit, available and more stable than recombinant human growth factors. These appealing characteristics have converted PRGF to one of the popular candidates for treatment of variety of wounds. According to these valuable properties, we decided to formulate and assess the effect of different excipients on the stability of such valuable protein based formulations. Different excipients have been chosen according to their effective ness on the stability of proteins and their application in other similar formulations. The stabilizing effect of excipients was evaluated by measuring heat-induced aggregation of growth factors by turbidimetric assay. Glycerol, glycine and dextrose were chosen as stabilizing excipients for these formulations. The results show that dextrose has more stabilizing effect on prevention of heat induced aggregation of the platelet lysate growth factors than glycerol and glycine. All of the formulations also contained antioxidant, chelating agents, preservative and carbopol934 in order to form appropriate gel.

  9. Chemical stability, thermal behavior, and shelf life assessment of extruded modified double-base propellants

    Directory of Open Access Journals (Sweden)

    Sherif Elbasuney

    2018-02-01

    Full Text Available Double base propellant suffers from lack of chemical stability; this could result in self ignition during storing. Modified double base (MDB propellant based on stoichiometric binary mixture of oxidizer-metal fuel (Ammonium perchlorate/Aluminum, and energetic nitramines (HMX offered enhanced thrust as well as combustion characteristics. This study is devoted to evaluate the impact of such energetic additives on thermal behavior, chemical stability, and shelf life. Extruded MDB formulations were manufactured by extrusion process. Artificial aging at 80 °C for 28 days was conducted. Shelf life assessment was performed using Van't Hoff's equation. Quantification of evolved NOx gases with aging time was performed using quantitative stability tests. MDB formulation based on HMX demonstrated extended service life of 16 years compared with (AP/Al-MDB which demonstrated 9 years. This finding was ascribed to the reactivity of AP with nitroglycerin with the formation of perchloric acid. Thermal behavior of aged MDB, exhibited an increase in heat released with time; this was ascribed to the auto-catalytic thermal degradation during artificial aging. The increase in released heat by 31% was found to be equivalent to evolved NOx gases of 6.2 cm3/5 g and 2.5 cm3/1 g for Bergmann-Junk test, and Vacuum stability test respectively. This manuscript shaded the light on a novel approach to quantify evolved NOx gases to heat released with aging time. MDB based on HMX offered balanced ballistic performance, chemical stability, and service life.

  10. Wavelength-stabilization-based photoacoustic spectroscopy for methane detection

    Science.gov (United States)

    Wang, Qiang; Wang, Zhen; Ren, Wei

    2017-06-01

    A compact and portable photoacoustic gas sensor was developed for sensitive methane (CH4) detection at 1.6 µm using a software-based wavelength stabilization scheme. A transmission-type photoacoustic cell was connected in series with a reference gas cell to measure the photoacoustic signal and the reference gas absorption for wavelength stabilization simultaneously. The central wavelength of the diode laser was locked to the target CH4 line with a fluctuation of less than 10.6 MHz using a digital proportional-integral-derivative controller. The CH4 sensor was designed to be insensitive to the incoherent external acoustic noise by the cumulative average of the demodulated photoacoustic signal by a digital lock-in amplifier. With an incident laser power of 6 mW, our CH4 sensor achieved a minimum detection limit of 11.5 ppm at 10 s response time and an excellent linearity (R 2  =  0.9999) in the concentration range of 400-6300 ppm.

  11. Tuning of tool dynamics for increased stability of parallel (simultaneous) turning processes

    Science.gov (United States)

    Ozturk, E.; Comak, A.; Budak, E.

    2016-01-01

    Parallel (simultaneous) turning operations make use of more than one cutting tool acting on a common workpiece offering potential for higher productivity. However, dynamic interaction between the tools and workpiece and resulting chatter vibrations may create quality problems on machined surfaces. In order to determine chatter free cutting process parameters, stability models can be employed. In this paper, stability of parallel turning processes is formulated in frequency and time domain for two different parallel turning cases. Predictions of frequency and time domain methods demonstrated reasonable agreement with each other. In addition, the predicted stability limits are also verified experimentally. Simulation and experimental results show multi regional stability diagrams which can be used to select most favorable set of process parameters for higher stable material removal rates. In addition to parameter selection, developed models can be used to determine the best natural frequency ratio of tools resulting in the highest stable depth of cuts. It is concluded that the most stable operations are obtained when natural frequency of the tools are slightly off each other and worst stability occurs when the natural frequency of the tools are exactly the same.

  12. Evaluation of the Magnesium Hydroxide Treatment Process for Stabilizing PFP Plutonium/Nitric Acid Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, Mark A.; Schmidt, Andrew J.; Delegard, Calvin H.; Silvers, Kurt L.; Baker, Aaron B.; Gano, Susan R.; Thornton, Brenda M.

    2000-09-28

    This document summarizes an evaluation of the magnesium hydroxide [Mg(OH)2] process to be used at the Hanford Plutonium Finishing Plant (PFP) for stabilizing plutonium/nitric acid solutions to meet the goal of stabilizing the plutonium in an oxide form suitable for storage under DOE-STD-3013-99. During the treatment process, nitric acid solutions bearing plutonium nitrate are neutralized with Mg(OH)2 in an air sparge reactor. The resulting slurry, containing plutonium hydroxide, is filtered and calcined. The process evaluation included a literature review and extensive laboratory- and bench-scale testing. The testing was conducted using cerium as a surrogate for plutonium to identify and quantify the effects of key processing variables on processing time (primarily neutralization and filtration time) and calcined product properties.

  13. Assessing control of postural stability in community-living older adults using performance-based limits of stability

    DEFF Research Database (Denmark)

    Jbabdi, Myriam; Boissy, Patrice; Hamel, Mathieu

    2008-01-01

    BACKGROUND: Balance disability measurements routinely used to identify fall risks in frail populations have limited value in the early detection of postural stability deficits in community-living older adults. The objectives of the study were to 1) measure performance-based limits of stability (LOS......) in community-living older adults and compare them to theoretical LOS computed from data proposed by the Balance Master system, 2) explore the feasibility of a new measurement approach based on the assessment of postural stability during weight-shifting tasks at performance-based LOS, 3) quantify intra......-session performance variability during multiple trials using the performance-based LOS paradigm. METHODS: Twenty-four healthy community-living older adults (10 men, 14 women) aged between 62 to 85 (mean age +/- sd, 71.5 +/- 6 yrs) participated in the study. Subjects' performance-based LOS were established by asking...

  14. On-Line Voltage Stability Assessment based on PMU Measurements

    DEFF Research Database (Denmark)

    Garcia-Valle, Rodrigo; P. Da Silva, Luiz C.; Nielsen, Arne Hejde

    2009-01-01

    This paper presents a method for on-line monitoring of risk voltage collapse based on synchronised phasor measurement. As there is no room for intensive computation and analysis in real-time, the method is based on the combination of off-line computation and on-line monitoring, which are correlat...... of critical buses obtained by phasor measurements are monitored in relation to the risk regions. Comprehensive studies demonstrate that the proposed method could assist operators to avoid voltage collapse events, by taking preventive or emergency actions.......This paper presents a method for on-line monitoring of risk voltage collapse based on synchronised phasor measurement. As there is no room for intensive computation and analysis in real-time, the method is based on the combination of off-line computation and on-line monitoring, which are correlated...... through statistic analysis. During the off-line analysis, a memory of high-risk situations following a pre-defined voltage stability criterion is obtained. Thereafter, basic statistics analyses are applied resulting in the definition of voltage regions. During on-line operation, voltage magnitudes...

  15. Transient stability improvement by nonlinear controllers based on tracking

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Juan M. [Centro de Investigacion y Estudios Avanzados, Guadalajara, Mexico. Av. Cientifica 1145. Col. El Bajio. Zapopan, Jal. 45015 (Mexico); Arroyave, Felipe Valencia; Correa Gutierrez, Rosa Elvira [Universidad Nacional de Colombia, Sede Medellin. Facultad de Minas, Escuela de Mecatronica (Colombia)

    2011-02-15

    This paper deals with the control problem in multi-machine electric power systems, which represent complex great scale nonlinear systems. Thus, the controller design is a challenging problem. These systems are subjected to different perturbations, such as short circuits, connection and/or disconnection of loads, lines, or generators. Then, the utilization of controllers which guarantee good performance under those perturbations is required in order to provide electrical energy to the loads with admissible stability margins. The proposed controllers are based on a systematic strategy, which calculate nonlinear controllers for generating units in a power plant, both for voltage and velocity regulation. The formulation allows designing controllers in a multi-machine power system without intricate calculations. Results on a power system of the open research indicate the proposition's suitability. The problem is formulated as a tracking problem. The designed controllers may be implemented in any electric power system. (author)

  16. Yield and nutrition of sunflower fertilized with sewage sludge stabilized by different processes

    Directory of Open Access Journals (Sweden)

    Altina Lacerda Nascimento

    2013-10-01

    Full Text Available The different methods of sewage sludge stabilization modify their physical chemical and biological properties, altering its efficiency when applied in agriculture. The objective of this study was to evaluate the nutrient levels in soil and the yield of sunflower fertilized with sewage sludge stabilized by different processes. The experiment was conducted in Cambisol, with the treatments: control (without fertilization, fertilization with sewage sludge solarized, composted, vermicomposted, limed and chemical fertilizer recommended for sunflower crop. The experimental design a randomized block with four replications. The different methods of sewage sludge treatment did not affect the yield; however, the application of sewage sludge, regardless the stabilization process adopted, was more effective than chemical fertilizer and the control treatment. Overall, fertilization with limed sewage sludge provided higher soil nutrients concentrations, while treatments with composted and vermicomposted sewage sludge showed higher levels of nutrients in the plant.

  17. Polyethylene encapsulatin of nitrate salt wastes: Waste form stability, process scale-up, and economics

    Energy Technology Data Exchange (ETDEWEB)

    Kalb, P.D.; Heiser, J.H. III; Colombo, P.

    1991-07-01

    A polyethylene encapsulation system for treatment of low-level radioactive, hazardous, and mixed wastes has been developed at Brookhaven National Laboratory. Polyethylene has several advantages compared with conventional solidification/stabilization materials such as hydraulic cements. Waste can be encapsulated with greater efficiency and with better waste form performance than is possible with hydraulic cement. The properties of polyethylene relevant to its long-term durability in storage and disposal environments are reviewed. Response to specific potential failure mechanisms including biodegradation, radiation, chemical attack, flammability, environmental stress cracking, and photodegradation are examined. These data are supported by results from extensive waste form performance testing including compressive yield strength, water immersion, thermal cycling, leachability of radioactive and hazardous species, irradiation, biodegradation, and flammability. The bench-scale process has been successfully tested for application with a number of specific problem'' waste streams. Quality assurance and performance testing of the resulting waste form confirmed scale-up feasibility. Use of this system at Rocky Flats Plant can result in over 70% fewer drums processed and shipped for disposal, compared with optimal cement formulations. Based on the current Rocky Flats production of nitrate salt per year, polyethylene encapsulation can yield an estimated annual savings between $1.5 million and $2.7 million, compared with conventional hydraulic cement systems. 72 refs., 23 figs., 16 tabs.

  18. Polyethylene encapsulatin of nitrate salt wastes: Waste form stability, process scale-up, and economics

    International Nuclear Information System (INIS)

    Kalb, P.D.; Heiser, J.H. III; Colombo, P.

    1991-07-01

    A polyethylene encapsulation system for treatment of low-level radioactive, hazardous, and mixed wastes has been developed at Brookhaven National Laboratory. Polyethylene has several advantages compared with conventional solidification/stabilization materials such as hydraulic cements. Waste can be encapsulated with greater efficiency and with better waste form performance than is possible with hydraulic cement. The properties of polyethylene relevant to its long-term durability in storage and disposal environments are reviewed. Response to specific potential failure mechanisms including biodegradation, radiation, chemical attack, flammability, environmental stress cracking, and photodegradation are examined. These data are supported by results from extensive waste form performance testing including compressive yield strength, water immersion, thermal cycling, leachability of radioactive and hazardous species, irradiation, biodegradation, and flammability. The bench-scale process has been successfully tested for application with a number of specific ''problem'' waste streams. Quality assurance and performance testing of the resulting waste form confirmed scale-up feasibility. Use of this system at Rocky Flats Plant can result in over 70% fewer drums processed and shipped for disposal, compared with optimal cement formulations. Based on the current Rocky Flats production of nitrate salt per year, polyethylene encapsulation can yield an estimated annual savings between $1.5 million and $2.7 million, compared with conventional hydraulic cement systems. 72 refs., 23 figs., 16 tabs

  19. Process Optimization for Biodiesel Production from Corn Oil and Its Oxidative Stability

    Directory of Open Access Journals (Sweden)

    N. El Boulifi

    2010-01-01

    Full Text Available Response surface methodology (RSM based on central composite design (CCD was used to optimize biodiesel production process from corn oil. The process variables, temperature and catalyst concentration were found to have significant influence on biodiesel yield. The optimum combination derived via RSM for high corn oil methyl ester yield (99.48% was found to be 1.18% wt catalyst concentration at a reaction temperature of 55.6∘C. To determine how long biodiesel can safely be stored, it is desirable to have a measurement for the stability of the biodiesel against such oxidation. Storage time and oxygen availability have been considered as possible factors influencing oxidative instability. Biodiesel from corn oil was stored for a period of 30 months, and the physico-chemical parameters of samples were measured at regular interval of time. Results show that the acid value (AV, peroxide value (PV, and viscosity (ν increased while the iodine value (IV decreased. These parameters changed very significantly when the sample was stored under normal oxygen atmosphere. However, the ν, AV, and IV of the biodiesel sample which was stored under argon atmosphere were within the limit by the European specifications (EN 14214.

  20. Experimental and theoretical studies of the colloidal stability of nanoparticles-a general interpretation based on stability maps.

    Science.gov (United States)

    Segets, Doris; Marczak, Renata; Schäfer, Stefan; Paula, Carolin; Gnichwitz, Jan-Frederik; Hirsch, Andreas; Peukert, Wolfgang

    2011-06-28

    The current work addresses the understanding of the stabilization of nanoparticles in suspension. Specifically, we study ZnO in ethanol for which the influence of particle size and reactant ratio as well as surface coverage on colloidal stability in dependence of the purification progress was investigated. The results revealed that the well-known ζ-potential determines not only the colloidal stability but also the surface coverage of acetate groups bound to the particle surface. The acetate groups act as molecular spacers between the nanoparticles and prevent agglomeration. Next to DLVO calculations based on the theory of Derjaguin, Landau, Verwey and Overbeek using a core-shell model we find that the stability is better understood in terms of dimensionless numbers which represent attractive forces as well as electrostatic repulsion, steric effects, transport properties, and particle concentration. Evaluating the colloidal stability in dependence of time by means of UV-vis absorption measurements a stability map for ZnO is derived. From this map it becomes clear that the dimensionless steric contribution to colloidal stability scales with a stability parameter including dimensionless repulsion and attraction as well as particle concentration and diffusivity of the particles according to a power law with an exponent of -0.5. Finally, we show that our approach is valid for other stabilizing molecules like cationic dendrons and is generally applicable for a wide range of other material systems within the limitations of vanishing van der Waals forces in refractive index matched situations, vanishing ζ-potential and systems without a stabilizing shell around the particle surface.

  1. Base Stabilization Guidance and Additive Selection for Pavement Design and Rehabilitation

    Science.gov (United States)

    2017-12-01

    Significant improvements have been made in base stabilization practice that include design specifications and methodology, experience with the selection of stabilizing additives, and equipment for distribution and uniform blending of additives. For t...

  2. New results on the robust stability of PID controllers with gain and phase margins for UFOPTD processes.

    Science.gov (United States)

    Jin, Q B; Liu, Q; Huang, B

    2016-03-01

    This paper considers the problem of determining all the robust PID (proportional-integral-derivative) controllers in terms of the gain and phase margins (GPM) for open-loop unstable first order plus time delay (UFOPTD) processes. It is the first time that the feasible ranges of the GPM specifications provided by a PID controller are given for UFOPTD processes. A gain and phase margin tester is used to modify the original model, and the ranges of the margin specifications are derived such that the modified model can be stabilized by a stabilizing PID controller based on Hermite-Biehlers Theorem. Furthermore, we obtain all the controllers satisfying a given margin specification. Simulation studies show how to use the results to design a robust PID controller. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  3. The Effects of pH and Heat Treatment Processing on the Stability of ...

    African Journals Online (AJOL)

    This study was carried out to investigate the effects of pH and heat treatment processing on stability and natural food colours used in dairy products. A repeated laboratory experiment was conducted in which loss of colour intensity or change in shade of natural food colours used in acid and nearly neutral dairy products at ...

  4. Leaching of concrete : the leaching process : extrapolation of deterioration : effect on the structural stability

    OpenAIRE

    Fagerlund, Göran

    2000-01-01

    The leaching process when water attacks concrete, and the effect of leaching on the strength and durability of a concrete structure, is analysed theoretically. Technique for prediction of the future leaching and structural stability is outlined. The analysis is to a certain extent supported by data from literature. The leaching process is divided in five different types: 1: Pure surface leaching 2: Surface leaching involving erosion 3: Homogeneous leaching over the entire structure 4...

  5. Rapid evaluation of machine tools with position-dependent milling stability based on response surface model

    Directory of Open Access Journals (Sweden)

    Li Zhang

    2016-03-01

    Full Text Available The milling stability is one of the important evaluation criterions of dynamic characteristics of machine tools, and it is of great importance for machine tools’ design and manufacturing. The milling stability of machine tools generally varies with the position combinations of moving parts. The traditional milling stability analysis of machine tools is based on some specific positions in the whole workspace of machine tools, and the results are not comprehensive. Furthermore, it is very time-consuming for operation and calculation to complete analysis of multiple positions. A new method to rapidly evaluate the stability of machine tools with position dependence is developed in this article. In this method, the key position combinations of moving parts are set as the samples of calculation to calculate the dynamic characteristics of machine tools with SAMCEF finite element simulation analysis software. Then the minimum critical axial cutting depth of each sample is obtained. The relationship between the position and the value of minimum critical axial cutting depth at any position in the whole workspace can be obtained through established response surface model. The precision of the response surface model is evaluated and the model could be used to rapidly evaluate the milling stability of machine tools with position dependence. With a precision horizontal machining center with box-in-box structure as an example, the value of minimum critical axial cutting depth at any position is shown. This method of rapid evaluation of machine tools with position-dependent stability avoids complicated theoretical calculation, so it can be easily adopted by engineers and technicians in the phase of design process of machine tools.

  6. Immobilization, stabilization and patterning techniques for enzyme based sensor systems.

    Energy Technology Data Exchange (ETDEWEB)

    Flounders, A.W.; Carichner, S.C.; Singh, A.K.; Volponi, J.V.; Schoeniger, J.S.; Wally, K.

    1997-01-01

    Sandia National Laboratories has recently opened the Chemical and Radiation Detection Laboratory (CRDL) in Livermore CA to address the detection needs of a variety of government agencies (e.g., Department of Energy, Environmental Protection Agency, Department of Agriculture) as well as provide a fertile environment for the cooperative development of new industrial technologies. This laboratory consolidates a variety of existing chemical and radiation detection efforts and enables Sandia to expand into the novel area of biochemically based sensors. One aspect of this biosensor effort is further development and optimization of enzyme modified field effect transistors (EnFETs). Recent work has focused upon covalent attachment of enzymes to silicon dioxide and silicon nitride surfaces for EnFET fabrication. They are also investigating methods to pattern immobilized proteins; a critical component for development of array-based sensor systems. Novel enzyme stabilization procedures are key to patterning immobilized enzyme layers while maintaining enzyme activity. Results related to maximized enzyme loading, optimized enzyme activity and fluorescent imaging of patterned surfaces will be presented.

  7. Model-based chatter stability prediction and detection for the turning of a flexible workpiece

    Science.gov (United States)

    Lu, Kaibo; Lian, Zisheng; Gu, Fengshou; Liu, Hunju

    2018-02-01

    Machining long slender workpieces still presents a technical challenge on the shop floor due to their low stiffness and damping. Regenerative chatter is a major hindrance in machining processes, reducing the geometric accuracies and dynamic stability of the cutting system. This study has been motivated by the fact that chatter occurrence is generally in relation to the cutting position in straight turning of slender workpieces, which has seldom been investigated comprehensively in literature. In the present paper, a predictive chatter model of turning a tailstock supported slender workpiece considering the cutting position change during machining is explored. Based on linear stability analysis and stiffness distribution at different cutting positions along the workpiece, the effect of the cutting tool movement along the length of the workpiece on chatter stability is studied. As a result, an entire stability chart for a single cutting pass is constructed. Through this stability chart the critical cutting condition and the chatter onset location along the workpiece in a turning operation can be estimated. The difference between the predicted tool locations and the experimental results was within 9% at high speed cutting. Also, on the basis of the predictive model the dynamic behavior during chatter that when chatter arises at some cutting location it will continue for a period of time until another specified location is arrived at, can be inferred. The experimental observation is in good agreement with the theoretical inference. In chatter detection respect, besides the delay strategy and overlap processing technique, a relative threshold algorithm is proposed to detect chatter by comparing the spectrum and variance of the acquired acceleration signals with the reference saved during stable cutting. The chatter monitoring method has shown reliability for various machining conditions.

  8. On the stability and compressive nonlinearity of a physiologically based model of the cochlea

    Energy Technology Data Exchange (ETDEWEB)

    Nankali, Amir [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan (United States); Grosh, Karl [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan (United States); Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan (United States)

    2015-12-31

    Hearing relies on a series of coupled electrical, acoustical (fluidic) and mechanical interactions inside the cochlea that enable sound processing. A positive feedback mechanism within the cochlea, called the cochlear amplifier, provides amplitude and frequency selectivity in the mammalian auditory system. The cochlear amplifier and stability are studied using a nonlinear, micromechanical model of the Organ of Corti (OoC) coupled to the electrical potentials in the cochlear ducts. It is observed that the mechano-electrical transduction (MET) sensitivity and somatic motility of the outer hair cell (OHC), control the cochlear stability. Increasing MET sensitivity beyond a critical value, while electromechanical coupling coefficient is within a specific range, causes instability. We show that instability in this model is generated through a supercritical Hopf bifurcation. A reduced order model of the system is approximated and it is shown that the tectorial membrane (TM) transverse mode effect on the dynamics is significant while the radial mode can be simplified from the equations. The cochlear amplifier in this model exhibits good agreement with the experimental data. A comprehensive 3-dimensional model based on the cross sectional model is simulated and the results are compared. It is indicated that the global model qualitatively inherits some characteristics of the local model, but the longitudinal coupling along the cochlea shifts the stability boundary (i.e., Hopf bifurcation point) and enhances stability.

  9. Stabilization of Foam Lamella Using Novel Surface-Grafted Nanocellulose-Based Nanofluids.

    Science.gov (United States)

    Wei, Bing; Li, Hao; Li, Qinzhi; Wen, Yangbing; Sun, Lin; Wei, Peng; Pu, Wanfen; Li, Yibo

    2017-05-30

    To solve the potential risk of present oilfield chemistries to subterranean environment, our group contributes to the development of "green" petroleum production processes. This proof-of-concept research studied the well-defined nanocellulose-based nanofluids, i.e., original (NC), AMPS grafted (NC-KY), and AMPS and hydrophobic chains grafted (NC-KYSS), in stabilizing foam lamella for potential use in enhanced oil recovery (EOR). The data showed that the collaboration of the surface-functional nanocellulose considerately improved the foam stability particularly in the presence of hydrocarbons due to the thickened foam film coupled with the molecular interactions at interior lamella. Since the grafted AMPS and alkyl chains, NC-KYSS noticeably enhanced foam quality compared against NC and NC-KY. With the increase in gas pressure, the lamella stabilizing effect of NC-KYSS became increasingly significant. The coflowing behaviors of foam with oleic phase in porous media were examined in a five-spot visualization micromodel (15 cm × 15 cm × 1 cm) and identified using a digital analysis method. The defoaming/destabilizing effect of hydrocarbons was fairly notable in porous media, causing the foam to finger through the formed "oil bank". However, a tough displacement front was constructed when the surfactant synergized with NC-KYSS due to the stabilized foam lamella and 12% of incremental oil recovery was produced.

  10. Preparation, melting behavior and thermal stability of poly(lactic acid)/poly(propylene carbonate) blends processed by vane extruder

    International Nuclear Information System (INIS)

    Zou, Wei; Chen, Rongyuan; Zhang, Haichen; Qu, Jinping

    2016-01-01

    Poly (lactic acid) (PLA)/Poly (propylene carbonate) (PPC) blends were prepared by vane extruder which is a type of novel polymer processing extruder based on elongation force field. Scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermogravimetric (TG) were used respectively to analyze the compatibility, the melting behavior and thermal stability properties of PLA/PPC blends affected by the different content of PPC. The results showed that with the increase of the PPC content, the glass transition temperature of PLA was reduced, and the glass transition temperature of PPC was increased, which indicated that PLA and PPC had partial compatibility. The cold crystallization temperature of PLA increased with the increase of the PPC content, which showed that PPC hindered the cold crystallization process of PLA. The addition of PPC had little impact on the melting process of PLA, and the melting temperature of PLA was almost kept the same value. Thermogravimetric analysis showed that the thermal stability of PPC was worse than that of PLA, the addition of PPC reduced the thermal stability of PLA.

  11. Preparation, melting behavior and thermal stability of poly(lactic acid)/poly(propylene carbonate) blends processed by vane extruder

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Wei, E-mail: zw55624@163.com; Chen, Rongyuan; Zhang, Haichen; Qu, Jinping, E-mail: jpqu@scut.edu.cn [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou 510640 (China)

    2016-03-09

    Poly (lactic acid) (PLA)/Poly (propylene carbonate) (PPC) blends were prepared by vane extruder which is a type of novel polymer processing extruder based on elongation force field. Scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermogravimetric (TG) were used respectively to analyze the compatibility, the melting behavior and thermal stability properties of PLA/PPC blends affected by the different content of PPC. The results showed that with the increase of the PPC content, the glass transition temperature of PLA was reduced, and the glass transition temperature of PPC was increased, which indicated that PLA and PPC had partial compatibility. The cold crystallization temperature of PLA increased with the increase of the PPC content, which showed that PPC hindered the cold crystallization process of PLA. The addition of PPC had little impact on the melting process of PLA, and the melting temperature of PLA was almost kept the same value. Thermogravimetric analysis showed that the thermal stability of PPC was worse than that of PLA, the addition of PPC reduced the thermal stability of PLA.

  12. Optimal placement of unified power flow controllers to improve dynamic voltage stability using power system variable based voltage stability indices.

    Science.gov (United States)

    Albatsh, Fadi M; Ahmad, Shameem; Mekhilef, Saad; Mokhlis, Hazlie; Hassan, M A

    2015-01-01

    This study examines a new approach to selecting the locations of unified power flow controllers (UPFCs) in power system networks based on a dynamic analysis of voltage stability. Power system voltage stability indices (VSIs) including the line stability index (LQP), the voltage collapse proximity indicator (VCPI), and the line stability index (Lmn) are employed to identify the most suitable locations in the system for UPFCs. In this study, the locations of the UPFCs are identified by dynamically varying the loads across all of the load buses to represent actual power system conditions. Simulations were conducted in a power system computer-aided design (PSCAD) software using the IEEE 14-bus and 39- bus benchmark power system models. The simulation results demonstrate the effectiveness of the proposed method. When the UPFCs are placed in the locations obtained with the new approach, the voltage stability improves. A comparison of the steady-state VSIs resulting from the UPFCs placed in the locations obtained with the new approach and with particle swarm optimization (PSO) and differential evolution (DE), which are static methods, is presented. In all cases, the UPFC locations given by the proposed approach result in better voltage stability than those obtained with the other approaches.

  13. High level model predictive control for plug-and-play process control with stability guaranty

    DEFF Research Database (Denmark)

    Michelsen, Axel Gottlieb; Stoustrup, Jakob

    2010-01-01

    In this paper a method for designing a stabilizing high level model predictive controller for a hierarchical plug- and-play process is presented. This is achieved by abstracting the lower layers of the controller structure as low order models with uncertainty and by using a robust model predictive...... controller for generating the references for these. A simulation example, in which the actuators in a process control system are changed, is reported to show the potential of this approach for plug and play process control....

  14. Methodology for the effective stabilization of tin-oxide-based oxidation/reduction catalysts

    Science.gov (United States)

    Jordan, Jeffrey D. (Inventor); Schryer, David R. (Inventor); Davis, Patricia P. (Inventor); Leighty, Bradley D. (Inventor); Watkins, Anthony N. (Inventor); Schryer, Jacqueline L. (Inventor); Oglesby, Donald M. (Inventor); Gulati, Suresh T. (Inventor); Summers, Jerry C. (Inventor)

    2011-01-01

    The invention described herein involves a novel approach to the production of oxidation/reduction catalytic systems. The present invention serves to stabilize the tin oxide reducible metal-oxide coating by co-incorporating at least another metal-oxide species, such as zirconium. In one embodiment, a third metal-oxide species is incorporated, selected from the group consisting of cerium, lanthanum, hafnium, and ruthenium. The incorporation of the additional metal oxide components serves to stabilize the active tin-oxide layer in the catalytic process during high-temperature operation in a reducing environment (e.g., automobile exhaust). Moreover, the additional metal oxides are active components due to their oxygen-retention capabilities. Together, these features provide a mechanism to extend the range of operation of the tin-oxide-based catalyst system for automotive applications, while maintaining the existing advantages.

  15. Stability analysis of grid-connected PV systems based on impedance frequency response

    OpenAIRE

    Rodríguez Villarreal, José Raúl; Biel Solé, Domingo; Guinjoan Gispert, Francisco

    2011-01-01

    The increase of distributed generation on electric networks has raised the concern of grid stability, among other issues. The PV generators connected to the grid have to deal with varying consumption and generation scenarios, however, this may affect the performance and stability of the generators themselves, as well as the grid. This document presents an analytical stability method to maintain the grid stability by adjusting the generator control parameters based on the ...

  16. High stability vector-based direct power control for DFIG-based wind turbine

    DEFF Research Database (Denmark)

    Zhu, Rongwu; Chen, Zhe; Wu, Xiaojie

    2015-01-01

    This paper proposes an improved vector-based direct power control (DPC) strategy for the doubly-fed induction generator (DFIG)-based wind energy conversion system. Based on the small signal model, the proposed DPC improves the stability of the DFIG, and avoids the DFIG operating in the marginal...... stable region (the real part of eigenvalue is equal to zero). The vector-based DPC combines with a space vector modulation technique to achieve a constant switching frequency. The simulation and experimental results clearly validate the effectiveness and feasibility of the proposed vector-based DPC...

  17. Stability of cassava flour-based food bars

    Directory of Open Access Journals (Sweden)

    Erica Caroline da Silva

    2013-03-01

    Full Text Available The consumption of Brazilian cassava has been reduced due to a lack of adjustment to the modern lifestyle. To reverse this trend, new products could be developed specifically targeted to high-value niche markets. Cereal bars stand out as fast food high in nutritional value. A bar formula mimicking cereal bars was prepared using a mixture of Brazilian cassava flour, hydrogenated vegetable fat, dried bananas, ground cashew nuts, and glucose syrup. After being pressed, the bars were dried for 1 hour at 65 °C, packaged in films, and stored under ambient conditions. Its stability was continuously monitored for 210 days in order to ensure its safety and enable its introduction to the market. Texture loss was observed in the packed bars after 90 days of storage, but the sensory characteristics allowed the testers to perceive this tendency after only 30 days of storage. However, chemical, physical, and microbial analyses confirmed that the bars were safe for consumption for 180 days. The results showed that a 45 g cassava flour-based bar enriched with nuts and dried fruits can meet 6% of the recommended daily fiber intake with a caloric value between that of the common cereal bar and that of an energy bar. Adapting the formula with ingredients (fruits, nuts from different regions of Brazil may add value to this traditional product as a fast food.

  18. Business Process Modelling based on Petri nets

    Directory of Open Access Journals (Sweden)

    Qin Jianglong

    2017-01-01

    Full Text Available Business process modelling is the way business processes are expressed. Business process modelling is the foundation of business process analysis, reengineering, reorganization and optimization. It can not only help enterprises to achieve internal information system integration and reuse, but also help enterprises to achieve with the external collaboration. Based on the prototype Petri net, this paper adds time and cost factors to form an extended generalized stochastic Petri net. It is a formal description of the business process. The semi-formalized business process modelling algorithm based on Petri nets is proposed. Finally, The case from a logistics company proved that the modelling algorithm is correct and effective.

  19. Handling Stability of Tractor Semitrailer Based on Handling Diagram

    Directory of Open Access Journals (Sweden)

    Ren Yuan-yuan

    2012-01-01

    Full Text Available Handling instability is a serious threat to driving safety. In order to analyze the handling stability of a tractor semitrailer, a handling diagram can be used. In our research, considering the impact of multiple nonsteering rear axles and nonlinear characteristics of tires on vehicle handling stability, the handling equations are developed for description of stability of tractor semi-trailer. Then we obtain handling diagrams so as to study the influence of driving speed, loaded mass, and fifth wheel lead on vehicle handling stability. The analysis results show that the handling stability of a tractor semi-trailer when the tractor has two nonsteering rear axles is better than that when the tractor has only one nonsteering rear axle. While the stability in the former case is slightly influenced by driving speed and loaded mass, the latter is strongly influenced by both. The fifth wheel lead is found to only slightly influence handling stability for both tractor semi-trailers. Therefore, to ensure the driving safety of tractor semi-trailers when the tractor has only one nonsteering rear axle, much stricter restraints should be imposed on driving speed, and the loaded mass must not exceed the rated load of the trailer.

  20. Process-Based Quality (PBQ) Tools Development

    Energy Technology Data Exchange (ETDEWEB)

    Cummins, J.L.

    2001-12-03

    The objective of this effort is to benchmark the development of process-based quality tools for application in CAD (computer-aided design) model-based applications. The processes of interest are design, manufacturing, and quality process applications. A study was commissioned addressing the impact, current technologies, and known problem areas in application of 3D MCAD (3-dimensional mechanical computer-aided design) models and model integrity on downstream manufacturing and quality processes. The downstream manufacturing and product quality processes are profoundly influenced and dependent on model quality and modeling process integrity. The goal is to illustrate and expedite the modeling and downstream model-based technologies for available or conceptual methods and tools to achieve maximum economic advantage and advance process-based quality concepts.

  1. Ceramic stabilization of hazardous wastes: a high performance room temperature process

    International Nuclear Information System (INIS)

    Maloney, M.D.

    1996-01-01

    ANL has developed a room-temperature process for converting hazardous materials to a ceramic structure. It is similar to vitrification but is achieved at low cost, similar to conventional cement stabilization. The waste constituents are both chemically stabilized and physically encapsulated, producing very low leaching levels and the potential for delisting. The process, which is pH-insensitive, is ideal for inorganic sludges and liquids, as well as mixed chemical-radioactive wastes, but can also handle significant percentages of salts and even halogenated organics. High waste loadings are possible and densification occurs,so that volumes are only slightly increased and in some cases (eg, incinerator ash) are reduced. The ceramic product has strength and weathering properties far superior to cement products

  2. Stabilization of Gambier Process Wastewater and Its Aplication as Silk Dye

    Directory of Open Access Journals (Sweden)

    Failisnur Failisnur

    2013-06-01

    Full Text Available Gambier liquid waste is a by-product from gambier (Uncaria gambier Roxb. processing plant,  which is still contains a lot of untapped tannin. This waste could be used for textile dyes, but it is easily damaged during storage. So, the aim of this research is to treat gambier liquid waste so it could be used as silk dye. This research was carried out by concentrating the waste and using stabilizers such as lime (K, alum (T, lotus (F. The parameters tested include pH and fungal growth for up to three months. The results of the process could generate several different colors which is brownish red, brownish yellow and dark green. The waste could save more than 3 months. The color of the waste generated depends on stabilizer type and pH. The use  waste on silk produced brownish red color, golden yellow  and moss green to dark green.

  3. Assisting people with Nystagmus through image stabilization: Using an ARX model to overcome processing delays.

    Science.gov (United States)

    Polzer, Stephan; Miesenberger, Klaus

    2017-07-01

    Pathological Nystagmus is characterized by an unintended and involuntary eye-movement, which tends to impact on visual acuity. Today only view therapies (for instance medication or surgeries) to treat nystagmus are at hand and the existing therapies only show partial improvement. Only general Assistive Technology (AT) solutions like glasses, screen magnifiers, speech output, display adaptation and concepts holders are at hand to support daily living. More specific ATs to reduce the impact of nystagmus are missing. This paper presents conceptual research and feasibility studies with the attempt to reduce the impact of nystagmus by stabilizing the image on the retina (digital Retinal Image Stabilization) by moving the digital image synchronal with the unintended eye movement using gaze contingent display technology. Further an identification and validation process using recorded eye-movements is presented since the synchronization approach relies on predicting eye-movements to reduce the impact of delays due to processing time.

  4. A mesophilic anaerobic digester for treating food waste: process stability and microbial community analysis using pyrosequencing.

    Science.gov (United States)

    Li, Lei; He, Qin; Ma, Yao; Wang, Xiaoming; Peng, Xuya

    2016-04-25

    Anaerobic digesters become unstable when operated at a high organi c loading rate (OLR). Investigating the microbial community response to OLR disturbance is helpful for achieving efficient and stable process operation. However, previous studies have only focused on community succession during different process stages. How does community succession influence process stability? Is this kind of succession resilient? Are any key microbial indicator closely related to process stability? Such relationships between microbial communities and process stability are poorly understood. In this study, a mesophilic anaerobic digester for treating food waste (FW) was operated to study the microbial diversity and dynamicity due to OLR disturbance. Overloading resulted in proliferation of acidogenic bacteria, and the resulting high volatile fatty acid (VFA) yield triggered an abundance of acetogenic bacteria. However, the abundance and metabolic efficiency of hydrogenotrophic methanogens decreased after disturbance, and as a consequence, methanogens and acetogenic bacteria could not efficiently complete the syntrophy. This stress induced the proliferation of homoacetogens as alternative hydrogenotrophs for converting excessive H2 to acetate. However, the susceptible Methanothrix species also failed to degrade the excessive acetate. This metabolic imbalance finally led to process deterioration. After process recovery, the digester gradually returned to its original operational conditions, reached close to its original performance, and the microbial community profile achieved a new steady-state. Interestingly, the abundance of Syntrophomonas and Treponema increased during the deteriorative stage and rebounded after disturbance, suggesting they were resilient groups. Acidogenic bacteria showed high functional redundancy, rapidly adapted to the increased OLR, and shaped new microbial community profiles. The genera Syntrophomonas and Treponema were resilient groups. This observation

  5. The Application of Vector Fitting to Eigenvalue-based Harmonic Stability Analysis

    DEFF Research Database (Denmark)

    Dowlatabadi, Mohammadkazem Bakhshizadeh; Yoon, Changwoo; Hjerrild, Jesper

    2017-01-01

    Participation factor analysis is an interesting feature of the eigenvalue-based stability analysis in a power system, which enables the developers to identify the problematic elements in a multi-vendor project like in an offshore wind power plant. However, this method needs a full state space model...... of the elements that is not always possible to have in a competitive world due to confidentiality. In this paper, by using an identification method, the state space models for power converters are extracted from the provided data by the suppliers. Some uncertainties in the identification process are also...

  6. Modification of Yellow River Sediment Based Stabilized Earth Bricks

    OpenAIRE

    Junxia Liu; Ran Hai; Lei Zhang

    2016-01-01

    This paper presents an experimental study on the microstructure and performance of stabilized earth bricks prepared from the Yellow River sediment. The sediment is modified by inorganic cementitious material, polymer bonding agent, and jute fibre. The results show that the sediment is preliminarily consolidated when the mixture ratio of activated sediment/cementitious binder/sand is 65/25/10. Compressive strength and softening coefficient of stabilized earth bricks is further improved by poly...

  7. Lignin-based carbon fibers: Carbon nanotube decoration and superior thermal stability

    KAUST Repository

    Xu, Xuezhu

    2014-08-23

    Lignin-based carbon fibers (CFs) decorated with carbon nanotubes (CNTs) were synthesized and their structure, thermal stability and wettability were systematically studied. The carbon fiber precursors were produced by electrospinning lignin/polyacrylonitrile solutions. CFs were obtained by pyrolyzing the precursors and CNTs were subsequently grown on the CFs to eventually achieve a CF–CNT hybrid structure. The processes of pyrolysis and CNT growth were conducted in a tube furnace using different conditions and the properties of the resultant products were studied and compared. The CF–CNT hybrid structure produced at 850 °C using a palladium catalyst showed the highest thermal stability, i.e., 98.3% residual weight at 950 °C. A mechanism for such superior thermal stability was postulated based on the results from X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, and electron energy loss spectroscopy analyses. The dense CNT decoration was found to increase the hydrophobicity of the CFs.

  8. Robustness and cognition in stabilization problem of dynamical systems based on asymptotic methods

    Science.gov (United States)

    Dubovik, S. A.; Kabanov, A. A.

    2017-01-01

    The problem of synthesis of stabilizing systems based on principles of cognitive (logical-dynamic) control for mobile objects used under uncertain conditions is considered. This direction in control theory is based on the principles of guaranteeing robust synthesis focused on worst-case scenarios of the controlled process. The guaranteeing approach is able to provide functioning of the system with the required quality and reliability only at sufficiently low disturbances and in the absence of large deviations from some regular features of the controlled process. The main tool for the analysis of large deviations and prediction of critical states here is the action functional. After the forecast is built, the choice of anti-crisis control is the supervisory control problem that optimizes the control system in a normal mode and prevents escape of the controlled process in critical states. An essential aspect of the approach presented here is the presence of a two-level (logical-dynamic) control: the input data are used not only for generating of synthesized feedback (local robust synthesis) in advance (off-line), but also to make decisions about the current (on-line) quality of stabilization in the global sense. An example of using the presented approach for the problem of development of the ship tilting prediction system is considered.

  9. Stabilization of açaí (Euterpe oleracea Mart. juice by the microfiltration process

    Directory of Open Access Journals (Sweden)

    Flávio Caldeira Silva

    2016-01-01

    Full Text Available Açaí berry, a Brazilian palm fruit widely distributed in northern South America, is acknowledged for its functional properties such as high antioxidant capacity and anti-inflammatory activities. Although the açaí juice is highly appreciated in Brazil and even worldwide, its commercialization is still limited. Microfiltration process is largely applied in juice processing, eliminating many of the traditional processing steps and reducing time, energy and addition of clarifying agents. Furthermore, microfiltration process may eliminate microorganisms and compounds responsible for turbidity in the juice. Current assay applies a microfiltration process to obtain a stabilized açaí permeate pulp. Microfiltrations of açaí pulp were carried out in a dead end configuration with a flat membrane of 0.22 μm pore size. Permeate pulp was characterized according to its turbidity, lipid concentration and microbiological analysis. Initial permeate flux was 103 kg m-2 h-1. After an initial flux decline during 30 min., due to membrane compaction and fouling occurrences, flux was stabilized at 20 kg m-2 h-1. The microfiltration process reduced the initial açaí pulp turbidity by 99.98% and lipids were not identified in the permeate. Microbiological analysis showed that the contamination by microorganism decreased in the permeate pulp when compared to that in raw açaí pulp.

  10. Process stability during fiber laser-arc hybrid welding of thick steel plates

    Science.gov (United States)

    Bunaziv, Ivan; Frostevarg, Jan; Akselsen, Odd M.; Kaplan, Alexander F. H.

    2018-03-01

    Thick steel plates are frequently used in shipbuilding, pipelines and other related heavy industries, and are usually joined by arc welding. Deep penetration laser-arc hybrid welding could increase productivity but has not been thoroughly investigated, and is therefore usually limited to applications with medium thickness (5-15 mm) sections. A major concern is process stability, especially when using modern welding consumables such as metal-cored wire and advanced welding equipment. High speed imaging allows direct observation of the process so that process behavior and phenomena can be studied. In this paper, 45 mm thick high strength steel was welded (butt joint double-sided) using the fiber laser-MAG hybrid process utilizing a metal-cored wire without pre-heating. Process stability was monitored under a wide range of welding parameters. It was found that the technique can be used successfully to weld thick sections with appropriate quality when the parameters are optimized. When comparing conventional pulsed and the more advanced cold metal transfer pulse (CMT+P) arc modes, it was found that both can provide high quality welds. CMT+P arc mode can provide more stable droplet transfer over a limited range of travel speeds. At higher travel speeds, an unstable metal transfer mechanism was observed. Comparing leading arc and trailing arc arrangements, the leading arc configuration can provide higher quality welds and more stable processing at longer inter-distances between the heat sources.

  11. Use of cement-fly ash-based stabilization techniques for the treatment of waste containing aromatic contaminants

    Science.gov (United States)

    Banaszkiewicz, Kamil; Marcinkowski, Tadeusz

    2017-11-01

    Research on evaluation of evaporation rate of volatile organic compounds from soil beds during processing is presented. For the experiment, soil samples were prepared with the same amounts of benzene and stabilized using a mixture of CEMI 42.5R cement and fly ash from pit-coal combustion. Solidification of soils contaminated with BTEX hydrocarbons using hydraulic binders involves a risk of releasing vapours of these compounds during homogenization of waste with stabilizing mixture introduced and its dilution with water. The primary purposes of the research were: analysis of benzene volume emitted from soil during stabilization/solidification process and characterization of factors that may negatively affect the quality of measurements/the course of stabilization process. Analysis of benzene emission intensity during the process was based on concentration (C6H6) values, recorded with flame-ionization detector above the surface of reacting mixture. At the same time, gaseous contaminants emitted during waste stabilization were passed through pipes filled with activated carbon (SCK, Anasorb CSC). Benzene vapours adsorbed on activated carbon were subjected to analysis using gas chromatograph Varian 450-GC. Evaporation characteristics of benzene during processing contaminated soils revealed the stages creating the highest danger to workers' health, as well as a need for actions connected with modification of technological line.

  12. Vision Based Displacement Detection for Stabilized UAV Control on Cloud Server

    Directory of Open Access Journals (Sweden)

    Hyeok-June Jeong

    2016-01-01

    Full Text Available Nowadays, image processing solution is used in many fields such as traffic information systems and illegal intrusion detection systems. Now, to assist with the control of camera-equipped devices, appropriate image processing techniques are needed for moving rather than fixed observers. For achieving this goal, an algorithm should derive the desired results quickly and accurately; thus, this paper considers two characteristics: functional performance (reliability and temporal performance (efficiency. Reliability means how well the desired results can be achieved, and efficiency means how quickly the result can be calculated. This paper suggests an optimized real-time image algorithm based on the integration of the optical flow and Speeded-Up Robust Features (SURF algorithms. This algorithm determines horizontal or vertical movement of the camera and then extracts its displacement. The proposed algorithm can be used to stabilize an Unmanned Aerial Vehicle (UAV in situations where it is drifting due to inertia and external forces, like wind, in parallel. The proposed algorithm is efficient in achieving drift stabilization by movement detection; however, it is not appropriate for image processing in small UAVs. To solve this problem, this study proposes an image processing method that uses a high-performance computer.

  13. Olive-oil nanocapsules stabilized by HSA: influence of processing variables on particle properties

    Energy Technology Data Exchange (ETDEWEB)

    Molina-Bolívar, J. A., E-mail: jmb@uma.es [University of Málaga, Department of Applied Physics II, Engineering School (Spain); Galisteo-González, F. [University of Granada, Department of Applied Physics (Spain)

    2015-10-15

    Liquid lipid nanocapsules (LLN) are considered to be promising drug carriers in the medical field. The size and the surface charge of these nanocarriers are of major importance, affecting their bioavailability and the in vivo behaviour after intravenous injection. This research provides a comprehensive study on the preparation of olive-oil nanocapsules stabilized with a human serum albumin shell (HSA). LLN were prepared by modified solvent-displacement method. Numerous experimental variables were examined in order to characterize their impact on LLN size, distribution, and electrophoretic mobility. Physicochemical parameters of LLN were controlled by adjusting the nanodroplet stabilizing shell of adsorbed protein molecules, which was affected by the oil:HSA ratio, pH, and ionic strength of aqueous medium. The stronger the repulsion between adsorbed HSA molecules, the smaller and more monodisperse the particles proved. Other process parameters, including the ethanol:acetone ratio, organic:aqueous phase ratio, speed of organic-phase injection, and stirring rate were examined to achieve optimum preparation conditions. LLN produced by our standardized formulation were in the range of 170–175 nm with low polydispersity index (<0.1). Long-term colloidal stability of samples was evaluated after 6 months of storage. Efficient incorporation of curcumin, a model for a water-insoluble drug, into olive-oil nanocapsules was achieved (90 %). Encapsulation of curcumin into LLN had a stabilizing effect with respect to drug photodecomposition compared to that of the free molecule in solution.

  14. Comparison of UPFC-Based Stabilizer and PSS Performances on Damping of Power System Oscillations

    OpenAIRE

    M. R. Meshkatoddini; M. Majidi; M. Sadeghierad; H. Lesani

    2009-01-01

    This paper establishes the linearized Phillips-Heffron model of a power system equipped with UPFC and demonstrates the application of the model in analyzing the damping effect of the UPFC and designing UPFC based stabilizer to improve power system oscillation stability. A comprehensive approach to the design of UPFC based stabilizer (power flow control, DC-voltage regulator and damping controller) is presented. In this case, the multi-machine power system with UPFC is studied and an example o...

  15. A silane-based polysilicon process

    Science.gov (United States)

    Grayson, P. E.; Jaffe, J.

    1986-01-01

    A silane based polysilicon process plant was constructed in Miami, Oklahoma. The processes included: the synthesis of crude silane gas, ultrapurification of the gas, and direct pyrolysis to product silicon. Features of the process provided for direct continuous operation from process feed to final product, without the requirement to store intermediates or even convert the silane to a liquid phase. Semiconductor product quality as analyzed internally was demonstrated by the first integrated operation of the plant.

  16. Solution processed transition metal oxide anode buffer layers for efficiency and stability enhancement of polymer solar cells

    Science.gov (United States)

    Ameen, M. Yoosuf; Shamjid, P.; Abhijith, T.; Reddy, V. S.

    2018-01-01

    Polymer solar cells were fabricated with solution-processed transition metal oxides, MoO3 and V2O5 as anode buffer layers (ABLs). The optimized device with V2O5 ABL exhibited considerably higher power conversion efficiency (PCE) compared to the devices based on MoO3 and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) ABLs. The space charge limited current measurements and impedance spectroscopy results of hole-only devices revealed that V2O5 provided a very low charge transfer resistance and high hole mobility, facilitating efficient hole transfer from the active layer to the ITO anode. More importantly, incorporation of V2O5 as ABL resulted in substantial improvement in device stability compared to MoO3 and PEDOT:PSS based devices. Unencapsulated PEDOT:PSS-based devices stored at a relative humidity of 45% have shown complete failure within 96 h. Whereas, MoO3 and V2O5 based devices stored in similar conditions retained 22% and 80% of their initial PCEs after 96 h. Significantly higher stability of the V2O5-based device is ascribed to the reduction in degradation of the anode/active layer interface, as evident from the electrical measurements.

  17. Effects of process conditions on chlorine generation and storage stability of electrolyzed deep ocean water.

    Science.gov (United States)

    Hsu, Guoo-Shyng Wang; Hsia, Chih-Wei; Hsu, Shun-Yao

    2015-12-01

    Electrolyzed water is a sustainable disinfectant, which can comply with food safety regulations and is environmentally friendly. We investigated the effects of platinum plating of electrode, electrode size, cell potential, and additional stirring on electrolysis properties of deep ocean water (DOW) and DOW concentration products. We also studied the relationships between quality properties of electrolyzed DOW and their storage stability. Results indicated that concentrating DOW to 1.7 times increased chlorine level in the electrolyzed DOW without affecting electric and current efficiencies of the electrolysis process. Increasing magnesium and potassium levels in DOW decreased chlorine level in the electrolyzed DOW as well as electric and current efficiencies of the electrolysis process. Additional stirring could not increase electrolysis efficiency of small electrolyzer. Large electrode, high electric potential and/or small electrolyzing cell increased chlorine production rate but decreased electric and current efficiencies. High electrolysis intensity decreased storage stability of the electrolyzed seawater and the effects of electrolysis on DOW gradually subsided in storage. DOW has similar electrolysis properties to surface seawater, but its purity and stability are better. Therefore, electrolyzed DOW should have better potential for applications on postharvest cleaning and disinfection of ready-to-eat fresh produce. Copyright © 2015. Published by Elsevier B.V.

  18. Differences in Pornography Use Among Couples: Associations with Satisfaction, Stability, and Relationship Processes.

    Science.gov (United States)

    Willoughby, Brian J; Carroll, Jason S; Busby, Dean M; Brown, Cameron C

    2016-01-01

    The present study utilized a sample of 1755 adult couples in heterosexual romantic relationships to examine how different patterns of pornography use between romantic partners may be associated with relationship outcomes. While pornography use has been generally associated with some negative and some positive couple outcomes, no study has yet explored how differences between partners may uniquely be associated with relationship well-being. Results suggested that greater discrepancies between partners in pornography use were related to less relationship satisfaction, less stability, less positive communication, and more relational aggression. Mediation analyses suggested that greater pornography use discrepancies were primarily associated with elevated levels of male relational aggression, lower female sexual desire, and less positive communication for both partners which then predicted lower relational satisfaction and stability for both partners. Results generally suggest that discrepancies in pornography use at the couple level are related to negative couple outcomes. Specifically, pornography differences may alter specific couple interaction processes which, in turn, may influence relationship satisfaction and stability. Implications for scholars and clinicians interested in how pornography use is associated with couple process are discussed.

  19. Structural Bases of Stability-Function Tradeoffs in Enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Beadle, Beth M; Shoichet, Brian K [NWU, MED

    2010-03-05

    The structures of enzymes reflect two tendencies that appear opposed. On one hand, they fold into compact, stable structures; on the other hand, they bind a ligand and catalyze a reaction. To be stable, enzymes fold to maximize favorable interactions, forming a tightly packed hydrophobic core, exposing hydrophilic groups, and optimizing intramolecular hydrogen-bonding. To be functional, enzymes carve out an active site for ligand binding, exposing hydrophobic surface area, clustering like charges, and providing unfulfilled hydrogen bond donors and acceptors. Using AmpC {beta}-lactamase, an enzyme that is well-characterized structurally and mechanistically, the relationship between enzyme stability and function was investigated by substituting key active-site residues and measuring the changes in stability and activity. Substitutions of catalytic residues Ser64, Lys67, Tyr150, Asn152, and Lys315 decrease the activity of the enzyme by 10{sup 3}-10{sup 5}-fold compared to wild-type. Concomitantly, many of these substitutions increase the stability of the enzyme significantly, by up to 4.7 kcal/mol. To determine the structural origins of stabilization, the crystal structures of four mutant enzymes were determined to between 1.90 {angstrom} and 1.50 {angstrom} resolution. These structures revealed several mechanisms by which stability was increased, including mimicry of the substrate by the substituted residue (S64D), relief of steric strain (S64G), relief of electrostatic strain (K67Q), and improved polar complementarity (N152H). These results suggest that the preorganization of functionality characteristic of active sites has come at a considerable cost to enzyme stability. In proteins of unknown function, the presence of such destabilized regions may indicate the presence of a binding site.

  20. Solution-processed, nanostructured hybrid solar cells with broad spectral sensitivity and stability.

    Science.gov (United States)

    Zhou, Renjia; Zheng, Ying; Qian, Lei; Yang, Yixing; Holloway, Paul H; Xue, Jiangeng

    2012-06-07

    Hybrid organic-inorganic solar cells, as an alternative to all-organic solar cells, have received significant attention for their potential advantages in combining the solution-processability and versatility of organic materials with high charge mobility and environmental stability of inorganic semiconductors. Here we report efficient and air-stable hybrid organic-inorganic solar cells with broad spectral sensitivity based on a low-gap polymer poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) and spherical CdSe nanoparticles. The solvents used for depositing the hybrid PCPDTBT:CdSe active layer were shown to strongly influence the film morphology, and subsequently the photovoltaic performance of the resulted solar cells. Appropriate post-deposition annealing of the hybrid film was also shown to improve the solar cell efficiency. The inclusion of a thin ZnO nanoparticle layer between the active layer and the metal cathode leads to a significant increase in device efficiency especially at long wavelengths, due to a combination of optical and electronic effects including more optimal light absorption in the active layer and elimination of unwanted hole leakage into the cathode. Overall, maximum power conversion efficiencies up to 3.7 ± 0.2% and spectral sensitivity extending above 800 nm were achieved in such PCPDTBT:CdSe nanosphere hybrid solar cells. Furthermore, the devices with a ZnO nanoparticle layer retained ∼70% of the original efficiency after storage under ambient laboratory conditions for over 60 days without any encapsulation.

  1. Microgrid Stability Controller Based on Adaptive Robust Total SMC

    DEFF Research Database (Denmark)

    Su, Xiaoling; Han, Minxiao; Guerrero, Josep M.

    2015-01-01

    This paper presents a microgrid stability controller (MSC) in order to provide existing DGs the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics....... The MSC provides fast dynamic response and robustness to the microgrid. When the system is operating in grid-connected mode, it is able to improve the controllability of the exchanged power between the microgrid and the utility grid, while smoothing DG’s output power. When the microgrid is operating...

  2. Voltage Stabilizer Based on SPWM technique Using Microcontroller

    Directory of Open Access Journals (Sweden)

    K. N. Tarchanidis

    2013-01-01

    Full Text Available This paper presents an application of the well known SPWM technique on a voltage stabilizer, using a microcontroller. The stabilizer is AC/DC/AC type. So, the system rectifies the input AC voltage to a suitable DC level and the intelligent control of an embedded microcontroller regulates the pulse width of the output voltage in order to produce through a filter a perfect sinusoidal AC voltage. The control program on the microcontroller has the ability to change the FET transistor firing in order to compensate any input voltage variation. The applied software using the microcontroller’s interrupts managed to achieve concurrency on the running program.

  3. Vitrification of F006 plating waste sludge by Reactive Additive Stabilization Process (RASP)

    International Nuclear Information System (INIS)

    Martin, H.L.; Jantzen, C.M.; Pickett, J.B.

    1994-01-01

    Solidification into glass of nickel-on-uranium plating wastewater treatment plant sludge (F006 Mixed Waste) has been demonstrated at the Savannah River She (SRS). Vitrification using high surface area additives, the Reactive Additive Stabilization Process (RASP), greatly enhanced the solubility and retention of heavy metals In glass. The bench-scale tests using RASP achieved 76 wt% waste loading In both soda-lime-silica and borosilicate glasses. The RASP has been Independently verified by a commercial waste management company, and a contract awarded to vitrify the approximately 500,000 gallons of stored waste sludge. The waste volume reduction of 89% will greatly reduce the disposal costs, and delisting of the glass waste is anticipated. This will be the world's first commercial-scale vitrification system used for environmental cleanup of Mixed Waste. Its stabilization and volume reduction abilities are expected to set standards for the future of the waste management Industry

  4. Polyethylene Glycol Based Graphene Aerogel Confined Phase Change Materials with High Thermal Stability.

    Science.gov (United States)

    Fu, Yang; Xiong, Weilai; Wang, Jianying; Li, Jinghua; Mei, Tao; Wang, Xianbao

    2018-05-01

    Polyethylene glycol (PEG) based graphene aerogel (GA) confined shaped-stabilized phase change materials (PCMs) are simply prepared by a one-step hydrothermal method. Three-dimensional GA inserted by PEG molecule chains, as a supporting material, obtained by reducing graphene oxide sheets, is used to keep their stabilized shape during a phase change process. The volume of GA is obviously expended after adding PEG, and only 9.8 wt% of GA make the composite achieve high energy efficiency without leakage during their phase change because of hydrogen bonding widely existing in the GA/PEG composites (GA-PCMs). The heat storage energy of GA-PCMs is 164.9 J/g, which is 90.2% of the phase change enthalpy of pure PEG. In addition, this composite inherits the natural thermal properties of graphene and thus shows enhanced thermal conductivity compared with pure PEG. This novel study provides an efficient way to fabricate shape-stabilized PCMs with a high content of PEG for thermal energy storage.

  5. Effect of Different Denture Base Materials and Changed Mouth Temperature on Dimensional Stability of Complete Dentures

    Science.gov (United States)

    Arafa, Khalid A. O.

    2016-01-01

    Background. Type of materials used in fabrication of denture base has an effect on dimension during denture base material processing and other factors related to clinical use. Objective. The study aims were to assess the dimensional stability including thermal changes of three different denture base materials. Methods. Ninety patients were selected to construct complete dentures with different denture base materials. They were randomly divided into three groups: group 1, patients with cobalt chrome metallic base; group 2, patients with heat curing acrylic resin fabricated by injection moulding technique; and group 3, patients with denture bases fabricated by conventional heat curing acrylic resin. The dimensional changes were assessed using digital caliper. Results. After the twelfth month, injection moulding acrylic resin had significantly the highest dimensional change followed by the conventional heat curing acrylic resin. There were no significant differences in the dimensions between the three types of denture base materials at normal mouth temperature, while, after hot tea drinking at 45°C, the dimensional change was significantly the highest in cobalt chrome metallic denture base group. Conclusion. Cobalt chrome metallic denture base has stable dimension compared to denture bases fabricated of acrylic resin but it was more affected by altered mouth temperature. The study was registered in the International Standard Randomized Controlled Trials Number (ISRCTN) registry with study ID (ISRCTN94238244). PMID:27143970

  6. Effect of Different Denture Base Materials and Changed Mouth Temperature on Dimensional Stability of Complete Dentures

    Directory of Open Access Journals (Sweden)

    Khalid A. O. Arafa

    2016-01-01

    Full Text Available Background. Type of materials used in fabrication of denture base has an effect on dimension during denture base material processing and other factors related to clinical use. Objective. The study aims were to assess the dimensional stability including thermal changes of three different denture base materials. Methods. Ninety patients were selected to construct complete dentures with different denture base materials. They were randomly divided into three groups: group 1, patients with cobalt chrome metallic base; group 2, patients with heat curing acrylic resin fabricated by injection moulding technique; and group 3, patients with denture bases fabricated by conventional heat curing acrylic resin. The dimensional changes were assessed using digital caliper. Results. After the twelfth month, injection moulding acrylic resin had significantly the highest dimensional change followed by the conventional heat curing acrylic resin. There were no significant differences in the dimensions between the three types of denture base materials at normal mouth temperature, while, after hot tea drinking at 45°C, the dimensional change was significantly the highest in cobalt chrome metallic denture base group. Conclusion. Cobalt chrome metallic denture base has stable dimension compared to denture bases fabricated of acrylic resin but it was more affected by altered mouth temperature. The study was registered in the International Standard Randomized Controlled Trials Number (ISRCTN registry with study ID (ISRCTN94238244.

  7. Effects of blood processing and sample storage on the stability of biotherapeutics and anti-drug antibodies.

    Science.gov (United States)

    Andisik, Matthew; DeStefano, Lisa; Stefan, Colin; Gathani, Meghna; Laurino, Kevin; Lai, Vicky Ch; Rajadhyaksha, Manoj; Torri, Albert; Shao, Weiping

    2015-01-01

    Pre-analytical factors such as sample processing, handling or storage could affect the stability of biotherapeutics and anti-drug antibodies in clinical samples, potentially impacting the pharmacokinetic and immunogenicity assessments. We used sarilumab, a fully human IgG1 monoclonal antibody, and evaluated the stability of sarilumab (both functional and bound forms) and anti-sarilumab antibodies in blood samples during serum collection and the impact of various processing conditions on the analyte stability in serum for long-term storage. We also assessed the incurred sample stability of these analytes in samples from clinical studies. Assessment of analyte stability can provide relevant information about sample stability under different pre-analytical conditions and improve the confidence in the validity of bioanalytical data generated.

  8. Copper stressed anaerobic fermentation: biogas properties, process stability, biodegradation and enzyme responses.

    Science.gov (United States)

    Hao, He; Tian, Yonglan; Zhang, Huayong; Chai, Yang

    2017-12-01

    The effect of copper (added as CuCl 2 ) on the anaerobic co-digestion of Phragmites straw and cow dung was studied in pilot experiments by investigating the biogas properties, process stability, substrate degradation and enzyme activities at different stages of mesophilic fermentation. The results showed that 30 and 100 mg/L Cu 2+ addition increased the cumulative biogas yields by up to 43.62 and 20.77% respectively, and brought forward the daily biogas yield peak, while 500 mg/L Cu 2+ addition inhibited biogas production. Meanwhile, the CH 4 content in the 30 and 100 mg/L Cu 2+ -added groups was higher than that in the control group. Higher pH values (close to pH 7) and lower oxidation-reduction potential (ORP) values in the Cu 2+ -added groups after the 8th day indicated better process stability compared to the control group. In the presence of Cu 2+ , the degradation of volatile fatty acids (VFAs) and other organic molecules (represented by chemical oxygen demand, COD) generated from hydrolysis was enhanced, and the ammonia nitrogen (NH 4 + -N) concentrations were more stable than in the control group. The contents of lignin and hemicellulose in the substrate declined in the Cu 2+ -added groups while the cellulose contents did not. Neither the cellulase nor the coenzyme F 420 activities could determine the biogas producing efficiency. Taking the whole fermentation process into account, the promoting effect of Cu 2+ addition on biogas yields was mainly attributable to better process stability, the enhanced degradation of lignin and hemicellulose, the transformation of intermediates into VFA, and the generation of CH 4 from VFA.

  9. Lyapunov Based Estimation of Flight Stability Boundary under Icing Conditions

    Directory of Open Access Journals (Sweden)

    Binbin Pei

    2017-01-01

    Full Text Available Current fight boundary of the envelope protection in icing conditions is usually defined by the critical values of state parameters; however, such method does not take the interrelationship of each parameter and the effect of the external disturbance into consideration. This paper proposes constructing the stability boundary of the aircraft in icing conditions through analyzing the region of attraction (ROA around the equilibrium point. Nonlinear icing effect model is proposed according to existing wind tunnel test results. On this basis, the iced polynomial short period model can be deduced further to obtain the stability boundary under icing conditions using ROA analysis. Simulation results for a series of icing severity demonstrate that, regardless of the icing severity, the boundary of the calculated ROA can be treated as an estimation of the stability boundary around an equilibrium point. The proposed methodology is believed to be a promising way for ROA analysis and stability boundary construction of the aircraft in icing conditions, and it will provide theoretical support for multiple boundary protection of icing tolerant flight.

  10. Virtual Impedance Based Stability Improvement for DC Microgrids with Constant Power Loads

    DEFF Research Database (Denmark)

    Lu, Xiaonan; Sun, Kai; Huang, Lipei

    2014-01-01

    DC microgrid provides an efficient way to integrate different kinds of renewable energy sources with DC couplings. In this paper, in order to improve the stability of DC microgrids with constant power loads (CPLs), a virtual impedance based method is proposed. The CPLs have inherent instability...... issues induced by negative incremental impedances. This negative impedance makes the system poorly damped and the stability is thereby degraded. To enhance the system stability, virtual impedance based stabilizer comprised of series-connected inductance and resistance is employed. In particular, two...

  11. CIM5 Phase III base process development results

    International Nuclear Information System (INIS)

    Witt, D.C.

    2000-01-01

    Integrated Demonstration Runs for the Am/Cm vitrification process were initiated in the Coupled 5-inch Cylindrical Induction Melter (CIM5) on 11/30/98 and completed on 12/9/98. Four successful runs at 60 wt% lanthanide loading were completed which met or exceeded all established criteria. The operating parameters used in these runs established the base conditions for the 5-inch Cylindrical Induction Melter (CIM5) process and were summarized in the 5-inch CIM design basis, SRT-AMC-99-OO01. (1) In subsequent tests, a total of fourteen CIM5 runs were performed using various power inputs, ramp rates and target temperatures to define the preferred processing conditions (2) Process stability and process flexibility were the key criteria used in assessing the results for each run. A preferred set of operating parameters was defined for the CIM5 batch process and these conditions were used to generate a pre-programmed, automatic processing cycle that was used for the last six CIM.5 runs (3) These operational tests were successfully completed in the January-February time frame and were summarized in SRT-AMC-99-00584. The recommended set of operating conditions defined in Runs No.1 through No.14 was used as the starting point for further pilot system runs to determine the robustness of the process, evaluate a bubbler, and investigate off-normal conditions. CIM5 Phase III Runs No.15 through No.60 were conducted utilizing the pre-programmed, automatic processing cycle to investigate system performance. This report summarizes the results of these tests and provides a recommendation for the base process as well as a processing modification for minimizing volume expansions if americium and/or curium are subject to a thermal reduction reaction like cerium. This document summarizes the results of the base process development tests conducted in the Am/Cm Pilot Facility located in Building 672-T

  12. M-X Basing Area Analysis Process

    National Research Council Canada - National Science Library

    1980-01-01

    ... or unreasonable basing areas for the M-X missile in multiple protective structures (MPS). The process began in January 1977 with criteria involving geotechnical, cultural, safety and other concerns...

  13. Frequency scanning-based stability analysis method for grid-connected inverter system

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    This paper proposes a frequency scanning-based impedance analysis for stability assessment of grid-connected inverter system, which is able to perform stability assessment without using system mathematical models and inherit the superior feature of impedance-based stability criterion with conside......This paper proposes a frequency scanning-based impedance analysis for stability assessment of grid-connected inverter system, which is able to perform stability assessment without using system mathematical models and inherit the superior feature of impedance-based stability criterion...... with consideration of the inverter nonlinearities. Small current disturbance is injected into grid-connected inverter system in a particular frequency range, and the impedance is computed according to the harmonic-frequency response using Fourier analysis, and then the stability is predicted on the basis...... of the impedance stability criterion. The stability issues of grid-connected inverters with grid-current feedback and the converter-current feedback are addressed using the proposed method. The results obtained from simulation and experiments validate the effectiveness of the method. The frequency scanning...

  14. Temporal Information Processing and Stability Analysis of the MHSN Neuron Model in DDF

    Directory of Open Access Journals (Sweden)

    Saket Kumar Choudhary

    2016-12-01

    Full Text Available Implementation of a neuron like information processing structure at hardware level is a burning research problem. In this article, we analyze the modified hybrid spiking neuron model (the MHSN model in distributed delay framework (DDF for hardware level implementation point of view. We investigate its temporal information processing capability in term of inter-spike-interval (ISI distribution. We also perform the stability analysis of the MHSN model, in which, we compute nullclines, steady state solution, eigenvalues corresponding the MHSN model. During phase plane analysis, we notice that the MHSN model generates limit cycle oscillations which is an important phenomenon in many biological processes. Qualitative behavior of these limit cycle does not changes due to the variation in applied input stimulus, however, delay effect the spiking activity and duration of cycle get altered.

  15. Research results on productivity stabilization by ultrasonic camera (plant with membrane ceramic elements during vine processing

    Directory of Open Access Journals (Sweden)

    V. T. Antufyev

    2016-01-01

    Full Text Available The article describes solutions to the problems of declining productivity of ceramic membrane elements for wine processing on the final manufacturing phase. A relative stabilization of filtration velocity, venting efficiency and wine lightening were experimentally confirmed during contacts with oscillation waves of ultrasonic transmitter on the ceramic filter. Which significantly reduced the cost of various preservatives to increase periods storage. To study the processes of wine processing by the proposed method it was made an experimental installation on the basis of pilot machine MRp-1/2 for bottling of quiet liquids and an ultrasonic device "Volna– M" UZTA-1/22-OM with a firmly, waveguide which transmits sound, fixed filter frame on the ultrasound emitter. To stabilize the performance of ultrasonic units with ceramic membrane elements without quality deterioration of wines it was empirically determined rational parameters of power of ultrasound input and pressure in the system. The given derived dependencies and graphs allow to define the time of relatively stable operating filter regime. It was revealed a significant cost reduction on filtration, as it allows escape from the contamination of the product by various preservatives, and increasing of storage duration in a sealed container during aseptic filling without a thermal sterilization. Ultrasonic emitter contact by superposition wave vibrations on the ceramic filter increases not only the efficiency of gas removal, but also improves the organoleptic characteristics, stabilizes the filters, improves their productivity. Gas removal creates unfavorable conditions for development of the yeast, which in turn increases the shelf life of semisweet wine.

  16. The temporal stability and predictive validity of affect-based and cognition-based intentions.

    Science.gov (United States)

    Keer, Mario; Conner, Mark; Van den Putte, Bas; Neijens, Peter

    2014-06-01

    Recent research has revealed individual differences in the extent to which people base their intentions on affect and cognition. Two studies are presented that assess whether such differences predict the strength of individuals' intention-behaviour relationships. Participants completed measures of affect, cognition, intention, and behaviour regarding a range of health behaviours. Study 1 (N = 300) found that the strength of the intention-behaviour relationship was significantly related to the extent to which individuals based their intentions on affect, but not to the extent they based them on cognition. Study 2 (N = 387) replicated the findings of the first study. In addition, Study 2 revealed that intention stability mediated the relationship between the degree people based their intentions on affect and the strength of the intention-behaviour relationship. Thus, individuals who base their intentions strongly on affect have more stable intentions, and are therefore more likely to enact them. © 2013 The British Psychological Society.

  17. Effect of thermal and high pressure processing on stability of betalain extracted from red beet stalks.

    Science.gov (United States)

    Dos Santos, Cláudia Destro; Ismail, Marliya; Cassini, Aline Schilling; Marczak, Ligia Damasceno Ferreira; Tessaro, Isabel Cristina; Farid, Mohammed

    2018-02-01

    Red beet stalks are a potential source of betalain, but their pigments are not widely used because of their instability. In the present work, the applicability of high pressure processing (HPP) and high temperature short time (HTST) thermal treatment was investigated to improve betalain stability in extracts with low and high concentrations. The HPP was applied at 6000 bar for 10, 20 and 30 min and HTST treatment was applied at 75.7 °C for 80 s, 81.1 °C for 100 s and 85.7 °C for 120 s, HPP treatment did not show any improvement in the betalain stability. In turn, the degradation rate of the control and the HTST thermal treatment at 85.7 °C for 120 s of the sample with high initial betalain concentration were 1.2 and 0.4 mg of betanin/100 ml of extract per day respectively. Among the treatments studied, HTST was considered the most suitable to maintain betalain stability from red beet stalks.

  18. Effect of ohmic heating processing conditions on color stability of fungal pigments.

    Science.gov (United States)

    Aguilar-Machado, Diederich; Morales-Oyervides, Lourdes; Contreras-Esquivel, Juan C; Aguilar, Cristóbal; Méndez-Zavala, Alejandro; Raso, Javier; Montañez, Julio

    2017-06-01

    The aim of this work was to analyze the effect of ohmic heating processing conditions on the color stability of a red pigment extract produced by Penicillium purpurogenum GH2 suspended in a buffer solution (pH 6) and in a beverage model system (pH 4). Color stability of pigmented extract was evaluated in the range of 60-90 ℃. The degradation pattern of pigments was well described by the first-order (fractional conversion) and Bigelow model. Degradation rate constants ranged between 0.009 and 0.088 min -1 in systems evaluated. Significant differences in the rate constant values of the ohmic heating-treated samples in comparison with conventional thermal treatment suggested a possible effect of the oscillating electric field generated during ohmic heating. The thermodynamic analysis also indicated differences in the color degradation mechanism during ohmic heating specifically when the pigment was suspended in the beverage model system. In general, red pigments produced by P. purpurogenum GH2 presented good thermal stability under the range of the evaluated experimental conditions, showing potential future applications in pasteurized food matrices using ohmic heating treatment.

  19. Olive-oil nanocapsules stabilized by HSA: influence of processing variables on particle properties

    Science.gov (United States)

    Molina-Bolívar, J. A.; Galisteo-González, F.

    2015-10-01

    Liquid lipid nanocapsules (LLN) are considered to be promising drug carriers in the medical field. The size and the surface charge of these nanocarriers are of major importance, affecting their bioavailability and the in vivo behaviour after intravenous injection. This research provides a comprehensive study on the preparation of olive-oil nanocapsules stabilized with a human serum albumin shell (HSA). LLN were prepared by modified solvent-displacement method. Numerous experimental variables were examined in order to characterize their impact on LLN size, distribution, and electrophoretic mobility. Physicochemical parameters of LLN were controlled by adjusting the nanodroplet stabilizing shell of adsorbed protein molecules, which was affected by the oil:HSA ratio, pH, and ionic strength of aqueous medium. The stronger the repulsion between adsorbed HSA molecules, the smaller and more monodisperse the particles proved. Other process parameters, including the ethanol:acetone ratio, organic:aqueous phase ratio, speed of organic-phase injection, and stirring rate were examined to achieve optimum preparation conditions. LLN produced by our standardized formulation were in the range of 170-175 nm with low polydispersity index (olive-oil nanocapsules was achieved (90 %). Encapsulation of curcumin into LLN had a stabilizing effect with respect to drug photodecomposition compared to that of the free molecule in solution.

  20. Finite-Time Stabilization and Adaptive Control of Memristor-Based Delayed Neural Networks.

    Science.gov (United States)

    Wang, Leimin; Shen, Yi; Zhang, Guodong

    Finite-time stability problem has been a hot topic in control and system engineering. This paper deals with the finite-time stabilization issue of memristor-based delayed neural networks (MDNNs) via two control approaches. First, in order to realize the stabilization of MDNNs in finite time, a delayed state feedback controller is proposed. Then, a novel adaptive strategy is applied to the delayed controller, and finite-time stabilization of MDNNs can also be achieved by using the adaptive control law. Some easily verified algebraic criteria are derived to ensure the stabilization of MDNNs in finite time, and the estimation of the settling time functional is given. Moreover, several finite-time stability results as our special cases for both memristor-based neural networks (MNNs) without delays and neural networks are given. Finally, three examples are provided for the illustration of the theoretical results.Finite-time stability problem has been a hot topic in control and system engineering. This paper deals with the finite-time stabilization issue of memristor-based delayed neural networks (MDNNs) via two control approaches. First, in order to realize the stabilization of MDNNs in finite time, a delayed state feedback controller is proposed. Then, a novel adaptive strategy is applied to the delayed controller, and finite-time stabilization of MDNNs can also be achieved by using the adaptive control law. Some easily verified algebraic criteria are derived to ensure the stabilization of MDNNs in finite time, and the estimation of the settling time functional is given. Moreover, several finite-time stability results as our special cases for both memristor-based neural networks (MNNs) without delays and neural networks are given. Finally, three examples are provided for the illustration of the theoretical results.

  1. Design of Power System Stabilizer Based on Sliding Mode Control Theory for Multi- Machine Power System

    OpenAIRE

    Hossein Shahinzadeh; Ladan Darougaran; Ebrahim Jalili Sani; Hamed Yavari; Mahdi Mozaffari Legha

    2012-01-01

    This paper present a new method for design of power system stabilizer (PSS) based on sliding mode control (SMC) technique. The control objective is to enhance stability and improve the dynamic response of the multi-machine power system. In order to test effectiveness of the proposed scheme, simulation will be carried out to analyze the small signal stability characteristics of the system about the steady state operating condition following the change in reference mechanic...

  2. Power System Stabilizer Design Based on a Particle Swarm Optimization Multiobjective Function Implemented Under Graphical Interface

    OpenAIRE

    Ghouraf Djamel Eddine

    2016-01-01

    Power system stability considered a necessary condition for normal functioning of an electrical network. The role of regulation and control systems is to ensure that stability by determining the essential elements that influence it. This paper proposes a Particle Swarm Optimization (PSO) based multiobjective function to tuning optimal parameters of Power System Stabilizer (PSS); this later is used as auxiliary to generator excitation system in order to damp electro mechanicals oscillations of...

  3. Stability in Bank Income through Fee-based Activities

    Directory of Open Access Journals (Sweden)

    R. K. Uppal

    2010-12-01

    Full Text Available This paper is an attempt to study the trends in non-interest income which is a vital source of stability in bank income. For this, the study takes some parameters like interest and non-interest income as a percentage to total income, share of non-interest income components like exchange & brokerage, sale in investment and exchange transaction. On the basis of these parameters the study concludes that interest income is continuously declining due to deregulation in interest rates and non-interest income is rising. Among the non-interest income components, commodity exchange & brokerage witnessed a large share while exchange transaction witnessed a meager part. The paper also gives some ways and means to bring stability in the total income.

  4. Real-Time Stability Assessment based on Synchrophasors

    DEFF Research Database (Denmark)

    Jóhannsson, Hjörtur; Garcia-Valle, Rodrigo; Weckesser, Johannes Tilman Gabriel

    2011-01-01

    eventually cause in very sharp decline in system voltages at intermediate locations between the two groups as the angular separation approaches 180◦. In order to receive an early warning for the occurrence of such type of blackouts, the boundaries of the system generators aperiodic small-signal stability...... generator can inject into the system. The limits for maximum injectable power represent the boundary for aperiodic small signal stability. The concept of the proposed method is tested on two different systems. The results show that the method is capable of accurately detecting when a given machine crosses......In this paper, an overview is provided of a new method that in real-time provides an early warning for an emerging blackout that are characterized by a slowly increasing angular separation between sub-groups of system generators. Such angular separation between subgroups of generators can...

  5. Web-Based Distributed XML Query Processing

    NARCIS (Netherlands)

    Smiljanic, M.; Feng, L.; Jonker, Willem; Blanken, Henk; Grabs, T.; Schek, H-J.; Schenkel, R.; Weikum, G.

    2003-01-01

    Web-based distributed XML query processing has gained in importance in recent years due to the widespread popularity of XML on the Web. Unlike centralized and tightly coupled distributed systems, Web-based distributed database systems are highly unpredictable and uncontrollable, with a rather

  6. Digital Signal Processing Based Biotelemetry Receivers

    Science.gov (United States)

    Singh, Avtar; Hines, John; Somps, Chris

    1997-01-01

    This is an attempt to develop a biotelemetry receiver using digital signal processing technology and techniques. The receiver developed in this work is based on recovering signals that have been encoded using either Pulse Position Modulation (PPM) or Pulse Code Modulation (PCM) technique. A prototype has been developed using state-of-the-art digital signal processing technology. A Printed Circuit Board (PCB) is being developed based on the technique and technology described here. This board is intended to be used in the UCSF Fetal Monitoring system developed at NASA. The board is capable of handling a variety of PPM and PCM signals encoding signals such as ECG, temperature, and pressure. A signal processing program has also been developed to analyze the received ECG signal to determine heart rate. This system provides a base for using digital signal processing in biotelemetry receivers and other similar applications.

  7. Process-based software project management

    CERN Document Server

    Goodman, F Alan

    2006-01-01

    Not connecting software project management (SPM) to actual, real-world development processes can lead to a complete divorcing of SPM to software engineering that can undermine any successful software project. By explaining how a layered process architectural model improves operational efficiency, Process-Based Software Project Management outlines a new method that is more effective than the traditional method when dealing with SPM. With a clear and easy-to-read approach, the book discusses the benefits of an integrated project management-process management connection. The described tight coup

  8. Study and Application on Stability Classification of Tunnel Surrounding Rock Based on Uncertainty Measure Theory

    Directory of Open Access Journals (Sweden)

    Hujun He

    2014-01-01

    Full Text Available Based on uncertainty measure theory, a stability classification and order-arranging model of surrounding rock was established. Considering the practical engineering geologic condition, 5 factors that influence surrounding rock stability were taken into account and uncertainty measure function was obtained based on the in situ data. In this model, uncertainty influence factors were analyzed quantitatively and qualitatively based on the real situation; the weight of index was given based on information entropy theory; surrounding rock stability level was judged based on credible degree recognition criterion; and surrounding rock was ordered based on order-arranging criterion. Furthermore, this model was employed to evaluate 5 sections surrounding rock in Dongshan tunnel of Huainan. The results show that uncertainty measure method is reasonable and can have significance for surrounding rock stability evaluation in the future.

  9. Stability and Activity of Doped Transition Metal Zeolites in the Hydrothermal Processing

    Energy Technology Data Exchange (ETDEWEB)

    Robin, Thomas François, E-mail: thomas.cognac@gmail.com; Ross, Andrew B.; Lea-Langton, Amanda R.; Jones, Jenny M. [School of Chemical and Process Engineering, University of Leeds, Leeds (United Kingdom)

    2015-12-14

    This study investigates the stability and activity of HZSM-5 doped with metals such as molybdenum, nickel, copper, and iron under hydrothermal conditions used for the direct liquefaction of microalgae. Catalysts have been prepared by ion-exchange techniques, and MoZSM-5 was also prepared by wet incipient impregnation for comparison. Hydrothermal liquefaction is considered a potential route to convert microalgae into a sustainable fuel. One of the drawbacks of this process is that the bio-crude produced contains significant levels of nitrogen and oxygen compounds that have an impact on the physical and chemical properties of the fuel. Heterogeneous catalysts have been shown to improve the quality of the bio-crude by reducing nitrogen and oxygen contents. Zeolites, such as HZSM-5, are strong candidates due to their low cost compared to noble metal catalysts, but their stability and activity under hydrothermal conditions are not well understood. The stability of the catalysts has been determined under hydrothermal conditions at 350°C. Catalysts have been characterized before and after treatment using X-ray diffraction, BET physisorption, and scanning transmission electronic microscopy. Metal leaching was determined by the analysis of the water phase following the hydrothermal treatment. The inserted cation following ion-exchange can influence the physical properties of HZSM-5, for example, molybdenum improves the crystallinity of the zeolite. In general, metal-doped zeolites were relatively stable in subcritical water. The activity of the catalysts for processing lipids, protein, and microalgae has been assessed. Four feedstocks were selected: sunflower oil, soya proteins, Chlorella, and Pseudochoricystis ellipsoidea. The catalysts exhibited greater activity toward converting lipids, for example, MoZSM-5 enhanced the formation of aromatic compounds. NiZSM-5 and CuZSM-5 were observed to be more efficient for deoxygenation.

  10. Design values of resilient modulus of stabilized and non-stabilized base.

    Science.gov (United States)

    2010-10-01

    The primary objective of this research study is to determine design value ranges for typical base materials, as allowed by LADOTD specifications, through laboratory tests with respect to resilient modulus and other parameters used by pavement design ...

  11. An active damper for stabilizing power electronics-based AC systems

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Liserre, Marco

    2013-01-01

    The mutual interactions between the parallel grid-connected converters coupled through the grid impedance tend to result in a number of stability and power quality challenges. To address them, this paper proposes an active damper concept based on a low-power, high-bandwidth power converter......-connected converters are carried out. The results validate the stabilizing performance of the active damper....

  12. Synthesis and stability of Br2, ICl and IBr intercalated pitch-based graphite fibers

    Science.gov (United States)

    Wessbecher, Dorothy E.; Forsman, William C.; Gaier, James R.

    1988-01-01

    The intercalation of halogens in pitch-based fiber is studied as well as the stability of the resultant intercalation compounds. It is found that IBr intercalates P-100 to yield a high-sigma GIC with attractive stability properties. During ICl intercalation, the presence of O2 interferes with the reaction and necessitates a higher threshold pressure for intercalation.

  13. A solidification/stabilization process for wastewater treatment sludge from a primary copper smelter

    Directory of Open Access Journals (Sweden)

    Ivšić-Bajčeta Dragana

    2013-01-01

    Full Text Available Wastewater treatment sludge from primary copper smelter is characterized as hazardous waste that requires treatment prior disposal due to significant amount of heavy metals and arsenic. The aim of the presented study was to investigate the feasibility and the effectiveness of solidification/stabilization process of the sludge using fly ash and lime as binders. The effectiveness of the process was evaluated by Unconfined Compressive Strength (UCS testing, leaching tests (EN 12457-4 and Toxicity Characteristic Leaching Procedure (TCLP and Acid Neutralization Capacity (ANC test. All samples reached target UCS of 0.35 MPa. Calcium to silicon concentration ratio (cCa/cSi, determined by X-Ray Fluorescence (XRF analysis, was identified as main factor governing strength development. Inductively coupled plasma-optical emission spectrometry (ICP-OES analyses of solutions after leaching tests showed excellent stabilization of Cu, Ni, Pb and Zn (above 99 % and arsenic (above 90 % in samples with high Ca(OH2 content. Results of ANC test indicated that buffering capacity of solidified material linearly depended on Ca concentration in FA and lime. Sample with 20 % of binder heaving 50 % of FA and 50 % of lime met all requirements to be safely disposed. [Projekat Ministarstva nauke Republike Srbije, br. 34033

  14. Processing and stabilization of Aloe Vera leaf gel by adding chemical and natural preservatives

    Directory of Open Access Journals (Sweden)

    N. Nazemi

    2017-11-01

    Full Text Available Background and objectives: Aloe vera has been used as a medicinal herb for thousands of years. Aloe vera leaves can be separated into latex and gel which have biological effects. Aloe gel is a potent source of polysaccharides. When the gel is exposed to air, it quickly decomposes and decays and loses most of its biological activity. There are various processing techniques for sterilizing and stabilizing the gel. The aim of this study was to improve stabilization of the gel by adding some chemical and natural preservatives. Methods: The gel was obtained from Aloe vera leaves and after some processing chemical and natural preservatives were added. Chemicals included citric acid, ascorbic acid, vitamin E and potassium sorbate while natural preservatives were two essential oils derived from Cinnamomum zeylanicum and Eugenia caryophyllata. All these operations were performed under sterile conditions and they were evaluated at different temperatures and times. Appearance and taste changes of gel were studied organoleptic. Microbiological tests and some physical assays such as pH, refractometry and viscosity properties as well as determination of total sugars were measured. NMR and FT-IR analyses were performed for determining the quality of samples. Results: After data analyzing, the results showed that the samples formulated with chemical additives together with essential oils were more suitable and stable compared to the control samples after 90 days and the effective ingredient acemannan, remained stable. Conclusion: The stable gel can be considered for therapeutic properties and be used for edible and medicinal purposes.

  15. Prediction of the stability of BWR reactors during the start-up process

    International Nuclear Information System (INIS)

    Ruiz E, J.A.; Castillo D, R.; Blazquez M, J.B.

    2004-01-01

    The Boiling Water Reactors (BWR) are susceptible of uncertainties of power when they are operated to low flows of coolant (W) and high powers (P), being presented this situation mainly in the start-up process. The start-up process could be made but sure if the operator knew the value of the stability index Decay reason (Dr) before going up power and therefore to guarantee the stability. The power and the flow are constantly measures, the index Dr could also be considered its value in real time. The index Dr depends on the power, flow and many other values, such as, the distribution of the flow axial and radial neutronic, the temperature of the feeding water, the fraction of holes and other thermohydraulic and nuclear parameters. A simple relationship of Dr is derived leaving of the pattern reduced of March-Leuba, where three independent variables are had that are the power, the flow and a parameter that it contains the rest of the phenomenology, that is to say all the other quantities that affect the value of Dr. This relationship developed work presently and verified its prediction with data of start-up of commercial reactors could be used for the design of a practical procedure practice of start-up, what would support to the operator to prevent this type of events of uncertainty. (Author)

  16. Development process for the stabilization of incinerator bottom ash and sizing baghouse dust material

    International Nuclear Information System (INIS)

    Hunt, L.F.; Boehmer, A.M.

    1987-04-01

    EG ampersand G Idaho Inc. has initiated a program to develop safe, efficient, cost-effective treatment methods for the stabilization and subsequent disposal of some of the hazardous and mixed wastes generated at the Idaho National Engineering Laboratory (INEL). Lab-scale testing has shown that Extraction Procedure (EP) toxic wastes can be successfully stabilized by solidification, using various binders to produce nontoxic, stable waste forms for safe, long-term disposal. The purpose of this report is to present the results of drum-scale testing of WERF incinerator bottom ash and WERF sizing baghouse dust. The drum-scale test program was conducted to determine if a production procedure that would produce a waste form which was suitable for disposal as a low-level radioactive waste could be developed. The use of 71-gallon square drums for solidification processing were also evaluated. During the test program, eleven drums of ash material were solidified. All of the samples from all of the drums passed the EPA leach test criteria. Although there is a distinct weight addition associated with the solidification process, there is no relative volume increase. 4 refs., 6 figs., 8 tabs

  17. Data on blueberry peroxidase kinetic characterization and stability towards thermal and high pressure processing

    Directory of Open Access Journals (Sweden)

    Netsanet Shiferaw Terefe

    2017-08-01

    Full Text Available The data presented in this article are related to a research article entitled ‘Thermal and high pressure inactivation kinetics of blueberry peroxidase’ (Terefe et al., 2017 [1]. In this article, we report original data on the activity of partially purified blueberry peroxidase at different concentrations of hydrogen peroxide and phenlylenediamine as substrates and the effects of thermal and high pressure processing on the activity of the enzyme. Data on the stability of the enzyme during thermal (at temperatures ranging from 40 to 80 °C and combined thermal-high pressure processing (100–690 MPa, 30–90 °C are included in this report. The data are presented in this format in order to facilitate comparison with data from other researchers and allow statistical analyses and modeling by others in the field.

  18. Polyelectrolyte Brush-Grafted Polydopamine-Based Catalysts with Enhanced Catalytic Activity and Stability.

    Science.gov (United States)

    Kaang, Byung Kwon; Han, Nara; Lee, Ha-Jin; Choi, Won San

    2018-01-10

    Three types of surface treatments, namely, polyethyleneimine (PEI) coating, short PEI (S-PEI) grafting, and long PEI (L-PEI) grafting, were performed on polydopamine (Pdop)-based catalysts to enhance their catalytic activity and stability. Brush-grafted catalysts were prepared by the stepwise synthesis of Au and short (or long) PEI brushes on Pdop particles (PdopP/Au/S- or L-PEI grafting). PEI-coated Pdop-based catalysts (PdopP/Au/PEI coating) were also prepared as non-brush-grafted catalysts. Among the surface-treated PdopP/Au catalysts, the brush-grafted catalysts (S-PEI and L-PEI grafting) exhibited excellent and stable catalytic performance because the brush grafting enabled the protection of the catalysts against harsh conditions, effective transfer of reactants to the catalysts, and confinement of reactants around the catalysts. The brush-grafted catalysts could also more effectively decompose larger dyes than the non-brush-grafted catalysts. The process-to-effectiveness of PEI coating is the best because the release of Pdop from PdopP/Au was moderately inhibited by the presence of only one layer of PEI coating on the PdopP/Au. Thus, this approach could be an alternative method to enhance the stability of PdopP/Au catalysts.

  19. Research on Stabilization Properties of Inductive-Capacitive Transducers Based on Hybrid Electromagnetic Elements

    Science.gov (United States)

    Konesev, S. G.; Khazieva, R. T.; Kirllov, R. V.; Konev, A. A.

    2017-01-01

    Some electrical consumers (the charge system of storage capacitor, powerful pulse generators, electrothermal systems, gas-discharge lamps, electric ovens, plasma torches) require constant power consumption, while their resistance changes in the limited range. Current stabilization systems (CSS) with inductive-capacitive transducers (ICT) provide constant power, when the load resistance changes over a wide range and increaseы the efficiency of high-power loads’ power supplies. ICT elements are selected according to the maximum load, which leads to exceeding a predetermined value of capacity. The paper suggests carrying load power by the ICT based on multifunction integrated electromagnetic components (MIEC) to reduce the predetermined capacity of ICT elements and CSS weights and dimensions. The authors developed and patented ICT based on MIEC that reduces the CSS weights and dimensions by reducing components number with the possibility of device’s electric energy transformation and resonance frequency changing. An ICT mathematical model was produced. The model determines the width of the load stabilization range. Electromagnetic processes study model was built with the MIEC integral parameters (full inductance of the electrical lead, total capacity, current of electrical lead). It shows independence of the load current from the load resistance for different ways of MIEC connection.

  20. An empirically based steady state friction law and implications for fault stability.

    Science.gov (United States)

    Spagnuolo, E; Nielsen, S; Violay, M; Di Toro, G

    2016-04-16

    Empirically based rate-and-state friction laws (RSFLs) have been proposed to model the dependence of friction forces with slip and time. The relevance of the RSFL for earthquake mechanics is that few constitutive parameters define critical conditions for fault stability (i.e., critical stiffness and frictional fault behavior). However, the RSFLs were determined from experiments conducted at subseismic slip rates ( V   0.1 m/s) remains questionable on the basis of the experimental evidence of (1) large dynamic weakening and (2) activation of particular fault lubrication processes at seismic slip rates. Here we propose a modified RSFL (MFL) based on the review of a large published and unpublished data set of rock friction experiments performed with different testing machines. The MFL, valid at steady state conditions from subseismic to seismic slip rates (0.1 µm/s fault frictional stability with implications for slip event styles and relevance for models of seismic rupture nucleation, propagation, and arrest.

  1. Object-based neglect in number processing

    Science.gov (United States)

    2013-01-01

    Recent evidence suggests that neglect patients seem to have particular problems representing relatively smaller numbers corresponding to the left part of the mental number line. However, while this indicates space-based neglect for representational number space little is known about whether and - if so - how object-based neglect influences number processing. To evaluate influences of object-based neglect in numerical cognition, a group of neglect patients and two control groups had to compare two-digit numbers to an internally represented standard. Conceptualizing two-digit numbers as objects of which the left part (i.e., the tens digit should be specifically neglected) we were able to evaluate object-based neglect for number magnitude processing. Object-based neglect was indicated by a larger unit-decade compatibility effect actually reflecting impaired processing of the leftward tens digits. Additionally, faster processing of within- as compared to between-decade items provided further evidence suggesting particular difficulties in integrating tens and units into the place-value structure of the Arabic number system. In summary, the present study indicates that, in addition to the spatial representation of number magnitude, also the processing of place-value information of multi-digit numbers seems specifically impaired in neglect patients. PMID:23343126

  2. Problems of modeling and optimal stabilization of the gas-lift process

    Science.gov (United States)

    Aliev, F. A.; Il'yasov, M. Kh.; Nuriev, N. B.

    2010-11-01

    The problems of motion of fluids, gases and gas-liquid mixtures in pipes related to gas-lift oil recovery are mathematically formulated as systems of nonlinear hyperbolic partial differential equations. Optimal-control problems are posed based on the proposed models and some real assumptions. These problems can be used to design programmed paths and controls, which underlie the controllers that stabilize the pressure or volume of injected gas. That the mathematical models agree with available field and laboratory data is demonstrated by examples

  3. Stability of black holes based on horizon thermodynamics

    Directory of Open Access Journals (Sweden)

    Meng-Sen Ma

    2015-12-01

    Full Text Available On the basis of horizon thermodynamics we study the thermodynamic stability of black holes constructed in general relativity and Gauss–Bonnet gravity. In the framework of horizon thermodynamics there are only five thermodynamic variables E, P, V, T, S. It is not necessary to consider concrete matter fields, which may contribute to the pressure of black hole thermodynamic system. In non-vacuum cases, we can derive the equation of state, P=P(V,T. According to the requirements of stable equilibrium in conventional thermodynamics, we start from these thermodynamic variables to calculate the heat capacity at constant pressure and Gibbs free energy and analyze the local and global thermodynamic stability of black holes. It is shown that P>0 is the necessary condition for black holes in general relativity to be thermodynamically stable, however this condition cannot be satisfied by many black holes in general relativity. For black hole in Gauss–Bonnet gravity negative pressure can be feasible, but only local stable black hole exists in this case.

  4. Stability criterion for superfluidity based on the density spectral function

    Science.gov (United States)

    Watabe, Shohei; Kato, Yusuke

    2013-12-01

    We study a stability criterion hypothesis for superfluids expressed in terms of the local density spectral function In(r,ω) that is applicable to both homogeneous and inhomogeneous systems. We evaluate the local density spectral function in the presence of a one-dimensional repulsive or attractive external potential within Bogoliubov theory, using solutions for the tunneling problem. We also evaluate the local density spectral function using an orthogonal basis, and calculate the autocorrelation function Cn(r,t). When superfluids in a d-dimensional system flow below a threshold, In(r,ω)∝ωd holds in the low-energy regime and Cn(r,t)∝1/td+1 holds in the long-time regime. However, when superfluids flow with the critical current, In(r,ω)∝ωβ holds in the low-energy regime and Cn(r,t)∝1/tβ+1 holds in the long-time regime with βstability criterion hypothesis recently proposed.

  5. Combined heterogeneous Electro-Fenton and biological process for the treatment of stabilized landfill leachate.

    Science.gov (United States)

    Baiju, Archa; Gandhimathi, R; Ramesh, S T; Nidheesh, P V

    2018-03-15

    Treatment of stabilized landfill leachate is a great challenge due to its poor biodegradability. Present study made an attempt to treat this wastewater by combining electro-Fenton (E-Fenton) and biological process. E-Fenton treatment was applied prior to biological process to enhance the biodegradability of leachate, which will be beneficial for the subsequent biological process. This study also investigates the efficiency of iron molybdophosphate (FeMoPO) nanoparticles as a heterogeneous catalyst in E-Fenton process. The effects of initial pH, catalyst dosage, applied voltage and electrode spacing on Chemical Oxygen Demand (COD) removal efficiency were analyzed to determine the optimum conditions. Heterogeneous E-Fenton process gave 82% COD removal at pH 2, catalyst dosage of 50 mg/L, voltage 5 V, electrode spacing 3 cm and electrode area 25 cm 2 . Combined E-Fenton and biological treatment resulted an overall COD removal of 97%, bringing down the final COD to 192 mg/L. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Familiarity facilitates feature-based face processing

    Science.gov (United States)

    Wheeler, Kelsey G.; Cipolli, Carlo; Gobbini, M. Ida

    2017-01-01

    Recognition of personally familiar faces is remarkably efficient, effortless and robust. We asked if feature-based face processing facilitates detection of familiar faces by testing the effect of face inversion on a visual search task for familiar and unfamiliar faces. Because face inversion disrupts configural and holistic face processing, we hypothesized that inversion would diminish the familiarity advantage to the extent that it is mediated by such processing. Subjects detected personally familiar and stranger target faces in arrays of two, four, or six face images. Subjects showed significant facilitation of personally familiar face detection for both upright and inverted faces. The effect of familiarity on target absent trials, which involved only rejection of unfamiliar face distractors, suggests that familiarity facilitates rejection of unfamiliar distractors as well as detection of familiar targets. The preserved familiarity effect for inverted faces suggests that facilitation of face detection afforded by familiarity reflects mostly feature-based processes. PMID:28582439

  7. [Effects of soil properties on the stabilization process of cadmium in Cd alone and Cd-Pb contaminated soils].

    Science.gov (United States)

    Wu, Man; Xu, Ming-Gang; Zhang, Wen-Ju; Wu, Hai-Wen

    2012-07-01

    In order to clarify the effects of soil properties on the stabilization process of the cadmium (Cd) added, 11 different soils were collected and incubated under a moisture content of 65%-70% at 25 degrees C. The changes of available Cd contents with incubation time (in 360 days) in Cd and Cd-Pb contaminated treatments were determined. The stabilization process was simulated using dynamic equations. The results showed that after 1.0 mg x kg(-1) Cd or 500 mg x kg(-1) Pb + 1.0 mg x kg(-1) Cd were added into the soil, the available Cd content decreased rapidly during the first 15 days, and then the decreasing rate slowed down, with an equilibrium content reached after 60 days' incubation. In Cd-Pb contaminated soils, the presence of Pb increased the content of available Cd. The stabilization process of Cd could be well described by the second-order equation and the first order exponential decay; meanwhile, dynamic parameters including equilibrium content and stabilization velocity were used to characterize the stabilization process of Cd. These two key dynamic parameters were significantly affected by soil properties. Correlation analysis and stepwise regression suggested that high pH and high cation exchange capacity (CEC) significantly retarded the availability of Cd. High pH had the paramount effect on the equilibrium content. The stabilization velocity of Cd was influenced by the soil texture. It took shorter time for Cd to get stabilized in sandy soil than in the clay.

  8. Novel delay-partitioning stabilization approach for networked control system via Wirtinger-based inequalities.

    Science.gov (United States)

    Li, Zhichen; Bai, Yan; Huang, Congzhi; Cai, Yunfei

    2016-03-01

    This paper studies the problems of stability analysis and state feedback stabilization for networked control system. By developing a novel delay-partitioning approach, the information on both the range of network-induced delay and the maximum number of consecutive data packet dropouts can be taken into full consideration. Various augmented Lyapunov-Krasovskii functionals (LKFs) with triple-integral terms are constructed for the two delay subintervals. Moreover, the Wirtinger-based inequalities in combination with an improved reciprocal convexity are utilized to estimate the derivatives of LKFs more accurately. The proposed approaches have improved the stability conditions without increasing much computational complexity. Based on the obtained stability criterion, a stabilization controller design approach is also given. Finally, four numerical examples are presented to illustrate the effectiveness and outperformance of the proposed approaches. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Sterically stabilized water based magnetic fluids: Synthesis, structure and properties

    Energy Technology Data Exchange (ETDEWEB)

    Bica, Doina [Laboratory of Magnetic Fluids, Center for Fundamental and Advanced Technical Research, Romanian Academy, Timisoara Division, Bd. Mihai Viteazul 24, 300223 Timisoara (Romania); Vekas, Ladislau [Laboratory of Magnetic Fluids, Center for Fundamental and Advanced Technical Research, Romanian Academy, Timisoara Division, Bd. Mihai Viteazul 24, 300223 Timisoara (Romania) and National Centre for Engineering of Systems with Complex Fluids, University Politehnica Timisoara, Bd. Mihai Viteazul 1, 300222 Timisoara (Romania)]. E-mail: vekas@acad-tim.tm.edu.ro; Avdeev, Mikhail V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Marinica, Oana [National Centre for Engineering of Systems with Complex Fluids, University Politehnica Timisoara, Bd. Mihai Viteazul 1, 300222 Timisoara (Romania); Socoliuc, Vlad [National Institute R and D for Electrochemistry and Condensed Matter, Str. Diaconu Coressi 144, 300588 Timisoara (Romania); Balasoiu, Maria [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation); Garamus, Vasil M. [GKSS Research Centre, Geesthacht (Germany)

    2007-04-15

    Magnetic fluids (MFs), prepared by chemical co-precipitation followed by double layer steric and electrostatic (combined) stabilization of magnetite nanoparticles dispersed in water, are presented. Several combinations of surfactants with different chain lengths (lauric acid (LA), myristic acid (MA), oleic acid (OA) and dodecyl-benzene-sulphonic acid (DBS)) were used, such as LA+LA, MA+MA, LA+DBS, MA+DBS, OA+DBS, OA+OA and DBS+DBS. Static light scattering, transmission electron microscopy, small angle neutron scattering, magnetic and magneto-rheological measurements revealed that MFs with MA+MA or LA+LA biocompatible double layer covered magnetite nanoparticles are the most stable colloidal systems among the investigated samples, and thus suitable for biomedical applications.

  10. THE BASING OF STABILIZATION PARAMETERS OF A FORTIFIED RAILWAY BED

    Directory of Open Access Journals (Sweden)

    V. D. Petrenko

    2014-12-01

    Full Text Available Purpose. The article is devoted to stabilization parameters determination of reinforced railway bed. At the present time, the railway plays the leading role in transport system to ensure the needs of freight and passenger traffic. In modern conditions railway operation concentrates on ensuring the necessary level of track reliability, including the roadbed, this is one of the main elements of road structures. The purpose of this article is the determination of basic parameters of stress-strain state to stabilize the soil subgrade embankment by reinforced materials. Methodology. To achieve this goal the following tasks of researches were solved: the effect of reinforcing layer of geomaterial on deformation properties of soil subgrade in various design of strengthening was investigated, the distributions of stresses in the subgrade were determined, reinforced of geomaterials under state load. Experimental studies to explore the nature of the deformation model subgrade at various degrees of stress were carried out. Findings. The analysis of the results of performed experimental and theoretical studies permitted to do the following conclusions. In conducting researches determined the distribution of stresses in the subgrade reinforced geomaterials under static load. The complex of experimental studies allows exploring the nature of the deformation model subgrade at various degrees of stress. Originality. On the basis of the theoretical studies have been regarded the problem of determining the stress-strain state of subgrade reinforced geomaterials by measuring stresses in its application for step loads. Practical value. The practical value was presented by the results of evaluating the effect of reinforcing way for changing the stress-strain state of subgrade.

  11. Optimizing stabilization of waste-activated sludge using Fered-Fenton process and artificial neural network modeling (KSOFM, MLP).

    Science.gov (United States)

    Badalians Gholikandi, Gagik; Masihi, Hamidreza; Azimipour, Mohammad; Abrishami, Ali; Mirabi, Maryam

    2014-01-01

    Sludge management is a fundamental activity in accordance with wastewater treatment aims. Sludge stabilization is always considered as a significant step of wastewater sludge handling. There has been a progressive development observed in the approach to the novel solutions in this regard. In this research, based on own initially experimental results in lab-scale regarding Fered-Fenton processes in view of organic loading (volatile-suspended solids, VSS) removal efficiency, a combination of both methods towards proper improving of excess biological sludge stabilization was investigated. Firstly, VSS removal efficiency has been experimentally studied in lab-scale under different operational conditions taking into consideration pH [Fe(2+)]/[H2O2], detention time [H2O2], and current density parameters. Therefore, the correlations of the same parameters have been determined by utilizing Kohonen self-organizing feature maps (KSOFM). In addition, multi-layer perceptron (MLP) has been employed afterwards for a comprehensive evaluation of investigating parameters correlation and prediction aims. The findings indicated that the best proportion of iron to hydrogen peroxide and the optimum pH were 0.58 and 3.1, respectively. Furthermore, maximum retention time about 6 h with a hydrogen peroxide concentration of 1,568 mg/l and a current density of 650-750 mA results to the optimum VSS removal (efficiency equals to 81 %). The performance of KSOFM and MLP models is found to be magnificent, with correlation ranging (R) from 0.873 to 0.998 for the process simulation and prediction. Finally, it can be concluded that the Fered-Fenton reactor is a suitable efficient process to reduce considerably sludge organic load and mathematical modeling tools as artificial neural networks are impressive methods of process simulation and prediction accordingly.

  12. Environmental Assessment for Shoreline Stabilization at Langley Air Force Base, Virginia

    National Research Council Canada - National Science Library

    Dischner, David M; Lingner, David; Rock, Howard B; Combs, Jennifer; Brandenburg, Catherine

    2006-01-01

    The United States Air Force (Air Force), 1st Fighter Wing (1 FW) proposes to implement various methods to stabilize the shoreline at several locations along the Back River waterfront at Langley Air Force Base (AFB...

  13. Flexibility and Stability in Sensory Processing Revealed Using Visual-to-Auditory Sensory Substitution

    Science.gov (United States)

    Hertz, Uri; Amedi, Amir

    2015-01-01

    The classical view of sensory processing involves independent processing in sensory cortices and multisensory integration in associative areas. This hierarchical structure has been challenged by evidence of multisensory responses in sensory areas, and dynamic weighting of sensory inputs in associative areas, thus far reported independently. Here, we used a visual-to-auditory sensory substitution algorithm (SSA) to manipulate the information conveyed by sensory inputs while keeping the stimuli intact. During scan sessions before and after SSA learning, subjects were presented with visual images and auditory soundscapes. The findings reveal 2 dynamic processes. First, crossmodal attenuation of sensory cortices changed direction after SSA learning from visual attenuations of the auditory cortex to auditory attenuations of the visual cortex. Secondly, associative areas changed their sensory response profile from strongest response for visual to that for auditory. The interaction between these phenomena may play an important role in multisensory processing. Consistent features were also found in the sensory dominance in sensory areas and audiovisual convergence in associative area Middle Temporal Gyrus. These 2 factors allow for both stability and a fast, dynamic tuning of the system when required. PMID:24518756

  14. Thermal stability of bimodal microstructure in magnesium alloy AZ91 processed by ECAP

    Energy Technology Data Exchange (ETDEWEB)

    Pantělejev, Libor, E-mail: pantelejev@fme.vutbr.cz [Institute of Materials Science and Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69 Brno (Czech Republic); NETME Centre, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69 Brno (Czech Republic); Štěpánek, Roman [Institute of Materials Science and Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69 Brno (Czech Republic); NETME Centre, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69 Brno (Czech Republic); Man, Ondřej [Institute of Materials Science and Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69 Brno (Czech Republic)

    2015-09-15

    The changes in microstructure of equal channel angular pressing (ECAP) processed magnesium alloy AZ91 during thermal exposure were studied in this paper. The microstructure stability was investigated by means of electron backscatter diffraction (EBSD), which allowed to measure the changes in grain size, mutual ratio of low-angle boundaries (LABs) to high-angle ones (HABs) and local lattice distortion evaluated by the kernel average misorientation (KAM) parameter. It was found experimentally that the threshold temperature at which significant grain coarsening takes place is 350 °C. No modification to mean grain diameter occurs below this temperature, nonetheless, some changes in LAB and HAB fraction, as well as in local lattice distortion, can be observed. - Highlights: • Thermal stability of bimodal UFG AZ91 alloy was assessed by means of EBSD. • Threshold temperature for pronounced grain coarsening was found at 350 °C. • Below 350 °C increase in LAB fraction and local lattice distortion takes place. • Local lattice distortion (LLD) can be well described using KAM approach. • LLD is influenced by coarsening and precipitation of Mg{sub 17}Al{sub 12} particles.

  15. Improved air stability of perovskite solar cells via solution-processed metal oxide transport layers

    Science.gov (United States)

    You, Jingbi; Meng, Lei; Song, Tze-Bin; Guo, Tzung-Fang; Yang, Yang (Michael); Chang, Wei-Hsuan; Hong, Ziruo; Chen, Huajun; Zhou, Huanping; Chen, Qi; Liu, Yongsheng; De Marco, Nicholas; Yang, Yang

    2016-01-01

    Lead halide perovskite solar cells have recently attracted tremendous attention because of their excellent photovoltaic efficiencies. However, the poor stability of both the perovskite material and the charge transport layers has so far prevented the fabrication of devices that can withstand sustained operation under normal conditions. Here, we report a solution-processed lead halide perovskite solar cell that has p-type NiOx and n-type ZnO nanoparticles as hole and electron transport layers, respectively, and shows improved stability against water and oxygen degradation when compared with devices with organic charge transport layers. Our cells have a p-i-n structure (glass/indium tin oxide/NiOx/perovskite/ZnO/Al), in which the ZnO layer isolates the perovskite and Al layers, thus preventing degradation. After 60 days storage in air at room temperature, our all-metal-oxide devices retain about 90% of their original efficiency, unlike control devices made with organic transport layers, which undergo a complete degradation after just 5 days. The initial power conversion efficiency of our devices is 14.6 ± 1.5%, with an uncertified maximum value of 16.1%.

  16. Storage stability of traditional Tunisian butter enriched with antioxidant extract from tomato processing by-products.

    Science.gov (United States)

    Abid, Yousra; Azabou, Samia; Jridi, Mourad; Khemakhem, Ibtihel; Bouaziz, Mohamed; Attia, Hamadi

    2017-10-15

    Traditional Tunisian butter (TTB) is one of the most appreciated dairy products in Tunisia. Herein, the storage stability of TTB enriched with antioxidants from tomato processing by-products (TPB) was evaluated during 60days of storage at 4°C. TPB extract contains significant amounts of lycopene and phenolics. TTB enriched with 400mg of TPB extract/kg of TTB revealed the lowest peroxide values at all the determination intervals. Adding 400mg of TPB extract/kg of TTB did not exhibit any undesired effect on lactic bacteria which are necessary for development of aroma and chemical properties of TTB. However, raw TTB and highly enriched TTB (800mg of TPB extract/kg of TTB) displayed higher lipid peroxidation. The detrimental effect of high antioxidant amounts on TTB stability could be due to a possible pro-oxidant character. Thus, appropriate supplementation of TPB extract could be used in TTB as a protective agent against lipid peroxidation to extend its shelf-life up to two months. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Residue-based Coordinated Selection and Parameter Design of Multiple Power System Stabilizers (PSSs)

    DEFF Research Database (Denmark)

    Su, Chi; Hu, Weihao; Fang, Jiakun

    2013-01-01

    Residue method is a commonly used approach to design the parameters of a power system stabilizer (PSS). In this paper, a residue identification method is adopted to obtain the system residues for different input-output pairs, using the system identification toolbox in MATLAB with the measurement...... as the test system is built in DIgSIELNT PowerFactory 14.0, in which the proposed coordination method is validated by time domain simulations and modal analysis....... data from time domain simulations. Then a coordinated approach for multiple PSS selection and parameter design based on residue method is proposed and realized in MATLAB m-files. Particle swarm optimization (PSO) is adopted in the coordination process. The IEEE 39-bus New England system model...

  18. Stabilizing operation point technique based on the tunable distributed feedback laser for interferometric sensors

    Science.gov (United States)

    Mao, Xuefeng; Zhou, Xinlei; Yu, Qingxu

    2016-02-01

    We describe a stabilizing operation point technique based on the tunable Distributed Feedback (DFB) laser for quadrature demodulation of interferometric sensors. By introducing automatic lock quadrature point and wavelength periodically tuning compensation into an interferometric system, the operation point of interferometric system is stabilized when the system suffers various environmental perturbations. To demonstrate the feasibility of this stabilizing operation point technique, experiments have been performed using a tunable-DFB-laser as light source to interrogate an extrinsic Fabry-Perot interferometric vibration sensor and a diaphragm-based acoustic sensor. Experimental results show that good tracing of Q-point was effectively realized.

  19. An Impedance-Based Stability Analysis Method for Paralleled Voltage Source Converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    This paper analyses the stability of paralleled voltage source converters in AC distributed power systems. An impedance-based stability analysis method is presented based on the Nyquist criterion for multiloop system. Instead of deriving the impedance ratio as usual, the system stability...... of converter and the passive network can also be predicted by the Nyquist diagrams. This method is applied to evaluate the current and voltage controller interactions of converters in both grid-connected and islanded operations. Simulations and experimental results verify the effectiveness of theoretical...... analysis....

  20. Problem Based Learning and the scientific process

    Science.gov (United States)

    Schuchardt, Daniel Shaner

    This research project was developed to inspire students to constructively use problem based learning and the scientific process to learn middle school science content. The student population in this study consisted of male and female seventh grade students. Students were presented with authentic problems that are connected to physical and chemical properties of matter. The intent of the study was to have students use the scientific process of looking at existing knowledge, generating learning issues or questions about the problems, and then developing a course of action to research and design experiments to model resolutions to the authentic problems. It was expected that students would improve their ability to actively engage with others in a problem solving process to achieve a deeper understanding of Michigan's 7th Grade Level Content Expectations, the Next Generation Science Standards, and a scientific process. Problem based learning was statistically effective in students' learning of the scientific process. Students statistically showed improvement on pre to posttest scores. The teaching method of Problem Based Learning was effective for seventh grade science students at Dowagiac Middle School.

  1. Posturography stability score generation for stroke patient using Kinect: Fuzzy based approach.

    Science.gov (United States)

    Mazumder, Oishee; Chakravarty, Kingshuk; Chatterjee, Debatri; Sinha, Aniruddha; Das, Abhijit

    2017-07-01

    Aim of this paper is to formulate a posturography stability score for stroke patients using fuzzy logic. Postural instability is one of the prominent symptoms of stroke, dementia, parkinsons disease, myopathy, etc. and is the major precursor of fall. Conventional scoring techniques used to assess postural stability require manual intervention and are dependent on live interaction with physiotherapist. We propose a novel scoring technique to calculate static stability of a person using posturography features acquired by Kinect sensor, which do not require any manual intervention or expert guidance, is cost effective and hence are ideal for tele rehabilitation purpose. Stability analysis is done during Single Limb Stance (SLS) exercise. Kinect sensor is used to calculate three features, naming SLS duration, vibration index, calculated from mean vibration of twenty joints and sway area of Centre of Mass (CoM). Based on the variation of these features, a fuzzy rule base is generated which calculates a static stability score. One way analysis of variance (Anova) between a group of stroke population and healthy individuals under study validates the reliability of the proposed scorer. Generated fuzzy score are comparable with standard stability scorer like Berg Balance scale and fall risk assessment tool like Johns Hopkins scale. Stability score, besides providing an index of overall stability can also be used as a fall predictability index.

  2. Matchmaking for business processes based on choreographies

    NARCIS (Netherlands)

    Wombacher, Andreas; Fankhauser, Peter; Mahleko, Bendick; Neuhold, Erich

    Web services have a potential to enhance B2B ecommerce over the Internet by allowing companies and organizations to publish their business processes on service directories where potential trading partners can find them. This can give rise to new business paradigms based on ad-hoc trading relations

  3. Research progress on trifluoromethyl-based radical reaction process

    Science.gov (United States)

    Song, Hao

    2017-12-01

    Due to the unique properties imparted by the trifluoromethyl group, such as high electron density and strong lipotropy, which effectively improve acidity, lipophilicity and metabolic stability of the molecule itself, trifluoromethyl-substituted organic compounds are becoming increasingly important as structural motifs in pharmaceuticals, agrochemicals and organic materials. In this review, we present several methods developed for the direct introduction of a trifluoromethyl group, beginning with its rich and storied history. Then the present article addresses mechanism and process in carbon-carbon bond forming reaction based on radical process which is divided into three parts according to the way of CF3 radical generation. Finally, challenges and opportunities of researches on trifluoromethylation reactions facing are prospected.

  4. Catalyst based processes at back end of nuclear fuel cycle

    International Nuclear Information System (INIS)

    Vincent, T.

    2013-01-01

    Heterogeneous catalysts occupy a pivotal position in chemical industry. Their advanced preparation technology allows us to employ these catalysts for wide range of application. But the deployment of catalyst based radiochemical technology has to address the particular features like aggressive nitric acid media and intensive radiation fields. This put forward the rigid requirements to a choice of catalysts: high chemical and radiation stability of the catalyst and support, mechanical durability, catalytic activity and simplicity of preparation. Hydrogenation process with Pt/SiO 2 has been adopted industrially for making uranous nitrate (U 4+ ) from uranyl nitrate (U 6+ ) in PUREX process at commercial reprocessing plants. Bimetallic catalysts are being explored for the destruction of nitrates generated during nuclear fuel cycle operations

  5. Stabilization/solidification of a municipal solid waste incineration residue using fly ash-based geopolymers.

    Science.gov (United States)

    Luna Galiano, Y; Fernández Pereira, C; Vale, J

    2011-01-15

    The stabilization/solidification (S/S) of a municipal solid waste incineration (MSWI) fly ash containing hazardous metals such as Pb, Cd, Cr, Zn or Ba by means of geopolymerization technology is described in this paper. Different reagents such as sodium hydroxide, potassium hydroxide, sodium silicate, potassium silicate, kaolin, metakaolin and ground blast furnace slag have been used. Mixtures of MSWI waste with these kinds of geopolymeric materials and class F coal fly ash used as silica and alumina source have been processed to study the potential of geopolymers as waste immobilizing agents. To this end, the effects of curing conditions and composition have been tested. S/S solids are submitted to compressive strength and leaching tests to assess the results obtained and to evaluate the efficiency of the treatment. Compressive strength values in the range 1-9 MPa were easily obtained at 7 and 28 days. Concentrations of the metals leached from S/S products were strongly pH dependent, showing that the leachate pH was the most important variable for the immobilization of metals. Comparison of fly ash-based geopolymer systems with classical Portland cement stabilization methods has also been accomplished. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Waste stabilization/solidification of an electric arc furnace dust using fly ash-based geopolymers

    Energy Technology Data Exchange (ETDEWEB)

    C. Fernandez Pereira; Y. Luna; X. Querol; D. Antenucci; J. Vale [University of Seville, Seville (Spain). School of Industrial Engineering

    2009-07-15

    The stabilization/solidification (S/S) of a carbon steel electric arc furnace (EAF) dust containing hazardous metals such as Pb, Cd, Cr or Zn using geopolymerization technology is described in this paper. Different reagents such as sodium hydroxide, potassium hydroxide, sodium silicate, potassium silicate, kaolinite, metakaolinite and blast furnace slag have been used. Mixtures of EAF waste with these geopolymeric materials and class F fly ash have been processed for studying the potential of geopolymers as waste immobilizing agents. Compressive strength tests and leaching tests for determining the efficiency of heavy metal immobilisation have been carried out. Comparison of fly ash-based geopolymer systems with classic Portland cement stabilization methods has also been accomplished. Compressive strength values far better than those achieved by hydraulic S/S methods were easily obtained by geopolymer solids at 28 days. Regarding leachability, the geopolymer S/S solids also manifested in general a better behaviour, showing very promising results. 40 refs., 1 fig., 9 tabs.

  7. Power System Stabilization Control Based on the Wide Area Phasor Measurement

    Science.gov (United States)

    Watanabe, Masayuki; Hashiguchi, Takuhei; Izumi, Takanori; Mitani, Yasunori

    This paper presents a method for tuning of power system stabilizers (PSS) for damping low-frequency oscillations in a multi-machine power system based on the wide area phasor measurement. The authors have developed a method for detecting inter-area low-frequency modes from the measured small oscillation associated with the load fluctuation by approximating oscillations as a coupled vibration model. In this paper, the coupled vibration model is extended for including the effect of PSSs. PSSs are tuned directly by using the extended model since the model includes parameters of PSSs. The advantage of this method is that steady state phasor fluctuations are available to tuning PSSs and assess the effect of the tuning control. In other words, a large disturbance like a line fault is not necessary since the stability of the major modes can be investigated directly by using eigenvalues of the extended model. The identification process does not require the information on the input to the system for perturbation. Some numerical analyses demonstrate the effectiveness of the method by using phasor dynamical data obtained by a power system simulation package.

  8. PLASMA THERMAL BARRIER COATINGS BASED ON ZIRCONIUM DIOXIDE WITH HIGH THERMAL STABILITY

    Directory of Open Access Journals (Sweden)

    O. G. Devoino

    2015-01-01

    Full Text Available The paper presents optimization of  processes for obtaining maximum content of tetragonal phase in the initial material and thermal barrier coatings (TBC based on zirconium dioxide and hafnium oxide.  Results of the investigations on phase composition of oxide HfO2 – ZrO2 – Y2O3  system have been given in the paper. The system represents  a microstructure which is similar to  zirconia dioxide and  transformed for its application at 1300 °C. The paper explains a mechanism of hafnium oxide influence on formation of the given microstructure. The research methodology has been based on complex metallography, X – ray diffraction and electron microscopic investigations of  structural elements of the composite plasma coating HfO2 – ZrO2 – Y2O system.In order to stabilize zirconium dioxide  dopant oxide should not only have an appropriate size of  metal ion, but also form a solid solution with the zirconia. This condition severely limits the number of possible stabilizers. In fact, such stabilization is possible only with the help of rare earth oxides (Y2O3, Yb2O3, CeO2, HfO2. Chemical purity of the applied materials plays a significant role for obtaining high-quality thermal barrier coatings. Hafnium oxide has been selected as powder for thermal barrier coatings instead of zirconium dioxide due to their similarities in structural modification, grating, chemical and physical properties and its high temperature structural transformations. It has been established that plasma thermal barrier HfO2 – ZrO2 – Y2O3 coatings consist of  one tetragonal phase. This phase is equivalent to a non-equilibrium tetragonal t' phase in the “zirconium dioxide stabilized with yttrium oxide” system. Affinity of  Hf+4 and Zr+4 cations leads to the formation of identical metastable phases during rapid quenching.

  9. Development of a manufacturing process for Zr-based spacer grid materials

    International Nuclear Information System (INIS)

    Jung, Yang-Il; Lee, Myung-Ho; Choi, Byoung-Kwon; Park, Jeong-Yong; Jeong, Yong-Hwan

    2009-01-01

    A novel manufacturing process for zirconium-based alloy strips has been developed. This process consists of a prior heat-treatment under a monotectoid temperature before subsequent deformation processes. During the prior heat-treatment process at 580 deg. C for 10 h, β-Nb phase particles were precipitated. The second phase particles stabilized the alloy from corrosion even the subsequent annealings at high temperatures. This result enhances the manufacturability of zirconium-based alloys, especially for high strength alloys with high Nb contents. The process developed can also be applied to commercial zirconium-based spacer grid materials, which would give rise to a higher producibility of such materials.

  10. Processing data base information having nonwhite noise

    Science.gov (United States)

    Gross, Kenneth C.; Morreale, Patricia

    1995-01-01

    A method and system for processing a set of data from an industrial process and/or a sensor. The method and system can include processing data from either real or calculated data related to an industrial process variable. One of the data sets can be an artificial signal data set generated by an autoregressive moving average technique. After obtaining two data sets associated with one physical variable, a difference function data set is obtained by determining the arithmetic difference between the two pairs of data sets over time. A frequency domain transformation is made of the difference function data set to obtain Fourier modes describing a composite function data set. A residual function data set is obtained by subtracting the composite function data set from the difference function data set and the residual function data set (free of nonwhite noise) is analyzed by a statistical probability ratio test to provide a validated data base.

  11. The stability of temporary prosthetic base materials. I: Introduction, angular changes and dimensional stability.

    Science.gov (United States)

    Heath, J R; Boru, T K; Grant, A A

    1993-07-01

    The bases of occlusal rims and trial dentures should fit both the cast and the mouth accurately. The retention of shape and dimension of strips and sheets of grey and pink shellac, filled cold cure acrylic resin and wax were tested following moulding over stylised upper edentulous casts. The thermoplastic materials were softened over a flame or in a water bath. Specimens were prepared with and without folding along the long axes of the strips. The angles formed by the strips, the gap between the palate of the baseplates and casts and the linear dimension of the sheets were measured after moulding, after immersion in water at 37 and 45 degrees C and after 24 h at room temperature. The least angular change was shown by unfolded grey shellac, softened over a flame and moulded by finger pressure over an unwarmed cast, followed by folded specimens softened in water and moulded with the fingers over a prewarmed cast. The least gap developed beneath pink shellac softened in water and moulded by finger pressure over a warmed cast. The smallest dimensional change was shown by grey shellac softened in water and moulded by finger pressure over a warmed cast. Thus, optimally manipulated shellac materials exhibit less change after moulding than cold cure acrylic resin or modelling wax.

  12. Acid-base equilibrium. A thermodynamic study of formation and stability of the Bi-2223 phase

    International Nuclear Information System (INIS)

    Xi, Z.; Zhou, L.

    1993-01-01

    A general acid-base equilibrium theory was proposed to explain the formation and stability of the Bi-2223 phase based on the Lewis acid base theory and principle of metallurgical physical chemistry. The acid-base nature of oxide was defined according to the electrostatic force between cation and oxygen anion. A series of experimental facts were systematically explained based on the theory: substitution of Bi for Ca in the Pb-free 2223 phase, and the effect of substitution of the high-valent cation for Bi 3+ ; oxygen-pressure atmosphere, and the heat-schocking technique on the formation and stability of the 2223 phase. 14 refs., 2 tabs

  13. A novel and computationally efficient algorithm for stability analysis of multi input-multi output process control systems

    Energy Technology Data Exchange (ETDEWEB)

    Fatoorehchi, Hooman; Abolghasemi, Hossein; Zarghami, Reza [University of Tehran, Tehran (Iran, Islamic Republic of); Rach, Randolph [The George Adomian Center for Applied Mathematics, Hartford (United States); Freeden, Sebastian von [Institute for Control Engineering of Machine Tools and Manufacturing Units, University of Stuttgart (Germany)

    2015-09-15

    An efficient method based on the Faddeev-Leverrier algorithm combined with the Adomian decomposition method is devised to facilitate the stability analysis of multi-input multi-output control systems. In contrast to prior eigenvalue algorithms, our method affords all eigenvalues of the state matrix, either real or complex. Specifically, the calculation of the complex eigenvalues is made possible through special canonical forms, mainly involving square root operators, of the characteristic equation of the state matrix. Moreover, the proposed method does not require an initial guess, which is often a matter of concern since an inappropriate guess can cause failure in such available schemes. For the sake of illustration, a number of numerical examples, including chemical reaction processes, are also provided that demonstrate the efficiency of our new technique.

  14. Thermal Shock Resistance of Stabilized Zirconia/Metal Coat on Polymer Matrix Composites by Thermal Spraying Process

    Science.gov (United States)

    Zhu, Ling; Huang, Wenzhi; Cheng, Haifeng; Cao, Xueqiang

    2014-12-01

    Stabilized zirconia/metal coating systems were deposited on the polymer matrix composites by a combined thermal spray process. Effects of the thicknesses of metal layers and ceramic layer on thermal shock resistance of the coating systems were investigated. According to the results of thermal shock lifetime, the coating system consisting of 20 μm Zn and 125 μm 8YSZ exhibited the best thermal shock resistance. Based on microstructure evolution, failure modes and failure mechanism of the coating systems were proposed. The main failure modes were the formation of vertical cracks and delamination in the outlayer of substrate, and the appearance of coating spallation. The residual stress, thermal stress and oxidation of substrate near the substrate/metal layer interface were responsible for coating failure, while the oxidation of substrate near the substrate/coating interface was the dominant one.

  15. Dimensional stability and dehydration of a thermoplastic polycarbonate-based and two PMMA-based denture resins.

    Science.gov (United States)

    Pronych, G J; Sutow, E J; Sykora, O

    2003-12-01

    This study compared the dimensional stability and dehydration of a thermoplastic polycarbonate denture base resin with two conventional polymethyl methacrylate denture base resins. Maxillary complete dentures were fabricated from the three denture materials and the accuracy of fit along the posterior palatal border of the cast used in processing was measured. Measurements were conducted at five palatal locations immediately after processing and at 7 and 30 days during immersion in water (23 degrees C) and at 7 and 30 days during dehydration (23 degrees C, 65-75% relative humidity). Percentage mass loss during dehydration was determined with an electronic balance. The thermoplastic material was separately compared with each of the conventional resins using a modified Welch two-sample t-test, with a Bonferroni correction for P values. For mean palatal dimensional change, the thermoplastic resin was generally not statistically different from the conventional resins after processing and during immersion (P > or = 0.06), but was generally less than the conventional resins during dehydration (P thermoplastic resin consistently showed much smaller, statistically significant values compared with the conventional resins (P thermoplastic resin should show dimensional changes in service comparable with the conventional resins, but less dimensional change caused by dehydration.

  16. Investigation of Dispersion, Stability, and Tribological Performance of Oil-Based Aluminum Oxide Nanofluids

    Science.gov (United States)

    2012-01-01

    laboratories used strictly, quality controlled nanofluids in the NIST RM 8012 and IRMM- 304 . The NIST RM 8012 nanofluid is an aqueous solution that contains...30 nm citrate-stabilized gold nanoparticles. The IRMM- 304 is a 40 nm diameter silica nanofluid with sodium hydroxide as a stabilizer. There was...process. A ball-on-flat friction tester was used with a 2 mm steel ball and an AISI 1045 steel flat. The maximum contact pressure was 1 GPa, and

  17. Cement-Based solidification/stabilization of red mud: Leaching properties of heavy metals

    OpenAIRE

    Tınmaz Köse, Esra; Akyıldız, Aylin

    2018-01-01

    Inthis study, convenience of solidification / stabilization process for disposaland recycling of the red mud produced from Konya Seydişehir Aluminum Plant wereexamined. For this purpose physical and chemical properties of the red mud wasprimarily demonstrated. In order to solidification, mortar was produced withdiffirent ratios of red mud by blending with cement. The stabilization ofsolidified material was examined via leaching test. According to the results ofleaching test, landfilling of th...

  18. Comprehensive Stability Evaluation of Rock Slope Using the Cloud Model-Based Approach

    Science.gov (United States)

    Liu, Zaobao; Shao, Jianfu; Xu, Weiya; Xu, Fei

    2014-11-01

    This article presents the cloud model-based approach for comprehensive stability evaluation of complicated rock slopes of hydroelectric stations in mountainous area. This approach is based on membership cloud models which can account for randomness and fuzziness in slope stability evaluation. The slope stability is affected by various factors and each of which is ranked into five grades. The ranking factors are sorted into four categories. The ranking system of slope stability is introduced and then the membership cloud models are applied to analyze each ranking factor for generating cloud memberships. Afterwards, the obtained cloud memberships are synthesized with the factor weights given by experts for comprehensive stability evaluation of rock slopes. The proposed approach is used for the stability evaluation of the left abutment slope in Jinping 1 Hydropower Station. It is shown that the cloud model-based strategy can well consider the effects of each ranking factor and therefore is feasible and reliable for comprehensive stability evaluation of rock slopes.

  19. Thermal stability of antiparasitic macrocyclic lactones milk residues during industrial processing.

    Science.gov (United States)

    Imperiale, F A; Farias, C; Pis, A; Sallovitz, J M; Lifschitz, A; Lanusse, C

    2009-01-01

    The chemical stability of residues of different antiparasitic macrocyclic lactone compounds in milk subjected to thermal treatment was assessed. Concentrations of ivermectin (IVM), moxidectin (MXD) and eprinomectin (EPM) in sheep milk, equivalent to those measured in vivo in milk excretion studies, were subjected to 65 degrees C over 30 min or to 75 degrees C for 15 s. Residue concentrations of IVM, MXD and EPM in milk were measured by high-performance liquid chromatography (HPLC) (fluorescence detection) before and after heat treatment of the drug-fortified milk samples. No evidence of chemical loss was obtained in either of the thermal treatments under evaluation. The stability of the parent compounds in milk was evidenced by the lack of bioconversion products (metabolites) after both thermal treatments. Only very minor changes on drug concentrations were observed at the end of the treatments, which fell within the limits of the variation of the validated analytical method. In conclusion, residue concentrations of macrocyclic lactones are unaffected by industrial-simulated milk thermal procedures. Based on the reported findings, it can be postulated that residue concentrations of IVM, MXD and EPM measured in raw sheep milk may be used to estimate consumer exposure and dietary intake for these veterinary drugs.

  20. Power System Stability Improvement through the Coordination of TCPS-based Damping Controller and Power System Stabilizer

    Directory of Open Access Journals (Sweden)

    ALI, M. A. S.

    2017-11-01

    Full Text Available To guarantee the secure and reliable operations of power systems through the rapid damping of low-frequency electromechanical oscillations (LFEOs is the ultimate objective of this study. This paper presents a coordination of a flexible AC transmission system (FACTS device and power system stabilizer (PSS to meet this objective, and deals with the design of a damping controller based on a thyristor-controlled phase shifter (TCPS and a PSS. The proposed design is incorporated in the framework of a single-machine infinite-bus (SMIB power system. The effectiveness of the proposed design in damping power system oscillations is explored through eigenvalue analysis, time-domain simulations and damping torque contribution. A comparative study on different control schemes, such as with an SMIB including a PSS and an SMIB including a TCPS-based damping controller is also carried out. The obtained results prove the superior performance of the proposed design in improving the stability of the given power system. All the digital simulations are performed using MATLAB/ SIMULINK.

  1. Yield stability of processing sweet corn and relationship to genotype adoption

    Science.gov (United States)

    Yield stability is a crop genotype’s performance over a range of environmental conditions, such that a specific genotype may be less sensitive to environmental change (i.e. above-average stability) or more sensitive to environmental change (i.e. below-average stability) relative to other genotypes. ...

  2. Longitudinal stability of social cognition in schizophrenia: A 5-year follow-up of social perception and emotion processing.

    Science.gov (United States)

    McCleery, Amanda; Lee, Junghee; Fiske, Alan P; Ghermezi, Livon; Hayata, Jacqueline N; Hellemann, Gerhard S; Horan, William P; Kee, Kimmy S; Kern, Robert S; Knowlton, Barbara J; Subotnik, Kenneth L; Ventura, Joseph; Sugar, Catherine A; Nuechterlein, Keith H; Green, Michael F

    2016-10-01

    Individuals with schizophrenia exhibit marked and disproportional impairment in social cognition, which is associated with their level of community functioning. However, it is unclear whether social cognitive impairment is stable over time, or if impairment worsens as a function of illness chronicity. Moreover, little is known about the longitudinal associations between social cognition and community functioning. Forty-one outpatients with schizophrenia completed tests of emotion processing (Mayer-Salovey-Caruso Emotional Intelligence Test, MSCEIT) and social perception (Relationships Across Domains, RAD) at baseline and approximately five years later. Stability of performance was assessed using paired t-tests and correlations. Longitudinal associations between social cognition and community functioning (Role Functioning Scale, RFS) were assessed using cross-lagged panel correlation analysis. Performance on the two social cognition tasks were stable over follow-up. There were no significant mean differences between assessment points [p's≥0.20, Cohen'sd's≤|0.20|], and baseline performance was highly correlated with performance at follow-up [ρ's≥0.70, ICC≥0.83, p'ssocial cognition and community functioning was moderately large at follow-up [ρ=0.49, p=0.002]. However, baseline social cognition did not show a significant longitudinal influence on follow-up community functioning [z=0.31, p=0.76]. These data support trait-like stability of selected areas of social cognition in schizophrenia. Cross-lagged correlations did not reveal a significant unidirectional influence of baseline social cognition on community functioning five years later. However, consistent with the larger literature, a moderately large cross-sectional association between social cognition and community functioning was observed. Based on stability and cross-sectional associations, these results suggest that social cognition might have short-term implications for functional outcome rather than

  3. Functional relationship-based alarm processing system

    Science.gov (United States)

    Corsberg, D.R.

    1988-04-22

    A functional relationship-based alarm processing system and method analyzes each alarm as it is activated and determines its relative importance with other currently activated alarms and signals in accordance with the functional relationships that the newly activated alarm has with other currently activated alarms. Once the initial level of importance of the alarm has been determined, that alarm is again evaluated if another related alarm is activated or deactivated. Thus, each alarm's importance is continuously updated as the state of the process changes during a scenario. Four hierarchical relationships are defined by this alarm filtering methodology: (1) level precursor (usually occurs when there are two alarm settings on the same parameter); (2) direct precursor (based on causal factors between two alarms); (3) required action (system response or action expected within a specified time following activation of an alarm or combination of alarms and process signals); and (4) blocking condition (alarms that are normally expected and are not considered important). The alarm processing system and method is sensitive to the dynamic nature of the process being monitored and is capable of changing the relative importance of each alarm as necessary. 12 figs.

  4. Self-stabilizing optical clock pulse-train generator using SOA and saturable absorber for asynchronous optical packet processing.

    Science.gov (United States)

    Nakahara, Tatsushi; Takahashi, Ryo

    2013-05-06

    We propose a novel, self-stabilizing optical clock pulse-train generator for processing preamble-free, asynchronous optical packets with variable lengths. The generator is based on an optical loop that includes a semiconductor optical amplifier (SOA) and a high-extinction spin-polarized saturable absorber (SA), with the loop being self-stabilized by balancing out the gain and absorption provided by the SOA and SA, respectively. The optical pulse train is generated by tapping out a small portion of a circulating seed pulse. The convergence of the generated pulse energy is enabled by the loop round-trip gain function that has a negative slope due to gain saturation in the SOA. The amplified spontaneous emission (ASE) of the SOA is effectively suppressed by the SA, and a backward optical pulse launched into the SOA enables overcoming the carrier-recovery speed mismatch between the SOA and SA. Without external control for the loop gain, a stable optical pulse train consisting of more than 50 pulses with low jitter is generated from a single 10-ps seed optical pulse even with a variation of 10 dB in the seed pulse intensity.

  5. Controlling the chemical stability of a moisture-sensitive drug product through monitoring and identification of coating process microenvironment.

    Science.gov (United States)

    Kestur, Umesh; Pandey, Preetanshu; Badawy, Sherif; Lin, Judy; Desai, Divyakant

    2014-12-10

    The objective of this work was to monitor and identify the impact of coating microenvironment, as measured by PyroButtons(®) data loggers, on the chemical stability of a moisture-sensitive drug molecule brivanib alaninate (BA). BA tablets were coated at two different scales (15 and 24 in pan). PyroButtons(®) data loggers were allowed to move freely within the tablet bed to record the temperature and relative humidity conditions of the tablet bed. The tablet moisture content at the end of the coating runs, and the rate of hydrolysis of the BA tablets based on HPLC analysis was found to be a function of the coating thermodynamic microenvironment. Wetter coating conditions resulted in tablets with higher water content and showed greater degradation upon storage. The coating process which yielded acceptable stability in a 15 in coater was transferred to a 24 in coater by maintaining similar tablet-bed relative humidity and temperature conditions. This was compared to a traditional scale-up approach where the environmental equivalency factor (EEF) was matched between scales during coating. The moisture content observed across the two scales indicated that maintaining a similar tablet-bed microenvironment ensured consistent results between scales. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Crystallization behaviour and thermal stability of two aluminium-based metallic glass powder materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.P.; Yan, M. [University of Queensland, School of Mechanical and Mining Engineering, ARC Centre of Excellence for Design in Light Metals, Brisbane, QLD 4072 (Australia); Yang, B.J. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, J.Q., E-mail: jqwang@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Schaffer, G.B. [University of Queensland, School of Mechanical and Mining Engineering, ARC Centre of Excellence for Design in Light Metals, Brisbane, QLD 4072 (Australia); Qian, M., E-mail: ma.qian@uq.edu.au [University of Queensland, School of Mechanical and Mining Engineering, ARC Centre of Excellence for Design in Light Metals, Brisbane, QLD 4072 (Australia)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer The crystallization paths and products of Al{sub 86}Ni{sub 7}Y{sub 4.5}Co{sub 1}La{sub 1.5} powder have been identified. Black-Right-Pointing-Pointer The thermal stability of Al{sub 86}Ni{sub 7}Y{sub 4.5}Co{sub 1}La{sub 1.5} powder has been assessed. Black-Right-Pointing-Pointer The Al{sub 86}Ni{sub 7}Y{sub 4.5}Co{sub 1}La{sub 1.5} powder shows a wide processing window of 75 K. Black-Right-Pointing-Pointer The powder has the potential to be consolidated into thick BMG components based on the findings. Black-Right-Pointing-Pointer The Al{sub 85}Ni{sub 5}Y{sub 6}Co{sub 2}Fe{sub 2} powder shows similar characteristics but inferior thermal stability. - Abstract: The crystallization behaviour and thermal stability of two Al-based metallic glass powder materials, Al{sub 85}Ni{sub 5}Y{sub 6}Co{sub 2}Fe{sub 2} and Al{sub 86}Ni{sub 6}Y{sub 4.5}Co{sub 2}La{sub 1.5}, have been investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD) and electron microscopy. Both alloy powders show a distinct three-stage crystallization process with a similar gap of {approx}75 K between the onset crystallization temperature (T{sub x}) and the second crystallization temperature. Crystallization occurs by the precipitation and growth of fcc-Al, without intermetallic formation. The apparent activation energy for each stage of crystallization was determined from DSC analyses and the phases resulting from each crystallization stage were identified by XRD and electron microscopy. The critical cooling rate for each alloy powder was calculated from the DSC data. These results are necessary to inform the consolidation of amorphous powder particles of Al{sub 85}Ni{sub 5}Y{sub 6}Co{sub 2}Fe{sub 2} or Al{sub 86}Ni{sub 6}Y{sub 4.5}Co{sub 2}La{sub 1.5} into thick (>1 mm) metallic glass components.

  7. Global stability-based design optimization of truss structures using ...

    Indian Academy of Sciences (India)

    objective optimization; island models; genetic algorithm; arc-length method. ... Furthermore, a pure pareto-ranking based multi-objective optimization model is employed for the design optimization of the truss structure with multiple objectives.

  8. Tartaric stabilization of a Reserve Ruby Port Wine by cold and electrodialysis processes: Effect on chemical and sensory characteristics

    OpenAIRE

    Jorge, Nuno; Vilela, Alice; Braga, António; M. Nunes, Fernando; Cosme, Fernanda

    2014-01-01

    Cold stabilization is the most common wine operation for wine tartaric stabilization. This operation consists in cooling the wine at temperatures near the wine freezing point [1, 2], to induce potassium bitartrate crystals precipitation. However, this is a slow and costly operation. Electrodialysis is a process that allows the separation of anions and cations according to their electrical charge through a selective permeability membrane, by the passage of an electric field [3-6]. Electrodialy...

  9. Eigenvalue-based harmonic stability analysis method in inverter-fed power systems

    OpenAIRE

    Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

    2015-01-01

    This paper presents an eigenvalue-based harmonic stability analysis method for inverter-fed power systems. A full-order small-signal model for a droop-controlled Distributed Generation (DG) inverter is built first, including the time delay of digital control system, inner current and voltage control loops, and outer droop-based power control loop. Based on the inverter model, an overall small-signal model of a two-inverter-fed system is then established, and the eigenvalue-based stability ana...

  10. Beam shaping diffuser based fiber injection for increasing stability of industrial robotic laser applications

    Science.gov (United States)

    Lizotte, Todd E.; Dickey, Fred M.

    2013-09-01

    This paper documents the investigation of a diffuser based fiber injection system and its successful implementation and experimental testing in a robotic industrial process. This is a new concept based on the idea that a diffuser that has the angular radiation pattern matching the NA of the fiber can be used to approximate the field pattern at the face of a mode filled fiber. The research considered two approaches to this problem. The two related approaches to the problem were developed conceptually and analytically for two predominant wavelengths of interest, 1030 nm and 532 nm. The first is an implementation that would consist of illuminating the diffuser with a uniform spot having the same shape as the fiber core and imaging the illuminated spot onto the fiber face. The other approach is the use of a far-field (Fourier transform) diffractive element with a transform lens. This paper will provide an overview of the analytics and testing of the later concept (Fourier transform) and the experimental implementation of the design to a laser fiber coupling system to launch a 532 nm pulsed laser beam into a square core fiber optical beam delivery system. Further detail will be shared with the experimental performance of the design when integrated within a multi-axis robotic arm, which has six degrees of freedom. These results will include how the fiber injection system improved laser beam stability during process operations, in comparison to traditional simple lens injection methods.

  11. ON ALGORITHMS CREATION FOR STRAPDOWN STABILIZED GYROCOMPASS OPERATION BASED ON ELECTRICALLY SUSPENDED GYROSCOPE

    Directory of Open Access Journals (Sweden)

    Gennady I. Emelyantsev

    2014-09-01

    Full Text Available The paper presents operation algorithms of ESG-based strapdown stabilized gyrocompass (SSGC located onboard a mobile vehicle. Initial alignment mode and calibration of drift model coefficients onboard a vehicle is aided by reference attitude (heading, pitch and roll angles and position data. The required reference attitude parameters can be generated by joint processing of data from MEMS IMU with gyros and accelerometers and GPS compass. Depending on the vehicle dynamics and required accuracy of generated heading, the system may use IMU based on the fiber-optic gyros and accelerometers instead of MEMS to construct the place vertical. Specific features of SSGC algorithms in heading generation are considered. Calibration and corrected operation modes of the system are described. The SSGC uses two ESGs with orthogonal angular momentum vectors, where one gyro is the reference (unit vector of its angular momentum is aligned with the celestial axis and the other one is virtual (with zero misalignments with respect to the inertial frame, and zero drift model coefficients. Joint processing of SSGC data and external position aiding is realized by extended Kalman filter with full-state feedback control. Simulation modeling results of the system operation algorithms are presented. Simulation modeling has confirmed the system compass effect and determined the time required for calibration of ESG with solid-rotor. The results have been applied at «Concern CSRI “Elektropribor”», JSC

  12. Digital signal processing based multi channel analyzer

    International Nuclear Information System (INIS)

    Saklani, Vipin; Meenakshi Sundari, A.; Rai, A.K.; Sarma, C.V.R.

    2013-01-01

    Gamma Ray Spectrometry is an essential tool for mapping radio elemental concentrations and has found widespread applications in mineral exploration, geological mapping and environmental mapping. Spectrometry based on analog amplifiers with Gaussian pulse shaping has been used for more than 40 years. Digital electronics and digital signal processing methods have enhanced the spectrometer specifications. This paper presents the design and development of a FPGA based Gamma Ray Spectrometer featuring 1024 channel Multi Channel Analyser (MCA) with NaI(Tl) scintillation detector. The system shows significant improvements in energy resolution, count rate capability and dead time as compared to its analog counterpart. (author)

  13. Theoretical study of gas and solvent phase stability and molecular adsorption of noncanonical guanine bases on graphene.

    Science.gov (United States)

    Saikia, Nabanita; Karna, Shashi P; Pandey, Ravindra

    2017-06-28

    The gas and solvent phase stability of noncanonical (Gua) n nucleobases is investigated in the framework of dispersion-corrected density functional theory (DFT). The calculated results strongly support the high tendency for the dimerization of (Gua) n bases in both gas and solvent phases. An interplay between intermolecular and bifurcated H-bonds is suggested to govern the stability of (Gua) n bases which bears a correlation with the description of dispersion correction terms employed in the DFT calculations. For example, a higher polarity is predicted for (Gua) n bases by the dispersion-corrected DFT in contrast to the non-polar nature of (Gua) 3 and (Gua) 4 predicted by the hybrid meta-GGA calculations. This distinct variation becomes significant under physiological conditions as polar (Gua) n is likely to exhibit greater stabilization in the gas phase compared to solvated (Gua) n . Graphene acting as a substrate induces modification in base configurations via maximization of π-orbital overlap between the base and substrate. In solvent, the substrate-induced effects are further heightened with lowering of the dipole moments of (Gua) n as also displayed by the corresponding isosurface of the electrostatic potential. The graphene-induced stability in both gas and solvent phases appears to fulfill one of the prerequisite criteria for molecular self-assembly. The DFT results therefore provide atomistic insights into the stability and molecular assembly of free-standing noncanonical (Gua) n nucleobases which can be extended to understanding the self-assembly process of functional biomolecules on 2D materials for potential biosensing applications.

  14. A rapid, ensemble and free energy based method for engineering protein stabilities.

    Science.gov (United States)

    Naganathan, Athi N

    2013-05-02

    Engineering the conformational stabilities of proteins through mutations has immense potential in biotechnological applications. It is, however, an inherently challenging problem given the weak noncovalent nature of the stabilizing interactions. In this regard, we present here a robust and fast strategy to engineer protein stabilities through mutations involving charged residues using a structure-based statistical mechanical model that accounts for the ensemble nature of folding. We validate the method by predicting the absolute changes in stability for 138 experimental mutations from 16 different proteins and enzymes with a correlation of 0.65 and importantly with a success rate of 81%. Multiple point mutants are predicted with a higher success rate (90%) that is validated further by comparing meosphile-thermophile protein pairs. In parallel, we devise a methodology to rapidly engineer mutations in silico which we benchmark against experimental mutations of ubiquitin (correlation of 0.95) and check for its feasibility on a larger therapeutic protein DNase I. We expect the method to be of importance as a first and rapid step to screen for protein mutants with specific stability in the biotechnology industry, in the construction of stability maps at the residue level (i.e., hot spots), and as a robust tool to probe for mutations that enhance the stability of protein-based drugs.

  15. Adaptive Beamforming Based on Complex Quaternion Processes

    Directory of Open Access Journals (Sweden)

    Jian-wu Tao

    2014-01-01

    Full Text Available Motivated by the benefits of array signal processing in quaternion domain, we investigate the problem of adaptive beamforming based on complex quaternion processes in this paper. First, a complex quaternion least-mean squares (CQLMS algorithm is proposed and its performance is analyzed. The CQLMS algorithm is suitable for adaptive beamforming of vector-sensor array. The weight vector update of CQLMS algorithm is derived based on the complex gradient, leading to lower computational complexity. Because the complex quaternion can exhibit the orthogonal structure of an electromagnetic vector-sensor in a natural way, a complex quaternion model in time domain is provided for a 3-component vector-sensor array. And the normalized adaptive beamformer using CQLMS is presented. Finally, simulation results are given to validate the performance of the proposed adaptive beamformer.

  16. Calculation of the Stabilization Energies of Oxidatively Damaged Guanine Base Pairs with Guanine

    Directory of Open Access Journals (Sweden)

    Hiroshi Miyazawa

    2012-06-01

    Full Text Available DNA is constantly exposed to endogenous and exogenous oxidative stresses. Damaged DNA can cause mutations, which may increase the risk of developing cancer and other diseases. G:C-C:G transversions are caused by various oxidative stresses. 2,2,4-Triamino-5(2H-oxazolone (Oz, guanidinohydantoin (Gh/iminoallantoin (Ia and spiro-imino-dihydantoin (Sp are known products of oxidative guanine damage. These damaged bases can base pair with guanine and cause G:C-C:G transversions. In this study, the stabilization energies of these bases paired with guanine were calculated in vacuo and in water. The calculated stabilization energies of the Ia:G base pairs were similar to that of the native C:G base pair, and both bases pairs have three hydrogen bonds. By contrast, the calculated stabilization energies of Gh:G, which form two hydrogen bonds, were lower than the Ia:G base pairs, suggesting that the stabilization energy depends on the number of hydrogen bonds. In addition, the Sp:G base pairs were less stable than the Ia:G base pairs. Furthermore, calculations showed that the Oz:G base pairs were less stable than the Ia:G, Gh:G and Sp:G base pairs, even though experimental results showed that incorporation of guanine opposite Oz is more efficient than that opposite Gh/Ia and Sp.

  17. Stability-indicating assay method for determination of actarit, its process related impurities and degradation products: Insight into stability profile and degradation pathways☆

    Directory of Open Access Journals (Sweden)

    A. Abiramasundari

    2014-12-01

    Full Text Available The stability of the drug actarit was studied under different stress conditions like hydrolysis (acid, alkaline and neutral, oxidation, photolysis and thermal degradation as recommended by International Conference on Harmonization (ICH guidelines. Drug was found to be unstable in acidic, basic and photolytic conditions and produced a common degradation product while oxidative stress condition produced three additional degradation products. Drug was impassive to neutral hydrolysis, dry thermal and accelerated stability conditions. Degradation products were identified, isolated and characterized by different spectroscopic analyses. Drug and the degradation products were synthesized by a new route using green chemistry. The chromatographic separation of the drug and its impurities was achieved in a phenomenex luna C18 column employing a step gradient elution by high performance liquid chromatography coupled to photodiode array and mass spectrometry detectors (HPLC–PDA–MS. A specific and sensitive stability-indicating assay method for the simultaneous determination of the drug actarit, its process related impurities and degradation products was developed and validated. Keywords: Actarit, Forced degradation, Stability-indicating assay method

  18. Electrochemical behaviour of ceramic yttria stabilized zirconia on carbon steel synthesized via sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Crespo, M.A. Dominguez, E-mail: mdominguezc@ipn.m [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira (CICATA-IPN) km 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Murillo, A. Garcia; Torres-Huerta, A.M. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira (CICATA-IPN) km 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Yanez-Zamora, C. [Estudiante del postgrado en Tecnologia Avanzada del CICATA-IPN, Unidad Altamira, km 14.5, Carr. Tampico-Puerto Industrial. C.P. 89600, Altamira, Tamaulipas (Mexico); Carrillo-Romo, F. de J [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Altamira (CICATA-IPN) km 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico)

    2009-08-26

    Chromate conversion coatings have been widely applied for the corrosion of different metallic substrates. However, the waste containing Cr{sup 6+} has many limitations due to the environmental consideration and health hazards. An interesting alternative seems to be the deposition on metallic surface of thin layers of yttria or zirconia or both by the sol-gel process. In this study, Ytttria and Yttria stabilized zirconia (YSZ, 8% Y{sub 2}O{sub 3}) thin films were used for coating commercial carbon steel substrates by sol-gel method and the dip-coating process. The evolution of organic compounds up to crystallization process as a function of heat treatments was study by FT-IR spectroscopy. The structure and morphology of the coatings were analysed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The anticorrosion performance of the coatings has been evaluated by using electrochemical techniques in an aggressive media (3.5 wt.% NaCl). The corrosion behaviour of sol-gel method was compared with traditional chromate conversion coatings. Differences in the electrochemical behaviour of YSZ coatings are related to the development of microcracks during the sintering process and to the presence of organic compounds during growth film. Electrochemical results showed that sol-gel YSZ and Y{sub 2}O{sub 3} coatings can act as protective barriers against wet corrosion; however yttria films displayed low adhesion to substrate. The corrosion parameters provide an explanation of the role of each film and show a considerable increase in the corrosion resistance for coated samples in comparison to the bare steel samples.

  19. Power system stabilizers based on distributed energy resources for damping of inter-area oscillations

    Directory of Open Access Journals (Sweden)

    Stefanov Predrag Č.

    2014-01-01

    Full Text Available This paper deals with inter-area power oscillations damping enhancement by distributed energy resources contained in typical micro grid. Main idea behind this work is to use distributed generation and distributed storage, such as battery energy storage to mimic conventional power system stabilizer, but with regulating active power output, rather than reactive power, as in standard power system stabilizer realization. The analysis of the small signal stability is established for four-machine, two-area system, with inverter based micro grids in each area. Dynamic simulation results are included in this work and they show that proposed controller provides additional damping effect to this test system.

  20. Verification of A Process Based Hydrograph Separation

    Science.gov (United States)

    Fackel, P.; Naef, F.

    Depending on soil structure, geology, topography, etc. runoff during intense precipi- tation is formed either by HOF (Hortonian overland flow), SOF (saturated overland flow), SSF (subsurface flow) or DP (deep percolation). A methodology was developed to delineate the different dominant runoff processes in varying intensities (1 very fast to 3 retarded) in a catchment. In the small Rohr catchment (2.1 km2) the dominant runoff processes were mapped with the help of soil investigations, sprinkling exper- iments, etc.. Also a series of aerial infrared photographs were taken after a heavy rainfall event to observe the drying of the catchment, indicating the extent of satu- rated areas. To verify the mapping we installed a hydrometric measurement network. Discharge was measured form a tile drain system, from areas where only SOF was expected, and from the whole catchment. Shallow groundwater wells were installed in areas where SOF and SSF of different intensities were mapped. Wells on SOF 1 areas showed saturation after 30 mm of precipitation while SOF 2 and 3 soils needed a significantly higher amount of rainfall for saturation. Water levels in wells in SSF areas didnSt rise to ground level even after large amounts of rainfall. Discharge from the SOF areas corresponded well to measured soil saturation. The runoff from the drainage system responded very fast and strong to precipitation, indicating prefer- ential flow through the soil. In a parallel project, the EAWAG investigated pesticide transport in the Rohr catchment. They applied the pesticide atrazine plus a labelling substance to 12 maize fields and measured their concentrations in runoff with a high temporal resolution. Based on the runoff process map the IHW model Qarea simu- lates the contribution of each runoff process to the storm hydrograph separately, thus implicitly yields a process based hydrograph separation. Due to the high spatial reso- lution of the process map it was possible to calculate the spatial

  1. MARKETING STRATEGIES BASED ON THE BUYING PROCESS

    Directory of Open Access Journals (Sweden)

    LIVIU NEAMŢU

    2016-04-01

    Full Text Available In marketing, due to dynamic, rapid and permanent changes known on the market, we will talk more about politics than about strategy, the time horizon covered is much lower than that contained in a classic strategy, with a risk that elements and criteria to which we refer are no longer current. Sales growth strategies are, in fact, combination strategies and consist in the company applying, in its different units, different strategies, according to the requirement of appropriate strategies applied to different environments of action. A business strategy must be based on knowledge of customer purchasing behavior. To contact customers, a company may use one or more specific strategies. Every marketing strategy serves the interest of increasing competitiveness, and of stabilizing and improving the companys position in the market in a highly competitive environment. In the age of transformation into market economy, rapid technological development, and confrontation between economic and ecological factors, every single manager is compelled to elaborate an attitude, and to take a stand concerning research and development, technological transfer, the technological level of products, and the quality of services, because these are the factors determining the future development, the chances of survival, and in a wider sense the objectives of marketing strategy.

  2. Reproducibility and stability of C60 based organic field effect transistor

    Science.gov (United States)

    Ahmed, Rizwan; Sams, Michael; Simbrunner, Clemens; Ullah, Mujeeb; Rehman, Kamila; Schwabegger, Günther; Sitter, H.; Ostermann, Timm

    2012-01-01

    A comprehensive study concerning the reproducibility and stability of organic n-type field effect transistors is presented. C60 based OFETs were chosen to investigate the fabrication reproducibility and the long term stability because C60 is a high mobility n-type material. We fabricated 48 transistors and each transistor was measured for 24 h inside the glove box. To test for life time stability – long term measurements up to three months have been undertaken. We report about the fluctuations in the device parameters of all investigated transistors by comparing the transfer characteristics, and on/off ratio for short time and long time measurements. C60 based OFETs showed good reproducibility and stability for short time measurements and a decay for long time measurements. PMID:22368321

  3. Digital Image Stabilization Method Based on Variational Mode Decomposition and Relative Entropy

    Directory of Open Access Journals (Sweden)

    Duo Hao

    2017-11-01

    Full Text Available Cameras mounted on vehicles frequently suffer from image shake due to the vehicles’ motions. To remove jitter motions and preserve intentional motions, a hybrid digital image stabilization method is proposed that uses variational mode decomposition (VMD and relative entropy (RE. In this paper, the global motion vector (GMV is initially decomposed into several narrow-banded modes by VMD. REs, which exhibit the difference of probability distribution between two modes, are then calculated to identify the intentional and jitter motion modes. Finally, the summation of the jitter motion modes constitutes jitter motions, whereas the subtraction of the resulting sum from the GMV represents the intentional motions. The proposed stabilization method is compared with several known methods, namely, medium filter (MF, Kalman filter (KF, wavelet decomposition (MD method, empirical mode decomposition (EMD-based method, and enhanced EMD-based method, to evaluate stabilization performance. Experimental results show that the proposed method outperforms the other stabilization methods.

  4. Testing the effect of a microbial-based soil amendment on aggregate stability and erodibility

    DEFF Research Database (Denmark)

    Malozo, Mponda; Iversen, Bo Vangsø; Heckrath, Goswin Johann

    Minimizing soil erosion is essential for maintaining proper soil quality and thus preserving soil productivity. The erodibility of a soil is closely linked to its structural stability as well as its infiltrability. This study focuses on testing the effect of two different soil amendments on soil...... aggregate stability and erodibility. Two commercial products, gypsum and a microbial-based solution were used for the experiment and were tested on two Danish sandy loamy soils as well on a sandy soil from Tanzania. The carrier of the microbial-based product, a glycerol solution, was tested as well....... In the laboratory, soils were treated with the soil amendments in a two-step procedure at controlled water contents following aerobic incubation in closed containers. Water-aggregate stability and clay dispersion were measured on soil aggregates less than 8 mm in diameter. Aggregate stability was measured...

  5. Self-Referential Processing in Adolescents: Stability of Behavioral and Event-Related Potential Markers

    Science.gov (United States)

    Auerbach, Randy P.; Bondy, Erin; Stanton, Colin H.; Webb, Christian A.; Shankman, Stewart A.; Pizzagalli, Diego A.

    2016-01-01

    The self-referential encoding task (SRET)—an implicit measure of self-schema—has been used widely to probe cognitive biases associated with depression, including among adolescents. However, research testing the stability of behavioral and electrocortical effects is sparse. Therefore, the current study sought to evaluate the stability of behavioral markers and event-related potentials (ERP) elicited from the SRET over time in healthy, female adolescents (n = 31). At baseline, participants were administered a diagnostic interview and a self-report measure of depression severity. In addition, they completed the SRET while 128-channel event-related potential (ERP) data were recorded to examine early (P1) and late (late positive potential [LPP]) ERPs. Three months later, participants were re-administered the depression self-report measure and the SRET in conjunction with ERPs. Results revealed that healthy adolescents endorsed, recalled, and recognized more positive and fewer negative words at each assessment, and these effects were stable over time (rs = 0.44–0.83). Similarly, they reported a faster reaction time when endorsing self-relevant positive words, as opposed to negative words, at both the initial and follow-up assessment (r = 0.82). Second, ERP responses, specifically potentiated P1 and late LPP positivity to positive versus negative words, were consistent over time (rs = 0.56–0.83), and the internal reliability of ERPs were robust at each time point (rs = 0.52–0.80). As a whole, these medium-to-large effects suggest that the SRET is a reliable behavioral and neural probe of self-referential processing. PMID:27302282

  6. Anaerobic digestion of food waste stabilized by lime mud from papermaking process.

    Science.gov (United States)

    Zhang, Jishi; Wang, Qinqing; Zheng, Pengwei; Wang, Yusong

    2014-10-01

    The effects of lime mud from papermaking process (LMP) addition as buffer agent and inorganic nutrient on the anaerobic digestion stability of food waste (FW) were investigated under mesophilic conditions with the aim of avoiding volatile fatty acids accumulation, and inorganic elements deficiency. When LMP concentration ranged from 6.0 to 10g/L, the FW anaerobic digestion could maintain efficient and stable state. These advantages are attributed to the existence of Ca, Na, Mg, K, Fe, and alkaline substances that favor the methanogenic process. The highest CH4 yield of 272.8mL/g-VS was obtained at LMP and VS concentrations of 10.0 and 19.8g/L, respectively, with the corresponding lag-phase time of 3.84d and final pH of 8.4. The methanogens from residue digestates mainly consisted of Methanobrevibacter, coccus-type and sarcina-type methanogens with LMP addition compared to Methanobacteria in control. However, higher concentration of LMP inhibited methanogenic activities and methane production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. USING THE SULFUR POLYMER STABILIZATION SOLIDIFICATION PROCESS TO TREAT RESIDUAL MERCURY WASTES FROM GOLD MINING OPERATIONS.

    Energy Technology Data Exchange (ETDEWEB)

    BOWERMAN,B.ADAMS,J.KALB,P.WAN,R.Y.LEVIER,M.

    2003-02-24

    Large quantities of mercury are generated as a by-product during the processing of gold ore following mining operations. Newmont Mining Corporation (NMC), which operates some of the world's largest gold mines, sought a method to permanently ''retire'' its mercury by-products, thereby avoiding potential environmental liability. Sulfur Polymer Stabilization-Solidification (SPSS) is an innovative technology developed at Brookhaven National Laboratory (BNL) for treatment of mercury and mercury contaminated materials, such as soil, sludge and debris. BNL conducted a treatability study to determine the potential applicability of SPSS for treatment of Newmont mercury, and the treated product passed the U.S. Environmental Protection Agency (EPA) test for toxicity. The SPSS process has been shown to be effective on radioactive and nonradioactive mercury and mercury-contaminated materials with a pilot-scale batch system capable of producing 0.03 m{sup 3} (1 ft{sup 3}) per batch. Engineering scale-up issues are discussed and material property tests addressing these issues are described.

  8. Phycocyanin stability in microcapsules processed by spray drying method using different inlet temperature

    Science.gov (United States)

    Purnamayati, L.; Dewi, EN; Kurniasih, R. A.

    2018-02-01

    Phycocyanin is natural blue colorant which easily damages by heat. The inlet temperature of spray dryer is an important parameter representing the feature of the microcapsules.The aim of this study was to investigate the phycocyanin stability of microcapsules made from Spirulina sp with maltodextrin and κ-Carrageenan as the coating material, processed by spray drying method in different inlet temperature. Microcapsules were processed in three various inlet temperaturei.e. 90°C, 110°C, and 130°C, respectively. The results indicated that phycocyanin microcapsule with 90°C of inlet temperature produced the highest moisture content, phycocyanin concentration and encapsulation efficiency of 3,5%, 1,729% and 29,623%, respectively. On the other hand, the highest encapsulation yield was produced by 130°C of theinlet temperature of 29,48% and not significantly different with 110°C. The results of Scanning Electron Microscopy (SEM) showed that phycocyanin microcapsules with 110°C of inlet temperature produced the most rounded shape. To sum up, 110°C was the best inlet temperature to phycocyanin microencapsulation by the spray dryer.

  9. Global stability-based design optimization of truss structures using ...

    Indian Academy of Sciences (India)

    Furthermore, a pure pareto-ranking based multi-objective optimization model is employed for the design optimization of the truss structure with multiple objectives. The computational performance of the optimization model is increased by implementing an island model into its evolutionary search mechanism. The proposed ...

  10. Stability of RNA silencing-based traits after virus infection

    DEFF Research Database (Denmark)

    Jørgensen, Bodil; Albrechtsen, Merete

    2007-01-01

    with constructs based on virus coat protein (CP) genes or other viral genes has been successfully used to engineer PTGS-mediated virus resistance into a large number of crop plants and some transgenic lines have been commercially exploited. However the discovery that plant viruses encode suppressors of gene...

  11. Stabilizing cinder gravels for heavily trafficked base course ...

    African Journals Online (AJOL)

    The results of the investigation indicated that the optimum amount of cement required to achieve the minimum UCS of 3.0 MPa as specified in ERA and AACRA pavement design standards for heavily trafficked base course without adding fine soils is found to be 7% cement. However, this high cement requirement was ...

  12. Structures and stabilities of small DNA dumbbells with Watson-Crick and Hoogsteen base pairs.

    Science.gov (United States)

    Escaja, Nuria; Gómez-Pinto, Irene; Rico, Manuel; Pedroso, Enrique; González, Carlos

    2003-07-07

    The structures and stabilities of cyclic DNA octamers of different sequences have been studied by NMR and CD spectroscopy and by restrained molecular dynamics. At low oligonucleotide concentrations, some of these molecules form stable monomeric structures consisting of a short stem of two base pairs connected by two mini-loops of two residues. To our knowledge, these dumbbell-like structures are the smallest observed to date. The relative stabilities of these cyclic dumbbells have been established by studying their melting transitions. Dumbbells made up purely of GC stems are more stable than those consisting purely of AT base pairs. The order of the base pairs closing the loops also has an important effect on the stabilities of these structures. The NMR data indicate that there are significant differences between the solution structures of dumbbells with G-C base pairs in the stem compared to those with A-T base pairs. In the case of dumbbells with G-C base pairs, the residues in the stem form a short segment of a BDNA helix stabilized by two Watson-Crick base pairs. In contrast, in the case of d, the stem is formed by two A-T base pairs with the glycosidic angles of the adenine bases in a syn conformation, most probably forming Hoogsteen base pairs. Although the conformations of the loop residues are not very well defined, the thymine residues at the first position of the loop are observed to fold back into the minor groove of the stem.

  13. Robust Stability Clearance of Flight Control Law Based on Global Sensitivity Analysis

    OpenAIRE

    Ou, Liuli; Liu, Lei; Dong, Shuai; Wang, Yongji

    2014-01-01

    To validate the robust stability of the flight control system of hypersonic flight vehicle, which suffers from a large number of parametrical uncertainties, a new clearance framework based on structural singular value ( $\\mu $ ) theory and global uncertainty sensitivity analysis (SA) is proposed. In this framework, SA serves as the preprocess of uncertain model to be analysed to help engineers to determine which uncertainties affect the stability of the closed loop system more slightly. By ig...

  14. Antioxidant activity and polyphenolic compound stability of lentil-orange peel powder blend in an extrusion process.

    Science.gov (United States)

    Rathod, Rahul P; Annapure, Uday S

    2017-03-01

    Lentil contains substantial amount of protein, carbohydrate, fibre and other nutrients and orange peels powder rich in carbohydrate and fiber content The present study was aimed to investigate the effects of extrusion processing parameter on the level of total phenolic content (TPC), total flavonoid content (TFC), total tannin content and antioxidant activity of lentil-orange peel powder blend, also to investigate the possibility of blend as a candidate for production of protein rich extruded product by using response surface methodology. It was observed that, the physicochemical properties and sensory characteristics of lentil-orange peel based extrudate were highly dependent on process variables. The blend of lentil and orange peel powder has a huge potential for extrusion to produce ready-to-eat extruded with good acceptance. The overall best quality product was optimized and obtained at 16% moisture, 150 °C die temperature and 200 rpm screw speed. Extrusion process increased nutritional value of extruded product with TPC and TFC of 70.4 and 67.62% respectively and antioxidant activity of 60.6%. It showed higher stability at 150 °C with intermediate feed moisture content and despite the use of high temperatures in the extrusion-cooking is possible to minimize the loss of bioactive compounds to achieve products. Thus, results indicated that blend of lentil and orange peel may be used as raw material for the production of extruded snacks with great nutritional value.

  15. Cyclodextrin-grafted barium titanate nanoparticles for improved dispersion and stabilization in water-based systems

    Science.gov (United States)

    Serra-Gómez, R.; Martinez-Tarifa, J. M.; González-Benito, J.; González-Gaitano, G.

    2016-01-01

    Ceramic nanoparticles with piezoelectric properties, such as BaTiO3 (BT), constitute a promising approach in the fields of nanocomposite materials and biomaterials. In the latter case, to be successful in their preparation, the drawback of their fast aggregation and practically null stability in water has to be overcome. The objective of this investigation has been the surface functionalization of BaTiO3 nanoparticles with cyclodextrins (CDs) as a way to break the aggregation and improve the stability of the nanoparticles in water solution, preventing and minimizing their fast precipitation. As a secondary goal, we have achieved extra-functionality of the nanoparticles, bestowed from the hydrophobic cavity of the macrocycle, which is able to lodge guest molecules that can form inclusion complexes with the oligosaccharide. The nanoparticle functionalization has been fully tracked and characterized, and the cytotoxicity of the modified nanoparticles with fibroblasts and pre-osteoblasts cell lines has been assessed with excellent results in a wide range of concentrations. The modified nanoparticles were found to be suitable for the easy preparation of nanocomposite hydrogels, via dispersion in hydrophilic polymers of typical use in biomedical applications (PEG, Pluronics, and PEO), and further processed in the form of films via water casting, showing very good results in terms of homogeneity in the dispersion of the filler. Likewise, as examples of application and with the aim of exploring a different range of nanocomposites, rhodamine B was included in the macrocycles as a model molecule, and films prepared from a thermoplastic matrix (EVA) via high-energy ball milling have been tested by impedance spectroscopy to discuss their dielectric properties, which indicated that even small modifications in the surface of the nanoparticles generate a different kind of interaction with the polymeric matrix. The CD-modified nanoparticles are thus suitable for easy preparation

  16. Cyclodextrin-grafted barium titanate nanoparticles for improved dispersion and stabilization in water-based systems

    Energy Technology Data Exchange (ETDEWEB)

    Serra-Gómez, R. [Universidad de Navarra, Departamento de Química y Edafología (Spain); Martinez-Tarifa, J. M. [Universidad Carlos III de Madrid, Departamento de Ingeniería Eléctrica (Spain); González-Benito, J. [Universidad Carlos III de Madrid, Departamento de Ciencia e Ingeniería de Materiales e Ingeniería Química, IQMAAB (Spain); González-Gaitano, G., E-mail: gaitano@unav.es [Universidad de Navarra, Departamento de Química y Edafología (Spain)

    2016-01-15

    Ceramic nanoparticles with piezoelectric properties, such as BaTiO{sub 3} (BT), constitute a promising approach in the fields of nanocomposite materials and biomaterials. In the latter case, to be successful in their preparation, the drawback of their fast aggregation and practically null stability in water has to be overcome. The objective of this investigation has been the surface functionalization of BaTiO{sub 3} nanoparticles with cyclodextrins (CDs) as a way to break the aggregation and improve the stability of the nanoparticles in water solution, preventing and minimizing their fast precipitation. As a secondary goal, we have achieved extra-functionality of the nanoparticles, bestowed from the hydrophobic cavity of the macrocycle, which is able to lodge guest molecules that can form inclusion complexes with the oligosaccharide. The nanoparticle functionalization has been fully tracked and characterized, and the cytotoxicity of the modified nanoparticles with fibroblasts and pre-osteoblasts cell lines has been assessed with excellent results in a wide range of concentrations. The modified nanoparticles were found to be suitable for the easy preparation of nanocomposite hydrogels, via dispersion in hydrophilic polymers of typical use in biomedical applications (PEG, Pluronics, and PEO), and further processed in the form of films via water casting, showing very good results in terms of homogeneity in the dispersion of the filler. Likewise, as examples of application and with the aim of exploring a different range of nanocomposites, rhodamine B was included in the macrocycles as a model molecule, and films prepared from a thermoplastic matrix (EVA) via high-energy ball milling have been tested by impedance spectroscopy to discuss their dielectric properties, which indicated that even small modifications in the surface of the nanoparticles generate a different kind of interaction with the polymeric matrix. The CD-modified nanoparticles are thus suitable for easy

  17. Model-based characterization of ventilatory stability using spontaneous breathing

    OpenAIRE

    Nemati, Shamim; Edwards, Bradley A.; Sands, Scott A.; Berger, Philip J.; Wellman, Andrew; Verghese, George C.; Malhotra, Atul; Butler, James P.

    2011-01-01

    Cyclic ventilatory instabilities are widely attributed to an increase in the sensitivity or loop gain of the chemoreflex feedback loop controlling ventilation. A major limitation in the conventional characterization of this feedback loop is the need for labor-intensive methodologies. To overcome this limitation, we developed a method based on trivariate autoregressive modeling using ventilation, end-tidal Pco2 and Po2; this method provides for estimation of the overall “loop gain” of the resp...

  18. Pyroprotein-Based Electronic Textiles with High Stability.

    Science.gov (United States)

    Jeon, Jun Woo; Cho, Se Youn; Jeong, Yu Jin; Shin, Dong Seok; Kim, Na Rae; Yun, Young Soo; Kim, Hyun-Tae; Choi, Soo Bong; Hong, Won G; Kim, Hae Jin; Jin, Hyoung-Joon; Kim, Byung Hoon

    2017-02-01

    Thermally reducible pyroprotein-based electronic textiles (e-textiles) are fabricated using graphene oxide and a pyroprotein such as cocoon silk and spider web without any chemical agents. The electrical conductivity of the e-textile is 11.63 S cm -1 , which is maintained even in bending, washing, and temperature variation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. SU-C-204-03: DFT Calculations of the Stability of DOTA-Based-Radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Khabibullin, A.R.; Woods, L.M. [University of South Florida, Tampa, Florida (United States); Karolak, A.; Budzevich, M.M.; Martinez, M.V. [H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida (United States); McLaughlin, M.L.; Morse, D.L. [University of South Florida, Tampa, Florida (United States); H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida (United States)

    2016-06-15

    Purpose: Application of the density function theory (DFT) to investigate the structural stability of complexes applied in cancer therapy consisting of the 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelated to Ac225, Fr221, At217, Bi213, and Gd68 radio-nuclei. Methods: The possibility to deliver a toxic payload directly to tumor cells is a highly desirable aim in targeted alpha particle therapy. The estimation of bond stability between radioactive atoms and the DOTA chelating agent is the key element in understanding the foundations of this delivery process. Thus, we adapted the Vienna Ab-initio Simulation Package (VASP) with the projector-augmented wave method and a plane-wave basis set in order to study the stability and electronic properties of DOTA ligand chelated to radioactive isotopes. In order to count for the relativistic effect of radioactive isotopes we included Spin-Orbit Coupling (SOC) in the DFT calculations. Five DOTA complex structures were represented as unit cells, each containing 58 atoms. The energy optimization was performed for all structures prior to calculations of electronic properties. Binding energies, electron localization functions as well as bond lengths between atoms were estimated. Results: Calculated binding energies for DOTA-radioactive atom systems were −17.792, −5.784, −8.872, −13.305, −18.467 eV for Ac, Fr, At, Bi and Gd complexes respectively. The displacements of isotopes in DOTA cages were estimated from the variations in bond lengths, which were within 2.32–3.75 angstroms. The detailed representation of chemical bonding in all complexes was obtained with the Electron Localization Function (ELF). Conclusion: DOTA-Gd, DOTA-Ac and DOTA-Bi were the most stable structures in the group. Inclusion of SOC had a significant role in the improvement of DFT calculation accuracy for heavy radioactive atoms. Our approach is found to be proper for the investigation of structures with DOTA-based

  20. Stability of the Trichothecene, Deoxynivalenol in Processed Foods and Wheat Flake Cereal

    Science.gov (United States)

    Deoxynivalenol (DON) is a trichothecene mycotoxin produced by Fusarium species, principally F. graminearum and F. culmorum. These fungi are natural contaminants of wheat, barley and corn and, consequently, DON is found in cereal-based foods. The effect of thermal processing on DON is variable: som...

  1. Carbon Fibers from UV-Assisted Stabilization of Lignin-Based Precursors

    Directory of Open Access Journals (Sweden)

    Meng Zhang

    2015-06-01

    Full Text Available Production of high strength carbon fibers from bio-derived precursors is of topical interest. Recently, we reported on dry-spinning of a partially acetylated softwood kraft lignin to produce carbon fibers with superior properties, but the thermo-oxidative stabilization step required a long time due to a slow heating rate needed to prevent the fibers from being heated too rapidly and sticking to each other. Here we report a rapid strategy of dual UV-thermoxidative stabilization (crosslinking of dry-spun lignin fibers that significantly reduces the stabilization time. The fibers undergo reaction close to the surface such that they can be subsequently thermally stabilized at a rapid heating rate without fibers fusing together, which reduces the total stabilization time significantly from 40 to 4 h. Consequently, the glass transition temperature of UV irradiated fibers was about 15 °C higher than that of fibers without UV treatment. Stabilized fibers were successfully carbonized at 1000 °C and resulting carbon fibers displayed a tensile strength of 900 ± 100 MPa, which is amongst the highest reported for carbon fibers derived from softwood lignin-based precursors. These results establish that UV irradiation is a rapid step that can effectively shorten the total stabilization time for production of lignin-derived carbon fibers.

  2. Stability and change in forest-based communities: a selected bibliography.

    Science.gov (United States)

    Catherine Woods Richardson

    1996-01-01

    This bibliography lists literature dealing with the concept of community stability, the condition of forest-based communities, and the relations between forest management and local community conditions. Most citations are from the 1970s to the mid 1990s, though some particularly pertinent earlier works also appear. The emphasis is on forest-based communities in the...

  3. Luminescent Stability of Hybrids Based on Different Borate Glass Matrix’s and Organic Metal Complexes

    Science.gov (United States)

    Petrova, Olga; Avetisov, Roman; Akkuzina, Alina; Anurova, Mariia; Mozhevitina, Elena; Khomyakov, Andrew; Taydakov, Ilya; Avetissov, Igor

    2017-08-01

    The stability of the luminescent properties of new hybrid materials based on 8-oxyquinoline metal (Li, Rb, Sr) complexes and Eu complex with phenanthroline and low-melting Pb-based inorganic glass matrixes under conditions of prolonged exposure under ambient conditions and heating above the glass transition temperature of the matrix’s has been investigated.

  4. Comparison of model reference and map based control method for vehicle stability enhancement

    NARCIS (Netherlands)

    Baek, S.; Son, M.; Song, J.; Boo, K.; Kim, H.

    2012-01-01

    A map based controller method to improve a vehicle lateral stability is proposed in this study and compared with the conventional method, a model referenced controller. A model referenced controller to determine compensated yaw moment uses the sliding mode method, but the proposed map based

  5. Impedance matching based stability criteria for ac microgrids

    Science.gov (United States)

    Mendoza-Araya, Patricio A.

    Well logs, measured in depth, must be tied to seismograms, processed in time, using a time-depth function. Well ties are commonly computed using manual techniques, and are therefore prone to human error. I first introduce an automatic single-well tie method that uses smooth dynamic time warping to compute time shifts that align a synthetic seismogram with a seismic trace. These time shifts are constrained to be smoothly varying. I also show that these well ties, in my example, are insensitive to the complexity of my synthetic seismogram modeling. Tying multiple wells compounds errors in single well ties, and maintaining consistency among multiple single well ties is difficult. I introduce an automatic approach to tying multiple wells that improves consistency among well ties. I first model synthetic seismograms for each well. I then create a synthetic image by interpolating the synthetic seismograms between the wells and along seismic image structure. I use smooth dynamic image warping to align the synthetic image to the seismic image and compute updated time-depth functions for each well. I then interpolate the updated time-depth functions between the wells, and map the time-migrated seismic image to depth.

  6. A salt water battery with high stability and charging rates made from solution processed conjugated polymers with polar side chains

    KAUST Repository

    Moia, Davide

    2017-11-28

    We report a neutral salt water based battery which uses p-type and n-type solution processed polymer films as the cathode and the anode of the cell. The specific capacity of the electrodes (approximately 30 mAh cm-3) is achieved via formation of bipolarons in both the p-type and n-type polymers. By engineering ethylene glycol and zwitterion based side chains attached to the polymer backbone we facilitate rapid ion transport through the non-porous polymer films. This, combined with efficient transport of electronic charge via the conjugated polymer backbones, allowed the films to maintain constant capacity at high charge and discharge rates (>1000 C-rate). The electrodes also show good stability during electrochemical cycling (less than 30% decrease in capacity over >1000 cycles) and an output voltage up to 1.4 V. The performance of these semiconducting polymers with polar side-chains demonstrates the potential of this material class for fast-charging, water based electrochemical energy storage devices.

  7. Agents-based distributed processes control systems

    Directory of Open Access Journals (Sweden)

    Adrian Gligor

    2011-12-01

    Full Text Available Large industrial distributed systems have revealed a remarkable development in recent years. We may note an increase of their structural and functional complexity, at the same time with those on requirements side. These are some reasons why there are involvednumerous researches, energy and resources to solve problems related to these types of systems. The paper addresses the issue of industrial distributed systems with special attention being given to the distributed industrial processes control systems. A solution for a distributed process control system based on mobile intelligent agents is presented.The main objective of the proposed system is to provide an optimal solution in terms of costs, maintenance, reliability and flexibility. The paper focuses on requirements, architecture, functionality and advantages brought by the proposed solution.

  8. Stability evaluation of short-circuiting gas metal arc welding based on ensemble empirical mode decomposition

    Science.gov (United States)

    Huang, Yong; Wang, Kehong; Zhou, Zhilan; Zhou, Xiaoxiao; Fang, Jimi

    2017-03-01

    The arc of gas metal arc welding (GMAW) contains abundant information about its stability and droplet transition, which can be effectively characterized by extracting the arc electrical signals. In this study, ensemble empirical mode decomposition (EEMD) was used to evaluate the stability of electrical current signals. The welding electrical signals were first decomposed by EEMD, and then transformed to a Hilbert-Huang spectrum and a marginal spectrum. The marginal spectrum is an approximate distribution of amplitude with frequency of signals, and can be described by a marginal index. Analysis of various welding process parameters showed that the marginal index of current signals increased when the welding process was more stable, and vice versa. Thus EEMD combined with the marginal index can effectively uncover the stability and droplet transition of GMAW.

  9. EHPS Handling Stability Analysis of Electric Bus Based on System Identification Method

    Science.gov (United States)

    Zhang, Ni; Liu, Hai-mei; Bei, Shao-yi; Li, Bo; Zhao, Jing-bo

    2017-09-01

    Electric hydraulic assist force steering system (EHPS system) is the steering system of electric bus, this paper presents a method of EHPS handling stability analysis based on system identification method according to the handling stability of EHPS system for electric bus. The simulation model of electro-hydraulic assist force steering system EHPS is established by using the software AMESim, and making a quantitative analysis on the characteristics of the electric assist force assisted steering system, the assist force response and stability. At the same time, we study the stability of vehicle, including hunting, transient response, return experiment, the results show that the HPS and EHPS by comparing the simulation: It improves the portability, road sense, transient response and return performance after loading the system, which verifiy the effectiveness of the control strategy that improves vehicle steering performance, and it provides the basis for the optimization of control methods in the future.

  10. Synthesis and evaluation of copolymer based on cardanol and styrene on the stability of asphaltenes

    International Nuclear Information System (INIS)

    Loureiro, Tatiana S.; Spinelli, Luciana S.

    2015-01-01

    The destabilization of asphaltenes in crude oil mainly happens due to variations in pressure, temperature and oil composition, causing significant losses. Polymers containing specific groups can be used as asphaltenes stabilizers and thus, avoid your precipitation, or as asphaltenes flocculants to assist the removal of suspended particles in a particular oil. The monitoring of asphaltenes precipitation is usually evaluated by tests with variation in stability of asphaltenes in function of adding a flocculant solvent. In this work, it was evaluated the influence of a synthesized copolymer based on cardanol and styrene on the stability of asphaltenes. The stability of asphaltenes was monitored by precipitation tests induced by a flocculant agent (n-heptane), using an ultraviolet-visible (UV-Vis) spectrometer. The structural characterization of copolymer was performed by FTIR and 1 H NMR. The results showed that copolymer can act as asphaltene flocculant. (author)

  11. Power System Stabilizer Design Based on a Particle Swarm Optimization Multiobjective Function Implemented Under Graphical Interface

    Directory of Open Access Journals (Sweden)

    Ghouraf Djamel Eddine

    2016-05-01

    Full Text Available Power system stability considered a necessary condition for normal functioning of an electrical network. The role of regulation and control systems is to ensure that stability by determining the essential elements that influence it. This paper proposes a Particle Swarm Optimization (PSO based multiobjective function to tuning optimal parameters of Power System Stabilizer (PSS; this later is used as auxiliary to generator excitation system in order to damp electro mechanicals oscillations of the rotor and consequently improve Power system stability. The computer simulation results obtained by developed graphical user interface (GUI have proved the efficiency of PSS optimized by a Particle Swarm Optimization, in comparison with a conventional PSS, showing stable   system   responses   almost   insensitive   to   large parameter variations.Our present study was performed using a GUI realized under MATLAB in our work.

  12. Hygienic quality of traditional processing and stability of tomato (Lycopersicon esculentum) puree in Togo.

    Science.gov (United States)

    Ameyapoh, Yaovi; de Souza, Comlan; Traore, Alfred S

    2008-09-01

    Microbiological and physicochemical qualities of a tomato (Lycopersicon esculentum) puree production line (ripe tomato, washing, cutting, pounding, bleaching, straining, bottling and pasteurization) and its preservation in Togo, West Africa, were studied using the HACCP method. Samples generated during the steps described previously were analyzed by determining sensory, chemical and microbiological characteristics. Samples were analyzed using MPN for coliform populations and plate count methodology for other bacteria. The microorganisms involved in spoilage of the opened products were moulds of genera Penicillium, Aspergillus, Fusarium, Geotrichum, Mucor and gram-positive Bacillus bacteria. The preserved tomato puree exhibited a pH value of 4.3, 90% water content, 0.98 water activity (aw) and an average ascorbic acid level of 27.3mg/100g. Results showed that the critical control point (CCP) of this tomato puree processing line is the pasteurization stage. The analysis of selected microbiological and physicochemical parameters during the preservation of bottled tomato puree indicated that this product was stable over 22 months at 29 degrees C. But the stability of the opened product stored at 29 degrees C did not exceed two months.

  13. Physical modeling of stabilization water processes of reverse cooling system the thermal power plant

    Science.gov (United States)

    Vlasov, S. M.; Chichirov, A. A.; Chichirova, N. D.; Filimonova, A. A.; Vinogradov, A. S.

    2017-11-01

    The system of reverse cooling is an integral part of combined heat and power plant and, respectively, demands constant control and regulation of structure and the number of deposits from circulating water for maintenance of the steady mode of equipment. Insufficient circulating water processing turns into a big internal problem for combined heat and power plant work and is a source of heat exchange, surfaces pollution sludge formation in device channels, equipment corrosion, biological fouling, biosludge formation, etc. Depending on the reverse cooling functioning at combined heat and power plant various problems demanding accurately differentiated approach to the decision are identified. Various criteria allowing to define existence and intensity of deposits and ways of fight against the formed deposits and equipment corrosion are offered. For each type of reverse cooling system the possible reasons of deposits formation on the heatpower equipment are analyzed and physical and chemical methods for circulating water stabilization are described. These methods safe water treatment installation modes in a case of the interfaced reverse cooling system and provide the minimum quantity of drains in a case with not interfaced system.

  14. Microencapsulate Aspergillus niger peptidases from agroindustrial waste wheat bran: spray process evaluation and stability.

    Science.gov (United States)

    Cabral, T P F; Bellini, N C; Assis, K R; Teixeira, C C C; Lanchote, A D; Cabral, H; Freitas, L A P

    2017-09-01

    The aim of this work was to obtain microencapsulated stable Aspergillus niger peptidases by post fermentation spray drying. The enzymatic extract was evaluated before and after spray drying microencapsulation to verify the effects of five different process parameters on the extract enzymatic activity, i.e. air flow, extract feed rate, drying temperature, homogenising time and weight ratio of extract to encapsulation material. The optimal conditions were determined by desirability functions and experimentally confirmed. Additionally, the stability of the microparticles was assessed during 60 days at 4 °C, 25 °C and 40 °C. The results revealed that the microparticles stored at 4 °C retained approximately 100% of their proteolytic activity at nine days of storage. Considering the industrial adaptation of the bioprocess and the prospect of commercial application of the proteases, the evaluation of different parameters for drying enzymes is required as a valuable alternative to obtain biotechnological products with high added value.

  15. Microstructure stability: Optimisation of 263 Ni-based superalloy

    Directory of Open Access Journals (Sweden)

    Crozet Coraline

    2014-01-01

    Full Text Available To reduce CO2 emissions on coal-fired power plant, A-ultra supercritical (A-USC power plant whose steam conditions exceed 700 °C are being developed. At these elevated temperatures, the use of Ni-base superalloys becomes necessary. In this context and within the European project NextGenPower, focus is made on commercial Nimonic C-263 as a candidate material for turbine rotors. Nimonic C-263 is known to have low sensitivity to segregation, high workability and high weldability which are major properties for the manufacture of large shafts. Long-term creep strength is also required for this application and unfortunately Nimonic C-263 shows η-phase precipitation after long-time exposure between 700 °C–900 °C which is detrimental for long-term creep properties. The composition of Nimonic C-263 was thus optimised to overcome the formation of η-phase. Trial tests were made in order to study the effect of hardening contribution elements on microstructural and mechanical properties. Then, a 500 mm diameter forged rotor was made from optimised 263 alloy and shows promising properties.

  16. Convergence and Heterogeneity in Euro Based Economies: Stability and Dynamics

    Directory of Open Access Journals (Sweden)

    Philip Haynes

    2016-08-01

    Full Text Available Cluster analysis is used to explore the performance of key macroeconomic variables in European countries that share the euro, from the inception of the currency in 2002 through to 2013. An original applied statistical approach searches for a pattern synthesis across a matrix of macroeconomic data to examine if there is evidence for country clusters and whether there is convergence of the cluster patterns over time. A number of different clusters appear and these change over time as the economies of the member states dynamically interact. This includes some new countries joining the currency during the period of examination. As found in previous research, Southern European countries tend to remain separate from other countries. The new methods used, however, add to an understanding of some differences between Southern European countries, in addition to replicating their broad similarities. Hypotheses are formed about the country clusters existing in 2002, 2006 and 2013, at key points in time of the euro integration process. These hypotheses are tested using the rigour of a bivariate analysis and the multivariate method of Qualitative Comparative Analysis (QCA. The results confirm the hypotheses of cluster memberships in all three periods. The confirmation analysis provides evidence about which variables are most influencing cluster memberships at each time point. In 2002 and 2006, differences between countries are influenced by their different Harmonised Index of Consumer Prices (HICP and labour productivity scores. In 2013, after the crisis, there is a noticeable change. Long term interest rates and gross government debt become key determinants of differences, in addition to the continuing influence of labour productivity. The paper concludes that in the last decade the convergence of countries sharing the euro has been limited, by the joining of new countries and the circumstances of the global economic crisis. The financial crisis has driven

  17. Investigation of the microbial community structure and activity as indicators of compost stability and composting process evolution.

    Science.gov (United States)

    Chroni, Christina; Kyriacou, Adamadini; Manios, Thrassyvoulos; Lasaridi, Konstantia-Ekaterini

    2009-08-01

    In a bid to identify suitable microbial indicators of compost stability, the process evolution during windrow composting of poultry manure (PM), green waste (GW) and biowaste was studied. Treatments were monitored with regard to abiotic factors, respiration activity (determined using the SOUR test) and functional microflora. The composting process went through typical changes in temperature, moisture content and microbial properties, despite the inherent feedstock differences. Nitrobacter and pathogen indicators varied as a monotonous function of processing time. Some microbial groups have shown a potential to serve as fingerprints of the different process stages, but still they should be examined in context with respirometric tests and abiotic parameters. Respiration activity reflected well the process stage, verifying the value of respirometric tests to access compost stability. SOUR values below 1 mg O(2)/g VS/h were achieved for the PM and the GW compost.

  18. Sensitivity of boundary-layer stability to base-state distortions at high Mach numbers

    Science.gov (United States)

    Park, Junho; Zaki, Tamer

    2017-11-01

    The stability diagram of high-speed boundary layers has been established by evaluating the linear instability modes of the similarity profile, over wide ranges of Reynolds and Mach numbers. In real flows, however, the base state can deviate from the similarity profile. Both the base velocity and temperature can be distorted, for example due to roughness and thermal wall treatments. We review the stability problem of high-speed boundary layer, and derive a new formulation of the sensitivity to base-state distortion using forward and adjoint parabolized stability equations. The new formulation provides qualitative and quantitative interpretations on change in growth rate due to modifications of mean-flow and mean-temperature in heated high-speed boundary layers, and establishes the foundation for future control strategies. This work has been funded by the Air Force Office of Scientific Research (AFOSR) Grant: FA9550-16-1-0103.

  19. Processing of free radical damaged DNA bases

    International Nuclear Information System (INIS)

    Wallace, S.

    2003-01-01

    Free radicals produced during the radiolysis of water gives rise to a plethora of DNA damages including single strand breaks, sites of base loss and a wide variety of purine and pyrimidine base lesions. All these damages are processed in cells by base excision repair. The oxidative DNA glycosylases which catalyze the first step in the removal of a base damage during base excision repair evolved primarily to protect the cells from the deleterious mutagenic effects of single free radical-induced DNA lesions arising during oxidative metabolism. This is evidenced by the high spontaneous mutation rate in bacterial mutants lacking the oxidative DNA glycosylases. However, when a low LET photon transverses the DNA molecule, a burst of free radicals is produced during the radiolysis of water that leads to the formation of clustered damages in the DNA molecule, that are recognized by the oxidative DNA glycosylases. When substrates containing two closely opposed sugar damages or base and sugar damages are incubated with the oxidative DNA glycosylases in vitro, one strand is readily incised by the lyase activity of the DNA glycosylase. Whether or not the second strand is incised depends on the distance between the strand break resulting from the incised first strand and the remaining DNA lesion on the other strand. If the lesions are more than two or three base pairs apart, the second strand is readily cleaved by the DNA glycosylase, giving rise to a double strand break. Even if the entire base excision repair system is reconstituted in vitro, whether or not a double strand break ensues depends solely upon the ability of the DNA glycosylase to cleave the second strand. These data predicted that cells deficient in the oxidative DNA glycosylases would be radioresistant while those that overproduce an oxidative DNA glycosylase would be radiosensitive. This prediction was indeed borne in Escherichia coli that is, mutants lacking the oxidative DNA glycosylases are radioresistant

  20. Generating quantitative models describing the sequence specificity of biological processes with the stabilized matrix method

    Directory of Open Access Journals (Sweden)

    Sette Alessandro

    2005-05-01

    Full Text Available Abstract Background Many processes in molecular biology involve the recognition of short sequences of nucleic-or amino acids, such as the binding of immunogenic peptides to major histocompatibility complex (MHC molecules. From experimental data, a model of the sequence specificity of these processes can be constructed, such as a sequence motif, a scoring matrix or an artificial neural network. The purpose of these models is two-fold. First, they can provide a summary of experimental results, allowing for a deeper understanding of the mechanisms involved in sequence recognition. Second, such models can be used to predict the experimental outcome for yet untested sequences. In the past we reported the development of a method to generate such models called the Stabilized Matrix Method (SMM. This method has been successfully applied to predicting peptide binding to MHC molecules, peptide transport by the transporter associated with antigen presentation (TAP and proteasomal cleavage of protein sequences. Results Herein we report the implementation of the SMM algorithm as a publicly available software package. Specific features determining the type of problems the method is most appropriate for are discussed. Advantageous features of the package are: (1 the output generated is easy to interpret, (2 input and output are both quantitative, (3 specific computational strategies to handle experimental noise are built in, (4 the algorithm is designed to effectively handle bounded experimental data, (5 experimental data from randomized peptide libraries and conventional peptides can easily be combined, and (6 it is possible to incorporate pair interactions between positions of a sequence. Conclusion Making the SMM method publicly available enables bioinformaticians and experimental biologists to easily access it, to compare its performance to other prediction methods, and to extend it to other applications.

  1. Vegetation as a driver of temporal variations in slope stability: The impact of hydrological processes

    Science.gov (United States)

    Kim, John H.; Fourcaud, Thierry; Jourdan, Christophe; Maeght, Jean-Luc; Mao, Zhun; Metayer, James; Meylan, Louise; Pierret, Alain; Rapidel, Bruno; Roupsard, Olivier; de Rouw, Anneke; Sanchez, Mario Villatoro; Wang, Yan; Stokes, Alexia

    2017-05-01

    Although vegetation is increasingly used to mitigate landslide risks, how vegetation affects the temporal variability of slope stability is poorly understood, especially in earthquake-prone regions. We combined 3-year long soil moisture monitoring, measurements of soil physical properties and plant functional traits, and numerical modeling to compare slope stability under paired land uses with and without trees in tropical, subtropical, and temperate landslide- and earthquake-prone regions. Trees improved stability for 5-12 months per year from drawdown of soil moisture and resulted in less interannual variability in the duration of high-stability periods compared to slopes without trees. Our meta-analysis of published data also showed that slopes with woody vegetation were more stable and less sensitive to climate and soil factors than slopes with herbaceous vegetation. However, estimates of earthquake magnitude necessary to destabilize slopes at our sites suggest that large additional stabilization from trees is necessary for meaningful protection against external triggers.

  2. APC fly ashes stabilized with Portland cement for further development of road sub-base aggregates

    Science.gov (United States)

    Formosa, J.; Giro-Paloma, J.; Maldonado-Alameda, A.; Huete-Hernández, S.; Chimenos, J. M.

    2017-10-01

    Although waste-to-energy plants allow reducing the mass and volume of municipal solid waste (MSW) incinerated, an average around 30 % of the total content remains as bottom ash (BA) and air pollution control (APC) ashes at the end of combustion process. While weathered bottom ash (WBA) is considered a non-hazardous residue that can be revalorized as a secondary aggregate, APC fly ashes generated during the flue gas treatment are classified as hazardous waste and are handled in landfill disposal after stabilization, usually with Portland cement (OPC). However, taking into account the amount of APC residues produced and the disposing cost in landfill, their revalorization is an important issue that could be effectively addressed. As MSW can be incinerated producing bottom ashes (BA) or air pollutant control (APC) residues, the development of a mortar formulated with APC fly ash as secondary building material is a significant risk to the environment for their content of heavy metals. In this way, Design of Experiment (DoE) was used for the improvement of granular material (GM) formulation composed by APC and OPC for further uses as road sub-base aggregate. DoE analysis was successful in the modelling and optimization the formulation as function of the mechanical properties and APC amount. Consequently, an optimal mortar formulation (OMF) of around 50 wt.% APC and 50 wt.% OPC was considered. The OMF leachates and abrasion resistance have been analyzed. These results have demonstrated the viability of OMF as non-hazardous material feasible to be used as secondary aggregate. Moreover, it would be possible to consider the environmental assessment of a GM composed by ≈20 wt.% of OMF and ≈80 wt.% of WBA in order to improve mechanical properties and heavy metals stabilization.

  3. The stability of the RNA bases: implications for the origin of life

    Science.gov (United States)

    Levy, M.; Miller, S. L.; Bada, J. L. (Principal Investigator)

    1998-01-01

    High-temperature origin-of-life theories require that the components of the first genetic material are stable. We therefore have measured the half-lives for the decomposition of the nucleobases. They have been found to be short on the geologic time scale. At 100 degreesC, the growth temperatures of the hyperthermophiles, the half-lives are too short to allow for the adequate accumulation of these compounds (t1/2 for A and G approximately 1 yr; U = 12 yr; C = 19 days). Therefore, unless the origin of life took place extremely rapidly (origin of life may be possible, but it cannot involve adenine, uracil, guanine, or cytosine. The rates of hydrolysis at 100 degreesC also suggest that an ocean-boiling asteroid impact would reset the prebiotic clock, requiring prebiotic synthetic processes to begin again. At 0 degreesC, A, U, G, and T appear to be sufficiently stable (t1/2 >/= 10(6) yr) to be involved in a low-temperature origin of life. However, the lack of stability of cytosine at 0 degreesC (t1/2 = 17, 000 yr) raises the possibility that the GC base pair may not have been used in the first genetic material unless life arose quickly (<10(6) yr) after a sterilization event. A two-letter code or an alternative base pair may have been used instead.

  4. Reflex-mediated dynamic neuromuscular stabilization in stroke patients: EMG processing and ultrasound imaging.

    Science.gov (United States)

    Yoon, Hyun S; You, Joshua Sung H

    2017-07-20

    Postural core instability is associated with poor dynamic balance and a high risk of serious falls. Both neurodevelopmental treatment (NDT) and dynamic neuromuscular stabilization (DNS) core stabilization exercises have been used to improve core stability, but the outcomes of these treatments remain unclear. This study was undertaken to examine the therapeutic effects of NDT and DNS core stabilization exercises on muscular activity, core stability, and core muscle thickness. Ten participants (5 healthy adults; 5 hemiparetic stroke patients) were recruited. Surface electromyography (EMG) was used to determine core muscle activity of the transversus abdominis/internal oblique (TrA/IO), external oblique (EO), and rectus abdominis (RA) muscles. Ultrasound imaging was used to measure transversus abdominals/internal oblique (TrA/IO) thickness, and a pressure biofeedback unit (PBU) was used to measure core stability during the DNS and NDT core exercise conditions. Data are reported as median and range and were compared using nonparametric Mann - Whitney U test and Wilcoxon signed rank test at p< 0.05. Both healthy and hemiparetic stroke groups showed greater median EMG amplitude in the TrA/IO muscles, core stability, and muscle thickness values during the DNS exercise condition than during the NDT core exercise condition, respectively (p< 0.05). However, the relative changes in the EMG amplitude, core stability, and muscle thickness values were greater during the DNS exercise condition than during the NDT core exercise condition in the hemiparetic stroke patient group (p< 0.05). Our novel results provide the first clinical evidence that DNS is more effective than NDT in both healthy and hemiparetic stroke subjects to provide superior deep core muscle activation, core stabilization, and muscle thickness. Moreover, such advantageous therapeutic benefits of the DNS core stabilization exercise over the NDT exercise were more apparent in the hemiparetis stroke patients than

  5. Examination of solidified and stabilized matrices as a result of solidification and stabilization process of arseniccontaining sludge with portland cement and lime

    Directory of Open Access Journals (Sweden)

    Tanapon Phenrat

    2004-02-01

    Full Text Available By solidification and stabilization (S/S with Portland cement and lime, it is possible to reduce arsenic concentration in leachate of the arsenic-containing sludge from arsenic removal process by coagulation with ferric chloride. From the initial arsenic concentration in leachate of unsolidified /unstabilized sludge which was around 20.75 mg/L, the arsenic concentrations in leachate of solidified/stabilized waste were reduced to 0.3, 0.58, 1.09, and 1.85 mg/L for the waste-to-binder ratios of 0.15, 0.25, 0.5, and 1, respectively, due tothe formation of insoluble calcium-arsenic compounds. To be more cost effective for the future, alternative uses of these S/S products were also assessed by measurement of compressive strength of the mortar specimens. It was found that the compressive strengths of these matrices were from 28 ksc to 461 ksc. In conclusion, considering compressive strength and leachability of the solidified matrices, some of these solidified/ stabilized products have potential to serve as an interlocking concrete paving block.

  6. Segment Tracking via a Spatiotemporal Linking Process including Feedback Stabilization in an n-D Lattice Model

    Directory of Open Access Journals (Sweden)

    Florentin Wörgötter

    2009-11-01

    Full Text Available Model-free tracking is important for solving tasks such as moving-object tracking and action recognition in cases where no prior object knowledge is available. For this purpose, we extend the concept of spatially synchronous dynamics in spin-lattice models to the spatiotemporal domain to track segments within an image sequence. The method is related to synchronization processes in neural networks and based on superparamagnetic clustering of data. Spin interactions result in the formation of clusters of correlated spins, providing an automatic labeling of corresponding image regions. The algorithm obeys detailed balance. This is an important property as it allows for consistent spin-transfer across subsequent frames, which can be used for segment tracking. Therefore, in the tracking process the correct equilibrium will always be found, which is an important advance as compared with other more heuristic tracking procedures. In the case of long image sequences, i.e., movies, the algorithm is augmented with a feedback mechanism, further stabilizing segment tracking.

  7. Vitrification process for the volume reduction and stabilization of organic resins

    International Nuclear Information System (INIS)

    Buelt, J.L.

    1982-10-01

    Pacific Northwest Laboratory has completed a series of experimental tests sponsored by the US Department of Energy (DOE) to determine the feasibility of incinerating and vitrifying organic ion-exchange resins in a single-step process. The resins used in this study were identical to those used for decontaminating auxiliary building water at the Three Mile Island (TMI) Unit 2 reactor. The primarily organic resins were loaded with nonradioactive isotopes of cesium and strontium for processing in a pilot-scale, joule-heated glass melter modified to support resin combustion. The feasibility tests demonstrated an average process rate of 3.0 kg/h. Based on this rate, if 50 organic resin liners were vitrified in a six-month campaign, a melter 2.5 times the size of the pilot scale unit would be adequate. A maximum achievable volume reduction of 91% was demonstrated in these tests

  8. Nanoemulsions produced with varied type of emulsifier and oil content: An influence of formulation and process parameters on the characteristics and physical stability

    Directory of Open Access Journals (Sweden)

    Đorđević Sanela M.

    2013-01-01

    Full Text Available The aim of the present study was to prepare oil-in-water nanoemulsions stabilized with a novel natural alkyl polyglucoside surfactant and to compare them with corresponding lecithin/polysorbate 80 - based nanoemulsions in terms of physicochemical properties and physical stability. Nanoemulsions were prepared by high pressure homogenization, using 20, 30 and 40% (w/w medium chain triglyceride as oil phase, and 4, 6 and 8% (w/w lecithin/polysorbate 80 mixture (1/1 or caprylyl/capryl glucoside as emulsifiers. The influence of emulsifier type, emulsifier concentration and oil content was investigated with respect to changes in particle size, particle size distribution, surface charge and physical stability. The influence of production parameters (number of homogenization cycles, type of homogenization process, homogenization pressure on particle size was also investigated. Analysis was performed by photon correlation spectroscopy, laser diffraction, zeta potential, pH and electrical conductivity measurements. All formulations produced revealed a small droplet size ranging from 147 to 228 nm and a very narrow size distribution (polydispersity index range 0,072-0,124. Zeta potentials were about -20 mV and -50 mV for nanoemulsions stabilized with lecithin/polysorbate 80 and caprylyl/capryl glucoside, respectively. The results obtained during the stability studies (6 months at 25°C and 1 month at 40°C indicated that nanoemulsion stability was influenced by their composition. Acquired results also suggested the most appropriate production parameters: 9 homogenization cycles, homogenization pressure of 500 bar and discontinuous process of homogenization.

  9. Phenomena based Methodology for Process Synthesis incorporating Process Intensification

    DEFF Research Database (Denmark)

    Lutze, Philip; Babi, Deenesh Kavi; Woodley, John

    2013-01-01

    Process intensification (PI) has the potential to improve existing as well as conceptual processes, in order to achieve a more sustainable production. PI can be achieved at different levels. That is, the unit operations, functional and/or phenomena level. The highest impact is expected by looking...

  10. Study on modulation amplitude stabilization method for PEM based on FPGA in atomic magnetometer

    Science.gov (United States)

    Wang, Qinghua; Quan, Wei; Duan, Lihong

    2017-10-01

    Atomic magnetometer which uses atoms as sensitive elements have ultra-high precision and has wide applications in scientific researches. The photoelastic modulation method based on photoelastic modulator (PEM) is used in the atomic magnetometer to detect the small optical rotation angle of a linearly polarized light. However, the modulation amplitude of the PEM will drift due to the environmental factors, which reduces the precision and long-term stability of the atomic magnetometer. Consequently, stabilizing the PEM's modulation amplitude is essential to precision measurement. In this paper, a modulation amplitude stabilization method for PEM based on Field Programmable Gate Array (FPGA) is proposed. The designed control system contains an optical setup and an electrical part. The optical setup is used to measure the PEM's modulation amplitude. The FPGA chip, with the PID control algorithm implemented in it, is used as the electrical part's micro controller. The closed loop control method based on the photoelastic modulation detection system can directly measure the PEM's modulation amplitude in real time, without increasing the additional optical devices. In addition, the operating speed of the modulation amplitude stabilization control system can be greatly improved because of the FPGA's parallel computing feature, and the PID control algorithm ensures flexibility to meet different needs of the PEM's modulation amplitude set values. The Modelsim simulation results show the correctness of the PID control algorithm, and the long-term stability of the PEM's modulation amplitude reaches 0.35% in a 3-hour continuous measurement.

  11. Nucleophilic stabilization of water-based reactive ink for titania-based thin film inkjet printing

    DEFF Research Database (Denmark)

    Gadea, Christophe; Marani, Debora; Esposito, Vincenzo

    2017-01-01

    -methyldiethanolamine (MDEA) used as nucleophilic ligand. The function of the ligand is to control the fast hydrolysis/condensation reactions in water for the metal alkoxide before deposition, leading to formation of the TiO2 only after the jet process. The evolution of the titanium-ligand interactions at increasing amount......Drop on demand deposition (DoD) of titanium oxide thin films (water-based solution by a combined use of titanium isopropoxide and n...

  12. Multi-objective approach for load shedding based on voltage stability index consideration

    Directory of Open Access Journals (Sweden)

    R. Kanimozhi

    2014-12-01

    Full Text Available In voltage stability analysis, it is useful to assess voltage stability of power systems by means of scalar magnitudes, or indices. Operators can use voltage stability indices to know how close the system to voltage collapse. The voltage stability indices are a powerful tool to identify the weakest bus and critical line. This identification can be used to gain control over devices for voltage stability up to certain level and load shedding is possible if the load keeps on increasing. This paper presents a computationally simple index based load shedding algorithm using weighted sum genetic algorithm where an AC power flow solution cannot be found for the stressed conditions. Minimization of total load shed and sum of New Voltage Stability Index (NVSI at the selected buses are considered as two objectives of this algorithm to restore the power flow solvability. This is validated in both IEEE 30 bus system and a practical system Tamil Nadu Electricity board (TNEB 69 bus system in India for considering both heavy loading and (N − 1 contingency.

  13. Solvent extraction of gold using ionic liquid based process

    Science.gov (United States)

    Makertihartha, I. G. B. N.; Zunita, Megawati; Rizki, Z.; Dharmawijaya, P. T.

    2017-01-01

    In decades, many research and mineral processing industries are using solvent extraction technology for metal ions separation. Solvent extraction technique has been used for the purification of precious metals such as Au and Pd, and base metals such as Cu, Zn and Cd. This process uses organic compounds as solvent. Organic solvents have some undesired properties i.e. toxic, volatile, excessive used, flammable, difficult to recycle, low reusability, low Au recovery, together with the problems related to the disposal of spent extractants and diluents, even the costs associated with these processes are relatively expensive. Therefore, a lot of research have boosted into the development of safe and environmentally friendly process for Au separation. Ionic liquids (ILs) are the potential alternative for gold extraction because they possess several desirable properties, such as a the ability to expanse temperature process up to 300°C, good solvent properties for a wide range of metal ions, high selectivity, low vapor pressures, stability up to 200°C, easy preparation, environmentally friendly (commonly called as "green solvent"), and relatively low cost. This review paper is focused in investigate of some ILs that have the potentials as solvent in extraction of Au from mineral/metal alloy at various conditions (pH, temperature, and pressure). Performances of ILs extraction of Au are studied in depth, i.e. structural relationship of ILs with capability to separate Au from metal ions aggregate. Optimal extraction conditon in order to gain high percent of Au in mineral processing is also investigated.

  14. The Critical Choice of PEDOT: PSS Additives for Long Term Stability of Roll‐to‐Roll Processed OPVs

    DEFF Research Database (Denmark)

    Roth, Bérenger; Benatto, Gisele Alves dos Reis; Corazza, Michael

    2015-01-01

    The impact of additives mixed with poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) on the stability of organic photovoltaic modules is investigated for fully ambient roll-to-roll (R2R) processed indium tin oxide free modules. Four different PEDOT:PSS inks from two different...

  15. Plastibloc, a waste stabilization process with thermoplastic binders; Plastibloc procede de stabilisation des dechets par liants thermoplastiques

    Energy Technology Data Exchange (ETDEWEB)

    Levasseur, J.P.; Seguy, Y. [OTVD, Omnium de Traitements et de Valorisation des Dechets, 94 - Saint-Maurice (France)

    1997-12-31

    The Plastibloc process is used for the stabilization of various toxic wastes, such as municipal waste incineration residues. The residues are extruded, mixed with plastics issued from municipal wastes or common industrial wastes. The long term behaviour of the extruded material is analyzed and tests are reported concerning the ash extraction by water and salt diffusion in the plastic matrix

  16. High calcium fly ash geopolymer stabilized lateritic soil and granulated blast furnace slag blends as a pavement base material.

    Science.gov (United States)

    Phummiphan, Itthikorn; Horpibulsuk, Suksun; Rachan, Runglawan; Arulrajah, Arul; Shen, Shui-Long; Chindaprasirt, Prinya

    2018-01-05

    Granulated Blast Furnace Slag (GBFS) was used as a replacement material in marginal lateritic soil (LS) while class C Fly Ash (FA) was used as a precursor for the geopolymerization process to develop a low-carbon pavement base material at ambient temperature. Unconfined Compression Strength (UCS) tests were performed to investigate the strength development of geopolymer stabilized LS/GBFS blends. Scanning Electron Microscopy and X-ray Diffraction analysis were undertaken to examine the role of the various influencing factors on UCS development. The influencing factors studied included GBFS content, Na 2 SiO 3 :NaOH ratio (NS:NH) and curing time. The 7-day soaked UCS of FA geopolymer stabilized LS/GBFS blends at various NS:NH ratios tested was found to satisfy the specifications of the Thailand national road authorities. The GBFS replacement was found to be insignificant for the improvement of the UCS of FA geopolymer stabilized LS/GBFS blends at low NS:NH ratio of 50:50. Microstructural analysis indicated the coexistence of Calcium Silicate Hydrate (CSH) and Sodium Alumino Silicate Hydrate products in FA geopolymer stabilized LS/GBFS blends. This research enables GBFS, which is traditionally considered as a waste material, to be used as a replacement and partially reactive material in FA geopolymer pavement applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Proportional derivative based stabilizing control of paralleled grid converters with cables in renewable power plants

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    Resonant interactions of grid-connected converters with each other and with cable capacitance are challenging the stability and power quality of renewable energy sources based power plants. This paper addresses the instability of current control of converters with the multiple resonance frequencies...... consisting in LCL filters and cables. Both grid and converter current controls are analyzed. The frequency region, within which the system may be destabilized, is identified by means of the impedance-based stability analysis and frequency-domain passivity theory. A proportional derivative control strategy...... is then proposed to stabilize the system. Simulation case studies on four paralleled grid converters and experimental tests for two paralleled grid converters are carried out to validate the performance of the proposed control....

  18. Sample Entropy-Based Approach to Evaluate the Stability of Double-Wire Pulsed MIG Welding

    Directory of Open Access Journals (Sweden)

    Ping Yao

    2014-01-01

    Full Text Available According to the sample entropy, this paper deals with a quantitative method to evaluate the current stability in double-wire pulsed MIG welding. Firstly, the sample entropy of current signals with different stability but the same parameters is calculated. The results show that the more stable the current, the smaller the value and the standard deviation of sample entropy. Secondly, four parameters, which are pulse width, peak current, base current, and frequency, are selected for four-level three-factor orthogonal experiment. The calculation and analysis of desired signals indicate that sample entropy values are affected by welding current parameters. Then, a quantitative method based on sample entropy is proposed. The experiment results show that the method can preferably quantify the welding current stability.

  19. Remote stabilization of copper paddlewheel based molecular building blocks in metal-organic frameworks

    KAUST Repository

    Gao, Wenyang

    2015-03-24

    Copper paddlewheel based molecular building blocks (MBBs) are ubiquitous and have been widely employed for the construction of highly porous metal-organic frameworks (MOFs). However, most copper paddlewheel based MOFs fail to retain their structural integrity in the presence of water. This instability is directly correlated to the plausible displacement of coordinating carboxylates in the copper paddlewheel MBB, [Cu2(O2C-)4], by the strongly coordinating water molecules. In this comprehensive study, we illustrate the chemical stability control in the rht-MOF platform via strengthening the coordinating bonds within the triangular inorganic MBB, [Cu3O(N4-x(CH)xC-)3] (x = 0, 1, or 2). Remotely, the chemical stabilization propagated into the paddlewheel MBB to afford isoreticular rht-MOFs with remarkably enhanced water/chemical stabilities compared to the prototypal rht-MOF-1. © 2015 American Chemical Society.

  20. Fuzzy wavelet plus a quantum neural network as a design base for power system stability enhancement.

    Science.gov (United States)

    Ganjefar, Soheil; Tofighi, Morteza; Karami, Hamidreza

    2015-11-01

    In this study, we introduce an indirect adaptive fuzzy wavelet neural controller (IAFWNC) as a power system stabilizer to damp inter-area modes of oscillations in a multi-machine power system. Quantum computing is an efficient method for improving the computational efficiency of neural networks, so we developed an identifier based on a quantum neural network (QNN) to train the IAFWNC in the proposed scheme. All of the controller parameters are tuned online based on the Lyapunov stability theory to guarantee the closed-loop stability. A two-machine, two-area power system equipped with a static synchronous series compensator as a series flexible ac transmission system was used to demonstrate the effectiveness of the proposed controller. The simulation and experimental results demonstrated that the proposed IAFWNC scheme can achieve favorable control performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. How to measure ecosystem stability? An evaluation of the reliability of stability metrics based on remote sensing time series across the major global ecosystems.

    Science.gov (United States)

    De Keersmaecker, Wanda; Lhermitte, Stef; Honnay, Olivier; Farifteh, Jamshid; Somers, Ben; Coppin, Pol

    2014-07-01

    Increasing frequency of extreme climate events is likely to impose increased stress on ecosystems and to jeopardize the services that ecosystems provide. Therefore, it is of major importance to assess the effects of extreme climate events on the temporal stability (i.e., the resistance, the resilience, and the variance) of ecosystem properties. Most time series of ecosystem properties are, however, affected by varying data characteristics, uncertainties, and noise, which complicate the comparison of ecosystem stability metrics (ESMs) between locations. Therefore, there is a strong need for a more comprehensive understanding regarding the reliability of stability metrics and how they can be used to compare ecosystem stability globally. The objective of this study was to evaluate the performance of temporal ESMs based on time series of the Moderate Resolution Imaging Spectroradiometer derived Normalized Difference Vegetation Index of 15 global land-cover types. We provide a framework (i) to assess the reliability of ESMs in function of data characteristics, uncertainties and noise and (ii) to integrate reliability estimates in future global ecosystem stability studies against climate disturbances. The performance of our framework was tested through (i) a global ecosystem comparison and (ii) an comparison of ecosystem stability in response to the 2003 drought. The results show the influence of data quality on the accuracy of ecosystem stability. White noise, biased noise, and trends have a stronger effect on the accuracy of stability metrics than the length of the time series, temporal resolution, or amount of missing values. Moreover, we demonstrate the importance of integrating reliability estimates to interpret stability metrics within confidence limits. Based on these confidence limits, other studies dealing with specific ecosystem types or locations can be put into context, and a more reliable assessment of ecosystem stability against environmental disturbances

  2. Color stability of siloranes versus methacrylate-based composites after immersion in staining solutions.

    Science.gov (United States)

    Arocha, Mariana A; Mayoral, Juan R; Lefever, Dorien; Mercade, Montserrat; Basilio, Juan; Roig, Miguel

    2013-07-01

    The purpose of this study was to determine, by using a spectrophotometer device, the color stability of silorane in comparison with four methacrylate-based composites after being immersed in different staining solutions such as coffee, black tea, red wine, orange juice, and coke, and distilled water as control group. Four restorative methacrylate-based composites (Filtek Z250, TetricEvoCeram, Venus Diamond, and Grandio) and one silorane (FiltekSilorane) of shade A2 were selected to measure their color stability (180 disk samples) after 4 weeks of immersion in six staining solutions: black tea, coffee, red wine, orange juice, coke, and distilled water. The specimen's color was measured each week by means of a spectrophotometer (CIE L*a*b* system). Statistical analysis was carried out performing an ANOVA and LSD Test in order to statistically analyze differences in L*a*b*and ∆E values. All materials showed significant discoloration (p < 0.05) when compared to the control group (immersed in distilled water). The Highest ∆E observed was with red wine, whereas coke led to the lowest one. Silorane showed the highest color stability compared with methacrylate-based composites. Methacrylate-based materials immersed in staining solutions showed lower color stability when compared with silorane. Great differences in ∆E were found among the methacrylate-based materials tested. Although color stability of methacrylate-based composites immersed in staining solutions has been widely investigated, this has not been done for long immersion periods with silorane-based composites.

  3. Process-Based Modeling of Constructed Wetlands

    Science.gov (United States)

    Baechler, S.; Brovelli, A.; Rossi, L.; Barry, D. A.

    2007-12-01

    Constructed wetlands (CWs) are widespread facilities for wastewater treatment. In subsurface flow wetlands, contaminated wastewater flows through a porous matrix, where oxidation and detoxification phenomena occur. Despite the large number of working CWs, system design and optimization are still mainly based upon empirical equations or simplified first-order kinetics. This results from an incomplete understanding of the system functioning, and may in turn hinder the performance and effectiveness of the treatment process. As a result, CWs are often considered not suitable to meet high water quality-standards, or to treat water contaminated with recalcitrant anthropogenic contaminants. To date, only a limited number of detailed numerical models have been developed and successfully applied to simulate constructed wetland behavior. Among these, one of the most complete and powerful is CW2D, which is based on Hydrus2D. The aim of this work is to develop a comprehensive simulator tailored to model the functioning of horizontal flow constructed wetlands and in turn provide a reliable design and optimization tool. The model is based upon PHWAT, a general reactive transport code for saturated flow. PHWAT couples MODFLOW, MT3DMS and PHREEQC-2 using an operator-splitting approach. The use of PHREEQC to simulate reactions allows great flexibility in simulating biogeochemical processes. The biogeochemical reaction network is similar to that of CW2D, and is based on the Activated Sludge Model (ASM). Kinetic oxidation of carbon sources and nutrient transformations (nitrogen and phosphorous primarily) are modeled via Monod-type kinetic equations. Oxygen dissolution is accounted for via a first-order mass-transfer equation. While the ASM model only includes a limited number of kinetic equations, the new simulator permits incorporation of an unlimited number of both kinetic and equilibrium reactions. Changes in pH, redox potential and surface reactions can be easily incorporated

  4. The Planning Process for Commanders: Leveraging Interagency Law Enforcement Capabilities for Stability Operations

    National Research Council Canada - National Science Library

    MacIsaac, Alexander J

    2006-01-01

    United States strategic guidance requires the Department of Defense (DoD) to work jointly with civilian departments to achieve national security objectives when conducting stability and reconstruction operations...

  5. Determination of the elastic modulus of fly ash-based stabilizer applied in the trackbed

    Science.gov (United States)

    Lojda, Vít; Lidmila, Martin; Pýcha, Marek

    2017-09-01

    This paper describes a unique application of a fly ash-based stabilizer in the trackbed of a railway main line. The key goals of the stabilizer application are to protect the subgrade against the ingress of rain water, to increase the frost resistance and to remediate the natural ground constituted of weathered rock. The stabilizer was designed as a mixture of fly ash, generated as a waste material from coal plants, gypsum, calcium oxide and water. The mixture recipe was developed in a laboratory over several years. In 2005, a trial section of a railway line with subgrade consisting of clay limestone (weathered marlite) was built in the municipality of Smiřice. Since then, periodical measurements including collection of samples for laboratory evaluation of the fly ash-based stabilizer have taken place. Over the time span of the measurements, changes in mineral composition and development of fly ash transforming structures leading to the formation of C-A-S-H gel were detected. This paper describes the experimental laboratory investigation of the influence of dynamic loading on the elastic modulus of fly ash stabilizer samples and the development of permanent deformation of the samples with increasing number of loading cycles.

  6. Influence of processing and intrinsic polymer parameters on photochemical stability of polythiophene thin films

    DEFF Research Database (Denmark)

    Vesterager Madsen, Morten; Tromholt, Thomas; Böttiger, Arvid P.L.

    2012-01-01

    -to-tail connected thiophene units. Annealing was found to relax the P3HT films and increase conjugation length and, in turn, increase stability observed as a delayed spectral blueshift caused by photochemical degradation. Crystallinity was found to play a minor role in terms of stability. Oxygen diffusion and light...... the technology closer to large-scale applications. © 2012 Elsevier Ltd. All rights reserved....

  7. C-terminal lysine repeats in Streptomyces topoisomerase I stabilize the enzyme–DNA complex and confer high enzyme processivity

    Science.gov (United States)

    Strzałka, Agnieszka; Szafran, Marcin J.; Strick, Terence

    2017-01-01

    Abstract Streptomyces topoisomerase I (TopA) exhibits exceptionally high processivity. The enzyme, as other actinobacterial topoisomerases I, differs from its bacterial homologs in its C-terminal domain (CTD). Here, bioinformatics analyses established that the presence of lysine repeats is a characteristic feature of actinobacterial TopA CTDs. Streptomyces TopA contains the longest stretch of lysine repeats, which terminate with acidic amino acids. DNA-binding studies revealed that the lysine repeats stabilized the TopA–DNA complex, while single-molecule experiments showed that their elimination impaired enzyme processivity. Streptomyces coelicolor TopA processivity could not be restored by fusion of its N-terminal domain (NTD) with the Escherichia coli TopA CTD. The hybrid protein could not re-establish the distribution of multiple chromosomal copies in Streptomyces hyphae impaired by TopA depletion. We expected that the highest TopA processivity would be required during the growth of multigenomic sporogenic hyphae, and indeed, the elimination of lysine repeats from TopA disturbed sporulation. We speculate that the interaction of the lysine repeats with DNA allows the stabilization of the enzyme–DNA complex, which is additionally enhanced by acidic C-terminal amino acids. The complex stabilization, which may be particularly important for GC-rich chromosomes, enables high enzyme processivity. The high processivity of TopA allows rapid topological changes in multiple chromosomal copies during Streptomyces sporulation. PMID:28981718

  8. Morpheme-Based Rendaku as a Rhythmic Stabilizer in Eastern Old Japanese Poetry

    Directory of Open Access Journals (Sweden)

    John KUPCHIK

    2012-05-01

    Full Text Available This paper explores the functions of morpheme-based rendaku, or “sequential voicing”, in Eastern Old Japanese poetry, with a focus on its function of maintaining rhythmic stability in poetic verse. It is argued that this function is implemented to avoid a hypermetrical line when no adjacent vowels exist as candidates for synchronic elision. Furthermore, a comparison with synchronic vowel elision is conducted. Based on the results, it is argued that morpheme-based rendaku is preferred to synchronic vowel elision when both are available options for maintaining the rhythmic stability of a line. Linguistic constraints blocking morpheme-based rendaku are also discussed to explain hypermetrical examples with potential, yet unrealized, morpheme-based rendaku.

  9. Large-Signal Lyapunov-Based Stability Analysis of DC/AC Inverters and Inverter-Based Microgrids

    Science.gov (United States)

    Kabalan, Mahmoud

    Microgrid stability studies have been largely based on small-signal linearization techniques. However, the validity and magnitude of the linearization domain is limited to small perturbations. Thus, there is a need to examine microgrids with large-signal nonlinear techniques to fully understand and examine their stability. Large-signal stability analysis can be accomplished by Lyapunov-based mathematical methods. These Lyapunov methods estimate the domain of asymptotic stability of the studied system. A survey of Lyapunov-based large-signal stability studies showed that few large-signal studies have been completed on either individual systems (dc/ac inverters, dc/dc rectifiers, etc.) or microgrids. The research presented in this thesis addresses the large-signal stability of droop-controlled dc/ac inverters and inverter-based microgrids. Dc/ac power electronic inverters allow microgrids to be technically feasible. Thus, as a prelude to examining the stability of microgrids, the research presented in Chapter 3 analyzes the stability of inverters. First, the 13 th order large-signal nonlinear model of a droop-controlled dc/ac inverter connected to an infinite bus is presented. The singular perturbation method is used to decompose the nonlinear model into 11th, 9th, 7th, 5th, 3rd and 1st order models. Each model ignores certain control or structural components of the full order model. The aim of the study is to understand the accuracy and validity of the reduced order models in replicating the performance of the full order nonlinear model. The performance of each model is studied in three different areas: time domain simulations, Lyapunov's indirect method and domain of attraction estimation. The work aims to present the best model to use in each of the three domains of study. Results show that certain reduced order models are capable of accurately reproducing the performance of the full order model while others can be used to gain insights into those three areas of

  10. Predictor-based stabilization for chained form systems with input time delay

    Directory of Open Access Journals (Sweden)

    Mnif Faïçal

    2016-12-01

    Full Text Available This note addresses the stabilization problem of nonlinear chained-form systems with input time delay. We first employ the so-called σ-process transformation that renders the feedback system under a linear form. We introduce a particular transformation to convert the original system into a delay-free system. Finally, we apply a state feedback control, which guarantees a quasi-exponential stabilization to all the system states, which in turn converge exponentially to zero. Then we employ the so-called -type control to achieve a quasi-exponential stabilization of the subsequent system. A simulation example illustrated on the model of a wheeled mobile robot is provided to demonstrate the effectiveness of the proposed approach.

  11. Raspberry Extract as Both a Stabilizer and a Reducing Agent in Environmentally Friendly Process of Receiving Colloidal Silver

    Directory of Open Access Journals (Sweden)

    Jolanta Pulit

    2013-01-01

    Full Text Available An ecofriendly method of nanosilver obtaining has been studied. The process involves the chemical reduction method carried out in aqueous environment. Silver nitrate (V was applied as a silver ions source. Raspberry extract was used as a natural source of both reducing and stabilizing agents. The total amount of phenolic compounds was determined by the Folin-Ciocalteu method. Obtained nanoparticles were analyzed by the dynamic light scattering technique so as to determine the particles size and suspension stability which was characterized by an electrokinetic potential. The results confirmed that the size of some nanoparticles was under 100 nm.

  12. Enabling structure-based drug design of Tyk2 through co-crystallization with a stabilizing aminoindazole inhibitor

    Science.gov (United States)

    2012-01-01

    Background Structure-based drug design (SBDD) can accelerate inhibitor lead design and optimization, and efficient methods including protein purification, characterization, crystallization, and high-resolution diffraction are all needed for rapid, iterative structure determination. Janus kinases are important targets that are amenable to structure-based drug design. Here we present the first mouse Tyk2 crystal structures, which are complexed to 3-aminoindazole compounds. Results A comprehensive construct design effort included N- and C-terminal variations, kinase-inactive mutations, and multiple species orthologs. High-throughput cloning and expression methods were coupled with an abbreviated purification protocol to optimize protein solubility and stability. In total, 50 Tyk2 constructs were generated. Many displayed poor expression, inadequate solubility, or incomplete affinity tag processing. One kinase-inactive murine Tyk2 construct, complexed with an ATP-competitive 3-aminoindazole inhibitor, provided crystals that diffracted to 2.5–2.6 Å resolution. This structure revealed initial “hot-spot” regions for SBDD, and provided a robust platform for ligand soaking experiments. Compared to previously reported human Tyk2 inhibitor crystal structures (Chrencik et al. (2010) J Mol Biol 400:413), our structures revealed a key difference in the glycine-rich loop conformation that is induced by the inhibitor. Ligand binding also conferred resistance to proteolytic degradation by thermolysin. As crystals could not be obtained with the unliganded enzyme, this enhanced stability is likely important for successful crystallization and inhibitor soaking methods. Conclusions Practical criteria for construct performance and prioritization, the optimization of purification protocols to enhance protein yields and stability, and use of high-throughput construct exploration enable structure determination methods early in the drug discovery process. Additionally, specific

  13. FIELD DEMONSTRATION OF LEAD-BASED PAINT REMOVAL AND INORGANIC STABILIZATION TECHNOLOGIES

    Science.gov (United States)

    A study was conducted to demonstrate the effectiveness of a wet abrasive blasting technology to remove lead-based paint from exterior wood siding and brock substrates and to stabilize the resultant blasting media (coal slag and mineral sand) paint debris to reduce the leachable l...

  14. Polyesteramides based on PET and nylon 2,T part 2. synthesis and thermal stability

    NARCIS (Netherlands)

    Bouma, K.; Groot, G.M.M.; Feijen, Jan; Gaymans, R.J.

    2000-01-01

    The synthesis and the thermal stability of polyesteramides based on PET and nylon 2,T (PETA) using DMT, T2T-dimethyl (N,N′-bis(p-carbo-methoxybenzoyl)ethanediamine) and 1,2-ethanediol as starting materials has been studied. The catalysts that were used are tetraisopropyl orthotitanate, manganese

  15. Stabilization techniques for reactive aggregate in soil-cement base course : technical summary.

    Science.gov (United States)

    2003-01-01

    The objectives of this research are 1) to identify the mineralogical properties of soil-cement bases which have heaved or can potentially heave, 2) to simulate expansion of cement-stabilized soil in the laboratory, 3) to correlate expansion with the ...

  16. A unifying energy-based approach to stability of power grids with market dynamics

    NARCIS (Netherlands)

    Stegink, Tjerk; De Persis, Claudio; van der Schaft, Arjan

    2017-01-01

    In this paper a unifying energy-based approach is provided to the modeling and stability analysis of power systems coupled with market dynamics. We consider a standard model of the power network with a third-order model for the synchronous generators involving voltage dynamics. By applying the

  17. VMCast: A VM-Assisted Stability Enhancing Solution for Tree-Based Overlay Multicast.

    Directory of Open Access Journals (Sweden)

    Weidong Gu

    Full Text Available Tree-based overlay multicast is an effective group communication method for media streaming applications. However, a group member's departure causes all of its descendants to be disconnected from the multicast tree for some time, which results in poor performance. The above problem is difficult to be addressed because overlay multicast tree is intrinsically instable. In this paper, we proposed a novel stability enhancing solution, VMCast, for tree-based overlay multicast. This solution uses two types of on-demand cloud virtual machines (VMs, i.e., multicast VMs (MVMs and compensation VMs (CVMs. MVMs are used to disseminate the multicast data, whereas CVMs are used to offer streaming compensation. The used VMs in the same cloud datacenter constitute a VM cluster. Each VM cluster is responsible for a service domain (VMSD, and each group member belongs to a specific VMSD. The data source delivers the multicast data to MVMs through a reliable path, and MVMs further disseminate the data to group members along domain overlay multicast trees. The above approach structurally improves the stability of the overlay multicast tree. We further utilized CVM-based streaming compensation to enhance the stability of the data distribution in the VMSDs. VMCast can be used as an extension to existing tree-based overlay multicast solutions, to provide better services for media streaming applications. We applied VMCast to two application instances (i.e., HMTP and HCcast. The results show that it can obviously enhance the stability of the data distribution.

  18. Modeling and Analysis of Harmonic Stability in an AC Power-Electronics-Based Power System

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Wu, Weimin

    2014-01-01

    This paper addresses the harmonic stability caused by the interactions among the wideband control of power converters and passive components in an AC power-electronicsbased power system. The impedance-based analytical approach is employed and expanded to a meshed and balanced threephase network...

  19. Evaluation of the effects of enzyme-based liquid chemical stabilizers on subgrade soils

    CSIR Research Space (South Africa)

    Mgangira, Martin B

    2009-07-01

    Full Text Available The purpose of this study was to asses the strength of enzyme treated soil material. Thus the aim of the paper is to present laboratory results on the effects of two enzyme-based liquid chemicals as soil stabilizers. Soil samples were prepared...

  20. The Grading Entropy-based Criteria for Structural Stability of Granular Materials and Filters

    Directory of Open Access Journals (Sweden)

    Janos Lőrincz

    2015-05-01

    Full Text Available This paper deals with three grading entropy-based rules that describe different soil structure stability phenomena: an internal stability rule, a filtering rule and a segregation rule. These rules are elaborated on the basis of a large amount of laboratory testing and from existing knowledge in the field. Use is made of the theory of grading entropy to derive parameters which incorporate all of the information of the grading curve into a pair of entropy-based parameters that allow soils with common behaviours to be grouped into domains on an entropy diagram. Applications of the derived entropy-based rules are presented by examining the reason of a dam failure, by testing against the existing filter rules from the literature, and by giving some examples for the design of non-segregating grading curves (discrete particle size distributions by dry weight. A physical basis for the internal stability rule is established, wherein the higher values of base entropy required for granular stability are shown to reflect the closeness between the mean and maximum grain diameters, which explains how there are sufficient coarser grains to achieve a stable grain skeleton.

  1. Morphological analysis of mouse lungs after treatment with magnetite-based magnetic fluid stabilized with DMSA

    International Nuclear Information System (INIS)

    Pereira Garcia, Monica; Miranda Parca, Renata; Braun Chaves, Sacha; Paulino Silva, Luciano; Djalma Santos, Antonio; Guerrero Marques Lacava, Zulmira; Cesar Morais, Paulo; Azevedo, Ricardo Bentes

    2005-01-01

    Mouse lungs injected with magnetic fluids based on magnetite nanoparticles stabilized by 2,3-dimercaptosuccinic acid were studied. We observed clusters of magnetic nanoparticles inside blood vessels, within the organ parenchyma and cells, as well as increased numbers of leukocytes in the organ. Both the particle concentration and organ inflammation diminished in a time-dependent manner

  2. High temperature stability of Cr-carbides in an experimental Co Re-based alloy

    Czech Academy of Sciences Publication Activity Database

    Mukherji, D.; Klauke, M.; Strunz, Pavel; Zizak, I.; Schumacher, G.; Wiedenmann, A.; Rösler, J.

    2010-01-01

    Roč. 101, č. 3 (2010), s. 340-348 ISSN 1862-5282 Institutional research plan: CEZ:AV0Z10480505 Keywords : Co-Re base alloy * Cr-carbide stability * Electron microscopy Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.860, year: 2010

  3. A Bargaining Set Based on External and Internal Stability and Endogenous Coalition Formation

    NARCIS (Netherlands)

    Lazarova, E.A.; Borm, P.E.M.; Montero, M.P.; Reijnierse, J.H.

    2006-01-01

    A new bargaining set based on notions of both internal and external stability is developed in the context of endogenous coalition formation.It allows to make an explicit distinction between within-group and outsidegroup deviation options.This type of distinction is not present in current bargaining

  4. VMCast: A VM-Assisted Stability Enhancing Solution for Tree-Based Overlay Multicast.

    Science.gov (United States)

    Gu, Weidong; Zhang, Xinchang; Gong, Bin; Zhang, Wei; Wang, Lu

    2015-01-01

    Tree-based overlay multicast is an effective group communication method for media streaming applications. However, a group member's departure causes all of its descendants to be disconnected from the multicast tree for some time, which results in poor performance. The above problem is difficult to be addressed because overlay multicast tree is intrinsically instable. In this paper, we proposed a novel stability enhancing solution, VMCast, for tree-based overlay multicast. This solution uses two types of on-demand cloud virtual machines (VMs), i.e., multicast VMs (MVMs) and compensation VMs (CVMs). MVMs are used to disseminate the multicast data, whereas CVMs are used to offer streaming compensation. The used VMs in the same cloud datacenter constitute a VM cluster. Each VM cluster is responsible for a service domain (VMSD), and each group member belongs to a specific VMSD. The data source delivers the multicast data to MVMs through a reliable path, and MVMs further disseminate the data to group members along domain overlay multicast trees. The above approach structurally improves the stability of the overlay multicast tree. We further utilized CVM-based streaming compensation to enhance the stability of the data distribution in the VMSDs. VMCast can be used as an extension to existing tree-based overlay multicast solutions, to provide better services for media streaming applications. We applied VMCast to two application instances (i.e., HMTP and HCcast). The results show that it can obviously enhance the stability of the data distribution.

  5. Intelligent Adaptation Process for Case Based Systems

    International Nuclear Information System (INIS)

    Nassar, A.M.; Mohamed, A.H.; Mohamed, A.H.

    2014-01-01

    Case Based Reasoning (CBR) Systems is one of the important decision making systems applied in many fields all over the world. The effectiveness of any CBR system based on the quality of the storage cases in the case library. Similar cases can be retrieved and adapted to produce the solution for the new problem. One of the main issues faced the CBR systems is the difficulties of achieving the useful cases. The proposed system introduces a new approach that uses the genetic algorithm (GA) technique to automate constructing the cases into the case library. Also, it can optimize the best one to be stored in the library for the future uses. However, the proposed system can avoid the problems of the uncertain and noisy cases. Besides, it can simply the retrieving and adaptation processes. So, it can improve the performance of the CBR system. The suggested system can be applied for many real-time problems. It has been applied for diagnosis the faults of the wireless network, diagnosis of the cancer diseases, diagnosis of the debugging of a software as cases of study. The proposed system has proved its performance in this field

  6. Developing a stability assessment method for power electronics-based microgrids

    Science.gov (United States)

    Austin, Peter M.

    Modern microgrids with microsources and energy storage are dependent on power electronics for control and regulation. Under certain circumstances power electronics can be destabilizing to the system due to an effect called negative incremental impedance. A careful review of the theory and literature on the subject is presented. This includes stability criteria for both AC and DC systems, as well as a discussion on the limitations posed by the analysis. A method to integrate stability assessment with higher-level microgrid architectural design is proposed. Crucial to this is impedance characterization of individual components, which was accomplished through simulation. DC and AC impedance measurement blocks were created in Matlab simulink to automate the process. A detailed switching-level model of a DC microgrid was implemented in simulink, including wind turbine microsource, battery storage, and three phase inverter. Maximum power point tracking (MPPT) was included to maximize the efficiency of the turbine and was implemented through three rectifier alternatives and control schemes. The stability characteristics of each was compared in the final analysis. Impedance data was collected individually from the components and used to assess stability in the system as a whole. The results included the assessment of stability, margin, and unstable operating points to demonstrate the feasibility of the proposed approach.

  7. Stability Comparison of Perovskite Solar Cells Based on Zinc Oxide and Titania on Polymer Substrates.

    Science.gov (United States)

    Dkhissi, Yasmina; Meyer, Steffen; Chen, Dehong; Weerasinghe, Hasitha C; Spiccia, Leone; Cheng, Yi-Bing; Caruso, Rachel A

    2016-04-07

    Device scale-up and long-term stability constitute two major hurdles that the emerging perovskite solar technology will have to overcome before commercialization. Here, a comparative study was performed between ZnO and TiO2 electron-selective layers, two materials that allow the low-temperature processing of perovskite solar cells on polymer substrates. Although the use of TiO2 is well established on glass substrates, ZnO was chosen because it can be readily printed at low temperature and offers the potential for the large-scale roll-to-roll manufacturing of flexible photovoltaics at a low cost. However, a rapid degradation of CH3 NH3 PbI3 was observed if it was deposited on ZnO, therefore, the influence of the perovskite film preparation conditions on its morphology and degradation kinetics was investigated. This study showed that CH3 NH3 PbI3 could withstand a higher temperature on TiO2 than ZnO and that TiO2-based perovskite devices were more stable than their ZnO analogues. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Synthesis of Nanosize Yttria-Stabilized Zirconia by a Molecular Decomposition Process

    Science.gov (United States)

    Jiang, Yi; Bhide, Sanjeevani V.; Virkar, Anil V.

    2001-02-01

    Nanosize yttria-stabilized zirconia (YSZ) was synthesized by a novel approach based on molecular decomposition. In this approach, yttria-doped BaZrO3 (Y-BaZrO3) or yttria-doped Na2ZrO3 (Y-Na2ZrO3) precursors were first synthesized from BaCO3, ZrO2, and Y2O3 or BaCO3 and commercial YSZ for Y-BaZrO3, and from Na2CO3 and YSZ for Y-Na2ZrO3, by a conventional solid-state reaction method. The precursors were then boiled to leach away the unwanted species, BaO or Na2O, either in a dilute HNO3 solution in water in the case of Y-BaZrO3, or in deionized water in the case of Y-Na2ZrO3. During boiling in HNO3 or water, the residue of Zr-Y-O skeleton formed fine, nanosize YSZ particles. The particle size of the as-synthesized nanosize powders estimated from X-ray diffraction peak broadening was ∼2-3 nm, while that estimated from specific surface area measurements by BET adsorption isotherm was ∼15 nm. Examination under a transmission electron microscope showed that the crystallite size was ∼5 nm. Samples were also examined by Raman spectroscopy to determine the crystallographic polymorph of the YSZ formed. Subsequent heating in air led to particle growth. However, even when the particles were heated to a temperature as high as 1000°C, the particle size was well in the nanosize range.

  9. Radiation stability of anion-exchange resins based on epichlorohydrin and vinylpyridines

    International Nuclear Information System (INIS)

    Zainutdinov, S.S.; Dzhalilov, A.T.; Askarov, M.A.

    1983-01-01

    The vigorous development of nuclear technology and atomic energy and the hydrometallurgy of the rare and radioactive metals has made it necessary to create and use ion-exchange materials possessing a high resistance to the action of ionizing radiations and the temperature. In view of this, the necessity has arisen for obtaining ion-exchange materials possessing adequate radiation stability. The results of an investigation of the radiation stability of anion-exchange resins based on the products of spontaneous polymerization in the interaction of epichlorohydrin with vinylpyridines show that they possess higher radiation resistance than the industrial anion-exchange resin AN-31 used at the present time

  10. Passivity-Based Stability Analysis and Damping Injection for Multiparalleled VSCs with LCL Filters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Loh, Poh Chiang

    2017-01-01

    is decomposed into a passive filter output admittance in series with an active admittance which is dependent on the current controller and the time delay. The frequency-domain passivity theory is then applied to the active admittance for system stability analysis. It reveals that the stability region...... of the single-loop grid current control is not only dependent on the time delay, but affected also by the resonance frequency of the converter-side filter inductor and filter capacitor. Further on, the damping injection based on the discrete derivative controller is proposed to enhance the passivity...

  11. Calculation and Simulation Study on Transient Stability of Power System Based on Matlab/Simulink

    Directory of Open Access Journals (Sweden)

    Shi Xiu Feng

    2016-01-01

    Full Text Available The stability of the power system is destroyed, will cause a large number of users power outage, even cause the collapse of the whole system, extremely serious consequences. Based on the analysis in single machine infinite system as an example, when at the f point two phase ground fault occurs, the fault lines on either side of the circuit breaker tripping resection at the same time,respectively by two kinds of calculation and simulation methods of system transient stability analysis, the conclusion are consistent. and the simulation analysis is superior to calculation analysis.

  12. Implementation of Power System Stabilizer Based on Conventional and Fuzzy Logic Controllers

    Directory of Open Access Journals (Sweden)

    Hanan Mikhael Habbi

    2018-03-01

    Full Text Available To damp the low-frequency oscillations which occurred due to the disturbances in the electrical power system, the generators are equipped with Power System Stabilizer (PSS that provide supplementary feedback stabilizing signals. The low-frequency oscillations in power system are classified as local mode oscillations, intra-area mode oscillation, and interarea mode oscillations. A suitable PSS model was selected considering the low frequencies oscillation in the inter-area mode based on conventional PSS and Fuzzy Logic Controller. Two types of (FIS Mamdani and suggeno were considered in this paper. The software of the methods was executed using MATLAB R2015a package.

  13. Outdoor altitude stabilization of QuadRotor based on type-2 fuzzy and fuzzy PID

    Science.gov (United States)

    Wicaksono, H.; Yusuf, Y. G.; Kristanto, C.; Haryanto, L.

    2017-11-01

    This paper presents a design of altitude stabilization of QuadRotor based on type-2 fuzzy and fuzzy PID. This practical design is implemented outdoor. Barometric and sonar sensor were used in this experiment as an input for the controller YoHe. The throttle signal as a control input was provided by the controller to leveling QuadRotor in particular altitude and known well as altitude stabilization. The parameter of type-2 fuzzy and fuzzy PID was tuned in several heights to get the best control parameter for any height. Type-2 fuzzy produced better result than fuzzy PID but had a slow response in the beginning.

  14. Pd-based alloy nanoclusters in ion-implanted silica: Formation and stability under thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Battaglin, G.; Cattaruzza, E.; De Marchi, G.; Gonella, F.; Mattei, G. E-mail: mattei@padova.infm.it; Maurizio, C.; Mazzoldi, P.; Parolin, M.; Sada, C.; Calliari, I

    2002-05-01

    In this work we report on the formation and stability under thermal annealing of Pd-Cu and Pd-Ag alloy nanoclusters obtained by sequential ion implantation in silica. The role of the annealing atmosphere on the alloy cluster formation and stability is investigated. A comparison is made with similar alloy-based systems obtained by sequential ion implantation in silica of Au-Ag or Au-Cu followed by annealing under similar conditions, in order to evidence the peculiar effect of the various metals in controlling the alloy evolution and/or decomposition.

  15. Global Asymptotic Stability for Delayed Neural Networks Using an Integral Inequality Based on Nonorthogonal Polynomials.

    Science.gov (United States)

    Zhang, Xian-Ming; Lin, Wen-Juan; Han, Qing-Long; He, Yong; Wu, Min

    2017-10-03

    This brief is concerned with global asymptotic stability of a neural network with a time-varying delay. First, by introducing an auxiliary vector with some nonorthogonal polynomials, a slack-matrix-based integral inequality is established, which includes some existing one as its special case. Second, a novel Lyapunov-Krasovskii functional is constructed to suit for the use of the obtained integral inequality. As a result, a less conservative stability criterion is derived, whose effectiveness is finally demonstrated through two well-used numerical examples.

  16. Effect of five staining solutions on the colour stability of two acrylics and three composite resins based provisional restorations.

    Science.gov (United States)

    Türker, Sebnem Begüm; Koçak, Ayşe; Aktepe, Esra

    2006-09-01

    The effect of coffee, tea, coca-cola, orange-juice and red wine on the colour stability of acrylic and composite based provisional materials were evaluated. Two acrylic resins and three composite resins were studied. 48 standardized specimens for each provisional material were prepared. Each group was divided into 6 subgroups. Specimens from each group were immersed in staining solutions at room temperature for 30 days. Red wine and tea caused the most significant colour changes and orange juice showed the least significant colour changes. deltaE of all of the provisional restorations materials was changed after the immersion in all of the staining solutions during the experimental process.

  17. Oxidative stability of mayonnaise and milk drink produced with structured lipids based on fish oil and caprylic acid

    DEFF Research Database (Denmark)

    Timm Heinrich, Maike; Xu, Xuebing; Nielsen, Nina Skall

    2004-01-01

    The oxidative stabilities of traditional fish oil (FO), randomized lipids (RFO), or specific structured lipids (SFO) produced from fish oil were compared when incorporated into either milk drink or mayonnaise. Furthermore, the effect of adding the potential antioxidants EDTA (240 mg...... not be ascribed to a single factor, but was most likely influenced by the structure of the lipids and differences in the processes used to produce and purify the lipids. In milk drinks based on SFO, EDTA slightly reduced oxidation, while lactoferrin did not exert a distinct antioxidative effect...

  18. L2 -stability of haptic systems with projection-based force reflection.

    Science.gov (United States)

    Polushin, Ilia G; Hasan, Mir Zayed

    2014-01-01

    The problem of stability of haptic interaction with virtual objects is addressed, where the force reflection is implemented using the projection-based principle. A stability condition is derived that generalizes some previously known results to the case of projection-based force reflection. It demonstrates that, in this case, an additional design parameter is brought in that allows to increase the admissible stiffness of the virtual wall and decrease the update rate without changing the damping of the haptic device. A passivity based interpretation of the result is given in terms of interconnection of generalized passive systems where the excess of passivity of haptic device compensates the shortage of passivity of the virtual wall. In particular, it is shown that the projection-based force reflection allows to arbitrarily increase the excess of passivity of the haptic device without changing its physical damping.

  19. Eigenvalue-based harmonic stability analysis method in inverter-fed power systems

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede

    2015-01-01

    This paper presents an eigenvalue-based harmonic stability analysis method for inverter-fed power systems. A full-order small-signal model for a droop-controlled Distributed Generation (DG) inverter is built first, including the time delay of digital control system, inner current and voltage...... control loops, and outer droop-based power control loop. Based on the inverter model, an overall small-signal model of a two-inverter-fed system is then established, and the eigenvalue-based stability analysis is subsequently performed to assess the influence of controller parameters on the harmonic...... resonance and instability in the power system. Eigenvalues associated with time delay of inverter and inner controller parameters is obtained, which shows the time delay has an important effect on harmonic instability of inverter-fed power systems. Simulation results are given for validating the proposed...

  20. Design of SBS-Modified Bitumen Stabilizer Powder Based on the Vulcanization Mechanism

    Directory of Open Access Journals (Sweden)

    Wengang Zhang

    2018-03-01

    Full Text Available In order to improve the problem of the bad thermal storage stability of Styrene-Butadiene-Styrene Block Copolymer Modified Bitumen (SBS-modified bitumen, the vulcanization reaction was selected as the basic mechanism for the research and development of the stabilizer. Sulfur, tetramethylthiuram disulfide (TMTD, zinc oxide, butylated hydroxytoluene (BHT, kaolin (Al2O3·2SiO2·2H2O and carbon-white (SiO2 were used as raw materials, and 32 kinds of components with different contents of raw materials were designed. The 48-h segregation softening point and other modified bitumen technical indicators, such as ductility, penetration, penetration index, viscosity, and so on, were tested and analyzed. The fluorescence microscope test was also conducted to explore the crosslinking situation based on the vulcanization reaction. The results show that the component with good performance of the SBS-modified bitumen stabilizer powder was S:TMTD:ZnO:BHT: Al2O3·2SiO2·2H2O = 60:16:4:20:1250 or S:TMTD:ZnO:BHT:SiO2 = 60:16:4:20:625. The optimum content of stabilizer powder was 0.9% (S/modified bitumen. The stabilizer was dry powder and can be directly put into bitumen. It can cross-link SBS and especially has an effect on preventing SBS segregation. The technical performance of SBS-modified bitumen with stabilizer powder, such as hot temperature performance, low temperature performance, anti-aging performance and thermal storage stability, all meet the relevant specifications.

  1. Robust stabilization control based on guardian maps theory for a longitudinal model of hypersonic vehicle.

    Science.gov (United States)

    Liu, Yanbin; Liu, Mengying; Sun, Peihua

    2014-01-01

    A typical model of hypersonic vehicle has the complicated dynamics such as the unstable states, the nonminimum phases, and the strong coupling input-output relations. As a result, designing a robust stabilization controller is essential to implement the anticipated tasks. This paper presents a robust stabilization controller based on the guardian maps theory for hypersonic vehicle. First, the guardian maps theories are provided to explain the constraint relations between the open subsets of complex plane and the eigenvalues of the state matrix of closed-loop control system. Then, a general control structure in relation to the guardian maps theories is proposed to achieve the respected design demands. Furthermore, the robust stabilization control law depending on the given general control structure is designed for the longitudinal model of hypersonic vehicle. Finally, a simulation example is provided to verify the effectiveness of the proposed methods.

  2. Fuzzy - Based Method of Detecting the Enviroment Character for UAV Optical Stabilization

    Directory of Open Access Journals (Sweden)

    David Novak

    2015-01-01

    Full Text Available An optical stabilization of UAV (UAS is a very important part of a structure in their control systems. Not only as a backup stabilization system in a case of IMU failure, but also as a main system, used for stabilization or navigation. In this paper the concept of a system for environment character detection is presented. The system can classify a surrounding environment depending on chosen characteristics. Such system can be used for a better horizon detection due to switching to a correct horizon detection algorithm, which can be used for determining the position of UAV. The system is based on Takagi - Sugeno fuzzy inference system and fuzzy artificial neural networks. An earlier work on this subject was presented last year, but concept of the system was redesigned with a usage of fuzzy artificial neural network for a more precisive outputs and automatic determination of characteristics of fuzzy sets on input.

  3. Testing and improving the redox stability of Ni-based solid oxide fuel cells

    DEFF Research Database (Denmark)

    Pihlatie, Mikko; Ramos, Tania; Kaiser, Andreas

    2009-01-01

    cells. When the symmetric cells are reduced and redox cycled isothermally at 850 °C, no major change in the serial or polarisation resistance of the cell and electrodes was measured. When the cells are, after the similar initial reduction treatment, redox cycled at 650 °C, the serial resistance remains......Despite active development, solid oxide fuel cells (SOFCs) based on Ni-YSZ anodes still suffer from thermomechanical instability under conditions where the anode side is exposed to oxidising conditions at high temperature. In the first part of the paper, structures and solutions, which could...... improve the redox stability of Ni-YSZ anode supported SOFC's in terms of dimensional and mechanical stability are reported. Porosity is identified as a major microstructural parameter linked to the dimensional and structural stability during redox cycling. The cumulative redox strain (CRS) after three...

  4. An Novel Continuation Power Flow Method Based on Line Voltage Stability Index

    Science.gov (United States)

    Zhou, Jianfang; He, Yuqing; He, Hongbin; Jiang, Zhuohan

    2018-01-01

    An novel continuation power flow method based on line voltage stability index is proposed in this paper. Line voltage stability index is used to determine the selection of parameterized lines, and constantly updated with the change of load parameterized lines. The calculation stages of the continuation power flow decided by the angle changes of the prediction of development trend equation direction vector are proposed in this paper. And, an adaptive step length control strategy is used to calculate the next prediction direction and value according to different calculation stages. The proposed method is applied clear physical concept, and the high computing speed, also considering the local characteristics of voltage instability which can reflect the weak nodes and weak area in a power system. Due to more fully to calculate the PV curves, the proposed method has certain advantages on analysing the voltage stability margin to large-scale power grid.

  5. Stabilization of Networked Distributed Systems with Partial and Event-Based Couplings

    Directory of Open Access Journals (Sweden)

    Sufang Zhang

    2015-01-01

    Full Text Available The stabilization problem of networked distributed systems with partial and event-based couplings is investigated. The channels, which are used to transmit different levels of information of agents, are considered. The channel matrix is introduced to indicate the work state of the channels. An event condition is designed for each channel to govern the sampling instants of the channel. Since the event conditions are separately given for different channels, the sampling instants of channels are mutually independent. To stabilize the system, the state feedback controllers are implemented in the system. The control signals also suffer from the two communication constraints. The sufficient conditions in terms of linear matrix equalities are proposed to ensure the stabilization of the controlled system. Finally, a numerical example is given to demonstrate the advantage of our results.

  6. Design of Power System Stabilizer based on Sliding Mode Control Theory for Multi- Machine Power System

    Directory of Open Access Journals (Sweden)

    Ghazanfar Shahgholian

    2010-01-01

    Full Text Available This paper presents a new method for designing of power system stabilizer (PSS based on sliding mode control (SMC technique. The control objective is to enhance stability and improve the dynamic response of the multi-machine power system. The mathematical model of the synchronous generator is first transformed into a form that facilitates the design of nonlinear control schemes. Then, a sliding mode controller is proposed. In order to test effectiveness of the proposed scheme, simulation will be carried out to analyze the small signal stability characteristics of the system about the steady state operating condition following the change in the parameters of the system and to the disturbances. For comparison, simulation of a conventional control PSS (lead-lag compensation type will be carried out. The main approach is to focus on the control performance which later is proven to have the degree of shorter reaching time and lower spike.

  7. On the Stability of the Finite Difference based Lattice Boltzmann Method

    KAUST Repository

    El-Amin, Mohamed

    2013-06-01

    This paper is devoted to determining the stability conditions for the finite difference based lattice Boltzmann method (FDLBM). In the current scheme, the 9-bit two-dimensional (D2Q9) model is used and the collision term of the Bhatnagar- Gross-Krook (BGK) is treated implicitly. The implicitness of the numerical scheme is removed by introducing a new distribution function different from that being used. Therefore, a new explicit finite-difference lattice Boltzmann method is obtained. Stability analysis of the resulted explicit scheme is done using Fourier expansion. Then, stability conditions in terms of time and spatial steps, relaxation time and explicitly-implicitly parameter are determined by calculating the eigenvalues of the given difference system. The determined conditions give the ranges of the parameters that have stable solutions.

  8. Correlation between Thermal Stability Map and Base Substitution Map of DNA from Related Bacteriophages

    Science.gov (United States)

    Husimi, Yuzuru; Shibata, Keizo

    1984-10-01

    The number density of substituted bases among related bacteriophages (fd, 1 and M13) is heterogeneous along the DNA strand although most base substitutions do not alter the coded amino acids. Local thermal stability of the double helical DNA is also heterogeneous. There is a negative correlation between these two maps. The same conclusion holds between less closely related phages, φX174 and G4.

  9. Phase Stability in Cobalt-Based L12 Quaternary Intermetallics From Density Functional Theory

    Science.gov (United States)

    Earwood, William P.

    The effects of higher order alloying additions (Mo, Ti, Ta, Hf, Fe, V) on the phase stability of L12 (gamma') intermetallics have been studied via first-principles. A 32 atom special-quasi-random structure was used to mimic the experimentally observed solid solution sublattice. Density of states distributions were generated in order to directly observe the impact of alloying additions on the position of the pseudogap and number of states at the Fermi level. Charge density differences across the supercell were visualized to analyze changes in bonding behavior. The results indicate that substitutions of Ti, Ta, and Hf in place of the central W atom increase phase stability by lowering the number of states at the Fermi level and decreasing the energy of the pseudogap relative to the unperturbed structure. Additionally, these substitutions increase the directional nature of the bond with nearest neighbor Co atoms. In particular, Co-Al bonds are reinforced at the expense of adjacent Co-W bonds which is expected to prolong dissociation of Co-Al bonds. Substitution of Fe led to a pronounced decrease in phase stability and directional bonding, indicating its inability to stabilize the base configuration or increase the bonding strength. V and Mo substitutions maintained the parent electron distribution to a greater degree than Ti, Ta, Hf, or Fe. However, V was shown to decrease the energy of the pseudogap by a significant amount and resembled the proposed ?' stabilizers more so than Mo.

  10. Application of electrochemical peroxidation (ECP) process for waste-activated sludge stabilization and system optimization using response surface methodology (RSM).

    Science.gov (United States)

    Gholikandi, Gagik Badalians; Kazemirad, Khashayar

    2018-03-01

    In this study, the performance of the electrochemical peroxidation (ECP) process for removing the volatile suspended solids (VSS) content of waste-activated sludge was evaluated. The Fe 2+ ions required by the process were obtained directly from iron electrodes in the system. The performance of the ECP process was investigated in various operational conditions employing a laboratory-scale pilot setup and optimized by response surface methodology (RSM). According to the results, the ECP process showed its best performance when the pH value, current density, H 2 O 2 concentration and the retention time were 3, 3.2 mA/cm 2 , 1,535 mg/L and 240 min, respectively. In these conditions, the introduced Fe 2+ concentration was approximately 500 (mg/L) and the VSS removal efficiency about 74%. Moreover, the results of the microbial characteristics of the raw and the stabilized sludge demonstrated that the ECP process is able to remove close to 99.9% of the coliforms in the raw sludge during the stabilization process. The energy consumption evaluation showed that the required energy of the ECP reactor (about 1.8-2.5 kWh (kg VSS removed) -1 ) is considerably lower than for aerobic digestion, the conventional waste-activated sludge stabilization method (about 2-3 kWh (kg VSS removed) -1 ). The RSM optimization process showed that the best operational conditions of the ECP process comply with the experimental results, and the actual and the predicted results are in good conformity with each other. This feature makes it possible to predict the introduced Fe 2+ concentrations into the system and the VSS removal efficiency of the process precisely.

  11. Oxygen permeation and thermo-chemical stability of oxygen separation membrane materials for the oxyfuel process

    Energy Technology Data Exchange (ETDEWEB)

    Ellett, Anna Judith

    2009-07-01

    analysis (TGA) and thermo mechanical analysis (TMA). An increase in thermal expansion and oxygen permeation associated with an increase in oxygen vacancy concentration, observed also in the TGA curves, occurs during heating. BSCF50 exhibits permeation fluxes well above those of LSCF58, PSCF58 and La{sub 2}NiO{sub 4+{delta}}, which are quite similar to each other. After exposure, no degradation of LSCF58, La{sub 2}NiO{sub 4+{delta}} and PSCF58 occurs. On the other hand BSCF50 is found to be unstable in CO{sub 2}- and/or H{sub 2}O-containing atmospheres and also to exhibit a chemical demixing. The thermo-chemical stability and the oxygen permeation performances are both crucial factors in the selection of high purity oxygen separation membranes for the oxyfuel process, thus making LSCF58, PSCF58 and La{sub 2}NiO{sub 4+{delta}} in this study the most suitable materials for this application. Serious issues arise, however, from the fact that secondary non-ion conducting oxide phases are formed in the bulk of every material, forming obstacles for oxygen ion migration, and also that a reaction with chromia occurs, preventing their use without protection. (orig.)

  12. Parallel processing using an optical delay-based reservoir computer

    Science.gov (United States)

    Van der Sande, Guy; Nguimdo, Romain Modeste; Verschaffelt, Guy

    2016-04-01

    Delay systems subject to delayed optical feedback have recently shown great potential in solving computationally hard tasks. By implementing a neuro-inspired computational scheme relying on the transient response to optical data injection, high processing speeds have been demonstrated. However, reservoir computing systems based on delay dynamics discussed in the literature are designed by coupling many different stand-alone components which lead to bulky, lack of long-term stability, non-monolithic systems. Here we numerically investigate the possibility of implementing reservoir computing schemes based on semiconductor ring lasers. Semiconductor ring lasers are semiconductor lasers where the laser cavity consists of a ring-shaped waveguide. SRLs are highly integrable and scalable, making them ideal candidates for key components in photonic integrated circuits. SRLs can generate light in two counterpropagating directions between which bistability has been demonstrated. We demonstrate that two independent machine learning tasks , even with different nature of inputs with different input data signals can be simultaneously computed using a single photonic nonlinear node relying on the parallelism offered by photonics. We illustrate the performance on simultaneous chaotic time series prediction and a classification of the Nonlinear Channel Equalization. We take advantage of different directional modes to process individual tasks. Each directional mode processes one individual task to mitigate possible crosstalk between the tasks. Our results indicate that prediction/classification with errors comparable to the state-of-the-art performance can be obtained even with noise despite the two tasks being computed simultaneously. We also find that a good performance is obtained for both tasks for a broad range of the parameters. The results are discussed in detail in [Nguimdo et al., IEEE Trans. Neural Netw. Learn. Syst. 26, pp. 3301-3307, 2015

  13. Desert Pavement Process and Form: Modes and Scales of Landscape Stability and Instability in Arid Regions

    Science.gov (United States)

    Wells, Stephen G.; McFadden, Leslie D.; McDonald, Eric V.; Eppes, Martha C.; Young, Michael H.; Wood, Yvonne A.

    2014-05-01

    Desert pavements are recognized in arid landscapes around the world, developing via diminution of constructional/depositional landform relief and creating a 1-2 stone thick armor over a "stone free" layer. Surface exposure dating demonstrates that clasts forming the desert pavements are maintained at the land surface over hundreds of thousands of years, as aeolian fines are deposited on the land surface, transported into the underlying parent material and incorporated into accretionary soil horizons (e.g., the stone free or vesicular [Av] horizon). This surface armor provides long-term stability over extensive regions of the landscape. Over shorter time periods and at the landform-element scale, dynamic surficial processes (i.e., weathering, runoff) continue to modify the pavement form. Clast size reduction in comparison to underlying parent material, along with armoring and packing of clasts in pavements contribute to their persistence, and studies of crack orientations in pavement clasts indicate physical weathering and diminution of particle size are driven by diurnal solar insolation. Over geologic time, cracks form and propagate from tensile stresses related to temporal and spatial gradients in temperature that evolve and rotate in alignment with the sun's rays. Observed multimodal nature of crack orientations appear related to seasonally varying, latitude-dependent temperature fields resulting from solar angle and weather conditions. Surface properties and their underlying soil profiles vary across pavement surfaces, forming a landscape mosaic and controlling surface hydrology, ecosystem function and the ultimate life-cycle of arid landscapes. In areas of well-developed pavements, surface infiltration and soluble salt concentrations indicate that saturated hydraulic conductivity of Av horizons decline on progressively older alluvial fan surfaces. Field observations and measurements from well-developed desert pavement surfaces landforms also yield

  14. Study of the F sup(+)sub(2) centers stabilization process in LiF:OH sup(-) crystals and spectroscopy of the OH sup(-) dissociation

    International Nuclear Information System (INIS)

    Courrol, L.C.

    1990-01-01

    We studied the process of stabilization of the F sup(+) sub(2) centers in irradiated LiF:OH sup(-) single crystals. A consistent investigation of the wide number of defects produced by the radiation damage in the lattice allowed us to improve the experimental conditions to increase the final number of stabilized F sup(+) sub(2). It has been established the model for the F sup(+) sub(2):O sup(2-) formation in LiF:OH sup(-) irradiated based on a statistical distribution of the defects produced during the electron irradiation at 230K. These stabilized centers are formed during the thermal diffusion of the anionic vacancies in competition with the isolated F sup(+) sub(2) centers. A critical distance of thirteen lattice parameters determined for a vacancy suggested that the O sup(2-) -α dipole is the precursor entity for the F sup(+) sub(2):O sup(2-) creation. A further increasing of the F sup(+) sub(2) stabilized concentration was obtained after the e sup(-) - irradiation and the vacancy generation process by irradiating the samples at 77K with a small dose of gamma rays. The same net effect was seen after the e sup(-) - irradiation by keeping the samples at room temperature for at least 6 months as a consequence of the thermal activated diffusion of the remaining O sup(2-) -α dipoles and reaction with F centers. The sub-products of the OH sup(-) dissociation induced by the high energy irradiation were identified by spectroscopical analysis. A new defect was identified as a F sub(z) center containing a water molecule. Its luminescence properties and stability has been determined. Future investigations and some implications from the model has been discussed. (author)

  15. Influence of denture cleansers on the color stability of three types of denture base acrylic resin.

    Science.gov (United States)

    Hong, Guang; Murata, Hiroshi; Li, YingAi; Sadamori, Sinshuke; Hamada, Taizo

    2009-03-01

    Color stability is an important property of denture base acrylic resin. Color changes indicate aging or damaged dental materials. However, little information is available on the influence of denture cleansers on the color stability of acrylic resins. The purpose of this study was to determine the influence of denture cleansers on the color stability of 3 different types of acrylic resin. One heat-polymerized (HP) acrylic denture base resin (Acron), 1 autopolymerized (AP) hard direct reline acrylic resin (Denture Liner), and 1 visible-light-polymerized (VLP) hard direct reline acrylic resin (Tokuso Lite-Rebase) were evaluated. Five specimens of each material, 10 x 10 x 2 mm, were immersed in 1 of 9 commercial denture cleanser solutions or distilled water (control). Color changes were measured with a colorimeter and evaluated using the CIE L*a*b* colorimetric system. Data were analyzed using 1-way and 3-way ANOVA and the Student-Newman-Keuls test (alpha=.05). Significant differences (P<.05) were found among the acrylic resins and denture cleansers in terms of color change (DeltaE) produced after 365 days. The DeltaE values of all denture base acrylic resins increased with time. The DeltaE of the AP acrylic resin was larger than that of the other acrylic resins. The least discoloration was found with ZTC denture cleanser (acid type). The influence of alkaline peroxide-type denture cleanser (Steradent) on the color stability of HP acrylic resin and AP acrylic resin was significantly greater (P<.05) than that of the other cleansers. These results suggest that the color stability of denture base acrylic resins is influenced by polymerization type and the type of denture cleanser used.

  16. Processed beetroot (Beta vulgaris L. as a natural antioxidant in mayonnaise: Effects on physical stability, texture and sensory attributes

    Directory of Open Access Journals (Sweden)

    Vassilios Raikos

    2016-12-01

    Full Text Available The oxidative and physical stability of the reformulated mayonnaise with processed beetroot was investigated and compared with a control (mayonnaise without beetroot and a commercially available product. Processing of beetroot had an impact on the structural integrity of the antioxidants present. Microwaving (960 W for 7 min was advantageous for preserving the betalain and polyphenol content of beetroot compared to roasting (180 °C for 90 min and boiling (100 °C for 30 min. The oxidative stability of mayonnaise samples was determined by Rancimat and the thiobarbituric (TBA assay. The addition of microwaved beetroot significantly enhanced the oxidative stability of mayonnaise at the end of a storage period of 4 weeks (4 °C. Although no significant differences (P > 0.05 were detected between the mayonnaise samples containing beetroot and the commercial control, the latter was less susceptible to oxidation during storage. The turbiscan stability index (TSI revealed that the commercial mayonnaise was less prone to destabilization phenomena. All the textural parameters increased with the incorporation of beetroot. The sensory evaluation revealed that, with the exception of graininess and uniformity, most of the sensory attributes are preserved if not improved with the addition of beetroot.

  17. Stability and efficiency of dye-sensitized solar cells based on papaya-leaf dye

    Science.gov (United States)

    Suyitno, Suyitno; Saputra, Trisma Jaya; Supriyanto, Agus; Arifin, Zainal

    2015-09-01

    The present article reports on the enhancement of the performance and stability of natural dye-based dye-sensitized solar cells (DSSCs). Natural dyes extracted from papaya leaves (PL) were investigated as sensitizers in TiO2-based DSSCs and evaluated in comparison with N719 dye. The acidity of the papaya-leaf extract dyes was tuned by adding benzoic acid. The TiO2 film-coated fluorine-doped tin oxide glass substrates were prepared using the doctor-blade method, followed by sintering at 450 °C. The counter electrode was coated by chemically deposited catalytic platinum. The working electrodes were immersed in N719 dye and papaya dye solutions with concentrations of 8 g/100 mL. The absorbance spectra of the dyes were obtained by ultra-violet-visible spectroscopy. The energy levels of the dyes were measured by the method of cyclic voltammetry. In addition, Fourier transform infrared spectroscopy was used to determine the characteristic functionalities of the dye molecules. The DSSC based on the N719 dye displayed a highest efficiency of 0.87% whereas those based on papaya-leaf dye achieved 0.28% at pH 3.5. The observed improved efficiency of the latter was attributed to the increased current density value. Furthermore, the DSSCs based on papaya-leaf dye with pH 3.5-4 exhibited better stability than those based on N719 dye. However, further studies are required to improve the current density and stability of natural dye-based DSSCs, including the investigation of alternative dye extraction routes, such as isolating the pure chlorophyll from papaya leaves and stabilizing it.

  18. Stability and efficiency of dye-sensitized solar cells based on papaya-leaf dye.

    Science.gov (United States)

    Suyitno, Suyitno; Saputra, Trisma Jaya; Supriyanto, Agus; Arifin, Zainal

    2015-09-05

    The present article reports on the enhancement of the performance and stability of natural dye-based dye-sensitized solar cells (DSSCs). Natural dyes extracted from papaya leaves (PL) were investigated as sensitizers in TiO2-based DSSCs and evaluated in comparison with N719 dye. The acidity of the papaya-leaf extract dyes was tuned by adding benzoic acid. The TiO2 film-coated fluorine-doped tin oxide glass substrates were prepared using the doctor-blade method, followed by sintering at 450 °C. The counter electrode was coated by chemically deposited catalytic platinum. The working electrodes were immersed in N719 dye and papaya dye solutions with concentrations of 8 g/100 mL. The absorbance spectra of the dyes were obtained by ultra-violet-visible spectroscopy. The energy levels of the dyes were measured by the method of cyclic voltammetry. In addition, Fourier transform infrared spectroscopy was used to determine the characteristic functionalities of the dye molecules. The DSSC based on the N719 dye displayed a highest efficiency of 0.87% whereas those based on papaya-leaf dye achieved 0.28% at pH 3.5. The observed improved efficiency of the latter was attributed to the increased current density value. Furthermore, the DSSCs based on papaya-leaf dye with pH 3.5-4 exhibited better stability than those based on N719 dye. However, further studies are required to improve the current density and stability of natural dye-based DSSCs, including the investigation of alternative dye extraction routes, such as isolating the pure chlorophyll from papaya leaves and stabilizing it. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Oxidative stability of rice bran, corn, canola, sunflower and soybean oils d baking process and storage of bread

    Directory of Open Access Journals (Sweden)

    Najmeh Jahani

    2016-01-01

    Full Text Available Oxidation of bread lipids during baking and storage reduces the nutritional value of the product and leads to the formation of off-flavors and off-odors. In this research, oxidative stability of rice bran, corn, canola, sunflower and soybean oils during Brotchen bread baking process and storage was evaluated. Baking process caused a significant increase in oxidative indices such as peroxide, anisidine, Totox and thiobarbitoric acid values and free fatty acid content. However, storage of breads for 6 days in room temperature did not affect the value of the indices. Generaly, the value of the indices in bread containing rice bran oil was lower than those of the other breads, which indicated the higher oxidative stability of rice bran oil in baking process and storage. Pure oils treated in simulated baking process and storage had an oxidative quality similar to that of breads. This means that bread ingridients may not have an effect on oil oxidative stability. Bread containing rice bran oil gained also higher scores in sensory evaluation, which of course were in agree with its better oxidative status.

  20. Model-based software process improvement

    Science.gov (United States)

    Zettervall, Brenda T.

    1994-01-01

    The activities of a field test site for the Software Engineering Institute's software process definition project are discussed. Products tested included the improvement model itself, descriptive modeling techniques, the CMM level 2 framework document, and the use of process definition guidelines and templates. The software process improvement model represents a five stage cyclic approach for organizational process improvement. The cycles consist of the initiating, diagnosing, establishing, acting, and leveraging phases.

  1. Lévy based Cox point processes

    DEFF Research Database (Denmark)

    Hellmund, Gunnar; Prokesová, Michaela; Jensen, Eva Bjørn Vedel

    2008-01-01

    In this paper we introduce Lévy-driven Cox point processes (LCPs) as Cox point processes with driving intensity function Λ defined by a kernel smoothing of a Lévy basis (an independently scattered, infinitely divisible random measure). We also consider log Lévy-driven Cox point processes (LLCPs...

  2. Compliance in Resource-based Process Models

    NARCIS (Netherlands)

    Colombo Tosatto, S.; Elrakaiby, Y.; Ziafati, P.

    2013-01-01

    Execution of business processes often requires resources, the use of which is usually subject to constraints. In this paper, we study the compliance of business processes with resource usage policies. To this end, we relate the execution of a business process to its resource requirements in terms of

  3. Stability and synchronization of memristor-based fractional-order delayed neural networks.

    Science.gov (United States)

    Chen, Liping; Wu, Ranchao; Cao, Jinde; Liu, Jia-Bao

    2015-11-01

    Global asymptotic stability and synchronization of a class of fractional-order memristor-based delayed neural networks are investigated. For such problems in integer-order systems, Lyapunov-Krasovskii functional is usually constructed, whereas similar method has not been well developed for fractional-order nonlinear delayed systems. By employing a comparison theorem for a class of fractional-order linear systems with time delay, sufficient condition for global asymptotic stability of fractional memristor-based delayed neural networks is derived. Then, based on linear error feedback control, the synchronization criterion for such neural networks is also presented. Numerical simulations are given to demonstrate the effectiveness of the theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Real-time impedance-based stability assessment of grid converter interactions

    DEFF Research Database (Denmark)

    Messo, Tuomas; Luhtala, Roni; Roinila, Tomi

    2017-01-01

    This paper proposes a method to monitor the impedance-based stability margin of grid-connected converters in real-time. A three-phase converter is configured to inject a broadband perturbation on top of its nominal output current to enable online identification of grid impedance. The ratio...... of converter and grid impedance is computed in real-time by utilizing the measured grid impedance and the analytical impedance model of the inverter. A Nyquist contour is plotted based on the impedance ratio. The contour can be used to assess impedance-based stability margin and to allow, e.g., adaptive tuning......, more efficient post-fault diagnostics or to enable re-selection of control parameters. The method is implemented on a dSPACE real-time control platform and the associated Control Desk software. The paper also discusses potential limitations and suggests future improvements. A short video is available...

  5. Effect of base media on the stability of annatto dye in industrial products

    International Nuclear Information System (INIS)

    Audetuyi, A.O.; Lajide, L.; Popoola, A.V.

    2006-01-01

    Colour stability of the versatile annatto dye was examined to monitor the effects of base media on industrial products. The dye was incorporated in two media, namely, palm kernel oil used in products such as body cream and soap, and paraffin wax used in shoe polish and household candle wax. These products were exposed to various light conditions for a specific period before assessment. The melting point of the dye was determined as 176-178 degree C with a molar absorptivity of 13,600 mol/sub -1/ cm/sub -1/ at 545 nm. It imparted its brilliant yellow/orange colouration in industrial products as the colour stability depends on the compounding base media of the products. Losses of beta-carotene was higher and faster in nonaqueous environment as paraffin wax showed low fastness rating values, than in the palm kernel oil based aqueous medium products. (author)

  6. Trajectory Generation and Stability Analysis for Reconfigurable Klann Mechanism Based Walking Robot

    Directory of Open Access Journals (Sweden)

    Jaichandar Kulandaidaasan Sheba

    2016-06-01

    Full Text Available Reconfigurable legged robots based on one degree of freedom are highly desired because they are effective on rough and irregular terrains and they provide mobility in such terrain with simple control schemes. It is necessary that reconfigurable legged robots should maintain stability during rest and motion, with a minimum number of legs while maintaining their full range of walking patterns resulting from different gait configuration. In this paper we present a method to generate input trajectory for reconfigurable quadruped robots based on Klann mechanism to properly synchronize movement. Six useful gait cycles based on this reconfigurable Klann mechanism for quadruped robots has been clearly shown here. The platform stability for these six useful gait cycles are validated through simulated results which clearly shows the capabilities of reconfigurable design.

  7. Cu-based shape memory alloys with enhanced thermal stability and mechanical properties

    International Nuclear Information System (INIS)

    Chung, C.Y.; Lam, C.W.H.

    1999-01-01

    Cu-based shape memory alloys were developed in the 1960s. They show excellent thermoelastic martensitic transformation. However the problems in mechanical properties and thermal instability have inhibited them from becoming promising engineering alloys. A new Cu-Zn-Al-Mn-Zr Cu-based shape memory alloy has been developed. With the addition of Mn and Zr, the martensitic transformation behaviour and the grain size ca be better controlled. The new alloys demonstrates good mechanical properties with ultimate tensile strenght and ductility, being 460 MPa and 9%, respectively. Experimental results revealed that the alloy has better thermal stability, i.e. martensite stabilisation is less serious. In ordinary Cu-Zn-Al alloys, martensite stabilisation usually occurs at room temperature. The new alloy shows better thermal stability even at elevated temperature (∝150 C, >A f =80 C). A limited small amount of martensite stabilisation was observed upon ageing of the direct quenched samples as well as the step quenched samples. This implies that the thermal stability of the new alloy is less dependent on the quenching procedure. Furthermore, such minor martensite stabilisation can be removed by subsequent suitable parent phase ageing. The new alloy is ideal for engineering applications because of its better thermal stability and better mechanical properties. (orig.)

  8. Robust Stability Clearance of Flight Control Law Based on Global Sensitivity Analysis

    Directory of Open Access Journals (Sweden)

    Liuli Ou

    2014-01-01

    Full Text Available To validate the robust stability of the flight control system of hypersonic flight vehicle, which suffers from a large number of parametrical uncertainties, a new clearance framework based on structural singular value (μ theory and global uncertainty sensitivity analysis (SA is proposed. In this framework, SA serves as the preprocess of uncertain model to be analysed to help engineers to determine which uncertainties affect the stability of the closed loop system more slightly. By ignoring these unimportant uncertainties, the calculation of μ can be simplified. Instead of analysing the effect of uncertainties on μ which involves solving optimal problems repeatedly, a simpler stability analysis function which represents the effect of uncertainties on closed loop poles is proposed. Based on this stability analysis function, Sobol’s method, the most widely used global SA method, is extended and applied to the new clearance framework due to its suitability for system with strong nonlinearity and input factors varying in large interval, as well as input factors subjecting to random distributions. In this method, the sensitive indices can be estimated via Monte Carlo simulation conveniently. An example is given to illustrate the efficiency of the proposed method.

  9. Pedicle-Based Non-fusion Stabilization Devices: A Critical Review and Appraisal of Current Evidence.

    Science.gov (United States)

    Obernauer, Jochen; Kavakebi, Pujan; Quirbach, Sebastian; Thomé, Claudius

    2014-01-01

    Over the last decades, spinal fusion has become one of the most important principles in surgical treatment of spinal pathologies. Despite the undoubted benefits of fusion surgery, there are several drawbacks associated with this technique, including adjacent segment degeneration and pseudoarthrosis. Based on biomechanical data, dynamic stabilization of the spine is intended to ameliorate adjacent level degeneration by stabilizing vertebral motion in defined planes and mimicking natural spine movements.In this paper, we review the literature and discuss past and present pedicle-based non-fusion dynamic stabilization devices. Although there is a paucity of high-quality prospective trials, studies have indicated both promising and disappointing results. In comparison to 360° fusion surgery, the perioperative risk seems to be lower. Other complications like screw loosening, however, have been reported with various systems, while a reduction of adjacent segment disease has not yet been demonstrated. The necessary degree of restabilization to achieve pain-free motion seems to vary greatly between patients and current systems are far from perfection. If these problems can be solved, dynamic stabilization may nevertheless be an important option of spinal surgery in the future.

  10. Electromyographic response of global abdominal stabilizers in response to stable- and unstable-base isometric exercise.

    Science.gov (United States)

    Atkins, Stephen J; Bentley, Ian; Brooks, Darrell; Burrows, Mark P; Hurst, Howard T; Sinclair, Jonathan K

    2015-06-01

    Core stability training traditionally uses stable-base techniques. Less is known as to the use of unstable-base techniques, such as suspension training, to activate core musculature. This study sought to assess the neuromuscular activation of global core stabilizers when using suspension training techniques, compared with more traditional forms of isometric exercise. Eighteen elite level, male youth swimmers (age, 15.5 ± 2.3 years; stature, 163.3 ± 12.7 cm; body mass, 62.2 ± 11.9 kg) participated in this study. Surface electromyography (sEMG) was used to determine the rate of muscle contraction in postural musculature, associated with core stability and torso bracing (rectus abdominus [RA], external obliques [EO], erector spinae [ES]). A maximal voluntary contraction test was used to determine peak amplitude for all muscles. Static bracing of the core was achieved using a modified "plank" position, with and without a Swiss ball, and held for 30 seconds. A mechanically similar "plank" was then held using suspension straps. Analysis of sEMG revealed that suspension produced higher peak amplitude in the RA than using a prone or Swiss ball "plank" (p = 0.04). This difference was not replicated in either the EO or ES musculature. We conclude that suspension training noticeably improves engagement of anterior core musculature when compared with both lateral and posterior muscles. Further research is required to determine how best to activate both posterior and lateral musculature when using all forms of core stability training.

  11. Power system stability enhancement employing controllers based on a versatile modeling

    Science.gov (United States)

    Chung, Chi Yung

    Rapid advances in power electronics have made it both practicable and economic to design powerful thyristor-controlled devices, such as Flexible AC Transmission Systems (FACTS), for stability enhancements. The discrepancies of existing modeling approaches have limited the feasibility of handling these devices or designing its damping controller. In this thesis, a versatile and generalized approach to model standard power system components is proposed. The more systematic and realistic representation, accompanied by the development of powerful eigenvalue-analysis techniques, facilitates the study of small signal stability (monotonic and oscillatory) of the power systems. In monotonic stability study, the effect of exciter and governor is critically reviewed based on the exploitation of eigenvalues, modal and sensitivity analyses over a wide range of operating conditions. In oscillatory stability study, a common FACTS device, the static var compensator (SVC), is used to improve system damping. This study reveals the inadequacy of many conventional methodologies in SVC design since they have ignored (or cannot handle) some important factors such as SVC mode instability and robustness of the power system. Two approaches, combined sensitivities and Hinfinity algorithms, are introduced to solve these limitations. Finally, an extended Hinfinity algorithm, which is applied to PSS design and successfully solves certain limitations of the existing H infinity based PSS design, is also presented. Although these studies are developed on selected controller devices or typical systems for convenience of discussion, extension to more complex systems can be dealt with in a similar way because of the versatility of the proposed modeling methodology.

  12. Carbon Stabilization by Clays in the Environment: Process and Characterization Methods

    Science.gov (United States)

    Organic matter (OM) in soil plays vital roles with respect to global climate change, as the largest terrestrial reservoir of organic carbon, and with respect to soil quality through the stabilization of soil structure and the retention and cycling of plant nutrients. The interactions between clay mi...

  13. Recovery of Metals and Stabilization of Arsenic from (Bio-)Leaching Operations by Engineered Biological Processes

    NARCIS (Netherlands)

    Gonzalez Contreras, P.A.; weghuis, M.O.; Weijma, J.; Buisman, C.J.N.

    2013-01-01

    This paper focuses on the application of biotechnological stabilization of arsenic from (bio-) leaching operations. One of the latest applications of the Thioteq technology is arsenic immobilization. The Thioteq-scorodite biorecovery reactor is an aerobic system to immobilise arsenic in

  14. Stability investigations of zinc and cobalt precipitates immobilized by in situ bioprecipitation (ISBP) process

    KAUST Repository

    Satyawali, Yamini

    2010-09-01

    In situ bioprecipitation (ISBP), which involves immobilizing the metals as precipitates (mainly sulphides) in the solid phase, is an effective method of metal removal from contaminated groundwater. This study investigated the stability of metal precipitates formed after ISBP in two different solid-liquid matrices (artificial and natural). The artificial matrix consisted of sand, Zn (200mgL-1), artificial groundwater and a carbon source (electron donor). Here the stability of the Zn precipitates was evaluated by manipulation of redox and pH. The natural system matrices included aquifer material and groundwater samples collected from three different metal (Zn and Co) contaminated sites and different carbon sources were provided as electron donors. In the natural matrices, metal precipitates stability was assessed by changing aquifer redox conditions, sequential extraction, and BIOMET® assay. The results indicated that, in the artificial matrix, redox manipulation did not impact the Zn precipitates. However the sequential pH change proved detrimental, releasing 58% of the precipitated Zn back into liquid phase. In natural matrices, the applied carbon source largely affected the stability of metal precipitates. Elemental analysis performed on the precipitates formed in natural matrix showed that the main elements of the precipitates were sulphur with Zn and Co. © 2010 Elsevier B.V.

  15. Shelf life stability comparison in air for solution processed pristine PDPP3T polymer and doped spiro-OMeTAD as hole transport layer for perovskite solar cell

    Directory of Open Access Journals (Sweden)

    Ashish Dubey

    2016-06-01

    Full Text Available This data in brief includes forward and reverse scanned current density–voltage (J–V characteristics of perovskite solar cells with PDPP3T and spiro-OMeTAD as HTL, stability testing conditions of perovskite solar cell shelf life in air for both PDPP3T and spiro-OMeTAD as HTL as per the description in Ref. [1], and individual J–V performance parameters acquired with increasing time exposed in ambient air are shown for both type of devices using PDPP3T and spiro-OMeTAD as HTL. The data collected in this study compares the device stability with time for both PDPP3T and spiro-OMeTAD based perovskite solar cells and is directly related to our research article “solution processed pristine PDPP3T polymer as hole transport layer for efficient perovskite solar cells with slower degradation” [2].

  16. Enhanced Stability of All Solution-Processed Organic Thin-Film Transistors Using Highly Conductive Modified Polymer Electrodes

    Science.gov (United States)

    Han, Jeong In; Kim, Yong-Hoon; Park, Sung Kyu

    2012-09-01

    Enhanced stability of all solution-processed organic thin-film transistors (OTFTs) has been achieved by replacing metallic electrodes with glycerol-modified poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) polymer electrodes. The modified PEDOT:PSS showed a substantially low electrical resistivity of 6.4×10-3 Ω cm with improved environmental stability and water-resistant characteristics, which are crucial for highly reliable applications. Additionally, the modified PEDOT:PSS electrodes were highly stable under intense mechanical stress, allowing their application to flexible electronics. Particularly, all solution-processed flexible and transparent OTFTs with the modified PEDOT:PSS electrodes showed a field-effect mobility decrease of only 2.7% after a tensile mode mechanical fatigue test, while OTFTs with metallic electrodes showed a mobility decrease of 56.6% under identical test conditions.

  17. Process stabilization by dual focus laser welding of aluminum alloys for car body

    Science.gov (United States)

    Shibata, Kimihiro; Iwase, Takakuni; Sakamoto, Hiroki; Dausinger, Friedrich H.; Hohenberger, Bernd; Mueller, Matthias; Matsunawa, Akira; Seto, Naoki

    2003-09-01

    Aluminum alloys were welded using dual focus beams formed with two Nd:YAG lasers with the aim of obtaining a stable welding process. The relationship between the configuration of the spot beams and the quality of the weld beads was investigated using X-ray and high-speed camera observations. The number of pores was clearly related to the ratio of the keyhole depth to the keyhole opening. A larger keyhole opening and/or a shallower keyhole depth resulted in a smaller number of pores caused by instability of the weld pool. Based on the investigation, a car body component was welded with a dual focus beam system. The results show that aluminum car body panels can be welded stably at high speed with little distortion under optimum conditions.

  18. Enhanced stability of ZnO-based inverted organic photovoltaic devices by phosphonic acid modification

    Science.gov (United States)

    MacLeod, Bradley; Tremolet de Villers, Bertrand; Cowan, Sarah; Ratcliff, Erin; Olson, Dana

    2014-03-01

    Solution-processed ZnO thin films are now commonly used as n-type bottom contacts in inverted-geometry organic photovoltaics (OPVs). The use of ZnO eliminates the need for highly-reactive top-contact (air-interface) electrode material, such as calcium and aluminum which are commonly used in conventional geometries, which enables operational lifetimes of unencapsulated devices to shift from minutes or hours to days. Modification of the ZnO film by self-assembled monolayers (SAMs) has been shown to enhance performance as well as air-stability during storage. We modify ZnO with dipolar phosphonic acids and observe enhanced performance and stability. We show for the first time devices measured under continuous illumination at one-sun intensity which have significantly enhanced stability when utilizing SAM-modified ZnO. These continuous-illumination stability measurements allow us to investigate the degradation mechanisms of these more stable inverted OPV devices. This work was was supported by of the Center for Interface Science: Solar Electric Materials (CISSEM), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001084.

  19. Treatment of coke-oven wastewater with the powdered activated carbon-contact stabilization activated sludge process. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Suidan, M.T.; Deady, M.A.; Gee, C.S.

    1983-11-01

    The objective of the study was to determine optimum parameters for the operation of an innovative process train used in the treatment of coke-over wastewater. The treatment process train consisted of a contact-stabilization activated sludge system with powdered activated carbon (PAC) addition, followed by activated sludge nitrification, followed by denitrification in an anoxic filter. The control and operating parameters evaluated during the study were: (a) the average mixed-liquor PAC concentration maintained in the contact-stabilization system, (b) the solids retention time practiced in the contact-stabilization system, and (c) the hydraulic detention time maintained in the contact aeration tank. Three identical treatement process trains were constructed and employed in this study. The coke-oven wastewater used for this investigation was fed to the treatment units at 30% strength. The first part of the study was devoted to determining the interactions between the mixed liquor PAC concentration and the solids retention time in the contact-stabilization tanks. Results showed that optimum overall system performance is attainable when the highest sludge age (30 day) and highest mixed liquor PAC concentration were practiced. During the second phase of the study, all three systems were operated at a 30 day solids retention time while different detention times of 1, 2/3 and 1/3 day were evaluated in the contact tank. PAC addition rates were maintained at the former levels and, consequently, reduced contact times entailed higher mixed liquor carbon concentrations. Once again, the system receiving the highest PAC addition rate of PAC exhibited the best overall performance. This system exhibited no deterioration in process performance as a result of decreased contact detention time. 72 references, 41 figures, 24 tables.

  20. Improvement of a stability-indicating method by Quality-by-Design versus Quality-by-Testing: a case of a learning process.

    Science.gov (United States)

    Hubert, C; Lebrun, P; Houari, S; Ziemons, E; Rozet, E; Hubert, Ph

    2014-01-01

    The understanding of the method is a major concern when developing a stability-indicating method and even more so when dealing with impurity assays from complex matrices. In the presented case study, a Quality-by-Design approach was applied in order to optimize a routinely used method. An analytical issue occurring at the last stage of a long-term stability study involving unexpected impurities perturbing the monitoring of characterized impurities needed to be resolved. A compliant Quality-by-Design (QbD) methodology based on a Design of Experiments (DoE) approach was evaluated within the framework of a Liquid Chromatography (LC) method. This approach allows the investigation of Critical Process Parameters (CPPs), which have an impact on Critical Quality Attributes (CQAs) and, consequently, on LC selectivity. Using polynomial regression response modeling as well as Monte Carlo simulations for error propagation, Design Space (DS) was computed in order to determine robust working conditions for the developed stability-indicating method. This QbD compliant development was conducted in two phases allowing the use of the Design Space knowledge acquired during the first phase to define the experimental domain of the second phase, which constitutes a learning process. The selected working condition was then fully validated using accuracy profiles based on statistical tolerance intervals in order to evaluate the reliability of the results generated by this LC/ESI-MS stability-indicating method. A comparison was made between the traditional Quality-by-Testing (QbT) approach and the QbD strategy, highlighting the benefit of this QbD strategy in the case of an unexpected impurities issue. On this basis, the advantages of a systematic use of the QbD methodology were discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Effects of wet-granulation process parameters on the dissolution and physical stability of a solid dispersion.

    Science.gov (United States)

    Kinoshita, Ryo; Ohta, Tomoaki; Shiraki, Koji; Higashi, Kenjirou; Moribe, Kunikazu

    2017-05-30

    This study investigated how the process parameters of wet-granulation affect the properties of solid dispersions (SDs), such as dissolution and physical stability. SDs of nilvadipine (NIL) and hypromellose prepared by spray-drying were wet-granulated and dried under various conditions. The NIL concentration at 4h and area under the curve from dissolution tests were taken to indicate dissolution. Then, the NIL crystallinity calculated from powder X-ray diffraction patterns of SD granules stored at 60°C for 3 months was evaluated to indicate physical stability. A statistical analysis revealed that the amount of granulation liquid (w/w%) and the ratio of water to ethanol in the liquid (v/v%) significantly affected the dissolution property, and that the drying temperature had a significant effect on the physical stability. Although exposure to water makes the wet-granulation process seem less suitable for granulating a SD, the results indicated that the process can be used to develop SD granules by selecting appropriate conditions, such as a lower proportion of granulation liquid, a higher water to ethanol ratio in the liquid, and a higher drying temperature. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. [Comparison of fixation effects of heavy metals between cement rotary kiln co-processing and cement solidification/stabilization].

    Science.gov (United States)

    Zhang, Jun-li; Liu, Jian-guo; Li, Cheng; Jin, Yi-ying; Nie, Yong-feng

    2008-04-01

    Both cement rotary kiln co-processing hazardous wastes and cement solidification/stabilization could dispose heavy metals by fixation. Different fixation mechanisms lead to different fixation effects. The same amount of heavy metal compounds containing As, Cd, Cr, Cu, Pb, Zn were treated by the two kinds of fixation technologies. GB leaching test, TCLP tests and sequential extraction procedures were employed to compare the fixation effects of two fixation technologies. The leached concentration and chemical species distribution of heavy metals in two grounded mortar samples were analyzed and the fixation effects of two kinds of technologies to different heavy metals were compared. The results show the fixation effect of cement rotary kiln co-processing technology is better than cement solidification/stabilization technology to As, Pb, Zn. Calcinations in cement rotary kiln and then hydration help As, Pb, Zn contained in hazardous wastes transform to more steady chemical species and effectively dispose these heavy metals compounds. Cr3+ is liable to be converted to much more toxic and more mobile Cr6+ state in cement rotary kiln. And so Cr wastes are more fit for treatment by cement solidification/stabilization technology. The work could provide a basis when choosing disposal technologies for different heavy metals and be helpful to improve the application and development of cement rotary kiln co-processing hazardous wastes.

  3. Small hazardous waste generators in developing countries: use of stabilization/solidification process as an economic tool for metal wastewater treatment and appropriate sludge disposal.

    Science.gov (United States)

    Silva, Marcos A R; Mater, Luciana; Souza-Sierra, Maria M; Corrêa, Albertina X R; Sperb, Rafael; Radetski, Claudemir M

    2007-08-25

    The aim of this study was to propose a profitable destination for an industrial sludge that can cover the wastewater treatment costs of small waste generators. Optimized stabilization/solidification technology was used to treat hazardous waste from an electroplating industry that is currently released untreated to the environment. The stabilized/solidified (S/S) waste product was used as a raw material to build concrete blocks, to be sold as pavement blocks or used in roadbeds and/or parking lots. The quality of the blocks containing a mixture of cement, lime, clay and waste was evaluated by means of leaching and solubility tests according to the current Brazilian waste regulations. Results showed very low metal leachability and solubility of the block constituents, indicating a low environmental impact. Concerning economic benefits from the S/S process and reuse of the resultant product, the cost of untreated heavy metal-containing sludge disposal to landfill is usually on the order of US$ 150-200 per tonne of waste, while 1tonne of concrete roadbed blocks (with 25% of S/S waste constitution) has a value of around US$ 100. The results of this work showed that the cement, clay and lime-based process of stabilization/solidification of hazardous waste sludge is sufficiently effective and economically viable to stimulate the treatment of wastewater from small industrial waste generators.

  4. Laterite Based Stabilized Products for Sustainable Building Applications in Tropical Countries: Review and Prospects for the Case of Cameroon

    Directory of Open Access Journals (Sweden)

    Arlin B. Tchamba

    2011-01-01

    Full Text Available Lateritic soils are formed in the tropics through weathering processes that favor the formation of iron, aluminum, manganese and titanium oxides. These processes break down silicate minerals into clay minerals such as kaolinite and illite. Iron and aluminum oxides are prominent in lateritic soils, and with the seasonal fluctuation of the water table, these oxides result in the reddish-brown color that is seen in lateritic soils. These soils have served for a long time as major and sub-base materials for the construction of most highways and walls of residential houses in tropical and sub-tropical countries of the world. Civil engineering applications of these lateritic soils are continually being developed with the use of different types of stabilizers. The stabilized soil-based products are as such viewed as environmentally-friendly and low-cost energy materials for sustainable building applications. This work aims at presenting a global view of what has been done in the field of lateritic soil improvement for construction purposes in tropical countries such as Cameroon. This shall be discussed through the presentation of the structure, composition and properties of lateritic soils, the various ways of improving their properties for construction purposes, the properties of products obtained and other prospects.

  5. A general model for membrane-based separation processes

    DEFF Research Database (Denmark)

    Soni, Vipasha; Abildskov, Jens; Jonsson, Gunnar Eigil

    2009-01-01

    behaviour will play an important role. In this paper, modelling of membrane-based processes for separation of gas and liquid mixtures are considered. Two general models, one for membrane-based liquid separation processes (with phase change) and another for membrane-based gas separation are presented....... The separation processes covered are: membrane-based gas separation processes, pervaporation and various types of membrane distillation processes. The specific model for each type of membrane-based process is generated from the two general models by applying the specific system descriptions and the corresponding......A separation process could be defined as a process that transforms a given mixture of chemicals into two or more compositionally distinct end-use products. One way to design these separation processes is to employ a model-based approach, where mathematical models that reliably predict the process...

  6. Stability optimisation of molecular electronic devices based on  nanoelectrode–nanoparticle bridge platform in air and different storage liquids

    International Nuclear Information System (INIS)

    Jafri, S. H. M.; Blom, T.; Wallner, A.; Ottosson, H.; Leifer, K.

    2014-01-01

    The long-term stability of metal nanoparticle–molecule junctions in molecular electronic devices based on nanoelectrodes (NEL) is a major challenge in the effort to bring related molecular electronic devices to application. To optimize the reproducibility of molecular electronic nanodevices, the time-dependent modification of such junctions as exposed to different media needs to be known. Here, we have studied (1) the stability of Au-NEL and (2) the electrical stability of molecule–Au nanoparticle (AuNP) junctions themselves with the molecule being  1,8-octanedithiol (ODT). Both the NELs only and the junctions were exposed to air and liquids such as deionized water, tetrahydrofuran, toluene and tetramethylethylenediamine (TMEDA) over a period of 1 month. The nanogaps remained stable in width when stored in either deionized water or toluene, whereas the current through 1,8-octanedithiol–NP junctions remained most stable when stored in TMEDA as compared to other solvents. Although it is difficult to follow the chemical processes in such devices in the 10-nm range with analytical methods, the behavior can be interpreted from known interactions of solvent molecules with electrodes and ODT

  7. CSER 00-003: Criticality Safety Evaluation report for PFP Magnesium Hydroxide Precipitation Process for Plutonium Stabilization Glovebox 3

    International Nuclear Information System (INIS)

    LAN, J.S.

    2000-01-01

    This Criticality Safety Evaluation Report analyzes the stabilization of plutonium/uranium solutions in Glovebox 3 using the magnesium hydroxide precipitation process at PFP. The process covered are the receipt of diluted plutonium solutions into three precipitation tanks, the precipitation of plutonium from the solution, the filtering of the plutonium precipitate from the solution, the scraping of the precipitate from the filter into boats, and the initial drying of the precipitated slurry on a hot plate. A batch (up to 2.5 kg) is brought into the glovebox as plutonium nitrate, processed, and is then removed in boats for further processing. This CSER establishes limits for the magnesium hydroxide precipitation process in Glovebox 3 to maintain criticality safety while handling fissionable material

  8. Dynamic Characteristics Analysis and Stabilization of PV-Based Multiple Microgrid Clusters

    DEFF Research Database (Denmark)

    Zhao, Zhuoli; Yang, Ping; Wang, Yuewu

    2018-01-01

    As the penetration of PV generation increases, there is a growing operational demand on PV systems to participate in microgrid frequency regulation. It is expected that future distribution systems will consist of multiple microgrid clusters. However, interconnecting PV microgrids may lead to system...... interactions and instability. To date, no research work has been done to analyze the dynamic behavior and enhance the stability of microgrid clusters considering the dynamics of the PV primary sources and dc links. To fill this gap, this paper presents comprehensive modeling, analysis, and stabilization of PV......-based multiple microgrid clusters. A detailed small-signal model for PV-based microgrid clusters considering local adaptive dynamic droop control mechanism of the voltage-source PV system is developed. The complete dynamic model is then used to access and compare the dynamic characteristics of the single...

  9. Enhanced Stability of DNA Nanostructures by Incorporation of Unnatural Base Pairs.

    Science.gov (United States)

    Liu, Qing; Liu, Guocheng; Wang, Ting; Fu, Jing; Li, Rujiao; Song, Linlin; Wang, Zhen-Gang; Ding, Baoquan; Chen, Fei

    2017-11-03

    Self-assembled DNA nanostructures hold great promise in the fields of nanofabrication, biosensing and nanomedicine. However, the inherent low stability of the DNA double helices, formed by weak interactions, largely hinders the assembly and functions of DNA nanostructures. In this study, we redesigned and constructed a six-arm DNA junction by incorporation of the unnatural base pairs 5-Me-isoC/isoG and A/2-thioT into the double helices. They not only retained the structural integrity of the DNA nanostructure, but also showed enhanced thermal stability and resistance to T7 Exonuclease digestion. This research may expand the applications of DNA nanostructures in nanofabrication and biomedical fields, and furthermore, the genetic alphabet expansion with unnatural base pairs may enable us to construct more complicated and diversified self-assembled DNA nanostructures. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Study on transient stability of wind turbine with induction generator based on variable pitch control strategy

    DEFF Research Database (Denmark)

    Zhao, B.; Li, H.; Han, L.

    2011-01-01

    In order to enhance and improve the transient stability of a grid-connected wind turbine generator system under the power grid fault, based on typical pitch control strategy of wind turbine, considering the wind turbine system oscillation caused by the drive-train shaft flexibility, Based on Matlab....../Simulink, electromagnetic transient state models of the wind tubine generator system and the pitch control models were presented, and the transient behaviors of the wind turbine genarator system using the typical and the proposed pitch control strategies were analyzed and compared when the power grid was subjected...... to a three-phase short-circuit fault. Also the results were compared with using reactive compensation device. The simulation results show that the proposed pitch control strategy can effectively improve the transient stability of wind turbine generator system....

  11. Site selection of active damper for stabilizing power electronics based power distribution system

    DEFF Research Database (Denmark)

    Yoon, Changwoo; Wang, Xiongfei; Bak, Claus Leth

    2015-01-01

    Stability in the nowadays distribution power system is endangered by interaction problems that may arise from newly added power-electronics based power devices. Recently, a new concept to deal with this higher frequency instability, the active damper, has been proposed. The active damper is a power...... point when the system has many nodes. Therefore, this paper addresses the proper placement of an active damper in an unstable small-scale power distribution system. A time-domain model of the Cigre benchmark low-vltage network is used as a test field. The result shows the active damper location...... electronics based power device, which provides an adjustable damping capability to the power system where the voltage harmonic instability is measured. It can stabilize by adjusting the equivalent node impedance with its plug and play feature. This feature gives many degrees of freedom of its installation...

  12. Study on transient stability of wind turbine with induction generator based on variable pitch control strategy

    DEFF Research Database (Denmark)

    Zhao, B.; Li, H.; Han, L.

    2011-01-01

    In order to enhance and improve the transient stability of a grid-connected wind turbine generator system under the power grid fault, based on typical pitch control strategy of wind turbine, considering the wind turbine system oscillation caused by the drive-train shaft flexibility, Based on Matlab...... to a three-phase short-circuit fault. Also the results were compared with using reactive compensation device. The simulation results show that the proposed pitch control strategy can effectively improve the transient stability of wind turbine generator system......./Simulink, electromagnetic transient state models of the wind tubine generator system and the pitch control models were presented, and the transient behaviors of the wind turbine genarator system using the typical and the proposed pitch control strategies were analyzed and compared when the power grid was subjected...

  13. State-space-based harmonic stability analysis for paralleled grid-connected inverters

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Chen, Zhe

    2016-01-01

    This paper addresses a state-space-based harmonic stability analysis of paralleled grid-connected inverters system. A small signal model of individual inverter is developed, where LCL filter, the equivalent delay of control system, and current controller are modeled. Then, the overall small signal...... model of paralleled grid-connected inverters is built. Finally, the state space-based stability analysis approach is developed to explain the harmonic resonance phenomenon. The eigenvalue traces associated with time delay and coupled grid impedance are obtained, which accounts for how the unstable...... inverter produces the harmonic resonance and leads to the instability of whole paralleled system. The proposed approach reveals the contributions of the grid impedance as well as the coupled effect on other grid-connected inverters under different grid conditions. Simulation and experimental results...

  14. Effects of different encapsulation agents and drying process on stability of betalains extract.

    Science.gov (United States)

    Ravichandran, Kavitha; Palaniraj, Ravichandran; Saw, Nay Min Min Thaw; Gabr, Ahmed M M; Ahmed, Abdelrahman R; Knorr, Dietrich; Smetanska, Iryna

    2014-09-01

    Red beet plants are rich in betalains that can be used as food natural colorants. Betalains were extracted from red beet and encapsulated with different carrier agents and freeze or spray dried. Effect of different encapsulating agents as maltodextrin, guar gum, gum Arabic, pectin and xanthan gum with different concentration (as encapsulating agents) were studied on the betalain stability. Encapsulated betalains with xanthan gum with maltodextrin showed about 65 % more recovery than the control. Encapsulation showed a higher recovery of betalains during freeze drying by 1.3 times than during spray drying. Spray dried samples has L* (lightness) higher than the freeze dried samples. The variations of maltodextrin with xanthan and guar gum freeze dried have highest chroma value of 21. The stabilization of pure betalain pigments may boost the use of these colouring molecules in the food industry and promote their application.

  15. Verb-based anticipatory processing in aphasia

    Directory of Open Access Journals (Sweden)

    Michael Walsh Dickey

    2015-05-01

    Full Text Available Healthy listeners use verb and agent+verb constraints to anticipate likely arguments (Altmann & Kamide, 1999; Kamide et al., 2003. Listeners also show early looks to unlikely but possible arguments (Boland, 2005; Borovsky, et al., 2012, suggesting that coarse-grained verb-based semantic constraints may influence early processing (Kuperberg, 2013. This study investigated the roles of verb and agent+verb constraints on expectations about likely and unlikely arguments in people with aphasia (PWA and healthy age-matched controls. In two visual-world experiments, PWA (n=9 and older adults (n=27 heard sentences truncated at the determiner and clicked on the image that “best finished” the sentence (Mack, et al, 2013. In Experiment 1, sentences with a semantically-constraining vs. unconstraining verb (Someone will eat/move the … were accompanied by images of: a likely target (cake, an unlikely but possible competitor (branch, and two unrelated impossible distractors (pail, van. In Experiment 2, sentences with a semantically-constraining vs. unconstraining agent+verb combination (The dog/Someone will drink the … were accompanied by: a likely target (water, an unlikely but possible competitor (coffee, a semantically-related impossible distractor (cat – semantic associate of constraining agent, and an unrelated impossible distractor (rocks. By-participants and by-items ANOVAs showed that likelihood guided looks for both participant groups in both experiments. In the constrained condition in Experiment 1, gaze proportion was reliably higher to the target (cake than the two impossible distractors (pail, van, with controls showing this effect in a 400-ms bin starting 400 ms after verb onset (Fig1a and PWA approximately 400ms later, in a 400-ms bin starting 800 ms after verb onset (Fig1b. During the same time windows in the constrained condition in Experiment 2, both groups were more likely to gaze at the target (water than the unlikely competitor

  16. Effects of different encapsulation agents and drying process on stability of betalains extract

    OpenAIRE

    Ravichandran, Kavitha; Palaniraj, Ravichandran; Saw, Nay Min Min Thaw; Gabr, Ahmed M. M.; Ahmed, Abdelrahman R.; Knorr, Dietrich; Smetanska, Iryna

    2012-01-01

    Red beet plants are rich in betalains that can be used as food natural colorants. Betalains were extracted from red beet and encapsulated with different carrier agents and freeze or spray dried. Effect of different encapsulating agents as maltodextrin, guar gum, gum Arabic, pectin and xanthan gum with different concentration (as encapsulating agents) were studied on the betalain stability. Encapsulated betalains with xanthan gum with maltodextrin showed about 65 % more recovery than the contr...

  17. Stability of phenolic compounds of the propolis processed by ionizing radiation

    International Nuclear Information System (INIS)

    Matsuda, Andrea H.; Mastro, Nelida L. del

    2002-01-01

    Propolis is the generic term of a resin of different colors and consistency collected by bees, Apis mellifera, from diverse parts of plants, buds and resinous exudates. It possesses antibacterial , antifungal and antiviral properties and many other biological activities such as antiinflammatory, antiulcer, local anaesthetic, antitumor, etc. The aim of this work is to study the effect of 60 Co ionizing radiation on the stability of phenolic compounds of propolis. (author)

  18. Effect of extraction process on composition, oxidative stability and rheological properties of purslane seed oil.

    Science.gov (United States)

    Delfan-Hosseini, Sasan; Nayebzadeh, Kooshan; Mirmoghtadaie, Leila; Kavosi, Maryam; Hosseini, Seyede Marzieh

    2017-05-01

    Purslane seed oil could be considered as potential nutritious oil due to its desirable fatty acid composition and other biological active compounds. In this study the effect of three extraction procedure including solvent extraction, cold pressing and microwave pretreatment (MW) followed by cold pressing on oil yield, physicochemical properties, oxidative stability and rheological behaviors of oil was investigated. Solvent extracted oil had the highest extraction yield (72.31%). Pretreatment by microwave before cold press extraction resulted in an increase in extraction yield, total phenolic compound (TPC) and antioxidant activity. Cold press extracted oil had the lowest oxidative stability (4.64h). This property was greatly enhanced by microwave irradiation, so that the longest oxidative stability was found in MW-cold press extracted oil with 9.67h. Furthermore, all extracted oils demonstrated Newtonian flow behaviors. MW-cold press extracted oil had the greatest apparent viscosity and highest sensitivity to temperature changes (E a =29.18kJ/mol -1 ). Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Stability Analysis of a Microgrid System based on Inverter-Interfaced Distributed Generators

    Directory of Open Access Journals (Sweden)

    CUSIDO, J.

    2013-08-01

    Full Text Available This paper presents a phase-plane trajectory analysis and the appliance of Lyapunov's methodology to evaluate the stability limits of a small signal model of a Microgrid system. The work done is based on a non-linear tool and several computer simulations. The study indicates how to analyze a Microgrid system that is subjected to a severe transient disturbance by using its large signal model without the necessity of the small signal analysis as it is commonly applied.

  20. THE EFFECTS OF PILATES BASED CORE STABILITY TRAINING IN PEOPLE WITH MS

    OpenAIRE

    Fox, Esther Elizabeth

    2015-01-01

    Background: People with Multiple Sclerosis experience difficulties with balance and mobility. Pilates exercises are often used to address these difficulties. Design: This was a multi-centre, double blind, block randomised, controlled trial. Eligible participants were recruited from seven UK centres. Participants were randomly allocated to either: Pilates based core stability training (Pilates), Standardised Exercise (SE) or Relaxation (placebo). All received face-to-face training session...

  1. Standard Test Method for Preparing Aircraft Cleaning Compounds, Liquid Type, Water Base, for Storage Stability Testing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This test method covers the determination of the stability in storage, of liquid, water-base chemical cleaning compounds, used to clean the exterior surfaces of aircraft. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  2. A novel method for prokaryotic promoter prediction based on DNA stability

    OpenAIRE

    Kanhere, Aditi; Bansal, Manju

    2005-01-01

    Abstract Background In the post-genomic era, correct gene prediction has become one of the biggest challenges in genome annotation. Improved promoter prediction methods can be one step towards developing more reliable ab initio gene prediction methods. This work presents a novel prokaryotic promoter prediction method based on DNA stability. Results The promoter region is less stable and hence more prone to melting as compared to other genomic regions. Our analysis shows that a method of promo...

  3. Stability of Electrical Characteristics of MOS Structures Based on Gallium Oxide

    Science.gov (United States)

    Kalygina, V. M.; Petrova, Yu. S.; Prudaev, I. A.; Tolbanov, O. P.

    2016-10-01

    We present the results of studying the capacitance-voltage and conductance-voltage characteristics of the GaxOy/ GaAs-based metal - oxide - semiconductor structures obtained by thermal evaporation. Influence of the annealing temperature on the characteristics of the structures is established. It is found that at long-term storage in the room atmosphere, the structures do not change their properties, which is manifested in the stability of electrical characteristics.

  4. Low-cost sliding mode control of WECS based on DFIG with stability analysis

    OpenAIRE

    DJOUDI, ABDELHAK; CHEKIREB, HACHEMI; BERKOUK, EL MADJID; BACHA, SEDDIK

    2015-01-01

    The aim of this work is to developing sliding mode control of active and reactive stator powers produced by a wind energy conversion system (WECS), based on doubly fed induction generator (DFIG). A flux estimation model and rotor current sensor are no longer required. The controller is developed from the DFIG nonlinear-coupled model. Moreover, the global stability and the DFIG states' boundedness when our low-cost sliding mode control is applied are established analytically. It is re...

  5. A Novel Fuzzy Logic Based Power System Stabilizer for a Multimachine System

    OpenAIRE

    Singh, Anup; Sen, Indraneel

    2003-01-01

    This paper describes the design of a Fuzzy logic based controller to counter the small signal oscillatory instability in power system. The stabilizing signal is computed in real time using suitable fuzzy membership functions depending upon the state of the generator on the speed-acceleration phase plane. The use of output membership function permits further fine tuning of the controller parameters for varied system configurations specially in multimachine environment. The efficacy of the p...

  6. Design of a fuzzy-logic-control-based robust power system stabilizer

    Science.gov (United States)

    Zhao, Hui; Liu, Lu-yuan; Wang, Hong-jun; Yue, You-jun

    2008-10-01

    This paper presents a design procedure for a robust power system stabilizer(RPSS) based on fuzzy logic control techniques. Speed deviation of a synchronous generator and its derivative are chosen as the input signals of RPSS. A normalized sum-squared deviation(NSSD) index is used to design the RPSS and investigate the robustness of the RPSS for a multi-machine power system. Nonlinear simulation tests under different disturbances are given and their results are discussed.

  7. Multi-stage Fuzzy Power System Stabilizer Based on Modified Shuffled Frog Leaping Algorithm

    OpenAIRE

    Yousefi, Nasser

    2015-01-01

    This paper presents a new strategy based on Multi-stage Fuzzy (MSF) PID controller for damping Power System Stabilizer (PSS) in multi-machine environment using Modified Shuffled Frog Leaping (MSFL) algorithm. The proposed technique is a new meta-heuristic algorithm which is inspired by mating procedure of the honey bee. Actually, the mentioned algorithm is used recently in power systems which demonstrate the good reflex of this algorithm. Also, finding the parameters of PID controller in powe...

  8. Transducer-based fiber Bragg grating high-temperature sensor with enhanced range and stability

    Science.gov (United States)

    Mamidi, Venkata Reddy; Kamineni, Srimannarayana; Ravinuthala, Lakshmi Narayana Sai Prasad; Tumu, Venkatappa Rao

    2017-09-01

    Fiber Bragg grating (FBG)-based high-temperature sensor with enhanced-temperature range and stability has been developed and tested. The sensor consists of an FBG and a mechanical transducer, which furnishes a linear temperature-dependent tensile strain on FBG by means of differential linear thermal expansion of two different ceramic materials. The designed sensor is tested over a range: 20°C to 1160°C and is expected to measure up to 1500°C.

  9. Processed beetroot (Beta vulgaris L.) as a natural antioxidant in mayonnaise: Effects on physical stability, texture and sensory attributes

    OpenAIRE

    Vassilios Raikos; Angela McDonagh; Viren Ranawana; Garry Duthie

    2016-01-01

    The oxidative and physical stability of the reformulated mayonnaise with processed beetroot was investigated and compared with a control (mayonnaise without beetroot) and a commercially available product. Processing of beetroot had an impact on the structural integrity of the antioxidants present. Microwaving (960 W for 7 min) was advantageous for preserving the betalain and polyphenol content of beetroot compared to roasting (180 °C for 90 min) and boiling (100 °C for 30 min). The oxidative ...

  10. Enhancement of temozolomide stability by loading in chitosan-carboxylated polylactide-based nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Di Martino, Antonio; Kucharczyk, Pavel; Capakova, Zdenka; Humpolicek, Petr; Sedlarik, Vladimir, E-mail: sedlarik@ft.utb.cz [Tomas Bata University in Zlín, Centre of Polymer Systems, University Institute (Czech Republic)

    2017-02-15

    In the presented work, amphiphilic nanoparticles based on chitosan and carboxy-enriched polylactic acid have been prepared to improve the stability of the pro-drug temozolomide in physiological media by encapsulation. The carrier, with a diameter in the range of 150–180 nm, was able to accommodate up to 800 μg of temozolomide per mg of polymer. The obtained formulation showed good stability in physiological condition and preparation media up to 1 month. Temozolomide loaded inside the carrier exhibited greater stability than the free drug, in particular in simulated physiological solution at pH 7.4 where the hydrolysis in the inactive metabolite was clearly delayed. CS-SPLA nanoparticles demonstrated a pH-dependent TMZ release kinetics with the opportunity to increase or decrease the rate. Mass spectroscopy, UV-Vis analysis, and in vitro cell tests confirmed the improvement in temozolomide stability and effectiveness when loaded into the polymeric carrier, in comparison with the free drug.

  11. Mechanism of Degradation and Improvement of Stability on Mesogenic-Phthalocyanine-Based Bulk Heterojunction Solar Cell

    Science.gov (United States)

    Duy Dao, Quang; Hori, Tetsuro; Masuda, Tetsuya; Fukumura, Kaoru; Kamikado, Toshiya; Nekelson, Fabien; Fujii, Akihiko; Shimizu, Yo; Ozaki, Masanori

    2013-01-01

    The stability of bulk heterojunction organic solar cells utilizing the phthalocyanine derivative 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2) and the fullerene derivative 1-(3-methoxy-carbonyl)-propyl-1-1-phenyl-(6,6)C61 has been studied. In the same environment, C6PcH2-based cells have shown higher stability than the cells fabricated using the conventional donor material poly(3-hexylthiophene). Furthermore, the degradation mechanisms of these solar cells have been investigated. It was found that the chemical bonds of two pyrrole aza nitrogens as well as the four mesobridging aza nitrogens with neighboring carbons in the C6PcH2 molecule were broken after irradiation with a solar simulator, which affected the device lifetime. To improve the stability, various buffer layers have been deposited between the counterelectrode and the active layer. Obviously, the C60 thin film and the oxidized layer play an important role as blocking layers that prevent the diffusion of metal atoms into the active layer, resulting in the higher stability.

  12. Correlation between local structure and stability of supercooled liquid state in Zr-based metallic glasses

    International Nuclear Information System (INIS)

    Saida, Junji; Imafuku, Muneyuki; Sato, Shigeo; Sanada, Takashi; Matsubara, Eiichiro; Inoue, Akihisa

    2007-01-01

    The correlation between the local structure and stability of supercooled liquid state is investigated in the Zr 70 (Ni, Cu) 30 binary and Zr 70 Al 10 (Ni, Cu) 20 (numbers indicate at.%) ternary metallic glasses. The Zr 70 Ni 30 binary amorphous alloy with a low stability of supercooled liquid state has a tetragonal Zr 2 Ni-like local structure around Ni atom. Meanwhile, the Zr 70 Cu 30 binary metallic glass has a different local structure of tetragonal Zr 2 Cu, where we suggest the icosahedral local structure by the quasicrystallization behavior in addition of a very small amount of noble metals. The effect of Al addition on the local structure in the Zr-Ni alloy is also examined. We have investigated that the dominant local structure changes in the icosahedral-like structure from the tetragonal Zr 2 Ni-like local structure by the Al substitution with Ni accompanying with the significant stabilization of supercooled liquid state. It is concluded that the formation of icosahedral local structure contributes to the enhancement of stability of supercooled liquid state in the Zr-based alloys

  13. Implicit Schemata and Categories in Memory-Based Language Processing

    Science.gov (United States)

    van den Bosch, Antal; Daelemans, Walter

    2013-01-01

    Memory-based language processing (MBLP) is an approach to language processing based on exemplar storage during learning and analogical reasoning during processing. From a cognitive perspective, the approach is attractive as a model for human language processing because it does not make any assumptions about the way abstractions are shaped, nor any…

  14. A novel method for prokaryotic promoter prediction based on DNA stability.

    Science.gov (United States)

    Kanhere, Aditi; Bansal, Manju

    2005-01-05

    In the post-genomic era, correct gene prediction has become one of the biggest challenges in genome annotation. Improved promoter prediction methods can be one step towards developing more reliable ab initio gene prediction methods. This work presents a novel prokaryotic promoter prediction method based on DNA stability. The promoter region is less stable and hence more prone to melting as compared to other genomic regions. Our analysis shows that a method of promoter prediction based on the differences in the stability of DNA sequences in the promoter and non-promoter region works much better compared to existing prokaryotic promoter prediction programs, which are based on sequence motif searches. At present the method works optimally for genomes such as that of Escherichia coli, which have near 50 % G+C composition and also performs satisfactorily in case of other prokaryotic promoters. Our analysis clearly shows that the change in stability of DNA seems to provide a much better clue than usual sequence motifs, such as Pribnow box and -35 sequence, for differentiating promoter region from non-promoter regions. To a certain extent, it is more general and is likely to be applicable across organisms. Hence incorporation of such features in addition to the signature motifs can greatly improve the presently available promoter prediction programs.

  15. Stability analysis in a ROADM-based multi-channel quasi-ring optical network

    Science.gov (United States)

    Tsai, Jimmy; Wang, Zheng; Pan, Yan; Kilper, Daniel C.; Pavel, Lacra

    2015-01-01

    Future networks require dynamic physical layer capabilities to enable rapid and on-demand reconfiguration, while ensuring stability. This paper addresses stability analysis of a ROADM-based quasi-ring optical network. A ROADM-based quasi-ring is the simplest configuration in which channel power excursions can self-propagate indefinitely and be unstable. This network configuration is composed of two reconfigurable optical add-drop multiplexers (ROADMs) each equipped with a constant gain optical amplifier and a wavelength selective switch. Over the amplified spans, two sets of lightpaths (added/dropped by opposite ROADMs) are transmitted in mirror image of each other and form an overlapping ring. Sufficient stability conditions for the quasi-ring as well as an L2 bound for the channel power excursions are derived based on Lyapunov analysis and the small gain theorem. These conditions are functions of the amplifier gain coupling quantified by its Lipschitz constant. Numerical results that verify and compare the theoretical results are provided. The platform used is Bell Lab's A Transparent Optical Mesh (ATOM) simulator, set up for dynamic network loading and input channel disturbance scenarios.

  16. Ca stabilized zirconia based composites by wet consolidation of zirconia and high alumina cement mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Bruni, Y.L.; Garrido, L.B.; Aglietti, E.F., E-mail: lgarrido@cetmic.unlp.edu.ar [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC/CIC-CONICET La Plata), Buenos Aires (Argentina)

    2012-07-01

    Composites of the CaO-Al{sub 2}O{sub 3}-ZrO{sub 2} system are widely used in many industrial applications. In this study, porous Ca stabilized ZrO{sub 2} composites were developed from a starting mixture of m-ZrO{sub 2} and calcium aluminate cement. Ceramics were produced by wet consolidation of aqueous suspensions with and without corn starch as pore former agent and sintering at 1000-1500 °C. The influence of processing parameters on crystalline phases, sintering behavior and textural characteristics was examined. Stabilized c-ZrO{sub 2} formed with the composition of Ca{sub 0.15}Zr{sub 0.85}O{sub 1.85}. The sintering of the mixtures lead to porous composites materials. Textural properties were analyzed considering the initial composition and the present crystalline phases. (author)

  17. Photocatalytic Based Degradation Processes of Lignin Derivatives

    Directory of Open Access Journals (Sweden)

    Colin Awungacha Lekelefac

    2015-01-01

    Full Text Available Photocatalysis, belonging to the advanced oxidation processes (AOPs, is a potential new transformation technology for lignin derivatives to value added products (e.g., phenol, benzene, toluene, and xylene. Moreover, lignin represents the only viable source to produce aromatic compounds as fossil fuel alternative. This review covers recent advancement made in the photochemical transformation of industrial lignins. It starts with the photochemical reaction principle followed by results obtained by varying process parameters. In this context, influences of photocatalysts, metal ions, additives, lignin concentration, and illumination intensity and the influence of pH are presented and discussed. Furthermore, an overview is given on several used process analytical methods describing the results obtained from the degradation of lignin derivatives. Finally, a promising concept by coupling photocatalysis with a consecutive biocatalytic process was briefly reviewed.

  18. Stability of Chokeberry Bioactive Polyphenols during Juice Processing and Stabilization of a Polyphenol-Rich Material from the By-Product

    Directory of Open Access Journals (Sweden)

    Diana Behsnilian

    2012-09-01

    Full Text Available Chokeberries (Aronia melanocarpa are nowadays believed to exhibit potential cardioprotective and antidiabetic effects principally due to their high content in bioactive phenolic compounds. The stability of the phenolic compounds was studied during different stages of a juice production line and a method for the valorization of pomace was evaluated. Samples were taken from a commercial juice production plant, extracted and analyzed for phenolic constituents and antioxidant potential. Prototypes of functional food ingredients were produced from the pomace by wet milling and micro-milling. Alongside juice processing, the contents of phenolic berry constituents did not vary to a great extent and the overall antioxidant activity increased by about 34%. A high quality juice and a by-product still rich in polyphenols resulted from the process. The phenolic compounds content and the overall antioxidant activity remained stable when milling and micro-milling the pomace. During coarse milling, extractability of total phenolic compounds increased significantly (40% to 50%. Nanosized materials with averaged particle sizes (x50,0 of about 90 nm were obtained by micro-milling. These materials showed significantly enhanced extractability of total phenolic compounds (25% and total phenolic acid (30%, as well as antioxidant activity (35%, with unchanged contents of total procyanidins and anthocyanins contents.

  19. Sustainable Process Design of Lignocellulose based Biofuel

    DEFF Research Database (Denmark)

    Mangnimit, Saranya; Malakul, Pomthong; Gani, Rafiqul

    available, and are also non-food crops. In this respect, Cassava rhizome has several characteristics that make it a potential feedstock for fuel ethanol production. It has high content of cellulose and hemicelluloses . The objective of this paper is to present a study focused on the sustainable process....... The final process design includes 39 unit operations, has a capacity of 150,000 L/day and produces dry ethanol (approximately 13.0% of cassava rhizome is converted to ethanol)...

  20. TRIM39 is a MOAP-1-binding protein that stabilizes MOAP-1 through inhibition of its poly-ubiquitination process.

    Science.gov (United States)

    Lee, San San; Fu, Nai Yang; Sukumaran, Sunil K; Wan, Kah Fei; Wan, Qian; Yu, Victor C

    2009-04-15

    Bax, a multi-domain pro-apoptotic Bcl-2 family member, is a key regulator for the release of apoptogenic factors from mitochondria. MOAP-1, which was first isolated from a screen for Bax-associating proteins, interacts with Bax upon apoptotic induction. MOAP-1 is a short-lived protein that is constitutively degraded by the ubiquitin-proteasome system. Apoptotic stimuli upregulate MOAP-1 rapidly through inhibition of its poly-ubiquitination process. However, cellular factors that regulate the stability of MOAP-1 have not yet been identified. In this study, we report the identification of TRIM39 as a MOAP-1-binding protein. TRIM39 belongs to a family of proteins characterized by a Tripartite Motif (TRIM), consisting of RING domain, B-box and coiled-coil domain. Several TRIM family members are known to demonstrate E3 ubiquitin ligase activity. Surprisingly, TRIM39 significantly extends the half-life of MOAP-1 by inhibiting its poly-ubiquitination process. In agreement with its effect on enhancing MOAP-1 stability, TRIM39 sensitizes cells to etoposide-induced apoptosis. Conversely, knockdown of TRIM39 reduces the sensitivity of cells to etoposide-stimulated apoptosis. Furthermore, TRIM39 elevates the level of MOAP-1 in mitochondria and promotes cytochrome c release from isolated mitochondria stimulated by recombinant Bax. Together, these data suggest that TRIM39 can promote apoptosis signalling through stabilization of MOAP-1.

  1. On Intelligent Design and Planning Method of Process Route Based on Gun Breech Machining Process

    Science.gov (United States)

    Hongzhi, Zhao; Jian, Zhang

    2018-03-01

    The paper states an approach of intelligent design and planning of process route based on gun breech machining process, against several problems, such as complex machining process of gun breech, tedious route design and long period of its traditional unmanageable process route. Based on gun breech machining process, intelligent design and planning system of process route are developed by virtue of DEST and VC++. The system includes two functional modules--process route intelligent design and its planning. The process route intelligent design module, through the analysis of gun breech machining process, summarizes breech process knowledge so as to complete the design of knowledge base and inference engine. And then gun breech process route intelligently output. On the basis of intelligent route design module, the final process route is made, edited and managed in the process route planning module.

  2. Monocular distance estimation with optical flow maneuvers and efference copies: a stability-based strategy.

    Science.gov (United States)

    de Croon, Guido C H E

    2016-01-07

    The visual cue of optical flow plays an important role in the navigation of flying insects, and is increasingly studied for use by small flying robots as well. A major problem is that successful optical flow control seems to require distance estimates, while optical flow is known to provide only the ratio of velocity to distance. In this article, a novel, stability-based strategy is proposed for monocular distance estimation, relying on optical flow maneuvers and knowledge of the control inputs (efference copies). It is shown analytically that given a fixed control gain, the stability of a constant divergence control loop only depends on the distance to the approached surface. At close distances, the control loop starts to exhibit self-induced oscillations. The robot can detect these oscillations and hence be aware of the distance to the surface. The proposed stability-based strategy for estimating distances has two main attractive characteristics. First, self-induced oscillations can be detected robustly by the robot and are hardly influenced by wind. Second, the distance can be estimated during a zero divergence maneuver, i.e., around hover. The stability-based strategy is implemented and tested both in simulation and on board a Parrot AR drone 2.0. It is shown that the strategy can be used to: (1) trigger a final approach response during a constant divergence landing with fixed gain, (2) estimate the distance in hover, and (3) estimate distances during an entire landing if the robot uses adaptive gain control to continuously stay on the 'edge of oscillation.'

  3. Stability boundaries analysis of electric power system with DC transmission based on differential-algebraic equation system

    OpenAIRE

    Susuki, Yoshihiko; Hikihara Takashi; Chiang, HD

    2004-01-01

    This paper discusses stability boundaries in an electric power system with dc transmission based on a differential-algebraic equation (DAE) system. The DAE system is derived to analyze transient stability of the ac/dc power system: the differential equation represents the dynamics of the generator and the dc transmission, and the algebraic equation the active and reactive power relationship between the ac system and the dc transmission. In this paper complete characterization of stability bou...

  4. Lifetime prediction of EC, DPA, akardite II and MNA stabilized triple base propellants, comparison of heat generation rate and stabilizer consumption

    NARCIS (Netherlands)

    Boers, M.N.; Klerk, W.P.C. de

    2005-01-01

    A lifetime prediction study is carried out on four triple base propellant compositions by artificial ageing. The ageing effects are studied with High Performance Liquid Chromatography (HPLC) and Heat Flow Calorimetry (HFC) in order to find the most effective stabilizer and to evaluate the advantages

  5. A physiologically based model of orexinergic stabilization of sleep and wake.

    Directory of Open Access Journals (Sweden)

    Ben D Fulcher

    Full Text Available The orexinergic neurons of the lateral hypothalamus (Orx are essential for regulating sleep-wake dynamics, and their loss causes narcolepsy, a disorder characterized by severe instability of sleep and wake states. However, the mechanisms through which Orx stabilize sleep and wake are not well understood. In this work, an explanation of the stabilizing effects of Orx is presented using a quantitative model of important physiological connections between Orx and the sleep-wake switch. In addition to Orx and the sleep-wake switch, which is composed of mutually inhibitory wake-active monoaminergic neurons in brainstem and hypothalamus (MA and the sleep-active ventrolateral preoptic neurons of the hypothalamus (VLPO, the model also includes the circadian and homeostatic sleep drives. It is shown that Orx stabilizes prolonged waking episodes via its excitatory input to MA and by relaying a circadian input to MA, thus sustaining MA firing activity during the circadian day. During sleep, both Orx and MA are inhibited by the VLPO, and the subsequent reduction in Orx input to the MA indirectly stabilizes sustained sleep episodes. Simulating a loss of Orx, the model produces dynamics resembling narcolepsy, including frequent transitions between states, reduced waking arousal levels, and a normal daily amount of total sleep. The model predicts a change in sleep timing with differences in orexin levels, with higher orexin levels delaying the normal sleep episode, suggesting that individual differences in Orx signaling may contribute to chronotype. Dynamics resembling sleep inertia also emerge from the model as a gradual sleep-to-wake transition on a timescale that varies with that of Orx dynamics. The quantitative, physiologically based model developed in this work thus provides a new explanation of how Orx stabilizes prolonged episodes of sleep and wake, and makes a range of experimentally testable predictions, including a role for Orx in chronotype and

  6. A physiologically based model of orexinergic stabilization of sleep and wake.

    Science.gov (United States)

    Fulcher, Ben D; Phillips, Andrew J K; Postnova, Svetlana; Robinson, Peter A

    2014-01-01

    The orexinergic neurons of the lateral hypothalamus (Orx) are essential for regulating sleep-wake dynamics, and their loss causes narcolepsy, a disorder characterized by severe instability of sleep and wake states. However, the mechanisms through which Orx stabilize sleep and wake are not well understood. In this work, an explanation of the stabilizing effects of Orx is presented using a quantitative model of important physiological connections between Orx and the sleep-wake switch. In addition to Orx and the sleep-wake switch, which is composed of mutually inhibitory wake-active monoaminergic neurons in brainstem and hypothalamus (MA) and the sleep-active ventrolateral preoptic neurons of the hypothalamus (VLPO), the model also includes the circadian and homeostatic sleep drives. It is shown that Orx stabilizes prolonged waking episodes via its excitatory input to MA and by relaying a circadian input to MA, thus sustaining MA firing activity during the circadian day. During sleep, both Orx and MA are inhibited by the VLPO, and the subsequent reduction in Orx input to the MA indirectly stabilizes sustained sleep episodes. Simulating a loss of Orx, the model produces dynamics resembling narcolepsy, including frequent transitions between states, reduced waking arousal levels, and a normal daily amount of total sleep. The model predicts a change in sleep timing with differences in orexin levels, with higher orexin levels delaying the normal sleep episode, suggesting that individual differences in Orx signaling may contribute to chronotype. Dynamics resembling sleep inertia also emerge from the model as a gradual sleep-to-wake transition on a timescale that varies with that of Orx dynamics. The quantitative, physiologically based model developed in this work thus provides a new explanation of how Orx stabilizes prolonged episodes of sleep and wake, and makes a range of experimentally testable predictions, including a role for Orx in chronotype and sleep inertia.

  7. Method for stability analysis based on the Floquet theory and Vidyn calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ganander, Hans

    2005-03-01

    This report presents the activity 3.7 of the STEM-project Aerobig and deals with aeroelastic stability of the complete wind turbine structure at operation. As a consequence of the increase of sizes of wind turbines dynamic couplings are being more important for loads and dynamic properties. The steady ambition to increase the cost competitiveness of wind turbine energy by using optimisation methods lowers design margins, which in turn makes questions about stability of the turbines more important. The main objective of the project is to develop a general stability analysis tool, based on the VIDYN methodology regarding the turbine dynamic equations and the Floquet theory for the stability analysis. The reason for selecting the Floquet theory is that it is independent of number of blades, thus can be used for 2 as well as 3 bladed turbines. Although the latter ones are dominating on the market, the former has large potential when talking about offshore large turbines. The fact that cyclic and individual blade pitch controls are being developed as a mean for reduction of fatigue also speaks for general methods as Floquet. The first step of a general system for stability analysis has been developed, the code VIDSTAB. Together with other methods, as the snap shot method, the Coleman transformation and the use of Fourier series, eigenfrequences and modes can be analysed. It is general with no restrictions on the number of blades nor the symmetry of the rotor. The derivatives of the aerodynamic forces are calculated numerically in this first version. Later versions would include state space formulations of these forces. This would also be the case for the controllers of turbine rotation speed, yaw direction and pitch angle.

  8. Effect of 5.25 % sodium hypochlorite on color stability of acrylic and silicone based soft liners and a denture base acrylic resin.

    Science.gov (United States)

    Salloum, Alaa'a M

    2014-06-01

    The purpose of the current study was to investigate the effect of a chemical disinfectant (sodium hypochlorite 5.25 %) on color stability of a denture base acrylic resin and two processed soft denture lining materials of two different types (acrylic-based and silicone-based). Ten specimens from each type of materials tested were made (2 × 20 × 20 mm). All specimens were immersed in sodium hypochlorite (5.25 %). Colorimetric measurements for each specimen were taken before immersion, and after 24 h and 7 days of immersion. Color changes were evaluated using the CIE L*a*b* colorimetric system. Data were statistically analyzed with one-way analysis of variance (ANOVA) (α = 0.05). ANOVA was followed by Bonferroni test to determine which groups differed from each other. ΔE and ΔL* of the silicone-based liner at the 1st and 7th days of immersion were significantly more than of denture base acrylic resin and acrylic-based liner. Change in ΔL* values of denture base acrylic resin and acrylic-based liner was small and statistically insignificant after 24 h of its immersion. However, the increase in ΔL* values of the acrylic-based liner after 7 days of immersion was considerably more than of denture base acrylic resin. Color changes in denture base acrylic resin and soft denture liners tended to increase with longer immersion times, and the color stability of the soft denture liners was influenced by its chemical type.

  9. Dispersion stability and thermophysical properties of environmentally friendly graphite oil–based nanofluids used in machining

    Directory of Open Access Journals (Sweden)

    Yu Su

    2016-01-01

    Full Text Available As environmentally friendly cutting fluids, vegetable-based oil and ester oil are being more and more widely used in metal cutting industry. However, their cooling and lubricating properties are required to be further improved in order to meet more cooling and lubricating challenges in high-efficiency machining. Nanofluids with enhanced heat carrying and lubricating capabilities seem to give a promising solution. In this article, graphite oil–based nanofluids with LB2000 vegetable-based oil and PriEco6000 unsaturated polyol ester as base fluids were prepared by ultrasonically assisted two-step method, and their dispersion stability and thermophysical properties such as viscosity and thermal conductivity were experimentally and theoretically investigated at different ultrasonication times. The results indicate that graphite-PriEco6000 nanofluid showed better dispersion stability, higher viscosity, and thermal conductivity than graphite-LB2000 nanofluid, which made it more suitable for application in high-efficiency machining as coolant and lubricant. The theoretical classical models showed good agreement with the thermal conductivity values of graphite oil–based nanofluids measured experimentally. However, the deviation between the experimental values of viscosity and the theoretical models was relatively big. New empirical correlations were proposed for predicting the viscosity of graphite oil–based nanofluids at various ultrasonication times.

  10. Global exponential stability of neural networks with time-varying delay based on free-matrix-based integral inequality.

    Science.gov (United States)

    He, Yong; Ji, Meng-Di; Zhang, Chuan-Ke; Wu, Min

    2016-05-01

    This paper is concerned with global exponential stability problem for a class of neural networks with time-varying delays. Using a new proposed inequality called free-matrix-based integral inequality, a less conservative criterion is proposed, which is expressed by linear matrix inequalities. Two numerical examples are given to show the effectiveness and superiority of the obtained criterion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Sensitivity analysis and calibration of a dynamic physically based slope stability model

    Science.gov (United States)

    Zieher, Thomas; Rutzinger, Martin; Schneider-Muntau, Barbara; Perzl, Frank; Leidinger, David; Formayer, Herbert; Geitner, Clemens

    2017-06-01

    Physically based modelling of slope stability on a catchment scale is still a challenging task. When applying a physically based model on such a scale (1 : 10 000 to 1 : 50 000), parameters with a high impact on the model result should be calibrated to account for (i) the spatial variability of parameter values, (ii) shortcomings of the selected model, (iii) uncertainties of laboratory tests and field measurements or (iv) parameters that cannot be derived experimentally or measured in the field (e.g. calibration constants). While systematic parameter calibration is a common task in hydrological modelling, this is rarely done using physically based slope stability models. In the present study a dynamic, physically based, coupled hydrological-geomechanical slope stability model is calibrated based on a limited number of laboratory tests and a detailed multitemporal shallow landslide inventory covering two landslide-triggering rainfall events in the Laternser valley, Vorarlberg (Austria). Sensitive parameters are identified based on a local one-at-a-time sensitivity analysis. These parameters (hydraulic conductivity, specific storage, angle of internal friction for effective stress, cohesion for effective stress) are systematically sampled and calibrated for a landslide-triggering rainfall event in August 2005. The identified model ensemble, including 25 behavioural model runs with the highest portion of correctly predicted landslides and non-landslides, is then validated with another landslide-triggering rainfall event in May 1999. The identified model ensemble correctly predicts the location and the supposed triggering timing of 73.0 % of the observed landslides triggered in August 2005 and 91.5 % of the observed landslides triggered in May 1999. Results of the model ensemble driven with raised precipitation input reveal a slight increase in areas potentially affected by slope failure. At the same time, the peak run-off increases more markedly, suggesting that

  12. Process for stabilizing dimensions of duplex stainless steels for service at elevated temperatures

    Science.gov (United States)

    Hull, Frederick C.; Tobin, John C.

    1981-01-01

    Duplex stainless steel materials containing austenite plus delta ferrite, are dimensionally stabilized by heating the material to a reaction temperature between about 1050.degree.-1450.degree. F. (566.degree.-788.degree. C.), holding it at this temperature during transformation of delta ferrite to austenite plus sigma phase, and subsequently heating to a reversion temperature between about 1625.degree.-1750.degree. F. (885.degree.-954.degree. C.), whereby the sigma phase transforms back to ferrite, but the austenite remains dispersed in the ferrite phase. Final controlled cooling permits transformation of ferrite to austenite plus sigma and, later, precipitation of carbides.

  13. A Note on "Stability of Tâtonnement Processes of Short Period Equilibria with Rational Expectations"

    NARCIS (Netherlands)

    Herings, P.J.J.

    1997-01-01

    In Hens (1997), a new adjustment process is proposed for a setting with reopening spot and asset markets. He argues by means of an intemporal variant of Scarf's example that this process is more stable than the other processes, although in general it might be more stable or less stable. This note

  14. Systematic screening methodology and energy efficient design of ionic liquid-based separation processes

    DEFF Research Database (Denmark)

    Kulajanpeng, Kusuma; Suriyapraphadilok, Uthaiporn; Gani, Rafiqul

    2016-01-01

    A systematic methodology for the screening of ionic liquids (ILs) as entrainers and for the design of ILs-based separation processes in various homogeneous binary azeotropic mixtures has been developed. The methodology focuses on the homogeneous binary aqueous azeotropic systems (for example, water...... based on a combination of criteria such as stability, toxicity, and their environmental impacts. All best ILs were used as entrainers, and an extractive distillation column (EDC) and ionic liquid recovery column were designed and simulated with a process simulator to determine the overall energy...

  15. Mechanisms of improving the cyclic stability of V-Ti-based hydrogen storage electrode alloys

    International Nuclear Information System (INIS)

    Miao He; Wang Weiguo

    2010-01-01

    Research highlights: → The corrosion resistance of V-based phase is much lower than that of C14 Laves phase of V-Ti-based alloys. → The addition of Cr which mostly distributes in V-based phase can effectively increase the anti-corrosion ability of V-Ti-based alloys. → The addition of Cr which mostly distributes in V-based phase can effectively increase the anti-corrosion ability of V-Ti-based alloys. - Abstract: In this work, the mechanisms of improving the cyclic stability of V-Ti-based hydrogen storage electrode alloys were investigated systemically. Several key factors for example corrosion resistance, pulverization resistance and oxidation resistance were evaluated individually. The V-based solid solution phase has much lower anti-corrosion ability than C14 Laves phase in KOH solution, and the addition of Cr in V-Ti-based alloys can suppress the dissolution of the main hydrogen absorption elements of the V-based phase in the alkaline solution. During the charge/discharge cycling, the alloy particles crack or break into several pieces, which accelerates their corrosion/oxidation and increases the contact resistance of the alloy electrodes. Proper decreasing the Vickers hardness and enhancing the fracture toughness can increase the pulverization resistance of the alloy particles. The oxidation layer thickness on the alloy particle surface obviously increases during charge/discharge cycling. This deteriorates their electro-catalyst activation to the electrochemical reaction, and leads to a quick degradation. Therefore, enhancing the oxide resistance can obviously improve the cyclic stability of V-Ti-based hydrogen storage electrode alloys.

  16. Using multi-scale stable isotopes analyses to study the microbial processes of soil organic matter stabilization

    Science.gov (United States)

    Hatton, P.; Remusat, L.; Zeller, B.; Bode, S.; Brewer, E.; Boeckx, P. F.; Derrien, D.

    2012-12-01

    stabilization efficiency for the microorganisms found in there and/ or the transfer of the microbial biomasses from plant debris to microbial aggregates, likely along with the transfers of decaying litter residues. Combining several complementary stable isotope approaches, we showed that microbial products are stabilized (i) directly through immobilization within the microbial biomass and (ii) indirectly through an abundant production of extracellular microbial products. We also demonstrated that such combination techniques does not only suits for the study of fine-scale processes, but also provide new insights on the ecology of microbial processes in an environment as complex as soil.

  17. Effect of preheat repetition on color stability of methacrylate- and silorane-based composite resins

    OpenAIRE

    Abed Kahnamouei, Mehdi; Gholizadeh, Sarah; Rikhtegaran, Sahand; Daneshpooy, Mehdi; Kimyai, Soodabeh; Alizadeh Oskoee, Parnian; Rezaei, Yashar

    2017-01-01

    Background. The aim of this study was to investigate the effect of preheating methacrylate- and silorane-based composite resins on their color stability up to 40 times at 55‒60°C. Methods. Seventy-six methacrylate and silorane-based composite resin samples, with a diameter of 10 mm and a height of 2 mm, were divided into 4 groups (n=19). After the samples were prepared, their color parameters were determined using a reflective spectrophotometer. The composite resin samples were separately sto...

  18. The potential applications in heavy oil EOR with the nanoparticle and surfactant stabilized solvent-based emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, F. [Texas A and M Univ., College Station, TX (United States)

    2010-07-01

    The main challenges in developing the heavy oil reservoirs in the Alaska North Slope (ANS) include technical challenges regarding thermal recovery; sand control and disposal; high asphaltene content; and low in-situ permeability. A chemical enhanced oil recovery method may be possible for these reservoirs. Solvent based emulsion flooding provides mobility control; oil viscosity reduction; and in-situ emulsification of heavy oil. This study evaluated the potential application of nano-particle-stabilized solvent based emulsion injection to enhance heavy oil recovery in the ANS. The optimized micro-emulsion composition was determined using laboratory tests such as phase behaviour scanning, rheology studies and interfacial tension measurements. The optimized nano-emulsions were used in core flooding experiments to verify the recovery efficiency. The study revealed that the potential use of this kind of emulsion flooding is a promising enhanced oil recovery process for some heavy oil reservoirs in Alaska, Canada and Venezuela. 4 refs., 2 tabs., 10 figs.

  19. Development of a hardware-based AC microgrid for AC stability assessment

    Science.gov (United States)

    Swanson, Robert R.

    As more power electronic-based devices enable the development of high-bandwidth AC microgrids, the topic of microgrid power distribution stability has become of increased interest. Recently, researchers have proposed a relatively straightforward method to assess the stability of AC systems based upon the time-constants of sources, the net bus capacitance, and the rate limits of sources. In this research, a focus has been to develop a hardware test system to evaluate AC system stability. As a first step, a time domain model of a two converter microgrid was established in which a three phase inverter acts as a power source and an active rectifier serves as an adjustable constant power AC load. The constant power load can be utilized to create rapid power flow transients to the generating system. As a second step, the inverter and active rectifier were designed using a Smart Power Module IGBT for switching and an embedded microcontroller as a processor for algorithm implementation. The inverter and active rectifier were designed to operate simultaneously using a synchronization signal to ensure each respective local controller operates in a common reference frame. Finally, the physical system was created and initial testing performed to validate the hardware functionality as a variable amplitude and variable frequency AC system.

  20. Virtual velocity loop based on MEMS accelerometers for optical stabilization control system

    Science.gov (United States)

    Ren, Wei; Deng, Chao; Mao, Yao; Ren, Ge

    2017-08-01

    In the optical stabilization control system (OSCS) control system based on a charge-coupled device (CCD), stabilization performance of the line-of-sight is severely limited by the mechanical resonance and the low sampling rate of the CCD. An approach to improve the stabilization performance of the OSCS control system with load restriction based on three loops, including an acceleration loop, a virtual velocity loop, and a position loop, by using MEMS accelerometers and a CCD is proposed. The velocity signal is obtained by accelerators instead of gyro sensors. Its advantages are low power, low cost, small size, and wide measuring range. A detailed analysis is provided to show how to design the virtual velocity loop and correct virtual velocity loop drift. Experimental results show that the proposed multiloop feedback control method with virtual velocity loop in which the disturbance suppression performance is better than that of the dual loop control with only an acceleration loop and a position loop at low frequency.

  1. Stability Analysis of a Voltage-Based Controller for Robot Manipulators

    Directory of Open Access Journals (Sweden)

    Jorge Orrante-Sakanassi

    2013-01-01

    Full Text Available A voltage-based control scheme for robot manipulators has been presented in recent literature, where feedback linearization is applied in the electrical equations of the DC motors in order to cancel the electrical current terms. However, in this paper we show that this control technique generates a system of the form Ex = Ax + Bu, where E is a singular matrix, that is to say, a generalized state-space system or singular system. This paper introduces a formal stability analysis of the respective system by considering the state-space equation as a singular system. Furthermore, in order to avoid the singularity of the closed-loop system, modified voltage-based control schemes are proposed, whose Lyapunov stability analyses conclude semiglobal asymptotic stability for the set-point control case and uniform boundedness of the solutions and semiglobal convergence of the position, as well as velocity errors for the tracking control case. The proposed control systems are simulated for the tracking and set-point cases using the CICESE Pelican robot driven by DC motors.

  2. Extraction and stability of bovine serum albumin (BSA) using cholinium-based Good's buffers ionic liquids.

    Science.gov (United States)

    Taha, Mohamed; Quental, Maria V; Correia, Isabel; Freire, Mara G; Coutinho, João A P

    2015-07-01

    Good's buffers ionic liquids (GB-ILs), composed of cholinium-based cations and Good's buffers anions, display self-buffering characteristics in the biological pH range, and their polarity and hydrophobicity can be easily tuned by a proper manipulation of their ions chemical structures. In this work, the extraction ability for bovine serum albumin (BSA) of aqueous biphasic systems (ABS) formed by polypropylene glycol 400 (PPG 400) and several GB-ILs was evaluated. ABS formed by PPG 400 and cholinium chloride ([Ch]Cl), GBs, and sucrose were also investigated for comparison purposes. It is shown that BSA preferentially migrates for the GB-IL-rich phase, with extraction efficiencies of 100%, achieved in a single-step. Dynamic light scattering, and circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopies were employed to evaluate the effect of the investigated cholinium-based GB-ILs on the BSA stability, and compared with results obtained for the respective GBs precursors, [Ch]Cl and sucrose, a well-known protein stabilizer. Molecular docking studies were also carried out to investigate on the binding sites of GB-IL ions to BSA. The experimental results confirm that BSA has a higher stability in GB-ILs than in any of the other compounds investigated.

  3. Stability and Activity of Non-Noble-Metal-Based Catalysts Toward the Hydrogen Evolution Reaction.

    Science.gov (United States)

    Ledendecker, Marc; Mondschein, Jared S; Kasian, Olga; Geiger, Simon; Göhl, Daniel; Schalenbach, Max; Zeradjanin, Aleksandar; Cherevko, Serhiy; Schaak, Raymond E; Mayrhofer, Karl

    2017-08-07

    A fundamental understanding of the behavior of non-noble based materials toward the hydrogen evolution reaction is crucial for the successful implementation into practical devices. Through the implementation of a highly sensitive inductively coupled plasma mass spectrometer coupled to a scanning flow cell, the activity and stability of non-noble electrocatalysts is presented. The studied catalysts comprise a range of compositions, including metal carbides (WC), sulfides (MoS 2 ), phosphides (Ni 5 P 4 , Co 2 P), and their base metals (W, Ni, Mo, Co); their activity, stability, and degradation behavior was elaborated and compared to the state-of-the-art catalyst platinum. The non-noble materials are stable at HER potentials but dissolve substantially when no current is flowing. Through pre- and post-characterization of the catalysts, explanations of their stability (thermodynamics and kinetics) are discussed, challenges for the application in real devices are analyzed, and strategies for circumventing dissolution are suggested. The precise correlation of metal dissolution with applied potential/current density allows for narrowing down suitable material choices as replacement for precious group metals as for example, platinum and opens up new ways in finding cost-efficient, active, and stable new-generation electrocatalysts. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Process-Based Thinking in Ecosystem Education

    Science.gov (United States)

    Jordan, Rebecca C.; Gray, Steven A.; Brooks, Wesley R.; Honwad, Sameer; Hmelo-Silver, Cindy E.

    2013-01-01

    Understanding complex systems such as ecosystems is difficult for young K-12 students, and students' representations of ecosystems are often limited to nebulously defined relationships between macro-level structural components inherent to the ecosystem in focus (rainforest, desert, pond, etc.) instead of generalizing processes across ecosystems…

  5. Model based optimization of MSWC process control

    NARCIS (Netherlands)

    Kessel, L.B.M. van; Leskens, M.

    2002-01-01

    Optimization of municipal solid waste combustion (MSWC), processes is an im portant issue doe to the ever-lasting need for emission reduction. more optimal use of raw materials and overall cost reduction. The key of the approach of TNO (Netherlands Orgaru sation for Applied Scientific Research) to

  6. Biotechnology based processes for arsenic removal

    NARCIS (Netherlands)

    Huisman, J.; Olde Weghuis, M.; Gonzalez-Contreras, P.A.

    2011-01-01

    The regulations for arsenic control have become strict. Therefore, better technologies to remove arsenic from bleeds and effluents are desired. In addition, no single solution is suitable for all cases. The properties of the process streams and the storage facilities are major factors determining

  7. Bipartite entangled stabilizer mutually unbiased bases as maximum cliques of Cayley graphs

    Energy Technology Data Exchange (ETDEWEB)

    Dam, Wim van; Howard, Mark [Department of Computer Science, University of California, Santa Barbara, California 93106, USA and (United States); Department of Physics, University of California, Santa Barbara, California 93106 (United States); Department of Physics, University of California, Santa Barbara, California 93106 (United States)

    2011-07-15

    We examine the existence and structure of particular sets of mutually unbiased bases (MUBs) in bipartite qudit systems. In contrast to well-known power-of-prime MUB constructions, we restrict ourselves to using maximally entangled stabilizer states as MUB vectors. Consequently, these bipartite entangled stabilizer MUBs (BES MUBs) provide no local information, but are sufficient and minimal for decomposing a wide variety of interesting operators including (mixtures of) Jamiolkowski states, entanglement witnesses, and more. The problem of finding such BES MUBs can be mapped, in a natural way, to that of finding maximum cliques in a family of Cayley graphs. Some relationships with known power-of-prime MUB constructions are discussed, and observables for BES MUBs are given explicitly in terms of Pauli operators.

  8. Stability analysis and active damping for LLCL-filter based grid-connected inverters

    DEFF Research Database (Denmark)

    Huang, Min; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    A higher order passive power filter (LLCL-filter) for the grid-tied inverter is becoming attractive for the industrial applications due to the possibility to reduce the cost of the copper and the magnetic material. To avoid the well-known stability problems of the LLCL-filter it is requested to use...... either passive or active damping methods. This paper analyzes the stability when damping is required and when damping is not necessary considering sampling and transport delay. Basic LLCL resonance damping properties of different feedback states are also studied. Then an active damping method which...... is using the capacitor current feedback for LLCL-filter is introduced. Based on this method, a design procedure for the control method is given. Last, both simulation and experimental results are provided to validate the theoretical analysis of this paper....

  9. Stability of memories of parental rearing among psychiatric inpatients: a replication based on EMBU subscales.

    Science.gov (United States)

    Richter, J; Eisemann, M

    2001-01-01

    With regard to information about parental rearing, retrospective data are exclusively available among adults. These data are vulnerable due to various biases. This study was performed in order to replicate the findings of overall stability of three perceived parental rearing factors of the EMBU (Swedish acronym for 'own memories of childhood upbringing') based on 14 rather detailed subscales. A consecutive sample of 220 depressive inpatients were investigated on admission and at discharge by means of the EMBU, the Beck Depression Inventory and the Dysfunctional Attitude Scale. Perceived parental rearing scores showed high stability despite clinically significant changes in the severity of depression, except for 'tolerance', 'guilt engendering', 'performance orientation' and 'shaming' parenting with probable gender-specific effects which were found to covary with dysfunctional attitudes. Recall of parenting should be taken as a subjective truth when it is assessed by standardised behaviour-oriented questionnaires like the EMBU. Copyright 2002 S. Karger AG, Basel

  10. Lyapunov-based Stability of Feedback Interconnections of Negative Imaginary Systems

    KAUST Repository

    Ghallab, Ahmed G.

    2017-10-19

    Feedback control systems using sensors and actuators such as piezoelectric sensors and actuators, micro-electro-mechanical systems (MEMS) sensors and opto-mechanical sensors, are allowing new advances in designing such high precision technologies. The negative imaginary control systems framework allows for robust control design for such high precision systems in the face of uncertainties due to unmodelled dynamics. The stability of the feedback interconnection of negative imaginary systems has been well established in the literature. However, the proofs of stability feedback interconnection which are used in some previous papers have a shortcoming due to a matrix inevitability issue. In this paper, we provide a new and correct Lyapunov-based proof of one such result and show that the result is still true.

  11. Comparing and Combining Measurement-Based and Driven-Dissipative Entanglement Stabilization*

    Directory of Open Access Journals (Sweden)

    Y. Liu

    2016-03-01

    Full Text Available We demonstrate and contrast two approaches to the stabilization of qubit entanglement by feedback. Our demonstration is built on a feedback platform consisting of two superconducting qubits coupled to a cavity, which are measured by a nearly quantum-limited measurement chain and controlled by high-speed classical logic circuits. This platform is used to stabilize entanglement by two nominally distinct schemes: a “passive” reservoir engineering method and an “active” correction based on conditional parity measurements. In view of the instrumental roles that these two feedback paradigms play in quantum error correction and quantum control, we directly compare them on the same experimental setup. Furthermore, we show that a second layer of feedback can be added to each of these schemes, which heralds the presence of a high-fidelity entangled state in real time. This “nested” feedback brings about a marked entanglement fidelity improvement without sacrificing success probability.

  12. A general framework for global asymptotic stability analysis of delayed neural networks based on LMI approach

    International Nuclear Information System (INIS)

    Cao Jinde; Ho, Daniel W.C.

    2005-01-01

    In this paper, global asymptotic stability is discussed for neural networks with time-varying delay. Several new criteria in matrix inequality form are given to ascertain the uniqueness and global asymptotic stability of equilibrium point for neural networks with time-varying delay based on Lyapunov method and Linear Matrix Inequality (LMI) technique. The proposed LMI approach has the advantage of considering the difference of neuronal excitatory and inhibitory efforts, which is also computationally efficient as it can be solved numerically using recently developed interior-point algorithm. In addition, the proposed results generalize and improve previous works. The obtained criteria also combine two existing conditions into one generalized condition in matrix form. An illustrative example is also given to demonstrate the effectiveness of the proposed results

  13. Stability Evaluation on Surrounding Rocks of Underground Powerhouse Based on Microseismic Monitoring

    Directory of Open Access Journals (Sweden)

    Feng Dai

    2015-01-01

    Full Text Available To study the stability of underground powerhouse at Houziyan hydropower station during excavation, a microseismic monitoring system is adopted. Based on the space-time distribution characteristics of microseismic events during excavation of the main powerhouse, the correlation between microseismic events and blasting construction is established; and the microseismic clustering areas of the underground powerhouse are identified and delineated. The FLAC3D code is used to simulate the deformation of main powerhouse. The simulated deformation characteristics are consistent with that recorded by microseismic monitoring. Finally, the correlation between the macroscopic deformation of surrounding rock mass and microseismic activities is also revealed. The results show that multiple faults between 1# and 3# bus tunnels are activated during excavation of floors V and VI of the main powerhouse. The comprehensive method combining microseismic monitoring with numerical simulation as well as routine monitoring can provide an effective way to evaluate the surrounding rock mass stability of underground caverns.

  14. Quality stability and sensory attributes of apple juice processed by thermosonication, pulsed electric field and thermal processing.

    Science.gov (United States)

    Sulaiman, Alifdalino; Farid, Mohammed; Silva, Filipa Vm

    2017-04-01

    Worldwide, apple juice is the second most popular juice, after orange juice. It is susceptible to enzymatic browning spoilage by polyphenoloxidase, an endogenous enzyme. In this study, Royal Gala apple juice was treated by thermosonication (TS: 1.3 W/mL, 58 ℃, 10 min), pulsed electric field (PEF: 24.8 kV/cm, 60 pulses, 169 µs treatment time, 53.8 ℃) and heat (75 ℃, 20 min) and stored at 3.0 ℃ and 20.0 ℃ for 30 days. A sensory analysis was carried out after processing. The polyphenoloxidase activity, antioxidant activity and total color difference of the apple juice were determined before and after processing and during storage. The sensory analysis revealed that thermosonication and pulsed electric field juices tasted differently from the thermally treated juice. Apart from the pulsed electric field apple juice stored at room temperature, the processed juice was stable during storage, since the pH and soluble solids remained constant and fermentation was not observed. Polyphenoloxidase did not reactivate during storage. Along storage, the juices' antioxidant activity decreased and total color difference increased (up to 6.8). While the antioxidant activity increased from 86 to 103% with thermosonication and was retained after pulsed electric field, thermal processing reduced it to 67%. The processing increased the total color difference slightly. No differences in the total color difference of the juices processed by the three methods were registered after storage. Thermosonication and pulsed electric field could possibly be a better alternative to thermal preservation of apple juice, but refrigerated storage is recommended for pulsed electric field apple juice.

  15. Micropredation on sea urchins as a potential stabilizing process for rocky reefs

    Science.gov (United States)

    Bonaviri, Chiara; Gianguzza, Paola; Pipitone, Carlo; Hereu, Bernat

    2012-10-01

    Rocky reefs can shift from forest, a state dominated by erect algae with high biodiversity, to barren, an impoverished state dominated by encrusting algae. Sea urchins, abundant in barrens, are usually held responsible for the maintenance of this state. Predation by large fish can revert the barren state to forest by controlling sea urchin populations. However, the persistence of a community state sometimes seems to be independent from the presence of such large predators, suggesting the existence of other unknown mechanisms ensuring their stability. Theoretical studies suggest that the settler stage of sea urchins is determinant for maintaining a given rocky reef state. In this study, we have identified several potential invertebrate micropredators of settlers of the sea urchin Paracentrotus lividus and measured their predation activity. Predation rates showed marked differences among species, possibly due to morphological and/or behavioral traits. Micropredators were more abundant in the forest than in barren, and their potential impact on the sea urchin community differed between the two states by two orders of magnitude. These findings suggest a novel self-perpetuating mechanism stabilizing rocky reef systems, where the abundance of micropredators may contribute to shape the sea urchin population, which in turn is responsible for the persistence of the state.

  16. Quantification and analysis of color stability based on thermal transient behavior in white LED lamps.

    Science.gov (United States)

    Nisa Khan, M

    2017-09-20

    We present measurement and analysis of color stability over time for two categories of white LED lamps based on their thermal management scheme, which also affects their transient lumen depreciation. We previously reported that lumen depreciation in LED lamps can be minimized by properly designing the heat sink configuration that allows lamps to reach a thermal equilibrium condition quickly. Although it is well known that lumen depreciation degrades color stability of white light since color coordinates vary with total lumen power by definition, quantification and characterization of color shifts based on thermal transient behavior have not been previously reported in literature for LED lamps. Here we provide experimental data and analysis of transient color shifts for two categories of household LED lamps (from a total of six lamps in two categories) and demonstrate that reaching thermal equilibrium more quickly provides better stability for color rendering, color temperature, and less deviation of color coordinates from the Planckian blackbody locus line, which are all very important characterization parameters of color for white light. We report for the first time that a lamp's color degradation from the turn-on time primarily depends on thermal transient behavior of the semiconductor LED chip, which experiences a wavelength shift as well as a decrease in its dominant wavelength peak value with time, which in turn degrades the phosphor conversion. For the first time, we also provide a comprehensive quantitative analysis that differentiates color degradation due to the heat rise in GaN/GaInN LED chips and subsequently the boards these chips are mounted on-from that caused by phosphor heating in a white LED module. Finally, we briefly discuss why there are some inevitable trade-offs between omnidirectionality and color and luminous output stability in current household LED lamps and what will help eliminate these trade-offs in future lamp designs.

  17. Analysis method of beam pointing stability based on optical transmission matrix

    Science.gov (United States)

    Wang, Chuanchuan; Huang, PingXian; Li, Xiaotong; Cen, Zhaofen

    2016-10-01

    Quite a lot of factors will make effects on beam pointing stability of an optical system, Among them, the element tolerance is one of the most important and common factors. In some large laser systems, it will make final micro beams spot on the image plane deviate obviously. So it is essential for us to achieve effective and accurate analysis theoretically on element tolerance. In order to make the analysis of beam pointing stability convenient and theoretical, we consider transmission of a single chief ray rather than beams approximately to stand for the whole spot deviation. According to optical matrix, we also simplify this complex process of light transmission to multiplication of many matrices. So that we can set up element tolerance model, namely having mathematical expression to illustrate spot deviation in an optical system with element tolerance. In this way, we can realize quantitative analysis of beam pointing stability theoretically. In second half of the paper, we design an experiment to get the spot deviation in a multipass optical system caused by element tolerance, then we adjust the tolerance step by step and compare the results with the datum got from tolerance model, finally prove the correction of tolerance model successfully.

  18. Stochastic stability of mechanical systems under renewal jump process parametric excitation

    DEFF Research Database (Denmark)

    Iwankiewicz, R.; Nielsen, Søren R.K.; Larsen, Jesper Winther

    2005-01-01

    independent, negative exponential distributed variables; hence, the arrival process may be termed as a generalized Erlang renewal process. The excitation process is governed by the stochastic equation driven by two independent Poisson processes, with different parameters. If the response in a single mode...... is investigated, the problem is governed in the state space by two stochastic equations, because the stochastic equation for the excitation process is autonomic. However due to the parametric nature of the excitation, the nonlinear term appears at the right-hand sides of the equations. The equations become linear...... of the stochastic equation governing the natural logarithm of the hyperspherical amplitude process and using the modification of the method wherein the time averaging of the pertinent expressions is replaced by ensemble averaging. It is found that the direct simulation is more suitable and that the asymptotic mean...

  19. Stability of silver nanowire based electrodes under environmental and electrical stresses

    Science.gov (United States)

    Mayousse, Céline; Celle, Caroline; Fraczkiewicz, Alexandra; Simonato, Jean-Pierre

    2015-01-01

    Flexible transparent electrodes fabricated with random networks of silver nanowires (AgNWs) have been widely studied in recent years. This approach appears to be a promising alternative to replace ITO (indium tin oxide) in many optoelectronic applications. Many successful integrations in functional devices have already evidenced the high potential of this technology, but unfortunately only very few studies have been dedicated so far to the stability of this material. We present here a study dealing with the alteration of the electrical properties of AgNW meshes when subjected to different stresses. We demonstrate that AgNW electrodes are very stable when stored under ambient atmosphere up to, at least, two and a half years. Accelerated ageing processes also reveal that concentrated H2S or exposure to light does not cause any significant sheet resistance modification. However, the combination of high relative humidity and high temperature seems to be more critical. In addition, long lasting contact (two years) with PEDOT:PSS can induce deterioration of the electrical properties. Similarly, AgNW/PEDOT:PSS hybrid materials exhibit weaker stability under electrical stress when compared to pristine AgNW networks.Flexible transparent electrodes fabricated with random networks of silver nanowires (AgNWs) have been widely studied in recent years. This approach appears to be a promising alternative to replace ITO (indium tin oxide) in many optoelectronic applications. Many successful integrations in functional devices have already evidenced the high potential of this technology, but unfortunately only very few studies have been dedicated so far to the stability of this material. We present here a study dealing with the alteration of the electrical properties of AgNW meshes when subjected to different stresses. We demonstrate that AgNW electrodes are very stable when stored under ambient atmosphere up to, at least, two and a half years. Accelerated ageing processes also

  20. Link between structural and mechanical stability of fcc- and bcc-based ordered MgeLi alloys

    CSIR Research Space (South Africa)

    Phasha, MJ

    2010-06-01

    Full Text Available properties of cubic-based MgeLi alloys. The heats of formation and elastic moduli were used in predicting structural stability profile, and their results are consistent with each other. In terms of phase stability, an interesting correlation between...