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Sample records for photophysical control mechanism

  1. A photophysical control mechanism for zeaxanthin-associated radiationless energy dissipation in photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Frank, H.A.; Cua, A. [Connecticut Univ., Storrs, CT (United States). Dept. of Chemistry; Young, A. [Johns Moores Univ., Liverpool (United Kingdom). School of Biological and Earth Sciences; Gosztola, D.; Wasielewski, M.R. [Argonne National Lab., IL (United States)

    1994-09-01

    Understanding the way in which excess solar energy is dissipated by photosynthetic membranes under high light stress is a major problem in photosynthesis studies. This paper reports femtosecond time-resolved, fast-transient optical spectroscopic analyses of three important xanthophylls: violaxanthin, antheraxanthin, zeoaxanthin. The results support the notion that the enzymatic reactions that interconvert these xanthophylls act as a kind of ``molecular gear shift`` controlling whether the molecules function as light-harvesting pigments performing forward energy transfer or as fluorescence quenchers performing reverse energy transfer.

  2. Photophysical properties and energy transfer mechanism of PFO/Fluorol 7GA hybrid thin films

    Energy Technology Data Exchange (ETDEWEB)

    Al-Asbahi, Bandar Ali, E-mail: alasbahibandar@gmail.com [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Department of Physics, Faculty of Science, Sana' a University (Yemen); Jumali, Mohammad Hafizuddin Haji, E-mail: hafizhj@ukm.my [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Yap, Chi Chin; Flaifel, Moayad Husein [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Salleh, Muhamad Mat [Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

    2013-10-15

    Photophysical properties of poly (9,9′-di-n-octylfluorenyl-2.7-diyl) (PFO)/2-butyl-6- (butylamino)benzo [de] isoquinoline-1,3-dione (Fluorol 7GA) and energy transfer between them have been investigated. In this work, both PFO and Fluorol 7GA act as donor and acceptor, respectively. Based on the absorption and luminescence measurements, the photophysical and energy transfer properties such as fluorescence quantum yield (Φ{sub f}), fluorescence lifetime (τ), radiative rate constant (k{sub r}), non-radiative rate constant (k{sub nr}), quenching rate constant (k{sub SV}), energy transfer rate constant (k{sub ET}), energy transfer probability (P{sub DA}), energy transfer efficiency (η), critical concentration of acceptor (C{sub o}), energy transfer time (τ{sub ET}) and critical distance of energy transfer (R{sub o}) were calculated. Large values of k{sub SV}, k{sub ET} and R{sub o} suggested that Förster-type energy transfer was the dominant mechanism for the energy transfer between the excited donor and ground state acceptor molecules. It was observed that the Förster energy transfer together with the trapping process are crucial for performance improvement in ITO/(PFO/Fluorol7GA)/Al device. -- Highlights: • The efficient of energy transfer from PFO to Fluorol 7GA was evidenced. • The resonance energy transfer (Förster type) is the dominant mechanism. • Hsu et al. model was used to calculate Φ{sub f}, τ, k{sub r} and k{sub nr} of PFO thin film. • Several of the photophysical and energy transfer properties were calculated. • Trapping process and Förster energy transfer led to improve the device performance.

  3. Photophysics and Photochemistry of Canonical Nucleobases’ Thioanalogs: From Quantum Mechanical Studies to Time Resolved Experiments

    Directory of Open Access Journals (Sweden)

    Serra Arslancan

    2017-06-01

    Full Text Available Interest in understanding the photophysics and photochemistry of thiated nucleobases has been awakened because of their possible involvement in primordial RNA or their potential use as photosensitizers in medicinal chemistry. The interpretation of the photodynamics of these systems, conditioned by their intricate potential energy surfaces, requires the powerful interplay between experimental measurements and state of the art molecular simulations. In this review, we provide an overview on the photophysics of natural nucleobases’ thioanalogs, which covers the last 30 years and both experimental and computational contributions. For all the canonical nucleobase’s thioanalogs, we have compiled the main steady state absorption and emission features and their interpretation in terms of theoretical calculations. Then, we revise the main topographical features, including stationary points and interstate crossings, of their potential energy surfaces based on quantum mechanical calculations and we conclude, by combining the outcome of different spectroscopic techniques and molecular dynamics simulations, with the mechanism by which these nucleobase analogs populate their triplet excited states, which are at the origin of their photosensitizing properties.

  4. Controlling photophysical properties of ultrasmall conjugated polymer nanoparticles through polymer chain packing

    KAUST Repository

    Piwonski, Hubert Marek

    2017-05-16

    Applications of conjugated polymer nanoparticles (Pdots) for imaging and sensing depend on their size, fluorescence brightness and intraparticle energy transfer. The molecular design of conjugated polymers (CPs) has been the main focus of the development of Pdots. Here we demonstrate that proper control of the physical interactions between the chains is as critical as the molecular design. The unique design of twisted CPs and fine-tuning of the reprecipitation conditions allow us to fabricate ultrasmall (3.0–4.5 nm) Pdots with excellent photostability. Extensive photophysical and structural characterization reveals the essential role played by the packing of the polymer chains in the particles in the intraparticle spatial alignment of the emitting sites, which regulate the fluorescence brightness and the intraparticle energy migration efficiency. Our findings enhance understanding of the relationship between chain interactions and the photophysical properties of CP nanomaterials, providing a framework for designing and fabricating functional Pdots for imaging applications.

  5. Pathways and Mechanisms Underlying the Photophysics and Photochemistry of Riboflavin induced cornea crosslinking

    DEFF Research Database (Denmark)

    Breitenbach, Thomas; Ogilby, Peter Remsen

    In this talk, we will describe general pathways involved in the photophysics of a photosensitized process, which can lead to crosslinking due to light excitation of Riboflavin in the cornea. Furthermore, we will elucidate different aspects of reactions that can produce crosslinks, with respect...

  6. Convergent preparation and photophysical characterization of dimaleimide dansyl fluorogens: elucidation of the maleimide fluorescence quenching mechanism.

    Science.gov (United States)

    Guy, Julia; Caron, Karine; Dufresne, Stéphane; Michnick, Stephen W; Skene, W G; Keillor, Jeffrey W

    2007-10-03

    Dimaleimide fluorogens are being developed for application to fluorescent protein labeling. In this method, fluorophores bearing two maleimide quenching groups do not fluoresce until both maleimide groups have undergone thiol addition reactions with the Cys residues of the target protein sequence [J. Am. Chem. Soc. 2005, 127, 559-566]. In this work, a new convergent synthetic route was developed that would allow any fluorophore to be attached via a linker to a dimaleimide moiety in a modular fashion. Series of dimaleimide and dansyl derivatives were thus prepared conveniently and used to elucidate the mechanism of maleimide quenching. Intersystem crossing was ruled out as a potential quenching pathway, based on the absence of a detectable triplet intermediate by laser flash photolysis. Stern-Volmer rate constants were measured with exogenous dimaleimide quenchers and found to be close to the diffusion-controlled limits, consistent with electron transfer being thermodynamically favorable. The thermodynamic feasibility of the photoinduced electron transfer (PET) quenching mechanism was verified by cyclic voltammetry. The redox potentials measured for dansyl and maleimide confirm that electron transfer from the dansyl excited state to a pendant maleimide group is exergonic and is responsible for fluorescence quenching of the fluorogens studied herein. Taking this PET quenching mechanism into account, future fluorogenic protein labeling agents will be designed with spacers of variable length and rigidity to probe the structure-property PET efficiency relationship.

  7. Photophysics of ionic biochromophores

    CERN Document Server

    Brøndsted Nielsen, Steen

    2014-01-01

    This concise guide to studying ionic biochromophores features the first integrated overview of the photophysics of differing classes of biomolecules, from single amino acids to DNA. It includes an appraisal of the latest theories and experimental techniques.

  8. Controlling photophysical properties of ultrasmall conjugated polymer nanoparticles through polymer chain packing

    KAUST Repository

    Piwonski, Hubert Marek; Michinobu, Tsuyoshi; Habuchi, Satoshi

    2017-01-01

    of the development of Pdots. Here we demonstrate that proper control of the physical interactions between the chains is as critical as the molecular design. The unique design of twisted CPs and fine-tuning of the reprecipitation conditions allow us to fabricate

  9. Shipment of a photodynamic therapy agent into model membrane and its controlled release: A photophysical approach.

    Science.gov (United States)

    Karar, Monaj; Paul, Suvendu; Mallick, Arabinda; Majumdar, Tapas

    2018-01-01

    Harmine, an efficient cancer cell photosensitizer (PS), emits intense violet color when it is incorporated in well established self assembly based drug carrier formed by cationic surfactants of identical positive charge of head group but varying chain length, namely, dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB) and cetyltrimethylammonium bromide (CTAB). Micelle entrapped drug emits in the UV region when it interacts with non-toxic β-cyclodextrin (β-CD). Inspired by these unique fluorescence/structural switching properties of the anticancer drug, in the present work we have monitored the interplay of the drug between micelles and non-toxic β-CDs. We have observed that the model membranes formed by micelles differing in their hydrophobic chain length interact with the drug differently. Variation in the surfactant chain length plays an important role for structural switching i.e. in choosing a particular structural form of the drug that will be finally presented to their targets. The present study shows that in case of necessity, the bound drug molecule can be removed from its binding site in a controlled manner by the use of non-toxic β-CD and it is exploited to serve a significant purpose for the removal of excess/unused adsorbed drugs from the model cell membranes. We believe this kind of β-CD driven translocation of drugs monitored by fluorescence switching may find possible applications in controlled release of the drug inside cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. HYDRAULIC SERVO CONTROL MECHANISM

    Science.gov (United States)

    Hussey, R.B.; Gottsche, M.J. Jr.

    1963-09-17

    A hydraulic servo control mechanism of compact construction and low fluid requirements is described. The mechanism consists of a main hydraulic piston, comprising the drive output, which is connected mechanically for feedback purposes to a servo control piston. A control sleeve having control slots for the system encloses the servo piston, which acts to cover or uncover the slots as a means of controlling the operation of the system. This operation permits only a small amount of fluid to regulate the operation of the mechanism, which, as a result, is compact and relatively light. This mechanism is particuiarly adaptable to the drive and control of control rods in nuclear reactors. (auth)

  11. Nonholonomic mechanics and control

    CERN Document Server

    Murray, RM

    2015-01-01

    This book explores some of the connections between control theory and geometric mechanics; that is, control theory is linked with a geometric view of classical mechanics in both its Lagrangian and Hamiltonian formulations and in particular with the theory of mechanical systems subject to motion constraints. The synthesis of the topic is appropriate as there is a particularly rich connection between mechanics and nonlinear control theory. The book provides a unified treatment of nonlinear control theory and constrained mechanical systems and illustrates the elegant mathematics behind many simple, interesting, and useful mechanical examples. It is intended for graduate students who wish to learn this subject and researchers in the area who want to enhance their techniques. The book contains sections focusing on physical examples and elementary terms, as well as theoretical sections that use sophisticated analysis and geometry. The first four chapters offer preliminaries and background information, while the...

  12. Photophysics Applied to Cavitands and Capsules.

    Science.gov (United States)

    Berryman, Orion B; Dube, Henry; Rebek, Julius

    2011-07-01

    The use of light as a stimulus to control functional materials or nano-devices is appealing as it provides convenient control of triggering events where and when they are desired without introducing extra components to the system. Many photophysical and photochemical processes are extremely fast, giving rise to nearly instantaneous onset of events. However, these fast processes can be challenging to engineer into chemical systems. Supramolecular chemistry offers a convenient way to study and control photoprocesses. Given the reversible and self-programmed nature of modern host-guest systems, a modular approach can be considered in which different photoprocesses are coupled to obtain complex functions that emerge and are controlled solely by light inputs. In this review, we highlight recent examples of photoswitching and photophysics applied in the context of supramolecular host-guest systems, with a particular emphasis on resorcinarene based cavitands and hydrogen bonded capsules.

  13. Control rod driving mechanism

    International Nuclear Information System (INIS)

    Ooshima, Yoshio.

    1983-01-01

    Purpose: To perform reliable scram operation, even if abnormality should occur in a system instructing scram operation in FBR type reactors. Constitution: An aluminum alloy member to be melt at a predetermined temperature (about 600sup(o)C) is disposed to a connection part between a control rod and a driving mechanism, whereby the control rod is detached from the driving mechanism and gravitationally fallen to the reactor core. (Ikeda, J.)

  14. Mechanisms in environmental control

    International Nuclear Information System (INIS)

    Lindeneg, K.

    1994-01-01

    The theory of implementation provides methods for decentralization of decisions in societies. By using mechanisms (game forms) it is possible (in theory) to implement attractive states in different economic environments. As an example the market mechanisms can implement Pareto-efficient and individual rational allocations in an Arrow-Debreu economic environment without market failures. And even when there exists externalities the market mechanism sometime can be used if it is possible to make a market for the goods not allocated on a market already - examples are marketable emission permits, and deposit refund systems. But environmental problems can often be explained by the existence of other market failures (e.g. asymmetric information), and then the market mechanism do not work properly. And instead of using regulation or traditional economic instruments (subsidies, charges, fees, liability insurance, marketable emission permits, or deposit refund systems) to correct the problems caused by market failures, some other methods can be used to deal with these problems. This paper contains a survey of mechanisms that can be used in environmental control when the problems are caused by the existence of public goods, externalities, asymmetric information, and indivisible goods in the economy. By examples it will be demonstrated how the Clarke-Groves mechanism, the Cournot-Lindahl mechanism, and other mechanisms can be used to solve specific environmental problems. This is only theory and examples, but a recent field study have used the Cournot-Lindahl mechanism to solve the problem of lake liming in Sweden. So this subject may be of some interests for environmental policy in the future. (au) 23 refs

  15. Control rod drive mechanism

    International Nuclear Information System (INIS)

    Futatsugi, Masao; Goto, Mikihiko.

    1976-01-01

    Purpose: To provide a control rod drive mechanism using water as an operating source, which prevents a phenomenon for forming two-layers of water in the neighbourhood of a return nozzle in a reactor to limit formation of excessive thermal stress to improve a safety. Constitution: In the control rod drive mechanism of the present invention, a heating device is installed in the neighbourhood of a pressure container for a reactor. This heating device is provided to heat return water in the reactor to a level equal to the temperature of reactor water thereby preventing a phenomenon for forming two-layers of water in the reactor. This limits formation of thermal stress in the return nozzle in the reactor. Accordingly, it is possible to minimize damages in the return nozzle portion and yet a possibility of failure in reactor water. (Kawakami, Y.)

  16. Synthesis, dynamics and photophysics of nanoscale systems

    Science.gov (United States)

    Mirkovic, Tihana

    The emerging field of nanotechnology, which spans diverse areas such as nanoelectronics, medicine, chemical and pharmaceutical industries, biotechnology and computation, focuses on the development of devices whose improved performance is based on the utilization of self-assembled nanoscale components exhibiting unique properties owing to their miniaturized dimensions. The first phase in the conception of such multifunctional devices based on integrated technologies requires the study of basic principles behind the functional mechanism of nanoscale components, which could originate from individual nanoobjects or result as a collective behaviour of miniaturized unit structures. The comprehensive studies presented in this thesis encompass the mechanical, dynamical and photophysical aspects of three nanoscale systems. A newly developed europium sulfide nanocrystalline material is introduced. Advances in synthetic methods allowed for shape control of surface-functionalized EuS nanocrystals and the fabrication of multifunctional EuS-CdSe hybrid particles, whose unique structural and optical properties hold promise as useful attributes of integrated materials in developing technologies. A comprehensive study based on a new class of multifunctional nanomaterials, derived from the basic unit of barcoded metal nanorods is presented. Their chemical composition affords them the ability to undergo autonomous motion in the presence of a suitable fuel. The nature of their chemically powered self-propulsion locomotion was investigated, and plausible mechanisms for various motility modes were presented. Furthermore functionalization of striped metallic nanorods has been realized through the incorporation of chemically controlled flexible hinges displaying bendable properties. The structural aspect of the light harvesting machinery of a photosynthetic cryptophyte alga, Rhodomonas CS24, and the mobility of the antenna protein, PE545, in vivo were investigated. Information obtained

  17. Controllable synthesis of Eu{sup 3+}/Tb{sup 3+} activated lutetium fluorides nanocrystals and their photophysical properties

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jintai; Huo, Jiansheng [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Cai, Yuepeng [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China)

    2013-12-15

    In this paper, phosphors of LuF{sub 3}:Eu{sup 3+}/Tb{sup 3+} have been successfully synthesized with small chelator ethylenediaminetetra acetic acid (EDTA) or amphiphilic polymer (polyethylene glycol, PEG-1000) as templates via a hydrothermal method. X-ray powder diffraction (XRD), scanning electronic microscope (SEM), and photo-luminescent spectra techniques (PL) were used to characterize the as-prepared samples. XRD patterns showed that well crystallized lanthanide fluorides with hexagonal phase were achieved. SEM images revealed that different regular microstructures were achieved. The photo-luminescent properties of LuF{sub 3}:Eu{sup 3+} demonstrated that there are significant energy transfers from fluorides to Eu{sup 3+}. The results presented that EDTA as the template will lead to the highest emission intensities. -- Highlights: • Various templates were used to synthesize LuF{sub 3}:Eu{sup 3+}/Tb{sup 3+}. • All the phosphors were red or green emissive. • Different morphologies were acquired and controllable.

  18. Control rod drive mechanism

    International Nuclear Information System (INIS)

    Nakamura, Akira.

    1981-01-01

    Purpose: To ensure the scram operation of a control rod by the reliable detection for the position of control rods. Constitution: A permanent magnet is provided to the lower portion of a connecting rod in engagement with a control rod and a tube having a plurality of lead switches arranged axially therein in a predetermined pitch is disposed outside of the control rod drives. When the control rod moves upwardly in the scram operation, the lead switches are closed successively upon passage of the permanent magnet to operate the electrical circuit provided by way of each of the lead switches. Thus, the position for the control rod during the scram can reliably be determined and the scram characteristic of the control rod can be recognized. (Furukawa, Y.)

  19. Fluorescent zinc sensor with minimized proton-induced interferences: photophysical mechanism for fluorescence turn-on response and detection of endogenous free zinc ions.

    Science.gov (United States)

    Kwon, Ji Eon; Lee, Sumin; You, Youngmin; Baek, Kyung-Hwa; Ohkubo, Kei; Cho, Jaeheung; Fukuzumi, Shunichi; Shin, Injae; Park, Soo Young; Nam, Wonwoo

    2012-08-20

    A new fluorescent zinc sensor (HNBO-DPA) consisting of 2-(2'-hydroxy-3'-naphthyl)benzoxazole (HNBO) chromophore and a di(2-picolyl)amine (DPA) metal chelator has been prepared and examined for zinc bioimaging. The probe exhibits zinc-induced fluorescence turn-on without any spectral shifts. Its crystal structure reveals that HNBO-DPA binds a zinc ion in a pentacoordinative fashion through the DPA and HNBO moieties. Steady-state photophysical studies establish zinc-induced deprotonation of the HNBO group. Nanosecond and femtosecond laser flash photolysis and electrochemical measurements provide evidence for zinc-induced modulation of photoinduced electron transfer (PeT) from DPA to HNBO. Thus, the zinc-responsive fluorescence turn-on is attributed to suppression of PeT exerted by deprotonation of HNBO and occupation of the electron pair of DPA, a conclusion that is further supported by density functional theory and time-dependent density functional theory (DFT/TD-DFT) calculations. Under physiological conditions (pH 7.0), the probe displays a 44-fold fluorescence turn-on in response to zinc ions with a K(d) value of 12 pM. The fluorescent response of the probe to zinc ions is conserved over a broad pH range with its excellent selectivity for zinc ions among biologically relevant metal ions. In particular, its sensing ability is not altered by divalent transition metal ions such as Fe(II), Cu(II), Cd(II), and Hg(II). Cell experiments using HNBO-DPA show its suitability for monitoring intracellular zinc ions. We have also demonstrated applicability of the probe to visualize intact zinc ions released from cells that undergo apoptosis. More interestingly, zinc-rich pools in zebrafish embryos are traced with HNBO-DPA during early developmental stages. The results obtained from the in vitro and in vivo imaging studies demonstrate the practical usefulness of the probe to detect zinc ions.

  20. Control rod drive mechanism

    International Nuclear Information System (INIS)

    Mizuno, Katsuyuki.

    1976-01-01

    Object: To restrict the reduction in performance due to stress corrosion cracks by making use of condensate produced in a turbine steam condenser. Structure: Water produced in a turbine steam condenser is forced into a condensed water desalting unit by low pressure condensate pump. The condensate is purified and then forced by a high pressure condensate pump into a feedwater heater for heating before it is returned to the reactor by a feedwater pump. Part of the condensate issuing from the condensate desalting unit is branched from the remaining portion at a point upstream the pump and is withdrawn into a control rod drive water pump after passing through a motordriven bypass valve, an orifice and a condenser water level control valve, is pressurized in the control rod drive water desalting unit and supplied to a control rod drive water pressure system. The control rod is vertically moved by the valve operation of the water pressure system. Since water of high oxygen concentration does not enter during normal operation, it is possible to prevent the stress cracking of the stainless steel apparatus. (Nakamura, S.)

  1. An ultrahigh vacuum monochromator for photophysics beamline

    International Nuclear Information System (INIS)

    Meenakshi Raja Rao, P.; Padmanabhan, Saraswathy; Raja Sekhar, B.N.; Shastri, Aparna; Khan, H.A.; Sinha, A.K.

    2000-08-01

    The photophysics beamline designed for carrying out photoabsorption and fluorescence studies using the 450 MeV Synchrotron Radiation Source (SRS), INDUS-1, uses a 1 metre monochromator as premonochromator for monochromatising the continuum. An ultra high vacuum compatible monochromator in Seya-Namioka mount has been designed and fabricated indigenously. The monochromator was assembled and tested for its performance. Wavelength scanning mechanism was tested for its reproducibility and the monochromator was tested for its resolution using UV and VUV sources. An average spectral resolution of 2.5 A was achieved using a 1200 gr/mm grating. A wavelength repeatability of ± 1A was obtained. An ultra high vacuum of 2 X 10 -8 mbar was also achieved in the monochromator. Details of fabrication, assembly and testing are presented in this report. (author)

  2. Photophysical properties of pyronin dyes in reverse micelles of AOT

    Energy Technology Data Exchange (ETDEWEB)

    Bayraktutan, Tuğba; Meral, Kadem; Onganer, Yavuz, E-mail: yonganer@atauni.edu.tr

    2014-01-15

    The photophysical properties of pyronin B (PyB) and pyronin Y (PyY) in reverse micelles formed with water/sodium bis (2-ethyl-1-hexyl) sulfosuccinate (AOT)/n-heptane were investigated by UV–vis absorption, steady-state and time-resolved fluorescence spectroscopy techniques. This study was carried out a wide range of reverse micelle sizes, with hydrodynamic radii ranging from 1.85 to 9.38 nm. Significant photophysical parameters as band shifts, fluorescence quantum yields and fluorescence lifetimes were determined to understand how photophysical and spectroscopic features of the dye compounds were affected by the variation of reverse micelle sizes. In this regard, control of reverse micelle size by changing W{sub 0}, the molar ratio of water to surfactant, allowed tuning the photophysical properties of the dyes in organic solvent via reverse micelle. Non-fluorescent H-aggregates of pyronin dyes were observed for the smaller reverse micelles whereas an increase in the reverse micelle size induced an increment in the amount of dye monomers instead of dye aggregates. Thus, the fluorescence intensities of the dyes were improved by increasing W{sub 0} due to the predomination of the fluorescent dye monomers. As a result, the fluorescence quantum yields also increased. The fluorescence lifetimes of the dyes in the reverse micelles were determined by the time-resolved fluorescence decay studies. Evaluation of the fluorescence lifetimes calculated for pyronin dyes in the reverse micelles showed that the size of reverse micelle affected the fluorescence lifetimes of pyronin dyes. -- Highlights: • The photophysical properties of pyronin dyes were examined by spectroscopic techniques. • Optical properties of the dyes were tuned by changing of W{sub 0} values. • The fluorescence lifetime and quantum yield values of the dyes in reverse micelles were discussed.

  3. Control-rod driving mechanism

    International Nuclear Information System (INIS)

    Jodoi, Takashi.

    1976-01-01

    Purpose: To prevent falling of control rods due to malfunction. Constitution: The device of the present invention has a scram function in particular, and uses principally a fluid pressure as a scram accelerating means. The control rod is held by upper and lower holding devices, which are connected by a connecting mechanism. This connecting mechanism is designed to be detachable only at the lower limit of driving stroke of the control rod so that there occurs no erroneous scram resulting from careless disconnection of the connecting mechanism. Further, scramming operation due to own weight of the scram operating portion such as control rod driving shaft may be effected to increase freedom. (Kamimura, M.)

  4. Control mechanisms in franchise systems

    OpenAIRE

    Hass, Jörg

    2012-01-01

    This dissertation answers the question which different control mechanisms exist in a franchise system. It is the first two-sided franchise empirical analysis, regarding all outlets of the franchise system (franchisees and company-owned) as well as the franchisor. On the theoretical side, this dissertation integrates the two main management theories: principal-agent-theory and transaction cost analysis. The results show that there are used different control mechanisms in a franchise sys...

  5. Protonated serotonin: Geometry, electronic structures and photophysical properties

    Science.gov (United States)

    Omidyan, Reza; Amanollahi, Zohreh; Azimi, Gholamhassan

    2017-07-01

    The geometry and electronic structures of protonated serotonin have been investigated by the aim of MP2 and CC2 methods. The relative stabilities, transition energies and geometry of sixteen different protonated isomers of serotonin have been presented. It has been predicted that protonation does not exhibit essential alteration on the S1 ← S0 electronic transition energy of serotonin. Instead, more complicated photophysical nature in respect to its neutral analogue is suggested for protonated system owing to radiative and non-radiative deactivation pathways. In addition to hydrogen detachment (HD), hydrogen/proton transfer (H/PT) processes from ammonium to indole ring along the NH+⋯ π hydrogen bond have been predicted as the most important photophysical consequences of SERH+ at S1 excited state. The PT processes is suggested to be responsible for fluorescence of SERH+ while the HD driving coordinate is proposed for elucidation of its nonradiative deactivation mechanism.

  6. Optimal Control of Mechanical Systems

    Directory of Open Access Journals (Sweden)

    Vadim Azhmyakov

    2007-01-01

    Full Text Available In the present work, we consider a class of nonlinear optimal control problems, which can be called “optimal control problems in mechanics.” We deal with control systems whose dynamics can be described by a system of Euler-Lagrange or Hamilton equations. Using the variational structure of the solution of the corresponding boundary-value problems, we reduce the initial optimal control problem to an auxiliary problem of multiobjective programming. This technique makes it possible to apply some consistent numerical approximations of a multiobjective optimization problem to the initial optimal control problem. For solving the auxiliary problem, we propose an implementable numerical algorithm.

  7. Muscle mechanics and neuromuscular control

    NARCIS (Netherlands)

    Hof, AL

    The purpose of this paper is to demonstrate that the properties of the mechanical system, especially muscle elasticity and limb mass, to a large degree determine force output and movement. This makes the control demands of the central nervous system simpler and more robust. In human triceps surae, a

  8. Burn Control Mechanisms in Tokamaks

    Science.gov (United States)

    Hill, M. A.; Stacey, W. M.

    2015-11-01

    Burn control and passive safety in accident scenarios will be an important design consideration in future tokamak reactors, in particular fusion-fission hybrid reactors, e.g. the Subcritical Advanced Burner Reactor. We are developing a burning plasma dynamics code to explore various aspects of burn control, with the intent to identify feedback mechanisms that would prevent power excursions. This code solves the coupled set of global density and temperature equations, using scaling relations from experimental fits. Predictions of densities and temperatures have been benchmarked against DIII-D data. We are examining several potential feedback mechanisms to limit power excursions: i) ion-orbit loss, ii) thermal instability density limits, iii) MHD instability limits, iv) the degradation of alpha-particle confinement, v) modifications to the radial current profile, vi) ``divertor choking'' and vii) Type 1 ELMs. Work supported by the US DOE under DE-FG02-00ER54538, DE-FC02-04ER54698.

  9. Cellular mechanisms that control mistranslation

    DEFF Research Database (Denmark)

    Reynolds, Noah M; Lazazzera, Beth A; Ibba, Michael

    2010-01-01

    Mistranslation broadly encompasses the introduction of errors during any step of protein synthesis, leading to the incorporation of an amino acid that is different from the one encoded by the gene. Recent research has vastly enhanced our understanding of the mechanisms that control mistranslation...... at the molecular level and has led to the discovery that the rates of mistranslation in vivo are not fixed but instead are variable. In this Review we describe the different steps in translation quality control and their variations under different growth conditions and between species though a comparison...

  10. Acetone photophysics at 282 nm excitation at elevated pressure and temperature. II: Fluorescence modeling

    Science.gov (United States)

    Hartwig, Jason; Raju, Mandhapati; Sung, Chih-Jen

    2017-07-01

    This is the second in a series of two papers that presents an updated fluorescence model and compares with the new experimental data reported in the first paper, as well as the available literature data, to extend the range of acetone photophysics to elevated pressure and temperature conditions. This work elucidates the complete acetone photophysical model in terms of each and every competing radiative and non-radiative rate. The acetone fluorescence model is then thoroughly examined and optimized based on disparity with recently conducted elevated pressure and temperature photophysical calibration experiments. The current work offers insight into the competition between non-radiative and vibrational energy decay rates at elevated temperature and pressure and proposes a global optimization of model parameters from the photophysical model developed by Thurber (Acetone Laser-Induced Fluorescence for Temperature and Multiparameter Imaging in Gaseous Flows. PhD thesis, Stanford University Mechanical Engineering Department, 1999). The collisional constants of proportionality, which govern vibrational relaxation, are shown to be temperature dependent at elevated pressures. A new oxygen quenching rate is proposed which takes into account collisions with oxygen as well as the oxygen-assisted intersystem crossing component. Additionally, global trends in ketone photophysics are presented and discussed.

  11. Synthesis, characterization and photophysical properties of ESIPT reactive triazine derivatives

    International Nuclear Information System (INIS)

    Kuplich, Marcelo D.; Grasel, Fabio S.; Campo, Leandra F.; Rodembusch, Fabiano S.; Stefani, Valter

    2012-01-01

    Four new reactive fluorescent triazine derivatives were obtained from nucleophilic aromatic substitution of cyanuric chloride. The compounds were characterized by infrared spectroscopy (IR), nuclear magnetic resonance ( 13 C and 1 H NMR) and high resolution mass spectrometry (HRMS MALDI). UV-Vis and steady-state fluorescence (in solution and in solid state) spectroscopies were also applied to characterize the photophysical behavior. The dyes are fluorescent by an intramolecular proton transfer mechanism (ESIPT) in the blue-orange region, with a large Stokes shift between 6365-10290 cm-1. The fluorescent cyanuric derivatives could successfully react with cellulose fibers to give new fluorescent cellulosic materials. (author)

  12. Photochemistry and photophysics concepts, research, applications

    CERN Document Server

    Balzani , Vincenzo; Juris, Alberto

    2014-01-01

    This textbook covers the spectrum from basic concepts of photochemistry and photophysics to selected examples of current applications and research.Clearly structured, the first part of the text discusses the formation, properties and reactivity of excited states of inorganic and organic molecules and supramolecular species, as well as experimental techniques. The second part focuses on the photochemical and photophysical processes in nature and artificial systems, using a wealth of examples taken from applications in nature, industry and current research fields, ranging from natural photosynth

  13. Control mechanisms for ecological-economic systems

    CERN Document Server

    Burkov, Vladimir N; Shchepkin, Alexander V

    2015-01-01

    This monograph presents and analyzes the optimization, game-theoretic and simulation models of control mechanisms for ecological-economic systems. It is devoted to integrated assessment mechanisms for total risks and losses, penalty mechanisms, risk payment mechanisms, financing and costs compensation mechanisms for risk level reduction, sales mechanisms for risk level quotas, audit mechanisms, mechanisms for expected losses reduction, economic motivation mechanisms, optimization mechanisms for regional environmental (risk level reduction) programs, and mechanisms for authorities' interests coordination. The book is aiming at undergraduate and postgraduate students, as well as at experts in mathematical modeling and control of ecological economic, socioeconomic and organizational systems.

  14. Photoprotection and the photophysics of acylated anthocyanins.

    Science.gov (United States)

    da Silva, Palmira Ferreira; Paulo, Luísa; Barbafina, Adrianna; Eisei, Fausto; Quina, Frank H; Maçanita, António L

    2012-03-19

    The proposed role of anthocyanins in protecting plants against excess solar radiation is consistent with the occurrence of ultrafast (5-25 ps) excited-state proton transfer as the major de-excitation pathway of these molecules. However, because natural anthocyanins absorb mainly in the visible region of the spectra, with only a narrow absorption band in the UV-B region, this highly efficient deactivation mechanism would essentially only protect the plant from visible light. On the other hand, ground-state charge-transfer complexes of anthocyanins with naturally occurring electron-donor co-pigments, such as hydroxylated flavones, flavonoids, and hydroxycinnamic or benzoic acids, do exhibit high UV-B absorptivities that complement that of the anthocyanins. In this work, we report a comparative study of the photophysics of the naturally occurring anthocyanin cyanin, intermolecular cyanin-coumaric acid complexes, and an acylated anthocyanin, that is, cyanin with a pendant coumaric ester co-pigment. Both inter- and intramolecular anthocyanin-co-pigment complexes are shown to have ultrafast energy dissipation pathways comparable to those of model flavylium cation-co-pigment complexes. However, from the standpoint of photoprotection, the results indicate that the covalent attachment of co-pigment molecules to the anthocyanin represents a much more efficient strategy by providing the plant with significant UV-B absorption capacity and at the same time coupling this absorption to efficient energy dissipation pathways (ultrafast internal conversion of the complexed form and fast energy transfer from the excited co-pigment to the anthocyanin followed by adiabatic proton transfer) that avoid net photochemical damage. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Control mechanisms in corporate governance

    Directory of Open Access Journals (Sweden)

    Jovanović-Zattila Milena

    2016-01-01

    Full Text Available The structure of corporate governance is determined by the distribution of rights and responsibilities among different actors in the company structure. Organizationally complex structure of corporate entities, established as a reflection of composite forms of business corporations, give rise to the conflict of interest between the owners, the board of directors and managers, which is generally known as the principal-agency problem. Given the fact that operations of modern companies include interaction with a large number of stakeholders, matters of ethics and accountability to the owners, employees, creditors and the state are the basic postulates which have been subject to re-examination lately. The reasons for reassessing these issues are to be sought in numerous abuses by companies, which are on the other hand highly active in their effors to protect themselves from similar abuses (mainy cyber crime. In order to respond to new challenges and requirements, which include providing for the interests of both shareholders and stakeholders, corporate management is required to establish an adequate system of internal control covering all company activities. Contemporary trends in the development of internal audit, as a mechanism of good corporate governance, are reflected in providing advice in respect of anticipated future risks and risk management.

  16. Control of a mechanical gripper with a fuzzy controller

    International Nuclear Information System (INIS)

    Alberdi, J.; Barcala, J.M.; Gamero, E.; Navarrete, J.J.

    1995-01-01

    A fuzzy logic system is used to control a mechanical gripper. System is based in a NLX230 fuzzy micro controller. Control rules are programmed by a 68020 microprocessor in the micro controller memory. Stress and its derived are used as feedback signals in the control. This system can adapt its effort to the mechanical resistance of the object between the fingers. (Author)

  17. Rationalizing substituent effects in 1-azathioxanthone photophysics

    Science.gov (United States)

    Junker, Anne Kathrine R.; Just Sørensen, Thomas

    2018-01-01

    The influence of an electron donating substituent on the photophysical properties of 1-azathioxanthone dyes has been investigated using optical spectroscopy and theoretical models. The motivation behind the study is based on the fact that thioxanthones are efficient triplet sensitizers, and thus promising sensitizers for lanthanide centered emission. By adding an aza group to one of the phenyl ring systems, direct coordination to a lanthanide center becomes possible, which makes azathoixanthones great candidates as antenna chromophores in lanthanide(III) based dyes. Here, three 1-azathioxanthone derivatives have been synthesized targeting efficient triplet formation following absorption in the visible range of the spectrum. This is achieved by adding methoxy groups to the 1-azathioxanthone core. The derivatives were characterized using absorption, emission, and time-gated emission spectroscopy, where fluorescent quantum yields, singlet and triplet excited states lifetimes were determined. The experimentally determined photophysical properties of the three 1-azathioxanthone compounds are contrasted to those of the parent thioxanthone and is rationalized using the Strickler-Berg equation, Hückel MO theory, and Dewar’s rules in combination with computational chemistry. We find that the transition energies follow predictions, but that the overall photophysical properties are determined by the relative energies as well as the nature of the involved states in both the singlet and the triplet excited state manifolds.

  18. Synthesis and Photophysical Characterizations of Thermal -Stable Naphthalene Benzimidazoles

    OpenAIRE

    Erten Ela, Şule; Özçelik, Serdar; Eren, Ersin

    2011-01-01

    Microwave-assisted synthesis, photophysical and electrochemical properties of thermal-stable naphthalene benzimidazoles and naphthalimides are studied in this paper. Microwave-assisted synthesis of naphthalene benzimidazoles provide higher yields than the conventional thermal synthesis. Comparative photophysical properties of naphthalene benzimidazoles and naphthalimides are revealed that conjugation of electron-donating group onto naphthalimide moiety increases fluorescence ...

  19. Photophysics and photochemistry of photoreactivation

    International Nuclear Information System (INIS)

    Sutherland, J.C.

    1977-01-01

    Photoreactivating enzyme (PRE) monomerizes cyclobutyl pyrimidine dimers formed in DNA by UV light (lambda < 300 nm). The enzyme requires near UV and visible wavelengths (300 < lambda < 600 nm) for activity. Possible mechanisms of action of the PRE are suggested by non-enzymatic processes in which pyrimidine dimers are monomerized by UV and visible light. Two such non-enzymatic processes are (a) photolysis of dimers resulting from direct absorption of UV, and (b) sensitized monomerization involving charge transfer complexes. Several lines of evidence suggest that the mechanism of action of the PRE more closely resembles (b) than (a). Recent experiments on the PRE from E.coli revealed the presence of new long wavelength absorption which may indicate the presence of a ground state complex. The known ability of PRE to monomerize dimers of thymine, cytosine and uracil suggests that the carbonyl groups at 2 position of the pyrimidine ring may be important in the interaction between enzyme and dimer. (author)

  20. Photophysics and photochemistry of photoreactivation

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, J C [California Univ., Irvine (USA)

    1977-05-01

    Photoreactivating enzyme (PRE) monomerizes cyclobutyl pyrimidine dimers formed in DNA by uv light (lambda < 300 nm). The enzyme requires near UV and visible wavelengths (300 < lambda < 600 nm) for activity. Possible mechanisms of action of the PRE are suggested by non-enzymatic processes in which pyrimidine dimers are monomerized by UV and visible light. Two such non-enzymatic processes are (a) photolysis of dimers resulting from direct absorption of UV, and (b) sensitized monomerization involving charge transfer complexes. Several lines of evidence suggest that the mechanism of action of the PRE more closely resembles (b) than (a). Recent experiments on the PRE from E.coli revealed the presence of new long wavelength absorption which may indicate the presence of a ground state complex. The known ability of PRE to monomerize dimers of thymine, cytosine and uracil suggests that the carbonyl groups at 2 position of the pyrimidine ring may be important in the interaction between enzyme and dimer.

  1. Drive mechanism nuclear reactor control rod

    International Nuclear Information System (INIS)

    Brooks, J.G. Jr.; Maure, D.R.; Meijer, C.H.

    1978-01-01

    An improved method and apparatus for operating magnetic stepping-type mechanisms. The current flowing in the coils of magnetic stepping-type mechanisms of the kind, for instance, that are used in control-element drive mechanisms is sensed and used to monitor operation of the mechanism. Current waveforms that characterize the motion of the mechanism are used to trigger changes in drive voltage and to verify that the drive mechanism is operating properly. In addition, incipient failures are detected through the observation of differences between the observed waveform and waveforms that characterize proper operation

  2. Photophysical properties of coumarin-120: Unusual behavior in nonpolar solvents

    International Nuclear Information System (INIS)

    Pal, Haridas; Nad, Sanjukta; Kumbhakar, Manoj

    2003-01-01

    Photophysical properties of coumarin-120 (C120; 7-amino-4-methyl-1,2-benzopyrone) dye have been investigated in different solvents using steady-state and time-resolved fluorescence and picosecond laser flash photolysis (LFP) and nanosecond pulse radiolysis (PR) techniques. C120 shows unusual photophysical properties in nonpolar solvents compared to those in other solvents of moderate to higher polarities. Where the Stokes shifts (Δν-bar=ν-bar abs -ν-bar fl ), fluorescence quantum yields (Φ f ), and fluorescence lifetimes (τ f ) show more or less linear correlation with the solvent polarity function Δf={(ε-1)/(2ε+1)-(n 2 -1)/(2n 2 +1)}, all these parameters are unusually lower in nonpolar solvents. Unlike in other solvents, both Φ f and τ f in nonpolar solvents are also strongly temperature dependent. It is indicated that the excited singlet (S 1 ) state of C120 undergoes a fast activation-controlled nonradiative deexcitation in nonpolar solvents, which is absent in all other solvents. LFP and PR studies indicate that the intersystem crossing process is negligible for the present dye in all the solvents studied. Photophysical behavior of C120 in nonpolar solvent has been rationalized assuming that in these solvents the dye exists in a nonpolar structure, with its 7-NH 2 group in a pyramidal configuration. In this structure, since the 7-NH 2 group is bonded to the 1,2-benzopyrone moiety by a single bond, the former group can undergo a fast flip-flop motion, which in effect causes the fast nonradiative deexcitation of the dye excited state. In moderate to higher polarity solvents, it is indicated that the dye exists in an intramolecular charge-transfer structure, where the bond between 7-NH 2 group and the 1,2-benzopyrone moiety attains substantial double bond character. In this structure, the flip-flop motion of the 7-NH 2 group is highly restricted and thus there is no fast nonradiative deexcitation process for the excited dye

  3. Mechanical engineers' handbook, design, instrumentation, and controls

    CERN Document Server

    Kutz, Myer

    2015-01-01

    Full coverage of electronics, MEMS, and instrumentation andcontrol in mechanical engineering This second volume of Mechanical Engineers' Handbookcovers electronics, MEMS, and instrumentation and control, givingyou accessible and in-depth access to the topics you'll encounterin the discipline: computer-aided design, product design formanufacturing and assembly, design optimization, total qualitymanagement in mechanical system design, reliability in themechanical design process for sustainability, life-cycle design,design for remanufacturing processes, signal processing, dataacquisition and dis

  4. Tracking Control of Nonlinear Mechanical Systems

    NARCIS (Netherlands)

    Lefeber, A.A.J.

    2000-01-01

    The subject of this thesis is the design of tracking controllers for certain classes of mechanical systems. The thesis consists of two parts. In the first part an accurate mathematical model of the mechanical system under consideration is assumed to be given. The goal is to follow a certain

  5. Computational Photophysics in the Presence of an Environment

    Science.gov (United States)

    Nogueira, Juan J.; González, Leticia

    2018-04-01

    Most processes triggered by ultraviolet (UV) or visible (vis) light in nature take place in complex biological environments. The first step in these photophysical events is the excitation of the absorbing system or chromophore to an electronically excited state. Such an excitation can be monitored by the UV-vis absorption spectrum. A precise calculation of the UV-vis spectrum of a chromophore embedded in an environment is a challenging task that requires the consideration of several ingredients, besides an accurate electronic-structure method for the excited states. Two of the most important are an appropriate description of the interactions between the chromophore and the environment and accounting for the vibrational motion of the whole system. In this contribution, we review the most common theoretical methodologies to describe the environment (including quantum mechanics/continuum and quantum mechanics/molecular mechanics models) and to account for vibrational sampling (including Wigner sampling and molecular dynamics). Further, we illustrate in a series of examples how the lack of these ingredients can lead to a wrong interpretation of the electronic features behind the UV-vis absorption spectrum.

  6. Photophysical properties of some xanthylium salts performances under CVL pumping

    International Nuclear Information System (INIS)

    Doizi, D.; Lompre, L.A.; Gazeau, M.C.

    1995-01-01

    We report the photochemical and photophysical performances of some new dyes belonging to the xanthylium salts family. Performances under Copper Vapor Laser (CVL) pumping are described and compared to those of Rhodamine 6G. (author)

  7. Synthesis, photophysical and preliminary investigation of the dye

    Indian Academy of Sciences (India)

    Synthesis, photophysical and preliminary investigation of the dye-sensitized solar ... with most reduction potential which might be due to increase in the conjugation of ... CSIR Materials Science and Manufacturing, PO Box 395, Pretoria 0001, ...

  8. Nonsmooth mechanics models, dynamics and control

    CERN Document Server

    Brogliato, Bernard

    2016-01-01

    Now in its third edition, this standard reference is a comprehensive treatment of nonsmooth mechanical systems refocused to give more prominence to control and modelling. It covers Lagrangian and Newton–Euler systems, detailing mathematical tools such as convex analysis and complementarity theory. The ways in which nonsmooth mechanics influence and are influenced by well-posedness analysis, numerical analysis and simulation, modelling and control are explained. Contact/impact laws, stability theory and trajectory-tracking control are given in-depth exposition connected by a framework formed from complementarity systems and measure-differential inclusions. Links are established with electrical circuits with set-valued nonsmooth elements and with other nonsmooth dynamical systems like impulsive and piecewise linear systems. Nonsmooth Mechanics (third edition) has been substantially rewritten, edited and updated to account for the significant body of results that have emerged in the twenty-first century—incl...

  9. Bell trajectories for revealing quantum control mechanisms

    International Nuclear Information System (INIS)

    Dennis, Eric; Rabitz, Herschel

    2003-01-01

    The dynamics induced while controlling quantum systems by optimally shaped laser pulses have often been difficult to understand in detail. A method is presented for quantifying the importance of specific sequences of quantum transitions involved in the control process. The method is based on a ''beable'' formulation of quantum mechanics due to John Bell that rigorously maps the quantum evolution onto an ensemble of stochastic trajectories over a classical state space. Detailed mechanism identification is illustrated with a model seven-level system. A general procedure is presented to extract mechanism information directly from closed-loop control experiments. Application to simulated experimental data for the model system proves robust with up to 25% noise

  10. Macro-mechanics controls quantum mechanics: mechanically controllable quantum conductance switching of an electrochemically fabricated atomic-scale point contact.

    Science.gov (United States)

    Staiger, Torben; Wertz, Florian; Xie, Fangqing; Heinze, Marcel; Schmieder, Philipp; Lutzweiler, Christian; Schimmel, Thomas

    2018-01-12

    Here, we present a silver atomic-scale device fabricated and operated by a combined technique of electrochemical control (EC) and mechanically controllable break junction (MCBJ). With this EC-MCBJ technique, we can perform mechanically controllable bistable quantum conductance switching of a silver quantum point contact (QPC) in an electrochemical environment at room temperature. Furthermore, the silver QPC of the device can be controlled both mechanically and electrochemically, and the operating mode can be changed from 'electrochemical' to 'mechanical', which expands the operating mode for controlling QPCs. These experimental results offer the perspective that a silver QPC may be used as a contact for a nanoelectromechanical relay.

  11. Mechanical perturbation control of cardiac alternans

    Science.gov (United States)

    Hazim, Azzam; Belhamadia, Youssef; Dubljevic, Stevan

    2018-05-01

    Cardiac alternans is a disturbance in heart rhythm that is linked to the onset of lethal cardiac arrhythmias. Mechanical perturbation control has been recently used to suppress alternans in cardiac tissue of relevant size. In this control strategy, cardiac tissue mechanics are perturbed via active tension generated by the heart's electrical activity, which alters the tissue's electric wave profile through mechanoelectric coupling. We analyze the effects of mechanical perturbation on the dynamics of a map model that couples the membrane voltage and active tension systems at the cellular level. Therefore, a two-dimensional iterative map of the heart beat-to-beat dynamics is introduced, and a stability analysis of the system of coupled maps is performed in the presence of a mechanical perturbation algorithm. To this end, a bidirectional coupling between the membrane voltage and active tension systems in a single cardiac cell is provided, and a discrete form of the proposed control algorithm, that can be incorporated in the coupled maps, is derived. In addition, a realistic electromechanical model of cardiac tissue is employed to explore the feasibility of suppressing alternans at cellular and tissue levels. Electrical activity is represented in two detailed ionic models, the Luo-Rudy 1 and the Fox models, while two active contractile tension models, namely a smooth variant of the Nash-Panfilov model and the Niederer-Hunter-Smith model, are used to represent mechanical activity in the heart. The Mooney-Rivlin passive elasticity model is employed to describe passive mechanical behavior of the myocardium.

  12. Mechanical components design for PWR - control rod drive mechanism

    International Nuclear Information System (INIS)

    Leme, Francisco Louzano; Mattar Neto, Miguel

    2002-01-01

    The Control Rod Drive Mechanism (CRDM) is usually - a high precision - equipment incorporating mechanical and electrical components designed to move the control rods. The 'control rods' refer to all rods or assemblies that are moved to assess the performance of the reactor. The CRDM here presented is the Nut and Lead Screw type. This type is basically a power screw type magnetically coupled to a slow speed reluctance electric motor that provides a means of axially positioning the movable fuel assemblies in the reactor core for purpose of controlling core reactivity. A helically threaded lead screw assembly, comprising one element of power screw, is attached to a movable fuel assemblies. The CRDM usually has closer and more consistent contact with environment peculiar to the reactor than has only other machinery component. This environment includes not only the radiation field of the reactor, but also the temperature, pressure and chemical properties associated with the material used as the coolant for reactor fuel. Specific and special materials are needed because of the above mentioned application. Due to the importance of the above described CRDM functions, this paper will also consider the nuclear functions and their safety classes as well as the CRDM nuclear design criteria. (author)

  13. Damper mechanism for nuclear reactor control elements

    International Nuclear Information System (INIS)

    Taft, W.E.

    1976-01-01

    A damper mechanism which provides a nuclear reactor control element decelerating function at the end of the scram stroke is described. The total damping function is produced by the combination of two assemblies, which operate in sequence. First, a tapered dashram assembly decelerates the control element to a lower velocity, after which a spring hydraulic damper assembly takes over to complete the final damping. 3 claims, 2 figures

  14. Education as a Social Control Mechanism.

    Science.gov (United States)

    Bacchus, M. K.

    1979-01-01

    With the abolition of slavery, most West Indian planters dramatically changed their attitudes toward education for Blacks, suddenly favoring it. This paper examines reasons behind the attitudinal changes, the planters' perceptions on the role of education for Blacks, and the use of education as a mechanism for social control. (DS)

  15. Macro-mechanics controls quantum mechanics: mechanically controllable quantum conductance switching of an electrochemically fabricated atomic-scale point contact

    Science.gov (United States)

    Staiger, Torben; Wertz, Florian; Xie, Fangqing; Heinze, Marcel; Schmieder, Philipp; Lutzweiler, Christian; Schimmel, Thomas

    2018-01-01

    Here, we present a silver atomic-scale device fabricated and operated by a combined technique of electrochemical control (EC) and mechanically controllable break junction (MCBJ). With this EC-MCBJ technique, we can perform mechanically controllable bistable quantum conductance switching of a silver quantum point contact (QPC) in an electrochemical environment at room temperature. Furthermore, the silver QPC of the device can be controlled both mechanically and electrochemically, and the operating mode can be changed from ‘electrochemical’ to ‘mechanical’, which expands the operating mode for controlling QPCs. These experimental results offer the perspective that a silver QPC may be used as a contact for a nanoelectromechanical relay.

  16. Control mechanisms for Nordic ship emissions

    Energy Technology Data Exchange (ETDEWEB)

    Martinsen, K. [DNV, Oslo (Norway); Torvanger, A. [Cicero, Oslo (Norway)

    2013-04-15

    Shipping today operates under a complex set of international and domestic regulations. However, the environmental regulations have lagged behind those of other industries. This situation is now changing quite dramatically. The increased focus on environmental issues, combined with the growing realisation of the actual pollution burden imposed by shipping, has led to an upsurge in both international and national regulations. Some are ready and will enter into force in the near future, while others are still being developed. On behalf of the Nordic Council of Ministers DNV has carried out a study on possible control mechanisms for Nordic ship emission. The aim is to assess the baseline shipping emissions and reduction potential and the possible controlling mechanisms (both incentives and regulations) available for reducing the emissions to air from shipping within the Nordic region. (Author)

  17. Borehole tool outrigger arm displacement control mechanism

    International Nuclear Information System (INIS)

    Lee, A.G.

    1985-01-01

    As the outrigger arms of a borehole logging tool are flexed inwardly and outwardly according to the diameter of the borehole opening through which they pass, the corresponding axial displacements of the ends of the arms are controlled to determine the axial positions of the arms relative to the tool. Specifically, as the arm ends move, they are caused to rotate by a cam mechanism. The stiffness of the arms causes the arm ends to rotate in unison, and the exact positions of the arms on the tool are then controlled by the differential movements of the arm ends in the cams

  18. Towards PSII analogs driven by ruthenium photophysics

    International Nuclear Information System (INIS)

    Olsson, Jerry

    2002-01-01

    A number of model complexes have been prepared in an attempt to develop models for photosystem II (PSII) in green plants. As replacement for the chlorophyll photosensitizer, we have used Ru(ll) tris-2,2-bipyridyl or Ru(ll) bis-2,2';6',2 - terpyridyl complexes linked to a pendant 2,2'-bipyridyl or 2,2';6',2''-terpyridyl moieties via spacers of varying lengths. Manganese (ll) has been covalently linked to the pendant 2,2'-bipyridyl /2,2';6',2''-terpyridyl moieties. The use of different ruthenium centres and spacers has made it possible to make assumptions about the way and how easily manganese is coordinated through self-assembly to the pendant 2,2'-bipyridyl or 2,2';6',2''-terpyridyl groups. Several polynuclear complexes containing a photoactive centre (Ru(ll) tris-2,2'-bipyridine or Ru(ll) bis-2,2';6',2''-terpyridine) or other metal ions (Co 2+ , Fe 2+ , Mn 2= ) have been prepared and characterised. The main work has been focused on organic synthesis and characterisation of polypyridine ligands and coordinated to different metal centres. The complexes have been investigated electrochemically and photophysically. Several new phenol-based ligands have been prepared by organic synthetic methods and characterised by various different methods. (author)

  19. Non-adiabatic Excited State Molecule Dynamics Modeling of Photochemistry and Photophysics of Materials

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Tammie Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tretiak, Sergei [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-06

    Understanding and controlling excited state dynamics lies at the heart of all our efforts to design photoactive materials with desired functionality. This tailor-design approach has become the standard for many technological applications (e.g., solar energy harvesting) including the design of organic conjugated electronic materials with applications in photovoltaic and light-emitting devices. Over the years, our team has developed efficient LANL-based codes to model the relevant photophysical processes following photoexcitation (spatial energy transfer, excitation localization/delocalization, and/or charge separation). The developed approach allows the non-radiative relaxation to be followed on up to ~10 ps timescales for large realistic molecules (hundreds of atoms in size) in the realistic solvent dielectric environment. The Collective Electronic Oscillator (CEO) code is used to compute electronic excited states, and the Non-adiabatic Excited State Molecular Dynamics (NA-ESMD) code is used to follow the non-adiabatic dynamics on multiple coupled Born-Oppenheimer potential energy surfaces. Our preliminary NA-ESMD simulations have revealed key photoinduced mechanisms controlling competing interactions and relaxation pathways in complex materials, including organic conjugated polymer materials, and have provided a detailed understanding of photochemical products and intermediates and the internal conversion process during the initiation of energetic materials. This project will be using LANL-based CEO and NA-ESMD codes to model nonradiative relaxation in organic and energetic materials. The NA-ESMD and CEO codes belong to a class of electronic structure/quantum chemistry codes that require large memory, “long-queue-few-core” distribution of resources in order to make useful progress. The NA-ESMD simulations are trivially parallelizable requiring ~300 processors for up to one week runtime to reach a meaningful restart point.

  20. Mechanics of human voice production and control.

    Science.gov (United States)

    Zhang, Zhaoyan

    2016-10-01

    As the primary means of communication, voice plays an important role in daily life. Voice also conveys personal information such as social status, personal traits, and the emotional state of the speaker. Mechanically, voice production involves complex fluid-structure interaction within the glottis and its control by laryngeal muscle activation. An important goal of voice research is to establish a causal theory linking voice physiology and biomechanics to how speakers use and control voice to communicate meaning and personal information. Establishing such a causal theory has important implications for clinical voice management, voice training, and many speech technology applications. This paper provides a review of voice physiology and biomechanics, the physics of vocal fold vibration and sound production, and laryngeal muscular control of the fundamental frequency of voice, vocal intensity, and voice quality. Current efforts to develop mechanical and computational models of voice production are also critically reviewed. Finally, issues and future challenges in developing a causal theory of voice production and perception are discussed.

  1. Stirling engine control mechanism and method

    Science.gov (United States)

    Dineen, John J.

    1983-01-01

    A reciprocating-to-rotating motion conversion and power control device for a Stirling engine includes a hub mounted on an offset portion of the output shaft for rotation relative to the shaft and for sliding motion therealong which causes the hub to tilt relative to the axis of rotation of the shaft. This changes the angle of inclination of the hub relative to the shaft axis and changes the axial stroke of a set of arms connected to the hub and nutating therewith. A hydraulic actuating mechanism is connected to the hub for moving its axial position along the shaft. A balancing wheel is linked to the hub and changes its angle of inclination as the angle of inclination of the hub changes to maintain the mechanism in perfect balance throughout its range of motion.

  2. The immunological mechanisms that control pneumococcal carriage.

    Directory of Open Access Journals (Sweden)

    Simon P Jochems

    2017-12-01

    Full Text Available Colonization of the human nasopharynx by pneumococcus is extremely common and is both the primary reservoir for transmission and a prerequisite for disease. Current vaccines targeting the polysaccharide capsule effectively prevent colonization, conferring herd protection within vaccinated communities. However, these vaccines cover only a subset of all circulating pneumococcal strains, and serotype replacement has been observed. Given the success of pneumococcal conjugate vaccine (PCV in preventing colonization in unvaccinated adults within vaccinated communities, reducing nasopharyngeal colonization has become an outcome of interest for novel vaccines. Here, we discuss the immunological mechanisms that control nasopharyngeal colonization, with an emphasis on findings from human studies. Increased understanding of these immunological mechanisms is required to identify correlates of protection against colonization that will facilitate the early testing and design of novel vaccines.

  3. Mechanically controllable break junctions for molecular electronics.

    Science.gov (United States)

    Xiang, Dong; Jeong, Hyunhak; Lee, Takhee; Mayer, Dirk

    2013-09-20

    A mechanically controllable break junction (MCBJ) represents a fundamental technique for the investigation of molecular electronic junctions, especially for the study of the electronic properties of single molecules. With unique advantages, the MCBJ technique has provided substantial insight into charge transport processes in molecules. In this review, the techniques for sample fabrication, operation and the various applications of MCBJs are introduced and the history, challenges and future of MCBJs are discussed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Mechanical weed control in organic winter wheat

    OpenAIRE

    Euro Pannacci; Francesco Tei; Marcello Guiducci

    2017-01-01

    Three field experiments were carried out in organic winter wheat in three consecutive years (exp. 1, 2005-06; exp. 2, 2006- 07; exp. 3, 2007-08) in central Italy (42°57’ N - 12°22’ E, 165 m a.s.l.) in order to evaluate the efficacy against weeds and the effects on winter wheat of two main mechanical weed control strategies: i) spring tine harrowing used at three different application times (1 passage at T1, 2 passages at the time T1, 1 passage at T1 followed by 1 passage at T1 + 14 days) in t...

  5. Maintenance of BWR control rod drive mechanisms

    International Nuclear Information System (INIS)

    Greene, R.H.

    1991-01-01

    Control rod drive mechanism (CRDM) replacement and rebuilding is one of the highest dose, most physically demanding, and complicated maintenance activities routinely accomplished by BWR utilities. A recent industry workshop sponsored by the Oak Ridge National Laboratory, which dealt with the effects of CRDM aging, revealed enhancements in maintenance techniques and tooling which have reduced ALARA, improved worker comfort and productivity, and have provided revised guidelines for CRDM changeout selection. Highlights of this workshop and ongoing research on CRDM aging are presented in this paper

  6. Frictionless segmented mechanics for controlled space closure.

    Science.gov (United States)

    Andrade, Ildeu

    2017-02-01

    Extraction spaces may be needed to achieve specific orthodontic goals of positioning the dentition in harmony with the craniofacial complex. However, the fundamental reality that determines the occlusion final position is the control exerted by the orthodontist while closing the extraction spaces. A specific treatment objective may require the posterior teeth to remain in a constant position anteroposteriorly as well as vertically, while the anterior teeth occupy the entire extraction site. Another treatment objective may require the opposite, or any number of intentional alternatives of extraction site closure. The present case report describes a simple controlled segmented mechanic system that permitted definable and predictable force systems to be applied and allowed to predict the treatment outcome with confidence. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO) in partial fulfillment of the requirements for Diplomate certification.

  7. Frictionless segmented mechanics for controlled space closure

    Directory of Open Access Journals (Sweden)

    Ildeu Andrade Jr

    Full Text Available ABSTRACT Extraction spaces may be needed to achieve specific orthodontic goals of positioning the dentition in harmony with the craniofacial complex. However, the fundamental reality that determines the occlusion final position is the control exerted by the orthodontist while closing the extraction spaces. A specific treatment objective may require the posterior teeth to remain in a constant position anteroposteriorly as well as vertically, while the anterior teeth occupy the entire extraction site. Another treatment objective may require the opposite, or any number of intentional alternatives of extraction site closure. The present case report describes a simple controlled segmented mechanic system that permitted definable and predictable force systems to be applied and allowed to predict the treatment outcome with confidence. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO in partial fulfillment of the requirements for Diplomate certification.

  8. Passive cooling of control rod drive mechanisms

    International Nuclear Information System (INIS)

    Hankinson, M.F.; Schwirian, R.E.

    1992-01-01

    A method and apparatus are provided for passively cooling the control rod drive mechanisms (CRDMs) in the reactor vessel of a nuclear power plant. Passive cooling is achieved by dispersing a plurality of chimneys within the CRDM array in positions where a control rod is not required. The chimneys induce convective air currents which cause ambient air from within the containment to flow over the CRDM coils. The air heated by the coils is guided into inlets in the chimneys by baffles. The chimney is insulated and extends through the seismic support platform and missile shield disposed above the closure head. A collar of adjustable height mates with plate elements formed at the distal end of the CRDM pressure housings by an interlocking arrangement so that the seismic support platform provides lateral restraint for the chimneys. (Author)

  9. Gain control mechanisms in spinal motoneurons

    Directory of Open Access Journals (Sweden)

    Michael David Johnson

    2014-07-01

    Full Text Available Motoneurons provide the only conduit for motor commands to reach muscles. For many years, motoneurons were in fact considered to be little more than passive wires. Systematic studies in the past 25 years however have clearly demonstrated that the intrinsic electrical properties of motoneurons are under strong neuromodulatory control via multiple sources. The discovery of potent neuromodulation from the brainstem and its ability to change the gain of motoneurons shows that the passive view of the motor output stage is no longer tenable. A mechanism for gain control at the motor output stage makes good functional sense considering our capability of generating an enormous range of forces, from very delicate (e.g. putting in a contact lens to highly forceful (emergency reactions. Just as sensory systems need gain control to deal with a wide dynamic range of inputs, so to might motor output need gain control to deal with the wide dynamic range of the normal movement repertoire. Two problems emerge from the potential use of the brainstem monoaminergic projection to motoneurons for gain control. First, the projection is highly diffuse anatomically, so that independent control of the gains of different motor pools is not feasible. In fact, the system is so diffuse that gain for all the motor pools in a limb likely increases in concert. Second, if there is a system that increases gain, probably a system to reduce gain is also needed. In this review, we summarize recent studies that show local inhibitory circuits within the spinal cord, especially reciprocal and recurrent inhibition, have the potential to solve both of these problems as well as constitute another source of gain modulation.

  10. UHV mirror mounts for photophysics beamline at Indus-I

    International Nuclear Information System (INIS)

    Meenakshi Raja Rao, P.; Bhattacharya, S.S.; Das, N.C.; Rajasekhar, B.N.; Roy, A.P.

    1995-01-01

    Photophysics beamline makes use of a combination of two toroidal mirrors and one meter Seya-Namioka Monochromator in its fore optics. The fore optics monochromatises and steers the synchrotron radiation source (SRS) beam from its tangent point to the sample situated at a distance of about five meters. Slit widths of the monochromator are of the order of 100μ and the sample size is one mm 2 . Hence it is essential to impart precision rotational and translational movements of the same order of magnitude to the mirrors with the use of appropriate mirror mounts. Since Indus-1 operates at a pressure -9 mbar, the mirror mounts should be UHV compatible and the movements should be actuated under UHV. The mirrors along with the mirror mounts are enclosed in UHV chambers. The mirror chambers have been fabricated at Centre for Advanced Technology (CAT) workshops and tested up to a pressure of 10 -9 mbar. The mirror mounts are designed, fabricated and leak checked (He leak rate -10 std cc/s) The precision movements are achieved with the help of bellow sealed shaft mechanism and adjustable screws provided with the kinematic mount of the mirror frame. The performance of the mirror mount was tested at atmospheric pressure by using a laser beam and found to be good. The minimum displacement of the laser beam at slit and sample positions is ∼ 70μ which is quite adequate for optical alignment. The performance of the mirror mount under UHV conditions is being evaluated. (author). 4 refs., 3 figs

  11. Controlling fugitive emissions from mechanical seals

    International Nuclear Information System (INIS)

    Adams, W.V.

    1992-01-01

    This paper reports that enactment of the 1990 Federal Clean Air Amendments will sharply focus efforts in the process industries to reduce fugitive emissions. Moreover, state and local governments may be imposing stricter laws and regulations which will affect allowable fugitive emissions from U.S. refineries and process plants. Plants outside the U.S. have similar concerns. Clearly, mechanical seals for process pumps represent an enormous population and is one category of equipment destined for careful evaluation as a means to control fugitive emissions. Fugitive are unintentional emissions from valves, pumps, flanges, compressors, etc., as opposed to point-source emissions from stacks, vents and flares. Fugitive emissions do not occur as a part of normal plant operations, but result from the effects of: Malfunctions, Age, Lack of proper maintenance, Operator error, Improper equipment specification, Use of inferior technology, and externally caused damage

  12. Aggregation and Photophysical Properties of Water-Soluble Sapphyrins

    Czech Academy of Sciences Publication Activity Database

    Kubát, Pavel; Lang, Kamil; Zelinger, Zdeněk; Král, V.

    2004-01-01

    Roč. 395, - (2004), s. 82-86 ISSN 0009-2614 R&D Projects: GA AV ČR KSK4040110 Keywords : water-soluble * sapphyrins * photophysical Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.438, year: 2004

  13. Electronic structures and photophysics of d8-d8 complexes

    Czech Academy of Sciences Publication Activity Database

    Gray, H. B.; Záliš, Stanislav; Vlček, Antonín

    2017-01-01

    Roč. 345, AUG 2017 (2017), s. 297-317 ISSN 0010-8545 R&D Projects: GA MŠk LH13015 Grant - others:COST(XE) CM1405 Institutional support: RVO:61388955 Keywords : excitation * electronic structures * photophysics Subject RIV: CG - Electrochemistry OBOR OECD: Physical chemistry Impact factor: 13.324, year: 2016

  14. Access control mechanism of wireless gateway based on open flow

    Science.gov (United States)

    Peng, Rong; Ding, Lei

    2017-08-01

    In order to realize the access control of wireless gateway and improve the access control of wireless gateway devices, an access control mechanism of SDN architecture which is based on Open vSwitch is proposed. The mechanism utilizes the features of the controller--centralized control and programmable. Controller send access control flow table based on the business logic. Open vSwitch helps achieve a specific access control strategy based on the flow table.

  15. Mechanical weed control in organic winter wheat

    Directory of Open Access Journals (Sweden)

    Euro Pannacci

    2017-12-01

    Full Text Available Three field experiments were carried out in organic winter wheat in three consecutive years (exp. 1, 2005-06; exp. 2, 2006- 07; exp. 3, 2007-08 in central Italy (42°57’ N - 12°22’ E, 165 m a.s.l. in order to evaluate the efficacy against weeds and the effects on winter wheat of two main mechanical weed control strategies: i spring tine harrowing used at three different application times (1 passage at T1, 2 passages at the time T1, 1 passage at T1 followed by 1 passage at T1 + 14 days in the crop sowed at narrow (traditional row spacing (0.15 m; and ii split-hoeing and finger-weeder, alone and combined at T1, in the crop sowed at wider row spacing (0.30 m. At the time T1 winter wheat was at tillering and weeds were at the cotyledons-2 true leaves growth stage. The experimental design was a randomized block with four replicates. Six weeks after mechanical treatments, weed ground cover (% was rated visually using the Braun-Blanquet coverabundance scale; weeds on three squares (0.6×0.5 m each one per plot were collected, counted, weighed, dried in oven at 105°C to determine weed density and weed above-ground dry biomass. At harvest, wheat ears density, grain yield, weight of 1000 seeds and hectolitre weight were recorded. Total weed flora was quite different in the three experiments. The main weed species were: Polygonum aviculare L. (exp. 1 and 2, Fallopia convolvulus (L. Á. Löve (exp. 1 and 3, Stachys annua (L. L. (exp. 1, Anagallis arvensis L. (exp. 2, Papaver rhoeas L. (exp.3, Veronica hederifolia L. (exp. 3. In the winter wheat sowed at narrow rows, 2 passages with spring-tine harrowing at the same time seems to be the best option in order to reconcile a good efficacy with the feasibility of treatment. In wider rows spacing the best weed control was obtained by split hoeing alone or combined with finger-weeder. The grain yield, on average 10% higher in narrow rows, the lower costs and the good selectivity of spring-tine harrowing

  16. Cellular Mechanisms of Ciliary Length Control

    Directory of Open Access Journals (Sweden)

    Jacob Keeling

    2016-01-01

    Full Text Available Cilia and flagella are evolutionarily conserved, membrane-bound, microtubule-based organelles on the surface of most eukaryotic cells. They play important roles in coordinating a variety of signaling pathways during growth, development, cell mobility, and tissue homeostasis. Defects in ciliary structure or function are associated with multiple human disorders called ciliopathies. These diseases affect diverse tissues, including, but not limited to the eyes, kidneys, brain, and lungs. Many processes must be coordinated simultaneously in order to initiate ciliogenesis. These include cell cycle, vesicular trafficking, and axonemal extension. Centrioles play a central role in both cell cycle progression and ciliogenesis, making the transition between basal bodies and mitotic spindle organizers integral to both processes. The maturation of centrioles involves a functional shift from cell division toward cilium nucleation which takes place concurrently with its migration and fusion to the plasma membrane. Several proteinaceous structures of the distal appendages in mother centrioles are required for this docking process. Ciliary assembly and maintenance requires a precise balance between two indispensable processes; so called assembly and disassembly. The interplay between them determines the length of the resulting cilia. These processes require a highly conserved transport system to provide the necessary substances at the tips of the cilia and to recycle ciliary turnover products to the base using a based microtubule intraflagellar transport (IFT system. In this review; we discuss the stages of ciliogenesis as well as mechanisms controlling the lengths of assembled cilia.

  17. Brain mechanisms that control sleep and waking

    Science.gov (United States)

    Siegel, Jerome

    This review paper presents a brief historical survey of the technological and early research that laid the groundwork for recent advances in sleep-waking research. A major advance in this field occurred shortly after the end of World War II with the discovery of the ascending reticular activating system (ARAS) as the neural source in the brain stem of the waking state. Subsequent research showed that the brain stem activating system produced cortical arousal via two pathways: a dorsal route through the thalamus and a ventral route through the hypothalamus and basal forebrain. The nuclei, pathways, and neurotransmitters that comprise the multiple components of these arousal systems are described. Sleep is now recognized as being composed of two very different states: rapid eye movements (REMs) sleep and non-REM sleep. The major findings on the neural mechanisms that control these two sleep states are presented. This review ends with a discussion of two current views on the function of sleep: to maintain the integrity of the immune system and to enhance memory consolidation.

  18. Photophysical properties of hexyl diethylaminohydroxybenzoylbenzoate (Uvinul A Plus), a UV-A absorber.

    Science.gov (United States)

    Shamoto, Yuta; Yagi, Mikio; Oguchi-Fujiyama, Nozomi; Miyazawa, Kazuyuki; Kikuchi, Azusa

    2017-09-13

    Hexyl diethylaminohydroxybenzoylbenzoate (DHHB, Uvinul A Plus) is a photostable UV-A absorber. The photophysical properties of DHHB have been studied by obtaining the transient absorption, total emission, phosphorescence and electron paramagnetic resonance spectra. DHHB exhibits an intense phosphorescence in a hydrogen-bonding solvent (e.g., ethanol) at 77 K, whereas it is weakly phosphorescent in a non-hydrogen-bonding solvent (e.g., 3-methylpentane). The triplet-triplet absorption and EPR spectra for the lowest excited triplet state of DHHB were observed in ethanol, while they were not observed in 3-methylpentane. These results are explained by the proposal that in the benzophenone derivatives possessing an intramolecular hydrogen bond, intramolecular proton transfer is an efficient mechanism of the very fast radiationless decay from the excited singlet state. The energy level of the lowest excited triplet state of DHHB is higher than those of the most widely used UV-B absorbers, octyl methoxycinnamate (OMC) and octocrylene (OCR). DHHB may act as a triplet energy donor for OMC and OCR in the mixtures of UV-A and UV-B absorbers. The bimolecular rate constant for the quenching of singlet oxygen by DHHB was determined by measuring the near-IR phosphorescence of singlet oxygen. The photophysical properties of diethylaminohydroxybenzoylbenzoic acid (DHBA) have been studied for comparison. It is a closely related building block to assist in interpreting the observed data.

  19. Physicochemical/photophysical characterization and angiogenic properties of Curcuma longa essential oil.

    Science.gov (United States)

    Araújo, Lilhian A; Araújo, Rafael G M; Gomes, Flávia O; Lemes, Susy R; Almeida, Luciane M; Maia, Lauro J Q; Gonçalves, Pablo J; Mrué, Fátima; Silva-Junior, Nelson J; Melo-Reis, Paulo R DE

    2016-01-01

    This study analyzed the physicochemical and photophysical properties of essential oil of Curcuma longa and its angiogenic potential. The results showed that curcumin is the main fluorescent component present in the oil, although the amount is relatively small. The experimental chorioallantoic membrane model was used to evaluate angiogenic activity, showing a significant increase in the vascular network of Curcuma longa and positive control groups when compared to the neutral and inhibitor controls (P Curcuma longa essential oil and the positive control (P >0.05). Histological analysis showed extensive neovascularization, hyperemia and inflammation in the positive control group and Curcuma longa when compared to other controls (P Curcuma longa oil showed considerable proangiogenic activity and could be a potential compound in medical applications.

  20. Control mechanisms for a nonlinear model of international relations

    Energy Technology Data Exchange (ETDEWEB)

    Pentek, A.; Kadtke, J. [Univ. of California, San Diego, La Jolla, CA (United States). Inst. for Pure and Applied Physical Sciences; Lenhart, S. [Univ. of Tennessee, Knoxville, TN (United States). Mathematics Dept.; Protopopescu, V. [Oak Ridge National Lab., TN (United States). Computer Science and Mathematics Div.

    1997-07-15

    Some issues of control in complex dynamical systems are considered. The authors discuss two control mechanisms, namely: a short range, reactive control based on the chaos control idea and a long-term strategic control based on an optimal control algorithm. They apply these control ideas to simple examples in a discrete nonlinear model of a multi-nation arms race.

  1. MAINTAINING VEHICLE SPEED USING A MECHANICAL CRUISE CONTROL

    Directory of Open Access Journals (Sweden)

    Peter GIROVSKÝ

    2017-06-01

    Full Text Available In this article we would like to present cruise control realization. This cruise control is presented as mechanical device for vehicle speed maintenance and has been proposed as a low cost solution. Principle of function in mechanical cruise control is based on a position control of throttle. For the right action of mechanical cruise control it was need to solve some particular tasks related with speed sensing, construct of device for control of throttle position and design of control system of whole mechanical cruise control. Information about car velocity we have gained using Hall sensor attached on a magnetic ring of car tachometer. For control of the throttle was used a small servo drive and as the control unit was used Arduino. The designed solution of mechanical cruise control have been realized for car Škoda Felicia.

  2. Physicochemical/photophysical characterization and angiogenic properties of Curcuma longa essential oil

    Directory of Open Access Journals (Sweden)

    LILHIAN A. ARAÚJO

    Full Text Available ABSTRACT This study analyzed the physicochemical and photophysical properties of essential oil of Curcuma longa and its angiogenic potential. The results showed that curcumin is the main fluorescent component present in the oil, although the amount is relatively small. The experimental chorioallantoic membrane model was used to evaluate angiogenic activity, showing a significant increase in the vascular network of Curcuma longa and positive control groups when compared to the neutral and inhibitor controls (P 0.05. Histological analysis showed extensive neovascularization, hyperemia and inflammation in the positive control group and Curcuma longa when compared to other controls (P <0.05, characteristic factors of the angiogenesis process. In conclusion, Curcuma longa oil showed considerable proangiogenic activity and could be a potential compound in medical applications.

  3. Group Theoretical Approach for Controlled Quantum Mechanical Systems

    National Research Council Canada - National Science Library

    Tarn, Tzyh-Jong

    2007-01-01

    The aim of this research is the study of controllability of quantum mechanical systems and feedback control of de-coherence in order to gain an insight on the structure of control of quantum systems...

  4. Control Mechanism and Security Region for Intentional Islanding Transition

    DEFF Research Database (Denmark)

    Chen, Yu; Xu, Zhao; Østergaard, Jacob

    2009-01-01

    in the grid. The concept of Islanding Security Region (ISR) has been proposed as an organic composition of the developed control mechanism. The purpose of this control mechanism is to maintain the frequency stability and eventually the security of power supply to the customers, by utilizing resources from...... generation and demand sides. The control mechanism can be extended to consider the distributed generations like wind power and other innovative technologies such as the Demand as Frequency controlled Reserve (DFR) technique in the future....

  5. Synthesis and photophysical characterizations of thermal-stable naphthalene benzimidazoles.

    Science.gov (United States)

    Erten-Ela, Sule; Ozcelik, Serdar; Eren, Esin

    2011-07-01

    Microwave-assisted synthesis, photophysical and electrochemical properties of thermal-stable naphthalene benzimidazoles and naphthalimides are studied in this paper. Microwave-assisted synthesis of naphthalene benzimidazoles provide higher yields than the conventional thermal synthesis. Comparative photophysical properties of naphthalene benzimidazoles and naphthalimides are revealed that conjugation of electron-donating group onto naphthalimide moiety increases fluorescence quantum yields. Fluorophore-solvent interactions are also investigated using Lippert-Mataga equation for naphthalimides and naphthalene benzimidazoles. Thermal stabilities of naphthalene benzimidazoles are better than naphthalimides due to increased aromaticity. The experimental E(LUMO) levels of naphthalene benzimidazoles are found to be between 3.15 and 3.28 eV. Therefore, naphthalene benzimidazole derivatives consisting of anchoring groups are promising materials in organic dye sensitized solar cells. © Springer Science+Business Media, LLC 2011

  6. Analysis and control of underactuated mechanical systems

    CERN Document Server

    Choukchou-Braham, Amal; Djemaï, Mohamed; Busawon, Krishna

    2014-01-01

    This monograph provides readers with tools for the analysis, and control of systems with fewer control inputs than degrees of freedom to be controlled, i.e., underactuated systems. The text deals with the consequences of a lack of a general theory that would allow methodical treatment of such systems and the ad hoc approach to control design that often results, imposing a level of organization whenever the latter is lacking. The authors take as their starting point the construction of a graphical characterization or control flow diagram reflecting the transmission of generalized forces through the degrees of freedom. Underactuated systems are classified according to the three main structures by which this is found to happen—chain, tree, and isolated vertex—and control design procedures proposed. The procedure is applied to several well-known examples of underactuated systems: acrobot; pendubot; Tora system; ball and beam; inertia wheel; and robotic arm with elastic joint. The text is illustrated with MATL...

  7. Robust Position Control of Electro-mechanical Systems

    OpenAIRE

    Rong Mei; Mou Chen

    2013-01-01

    In this work, the robust position control scheme is proposed for the electro-mechanical system using the disturbance observer and backstepping control method. To the external unknown load of the electro-mechanical system, the nonlinear disturbance observer is given to estimate the external unknown load. Combining the output of the developed nonlinear disturbance observer with backstepping technology, the robust position control scheme is proposed for the electro-mechanical system. The stabili...

  8. Towards a Unified Representation of Mechanisms for Robotic Control Software

    Directory of Open Access Journals (Sweden)

    Antonio Diaz-Calderon

    2008-11-01

    Full Text Available This article gives an overview of the Mechanism Model paradigm. The mechanism model paradigm provides a framework to modeling mechanisms for robotic control. The emphasis is on the unification of mathematical models of kinematics/dynamics, geometric information and control system parameters for a variety of robotic systems (including serial manipulators, wheeled and legged locomotors, with algorithms that are needed for typical robot control applications.

  9. Method of inspecting control rod drive mechanism

    International Nuclear Information System (INIS)

    Sato, Tomomi; Tatemichi, Shin-ichiro; Hasegawa, Hidenobu.

    1988-01-01

    Purpose: To conduct inspection for control rod drives and fuel handling operations in parallel without taking out the entire fuel, while maintaining the reactor in a subcritical state. Method: Control rod drives are inspected through the release of connection between control rods and control rod drives, detachment and dismantling of control rod drives, etc. In this case, structural materials having neutron absorbing power equal to or greater than the control rods are inserted into the gap after taking out fuels. Since the structural materials have neutron absorbing portion, subcriticality is maintained by the neutron absorbing effect. Accordingly, there is no requirement for taking out all of the fuels, thereby enabling to check the control rod drives and conduct handling for the fuels in parallel. As a result, the number of days required for the inspection can be shortened and it is possible to improve the working efficiency for the decomposition, inspection, etc. of the control rod drives and, thus, improve the operation efficiency of the nuclear power plant thereby attaining the predetermined purpose. (Kawakami, Y.)

  10. Cutaneous mechanisms of isometric ankle force control

    DEFF Research Database (Denmark)

    Choi, Julia T; Jensen, Jesper Lundbye; Leukel, Christian

    2013-01-01

    The sense of force is critical in the control of movement and posture. Multiple factors influence our perception of exerted force, including inputs from cutaneous afferents, muscle afferents and central commands. Here, we studied the influence of cutaneous feedback on the control of ankle force...... of transient stimulation on force error were greater when compared to continuous stimulation and lidocaine injection. Position-matching performance was unaffected by peroneal nerve or plantar nerve stimulation. Our results show that cutaneous feedback plays a role in the control of force output at the ankle...... joint. Understanding how the nervous system normally uses cutaneous feedback in motor control will help us identify which functional aspects are impaired in aging and neurological diseases....

  11. Oil pollution control mechanisms - statutes and regulations

    International Nuclear Information System (INIS)

    1978-04-01

    The purpose of this analysis is to provide a detailed picture of federal statutes and regulations, as well as case law, bearing on oil spill prevention and control. Emphasis has been placed on federal action occurring after a spill, although some effort is directed toward review of prevention statutes and regulations. In-depth consideration is given the control of oil pollution under the Federal Water Pollution Control Act but this analysis also touches lightly upon acts that have a lesser effect on oil pollution control. These acts being: The Refuse Act; The Ports and Waterways Safety Act of 1972; The Outer Continental Shelf Lands Act; The Oil Pollution Act of 1961; The Deepwater Port Act of 1974, and The Fish and Wildlife Coordination Act

  12. Photophysical properties of a surfactive long-chain styryl merocyanine dye as fluorescent probe

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, L.F.M., E-mail: Lailafmi@yahoo.com [Al-Azhar University, Faculty of Science, Chemistry Department, Nasr City, 12 Ibrahim El-Nagar, El-Hegaz Sq. Heliopolis, Cairo 11315 (Egypt)

    2012-09-15

    This work deals with detailed investigations of the photophysical properties of a styryl merocyanine dye, namely 1-cetyl-4-[4 Prime -(methoxy) styryl]-pyridinium bromide (CMSPB) of molecular rotor type. The solvatochromic analyses of the data in different solvents using the Kamlet-Taft parameters ({alpha}, {beta}, {pi}{sup Low-Asterisk }) were discussed. Optical excitation of the studied merocyanine dye populates a CT S{sub 1} state with about 22.64 folds higher dipole moment value relative to that in the S{sub 0} state. Moreover, the effect of solvent viscosity (glycerol at various temperatures (299.0-351.0 K)) on CMSPB fluorescent properties is analyzed to understand the molecular mechanisms of the characteristic increase in CMSPB fluorescence intensity. The results indicate that CMSPB exhibits fluorescent properties typical for molecular rotors. The results show that torsional relaxation dynamics of molecular rotors in high-viscosity solvents cannot be described by the simple stick boundary hydrodynamics defined by the Debye-Stokes-Einstein (DSE) equation. The fluorescence depolarization behavior in glycerol at various temperatures (299.0-351.0 K) shows that the molecular rotational diffusion is controlled by the free volume of the medium. Furthermore, excited state studies in ethanol/chloroform mixture revealed the formation of weak complex with chloroform of stoichiometry 1:1 with formation constant of 0.004l mol{sup -1}. Moreover, the increase of the quantum yield values in micellar solutions of CTAB and SDS relative to that of water indicates that the guest dye molecules are microencapsulated into the hydrophobic interior of host micelle. The obtained non-zero values of fluorescence polarization in micellar solution imply reduced rotational depolarization of dye molecules via association with the surfactant. Upon comparing the spectral data in micelles with those in homogeneous solvent systems, more can be learned of the structural details of the micellar

  13. Dynamics and control of hybrid mechanical systems

    NARCIS (Netherlands)

    Leonov, G.A.; Nijmeijer, H.; Pogromski, A.Y.; Fradkov, A.L.

    2010-01-01

    The papers in this edited volume aim to provide a better understanding of the dynamics and control of a large class of hybrid dynamical systems that are described by different models in different state space domains. They not only cover important aspects and tools for hybrid systems analysis and

  14. Parametric study of control mechanism of cortical bone remodeling under mechanical stimulus

    Science.gov (United States)

    Wang, Yanan; Qin, Qing-Hua

    2010-03-01

    The control mechanism of mechanical bone remodeling at cellular level was investigated by means of an extensive parametric study on a theoretical model described in this paper. From a perspective of control mechanism, it was found that there are several control mechanisms working simultaneously in bone remodeling which is a complex process. Typically, an extensive parametric study was carried out for investigating model parameter space related to cell differentiation and apoptosis which can describe the fundamental cell lineage behaviors. After analyzing all the combinations of 728 permutations in six model parameters, we have identified a small number of parameter combinations that can lead to physiologically realistic responses which are similar to theoretically idealized physiological responses. The results presented in the work enhanced our understanding on mechanical bone remodeling and the identified control mechanisms can help researchers to develop combined pharmacological-mechanical therapies to treat bone loss diseases such as osteoporosis.

  15. H∞ control of piezo actuated tilting mirror mechanism

    NARCIS (Netherlands)

    Van Dijk, J.

    2015-01-01

    In here the high bandwidth (2000 Hz.) feedback control of a precision mechanisms driven by a piezo actuator demanding a high absolute accuracy is discussed. The mechanism considered is rotating a mirror for laser bundle manipulation. It will be shown that a loopshaping controller design using the

  16. Mechanisms of Wnt signaling and control.

    Science.gov (United States)

    Grainger, Stephanie; Willert, Karl

    2018-03-30

    The Wnt signaling pathway is a highly conserved system that regulates complex biological processes across all metazoan species. At the cellular level, secreted Wnt proteins serve to break symmetry and provide cells with positional information that is critical to the patterning of the entire body plan. At the organismal level, Wnt signals are employed to orchestrate fundamental developmental processes, including the specification of the anterior-posterior body axis, induction of the primitive streak and ensuing gastrulation movements, and the generation of cell and tissue diversity. Wnt functions extend into adulthood where they regulate stem cell behavior, tissue homeostasis, and damage repair. Disruption of Wnt signaling activity during embryonic development or in adults results in a spectrum of abnormalities and diseases, including cancer. The molecular mechanisms that underlie the myriad of Wnt-regulated biological effects have been the subject of intense research for over three decades. This review is intended to summarize our current understanding of how Wnt signals are generated and interpreted. This article is categorized under: Biological Mechanisms > Cell Signaling Developmental Biology > Stem Cell Biology and Regeneration. © 2018 Wiley Periodicals, Inc.

  17. Control of Cellular Morphology by Mechanical Factors

    Science.gov (United States)

    Thoumine, Olivier

    1996-11-01

    This short review deals with the influence of mechanical factors on eucaryotic cell morphology and structure. We classify these factors into two types: i) external forces (e.g. gravitational forces or hemodynamic stresses), which when applied experimentally allow characterization of passive mechanical properties; and ii) internal forces, e.g. generated by molecular motors or polymerization processes. Perturbation of one or more of these forces induces significant changes in cell shape, cytoskeleton and pericellular matrix organization. We describe these phenomena in view of current models. Cette brève revue traite de l'influence des facteurs mécaniques sur la morphologie et la structure des cellules eucaryotes. Nous classifions ces facteurs en deux catégories : i) les forces externes (par exemple les forces de gravitation et les contraintes hèmodynamiques) qui, imposées in vitro, permettent de caractériser les propriétés mécaniques passives ; et ii) les forces internes, par exemple celles générées par les moteurs moléculaires ou les processus de polymérisation. La perturbation de l'une ou de l'autre de ces forces provoque des changements significatifs de la morphologie cellulaire ainsi que l'organisation du cytosquelette et de la matrice péricellulaire. Nous décrivons ces phénomènes en fonction de modèles existants.

  18. Frictionless segmented mechanics for controlled space closure

    OpenAIRE

    Andrade Jr, Ildeu

    2017-01-01

    ABSTRACT Extraction spaces may be needed to achieve specific orthodontic goals of positioning the dentition in harmony with the craniofacial complex. However, the fundamental reality that determines the occlusion final position is the control exerted by the orthodontist while closing the extraction spaces. A specific treatment objective may require the posterior teeth to remain in a constant position anteroposteriorly as well as vertically, while the anterior teeth occupy the entire extractio...

  19. An immunosurveillance mechanism controls cancer cell ploidy.

    Science.gov (United States)

    Senovilla, Laura; Vitale, Ilio; Martins, Isabelle; Tailler, Maximilien; Pailleret, Claire; Michaud, Mickaël; Galluzzi, Lorenzo; Adjemian, Sandy; Kepp, Oliver; Niso-Santano, Mireia; Shen, Shensi; Mariño, Guillermo; Criollo, Alfredo; Boilève, Alice; Job, Bastien; Ladoire, Sylvain; Ghiringhelli, François; Sistigu, Antonella; Yamazaki, Takahiro; Rello-Varona, Santiago; Locher, Clara; Poirier-Colame, Vichnou; Talbot, Monique; Valent, Alexander; Berardinelli, Francesco; Antoccia, Antonio; Ciccosanti, Fabiola; Fimia, Gian Maria; Piacentini, Mauro; Fueyo, Antonio; Messina, Nicole L; Li, Ming; Chan, Christopher J; Sigl, Verena; Pourcher, Guillaume; Ruckenstuhl, Christoph; Carmona-Gutierrez, Didac; Lazar, Vladimir; Penninger, Josef M; Madeo, Frank; López-Otín, Carlos; Smyth, Mark J; Zitvogel, Laurence; Castedo, Maria; Kroemer, Guido

    2012-09-28

    Cancer cells accommodate multiple genetic and epigenetic alterations that initially activate intrinsic (cell-autonomous) and extrinsic (immune-mediated) oncosuppressive mechanisms. Only once these barriers to oncogenesis have been overcome can malignant growth proceed unrestrained. Tetraploidization can contribute to oncogenesis because hyperploid cells are genomically unstable. We report that hyperploid cancer cells become immunogenic because of a constitutive endoplasmic reticulum stress response resulting in the aberrant cell surface exposure of calreticulin. Hyperploid, calreticulin-exposing cancer cells readily proliferated in immunodeficient mice and conserved their increased DNA content. In contrast, hyperploid cells injected into immunocompetent mice generated tumors only after a delay, and such tumors exhibited reduced DNA content, endoplasmic reticulum stress, and calreticulin exposure. Our results unveil an immunosurveillance system that imposes immunoselection against hyperploidy in carcinogen- and oncogene-induced cancers.

  20. Spectrally selective molecular doped solids: spectroscopy, photophysics and their application to ultrafast optical pulse processing

    International Nuclear Information System (INIS)

    Galaup, Jean-Pierre

    2005-01-01

    The persistent spectral hole-burning (PSHB) phenomenon observed in molecular doped polymers cooled down to liquid helium temperatures allows the engraving of spectral structures in the inhomogeneous absorption profile of the material. This phenomenon known since 1974 has became a fruitful field for the study of the intimacy of complex molecular systems in the solid state, revealing high-resolution spectroscopy, photophysics, photochemistry and dynamics of molecular doped amorphous media, organic as well as inorganic. A PSHB molecular doped solid can be programmed in spectral domain and therefore, it can be converted in an optical processor capable to achieve user-defined optical functions. Some aspects of this field are illustrated in the present paper. An application is presented where a naphthalocyanine doped polymer film is used in a demonstrative experiment to prove that temporal aberration free re-compression of ultra-short light pulses is feasible. Perspectives for the coherent control of light fields or photochemical processes are also evoked

  1. Bioherbicides: Current knowledge on weed control mechanism.

    Science.gov (United States)

    Radhakrishnan, Ramalingam; Alqarawi, Abdulaziz A; Abd Allah, Elsayed Fathi

    2018-04-17

    Weed control is a challenging event during crop cultivation. Integrated management, including the application of bioherbicides, is an emerging method for weed control in sustainable agriculture. Plant extracts, allelochemicals and some microbes are utilized as bioherbicides to control weed populations. Bioherbicides based on plants and microbes inhibit the germination and growth of weeds; however,few studies conducted in weed physiology. This review ascribes the current knowledge of the physiological changes in weeds that occur during the exposure to bioherbicides. Plant extracts or metabolites are absorbed by weed seeds, which initiates damage to the cell membrane, DNA, mitosis, amylase activity and other biochemical processes and delays or inhibits seed germination. The growth of weeds is also retarded due to low rates of root-cell division, nutrient uptake, photosynthetic pigment synthesis, and plant growth hormone synthesis, while the productions of reactive oxygen species (ROS) and stress-mediated hormones increase, including irregular antioxidant activity. However, lytic enzymes and toxic substances secreted from microbes degrade the weed seed coat and utilize the endosperm for survival, which inhibits seed germination. The microbes grow through the intercellular spaces to reach the root core, and the deposition of toxins in the cells affects cell division and cellular functions. Some of the metabolites of deleterious microbes cause disease, necrosis and chlorosis,which inhibit the germination and growth of weed seeds by suppressing photosynthesis and gibberellin activities and enhancing ROS, abscisic acid and ethylene. This review explains the effects of bioherbicides (derived from plants and microbes) on weed-plant physiology to elucidate their modes of action. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Two Mechanisms to Avoid Control Conflicts Resulting from Uncoordinated Intent

    Science.gov (United States)

    Mishkin, Andrew H.; Dvorak, Daniel L.; Wagner, David A.; Bennett, Matthew B.

    2013-01-01

    This software implements a real-time access control protocol that is intended to make all connected users aware of the presence of other connected users, and which of them is currently in control of the system. Here, "in control" means that a single user is authorized and enabled to issue instructions to the system. The software The software also implements a goal scheduling mechanism that can detect situations where plans for the operation of a target system proposed by different users overlap and interact in conflicting ways. In such situations, the system can either simply report the conflict (rejecting one goal or the entire plan), or reschedule the goals in a way that does not conflict. The access control mechanism (and associated control protocol) is unique. Other access control mechanisms are generally intended to authenticate users, or exclude unauthorized access. This software does neither, and would likely depend on having some other mechanism to support those requirements.

  3. Photophysics of aggregated 9-methylthiacarbocyanine bound to polyanions

    Science.gov (United States)

    Chibisov, Alexander K.; Görner, Helmut

    2002-05-01

    The photophysical properties of 3,3 '-diethyl-9-methylthiacarbocyanine (DTC) were studied in the presence of polystyrene sulfonate (PSS), polyacrylic acid (PAA) and polymethacrylic acid (PMA). The absorption spectra reflect a monomer/dimer equilibrium in neat aqueous solution and a shift towards bound H-aggregates, bound dimers and bound monomers on increasing the ratio of polyanion residue to dye concentrations ( r). These equilibria also determine the photodeactivation modes of DTC. The fluorescence intensity is reduced, when dimers and aggregates are present and strongly enhanced for low dye loading ( r=10 4). In contrast, the quantum yield of intersystem crossing is enhanced for bound dimers ( r=10 3).

  4. Photophysical study of a cyclophane displaying intramolecular exciplex emission

    International Nuclear Information System (INIS)

    Galindo, Francisco; Isabel Burguete, M.; Luis, Santiago V.

    2004-01-01

    The photophysical behavior of cyclophane 1, comprised by two L-valine units and one naphthalene ring, has been studied. It displays exciplex (EX) emission with a maximum in the range 390-460 nm, depending on solvent polarity. From this dependence a dipole moment of 19.4 D for the excited charge-transfer state has been calculated. Fluorescence quantum yields in organic media ranging from 0.012 to 0.038 have been measured. This phenomenon has been interpreted taking into account the rigidity imposed by the cyclophane framework which could pre-orient the donor and the acceptor subunits for a favorable interaction

  5. Photophysical study of a cyclophane displaying intramolecular exciplex emission

    Energy Technology Data Exchange (ETDEWEB)

    Galindo, Francisco; Isabel Burguete, M.; Luis, Santiago V

    2004-07-12

    The photophysical behavior of cyclophane 1, comprised by two L-valine units and one naphthalene ring, has been studied. It displays exciplex (EX) emission with a maximum in the range 390-460 nm, depending on solvent polarity. From this dependence a dipole moment of 19.4 D for the excited charge-transfer state has been calculated. Fluorescence quantum yields in organic media ranging from 0.012 to 0.038 have been measured. This phenomenon has been interpreted taking into account the rigidity imposed by the cyclophane framework which could pre-orient the donor and the acceptor subunits for a favorable interaction.

  6. Neural Control Mechanisms and Body Fluid Homeostasis

    Science.gov (United States)

    Johnson, Alan Kim

    1998-01-01

    The goal of the proposed research was to study the nature of afferent signals to the brain that reflect the status of body fluid balance and to investigate the central neural mechanisms that process this information for the activation of response systems which restore body fluid homeostasis. That is, in the face of loss of fluids from intracellular or extracellular fluid compartments, animals seek and ingest water and ionic solutions (particularly Na(+) solutions) to restore the intracellular and extracellular spaces. Over recent years, our laboratory has generated a substantial body of information indicating that: (1) a fall in systemic arterial pressure facilitates the ingestion of rehydrating solutions and (2) that the actions of brain amine systems (e.g., norepinephrine; serotonin) are critical for precise correction of fluid losses. Because both acute and chronic dehydration are associated with physiological stresses, such as exercise and sustained exposure to microgravity, the present research will aid in achieving a better understanding of how vital information is handled by the nervous system for maintenance of the body's fluid matrix which is critical for health and well-being.

  7. Mechanisms controlling radionuclide mobility in forest soils

    International Nuclear Information System (INIS)

    Delvaux, B.; Kruyts, N.; Maes, E.; Agapkina, G.I.; Kliashtorin, A.; Bunzl, K.; Rafferty, B.

    1996-01-01

    Soil processes strongly influence the radionuclide mobility in soils. The mobility of radionuclides in forest soils is governed by several processes involving both abiotic and biotic factors. The sorption-desorption process chiefly governs the activity of radionuclides in the soil solution, hence thereby their mobility and biological availability. Radiocaesium exhibits a very low mobility in mineral soils. Both mobility and bioavailability however increase as the thickness of organic layers and their content in organic matter increases. Clay minerals of micaceous origin strongly act as slinks for radiocaesium in forest soils. The magnitude of cesium mineral fixation in topsoils is expected to be the highest in mineral soils of Eutric cambisol type, and, to a lesser extent, of type of Distric cambisol and Podzoluvisol. A low mobility of radiocaesium in the surface horizons of forest soils may also be partially explained by a biological mobilization: fungi absorb radiocaesium and transport it to upper layers, thereby contributing to constantly recycle the radioelement in the organic horizons. This mechanism is probably important in soils with thick organic layers (Podsol, Histosol, and, to a lesser extent, Distric cambisol and Podzoluvisol). Radionuclides can be associated with soluble organic anions in the soil solution of forest acid soils. Such associations are highly mobile: they are stable in conditions of poor biological activity (low temperatures, acid soil infertility, water excess, etc.). Their magnitude is expected to be the highest in thick acid organic layers (soils of type Podzol and Histosol)

  8. Urgent epidemic control mechanism for aviation networks

    KAUST Repository

    Peng, Chengbin; Wang, Shengbin; Shi, Meixia; Jin, Xiaogang

    2011-01-01

    In the current century, the highly developed transportation system can not only boost the economy, but also greatly accelerate the spreading of epidemics. While some epidemic diseases may infect quite a number of people ahead of our awareness, the health care resources such as vaccines and the medical staff are usually locally or even globally insufficient. In this research, with the network of major aviation routes as an example, we present a method to determine the optimal locations to allocate the medical service in order to minimize the impact of the infectious disease with limited resources. Specifically, we demonstrate that when the medical resources are insufficient, we should concentrate our efforts on the travelers with the objective of effectively controlling the spreading rate of the epidemic diseases. © 2011 Springer-Verlag Berlin Heidelberg.

  9. Chemical mechanisms in mercury emission control technologies

    Energy Technology Data Exchange (ETDEWEB)

    Olson, E.S.; Laumb, J.D.; Benson, S.A.; Dunham, G.E.; Sharma, R.K.; Mibeck, B.A.; Miller, S.J.; Holmes, M.J.; Pavlish, J.H. [University of North Dakota, Energy and Environmental Research Center, Grand Forks, ND (United States)

    2003-05-01

    The emission of elemental mercury in the flue gas from coal-burning power plants is a major environmental concern. Control technologies utilizing activated carbon show promise and are currently under intense review. Oxidation and capture of elemental mercury on activated carbon was extensively investigated in a variety of flue gas atmospheres. Extensive parametric testing with individual and a variety of combinations and concentrations of reactive flue gas components and spectroscopic examination of the sulfur and chlorine forms present before and after breakthrough have led to an improved model to explain the kinetic and capacity results. The improved model delineates the independent Lewis acid oxidation site as well as a zig-zag carbene site on the carbon edge that performs as a Lewis base in reacting with both the oxidized mercury formed at the oxidation site and with the acidic flue gas components in competing reactions to form organochlorine, sulfinate, and sulfate ester moieties on the carbon edge.

  10. Installing and detaching apparatus for a control rod drive mechanism

    International Nuclear Information System (INIS)

    Akimoto, Seiichi; Watanabe, Mitsuhiro; Yoshida, Tomiharu; Sugaya, Jun-ichi; Saito, Takashi.

    1976-01-01

    Object: To facilitate maintenance and repair of a control rod drive mechanism. Structure: The apparatus comprises a means moving in a moving direction of a control rod within a reactor vessel, said moving means having a housing mounted thereon, a means mounted on the reactor vessel to release a connection between a control rod drive mechanism connected to the control rod and the control rod, and a means for mounting and removing a fixing means which connects the reactor vessel to the control rod drive means. With this arrangement, cooling water of high radioactivity level may not be leaked outside to thereby notably reduce dangerousness of exposure and materially cut time required for mounting and removing the control rod drive mechanism. (Ohara, T.)

  11. Controlling chaos based on an adaptive adjustment mechanism

    International Nuclear Information System (INIS)

    Zheng Yongai

    2006-01-01

    In this paper, we extend the ideas and techniques developed by Huang [Huang W. Stabilizing nonlinear dynamical systems by an adaptive adjustment mechanism. Phys Rev E 2000;61:R1012-5] for controlling discrete-time chaotic system using adaptive adjustment mechanism to continuous-time chaotic system. Two control approaches, namely adaptive adjustment mechanism (AAM) and modified adaptive adjustment mechanism (MAAM), are investigated. In both case sufficient conditions for the stabilization of chaotic systems are given analytically. The simulation results on Chen chaotic system have verified the effectiveness of the proposed techniques

  12. Manual, mechanical, and cultural control methds and tools

    Science.gov (United States)

    Steven Manning; James. Miller

    2011-01-01

    There are many land management scenarios where chemicals are not the ideal choice for controlling invasive plants. More often than not, the best approach is the use of integrated pest management involving a variety of control methods. Maximizing the value of mechanical, manual, and cultural control methods with the added benefit of selective herbicides can offer the...

  13. Mechanical design and control of a new myoelectric hand prosthesis

    NARCIS (Netherlands)

    Peerdeman, B.; Stramigioli, Stefano; Hekman, Edsko E.G.; Brouwer, Dannis Michel; Misra, Sarthak

    2011-01-01

    The development of modern, myoelectrically controlled hand prostheses can be difficult, due to the many requirements its mechanical design and control system need to fulfill [1]. The hand should be controllable with few input signals, while being able to perform a wide range of motions. It should be

  14. The Effect of Headquarter Integration Mechanisms on Subsidiaries’ New Product Success: From Control to Coordination Mechanism

    Directory of Open Access Journals (Sweden)

    Firmanzah Firmanzah

    2013-07-01

    Full Text Available New product launching (NPL to the local market by subsidiary managers is a strategic activity, which requires organizational supports from MNC global network. The NPL activity is marked by high level of uncertainty, risk, and market failure. Thus, a headquarter needs to integrate the subsidiary NPL into global strategy. There are two mechanisms to integrate subsidiaries’ activities during NPL process; coordination and control process. By testing the effect of each mechanism on role clarity and functional conflict, I found that coordination mechanism increase role clarity between headquarter and subsidiaries’ managers. In contrast, exercising control mechanism reduces role clarity and functional conflict between headquarter and subsidiaries’ managers during NPL. This research shows that both role clarity and functional conflict increase new product commercial performance introduced by subsidiary in the local market. Keywords: new product launching (NPL, coordination mechanism, control mechanism, and new product performance

  15. Ionization photophysics and Rydberg spectroscopy of diacetylene

    KAUST Repository

    Schwell, Martin; Bé nilan, Yves; Fray, Nicolas; Gazeau, Marie Claire; Es-sebbar, Et-touhami; Gaie-Levrel, Franç ois; Champion, Norbert; Leach, Sydney Sydney

    2012-01-01

    Photoionization of diacetylene was studied using synchrotron radiation over the range 8-24 eV, with photoelectron-photoion coincidence (PEPICO) and threshold photoelectron-photoion coincidence (TPEPICO) techniques. Mass spectra, ion yields, total and partial ionization cross-sections were measured. The adiabatic ionization energy of diacetylene was determined as IE ad=(10.17±0.01) eV, and the appearance energy of the principal fragment ion C4H+ as AE=(16.15±0.03) eV. Calculated appearance energies of other fragment ions were used to infer aspects of dissociation pathways forming the weaker fragment ions C+ 4, C3H+, C+3 and C 4H+. Structured autoionization features observed in the PEPICO spectrum of diacetylene in the 11-13 eV region were assigned to vibrational components of three new Rydberg series, R1(nsσg, n=4-11), R2(ndσg, n=4-7) and R3(ndδg, n=4-6) converging to the A2Πu state of the cation, and to a new series R01(nsσg, n=3) converging to the B' 2Σ+u state of the cation. The autoionization mechanisms and their consistence with specific selection rules are discussed. © 2012 Taylor and Francis.

  16. Ionization photophysics and Rydberg spectroscopy of diacetylene

    KAUST Repository

    Schwell, Martin

    2012-11-01

    Photoionization of diacetylene was studied using synchrotron radiation over the range 8-24 eV, with photoelectron-photoion coincidence (PEPICO) and threshold photoelectron-photoion coincidence (TPEPICO) techniques. Mass spectra, ion yields, total and partial ionization cross-sections were measured. The adiabatic ionization energy of diacetylene was determined as IE ad=(10.17±0.01) eV, and the appearance energy of the principal fragment ion C4H+ as AE=(16.15±0.03) eV. Calculated appearance energies of other fragment ions were used to infer aspects of dissociation pathways forming the weaker fragment ions C+ 4, C3H+, C+3 and C 4H+. Structured autoionization features observed in the PEPICO spectrum of diacetylene in the 11-13 eV region were assigned to vibrational components of three new Rydberg series, R1(nsσg, n=4-11), R2(ndσg, n=4-7) and R3(ndδg, n=4-6) converging to the A2Πu state of the cation, and to a new series R01(nsσg, n=3) converging to the B\\' 2Σ+u state of the cation. The autoionization mechanisms and their consistence with specific selection rules are discussed. © 2012 Taylor and Francis.

  17. Photophysics of Carbon Nanotubes Interfaced with Organic and Inorganic Materials

    CERN Document Server

    Levitsky, Igor A; Karachevtsev, Victor A

    2012-01-01

    Photophysics of Carbon Nanotubes Interfaced with Organic and Inorganic Materials describes physical, optical and spectroscopic properties of the emerging class of nanocomposites formed from carbon nanotubes (CNTs)  interfacing with organic and inorganic materials. The three main chapters detail novel trends in  photophysics related to the interaction of  light with various carbon nanotube composites from relatively simple CNT/small molecule assemblies to complex hybrids such as CNT/Si and CNT/DNA nanostructures.   The latest experimental results are followed up with detailed discussions and scientific and technological perspectives to provide a through coverage of major topics including: ·   Light harvesting, energy conversion, photoinduced charge separation  and transport  in CNT based nanohybrids · CNT/polymer composites exhibiting photoactuation; and ·         Optical  spectroscopy  and structure of CNT/DNA complexes. Including original data and a short review of recent research, Phot...

  18. Mechanical systems a unified approach to vibrations and controls

    CERN Document Server

    Gans, Roger F

    2015-01-01

    This essential textbook covers analysis and control of engineering mechanisms, which include almost any apparatus with moving parts used in daily life, from musical instruments to robots. The text  presents both vibrations and controls with considerable breadth and depth using a unified notation. It strikes a nice balance between the analytical and the practical.  This text contains enough material for a two semester sequence, but it can also be used in a single semester course combining the two topics. Mechanical Systems: A Unified Approach to Vibrations and Controls presents a common notation and approach to these closely related areas. Examples from the both vibrations and controls components are integrated throughout this text. This book also: ·         Presents a unified approach to vibrations and controls, including an excellent diagram that simultaneously discusses embedding classical vibrations (mechanical systems) in a discussion of models, inverse models, and open and closed loop control ...

  19. Control of a mechanical gripper with a fuzzy controller; Control de una garra robotizada mediante un controlador borroso

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, J.; Barcala, J.M.; Gamero, E.; Navarrete, J.J.

    1995-07-01

    A fuzzy logic system is used to control a mechanical gripper. System is based in a NLX230 fuzzy micro controller. Control rules are programmed by a 68020 microprocessor in the micro controller memory. Stress and its derived are used as feedback signals in the control. This system can adapt its effort to the mechanical resistance of the object between the fingers.

  20. Control of a mechanical gripper with a fuzzy controller; Control de una garra robotizada mediante un controlador borroso

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, J.; Barcala, J.M.; Gamero, E.; Navarrete, J.J.

    1995-07-01

    A fuzzy logic system is used to control a mechanical gripper. System is based in a NLX230 fuzzy micro controller. Control rules are programmed by a 68020 microprocessor in the micro controller memory. Stress and its derived are used as feedback signals in the control. This system can adapt its effort to the mechanical resistance of the object between the fingers. (Author)

  1. The Design of Wheelchair Lifting Mechanism and Control System

    Institute of Scientific and Technical Information of China (English)

    ZHAO Cong; WANG Zheng-xing; JIANG Shi-hong; ZHANG Li; LIU Zheng-yu

    2014-01-01

    In order to achieve a wheelchair lift function, this paper designs a tri-scissors mechanism. Through the so-called H-type transmission and L-type swing rod, the three scissors mechanisms lift in the same rate with only one liner motor while ensuring the stability of the lift. Finite element analysis in ANSYS is performed to verify the material strength. The control system with Sunplus SCM achieves the voice control of wheelchair walking and lifting.

  2. Cyclic movement pin mechanism for controlling a nuclear reactor

    International Nuclear Information System (INIS)

    Joly, J.G.; Martin, Jean.

    1981-01-01

    This invention concerns a recurring movement pin mechanism for controlling a nuclear reactor by shifting a neutron absorbing assembly, vertically mobile in the nuclear reactor, to adjust the power and for emergency shut-down. This mechanism ensures a continuous movement and accurate shut-down at any level of the travel height of the absorbing assembly in the core. It also prevents the impacts of the pivoting pins in the control rod slots [fr

  3. Mechanics and model-based control of advanced engineering systems

    CERN Document Server

    Irschik, Hans; Krommer, Michael

    2014-01-01

    Mechanics and Model-Based Control of Advanced Engineering Systems collects 32 contributions presented at the International Workshop on Advanced Dynamics and Model Based Control of Structures and Machines, which took place in St. Petersburg, Russia in July 2012. The workshop continued a series of international workshops, which started with a Japan-Austria Joint Workshop on Mechanics and Model Based Control of Smart Materials and Structures and a Russia-Austria Joint Workshop on Advanced Dynamics and Model Based Control of Structures and Machines. In the present volume, 10 full-length papers based on presentations from Russia, 9 from Austria, 8 from Japan, 3 from Italy, one from Germany and one from Taiwan are included, which represent the state of the art in the field of mechanics and model based control, with particular emphasis on the application of advanced structures and machines.

  4. Energy analysis of control rod drive mechanism in HTR-10

    International Nuclear Information System (INIS)

    Bo Hanliang; Wu Yuanqiang

    2000-01-01

    This paper presents a theoretical model for the control rod drive mechanism for the 10 MW High Temperature Gas Cooled Reactor (HTR-10) and analyzes accidents which may occur in the drive mechanism, for example, chain break, coupling damage and other damage scenarios. The results show that the matching problem between buffer capability and coupling strength is the main reason for coupling damage; increased temperatures would reduce eddy damping and cause a mismatch between buffer capability and coupling strength; and the displacement of the buffer spring will affect the coupling force. The results provide a theoretical basis for the design of the control rod drive mechanism for HTR-10

  5. Non-destructive controls in the mechanical industry

    Energy Technology Data Exchange (ETDEWEB)

    Jarlan, L

    1978-12-01

    The sequence of operations implicating the mechanical industries from the suppliers to their customers is briefly recalled; a description of the field of application of non-destructive control methods in these industries is given. Follows a description of some recent typical applications of the principal methods: radiography, ultrasonic waves, magnetism, acoustic emission, sonic control, tracer techniques.

  6. Soft Time-Suboptimal Controlling Structure for Mechanical Systems

    DEFF Research Database (Denmark)

    Kulczycki, Piotr; Wisniewski, Rafal; Kowalski, Piotr

    2004-01-01

    The paper presents conception of a soft control structure based on the time-optimal approach. Its parameters are selected in accordance with the rules of the statistical decision theory and additionally it allows to eliminate rapid changes in control values. The object is a basic mechanical system......, with uncertain (also non-stationary) mass treated as a stochastic process. The methodology proposed here is of a universal nature and may easily be applied with respect to other uncertainty elements of timeoptimal controlled mechanical systems....

  7. Monolithic Controlled Delivery Systems: Part I. Basic Characteristics and Mechanisms

    Directory of Open Access Journals (Sweden)

    Rumiana Blagoeva

    2006-04-01

    Full Text Available The article considers contemporary systems for controlled delivery of active agents, such as drugs, agricultural chemicals, pollutants and additives in the environment. A useful classification of the available controlled release systems (CRS is proposed according to the type of control (passive, active or self-preprogrammed and according to the main controlling mechanism (diffusion, swelling, dissolution or erosion. Special attention is given to some of the most used CRS - polymer monoliths. The structural and physical-chemical characteristics of CRS as well as the basic approaches to their production are examined. The basic mechanisms of controlled agent release are reviewed in detail and factors influencing the release kinetics are classified according to their importance. The present study can be helpful for understanding and applying the available mathematical models and for developing more comprehensive ones intended for design of new controlled delivery systems.

  8. New dimensions in mechanical plaque control: An overview

    Directory of Open Access Journals (Sweden)

    Arnab Mandal

    2017-01-01

    Full Text Available Plaque control is the daily removal of dental plaque, oral biofilm and also prevention of their accumulation on the teeth and other parts of oral cavity. Dental plaque is the major etiology of maximum gingival and periodontal diseases. It is also related with various dental problems. Mechanical plaque control is a very effective method to get rid of plaque accumulation in oral cavity. In 3000 BC there was the first toothbrush invented by human beings. With time several modifications came in toothbrushes to make mechanical plaque control more effective in day to day oral hygiene practice. This article emphasizes on the advanced and emerging tools in mechanical plaque control methods in attaining an optimal level of oral hygiene standards and maintenance of oral health.

  9. Mechanisms that control aqueous leaching of nuclear waste glass

    International Nuclear Information System (INIS)

    Simmons, J.H.; Barkatt, A.; Macedo, P.B.

    1982-01-01

    The development of predictive models and risk calculations for the time evolution of radioactive isotope leaching from fixation solids depends on many factors, including measurement accuracy, measurement relevance, a complete understanding of possible dissolution mechanisms, and the ability to project worst case conditions for all appropriate mechanisms. Some of the mechanisms observed and understood at present are the mechanisms of dissolution of glasses in neutral unbuffered water, the effects of structural disintegration of the glass protective layer, the effects of slowly flowing bath waters and possibly, the mechanisms of leach-rate reduction by solution saturation. The mechanisms that control radiation and temperature effects including alpha particle emission and nuclear transmutations are as yet little understood or investigated

  10. Photophysics of charge transfer in a polyfluorene/violanthrone blend

    Science.gov (United States)

    Cabanillas-Gonzalez, J.; Virgili, T.; Lanzani, G.; Yeates, S.; Ariu, M.; Nelson, J.; Bradley, D. D. C.

    2005-01-01

    We present a study of the photophysical and photovoltaic properties of blends of violanthrone in poly[9, 9-bis (2-ethylhexyl)-fluorene-2, 7-diyl ] (PF2/6) . Photoluminescence quenching and photocurrent measurements show moderate efficiencies for charge generation, characteristic of such polymer/dye blends. Pump-probe measurements on blend films suggest that while ˜47% of the total exciton population dissociates within 4ps of photoexcitation, only ˜32% subsequently results in the formation of dye anions. We attribute the discrepancy to the likely formation of complex species with long lifetimes, such as stabilized interface charge pairs or exciplexes. This conclusion is supported by the appearance of a long lifetime component of 2.4ns in the dynamics of the photoinduced absorption signal associated to polarons in photoinduced absorption bands centered at 560nm .

  11. Naphthalene-based fluorophores: Synthesis characterization, and photophysical properties

    International Nuclear Information System (INIS)

    Feng Jinwu; Chen Xiaopeng; Han Qingchuan; Wang Hongbo; Lu Ping; Wang Yanguang

    2011-01-01

    U-type, 1,8-diarylnaphthalenes and 1,8-diarylethynylnaphthalenes were synthesized and their structures were characterized by spectroscopic methods. Emission performance of these compounds with donor and acceptor was largely depended upon the solvent polarity and environmental acidity, which implied that they might be used as solvent polarity sensors or pH sensors as well. Moreover, some 1,8-diarylnaphthalenes exhibited aggregation-induced emission enhancement (AIEE) based on their photophysical investigation and might be used as light emitting materials for optoelectronic applications. - Highlights: → 1,8-Diarylnaphthalenes and 1,8-diarylethynylnaphthalenes were synthesized. → Emission of these compounds depended on solvent polarity and environmental acidity. → Some 1,8-diarylnaphthalenes exhibited aggregation-induced emission enhancement.

  12. Bibliographic study of photophysical and photochemical properties of laser dyes

    International Nuclear Information System (INIS)

    Doizi, D.

    1986-06-01

    Laser isotope separation of uranium requires high power and precise wave length. This report is a bibliographic and experimental study of the photophysical and photochemical properties of seven commercial laser dyes which have an emission wavelength in the range 5500-6500 A: Rhodamine 110 or 560, rhodamine 6G or 590, rhodamine B or 610, rhodamine 101 or 640, sulforhodamine B or kiton red 620, sulforhodamine 101 or 640 and DCM or LC 6500. Absorption and emission cross section values, fluorescence lifetimes and quantum yields in various solvents are indicated. For each dye, a non exhaustive list of laboratory experiments made with two types of pump sources: Nd YAG (532) and copper vapor laser is given. When it is known, the toxicity of the dyes is mentioned [fr

  13. The JPL telerobotic Manipulator Control and Mechanization (MCM) subsystem

    Science.gov (United States)

    Hayati, Samad; Lee, Thomas S.; Tso, Kam; Backes, Paul; Kan, Edwin; Lloyd, J.

    1989-01-01

    The Manipulator Control and Mechanization (MCM) subsystem of the telerobot system provides the real-time control of the robot manipulators in autonomous and teleoperated modes and real time input/output for a variety of sensors and actuators. Substantial hardware and software are included in this subsystem which interfaces in the hierarchy of the telerobot system with the other subsystems. The other subsystems are: run time control, task planning and reasoning, sensing and perception, and operator control subsystem. The architecture of the MCM subsystem, its capabilities, and details of various hardware and software elements are described. Important improvements in the MCM subsystem over the first version are: dual arm coordinated trajectory generation and control, addition of integrated teleoperation, shared control capability, replacement of the ultimate controllers with motor controllers, and substantial increase in real time processing capability.

  14. Pyridine-Based Conjugated Polymers: Photophysical Properties and Light- Emitting Diodes

    National Research Council Canada - National Science Library

    Epstein, A

    1997-01-01

    We study the photophysical properties of the pyridine-based polymers poly (p-pyridyl vinylene) (PPyV) and poly (p-pyridine) (PPy). The primary photoexcitations in the pyridine-based polymers are singlet excitons...

  15. Photophysics of Organic-Inorganic Hybrid Lead Iodide Perovskite Single Crystals

    NARCIS (Netherlands)

    Fang, Honghua; Raissa, Raissa; Abdu-Aguye, Mustapha; Adjokatse, Sampson; Blake, Graeme R.; Even, Jacky; Loi, Maria Antonietta

    2015-01-01

    Hybrid organometal halide perovskites have been demonstrated to have outstanding performance as semiconductors for solar energy conversion. Further improvement of the efficiency and stability of these devices requires a deeper understanding of their intrinsic photophysical properties. Here, the

  16. Control mechanism of double-rotator-structure ternary optical computer

    Science.gov (United States)

    Kai, SONG; Liping, YAN

    2017-03-01

    Double-rotator-structure ternary optical processor (DRSTOP) has two characteristics, namely, giant data-bits parallel computing and reconfigurable processor, which can handle thousands of data bits in parallel, and can run much faster than computers and other optical computer systems so far. In order to put DRSTOP into practical application, this paper established a series of methods, namely, task classification method, data-bits allocation method, control information generation method, control information formatting and sending method, and decoded results obtaining method and so on. These methods form the control mechanism of DRSTOP. This control mechanism makes DRSTOP become an automated computing platform. Compared with the traditional calculation tools, DRSTOP computing platform can ease the contradiction between high energy consumption and big data computing due to greatly reducing the cost of communications and I/O. Finally, the paper designed a set of experiments for DRSTOP control mechanism to verify its feasibility and correctness. Experimental results showed that the control mechanism is correct, feasible and efficient.

  17. Intra- and Intercellular Quality Control Mechanisms of Mitochondria

    Directory of Open Access Journals (Sweden)

    Yoshimitsu Kiriyama

    2017-12-01

    Full Text Available Mitochondria function to generate ATP and also play important roles in cellular homeostasis, signaling, apoptosis, autophagy, and metabolism. The loss of mitochondrial function results in cell death and various types of diseases. Therefore, quality control of mitochondria via intra- and intercellular pathways is crucial. Intracellular quality control consists of biogenesis, fusion and fission, and degradation of mitochondria in the cell, whereas intercellular quality control involves tunneling nanotubes and extracellular vesicles. In this review, we outline the current knowledge on the intra- and intercellular quality control mechanisms of mitochondria.

  18. Quantum control mechanism analysis through field based Hamiltonian encoding

    International Nuclear Information System (INIS)

    Mitra, Abhra; Rabitz, Herschel

    2006-01-01

    Optimal control of quantum dynamics in the laboratory is proving to be increasingly successful. The control fields can be complex, and the mechanisms by which they operate have often remained obscure. Hamiltonian encoding (HE) has been proposed as a method for understanding mechanisms in quantum dynamics. In this context mechanism is defined in terms of the dominant quantum pathways leading to the final state of the controlled system. HE operates by encoding a special modulation into the Hamiltonian and decoding its signature in the dynamics to determine the dominant pathway amplitudes. Earlier work encoded the modulation directly into the Hamiltonian operators. This present work introduces the alternative scheme of field based HE, where the modulation is encoded into the control field and not directly into the Hamiltonian operators. This distinct form of modulation yields a new perspective on mechanism and is computationally faster than the earlier approach. Field based encoding is also an important step towards a laboratory based algorithm for HE as it is the only form of encoding that may be experimentally executed. HE is also extended to cover systems with noise and uncertainty and finally, a hierarchical algorithm is introduced to reveal mechanism in a stepwise fashion of ever increasing detail as desired. This new hierarchical algorithm is an improvement over earlier approaches to HE where the entire mechanism was determined in one stroke. The improvement comes from the use of less complex modulation schemes, which leads to fewer evaluations of Schroedinger's equation. A number of simulations are presented on simple systems to illustrate the new field based encoding technique for mechanism assessment

  19. The Effect of Headquarter Integration Mechanisms on Subsidiaries’ New Product Success: From Control to Coordination Mechanism

    Directory of Open Access Journals (Sweden)

    Firmanzah

    2007-10-01

    Full Text Available New product launching (NPL to the local market by subsidiary managers is a strategic activity, which requires organizational supports from MNC global network. The NPL activity is marked by high level of uncertainty, risk, and market failure. Thus, a headquarter needs to integrate the subsidiary NPL into global strategy. There are two mechanisms to integrate subsidiaries’ activities during NPL process; coordination and control process. By testing the effect of each mechanism on role clarity and functional conflict, I found that coordination mechanism increase role clarity between headquarter and subsidiaries’ managers. In contrast, exercising control mechanism reduces role clarity and functional conflict between headquarter and subsidiaries’ managers during NPL. This research shows that both role clarity and functional conflict increase new product commercial performance introduced by subsidiary in the local market.

  20. Fuzzy logic controller for weaning neonates from mechanical ventilation.

    OpenAIRE

    Hatzakis, G. E.; Davis, G. M.

    2002-01-01

    Weaning from mechanical ventilation is the gradual detachment from any ventilatory support till normal spontaneous breathing can be fully resumed. To date, we have developed a fuzzy logic controller for weaning COPD adults using pressure support ventilation (PS). However, adults and newborns differ in the pathophysiology of lung disease. We therefore used our fuzzy logic-based weaning platform to develop modularized components for weaning newborns with lung disease. Our controller uses the he...

  1. Control rod drive mechanism with shock absorber for nuclear reactor

    International Nuclear Information System (INIS)

    Chevereau, G.

    1989-01-01

    The mechanism usable in a PWR has a shaft carrying the bar vertically displaceable in the reactor internals and a dash pot with a hydraulic cylinder and a piston. The cylinder has a large diameter perforated upper section to the cylinder, a small diameter lower section, a piston traversed by the control rod sized to fit into the upper section and forced downwards when the control descends. The shock absorbing chamber is defined between the piston and the upper section [fr

  2. Control of a perturbed under-actuated mechanical system

    KAUST Repository

    Zayane, Chadia

    2015-11-05

    In this work, the trajectory tracking problem for an under-actuated mechanical system in presence of unknown input disturbances is addressed. The studied inertia wheel inverted pendulum falls in the class of non minimum phase systems. The proposed high order sliding mode control architecture including a controller and differentiator allows to track accurately the predefined trajectory and to stabilize the internal dynamics. The robustness of the proposed approach is illustrated through different perturbation and output noise configurations.

  3. Quality control of injection moulded micro mechanical parts

    DEFF Research Database (Denmark)

    Gasparin, Stefania; Tosello, Guido; Hansen, Hans Nørgaard

    2009-01-01

    Quality control of micro components is an increasing challenge. Smaller mechanical parts are characterized by smaller tolerance to be verified. This paper focuses on the dimensional verification of micro injection moulded components selected from an industrial application. These parts are measured...... using an Optical Coordinate Measuring Machine (OCMM), which guarantees fast surface scans suitable for in line quality control. The uncertainty assessment of the measurements is calculated following the substitution method. To investigate the influence parameters in optical coordinate metrology two...

  4. Eye mechanics and their implications for eye movement control

    NARCIS (Netherlands)

    Koene, Ansgar Roald

    2002-01-01

    The topic of this thesis is the investigation of the mechanical properties of the oculomotor system and the implications of these properties for eye movement control. The investigation was conducted by means of computer models and simulations. This allowed us to combine data from anatomy, physiology

  5. Fluid Mechanics of Wing Adaptation for Separation Control

    Science.gov (United States)

    Chandrasekhara, M. S.; Wilder, M. C.; Carr, L. W.; Davis, Sanford S. (Technical Monitor)

    1997-01-01

    The unsteady fluid mechanics associated with use of a dynamically deforming leading edge airfoil for achieving compressible flow separation control has been experimentally studied. Changing the leading edge curvature at rapid rates dramatically alters the flow vorticity dynamics which is responsible for the many effects observed in the flow.

  6. Mechanical verification of concurrency control and recovery protocols

    NARCIS (Netherlands)

    Chkliaev, D.

    2001-01-01

    The thesis concerns the formal specification and mechanized verification of concurrency control and recovery protocols for distributed databases. Such protocols are needed for many modern application such as banking and are often used in safety-critical applications. Therefore it is very important

  7. Quasivelocities and Optimal Control for underactuated Mechanical Systems

    International Nuclear Information System (INIS)

    Colombo, L.; Martin de Diego, D.

    2010-01-01

    This paper is concerned with the application of the theory of quasivelocities for optimal control for underactuated mechanical systems. Using this theory, we convert the original problem in a variational second-order lagrangian system subjected to constraints. The equations of motion are geometrically derived using an adaptation of the classical Skinner and Rusk formalism.

  8. Composite Control of the n–link Chained Mechanical Systems

    Czech Academy of Sciences Publication Activity Database

    Zikmund, Jiří

    2008-01-01

    Roč. 44, č. 5 (2008), s. 664-684 ISSN 0023-5954 R&D Projects: GA ČR(CZ) GA102/08/0186 Institutional research plan: CEZ:AV0Z10750506 Keywords : nonlinear systems * exact linearization * underactuated mechanical systems Subject RIV: BC - Control Systems Theory Impact factor: 0.281, year: 2008

  9. Sedimentary facies control on mechanical and fracture stratigraphy in turbidites

    NARCIS (Netherlands)

    Ogata, Kei; Storti, Fabrizio; Balsamo, Fabrizio; Tinterri, Roberto; Bedogni, Enrico; Fetter, Marcos; Gomes, Leonardo; Hatushika, Raphael

    2017-01-01

    Natural fracture networks exert a first-order control on the exploitation of resources such as aquifers, hydrocarbons, and geothermal reservoirs, and on environmental issues like underground gas storage and waste disposal. Fractures and the mechanical stratigraphy of layered sequences have been

  10. Electromagnetic design calculation of the control rod drive mechanism

    International Nuclear Information System (INIS)

    Zhu Qirong; Zhu Jingchang

    1991-01-01

    Electromagnetic design calculation of the step-by-step magnetic jacking control rod drive mechanism includes magnetic field force calculation and design calculation of magnetomotive force for three electromagnetic iron and their coilds. The basic principle and method of electromagnetic design calculation had been expounded to take the lift magnet and lift coil for example

  11. Biomechanics and energetics of walking in powered ankle exoskeletons using myoelectric control versus mechanically intrinsic control.

    Science.gov (United States)

    Koller, Jeffrey R; Remy, C David; Ferris, Daniel P

    2018-05-25

    Controllers for assistive robotic devices can be divided into two main categories: controllers using neural signals and controllers using mechanically intrinsic signals. Both approaches are prevalent in research devices, but a direct comparison between the two could provide insight into their relative advantages and disadvantages. We studied subjects walking with robotic ankle exoskeletons using two different control modes: dynamic gain proportional myoelectric control based on soleus muscle activity (neural signal), and timing-based mechanically intrinsic control based on gait events (mechanically intrinsic signal). We hypothesized that subjects would have different measures of metabolic work rate between the two controllers as we predicted subjects would use each controller in a unique manner due to one being dependent on muscle recruitment and the other not. The two controllers had the same average actuation signal as we used the control signals from walking with the myoelectric controller to shape the mechanically intrinsic control signal. The difference being the myoelectric controller allowed step-to-step variation in the actuation signals controlled by the user's soleus muscle recruitment while the timing-based controller had the same actuation signal with each step regardless of muscle recruitment. We observed no statistically significant difference in metabolic work rate between the two controllers. Subjects walked with 11% less soleus activity during mid and late stance and significantly less peak soleus recruitment when using the timing-based controller than when using the myoelectric controller. While walking with the myoelectric controller, subjects walked with significantly higher average positive and negative total ankle power compared to walking with the timing-based controller. We interpret the reduced ankle power and muscle activity with the timing-based controller relative to the myoelectric controller to result from greater slacking effects

  12. Seismic analysis of control and safety rod drive mechanism

    International Nuclear Information System (INIS)

    Meher Prasad, A.; Jaya, K.P.; Chellapandi, P.; Rajan Babu, V.; Selvaraj, T.

    2003-01-01

    Control rod and its driving mechanism for a Fast Breeder Reactor is to facilitate safe shutdown of the reactor in case of emergency. A theoretical study on the seismic qualification of control and safety rod driving mechanism is carried out. Earthquake excitations under Operational Basis (ORE) and Safe Shutdown condition (SSE) are considered. The time required for the control rod to reach the bottom position in order to shut down the reaction under excited condition is traced out. The maximum displaced positions and extreme stresses in various parts of the system under excitations are evaluated. The system modeled using beam elements. The connections between different parts are modeled through rigid elements. The interaction between various parts are modeled using GAP elements. (author)

  13. Control of Maillard Reactions in Foods: Strategies and Chemical Mechanisms.

    Science.gov (United States)

    Lund, Marianne N; Ray, Colin A

    2017-06-14

    Maillard reactions lead to changes in food color, organoleptic properties, protein functionality, and protein digestibility. Numerous different strategies for controlling Maillard reactions in foods have been attempted during the past decades. In this paper, recent advances in strategies for controlling the Maillard reaction and subsequent downstream reaction products in food systems are critically reviewed. The underlying mechanisms at play are presented, strengths and weaknesses of each strategy are discussed, and reasonable reaction mechanisms are proposed to reinforce the evaluations. The review includes strategies involving addition of functional ingredients, such as plant polyphenols and vitamins, as well as enzymes. The resulting trapping or modification of Maillard targets, reactive intermediates, and advanced glycation endproducts (AGEs) are presented with their potential unwanted side effects. Finally, recent advances in processing for control of Maillard reactions are discussed.

  14. Photophysical properties of novel Porphyrin-Flavin Dyads

    International Nuclear Information System (INIS)

    Stark, S.

    2001-10-01

    Photosynthesis belongs to the fundamentals of life on earth, therefore it is an important matter in natural sciences. The basic principle of photosynthesis is the transformation of solar light into chemical energy. The starting steps of photosynthesis are light-induced energy- and electron-transfer-steps with singular efficiency. One attempt to enlighten the molecular processes involved is to synthesize simpler model systems with similar properties. Important research goals are the dependencies of light-induced processes on distance and orientation of donor and acceptor. A second aim next to the clarification of the molecular conditions of photosynthesis is to create molecular light-driven machines. The most simple so-called biomimetic model system consists of an electron-donor connected to an electron-acceptor via a spacer-group. This simplest form is also referred to as dyad. Beyond dyads far more complicated compounds have been introduced consisting of several donors and/or acceptors, so-called triads, tetrads, pentads etc. Usually porphyrin serves as electron-donor. Next to chinones several other electron-acceptors are used, e.g. anthracene, pyromellitimide and fullerene. Artificial photosynthetic centers are often more stable and/or the excited states are easier to detect compared to the natural photosynthetic center. The photophysical characteristics of four dyads are reported in this work. The dyads consist of porphyrin (either free-base or zinc-metallated) and flavin, connected by different spacers. These dyads reveal photo-induced electron transfer from porphyrin to flavin and energy-transfer in the reversed direction with different efficiencies. The object of the study is the dependency of these processes on the structural features. The spacer of the dyads 1a-1c is an aromatic bridge which leads to well defined donor-acceptor distances. Because of this structure conjugation through the spacer is increased, whereas the absorption in the visible and near UV

  15. Sliding mode control on electro-mechanical systems

    Directory of Open Access Journals (Sweden)

    Vadim I. Utkin

    2002-01-01

    Full Text Available The first sliding mode control application may be found in the papers back in the 1930s in Russia. With its versatile yet simple design procedure the methodology is proven to be one of the most powerful solutions for many practical control designs. For the sake of demonstration this paper is oriented towards application aspects of sliding mode control methodology. First the design approach based on the regularization is generalized for mechanical systems. It is shown that stability of zero dynamics should be taken into account when the regular form consists of blocks of second-order equations. Majority of applications in the paper are related to control and estimation methods of automotive industry. New theoretical methods are developed in the context of these studies: sliding made nonlinear observers, observers with binary measurements, parameter estimation in systems with sliding mode control.

  16. Advance of Mechanically Controllable Break Junction for Molecular Electronics.

    Science.gov (United States)

    Wang, Lu; Wang, Ling; Zhang, Lei; Xiang, Dong

    2017-06-01

    Molecular electronics stands for the ultimate size of functional elements, keeping up with an unstoppable trend over the past few decades. As a vital component of molecular electronics, single molecular junctions have attracted significant attention from research groups all over the world. Due to its pronounced superiority, the mechanically controllable break junctions (MCBJ) technique has been widely applied to characterize the dynamic performance of single molecular junctions. This review presents a system analysis for single-molecule junctions and offers an overview of four test-beds for single-molecule junctions, thus offering more insight into the mechanisms of electron transport. We mainly focus on the development of state-of-the-art mechanically controlled break junctions. The three-terminal gated MCBJ approaches are introduced to manipulate the electron transport of molecules, and MCBJs are combined with characterization techniques. Additionally, applications of MCBJs and remarkable properties of single molecules are addressed. Finally, the challenges and perspective for the mechanically controllable break junctions technique are provided.

  17. Versatile cable handling mechanisms for remote operator control

    Energy Technology Data Exchange (ETDEWEB)

    Collie, A.A.; White, T.S.; Christopher, M.D.; Hewer, N.D. [Portech Ltd., Portsmouth (United Kingdom)

    1996-12-31

    This paper describes a system of cable management for keeping the umbilical cables of remote operating vehicles and manipulators tidy and contained without direct intervention by operators. Two distinct types of winding mechanism have been designed. One mechanism is a fixed reel type where the cable is wound onto the reel by a rotating bail arm. The other mechanism consists of a pair of curved belts held against each other between which cable is passed. The complete system includes tension measuring and slack loop take-up devices. The whole system is controlled by a servo system in conjunction with a PC based visual graphic environment which allows a variety of mechanisms to be built up into a system able to handle up to four umbilical cables simultaneously. The control system provides additional tension sensors and cable odometers connected to the control system so that the operator has immediate perception of all the cable parameters, and by defining rules, can set up a variety of alarm situations. (Author).

  18. Overview: Mechanism and Control of a Prosthetic Arm.

    Science.gov (United States)

    Kulkarni, Tushar; Uddanwadiker, Rashmi

    2015-09-01

    Continuous growth in industrialization and lack of awareness in safety parameters the cases of amputations are growing. The search of safer, simpler and automated prosthetic arms for managing upper limbs is expected. Continuous efforts have been made to design and develop prosthetic arms ranging from simple harness actuated to automated mechanisms with various control options. However due the cost constraints, the automated prosthetic arms are still out of the reach of needy people. Recent data have shown that there is a wide scope to develop a low cost and light weight upper limb prosthesis. This review summarizes the various designs methodologies, mechanisms and control system developed by the researchers and the advances therein. Educating the patient to develop acceptability to prosthesis and using the same for the most basic desired functions of human hand, post amputation care and to improve patient's independent life is equally important. In conclusion it can be interpreted that there is a wide scope in design in an adaptive mechanism for opening and closing of the fingers using other methods of path and position synthesis. Simple mechanisms and less parts may optimize the cost factor. Reduction in the weight of the prosthesis may be achieved using polymers used for engineering applications. Control system will remain never ending challenge for the researchers, but it is essential to maintain the simplicity from the patients perspective.

  19. Versatile cable handling mechanisms for remote operator control

    International Nuclear Information System (INIS)

    Collie, A.A.; White, T.S.; Christopher, M.D.; Hewer, N.D.

    1996-01-01

    This paper describes a system of cable management for keeping the umbilical cables of remote operating vehicles and manipulators tidy and contained without direct intervention by operators. Two distinct types of winding mechanism have been designed. One mechanism is a fixed reel type where the cable is wound onto the reel by a rotating bail arm. The other mechanism consists of a pair of curved belts held against each other between which cable is passed. The complete system includes tension measuring and slack loop take-up devices. The whole system is controlled by a servo system in conjunction with a PC based visual graphic environment which allows a variety of mechanisms to be built up into a system able to handle up to four umbilical cables simultaneously. The control system provides additional tension sensors and cable odometers connected to the control system so that the operator has immediate perception of all the cable parameters, and by defining rules, can set up a variety of alarm situations. (Author)

  20. Versatile cable handling mechanisms for remote operator control

    International Nuclear Information System (INIS)

    Collie, A.A.; White, T.S.; Christopher, M.D.; Hewer, N.D.

    1996-01-01

    This paper describes a system of cable management for keeping the umbilical cables of remote operating vehicles and manipulators tidy and contained without direct intervention by operators. Two distinct types of winding mechanism have been designed. One mechanism is a fixed reel type where the cable is wound onto the reel by a rotating bail arm. The other mechanism consists of a pair of curved belts held against each other, between which cable is passed. The complete system includes tension measuring and slack loop take-up devices. The whole system is controlled by a servo system in conjunction with a PC based visual graphic environment which allows a variety of mechanisms to be built up into a system able to handle up to four umbilical cables simultaneously. The control system provides additional tension sensors and cable odometers connected to the control system so that the operator has immediate perception of all the cable parameters, and by defining rules, can set up a variety of alarm situations. (UK)

  1. Hibernation Control Mechanism and Possible Applications to Humans

    Science.gov (United States)

    Kondo, N.

    Mammalian hibernation, characterized by the ability to survive temporarily at low body temperatures close to 0oC, has been reported to increase resistance to various lethal events such as low body temperature, severe ischemia, bacterial infection and irradiation, and to prolong the life span. The application of this physiological phenomenon to space life has been dreamed of. However, realization of this dream has been prevented by a poor understanding of the control mechanisms of hibernation. Recent findings of a novel and unique protein complex (HP) in the blood of chipmunks, a rodent hibernator, which is controlled by the endogenous circannual rhythm of hibernation, allowed new developments in understanding the molecular mechanism of hibernation and its physiological significance. From these studies, two hormones regulated by the brain were identified as promising candidate molecules controlling HP production in the liver, assuming that hibernation is controlled via the neuroendocrine system and regulated by the endogenous circannual rhythm in the brain. A circannual HP rhythm was observed in chipmunks maintaining euthermia under conditions of constant warmth, suggesting that the physiological control of hibernation progresses without a lowering of body temperature. Furthermore, the study of HP rhythm on longevity revealed that a circannual rhythm plays an essential role in the much longer life span of hibernators. The present progress in hibernation research may open a new pathway for manipulating a circannual rhythm controlling hibernation in humans. In the future, this will make it feasible to take advantage of hibernation in space life.

  2. Adaptive mechanism-based congestion control for networked systems

    Science.gov (United States)

    Liu, Zhi; Zhang, Yun; Chen, C. L. Philip

    2013-03-01

    In order to assure the communication quality in network systems with heavy traffic and limited bandwidth, a new ATRED (adaptive thresholds random early detection) congestion control algorithm is proposed for the congestion avoidance and resource management of network systems. Different to the traditional AQM (active queue management) algorithms, the control parameters of ATRED are not configured statically, but dynamically adjusted by the adaptive mechanism. By integrating with the adaptive strategy, ATRED alleviates the tuning difficulty of RED (random early detection) and shows a better control on the queue management, and achieve a more robust performance than RED under varying network conditions. Furthermore, a dynamic transmission control protocol-AQM control system using ATRED controller is introduced for the systematic analysis. It is proved that the stability of the network system can be guaranteed when the adaptive mechanism is finely designed. Simulation studies show the proposed ATRED algorithm achieves a good performance in varying network environments, which is superior to the RED and Gentle-RED algorithm, and providing more reliable service under varying network conditions.

  3. Photophysical properties of betaxanthins: Vulgaxanthin I in aqueous and alcoholic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Wendel, Monika [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland); Szot, Dominika; Starzak, Karolina; Tuwalska, Dorota [Faculty of Chemical Engineering and Technology, Institute C-1, Section of Analytical Chemistry, Cracow University of Technology, Warszawska 24, Cracow 31-155 (Poland); Gapinski, Jacek [Molecular Biophysics Department, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland); Naskrecki, Ryszard [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland); Prukala, Dorota; Sikorski, Marek [Faculty of Chemistry, Adam Mickiewicz University in Poznan, Umultowska 89b, Poznan 61-614 (Poland); Wybraniec, Slawomir [Faculty of Chemical Engineering and Technology, Institute C-1, Section of Analytical Chemistry, Cracow University of Technology, Warszawska 24, Cracow 31-155 (Poland); Burdzinski, Gotard, E-mail: gotardb@amu.edu.pl [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland)

    2015-11-15

    Betaxanthins are yellow pigments present in Caryophyllales plants and some higher fungi. We characterize photophysical properties of vulgaxanthin I and extracts of Amanita muscaria L. Vulgaxanthin I photoexcitation at λ{sub exc}=476 nm leads to the S{sub 1} excited state with the S{sub 1}→S{sub n} absorption bands at ca. 390 and 920 nm in both aqueous and alcoholic solutions. The S{sub 1} state lifetimes (2.9 and 37 ps in water) imply that vulgaxanthin I exists in two stereoisomeric forms. An increase in the solvent viscosity extends the S{sub 1} lifetimes and fluorescence quantum yields, probably due to hindered internal rotations in the dye. Internal conversion is the major S{sub 1} state deactivation path, with fluorescence being a minor channel, and S{sub 1}→T{sub 1} intersystem crossing not observed. Betaxanthins extracted from A. muscaria L. have similar properties. Efficient dissipation of the absorbed light energy as heat supports the postulate of photoprotective role of betaxanthins in vivo. - Highlights: • Betaxanthin S{sub 1} state deactivation mechanism is mainly radiationless. • S{sub 1} state shows absorption band with maxima at about 390 nm and 920 nm. • Solvent viscosity affects S{sub 1} state lifetime and fluorescence quantum yield. • Addition of potassium iodide to solution enhances ISC in betaxanthin.

  4. Controlled invasive mechanical ventilation strategies in obese patients undergoing surgery.

    Science.gov (United States)

    Maia, Lígia de Albuquerque; Silva, Pedro Leme; Pelosi, Paolo; Rocco, Patricia Rieken Macedo

    2017-06-01

    The obesity prevalence is increasing in surgical population. As the number of obese surgical patients increases, so does the demand for mechanical ventilation. Nevertheless, ventilatory strategies in this population are challenging, since obesity results in pathophysiological changes in respiratory function. Areas covered: We reviewed the impact of obesity on respiratory system and the effects of controlled invasive mechanical ventilation strategies in obese patients undergoing surgery. To date, there is no consensus regarding the optimal invasive mechanical ventilation strategy for obese surgical patients, and no evidence that possible intraoperative beneficial effects on oxygenation and mechanics translate into better postoperative pulmonary function or improved outcomes. Expert commentary: Before determining the ideal intraoperative ventilation strategy, it is important to analyze the pathophysiology and comorbidities of each obese patient. Protective ventilation with low tidal volume, driving pressure, energy, and mechanical power should be employed during surgery; however, further studies are required to clarify the most effective ventilation strategies, such as the optimal positive end-expiratory pressure and whether recruitment maneuvers minimize lung injury. In this context, an ongoing trial of intraoperative ventilation in obese patients (PROBESE) should help determine the mechanical ventilation strategy that best improves clinical outcome in patients with body mass index≥35kg/m 2 .

  5. Cable control and take-up mechanisms and x-ray scanning apparatus incorporating such mechanisms

    International Nuclear Information System (INIS)

    Braden, A.B.; Lekan, J.J.; Taylor, S.K.; Richey, J.B.

    1977-01-01

    In this patent, an invention for cable control and take-up mechanisms for elongated, flexible cables is described. Such cables are used in X-ray scanner apparatus to provide power, electronic signals and fluids. A detailed design and description is given of the cable harness, control and take-up mechanism that would be used in conjunction with an X-ray scanner. As a result of this invention, the cables are prevented from becoming prematurely worn or entangled in the X-ray apparatus during the rotational and translational movements necessary in tomographic examinations. This invention is also applicable to other types of apparatus and environments where a number of different positions is required and where it is necessary to control the take-up of elongated, flexible, cable-like members. (U.K.)

  6. New mechanism for the control of sodium transport in wheat

    International Nuclear Information System (INIS)

    James, R.A.; Munns, R.; Huang, C.X.

    2002-01-01

    Full text: Durum and other tetraploid wheats are typically very salt-sensitive compared to hexaploid bread wheats. This is primarily due to high rates of Na + accumulation in the leaves in tetraploid wheat. Recently, we have discovered a durum landrace with low Na + accumulation and enhanced K + /Na + discrimination, much lower than current durum cultivars and similar to bread wheat. We have identified 3 different mechanisms for the control of Na + transport to the leaves in this landrace, 1) control of Na + uptake at the epidermis of the root, 2) control of Na + loading into the xylem and 3) partitioning of Na + into the leaf sheath. The low Na + durum landrace had 3-4 fold lower Na + uptake rates than durum cultivars. Using X ray microanalysis on snap-frozen root sections, we found Na + to be high in the epidermis, a decreasing gradient through the cortex, low in the endodermis and again high in the stele (pencycle and xylem parenchyma), indicative of control points at the epidermis and in the stele. Partitioning of Na + between shoot and root was at least 5 times lower in the durum landrace, suggestive of greater control of Na + transport at the site of xylem loading. A third and novel control mechanism was found in the leaf sheath. Short and long term salinity treatments showed that Na + was partitioned preferentially into the sheaths of the low Na + durum landrace, keeping leaf blade Na + levels very low and similar to that of bread wheat Na + partitioned in the leaf sheath was stored primarily in the parenchyma cells and Cl - in the epidermal cells. Collectively, these data show that we have identified germplasm that has the potential to increase the salt tolerance of durum wheat. Additionally, as bread wheat does not contain the mechanism for partitioning Na + into the sheath, this trait may be useful for further increasing the salt tolerance of this species

  7. Comparative Study on New AQM Mechanisms for Congestion Control

    Directory of Open Access Journals (Sweden)

    Ramakrishna B B

    2013-09-01

    Full Text Available As usage of network goes increasing day by day, managing network traffic becomes a very difficult task. It is important to avoid high packet loss rates in the Internet. Congestion is the one of the major issue in the present networks. Congestion Control is one of the solutions adopted to solve the congestion issue and to control it. Numbers of queue management algorithms are proposed for congestion control and to reduce high packet loss rates. Active Queue Management (AQM is one such mechanism which provides better control over congestion. In this paper a study is made on recent load based AQM techniques that are proposed and its merits and shortfall is presented.

  8. Mechanical stress-controlled tunable active frequency-selective surface

    Science.gov (United States)

    Huang, Bo-Cin; Hong, Jian-Wei; Lo, Cheng-Yao

    2017-01-01

    This study proposes a tunable active frequency-selective surface (AFSS) realized by mechanically expanding or contracting a split-ring resonator (SRR) array. The proposed AFSS transfers mechanical stress from its elastic substrate to the top of the SRR, thereby achieving electromagnetic (EM) modulation without the need for an additional external power supply, meeting the requirements for the target application: the invisibility cloak. The operating mechanism of the proposed AFSS differs from those of other AFSSs, supporting modulations in arbitrary frequencies in the target range. The proposed stress-controlled or strain-induced EM modulation proves the existence of an identical and linear relationship between the strain gradient and the frequency shift, implying its suitability for other EM modulation ranges and applications.

  9. Photophysical properties of fullerenes prepared in an atmosphere of pyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Glenis, S.; Cooke, S.; Chen, X.; Labes, M.M. (Temple Univ., Philadelphia, PA (United States))

    1994-10-01

    Samples of C[sub 60] and C[sub 70] containing a variety of nitrogen-doped species were prepared by arc vaporization of graphite in the presence of pyrrole. Cage-doped fractions were isolated by column chromatography and characterized by mass spectroscopy, optical absorption, and fluorescence measurements. Mass spectra were consistent with the substitution of an even number of carbon atoms of the C[sub 60] and C[sub 70] cages by nitrogen atoms. Carbonaceous clusters including fragmented fullerenes containing hydrogen atoms were also formed. UV-visible spectral analysis indicated that there is an influence of the molecular weight on the fundamental [pi]-[pi]* electronic transition. Fluorescence spectra showed a broad band containing vibrational fine structure that is attributed to photoseparated charges in the fragmented fullerenes and a shoulder on the low-energy side that is related to intrinsic excitation in the nitrogen-doped species. Fluorescence results imply a bandgap of 2.36 eV for the N doped fullerenes and the existence of intermediate excitonic transitions below the optical bandgap. Although it has not yet been possible to isolate a pure cage-doped material, the photophysical studies add credence to their existence and the importance of further attempts at their isolation. 17 refs., 4 figs., 1 tab.

  10. Mirror boxes and mirror mounts for photophysics beamline

    International Nuclear Information System (INIS)

    Raja Rao, P.M.; Raja Sekhar, B.N.; Das, N.C.; Khan, H.A.; Bhattacharya, S.S.; Roy, A.P.

    1996-01-01

    Photophysics beamline makes use of one metre Seya-Namioka monochromator and two toroidal mirrors in its fore optics. The first toroidal mirror (pre mirror) focuses light originating from the tangent point of the storage ring onto the entrance slit of the monochromator and second toroidal mirror (post mirror) collects light from the exit slit of the monochromator and focuses light onto the sample placed at a distance of about one metre away from the 2nd mirror. To steer light through monochromator and to focus it on the sample of 1mm x 1mm size require precision rotational and translational motion of the mirrors and this has been achieved with the help of precision mirror mounts. Since Indus-1 operates at pressures less than 10 -9 m.bar, the mirror mounts should be manipulated under similar ultra high vacuum conditions. Considering these requirements, two mirror boxes and two mirror mounts have been designed and fabricated. The coarse movements to the mirrors are imparted from outside the mirror chamber with the help of x-y tables and precision movements to the mirrors are achieved with the help of mirror mounts. The UHV compatibility and performance of the mirror mounts connected to mirror boxes under ultra high vacuum condition is evaluated. The details of the design, fabrication and performance evaluation are discussed in this report. 5 refs., 9 figs., 1 tab

  11. Photophysical investigation of cyano-substituted terrylenediimide derivatives.

    Science.gov (United States)

    Kennes, Koen; Baeten, Yannick; Vosch, Tom; Sempels, Wouter; Yordanov, Stoyan; Stappert, Sebastian; Chen, Long; Müllen, Klaus; Hofkens, Johan; Van der Auweraer, Mark; Fron, Eduard

    2014-12-18

    Two new terrylenediimide (TDI) chromophores with cyano substituents in the bay and core area (BCN-TDI and OCN-TDI, respectively) have been characterized by a wide range of techniques, and their applicability for stimulated emission depletion (STED) microscopy has been tested. By cyano substitution an increase of the fluorescence quantum yield and a decrease of the nonradiative rate constant is achieved and attributed to a reduced charge-transfer character of the excited state due to a lower electron density of the TDI core. For BCN-TDI, the substitution in the bay area induces a strong torsional twist in the molecule which, similar to phenoxy bay-perylenediimide (PDI), has a strong effect on the fluorescence lifetime but appears to prevent the aggregation that is observed for OCN-TDI. The single-molecule photobleaching stability of BCN- and OCN-TDI is lower than that of a reference TDI without cyano substitution (C7-TDI), although less so for OCN-TDI. The photophysical properties of the excited singlet state are only slightly influenced by the cyano groups. The observed intense stimulated emission, the pump-dump-probe experiments, and STED single-molecule imaging indicate that STED experiments with the cyano-substituted TDIs are possible. However, because of aggregation and more efficient photobleaching, the performance of BCN- and OCN-TDI is worse than that of the reference compound without cyano groups (C7-TDI). Bay-substituted TDIs are less suitable for STED microscopy.

  12. The Photo-Physics of Polythiophene Nanoparticles for Biological Applications.

    Science.gov (United States)

    Bargigia, Ilaria; Zucchetti, Elena; Srimath Kandada, Ajay Ram; Moreira, Miguel; Bossio, Caterina; Wong, Walter; Miranda, Paulo; Decuzzi, Paolo; Soci, Cesare; D'Andrea, Cosimo; Lanzani, Guglielmo

    2018-05-01

    In this work the photo-physics of poly(3-hexyltiophene) nanoparticles (NPs) is investigated in the context of their biological applications. The NPs made as colloidal suspensions in aqueous buffers present a distinct absorption band in the low energy region. Based on systematic analysis of absorption and transient absorption spectra taken under different pH conditions, this band is associated to charge transfer states generated by the polarization of loosely bound polymer chains and originated from complexes formed with electron withdrawing species. Importantly, the ground state depletion of these states upon photo-excitation is active even in the microsecond timescales, suggesting that they act as precursor states for long-living polarons which could be beneficial for cellular stimulation. Preliminary results of transient absorption microscopy of NPs internalized within the cells reveal the presence of long-living species, further substantiating their relevance in bio-interfaces. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Mechanization and Control Concepts for Biologically Inspired Micro Aerial Vehicles

    Science.gov (United States)

    Raney, David L.; Slominski, Eric C.

    2003-01-01

    It is possible that MAV designs of the future will exploit flapping flight in order to perform missions that require extreme agility, such as rapid flight beneath a forest canopy or within the confines of a building. Many of nature's most agile flyers generate flapping motions through resonant excitation of an aeroelastically tailored structure: muscle tissue is used to excite a vibratory mode of their flexible wing structure that creates propulsion and lift. A number of MAV concepts have been proposed that would operate in a similar fashion. This paper describes an ongoing research activity in which mechanization and control concepts with application to resonant flapping MAVs are being explored. Structural approaches, mechanical design, sensing and wingbeat control concepts inspired by hummingbirds, bats and insects are examined. Experimental results from a testbed capable of generating vibratory wingbeat patterns that approximately match those exhibited by hummingbirds in hover, cruise, and reverse flight are presented.

  14. Electromagnetic analysis of control element drive mechanism for KSNP

    International Nuclear Information System (INIS)

    Kim, H. M.; Kim, I. G.; Kim, I. Y.

    2002-01-01

    The magnetic jack type Control Element Drive Mechanism (CEDM) for Korean Standard Nuclear Power Plant (KSNP) is an electromechanical device which provides controlled linear motion to the Control Element Assembly (CEA) through the Extension Shaft Assembly (ESA) in response to operational signals received from the Control Element Drive Mechanism Control System (CEDMCS). The CEDM is operated by applying localized magnetic flux fields to movable latch and lift magnets, which are in the coolant pressure boundary. The CEDM design had been developed through electromechanical testing of the system including the magnetic force lifting the ESA. But it will be inefficient if parametric studies should be performed to improve the CEDM by test due to the consumption of high cost and long duration. So it becomes necessary to develop a computational model to simulate the electromagnetic characteristics of the CEDM to improve the CEDM design efficiently. In this paper, the electromagnetic analysis using a 2D finite element model has been carried out to simulate magnetic force of the lift magnet of the CEDM, to provide effective evaluation between leakage flux and lift force and to compare with test results. Analysis results show the lift force satisfied the test results and design requirement and the lift force depend on the shape of the components, leakage flux and B-H curve

  15. Mechanical control of mitotic progression in single animal cells

    OpenAIRE

    Cattin, Cedric J.; Düggelin, Marcel; Martinez-Martin, David; Gerber, Christoph; Müller, Daniel J.; Stewart, Martin P.

    2015-01-01

    Despite the importance of mitotic cell rounding in tissue development and cell proliferation, there remains a paucity of approaches to investigate the mechanical robustness of cell rounding. Here we introduce ion beam-sculpted microcantilevers that enable precise force-feedback-controlled confinement of single cells while characterizing their progression through mitosis. We identify three force regimes according to the cell response: small forces (∼5 nN) that accelerate mitotic progression, i...

  16. Multi-finger prehension: control of a redundant mechanical system.

    Science.gov (United States)

    Latash, Mark L; Zatsiorsky, Vladimir M

    2009-01-01

    The human hand has been a fascinating object of study for researchers in both biomechanics and motor control. Studies of human prehension have contributed significantly to the progress in addressing the famous problem of motor redundancy. After a brief review of the hand mechanics, we present results of recent studies that support a general view that the apparently redundant design of the hand is not a source of computational problems but a rich apparatus that allows performing a variety of tasks in a reliable and flexible way (the principle of abundance). Multi-digit synergies have been analyzed at two levels of a hypothetical hierarchy involved in the control of prehensile actions. At the upper level, forces and moments produced by the thumb and virtual finger (an imagined finger with a mechanical action equal to the combined mechanical action of all four fingers of the hand) co-vary to stabilize the gripping action and the orientation of the hand-held object. These results support the principle of superposition suggested earlier in robotics with respect to the control of artificial grippers. At the lower level of the hierarchy, forces and moments produced by individual fingers co-vary to stabilize the magnitude and direction of the force vector and the moment of force produced by the virtual finger. Adjustments to changes in task constraints (such as, for example, friction under individual digits) may be local and synergic. The latter reflect multi-digit prehension synergies and may be analyzed with the so-called chain effects: Sequences of relatively straightforward cause-effect links directly related to mechanical constraints leading to non-trivial strong co-variation between pairs of elemental variables. Analysis of grip force adjustments during motion of hand-held objects suggests that the central nervous system adjusts to gravitational and inertial loads differently. The human hand is a gold mine for researchers interested in the control of natural human

  17. Thermal Mechanisms for High Amplitude Aerodynamic Flow Control (YIP 2012)

    Science.gov (United States)

    2016-04-15

    transport aircraft , much less cruise. The search for a perfect actuator continues, but progress has been limited by the often proprietary nature these...wave generation as a mechanism for high amplitude, high bandwidth actuation has been demonstrated, but the fundamental physics of how this...moving forward with such a definition. 15. SUBJECT TERMS active flow control, energy deposition, plasma actuation 16. SECURITY CLASSIFICATION OF: 17

  18. Conceptual Design of Bottom-mounted Control Rod Drive Mechanism

    International Nuclear Information System (INIS)

    Lee, Jin Haeng; Kim, Sanghaun; Yoo, Yeonsik; Cho, Yeonggarp; Kim, Dongmin; Kim, Jong In

    2013-01-01

    The arrangement of the BMCRDMs and irradiation holes in the core is therefore easier than that of the top-mounted CRDM. Hence, many foreign research reactors, such as JRR-3M, JMTR, OPAL, and CARR, have adopted the BMCRDM concept. The purpose of this paper is to introduce the basic design concept on the BMCRDM. The major differences of the CRDMs between HANARO and KJRR are compared, and the design features and individual system of the BMCRDM for the KJRR are described. The Control Rod Drive Mechanism (CRDM) is a device to regulate the reactor power by changing the position of a Control Absorber Rod (CAR) and to shut down the reactor by fully inserting the CAR into the core within a specified time. The Bottom-Mounted CRDM (BMCRDM) for the KiJang Research Reactor (KJRR) is a quite different design concept compared to the top-mounted CRDM such as HANARO and JRTR. The main drive mechanism of the BMCRDM is located in a Reactivity Control Mechanism (RCM) room under the reactor pool bottom, which makes the interference with equipment in the reactor pool reduced

  19. Conceptual Design of Bottom-mounted Control Rod Drive Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Haeng; Kim, Sanghaun; Yoo, Yeonsik; Cho, Yeonggarp; Kim, Dongmin; Kim, Jong In [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    The arrangement of the BMCRDMs and irradiation holes in the core is therefore easier than that of the top-mounted CRDM. Hence, many foreign research reactors, such as JRR-3M, JMTR, OPAL, and CARR, have adopted the BMCRDM concept. The purpose of this paper is to introduce the basic design concept on the BMCRDM. The major differences of the CRDMs between HANARO and KJRR are compared, and the design features and individual system of the BMCRDM for the KJRR are described. The Control Rod Drive Mechanism (CRDM) is a device to regulate the reactor power by changing the position of a Control Absorber Rod (CAR) and to shut down the reactor by fully inserting the CAR into the core within a specified time. The Bottom-Mounted CRDM (BMCRDM) for the KiJang Research Reactor (KJRR) is a quite different design concept compared to the top-mounted CRDM such as HANARO and JRTR. The main drive mechanism of the BMCRDM is located in a Reactivity Control Mechanism (RCM) room under the reactor pool bottom, which makes the interference with equipment in the reactor pool reduced.

  20. Mechanical design and optimal control of humanoid robot (TPinokio

    Directory of Open Access Journals (Sweden)

    Teck Chew Wee

    2014-04-01

    Full Text Available The mechanical structure and the control of the locomotion of bipedal humanoid is an important and challenging domain of research in bipedal robots. Accurate models of the kinematics and dynamics of the robot are essential to achieve bipedal locomotion. Toe-foot walking produces a more natural and faster walking speed and it is even possible to perform stretch knee walking. This study presents the mechanical design of a toe-feet bipedal, TPinokio and the implementation of some optimal walking gait generation methods. The optimality in the gait trajectory is achieved by applying augmented model predictive control method and the pole-zero cancellation method, taken into consideration of a trade-off between walking speed and stability. The mechanism of the TPinokio robot is designed in modular form, so that its kinematics can be modelled accurately into a multiple point-mass system, its dynamics is modelled using the single and double mass inverted pendulum model and zero-moment-point concept. The effectiveness of the design and control technique is validated by simulation testing with the robot walking on flat surface and climbing stairs.

  1. Photophysical properties, photodegradation characteristics, and lasing action for coumarin dye C540A in polymeric media

    Science.gov (United States)

    Jones, Guilford, II; Huang, Zhennian; Pacheco, Dennis P., Jr.; Russell, Jeffrey A.

    2004-07-01

    Tunable solid-state dye lasers operating in the blue-green spectral region are attractive for a variety of applications. An important consideration in assessing the viability of this technology is the service life of the gain medium, which is presently limited by dye photodegradation. In this study, solid polymeric samples consisting of the coumarin dye C540A in modified PMMA were subjected to controlled photodegradation tests. The excitation laser was a flashlamp-pumped dye laser operating at 440 nm with a pulse duration of 1 μs. A complementary set of data was obtained for dye in solution phase for comparison purposes. Photophysical properties of C540A in water solution of polymethacrylic acid (PMAA) have been investigated with a view to assess the suitability of the sequestering polymer (PMAA) as an effective additive to facilitate use of a water medium for highly efficient blue-green dye lasers. Lasing action of C540A in aqueous PMAA has been realized using flashlamp-pumped laser system, yielding excellent laser efficiencies superior to that achieved in ethanolic solutions with the same dye. Laser characterization of dye in media included measurement of laser threshold, slope efficiency, pulse duration and output wavelength.

  2. Photophysical Properties of II-VI Semiconductor Nanocrystals

    Science.gov (United States)

    Gong, Ke

    terms of a Boltzmann population of exciton sublevels and calculated electron and hole wave functions. Much of the absorption data and fine structure calculations are already in the literature. These results are combined with new measurements of radiative lifetimes and electron-hole overlap calculations to produce an integrated picture of the II-VI QD spectroscopic fundamentals. Finally, we adopt recent synthetic advances to make very monodisperse zincblende CdSe/CdS quantum dots having near-unity photoluminescence quantum yields (PLQYs). Due the absence of nonradiative decay pathways, accurate values of the radiative lifetimes can be obtained from time resolved PL measurements. Radiative lifetimes can also be obtained from the Einstein relations, using the static absorption spectra and the relative thermal populations in the angular momentum sublevels. One of the inputs into these calculations is the shell thickness, and it is useful to be able to determine shell thickness from spectroscopic measurements. We use an empirically corrected effective mass model to produce a "map" of exciton wavelength as a function of core size and shell thickness. These calculations use an elastic continuum model and the known lattice and elastic constants to include the effect of lattice strain on the band gap energy. Radiative lifetimes calculated both experimentally and theoretically are checked and the size dependence is compared to previous studied Type-I, II and single component particles. However, it is not enough to just understanding these basic photophysics of absorption and emission. The emission intensities (related to QYs) also change with changes of the temperature. The temperature dependent PLs of II-VI QDs is extensively studied, but most of this work is at low temperatures. Temperatures well above ambient are of interest to lighting applications and in this regime both the reversible and irreversible loss of quantum yield (thermal quenching) are serious impediments to the

  3. Dynamics and control of mechanical systems in offshore engineering

    CERN Document Server

    He, Wei; How, Bernard Voon Ee; Choo, Yoo Sang

    2014-01-01

    Dynamics and Control of Mechanical Systems in Offshore Engineering is a comprehensive treatment of marine mechanical systems (MMS) involved in processes of great importance such as oil drilling and mineral recovery. Ranging from nonlinear dynamic modeling and stability analysis of flexible riser systems, through advanced control design for an installation system with a single rigid payload attached by thrusters, to robust adaptive control for mooring systems, it is an authoritative reference on the dynamics and control of MMS. Readers will gain not only a complete picture of MMS at the system level, but also a better understanding of the technical considerations involved and solutions to problems that commonly arise from dealing with them. The text provides:                                                                                                                                 ...

  4. Bilingualism modulates dual mechanisms of cognitive control: Evidence from ERPs.

    Science.gov (United States)

    Morales, Julia; Yudes, Carolina; Gómez-Ariza, Carlos J; Bajo, M Teresa

    2015-01-01

    Recent behavioral findings with the AX-Continous Performance Task (AX-CPT; Morales et al., 2013) show that bilinguals only outperform monolinguals under conditions that require the highest adjustment between monitoring (proactive) and inhibitory (reactive) control, which supports the idea that bilingualism modulates the coordination of different control mechanisms. In an ERP experiment we aimed to further investigate the role that bilingualism plays in the dynamic combination of proactive and reactive control in the AX-CPT. Our results strongly indicate that bilingualism facilitates an effective adjustment between both components of cognitive control. First, we replicated previous behavioral results. Second, ERP components indicated that bilingualism influences the conflict monitoring, response inhibition and error monitoring components of control (as indexed by the N2 and P3a elicited by the probe and the error-related negativity following incorrect responses, respectively). Thus, bilinguals exerted higher reactive control than monolinguals but only when they needed to overcome the competing cue-information. These findings join others in suggesting that a better understanding of the cognitive benefits of bilingualism may require consideration of a multi-component perspective. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Model Predictive Vibration Control Efficient Constrained MPC Vibration Control for Lightly Damped Mechanical Structures

    CERN Document Server

    Takács, Gergely

    2012-01-01

    Real-time model predictive controller (MPC) implementation in active vibration control (AVC) is often rendered difficult by fast sampling speeds and extensive actuator-deformation asymmetry. If the control of lightly damped mechanical structures is assumed, the region of attraction containing the set of allowable initial conditions requires a large prediction horizon, making the already computationally demanding on-line process even more complex. Model Predictive Vibration Control provides insight into the predictive control of lightly damped vibrating structures by exploring computationally efficient algorithms which are capable of low frequency vibration control with guaranteed stability and constraint feasibility. In addition to a theoretical primer on active vibration damping and model predictive control, Model Predictive Vibration Control provides a guide through the necessary steps in understanding the founding ideas of predictive control applied in AVC such as: ·         the implementation of ...

  6. Bottom-mounted control rod drive mechanism for KJRR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Haeng; Kim, Sanghaun; Yoo, Yeon-Sik, E-mail: yooys@kaeri.re.kr; Cho, Yeong-Garp; Huh, Hyung; Lee, Hyokwang; Sun, Jong-Oh; Ryu, Jeong-Soo

    2016-04-15

    Highlights: • The basic design features and characteristics of the KJRR BMCRDM are described. • The similarities and differences of some research reactor CRDMs are compared. • The current status of the design and development of the CRDM is described. • The future plan of the qualification tests of the CRDM is summarized. - Abstract: The KIJANG research reactor (KJRR), which is currently being designed by Korea Atomic Energy Research Institute, is a pool type research reactor with 15 MW of thermal power. Contrary to the top-mounted control rod drive mechanism (CRDM), the main drive mechanism of the KJRR CRDM is located in a reactivity control mechanism room under the reactor pool bottom. Recently, we accomplished the design and development of a prototype CRDM. In this paper, we introduce the basic design concept of the bottom-mounted CRDM for KJRR, and compare the similarities and differences of some research reactor CRDMs. The current status of the prototype CRDM development based on a finite element analysis and experimental verification, and the future plan of the CRDM qualification tests, are both described.

  7. Synthesis, photophysical and electrochemical properties of water–soluble phthalocyanines bearing 8-hydroxyquinoline-5-sulfonicacid derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Günsel, Armağan; Kocabaş, Sibel; Bilgiçli, Ahmet T. [Department of Chemistry, Sakarya University, 54140 Esentepe, Sakarya (Turkey); Güney, Sevgi [Department of Chemistry, Istanbul Technical University, 34469 Maslak, Istanbul (Turkey); Kandaz, Mehmet, E-mail: mkandaz@sakarya.edu.tr [Department of Chemistry, Sakarya University, 54140 Esentepe, Sakarya (Turkey)

    2016-08-15

    We have presented in this paper, the synthesis, characterization, photophysical properties and electrochemical characterization of water soluble phthalocyanines (Pcs) bearing 8-hydroxyquinoline-5-sulfonicacid conjugates and their cationic quaternized counterpart that play important roles their application in photodynamic therapy (PDT). The periphery and non-periphery substituted phthalocyanines show high solubility and low aggregation tendency due to bulky 8-hydroxyquinoline-5-sulfonicacid steric hindrance moieties and axially bound counter chlorine anion. Singlet oxygen quantum yields, photodegradation quantum yields, photophysical properties and also the nature of the substituent and solvent effect on the photophysical and photochemical parameters of α-ZnPc and β-ZnPc are reported. In electrovalent cobalt (II) and manganese (III) compounds, metal based electron transfer reactions have been observed in addition to the common phthalocyanine ring-based electron transfer processes. The effect of point of substitution on the electrochemical properties of newly synthesized phthalocyanines substituted with 8-hydroxyquinoline-5-sulfonicacid group were evaluated.

  8. Study on dynamic lifting characteristics of control rod drive mechanism

    International Nuclear Information System (INIS)

    Shen Xiaoyao

    2012-01-01

    Based on the equations of the electric circuit and the magnetic circuit and analysis of the dynamic lifting process for the control rod drive mechanism (CRDM), coupled magnetic-electric-mechanical equations both for the static status and the dynamic status are derived. The analytical method is utilized to obtain the current and the time when the lift starts. The numerical simulation method of dynamic analysis recommended by ASME Code is utilized to simulate the dynamic lifting process of CRDM, and the dynamic features of the system with different design gaps are studied. Conclusions are drawn as: (1) the lifting-start time increases with the design gap, and the time for the lifting process is longer with larger gaps; (2) the lifting velocity increases with time; (3) the lifting acceleration increases with time, and with smaller gaps, the impact acceleration is larger. (author)

  9. Theoretical investigation of the photophysics of methyl salicylate isomers

    Science.gov (United States)

    Massaro, Richard D.; Blaisten-Barojas, Estela

    2011-10-01

    The photophysics of methyl salicylate (MS) isomers has been studied using time-dependent density functional theory and large basis sets. First electronic singlet and triplet excited states energies, structure, and vibrational analysis were calculated for the ketoB, enol, and ketoA isomers. It is demonstrated that the photochemical pathway involving excited state intramolecular proton transfer (ESIPT) from the ketoB to the enol tautomer agrees well with the dual fluorescence in near-UV (from ketoB) and blue (from enol) wavelengths obtained from experiments. Our calculation confirms the existence of a double minimum in the excited state pathway along the O-H-O coordinate corresponding to two preferred energy regions: (1) the hydrogen belongs to the OH moiety and the structure of methyl salicylate is ketoB; (2) the hydrogen flips to the closest carboxyl entailing electronic rearrangement and tautomerization to the enol structure. This double well in the excited state is highly asymmetric. The Franck-Condon vibrational overlap is calculated and accounts for the broadening of the two bands. It is suggested that forward and backward ESIPT through the barrier separating the two minima is temperature-dependent and affects the intensity of the fluorescence as seen in experiments. When the enol fluoresces and returns to its ground state, a barrier-less back proton transfer repopulates the ground state of methyl salicylate ketoB. It is also demonstrated that the rotamer ketoA is not stable in an excited state close to the desired emission wavelength. This observation eliminates the conjecture that the near-UV emission of the dual fluorescence originates from the ketoA rotamer. New experimental results for pure MS in the liquid state are reported and theoretical results compared to them.

  10. Speed Controlled Belt Conveyors: Drives and Mechanical Considerations

    Directory of Open Access Journals (Sweden)

    BEBIC, M. Z.

    2018-02-01

    Full Text Available The paper presents variable speed belt conveyor system where the reference speed is changed in order to achieve improved energy efficiency of operation. The recorded measurements show that belt tension varies within the same limits as under constant speed operation. These results introduce a new insight of the present state of the art in variable speed belt conveyor drives. The system is realized with remote control from the control center on an open pit mine. The structure of the multi-motor drive system of a single conveyor, as well as of the network-based control system distributed among belt conveyor stations and the control center are shown. Speed control of a belt conveyor system is organized to provide better utilization of the available material cross section on the belt and reduced electrical energy consumption of the drive. The experimental results obtained on the system prove that, under existing constraints, the applied algorithm has not introduced additional stress to the belt or mechanical assemblies during acceleration and deceleration processes, while providing higher energy efficiency of operation.

  11. Chromophore photophysics and dynamics in fluorescent proteins of the GFP family

    International Nuclear Information System (INIS)

    Nienhaus, Karin; Nienhaus, G Ulrich

    2016-01-01

    Proteins of the green fluorescent protein (GFP) family are indispensable for fluorescence imaging experiments in the life sciences, particularly of living specimens. Their essential role as genetically encoded fluorescence markers has motivated many researchers over the last 20 years to further advance and optimize these proteins by using protein engineering. Amino acids can be exchanged by site-specific mutagenesis, starting with naturally occurring proteins as templates. Optical properties of the fluorescent chromophore are strongly tuned by the surrounding protein environment, and a targeted modification of chromophore-protein interactions requires a profound knowledge of the underlying photophysics and photochemistry, which has by now been well established from a large number of structural and spectroscopic experiments and molecular-mechanical and quantum-mechanical computations on many variants of fluorescent proteins. Nevertheless, such rational engineering often does not meet with success and thus is complemented by random mutagenesis and selection based on the optical properties. In this topical review, we present an overview of the key structural and spectroscopic properties of fluorescent proteins. We address protein-chromophore interactions that govern ground state optical properties as well as processes occurring in the electronically excited state. Special emphasis is placed on photoactivation of fluorescent proteins. These light-induced reactions result in large structural changes that drastically alter the fluorescence properties of the protein, which enables some of the most exciting applications, including single particle tracking, pulse chase imaging and super-resolution imaging. We also present a few examples of fluorescent protein application in live-cell imaging experiments. (topical review)

  12. Chromophore photophysics and dynamics in fluorescent proteins of the GFP family

    Science.gov (United States)

    Nienhaus, Karin; Nienhaus, G. Ulrich

    2016-11-01

    Proteins of the green fluorescent protein (GFP) family are indispensable for fluorescence imaging experiments in the life sciences, particularly of living specimens. Their essential role as genetically encoded fluorescence markers has motivated many researchers over the last 20 years to further advance and optimize these proteins by using protein engineering. Amino acids can be exchanged by site-specific mutagenesis, starting with naturally occurring proteins as templates. Optical properties of the fluorescent chromophore are strongly tuned by the surrounding protein environment, and a targeted modification of chromophore-protein interactions requires a profound knowledge of the underlying photophysics and photochemistry, which has by now been well established from a large number of structural and spectroscopic experiments and molecular-mechanical and quantum-mechanical computations on many variants of fluorescent proteins. Nevertheless, such rational engineering often does not meet with success and thus is complemented by random mutagenesis and selection based on the optical properties. In this topical review, we present an overview of the key structural and spectroscopic properties of fluorescent proteins. We address protein-chromophore interactions that govern ground state optical properties as well as processes occurring in the electronically excited state. Special emphasis is placed on photoactivation of fluorescent proteins. These light-induced reactions result in large structural changes that drastically alter the fluorescence properties of the protein, which enables some of the most exciting applications, including single particle tracking, pulse chase imaging and super-resolution imaging. We also present a few examples of fluorescent protein application in live-cell imaging experiments.

  13. Modelling and Simulation of Volume Controlled Mechanical Ventilation System

    Directory of Open Access Journals (Sweden)

    Yan Shi

    2014-01-01

    Full Text Available Volume controlled mechanical ventilation system is a typical time-delay system, which is applied to ventilate patients who cannot breathe adequately on their own. To illustrate the influences of key parameters of the ventilator on the dynamics of the ventilated respiratory system, this paper firstly derived a new mathematical model of the ventilation system; secondly, simulation and experimental results are compared to verify the mathematical model; lastly, the influences of key parameters of ventilator on the dynamics of the ventilated respiratory system are carried out. This study can be helpful in the VCV ventilation treatment and respiratory diagnostics.

  14. Stepping movement analysis of control rod drive mechanism

    International Nuclear Information System (INIS)

    Xu Yantao; Zu Hongbiao

    2013-01-01

    Background: Control rod drive mechanism (CRDM) is one of the important safety-related equipment for nuclear power plants. Purpose: The operating parameters of stepping movement, including lifting loads, step distance and step velocity, are all critical design targets. Methods: FEA and numerical simulation are used to analyze stepping movement separately. Results: The motion equations of the movable magnet in stepping movement are established by load analysis. Gravitation, magnetic force, fluid resistance and spring force are all in consideration in the load analysis. The operating parameters of stepping movement are given. Conclusions: The results, including time history curves of force, speed and etc, can positively used in the design of CRDM. (authors)

  15. Control rod drive mechanism stator loss of coolant test

    International Nuclear Information System (INIS)

    Besel, L.; Ibatuan, R.

    1977-04-01

    This report documents the stator loss of coolant test conducted at HEDL on the lead unit Control Rod Drive Mechanism (CRDM) in February, 1977. The purpose of the test was to demonstrate scram capability of the CRDM with an uncooled stator and to obtain a time versus temperature curve of an uncooled stator under power. Brief descriptions of the test, hardware used, and results obtained are presented in the report. The test demonstrated that the CRDM could be successfully scrammed with no anomalies in both the two-phase and three-phase stator winding hold conditions after the respective equilibrium stator temperatures had been obtained with no stator coolant

  16. Studies on the photophysical properties of 1,8-naphthalimide derivative and aggregation induced emission recognition for casein

    International Nuclear Information System (INIS)

    Sun, Yang; Liang, Xuhua; Fan, Jun; Han, Quan

    2013-01-01

    A novel water-soluble 1,8-naphthalimide derivative 1, bearing two acetic carboxylic groups, exhibited fluorescent turn-on recognition for casein micelle based on the aggregation induced emission (AIE) character. The photophysical properties of 1 consisting of donor and acceptor units were investigated by the solvation effect. Changing from polar to non-polar solvent increased the solvent interaction; both the excitation and emission spectra were shifted to shorter wavelength and intensity decreased through taking advantage of twisted intramolecular charge transfer (TICT) and self-association fluorescence emission. Moreover, the red-shift and quenching in protic solvent were caused by the excited-state hydrogen bond strengthening effect. The density functional theory (DFT) and time dependent density functional theory (TDDFT) were used to obtain the most stable structure, electronic excitation energy, dipole moments and charge distribution. The AIE mechanism of 1 with casein micelle was due to 1 docked in the hydrophobic cavity between sub-micelles and bound with amino acid residues, resulting in the aggregation of 1 on the casein micelle surface and emission enhancement, based on which, a novel casein assay method was developed. The proposed method exhibited a good linear range from 0.1 to 10.5 μg mL −1 , with the detection limit of 3.0 ng mL −1 . Satisfactory reproducibility, reversibility and a short response time were realized. This method was applied for the determination of casein in milk powder samples, avoiding the interferences from other components and illegal additives in milk. -- Highlights: • A water-soluble 1,8-naphthalimide-based fluorescent probe 1 was synthesized. • Photophysical characterization of 1 was studied. • Aggregation induced emission enhancement of 1 with casein was investigated. • A novel casein quantification method was developed

  17. Studies on the photophysical properties of 1,8-naphthalimide derivative and aggregation induced emission recognition for casein

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yang, E-mail: 66160692@qq.com [Department of Chemistry and Chemical Engineering, Xi' an University of Arts and Science, No. 168, Taibai South Road, Xi' an, Shaanxi 710065 (China); Liang, Xuhua; Fan, Jun [School of Chemical Engineering, Northwest University, No. 229, Taibai North Road, Xi' an, Shaanxi 710069 (China); Han, Quan, E-mail: xahanq@hotmail.com [Department of Chemistry and Chemical Engineering, Xi' an University of Arts and Science, No. 168, Taibai South Road, Xi' an, Shaanxi 710065 (China)

    2013-09-15

    A novel water-soluble 1,8-naphthalimide derivative 1, bearing two acetic carboxylic groups, exhibited fluorescent turn-on recognition for casein micelle based on the aggregation induced emission (AIE) character. The photophysical properties of 1 consisting of donor and acceptor units were investigated by the solvation effect. Changing from polar to non-polar solvent increased the solvent interaction; both the excitation and emission spectra were shifted to shorter wavelength and intensity decreased through taking advantage of twisted intramolecular charge transfer (TICT) and self-association fluorescence emission. Moreover, the red-shift and quenching in protic solvent were caused by the excited-state hydrogen bond strengthening effect. The density functional theory (DFT) and time dependent density functional theory (TDDFT) were used to obtain the most stable structure, electronic excitation energy, dipole moments and charge distribution. The AIE mechanism of 1 with casein micelle was due to 1 docked in the hydrophobic cavity between sub-micelles and bound with amino acid residues, resulting in the aggregation of 1 on the casein micelle surface and emission enhancement, based on which, a novel casein assay method was developed. The proposed method exhibited a good linear range from 0.1 to 10.5 μg mL{sup −1}, with the detection limit of 3.0 ng mL{sup −1}. Satisfactory reproducibility, reversibility and a short response time were realized. This method was applied for the determination of casein in milk powder samples, avoiding the interferences from other components and illegal additives in milk. -- Highlights: • A water-soluble 1,8-naphthalimide-based fluorescent probe 1 was synthesized. • Photophysical characterization of 1 was studied. • Aggregation induced emission enhancement of 1 with casein was investigated. • A novel casein quantification method was developed.

  18. Control and Virtual Reality Simulation of Tendon Driven Mechanisms

    International Nuclear Information System (INIS)

    Londi, Fabio; Pennestri, Ettore; Valentini, Pier Paolo; Vita, Leonardo

    2004-01-01

    In this paper the authors present a control strategy for tendon driven mechanisms. The aim of the control system is to find the correct torques which the motors have to exert to make the end effector describe a specific trajectory. In robotic assemblies this problem is often solved with closed loop algorithm, but here a simpler method, based on a open loop strategy, is developed. The difficulties in the actuation are in keeping the belt tight during all working conditions. So an innovative solution of this problem is presented here. This methodology can be easily applied in real time monitoring or very fast operations. For this reason several virtual reality simulations, developed using codes written in Virtual Reality Markup Language, are also presented. This approach is very efficient because it requires a very low cpu computation time, small size files, and the manipulator can be easily put into different simulated scenarios

  19. Tracking control mechanisms for positioning automatic CRD exchanger

    International Nuclear Information System (INIS)

    Koizumi, Akira; Takada, Satoshi.

    1984-01-01

    Purpose: To enable completely automatic positioning for the automatic CRD (control rod drives) exchanger, as well as shorten the time for the exchanging operation and save the operator's labour. Constitution: Images of a target attached to the lower flange face of CRD are picked up by a fiber scope mounted to a mounting head. The images are converted through I.T.V. into electrical signals, passed through a cable and then sent to a pattern recognition mechanism. The position for the images of the target is calculated and the calculated position is sent to a drive control section, where the position for the images of the target is compared with a reference position for the images (exactly aligned position) and the moving amount of the mounting head is calculated to move the driving section and thereby complete the positioning. (Kawakami, Y.)

  20. Uranium dioxide sintering Kinetics and mechanisms under controlled oxygen potentials

    International Nuclear Information System (INIS)

    Freitas, C.T. de.

    1980-06-01

    The initial, intermediate, and final sintering stages of uranium dioxide were investigated as a function of stoichiometry and temperature by following the kinetics of the sintering reaction. Stoichiometry was controlled by means of the oxygen potential of the sintering atmosphere, which was measured continuously by solid-state oxygen sensors. Included in the kinetic study were microspheres originated from UO 2 gels and UO 2 pellets produced by isostatic pressing ceramic grade powders. The microspheres sintering behavior was examined using hot-stage microscopy and a specially designed high-temperature, controlled atmosphere furnace. This same furnace was employed as part of an optical dilatometer, which was utilized in the UO 2 pellet sintering investigations. For controlling the deviations from stoichiometry during heat treatment, the oxygen partial pressure in the sintering atmosphere was varied by passing the gas through a Cu-Ti-Cu oxygen trap. The trap temperature determined the oxygen partial pressure of the outflowing mixture. Dry hydrogen was also used in some of the UO sub(2+x) sintering experiments. The determination of diametrial shrinkages and sintering indices was made utilizing high-speed microcinematography and ultra-microbalance techniques. It was observed that the oxygen potential has a substantial influence on the kinetics of the three sintering stages. The control of the sintering atmosphere oxygen partial pressure led to very fast densification of UO sub(2+x). Values in the interval 95.0 to 99.5% of theoretical density were reached in less than one minute. Uranium volume diffusion is the dominant mechanism in the initial and intermediate sintering stages. For the final stage, uranium grain boundary diffusion was found to be the main sintering mechanism. (Author) [pt

  1. Self-actuation type electromagnet for control rod retaining mechanism

    International Nuclear Information System (INIS)

    Saito, Makoto; Gunji, Minoru.

    1989-01-01

    The present invention concerns a self-actuation type electromagnet for automatically inserting a control rod into a reactor core for the reactor scram upon occurrence of abnormality in FBR type reactors, etc. That is, a mechanism for preventing scorching is disposed to an attracting portion of a split type core thereby enabling reliable detachment of a control rod. For this purpose, less scorching material is embedded to the attracting portion between each of the core portions, with the surface being slightly protruded. In such an attracting portion, a fine gap is formed between each of the core portions by the contact of less scorching materials. Further, the scorching material is embedded into a metal ring, which is screw-coupled to one of the core portions such that the position is adjustable in the direction of the control rod. Further, the less scorching material is made of alumina. As a result, the attracting portion is neither scorched or fused even when it is used for a long period of time in liquid sodium at high temperature. Therefore, when the electromagnet loses the attracting force, the control rod drops surely. (I.S.)

  2. Central chemoreceptors and neural mechanisms of cardiorespiratory control

    Directory of Open Access Journals (Sweden)

    T.S. Moreira

    2011-09-01

    Full Text Available The arterial partial pressure (P CO2 of carbon dioxide is virtually constant because of the close match between the metabolic production of this gas and its excretion via breathing. Blood gas homeostasis does not rely solely on changes in lung ventilation, but also to a considerable extent on circulatory adjustments that regulate the transport of CO2 from its sites of production to the lungs. The neural mechanisms that coordinate circulatory and ventilatory changes to achieve blood gas homeostasis are the subject of this review. Emphasis will be placed on the control of sympathetic outflow by central chemoreceptors. High levels of CO2 exert an excitatory effect on sympathetic outflow that is mediated by specialized chemoreceptors such as the neurons located in the retrotrapezoid region. In addition, high CO2 causes an aversive awareness in conscious animals, activating wake-promoting pathways such as the noradrenergic neurons. These neuronal groups, which may also be directly activated by brain acidification, have projections that contribute to the CO2-induced rise in breathing and sympathetic outflow. However, since the level of activity of the retrotrapezoid nucleus is regulated by converging inputs from wake-promoting systems, behavior-specific inputs from higher centers and by chemical drive, the main focus of the present manuscript is to review the contribution of central chemoreceptors to the control of autonomic and respiratory mechanisms.

  3. Neural mechanisms of attentional control in mindfulness meditation

    Directory of Open Access Journals (Sweden)

    Peter eMalinowski

    2013-02-01

    Full Text Available The scientific interest in meditation and mindfulness practice has recently seen an unprecedented surge. After an initial phase of presenting beneficial effects of mindfulness practice in various domains, research is now seeking to unravel the underlying psychological and neurophysiological mechanisms. Advances in understanding these processes are required for improving and fine-tuning mindfulness-based interventions that target specific conditions such as eating disorders or attention deficit hyperactivity disorders. This review presents a theoretical framework that emphasizes the central role of attentional control mechanisms in the development of mindfulness skills. It discusses the phenomenological level of experience during meditation, the different attentional functions that are involved, and relates these to the brain networks that subserve these functions. On the basis of currently available empirical evidence specific processes as to how attention exerts its positive influence are considered and it is concluded that meditation practice appears to positively impact attentional functions by improving resource allocation processes. As a result, attentional resources are allocated more fully during early processing phases which subsequently enhance further processing. Neural changes resulting from a pure form of mindfulness practice that is central to most mindfulness programs are considered from the perspective that they constitute a useful reference point for future research. Furthermore, possible interrelations between the improvement of attentional control and emotion regulation skills are discussed.

  4. Modeling Human Error Mechanism for Soft Control in Advanced Control Rooms (ACRs)

    International Nuclear Information System (INIS)

    Aljneibi, Hanan Salah Ali; Ha, Jun Su; Kang, Seongkeun; Seong, Poong Hyun

    2015-01-01

    To achieve the switch from conventional analog-based design to digital design in ACRs, a large number of manual operating controls and switches have to be replaced by a few common multi-function devices which is called soft control system. The soft controls in APR-1400 ACRs are classified into safety-grade and non-safety-grade soft controls; each was designed using different and independent input devices in ACRs. The operations using soft controls require operators to perform new tasks which were not necessary in conventional controls such as navigating computerized displays to monitor plant information and control devices. These kinds of computerized displays and soft controls may make operations more convenient but they might cause new types of human error. In this study the human error mechanism during the soft controls is studied and modeled to be used for analysis and enhancement of human performance (or human errors) during NPP operation. The developed model would contribute to a lot of applications to improve human performance (or reduce human errors), HMI designs, and operators' training program in ACRs. The developed model of human error mechanism for the soft control is based on assumptions that a human operator has certain amount of capacity in cognitive resources and if resources required by operating tasks are greater than resources invested by the operator, human error (or poor human performance) is likely to occur (especially in 'slip'); good HMI (Human-machine Interface) design decreases the required resources; operator's skillfulness decreases the required resources; and high vigilance increases the invested resources. In this study the human error mechanism during the soft controls is studied and modeled to be used for analysis and enhancement of human performance (or reduction of human errors) during NPP operation

  5. Modeling Human Error Mechanism for Soft Control in Advanced Control Rooms (ACRs)

    Energy Technology Data Exchange (ETDEWEB)

    Aljneibi, Hanan Salah Ali [Khalifa Univ., Abu Dhabi (United Arab Emirates); Ha, Jun Su; Kang, Seongkeun; Seong, Poong Hyun [KAIST, Daejeon (Korea, Republic of)

    2015-10-15

    To achieve the switch from conventional analog-based design to digital design in ACRs, a large number of manual operating controls and switches have to be replaced by a few common multi-function devices which is called soft control system. The soft controls in APR-1400 ACRs are classified into safety-grade and non-safety-grade soft controls; each was designed using different and independent input devices in ACRs. The operations using soft controls require operators to perform new tasks which were not necessary in conventional controls such as navigating computerized displays to monitor plant information and control devices. These kinds of computerized displays and soft controls may make operations more convenient but they might cause new types of human error. In this study the human error mechanism during the soft controls is studied and modeled to be used for analysis and enhancement of human performance (or human errors) during NPP operation. The developed model would contribute to a lot of applications to improve human performance (or reduce human errors), HMI designs, and operators' training program in ACRs. The developed model of human error mechanism for the soft control is based on assumptions that a human operator has certain amount of capacity in cognitive resources and if resources required by operating tasks are greater than resources invested by the operator, human error (or poor human performance) is likely to occur (especially in 'slip'); good HMI (Human-machine Interface) design decreases the required resources; operator's skillfulness decreases the required resources; and high vigilance increases the invested resources. In this study the human error mechanism during the soft controls is studied and modeled to be used for analysis and enhancement of human performance (or reduction of human errors) during NPP operation.

  6. Analysis of Noise Mechanisms in Cell-Size Control.

    Science.gov (United States)

    Modi, Saurabh; Vargas-Garcia, Cesar Augusto; Ghusinga, Khem Raj; Singh, Abhyudai

    2017-06-06

    At the single-cell level, noise arises from multiple sources, such as inherent stochasticity of biomolecular processes, random partitioning of resources at division, and fluctuations in cellular growth rates. How these diverse noise mechanisms combine to drive variations in cell size within an isoclonal population is not well understood. Here, we investigate the contributions of different noise sources in well-known paradigms of cell-size control, such as adder (division occurs after adding a fixed size from birth), sizer (division occurs after reaching a size threshold), and timer (division occurs after a fixed time from birth). Analysis reveals that variation in cell size is most sensitive to errors in partitioning of volume among daughter cells, and not surprisingly, this process is well regulated among microbes. Moreover, depending on the dominant noise mechanism, different size-control strategies (or a combination of them) provide efficient buffering of size variations. We further explore mixer models of size control, where a timer phase precedes/follows an adder, as has been proposed in Caulobacter crescentus. Although mixing a timer and an adder can sometimes attenuate size variations, it invariably leads to higher-order moments growing unboundedly over time. This results in a power-law distribution for the cell size, with an exponent that depends inversely on the noise in the timer phase. Consistent with theory, we find evidence of power-law statistics in the tail of C. crescentus cell-size distribution, although there is a discrepancy between the observed power-law exponent and that predicted from the noise parameters. The discrepancy, however, is removed after data reveal that the size added by individual newborns in the adder phase itself exhibits power-law statistics. Taken together, this study provides key insights into the role of noise mechanisms in size homeostasis, and suggests an inextricable link between timer-based models of size control and

  7. Respiratory mechanics in infants with severe bronchiolitis on controlled mechanical ventilation.

    Science.gov (United States)

    Cruces, Pablo; González-Dambrauskas, Sebastián; Quilodrán, Julio; Valenzuela, Jorge; Martínez, Javier; Rivero, Natalia; Arias, Pablo; Díaz, Franco

    2017-10-06

    Analysis of respiratory mechanics during mechanical ventilation (MV) is able to estimate resistive, elastic and inertial components of the working pressure of the respiratory system. Our aim was to discriminate the components of the working pressure of the respiratory system in infants on MV with severe bronchiolitis admitted to two PICU's. Infants younger than 1 year old with acute respiratory failure caused by severe bronchiolitis underwent neuromuscular blockade, tracheal intubation and volume controlled MV. Shortly after intubation studies of pulmonary mechanics were performed using inspiratory and expiratory breath hold. The maximum inspiratory and expiratory flow (QI and QE) as well as peak inspiratory (PIP), plateau (PPL) and total expiratory pressures (tPEEP) were measured. Inspiratory and expiratory resistances (RawI and RawE) and Time Constants (K TI and K TE ) were calculated. We included 16 patients, of median age 2.5 (1-5.8) months. Bronchiolitis due to respiratory syncytial virus was the main etiology (93.8%) and 31.3% had comorbidities. Measured respiratory pressures were PIP 29 (26-31), PPL 24 (20-26), tPEEP 9 [8-11] cmH2O. Elastic component of the working pressure was significantly higher than resistive and both higher than threshold (tPEEP - PEEP) (P mechanics of infants with severe bronchiolitis receiving MV shows that the elastic component of the working pressure of the respiratory system is the most important. The elastic and resistive components in conjunction with flow profile are characteristic of restrictive diseases. A better understanding of lung mechanics in this group of patients may lead to change the traditional ventilatory approach to severe bronchiolitis.

  8. Chemo-mechanical control of neural stem cell differentiation

    Science.gov (United States)

    Geishecker, Emily R.

    Cellular processes such as adhesion, proliferation, and differentiation are controlled in part by cell interactions with the microenvironment. Cells can sense and respond to a variety of stimuli, including soluble and insoluble factors (such as proteins and small molecules) and externally applied mechanical stresses. Mechanical properties of the environment, such as substrate stiffness, have also been suggested to play an important role in cell processes. The roles of both biochemical and mechanical signaling in fate modification of stem cells have been explored independently. However, very few studies have been performed to study well-controlled chemo-mechanotransduction. The objective of this work is to design, synthesize, and characterize a chemo-mechanical substrate to encourage neuronal differentiation of C17.2 neural stem cells. In Chapter 2, Polyacrylamide (PA) gels of varying stiffnesses are functionalized with differing amounts of whole collagen to investigate the role of protein concentration in combination with substrate stiffness. As expected, neurons on the softest substrate were more in number and neuronal morphology than those on stiffer substrates. Neurons appeared locally aligned with an expansive network of neurites. Additional experiments would allow for statistical analysis to determine if and how collagen density impacts C17.2 differentiation in combination with substrate stiffness. Due to difficulties associated with whole protein approaches, a similar platform was developed using mixed adhesive peptides, derived from fibronectin and laminin, and is presented in Chapter 3. The matrix elasticity and peptide concentration can be individually modulated to systematically probe the effects of chemo-mechanical signaling on differentiation of C17.2 cells. Polyacrylamide gel stiffness was confirmed using rheological techniques and found to support values published by Yeung et al. [1]. Cellular growth and differentiation were assessed by cell counts

  9. Electrically-induced muscle fatigue affects feedforward mechanisms of control.

    Science.gov (United States)

    Monjo, F; Forestier, N

    2015-08-01

    To investigate the effects of focal muscle fatigue induced by electromyostimulation (EMS) on Anticipatory Postural Adjustments (APAs) during arm flexions performed at maximal velocity. Fifteen healthy subjects performed self-paced arm flexions at maximal velocity before and after the completion of fatiguing electromyostimulation programs involving the medial and anterior deltoids and aiming to degrade movement peak acceleration. APA timing and magnitude were measured using surface electromyography. Following muscle fatigue, despite a lower mechanical disturbance evidenced by significant decreased peak accelerations (-12%, pcontrol trials (p>.11 for all analyses). The fatigue signals evoked by externally-generated contractions seem to be gated by the Central Nervous System and result in postural strategy changes which aim to increase the postural safety margin. EMS is widely used in rehabilitation and training programs for its neuromuscular function-related benefits. However and from a motor control viewpoint, the present results show that the use of EMS can lead to acute inaccuracies in predictive motor control. We propose that clinicians should investigate the chronic and global effects of EMS on motor control. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  10. Neural mechanisms of interference control in working memory capacity.

    Science.gov (United States)

    Bomyea, Jessica; Taylor, Charles T; Spadoni, Andrea D; Simmons, Alan N

    2018-02-01

    The extent to which one can use cognitive resources to keep information in working memory is known to rely on (1) active maintenance of target representations and (2) downregulation of interference from irrelevant representations. Neurobiologically, the global capacity of working memory is thought to depend on the prefrontal and parietal cortices; however, the neural mechanisms involved in controlling interference specifically in working memory capacity tasks remain understudied. In this study, 22 healthy participants completed a modified complex working memory capacity task (Reading Span) with trials of varying levels of interference control demands while undergoing functional MRI. Neural activity associated with interference control demands was examined separately during encoding and recall phases of the task. Results suggested a widespread network of regions in the prefrontal, parietal, and occipital cortices, and the cingulate and cerebellum associated with encoding, and parietal and occipital regions associated with recall. Results align with prior findings emphasizing the importance of frontoparietal circuits for working memory performance, including the role of the inferior frontal gyrus, cingulate, occipital cortex, and cerebellum in regulation of interference demands. © 2017 Wiley Periodicals, Inc.

  11. Metallurgical Mechanisms Controlling Mechanical Properties of Aluminum Alloy 2219 Produced By Electron Beam Freeform Fabrication

    Science.gov (United States)

    Domack, Marcia S.; Taminger, Karen M. B.; Begley, Matthew

    2006-01-01

    The electron beam freeform fabrication (EBF3) layer-additive manufacturing process has been developed to directly fabricate complex geometry components. EBF3 introduces metal wire into a molten pool created on the surface of a substrate by a focused electron beam. Part geometry is achieved by translating the substrate with respect to the beam to build the part one layer at a time. Tensile properties have been demonstrated for electron beam deposited aluminum and titanium alloys that are comparable to wrought products, although the microstructures of the deposits exhibit features more typical of cast material. Understanding the metallurgical mechanisms controlling mechanical properties is essential to maximizing application of the EBF3 process. In the current study, mechanical properties and resulting microstructures were examined for aluminum alloy 2219 fabricated over a range of EBF3 process variables. Material performance was evaluated based on tensile properties and results were compared with properties of Al 2219 wrought products. Unique microstructures were observed within the deposited layers and at interlayer boundaries, which varied within the deposit height due to microstructural evolution associated with the complex thermal history experienced during subsequent layer deposition. Microstructures exhibited irregularly shaped grains, typically with interior dendritic structures, which were described based on overall grain size, morphology, distribution, and dendrite spacing, and were correlated with deposition parameters. Fracture features were compared with microstructural elements to define fracture paths and aid in definition of basic processing-microstructure-property correlations.

  12. NIR dual luminescence from an extended porphyrin. Spectroscopy, photophysics and theory.

    Science.gov (United States)

    Gourlaouen, Christophe; Daniel, Chantal; Durola, Fabien; Frey, Julien; Heitz, Valérie; Sauvage, Jean-Pierre; Ventura, Barbara; Flamigni, Lucia

    2014-05-22

    Spectroscopic and photophysical properties of an extended Zn porphyrin with fused bis(tetraazaanthracene) arms including a 2,9-diphenyl-1,10-phenanthroline incorporated in a polyether macrocycle are investigated in solvents of different polarity pointing to the presence of two emitting singlet excited states. The absorption and emission features are identified and ascribed, on the basis of solvent polarity dependence, to a π-π* and to a charge transfer (CT) state, respectively. Whereas the intraligand π-π* transition is assigned to the intense absorption observed at 442-455 nm, the CT states contribute to the bands at 521-525 nm and 472-481 nm. The theoretical analysis of the absorption spectrum confirms the presence of two strong bands centered at 536 and 437 nm corresponding to CT and π-π* states, respectively. Weak CT transitions are calculated at 657 and 486 nm. Two emission maxima are observed in toluene at 724 nm from a (1)π-π* state and at 800 nm from a (1)CT state, respectively. (1)CT bands shift bathochromically by increasing the solvent polarity whereas the energy of the (1)π-π band is less affected. Likewise, the emission yield and lifetime associated with the low energy (1)CT band are strongly affected by solvent polarity. This is rationalized by a (1)π-π* → (1)CT internal conversion driven by solvent polarity, this process being competitive with the (1)π-π* to ground state deactivation channel. Time resolved absorption spectra indicate the presence of two triplet states, a short-lived one (nanoseconds range) and a longer lived one (hundreds of microsecond range) ascribed to a (3)π-π* and a (3)CT, respectively. For them, a conversion mechanism similar to that of the singlet excited states is suggested.

  13. Photophysical and photochemical properties of Bauhinia megalandra (Caesalpinaceae) extracts as new PDT photosensitizer

    Science.gov (United States)

    Vargas Tovar, Franklin R.; Rivas, C.; Estrada, O.; Marcano O., Aristides A.; Echevarria, Lorenzo; Diaz, Yrene; Alexander, I.; Rodriguez, L.; Padron, L.; Rivera, I. R.

    2004-10-01

    Recently new photosensitizers, chlorophyll "a and b" derivatives, for photodynamic therapy (PDT) have been presented. It already passed complete pre-clinical investigations. This prompted us to carry out an extensive study of photophysical properties of chlorine derivatives, important both for optimization of their clinic applications and for study of mechanisms of chlorine PDT&. The fresh leaves of Bauhinia megalandra (Caesalpinaceae) were extracted with methanol by percolation, and re-extract with a mixture of methanol-water (1:1), the insoluble fraction was then separated by column chromatography [RP18/hexane-ethylacetate (9:1)] to obtain four fractions named 1 to 4. These compounds were identified by NMR data. We found that 3 and 4 efficiently generates singlet oxygen when irradiated with visible light. Detection of the singlet oxygen was fulfilled by its reaction with histidine and detected by bleaching p-nitrosodimethylaniline under 440 nm irradiation. The quantum yields of singlet oxygen determined by us were 0.088 (1), 0.151 (2), 0.219 (3) and 0.301 (4). We measured absorption and fluorescence spectra of compounds 1 to 4 (Mg-chlorophyll-a, Pheophytin, Mg-chlorophyll-b and chlorophyll-b respectively) in different media and in aqueous solutions of human serum albumin. The association constant of the compounds 1, 2, 3 and 4 in the presence of HSA were estimated. The binding and quenching studies suggest that only 1 and 3 may serve as a useful fluorescence probe for structure/function studies of different chlorophyll binding proteins. No photoinduced binding was observed after irradiation by all the studied compounds in presence of human serum albumin.

  14. New naphthalene polyimide with unusual molar absorption coefficient and excited state properties: Synthesis, photophysics and electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ozser, Mustafa E. [Girne American University, Faculty of Engineering and Architecture, Department of Industrial Engineering, Girne, North Cyprus (Cyprus); Yucekan, Ilke; Bodapati, Jagadeesh B. [Eastern Mediterranean University, Faculty of Arts and Sciences, Department of Chemistry, Famagusta, North Cyprus (Cyprus); Icil, Huriye, E-mail: huriye.icil@emu.edu.tr [Eastern Mediterranean University, Faculty of Arts and Sciences, Department of Chemistry, Famagusta, North Cyprus (Cyprus)

    2013-11-15

    A high molecular weight 1,4,5,8-naphthalene polyimide (ENPI) by one-step polycondensation mechanism and for comparison its monomeric diimide (ENDI) were synthesized; the photophysical and electrochemical properties were studied in detail for ENPI. Monomer has shown unusual insolubility so that the characterization proven to be difficult, whereas ENPI has shown better solubility. The molecular weight data obtained by GPC for the polymer were M{sub n}=8240 and M{sub w}=34,000 g mol{sup −1} respectively with a polydispersity of 4.13. The polyimide exhibited outstandingly high molar absorption coefficients as 599,000, 1,021,000, and 972,700 M{sup −1} cm{sup −1}, which is first time reported in literature for the characteristic 0–2, 0–1, and 0–0 electronic transitions, respectively. ENPI showed concentration dependent and red shifted excimer emission in 1,1,2,2-tetrachloroethane (TCE). The polymer has undergone multielectron reductions in CHCl{sub 3} solution below 100 mV s{sup −1} scan rates which merged into two reversible one-electron reduction peaks at higher scan rates. In solid-state, similar scan rate dependent reduction peaks were noticed. The LUMO, HOMO and optical band gap values obtained for ENPI were −3.73, −6.91, and 3.18 eV respectively. ENDI polymer with striking features has great potential as new sensitizer for efficient dye sensitized organic cells. Highlights: • A high molecular weight naphthalene polyimide was synthesized (M{sub w}=34,000 g mol{sup −1}). • The oligoether polyimide exhibited outstanding molar absorptivity (972,700 M{sup −1} cm{sup −1}). • A red shifted excimer emission has been observed. • The polymer has undergone multielectron reductions.

  15. Photophysical Properties of Novel Organic, Inorganic, and Hybrid Semiconductor Materials

    Science.gov (United States)

    Chang, Angela Yenchi

    For the past 200 years, novel materials have driven technological progress, and going forward these advanced materials will continue to deeply impact virtually all major industrial sectors. Therefore, it is vital to perform basic and applied research on novel materials in order to develop new technologies for the future. This dissertation describes the results of photophysical studies on three novel materials with electronic and optoelectronic applications, namely organic small molecules DTDCTB with C60 and C70, colloidal indium antimonide (InSb) nanocrystals, and an organic-inorganic hybrid perovskite with the composition CH3NH3PbI 3-xClx, using transient absorption (TA) and photoluminescence (PL) spectroscopy. In chapter 2, we characterize the timescale and efficiency of charge separation and recombination in thin film blends comprising DTDCTB, a narrow-band gap electron donor, and either C60 or C70 as an electron acceptor. TA and time-resolved PL studies show correlated, sub-picosecond charge separation times and multiple timescales of charge recombination. Our results indicate that some donors fail to charge separate in donor-acceptor mixed films, which suggests material manipulations may improve device efficiency. Chapter 3 describes electron-hole pair dynamics in strongly quantum-confined, colloidal InSb nanocrystal quantum dots. For all samples, TA shows a bleach feature that, for several picoseconds, dramatically red-shifts prior to reaching a time-independent position. We suggest this unusual red-shift relates transient population flow through two energetically comparable conduction band states. From pump-power-dependent measurements, we also determine biexciton lifetimes. In chapter 4, we examine carrier dynamics in polycrystalline methylammonium lead mixed halide perovskite (CH3NH3PbI3-xCl x) thin films as functions of temperature and photoexcitation wavelength. At room temperature, the long-lived TA signals stand in contrast to PL dynamics, where the

  16. A class of fluorescent heterocyclic dyes revisited: photophysics, structure, and solvent effects

    DEFF Research Database (Denmark)

    Zhu, Lianjie; Jensen, Hans-Christian Becker; Henriksen, Lars

    2009-01-01

    The photophysical behavior of a series of 2-methylthio-5-(Z-carbonyl)thieno-[3,4-e]-3,4-dihydro-1,2,3-triazine-4-ones was investigated by absorption and emission spectroscopy in a range of solvents representing a systematic variation in polarity, polarizability, as well as hydrogen bond donating ...

  17. New electroluminescent carbazole-containing conjugated polymer: synthesis, photophysics, and electroluminescence

    Czech Academy of Sciences Publication Activity Database

    Cimrová, Věra; Ulbricht, C.; Dzhabarov, Vagif; Výprachtický, Drahomír; Egbe, D. A. M.

    2014-01-01

    Roč. 55, č. 24 (2014), s. 6220-6226 ISSN 0032-3861 R&D Projects: GA ČR GAP106/12/0827; GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : carbazole-containing conjugated polymer * synthesis * photophysics and electroluminescence Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.562, year: 2014

  18. Photo-physics study of an hydroxy-quinoline derivative as inhibitor of Pim-1 kinase

    DEFF Research Database (Denmark)

    Lamhasni, T.; Aitlyazidi, S.; Hnach, M.

    2013-01-01

    The photophysical properties of the antiviral 7-nicotinoyl-styrylquinoline (MB96) were investigated by means of UV-Vis linear dichroism (LD) spectroscopy on molecular samples aligned in stretched polyvinylalcohol (PVA), supported by Time Dependent Density Functional Theory (TD-DFT) calculations...

  19. Photophysics and photochemistry of Riboflavin-induced corneal Cross-Linking

    DEFF Research Database (Denmark)

    Breitenbach, Thomas

    In this talk, we will describe general pathways involved in the photophysics of a photosensitized process, which can lead to crosslinking due to light excitation of Riboflavin in the cornea. Furthermore, we will show the contribution of singlet molecular oxygen O2(a1Δg) to this phenomena and show...

  20. Photophysical and physicochemical studies of rare earths complexes formed with calyx(n)arenes

    International Nuclear Information System (INIS)

    Ramirez, F.M.; Varbanov, S.; Corine, C.; Muller, G.; Fatin-Rouge, N.; Scopelliti, R.; Bunzli J, C.G.

    2001-01-01

    In this work, some of the photophysical and physicochemical properties are presented which are observed in the rare earths complexes that are formed with diverse functionalized calyx(n)arenes receptors where n=4-6 designed with predetermined properties and synthesized by own methods. (Author)

  1. Photophysics of organometallic platinum(II) derivatives of the diketopyrrolopyrrole chromophore

    KAUST Repository

    Goswami, Subhadip

    2014-12-18

    A pair of diketopyrrolopyrrole (DPP) chromophores that are end-functionalized with platinum containing "auxochromes" were subjected to electrochemical and photophysical study. The chromophores contain either platinum acetylide or ortho-metalated 2-thienylpyridinyl(platinum) end-groups (DPP-Pt(CC) and DPP-Pt(acac), respectively). The ground state redox potentials of the chromophores were determined by solution electrochemistry, and the HOMO and LUMO levels were estimated. The chromophores\\' photophysical properties were characterized by absorption, photoluminescence, and time-resolved absorption spectroscopy on time scales from sub-picoseconds to microseconds. Density functional theory (DFT) computations were performed to understand the molecular orbitals involved in both the singlet and triplet excited state photophysics. The results reveal that in both platinum DPP derivatives the organometallic auxochromes have a significant effect on the chromophores\\' photophysics. The most profound effect is a reduction in the fluorescence yields accompanied by enhanced triplet yields due to spin-orbit coupling induced by the metal centers. The effects are most pronounced in DPP-Pt(acac), indicating that the orthometalated platinum auxochrome is able to induce spin-orbital coupling to a greater extent compared to the platinum acetylide units. (Figure Presented).

  2. Simulation of some dynamical aspects of the photophysics of dye molecules encapsulated in a dendrimer

    Energy Technology Data Exchange (ETDEWEB)

    Teobaldi, Gilberto [Dipartimento di Chimica ' G. Ciamician' , Universita di Bologna, Via F. Selmi 2, Bologna I-40126 (Italy); Zerbetto, Francesco [Dipartimento di Chimica ' G. Ciamician' , Universita di Bologna, Via F. Selmi 2, Bologna I-40126 (Italy)]. E-mail: francesco.zerbetto@unibo.it

    2005-03-15

    We use a combination of molecular dynamics and quantum chemical calculations to investigate the photophysics of Eosin Y encapsulated in a fourth generation of poly-propylene amine dendrimer functionalized in the periphery with dansyl units. Once in contact with the macromolecule, the guests display a double exponential decay of the excited states that is reproduced by the present model.

  3. Simulation of some dynamical aspects of the photophysics of dye molecules encapsulated in a dendrimer

    International Nuclear Information System (INIS)

    Teobaldi, Gilberto; Zerbetto, Francesco

    2005-01-01

    We use a combination of molecular dynamics and quantum chemical calculations to investigate the photophysics of Eosin Y encapsulated in a fourth generation of poly-propylene amine dendrimer functionalized in the periphery with dansyl units. Once in contact with the macromolecule, the guests display a double exponential decay of the excited states that is reproduced by the present model

  4. Photophysics of organometallic platinum(II) derivatives of the diketopyrrolopyrrole chromophore

    KAUST Repository

    Goswami, Subhadip; Winkel, Russell W.; Alarousu, Erkki; Ghiviriga, Ion; Mohammed, Omar F.; Schanze, Kirk S.

    2014-01-01

    A pair of diketopyrrolopyrrole (DPP) chromophores that are end-functionalized with platinum containing "auxochromes" were subjected to electrochemical and photophysical study. The chromophores contain either platinum acetylide or ortho-metalated 2-thienylpyridinyl(platinum) end-groups (DPP-Pt(CC) and DPP-Pt(acac), respectively). The ground state redox potentials of the chromophores were determined by solution electrochemistry, and the HOMO and LUMO levels were estimated. The chromophores' photophysical properties were characterized by absorption, photoluminescence, and time-resolved absorption spectroscopy on time scales from sub-picoseconds to microseconds. Density functional theory (DFT) computations were performed to understand the molecular orbitals involved in both the singlet and triplet excited state photophysics. The results reveal that in both platinum DPP derivatives the organometallic auxochromes have a significant effect on the chromophores' photophysics. The most profound effect is a reduction in the fluorescence yields accompanied by enhanced triplet yields due to spin-orbit coupling induced by the metal centers. The effects are most pronounced in DPP-Pt(acac), indicating that the orthometalated platinum auxochrome is able to induce spin-orbital coupling to a greater extent compared to the platinum acetylide units. (Figure Presented).

  5. Analysis of the photophysical properties of zearalenone using density functional theory

    Science.gov (United States)

    The intrinsic photophysical properties of the resorcylic acid moiety of zearalenone offer a convenient label free method to determine zearalenone levels in contaminated agricultural products. Density functional theory and steady-state fluorescence methods were applied to investigate the role of stru...

  6. Development of embedded Control System for Control and Safety Rod Drive Mechanisms (CSRDMs) of PFBR

    International Nuclear Information System (INIS)

    Kameswari, K.; Palanisami, K.; Thirugnana Murthy, D.; Murali, N.; Satyamurty, S.A.V.

    2013-01-01

    Prototype Fast Breeder Reactor (PFBR), a 500 MWe, Sodium cooled, fast breeder reactor is nearing completion at Kalpakkam, Tamil Nadu. PFBR has two independent, fast acting and diverse shutdown systems, one with nine Control and Safety Rods (CSRs) and another with three Diverse Safety Rods (DSRs), with independent driving mechanisms called CSRDMs and DSRDMs respectively. This paper deals with the development of Real Time Computer based Control system for controlling nine CSRDMs with model based software development environment - SCADE (Safety Critical Application Development Environment). (author)

  7. Mechanism of anterior-posterior polarity control in planarians

    Energy Technology Data Exchange (ETDEWEB)

    Lange, C.S.; Steele, V.E.

    1978-01-01

    The substance which inhibits brain formation in the regenerating planarian Dugesia etrusca was found to be a large molecule, at least in part protein, which electrophoreses as an electronegative moiety in pH 6.8 buffer. A model is presented, based on this finding and previous studies, which proposes an electrochemical mechanism for the control of polarity and possibly for the maintenance of tissue organization in planarians. It is proposed that a bioelectric field exists and moves the electronegative brain-inhibiting substance in a posterior direction, establishing polarity. This model explains the polarity reversal experiments using external fields and many of the previously unexplained classical planarian experiments. Data are presented demonstrating the existence, magnitude, and polarity of this bioelectric field, which is not greatly altered upon decapitation, all in accord with predictions of the model.

  8. The inner-city Skater Facility - playground or control mechanism?

    DEFF Research Database (Denmark)

    Gravesen, David Thore

    2016-01-01

    special Social services, School and Police unit), that observe, mingle and socialize at the facility. The social workers affiliated with the SSP understand and define their role in contradiction to the official agenda. The social workers seek to pull the young people off the street and get them to enroll......The inner-city Skater Facility - playground or control mechanism? In 2013, the municipality in Horsens, a medium-sized provincial town in Denmark, bestowed the city's children and young people a skater facility at the city's central squares. Officially, the municipality donated the facility to give...... local children and young people an opportunity to use their leisure time stimulating their bodies, having a great time with friends and other urban dwellers. The gift is accompanied by a number of (more or less camouflaged) crime prevention- and social education agendas, carried out by the SSP (a...

  9. Fuzzy logic controller for weaning neonates from mechanical ventilation.

    Science.gov (United States)

    Hatzakis, G E; Davis, G M

    2002-01-01

    Weaning from mechanical ventilation is the gradual detachment from any ventilatory support till normal spontaneous breathing can be fully resumed. To date, we have developed a fuzzy logic controller for weaning COPD adults using pressure support ventilation (PS). However, adults and newborns differ in the pathophysiology of lung disease. We therefore used our fuzzy logic-based weaning platform to develop modularized components for weaning newborns with lung disease. Our controller uses the heart rate (HR), respiratory rate (RR), tidal volume (VT) and oxygen saturation (SaO2) and their trends deltaHR/deltat, deltaVT/deltat and deltaSaO2/deltat to evaluate, respectively, the Current and Trend weaning status of the newborn. Through appropriate fuzzification of these vital signs, Current and Trend weaning status can quantitatively determine the increase/decrease in the synchronized intermittent mandatory ventilation (SIMV) setting. The post-operative weaning courses of 10 newborns, 82+/-162 days old, were assessed at 2-hour intervals for 68+/-39 days. The SIMV levels, proposed by our algorithm, were matched to those levels actually applied. For 60% of the time both values coincided. For the remaining 40%, our algorithm suggested lower SIMV support than what was applied. The Area Under the Curve for integrated ventilatory support over time was 1203+/-846 for standard ventilatory strategies and 1152+/-802 for fuzzy controller. This suggests that the algorithm, approximates the actual weaning progression, and may advocate a more aggressive strategy. Moreover, the core of the fuzzy controller facilitates adaptation for body size and diversified disease patterns and sets the premises as an infant-weaning tool.

  10. Mechanisms controlling the distribution of two invasive Bromus species

    Directory of Open Access Journals (Sweden)

    Olga Bykova

    2014-03-01

    Full Text Available In order to predict future range shifts for invasive species it is important to explore their ability to acclimate to the new environment and understand physiological and reproductive constraints controlling their distribution. My dissertation studied mechanisms by which temperature may affect the distribution of two aggressive plant invaders in North America, Bromus tectorum and Bromus rubens. I first evaluated winter freezing tolerance of Bromus species and demonstrated that the mechanism explaining their distinct northern range limits is different acquisition time of freezing tolerance. While B. rubens has a slower rate of freezing acclimation that leads to intolerance of sudden, late-autumn drops in temperature below -12°C, B. tectorum rapidly hardens and so is not impacted by the sudden onset of severe late-autumn cold. In addition, the analysis of male reproductive development and seed production showed that neither species produces seed at or above 36°C, due to complete pollen sterility, which might trigger climate-mediated range contractions at B. tectorum and B. rubens southern margins. Finally, a detailed gas-exchange analysis combined with biochemical modelling demonstrated that both species acclimate to a broad range of temperatures and photosynthetic response to temperature does not explain their current range separation.

  11. Principles of control automation of soil compacting machine operating mechanism

    Science.gov (United States)

    Anatoly Fedorovich, Tikhonov; Drozdov, Anatoly

    2018-03-01

    The relevance of the qualitative compaction of soil bases in the erection of embankment and foundations in building and structure construction is given.The quality of the compactible gravel and sandy soils provides the bearing capability and, accordingly, the strength and durability of constructed buildings.It has been established that the compaction quality depends on many external actions, such as surface roughness and soil moisture; granulometry, chemical composition and degree of elasticity of originalfilled soil for compaction.The analysis of technological processes of soil bases compaction of foreign and domestic information sources showed that the solution of such important problem as a continuous monitoring of soil compaction actual degree in the process of machine operation carry out only with the use of modern means of automation. An effective vibrodynamic method of gravel and sand material sealing for the building structure foundations for various applications was justified and suggested.The method of continuous monitoring the soil compaction by measurement of the amplitudes and frequencies of harmonic oscillations on the compactible surface was determined, which allowed to determine the basic elements of facilities of soil compacting machine monitoring system of operating, etc. mechanisms: an accelerometer, a bandpass filter, a vibro-harmonics, an on-board microcontroller. Adjustable parameters have been established to improve the soil compaction degree and the soil compacting machine performance, and the adjustable parameter dependences on the overall indexhave been experimentally determined, which is the soil compaction degree.A structural scheme of automatic control of the soil compacting machine control mechanism and theoperation algorithm has been developed.

  12. The Gas-Phase Photophysics of Eosin Y and its Maleimide Conjugate.

    Science.gov (United States)

    Daly, Steven; Kulesza, Alexander; Knight, Geoffrey; MacAleese, Luke; Antoine, Rodolphe; Dugourd, Philippe

    2016-05-26

    The use of the xanthene family of dyes as fluorescent probes in a wide range of applications has provided impetus for the studying of their photophysical properties. In particular, recent advances in gas-phase techniques such as FRET that utilize such chromophores have placed a greater importance on the characterization of these properties in the gas phase. Additionally, the use of synthetic linker chains to graft the chromophores in a site-specific manner to their target system is ubiquitous. There is, however, often limited information on how the addition of such a linker chain may affect the photophysical properties of the chromophores, which is of fundamental importance for interpretation of experimental data reliant on grafted chromophores. Here, we present data on the optical spectroscopy of different protonation states of Eosin Y, a fluorescein derivative. We compare the photophysics of Eosin Y to its maleimide conjugate, and to the thioether product of the reaction of this conjugate with cysteamine. Comparison of the mass spectra following laser irradiation shows that very different relaxation takes place upon addition of the maleimide moiety but that the photophysics of the bare chromophore are restored upon addition of cysteamine. This radical change in the photophysics is interpreted in terms of charge-transfer states, whose energy relative to the S1 ← S0 transition of the chromophore is dependent on the conjugation of the maleimide moiety. We also show that the shape of the absorption band is unchanged in the gas-phase as compared to the solution-phase, showing a maximum with a shoulder toward the blue, and examination of isotope distributions of the isolated ions show that this shoulder cannot be due to the presence of dimers. Consideration of the fluorescence emission spectrum allows a tentative assignment of the shoulder to be due to a vibrational progression with a high Franck-Condon factor.

  13. Controlled release systems containing solid dispersions: strategies and mechanisms.

    Science.gov (United States)

    Tran, Phuong Ha-Lien; Tran, Thao Truong-Dinh; Park, Jun Bom; Lee, Beom-Jin

    2011-10-01

    In addition to a number of highly soluble drugs, most new chemical entities under development are poorly water-soluble drugs generally characterized by an insufficient dissolution rate and a small absorption window, leading to the low bioavailability. Controlled-release (CR) formulations have several potential advantages over conventional dosage forms, such as providing a uniform and prolonged therapeutic effect to improve patient compliance, reducing the frequency of dosing, minimizing the number of side effects, and reducing the strength of the required dose while increasing the effectiveness of the drug. Solid dispersions (SD) can be used to enhance the dissolution rate of poorly water-soluble drugs and to sustain the drug release by choosing an appropriate carrier. Thus, a CR-SD comprises both functions of SD and CR for poorly water-soluble drugs. Such CR dosage forms containing SD provide an immediately available dose for an immediate action followed by a gradual and continuous release of subsequent doses to maintain the plasma concentration of poorly water-soluble drugs over an extended period of time. This review aims to summarize all currently known aspects of controlled release systems containing solid dispersions, focusing on the preparation methods, mechanisms of action and characterization of physicochemical properties of the system.

  14. Quality control mechanisms of protein biogenesis: proteostasis dies hard

    Directory of Open Access Journals (Sweden)

    Timothy Jan Bergmann

    2016-10-01

    Full Text Available The biosynthesis of proteins entails a complex series of chemical reactions that transform the information stored in the nucleic acid sequence into a polypeptide chain that needs to properly fold and reach its functional location in or outside the cell. It is of no surprise that errors might occur that alter the polypeptide sequence leading to a non-functional proteins or that impede delivery of proteins at the appropriate site of activity. In order to minimize such mistakes and guarantee the synthesis of the correct amount and quality of the proteome, cells have developed folding, quality control, degradation and transport mechanisms that ensure and tightly regulate protein biogenesis. Genetic mutations, harsh environmental conditions or attack by pathogens can subvert the cellular quality control machineries and perturb cellular proteostasis leading to pathological conditions. This review summarizes basic concepts of the flow of information from DNA to folded and active proteins and to the variable fidelity (from incredibly high to quite sloppy characterizing these processes. We will give particular emphasis on events that maintain or recover the homeostasis of the endoplasmic reticulum (ER, a major site of proteins synthesis and folding in eukaryotic cells. Finally, we will report on how cells can adapt to stressful conditions, how perturbation of ER homeostasis may result in diseases and how these can be treated.

  15. Dynamic environmental control mechanisms for pneumatic foil constructions

    Science.gov (United States)

    Flor, Jan-Frederik; Wu, Yupeng; Beccarelli, Paolo; Chilton, John

    2017-11-01

    Membrane and foil structures have become over the last decades an attractive alternative to conventional materials and building systems with increasing implementation in different typologies and scale. The development of transparent, light, flexible and resistant materials like Ethylene Tetrafluoroethylene (ETFE) has triggered a rethinking of the building envelope in the building industry towards lightweight systems. ETFE foil cushions have proven to fulfil the design requirements in terms of structural efficiency and aesthetic values. But the strategies to satisfy increasing demands of energy efficiency and comfort conditions are still under development. The prediction and manipulation of the thermo-optical behaviour of ETFE foil cushion structures currently remain as one of the main challenges for designers and manufacturers. This paper reviews ongoing research regarding the control of the thermo-optical performance of ETFE cushion structures and highlights challenges and possible improvements. An overview of different dynamic and responsive environmental control mechanisms for multilayer foil constructions is provided and the state of the art in building application outlined by the discussion of case studies.

  16. Multi-function magnetic jack control drive mechanism

    International Nuclear Information System (INIS)

    Bollinger, L.R.; Crawford, D.C.

    1986-01-01

    A multi-function magnetic jack control drive mechanism is described for controlling a nuclear reactor comprising: an elongate pressure housing; closely-spaced drive rods located in the pressure housing, the drive rod being connected to a reactor rod which is insertable in a reactor core; electrochemical stationary latch means which are selectively actuatable for holding a respective one of the drive rods stationary with respect to the pressure housing, the plurality of stationary latch means including at least one coil located about the pressure housing; longitudinally spaced electromechanical movable latch means, individually associated with one of the drive rods and each including a base for the drive rod associated therewith, for, when actuated, holding the associated drive rod stationary with respect to the base associated therewith, the movable latch means including an associated coil located about the pressure housing; and longitudinally spaced electromechanical lift means, individually associated with the base, for, when actuated, moving an associated base longitudinally along the pressure housing from a first position to a second position to thereby enable movement of one or more of the other drive rods longitudinally independently of the other drive rods in response to sequential and repeated operation of the electromechanical means, the lift means including an associated coil located about the pressure housing

  17. Linear and nonlinear photophysics and bioimaging of an integrin-targeting water-soluble fluorenyl probe.

    Science.gov (United States)

    Morales, Alma R; Luchita, Gheorghe; Yanez, Ciceron O; Bondar, Mykhailo V; Przhonska, Olga V; Belfield, Kevin D

    2010-06-07

    Linear photophysical characterization and two-photon absorption (2PA) properties of a new water-soluble fluorene derivative, 3-(9-(2-(2-methoxyethoxy)ethyl)-2,7-bis{3-[2-(polyethyleneglycol-550-monomethylether-1-yl)]-4-(benzo[d]thiazol-2-yl)styryl}-9H-fluoren-9-yl)propanoic acid (1), were investigated in several organic solvents and water at room temperature. A comprehensive analysis of the steady-state absorption, emission and excitation anisotropy spectra revealed electronic structures of 1, including mutual orientation of the transition dipoles, relatively weak solvatochromic effects, high fluorescence quantum yield (approximately 0.5-1.0), and strong aggregation in water. The 2PA spectra of 1 were obtained in the 600-900 nm spectral range by two-photon induced fluorescence (2PF) and open aperture Z-scan methods using femtosecond laser sources. No discrete 2PA bands were apparent and values of the corresponding 2PA cross sections monotonically increased in the short wavelength range up to 3000 GM in organic solvents and approximately 6000 GM in aqueous solution, reflecting relatively high two-photon absorptivity. The 2PA efficiency of in water increased 2-3 times relative to aprotic solvents and can be explained by cooperative electronic effects of molecular aggregates of 1 produced in aqueous media. The carboxylic acid fluorenyl probe 1 was conjugated with the cyclic peptide RGDfK. Two-photon fluorescence microscopy (2PFM) imaging of U87MG cells (and MCF-7 as control), incubated with fluorene-RGD peptide conjugate 2, demonstrated high alpha(v)beta(3) integrin selectivity, making this probe particularly attractive for integrin imaging.

  18. Molecular nucleation mechanisms and control strategies for crystal polymorph selection

    Science.gov (United States)

    van Driessche, Alexander E. S.; van Gerven, Nani; Bomans, Paul H. H.; Joosten, Rick R. M.; Friedrich, Heiner; Gil-Carton, David; Sommerdijk, Nico A. J. M.; Sleutel, Mike

    2018-04-01

    The formation of condensed (compacted) protein phases is associated with a wide range of human disorders, such as eye cataracts, amyotrophic lateral sclerosis, sickle cell anaemia and Alzheimer’s disease. However, condensed protein phases have their uses: as crystals, they are harnessed by structural biologists to elucidate protein structures, or are used as delivery vehicles for pharmaceutical applications. The physiochemical properties of crystals can vary substantially between different forms or structures (‘polymorphs’) of the same macromolecule, and dictate their usability in a scientific or industrial context. To gain control over an emerging polymorph, one needs a molecular-level understanding of the pathways that lead to the various macroscopic states and of the mechanisms that govern pathway selection. However, it is still not clear how the embryonic seeds of a macromolecular phase are formed, or how these nuclei affect polymorph selection. Here we use time-resolved cryo-transmission electron microscopy to image the nucleation of crystals of the protein glucose isomerase, and to uncover at molecular resolution the nucleation pathways that lead to two crystalline states and one gelled state. We show that polymorph selection takes place at the earliest stages of structure formation and is based on specific building blocks for each space group. Moreover, we demonstrate control over the system by selectively forming desired polymorphs through site-directed mutagenesis, specifically tuning intermolecular bonding or gel seeding. Our results differ from the present picture of protein nucleation, in that we do not identify a metastable dense liquid as the precursor to the crystalline state. Rather, we observe nucleation events that are driven by oriented attachments between subcritical clusters that already exhibit a degree of crystallinity. These insights suggest ways of controlling macromolecular phase transitions, aiding the development of protein

  19. Hybrid controller design and verification for the METIS Cold Chopper Mechanism

    NARCIS (Netherlands)

    Huisman, Robert; Jayawardhana, Bayu; Scherpen, Jacquelien M.A.

    2014-01-01

    We discuss the design and validation of a hybrid controller for the METIS Cold Chopper Mechanism (MCCD)(1). The described control strategy has been chosen to meet the stringent performance requirements of the mechanism subject to constraints on the input.

  20. Fracture mechanisms and fracture control in composite structures

    Science.gov (United States)

    Kim, Wone-Chul

    Four basic failure modes--delamination, delamination buckling of composite sandwich panels, first-ply failure in cross-ply laminates, and compression failure--are analyzed using linear elastic fracture mechanics (LEFM) and the J-integral method. Structural failures, including those at the micromechanical level, are investigated with the aid of the models developed, and the critical strains for crack propagation for each mode are obtained. In the structural fracture analyses area, the fracture control schemes for delamination in a composite rib stiffener and delamination buckling in composite sandwich panels subjected to in-plane compression are determined. The critical fracture strains were predicted with the aid of LEFM for delamination and the J-integral method for delamination buckling. The use of toughened matrix systems has been recommended for improved damage tolerant design for delamination crack propagation. An experimental study was conducted to determine the onset of delamination buckling in composite sandwich panel containing flaws. The critical fracture loads computed using the proposed theoretical model and a numerical computational scheme closely followed the experimental measurements made on sandwich panel specimens of graphite/epoxy faceskins and aluminum honeycomb core with varying faceskin thicknesses and core sizes. Micromechanical models of fracture in composites are explored to predict transverse cracking of cross-ply laminates and compression fracture of unidirectional composites. A modified shear lag model which takes into account the important role of interlaminar shear zones between the 0 degree and 90 degree piles in cross-ply laminate is proposed and criteria for transverse cracking have been developed. For compressive failure of unidirectional composites, pre-existing defects play an important role. Using anisotropic elasticity, the stress state around a defect under a remotely applied compressive load is obtained. The experimentally

  1. Self-organization, interfacial interaction and photophysical properties of gold nanoparticle complexes derived from resilin-mimetic fluorescent protein rec1-resilin.

    Science.gov (United States)

    Mayavan, Sundar; Dutta, Naba K; Choudhury, Namita R; Kim, Misook; Elvin, Christopher M; Hill, Anita J

    2011-04-01

    In this investigation we report the synthesis of optically coupled hybrid architectures based on a new biomimetic fluorescent protein rec1-resilin and nanometer-scale gold nanoparticles (AuNPs) in a one-step method using a non-covalent mode of binding protocol. The presence of uniformly distributed fluorophore sequences, -Ser(Thr)-Tyr-Gly- along the molecular structure of rec1-resilin provides significant opportunity to synthesize fluorophore-modified AuNPs bioconjugates with unique photophysical properties. The detailed analyses of the AuNP-bioconjugates, synthesized under different experimental conditions using spectroscopic, microscopic and scattering techniques demonstrate the organizational pathways and the electronic and photophysical properties of the developed AuNP-rec1-resilin bioconjugates. The calculation of the bimolecular quenching constant using the Stern-Volmer equation confirms that the dominant mechanism involved in quenching of fluorescence of rec1-resilin in the presence of AuNP is static. Photoacoustic infrared spectroscopy was employed to understand the nature of the interfacial interaction between the AuNP and rec1-resilin and its evolution with pH. In such bioconjugates the quenched emission of fluorescence by AuNP on the fluorophore moiety of rec1-resilin in the immediate vicinity of the AuNP has significant potential for fluorescence-based detection schemes, sensors and also can be incorporated into nanoparticle-based devices. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Dimensionless study on dynamics of pressure controlled mechanical ventilation system

    International Nuclear Information System (INIS)

    Shi, Yan; Niu, Jinglong; Cai, Maolin; Xu, Weiqing

    2015-01-01

    Dynamics of mechanical ventilation system can be referred in pulmonary diagnostics and treatments. In this paper, to conveniently grasp the essential characteristics of mechanical ventilation system, a dimensionless model of mechanical ventilation system is presented. For the validation of the mathematical model, a prototype mechanical ventilation system of a lung simulator is proposed. Through the simulation and experimental studies on the dimensionless dynamics of the mechanical ventilation system, firstly, the mathematical model is proved to be authentic and reliable. Secondly, the dimensionless dynamics of the mechanical ventilation system are obtained. Last, the influences of key parameters on the dimensionless dynamics of the mechanical ventilation system are illustrated. The study provides a novel method to study the dynamic of mechanical ventilation system, which can be referred in the respiratory diagnostics and treatment.

  3. Dimensionless study on dynamics of pressure controlled mechanical ventilation system

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yan; Niu, Jinglong; Cai, Maolin; Xu, Weiqing [Beihang University, Beijing (Korea, Republic of)

    2015-02-15

    Dynamics of mechanical ventilation system can be referred in pulmonary diagnostics and treatments. In this paper, to conveniently grasp the essential characteristics of mechanical ventilation system, a dimensionless model of mechanical ventilation system is presented. For the validation of the mathematical model, a prototype mechanical ventilation system of a lung simulator is proposed. Through the simulation and experimental studies on the dimensionless dynamics of the mechanical ventilation system, firstly, the mathematical model is proved to be authentic and reliable. Secondly, the dimensionless dynamics of the mechanical ventilation system are obtained. Last, the influences of key parameters on the dimensionless dynamics of the mechanical ventilation system are illustrated. The study provides a novel method to study the dynamic of mechanical ventilation system, which can be referred in the respiratory diagnostics and treatment.

  4. Neural Conflict–Control Mechanisms Improve Memory for Target Stimuli

    Science.gov (United States)

    Krebs, Ruth M.; Boehler, Carsten N.; De Belder, Maya; Egner, Tobias

    2015-01-01

    According to conflict-monitoring models, conflict serves as an internal signal for reinforcing top-down attention to task-relevant information. While evidence based on measures of ongoing task performance supports this idea, implications for long-term consequences, that is, memory, have not been tested yet. Here, we evaluated the prediction that conflict-triggered attentional enhancement of target-stimulus processing should be associated with superior subsequent memory for those stimuli. By combining functional magnetic resonance imaging (fMRI) with a novel variant of a face-word Stroop task that employed trial-unique face stimuli as targets, we were able to assess subsequent (incidental) memory for target faces as a function of whether a given face had previously been accompanied by congruent, neutral, or incongruent (conflicting) distracters. In line with our predictions, incongruent distracters not only induced behavioral conflict, but also gave rise to enhanced memory for target faces. Moreover, conflict-triggered neural activity in prefrontal and parietal regions was predictive of subsequent retrieval success, and displayed conflict-enhanced functional coupling with medial-temporal lobe regions. These data provide support for the proposal that conflict evokes enhanced top-down attention to task-relevant stimuli, thereby promoting their encoding into long-term memory. Our findings thus delineate the neural mechanisms of a novel link between cognitive control and memory. PMID:24108799

  5. Mechanism of remote controlled after-loading radiotherapy unit

    International Nuclear Information System (INIS)

    Morimoto, Masaki

    1980-01-01

    Employing a small amount of Radium-226 or Cesium-137 source was to be used hitherto for the treatment of carcinoma of the uterine cervix in used After-loading techniques. It involved, however, radiation risk to the staff and patient. The long treatment time are also a pain (strain) on the patient. In recent years, we have developed a remote control after-loading unit, which was named as RALSTRON, which was complete eliminated the disadvantage of conventional radium therapy. This unit also has disadvantage, however, that the design for the remote after-loader for intracavitary applicators present considerable difficulties, because many sources of different active lengths and loading patterns are required. A solution to this problem was carried out by using small point source, placed in Tandem applicator, of high activity and moving them back slowly during the treatment. Recently, this unit was installed many hospitals about 80 units in Japan, and are used. In this paper are given about a mechanism and safety deviced of this unit. (author)

  6. Weathering controls on mechanisms of carbon storage in grassland soils

    Science.gov (United States)

    Masiello, C.A.; Chadwick, O.A.; Southon, J.; Torn, M.S.; Harden, J.W.

    2004-01-01

    On a sequence of soils developed under similar vegetation, temperature, and precipitation conditions, but with variations in mineralogical properties, we use organic carbon and 14C inventories to examine mineral protection of soil organic carbon. In these soils, 14C data indicate that the creation of slow-cycling carbon can be modeled as occurring through reaction of organic ligands with Al3+ and Fe3+ cations in the upper horizons, followed by sorption to amorphous inorganic Al compounds at depth. Only one of these processes, the chelation Al3+ and Fe3+ by organic ligands, is linked to large carbon stocks. Organic ligands stabilized by this process traverse the soil column as dissolved organic carbon (both from surface horizons and root exudates). At our moist grassland site, this chelation and transport process is very strongly correlated with the storage and long-term stabilization of soil organic carbon. Our 14C results show that the mechanisms of organic carbon transport and storage at this site follow a classic model previously believed to only be significant in a single soil order (Spodosols), and closely related to the presence of forests. The presence of this process in the grassland Alfisol, Inceptisol, and Mollisol soils of this chronosequence suggests that this process is a more significant control on organic carbon storage than previously thought. Copyright 2004 by the American Geophysical Union.

  7. Neural conflict-control mechanisms improve memory for target stimuli.

    Science.gov (United States)

    Krebs, Ruth M; Boehler, Carsten N; De Belder, Maya; Egner, Tobias

    2015-03-01

    According to conflict-monitoring models, conflict serves as an internal signal for reinforcing top-down attention to task-relevant information. While evidence based on measures of ongoing task performance supports this idea, implications for long-term consequences, that is, memory, have not been tested yet. Here, we evaluated the prediction that conflict-triggered attentional enhancement of target-stimulus processing should be associated with superior subsequent memory for those stimuli. By combining functional magnetic resonance imaging (fMRI) with a novel variant of a face-word Stroop task that employed trial-unique face stimuli as targets, we were able to assess subsequent (incidental) memory for target faces as a function of whether a given face had previously been accompanied by congruent, neutral, or incongruent (conflicting) distracters. In line with our predictions, incongruent distracters not only induced behavioral conflict, but also gave rise to enhanced memory for target faces. Moreover, conflict-triggered neural activity in prefrontal and parietal regions was predictive of subsequent retrieval success, and displayed conflict-enhanced functional coupling with medial-temporal lobe regions. These data provide support for the proposal that conflict evokes enhanced top-down attention to task-relevant stimuli, thereby promoting their encoding into long-term memory. Our findings thus delineate the neural mechanisms of a novel link between cognitive control and memory. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  8. Multimaterial Control of Instability in Soft Mechanical Metamaterials

    Science.gov (United States)

    Janbaz, Shahram; McGuinness, Molly; Zadpoor, Amir A.

    2018-06-01

    Soft mechanical metamaterials working on the basis of instability have numerous potential applications in the context of "machine materials." Controlling the onset of instability is usually required when rationally designing such metamaterials. We study the isolated and modulated effects of geometrical design and material distribution on the onset of instability in multimaterial cellular metamaterials. We use multimaterial additive manufacturing to fabricate cellular specimens whose unit cells are divided into void space, a square element, and an intermediate ligament. The ratio of the elastic modulus of the ligament to that of the square element [(EL)/(ES)] is changed by using different material types. Computational models are also developed, validated against experimental observations, and used to study a wide range of possible designs. The critical stress can be adjusted independently from the critical strain by changing the material type while keeping [(EL)/(ES)] constant. The critical strain shows a power-law relationship with [(EL)/(ES)] within the range [(EL)/(ES)]=0.1 - 10 . The void shape design alters the critical strain by up to threefold, while the combined effects of the void shape and material distribution cause up to a ninefold change in the critical strain. Our findings highlight the strong influence of material distribution on the onset of the instability and buckling mode.

  9. The imperative for controlled mechanical stresses in unraveling cellular mechanisms of mechanotransduction

    Directory of Open Access Journals (Sweden)

    Sorkin Adam M

    2006-05-01

    Full Text Available Abstract Background In vitro mechanotransduction studies are designed to elucidate cell behavior in response to a well-defined mechanical signal that is imparted to cultured cells, e.g. through fluid flow. Typically, flow rates are calculated based on a parallel plate flow assumption, to achieve a targeted cellular shear stress. This study evaluates the performance of specific flow/perfusion chambers in imparting the targeted stress at the cellular level. Methods To evaluate how well actual flow chambers meet their target stresses (set for 1 and 10 dyn/cm2 for this study at a cellular level, computational models were developed to calculate flow velocity components and imparted shear stresses for a given pressure gradient. Computational predictions were validated with micro-particle image velocimetry (μPIV experiments. Results Based on these computational and experimental studies, as few as 66% of cells seeded along the midplane of commonly implemented flow/perfusion chambers are subjected to stresses within ±10% of the target stress. In addition, flow velocities and shear stresses imparted through fluid drag vary as a function of location within each chamber. Hence, not only a limited number of cells are exposed to target stress levels within each chamber, but also neighboring cells may experience different flow regimes. Finally, flow regimes are highly dependent on flow chamber geometry, resulting in significant variation in magnitudes and spatial distributions of stress between chambers. Conclusion The results of this study challenge the basic premise of in vitro mechanotransduction studies, i.e. that a controlled flow regime is applied to impart a defined mechanical stimulus to cells. These results also underscore the fact that data from studies in which different chambers are utilized can not be compared, even if the target stress regimes are comparable.

  10. Mechanical Engineering Design Project report: Enabler control systems

    Science.gov (United States)

    Cullen, Christian; Delvecchio, Dave; Scarborough, Alan; Havics, Andrew A.

    1992-01-01

    The Controls Group was assigned the responsibility for designing the Enabler's control system. The requirement for the design was that the control system must provide a simple user interface to control the boom articulation joints, chassis articulation joints, and the wheel drive. The system required controlling hydraulic motors on the Enabler by implementing 8-bit microprocessor boards. In addition, feedback to evaluate positions and velocities must be interfaced to provide the operator with confirmation as well as control.

  11. Control rod driving mechanism of reactor, control device and operation method therefor

    International Nuclear Information System (INIS)

    Ariyoshi, Masahiko; Matsumoto, Fujio; Matsumoto, Koji; Kinugasa, Kunihiko; Nara, Yoshihiko; Otama, Kiyomaro; Mikami, Takao

    1998-01-01

    The present invention provides a device for and a method of directly driving control rods of an FBR type reactor linearly by a cylinder type linear motor while having a driving shaft as an electric conductor. Namely, a linear induction motor drives a driving shaft connected with a control rod and vertically moving the control rod by electromagnetic force as an electric conductor. The position of the control rod is detected by a position detector. The driving shaft is hung by a wire by way of an electromagnet which is attachably/detachably held. With such a constitution, the driving shaft connected with the control rod can be vertically moved linearly, stopped or kept. Since they can be driven smoothly at a wide range speed, the responsibility and reliability of the reactor operation can be improved. In addition, since responsibility of the control rod operation is high, scram can be conducted by the linear motor. Since the driving mechanism can be simplified, maintenance and inspection operation can be mitigated. (I.S.)

  12. Control mechanisms in the third-generation planning. Case study: Control to realize sustainable cities

    Science.gov (United States)

    Wicaksono, A. D.

    2017-06-01

    Since the last few years, Indonesia has experienced important events that bring significant changes to the social, political and economic life. The changes directly or indirectly impact the field of planning. With the challenging condition which grows fast and is more complex ahead, and the greater demands on the role of planning, it is required that planning should have higher quality. This paper seeks to answer some questions as follows: (i) How are changes in paradigm and also the development of planning model for the current transition era?, (ii) What is the best way to improve the quality of planning control on the last generation planning model to realize sustainable city?. Analysis steps that will be used to achieve the paper objectives are: (i) Review of planning and sustainable cities theory, (ii) Pattern recognition, (iii) Identifying control mechanisms and sustainable urban forms, (iv) conceptualization. Based on discussion about sustainable cities and control mechanism, some conclusions can be generated as follows: (i) The third generation planning model is based on the theory of expanded system, emphasizing on the constraint of capacity and the ability of planners within the context of larger environment, (ii) There are various theoretical studies that recommend prescriptive model or solution for sustainable urban form and structure. The concepts of Sustainable Cities can be grouped in Neotraditional Development, Urban Containment, Compact City and The Eco-City. The four models above have criteria, namely (i) high density; (ii) a high level of diversity; (iii) mixed land use; (iv) compactness; (5) sustainable transport; (6) passive solar design; (7) Greening Ecological Design. The three main activities in control mechanisms are: Monitoring and Recommendation; a comparative review of the facts (conditions that exist or are developing) with the purpose (expected conditions, set out in urban planning) and recommendations; Evaluation, a review on the

  13. NDE Assessment of PWSCC in Control Rod Drive Mechanism Housings

    International Nuclear Information System (INIS)

    Doctor, Steven R.; Cumblidge, Stephen E.; Schuster, George J.; Harris, Rob V.; Crawford, Susan L.

    2006-01-01

    Studies being conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington are focused on assessing the effectiveness of Nondestructive examination (NDE) techniques for inspecting control rod drive mechanism (CRDM) nozzles and J-groove weldments. The primary objective of this work is to provide information to the United States Nuclear Regulatory Commission (US NRC) on the effectiveness of NDE methods as related to the in-service inspection of CRDM nozzles and J-groove weldments, and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. In describing two CRDM assemblies removed from service, decontaminated, and then used in a series of NDE measurements, this paper will address the following questions: (1) What did each technique detect?, (2) What did each technique miss?, (3) How accurately did each technique characterize the detected flaws? Two CRDM assemblies including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material were selected for this study. One contained suspected PWSCC, based on in-service inspection data and through-wall leakage; the other contained evidence suggesting through-wall leakage, but this was unconfirmed. The selected NDE measurements follow standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. In addition, laboratory based NDE methods were employed to conduct inspections of the CRDM assemblies, with particular emphasis on inspecting the J-groove weld and buttering. This paper will also describe the NDE methods used and discuss the NDE results. Future work will involve using the results from these NDE studies to guide the development of a destructive characterization plan to reveal the crack morphology and a comparison of the degradation found by the destructive evaluation with the recorded NDE responses.

  14. Control of forced vibrations of mechanical structures by an electromagnetic controller with a permanent magnet

    DEFF Research Database (Denmark)

    Stein, George Juraj; Darula, Radoslav; Sorokin, Sergey

    2012-01-01

    A theoretical analysis of an electromagnetic vibration controller is presented. The analyzed device consists of a pot-type iron core with a coil and a permanent magnet as a source of constant magnetic flux. The magnetic circuit is closed by a yoke, excited by an external harmonic mechanical force....... The so generated magnetic flux variation induces alternating voltage in the electric circuit, which is dissipated in a shunt resistor. The induced current driven through the coil generates magnetic force, which damps the excitation force and changes the damped natural frequency of the oscillatory system....... Due to the hysteretic effects in the magnetic material the internal losses influence the overall system’s performance. A mathematical model of the force balance in the oscillatory system is derived in a simplified, linearised form. The electric as well as mechanical system is modelled using lumped...

  15. Photophysics of GaN single-photon emitters in the visible spectral range

    Science.gov (United States)

    Berhane, Amanuel M.; Jeong, Kwang-Yong; Bradac, Carlo; Walsh, Michael; Englund, Dirk; Toth, Milos; Aharonovich, Igor

    2018-04-01

    In this work, we present a detailed photophysical analysis of recently discovered, optically stable single-photon emitters (SPEs) in gallium nitride (GaN). Temperature-resolved photoluminescence measurements reveal that the emission lines at 4 K are three orders of magnitude broader than the transform-limited width expected from excited-state lifetime measurements. The broadening is ascribed to ultrafast spectral diffusion. The photophysical study on several emitters at room temperature (RT) reveals an average brightness of (427 ±215 )kCounts /s . Finally, polarization measurements from 14 emitters are used to determine visibility as well as dipole orientation of defect systems within the GaN crystal. Our results underpin some of the fundamental properties of SPEs in GaN both at cryogenic and RT, and define the benchmark for future work in GaN-based single-photon technologies.

  16. Spectroscopy and photophysics of flavin related compounds: Riboflavin and iso-(6,7)-riboflavin

    International Nuclear Information System (INIS)

    Sikorska, Ewa; Khmelinskii, Igor; Komasa, Anna; Koput, Jacek; Ferreira, Luis F.V.; Herance, Jose R.; Bourdelande, Jose L.; Williams, Sian L.; Worrall, David R.; Insinska-Rak, MaIgorzata; Sikorski, Marek

    2005-01-01

    The photochemistry and photophysics of isoalloxazines (10-substituted 2,3,4,10-tetrahydro-benzo[g]pteridine-2,4-diones), and especially flavins (7,8-dimethyl substituted isoalloxazines), are of considerable interest due to the biological relevance of these compounds. In this paper we report data concerning the photophysics of riboflavin and iso-(6,7)-riboflavin (10-(2,3,4,5-tetrahydroxypentyl)-6,7-dimethylbenzo[g]pteridine-2,4(3H,10H) -dione), and correlate the spectroscopic observations with theoretical calculations performed using time-dependent density functional theory. On the basis of these calculations the lowest excited singlet and triplet states are both assigned (π,π*) symmetry, and this result is used to explain the relatively low singlet oxygen quantum yields in comparison with alloxazines. Time-resolved emission studies have indicated 6,7-dimethylalloxazine a photodegradation product of iso-(6,7)-riboflavin

  17. Photophysical, Photochemical, and BQ Quenching Properties of Zinc Phthalocyanines with Fused or Interrupted Extended Conjugation

    Directory of Open Access Journals (Sweden)

    Gülşah Gümrükçü

    2014-01-01

    Full Text Available The effects of substituents and solvents on the photophysical and photochemical parameters of zinc(II phthalocyanines containing four Schiff’s base substituents attached directly and through phenyleneoxy-bridges on peripheral positions are reported. The group effects on peripheral position and the continual and intermittent conjugation of the phthalocyanine molecules on the photophysical and photochemical properties are also investigated. General trends are described for photodegradation, singlet oxygen, and fluorescence quantum yields of these compounds in dimethylsulfoxide (DMSO, dimethylformamide (DMF, and tetrahydrofurane (THF. Among the different substituents, phthalocyanines with cinnamaldimine moieties (1c and 2c have the highest singlet oxygen quantum yields (ΦΔ and those with nitro groups (1a and 2a have the highest fluorescence quantum yields in all the solvents used. The fluorescence of the substituted zinc(II phthalocyanine complexes is effectively quenched by 1,4-benzoquinone (BQ in these solvents.

  18. Matlab/simMechanics based control of four-bar passive lower-body mechanism for rehabilitation

    Directory of Open Access Journals (Sweden)

    Ashish Singla

    2016-09-01

    Full Text Available In recent times, use of wearable devices is becoming popular for providing precise ways of rehabilitation. The focus of this paper is to propose a passive lower body mechanism using a four-bar linkage, which can be actuated via the hip joint to move the other two joints at knee and ankle as well. Simulations are performed here by considering an average male human (height six feet by modelling the gait cycle in CAD software and executing the control strategy in the SimMechanics, which provides a convenient way to study without use of detailed computational mathematics. The study of the controller aspects of the passive mechanism is presented with both PD and PID controllers with auto- and manual-tuned gains. Significant reduction in actuator torques is observed with the manually-tuned PID controller over automatically-tuned PID controller with marginal degradation in the overshoot and settling time.

  19. Modular overconstrained weak-link mechanism for ultraprecision motion control

    International Nuclear Information System (INIS)

    Shu Deming; Toellner, Thomas S.; Alp, Esen E.

    2001-01-01

    We have designed and constructed a novel miniature overconstrained weak-link mechanism that will allow positioning of two crystals with better than 50 nrad angular resolution and nanometer linear driving sensitivity. The precision and stability of this structure allow the user to align or adjust an assembly of crystals to achieve the same performance as does a single channel-cut crystal, so we call it an ''artificial channel-cut crystal.'' Unlike the traditional kinematic linear spring mechanisms, the overconstrained weak-link mechanism provides much higher structure stiffness and stability. Using a laminar structure configured and manufactured by chemical etching and lithography techniques, we are able to design and build a planar-shape, high stiffness, high precision weak-link mechanism. In this paper, we present recent developments for the overconstrained weak-link mechanism. Applications of this new technique to synchrotron radiation instrumentation are also discussed

  20. Protein-based nanostructures as carriers for photo-physically active molecules in biosystems

    OpenAIRE

    Delcanale, Pietro

    2017-01-01

    In nature, many proteins function as carriers, being able to bind, transport and possibly release a ligand within a biological system. Protein-based carriers are interesting systems for drug delivery, with the remarkable advantage of being water-soluble and, as inherent components of biosystems, highly bio-compatible. This work focuses on the use of protein-based carriers for the delivery of hydrophobic photo-physically active molecules, whose structure and chemical properties lead to spontan...

  1. Working principle and structure characteristics analysis of the reactivity control drive mechanism

    International Nuclear Information System (INIS)

    Zhao Tianyu; Huang Zhiyong; Chen Feng; He Xuedong

    2010-01-01

    The startup, power regulation and safety shutdown of the nuclear reactor are operated by the reactivity control devices. Reactivity control drive mechanism is a key mechanical transmission component, which directly control the location of the neutron absorber in the core. Its working condition is complex, and its service life should be long., which requires high reliability. PWR as well as newly developed different type of reactors have different control devices drive mechanism. This paper mainly do analysis and comparison about the working environment, mechanical transmission principle, structure, performance, service life and other aspects of PWR, HTR control devices drive mechanism. In addition, this paper is also based on the working principles of reactive control devices drive mechanism, also consider the trends of its design and test verification by the international countries, and discussed the method and feasibility of improving and perfecting the structure and function of drive mechanism. (authors)

  2. Synthesis and photophysical properties of a series of cyclopenta[b]naphthalene solvatochromic fluorophores.

    Science.gov (United States)

    Benedetti, Erica; Kocsis, Laura S; Brummond, Kay M

    2012-08-01

    The synthesis and photophysical properties of a series of naphthalene-containing solvatochromic fluorophores are described within. These novel fluorophores are prepared using a microwave-assisted dehydrogenative Diels-Alder reaction of styrene, followed by a palladium-catalyzed cross coupling reaction to install an electron donating amine group. The new fluorophores are structurally related to Prodan. Photophysical properties of the new fluorophores were studied and intriguing solvatochromic behavior was observed. For most of these fluorophores, high quantum yields (60-99%) were observed in methylene chloride in addition to large Stokes shifts (95-226 nm) in this same solvent. As the solvent polarity increased, so did the observed Stokes shift with one derivative displaying a Stokes shift of ~300 nm in ethanol. All fluorophore emission maxima, and nearly all absorption maxima were significantly red-shifted when compared to Prodan. Shifting the absorption and emission maxima of a fluorophore into the visible region increases its utility in biological applications. Moreover, the cyclopentane portion of the fluorophore structure provides an attachment point for biomolecules that will minimize disruptions of the photophysical properties.

  3. Photo-physical and structural interactions between viologen phosphorus-based dendrimers and human serum albumin

    International Nuclear Information System (INIS)

    Ciepluch, Karol; Katir, Nadia; El Kadib, Abdelkrim; Weber, Monika; Caminade, Anne-Marie; Bousmina, Mostapha; Pierre Majoral, Jean; Bryszewska, Maria

    2012-01-01

    This work deals with photo-physical and structural interactions between viologen phosphorus dendrimers and human serum albumin (HSA). Viologens are derivatives of 4,4′-bipyridinium salts. Aiming to rationalize the parameters governing such interactions eight types of these polycationic dendrimers in which the generation, the number of charges, the nature of the core and of the terminal groups vary from one to another, were designed and used. The influence of viologen-based dendrimers' on human serum albumin has been investigated. The photo-physical interactions of the two systems have been monitored by fluorescence quenching of free L-tryptophan and of HSA tryptophan residue. Additionally, using circular dichroism (CD) the effect of dendrimers on the secondary structure of albumin was measured. The obtained results show that viologen dendrimers interact with human serum albumin quenching its fluorescence either by collisional (dynamic) way or by forming complexes in a ground state (static quenching). In some cases the quenching is accompanied by changes of the secondary structure of HSA. - Highlights: ► Photo-physical interactions between viologen phosphorus dendrimers and human serum albumin (HSA) were investigated. ► The viologen dendrimers can quench the fluorescence of tryptophan in HSA. ► CD spectra to explain the changes in secondary structure of albumin after exposition of dendrimers.

  4. Photo-physical and structural interactions between viologen phosphorus-based dendrimers and human serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Ciepluch, Karol, E-mail: ciepluch@biol.uni.lodz.pl [Department of General Biophysics, University of Lodz, 141/143 Pomorska St., 90-236 Lodz (Poland); Katir, Nadia [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 route de Narbonne, F-31077 Toulouse cedex 4 (France); Institute of Nanomaterials and Nanotechnology (INANOTECH)-MAScIR (Moroccan Foundation for Advanced Science, Innovation and Research), ENSET, Avenue de l' Armee Royale, Madinat El Irfane, 10100 Rabat (Morocco); El Kadib, Abdelkrim [Institute of Nanomaterials and Nanotechnology (INANOTECH)-MAScIR (Moroccan Foundation for Advanced Science, Innovation and Research), ENSET, Avenue de l' Armee Royale, Madinat El Irfane, 10100 Rabat (Morocco); Weber, Monika [Department of General Biophysics, University of Lodz, 141/143 Pomorska St., 90-236 Lodz (Poland); Caminade, Anne-Marie [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 route de Narbonne, F-31077 Toulouse cedex 4 (France); Bousmina, Mostapha [Hassan II Academy of Sciences and Technology, Avenue MVI, Km4, 10220 Rabat (Morocco); Pierre Majoral, Jean [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 route de Narbonne, F-31077 Toulouse cedex 4 (France); Hassan II Academy of Sciences and Technology, Avenue MVI, Km4, 10220 Rabat (Morocco); Bryszewska, Maria [Department of General Biophysics, University of Lodz, 141/143 Pomorska St., 90-236 Lodz (Poland)

    2012-06-15

    This work deals with photo-physical and structural interactions between viologen phosphorus dendrimers and human serum albumin (HSA). Viologens are derivatives of 4,4 Prime -bipyridinium salts. Aiming to rationalize the parameters governing such interactions eight types of these polycationic dendrimers in which the generation, the number of charges, the nature of the core and of the terminal groups vary from one to another, were designed and used. The influence of viologen-based dendrimers' on human serum albumin has been investigated. The photo-physical interactions of the two systems have been monitored by fluorescence quenching of free L-tryptophan and of HSA tryptophan residue. Additionally, using circular dichroism (CD) the effect of dendrimers on the secondary structure of albumin was measured. The obtained results show that viologen dendrimers interact with human serum albumin quenching its fluorescence either by collisional (dynamic) way or by forming complexes in a ground state (static quenching). In some cases the quenching is accompanied by changes of the secondary structure of HSA. - Highlights: Black-Right-Pointing-Pointer Photo-physical interactions between viologen phosphorus dendrimers and human serum albumin (HSA) were investigated. Black-Right-Pointing-Pointer The viologen dendrimers can quench the fluorescence of tryptophan in HSA. Black-Right-Pointing-Pointer CD spectra to explain the changes in secondary structure of albumin after exposition of dendrimers.

  5. Photophysical and photochemical properties of novel metallophthalocyanines bearing 7-oxy-3-(m-methoxyphenyl)coumarin groups

    Energy Technology Data Exchange (ETDEWEB)

    Taştemel, Ayşegül; Karaca, Birsen Yılmaz [Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadıkoy-Istanbul (Turkey); Durmuş, Mahmut [Gebze Technical University, Department of Chemistry, P.O. Box 141, Gebze 41400, Kocaeli (Turkey); Bulut, Mustafa, E-mail: mbulut@marmara.edu.tr [Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadıkoy-Istanbul (Turkey)

    2015-12-15

    Tetra-peripherally and non-peripherally 7-oxy-3-(m-methoxyphenyl)coumarin-substituted zinc(II) (4a and 5a), indium(III)acetate (4b and 5b) and magnesium(II) (4c and 5c) phthalocyanines were synthesized for the first time. These phthalocyanines were characterized by elemental analysis, FT-IR, {sup 1}H NMR, UV–vis spectroscopy and mass spectra. The novel phthalocyanines showed excellent solubility in general organic solvents, such as dichloromethane, chloroform, tetrahydrofuran (THF), N,N-dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The photophysical and photochemical properties of these phthalocyanines were investigated in DMF. The effects of the central metal ions (Zn{sup 2+}, Mg{sup 2+}, In{sup +3}) and the position (peripheral or non-peripheral) of the substituents on the photophysical and photochemical parameters were reported for comparison. The singlet oxygen quantum yield values of novel phthalocyanines ranged from 0.29 to 0.82 in DMF. In this study, the fluorescence quenching behavior of the studied zinc(II) and magnesium(II) phthalocyanine complexes was also described by the addition of 1,4-benzoquinone. - Highlights: • 7-oxy-3-(m-methoxyphenyl)coumarin-substituted Zn, In(III)OAc and Mg phthalocyanines. • Investigation of their photophysical and photochemical properties in DMF. • The effects of metal types and position of the substituents on these properties.

  6. Photophysical and photochemical properties of novel metallophthalocyanines bearing 7-oxy-3-(m-methoxyphenyl)coumarin groups

    International Nuclear Information System (INIS)

    Taştemel, Ayşegül; Karaca, Birsen Yılmaz; Durmuş, Mahmut; Bulut, Mustafa

    2015-01-01

    Tetra-peripherally and non-peripherally 7-oxy-3-(m-methoxyphenyl)coumarin-substituted zinc(II) (4a and 5a), indium(III)acetate (4b and 5b) and magnesium(II) (4c and 5c) phthalocyanines were synthesized for the first time. These phthalocyanines were characterized by elemental analysis, FT-IR, 1 H NMR, UV–vis spectroscopy and mass spectra. The novel phthalocyanines showed excellent solubility in general organic solvents, such as dichloromethane, chloroform, tetrahydrofuran (THF), N,N-dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The photophysical and photochemical properties of these phthalocyanines were investigated in DMF. The effects of the central metal ions (Zn 2+ , Mg 2+ , In +3 ) and the position (peripheral or non-peripheral) of the substituents on the photophysical and photochemical parameters were reported for comparison. The singlet oxygen quantum yield values of novel phthalocyanines ranged from 0.29 to 0.82 in DMF. In this study, the fluorescence quenching behavior of the studied zinc(II) and magnesium(II) phthalocyanine complexes was also described by the addition of 1,4-benzoquinone. - Highlights: • 7-oxy-3-(m-methoxyphenyl)coumarin-substituted Zn, In(III)OAc and Mg phthalocyanines. • Investigation of their photophysical and photochemical properties in DMF. • The effects of metal types and position of the substituents on these properties.

  7. Photo-physics of third-order nonlinear optical processes in organic dyes

    International Nuclear Information System (INIS)

    Delysse, Stephane

    1997-01-01

    We study some aspects of the nonlinear picosecond photo-physics in organic dyes using Kerr ellipsometry. The aim is to establish link between the photo-physics and nonlinear optics in these compounds. First, we study coherent processes directly linked to the third-order susceptibility. Thus, we measure two-photon absorption spectra of large internal charge transfer dyes. We take into account all coupling between three electronic states which can interfere to explain the particular response of some stilbene dyes. On the second hand, we expose a more photophysical approach to determine the S 1 → S n transition energies and moments using the measurement of excited state absorption cross sections. These results allow the prediction of the susceptibilities relevant to alternative nonlinear optical methods. Nevertheless, the stationary approach hides the complex relaxation processes which can take place in organic dyes. As an illustration, we study the formation and disappearance of a TICT (Twisted intramolecular charge transfer) in a pyrylium salt in solvents of increasing viscosity. (author) [fr

  8. Calculus of variations mechanics, control and other applications

    CERN Document Server

    MacCluer, Charles R

    2012-01-01

    First truly up-to-date treatment offers a simple introduction to optimal control, linear-quadratic control design, and more. Broad perspective features numerous exercises, hints, outlines, and appendixes, including a practical discussion of MATLAB. 2005 edition.

  9. Smooth controllability of infinite-dimensional quantum-mechanical systems

    International Nuclear Information System (INIS)

    Wu, Re-Bing; Tarn, Tzyh-Jong; Li, Chun-Wen

    2006-01-01

    Manipulation of infinite-dimensional quantum systems is important to controlling complex quantum dynamics with many practical physical and chemical backgrounds. In this paper, a general investigation is casted to the controllability problem of quantum systems evolving on infinite-dimensional manifolds. Recognizing that such problems are related with infinite-dimensional controllability algebras, we introduce an algebraic mathematical framework to describe quantum control systems possessing such controllability algebras. Then we present the concept of smooth controllability on infinite-dimensional manifolds, and draw the main result on approximate strong smooth controllability. This is a nontrivial extension of the existing controllability results based on the analysis over finite-dimensional vector spaces to analysis over infinite-dimensional manifolds. It also opens up many interesting problems for future studies

  10. Error-controlled adaptive finite elements in solid mechanics

    National Research Council Canada - National Science Library

    Stein, Erwin; Ramm, E

    2003-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Error-controlled Adaptive Finite-element-methods . . . . . . . . . . . . Missing Features and Properties of Today's General Purpose FE Programs for Structural...

  11. Control of a perturbed under-actuated mechanical system

    KAUST Repository

    Zayane, Chadia; Laleg-Kirati, Taous-Meriem; Chemori, Ahmed

    2015-01-01

    In this work, the trajectory tracking problem for an under-actuated mechanical system in presence of unknown input disturbances is addressed. The studied inertia wheel inverted pendulum falls in the class of non minimum phase systems. The proposed

  12. Neuronal Mechanisms and Bloodflow Control of Infrared Reception in Snakes

    National Research Council Canada - National Science Library

    Goris, Richard

    2004-01-01

    The infrared pit organs of pit vipers and pythons were studied with emphasis on bloodflow in the capillary bed and its possible role as a cooling mechanism for the pit receptors stimulated by infrared (= heat...

  13. Development of an Outdoor Temperature-Based Control Algorithm for Residential Mechanical Ventilation Control

    Energy Technology Data Exchange (ETDEWEB)

    Less, Brennan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tang, Yihuan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-06-01

    Smart ventilation systems use controls to ventilate more during those periods that provide either an energy or IAQ advantage (or both) and less during periods that provide a dis advantage. Using detailed building simulations, this study addresses one of the simplest and lowest cost types of smart controllers —outdoor temperature- based control. If the outdoor temperature falls below a certain cut- off, the fan is simply turned off. T he main principle of smart ventilation used in this study is to shift ventilation from time periods with large indoor -outdoor temperature differences, to periods where these differences are smaller, and their energy impacts are expected to be less. Energy and IAQ performance are assessed relative to a base case of a continuously operated ventilation fan sized to comply with ASHRAE 62.2-2013 whole house ventilation requirements. In order to satisfy 62.2-2013, annual pollutant exposure must be equivalent between the temperature controlled and continuous fan cases. This requires ventilation to be greater than 62.2 requirements when the ventilation system operates. This is achieved by increasing the mechanical ventilation system air flow rates.

  14. A dual flow bioreactor with controlled mechanical stimulation for cartilage tissue engineering

    NARCIS (Netherlands)

    Spitters, Tim; Leijten, Jeroen Christianus Hermanus; Deus, F.D.; Costa, I.B.F.; van Apeldoorn, Aart A.; van Blitterswijk, Clemens; Karperien, Hermanus Bernardus Johannes

    2013-01-01

    In cartilage tissue engineering bioreactors can create a controlled environment to study chondrocyte behavior under mechanical stimulation or produce chondrogenic grafts of clinically relevant size. Here we present a novel bioreactor, which combines mechanical stimulation with a two compartment

  15. The Parent Control in the Mechanical Engineering Management-Holding

    Science.gov (United States)

    Šnircová, Jana; Hodulíková, Petra; Joehnk, Peter

    2012-12-01

    The group of entities under the control of parent, so called holding, is arisen as the result and the most often used form of the business concentration nowadays. The paper is focused to find special tasks of parent company for to preserve effective unified economic control in the management-holding. The unified economic control the holding exists in the conditions of the main conflict of interest - holding is not a legal but economic unit and the connected companies into it have a legal autonomy with the economic dependence. The unified economic control limits the financial independence of every individual company of the holding. The attention in the paper is concentrated to the management concept of the parent control, i.e. the parent company supervises the control of intragroup flows and all of subsidiaries production activities.

  16. Study on photophysical and aggregation induced emission recognition of 1,8-naphthalimide probe for casein by spectroscopic method

    Science.gov (United States)

    Sun, Yang; Liu, Zhen; Liang, Xuhua; Fan, Jun; Han, Quan

    2013-05-01

    A novel water-soluble 1,8-naphthalimide derivative 1, bearing two acetic carboxylic groups, exhibited fluorescent turn-on recognition for casein based on the aggregation induced emission (AIE) character. The photophysical properties of 1 consisting of donor and acceptor units were investigated in different solutions. The fluorescence intensity decreased through taking advantage of twisted intramolecular charge transfer (TICT) and self-association emission with increasing solvent polarity. Moreover, the spectral red-shift and intensity quench in protic solvents were caused by the excited-state hydrogen bond strengthening effect. Density Functional Theory (DFT) calculations revealed that 1 exhibited a strong TICT character. The AIE mechanism of 1 with casein was due to 1 docked in the hydrophobic cavity between sub-micelles and bound with Tyr and Trp residues, resulting in the aggregation of 1 on the casein surface and emission enhancement. Based on this, a novel casein assay method was developed. The proposed exhibited a good linear range from 0.1 to 22 μg mL-1, with the detection limit of 2.8 ng mL-1. Satisfactory reproducibility, reversibility and a short response time were realized. This method was applied to the determination of casein in milk powder samples and the results were in good agreement with the result of Biuret method.

  17. Dependence of Exciton Diffusion Length and Diffusion Coefficient on Photophysical Parameters in Bulk Heterojunction Organic Solar Cells

    Science.gov (United States)

    Yeboah, Douglas; Singh, Jai

    2017-11-01

    Recently, the dependence of exciton diffusion length (LD ) on some photophysical parameters of organic solids has been experimentally demonstrated, however no systematic theoretical analysis of this phenomenon has been carried out. We have conducted a theoretical study by using the Förster resonance energy transfer and Dexter carrier transfer mechanisms together with the Einstein-Smoluchowski diffusion equation to derive analytical models for the diffusion lengths (LD ) and diffusion coefficients (D) of singlet (S) and triplet (T) excitons in organic solids as functions of spectral overlap integral (J) , photoluminescence (PL) quantum yield (φD ) , dipole moment (μT ) and refractive index (n) of the photoactive material. The exciton diffusion lengths and diffusion coefficients in some selected organic solids were calculated, and we found that the singlet exciton diffusion length (LDS ) increases with φD and J, and decreases with n. Also, the triplet exciton diffusion length (LDT ) increases with φD and decreases with μT . These may be achieved through doping the organic solids into broad optical energy gap host materials as observed in previous experiments. The calculated exciton diffusion lengths are compared with experimental values and a reasonably good agreement is found between them. The results presented are expected to provide insight relevant to the synthesis of new organic solids for fabrication of bulk heterojunction organic solar cells characterized by better power conversion efficiency.

  18. Photophysical studies of zinc phthalocyanine and chloroaluminum phthalocyanine incorporated into liposomes in the presence of additives

    Directory of Open Access Journals (Sweden)

    S.M.T. Nunes

    2004-02-01

    Full Text Available The photophysical properties of zinc phthalocyanine (ZnPC and chloroaluminum phthalocyanine (AlPHCl incorporated into liposomes of dimyristoyl phosphatidylcholine in the presence and absence of additives such as cholesterol or cardiolipin were studied by time-resolved fluorescence, laser flash photolysis and steady-state techniques. The absorbance of the drugs changed linearly with drug concentration, at least up to 5.0 µM in homogeneous and heterogeneous media, indicating that aggregation did not occur in these media within this concentration range. The incorporation of the drugs into liposomes increases the dimerization constant by one order of magnitude (for ZnPC, 3.6 x 10(4 to 1.0 x 10(5 M-1 and for AlPHCl, 3.7 x 10(4 to 1.5 x 10(5 M-1, but this feature dose does not rule out the use of this carrier, since the incorporation of these hydrophobic drugs into liposomes permits their systemic administration. Probe location in biological membranes and predominant positions of the phthalocyanines in liposomes were inferred on the basis of their fluorescence and triplet state properties. Both phthalocyanines are preferentially distributed in the internal regions of the liposome bilayer. The additives affect the distribution of these drugs within the liposomes, a fact that controls their delivery when both are used in a biological medium, retarding their release. The addition of the additives to the liposomes increases the internalization of phthalocyanines. The interaction of the drugs with a plasma protein, bovine serum albumin, was examined quantitatively by the fluorescence technique. The results show that when the drugs were incorporated into small unilamellar liposomes, the association with albumin was enhanced when compared with organic media, a fact that should increase the selectivity of tumor targeting by these phthalocyanines (for ZnPC, 0.71 x 10(6 to 1.30 x 10(7 M-1 and for AlPHCl, 4.86 x 10(7 to 3.10 x 10(8 M-1.

  19. Mechanisms of Molecular Response in the Optimal Control of Photoisomerization

    International Nuclear Information System (INIS)

    Dietzek, Benjamin; Brueggemann, Ben; Pascher, Torbjoern; Yartsev, Arkady

    2006-01-01

    We report on adaptive feedback control of photoinduced barrierless isomerization of 1,1'-diethyl-2,2'-cyanine in solution. We compare the effect of different fitness parameters and show that optimal control of the absolute yield of isomerization (photoisomer concentration versus excitation photons) can be achieved, while the relative isomerization yield (photoisomer concentration versus number of relaxed excited-state molecules) is unaffected by adaptive feedback control. The temporal structure of the optimized excitation pulses allows one to draw clear mechanistic conclusions showing the critical importance of coherent nuclear motion for the control of isomerization

  20. Mechanisms Involved in Nematode Control by Endophytic Fungi.

    Science.gov (United States)

    Schouten, Alexander

    2016-08-04

    Colonization of plants by particular endophytic fungi can provide plants with improved defenses toward nematodes. Evidently, such endophytes can be important in developing more sustainable agricultural practices. The mechanisms playing a role in this quantitative antagonism are poorly understood but most likely multifactorial. This knowledge gap obstructs the progress regarding the development of endophytes or endophyte-derived constituents into biocontrol agents. In part, this may be caused by the fact that endophytic fungi form a rather heterogeneous group. By combining the knowledge of the currently characterized antagonistic endophytic fungi and their effects on nematode behavior and biology with the knowledge of microbial competition and induced plant defenses, the various mechanisms by which this nematode antagonism operates or may operate are discussed. Now that new technologies are becoming available and more accessible, the currently unresolved mechanisms can be studied in greater detail than ever before.

  1. Neural networks for predictive control of the mechanism of ...

    African Journals Online (AJOL)

    In this paper, we are interested in the study of the control of orientation of a wind turbine like means of optimization of his output/input ratio (efficiency). The approach suggested is based on the neural predictive control which is justified by the randomness of the wind on the one hand, and on the other hand by the capacity of ...

  2. A predictive control scheme for automated demand response mechanisms

    NARCIS (Netherlands)

    Lampropoulos, I.; Bosch, van den P.P.J.; Kling, W.L.

    2012-01-01

    The development of demand response mechanisms can provide a considerable option for the integration of renewable energy sources and the establishment of efficient generation and delivery of electrical power. The full potential of demand response can be significant, but its exploration still remains

  3. Adaptive repetitive control of a compact disc mechanism

    NARCIS (Netherlands)

    Dötsch, H.G.M.; Smakman, H.T.; Hof, Van den P.M.J.; Steinbuch, M.

    1995-01-01

    Radial track following of a compact disc player servo mechanism is severely exposed to periodic disturbances, induced by the eccentric rotation of the disc. The period of this disturbance is not available for measurement and varies slowly in time. Periodic disturbances can be adequately attenuated

  4. CONCEPTUAL APPROACHES TO CREATE CONTROL MECHANISM BY PASSENGER COMMUTATION SERVICES

    Directory of Open Access Journals (Sweden)

    V. O. Zadoya

    2010-11-01

    Full Text Available In the article the basic approaches of improving a management mechanism for passenger suburban railway transportations are considered, and the classification of reformation models for passenger suburban railway transportations depending on scales, degree of independence, department subordination and amount of proprietors of future company is offered.

  5. Mechanisms Involved in Nematode Control by Endophytic Fungi

    NARCIS (Netherlands)

    Schouten, Sander

    2016-01-01

    Colonization of plants by particular endophytic fungi can provide plants with improved defenses toward nematodes. Evidently, such endophytes can be important in developing more sustainable agricultural practices. The mechanisms playing a role in this quantitative antagonism are poorly understood

  6. Control of distributed heat transfer mechanisms in membrane distillation plants

    KAUST Repository

    Laleg-Kirati, Taous-Meriem; Eleiwi, Fadi; Karam, Ayman M.

    2017-01-01

    Various examples are provided that are related to boundary control in membrane distillation (MD) processes. In one example, a system includes a membrane distillation (MD) process comprising a feed side and a permeate side separated by a membrane

  7. Robust tracking control for linear vibrating mechanical systems

    Directory of Open Access Journals (Sweden)

    Francisco Beltrán-Carbajal

    2015-01-01

    Full Text Available Se propone un enfoque de control novedoso para seguimiento por realimentación de la salida para sistemas mecánicos vibratorios del tipo masa-resorte-amortiguador lineales sub-actuados. La metodología de diseño de control que se presenta considera robustez con respecto de dinámicas no modeladas y fuerzas externas. El esquema de control propuesto solamente requiere mediciones de la variable de la salida de posición. Se utiliza compensación integral del error de seguimiento de manera apropiada para evitar la estimación en tiempo real de las perturbaciones. Resultado analíticos y numéricos muestran la efectividad del esquema de control activo de vibración para atenuación de vibraciones resonantes y caóticas afectando la respuesta de la variable de salida.

  8. Quantum and classical control of single photon states via a mechanical resonator

    International Nuclear Information System (INIS)

    Basiri-Esfahani, Sahar; Myers, Casey R; Combes, Joshua; Milburn, G J

    2016-01-01

    Optomechanical systems typically use light to control the quantum state of a mechanical resonator. In this paper, we propose a scheme for controlling the quantum state of light using the mechanical degree of freedom as a controlled beam splitter. Preparing the mechanical resonator in non-classical states enables an optomechanical Stern–Gerlach interferometer. When the mechanical resonator has a small coherent amplitude it acts as a quantum control, entangling the optical and mechanical degrees of freedom. As the coherent amplitude of the resonator increases, we recover single photon and two-photon interference via a classically controlled beam splitter. The visibility of the two-photon interference is particularly sensitive to coherent excitations in the mechanical resonator and this could form the basis of an optically transduced weak-force sensor. (paper)

  9. Disentangling the Impact of Control-Enhancing Mechanisms on Firm Performance

    DEFF Research Database (Denmark)

    Zattoni, Alessandro; Pedersen, Torben

    2011-01-01

    shareholders to expropriate minority shareholders. The aim of this article is to contribute to the current debate investigating the implications of these control-enhancing mechanisms on firm performance. To reach this purpose, we collected ownership data on the (100) largest listed companies per capitalization......Governance scholars and investors traditionally advocate against the use of control enhancing mechanisms, i.e. mechanisms aimed at separating voting and cash flow rights. These mechanisms may, in fact, determine a deviation from the proportionality principle and may encourage large and controlling...... in five European countries (i.e. France, Germany, Italy, Spain, and the UK). Then we tested the consequences of control-enhancing mechanisms for firm performance using 2SLS regression models. Our results show that (i) mechanisms that lock-in control do have a direct and negative impact on firm performance...

  10. Automatic control of arterial carbon dioxide tension in mechanically ventilated patients.

    Science.gov (United States)

    Fernando, Tyrone; Cade, John; Packer, John

    2002-12-01

    This paper presents a method of controlling the arterial carbon dioxide tension of patients receiving mechanical ventilation. Controlling of the CO2 tension is achieved by regulating the ventilator initiated breath frequency and also volume per breath.

  11. The Application of LOGO! in Control System of a Transmission and Sorting Mechanism

    Science.gov (United States)

    Liu, Jian; Lv, Yuan-Jun

    Logic programming of general logic control module LOGO! has been recommended the application in transmission and sorting mechanism. First, the structure and operating principle of the mechanism had been introduced. Then the pneumatic loop of the mechanism had been plotted in the software of FluidSIM-P. At last, pneumatic loop and motors had been control by LOGO!, which makes the control process simple and clear instead of the complicated control of ordinary relay. LOGO! can achieve the complicated interlock control composed of inter relays and time relays. In the control process, the logic control function of LOGO! is fully used to logic programming so that the system realizes the control of air cylinder and motor. It is reliable and adjustable mechanism after application.

  12. Mechanical control over valley magnetotransport in strained graphene

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ning, E-mail: maning@stu.xjtu.edu.cn [Department of Physics, MOE Key Laboratory of Advanced Transducers and Intelligent Control System, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Shengli, E-mail: zhangsl@mail.xjtu.edu.cn [Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Daqing, E-mail: liudq@cczu.edu.cn [School of Mathematics and Physics, Changzhou University, Changzhou 213164 (China)

    2016-05-06

    Recent experiments report that the graphene exhibits Landau levels (LLs) that form in the presence of a uniform strain pseudomagnetic field with magnitudes up to hundreds of tesla. We further reveal that the strain removes the valley degeneracy in LLs, and leads to a significant valley polarization with inversion symmetry broken. This accordingly gives rise to the well separated valley Hall plateaus and Shubnikov–de Haas oscillations. These effects are absent in strainless graphene, and can be used to generate and detect valley polarization by mechanical means, forming the basis for the new paradigm “valleytronics” applications. - Highlights: • We explore the mechanical strain effects on the valley magnetotransport in graphene. • We analytically derive the dc collisional and Hall conductivities under strain. • The strain removes the valley degeneracy in Landau levels. • The strain causes a significant valley polarization with inversion symmetry broken. • The strain leads to the well separated valley Hall and Shubnikov–de Haas effects.

  13. Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids

    International Nuclear Information System (INIS)

    Woods, L.L.; Mizelle, H.L.; Montani, J.P.; Hall, J.E.

    1986-01-01

    Our purpose was to investigate the mechanisms by which increased plasma amino acids elevate renal blood flow (RBF) and glomerular filtration rate (GFR). Since transport of amino acids and Na + is linked in the proximal tubule, the authors hypothesized that increased amino acids might stimulate proximal tubular Na + reabsorption (PR/sub Na/) and thus increase RBF and GFR by a macula densa feedback mechanism. A solution of four amino acids (Ala, Ser, Gly, Pro) was infused intravenously into anesthetized dogs with normal kidneys (NK) and with kidneys in which the tubuloglomerular feedback mechanism was blunted by lowering renal artery pressure (LPK) or blocked by making the kidneys nonfiltering (NFK). In NK, RBF and GFR increased by 35 +/- 4% and 30 +/- 7% after 90 min of amino acid infusion, while PR/sub Na/ (estimated from lithium clearance) and O 2 consumption increased by 31 +/- 5% and 29 +/- 5% and distal Na + delivery remained relatively constant. Autoregulation of RBF and GFR in response to step deceases in renal artery pressure was impaired during amino acids in NK. The hemodynamic responses to amino acids were abolished in LPK and NFK. Infusion of the nonmetabolized α-aminoisobutyric acid into NK produced changes in renal hemodynamics that were similar to the responses observed with the four metabolizable amino acids. These data are consistent with the hypothesis that elevation of plasma amino acids increases RBF and GFR by a mechanism that requires an intact macula densa feedback. Metabolism of the amino acids does not appear to be necessary for these changes to occur

  14. Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Woods, L.L.; Mizelle, H.L.; Montani, J.P.; Hall, J.E.

    1986-08-01

    Our purpose was to investigate the mechanisms by which increased plasma amino acids elevate renal blood flow (RBF) and glomerular filtration rate (GFR). Since transport of amino acids and Na is linked in the proximal tubule, the authors hypothesized that increased amino acids might stimulate proximal tubular Na reabsorption (PR/sub Na/) and thus increase RBF and GFR by a macula densa feedback mechanism. A solution of four amino acids (Ala, Ser, Gly, Pro) was infused intravenously into anesthetized dogs with normal kidneys (NK) and with kidneys in which the tubuloglomerular feedback mechanism was blunted by lowering renal artery pressure (LPK) or blocked by making the kidneys nonfiltering (NFK). In NK, RBF and GFR increased by 35 +/- 4% and 30 +/- 7% after 90 min of amino acid infusion, while PR/sub Na/ (estimated from lithium clearance) and O2 consumption increased by 31 +/- 5% and 29 +/- 5% and distal Na delivery remained relatively constant. Autoregulation of RBF and GFR in response to step deceases in renal artery pressure was impaired during amino acids in NK. The hemodynamic responses to amino acids were abolished in LPK and NFK. Infusion of the nonmetabolized -aminoisobutyric acid into NK produced changes in renal hemodynamics that were similar to the responses observed with the four metabolizable amino acids. These data are consistent with the hypothesis that elevation of plasma amino acids increases RBF and GFR by a mechanism that requires an intact macula densa feedback. Metabolism of the amino acids does not appear to be necessary for these changes to occur.

  15. Hydration Control of the Mechanical and Dynamical Properties of Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Petridis, Loukas; O’Neill, Hugh M.; Johnsen, Mariah [Ripon College, Ripon, Wisconsin 54971, United States; Fan, Bingxin [Department; Schulz, Roland [Department; Mamontov, Eugene; Maranas, Janna [Department; Langan, Paul [Department; Smith, Jeremy C. [Department

    2014-10-13

    The mechanical and dynamical properties of cellulose, the most abundant biomolecule on earth, are essential for its function in plant cell walls and advanced biomaterials. Cellulose is almost always found in a hydrated state, and it is therefore important to understand how hydration influences its dynamics and mechanics. Here, the nanosecond-time scale dynamics of cellulose is characterized using dynamic neutron scattering experiments and molecular dynamics (MD) simulation. The experiments reveal that hydrated samples exhibit a higher average mean-square displacement above ~240 K. The MD simulation reveals that the fluctuations of the surface hydroxymethyl atoms determine the experimental temperature and hydration dependence. The increase in the conformational disorder of the surface hydroxymethyl groups with temperature follows the cellulose persistence length, suggesting a coupling between structural and mechanical properties of the biopolymer. In the MD simulation, 20% hydrated cellulose is more rigid than the dry form, due to more closely packed cellulose chains and water molecules bridging cellulose monomers with hydrogen bonds. This finding may have implications for understanding the origin of strength and rigidity of secondary plant cell walls. The detailed characterization obtained here describes how hydration-dependent increased fluctuations and hydroxymethyl disorder at the cellulose surface lead to enhancement of the rigidity of this important biomolecule.

  16. The Methods and Mechanisms for Access Control of Encrypted Data in Clouds

    Directory of Open Access Journals (Sweden)

    Sergey Vladimirovich Zapechnikov

    2013-09-01

    Full Text Available The paper is about the problem of data access control in clouds. The main mechanisms for access control of encrypted data in untrusted cloud environments are analyzed and described. The comparative analysis of access control algorithms and implementation issues are offered. The main practical result of research is a web-based (Wikipedia-like reference and information system devoted to the access control methods and mechanisms.

  17. A flow-control mechanism for distributed systems

    Science.gov (United States)

    Maitan, J.

    1991-01-01

    A new approach to the rate-based flow control in store-and-forward networks is evaluated. Existing methods display oscillations in the presence of transport delays. The proposed scheme is based on the explicit use of an embedded dynamic model of a store-and-forward buffer in a controller's feedback loop. It is shown that the use of the model eliminates the oscillations caused by the transport delays. The paper presents simulation examples and assesses the applicability of the scheme in the new generation of high-speed photonic networks where transport delays must be considered.

  18. Molecular mechanisms controlling proton pumping by bacteriorhodopsin. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Crouch, Rosalie K.; Ebrey, Thomas G.

    2000-02-10

    Bacteriorhodopsin (bR) is the simplest biological system for the transduction of light energy. Light energy is directly converted to transmembrane proton gradient by a single, small membrane protein. The extraordinary stability of bR makes it an outstanding subject for bioenergetic studies. This project has focused on the role of interactions between key residues of the pigment involved in light-induced proton transfer. Methods to estimate the strength of these interactions and their correlation with the rate and efficiency of proton transfer have been developed. The concept of the coupling of the protonation states of key groups has been applied to individual steps of the proton transfer with the ultimate goal of understanding on the molecular level the driving forces for proton transport and the pathway of the transported proton in bT. The mechanism of light-induced proton release, uptake and the mechanism of recovery of initial state of bT has been examined. The experiments were performed with genetically engineered, site-specific mutants of bR. This has enabled us to characterize the role of individual amino acid residues in bR. Time resolved and low temperature absorption spectroscopy and light-induced photocurrent measurements were used in order to study the photochemical cycle and proton transfer in mutant pigments. Chemical modification and crosslinking of both the specific amino acids to the chromophore or to other amino acids were used to elucidate the role of light-induced conformational changes in the photocycle and the structure of the protein in the ground state. The results of this project provided new knowledge on the architecture of the proton transfer pathways inside the protein, on the mechanism of proton release in bR, and on the role of specific amino acid residues in the structure and function of bR.

  19. Chemical and mechanical control of corrosion product transport

    Energy Technology Data Exchange (ETDEWEB)

    Hede Larsen, O; Blum, R [I/S Fynsvaerket, Faelleskemikerne, Odense (Denmark); Daucik, K [I/S Skaerbaekvaerket, Faelleskemikerne, Fredericia (Denmark)

    1996-12-01

    The corrosion products formed in the condensate and feedwater system of once-through boilers are precipitated and deposited inside the evaporator tubes mainly in the burner zone at the highest heat flux. Depositions lead to increased oxidation rate and increased metal temperature of the evaporator tubes, hereby decreasing tube lifetime. This effect is more important in the new high efficiency USC boilers due to increased feedwater temperature and hence higher thermal load on the evaporator tubes. The only way to reduce the load on the evaporator tubes is to minimise corrosion product transport to the boiler. Two general methods for minimising corrosion product transport to the boiler have been evaluated through measurement campaigns for Fe in the water/steam cycle in supercritical boilers within the ELSAM area. One method is to reduce corrosion in the low temperature condensate system by changing conditioning mode from alkaline volatile treatment (AVT) to oxygenated treatment (OT). The other method is to filtrate part of the condensate with a mechanical filter at the deaerator. The results show, that both methods are effective at minimising Fe-transport to the boiler, but changing to OT has the highest effect and should always be used, whenever high purity condensate is maintained. Whether mechanical filtration also is required, depends on the boiler, specifically the load on the evaporator. A simplified calculation model for lifetime evaluation of evaporator tubes has been developed. This model has been used for evaluating the effect of corrosion product transport to the boiler on evaporator tube lifetime. Conventional supercritical boilers generally can achieve sufficient lifetime by AVT and even better by OT, whereas all measures to reduce Fe-content of feedwater, including OT and mechanical filtration, should be taken, to ensure sufficient lifetime for the new boilers with advanced steam data - 290 bar/580 deg. C and above. (au)

  20. Control of Rock Mechanics in Underground Ore Mining

    Science.gov (United States)

    Golik, V. I.; Efremenkov, A. B.

    2017-07-01

    Performance indicators in underground mining of thick iron fields can be insufficient since geo-mechanic specifics of ore-hosting fields might be considered inadequately, as a consequence, critical deformations and even earth’s surface destruction are possible, lowering the indicators of full subsurface use, this way. The reason for it is the available approach to estimating the performance of mining according to ore excavation costs, without assessing losses of valuable components and damage to the environment. The experimental approach to the problem is based on a combination of methods to justify technical capability and performance of mining technology improvement with regard to geomechanical factors. The main idea of decisions to be taken is turning geo-materials into the condition of triaxial compression via developing the support constructions of blocked up structural rock block. The study was carried out according to an integrated approach based on the analysis of concepts, field observations, and simulation with the photo-elastic materials in conditions of North Caucasus deposits. A database containing information on the deposit can be developed with the help of industrial experiments and performance indicators of the field can be also improved using the ability of ore-hosting fields to develop support constructions, keeping the geo-mechanical stability of the system at lower cost, avoiding ore contamination at the processing stage. The proposed model is a specific one because an adjustment coefficient of natural and anthropogenic stresses is used and can be adopted for local conditions. The relation of natural to anthropogenic factors can make more precise the standards of developed, prepared and ready to excavation ore reserves relying on computational methods. It is possible to minimize critical stresses and corresponding deformations due to dividing the ore field into sectors safe from the standpoint of geo-mechanics, and using less cost

  1. Automatic detection of AutoPEEP during controlled mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Nguyen Quang-Thang

    2012-06-01

    Full Text Available Abstract Background Dynamic hyperinflation, hereafter called AutoPEEP (auto-positive end expiratory pressure with some slight language abuse, is a frequent deleterious phenomenon in patients undergoing mechanical ventilation. Although not readily quantifiable, AutoPEEP can be recognized on the expiratory portion of the flow waveform. If expiratory flow does not return to zero before the next inspiration, AutoPEEP is present. This simple detection however requires the eye of an expert clinician at the patient’s bedside. An automatic detection of AutoPEEP should be helpful to optimize care. Methods In this paper, a platform for automatic detection of AutoPEEP based on the flow signal available on most of recent mechanical ventilators is introduced. The detection algorithms are developed on the basis of robust non-parametric hypothesis testings that require no prior information on the signal distribution. In particular, two detectors are proposed: one is based on SNT (Signal Norm Testing and the other is an extension of SNT in the sequential framework. The performance assessment was carried out on a respiratory system analog and ex-vivo on various retrospectively acquired patient curves. Results The experiment results have shown that the proposed algorithm provides relevant AutoPEEP detection on both simulated and real data. The analysis of clinical data has shown that the proposed detectors can be used to automatically detect AutoPEEP with an accuracy of 93% and a recall (sensitivity of 90%. Conclusions The proposed platform provides an automatic early detection of AutoPEEP. Such functionality can be integrated in the currently used mechanical ventilator for continuous monitoring of the patient-ventilator interface and, therefore, alleviate the clinician task.

  2. Lie Algebroids in Classical Mechanics and Optimal Control

    Directory of Open Access Journals (Sweden)

    Eduardo Martínez

    2007-03-01

    Full Text Available We review some recent results on the theory of Lagrangian systems on Lie algebroids. In particular we consider the symplectic and variational formalism and we study reduction. Finally we also consider optimal control systems on Lie algebroids and we show how to reduce Pontryagin maximum principle.

  3. Control of Vibration in Mechanical Systems Using Shaped Reference Inputs

    Science.gov (United States)

    1988-01-01

    damping with several discrete actuators. Burke and Hubbard 34! generated a distributed control law by applying a piezoelectric film to the beam that...setpoints from successive memory locations. DATA-kYOVE (- starts servoing to setpoints from successive memory locations for mnicro scified by MN while taking

  4. Financing and delivery mechanisms for mosquito control tools in ...

    African Journals Online (AJOL)

    Background: Malaria is a major public health problem in Sudan and causes an enormous burden of morbidity in the country. Malaria is generally controlled in Sudan using five main approaches, which are environmental management, space spraying (SS), insecticide-treated nets (ITNs), larviciding with abate (LWA) and ...

  5. Adaptive Sliding-Mode Tracking Control for a Class of Nonholonomic Mechanical Systems

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2013-01-01

    Full Text Available This paper investigates the problem of finite-time tracking control for nonholonomic mechanical systems with affine constraints. The control scheme is provided by flexibly incorporating terminal sliding-mode control with the method of relay switching control and related adaptive technique. The proposed relay switching controller ensures that the output tracking error converges to zero in a finite time. As an application, a boat on a running river is given to show the effectiveness of the control scheme.

  6. Coupling device of the control rod and of the drive mechanism

    International Nuclear Information System (INIS)

    Savary, F.

    1986-01-01

    The invention proposes a coupling device removable in which the connection between the upper head of the control rod and the drive mechanism is a real rigid fixing, in the mechanical sense of the term, suppressing longitudinal play and allowing to restrict the momenta occurring when locating the control rods [fr

  7. 14 CFR 27.923 - Rotor drive system and control mechanism tests.

    Science.gov (United States)

    2010-01-01

    ... the position that will give maximum longitudinal cyclic pitch change to simulate forward flight. The... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rotor drive system and control mechanism....923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this section...

  8. Influences of the Control on the Nonlinear Vibrations of a Variable Compression Ratio Mechanism

    Directory of Open Access Journals (Sweden)

    Mănescu Bogdan

    2018-01-01

    Full Text Available For the mechanism described in references the study of the nonlinear vibrations is performed considering a multibody approach for the elements of the mechanism and different laws of motion for the control element. A great attention is paid to the equilibrium of the motion. The influence of different parameters of control is highlighted in the paper. The results are numerically validated.

  9. Allosteric mechanism controls traffic in the chaperone/usher pathway.

    Science.gov (United States)

    Di Yu, Xiao; Dubnovitsky, Anatoly; Pudney, Alex F; Macintyre, Sheila; Knight, Stefan D; Zavialov, Anton V

    2012-11-07

    Many virulence organelles of Gram-negative bacterial pathogens are assembled via the chaperone/usher pathway. The chaperone transports organelle subunits across the periplasm to the outer membrane usher, where they are released and incorporated into growing fibers. Here, we elucidate the mechanism of the usher-targeting step in assembly of the Yersinia pestis F1 capsule at the atomic level. The usher interacts almost exclusively with the chaperone in the chaperone:subunit complex. In free chaperone, a pair of conserved proline residues at the beginning of the subunit-binding loop form a "proline lock" that occludes the usher-binding surface and blocks usher binding. Binding of the subunit to the chaperone rotates the proline lock away from the usher-binding surface, allowing the chaperone-subunit complex to bind to the usher. We show that the proline lock exists in other chaperone/usher systems and represents a general allosteric mechanism for selective targeting of chaperone:subunit complexes to the usher and for release and recycling of the free chaperone. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Control of distributed heat transfer mechanisms in membrane distillation plants

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2017-01-05

    Various examples are provided that are related to boundary control in membrane distillation (MD) processes. In one example, a system includes a membrane distillation (MD) process comprising a feed side and a permeate side separated by a membrane boundary layer; and processing circuitry configured to control a water production rate of the MD process based at least in part upon a distributed heat transfer across the membrane boundary layer. In another example, a method includes determining a plurality of estimated temperature states of a membrane boundary layer separating a feed side and a permeate side of a membrane distillation (MD) process; and adjusting inlet flow rate or inlet temperature of at least one of the feed side or the permeate side to maintain a difference temperature along the membrane boundary layer about a defined reference temperature based at least in part upon the plurality of estimated temperature states.

  11. Sexual orientation biases attentional control: a possible gaydar mechanism

    Directory of Open Access Journals (Sweden)

    Lorenza S Colzato

    2010-05-01

    Full Text Available Homosexuals are believed to have a “sixth sense” for recognizing each other, an ability referred to as gaydar. We considered that being a homosexual might rely on systematic practice of processing relatively specific, local perceptual features, which might lead to a corresponding chronic bias of attentional control. This was tested by comparing male and female homosexuals and heterosexuals--brought up in the same country and culture and matched in terms of race, intelligence, sex, mood, age, personality, religious background, educational style, and socio-economic situation--in their efficiency to process global and local features of hierarchically-constructed visual stimuli. Both homosexuals and heterosexuals showed better performance on global features—the standard global precedence effect. However, this effect was significantly reduced in homosexuals, suggesting a relative preference for detail. Findings are taken to demonstrate chronic, generalized biases in attentional control parameters that reflect the selective reward provided by the respective sexual orientation.

  12. Mechanical design of an electronic control unit using axiomatic principles

    Directory of Open Access Journals (Sweden)

    Cazacu Vlad

    2017-01-01

    Full Text Available If the engine of the car can be considered as the heart, then the E.C.U’s represents the brain of the car. Electronic control units (E.C.U’s are electronic devices which control the way different components of a car (engine, windows, airbags, etc. react in some situations (overheating, button pressed by a passenger, crash, etc.. Axiomatic design is a set of principles that theorizes the act of conceiving a new project. Based on two axiom this method comes into designers help, giving them the option to reach in a short period of time a fully functional and compliant product without supporting the design of the product on chance, past experiences or “try and fail” principle.

  13. Molecular Mechanisms to Control Post-Transplantation Hepatitis B Recurrence

    Directory of Open Access Journals (Sweden)

    Akinobu Takaki

    2015-07-01

    Full Text Available Hepatitis B often progresses to decompensated liver cirrhosis requiring orthotopic liver transplantation (OLT. Although newer nucleos(tide analogues result in >90% viral and hepatitis activity control, severely decompensated patients still need OLT because of drug-resistant virus, acute exacerbation, or hepatocellular carcinoma. Acute hepatitis B is also an indication for OLT, because it can progress to fatal acute liver failure. After OLT, the hepatitis B recurrence rate is >80% without prevention, while >90% of transplant recipients are clinically controlled with combined hepatitis B immunoglobulin (HBIG and nucleos(tide analogue treatment. However, long-term HBIG administration is associated with several unresolved issues, including limited availability and extremely high cost; therefore, several treatment protocols with low-dose HBIG, combined with nucleos(tide analogues, have been investigated. Another approach is to induce self-producing anti-hepatitis B virus (HBV antibodies using an HBV envelope (HBs antigen vaccine. Patients who are not HBV carriers, such as those with acutely infected liver failure, are good candidates for vaccination. For chronic HBV carrier liver cirrhosis patients, a successful vaccine response can only be achieved in selected patients, such as those treated with experimentally reduced immunosuppression protocols. The present protocol for post-OLT HBV control and the future prospects of newer treatment strategies are reviewed.

  14. Factors controlling alkalisalt deposition in recovery boiler- release mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    McKeough, P.; Kylloenen, H.; Kurkela, M. [VTT Energy, Espoo (Finland). Process Technology Group

    1996-12-01

    As part of a cooperative effort to develop a model to describe the behaviour of inorganic compounds in kraft recovery boilers, an experimental investigation of the release of sulphur during black liquor pyrolysis has been undertaken. Previous to these studies, the mechanisms of sulphur release and the reasons for the observed effects of process conditions on sulphur release were very poorly understood. On the basis of the experimental results, the main reactions leading to sulphur release have been elucidated with a fair degree of certainty. Logical explanations for the variations of sulphur release with temperature and with liquor solids content have been proposed. The influence of pressure has been investigated in order to gain insights into the effects of mass transfer on the sulphur-release rate. In the near future, the research will be aimed at generating the kinetic data necessary for modelling the release of sulphur in the recovery furnace. (author)

  15. Mechanisms of surgical control of type 2 diabetes

    DEFF Research Database (Denmark)

    Holst, Jens Juul; Madsbad, Sten

    2016-01-01

    of the operation, is reduced and or abolished after GLP-1 receptor blockade. Also the postoperative improvement of glucose tolerance is eliminated and or reduced by the antagonist, pointing to a key role for the exaggerated GLP-1 secretion. Indeed, there is evidence that the exaggerated GLP-1 secretion is also......GLP-1 secretion in response to meals is dramatically increased after gastric bypass operations. GLP-1 is a powerful insulinotropic and anorectic hormone, and analogs of GLP-1 are widely used for the treatment of diabetes and recently approved also for obesity treatment. It is, therefore, reasonable...... responsible for postprandial hypoglycemia sometimes observed after bypass. Other operations (biliopancreatic-diversion and or sleeve gastrectomy) appear to involve different and/or additional mechanisms, and so does experimental bariatric surgery in rodents. However, unlike bypass surgery in humans...

  16. Universal entrainment mechanism controls contact times with motile cells

    Science.gov (United States)

    Mathijssen, Arnold J. T. M.; Jeanneret, Raphaël; Polin, Marco

    2018-03-01

    Contact between particles and motile cells underpins a wide variety of biological processes, from nutrient capture and ligand binding to grazing, viral infection, and cell-cell communication. The window of opportunity for these interactions depends on the basic mechanism determining contact time, which is currently unknown. By combining experiments on three different species—Chlamydomonas reinhardtii, Tetraselmis subcordiforms, and Oxyrrhis marina—with simulations and analytical modeling, we show that the fundamental physical process regulating proximity to a swimming microorganism is hydrodynamic particle entrainment. The resulting distribution of contact times is derived within the framework of Taylor dispersion as a competition between advection by the cell surface and microparticle diffusion, and predicts the existence of an optimal tracer size that is also observed experimentally. Spatial organization of flagella, swimming speed, and swimmer and tracer size influence entrainment features and provide tradeoffs that may be tuned to optimize the estimated probabilities for microbial interactions like predation and infection.

  17. Regulatory Mechanisms Controlling Maturation of Serotonin Neuron Identity and Function.

    Science.gov (United States)

    Spencer, William C; Deneris, Evan S

    2017-01-01

    The brain serotonin (5-hydroxytryptamine; 5-HT) system has been extensively studied for its role in normal physiology and behavior, as well as, neuropsychiatric disorders. The broad influence of 5-HT on brain function, is in part due to the vast connectivity pattern of 5-HT-producing neurons throughout the CNS. 5-HT neurons are born and terminally specified midway through embryogenesis, then enter a protracted period of maturation, where they functionally integrate into CNS circuitry and then are maintained throughout life. The transcriptional regulatory networks controlling progenitor cell generation and terminal specification of 5-HT neurons are relatively well-understood, yet the factors controlling 5-HT neuron maturation are only recently coming to light. In this review, we first provide an update on the regulatory network controlling 5-HT neuron development, then delve deeper into the properties and regulatory strategies governing 5-HT neuron maturation. In particular, we discuss the role of the 5-HT neuron terminal selector transcription factor (TF) Pet-1 as a key regulator of 5-HT neuron maturation. Pet-1 was originally shown to positively regulate genes needed for 5-HT synthesis, reuptake and vesicular transport, hence 5-HT neuron-type transmitter identity. It has now been shown to regulate, both positively and negatively, many other categories of genes in 5-HT neurons including ion channels, GPCRs, transporters, neuropeptides, and other transcription factors. Its function as a terminal selector results in the maturation of 5-HT neuron excitability, firing characteristics, and synaptic modulation by several neurotransmitters. Furthermore, there is a temporal requirement for Pet-1 in the control of postmitotic gene expression trajectories thus indicating a direct role in 5-HT neuron maturation. Proper regulation of the maturation of cellular identity is critical for normal neuronal functioning and perturbations in the gene regulatory networks controlling

  18. Development of passive-controlled HUB (teetered brake & damper mechanism) of horizontal axis wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Yukimaru; Kamada, Yasunari; Maeda, Takao [Mie Univ. (Japan)

    1997-12-31

    For the purpose of the improvement of reliability of the Mega-Watt wind turbine, this paper indicates the development of an original mechanism for the passive-controlled hub, which has the effects of braking and damping on aerodynamic forces. This mechanism is useful for variable speed control of the large wind turbine. The passive-controlled hub is the combination of two mechanisms. One is the passive-teetered and damping mechanism, and the other is the passive-variable-pitch mechanism. These mechanism are carried out by the combination of the teetering and feathering motions. When the wind speed exceeds the rated wind speed, the blade is passively teetered in a downwind direction and, simultaneously, a feathering mechanism, which is linked to the teetering mechanism through a connecting rods, is activated. Testing of the model horizontal axis wind turbine in a wind tunnel showed that the passive-controlled hub mechanism can suppress the over-rotational speed of the rotor. By the application of the passive-controlled hub mechanism, the maximum rotor speed is reduced to about 60%.

  19. Environmental Effects on the Photophysics of Organic-Inorganic Halide Perovskites.

    Science.gov (United States)

    Galisteo-López, Juan F; Anaya, M; Calvo, M E; Míguez, H

    2015-06-18

    The photophysical properties of films of organic-inorganic lead halide perovskites under different ambient conditions are herein reported. We demonstrate that their luminescent properties are determined by the interplay between photoinduced activation and darkening processes, which strongly depend on the atmosphere surrounding the samples. We have isolated oxygen and moisture as the key elements in each process, activation and darkening, both of which involve the interaction with photogenerated carriers. These findings show that environmental factors play a key role in the performance of lead halide perovskites as efficient luminescent materials.

  20. Formation of the controlling mechanism in the management of innovative development of enterprise potential

    Directory of Open Access Journals (Sweden)

    Андрій Анатолійович Пилипенко

    2015-11-01

    Full Text Available The article presents the guidelines for the formation of the controlling mechanism in the activation cycles of innovative activities and the formation of the development programs of the enterprise potential. It is offered understanding the development potential and proved grouping of controlled performance, taking into account the level of innovation ability of the enterprise. It is presented the strategic matrix of determining the composition of performance, determination of monitoring parameters and aspects of controlling mechanism

  1. Qualification tests for PWR control element drive mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Yong; Jin, Choon Eon; Choi Suhn [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-01-01

    It is necessary to perform the qualification test for the magnetic jack type CEDM to show the design compatibility because the CEDM is composed of many mechanical and electrical components complicatedly. ABB-CE performed various qualification tests during the development of the System80 CEDM to which Korea Standard Nuclear Plant (KSNP) CEDM referred. The qualification test for the CEDM is classified into the performance test and the dynamic test. The performance test is to verify operability of the CEDM, and the dynamic test is to find dynamic characteristics and to verify the structural integrity if the CEDM for the seismic accidents. Described in this report are the test requirements, the test facilities and the test methods for the performance and the dynamic qualification tests of the PWR magnetic jack type CEDM. The impacts of the design changes in the Korea Next Generation Reactor (KNGR) on the KSNP CEDM were analyzed to present the necessity for the tests. This report also proposes the facilities to perform the tests in KAERI including reasonable schedule for the tests. Attached to this report is the summary of qualification tests of System 80 CEDM performed by ABB-CE. 20 figs., 16 tabs., 21 refs. (Author) .new.

  2. Qualification tests for PWR control element drive mechanism

    International Nuclear Information System (INIS)

    Kim, In Yong; Jin, Choon Eon; Choi Suhn

    1996-01-01

    It is necessary to perform the qualification test for the magnetic jack type CEDM to show the design compatibility because the CEDM is composed of many mechanical and electrical components complicatedly. ABB-CE performed various qualification tests during the development of the System80 CEDM to which Korea Standard Nuclear Plant (KSNP) CEDM referred. The qualification test for the CEDM is classified into the performance test and the dynamic test. The performance test is to verify operability of the CEDM, and the dynamic test is to find dynamic characteristics and to verify the structural integrity if the CEDM for the seismic accidents. Described in this report are the test requirements, the test facilities and the test methods for the performance and the dynamic qualification tests of the PWR magnetic jack type CEDM. The impacts of the design changes in the Korea Next Generation Reactor (KNGR) on the KSNP CEDM were analyzed to present the necessity for the tests. This report also proposes the facilities to perform the tests in KAERI including reasonable schedule for the tests. Attached to this report is the summary of qualification tests of System 80 CEDM performed by ABB-CE. 20 figs., 16 tabs., 21 refs. (Author) .new

  3. Online payload estimation for the control of underactuated mechanical systems

    International Nuclear Information System (INIS)

    Lu, Yu Sheng; Chiu, Hua Hsu

    2014-01-01

    This paper presents a payload estimation scheme for underactuated robotic manipulators with passive joints that are not driven by actuators. In the proposed scheme, only the payload, which can be quite uncertain when a robot performs various tasks, is estimated, because the manipulator's electrical and other mechanical parameters are generally known in advance. In comparison to other adaptive schemes for underactuated robotic manipulators, the proposed scheme produces satisfactory transient performance and also reduces the computational burden in real-time implementation. The proposed estimation law is also based on the theory of Variable Structure Systems. In contrast to existing adaptation laws that have an integral form, the proposed law estimates uncertain payload using lowpass filtering of a switching signal that is always bounded, which avoids the parameter-drifting problem that is often encountered when using the previous integral laws. Real-time experiments are conducted using an inverted pendulum and the experimental results demonstrate the feasibility and effectiveness of the proposed scheme.

  4. Multiple cognitive control mechanisms associated with the nature of conflict.

    Science.gov (United States)

    Kim, Chobok; Chung, Chongwook; Kim, Jeounghoon

    2010-06-07

    Cognitive control is required to regulate conflict. The conflict monitoring theory suggests that the dorsal anterior cingulate cortex (dACC) is involved in detecting response conflict and the dorsolateral prefrontal cortex (DLPFC) plays a critical role in regulating conflict. Recent studies, however, have suggested that rostral dACC (rdACC) responds to response conflict whereas caudal dACC (cdACC) is associated with perceptual conflict. Moreover, DLPFC has been engaged only in regulation of response conflict. A neural network involved in perceptual conflict, however, remains unclear. In this study, we used functional magnetic resonance imaging (fMRI) in an attempt to reveal monitor-controller networks corresponding to either perceptual conflict or response conflict. A version of the Stroop color matching task was used to manipulate perceptual conflict, response conflict was manipulated by an arrow. The results demonstrated that rdACC and DLPFC were engaged in response conflict whereas cdACC and the dorsal portion of premotor cortex (pre-PMd) were involved in perceptual conflict. Interestingly, the posterior parietal cortex (PPC) was activated by both types of conflict. Correlation analyses between behavioral conflict effects and neural responses demonstrated that rdACC and DLPFC were associated with response conflict whereas cdACC and pre-PMd were associated with perceptual conflict. PPC was not correlated with either perceptual conflict or response conflict. We suggest that cdACC and pre-PMd play critical roles in perceptual conflict processing, and this network is independent from the rdACC/DLPFC network for response conflict processing. We also discussed the function of PPC in conflict processing. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  5. Radial basis function (RBF) neural network control for mechanical systems design, analysis and Matlab simulation

    CERN Document Server

    Liu, Jinkun

    2013-01-01

    Radial Basis Function (RBF) Neural Network Control for Mechanical Systems is motivated by the need for systematic design approaches to stable adaptive control system design using neural network approximation-based techniques. The main objectives of the book are to introduce the concrete design methods and MATLAB simulation of stable adaptive RBF neural control strategies. In this book, a broad range of implementable neural network control design methods for mechanical systems are presented, such as robot manipulators, inverted pendulums, single link flexible joint robots, motors, etc. Advanced neural network controller design methods and their stability analysis are explored. The book provides readers with the fundamentals of neural network control system design.   This book is intended for the researchers in the fields of neural adaptive control, mechanical systems, Matlab simulation, engineering design, robotics and automation. Jinkun Liu is a professor at Beijing University of Aeronautics and Astronauti...

  6. Photophysical properties of columnar phases formed by triphenylene derivatives

    International Nuclear Information System (INIS)

    Sigal, Herve

    1997-01-01

    This research thesis reports the study of the spectroscopic properties and of the migration of excitation energy in the singlet state in columnar phases formed by alkyloxy and alkylthio derivatives of triphenylene. First, the author studied the spectroscopic properties of chromophores in solutions, and characterized excited states by using computation codes (CS-INDO-CIPSI). Then, by using the excitonic theory in the case of the considered triphenylene derivatives, the author studied the influence of molecular movements and of the intra-columnar order on the spectroscopic properties. In some circumstances, the non-radiative transfer of excitation energy is governed by a mechanism displaying a random evolution. This stochastic movement is studied by using Monte Carlo simulations. The author shows that the energy migration is one-dimensional on short times, and then becomes three-dimensional. The evolution of excitation energy in space and in time is determined [fr

  7. Quantum ground state and single-phonon control of a mechanical resonator.

    Science.gov (United States)

    O'Connell, A D; Hofheinz, M; Ansmann, M; Bialczak, Radoslaw C; Lenander, M; Lucero, Erik; Neeley, M; Sank, D; Wang, H; Weides, M; Wenner, J; Martinis, John M; Cleland, A N

    2010-04-01

    Quantum mechanics provides a highly accurate description of a wide variety of physical systems. However, a demonstration that quantum mechanics applies equally to macroscopic mechanical systems has been a long-standing challenge, hindered by the difficulty of cooling a mechanical mode to its quantum ground state. The temperatures required are typically far below those attainable with standard cryogenic methods, so significant effort has been devoted to developing alternative cooling techniques. Once in the ground state, quantum-limited measurements must then be demonstrated. Here, using conventional cryogenic refrigeration, we show that we can cool a mechanical mode to its quantum ground state by using a microwave-frequency mechanical oscillator-a 'quantum drum'-coupled to a quantum bit, which is used to measure the quantum state of the resonator. We further show that we can controllably create single quantum excitations (phonons) in the resonator, thus taking the first steps to complete quantum control of a mechanical system.

  8. Overflow control mechanism (OCM) for Ethernet passive optical networks (EPONs)

    Science.gov (United States)

    Hajduczenia, Marek; da Silva, Henrique J. A.; Monteiro, Paulo P.

    2007-05-01

    The nonfragmentable nature of Ethernet data frames, as well as operation of the priority oriented packet schedulers in the optical network units, in conjunction with heavy network load conditions and the lack of detailed knowledge about the queue's composition at the optical line terminal (OLT) level, result in the creation of upstream channel slot remainders. The existing methods, in the form of nonpreemptive packet schedulers and multithreshold reporting process defined vaguely by the IEEE 802.3-2005 standard, result in either increased packet delay or Ethernet passive optical network (EPON) system incompatibility, respectively, since threshold processing was never officially defined in the scope of the respective EPON standard. We propose an alternative approach, based on basic modifications of the standard and extended GATE multipoint control protocol data unit format and meaning, allowing for the OLT packet scheduling agent to grant always exactly the requested slot size, thus preventing creation of any upstream channel slot remainders. It is estimated that, on average, ˜3% of upstream channel bandwidth can be salvaged when slot remainders are absent in the upstream channel transmission.

  9. Performance Analysis of Novel Overload Control with Threshold Mechanism

    Directory of Open Access Journals (Sweden)

    Doo Il Choi

    2016-01-01

    Full Text Available We propose a novel overload control method with hysteresis property; that is, we analyze the M/G/1/K queueing system where the service and arrival rates are varied depending on the queue-length. We use two threshold values: L1(≤L2 and L2(≤K. When the queue-length increases by an amount between L1 and L2, we apply one of the following two strategies to reduce the queue-length, either we decrease the mean service time or we decrease the arrival rate. If the queue-length exceeds L2 with one strategy, we apply the other; thus, there are two models that depend on the method that was applied first. We derive the queue-length distribution at departure and at arbitrary epochs using the embedded Markov chain method and the supplementary variable method. We investigate performance measures including the loss probability and mean waiting time using various numerical examples.

  10. Endocrine control of epigenetic mechanisms in male reproduction.

    Science.gov (United States)

    Ankolkar, Mandar; Balasinor, N H

    2016-01-01

    Endocrine control of reproduction is very well known and has been echoed by many research groups. However, recent developments point to the ability of toxic endocrine disrupting chemicals (EDC) to alter epigenetic information of the gametes which gets transferred to the developing embryo and affects the immediate reproductive outcome or even persists transgenerationally. These epigenetic aberrations contribute to the ensuing pathophysiology of reproductive disorders. Investigations of the female in cases of poor reproductive outcome have been the main strategy towards diagnosis. However, despite the male partner contributing half of his genome to the progeny, thorough investigations in the male have been ignored. Environmental pollutants are all pervading and are encountered in our day-to-day life. Many of these pollutants have potential to disrupt the endocrine system. Here, we discuss how the male gametes (spermatozoa) are susceptible to a myriad of epigenetic insults inflicted by exposure to endocrine disruptors and how important is the contribution of the epigenetic marks of the spermatozoa in healthy reproduction. We advocate that sperm epigenetics should be considered as a significant contributor to reproductive health and should be researched further and be subsequently included in routine diagnostic workup in cases of poor reproductive outcome.

  11. Stochastic Optimal Control for Online Seller under Reputational Mechanisms

    Directory of Open Access Journals (Sweden)

    Milan Bradonjić

    2015-12-01

    Full Text Available In this work we propose and analyze a model which addresses the pulsing behavior of sellers in an online auction (store. This pulsing behavior is observed when sellers switch between advertising and processing states. We assert that a seller switches her state in order to maximize her profit, and further that this switch can be identified through the seller’s reputation. We show that for each seller there is an optimal reputation, i.e., the reputation at which the seller should switch her state in order to maximize her total profit. We design a stochastic behavioral model for an online seller, which incorporates the dynamics of resource allocation and reputation. The design of the model is optimized by using a stochastic advertising model from [1] and used effectively in the Stochastic Optimal Control of Advertising [2]. This model of reputation is combined with the effect of online reputation on sales price empirically verified in [3]. We derive the Hamilton-Jacobi-Bellman (HJB differential equation, whose solution relates optimal wealth level to a seller’s reputation. We formulate both a full model, as well as a reduced model with fewer parameters, both of which have the same qualitative description of the optimal seller behavior. Coincidentally, the reduced model has a closed form analytical solution that we construct.

  12. Block backstepping design of nonlinear state feedback control law for underactuated mechanical systems

    CERN Document Server

    Rudra, Shubhobrata; Maitra, Madhubanti

    2017-01-01

    This book presents a novel, generalized approach to the design of nonlinear state feedback control laws for a large class of underactuated mechanical systems based on application of the block backstepping method. The control law proposed here is robust against the effects of model uncertainty in dynamic and steady-state performance and addresses the issue of asymptotic stabilization for the class of underactuated mechanical systems. An underactuated system is defined as one for which the dimension of space spanned by the configuration vector is greater than that of the space spanned by the control variables. Control problems concerning underactuated systems currently represent an active field of research due to their broad range of applications in robotics, aerospace, and marine contexts. The book derives a generalized theory of block backstepping control design for underactuated mechanical systems, and examines several case studies that cover interesting examples of underactuated mechanical systems. The math...

  13. Seismic appraisal test of control rod drive mechanism of China experiment fast reactor

    International Nuclear Information System (INIS)

    Song Qing; Yang Hongyi; Jing Yueqing; Wen Jing; Liu Guijuan; Sun Lei

    2008-01-01

    The structure of the control rod drive mechanism in pool type sodium-cooled fast reactor is the characterized by long, thin, and geometric nonlinearity, and the seismic load is multiple activation. The anti-seismic evaluation is always paid great attention by the countries developing the technology worldwide. This article introduces the seismic appraisal test of the control rod drive mechanism of China Experimental Fast Reactor (CEFR) performed on a seismic platform which is vertical shaft style and multiple activation. The result of the test shows the structural integrity and the function of the control rod drive mechanism could meet the design requirements of the earthquake intensity. (authors)

  14. Interleukin 4: signalling mechanisms and control of T cell differentiation.

    Science.gov (United States)

    Paul, W E

    1997-01-01

    Interleukin 4 (IL-4) is a pleiotropic type I cytokine that controls both growth and differentiation among haemopoietic and non-haemopoietic cells. Its receptor is a heterodimer. One chain, the IL-4R alpha chain, binds IL-4 with high affinity and determines the nature of the biochemical signals that are induced. The second chain, gamma c, is required for the induction of such signals. IL-4-mediated growth depends upon activation events that involve phosphorylation of Y497 of IL-4R alpha, leading to the binding and phosphorylation of 4PS/IRS-2 in haemopoietic cells and of IRS-1 in non-haemopoietic cells. By contrast, IL-4-mediated differentiation events depend upon more distal regions of the IL-4R alpha chain that include a series of STAT-6 binding sites. The distinctive roles of these receptor domains was verified by receptor-reconstruction experiments. The 'growth' and 'differentiation' domains of the IL-4R alpha chain, independently expressed as chimeric structures with a truncated version of the IL-2R beta chain, were shown to convey their functions to the hybrid receptor. The critical role of STAT-6 in IL-4-mediated gene activation and differentiation was made clear by the finding that lymphocytes from STAT-6 knockout mice are strikingly deficient in these functions but have retained the capacity to grow, at least partially, in response to IL-4. IL-4 plays a central role in determining the phenotype of naive CD4+ T cells. In the presence of IL-4, newly primed naive T cells develop into IL-4 producers while in its absence they preferentially become gamma-interferon (IFN-gamma) producers. Recently, a specialized subpopulation of T cells, CD4+/NK1.1+ cells, has been shown to produce large amounts of IL-4 upon stimulation. Two examples of mice with deficiencies in these cells are described--beta 2-microglobulin knockout mice and SJL mice. Both show defects in the development of IL-4-producing cells and in the increase in serum IgE in response to stimulation with the

  15. On the photophysics and photochemistry of the water dimer

    Energy Technology Data Exchange (ETDEWEB)

    Segarra-Marti, Javier; Merchan, Manuela [Instituto de Ciencia Molecular, Universitat de Valencia, P.O. Box 22085, 46071 Valencia (Spain); Roca-Sanjuan, Daniel; Lindh, Roland [Department of Chemistry - Angstroem, Theoretical Chemistry Program, Uppsala University, Box 518, 75120 Uppsala (Sweden)

    2012-12-28

    The photochemistry of the water dimer irradiated by UV light is studied by means of the complete active space perturbation theory//complete active space self-consistent field (CASPT2//CASSCF) method and accurate computational approaches like as minimum energy paths. Both electronic structure computations and ab initio molecular dynamics simulations are carried out. The results obtained show small shifts relative to a single water molecule on the vertical excitation energies of the dimer due to the hydrogen bond placed between the water donor (W{sub D}) and the water acceptor (W{sub A}). A red-shift and a blue-shift are predicted for the W{sub D} and W{sub A}, respectively, supporting previous theoretical and experimental results. The photoinduced chemistry of the water dimer is described as a process occurring between two single water molecules in which the effect of the hydrogen bond plays a minor role. Thus, the photoinduced decay routes correspond to two photodissociation processes, one for each water molecule. The proposed mechanism for the decay channels of the lowest-lying excited states of the system is established as the photochemical production of a hydrogen-bonded H{sub 2}O Horizontal-Ellipsis HO species plus a hydrogen H atom.

  16. Photophysics of the excited uranyl ion in aqueous solutions

    International Nuclear Information System (INIS)

    Formosinho, S.J.; Miguel, M. da G.M.

    1985-01-01

    The effect of the micelles of Triton X-100 on the biexponential decay of (UO 2 2+ )* has been investigated. Data are analysed in terms of a reversible crossing mechanism for the decay. Azulene fluorescence quenching and 13 C n.m.r. studies strongly suggest that uranyl ions are able to penetrate deep inside the micelle core. Micelle quenching for the reversible decay of (UO 2 2+ )* occurs in the interior (ksub(q) = 3 x 10 10 dm 3 mol -1 s -1 ) and at the surface (Ksub(q) = 1.5 x 10 9 mol -1 dm 3 s -1 ) of the micelles. The latter process has a rate virtually identical to that for the free surfactant molecules. Penetration of (UO 2 2+ )* inside the non-polar regions of the micelle core increases solvent exchange rates by ca. two orders of magnitude. Uranyl-ion excimers are formed in occupied micelles. The quenching processes decrease strongly for these species because excimers do not penetrate the micelles. (author)

  17. Specific solvent effect on lumazine photophysics: A combined fluorescence and intrinsic reaction coordinate analysis

    Energy Technology Data Exchange (ETDEWEB)

    Moyon, N. Shaemningwar; Gashnga, Pynsakhiat Miki; Phukan, Smritakshi; Mitra, Sivaprasad, E-mail: smitra@nehu.ac.in

    2013-06-27

    Highlights: • Correlation of lumazine photophysics with multiparametric Kamlet–Taft equation. • Solvent basicity (β) contributes maximum towards the hydrogen bonding (HB) effect. • HB interaction occurs at N1 and N3 proton in S{sub 0} and S{sub 1} state, respectively. • IRC calculation for different tautomerization processes both in S{sub 0} and S{sub 1} states. • Process related to riboflavin biosynthesis is thermodynamically feasible. - Abstract: The photophysical properties and tautomerization behavior of neutral lumazine were studied by fluorescence spectroscopy and density functional theory calculation. A quantitative estimation of the contributions from different solvatochromic parameters, like solvent polarizibility (π{sup ∗}), hydrogen bond donation (α) and hydrogen bond accepting (β) ability of the solvent, was made using linear free energy relationships based on the Kamlet–Taft equation. The analysis reveals that the hydrogen bond acceptance ability of the solvent is the most important parameter characterizing the excited state behavior of lumazine. Theoretical calculations result predict an extensive charge redistribution of lumazine upon excitation corresponding to the N3 and N1 proton dissociation sites by solvents in the ground and excited states, respectively. Comparison of S{sub 0} and S{sub 1} state potential energy curves constructed for several water mediated tautomerization processes by intrinsic reaction coordinate analysis of lumazine-H{sub 2}O cluster shows that (3,2) and (1,8) hydrogen migrations are the most favorable processes upon excitation.

  18. Type II photoinitiator substituted zinc phthalocyanine: Synthesis, photophysical and photopolymerization studies

    Energy Technology Data Exchange (ETDEWEB)

    Korkut, Sibel Eken [Department of Chemistry, Yıldız Technical University, 34210 Davutpaşa, İstanbul (Turkey); Temel, Gokhan [Department of Polymer Engineering, Yalova University, 77100 Yalova (Turkey); Balta, Demet Karaca [Department of Chemistry, Yıldız Technical University, 34210 Davutpaşa, İstanbul (Turkey); Arsu, Nergis, E-mail: narsu@yildiz.edu.tr [Department of Chemistry, Yıldız Technical University, 34210 Davutpaşa, İstanbul (Turkey); Şener, M. Kasım, E-mail: mkasimsener@gmail.com [Department of Chemistry, Yıldız Technical University, 34210 Davutpaşa, İstanbul (Turkey)

    2013-04-15

    The novel 4-(9-oxo-9 H-thioxanthen-2yloxy) phthalonitrile (TX-Pht) and its peripherally tetra substituted zinc phthalocyanine complex (TX-ZnPc) have been prepared and characterized by spectroscopic and elemental analysis techniques. Photoinitiated polymerization of methyl methacrylate (MMA) with TX-ZnPc has been investigated in the presence and absence of a co-initiator. Fluorescence and phosphorescence measurements have been also performed to determine the photophysical properties. Low fluorescence quantum yield (Φ{sub F}=0.08) compared to the unsubstituted ZnPc has been found. This allows initiator to undergo intersystem crossing into the triplet state and the lowest triplet state possesses π-π{sup ⁎} configuration. Highlights: ► Zinc phthalocyanine (ZnPc), peripherally functionalized with photoactive thioxanthone (TX) groups was synthesized. ► The photophysical and photochemical properties of resulting photoinitiator were studied in DMF. ► Photoinitiated polymerization of MMA with TX-ZnPc was investigated in the presence and absence of co-initiator.

  19. Theory of interfacial charge-transfer complex photophysics in π-conjugated polymer-fullerene blends

    Science.gov (United States)

    Aryanpour, K.; Psiachos, D.; Mazumdar, S.

    2010-03-01

    We present a theory of the electronic structure and photophysics of 1:1 blends of derivatives of polyparaphenylenevinylene and fullerenes [1]. Within the same Coulomb-correlated Hamiltonian applied previously to interacting chains of single-component π-conjugated polymers [2], we find an exciplex state that occurs below the polymer's optical exciton. Weak absorption from the ground state occurs to the exciplex. We explain transient photoinduced absorptions in the blend [3], observed for both above-gap and below-gap photoexcitations, within our theory. Photoinduced absorptions for above-gap photoexcitation are from the optical exciton as well as the exciplex, while for below-gap photoexcitation induced absorptions are from the exciplex alone. In neither case are free polarons generated in the time scale of the experiment. Importantly, the photophysics of films of single-component π-conjugated polymers and blends can both be understood by extending Mulliken's theory of ground state charge-transfer to the case of excited state charge-transfer. [1] K. Aryanpour, D. Psiachos, and S. Mazumdar, arXiv:0908.0366 [2] D. Psiachos and S. Mazumdar, Phys. Rev. B. 79 155106 (2009) [3] T. Drori et al., Phys. Rev. Lett. 101, 037402 (2008)

  20. Synthesis, spectral and photophysical properties of novel phthalocyanines bearing bulky phenantroxy moiety

    International Nuclear Information System (INIS)

    Erdogmuş, Ali; Lütfi Ugur, Ahmet; Memişoglu, Abdussamed; Erden, İbrahim

    2013-01-01

    The synthesis, characterization, spectral and photophysical properties of soluble 9-Phenanthroxy substituted oxo-titanium (IV), zinc, magnesium and nickel phthalocyanines (1a, 1b, 1c and 1d) are reported for the first time. The new compounds have been characterized by elemental analysis, FT-IR, 1 H–NMR spectroscopy, electronic spectroscopy and mass spectra. General trends are described for spectral, fluorescence properties and fluorescence quantum yields of these compounds in dimethylsulfoxide (DMSO) and toluene. All phthalocyanine complexes (1a to 1d) exhibited excellent solubility in organic solvents such as dichloromethane, chloroform, THF, toluene, DMF and DMSO. - Highlights: ► New metallophthalocyanines (1a–1d) were synthesized. ► These new phthalocyanine derivatives show the enhanced solubility in organic solvents. ► The spectral and photophysical properties of TiO(IV), zinc (II) and Mg(II) phthalocyanine (1a–1c) are investigated in DMSO and toluene. ► Ground state electronic absorption and fluorescence spectra.

  1. Photophysics and electrochemistry relevant to photocatalytic water splitting involved at solid–electrolyte interfaces

    KAUST Repository

    Shinagawa, Tatsuya

    2016-08-04

    Direct photon to chemical energy conversion using semiconductor-electrocatalyst-electrolyte interfaces has been extensively investigated for more than a half century. Many studies have focused on screening materials for efficient photocatalysis. Photocatalytic efficiency has been improved during this period but is not sufficient for industrial commercialization. Detailed elucidation on the photocatalytic water splitting process leads to consecutive six reaction steps with the fundamental parameters involved: The photocatalysis is initiated involving photophysics derived from various semiconductor properties (1: photon absorption, 2: exciton separation). The generated charge carriers need to be transferred to surfaces effectively utilizing the interfaces (3: carrier diffusion, 4: carrier transport). Consequently, electrocatalysis finishes the process by producing products on the surface (5: catalytic efficiency, 6: mass transfer of reactants and products). Successful photocatalytic water splitting requires the enhancement of efficiency at each stage. Most critically, a fundamental understanding of the interfacial phenomena is highly desired for establishing "photocatalysis by design" concepts, where the kinetic bottleneck within a process is identified by further improving the specific properties of photocatalytic materials as opposed to blind material screening. Theoretical modeling using the identified quantitative parameters can effectively predict the theoretically attainable photon-conversion yields. This article provides an overview of the state-of-the-art theoretical understanding of interfacial problems mainly developed in our laboratory. Photocatalytic water splitting (especially hydrogen evolution on metal surfaces) was selected as a topic, and the photophysical and electrochemical processes that occur at semiconductor-metal, semiconductor-electrolyte and metal-electrolyte interfaces are discussed.

  2. Luminescent chiral ionic Ir(III) complexes: Synthesis and photophysical properties

    Energy Technology Data Exchange (ETDEWEB)

    Ricciardi, Loredana, E-mail: loredana.ricciardi@unical.it [CNR NANOTEC-Istituto di Nanotecnologia U.O.S. Cosenza, 87036 Arcavacata di Rende (CS) (Italy); La Deda, Massimo; Ionescu, Andreea; Godbert, Nicolas; Aiello, Iolinda; Ghedini, Mauro [MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), LASCAMM and CR INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, 87036 Arcavacata di Rende (CS) (Italy); Fusè, Marco, E-mail: marco.fuse@unimi.it [Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Golgi 19, 20133 Milano (Italy); Rimoldi, Isabella; Cesarotti, Edoardo [Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Golgi 19, 20133 Milano (Italy)

    2016-02-15

    Three homologous series of luminescent octahedral ionic Ir(III) complexes (1–12) with a dual stereogenic center of general formula {sup Δ,Λ} {sup (R,S)}[(ppy){sub 2}Ir(R-campy)]X, where ppy=2-phenylpyridine, R-campy=2-methyl-5,6,7,8-tetrahydroquinolin-8-amine (Me-campy) or 8-amino-5,6,7,8-tetrahydroquinolines (H-campy) and as counterions X{sup −}=Cl{sup −} or CH{sub 3}COO{sup −} have been synthesized and characterized. The NMR characterization of each complex highlighted the diastereoisomeric purity and the absolute configuration has been confirmed by Electronic Circular Dichroism spectroscopy. The absorption and the luminescence properties of the compounds in solution and in solid state have been investigated by UV–vis, steady-state emission and time-correlated single-photon counting spectroscopy. The obtained results from the 12 compounds highlight the difficult to correlate photophysical properties in solution to the stereochemistry, while excited states decay studies of the solid state samples indicate a correlation between photophysics and packing mode which is affected by the different stereochemistry. - Highlights: • Luminescent chiral ionic Ir(III) complexes have been synthesized and characterized. • Presence in the same structure of two stereogenic centers. • Use of camphorsulfonate as resolving anion to obtain enantiomerically pure samples. • Stereoisomers produce aggregates with different emitting properties. • Lifetimes from solid samples show the presence of AIPE.

  3. Selective recognition of palladium based on functional mono phthalocyanines; synthesis, characterization and photophysical properties

    Energy Technology Data Exchange (ETDEWEB)

    Yaraşir, M. Nilüfer; Aytekin, Ahmet [Department of Chemistry, Sakarya University, TR54187 Serdivan, Sakarya (Turkey); Kandaz, Mehmet, E-mail: mkandaz@sakarya.edu.tr [Department of Chemistry, Sakarya University, TR54187 Serdivan, Sakarya (Turkey); Güney, Orhan [Istanbul Technical University, Department of Chemistry, 34469 Maslak, Istanbul (Turkey)

    2016-09-15

    We report the synthesis and photophysical properties of 4,5-bis(2-((Z)-(3-hydroxynaphthalen-2-yl) methyleneamino)phenylthio)phthalonitrile ligand (SB) and its star-type functional zincphthalocyanine (SB-ZnPc) compound obtained by the condensation of 2,3,9,10,16,17,23,24-octakis-(2-aminophenylthio)zincphthlocyanines (A-ZnPc) and 1-hydroxy-2-naphthaldehyde (HNA). Each compound was purified and characterized by elemental analysis, FTIR, {sup 1}H NMR, {sup 13}C NMR, UV/vis and MS (Maldi-TOF) spectral data. SB-ZnPc bearing fluorescent SB moieties on the periphery shows selective palladium ion sensing behavior by acting as hard core upon interaction. Electronic spectra of the SB-ZnPc displays pronounced changes in both absorption and fluorescence spectra upon interaction with Pd{sup 2+} ion. The fluorescence of the SB-ZnPc compound is effectively quenched by treatment with Pd{sup 2+} in THF solution. The solvent effect on the photophysical properties of the SB-ZnPc and interference effect of foreign metal ions were also investigated.

  4. Photophysical and photobiological properties of a sulfonated chlorin photosensitiser TPCS(2a) for photochemical internalisation (PCI).

    Science.gov (United States)

    Wang, Julie T-W; Berg, Kristian; Høgset, Anders; Bown, Stephen G; MacRobert, Alexander J

    2013-03-01

    This study investigated the photophysical and photobiological properties of a new amphiphilic chlorin photosensitiser, disulfonated tetraphenylchlorin (TPCS(2a)), for photochemical internalisation (PCI). The absorption and fluorescence spectra of TPCS(2a) were examined in a range of solvents together with fluorescence lifetime measurements. The fluorescence lifetime of TPCS(2a) was found to be 8.5 ns in methanol, whereas non-exponential decays were observed in distilled water due to sensitiser dimerisation. The singlet oxygen quantum yield of TPCS(2a) was determined as 0.62 in deuterated methanol by direct observation of singlet oxygen phosphorescence. In a human oral squamous carcinoma (HN5) cell line, intracellular co-localisation of TPCS(2a) and Alexa488-labelled saporin, a macromolecular toxin, was observed corresponding predominantly to a lysosomal distribution. Intracellular fluorescence redistribution of TPCS(2a) and Alexa488-saporin was observed after 405 nm irradiation. Using two-photon confocal microscopy at 840 nm, and fluorescence lifetime imaging (FLIM), the lifetime was measured as 6 ns in HN5 cells. PCI using TPCS(2a) was shown to be very effective, and a synergistic increase in saporin toxicity was achieved in HN5 cells where viability was significantly reduced after light exposure compared to saporin (25 nM) treatment alone. The results demonstrate the favourable photophysical and photobiological properties of TPCS(2a) for PCI, which induces the relocalisation of a macromolecular anti-cancer toxin inside cells and significantly enhances cell death.

  5. Effect of diblock copolymer properties on the photophysical properties of dendrimer silicon phthalocyanine nanoconjugates

    Science.gov (United States)

    Chen, Kuizhi; Pan, Sujuan; Zhuang, Xuemei; Lv, Hafei; Que, Shoulin; Xie, Shusen; Yang, Hongqin; Peng, Yiru

    2016-07-01

    1-2 generation poly(benzyl aryl ether) dendrimer silicon phthalocyanines with axially disubstituted cyano terminal functionalities (G n -DSiPc(CN)4 n , (G n = n-generation dendrimer, n = 1-2)) were synthesized. Their structures were characterized by elemental analysis, IR, 1H NMR, and ESI-MS. Polymeric nanoparticles (G n -DSiPc(CN)4 n /m) were formed through encapsulating G n -DSiPc(CN)4 n into three monomethoxyl poly(ethylene glycol)-poly(ɛ-caprolactone) diblock copolymers (MPEG-PCL) with different hydrophilic/hydrophobic proportion, respectively. The effect of dendritic generation and the hydrophilic/hydrophobic proportion of diblock copolymers on the UV/Vis and fluorescence spectra of G n -DSiPc(CN)4 n and G n -DSiPc(CN)4 n /m were studied. The photophysical properties of polymeric nanoparticles exhibited dendritic generation and hydrophilic/hydrophobic proportion dependence. The fluorescence intensities and lifetimes of G n -DSiPc(CN)4 n /m were lower than the corresponding free dendrimer phthalocyanines. G n -DSiPc(CN)4 n encapsulated into MPEG-PCL with hydrophilic/hydrophobic molecular weight ratio 2000:4000 exhibited excellent photophysical property. The mean diameter of MPEG2000-PCL2000 micelles was about 70 nm, which decreased when loaded with G n -DSiPc(CN)4 n .

  6. Photophysical study of a charge transfer oxazole dye in micelles: Role of surfactant headgroups

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Jyotirmay [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India); Sarkar, Yeasmin; Parui, Partha Pratim [Department of Chemistry, Jadavpur University, Kolkata 700032 (India); Chakraborty, Sandipan [Department of Microbiology, University of Calcutta, Kolkata 700019 (India); Biswas, Suman [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India); Das, Ranjan, E-mail: ranjan.das68@gmail.com [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India)

    2015-07-15

    Photophysics of 5-(4′′-dimethylaminophenyl)-2-(4′-sulfophenyl)oxazole, sodium salt (DMO) which undergoes intramolecular charge transfer in the excited state was studied in micelles. In the cationic and the nonionic micelles, significantly higher fluorescence quantum yield is observed in comparison to the anionic micelles, due to much lower accessibility of DMO to the water molecules in the former micelles than the latter. Time-resolved fluorescence decays were characterized by a fast (τ{sub 1}) and a slow (τ{sub 2}) component of decay in all the micelles. The fast decay component (τ{sub 1}) increases significantly in going from the anionic micelles to the cationic micelles, because of the poorly hydrated headgroup region of the latter micelles compared to the former. Furthermore, much higher value of the slow component of decay (τ{sub 2}) is observed for the cationic and the neutral micelles than the anionic micelles. This is attributed to the increased penetration of water molecules into the micellar core of the anionic micelles compared to the cationic and the neutral micelles. - Highlights: • Photophysics of the fluorophore are remarkably different in the cationic and the anionic micelles. • Differential hydration of the surfactant headgroups gives rise to significantly different fluorescence quantum yield and lifetime in oppositely charged micelles. • Electrostatic interactions fine tune location of the fluorophore in the micelle–water interface of ionic micelles.

  7. Physical and photophysical properties of mixed double- and triple-decker sandwiches of porphyrins and phthalocyanines

    International Nuclear Information System (INIS)

    Salabert, Isabelle

    1995-01-01

    The study of electron transfer and charge recombination processes in various oligomers of porphyrins and phthalocyanines is reported. Our objective is to determine the nature of processes which compete with electron transfer in such Systems. The first part of this thesis is devoted to the study of mixed double- and triple-decker sandwich compounds of porphyrins and phthalocyanines of cerium and praseodymium. The charge transfer reaction and geminated recombination from excited complexes in solution and in sublimated film are investigated by time-resolved absorption spectroscopy with femtosecond time scale resolution. These results show the influence of the magnetic nature of the metal ion and of the relative position of the chromophores in the complex on the photophysical processes. The physical and photophysical properties of complexes formed by pairing in solution porphyrins and porphyrazines bearing oppositely charged substituent are reported in the second part. The formation of mixed aggregates of high order (2 to 5) is observed and their nature are spectrally characterized. The photoproducts issued from these complexes are extremely stable. (author) [fr

  8. Photophysics of the variable quantum yield of asymmetric bilirubin

    International Nuclear Information System (INIS)

    Troup, G.J.

    1998-01-01

    Full text: Bilirubin (BR), responsible for neonatal jaundice, is a molecule containing two pyrromethenone chromophores conjoined by a 'saturated' carbon CH 2 group. Because this disease is cured by phototherapy, BR has been extensively studied by laser means. When the chromophores in each half of the molecule are identical, we have symmetrical BR (SBR); when they are not, we have asymmetric BR (ASBR). The quantum yield of the photoproducts in simple organic solution from SBR is not wavelength-dependent, while that from ASBR is. Because of the proximity of the two chromophores, both the SBR and ASBR systems are subject to Davidoff (dynamic electric dipole) splitting of the chromophore excited states. A quantum mechanical calculation shows that when the two (ASBR) chromophore states are not degenerate, the higher Davidoff state is preferentially occupied by the chromophore with the 'original' higher energy, and the lower Davidoff state by the chromophore of 'original' lower energy. This is just what is required for the quantum yield to vary with wavelength. If the variation of the quantum yield of ASBR in the presence of human serum albumen is approximated by a square-wave (narrow line approximation), the deduced ratio of the short wavelength photoproduct yield with the long wavelength one is in agreement with accepted values for the 'original' energy difference of the chromophores, and the Davidoff splitting parameter. A previous explanation has involved variation of relaxation processes with wavelength, but only qualitatively. The quantum yields for SBRs bonded to HSA are not yet published, but show wavelength variation, possibly from asymmetric bonding. In 0.1% ammonia/methanol however, there is no such variation for the SBRs, while for ASBR, there is, and the photoproduct ratios for long and short wavelength are reciprocals of one another, as predicted by our theory

  9. Photophysical characterization and time-resolved spectroscopy of a anthradithiophene dimer: exploring the role of conformation in singlet fission

    KAUST Repository

    Dean, Jacob C.

    2017-08-18

    Quantitative singlet fission has been observed for a variety of acene derivatives such as tetracene and pentacene, and efforts to extend the library of singlet fission compounds is of current interest. Preliminary calculations suggest anthradithiophenes exhibit significant exothermicity between the first optically-allowed singlet state, S1, and 2 × T1 with an energy difference of >5000 cm−1. Given the fulfillment of this ingredient for singlet fission, here we investigate the singlet fission capability of a difluorinated anthradithiophene dimer (2ADT) covalently linked by a (dimethylsilyl)ethane bridge and derivatized by triisobutylsilylethynyl (TIBS) groups. Photophysical characterization of 2ADT and the single functionalized ADT monomer were carried out in toluene and acetone solution via absorption and fluorescence spectroscopy, and their photo-initiated dynamics were investigated with time-resolved fluorescence (TRF) and transient absorption (TA) spectroscopy. In accordance with computational predictions, two conformers of 2ADT were observed via fluorescence spectroscopy and were assigned to structures with the ADT cores trans or cis to one another about the covalent bridge. The two conformers exhibited markedly different excited state deactivation mechanisms, with the minor trans population being representative of the ADT monomer showing primarily radiative decay, while the dominant cis population underwent relaxation into an excimer geometry before internally converting to the ground state. The excimer formation kinetics were found to be solvent dependent, yielding time constants of ∼1.75 ns in toluene, and ∼600 ps in acetone. While the difference in rates elicits a role for the solvent in stabilizing the excimer structure, the rate is still decidedly long compared to most singlet fission rates of analogous dimers, suggesting that the excimer is neither a kinetic nor a thermodynamic trap, yet singlet fission was still not observed. The result

  10. Determination of functions of controlling drives of main executive mechanisms of mining excavators

    Science.gov (United States)

    Lagunova, Yu A.; Komissarov, A. P.; Lukashuk, O. A.

    2018-03-01

    It is shown that a special shovel is a feature of the structure of the drives of the main mechanisms (mechanisms of lifting and pressure) of career excavators with working equipment, the presence in the transfer device of a two-crank-lever mechanism of working equipment that connects the main mechanisms with the working body (bucket). In this case, the transformation of the mechanical energy parameters of the motors into energy-force parameters realized at the cutting edge of the bucket (teeth) takes place depending on the type of the kinematic scheme of the two-link-lever mechanism. The concept of “control function” defining the relationship between the parameters characterizing the position of the bucket in the face (the coordinates of the tip of the cutting edge of the bucket, the digging speed) and the required control level are introduced. These are the values of the lifting and head speeds ensuring the bucket movement along a given trajectory.

  11. A Modified Model Reference Adaptive Control for a Single Motor of Latch Type Control Element Drive Mechanism

    International Nuclear Information System (INIS)

    Park, Bae Jeong

    2016-01-01

    A modified Model Reference Adaptive Control (MRAC) for a single motor of latch type Control Element Drive Mechanism (CEDM) is described herein. The CEDM has complicated dynamic characteristics including electrical, mechanical, and magnetic effects. The previous control system has utilized a Proportional-Integral (PI) controller, and the control performance is limited according to nonlinear dynamic characteristics and environmental conditions. The modified MRAC using system identification (ID) technique improves the control performance in the operating condition such as model parameter variation and environmental condition change. The modified MRAC using the identified reference model with feed-forward gain and 180Hz noise reduction filter presents better performance under normal and/or abnormal condition. The simplified reference model can make H/W implementation more practical on the viewpoint of less computation and good performance. Actually, the CEDM controller shall be capable of controlling 101 control element assemblies (CEAs) individually in the nuclear power plant. Because the load conditions and the environmental condition around the 101 CEAs are all different minutely, the proposed modified MRAC can be a good practice. The modified MRAC controller will be applied in the real nuclear power plant later and this will overcome some weak point of PI controller

  12. Singlet exciton fission in polycrystalline pentacene: from photophysics toward devices.

    Science.gov (United States)

    Wilson, Mark W B; Rao, Akshay; Ehrler, Bruno; Friend, Richard H

    2013-06-18

    generated via singlet fission in pentacene can be dissociated at an interface with a suitable electron acceptor, such as fullerenes and infrared-absorbing inorganic semiconducting quantum dots. We highlight our recent reports of a pentacene/PbSe hybrid solar cell with a power conversion efficiency of 4.7% and of a pentacene/PbSe/amorphous silicon photovoltaic device. Although substantive challenges remain, both to better our understanding of the mechanism of singlet exciton fission and to optimize device performance, this realization of a solar cell where photocurrent is simultaneously contributed from a blue-absorbing fission-capable material and an infrared-absorbing conventional cell is an important step towards a dual-bandgap, single-junction, fission-enhanced photovoltaic device, which could one day surpass the Shockley-Queisser limit.

  13. Advanced optical measurements for characterizing photophysical properties of single nanoparticles.

    Energy Technology Data Exchange (ETDEWEB)

    Polsky, Ronen; Davis, Ryan W.; Arango, Dulce C.; Brozik, Susan Marie; Wheeler, David Roger

    2009-09-01

    Formation of complex nanomaterials would ideally involve single-pot reaction conditions with one reactive site per nanoparticle, resulting in a high yield of incrementally modified or oriented structures. Many studies in nanoparticle functionalization have sought to generate highly uniform nanoparticles with tailorable surface chemistry necessary to produce such conjugates, with limited success. In order to overcome these limitations, we have modified commercially available nanoparticles with multiple potential reaction sites for conjugation with single ssDNAs, proteins, and small unilamellar vesicles. These approaches combined heterobifunctional and biochemical template chemistries with single molecule optical methods for improved control of nanomaterial functionalization. Several interesting analytical results have been achieved by leveraging techniques unique to SNL, and provide multiple paths for future improvements for multiplex nanoparticle synthesis and characterization. Hyperspectral imaging has proven especially useful for assaying substrate immobilized fluorescent particles. In dynamic environments, temporal correlation spectroscopies have been employed for tracking changes in diffusion/hydrodynamic radii, particle size distributions, and identifying mobile versus immobile sample fractions at unbounded dilution. Finally, Raman fingerprinting of biological conjugates has been enabled by resonant signal enhancement provided by intimate interactions with nanoparticles and composite nanoshells.

  14. Pitch control for ships with diesel mechanical and hybrid propulsion : Modelling, validation and performance quantification

    NARCIS (Netherlands)

    Geertsma, R.D.; Negenborn, R.R.; Visser, K.; Loonstijn, M.A.; Hopman, J.J.

    2017-01-01

    Ships, in particular service vessels, need to reduce fuel consumption, emissions and cavitation noise while maintaining manoeuvrability and preventing engine overloading. Diesel mechanical propulsion with controllable pitch propellers can provide high fuel efficiency with good manoeuvrability.

  15. State of the Art Report for Development of Control Element Drive Mechanism of the APR+ Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Seon; Choi, Suhn; Song, Chul Hwa

    2008-10-15

    Recently newly-developed nuclear reactors with increased safety and enhanced performance by developed countries in the nuclear area are competing in the global nuclear market. Several reactors, for example AP600 and AP1000 by Westinghouse Electric Co. in USA, EPR by Areva in Europe, APWR by Mitsubishi Heavy Industry in Japan in the pressurized power reactor, are competing to preoccupy the nuclear market during Nuclear Renaissance. Dedicated control element drive mechanism with enhanced performance and increased safety are developed for these new reactors. And load follow capability is required, and it is estimated that load follow requirement make design requirement of a control element drive mechanism harsh. It is necessary to review the current technical state of a control element drive mechanism. This work is aimed to review the design characteristics of a past and current control element drive mechanism for a nuclear reactor and to check the direction and goal of CEDM design development recently.

  16. State of the Art Report for Development of Control Element Drive Mechanism of the APR+ Reactor

    International Nuclear Information System (INIS)

    Lee, Jae Seon; Choi, Suhn; Song, Chul Hwa

    2008-10-01

    Recently newly-developed nuclear reactors with increased safety and enhanced performance by developed countries in the nuclear area are competing in the global nuclear market. Several reactors, for example AP600 and AP1000 by Westinghouse Electric Co. in USA, EPR by Areva in Europe, APWR by Mitsubishi Heavy Industry in Japan in the pressurized power reactor, are competing to preoccupy the nuclear market during Nuclear Renaissance. Dedicated control element drive mechanism with enhanced performance and increased safety are developed for these new reactors. And load follow capability is required, and it is estimated that load follow requirement make design requirement of a control element drive mechanism harsh. It is necessary to review the current technical state of a control element drive mechanism. This work is aimed to review the design characteristics of a past and current control element drive mechanism for a nuclear reactor and to check the direction and goal of CEDM design development recently

  17. Nonlinear Lyapunov-based boundary control of distributed heat transfer mechanisms in membrane distillation plant

    KAUST Repository

    Eleiwi, Fadi; Laleg-Kirati, Taous-Meriem

    2015-01-01

    This paper presents a nonlinear Lyapunov-based boundary control for the temperature difference of a membrane distillation boundary layers. The heat transfer mechanisms inside the process are modeled with a 2D advection-diffusion equation. The model

  18. CONTROLLING AS A MECHANISM TO INCREASE THE EFFICIENCY OF MANAGEMENT ENTERPRISES OF FUEL-ENERGY COMPLEX

    Directory of Open Access Journals (Sweden)

    M. A. Ostashkin

    2013-01-01

    Full Text Available This article discusses the possibility of application of controlling as mechanism of increasing the efficiency of management of enterprises of fuel- energy complex. The research was conducted on the materials of the JSC «Gazprom».

  19. Efficacy and mechanisms of non-antibacterial, chemical plaque control by dentifrices - An in vitro study

    NARCIS (Netherlands)

    Busscher, Henk J.; White, Don J.; Atema-Smit, Jelly; van der Mei, Henny C.

    Objectives: The provision of antiplaque benefits to dentifrices assists patients in improving hygiene and reducing susceptibility to gingivitis and caries. Chemical plaque control involves different mechanisms and is mostly associated with antibacterial effects, but also includes effects on pellicle

  20. A methodology for identification and control of electro-mechanical actuators.

    Science.gov (United States)

    Tutunji, Tarek A; Saleem, Ashraf

    2015-01-01

    Mechatronic systems are fully-integrated engineering systems that are composed of mechanical, electronic, and computer control sub-systems. These integrated systems use electro-mechanical actuators to cause the required motion. Therefore, the design of appropriate controllers for these actuators are an essential step in mechatronic system design. In this paper, a three-stage methodology for real-time identification and control of electro-mechanical actuator plants is presented, tested, and validated. First, identification models are constructed from experimental data to approximate the plants' response. Second, the identified model is used in a simulation environment for the purpose of designing a suitable controller. Finally, the designed controller is applied and tested on the real plant through Hardware-in-the-Loop (HIL) environment. The described three-stage methodology provides the following practical contributions: •Establishes an easy-to-follow methodology for controller design of electro-mechanical actuators.•Combines off-line and on-line controller design for practical performance.•Modifies the HIL concept by using physical plants with computer control (rather than virtual plants with physical controllers). Simulated and experimental results for two case studies, induction motor and vehicle drive system, are presented in order to validate the proposed methodology. These results showed that electromechanical actuators can be identified and controlled using an easy-to-duplicate and flexible procedure.

  1. Experimental and numerical investigation of a phase-only control mechanism in the linear intensity regime.

    Science.gov (United States)

    Brühl, Elisabeth; Buckup, Tiago; Motzkus, Marcus

    2018-06-07

    Mechanisms and optimal experimental conditions in coherent control still intensely stimulate debates. In this work, a phase-only control mechanism in an open quantum system is investigated experimentally and numerically. Several parameterizations for femtosecond pulse shaping (combination of chirp and multipulses) are exploited in transient absorption of a prototype organic molecule to control population and vibrational coherence in ground and excited states. Experimental results are further numerically simulated and corroborated with a four-level density-matrix model, which reveals a phase-only control mechanism based on the interaction between the tailored phase of the excitation pulse and the induced transient absorption. In spite of performing experiment and numerical simulations in the linear regime of excitation, the control effect amplitude depends non-linearly on the excitation energy and is explained as a pump-dump control mechanism. No evidence of single-photon control is observed with the model. Moreover, our results also show that the control effect on the population and vibrational coherence is highly dependent on the spectral detuning of the excitation spectrum. Contrary to the popular belief in coherent control experiments, spectrally resonant tailored excitation will lead to the control of the excited state only for very specific conditions.

  2. Spectroscopy and photophysics of self-organized zinc porphyrin nanolayers. 1. Optical spectroscopy of excitonic interactions involving the soret band

    NARCIS (Netherlands)

    Donker, H.; Koehorst, R.B.M.; Schaafsma, T.J.

    2005-01-01

    The photophysical properties of excited singlet states of zinc tetra-(p-octylphenyl)-porphyrin in 5-25-nm-thick films spin-coated onto quartz slides have been investigated by optical spectroscopy. Analysis of the polarized absorption spectra using a dipole-dipole exciton model with two mutually

  3. Comparing the photophysics of the two forms of the Orange Carotenoid Protein using 2D electronic spectroscopy

    Directory of Open Access Journals (Sweden)

    Mathies R.A.

    2013-03-01

    Full Text Available Broadband two-dimensional electronic spectroscopy is applied to investigate the photophysics of the photoactive orange carotenoid protein, which is involved in nonphotochemical quenching in cyanobacteria. Differences in dynamics between the light and dark forms arise from the different structure of the carotenoid in the protein pocket, with consequences for the biological role of the two forms.

  4. Computer-controlled mechanical lung model for application in pulmonary function studies

    NARCIS (Netherlands)

    A.F.M. Verbraak (Anton); J.E.W. Beneken; J.M. Bogaard (Jan); A. Versprille (Adrian)

    1995-01-01

    textabstractA computer controlled mechanical lung model has been developed for testing lung function equipment, validation of computer programs and simulation of impaired pulmonary mechanics. The construction, function and some applications are described. The physical model is constructed from two

  5. Identifying mechanisms in the control of quantum dynamics through Hamiltonian encoding

    International Nuclear Information System (INIS)

    Mitra, Abhra; Rabitz, Herschel

    2003-01-01

    A variety of means are now available to design control fields for manipulating the evolution of quantum systems. However, the underlying physical mechanisms often remain obscure, especially in the cases of strong fields and high quantum state congestion. This paper proposes a method to quantitatively determine the various pathways taken by a quantum system in going from the initial state to the final target. The mechanism is revealed by encoding a signal in the system Hamiltonian and decoding the resultant nonlinear distortion of the signal in the system time-evolution operator. The relevant interfering pathways determined by this analysis give insight into the physical mechanisms operative during the evolution of the quantum system. A hierarchy of mechanism identification algorithms with increasing ability to extract more detailed pathway information is presented. The mechanism identification concept is presented in the context of analyzing computer simulations of controlled dynamics. As illustrations of the concept, mechanisms are identified in the control of several simple, discrete-state quantum systems. The mechanism analysis tools reveal the roles of multiple interacting quantum pathways to maximally take advantage of constructive and destructive interference. Similar procedures may be applied directly in the laboratory to identify control mechanisms without resort to computer modeling, although this extension is not addressed in this paper

  6. Mechanical tests of the bolt of the gripper latch on the control rod cluster

    International Nuclear Information System (INIS)

    Lemaire, E.; Couet, D.; Molinie, D.; Grandjean, Y.; Radat, M.P.; Guttmann, D.

    1998-01-01

    Failure analysis and mechanical testing indicate that control rod drive mechanisms malfunctioning by 1995-96 is due to rupture by fatigue of a bolt inside the stationary gripper assembly. Fatigue is enhanced by free working following surface adaptation and unscrewing of the assembly. These results are taken into account for the choice of a new anti-rotation device. (authors)

  7. Study on the control mechanism of China aerospace enterprises' binary multinational operation

    Institute of Scientific and Technical Information of China (English)

    Wang Jian; Li Hanling; Wu Weiwei

    2008-01-01

    China's aerospace enterprises carry on the multinational operation and participate in the international competition and the international division of labor and cooperation positively.This article first analyzs China aerospace enterprises' binary multinational business control objective and constructes its model.Then the article analyzes the tangible and intangible control mechanism of China aerospace enterprises' binary multinational operation respectively.Finally,the article constructs the model of China aerospace enterprises' binary multinational operation mechanisms.

  8. Design and Development of Mechanical Structure and Control System for Tracked Trailing Mobile Robot

    OpenAIRE

    Hongchuan Xu; Jianxing Ren; Rui Zhu; Zhiwei Chen

    2013-01-01

    Along with the science and technology unceasing progress, the uses of tracing robots become more and more widely. Tracked tracing robot was adopted as the research object in this paper, mechanical structure and control system of robot was designed and developmented. In mechanical structure design part, structure designed and positioned  were completed, including design of robot body, wheel, underpan, transmission structure and the positioning of batteries, control panel, sensors, etc, and the...

  9. Global chaos synchronization of electro-mechanical gyrostat systems via variable substitution control

    International Nuclear Information System (INIS)

    Chen Yun; Wu Xiaofeng; Liu Zhong

    2009-01-01

    This paper studies global synchronization of non-autonomous chaotic electro-mechanical gyrostat systems via variable substitution control. A master-slave non-autonomous synchronization scheme with variable substitution control is mathematically presented. Based on the scheme, some sufficient algebraic criteria for global chaos synchronization of master and slave electro-mechanical gyrostat systems via various single-variable coupling are derived. The effectiveness of the obtained criteria is numerically illustrated by the examples.

  10. Numerical simulation of volume-controlled mechanical ventilated respiratory system with 2 different lungs.

    Science.gov (United States)

    Shi, Yan; Zhang, Bolun; Cai, Maolin; Zhang, Xiaohua Douglas

    2017-09-01

    Mechanical ventilation is a key therapy for patients who cannot breathe adequately by themselves, and dynamics of mechanical ventilation system is of great significance for life support of patients. Recently, models of mechanical ventilated respiratory system with 1 lung are used to simulate the respiratory system of patients. However, humans have 2 lungs. When the respiratory characteristics of 2 lungs are different, a single-lung model cannot reflect real respiratory system. In this paper, to illustrate dynamic characteristics of mechanical ventilated respiratory system with 2 different lungs, we propose a mathematical model of mechanical ventilated respiratory system with 2 different lungs and conduct experiments to verify the model. Furthermore, we study the dynamics of mechanical ventilated respiratory system with 2 different lungs. This research study can be used for improving the efficiency and safety of volume-controlled mechanical ventilation system. Copyright © 2016 John Wiley & Sons, Ltd.

  11. The Dynamic Evolution of Firms’ Pollution Control Strategy under Graded Reward-Penalty Mechanism

    Directory of Open Access Journals (Sweden)

    Li Ming Chen

    2016-01-01

    Full Text Available The externality of pollution problem makes firms lack enough incentive to reduce pollution emission. Therefore, it is necessary to design a reasonable environmental regulation mechanism so as to effectively urge firms to control pollution. In order to inspire firms to control pollution, we divide firms into different grades according to their pollution level and construct an evolutionary game model to analyze the interaction between government’s regulation and firms’ pollution control under graded reward-penalty mechanism. Then, we discuss stability of firms’ pollution control strategy and derive the condition of inspiring firms to control pollution. Our findings indicate that firms tend to control pollution after long-term repeated games if government’s excitation level and monitoring frequency meet some conditions. Otherwise, firms tend to discharge pollution that exceeds the stipulated standards. As a result, in order to effectively control pollution, a government should adjust its excitation level and monitoring frequency reasonably.

  12. Mechanization of and experience with a triplex fly-by-wire backup control system

    Science.gov (United States)

    Lock, W. P.; Petersen, W. R.; Whitman, G. B.

    1976-01-01

    A redundant three axis analog control system was designed and developed to back up a digital fly by wire control system for an F-8C airplane. The mechanization and operational experience with the backup control system, the problems involved in synchronizing it with the primary system, and the reliability of the system are discussed. The backup control system was dissimilar to the primary system, and it provided satisfactory handling through the flight envelope evaluated. Limited flight tests of a variety of control tasks showed that control was also satisfactory when the backup control system was controlled by a minimum displacement (force) side stick. The operational reliability of the F-8 digital fly by wire control system was satisfactory, with no unintentional downmodes to the backup control system in flight. The ground and flight reliability of the system's components is discussed.

  13. Controlled switching of single-molecule junctions by mechanical motion of a phenyl ring

    Directory of Open Access Journals (Sweden)

    Yuya Kitaguchi

    2015-10-01

    Full Text Available Mechanical methods for single-molecule control have potential for wide application in nanodevices and machines. Here we demonstrate the operation of a single-molecule switch made functional by the motion of a phenyl ring, analogous to the lever in a conventional toggle switch. The switch can be actuated by dual triggers, either by a voltage pulse or by displacement of the electrode, and electronic manipulation of the ring by chemical substitution enables rational control of the on-state conductance. Owing to its simple mechanics, structural robustness, and chemical accessibility, we propose that phenyl rings are promising components in mechanical molecular devices.

  14. MTPA control of mechanical sensorless IPMSM based on adaptive nonlinear control.

    Science.gov (United States)

    Najjar-Khodabakhsh, Abbas; Soltani, Jafar

    2016-03-01

    In this paper, an adaptive nonlinear control scheme has been proposed for implementing maximum torque per ampere (MTPA) control strategy corresponding to interior permanent magnet synchronous motor (IPMSM) drive. This control scheme is developed in the rotor d-q axis reference frame using adaptive input-output state feedback linearization (AIOFL) method. The drive system control stability is supported by Lyapunov theory. The motor inductances are online estimated by an estimation law obtained by AIOFL. The estimation errors of these parameters are proved to be asymptotically converged to zero. Based on minimizing the motor current amplitude, the MTPA control strategy is performed by using the nonlinear optimization technique while considering the online reference torque. The motor reference torque is generated by a conventional rotor speed PI controller. By performing MTPA control strategy, the generated online motor d-q reference currents were used in AIOFL controller to obtain the SV-PWM reference voltages and the online estimation of the motor d-q inductances. In addition, the stator resistance is online estimated using a conventional PI controller. Moreover, the rotor position is detected using the online estimation of the stator flux and online estimation of the motor q-axis inductance. Simulation and experimental results obtained prove the effectiveness and the capability of the proposed control method. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Plant management in natural areas: balancing chemical, mechanical, and cultural control methods

    Science.gov (United States)

    Steven Manning; James. Miller

    2011-01-01

    After determining the best course of action for control of an invasive plant population, it is important to understand the variety of methods available to the integrated pest management professional. A variety of methods are now widely used in managing invasive plants in natural areas, including chemical, mechanical, and cultural control methods. Once the preferred...

  16. Engine Performance (Section C: Emission Control Systems). Auto Mechanics Curriculum Guide. Module 3. Instructor's Guide.

    Science.gov (United States)

    Rains, Larry

    This engine performance (emission control systems) module is one of a series of competency-based modules in the Missouri Auto Mechanics Curriculum Guide. Topics of this module's five units are: positive crankcase ventilation (PCV) and evaporative emission control systems; exhaust gas recirculation (EGR); air injection and catalytic converters;…

  17. Engine Tune-up Service. Unit 6: Emission Control Systems. Student Guide. Automotive Mechanics Curriculum.

    Science.gov (United States)

    Bacon, E. Miles

    This student guide is for Unit 6, Emission Control Systems, in the Engine Tune-Up Service portion of the Automotive Mechanics Curriculum. It deals with inspecting, testing, and servicing an emission control system. A companion review exercise book and posttests are available separately as CE 031 221-222. An introduction tells how this unit fits…

  18. Robust control of distributed parameter mechanical systems using a multidimensional systems approach

    Czech Academy of Sciences Publication Activity Database

    Cichy, B.; Augusta, Petr; Rogers, E.; Galkowski, K.; Hurák, Z.

    2010-01-01

    Roč. 58, č. 1 (2010), s. 67-75 ISSN 0239-7269 R&D Projects: GA MŠk(CZ) 1M0567 Institutional research plan: CEZ:AV0Z10750506 Keywords : robust control * distributed parameter mechanical systems * multidimensional systems Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/2010/TR/augusta-0347866.pdf

  19. Different Rols of Modified Organoclay in Deformation Mechanism Control of Polymeric Matrices

    Directory of Open Access Journals (Sweden)

    Babak Akbari

    2014-04-01

    Full Text Available The effect of organically modified clay on the structure and deformation mechanism of polymeric matrices was investigated. For this purpose, the role of organoclay in deformation control of polymeric matrices, with different deformation mechanisms, has been studied methodically in order to determine a relationship between the structure and deformation mechanisms. In this respect polypropylene and polystyrene composites systems were designed using montmorillonite through melt intercalation technique using a twin, co-rotating extruder with starve feeding system. Also an epoxy was employed to design a nanocomposite system prepared by in-situ polymerization technique. The structure and deformation mechanism of nanocomposites were investigated using appropriate techniques. X-Ray diffraction and transmission electron microscopy were used to explore the structure of various systems while, the reflection and transmission optical microscopy were used in order to study their corresponding deformation mechanisms. The bulk polymer was also studied for its deformation mechanism by reflection optical microscopy and the notch tip of the samples were examined by transmission optical microscopy. The results of experiments showed that organoclays acted as initiator sites for shear yielding mechanism as the dominant deformation mechanism in epoxies. It may be noted that, these particles may act as initiator sites for crazing, the dominant deformation mechanism of polystyrene, and alter the mechanism from local to massive. In polypropylene systems, which may exhibit both shear yielding and crazing organoclays can facilitate or postpone both mechanisms in different conditions, related to PP morphology and other conditions.

  20. Microcontroller Based Proportional Derivative Plus Conditional Integral Controller for Electro-Mechanical Dual Acting Pulley Continuously Variable Transmission Ratio Control

    International Nuclear Information System (INIS)

    Budianto, A; Tawi, K B; Hussein, M; Supriyo, B; Kob, M S Che; Zulkifli, Mohd Ezlamy; Khairuldean A K; Daraoh, Aishah; Ariyono, S

    2012-01-01

    Electro-Mechanical Dual Acting Pulley (EMDAP) Continuously Variable Transmission (CVT) is a transmission utilized by electro-mechanical actuated system. It has a potential to reduce energy consumption because it only needs power during changing CVT ratio and no power is needed to maintain CVT ratio due to self lock mechanism design. This paper proposed simple proportional derivative plus conditional integral (PDCI) controller to control EMDAP CVT ratio which can be simply implemented on a microcontroller. This proposed controller used Astrom-Hagglund method and Ziegler-Nichols formula to tune PDCI gain. The Proportional Derivative controller is directly activated from the start but Integral controller is only activated when the error value reaches error value setting point. Simulation using Matlab/Simulink software was conducted to evaluate PDCI system performance. The simulation results showed PDCI controller has ability to perform maximum overshoot 0.1%, 0.001 steady state error and 0.5s settling time. For clamping condition, settling time is about 11.46s during changing ratio from 2.0 to 0.7, while for release condition, settling time is about 8.33s during changing ratio from 0.7 to 2.0.

  1. Hydraulic actuator mechanism to control aircraft spoiler movements through dual input commands

    Science.gov (United States)

    Irick, S. C. (Inventor)

    1981-01-01

    An aircraft flight spoiler control mechanism is described. The invention enables the conventional, primary spoiler control system to retain its operational characteristics while accommodating a secondary input controlled by a conventional computer system to supplement the settings made by the primary input. This is achieved by interposing springs between the primary input and the spoiler control unit. The springs are selected to have a stiffness intermediate to the greater force applied by the primary control linkage and the lesser resistance offered by the spoiler control unit. Thus, operation of the primary input causes the control unit to yield before the springs, yet, operation of the secondary input, acting directly on the control unit, causes the springs to yield and absorb adjustments before they are transmitted into the primary control system.

  2. Analysis of controlled-mechanism of grain growth in undercooled Fe-Cu alloy

    International Nuclear Information System (INIS)

    Chen Zheng; Liu Feng; Yang Xiaoqin; Shen Chengjin; Fan Yu

    2011-01-01

    Highlights: → In terms of a thermo-kinetic model applicable for micro-scale undercooled Fe-4 at.% Cu alloy, grain growth behavior of the single-phase supersaturated granular grain was investigated. → In comparison of pure kinetic model, pure thermodynamic model and the extended thermo-kinetic model, two characteristic annealing time were determined. → The controlled-mechanism of grain growth in undercooled Fe-Cu alloy was proposed, including a mainly kinetic-controlled process, a transition from kinetic-mechanism to thermodynamic-mechanism and purely thermodynamic-controlled process. - Abstract: An analysis of controlled-mechanism of grain growth in the undercooled Fe-4 at.% Cu immiscible alloy was presented. Grain growth behavior of the single-phase supersaturated granular grains prepared in Fe-Cu immiscible alloy melt was investigated by performing isothermal annealings at 500-800 deg. C. The thermo-kinetic model [Chen et al., Acta Mater. 57 (2009) 1466] applicable for nano-scale materials was extended to the system of micro-scale undercooled Fe-4 at.% Cu alloy. In comparison of pure kinetic model, pure thermodynamic model and the extended thermo-kinetic model, two characteristic annealing time (t 1 and t 2 ) were determined. The controlled-mechanism of grain growth in undercooled Fe-Cu alloy was proposed, including a mainly kinetic-controlled process (t ≤ t 1 ), a transition from kinetic-mechanism to thermodynamic-mechanism (t 1 2 ) and purely thermodynamic-controlled process (t ≥ t 2 ).

  3. Pitch control for ships with diesel mechanical and hybrid propulsion: Modelling, validation and performance quantification

    OpenAIRE

    Geertsma, R.D.; Negenborn, R.R.; Visser, K.; Loonstijn, M.A.; Hopman, J.J.

    2017-01-01

    Ships, in particular service vessels, need to reduce fuel consumption, emissions and cavitation noise while maintaining manoeuvrability and preventing engine overloading. Diesel mechanical propulsion with controllable pitch propellers can provide high fuel efficiency with good manoeuvrability. However, the conventional control strategy with fixed combinator curves limits control freedom in trading-off performance characteristics. In order to evaluate performance of current state-of-the-art an...

  4. The Dynamic Evolution of Firms’ Pollution Control Strategy under Graded Reward-Penalty Mechanism

    OpenAIRE

    Li Ming Chen; Wen Ping Wang

    2016-01-01

    The externality of pollution problem makes firms lack enough incentive to reduce pollution emission. Therefore, it is necessary to design a reasonable environmental regulation mechanism so as to effectively urge firms to control pollution. In order to inspire firms to control pollution, we divide firms into different grades according to their pollution level and construct an evolutionary game model to analyze the interaction between government’s regulation and firms’ pollution control under g...

  5. Acoustic and Vibration Control for an Underwater Structure under Mechanical Excitation

    Directory of Open Access Journals (Sweden)

    Shi-Jian Zhu

    2014-01-01

    Full Text Available Acoustic and vibration control for an underwater structure under mechanical excitation has been investigated by using negative feedback control algorithm. The underwater structure is modeled with cylindrical shells, conical shells, and circular bulkheads, of which the motion equations are built with the variational approach, respectively. Acoustic property is analyzed by the Helmholtz integration formulation with boundary element method. Based on negative feedback control algorithm, a control loop with a coupling use of piezoelectric sensor and actuator is built, and accordingly some numerical examples are carried out on active control of structural vibration and acoustic response. Effects of geometrical and material parameters on acoustic and vibration properties are investigated and discussed.

  6. Information-theoretical approach to control of quantum-mechanical systems

    International Nuclear Information System (INIS)

    Kawabata, Shiro

    2003-01-01

    Fundamental limits on the controllability of quantum mechanical systems are discussed in the light of quantum information theory. It is shown that the amount of entropy-reduction that can be extracted from a quantum system by feedback controller is upper bounded by a sum of the decrease of entropy achievable in open-loop control and the mutual information between the quantum system and the controller. This upper bound sets a fundamental limit on the performance of any quantum controllers whose designs are based on the possibilities to attain low entropy states. An application of this approach pertaining to quantum error correction is also discussed

  7. Photophysics and lasing correlation of pyrromethene 567 dye in crosslinked polymeric networks

    International Nuclear Information System (INIS)

    Banuelos Prieto, J.; Lopez Arbeloa, F.; Garcia, O.; Arbeloa, I. Lopez

    2007-01-01

    The photophysical properties of the pyrromethene 567 dye incorporated in copolymers of methylmethacrylate with different acrylic and methacrylic crosslinking monomers are reported. In general, the solid matrices improve the fluorescence capacity of the dye, due to both an increase and a decrease in the radiative and non-radiative deactivation rate constants, respectively, as consequence of a more rigid environment. It is observed that there is an optimal crosslinking degree for the highest fluorescence efficiency, which depends on the nature of the crosslinking monomer. Taking into account the lasing properties for these systems, it is established a good correlation between the lasing and the fluorescence characteristics of the dye in agreement with previous conclusions obtained in liquid solutions

  8. Photophysical studies of oxicam group of NSAIDs: piroxicam, meloxicam and tenoxicam

    Science.gov (United States)

    Banerjee, Rona; Chakraborty, Hirak; Sarkar, Munna

    2003-04-01

    Oxicam group of non steroidal anti-inflammatory drugs has been chosen as a prototype molecular group that shows diverse biological functions and dynamic structural features. Photophysical studies of three drugs from this group viz., piroxicam, meloxicam and tenoxicam have been carried out in different solvents with varying polarity, H-bond character and viscosity. The spectral responses of different prototropic forms of these drugs towards varying solvent parameters have been studied, with the aim to characterize their interaction in biomimetic environment non-invasively. The nature of the lowest transition has been identified. The extinction coefficient, quantum yield and viscosity dependence on the nature of the solvents, all indicate the extreme sensitivity of these drugs to their microenvironment.

  9. Synthesis, Photophysics, Electrochemistry and Electrogenerated Chemiluminescence of a Homologous Set of BODIPY-Appended Bipyridine Derivatives.

    Science.gov (United States)

    Rosenthal, Joel; Nepomnyashchii, Alexander B; Kozhukh, Julia; Bard, Allen J; Lippard, Stephen J

    2011-09-15

    Two new 2,2'-bipyridine (bpy) based ligands with ancillary BODIPY chromophores attached at the 4 and 4'-positions were prepared and characterized, which vary in the substitution pattern about the BODIPY periphery by either excluding (BB1) or including (BB2) a β-alkyl substituent. Both absorb strongly throughout the visible region and are strongly emissive. The basic photophysics and electrochemical properties of BB1 and BB2 are comparable to those of the BODIPY monomers on which they are based. The solid-state structures and electronic structure calculations both indicate that there is negligible electronic communication between the BODIPY moieties and the intervening bpy spacers. Electrogenerated chemiluminescence spectra of the two Bpy-BODIPY derivatives are similar to their recorded fluorescence profiles and are strongly influenced by substituents on the BODIPY chromophores. These 2,2'-bipyridine derivatives represent a new set of ligands that should find utility in applications including light-harvesting, photocatalysis, and molecular electronics.

  10. Copolymers containing meta-pyridylvinylene and para-arylenevinylene fragments: synthesis, quaternization reaction, and photophysical properties

    Science.gov (United States)

    Barashkov, Nikolay N.; Olivos, Hernando J.; Ferraris, John P.

    1997-12-01

    We report the Wittig reaction of the diphosphonium salt of 2,6-bis(chloromethyl)pyridine with terephthaldehyde, 2.5- dioctyloxyterephthaldehyde, or 9,10-anthracenedicarbaldehyde to form conjugated copolymers with fragments of 2,6 - pyridylene and para-arylenevinylene. The protonation reaction of poly(para-arylenevinylene)-co-(meta- pyridylvinylene) with hydrochloric acid and the quaternization reaction of poly(2,5-dioctyloxy-1,4- phenylenevinylene)-co-(2,6-pyridylvinylene) with methyl triflate have been investigated by spectrophotometric and fluorescent methods. The absorption, excitation and fluorescence spectra of these copolymers as well as their corresponding model compounds were studied and compared. The photophysical properties of the investigated polymers suggest that these materials could be good candidates for the fabrication of efficient blue and green light-emitting diodes.

  11. Enhancing photophysical and photochemical properties of zinc(II) phthalocyanine dyes by substitution of triptycene moieties

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sohaimi, Bander Roshadan [Department of Chemistry, Faculty of Science, Taibah University, P.O. Box 344, Al-Madinah Al Munawwrah (Saudi Arabia); Pişkin, Mehmet [Çanakkale Onsekiz Mart University, Vocational School of Technical Sciences, Department of Food Technology, Çanakkale 17100 (Turkey); Aljuhani, Ateyatallah; Al-Raqa, Shaya Y. [Department of Chemistry, Faculty of Science, Taibah University, P.O. Box 344, Al-Madinah Al Munawwrah (Saudi Arabia); Durmuş, Mahmut, E-mail: durmus@gtu.edu.tr [Gebze Technical University, Department of Chemistry, P.O. Box 141, Gebze 41400, Kocaeli (Turkey)

    2016-05-15

    The symmetrical zinc(II) phthalocyanines conjugated with 9,10-dioctyl-6,7-dimethoxy-2,3-dioxytriptycene or 9,10-diundecyl-6,7-dimethoxy-2,3-dioxytriptycene moieties were synthesized in this study. These novel phthalocyanines were characterized by standard characterization techniques such as {sup 1}H-NMR, FT-IR, UV–vis, Mass and Elemental Analysis. All these phthalocyanines showed highly solubility and formed non-aggregated monomeric species in most of the organic solvents. Their photochemical properties such as singlet oxygen, and photodegradation quantum yields, and photophysical properties including fluorescence quantum yields and lifetimes were investigated in toluene. The fluorescence quenching behavior of the studied zinc(II) phthalocyanines by the addition of 1,4-benzoquinone were also described in toluene.

  12. Enhancing photophysical and photochemical properties of zinc(II) phthalocyanine dyes by substitution of triptycene moieties

    International Nuclear Information System (INIS)

    Al-Sohaimi, Bander Roshadan; Pişkin, Mehmet; Aljuhani, Ateyatallah; Al-Raqa, Shaya Y.; Durmuş, Mahmut

    2016-01-01

    The symmetrical zinc(II) phthalocyanines conjugated with 9,10-dioctyl-6,7-dimethoxy-2,3-dioxytriptycene or 9,10-diundecyl-6,7-dimethoxy-2,3-dioxytriptycene moieties were synthesized in this study. These novel phthalocyanines were characterized by standard characterization techniques such as 1 H-NMR, FT-IR, UV–vis, Mass and Elemental Analysis. All these phthalocyanines showed highly solubility and formed non-aggregated monomeric species in most of the organic solvents. Their photochemical properties such as singlet oxygen, and photodegradation quantum yields, and photophysical properties including fluorescence quantum yields and lifetimes were investigated in toluene. The fluorescence quenching behavior of the studied zinc(II) phthalocyanines by the addition of 1,4-benzoquinone were also described in toluene.

  13. Molecular Polygons Probe the Role of Intramolecular Strain in the Photophysics of π-Conjugated Chromophores.

    Science.gov (United States)

    Wilhelm, Philipp; Vogelsang, Jan; Poluektov, Georgiy; Schönfelder, Nina; Keller, Tristan J; Jester, Stefan-Sven; Höger, Sigurd; Lupton, John M

    2017-01-24

    π-Conjugated segments, chromophores, are the electronically active units of polymer materials used in organic electronics. To elucidate the effect of the bending of these linear moieties on elementary electronic properties, such as luminescence color and radiative rate, we introduce a series of molecular polygons. The π-system in these molecules becomes so distorted in bichromophores (digons) that these absorb and emit light of arbitrary polarization: any part of the chain absorbs and emits radiation with equal probability. Bending leads to a cancellation of transition dipole moment (TDM), increasing excited-state lifetime. Simultaneously, fluorescence shifts to the red as radiative transitions require mixing of the excited state with vibrational modes. However, strain can become so large that excited-state localization on shorter units of the chain occurs, compensating TDM cancellation. The underlying correlations between shape and photophysics can only be resolved in single molecules. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. A photophysical study of two fluorogen-activating proteins bound to their cognate fluorogens

    Energy Technology Data Exchange (ETDEWEB)

    Gaiotto, Tiziano [Los Alamos National Laboratory; Nguyen, Hau B [Los Alamos National Laboratory; Jung, Jaemyeong [Los Alamos National Laboratory; Bradbury, Andrew M [Los Alamos National Laboratory; Gnanakaran, S. [Los Alamos National Laboratory; Schmidt, Jurgen G [Los Alamos National Laboratory; Waldo, Geoffrey S [Los Alamos National Laboratory; Goodwin, Peter M [Los Alamos National Laboratory

    2010-12-14

    We are exploring the feasibility of using recently developed flu orogen-activating proteins (FAPs) as reporters for single-molecule imaging. FAPs are single-chain antibodies choosen to specifically bind small chromophoric molecules termed f1uorogens. Upon binding to its cognate FAP the fluorescence quantum yield of the fluorogen can increase substantially giving rise to a fluorescent complex. Based on the seminal work of Szent-Gyorgyi et al. (Nature Biotechnology, Volume 26, Number 2, pp 235-240, 2008) we have chosen to study two fluorogen-activating single-chain antibodies, HL 1.0.1-TOI and H6-MG bound to their cognate fluorogens, thiazole orange and malachite green derivatives, respectively. Here we use fluorescence correlation spectroscopy study the photophysics of these fluorescent complexes.

  15. Photophysical properties of open-framework germanates templated by nickel complexes

    KAUST Repository

    Peskov, Maxim; Schwingenschlö gl, Udo

    2014-01-01

    Open-framework germanates are a group of germanium oxides with a well-defined porous structure, suitable for ion-exchange and gas adsorption applications. Recently, Ni incorporation into the porous structure by establishing Ge-O-Ni bonds with the molecular complexes [Ni(H 2N(CH2)2NH2)2] was realized. We investigate the optical and electronic features of these systems (SUT-1 and SUT-2) from first principles. To describe the photophysical behavior, we analyze the bonding between the Ni and nearest-neighboring atoms and simulate the absorption spectra. Because of their optical characteristics, germania-based nanomaterials are expected to be essential components of future optical and electronic devices. We discuss to what extent molecular transition-metal complexes embedded into porous germanium oxide can modify the optical response to potentially expand the area of applications. This journal is © the Partner Organisations 2014.

  16. Tunable photophysical processes of porphyrin macrocycles on the surface of ZnO nanoparticles

    KAUST Repository

    Parida, Manas R.

    2015-01-23

    We investigated the impact of the molecular structure of cationic porphyrins on the degree of electrostatic interactions with zinc oxide nanoparticles (ZnO NPs) using steady-state and time-resolved fluorescence and transient absorption spectroscopy. Our results demonstrate that the number of cationic pyridinium units has a crucial impact on the photophysics of the porphyrin macrocycle. Fluorescence enhancement, relative to initial free porphyrin fluorescence, was found to be tuned from 3.4 to 1.3 times higher by reducing the number of cationic substituents on the porphyrin from 4 to 2. The resulting enhancement of the intensity of the fluorescence is attributed to the decrease in the intramolecular charge transfer (ICT) character between the porphyrin cavity and its meso substituent. The novel findings reported in this work provide an understanding of the key variables involved in nanoassembly, paving the way toward optimizing the interfacial chemistry of porphyrin-ZnO NP assembly for photodynamic therapy and energy conversion.

  17. Photosensitivity to Triflusal: Formation of a Photoadduct with Ubiquitin Demonstrated by Photophysical and Proteomic Techniques

    Directory of Open Access Journals (Sweden)

    E Nuin

    2016-08-01

    Full Text Available Triflusal is a platelet aggregation inhibitor chemically related to acetylsalicylic acid, which is used for the prevention and/or treatment of vascular thromboembolisms, which acts as a prodrug. Actually, after oral administration it is absorbed primarily in the small intestine, binds to plasma proteins (99% and is rapidly biotransformed in the liver into its deacetylated active metabolite 2-hydroxy-4-trifluoromethylbenzoic acid (HTB. In healthy humans, the half-life of triflusal is ca. 0.5 h, whereas for HTB it is ca. 35 h. From a pharmacological point of view, it is interesting to note that HTB is itself highly active as a platelet anti-aggregant agent. Indeed, studies on the clinical profile of both drug and metabolite have shown no significant differences between them.It has been evidenced that HTB displays ability to induce photoallergy in humans. This phenomenon involves a cell-mediated immune response, which is initiated by covalent binding of a light-activated photosensitizer (or a species derived therefrom to a protein. In this context, small proteins like ubiquitin could be appropriate models for investigating covalent binding by means of MS/MS and peptide fingerprint analysis. In previous work, it was shown that HTB forms covalent photoadducts with isolated lysine. Interestingly, ubiquitin contains seven lysine residues that could be modified by a similar reaction. With this background, the aim of the present work is to explore adduct formation between the triflusal metabolite and ubiquitin as model protein upon sunlight irradiation, combining proteomic and photophysical (fluorescence and laser flash photolysis techniques.Photophysical and proteomic analysis demonstrate monoadduct formation as the major outcome of the reaction. Interestingly, addition can take place at any of the -amino groups of the lysine residues of the protein and involves replacement of the trifluoromethyl moiety with a new amide function. This process can in

  18. Effect of diblock copolymer properties on the photophysical properties of dendrimer silicon phthalocyanine nanoconjugates

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kuizhi [Fujian Normal University, College of Materials Science & Engineering, Fujian Provincial Key Laboratory of Polymer Materials (China); Pan, Sujuan [Fujian Normal University, College of Chemistry & Engineering (China); Zhuang, Xuemei [Fuzhou No.2 Hospital (China); Lv, Hafei; Que, Shoulin [Fujian Normal University, College of Chemistry & Engineering (China); Xie, Shusen; Yang, Hongqin, E-mail: hqyang@fjnu.edu.cn [Fujian Normal University, Key Laboratory of Optoelectronic Science and Technology for Medicine of Ministry of Education (China); Peng, Yiru, E-mail: yirupeng@fjnu.edu.cn [Fujian Normal University, College of Chemistry & Engineering (China)

    2016-07-15

    1–2 generation poly(benzyl aryl ether) dendrimer silicon phthalocyanines with axially disubstituted cyano terminal functionalities (G{sub n}-DSiPc(CN){sub 4n}, (G{sub n} = n-generation dendrimer, n = 1–2)) were synthesized. Their structures were characterized by elemental analysis, IR, {sup 1}H NMR, and ESI-MS. Polymeric nanoparticles (G{sub n}-DSiPc(CN){sub 4n}/m) were formed through encapsulating G{sub n}-DSiPc(CN){sub 4n} into three monomethoxyl poly(ethylene glycol)-poly(ε-caprolactone) diblock copolymers (MPEG–PCL) with different hydrophilic/hydrophobic proportion, respectively. The effect of dendritic generation and the hydrophilic/hydrophobic proportion of diblock copolymers on the UV/Vis and fluorescence spectra of G{sub n}-DSiPc(CN){sub 4n} and G{sub n}-DSiPc(CN){sub 4n}/m were studied. The photophysical properties of polymeric nanoparticles exhibited dendritic generation and hydrophilic/hydrophobic proportion dependence. The fluorescence intensities and lifetimes of G{sub n}-DSiPc(CN){sub 4n}/m were lower than the corresponding free dendrimer phthalocyanines. G{sub n}-DSiPc(CN){sub 4n} encapsulated into MPEG–PCL with hydrophilic/hydrophobic molecular weight ratio 2000:4000 exhibited excellent photophysical property. The mean diameter of MPEG{sub 2000}–PCL{sub 2000} micelles was about 70 nm, which decreased when loaded with G{sub n}-DSiPc(CN){sub 4n}.Graphical abstract .

  19. Photophysical and adsorption properties of pyronin B in natural bentonite clay dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Rostami, Mohammad Reza [Department of Chemistry, Faculty of Sciences, Atatürk University, 25240, Erzurum (Turkey); Kaya, Mehmet [Recep Tayyip Erdoğan University, Faculty of Arts and Sciences, 53100 Rize (Turkey); Gür, Bahri; Onganer, Yavuz [Department of Chemistry, Faculty of Sciences, Atatürk University, 25240, Erzurum (Turkey); Meral, Kadem, E-mail: kademm@atauni.edu.tr [Department of Chemistry, Faculty of Sciences, Atatürk University, 25240, Erzurum (Turkey)

    2015-12-30

    Graphical abstract: The molecular aggregation of PyB in bentonite aqueous dispersion is observed by using molecular absorption spectrum. - Highlights: • Molecular behavior of PyB adsorbed on bentonite was spectroscopically followed. • H-aggregates of PyB in bentonite aqueous dispersion were formed. • The adsorption characteristics of PyB on bentonite particles were determined. - Abstract: The present study focused on the adsorption and photophysical properties of pyronin B (PyB) in bentonite aqueous dispersion. The photophysical properties of PyB in the aqueous dispersion were studied by using UV–vis absorption, steady-state and time-resolved fluorescence spectroscopy techniques. In this concept, the interaction of the dye with bentonite particles in the aqueous dispersion was spectroscopically followed depending on certain parameters such as interaction time, pH and the dye concentration. Obtained spectral data revealed that the aggregate structures (H-type) of PyB in the aqueous dispersion were formed in the dye concentration range studied. The non-fluorescence nature of H-aggregates and the clay minerals governed the fluorescence property of PyB. The mentioned non-radiative processes caused the fluorescence lifetime of the dye to decrease compared to that in water. The adsorption process of PyB on bentonite was examined depending on contact time and initial adsorbate concentration. An adsorption isotherm was good-fitted by the Freundlich model with a linear regression correlation value of 0.999. The adsorption of PyB on bentonite particles was in agreement with pseudo second-order kinetics.

  20. Incentive-Rewarding Mechanism for User-position Control in Mobile Services

    Science.gov (United States)

    Yoshino, Makoto; Sato, Kenichiro; Shinkuma, Ryoichi; Takahashi, Tatsuro

    When the number of users in a service area increases in mobile multimedia services, no individual user can obtain satisfactory radio resources such as bandwidth and signal power because the resources are limited and shared. A solution for such a problem is user-position control. In the user-position control, the operator informs users of better communication areas (or spots) and navigates them to these positions. However, because of subjective costs caused by subjects moving from their original to a new position, they do not always attempt to move. To motivate users to contribute their resources in network services that require resource contributions for users, incentive-rewarding mechanisms have been proposed. However, there are no mechanisms that distribute rewards appropriately according to various subjective factors involving users. Furthermore, since the conventional mechanisms limit how rewards are paid, they are applicable only for the network service they targeted. In this paper, we propose a novel incentive-rewarding mechanism to solve these problems, using an external evaluator and interactive learning agents. We also investigated ways of appropriately controlling rewards based on user contributions and system service quality. We applied the proposed mechanism and reward control to the user-position control, and demonstrated its validity.

  1. Ropivacaine alters the mechanical properties of hamstring tendons: In vitro controlled mechanical testing of tendons from living donors.

    Science.gov (United States)

    Ollivier, M; Sbihi, J; Sbihi, A; Pithioux, M; Parratte, S; Argenson, J-N

    2017-11-01

    Intraarticular or periarticular injection of ropivacaine (RI) is an element of current knee surgery practices. The goal of this study was to determine the effects of RI on the mechanical properties of hamstring tendons. We hypothesized that RI would have a detrimental effect on the mechanical properties of periarticular soft tissues METHODS: A tensile test to failure was performed on 120 hamstring tendon segments harvested during ACL reconstruction surgery in 120 patients. Two sets of tensile tests were done. The first evaluated the effect of RI itself on the mechanical properties of tendons: 30 samples were soaked for 1hour in a 2% RI solution and compared to 30 samples soaked in a saline solution (control group). The second evaluated the effect of RI concentration on the mechanical properties of hamstring tendons: 30 samples were soaked for 1hour in a 2% RI solution and 30 samples were soaked in a 7.5% RI solution. In the first test, 29 samples from each group were analyzed as two samples (one in each group) failed at the grip interface. The specimens exposed to 2% RI had lower ultimate tensile strength (Δ=4.4MPa, P=0.001), strain energy (Δ=13MPa, P=0.001) and Young's modulus (Δ=1.6MPa, P=0.02) than the specimens in the control group. There was no significant difference in the strain at failure between groups (Δ=5%, P=0.3). In the second test, one specimen from the 7.5% RI group failed during the preloading and was excluded. There was no significant difference in terms of the load at failure and ultimate tensile stress (Δ=0.45MPa, P=0.6) and strain energy (Δ=0.49MPa, P=0.49) between the two groups. There were significant differences in terms of elongation at failure (Δ=28%, P=0.0003) and Young's modulus (Δ=2.6MPa, P=0.005), with the specimens exposed to 7.5% RI undergoing greater deformation and having a lower Young's modulus. While local RI injections are widely performed in clinical practice, the results of this in vitro study point to short

  2. Dynamic Modeling and Control of Electromechanical Coupling for Mechanical Elastic Energy Storage System

    Directory of Open Access Journals (Sweden)

    Yang Yu

    2013-01-01

    Full Text Available The structural scheme of mechanical elastic energy storage (MEES system served by permanent magnet synchronous motor (PMSM and bidirectional converters is designed. The aim of the research is to model and control the complex electromechanical system. The mechanical device of the complex system is considered as a node in generalized coordinate system, the terse nonlinear dynamic model of electromechanical coupling for the electromechanical system is constructed through Lagrange-Maxwell energy method, and the detailed deduction of the mathematical model is presented in the paper. The theory of direct feedback linearization (DFL is applied to decouple the nonlinear dynamic model and convert the developed model from nonlinear to linear. The optimal control theory is utilized to accomplish speed tracking control for the linearized system. The simulation results in three different cases show that the proposed nonlinear dynamic model of MEES system is correct; the designed algorithm has a better control performance in contrast with the conventional PI control.

  3. Inner-Learning Mechanism Based Control Scheme for Manipulator with Multitasking and Changing Load

    Directory of Open Access Journals (Sweden)

    Fangzheng Xue

    2014-05-01

    Full Text Available With the rapid development of robot technology and its application, manipulators may face complex tasks and dynamic environments in the coming future, which leads to two challenges of control: multitasking and changing load. In this paper, a novel multicontroller strategy is presented to meet such challenges. The presented controller is composed of three parts: subcontrollers, inner-learning mechanism, and switching rules. Each subcontroller is designed with self-learning skills to fit the changing load under a special task. When a new task comes, switching rule reselects the most suitable subcontroller as the working controller to handle current task instead of the older one. Inner-learning mechanism makes the subcontrollers learn from the working controller when load changes so that the switching action causes smaller tracking error than the traditional switch controller. The results of the simulation experiments on two-degree manipulator show the proposed method effect.

  4. A novel auto-tuning PID control mechanism for nonlinear systems.

    Science.gov (United States)

    Cetin, Meric; Iplikci, Serdar

    2015-09-01

    In this paper, a novel Runge-Kutta (RK) discretization-based model-predictive auto-tuning proportional-integral-derivative controller (RK-PID) is introduced for the control of continuous-time nonlinear systems. The parameters of the PID controller are tuned using RK model of the system through prediction error-square minimization where the predicted information of tracking error provides an enhanced tuning of the parameters. Based on the model-predictive control (MPC) approach, the proposed mechanism provides necessary PID parameter adaptations while generating additive correction terms to assist the initially inadequate PID controller. Efficiency of the proposed mechanism has been tested on two experimental real-time systems: an unstable single-input single-output (SISO) nonlinear magnetic-levitation system and a nonlinear multi-input multi-output (MIMO) liquid-level system. RK-PID has been compared to standard PID, standard nonlinear MPC (NMPC), RK-MPC and conventional sliding-mode control (SMC) methods in terms of control performance, robustness, computational complexity and design issue. The proposed mechanism exhibits acceptable tuning and control performance with very small steady-state tracking errors, and provides very short settling time for parameter convergence. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  5. Computation and Communication Evaluation of an Authentication Mechanism for Time-Triggered Networked Control Systems

    Science.gov (United States)

    Martins, Goncalo; Moondra, Arul; Dubey, Abhishek; Bhattacharjee, Anirban; Koutsoukos, Xenofon D.

    2016-01-01

    In modern networked control applications, confidentiality and integrity are important features to address in order to prevent against attacks. Moreover, network control systems are a fundamental part of the communication components of current cyber-physical systems (e.g., automotive communications). Many networked control systems employ Time-Triggered (TT) architectures that provide mechanisms enabling the exchange of precise and synchronous messages. TT systems have computation and communication constraints, and with the aim to enable secure communications in the network, it is important to evaluate the computational and communication overhead of implementing secure communication mechanisms. This paper presents a comprehensive analysis and evaluation of the effects of adding a Hash-based Message Authentication (HMAC) to TT networked control systems. The contributions of the paper include (1) the analysis and experimental validation of the communication overhead, as well as a scalability analysis that utilizes the experimental result for both wired and wireless platforms and (2) an experimental evaluation of the computational overhead of HMAC based on a kernel-level Linux implementation. An automotive application is used as an example, and the results show that it is feasible to implement a secure communication mechanism without interfering with the existing automotive controller execution times. The methods and results of the paper can be used for evaluating the performance impact of security mechanisms and, thus, for the design of secure wired and wireless TT networked control systems. PMID:27463718

  6. Semi-degradable poly(β-amino ester) networks with temporally controlled enhancement of mechanical properties.

    Science.gov (United States)

    Safranski, David L; Weiss, Daiana; Clark, J Brian; Taylor, W Robert; Gall, Ken

    2014-08-01

    Biodegradable polymers are clinically used in numerous biomedical applications, and classically show a loss of mechanical properties within weeks of implantation. This work demonstrates a new class of semi-degradable polymers that show an increase in mechanical properties through degradation via a controlled shift in a thermal transition. Semi-degradable polymer networks, poly(β-amino ester)-co-methyl methacrylate, were formed from a low glass transition temperature crosslinker, poly(β-amino ester), and high glass transition temperature monomer, methyl methacrylate, which degraded in a manner dependent upon the crosslinker chemical structure. In vitro and in vivo degradation revealed changes in mechanical behavior due to the degradation of the crosslinker from the polymer network. This novel polymer system demonstrates a strategy to temporally control the mechanical behavior of polymers and to enhance the initial performance of smart biomedical devices. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  7. Neural mechanisms of interference control in working memory: effects of interference expectancy and fluid intelligence.

    Directory of Open Access Journals (Sweden)

    Gregory C Burgess

    2010-09-01

    Full Text Available A critical aspect of executive control is the ability to limit the adverse effects of interference. Previous studies have shown activation of left ventrolateral prefrontal cortex after the onset of interference, suggesting that interference may be resolved in a reactive manner. However, we suggest that interference control may also operate in a proactive manner to prevent effects of interference. The current study investigated the temporal dynamics of interference control by varying two factors - interference expectancy and fluid intelligence (gF - that could influence whether interference control operates proactively versus reactively.A modified version of the recent negatives task was utilized. Interference expectancy was manipulated across task blocks by changing the proportion of recent negative (interference trials versus recent positive (facilitation trials. Furthermore, we explored whether gF affected the tendency to utilize specific interference control mechanisms. When interference expectancy was low, activity in lateral prefrontal cortex replicated prior results showing a reactive control pattern (i.e., interference-sensitivity during probe period. In contrast, when interference expectancy was high, bilateral prefrontal cortex activation was more indicative of proactive control mechanisms (interference-related effects prior to the probe period. Additional results suggested that the proactive control pattern was more evident in high gF individuals, whereas the reactive control pattern was more evident in low gF individuals.The results suggest the presence of two neural mechanisms of interference control, with the differential expression of these mechanisms modulated by both experimental (e.g., expectancy effects and individual difference (e.g., gF factors.

  8. Distributed power and control actuation in the thoracic mechanics of a robotic insect

    International Nuclear Information System (INIS)

    Finio, Benjamin M; Wood, Robert J

    2010-01-01

    Recent advances in the understanding of biological flight have inspired roboticists to create flapping-wing vehicles on the scale of insects and small birds. While our understanding of the wing kinematics, flight musculature and neuromotor control systems of insects has expanded, in practice it has proven quite difficult to construct an at-scale mechanical device capable of similar flight performance. One of the key challenges is the development of an effective and efficient transmission mechanism to control wing motions. Here we present multiple insect-scale robotic thorax designs capable of producing asymmetric wing kinematics similar to those observed in nature and utilized by dipteran insects to maneuver. Inspired by the thoracic mechanics of dipteran insects, which entail a morphological separation of power and control muscles, these designs show that such distributed actuation can also modulate wing motion in a robotic design.

  9. Distributed power and control actuation in the thoracic mechanics of a robotic insect.

    Science.gov (United States)

    Finio, Benjamin M; Wood, Robert J

    2010-12-01

    Recent advances in the understanding of biological flight have inspired roboticists to create flapping-wing vehicles on the scale of insects and small birds. While our understanding of the wing kinematics, flight musculature and neuromotor control systems of insects has expanded, in practice it has proven quite difficult to construct an at-scale mechanical device capable of similar flight performance. One of the key challenges is the development of an effective and efficient transmission mechanism to control wing motions. Here we present multiple insect-scale robotic thorax designs capable of producing asymmetric wing kinematics similar to those observed in nature and utilized by dipteran insects to maneuver. Inspired by the thoracic mechanics of dipteran insects, which entail a morphological separation of power and control muscles, these designs show that such distributed actuation can also modulate wing motion in a robotic design.

  10. Substitution Relationship Between The Agency Problem Control Mechanisms in Malaysia: Simultaneous Equation Analysis

    Directory of Open Access Journals (Sweden)

    D. Agus Harjito

    2009-05-01

    Full Text Available This study investigates the substitution relationship (substitutability between debt policy, insider ownership, and dividend policy as the agency problem control mechanism in Malaysia. If the substitution relationship exists between the agency control mechanisms, the agency problem can be reduced through this relationship. Reducing the agency problem as a result can increase the firm value proxied by Tobin’s Q. This study employs 396 firms sample listed on Malaysian Bourse from 2001 to 2004. To achieves the objectives, this study uses two-stage least square method. The results of this study indicate that the substitutability between debt policy, insider ownership, and dividend policy as agency problem control mechanism does not fully exist in Malaysia. Apparently the substitutability only exists for debt policy and dividend. There is no substitution between debt policy and insider ownership as well as between dividend policy and insider ownership. Key words: debt policy, insider ownership, dividend policy, agency problem, firm value

  11. Cognitive Self-Scheduled Mechanism for Access Control in Noisy Vehicular Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    Mario Manzano

    2015-01-01

    Full Text Available Within the challenging environment of intelligent transportation systems (ITS, networked control systems such as platooning guidance of autonomous vehicles require innovative mechanisms to provide real-time communications. Although several proposals are currently under discussion, the design of a rapid, efficient, flexible, and reliable medium access control mechanism which meets the specific constraints of such real-time communications applications remains unsolved in this highly dynamic environment. However, cognitive radio (CR combines the capacity to sense the radio spectrum with the flexibility to adapt to transmission parameters in order to maximize system performance and has thus become an effective approach for the design of dynamic spectrum access (DSA mechanisms. This paper presents the enhanced noncooperative cognitive division multiple access (ENCCMA proposal combining time division multiple access (TDMA and frequency division multiple access (FDMA schemes with CR techniques to obtain a mechanism fulfilling the requirements of real-time communications. The analysis presented here considers the IEEE WAVE and 802.11p as reference standards; however, the proposed medium access control (MAC mechanism can be adapted to operate on the physical layer of different standards. The mechanism also offers the advantage of avoiding signaling, thus enhancing system autonomy as well as behavior in adverse scenarios.

  12. Movement goals and feedback and feedforward control mechanisms in speech production.

    Science.gov (United States)

    Perkell, Joseph S

    2012-09-01

    Studies of speech motor control are described that support a theoretical framework in which fundamental control variables for phonemic movements are multi-dimensional regions in auditory and somatosensory spaces. Auditory feedback is used to acquire and maintain auditory goals and in the development and function of feedback and feedforward control mechanisms. Several lines of evidence support the idea that speakers with more acute sensory discrimination acquire more distinct goal regions and therefore produce speech sounds with greater contrast. Feedback modification findings indicate that fluently produced sound sequences are encoded as feedforward commands, and feedback control serves to correct mismatches between expected and produced sensory consequences.

  13. Modeling and Control of the Redundant Parallel Adjustment Mechanism on a Deployable Antenna Panel

    Directory of Open Access Journals (Sweden)

    Lili Tian

    2016-10-01

    Full Text Available With the aim of developing multiple input and multiple output (MIMO coupling systems with a redundant parallel adjustment mechanism on the deployable antenna panel, a structural control integrated design methodology is proposed in this paper. Firstly, the modal information from the finite element model of the structure of the antenna panel is extracted, and then the mathematical model is established with the Hamilton principle; Secondly, the discrete Linear Quadratic Regulator (LQR controller is added to the model in order to control the actuators and adjust the shape of the panel. Finally, the engineering practicality of the modeling and control method based on finite element analysis simulation is verified.

  14. Controlling Hydrogel Mechanics via Bio-Inspired Polymer-Nanoparticle Bond Dynamics.

    Science.gov (United States)

    Li, Qiaochu; Barrett, Devin G; Messersmith, Phillip B; Holten-Andersen, Niels

    2016-01-26

    Interactions between polymer molecules and inorganic nanoparticles can play a dominant role in nanocomposite material mechanics, yet control of such interfacial interaction dynamics remains a significant challenge particularly in water. This study presents insights on how to engineer hydrogel material mechanics via nanoparticle interface-controlled cross-link dynamics. Inspired by the adhesive chemistry in mussel threads, we have incorporated iron oxide nanoparticles (Fe3O4 NPs) into a catechol-modified polymer network to obtain hydrogels cross-linked via reversible metal-coordination bonds at Fe3O4 NP surfaces. Unique material mechanics result from the supra-molecular cross-link structure dynamics in the gels; in contrast to the previously reported fluid-like dynamics of transient catechol-Fe(3+) cross-links, the catechol-Fe3O4 NP structures provide solid-like yet reversible hydrogel mechanics. The structurally controlled hierarchical mechanics presented here suggest how to develop hydrogels with remote-controlled self-healing dynamics.

  15. Experimental study on the scram of electromagnetic movable coil control rod drive mechanism

    International Nuclear Information System (INIS)

    Sun Changlong; Bo Hanliang; Jiang Shengyao; Zhang Hongchao; Ma Cang; Wang Jinhua; Qin Benke

    2006-01-01

    Electromagnetic movable coil control rod drive mechanism is a new type drive mechanism. The drive mechanism is experimentally studied to gain the characteristic of scram time. Further more, the reason of the different scram phenomena is analyzed and the disciplinarian of scram is also summarized. On the base of series experiments it can be concluded that scram time of AC break is longer than that of DC break and the residual current of coil's can distinctly influence the scram time. The scram time of AC break is 300-700 ms longer than that of DC break. (authors)

  16. Force analysis of the advanced neutron source control rod drive latch mechanism

    International Nuclear Information System (INIS)

    Damiano, B.

    1989-01-01

    The Advanced Neutron Source reactor (ANS), a proposed Department of Energy research reactor currently undergoing conceptual design at the Oak Ridge National Laboratory (ORNL), will generate a thermal neutron flux approximating 10 30 M -2 emdash S -1 . The compact core necessary to produce this flux provides little space for the shim safety control rods, which are located in the central annulus of the core. Without proper control rod drive design, the control rod drive magnets (which hold the control rod latch in a ready-to-scram position) may be unable to support the required load due to their restricted size. This paper describes the force analysis performed on the control rod latch mechanism to determine the fraction of control rod weight transferred to the drive magnet. This information will be useful during latch, control rod drive and magnet design. 5 refs., 12 figs

  17. Mechanism design for the control rods conduction of TRIGA Mark III reactor in the NINR

    International Nuclear Information System (INIS)

    Franco C, A.

    1997-01-01

    This work presents in the first chapter a general studio about the reactor and the importance of control rods in the reactor , the mechaniucal design attending to requisitions that are imposed for conditions of operation of the reactor are present in the second chapter, the narrow relation that exists with the new control console and the mechanism is developed in the thired chapter, this relation from a point of view of an assembly of components is presents in fourth chapter, finally reaches and perspectives of mechanism forming part of project of the automation of reactor TRIGA MARK III, are present in the fifth chapter. (Author)

  18. Virus spreading in wireless sensor networks with a medium access control mechanism

    International Nuclear Information System (INIS)

    Wang Ya-Qi; Yang Xiao-Yuan

    2013-01-01

    In this paper, an extended version of standard susceptible-infected (SI) model is proposed to consider the influence of a medium access control mechanism on virus spreading in wireless sensor networks. Theoretical analysis shows that the medium access control mechanism obviously reduces the density of infected nodes in the networks, which has been ignored in previous studies. It is also found that by increasing the network node density or node communication radius greatly increases the number of infected nodes. The theoretical results are confirmed by numerical simulations. (general)

  19. Effects of Natural Sounds on Pain: A Randomized Controlled Trial with Patients Receiving Mechanical Ventilation Support.

    Science.gov (United States)

    Saadatmand, Vahid; Rejeh, Nahid; Heravi-Karimooi, Majideh; Tadrisi, Sayed Davood; Vaismoradi, Mojtaba; Jordan, Sue

    2015-08-01

    Nonpharmacologic pain management in patients receiving mechanical ventilation support in critical care units is under investigated. Natural sounds may help reduce the potentially harmful effects of anxiety and pain in hospitalized patients. The aim of this study was to examine the effect of pleasant, natural sounds on self-reported pain in patients receiving mechanical ventilation support, using a pragmatic parallel-arm, randomized controlled trial. The study was conducted in a general adult intensive care unit of a high-turnover teaching hospital, in Tehran, Iran. Between October 2011 and June 2012, we recruited 60 patients receiving mechanical ventilation support to the intervention (n = 30) and control arms (n = 30) of a pragmatic parallel-group, randomized controlled trial. Participants in both arms wore headphones for 90 minutes. Those in the intervention arm heard pleasant, natural sounds, whereas those in the control arm heard nothing. Outcome measures included the self-reported visual analog scale for pain at baseline; 30, 60, and 90 minutes into the intervention; and 30 minutes post-intervention. All patients approached agreed to participate. The trial arms were similar at baseline. Pain scores in the intervention arm fell and were significantly lower than in the control arm at each time point (p natural sounds via headphones is a simple, safe, nonpharmacologic nursing intervention that may be used to allay pain for up to 120 minutes in patients receiving mechanical ventilation support. Copyright © 2015 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  20. Development of safe mechanism for surgical robots using equilibrium point control method.

    Science.gov (United States)

    Park, Shinsuk; Lim, Hokjin; Kim, Byeong-sang; Song, Jae-bok

    2006-01-01

    This paper introduces a novel mechanism for surgical robotic systems to generate human arm-like compliant motion. The mechanism is based on the idea of the equilibrium point control hypothesis which claims that multi-joint limb movements are achieved by shifting the limbs' equilibrium positions defined by neuromuscular activity. The equilibrium point control can be implemented on a robot manipulator by installing two actuators at each joint of the manipulator, one to control the joint position, and the other to control the joint stiffness. This double-actuator mechanism allows us to arbitrarily manipulate the stiffness (or impedance) of a robotic manipulator as well as its position. Also, the force at the end-effector can be estimated based on joint stiffness and joint angle changes without using force transducers. A two-link manipulator and a three-link manipulator with the double-actuator units have been developed, and experiments and simulation results show the potential of the proposed approach. By creating the human arm-like behavior, this mechanism can improve the performance of robot manipulators to execute stable and safe movement in surgical environments by using a simple control scheme.

  1. A statistical model of uplink inter-cell interference with slow and fast power control mechanisms

    KAUST Repository

    Tabassum, Hina

    2013-09-01

    Uplink power control is in essence an interference mitigation technique that aims at minimizing the inter-cell interference (ICI) in cellular networks by reducing the transmit power levels of the mobile users while maintaining their target received signal quality levels at base stations. Power control mechanisms directly impact the interference dynamics and, thus, affect the overall achievable capacity and consumed power in cellular networks. Due to the stochastic nature of wireless channels and mobile users\\' locations, it is important to derive theoretical models for ICI that can capture the impact of design alternatives related to power control mechanisms. To this end, we derive and verify a novel statistical model for uplink ICI in Generalized-K composite fading environments as a function of various slow and fast power control mechanisms. The derived expressions are then utilized to quantify numerically key network performance metrics that include average resource fairness, average reduction in power consumption, and ergodic capacity. The accuracy of the derived expressions is validated via Monte-Carlo simulations. Results are generated for multiple network scenarios, and insights are extracted to assess various power control mechanisms as a function of system parameters. © 1972-2012 IEEE.

  2. A statistical model of uplink inter-cell interference with slow and fast power control mechanisms

    KAUST Repository

    Tabassum, Hina; Yilmaz, Ferkan; Dawy, Zaher; Alouini, Mohamed-Slim

    2013-01-01

    Uplink power control is in essence an interference mitigation technique that aims at minimizing the inter-cell interference (ICI) in cellular networks by reducing the transmit power levels of the mobile users while maintaining their target received signal quality levels at base stations. Power control mechanisms directly impact the interference dynamics and, thus, affect the overall achievable capacity and consumed power in cellular networks. Due to the stochastic nature of wireless channels and mobile users' locations, it is important to derive theoretical models for ICI that can capture the impact of design alternatives related to power control mechanisms. To this end, we derive and verify a novel statistical model for uplink ICI in Generalized-K composite fading environments as a function of various slow and fast power control mechanisms. The derived expressions are then utilized to quantify numerically key network performance metrics that include average resource fairness, average reduction in power consumption, and ergodic capacity. The accuracy of the derived expressions is validated via Monte-Carlo simulations. Results are generated for multiple network scenarios, and insights are extracted to assess various power control mechanisms as a function of system parameters. © 1972-2012 IEEE.

  3. Cascade Controller Including Back-stepping for Hydraulic-Mechanical Systems

    DEFF Research Database (Denmark)

    Choux, Martin; Hovland, Geir; Blanke, Mogens

    2012-01-01

    Development of a cascade controller structure including adaptive backstepping for a nonlinear hydraulic-mechanical system is considered in this paper where a dynamic friction (LuGre) model is included to obtain the necessary accuracy. The paper compares the performance of two variants of an adapt......Development of a cascade controller structure including adaptive backstepping for a nonlinear hydraulic-mechanical system is considered in this paper where a dynamic friction (LuGre) model is included to obtain the necessary accuracy. The paper compares the performance of two variants...... of an adaptive backstepping tracking controller with earlier results. The new control architecture is analysed and enhanced tracking performance is demonstrated when including the extended friction model. The complexity of the backstepping procedure is significantly reduced due to the cascade structure. Hence...

  4. Hard and soft sub-time-optimal controllers for a mechanical system with uncertain mass

    DEFF Research Database (Denmark)

    Kulczycki, P.; Wisniewski, Rafal; Kowalski, P.

    2004-01-01

    An essential limitation in using the classical optimal control has been its limited robustness to modeling inadequacies and perturbations. This paper presents conceptions of two practical control structures based on the time-optimal approach: hard and soft ones. The hard structure is defined...... by parameters selected in accordance with the rules of the statistical decision theory; however, the soft structure allows additionally to eliminate rapid changes in control values. The object is a basic mechanical system, with uncertain (also non-stationary) mass treated as a stochastic process....... The methodology proposed here is of a universal nature and may easily be applied with respect to other elements of uncertainty of time-optimal controlled mechanical systems....

  5. Hard and soft Sub-Time-Optimal Controllers for a Mechanical System with Uncertain Mass

    DEFF Research Database (Denmark)

    Kulczycki, P.; Wisniewski, Rafal; Kowalski, P.

    2005-01-01

    An essential limitation in using the classical optimal control has been its limited robustness to modeling inadequacies and perturbations. This paper presents conceptions of two practical control structures based on the time-optimal approach: hard and soft ones. The hard structure is defined...... by parameters selected in accordance with the rules of the statistical decision theory; however, the soft structure allows additionally to eliminate rapid changes in control values. The object is a basic mechanical system, with uncertain (also non-stationary) mass treated as a stochastic process....... The methodology proposed here is of a universal nature and may easily be applied with respect to other elements of uncertainty of time-optimal controlled mechanical systems....

  6. Mechanisms of Cell Polarity-Controlled Epithelial Homeostasis and Immunity in the Intestine.

    Science.gov (United States)

    Klunder, Leon J; Faber, Klaas Nico; Dijkstra, Gerard; van IJzendoorn, Sven C D

    2017-07-05

    Intestinal epithelial cell polarity is instrumental to maintain epithelial homeostasis and balance communications between the gut lumen and bodily tissue, thereby controlling the defense against gastrointestinal pathogens and maintenance of immune tolerance to commensal bacteria. In this review, we highlight recent advances with regard to the molecular mechanisms of cell polarity-controlled epithelial homeostasis and immunity in the human intestine. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  7. Adaptive kanban control mechanism for a single-stage hybrid system

    Science.gov (United States)

    Korugan, Aybek; Gupta, Surendra M.

    2002-02-01

    In this paper, we consider a hybrid manufacturing system with two discrete production lines. Here the output of either production line can satisfy the demand for the same type of product without any penalties. The interarrival times for demand occurrences and service completions are exponentially distributed i.i.d. variables. In order to control this type of manufacturing system we suggest a single stage pull type control mechanism with adaptive kanbans and state independent routing of the production information.

  8. Radon mitigation with mechanical supply and exhaust ventilation adjusted by a pressure control unit

    International Nuclear Information System (INIS)

    Kokotti, H.; Keskikuru, T.; Kalliokoski, P.

    1993-01-01

    Effective ventilation and positive or low negative pressure indoors are suggested to low indoor radon levels. The aim of this study is to develop and to test an equipment, which makes it possible to achieve simultaneously effective ventilation and minimum outdoor-pressure difference. The unit includes mechanical supply and exhaust air fans, a exchanger and a pressure control unit in direct digital control (DDC), which adjusts continuously air exchange based on the pressure difference transmitter information. (orig.). (8 refs., 6 figs.)

  9. Electromagnetic analysis of locking device for SMART control element drive mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Hyung; Kim, J. I.; Kim, J. H. [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-09-01

    A numerical electromagnetic analysis was performed for the control rod locking device which is installed in the control element drive mechanism of integral reactor, SMART. A plunger model for the electromagnetic analysis of the locking device was developed and theoretical bases for the model were established. Design parameters related to plunger pushing force were identified, and the optimum design point was determined by analysing the trend of the plunger pushing force with finite element method. 8 refs., 22 figs., 2 tabs. (Author)

  10. Controller design for flexible, distributed parameter mechanical arms via combined state space and frequency domain techniques

    Science.gov (United States)

    Book, W. J.; Majett, M.

    1982-01-01

    The potential benefits of the ability to control more flexible mechanical arms are discussed. A justification is made in terms of speed of movement. A new controller design procedure is then developed to provide this capability. It uses both a frequency domain representation and a state variable representation of the arm model. The frequency domain model is used to update the modal state variable model to insure decoupled states. The technique is applied to a simple example with encouraging results.

  11. Electromagnetic analysis of locking device for SMART control element drive mechanism

    International Nuclear Information System (INIS)

    Heo, H.; Kim, J. I.; Kim, J. H.; Kim, Y. W.; Park, J. S.

    1998-01-01

    A numerical electromagnetic analysis was performed for the control rod locking device which is installed in the control element drive mechanism of integral reactor, SMART. A plunger model for the electromagnetic analysis of the locking device was developed and theoretical bases for the model were established. Design parameters related to plunger pushing force were identified, and the optimum design point was determined by analyzing the trend of the plunger pushing force with finite element method

  12. Photo-physical and interactional behavior of two members of group B vitamins in different solvent media

    Science.gov (United States)

    Zakerhamidi, M. S.; Zare Haghighi, L.; Seyed Ahmadian, S. M.

    2017-09-01

    In this paper, absorption and fluorescence spectra of vitamin B12 (cyanocobalamin) and vitamin B6 (pyridoxine) were recorded in solvents with different polarity, at room temperature. These vitamins' photo-physical behavior depends strongly on the solvent's nature along with different attached groups in their structures. In order to investigate the solvent-solute interactions and environmental effect on spectral variations, linear solvation energy relationships concept, suggested by Kamlet and Taft was used. Solvatochromic method was also used for measuring the ground and excited state dipole moments of these vitamins. According to our experimental results, dipole moment of these groups of vitamins in excited state is larger than ground state. Furthermore, obtained photo-physical and interactional properties of used vitamins can give important information on how this group of vitamins behaves in biological systems.

  13. Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II complexes

    Directory of Open Access Journals (Sweden)

    Amaresh Mishra

    2013-05-01

    Full Text Available Pd-catalyzed Sonogashira cross-coupling reactions were used to synthesize novel π-conjugated oligothienylene-ethynylene dendrons and their corresponding terpyridine-based ligands. Their complexation with Ru(II led to interesting novel metallodendrimers with rich spectroscopic properties. All new compounds were fully characterized by 1H and 13C NMR, as well as MALDI–TOF mass spectra. Density functional theory (DFT calculations performed on these complexes gave more insight into the molecular orbital distributions. Photophysical and electrochemical studies were carried out in order to elucidate structure–property relationships and the effect of the dendritic structure on the metal complexes. Photophysical studies of the complexes revealed broad absorption spectra covering from 250 to 600 nm and high molar extinction coefficients. The MLCT emission of these complexes were significantly red-shifted (up to 115 nm compared to the parent [Ru(tpy2]2+ complex.

  14. Mechanics

    CERN Document Server

    Hartog, J P Den

    1961-01-01

    First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

  15. Coupling Mechanism and Decoupled Suspension Control Model of a Half Car

    Directory of Open Access Journals (Sweden)

    Hailong Zhang

    2016-01-01

    Full Text Available A structure decoupling control strategy of half-car suspension is proposed to fully decouple the system into independent front and rear quarter-car suspensions in this paper. The coupling mechanism of half-car suspension is firstly revealed and formulated with coupled damping force (CDF in a linear function. Moreover, a novel dual dampers-based controllable quarter-car suspension structure is proposed to realize the independent control of pitch and vertical motions of the half car, in which a newly added controllable damper is suggested to be installed between the lower control arm and connection rod in conventional quarter-car suspension structure. The suggested damper constantly regulates the half-car pitch motion posture in a smooth and steady operation condition meantime achieving the expected completely structure decoupled control of the half-car suspension, by compensating the evolved CDF.

  16. Nonlinear Lyapunov-based boundary control of distributed heat transfer mechanisms in membrane distillation plant

    KAUST Repository

    Eleiwi, Fadi

    2015-07-01

    This paper presents a nonlinear Lyapunov-based boundary control for the temperature difference of a membrane distillation boundary layers. The heat transfer mechanisms inside the process are modeled with a 2D advection-diffusion equation. The model is semi-descretized in space, and a nonlinear state-space representation is provided. The control is designed to force the temperature difference along the membrane sides to track a desired reference asymptotically, and hence a desired flux would be generated. Certain constraints are put on the control law inputs to be within an economic range of energy supplies. The effect of the controller gain is discussed. Simulations with real process parameters for the model, and the controller are provided. © 2015 American Automatic Control Council.

  17. Examining the mechanisms of overgeneral autobiographical memory: capture and rumination, and impaired executive control.

    Science.gov (United States)

    Sumner, Jennifer A; Griffith, James W; Mineka, Susan

    2011-02-01

    Overgeneral autobiographical memory (OGM) is an important cognitive phenomenon in depression, but questions remain regarding the underlying mechanisms. The CaR-FA-X model (Williams et al., 2007) proposes three mechanisms that may contribute to OGM, but little work has examined the possible additive and/or interactive effects among them. We examined two mechanisms of CaR-FA-X: capture and rumination, and impaired executive control. We analysed data from undergraduates (N=109) scoring high or low on rumination who were presented with cues of high and low self-relevance on the Autobiographical Memory Test (AMT). Executive control was operationalised as performance on both the Stroop Colour-Word Task and the Controlled Oral Word Association Test (COWAT). Hierarchical generalised linear modelling was used to predict whether participants would generate a specific memory on a trial of the AMT. Higher COWAT scores, lower rumination, and greater cue self-relevance predicted a higher probability of a specific memory. There was also a rumination×cue self-relevance interaction: Higher (vs lower) rumination was associated with a lower probability of a specific memory primarily for low self-relevant cues. We found no evidence of interactions between these mechanisms. Findings are interpreted with respect to current autobiographical memory models. Future directions for OGM mechanism research are discussed. © 2011 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business

  18. Excited-state intramolecular proton transfer (ESIPT) inspired azole-quinoline based fluorophores: Synthesis and photophysical properties study

    Energy Technology Data Exchange (ETDEWEB)

    Padalkar, Vikas S.; Sekar, Nagaiyan, E-mail: n.sekar@ictmumbai.edu.in

    2014-11-15

    7-Hydroxy-3-(4-nitrophenyl)quinoline-6-carboxylic acid was obtained by the condensation reaction of p-amino salicylic acid and 4-nitrophenylmalonadialdehyde which was obtained from phenylacetonitrile through nitration, hydrolysis and Vilsmeier reaction. 7-Hydroxy-3-(4-nitrophenyl) quinoline-6-carboxylic acid was condensed with different o-aminophenols or o-aminothiophenol in ethanol in the presence of phosphorustrichloride. Synthesized quinoline contained benzimidazole and benzothiazole moieties. Photophysical behaviors of these compounds in solvents of different polarities were studied using UV–vis and fluorescence spectroscopy. The compounds showed single absorption in all the studied solvents. The dual emissions (normal emission and ESIPT emission) as well as large Stokes' shift emission pattern were observed for the synthesized fluorophores. The photophysical study shows that the emission properties of the compounds depend on the solvent polarity. The photophysical properties of the compounds were compared with structurally analogous ESIPT quinoline. Thermal stability of the compounds was studied using thermogravimetric analysis and results show that compounds are thermally stable up to 300 °C. The synthesized quinoline derivatives were characterized using elemental analysis, FT-IR and {sup 1}H –NMR, {sup 13}C –NMR spectroscopy and mass spectral analysis. - Highlights: • First and unique study of quinoline derivatives contain ESIPT azole unit at 6-position and hydroxyl group at 7-position. • Compounds are fluorescent with considerable quantum yields. • All compounds showed absorption in ultraviolet region and emission in visible region with large Stokes' shift. • The photophysical properties of new compounds were compared with reported ESIPT quinoline analogous.

  19. Influence of bidentate structure of an aryl phosphine oxide ligand on photophysical properties of its Eu~Ⅲ complex

    Institute of Scientific and Technical Information of China (English)

    许辉; 魏莹; 赵保敏; 黄维

    2010-01-01

    The bidentate phosphine oxide ligand 1,8-bis(diphenylphosphino) naphthalene oxide (NAPO) and its EuⅢ complex 1 Eu(TTA)3(NAPO) (TTA=2-thenoyltrifluoroacetonate) were chosen to study the effect of bidentate phosphine oxide ligand on the photophysical properties of the corresponding complex. The intramolecular energy transfer processes of 1 were studied. The investigation showed that with bidentate structure NAPO could suppress solvent-induced quenching by enforcing the ligand-ligand interaction and the rigidi...

  20. Imaging, photophysical properties and DFT calculations of manganese blue (barium manganate(VI) sulphate)--a modern pigment.

    Science.gov (United States)

    Accorsi, Gianluca; Verri, Giovanni; Acocella, Angela; Zerbetto, Francesco; Lerario, Giovanni; Gigli, Giuseppe; Saunders, David; Billinge, Rachel

    2014-12-18

    Manganese blue is a synthetic barium manganate(VI) sulphate compound that was produced from 1935 to the 1990s and was used both as a blue pigment in works of art and by conservators in the restoration of paintings. The photophysical properties of the compound are described as well as the setup needed to record the spatial distribution of the pigment in works of art.

  1. Control Engineering as a Part of Undergraduate Curriculum for Mechanical Engineering in India

    Science.gov (United States)

    Akhtar, Shagil; Iqbal, Syed Muneeb; Bajpai, Shrish

    2016-01-01

    In this present study we have traced the genesis of control engineering in the scope of mechanical engineering and then some analysis on its recent developments, their increasing need and how this particular subject has evolved machines functioning nowadays specifically its standard of education in India. We have probed this field right from its…

  2. Genetics of mechanisms controlling responses to two major pathogens in broiler and layer chickens

    DEFF Research Database (Denmark)

    Hamzic, Edin

    The objective of this thesis was to improve the understanding of molecular mechanisms controlling the response to two major pathogens, Eimeria maxima (coccidiosis) and infectious bronchitis virus (IBV), in broiler and layer chickens, respectively. Breeding for the improved response to the two...

  3. Universal mechanisms of sound production and control in birds and mammals

    DEFF Research Database (Denmark)

    Elemans, Coen; Rasmussen, Jeppe Have; Herbst, Christian T.

    2015-01-01

    As animals vocalize, their vocal organ transforms motor commands into vocalizations for social communication. In birds, the physical mechanisms by which vocalizations are produced and controlled remain unresolved because of the extreme difficulty in obtaining in vivo measurements. Here, we...... learning and is common to MEAD sound production across birds and mammals, including humans....

  4. Mechanisms controlling the air–sea CO2 flux in the North Sea

    NARCIS (Netherlands)

    Prowe, A.E.F.; Thomas, Helmuth; Pätsch, Johannes; Kühn, Wilfried; Bozec, Yann; Schiettecatte, Laure-Sophie; Borges, Alberto V.; Baar, Hein J.W. de; Paetsch, J; Kuehn, W

    2009-01-01

    The mechanisms driving the air–sea exchange of carbon dioxide (CO2) in the North Sea are investigated using the three-dimensional coupled physical–biogeochemical model ECOHAM (ECOlogical-model, HAMburg). We validate our simulations using field data for the years 2001–2002 and identify the controls

  5. Investigating the Relationship between Governance Mechanisms and the Disclosure of IT Control Weaknesses

    Science.gov (United States)

    Hamdan, Basil

    2012-01-01

    The current research is concerned with exploring the quality of information technology (IT) control over financial reporting systems as reported under Section 404 of the Sarbanes-Oxley Act of 2002. More specifically, this dissertation examines the association between organizational governance mechanisms and the occurrence and subsequent disclosure…

  6. Enhancement of control rod drive mechanism seating position detector for JRR-3

    International Nuclear Information System (INIS)

    Ohuchi, Satoshi; Kurumada, Osamu; Kamiishi, Eigo; Sato, Masayuki; Ikekame, Yoshinori; Wada, Shigeru

    2016-06-01

    The purpose of the control rod drive mechanism seating position detector for JRR-3 is one of methods for confirming the shutdown condition of the reactor and sending out the seat position signal to other systems. The detector has been utilizing more than 25 years with maintenance regularly. However, some troubles occurred recently. Moreover, the detector has already been discontinued, and it is confirmed that the successor detector is unsuitable for the control rod drive mechanism of JRR-3. Therefore, it was necessary to select the adequate detector to the control rod drive mechanism of JRR-3. Accordingly, we built a test device with the aim of verifying several detectors for integrity and function. At the time of the test for performance confirmation, it was occurred unexpected problems. Nevertheless, we devise improvement of the problems and took measures. Thus we were able to make adequate detector for JRR-3 and replace to enhanced detector. This paper reports the Enhanced of Control rod drive mechanism seating position detector. (author)

  7. Children Do Show Negative Priming: Further Evidence for Early Development of an Intact Selective Control Mechanism

    Science.gov (United States)

    Frings, Christian; Feix, Silke; Rothig, Ulrike; Bruser, Charlotte; Junge, Miriam

    2007-01-01

    Reactions to stimuli that were shortly before presented as distractors are usually slowed down; this phenomenon is known as negative priming. Negative priming is an accepted index for tapping into selective control mechanisms. Although this effect is well established for adults, it has been claimed that children do not show negative priming.…

  8. Design issues of a back-pressure-based congestion control mechanism

    NARCIS (Netherlands)

    Malhotra, R.; Mandjes, M.R.H.; Scheinhardt, W.R.W.; Berg, van den J.L.

    2008-01-01

    Congestion control in packet-based networks is often realized by feedback protocols -- in this paper we assess the performance under a back-pressure mechanism that has been proposed and standardized for Ethernet metropolitan networks. Relying on our earlier results for feedback fluid queues, we

  9. Neural Mechanisms of Interference Control and Time Discrimination in Attention-Deficit/Hyperactivity Disorder

    Science.gov (United States)

    Vloet, Timo D.; Gilsbach, Susanne; Neufang, Susanne; Fink, Gereon R.; Herpertz-Dahlmann, Beate; Konrad, Kerstin

    2010-01-01

    Objective: Both executive functions and time perception are typically impaired in subjects with attention-deficit/hyperactivity disorder (ADHD). However, the exact neural mechanisms underlying these deficits remain to be investigated. Method: Fourteen subjects with ADHD and 14 age- and IQ-matched controls (aged 9 through 15 years) were assessed…

  10. Insulator-protected mechanically controlled break junctions for measuring single-molecule conductance in aqueous environments

    NARCIS (Netherlands)

    Muthusubramanian, N.; Galan, E.; Maity, C.; Eelkema, R.; Grozema, F.C.; van der Zant, H.S.J.

    2016-01-01

    We present a method to fabricate insulated gold mechanically controlled break junctions (MCBJ) by coating the metal with a thin layer of aluminum oxide using plasma enhanced atomic layer deposition. The Al2O3 thickness deposited on the MCBJ devices was varied from 2 to 15 nm

  11. Genetic control and regulatory mechanisms of succinoglycan and curdlan biosynthesis in genus Agrobacterium.

    Science.gov (United States)

    Wu, Dan; Li, Ang; Ma, Fang; Yang, Jixian; Xie, Yutong

    2016-07-01

    Agrobacterium is a genus of gram-negative bacteria that can produce several typical exopolysaccharides with commercial uses in the food and pharmaceutical fields. In particular, succinoglycan and curdlan, due to their good quality in high yield, have been employed on an industrial scale comparatively early. Exopolysaccharide biosynthesis is a multiple-step process controlled by different functional genes, and various environmental factors cause changes in exopolysaccharide biosynthesis through regulatory mechanisms. In this mini-review, we focus on the genetic control and regulatory mechanisms of succinoglycan and curdlan produced by Agrobacterium. Some key functional genes and regulatory mechanisms for exopolysaccharide biosynthesis are described, possessing a high potential for application in metabolic engineering to modify exopolysaccharide production and physicochemical properties. This review may contribute to the understanding of exopolysaccharide biosynthesis and exopolysaccharide modification by metabolic engineering methods in Agrobacterium.

  12. Aging considerations for PWR [pressurized water reactor] control rod drive mechanisms and reactor internals

    International Nuclear Information System (INIS)

    Ware, A.G.

    1988-01-01

    This paper describes age-related degradation mechanisms affecting life extension of pressurized water reactor control rod drive mechanisms and reactor internals. The major sources of age-related degradation for control rod drive mechanisms are thermal transients such as plant heatups and cooldowns, latchings and unlatchings, long-term aging effects on electrical insulation, and the high temperature corrosive environment. Flow induced loads, the high-temperature corrosive environment, radiation exposure, and high tensile stresses in bolts all contribute to aging related degradation of reactor internals. Another problem has been wear and fretting of instrument guide tubes. The paper also discusses age-related failures that have occurred to date in pressurized water reactors

  13. Photophysical properties of chirality: Experimental and theoretical studies of (R)- and (S)-binaphthol derivatives as a prototype case

    International Nuclear Information System (INIS)

    Tsuboi, Taiju; An, Zhong-fu; Nakai, Yosuke; Yin, Jun; Chen, Run-feng; Shi, Hui-fang; Huang, Wei

    2013-01-01

    Highlights: ► The effect of chirality on photophysical properties was investigated. ► The same photophysics of enantiomers was observed in solutions. ► But different photoluminescent efficiency and lifetime were found in neat film. ► The different symmetry and formation probability of dimmers may be the main reason. ► The joint experimental and theoretical study explains these differences well. - Abstract: The key monomers of binaphthol-based chiral materials, (R)- and (S)- 6,6′-dibromo-2,2′-bis(octyloxy)- 1,1′-binaphthyl (R–M and S–M, respectively), were synthesized and characterized by UV–vis absorption spectra, circular dichroism (CD) spectra, photoluminescence (PL) lifetime, PL quantum efficiency at room temperature, together with PL spectra at various temperatures between 12 K and 296 K in both film and solution. The photophysical properties of R–M and S–M were investigated in detail with a joint experimental and theoretical study, in order to reveal the effects of chirality on the π-conjugated chiral systems. Higher photoluminescent quantum efficiency and better PL spectra purity in solid film of R–M were observed and discussed

  14. Trajectory control of robot manipulators with closed-kinematic chain mechanism

    Science.gov (United States)

    Nguyen, Charles C.; Pooran, Farhad J.; Premack, Timothy

    1987-01-01

    The problem of Cartesian trajectory control of a closed-kinematic chain mechanism robot manipulator, recently built at CAIR to study the assembly of NASA hardware for the future Space Station, is considered. The study is performed by both computer simulation and experimentation for tracking of three different paths: a straight line, a sinusoid, and a circle. Linearization and pole placement methods are employed to design controller gains. Results show that the controllers are robust and there are good agreements between simulation and experimentation. The results also show excellent tracking quality and small overshoots.

  15. Assessment of current practices in creating and using passwords as a control mechanism for information access

    Directory of Open Access Journals (Sweden)

    P. L. Wessels

    2007-11-01

    Full Text Available One of the critical issues in managing information within an organization is to ensure that proper controls exist and are applied in allowing people access to information. Passwords are used extensively as the main control mechanism to identify users wanting access to systems, applications, data files, network servers or personal information. In this article, the issues involved in selecting and using passwords are discussed and the current practices employed by users in creating and storing passwords to gain access to sensitive information are assessed. The results of this survey conclude that information managers cannot rely only on users to employ proper password control in order to protect sensitive information.

  16. A Nodal-independent and tissue-intrinsic mechanism controls heart-looping chirality

    Science.gov (United States)

    Noël, Emily S.; Verhoeven, Manon; Lagendijk, Anne Karine; Tessadori, Federico; Smith, Kelly; Choorapoikayil, Suma; den Hertog, Jeroen; Bakkers, Jeroen

    2013-11-01

    Breaking left-right symmetry in bilateria is a major event during embryo development that is required for asymmetric organ position, directional organ looping and lateralized organ function in the adult. Asymmetric expression of Nodal-related genes is hypothesized to be the driving force behind regulation of organ laterality. Here we identify a Nodal-independent mechanism that drives asymmetric heart looping in zebrafish embryos. In a unique mutant defective for the Nodal-related southpaw gene, preferential dextral looping in the heart is maintained, whereas gut and brain asymmetries are randomized. As genetic and pharmacological inhibition of Nodal signalling does not abolish heart asymmetry, a yet undiscovered mechanism controls heart chirality. This mechanism is tissue intrinsic, as explanted hearts maintain ex vivo retain chiral looping behaviour and require actin polymerization and myosin II activity. We find that Nodal signalling regulates actin gene expression, supporting a model in which Nodal signalling amplifies this tissue-intrinsic mechanism of heart looping.

  17. On the near UV photophysics of a phenylalanine residue: conformation-dependent ππ* state deactivation revealed by laser spectroscopy of isolated neutral dipeptides.

    Science.gov (United States)

    Loquais, Yohan; Gloaguen, Eric; Alauddin, Mohammad; Brenner, Valérie; Tardivel, Benjamin; Mons, Michel

    2014-10-28

    The primary step of the near UV photophysics of a phenylalanine residue is investigated in one- and two-color pump-probe R2PI nanosecond experiments carried out on specific conformers of the Ac-Gly-Phe-NH2 molecule and related neutral compounds isolated in a supersonic expansion. Compared to toluene, whose ππ* state photophysics is dominated by intersystem crossing with a lifetime of ∼80 ns at the origin, the first ππ* state of Phe in the peptide environment is systematically found to be shorter-lived. The lifetime at the origin of transition is found to be significantly shortened in the presence of a primary amide (-CONH2) group (20-60 ns, depending on the conformer considered), demonstrating the existence of an additional non-radiative relaxation channel related to this chemical group. The quenching effect induced by the peptide environment is still more remarkable beyond the origin of the ππ* state, since vibronic bands of one of the 4 conformers observed (the 27-ribbon conformation) become barely detectable in the ns R2PI experiment, suggesting a significant conformer-selective lifetime shortening (below 100 ps). These results on dipeptides, which extend previous investigations on shorter Phe-containing molecules (N-Ac-Phe-NH2 and N-Ac-Phe-NH-Me), confirm the existence of conformer-dependent non-radiative deactivation processes, whose characteristic timescales range from tens of ns down to hundreds of ps or below. This dynamics is assigned to two distinct mechanisms: a first one, consistent with an excitation energy transfer from the optically active ππ* state to low-lying amide nπ* excited states accessed through conical intersections, especially in the presence of a C-terminal primary amide group (-CONH2); a second one, responsible for the short lifetimes in 2(7) ribbon structures, would be more specifically triggered by phenyl ring vibrational excitations. Implications in terms of spectroscopic probing of Phe in a peptide environment, especially

  18. Performance enhanced design of chaos controller for the mechanical centrifugal flywheel governor system via adaptive dynamic surface control

    Directory of Open Access Journals (Sweden)

    Shaohua Luo

    2016-09-01

    Full Text Available This paper addresses chaos suppression of the mechanical centrifugal flywheel governor system with output constraint and fully unknown parameters via adaptive dynamic surface control. To have a certain understanding of chaotic nature of the mechanical centrifugal flywheel governor system and subsequently design its controller, the useful tools like the phase diagrams and corresponding time histories are employed. By using tangent barrier Lyapunov function, a dynamic surface control scheme with neural network and tracking differentiator is developed to transform chaos oscillation into regular motion and the output constraint rule is not broken in whole process. Plugging second-order tracking differentiator into chaos controller tackles the “explosion of complexity” of backstepping and improves the accuracy in contrast with the first-order filter. Meanwhile, Chebyshev neural network with adaptive law whose input only depends on a subset of Chebyshev polynomials is derived to learn the behavior of unknown dynamics. The boundedness of all signals of the closed-loop system is verified in stability analysis. Finally, the results of numerical simulations illustrate effectiveness and exhibit the superior performance of the proposed scheme by comparing with the existing ADSC method.

  19. Neural mechanisms underlying cognitive control of men with lifelong antisocial behavior.

    Science.gov (United States)

    Schiffer, Boris; Pawliczek, Christina; Mu Ller, Bernhard; Forsting, Michael; Gizewski, Elke; Leygraf, Norbert; Hodgins, Sheilagh

    2014-04-30

    Results of meta-analyses suggested subtle deficits in cognitive control among antisocial individuals. Because almost all studies focused on children with conduct problems or adult psychopaths, however, little is known about cognitive control mechanisms among the majority of persistent violent offenders who present an antisocial personality disorder (ASPD). The present study aimed to determine whether offenders with ASPD, relative to non-offenders, display dysfunction in the neural mechanisms underlying cognitive control and to assess the extent to which these dysfunctions are associated with psychopathic traits and trait impulsivity. Participants comprised 21 violent offenders and 23 non-offenders who underwent event-related functional magnetic resonance imaging while performing a non-verbal Stroop task. The offenders, relative to the non-offenders, exhibited reduced response time interference and a different pattern of conflict- and error-related activity in brain areas involved in cognitive control, attention, language, and emotion processing, that is, the anterior cingulate, dorsolateral prefrontal, superior temporal and postcentral cortices, putamen, thalamus, and amygdala. Moreover, between-group differences in behavioural and neural responses revealed associations with core features of psychopathy and attentional impulsivity. Thus, the results of the present study confirmed the hypothesis that offenders with ASPD display alterations in the neural mechanisms underlying cognitive control and that those alterations relate, at least in part, to personality characteristics. Copyright © 2014. Published by Elsevier Ireland Ltd.

  20. Biologically inspired control and modeling of (biorobotic systems and some applications of fractional calculus in mechanics

    Directory of Open Access Journals (Sweden)

    Lazarević Mihailo P.

    2013-01-01

    Full Text Available In this paper, the applications of biologically inspired modeling and control of (biomechanical (nonredundant mechanisms are presented, as well as newly obtained results of author in mechanics which are based on using fractional calculus. First, it is proposed to use biological analog-synergy due to existence of invariant features in the execution of functional motion. Second, the model of (biomechanical system may be obtained using another biological concept called distributed positioning (DP, which is based on the inertial properties and actuation of joints of considered mechanical system. In addition, it is proposed to use other biological principles such as: principle of minimum interaction, which takes a main role in hierarchical structure of control and self-adjusting principle (introduce local positive/negative feedback on control with great amplifying, which allows efficiently realization of control based on iterative natural learning. Also, new, recently obtained results of the author in the fields of stability, electroviscoelasticity, and control theory are presented which are based on using fractional calculus (FC. [Projekat Ministarstva nauke Republike Srbije, br. 35006

  1. Mechanisms and neuronal networks involved in reactive and proactive cognitive control of interference in working memory.

    Science.gov (United States)

    Irlbacher, Kerstin; Kraft, Antje; Kehrer, Stefanie; Brandt, Stephan A

    2014-10-01

    Cognitive control can be reactive or proactive in nature. Reactive control mechanisms, which support the resolution of interference, start after its onset. Conversely, proactive control involves the anticipation and prevention of interference prior to its occurrence. The interrelation of both types of cognitive control is currently under debate: Are they mediated by different neuronal networks? Or are there neuronal structures that have the potential to act in a proactive as well as in a reactive manner? This review illustrates the way in which integrating knowledge gathered from behavioral studies, functional imaging, and human electroencephalography proves useful in answering these questions. We focus on studies that investigate interference resolution at the level of working memory representations. In summary, different mechanisms are instrumental in supporting reactive and proactive control. Distinct neuronal networks are involved, though some brain regions, especially pre-SMA, possess functions that are relevant to both control modes. Therefore, activation of these brain areas could be observed in reactive, as well as proactive control, but at different times during information processing. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Decoherence control mechanisms of a charged magneto-oscillator in contact with different environments

    Science.gov (United States)

    Rajesh, Asam; Bandyopadhyay, Malay; Jayannavar, Arun M.

    2017-12-01

    In this work, we consider two different techniques based on reservoir engineering process and quantum Zeno control method to analyze the decoherence control mechanism of a charged magneto-oscillator in contact with different type of environment. Our analysis reveals that both the control mechanisms are very much sensitive on the details of different environmental spectrum (J (ω)), and also on different system and reservoir parameters, e.g., external magnetic field (rc), confinement length (r0), temperature (T), cut-off frequency of reservoir spectrum (ωcut), and measurement interval (τ). We also demonstrate the manipulation scheme of the continuous passage from decay suppression to decay acceleration by tuning the above mentioned system or reservoir parameters, e.g., rc, r0, T and τ.

  3. Summary of the control-drive-mechanism design and performance for LWBR (LWBR Development Program)

    International Nuclear Information System (INIS)

    Yarnall, F.

    1983-01-01

    Control Drive Mechanisms (CDM) are used in the Light Water Breeder reactor to position Movable Fuel Assemblies weighing in excess of one ton each for purposes of reactivity control. These mechanisms are the first of a kind designed for loads of that magnitude. This report presents a summary of the design and performance of the CDM and includes discussions of the principles of operation, unique design features, and fabrication methods of this large, high load capacity CDM. The extensive design acceptance test program and the Shippingport plant periodic testing are summrized as are lessons learned during assembly of the CDM's to the reactor. These CDM's operated successfully to control the light water breeder core at the Shippingport Station from initial criticality in August 1977 to the final shutdown in October 1982. All test and operative data were within expected bands

  4. Mechanisms for the control of two-mode transient stimulated Raman scattering in liquids

    International Nuclear Information System (INIS)

    Spanner, Michael; Brumer, Paul

    2006-01-01

    Recent adaptive feedback control experiments demonstrated control of transient (i.e. nonimpulsive) Stokes emission from two closely spaced Raman-active modes in liquid methanol [e.g., B. J. Pearson et al., Phys. Rev. A 63, 063412 (2001)]. Optimally shaped pulses were found that selectively excited one of the two Stokes lines alone, optimized emission from both modes together, or completely suppressed all Stokes emission. Here, two general control mechanisms capable of affecting the ratio of intensities of the Stokes lines are identified. The first is operational when the duration of the pump pulse (t p ) is on the order of the collisional dephasing time (t d ). The ratio of the peak heights of the two Stokes lines can then be controlled by simply varying the duration and/or intensity of the pump pulse. The second operates when 1/t p is on the order of the energy separation of the two Raman modes, and hence when the two Raman modes are coupled due to overlapping nonlinear polarizations that drive the stimulated Raman scattering. In this regime, asymmetry in the spectral amplitudes within the pump pulse can control the asymmetry in the peak heights of the Stokes emission. Both these mechanisms have the same clear physical interpretation: shaping the pump pulse controls the nonlinear optical response of the medium, which in turn controls the stimulated Stokes emission, itself a χ (3) nonlinear effect. In neither mechanism does the ratio of peak heights in the Stokes spectrum reflect directly the ratio of excited-state populations associated with the two Raman modes, as was assumed in the experiments, nor does the control involve coherent quantum interference effects

  5. Role of hormones in controlling vascular differentiation and the mechanism of lateral root initiation.

    Science.gov (United States)

    Aloni, Roni

    2013-11-01

    The vascular system in plants is induced and controlled by streams of inductive hormonal signals. Auxin produced in young leaves is the primary controlling signal in vascular differentiation. Its polar and non-polar transport pathways and major controlling mechanisms are clarified. Ethylene produced in differentiating protoxylem vessels is the signal that triggers lateral root initiation, while tumor-induced ethylene is a limiting and controlling factor of crown gall development and its vascular differentiation. Gibberellin produced in mature leaves moves non-polarly and promotes elongation, regulates cambium activity and induces long fibers. Cytokinin from the root cap moves upward to promote cambial activity and stimulate shoot growth and branching, while strigolactone from the root inhibits branching. Furthermore, the role of the hormonal signals in controlling the type of differentiating vascular elements and gradients of conduit size and density, and how they regulate plant adaptation and have shaped wood evolution are elucidated.

  6. Laboratory implementation of quantum-control-mechanism identification through Hamiltonian encoding and observable decoding

    International Nuclear Information System (INIS)

    Rey-de-Castro, R.; Rabitz, H.

    2010-01-01

    We report on the laboratory implementation of quantum-control-mechanism identification through Hamiltonian encoding and observable decoding (HE-OD). Over a sequence of experiments, HE-OD introduces a special encoded signature into the components of a previously determined control field expressed in a chosen representation. The outcome appears as a modulated signal in the controlled system observable. Decoding the modulated signal identifies the hierarchy of correlations between components of the control field in a particular representation. In cases where the initial quantum state and observable operator are fully known, then HE-OD can also identify the transition amplitudes of the various Dyson expansion orders contributing to the controlled dynamics. The basic principles of HE-OD are illustrated for second harmonic generation when the components of the field representation are simply taken as the pixels in the pulse shaper. The outcome of HE-OD agrees well with simulations, verifying the concept.

  7. FUZZY LOGIC BASED ADAPTATION MECHANISM FOR ADAPTIVE LUENBERGER OBSERVER SENSORLESS DIRECT TORQUE CONTROL OF INDUCTION MOTOR

    Directory of Open Access Journals (Sweden)

    A. BENNASSAR

    2016-01-01

    Full Text Available Many industrial applications require high performance speed sensorless operation and demand new control methods in order to obtain fast dynamic response and insensitive to external disturbances. The current research aims to present the performance of the sensorless direct torque control (DTC of an induction motor (IM using adaptive Luenberger observer (ALO with fuzzy logic controller (FLC for adaptation mechanism. The rotor speed is regulated by proportional integral (PI anti-windup controller. The proposed strategy is directed to reduce the ripple on the torque and the flux. Numerical simulation results show the good performance and effectiveness of the proposed sensorless control for different references of the speed even both low and high speeds.

  8. Neuromuscular Control Mechanisms During Single-Leg Jump Landing in Subacute Ankle Sprain Patients: A Case Control Study.

    Science.gov (United States)

    Allet, Lara; Zumstein, Franziska; Eichelberger, Patric; Armand, Stéphane; Punt, Ilona M

    2017-03-01

    Optimal neuromuscular control mechanisms are essential for preparing, maintaining, and restoring functional joint stability during jump landing and to prevent ankle injuries. In subacute ankle sprain patients, neither muscle activity nor kinematics during jump landing has previously been assessed. To compare neuromuscular control mechanisms and kinematics between subacute ankle sprain patients and healthy persons before and during the initial contact phase of a 25-cm single-leg jump. Case-control study. University hospital. Fifteen patients with grade I or II acute ankle sprains were followed up after 4 weeks of conservative management not involving physical therapy. Subjects performed alternately 3 single-leg forward jumps of 25 cm (toe-to-heel distance) barefoot. Their results were compared with the data of 15 healthy subjects. Electromyographic (EMG) activity of the musculus (m.) gastrocnemius lateralis, m. tibialis anterior, and m. peroneus longus as well as kinematics for ankle, knee, and hip joint were recorded for pre-initial contact (IC) phase, post-initial contact phase, and reflex-induced phase. The results showed that EMG activity of the 3 muscles did not differ between ankle sprain patients (n = 15) and healthy persons (n = 15) for any of the analyzed time intervals (all P > .05). However, during the pre-IC phase, ankle sprain patients presented less plantar flexion, as well as during the post-IC phase after jump landing, compared to healthy persons (P ankle joint can lead to neuromuscular control mechanism disturbances through which functional instability might arise. III. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  9. [Likeness between respiratory responses on CO2 in conditions of natural breathing and voluntary-controlled mechanical ventilation].

    Science.gov (United States)

    Pogodin, M A; Granstrem, M P; Dimitrienko, A I

    2007-04-01

    We did Read CO2 rebreathing tests in 8 adult males. Both at natural breathing, and at self-controlled mechanical ventilation, volunteers increased ventilation proportionally to growth end-tidal PCO2. Inside individual distinctions of responses to CO2 during controlled mechanical ventilation are result of the voluntary motor control.

  10. Experience feedback of operational events of the control rod assembly and its drive mechanism in nuclear power plants

    International Nuclear Information System (INIS)

    Zhou Hong; Xiao Zhi; Tao Shusheng; Zheng Lixin; Chen Zhaolin

    2013-01-01

    Seventeen operational events of the control rod assembly and its drive mechanism are collected from 1992 to 2012 important nuclear operational events and feedback in referred nuclear power plants. After investigated and classified, several important issues, such as the impact of control rod swell and fuel assembly distortion, control rod drive mechanism leakage, and the control system reliability of control rod, are emphatically analyzed. Some suggestions of experience feedback are proposed. (authors)

  11. Polar red-emitting rhodamine dyes with reactive groups: synthesis, photophysical properties, and two-color STED nanoscopy applications.

    Science.gov (United States)

    Kolmakov, Kirill; Wurm, Christian A; Meineke, Dirk N H; Göttfert, Fabian; Boyarskiy, Vadim P; Belov, Vladimir N; Hell, Stefan W

    2014-01-03

    The synthesis, reactivity, and photophysical properties of new rhodamines with intense red fluorescence, two polar residues (hydroxyls, primary phosphates, or sulfonic acid groups), and improved hydrolytic stability of the amino-reactive sites (NHS esters or mixed N-succinimidyl carbonates) are reported. All fluorophores contain an N-alkyl-1,2-dihydro-2,2,4-trimethylquinoline fragment, and most of them bear a fully substituted tetrafluoro phenyl ring with a secondary carboxamide group. The absorption and emission maxima in water are in the range of 635-639 and 655-659 nm, respectively. A vastly simplified approach to red-emitting rhodamines with two phosphate groups that are compatible with diverse functional linkers was developed. As an example, a phosphorylated dye with an azide residue was prepared and was used in a click reaction with a strained alkyne bearing an N-hydroxysuccinimid (NHS) ester group. This method bypasses the undesired activation of phosphate groups, and gives an amphiphilic amino-reactive dye, the solubility and distribution of which between aqueous and organic phases can be controlled by varying the pH. The presence of two hydroxyl groups and a phenyl ring with two carboxyl residues in the dyes with another substitution pattern is sufficient for providing the hydrophilic properties. Selective formation of a mono-N-hydroxysuccinimidyl ester from 5-carboxy isomer of this rhodamine is reported. The fluorescence quantum yields varied from 58 to 92% for free fluorophores, and amounted to 18-64% for antibody conjugates in aqueous buffers. The brightness and photostability of these fluorophores facilitated two-color stimulated emission depletion (STED) fluorescence nanoscopy of biological samples with high contrast and minimal background. Selecting a pair of fluorophores with absorption/emission bands at 579/609 and 635/655 nm enabled two-color channels with low cross-talk and negligible background at approximately 40 nm resolution. Copyright

  12. Control system of executive mechanisms of a spectrometer on the IBR-2 reactor as a modern local network of controllers CAN

    International Nuclear Information System (INIS)

    Zhuravlev, V.V.; Kirillov, A.S.; Petukhova, T.B.; Sirotin, A.P.

    2007-01-01

    Controllers SMC-32 and SMC-32-CAN as elements of control systems of executive mechanisms of the IBR-2 spectrometers are submitted. The controllers provide management of executive mechanisms of spectrometers on the consecutive communication line RS232, RS422 (SMC-32, SMC-32-CAN), and on the local network CAN (SMC-32-CAN). The control systems of the executive mechanisms are easily modernized due to connection of additional elements of the local network CAN. Dynamic characteristics of the spectrometers' executive mechanisms are essentially improved. For example, it has been possible to increase the rotation frequency of the step motor DSHI-200 up to 10000 pps. (author)

  13. Development of a 3-D simulation analysis system for PWR control rod drive mechanism

    International Nuclear Information System (INIS)

    Tanaka, Akio; Futahashi, Kensuke; Takanabe, Kiyoshi; Kurimura, Chikara; Kato, Jungo; Hara, Hidekiyo

    2008-01-01

    A 3-D virtual analysis system to analyze the motion of control rod drive mechanism (CRDM) was developed. The analysis system consists of a 3-D model established as per the actual dimensions and interfaces of CRDM parts and a routine to calculate the forces acting on the mechanism, and was verified by mock-up test using the same equipment as the actual product. The analysis system is useful for functional evaluation in maintenance or to factor out root causes in the case of malfunction of CRDM

  14. Understanding the mechanism of nanotube synthesis for controlled production of specific (n,m) structures

    Energy Technology Data Exchange (ETDEWEB)

    Resasco, Daniel E.

    2010-02-11

    This report shows the extensive research on the mechanism responsible for the formation of single walled carbon nanotubes in order to get control over their structural parameters (diameter and chirality). Catalyst formulations, pre-treatment conditions, and reaction conditions are described in detail as well as mechanisms to produce nanotubes structures of specific arrays (vertical forest, nanotube pillars). Applications of SWNT in different fields are also described in this report. In relation to this project five students have graduated (3 PhD and 2 MS) and 35 papers have been published.

  15. A time-based admission control mechanism for IEEE 802.11 ad Hoc networks

    OpenAIRE

    Costa, Luís Henrique M. K.; Cerveira, Carlos Rodrigo

    2006-01-01

    This paper presents a time-based admission control mechanism (TAC) for IEEE 802.11 ad hoc networks. The proposed mechanism was adapted to the QoS AODV routing protocol, which takes the quality of service requirements of the data flow into account in the route discovery process. TAC-AODV estimates the idle time of the physical medium based on the frames listened. The incoming traffic is admitted according to the offered load as well as the intra-flow interference, calculated based on the numbe...

  16. Field and Laboratory Testing of Approaches to Smart Whole-House Mechanical Ventilation Control

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Eric [Florida Solar Energy Center, Cocoa, FL (United States); Fenaughty, Karen [Florida Solar Energy Center, Cocoa, FL (United States); Parker, Danny [Florida Solar Energy Center, Cocoa, FL (United States); Lubliner, Michael [Washington State Univ., Pullman, WA (United States); Howard, Luke [Washington State Univ., Pullman, WA (United States)

    2018-01-15

    Whole-house mechanical ventilation is a critical component to a comprehensive strategy for good indoor air quality (IAQ). However, due to lack of integration with standard heating and cooling systems, and perceptions from a portion of the homebuilding industry about risks related to increased energy use, increased cost, and decreased comfort, voluntary and code-required adoption varies amongst regions. Smart ventilation controls (SVC) balance energy consumption, comfort, and IAQ by optimizing mechanical ventilation operation to reduce the heating and/or cooling loads, improve management of indoor moisture, and maintain IAQ equivalence according to ASHRAE 62.2.

  17. Field and Laboratory Testing of Approaches to Smart Whole-House Mechanical Ventilation Control

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Eric [Florida Solar Energy Center, Cocoa, FL (United States); Fenaughty, Karen [Florida Solar Energy Center, Cocoa, FL (United States); Parker, Danny [Florida Solar Energy Center, Cocoa, FL (United States); Lubiner, Michael [Washington State Univ., Pullman, WA (United States); Howard, Luke [Washington State Univ., Pullman, WA (United States)

    2018-01-29

    Whole-house mechanical ventilation is a critical component to a comprehensive strategy for good indoor air quality (IAQ). However, due to lack of integration with standard heating and cooling systems, and perceptions from a portion of the homebuilding industry about risks related to increased energy use, increased cost, and decreased comfort, voluntary and code-required adoption varies among regions. Smart ventilation controls (SVC) balance energy consumption, comfort, and IAQ by optimizing mechanical ventilation operation to reduce the heating and/or cooling loads, improve management of indoor moisture, and maintain IAQ equivalence according to ASHRAE 62.2.

  18. Invited review article: high-speed flexure-guided nanopositioning: mechanical design and control issues.

    Science.gov (United States)

    Yong, Y K; Moheimani, S O R; Kenton, B J; Leang, K K

    2012-12-01

    Recent interest in high-speed scanning probe microscopy for high-throughput applications including video-rate atomic force microscopy and probe-based nanofabrication has sparked attention on the development of high-bandwidth flexure-guided nanopositioning systems (nanopositioners). Such nanopositioners are designed to move samples with sub-nanometer resolution with positioning bandwidth in the kilohertz range. State-of-the-art designs incorporate uniquely designed flexure mechanisms driven by compact and stiff piezoelectric actuators. This paper surveys key advances in mechanical design and control of dynamic effects and nonlinearities, in the context of high-speed nanopositioning. Future challenges and research topics are also discussed.

  19. A federated capability-based access control mechanism for internet of things (IoTs)

    Science.gov (United States)

    Xu, Ronghua; Chen, Yu; Blasch, Erik; Chen, Genshe

    2018-05-01

    The prevalence of Internet of Things (IoTs) allows heterogeneous embedded smart devices to collaboratively provide intelligent services with or without human intervention. While leveraging the large-scale IoT-based applications like Smart Gird and Smart Cities, IoT also incurs more concerns on privacy and security. Among the top security challenges that IoTs face is that access authorization is critical in resource and information protection over IoTs. Traditional access control approaches, like Access Control Lists (ACL), Role-based Access Control (RBAC) and Attribute-based Access Control (ABAC), are not able to provide a scalable, manageable and efficient mechanisms to meet requirement of IoT systems. The extraordinary large number of nodes, heterogeneity as well as dynamicity, necessitate more fine-grained, lightweight mechanisms for IoT devices. In this paper, a federated capability-based access control (FedCAC) framework is proposed to enable an effective access control processes to devices, services and information in large scale IoT systems. The federated capability delegation mechanism, based on a propagation tree, is illustrated for access permission propagation. An identity-based capability token management strategy is presented, which involves registering, propagation and revocation of the access authorization. Through delegating centralized authorization decision-making policy to local domain delegator, the access authorization process is locally conducted on the service provider that integrates situational awareness (SAW) and customized contextual conditions. Implemented and tested on both resources-constrained devices, like smart sensors and Raspberry PI, and non-resource-constrained devices, like laptops and smart phones, our experimental results demonstrate the feasibility of the proposed FedCAC approach to offer a scalable, lightweight and fine-grained access control solution to IoT systems connected to a system network.

  20. Spread and Control of Mobile Benign Worm Based on Two-Stage Repairing Mechanism

    Directory of Open Access Journals (Sweden)

    Meng Wang

    2014-01-01

    Full Text Available Both in traditional social network and in mobile network environment, the worm is a serious threat, and this threat is growing all the time. Mobile smartphones generally promote the development of mobile network. The traditional antivirus technologies have become powerless when facing mobile networks. The development of benign worms, especially active benign worms and passive benign worms, has become a new network security measure. In this paper, we focused on the spread of worm in mobile environment and proposed the benign worm control and repair mechanism. The control process of mobile benign worms is divided into two stages: the first stage is rapid repair control, which uses active benign worm to deal with malicious worm in the mobile network; when the network is relatively stable, it enters the second stage of postrepair and uses passive mode to optimize the environment for the purpose of controlling the mobile network. Considering whether the existence of benign worm, we simplified the model and analyzed the four situations. Finally, we use simulation to verify the model. This control mechanism for benign worm propagation is of guiding significance to control the network security.

  1. The comparison of manual and LabVIEW-based fuzzy control on mechanical ventilation.

    Science.gov (United States)

    Guler, Hasan; Ata, Fikret

    2014-09-01

    The aim of this article is to develop a knowledge-based therapy for management of rats with respiratory distress. A mechanical ventilator was designed to achieve this aim. The designed ventilator is called an intelligent mechanical ventilator since fuzzy logic was used to control the pneumatic equipment according to the rat's status. LabVIEW software was used to control all equipments in the ventilator prototype and to monitor respiratory variables in the experiment. The designed ventilator can be controlled both manually and by fuzzy logic. Eight female Wistar-Albino rats were used to test the designed ventilator and to show the effectiveness of fuzzy control over manual control on pressure control ventilation mode. The anesthetized rats were first ventilated for 20 min manually. After that time, they were ventilated for 20 min by fuzzy logic. Student's t-test for p < 0.05 was applied to the measured minimum, maximum and mean peak inspiration pressures to analyze the obtained results. The results show that there is no statistical difference in the rat's lung parameters before and after the experiments. It can be said that the designed ventilator and developed knowledge-based therapy support artificial respiration of living things successfully. © IMechE 2014.

  2. Indirect adaptive output feedback control of a biorobotic AUV using pectoral-like mechanical fins

    International Nuclear Information System (INIS)

    Naik, Mugdha S; Singh, Sahjendra N; Mittal, Rajat

    2009-01-01

    This paper treats the question of servoregulation of autonomous underwater vehicles (AUVs) in the yaw plane using pectoral-like mechanical fins. The fins attached to the vehicle have oscillatory swaying and yawing motion. The bias angle of the angular motion of the fin is used for the purpose of control. Of course, the design approach considered here is applicable to AUVs for other choices of oscillation patterns of the fins, which produce periodic forces and moments. It is assumed that the vehicle parameters, hydrodynamic coefficients, as well the fin forces and moments are unknown. For the trajectory control of the yaw angle, a sampled-data indirect adaptive control system using output (yaw angle) feedback is derived. The control system has a modular structure, which includes a parameter identifier and a stabilizer. For the control law derivation, an internal model of the exosignals (reference signal (constant or ramp) and constant disturbance) is included. Unlike the direct adaptive control scheme, the derived control law is applicable to minimum as well as nonminimum phase biorobotic AUVs (BAUVs). This is important, because for most of the fin locations on the vehicle, the model is a nonminimum phase. In the closed-loop system, the yaw angle trajectory tracking error converges to zero and the remaining state variables remain bounded. Simulation results are presented which show that the derived modular control system accomplishes precise set point yaw angle control and turning maneuvers in spite of the uncertainties in the system parameters using only yaw angle feedback

  3. Efficacy and possible mechanisms of perillaldehyde in control of Aspergillus niger causing grape decay.

    Science.gov (United States)

    Tian, Jun; Wang, Yanzhen; Zeng, Hong; Li, Zongyun; Zhang, Peng; Tessema, Akalate; Peng, Xue

    2015-06-02

    A variety of plant products have been recognized for their antifungal activity and recently have attracted food industry attention for their efficacy in controlling postharvest fungal decay of fruits. The antifungal activity of perillaldehyde (PAE) was evaluated against Aspergillus niger, a known cause of grape spoilage, and possible mechanisms were explored. PAE showed notable antifungal activity against A. niger, with a minimum inhibitory concentration (MIC) and a minimum fungicidal concentration (MFC) of 0.25 and 1 μl/ml, respectively. The accumulation of mycelial biomass was also inhibited by PAE in a dose-dependent manner, completely inhibiting mycelial growth at 1 μl/ml. In vivo data confirmed that the vapour treatment of grapes with various concentrations of PAE markedly improved control of A. niger and suppressed natural decay. Concentrations of PAE of 0.075 μl/ml air showed the greatest inhibition of fungal growth compared to the controls. Further experiments indicated that PAE activated a membrane-active mechanism that inhibits ergosterol synthesis, increases membrane permeability (as evidenced by extracellular pH and conductivity measurements), and disrupts membrane integrity, leading to cell death. Our findings suggest that this membrane-active mechanism makes PAE a promising potential antifungal agent for postharvest control of grape spoilage. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. On the Control of Social Approach-Avoidance Behavior: Neural and Endocrine Mechanisms.

    Science.gov (United States)

    Kaldewaij, Reinoud; Koch, Saskia B J; Volman, Inge; Toni, Ivan; Roelofs, Karin

    The ability to control our automatic action tendencies is crucial for adequate social interactions. Emotional events trigger automatic approach and avoidance tendencies. Although these actions may be generally adaptive, the capacity to override these emotional reactions may be key to flexible behavior during social interaction. The present chapter provides a review of the neuroendocrine mechanisms underlying this ability and their relation to social psychopathologies. Aberrant social behavior, such as observed in social anxiety or psychopathy, is marked by abnormalities in approach-avoidance tendencies and the ability to control them. Key neural regions involved in the regulation of approach-avoidance behavior are the amygdala, widely implicated in automatic emotional processing, and the anterior prefrontal cortex, which exerts control over the amygdala. Hormones, especially testosterone and cortisol, have been shown to affect approach-avoidance behavior and the associated neural mechanisms. The present chapter also discusses ways to directly influence social approach and avoidance behavior and will end with a research agenda to further advance this important research field. Control over approach-avoidance tendencies may serve as an exemplar of emotional action regulation and might have a great value in understanding the underlying mechanisms of the development of affective disorders.

  5. Modeling and Dynamic Simulation of the Adjust and Control System Mechanism for Reactor CAREM-25

    International Nuclear Information System (INIS)

    Larreteguy, A.E; Mazufri, C.M

    2000-01-01

    The adjust and control system mechanism, MSAC, is an advanced, and in some senses unique, hydromechanical device.The efforts in modeling this mechanism are aimed to: Get a deep understanding of the physical phenomena involved,Identify the set of parameters relevant to the dynamics of the system,Allow the numerical simulation of the system,Predict the behavior of the mechanism in conditions other than that obtainable within the range of operation of the experimental setup (CEM), and Help in defining the design of the CAPEM (loop for testing the mechanism under high pressure/high temperature conditions).Thanks to the close interaction between the mechanics, the experimenters, and the modelists that compose the MSAC task force, it has been possible to suggest improvements, not only in the design of the mechanism, but also in the design and the operation of the pulse generator (GDP) and the rest of the CEM.This effort has led to a design mature enough so as to be tested in a high-pressure loop

  6. Mechanisms controlling the impact of multi-year drought on mountain hydrology.

    Science.gov (United States)

    Bales, Roger C; Goulden, Michael L; Hunsaker, Carolyn T; Conklin, Martha H; Hartsough, Peter C; O'Geen, Anthony T; Hopmans, Jan W; Safeeq, Mohammad

    2018-01-12

    Mountain runoff ultimately reflects the difference between precipitation (P) and evapotranspiration (ET), as modulated by biogeophysical mechanisms that intensify or alleviate drought impacts. These modulating mechanisms are seldom measured and not fully understood. The impact of the warm 2012-15 California drought on the heavily instrumented Kings River basin provides an extraordinary opportunity to enumerate four mechanisms that controlled the impact of drought on mountain hydrology. Two mechanisms intensified the impact: (i) evaporative processes have first access to local precipitation, which decreased the fractional allocation of P to runoff in 2012-15 and reduced P-ET by 30% relative to previous years, and (ii) 2012-15 was 1 °C warmer than the previous decade, which increased ET relative to previous years and reduced P-ET by 5%. The other two mechanisms alleviated the impact: (iii) spatial heterogeneity and the continuing supply of runoff from higher elevations increased 2012-15 P-ET by 10% relative to that expected for a homogenous basin, and iv) drought-associated dieback and wildfire thinned the forest and decreased ET, which increased 2016 P-ET by 15%. These mechanisms are all important and may offset each other; analyses that neglect one or more will over or underestimate the impact of drought and warming on mountain runoff.

  7. A control strategy for electro-magneto-mechanical system based on virtual system model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Youn; Heo, Hoon [Dept. of Control and Instrumentation Engineering, Korea University, Seoul (Korea, Republic of); Yun, Young Min [TPC Mechatronics Co., Ltd., Incheon (Korea, Republic of)

    2016-09-15

    A new approach to the control of electro-magneto-mechanical system is proposed in this paper. Conventionally, these systems are controlled based on the Maxwell system model via an on-off or PID control technique, which displays acceptable performance in the low frequency region, but not in the high frequency region where position control performance is greatly degraded. In order to improve the performance, a newly developed virtual 2nd order system modeling technique, SSID, is adopted for a complex electro-magnetomechanical system in the study. This technique states that any unknown system exposed to a random disturbance with unknown intensity can be identified in terms of a virtual 2nd order system model via the inverse process of a certain stochastic analysis. As a typical hybrid system, a solenoid valve is used as the target electro-magneto-mechanical system to study the modeling of the virtual 2nd order system. In order to confirm the performance of the proposed control strategy, autotuning PID controller in PWM mode is utilized. Simulations based on the conventional Maxwell system model with control via the bang-bang, autotuning PID, and the proposed virtual 2nd order system model approaches are conducted using MATLAB Simulink. Performance of these three systems in the low and high frequency bands is also compared. The simulation results reveal that the control performance of the virtual 2nd order system model is much improved compared with that of the Maxwell system model under autotuning PID and bang-bang controls in both low and high frequency regions, where the error is drastically reduced to approximately 1/5 of the original value.

  8. Photochemistry and photophysics of the amino and imino tautomers of 1-methylcytosine: tautomerisation as a side product of the radiationless decay.

    Science.gov (United States)

    Li, Quansong; Blancafort, Lluís

    2013-08-01

    The photochemistry and photophysics of the amino-oxo (AO) and imino-oxo (IO) tautomers of 1-methylcytosine are investigated with ab initio calculations, using the CASPT2//CASSCF approach. Our aim is to rationalize recent experimental results which show that the AO tautomer has an excited state lifetime of about 1 ps, similar to cytosine (J.-W. Ho, H.-C. Yen, W.-K. Chou, C.-N. Weng, L.-H. Cheng, H.-Q. Shi, S.-H. Lai and P.-Y. Cheng, J. Phys. Chem. A, 2011, 115, 8406-8418), and that irradiation with wavelengths shorter than 308 nm induces the AO→IO tautomerization (I. Reva, M. J. Nowak, L. Lapinski and R. Fausto, J. Phys. Chem. B, 2012, 116, 5703-5710). For the canonical AO tautomer we find two analogous decay mechanisms to those described previously for cytosine, involving a conical intersection of ethylenic type and one where the amino group is bent out of plane. Decay through these intersections provides an unreactive return path to the AO ground state species. More importantly, we have identified new decay paths that lead from the two intersections to the trans-IO tautomer, without a barrier. These paths provide the possibility of forming the IO tautomer, presumably in small yields, as a side product of the radiationless decay. Thus, we have established for the first time computationally the mechanism of the UV-induced tautomerization, which is compatible with the well-established decay mechanism for cytosine. For the IO tautomer, we also find a mechanism for the excited state interconversion of the cis and trans forms and for efficient radiationless decay through a conical intersection where the imino group is perpendicular to the ring and bent out of the plane. These results are likely to be valid also for cytosine.

  9. Photo-physical properties enhancement of bare and core-shell quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Mumin, Md Abdul, E-mail: pcharpentier@eng.uwo.ca; Akhter, Kazi Farida, E-mail: pcharpentier@eng.uwo.ca; Charpentier, Paul A., E-mail: pcharpentier@eng.uwo.ca [Chemical and Biochemical Engineering, Western University, London Ontario (Canada)

    2014-03-31

    Semiconductor nanocrystals (NCs) (also known as quantum dots, QDs) have attracted immense attention for their size-tunable optical properties that makes them impressive candidates for solar cells, light emitting devices, lasers, as well as biomedical imaging. However monodispersity, high and consistent photoluminescence, photostability, and biocompatibility are still major challenges. This work focuses on optimizing the photophysical properties and biocompatibility of QDs by forming core-shell nanostructures and their encapsulation by a carrier. Highly luminescent CdS and CdS-ZnS core-shell QDs with 5 nm sizes were synthesized using a facile approach based on pyrolysis of the single molecule precursors. After capping the CdS QDs with a thin layer of ZnS to reduce toxicity, the photoluminescence and photostability of the core-shell QDs was significantly enhanced. To make both the bare and core/shell structure QDs more resistant against photochemical reactions, a mesoporous silica layer was grown on the QDs through a reverse microemulsion technique based on hydrophobic interaction. This encapsulation enhanced the quantum yield and photostability compared to the bare QDs by providing much stronger resistance to oxidation and Oswald ripening of QDs. Encapsulation also improved biocompatibility of QDs that was evaluated with human umbilical vein endothelial cell lines (HUVEC)

  10. Novel asymmetrical pyrene derivatives as light emitting materials: Synthesis and photophysics

    International Nuclear Information System (INIS)

    Li Yang; Wang Dong; Wang Lei; Li Zhengqiang; Cui Qing; Zhang Haiquan; Yang Huai

    2012-01-01

    A series of novel substituted pyrene derivatives with asymmetrical groups have been successfully synthesized in excellent yield. Structures of the asymmetrical compound were fully characterized by 1 H-NMR, IR spectroscopy and mass spectrometry. By introducing ethynyl functions to pyrene, we obtained highly efficient blue and green light emitting materials. It has been demonstrated that the emission characteristics of pyrene derivatives have been bathochromatically tuned in the visible region by extending the π-conjugation. The photophysical properties of these compounds were carefully examined in different organic solvents and different concentrations. The electrochemical properties and geometrical electronic structures of the new pyrene derivatives have been investigated by cyclic voltammograms and density functional theory (DFT) calculations. - Highlights: ► It is the first research about asymmetrial pyrene derivatives as highly efficient light emitting materials. ► The solvatochromism and concentration effect of the new compounds have been discussed. ► Furthermore, the electrochemical properties and geometrical electronic structures were also investigated in this paper.

  11. Synthesis, photophysical and photochemical properties of zinc phthalocyanines bearing fluoro-functionalized substituents

    Energy Technology Data Exchange (ETDEWEB)

    Aktaş, Ayşe [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Pişkin, Mehmet [Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadikoy-Istanbul (Turkey); Durmuş, Mahmut [Gebze Institute of Technology, Department of Chemistry, PO Box 141, Gebze 41400, Kocaeli (Turkey); Bıyıklıoğlu, Zekeriya, E-mail: zekeriya_61@yahoo.com [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2014-01-15

    In this study, the synthesis of phthalonitrile derivatives bearing fluoro-functionalized groups and their peripherally-tetra substituted zinc phthalocyanine complexes were reported. The phthalonitrile derivatives 2a–5a were prepared by nucleophilic substitution of 4-nitrophthalonitrile with 2-[3-(trifluoromethyl)phenoxy]ethanol, 2-{2-[3-(trifluoromethyl) phenoxy]ethoxy}ethanol, 2-(2,3,5,6-tetrafluorophenoxy)ethanol, 2-[2-(2,3,5,6-tetrafluorophenoxy)ethoxy]ethanol, respectively. Zinc phthalocyanines bearing fluoro-functionalized groups (2b–5b) were obtained from the corresponding phthalonitrile derivatives. The newly synthesized phthalocyanines displayed good solubility in organic solvents such as chloroform (CHCl{sub 3}), dichloromethane (DCM), tetrahydrofuran (THF), toluene, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). On the other hand, the singlet oxygen, photodegradation, fluorescence quantum yields and fluorescence lifetime of these complexes were determined in DMSO. The effects of the substitution with fluoro-functionalized groups on these parameters were also compared. -- Highlights: • Synthesis of peripherally substituted zinc phthalocyanines. • Photophysical and photochemical properties in DMSO for phthalocyanines. • Photodynamic therapy studies.

  12. Solvent Effect, Photochemical and Photophysical Properties of Phthalocyanines with Different Metallic Nuclei

    Directory of Open Access Journals (Sweden)

    Charles Biral Silva

    2017-12-01

    Full Text Available Photophysical and photochemical properties of lithium phthalocyanine (1, gallium(III phthalocyanine chloride (2, titanium(IV phthalocyanine dichloride (3 and iron(II phthalocyanine (4 were investigated in dimethyl sulfoxide (DMSO, tetrahydrofuran (THF and DMSO-THF mixtures. The influence of the central metal on these properties was analyzed according to solvent type, axial ligands and their paramagnetic and diamagnetic effect. Fluorescence lifetimes were recorded using a time correlated single photon counting setup (TCSPC technique. In order to demonstrate the generation of reactive oxygen species under light irradiation, the indirect method (applying 1,3-diphenylisobenzofuran (DPBF as chemical suppressor and the direct method (analyzing the phosphorescence decay curves of singlete oxygen at 1270 nm were employed. Compounds 1, 2 and 3 showed a monomeric behavior in all media while compound 4 presented low aggregation in DMSO, but a very pronounced aggregation behavior in THF. Steady-state fluorescence anisotropy was compared with emission spectra and complex 4 presented values beyond the expected limits. DOI: http://dx.doi.org/10.17807/orbital.v9i5.1047 

  13. Synthesis and photophysical properties of fluorescence sensing diester-terminated 1,8-naphthalimide

    International Nuclear Information System (INIS)

    Bojinov, N. I. Georgiev. V. B.

    2011-01-01

    Full text: The immediate detection and determination of environmental pollutants have been gaining particular importance. In recent years, extensive research has been carried out on fluorescent organic compounds whose photophysical properties are sensitive to environmental changes. Such interest is due to the possibility of tailoring the design of molecular devices for environmental pollution caused by heavy and transition metal ions. Photoinduced electron transfer (PET) using the 'fluorophore-spacer-receptor' format, developed by de Silva, is one of the most popular approaches to the design of fluorescent sensors.; This work reports the synthesis and sensor activity of a 1,8-naphthalimide sensor based on the 'fluorophore-spacer-receptor' format. The diester-terminated 1,8-naphthalimide was found to display sensitive fluorescence signal amplification over a wide pH scale, which has been ascribed to a photoinduced electron transfer from the tertiary amine receptor to the fluorophore. From the changes in the fluorescence intensity, a pKa value of 4.42 was determined, making the synthesized compound of potential use as pH chemosensing material.; In addition, the ability to detect ions has been evaluated in DMF by monitoring the quenching of the fluorescence intensity. Different ions have been tested: Zn 2+ , Ni 2+ , Pb 2+ , Co 2+ , Cu 2+ , and Fe 3+ for this purpose. The results have clearly shown that only Fe 3+ could be efficiently detected

  14. Synthesis, photophysical and photochemical properties of zinc phthalocyanines bearing fluoro-functionalized substituents

    International Nuclear Information System (INIS)

    Aktaş, Ayşe; Pişkin, Mehmet; Durmuş, Mahmut; Bıyıklıoğlu, Zekeriya

    2014-01-01

    In this study, the synthesis of phthalonitrile derivatives bearing fluoro-functionalized groups and their peripherally-tetra substituted zinc phthalocyanine complexes were reported. The phthalonitrile derivatives 2a–5a were prepared by nucleophilic substitution of 4-nitrophthalonitrile with 2-[3-(trifluoromethyl)phenoxy]ethanol, 2-{2-[3-(trifluoromethyl) phenoxy]ethoxy}ethanol, 2-(2,3,5,6-tetrafluorophenoxy)ethanol, 2-[2-(2,3,5,6-tetrafluorophenoxy)ethoxy]ethanol, respectively. Zinc phthalocyanines bearing fluoro-functionalized groups (2b–5b) were obtained from the corresponding phthalonitrile derivatives. The newly synthesized phthalocyanines displayed good solubility in organic solvents such as chloroform (CHCl 3 ), dichloromethane (DCM), tetrahydrofuran (THF), toluene, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). On the other hand, the singlet oxygen, photodegradation, fluorescence quantum yields and fluorescence lifetime of these complexes were determined in DMSO. The effects of the substitution with fluoro-functionalized groups on these parameters were also compared. -- Highlights: • Synthesis of peripherally substituted zinc phthalocyanines. • Photophysical and photochemical properties in DMSO for phthalocyanines. • Photodynamic therapy studies

  15. Biosorption of arsenic from groundwater using Vallisneria gigantea plants. Kinetics, equilibrium and photophysical considerations.

    Science.gov (United States)

    Iriel, Analia; Lagorio, M Gabriela; Fernández Cirelli, Alicia

    2015-11-01

    Arsenic (V) uptake from groundwater by using Vallisneria gigantea plants was studied using batch experiments. Reflectance and fluorescence of intact plants were investigated and changes in photophysical properties following arsenic absorption were reported. Good correlations have been found between arsenic concentration in groundwater and parameters derived from reflectance and fluorescence measurements. This system reached its equilibrium after seven days when the removal quantities were strongly dependent on the initial arsenic concentration. Interestingly, Vallisneria plants were able to accumulate from 100 to 600 mg As kg(-1) in roots and fronds although the translocation factors were low (0.6-1.6). Kinetic data for biosorption process followed a first-order law. At low arsenic concentrations the uptake in plants was governed by diffusion aspects. Langmuir, Freundlich and Dubinin-Radushkevich models were applied and results demonstrated that arsenic uptake was better described by the Langmuir model. As a final remark we concluded that a plant of this species should be able to remove 1mg As per week. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Impact of Nonfullerene Acceptor Core Structure on the Photophysics and Efficiency of Polymer Solar Cells

    KAUST Repository

    Alamoudi, Maha

    2018-03-02

    Small-molecule “nonfullerene” acceptors are promising alternatives to fullerene (PC61/71BM) derivatives often used in bulk heterojunction (BHJ) organic solar cells; yet, the efficiency-limiting processes and their dependence on the acceptor structure are not clearly understood. Here, we investigate the impact of the acceptor core structure (cyclopenta-[2,1-b:3,4-b′]dithiophene (CDT) versus indacenodithiophene (IDTT)) of malononitrile (BM)-terminated acceptors, namely CDTBM and IDTTBM, on the photophysical characteristics of BHJ solar cells. Using PCE10 as donor polymer, the IDTT-based acceptor achieves power conversion efficiencies (8.4%) that are higher than those of the CDT-based acceptor (5.6%) because of a concurrent increase in short-circuit current and open-circuit voltage. Using (ultra)fast transient spectroscopy we demonstrate that reduced geminate recombination in PCE10:IDTTBM blends is the reason for the difference in short-circuit currents. External quantum efficiency measurements indicate that the higher energy of interfacial charge-transfer states observed for the IDTT-based acceptor blends is the origin of the higher open-circuit voltage.

  17. Photophysics of size-selected InP nanocrystals: Exciton recombination kinetics

    International Nuclear Information System (INIS)

    Kim, S.; Wolters, R.H.; Heath, J.R.

    1996-01-01

    We report here on the size-dependent kinetics of exciton recombination in a III endash V quantum dot system, InP. The measurements reported include various frequency dependent quantum yields as a function of temperature, frequency dependent luminescence decay curves, and time-gated emission spectra. This data is fit to a three-state quantum model which has been previously utilized to explain photophysical phenomena in II endash VI quantum dots. The initial photoexcitation is assumed to place an electron in a (delocalized) bulk conduction band state. Activation barriers for trapping and detrapping of the electron to surface states, as well as activation barriers for surface-state radiationless relaxation processes are measured as a function of particle size. The energy barrier to detrapping is found to be the major factor limiting room temperature band-edge luminescence. This barrier increases with decreasing particle size. For 30 A particles, this barrier is found to be greater than 6 kJ/mol emdash a barrier which is more than an order of magnitude larger than that previously found for 32 A CdS nanocrystals. copyright 1996 American Institute of Physics

  18. Synthesis and photo-physical properties of fluorescent 1,3,5-triazine styryl derivatives

    Directory of Open Access Journals (Sweden)

    Padalkar Vikas S

    2011-12-01

    Full Text Available Abstract Background Organic fluorophore contains well-defined D-π-A (Donor-π system-Acceptor push-pull system have wide application in the field of NLO, OLED and high tech application. Electron donor diphenyl, triphenyl and carbazole conjugated with electron acceptor terminal through π-system were reported recently for high-tech applications. N,N-Dialkyl substituted 1,3,5-triazine also acts as donor keeping this idea in mind we developed D-π-A styryl dyes. Results Novel "Y"-shaped acceptor-π-donor-π-acceptor type of compounds were synthesized from 4,4'-((6-(4-(diethylaminophenyl-1,3,5-triazine-2,4diylbis(oxy dibenzaldehyde (DIPOD as electron donors and different active methylene compounds as electron acceptors by conventional Knoevenagel condensation reaction. Their photophysical and thermal properties were investigated. Conclusion It was found that the strong electron acceptor-donor chromophoric system of these compounds showed high Stoke's shift and excellent thermal stability. Compounds showed positive solvatofluorism behavior from nonpolar to polar solvent. All compounds have good thermal stability.

  19. Photophysical characterization of cumarin-doped poly (lactic acid) microparticles and visualization of the biodistribution

    International Nuclear Information System (INIS)

    Abe, Shigeaki; Kiba, Takayuki; Hosokawa, Kiyotada; Nitobe, Satoru; Hirota, Takashi; Kobayashi, Hirohisa; Akasaka, Tsukasa; Uo, Motohiro; Kuboki, Yoshinori; Sato, Shin-Ichiro; Watari, Fumio; Rosca, Iosif D.

    2010-01-01

    We prepared fluorescent coumarin dye-doped poly (acrylic acid) microparticles, which are well known as a biodegradable polyester, and the photophysical properties were characterized by scanning electron microscope, atomic force microscope and spectroscopic investigation. Spherical particles with diameters ranging from 0.5 to a few μm were obtained. Based on spectroscopic investigation, the internal environment was close to that of a polar solvent such as methanol, and the dyes were dispersed without aggregation inside the particles. The obtained particles were administered to a mouse through the tail vein, and the biodistribution was then observed after some organs were excited at 1-day and 1-week post-injection. The particles were accumulated in the organs, especially in the lung and spleen. After injection, the particles were trapped temporally in the lung, and then seemed to be transported to other organs by blood circulation. This tendency is similar to the biodistribution of TiO 2 microparticles that we have reported previously.

  20. Novel nonplanar triphenylamine-centered oligofluorenes: Synthesis, thermal, photophysical and electrochemical properties

    International Nuclear Information System (INIS)

    Zhang Yujian; Ouyang Mi; Yu Chunhui; Hu Bin; Lou Qianping; Zhang Cheng

    2011-01-01

    A series of fluorene derivatives containing a triphenylamine (TPA) derivative core and two oligofluorene peripheries was effectively synthesized. These compounds are fluorescent and emission color ranges from blue to red. The spiro-skeleton molecular structure leads to excellent glass transition temperatures and weak intermolecular interactions. Simultaneously, novel nonplanar triphenylamine-centered oligofluorenes solve the spectral stability problem and hole-injection issue for fluorene-based materials. The photophysical properties of 6 and 7 are investigated in solvents with different polarities, which reveal the existence of the Charge Transfer (CT) excited-state in these molecules. - Highlights: → Novel nonplanar oligofluorenes consisting of triphenylamine (TPA) derivatives as the core and oligofluorenes as the peripheries were facilely prepared via CF 3 SO 3 H-promoted Friedel-Crafts and Suzuki cross-coupling reactions. → These as-prepared compounds effectively solve the spectral stability problem and hole-injection issue for fluorene-based materials. → The ability of hole-injection and emission color could be fine tuned by R substituent at the C4 position of TPA.