WorldWideScience

Sample records for push pull trains

  1. PushPull++

    KAUST Repository

    Lipp, Markus

    2014-07-27

    PushPull tools are implemented in most commercial 3D modeling suites. Their purpose is to intuitively transform a face, edge, or vertex, and then to adapt the polygonal mesh locally. However, previous approaches have limitations: Some allow adjustments only when adjacent faces are orthogonal; others support slanted surfaces but never create new details. Moreover, self-intersections and edge-collapses during editing are either ignored or work only partially for solid geometry. To overcome these limitations, we introduce the PushPull++ tool for rapid polygonal modeling. In our solution, we contribute novel methods for adaptive face insertion, adjacent face updates, edge collapse handling, and an intuitive user interface that automatically proposes useful drag directions. We show that PushPull++ reduces the complexity of common modeling tasks by up to an order of magnitude when compared with existing tools. Copyright © ACM.

  2. Push-pull farming systems.

    Science.gov (United States)

    Pickett, John A; Woodcock, Christine M; Midega, Charles A O; Khan, Zeyaur R

    2014-04-01

    Farming systems for pest control, based on the stimulo-deterrent diversionary strategy or push-pull system, have become an important target for sustainable intensification of food production. A prominent example is push-pull developed in sub-Saharan Africa using a combination of companion plants delivering semiochemicals, as plant secondary metabolites, for smallholder farming cereal production, initially against lepidopterous stem borers. Opportunities are being developed for other regions and farming ecosystems. New semiochemical tools and delivery systems, including GM, are being incorporated to exploit further opportunities for mainstream arable farming systems. By delivering the push and pull effects as secondary metabolites, for example, (E)-4,8-dimethyl-1,3,7-nonatriene repelling pests and attracting beneficial insects, problems of high volatility and instability are overcome and compounds are produced when and where required.

  3. Biomechanical study of the final push-pull in archery.

    Science.gov (United States)

    Leroyer, P; Van Hoecke, J; Helal, J N

    1993-02-01

    The purpose of this study was to analyse archery performance among eight archers of different abilities by means of displacement pull-hand measurements during the final push-pull phase of the shoot. The archers showed an irregular displacement negatively related to their technical level. Displacement signal analysis showed high power levels in both the 0-5 Hz and 8-12 Hz ranges. The latter peak corresponds to electromyographic tremor observed during a prolonged push-pull effort. The results are discussed in relation to some potentially helpful training procedures such as biofeedback and strength conditioning.

  4. Import-push or Export-pull?

    DEFF Research Database (Denmark)

    Jäkel, Ina Charlotte

    2014-01-01

    Does the selection effect of trade work solely through competition from imports, or does the export market further contribute to firm selection? This paper provides a re-interpretation of the different mechanisms in terms of selection on profitability - rather than productivity - and derives novel...... predictions regarding the export market and the role of product differentiation. Empirical results for a sample of Danish manufacturing industries confirm the import- "push" hypothesis as well as the export- "pull" hypothesis, but also reveal differences across industries. The selection effect of trade...... is mainly driven by the "import-push" if product differentiation is high, whereas it is driven by the "export-pull" if goods are homogeneous....

  5. Import-push or Export-pull?

    DEFF Research Database (Denmark)

    Jäkel, Ina Charlotte

    Does the selection effect of trade work solely through competition from imports, or does the export market further contribute to firm selection? This paper provides a re-interpretation of the different mechanisms in terms of selection on profitability - rather than productivity - and derives novel...... predictions regarding the export market and the role of product differentiation. Empirical results for a sample of Danish manufacturing industries confirm the import-"push" hypothesis as well as the export-"pull" hypothesis, but also reveal differences across industries. The selection effect of trade...... is mainly driven by the "import-push" if product differentiation is high, whereas it is driven by the "export-pull" if goods are homogeneous....

  6. Import-push or Export-pull?

    DEFF Research Database (Denmark)

    Jäkel, Ina Charlotte

    2014-01-01

    Does the selection effect of trade work solely through competition from imports, or does the export market further contribute to firm selection? This paper provides a re-interpretation of the different mechanisms in terms of selection on profitability - rather than productivity - and derives novel...... predictions regarding the export market and the role of product differentiation. Empirical results for a sample of Danish manufacturing industries confirm the import- "push" hypothesis as well as the export- "pull" hypothesis, but also reveal differences across industries. The selection effect of trade...

  7. On the Push-Pull Mobile Learning of Electric Welding

    Science.gov (United States)

    Chung, Chih-Chao; Dzan, Wei-Yuan; Cheng, Yuh-Ming; Lou, Shi-Jer

    2017-01-01

    This study aims to explore the learning effects and attitudes of students in the course electric welding practice in a university of science and technology to which the push-pull technology-based mobile learning system is applied. In this study, the push-pull technology is adopted to establish a mobile learning system and develop the Push-pull…

  8. Fast photo-processes in triazole-based push-pull systems

    NARCIS (Netherlands)

    Zoon, P.D.; van Stokkum, I.H.M.; Parent, M.; Mongin, O.; Blanchard-Desce, M.; Brouwer, A.M.

    2010-01-01

    Electron donor-acceptor compounds 1 (asymmetrical push-pull derivative) and 2 (symmetrical push-pull-push derivative) were studied in which one (push-pull) or two aniline units (push-pull-push) are connected to a biphenyl group via triazole linkers, made by "click" chemistry. Steady-state and time-r

  9. An asymmetry between pushing and pulling for crawling cells

    CERN Document Server

    Recho, Pierre

    2013-01-01

    Eukaryotic cells possess motility mechanisms allowing them not only to self-propel but also to exert forces on obstacles (to push) and to carry cargoes (to pull). To study the inherent asymmetry between active pushing and pulling we model a crawling acto-myosin cell extract as a 1D layer of active gel subjected to external forces. We show that pushing is controlled by protrusion and that the macroscopic signature of the protrusion dominated motility mechanism is concavity of the force velocity relation. Instead, pulling is driven by protrusion only at small values of the pulling force and it is replaced by contraction when the pulling force is sufficiently large. This leads to more complex convex-concave structure of the force velocity relation, in particular, competition between protrusion and contraction can produce negative mobility in a biologically relevant range. The model illustrates active readjustment of the force generating machinery in response to changes in the dipole structure of external forces....

  10. Push and pull strategies: applications for health care marketing.

    Science.gov (United States)

    Kingsley, B R

    1987-08-01

    As health care markets mature and expand, strategies available in other industries become useful. This article examines how traditional push-pull strategies apply to health care. Marketers using a push strategy recognize that the sale of their services or goods is dependent upon the endorsement of a middleman and promote their product through the middleman. Those using a pull strategy market directly to the consumer. In this article, the author outlines the advantages and disadvantages of using each strategy.

  11. Forearm posture and grip effects during push and pull tasks.

    Science.gov (United States)

    Di Domizio, Jennifer; Keir, Peter J

    2010-03-01

    Direction of loading and performance of multiple tasks have been shown to elevate muscle activity in the upper extremity. The purpose of this study was to evaluate the effects of gripping on muscle activity and applied force during pushing and pulling tasks with three forearm postures. Twelve volunteers performed five hand-based tasks in supinated, neutral and pronated forearm postures with the elbow at 90 degrees and upper arm vertical. All tasks were performed with the right (dominant) hand and included hand grip alone, push and pull with and without hand grip. Surface EMG from eight upper extremity muscles, hand grip force, tri-axial push and pull forces and wrist angles were recorded during the 10 s trials. The addition of a pull force to hand grip elevated activity in all forearm muscles (all p push with grip tasks, forearm extensor muscle activity tended to increase when compared with grip only while flexor activity tended to decrease. Forearm extensor muscle activity was higher with the forearm pronated compared with neutral and supinated postures during most isolated grip tasks and push or pull with grip tasks (all p push and pull forces could act to assist in creating grip force, forearm muscle activity generally decreased. These results provide strategies for reducing forearm muscle loading in the workplace. STATEMENT OF RELEVANCE: Tools and tasks designed to take advantage of coupling grip with push or pull actions may be beneficial in reducing stress and injury in the muscles of the forearm. These factors should be considered in assessing the workplace in terms of acute and cumulative loading.

  12. KOMPARASI SISTEM MANUFAKTUR PUSH DAN PULL MELALUI PENDEKATAN SIMULASI

    Directory of Open Access Journals (Sweden)

    Eric Wibisono

    2004-01-01

    Full Text Available Manufacturing systems that are often classified as push and pull often invite question: "How far do the differences between those two systems exist?" Many researches have been carried out but succinct answer to the above question is always difficult to reach. The difficulty roots from the variety of definition of the push and pull systems itself and also from the variety of complexity of a manufacturing system. This paper attempts to study the differences in performance between push and pull systems in a relatively simple model that consists of 4 serial processors with buffers located between these processors. Variations being modelled is on the setting of the system's load (high and low and the buffer size with performance being measured include machine utilization, number of outputs and mean flow time of jobs. The approach used is simulation using ProModel software as the tool. From the experiments it can be derived that buffer size turns out to be a very critical factor in system performance. Moreover, it is also proved that when the buffer size is large, push and pull systems do not differ significantly. Abstract in Bahasa Indonesia : Sistem manufaktur yang umumnya dikategorikan menjadi sistem push dan pull sering mengundang pertanyaan: "Seberapa jauh perbedaan dari kedua sistem tersebut ada?" Banyak penelitian telah dilakukan namun jawaban yang lugas atas pertanyaan tersebut sulit diperoleh. Kesulitan ini umumnya berakar dari beragamnya definisi sistem push dan pull itu sendiri serta variasi dari kompleksitas suatu sistem manufaktur. Makalah ini mencoba melihat perbedaan antara kinerja sistem push dan pull dalam suatu model sederhana yang terdiri dari 4 prosesor serial dengan buffer yang diletakkan di antara masing-masing prosesor tersebut. Variasi yang dilakukan adalah pada setting beban kerja sistem (padat dan ringan dan ukuran buffer dengan kinerja yang diukur adalah utilisasi mesin, jumlah output dan rata-rata waktu tinggal job

  13. The push-pull strategy for citrus psyllid control.

    Science.gov (United States)

    Yan, Huaxue; Zeng, Jiwu; Zhong, Guangyan

    2015-07-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the only natural vector of Candidatus Liberibacter asiaticus that causes citrus huanglongbing (HLB), a most destructive disease of citrus. Currently, no remedial therapy exists for the disease, and so effective control of ACP is very important in curbing the transmission of the disease. The push-pull strategy should be thoroughly explored as an approach to ACP management. This mini-review summarises the current progress towards more effective repellent and attractant chemicals through investigating known repellent and attractive plants. Interactions between ACP and its host plants are also addressed, with emphasis on the possible involvement of the host biochemicals in attracting the insect. Potential ways to increase the effectiveness of the pull-push strategy are briefly discussed. It is expected that the pull-push strategy will be gradually developed following more extensive research.

  14. Ultrabroadband pulse shaping with a push-pull deformable mirror.

    Science.gov (United States)

    Bonora, Stefano; Brida, Daniele; Villoresi, Paolo; Cerullo, Giulio

    2010-10-25

    We report the programmable pulse shaping of ultrabroadband pulses by the use of a novel design of electrostatic deformable mirror based on push pull technology. We shape few-optical pulses from near-IR and visible optical parametric amplifiers, and demonstrate strong-field control of excited state population transfer in a dye molecule.

  15. Effectiveness of Push and Pull Learning Strategies in Construction Management.

    Science.gov (United States)

    Santos, Aguinaldo; Powell, James Alfred

    2001-01-01

    Study of a construction contractor modernizing production showed that creation of an effective learning mood was more likely in a supportive environment in which people explore their actions as they work ("pull learning"). However, an external change agent ("push learning") was useful in provoking the reflection that triggered workplace learning.…

  16. Effectiveness of Push and Pull Learning Strategies in Construction Management.

    Science.gov (United States)

    Santos, Aguinaldo; Powell, James Alfred

    2001-01-01

    Study of a construction contractor modernizing production showed that creation of an effective learning mood was more likely in a supportive environment in which people explore their actions as they work ("pull learning"). However, an external change agent ("push learning") was useful in provoking the reflection that triggered workplace learning.…

  17. Push-pull membrane mirrors for adaptive optics.

    Science.gov (United States)

    Bonora, Stefano; Poletto, Luca

    2006-12-11

    We propose an improvement to the electrostatic membrane deformable mirror technique introducing push-pull capability that increases the performance in the correction of optical aberrations. The push-pull effect is achieved by the addition of some transparent electrodes on the top of the device. The transparent electrode is an indium-tin-oxide coated glass. The improvement of the mirror in generating surfaces is demonstrated by the comparison with a pull membrane mirror. The control is carried out in open loop by the knowledge of the response of each single electrode. An effective iterative strategy for the clipping management is presented. The performances are evaluated both in terms of Zernike polynomials generation and in terms of aberrations compensation based on the statistics of human eyes.

  18. Push-pull membrane mirrors for adaptive optics

    Science.gov (United States)

    Bonora, Stefano; Poletto, Luca

    2006-12-01

    We propose an improvement to the electrostatic membrane deformable mirror technique introducing push-pull capability that increases the performance in the correction of optical aberrations. The push-pull effect is achieved by the addition of some transparent electrodes on the top of the device. The transparent electrode is an indium-tin-oxide coated glass. The improvement of the mirror in generating surfaces is demonstrated by the comparison with a pull membrane mirror. The control is carried out in open loop by the knowledge of the response of each single electrode. An effective iterative strategy for the clipping management is presented. The performances are evaluated both in terms of Zernike polynomials generation and in terms of aberrations compensation based on the statistics of human eyes.

  19. Pull or Push? Octopuses Solve a Puzzle Problem

    Science.gov (United States)

    Richter, Jonas N.; Hochner, Binyamin; Kuba, Michael J.

    2016-01-01

    Octopuses have large brains and exhibit complex behaviors, but relatively little is known about their cognitive abilities. Here we present data from a five-level learning and problem-solving experiment. Seven octopuses (Octopus vulgaris) were first trained to open an L shaped container to retrieve food (level 0). After learning the initial task all animals followed the same experimental protocol, first they had to retrieve this L shaped container, presented at the same orientation, through a tight fitting hole in a clear Perspex partition (level 1). This required the octopuses to perform both pull and release or push actions. After reaching criterion the animals advanced to the next stage of the test, which would be a different consistent orientation of the object (level 2) at the start of the trial, an opaque barrier (level 3) or a random orientation of the object (level 4). All octopuses were successful in reaching criterion in all levels of the task. At the onset of each new level the performance of the animals dropped, shown as an increase in working times. However, they adapted quickly so that overall working times were not significantly different between levels. Our findings indicate that octopuses show behavioral flexibility by quickly adapting to a change in a task. This can be compared to tests in other species where subjects had to conduct actions comprised of a set of motor actions that cannot be understood by a simple learning rule alone. PMID:27003439

  20. Pull or Push? Octopuses Solve a Puzzle Problem.

    Directory of Open Access Journals (Sweden)

    Jonas N Richter

    Full Text Available Octopuses have large brains and exhibit complex behaviors, but relatively little is known about their cognitive abilities. Here we present data from a five-level learning and problem-solving experiment. Seven octopuses (Octopus vulgaris were first trained to open an L shaped container to retrieve food (level 0. After learning the initial task all animals followed the same experimental protocol, first they had to retrieve this L shaped container, presented at the same orientation, through a tight fitting hole in a clear Perspex partition (level 1. This required the octopuses to perform both pull and release or push actions. After reaching criterion the animals advanced to the next stage of the test, which would be a different consistent orientation of the object (level 2 at the start of the trial, an opaque barrier (level 3 or a random orientation of the object (level 4. All octopuses were successful in reaching criterion in all levels of the task. At the onset of each new level the performance of the animals dropped, shown as an increase in working times. However, they adapted quickly so that overall working times were not significantly different between levels. Our findings indicate that octopuses show behavioral flexibility by quickly adapting to a change in a task. This can be compared to tests in other species where subjects had to conduct actions comprised of a set of motor actions that cannot be understood by a simple learning rule alone.

  1. Using metaheuristic and fuzzy system for the optimization of material pull in a push-pull flow logistics network

    OpenAIRE

    Afshin Mehrsai; Hamid-Reza Karimi; Klaus-Dieter Thoben; Bernd Scholz-Reiter

    2013-01-01

    Alternative material flow strategies in logistics networks have crucial influences on the overall performance of the networks. Material flows can follow push, pull, or hybrid systems. To get the advantages of both push and pull flows in networks, the decoupling-point strategy is used as coordination mean. At this point, material pull has to get optimized concerning customer orders against pushed replenishment-rates. To compensate the ambiguity and uncertainty of both dynamic flows, fuzzy set ...

  2. Using Metaheuristic and Fuzzy System for the Optimization of Material Pull in a Push-Pull Flow Logistics Network

    OpenAIRE

    Afshin Mehrsai; Hamid-Reza Karimi; Klaus-Dieter Thoben; Bernd Scholz-Reiter

    2013-01-01

    Alternative material flow strategies in logistics networks have crucial influences on the overall performance of the networks. Material flows can follow push, pull, or hybrid systems. To get the advantages of both push and pull flows in networks, the decoupling-point strategy is used as coordination mean. At this point, material pull has to get optimized concerning customer orders against pushed replenishment-rates. To compensate the ambiguity and uncertainty of both dynamic flows, fuzzy set ...

  3. Push and pull factors of national parks in South Africa

    OpenAIRE

    Slabbert, E.; Viviers, P.

    2012-01-01

    South Africa's national parks are one of South Africa's major attractions. Since visitors are among the most important role players in the sustainability of these parks, and in-depth research is needed to understand them, this article analyses the push and pull factors that bring them to the parks. The study used a structured questionnaire to collect data on these factors and the socio-demographic profile of the visitors. Surveys conducted at nine National Parks produced 1300 questionnaires. ...

  4. β-Functionalized Push-Pull opp-Dibenzoporphyrins.

    Science.gov (United States)

    Jinadasa, R G Waruna; Fang, Yuanyuan; Kumar, Siddhartha; Osinski, Allen J; Jiang, Xiaoqin; Ziegler, Christopher J; Kadish, Karl M; Wang, Hong

    2015-12-18

    The synthesis of a series of β-functionalized push-pull dibenzoporphyrins was realized. These porphyrins display subtle push-pull effects, demonstrating the exceptional tunability of their electronic and electrochemical properties. The UV-vis spectra of these porphyrins show unique absorption patterns with shouldered Soret bands and extra absorptions in the Q-band region. Stronger electron-withdrawing groups display more significant bathochromic shifts of the Soret bands. The fluorescence spectra of these porphyrins show strong near-IR emission bands (600-850 nm). In particular, fluorescence quenching effect was observed for pyridyl carrying push-pull porphyrin 4c in the presence of an acid. TFA titration study of 4c using UV-vis and fluorescence spectroscopy reveals that the fluorescence quenching can be mainly attributed to the protonation of the pyridyl groups of 4c. The versatile synthetic methods developed in this work may open a door to access a large number of functionalized organic materials that are currently unavailable. The structure-property studies provided in this work may provide useful guidelines for the design of new generations of materials in dye-sensitized solar cells, in nonlinear optical applications, as fluorescence probes, as well as sensitizers for photodynamic therapy.

  5. Psychophysical basis for maximum pushing and pulling forces: A review and recommendations.

    Science.gov (United States)

    Garg, Arun; Waters, Thomas; Kapellusch, Jay; Karwowski, Waldemar

    2014-03-01

    The objective of this paper was to perform a comprehensive review of psychophysically determined maximum acceptable pushing and pulling forces. Factors affecting pushing and pulling forces are identified and discussed. Recent studies show a significant decrease (compared to previous studies) in maximum acceptable forces for males but not for females when pushing and pulling on a treadmill. A comparison of pushing and pulling forces measured using a high inertia cart with those measured on a treadmill shows that the pushing and pulling forces using high inertia cart are higher for males but are about the same for females. It is concluded that the recommendations of Snook and Ciriello (1991) for pushing and pulling forces are still valid and provide reasonable recommendations for ergonomics practitioners. Regression equations as a function of handle height, frequency of exertion and pushing/pulling distance are provided to estimate maximum initial and sustained forces for pushing and pulling acceptable to 75% male and female workers. At present it is not clear whether pushing or pulling should be favored. Similarly, it is not clear what handle heights would be optimal for pushing and pulling. Epidemiological studies are needed to determine relationships between psychophysically determined maximum acceptable pushing and pulling forces and risk of musculoskeletal injuries, in particular to low back and shoulders.

  6. A high-sensitivity push-pull magnetometer

    Science.gov (United States)

    Breschi, E.; Grujić, Z. D.; Knowles, P.; Weis, A.

    2014-01-01

    We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/√Hz , using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/√Hz .

  7. A high-sensitivity push-pull magnetometer

    CERN Document Server

    Breschi, E; Knowles, P; Weis, A

    2013-01-01

    We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/\\sqrt(Hz) using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/\\sqrt(Hz).

  8. N -annulated perylene-based push-pull-type sensitizers

    KAUST Repository

    Qi, Qingbiao

    2015-02-06

    Alkoxy-wrapped N-annulated perylene (NP) was synthesized and used as a rigid and coplanar π-linker for three push-pull type metal-free sensitizers QB1-QB3. Their optical and electrochemical properties were tuned by varying the structure of acceptor. These new dyes were applied in Co(II)/(III) based dye-sensitized solar cells, and power conversion efficiency up to 6.95% was achieved, indicating that NP could be used as a new building block for the design of high-performance sensitizers in the future.

  9. Design of push-pull system to control diesel particular matter inside a dead-end entry.

    Science.gov (United States)

    Zheng, Yi; Thiruvengadam, Magesh; Lan, Hai; Tien, Jerry C

    Diesel particulate matter (DPM) is considered to be carcinogenic after prolonged exposure. With more diesel-powered equipment used in underground mines, miners' exposure to DPM has become an increasing concern. This paper used computational fluid dynamics method to study the DPM dispersion in a dead-end entry with loading operation. The effects of different push-pull ventilation systems on DPM distribution were evaluated to improve the working conditions for underground miners. The four push-pull systems considered include: long push and short pull tubing; short push and long pull tubing, long push and curved pull tubing, and short push and curved pull tubing. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup local ventilation, select DPM control strategies and for DPM annual training for underground miners.

  10. The push-pull theory of migration and its application.

    Science.gov (United States)

    Zhang, Z; Zhang, T; Zhang, Q

    1997-01-01

    Since the start of the 1980s, a migration project involving 550,000 people in Gansu and Ningxia provinces has been underway as part of a program to explore the natural resources, eliminate poverty, and improve the environment. A similar project has been carried out in Xinjiang, involving hundreds of thousands of people, and 400,000 people in the karst areas of Guangxi have moved to open up and cultivate barren hills. Millions of people will eventually be moved out of the impoverished areas of western China. The success of these migration projects over the past decade, however, has also brought some social and ecological problems. In order for the projects to have scientific footing and to follow a standard procedure, a theoretical model must be established which fits the conditions in China concerning the mechanism, magnitude, settlement planning, impact evaluation, and management system of migration. To that end, the authors conducted this study based upon empirical research. Sections cover a review of the push-pull mechanism theory in western demographics and the push-pull mechanism theory in China as part of the Help-the-Poor program and its application.

  11. Towards electrochromic devices having visible color switching using electronic push-push and push-pull cinnamaldehyde derivatives.

    Science.gov (United States)

    Navarathne, Daminda; Skene, W G

    2013-12-11

    A series of symmetric and unsymmetric conjugated azomethines derived from cinnamaldehyde and 2,5-diaminothiophene-3,4-dicarboxylic acid diethyl ester were prepared. The optical, electrochemical, and spectroelectrochemical properties of the electronic push-pull and push-push triads were investigated. Their properties could be tuned contingent on the cinnamaldehyde's electron withdrawing and donating substituents. The push-push symmetric derivative exhibited positive solvatochromism with the absorbance spanning some 31 nm, depending on the solvent polarity. Solvent dependent spectroelectrochemistry was also found for the symmetric push-push azomethine. The color of the neutral state and radical cation spanned 215 nm. The most pronounced color transition of the purple colored material was found in dimethyl sulfoxide (DMSO), where the color bleached with electrochemical oxidation. This was a result of the absorbance shifting into the near infrared (NIR) and not from decomposition of the azomethine. Electrochromic devices with the azomethines possessing desired reversible oxidation and color changes in the visible were fabricated and tested to demonstrate the applicability of these azomethine triads in devices.

  12. Push-Pull Tests for Evaluating the Aerobic Cometabolism of Chlorinated Aliphatic Hydrocarbons

    Science.gov (United States)

    2006-09-01

    RESULTS FROM FIELD PUSH-PULL TESTS CONDUCTED AT McCLELLAN AFB , CALIFORNIA .........................17 4.2 EXAMPLE RESULTS FROM FIELD PUSH-PULL TESTS...Logistics Center, Washington. 3.2.2 McClellan Site Description Field tests were performed at the site of the former McAFB near Sacramento , California...at full scale Conducted at full scale 17 4.1 EXAMPLE RESULTS FROM FIELD PUSH-PULL TESTS CONDUCTED AT McCLELLAN AFB , CALIFORNIA Transport

  13. Push-Pull Tests for Evaluating the Aerobic Cometabolism of Chlorinated Aliphatic Hydrocarbons: Cost & Performance Report

    Science.gov (United States)

    2006-09-01

    EXAMPLE RESULTS FROM FIELD PUSH-PULL TESTS CONDUCTED AT McCLELLAN AFB , CALIFORNIA .........................17 4.2 EXAMPLE RESULTS FROM FIELD PUSH-PULL...Logistics Center, Washington. 3.2.2 McClellan Site Description Field tests were performed at the site of the former McAFB near Sacramento , California...Conducted at full scale Conducted at full scale 17 4.1 EXAMPLE RESULTS FROM FIELD PUSH-PULL TESTS CONDUCTED AT McCLELLAN AFB , CALIFORNIA Transport

  14. Technology and trend management at the interface of technology push and market pull

    DEFF Research Database (Denmark)

    Maier, Maximilian; Hofmann, Maximilian; Brem, Alexander

    2016-01-01

    Technology push and market pull innovation strategies are playing an important role for the effective management of ideas, technologies, and trends. The coexistence of these two approaches led to many debates and the focus switched several times from putting more effort into technology push aspects...... to fostering market pull approaches in the last decades. Still, there is no in-depth exploration of the interface of technology push and market pull and only few conceptual models are dealing with the connection between technology push and market pull in particular. Therefore, this study puts an exploratory...... focus on the innovation management processes of a global outdoor manufacturer with a special emphasis on the interface between technology push and market pull. From the case findings and our literature we conceptualise a non-linear innovation model that systematically integrates market pull...

  15. Adult Literacy in Africa: The Push and Pull Factors

    Science.gov (United States)

    Omolewa, Michael

    2008-11-01

    This paper examines the question of why Africa has made such slow progress towards the goal of eradicating illiteracy, and why it remains an exceptionally disadvantaged region in this respect. The article surveys the history of the development of literacy in Africa from colonial times to the present day, focusing on the role of adult education in pursuing the goal of universal literacy. The author seeks to identify both the "push" factors (those favouring the pursuit of this goal) and the "pull" factors (the obstacles and hindrances), examining these factors at the local, national and international levels. The author concludes that, while the literacy challenge in Africa remains a formidable one, there are examples of successful initiatives that give hope for the future.

  16. Prostitution push and pull: male and female perspectives.

    Science.gov (United States)

    Vanwesenbeeck, Ine

    2013-01-01

    Smith, Grov, Seal, and McCall's (2012) analysis, focusing on how young men become, and stay, involved in male escorting, is a welcome contribution to the still relatively thin male sex worker literature. For this study group, notably supportive working surroundings, effective coping strategies, and a growing sense of "self-efficacy" eventually turn sex work into an increasingly comfortable experience and viable moneymaking option. In this commentary, I add some reflections from a broader perspective to these insights. I also consider some evidence on the numbers of men and women in sex work and make some observations on male versus female positions related to push and pull factors, stigma, and the experience of sex work.

  17. Technology push, market pull, and the Valley of Death

    Science.gov (United States)

    Swift, Gregory W.

    2005-09-01

    The Valley of Death is the gap between fundamental research and product development, where apparently promising technologies can stall or disappear. Fundamental researchers may hope for potential applications of their work, and they try to push technology based on their research. Businesses may hope that new technology might serve their market needs, and they try to find promising new technologies that can be pulled toward practical use. The valley between the researchers and the businesses can be surprisingly twisted and thorny, despite government attempts to build roads across it. The histories of cryogenic engineering in the late 20th century and of thermoacoustics work at Los Alamos offer examples of both useful and misguided strategies in this valley. Although global thermoacoustics R&D has not (yet?) been as successful as cryogenic engineering, thermoacoustics has thus far avoided some of the worst pitfalls in the valley.

  18. Enhanced Basicity of Push-Pull Nitrogen Bases in the Gas Phase.

    Science.gov (United States)

    Raczyńska, Ewa D; Gal, Jean-François; Maria, Pierre-Charles

    2016-11-23

    Nitrogen bases containing one or more pushing amino-group(s) directly linked to a pulling cyano, imino, or phosphoimino group, as well as those in which the pushing and pulling moieties are separated by a conjugated spacer (C═X)n, where X is CH or N, display an exceptionally strong basicity. The n-π conjugation between the pushing and pulling groups in such systems lowers the basicity of the pushing amino-group(s) and increases the basicity of the pulling cyano, imino, or phosphoimino group. In the gas phase, most of the so-called push-pull nitrogen bases exhibit a very high basicity. This paper presents an analysis of the exceptional gas-phase basicity, mostly in terms of experimental data, in relation with structure and conjugation of various subfamilies of push-pull nitrogen bases: nitriles, azoles, azines, amidines, guanidines, vinamidines, biguanides, and phosphazenes. The strong basicity of biomolecules containing a push-pull nitrogen substructure, such as bioamines, amino acids, and peptides containing push-pull side chains, nucleobases, and their nucleosides and nucleotides, is also analyzed. Progress and perspectives of experimental determinations of GBs and PAs of highly basic compounds, termed as "superbases", are presented and benchmarked on the basis of theoretical calculations on existing or hypothetical molecules.

  19. Force direction in pushing and pulling and Musculo-Skeletal load

    NARCIS (Netherlands)

    Looze, M.P. de; Kuijer, P.P.F.M.

    1999-01-01

    In pushing and pulling wheeled objects, the effect of the exerted force on local musculo-skeletal loads depends on the direction of force exertion. Several questions about the direction of force exertion in pushing and pulling, the effects of handle height and force level on force direction, and the

  20. Force direction in pushing and pulling and Musculo-Skeletal load

    NARCIS (Netherlands)

    Looze, M.P. de; Kuijer, P.P.F.M.

    1999-01-01

    In pushing and pulling wheeled objects, the effect of the exerted force on local musculo-skeletal loads depends on the direction of force exertion. Several questions about the direction of force exertion in pushing and pulling, the effects of handle height and force level on force direction, and the

  1. Push-Pull Ventilation in a Painting Shop for Large Steel Constructions

    DEFF Research Database (Denmark)

    Svidt, Kjeld; Heiselberg, Per

    This paper describes the analysis of a push-pull ventilation system for a painting shop that is used for painting steel chimneys and windmill towers.......This paper describes the analysis of a push-pull ventilation system for a painting shop that is used for painting steel chimneys and windmill towers....

  2. Design of push-pull system to control diesel particular matter inside a dead-end entry

    Institute of Scientific and Technical Information of China (English)

    Yi Zheng; Magesh Thiruvengadam; Hai Lan; Jerry C Tien

    2015-01-01

    Diesel particulate matter (DPM) is considered to be carcinogenic after prolonged exposure. With more diesel-powered equipment used in underground mines, miners’ exposure to DPM has become an increasing concern. This paper used computational fluid dynamics method to study the DPM dispersion in a dead-end entry with loading operation. The effects of different push–pull ventilation systems on DPM distribution were evaluated to improve the working conditions for underground miners. The four push–pull systems considered include:long push and short pull tubing;short push and long pull tubing, long push and curved pull tubing, and short push and curved pull tubing. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup local ventilation, select DPM control strategies and for DPM annual training for underground miners.

  3. Push and pull forces in lipid raft formation: the push can be as important as the pull.

    Science.gov (United States)

    Wang, Chang; Krause, Martin R; Regen, Steven L

    2015-01-21

    Nearest-neighbor recognition measurements have been made using exchangeable mimics of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine in the liquid-ordered (lo) and liquid-disordered (ld) states. In the ld phase, the net interaction between these two lipids is repulsive. In the lo phase, their interactions are neither attractive nor repulsive. These results, together with previous nearest-neighbor measurements, imply that the overall driving force for lipid domain formation in bilayers composed of high-melting lipids, low-melting lipids, and cholesterol, corresponds to a strong pull (attraction) between the high-melting lipids and cholesterol, a significant push (repulsion) between the low-melting and high-melting lipids, and a significant push between the low-melting lipids and cholesterol. In a broader context, these results provide strong support for the notion that repulsive forces play a major role in the formation of lipid rafts.

  4. The use of push-pull strategies in integrated pest management.

    Science.gov (United States)

    Cook, Samantha M; Khan, Zeyaur R; Pickett, John A

    2007-01-01

    Push-pull strategies involve the behavioral manipulation of insect pests and their natural enemies via the integration of stimuli that act to make the protected resource unattractive or unsuitable to the pests (push) while luring them toward an attractive source (pull) from where the pests are subsequently removed. The push and pull components are generally nontoxic. Therefore, the strategies are usually integrated with methods for population reduction, preferably biological control. Push-pull strategies maximize efficacy of behavior-manipulating stimuli through the additive and synergistic effects of integrating their use. By orchestrating a predictable distribution of pests, efficiency of population-reducing components can also be increased. The strategy is a useful tool for integrated pest management programs reducing pesticide input. We describe the principles of the strategy, list the potential components, and present case studies reviewing work on the development and use of push-pull strategies in each of the major areas of pest control.

  5. Using Metaheuristic and Fuzzy System for the Optimization of Material Pull in a Push-Pull Flow Logistics Network

    Directory of Open Access Journals (Sweden)

    Afshin Mehrsai

    2013-01-01

    Full Text Available Alternative material flow strategies in logistics networks have crucial influences on the overall performance of the networks. Material flows can follow push, pull, or hybrid systems. To get the advantages of both push and pull flows in networks, the decoupling-point strategy is used as coordination mean. At this point, material pull has to get optimized concerning customer orders against pushed replenishment-rates. To compensate the ambiguity and uncertainty of both dynamic flows, fuzzy set theory can practically be applied. This paper has conceptual and mathematical parts to explain the performance of the push-pull flow strategy in a supply network and to give a novel solution for optimizing the pull side employing Conwip system. Alternative numbers of pallets and their lot-sizes circulating in the assembly system are getting optimized in accordance with a multi-objective problem; employing a hybrid approach out of meta-heuristics (genetic algorithm and simulated annealing and fuzzy system. Two main fuzzy sets as triangular and trapezoidal are applied in this technique for estimating ill-defined waiting times. The configured technique leads to smoother flows between push and pull sides in complex networks. A discrete-event simulation model is developed to analyze this thesis in an exemplary logistics network with dynamics.

  6. Investigating groundwater arsenic contamination using aquifer push-pull test

    Science.gov (United States)

    Daigle, A. R.; Jin, Q.

    2009-12-01

    The groundwater of the Southern Willamette Basin, OR is contaminated with arsenic at concentrations as high as several ppm. A single-well push-pull test was conducted to investigate how microbial metabolisms control arsenic occurrence and levels in the bedrock aquifer of the area. During the experiments, a test solution containing ethanol was first injected into the aquifer. As the experiment progressed, dissolved gasses, groundwater, and sediment were sampled to monitor the variations in the chemical parameters, including the speciation of iron, sulfur, and arsenic, in the aquifer. Ethanol amendment stimulated a series of microbial metabolisms, including arsenate reduction, iron reduction, and sulfate reduction. Iron reduction released arsenic sorbed onto the aquifer sediments, increasing groundwater arsenic levels. Arsenate reduction converted arsenate to arsenite and, as a result, most arsenic occurred as arsenite in the groundwater. Results of the experiments demonstrate how different microbial functional groups influenced arsenic contamination in the area. These results also shed new light on potential bioremediation strategies in the area.

  7. Push-Pull Air Curtain Performances for VOCs Containment in an Industrial Process

    National Research Council Canada - National Science Library

    A. Aubert; C. Solliec

    2011-01-01

    ...) containment system using an air curtain (push-pull type) on a manual workstation. This work combines CFD numerical simulations of the air curtain system and experimental studies on a real scale test bench...

  8. Antecedents of retailer loyalty: Simultaneously investigating channel push and consumer pull effects

    National Research Council Canada - National Science Library

    Chiou, Jyh-Shen; Wu, Lei-Yu; Chuang, Min-Chieh

    2010-01-01

    This study includes information technology (IT) related industries as the focus and aims to examine the antecedents of retailer loyalty toward brand owners by simultaneously investigating push and pull effects in the channel system...

  9. "PUSH" AND "PULL" SYSTEMS IN SUPPLY CHAIN MANAGEMENT. CORRELATIVE APPROACHES IN THE MILITARY FIELD

    National Research Council Canada - National Science Library

    Gheorghe Minculete; Polixenia Olar

    2016-01-01

    .... In these circumstances, the complexity of the economic and military environments determines company managers and military leaders to act by way of "push" and "pull" systems in order to make their own...

  10. Push and pull factors of three Afrikaans Arts Festivals in South Africa ...

    African Journals Online (AJOL)

    South African Journal for Research in Sport, Physical Education and Recreation ... across the three events, followed by factor analyses regarding the push and pull ... not only focus their marketing campaigns on the identified travel motives, but ...

  11. Hyperpolarizabilities of Push-Pull Polyenes: Experimental Results and a New Two-State Model

    Science.gov (United States)

    Perry, J.; Bourhill, G.; Marder, S.; Lu, D.; Chen, G.; Goddard, W.

    1994-01-01

    Recent work has demonstrated a correlation between the geometry (i.e., the bond length alteration, BLA) and the first and second hyperpolarizabilities (betta and gamma) of donor-acceptor substituted (push-pull)polyenes.

  12. Should arts festivals focus on push or pull factors in marketing efforts?

    OpenAIRE

    Viviers, Pierre-Andre; Slabbert, Elmarie

    2014-01-01

    The rapid growth of arts festivals has led to increased competition resulting in festivals competing for visitors‟ money and leisure time. The aim of this article is to determine the importance of motivational push and/or pull factors of festival goers with regard to two national arts festivals in South Africa. Not only were the relevance and importance of push and pull factors identified, their differences for various socio-demographic subgroups were also discussed. A questionnaire was used ...

  13. Evaluating a push-pull strategy for management of Drosophila suzukii Matsumura in red raspberry.

    Science.gov (United States)

    Wallingford, Anna K; Cha, Dong H; Loeb, Gregory M

    2017-07-17

    Drosophila suzukii Matsumura is a serious pest of small fruits that lays its eggs in growing fruit. Current management strategies rely on an unsustainable schedule of foliar applications of chemical insecticides. Alternative approaches to suppressing oviposition are under investigation, such as attract-and-kill and the use of oviposition deterrents. Here, we evaluated two behavioral control approaches in combination as a push-pull strategy using laboratory and field assays. In laboratory caged assays, both an attractive mass trapping device (pull) and an oviposition deterrent (push: 1-octen-3-ol) reduced oviposition by D. suzukii, and the combination of the two (push-pull) resulted in significantly greater reduction than either treatment alone. In field experiments, oviposition reduction was observed in fruit from plots treated with oviposition deterrent (push) or a combination of mass trapping devices and deterrent (push-pull) compared with fruit from control plots. However, oviposition in plots with mass trapping devices (pull) was higher than observed in all other treatments. Additionally, the protection provided by the deterrent in push plots extended to the entire plot rather than just in fruit closest to deterrent dispensers. Push-pull treatments negatively affected D. suzukii infestation in both laboratory and field experiments. The reduction in oviposition observed in laboratory experiments was based on the additive effect of push and pull components acting on a finite population, while the reduction observed in field experiments appeared to be mainly based on the effect of pull components. We discuss potential underlying reasons for the discrepancy results and suggest potential improvements. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  14. Modeling and control of a push-pull converter for photovoltaic microinverters operating in island mode

    OpenAIRE

    Trujillo Rodríguez, César Leonardo; VELASCO DE LA FUENTE, DAVID; Figueres Amorós, Emilio; Garcerá Sanfeliú, Gabriel; Ortega, Rubén

    2011-01-01

    This paper presents the modeling and control of a push-pull converter integrated into a two-stage photovoltaic microinverter operating in island mode without backup energy storage components (batteries). A push-pull small signal model is presented, from which they are derived all transfer functions needed to implement the controllers that regulate the output current, input voltage and output voltage interacting with the MPPT algorithm. A significant contribution of the paper is the proposal o...

  15. Study on pollution control in residential kitchen based on the push-pull ventilation system

    DEFF Research Database (Denmark)

    Zhou, Bin; Chen, Feng; Dong, Zhibo

    2016-01-01

    Highlights •The push-pull ventilation system is proposed to improve IAQ inside kitchen, where air is supplied through slot air curtain and then exhausted through range hood. •CO2 reduction efficiency with application of air curtain in experiment and simulation in breathing zone was 23.7% and 23.1.......1%, respectively. •By orthogonal method, the influence of factors on pollution control of the push-pull ventilation system was presented....

  16. Numerical investigation of turbulent diffusion in push-pull and exhaust fume cupboards.

    Science.gov (United States)

    Chern, Ming-Jyh; Cheng, Wei-Ying

    2007-08-01

    The aim of this study is to investigate airflow motions and associated pollutant distributions in fume hoods. Currently, most exhaust fume hoods are designed to use an airflow induced by a fan at the top to remove pollutants. Ambient fluids are drawn, flowing toward the opening and subsequently turning to the outlet at the roof. Pollutants are supposedly captured by the airflow and brought out from the cupboard. The present numerical study based on the finite-volume method and the standard k-epsilon turbulence model simulates flow patterns and pollutant distributions in an exhaust fume hood with and without a manikin present. Subsequently, a push-pull air curtain technique is applied to a fume cupboard. To investigate the capturing performance of a push-pull fume cupboard, numerical approaches are used to simulate flow and concentration variations. Numerical results reveal that four characteristic flow modes exist for a variety of speed ratios of push-pull flows and openings. A concave curtain mode which has a fast pull flow and a weak push flow is suggested for the operation of a push-pull fume cupboard. According to ANSI-ASHRAE Standard 110-1995, the local concentration at the specified point is fume cupboard are not affected by a manikin. In terms of those predicted results, it turns out that a push-pull fume cupboard successfully captures pollutants and prevents an operator from breathing pollutants.

  17. Influence of molecular designs on polaronic and vibrational transitions in a conjugated push-pull copolymer

    Science.gov (United States)

    Cobet, Christoph; Gasiorowski, Jacek; Menon, Reghu; Hingerl, Kurt; Schlager, Stefanie; White, Matthew S.; Neugebauer, Helmut; Sariciftci, N. Serdar; Stadler, Philipp

    2016-01-01

    Electron-phonon interactions of free charge-carriers in doped pi-conjugated polymers are conceptually described by 1-dimensional (1D) delocalization. Thereby, polaronic transitions fit the 1D-Froehlich model in quasi-confined chains. However, recent developments in conjugated polymers have diversified the backbones to become elaborate heterocylcic macromolecules. Their complexity makes it difficult to investigate the electron-phonon coupling. In this work we resolve the electron-phonon interactions in the ground and doped state in a complex push-pull polymer. We focus on the polaronic transitions using in-situ spectroscopy to work out the differences between single-unit and push-pull systems to obtain the desired structural- electronic correlations in the doped state. We apply the classic 1D-Froehlich model to generate optical model fits. Interestingly, we find the 1D-approach in push-pull polarons in agreement to the model, pointing at the strong 1D-character and plain electronic structure of the push-pull structure. In contrast, polarons in the single-unit polymer emerge to a multi- dimensional problem difficult to resolve due to their anisotropy. Thus, we report an enhancement of the 1D-character by the push-pull concept in the doped state - an important view in light of the main purpose of push-pull polymers for photovoltaic devices. PMID:27731421

  18. Research on Flow Field Characteristics Affected by Obstacles of Pull-Push Ventilation System of Plating Tanks through Numerical Simulation

    OpenAIRE

    Hu Hong; Yi Can-nan

    2016-01-01

    Pull-push ventilation system, with high capture efficiency, is universally used to capture contaminants from containment generation where can’t be enclosed and where the working area is large. When there are obstacles between the pull hood and the push hood, the air jet will disperse, leaving contaminants out of control, causing atmosphere polluted. This paper aims to discuss flow filed of pull-push ventilation system, located in some tank of some plating workshop, with obstacles between pull...

  19. Research on Flow Field Characteristics Affected by Obstacles of Pull-Push Ventilation System of Plating Tanks through Numerical Simulation

    OpenAIRE

    Hu Hong; Yi Can-nan

    2016-01-01

    Pull-push ventilation system, with high capture efficiency, is universally used to capture contaminants from containment generation where can’t be enclosed and where the working area is large. When there are obstacles between the pull hood and the push hood, the air jet will disperse, leaving contaminants out of control, causing atmosphere polluted. This paper aims to discuss flow filed of pull-push ventilation system, located in some tank of some plating workshop, with obstacles between pull...

  20. Positioning of microtubule organizing centers by cortical pushing and pulling forces

    Science.gov (United States)

    Pavin, Nenad; Laan, Liedewij; Ma, Rui; Dogterom, Marileen; Jülicher, Frank

    2012-10-01

    Positioning of microtubule (MT) organizing centers with respect to the confining geometry of cells depends on pushing and/or pulling forces generated by MTs that interact with the cell cortex (Dogterom et al 2005 Curr. Opin. Cell Biol. 17 67-74). How, in living cells, these forces lead to proper positioning is still largely an open question. Recently, it was shown by in vitro experiments using artificial microchambers that in a square geometry, MT asters center more reliably by a combination of pulling and pushing forces than by pushing forces alone (Laan et al 2012a Cell 148 502-14). These findings were explained by a physical description of aster mechanics that includes slipping of pushing MT ends along chamber boundaries. In this paper, we extend that theoretical work by studying the influence of the shape of the confining geometry on the positioning process. We find that pushing and pulling forces can have centering or off-centering behavior in different geometries. Pushing forces center in a one-dimensional and a square geometry, but lead to off-centering in a circle if slipping is sufficiently pronounced. Pulling forces, however, do not center in a one-dimensional geometry, but improve centering in a circle and a square. In an elongated stadium geometry, positioning along the short axis depends mainly on pulling forces, while positioning along the long axis depends mainly on pushing forces. Our theoretical results suggest that different positioning strategies could be used by different cell types.

  1. Micro/nano-mechanical test system employing tensile test holder with push-to-pull transformer

    Science.gov (United States)

    Oh, Yunje; Cyrankowski, Edward; Shan, Zhiwei; Asif, Syed Amanula Syed

    2013-05-07

    A micromachined or microelectromechanical system (MEMS) based push-to-pull mechanical transformer for tensile testing of micro-to-nanometer scale material samples including a first structure and a second structure. The second structure is coupled to the first structure by at least one flexible element that enables the second structure to be moveable relative to the first structure, wherein the second structure is disposed relative to the first structure so as to form a pulling gap between the first and second structures such that when an external pushing force is applied to and pushes the second structure in a tensile extension direction a width of the pulling gap increases so as to apply a tensile force to a test sample mounted across the pulling gap between a first sample mounting area on the first structure and a second sample mounting area on the second structure.

  2. Micro/nano-mechanical test system employing tensile test holder with push-to-pull transformer

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Yunje; Cyrankowski, Edward; Shan, Zhiwei; Syed Asif, Syed Amanula

    2014-07-29

    A micromachined or microelectromechanical system (MEMS) based push-to-pull mechanical transformer for tensile testing of micro-to-nanometer scale material samples including a first structure and a second structure. The second structure is coupled to the first structure by at least one flexible element that enables the second structure to be moveable relative to the first structure, wherein the second structure is disposed relative to the first structure so as to form a pulling gap between the first and second structures such that when an external pushing force is applied to and pushes the second structure in a tensile extension direction a width of the pulling gap increases so as to apply a tensile force to a test sample mounted across the pulling gap between a first sample mounting area on the first structure and a second sample mounting area on the second structure.

  3. Technology and trend management at the interface of technology push and market pull

    DEFF Research Database (Denmark)

    Maier, Maximilian; Hofmann, Maximilian; Brem, Alexander

    2016-01-01

    Technology push and market pull innovation strategies are playing an important role for the effective management of ideas, technologies, and trends. The coexistence of these two approaches led to many debates and the focus switched several times from putting more effort into technology push aspects...... focus on the innovation management processes of a global outdoor manufacturer with a special emphasis on the interface between technology push and market pull. From the case findings and our literature we conceptualise a non-linear innovation model that systematically integrates market pull...... and technology push activities. The model was tested for its practical applicability by reflecting it against the case company's organisational capabilities. Further research implications are discussed as well as implications for the management of the innovation process in practice, which highlights especially...

  4. Push-me-pull-you: how microtubules organize the cell interior.

    Science.gov (United States)

    Tolić-Nørrelykke, Iva M

    2008-09-01

    Dynamic organization of the cell interior, which is crucial for cell function, largely depends on the microtubule cytoskeleton. Microtubules move and position organelles by pushing, pulling, or sliding. Pushing forces can be generated by microtubule polymerization, whereas pulling typically involves microtubule depolymerization or molecular motors, or both. Sliding between a microtubule and another microtubule, an organelle, or the cell cortex is also powered by molecular motors. Although numerous examples of microtubule-based pushing and pulling in living cells have been observed, it is not clear why different cell types and processes employ different mechanisms. This review introduces a classification of microtubule-based positioning strategies and discusses the efficacy of pushing and pulling. The positioning mechanisms based on microtubule pushing are efficient for movements over small distances, and for centering of organelles in symmetric geometries. Mechanisms based on pulling, on the other hand, are typically more elaborate, but are necessary when the distances to be covered by the organelles are large, and when the geometry is asymmetric and complex. Thus, taking into account cell geometry and the length scale of the movements helps to identify general principles of the intracellular layout based on microtubule forces.

  5. Push-me-pull-you: how microtubules organize the cell interior

    Science.gov (United States)

    2008-01-01

    Dynamic organization of the cell interior, which is crucial for cell function, largely depends on the microtubule cytoskeleton. Microtubules move and position organelles by pushing, pulling, or sliding. Pushing forces can be generated by microtubule polymerization, whereas pulling typically involves microtubule depolymerization or molecular motors, or both. Sliding between a microtubule and another microtubule, an organelle, or the cell cortex is also powered by molecular motors. Although numerous examples of microtubule-based pushing and pulling in living cells have been observed, it is not clear why different cell types and processes employ different mechanisms. This review introduces a classification of microtubule-based positioning strategies and discusses the efficacy of pushing and pulling. The positioning mechanisms based on microtubule pushing are efficient for movements over small distances, and for centering of organelles in symmetric geometries. Mechanisms based on pulling, on the other hand, are typically more elaborate, but are necessary when the distances to be covered by the organelles are large, and when the geometry is asymmetric and complex. Thus, taking into account cell geometry and the length scale of the movements helps to identify general principles of the intracellular layout based on microtubule forces. PMID:18404264

  6. Non-paraxial beam to push and pull microparticles

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Qiu, C.-W.

    2011-01-01

    We discuss a feasibility of the pulling (backward) force acting on a spherical microparticle in a non-paraxial Bessel beam. The effect can be explained by the strong interaction of particle's multipoles or by the conservation of momentum in the system “photons-particle.” It is remarkable that the...

  7. A push-pull distraction method for arthroscopic subtalar joint arthrodesis.

    Science.gov (United States)

    Shibuya, Naohiro; Smith, Rebecca S; Escobedo, Laura A; Agarwal, Monica R

    2014-01-01

    Unlike ankle joint arthroscopy, distraction of the subtalar joint can be challenging. We introduce a powerful distraction method that can be used during an arthroscopic subtalar joint arthrodesis procedure using a "push-pull" technique. A fully threaded screw is used to push the talus while the calcaneus is pulled to distract the joint. The technique allows the surgeon to access the rather tight joint without disrupting a significant amount of the ligamentous and capsular structures. It also allows preservation of the vascular structures that supply the talus. The "push-pull" screw can also be converted to a second point of fixation at the end of the procedure. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Removal of Airborne Contaminants from a Surface Tank by a Push-Pull System

    DEFF Research Database (Denmark)

    Heiselberg, Per; Topp, Claus

    Open surface tanks are used in many industrial processes, and local exhaust systems are often designed to capture and remove toxic fumes diffused from materials in the tanks prior to their escape into the workplace environment. The push-pull system seems to be the most efficient local exhaust...... system, but proper design is required to ensure health and safety of the workers and, furthermore, it is very desirable from an energy conservation point of view to determine an optimum and -an efficient design of push-pull hoods which can exhaust all contaminants with a minimum quantity of volume flow....... The paper describes and discusses different design methods and compares designed values with results from a measurement series of push-pull system efficiency....

  9. Quality in the market : technology push versus market pull

    NARCIS (Netherlands)

    Luyten, H.

    2003-01-01

    To meet the changing demands of consumers, food technologists have to alter the way they are working. Instead of pushing new technologies and ingredients, they have to design the processes and formulations based on input from consumer, legal and nutritious wishes. This article presents a conceptual

  10. PUSH-PULL FACTORS IN MOUNTAIN RESORTS--A Case Study of Huangshan Mountain as World Heritage

    Institute of Scientific and Technical Information of China (English)

    WANG De-gen

    2004-01-01

    The push-pull framework provides a useful approach for examining the tourist motivation. This paper takes the world heritage-Huangshan Mountain as a sample. From the two different aspects of pull and push factors, the underlying features of visitors' motives to Huangshan Mountain are analyzed with the help of factor analysis. As a result,five push factors and four pull factors are identified. Further analyses investigate differences in the push and pull factors among different socio-demographic subgroups with one-way ANOVA analysis. The result of the study affords us useful references for development, protection and marketing expansion of mountain resorts.

  11. Smart windows using polymer-networked liquid crystals doped with push-pull azobenzene

    Science.gov (United States)

    Oh, Seung-Won; Baek, Jong-Min; Kim, Sang-Hyeok; Yoon, Tae-Hoon

    2017-02-01

    We propose a smart window using polymer-networked liquid crystals doped with push-pull azobenzene. Azobenzene is used to provide phase transition from the nematic to isotropic state through the trans-cis isomerization of azobenzene. When exposed to sunlight, the device switches from the opaque nematic phase to the transparent isotropic phase. Switching from the transparent to opaque state can be obtained through rapid cis-trans isomerization of push-pull azobenzene without sunlight exposure. The proposed device can reduce the transmittance of the incident sunlight during daytime, whereas it can scatter the incident light during the night for privacy.

  12. Pushing versus pulling: division of labour between tarsal attachment pads in cockroaches.

    Science.gov (United States)

    Clemente, Christofer J; Federle, Walter

    2008-06-07

    Adhesive organs on the legs of arthropods and vertebrates are strongly direction dependent, making contact only when pulled towards the body but detaching when pushed away from it. Here we show that the two types of attachment pads found in cockroaches (Nauphoeta cinerea), tarsal euplantulae and pretarsal arolium, serve fundamentally different functions. Video recordings of vertical climbing revealed that euplantulae are almost exclusively engaged with the substrate when legs are pushing, whereas arolia make contact when pulling. Thus, upward-climbing cockroaches used front leg arolia and hind leg euplantulae, whereas hind leg arolia and front leg euplantulae were engaged during downward climbing. Single-leg friction force measurements showed that the arolium and euplantulae have an opposite direction dependence. Euplantulae achieved maximum friction when pushed distally, whereas arolium forces were maximal during proximal pulls. This direction dependence was not explained by the variation of shear stress but by different contact areas during pushing or pulling. The changes in contact area result from the arrangement of the flexible tarsal chain, tending to detach the arolium when pushing and to peel off euplantulae when in tension. Our results suggest that the euplantulae in cockroaches are not adhesive organs but 'friction pads', mainly providing the necessary traction during locomotion.

  13. DEMAND PULL AND SUPPLY PUSH IN PORTUGUESE CABLE TELEVISION

    OpenAIRE

    João Leitão

    2004-01-01

    In this paper a Vector Autoregressive Model is applied to the most representative Portuguese cable television operators, in order to obtain a dynamic analysis of the interactivity established between the supply and the demand of network services, through the strategy of vertical integration of services. The results reveal the existence of two driving forces in the Portuguese main cable networks, on the one hand, the supply push which contributes to the enhancement of the basic cable demand, a...

  14. Mechanical loading of the low back and shoulders during pushing and pulling activities

    NARCIS (Netherlands)

    Hoozemans, Marco J M; Kuijer, P Paul F M; Kingma, Idsart; van Dieën, Jaap H; de Vries, Wiebe H K; van der Woude, Luc H V; Veeger, Dirk Jan H E J; van der Beek, Allard J; Frings-Dresen, Monique H W

    2004-01-01

    The objective of this study was to quantify the mechanical load on the low back and shoulders during pushing and pulling in combination with three task constraints: the use of one or two hands, three cart weights, and two handle heights. The second objective was to explore the relation between the i

  15. Laboratory evaluation techniques to investigate the spatial potential of repellents for push & pull mosquito control systems

    Science.gov (United States)

    A protocol has been developed for the indoor evaluation of candidate spatial repellents intended for use in push and pull systems. Single treatments (catnip oil, 1-methylpiperazine and homopiperazine) and a mixture of catnip oil and homopiperazine were tested with yellow-fever mosquitoes (Aedes aegy...

  16. A push-pull system to reduce house entry of malaria mosquitoes

    NARCIS (Netherlands)

    Menger, D.J.; Otieno, B.; Rijk, de M.; Mukabana, W.R.; Loon, van J.J.A.; Takken, W.

    2014-01-01

    Background. Mosquitoes are the dominant vectors of pathogens that cause infectious diseases such as malaria, dengue, yellow fever and filariasis. Current vector control strategies often rely on the use of pyrethroids against which mosquitoes are increasingly developing resistance. Here, a push-pull

  17. Engineering perspective on the evolution of push/pull-based dialysis treatments.

    Science.gov (United States)

    Lee, Kyungsoo

    2013-09-01

    The incidence of kidney disease is rapidly increasing worldwide, and techniques and devices for treating end-stage renal disease (ESRD) patients have been evolving. Better outcomes achieved by convective treatment have encouraged the use of synthetic membranes with high water permeability in clinical setups, and high-flux hemodialysis (HD) and hemodiafiltration (HDF) are now preferred forms of convective therapy in ESRD patients. Push/pull-based dialysis strategies have also been examined to increase convective mass transfer in ESRD patients. The push/pull technique uses the entire membrane as a forward filtration domain for a period of time. However, backfiltration must accompany the forward filtration to compensate for the fluid depletion resulting from the forward filtration, making it necessary to switch the membranes to a backfiltration domain. This paper attempts to describe the advancement of push/pull-based renal supportive treatments in terms of their technical description, hemodialytic efficacy including fluid management accuracy and applicability for clinical use. How the optimization of push and pull actions could translate into better convective efficiency will also be discussed in depth.

  18. Push and pull: Exposure of young Taiwanese women to sexually explicit materials.

    Science.gov (United States)

    Tseng, Ying-Hua; Esposito, Noreen; Kuo, Shih-Hsien; Chou, Fan-Hao; Cheng, Mei-Li

    2017-08-01

    This study was designed to understand young Taiwanese women's perception of sexually explicit materials (SEMs). Researchers conducted six focus group discussions with 38 young women between the ages of 18 and 22 in Taiwan in 2009-2010 and used content analysis to analyze the data based on the push-pull theory. The results showed that the exposure of young women to SEMs was a sexual exploration process from no sexual activity to future sexual activity. This process was affected by the interactions of three powers: push power, pull power, and personal factors. The push power included factors, such as parents and social values, which failed to satisfy their sexual curiosity and provide them with autonomy. The pull power included SEMs and peer influence, which increased sexual arousal stimuli and curiosity to try sexual activity. The most important personal factors were young women's growth, including sexual curiosity, cognition of SEMs, and gender equity in freedom to make sexual decisions. Understanding this push-pull process regarding SEM can help health-care providers with their own discourses in addressing sex and influence young women's participation in desired, protected, and enjoyable sex when sufficiently ready.

  19. Relation between Nonlinear Optical Properties of Push-Pull Molecules and Metric of Charge Transfer Excitations.

    Science.gov (United States)

    List, Nanna Holmgaard; Zaleśny, Robert; Murugan, N Arul; Kongsted, Jacob; Bartkowiak, Wojciech; Ågren, Hans

    2015-09-08

    We establish the relationships between the metric of charge transfer excitation (Δr) for the bright ππ* state and the two-photon absorption probability as well as the first hyperpolarizability for two families of push-pull π-conjugated systems. As previously demonstrated by Guido et al. (J. Chem. Theory Comput. 2013, 9, 3118-3126), Δr is a measure for the average hole-electron distance upon excitation and can be used to discriminate between short- and long-range electronic excitations. We indicate two new benefits from using this metric for the analyses of nonlinear optical properties of push-pull systems. First, the two-photon absorption probability and the first hyperpolarizability are found to be interrelated through Δr; if β ∼ (Δr)(k), then roughly, δ(TPA) ∼ (Δr)(k+1). Second, a simple power relation between Δr and the molecular hyperpolarizabilities of push-pull systems offers the possibility of estimating properties for longer molecular chains without performing calculations of high-order response functions explicitly. We further demonstrate how to link the hyperpolarizabilities with the chain length of the push-pull π-conjugated systems through the metric of charge transfer.

  20. Control and Modeling of Push-Pull Forward Three-Level Converter for Microgrid

    DEFF Research Database (Denmark)

    Yao, Zhilei; Xu, Jing; Guerrero, Josep M.

    2015-01-01

    Renewable energy sources are widely used in microgrid. Output voltage of them is often low and varies widely. Because diodes in three-level legs in traditional three-level (TL) converter are substituted by MOSFETs, the push-pull forward (PPF) TL converter is very suitable for wide and low...

  1. A push-pull system to reduce house entry of malaria mosquitoes

    NARCIS (Netherlands)

    Menger, D.J.; Otieno, B.; Rijk, de M.; Mukabana, W.R.; Loon, van J.J.A.; Takken, W.

    2014-01-01

    Background. Mosquitoes are the dominant vectors of pathogens that cause infectious diseases such as malaria, dengue, yellow fever and filariasis. Current vector control strategies often rely on the use of pyrethroids against which mosquitoes are increasingly developing resistance. Here, a push-pull

  2. Three Levels of Push-Pull Dynamics among Chinese International Students' Decision to Study Abroad in the Canadian Context

    Science.gov (United States)

    Chen, Jun Mian

    2017-01-01

    The extant literature on student migration flows generally focus on the traditional push-pull factors of migration at the individual level. Such a tendency excludes the broader levels affecting international student mobility. This paper proposes a hybrid of three levels of push-pull dynamics (micro-individual decision-making, meso-academic…

  3. Expediting P2P Video Delivery through a Hybrid Push-Pull Protocol

    Directory of Open Access Journals (Sweden)

    LEE, C.

    2015-11-01

    Full Text Available Despite the recent phenomenal success of peer-to-peer video streaming services, their stumbling performance for high-quality videos remains a major obstacle to wider acceptance. This is because high-resolution videos instantly delivered over the Internet are increasingly becoming the norm. This paper presents a novel solution to keep up with ever more challenging QoE expectations. Our proposal of a hybrid push-pull protocol consists of two key components, namely, a new push strategy and an elastic window scheme. The former empowers the hybrid protocol to make an informed push-pull decision based on chunk status and network condition, whereas the latter ensures balance between the two conflicting goals of chunk dissemination and playback deadline. The efficacy of the proposed protocol is validated through a performance study that demonstrates substantial gains compared to existing approaches.

  4. Effect of a powered drive on pushing and pulling forces when transporting bariatric hospital beds.

    Science.gov (United States)

    Wiggermann, Neal

    2017-01-01

    Powered drives designed to assist with moving hospital beds are commercially available but no studies have evaluated whether they reduce the push and pull forces likely contributing to injury in caregivers. This study measured hand forces of 10 caregivers maneuvering a manual and powered bariatric bed through simulated hospital environments (hallway, elevator, and ramp). Peak push and pull forces exceeded previously established psychophysical limits for all activities with the manual bed. For the powered bed, peak forces were significantly (p forces between 38% (maneuvering into elevator) and 94% (descending ramp). Powered drive also reduced stopping distance by 55%. When maneuvering, the integral of hand force was 34% lower with powered drive, but average forces during straight-line pushing did not differ between beds. Powered drive may reduce the risk of injury or the number of caregivers needed for transport. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Understanding the mechanism of B(12)-dependent diol dehydratase: a synergistic retro-push--pull proposal.

    Science.gov (United States)

    Smith, D M; Golding, B T; Radom, L

    2001-02-28

    Ab initio molecular orbital theory is used to investigate the coenzyme B(12)-dependent reactions catalyzed by diol dehydratase. The key step in such reactions is believed to be a 1,2-hydroxyl migration, which occurs within free-radical intermediates. The barrier for this migration, if unassisted, is calculated to be too high to be consistent with the observed reaction rate. However, we find that "pushing" the migrating hydroxyl, through interaction with a suitable acid, is able to provide significant catalysis. This is denoted retro-push catalysis, the retro prefix signifying that the motion of the migrating group is in the direction opposite to the electron motion. Similarly, the "pulling" of the migrating group, through interaction of the spectator hydroxyl with an appropriate base, is found to substantially reduce the rearrangement barrier. Importantly, the combination of these two effects results in a barrier reduction that is notably greater than additive. This synergistic interplay of the push and the pull provides an attractive means of catalysis. Our proposed retro-push--pull mechanism leads to results that are consistent with isotope-labeling experiments, with experimental rate data, and with the crystal structure of the enzyme.

  6. Push&Pull: autonomous deployment of mobile sensors for a complete coverage

    CERN Document Server

    Bartolini, N; Fusco, E G; Massini, A; Silvestri, S

    2008-01-01

    In this paper we propose a fully distributed algorithm for autonomous deployment of mobile sensors called Push&Pull, which is based on the interleaved execution of four basic activities. According to our proposal, movement decisions are made by each sensor on the basis of locally available information and do not require any prior knowledge of the operating conditions nor any manual tuning of key parameters. We prove that, unlike previous proposals, our approach guarantees a complete coverage, provided that a sufficient number of sensors are available. Furthermore, we demonstrate that the algorithm execution always terminates preventing movement oscillations. Extensive simulations show that our algorithm reaches a complete coverage within reasonable time with moderate energy consumption, even when the target area has irregular shapes. Performance comparisons between Push&Pull and one of the most acknowledged algorithms show how the former can reach a more uniform and complete coverage under a wide rang...

  7. Three-dimensional finite-element simulation of a turbulent push-pull ventilation system.

    Science.gov (United States)

    Flynn, M R; Ahn, K; Miller, C T

    1995-10-01

    A finite-element formulation with penalty approach to enforce continuity is employed here to simulate the three-dimensional velocity field resulting from a simple push-pull ventilation configuration. An analytic expression for the length scale and a transport equation for turbulent kinetic energy are coupled with the momentum equations. A coaxial square hood and jet are arranged with cross-draught perpendicular to the common centreline. Numerical predictions of the velocity and turbulence kinetic energy fields are evaluated in the plane of symmetry with hot film anemometry, and smoke-wire flow visualizations. The agreement of the simulated jet trajectories with flow visualizations is reasonable, as are velocities. Predictions of turbulence kinetic energy are not as good, particularly near the hood face. Despite the limitations the numerical approach is useful in assessing the impact of cross-draughts on the push-pull arrangement.

  8. Push-you-pull-you: the boundaried self in close relationships.

    Science.gov (United States)

    Rempel, John K; Burris, Christopher T

    2006-02-01

    Based on Amoebic Self Theory, the authors propose that the salience of different threats to the self affects the extent to which an intimate relationship partner is pushed away (excluded) or pulled closer (included). When social threat is salient among persons in relationships, it is hypothesized that partners will attempt to defuse the resulting sense of interpersonal vulnerability: offending partners may be pushed away, whereas offenders themselves may draw closer. When spatial-symbolic threat is salient and the relationship's capacity to function as an identity marker is jeopardized, it is hypothesized that the partner--regardless of his or her role--will be pulled closer to maintain the perception that the relationship is secure. Self-report responses to hypothetical scenarios and perceptions of behaviors during a role-play were generally consistent with these hypotheses, suggesting that both an intimate partner and the relationship with that partner can be incorporated into the self.

  9. Alphabet-Inspired Design of (Hetero)Aromatic Push-Pull Chromophores.

    Science.gov (United States)

    Klikar, Milan; Solanke, Parmeshwar; Tydlitát, Jiří; Bureš, Filip

    2016-08-01

    Push-pull molecules represent a unique and fascinating class of organic π-conjugated materials. Herein, we provide a summary of their recent extraordinary design inspired by letters of the alphabet, especially focusing on H-, L-, T-, V-, X-, and Y-shaped molecules. Representative structures from each class were presented and their fundamental properties and prospective applications were discussed. In particular, emphasis is given to molecules recently prepared in our laboratory with T-, X-, and Y-shaped arrangements based on indan-1,3-dione, benzene, pyridine, pyrazine, imidazole, and triphenylamine. These push-pull molecules turned out to be very efficient charge-transfer chromophores with tunable properties suitable for second-order nonlinear optics, two-photon absorption, reversible pH-induced and photochromic switching, photocatalysis, and intercalation.

  10. Push pull microfluidics on a multi-level 3D CD.

    Science.gov (United States)

    Thio, Tzer Hwai Gilbert; Ibrahim, Fatimah; Al-Faqheri, Wisam; Moebius, Jacob; Khalid, Noor Sakinah; Soin, Norhayati; Kahar, Maria Kahar Bador Abdul; Madou, Marc

    2013-08-21

    A technique known as thermo-pneumatic (TP) pumping is used to pump fluids on a microfluidic compact disc (CD) back towards the CD center against the centrifugal force that pushes liquids from the center to the perimeter of the disc. Trapped air expands in a TP air chamber during heating, and this creates positive pressure on liquids located in chambers connected to that chamber. While the TP air chamber and connecting channels are easy to fabricate in a one-level CD manufacturing technique, this approach provides only one way pumping between two chambers, is real-estate hungry and leads to unnecessary heating of liquids in close proximity to the TP chamber. In this paper, we present a novel TP push and pull pumping method which allows for pumping of liquid in any direction between two connected liquid chambers. To ensure that implementation of TP push and pull pumping also addresses the issue of space and heating challenges, a multi-level 3D CD design is developed, and localized forced convection heating, rather than infra-red (IR) is applied. On a multi-level 3D CD, the TP features are placed on a top level separate from the rest of the microfluidic processes that are implemented on a lower separate level. This approach allows for heat shielding of the microfluidic process level, and efficient usage of space on the CD for centrifugal handling of liquids. The use of localized forced convection heating, rather than infra-red (IR) or laser heating in earlier implementations allows not only for TP pumping of liquids while the CD is spinning but also makes heat insulation for TP pumping and other fluidic functions easier. To aid in future implementations of TP push and pull pumping on a multi-level 3D CD, study on CD surface heating is also presented. In this contribution, we also demonstrate an advanced application of pull pumping through the implementation of valve-less switch pumping.

  11. [How to do an effective literature search? The use of Push and Pull strategies].

    Science.gov (United States)

    Donato, Helena; Marinho, Rui Tato

    2013-01-01

    The availability of scientific information is growing exponentially. Healthcare professionals who wish to keep up-to-date with scientific literature and find the best information should spend their time finding resources that summarize the best available evidence. This manuscript aims to provide bibliographic research knowledge and skills, to contribute to an increase in the use of e-learning, to "Push and Pull" correct information and, in other words, to indicate how to deal with information overload.

  12. Push Pull Services Offering SMS Based m-Banking System in Context of Bangladesh

    Directory of Open Access Journals (Sweden)

    Fouzia Mousumi

    2010-01-01

    Full Text Available m-Banking technology has become one of the most familiar banking features throughout the world. Nowadaysmillions of inhabitants of Bangladesh are within a network through mobile network coverage. But in the commercial sectorslike banking, m-Commerce technology has not been adopted broadly yet. In context of Bangladesh where almost 95% ofgeographical areas including Chittagong Hill tract region is under cellular coverage and having insufficiency in Internetinfrastructure in remote regions, m-Banking via mobile phones can be the right choice for the promising banking sector.Considering m-Commerce and m-Banking perspective in Bangladesh, a Push Pull services offering SMS (Short MessagingService based m-Banking system has been proposed which is able to provide several essential banking services only bysending SMS to bank server from any remote location. This proposed system is divided into five major phases: InterfacingModule, SMS Technology Adoption Module, SMS Banking Registration Module, Push Pull m-Banking Services GenerationModule, and Modified Data Failover Module. This push-pull services specified system facilitates bank customers by carryingout real time m-Banking utilities by categorizing services into five major on the basis of their homogeneity. They areBroadcast, Scheduling, Event, Enquiry and m-Commerce services. Fifteen push pull services underlying these categories areimplemented in this proposed system which are most desired to customers. The proposed system not only brings bankingtransaction in hand’s grip but also makes it easier, robust and flexible with highest security. Moreover, modified data failoveralgorithm handles unexpected SMS server failure with any congestion or service request loss. At last, after evaluating eachmodule of our proposed system a satisfactory accuracy rate 94.95% has been obtained.

  13. Neglected infectious diseases: are push and pull incentive mechanisms suitable for promoting drug development research?

    Science.gov (United States)

    Mueller-Langer, Frank

    2013-04-01

    Infectious diseases are among the main causes of death and disability in developing countries, and they are a major reason for the health disparity between rich and poor countries. One of the reasons for this public health tragedy is a lack of lifesaving essential medicines, which either do not exist or badly need improvements. In this article, we analyse which of the push and pull mechanisms proposed in the recent literature may serve to promote research into neglected infectious diseases. A combination of push programmes that subsidise research inputs through direct funding and pull programmes that reward research output rather than research input may be the appropriate strategy to stimulate research into neglected diseases. On the one hand, early-stage (basic) research should be supported through push mechanisms, such as research grants or publicly financed research institutions. On the other hand, pull mechanisms, such as prize funds that link reward payments to the health impacts of effective medicines, have the potential to stimulate research into neglected diseases.

  14. Aerodynamic characteristics and design guidelines of push-pull ventilation systems.

    Science.gov (United States)

    Huang, R F; Lin, S Y; Jan, S-Y; Hsieh, R H; Chen, Y-K; Chen, C-W; Yeh, W-Y; Chang, C-P; Shih, T-S; Chen, C-C

    2005-01-01

    Aerodynamic characteristics such as the flow patterns, velocity field, streamline evolutions, characteristic flow modes and characteristic flow regimes of the push-pull ventilation system are cross-examined by using the laser-light sheet smoked-flow visualization method and laser Doppler velocimetry. Four characteristic flow modes, which are denoted as dispersion, transition, encapsulation and strong suction, are identified in the domain of the push-jet and pull-flow velocities at various open-surface tank widths and rising gas velocities. It is argued phenomenologically, from the aerodynamic point of view, that operating the system in the strong suction regime would be a better strategy than operating it in other characteristic regimes for the consideration of capture efficiency. Design guidelines are developed and summarized based on the results obtained from this study. The regression formulas for calculating the critical values of the push-jet and the pull-flow velocities are provided for easy access. The sulfur hexafluoride tracer gas validation technique is performed to measure the capture efficiency. The results of tracer gas validations are consistent with those obtained from the aerodynamic visualization and measurements. The operation points obtained by employing the American Conference of Governmental Industrial Hygienists design criteria are compared with the results obtained in this study for both the aerodynamics and the capture efficiency. Methods for improving the capture efficiency and energy consumptions are suggested.

  15. Field evaluation of a push-pull system to reduce malaria transmission.

    Science.gov (United States)

    Menger, David J; Omusula, Philemon; Holdinga, Maarten; Homan, Tobias; Carreira, Ana S; Vandendaele, Patrice; Derycke, Jean-Luc; Mweresa, Collins K; Mukabana, Wolfgang Richard; van Loon, Joop J A; Takken, Willem

    2015-01-01

    Malaria continues to place a disease burden on millions of people throughout the tropics, especially in sub-Saharan Africa. Although efforts to control mosquito populations and reduce human-vector contact, such as long-lasting insecticidal nets and indoor residual spraying, have led to significant decreases in malaria incidence, further progress is now threatened by the widespread development of physiological and behavioural insecticide-resistance as well as changes in the composition of vector populations. A mosquito-directed push-pull system based on the simultaneous use of attractive and repellent volatiles offers a complementary tool to existing vector-control methods. In this study, the combination of a trap baited with a five-compound attractant and a strip of net-fabric impregnated with micro-encapsulated repellent and placed in the eaves of houses, was tested in a malaria-endemic village in western Kenya. Using the repellent delta-undecalactone, mosquito house entry was reduced by more than 50%, while the traps caught high numbers of outdoor flying mosquitoes. Model simulations predict that, assuming area-wide coverage, the addition of such a push-pull system to existing prevention efforts will result in up to 20-fold reductions in the entomological inoculation rate. Reductions of such magnitude are also predicted when mosquitoes exhibit a high resistance against insecticides. We conclude that a push-pull system based on non-toxic volatiles provides an important addition to existing strategies for malaria prevention.

  16. Field evaluation of a push-pull system to reduce malaria transmission.

    Directory of Open Access Journals (Sweden)

    David J Menger

    Full Text Available Malaria continues to place a disease burden on millions of people throughout the tropics, especially in sub-Saharan Africa. Although efforts to control mosquito populations and reduce human-vector contact, such as long-lasting insecticidal nets and indoor residual spraying, have led to significant decreases in malaria incidence, further progress is now threatened by the widespread development of physiological and behavioural insecticide-resistance as well as changes in the composition of vector populations. A mosquito-directed push-pull system based on the simultaneous use of attractive and repellent volatiles offers a complementary tool to existing vector-control methods. In this study, the combination of a trap baited with a five-compound attractant and a strip of net-fabric impregnated with micro-encapsulated repellent and placed in the eaves of houses, was tested in a malaria-endemic village in western Kenya. Using the repellent delta-undecalactone, mosquito house entry was reduced by more than 50%, while the traps caught high numbers of outdoor flying mosquitoes. Model simulations predict that, assuming area-wide coverage, the addition of such a push-pull system to existing prevention efforts will result in up to 20-fold reductions in the entomological inoculation rate. Reductions of such magnitude are also predicted when mosquitoes exhibit a high resistance against insecticides. We conclude that a push-pull system based on non-toxic volatiles provides an important addition to existing strategies for malaria prevention.

  17. Are single-well "push-pull" tests suitable tracer methods for aquifer characterization?

    Science.gov (United States)

    Hebig, Klaus; Zeilfelder, Sarah; Ito, Narimitsu; Machida, Isao; Scheytt, Traugott; Marui, Atsunao

    2013-04-01

    Recently, investigations were conducted for geological and hydrogeological characterisation of the sedimentary coastal basin of Horonobe (Hokkaido, Japan). Coastal areas are typical geological settings in Japan, which are less tectonically active than the mountain ranges. In Asia, and especially in Japan, these areas are often densely populated. Therefore, it is important to investigate the behaviour of solutes in such unconsolidated aquifers. In such settings sometimes only single boreholes or groundwater monitoring wells are available for aquifer testing for various reasons, e.g. depths of more than 100 m below ground level and slow groundwater velocities due to density driven flow. A standard tracer test with several involved groundwater monitoring wells is generally very difficult or even not possible at these depths. One of the most important questions in our project was how we can obtain information about chemical and hydraulic properties in such aquifers. Is it possible to characterize solute transport behaviour parameters with only one available groundwater monitoring well or borehole? A so-called "push-pull" test may be one suitable method for aquifer testing with only one available access point. In a push-pull test a known amount of several solutes including a conservative tracer is injected into the aquifer ("push") and afterwards extracted ("pull"). The measured breakthrough curve during the pumping back phase can then be analysed. This method has already been used previously with various aims, also in the recent project (e.g. Hebig et al. 2011, Zeilfelder et al. 2012). However, different test setups produced different tracer breakthrough curves. As no systematic evaluation of this aquifer tracer test method was done so far, nothing is known about its repeatability. Does the injection and extraction rate influence the shape of the breakthrough curve? Which role plays the often applied "chaser", which is used to push the test solution out from the

  18. Design and statistical optimization of osmotically driven capsule based on push-pull technology.

    Science.gov (United States)

    Shaikh, Wasim; Deshmukh, Prashant K; Patil, Ganesh B; Chatap, Vivekanand K; Bari, Sanjay B

    2013-01-01

    In present investigation attempt was made to develop and statistically optimize osmotically active capsule tailor made from the concept of bilayer (push-pull) osmotic tablet technology. The capsule was comprised of active (drug) and push (osmogen) layer. Active layer was compressed in form of tablet by mixing known amount of drug and formulation excipients. Similarly push layer was made by compressing Mannitol with formulation excipients. Finally, both layers were packed in hard gelatin capsule having small aperture at top and coated with semipermeable membrane to form osmotically active capsule. Formulated and optimized capsules were characterized for Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetric (DSC), scanning electron microscopy, In-vitro drug release study and Release models and kinetics. Statistically optimized formulation showed good correlation between predicted and experimented results, which further confirms the practicability and validity of the model.

  19. Pulled in or pushed out? Understanding the complexities of motivation for alternative therapies use in Ghana.

    Science.gov (United States)

    Gyasi, Razak Mohammed; Asante, Felix; Yeboah, Joseph Yaw; Abass, Kabila; Mensah, Charlotte Monica; Siaw, Lawrencia Pokuah

    2016-01-01

    The impact of strong cultural beliefs on specific reasons for traditional medicine (TRM) use among individuals and populations has long been advanced in health care and spatio-medical literature. Yet, little has been done in Ghana and the Ashanti Region in particular to bring out the precise "pull" and "push" relative influences on TRM utilization. With a qualitative research approach involving rural and urban character, the study explored health beliefs and motivations for TRM use in Kumasi Metropolis and Sekyere South District, Ghana. The study draws on data from 36 in-depth interviews with adults, selected through theoretical sampling. We used the a posteriori inductive reduction model to derive broad themes and subthemes. The "pull factors"-perceived benefits in TRM use vis-à-vis the "push factors"-perceived poor services of the biomedical treatments contributed to the growing trends in TRM use. The result however indicates that the "pull factors," viz.-personal health beliefs, desire to take control of one's health, perceived efficacy, and safety of various modalities of TRM-were stronger in shaping TRM use. Poor access to conventional medicine accounted for the differences in TRM use between rural and urban areas. Understanding the treatment and health-seeking behaviour of a cultural-related group is critical for developing and sustaining traditional therapy in Ghana.

  20. Fast Singlet Exciton Decay in Push-Pull Molecules Containing Oxidized Thiophenes.

    Science.gov (United States)

    Busby, Erik; Xia, Jianlong; Low, Jonathan Z; Wu, Qin; Hoy, Jessica; Campos, Luis M; Sfeir, Matthew Y

    2015-06-18

    A common synthetic strategy used to design low-bandgap organic semiconductors employs the use of "push-pull" building blocks, where electron -rich and electron-deficient monomers are alternated along the π-conjugated backbone of a molecule or polymer. Incorporating strong "pull" units with high electron affinity is a means to further decrease the optical gap for infrared optoelectronics or to develop n-type semiconducting materials. Here we show that the use of thiophene-1,1-dioxide as a strong acceptor in "push-pull" oligomers affects the electronic structure and carrier dynamics in unexpected ways. Critically, the overall excited-state lifetime is reduced by several orders of magnitude relative to unoxidized analogs due to the introduction of low-energy optically dark states and low-energy triplet states that allow for fast internal conversion and intramolecular singlet fission. We found that the electronic structure and excited-state lifetime are strongly dependent on the number of sequential thiophene-1,1-dioxide units. These results suggest that both the static and dynamical optical properties are highly tunable via small changes in chemical structure that have drastic effects on the optoelectronic properties, which can impact the types of applications that involve these materials.

  1. Range expansions transition from pulled to pushed waves with increasing cooperativity in an experimental microbial population

    Science.gov (United States)

    Gandhi, Saurabh; Yurtsev, Eugene; Korolev, Kirill; Gore, Jeff

    Range expansions are becoming more frequent due to environmental changes and rare long distance dispersal, often facilitated by anthropogenic activities. Simple models in theoretical ecology explain many emergent properties of range expansions, such as a constant expansion velocity, in terms of organism-level properties such as growth and dispersal rates. Testing these quantitative predictions in natural populations is difficult because of large environmental variability. Here, we used a controlled microbial model system to study range expansions of populations with and without intra-specific cooperativity. For non-cooperative growth, the expansion dynamics were dominated by population growth at the low-density front, which pulled the expansion forward. We found these expansions to be in close quantitative agreement with the classical theory of pulled waves by Fisher and Skellam, suitably adapted to our experimental system. However, as cooperativity increased, the expansions transitioned to being pushed, i.e. controlled by growth in the bulk as well as in the front. Although both pulled and pushed waves expand at a constant velocity and appear otherwise similar, their distinct dynamics leads to very different evolutionary consequences. Given the prevalence of cooperative growth in nature, understanding the effects of cooperativity is essential to managing invading species and understanding their evolution.

  2. DEVELOPMENT AND EVALUATION OF PUSH-PULL BASED OSMOTIC DELIVERY SYSTEM FOR ROPINIROLE

    Directory of Open Access Journals (Sweden)

    Adarsh Shah et al

    2012-09-01

    Full Text Available Ropinirole hydrochloride is indicated in Parkinson’s disease and Restless leg syndrome. In advanced Parkinson’s disease the usual dose of Ropinirole hydrochloride is 0.25 to 5 mg three to four times a day. Hence, an attempt was made to develop a once-a-day controlled release Osmotic drug delivery system. This may offer significant patient benefits by providing enhanced efficacy and reduced side effects and may also reduce the number of daily doses compared to conventional therapies. An oral push-pull system that can deliver Ropinirole hydrochloride for extended period of time has been developed and characterized. A bilayer osmotic drug delivery system was developed using drilling technique. The push layer swells releasing the drug at a controlled rate. An optimized system was selected to study the effect of pH of dissolution medium and the effect of agitation intensity. The drug release was found to follow zero order kinetics. The developed push-pull osmotic system showed the desired once-a-day release kinetic.

  3. A push-pull system to reduce house entry of malaria mosquitoes.

    Science.gov (United States)

    Menger, David J; Otieno, Bruno; de Rijk, Marjolein; Mukabana, W Richard; van Loon, Joop J A; Takken, Willem

    2014-03-27

    Mosquitoes are the dominant vectors of pathogens that cause infectious diseases such as malaria, dengue, yellow fever and filariasis. Current vector control strategies often rely on the use of pyrethroids against which mosquitoes are increasingly developing resistance. Here, a push-pull system is presented, that operates by the simultaneous use of repellent and attractive volatile odorants. Experiments were carried out in a semi-field set-up: a traditional house which was constructed inside a screenhouse. The release of different repellent compounds, para-menthane-3,8-diol (PMD), catnip oil e.o. and delta-undecalactone, from the four corners of the house resulted in significant reductions of 45% to 81.5% in house entry of host-seeking malaria mosquitoes. The highest reductions in house entry (up to 95.5%), were achieved by simultaneously repelling mosquitoes from the house (push) and removing them from the experimental set-up using attractant-baited traps (pull). The outcome of this study suggests that a push-pull system based on attractive and repellent volatiles may successfully be employed to target mosquito vectors of human disease. Reductions in house entry of malaria vectors, of the magnitude that was achieved in these experiments, would likely affect malaria transmission. The repellents used are non-toxic and can be used safely in a human environment. Delta-undecalactone is a novel repellent that showed higher effectiveness than the established repellent PMD. These results encourage further development of the system for practical implementation in the field.

  4. Second- and third-order nonlinearities of novel push-pull azobenzene polymers.

    Science.gov (United States)

    El Ouazzani, Hasnaa; Iliopoulos, Konstantinos; Pranaitis, Mindaugas; Krupka, Oksana; Smokal, Vitaliy; Kolendo, Aleksey; Sahraoui, Bouchta

    2011-03-10

    In this work, the second- and third-order nonlinear optical response of spin-deposited thin films of three different push-pull side chain azobenzene polymers is investigated by the second- and third-harmonic Maker fringes techniques using 30 ps laser pulses at a fundamental wavelength of 1064 nm. Measurements were carried out before and after aligning the chromophores by corona poling of the films, while different polarization configurations have been utilized. Strong dependence of the response upon the structure of the systems has been found, which is related to the different charge transfer within the molecules. The reported findings are compared with already published results.

  5. Single-well "push-pull" partitioning tracer test for NAPL detection in the subsurface.

    Science.gov (United States)

    Istok, Jonathan D; Field, Jennifer A; Schroth, Martin H; Davis, Brian M; Dwarakanath, Varadarajan

    2002-06-15

    Previous environmental applications of partitioning tracer tests to detect and quantify nonaqueous phase liquid (NAPL) contamination in the subsurface have been limited to well-to-well tests. However, theory and numerical modeling suggests that single-well injection-extraction ("push-pull") partitioning tracer tests can also potentially detect and quantify NAPL contamination. In this type of test, retardation factors for injected partitioning tracers are estimated from the increase in apparent dispersion observed in extraction-phase breakthrough curves in the presence of NAPL. A series of laboratory push-pull tests was conducted in physical aquifer models (PAMs) packed with natural aquifer sediment prepared with and without the presence of trichloroethene (TCE) NAPL. Field tests were conducted in an aquifer contaminated with petroleum hydrocarbon NAPL. Injected test solutions contained a suite of partitioning and conservative (nonpartitioning) alcohol tracers. Laboratory push-pull partitioning tracer tests were able to detect and quantify sorption of partitioning tracers to aquifer sediment (in the absence of NAPL) and to detect NAPL when it was present. NAPL saturations computed from estimated retardation factors bracketed those computed from known volumes of emplaced NAPL in the sediment pack. However, numerical modeling with assumed homogeneous NAPL distribution and linear equilibrium partitioning of tracers between aqueous and NAPL phases was unable to reproduce all features of observed breakthrough curves. Excavation of the sediment pack after all tests indicated that a portion of the emplaced NAPL had sunk to the bottom of the PAM invalidating the modeling assumption of homogeneous NAPL distribution. Moreover, the apparent dispersion in extraction-phase breakthrough curves decreased when the injection-extraction pumping rate was decreased, suggesting that mass transfer limitations existed during laboratory tests. Field push-pull partitioning tracer tests were

  6. An Optimal Pull-Push Scheduling Algorithm Based on Network Coding for Mesh Peer-to-Peer Live Streaming

    Science.gov (United States)

    Cui, Laizhong; Jiang, Yong; Wu, Jianping; Xia, Shutao

    Most large-scale Peer-to-Peer (P2P) live streaming systems are constructed as a mesh structure, which can provide robustness in the dynamic P2P environment. The pull scheduling algorithm is widely used in this mesh structure, which degrades the performance of the entire system. Recently, network coding was introduced in mesh P2P streaming systems to improve the performance, which makes the push strategy feasible. One of the most famous scheduling algorithms based on network coding is R2, with a random push strategy. Although R2 has achieved some success, the push scheduling strategy still lacks a theoretical model and optimal solution. In this paper, we propose a novel optimal pull-push scheduling algorithm based on network coding, which consists of two stages: the initial pull stage and the push stage. The main contributions of this paper are: 1) we put forward a theoretical analysis model that considers the scarcity and timeliness of segments; 2) we formulate the push scheduling problem to be a global optimization problem and decompose it into local optimization problems on individual peers; 3) we introduce some rules to transform the local optimization problem into a classical min-cost optimization problem for solving it; 4) We combine the pull strategy with the push strategy and systematically realize our scheduling algorithm. Simulation results demonstrate that decode delay, decode ratio and redundant fraction of the P2P streaming system with our algorithm can be significantly improved, without losing throughput and increasing overhead.

  7. Transformation from a Single Antenna to a Series Array Using Push/Pull Origami

    Directory of Open Access Journals (Sweden)

    Syed Imran Hussain Shah

    2017-08-01

    Full Text Available We propose a push/pull origami antenna, transformable between a single antenna element and a three-element array. In limited space, the proposed origami antenna can work as a single antenna. When the space is not limited and a higher gain is required, the proposed origami antenna can be transformed to a series antenna array by pulling the frame. In order to push the antenna array back to a single antenna, the frame for each antenna element size must be different. The frame and supporting dielectric materials are built using a three-dimensional (3D printer. The conductive patterns are inkjet-printed on paper. Thus, the proposed origami antenna is built using hybrid printing technology. The 10-dB impedance bandwidth is 2.5–2.65 GHz and 2.48–2.62 GHz for the single-antenna and array mode, respectively, and the peak gains in the single-antenna and array mode are 5.8 dBi and 7.6 dBi, respectively. The proposed antenna can be used for wireless remote-sensing applications.

  8. Ladderlike oligomers; intramolecular hydrogen bonding, push-pull character, and electron affinity.

    Science.gov (United States)

    Pieterse, K; Vekemans, J A; Kooijman, H; Spek, A L; Meijer, E W

    2000-12-15

    Symmetrical 2,5-bis(2-aminophenyl)pyrazines have been synthesized by application of the Stille coupling strategy. These cotrimers feature three important properties, namely strong intramolecular hydrogen bonding, push-pull character, and high electron affinity. The presence of intramolecular hydrogen bonds has been confirmed by 1H NMR, IR spectroscopy, and single-crystal X-ray diffraction. The hydrogen bond strength can be increased by substituting the amino groups with stronger electron-withdrawing functionalities. Despite the anticipated enhanced pi-conjugation through planarization, a hypsochromic shift was observed in the UV/Vis spectra, explained by a decrease in push-pull character. The electron affinity of the cotrimers was deduced from the first reduction potentials measured by cyclic voltammetry and is related to the electron-withdrawing character of the amino substituents. The results obtained have been compared with those of the corresponding 4-aminophenyl analogues and show that intramolecular hydrogen bonds can be used to design polymers with enhanced pi conjugation as well as a high electron affinity.

  9. Push, pull, and plant: the personal side of physician immigration to alberta, Canada.

    Science.gov (United States)

    Klein, Douglas; Hofmeister, Marianna; Lockyear, Jocelyn; Crutcher, Rodney; Fidler, Herta

    2009-03-01

    The global migration of physicians has led many international physicians to enter practice in Alberta, Canada. The study was designed to explore the personal side of migration and transition experiences of these international medical graduates (IMGs). A qualitative study using telephone interviews and a semi-structured interview guide was used to interview 19 IMGs who are currently practicing and have held Part V, restricted or temporary practice licenses for less than 7 years. Three major themes were identified. The first was the "push" from their own country of origin and their perception that moving to Alberta would be better for them. Professional opportunities in their home country had been affected by changing policies, lack of infrastructure, and personal/family safety issues culminating in highly stressful work environments. The second was "pull." An improvement in the quality of personal life was associated with geographical, educational, recreational, and spiritual aspects of daily living for participants and their families in their new environment. The third theme was "plant"ie, factors that encouraged them to stay in Alberta. This study demonstrates the continued relevance of push and pull theory in understanding IMG physician migration. Our findings in this study indicate that remaining in place, or "being planted" is conditional on political, social, and economic aspects.

  10. Porphyrin Donor and Tunable Push-Pull Acceptor Conjugates-Experimental Investigation of Marcus Theory.

    Science.gov (United States)

    Reekie, Tristan A; Sekita, Michael; Urner, Lorenz M; Bauroth, Stefan; Ruhlmann, Laurent; Gisselbrecht, Jean-Paul; Boudon, Corinne; Trapp, Nils; Clark, Timothy; Guldi, Dirk M; Diederich, François

    2017-05-05

    We report on a series of electron donor-acceptor conjugates incorporating a Zn(II) -porphyrin-based electron donor and a variety of non-conjugated rigid linkers connecting to push-pull chromophores as electron acceptors. The electron acceptors comprize multicyanobutadienes or extended tetracyanoquinodimethane analogues with first reduction potentials ranging from -1.67 to -0.23 V vs. Fc(+) /Fc in CH2 Cl2 , which are accessible through a final-step cycloaddition-retroelectrocyclization (CA-RE) reaction. Characterization of the conjugates includes electrochemistry, spectroelectrochemistry, DFT calculations, and photophysical measurements in a range of solvents. The collected data allows for the construction of multiple Marcus curves that consider electron-acceptor strength, linker length, and solvent, with data points extending well into the inverted region. The enhancement of electron-vibration couplings, resulting from the rigid spacers and, in particular, multicyano-groups in the conformationally highly fixed push-pull acceptor chromophores affects the charge-recombination kinetics in the inverted region drastically. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Push-Pull Air Curtain Performances for VOCs Containment in an Industrial Process

    Directory of Open Access Journals (Sweden)

    A. Aubert

    2011-01-01

    Full Text Available The aim of this study is to analyze the efficiency of a Volatile Organic Compounds (VOCs containment system using an air curtain (push-pull type on a manual workstation. This work combines CFD numerical simulations of the air curtain system and experimental studies on a real scale test bench. The point is to evaluate whether the actual worker protection can be replaced by an air curtain system, without weakening human safety. The new system could considerably reduce energetic consumption (ventilation, heating and VOCs emissions into the atmosphere. Experimental studies of the flow using a Particle Image Velocimetry anemometer (PIV have been carried out to validate the numerical model kinematics. The containment quality obtained by the model has been validated with experimental concentration fields given by a gaseous analyzer using flame ionization (FID. Numerical simulation provides an overview of the containment efficiency in the global area of the system. Thus, it is possible to evaluate numerically, but accurately, the quality of the containment of the system. Moreover, an energetic study proves the economic benefit of the push-pull system.

  12. Transformation from a Single Antenna to a Series Array Using Push/Pull Origami.

    Science.gov (United States)

    Shah, Syed Imran Hussain; Lim, Sungjoon

    2017-08-26

    We propose a push/pull origami antenna, transformable between a single antenna element and a three-element array. In limited space, the proposed origami antenna can work as a single antenna. When the space is not limited and a higher gain is required, the proposed origami antenna can be transformed to a series antenna array by pulling the frame. In order to push the antenna array back to a single antenna, the frame for each antenna element size must be different. The frame and supporting dielectric materials are built using a three-dimensional (3D) printer. The conductive patterns are inkjet-printed on paper. Thus, the proposed origami antenna is built using hybrid printing technology. The 10-dB impedance bandwidth is 2.5-2.65 GHz and 2.48-2.62 GHz for the single-antenna and array mode, respectively, and the peak gains in the single-antenna and array mode are 5.8 dBi and 7.6 dBi, respectively. The proposed antenna can be used for wireless remote-sensing applications.

  13. Micro push-pull tests under unsaturated conditions: A new technique to investigate rhizosphere processes

    Science.gov (United States)

    Knecht, Kajsa; Nowack, Bernd; Schroth, Martin Herbert; Schulin, Rainer

    2010-05-01

    The rhizosphere differs in many aspects from the bulk soil. The growth of roots or uptake of water by plants alters directly the physical properties of the rhizosphere. Root activities such as absorption, respiration or exudation can change many chemical properties in the rhizosphere. The aim of this study is to develop a new micro technique that allows studying rhizosphere processes at microscopic scale in-situ. Our goal is to combine the technique of micro-suction cups with that of push-pull tests, creating a miniaturized system that is applicable to study not only concentrations but also reactions and exudation rates in the rhizosphere under conditions as undisturbed as possible. Push-pull tests have been used extensively on a larger scale for the investigation of chemical, physical and biological pollutant transport and transformation processes in aquifers. In a push-pull test, a solution containing reactive and non-reactive tracers is injected into a porous medium. After a defined time the test-solution/soilwater mixture is then extracted back from the same location. At first, we developed and validated a micro push-pull test procedure that works under saturated conditions in sand-filled boxes. It was possible to inject about 250 µl solution and extract 850 µl solution at a low and constant injection/extraction rate. The data were analyzed and successfully modeled considering advection, dispersion and molecular diffusion. Tracer concentrations of the extracted solution could be very well predicted without using any adjustable parameters. Molecular diffusion was found to play a significant role in determining the shape of the extraction curve. In a subsequent experiment using this technique, it was possible to quantify the degradation rate of citrate injected into a water-saturated, sand-filled box inoculated with denitrifying bacteria. The new technique thus proved to be an adequate tool to observe local biodegradation processes in situ. Now, we are

  14. Determinants and magnitudes of manual force strengths and joint moments during two-handed standing maximal horizontal pushing and pulling.

    Science.gov (United States)

    Chow, Amy Y; Dickerson, Clark R

    2016-04-01

    Pushing and pulling are common occupational exertions that are increasingly associated with musculoskeletal complaints. This study focuses on the sensitivity of shoulder capacity to gender, handle height, exertion type (push or pull) and handle orientation for these tasks. All factors except for handle orientation influenced unilateral and total manual force strength (p < 0.01), with exertion type being the most influential. Interaction effects also existed between handle height and exertion type. Additionally, joint moments at the shoulders and low back were influenced by all factors studied (p < 0.01), with exertion type again being most influential. Knowledge of the relative influence of multiple factors on shoulder capacity can provide guidance regarding these factors when designing or evaluating occupational pushing and pulling tasks for a diverse population. Practitioner Summary: pushing and pulling comprise nearly half of all manual materials handling tasks. Practitioners often assess, design or modify these tasks while incorporating constraints, including manual force direction and handle interface. This study provides guidance to aid design of pushing and pulling tasks in the context of shoulder physical capacity.

  15. Push-Pull: Chemical Ecology-Based Integrated Pest Management Technology.

    Science.gov (United States)

    Khan, Zeyaur; Midega, Charles A O; Hooper, Antony; Pickett, John

    2016-07-01

    Lepidopterous stemborers, and parasitic striga weeds belonging to the family Orobanchaceae, attack cereal crops in sub-Saharan Africa causing severe yield losses. The smallholder farmers are resource constrained and unable to afford expensive chemicals for crop protection. The push-pull technology, a chemical ecology- based cropping system, is developed for integrated pest and weed management in cereal-livestock farming systems. Appropriate plants were selected that naturally emit signaling chemicals (semiochemicals). Plants highly attractive for stemborer egg laying were selected and employed as trap crops (pull), to draw pests away from the main crop. Plants that repelled stemborer females were selected as intercrops (push). The stemborers are attracted to the trap plant, and are repelled from the main cereal crop using a repellent intercrop (push). Root exudates of leguminous repellent intercrops also effectively control the parasitic striga weed through an allelopathic mechanism. Their root exudates contain flavonoid compounds some of which stimulate germination of Striga hermonthica seeds, such as Uncinanone B, and others that dramatically inhibit their attachment to host roots, such as Uncinanone C and a number of di-C-glycosylflavones (di-CGFs), resulting in suicidal germination. The intercrop also improves soil fertility through nitrogen fixation, natural mulching, improved biomass, and control of erosion. Both companion plants provide high value animal fodder, facilitating milk production and diversifying farmers' income sources. The technology is appropriate to smallholder mixed cropping systems in Africa. Adopted by about 125,000 farmers to date in eastern Africa, it effectively addresses major production constraints, significantly increases maize yields, and is economical as it is based on locally available plants, not expensive external inputs.

  16. Experimental evaluation and computational modeling of tissue damage from low-flow push-pull perfusion sampling in vivo.

    Science.gov (United States)

    Cepeda, David E; Hains, Leah; Li, David; Bull, Joseph; Lentz, Stephen I; Kennedy, Robert T

    2015-03-15

    Neurochemical monitoring via sampling probes is valuable for deciphering neurotransmission in vivo. Microdialysis is commonly used; however, the spatial resolution is poor. Recently push-pull perfusion at low flow rates (50nL/min) has been proposed as a method for in vivo sampling from the central nervous system. Tissue damage from such probes has not been investigated in detail. In this work, we evaluated acute tissue response to low-flow push-pull perfusion by infusing the nuclear stains Sytox Orange and Hoechst 33342 through probes implanted in the striatum for 200min, to label damaged and total cells, respectively, in situ. Using the damaged/total labeled cell ratio as a measure of tissue damage, we found that 33±8% were damaged within the dye region around a microdialysis probe. We found that low-flow push-pull perfusion probes damaged 24±4% of cells in the sampling area. Flow had no effect on the number of damaged cells for low-flow push-pull perfusion. Modeling revealed that shear stress and pressure gradients generated by the flow were lower than thresholds expected to cause damage. Comparison with existing methods.Push-pull perfusion caused less tissue damage but yielded 1500-fold better spatial resolution. Push-pull perfusion at low flow rates is a viable method for sampling from the brain with potential for high temporal and spatial resolution. Tissue damage is mostly caused by probe insertion. Smaller probes may yield even lower damage. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Migrants in industrial zones - Push and pull factors. A case study in industrial zones in Bac Ninh province, Vietnam

    OpenAIRE

    Ngo Trung, Thanh; Lebailly, Philippe; Nguyen Thi, Dien

    2015-01-01

    Since migration was mentioned as a pattern of development, the debates have never ended. In Vietnam, the industrial zone has been developed rapidly for more than 20 years. However, the rate of migrant labor is high. Based on push and pull theory of migration the study is to find the reasons that push or pull rural labors to migrate to industrial zones. By surveying 190 migrants in industrial zone, the study found that the employment in the zones is not stable in the long run. Migration not al...

  18. Migrants in industrial zones - Push and pull factors. A case study in industrial zones in Bac Ninh province, Vietnam

    OpenAIRE

    Ngo Trung, Thanh; Lebailly, Philippe; Nguyen Thi, Dien

    2015-01-01

    Since migration was mentioned as a pattern of development, the debates have never ended. In Vietnam, the industrial zone has been developed rapidly for more than 20 years. However, the rate of migrant labor is high. Based on push and pull theory of migration the study is to find the reasons that push or pull rural labors to migrate to industrial zones. By surveying 190 migrants in industrial zone, the study found that the employment in the zones is not stable in the long run. Migration not al...

  19. What Makes International Capital Flows So Volatile?: Push vs. Pull Factors in the Case of Korea

    Directory of Open Access Journals (Sweden)

    Tae-Joon Kim

    2010-12-01

    Full Text Available This paper analyzes the determinants of financial capital flows in Korea, which provides an intriguing case for examining the volatility of such flows as an almost fully opened capital market. Our empirical analysis finds both pull and push factors have significantly affected all three types of foreign capital flows- foreign equity investment, foreign bond investment and foreign other-type investment- in Korea, though the relative importance of each factor varies by sample period and type of financial capital. First, the determinants of capital inflows changed substantially following the 1997 currency crisis. The impact of push factors on foreign investment strengthened, rendering the Korean stock and bond market more susceptible to external shocks. Second, the global financial crisis, which increased global financial instability and preference for safe assets, appears to have had a negative effect on other-type investment. However, fThis paper analyzes the determinants of financial capital flows in Korea, which provides an intriguing case for examining the volatility of such flows as an almost fully opened capital market. Our empirical analysis finds both pull and push factors have significantly affected all three types of foreign capital flows- foreign equity investment, foreign bond investment and foreign other-type investment- in Korea, though the relative importance of each factor varies by sample period and type of financial capital. First, the determinants of capital inflows changed substantially following the 1997 currency crisis. The impact of push factors on foreign investment strengthened, rendering the Korean stock and bond market more susceptible to external shocks. Second, the global financial crisis, which increased global financial instability and preference for safe assets, appears to have had a negative effect on other-type investment. However, foreign equity investment showed a quick recovery in the wake of global financial

  20. Determinants of FDI into Central and Eastern European Countries: Pull or Push Effect?

    Directory of Open Access Journals (Sweden)

    Burcak Polat

    2015-11-01

    Full Text Available Despite the growing interest in foreign direct investments (FDI, substantial uncertainty still exists regarding what stimulates foreign investors to operate in a foreign market and uneven distribution of FDI across countries. Using panel data for 2001 -2012 period, the major determinants of the FDI inflows into the Central and Eastern European Countries are analysed in this study. Strong evidence are found that while EU CR indices, EU and USA real GDP growth rates and global financial crisis have power to explain FDI inflows among all other push factors, labour cost, electricity price, real exchange rate and host CR indices have strong influential on FDI as the most effective pull factors. However, study fails to find any effect of openness, tax rates on commercial profits, USA CR indices, interest rate differentials and host real GDP growth on FDI.

  1. The 'push-pull' dosimeter: When two pigments are better than one

    Energy Technology Data Exchange (ETDEWEB)

    Bosi, Stephen G; Baldock, Clive; Smee, Robert, E-mail: s.bosi@physics.usyd.edu.a

    2010-11-01

    A new kind of gel dosimeter (the 'push-pull' dosimeter) is proposed which would contain two spectrally complementary pigments, one which darkens with increasing dose and another which bleaches. The bleaching pigment would be optimised for high sensitivity and the darkening pigment for low sensitivity. By employing dual pigments optimised independently, the usual requisite compromises between sensitivity at low dose and accuracy at high dose would be relaxed. Such a gel, after exposure would be read using two successive optical CT scans employing two different scan wavelengths. The use of dual pigments could also reduce the occurrence of regions of high optical attenuation which generate artefacts in optical CT. This paper also presents results of simulations of the behaviour of such a gel when scanned using optical cone beam CT.

  2. Theoretical study on charge injection and transport properties of six emitters with push-pull structure

    Science.gov (United States)

    Lin, Tao; Liu, Xiaojun; Lou, Zhidong; Hou, Yanbing; Teng, Feng

    2014-08-01

    The charge injection and transport properties of six organic light-emitting molecules with push-pull structures were studied by theoretical calculations. The ground-state geometries for the neutral, cationic and anionic states were optimized using density functional theory. Subsequently, the ionization potentials and electron affinities were calculated. We computed the reorganization energies and the transfer integrals based on the Marcus electron transfer theory. It was found that in addition to being emitters the six compounds are multifunctional materials being capable of transport for both holes and electrons. Moreover, the double-branched compound DCDPC2 was found to have higher charge injection ability and better balanced charge transport properties than single-branched compounds.

  3. Coumarin Push-Pull NLOphores with Red Emission: Solvatochromic and Theoretical Approach.

    Science.gov (United States)

    Lanke, Sandip K; Sekar, Nagaiyan

    2016-05-01

    A new class of red emitting extensively conjugated donor-π-acceptor type dyes bearing coumarin units are investigated for nonlinear optical properties. The photophysical behaviour and the relation between structure and properties of the coumarin "push-pull" derivatives were investigated based on solvatochromism and experimentally observed shifts in emission maxima. The electronic coupling for the electron transfer reaction for the coumarin dyes are calculated with the generalized Mulliken-Hush method. We evaluated non-linear optical (NLO) properties of coumarin dyes using both experimental solvent dependent shift method and computational method. All the investigated coumarin dyes are showing large value for first (β) and second hyperpolarizability (γ). Density functional theory [B3LYP/6-31G(d)] and time dependent density functional theory (TDDFT) computations have been employed to have more understanding of structural, molecular, electronic and photophysical parameters of the coumarin dyes.

  4. NLOphoric studies in thiazole containing symmetrical push-pull fluorophores - Combined experimental and DFT approach

    Science.gov (United States)

    Telore, Rahul D.; Satam, Manjaree A.; Sekar, Nagaiyan

    2015-10-01

    A series of donor-π-acceptor extended styryl chromophores having carbazole as electron donor with thiazole bridge and cyano group as the electron acceptors are investigated for nonlinear optical properties. The geometries of the extended styryls were optimized and electronic excitation properties were estimated using TD-DFT. The experimental solvatochromic shifts and density functional theory (DFT) computations are employed to understand the nonlinear optical properties of new generation push-pull fluorophores containing carbazole and thiazole cores. The solvatochromic polarizability values are calculated by two-level quantum mechanical model. Density Functional Theory is explored to determine the liner hyperpolarizability (α0), static first hyperpolarizability (β0) and second order hyperpolarizability (γ) for extended styryls. The calculation carried out by B3LYP method and 6-31G (d) basis set at ground state and excited state in different solvent polarity. The thiazole bridge in extended styryl enhances the nonlinear optical properties.

  5. Rational Design of Push-Pull Fluorene Dyes: Synthesis and Structure-Photophysics Relationship.

    Science.gov (United States)

    Shaya, Janah; Fontaine-Vive, Fabien; Michel, Benoît Y; Burger, Alain

    2016-07-18

    Our work surveyed experimental and theoretical investigations to construct highly emissive D-π-A (D=donor, A=acceptor) fluorenes. The synthetic routes were optimised to be concise and gram-scalable. The molecular design was first rationalised by varying the electron-withdrawing group from an aldehyde, ketotriazole or succinyl to methylenemalonitrile or benzothiadiazole. The electron-donating group was next varied from aliphatic or aromatic amines to saturated cyclic amines ranging from aziridine to azepane. Spectroscopic studies correlated with TD-DFT calculations provided the optimised structures. The selected push-pull dyes exhibited visible absorptions, significant brightness, important solvatofluorochromism, mega-Stokes shifts (>250 nm) and dramatic shifts in emission to the near-infrared. The current library includes the comprehensive characterization of 16 prospective dyes for fluorescence applications. Among them, several fluorene derivatives bearing different conjugation anchors were tested for coupling and demonstrated to preserve the photophysical responses once further bound.

  6. Three-photon absorption in a push-pull type chromophore containing tricyanofuran acceptor

    Institute of Scientific and Technical Information of China (English)

    Yan Ji; Ying Qian; Zhi Qiang Zhou; Wei Lu; Yi Ping Cui

    2012-01-01

    Three-photon absorption (3PA) of a push-pull chromophore,2-(3-cyano-(3-(4-(dimethylamino)styryl)-5,5-dimethylcyclohex-2-enylidene)methyl)-5,5-dimethylfuran-2-ylidene) malononitrile (CFM) including TCF group was measured by the nonlinear transmission method using a femto-second Ti:Sapphire oscillator-amplifier laser system.Its three-photon absorption cross-sections at 1300 nm were 36.8 × 10-79 cm6 s2 in the solution of DMF and 12.3 × 10-79 cm6 s2 in the solution of CH2Cl2,respectively.The large values were got by experiments in this paper,which is a new exploration for these kinds of materials.The molecule has the potential application foreground of 3PA areas and optical power limiting.

  7. Push-pull strategy in the regulation of postembryonic root development.

    Science.gov (United States)

    Choe, Goh; Lee, Ji-Young

    2017-02-01

    Unlike animals, plants continue to grow throughout their lives. The stem cell niche, protected in meristems of shoots and roots, enables this process. In the root, stem cells produce precursors for highly organized cell types via asymmetric cell divisions. These precursors, which are "transit-amplifying cells," actively divide for several rounds before entering into differentiation programs. In this review, we highlight positive feedback regulation between shoot- and root-ward signals during the postembryonic root growth, which is reminiscent of a "push-pull strategy" in business parlance. This property of molecular networks underlies the regulation of stem cells and their organizer, the "quiescent center," as well as of the signaling between stem cell niche, transit-amplifying cells, and beyond. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Voltage inverter with push-pull topology to inject energy into electrical systems with modulation SPWM

    Directory of Open Access Journals (Sweden)

    Emerson Charles M. Silva

    2013-09-01

    Full Text Available This paper presents a proposal for a voltage inverter topology based on push-pull converters, switched at high frequency to inject energy into the grid from a source of DC power. A system using two reverse voltage static converters provides the power grid; energy in the form of alternating current, that can work in conjunction with the provision of utility power. Aiming at the possible use of renewable energy sources, that can be stored in the form of voltage continuous, such as wind, solar, hydroelectric and others. The functioning of topology is presented, such as the power and control circuits, as well as sizing components, theoretical and practical results achieved with the assembly of a prototype 100W of power and switching in 40khz, which after filtering provides the frequency of 60Hz, which is compatible with the Brazilian electrical system.

  9. Monitoring molecular orientational order in NLO push-pull based polymeric films via photoacoustic measurements

    Science.gov (United States)

    Torres-Zúñiga, V.; Castañeda-Guzmán, R.; Morales-Saavedra, O. G.; Pérez-Martínez, A. L.; Ogawa, T.

    2011-12-01

    The pulsed-laser photoacoustic-technique (PLPA) was implemented to characterize molecular orientational order and anisotropy in push-pull poled polymeric films as function of temperature and laser polarization. Traditionally, photoacoustic signals are considered to be directly proportional to the linear optical absorption in amorphous media. In this work, however, it is shown that photoacoustic signals can also be highly sensitive to the material anisotropy when convenient polarization dependent photoacoustic analyses are performed. Thus, variation of the molecular orientation in organic films, comprising rod-like polar chromophores, can be unambiguously monitored via rms-analyses performed on the amplitude of the generated opto-acoustical PLPA-signals as function of the incident laser polarization. This result can be useful for the characterization of organic-based nonlinear optical (NLO) poled films and, in general, in studies of anisotropic materials. In fact, in this work we were able to accurately determine the molecular order parameter ( ϕ) of a NLO-active spin-coated polymeric film containing optically active push-pull chromophores. These molecules, previously oriented via an electrical-poling procedure, are capable to exhibit strong second harmonic generation (SHG) effects. The PLPA-measurements were systematically compared to the linear UV-vis optical absorbance spectra while heating the poled film sample in order to monitor the thermally induced molecular disorder, so that the order parameter may be photo-acoustically evaluated via the PLPA-signals generated from the poled to the unpoled film phase. These PLPA-experiments were performed taking into account the UV-vis reference spectra for calibration and comparison purposes in the evaluation of the order parameter. A significant advantage of the PLPA-technique over commonly used optical spectral methodologies is its convenient applicability in samples exhibiting poor or null optical transmission.

  10. Exploiting phytochemicals for developing a 'push-pull' crop protection strategy for cereal farmers in Africa.

    Science.gov (United States)

    Khan, Zeyaur R; Midega, Charles A O; Bruce, Toby J A; Hooper, Antony M; Pickett, John A

    2010-10-01

    Lepidopteran stemborers and parasitic weeds in the genus Striga are major constraints to efficient production of cereals, the most important staple food crops in Africa. Smallholder farmers are resource constrained and unable to afford expensive chemicals for crop protection. Development of a push-pull approach for integrated pest and weed management is reviewed here. Appropriate plants were discovered that naturally emit signalling chemicals (semiochemicals). Plants highly attractive for egg laying by stemborer pests were selected and employed as trap crops (pull), to draw pests away from the main crop. Of these, Napier grass, Pennisetum purpureum (Schumach), despite its attractiveness, supported minimal survival of the pests' immature stages. Plants that repelled stemborer pests, notably molasses grass, Melinis minutiflora P. Beauv., and forage legumes in the genus Desmodium, were selected as intercrops (push). Desmodium intercrops suppress Striga hermonthica (Del.) Benth. through an allelopathic mechanism. Their root exudates contain novel flavonoid compounds, which stimulate suicidal germination of S. hermonthica seeds and dramatically inhibit its attachment to host roots. The companion crops provide valuable forage for farm animals while the leguminous intercrops also improve soil fertility and moisture retention. The system is appropriate as it is based on locally available plants, not expensive external inputs, and fits well with traditional mixed cropping systems in Africa. To date it has been adopted by more than 30,000 smallholder farmers in East Africa where maize yields have increased from ∼1 t ha(-1) to 3.5 t ha(-1). Future directions for semiochemical delivery by plants including biotechnological opportunities are discussed.

  11. The influence of push-pull states on the ultrafast intersystem crossing in nitroaromatics.

    Science.gov (United States)

    López-Arteaga, Rafael; Stephansen, Anne B; Guarin, Cesar A; Sølling, Theis I; Peon, Jorge

    2013-08-29

    The photochemistry of nitro-substituted polyaromatic compounds is generally determined by the rapid decay of its S1 state and the rapid population of its triplet manifold. Previous studies have shown that such an efficient channel is due to a strong coupling of the fluorescent state with specific upper receiver states in the triplet manifold. Here we examine variations in this mechanism through the comparison of the photophysics of 2-nitrofluorene with that of 2-diethylamino-7-nitrofluorene. The only difference between these two molecules is the presence of a diethylamino group in a push-pull configuration for the latter compound. The femtosecond-resolved experiments presented herein indicate that 2-nitrofluorene shows ultrafast intersystem crossing which depopulates the S1 emissive state within less than a picosecond. On the other hand, the amino substituted nitrofluorene shows a marked shift in its S1 energy redounding in the loss of coupling with the receiver triplet state, and therefore a much longer lifetime of 100 ps in cyclohexane. In polar solvents, the diethylamino substituted compound actually shows double peaked fluorescence due to the formation of charge transfer states. Evaluation of the Stokes shifts in different solvents indicates that both bands correspond to intramolecular charge transfer states in equilibrium which are formed in an ultrafast time scale from the original locally excited (LE) state. The present study addresses the interplay between electron-donating and nitro substituents, showing that the addition of the electron-donating amino group is able to change the coupling with the triplet states due to a stabilization of the first excited singlet state and the rapid formation of charge transfer states in polar solvents. We include calculations at the TD-DFT level of theory with the PBE0 and B3LYP functionals which nicely predict the observed difference between the two compounds, showing how the specific S(π-π*)-T(n-π*) coupling normally

  12. Electron correlation effects on the first hyperpolarizability of push-pull π-conjugated systems.

    Science.gov (United States)

    de Wergifosse, Marc; Champagne, Benoît

    2011-02-21

    The first hyperpolarizability (β) of representative push-pull π-conjugated compounds has been calculated at several levels of approximation to assess the effects of electron correlation. First, the 6-31+G(d) basis set has been shown to give the best balance between accuracy and computational resources for a polyene linker whereas for polyyne linker, the 6-31G(d) basis set is already an optimal choice. As a result of cancellations between higher order contributions, the MP2 method turns out to be the method of choice to predict β of push-pull π-conjugated systems since it closely reproduces the values obtained with the reference CCSD(T) scheme. Moreover, the SDQ-MP4 and CCSD approaches provide rarely improved estimates over MP2 while the MP4 method does not represent an improvement over MP4-SDQ or the SCS-MP2 method, over MP2. Among density functional theory exchange-correlation functionals, LC-BLYP is reliable when characterizing the changes of first hyperpolarizability upon enlarging the π-conjugated linker or upon changing the polyyne linker into a polyene segment. Nevertheless, its reliability is very similar to what can be achieved with the Hartree-Fock method and the MP2 scheme is by far more accurate. On the other hand, the BLYP, B3LYP, and BHandHLYP functionals perform quantitatively better in a number of cases but the trends are poorly described. This is also the case of the B2-PLYP and mPW2-PLYP functionals, which are often the most accurate, though they underestimate the increase of β when going from polyyne to polyene linkers and overestimate the enhancement of β with chain length.

  13. Pulled in or pushed out? Understanding the complexities of motivation for alternative therapies use in Ghana

    Directory of Open Access Journals (Sweden)

    Razak Mohammed Gyasi

    2016-03-01

    Full Text Available The impact of strong cultural beliefs on specific reasons for traditional medicine (TRM use among individuals and populations has long been advanced in health care and spatio-medical literature. Yet, little has been done in Ghana and the Ashanti Region in particular to bring out the precise “pull” and “push” relative influences on TRM utilization. With a qualitative research approach involving rural and urban character, the study explored health beliefs and motivations for TRM use in Kumasi Metropolis and Sekyere South District, Ghana. The study draws on data from 36 in-depth interviews with adults, selected through theoretical sampling. We used the a posteriori inductive reduction model to derive broad themes and subthemes. The “pull factors”—perceived benefits in TRM use vis-à-vis the “push factors”—perceived poor services of the biomedical treatments contributed to the growing trends in TRM use. The result however indicates that the “pull factors,” viz.—personal health beliefs, desire to take control of one's health, perceived efficacy, and safety of various modalities of TRM—were stronger in shaping TRM use. Poor access to conventional medicine accounted for the differences in TRM use between rural and urban areas. Understanding the treatment and health-seeking behaviour of a cultural-related group is critical for developing and sustaining traditional therapy in Ghana.

  14. Generic, Extensible, Configurable Push-Pull Framework for Large-Scale Science Missions

    Science.gov (United States)

    Foster, Brian M.; Chang, Albert Y.; Freeborn, Dana J.; Crichton, Daniel J.; Woollard, David M.; Mattmann, Chris A.

    2011-01-01

    The push-pull framework was developed in hopes that an infrastructure would be created that could literally connect to any given remote site, and (given a set of restrictions) download files from that remote site based on those restrictions. The Cataloging and Archiving Service (CAS) has recently been re-architected and re-factored in its canonical services, including file management, workflow management, and resource management. Additionally, a generic CAS Crawling Framework was built based on motivation from Apache s open-source search engine project called Nutch. Nutch is an Apache effort to provide search engine services (akin to Google), including crawling, parsing, content analysis, and indexing. It has produced several stable software releases, and is currently used in production services at companies such as Yahoo, and at NASA's Planetary Data System. The CAS Crawling Framework supports many of the Nutch Crawler's generic services, including metadata extraction, crawling, and ingestion. However, one service that was not ported over from Nutch is a generic protocol layer service that allows the Nutch crawler to obtain content using protocol plug-ins that download content using implementations of remote protocols, such as HTTP, FTP, WinNT file system, HTTPS, etc. Such a generic protocol layer would greatly aid in the CAS Crawling Framework, as the layer would allow the framework to generically obtain content (i.e., data products) from remote sites using protocols such as FTP and others. Augmented with this capability, the Orbiting Carbon Observatory (OCO) and NPP (NPOESS Preparatory Project) Sounder PEATE (Product Evaluation and Analysis Tools Elements) would be provided with an infrastructure to support generic FTP-based pull access to remote data products, obviating the need for any specialized software outside of the context of their existing process control systems. This extensible configurable framework was created in Java, and allows the use of

  15. Why People Choose to Teach in Urban Schools: The Case for a Push-Pull Factor Analysis

    Science.gov (United States)

    Knell, Paul F.; Castro, Antonio J.

    2014-01-01

    This qualitative research study traces the motivations for teaching of 13 teacher candidates enrolled in an urban-based alternative certification program. After using a push-pull factor analysis, the data suggest that most participants left their previous careers due to financial shortcomings or work instability. As a result, these participants…

  16. Evaluation of Interhandle Distance During Pushing and Pulling of a Four-Caster Cart for Upper Limb Exertion

    Directory of Open Access Journals (Sweden)

    Akihiro Ohnishi

    2016-09-01

    Conclusion: A wider interhandle distance, such as 80 cm, was not suitable in the forwardbackward movement of the RBP. Therefore, this study concluded that an interhandle distance of 40 cm would be suitable for pushing and pulling an RBP to protect the workers' hands against the risk of injury by installing inner handles.

  17. Novel family of quasi-Z-source DC/DC converters derived from current-fed push-pull converters

    DEFF Research Database (Denmark)

    Chub, Andrii; Husev, Oleksandr; Vinnikov, Dmitri

    2014-01-01

    This paper is devoted to the step-up quasi-Z-source dc/dc push-pull converter family. The topologies in the family are derived from the isolated boost converter family by replacing input inductors with the quasi-Z-source network. Two new topologies are proposed, analyzed and compared. Theoretical...

  18. Integration of repellents, attractants, and insecticides in a "push-pull" strategy for managing German cockroach (Dictyoptera: Blattellidae) populations.

    Science.gov (United States)

    Nalyanya, G; Moore, C B; Schal, C

    2000-05-01

    "Push-pull" is a behavior manipulation strategy in which behavior-modifying stimuli are integrated with a pest control agent. We evaluated the efficacy of an insecticide bait in combination with attractants ("pull"), repellents ("push"), or both ("push-pull") using a hydramethylnon-based bait, feces-contaminated surfaces as an attractant, and methyl neodecanamide-treated surfaces to repel cockroaches. Both adult males and first-instar German cockroaches, Blattella germanica (L.), chose shelters nearest the attractant-treated surfaces and farthest from the repellent-treated surfaces. Food consumption was highest from food nearest the preferred shelters, and mortality was highest when the insecticide bait was near the preferred shelter. These patterns were more apparent in first instars than in adults. Our results from large arena studies in the laboratory show that the push-pull strategy can be used to displace pests from resources or commodities that are to be protected, and simultaneously lure the pest to an attractant source coupled with a pest control agent. Concentrating cockroaches into a limited area should facilitate the precision-targeting of the pest population and promises to reduce insecticide use.

  19. Research on Flow Field Characteristics Affected by Obstacles of Pull-Push Ventilation System of Plating Tanks through Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Hu Hong

    2016-01-01

    Full Text Available Pull-push ventilation system, with high capture efficiency, is universally used to capture contaminants from containment generation where can’t be enclosed and where the working area is large. When there are obstacles between the pull hood and the push hood, the air jet will disperse, leaving contaminants out of control, causing atmosphere polluted. This paper aims to discuss flow filed of pull-push ventilation system, located in some tank of some plating workshop, with obstacles between pull hood and push hood. Mathematical model, involving physical model, assumptions, governing equations, boundary conditions and grid separation is established. By CFD code FLUENT, flow field, containing velocity field and concentration field, is achieved. To verify the simulation models, velocity field for simulation results is compared with the theory results, while concentration field for simulation results with experimental results. The comparison results show that the results matches well and that mathematical model proposed in this paper is reasonable, helpful and realistic significant in designing this kind exhaust ventilation systems where obstacles presence.

  20. A Push-Pull CORF Model of a Simple Cell with Antiphase Inhibition Improves SNR and Contour Detection

    NARCIS (Netherlands)

    Azzopardi, George; Rodriguez-Sanchez, Antonio; Piater, Justus; Petkov, Nicolai

    2014-01-01

    We propose a computational model of a simple cell with push-pull inhibition, a property that is observed in many real simple cells. It is based on an existing model called Combination of Receptive Fields or CORF for brevity. A CORF model uses as afferent inputs the responses of model LGN cells with

  1. Do PhDs Voluntarily Opt for Private Sector Employment? Evidence of Push and Pull Effects on Mobility Choices

    DEFF Research Database (Denmark)

    Pedersen, Heidi Skovgaard

    2014-01-01

    In Denmark, policy makers have increased admissions to PhD programs to ensure the flow of researchers into the private sector, thereby increasing knowledge transfer. However, we know little about the factors influencing the sector mobility of PhD graduates. While opting for employment...... in the private sector might be driven by personal preferences, there might also be external factors pushing PhDs to choose the private sector. This article examines the push and pull effects on mobility choices using duration models to estimate the transition rates to private sector employment. The analyses show...... that the preference for and ability to do academic science reduces transition rates to the private sector, whereas being in a research position and earnings potential are attractors to the private sector. Hence, both push and pull effects determine sector mobility. Once the initial sector choice has been made...

  2. Characterization of Anomalous Contaminant Transport via Push-Pull Tracer Tests

    Science.gov (United States)

    Hansen, S. K.; Vesselinov, V. V.; Berkowitz, B.

    2015-12-01

    Push-pull (single-well-injection-withdrawal) tracer tests are widely used as an economical means of characterizing field-scale solute transport properties such as sorption and dispersion. Typically, these are analyzed by means of analytic solutions that assume transport obeys the radial advection-dispersion equation. We revisit this approach as: (1) Recognition of the ubiquity of anomalous transport and its impact on contaminant remediation necessitates the use of new methods to characterize it, and (2) Improved computational power and numerical methods have rendered reliance on analytical solutions obsolete. Here, we present a technique for characterizing diffusion-driven anomalous transport (i.e., anomalous transport driven by a "trapping" process whose trapping and release statistics are independent of the groundwater flow velocity). Examples include diffusion into low permeability zones, kinetic sorption, and matrix diffusion. Using field observations, we simultaneously calibrate an exponential probability distribution for time spent on a single sojourn in the mobile domain and a truncated power law probability distribution for time spent on a single sojourn in the immobile domain via a stochastic global optimization technique. The calibrated distributions, being independent of the flow regime, are applicable to the same domain under any flow conditions, including linear flow. In the context of the continuous time random walk (CTRW), one may simply define a transition to represent a single trap-and-release cycle, and directly compute the spatiotemporal transition distribution that defines the CTRW from the two calibrated distributions and the local seepage velocity (so that existing CTRW transport theory applies). A test of our methodology against a push-pull test from the MADE site demonstrated fitting performance comparable to that of a 3-D MODFLOW/MT3DMS model with a variety of hydraulic conductivity zones and explicit treatment of mobile-immobile mass

  3. Design and Modeling of a Square Planar Inductor for a Push Pull Converter

    Directory of Open Access Journals (Sweden)

    GUETTAF Yacine

    2015-05-01

    Full Text Available The scope of this work is the modeling and the simulation of a square planar spiral inductor; in order to integrate it into a selected electronic power converter. At first, from the operating conditions of an isolated DC-DC converter, we estimate the required values for the dimensioning of the inductance of the output of this device, which means; the determination of its various physical and geometrical parameters. Modeling requires the identification and consideration of various parasitic elements and their effects on the equivalent physical model of the inductor. The parametric study we conducted by MATLAB focused primarily on calculating the quality factor of the inductor then the influence of geometrical parameters on both the electrical, physical and frequency behavior of the square planar spiral inductor and the quality factor of the inductor. Finally, a comparative study by the PSIM software between a conventional inductor used in a DC-DC converter: push-pull, and an integrated inductor in the same selected structure gave desired results.

  4. A comparison of push and pull production controls under machine breakdown

    Directory of Open Access Journals (Sweden)

    Prakash, J.

    2011-01-01

    Full Text Available Production control for high-mix production remains a complex issue. Common pull system replenishment generates large works-in-process (WIPs for each part type, especially under breakdown. This paper attempts to solve this by presenting a production control that classifies parts into two categories. The performances of three production control mechanisms under breakdown are compared. The production control mechanisms in consideration are push, shared constant WIP (CONWIP, and parallel CONWIP. A full-factorial simulation experiment was conducted. ANOVA was performed to determine the significant effects of input factors. Response surface methodology was used to demonstrate the behavior of performance measures in terms of these significant input factors. The results prove that parallel CONWIP is superior over shared CONWIP in terms of the average flow time per part. If categorical dispatch rules are employed, parallel CONWIP outperforms shared CONWIP in terms of service level. With high card count, parallel CONWIP generally produces lower bottleneck utilizations while maintaining a low average flow time per part than shared CONWIP.

  5. Modeling the impact of granular embedding media, and pulling versus pushing cells on growing cell clones

    Science.gov (United States)

    Drasdo, Dirk; Hoehme, Stefan

    2012-05-01

    In this paper, we explore how potential biomechanical influences on cell cycle entrance and cell migration affect the growth dynamics of cell populations. We consider cell populations growing in free, granular and tissue-like environments using a mathematical single-cell-based model. In a free environment we study the effect of pushing movements triggered by proliferation versus active pulling movements of cells stretching cell-cell contacts on the multi-cellular kinetics and the cell population morphotype. By growing cell clones embedded in agarose gel or cells of another type, one can mimic aspects of embedding tissues. We perform simulation studies of cell clones expanding in an environment of granular objects and of chemically inert cells. In certain parameter ranges, we find the formation of invasive fingers reminiscent of viscous fingering. Since the simulation studies are highly computation-time consuming, we mainly study one-cell-thick monolayers and show that for selected parameter settings the results also hold for multi-cellular spheroids. Finally, we compare our model to the experimentally observed growth dynamics of multi-cellular spheroids in agarose gel.

  6. Synthesis of Naphthalene-Based Push-Pull Molecules with a Heteroaromatic Electron Acceptor.

    Science.gov (United States)

    Šarlah, David; Juranovič, Amadej; Kožar, Boris; Rejc, Luka; Golobič, Amalija; Petrič, Andrej

    2016-03-02

    Naphthalene derivatives bearing electron-accepting and electron-donating groups at the 2,6-positions belong to the family of D-π-A push-pull dyes. It has been found that these compounds, e.g., 2-(1-(6-((2-(fluoro)ethyl)(methyl)amino)naphthalen-2-yl)ethylidene)malononitrile (FDDNP), show not only interesting optical properties, such as solvatochromism, but they have the potential to label protein aggregates of different compositions formed in the brain of patients suffering from neurodegenerative diseases like Alzheimer's (AD). In continuation of our research we set our goal to find new FDDNP analogs, which would inherit optical and binding properties but hopefully show better specificity for tau protein aggregates, which are characteristic for neurodegeneration caused by repetitive mild trauma. In this work we report on the synthesis of new FDDNP analogs in which the acceptor group has been formally replaced with an aromatic five- or six-membered heterocycle. The heterocyclic moiety was annealed to the central naphthalene ring either by classical ring closure reactions or by modern transition metal-catalyzed coupling reactions. The chemical characterization, NMR spectra, and UV/vis properties of all new compounds are reported.

  7. Push-pull with recovery stage high-voltage DC converter for PV solar generator

    Science.gov (United States)

    Nguyen, The Vinh; Aillerie, Michel; Petit, Pierre; Pham, Hong Thang; Vo, Thành Vinh

    2017-02-01

    A lot of systems are basically developed on DC-DC or DC-AC converters including electronic switches such as MOS or bipolar transistors. The limits of efficiency are quickly reached when high output voltages and high input currents are needed. This work presents a new high-efficiency-high-step-up based on push-pull DC-DC converter integrating recovery stages dedicated to smart HVDC distributed architecture in PV solar energy production systems. Appropriate duty cycle ratio assumes that the recovery stage work with parallel charge and discharge to achieve high step-up voltage gain. Besides, the voltage stress on the main switch is reduced with a passive clamp circuit and thus, low on-state resistance Rdson of the main switch can be adopted to reduce conduction losses. Thus, the efficiency of a basic DC-HVDC converter dedicated to renewable energy production can be further improved with such topology. A prototype converter is developed, and experimentally tested for validation.

  8. Intramolecular Charge Transfer and Solvation of Photoactive Molecules with Conjugated Push-Pull Structures.

    Science.gov (United States)

    Zhu, Huaning; Wang, Xian; Ma, Renjun; Kuang, Zhuoran; Guo, Qianjin; Xia, Andong

    2016-10-18

    A comparative investigation on the photophysical properties and solvation-related ICT dynamics of three push-pull compounds containing different donors including carbazole, triphenylamine and phenothiazine, was performed. The steady-state spectra and theoretical calculations show the charge transfers from the central donors to the acceptors at each side. The characterization of the extent of charge transfer was determined by various means, including estimation of the dipole moment, the electron density distribution of HOMO and LUMO, CDD and change in Gibb's free energy, which show the charge transfer strength to be in the order PDHP > BDHT > PDHC. This suggests that the electron-donating ability of the donor groups plays a crucial role in the charge transfer in these compounds. The TA data show the excited-state relaxation dynamics follow a sequential model: FC→ICT→ICT'→S0 , and are affected by the solvent polarity. The results presented here demonstrate that the compound with a higher degree of ICT characteristic interacts more strongly with stronger polar solvent molecules, which can accelerate the solvation and spectral evolution to lower energy levels. The A-π-D-π-A architectures with prominent ICT characteristics based on carbazole, triphenylamine and phenothiazine might be potential scaffolds for light-harvesting and photovoltaic devices. These results are of value for understanding structure-property relationships and the rational design of functional materials for photoelectric applications.

  9. Equivalent magnetic noise in multi- push-pull configuration magnetoelectric composites: model and experiment.

    Science.gov (United States)

    Wang, Yaojin; Hasanyan, Davresh; Li, Menghui; Gao, Junqi; Li, Jiefang; Viehland, Dwight

    2013-06-01

    A theoretical model for the multi-push-pull configuration of magnetoelectric (ME) laminated composites comprising magnetostrictive and piezoelectric layers with interdigitated electrodes encapsulated in polyimide film is presented. Analytical solutions for the ME voltage coefficient αE, ME charge coefficient αQ, noise charge density and equivalent magnetic noise were derived. Parametric studies are presented to evaluate the influence of material properties and polyimide film geometries. The results show that the value of αE was determined by the parameters of the magnetostrictive and piezoelectric phases, and that the values of αQ and noise charge density were determined not only by the component parameters, but also by the volume fraction of the piezoelectric phase and polyimide film geometry. The equivalent magnetic noise had no dependence on the polyimide film geometry, but rather was determined by the component parameters and the volume fraction of the piezoelectric phase. Theoretical and experimental results are compared and shown to have good agreement with each other.

  10. Hydrogen-bond basicity of push-pull α,β-unsaturated enaminoketones

    Science.gov (United States)

    Vdovenko, Sergey I.; Gerus, Igor I.; Fedorenko, Elena A.; Kukhar, Valery P.

    2010-08-01

    A method is proposed for evaluating the hydrogen-bond basicity of certain conformers of two push-pull enaminoketones with the general formula R sbnd C(O) sbnd CH dbnd CH sbnd N(CH 3) 2, where R=CH 3 (DMBN); R=CF 3 (DMTBN). It has been shown, for both enaminoketones, that the ( EE) conformer has a higher basicity than the ( EZ) conformer. Moreover, the (DMBN) has one of the highest general p KHB values in the hydrogen-bond basicity scale of ketones. Substitution of the CH 3-group in (DMBN) with the CF 3-group in (DMTBN) reduces general p KHB sharply as a consequence of electron withdrawal of CF 3-group. Hydrogen bond sites are also discussed; it is shown that, in both enaminoketones, carbonyl oxygen possesses the maximal basicity, whereas nitrogen of the dimethylamino group has less basicity, and the vinyl moiety is the least basic site. Enthalpies of hydrogen bond formation (-Δ H) in absolute values, as well as the respective p KHB values, are greater for the ( EE) conformer than for the ( EZ) as a consequence of greater contribution of resonance structure in the ( EE) form. ?

  11. Simulation of nZVI Transport at a Push-Pull Field Trial

    Science.gov (United States)

    O'Carroll, D. M.; Oleniuk, A. J.; Kocur, C. M.; Sleep, B. E.; Xiong, Z.; Bennett, P.

    2010-12-01

    Nano-scale Zero Valent Iron (nZVI) is receiving significant attention due to its ability to rapidly reduce priority source zone contaminants (eg: chlorinated compounds) in controlled laboratory experiments. Although nZVI has shown significant promise in laboratory experiments the limited field studies completed to date have found that nZVI subsurface mobility is less than expected. For example, nZVI is stable in aqueous solutions for extended periods of time (eg: days) and stabilized nZVI is quite mobile in laboratory column experiments. However, field scale studies have found mobility decreases significantly in one day. To explore the causes for lower than expected mobility at the field scale a two-dimensional numerical model (Compsim) was developed to simulate the movement of nZVI observed at an actual field pilot study. Simulation results were in very good agreement with the three conservative tracer and nZVI push-pull field trials. Results suggest that subsurface heterogeneities and the viscous nature of the polymers used to stabilize nZVI decrease pore water velocity thereby limiting nZVI transport. Furthermore, nZVI aggregation in the injection vessel decreased the amount of nZVI delivered to the subsurface below what was expected. Results from this study will be used to optimize nZVI injection strategies.

  12. The Effects of Direction of Exertion, Path, and Load Placement in Nursing Cart Pushing and Pulling Tasks: An Electromyographical Study.

    Science.gov (United States)

    Kao, Huei Chu; Lin, Chiuhsiang Joe; Lee, Yung Hui; Chen, Su Huang

    2015-01-01

    The purpose of this study was to explore the effects of direction of exertion (DOE) (pushing, pulling), path (walking in a straight line, turning left, walking uphill), and load placement (LP) (the 18 blocks were indicated by X, Y and Z axis; there were 3 levels on the X axis, 2 levels on the Y axis, and 3 levels on the Z axis) on muscle activity and ratings of perceived exertion in nursing cart pushing and pulling tasks. Ten participants who were female students and not experienced nurses were recruited to participate in the experiment. Each participant performed 108 experimental trials in the study, consisting of 2 directions of exertion (push and pull), 3 paths, and 18 load placements (indicated by X, Y and Z axes). A 23kg load was placed into one load placement. The dependent variables were electromyographic (EMG) data of four muscles collected bilaterally as follows: Left (L) and right (R) trapezius (TR), flexor digitorum superficialis (FDS), extensor digitorum (ED), and erector spinae (ES) and subjective ratings of perceived exertion (RPE). Split-split-plot ANOVA was conducted to analyze significant differences between DOE, path, and LP in the EMG and RPE data. Pulling cart tasks produced a significantly higher activation of the muscles (RTR:54.4%, LTR:50.3%, LFDS:57.0%, LED:63.4%, RES:40.7%, LES:36.7%) than pushing cart tasks (RTR:42.4%, LTR:35.1%, LFDS:32.3%, LED:55.1%, RES:33.3%, LES:32.1%). A significantly greater perceived exertion was found in pulling cart tasks than pushing cart tasks. Significantly higher activation of all muscles and perceived exertion were observed for walking uphill than walking in a straight line and turning left. Significantly lower muscle activity of all muscles and subject ratings were observed for the central position on the X axis, the bottom position on the Y axis, and the posterior position on the Z axis. These findings suggest that nursing staff should adopt forward pushing when moving a nursing cart, instead of backward

  13. The Effects of Direction of Exertion, Path, and Load Placement in Nursing Cart Pushing and Pulling Tasks: An Electromyographical Study.

    Directory of Open Access Journals (Sweden)

    Huei Chu Kao

    Full Text Available The purpose of this study was to explore the effects of direction of exertion (DOE (pushing, pulling, path (walking in a straight line, turning left, walking uphill, and load placement (LP (the 18 blocks were indicated by X, Y and Z axis; there were 3 levels on the X axis, 2 levels on the Y axis, and 3 levels on the Z axis on muscle activity and ratings of perceived exertion in nursing cart pushing and pulling tasks. Ten participants who were female students and not experienced nurses were recruited to participate in the experiment. Each participant performed 108 experimental trials in the study, consisting of 2 directions of exertion (push and pull, 3 paths, and 18 load placements (indicated by X, Y and Z axes. A 23kg load was placed into one load placement. The dependent variables were electromyographic (EMG data of four muscles collected bilaterally as follows: Left (L and right (R trapezius (TR, flexor digitorum superficialis (FDS, extensor digitorum (ED, and erector spinae (ES and subjective ratings of perceived exertion (RPE. Split-split-plot ANOVA was conducted to analyze significant differences between DOE, path, and LP in the EMG and RPE data. Pulling cart tasks produced a significantly higher activation of the muscles (RTR:54.4%, LTR:50.3%, LFDS:57.0%, LED:63.4%, RES:40.7%, LES:36.7% than pushing cart tasks (RTR:42.4%, LTR:35.1%, LFDS:32.3%, LED:55.1%, RES:33.3%, LES:32.1%. A significantly greater perceived exertion was found in pulling cart tasks than pushing cart tasks. Significantly higher activation of all muscles and perceived exertion were observed for walking uphill than walking in a straight line and turning left. Significantly lower muscle activity of all muscles and subject ratings were observed for the central position on the X axis, the bottom position on the Y axis, and the posterior position on the Z axis. These findings suggest that nursing staff should adopt forward pushing when moving a nursing cart, instead of

  14. The field evaluation of a push-pull system to control malaria vectors in northern Belize, Central America.

    Science.gov (United States)

    Wagman, Joseph M; Grieco, John P; Bautista, Kim; Polanco, Jorge; Briceño, Ireneo; King, Russell; Achee, Nicole L

    2015-04-29

    Campaigns for the continued reduction and eventual elimination of malaria may benefit from new and innovative vector control tools. One novel approach being considered uses a push-pull strategy, whereby spatial repellents are used in combination with outdoor baited traps. The desired effect is the behavioural manipulation of mosquito populations to elicit movement of vectors away from people and into traps. Here, a prototype push-pull intervention was evaluated using an experimental hut methodology to test proof-of-principle for the strategy against two natural vector populations, Anopheles albimanus and Anopheles vestitipennis, in Belize, Central America. A Latin square study design was used to compare mosquito entry into experimental huts and outdoor traps across four different experimental conditions: 1) control, with no interventions; 2) pull, utilizing only outdoor traps; 3) push, utilizing only an indoor spatial repellent; and 4) push-pull, utilizing both interventions simultaneously. For An. vestitipennis, the combined use of an indoor repellent and outdoor baited traps reduced average nightly mosquito hut entry by 39% (95% CI: [0.37-0.41]) as compared to control and simultaneously increased the nightly average densities of An. vestitipennis captured in outdoor baited traps by 48% (95% CI: [0.22-0.74]), compared to when no repellent was used. Against An. albimanus, the combined push-pull treatment similarly reduced hut entry, by 54% (95% CI: [0.40-0.68]) as compared to control; however, the presence of a repellent indoors did not affect overall outdoor trap catch densities for this species. Against both anopheline species, the combined intervention did not further reduce mosquito hut entry compared to the use of repellent alone. The prototype intervention evaluated here clearly demonstrated that push-pull strategies have potential to reduce human-vector interactions inside homes by reducing mosquito entry, and highlighted the possibility for the strategy to

  15. Electronic state of push-pull alkenes: an experimental dynamic NMR and theoretical ab initio MO study.

    Science.gov (United States)

    Kleinpeter, Erich; Klod, Sabrina; Rudorf, Wolf-Dieter

    2004-06-25

    The (1)H and (13)C NMR spectra of a number of push-pull alkenes were recorded and the (13)C chemical shifts calculated employing the GIAO perturbation method. Of the various levels of theory tried, MP2 calculations with a triple-zeta-valence basis set were found to be the most effective for providing reliable results. The effect of the solvent was also considered but only by single-point calculations. Generally, the agreement between the experimental and theoretically calculated (13)C chemical shifts was good with only the carbons of the carbonyl, thiocarbonyl, and cyano groups deviating significantly. The substituents on the different sides of the central C=C partial double bond were classified qualitatively with respect to their donor (S,S theory and the free energy differences compared with the barriers to rotation determined experimentally by dynamic NMR spectroscopy. Structural differences between the various push-pull alkenes were reproduced well, but the barriers to rotation were generally overestimated theoretically. Nevertheless, by correlating the barriers to rotation and the length of the central C=C partial double bonds, the push-pull alkenes could be classified with respect to the amount of hydrogen bonding present, the extent of donor-acceptor interactions (the push-pull effect), and the level of steric hindrance within the molecules. Finally, by means of NBO analysis of a set of model push-pull alkenes (acceptors: -C identical with N, -CH=O, and -CH=S; donors: S, O, and NH), the occupation numbers of the bonding pi orbitals of the central C=C partial double bond were shown to quantitatively describe the acceptor powers of the substituents and the corresponding occupation numbers of the antibonding pi orbital the donor powers of the substituents. Thus, for the first time an estimation of both the acceptor and the donor properties of the substituents attached to the push-pull double bond have been separately quantified. Furthermore, both the balance

  16. 基于DTN网络的PUSH-PULL策略研究%DTN-based Network, PUSH-PULL Strategy

    Institute of Scientific and Technical Information of China (English)

    崔永锋

    2010-01-01

    DTN网络是新一代的网络体系结构,PUSH-PULL是解决DTN网络中拥塞控制的一种有效策略,介绍了DTN网络中拥塞控制的研究现状,并对PUSH-PULL的各个策略进行了阐述,通过NS2搭建DTN网络环境并通过模拟对PUSH-PULL的7种策略进行仿真,模拟仿真结果表明,采用PUSH-PULL策略的可以有效的提高信息的传输率.

  17. Challenges And Concepts for Design of An Interaction Region With Push-Pull Arrangement of Detectors - An Interface Document

    Energy Technology Data Exchange (ETDEWEB)

    Parker, B.; /Brookhaven; Herve, Alain; Osborne, J.; /CERN; Mikhailichenko, A.; /Cornell U., Phys. Dept.; Buesser, K.; /DESY; Ashmanskas, B.; Kuchler, Victor P.; Mokhov, N.; /Fermilab; Enomoto, A.; Sugimoto, Y.; Tauchi, T.; Tsuchiya, K.; /KEK, Tsukuba; Weisend, J.; /NSF, Wash., D.C.; Burrows, P.; /Oxford U.; Markiewicz, Thomas W.; Oriunno, M.; Seryi, Andrei; Sullivan, M.; /SLAC; Angal-Kalinin, D.; /Rutherford; Sanuki, T.; Yamamoto, H.; /Tohoku U.

    2011-10-14

    Two experimental detectors working in a push-pull mode has been considered for the Interaction Region of the International Linear Collider. The push-pull mode of operation sets specific requirements and challenges for many systems of detector and machine, in particular for the IR magnets, for the cryogenics and alignment system, for beamline shielding, for detector design and overall integration, and so on. These challenges and the identified conceptual solutions discussed in the paper intend to form a draft of the Interface Document which will be developed further in the nearest future. The authors of the present paper include the organizers and conveners of working groups of the workshop on engineering design of interaction region IRENG07, the leaders of the IR Integration within Global Design Effort Beam Delivery System, and the representatives from each detector concept submitting the Letters Of Intent.

  18. A first principles DFT study of UV-visible absorbing low band gap push-pull polymer

    Science.gov (United States)

    Jain, Kalpna; Kishor, Shyam; Singh, Kh. S.; Ramaniah, Lavanya M.

    2016-05-01

    Low band gap (below 2 eV) semiconducting π-conjugated polymers made up of alternate donor and acceptor moieties having push-pull feature are promising materials for organic solar cells due to strong absorption of the solar spectrum. In this work, the band gap of a polysilole based push-pull polymer has been estimated by the application of periodic boundary condition (PBC) using density functional theory (DFT) with B3LYP functional and the 6-311G(d,p) basis set. The estimated band gap is found to be below 2 eV. The absorption spectra of the polymer obtained using time-dependent DFT (TDDFT) covers a wide range of wavelength.

  19. Integration of market pull and technology push in the corporate front end and innovation management - Insights from the German software industry

    DEFF Research Database (Denmark)

    Brem, Alexander; Voigt, K.-I.

    2009-01-01

    will be introduced as to how market pull and technology push activities within the corporate technology and innovation management can be integrated. Hence, the purpose of the paper is to introduce a theory-based conceptual framework that can be used in today’s corporate environment. In this context, technology......Within the framework of this paper, an extensive literature overview of technology and innovation management aspects on market pull and technology push will be given. The existing classification of market pull and technology push will be particularly shown and called into question by suggesting...

  20. Design of a haptic device with grasp and push-pull force feedback for a master-slave surgical robot.

    Science.gov (United States)

    Hu, Zhenkai; Yoon, Chae-Hyun; Park, Samuel Byeongjun; Jo, Yung-Ho

    2016-07-01

    We propose a portable haptic device providing grasp (kinesthetic) and push-pull (cutaneous) sensations for optical-motion-capture master interfaces. Although optical-motion-capture master interfaces for surgical robot systems can overcome the stiffness, friction, and coupling problems of mechanical master interfaces, it is difficult to add haptic feedback to an optical-motion-capture master interface without constraining the free motion of the operator's hands. Therefore, we utilized a Bowden cable-driven mechanism to provide the grasp and push-pull sensation while retaining the free hand motion of the optical-motion capture master interface. To evaluate the haptic device, we construct a 2-DOF force sensing/force feedback system. We compare the sensed force and the reproduced force of the haptic device. Finally, a needle insertion test was done to evaluate the performance of the haptic interface in the master-slave system. The results demonstrate that both the grasp force feedback and the push-pull force feedback provided by the haptic interface closely matched with the sensed forces of the slave robot. We successfully apply our haptic interface in the optical-motion-capture master-slave system. The results of the needle insertion test showed that our haptic feedback can provide more safety than merely visual observation. We develop a suitable haptic device to produce both kinesthetic grasp force feedback and cutaneous push-pull force feedback. Our future research will include further objective performance evaluations of the optical-motion-capture master-slave robot system with our haptic interface in surgical scenarios.

  1. Definition and assessment of specific occupational demands concerning lifting, pushing, and pulling based on a systematic literature search.

    Science.gov (United States)

    Bos, J; Kuijer, P P F M; Frings-Dresen, M H W

    2002-12-01

    (1) To find a universal strategy for the identification of specific demands of a job or task, focusing on occupations in which there may be an increased risk for health complaints owing to these specific demands. (2) To select reliable and valid tests concerning lifting, pushing, and pulling, which consider the relation between occupational work demands and the assessment of the maximally acceptable load on an individual level. Literature search was performed using Medline (1988 to May 2001), Embase (1966 to May 2001), and NIOSHTIC (1971-98). No universal strategy was found for the definition of specific occupational demands. Therefore a "three step strategy" was formulated for defining specific occupational demands in a job or a task in order to prevent health complaints on an individual level. Many tests were found in the literature concerning lifting, but only a few concerning pushing and pulling. None of the tests concerning pushing, pulling, or lifting considered the relation between work demands and the assessment of the maximally acceptable load on an individual level. Furthermore, none of the tests met the criteria of reliability and prognostic value for musculoskeletal complaints completely. Only for the prognostic value of relative strength capacity tests concerning pushing pulling and lifting, did there appear to be limited proof for the development of musculoskeletal complaints. In general, for the prevention of work related health complaints, it can be suggested that more attention should be paid to: (1) the definition of specific occupational demands; (2) the assessment of specific occupational demands; and (3) the quality of tests for specific occupational demands.

  2. Push-pull tracer tests: Their information content and use for characterizing non-Fickian, mobile-immobile behavior

    Science.gov (United States)

    Hansen, Scott K.; Berkowitz, Brian; Vesselinov, Velimir V.; O'Malley, Daniel; Karra, Satish

    2016-12-01

    Path reversibility and radial symmetry are often assumed in push-pull tracer test analysis. In reality, heterogeneous flow fields mean that both assumptions are idealizations. To understand their impact, we perform a parametric study which quantifies the scattering effects of ambient flow, local-scale dispersion, and velocity field heterogeneity on push-pull breakthrough curves and compares them to the effects of mobile-immobile mass transfer (MIMT) processes including sorption and diffusion into secondary porosity. We identify specific circumstances in which MIMT overwhelmingly determines the breakthrough curve, which may then be considered uninformative about drift and local-scale dispersion. Assuming path reversibility, we develop a continuous-time-random-walk-based interpretation framework which is flow-field-agnostic and well suited to quantifying MIMT. Adopting this perspective, we show that the radial flow assumption is often harmless: to the extent that solute paths are reversible, the breakthrough curve is uninformative about velocity field heterogeneity. Our interpretation method determines a mapping function (i.e., subordinator) from travel time in the absence of MIMT to travel time in its presence. A mathematical theory allowing this function to be directly "plugged into" an existing Laplace-domain transport model to incorporate MIMT is presented and demonstrated. Algorithms implementing the calibration are presented and applied to interpretation of data from a push-pull test performed in a heterogeneous environment. A successful four-parameter fit is obtained, of comparable fidelity to one obtained using a million-node 3-D numerical model. Finally, we demonstrate analytically and numerically how push-pull tests quantifying MIMT are sensitive to remobilization, but not immobilization, kinetics.

  3. Beyond Technology Push vs. Demand Pull:The Evolution of Solar Policy in the U.S., Germany and China

    OpenAIRE

    Hansen, Erik Gunnar; Lüdeke-Freund, Florian; Quan, Xiahong; West, Joel

    2015-01-01

    To explain and promote the adoption of new technologies, researchers have debated the relative importance of technology push and demand pull factors (e.g., Schmookler, 1966; Mowery and Rosenberg, 1979; Peters et al, 2012). Here we examine a crucial problem of contemporary innovation policy — promoting the adoption of renewable energy to reduceanthropogenic global warming — that challenges prior models for large scale innovation adoption. From the recommendations of Mowery, Nelson and Martin (...

  4. Pickleworm (Diaphania nitidalis Cramer Neonate Feeding Preferences and the Implications for a Push-Pull Management System

    Directory of Open Access Journals (Sweden)

    Rosalie Leiner

    2016-07-01

    Full Text Available Push-pull cropping approaches for pest management target the oviposition behavior of adult females. However, insect larvae may move from the natal host and undermine the effectiveness of this approach. We investigated the longevity and feeding preference of pickleworm neonates (Diaphania nitidalis Cramer (Lepidoptera: Crambidae in relation to a potential push-pull cropping approach incorporating squash as a trap crop (pull and watermelon as a deterrent intercrop (push to protect a main crop of cantaloupe. Neonates could survive between 24 to 64 h without food, indicating they have some initial energy reserves to keep alive while in search of a suitable feeding site. To assess neonate feeding preferences, naive neonates were given the choice of five foods; leaves of squash, cantaloupe, watermelon, bean, and a pinto bean-based artificial diet. To assess if previous feeding experience influences neonate food source preference, neonates were allowed to feed on one of the five foods for 24 h and then given the same choice of the five food sources. The neonates, with or without previous feeding experience, did not appear to have a significant preference for any of the cucurbits: squash, cantaloupe, or watermelon, but they did prefer a cucurbit to the bean leaf or artificial diet. Feeding experience on one of these non-host foods made neonates more accepting of these food sources in the choice arena even when host plant food sources became available. It appears that neonate feeding preferences of pickleworm would neither hinder nor enhance the potential success of the proposed cucurbits to be used in a potential push-pull cropping approach for pickleworm management.

  5. Push or Pull: Changes in the Relative Risk and Growth of Entrepreneurship Among Older Households.

    Science.gov (United States)

    Weller, Christian E; Wenger, Jeffrey B; Lichtenstein, Benyamin; Arcand, Carolyn

    2016-11-03

    Amid insufficient retirement savings and the growing need to work longer, it is important to understand why self-employment, especially entrepreneurship, has grown among older households. Older households may have been pushed into entrepreneurship by the growing risks of wage-and-salary employment as wages and jobs have become less stable. Alternatively, older households may have been pulled into entrepreneurship as the associated risks have declined, for instance, due to greater opportunities to diversify income away from risky business income. We examine the economic causes of the rise in entrepreneurship among older households. We use summary statistics and multinomial logit regressions to analyze the link between economic pressures in wage-and-salary employment, financial strength of entrepreneurship, and the presence and change of entrepreneurship among older households-aged 50 years or older. We use household data from the Federal Reserve's Survey of Consumer Finances from 1989 to 2013. We find little support for the claim that increased economic pressures are correlated with rising entrepreneurship. Instead, our results suggest that the growth of older entrepreneurship is coincident with increasing access to dividend and interest income. We also find some evidence that access to Social Security and other annuity benefits increases the likelihood of self-employment. Entrepreneurship among older households increasingly correlates with income diversification. Policymakers interested in encouraging more entrepreneurship among older households could consider increased access to income diversification through social insurance. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Transition from pulled to pushed premixed turbulent flames due to countergradient transport

    Science.gov (United States)

    Sabelnikov, V. A.; Lipatnikov, A. N.

    2013-12-01

    The influence of countergradient transport on the speed of a statistically stationary, planar, 1D premixed flame that propagates in frozen turbulence is studied theoretically and numerically by considering the normalised magnitude NB of the countergradient flux to be an input parameter. Spectra of admissible flame speeds are analytically determined and explicit travelling wave solutions are found for two algebraic relations widely used to close the mean rate of product creation. A problem of selecting the physically relevant solution that is approached for sufficiently steep initial conditions is addressed. It is argued that, if NB is larger than an analytically determined critical number NcrB, then the type of the physically relevant solution is drastically changed. If NB pulled wave type, i.e. its speed is controlled by processes localised to the leading edge of the flame brush and can be determined within the framework of a linear analysis at the leading edge. If NB > NcrB, the physically relevant solution is of pushed wave type, i.e. its speed is controlled by processes in the entire flame brush. Analytical expressions for the speed of the physically relevant solution as a function of NB and the density ratio are obtained. For NB > NcrB, the mean flame brush thickness and the spatial profile of the Favre-averaged combustion progress variable are also determined analytically. These results are validated by numerical simulations. Both analytical expressions and numerical data indicate that (i) both turbulent flame speed and thickness are decreased when NB is increased and (ii) the direction of total scalar flux (i.e. the sum of countergradient and gradient contributions) is strongly affected not only by NB, but also by the shape of the dependence of the mean rate of product creation on the mean combustion progress variable.

  7. Large or small bore, push or pull: a comparison of three classes of percutaneous fluoroscopic gastrostomy catheters.

    Science.gov (United States)

    Kuo, Yuo-Chen; Shlansky-Goldberg, Richard D; Mondschein, Jeffrey I; Stavropoulos, S William; Patel, Aalpen A; Solomon, Jeffrey A; Soulen, Michael C; Kwak, Andrew; Itkin, Maxim; Chittams, Jesse L; Trerotola, Scott O

    2008-04-01

    To compare the tube performance and complication rates of small-bore, large-bore push-type, and large-bore pull-type gastrostomy catheters. A total of 160 patients (74 men, 86 women; mean age, 66.9 years, range, 22-95 y) underwent percutaneous fluoroscopic gastrostomy placement between January 2004 and March 2006. Choice of catheter was based on the preference of the attending radiologist. Data were collected retrospectively with institutional review board approval. Radiology reports provided information on the catheter, indication for gastrostomy, technical success, and immediate outcome. Chart review provided data on medical history, postprocedural complications, progress to feeding goal, and clinical outcomes. Statistical analysis was performed to compare the three classes of gastrostomy catheters. All 160 catheters were placed successfully. Patients who received small-bore catheters (14 F; n = 88) had significantly more tube complications (17% vs 5.6%) and were less likely to meet their feeding goal (P = .035) compared with patients with large-bore catheters (20 F; n = 72). No difference was observed in terms of major or minor complications. Large-bore push-type (n = 14) and pull-type catheters (n = 58) were similar in terms of complication rates. Patients who received large-bore push-type catheters achieved their feeding goals in significantly less time than those with large-bore pull-type catheters (average, 3.8 days vs 6.0 days; P = .04). Patients who received small-bore gastrostomy catheters are significantly more prone to tube dysfunction. Large-bore catheters should be preferentially used, with push-type catheters performing better with regard to the time to achieve feeding goal.

  8. Integrated pest management: the push-pull approach for controlling insect pests and weeds of cereals, and its potential for other agricultural systems including animal husbandry.

    Science.gov (United States)

    Hassanali, Ahmed; Herren, Hans; Khan, Zeyaur R; Pickett, John A; Woodcock, Christine M

    2008-02-12

    This paper describes the 'push-pull' or 'stimulo-deterrent diversionary' strategy in relation to current and potential examples from our own experiences. The push-pull effect is established by exploiting semiochemicals to repel insect pests from the crop ('push') and to attract them into trap crops ('pull'). The systems exemplified here have been developed for subsistence farming in Africa and delivery of the semiochemicals is entirely by companion cropping, i.e. intercropping for the push and trap cropping for the pull. The main target was a series of lepidopterous pests attacking maize and other cereals. Although the area given to the cereal crop itself is reduced under the push-pull system, higher yields are produced per unit area. An important spin-off from the project is that the companion crops are valuable forage for farm animals. Leguminous intercrops also provide advantages with regard to plant nutrition and some of the trap crops help with water retention and in reducing land erosion. A major benefit is that certain intercrop plants provide dramatic control of the African witchweed (striga). Animal husbandry forms an essential part of intensive subsistence agriculture in Africa and developments using analogous push-pull control strategies for insect pests of cattle are exemplified.

  9. Habitat discrimination by gravid Anopheles gambiae sensu lato--a push-pull system.

    Science.gov (United States)

    Herrera-Varela, Manuela; Lindh, Jenny; Lindsay, Steven W; Fillinger, Ulrike

    2014-04-02

    . Although the study was not designed to distinguish between stimuli that acted over a distance or on contact, it could be demonstrated that the choice of habitat is mediated by chemical cues based on both preference and avoidance. These cues, if identified, might be developed for 'push-pull' strategies to improve malaria vector monitoring and control.

  10. Redox-switchable second-order nonlinear optical responses of push-pull monotetrathiafulvalene-metalloporphyrins.

    Science.gov (United States)

    Liu, Chun-Guang; Guan, Wei; Song, Ping; Yan, Li-Kai; Su, Zhong-Min

    2009-07-20

    The redox-active tetrathiafulvalene (TTF) is a good electron donor, and porphyrin is highly delocalized in cyclic pi-conjugated systems. The direct combination of the two interesting building units into the same molecule provides an intriguing molecular system for designing nonlinear optical (NLO) molecular materials. In the present paper, the second-order NLO properties of a series of monoTTF-porphyrins and metalloporphyrins have been calculated by density functional theory (DFT) combined with the finite field (FF) method. Our calculations show that these compounds possess considerably large static first hyperpolarizabilities, approximately 400 x 10(-30) esu. Since the TTF unit is able to exist in three different stable redox states (TTF, TTF(*+), and TTF(2+)), the redox switching of the NLO response of the zinc(II) derivative of monoTTF-metalloporphyrin has been studied, and a substantial enhancement in static first hyperpolarizability has been obtained in its oxidized species according to our DFT-FF calculations. The beta values of one- and two-electron-oxidized species are 3.6 and 8.7 times as large as that of the neutral compound, especially for two-electron-oxidized species, with a value of 3384 x 10(-30) esu. This value is about 3 times that for a push-pull metalloporphyrin, which has an exceptionally large hyperpolarizability among reported organic NLO chromophores. Meanwhile, to give a more intuitive description of band assignments of the electron spectrum and trends in NLO behavior of these compounds, the time-dependent (TD)DFT method has been adopted to calculate the electron spectrum. The TDDFT calculations well-reproduce the soret band and Q-type bands of the monoTTF-porphyrin, and these absorption bands can be assigned to the pi --> pi* transition of the porphyrin core. On the other hand, the oxidized process significantly affects the geometrical structures of the TTF unit and porphyrin ring, and the two-electron-oxidized species has a planar TTF unit

  11. Bulk charge carrier transport in push-pull type organic semiconductor.

    Science.gov (United States)

    Karak, Supravat; Liu, Feng; Russell, Thomas P; Duzhko, Volodimyr V

    2014-12-10

    Operation of organic electronic and optoelectronic devices relies on charge transport properties of active layer materials. The magnitude of charge carrier mobility, a key efficiency metrics of charge transport properties, is determined by the chemical structure of molecular units and their crystallographic packing motifs, as well as strongly depends on the film fabrication approaches that produce films with different degrees of anisotropy and structural order. Probed by the time-of-flight and grazing incidence X-ray diffraction techniques, bulk charge carrier transport, molecular packing, and film morphology in different structural phases of push-pull type organic semiconductor, 7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bithiophen]-5yl)benzo[c][1,2,5] thiadiazole), one of the most efficient small-molecule photovoltaic materials to-date, are described herein. In the isotropic phase, the material is ambipolar with high mobilities for a fluid state. The electron and hole mobilities at the phase onset at 210.78 °C are 1.0 × 10(-3) cm(2)/(V s) and 6.5 × 10(-4) cm(2)/(V s), respectively. Analysis of the temperature and electric field dependences of the mobilities in the framework of Gaussian disorder formalism suggests larger energetic and positional disorder for electron transport sites. Below 210 °C, crystallization into a polycrystalline film with a triclinic unit cell symmetry and high degree of anisotropy leads to a 10-fold increase of hole mobility. The mobility is limited by the charge transfer along the direction of branched alkyl side chains. Below 90 °C, faster cooling rates produce even higher hole mobilities up to 2 × 10(-2) cm(2)/(V s) at 25 °C because of the more isotropic orientations of crystalline domains. These properties facilitate in understanding efficient material performance in photovoltaic devices and will guide further development of materials and devices.

  12. Evaluation of a peridomestic mosquito trap for integration into an Aedes aegypti (Diptera: Culicidae) push-pull control strategy.

    Science.gov (United States)

    Salazar, Ferdinand V; Achee, Nicole L; Grieco, John P; Prabaripai, Atchariya; Eisen, Lars; Shah, Pankhil; Chareonviriyaphap, Theeraphap

    2012-06-01

    We determined the feasibility of using the BG-Sentinel™ mosquito trap (BGS) as the pull component in a push-pull strategy to reduce indoor biting by Aedes aegypti. This included evaluating varying numbers of traps (1-4) and mosquito release numbers (10, 25, 50, 100, 150, 200, and 250) on recapture rates under screen house conditions. Based on these variations in trap and mosquito numbers, release intervals were rotated through a completely randomized design with environmental factors (temperature, relative humidity, and light intensity) and monitored throughout each experiment. Data from four sampling time points (05:30, 09:30, 13:30, and 17:30) indicate a recapture range among treatments of 66-98%. Furthermore, 2-3 traps were as effective in recapturing mosquitoes as 4 traps for all mosquito release numbers. Time trends indicate Day 1 (the day the mosquitoes were released) as the "impact period" for recapture with peak numbers of marked mosquitoes collected at 09:30 or 4 h post-release. Information from this study will be used to guide the configuration of the BGS trap component of a push-pull vector control strategy currently in the proof-of-concept stage of development in Thailand and Peru.

  13. Oviposition Preferences of Pickleworm (Lepidoptera: Crambidae) in Relation to a Potential Push-Pull Cropping Management Approach.

    Science.gov (United States)

    Leiner, R C; Spafford, H

    2016-04-25

    Pickleworm, Diaphania nitidalis Cramer (Lepidoptera: Crambidae), is a major pest of cucurbits. The current management approach for this pest is weekly insecticide applications. A push-pull cropping approach may be an alternative management practice and could reduce reliance on pesticides. One potential push-pull scenario is the use of squash (Cucurbita pepo L.) as a trap crop and watermelon (Citrullus lanatus [Thunb.] Matsum. & Nakai) as a deterrent intercrop to manage pickleworm on cantaloupe (Cucumis melo L.). This study investigated if the underlying mechanism required for the success of this management approach (a female oviposition preference or nonpreference among squash, cantaloupe, and watermelon) is present. A series of oviposition preference experiments was conducted to see how individual females responded when presented with different host plants for oviposition. Under laboratory conditions, when females had the choice of a leaf from squash, cantaloupe, and watermelon, they laid a higher proportion of their eggs on the cantaloupe leaf. However, under greenhouse conditions, when females were presented with whole plants of the three different species, they laid a higher percent of their eggs on the squash plant. Females laid a similar number of eggs on watermelon as compared with cantaloupe under greenhouse conditions, and appeared to not be averse to laying their eggs on watermelon. However, when presented with a noncucurbit, such as bean, females laid a low number of total eggs. Overall, it appears that squash may be more preferred as an oviposition substrate than cantaloupe or watermelon and may be a useful trap crop or pull. Further study to determine a suitable deterrent intercrop or push and evaluation of the proposed system under field conditions are needed. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Push, pull, and plant: the personal side of physician immigration to alberta, Canada

    National Research Council Canada - National Science Library

    Klein, Douglas; Hofmeister, Marianna; Lockyear, Jocelyn; Crutcher, Rodney; Fidler, Herta

    2009-01-01

    ... licenses for less than 7 years. Three major themes were identified. The first was the "push" from their own country of origin and their perception that moving to Alberta would be better for them...

  15. In vivo measurement of extravasation of silver nanoparticles into liver extracellular space by push-pull-based continuous monitoring system.

    Science.gov (United States)

    Su, Cheng-Kuan; Hung, Ching-Wen; Sun, Yuh-Chang

    2014-06-05

    With the increasing prevalence of silver nanoparticles (AgNPs) in various products, whether such AgNPs will introduce new injury mechanisms from new pathologies remains to be determined. From the toxicokinetic viewpoint, it is vital to have in-depth knowledge of their in vivo transport kinetics and extravasation phenomenon. By combining push-pull perfusion sampling, in-tube solid phase extraction, and inductively coupled plasma mass spectrometry, we used an in vivo push-pull-based continuous monitoring system to investigate in vivo transport kinetics of extracellular AgNPs in living rat liver with a detection limit and temporal resolution of 0.64μgL(-1) and 10min, respectively. Before administration into living rats, the pre-incubation in DMEM with 10% FBS for 8h was adopted as the optimized exposure condition for the used AgNPs. After repeated-dose treatments, we observed a higher concentration of AgNPs in the liver extracellular space, suggesting that AgNP clearance by the reticuloendothelial system (RES) may be blocked by a prior administration of AgNPs. Future studies on AgNP distribution in different liver compartments (blood stream, extracellular space and Kupffer cells/hepatocytes) are necessary for defining the risks and benefits of AgNP applications.

  16. Potential Push-pull Factors to Introduce Takaful (Islamic Insurance as a New Product in India: Preliminary Overview

    Directory of Open Access Journals (Sweden)

    Syed Ahmed Salman

    2014-11-01

    Full Text Available The objective of this study is to explore on the potential push-pull factors to introduce Takaful in India. Nowadays, insurance becomes the backbone of our daily life since it will help us in the case of misfortune. The concept of insurance is acceptable since it is based on the noble idea. However, its practices become questionable from the religious aspect due to the involvement of interest, uncertainty and gambling. As an alternative, Takaful has been introduced and it has been widely spread in both Muslim and non-Muslim countries. In India, Takaful has not been offered yet. Due to its potential in India, this study explores the possibilities of introducing it. The findings show that the pushing factor, i.e., innovative nature of the potential customers and the pulling factors such as cost vs. benefit, assess-ability, availability and service quality, product features, reputation of the company, attribute of agent, marketing and promotion and social and religious factors are in favor to introduce Takaful in India.

  17. Reactivity of Hontomín carbonate rocks to acidic solution injection: reactive "push-pull" tracer tests results

    Science.gov (United States)

    De Gaspari, Francesca; Cabeza, Yoar; Luquot, Linda; Rötting, Tobias; Saaltink, Maarten W.; Carrera, Jesus

    2014-05-01

    Several field tests will be carried out in order to characterize the reservoir for CO2 injection in Hontomín (Burgos, Spain) as part of the Compostilla project of "Fundación Ciudad de la Energía" (CIUDEN). Once injected, the dissolution of the CO2 in the resident brine will increase the acidity of the water and lead to the dissolution of the rocks, constituted mainly by carbonates. This mechanism will cause changes in the aquifer properties such as porosity and permeability. To reproduce the effect of the CO2 injection, a reactive solution with 2% of acetic acid is going to be injected in the reservoir and extracted from the same well (reactive "push-pull" tracer tests) to identify and quantify the geochemical reactions occurring into the aquifer. The reactivity of the rock will allow us also to evaluate the changes of its properties. Previously, theoretical calculations of Damkhöler numbers were done to determine the acid concentrations and injection flow rates needed to generate ramified-wormholes patterns, during theses "push-pull" experiments. The aim of this work is to present the results and a preliminary interpretation of the field tests.

  18. Incorporation of a platinum center in the pi-conjugated core of push-pull chromophores for nonlinear optics (NLO).

    Science.gov (United States)

    Durand, Raphaël J; Gauthier, Sébastien; Achelle, Sylvain; Kahlal, Samia; Saillard, Jean-Yves; Barsella, Alberto; Wojcik, Laurianne; Le Poul, Nicolas; Robin-Le Guen, Françoise

    2017-02-28

    In this article, we describe the synthesis, redox characteristics, and linear and nonlinear optical (NLO) properties of seven new unsymmetrical push-pull diacetylide platinum-based complexes. These D-π-Pt-π-A complexes incorporate pyranylidene ligands as pro-aromatic donor groups (D), diazine rings as electron-withdrawing groups (A), and various aromatic fragments (styryl or thienylvinyl) as π-linkers separating the platinum diacetylide unit from the donor and the acceptor groups. This is one of the first examples of push-pull chromophores incorporating a platinum center in the π-conjugated core. The NLO properties of these complexes were compared with those of their purely organic analogues. All compounds (organic and organometallic) exhibited positive μβ values, which dramatically increased upon methylation of the pyrimidine fragment. However, this increase was even more significant in the complexes due to the presence of platinum in the π-conjugated core. The effects of the linker on the redox and spectroscopic properties of the complexes are also discussed. In addition, DFT calculations were performed in order to gain further insight into the intramolecular charge transfer (ICT) occurring through the platinum center.

  19. Evaluation of a push-pull strategy for the management of Frankliniella bispinosa (Thysanoptera: Thripidae) in bell peppers.

    Science.gov (United States)

    Tyler-Julian, Kara; Funderburk, Joe; Frantz, Galen; Mellinger, Charles

    2014-10-01

    A push-pull strategy for managing the anthophilous Frankliniella bispinosa (Morgan) in pepper and increasing conservation biological control was evaluated. Push components of ultraviolet (UV)-reflective mulch and foliar applications of kaolin and the pull component of sunflower companion plants were evaluated in replicated field experiments in 2011 and 2012. Adult F. bispinosa rapidly colonized and reproduced in the peppers and sunflowers during early flowering, but populations declined later, as numbers of the predatory Orius insidiosus (Say) and Orius pumilio (Champion) increased in both hosts. Numbers of F. bispinosa were reduced by kaolin during early pepper flowering. Thrips numbers were increased on some of the later sample dates, apparently due to reduced predation that resulted from negative effects of kaolin and UV-reflective mulch on Orius populations. Numbers of thrips increased in peppers with companion plants during the first week of flowering each year, followed by declines in thrips numbers during the next 2 wk in 2011. There was little effect each year of the companion plants on the numbers of Orius in the pepper flowers. There was one date in 2011 and no dates in 2012 in which UV-reflective mulch or kaolin acted in concert with the presence of the companion plants to reduce thrips numbers in the main crop of pepper. Yield effects were not attributed to thrips damage. We conclude that sunflower companion plants did not act additively or synergistically with kaolin or UV-reflective mulch to reduce thrips and increase Orius populations in pepper.

  20. Push-pull macrocycles: donor-acceptor compounds with paired linearly conjugated or cross-conjugated pathways.

    Science.gov (United States)

    Leu, Wade C W; Fritz, Amanda E; Digianantonio, Katherine M; Hartley, C Scott

    2012-03-01

    Two-dimensional π-systems are of current interest in the design of functional organic molecules, exhibiting unique behavior for applications in organic electronics, single-molecule devices, and sensing. Here we describe the synthesis and characterization of "push-pull macrocycles": electron-rich and electron-poor moieties linked by a pair of (matched) conjugated bridges. We have developed a two-component macrocyclization strategy that allows these structures to be synthesized with efficiencies comparable to acyclic donor-bridge-acceptor systems. Compounds with both cross-conjugated (m-phenylene) and linearly conjugated (2,5-thiophene) bridges have been prepared. As expected, the compounds undergo excitation to locally excited states followed by fluorescence from charge-transfer states. The m-phenylene-based systems exhibit slower charge-recombination rates presumably due to reduced electronic coupling through the cross-conjugated bridges. Interestingly, pairing the linearly conjugated 2,5-thiophene bridges also slows charge recombination. DFT calculations of frontier molecular orbitals show that the direct HOMO-LUMO transition is polarized orthogonal to the axis of charge transfer for these symmetrical macrocyclic architectures, reducing the electronic coupling. We believe the push-pull macrocycle design may be useful in engineering functional frontier molecular orbital symmetries.

  1. TDDFT investigation of the electronic structures and photophysical properties of fluorescent extended styryl push-pull chromophores containing carbazole unit.

    Science.gov (United States)

    Gupta, Vinod D; Tathe, Abhinav B; Padalkar, Vikas S; Patil, Vikas S; Phatangare, Kiran R; Umape, Prashant G; Ramasami, Ponnadurai; Sekar, Nagaiyan

    2013-11-01

    Push-pull chromophores attached to carbazole based π-conjugating spacers bearing N-alkylamino donors, cyanovinyl and carbethoxy acceptors have been studied by the means of UV-Visible measurements. The intramolecular charge transfer (ICT) of these π-conjugated systems has also been tested by investigating the ability of the solute molecules to undergo shifts in their fluorescence emission maxima with increasing solvent polarity. Density Functional Theory [B3LYP/6-31G(d)] and Time Dependent Density Functional Theory [TD-B3LYP/6-31G(d)] computations have been used to have more understanding of the structural, molecular, electronic and photophysical parameters of push-pull dyes. The largest wavelength difference between the experimental and computed electronic absorption maxima was 45 nm. For emission, a largest difference of 61 nm was observed. The ground state and excited state dipole moments in different solvents were determined using experimental solvatochromic data and computed Onsager radii. The dipole moments of the molecules in the excited state were observed to be higher than in the ground state.

  2. Structural effects on the photoelectrochemical properties of new push-pull dyes based on vinazene acceptor triphenylamine donor

    Science.gov (United States)

    Arcos, Wilmmer A.; Guimarães, Robson R.; Insuasty, Braulio; Araki, Koiti; Ortiz, Alejandro

    2016-05-01

    The push-pull behavior of novel dyes, based on vinazene electron-acceptor groups linked to arrays of triphenylamine (TPA) electron-donor group, was studied by electronic absorption and emission spectroscopy, as well as by cyclic voltammetry. The most stable ground state structure and their electronic properties were modeled by density functional theory (DFT) calculations using the B3LYP functional and 6-31G++ basis set, whereas the electronic properties in the excited states were calculated by TD-DFT, under the same functional and basis set, using SCF and PCM methods. The theoretical calculations matched well with experimental data, showing that λmax of the lowest energy absorption band can be assigned to an intramolecular charge transfer transition. In fact, the HOMO and LUMO are respectively localized on the TPA donor and the dicyanomethylene acceptor moiety confirming a remarkable push-pull character. Photoelectrochemical cells parameters were correlated with dyes structural properties showing to be consistent with the anchoring through the nitrogen atoms of CN groups. The nature of the donor-acceptor groups, conformation and number of anchoring CN groups (2 seems to be the best) strongly influenced the overall efficiency of dye sensitized solar cells.

  3. Structure-property relationships in push-pull amino/cyanovinyl end-capped oligothiophenes: quantum chemical and experimental studies.

    Science.gov (United States)

    Oliva, María Moreno; Casado, Juan; Raposo, M Manuela M; Fonseca, A Maurício C; Hartmann, Horst; Hernández, Víctor; López Navarrete, Juan T

    2006-09-29

    A series of push-pull chromophores built around thiophene-based pi-conjugating spacers and bearing various types of amino donors and cyanovinyl acceptors have been analyzed by means of UV-vis-NIR, IR, and Raman spectroscopic measurements in the solid state as well as in solution. The intramolecular charge transfer (ICT) of these pi-conjugated systems has also been tested by analyzing the ability of the solute molecules to undergo shifts in their fluorescence emission maxima with increasing solvent polarity. These push-pull oligomers also display an attractive electrochemical behavior since they generate stable species both upon oxidation and reduction. Oxidation mainly involves changes in the electron-rich aminooligothienyl half-part of the molecule and leads to the formation of stable cations. On the other hand, reduction to radical anions and dianions is mainly cyanovinyl-centered but also affects the pi-conjugated electron relay. Density functional theory (DFT) calculations have been carried out to help the assignment of the most relevant electronic and vibrational features and to derive useful information about the molecular structure of these NLO-phores.

  4. Coherent Population Trapping Resonances in Buffer Gas-filled Cs Vapor Cells with Push-Pull Optical Pumping

    CERN Document Server

    Liu, Xiaochi; Guérandel, Stéphane; Gorecki, Christophe; de Clercq, Emeric; Boudot, Rodolphe

    2013-01-01

    We report on a theoretical study and experimental characterization of coherent population trapping (CPT) resonances in buffer gas-filled vapor cells with push-pull optical pumping (PPOP) on Cs D1 line. We point out that the push-pull interaction scheme is identical to the so-called lin per lin polarization scheme. Expressions of the relevant dark states, as well as of absorption, are reported. The experimental setup is based on the combination of a distributed feedback (DFB) diode laser, a pigtailed intensity Mach-Zehnder electro-optic modulator (MZ EOM) for optical sidebands generation and a Michelson-like interferometer. A microwave technique to stabilize the transfer function operating point of the MZ EOM is implemented for proper operation. A CPT resonance contrast as high as 78% is reported in a cm-scale cell for the magnetic-field insensitive clock transition. The impact of the laser intensity on the CPT clock signal key parameters (linewidth - contrast - linewidth/contrast ratio) is reported for three ...

  5. Push-pull receptive field organization and synaptic depression: Mechanisms for reliably encoding naturalistic stimuli in V1

    Directory of Open Access Journals (Sweden)

    Jens eKremkow

    2016-05-01

    Full Text Available Neurons in the primary visual cortex are known for responding vigorously but with high variability to classical stimuli such as drifting bars or gratings. By contrast, natural scenes are encoded more efficiently by sparse and temporal precise spiking responses. We used a conductance-based model of the visual system in higher mammals to investigate how two specific features of the thalamo-cortical pathway, namely push-pull receptive field organization and synaptic depression, can contribute to this contextual reshaping of V1 responses. By comparing cortical dynamics evoked respectively by natural vs. artificial stimuli in a comprehensive parametric space analysis, we demonstrate that the reliability and sparseness of the spiking responses during natural vision is not a mere consequence of the increased bandwidth in the sensory input spectrum. Rather, it results from the combined impacts of synaptic depression and push-pull inhibition, the later acting for natural scenes as a form of effective feed-forward inhibition as demonstrated in other sensory systems. Thus, the combination of feedforward-like inhibition with fast thalamo-cortical synaptic depression by simple cells receiving a direct structured input from thalamus composes a generic computational mechanism for generating a sparse and reliable encoding of natural sensory events.

  6. Quantification of the push-pull Effect in disubstituted alkynes - Application of occupation quotients π*/π and 13C chemical shift differences ΔδCtbnd C

    Science.gov (United States)

    Kleinpeter, Erich; Klaumünzer, Ute

    2014-09-01

    Structures, 13C chemical shifts, and the occupation quotients of anti-bonding π* and bonding π orbitals of the Ctbnd C triple bond along a series of push-pull alkynes (p)Xsbnd C6H4sbnd C(O)sbnd Ctbnd Csbnd NHsbnd C6H4sbnd Y(p) (X,Y = H, Me, OMe, NMe2, NO2, COMe, COOMe, F, Cl, Br) were computed at the DFT level (B3LYP/6-311G**) of theory. Both the stereochemistry (cis/trans-isomers) by steric twist and the push-pull character by both 13C chemical shift differences (ΔδCtbnd C) and the occupation quotient (π*Ctbnd C/πCtbnd C) were studied; the latter two parameters can be readily employed to precisely quantify the push-pull effect in alkynes.

  7. Push-pull electron effects of the complexant in a Li atom doped molecule with electride character: a new strategy to enhance the first hyperpolarizability.

    Science.gov (United States)

    Liu, Zhen-Bo; Zhou, Zhong-Jun; Li, Ying; Li, Zhi-Ru; Wang, Rong; Li, Qing-Zhong; Li, Yang; Jia, Feng-Yan; Wang, Yin-Feng; Li, Zong-Jun; Cheng, Jian-Bo; Sun, Chia-Chung

    2010-09-21

    Differing from the reported strategy of push or pull electron effects of the complexant, a new strategy of the combination effects of both push and pull electrons of the complexant to enhance the first hyperpolarizability is performed with two Li atom doped complexants with a pair of difluorophenyl subunit rings. Large variance of the static first hyperpolarizabilities (beta(0)) are exhibited at the MP2/6-311++G(d,p) level. The order of the beta(0) values is 2.9 x10(2) (complexant UD) push-pull electronic effect of the complexant has the largest beta(0). The edge-type push-pull electronic effect brings a 2700 times increase in the beta(0) from the UD to H(F)-L(F) structure. It shows that the push-pull electronic effect is a highly effective strategy to enhance the beta(0) value. The beta(0) (7.8 x 10(5) a.u.) of the H(F)-L(F) is considerable, due to the small DeltaE and the very large Delta mu (18.085 a.u.), which comes from the corresponding long-range charge transfer transition. It is interesting that a pair of subunit rings of the complexant may have different electronic effects. In H-L and H(F)-L(F), the left ring with a longer distance between Li and the subunit ring exhibits a push electronic effect, while the right ring with the shorter distance exhibits a pull electronic effect. This work may contribute to the development of potential high-performance nonlinear optical materials.

  8. Standardizing Ammunition Distribution within the United States Navy as either a Push or Pull Methodology

    Science.gov (United States)

    2012-06-01

    TPS Toyota Production System VERTREP Vertical Replenishment VMI Vendor Managed Inventory xiv THIS PAGE INTENTIONALLY LEFT BLANK xv...shipments, this push-based system is called a Vendor Managed Inventory ( VMI ). VMI has advantages in potential inventory reduction because of just in time...the supplier and retailer for this type of system to work. As will be discussed later in this project, the element of trust is necessary for a VMI

  9. The anomaly in a breakthrough curve of a single well "push-pull" tracer test: A density driven effect?

    Science.gov (United States)

    Zeilfelder, Sarah; Hebig, Klaus; Ito, Narimitsu; Machida, Isao; Scheytt, Traugott; Marui, Atsunao

    2013-04-01

    What method is appropriate to investigate an aquifer when there is only one well available? A single well "push-pull" tracer test (PP Test) may be a suitable method in order to characterize an aquifer and to obtain information about the hydraulic and chemical properties when only one well is available for the investigations. In a PP test, a test solution that contains a known amount of solutes and a conservative tracer is injected into the aquifer ("push") and extracted afterwards ("pull"). Optionally, the test solution is flushed out of the well and the casing with untreated test solution with a so called "chaser" before being extracted. Also between the injection and the extraction phase a drifting time may be included. The breakthrough of the tracer during the extraction phase is measured and used for analyses and interpretation. In the last three years, several PP Test campaigns were conducted at two different test sites in Japan (Hebig et al. 2011, Zeilfelder et al. 2012). The aim was to investigate the applicability of the PP Test method in different geological settings and in different types of aquifers. The latest field campaign thus focussed on the question how variations of the setup are influencing the breakthrough curve of the PP Test in order to develop and enhance this method. Also the standardization of the PP Test was an aim of this study. During the campaign, a total of seven PP Tests were performed, while only single aspects of the setup were varied from test to test. The tests differed in injection and extraction rate, in the salinity of the injected test solution and in the use of a chaser solution. The general shapes of the breakthrough curves were similar and conclusions about the repeatability of the PP Test could be drawn. However, a sharp anomaly was observed in the breakthrough curve of one specific setup type. By repeating this PP test under the same boundary conditions, we were able to recreate the anomaly and could exclude any technical

  10. Reflection Band Control of Inverse Opal Film with Photoresponse Properties of Push-Pull Type Azobenzene LC Polymers

    Directory of Open Access Journals (Sweden)

    Sunnam Kim

    2008-01-01

    Full Text Available DcAz2Mc and DR1Mc molecules having push-pull type of azobenzene groups are synthesized, and their photo-orientational behaviors are investigated in the polymer system. In order to understand the relationship between a molecular structure and its physical properties, electronic structure calculation is computationally carried out. Regarding to their photo response properties, the copolymers of poly(DcAz2Mc-co-M6PBMe and poly(DR1Mc-co-M6PBMe are infiltrated into inverse opal films, and Bragg reflection shifts are observed under photostimuli. When the linearly polarized light is irradiated, Bragg reflection bands are shifted to the longer wavelength region as reflective index increases.

  11. Tailoring the spacer type and length in push-pull chromophores. Insights from a systematic theoretical study

    Science.gov (United States)

    Kerkines, Ioannis S. K.; Lathiotakis, Nektarios N.; Theodorakopoulos, Giannoula; Petsalakis, Ioannis D.

    2016-06-01

    The predicting ability of Mulliken-type formulae in estimating the charge-transfer (CT) excitation energy in ;push-pull; donor-bridge-acceptor (D-B-A) systems is evaluated systematically by tailoring the length of an oligoenic spacer bridge separating an N,N-dimethylanilino (DMA) donor and a dicyanovinyl (DCV) acceptor. In order to achieve satisfactory agreement with time-dependent density functional theory (TDDFT) values, the D⋯A distance and charge separation inside the D-B-A system are replaced with rigorously calculated ;effective; values, while using ;superdonor-superacceptor; energetics. The proposed modified Mulliken formula has the potential to be of significant assistance for cases when direct TDDFT calculation of the CT state is unfeasible.

  12. Theoretical studies on NLO properties of push-pull multi-cycle electro-optical polymer intermediates including thiophene ring

    Institute of Scientific and Technical Information of China (English)

    付伟; 封继康; 于坤千; 任爱民; 王江洪; 沈玉全

    2000-01-01

    The second-order nonlinear optical susceptiblities βuk, βμ and third-order non-linear optical susceptibilities γijkl, (γ〉 of a series of the novel push-pull multi-ring eletro- photo polymer intermediates have been calculated. The influences of molecular structure, donor, acceptor and the frequency of external field onβandγ, and the relationship betweenγand the number of thiophene rings ( i. e. conjugated chain length) have been studied using INDO/SCI methods combined with sum-over-state(SOS) formula. The calculated results show that γ is proportional to 2.69 power of the chain length of the conjugated molecular bonds when the length is not quite long.

  13. And yet they glow: thiazole based push-pull fluorophores containing nitro groups and the influence of regioisomerism

    Science.gov (United States)

    Habenicht, Stefanie H.; Siegmann, Michael; Kupfer, Stephan; Kübel, Joachim; Weiß, Dieter; Cherek, Doreen; Möller, Uwe; Dietzek, Benjamin; Gräfe, Stefanie; Beckert, Rainer

    2015-06-01

    Reported is a study on the influence of regioisomerism on the photophysical properties in 4-hydroxy-1,3-thiazole-based push-pull-chromophores/fluorophores to evaluate the molecular structure-property relationship as a basic foundation for future design strategies concerning this class of dyes. Surprisingly, the nitro groups used as acceptors do not act as a fluorescence quencher, instead the derivatives synthesized exhibit quantum yields of 37-40%. Two 4-ethoxy-1,3-thiazole derivatives which differ only in the positioning of their electron donating (methoxy) and electron withdrawing (nitro) groups have been synthesized and examined in terms of their photophysical properties, i.e. UV/Vis absorption and fluorescence emission spectra. Additionally, quantum chemical calculations have been performed to unravel the underlying fundamental transitions and to explain the experimental results.

  14. Synthetic Control of the Excited-State Dynamics and Circularly Polarized Luminescence of Fluorescent "Push-Pull" Tetrathia[9]helicenes.

    Science.gov (United States)

    Yamamoto, Yuki; Sakai, Hayato; Yuasa, Junpei; Araki, Yasuyuki; Wada, Takehiko; Sakanoue, Tomo; Takenobu, Taishi; Kawai, Tsuyoshi; Hasobe, Taku

    2016-03-14

    A series of fluorescent "push-pull" tetrathia[9]helicenes based on quinoxaline (acceptor) fused with tetrathia[9]helicene (donor) derivatives was synthesized for control of the excited-state dynamics and circularly polarized luminescence (CPL) properties. In this work, introduction of a quinoxaline onto the tetrathia[9]helicene skeleton induced the "push-pull" character, which was enhanced by further introduction of an electron-releasing Me2 N group or an electron-withdrawing NC group onto the quinoxaline unit (denoted as Me2 N-QTTH and NC-QTTH, respectively). These trends were successfully discussed in terms of by electrochemical measurements and density functional theory (DFT) calculations. As a consequence, significant enhancements in the fluorescence quantum yields (ΦFL ) were achieved. In particular, the maximum ΦFL of Me2 N-QTTH was 0.43 in benzene (NC-QTTH: ΦFL =0.30), which is more than 20 times larger than that of a pristine tetrathia[9]helicene (denoted as TTH; ΦFL =0.02). These enhancements were also explained by kinetic discussion of the excited-state dynamics such as fluorescence and intersystem crossing (ISC) pathways. Such significant enhancements of the ΦFL values thus enabled us to show the excellent CPL properties. The value of anisotropy factor gCPL (normalized difference in emission of right-handed and left-handed circularly polarized light) was estimated to be 3.0 × 10(-3) for NC-QTTH. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Sequential push-pull pumping mechanism for washing and evacuation of an immunoassay reaction chamber on a microfluidic CD platform.

    Directory of Open Access Journals (Sweden)

    Tzer Hwai Gilbert Thio

    Full Text Available A centrifugal compact disc (CD microfluidic platform with reservoirs, micro-channels, and valves can be employed for implementing a complete immunoassay. Detection or biosensor chambers are either coated for immuno-interaction or a biosensor chip is inserted in them. On microfluidic CDs featuring such multi-step chemical/biological processes, the biosensor chamber must be repeatedly filled with fluids such as enzymes solutions, buffers, and washing solutions. After each filling step, the biosensor chamber needs to be evacuated by a passive siphoning process to prepare it for the next step in the assay. However, rotational speed dependency and limited space on a CD are two big obstacles to performing such repetitive filling and siphoning steps. In this work, a unique thermo-pneumatic (TP Push-Pull pumping method is employed to provide a superior alternative biosensor chamber filling and evacuation technique. The proposed technique is demonstrated on two CD designs. The first design features a simple two-step microfluidic process to demonstrate the evacuation technique, while the second design shows the filling and evacuation technique with an example sequence for an actual immunoassay. In addition, the performance of the filling and evacuation technique as a washing step is also evaluated quantitatively and compared to the conventional manual bench top washing method. The two designs and the performance evaluation demonstrate that the technique is simple to implement, reliable, easy to control, and allows for repeated push-pulls and thus filling and emptying of the biosensor chamber. Furthermore, by addressing the issue of rotational speed dependency and limited space concerns in implementing repetitive filling and evacuation steps, this newly introduced technique increases the flexibility of the microfluidic CD platform to perform multi-step biological and chemical processes.

  16. Salt Marsh sediment 15N/13C "Push-Pull" assays reveal coupled sulfur, nitrogen, and carbon cycling

    Science.gov (United States)

    Thomas, S. M.; Tucker, J.; Thomas, F.; Sievert, S. M.; Cardon, Z. G.; Giblin, A. E.

    2016-12-01

    Salt marshes are extraordinarily productive ecosystems found in estuaries worldwide, hosting intensive sulfur, nitrogen, and carbon cycling. Although it has been hypothesized that in this environment sulfur oxidation may be important for energy flow, there is little direct data. At the heart of these hypothesized interactions are sulfur oxidizing microbes. Sulfur oxidizers can catalyze sulfide (re-)oxidation with nitrate as the electron acceptor under anaerobic conditions, producing ammonium (via DNRA) or dinitrogen gas (via denitrification). The form of sulfur present in marsh systems influences whether autotrophic or heterotrophic processes transform nitrate either to dinitrogen gas or ammonium through DNRA. To examine the fate of nitrate and interactions with sulfur, we conducted a series of "push-pull" experiments in marsh sediment at the Plum Island Ecosystems Long-Term Ecological Research site in Massachusetts. Porewater was extracted anoxically and amended with isotopically labeled nitrate (15N) and bicarbonate (13C). Porewater was pumped back into the sediment and then withdrawn at intervals of several hours. Dissolved inorganic nitrogen, sulfur, and carbon were measured as well as isotopes of nitrogen gas and ammonium. These push-pull experiments were conducted at several times during the growing season, to coincide with salt marsh grass initial growth (May), maximum growth (July), flowering (August), and senescence (October). Porewater sulfides were very low to non-detectable in May (time of initial plant growth) and increased to a maximum of 3 mM in October (time of plant senescence). Combined rates of denitrification and DNRA also varied seasonally: rates were higher in May (0.16 - 17.5 nmoles N/cm3/hr) and much lower in October (0 - 0.03 nmoles N/cm3/hr). Interestingly, DNRA rates were always higher than denitrification rates, often by an order of magnitude or more.

  17. In-Situ Quantification of Methanotrophic Activity in a Landfill Cover Soil Using Gas Push-Pull Tests

    Science.gov (United States)

    Gomez, K. E.; Gonzalez-Gil, G.; Schroth, M. H.; Zeyer, J.

    2007-12-01

    Landfills are both a major anthropogenic source and a sink for the greenhouse gas CH4. Methanogenic bacteria produce CH4 during the anaerobic digestion of landfill waste, whereas, methanotrophic bacteria consume CH4 as it is transported through a landfill cover soil. Methanotrophs are thought to be ubiquitous in soils, but typically exist in large numbers at oxic/anoxic interfaces, close to anaerobic methane sources but exposed to oxygen required for metabolism. Accurate in-situ quantification of the sink strength of methanotrophs in landfill cover soils is needed for global carbon balances and for local emissions mitigation strategies. We measured in-situ CH4 concentrations at 30, 60, and 100 cm depth at 18 evenly spaced locations across a landfill cover soil. Furthermore, we performed Gas Push-Pull Tests (GPPTs) to estimate in-situ rates of methanotrophic activity in the cover soil. The GPPT is a gas-tracer test in which a gas mixture containing CH4, O2, and non-reactive tracer gases is injected (pushed) into the soil followed by extraction (pull) from the same location. Quantification of CH4 oxidation rates is based upon comparison of the breakthrough curves of CH4 and tracer gases. We present the results of a series of GPPTs conducted at two locations in the cover soil to assess the feasibility and reproducibility of this technique to quantify methanotrophic activity. Additional GPPTs were performed with a methanotrophic inhibitor in the injection gas mixture to confirm the appropriate choice of tracers to quantify CH4 oxidation. Estimated CH4 oxidation rate constants indicate that the cover soil contains a highly active methanotrophic community.

  18. In situ, field-scale evaluation of surfactant-enhanced DNAPL recovery using a single-well, ``push-pull'' test

    Energy Technology Data Exchange (ETDEWEB)

    Istok, J.D.; Field, J.A.

    1999-10-01

    The overall goal of this project was to further develop the single-well, ``push-pull'' test method as a feasibility assessment and site-characterization tool for studying the fundamental fate and transport behavior of injected surfactants and their ability to solubilize and mobilize dense nonaqueous phase liquids (DNAPLs) in the subsurface. The specific objectives were to develop a modified push-pull test for use in identifying and quantifying the effects of sorption, precipitation, and biodegradation on the fate and transport of injected surfactants, use the developed test method to quantify the effects of these processes on the ability of injected surfactants to solubilize and mobilize residual phase trichloroethane (TCE), and demonstrate the utility of the developed test method for performing site characterization and feasibility studies for surfactant-enhanced DNAPL recovery systems in the field. The results from the intermediate-scale laboratory experiments conducted for this project indicate that the single-well, push-pull test method can provide quantitative information on the effectiveness of injected surfactants in enhancing DNAPL solubilization in natural aquifer sediments. Specifically, the results of this research demonstrate the ability of the single-well, push-pull test to characterize the behavior of multi-component surfactants in the presence of natural aquifer sediment under laboratory and in-situ field conditions.

  19. L4-L5 compression and anterior/posterior joint shear forces in cabin attendants during the initial push/pull actions of airplane meal carts

    DEFF Research Database (Denmark)

    Sandfeld, Jesper; Rosgaard, Christian; Jensen, Bente Rona

    2014-01-01

    The aim of the present study was to assess the acute low back load of cabin attendants during cart handling and to identify working situations which present the highest strain on the worker. In a setup, 17 cabin attendants (ten females and seven males) pushed, pulled and turned a 20kg standard me...

  20. Impact of the Anchoring Ligand on Electron Injection and Recombination Dynamics at the Interface of Novel Asymmetric Push-Pull Zinc Phthalocyanines and TiO2

    NARCIS (Netherlands)

    Sharma, Divya; Steen, Gerrit Willem; Korterik, Jeroen P.; Garcia-Iglesias, M.; Vazquez, P; Torres, T.; Herek, Jennifer Lynn; Huijser, Jannetje Maria

    2013-01-01

    Phthalocyanines are promising photosensitizers for dye-sensitized solar cells (DSSCs). A parameter that has been problematic for a long time involves electron injection (EI) into the TiO2. The development of push-pull phthalocyanines shows great potential to improve the ratio of EI to back electron

  1. Impact of the Anchoring Ligand on Electron Injection and Recombination Dynamics at the Interface of Novel Asymmetric Push-Pull Zinc Phthalocyanines and TiO2

    NARCIS (Netherlands)

    Sharma, D.; Steen, G.W.; Korterik, J.P.; Garcia-Iglesias, M.; Vazquez, P; Torres, T.; Herek, J.L.; Huijser, J.M.

    2013-01-01

    Phthalocyanines are promising photosensitizers for dye-sensitized solar cells (DSSCs). A parameter that has been problematic for a long time involves electron injection (EI) into the TiO2. The development of push-pull phthalocyanines shows great potential to improve the ratio of EI to back electron

  2. Regioselective Synthesis of a Stereodefined Heterocyclic Push-Pull Alkene (Super 1)H NMR Studies and Two-Dimensional TLC Illustrating Z/E Isomerization

    Science.gov (United States)

    Markovic, Rade; Baranac, Marija; Jovanovic, Vesna; Dzambaski, Zdravko

    2004-01-01

    The experiment describes the regioselective synthesis of a stereodefined push-pull alkene from inexpensive chemicals. Important concepts in organic chemistry, such as resonance theory and role of solvent polarity on formation of intra- and intermolecular hydrogen bonds, which affect the configuration of the double bond in predictable way are…

  3. Regioselective Synthesis of a Stereodefined Heterocyclic Push-Pull Alkene (Super 1)H NMR Studies and Two-Dimensional TLC Illustrating Z/E Isomerization

    Science.gov (United States)

    Markovic, Rade; Baranac, Marija; Jovanovic, Vesna; Dzambaski, Zdravko

    2004-01-01

    The experiment describes the regioselective synthesis of a stereodefined push-pull alkene from inexpensive chemicals. Important concepts in organic chemistry, such as resonance theory and role of solvent polarity on formation of intra- and intermolecular hydrogen bonds, which affect the configuration of the double bond in predictable way are…

  4. The strategic ''pull'' and operational ''push'' of total quality management in UK regional electricity service companies

    Energy Technology Data Exchange (ETDEWEB)

    McAdam, R.; McLean, J.; Henderson, J.

    2003-04-30

    The aim of this paper is to evaluate whether the UK regional electricity companies (RECs) has used total quality management (TQM) as a ''push'' or as a ''pull'' change methodology. ''Push'' is the operational improvement role of TQM; ''pull'' is the strategic or direction giving, improvement role of TQM. Following the onset of privatisation in 1990 there has been evidence of the RECs adopting TQM in both ''push'' and ''pull'' methodologies with varying degrees of success. An evaluation of the change processes involved will enable improved change models to be developed leading to increased business effectiveness in this 30 billion pounds sterling industry. Other possible benefits include the possible generalisations to other utilities such as water, roads, gas and telecoms. The research methodology includes a comparative case study analysis of five RECs, which have used TQM as their overarching approach to change. One of the cases is analysed to a more in-depth level based on the multiple case findings. The findings indicate that the ''push-pull'' analysis enables the full range of TQM activities to be evaluated in the RECs studied. Overall, there is a need to have a balanced portfolio of operational or ''push''-based TQM activity that is driven by strategic or ''pull'' based TQM planning and activity. (author)

  5. International migration of health professionals and the marketization and privatization of health education in India: from push-pull to global political economy.

    Science.gov (United States)

    Walton-Roberts, Margaret

    2015-01-01

    Health worker migration theories have tended to focus on labour market conditions as principal push or pull factors. The role of education systems in producing internationally oriented health workers has been less explored. In place of the traditional conceptual approaches to understanding health worker, especially nurse, migration, I advocate global political economy (GPE) as a perspective that can highlight how educational investment and global migration tendencies are increasing interlinked. The Indian case illustrates the globally oriented nature of health care training, and informs a broader understanding of both the process of health worker migration, and how it reflects wider marketization tendencies evident in India's education and health systems. The Indian case also demonstrates how the global orientation of education systems in source regions is increasingly central to comprehending the place of health workers in the global and Asian rise in migration. The paper concludes that Indian corporate health care training systems are increasingly aligned with the production of professionals orientated to globally integrated health human resource labour markets, and our conceptual analysis of such processes must effectively reflect these tendencies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Photoinduced intramolecular charge transfer in push-pull polyenes: effects of solvation, electron-donor group, and polyenic chain length.

    Science.gov (United States)

    Akemann, Walther; Laage, Damien; Plaza, Pascal; Martin, Monique M; Blanchard-Desce, Mireille

    2008-01-17

    Subpicosecond absorption spectroscopy is used to characterize the primary photoinduced processes in a class of push-pull polyenes bearing a julolidine end group as the electron donor and a diethylthiobarbituric acid end group as the electron acceptor. The excited-state decay time and relaxation pathway have been studied for four polyenes of increasing chain length (n = 2-5 double bonds) in aprotic solvents of different solvation time, polarity, and viscosity. Intramolecular charge transfer (ICT) leading to a transient state of cyanine-like structure (fully conjugated with no bond length alternation) is observed in all polar solvents at a solvent dependent rate, but the reaction is not observed in cyclohexane, a nonpolar solvent. In polar solvents, the reaction time increases with the average solvation time but remains slightly larger, except in the viscous solvent triacetin. These facts are interpreted as an indication that both solvent reorganization and internal restructuring are involved in the ICT-state formation. The observed photodynamics resemble those we previously found for another class of polyenes bearing a dibutylaniline group as the donor, including a similar charge-transfer rate in spite of the larger electron donor character of the julolidine group. This observation brings further support to the proposal that an intramolecular coordinate is involved in the charge-transfer reaction, possibly a torsional motion of the donor end group. On the other hand, relaxation of the ICT state leads to cis-trans isomerization or crossing to the triplet state, depending on the length of the polyenic chain. In dioxane, tetrahydrofuran, and triacetin, the ICT state of the shorter chains (n = 2, 3) relaxes to the isomer with a viscosity-dependent rate, while that of the longer ones (n = 4, 5) leads to the triplet state with a viscosity-independent rate, as expected. In acetonitrile, the ICT-state lifetime is generally much shorter. A change from photoisomerization to

  7. Effects of Bulky Substituents of Push-Pull Porphyrins on Photovoltaic Properties of Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Higashino, Tomohiro; Kawamoto, Kyosuke; Sugiura, Kenichi; Fujimori, Yamato; Tsuji, Yukihiro; Kurotobi, Kei; Ito, Seigo; Imahori, Hiroshi

    2016-06-22

    To evaluate the effects of substituent bulkiness around a porphyrin core on the photovoltaic properties of porphyrin-sensitized solar cells, long alkoxy groups were introduced at the meso-phenyl group (ZnPBAT-o-C8) and the anchoring group (ZnPBAT-o-C8Cn, n = 4, 8) of an asymmetrically substituted push-pull porphyrin with double electron-donating diarylamino groups and a single electron-withdrawing carboxyphenylethynyl anchoring group. The spectroscopic and electrochemical properties of ZnPBAT-o-C8 and ZnPBAT-o-C8Cn were found to be superior to those of a push-pull porphyrin reference (YD2-o-C8), demonstrating their excellent light-harvesting and redox properties for dye-sensitized solar cells. A power conversion efficiency (η) of the ZnPBAT-o-C8-sensitized solar cell (η = 9.1%) is higher than that of the YD2-o-C8-sensitized solar cell (η = 8.6%) using iodine-based electrolyte due to the enhanced light-harvesting ability of ZnPBAT-o-C8. In contrast, the solar cells based on ZnPBAT-o-C8Cn, possessing the additional alkoxy chains in the anchoring group, revealed the lower η values of 7.3% (n = 4) and 7.0% (n = 8). Although ZnPBAT-o-C8Cn exhibited higher resistance at the TiO2-dye-electrolyte interface by virtue of the extra alkoxy chains, the reduced amount of the porphyrins on TiO2 by excessive addition of coadsorbent chenodeoxycholic acid (CDCA) for mitigating the aggregation on TiO2 resulted in the low η values. Meanwhile, the ZnPBAT-o-C8-sensitized solar cell showed the lower η value of 8.1% than the YD2-o-C8-sensitized solar cell (η = 9.8%) using cobalt-based electrolyte. The smaller η value of the ZnPBAT-o-C8-sensitized solar cell may be attributed to the insufficient blocking effect of the bulky substituents of ZnPBAT-o-C8 under the cobalt-based electrolyte conditions. Overall, the alkoxy chain length and substitution position around the porphyrin core are important factors to affect the cell performance.

  8. Use of gas push-pull tests for the measurement of methane oxidation in different landfill cover soils.

    Science.gov (United States)

    Streese-Kleeberg, Jan; Rachor, Ingke; Gebert, Julia; Stegmann, Rainer

    2011-05-01

    In order to optimise methane oxidation in landfill cover soils, it is important to be able to accurately quantify the amount of methane oxidised. This research considers the gas push-pull test (GPPT) as a possible method to quantify oxidation rates in situ. During a GPPT, a gas mixture consisting of one or more reactive gases (e.g., CH(4), O(2)) and one or more conservative tracers (e.g., argon), is injected into the soil. Following this, the mixture of injected gas and soil air is extracted from the same location and periodically sampled. The kinetic parameters for the biological oxidation taking place in the soil can be derived from the differences in the breakthrough curves. The original method of Urmann et al. (2005) was optimised for application in landfill cover soils and modified to reduce the analytical effort required. Optimised parameters included the flow rate during the injection phase and the duration of the experiment. 50 GPPTs have been conducted at different landfills in Germany during different seasons. Generally, methane oxidation rates ranged between 0 and 150 g m(soil air)(-3)h(-1). At one location, rates up to 440 g m(soil air)(-3)h(-1) were measured under particularly favourable conditions. The method is simple in operation and does not require expensive equipment besides standard laboratory gas chromatographs.

  9. Dissolved gas dynamics in wetland soils: Root-mediated gas transfer kinetics determined via push-pull tracer tests

    Science.gov (United States)

    Reid, Matthew C.; Pal, David S.; Jaffé, Peter R.

    2015-09-01

    Gas transfer processes are fundamental to the biogeochemical and water quality functions of wetlands, yet there is limited knowledge of the rates and pathways of soil-atmosphere exchange for gases other than oxygen and methane (CH4). In this study, we use a novel push-pull technique with sulfur hexafluoride (SF6) and helium (He) as dissolved gas tracers to quantify the kinetics of root-mediated gas transfer, which is a critical efflux pathway for gases from wetland soils. This tracer approach disentangles the effects of physical transport from simultaneous reaction in saturated, vegetated wetland soils. We measured significant seasonal variation in first-order gas exchange rate constants, with smaller spatial variations between different soil depths and vegetation zones in a New Jersey tidal marsh. Gas transfer rates for most biogeochemical trace gases are expected to be bracketed by the rate constants for SF6 and He, which ranged from ˜10-2 to 2 × 10-1 h-1 at our site. A modified Damköhler number analysis is used to evaluate the balance between biochemical reaction and root-driven gas exchange in governing the fate of environmental trace gases in rooted, anaerobic soils. This approach confirmed the importance of plant gas transport for CH4, and showed that root-driven transport may affect nitrous oxide (N2O) balances in settings where N2O reduction rates are slow.

  10. A revisit to self-excited push pull vacuum tube radio frequency oscillator for ion sources and power measurements.

    Science.gov (United States)

    Hlondo, L R; Lalremruata, B; Punte, L R M; Rebecca, L; Lalnunthari, J; Thanga, H H

    2016-04-01

    Self-excited push-pull vacuum tube oscillator is one of the most commonly used oscillators in radio frequency (RF)-ion plasma sources for generation of ions using radio frequency. However, in spite of its fundamental role in the process of plasma formation, the working and operational characteristics are the most frequently skip part in the descriptions of RF ion sources in literatures. A more detailed treatment is given in the present work on the RF oscillator alone using twin beam power tetrodes 829B and GI30. The circuit operates at 102 MHz, and the oscillation conditions, stability in frequency, and RF output power are studied and analyzed. A modified form of photometric method and RF peak voltage detection method are employed to study the variation of the oscillator output power with plate voltage. The power curves obtained from these measurements are quadratic in nature and increase with increase in plate voltage. However, the RF output power as measured by photometric methods is always less than the value calculated from peak voltage measurements. This difference is due to the fact that the filament coil of the ordinary light bulb used as load/detector in photometric method is not a perfect inductor. The effect of inductive reactance on power transfer to load was further investigated and a technique is developed to estimate the amount of power correction needed in the photometric measurement result.

  11. [Development of glipizide push-pull osmotic pump controlled release tablets by using expert system and artificial neural network].

    Science.gov (United States)

    Zhang, Zhi-Hong; Wang, Yue; Wu, Wen-Fang; Zhao, Xi; Sun, Xiao-Cui; Wang, Huan-Qing

    2012-12-01

    The purpose of this study is to develop glipizide push-pull osmotic pump (PPOP) tablets by using a formulation design expert system and an artificial neural network (ANN). Firstly, the expert system for the formulation design of osmotic pump of poor water-soluble drug was employed to design the formulation of glipizide PPOP, taking the dissolution test results of Glucotrol XL as the goal. Then glipizide PPOP was prepared according to the designed formulations and the in vitro dissolution was carried out. And in vivo evaluation was carried out between the samples which were similar to Glucotrol XL and the Glucotrol XL in Beagle dogs. The range of the factors of formulation and procedure, which could influence the drug release, was optimized using artificial neural network. Finally, the design space was found. It was found that the target formulation which was similar to Glucotrol XL in dissolution test could be obtained in a short period by using the expert system. The samples which were similar to Glucotrol XL were bio-equivalent to the Glucotrol XL in Beagle dogs. The design space of the key parameter coating weight gain was 9.5%-12.0%. It could be concluded that a well controlled product of glipizide PPOP was developed since the dissolution test standard of our product was more strict than that of Glucotrol XL.

  12. Azo polymers with electronical push and pull structures prepared via RAFT polymerization and its photoinduced birefringence behavior

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Two methacrylate monomers containing azo and electronical push and pull structure, e.g. 2-Methyl-acrylic-acid-2-{[4-(4-cyano-phenylazo-3-methyl-phenyl]-ethyl-amino-ethyl ester (MACP with cyano substituted and 2-Methylacrylic-acid-2-{ethyl-[4-(4-methoxy-phenylazo-3-methyl-phenyl]-amino}-ethyl ester (MAMP with methoxy substituted, were synthesized and polymerized using 2-cyanoprop-2-yl dithiobenzoate (CPDB as chain transfer agent and 2,2'-azobisisobutyronitrile (AIBN as initiator. The results showed that the polymerization displayed characteristics of ‘living’/controlled free radical polymerization. Thus, the obtained polymers, polyMACP (pMACP and polyMAMP (pMAMP, had controlled molecular weights and narrow molecular weights distribution. The chain extension experiments of pMACP and pMAMP using styrene as the second monomer were successfully carried out. The photo-induced trans-cis-trans isomerization kinetic of pMACP and pMAMP in chloroform solution were described. Marked differences in rate for the trans-cis and cis-trans isomerization of pMACP and pMAMP were observed in chloroform solution due to the different electronic effects in these two polymers. Photoinduced birefringence and surface relief grating (SRG of the pMACP and pMAMP were investigated in thin film state.

  13. Dual-functional Memory and Threshold Resistive Switching Based on the Push-Pull Mechanism of Oxygen Ions

    KAUST Repository

    Huang, Yi-Jen

    2016-04-07

    The combination of nonvolatile memory switching and volatile threshold switching functions of transition metal oxides in crossbar memory arrays is of great potential for replacing charge-based flash memory in very-large-scale integration. Here, we show that the resistive switching material structure, (amorphous TiOx)/(Ag nanoparticles)/(polycrystalline TiOx), fabricated on the textured-FTO substrate with ITO as the top electrode exhibits both the memory switching and threshold switching functions. When the device is used for resistive switching, it is forming-free for resistive memory applications with low operation voltage (<±1 V) and self-compliance to current up to 50 μA. When it is used for threshold switching, the low threshold current is beneficial for improving the device selectivity. The variation of oxygen distribution measured by energy dispersive X-ray spectroscopy and scanning transmission electron microscopy indicates the formation or rupture of conducting filaments in the device at different resistance states. It is therefore suggested that the push and pull actions of oxygen ions in the amorphous TiOx and polycrystalline TiOx films during the voltage sweep account for the memory switching and threshold switching properties in the device.

  14. Dual-functional Memory and Threshold Resistive Switching Based on the Push-Pull Mechanism of Oxygen Ions

    Science.gov (United States)

    Huang, Yi-Jen; Chao, Shih-Chun; Lien, Der-Hsien; Wen, Cheng-Yen; He-Hau, Jr.; Lee, Si-Chen

    2016-04-01

    The combination of nonvolatile memory switching and volatile threshold switching functions of transition metal oxides in crossbar memory arrays is of great potential for replacing charge-based flash memory in very-large-scale integration. Here, we show that the resistive switching material structure, (amorphous TiOx)/(Ag nanoparticles)/(polycrystalline TiOx), fabricated on the textured-FTO substrate with ITO as the top electrode exhibits both the memory switching and threshold switching functions. When the device is used for resistive switching, it is forming-free for resistive memory applications with low operation voltage (compliance to current up to 50 μA. When it is used for threshold switching, the low threshold current is beneficial for improving the device selectivity. The variation of oxygen distribution measured by energy dispersive X-ray spectroscopy and scanning transmission electron microscopy indicates the formation or rupture of conducting filaments in the device at different resistance states. It is therefore suggested that the push and pull actions of oxygen ions in the amorphous TiOx and polycrystalline TiOx films during the voltage sweep account for the memory switching and threshold switching properties in the device.

  15. Novel hybrid organic-inorganic sol-gel materials based on highly efficient heterocyclic push-pull chromophores

    Science.gov (United States)

    Abbotto, Alessandro; Bozio, Renato; Brusatin, Giovanna; Facchetti, Antonio; Guglielmi, Massimo; Innocenzi, Plinio; Meneghetti, Moreno; Pagani, Giorgio A.; Signorini, Raffaella

    1999-10-01

    We report the synthesis of sol-gel materials based on highly efficient heterocycle-based push-pull chromophores showing second- and third-order nonlinear optical activity. We show the proper functionalization of the best performing chromophores and their incorporation into a hybrid organic- inorganic sol-gel matrix. Different types of functionalization of the active molecule have been considered, including hydroxyl and alkoxysilyl end-groups. The functionalization strategy responded to different criteria such as stability and synthetic availability of the final molecular precursors, their solubility, and the used synthetic approach to the sol-gel material. The synthesis of the sol-gel materials has been tuned in order to preserve molecular properties and control important factors such as final concentration of the active dye in the matrix. Both acid- and base-catalyzed sol-gel synthesis has been taken into account. 3-Glycidoxypropyltrimethoxysilane and 3- aminopropyltriethoxysilane have been used as the organically modified alkoxides to prepare the hybrid organic-inorganic matrix. Characterization of the spectroscopic properties of the sol-gel materials is presented.

  16. Intermediate-sensor assisted push-pull strategy and its application in heterologous deoxyviolacein production in Escherichia coli.

    Science.gov (United States)

    Fang, Mingyue; Wang, Tianmin; Zhang, Chong; Bai, Jili; Zheng, Xiang; Zhao, Xuejin; Lou, Chunbo; Xing, Xin-Hui

    2016-01-01

    Because high-throughput screening tools are typically unavailable when using the pathway-engineering approach, we developed a new strategy, named intermediate sensor-assisted push-pull strategy, which enables sequential pathway optimization by incorporating a biosensor targeting a key pathway intermediate. As proof of concept, we constructed an L-Trp biosensor and used it to optimize the deoxyviolacein biosynthetic pathway, which we divided into two modules with L-Trp being the product of the upstream and the substrate of the downstream module for deoxyviolacein synthesis. Using the biosensor and fluorescence-activated cell sorting, the activities of the two modules were sequentially and independently optimized in Escherichia coli to achieve the desired phenotypes. By this means, we increased the deoxyviolacein titer 4.4-fold (1.92 g/L), which represents the greatest deoxyviolacein production reported. This work suggests that a biosynthetic pathway can be enhanced to produce a value-added secondary metabolite(s) without available end-product screening method by using a central metabolic junction molecule biosensor(s).

  17. Vibrational fingerprint of the structural tuning in push-pull organic chromophores with quinoid or proaromatic spacers.

    Science.gov (United States)

    Casado, Juan; Moreno Oliva, María; Ruiz Delgado, M Carmen; López Navarrete, Juan T; Sánchez, Luis; Martín, Nazario; Andreu, Raquel; Carrasquer, Laura; Garín, Javier; Orduna, Jesús

    2007-02-21

    The Raman spectra of a series of push-pull molecules containing probenzenoid or quinoid spacers which are substituted with 1,3-dithiol-2-ylidene as donor and dicyano-methylene or barbituric acid as acceptors have been analyzed. The experimental spectra have been assigned and interpreted according to density functional theory calculations. Correlations between the Raman spectra of the isolated spacers and of the substituted molecules have been done. Raman bands in the 1620-1560 cm-1 interval provide vibrational markers of the quinoidaromatic structural evolution. This finding is supported by a careful inspection of geometrical parameters, namely, bond length alteration data and particular bond distances. As a result, the peak positions and relative intensities of these Raman features can be used to evaluate the benzenoid character of the spacer as a function of the donor/acceptor substitution pattern. This paper shows that Raman spectroscopy is a powerful spectroscopic tool for the analysis of the conjugational properties (i.e., intramolecular donor-->acceptor charge transfer) of new organic materials.

  18. In vitro and in vivo evaluation of a novel push-pull osmotic pump with orifices on both side surfaces.

    Science.gov (United States)

    Li, Wei; Du, Gani; Yang, Xinggang; Zhang, Zhihong; Nie, Shufang; Peng, Bo; Pan, Weisan

    2008-12-01

    A novel push-pull osmotic pump (PPOP) was developed for delivery of water-insoluble drug gliclazide. Compared to conventional PPOP, which only had orifice(s) on the side of the drug layer, the novel PPOP had orifices of the same diameter on both side surfaces. The in vitro drug-release behavior of both novel PPOP and conventional PPOP were studied and compared; it was found that the drug-release rate of both kinds of PPOP could be influenced by coating level and core hardness whereas orifice size did not have much influence on it, and the study also showed that none of the former factors could influence the similarity of the drug-release profiles of the two kinds of PPOP. Mechanism of drug release from novel PPOP was illustrated using Poiseuille's law of lamina flow, and it was found that under regular formulation, the dissolution profiles of the two kinds of PPOP were similar. In vivo study also showed that the concentration-time profiles of gliclazide in plasma of the two PPOP were comparable and both of them had good in vitro-in vivo correlation. By simply drilled on both side surfaces, the novel PPOP did not need side identification when drilled, so it was more suitable for industrial manufacture than the conventional ones.

  19. Bright and photostable push-pull pyrene dye visualizes lipid order variation between plasma and intracellular membranes

    Science.gov (United States)

    Niko, Yosuke; Didier, Pascal; Mely, Yves; Konishi, Gen-Ichi; Klymchenko, Andrey S.

    2016-01-01

    Imaging lipid organization in cell membranes requires advanced fluorescent probes. Here, we show that a recently synthesized push-pull pyrene (PA), similarly to popular probe Laurdan, changes the emission maximum as a function of lipid order, but outperforms it by spectroscopic properties. In addition to red-shifted absorption compatible with common 405 nm diode laser, PA shows higher brightness and much higher photostability than Laurdan in apolar membrane environments. Moreover, PA is compatible with two-photon excitation at wavelengths >800 nm, which was successfully used for ratiometric imaging of coexisting liquid ordered and disordered phases in giant unilamellar vesicles. Fluorescence confocal microscopy in Hela cells revealed that PA efficiently stains the plasma membrane and the intracellular membranes at >20-fold lower concentrations, as compared to Laurdan. Finally, ratiometric imaging using PA reveals variation of lipid order within different cellular compartments: plasma membranes are close to liquid ordered phase of model membranes composed of sphingomyelin and cholesterol, while intracellular membranes are much less ordered, matching well membranes composed of unsaturated phospholipids without cholesterol. These differences in the lipid order were confirmed by fluorescence lifetime imaging (FLIM) at the blue edge of PA emission band. PA probe constitutes thus a new powerful tool for biomembrane research.

  20. Analysis of alternative push-pull-test-designs for determining in-situ trapping of CO2

    Science.gov (United States)

    Rasmusson, M.; Rasmusson, K.; Fagerlund, F.; Niemi, A.; Bensabat, J.; Shtivelman, V.

    2012-04-01

    Modeling results of different single-well push-pull (injection-withdrawal) test designs have been analyzed for their ability to determine residual and dissolution trapping of CO2 in-situ. The modeling aims to improve the design of a CO2 push-pull test that will be part of the field experiment conducted at the Heletz site, Israel, within the EU FP7 MUSTANG project. The injection will take place in a saline formation, where the target layer, an about 10 m thick sandstone layer composed of three layers, is located at a depth of 1600 m. Single-well experiments complement two-well injection-monitoring tests in that they offer a way of reducing heterogeneity effects on CO2 transport in comparison to two-well tests. The test scenarios simulated combine thermal, hydraulic and tracer tests in line with the work by Zhang et al (2011), where the test sequences have three main stages divided into (i) reference tests, (ii) creation of a zone of residual gas saturation and (iii) testing during residual gas saturation conditions. One of the main interests is to compare different ways of creating the residual zone, the two principal approaches being to push the mobile CO2 away by injecting CO2 saturated water, thus leaving the residual zone behind or by pumping the mobile CO2 back. Implications of the different designs on optimal use of tracers are also analyzed. Inverse modeling with the iTOUGH2/EOS17 and EOS7c simulators is used to analyze the ability of the competing test designs to accurately determine parameters of main interest during CO2 sequestration, in particular the residual gas saturation and dissolution. The inverse modeling approach uses results from e.g. sensitivity analysis and uncertainty propagation analysis to make design decisions leading to improvements in the test scenarios, choosing the optimum pumping and injection rates, heating effects, amount of CO2 used, tracer and method to create the zone of residual CO2 trapping, leading to a test design that will

  1. Hybrid electric vehicles and electrochemical storage systems — a technology push-pull couple

    Science.gov (United States)

    Gutmann, Günter

    In the advance of fuel cell electric vehicles (EV), hybrid electric vehicles (HEV) can contribute to reduced emissions and energy consumption of personal cars as a short term solution. Trade-offs reveal better emission control for series hybrid vehicles, while parallel hybrid vehicles with different drive trains may significantly reduce fuel consumption as well. At present, costs and marketing considerations favor parallel hybrid vehicles making use of small, high power batteries. With ultra high power density cells in development, exceeding 1 kW/kg, high power batteries can be provided by adapting a technology closely related to consumer cell production. Energy consumption and emissions may benefit from regenerative braking and smoothing of the internal combustion engine (ICE) response as well, with limited additional battery weight. High power supercapacitors may assist the achievement of this goal. Problems to be solved in practice comprise battery management to assure equilibration of individual cell state-of-charge for long battery life without maintenance, and efficient strategies for low energy consumption.

  2. Optimal Design of a Push-Pull-Forward Half-Bridge (PPFHB) Bidirectional DC–DC Converter With Variable Input Voltage

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

    2012-01-01

    This paper presents a low-cost bidirectional isolated dc–dc converte, derived from dual-active-bridge converter for the power sources with variable output voltage like supercapacitors. The proposed converter consists of push-pull-forward circuit half-bridge circuit (PPFHB) and a high-frequency tr...... by digital signal processor for comparison purpose. Detailed test results verify the theoretical analysis and demonstrate the validity of optimization design method....

  3. Inference of Fractured Rock Transport Properties by Joint Inversion of Push-Pull and Single-Hole Ground Penetrating Radar Data

    Science.gov (United States)

    Shakas, A.; Linde, N.; Bour, O.; Le Borgne, T.

    2015-12-01

    Flow and transport characterization of fractured rock formations is very challenging and important for a multitude of applications that include groundwater extraction, nuclear waste storage and geothermal energy production. One popular hydrogeological method to study fractured rock is a push-pull test, in which injection and retrieval of a tracer is made at the same depth interval in a borehole. In theory, push-pull tests are not sensitive to changes in the heterogeneity of the tracer flow path since the retrieval at the injection location minimizes advective effects and makes the test more sensitive to time-dependent transport processes. This assumption is limiting in the presence of a natural hydraulic gradient or if non-neutrally buoyant tracers are used, but these limitations can be reduced by monitoring push-pull tests with ground penetrating radar (GPR). We present a methodology for combined modeling and inversion of a series of push-pull tests that we monitored with the single hole ground penetrating radar (GPR) method. For the GPR modeling we use a newly developed approach to simulate the GPR response in fractured rock. We coupled the GPR model to a flow-and-transport simulator that we use to define the electrical properties of the fracture filling. The combined model can cope with heterogeneous fractures of any orientation, aperture and size and allows for the effect of density driven flow (that is strong during the saline tracer tests). We use the combined simulator to create synthetic datasets for both the time-series of the GPR traces at different locations and the tracer breakthrough curves. Since the combined problem is highly non-linear and the inverse solution is ill-posed, we use stochastic inversion techniques to obtain probabilistic estimates of the parameters of interest (fracture length, orientation and aperture distribution) and assess the use of different measures to compare the simulated and experimental data.

  4. Development and characterization of "push-pull" sampling device with fast reaction quenching coupled to high-performance liquid chromatography for pharmaceutical process analytical technologies.

    Science.gov (United States)

    Chisolm, Claire N; Evans, Charles R; Jennings, Colin; Black, Will A; Antosz, Frederick J; Qiang, Yangqiao; Diaz, Angel R; Kennedy, Robert T

    2010-11-26

    A push-pull sampling system interfaced on-line to high-performance liquid chromatography (HPLC) was developed for micro-volume real-time monitoring of reaction mixtures. The device consists of concentric tubes wherein sample was continuously withdrawn through the outer tube and reaction quenchant continuously delivered through a recessed inner tube. The device allowed sampling rates of 0.1-6.0 μL/min from a reaction vessel and stopped the reaction by passive mixing with quenchant to preserve the conditions observed in the reaction vessel. A finite element model of the system showed that reaction mixtures could be completely mixed with quenchant within 4.3s at a flow rate of 1.0 μL/min. The model also showed that an offset distance of 1mm between the push capillary and sample capillary tips is sufficient to avoid leakage of quenchant/diluent into the bulk sample for push flow rates up to 95% of the pull flow rate. The maximum relative push flow rate was determined to be 90% of the pull flow rate experimentally. Delay between sampling and delivery to the HPLC was from 111±3s to 317±9s for pull flow rates from 1.0 to 3.0 μL/min in agreement with expected delays based on tubing volume. Response times were from 27±1s to 52±6s over the same flow rate range. The sampler was tested to determine the effects of sample viscosity. The sampler was also used to demonstrate periodic sampling capabilities. As a test of the system, it was used to monitor the base-catalyzed hydrolysis of aspirin for 1.5h, demonstrating its utility for monitoring an ongoing reaction.

  5. Electrostatics of cell membrane recognition: structure and activity of neutral and cationic rigid push-pull rods in isoelectric, anionic, and polarized lipid bilayer membranes.

    Science.gov (United States)

    Sakai, N; Gerard, D; Matile, S

    2001-03-21

    Design, synthesis, and structural and functional studies of rigid-rod ionophores of different axial electrostatic asymmetry are reported. The employed design strategy emphasized presence of (a) a rigid scaffold to minimize the conformational complexity, (b) a unimolecular ion-conducting pathway to minimize the suprastructural complexity and monitor the function, (c) an extended fluorophore to monitor structure, (d) variable axial rod dipole, and (e) variable terminal charges to create axial asymmetry. Studies in isoelectric, anionic, and polarized bilayer membranes confirmed a general increase in activity of uncharged rigid push-pull rods in polarized bilayers. The similarly increased activity of cationic rigid push-pull rods with an electrostatic asymmetry comparable to that of alpha-helical bee toxin melittin (positive charge near negative axial dipole terminus) is shown by fluorescence-depth quenching experiments to originate from the stabilization of transmembrane rod orientation by the membrane potential. The reduced activity of rigid push-pull rods having an electrostatic asymmetry comparable to that in alpha-helical natural antibiotics (a positive charge near the positive axial dipole terminus) is shown by structural studies to originate from rod "ejection" by membrane potentials comparable to that found in mammalian plasma membranes. This structural evidence for cell membrane recognition by asymmetric rods is unprecedented and of possible practical importance with regard to antibiotic resistance.

  6. Real-time density matrix renormalization group dynamics of spin and charge transport in push-pull polyenes and related systems

    Science.gov (United States)

    Dutta, Tirthankar; Ramasesha, S.

    2012-01-01

    In this paper we investigate the effect of terminal substituents on the dynamics of spin and charge transport in donor-acceptor substituted polyenes [D-(CH)x-A] chains, also known as push-pull polyenes. We employ a long-range correlated model Hamiltonian for the D-(CH)x-A system, and time-dependent density matrix renormalization group technique for time propagating the wave packet obtained by injecting a hole at a terminal site, in the ground state of the system. Our studies reveal that the end groups do not affect spin and charge velocities in any significant way, but change the amount of charge transported. We have compared these push-pull systems with donor-acceptor substituted polymethine imine (PMI), D-(CHN)x-A, systems in which besides electron affinities, the nature of pz orbitals in conjugation also alternate from site to site. We note that spin and charge dynamics in the PMIs are very different from that observed in the case of push-pull polyenes, and within the time scale of our studies, transport of spin and charge leads to the formation of a “quasi-static” state.

  7. Push-pull-thinking

    DEFF Research Database (Denmark)

    Kolodovski, A.

    2006-01-01

    Scientific innovation takes two distinct paths. Sometimes, companies ask researchers to develop a solution for a specific business problem. This is a demand-driven, “PULL” method. In other cases, scientists develop a technology with new valuablecapabilities, and then search for commercial applica...

  8. Deep groundwater flow systems and their characterization in single-well settings by ''push-pull'' tracer tests

    Energy Technology Data Exchange (ETDEWEB)

    Hebig-Schubert, Klaus

    2014-11-21

    This thesis demonstrates the growing importance of deep groundwater research and the increasing demand for the development of suitable single-well test methods. At the forefront of the research on groundwater in the deep underground, radioactive waste disposal in deep geological repositories, CO{sub 2} storage, geothermal energy supply, and aquifer storage and recovery systems (ASR) are on the agenda. The developments of suitable methods for investigating these resources are a main target. Currently available methods show considerable limitations. Accordingly, comprehensive methods for the hydraulic and hydrochemical characterization of deeper aquifers with single-well access are needed. Therefore, the goal of this PhD thesis was to identify, test, and enhance potentially suitable single-well methods for characterization of groundwater flow and solute transport in such settings. For this, several Single-Well Injection-Withdrawal (''push-pull'') tracer tests were applied at the Hamasato field site (Horonobe, Japan) in a ∝100 m deep groundwater monitoring well. Aim was to characterize the impact of a dynamic saltwater-freshwater interface on a coastal aquifer. Based on the experiences of the first methodological test, a second field campaign was conducted. This campaign focused on a systematic evaluation of the push-pull tracer test method for the first time at all. The experiments focused on the investigation of the so-called ''chaser'' and its impact on the test results. The chaser is a specific part of many push-pull tracer tests setups. From these experiments, a specific test design for the investigation of the saltwater-freshwater interface in a single-well setting was developed. The application of this design on questions regarding different fluids within the same system, e.g. different mineralized fluids (saltwater-freshwater-interface, ASR) or temperatures (geothermal research), are promising future approaches for

  9. RESEARCH ON THE PROCESS OF THE PUSH-PULL PICKLING LINE WITH HIGH PRODUCTIVITY%高产能推拉式酸洗机组工艺路线研究

    Institute of Scientific and Technical Information of China (English)

    张军生

    2012-01-01

    从与传统推拉式酸洗机组的区别入手,介绍了推拉式酸洗机组实现高产能的工艺路线和主要设备配置。%This article introduced the process route and main equipments of push-pull pickling line with high productivity, comparing with the traditional push-pull pickling line.

  10. Low temperature-pressure batch experiments and field push-pull tests: Assessing potential effects of an unintended CO2 release from CCUS projects on groundwater chemistry

    Science.gov (United States)

    Mickler, P. J.; Yang, C.; Lu, J.; Reedy, R. C.; Scanlon, B. R.

    2012-12-01

    Carbon Capture Utilization and Storage projects (CCUS), where CO2 is captured at point sources such as power stations and compressed into a supercritical liquid for underground storage, has been proposed to reduce atmospheric CO2 and mitigate global climate change. Problems may arise from CO2 releases along discreet pathways such as abandoned wells and faults, upwards and into near surface groundwater. Migrating CO2 may inversely impact fresh water resources by increasing mineral solubility and dissolution rates and mobilizing harmful trace elements including As and Pb. This study addresses the impacts on fresh water resources through a combination of laboratory batch experiments, where aquifer sediment are reacted in their corresponding groundwater in 100% CO2 environments, and field push-pull tests where groundwater is equilibrated with 100% CO2, reacted in-situ in the groundwater system, and pulled out for analyses. Batch experiments were performed on aquifer material from carbonate dominated, mixed carbonate/silicalstic, and siliclastic dominated systems. A mixed silicalstic/carbonate system was chosen for the field based push-pull test. Batch experiment results suggest carbonate dissolution increased the concentration of Ca, Mg, Sr, Ba, Mn, U and HCO3- in groundwater. In systems with significant carbonate content, dissolution continued until carbonate saturation was achieved at approximately 1000 hr. Silicate dissolution increased the conc. of Si, K Ni and Co, but at much lower rates than carbonate dissolution. The elements As, Mo, V, Zn, Se and Cd generally show similar behavior where concentrations initially increase but soon drop to levels at or below the background concentrations (~48 hours). A Push-Pull test on one aquifer system produced similar geochemical behavior but observed reaction rates are higher in batch experiments relative to push-pull tests. Release of CO2 from CCUS sites into overlying aquifer systems may adversely impact groundwater quality

  11. Solvent effects on chemical exchange in a push-pull ethylene as studied by NMR and electronic structure calculations.

    Science.gov (United States)

    Ababneh-Khasawneh, Maysoon; Fortier-McGill, Blythe E; Occhionorelli, Marzia E; Bain, Alex D

    2011-07-07

    NMR measurements of chemical exchange in a push-pull ethylene, dissolved in a number of different solvents, are presented. These are complemented by high-level electronic structure calculations, using both gas-phase conditions and those which simulate solvents. The results show that it is essential to include entropy effects in order to understand the observed trends. For instance, the equilibrium state in this case represents the state with lowest Gibbs free energy, as it must, but not the lowest enthalpy. The particular molecule is methyl 3-dimethylamino-2-cyanocrotonate (MDACC). The geometry at the carbon-carbon double bond can be either E or Z with roughly equal populations at ambient temperature. We have measured the equilibrium constant and the rates for the exchange between these states in a number of solvents: methanol, chloroform, acetonitrile, toluene, dichloromethane, acetone, and tetrahydrofuran. Furthermore, the N,N-dimethylamino group attached to the double bond also shows restricted rotation, and this has been measured in both the E and Z conformations. The equilibrium constant and the three rotational barriers provide excellent probes of the solvent effects. Electronic structure calculations with a number of basis sets up to the 6-311++G(2df,2p) level, using both Hartree-Fock and density functional (B3LYP) methods were used to predict the E and Z ground states, and the three transition states. The calculations were done for an isolated molecule and also for solvent models representing toluene, acetone, and ethanol. The E conformation is more stable in solution, is the structure in the crystal, and is also the prediction for the gas phase from the calculations. However, the dependence of the equilibrium constant on temperature shows that the Z conformation actually has lower enthalpy. The stability of the E conformation in solution must be due to entropic effects. Similarly, the solvent effect on the E-Z barrier is primarily due to entropy. The

  12. Tuning the push-pull configuration for efficient second-order nonlinear optical properties in some chalcone derivatives.

    Science.gov (United States)

    Muhammad, Shabbir; Al-Sehemi, Abdullah G; Irfan, Ahmad; Chaudhry, Aijaz R

    2016-07-01

    Using the density functional theory methods, we effectively tune the second-order nonlinear optical (NLO) properties in some chalcone derivatives. Various unique push-pull configurations are used to efficiently enhance the intramolecular charge transfer process over the designed derivatives, which result in significantly larger amplitudes of the first hyperpolarizability as compared to their parent molecule. The ground state molecular geometries have been optimized using B3LYP/6-311G** level of theory. A variety of methods including B3LYP, CAM-B3LYP, PBE0, M06, BHandHLYP and MP2 are tested with 6-311G** basis set to calculate the first hyperpolarizability of parent system 1. The results of M06 are found closer to highly correlated MP2 method, which has been selected to calculate static and frequency dependent first hyperpolarizability amplitudes of all selected systems. At M06/6-311G** level of theory, the permanent electronic dipole moment (μtot), polarizability (α0) and static first hyperpolarizability (βtot) amplitudes for parent system 1 are found to be 5.139 Debye, 274a. u. and 24.22×10(-30)esu, respectively. These amplitudes have been significantly enhanced in designed derivatives 2 and 3. More importantly, the (βtot) amplitudes of systems 2 and 3 mount to 75.78×10(-30) and 128.51×10(-30)esu, respectively, which are about 3 times and 5 times larger than that of their parent system 1. Additionally, we have extended the structure-NLO property relationship to several newly synthesized chalcone derivatives. Interestingly, the amplitudes of dynamic frequency dependent hyperpolarizability μβω (SHG) are also significantly larger having values of 366.72×10(-48), 856.32×10(-48) and 1913.46×10(-48)esu for systems 1-3, respectively, at 1400nm of incident laser wavelength. The dispersion behavior over a wide range of change in wavelength has also been studied adopting a range of wavelength from 1907 to 544nm. Thus, the present work realizes the potential of

  13. Online health information, situational effects and health changes among e-patients in Israel: A 'push/pull' perspective.

    Science.gov (United States)

    Mano, Rita

    2015-12-01

    -care decisions (c) chronically ill are not likely to use online health information. E-patients' expectations from health-care institutional providers play a central role in initiating health changes. Access and use of online health information provide an alternative/additional channel for information when e-patients consider health changes and create a push/pull decision-making strain on both providers and recipients of health services. Health-care providers should address e-patients'concerns, mainly in cases of chronic illness concerns, and point to the boundaries of online health information. Traditional and novel sources of health information can increase health empowerment and better health care when communication channels between health providers and e-patients are comfortably verified in advance and agreed upon. © 2014 John Wiley & Sons Ltd.

  14. Comprehensive investigation of the excited-state dynamics of push-pull triphenylamine dyes as models for photonic applications.

    Science.gov (United States)

    Ishow, Eléna; Clavier, Gilles; Miomandre, Fabien; Rebarz, Mateusz; Buntinx, Guy; Poizat, Olivier

    2013-09-07

    A series of emitting push-pull triarylamine derivatives, models of their widely used homologues in photonics and organic electronics, was investigated by steady-state and time-resolved spectroscopy. Their structural originality stems from the sole change of the electron-withdrawing substituent X (-H: 1, -CN: 2, -NO2: 3, -CHC(CN)2: 4), giving rise to efficient emission tuning from blue to red upon increasing the X electron-withdrawing character. All compounds are highly fluorescent in alkanes. The more polar compounds 2-4 undergo considerable Stokes shift and emission quenching in polar solvents. Femtosecond transient absorption data allowed us to identify the nature of the emissive state which varies as a function of the compound and surrounding polarity. A long-lived ππ* excited state with weak charge transfer character was found for 1. This excited state evolves into a long-lived ICT state with red-shifted emission for 2 in polar solvents. For 3 and 4, the ICT state is directly populated in all solvents. Long-lived and emissive in n-hexane, it relaxes in toluene to a new ICT' conformation with stronger charge transfer character and enhanced Stokes shift. In more polar THF, ethanol, and nitrile solvents, ICT relaxes to a dark excited state ICT'' with viscosity-dependent kinetics (ICT'' state lifetime drops with increasing solvent polarity (150 ps for 3 in THF, 8.5 ps in butyronitrile, 1.9 ps in acetonitrile), denoting an efficient radiationless deactivation to the ground state (back charge transfer). This result reveals a very small S0-S1 energy gap at the relaxed ICT'' geometry, with a possible close-lying S0-S1 conical intersection, which suggests that the ICT → ICT'' process results from a structural change involving a large-amplitude molecular distortion. This fast structural change can account for the strong fluorescence quenching observed for 3 and 4 in polar solvents. Finally, the magnitude of intersystem crossing between the singlet and triplet excited

  15. Model-based analysis of push-pull experiments in deep aquifers to predict large-scale impacts of CSG product water reinjection

    Science.gov (United States)

    Prommer, H.; Rathi, B.; Morris, R.; Helm, L.; Siade, A. J.; Davis, J. A.

    2015-12-01

    Over the next two decades coal seam gas production in Australia will require the management of large quantities of production water. For some sites the most viable option is to treat the water to a high standard via reverse osmosis (RO) and to inject it into deep aquifers. The design and implementation of these field-scale injection schemes requires a thorough understanding of the anticipated water quality changes within the target aquifers. In this study we use reactive transport modeling to integrate the results of a multi-scale hydrogeological and geochemical characterization, and to analyze a series of short-term push-pull experiments with the aim to better understand and reliably accurately predict long-term water quality evolution and the risks for mobilizing geogenic arsenic. Sequential push-pull tests with varying injectant compositions were undertaken, with concentrations recorded during the recovery phase reaching levels of up to 180 ppb above the ambient concentrations observed prior to the push-pull experiments. The highest As concentrations were observed in conjunction with the injection of aerobic water, while de-oxygenation of the injectant lowered As concentrations significantly. The lowest As concentrations were observed when the injectant was de-oxygenated and acid-amended. The latter was underpinned by complementary laboratory As sorption experiments using sediments from the target aquifer at various pHs, which, consistent with literature, show a decrease in As sorption affinity under alkaline conditions. In the model-based analysis of the experimental data, model parameters for each conceptual model variant were estimated through an automatic calibration procedure using Particle Swarm Optimization (PSO) whereby bromide and temperature data were used to constrain flow, solute and heat transport parameters. A series of predictive model scenarios were performed to determine whether advanced manipulation of the injectant composition is required.

  16. pi-Delocalization in oligoalkynes induced by push-pull substituents and 1,3-conjugation: a combined (13)C NMR and computational study.

    Science.gov (United States)

    Kleinpeter, Erich; Koch, Andreas

    2009-10-08

    (13)C chemical shifts of the push-pull oligoalkynes Don-(C identical withC)(n)-Acc (n = 1-4; Don = morpholino; Acc = COMe, COOMe) were computed at the DFT (B3LYP/6-311+G(d,p) level of theory compared with the experimental delta values and the agreement employed as a measure of quality for the underlying structures. For the global minima structures, the occupation quotients of antibonding pi* and bonding pi orbitals (pi*(C[triple bond]C)/pi(C[triple bond]C)) and the bond lengths (d(C[triple bond]C)) of the various C[triple bond]C triple bonds were also computed and correlated to each other. The linear dependence obtained for the two parameters d(C identical withC) and pi*(C[triple bond]C)/pi(C[triple bond]C) quantifies changes in pi-delocalization induced by the push-pull effect of the substituents and 1,3-conjugation (1,3,5- and 1,3,5,7-, respectively) of the C identical withC bonds in the oligoalkynes studied. A critical comparison of the push-pull effect, attenuated with increasing n, and the conjugative stabilization of the oligoalkynes, increasing with n, as concluded from d(C identical withC) and pi*(C[triple bond]C)/pi(C[triple bond]C) of the oligoalkynes and the reference compounds Me-(C[triple bond]C)(n)-Me, Don-(C[triple bond]C)(n)-Me, and Me-(C[triple bond]C)(n)-Acc), respectively (Don = morpholino; Acc = COMe, COOMe), is affiliated.

  17. Introduction of an electron push-pull system yields a planar Red Kaede fluorescence protein chromophore analogue stabilized by a C = O… interaction

    Indian Academy of Sciences (India)

    Ashish Singh; Basanta Kumar Rajbongshi; Gurunath Ramanathan

    2015-05-01

    Crystal structures of four red kaede fluorescence protein chromophore analogues are reported here. Molecules I-III adopt a non-planar geometry stabilized by … stacking and hydrogen bonding. Introduction of an electron push-pull system induces molecule IV to be planar and a C = O… supramolecular interaction is observed as well. Strong electron withdrawing and donating groups also ensure formation of a higher order two and three dimensional supramolecular architecture through hydrogen bonds in molecules I and IV. All the analogues exhibit good photoluminescence properties and emit in the red region with excellent quantum yields.

  18. Relation between bond-length alternation and two-photon absorption of a push pull conjugated molecules: a quantum-chemical study

    Science.gov (United States)

    Bartkowiak, W.; Zaleśny, R.; Leszczynski, J.

    2003-02-01

    The results of the semiempirical study of the structure/property relationships for the two-photon absorption cross-section ( δ) of a series of prototypical π-conjugated push-pull molecules are presented. The calculations of δ for the first charge-transfer (CT) excited state were performed as a function of the bond length alternation (BLA). The molecular hyperpolarizabilities ( β and γ) were calculated using the finite-field (FF) method. The obtained data were analyzed based on the simple two-state models. A strong dependence of δ on the BLA parameter was noticed.

  19. Relation between bond-length alternation and two-photon absorption of a push-pull conjugated molecules: a quantum-chemical study

    Energy Technology Data Exchange (ETDEWEB)

    Bartkowiak, W.; Zalesny, R.; Leszczynski, J

    2003-02-01

    The results of the semiempirical study of the structure/property relationships for the two-photon absorption cross-section ({delta}) of a series of prototypical {pi}-conjugated push-pull molecules are presented. The calculations of {delta} for the first charge-transfer (CT) excited state were performed as a function of the bond length alternation (BLA). The molecular hyperpolarizabilities ({beta} and {gamma}) were calculated using the finite-field (FF) method. The obtained data were analyzed based on the simple two-state models. A strong dependence of {delta} on the BLA parameter was noticed.

  20. Density-functional theory (hyper)polarizabilities of push-pull pi-conjugated systems: treatment of exact exchange and role of correlation.

    Science.gov (United States)

    Bulat, Felipe A; Toro-Labbé, Alejandro; Champagne, Benoît; Kirtman, Bernard; Yang, Weitao

    2005-07-01

    The performance of the optimized effective potential procedure for exact exchange in calculating static electric-field response properties of push-pull pi-conjugated systems has been studied, with an emphasis on NO2-(CH=CH)n-NH2 chains. Good agreement with Hartree-Fock dipole moments and (hyper)polarizabilities is obtained; particularly noteworthy is the chain length dependence for beta/n. Thus, the problem that conventional density-functional theory functionals dramatically overestimate these properties is largely solved, although there remains a significant correlation contribution that cannot be accounted for with current correlation functionals.

  1. Comparison of the severity of injury of hippocampal neuron in rats induced by simulated push-pull maneuver at various degrees

    Institute of Scientific and Technical Information of China (English)

    Suhong Guo; Hui Zhang

    2006-01-01

    BACKGROUND: Push-pull effect is often caused during maneuver,and the changes of unconsciousness induced can affect or damage cerebral neurons at various degrees.OBJECTIVE: To observe the effect of simulated push-pull maneuver at various degrees on injury of hippocampal neurons in rats and analyze its phase effect.DESIGN: Randomized control study.SETTING: Physiological Department of Jilin Medical College.MATERIALS: A total of 40 healthy male Wistar rats, of clean grade, weighting 205-300 g, aged 3-4months, were randomly divided into control group (n=4) and three push-pull experimental groups, including ±2 Gz group (intensity: -2 Gz to +2 Gz, n=12), ±6 Gz group (-6 Gz to +6 Gz, n=12) and ±8 Gz group (-8 Gz to +8 Gz, n=12).METHODS:The experiment was completed in the Physiological Department of Jilin Military Medical College from March 2002 to May 2003. ① Rats in the experimental groups were put at the specially rolling arm of animal centrifugal machine. Then, they were pushed and pulled with ±2 Gz, ± 6 Gz and ±8 Gz, respectively. The jolt was 1 Gz/s. However, rats in control group were not treated with any ways. ② Stroke index and neurological evaluation were performed on rats in the experimental groups at 0.5,6 and 24 hours after push-pull. Stroke index was 25 points in total. The higher the scores were, the severer the cerebral injury was. Neurological evaluation was 10 points in total. The higher the scores were, the severer the nerve injury was. ③ Hippocampal tissue in brain of rats were selected to cut into sections at each time points, and form and distribution of neurons were observed in hippocampal areas with HE staining. Degrees of neuronal injury in hippocampal CA1 area were assayed after push-pull at various degrees with electron microscope.④ Measurement data were compared with t test.MAIN OUTCOME MEASURES:① Stroke index and neurological evaluation;② form and distribution of neurons in hippocampal areas; ③ degrees of neuronal injury in

  2. Design Points of Push-pull Pickling Process Section%推拉式酸洗机组工艺段的设计要点

    Institute of Scientific and Technical Information of China (English)

    程化; 郭振英

    2012-01-01

    介绍了推拉式酸洗机组的特点、相关参数,以及酸洗循环系统、清洗循环系统、废气处理系统的设计要点.%The characteristics and related parameters of push-pull pickling process were introduced . The design key points about pickling circulation system, washing circulation system and waste gas treating system were described in detail. At last, the suggestion of pickling line designing was conclusively given.

  3. Push/Pull和CONWIP/Pull生产控制模式对比分析%Comparison and Analysis of Production Control Methods of Push/Pull and CONWIP/Pull

    Institute of Scientific and Technical Information of China (English)

    林勇; 乐晓娟; 付秋芳

    2006-01-01

    针对制造企业如何有效地进行生产控制的问题,对Push/Pull、CONWIP、CONWIP/Pull生产控制模式作了详细介绍,对比分析了Push/Pull、CONWIP/Pull两种混合生产控制,对混合生产控制方法做出了研究展望.

  4. Enhanced isoprene biosynthesis in Saccharomyces cerevisiae by engineering of the native acetyl-CoA and mevalonic acid pathways with a push-pull-restrain strategy.

    Science.gov (United States)

    Lv, Xiaomei; Xie, Wenping; Lu, Wenqiang; Guo, Fei; Gu, Jiali; Yu, Hongwei; Ye, Lidan

    2014-09-30

    To explore the capacity of isoprene production in Saccharomyces cerevisiae, a rational push-pull-restrain strategy was proposed to engineer the mevalonic acid (MVA) and acetyl-CoA pathways. The strategy can be decomposed into the up-regulation of precursor supply in the acetyl-CoA module and the MVA pathway (push-strategy), increase of the isoprene branch flux (pull-strategy), and down-regulation of the competing pathway (restrain-strategy). Furthermore, to reduce the production cost arising from galactose addition and meanwhile maintain the high expression of Gal promoters, the galactose regulatory network was modulated by Gal80p deletion. Finally, the engineered strain YXM10-ispS-ispS could accumulate up to 37 mg/L isoprene (about 782-fold increase compared to the parental strain) under aerobic conditions with glycerol-sucrose as carbon source. In this way, a new potential platform for isoprene production was established via metabolic engineering of the yeast native pathways.

  5. Characteristics of silicon nitride deposited by VHF (162 MHz)-plasma enhanced chemical vapor deposition using a multi-tile push-pull plasma source

    Science.gov (United States)

    Kim, Ki Seok; Sirse, Nishant; Kim, Ki Hyun; Rogers Ellingboe, Albert; Kim, Kyong Nam; Yeom, Geun Young

    2016-10-01

    To prevent moisture and oxygen permeation into flexible organic electronic devices formed on substrates, the deposition of an inorganic diffusion barrier material such as SiN x is important for thin film encapsulation. In this study, by a very high frequency (162 MHz) plasma-enhanced chemical vapor deposition (VHF-PECVD) using a multi-tile push-pull plasma source, SiN x layers were deposited with a gas mixture of NH3/SiH4 with/without N2 and the characteristics of the plasma and the deposited SiN x film as the thin film barrier were investigated. Compared to a lower frequency (60 MHz) plasma, the VHF (162 MHz) multi-tile push-pull plasma showed a lower electron temperature, a higher vibrational temperature, and higher N2 dissociation for an N2 plasma. When a SiN x layer was deposited with a mixture of NH3/SiH4 with N2 at a low temperature of 100 °C, a stoichiometric amorphous Si3N4 layer with very low Si-H bonding could be deposited. The 300 nm thick SiN x film exhibited a low water vapor transmission rate of 1.18  ×  10-4 g (m2 · d)-1, in addition to an optical transmittance of higher than 90%.

  6. Optical properties of a visible push-pull chromophore covalently bound to carbohydrates: solution and gas-phase spectroscopy combined to theoretical investigations.

    Science.gov (United States)

    Enjalbert, Quentin; Racaud, Amandine; Lemoine, Jérôme; Redon, Sébastien; Ayhan, Mehmet Menaf; Andraud, Chantal; Chambert, Stéphane; Bretonnière, Yann; Loison, Claire; Antoine, Rodolphe; Dugourd, Philippe

    2012-01-19

    The use of visible absorbing and fluorescent tags for sensing and structural analysis of carbohydrates is a promising route in a variety of medical, diagnostic, and therapeutic contexts. Here we report an easy method for covalent attachment of nonfluorescent push-pull chromophores based on the 4-cyano-5-dicyanomethylene-2-oxo-3-pyrroline ring to carbohydrate moieties. The impact of sugar grafting on the optical properties of the push-pull chromophore in the gas phase and in solution was investigated by absorption and action spectroscopy and theoretical methods. The labeled sugars efficiently absorb photons in the visible range, as demonstrated by their intense photodissociation in a quadrupole ion trap. A strong blue shift (-70 nm) of the gas-phase photodissociation intensity maximum is observed upon sugar grafting, whereas no such effect is visible on the solution absorption spectra. Molecular dynamics simulations of labeled maltose in the gas phase describe strong interactions between the sulfonated chromophore and the carbohydrate, which lead to cyclic conformations. These are not observed in the simulations with explicit solvation. Time-dependent density functional theory (TD-DFT) calculations on model molecules permit us to attribute the observed shift to the formation of such cyclic conformations and to the displacement of the negative charge relative to the aromatic moiety of the chromophore.

  7. Push-Pull Type Oligo(N-annulated perylene)quinodimethanes: Chain Length and Solvent-Dependent Ground States and Physical Properties.

    Science.gov (United States)

    Zeng, Zebing; Lee, Sangsu; Son, Minjung; Fukuda, Kotaro; Burrezo, Paula Mayorga; Zhu, Xiaojian; Qi, Qingbiao; Li, Run-Wei; Navarrete, Juan T López; Ding, Jun; Casado, Juan; Nakano, Masayoshi; Kim, Dongho; Wu, Jishan

    2015-07-08

    Research on stable open-shell singlet diradicaloids recently became a hot topic because of their unique optical, electronic, and magnetic properties and promising applications in materials science. So far, most reported singlet diradicaloid molecules have a symmetric structure, while asymmetric diradicaloids with an additional contribution of a dipolar zwitterionic form to the ground state were rarely studied. In this Article, a series of new push-pull type oligo(N-annulated perylene)quinodimethanes were synthesized. Their chain length and solvent-dependent ground states and physical properties were systematically investigated by various experimental methods such as steady-state and transient absorption, two-photon absorption, X-ray crystallographic analysis, electron spin resonance, superconducting quantum interference device, Raman spectroscopy, and electrochemistry. It was found that with extension of the chain length, the diradical character increases while the contribution of the zwitterionic form to the ground state becomes smaller. Because of the intramolecular charge transfer character, the physical properties of this push-pull system showed solvent dependence. In addition, density functional theory calculations on the diradical character and Hirshfeld charge were conducted to understand the chain length and solvent dependence of both symmetric and asymmetric systems. Our studies provided a comprehensive understanding on the fundamental structure- and environment-property relationships in the new asymmetric diradicaloid systems.

  8. Raman and theoretical study of the solvent effects on the sizable intramolecular charge transfer in the push-pull 5-(dimethylamino)-5'-nitro-2,2'-bithiophene.

    Science.gov (United States)

    Ortí, Enrique; Viruela, Pedro M; Viruela, Rafael; Effenberger, Franz; Hernandez, Víctor; López Navarrete, Juan T

    2005-10-06

    In this paper, we analyze the degree of intramolecular charge transfer in a push-pull pi-conjugated system, 5-(dimethylamino)-5'-nitro-2,2'-bithiophene, from changes in frequencies and relative intensities of its strongest Raman scatterings in a bunch of solvents with different polarities. Density functional theory (DFT) was used as a support of the experimental study. Solvent effects on the molecular and electronic structures and on the vibrational properties were estimated by performing B3LYP/6-31G calculations within the framework of the polarized continuum model (PCM) developed by Tomasi. Calculations reveal that the molecule is highly polarized in the ground state and behaves as a very efficient photoinduced push-pull system. The polarization of the molecule strongly increases with solvent polarity and determines that the profile of the Raman spectra greatly changes from one solvent to another and in going to the solid. The strongest Raman scattering associated with the nu(sym)(NO(2)) stretching undergoes a downshift of 48 cm(-1) in passing from CCl(4) to the solid. DFT calculations provide a comprehensive interpretation of the evolution of the Raman spectra with solvent polarity.

  9. ZVS Three-transistor Push-pull DC/DC Converters%ZVS三管推挽直流变换器

    Institute of Scientific and Technical Information of China (English)

    袁义生; 伍群芳

    2012-01-01

    A three-transistor push-pull (TTPP) converter was proposed in this paper. An auxiliary transistor Q3 is inserted between the input power source and midpoint of two primary windings in a traditional push-pull converter. The driving signals ugsl and ugs2 of two main transistors are as inversely as that in traditional push-pull converter. Except for the dead time, the driving signal ugsi of the auxiliary transistor is equal to the inverse of ugsl &ugs2. By building the equivalent circuits and analytic equations, the operation theory and main switching waveforms of each operation modes were analyzed. Its main transistors can achieve ZVS under wide load range and turn off under half the current occurred in a traditional push-pull converter. The auxiliary transistor can realize ZVS under heavy load or with large leakage inductance. The rated voltage of the auxiliary transistor is half of that of the main transistors and is equal to Um. The soft-switching conditions were discussed. The PWM IC and driving circuit were presented. A 800W, 83.3kHz prototype was built. The experimental result verified the discussed theory correctly.%提出一种采用3个开关管的推挽式(three-transistors Push-Pull,TTPP)变换器,仅需要在传统推挽变换器的输入电源和变压器两个原边绕组中点间插入一个辅助开关管Q3.两个主管驱动信号μgs1和μgs2与传统推挽变换器中开关管的驱动信号相反;除去死区时间,辅管驱动信号μgs3是两个主管驱动信号μgs1和μgs2的与非关系.用等效电路的方法结合解析方程,分析电路各个工作模态的工作原理和主要开关波形.指出主管可在宽负载范围下实现零电压开通(zero voltage switching,zvS),且主管关断电流是传统推挽电路中的一半值.辅管在大负载或加大漏感情况下可以实现ZVS开通,辅管的额定电压是主管的一半,等于输入电压.讨论软开关的实现问题.提出控制芯片及其驱动电

  10. International Mobility of Undergraduate and Graduate Students in Science, Technology, Engineering, and Mathematics: Push and Pull Factors

    Science.gov (United States)

    Chien, Chiao-Ling

    2013-01-01

    This study examines factors that contribute to the cross-border movement of international students in science, technology, engineering, and mathematics (STEM) fields. It analyzes characteristics of host countries (pull factors) associated with international students' arrival for education in STEM fields, as well as characteristics of home…

  11. 移动数据库中数据访问的自适应PUSH+PULL算法%Adaptive PUSH+PULL algorithms of data access in mobile database

    Institute of Scientific and Technical Information of China (English)

    胡虚怀

    2006-01-01

    在移动计算机环境中,数据广播只适应于对具有公共访问兴趣的热点数据的访问,而传统的联机请求方式则可以访问任何服务器数据.因此,为了使移动数据库支持一般性的数据应用,提出了一种将数据广播方式(称作"推",即PUSH)和传统联机请求方式(称作"拉",即PULL)结合起来的混合式数据访问算法:自适应PUSH+PULL算法.与单纯的PUSH方式、PULL方式和简单的PUSH+PULL方式相比,这种算法具有更大的应用空间,使移动用户不仅能及时获得所需数据,而且仍然能够充分发挥无线通信网络所固有的数据广播能力,从而提高了移动数据库系统的可伸缩性.

  12. Next-Practise in University Research Based Open Innovation - From Push to Pull: Case Studies from Denmark

    DEFF Research Database (Denmark)

    Rønnow Lønholdt, Jens; Wilken Bengtsson, Mille; Karlby, Lone Tolstrup

    2013-01-01

    -graduate education at DTU in design and management of projects in network. It supports competence development within efficient knowledge transfer. Finally conclusions and recommendations will be presented and discussed based on the above six cases within university research based knowledge transfer. © Springer...... in different contextual settings at universities all over the world. Lessons learned are mixed and naturally varies from country to country. This paper presents a recently completed development project concerning the transfer facility at the Technical University of Denmark (DTU). The project focused...... on the pull function and the capacity development of the SMEs as this was the main lessons learned during the initial phase of the project. The paper also presents four Danish innovation projects that illustrate the use of the pull-based concept.Last but not least, the paper presents a new post...

  13. Synthesis and characterization of thermally stable second-order nonlinear optical side-chain polyimides containing thiazole and benzothiazole push-pull chromophores

    Science.gov (United States)

    Tambe, S. M.; Kittur, A. A.; Inamdar, S. R.; Mitchell, G. R.; Kariduraganavar, M. Y.

    2009-04-01

    Push-pull nonlinear optical (NLO) chromophores containing thiazole and benzothiazole acceptors were synthesized and characterized. Using these chromophores a series of second-order NLO polyimides were successfully prepared from 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), pyromellitic dianhydride (PMDA) and 3,3'4,4'-benzophenone tetracarboxylic dianhydride (BTDA) by a standard condensation polymerization technique. These polyimides exhibit high glass transition temperatures ranging from 160 to 188 °C. UV-vis spectrum of polyimide exhibited a slight blue shift and decreases in absorption due to birefringence. From the order parameters, it was found that chromophores were aligned effectively. Using in situ poling and temperature ramping technique, the optical temperatures for corona poling were obtained. It was found that the optimal temperatures of polyimides approach their glass transition temperatures. These polyimides demonstrate relatively large d33 values range between 35.15 and 45.20 pm/V at 532 nm.

  14. Design of ``push-pull'' p-type quinoid-based organic dyes with near-IR absorption: A density function theory study

    Science.gov (United States)

    Yang, Zhenqing; Li, Juan; Liu, Yun; Zhang, Wansong

    2017-04-01

    Based on an experimentally synthesized p-type dye QT-1, we screened and designed a series of quinoid-based "push-pull" dyes SPL401 - SPL407 by modifying the π-conjugated linker for ptype dye-sensitized solar cells (p-type DSSC). Further, we systematically calculated their electronic and optical properties by using the density functional theory (DFT) and the time-dependent DFT (TDDFT). The results indicate that compared to QT-1, SPL406 and SPL407, which have not only smaller energy gaps, higher oscillator strength f increased by 70% and 80%, and 141 nm and 110 nm redshifts, respectively, but also a broader absorption spectrum covering the entire visible range to the near-IR region of 1200 nm, may be the most promising candidates among SPL401 - SPL407 for p-type organic sensitizers.

  15. Push-pull Strategy with Trap Crops, Neem and Nuclear Polyhedrosis Virus for Insecticide Resistance Management in Helicoverpa armigera (Hubner in Cotton

    Directory of Open Access Journals (Sweden)

    P. Duraimurugan

    2005-01-01

    Full Text Available Insecticide resistance in Helicoverpa armigera (Hubner is a major threat to cotton production in India. The virus infection was found to increase the susceptibility of H. armigera to the insecticides. But, use of Nuclear Polyhedrosis Virus (NPV on a larger scale and on cotton due to leaf alkalinity poses certain practical problems. Hence, studies were carried out to assess the effects of push-pull strategy with trap crops, neem and NPV in cotton for the management of insecticide resistant H. armigera. Field experiments were conducted on cotton (MCU5 with trap crops (okra and pigeonpea and neem was used to diversify the pests to trap crops whereby the control of these pests was assessed with the application of NPV. The preference of H. armigera was towards okra and pigeonpea as a trap crop compared to cotton. Application of NSKE on cotton diversified the H. armigera towards untreated okra and pigeonpea. Push-pull strategy with the conjunctive use of trap crops, restricted application of NSKE on cotton leaving trap crops and restricted application of NPV on trap crops was highly effective in reducing the incidence of H. armigera and damage to fruiting bodies, boll, locule and inter locule basis over cotton sole crop (untreated check. The percent recovery of NPV infected larvae varied from 37.5-47.5, 32.8-39.2 and 14.2-20.2% on okra, pigeon pea and cotton respectively. The synthetic pyrethroids resistance in field survived H. armigera at the end of the season was reduced from 87.5-93.1% to 76.4-84.3%.

  16. Heat as a tracer for understanding transport processes in fractured media: Theory and field assessment from multiscale thermal push-pull tracer tests

    Science.gov (United States)

    Klepikova, Maria V.; Le Borgne, Tanguy; Bour, Olivier; Dentz, Marco; Hochreutener, Rebecca; Lavenant, Nicolas

    2016-07-01

    The characterization and modeling of heat transfer in fractured media is particularly challenging as the existence of fractures at multiple scales induces highly localized flow patterns. From a theoretical and numerical analysis of heat transfer in simple conceptual models of fractured media, we show that flow channeling has a significant effect on the scaling of heat recovery in both space and time. The late time tailing of heat recovery under channeled flow is shown to diverge from the T>(t>)∝t-1.5 behavior expected for the classical parallel plate model and follow the scaling T>(t>)∝1/t>(log⁡t>)2 for a simple channel modeled as a tube. This scaling, which differs significantly from known scalings in mobile-immobile systems, is of purely geometrical origin: late time heat transfer from the matrix to a channel corresponds dimensionally to a radial diffusion process, while heat transfer from the matrix to a plate may be considered as a one-dimensional process. This phenomenon is also manifested on the spatial scaling of heat recovery as flow channeling affects the decay of the thermal breakthrough peak amplitude and the increase of the peak time with scale. These findings are supported by the results of a field experimental campaign performed on the fractured rock site of Ploemeur. The scaling of heat recovery in time and space, measured from thermal breakthrough curves measured through a series of push-pull tests at different scales, shows a clear signature of flow channeling. The whole data set can thus be successfully represented by a multichannel model parametrized by the mean channel density and aperture. These findings, which bring new insights on the effect of flow channeling on heat transfer in fractured rocks, show how heat recovery in geothermal tests may be controlled by fracture geometry. In addition, this highlights the interest of thermal push-pull tests as a complement to solute tracers tests to infer fracture aperture and geometry.

  17. The application research of MRP and JIT push-pull combinative production management%MRP与JIT推拉结合生产管理应用研究

    Institute of Scientific and Technical Information of China (English)

    于世坤; 王波

    2012-01-01

    MRP is a good "push" type of production planning system, while JIT is a good "pull" operation control system,so the combination of both modes has been a research hotspot and has gradually been adopted by some companies. Start from the features of MRP and JIT production management. First, studies the complementary strengths and weaknesses between the two modes. Then,design a push-pull combination of MRP and JIT production model and implementation of programs and combined with features of auto parts industry,to analyze the effectiveness of this new model. The results showed that;the combination of MRP and JIT production modes has brought great improvement to the enterprise production planning, inventory management,flexible production and achieved good results.%物料需求计划(MRP)是一个良好的“推”式生产计划系统,准时生产(JIT)是一个良好的“拉”式作业控制系统,两者结合的生产方式一直是研究的热点,也逐渐被一些企业采用.从MRP与JIT的生产管理特点入手,研究两者的优劣势互补性,设计MRP与JIT推拉结合生产模式和执行方案,并结合汽配行业特点,分析这种新模式的有效性.结果表明:两者结合的生产模式给企业生产计划、库存管理和柔性化生产带来了很大改进,取得了不错的成效.

  18. Push and pull models to manage patient consent and licensing of multimedia resources in digital repositories for case-based reasoning.

    Science.gov (United States)

    Kononowicz, Andrzej A; Zary, Nabil; Davies, David; Heid, Jörn; Woodham, Luke; Hege, Inga

    2011-01-01

    Patient consents for distribution of multimedia constitute a significant element of medical case-based repositories in medicine. A technical challenge is posed by the right of patients to withdraw permission to disseminate their images or videos. A technical mechanism for spreading information about changes in multimedia usage licenses is sought. The authors gained their experience by developing and managing a large (>340 cases) repository of virtual patients within the European project eViP. The solution for dissemination of license status should reuse and extend existing metadata standards in medical education. Two methods: PUSH and PULL are described differing in the moment of update and the division of responsibilities between parties in the learning object exchange process. The authors recommend usage of the PUSH scenario because it is better adapted to legal requirements in many countries. It needs to be stressed that the solution is based on mutual trust of the exchange partners and therefore is most appropriate for use in educational alliances and consortia. It is hoped that the proposed models for exchanging consents and licensing information will become a crucial part of the technical frameworks for building case-based repositories.

  19. Evaluation of a push-pull approach for Aedes aegypti(L.) using a novel dispensing system for spatial repellents in the laboratory and in a semi-field environment

    Science.gov (United States)

    The increase in insecticide resistant mosquito populations necessitates the exploration of novel vector control intervention measures. Push-pull strategies for insect control have been successful when used in integrated crop pest management. Through the combinatory use of deterring and attracting st...

  20. A Novel Thin Client Architecture with Hybrid Push-Pull Model, Adaptive Display Pre-Fetching and Graph Colouring

    Directory of Open Access Journals (Sweden)

    Sumalatha.M.R

    2016-06-01

    Full Text Available The advent of cloud computing has driven away the notion of having sophisticated hardware devices for performing computing intensive tasks. This feature is very essential for resource-constrained devices. In mobile cloud computing, it is sufficient that the device be a thin client i.e. which concentrates solely on providing a graphical user interface to the end-user and the processing is done in the cloud. We focus on adaptive display virtualization where the display updates are computed in advance using synchronization techniques and classifying the job as computationally intensive or not based on the complexity of the program and the interaction pattern. Based on application, the next possible key-press is identified and those particular frames are pre-fetched into the local buffer. Based on these two factors, a decision is then made whether to execute the job locally or in the cloud or whether we must take the next frame from the local buffer or pull it from server. Jobs requiring greater interaction are executed locally in the mobile to reduce interaction delay. If a job is to be executed in the cloud, then the results of the processing alone are sent via the network to the device. The parameters are varied in runtime based on network conditions and application parameters to minimise the interaction delay.

  1. Push-pull-like effects of physiological reaction to hypoxia%低氧生理反应的"类推拉效应"实验观察

    Institute of Scientific and Technical Information of China (English)

    杨军; 俞梦孙; 李晔; 王海涛; 曹征涛; 张宏金

    2011-01-01

    [ Abstract ] Objective To simulate the push - pull - like effects of physiological reaction to hypoxia, viz. The human physiological reaction when the environment is rapidly switched from high oxygen partial pressure to low oxygen partial pressure. Methods Six young male volunteers underwent two kinds of environments, I. E. They were switched from the normal pressure and normoxia condition and the normal pressure and 50% high oxygen partial pressure condition to the low oxygen partial pressure condition ( 12.9% ,simulation of 4 km above the sea level ), respectively. Afterwards, all volunteers sat silently for 30 min. During the whole process, the physiological parameters of these volunteers, such as saturation of blood oxygen, heart rate and respiratory wave, etc, were continuously measured. Results ( 1 ) Compared with the condition switched from normoxia to hypoxia, the decrease range of the volunteers'SpO2 was more obvious when the environment was switched from hyperxia to hypoxia. ( 2 ) The changing time of oxygen partial pressure was 2 min. ( 3 ) There were significant individual differences in the volunteers' reaction patterns and tendency of physiological parameters. Conclusion The self - designed normal - pressure and hypoxia cabin is feasible. The push - pull - like effects of physiological reaction to hypoxia are simulated preliminarily and some valuable physiological parameters are observed, which provides basic data for further research and alleviating the adverse influence caused by push - pull - like effects on flying personnel.%目的 模拟低氧生理反应的"类推拉效应",即从高氧分压环境快速切换至低氧分压环境时的人体生理反应.方法 实验对象为6位青年男性,分别经历由常压常氧和常压50%高氧分压环境阶跃式切换到低氧分压(12.9%,模拟4 km海拔)环境,静坐30 min.整个过程连续测量其血氧饱和度、心率、呼吸波等生理参数.结果 (1)比较由常氧至低氧环境,受

  2. Steady-state Manoeuvring of a Generic ASD Tug in Escort Pull and Bow-rope Aided Push Operation

    Directory of Open Access Journals (Sweden)

    Jaroslaw Artyszuk

    2014-09-01

    Full Text Available This paper is devoted to expand the very promising research undertaken in the author's previous work, basically done on simplified modelling the escort push operation. Now, the other two modes of a tug's employment, as stated in the title, are covered. The special focus is again set on the indirect towing in that the towline force is much higher than the thruster force. The ratio of these two forces, referred to as the relative towing force (or amplification ratio is evaluated together with the hull drift angle and the thruster(-s angle for a given escort speed. This mutual relationship is known as the tug performance diagram. Although rather generic (container-type formulas are derived, they are supplied for exemplification purposes with simple, analytically given hull hydrodynamic forces. The aim is also here to provide a basis for further sensitivity analysis of the model and possible improvement/optimisation to the tug design. The obtained charts also could serve as rough and clear guidance for towmasters while escorting.

  3. 浅析挤扩多盘桩单桩竖向抗拔承载力%ANALYSISON THE PUSH-EXTEND MULTI-UNDER-REAMED PILE BEARING CAPACITY OF SINGLE PILE PULLED ON VERTICAL LOADS

    Institute of Scientific and Technical Information of China (English)

    任佳佳; 钱永梅; 尹新生

    2012-01-01

    通过研究挤扩多盘桩的现有抗拔承载力计算方法,提出利用传统模式来计算挤扩多盘桩的抗拔承载力的不足之处,并根据挤扩多盘桩在竖向拔力作用下的土体的破坏特征和桩的受力机理,提出最新的挤扩多盘桩抗拔承载力的计算模式,为该型桩的设计应用提供可靠的理论依据。%By studying the existing calculation method of pulled out of the bearing capacity of the push-extend multi-under- reamed pile, this article put forward deficiencies of the traditional mode to calculate the bearing capacity of the push-extend multi-under-reamed pile, and according to the push-extend multi-under-reamed pile under vertical pull force the characteristics of the soil destruction and working mechanism of pile, put forward the newest calculation method of pulled out of the bearing capacity of the push-extend multi-under-reamed pile, the reliable theory basis will influence the application of the expansion multiple disk pile.

  4. Design of an expert system for the development and formulation of push-pull osmotic pump tablets containing poorly water-soluble drugs.

    Science.gov (United States)

    Zhang, Zhi-hong; Dong, Hong-ye; Peng, Bo; Liu, Hong-fei; Li, Chun-lei; Liang, Min; Pan, Wei-san

    2011-05-30

    The purpose of this article was to build an expert system for the development and formulation of push-pull osmotic pump tablets (PPOP). Hundreds of PPOP formulations were studied according to different poorly water-soluble drugs and pharmaceutical acceptable excipients. The knowledge base including database and rule base was built based on the reported results of hundreds of PPOP formulations containing different poorly water-soluble drugs and pharmaceutical excipients and the experiences available from other researchers. The prediction model of release behavior was built using back propagation (BP) neural network, which is good at nonlinear mapping and learning function. Formulation design model was established based on the prediction model of release behavior, which was the nucleus of the inference engine. Finally, the expert system program was constructed by VB.NET associating with SQL Server. Expert system is one of the most popular aspects in artificial intelligence. To date there is no expert system available for the formulation of controlled release dosage forms yet. Moreover, osmotic pump technology (OPT) is gradually getting consummate all over the world. It is meaningful to apply expert system on OPT. Famotidine, a water insoluble drug was chosen as the model drug to validate the applicability of the developed expert system. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Geometry and bond-length alternation in nonlinear optical materials. II. Effects of donor strength in two push-pull molecules.

    Science.gov (United States)

    Gainsford, Graeme J; Bhuiyan, M Delower H; Kay, Andrew J

    2008-04-01

    The compounds N-[2-(4-cyano-5-dicyanomethylene-2,2-dimethyl-2,5-dihydrofuran-3-yl)vinyl]-N-phenylacetamide, C(20)H(16)N(4)O(2), (I), and 2-{3-cyano-5,5-dimethyl-4-[2-(piperidin-1-yl)vinyl]-2,5-dihydrofuran-2-ylidene}malononitrile 0.376-hydrate, C(17)H(18)N(4)O x 0.376 H(2)O, (II), are novel push-pull molecules. The significant bonding changes in the polyene chain compared with the parent molecule 2-dicyanomethylene-4,5,5-trimethyl-2,5-dihyrofuran-3-carbonitrile are consistent with the relative electron-donating properties of the acetanilido and piperidine groups. The packing of (I) utilizes one phenyl-cyano C-H...N and two phenyl-carbonyl C-H...O hydrogen bonds. Compound (II) crystallizes with a partial water molecule (0.376H(2)O), consistent with cell packing that is dominated by attractive C-H...N(cyano) interactions. These compounds are precursors to novel nonlinear optical chromophores, studied to assess the impact of donor strength and the extent of conjugation on bond-length alternation, crystal packing and aggregation.

  6. Push-Pull Type Porphyrin Based Sensitizers: The Effect of Donor Structure on the Light-Harvesting Ability and Photovoltaic Performance

    KAUST Repository

    Qi, Qingbiao

    2015-06-23

    Push-pull type porphyrin-based sensitizers have become promising candidates for high-efficiency dye sensitized solar cells (DSCs). It is of importance to understand the fundamental structure-physical property-photovoltaic performance relationships by varying the donor and acceptor moieties. In this work, two new porphyrin-based sensitizers, WW-7 and WW-8, were synthesized and compared with the known sensitizer YD20. All the three dyes have the same porphyrin core and acceptor group (ethynylbenzoic acid) but their donor groups vary from the triphenylamine in YD20 to meso-diphenylaminoanthracene in WW-7 to N-phenyl carbazole in WW-8. Co(II/III)-based DSC device characterizations revealed that WW-7 showed enhanced light harvesting ability in comparison to YD20 with improved incident photon-to-collected electron conversion efficiencies (IPCEs). As a result, WW-7 displayed much higher short circuit current (Jsc: 13.54 mA cm-2) and open-circuit voltage (Voc: 0.829 V), with a power conversion efficiency (η) as high as 7.7%. Under the same conditions, YD20 cell exhibited a power conversion efficiency of 6.6% and the dye WW-8 showed even lower efficiency (η = 4.6%). Detailed physical measurements and theoretic calculations were conducted to understand the difference and reveal how three different donor structures affect their molecular orbital profile, light-harvesting ability, energy level alignment, and eventually the photovoltaic performance.

  7. Characterizing volatiles and attractiveness of five brassicaceous plants with potential for a 'push-pull' strategy toward the cabbage root fly, Delia radicum.

    Science.gov (United States)

    Kergunteuil, Alan; Dugravot, Sébastien; Danner, Holger; van Dam, Nicole M; Cortesero, Anne Marie

    2015-04-01

    Volatile Organic Compounds (VOCs) released by plants are involved in various orientation processes of herbivorous insects and consequently play a crucial role in their reproductive success. In the context of developing new strategies for crop protection, several studies have previously demonstrated the possibility to limit insect density on crops using either host or non-host plants that release attractive or repellent VOCs, respectively. The cabbage root fly, Delia radicum, is an important pest of brassicaceous crops for which control methods have to be implemented. Several studies have shown that plant odors influence cabbage root fly behavior, but only few VOCs have been identified so far. The present study aimed at selecting both plants and olfactory stimuli that could be used in the development of a "push-pull" strategy against the cabbage root fly. Olfactometer results revealed that plants belonging to the same family, even to the same species, may exhibit different levels of attractiveness toward D. radicum. Plants that were found attractive in behavioral observations were characterized by high release rates of distinct terpenes, such as linalool, β-caryophyllene, humulene, and α-farnesene. This study represents a first step to identify both attractive plants of agronomic interest, and additional volatiles that could be used in the context of trap crops to protect broccoli fields against the cabbage root fly.

  8. Comparison of Aedes aegypti (Diptera: Culicidae) resting behavior on two fabric types under consideration for insecticide treatment in a push-pull strategy.

    Science.gov (United States)

    Tainchum, Krajana; Polsomboon, Suppaluck; Grieco, John P; Suwonkerd, Wannapa; Prabaripai, Atchariya; Sungvornyothin, Sungsit; Chareonviriyaphap, Theeraphap; Achee, Nicole L

    2013-01-01

    Aedes aegypti (L.), the primary vector of dengue and dengue hemorrhagic fever, breeds and rests predominately inside human dwellings. With no current vaccine available, vector control remains the mainstay for dengue management and novel approaches continue to be needed to reduce virus transmission. This requires a full understanding of Ae. aegypti ecology to design effective strategies. One novel approach is the use of contact irritants at target resting sites inside homes to make the surface unacceptable and cause vectors to escape before biting. The objective of the current study was to observe indoor resting behavior patterns of female Ae. aegypti within experimental huts in response to two fabrics under consideration for insecticide treatment: cotton and polyester. Results indicate that fabric type, coverage ratio of dark to light fabric and placement configuration (vertical vs. horizontal) all influenced the resting pattern of mosquito cohorts. Findings from this study will guide evaluations of a push-pull strategy designed to exploit contact irritant behaviors and drive Ae. aegypti out of homes prefeeding.

  9. Assessing the quantum mechanical level of theory for prediction of linear and nonlinear optical properties of push-pull organic molecules.

    Science.gov (United States)

    Paschoal, Diego; Santos, Hélio F Dos

    2013-05-01

    In this paper, we assessed the quantum mechanical level of theory for prediction of linear and nonlinear optical (NLO) properties of push-pull organic molecules. The electric dipole moment (μ), mean polarizability ([Symbol: see text]α[Symbol: see text]) and total static first hyperpolarizability (βt) were calculated for a set of benzene, styrene, biphenyl and stilbene derivatives using HF, MP2 and DFT (31 different functionals) levels and over 71 distinct basis sets. In addition, we propose two new basis sets, NLO-V and aNLO-V, for NLO properties calculations. As the main outcomes it is shown that long-range corrected DFT functionals such as M062X, ωB97, cam-B3LYP, LC-BLYP and LC-ωPBE work satisfactorily for NLO properties when appropriate basis sets such as those proposed here (NLO-V or aNLO-V) are used. For most molecules with β ranging from 0 to 190 esu, the average absolute deviation was 13.2 esu for NLO-V basis sets, compared to 27.2 esu for the standard 6-31 G(2d) basis set. Therefore, we conclude that the new basis sets proposed here (NLO-V and aNLO-V), together with the cam-B3LYP functional, make an affordable calculation scheme to predict NLO properties of large organic molecules.

  10. Time dependent density functional theory investigation of the resonance Raman properties of the julolidinemalononitrile push-pull chromophore in various solvents.

    Science.gov (United States)

    Guthmuller, Julien; Champagne, Benoît

    2007-10-28

    The absorption and resonance Raman spectra have been investigated for the first excited state of the julolidinemalononitrile push-pull chromophore in cyclohexane, dichloromethane, and acetonitrile by means of time dependent density functional theory calculations. The effect of nonlocal exchange has been considered by using three different hybrid exchange-correlation functionals containing 20%, 35%, and 50% of exact Hartree-Fock exchange. The interactions with the solvent have been described by the polarizable continuum model. The short-time approximation expression has been used to evaluate the resonance Raman intensities, while the vibronic theory of resonance Raman spectroscopy has been employed to determine both the intensities and the excitation profiles. It is shown that a consistent description of the vibronic structure of the excited state and resonance Raman spectra can be obtained provided that an adequate amount, close to 35%, of exact exchange is included in the exchange-correlation functional. The effect of increasing the polarity of the solvent is well represented by the polarizable continuum model, both for the absorption spectra and resonance Raman intensities. In particular, these simulations can reproduce the observed variations of the 1560 cm(-1) band intensity and attribute them to elongations of a CC double bond upon electronic excitation. Moreover, the short-time approximation has been found sufficient to reproduce most of the results of the more evolved vibronic theory of resonance Raman spectroscopy, which includes summations over vibrational excited states, for both the spectral signatures and their solvent dependencies.

  11. Ergonomic study regarding sport trainingPush-ups simulation and analysis

    OpenAIRE

    Ion S. BOROZAN; Paul I. MIRON

    2012-01-01

    Some of the most common and helpful physical exercises used in sport training are the push-ups. Their biomechanics is analyzed in the paper and the author also gives an ergonomical study of this particular exercise with a complete simulation of the process.

  12. Ergonomic study regarding sport trainingPush-ups simulation and analysis

    Directory of Open Access Journals (Sweden)

    Ion S. BOROZAN

    2012-06-01

    Full Text Available Some of the most common and helpful physical exercises used in sport training are the push-ups. Their biomechanics is analyzed in the paper and the author also gives an ergonomical study of this particular exercise with a complete simulation of the process.

  13. A push-pull vaccine strategy using Toll-like receptor ligands, IL-15, and blockade of negative regulation to improve the quality and quantity of T cell immune responses.

    Science.gov (United States)

    Berzofsky, Jay A

    2012-06-19

    We have developed a strategy to optimize the efficacy of vaccines to induce T-cell immunity against chronic viral infections and cancer based on a "push-pull" approach in which we first optimize the antigen structure by increasing the affinity of epitopes for major histocompatibility complex molecules ("epitope enhancement"), then push the response not only in magnitude but also in quality toward the desired response phenotype, using synergistic combinations of cytokines, Toll-like receptor ligands, and costimulatory molecules, and then pull the response by removing the brakes exerted by negative regulatory mechanisms, including regulatory cells, cell surface molecules, and cytokines. Components of this approach show promise in macaque models of AIDS virus infection and in murine models of cancer, and are being developed for human clinical trials.

  14. 有源钳位推挽变换器控制策略的研究%Research on the Control Strategy of the Active Clamped Push-pull Converter

    Institute of Scientific and Technical Information of China (English)

    朱景全; 李媛

    2014-01-01

    As the leakage inductance of the transformer will place an overvoltage at the switching devices in conventional push-pull convert-er ,the active clamped push-pull converter can greatly suppress this phenomenon .This paper analysis the mathematics model of push-pull con-verter ,adjust a proper value of the PI voltage feedback in the active clamped push-pull converter with second order engineering design method , and ensue this converter can work stably and efficiently with a suppression to the overvoltage at switching devices confirmed by simulation and experiment .%针对常规推挽变换器中变压器的漏感会在开关管两端产生电压尖峰的问题,有源钳位推挽变换器可以有效地对此现象进行抑制。本文对推挽变换器的数学模型进行分析,使用二阶工程设计法整定有源钳位推挽变换器中的电压负反馈PI调节的参数值,并且通过仿真与实验的验证,确保有源钳位推挽变换器可以稳定高效地运行,同时消除了由变压器漏感引起的开关管两端电压尖峰。

  15. 推挽DC-DC变换器平均电流控制研究%Research of Average Current Mode Control Based on Push-pull DC-DC Converter

    Institute of Scientific and Technical Information of China (English)

    桂存兵; 谢运祥; 谢涛; 陈江辉

    2012-01-01

    In order to improve the current stability and reliability of the push-pull converter, this paper ana-lyzed the push-pull DC/DC converter operational principle, and on this basis, built its small signal mathe-matical model. With imposing the current-mode dual-loop control strategy into its control system, improved the system dynamic response and protection ability. It has given the design process of the control system of push-pull converter, simulation and experimental research also has been done in the paper. The simulation and experimental results showed that, in view of the push-pull converter, the dual-loop control strategy has got a good dynamic and static control performance.%该文为提高推挽变换器的电流稳定性和系统可靠性,通过分析了DC/DC推挽变换器的工作原理,在此基础上建立了小信号数学模型.并施以电流型双环控制策略,有效的提高系统的动态响应和保护能力.给出了推挽变换器的控制系统的设计过程,并进行了仿真和实验研究,结果表明针对推挽变换器,双环控制策略具有良好动态和静态控制性能.

  16. 新时期中国农民工融入城市的推拉力分析%Analysis of Push-Pull Effort to Chinese Migrant Workers Integratation into City in New Times

    Institute of Scientific and Technical Information of China (English)

    魏卓

    2014-01-01

    The paper detailedly analyzed the push-pull effort of city and country to migrant workers during China ’ s urbani-zation process .Along with our country ’ s economic development , the push-pull effort of city and country to migrant workers is showing a more complex situation .Overall, the pull of city and push of country still play the main role in urbanization process,promoting migrant workers integratation into city .%文章详细阐述了当前我国农民工在融入城市的过程中,城市与农村对农民工的推、拉力作用。分析认为,随着我国经济的发展变革,城市与农村对农民工进城的拉力和推力也正在发生变革,呈现出更为复杂的情况。总体上,城市对农民工的拉力和农村对农民工的推力仍起主要作用,促进了农民工的城市融入。

  17. “推拉理论”视域下的地方本科院校师资队伍建设%Construction of Teaching Staff in Local Undergraduate Colleges and Universities from the Perspective of "Push- Pull Theory"

    Institute of Scientific and Technical Information of China (English)

    任奇; 冯东

    2012-01-01

    "推拉理论"是社会学领域研究人口流动的重要理论,剖析推拉作用力系统中的方向、形式、主体等构成要素,有利于优化高校师资队伍结构。高校师资队伍结构是一个系统工程,它涉及多个参与主体,要实现高校教师队伍的合理流动,就要在主体间建立畅通的反馈机制,真正发挥他们在推拉理论中的主体作用。%" Push - Pull Theory" is an important theory which is used for the study of population mobility in the field of sociology. The analysis of the direction, form, main body and other elements in the push and pull force system, is conducive to optimizing the structure of college teachers. The structure of college teachers belongs to system engi- neering, involving a number of participants, in order to realize the reasonable flow of teachers in colleges and uni- versities, the feedback mechanism between the main bodies should be established so that they can play their princi- pal role in the "Push -Pull Theory".

  18. Paramagnetic 13C and 15N NMR analyses of the push and pull effects in cytochrome c peroxidase and Coprinus cinereus peroxidase variants: functional roles of highly conserved amino acids around heme.

    Science.gov (United States)

    Nonaka, Daisuke; Wariishi, Hiroyuki; Welinder, Karen G; Fujii, Hiroshi

    2010-01-12

    Paramagnetic (13)C and (15)N nuclear magnetic resonance (NMR) spectroscopy of heme-bound cyanide ((13)C(15)N) was applied to 11 cytochrome c peroxidase (CcP) and Coprinus cinereus peroxidase (CIP) mutants to investigate contributions to the push and pull effects of conserved amino acids around heme. The (13)C and (15)N NMR data for the distal His and Arg mutants indicated that distal His is the key amino acid residue creating the strong pull effect and that distal Arg assists. The mutation of distal Trp of CcP to Phe, the amino acid at this position in CIP, changed the push and pull effects so they resembled those of CIP, whereas the mutation of distal Phe of CIP to Trp changed this mutant to become CcP-like. The (13)C NMR shifts for the proximal Asp mutants clearly showed that the proximal Asp-His hydrogen bonding strengthens the push effect. However, even in the absence of a hydrogen bond, the push effect of proximal His in peroxidase is significantly stronger than in globins. Comparison of these NMR data with the compound I formation rate constants and crystal structures of these mutants showed that (1) the base catalysis of the distal His is more critical for rapid compound I formation than its acid catalysis, (2) the primary function of the distal Arg is to maintain the distal heme pocket in favor of rapid compound I formation via hydrogen bonding, and (3) the push effect is the major contributor to the differential rates of compound I formation in wild-type peroxidases.

  19. Demonstration of In situ Anaerobic Transformation of Toluene and Xylene Using Single-Well Push-Pull Tests and Deuterated BTEX Surrogates

    Science.gov (United States)

    Field, J. A.; Reusser, D. E.; Beller, H. R.; Istok, J. D.

    2001-12-01

    Obtaining unambiguous evidence of in-situ transformation of benzene, toluene, ethylbenzene and xylene (BTEX) in the subsurface is a difficult task. Recently, benzylsuccinic acid and its methyl analogues were shown to be unequivocal degradation products of anaerobic toluene and xylene biodegradation. Conducting tracer tests at BTEX-contaminated field sites is problematic because background contaminant concentrations potentially interfere with the interpretation of field test data. To avoid the time and cost associated with removing background contaminants, alternative approaches are needed. Deuterated analogs of toluene and xylene are well-suited for use in field tracer tests because they are inexpensive and can be distinguished analytically from background toluene and xylene. In this study, single-well push-pull tests, in which deuterated toluene and xylene were injected, were performed to assess the in-situ anaerobic biotransformation of toluene and xylene in BTEX-contaminated wells. A total of 4 single-well push-pull tests were conducted at BTEX-contaminated field sites near Portland, OR and Kansas City, KS. Test solutions consisting of 100 mg/L bromide, 250 mg/L nitrate, 0.4 to 2.5 mg/L toluene-d8, and 0.4 to 1.0 mg/L o-xylene-d10.were injected at a rate of 0.5 - 2 L/min. During the extraction phase, samples were taken daily to biweekly for up to 30 days. Samples for volatile organic analytes were collected in 40-mL volatile organic analysis (VOA) vials without headspace. Samples for BSA and methyl-BSA were collected in 1 L glass bottles and preserved with 5% (w/w) formalin. Samples were shipped on ice and stored at 4 C until analysis. Unambiguous evidence of toluene and xylene biotransformation was obtained with the in-situ formation of BSA and methyl-BSA. The concentrations of BSA ranged from below the detection limit (0.2 ug/L) to 1.5 ug/L. The concentrations of methyl-BSA ranged from below detection to the quantitation limit (0.7 ug/L). The highest BSA

  20. Experimental and theoretical studies of the influence of solvent polarity on the spectral properties of two push-pull oxazol-5-(4H)-one compounds.

    Science.gov (United States)

    Jędrzejewska, Beata; Krawczyk, Przemysław; Józefowicz, Marek

    2017-01-15

    Spectral and photophysical properties of two derivatives of the 2-phenyl-1,3-oxazol-5(4H)-ones were studied in 17 solvents of different polarity. These compounds have either push-pull non-centrosymmetric or C3-symmetric structures with electron-withdrawing groups (2-phenyl-oxazolone) introduced onto the triphenylamine. It has been found that their spectral and photophysical properties depend on the structure of the compounds and on the solvent polarity. The non-radiative relaxation process is facilitated by an increase of the solvent polarity. The changes in the electronic absorption and fluorescence maximum positions with solvent polarity were analyzed applying different solvent polarity parameters based on Lippert-Mataga, McRae, Bakhshiev and Kawski theories or ET(N) scale. The long-wavelength absorption band positions exhibit a slight dependence on the solvent, whereas the fluorescence spectra demonstrate substantial positive solvatochromism. It was found that the position of the electronic absorption band depends mainly on the solute polarizability (related to the solvent refraction index function f(n(2))=(n(2)-1)/(2n(2)+1)), whereas the solvent polarity influences the position of the fluorescence band. Quantum chemical calculations of the transition energies and dipole moments at the DFT level have been also performed. The difference between the first excited and ground state dipole moments was found experimentally to be 10.8 D and 13.0 D according to Bakhshiev's model. The experimental values of Δμ were compared to that one obtained from theoretical calculations for various solvents.

  1. The influence of the push-pull effect and a π-conjugated system in conversion efficiency of bis-chalcone compounds in a dye sensitized solar cell

    Science.gov (United States)

    Teo, Kien Yung; Tiong, Mee Hing; Wee, Hung Yee; Jasin, Nornadia; Liu, Zhi-Qiang; Shiu, Ming Yang; Tang, Jyun Yang; Tsai, Jenn-Kai; Rahamathullah, Rafizah; Khairul, Wan M.; Tay, Meng Guan

    2017-09-01

    Chalcone and its related compounds are known to be π-conjugated compounds, which can be potentially used in different electronic areas include dye sensitized solar cell (DSSC). A total of six bis-chalcone compounds (1-6) have been synthesized using a Claisen-Schmidt condensation method under basic conditions. The compounds were used as the dye in DSSC to test their solar conversion efficiency. In the process of solar cell fabrication, titanium(II) oxide (TiO2) coated glass was used as the working electrode, whereas the mixture of iodine (I2), lithium iodide (LiI), 4-tertbutylpyridine (4-TBP) and 1,2-dimethyl-3-propylimidazolium (DMPII) in 3-methoxypropionitrile were used as the electrolyte. The DSSC was fabricated by immersing the TiO2 glass into the respective bis-chalcone compound solution and dried into the oven at 45 °C for 120 min. Lastly, the working electrode and counter electrode were sealed using surlyn of 60 μm thickness. The efficiency test was conducted under AM 1.5G illumination with the incident light intensity of 100 mW/cm2. Among the six bis-chalcone derivatives, compound 2, namely 1,4-bis-2-hydroxychalcone, was recorded with the highest efficiency (0.054%) compared to the others (0.022-0.035%). The presence of a π-conjugated system and the push-pull effect in the molecule were found to enhance the conversion efficiency of DSSC. Details of the results are discussed in the present paper.

  2. Experimental and theoretical studies of the influence of solvent polarity on the spectral properties of two push-pull oxazol-5-(4H)-one compounds

    Science.gov (United States)

    Jędrzejewska, Beata; Krawczyk, Przemysław; Józefowicz, Marek

    2017-01-01

    Spectral and photophysical properties of two derivatives of the 2-phenyl-1,3-oxazol-5(4H)-ones were studied in 17 solvents of different polarity. These compounds have either push-pull non-centrosymmetric or C3-symmetric structures with electron-withdrawing groups (2-phenyl-oxazolone) introduced onto the triphenylamine. It has been found that their spectral and photophysical properties depend on the structure of the compounds and on the solvent polarity. The non-radiative relaxation process is facilitated by an increase of the solvent polarity. The changes in the electronic absorption and fluorescence maximum positions with solvent polarity were analyzed applying different solvent polarity parameters based on Lippert-Mataga, McRae, Bakhshiev and Kawski theories or ETN scale. The long-wavelength absorption band positions exhibit a slight dependence on the solvent, whereas the fluorescence spectra demonstrate substantial positive solvatochromism. It was found that the position of the electronic absorption band depends mainly on the solute polarizability (related to the solvent refraction index function f(n2) = (n2-1) / (2n2 + 1)), whereas the solvent polarity influences the position of the fluorescence band. Quantum chemical calculations of the transition energies and dipole moments at the DFT level have been also performed. The difference between the first excited and ground state dipole moments was found experimentally to be 10.8 D and 13.0 D according to Bakhshiev's model. The experimental values of Δμ were compared to that one obtained from theoretical calculations for various solvents.

  3. Electronic Excitations in Push-Pull Oligomers and Their Complexes with Fullerene from Many-Body Green's Functions Theory with Polarizable Embedding.

    Science.gov (United States)

    Baumeier, Björn; Rohlfing, Michael; Andrienko, Denis

    2014-08-12

    We present a comparative study of excited states in push-pull oligomers of PCPDTBT and PSBTBT and prototypical complexes with a C60 acceptor using many-body Green's functions theory within the GW approximation and the Bethe-Salpeter equation. We analyze excitations in oligomers up to a length of 5 nm and find that for both materials the absorption energy practically saturates for structures larger than two repeat units due to the localized nature of the excitation. In the bimolecular complexes with C60, the transition from Frenkel to charge transfer excitons is generally exothermic and strongly influenced by the acceptor's position and orientation. The high CT binding energy of the order of 2 eV results from the lack of an explicit molecular environment. External polarization effects are then modeled in a GW-BSE based QM/MM approach by embedding the donor-acceptor complex into a polarizable lattice. The lowest charge transfer exciton is energetically stabilized by about 0.5 eV, while its binding energy is reduced to about 0.3 eV. We also identify a globally unbound charge transfer state with a more delocalized hole at higher energy while still within the absorption spectrum, which opens another potential pathway for charge separation. For both PCPDTBT and PSBTBT, the energetics are largely similar with respect to absorption and the driving force to form intermediate charge transfer excitations for free charge generation. These results support that the higher power conversion efficiency observed for solar cells using PSBTBT as donor material is a result of molecular packing rather than of the electronic structure of the polymer.

  4. Copper(II) complexes of salen analogues with two differently substituted (push-pull) salicylaldehyde moieties. A study on the modulation of electronic asymmetry and nonlinear optical properties.

    Science.gov (United States)

    Rigamonti, Luca; Demartin, Francesco; Forni, Alessandra; Righetto, Stefania; Pasini, Alessandro

    2006-12-25

    This paper presents some copper(II) complexes of salen analogues in which the two salicylaldehyde moieties carry different (electron donor, D, and acceptor, A) substituents in position 5, producing a push-pull charge asymmetry. The X-ray structures of some compounds show the presence of pairs of stacked molecules with head-to-tail intermolecular associations. The geometries of all complexes have been optimized through density functional theory (DFT) studies, which have shown that a major influence on the coordination bond lengths is given by the presence of the electron acceptor NO2 group. Such an influence operates mainly on the Cu-phenolato bonds: elongation of the Cu-O distance of the 5-nitrosalicylaldehyde moiety, with a concomitant decrease of the other Cu-O distance; the Cu-N bonds are less affected. The D groups have only a minor influence. The nonlinear optical responses, microgBetavec, of some molecules have been determined by EFISH measurements, and the Beta-vec values have been obtained using the DFT-calculated microg values because solubility problems hampered the experimental measurements of microg of some derivatives; the former, however, have been found to be in agreement with the experimental values that could be obtained. Deconvolution of the absorption bands in the near-UV region has allowed recognition of the charge-transfer (CT) transition, assigned to a ligand-to-metal CT (LMCT) by time-dependent DFT computations; we have then used the solvatochromism of this transition to obtain Beta0 and BetaCT values using the two-state model. These values were compared with those obtained by computational studies, which have also allowed evaluation of the influence of the substituents on the directions of microg and Betatot.

  5. Multilevel push pull power converter

    DEFF Research Database (Denmark)

    2007-01-01

    and connected to the first supply potential, and at least one secondary winding magnetically coupled to the primary winding for providing at least one output voltage (Vout); and a first controllable switch connected between the second supply potential and one terminal of the primary winding and a second...... controllable switch connected between the second supply potential and the other terminal of the primary winding and a third controllable switch connected between the second supply potential and the one terminal of the primary winding and a fourth controllable switch connected between the second supply...... potential and the other terminal of the primary winding, and a control unit for controlling the switches such that the first, second, third, and fourth switches are turned on sequentially wherein at any time maximum one switch is turned on....

  6. AGGLOMERATION AND RADIATION EFFECT OF THE PULL OF URBANIZATION

    Institute of Scientific and Technical Information of China (English)

    QI Jin-li

    2003-01-01

    In order to explore the train of thought for China's urbanizing development and coordinated rural eco-nomic development, and to find good ways of solving rural problems through urbanization, this paper absorbs the push-and-pull forces theory and the systematic dynamic theory in the traditional population migration theories, views urbanization as a dynamic system, makes research on the push-and-pull mechanism of urbanization. The pull ingpower of urbanization is analyzed according to two aspects, the agglomeration effect and the radiation effect of cities. The agglomeration effect provides continuous propelling force for urbanization, and the radiation effect furtheraccelerates the urbanization process by pushing forward the development of rural economy. Of course, the slow de-velopment of urbanization can result in the hindrance to rural economic development.

  7. Combining Push Pull Tracer Tests and Microbial DNA and mRNA Analysis to Assess In-Situ Groundwater Nitrate Transformations

    Science.gov (United States)

    Henson, W.; Graham, W. D.; Huang, L.; Ogram, A.

    2015-12-01

    Nitrogen transformation mechanisms in the Upper Floridan Aquifer (UFA) are still poorly understood because of karst aquifer complexity and spatiotemporal variability in nitrate and carbon loading. Transformation rates have not been directly measured in the aquifer. This study quantifies nitrate-nitrogen transformation potential in the UFA using single well push-pull tracer injection (PPT) experiments combined with microbial characterization of extracted water via qPCR and RT-qPCR of selected nitrate reduction genes. Tracer tests with chloride and nitrate ± carbon were executed in two wells representing anoxic and oxic geochemical end members in a spring groundwater contributing area. A significant increase in number of microbes with carbon addition suggests stimulated growth. Increases in the activities of denitrification genes (nirK and nirS) as measured by RT-qPCR were not observed. However, only microbes suspended in the tracer were obtained, ignoring effects of aquifer material biofilms. Increases in nrfA mRNA and ammonia concentrations were observed, supporting Dissimilatory Reduction of Nitrate to Ammonia (DNRA) as a reduction mechanism. In the oxic aquifer, zero order nitrate loss rates ranged from 32 to 89 nmol /L*hr with no added carbon and 90 to 240 nmol /L*hr with carbon. In the anoxic aquifer, rates ranged from 18 to 95 nmol /L*hr with no added carbon and 34 to 207 nmol /L*hr with carbon. These loss rates are low; 13 orders of magnitude less than the loads applied in the contributing area each year, however they do indicate that losses can occur in oxic and anoxic aquifers with and without carbon. These rates may include, ammonia adsorption, uptake, or denitrification in aquifer material biofilms. Rates with and without carbon addition for both aquifers were similar, suggesting aquifer redox state and carbon availability alone are insufficient to predict response to nutrient additions without characterization of microbial response. Surprisingly, these

  8. Resonant push-pull DC-DC converter%一种谐振型推挽式直流变换器

    Institute of Scientific and Technical Information of China (English)

    袁义生; 龚昌为

    2012-01-01

    通过在变压器副边串联LC谐振器件,在谐振频率高于2倍开关频率时,电路能实现功率MOSFET的零电压开通和零电流关断,以及副边续流二极管的零电流关断.描述了电路软开关实现的具体过程.针对副边LC谐振过程中特有的n周期谐振现象,探索了其形成机理,推导了n周期谐振下输出电压、负载电阻及谐振电容电压之间的解析公式关系,归纳得到了变换器输出电压与输出电阻、输出电流之间的特性曲线,进而阐述了电路的应用范围及设计特点.最后制作了一台实验室样机,样机最多可工作在4周期谐振模式下,对不同负载、不同周期谐振工作状态的电路波形进行测试,验证了电路工作原理.%By inserting the LC resonant components in series at the secondary side of transformer and when the resonant frequency is higher than the doubled switching frequency, the zero voltage turning-on and zero current turning-off of MOSFET and the zero current turning-off of freewheeling diode can be realized in push-pull converter. The soft switching process is described and the generating mechanism of the /i-period resonance specially existing in secondary-side LC resonance is analyzed. The mathematic relationship between output voltage and load resistor(current) under n-period resonance is derived,the characteristic curve of output voltage vs. output current is demonstrated, and the application field and design features of the proposed converter are explained. The test of a laboratory prototype with different loads and under different period resonance modes,which can operate under up to four-period resonance mode,verifies the theoretical analysis.

  9. Research of Modeling and Control on Push-Pull Forward Converter%推挽正激变换器的建模与控制研究

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    This paper presents a push-pull forward converter, which can be used for the pre-isolated inverter and has some superiority in low voltage and high current situation. According to the principle of isolated DC/DC converter, small signal math model of PPF converter is established by using state-space averaging method under the assumption conditions of low-frequency, small signal and small ripple wave. Then the MATLAB software is used to carry through the assistant analysis, and design the control parameters and automatic closed control system based on the theoretical analysis. Finally, the simulation and experimental results show that the system(prototype) has perfect dynamic and static character, which verifies the validity of the mathematical model and the feasibility of the control strategy.%  本文给出了可用于隔离型逆变器前级DC/DC环节的方案—推挽正激变换器,通过研究隔离式DC/DC变换器的基本原理,在低频、小信号、小纹波条件下,利用状态空间平均法建立小信号模型。然后采用MATLAB软件进行辅助分析,设计了补偿电路,在此基础上搭建了推挽正激变换器的电压型闭环控制系统。最后进行了仿真和实验验证,实验结果表明所设计系统(样机)具有良好的动态性能和稳定性,进而验证了数学模型的正确性,采用控制策略的合理性以及设计方案的可行性。

  10. Vibrational and quantum-chemical study of push-pull chromophores for second-order nonlinear optics from rigidified thiophene-based pi-conjugating spacers.

    Science.gov (United States)

    Ruiz Delgado, Mari Carmen; Hernández, Víctor; Casado, Juan; López Navarrete, Juan T; Raimundo, Jean-Manuel; Blanchard, Philippe; Roncali, Jean

    2003-08-04

    Two types of push-pull chromophores built around thiophene-based pi-conjugating spacers rigidified by either covalent bonds or noncovalent intramolecular interactions have been analysed by means of IR and Raman spectroscopical measurements in the solid state as well as in a variety of solvents. Comparison of the Raman features of NLO-phores based on a covalently rigidified dithienylene (DTE) spacer with those of their open chain DTE analogues shows that the bridging of the central double bond of DTE with the nearest beta-positions of the thienyl units through two ethylene bridges significantly improves the intramolecular charge transfer. This also occurs for NLO-phores based on a 2,2'-bi(3,4-ethylenedioxythiophene) (BEDOT) spacer as compared with their corresponding parent compounds based on an unsubstituted bithiophene (BT) spacer. For NLO-phores based on a BEDOT spacer, noncovalent intramolecular interactions between sulfur and oxygen atoms are responsible for the rigidification of the spacer. The Raman spectra of these NLO-phores obtained in the form of solutes in dilute solutions reveal two different behaviours: i) chromophores based on covalently bridged or open chain DTE spacers display Raman spectral profiles in solution quite similar to those of the corresponding solids, with a very little dependence on the polarity of the solvent, while ii) larger spectral changes are noticed for NLO-phores built around BEDOT or BT spacers on going from solids to solutions. In the second case, spectral changes must be ascribed not solely to conformational distortions of the donor and acceptor end groups with respect to the pi-conjugated backbone mean-square-plane (as for the DTE-based NLO-phores) but also to distortions of the thienyl units of the pi-conjugating spacer from coplanarity. The insertion of vinylenic bridges between the thienyl units of the pi-conjugating spacer and between the spacer and the donor and acceptor end groups is a suitable strategy to reach a

  11. Push-pull type of high-frequency inverter with voltage controllability by using short-circuit mode and its application to high-frequency lighting circuit of electric-discharge lamp. Tanraku modo wo mochiita kaseigyo push pull koshuha inverter to hoden ranpu koshuha tento kairo eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Funabiki, S.; Komatsubara, H. (Okayama Univ., Okayama (Japan)); Kanbara, T.; Tanigawa, K. (Matsushita Electric Works Ltd., Osaka (Japan))

    1994-04-20

    In recent years, in order to compact the inverter and to make high-function of the inverter used in electric-discharge lamp, the electronic-inverter with high-frequency is improved. There are some problems in the high-frequency inverter that surge and noise occur when switch loss increases and voltage is intermitted abruptly that is caused by the over-voltage at the time of turn-on and turn-off. In this paper, as for voltage resonant type of push-pull high-frequency inverter circuit, a control method using a short-circuit mode actively that turns 2 switches on at the same time in power output control is proposed and the theoretical analysis and practical experiments are carried out. Then, the application of the control method to electric-discharge lamp is studied. As for the comparison of the steady-state characteristics of theoretical analysis with the experiment data, the result shows the both agrees well with each other even though there are some errors caused by the parasitic capacity of the MOSFET being a switch of the circuit. And, a stable output control in a wide range is achieved based on the experiments of the lighting circuit of the electric-discharge lamp. 7 refs., 7 figs., 3 tabs.

  12. Assessing the Feasibility of In-Situ Aerobic Cometabolism of Chlorinated Solvents by a Single-Well Push-Pull and Natural Gradient Drift Tests in McClellan AFB, CA

    Science.gov (United States)

    Kim, Y.; Istok, J. D.; Semprini, L.

    2001-12-01

    A single-well push-pull test has been developed to evaluate in-situ aerobic cometabolic treatment of chlorinated aliphatic hydrocarbons (CAHs), such as trichloroethylene (TCE) and cis-1,2-dichloroethylene (c-DCE). A series of single-well natural gradient drift and push-pull tests were conducted in two monitoring wells at the McClellan Air Force Base, CA, where aquifer is contaminated mainly with c-DCE and TCE. Transport characteristics of dissolved solutes [bromide (tracer), propane (growth substrate), ethylene, propylene (nontoxic surrogates to probe for CAH transformation activity), DO and nitrate (nutrient)] were evaluated in push-pull transport tests by injecting 200-L of groundwater containing the solutes into the aquifer (Push), providing a rest period of 18 hours (Reaction), and then extracting 400-L of the test solution/groundwater mixtures (Pull). Mass balances showed over 95% of the injected bromide was recovered, and the recoveries of the other solutes were comparable with bromide. The dispersion of all the solutes was similar indicating sorption or other partitioning processes were minimal. These results indicate that bromide could be used as a conservative tracer for biological activity tests and that little loss of the dissolved gaseous substrates occurred prior to biostimulation of the aquifer. A series of biostimulation tests were performed by injecting 500 L-groundwater containing propane (6 mg/L), DO (25 mg/L), nitrate (9 mg/L as N) and bromide (100 mg/L) into the aquifer. Temporal groundwater samples were obtained from the injection well under natural gradient drift conditions. With repeating biostimulation tests the rates of both propane and DO utilization were increased significantly. The results demonstrated that the progress of biostimulation could be assessed by injecting and monitoring under natural gradient drift conditions. Successive push-pull activity tests were performed after biostimulation was achieved using the same procedures as

  13. 单电感电流连续型推挽类拓扑的推衍和特性研究%Derivation and Characterization of Single-inductor Push-pull Based Topologies With Continuous Currents

    Institute of Scientific and Technical Information of China (English)

    陈骞; 郑琼林; 李艳

    2013-01-01

    In view of the widely applications of push-pull based converters in aircraft power supply and the superiority of the topology with continuous input and output currents, this paper proposed a concept of single-inductor push-pull based topologies with continuous input and output currents. Four new kinds of non-isolated push-pull cells are deduced from traditional push-pull cells. The circuit configurations based on these four kinds of push-pull cells are also derived, three of them are firstly proposed. These topologies can be divided into the Smart type and the Weinberg type according to topology structures and control methods. Sags exist in the low ripple current of the Smart topology and spikes exist in that of the Weinberg topology, while the problem isn't exist in proposed topologies. The push-pull-based topologies can be used for battery discharge regulators (BDR) or battery charge regulators (BCR) based on the condition that the bus current should be of low-ripple. The advantages and disadvantages of topologies are achieved by comparing characteristics, which can provide a theoretical support for DC-DC converters used in PCU. In addition, the experimental results based on one of the proposed topologies are given to verify the validity of theoretical analysis.%鉴于电流连续型拓扑的优越性,结合推挽类拓扑在卫星电源系统中应用广泛的现状,提出单电感电流连续型推挽类拓扑的概念.通过对传统推挽单元进行推导得到4种新的非隔离型推挽单元.以此为基础,分别推衍得到4类推挽单元的单电感电流连续型拓扑族,其中有3种拓扑为首次提出的新型拓扑.根据拓扑结构以及控制方式的不同,可将这些拓扑分成Smart和Weinberg两类,其中Smart类拓扑低纹波侧电流存在凹陷,已提出的Weinberg类拓扑低纹波侧电流存在尖峰,而该文提出的3种新型拓扑不存在此问题.由母线侧电流低纹波的条件,还可将所有拓扑分成适用作蓄

  14. Evaluation of a Push-Pull Approach for Aedes aegypti (L.) Using a Novel Dispensing System for Spatial Repellents in the Laboratory and in a Semi-Field Environment.

    Science.gov (United States)

    Obermayr, Ulla; Ruther, Joachim; Bernier, Ulrich R; Rose, Andreas; Geier, Martin

    2015-01-01

    The increase in insecticide resistant mosquito populations necessitates the exploration of novel vector control intervention measures. Push-pull strategies for insect control have been successful when used in integrated crop pest management. Through the combinatory use of deterring and attracting stimuli, the abundance of insect pests can be changed in a given area. A push-pull strategy might also significantly reduce human-vector contacts and augment existing mosquito control strategies, e.g. through the combination of an attractive trapping system and a potent spatial repellent. Our approach includes the BG-Sentinel (BGS) trap in combination with catnip oil (Nepeta cataria), a known spatial repellent for Aedes aegypti. To impart a deterrent effect on mosquitoes at a distance, a homogenous and continuous dispersal of volatile repellent compounds is crucial. We have developed a repellent dispensing system that is easy to use and provides a homogenous dispersal of repellent in an air curtain. The use of five 9 V fans and custom-made repellent sachets containing 10% catnip essential oil created a repellent loaded air curtain that provided coverage of an area of 2 m2 (1.2 x 1.65 m). Air was sampled at four different heights in the curtain and analysed via thermal desorption (TD) and consecutive gas chromatography-mass spectrometry (GC-MS). Nepetalactone, the main constituent of the oil, was detected in air at a concentration range of 80 to 100 μg/m3 and the amounts were comparable at all four sampling positions. When a human volunteer was sitting behind the repellent curtain and a BGS trap was installed in front of the curtain in laboratory push-pull trials, Ae. aegypti landing collections decreased significantly by 50% compared to repellent-free controls. However, in a semi-field environment, comparable protective effects could not be achieved and further research on suitable repellent concentrations for outdoor implementation will be required.

  15. Evaluation of a Push-Pull Approach for Aedes aegypti (L. Using a Novel Dispensing System for Spatial Repellents in the Laboratory and in a Semi-Field Environment.

    Directory of Open Access Journals (Sweden)

    Ulla Obermayr

    Full Text Available The increase in insecticide resistant mosquito populations necessitates the exploration of novel vector control intervention measures. Push-pull strategies for insect control have been successful when used in integrated crop pest management. Through the combinatory use of deterring and attracting stimuli, the abundance of insect pests can be changed in a given area. A push-pull strategy might also significantly reduce human-vector contacts and augment existing mosquito control strategies, e.g. through the combination of an attractive trapping system and a potent spatial repellent. Our approach includes the BG-Sentinel (BGS trap in combination with catnip oil (Nepeta cataria, a known spatial repellent for Aedes aegypti. To impart a deterrent effect on mosquitoes at a distance, a homogenous and continuous dispersal of volatile repellent compounds is crucial. We have developed a repellent dispensing system that is easy to use and provides a homogenous dispersal of repellent in an air curtain. The use of five 9 V fans and custom-made repellent sachets containing 10% catnip essential oil created a repellent loaded air curtain that provided coverage of an area of 2 m2 (1.2 x 1.65 m. Air was sampled at four different heights in the curtain and analysed via thermal desorption (TD and consecutive gas chromatography-mass spectrometry (GC-MS. Nepetalactone, the main constituent of the oil, was detected in air at a concentration range of 80 to 100 μg/m3 and the amounts were comparable at all four sampling positions. When a human volunteer was sitting behind the repellent curtain and a BGS trap was installed in front of the curtain in laboratory push-pull trials, Ae. aegypti landing collections decreased significantly by 50% compared to repellent-free controls. However, in a semi-field environment, comparable protective effects could not be achieved and further research on suitable repellent concentrations for outdoor implementation will be required.

  16. 一种新型软开关推挽三电平直流变换器%A NEW SOFT-SWITCHING PUSH-PULL THREE-LEVEL CONVERTER

    Institute of Scientific and Technical Information of China (English)

    马运东; 阮新波; 严仰光

    2002-01-01

    The application areas of conventional push-pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero-voltage and zero-current-switching (ZCS) PWM push-pull three-level converter in which the voltage stress of switches is input voltage. With phase-shifted modulation strategy, the leading switches can only realize zero-voltage-switching (ZVS), and the lagging switches can realize ZCS when block capacitor and block diodes are added. Using the strategy, the converter overcomes the drawbacks presented by the conventional push-pull converter, such as magnetic aberration, large switch loss, and voltage spike on switches, so it can get higher efficiency, and a wider application area. The operating principle of the new converter is analyzed and verified on a 600 W, 50 kHz experimental prototype. Several zero-voltage and zero-current-switching PWM push-pull three-level converters are proposed.%由于传统推挽直流变换器中开关管的电压应力高(输入电压的两倍),故该变换器的应用范围受到限制.本文提出了一种新型的零电压零电流开关PWM推挽三电平直流变换器,其中开关管的电压应力为输入电压.对该变换器采用移相控制,可以发现超前管只能实现零电压开关;加入阻断电容和阻断二极管可以使滞后管实现零电流开关.在这种控制方式下该变换器克服了传统推挽变换器存在的偏磁现象、开关损耗大、开关管有电压尖峰等缺点,使得其变换效率更高,有更广的应用范围.该变换器的工作原理在一个600 W,50 kHz的实验样机上得以分析和验证.最后,本文还提出了另外几种零电压零电流开关PWM推挽三电平直流变换器.

  17. 安徽省农民工市民化推拉力效果分析%The Push - pull Analysis of Urbanization of the Migrant Rural Workers of Anhui Province

    Institute of Scientific and Technical Information of China (English)

    饶亚会

    2014-01-01

    Urbanization of migrant workers is an important part of the deep urbanization. Establishing a mod-el about urbanization of the migrant rural workers regarding push,pull and friction to analyze the factors’elastic-ity with 1981 - 2012 relevant data of Anhui based on the push - pull migration theory. The preliminary study in-dicates that the maximum elasticity is pull,push is the second and the minimum elasticity is friction. Further stud-y show that the motive power of urbanization of the migrant rural workers mainly comes from the development of industrialization and urbanization,and the low level of agricultural modernization and institutional change hinder the development of industrialization and urbanization. What’s more,the urban - rural dual structure negates the effects of the traditional push - pull effort.%农民工市民化是深度城市化的重要组成部分,以人口迁移推拉理论为基础,建立了推动力、摩擦力和吸拉力对农民工市民化作用效果模型。根据安徽省1981-2012年相关数据,分析了农民工市民化影响因素的弹性系数,发现吸拉力弹性系数最大,推动力次之,摩擦力最小。进一步研究发现,农民工市民化动力主要来自工业化和城市化发展,而农业现代化整体水平不高和制度变迁缓慢一定程度上阻碍了农民工市民化进程,城乡严重对立的二元经济社会结构使得传统推拉力失效。

  18. In vivo monitoring of quantum dots in the extracellular space using push-pull perfusion sampling, online in-tube solid phase extraction, and inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Su, C K; Huang, C W; Yang, C S; Wang, Y J; Sun, Y C

    2010-09-01

    To monitor the dynamic changes of extracellular quantum dots (QDs) in vivo in the livers of anesthetized rats, we developed an automatic online analytical system comprising push-pull perfusion (PPP) sampling, the established in-tube solid phase extraction (SPE) procedure, and inductively coupled plasma mass spectrometry (ICPMS). The method takes advantage of the retention of QDs onto the interior surface of a polytetrafluoroethylene (PTFE) tube as a means of extracting the QDs from complicated push-pull perfusates. For the injected QDs present in the liver extracellular fluid (ECF) at low picomolar levels, a temporal resolution of 10 min was required to collect sufficient amounts of QDs to meet the sensitivity requirements of the ICPMS system. To the best of our knowledge, this study is the first to exploit the PPP technique for the collection of QDs from living animals and PTFE tubing as a SPE adsorbent for the online extraction of QDs and the removal of biological matrix prior to ICPMS analysis of cadmium-containing inorganic nanocrystal. We confirmed the analytical reliability of this method from measurements of the spike recoveries of saline samples; in addition, we demonstrated the systems' applicability through in vivo monitoring of the time-dependent concentration profile of liver extracellular QDs in living rats after intravenous administration.

  19. 推挽型光伏并网微逆变器控制策略研究%Research on Control Strategy of Push-Pull Micro-Inverter in Photovoltaic Grid-Connected Applications

    Institute of Scientific and Technical Information of China (English)

    刘芳; 赖良发; 苏建徽

    2012-01-01

    根据推挽型光伏并网微逆变器的拓扑结构特点提出了一种适合该拓扑的控制策略,详细分析了该控制策略的原理,推导了该控制策略下并网电流与其参考信号之间的约束关系,借助MATLAB仿真软件验证了控制策略的可行性.该控制策略使推挽型光伏并网微逆变器工作于电流源模式下,具有较高的并网电流质量.%By analyzing the topology of the push - pull micro - inverter for grid - connected PV, a new control strategy of the inverter is proposed. The control strategy is then analyzed in detail. The relationship between the grid - connected current and its reference signal are derived simultaneously. Furthermore, a MATLAB -based circuit is built to verify the feasibility of the proposed control strategy. It is shown through simulation results that as the push - pull micro - inverter operates in current source mode, it may have higher quality of the grid - connected current in a great degree.

  20. A two-step strategy to design high bioavailable controlled-release nimodipine tablets: the push-pull osmotic pump in combination with the micronization/solid dispersion techniques.

    Science.gov (United States)

    Liu, Xiaohong; Wang, Shang; Chai, Liqing; Zhang, Dong; Sun, Yinghua; Xu, Lu; Sun, Jin

    2014-01-30

    In order to decrease the fluctuation of blood concentration and to increase the oral bioavailability of nimodipine (NMD), a two-step strategy including the push-pull osmotic pump (PPOP) method in combination with micronization and solid dispersion techniques, was used to prepare the controlled-release high-bioavailability solid dosages. The optimization of formulation and process was conducted by comparing effects of different solubilization methods on release behavior of NMD. The in vitro dissolution studies indicated that both the two strategies were able to deliver NMD in the predetermined zero-order manner from 2 to 12h, regardless of effects of release media and agitation rates. Although the Cmax values of two PPOP tablets were lower than that of the reference formulation, both the Tmax values were prolonged, demonstrating the prominent controlled release performance. In comparison with the commercial reference tables, the relative bioavailability of the two formulations was 67.0% and 121.1%, respectively, indicating the solid dispersion technique was more efficient than the micronization technique in terms of solubilization capability and absorption enhancement. In summary, the two-step strategy, combining the push-pull osmotic pump method with the solid dispersion technique, is a very effective method to prepare high bioavailable controlled-release formulations of the poorly soluble drugs, i.e. NMD, taking into account the therapeutical efficiency and safety.

  1. Quantification of the push-pull effect in substituted alkynes. Evaluation of +/-I/+/-M substituent effects in terms of C[triple bond]C bond length variation.

    Science.gov (United States)

    Kleinpeter, Erich; Frank, Andrea

    2009-06-18

    (13)C chemical shifts of alkynes, published to date, were computed at the DFT (B3LYP/6-311G*) level of theory and compared with the experimental delta values, and the agreement was employed as a measure of quality for the underlying structures. For the corresponding global minima structures, thus obtained, the occupation quotients of antibonding pi* and bonding pi orbitals (pi*(C[triple bond]C)/pi(C[triple bond]C)) and the bond lengths (d(C[triple bond]C)) of the central C[triple bond]C triple bond were computed and correlated to each other. The linear dependence obtained for the two push-pull parameters d(C[triple bond]C) and pi*(C[triple bond]C)/pi(C[triple bond]C) quantifies changes in the push-pull effect of substituents while deviations from the best line of fit indicate and ascertain quantitatively to what extend the inductive (+/-I) substituent effect changes with respect to the bond length of the C[triple bond]C triple bond.

  2. Intriguing Influence of -COOH-Driven Intermolecular Aggregation and Acid-Base Interactions with N,N-Dimethylformamide on the Second-Order Nonlinear-Optical Response of 5,15 Push-Pull Diarylzinc(II) Porphyrinates.

    Science.gov (United States)

    Orbelli Biroli, Alessio; Tessore, Francesca; Righetto, Stefania; Forni, Alessandra; Macchioni, Alceo; Rocchigiani, Luca; Pizzotti, Maddalena; Di Carlo, Gabriele

    2017-06-05

    A series of 5,15 push-pull meso-diarylzinc(II) porphyrinates, carrying one or two -COOH or -COOCH3 acceptor groups and a -OCH3 or a -N(CH3)2 donor group, show in N,N-dimethylformamide and CHCl3 solutions a negative and solvent-dependent second-order nonlinear-optical (NLO) response measured by the electric-field-induced second-harmonic generation (EFISH) technique, different from the structurally related zinc(II) porphyrinate carrying a -N(CH3)2 donor group and a -NO2 acceptor group, where a still solvent-dependent but positive EFISH second-order response was previously reported. Moreover, when a -N(CH3)2 donor group and a -COOH acceptor group are part of a sterically hindered 2,12 push-pull β-pyrrolic-substituted tetraarylzinc(II) porphyrinate, the EFISH response is positive and solvent-independent. In order to rationalize these rather intriguing series of observations, EFISH measurements have been integrated by electronic absorption and IR spectroscopic investigations and by density functional theory (DFT) and coupled-perturbed DFT theoretical and (1)H pulsed-gradient spin-echo NMR investigations, which prompt that the significant concentration effects and the strong influence of the solvent nature on the NLO response are originated by a complex whole of different aggregation processes induced by the -COOH group.

  3. Surface-enhanced fluorescence and surface-enhanced Raman scattering of push-pull molecules: sulfur-functionalized 4-amino-7-nitrobenzofurazan adsorbed on Ag and Au nanostructured substrates.

    Science.gov (United States)

    Muniz-Miranda, Maurizio; Del Rosso, Tommaso; Giorgetti, Emilia; Margheri, Giancarlo; Ghini, Giacomo; Cicchi, Stefano

    2011-04-01

    We investigated the chemisorption of self-assembled monolayers of sulfur-functionalized 4-amino-7-nitrobenzofurazan on gold and silver nanoisland films (NIFs) by means of surface-enhanced fluorescence (SEF) and surface-enhanced Raman scattering (SERS). The ligand is a push-pull molecule, where an intramolecular charge transfer occurs between an electron-donor and an electron-acceptor group, thus exhibiting nonlinear optical properties that are related to both SERS and SEF effects. The presence of different heteroatoms in the molecule ensures the possibility of chemical interaction with both silver and gold substrates. The SERS spectra suggest that furazan is bound to silver via lone pairs of the nitrogen atoms, whereas the ligand is linked to gold via a sulfur atom. Silver NIFs provide more efficient enhancement of both fluorescence and Raman scattering in comparison with gold NIFs. The present SEF and SERS investigation could provide useful information for foreseeing changes in the nonlinear responses of this push-pull molecule.

  4. TWO-ARMED PUSH-PULL SINGLE-PHASE VOLTAGE SOURCE INVERTERS AND THEIR MODULATION SCHEME%双臂推挽式单相电压源逆变器及其调制方案

    Institute of Scientific and Technical Information of China (English)

    谷春艳; 刘超英

    2004-01-01

    该文介绍了一种双臂推挽式逆变器,包括其电路拓扑、每个开关器件的功率分布和调制策略.分析了这种电压源逆变器的主要参数,如总谐波失真度(THD)和失真指数(DF).比较研究表明,这种逆变器的质量明显优于方波逆变器,同时开关损耗明显低于PWM调制方式,特别适用于宽频范围.介绍了计算公式和实验结果.%This paper proposes a two-armed push-pull inverter,including its topologies,power distributions in every switching devices and modulation schemes.The major parameters such as THD and DF of this VSI are analyzed.Comparison study shows that the quality of two-armed push-pull VSI is better than those of square-wave VSI.And the switching loss is lower than that of PWM scheme at same time,especially used in wide frequency range.Detailed calculating formulae and experimental results are presented.

  5. Tai businessman investing in mainland development research under "push pull theory"%“推拉理论”视阈下台商大陆投资发展研究

    Institute of Scientific and Technical Information of China (English)

    肖冬华

    2012-01-01

    This thesis is a systematic research about Taiwanese investment in the mainland of China,which is on the basis of the push and pull theory.The push from Taiwan and the pull from the mainland of China strengthen gradually,which promote Taiwanese investment to increase a lot in the mainland of China.Especially,Taiwanese investment in agriculture grows rapidly.As well,Taiwanese investment in central China and in western China grows rapidly.Thus,facing the change in the situation of Taiwanese investment in the mainland of China,we should look forward to the rapid development of Taiwanese investment.And we should try to strengthen the push from Taiwan and the pull from the mainland of China,especially the pull.We should try to carry forward some rational industry policies and some rational region policies,in order to promote Taiwanese investment to boom and to create a new situation of Taiwanese investment in the mainland of China.%"推拉理论"为台商投资向大陆地区转移的动力分析提供了一个可参考的框架。在台湾"推力"和大陆"拉力"的作用下,我国台商大陆投资升温。在产业选择上,随着台商投资形势的不断发展,越来越多的台商选择在大陆投资农业,以农业为主的绿色投资升温。在区域选择上,中西部地区成为台商新的投资热点。面对新的形势,应借助台湾"推力",强化大陆"拉力",促进我国台商大陆投资掀起新的高潮。

  6. Research on Tourism Motivation of Domestic Tourists in Xiamen on Push-Pull Theory%基于“推-拉”理论的厦门国内滨海旅游者动机研究

    Institute of Scientific and Technical Information of China (English)

    郑木香; 郑耀星

    2015-01-01

    The paper makes a study of travel motiva tion of domestic coastal tourists in Xiamen and obtains first-hand data through questionnaire survey and in-depth interviews based on “push-pull” theory. First,the paper identifies four push and three pull motivation factors obtained by using factor analysis. Among them,“leisure & experience” and “management & services” appear to be the most important push and pull motivation factors respectively. Second,the finding reveals that pull and push does not exist correlation. As the result,targeted suggestions were given for tourism marketing and tourism product development which aims at the further development of Xiamen coastal tourism.%在“推-拉”理论视角下,通过对厦门国内滨海旅游者的问卷调查和深入访谈获得的第一手数据,利用因子分析法萃取出4个推力因子和3个拉力因子;其中,“休闲与体验”和“管理与服务”分别是最重要的推力因子和拉力因子。另外运用皮尔逊相关分析法探析推拉因子相互之间的关系;研究结果表明拉力因子中的滨海旅游资源与推力因子中的情感交流与康体的相关性最高,而拉力因子中的基础设施与服务和推力因子中的新奇与知识不存在相关性。研究结合定性和定量分析法,使得结论更具说服力,以期对旅游企业的产品开发和市场营销具有一定的参考价值,对旅游动机理论研究有所丰富。

  7. Optimal Hybrid Push/Pull Control Strategies with Integration of Production Control and Marketing Decisions%生产控制与市场决策一体化的PUSH/PULL混合优化问题

    Institute of Scientific and Technical Information of China (English)

    华中生; 梁悦盈; 杨国梁

    2000-01-01

    文献[1~3]提出了运用马尔可夫决策模型研究了生产控制中的PUSH/PULL混合问题.本文通过在模型中引入市场需求与价格决策变量,研究在生产控制与市场决策一体化条件下,即以总收益为决策目标的最优PUSH/PULL混合策略问题.

  8. The use of push-pull strategy in medical pests integrated management%“推-拉策略”在医学昆虫综合治理中的应用

    Institute of Scientific and Technical Information of China (English)

    张瑞玲; 陈丹; 刘婧; 庄桂芬; 张忠

    2016-01-01

    害虫防治的“推-拉策略”是一种新兴的无害化害虫综合治理方法,主要采用天敌或其他手段驱避害虫与诱杀害虫相结合的方法,来达到消灭害虫的目的,同时该方法还可减少农药的使用,保护生态环境。虽然该策略在农业昆虫防治中已多有应用,但在医学昆虫防治中应用相对较少。有鉴于此,该文对“推-拉策略”在医学昆虫控制中的应用进行了综述,以推动医学昆虫治理方法的理念更新。%Push⁃pull strategy is a new integrated, nontoxic pest management method. The strategies involve the behavioral manipulation of insect pests and their natural enemies via the integration of stimuli that make the protected sources unattractive or unsuitable to the pests (push), while luring them toward attractive sources (pull) from where the pests are subsequently removed. The strategy is a useful tool for integrated pest management programs reducing pesticide application. The strategy has been successfully used in agriculture pest management. But in management of public health pests, it was only used in few species. In this paper, it summarized some cases of push⁃pull strategies used in public health pest control, in order to promote the push⁃pull application in the future.

  9. A Compensation Method for Deflection of Ram with Combined Pull and Push Rods%拉杆与推杆组合式滑枕挠曲变形补偿法

    Institute of Scientific and Technical Information of China (English)

    吴凤和; 赵峰兵

    2012-01-01

    According to structural and loading characteristics of ram of heavy - duty CNC boring and milling machine,a new compensation method for the deflection of the ram with combined pull and push rods was proposed. Based on eccentric compression(or tensile) theory,two group of rods which provided opposite direction forces were installed inside of the ram. One group was the pull rods installed on the top side of the ram,another group was the push rods installed on the bottom side of the ram. Two group of pull and push rods were arranged with up and down,left and right symmetry about the spindle centerline,which form the two -way force groups. The axial pitch of two push rods and two pull rods were equal in size and opposite in direction, so there were no additional deformation in axial direction. Compared with the traditional compensation method with pull rods, the compensation forces were provided by two tension cylinders and two thrust cylinders, so in the situation of same compensation degree,only a smaller cylinder pressure needed to be provided. The advantages of this compensation method were verified by theoretical analysis and finite element simulation.%针对重型数控落地铣镗床的滑枕结构及受力特点,提出一种新型的滑枕挠曲变形补偿方法——拉杆与推杆组合式补偿法.依据偏心压缩(拉伸)理论,在滑枕内部设置两组作用力方向相反的杆件:一组为置于滑枕上半侧的拉杆,另一组为置于滑枕下半侧的推杆.两根拉杆和两根推杆沿主轴中心线呈左右和上下对称布置,形成双向作用力组.由于拉杆与推杆在滑枕轴向的作用效果相互抵消,该方法在补偿滑枕的挠曲变形时不会产生附加的轴向变形.与传统的拉杆补偿法相比,该方法采用拉力和推力两组油缸提供补偿挠曲变形的驱动力,在补偿相同挠度的情况下,油缸所需提供的压力较小.通过理论分析与有限元仿真对该方法的优点进行了验证.

  10. Research on Parents-Child Tour Decisions Based on“Push-Pull-Obstruction” Theory%基于“推拉阻”模型的国内亲子旅游决策研究

    Institute of Scientific and Technical Information of China (English)

    刘妍; 赵川; 陈嘉睿

    2016-01-01

    Based on the “push-pull” theory,“push-pull-obstruction” theory has been proposed and applied in the parents-child tour (PCT) decision.According to 319 valid questionnaires, push, pull and obstruction suc-cessively were the important influence factors to PCT decision by SPSS 21.0.Factor Analysis has obtained 2 push factors (child-oriented and parents-oriented), 4 pull factors(perfect facilities, excellent environment, special serv-ice and distinctive theme ) and 2 obstruction factors ( children factor , time and expenditure factor ) .Enhancing the parents-child ’ s relationship , relaxed and pleasant tour itinerary , insufficient holiday are the most important factors for the push , pull and obstruction respectively .ANOVA has made the conclusion that there are some significant cor-relativity between the demographic variables and PCT decision , such as the number and ages of kids , parents’ ed-ucational background .%亲子旅游是国内近年来迅速升温的旅游形式,但国内对该领域的研究非常匮乏。基于“推拉”动机理论,构建“推拉阻”模型应用于亲子旅游决策研究。采用SPSS 21.0对319份有效问卷进行统计,亲子旅游决策的影响因素按照重要性依次是推力、拉力和阻力。通过因子分析得到2项推力动机(“孩子主导型”和“家长主导型”)、4项拉力动机(“设施完善”“环境优良”“特色服务”和“主题鲜明”)、2项阻力因子(“小孩因子”和“时间与费用因子”)。其中,“增加亲子感情”“旅游行程安排轻松愉快”和“家长没有足够的闲暇时间”分别是最重要的推力、拉力和阻力变量。单因素方差分析显示,小孩数量与阻力的“小孩因子”呈显著正相关,小孩年龄与拉力动机的“环境优良”存在显著的正相关,家长学历对推力动机的“家长主导型”和拉力动机的“环境优良”均产生显著影响。

  11. Single-Primary-Winding Voltage-Fed Double-Input Push-Pull Converter%单原边绕组电压源型双输入推挽变换器

    Institute of Scientific and Technical Information of China (English)

    徐原; 王勤; 肖岚; 郁超

    2011-01-01

    多原边绕组多输入推挽变换器适用于中小功率场合,但随着输入源数量的增加,原边绕组和开关管的数量均增多。论文根据脉冲电压源组合原则,将非隔离型脉冲电压源串联或并联的组合直接替代单输入推挽变换器的输入源.从而获得一族单原边绕组电压源型多输入推挽变换器。相对于传统的多原边绕组多输入推挽变换器,它具有单个原边绕组,因此体积和成本将大为减小。文中以Buck型脉冲电压源串联组合构成的单元边绕组双输入推挽变换器为例.详细分析其工作原理、模态和性能,并阐述控制原则,最后给出仿真及实验结果以验证理论分析的正确性。%Multi-input push-pull converter with multiple-primary-winding is suitable in small and medium-power applications. However, with the increase of the input sources, the number of the primary windings and switches increases as well. Based on Pulsating Voltage Source Cells (PVSCs) combination principle, the input voltage source of the single-input push-pull converter is replaced with the series or parallel-cormected non-isolated pulsating voltage source cells (PVSCs). So a family of single- primary-winding (SPW) voltage-fed multi-input push-pull converters can be proposed. Compared to traditional multi-input converters, they have a form of single-Primary-Winding, and therefore the size and cost is greatly reduced. Since the configuration of a double-input Buck DC/DC converter is very simple, it is chosen as an example to analysis the MIC. The operation principle, modes and control strategy are illustrated. Finally, simulation and experimental results are presented to verify the theoretical analysis.

  12. Progressive DVE Prefetching Mechanism Using Social Recommendation and Pull-Push Strategy%结合社交推荐和推拉策略的渐进式DVE预下载机制

    Institute of Scientific and Technical Information of China (English)

    王明飞; 范辰; 贾金原

    2015-01-01

    为了提高基于对等网络的分布式虚拟环境(DVE)场景预下载的预测精度并降低场景数据传输延迟,将社交推荐和推拉混合策略应用到DVE场景预下载中。首先描述和量化节点化身在虚拟环境中的兴趣,并对化身间相似度进行计算,生成预推荐场景集;然后将化身的视野区域划分为预拉取和预推送区域,提出针对不同区域预下载的推拉策略。基于开源 DVE 平台 FLoD 进行的实验结果表明,该机制能提高场景的预测精度并减少信息交互次数,进而提升DVE场景传输效率和化身漫游流畅度。%In order to improve prediction precision of the scene prefetching and reduce the scene transmis-sion latency in the distributed virtual environment (DVE) based peer to peer network, we propose an effi-cient progressive prefetching mechanism, which combines the social recommendation with different Pull-Push strategies. First, we describe and quantify the avatar interests in the virtual environment to obtain the interest similarity between avatars and generate pre-recommend scene set. Then, we divide the avatar viewing area into the pull area and the push area, and provide different Pull-Push strategies for prefetching the scene in different area. Finally, we demonstrate the proposed prefetching mechanism using an open-source DVE platform called FLoD. Experiment results show that our approach improves the scene prediction precision, reduces the information exchange, and promotes the scene transmission efficiency and avatar roaming fluency.

  13. 3D numerical simulation of the flow field with push-pull hoods containing barriers between them%罩间存在障碍物的吹吸罩流场三维数值模拟

    Institute of Scientific and Technical Information of China (English)

    胡鸿; 易灿南; 廖可兵

    2013-01-01

    为了使吹吸罩达到对污染物的最佳控制,以某企业电镀生产线上行车行进过程中由于镀件表面黏附高浓度槽液而造成室内环境污染为实物模型,建立吹吸罩口间存在障碍物的三维数学模型,利用Fluent计算动力学软件对不同吹风口风速和吸风口风速下的排风罩流场进行数值模拟,经比较确定最佳联合速度,并将模拟结果与经典吹吸速度分布图及试验条件下所测得的污染气体质量分数进行对比分析.结果表明,所建立数学模型是合理的,所确定的最佳效果时的相关参数与经典理论基本一致,可用于工程实际.%This paper attempts to proposo a 3D numerical simulation model of the flow field with push-pull hoods containing barriers between them in hoping to solve the problem of the dispersion of contaminants.As is known,the dispersion of contaminants in different sections of an apparatus can be controlled effectively via a pull-push hood powered by a jet flow.Actually,such device has already been widely used in places where contaminants are serious but can not be eliminated.The said push-pullhoods are usually armed with the following features:minute air volume,perfect pollution control,powerful anti-jam behavior,free from the impact of the process operations.Although no barriers were considered in the former design between the push hood and pull hood in the regular production process according to the processing demands,we still feel it necessary to stress the demand for them,for it is necessary to choose the best velocity of push hood and pull hood to control the containments.Based on the above starting point,we have chosen the computational fluid dynamics (CFD) model to solve the problem.First of all,we have taken the contaminants accumulated in the painted work-pieces with very harmful content adhered in them as a physical model,while assuming that geometrical models are set by the GAMBIT code.Along with it,let the appropriate

  14. Simulation-Based Optimization on RFID-Enabled Push/Pull Control Strategy for Supply Chain%供应链库存的RFID使能的Push/Pull控制策略优化

    Institute of Scientific and Technical Information of China (English)

    李国家; 汪定伟

    2015-01-01

    射频识别(RFID)技术的产生为供应链多级库存性能的改善提供了新的方法.基于RFID技术借鉴单工厂多阶段生产存储系统的Push/Pull策略,以供应链分销网络三级库存系统为例设计了8种RFID使能的Push/Pull混合控制策略.为得到各策略的更优性能,采用基于仿真的粒子群优化方法对各策略参数进行了优化,验证了基于仿真的粒子群优化算法对优化RFID使能的Push/Pull混合控制策略的可行性和有效性,优化后各策略的仿真结果表明8种混合策略中制造商阶段采用Push控制,分销商和零售商阶段采用Pull控制的策略性能最优.

  15. A Study on Push and Pull Price Promotion with Deterministic Effects%基于确定性效应的推式和拉式价格促销研究

    Institute of Scientific and Technical Information of China (English)

    梁冬寒; 李刚; 孙林岩

    2012-01-01

    This paper focuses on the performances of the pull and push promotions in seasonal product sales. We study the pull and push promtion through a Manufacturer-led Stackelberg game, on the basis of the different impacts of the two types of price promotion on the market demand. By solving the equilibrium strategies of the manufacturer and the retailer, we find that the pull and push promotion are substituable with deterministic price effects. In other words, deterministic price effects do not demonstrate the main difference the pull and push promotion. Moreover, the paper suggests that price promotion neither significantly changes the original profit-spliting policy nor benefits the retailer. Finally, the analysis reveals that complete demand information enables the manufacturer to distiguish between the quantities sold in the regular period from those in the promotional period, so the retailer would not be over compensated and the pass-through rate exceeds 100 percent.%针对推式促销和拉式促销在季节性商品销售中的作用绩效问题,基于推式促销和拉式促销对需求曲线的不同影响机制,本文构建了制造商领导的Stackelberg博弈模型,求解制造商和零售商在正价销售期和促销期各自的均衡策略.通过分析和比较两种价格促销方式的效率和性质,发现对于确定性的价格效应,推式促销和拉式促销是可完全替代的,因而确定性的价格效应并不能解释二者的差异.本文进一步研究了实施价格促销前后供应链上下游间的利润分配格局,发现制造商获得了大部分利润,高于零售商获得的利润,而且实施价格促销并不能显著的改变供应链的利润分配格局.最后,通过分析推式促销的性质,指出完善的需求信息有利于制造商分辨正价销售期和促销期的需求,避免过度补偿零售商,从而部分解释了供应链的价格传递效应高于1的现象.

  16. A Strategy of Push-and-Pull Material Distribution in Complex Assembling Workshop%复杂装配车间的物料推拉式配送策略

    Institute of Scientific and Technical Information of China (English)

    张轶伦; 梁鹏迪; 许健; 裴东浩

    2014-01-01

    主要针对复杂装配车间的物料配送过程中出现的物料积压、配送模式单一、配送效率低等现象提出了一套推拉式结合的配送策略。这套配送策略包含推式配送管理策略和与之相对应的库存盘点策略,以及一种配送提前期算法;此外,在拉式配送策略方面还提出了最晚起配时间和处理周期两个关键理念,并对临时急需、返工等突发情况的处理提出了优化建议,较好的保证了生产和配送过程的稳定性。%A strategy of push-and -pull material distribution is proposed in the paper,which is concerned to solve the overstock of materials,the homo-style and low efficiency problem in the complex assembling workshop. The overall method includes the push-style distribution strategy with a discipline of the inventory examination and an algorithm to calculate the leading time. In addition,the paper also proposes two critical concepts in pull-style distribution:the latest delivery time and the process cycle time,which also provides some advice in case of the unexpected demand, re-assembling or other emergency circumstances in order to maintain the stability in the production process.

  17. Low Loss Passive Snubber in Push-pull Voltage Source Inverter%一种用于推挽式电压型逆变器的低损耗无源吸收电路

    Institute of Scientific and Technical Information of China (English)

    伍家驹; 杉本英彦

    2006-01-01

    A low loss passive snubber is developed for the PWM push-pull Voltage Source Inverter (VSI). In order to avoid the superposition of the high frequency discharge energy on the output voltage, an independent discharge circuit is introduced to feed back part of the energy in the capacitor to DC source. Due to the voltage clamp on the capacitor, there is,for the doubled voltage of the push-pull circuit, no additional loss in the snubber. Details of design and a 200V DC input,30kW VSI application example are also presented.Experimental results show that the circuit topology is a good choice in low loss snubber design.%提出并实现了一种推挽式PWM电压型逆变器用无源吸收电路;设有独立的放电回路让缓冲电容器上的能量部分地回馈到直流电源中,高频放电能量不会叠加在输出电压上;缓冲电容器的电压被钳位,使得推挽电路特有的倍压不会在吸收电路上造成额外的损耗.给出吸收电路参数的设计准则和计算实例,在200VDC和30kW级的中压中功率逆变装置中发挥了推挽拓扑的优点.理论分析和实验验证了所提方法的有效性.

  18. Study on the effect of leakage inductance in a push-pull converter%一种推挽式变换器的漏感影响研究

    Institute of Scientific and Technical Information of China (English)

    郑长明; 张加胜; 陈瑞; 朱辰星; 郑威

    2016-01-01

    According to the principle of magnetic potential balance , the operating waveforms and effects on perform-ance of the push-pull converter with bridge rectifier output circuit are analyzed .Combined with magnetizing induct-ance and leakage inductance effect of transformers , the equivalent circuit model and mathematical analytical model of the converters are established .The physical relationships and theoretical waveforms of push -pull converter with and without secondary side equivalent leakage inductance when the magnetizing inductance is placed between two primary windings of the transformer are discussed in detail .The effect of leakage inductance on terminal voltage of the switch , output voltage and energy feedback of the circuit and their elimination methods are deeply studied .The Matlab simula-tion verifies the correctness of the correlation model and theoretical results .%根据磁势平衡原理,研究了一种带桥式整流输出的推挽式变换器的工作波形及性能影响因素,主要结合变压器激磁电感和漏感效应,建立了变换器等效电路模型和数学解析模型,详细讨论了激磁电感跨接在变压器原边两绕组之间时,推挽变换器无漏感和漏感等效于副边侧时的物理关系和理论波形。深入分析了漏感对开关管端电压、电路输出电压和能量回馈等方面造成的影响及消除方法。通过Matlab仿真验证了有关模型及理论分析结果的正确性。

  19. 推式培训法在煤炭企业培训中的应用%Application of Push to Train in the Training of Coal Enterprises

    Institute of Scientific and Technical Information of China (English)

    汪莹; 王光岐

    2014-01-01

    在阐述推式培训法的内涵以及分析我国煤炭企业培训的现状与问题后,提出将推式培训法应用于煤炭企业培训。通过培训人员划分、培训需求分析、培训内容制作、培训实施,解释说明推式培训法在煤炭企业培训中具体应用流程。最后,总结了推式培训法在煤炭企业培训中具有的应用价值,包括合理解决了“工学矛盾”问题、培训内容更具针对性、增强员工培训的积极性、节约培训成本。%With the explanation of Push to Train and the analysis of the present situation and problems of coal enterprises training in our country , this paper puts forward the application of Push to Train in the training of coal enterprises .It illustrates the specific application process of Push to Train in the training of coal enterprises by division of personnel training , training needs analysis , training content making , training implementation . Finally, it summarizes the application value of Push to Train in the training of coal enterprises , including a reasonable solution to the “contradiction between working and learning” problem, more targeted training con-tent, enhancing staff training initiative , and saving training cost .

  20. Ensaios de arrancamento e de empuxamento aplicados a taliscas de bambu encravadas em corpos-de-prova de solo-cimento Pull-out and push-in tests of bamboo splint embedded in soil-cement specimen

    Directory of Open Access Journals (Sweden)

    Wilza G. R. Lopes

    2002-12-01

    Full Text Available Neste trabalho, taliscas de bambu da espécie Dendrocalamus giganteus, engastadas em corpos-de-prova de solo-cimento, foram submetidas a ensaios de arrancamento (pull-out e de empuxamento (push-out a fim de se determinar sua resistência de aderência. Para esta finalidade, foi utilizado um solo-cimento feito a partir de um solo arenoso que continha aproximadamente 70% de areia. Corpos-de-prova de solo-cimento, de 15 cm de diâmetro e 30 cm de altura, foram moldados com 14% de cimento na umidade ótima de 10,7%. As taliscas de bambu foram preparadas com 2 cm de largura e comprimentos de 40, 50 e 60 cm, para o ensaio de arrancamento, e de 70 cm para o ensaio de empuxamento. Metade das taliscas foi deixada sem tratamento impermeabilizante e a outra metade foi revestida com emulsão asfáltica, impregnada com areia limpa grossa, para produzir uma superfície áspera e garantir melhor aderência com o solo-cimento. Os corpos-de-prova de solo-cimento com as taliscas de bambu engastadas, foram deixados a curar em câmara úmida, durante 28 d, antes de serem ensaiados. Ambos os ensaios foram realizados em uma máquina universal de ensaio adaptada, sendo as deformações medidas com um relógio comparador aferido, de sensibilidade igual a 0,01 mm. A resistência de aderência, quer fosse determinada pelo ensaio de arrancamento quer pelo ensaio de empuxamento, foi obtida dividindo-se a máxima carga verificada no ensaio pela área lateral da talisca de bambu efetivamente engastada no solo-cimento. Os melhores resultados foram obtidos sem aplicação de material impermeabilizante, para o ensaio de arrancamento, enquanto nenhuma diferença foi observada entre os dois tratamentos para o ensaio de empuxamento.In this study, Dendrocalamus giganteus bamboo splints (split culm embedded in soil-cement specimens were submitted to pull-out and push-in tests in order to determine its bonding strength. For this purpose a sandy soil was utilized. The 15.0 cm diameter

  1. Using push-pull mode to achieve reputation system in P2P networks%P2P网络中利用推拉模式实现的信誉系统

    Institute of Scientific and Technical Information of China (English)

    秦志光; 杨毅; 杨磊; 钟婷

    2013-01-01

    In the existing reputation models, the accumulation of reputation of certain node requires so long a period even if that node provides good services, which influences the positivity of those newly added nodes. Besides, most models composite the global trust value by multiple iteration, and the huge amount of iteration will bring massive computational expense. On account of the above issue, this dissertation proposes a new reputation computing model by introducing the typical push-pull model in streaming media scheduling strategy. The push model can accelerate the trust value accumulation speed of those newly added nodes which provide good services, while the pull model reduces the network flows online and avoids the negative impacts of the iteration computation. Through analysis and simulation, this model can ensure the accuracy of reputation computation, meanwhile, the communication and computation expenses can get improved as well.%在现有的信誉模型中,即使节点积极提供良好的服务,节点信誉的累积也需要一个很长的周期,影响了新节点加入网络的积极性.此外,大部分模型在合成全局信誉值时采用多次迭代的方式,大量的迭代运算将导致巨大的计算开销.针对上述问题,通过引入流媒体调度策略中典型的推拉模式,提出一个新的信誉计算模型.在推模式下,对于那些新加入且积极提供优质服务的节点,可以加快其信誉累积速度,在拉模式下,减少了网络消息流量,避免了迭代计算的负面影响.分析及仿真表明,该模型在保证信誉计算准确性的同时,能较大程度改善通信及计算开销.

  2. Drawbar Pull

    Science.gov (United States)

    2017-01-26

    Includes procedures for hard surface, soil, and water tests. Discusses vehicle preparation, instrumentation method of computing results, data reduction...tracked vehicles on hard -surfaced roads, in soft soils, and of amphibious vehicles in water . b. Drawbar pull provides a measure of the reserve power...Drawbar Pull (Common).................................................. 5 4.2 Drawbar Pull on Hard Surface ......................................... 7

  3. Presence of two emissive minima in the lowest excited state of a push-pull cationic dye unequivocally proved by femtosecond up-conversion spectroscopy and vibronic quantum-mechanical computations.

    Science.gov (United States)

    Benassi, Enrico; Carlotti, Benedetta; Segado, Mireia; Cesaretti, Alessio; Spalletti, Anna; Elisei, Fausto; Barone, Vincenzo

    2015-05-14

    The long-standing controversy about the presence of two different emissive minima in the lowest excited state of the cationic push-pull dye o-(p-dimethylamino-styryl)-methylpyridinium (DASPMI) was definitively proved through the observation of dual emission, evidenced by both experimental (femtosecond up-conversion measurements) and theoretical (density functional theory calculations) approaches. From the fluorescence up-conversion data of DASPMI in water, the time resolved area normalized spectra (TRANES) were calculated, showing one isoemissive point and therefore revealing the presence of two distinct emissive minima of the excited state potential energy hypersurface with lifetimes of 0.51 and 4.8 ps. These spectroscopic techniques combined with proper data analysis allowed us to discriminate the sub-picosecond emitting state from the occurrence of ultrafast solvation dynamics and to disentangle the overlapping fluorescence (very close in energy) of the two components. Vibronic computations based on TD-DFT potential energy surfaces fully confirm those results and provide deeper insights about the key factors playing a role in determining the overall result. The two emissive minima have different structural and electronic characteristics: on one hand, the locally excited (LE) minimum has a flat geometry and an electric dipole moment smaller than the ground state; on the other hand, the twisted-intramolecular-charge-transfer (TICT) minimum shows a rotation of the methylpyridinium moiety with respect to the rest of the structure, and has an electric dipole moment significantly larger than the ground state.

  4. Theoretical investigation on redox-switchable second-order nonlinear optical responses of push-pull Cp*CoEt2C2B4H3-expanded (metallo)porphyrins.

    Science.gov (United States)

    Ma, Nana; Liu, Chunguang; Qiu, Yongqing; Sun, Shiling; Su, Zhongmin

    2012-01-15

    The second-order nonlinear optical (NLO) properties of the Cp*Co(C(2)H(5))(2)C(2)B(4)H(3)-expanded (metallo)porphyrins (Cp* = C(5)Me(5)) have been investigated by using ab inito RHF and density functional theory (DFT) methods. The investigation shows that the compound with expand porphyrin possesses remarkable large molecular hyperpolarizability β(tot) value, ~414.1 × 10(-30) esu (at LC-ωPBE level), and might be an excellent second-order NLO material. From the character of charge transfer (CT) transition, it indicates that the -Cp*Co(C(2)H(5))(2)C(2)B(4)H(3) acts as an electron donor in this kind of systems. As a result of the redox behavior on expanded (metallo)porphyrin, the redox switching character of the NLO responses for the systems 2a-4a has also been studied. The results show that the β(tot) values of reduced forms are larger than that of neutral ones. Furthermore, the time-dependent DFT calculation illustrates that reduced forms have a significant difference on the CT patterns versus neutral ones. The present investigation provides insight into the comparison with DFT results on estimating first hyperpolarizability and the NLO properties of the series of push-pull compounds. Copyright © 2011 Wiley Periodicals, Inc.

  5. The impact of the pi-electron conjugation on (15)N, (13)C and (1)H NMR chemical shifts in push-pull benzothiazolium salts. Experimental and theoretical study.

    Science.gov (United States)

    Hrobárik, Peter; Horváth, Branislav; Sigmundová, Ivica; Zahradník, Pavol; Malkina, Olga L

    2007-11-01

    The (15)N as well as (13)C and (1)H chemical shifts of eight push-pull benzothiazolium iodides with various pi-conjugated chains between dimethylamino group and benzothiazolium moiety have been determined by NMR spectroscopy at the natural-abundance level of all nuclei in DMSO-d(6) solution. In general, the quaternary benzothiazolium nitrogen is more shielded [delta((15)N-3) vary between - 241.3 and - 201.9 ppm] with respect to parent 3-methylbenzothiazolium iodide [delta((15)N-3) = - 183.8 ppm], depending on the length and constitution of the pi-conjugated bridge. A larger variation in (15)N chemical shifts is observed on dimethylamino nitrogen, which covers the range of - 323.3 to - 257.2 ppm. The effect of pi-conjugation degree has a less pronounced influence on (13)C and (1)H chemical shifts. Experimental data are interpreted by means of density functional theory (DFT) calculations. Reasonable agreement between theoretical and experimental (15)N NMR chemical shifts was found, particularly when performing calculations with hybrid exchange-correlation functionals. A better accord with experiment is achieved by utilizing a polarizable continuum model (PCM) along with an explicit treatment of hydrogen-bonding between the solute and the water present in dimethylsulfoxide (DMSO). Finally, (13)C and (1)H NMR spectra were computed and analysed in order to compare them with available experimental data. (c) 2007 John Wiley & Sons, Ltd.

  6. Research on Higher Education Recruitment of Overseas Students From the Perspective of Push-and-Pull Theory%推拉理论视角下我国高校留学生招生策略浅析

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    With the rapid increase of international student numbers in higher education section, some issues such as uneven distribution of specialties, unclear target of recruitment, and uncooperative between service and management are becoming more serious. Solutions to the issues mainly rely on the improvement of recruitment. This article tries to analyze the positive and negative factors influencing international students ’ decision to study in China from the perspective of Push-and-Pull Theory, aiming to make some contribution to the international students’ recruitment of higher education.%随着我国高校留学生招生人数的不断增加和教育规模的迅速扩大,招生目标不明确、专业选择分布不均、管理与服务关系不协调等问题日渐突出。解决这些问题有赖于我国高校留学生招生工作的进一步完善。利用推拉理论对来华留学的动机和阻碍因素进行分析,旨在保证留学生招生工作的可持续发展。

  7. 超声波电机推挽式驱动电源的设计制作%Development of the Push-pull Driving Circuit for Ultrasonic Motor

    Institute of Scientific and Technical Information of China (English)

    林星陵; 陈建毅

    2015-01-01

    The theory of ultrasonic motor and the mode of driving and control are different from traditional electromagnetic motor. In this paper, a simple driving circuit based on push-pull inverter for ultrasonic motor was fabricated according to the driving characteristic and requirement of the ultrasonic motor. The output of frequency, amplitude could be adjusted in a wide range. The experimental results indicate that the driving circuit with high reliability is suitable for ultrasonic motors driven by single-phase or two-phase signal.%超声波电机的工作原理及其驱动控制方式不同于传统的电磁电机。针对超声波电机的驱动特点和要求,本文运用推挽式逆变电路设计制作了一套简单实用的超声波驱动电源,该电源输出频率、输出电压都可在较宽的范围内调整。实际测试结果表明该电源性能稳定,能够满足两相或单相超声波电机的驱动要求,达到预期目标。

  8. Interpretation of single-well push-pull spikings conducted in deep crystalline formations (Soultz-s.-F. in the Upper Rhine Graben, and KTB-VB at the German site of ICDP)

    Science.gov (United States)

    Ghergut, J.; Sauter, M.; Behrens, H.; (Steffen) Fischer, S.; (Steffi) Fischer, S.; Licha, T.; Nottebohm, M.

    2009-04-01

    Two somewhat contrasting model approaches are presented, both aimed at interpreting long-term return signals from tracer push-pull tests conducted at single wells penetrating increased-permeability features in crystalline rock, about 4 km deep. The general idea is that single-well tracer push-pull tests, owing to the flow-field reversal, should provide privileged access to advection-independent parameters of solute transport, like the density of fluid-rock contact surface areas (Sauter et al., 2002). The latter is equivalent to the heat exchange area for a liquid-based geothermal system. At the geothermal site of Soultz-sous-Forêts in the Upper Rhine Graben, the French BRGM, in cooperation with EGI Utah and other partners, conducted a comprehensive tracer testing programme, whose results were presented in detail by Sanjuan et al. (2004, 2006), Rose et al. (2006). Of these results, we pick the tracer return signals detected during post-stimulation backflow periods at borehole GPK-2 between 2000 and 2002 (as published by Sanjuan et al., 2004) and attempt to interpret them in terms of a single-well injection-withdrawal sequence. Two chemically dissimilar organic tracers have been used by BRGM; however the difference between their return signals seems not significant enough to allow quantifying fluid-rock contact surfaces from this difference alone (additional / a priori information on coefficients of solute exchange across these surfaces would be required). Instead, the tracer return signals enable characterizing the nature of solute exchange processes within the spiked volume of the assumed fractured-porous formation (highly altered crystalline rock). At least one rapid-exchange (E-7 / d), slightly dispersive (Pe~12) component and one moderate-exchange (2E-8 / d), less dispersive (Pe~20) component appear to act within few hundred metres and, respectively, within at least 1 km radial distance from the borehole. - An alternative component of extremely fast exchange

  9. 基于“推拉理论”的海外高层次人才归国的适应性分析%The Study of Returning Adaptation of Overseas High-level Talents Based on the Push and Pull Theory

    Institute of Scientific and Technical Information of China (English)

    甄月桥; 朱茹华; 聂庆艳

    2013-01-01

      The scarcity of Overseas High-Level Talent makes their mobility more frequently all over the world. Based on the push-pull theory, The paper analyzed the causes of their mobility and the social adaptability Based on the push-pull theory.%  海外高层次人才的稀缺性导致他们在国际范围内流动较为频繁。本文以推拉理论为基础,详细解读海外高层次人才流动的原因,并对我国海外高层次人才的社会适应性进行分析。

  10. 推拉驱动模式供应链信息整合能力测度研究%Research on the Estimation of Push-Pull Driven Mode Supply Chain Information Integration Ability

    Institute of Scientific and Technical Information of China (English)

    王丘; 汤兵勇

    2012-01-01

    针对推拉驱动模式供应链驱动力的变化,在总结相关文献的基础上,构建了推拉驱动模式供应链信息整合能力测度的模糊综合评价指标体系,从物理设施、信息流程与信息内容、信息组织结构、信息用户体验与满意、供应链整体效益5个方面,结合实际调研资料,对种业供应链(A)与家电行业供应链(B)的信息整合能力进行了模糊综合评价.测度结果表明,所得出的量化指标符合测度对象信息整合能力的实际水平,对供应链运营策略的调整及运营绩效的提高能够起到积极的推进作用.%In connection with the change of the driving force of the push-pull driven mode supply chain, the fuzzy comprehensive evaluation system of information integration ability on the basis of summing up the relevant literatures was built. And the supply chain information ability from five aspects including the physical facility, information flow and information content, organizational structure of information, user experience and user satisfaction, the overall efficiency of the supply chain were also estimated combined with the actual research data. Two supply chains were estimated including a seed industry supply chain(A) and an appliance industry supply chain(B). The estimation results showed that the quantitative indicators were in line with the actual level of the information integration ability of the objects. And the result can actively push forward the strategy adjustment of supply chain operation and the improvement of operational performance.

  11. From Schedule Push to Reality Pull: Reality Pull prefers Retail

    NARCIS (Netherlands)

    drs. Frans van den Reep

    2005-01-01

    The Internet is changing the way we organise work. It is shifting the requirement for what we call the ‘schedule push’ and the hierarchical organisation that it implies, and therefore it is removing the type of control that is conventionally used to match resources to tasks, and customer demand to

  12. From Schedule Push to Reality Pull: Reality Pull prefers Retail

    NARCIS (Netherlands)

    Reep, Frans van der

    2005-01-01

    The Internet is changing the way we organise work. It is shifting the requirement for what we call the ‘schedule push’ and the hierarchical organisation that it implies, and therefore it is removing the type of control that is conventionally used to match resources to tasks, and customer demand to s

  13. College Students' Tourism Motivation Based on The Push-and-pull Theory:A Case Study for Students from Guizhou Normal University%基于推拉理论分析的大学生旅游动机实证研究——以贵州师范大学学生为例

    Institute of Scientific and Technical Information of China (English)

    杨洋

    2011-01-01

    The study on tourism motivation is the important content of study on tourist.Based on the research into students' tourism motivation in Guizhou Normal University,it holds that there are five push factors and five pull factors according toThe Push-and-pull Theory.The differences resulted from push factors and pull factors for different demographic characteristics are also analyzed,for references for the development and subdivision of tourism market for students,especially for those from Guizhou Province.%旅游动机研究是旅游主体(旅游者)研究的重要内容.在贵州师范大学学生旅游动机问卷调查基础上,依据旅游动机推拉理论,运用SPSS17.0统计软件的因子分析方法,得出贵州师范大学学生旅游动机的5个推力因子和4个拉力因子.并以此为基础分析了在人口统计特征中推拉力因子所表现的差异.其结果对西部大学生尤其是贵州省大学生的旅游市场开发与细分提供一定的参考.

  14. Cyclic deformation behaviour of quenched and tempered 42CrMo4 (AISI 4140) at two-block push-pull-loading; Zum Wechselverformungsverhalten von verguetetem 42CrMo4 bei zweistufiger Zug-Druck-Beanspruchung

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, V. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Werkstoffkunde 1; Lang, K.-H.; Voehringer, O.; Macherauch, E.

    1998-11-01

    The behaviour of steels in the course of two- and multi-block cyclic loading has been investigated up to now almost exclusively regarding the fatigue life. According to this, only a few papers exist, dealing with the cyclic deformation behaviour at two- and multi-block-push-pull-loading. Therefore, in stress- and total strain-controlled experiments with a single change of the amplitude (two-block-experiments) and multiple changes between two blocks of different lengths and amplitudes (multi-block-experiments) the cyclic deformation processes have been investigated for the quenched and tempered steel grade 42 CrMo 4 (equivalent to AISI 4140). Using the data of stress- and strain-Woehler-curves determined in usual fatigue tests, damages defined according to Miner`s rule were adjoined to the blocks. The Miner-damages at failure observed in the two-block-experiments with changes from high to low amplitudes were smaller than one and at inverse changes of amplitudes larger than one. In contrast to this, in multi-block-experiments no universally valid correlations were observed between the Miner-damages at failure and the test-parameters applied. At all tests cyclic work-softening was observed as in single-step-experiments. However, work-softening processes at high amplitude loadings yield to much larger plastic strain amplitudes after changing to smaller amplitudes than in single-step tests. Contrarily, in multi-block-tests work-softening at higher amplitude loadings reduces with decreasing block-length and increasing portion of the blocks with the smaller amplitude. This is attributed to effects of static strain-ageing. Total-strain-controlled two-block cyclic deformation experiments yield to similar effects as in stress-controlled tests. 18 refs.

  15. 推拉行为工效学测量与评估方法的研究进展%Research Progresses on Ergonomics Assessment and Measurement Methods for Push-pull Behavior

    Institute of Scientific and Technical Information of China (English)

    赵岩; 李东旭

    2011-01-01

    Pushing and pulling (P&P) is a common operating mode of operator's physical works, and plays an important role in evaluation of human behavior health and operation performance. At present, there are many research methods of P&P, and this article is a state-of-art review of the classification of P&P research methods, the various impact factors in P&P program, technical details of internal/external P&P force measurement and evaluation, the limitation of current research methods and the future developments in the ergonomics field.%推拉行为(P&P)是操作者体力工作任务中常见的一种作业方式,在人体行为健康与操作绩效研究与评估中占有重要的地位.研究与评估推拉行为的工效学方法种类很多,本文根据国内外相关领域的研究进展情况,全面地综述了推拉行为研究方法的分类,推拉行为过程中的影响因素及内/外力的测量与评估方法现状,并对当前P&P测量与评估方法中存在的问题及在未来工效学领域中的发展趋向进行了分析.

  16. Push-pull effect on the geometrical, optical and charge transfer properties of disubstituted derivatives of mer-tris(4-hydroxy-1,5-naphthyridinato aluminum (mer-AlND3

    Directory of Open Access Journals (Sweden)

    Rao Joshi Laxmikanth

    2016-01-01

    Full Text Available To design innovative and novel optical materials with high mobility, two kinds of disubstituted derivatives for mer-tris(4-hydroxy-1,5-naphthyridinato aluminum (mer-AlND3 with push (EDG–pull (EWG substituents have been designed. The structures of mer-tris(8-EDG-2-EWG-4-hydroxy-1,5-naphthyridinato aluminum (type I and mer-tris(8-EWG-2-EDG-4-hydroxy-1,5-naphthyridinato aluminum (type II in the ground and first excited states have been optimized at the B3LYP/6-31G(D and CIS/6-31G(D level of theory, respectively. It can be seen from frontier molecular orbitals analysis, in all these complexes, the highest occupied molecular orbital (HOMO is localized on the pyridine-4-ol ring of A-ligand while lowest unoccupied molecular orbital (LUMO is on the pyridyl ring of B-ligand in ground state irrespective of electron donor/acceptor substitution present on the ligands similar to that of mer-tris(8-hydroxyquinoline aluminum (mer-Alq3 and parent mer-AlND3.The absorption and emission wavelengths have been evaluated at the TD-PBE0/6-31G(D level and it can be see that all the type I derivatives show blue shift while most of the type II derivatives show red shift compared to mer-AlND3. All the disubstituted complexes have showed hypsochromic shifts in both the absorption and emission spectra when compared with the calculated absorption and emission spectra respectively of mer-Alq3. It can be seen that the reorganization energies of some of the disubstituted derivatives are comparable with mer-Alq3 and these derivatives might be good candidates for emitting materials in OLED.

  17. 推/拉型螺烯的前线分子轨道和电子光谱研究%Study on the Frontier Molecular Orbits and the Electronic Spectras of a Series of Push-Pull Helicenes

    Institute of Scientific and Technical Information of China (English)

    张新伟; 杨旭; 韩冰; 宋宣玉; 许军旗

    2014-01-01

    采用密度泛函理论B3LYP方法在6-31G( d, p)水平对一类推/拉型螺烯分子进行了几何结构优化,在得到稳定的分子构型后,用ZINDO/SCI方法计算了它们的前线分子轨道和电子光谱。结果表明,不同取代基和取代基的不同位置对分子的空间几何构型有一定的影响,HOMOs和LUMOs的分布特点说明该类分子有明显的电荷转移特征,通过优化设计不但可以提高非线性光学系数还可以增强这类分子的透明性。%The geometries of a series of push-pull helicenes were optimized by using density functional theory B3LYP method at the 6-31G (d, p) basis set level. Based on the obtained stable molecular configuration, the frontier molecular orbits and electronic spectras of these molecules were calculated by using the ZINDO/SCI method. The re-sults showed that the spatial molecular structures were different when the substituents or their positions were different. Through optimizing design, the distributions of HOMOs and LUMOs showed that these molecules have obviously charge transfer properties. Not only the nonlinear coefficients of this series of helicenes can be increased,but also the transpar-ences of such molecules can be enhanced.

  18. The pulling power of chocolate: Effects of approach-avoidance training on approach bias and consumption.

    Science.gov (United States)

    Dickson, Hugh; Kavanagh, David J; MacLeod, Colin

    2016-04-01

    Previous research has shown that action tendencies to approach alcohol may be modified using computerized Approach-Avoidance Task (AAT), and that this impacted on subsequent consumption. A recent paper in this journal (Becker, Jostman, Wiers, & Holland, 2015) failed to show significant training effects for food in three studies: Nor did it find effects on subsequent consumption. However, avoidance training to high calorie foods was tested against a control rather than Approach training. The present study used a more comparable paradigm to the alcohol studies. It randomly assigned 90 participants to 'approach' or 'avoid' chocolate images on the AAT, and then asked them to taste and rate chocolates. A significant interaction of condition and time showed that training to avoid chocolate resulted in faster avoidance responses to chocolate images, compared with training to approach it. Consistent with Becker et al.'s Study 3, no effect was found on amounts of chocolate consumed, although a newly published study in this journal (Schumacher, Kemps, & Tiggemann, 2016) did do so. The collective evidence does not as yet provide solid basis for the application of AAT training to reduction of problematic food consumption, although clinical trials have yet to be conducted.

  19. Push Vs Pull: Factors Influence Student Retention

    OpenAIRE

    Matthew Leone; Robert G. Tian

    2009-01-01

    Problem statement: Student retention becomes one of the most significant issues that administrators of colleges and universities must deal with in todays highly competitive market. Approach: In fact retaining a student is fundamental to the ability of an institution to carry out its mission. A high rate of attrition is not only a fiscal problem for schools, but a symbolic failure of an institution to achieve its purpose. Results: There are many ways to keep students retain at the same college...

  20. From schedule push to reality pull

    NARCIS (Netherlands)

    drs. Frans van den Reep

    2009-01-01

    The Internet is changing the way we organise work. It is shifting the requirement for what we call the ‘schedule push’ and the hierarchical organisation that it implies, and therefore it is removing the type of control that is conventionally used to match resources to tasks, and customer demand to

  1. From schedule push to reality pull

    NARCIS (Netherlands)

    Reep, Frans van der

    2009-01-01

    The Internet is changing the way we organise work. It is shifting the requirement for what we call the ‘schedule push’ and the hierarchical organisation that it implies, and therefore it is removing the type of control that is conventionally used to match resources to tasks, and customer demand to s

  2. Biosensor technology: technology push versus market pull.

    Science.gov (United States)

    Luong, John H T; Male, Keith B; Glennon, Jeremy D

    2008-01-01

    Biosensor technology is based on a specific biological recognition element in combination with a transducer for signal processing. Since its inception, biosensors have been expected to play a significant analytical role in medicine, agriculture, food safety, homeland security, environmental and industrial monitoring. However, the commercialization of biosensor technology has significantly lagged behind the research output as reflected by a plethora of publications and patenting activities. The rationale behind the slow and limited technology transfer could be attributed to cost considerations and some key technical barriers. Analytical chemistry has changed considerably, driven by automation, miniaturization, and system integration with high throughput for multiple tasks. Such requirements pose a great challenge in biosensor technology which is often designed to detect one single or a few target analytes. Successful biosensors must be versatile to support interchangeable biorecognition elements, and in addition miniaturization must be feasible to allow automation for parallel sensing with ease of operation at a competitive cost. A significant upfront investment in research and development is a prerequisite in the commercialization of biosensors. The progress in such endeavors is incremental with limited success, thus, the market entry for a new venture is very difficult unless a niche product can be developed with a considerable market volume.

  3. 低整流电压应力的推挽正激三电平变换器%Push-Pull Forward Three-Level Converter with Reduced Rectifier Voltage Stress

    Institute of Scientific and Technical Information of China (English)

    姚志垒; 肖岚; 黄勇; 丁连锋

    2012-01-01

    This paper presents a push-pull forward (PPF) three-level (TL) converter, which is suitable for low and wide-range input voltage applications, such as renewable energy resources. Half of the switches sustain half of the input voltage, and the others sustain one and one-half input voltage. However, voltage stress of the rectifier diode is high with the conventional TL control strategy, especially in high output-voltage condition, considering voltage spike across the rectifier diode caused by leakage inductance. When 1/2 level of the secondary rectified voltage shows first and 1 level of that appears later, the voltage stress across the rectifier diode can be reduced by paralleling with external capacitor. The operating principle and selection of the external capacitor are analyzed. Finally, experimental results of a 500 W PPF TL converter verify the theoretical analysis.%提出了一种推挽正激三电平变换器。它适合于低压宽输入的场合,如可再生能源。该变换器的一半开关管承受1/2的输入电压,另一半承受3/2的输入电压。采用传统的三电平控制策略,并考虑变压器漏感在整流二极管上产生的电压尖峰,整流二极管的电压应力高,尤其是在高输出电压的场合。为了解决上述问题,采用二次整流电压波形先出现1/2电平,后出现1电平的控制策略,并通过在整流二极管上并联电容的方法,降低了整流二极管的电压应力。该文详细分析了该变换器的工作原理,讨论了整流二极管并联电容的选取。最后,以一台500W的原理样机对理论分析并进行了实验验证。

  4. Capturing a synergistic effect of a conical push and an inward pull in fluoro derivatives of Li@B10H14 basket: toward a higher vertical ionization potential and nonlinear optical response.

    Science.gov (United States)

    Muhammad, Shabbir; Xu, Hongliang; Su, Zhongmin

    2011-02-10

    We present the design of fluoro derivatives of B(10)H(14) and Li@B(10)H(14) baskets. A synergistic effect of conical push and inward pull (reported independently in previous lithium nonlinear optical (NLO) complexes) has been explored in these derivatives to achieve a robustly large NLO response and a higher vertical ionization potential. Li@1,3,6,9-F(4)B(10)H(10), Li@6,9-F(2)B(10)H(12), and Li@2,4,6,9-F(4)B(10)H(10) exhibit first hyperpolarizability (β(0)) values as large as 181 624, 133 199, and 32 314 au; their vertical ionization potentials are 6.45, 6.30, and 6.78 eV, respectively. These values are significantly higher than those previously reported in Li-doped fluorocarbon chains at the same MP2/6-31+G* level of theory (Xu, H. L.; Li, Z. R.; Wu, D.; Wang, B. Q.; Li, Y.; Gu, F. L.; Aoki, Y. J. Am. Chem. Soc. 2007, 129, 2967). They also exceed those from our earlier designed Li@B(10)H(14) basket (Muhammad, S.; Xu, H. L.; Liao, Y.; Kan, Y. H.; Su , Z. M. J. Am. Chem. Soc. 2009, 131, 2967). In addition, new quantum chemical calculations of enthalpies of reaction (Δ(r)H°) at 298 K for B(10)H(14) and its lithium/fluoro derivatives highlight the changes in their thermodynamical aspects. The calculated enthalpies of lithiation reactions are -10.04, -11.29, and -13.18 kcal/mol for B(10)H(14), 6,9-F(2)B(10)H(12), and 2,4-F(2)B(10)H(12), respectively, demonstrating a higher probability of fluoro decaboranes for reaction with lithium. The obtained results not only explain the effect of position and number dependence of substituted fluoro atom(s) in B(10)H(14) and Li@B(10)H(14) but also elucidate a synergistic behavior to polarize a lithium excess electron for high NLO responses and vertical ionization potentials.

  5. Production and application of push-pull cable core for automobile control cable assembly%汽车控制索总成用推拉索索芯的生产及应用

    Institute of Scientific and Technical Information of China (English)

    张晓

    2013-01-01

    推拉索索芯是汽车控制索总成中的关键,其性能直接影响控制索总成的疲劳寿命.以1 +12-3.2索芯为例介绍索芯的生产及应用.索芯外层采用Φ0.60 mm的70钢丝,抗拉强度1770~1960 MPa,锌层面质量不小于60 g/m2;中心采用Φ2.0 mm的65 Mn钢丝,抗拉强度1670~1870 MPa,扭转、弯曲分别不小于18次、9次,断面收缩率不小于45%,金相组织为回火马氏体.捻制工艺参数:预变形器中心距19 mm,交换牙齿数比39∶56,收线力矩电机电压250~ 300 V,并采用在线光整以及在线轧制与锻打相结合的工艺技术,可批量、连续稳定地生产面接触钢丝绳.提出索芯在应用中的注意事项.%Push-pull cable core is key of automobile control cable assembly, its property impacts the fatigue life of control cable assembly directly. To take 1+12?. 2 cable core as an example, the production and application of cable core is introduced. Cable core outer layer adopts diameter 0.60 mm 70 steel wire, tensile strength is 1 770 ~ 1 960 MPa, zinc coat mass in no less than 60 g/m , cable core wire adopts diameter 2.0 mm 65 Mn steel wire, tensile strength is 1 670 ~ 1 870 MPa, torsion and bending are no less than 18,9 times respectively, area reduction is no less than 45% , microstructure is tempered martensite. Stranding process control parameters are as follows: predeformation apparatus center distance is 19 mm, exchange gear ratio is 39: 56, take-up torque motor voltage is 250 ~ 300 V. The process technology of online finishing, online rolling and forging combination is adopted, surface contact wire rope can be produced in quantity and continuous stable. The matters needing attention of application are proposed.

  6. The Applications and Implications of Push-pull Theory in Our Country' Rural-urban Migration%推-拉理论在我国乡-城劳动力转移中的应用与启示

    Institute of Scientific and Technical Information of China (English)

    刘晋强; 景普秋

    2015-01-01

    “三农”问题的关键环节是合理、有序地推进农村剩余劳动力向城镇、向非农产业转移,回顾乡—城劳动力转移经典模型发现,刘易斯模型和托达罗模型在应用于我国乡—城劳动力转移时存在一些缺陷。基于“推—拉”理论,首先分析了中国乡—城劳动力转移,并对模型进行了拓展。接着,围绕推力、拉力、摩擦力、助动力构建了指标体系,对影响我国乡—城劳动力转移的主要因素进行了实证分析。最后,提出了相关政策建议,来推动我国乡—城劳动力的进一步转移。%The key solution of the problems about agriculture, rural and peasantry is to advance the surplus rural labor to urban areas and non-agricultural industries reasonably and orderly. Through the review of the classical foreign theory of rural - urban migration, the study found that there are some defects when Lewis model and Todaro model are applied to China conditions. We analyze Chinese rural-urban migration based on"push-pull"theory, and extend the model, building the index system according to thrust, tension, friction, momentum, etc.,and carrying out the influencing factors of China's rural - urban migration through empirical analysis.Finally, the paper puts forward some policy recommendations to promote China's rural-urban migration orderly based on the results of the analysis.

  7. Ring-push metric learning for person reidentification

    Science.gov (United States)

    He, Botao; Yu, Shaohua

    2017-05-01

    Person reidentification (re-id) has been widely studied because of its extensive use in video surveillance and forensics applications. It aims to search a specific person among a nonoverlapping camera network, which is highly challenging due to large variations in the cluttered background, human pose, and camera viewpoint. We present a metric learning algorithm for learning a Mahalanobis distance for re-id. Generally speaking, there exist two forces in the conventional metric learning process, one pulling force that pulls points of the same class closer and the other pushing force that pushes points of different classes as far apart as possible. We argue that, when only a limited number of training data are given, forcing interclass distances to be as large as possible may drive the metric to overfit the uninformative part of the images, such as noises and backgrounds. To alleviate overfitting, we propose the ring-push metric learning algorithm. Different from other metric learning methods that only punish too small interclass distances, in the proposed method, both too small and too large inter-class distances are punished. By introducing the generalized logistic function as the loss, we formulate the ring-push metric learning as a convex optimization problem and utilize the projected gradient descent method to solve it. The experimental results on four public datasets demonstrate the effectiveness of the proposed algorithm.

  8. Pulled elbow.

    OpenAIRE

    1999-01-01

    Pulled elbow (distal subluxation of the radial head) is a common, painful condition in young children. Although it has been well documented it is often missed, often mistreated, and generally over-investigated. Treatment is simple and effective. Without treatment the condition can continue for several days.

  9. "Pushing the Limits": Rethinking Motor and Cognitive Resources After a Highly Challenging Balance Training Program for Parkinson Disease.

    Science.gov (United States)

    Leavy, Breiffni; Roaldsen, Kirsti Skavberg; Nylund, Kamilla; Hagströmer, Maria; Franzén, Erika

    2016-08-11

    There is growing evidence for the positive effects of exercise training programs on balance control in Parkinson disease (PD). To be effective, balance training needs to be specific, progressive, and highly challenging. Little evidence exists, however, for how people with PD-related balance impairments perceive highly challenging and progressive balance training programs with dual-task components. The purpose of this study was to explore and describe perceptions of a highly challenging balance training program among people with mild to moderate PD. This study was qualitative in nature. In-depth interviews were conducted with 13 individuals with mild to moderate PD who had participated in a highly challenging balance training program. Interview transcripts were analyzed using qualitative content analysis, with an inductive approach. The analysis revealed 3 subthemes concerning participants' perceptions of highly challenging and progressive balance training: (1) movement to counter the disease, (2) dual-task training in contrast to everyday strategies, and (3) the struggle to maintain positive effects. The first subtheme reflects how physical activity was used as a short-term and long-term strategy for counteracting PD symptoms and their progression. The second subtheme incorporates the described experiences of being maximally challenged in a secure and supportive group environment, circumstances that stood in contrast to participants' everyday lives. The third subtheme describes participants' long-term struggle to maintain program effects on cognitive and physical function in the face of disease progression. Interpretation of the underlying patterns of these subthemes resulted in one overarching theme: training at the limits of balance capacity causes a rethinking motor and cognitive resources. The findings of this study cannot be considered to reflect the beliefs of those with weaker or negative beliefs concerning physical activity or be transferred to those at

  10. 基于“推拉理论”的农业剩余劳动力转移研究--以山东省为例%Transfer of Agricultural Surplus Labor Based on the Push-pull Theory

    Institute of Scientific and Technical Information of China (English)

    刘云; 武舜臣

    2016-01-01

    在农村“推力”和城市“拉力”作用下,科学引导农业剩余劳动力的转移对加快我国工业化和城镇化进程具有重要意义。以山东省为例,选取1990—2013间相关的时间序列数据建立多元线性回归模型,运用主成分分析法和协整方程,实证分析农业剩余劳动力转移中各相关因素的作用规律。结果表明:城市就业空间的大小对农业剩余劳动力转移的作用最强,而从事非农劳动预期收入对劳动力转移的作用最弱;城镇失业率越低,阻碍劳动力转移的制度因素越弱,劳动力的文化素养和物质能力越强,对农业剩余劳动力的转移越有利。根据结果提出政策建议:不断提高农业劳动生产率,从而在农业中推出新的剩余劳动力,以便实现劳动力的后续转移;加快城市非农产业的发展,吸纳更多的农业剩余劳动力;加快以户籍制度为中心的改革。%As the countryside pushes and the city pulls labor force, the transfer of surplus agricultural labor force significantly is of great significance to China’s industrialization and urbanization. Taking Shandong Province as an example,this paper uses relevant data (1990—2013 )to establish the multi variable regression model and investigates the effect of the transfer of agricultural surplus labor. The results show that the size of urban employment has the strongest effect on the transfer of labor and that the income from engaging in non-agricultural labor has the weakest effect.At the same time,the lower the urban unemployment rate,the weaker the institutional factors to block the transfer.And the better the labor force’s cultural qualities and labor skills,the easier the transfer of surplus agricultural labor force.

  11. A Soft-switching Three-transistor Push-pull DC/DC Converter With LC Net in Parallel%并联LC网络的软开关三管推挽式直流变换器

    Institute of Scientific and Technical Information of China (English)

    袁义生; 伍群芳

    2013-01-01

    One three-transistor push-pull converter (TTPP converter) was proposed. The additional transistor Q3 is inserted between the input power source and midpoint of primary windings of the transformer. One LC element parallels with the transistor Q3. Two primitive transistors can realize zero-voltage turn-on because of the big energy of output inductor Lf. The LC net increases the energy of the leakage inductance before Q3 turn-on. As a result, Q3 can also achieve zero-voltage turn-on over a wide load range. The operation theory was discussed. The ZVS conditions of the three transistors were explained. The design of the LC net is investigated. A 800 W, 132 kHz prototype was built. Tests showed all power transistors can achieve ZVS at 86 W load. The peak efficiency of the prototype reaches 94.14%. Comparing the proposed TTPP converter with the basic TTPP converter, the efficiency of proposed converter is 2.31%higher than that of the basic converter.%提出一种采用3个开关管的软开关推挽电路。增加的开关管 Q3串接在输入电源和变压器原边绕组中间抽头之间。一个LC网络并联在Q3两端。因为输出滤波电感能量大,2个原始的开关管能够在宽负载范围内实现零电压开通。并联的LC网络增加了Q3开通前变压器漏感中的能量,使得Q3也能在宽负载范围下实现零电压开通。分析电路各工作阶段原理,讨论软开关实现条件,阐述LC器件的设计。完成一台800 W、开关频率为132 kHz的原理样机,样机在86 W下就能实现所有开关管的零电压开通,样机最高效率达到94.14%。测试比较了所提电路和基本的三管推挽电路的效率,结果表明,所提电路在轻载下比基本电路效率高2.31%。

  12. Positivism Study of Push and Pull Factors Made by Archaic Capital Inbound Tourist——Taking Nanjing for Example%古都城市入境旅游推-拉力因素实证研究——以南京市为例

    Institute of Scientific and Technical Information of China (English)

    郑长海; 马耀峰; 王冠孝; 张佑印

    2009-01-01

    This research took Nanjing as an example,based on an investigation into the tourism market,passed push and pull factors single essential factor evaluation model,the quantitative analysis ancient capital inbound tourist's traveling motive,and through the differences analysis of push and pull factors to the different community tourists,pointed out the traveling motive's different factor in the different community's influence,might provide certain basis for the market development of ancient capital's inbound tourist.%以南京市为例,在旅游市场调查的基础上,通过推-拉力因素单要素评价模型,定量研究了古都类城市入境游客的旅游动机,并通过对不同群体游客推-拉力因素的差异分析,进一步指出了旅游动机的不同因素在不同群体中的影响程度,可为古都类城市入境旅游市场拓展提供科学依据.

  13. 基于推-拉理论的地方高校高层次人才引进与管理--以武夷学院引进台湾博士为例%On Introduction and Management of High-level Talents in Local Universities Based on Push-Pull Theory---Taking the Introduction of Taiwan Doctors in Wuyi Universities as an Example

    Institute of Scientific and Technical Information of China (English)

    施晓莉

    2015-01-01

    加强高层次人才的引进与管理,是当前地方高校师资队伍建设的重中之重。文章以推-拉理论为理论视角,以武夷学院引进台湾博士为案例,分析近几年台湾博士流动现象,提出地方高校高层次人才养心、养学、养能和养情的管理策略。%The introduction and management of high-level talents are important for the construction of teachers team in local university currently.Based on the push-pull theory and taking the introduction of Taiwan doctors in Wuyi University as a case,the article attempts to interpret the flowing issues of Taiwan doctors and puts forward management strategies of high-level talents in local universities from the four dimensions of training the heart,the learning,the ability and the emotion etc.

  14. 中国农村人口流动的影响因素与实施对策--基于推拉理论的托达罗修正模型%Driving Factors and the Suggestion of Rural Population Mobility in China:Based on the "Push and Pull Theory "in Amended Todar Migration Model

    Institute of Scientific and Technical Information of China (English)

    张坤

    2014-01-01

    T here is a huge number of rural surplus labor exist in China ,how to realize the effective transfer of rural surplus labor on the situation of high unemployment rate in urban area is an important measure to push forward the urbanization ,promote the farmer's income ,maintain the social stability and the economic sustainable development .Based on Todar migration model ,the paper introduced the "push and pull theory" and combined with the current situation of Chinese rural population mobility to amend primary Todar migration model .Then ,the paper established a regression model and used the stepwise regression to give an analysis .The result of the regression analysis shows that :in the process of rural population mobility , we should firstly , accelerate the development of secondary industry and tertiary industry ,and enforce the training of the professional migrant workers ;secondly ,deepen the reformation and break the barrier of urban -rural segmentation so as to build a social welfare system which in favor of convergence;thirdly ,accelerate the industrialization and urbanization ;fourthly ,establish an unified labor market for cities and rural area ,so as to further promote the surplus labors shift from rural area to urban area effectively .%中国农村剩余劳动力数量巨大,如何在城市就业空间有限的情况下有效地解决中国农村剩余劳动力的合理转移问题,是推进城镇化和提升农民收入以及实现社会稳定和可持续发展的重要举措之一。在托达罗人口流动模型的基础上,引入“推拉理论”,结合中国农村人口流动实际状况,对托达罗人口流动模型进行修正,并以此构建多元回归模式进行逐步回归分析,结果表明:在农村人口流动的过程中应当加快第二、第三产业的发展,加大培训“农民工”专业技能的力度;深化体制改革,消除城乡二元分割的制度壁垒,构建城乡衔接的社会福利制度;加

  15. A Comparison Simulation on RFID-Enabled Hybrid Push/Pull and (s,S) Strategy for Multi-Echelon Inventory%多级库存 RFID使能的 Push/Pull与(s,S)策略的仿真对比

    Institute of Scientific and Technical Information of China (English)

    李国家; 汪定伟

    2014-01-01

    基于RFID使能的电子看板以供应链分销网络三级库存系统为例,根据其结构特点和运作时各阶段节点企业的功能,借鉴单工厂多阶段生产存储系统最优的Push/Pull混合控制结构,设计了制造商库存采用Push控制,分销商和零售商库存采用RFID使能的Pull控制的RFID使能的Push/Pull混合控制结构。为验证混合控制策略的性能,将其与基于RFID技术的( s,S)策略相对比,建立了两策略的数学模型及性能评价指标。考虑到供应链系统的动态性与随机性,基于离散事件系统仿真原理,设计并实现了系统的仿真模型,通过仿真实例验证并分析了混合控制策略的有效性和优越性,为供应链多级库存网络管理实践提供了参考。%The three-echelon inventory network of supply chain distribution system is exemplified to design the RFID-enabled Push/Pull hybrid control strategy by which the manufacture is controlled by Push and the distribution and retailers are controlled by RFID-enabled Pull .This design is based on RFID-enabled electronic Kanban system and according to the structural characteristics of the supply chain and the func -tions of the enterprises in different stages when the supply chain runs .It should be noted that this design draws lessons from the optimal Push/Pull hybrid control structure applied in the single factory multi-stage production storage system .To verify the performance of the hybrid strategy , the strategy is compared with the ( s,S) strategy based on the RFID .Considering the dynamic and stochastic nature of the supply chain system , the simulation models of system based on the principle of discrete event system simulation are de -signed and realized .Finally , the RFID-enabled hybrid Push/Pull control strategy is demonstrated to be valid and superior by simulation examples .It is assumed that this research provides reference for the man-agement practice of the multi

  16. The Influence of the Change of Gambling Industry Income on the Migration of Labor Force in Macao---Based on the Empirical Study of the Push Pull Theory%博彩收入变动对澳门迁入劳动力的影响--基于推拉理论的本土化拓展分析与实证研究

    Institute of Scientific and Technical Information of China (English)

    袁健

    2016-01-01

    Based on labor economics push-pull model , empirical analysis on the influence of the change of gambling industry income on the migration of labor force in Macao show that the Macao economic devel-opment of the pull agent variable for each increase of 1% ,it will pull into the labor force of 2.44% ;Macao economic development of the push agent variable for each increase of 1% will be reduced to migration of la-bor force 35.67% .This study further updates and enriches the scope of labor economics push-pull model theoretically ,and provides timely reference for the Macao economic development strategy in practice .%基于劳动经济学推拉模型对实证分析博彩收入变动对澳门迁入劳动力影响的结果表明,澳门经济发展的拉力代理变量每提升1%,就会拉动迁入劳动力的2.44%;澳门经济发展的推力代理变量每提升1%,将会减少迁入外地劳动力35.67%。本研究在理论上进一步更新和充实了劳动经济学推拉模型的适用范围,实践上为澳门经济发展战略走向提供了时效性参考。

  17. Ultrafine particle air pollution inside diesel-propelled passenger trains.

    Science.gov (United States)

    Abramesko, Victoria; Tartakovsky, Leonid

    2017-04-05

    Locomotives with diesel engines are used worldwide and are an important source of air pollution. Pollutant emissions by locomotive engines affect the air quality inside passenger trains. This study is aimed at investigating ultrafine particle (UFP) air pollution inside passenger trains and providing a basis for assessing passenger exposure to this pollutant. The concentrations of UFPs inside the carriages of push-pull trains are dramatically higher when the train operates in pull mode. This clearly shows that locomotive engine emissions are a dominant factor in train passengers' exposure to UFPs. The highest levels of UFP air pollution are observed inside the carriages of pull trains close to the locomotive. In push mode, the UFP number concentrations were lower by factors of 2.6-43 (depending on the carriage type) compared to pull mode. The UFP concentrations are substantially lower in diesel multiple-unit trains than in trains operating in pull mode. A significant influence of the train movement regime on the UFP NC inside a carriage is observed.

  18. Design of a Polymer Directional Coupler Electro-Optic Switch with Low Push-Pull Switching Voltage at 1550nm%1550nm低推挽电压聚合物定向耦合电光开关的设计

    Institute of Scientific and Technical Information of China (English)

    郑传涛; 马春生; 闫欣; 王现银; 张大明

    2008-01-01

    A polymer directional coupler (DC) electro-optic switch with push-pull electrodes and rib waveguides is designed based on the conformal transforming method, image method, coupled mode theory, and electro-optic modulation theory. Its structure and principle are described, the design and optimization are performed, and the characteristics are analyzed,including the coupling length, switching voltage, output power, insertion loss, and crosstalk. To realize normal switching function, the fabrication tolerance, wavelength shift, and coupling loss between a single mode fiber (SMF) and the waveguide are discussed. Simulation results show that the coupling length is 3082μm; the push-pull switching voltage is 2.14V;and the insertion loss and crosstalk are less than 1.14 and -30dB, respectively. The proposed analytical technique on waveguides and electrodes is proven to be accurate and computationally efficient when compared with the beam propagation method (BPM) and the experimental results.%应用保角变换法、镜像法、耦合模理论和电光调制理论设计了一种推挽电极聚合物脊形波导定向耦合电光开关,阐述了基本结构和工作原理,给出了器件的设计和优化过程,主要分析了耦合长度、开关电压、输出光功率、插入损耗、串扰等特性.为了实现正常的开关功能,讨论了制作公差、波谱漂移以及单模光纤耦合损耗对器件性能的影响.模拟结果表明,所设计的开关的耦合长度为3082μm,开关电压为2.14V;插入损耗小于1.14dB,串扰小于-30dB.与BPM仿真结果以及实验结果的对比表明,文中提出的波导和电极的理论分析与计算方法具有较高的精度和可行性.

  19. Microdroplet oscillations during optical pulling

    CERN Document Server

    Ellingsen, Simen Å

    2011-01-01

    It was recently shown theoretically that it is possible to pull a spherical dielectric body towards the source of a laser beam [Nature Photonics {\\bf 5}, 531 (2011)], a result with immediate consequences to optical manipulation of small droplets. Optical pulling can be realised e.g.\\ using a diffraction free Bessel beam, and is expected to be of great importance in manipulation of microscopic droplets in micro- and nanofluidics. Compared to conventional optical pushing, however, the radio of optical net force to stress acting on a droplet is much smaller, increasing the importance of oscillations. We describe the time-dependent surface deformations of a water microdroplet under optical pulling to linear order in the deformation. Shape oscillations have a lifetime in the order of microseconds for droplet radii of a few micrometers. The force density acting on the initially spherical droplet is strongly peaked near the poles on the beam axis, causing the deformations to take the form of jet-like protrusions.

  20. Weightlifting pulling derivatives: rationale for implementation and application.

    Science.gov (United States)

    Suchomel, Timothy J; Comfort, Paul; Stone, Michael H

    2015-06-01

    This review article examines previous weightlifting literature and provides a rationale for the use of weightlifting pulling derivatives that eliminate the catch phase for athletes who are not competitive weightlifters. Practitioners should emphasize the completion of the triple extension movement during the second pull phase that is characteristic of weightlifting movements as this is likely to have the greatest transference to athletic performance that is dependent on hip, knee, and ankle extension. The clean pull, snatch pull, hang high pull, jump shrug, and mid-thigh pull are weightlifting pulling derivatives that can be used in the teaching progression of the full weightlifting movements and are thus less complex with regard to exercise technique. Previous literature suggests that the clean pull, snatch pull, hang high pull, jump shrug, and mid-thigh pull may provide a training stimulus that is as good as, if not better than, weightlifting movements that include the catch phase. Weightlifting pulling derivatives can be implemented throughout the training year, but an emphasis and de-emphasis should be used in order to meet the goals of particular training phases. When implementing weightlifting pulling derivatives, athletes must make a maximum effort, understand that pulling derivatives can be used for both technique work and building strength-power characteristics, and be coached with proper exercise technique. Future research should consider examining the effect of various loads on kinetic and kinematic characteristics of weightlifting pulling derivatives, training with full weightlifting movements as compared to training with weightlifting pulling derivatives, and how kinetic and kinematic variables vary between derivatives of the snatch.

  1. Hair Pulling (Trichotillomania)

    Science.gov (United States)

    ... Facts for Families Guide Facts for Families - Vietnamese Hair Pulling (Trichotillomania) No. 96; Reviewed July 2013 It ... for children and adolescents to play with their hair. However, frequent or obsessive hair pulling can lead ...

  2. Pushing Back against Push-In: ESOL Teacher Resistance and the Complexities of Coteaching

    Science.gov (United States)

    McClure, Greg; Cahnmann-Taylor, Melisa

    2010-01-01

    As U. S. school districts struggle to address persistent achievement gaps between increasing numbers of English language learners (ELLs) and their native-English-speaking counterparts, many districts are moving away from segregative models like pull-out to implement more collaborative approaches such as coteaching, or push-in. In contrast to…

  3. 盐酸氨溴索推挽式渗透泵控释片的制备及犬体内药动学%Preparation of Ambroxol Hydrochloride Push-pull Osmotic Pump Controlled-release Tablets and Its Pharmacokinetics in Dogs

    Institute of Scientific and Technical Information of China (English)

    赵锋; 马银玲; 金晓利; 王静; 曹德英

    2011-01-01

    以不同分子量的聚氧化乙烯为助悬剂和膨胀剂,制备盐酸氨溴索推挽式渗透泵控释片.采用相似因子(f_2)为评价指标,考察含药层中助悬剂种类和助推层中膨胀剂种类的影响.通过正交试验优化处方,考察自制片的体外释放行为和释药机理,并考察其在Beagle犬体内的药动学行为.结果表明,自制片零级释药特征明显(r=0.9921)、释药完全(90%).释药机理符合渗透泵原理且体外释放行为不受片芯直径、硬度、转速及释放介质pH的影响;体内外相关性良好(r=0.984 9).%The push-pull osmotic pump-based controlled-release tablets loaded with ambroxol hydrochloride were prepared, with polyethylene oxide of different molecular weight as suspending agent and extender.Using similar factor (f2) as evaluation index, different suspending agent in drug layer and different extender in push layer were investigated by in vitro release.Following orthogonal design, in vitro release and release mechanism of the preparation were investigated.The pharmacokinetics of the preparation in Beagle dogs was also studied.The results showed that the preparation possessed character of zero-order release (r=0.992 1) and drug release completely (90 %).The pH of media and rotation speed had no significant effect on the in vitro release, while hardness and size of tablets hardly influenced.The correlation coefficient between the fraction of absorption in vivo and the release rate in vitro was 0.984 9.

  4. 供应链中控制多级存储的射频辨识Push/Pull混合策略设计与仿真%Design and simulation of radio frequency identification-enabled hybrid Push / Pull strategy for multi-echelon inventory of supply chain

    Institute of Scientific and Technical Information of China (English)

    李国家; 汪定伟

    2014-01-01

    由于射频辨识(radio frequency identification,RFID)激励的电子看板系统能够从远端看见供应链节点企业库存的状况,使得广域分布的供应链多级存储能够实现RFID激励的Pull控制.本文根据供应链分销网络多级存储的结构特点,以及系统运作期间各阶段节点企业的功能,在不同阶段采用不同的控制策略.因此,设计了多种不同的RFID激励的Push/Pull混合控制策略.为了比较和验证各混合策略对多级存储的控制性能,建立了以总库存成本、总缺货损失、总运行成本和库存周转率作为评价策略性能的指标体系.由于供应链系统的动态性与随机性,难以进行数学建模和精确求解,因此基于离散事件系统仿真原理,设计并实现了仿真模型.通过对各策略下多种结构的供应链分销网络多级存储的仿真,验证并分析了制造商阶段采用Push控制,分销商和零售商阶段采用Pull控制的策略的有效性和最优性.

  5. Study on the technology roadmapping for open fuzzy front end: integration of market pull and technology push%开放式模糊前端的技术路线图研究——市场拉力与技术推力的结合

    Institute of Scientific and Technical Information of China (English)

    盛济川; 曹杰

    2012-01-01

    在T-plan和技术推力方法(MTP)的基础上,将开放式创新和技术路线图引入模糊前端,提出了开放式模糊前端的技术路线图(TROFFE),通过三个阶段的六次决策,绘制出创意的技术路线图并用于降低模糊前端的不确定性,并通过开放式创新获取市场和技术的信息。同时将技术推力和市场拉力有效结合起来,不区分创意的产生来源,使得该方法具有更广泛的适用性。%Based on T-plan and the method of technology push(MTP),the technology roadmapping for open fuzzy front end(TROFFE) is proposed though introducing open innovation and technology roadmapping(TRM) into fuzzy front end(FFE).The roadmap for the initial idea which is developed by six decisions of three stages can be used to reduce the uncertainty of FFE,and the information of market and technology can be obtained by open innovation.The method of TROFFE had a wide range of application,because of ignoring the source of idea by the integration of market pull and technology push.

  6. Study on in vitro release and bioequivalence in Beagle dogs of ambroxol hydrochloride push-pull osmotic pump controlled-release tablets%盐酸氨溴索双层渗透泵控释片体外释放及Beagle犬生物等效性

    Institute of Scientific and Technical Information of China (English)

    马银玲; 赵锋; 金晓利; 王静; 曹德英

    2011-01-01

    目的:研究自制片的体外释药行为及体内生物等效性.方法:采用相似因子(f2)为评价指标,考察自制片的体外释放行为;采用单剂量交叉试验考察Beagle犬口服自制片与参比制剂的生物等效性及体内外相关性.结果:自制片体外释放零级特征明显(r=0.992 1)且释药完全(90%).犬体内两制剂生物等效,相对生物利用度(100.0±12.6)%,自制片体内外相关性良好(r=0.98).结论:盐酸氨溴索双层渗透泵控释片具有很好的开发前景.%OBJECTIVE In vitro release and bioequivalence of self-made tablets were evaluated. METHODS Using similar factor (f2) as evaluate index, in vitro release of self-made tablets were evaluated. In vivo study, ultilizing Beagle dogs orally single-dose crossing administrated, the bioequivalence between the self-made controlled-release tablets and marketed sustained capsules and the correlation coefficient between the fraction of absorption in vivo and the release rate in vitro were investigated. RESULTS Self-made tablets possessed character of zero-order release (r = 0.992 1) and drug release completely(90%) in vitro release. The relative bioavailability was (100. 0 ± 12. 6) %. The correlation coefficient between the fraction of absorption in vivo and the release rate in vitro was 0. 98. CONCLUSION Ambroxol hydrochloride push-pull osmotic pump controlled-releasetablets have much developing potential.

  7. 内嵌乙硅烷的推拉型有机分子的二阶非线性光学性质的理论研究%Theoretical Study on the Second-order Nonlinear Optical Property of Push-pull Organic Molecules with an Embedded Disilane

    Institute of Scientific and Technical Information of China (English)

    黄德林; 高艳蓉; 余盛萍; 陈彬彬; 杨明理

    2015-01-01

    The structure, electronic and nonlinear optical property of a series of push-pull organic molecules with an embedded disilane is studied using density functional theory calculation.These molecules possess a typical electron donor-conjugation path-electron acceptor structure in which the conjugation path is partly blocked by the saturate Si-Si bond of disilane.The conjugation nature of these molecules then varies and leads to significant change in their electronic absorption spectra, dipole moment, polarizability, hyperpolarizability and crystallization.A strategy for optimizing the NLO response of these chromophores is proposed upon a comparative study of their electronic structures.%用密度泛函理论方法计算了系列含乙硅烷的推拉型有机分子的结构、电子性质和非线性光学( NLO)性质。该系列分子具有典型的电子供体-共轭桥-电子受体结构,其中乙硅烷的饱和Si Si键嵌入共轭桥,改变了共轭体系的电子性质,导致分子的电子吸收光谱、偶极矩、极化率、超极化率、结晶行为等发生显著改变。在比较研究该系列化合物电子结构的基础上,提出了进一步优化其NLO响应的方法。

  8. Exocyclic push-pull conjugated compounds. Part 3. An experimental NMR and theoretical MO ab initio study of the structure, the electronic properties and barriers to rotation about the exocyclic partial double bond in 2- exo-methylene- and 2-cyanoimino-quinazolines and -benzodiazepines

    Science.gov (United States)

    Benassi, R.; Bertarini, C.; Hilfert, L.; Kempter, G.; Kleinpeter, E.; Spindler, J.; Taddei, F.; Thomas, S.

    2000-03-01

    The structure of a number of 2- exo-methylene substituted quinazolines and benzodiazepines, respectively, 1, 3a, b, 4( X=-CN, -COOEt ) and their 2-cyanoimino substituted analogues 2, 3c, d( X=-CN, -SO 2C 6H 4-Me (p) was completely assigned by the whole arsenal of 1D and 2D NMR spectroscopic methods. The E/ Z isomerism at the exo-cyclic double bond was determined by both NMR spectroscopy and confirmed by ab initio quantum chemical calculations; the Z isomer is the preferred one, its amount proved dependent on steric hindrance. Due to the push-pull effect in this part of the molecules the restricted rotation about the partial C 2,C 11 and C 2,N 11 double bonds, could also be studied and the barrier to rotation measured by dynamic NMR spectroscopy. The free energies of activation of this dynamic process proved very similar along the compounds studied but being dependent on the polarity of the solvent. Quantum chemical calculations at the ab initio level were employed to prove the stereochemistry at the exo-cyclic partial double bonds of 1- 4, to calculate the barriers to rotation but also to discuss in detail both the ground and the transition state of the latter dynamic process in order to better understand electronic, inter- and intramolecular effects on the barrier to rotation which could be determined experimentally. In the cyanoimino substituted compounds 2, 3c, d, the MO ab initio calculations evidence the isomer interconversion to be better described by the internal rotation process than by the lateral shift mechanism.

  9. 代际差异视角下农民工乡城迁移与宅基地退出影响因素分析——基于推拉理论的实证研究%Analysis of Influential Factors of Withdrawing from Rural Residential Land and Migrant Workers' Urban-Rural Migration under the Perspective of Intergenerational Differences: An Empirical Study on the Basis of Push-Pull Theory

    Institute of Scientific and Technical Information of China (English)

    许恒周; 殷红春; 石淑芹

    2013-01-01

    在2011年天津市农民工调查数据的基础上,本文借鉴推拉理论重新梳理影响农民工城乡迁移与宅基地退出意愿的因素,建立了农民工宅基地退出影响因素的推拉分析框架,并通过实证研究析出和显化在不同代际农民工城乡迁移和宅基地退出过程中起关键作用的因素.研究发现:在推力因素方面,对第一代农民工宅基地退出意愿产生较大影响的因素主要是年龄、受教育程度、宅基地在住房养老中的作用、供养系数和对农村基础设施满意程度;对新生代农民工宅基地退出意愿产生较大影响的因素主要有性别、教育程度、供养系数和对农村基础设施满意程度.在拉力因素方面,对第一代农民工宅基地退出意愿产生较大影响的因素主要是有无专业培训经历或证书、是否签订劳动合同、区位、单位性质和外出务工时所利用的方式;对新生代农民工宅基地退出意愿产生较大影响的因素主要是有无专业培训经历或证书、是否签订劳动合同、区位、单位性质、外出务工时所利用的方式和是否同城里的人交过朋友.在此基础上,提出了相应的政策建议.%Based on the survey data which was conducted on 613 migrant workers in Tianjin in 2011,this paper used the push-pull theory to analyze the factors that affect the migrant workers' willingness of rural-urban migration and withdrawing from the rural residential land,established the theoretical framework for influential factors,and then empirically studied the key factors that affect the withdrawing from rural residential land between the different generations of migrant workers.The results show that in the aspect of pushing,the factors that have significant influences on the willingness of withdrawing from residential land for the old-generation of migrant workers mainly include age,education,the effect of residential land in aged insurance

  10. Segmentation of rural tourists: combining push and pull motivations

    OpenAIRE

    Juho A. Pesonen

    2012-01-01

    Rural tourism is an important form of tourism in many countries, including Finland. To understand rural tourists’ behaviour and help tourism companies market their products more efficiently many scholars have segmented rural tourists in several different geographical locations. This study aims to combine segmentation approaches used in earlier studies, namely motivation and benefit segmentation, and segment online rural tourists in Finland. Data is collected in a rural tourism affiliate we...

  11. From Push To Pull: Emerging Models For Mobilizing Resources

    Directory of Open Access Journals (Sweden)

    John Hagel III

    2011-05-01

    Full Text Available The signs are around us.  We are on the cusp of a shift to a new common sense model that will re-shape many facets of our life, including how we identify ourselves, participate with others, connect with others, mobilize resources and learn.  This paper will focus on only one facet of this new common sense model – emerging approaches for mobilizing resources.

  12. SEGMENTATION OF RURAL TOURISTS: COMBINING PUSH AND PULL MOTIVATIONS

    National Research Council Canada - National Science Library

    Juho A Pesonen

    2012-01-01

    .... To understand rural tourists' behaviour and help tourism companies market their products more efficiently many scholars have segmented rural tourists in several different geographical locations...

  13. MEMS and mil/aero: technology push and market pull

    Science.gov (United States)

    Clifford, Thomas H.

    2001-04-01

    MEMS offers attractive solutions to high-density fluidics, inertial, optical, switching and other demanding military/aerospace (mil/aero) challenges. However, full acceptance must confront the realities of production-scale producibility, verifiability, testability, survivability, as well as long-term reliability. Data on these `..ilities' are crucial, and are central in funding and deployment decisions. Similarly, mil/aero users must highlight specific missions, environmental exposures, and procurement issues, as well as the quirks of its designers. These issues are particularly challenging in MEMS, because of the laws of physics and business economics, as well as the risks of deploying leading-edge technology into no-fail applications. This paper highlights mil/aero requirements, and suggests reliability/qualification protocols, to guide development effort and to reassure mil/aero users that MEMS labs are mindful of the necessary realities.

  14. Adult Literacy in Africa: The Push and Pull Factors

    Science.gov (United States)

    Omolewa, Michael

    2008-01-01

    This paper examines the question of why Africa has made such slow progress towards the goal of eradicating illiteracy, and why it remains an exceptionally disadvantaged region in this respect. The article surveys the history of the development of literacy in Africa from colonial times to the present day, focusing on the role of adult education in…

  15. From Push to Pull: Barriers to MALSP Modernization

    Science.gov (United States)

    2013-03-01

    productively. Marine aviation logisticians envision a much leaner , more agile, and more responsive system scalable to fit limited contingency...and change: autonomy (30%), incentives (22%), and organizational support (36%; p. 6). Read and Dew’s research suggested that for a wide-scale change

  16. Adult Literacy in Africa: The Push and Pull Factors

    Science.gov (United States)

    Omolewa, Michael

    2008-01-01

    This paper examines the question of why Africa has made such slow progress towards the goal of eradicating illiteracy, and why it remains an exceptionally disadvantaged region in this respect. The article surveys the history of the development of literacy in Africa from colonial times to the present day, focusing on the role of adult education in…

  17. An Adaptive Push/Pull Algorithm for AJAX Applications

    NARCIS (Netherlands)

    Bozdag, E.; Van Deursen, A.

    2008-01-01

    Preprint of paper published in: AEWSE 2008 - Proceedings of the Third International Workshop on Adaptation and Evolution in Web Systems Engineering, 16 July 2008 Even though the AJAX paradigm helps web applications to become more responsive, AJAX alone does not provide an efficient mechanism for

  18. A Comparison of Push and Pull Techniques for AJAX

    NARCIS (Netherlands)

    Bozdag, E.; Mesbah, A.; Van Deursen, A.

    2007-01-01

    AJAX applications are designed to have high user interactivity and low user-perceived latency. Real-time dynamic web data such as news headlines, stock tickers, and auction updates need to be propagated to the users as soon as possible. However, AJAX still suffers from the limitations of the Web’s r

  19. An Adaptive Push/Pull Algorithm for AJAX Applications

    NARCIS (Netherlands)

    Bozdag, E.; Van Deursen, A.

    2008-01-01

    Preprint of paper published in: AEWSE 2008 - Proceedings of the Third International Workshop on Adaptation and Evolution in Web Systems Engineering, 16 July 2008 Even though the AJAX paradigm helps web applications to become more responsive, AJAX alone does not provide an efficient mechanism for re

  20. Simple heuristics for push and pull remanufacturing policies

    NARCIS (Netherlands)

    E.A. van der Laan (Erwin); R.H. Teunter (Ruud)

    2004-01-01

    textabstractInventory policies for joint remanufacturing and manufacturing have recently received much attention. Most efforts, though, were related to (optimal) policy structures and numerical optimization, rather than closed form expressions for calculating near optimal policy parameters. The

  1. Optical Pulling Force and Tractor Beams

    Science.gov (United States)

    Paul, Nayan Kumar

    Light-matter interaction has been an interesting subject of intense analytical and experimental research since the formulation of Maxwell's electromagnetic wave theory. Optical forces exerted on particles excited by incident light waves have been studied for the last few decades. The interaction of light with materials gives rise to light scattering from the particle in the form of energy. The divergence of the Maxwell stress tensor provides a good approximation of the total optical forces on a particle. The divergence of the stress tensor is mathematically equal to the time average Lorentz force since [special characters omitted]. Others have claimed that the stress tensor is "fraught with danger," but it is a matter of application. The stress tensor approach is computationally simpler since application of the divergence theorem allows for a reduction of dimension in the integration. For example, you can either integrate the force density over the volume of an object (3-D), or integrate the divergence of the stress tensor on a surface (2-D) enclosing the volume. It gives a straightforward prediction of the total optical forces on a particle, but may be challenging in the case of multiple particles or for larger particles. The Rayleigh approximation estimates the radiation pressure on small particles in the propagation direction of light, but may be inappropriate for larger particles in comparison to the wavelength of the incident light waves. Light waves exert radiation pressure on a particle and pushes it away from the light source toward the direction of propagation. It is shown that plane waves propagating in a rectangular waveguide not only push a passive particle toward the propagation direction, but also pull it toward the light source. The particle remains trapped in the transverse direction of the rectangular waveguide. The Lorentz force and the Rayleigh approximation are applied to calculate the total force on the particle. The push-pull phenomenon

  2. On Reducing Delay in Mesh-Based P2P Streaming: A Mesh-Push Approach

    Science.gov (United States)

    Liu, Zheng; Xue, Kaiping; Hong, Peilin

    The peer-assisted streaming paradigm has been widely employed to distribute live video data on the internet recently. In general, the mesh-based pull approach is more robust and efficient than the tree-based push approach. However, pull protocol brings about longer streaming delay, which is caused by the handshaking process of advertising buffer map message, sending request message and scheduling of the data block. In this paper, we propose a new approach, mesh-push, to address this issue. Different from the traditional pull approach, mesh-push implements block scheduling algorithm at sender side, where the block transmission is initiated by the sender rather than by the receiver. We first formulate the optimal upload bandwidth utilization problem, then present the mesh-push approach, in which a token protocol is designed to avoid block redundancy; a min-cost flow model is employed to derive the optimal scheduling for the push peer; and a push peer selection algorithm is introduced to reduce control overhead. Finally, we evaluate mesh-push through simulation, the results of which show mesh-push outperforms the pull scheduling in streaming delay, and achieves comparable delivery ratio at the same time.

  3. Development of glipizide push-pull osmotic pump controlled release tablets by using expert system and artificial neural network%利用专家系统和人工神经网络开发格列吡嗪推拉式渗透泵控释片

    Institute of Scientific and Technical Information of China (English)

    张志宏; 王悦; 吴文芳; 赵曦; 孙晓翠; 王焕青

    2012-01-01

    本文目的在于利用专家系统和人工神经网络开发格列吡嗪推拉式渗透泵控释片.首先以瑞易宁实测释放度结果为目标,利用难溶性药物渗透泵处方设计专家系统设计处方;再根据系统给出的处方制备样品并利用体外释放度进行实验验证,并与瑞易宁进行动物体内药代动力学对比;最后利用人工神经网络对能影响产品释放的处方工艺范围进行优化和设计空间确定.结果发现,利用专家系统可以在极短时间内获得所需要的产品处方,其体外释放与市售制剂相似,与瑞易宁在Beagle犬体内生物等效,关键参数设计空间为包衣增重9.5%~12.0%.开发产品制定的释放度质量标准高于进口注册标准,利用人工智能的手段开发出质量优良的格列吡嗪控释片.%The purpose of this study is to develop glipizide push-pull osmotic pump (PPOP) tablets by using a formulation design expert system and an artificial neural network (ANN). Firstly, the expert system for the formulation design of osmotic pump of poor water-soluble drug was employed to design the formulation of glipizide PPOP, taking the dissolution test results of Glucotrol XL as the goal. Then glipizide PPOP was prepared according to the designed formulations and the in vitro dissolution was carried out. And in vivo evaluation was carried out between the samples which were similar to Glucotrol XL and the Glucotrol XL in Beagle dogs. The range of the factors of formulation and procedure, which could influence the drug release, was optimized using artificial neural network. Finally, the design space was found. It was found that the target formulation which was similar to Glucotrol XL in dissolution test could be obtained in a short period by using the expert system. The samples which were similar to Glucotrol XL were bio-equivalent to the Glucotrol XL in Beagle dogs. The design space of the key parameter coating weight gain was 9.5%—12.0%. It

  4. Local and Long-Range Hybrid Density Functional Study on an Organic Light-Emitting Molecule with Pull-Push Structure%局域和长程杂化密度泛函研究推拉结构有机发光分子

    Institute of Scientific and Technical Information of China (English)

    刘小君; 王宁; 程浩

    2011-01-01

    用含时密度泛函方法研究了具有推拉结构的有机发光材料3-(二氰亚甲基)-5,5-二甲基-1-(4-[9-咔唑基]-苯乙烯基)环己烯(DCDCC)的吸收和荧光光谱,并考虑了溶剂效应.通过与实验光谱的比较,重点评价了包括局域和长程在内的8种交换泛函.结果表明泛函的选择对结果的可靠性至关重要,在密度泛函和含时密度泛函理论框架下,包含44%Hartree Fock交换泛函的BMK杂化函数联同连续极化模型和中等大小的基组最适合研究DCDCC分子的光谱性质.此外,尽管DCDCC分子内电荷转移并没有强致发出双荧光,但仍然可以用平面分子内电荷转移和扭转分子内电荷转移模型解释DCDCC激发态的结构.BMK泛函计算的结果表明DCDCC的激发态结构支持平面分子内电荷转移模型.%The absorption and fluorescence spectra of 3-(dicyanomethylene)-5,5-dimethyl-1-(4-[9-carbazol]-styryl)cyclohexene (DCDCC), an organic light emitting material with pull-push structure, were investigated using a time-dependent density functional theory (TD-DFT) approach and bulk solvent effects were taken into account. The performance of eight exchange-correlation functionals including both local and long-range hybrids was assessed by comparing the calculated electron transition energies to experimental observations. It turns out that the appropriate choice of functionals is crucial to obtain an accurate value and BMK hybrids, which contain 44% Hartree Fock exchange, in the frame of DFT and TD-DFT with the polarizable continuum model and a medium sized basis set, emerges as an effective strategy for DCDCC. Moreover, the planar and twisted intramolecular charge transfer (PICT and TICT)models were used to interpret the excited state structure of DCDCC although the charge transfer character of the excited-state was not as intense as to emit obvious double fluorescence. The accurate structures were optimized by BMK and supported the PICT model.

  5. Pulling on adhered vesicles

    Science.gov (United States)

    Smith, Ana-Suncana; Goennenwein, Stefanie; Lorz, Barbara; Seifert, Udo; Sackmann, Erich

    2004-03-01

    A theoretical model describing pulling of vesicles adhered in a contact potential has been developed. Two different regimes have been recognized. For weak to middle-strength adhesive potentials, locally stable shapes are found in a range of applied forces, separated from the free shape by an energy barrier. The phase diagram contains regions with either a unique bound shape or an additional meta-stable shape. Upon pulling, these shapes unbind discontinuously since the vesicle disengage from the surface while still possessing a finite adhesion area (Smith 2003a). In a strong adhesion regime, a competition between adhesion and tether formation is observed. A critical onset force is identified where a tether spontaneously appears as a part of a second order shape transition. Further growth of a tether is followed by a detachment process which terminates at a finite force when a vesicle continuously unbinds from the substrate (Smith 2003b). Both critical forces, as well as all shape parameters, are calculated as a function of the reduced volume and the strength of adhesive potential. Analogous experimental study has been performed where a vertical magnetic tweezers are used in combination with micro-interferometric and confocal techniques to reproduce the same symmetry as in the theoretical investigation. Giant vesicles are bound to the substrate by numerous specific bonds formed between ligands and receptors incorporated into the vesicle and the substrate, respectively. Application of a constant force is inducing a new thermodynamic equilibrium of the system where the vesicle is partially unbound from the substrate (Goennenwein 2003). The shapes of vesicles are compared prior and during application of the force. Very good agreement is obtained, particularly in the middle-strength adhesion regime (Smith 2003c). References: 1. A.-S. Smith, E. Sackmann, U. Seifert: Effects of a pulling force on the shape of a bound vesicle, Europhys. Lett., 64, 2 (2003). 2. A.-S. Smith

  6. Use of employments on swimming in pulling in and restoration microcycles in the training process of the highly skilled sportsmen of the highly skilled heavy weight sambo wrestlers

    Directory of Open Access Journals (Sweden)

    Zakorko I.P.

    2013-01-01

    Full Text Available Expedience of the use of the sporting and health swimming is grounded in precontest preparation of the highly skilled sportsmen unarmed self-defence. 10 sportsmen took part in research (weight over 90 kg. Offered to recommendation on the use of swimming in renewal of sportsmen after the competition and trainings loadings. On employments, swimming was utillized a method crawl on a breast and by a method breast-stroke. Length of path of pool is 25 meters. The level of influence of trainings is set on swimming of different orientation on the general consisting of the sportsman unarmed self-defence of context of preparation and renewal during the specialized competition activity. It is recommended in training on swimming to utillize overcoming at full pelt of cutting-off 250 meters in the mode to 5 minutes (time of competition fight is in the fight of sambo-5 of minutes.

  7. 农业技术进步、新型城镇化与农村剩余劳动力转移--基于“推拉理论”和省际动态面板数据的实证研究%Agricultural Technology Process, New-urbanization and Transference of Redundant Rural Labor Force---Empirical Research Based on the “Push-pull Theory” and Inter-provincial Dynamic Panel Data

    Institute of Scientific and Technical Information of China (English)

    李斌; 吴书胜; 朱业

    2015-01-01

    本文以“推拉理论”为基础,构建包含农业技术进步、新型城镇化和农村剩余劳动力转移在内的计量模型,利用1998-2012年省际动态面板数据进行实证检验。研究结果表明,农业技术进步形成的“推力”和新型城镇化形成的“拉力”对促进农村剩余劳动力向城镇非农产业转移有显著作用,农业技术进步的“推力”由大到小依次为西部、东部和中部,而城镇化的“拉力”由大到小依次为中部、西部和东部。%This paper builds an econometric model which contains agricultural technology progress, new-urbanization and transference of redundant rural labor force, and makes an empirical test based on“push-pull theory” by using 1998-2012 an-nual inter-provincial dynamic panel data. National study shows the “push” from agricultural technology progress and the“pull” from new-urbanization have a significant promotion role for the shift of rural surplus labor to urban non-agricultural in-dustries. Sub-regional study shows that the“push” from agricultural technology progress in descending order is western, east-ern and central and the “pull” from new-urbanization in descending order is central, western and eastern.

  8. A Two-Magnet System to Push Therapeutic Nanoparticles

    Science.gov (United States)

    Shapiro, Benjamin; Dormer, Kenneth; Rutel, Isaac B.

    2010-01-01

    Magnetic fields can be used to direct magnetically susceptible nanoparticles to disease locations: to infections, blood clots, or tumors. Any single magnet always attracts (pulls) ferro- or para-magnetic particles towards it. External magnets have been used to pull therapeutics into tumors near the skin in animals and human clinical trials. Implanting magnetic materials into patients (a feasible approach in some cases) has been envisioned as a means of reaching deeper targets. Yet there are a number of clinical needs, ranging from treatments of the inner ear, to antibiotic-resistant skin infections and cardiac arrhythmias, which would benefit from an ability to magnetically “inject”, or push in, nanomedicines. We develop, analyze, and experimentally demonstrate a novel, simple, and effective arrangement of just two permanent magnets that can magnetically push particles. Such a system might treat diseases of the inner ear; diseases which intravenously injected or orally administered treatments cannot reach due to the blood-brain barrier. PMID:21243119

  9. Exploration of WANG Hao style over-the-table twist-pulling technique teaching and training%王皓式台内拧拉技术教学与训练探讨

    Institute of Scientific and Technical Information of China (English)

    熊志超

    2015-01-01

    The author analyzed such technical challenges in WANG Hao style over-the-table twist-pulling technique as “tilt the paddle somewhat forward, bend the wrist counterclockwise and raise the elbow joint outward to the limit”, and revealed that for a halfway player, the key to success in learning a new technique is to get over negative skill transformation. During teaching and training, the author designed a movement procedure in which psychology is combined with technique, a training method used to focus on inner attention by utilizing“the second signal sys-tem (language)”. Prior to twist-pulling, the player meditates this procedure (he/she can vigorously twist the ball only after he/she has bent the wrist counterclockwise to the limit and raised the elbow joint outward to the limit), so as to enhance his/her inner attention, constantly reduce, overcome or even eliminate the effect of negative skill transfor-mation, and ultimately master this new technique. However, as for a high performance player who has already mas-tered WANG Hao style over-the-table twist-pulling technique, he/she needs no inner attention, otherwise, it will damage his/her unconscious competence, obstruct the execution of skill automation, do no good but harm to skill exertion, which should be adequately noted by various coaches and players.%对王皓式台内拧拉技术难点“握拍压得较前倾,手腕沿逆时针方向弯曲大及肘关节向外抬高到极限的拧拉技法”进行了分析。结果表明:对半路出家运动员而言,学习新技术成功与否关键是要过技能负迁移关。在教学训练中设计了心理与技术相结合的动作程序,利用“第二信号系统”(语言)来集中内在注意力的训练方法。在拧拉前默念此程序(“手腕沿逆时针方向弯曲至极限,肘关节向外抬高至极限”,才能发力拧。)来提高内在注意力,不断减轻、克服甚至消除技能负迁移的影响,最终才能掌握

  10. Choices of Destination for Transnational Higher Education: "Pull" Factors in an Asia Pacific Market

    Science.gov (United States)

    Ahmad, Syed Zamberi; Buchanan, Frederick Robert

    2016-01-01

    Traditional assumptions favouring native English language countries in transnational higher education (TNHE) overlook experiences of international students in new emerging Asian education hubs. Specifically, there has been limited research relating to international students' choice for studying in Malaysia. Drawing from the "push-pull"…

  11. Choices of Destination for Transnational Higher Education: "Pull" Factors in an Asia Pacific Market

    Science.gov (United States)

    Ahmad, Syed Zamberi; Buchanan, Frederick Robert

    2016-01-01

    Traditional assumptions favouring native English language countries in transnational higher education (TNHE) overlook experiences of international students in new emerging Asian education hubs. Specifically, there has been limited research relating to international students' choice for studying in Malaysia. Drawing from the "push-pull"…

  12. 補償系三巻変成器を用いたpush-pull増幅回路の解析

    OpenAIRE

    西塚, 典生; 水沼, 充; 中津山, 幹男

    1985-01-01

    Abstract The compensated type three winding transformers have much balanced outputs and are suitable for the applications to push-pull amplifiers. We construct class B push-pull amplifiers with the compansated transformers as input and output transformers, and analyze frequency characteristics of the amplifiers. In the analyses, we use fundamental equations of distributed parameter theory of coupled three lines with winding ratio n:1:1 for the input and output transformers, and the hybrid π e...

  13. 補償系三巻変成器を用いたpush-pull増幅回路の解析

    OpenAIRE

    西塚, 典生; 水沼, 充; 中津山, 幹男

    1985-01-01

    Abstract The compensated type three winding transformers have much balanced outputs and are suitable for the applications to push-pull amplifiers. We construct class B push-pull amplifiers with the compansated transformers as input and output transformers, and analyze frequency characteristics of the amplifiers. In the analyses, we use fundamental equations of distributed parameter theory of coupled three lines with winding ratio n:1:1 for the input and output transformers, and the hybrid π e...

  14. Friction pull plug welding: dual chamfered plate hole

    Science.gov (United States)

    Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

    2001-01-01

    Friction Pull Plug Welding (FPPW) is a solid state repair process for defects up to one inch in length, only requiring single sided tooling (OSL) for usage on flight hardware. Early attempts with FPPW followed the matching plug/plate geometry precedence of the successful Friction Push Plug Welding program, however no defect free welds were achieved due to substantial plug necking and plug rotational stalling. The dual chamfered hole has eliminated plug rotational stalling, both upon initial plug/plate contact and during welding. Also, the necking of the heated plug metal under a tensile heating/forging load has been eliminated through the usage of the dual chamfered plate hole.

  15. PUSH technology in JAVA mobile application development application%PUSH 技术在JAVA移动应用程序开发中的应用

    Institute of Scientific and Technical Information of China (English)

    陈玉涛

    2013-01-01

    At present,traditional applications typically use the PULL mode,namely,to start the application by the user manual,and in some specific cases,the PULL method can not achieve some function we needed,then use PUSH to run the program,where the program starts running.This article main research is on the platform of J2ME,to make the mobile application program from the start to run through the PUSH registration mechanism.First,a brief introduction on PUSH technology,and then study in detail the process of using PUSH under the J2ME platform the registration system,the design of the MIDlet an application running on JAVA mobile phone to application verification of PUSH registration mechanism in practical procedures for the development of.%  目前传统的应用程序一般都采用 PULL 方式运行,即要通过用户手动来启动应用程序,而在一些特定情况下,PULL 方式并不能实现人们所需要的某些功能,这时要采用 PUSH 方式来运行程序,即让程序自动启动运行。文章主要研究的就是在 J2ME平台下,通过 PUSH 注册机制来使得移动应用程序自启动运行。首先对 PUSH 技术进行简单介绍,然后对于在 J2ME 平台下使用PUSH 注册机制的过程进行详细研究,最后开发设计了一个运行在 JAVA 手机上的 MIDlet 应用程序用来验证 PUSH 注册机制在实际程序开发中的应用。

  16. 移业就民:人口高流出地区的城镇化策略选择*--基于推拉模型的反力研究%Job Moving for Labors:Urbanization Strategy in Labor-losing Regions:Based on Counterforce Analysis of Push-and-pull Model

    Institute of Scientific and Technical Information of China (English)

    钟睿; 张立

    2014-01-01

    通过跨区域的移民来解决本地农村剩余劳动力的就业,是我国城镇化发展的主要路径之一。人口的区域流动为流出地和流入地的经济社会发展都做出了贡献,但是近年来我国大部分地区出现了民工荒和招工难等现象,反映出人口结构和人口迁移的新变化。在宏观分析的基础上,结合若干地区的社会调研,以推拉模型作为研究框架,分析论证了人口流入地的“拉力”变化和人口流出地的“推力”变化。与城市拉力相对应,人口流入地的反推力在逐渐加大;与农村推力相对应,人口流出地的反拉力也在加强。顺应当下推力和拉力的双向变化,指出人口高流出地区在引导农村剩余劳动力外出务工的同时,也要积极通过产业的导入来顺应本地的人口结构,提高本地人口就业,即“移业就民”。最后,结合国家新型城镇化规划提出了若干的延伸探讨。%Seeking job opportunities in different regions for rural surplus labors is one of the paths of urbanization in labor-losing regions. Inter-regional migration contributes to economic and social development in labor-losing regions as well as labor-gaining regions, but in recent years the phenomenon of labor shortage appearing in eastern regions indicates new trends of population structure and migration. This paper, combining with macro statistical data and field surveys, imports push-and-pul model as an analysis framework and explores changes of pul factors from labor-gaining regions and changes of push factors from labor-losing regions. It finds that both counter-pul force from labor-gaining regions and counter-push force from labor-losing regions are increasing. Therefore, this paper, to echo such changes, points out that the labor-losing regions should import industries adapting local population structure when they steer labors migrating out for jobs. That is to say, the orientation should be

  17. 基于“推一拉”理论的农村剩余劳动力回流现象分析——以黑龙江省为例%Based on Push - pull Back the Theory of the Phenomenon of Rural Surplas labor -A Case of Heilongjiang Province

    Institute of Scientific and Technical Information of China (English)

    王炜; 许幸莲

    2011-01-01

    中国农村剩余劳动力回流自1997年以后出现,到2011年初更趋明显。在对农村剩余劳动力回流现象的积极和消极影响进行分析的基础上,以农业大省黑龙江省为例,运用“推一拉”理论对农村剩余劳动力回流现象做出了深层次分析,并指出解决农村剩余劳动力回流问题的相应对策措施。%Since 1997 the backflow of rural surplus labors has been appeared and this phenomenon became more apparent in the beginning of 2011.On the basis of analysis on the positive and negative effect of the backflow of rural surplus labors,taking the agriculture in Heilonjiang Province for instance,the paper make a deep analysis on the phenomenon of the baekflow of rural surplus labors exerting "Pull and Push" theory and point out the related countermeasure to solve the issue of haekflow of rural surplus labors.

  18. The great carbon push-pull: where science is pushing and policy is pulling the official forest carbon inventory of the US

    Science.gov (United States)

    C.W. Woodall; G.M. Domke; J. Coulston; M.B. Russell; J.A. Smith; C.H. Perry; S. Healey; A. Gray

    2015-01-01

    A national system of field inventory plots (FIA) is the primary data source for the annual assessment of US forest carbon (C) stocks and stock-change to meet reporting requirements under the United Nations Framework Convention on Climate Change (UNFCCC). The inventory data and their role in national carbon reporting continue to evolve. The framework of the previous C...

  19. Pushing Personhood into Place

    DEFF Research Database (Denmark)

    Bidwell, Nicola J.; Winschiers-Theophilus, Heike; Kapuire, Gereon K.

    2011-01-01

    about personhood, community and place. We adopt a critical attitude towards assumptions about spatial, temporal and social logics and literacies to promote a design sensitivity to local experiences of locations. This motivates us to emphasize connections, not points, and the bodily absorption...... for generations; but technology-use can inadvertently displace knowledge for communities with knowledge traditions that differ from those of technology-design. Devices which are sensitive to users' locations, combined with platforms for social networking and user-generated-content, offer intriguing opportunities...... of location and social relations. We discuss designs that emulate the way participants identify social convergence to orient information and use voice, gesture and movement to push locations into this dialogic. Representations must coalesce socialrelational and topokinetic, rather than topographic, spaces. We...

  20. Motion planning with pull moves

    CERN Document Server

    Ritt, Marcus

    2010-01-01

    It is well known that Sokoban is PSPACE-complete (Culberson 1998) and several of its variants are NP-hard (Demaine et al. 2003). In this paper we prove the NP-hardness of some variants of Sokoban where the warehouse keeper can only pull boxes.

  1. The NASA technology push towards future space mission systems

    Science.gov (United States)

    Sadin, Stanley R.; Povinelli, Frederick P.; Rosen, Robert

    1988-01-01

    As a result of the new Space Policy, the NASA technology program has been called upon to a provide a solid base of national capabilities and talent to serve NASA's civil space program, commercial, and other space sector interests. This paper describes the new technology program structure and its characteristics, traces its origin and evolution, and projects the likely near- and far-term strategic steps. It addresses the alternative 'push-pull' approaches to technology development, the readiness levels to which the technology needs to be developed for effective technology transfer, and the focused technology programs currently being implemented to satisfy the needs of future space systems.

  2. Pull factors of Finland and voluntary work

    OpenAIRE

    Jurvakainen, Janika

    2016-01-01

    This thesis studies pull factors of Finland and voluntary work. The aim of this study is to understand the pull factors of Finland from the perspective of young travelers. Which pull factors attract to choose Finland as their destination? In addition, which pull factors attract young travelers to participate in international voluntary work? The commissioner of this thesis is Allianssi Youth Exchange. The thesis is research-based and includes a quantitative Webropol survey and some qualit...

  3. Attainment and retention of force moderation following laparoscopic resection training with visual force feedback.

    Science.gov (United States)

    Hernandez, Rafael; Onar-Thomas, Arzu; Travascio, Francesco; Asfour, Shihab

    2017-04-14

    Laparoscopic training with visual force feedback can lead to immediate improvements in force moderation. However, the long-term retention of this kind of learning and its potential decay are yet unclear. A laparoscopic resection task and force sensing apparatus were designed to assess the benefits of visual force feedback training. Twenty-two male university students with no previous experience in laparoscopy underwent relevant FLS proficiency training. Participants were randomly assigned to either a control or treatment group. Both groups trained on the task for 2 weeks as follows: initial baseline, sixteen training trials, and post-test immediately after. The treatment group had visual force feedback during training, whereas the control group did not. Participants then performed four weekly test trials to assess long-term retention of training. Outcomes recorded were maximum pulling and pushing forces, completion time, and rated task difficulty. Extreme maximum pulling force values were tapered throughout both the training and retention periods. Average maximum pushing forces were significantly lowered towards the end of training and during retention period. No significant decay of applied force learning was found during the 4-week retention period. Completion time and rated task difficulty were higher during training, but results indicate that the difference eventually fades during the retention period. Significant differences in aptitude across participants were found. Visual force feedback training improves on certain aspects of force moderation in a laparoscopic resection task. Results suggest that with enough training there is no significant decay of learning within the first month of the retention period. It is essential to account for differences in aptitude between individuals in this type of longitudinal research. This study shows how an inexpensive force measuring system can be used with an FLS Trainer System after some retrofitting. Surgical

  4. The Acute Potentiating Effects of Heavy Sled Pulls on Sprint Performance.

    Science.gov (United States)

    Winwood, Paul W; Posthumus, Logan R; Cronin, John B; Keogh, Justin W L

    2016-05-01

    This study examined the acute potentiating effects of heavy sprint-style sled pulls on sprint performance. Twenty-two experienced resistance-trained rugby athletes performed 2 heavy sprint-style sled pull training protocols on separate occasions using a randomized, crossover, and counterbalanced design. The protocols consisted of 2-baseline 15 m sprints followed by 15 m sprints at 4, 8, and 12 minutes after completing 15 and 7.5 m heavy sled pulls with loads of 75 and 150% body mass (respectively). A significantly faster (p ≤ 0.05) 15 m sprint time was observed at 12 minutes for the 75% body mass load. Small nonsignificant improvements (effect size [ES] = 0.22-0.33) in 5, 10, and 15 m sprint times were observed at 8 and 12 minutes after the 75% body mass sled pull. No significant changes were observed for any sprint time after the 150% body mass sled pull. Significant differences in the percentage of change in sprint times between the 2 sled pull conditions were observed at 4 (ES = 0.44-0.52), 8 (ES = 0.59), and 12 minutes (ES = 0.64). It would seem that the 75% body mass sled pull can be an effective preload stimulus for improving subsequent sprint performance provided that adequate recovery (8-12 minutes) is allowed. Practitioners should be advised that prescription of training load based on decrement in sprint velocity may be the best approach to determine loading for athletes.

  5. Electromyographic comparison of traditional and suspension push-ups.

    Science.gov (United States)

    Snarr, Ronald L; Esco, Michael R

    2013-12-18

    There is very limited scientific data concerning suspension training. The purpose of this investigation was to compare the electromyographic activity of the pectoralis major, anterior deltoid, and triceps brachii between a suspension push-up and traditional push-up. Twenty-one apparently healthy men (n = 15, age = 25.93 ± 3.67 years) and women (n = 6, age = 23.5 ± 1.97 years) volunteered to participate in this study. All subjects performed four repetitions of a suspension push-up and a traditional push-up where the order of the exercises was randomized. The mean peak and normalized electromyography of the pectoralis major, anterior deltoid, and triceps brachii were compared across the two exercises. Suspension push-ups elicited the following electromyographic values: pectoralis major (3.08 ± 1.13 mV, 69.54 ± 27.6 %MVC), anterior deltoid (5.08 ± 1.55 mV, 81.13 ± 17.77 %MVC), and triceps brachii (5.11 ± 1.97 mV, 105.83 ± 18.54 %MVC). The electromyographic activities during the traditional push-up were as follows: pectoralis major (2.66 ± 1.05 mV, 63.62 ± 16.4 %MVC), anterior deltoid (4.01 ± 1.27 mV, 58.91 ± 20.3 %MVC), and triceps brachii (3.91 ± 1.36 mV, 74.32 ± 16.9 %MVC). The mean peak and normalized electromyographic values were significantly higher for all 3 muscles during the suspension push-up compared to the traditional push-up (p < 0.05). This study suggests that the suspension push-up elicited a greater activation of pectoralis major, anterior deltoid, and triceps brachii when compared to a traditional push-up. Therefore, suspension push-ups may be considered an advanced variation of a traditional push-up when a greater challenge is warranted.

  6. Push-up motion analysis for patients with SCIs; Sekizui sonshosha no push up dosa bunseki

    Energy Technology Data Exchange (ETDEWEB)

    Tanimoto, Y.; Takechi, H. [Kibikogen Rehabilitation Center for Employment Injuries, Okayama (Japan); Nagahata, H.; Yamamoto, H. [Okayama Univ. (Japan)

    1998-11-30

    Push-up (PU) motion is indispensable motion in daily life for spinal cord injury (SCI) patients. The PU motion being the basic motion which a patient push his body up from sitting posture on the bed, a physical therapist must guide and train patients in correct method. In order to get dynamical data about PU motion a measurement instrument retaining a computer was made. A patients body being supported by both palms and both heels, these are placed on two scale platforms respectively. Each scale platform being mobile in back or forth and right or left directions, these movements and loads are inputted and are indicated with patterns. A patient, pushing-up his hips drawing his waist backward, maintains this posture for a while, and the height of hips is inputted. As direct measurement of the moments of shoulder points and hip joint is difficult, these are calculated by the Newton`s equation of motion in a computer. Differences of PU motion in every patients appearing most evidently in waveform pattern of Fx (power in back or forth direction), plenty of instructive hints for improvement of training effect were obtained. 11 refs., 8 figs.

  7. Power and impulse applied during push press exercise.

    Science.gov (United States)

    Lake, Jason P; Mundy, Peter D; Comfort, Paul

    2014-09-01

    The aim of this study was to quantify the load, which maximized peak and mean power, and impulse applied to these loads, during the push press and to compare them to equivalent jump squat data. Resistance-trained men performed 2 push press (n = 17; age: 25.4 ± 7.4 years; height: 183.4 ± 5 cm; body mass: 87 ± 15.6 kg) and jump squat (n = 8 of original 17; age: 28.7 ± 8.1 years; height: 184.3 ± 5.5 cm; mass: 98 ± 5.3 kg) singles with 10-90% of their push press and back squat 1 repetition maximum (1RM), respectively, in 10% 1RM increments while standing on a force platform. Push press peak and mean power was maximized with 75.3 ± 16.4 and 64.7 ± 20% 1RM, respectively, and impulses applied to these loads were 243 ± 29 N·s and 231 ± 36 N·s. Increasing and decreasing load, from the load that maximized peak and mean power, by 10 and 20% 1RM reduced peak and mean power by 6-15% (p ≤ 0.05). Push press and jump squat maximum peak power (7%, p = 0.08) and the impulse that was applied to the load that maximized peak (8%, p = 0.17) and mean (13%, p = 0.91) power were not significantly different, but push press maximum mean power was significantly greater than the jump squat equivalent (∼9.5%, p = 0.03). The mechanical demand of the push press is comparable with the jump squat and could provide a time-efficient combination of lower-body power and upper-body and trunk strength training.

  8. RACE pulls for shared control

    Science.gov (United States)

    Leahy, M. B., Jr.; Cassiday, B. K.

    1993-02-01

    Maintaining and supporting an aircraft fleet, in a climate of reduced manpower and financial resources, dictates effective utilization of robotics and automation technologies. To help develop a winning robotics and automation program the Air Force Logistics Command created the Robotics and Automation Center of Excellence (RACE). RACE is a command wide focal point. Race is an organic source of expertise to assist the Air Logistic Center (ALC) product directorates in improving process productivity through the judicious insertion of robotics and automation technologies. RACE is a champion for pulling emerging technologies into the aircraft logistic centers. One of those technology pulls is shared control. Small batch sizes, feature uncertainty, and varying work load conspire to make classic industrial robotic solutions impractical. One can view ALC process problems in the context of space robotics without the time delay. The ALC's will benefit greatly from the implementation of a common architecture that supports a range of control actions from fully autonomous to teleoperated. Working with national laboratories and private industry, we hope to transition shared control technology to the depot floor. This paper provides an overview of the RACE internal initiatives and customer support, with particular emphasis on production processes that will benefit from shared control technology.

  9. Station Program Note Pull Automation

    Science.gov (United States)

    Delgado, Ivan

    2016-01-01

    Upon commencement of my internship, I was in charge of maintaining the CoFR (Certificate of Flight Readiness) Tool. The tool acquires data from existing Excel workbooks on NASA's and Boeing's databases to create a new spreadsheet listing out all the potential safety concerns for upcoming flights and software transitions. Since the application was written in Visual Basic, I had to learn a new programming language and prepare to handle any malfunctions within the program. Shortly afterwards, I was given the assignment to automate the Station Program Note (SPN) Pull process. I developed an application, in Python, that generated a GUI (Graphical User Interface) that will be used by the International Space Station Safety & Mission Assurance team here at Johnson Space Center. The application will allow its users to download online files with the click of a button, import SPN's based on three different pulls, instantly manipulate and filter spreadsheets, and compare the three sources to determine which active SPN's (Station Program Notes) must be reviewed for any upcoming flights, missions, and/or software transitions. Initially, to perform the NASA SPN pull (one of three), I had created the program to allow the user to login to a secure webpage that stores data, input specific parameters, and retrieve the desired SPN's based on their inputs. However, to avoid any conflicts with sustainment, I altered it so that the user may login and download the NASA file independently. After the user has downloaded the file with the click of a button, I defined the program to check for any outdated or pre-existing files, for successful downloads, to acquire the spreadsheet, convert it from a text file to a comma separated file and finally into an Excel spreadsheet to be filtered and later scrutinized for specific SPN numbers. Once this file has been automatically manipulated to provide only the SPN numbers that are desired, they are stored in a global variable, shown on the GUI, and

  10. Ultrasound-guided percutaneous "push-introducer" gastrostomy is a valuable method for accessing the gastrointestinal tract

    Directory of Open Access Journals (Sweden)

    Stanislaw Klek

    2014-02-01

    Full Text Available Percutaneous endoscopic gastrostomy (PEG is the mosteffective and least invasive method for enteral nutrition (EN. The most common system for PEG is the 'pull' technique, which. It is not available in case endoscopy cannot be performed. The 'push' technique may be an option if effective identification of the abdominal structures can be achieved. X-ray or ultrasonography can be used for that purpose. The aim was to assess the clinical value of ultrasound-guided 'push' gastrostomy. A retrospective analysis of eleven patients (6 F, 5 M, mean age 65.1 including the procedure itself, complication rate, and cost was conducted. In all eleven patients the surgery was successful, and EN was introduced 4-6 hours afterwards. Complications included pain requiring removal of a supporting stitch (n = 1 and balloon deflation (n = 1. All patients were successfully fed enterally. Ultrasound-guided 'push' technique gastrostomy should become a method of choice if the 'pull' method is unavailable.

  11. Molecular junctions: can pulling influence optical controllability?

    Science.gov (United States)

    Parker, Shane M; Smeu, Manuel; Franco, Ignacio; Ratner, Mark A; Seideman, Tamar

    2014-08-13

    We suggest the combination of single molecule pulling and optical control as a way to enhance control over the electron transport characteristics of a molecular junction. We demonstrate using a model junction consisting of biphenyl-dithiol coupled to gold contacts. The junction is pulled while optically manipulating the dihedral angle between the two rings. Quantum dynamics simulations show that molecular pulling enhances the degree of control over the dihedral angle and hence over the transport properties.

  12. From structural push to chain migration: notes on the persistence of migration to Ciudad Juarez, Mexico.

    Science.gov (United States)

    Zoomers, E B

    1986-01-01

    "Spatial differentiation in regional welfare is often assumed to be one of the most important explanatory factors in individual migration behaviour. By the weight of 'push' against 'pull', migrants walk in step with the unequal distribution of socio-economic opportunities. In the case of Ciudad Juarez [Mexico], these 'structural factors' only appear to have determined migration in its first stages; especially recently 'non-structural' factors seem to be at the root of the ever-increasing process."

  13. Exposure to ultrafine particles and black carbon in diesel-powered commuter trains

    Science.gov (United States)

    Jeong, Cheol-Heon; Traub, Alison; Evans, Greg J.

    2017-04-01

    Ultrafine particle (UFP), black carbon (BC) and lung deposited surface area (LDSA) concentrations measured during 43 trips on diesel-powered commuter trains revealed elevated exposures under some conditions. When the passenger coaches were pulled by a locomotive, the geometric mean concentrations of UFP, LDSA, and BC were 18, 10, and 6 times higher than the exposure levels when the locomotive pushed the coaches, respectively. In addition, UFP, LDSA, and BC concentrations in pull-trains were 5, 3, and 4 times higher than concentrations measured while walking on city sidewalks, respectively. Exposure to these pollutants was most elevated in the coach located closest to the locomotive: geometric means were 126,000 # cm-3 for UFP, 249 μm2 cm-3 for LDSA, and 17,800 ng m-3 of BC; these concentrations are much higher than those previously reported for other modes of public transportation. Markedly high levels of diesel exhaust are present in passenger trains powered by diesel locomotives operated in pull-mode. Thus, it is recommended that immediate steps be taken to evaluate, and where needed, mitigate exposure in diesel-powered passenger trains, both commuter and inter-city.

  14. Push-Pull Converter Fed Three-Phase Inverter for Residential and Motor Load

    Directory of Open Access Journals (Sweden)

    Samuel Rajesh Babu

    2015-06-01

    Full Text Available The proposed paper is an new approach for power conditioning of a PV (photo-voltaic cell array. The main objective is to investigate an approach to provide and improve the delivered electric energy by means of power conditioning structures with the use of alternative renewable resources (ARRs for remote rural residential or industrial non-linear loads. This approach employs a series-combined connected boost and buck boost DC-DC converter for power conditioning of the dc voltage provided by a photo-voltaic array. The input voltage to the combined converters is 100 V provided from two series connected PV cells, which is converted and increased to 200 V at the dc output voltage. Series-combined connected boost and buck-boost DC-DC converters operate  alternatively. This helps to reduce the input ripple current and provide the required 400 Vdc on a sinusoidal PWM three-phase inverter. Analysis of the two series-combined DC-DC converters is presented along with simulation results. Simulations of the series-combined DC-DC converters are presented with an output DC voltage of 200 V and a maximum output load of Po = 600 W.

  15. Oncogenic Ras pushes (and pulls) cell cycle progression through ERK activation.

    Science.gov (United States)

    Campbell, Paul M

    2014-01-01

    The Ras-Raf-MEK-ERK signaling cascade is capable of channeling a wide variety of extracellular signals into control of cell proliferation, differentiation, senescence, and death. Because aberrant regulation at all steps of this signaling axis is observed in cancer, it remains an area of great interest in the field of tumor biology. Here we present evidence of the intricate and delicate levels of control of this pathway as it pertains to cell cycle regulation and illustrate how this control is not simply a rheostat.

  16. Spatial repellents and attractants as components of a "push-pull" management strategy

    Science.gov (United States)

    This presentation was an overview of research efforts being conducted by the Mosquito and Fly Research Unit (MFRU) of the United States Department of Agriculture (USDA), Center for Medical and Veterinary Entomology (CMAVE) located in Gainesville, Florida, to develop innovative population management...

  17. What is Happening in Supply Chain Management? From Push to Pull through Best Value Thinking

    NARCIS (Netherlands)

    Santema, S.C.

    2011-01-01

    In this paper we take a closer look at developments in supply management. The main change in this discipline seems to be (2011) that cooperation and risk management are taking over the classical silo based way of looking at business. Companies start to learn that transactions block the profits

  18. Reversing Early Retirement in Advanced Welfare Economies A Paradigm Shift to Overcome Push and Pull Factors

    Directory of Open Access Journals (Sweden)

    Dr. Bernhard Ebbinghaus

    2013-12-01

    Full Text Available Recent reform efforts of advanced welfare states have attempted to reverse trends in early retirement and increase the statutory retirement age. This paradigm shift often occurred against the protest of unions, fi rms and their employees. As a consequence of expanding welfare states and as response to economic challenges since the 1970s early exit from work has become a widespread practice. Early retirement has been part of Continental Europe’s welfare without work problem, while the Scandinavian welfare states, the Anglophone liberal economies and the Japanese welfare society were able to maintain higher levels of employment for older workers. Since the 1990s, an international consensus to reverse early exit from work emerged among international organisations and national policy experts. Based on a comparative historical analysis of selected OECD countries, this study analyses the cross-national variations in the institutionalisation of early exit regimes and its recent reversal using macro-indictors on early exit trends and stylised information on institutional arrangements. Comparing the interaction of social policy and economic institutions, it reviews the cross-national differences in welfare state “pull” and economic “push” factors that have contributed to early exit from work and discusses the likely impact of welfare retrenchment and assesses the importance of “retention” factors such as activation policies for decreasing early exit from work.

  19. Field Evaluation of a Push-Pull System to Reduce Malaria Transmission

    NARCIS (Netherlands)

    Menger, D.J.; Omusula, P.; Holdinga, M.R.; Homan, T.; Carreira, A.S.; Vandendaele, P.; Derycke, J.L.; Mweresa, C.K.; Mukabana, W.R.; Loon, van J.J.A.; Takken, W.

    2015-01-01

    Malaria continues to place a disease burden on millions of people throughout the tropics, especially in sub-Saharan Africa. Although efforts to control mosquito populations and reduce human-vector contact, such as long-lasting insecticidal nets and indoor residual spraying, have led to significant d

  20. Pushing, pulling and trapping - Modes of motor protein supported protein translocation

    NARCIS (Netherlands)

    Tomkiewicz, Danuta; Nouwen, Nico; Driessen, Arnold J. M.

    2007-01-01

    Protein translocation across the cellular membranes is an ubiquitous and crucial activity of cells. This process is mediated by translocases that consist of a protein conducting channel and an associated motor protein. Motor proteins interact with protein substrates and utilize the free energy of

  1. Reindeer Herders in Finland: Pulled to Community-based Entrepreneurship & Pushed to Individualistic Firms'

    OpenAIRE

    Dana, Leo; Riseth, Jan Age

    2011-01-01

    Content analysis of interviews conducted with reindeer herders ‒ referred to as reindeer husbandry entrepreneurs, by the Reindeer Herders’ Association ‒ from two ethnic communities in Finland reveals that participants who identified themselves as ethnic Finns viewed their self-employment as an individualistic form of entrepreneurship and they focused their discussion on matters related to financial capital and profit. In contrast, Sámi respondents claimed that the causal varia...

  2. Push-pull tactics to disrupt the host-seeking behaviour of malaria mosquitoes

    NARCIS (Netherlands)

    Menger, D.J.

    2015-01-01

    Malaria remains a major health burden, especially in sub-Saharan Africa. The efficacy of the main vector control tools, insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS), is compromised by the development of physiological and behavioural resistance in the target mosquito species

  3. What is Happening in Supply Chain Management? From Push to Pull through Best Value Thinking

    NARCIS (Netherlands)

    Santema, S.C.

    2011-01-01

    In this paper we take a closer look at developments in supply management. The main change in this discipline seems to be (2011) that cooperation and risk management are taking over the classical silo based way of looking at business. Companies start to learn that transactions block the profits throu

  4. Third-order nonlinear optical response of push-pull azobenzene polymers

    Science.gov (United States)

    Papagiannouli, I.; Iliopoulos, K.; Gindre, D.; Sahraoui, B.; Krupka, O.; Smokal, V.; Kolendo, A.; Couris, S.

    2012-12-01

    The nonlinear optical response of a series of azo-containing side-chain polymers is investigated using Z-scan technique, employing 35 ps and 4 ns laser pulses, at 532 nm. The systems were found to exhibit strong nonlinear optical response, dominated by nonlinear refraction. In all cases, the nonlinear absorption and refraction have been determined and are compared with those of disperse red 1 considered as reference. The corresponding third-order susceptibilities χ(3) were determined to be as large as 10-7 and 10-5 esu under ps and ns laser excitation, respectively. Finally, the results are discussed and compared with other reported data.

  5. Push and Pull in the Classroom: Competition, Gender and the Neoliberal Subject

    Science.gov (United States)

    Wilkins, Andrew

    2012-01-01

    In this paper I explore how learning strategies based on competition and zero-sum thinking are inscribed into the dynamics of classroom interaction shaping relations between high-achieving pupils, and link elements of these practices to market trends in British education policy discourse. A detour through the politico-historical negotiations…

  6. Push-pull tactics to disrupt the host-seeking behaviour of malaria mosquitoes

    NARCIS (Netherlands)

    Menger, D.J.

    2015-01-01

    Malaria remains a major health burden, especially in sub-Saharan Africa. The efficacy of the main vector control tools, insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS), is compromised by the development of physiological and behavioural resistance in the target mosquito species

  7. Field Evaluation of a Push-Pull System to Reduce Malaria Transmission

    NARCIS (Netherlands)

    Menger, D.J.; Omusula, P.; Holdinga, M.R.; Homan, T.; Carreira, A.S.; Vandendaele, P.; Derycke, J.L.; Mweresa, C.K.; Mukabana, W.R.; Loon, van J.J.A.; Takken, W.

    2015-01-01

    Malaria continues to place a disease burden on millions of people throughout the tropics, especially in sub-Saharan Africa. Although efforts to control mosquito populations and reduce human-vector contact, such as long-lasting insecticidal nets and indoor residual spraying, have led to significant

  8. The antagonism of push and pull strategies, and the current funding campaigns to fight orphan diseases.

    Science.gov (United States)

    Leoni, Patrick

    2011-01-01

    We argue that an increase in investments in R&D for innovative treatments to eradicate neglected diseases in developing countries leads to a rational decrease in investments in available treatment technologies. In a formal model where the government of a developing country seeks to optimally allocate public resources, we show that the higher the odds of appearance of an innovative treatment, as occurring when investments in R&D increase, the lower the optimal provision of current treatments and other health expenditures. We also show that this phenomenon is aggravated when the opportunity cost of investments in current treatments increases. This implies that welfare in developing countries deteriorates as innovative treatments are more likely to become available. We also describe an insurance scheme that remedies these issues, and that leads to Pareto-optimal allocations regardless of the investment level in R&D for innovative treatments. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Series and parallel connection of ZVS-ZCS push-pull DC/DC converter module

    National Research Council Canada - National Science Library

    Chu, Ching-Lung; Chien, Chin-Nan

    2012-01-01

    ..., the input current of the modular converter increases as the output voltage decreases. A standardized modular converter can be connected either in series or in parallel to increase its rated capacity...

  10. The Push and the Pull: Deficit Models, Ruby Payne, and Becoming a "Warm Demander"

    Science.gov (United States)

    Boucher, Michael L.; Helfenbein, Robert J.

    2015-01-01

    Despite a caveat at the end of "A Framework for Understanding Poverty"(1996/2005), Ruby Payne's deficit model has led researchers to criticize her effect on White pre-service teaching students (Smiley and Helfenbein in "Multicult Perspect" 13(1):5-15, 2011; Gorski in "Educ Leadersh" 65:32-36, 2008a, "Equity…

  11. Theoretical study on oligothiophene N-succinimidyl esters: size and push-pull effects.

    Science.gov (United States)

    Piacenza, M; Zambianchi, M; Barbarella, G; Gigli, G; Della Sala, F

    2008-09-21

    We report a theoretical study on the optical properties of bithiophene and terthiophene N-succinimidyl esters, which have been functionalized with a methylsulfanyl group in the alpha or the beta positions. Time-dependent density functional theory (TD-DFT) and approximate coupled-cluster singles and doubles with the resolution of identity technique (RI-CC2) calculations have been performed in the ground and excited states. The RI-CC2 results for absorption and fluorescence energies are in better qualitative agreement with experiments, whereas TD-DFT does not correctly describe the higher energy part of the absorption spectra of beta-substituted bithiophenes, due to the presence of charge-transfer states. Systems functionalized at the alpha position show a large red-shift of the main absorption and fluorescence band and a larger Stokes-shift compared to the unsubstituted species. These effects are in most cases less pronounced for the beta-substituted structures. In particular, we found that the Stokes-shift of the alpha-substituted structures is larger than the one of the beta-substituted species due to a more planar orientation of the methylsulfanyl group with respect to the neighbouring thiophene in the excited state.

  12. A DFT study on NLO response of push-pull hybrid porphyrin-polyoxometalate complexes

    Science.gov (United States)

    Yao, Chan; Hu, Bo; Wang, Qingwei; Song, Ping; Su, Zhongmin

    2014-06-01

    Density functional theory (DFT) calculations were carried out to investigate the second-order nonlinear optical (NLO) properties of a series of proposed porphyrin-polyoxometalate-based complexes related to [5-(3,5-dimethyl-4-hexamolybdate amino-phenyl-ethynyl)-15-(4-nitrophenyl-ethynyl)porphinato]zinc(II) which have donor-π conjugated bridge-acceptor (D-π-A) configurations. Our calculations show that these species possess considerably large molecular total second-order polarizability (β0), ˜2000 × 10-30 esu. Furthermore, it can be seen that {W6O18} exhibits stronger electron-donating ability than {Mo6O18}. And two-dimensional (2D) system with A-π-D-π-A structure might be a promising candidate for NLO materials based on the large β0 (4583.5 × 10-30 esu) and in-plane nonlinear anisotropy.

  13. The Push and Pull of the World: How Experience Animates Practice

    Science.gov (United States)

    Wagenaar, Hendrik; Cook, S. D. Noam

    2011-01-01

    A refreshed and expanded understanding of experience can contribute to a relevant reassessment of the nature of practice and its relationship with knowledge and context. We characterise experience as essentially transactional, as entailing constitutive interaction with the elements of the social, institutional and physical world. It is within this…

  14. Price Transmission Mechanisms among Disaggregated Processing Stages of Food: Demand-Pull or Cost-Push?

    OpenAIRE

    Kwon, Dae-Heum; Koo, Won W.

    2009-01-01

    The recent concurrent surges of food and commodity prices renew the debate on the causal directions between producer and consumer prices. To address this issue, we utilize the stage of processing system incorporating retail stage beyond crude, intermediate, and finished processing stages of food and employ the method proposed by Toda and Yamamoto (1995) and Dolado and Lütkepohl (1996) of Granger causality tests. The overall results show that consistent with theory of derived demand, the deman...

  15. Push-pull theory: using mechanotransduction to achieve tissue perfusion and wound healing in complex cases.

    Science.gov (United States)

    Ennis, William J; Meneses, Patricio; Borhani, Martin

    2008-11-01

    Wound healing has evolved from gauze therapy to the use of proteomics, gene therapy, and cellular-based therapies in the short time span of 45 years. Education for health care providers has not kept pace with the logarithmic acceleration in technology development and treatment options. A patient with a non-healing wound requires a comprehensive work-up, including a focus on six primary points of interest. These points include the status of tissue perfusion, role of bacterial contamination, pressure applied to the tissue, the immune status of the host, co-morbid medical conditions including the patient's psychosocial status, and lastly, the status of the wound itself. Even after re-establishing macrovascular flow, many wounds either fail to improve or paradoxically worsen. Potential mechanisms for these unexpected findings include reperfusion injury, no-reflow, and the presence of stunned/hibernating tissue. Using the concept of mechanotransduction, the clinician can simulate normal pulsatile blood flow and re-establish adequate microvascular perfusion. Treatment regimens may include negative pressure therapy, electrical stimulation, ultrasound therapy, and other energy-based modalities.

  16. Beyond "Push" and "Pull" Explanations, Asian-Indian Graduate Students in the United States.

    Science.gov (United States)

    Menon, Sarath; Carspecken, Phil

    The findings of a qualitative study of migrant graduate students from India who now reside in the United State is presented. Through a series of interviews with students attending three U.S. universities, a model of the migratory process was developed. Much recent work on migratory theory has focused on the lack of opportunities in the students'…

  17. Large First Hyperpolarizabilities in Push-Pull Polyenes by Tuning Bond Length Alternation and Aromaticity

    Science.gov (United States)

    Marder, S. R.; Tiemann, B. G.; Friedli, A. C.; Cheng, L. -T.; Blanchard-Desce, M.

    1993-01-01

    Conjugated organic compounds with 3-phenyl-5-isoxazolone, or N, N'-diethylthiobarbituric acid acceptors have large first molecular hyperpolarizabilities in comparison to compounds with 4-nitrophenyl acceptors as measured by electric feld induced second harmonic generation, (EFISH), in chloroform, with 1.907 micron fundamental radiation.

  18. Korean Sojourners in the Deep South: The Push/Pull Dynamics of Immigration

    Science.gov (United States)

    Lynn, C. Allen; Lee, Sun-A.

    2013-01-01

    Asians are now the fastest growing ethnic group in the United States. And although disproportionately more likely to live in Western states, some are settling in nontraditional host communities. Focusing on one such instance in southeast Georgia, the present ethnographic case study considers a poultry processing plant's decision to recruit…

  19. Promoting healthy dietary behaviour through personalised nutrition: technology push or technology pull?

    NARCIS (Netherlands)

    Stewart-Knox, B.; Rankin, A.; Kuznesof, S.; Poínhos, R.; Vaz de Almeida, M.D.; Fischer, A.R.H.; Frewer, L.J.

    2015-01-01

    The notion of educating the public through generic healthy eating messages has pervaded dietary health promotion efforts over the years and continues to do so through various media, despite little evidence for any enduring impact upon eating behaviour. There is growing evidence, however, that

  20. Push-Pull Tests for Evaluating the Aerobic Cometabolism of Chlorinated Aliphatic Hydrocarbons

    Science.gov (United States)

    2005-04-13

    measurement using the same procedure. The reference sample consists of oxygen saturated distilled water , which was 24 prepared by sparging a 1 L bottle ...the Toluene-oxidizing Bacterium, Burkholderia cepacia G4. Ph.D. Thesis, Oregon State University, Corvallis, Oregon. Yeager, C. M. 2002. Inactivation...plastic tanks and carboys to hold prepared test solutions, and standard groundwater sampling equipment. The injected test solution consists of water

  1. Push, pull, and reverse: self-interest, responsibility, and the global health care worker shortage.

    Science.gov (United States)

    Kirby, Katherine E; Siplon, Patricia

    2012-06-01

    The world is suffering from a dearth of health care workers, and sub-Saharan Africa, an area of great need, is experiencing the worst shortage. Developed countries are making the problem worse by luring health care workers away from the countries that need them most, while developing countries do not have the resources to stem the flow or even replace those lost. Postmodern philosopher Emmanuel Levinas offers a unique ethical framework that is helpful in assessing both the irresponsibility inherent in the current global health care situation and the responsibility and obligation held by the stakeholders involved in this global crisis. Drawing on Levinas' exploration of individual freedom and self-pursuit, infinite responsibility for the Other, and the potential emergence of a just community, we demonstrate its effectiveness in explaining the health care worker crisis, and we argue in favor of a variety of policy and development assistance measures that are grounded in an orientation of non-indifference toward Others.

  2. Nonlinear optical properties of porphyrins compounds based on Cobalt and Zinc push-pull type

    OpenAIRE

    Chniti, Meherzia

    2016-01-01

    This study deals with the third-order nonlinear optical properties (NL) of tetraphenylporphyrins and some of its metallic derivatives (Zn, Co) dissolved in chlorobenzene. The solutions were exposed to a laser emitting at 1064 nm, 532 nm and 355 nm in the picosecond regime ( ≈ 10 ps) using D4σ-Z-scan method in a 4f setup and a new technique called Dark-Field Zscan. The latter provides to be very reliable for the direct determination of the nonlinear refractive signal in the presence of a stron...

  3. Promoting healthy dietary behaviour through personalised nutrition: technology push or technology pull?

    NARCIS (Netherlands)

    Stewart-Knox, B.; Rankin, A.; Kuznesof, S.; Poínhos, R.; Vaz de Almeida, M.D.; Fischer, A.R.H.; Frewer, L.J.

    2015-01-01

    The notion of educating the public through generic healthy eating messages has pervaded dietary health promotion efforts over the years and continues to do so through various media, despite little evidence for any enduring impact upon eating behaviour. There is growing evidence, however, that tailor

  4. Price Transmission Mechanism among Disaggregated Processing Stages of Food: Demand-Pull or Cost-Push?

    OpenAIRE

    Kwon, Dae-Heum; Koo, Won W.

    2013-01-01

    The recent concurrent surges of food and commodity prices renew the debate on the causal directions between producer and consumer prices. To address this issue, we utilize the stage of processing system incorporating retail stage beyond crude, intermediate, and finished processing stages of food and employ the method proposed by Toda and Yamamoto (1995) and Dolado and Lütkepohl (1996) of Granger causality tests. The overall results show that consistent with theory of derived demand, the deman...

  5. Circulating East to East: Understanding the Push-Pull Factors of Chinese Students Studying in Korea

    Science.gov (United States)

    Lee, Se Woong

    2017-01-01

    Every year, substantial numbers of students choose to study abroad, and China is one of the largest exporters of international students. Interestingly, instead of choosing English-speaking countries, increasingly more Chinese students are choosing nearby Asian countries as their destination to study abroad, particularly Korea. Despite this…

  6. Promoting healthy dietary behaviour through personalised nutrition: technology push or technology pull?

    Science.gov (United States)

    Stewart-Knox, Barbara; Rankin, Audrey; Kuznesof, Sharron; Poínhos, Rui; Vaz de Almeida, Maria Daniel; Fischer, Arnout; Frewer, Lynn J

    2015-05-01

    The notion of educating the public through generic healthy eating messages has pervaded dietary health promotion efforts over the years and continues to do so through various media, despite little evidence for any enduring impact upon eating behaviour. There is growing evidence, however, that tailored interventions such as those that could be delivered online can be effective in bringing about healthy dietary behaviour change. The present paper brings together evidence from qualitative and quantitative studies that have considered the public perspective of genomics, nutrigenomics and personalised nutrition, including those conducted as part of the EU-funded Food4Me project. Such studies have consistently indicated that although the public hold positive views about nutrigenomics and personalised nutrition, they have reservations about the service providers' ability to ensure the secure handling of health data. Technological innovation has driven the concept of personalised nutrition forward and now a further technological leap is required to ensure the privacy of online service delivery systems and to protect data gathered in the process of designing personalised nutrition therapies.

  7. Synthesis, spectroscopy, and theoretical calculations for a series of push-pull [14]-pyridoannulenes.

    Science.gov (United States)

    Lauer, Matthew G; Leslie, James W; Mynar, Ashley; Stamper, Shelly A; Martinez, Anthony D; Bray, Adrian J; Negassi, Senai; McDonald, Kevin; Ferraris, Eric; Muzny, Aaron; McAvoy, Shawn; Miller, Christopher P; Walters, Keith A; Russell, Keith C; Wang, Evan; Nuez, Betsy; Parish, Carol

    2008-01-18

    Three new isomeric dipyridoannulenes were synthesized and characterized. These molecules possess differing conjugation pathways between the substituent alkoxy donating groups and the pyridyl acceptor groups. Optical absorption and emission properties of the dipyridoannulenes and their corresponding acyclic precursors were measured and correlated to structural differences and used to evaluate conjugation effectiveness and charge-transfer pathways. Optical properties of protonated dipyridoannulenes were also measured and found to be somewhat insensitive to the degree of protonation. Density functional studies of these systems at the B3LYP/6-31G* level provided insight into their stabilities, polarities, and quinoidal character. An analysis of the HOMO and LUMO molecular orbitals provided further information regarding charge-transfer behavior. These systems are good metal binding candidates, as the pyridine moiety can act as both an electron-acceptor and a site for metal coordination.

  8. Pull vs. Push: How OmniEarth Delivers Better Earth Observation Information to Subscribers

    Science.gov (United States)

    Fish, C.; Slagowski, S.; Dyrud, L.; Fentzke, J.; Hargis, B.; Steerman, M.

    2015-04-01

    Until very recently, the commercialization of Earth observation systems has largely occurred in two ways: either through the detuning of government satellites or the repurposing of NASA (or other science) data for commercial use. However, the convergence of cloud computing and low-cost satellites is enabling Earth observation companies to tailor observation data to specific markets. Now, underserved constituencies, such as agriculture and energy, can tap into Earth observation data that is provided at a cadence, resolution and cost that can have a real impact to their bottom line. To connect with these markets, OmniEarth fuses data from a variety of sources, synthesizes it into useful and valuable business information, and delivers it to customers via web or mobile interfaces. The "secret sauce" is no longer about having the highest resolution imagery, but rather it is about using that imagery - in conjunction with a number of other sources - to solve complex problems that require timely and contextual information about our dynamic and changing planet. OmniEarth improves subscribers' ability to visualize the world around them by enhancing their ability to see, analyze, and react to change in real time through a solutions-as-a-service platform.

  9. The push and pull of grief: Approach and avoidance in bereavement

    NARCIS (Netherlands)

    Maccallum, F.; Sawday, S.; Rinck, M.; Bryant, R.A.

    2015-01-01

    Background and objectives: Prolonged Grief (PG) is recognized as a post-bereavement syndrome that is associated with significant impairment. Although approach and avoidance tendencies have both been hypothesized to play key roles in maintaining PG symptoms, understanding of these relationships has

  10. Push and Pull in the Classroom: Competition, Gender and the Neoliberal Subject

    Science.gov (United States)

    Wilkins, Andrew

    2012-01-01

    In this paper I explore how learning strategies based on competition and zero-sum thinking are inscribed into the dynamics of classroom interaction shaping relations between high-achieving pupils, and link elements of these practices to market trends in British education policy discourse. A detour through the politico-historical negotiations…

  11. Field Evaluation of a Push-Pull System to Reduce Malaria Transmission

    NARCIS (Netherlands)

    Menger, D.J.; Omusula, P.; Holdinga, M.R.; Homan, T.; Carreira, A.S.; Vandendaele, P.; Derycke, J.L.; Mweresa, C.K.; Mukabana, W.R.; Loon, van J.J.A.; Takken, W.

    2015-01-01

    Malaria continues to place a disease burden on millions of people throughout the tropics, especially in sub-Saharan Africa. Although efforts to control mosquito populations and reduce human-vector contact, such as long-lasting insecticidal nets and indoor residual spraying, have led to significant d

  12. Gender differences when choosing school subjects: Parental push and career pull. Some tentative hypotheses

    Science.gov (United States)

    Dawson, Chris; O'Connor, Pam

    1991-12-01

    The literature has made us all aware of large gender differences in students' atttudes to science, in enrolment statistics in upper high school and tertiary level science courses, and in different spheres of employment. What have not been looked at in detail are the factors which are influential when students begin to make choices in early high school, choices which may well set them on a particular pathway from which it is difficult to turn. This preliminary study identifies factors which students in a Year 9 class believed were influential on the limited subject choices they had been able to make in Years 8 and 9, and the factors they believed would be most influential on choices to be made later in the school. In addition the students' views of science, of the separate sciences, and of their anticipated career patterns were sought. Several interesting findings were made which, if validated in further work, could lead to strategies which would support other approaches designed to reduce gender imbalances related to science.

  13. Electromyographical Comparison of a Traditional, Suspension Device, and Towel Pull-Up

    Directory of Open Access Journals (Sweden)

    Snarr Ronald L.

    2017-08-01

    Full Text Available Strengthening muscles of the back may have various implications for improving functions of daily living, aiding in the transfer of power in throwing, and assist in injury prevention of the shoulder complex. While several versions of the pull-up exist, there is currently no literature comparing their differences. The purpose of this investigation was to compare the electromyographical activity of the latissimus dorsi, posterior deltoid, middle trapezius, and biceps brachii while performing three variations of the pull-up. Resistance-trained men and women (n =15, age = 24.87 ± 6.52 years participated in this study by performing traditional pull-ups, suspension device pull-ups, and towel pull-ups in a randomized fashion. Each pull-up was performed for three repetitions with a 1.5 bi-acromial grip-width for each participant. Normalized (%MVC electromyographical values were recorded for each muscle group during each pull-up variation. No significant differences existed within the latissimus dorsi, biceps brachii or posterior deltoid between any of the exercises. For the middle trapezius, towel pull-ups provided significantly lower muscle activity than the traditional pull-up, while no differences between suspension pull-ups and the other variations occurred. In conclusion, only one muscular difference existed between the exercise variations and all versions examined provided electromyographical values, determined by current literature, to invoke a sufficient stimulus to promote increases in muscle strength and hypertrophy. Although further research is needed, practitioners can be confident when programming any of the movement variations examined when attempting to elicit adaptations of muscular strength and hypertrophy.

  14. Push for the Second Screen

    DEFF Research Database (Denmark)

    Sørensen, Jannick Kirk; Sørensen, Lene Tolstrup

    Users’ perception of the relation between the TV screen and a secondary screen (e.g. smartphone or tablet) is examined empirically in a pilot project through a low-fi prototype and interviews. Early observations indicate that the user value/acceptance of push-messages delivered to the second screen...

  15. Getting rid of paper pushing.

    Science.gov (United States)

    Wyatt, C

    1994-04-01

    A hospital in Tacoma, Wash., is taking several steps toward streamlining its business office functions. For example, the hospital is transmitting 90% of its claims electronically and has automated the posting of remittance advice and the billing of Medicare secondary payers. "Eventually we'll have a paperless system; we won't push paper back and forth," the hospital's patient accounts manager says.

  16. Push for the Second Screen

    DEFF Research Database (Denmark)

    Sørensen, Jannick Kirk; Sørensen, Lene Tolstrup

    Users’ perception of the relation between the TV screen and a secondary screen (e.g. smartphone or tablet) is examined empirically in a pilot project through a low-fi prototype and interviews. Early observations indicate that the user value/acceptance of push-messages delivered to the second screen...

  17. Illuminated push-button switch

    Science.gov (United States)

    Iwagiri, T.

    1983-01-01

    An illuminated push-button switch is described. It is characterized by the fact that is consists of a switch group, an operator button opening and closing the switch group, and a light-emitting element which illuminates the face of the operator button.

  18. SNAP: SNowbAll multi-tree Pushing for Peer-to-Peer Media Streaming

    CERN Document Server

    Luo, Jun

    2010-01-01

    Given the respective advantages of the two complimentary techniques for peer-to-peer media streaming (namely tree-based push and mesh-based pull), there is a strong trend of combining them into a hybrid streaming system. Backed by recently proposed mechanisms to identify stable peers, such a hybrid system usually consists of backbone trees formed by the stable peers and other overlay structures in the second tier to accommodate the remaining peers. In this paper, we embrace the hybrid push-pull structure for peer-to-peer media streaming. Our protocol is dominated by a multi-tree push mechanism to minimize the delay in the backbone and is complemented by other overlay structures to cope with peer dynamics. What mainly distinguishes our multi-tree pushing from the conventional ones is an unbalanced tree design guided by the so called snow-ball streaming, which has a provable minimum delay and can be smoothly "melded" with virtually any other existing overlay structures lying in the second tier. We design algori...

  19. 'Supply Push’ or ‘Demand Pull?’: Strategic Recommendations for the Responsible Development of Biofuel in China

    DEFF Research Database (Denmark)

    Ren, Jingzheng; Goodsite, Michael; Sovacool, Benjamin

    2015-01-01

    This study investigates China's biofuel industry—the third largest in the world—by combining a strength, weakness, opportunity and threats (SWOT) analysis with a method known as fuzzy analytic hierarchy process (FAHP). More specifically, the study employs SWOT analysis to identify the influential...... perform, adhering to a "supply push" mentality. Others focus on improving affordability and consumer awareness, adhering to a "demand pull" mentality....

  20. Exploration of PNF pull technology application in the opera legs flexible training feasibility%探索PNF牵拉技术应用于戏曲腿功柔韧素质训练的可行性

    Institute of Scientific and Technical Information of China (English)

    张秋海; 全明辉

    2012-01-01

      目的:探讨PNF牵拉技术应用于戏曲专业学生腿功柔韧性训练的可行性。方法:选取20名2010级戏曲专业武功班的男生,利用PNF牵拉技术进行柔韧性训练。结果:20名受试的学生,左腿的竖叉、横叉,右腿的竖叉、横叉在训练后都比训练前有了显著的提高,且较之前的训练方法,肌肉疼痛感有明显减轻。结论:PNF牵拉技术可以作为一种很好的训练手段,应用于戏曲专业腿功的柔韧素质训练。%  Objective:To study PNF traction technology applied to drama students flexibility training of leg power feasibility.Methods:a total of 20 grade 2010 drama professional martial arts class of boys, using PNF traction technology for flexible training.Results:20 subjects students, left leg vertical fork, cross fork, the right leg vertical fork, cross fork after the training than before training has been significantly improved, and compared to the previous methods of training, muscle pain have significantly reduced.Conclusion: PNF traction technology can be used as a good training method, applied to the professional opera legs flexible diathesis training.

  1. Design of Distributed Prefetching Protocol in Push-to-Peer Video-on-Demand System

    Directory of Open Access Journals (Sweden)

    Thiruselvan. R

    2013-06-01

    Full Text Available Peer-to-peer networks have to streaming the video on the Internet. In P2P streaming system, the upstream bandwidth of peers are larger than video playback rate. This system does not overcome the upstream bandwidth limitation by server based stream delivery. But, the push-to-peer system does not rely on content servers except in the push phase. So, this system can overcome the bandwidth limitation. In this paper is content placement and associated pull policies that allow the optimal use of uplink bandwidth in push-to-peer video-on-demand system. The initial content placement increases the content availability and improves the use of peer uplink bandwidth. The mostly required videos are proactively pushed to the set-top-boxes in the digital subscriber line networks during time of low network utilization that is in the early morning. There are two approaches used for content placement and pull policies, which are Full striping scheme and Code-based placement scheme. The client can easily download and play out video from set-top-boxes. So, it would reduce server load, network load and downloading time. In Full striping scheme, videos are strip into video blocks and push the distinct video block into the set-top-box. This system has to provide high quality of video streaming and to reduce the client’s waiting time. This system can reduce the server load, network load and congestion. In Code-based placement scheme, videos are encoded into coded symbol by using rate less code algorithm. This approach could eliminate the box failure in full striping scheme. When the client’s required data is not available in the set-top-box, then the distributed prefetching protocol used to directly connect client to the video server and streaming the video from video server to client.

  2. CSS3 pushing the limits

    CERN Document Server

    Greig, Stephen

    2013-01-01

    Push CSS3 and your design skills to the limit-and beyond! Representing an evolutionary leap forward for CSS, CSS3 is chock-full of new capabilities that dramatically expand the boundaries of what a styling language can do. But many of those new features remain undocumented, making it difficult to learn what they are and how to use them to create the sophisticated sites and web apps clients demand and users have grown to expect. Until now. This book introduces you to all of CSS3's new and advanced features, and, with the help of dozens of real-world examples and live

  3. Optimizing psychological interventions for trichotillomania (hair-pulling disorder: an update on current empirical status

    Directory of Open Access Journals (Sweden)

    Snorrason I

    2015-04-01

    Full Text Available Ivar Snorrason, Gregory S Berlin, Han-Joo Lee Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA Abstract: Trichotillomania (hair-pulling disorder is a psychiatric condition characterized by a persistent habit of pulling out one's hair. In treatment-seeking populations, hair-pulling disorder can be severe, chronic, and difficult to treat. In the early 1970s, behavioral interventions (eg, habit reversal training were developed and proved effective in treating chronic hair-pulling for many individuals. In order to further increase treatment efficacy and improve long-term outcome, several authors have developed augmented treatment protocols that combine traditional behavioral strategies with other cognitive-behavioral interventions, including cognitive therapy, dialectical behavioral therapy, and acceptance and commitment therapy. In the present review, we give an overview of the clinical and diagnostic features of hair-pulling disorder, describe different cognitive-behavioral interventions, and evaluate research on their efficacy. Keywords: trichotillomania, hair-pulling, cognitive-behavioral therapy, diagnosis, review

  4. Maximization of Growth Rates During Czochralski Pulling

    Science.gov (United States)

    Wargo, M. J.

    1984-01-01

    It was suggested from theory(1-4) that silicon can be grown from the melt at rates far exceeding the current state of the art. Previous theoretical and experimental investigations which predict maximum rates of pulling during Czochralski growth are reviewed. Several experimental methods are proposed to modify the temperature distribution in a growing crystal to achieve higher rates of pulling. A physical model of a Czochralski crystal of germanium in contact with its melt was used to quantitatively determine, by direct measurement of the axial temperature distribution in the solid, the increase in axial temperature gradients effected by an inverted conical heat reflector located above the melt and coaxially about the physical model. Preliminary results indicate that this is an effective method of increasing the thermal resistance between the hot melt and crucible wall and a growing crystal. Under these conditions the enhancement of the interfacial temperature gradients permit a commensurate increase in the rate of crystal pulling.

  5. Android programming pushing the limits

    CERN Document Server

    Hellman, Erik

    2013-01-01

    Unleash the power of the Android OS and build the kinds of brilliant, innovative apps users love to use If you already know your way around the Android OS and can build a simple Android app in under an hour, this book is for you. If you're itching to see just how far you can push it and discover what Android is really capable of, it's for you. And if you're ready to learn how to build advanced, intuitive, innovative apps that are a blast to use, this book is definitely for you. From custom views and advanced multi-touch gestures, to integrating online web services and exploiting the latest

  6. Low Phase Noise SiGe Push-Push Oscillators for Millimeter Wave Frequencies

    OpenAIRE

    2008-01-01

    In this thesis low phase noise SiGe HBT monolithically integrated push-push oscillators for millimeter wave frequency generation are investigated. Nonlinear simulation methods for oscillator signal and noise analysis and device physics at high currents and high voltages are discussed. Push-push oscillators with output frequencies from 63 GHz up to 280 GHz were designed and after fabrication in an external foundry investigated experimentally. For automotive radar applications a VCO with a cent...

  7. Retrospective examination of injuries and physical fitness during Federal Bureau of Investigation new agent training

    Directory of Open Access Journals (Sweden)

    Hauret Keith

    2011-10-01

    Full Text Available Abstract Background A retrospective examination was conducted of injuries, physical fitness, and their association among Federal Bureau of Investigation (FBI new agent trainees. Methods Injuries and activities associated with injuries were obtained from a review of medical records in the medical clinic that served the new agents. A physical fitness test (PFT was administered at Weeks 1, 7 and 14 of the 17-week new agent training course. The PFT consisted of push-ups, sit-ups, pull-ups, a 300-meter sprint, and a 1.5-mile run. Injury data were available from 2000 to 2008 and fitness data were available from 2004 to early 2009. Results During the survey period, 37% of men and 44% of women experienced one or more injuries during the new agent training course (risk ratio (women/men = 1.18, 95% confidence interval = 1.07-1.31. The most common injury diagnoses were musculoskeletal pain (not otherwise specified (27%, strains (11%, sprains (10%, contusions (9%, and abrasions/lacerations (9%. Activities associated with injury included defensive tactics training (48%, physical fitness training (26%, physical fitness testing (6%, and firearms training (6%. Over a 6-year period, there was little difference in performance of push-ups, sit-ups, pull-ups, or the 300-meter sprint; 1.5-mile run performance was higher in recent years. Among both men and women, higher injury incidence was associated with lower performance on any of the physical fitness measures. Conclusion This investigation documented injury diagnoses, activities associated with injury, and changes in physical fitness, and demonstrated that higher levels of physical fitness were associated with lower injury risk.

  8. Retrospective examination of injuries and physical fitness during Federal Bureau of Investigation new agent training.

    Science.gov (United States)

    Knapik, Joseph J; Spiess, Anita; Swedler, David; Grier, Tyson; Hauret, Keith; Yoder, James; Jones, Bruce H

    2011-10-09

    A retrospective examination was conducted of injuries, physical fitness, and their association among Federal Bureau of Investigation (FBI) new agent trainees. Injuries and activities associated with injuries were obtained from a review of medical records in the medical clinic that served the new agents. A physical fitness test (PFT) was administered at Weeks 1, 7 and 14 of the 17-week new agent training course. The PFT consisted of push-ups, sit-ups, pull-ups, a 300-meter sprint, and a 1.5-mile run. Injury data were available from 2000 to 2008 and fitness data were available from 2004 to early 2009. During the survey period, 37% of men and 44% of women experienced one or more injuries during the new agent training course (risk ratio (women/men) = 1.18, 95% confidence interval = 1.07-1.31). The most common injury diagnoses were musculoskeletal pain (not otherwise specified) (27%), strains (11%), sprains (10%), contusions (9%), and abrasions/lacerations (9%). Activities associated with injury included defensive tactics training (48%), physical fitness training (26%), physical fitness testing (6%), and firearms training (6%). Over a 6-year period, there was little difference in performance of push-ups, sit-ups, pull-ups, or the 300-meter sprint; 1.5-mile run performance was higher in recent years. Among both men and women, higher injury incidence was associated with lower performance on any of the physical fitness measures. This investigation documented injury diagnoses, activities associated with injury, and changes in physical fitness, and demonstrated that higher levels of physical fitness were associated with lower injury risk.

  9. Push: A Technology with Staying Power?

    Science.gov (United States)

    Bing, Michelle

    1997-01-01

    Describes push technology, which supplies automatic newsfeeds to users from a select group of Internet and intranet news, information, and software resources. Highlights include similarities to selective dissemination of information, intranet management, and addresses of some push technology sites on the World Wide Web. (LRW)

  10. UK pulls out of plans for ILC

    CERN Multimedia

    Durrani, Matin

    2007-01-01

    "A funding crisis at one of the UK's leading research councils has forced the country to pull out of plans for the International Linear Collider (ILC). The science and Technology Facilities Council (STFC) says in a report published today that it does not see "a practicable path towards the realization of this facility as currently conceived on a reasonable timescale". (1 page)

  11. Intermode beat stabilized laser with frequency pulling.

    Science.gov (United States)

    Yokoyama, S; Araki, T; Suzuki, N

    1994-01-20

    A frequency-stabilized two-mode He-Ne laser has been developed. The intermode beat frequency of the experimental laser was approximately 600 MHz for a 25-cm cavity. The laser frequency in which the mode stands is pulled to the center of the gain curve (frequency pulling). The degree of pulling depends on where the longitudinal modes stand in the broadened gain curve. Beat frequency is thereby changed periodically of the order of hundreds of kilohertz with respect to cavity expansion. The frequency pulling was effectively used for frequency stabilization of the laser. The standing position of the longitudinal mode lights was locked in the gain curve by controlling the change of intermode beat frequency. A microwave mixer was applied to extract the frequency change of the intermode beat. Excellent frequency stability (10(10) for the laser oscillation and 10(6) for the beat frequency) was attained. The polarization orthogonality of the proposed laser was superior to that of Zeeman lasers.

  12. An ergonomic evaluation of handle height and load in maximal and submaximal cart pushing.

    Science.gov (United States)

    Resnick, M L; Chaffin, D B

    1995-06-01

    Awareness of the hazards of repetitive lifting has brought about significant changes in the design of industrial jobs. Pushing and pulling tasks have become increasingly common as the result of the introduction of a variety of carts and other materials-handling assistance devices. In order to predict the peak performance of workers in these tasks, and the biomechanical stresses that can result from them, the exertions involved in cart pushing were studied. Four subjects of various strengths pushed carts with loads from 45 to 450 kg at several heights. Peak push forces reached 500 N for male subjects and 200 N for female subjects. Strong subjects moved a 45 kg cart at velocities of 1.1 m s(-1) and a 450 kg cart at velocities of 0.8 m s(-1). Weaker subjects moved the carts at velocities of 0.5 and 0.4 m s(-1) respectively. Calculated static compression forces at the L5/S1 spinal disc were consistently above the NIOSH Action Limit of 3400 N for strong subjects when the cart load reached 225 kg.

  13. Affective and sensory correlates of hair pulling in pediatric trichotillomania.

    Science.gov (United States)

    Meunier, Suzanne A; Tolin, David F; Franklin, Martin

    2009-05-01

    Hair pulling in pediatric populations has not received adequate empirical study. Investigations of the affective and sensory states contributing to the etiology and maintenance of hair pulling may help to elucidate the classification of trichotillomania (TTM) as an impulse control disorder or obsessive-compulsive spectrum disorder. The current study aimed to examine children's self-reported affective and sensory states associated with hair pulling. Fifteen participants completed a questionnaire assessing children's experiences during first and recent hair pulling episodes. Results revealed that pulling hair for the first time was associated with pleasure and pain whereas recent hair pulling was associated with pleasure only, suggesting that the punishing quality of hair pulling may diminish over time. The findings also support the notion that hair pulling may be maintained primarily through positive reinforcement, which is consistent with its classification as an impulse control disorder.

  14. Miniature Tractor Pull Helps Teach Mechanical Power Transmission.

    Science.gov (United States)

    Waggoner, Todd C.

    1996-01-01

    A miniature tractor pull was developed as a high school activity, enabling students to assess a tractor's pulling capabilities and determine subsequent horsepower. The activity takes the textbook concept of horsepower and makes it come alive. (JOW)

  15. Customized Pull Systems for Single-Product Flow Lines

    NARCIS (Netherlands)

    Gaury, E.G.A.; Kleijnen, J.P.C.; Pierreval, H.

    1998-01-01

    Traditionally pull production systems are managed through classic control systems such as Kanban, Conwip, or Base stock, but this paper proposes ‘customized’ pull control. Customization means that a given production line is managed through a pull control system that in principle connects each stage

  16. 30 CFR 75.828 - Trailing cable pulling.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Trailing cable pulling. 75.828 Section 75.828... Longwalls § 75.828 Trailing cable pulling. The trailing cable must be de-energized prior to being pulled by any equipment other than the continuous mining machine. The cable manufacturer's recommended...

  17. Customized Pull Systems for Single-Product Flow Lines

    NARCIS (Netherlands)

    Gaury, E.G.A.; Kleijnen, J.P.C.; Pierreval, H.

    1998-01-01

    Traditionally pull production systems are managed through classic control systems such as Kanban, Conwip, or Base stock, but this paper proposes ‘customized’ pull control. Customization means that a given production line is managed through a pull control system that in principle connects each stage

  18. Pushing Boundaries while Maintaining Stability

    DEFF Research Database (Denmark)

    Lippke, Lena; Wegener, Charlotte

    The aim of this paper is to frame two major imperatives within vocational education; retention and innovation. During recent years, teachers within the context of the Vocational Educational Training system in Denmark have had to face two co-existing political demands in their everyday teaching...

  19. Pushing Boundaries while Maintaining Stability

    DEFF Research Database (Denmark)

    Lippke, Lena; Wegener, Charlotte

    The aim of this paper is to frame two major imperatives within vocational education; retention and innovation. During recent years, teachers within the context of the Vocational Educational Training system in Denmark have had to face two co-existing political demands in their everyday teaching pr...

  20. Surface plasmon polariton assisted optical pulling force

    CERN Document Server

    Petrov, M I; Bogdanov, A A; Shalin, A S; Dogariu, A

    2016-01-01

    We demonstrate both analytically and numerically the existence of optical pulling forces acting on particles located near plasmonic interfaces. Two main factors contribute to the appearance of this negative reaction force. The interference between the incident and reflected waves induces a rotating dipole with an asymmetric scattering pattern while the directional excitation of surface plasmon polaritons (SPP) enhances the linear momentum of scattered light. The strongly asymmetric SPP excitation is determined by spin-orbit coupling of the rotating dipole and surface plasmon polariton. As a result of the total momentum conservation, the force acting on the particle points in a direction opposite to the incident wave propagation. We derive analytical expressions for the force acting on a dipolar particles placed in the proximity of plasmonic surfaces. Analytical expressions for this pulling force are derived within the dipole approximation and are in excellent agreement with results of electromagnetic numerica...

  1. Training Approach-Avoidance of Smiling Faces Affects Emotional Vulnerability in Socially Anxious Individuals

    Directory of Open Access Journals (Sweden)

    Mike eRinck

    2013-08-01

    Full Text Available Previous research revealed an automatic behavioral bias in high socially anxious individuals (HSAs: Although their explicit evaluations of smiling faces are positive, they show automatic avoidance of these faces. This is reflected by faster pushing than pulling of smiling faces in an Approach-Avoidance Task (AAT; Heuer, Rinck, & Becker, 2007. The current study addressed the causal role of this avoidance bias for social anxiety. To this end, we used the AAT to train HSAs, either to approach smiling faces or to avoid them. We examined whether such an AAT training could change HSAs’ automatic avoidance tendencies, and if yes, whether AAT effects would generalize to a new approach task with new facial stimuli, and to mood and anxiety in a social threat situation (a video-recorded self-presentation. We found that HSAs trained to approach smiling faces did indeed approach female faces faster after the training than HSAs trained to avoid smiling faces. Moreover, approach-faces training reduced emotional vulnerability: It led to more positive mood and lower anxiety after the self-presentation than avoid-faces training. These results suggest that automatic approach-avoidance tendencies have a causal role in social anxiety, and that they can be modified by a simple computerized training. This may open new avenues in the therapy of social phobia.

  2. RF Bead Pull Measurements of the DQW

    CERN Document Server

    Jaume, Guillaume

    2015-01-01

    This report was written within the framework of the CERN Summer Student Program. It is focused on the Radio Frequency study of the Double Quarter Wave Crab Cavity [1] considered for the crab-crossing scheme of the LHC Luminosity upgrade [2]. HFSS simulation [3] and Bead-Pull Measurements technique were used for the characterization of the higher-order terms of the main deflecting mode.

  3. Laparoscopic assisted anorectal pull through: Reformed techniques

    OpenAIRE

    2009-01-01

    Aim: To assess the modifications in the technique of laparoscopic assisted anorectal pull through (LAARP) practiced at our institute and analyze the post operative outcome and associated complications. Materials and Methods: A retrospective study from January 2001 to May 2009 analyzing LAARP for high anorectal malformations. Results: A total of 40 patients - 34 males and six females, in the age group of two months to six years were studied. Staged procedure was done in 39 patients; one c...

  4. Exercise-training intervention studies in competitive swimming.

    Science.gov (United States)

    Aspenes, Stian Thoresen; Karlsen, Trine

    2012-06-01

    Competitive swimming has a long history and is currently one of the largest Olympic sports, with 16 pool events. Several aspects separate swimming from most other sports such as (i) the prone position; (ii) simultaneous use of arms and legs for propulsion; (iii) water immersion (i.e. hydrostatic pressure on thorax and controlled respiration); (iv) propulsive forces that are applied against a fluctuant element; and (v) minimal influence of equipment on performance. Competitive swimmers are suggested to have specific anthropometrical features compared with other athletes, but are nevertheless dependent on physiological adaptations to enhance their performance. Swimmers thus engage in large volumes of training in the pool and on dry land. Strength training of various forms is widely used, and the energetic systems are addressed by aerobic and anaerobic swimming training. The aim of the current review was to report results from controlled exercise training trials within competitive swimming. From a structured literature search we found 17 controlled intervention studies that covered strength or resistance training, assisted sprint swimming, arms-only training, leg-kick training, respiratory muscle training, training the energy delivery systems and combined interventions across the aforementioned categories. Nine of the included studies were randomized controlled trials. Among the included studies we found indications that heavy strength training on dry land (one to five repetitions maximum with pull-downs for three sets with maximal effort in the concentric phase) or sprint swimming with resistance towards propulsion (maximal pushing with the arms against fixed points or pulling a perforated bowl) may be efficient for enhanced performance, and may also possibly have positive effects on stroke mechanics. The largest effect size (ES) on swimming performance was found in 50 m freestyle after a dry-land strength training regimen of maximum six repetitions across three

  5. Inching toward 'push-button' meshing

    National Research Council Canada - National Science Library

    James Masters

    2015-01-01

      While "push-button" meshing remains an elusive goal, advances in 2015 have brought the technology to the point where meshes can be constructed with relative ease when appropriate surfaces are available...

  6. Pulling rigid bodies through granular material

    Science.gov (United States)

    Kubik, Ryan; Dressaire, Emilie

    2016-11-01

    The need for anchoring systems in granular materials such as sand is present in the marine transportation industry, e.g. to layout moorings, keep vessels and docks fixed in bodies of water, build oil rigs, etc. The holding power of an anchor is associated with the force exerted by the granular media. Empirical evidence indicates that the holding power depends on the size and shape of the anchoring structure. In this model study, we use a two-dimensional geometry in which a rigid body is pulled through a granular media at constant velocity to determine the drag and lift forces exerted by a granular medium on a moving object. The method allows measuring the drag force and recording the trajectory of the rigid object through the sand. We systematically vary the size and geometry of the rigid body, the properties of the granular medium and the extraction speed. For different initial positions of a cylindrical object pulled horizontally through the medium, we record large variations in magnitude of the drag and a significant lift force that pulls the object out of the sand.

  7. A focus group study of predictors of relapse in electronic gaming machine problem gambling, part 2: factors that 'pull' the gambler away from relapse.

    Science.gov (United States)

    Oakes, J; Pols, R; Battersby, M; Lawn, S; Pulvirenti, M; Smith, D

    2012-09-01

    This study aimed to develop an empirically based description of relapse in Electronic Gaming Machine (EGM) problem gambling (PG) by describing the processes and factors that 'pull' the problem gambler away from relapse contrasted with the 'push' towards relapse. These conceptualisations describe two opposing, interacting emotional processes occurring within the problem gambler during any relapse episode. Each relapse episode comprises a complex set of psychological and social behaviours where many factors interact sequentially and simultaneously within the problem gambler to produce a series of mental and behaviour events that end (1) with relapse where 'push' overcomes 'pull' or (2) continued abstinence where 'pull' overcomes 'push'. Four focus groups comprising thirty participants who were EGM problem gamblers, gamblers' significant others, therapists and counsellors described their experiences and understanding of relapse. The groups were recorded, recordings were then transcribed and analysed using thematic textual analysis. It was established that vigilance, motivation to commit to change, positive social support, cognitive strategies such as remembering past gambling harms or distraction techniques to avoid thinking about gambling to enable gamblers to manage the urge to gamble and urge extinction were key factors that protected against relapse. Three complementary theories emerged from the analysis. Firstly, a process of reappraisal of personal gambling behaviour pulls the gambler away from relapse. This results in a commitment to change that develops over time and affects but is independent of each episode of relapse. Secondly, relapse may be halted by interacting factors that 'pull' the problem gambler away from the sequence of mental and behavioural events, which follow the triggering of the urge and cognitions to gamble. Thirdly, urge extinction and apparent 'cure' is possible for EGM gambling. This study provides a qualitative, empirical model for

  8. The pull of inter-provincial migration of rural labor force and its influence on policy-making

    Institute of Scientific and Technical Information of China (English)

    Huo Weidong; Deng Guoying; Wang Peng; Yang Xiaojun

    2006-01-01

    As a social phenomenon closely related to development of economy, the population is always the focus of economists' attention. Based on the fifth census in 2001, this paper analyzes labor migration in Hubei Province and establishes an econometric model to analyze the pull according to the push and pull theory, which is the famous theory on the population flow and migration. It points out that the per capita consumption and the employment rate attract strongly the rural labors and makes a deep exploration into the ensuing problems. Such conclusion is a special reference to the decision-making of government. The government can provide some guidance to the rural labors according to the per capita consumption and the employment rate in order to avoid the futility of blind migration.

  9. A K-Band Push-Push VCO MMIC using embedded frequency doubling mechanism

    OpenAIRE

    Sim, Sang-Hoon; Ko, Sangsoo; Hong, Songcheol

    2004-01-01

    A K-Band Push-Push VCO MMIC which has small size, high output power and low phase noise is presented. This push-push VCO utilize the embedded frequency doubling mechanism of cross coupled topology. A commercial InGaP/GaAs HBT technology with the f T of 60 GHz and the fMAX of 110 GHz was used for the implementation. The oscillation frequency is from 21.02 GHz to 21.17 GHz. The peak output power of the VCO is 1.7dBm. The phase noise is -110dBc/Hz at 1MHz offset from 2...

  10. Impact of Androstenone on Leash Pulling and Jumping Up in Dogs

    Directory of Open Access Journals (Sweden)

    Glenna Pirner

    2016-05-01

    Full Text Available Dogs are relinquished to shelters due to behavioral problems, such as leash pulling and jumping up. Interomones are chemical cues produced by one species that elicit a response in a different species. We reported earlier that androstenone, a swine sex pheromone, acts as an interomone to reduce barking in dogs. Here we report two models using 10 dogs/study: a dog jumping and a dog walking model. For the leash-pulling model, each time the dog pulled on the leash the walker either did nothing (NOT, or sprayed the dog with water (H2O, androstenone + water (ANH, androstenone 0.1 µg/mL (AND1, or androstenone 1.0 µg/mL (AND2. The number of pulls during each walk was counted. For the jumping up model, each time the dog jumped the researcher did nothing (NOT, or sprayed the dog with H2O, ANH, AND1, or AND2. The number of jumps and the time between jumps were recorded. In Study 1, ANH, AND1, and AND2 each reduced leash pulling more than NOT and H2O (p< 0.01. In Study 2, all treatments were effective in reducing jumping up behavior. Androstenone reduced jumping up, but not beyond that elicited by a spray of water alone. We conclude that androstenone in multiple delivery vehicles reduced leash pulling. The burst of air intended as a disruptive stimulus in the correction sprays may be too harsh for more sensitive dogs, and as such use of these sprays is cautioned in these animals. For other dogs, this interomone can be used to stop some behavior immediately or as a part of a training program to reduce undesirable behavior.

  11. Pull-pull position control of dual motor wire rope transmission

    Science.gov (United States)

    Guo, Quan; Jiao, Zongxia; Yan, Liang; Yu, Qian; Shang, Yaoxing

    2016-08-01

    Wire rope transmission is very efficient because of the small total moving object mass. The wire rope could only transmit pulling force. Therefore it has to be kept in a tightened state during transmission; in high speed applications the dynamic performance depends on the rope's stiffness, which can be adjusted by the wire rope tension. To improve the system dynamic performance output, this paper proposes a novel pull-pull method based on dual motors connected by wire ropes, for precise, high speed position control applications. The method can regulate target position and wire rope tension simultaneously. Wire ropes remain in a pre-tightening state at all times, which prevents the influence of elasticity and reduces the position tracking error in the changing direction process. Simulations and experiments were conducted; the results indicate that both position precision and superior dynamic performance can be synchronously achieved. The research is relevant to space craft precision pointing instruments.

  12. Two-Man Bobsled Push Start Analysis

    Directory of Open Access Journals (Sweden)

    Lopes Alexandre Dias

    2016-04-01

    Full Text Available The importance of push start times on bobsled performance was evidenced by some studies, but at this moment there is no article to the authors’ knowledge that describes the bobsled push start. Thus, the objectives of this study were to describe the two-man bobsled push start, analyze the differences between teams, and estimate the most important variable analyzed. We hypothesized that the pilot and brakeman athletes’ movement patterns during a bobsled pushing start can be described. The images used in this study were obtained during the men’s two-man XIV World Championship of Bobsled (2004. Fifteen best teams participating in the championship were recorded, and four start runs for each team were analyzed. The videos were captured by two digital video cameras. The pilot athletes were analyzed during the moment that they touched the lateral push bar of the sled, and the brakemen were analyzed during the first take-off and first landing. The teams were pooled in three groups of five teams using the final ranking of pushing time. We concluded that there was a distinct pattern movement for pilots and brakemen. The initial position of the majority of the pilots was localized slightly behind the bar. After touching the lateral bar, the pilots remained in a semi-squat position, pushing the sled forward in a pattern of marching movement. All brakemen used the board attached to the track as a support for both feet at the start. The brakeman gave the greatest contribution to break the inertia of the sled. There was no significant difference of movement between the three groups analyzed for the pilot and the brakeman.

  13. The Push Is On: What Push Technology Means to the Librarian.

    Science.gov (United States)

    Gustitus, Cheryl

    1998-01-01

    "Push technology," or Webcasting, employs user defined criteria to search for specific information and deliver it when and where directed, enhancing the value special librarians add to the information dissemination process. This article examines push technology, its Internet and Intranet applications, and commercially available…

  14. Effect of push handle height on net moments and forces on the musculoskeletal system during standardized wheelchair pushing tasks

    NARCIS (Netherlands)

    Van Der Woude, L H; Van Koningsbruggen, C M; Kroes, A L; Kingma, I

    1995-01-01

    The aim of this investigation was to analyze the external forces and biomechanical loading on the musculoskeletal system during wheelchair pushing, in relation to different push handle heights. In addition, recommendations for wheelchair pushing in accordance with push handle height are made. Eight

  15. The Uneven Legal Push for Europe

    DEFF Research Database (Denmark)

    Wind, Marlene; Martinsen, Dorte Sindbjerg; Rotger, Gabriel Pons

    2009-01-01

    National courts have been key players in the legal push for Europe, though notably to varying degrees. This paper examines the persisting variations in the referral rates of national courts and the underlying causal factors, aiming to better understand why some member states' courts have been more...... reluctant to join in the legal push for Europe. By using econometric methods, it challenges the modified neofunctionalist argument that the extent of intra-EC trade explains the referral practice of the individual member states. Majoritarian democracy is hypothesized as a causal factor in the low referral...... of majoritarian democracy on the number of referrals. The paper concludes that, owing to the uneven legal push for Europe, some member states and their citizens remain at arms' length from the legal integration process - and, in consequence, from the full impact of European integration....

  16. Laparoscopic assisted anorectal pull through: Reformed techniques

    Directory of Open Access Journals (Sweden)

    Bhandary Karthik

    2009-01-01

    Full Text Available Aim: To assess the modifications in the technique of laparoscopic assisted anorectal pull through (LAARP practiced at our institute and analyze the post operative outcome and associated complications. Materials and Methods: A retrospective study from January 2001 to May 2009 analyzing LAARP for high anorectal malformations. Results: A total of 40 patients - 34 males and six females, in the age group of two months to six years were studied. Staged procedure was done in 39 patients; one child with recto vestibular fistula underwent single stage procedure. All the patients withstood surgery well. One patient required conversion due to problems in gaining enough length for the distal rectum in a patient with rectovesical fistula so colostomy was closed and re-located at a proximal splenic flexure. The complications were mucosal prolapse (six cases, anal stenosis (three, adhesive obstruction (two, distal rectal necrosis (one, and urethral diverticulum (one. The patients were followed up with clinical evaluation and continence scoring. The progress has been satisfactory and weight-gain is adequate. Conclusions: The advantages of the reformed techniques are as follows: Transcutaneous bladder stitch provides excellent visualization; traction over the fistula helps in dissection of the puborectalis, dividing the fistula without ligation is safe, railroading of Hegar′s dilators over the suction canula creates adequate pull through channel, saves time and makes procedure simpler with reproducible comparable reports.

  17. The Uneven Legal Push for Europe

    DEFF Research Database (Denmark)

    Wind, Marlene; Martinsen, Dorte Sindbjerg; Rotger, Gabriel Pons

    2009-01-01

    National courts have been key players in the legal push for Europe, though notably to varying degrees. This paper examines the persisting variations in the referral rates of national courts and the underlying causal factors, aiming to better understand why some member states' courts have been more...... reluctant to join in the legal push for Europe. By using econometric methods, it challenges the modified neofunctionalist argument that the extent of intra-EC trade explains the referral practice of the individual member states. Majoritarian democracy is hypothesized as a causal factor in the low referral...

  18. Perspectives of oil pulling therapy in dental practice

    Directory of Open Access Journals (Sweden)

    T Lakshmi

    2013-01-01

    Full Text Available Oil pulling has its origin in Ayurvedic medicine, is a natural remedy to improve oral health. Its antibacterial properties help to eradicate the bacteria and other debris from adhering to the oral cavity. It reduces the accumulation of plaque, prevents halitosis, cavities, gingivitis. It is used to heal the bleeding gums and mouth ulcers. Oil pulling with sesame oil improves overall health. Other than oral health, oil pulling also helps in reducing asthma, allergies, chronic fatigue, diabetes, migraine headaches and chronic skin problems. It works by detoxifying or cleansing the body. The aim of this article is to highlight the benefits of oil pulling in management of oral health.

  19. Reversing the brain drain from Eastern European countries: the push' and pull' factors

    Energy Technology Data Exchange (ETDEWEB)

    Vizi, E.S. (Postgraduate Medical School, Budapest (Hungary) Hungarian Academy of Sciences, Budapest (Hungary) Yeshiva Univ., New York, NY (United States))

    1993-01-01

    A mass departure of intellectuals is going on in countries such as Poland, Russia, the Ukraine, Czechoslovakia, Hungary, Bulgaria, and Romania. There is growing concern about the increasing number of intellectuals who have left, or are going to leave, these countries. The main problem is not that scientists and intellectuals are leaving to go abroad to work under better conditions - that is certainly beneficial for science as a whole. Rather, the problem occurs when they do not return. The migration of professionals, even if it is only temporary, only reflects the operation of an international market for specialized human capital. However, a minimum level of human capital is indispensable to a country's economic development. A loss of skilled human resources will ultimately have a grave impact on the economy and jeopardize development programs. There are several reasons for this migration. Top-level scientists have always been drawn to countries that offer greater attractions - facilities, salaries, career prospects, satisfaction, prestige. Drastic changes are needed in the official policy toward R D in Eastern European Countries. The atmosphere must be changed to make it more favorable for intellectual work. In addition, international agencies and governments of developed countries should help these poorer countries to reverse the brain drain. A program of Science and Technology for stability should be created in order to provide direct assistance to basic and applied scientific and technical research in these countries. 16 refs., 3 tabs.

  20. Push or Pull? -- Cryo-Electron Microscopy of Microtubule's Dynamic Instability and Its Roles in the Kinetochore

    Science.gov (United States)

    Wang, Hong-Wei

    2009-03-01

    Microtubule is a biopolymer made up of alpha-beta-tubulin heterodimers. The tubulin dimers assemble head-to-tail as protofilaments and about 13 protofilaments interact laterally to form a hollow cylindrical structure which is the microtubule. As the major cytoskeleton in all eukaryotic cells, microtubules have the intrinsic property to switch stochastically between growth and shrinkage phases, a phenomenon termed as their dynamic instability. Microtubule's dynamic instability is closely related to the types of nucleotide (GTP or GDP) that binds to the beta-tubulin. We have biochemically trapped two types of assembly states of tubulin with GTP or GDP bound representing the polymerizing and depolymerizing ends of microtubules respectively. Using cryo-electron microscopy, we have elucidated the structures of these intermediate assemblies, showing that tubulin protofilaments demonstrate various curvatures and form different types of lateral interactions depending on the nucleotide states of tubulin and the temperature. Our work indicates that during the microtubule's dynamic cycle, tubulin undergoes various assembly states. These states, different from the straight microtubule, lend the highly dynamic and complicated behavior of microtubules. Our study of microtubule's interaction with certain kinetochore complexes suggests that the intermediate assemblies are responsible for specific mechanical forces that are required during the mitosis or meiosis. Our discoveries strongly suggest that a microtubule is a molecular machine rather than a simple cellular scaffold.