Academic literature on the topic 'Videography. eng'
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Journal articles on the topic "Videography. eng"
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Bortier, Hilde, and L. C. A. Vakaet. "Fate mapping the neural plate and the intraembryonic mesoblast in the upper layer of the chicken blastoderm with xenografting and time-lapse videography." Development 116, Supplement (April 1, 1992): 93–97. http://dx.doi.org/10.1242/dev.116.supplement.93.
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The disposition of the Anlage fields of the neural plate and the intraembryonic mesoblast in the upper layer of the chicken blastoderm was studied at the primitive streak stage prior to the regression of Hensen's node (stages 5V to 6V, L. Vakaet (1970) Arch. Biol. 81, 387–426). Chicken blastoderms were cultured by New's technique on a mixture of thin egg white and agar. The anterior half of the deep layer was reflected with a tungsten needle. A circular fragment of the upper layer was punched out with a pulled out Pasteur pipette and discarded. It was replaced with an isotopic and isopolar piece of quail upper layer that was punched out with the same pipette. The deep layer was replaced and the chimeras were reincubated for 24 hours. The xenografts were followed with time-lapse videography. After fixation, the quail cells were located using Le Douarin's quail nucleolar marker technique. Integrating the observations with time-lapse videography and the results of Feulgen stained sections, we have drawn a new fate map of the disposition of the Anlage fields in the upper layer of the chicken blastoderm at stages prior to the regression of Hensen's node (stages 5V to 6V). The disposition of the neural plate and of the notochord, somites, nephrotome and lateral plates was therefore determined before the Anlage fields are morphologically discernible. The pathway of the fields in the upper layer towards their disposition was documented with time-lapse videography in chimeric chicken blastoderms that developed normally.
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Spanjaard, Daniela, Louise Young, and Lynne Freeman. "Emotions in supermarket brand choice." Qualitative Market Research: An International Journal 17, no. 3 (June 3, 2014): 209–24. http://dx.doi.org/10.1108/qmr-10-2012-0049.
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Purpose – The purpose of this article is to show how the application of multiple qualitative methods reveals insights into grocery shopping that cannot be captured via traditional survey methods. Design/methodology/approach – A mixed-method approach was applied where the results of one technique provided the guidelines for the next as a way to understand how decisions are made within a grocery store. A mail survey started the process which subsequently presented input for the focus group, leading to videographic observations, depth interviews and consumer diaries. Findings – The results show that many decisions in the grocery store are not driven by the store environment but rather by emotional connections to the brand. This suggests that using behavioral and attitudinal surveys to understand this perspective may not adequately capture important aspects of grocery buying. Instead, consideration must be given to alternative methods which offer the shopper freedom to discuss what is important to them in terms of product selection. Research limitations/implications – This study is unique in applying multiple qualitative methods to an environment that is often overlooked as a source for meaningful insights into consumer decisions. The ability to use methods such as videography and self-assessment provides consequential reasons behind consumer behaviour rather than just statistical measurements of this. Practical implications – The results make a note of caution for retailers. Radical changes to brand offerings (e.g. deleting lines) and accessibility to preferred products (e.g. out of stocks, store layouts) runs the risk of potentially isolating regular customers. Our research shows that when a favorite product is not available, a substitute is not likely. Instead respondents tend to go to another store that does stock their brand, or they buy a smaller, cheaper product to “make do” until the next shop. Neither option is a good outcome for the consumer, the manufacturer or the store. Originality/value – This study will show that for grocery buying, not all decisions are rational where the use of available information is what drives the final brand choice. Instead, consumers display evidence of emotion that one research method in isolation is unlikely to adequately capture.
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Gregory, Katherine. "The Video Camera Spoiled My Ethnography: A Critical Approach." International Journal of Qualitative Methods 19 (January 1, 2020): 160940692096376. http://dx.doi.org/10.1177/1609406920963761.
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As videography and other media technologies are normalized in the field of qualitative methods for the purpose of data collection, there is a growing need to discuss the benefits and limitations of these data collection tools. This article chronicles an ethnographic video study focused on the experiences of Muslim adults living in the Netherlands, and why the author opted to end the project. Issues focus on reckoning with the imperial gaze of the camera, performative behavior of participants before the camera and interdisciplinary tensions the researcher faced from conflicting trainings as a qualitative methodologist and media practitioner.
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Simons, R. S., W. O. Bennett, and E. L. Brainerd. "Mechanics of lung ventilation in a post-metamorphic salamander, Ambystoma Tigrinum." Journal of Experimental Biology 203, no. 6 (March 15, 2000): 1081–92. http://dx.doi.org/10.1242/jeb.203.6.1081.
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The mechanics of lung ventilation in frogs and aquatic salamanders has been well characterized, whereas lung ventilation in terrestrial-phase (post-metamorphic) salamanders has received little attention. We used electromyography (EMG), X-ray videography, standard videography and buccal and body cavity pressure measurements to characterize the ventilation mechanics of adult (post-metamorphic) tiger salamanders (Ambystoma tigrinum). Three results emerged: (i) under terrestrial conditions or when floating at the surface of the water, adult A. tigrinum breathed through their nares using a two-stroke buccal pump; (ii) in addition to this narial two-stroke pump, adult tiger salamanders also gulped air in through their mouths using a modified two-stroke buccal pump when in an aquatic environment; and (iii) exhalation in adult tiger salamanders is active during aquatic gulping breaths, whereas exhalation appears to be passive during terrestrial breathing at rest. Active exhalation in aquatic breaths is indicated by an increase in body cavity pressure during exhalation and associated EMG activity in the lateral hypaxial musculature, particularly the M. transversus abdominis. In terrestrial breathing, no EMG activity in the lateral hypaxial muscles is generally present, and body cavity pressure decreases during exhalation. In aquatic breaths, tidal volume is larger than in terrestrial breaths, and breathing frequency is much lower (approximately 1 breath 10 min(−)(1)versus 4–6 breaths min(−)(1)). The use of hypaxial muscles to power active exhalation in the aquatic environment may result from the need for more complete exhalation and larger tidal volumes when breathing infrequently. This hypothesis is supported by previous findings that terrestrial frogs ventilate their lungs with small tidal volumes and exhale passively, whereas aquatic frogs and salamanders use large tidal volumes and and exhale actively.
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Cortes, Nelson, Andrew E. Lincoln, Gregory D. Myer, Lisa Hepburn, Michael Higgins, Margot Putukian, and Shane V. Caswell. "Video Analysis Verification of Head Impact Events Measured by Wearable Sensors." American Journal of Sports Medicine 45, no. 10 (May 25, 2017): 2379–87. http://dx.doi.org/10.1177/0363546517706703.
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Background: Wearable sensors are increasingly used to quantify the frequency and magnitude of head impact events in multiple sports. There is a paucity of evidence that verifies head impact events recorded by wearable sensors. Purpose: To utilize video analysis to verify head impact events recorded by wearable sensors and describe the respective frequency and magnitude. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Thirty male (mean age, 16.6 ± 1.2 years; mean height, 1.77 ± 0.06 m; mean weight, 73.4 ± 12.2 kg) and 35 female (mean age, 16.2 ± 1.3 years; mean height, 1.66 ± 0.05 m; mean weight, 61.2 ± 6.4 kg) players volunteered to participate in this study during the 2014 and 2015 lacrosse seasons. Participants were instrumented with GForceTracker (GFT; boys) and X-Patch sensors (girls). Simultaneous game video was recorded by a trained videographer using a single camera located at the highest midfield location. One-third of the field was framed and panned to follow the ball during games. Videographic and accelerometer data were time synchronized. Head impact counts were compared with video recordings and were deemed valid if (1) the linear acceleration was ≥20 g, (2) the player was identified on the field, (3) the player was in camera view, and (4) the head impact mechanism could be clearly identified. Descriptive statistics of peak linear acceleration (PLA) and peak rotational velocity (PRV) for all verified head impacts ≥20 g were calculated. Results: For the boys, a total recorded 1063 impacts (2014: n = 545; 2015: n = 518) were logged by the GFT between game start and end times (mean PLA, 46 ± 31 g; mean PRV, 1093 ± 661 deg/s) during 368 player-games. Of these impacts, 690 were verified via video analysis (65%; mean PLA, 48 ± 34 g; mean PRV, 1242 ± 617 deg/s). The X-Patch sensors, worn by the girls, recorded a total 180 impacts during the course of the games, and 58 (2014: n = 33; 2015: n = 25) were verified via video analysis (32%; mean PLA, 39 ± 21 g; mean PRV, 1664 ± 619 rad/s). Conclusion: The current data indicate that existing wearable sensor technologies may substantially overestimate head impact events. Further, while the wearable sensors always estimated a head impact location, only 48% of the impacts were a result of direct contact to the head as characterized on video. Using wearable sensors and video to verify head impacts may decrease the inclusion of false-positive impacts during game activity in the analysis.
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Zhan, Yakimov, Rühling, Fischbach, Nikolova, Joost, Kaddatz, et al. "High Speed Ventral Plane Videography as a Convenient Tool to Quantify Motor Deficits during Pre-Clinical Experimental Autoimmune Encephalomyelitis." Cells 8, no. 11 (November 14, 2019): 1439. http://dx.doi.org/10.3390/cells8111439.
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Experimental autoimmune encephalomyelitis (EAE) is the most commonly used multiple sclerosis animal model. EAE mice typically develop motor deficits in a caudal-to-rostral pattern when inflammatory lesions have already developed. However, to monitor more subtle behavioral deficits during lesion development (i.e., pre-clinical phase), more sophisticated methods are needed. Here, we investigated whether high speed ventral plane videography can be applied to monitor early motor deficits during ‘pre-clinical’ EAE. For this purpose, EAE was induced in C57BL/6 mice and gait abnormalities were quantified using the DigiGait™ apparatus. Gait deficits were related to histopathological changes. 10 out of 10 control (100%), and 14 out of 18 (77.8%) pre-clinical EAE mice could be evaluated using DigiGait™. EAE severity was not influenced by DigiGait™-related mice handlings. Most gait parameters recorded from day 6 post-immunization until the end of the experiment were found to be stable in control mice. During the pre-clinical phase, when conventional EAE scorings failed to detect any functional impairment, EAE mice showed an increased Swing Time, increased %Swing Stride, decreased %Stance Stride, decreased Stance/Swing, and an increased Absolute Paw Angle. In summary, DigiGait™ is more sensitive than conventional scoring approaches to study motor deficits during the EAE pre-clinical phase.
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Hudson, Cameron M., Marta Vidal-García, Trevor G. Murray, and Richard Shine. "The accelerating anuran: evolution of locomotor performance in cane toads ( Rhinella marina , Bufonidae) at an invasion front." Proceedings of the Royal Society B: Biological Sciences 287, no. 1938 (November 11, 2020): 20201964. http://dx.doi.org/10.1098/rspb.2020.1964.
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As is common in biological invasions, the rate at which cane toads ( Rhinella marina ) have spread across tropical Australia has accelerated through time. Individuals at the invasion front travel further than range-core conspecifics and exhibit distinctive morphologies that may facilitate rapid dispersal. However, the links between these morphological changes and locomotor performance have not been clearly documented. We used raceway trials and high-speed videography to document locomotor traits (e.g. hop distances, heights, velocities, and angles of take-off and landing) of toads from range-core and invasion-front populations. Locomotor performance varied geographically, and this variation in performance was linked to morphological features that have evolved during the toads' Australian invasion. Geographical variation in morphology and locomotor ability was evident not only in wild-caught animals, but also in individuals that had been raised under standardized conditions in captivity. Our data thus support the hypothesis that the cane toad's invasion across Australia has generated rapid evolutionary shifts in dispersal-relevant performance traits, and that these differences in performance are linked to concurrent shifts in morphological traits.
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Liu, Long, Hui-Hui Wang, Sen Qiu, Yun-Cui Zhang, and Zheng-Dong Hao. "Paddle Stroke Analysis for Kayakers Using Wearable Technologies." Sensors 21, no. 3 (January 29, 2021): 914. http://dx.doi.org/10.3390/s21030914.
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Proper stroke posture and rhythm are crucial for kayakers to achieve perfect performance and avoid the occurrence of sport injuries. The traditional video-based analysis method has numerous limitations (e.g., site and occlusion). In this study, we propose a systematic approach for evaluating the training performance of kayakers based on the multiple sensors fusion technology. Kayakers’ motion information is collected by miniature inertial sensor nodes attached on the body. The extend Kalman filter (EKF) method is used for data fusion and updating human posture. After sensor calibration, the kayakers’ actions are reconstructed by rigid-body model. The quantitative kinematic analysis is carried out based on joint angles. Machine learning algorithms are used for differentiating the stroke cycle into different phases, including entry, pull, exit and recovery. The experiment shows that our method can provide comprehensive motion evaluation information under real on-water scenario, and the phase identification of kayaker’s motions is up to 98% validated by videography method. The proposed approach can provide quantitative information for coaches and athletes, which can be used to improve the training effects.
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Pouw, Wim, James P. Trujillo, and James A. Dixon. "The quantification of gesture–speech synchrony: A tutorial and validation of multimodal data acquisition using device-based and video-based motion tracking." Behavior Research Methods 52, no. 2 (October 28, 2019): 723–40. http://dx.doi.org/10.3758/s13428-019-01271-9.
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Abstract There is increasing evidence that hand gestures and speech synchronize their activity on multiple dimensions and timescales. For example, gesture’s kinematic peaks (e.g., maximum speed) are coupled with prosodic markers in speech. Such coupling operates on very short timescales at the level of syllables (200 ms), and therefore requires high-resolution measurement of gesture kinematics and speech acoustics. High-resolution speech analysis is common for gesture studies, given that field’s classic ties with (psycho)linguistics. However, the field has lagged behind in the objective study of gesture kinematics (e.g., as compared to research on instrumental action). Often kinematic peaks in gesture are measured by eye, where a “moment of maximum effort” is determined by several raters. In the present article, we provide a tutorial on more efficient methods to quantify the temporal properties of gesture kinematics, in which we focus on common challenges and possible solutions that come with the complexities of studying multimodal language. We further introduce and compare, using an actual gesture dataset (392 gesture events), the performance of two video-based motion-tracking methods (deep learning vs. pixel change) against a high-performance wired motion-tracking system (Polhemus Liberty). We show that the videography methods perform well in the temporal estimation of kinematic peaks, and thus provide a cheap alternative to expensive motion-tracking systems. We hope that the present article incites gesture researchers to embark on the widespread objective study of gesture kinematics and their relation to speech.
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Brackenbury, John. "Kinematics and hydrodynamics of an invertebrate undulatory swimmer: the damsel-fly larva." Journal of Experimental Biology 205, no. 5 (March 1, 2002): 627–39. http://dx.doi.org/10.1242/jeb.205.5.627.
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SUMMARYThe kinematics and hydrodynamics of free-swimming larvae of Enallagma cyathigerum were investigated using videography combined with a simple wake visualisation technique (tracer dyes). Damsel-fly larvae are undulatory swimmers with two distinct styles of movement: ‘slow’ swimming, in which body undulation is assisted by paddling of the legs, and ‘fast’ swimming, in which the legs are inactive. In both cases, the wake consists of discrete ring vortices shed from the caudal fin at the end of each half-stroke. The vortices propagate away from the mid-line, alternately to one side of the body then the other, at an angle of 67° from dead aft. There is no aft-flowing jet such as that observed in the wakes of continuously swimming fish that use caudal fin propulsion. The estimated momentum within the vortices, and the resultant thrust on the body are in tolerable agreement with calculations based on the large-amplitude bulk momentum model of fish locomotion. However, the drag on the body is not known, so it cannot be concluded with certainty that a force balance exists. The agreement between experiment and prediction gives confidence to the idea that most, if not all, of the vorticity generated by the swimming larva is located within the observable wake elements.
Dissertations / Theses on the topic "Videography. eng"
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Rinaldi, Marcio Antonio. "Ipsis video litteris : processos e procedimentos artísticos da escrita na televisão - videografia /." São Paulo : [s.n.], 2006. http://hdl.handle.net/11449/87020.
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Orientador: Pelópodas Cypriano de OliveiraResumo : O presente trabalho tem como objetivo fazer uma abordagem sobre a escrita na televisão pela Videografia e seus processos e procedimentos artísticos, não se restringindo a forma e tamanho da letra, mas analisando os elementos próprios da linguagem televisiva como espaço, tempo movimento, cor e som. Pesquisei os processos que equivalem a criação e o desenvolvimento da Videografia, as questões técnicas inerentes ao meio televisivo, os procedimentos que permitem maior legibilidade e visualidade,ou seja, que privilegiam a leitura daquilo que está escrito no vídeo, e quais os processos criativos na aplicaçao de um texto no vídeo para que se estabeleça melhor combinação entre a forma e a técnica. Esse trajeto resultou no Trabalho Equivalente, no qual utilizei parte de minha produção como artista visual e profisssional da área de televisão, para compor uma grade de programação de uma emissora fictícia denomonada TV Trabalho Equivalente, apresentado no DVD que acompanha este Relatório Circunstanciado.
Abstract : The present work has as its aim to do an approach about writing on television through Videography and its artistic processes and procedures, not only focusing the shape and size if letters, but also analyzing the specific elements of television aesthetics such as apace, time movement, color and sound. I've research the processes involved on creation and development of Videography, the technical issues inherent to television media, the procedures that bring more legibility and visuality. In other words, procedures which privilege the reading of what is written on TV screen and the creative procedures used to apply a text on screen, in order to establish the best combination between form and technique. This research resulted into the Trabalho Equivalente (Equivalente Work), in which used part of my production as a visual artist and television professional to compose a programming schedule of a fictional television broadcast named TV Trabalho Equivalente, presented on the DVD that goes with this Circumstancial Reporter.
Mestre
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Sayeg, Heitor Siqueira. "Uso de filmagem aérea em perspectiva no apoio à coleta de dados, na pesquisa, no ensino e na divulgação de informações em Geociências /." Rio Claro : [s.n.], 2007. http://hdl.handle.net/11449/102935.
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Orientador: Gilberto José GarciaBanca: Sergio dos Anjos Ferreira Pinto
Banca: Arquimedes Peres Filho
Banca: Norberto Morales
Banca: Olavo Raymundo Junior
Resumo: Fotografia aérea NADIR é um conceito usado rotineiramente por geólogos e pesquisadores de vários campos de atividade. Filmagem aérea de baixa altitude, em perspectiva ou ortogonal, é um recurso muito acessível, pela qualidade e relação custo-benefício dos equipamentos digitais disponíveis, pela capacidade de processamento e facilidade de operação dos softwares e hardwares lançados no mercado e pelo custo da hora de vôo em aviões de pequeno porte. A visualização da organização das paisagens através de filmagens aéreas em perspectiva permite a construção de um banco de dados de fácil manuseio e fornece um ponto de vista complementar às informações derivadas de outras fontes. Os estudos e ações efetuados buscaram explorar essa técnica de registro de dados e testar seu potencial para compor material didático e transmitir informações específicas de interesse geológico.
Abstract: Vertical aerial videography is a commonly technique used by geologists and researchers from several fields of knowledge. Aerial videography of low altitude, in oblique viewing, is a resource not spread, but very accessible, by the quality of digital equipment available, by capacity and facility of software and hardware operation and by the low cost of flight hour in small planes. The terrain observation (imaging) and oblique visualization of landscape in TV language allow building data base, to promote discrimination of surface landforms and morphologic patterns with tectonic meanings, and supply an approach that supplement the information derived from other media. In this work the goal was to apply this technique of data register in low cost and complexity of data treatment, test its aptitude to compose the didactic material and transmit specific information from geological interest.
Doutor
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Pancher, Andréia Medinilha. "Desenvolvimento de métodos para identificação e caracterização de Brownfields têxteis em Americana - SP : potencialidades e limitações da videografia /." Rio Claro : [s.n.], 2006. http://hdl.handle.net/11449/100071.
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Orientador: Maria Isabel Castreghini de FreitasBanca: Luis Enrique Sánchez
Banca: Demóstenes Ferreira da Silva
Banca: Silvia Aparecida Guarnieri Ortigoza
Banca: Magda Adelaide Lombardo
Resumo: Esta tese se fundamenta numa pesquisa cujo objetivo principal foi o desenvolvimento de metodologia de Sensoriamento Remoto para identificar, mapear e caracterizar brownfields têxteis. A abordagem ambientou-se no município de Americana/SP e investigou a presença dos inúmeros brownfields resultantes da crise econômica que, a partir da década de 90, atingiu a cidade que se constituía num dos grandes pólos nacionais da indústria têxtil. Através de técnicas de Cartografia Digital procedeu-se ao mapeamento da indústria têxtil e posterior análise da evolução sócio-espacial dessa atividade. Três setores de cadastro foram selecionados para o detalhamento da pesquisa. Assim, foram elaborados mapas temáticos, correspondentes às quadras que abrangem brownfields têxteis, integrando-se os dados das imagens videográficas às informações do cadastro e das fotografias aéreas de 1978 e 1996. As técnicas de Sensoriamento Remoto, em especial a videografia, demonstraram eficácia na discriminação de alvos urbanos e na caracterização dos imóveis. Devido a alta resolução das imagens, as feições presentes nos lotes foram facilmente discriminadas, com uma média de 92% de acertos entre os três setores, identificando-se 19 brownfields. Complementando a pesquisa, houve a aplicação de questionário junto à população das áreas analisadas, visando perceber a relação dos moradores com os galpões abandonados. Com base nos mapeamentos e resultados dos questionários foram elaboradas propostas de revalorização dos brownfields, compatíveis com a realidade local.
Abstract: This thesis if bases on a research whose basic objective was the development of methodology of Remote Sensoriament to identify, to mapping and to characterize textile brownfields. The boarding was it occurred in the city of Americana/SP and investigated resultant the innumerable presence of brownfields of the economic crisis that, from the decade of 90, it reached the city that if to constitutet one of the great national polar regions of the textile industry. Through techniques of Digital Cartography it was proceeded the mapping from the textile industry and posterior analysis of the social evolution of this activity. Three sectors of cadaster had been selected for the detailing of the research. Thus, thematic maps had been elaborated, correspondents to you square them that enclose brownfields, combining the data of the videography images to the information of register in cadastre it and air photographs of 1978 and 1996. The techniques of Remote Sensoriament, in special the videografy, they had demonstrated effectiveness in the discrimination of urban targets and the characterization of the property. Had the high resolution of the images, the characteristics gifts in the lots easily had been discriminated, with a average of 92% of rightness between the three sectors, identifying 19 brownfields. Complementing the research, it had the application of questionnaire next to the population of the analyzed areas, aiming at to perceive the relation of the inhabitants with the abandoned sheds. On the basis of the mappings and results of the questionnaires had been elaborated proposals of brownfields revalorization,compatible with the local reality.
Doutor
Book chapters on the topic "Videography. eng"
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Scacco, Joshua M., and Kevin Coe. "Barack Obama." In The Ubiquitous Presidency, 81–110. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197520635.003.0004.
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This chapter analyzes Barack Obama’s administration in relation to the components of the ubiquitous presidency, especially how Obama adapted to the changing contexts of accessibility, personalization, and pluralism. It first tracks Twitter attention to Obama across seven years of his presidency, showing how attention spiked in relation to both traditional major addresses and newer approaches (e.g., his own tweets emphasizing elements of the ubiquitous presidency). The chapter then analyzes West Wing Week, a web series pioneered by the first official White House videographer, which takes the form of reality television and reveals the “backstage” of the presidency. Finally, the chapter uses semantic network analysis to track the relationship between the president, the press, and the public on Twitter in the context of the Affordable Care Act (commonly known as Obamacare). These relationships conform to the cascading activation model, in which presidential communication influences the terms used by the press and the public.
Conference papers on the topic "Videography. eng"
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Staymates, Matthew, Greg Gillen, Wayne Smith, Richard Lareau, and Robert Fletcher. "Flow Visualization Techniques for the Evaluation of Non-Contact Trace Contraband Detectors." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-31028.
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Efforts are underway in the Surface and Microanalysis Science Division at the National Institute of Standards and Technology to study trace aerodynamic sampling of contraband materials (explosives or narcotics) in non-contact trace detection systems. Trace detection systems are designed to screen people, personal items, and cargo for particles that have contaminated surfaces. In a typical implementation of people screening, a human subject walks into a confined space where they are interrogated by a series of pulsed air jets and are screened for contraband materials by a chemical analyzer. The screening process requires particle and vapor removal, transport, collection, desorption, and detection. Aerodynamic sampling is the critical front-end process for effective detection. In this paper, a number of visualization techniques are employed to study non-contact aerodynamic sampling in detail. Particle lift-off and removal is visualized using high-speed videography, transport of air and particles by laser light scattering, and desorption surface heating and cooling patterns by infrared thermography. These tools are used to identify sampling inefficiencies and may be used to study next-generation screening approaches for aerodynamic sampling of particles and vapors.
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Shekhawat, Yajuvendra Singh, Sameer Khandekar, and Pradipta Kumar Panigrahi. "Hydrodynamic Study of an Oscillating Meniscus in a Square Mini-Channel." In ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18322.
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Miniaturized fluidic systems like MEMS may involve single-phase or multi-phase flows with oscillations/ pulsations. Understanding the hydrodynamics of such flows can help in manipulating the performance parameters and improving the efficiency of micro-systems. This work focuses on hydrodynamics of a sinusoidally oscillating meniscus in a square mini-channel. The interfacial contact line behavior of a single oscillating meniscus formed between liquid slug and air, inside the square capillary tube, has been explored. An eccentric cam follower system has been fabricated to provide sinusoidal oscillations of fluid in the square glass capillary having hydraulic diameter of 2.0 mm. Experiments are conducted with two fluids, water and silicon oil. Dynamic contact angle measurements are carried out for water at two oscillating frequencies, 0.25 Hz and 0.50 Hz using high speed videography. It is seen that an increase in the oscillating frequency increases the difference in the advancing angle and receding angle of the meniscus, with the static contact angle of water on glass surface around 21°. For silicon oil the experiments have been performed at eight different frequencies in the range of 0.20 Hz and 1.00 Hz. It is seen that the meniscus is pinned at the extreme end of the stroke, unlike that in the case of water, and there is a film of silicon oil during oscillations. The thickness of the film formed increases with increase in oscillating frequency. There is considerable difference in the hydrodynamics of silicon oil and water.