Thematische Bibliographien / Pulsing light

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Auswahl der wissenschaftlichen Literatur zum Thema „Pulsing light“

Autor: Grafiati

Veröffentlicht am 25. Juni 2021

Zuletzt aktualisiert am 1. Februar 2022

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Zeitschriftenartikel zum Thema "Pulsing light"

Hashmi, Javad T., Ying-Ying Huang, Sulbha K. Sharma, Divya Balachandran Kurup, Luis De Taboada, James D. Carroll und Michael R. Hamblin. „Effect of pulsing in low-level light therapy“. Lasers in Surgery and Medicine 42, Nr. 6 (20.07.2010): 450–66. http://dx.doi.org/10.1002/lsm.20950.

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Chuntul, A. V., und A. P. Kozlovsky. „PULSING LIGHT STIMULATION IN STATE CORRECTION OF AVIATION PERSONNEL“. Aerospace and Environmental Medicine 52, Nr. 5 (2018): 47–52. http://dx.doi.org/10.21687/0233-528x-2018-52-5-47-52.

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Forestini, M., und C. Charbonnel. „Nucleosynthesis of light elements inside thermally pulsing AGB stars“. Astronomy and Astrophysics Supplement Series 123, Nr. 2 (Juni 1997): 241–72. http://dx.doi.org/10.1051/aas:1997348.

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Kamuri, Mohd, Zurina Zainal Abidin, Mohd Yaacob, Mohd Hamidon, Nurul Md Yunus und Suryani Kamarudin. „Separation and Detection of Escherichia coli and Saccharomyces cerevisiae Using a Microfluidic Device Integrated with an Optical Fibre“. Biosensors 9, Nr. 1 (14.03.2019): 40. http://dx.doi.org/10.3390/bios9010040.

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This paper describes the development of an integrated system using a dry film resistant (DFR) microfluidic channel consisting of pulsed field dielectrophoretic field-flow-fractionation (DEP-FFF) separation and optical detection. The prototype chip employs the pulse DEP-FFF concept to separate the cells (Escherichia coli and Saccharomyces cerevisiae) from a continuous flow, and the rate of release of the cells was measured. The separation experiments were conducted by changing the pulsing time over a pulsing time range of 2–24 s and a flow rate range of 1.2–9.6 μ L min − 1 . The frequency and voltage were set to a constant value of 1 M Hz and 14 V pk-pk, respectively. After cell sorting, the particles pass the optical fibre, and the incident light is scattered (or absorbed), thus, reducing the intensity of the transmitted light. The change in light level is measured by a spectrophotometer and recorded as an absorbance spectrum. The results revealed that, generally, the flow rate and pulsing time influenced the separation of E. coli and S. cerevisiae. It was found that E. coli had the highest rate of release, followed by S. cerevisiae. In this investigation, the developed integrated chip-in-a lab has enabled two microorganisms of different cell dielectric properties and particle size to be separated and subsequently detected using unique optical properties. Optimum separation between these two microorganisms could be obtained using a longer pulsing time of 12 s and a faster flow rate of 9.6 μ L min − 1 at a constant frequency, voltage, and a low conductivity.

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Barolet, Daniel, Pascale Duplay, Hélène Jacomy und Mathieu Auclair. „Importance of pulsing illumination parameters in low-level-light therapy“. Journal of Biomedical Optics 15, Nr. 4 (2010): 048005. http://dx.doi.org/10.1117/1.3477186.

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Begin, I., B. Bhatia, K. Rao, R. Keyston, J. T. Pierson, N. Neveu, F. Cote et al. „28PREGNANCIES RESULTED FROM GOAT NT EMBRYOS PRODUCED BY FUSING COUPLETS IN THE PRESENCE OF LECTIN“. Reproduction, Fertility and Development 16, Nr. 2 (2004): 136. http://dx.doi.org/10.1071/rdv16n1ab28.

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The procedure of nuclear transfer (NT) using somatic cells remains inefficient partly due to low fusion rates between donor cells and recipient ooplasm. Lectin is a glycoprotein which specifically binds to carbohydrates to induce a tight contact of membrane to membrane (Booth et al., 2001 Cloning and Stem Cells, 3, 139–159). The purpose of this study was to examine the fusion rates and developmental competence of NT embryos following pre-incubation of couplets in medium containing lectin prior to electrical pulsing. Oocytes were collected by laparoscopic ovum pick-up from hormonally primed goats or by aspiration from culled goat ovaries, and cultured for maturation at 38.5°C, 5% CO2. At approximately 24h after the onset of IVM, the cumulus cells were stripped off by brief vortexing in medium containing 0.2% hyaluronidase. Oocytes with first polar bodies were selected for NT. Successful enucleation was confirmed by the absence of MII chromosomes in ooplasm by means of brief exposure of the Hoechst 33342-stained oocytes to UV light. Three cumulus-granulosa cell lines from transgenic goats were used as donor cells. They were cultured to confluency in DMEM+20% FCS for 6 days prior to NT. Individual donor cells were transferred into the perivitelline space of the enucleated oocytes. Couplets were incubated for 15 minutes in TCM199+10% FCS containing 75 or 150μgmL−1 lectin (L-9132 Sigma, St.Louis, MO, USA) prior to being subjected to electrical pulsing (lectin treatment) with one DC pulse at 2.4kV/cm (1st pulsing). The fusion rate was determined 40–60 minutes after the 1st electric pulsing. Non-fused couplets were exposed to a 2nd pulsing. Approximately 30 minutes later, non-fused couplets were exposed to a 3rd pulsing. Couplets without the lectin treatment served as controls. Reconstructed embryos were activated with 5μM ionomycin followed by 5h of incubation in 10μgmL−1 cycloheximide with 7.5μgmL−1 cytochalasin B. A group of 10 to 13 embryos was transferred into a recipient after 12 to 14h of culture in G1.3. Statistical analysis was performed using the χ2 analysis. Results are shown in the following table. This study demonstrated that fusion rate could be improved by pre-incubating couplets in the medium containing 150μgmL−1 lectin prior to electrical pulsing and the embryos derived from the lectin treatment could establish the early pregnancies.

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Lee, Jong-Sung, Dae-Hee Lee, Sung-Jin Kim und Chang-Heon Oh. „An LED-based visible light communication system for multicast“. Indonesian Journal of Electrical Engineering and Computer Science 13, Nr. 1 (01.01.2019): 265. http://dx.doi.org/10.11591/ijeecs.v13.i1.pp265-271.

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<p>Visible Light Communication is a communication method that transmits data through light by pulsing an LED at high speed, performing broadcast communication for all devices existing in its coverage. Broadcast-based Visible Light Communication is limited to application to Internet of Things services, where various applications exist, although all receivers can communicate within the range of light sources. Therefore, this paper proposes an LED based Visible Light Communication system for multicast. The proposed system performs individual multicast by participating in communication only with receivers configured to use a specified ID value input at the transmitting side during data transmission. Experimental results show that the receiver can receive files individually according to a specified ID value.</p>

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Mous, D. J. W., J. Visser und R. G. Haitsma. „A nanosecond pulsing system for MeV light ions using a 2 MV TandetronTM“. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 219-220 (Juni 2004): 490–93. http://dx.doi.org/10.1016/j.nimb.2004.01.108.

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Corbet, R. H. D., M. J. Coe, K. E. McGowan, M. P. E. Schurch, L. J. Townsend, J. L. Galache und F. E. Marshall. „Properties of X-ray binaries in the Magellanic Clouds from RXTE and Chandra observations“. Proceedings of the International Astronomical Union 4, S256 (Juli 2008): 361–66. http://dx.doi.org/10.1017/s1743921308028718.

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AbstractThe X-ray binary population of the SMC is very different from that of the Milky Way consisting, with one exception, entirely of transient pulsating Be/neutron star binaries. We have now been monitoring these SMC X-ray pulsars for over 10 years using the Rossi X-ray Timing Explorer with observations typically every week. The RXTE observations have been complemented with surveys made using the Chandra observatory. The RXTE observations are non-imaging but enable detailed studies of pulsing sources. In contrast, Chandra observations can provide precise source locations and detections of sources at lower flux levels, but do not provide the same timing information or the extended duration light curves that RXTE observations do. We summarize the results of these monitoring programs which provide insights into both the differences between the SMC and the Milky Way, and the details of the accretion processes in X-ray pulsars.

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Bird, Jonathan C., und Marc H. Pinsonneault. „A BOUND ON THE LIGHT EMITTED DURING THE THERMALLY PULSING ASYMPTOTIC GIANT BRANCH PHASE“. Astrophysical Journal 733, Nr. 2 (09.05.2011): 81. http://dx.doi.org/10.1088/0004-637x/733/2/81.

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Dissertationen zum Thema "Pulsing light"

Uriri, Solomon Akpore. „A light-emitting-diode pulsing system for measurement of time-resolved luminescence“. Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/5788.

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A new light-emitting-diode based pulsing system for measurement of time-resolved luminescence has been developed. The light-emitting-diodes are pulsed at various pulse-widths by a 555-timer operated as a monostable multivibrator. The light-emitting-diodes are arranged in a dural holder connected in parallel in sets of four, each containing four diodes in series. The output pulse from the 555-timer is fed into an 2N7000 MOSFET to produce a pulse-current of 500 mA to drive the set of 16 light-emitting-diodes. This size of current is sufficient to drive the diodes with each driven at a pulse-current of 90 mA with a possible maximum of 110 mA per diode. A multichannel scaler is used to trigger the pulsing system and to record data at selectable dwell times. The system is capable of generating pulse-widths in the range of microseconds upwards.

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Myronidi, Despoina. „LIGHT-BEAT: REACTIVE LIGHT FOR THE EMOTIONAL COMFORT OF NEWBORN BABIES“. Thesis, KTH, Ljusdesign, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297961.

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This is a project-based thesis focusing on the investigation of topics related to human newborns and the factors found in their surrounding environment that need to be assessed so as to provide them with a feeling comfort. The objective is to boost their emotional development by the means of light in a close relation to sound so as to provide them with a type of intelligence allowing them to normally interact within a society during their adult life, reassuring social equality and eliminating potential social exclusion due to unexpected behaviours. After researching topics to have a better understanding of the newborn baby and its enclosing environment, a luminaire design solution -functioning with a reactive scheme performed with integrated sound sensors- provided further results to the main topic investigation. The conceptual scheme for the product development was inspired by the connection between the newborn and their life-giver, closely linked to the cross-modality of sensory development before and after birth. Additional results were obtained with light measurement assessments and a parent survey targeting both the intended light quality subjective evaluations and the marketing strength of the designed product. This survey was used -along with other means- as a design evaluation tool at the final stage of the design process. Potential further improvements as well as considerations for a distinct spatial application are discussed in the final part of the thesis. The sustainability aspect covered within this degree project is closely linked to good physical and mental health aspects, clean energy use and efficiency achieved by the integration of input sound sensors and controls, and conscious production and consumption by the proposal of low global footprint materials for the luminaire design. In the conclusions, an overall summary of the thesis outcomes is presented and further research is proposed regarding both the main topic investigation as well as a greater user category that can be related to the light metric assessments that were carried out for this research.

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Mentz, Jacobus Johannes. „A search for pulsating B-type variable stars in the southern open clusters NGC 6204 and Hogg 22 / Jacobus Johannes (Jaco) Mentz“. Thesis, North-West University, 2013. http://hdl.handle.net/10394/9520.

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The theory of stellar evolution and stellar structure relies on the observation of stars in di erent phases of their evolutionary cycle. The relation between observations and theory can be strengthened by obtaining observational data of a large sample of stars in a particular evolutionary phase. The search for Cephei stars, as conducted in this study, can contribute to the sample of known Cephei stars, where these interesting stars are massive non-supergiant early B-type stars, displaying pulsating behaviour which is not well understood. Stars tend to form in clusters where it can therefore be expected that young massive stars can be found in open clusters. For this reason two young southern open clusters were observed in order to search for B-type pulsating stars. The region of NGC 6204 and Hogg 22 was observed over a period of thirteen nights in Johnson B, V and I bands. NGC 6204 is believed to be the oldest cluster of the two at a distance of 0.8 kpc while the much younger Hogg 22 is more distant at 2.8 kpc. These two open clusters are located 6 arcminutes apart which made it possible to observe them simultaneously with a 12.8 12.8 arcminute eld of view. The observations were done with the newly installed 1600 telescope of the North-West University, South Africa. In order to do a variability search, periodic stars need to be identi ed from the cluster data, where a typical data set may contain thousands of scienti c images. In addition to the main motivation for this study, a pipeline was created in order to automate the photometry and data reduction processes. A Lomb-Scargle transform was applied to the stellar light curves in order to identify periodic sources. 354 signi cantly periodic stars were identi ed from the 3182 observed stars. Amongst them, two new possible Cephei stars were found together with a possible slowly pulsating B star (SPB), and numerous eclipsing binary systems. By using photometry of this region obtained by Forbes & Short (1996), instrumental magnitudes were transformed to a standard system in order to compare photometry results. From the constructed colour magnitude diagram of the two clusters, it could be seen that some stars, indicated by Forbes & Short (1996) to be cluster members, were in fact eld stars belonging to neither cluster. The reduction and photometry pipeline was implemented successfully on the data set, which also highlighted the importance of instrumentation and correct data analysis procedures. Possible improvements were identi ed in order to overcome di culties experienced during this study.
Thesis (MSc (Space Physics))--North-West University, Potchefstroom Campus, 2013

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Rúbal, Radek. „Hodnocení doby života a změn konfokální mikroskopií“. Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-221354.

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Content is focused on fluorescence lifetime imaging techniques. Fluorescence lifetime is computed from data acquired with using of Leica TCS SP8X confocal microscope sequential scanning. Algorithms and software for the computation, imaging and analysis of fluorescence lifetime is presented. Software is allowing both 2D and 3D imaging of fluorescence lifetime. Techniques are used for fluorescence lifetime imaging of mesenchymal cells and fibroblasts tainted with SPIO-Rhodamin complex.

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Liu, Hsien-Liang, und 劉軒良. „Power Efficiency Improvement for a Light Emitter Diode by Pulsing Power Drive“. Thesis, 2007. http://ndltd.ncl.edu.tw/handle/46435569171135104499.

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碩士
國立成功大學
機械工程學系專班
95
This thesis investigates how to utilize persistence of vision in combination with pulsing power drive to improve the efficiency of light emitter diode (LED) by experimental as well as analytical approaches. A series of experiments are first carried out to characterize the performances of LED and photodiode with various power input, frequency and duty cycle, followed by a comparison of photodiode and human eye observation. By analyzing the nonlinear response of system components and links between them, an analytical model is established and optimal pulsing parameters can be obtained. It is suggested that the optimal condition to efficiently drive a LED is to use maximum recommended operation current with minimum duty cycle while meeting the requirement of maximum intensity and minimum power requirement. From this study, it is concluded that pulsing power drive can substantially lower input power and improve the LED lighting efficiency.

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Chang, Ding-Cheng, und 張鼎成. „Applications of Period Search in Single-Band and Two-Band Light Curves for Pulsating Stars“. Thesis, 2012. http://ndltd.ncl.edu.tw/handle/21076242743145945807.

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碩士
國立中央大學
物理研究所
100
Period is one of the most important quantities in variable star research. Various methods exist in the literature to search for period for a given variable star, such as Lomb-Scargle periodogram, Phase Dispersion Minimization, SigSpec and etc. We compared three period search methods by using various pulsating stars with known periods given in the OGLE-III database, and found that SigSpec gave the highest success rate. Therefore, we have applied SigSpec to the light curves of variables in this thesis. In addition, we have developed a method to combine the V band and I band measurements into a single light curve to improve the time coverage of a classical pulsating star. The fundamental idea of our method is to use an empirical relation between the IV band amplitudes for a classical pulsating star, Amp(I)/Amp(V) ≃ 0.61 when combining the IV band light curves. In order to verify this empirical relation, we use Fourier decomposition technique to measure the amplitude ratios for classical pulsating stars found in the OGLE-III database. According to our numerical simulations, the combined light curves can improve the accuracy of period search when using SigSpec. For the pulsating variable stars having only a small number of measurements in IV bands, our method can improve their period searching results.

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Bücher zum Thema "Pulsing light"

Williams, Tyler, Anshu Malhotra und John Stratton Hawley, Hrsg. Text and Tradition in Early Modern North India. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199478866.001.0001.

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Early modern India—a period extending from the fifteenth to the late eighteenth century—saw dramatic cultural, religious, and political changes as it went from Sultanate, to Mughal, to early colonial rule. Witness to the rise of multiple literary and devotional traditions, this period was characterized by pulsating political energy and cultural vibrancy. Text and Tradition in Early Modern North India brings together recent scholarship on the languages, literatures, and religious traditions of northern India to highlight the importance of reconstructing multilingual literary histories. Focusing on the rise of vernacular languages, the volume underscores the manifold connections across regions, languages, communities, and traditions to reveal the diversity of literary and religious practices in this multilingual world. Analysing the emergence and development of literary cultures of north India, Text and Tradition also highlights processes of exchange and influence across these cultures. Spanning across various disciplines, the chapters here shed new light upon not only existing literary and religious traditions, but also those that may have disappeared but which should not be forgotten.

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Buchteile zum Thema "Pulsing light"

Richards, Todd L., und Juan Acosta-Urquidi. „Pulsing Magnetic Field Effects on Brain Electrical Activity in Multiple Sclerosis“. In Biologic Effects of Light 1998, 337–42. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-5051-8_55.

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Reid, Mark J., und Karl M. Menten. „Radio Photospheres: Imaging and Light Curves“. In Mass-Losing Pulsating Stars and their Circumstellar Matter, 283–90. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0139-7_66.

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Zerbi, Filippo M. „Simultaneous Light Curve, Color Curve and Line Profile Fitting for Pulsating Stars“. In Variable Stars as Essential Astrophysical Tools, 293–312. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-011-4299-1_11.

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Lynas-Gray, A. E., und D. Kilkenny. „The Light Curve of the Pulsating Extreme Helium Star Bd +13°3224: Further Evidence of a Decline in the Period Decrease Rate“. In Hydrogen Deficient Stars and Related Objects, 117–23. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4744-3_13.

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Sterken, C. „Pulsating variables“. In Light Curves of Variable Stars, 63–111. Cambridge University Press, 1996. http://dx.doi.org/10.1017/cbo9780511564796.004.

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J. Sullivan, Denis. „Analysis of Pulsating White Dwarf Star Light Curves“. In Standards, Methods and Solutions of Metrology. IntechOpen, 2019. http://dx.doi.org/10.5772/intechopen.86404.

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Konferenzberichte zum Thema "Pulsing light"

Chaika, Aleksander N., Nataliya L. Ivanova und Arkady P. Onokhov. „Pulsing record of the images and holograms on an optically addressed spatial-light modulator with highly sensitive layer of amorphous hydrogenated silicon“. In Second International Conference on Optical Information Processing, herausgegeben von Zhores I. Alferov, Yuri V. Gulyaev und Dennis R. Pape. SPIE, 1996. http://dx.doi.org/10.1117/12.262660.

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Kamagate, A., Ph Grelu, P. Tchofo-Dinda, J. M. Soto Crespo und N. Akhmediev. „Pulsating dissipative light bullets“. In 11th European Quantum Electronics Conference (CLEO/EQEC). IEEE, 2009. http://dx.doi.org/10.1109/cleoe-eqec.2009.5192929.

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Taherian, Shahab, Hamid Rahai, Jeremy Bonifacio, Samuel Lopez, Yong Lee, Behrouz Jafari und Thomas Waddington. „Computational Fluid Dynamics Validation of the Upper Respiratory System“. In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70187.

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Verification of numerical results with experimental data is an important aspect of any in silico study. In the case of the upper respiratory system, the air flow is often turbulent, which highlights the importance of validating an accurate turbulence model for numerical simulations. Patient specific CT based upper airway models were used for computational fluid dynamics (CFD) analyses of the upper respiratory system and the results were compared with the corresponding experimental results. Detailed CFD simulations were conducted using the STAR-CCM+ software to investigate the most appropriate numerical approach in accurately predicting flow characteristics in the upper respiratory system. Large Eddy Simulations (LES) and Reynolds-Averaged Navier-Stokes (RANS) equations with k-ε, and k-ω turbulence models were investigated. The experiments include simulating inspiratory-expiratory flow with particle injection at the intake. A stereolithographic (SL) system (3-D system Projet 6000HD), with a resolution of 0.001–0.002 inches per inch of part and VisiJet SL Clear material, was used for fabricating the experimental model. The outlet of the model was connected to a manifold, with subsequent connection to a piston-cylinder system where a computer-controlled motor was used to simulate the normal breathing flow conditions. Investigations of flow characteristics within the upper airway were performed with a 2-D µPIV system from Intelligent Laser Applications (ILA for micro particle image velocimetry) which includes a high power green LED light source with an effective area of 100×100 mm, and a pulsing system (LPS controller). Matlab software was used for the post processing of PIV images. The LES results displayed more detailed transient flow characteristics than the RANS results for both turbulence models. At the early time steps, the numerical results of the average velocity from all three methods were nearly identical. However, further downstream, where obstructions and strong velocity gradients exist, results differ with a larger velocity gradient near the wall for the LES simulation. Comparing the numerical and experimental results, due to seeding limitations, the experimental results did not display detailed low speed flow characteristics and thus, the shear stress and turbulence quantities were less than the corresponding CFD results. Further experiments are currently in progress to improve the experimental results and to better assess the transient numerical and experimental results.

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Serrano, J. R., H. Climent, P. Fajardo, M. A. Reyes-Belmonte und Fabrice Vidal. „Contribution to the Understanding of Cold Pulsating Flow Influence in the Efficiency of Small Radial Turbines for Turbochargers“. In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-68422.

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In the present paper an unsteady approach to determine the performance of a small radial inflow turbine working under cold pulsating flow is presented. It has been concluded that a reasonably good characterization of turbine behavior working with pulsating flow can be obtained using in a quasi-steady way models of the turbine isentropic efficiency and turbocharger mechanical efficiency. Both models have been fitted using data obtained from a steady flow characterization procedure. Turbocharger measured parameters from the cold pulsating flow campaign have been compared with the ones obtained from one-dimensional gas-dynamics computational modeling. The modeling approach is based on quasi-steady isentropic and mechanical efficiency models. Reasonably good accuracy in compressor and turbine variables prediction has been obtained for most of the operative conditions. Influence of amplitude and frequency of the pulsating flow over the instantaneous and average turbine efficiency has been studied to put some light on the analysis of the involved physical phenomena. The main conclusion is that the biggest effect of unsteady flow on turbine efficiency is through the influence on blade jet to speed ratio. It has been also concluded that for the same average blade to jet speed ratio pulses amplitude does not influence turbine efficiency when it is closed but yes at other VGT positions. The effect of pulses frequency is less evident and only influences VGT performance at the highest VGT openings.

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Ponti, F., V. Ravaglioli und M. De Cesare. „Estimation Methodology for Automotive Turbochargers Speed Fluctuations due to Pulsating Flows“. In ASME 2014 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icef2014-5580.

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Turbocharging technique, together with engine downsizing, will play a fundamental role in the near future as a way to reach the required maximum performance while reducing engine displacement and, consequently, CO2 emissions. However, performing an optimal control of the turbocharging system is very difficult, especially for small engines fitted with a low number of cylinders. This is mainly due to the high turbocharger operating range and to the fact that the flow through compressor and turbine is highly unsteady, while only steady flow maps are usually provided by the manufacturer. In addition, in passenger cars applications, it is usually difficult to optimize turbocharger operating conditions because of the lack of information about pressure/temperature in turbine upstream/downstream circuits and turbocharger rotational speed. This work presents a methodology suitable for instantaneous turbocharger rotational speed determination through a proper processing of the signal coming from an accelerometer mounted on the compressor diffuser or a microphone faced to the compressor. The presented approach can be used to evaluate turbocharger speed mean value and turbocharger speed fluctuation (due to unsteady flow in turbine upstream and downstream circuits), that can be correlated to the power delivered by the turbine. The whole estimation algorithm has been developed and validated for a light duty turbocharged Common-Rail Diesel engine mounted in a test cell. Nevertheless, the developed methodology is general and can be applied to different turbochargers, both for Spark Ignited and Diesel applications.

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Jarrahi, Mojtaba, Cathy Castelain und Hassan Peerhossaini. „Secondary Flow Velocity Field in Laminar Pulsating Flow Through Curved Pipes: PIV Measurements“. In ASME 2009 Fluids Engineering Division Summer Meeting. ASMEDC, 2009. http://dx.doi.org/10.1115/fedsm2009-78141.

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Effects of different parameters on the secondary flow pattern have been studied experimentally by particle image velocimetry (PIV) for a developing laminar pulsating flow through a circular curved pipe. The curvature ratio is η = rc/r0 = 11 and the curvature angle is 90°. As different secondary flow patterns formed by oscillation cause different transverse mixings, the enhancement of transverse mixing is investigated here. A T-shaped structure installed downstream of the curved pipe allowed PIV measurements obviating light diffraction effects. From knowledge of the velocity components of the secondary flow, the variation in axial vorticity (ξ) and transverse strain (ε) were calculated. The experiments were carried out for the range of stationary Reynolds numbers 420≤Rest≤1000 (corresponding to Dean numbers 126.6≤Dn≤301.51), velocity component ratios 1≤(β = Umax,osc/Um,st)≤4 and frequency parameters 8.37<(α = r0(ω/v)0.5)<24.5. To guarantee being in the laminar regime, the higher values of β (β = 3 and 4) were studied just for Rest = 420. The effects of each parameter ((Rest, β and α) on transverse mixing are discussed by comparing the dimensionless vorticities (|ζP|/|ζS|) and dimensionless transverse strains (|εP|/|εS|) during a complete oscillation period.

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Masanobu, Sotaro, Satoru Takano, Shigeo Kanada, Masao Ono und Hiroki Sasagawa. „Experimental Investigation of Large Particle Slurry Transport in Vertical Pipes With Pulsating Flow“. In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18194.

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Abstract For subsea mining, it is important to predict the pressure loss in oscillating pipes with pulsating flow for the safe and reliable operation of ore lifting. In the present paper, the authors focused on the pulsating internal flow in static vertical pipe and carried out slurry transport experiment to investigate the effects of flow fluctuation on the pressure loss. The alumina beads and glass beads were used as the solid particles in the experiment, and the fluctuating periods and amplitudes of pulsating water flow were varied. The time-averaged pressure losses calculated by the prediction method for the steady flow proposed in the past by the authors agreed well with the experimental ones. As for the fluctuating component of pressure loss, the calculation results using the quasi-steady expression of a mixture model were compared with the experimental data. The calculated results were different from experimental ones for alumina beads of which densities are almost same as those of the ores of Seafloor Massive Sulfides. It suggests that the expression is insufficient to predict the pressure loss for heavy solid particles. The calculated ones, however, provided those in the safety side. On the other hand, the calculated results for light solid particles such as glass beads agreed well with the experimental ones. It means that the expression would be applicable to the prediction of pressure loss for the mining of manganese nodules which are lighter than the ores of Seafloor Massive Sulfides.

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Louarn, Frederic, und Pandeli Temarel. „An Investigation of the Structural Dynamics of a Racing Yacht“. In SNAME 14th Chesapeake Sailing Yacht Symposium. SNAME, 1999. http://dx.doi.org/10.5957/csys-1999-010.

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The dynamic behaviour of a WOR 60 is investigated using three dimensional hydroelasticity theory. Global structural responses (e.g. stresses) in waves are obtained corresponding to the upright as well as to the more realistic heeled sailing configurations, revealing the connection between the ballast keel and the hull as being a critical area of the structure. For the "dry hull" analysis, a global finite element model has been developed, incorporating the hull and deck shell, the internal structure, the ballast keel and the rig together with rigging loads. The modular nature of the model has been used to assess the relative influence of each of the aforementioned components upon the required characteristic dynamic properties (e.g. natural frequencies and principal mode shapes). Regarding the "wet hull" analysis, a three dimensional Green's function technique, using pulsating sources distributed over the wetted surface, provides a numerical solution to the case of the yacht sailing in regular waves at arbitrary heading. Principal coordinates for the rigid body motions and flexible distortions of interest are evaluated and the latter are used to obtain the dynamic stresses in waves using modal summation. This paper will describe the modelling techniques used and discuss the applicability / limitations of hydroelasticity theory regarding this type of structures in the light of the results obtained for the upright and heeled operational conditions, as well as from the point of view of design aspects such as "L" and "T" keel configurations. The ABS design criteria will provide a practical reference for comparing the results from the dynamic analysis.

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Tomosawa, Fuminori, Shigeo Tsujikawa, Tadashi Ono, Keisuke Yonemaru, Shozo Takizawa, Yasuo Kugai und Norishige Minemura. „Research on Applicability of New Materials to Marine Structures in Tropical Climates: Durability Assessment of New Materials“. In 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92110.

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New structural members that are light and durable are anticipated to reduce the running and maintenance costs of structures exposed to harsh marine environments, such as offshore oil production facilities, thereby reducing their lifecycle cost. This study aims to investigate the applicability of new materials to marine structures, focusing on their durability. To this end, a 5-year exposure test has been conducted beginning in 1999 on 3 types of specimens (for corrosion observation, tension testing, and joint strength testing) made of 21 selected materials (6 nonferrous metals, 8 steels, 4 composite materials, and 3 rope materials). The specimens have been exposed at 3 sites: Okinotori-shima and Miyako-jima, corrosive environments with high temperature and humidity, and a thermo-hygrostatic room in a laboratory. Having completed the natural exposure tests in 2004, the authors conducted strength tests and observation thereafter toward 2005. This paper summarizes the results of such tests and observation conducted so far, while making a final assessment of each material, and refers to the tasks ahead based on these results. No marked differences were observed between the results of exposure at Okinotori-shima and Miyako-jima. Both islands were therefore found to be similar environments in terms of corrosion. The corrosion states of specimens were classified into five Categories: I (no corrosion), II (slight corrosion), III (light corrosion), IV (corrosion with strength loss), and V (corrosion with significant strength loss). Only reference specimens of ordinary steel were designated as Category V. Those designated as Category IV included textile ropes and Ni steel and coated steel panels with damaged coating film. Most other new materials were designated as Categories III or less with no strength losses. Materials designated as Categories I to III were subjected to surface observation using optical and electron microscopes and element distribution analysis over a cross section using an electron beam probe microanalyzer. The progress of corrosion in each material over the five years has thus been elucidated. Within the range of the 5-year exposure test, most of the selected new materials pose no problems in regard to durability. However, marine structures are more vulnerable to alternate stresses than general structural members on land because of constant waves and pulsating gales on the sea. The authors intend to investigate the durability of structural members under continued or cyclic stress as a subject for the future.

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Kockmann, Norbert, Craig Holvey und Dominique M. Roberge. „Transitional Flow and Related Transport Phenomena in Complex Microchannels“. In ASME 2009 7th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2009. http://dx.doi.org/10.1115/icnmm2009-82139.

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In microchannels with typical dimensions from 10 μm to few hundreds μm, the flow is dominated by viscous forces, leading often to laminar flow conditions. At the entrance or in bends and curves, where the flow is accelerated or changes its direction, inertial forces generate transverse flow velocities. Due to continuity, compensating transverse velocity components generate vortex pairs, such as Dean flow in circular bends. The flow is still laminar, steady, and shows no statistically distributed fluctuations typical for turbulent flow. This deviation from straight laminar conditions, often in larger channels (100 μm to few mm) or for higher flow rates, is called transitional flow. That embraces the first occurrence of pulsating vortices, period doubling of vortex pairs, flow bifurcation, and regularly fluctuating wake flow or vortex shedding. With increased flow velocity, this process leads to chaotic flow phenomena being first evidence of turbulence. This paper describes the transitional flow characteristics in single channel elements such as bends and T-junction as well as around fins and posts in channels. These elements are used to augment the transport characteristics in microchannels for enhanced heat and mass transfer and for performing chemical reactions in microreactors. The profound understanding of the flow characteristics is fundamental for the understanding of transport phenomena. Additionally, this knowledge can be used to design successful microstructured devices for various applications by knowing how to generate and control vortices in microchannels. Concepts from chaotic advection are presented here to describe vortex flow and related transport characteristics. Though recent advances has shed new light on transport phenomena in complex channel structures, many issues are still unknown and huge potential is hidden in optimized channel devices.

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