Letteratura scientifica selezionata sul tema "Continous blowing"
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Articoli di riviste sul tema "Continous blowing"
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McCulloch, John G. "The History of the Development of Melt Blowing Technology". International Nonwovens Journal os-8, n. 1 (marzo 1999): 1558925099OS—80. http://dx.doi.org/10.1177/1558925099os-800123.
Testo completoAbstract (sommario):
Almost a half century ago development efforts were initiated by very different entities, in widely different locations, to demonstrate one step processes to convert polymer to web: • Major fiber producers (DuPont, Freudenberg, Monsanto) began work on converting polymer (PE, PET, Nylon) into continuous “cold drawn” filaments and integrating the conversion of these filaments into a random-laid bonded nonwoven fabric. • An oil company (Exxon), building on the earlier work (1950's) of the Naval Research Labs to produce fine fibers, began work on converting their recently commercialized PP polymer into discontinuous, or continuous, “hot drawn” filaments and integrating these filaments into a random-laid self bonded nonwoven web having average fiber sizes 2–5 microns (fine fibered webs) to 100+ fibers (coarse fibered webs). As a result of these early development efforts, three different, but related melt spinning nonwoven processes have achieved significant commercial importance, with tremendous benefits to consumers worldwide: • Spunbond process • Melt blowing process • Flash spinning process This presentation will summarize the development of the melt blowing process from conceptualization to current state-of-the-art. Important product, process and equipment developments are detailed in the 50 year growth of the melt blowing process from a laboratory concept to a 125 million pound a year U.S. and Canadian commercial business and substantial additional worldwide consumption. Today, spunbond and melt blown processes are used for approximately 54% of the total 18.6 million square yards U.S. nonwoven market.
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Margaris, P., e I. Gursul. "Wing tip vortex control using synthetic jets". Aeronautical Journal 110, n. 1112 (ottobre 2006): 673–81. http://dx.doi.org/10.1017/s0001924000001536.
Testo completoAbstract (sommario):
AbstractAn experimental investigation was conducted to study the effect of synthetic jet (oscillatory, zero net mass flow jet) blowing near the wing tip, as a means of diffusing the trailing vortex. Velocity measurements were taken, using a Particle Image Velocimetry system, around the tip and in the near wake of a rectangular wing, which was equipped with several blowing slots. The effect of the synthetic jet was compared to that of a continuous jet blowing from the same configurations. The results show that the use of synthetic jet blowing is generally beneficial in diffusing the trailing vortex and comparable to the use of continuous jet. The effect was more pronounced for the highest blowing coefficient used. The driving frequency of the jet did not generally prove to be a significant parameter. Finally, the instantaneous and the phase-locked velocity measurements helped explain the different mechanisms employed by the continuous and synthetic jets in diffusing the trailing vortex.
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Yang, Chenghao, Elias J. G. Arcondoulis, Yannian Yang, Jing Guo, Reza Maryami, Chuanxing Bi e Yu Liu. "Active control of airfoil turbulent boundary layer noise with trailing-edge blowing". Journal of the Acoustical Society of America 153, n. 4 (aprile 2023): 2115–30. http://dx.doi.org/10.1121/10.0017787.
Testo completoAbstract (sommario):
Large Eddy Simulation (LES) and Ffowcs Williams-Hawkings acoustic analogy are performed to study the effect of trailing-edge blowing on airfoil self-noise. Simulations were conducted using a National Advisory Committee for Aeronautics 0012 airfoil at zero angle of attack and a chord-based Reynolds number of [Formula: see text]. The aerodynamic and aeroacoustic characteristics of the baseline airfoil were thoroughly verified by comparison with previous numerical and experimental data. The noise reduction effects of continuous and local blowing with different blowing ratios and blowing momentum coefficients were compared. A maximum noise reduction of 20 dB was achieved via trailing-edge blowing and the noise reduction mechanisms of the two blowing methods were discussed. The LES results show a pair of recirculation bubbles in the airfoil wake which are suppressed by trailing-edge blowing. As the blowing vortices convect into the wake, they stretch and stabilize the shear flows from airfoil surfaces. Instantaneous vorticity and root mean square velocity fluctuations are also weakened. There is a decrease in the spanwise coherence and an increase in the phase difference, which contribute to noise reduction. It is concluded that the suppression of turbulence fluctuations in the near wake is the main mechanism of noise reduction for airfoil trailing-edge blowing.
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Li, Wenjie, Shibo Wang, Jianxin Xu, Jianhang Hu, Hua Wang, Yuling Zhai, Qingtai Xiao, Ge Deng e Dongbo Li. "Numerical Investigation of the Enhanced Stirring Characteristics of a Multi-Lance Top-Blowing Continuous Converting Furnace for Lance Arrangement and Variable-Velocity Blowing". Energies 16, n. 5 (2 marzo 2023): 2412. http://dx.doi.org/10.3390/en16052412.
Testo completoAbstract (sommario):
Oxygen lances are key equipment for copper converters. The effect of the lance arrangement on the mixing of a gas–slag two–phase is discussed using numerical simulation and experimental verification with a water model, and the stirring characteristics enhanced by variable–velocity blowing are explored. The results showed that the single–row lance arrangement (SA) increased the average velocity in the slag phase by 17.93% and reduced the disturbance to the metal phase by 27.78% compared to the double–row lance arrangement (DA). Compared to the constant–velocity blowing system (CSB), the sine–wave blowing system (SWB) and rectangular–wave blowing system (RWB) increased the average velocity in the slag phase by 24.03% and 13.96%, respectively, and reduced the proportion of the low–velocity area by more than 46.2%. The velocity imbalance in the SA local area enhances the mixing of the gas–slag two–phase. The variable–speed blowing improves the mass transfer and mixing effect.
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Meijie, Z., G. Huazhi, H. Ao, Z. Hongxi e D. Chengji. "Numerical simulation and industrial practice of inclusion removal from molten steel by gas bottom-blowing in continuous casting tundish". Journal of Mining and Metallurgy, Section B: Metallurgy 47, n. 2 (2011): 137–47. http://dx.doi.org/10.2298/jmmb110120006m.
Testo completoAbstract (sommario):
Gas blowing at the bottom of tundish is an efficient metallurgy technique in clean steelmaking. In this paper, the removal of small size inclusions in the gas bottom-blowing tundish was studied by numerical simulation and industrial practice. The residence time distribution (RTD) of molten steel in the tundish was calculated by mathematical modeling. The content of small size inclusions in the slab was analyzed using a oxygen probing and metallographic images. The results show that the molten steel characteristics obviously change when applied gas bottom-blowing, the average residence time of molten steel in the tundish prolongs more than 100s and the dead volume fraction decreases about 5%. Therefore, the removal efficiency of small size inclusions greatly increases because of bubbles attachment and long moving path. Industrial experiment results show that the average inclusions content of less than 20?m decreases more than 24%, the average overall oxygen content decreases about 15% when controlling the reasonable blowing parameters.
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Sugiura, Konosuke, e Tetsuo Ohata. "Large-scale characteristics of the distribution of blowing-snow sublimation". Annals of Glaciology 49 (2008): 11–16. http://dx.doi.org/10.3189/172756408787814960.
Testo completoAbstract (sommario):
AbstractTo consider the large-scale characteristics of blowing-snow sublimation and its importance in the hydrological cycle in the cryosphere, we investigated the sublimation of blowing snow particles on a global scale using the global datasets of the European Centre for Medium-RangeWeather Forecasts (ECMWF) re-analysis data and the International Satellite Land Surface Climatology Project (ISLSCP) Initiative I data for 1987. The sublimation fluxes of blowing snow particles were estimated globally with 2.5˚ resolution at 6 hour intervals. We found that the sublimation of blowing snow particles occurs more widely in the Northern Hemisphere than in the Southern Hemisphere, does not increase monotonously with latitude, and becomes more active in the polar coast regions and highlands, although the annual mean sublimation fluxes of the Northern and Southern Hemispheres are almost equal. In addition, we confirmed the characteristic seasonal changes in the area of sublimation in the Northern Hemisphere. Although we need to incorporate continuous parameters from systematic ground-based studies of the structure of blowing snow in specific fields to reduce uncertainty regarding the characteristics of blowing snow, our results point to a need to review the current understanding of the hydrological cycle.
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Ayuni, Farihah, Gina Selvia Rahayu, Nesty Ermin Nadhirah, Tegar Selaras Gustavisiana e Hisny Fajrussalam. "Perspektif Islam terhadap “Kaum Majusi” Modern". YASIN 3, n. 3 (7 maggio 2023): 342–51. http://dx.doi.org/10.58578/yasin.v3i3.1080.
Testo completoAbstract (sommario):
In this modern era, we often encounter celebrations by blowing out candles as part of the event. This continues to develop and grow into a culture in society. As for Islam, it strictly prohibits a celebration in which there is uproar and blowing out candles as the culmination of the event because it seems to have cultivated the habits of the former Magi. However, some other Muslims actually think that blowing out candles at a celebration is a sign of gratitude. This research is aimed at analyzing how many people cultivate candle blowing in celebrations and how Muslims view blowing candles at a celebration because this problem reaps pros and cons from Muslims themselves. The methods to be used in this research are qualitative and quantitative methods, considering the level of direct data requirement for this research.
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Wang, Dazhi, Fang Gao, Lidong Xing, Jianhua Chu e Yanping Bao. "Continuous Prediction Model of Carbon Content in 120 t Converter Blowing Process". Metals 12, n. 1 (14 gennaio 2022): 151. http://dx.doi.org/10.3390/met12010151.
Testo completoAbstract (sommario):
A continuous prediction model of carbon content of 120 t BOF is established in this paper. Based on the three-stage decarburization theory and combined with the production process of 120 t converter, the effects of oxygen lance height and top blowing oxygen flow rate are also considered in the model. The explicit finite difference method is used to realize continuous prediction of carbon content in the converter blowing process. The model parameters such as ultimate carbon content in molten pool are calculated according to the actual data of 120 t BOF, which improves the hit rate of the model. Process verification and end-point verification for the continuous prediction model have been carried out, and the results of process verification indicate that the continuous prediction model established in the paper basically accords with the actual behavior of decarburization. Moreover, the hit ratio of the continuous prediction model reached 85% for the prediction of end-point carbon content within a tolerance of ±0.02%.
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Yoshinaga, Etsuo. "Blow Analytic Mappings and Functions". Canadian Mathematical Bulletin 36, n. 4 (1 dicembre 1993): 497–506. http://dx.doi.org/10.4153/cmb-1993-065-1.
Testo completoAbstract (sommario):
AbstractLet π: M —> Rn be the blowing-up of Rn at the origin. Then a continuous map-germ f: (Rn — 0,0) —> Rm is called blow analytic if there exists an analytic map-germ such that Then an inverse mapping theorem for blow analytic mappings as a generalization of classical theorem is shown. And the following is shown. Theorem: The analytic family of blow analytic functions with isolated singularities admits an analytic trivialization after blowing-up.
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Zhang, M. J., H. Z. Gu, A. Huang, H. X. Zhu e C. J. Deng. "Physical and mathematical modeling of inclusion removal with gas bottom-blowing in continuous casting tundish". Journal of Mining and Metallurgy, Section B: Metallurgy 47, n. 1 (2011): 37–44. http://dx.doi.org/10.2298/jmmb1101037z.
Testo completoAbstract (sommario):
Gas blowing at the bottom of tundish is an efficient metallurgy technique in clean steelmaking and has been widely concerned. In this paper, spherical alumina particles were selected to model inclusions, 1:3 scale model was utilized, the removal efficiency of inclusions with the gas bottomblowing in the tundish was studied by physical and mathematical modeling. The mathematical model is validated by comparing the predicted and measured residence time distributions and dye flow patterns of tracer. The results show that while the removal efficiency of large size particles has no obvious changes, the gas bottom-blowing has great contribution to the removal of small particles.
Tesi sul tema "Continous blowing"
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Ammam, Tarek. "Development of innovative solutions for the control of the aerodynamic drag induced by cavity flows : Application to the reduction of railway energy consumtion". Electronic Thesis or Diss., Valenciennes, Université Polytechnique Hauts-de-France, 2024. http://www.theses.fr/2024UPHF0011.
Testo completoAbstract (sommario):
Ce travail concerne l’analyse et le contrôle de l’écoulement affleurant des cavités présentant la particularité d’être ouvertes latéralement et à proximité d’une paroi, avec pour visée applicative le développement de solutions de contrôle de la trainée induites par les cavités bogie de trains à grande vitesse. Pour étudier cette configuration, représentative des cavités ferroviaires et réputée moins sensible au bruit acoustique que les cavités présentant des rapports d’aspect plus petits, des essais expérimentaux ainsi que des simulations numériques (IDDES) d’accompagement ont été entrepris. Les motivations de nos recherches portent sur l’identification des liens entretenus entre l’écoulement et les charges aérodynamique appliquées sur la cavité d’une part et sur le contrôle de la trainée induite d’autre part. Dans ce cadre des essais synchronisés PIV-pression pariétales ont été spécifiquement menés en complément des mesures de forces visant à quantifier la contribution à la traînée (donc à la résistance à l’avancement) de la cavité. Ces derniers développements nous ont également permis d’identifier et de paramétrer une solution de contrôle actif par soufflage continu, basée sur la réduction de la quantité de mouvement à l’interface de la cavité et de débit sous caisse. Les gains de traînée maximum associés sont de l’ordre de 20% pour une géométrie de cavité vide et de l’ordre de 15% pour une cavité avec son bogieThis work concerns the analysis and control of the flow over cavities, which have the particularity of being laterally open and near a wall, with the aim of developing drag control solutions induced by bogie cavities of high-speed trains. To study this configuration, representative of railway cavities and known to be less sensitive to acoustic noise than cavities with smaller aspect ratios, experimental tests and numerical simulations (IDDES) were conducted. The motivations of our research focus on identifying the relationships between the flow and the aerodynamic loads applied on the cavity on one hand, and on the control of induced drag on the other hand. In this context, synchronized PIV-wall pressure tests were specifically conducted in addition to force measurements aimed at quantifying the contribution to drag (and thus to resistance to motion) of the cavity. These recent developments also allowed us to identify and parameterize a continuous blowing active control solution, based on reducing momentum at the cavity interface and underbody flow rate. The maximum associated drag reductions are around 20% for an empty cavity geometry and around 15% for a cavity including the bogie
2
TSAI, MAO-CHANG, e 蔡茂昌. "The Effect of Bottom Blowing Conditions on Floating Inclusion Behavior in the Vacuum Continuous Casting Process by Water Modeling". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/10856600199584215391.
Testo completoAbstract (sommario):
碩士義守大學
材料科學與工程學系碩士班
95
This research aims at enhancing the quality of melting metal solution in the vacuum continuous casting by using air blowing and floating inclusion to remove the nonmetallic impurity. Modify the air blowing in melting process by water model. Analyze the behavior of air bubbles to find the optimum parameters. In this experiment we made an Id112mm*H200mm acrylic water model. Confirm the similarity between the cold model and the hot model by the Buckingham theorem. Set the parameters of the water model experiment. Substitute copper melting by water and argon by air. Modify the real air blowing to float inclusion of hot model by water model. This research is divided into the static experiment and dynamic tests. (1)Static experiment：Without water entering from the water mold. Change the number of tuyeres (1~4) the tube, the liquid level (40, 80, 120mm), the air flow rate (1.0~2.5L/min) to analyze the influence of air bubble movement behavior by the tubes arrangement , the air bubble size, the air bubbles density of distribution. Estimate the optimum parameters combination. (2)Dynamic experiment：With water entering from the top of water mold and leaving from the bottom respectively. Modify the air blowing to float inclusion process whether the air bubble sink down to bottom and induce the flaw. (1) Result of static experiment: 1.With liquid level 80mm, four tuyeres, gas flowing rate below 1.5 L/min can make bubble size smaller and even. The air bubble flow field is stable and the turbulence of liquid surface may decrease. 2. With liquid level 80mm, 2 tuyeres, the gas flowing rate must be below 1.0 L/min. Converts in the actual casting system the optimum floating inclusion condition is:1. Melted fluid level is 80mm. The tuyere number is four. The argon flow rate must be below 6.67 L/min. 2. Melted fluid level is 80mm. The tuyere number is two. The argon flow rate must be below 4.44 L/min. (2) Result of dynamic test : The quantity of sinking air bubble is 0 %, that means that in the real casting process all air bubble float is upward. No air bubble will flow back to the flow channel.
Libri sul tema "Continous blowing"
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Godøy, Rolf Inge. Key-postures, trajectories and sonic shapes. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199351411.003.0002.
Testo completoAbstract (sommario):
The focus of this chapter is on how our notions of shape in music emerge from experiences of sound-producing body motion such as hitting, stroking, bowing, shaking or blowing. Sound-producing body motion is seen as organized around postures at salient moments in the music, around so-called key-postures, and as making continuous trajectories between these key-postures. It is suggested that our experiences of both making and seeing such key-postures and continuous trajectories in sound-producing body motion link the sonic and visual elements in music, meaning that body motion strongly contributes to our notions of shape in music.
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Hong, Yu. Forging Broadband for the Commanding-Heights Economy. University of Illinois Press, 2017. http://dx.doi.org/10.5406/illinois/9780252040917.003.0004.
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To explicate the ascent of the internet into a primary site of economic restructuring, this chapter historicizes broadband internet in China, focusing on the evolving political economy of networks after the neoliberal reform. It argues that the take-up of broadband took place when China’s outward-looking economy has become full blown and crisis-ridden. In this new context and especially after 2008, broadband is interwoven into the state’s manifold thrusts of constructing for an alternative commanding-height economy. However, new contradictions, which the broadband China program fell short of addressing, including labor discontent, excessive competition in the urban access market, and corporate disincentives to expanding networks in the countryside, continue to hamper broadband from becoming the strategic public infrastructure that state leaders hope to make it.
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Pitts-Taylor, Victoria, a cura di. Cultural Encyclopedia of the Body. Greenwood, 2008. http://dx.doi.org/10.5040/9798400635014.
Testo completoAbstract (sommario):
Pop culture and the media today are saturated with the focus on the aesthetics of the human body. Magazines and infotainment shows speculate whether this or that actress had breast implants or a nose job. Americans are not just focusing on celebrities but on themselves too and today have unprecedented opportunities to rework what nature gave them. One can now drop in to have cosmetic surgery at the local mall. Contemplating the superficial nature of it all grows tiresome, and pop culture vultures and students can get a better fix for their fascination with the body beautiful through the cultural insight provided in this amazing set.Cultural Encyclopedia of the Bodyis a treasure trove of essays that explore the human body alphabetically by part, detailing practices and beliefs from the past and present and from around the world that are sometimes mind-blowing and eye-popping. Body parts are examined through a multifaceted cultural lens. Readers will explore how the parts are understood, what they mean to disparate societies, how they are managed, treated, and transformed, and how they are depicted and represented. The entries draw from many disciplines that are concerned to some degree or another with human bodies, including anthropology archeology, sociology, religion, political history, philosophy, art history, literary studies, and medicine. The encyclopedia proffers information on a number of cultures, tribes, and customs from East and West. Ancient practices to the latest fad, which in fact might continue ancient practices, are illuminated. Other considerations that arise in the essays include comparisons among cultures, the changing perceptions of the body, and issues of race, gender, religion, community and belonging, ethnicity, power structures, human rights.
Capitoli di libri sul tema "Continous blowing"
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Wang, Songsong, e Xueyi Guo. "Thermodynamic Modeling of Oxygen Bottom-Blowing Continuous Converting Process". In The Minerals, Metals & Materials Series, 573–83. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-95022-8_45.
Testo completo
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Ren, Yong, Shuai Niu, WenCai Li e Xin Hong. "Experimental Research of Continuous Temperature Measurement for Molten Metal Bath through Bottom-Blowing Component". In EPD Congress 2014, 277–83. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118889664.ch32.
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Kumar, A. R., K. M. Henderson e S. Schafrik. "Scale modeling, PIV, and LES of blowing type airflow in a deep cut continuous coal mining section". In Mine Ventilation, 65–74. London: CRC Press, 2021. http://dx.doi.org/10.1201/9781003188476-7.
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Hartquist, T. W., J. E. Dyson e D. P. Ruffle. "Some Other Windy And Explosive Sources". In Blowing Bubbles In The Cosmos, 142–50. Oxford University PressNew York, NY, 2004. http://dx.doi.org/10.1093/oso/9780195130546.003.0011.
Testo completoAbstract (sommario):
Abstract Though in previous chapters we have addressed a large variety of astronomical objects and phenomena, we have by no means examined all of the types of environments in which winds and explosions occur. The present chapter contains brief descriptions of several classes of windy and explosive sources upon which we have either touched only briefly or which we have not yet mentioned. In the closing section of chapter 5 on low-mass young stellar objects, we gave some hint that outflows from such sources are not continuous. However, we did not examine the FU Orionis phenomenon, named after the prototypical source in which it occurs. The FU Orionis phase is one of exceptionally high brightness and mass loss for a LMYSO.
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Skowronski, Michael J., Michael R. Huspek e Camilla Righi. "Alternative Blowing Agent Solutions for Polyisocyanurate Continuous Laminate Metal Panels". In Polyurethanes Expo 2001, 97–106. CRC Press, 2020. http://dx.doi.org/10.1201/9780429332609-16.
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"Last Days with Chronic Obstructive Pulmonary Disease". In Respiratory Symptoms, a cura di Margaret L. Campbell, 119—C14P40. Oxford University PressNew York, 2023. http://dx.doi.org/10.1093/med/9780190098896.003.0014.
Testo completoAbstract (sommario):
Abstract Patients in the last days of chronic obstructive pulmonary disease struggle with continuous dyspnea and activity intolerance. Preparing them for dying while focusing on symptom management requires compassion and skill. Adjusting medication routes of administration allows continued use of bronchodilators and anticholinergics. A tabletop fan blowing toward the face increases air flow. Upright positioning in a recliner or a hospital bed increases vital capacity. Pacing and moderating activities minimizes dyspnea exacerbation. Family members often have the capacity to apply these techniques. This chapter also discusses the eligibility criteria for hospice enrollment when the patient’s diagnosis is end-stage chronic obstructive pulmonary disease.
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Hyde, Peter, e Alex Mahalov. "Bowing Sand, Dust, and Dunes, Then and Now–A North American Perspective". In Deserts and Desertification. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.98337.
Testo completoAbstract (sommario):
Dune fields of the present day, the Dust Bowl disaster of the 1930s U.S. Great Plains, and contemporary efforts to forecast, simulate, and understand dust storms have a striking, uniform commonality. What these apparently diverse phenomena have in common is that they all result from blowing sand and dust. This review paper unifies these three disparate but related phenomena. Its over-arching goal is to clearly explain these manifestations of windblown sand and dust. First, for contemporary dune fields, we offer reviews of two technical papers that explain the eolian formation and the continuing development of two major dune fields in southeastern California and northwestern Sonora, Mexico: the Algodones Dunes and the Gran Desierto de Altar. Second, historical, geological, meteorological, and socioeconomic aspects of the 1930s Great Plains Dust Bowl are discussed. Third, and last, we return to the present day to summarize two lengthy reports on dust storms and to review two technical papers that concern their forecasting and simulation. The intent of this review is to acquaint the interested reader with how eolian transport of sand and dust affects the formation of present-day dune fields, human agricultural enterprises, and efforts to better forecast and simulate dust storms. Implications: Blowing sand and dust have drastically affected the geological landscape and continue to shape the formation of dune fields today. Nearly a century ago the U.S. Great Plains suffered through the Dust Bowl, yet another consequence of blowing sand and dust brought on by drought and mismanagement of agricultural lands. Today, this phenomenon adversely affects landscapes, transportation, and human respiratory health. A more complete understanding of this phenomenon could (and has) led to more effective mitigation of dust sources, as well as to a more accurate predictive system by which the public can be forewarned.
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D'Agostino, Susan. "Abandon perfectionism, because of the Hairy Ball Theorem". In How to Free Your Inner Mathematician, 131–36. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198843597.003.0023.
Testo completoAbstract (sommario):
“Abandon perfectionism, because of the Hairy Ball Theorem” explains the mathematics behind the Hairy Ball Theorem, including a basic introduction to topological equivalence, vectors, and continuous vector fields. The discussion is illustrated with numerous hand-drawn sketches. Readers will understand the meaning of mathematical sayings arising from the theorem, including, “you can’t comb a hairy ball,” “every cow has a cowlick,” and “there is always one place on Earth where the wind is not blowing.” Mathematics students and enthusiasts are encouraged to let the Hairy Ball Theorem serve as a reminder that perfection in mathematics and life is often an impossible goal and that it is often enough, maybe even desirable, to do one’s very best. At the chapter’s end, readers may check their understanding by working on a problem. A solution is provided.
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Halmi, Katherine A. "Eating disorders". In Pediatric Psychopharmacology: Principles and Practice, 592–604. Oxford University PressNew York, NY, 2002. http://dx.doi.org/10.1093/oso/9780195141733.003.0044.
Testo completoAbstract (sommario):
Abstract Eating disorders are best conceptualized as syndromes, which are classified on the basis of the clusters of symptoms they present. The two major and bestdocumented eating disorders, anorexia nervosa (AN) and bulimia nervosa (BN), are best understood with a multidimensional model. In this model these disorders begin with dieting, and behaviors and influences antecedent to the dieting experience propel the symptoms into a full-blown eating disorder. The antecedent conditions consist of biological vulnerability, psychological predisposition, and social influences. As the dieting continues, starvation effects, weight loss, nutritional effects, and psychological changes occur. Both psychological and physiological reinforcements of the maladaptive eating behavior continue a cycle of the core dysfunctional eating behaviors. The numerous treatment approaches for AN and BN reflect studies representing the various categories of this multidimensional model for eating disorders. (Halmi, 1994).
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"Epilogue". In Fire Dreams, 210–24. Duke University Press, 2024. http://dx.doi.org/10.1215/9781478027690-007.
Testo completoAbstract (sommario):
The epilogue begins with WWAV’s thirtieth-anniversary celebrations in 2019, as we come together with our local, national, and international community to honor the vision that our foremothers had in 1989 and the worlds we have made together at the intersections of Black feminist struggle ever since. Our Existence is Political. We continue to reflect on the stories and the practices that made possible WWAV’s rising from the ashes. We also take stock of the new futures that have been written since our research as survival formally concluded in 2016. In 2022, as we approach the tenth anniversary of the arson attack, our country is burning. It is hardly the first time. We ask how we can be accomplices in bringing into being more livable futures by blowing on the creative and life-giving embers that are already smoldering around us.
Atti di convegni sul tema "Continous blowing"
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Nonomura, Taku, Satoshi Sekimoto, Kengo Asada, Akira Oyama e Kozo Fujii. "Experimental Study of Blowing Direction Effects of DBD Plasma Actuator on Separation Control of Flow Around an Airfoil". In ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-15010.
Testo completoAbstract (sommario):
An experimental study of plasma actuator on separation control is conducted. The plasma actuator is used for control of separated flow around NACA0015 airfoil. The Reynolds number based on chord length is set to 60,000 and the angle of attack is set to 12[deg]. The plasma actuator is applied with normal mode and burst mode, where normal mode denotes continuous actuation and burst mode denotes temporary intermittent actuation. Also, actuations for co-flow blowing and counter blowing are conducted. The averaged pressure coefficients of wing surface and velocity fields are measured. For velocity fields, PIV measurement is adopted. Comparing counter and co-flow blowings of plasma actuator, the effects of counter blowing is investigated. Also, for both co-flow and counter blowing cases, we investigate the effects of burst mode. Through the series of experiments, following two types of mechanism for separation control will be discussed. One type is considered to be directly giving momentum in the boundary layer which seems to be more active in co-flow blowing with normal mode. The other type is considered to be enhancement of the mixing, leading to increase in momentum thickness of the boundary layer. The latter mechanism seems to be active in the burst mode with both co-flow and counter blowing.
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Kornilov, V. I., e E. A. Shkvar. "Turbulent boundary layer on a body of revolution under conditions of distributed air blowing". In ACTUAL PROBLEMS OF CONTINUUM MECHANICS: EXPERIMENT, THEORY, AND APPLICATIONS. AIP Publishing, 2023. http://dx.doi.org/10.1063/5.0132325.
Testo completo
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Tadjfar, M., Saman Kasmaiee e S. Noori. "Continuous Blowing Jet Flow Control Optimization in Dynamic Stall of NACA0012 Airfoil". In ASME 2020 Fluids Engineering Division Summer Meeting collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fedsm2020-20149.
Testo completoAbstract (sommario):
Abstract Use of active flow control techniques has become important in flow separation control. Continuous blowing jet is one of the most effective methods that can be used to improve aerodynamic performance of an airfoil. In the present work, different operational parameters of a continuous blowing jet were optimized to improve the aerodynamic performance of an oscillating NACA0012 airfoil. The airfoil underwent a sinusoidal motion about its quarter-chord between −5 and 25 degrees at the Reynolds number of 1.35 × 105. Unsteady Navier-Stokes equations were solved with k-ω SST turbulence model. Due to the time-consuming nature of large number of numerical simulations required during the optimization process, two neural networks were employed to reduce the number of simulations required. The optimization was carried out with the use of a genetic algorithm. The objective function was defined as the lift-to-drag ratio. In these networks, the relationship between the jet operational characteristics and the aerodynamic coefficients were trained. The jet operational parameters that were considered in this study, included jet location (at 1–60 percent of chord length), jet-opening length (0.05 to 0.3 percent of chord length), blowing jet velocity magnitude (0 to 5U∞), and blowing jet incident angle (0 to 180 degrees). Obtained results indicated that jet-opening length and blowing velocity magnitude have a greater effect on the aerodynamic performance when reached their upper values. Concerning the jet location, it was observed that the best jet location was about 2 to 5 percent of the chord Jet angle (θ) was found to results in the best performance when oriented at range 55 to 70 angle. Results indicated a significant improvement of the aerodynamic performance at the optimum blowing jet configuration.
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Ou, Shichuan, e Richard B. Rivir. "Shaped-Hole Film Cooling With Pulsed Secondary Flow". In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90272.
Testo completoAbstract (sommario):
The effects of the coolant jet pulsing frequency (PF), duty cycle (DC), and hole shape geometry on heat transfer coefficient and film effectiveness were investigated with a film hole located on a semicircular leading edge test model with an afterbody. Cylindrical and diffusion-shaped holes located at 21.5° from the stagnation line were investigated. An infrared thermography technique with a single transient test was used to determine both the heat transfer coefficient and film effectiveness. Spanwise averaged heat transfer coefficient and film effectiveness were computed from the local values for all test conditions under the same Reynolds number (Re) of 60,000 and density ratio (DR) of 1.11. A dimensionless Frossling number (Fr) was used to represent the heat transfer coefficient. The effects of duty cycles of 50%, 75%, and 100% (continuous coolant) on film effectiveness and heat transfer coefficient were investigated at coolant jet pulsing frequencies of 5 Hertz (Hz) and 10 Hertz. The duty cycle and pulsing frequency were controlled by the opening and closing time settings of two synchronized pulsed valves. The blowing parameters investigated included continuous coolant at the blowing ratios (M) of 0.75, 1.00, 1.50 and 2.00. The subsequent pulsed cases for a combination of pulsing frequency and duty cycle were varied from the corresponding continuous case without changing the coolant flow rate (or blowing ratio) setting for a total of 40 cases for the shaped and cylindrical film holes. The shaped hole provides higher local film effectiveness values than the classical cylindrical hole when coolant flow is steady at M = 1.00. The higher local film effectiveness for the shaped hole was also observed for pulsed cases at M = 1.50 (Meff = 1.25) and M = 2.00 (Meff = 1.07) due to wider film spreading or coverage. The pulsed coolant cases provide higher spanwise averaged film effectiveness than the continuous coolant at M = 1.50 for both hole geometries. In contrast to the film effectiveness, the spanwise averaged Frossling numbers of pulsed coolant are lower compared to the continuous coolant for both hole shapes at the same blowing ratio. Combining the effects of heat transfer coefficient and film effectiveness, one can compute a relative heat load ratio to evaluate the performance of the film cooling. The pulsed coolant cases in general perform better than continuous coolant. The shaped hole geometry provides better film cooling performance than the cylindrical hole geometry for all blowing ratios including the continuous and the pulsed coolant cases studied.
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Hassan, O., e I. Hassan. "Experimental Flow Field Investigations Downstream a Film Cooling Scheme Over a Flat Plate Using the PIV Technique". In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65650.
Testo completoAbstract (sommario):
This paper presents experimental investigations of the flow field characteristics downstream a Scaled-Up Micro-Tangential Jet (SUMTJ) film cooling scheme using the Particle Image Velocimetry (PIV) technique over a flat plate. The SUMTJ scheme is a shaped scheme designed so that the secondary jet is supplied tangentially to the surface. The scheme combines the thermal benefits of tangential injection and the enhanced material strength of discrete holes schemes, compared with continuous slot schemes. The flow field characteristics downstream one row of holes were investigated at three blowing ratios, 0.5, 1.0 and 1.5, calculated based on the scheme exit area. A density ratio of unity, a Reynolds Number of 1.16E+5 and an average turbulence intensity of 8%, were used throughout the investigations. The performance of the SUMTJ scheme was compared to that of the circular hole scheme, based line case, at the same test conditions and blowing ratios. From the investigations, it was noticeable that the SUMTJ scheme jet stays attached to the surface for long downstream distances at all investigated blowing ratios. Moreover, the lateral expansion angles of the scheme help perform a continuous film from adjacent jets close to the schemes exits; however, they have bad impact on the uniformity of the film thickness in the lateral direction. The vorticity strength downstream the SUMTJ scheme in the y-z plane was much less than the vorticity strength downstream the circular scheme at all blowing ratios. However, the vorticity behavior in the shear layer between the secondary SUMTJ scheme jet and the mainstream was changing dramatically with blowing ratio. The latter is expected to have a significant impact on the film cooling performance enhancement with blowing ratio increase.
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Rao, I. J. "Simulation of the Film Blowing Process Using a Continuum Model for Crystallization in Polymers". In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1993.
Testo completoAbstract (sommario):
Abstract In this paper we simulate the film blowing process using a model developed to study crystallization in polymers (see Rao (1999), Rao and Rajagopal (2000b)). The framework was developed to generate mathematical models in a consistent manner that are capable of simulating the crystallization process in polymers. During crystallization the polymer transitions from a fluid like state to a solid like state. This transformation usually takes place while the polymer undergoes simultaneous cooling and deformation, as in film blowing. Specific models are generated by choosing forms for the internal energy, entropy and the rate of dissipation. The second law of thermodynamics along with the assumption of maximization of dissipation is used to determine constitutive forms for the stress tensor and the rate of crystallization. The polymer melt is modeled as a rate type viscoelastic fluid and the crystalline solid polymer is modeled as an anisotropic elastic solid. The mixture region, where in the material transitions from a melt to a semi-crystalline solid, is modeled as a mixture of a viscoelastic fluid and an elastic solid. The anisotropy of the crystalline phase and consequently that of the final solid depends on the deformation in the melt during crystallization, a fact that has been known for a long time and has been exploited in polymer processing. The film blowing process is simulated using a generalized Maxwell model for the melt and an anisotropic elastic solid for the crystalline phase. The results of the simulation agree qualitatively with experimental observations and the methodology described provides a framework in which the film blowing problem can be analyzed.
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Shalash, Karim M., Lamyaa A. El-Gabry e Mohamed M. Abo El-Azm. "Investigation of a Novel Discrete Slot Film Cooling Scheme". In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-26019.
Testo completoAbstract (sommario):
The future of the gas turbine industry is strongly relying on the development of new efficient cooling schemes. Film cooling is one popular and reliable cooling technique, one way to increase the film cooling effectiveness is through the use of shaped holes. In this paper two proposed shaped holes are being studied and compared thoroughly against the conventional round hole film cooling. The two proposed holes are based on the theoretically perfect continuous slot film cooling, however, these slots are not continuous, and preserves the solid surface to the total blade surface ratio. The first design to be studied is the Rectangular Divergent Slot, and the second is the Aeroslot, which is a discrete aerodynamically shaped slot; both designs showed an increase in the centerline film cooling effectiveness when compared to the conventional round holes. The Aeroslot showed a large increase in film cooling effectiveness for the same blowing ratio, and mass flow rate of coolant, when compared to the other shapes. A sensitivity study of the blowing ratio to the centerline film cooling effectiveness is carried out for several blowing ratios, covering different jet in cross flow behaviors, fully attached jet, and detached-reattached jet.
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Coulthard, Sarah M., Ralph J. Volino e Karen A. Flack. "Effect of Jet Pulsing on Film Cooling: Part 2 — Heat Transfer Results". In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-91274.
Testo completoAbstract (sommario):
Pulsed film cooling was studied experimentally to determine its effect on film cooling effectiveness and heat transfer. The film cooling jets were pulsed using solenoid valves in the supply air line. Cases with a single row of cylindrical film cooling holes inclined at 35 degrees to the surface of a flat plate were considered at blowing ratios of 0.25, 0.5, 1.0, and 1.5 for a variety of pulsing frequencies and duty cycles. Temperature measurements were made using an infrared camera and thermocouples. The plate was equipped with constant flux surface heaters, and data were acquired for each flow condition with the plate both heated and unheated. The local film cooling effectiveness, Stanton numbers, and heat flux ratios were calculated and compared to baseline cases with continuous blowing and no blowing. Stanton number signatures on the surface provided evidence of flow structures including horseshoe vortices wrapping around the film cooling jets and vortices within the jets. Pulsing tends to increase Stanton numbers, and the effect tends to increase with pulsing frequency and duty cycle. Some exceptions were observed, however, at the highest frequencies tested. Overall heat flux ratios also show that pulsing tends to have a detrimental effect with some exceptions at the highest frequencies. The best overall film cooling was achieved with continuous jets and a blowing ratio of 0.5. The present results may prove useful for understanding film cooling behavior in engines, where mainflow unsteadiness causes film cooling jet pulsation.
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Coulthard, Sarah M., Ralph J. Volino e Karen A. Flack. "Effect of Jet Pulsing on Film Cooling: Part 1— Effectiveness and Flowfield Temperature Results". In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-91273.
Testo completoAbstract (sommario):
Pulsed film cooling was studied experimentally to determine its effect on film cooling effectiveness. The film cooling jets were pulsed using solenoid valves in the supply air line. Cases with a single row of cylindrical film cooling holes inclined at 35 degrees to the surface of a flat plate were considered at blowing ratios of 0.25, 0.5, 1.0, and 1.5 for a variety of pulsing frequencies and duty cycles. Temperature measurements were made using an infrared camera, thermocouples, and cold wire anemometry. Hot wire anemometry was used for velocity measurements. The local film cooling effectiveness was calculated based on the measured temperatures and the results were compared to baseline cases with continuous blowing. Phase locked flow temperature fields were determined from cold wire surveys. Pulsing at high frequencies helped to improve film cooling effectiveness in some cases by reducing overall jet liftoff. At lower frequencies, pulsing tended to have the opposite effect. With the present geometry and a steady mainflow, pulsing did not provide an overall benefit. The highest overall effectiveness was achieved with continuous jets and a blowing ratio of 0.5. The present results may prove useful for understanding film cooling behavior in engines, where mainflow unsteadiness causes film cooling jet pulsation.
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Asgari, Ehsan, e Mehran Tadjfar. "Comparison of Two Active Flow Control Mechanisms of Pure Blowing and Pure Suction on a Pitching NACA0012 Airfoil at Reynolds Number of 1 × 106". In ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fedsm2018-83463.
Testo completoAbstract (sommario):
In this study, we have applied and compared two active flow control (AFC) mechanisms on a pitching NACA0012 airfoil at Reynolds number of 1 × 106 using 2-D computational fluid dynamics (CFD). These mechanisms are continuous blowing and suction which are applied separately on the airfoil which pitches around its quarter-chord in a sinusoidal motion. The location for suction and blowing was determined in our previous study based on the formation of a counter clock-wise vortex near the leading-edge. In our current study, we have compared the effectiveness of pure blowing and pure suction in suppressing the dynamic stall vortex (DSV) which is the main contributor to the drag increase, particularly near the maximum angle of attack (AOA) and in early downstroke motion. The blowing/suction slot is considered as a dent on the airfoil surface which enables the AFC to perform in a tangential manner. This configuration would allow blowing jet to penetrate further downstream and was shown to be more effective compared to a cross-flow orientation. We have compared the two aforementioned mechanisms in terms of hysteresis loops of lift and drag coefficients and have demonstrated the dynamics of flow in controlled and uncontrolled situations.