Letteratura scientifica selezionata sul tema "Textural atomization"

Abstract A slurry electrothermal atomic absorption spectrometric technique was used to determine Ni and Cr in wheat flour and its by-products. Slurries (3%, w/v) were prepared in a mixture of 15% HNO3–10% H2O2 as suspended medium. Differences in Ni and Cr contents due to origin and texture of the wheat and to the effects of the milling process were studied. Ni and Cr levels were more markedly influenced by the geographical origin of the wheat than by its texture. Both metals were related to the amount of bran present in each milled fraction and varied over the ranges of 212–298 ng/g (Ni) and 34–85 ng/g (Cr) in flours (with minimal bran contents); 297–460 ng/g (Ni) and 67–118 ng/g (Cr) in shorts; and 424–723 ng/g (Ni) and 106–165 ng/g (Cr) in brans. The Ni and Cr contents were not significantly affected by the technological processes typically performed in a flour-producing factory.

In recent years there has been an exponential multiplication of media content, platforms and uses. After contextualizing the decline of the great theoretical currents of communication and exposing the linguistic bias of semiotics, this article proposes a review and characterization of the referential instruments and methodologies for the analysis of textual, multimodal and transmedia objects, with special emphasis on those of a connected digital nature. For this purpose, an integrative review of 75 documents that address the issue is carried out, leaving the final sample composed of the 25 most relevant for the purposes of the research. The epistemological-instrumental route goes from the Structural Analysis of the Story to Computer Vision, passing through Digital Ethnography and Multimodal Discourse Analysis. The conclusions include a sketch of an analysis instrument that synthesizes the study carried out, previously revealing the axiom put forward by several authors that there is no single invariable method for the study of this type of objects. The tendency, on the contrary, points to the atomization of research on specific aspects, rather than to a search for the generalization of results and the consolidation of theoretical bodies and universalizable techniques. It is also noted that quantitative turn and algorithmic programming for the study of digital objects open up a new analytical dimension with transhuman capabilities that is still far from being accessible to the international scientific community.

BACKGROUND Bronchiolitis is a common lower respiratory tract infection in infants and young children. Severe cases may be accompanied by obvious dyspnea and oxygen saturation decline. AIM To summarize the clinical features, standard diagnosis, and treatment of bronchiolitis. METHODS This is a retrospective analysis of 114 pediatric patients (74 males, 40 females) who were first diagnosed as having bronchioles at the Department of Pediatrics of Tongling Maternal and Child Health Hospital from January 2019 to December 2019. The clinical features, imaging features, treatment, and other clinical data were recorded and analyzed. RESULTS The age of onset of the disease was mainly from 1 mo to 6 mo (75.4%), and the time to hospital visit was mostly from the 2nd day to the 4th day of the course of the disease (75.4%). Lung imaging examination showed increase in lung texture, fuzzy (93.8%). The main treatment was atomization therapy: Budesonide combined with terbutaline (45.6%) and budesonide combined with salbutamol (38.5%). The average hospitalization time was 7.1 ± 2.4 d, and the overall cure rate was 94.7%. In patients without bacterial infection, the use of antibiotics significantly prolonged the length of hospital stay (7.8 ± 2.5 d vs 5.7 ± 1.8 d) and improved the cure rate (98.3% vs 87.9%, P < 0.05). CONCLUSION Infants with bronchiolitis are mainly male and tend to have a good prognosis. However, the unneeded use of antibiotics may prolong the length of hospital stay significantly, which imposes the burden both on the patients and hospital system.

В статье взаимно соотносятся тренд на «цифровизацию» человека и тенденция к атомизации городского пространства. Показано, что фрагментация современного человека и его практик аналогична дроблению городской среды. Излагается концепция визуального каркаса (текстуры) городского пространства, а также обосновывается неоднородность этого каркаса. Исследуются различные подходы к определению содержания, роли и количества элементов городской среды, или паттернов городского пространства, аргументируется смысловой и визуальный характер этих элементов. Демонстрируется отличие урбанистического паттерна от архитектурного, градостроительного и дизайнерского. Показана связь городской текстуры с индивидуальным обликом города. Исследованы качества и функции визуальных паттернов городской среды. Обоснован тезис о том, что единство городской среды удерживается благодаря взаимной открытости ключевых паттернов, а деградация городского пространства вызвана как нарушением целостности паттернов, так и их взаимной изоляцией. Паттерны как ключевые узлы визуально-пространственной среды представлены как взаимосвязанные локализованные социокультурные процессы, направленные на формирование элементов уникального облика города, то есть функционируют в качестве согласованных способов построения локальной идентичности. This article correlates the trend towards the “digitalization” of a person and the trend towards the atomization of urban space. It shows that the fragmentation of modern man and his practices is similar to the fragmentation of the urban environment. The concept of the visual frame (texture) of the urban space is presented, and the heterogeneity of this frame is substantiated. Various approaches to determining the content, role and number of elements of the urban environment, or patterns of urban space are explored; the semantic and visual nature of these elements is argued. The difference between the urban pattern and the architectural, urban planning, and design patterns is demonstrated. The connection between the urban texture and the individual appearance of the city is shown. The qualities and functions of the visual patterns of the urban environment are investigated. The thesis is substantiated that the unity of the urban environment is maintained due to the mutual openness of the key patterns, and the degradation of the urban space is caused both by the violation of the integrity of the patterns and their mutual isolation. Patterns as key nodes of the visual-spatial environment are presented as interrelated localized socio-cultural processes aimed at forming elements of the unique image of the city, that is, they function as coordinated ways of building a local identity.

Shape memory alloys (SMAs) are functional materials with a wide range of applications, from the aerospace sector to the biomedical field. Nowadays, there is a worldwide interest in developing SMAs through powder metallurgy like additive manufacturing (AM), which allows innovative building processes. However, producing SMAs using AM techniques is particularly challenging because of the microstructure required to obtain optimal functional properties. This aspect is critical in the case of Cu–Al–based SMAs, due to their high elastic anisotropy, making them brittle in polycrystalline form. In this work, we approached the processing of a Cu–Al–Ni SMA following a specific powder metallurgy route: gas atomization of a pre-alloyed melt; compaction of the atomized powders through hot isostatic pressing; and a final hot rolling plus thermal treatments. Then, the microstructure of the material was characterized by electron microscopy showing a specific [001] texture in the rolling direction that improved the functional behavior. The successive processing steps produce an increase of about 40 °C in the martensitic transformation temperatures, which can be well controlled and reproduced through the developed methodology. The thermomechanical functional properties of superelasticity and shape memory were evaluated on the final SMA. Outstanding, fully recoverable superelastic behavior of 4.5% in tension, as well as a ±5% full shape memory recovery in bending, were reported for many cycles. These experiments demonstrate the enhanced mechanical and functional properties obtained in polycrystalline Cu–Al–Ni SMAs by powder metallurgy. The present results pave the road for producing this kind of SMA with the new AM technologies, which always produce polycrystalline components and can improve their processes taking the powder metallurgy SMA, here produced, as reference material.

We live in a dodecahedron-structured cybernetic enmeshment of technology running through an extension of media convergence. In this context, the psychic fragmentation of a postmodern aesthetic is radically splintered and spreadeagled. The reflexivity praxis, embedded in a multisensory milieu navigating strange peregrinations (from modernity to postmodernity to post-post modernity), is tearing apart the current fabric, particularly through cinematic endeavors. Therefore, cinema hyphenates the piquant postmodernist aesthetics by orchestrating fragmentation, hyperkinetic synergy, anachronistic mode, pastiche, meta narratives, beats of simulacrum, and the dementia praecox of mutagenicity, to name a few. Films like Everything, Everywhere, All at Once (2022), directed by Daniel Kwan and Daniel Scheinert, encapsulate the current vertiginous reality through a metaverse of careening camera movement, frenetic editing, and the pulverization of the fractured self. A new neologism called “transgene” gets illustrated in the film, wherein multiple genre textures (science fiction, comic book aesthetic, melodrama, comedy, action, and an LGBTQ troupe) are indicated through singular sequences or even images in the film. This film clearly obfuscates the clarity of genre iconicity and exhibits a continuum of energy (flowing), but an interesting embodiment of the young girl concept through the character of Jobu Tupaki provides us with a structure in which postmodernism, transgene, and the young girl get encapsulated. The nihilistic and sassy daughter of Evelyn Wang has been fractured across realities of the metaverse, which renders her a powerful universal being bent on causing chaos and destruction. I shall attempt to outline the major configurations and reconceptualizations of several cinematic genres while foregrounding the plane of reality in which postmodernist cinema transforms into a trans-genre or rather undergoes a metamorphosis into a trans-genre. Additionally, it explores the phenomenon of a young girl functioning as a sublime and spectral obsequiousness amalgamated into the infrastructure of postmodernism, resulting in the atomization of trans-genres showcasing everything, everywhere, all at once. Furthermore, the confluence of these genre aesthetics prepares a bouillabaisse that embodies several configurations of young girls or the becoming of young girls (by all genders and ages) through an apocalyptic dread, permeable brain leaks, and a genre mix.

Le développement des moteurs-fusées destinés à équiper les futurs lanceurs nécessite une meilleure compréhension des phénomènes physiques complexes qui régissent leur fonctionnement. Dans le cas des moteurs-fusées à ergols liquides, la demande croissante pour des moteurs pouvant être rallumés de manière fiable dans l'espace impose une profonde compréhension des phases transitoires, telles que le démarrage et l'arrêt. Ces phases transitoires incluent généralement des régimes d'injection sous-critiques. L'oxygène est injecté à l'état liquide dans la chambre de combustion et subit une série de mécanismes : atomisation du jet dense, fragmentation des ligaments liquides, évaporation des gouttelettes et combustion turbulente. Dans ces conditions, le processus de combustion est principalement gouverné par l'atomisation de l'oxygène liquide, qui doit être reproduite avec précision par simulation afin de mieux comprendre son rôle dans l'apparition des instabilités de combustion.Avant d'utiliser la simulation comme un outil autonome pour étudier le processus d'atomisation, il est nécessaire d'assurer son niveau de précision. Cela nécessite de mener des campagnes d'essais expérimentaux sur des bancs d'essais capables de reproduire des conditions représentatives de moteurs-fusées, tels que le banc d'essai MASCOTTE à l’ONERA ou le banc d’essai MARACA au CORIA. L’objectif de ces études est de caractériser le processus d’atomisation et de fournir des données expérimentales qui peuvent être utilisées pour développer et valider des modèles numériques.L'étude expérimentale de l'atomisation primaire de l'oxygène liquide repose en particulier sur des techniques de visualisation des écoulements, qui permettent de représenter les structures liquides impliquées dans le processus. Le processus d’atomisation primaire observé dans les moteurs-fusées à ergols liquides peut être catégorisé comme texturel ou structurel, selon l’échelle à laquelle se produit l’atomisation. Les processus d’atomisation texturelle se caractérisent par le détachement de fins ligaments du jet, tandis que l’atomisation structurelle est liée à la rupture du volume liquide principal. Les visualisations issues de campagnes d’essais expérimentaux révèlent des écoulements diphasiques très complexes impliquant des systèmes liquides texturaux difficiles à caractériser en raison de leur large gamme d’échelles spatiales et temporelles. À ce jour, aucune technique n’est disponible pour décrire quantitativement les ligaments liquides impliqués dans ces processus d’atomisation texturelle observés expérimentalement.Dans cette thèse, une méthodologie est développée pour caractériser les processus d’atomisation primaire texturelle observés dans des conditions d’écoulement diphasique représentatives de celles rencontrées dans les moteurs-fusées à ergols liquides. Basée sur une méthode multi-échelle développée au CORIA, cette analyse fournit une caractérisation quantitative de la taille, de la forme et du nombre des structures liquides texturelles impliquées dans le processus d’atomisation texturelle sur toute sa gamme d’échelles spatiales. Cette caractérisation fournit des données pour le développement de modèles numériques d’atomisation primaire. En outre, l’application de cette méthodologie à des systèmes liquides décrits par des visualisations extraites de simulations numériques permet de valider les résultats de simulation en termes de leur reproduction des structures liquides participant au processus d’atomisation texturelle
The development of rocket engines to equip future launchers requires a better understanding of the complex physical phenomena that govern their operation. In the case of liquid-propelled rocket engines, the growing demand for engines that can be reliably reignited in space means that the transient phases such as start-up and shutdown must be better understood. These transient phases usually include subcritical injection regimes. Oxygen is injected in liquid state into the combustion chamber and undergoes a series of mechanisms: dense jet atomization, fragmentation of liquid ligaments, droplet evaporation, and turbulent combustion. Under these conditions, the combustion process is mainly driven by the atomization of the liquid oxygen, which must be accurately reproduced by simulation to better understand its role in the onset of combustion instabilities. Before using simulation as an autonomous tool to study the atomization process, it is necessary to ensure its level of accuracy. This requires conducting experimental test campaigns on test benches capable of reproducing conditions representative of rocket engines, such as the MASCOTTE test-bench at ONERA or the MARACA test-bench at CORIA. The goal of these studies is to characterize the atomization process and provide experimental data that can be used to develop and validate numerical models. The experimental study of primary atomization of liquid oxygen, in particular, relies on flow visualization techniques that depict the liquid structures involved in the process. The primary atomization process observed in liquid rocket engines can be categorized as textural or structural, depending on the scale at which the atomization takes place. Textural atomization processes are characterized by thin ligaments being peeled from the jet, while structural atomization is related with the breakup of the liquid bulk. Visualizations resulting from experimental test campaigns show very complex two-phase flows involving textural liquid systems that are difficult to characterize due to the wide range of spatial and temporal scales involved. To this day, no techniques are available to describe quantitatively the liquid ligaments involved in the textural atomization processes observed experimentally. In this thesis, a methodology is developed to characterize the textural primary atomization processes observed in the two-phase-flow conditions representative of those encountered in liquid rocket engines. Based on a multi-scale method developed at CORIA, this analysis provides a quantitative characterization of the size, shape and number of the textural liquid structures involved in the textural atomization process in its entire spatial scale range. This characterization provides information for the development of numerical primary atomization models. Additionally, the application of the methodology to liquid systems depicted by visualizations extracted from numerical simulations allow to validate the simulation results in terms of the correct reproduction of the liquid structures that participate in the textural atomization process

<div class="section abstract"><div class="htmlview paragraph">Diesel engines contain Nitrogen oxides (NOx) in exhaust gases, and is considered to be problematic in view of the environment. For worldwide NOx emission control, Selective catalytic reduction (SCR) dosing systems are widely used in aftertreatment systems. A mixer of the urea aqueous solution is placed between the injector and SCR catalysts and is used to provide good ammonia uniformity in SCR catalysts. It is very important to mix and evaporate the urea aqueous solution at short-distance using the optimum the mixer blade geometry. In this paper, the collision behavior of droplets into textured mixer surface materials are investigated by visualization experiment by backlight method. Then, several surface texture types were proposed as a means to improve the atomization performance of droplets by the mixer. In order to verify the performance of droplet atomization by the textures, a visualization experiment of droplet behavior was conducted using a simple experimental device including high-speed camera. Furthermore, the droplet diameter distribution before and after collision was calculated using the visualization results. Various conditions of droplet diameters were measured and the vaporization performances of the surface textures were studied. According to the results, 30 micron of pitch texture demonstrated good micronizing and evaporating of the droplets. This time, our study has established new visualization experiment methods for the aftertreatment systems, especially micro-scale of SCR dosing systems. It was found that improvement of the vaporization efficiency by surface texturing on the mixer or exhaust pipes.</div></div>

Abstract Interaction of a droplet on a heated substrate is a subject of extensive research due to its application in spray cooling of surfaces, thermal management of micro-scale devices, water harvesting etc. Depending on the surface temperature the droplet shows nucleate, transition boiling and Leidenfrost state. The presence of surface textures gives rise to various hydrodynamic outcomes such as droplet atomization, interfacial oscillations, and lift off. When a drop is deposited on a textured surface, it typically exists in two states called Cassie-Baxter and Wenzel depending on the substrate wettability and liquid-solid contact area. In the present work we explore a unique lift off mechanism at temperature range of (140–170°C) attributed to the excessive vapor force generated due to droplet impalement into the gap between the textures followed by evaporation of the imbibed liquid. The presence of microtextures (solid fraction) offers flow resistance to the escaping vapor which leads to increase in vapor pressure underneath the drop. When the vapor force exceeds the pinning force and weight of the drop, an explosive lift off occurs. We develop a force-based model to estimate the droplet volume corresponding to lift off on substrates with different morphologies and temperatures.

Abstract Thermal plasma spraying is a suitable technique for hydroxyapatite [HA, Ca10(P04)6(OH)2] coating preparation. Suspension Plasma Spraying (SPS) is a newly developed process based on a suspension of fine (&lt;10 μm) or even ultrafine (&lt;100 μm) powders, axially fed into the RF plasma through an atomization probe. The atomization of the suspension results in microdroplets (20 μm in size). They are flash dried, melted and finally impacted onto the substrate to solidify and build the coating. The aqueous suspension of HA is chemically synthesized. Our experiments included variations of the plasma gas composition (Ar/O2, Ar/H2), the plasma deposition reactor pressure. Characterizations techniques (e.g. X-ray diffraction, scanning electron microscope and transmission electron microscope) were applied to resultant SPS HA coatings which possessed good crystallinity and about 3% weight α-TCP and lime. The texture examination has shown that preferential crystal orientation followed the (001) Miller's plane family. SPS by RF induction plasma has proved to be a reliable process for the production of thick (200 μm) HA coatings with high deposition rate (&gt;150 μm/min).

The development of spherical Ti/Nb/Ta alloy powders with compositions Ti-xNb-6Ta (x = 20, 27, 35 wt%) by electrode induction melting gas atomization (EIGA) and their processing by laser beam powder bed fusion (PBF-LB/M) are reported. Microstructure investigations by X-ray diffraction and scanning electron microscopy including energy dispersive X-ray spectroscopy and electron backscatter diffraction reveal a significant impact of the composition on the structural properties, i.e., phase evolution and texture, and the possibility for a direct microstructure design. Ti-rich alloys preferably solidify in the orthorhombic α’’-phase, whereas in Nb/Ta-rich alloys the body-centered cubic (bcc) β-phase is observed. The alloys possess a very broad processing window and can be printed to full density over a wide range of printing parameters. Additively manufactured Ti-27Nb-6Ta shows a unique behavior, since strength and elongation at failure strongly depend on the printing parameters applied. The underlying microstructural mechanisms, i.e., the influence of the laser energy on texture effects and phase formation, are discussed.