Literatura académica sobre el tema "Natal Field Force"
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Artículos de revistas sobre el tema "Natal Field Force"
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Siregar, Muhammad Yusuf, Risdalina Risdalina y Sriono Sriono. "The Position of Women's Heritage Rights in the Context of Islamic Heritage in Indigenous Mandailing in Sipirok District, Tapanuli Selatan Regency". Budapest International Research and Critics Institute (BIRCI-Journal) : Humanities and Social Sciences 3, n.º 1 (12 de febrero de 2020): 531–39. http://dx.doi.org/10.33258/birci.v3i1.804.
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This study aims to analyze the legal aspects of the Position of Inheritance Rights of Girls in the Context of Islamic Inheritance in Indigenous Mandailing in Sipirok District, South Tapanuli Regency. This research is empirical normative namely research by looking at existing conditions in the field by linking the source of Islamic Law and the legal source of Regulations in force in the Republic of Indonesia. The benefits to be received from the results of this study are to determine the Position of Inheritance of Girls in the Context of Islamic Law and Regulations in Indonesia and the Position of Inheritance of Girls in the Context of Islamic Inheritance in Mandailing Customs in Sipirok District, South Tapanuli Regency, the results of the study stated that In Islamic Inheritance Law strongly recognizes the position of the daughter in receiving inheritance with a strong legal basis in accordance with the al-Qur’an. In Islamic Inheritance Laws, a daughter has a position as Nasabiyah's heir so that she has the right to receive inheritance. In the Mandailing customary inheritance law in Sipirok Mandailing Natal, the position of a daughter is considered as an heir when a male heir is found, but if the girl is a mere woman, the woman is not entitled to inheritance from her parents. The distribution of inheritance in the Mandailing Inheritance law in Sipirok Mandailing Natal uses local customary law, as a basis for the distribution of inheritance which is still being realized in the Community.
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Hyslop, Jonathan. "The world voyage of James Keir Hardie: Indian nationalism, Zulu insurgency and the British labour diaspora 1907–1908". Journal of Global History 1, n.º 3 (noviembre de 2006): 343–62. http://dx.doi.org/10.1017/s1740022806003032.
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In 1907–1908, the British labour leader, James Keir Hardie, made a round-the-world tour, which included visits to India, Australasia and southern Africa. The support for Indian nationalism which he expressed precipitated a major international political controversy, in the course of which Hardie came under severe attack from the Right, both in Britain and in her colonies. In southern Africa, the issue, combined with Hardie’s earlier criticism of the repression of the 1906 Bambatha rising in Natal, sparked rioting against Hardie by British settlers during his visit. This article seeks to show how Hardie’s voyage illuminates the imperial politics of its moment. Hardie’s journey demonstrates how politics in the British colonies of his era took place not within local political boundaries, but in a single field which covered both metropolis and colonies. The article is a case study which helps to illustrate and develop an argument that the white working classes in the pre-First World War British Empire were not composed of nationally discrete entities, but were bound together into an imperial working class which developed a distinct common ideology, White Labourism, fusing elements of racism and xenophobia with worker militancy and anti-capitalism. The current paper refines this analysis of the politics of the imperial working class by situating it in relation to the rising force of Indian nationalism in the same period, and to the changes this development generated in the politics of the settler colonies and the imperial centre. In India, Hardie forged links with the dynamic new political mobilization that had followed on the crisis over the partition of Bengal. In doing so, he entered, as an ally, into the discursive struggle which Indian nationalists were waging for self-government. By taking a pro-Indian position he antagonized the British Right. Labourites in the white settlement colonies wanted to defend Hardie, as a representative figure of British labour, but were embarrassed by the fact that Hardie’s position on India went against the grain of White Labourist ideology. In southern Africa, local leaders of British labour did opt to defend Hardie. But they did so not only at the risk of alienating their members, but also at the price of being forced into direct confrontations with anti-Hardie groupings.
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Kumbla, Pallavi A., Ashley Q. Thorburn, Jorge I. de la Torre y René P. Myers. "Correction of Severe Frontal Bossing with Coronal Brow Lift and Osteoplastic Frontal Sinus Setback Aided by Virtual Surgical Planning: A Case Report". Craniomaxillofacial Trauma & Reconstruction Open 5 (1 de enero de 2020): 247275122097491. http://dx.doi.org/10.1177/2472751220974918.
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Objective: An 18 year old male with a hypoplastic midface, low anterior hairline, heavy brows and marked frontal bossing presented for evaluation. Laboratory evaluation for acromegaly was negative. He did have impairment of his bilateral visual fields as confirmed by visual field testing by ophthalmology. His nasal radix was also of particular concern to him as it formed a significantly depressed crease between his nasal bridge and his brow. He requested surgical correction of these deformities from both a functional and aesthetic standpoint. Methods: We performed thin-cut CT maxillofacial scanning with 3D reformats and submitted this for virtual surgical planning (VSP). We were able to create a template with which to remove the anterior table of the frontal sinus safely, confidently, and without the aid of a craniotomy. The operation was performed through a preexisting bicoronal incision. The anterior table of the frontal sinus was removed in one piece. His forehead and superior orbits were contoured with a burr. After contouring, the anterior table was fixated in a more recessed position. Nasal radix augmentation was also performed using bone grafting. A coronal brow lift was then performed. Results: The patient’s post-operative course was uneventful. He noted marked improvement in his superior visual fields. He had complete resolution of his nasal radix deformity and his frontal bossing. This was confirmed by thin-cut CT maxillofacial scanning postoperatively. His frontal branches were functionally intact and his hairline was raised to a more appropriate position. Conclusions: Virtual surgical planning allowed us to perform an osteoplastic forehead reduction safely and without older methods such as Caldwell x-rays with coin reference, transillumination, or the bayonet forcep technique. It also allowed us to avoid the use of surgical navigation which can be time consuming and cumbersome. This VSP-based access to the frontal sinus has applications in many aspects of reconstructive cranial surgery as well as aesthetic forehead reductions for patients that do not require a craniotomy.
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Makihara, Seiichiro, Mitsuhiro Okano, Tazuko Fujiwara, Yohei Noda, Takaya Higaki, Tomomi Miyateke, Kengo Kanai, Takenori Haruna, Shin Kariya y Kazunori Nishizaki. "Local Expression of Interleukin-17a is Correlated with Nasal Eosinophilia and Clinical Severity in Allergic Rhinitis". Allergy & Rhinology 5, n.º 1 (enero de 2014): ar.2014.5.0078. http://dx.doi.org/10.2500/ar.2014.5.0078.
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Interleukin (IL)-17A is a major cytokine produced by Th17 cells, which are associated with chronic inflammations. The local expression of IL-17A in allergic rhinitis (AR) remains to be characterized. We sought to determine the role of IL-17A expression in human inferior turbinate mucosa in the pathophysiology of AR. Inferior turbinate mucosa was sampled from medical treatment-resistant, surgery-required patients with perennial AR (PAR, n = 21), nonallergic rhinitis with eosinophilia syndrome (NARES, n = 7), and nonallergic hypertrophic rhinitis (HR, n = 13). IL-17A expression was determined with immunohistochemical staining. The mean number of IL-17A+ cells and eosinophils per field were counted. Total serum immunoglobulin E (IgE) levels, blood eosinophil count, and forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio were also examined in each patient. IL-17A was primarily expressed in infiltrating inflammatory cells. The number of IL-17A+ cells in nasal mucosa was significantly higher in the PAR group compared with HR (p = 0.002) and NARES (p = 0.021) groups. There was a significant and positive correlation between the number of IL-17A+ cells and total nasal symptom score (rho = 0.403; p = 0.011), especially sneezing score (rho = 0.471; p = 0.003). The number of IL-17A+ cells was significantly and positively correlated with the degree of eosinophil infiltration (rho = 0.623; p < 0.001), but not with total serum IgE levels (rho = 0.284; p = 0.098), blood eosinophil counts (rho = 0.302; p = 0.056), or FEV1/FVC ratio (rho = 0.092; p = 0.569). The present study provides evidence that IL-17A expression in the nasal mucosa is associated with the pathophysiology of AR, including disease severity and nasal eosinophilia.
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Lueck, Christian J., Emily Kane, David Ashton, Peter Mews, Kate Reid y Andrew J. Neely. "019 Correlation of visual field loss with mri findings in patients with pituitary tumours". Journal of Neurology, Neurosurgery & Psychiatry 89, n.º 6 (24 de mayo de 2018): A9.1—A9. http://dx.doi.org/10.1136/jnnp-2018-anzan.19.
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IntroductionThe exact mechanism that gives rise to bi-temporal hemianopia in chiasmal compression by pituitary tumours is currently unknown. One theory suggests that, because crossing fibres cross each other and therefore have less contact area, they experience greater stress from compressive forces than those experienced by uncrossed fibres (which have a larger contact area). Finite element modelling has been used has been used to investigate this in silico but the hypothesis needs testing in vivo. This study aimed to determine whether extrinsic chiasmal compression was associated with patterns of visual field loss which supported the ‘crossing hypothesis’ or not.MethodsSubjects with chiasmal compression secondary to pituitary tumours who also had clear visual field abnormalities were identified from the Canberra Hospital database. Visual fields were analysed to derive ‘temporality’ and ‘bi-temporality’ indices. MRI scans were analysed to determine the relative elevations of centre and peripheral portions of the optic chiasm and, in turn, the eccentricity of compression. Temporality indices were plotted against central chiasmal elevation, and both temporal and nasal hemi-field abnormalities were plotted against eccentricity.Results122 patients were identified but only 12 were suitable for analysis. Both temporality and bi-temporality indices were significantly correlated with central chiasmal elevation (p=0.004). Hemi-field studies demonstrated patterns of visual loss with increasing eccentricity that were more consistent with the ‘crossing hypothesis’ though the correlations failed to reach significance.ConclusionThis study provides tentative support for the ‘crossing hypothesis’. The information will be used to inform further finite element models of chiasmal compression. A larger, prospective study is warranted.
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Persson, Ann-Charlotte, Sabine Reinfeldt, Bo Håkansson, Cristina Rigato, Karl-Johan Fredén Jansson y Måns Eeg-Olofsson. "Three-Year Follow-Up with the Bone Conduction Implant". Audiology and Neurotology 25, n.º 5 (2020): 263–75. http://dx.doi.org/10.1159/000506588.
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Background: The bone conduction implant (BCI) is an active transcutaneous bone conduction device where the transducer has direct contact to the bone, and the skin is intact. Sixteen patients have been implanted with the BCI with a planned follow-up of 5 years. This study reports on hearing, quality of life, and objective measures up to 36 months of follow-up in 10 patients. Method: Repeated measures were performed at fitting and after 1, 3, 6, 12, and 36 months including sound field warble tone thresholds, speech recognition thresholds in quiet, speech recognition score in noise, and speech-to-noise thresholds for 50% correct words with adaptive noise. Three quality of life questionnaires were used to capture the benefit from the intervention, appreciation from different listening situations, and the ability to interact with other people when using the BCI. The results were compared to the unaided situation and a Ponto Pro Power on a soft band. The implant functionality was measured by nasal sound pressure, and the retention force from the audio processor against the skin was measured using a specially designed audio processor and a force gauge. Results: Audiometry and quality of life questionnaires using the BCI or the Ponto Pro Power on a soft band were significantly improved compared to the unaided situation and the results were statistically supported. There was generally no significant difference between the two devices. The nasal sound pressure remained stable over the study period and the force on the skin from the audio processor was 0.71 ± 0.22 N (mean ± 1 SD). Conclusion: The BCI improves the hearing ability for tones and speech perception in quiet and in noise for the indicated patients. The results are stable over a 3-year period, and the patients subjectively report a beneficial experience from using the BCI. The transducer performance and contact to the bone is unchanged over time, and the skin area under the audio processor remains without complications during the 3-year follow-up.
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Réthoré, Gildas, Cécile Boyer, Kouakou Kouadio, Amadou Toure, Julie Lesoeur, Boris Halgand, Fabienne Jordana, Jérôme Guicheux y Pierre Weiss. "Silanization of Chitosan and Hydrogel Preparation for Skeletal Tissue Engineering". Polymers 12, n.º 12 (27 de noviembre de 2020): 2823. http://dx.doi.org/10.3390/polym12122823.
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Tissue engineering is a multidisciplinary field that relies on the development of customized biomaterial to support cell growth, differentiation and matrix production. Toward that goal, we designed the grafting of silane groups onto the chitosan backbone (Si-chito) for the preparation of in situ setting hydrogels in association with silanized hydroxypropyl methylcellulose (Si-HPMC). Once functionalized, the chitosan was characterized, and the presence of silane groups and its ability to gel were demonstrated by rheology that strongly suggests the presence of silane groups. Throughout physicochemical investigations, the Si-HPMC hydrogels containing Si-chito were found to be stiffer with an injection force unmodified. The presence of chitosan within the hydrogel has demonstrated a higher adhesion of the hydrogel onto the surface of tissues. The results of cell viability assays indicated that there was no cytotoxicity of Si-chito hydrogels in 2D and 3D culture of human SW1353 cells and human adipose stromal cells, respectively. Moreover, Si-chito allows the transplantation of human nasal chondrocytes in the subcutis of nude mice while maintaining their viability and extracellular matrix secretory activity. To conclude, Si-chito mixed with Si-HPMC is an injectable, self-setting and cytocompatible hydrogel able to support the in vitro and in vivo viability and activity of hASC.
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Shahack-Gross, Ruth y Israel Finkelstein. "Settlement Oscillations in the Negev Highlands Revisited: The Impact of Microarchaeological Methods". Radiocarbon 57, n.º 2 (2015): 253–64. http://dx.doi.org/10.2458/azu_rc.57.18561.
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Microarchaeological methods, especially those focused on geoarchaeology and radiocarbon dating, have revolutionized the manner in which the Iron Age settlement peak in the Negev Highlands is interpreted. We review here results from field and laboratory studies conducted at two Iron Age sites (Atar Haroa and Nahal Boqer) compared to one Byzantine/Early Islamic site (Wadi el-Mustayer)—all located near Sede Boqer. We present our methodology, which is based on small-scale but detailed excavations, study of sediments, and identification of livestock dung remains and their utility as indicators of past subsistence practices. To this we add meticulous 14C dating, ceramic petrography, and identification of botanic and zoological remains. We conclude that subsistence during the Iron Age included tending livestock but did not include agriculture. We further propose that the long-distance trade of copper from the Arabah Valley under Egyptian auspices and possibly the trading of cinnamon, dates, and other Arabian/Indian commodities were the driving force in the initiation (and later decline) of the Iron Age settlement system. We hypothesize that the agricultural settlement peak during the Byzantine/Early Islamic period was also influenced by an imperial power from outside of the Negev and that large-scale agriculture was enabled due to the adoption of new agricultural techniques, including terracing of ephemeral streams along with water diversion systems and possibly water storage facilities such as advanced cisterns. Future studies are expected to shed additional light on the complexity of settlement oscillations in the Negev Highlands region in key periods such as the Early and Intermediate Bronze Ages.
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Be'eri, Eyal. "Yearning, Control, and Creativity: The Carnivorous Bird in Literature and Poetry". Moreshet Israel 19, n.º 1 (2021): 159–84. http://dx.doi.org/10.26351/mi/19-1/7.
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During my travels in India, I was captivated by the allure of the carnivorous Indian eagle. Inspired by that experience, this article seeks to examine various motifs associated with literary representations of birds of prey. The first section explores the motifs of physiological and androgynal bisexuality associated with these creatures, and the androgynous motif of them as expressed in the works of Jerzy Kosiński and Sarah Sheila. The work of Abraham Mapo, and William Shakespeare’s poem “The Phoenix and the Turtle,” are the basis of the next discussion about aspects of the experience of transitions between the different stages of life. By exploring the poetry of Shaul Tchernichovsky, Avraham Shlonsky, Natan Yonatan, and others, this section also studies the elements of aggression and control as symbolized by the spiritual soaring of a bird above the fields of reality. In its final section, the article discusses the wild bird as a noble expression of supreme creative inspiration, an encounter with the deity, and prophetic inspiration. Beyond the dynamics between bisexuality, the difficulties of transition, and noble certainty, the article finds that bisexual desire is often replaced by a desire to control the other, and these forces undergo a process of refinement and purification through the development of meaningful creative lives.
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ФЕДОРІВ, УЛЯНА. "РЕПРЕЗЕНТАЦІЯ ОБРАЗУ ГЕРОЯ-ВОЇНА В УКРАЇНСЬКІЙ СОЦРЕАЛІСТИЧНІЙ ЛІТЕРАТУРІ". Studia Ukrainica Posnaniensia 8, n.º 2 (31 de diciembre de 2020): 107–17. http://dx.doi.org/10.14746/sup.2020.8.2.08.
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The article is devoted to the research of socialist realism canon in Ukrainian literature. This canon is considered an artificially modeled power project in the sphere of culture and literature which aimed at creating a monostylistic system with clearly defined rules and recommended schemes, especially including thought-out characters understandable for the mass Soviet reader in order to monopolize power at all levels and to establish a new Soviet identity (“homo sovieticusˮ). The socialist realism canon is a complex and heterogeneous phenomenon. It imposed patterns for analysing and reflecting on reality in art and culture. From the 1930s, any texts following the authorities’ regulations acquired a typical structure, predictable and recognizable features that turned literature into a mass-produced uniform “artistic” product. The task of such a governmental experiment was both to transform the world, and to change the way reality was perceived. The aesthetized falsification of existence, the clear domination of everything “ideological” and “totalitarian” in the field of culture, shaping the socialist realistic theory as a process of politicizing artistic consciousness - these are the blocks that determined the formation and functioning of the socialist realism canon of Ukrainian literature. The publication reflects a new vision of the problem of the literary representation of the Soviet Pantheon of Heroes in the socialist realism texts, in particular novels by Natan Rybak, Yurii Zbanatskyi, Oles Honchar, Andrii Malyshko, Natalia Zabila etc. Basically, the idea is that in order to build a bright future the Soviet system needed a new man, so all the forces were thrown into the “newanthropological typeˮ. The article deals with the modeling role of the hero-warrior in the socialist realism text. This image was established in the mass consciousness by means of propaganda and agitation.
Libros sobre el tema "Natal Field Force"
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Aeronautical Systems Center (U.S.). Environmental Management Directorate. y Geological Survey (U.S.), eds. Development of a geodatabase and conceptual model of the hydrogeologic units beneath Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas. Austin, Tex: U.S. Dept. of the Interior, U.S. Geological Survey, 2004.
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Williams, M. D. Locations and monitoring well completion logs of wells surveyed by U.S. Geological Survey at Air Force Plant 4 and Naval Air Station, Joint Reserve Base, Carswell Field, Fort Worth area, Texas. Austin, Tex: U.S. Dept. of the Interior, U.S. Geological Survey, 1996.
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Garcia, Carmen A. Subsurface occurrence and potential source areas of chlorinated ethenes identified using concentrations and concentration ratios, Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas. Reston, Va: U.S. Geological Survey, 2005.
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Great Britain. War Office. General Staff., ed. The Russo-Japanese War: Reports from officers attached to the Japanese forces in the field. London: Ganesha Publishing, 2000.
Buscar texto completoCapítulos de libros sobre el tema "Natal Field Force"
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"The Natal Field Force". En The Transvaal Rebellion, 139–57. Routledge, 2014. http://dx.doi.org/10.4324/9781315835631-16.
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Forth, Aidan. "“A System Steadily Perfected”". En Barbed-Wire Imperialism. University of California Press, 2017. http://dx.doi.org/10.1525/california/9780520293960.003.0008.
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In an effort to reduce mortality rates from epidemic disease, the British government engaged in a campaign to reform the Anglo-Boer War concentration camps. Officials like Alfred Milner and Joseph Chamberlain actively mobilized imperial Britain’s long history of encampment and solicited expertise from the fields of metropolitan welfare and social investigation to appoint a women’s committee (led by Millicent Fawcett) to visit the camps and recommend reforms. Chamberlain also contacted the India Office and ultimately imported Colonels Samuel J. Thomson and James S. Wilkins, who had analogous inter-imperial experience managing plague and famine camps in India. Drawing from lessons synthesized in India, these “imperial careerists” introduced stricter discipline and new measures like barbed-wire quarantine wards and forced hospitalization, which ultimately reduced camp mortality. New camps in Cape Colony and Natal constructed by Wilkins and Thomson refined camp management to a state of perfection and helped vindicate concentration camps as a legitimate technology of imperial statecraft and emergency relief.
Actas de conferencias sobre el tema "Natal Field Force"
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Jiao, Guandong y Christopher D. Rahn. "Current Waveform Optimization for Low Noise Permanent Magnet Motors". En ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33058.
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During torque production, the varying magnetic fields inside an electric motor excite vibration that radiates acoustic noise. In consumer applications, this noise can influence the perceived product quality. Noises from propulsion and auxiliary electric motors on naval vessels create an acoustic signature that increases detectability. The dominant noise occurs at twice the electrical frequency (2E). For permanent magnet (PM) machines, the attraction between the rotor permanent magnets and the stator iron causes a radial force that varies sinusoidally around the stator. The stator coil currents generate a rotating magnetic field that produces rotor torque. This paper develops a new commutation strategy for PM machines that uses higher stator currents to minimize 2E noise by reducing radial force ripple without sacrificing torque. An analytical model is developed that predicts rotor torque and radial force ripple as functions of the stator currents. Based on this model, the phase currents are optimally commutated to maintain constant torque production and reduce force ripple. The optimal commutation is numerically investigated on a small PM motor using ANSYS FEA. The ANSYS results show a 30% reduction in force ripple at no load.
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Wanis, Sameh S. "Validation of Tailored Force Fields Concept for Use in Space-Based Construction". En SPACE TECH.& APPLIC.INT.FORUM-STAIF 2006: 10th Conf Thermophys Applic Microgravity; 23rd Symp Space Nucl Pwr & Propulsion; 4th Conf Human/Robotic Tech & Nat'l Vision for Space Explor.; 4th Symp Space Coloniz.; 3rd Symp on New Frontiers & Future Concepts. AIP, 2006. http://dx.doi.org/10.1063/1.2169299.
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Martins, Joao Alcino de Andrade. "Measurements in Circular Wave Tank With Active Generators". En ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-80013.
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This paper discusses some aspects of the new technology in testing tank for Naval and Ocean Engineering developed at NAOE-Osaka University, Japan, based on the concept of active wavemakers all around the tank perimeter [1]. Past and present measurements shown that the wave field is homogeneous with some restrictions and can keep irregular wave more than 50 wave periods. The experimental results for platform model diffraction force are good and agree with theory and also with early tests [7]. The analyses of wave and platform model force measurements prove the new wave tank concept precision, usefulness and reliability.
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Iliopoulos, Athanasios, John G. Michopoulos y John C. Hermanson. "Composite Material Testing Data Reduction to Adjust for the Systematic 6-DoF Testing Machine Aberrations". En ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-71119.
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This paper describes a data reduction methodology for eliminating the systematic aberrations introduced by the unwanted behavior of a multiaxial testing machine, into the massive amounts of experimental data collected from testing of composite material coupons. The machine in reference is a custom made 6-DoF system called NRL66.3 and developed at the NAval Research Laboratory, that consists of multiple sets of hexapod configurations essentially forming a recursive synthesis of multiple parallel mechanisms. Hexapod linkages, the grips, and other deformable parts of the machine absorb energy. This is manifested in an either reversible or irreversible manner, thus introducing a parasitic behavior that is undesirable from the perspective of our ultimate goal of the material constitutive characterization. The data reduction focuses both on the kinematic (pose of the grip) and the reaction (forces and moments) that are critical input quantities of the material characterization process. The kinematic response is reduced by exploitation of the kinematics of the dots used for full field measurements. A correction transformation is identified by solving an inverse problem that minimizes the known displacements at the grips as given by the full field measurements and those given by the machine’s displacement sensors. A Procrustes problem formalism was introduced to exploit a known material behavior tested by the testing machine. Consequently, a correction transformation was established and was applied on the load cell data of the machine in order to eliminate the spurious responses appearing in the force and moment data.
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Vaz, Guilherme, Serge Toxopeus y Samuel Holmes. "Calculation of Manoeuvring Forces on Submarines Using Two Viscous-Flow Solvers". En ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20373.
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Submersibles used for exploration, maintenance and naval warfare have to be both manoeuvrable and easy to control. Simulation of the trajectory for these vessels requires the accurate determination of the hydrodynamic forces and moments which are determined by model-testing, empirical methods or a combination of both. CFD can play a role here by permitting an easier and more accurate determination of these loads. In this paper we focus on the accurate prediction of the manoeuvring forces of free swimming streamlined submersibles (submarines) using CFD. We compare simulations of a standardised well-known submarine shape (DARPA SUBOFF) for two configurations, one bare hull (AFF-1) and one fully-appended hull (AFF-8), under different inflow angles. The viscous-flow solvers used are the finite volume solver ReFRESCO developed by MARIN, and the finite element commercial solver AcuSolve. Verification studies are performed and the numerical results are validated with the experimental data available in the literature. The influence of different turbulence models is investigated and results obtained with a RANS (Reynolds-Averaged-Navier-Stokes) approach are compared with the theoretically more realistic DDES (Delayed-Detached-Eddy-Simulation) results. The influence of the appendages on the forces and flow fields is also investigated and analysed. As a last example, results of a forced pitch motion including dynamic effects are presented.
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Ducoin, Antoine, Jacques-Andre´ Astolfi, Franc¸ois Deniset, Jean-Franc¸ois Sigrist y Vincent Soyer. "An Experimental and Numerical Investigation of Flow Over a Hydrofoil in Transient Regimes Based on Wall-Pressure Analysis". En ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61575.
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The present study is developed within the general framework of marine structure design of lifting bodies, operating in transient regimes. The study concerns the experimental and numerical investigations of time-space distribution of the wall pressure field on a NACA66 hydrofoil in forced ramping motion. The angle of incidence varies from 0° to 15° beyond stall. Experiments in a hydrodynamic tunnel and corresponding RANSE based code calculations are carried out for various pitching velocities. Transducers are located along the chord of the hydrofoil. The numerical approach is conducted in turbulent regime using recent laminar to turbulent transition model. Global coefficients are analyzed in order to quantify the transient effects. The comparison of calculated to measured local wall pressures on the suction side leads to the identification of the effect of pitching velocity on hydrodynamic loading. Moreover, the consequences of pressure fluctuations induced by the laminar to turbulent transition are highlighted. The evolutions of transition, laminar bubble and leading and trailing edge detachments are discussed in the context of naval applications.
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Kitazawa, Daisuke y Jing Yang. "Numerical Study on Circulation and Thermohaline Structures With Effects of Icing Event in the Caspian Sea". En ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20667.
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A hydrostatic and ice coupled model was developed to analyze circulation and thermohaline structures in the Caspian Sea. The northern part of the Caspian Sea freezes in the winter. Waters start icing in November and ices spread during December and January. The northern part of the Caspian Sea is covered by ices in severe winters. Ice-covered area is at its maximum during January and February, and then ices begin melting in March and disappear in April. The occurrence of ices must have significant effects on circulation and thermohaline structures as well as ecosystem in the northern Caspian Sea. In the present study, formation of ices is modeled assuming that ices do not move but spread and shrink on water surface. Under the ices, it is assumed that the exchange of momentum flux is impeded and the fluxes of heat and brine salt are given at sea-ice boundary. The ice model was coupled with a hydrostatic model based on MEC (Marine Environmental Committee) Ocean Model developed by the Japan Society of Naval Architect and Ocean Engineers. Numerical simulation was carried out for 20 years to achieve stable seasonal changes in current velocity, water temperature, and salinity. The fluxes of momentum, heat, and salt were estimated by using measurement data at 11 meteorological stations around the Caspian Sea. Inflow of Volga River was taken into account as representative of all the rivers which inflow into the Caspian Sea. Effects of icing event on circulation and thermohaline structures were discussed using the results of numerical simulation in the last year. As a result, the accuracy of predicting water temperature in the northern Caspian Sea was improved by taking the effects of icing event into account. Differences in density in the horizontal direction create several gyres with the effects of Coriolis force. The differences were caused by differences in heat capacity between coastal and open waters, differences in water temperature due to climate, and inflow of rivers in the northern Caspian Sea. The water current field in the Caspian Sea is formed by adding wind-driven current to the dominant density-driven current, which is based on horizontal differences in water temperature and salinity, and Coriolis force.
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Bonfiglio, Luca y Stefano Brizzolora. "A Numerical Investigation over the Cavitating Flow Regime of a 2D-Hydrofoil". En SNAME 13th International Conference on Fast Sea Transportation. SNAME, 2015. http://dx.doi.org/10.5957/fast-2015-041.
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The advances in sailing boat races have been greatly proven in the recent America’s Cup competition. Sailing boats have reached speeds above 40 knots with a simple concept: the wetted surface of the hull is minimized and the required displacement is obtained through a lifting force produced by submerged hydrofoils working at very high speeds. This is a well-known concept in naval architecture that has been exploited since the beginning of the 20th Century. Hydrofoils used in sailing boat races are yet not designed for cavitating flow, but major changes in the design will be needed in case speed increases above 50 knots. When highspeed crafts (including fast sailing boats) operate significantly above the planing threshold speed, the convenience of completely or partially supporting their weight by lifting hydrofoils is evident (Du Cane (1964)). A very low pressure field induced by high in flow speed triggers water vaporization at ambient temperature: cavitation cannot be avoided and foil shape has to be designed with the goal of maintaining a stable flow regime eventually com-promising the lift. When craft speed arise above 50 knots, the de-sign philosophy for the basic section of the lifting hydrofoil has to radically change and turn to super-cavitating hydrofoils (Auslaender [1962]) being the final goal addressed towards the delay and stabilization of the cavity shape over the hydrofoil surface. In super-cavitating regimes the suction surface of the hydrofoil is fully enveloped in the cavity which (typically) detaches at the leading edge of the foil and closes in the wake well aft the trailing edge. The pressure side of the hydrofoil is the only responsible for lift generation thus the main design target is represented by the shape of the foil surface. Several simplified theories assuming steady state potential flow (mentioned later in this introduction) were developed in the past to deal with this essential design problem.
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Dai, Charles M., Ronald W. Miller y A. Scott Percival. "Hydrodynamic Effects of Bilge Keels on the Hull Flow During Steady Turns". En ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79585.
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The hydrodynamic design of the bilge keels is important for the ship’s resistance and roll performance. It also affects the ship wake field at the propeller plane and can greatly influence the propulsor performances in terms of noise, efficiency and cavitation. The objective of this work is to investigate the effect of bilge keels on the hull flow during steady turns for a displacement ship with a skeg and a bow dome. An Unsteady Reynolds Averaged Navier Stokes Solver (URANS) CFDShip-Iowa, Version 4, developed at the University of Iowa is used to simulate the flow around the Naval Surface Warfare Center-Carderock Division (NSWCCD) ship model# 5617 with bilge keels at different steady turning conditions. The effect of separated flows caused by the bilge keels and the skeg during steady turns on the flow distributions at the propeller plane will greatly influence the flow at the propeller planes. It was observed that during a high speed port turn at full rudder angle, the onset flow to the port side bilge keel was mainly influenced by the flow around the bow dome and the onset flow to the starboard side bilge keel was subject to the free stream hull flow. The drift angle varies along the bilge keel span during steady turning and complex vortical flow structures were developed on the leeward side of the bilge keels due to flow separations caused by the flow over the tip of the bilge keel from the windward side to the leeward side. The vortical flow generated by the starboard bilge keel also merged with the separated flow caused by the skeg and form a streamwise vortical structure that was convected downstream into the propeller plane. The wake field at both port and starboard propeller planes were analyzed from the simulation results. It can be concluded from the analysis that the starboard side propeller plane was subject to a uniform cross flow and the port side propeller plane was subject to a cross flow that consisted of both cross flow component and a mean swirl that was caused by the streamwise vortical flow generated by the flow separation upstream. The cross flow component at the propeller planes can effectively produce side force affecting the lateral motion of the ship. It can be concluded from the simulations that the bilge keels have great influence on the wake distributions at the propeller planes and can affect the propeller performance during maneuvering in terms of hydrodynamic and structural loadings. Great care should be taken to ensure that the bilge keels be designed properly in the future not just for both seakeeping and propulsion, but also for maneuvering.