947 resultados para Arc shaped stator induction machine
Resumo:
This paper presents a combined experimental, numerical, and theoretical study on the mechanical behaviors of track-shaped concrete-filled steel tubular (SCFRT) stub columns stiffened by rebars under compressive load. A total of 18 track-shaped concrete-filled steel tubular specimens including 12 specimens stiffened by rebars and 6 non-stiffened counterparts are tested, with consideration of parameters including flakiness ratio, concrete strength, and stiffeners. Failure pattern, bearing capacity, and ductility are all analyzed and discussed based on the experimental results. The numerical simulation by finite element (FE) software ABAQUS is also conducted. Based on both experimental and numerical results, theoretical formula to predict the load-bearing capacity of SCFRT stub columns subjected to axial compression loading is established according to the superposition principle of ultimate load-bearing capacity with rational simplification. The proposed theoretical method provides accurate predictions on the load bearing capacity by comparing with experimental results from 18 groups of specimens.
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In this paper, we consider the bi-criteria single machine scheduling problem of n jobs with a learning effect. The two objectives considered are the total completion time (TC) and total absolute differences in completion times (TADC). The objective is to find a sequence that performs well with respect to both the objectives: the total completion time and the total absolute differences in completion times. In an earlier study, a method of solving bi-criteria transportation problem is presented. In this paper, we use the methodology of solvin bi-criteria transportation problem, to our bi-criteria single machine scheduling problem with a learning effect, and obtain the set of optimal sequences,. Numerical examples are presented for illustrating the applicability and ease of understanding.
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Road transport plays a significant role in various industries and mobility services around the globe and has a vital impact on our daily lives. However it also has serious impacts on both public health and the environment. In-vehicle feedback systems are a relatively new approach to encouraging driver behaviour change for improving fuel efficiency and safety in automotive environments. While many studies claim that the adoption of eco-driving practices, such as eco-driving training programs and in-vehicle feedback to drivers, has the potential to improve fuel efficiency, limited research has integrated safety and eco-driving. Therefore, this research seeks to use human factors related theories and practices to inform the design and evaluation of an in-vehicle Human Machine Interface (HMI) providing real-time driver feedback with the aim of improving both fuel efficiency and safety.
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In this paper, a novel 12-sided polygonal space vector structure is proposed for an induction motor drive. The space vector pattern presented in this paper consists of two 12-sided concentric polygons with the outer polygon having a radius double the inner one. As compared to previously reported 12-sided polygonal space vector structures, this paper subdivides the space vector plane into smaller sized triangles. This helps in reducing the switching frequency of the inverters without deteriorating the output voltage quality. It also reduces the device ratings and dv/dt stress on the devices to half. At the same time, other benefits obtained from the existing 12-sided space vector structure, such as increased linear modulation range and complete elimination of 5th and 7th order harmonics in the phase voltage, are also retained in this paper. The space vector structure is realized by feeding an open-end induction motor with two conventional three-level neutral point clamped (NPC) inverters with asymmetric isolated dc link voltage sources. The neutral point voltage fluctuations in the three-level NPC inverters are eliminated by utilizing the switching state multiplicities for a space vector point. The pulsewidth modulation timings are calculated using sampled reference waveform amplitudes and are explained in detail in this paper. Experimental verification on a laboratory prototype shows that this configuration may be considered suitable for high power drives.
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The aim of this thesis was to study what kind of home-made menstrual pads were used in the early 20th century in Finland, how the home-made pads were made and which techniques and materials were used. The use and taking care of menstrual pads were also explored. The history of menstrual pads has been studied in Sweden, Germany and United States but none of those studies has concentrated on home-made pads. Instead, there are many studies about womanhood and menstruation. In many studies home-made menstrual pads are only briefly mentioned. Menstrual pads were not commonly used in Finland at the beginning of the 20th century, but already in the 1940s the use of menstrual pads had become common in every stratum of society. Home-made menstrual pads were used even until the 1960s. In Finland, factory-made disposable menstrual pads became common only in the 1930s and they were only slowly accepted. The study material consisted of nine interviews, three archival inquiries, health care guidebooks from 1893 to 1943 and authentic menstrual pads, menstrual belts and other objects related to them. The interviewed women were born between 1915 and 1939. The narrative approach was used in the study and it also guided the analysis. The interview and archival data were studied according to the basic rules of oral history studies. Literature consisted of publications from several disciplines. The extensive primary material played the most important role in this study. The reconstructions of the menstrual pads were made according to the interviewed women s advice. In Finland there were innumerable variations of home-made menstrual pads. The pads were most commonly crocheted and knitted either by hand or by knitting machine. Pads were also sewn of cloth, old bed linen or old underwear. The menstrual pads were self-made or made by a female relative. Word of mouth was important in spreading information on how to make pads, because there were hardly any instructions available. The biggest pads were 54 cm long and 13 cm wide. The most widely used pad model was a rectangle, which had triangle-shaped ends with a buttonhole or a loop. The pad was attached to the menstrual belt or to the buttons of the suspender belt. Knitted and crocheted pads had one, two or three layers. In sewn pads, there could be even more layers. Cellulose wadding or pieces of cloth could be placed inside the pad to increase the absorption ability. The experiences of the comfort of self-made pads varied. The crocheted and sewn pads were found chafing, knitted ones were found soft and comfortable. The menstrual pads were laborious to wash and boil in lye water. Therefore disposable pads made everyday life easier. The home-made menstrual pads were part of a unique tradition of handicrafts and folk culture. Hand-made pads were one of the most common handicraft products and were a part of every woman s life. Even so, the menstrual pads were unnoticeable. The large number of variations was probably caused by the silence around menstrual topics and by the lack of instructions for making pads. Variations are also explained by the uniqueness of every handicraft product. In Finland the home-made pads were used until relatively recent times. This was caused by the conditions of wartime and the following years and the rarity of commercial pads. Furthermore, until the late 20th century Finland was an agricultural society where all innovations spread slowly. Home-made menstrual pad was a secret handicraft of women and every woman needed to know how to make it by herself.
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Employing a specific radioimmunoassay for quantification, the kinetics of estrogen-induced elevation in the plasma concentration of biotin-binding protein (BBP) in immature male chicks was investigated. A single injection of the steroid hormone enhanced the plasma BBP content several-fold at 6 h, reaching peak levels around 48 h and declining thereafter. A 2-fold amplification of the response was evident during secondary stimulation with the hormone. The magnitude of the response was hormonal dose-dependent while the initial lag phase and the time of peak protein accumulation were unaltered within the hormonal doses tested. The circulatory half-life of the specific protein in normal and estrogenized birds was 10 h. Hyperthyroidism markedly decreased the hormonal response while the opposite effect was seen during hypothyroidism. The antiestrogens E- and Z-clomiphene citrate effectively blocked the protein induction whereas progesterone, either alone or in combination with estrogen, was ineffective in modulating the induction. Cycloheximide administration drastically inhibited the inductive response. The above observations clearly suggest that the genes corresponding to the two isofunctional proteins of chicken egg, viz. BBP and avidin, are differentially regulated.
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The permanent mammalian kidney (metanephros) develops as a result of complex reciprocal tissue interactions between a ureteric epithelium and the renal mesenchyme. The overall goal of the research in this thesis was to gain data that will eventually help in elucidating the formation of congenital renal malformations. The experiments in my thesis aimed to reveal the mechanisms by which Notch, Wnt and GDNF/Ret signalling pathways regulate the development of functional kidney. The function of Notch pathway was studied by a transgenic mouse model, where it was shown that overactivation of Notch signalling disturbs kidney development and alters the expression of Gdnf and Ret/GFRa1. This indicates that Notch signalling interplays with GDNF/Ret in the regulation of the primary ureteric budding and its subsequent branching. The data also suggested that strict spatio-temporal regulation of these two pathways is required for determination of ureteric tip-identity, which appeared to be crucial for the branch formation. The function of Wnt signalling in the ureteric morphogenesis was studied by in vivo and in vitro methods to show that a canonical pathway is required for ureteric branching. Stabilisation and deletion of the canonical pathway mediator, b-catenin specifically in the ureteric epithelium result in renal aplasia/hypodysplasia. These defects originate from severe blockage of ureteric branching due to the disrupted Ret signalling. Consequently, ureteric tip specific markers are lost and ureteric stalk identity is expanded throughout the whole epithelium. Thus, the data demonstrates that the Wnt/b-catenin pathway plays an essential role in the patterning and branching of the ureteric epithelium. A novel in vitro method was generated and utilised in nephron induction studies to reveal the mechanisms through which nephrogenesis is induced. Transient GSK3 inhibition results in stabilisation of b-catenin in the isolated renal mesenchyme, which efficiently triggers nephron formation. Also genetic stabilisation of b-catenin specifically in the mesenchyme results in spontaneous nephrogenesis. The results show that activation of the canonical Wnt pathway is sufficient to initiate nephrogenesis, and suggest that this pathway mediates the nephron induction in murine kidney mesenchymes. Taken together, this thesis demonstrates Notch and Wnt signalling pathways as novel regulators of ureteric branching morphogenesis, and that activation of the canonical Wnt pathway is sufficient for nephron induction. The studies also indicate that the Notch and Wnt pathways cross-talk with GDNF/Ret signalling in the patterning of ureteric epithelium.
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Ulva is a common component of marine intertidal flora in Australia with many species frequently observed along the Queensland coastline. Three species of Ulva, U. lactuca, U. intestinalis and U. prolifera were found to naturally occur at the Bribie Island Research Centre (BIRC) in Southeast Queensland. Studies were undertaken to establish the most optimal conditions for growing Ulva in the BIRC laboratory. These tests were conducted in order to condition the algal material prior to the sporulation studies, offering more controlled material to assess treatment effects conclusively, and helping eliminate other potentially confounding environmental factors. Results showed that a stocking density of between 5-20 grams of Ulva per litre along with the addition of the soluble fertiliser Aquasol at a rate of 87 mg/L of seawater was ideal for achieving a desired doubling of growth per week. In the wild the formation of Ulva fragments occurs naturally in the ocean through wave and storm action. This breakage can trigger a survival response mechanism which stimulates the algae to form and release gametes. By chopping the tissue, this process could be artificially simulated in the laboratory and creating a simple and easy way to produce new individuals. Studies performed into inducing sporulation in Ulva through a combination of fragmentation and renewal of medium at BIRC showed that sporulation can be successfully induced in all three species of Ulva through these methods, however it was found to be to a degree that would not meet the demands of commercial production with on average a rate of only 33% achieved. While the current study did not find a method suitable for a commercial application the results presented here contribute to increasing our understanding about Ulva reproduction and set a platform for future work in to cultivating Ulva within Southeast Queensland.
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Live recombinant Saccharomyces cerevisiae yeast expressing the envelope antigen of Japanese encephalitis virus (JEV) on the outer mannoprotein layer of the cell wall were examined for their ability to induce antigen-specific antibody responses in mice. When used as a modelantigen, parenteral immunization of mice with surface-expressing GFP yeast induced a strong anti-GFP antibody response in the absence of adjuvants. This antigen delivery approach was then used for a more stringent system, such as the envelope protein of JEV, which is a neurotropic virus requiring neutralizing antibodies for protection.Although 70% of cells were detected to express the total envelope protein on the surface by antibodies raised to the bacterially expressed protein, polyclonal anti-JEV antibodies failed to react with them. In marked contrast, yeast expressing the envelope fragments 238-398, 373-399 and 373-500 in front of a Gly-Ser linker were detected by anti-JEV antibodies as well as a monoclonal antibody but not by antibodies raised to the bacterially expressed protein. Immunization of mice with these surface-expressing recombinants resulted in a strong antibody response. However, the antibodies failed to neutralize the virus, although the fragments were selected based on neutralizing determinants.
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This paper presents the results on a resin-rich machine insulation system subjected to varying stresses such as electrical (2.6 to 13.3 MV/m) and thermal (40 to 155° C) acting together. Accelerated electro-thermal aging experiments subsequently have been performed to understand the insulation degradation The interpretations are based on several measured properties like capacitance, loss tangent, ac resistance, leakage current, and partial discharge quantities. The results indicate that the changes in properties are not significant below a certain temperature for any applied stress, Beyond this temperature large variations are observed even for low electrical stresses. Electrothermal aging studies reveal that the acceleration of the insulation degradation and the ultimate time to failure depends on the relative values of temperature and voltage stresses. At lower temperatures, below critical, material characteristics of the system predominate whereas beyond this temperature, other phenomena come into play causing insulation deterioration. During aging under combined stresses, it appears that the prevailing temperature of the system has a significant role in the insulation degradation and ultimate failure.
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This briefing paper presents and foreshadows ongoing PhD research by the first author into how understandings of organised crime in Australia have been shaped, and the extent to which these perceptions have influenced legislative and policing responses. It begins with an historical survey of significant models of organised crime, then reviews current Australian legislative strategies, and goes on to raise questions about the conceptual model that underpins these strategies. The paper concludes with a discussion of the potential policy implications of this research.
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In recent years more and more complex humanoid robots have been developed. On the other hand programming these systems has become more difficult. There is a clear need for such robots to be able to adapt and perform certain tasks autonomously, or even learn by themselves how to act. An important issue to tackle is the closing of the sensorimotor loop. Especially when talking about humanoids the tight integration of perception with actions will allow for improved behaviours, embedding adaptation on the lower-level of the system.
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Estrogen (E) induction of riboflavin carrier protein (RCP) in the chicken oviduct and liver was investigated to compare and contrast the kinetics, hormonal specificity and modulation of its elaboration in the 2 steroid-responsive tissues. During primary stimulation, continued daily E administration to immature female chicks elicited, after an initial lag, rapid growth and RCP content of the oviduct; neither progesterone (P) nor testosterone (T) could substitute for E in this respect. Furthermore, P given along with E curtailed tissue growth and its RCP content, whereas E + T had a synergistic effect on tissue growth only. During secondary stimulation, E administration steeply enhanced both tissue weight and RCP content without any lag. Interestingly, P (but not T) could substitute for E in augmenting magnum RCP concentration to a comparable extent while a concomitant effect on tissue growth was less marked. In contrast, hepatic induction of RCP was absolutely E-specific during both primary and secondary stimulations. Secondary stimulation with either E or P of E-primed birds enhanced the rates of RCP synthesis in the oviduct relative to that of total protein, whereas in the liver only E was effective in this regard. The absolute rate of E-induced RCP synthesis in both the steroid-stimulated tissues was significantly higher than that of general protein elaboration.
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Administration of the anti-hypercholesterolaemic drug clofibrate to the rat increases the activity of carnitine acetyltransferase (acetyl-CoA-carnitine -acetyltransferase, EC 2.3.1.7) in liver and kidney. The drug-mediated increase in enzyme activity in hepatic mitochondria shows a time lag during which the activity increases in the microsomal and peroxisomal fractions. The enzyme induced in the particulate fractions is identical with one normally present in mitochondria. The increase in enzyme activity is prevented by inhibitors of RNA and general protein synthesis. Mitochondrial protein-synthetic machinery does not appear to be involved in the process. Immunoprecipitation shows increased concentration of the enzyme protein in hepatic mitochondria isolated from drug-treated animals. In these animals, the rate of synthesis of the enzyme is increased 7-fold.
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A new technique for reducing the torque pulsations in a conventional current source inverter fed induction motor drive is presented. This does not attempt to improve the current waveforms, but modifies the airgap MMF directly. This is based on the use of a motor with two sets of balanced phase windings, with a 30 electrical degree phase difference between them, and each set being fed from a conventional current source inverter. The two inverters are further connected in series so that they can operate from the same current source. As a consequence of this arrangement, the voltage rating of the components of each inverter is reduced, along with reduced torque ripple. This scheme has been experimentally verified and compared with the performance of a conventional scheme.