171,850 research outputs found
Contro i "custodi di vetrine ben separate". Il Machiavelli di Papini
No full textGiovanni Papini interprete del "filosofo" Machiavell
F. Giampiccoli - C. Papini, L'Eredità del Valdesimo medievale, Claudiana, Turin, 1974
No full textAnsaldi Jean. F. Giampiccoli - C. Papini, L'Eredità del Valdesimo medievale, Claudiana, Turin, 1974. In: Revue d'histoire et de philosophie religieuses, 55e année n°3,1975. p. 464
F. Giampiccoli - C. Papini, L'Eredità del Valdesimo medievale, Claudiana, Turin, 1974
No full textAnsaldi Jean. F. Giampiccoli - C. Papini, L'Eredità del Valdesimo medievale, Claudiana, Turin, 1974. In: Revue d'histoire et de philosophie religieuses, 55e année n°3,1975. p. 464
Comparison of Surface Mounted and Uneven Consequent-Pole PM High-Speed Machines
No full textSurface mounted permanent magnet synchronous machines are nowadays used in a wide range of applications and power ratings, thanks to their high efficiency and ease of control. However, when used in high-speed applications, the need of some feature retaining the magnets increases the effective magnetic air gap, thus lowering the performance of the motor. This paper proposes a rather unconventional rotor structure based on the consequent pole arrangement. Different rotor topologies are discussed and compared
Thermal-Electromagnetic Analysis of Solid Rotor Induction Machine
No full textThe increasing demand for high speed, direct drive systems is driving a significant research effort on high speed electrical machines. Thermal management becomes a significant aspect to deal with as power loss per cooling surface area reduces as speed increases. Solid rotor induction machines are often considered at the high end of the speed spectrum as they offer a mechanically robust rotor structure. The current density distribution within their rotor structure typically results in high rotor losses and a significant portion of the total machine losses. In such machines the current distribution in the rotor itself is highly dependent on the rotor resistance and hence on the rotor temperature distribution. This paper will detail an effective model coupling both the electromagnetic and thermal domains to simulate operation of solid rotor induction machines
Sensitivity analysis of magnetizing inductance in solid rotor induction machine
No full textSolid Rotor Induction Machines (SRIM) gained lot of interesting in the last decades due to the increasing demand for high speed drives. The low manufacturing cost, the rotor robustness and the capability operating in of harsh environments comes along with the drawbacks of difficult design process, necessity of multi-physics analysis and poor power factor. The magnetizing inductance play an important role for what concerns the power factor. In this work the impact of the solid rotor material properties and the air gap of the machine on the magnetizing inductance is investigated
Infinitely many solutions for a Floquet-type BVP with superlinearity indefinite in sign
No full textBy the application of a technique developed by G. J. Butler we find infinitely many solutions of a Floquet-type BVP for the equation x''+q(t)g(x)=0, where q is a weight function that is allowed to change sign, g is is superlinear and such that g(x)x>0 for all non-zero x. The boundary condition is (x(b),x'(b))=L(x(a),x'(a)), where L is a continuous, positively homogeneous, and nondegenerate map. At first we apply the main result to obtain solutions with a prescribed large number of zeros when L is the rotation of a fixed angle l; second, we find infinitely many subharmonic solutions of any order and, again, solutions with a prescribed large number of zeros for the periodic problem associated to the equation x''+cx'+q(t)g(x)=0, with q and g as above and a constant c
Diagnostic strategies using DNA testing for hereditary haemochromatosis in at-risk populations: a systematic review and economic evaluation
No full textOBJECTIVE: To evaluate DNA testing for detecting hereditary haemochromatosis (HHC) in subgroups of patients suspected of having the disorder and in family members of those diagnosed with HHC. DATA SOURCES: Major electronic databases, searched from inception to April 2007. REVIEW METHODS: A systematic review was undertaken using a priori methods and a de novo model developed to assess costs and consequences of DNA testing. RESULTS: Eleven studies were identified for estimating the clinical validity of genotyping for the C282Y mutation for the diagnosis of HHC. No clinical effectiveness studies meeting the inclusion criteria were identified. Two North American cost-effectiveness studies of reasonable quality were identified but their generalisability to the UK is not clear. Three cohort studies met the inclusion criteria for the review of psychosocial aspects. All had methodological limitations and their generalisability is difficult to determine. The clinical sensitivity of C282Y homozygosity for HHC ranged from 28.4% to 100%, or from 91.3% to 92.4% when considering only the most relevant studies. Clinical specificity ranged from 98.8% to 100%. One study found that gene testing was a cost-effective method of screening relatives of patients with haemochromatosis, whereas the other found that genotyping the spouse of a homozygote was the most cost-efficient strategy. Genetic testing for haemochromatosis appears to be well accepted, is accompanied by few negative psychosocial outcomes and may lead to reduced anxiety. The de novo economic model showed that, in people suspected of having haemochromatosis, the DNA strategy is cost saving compared with the baseline strategy using liver biopsy (cost saved per case detected 123 pounds), largely because of the reduction in liver biopsies. For family testing of siblings the DNA strategy is not cost saving because of the costs of the DNA test (additional cost per case detected 200 pounds). If the cost of the test were to reduce from 100 pounds to 60 pounds, the DNA strategy would be the cheaper one. For family testing of offspring the DNA test strategy is cheaper than the baseline biochemical testing strategy (cost saved per case detected 7982 pounds). Sensitivity analyses showed that the conclusions in each case are robust across all reasonable parameter values. CONCLUSIONS: The preferred strategy in practice is DNA testing in conjunction with testing iron parameters when there is clear clinical indication of risk for haemochromatosis because of biochemical criteria or when there is familial risk for HHC. Access to genetic testing and centralisation of test provision in expert laboratories would lower the cost of testing, improve the cost-effectiveness of the strategy and improve the quality of information provided to clinicians and patients.<br/
Sensitivity analysis of rotor parameters in solid rotor induction machine
No full textSolid Rotor Induction Machines (SRIM) gained lot of interesting in the last decades due to the increasing demand for high speed drives. The low manufacturing cost, the rotor robustness and the capability operating in of harsh environments comes along with the drawbacks of difficult design process, necessity of multi-physics analysis and poor power factor. The single phase lumped parameter equivalent circuit is widely adopted for design and analysis purposes. The impact of the solid rotor material properties as saturation flux density, relative permeability and electrical resistivity are discussed in this work for what concerns mainly the rotor resistance and rotor leakage inductance. Finite Element simulations are performed to determine the equivalent circuit parameters dependencies on the solid material selected for the rotor structure
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