70 research outputs found

    Towards Optimal Designing of thin elastic Plates with a specific free Oscillations Frequency

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    Thin elastic plates are the basic constructional elements and are very often subjected to dynamic effects especially in the machine-building structures. Their saving design of resonance conditions of operation is an extremely complicated task which cannot be solved analytically. In the present report an efficient and sufficiently general method for optimal design of thin plates is worked out on the basis of energy resonance method of Wilder, the method of the finite elements for dynamic research and the methods of parameter optimization. By means of these methods various limitations and requirements put by the designer to the plates can be taken into account. A programme module for numerical investigation of the weight variation of the plate depending on the taken variable of the designed thickness at different supporting conditions is developed. The reasons for the considerable quantity and quality difference between the obtained optimal designs are also analysed

    SYZ mirror symmetry for hypertoric varieties

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    We construct a Lagrangian torus fibration on a smooth hypertoric variety and a corresponding SYZ mirror variety using TT-duality and generating functions of open Gromov-Witten invariants. The variety is singular in general. We construct a resolution using the wall and chamber structure of the SYZ base.Comment: v_2: 31 pages, 5 figures, minor revision. To appear in Communications in Mathematical Physic

    Credibility and adjustment: gold standards versus currency boards

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    It is often maintained that currency boards (CBs) and gold standards (GSs) are alike in that they are stringent monetary rules, the two basic features of which are high credibility of monetary authorities and the existence of automatic adjustment (non discretionary) mechanism. This article includes a comparative analysis of these two types of regimes both from the perspective of the sources and mechanisms of generating confidence and credibility, and the elements of operation of the automatic adjustment mechanism. Confidence under the GS is endogenously driven, whereas it is exogenously determined under the CB. CB is a much more asymmetric regime than GS (the adjustment is much to the detriment of peripheral countries) although asymmetry is a typical feature of any monetary regime. The lack of credibility is typical for peripheral countries and cannot be overcome completely even by “hard” monetary regimes.http://deepblue.lib.umich.edu/bitstream/2027.42/40078/3/wp692.pd

    Bad governance:How privatization increases corruption in the developing world

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    International organizations have become key actors in the fight against corruption. Among these organizations, the International Monetary Fund (IMF) maintains a powerful position over borrowing countries in its ability to mandate far‐ranging policy reforms – so‐called “conditionalities” – in exchange for access to financial assistance. While IMF pressure can force the implementation of anti‐corruption policies, potentially reducing corruption, other IMF policy measures, such as the privatization of state‐owned enterprises, can create rent‐extraction opportunities and limit the capacity of state institutions to limit corrupt behavior. To test these mechanisms, we conduct instrumental‐variable regression analysis using an original dataset on IMF conditionality for up to 141 developing countries from 1982 to 2014. We find that conditions to privatize state‐owned enterprises exert significant detrimental effects on corruption control. Conversely, other areas of IMF intervention are not consistently related to corruption abatement. These findings offer policy lessons regarding the design of conditionality, which should avoid large‐scale privatization, especially under conditions of weak accountability

    The tectonics of the western Ordos Plateau, Ningxia, China: Slip rates on the Luoshan and East Helanshan Faults

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    Analysis of the locus, style, and rate of faulting is fundamental to understanding the kinematics of continental deformation. The Ordos Plateau lies to the northeast of Tibet, within the India-Eurasia collision zone. Previous studies have suggested that it behaves rigidly and rotates anticlockwise within a large-scale zone of ENE-WSW left-lateral shearing. For this rotation to be accommodated, the eastern and western margins of the Ordos Plateau should be undergoing right-lateral shearing and yet the dominant faulting style appears to be extensional. We focus specifically on the kinematics of the faults bounding the western margin of the Ordos Plateau and make new slip rate estimates for two of the major faults in the region: the right-lateral strike-slip Luoshan Fault and the normal-slip East Helanshan Fault. We use a combination of infrared stimulated luminescence dating of offset landforms with high-resolution imagery and topography from the Pleiades satellites to determine an average right-lateral slip rate of 4.3 ± 0.4 mm/a (1σ uncertainty) on the Luoshan Fault. Similarly, we use 10Be exposure dating to determine a vertical throw rate on the East Helanshan Fault of <0.6 ± 0.1 mm/a, corresponding to an extension rate of <0.7 ± 0.1 mm/a (1σ uncertainty). Both of these results agree well with slip rates determined from the latest campaign GPS data. We therefore conclude that right-lateral shearing is the dominant motion occurring in the western Ordos region, supporting a kinematic model of large-scale anticlockwise rotation of the whole Ordos Plateau

    Utilization of Waste Nitrocellulose Propellants by Obtaining Porous Materials

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    Technology for utilization of waste single and double based propellants by obtaining porous propellants was worked out. The technology contains the preparation of solutions of waste propellants with concentration up to 20%, mixing with additives, forming a liquid layer with determined thickness, evaporation of some amount of the solvent, leaching liquid components with water and draying the porous propellants. The time for evaporation of some amount of the solvent was determined from the results of the rates of evaporation. The investigated additives were 1-butanol, ethylene glycol and polyethylene glycol 400. The porous propellants with specific density from 0.5 to 0.7 g/cm3 and regular distribution of voids of dimensions from 0.1 to 500 žm were obtained

    Testicular germ-cell tumors - epidemiology and etiology

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    Testicular cancer is one of the most common malignancies among young men in the age group 15-40 with peak of incidence in the third decade. Testicular germ cell carcinoma accounts for about 95-97 % of all malignant testicular cancers. Around half of this group is presented by seminomas and the other half is mixed group named as nonseminomas including choriocarcinomas, teratomas, embryonal cell carcinoma, tumor yolk sac. This group of tumors is not evenly spread around the world. It has highest density in North Europe and Denmark and Slovenia in particular. Many risk factors have been blamed to be responsible for cancerogenesis in this group but for the time being there are few proven theories. Along with the epidemiological statistic data new scientific revelations shown and proved heredity of testicular carcinoma in specific genetic lines. In other studies indirect evidence supports that hormonal misbalance even "in utero" can cause conditions for developing malignant cells in the testicular parenchyma. There is still an open issue the reason for deference in density among different countries shearing neighbor territories.SSM, 2012;44(1):57-6
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