Experimental Study of Plasma Actuator Effects on Flow Field Separation Bubble around Blunt Flat Plate

In this paper, the air flow around a blunt flat plate with a rounded leading edge has been experimentally examined with and without the presence of a plasma actuator. Tests have been conducted with Reynolds numbers ranging from 104 to 105. Significant phenomena in this flow field is the flow separation at the leading edge of the body, which called separation bubble. There are two considerably dimensionless parameters in this experiment. One of them is the leading edge radius ratio to body thickness and other one is the ratio of maximum velocity induced by plasma actuator to free stream velocity. Geometries with the values of R/D=0, 1/16, 2/16, 4/16 were tested. For each geometry, the effectiveness of plasma actuator on the separation bubble is studied in different values of velocity ratio. The results show that, the effect of plasma actuator for the geometry with sharp edge (R/D=0), is negligible, while in geometry with rounded edge, the plasma actuator has significant effect on the separation bubble domain. This effectiveness is enhanced, by increasing of leading edge radius and velocity ratio, so that in rounded edge geometry (R/D=4/16) length of separation bubble is reduced about 75%

Bad governance:How privatization increases corruption in the developing world

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

Distribution function and atomization parameters of petroleum fuels sprays: An experimental and numerical study

Heavy fuels are difficult to spray. To investigate the burning of this fuel and create an appropriate combustion chamber, one must first understand the atomization process and spray properties of petroleum fuels. The Diesel spray behavior compared to Mazut fuel spray gives us an understanding of the atomization phenomenon of fuels. The most crucial fuel atomization characteristics include droplet diameter, spray angle, breakdown length, and droplet distribution. The shadowgraphy technique is used to capture images of fuel spray, which are then processed using image analysis software. The size and speed of the fuel spray droplets are predicted using the maximum entropy method. From a pressure difference of 15 bar onwards, the rate of mass flow remains almost constant. The fuels spray cone angle initially increases, and after the flow approaches full atomization, it reaches approximately a constant value. The breakup length and droplets diameter decrease with increasing fuel temperature and pressure, and with the full development of the flow, they tend to almost zero. By raising the fluid's viscosity, the diameter size distribution of the droplets becomes more uniform and smooth (unlike velocity distribution). In this research, an attempt has been made to develop experimental and numerical methods to measure the powdering parameters of a heavy non-Newtonian oil fuel called Mazut and a light petroleum fuel called diesel, as well as to investigate the spray behavior of these fuels

The Political Resource Curse

Extant theoretical work on the political resource curse implies that dependence on resource revenues should decrease autocracies’ likelihood of democratizing but not necessarily affect democracies’ chances of survival. Yet most previous empirical studies estimate models that are ill-suited to address this claim. We improve upon previous studies, estimating a dynamic logit model using data from 166 countries, covering the period from 1816 to 2006. We find that an increase in resource dependence decreases an autocracy’s likelihood of being democratic over both the short term and long term but has no appreciable effect on democracies’ likelihood of persisting