Populism and foreign aid

Pundits, development practitioners, and scholars worry that rising populism and international disengagement in developed countries have negative consequences on foreign aid. However, how populism and foreign aid go together is not well understood. This paper provides the first systematic examination of this relationship. We adopt the popular ideational definition of populism, unpack populism into its core “thin” elements, and examine them within a delegation model of aid policy—a prominent framework in the aid literature. In so doing, we identify specific domestic political processes through which the core components of populism may affect aid spending. We argue that increases in one component of populism—anti-elitism—and in nativist sentiments, an associated concept, in a donor country lead to a reduction in aid spending through a public opinion channel. We supply both micro- and macro-evidence for our arguments by fielding surveys in the United States and United Kingdom as well as by analyzing aid spending by a large number of OECD donors. Our findings show that nativism and anti-elitism, rather than populism per se, influence not only individual attitudes toward aid but also actual aid policy and generate important insights into how to address populist challenges to foreign aid. Beyond these, our study contributes to the broader International Relations literature by demonstrating one useful analytical approach to studying populism, nativism, and foreign policy.

About the possibility of application of laser vacuum welding for the integration of elements of heat-protective structures from powder materials

The results of studying the process of laser vacuum welding of elements of heat-shielding panels made of heat-resistant dispersion-strengthened powder materials Ni-20Cr-6Al-Ti-Y2O3 of increased strength are presented. Such materials can be used to create ultralight heat-shielding panels, which are systems integrated on the surface of aircraft from typical modules of a cellular structure. Technical solutions of heat-insulating modules are considered, which are a cellular (honeycomb) structure consisting of two plates with a thickness of 0.1 to 0.14 mm, inside which there is a thin honeycomb filler. It is shown that the small thickness of the plates and the complexity of integrating the elements into a single system significantly impair the formation of a strong connection of such elements and do not allow the direct use of the known methods of diffusion welding or vacuum brazing. It has been established that laser welding of elements of heat-shielding structures in vacuum provides satisfactory strength of the structure of the heat-shielding element as a whole. Local heating at certain points prevents deformation of the parts to be joined during the welding process. The use of a pulsed Nd:Yag laser with a power of 400–500 W, operating in the frequency range of 50–200 Hz, allows welding with or without a filler powder. It was found that the use of filler additives practically does not affect the mechanical properties of the welded joint, however, it reduces the melt zone, while increasing the density of the welded joint. Based on the results obtained, it was concluded that it is possible to use laser vacuum welding for the integration of thin elements of heat-shielding modules. It is shown that a satisfactory joint strength is achieved by ensuring high cleanliness of the surfaces of elements before welding, maintaining a high vacuum (less than 10–2 Pa) and rational thermal loading of the surfaces of the elements to be integrated. The use of the proposed process makes it possible to obtain a stronger and denser seam in comparison with the known methods of soldering multicomponent powder dispersion-strengthened materials

DEPENDENCE OF THE FREQUENCY SPECTRUM OF MICRO- AND NANO- RESONATORS ON PRESSURE AND ATTACHED MASS

An elastic rod of circular or rectangular section is rigidly fixed on both ends. The applicability of classical equations for the deformation of thin elements like rods, plates and shells to describe the stated problem is assessed using such integral characteristics, as eigenfrequencies. The assembly pressure is uniform, specifically atmospheric, and acts also on the areas of strip edges. It is assumed that there are no strains in this case. Excess pressures act only on the strip’s surface. The self-weight of the strip is neglected. Accounting for the attached mass of the surrounding medium and radiation penetrating into it shows that pressures in the upper and lower parts of the rod differ. But these factors are not taken into account, which can be justified in case of light gases. Since the relative axial lengthening at the boundaries equals zero in case of rigid clamping, it will also equal zero along the entire length in the absence of external axial forces. Frequency equations have been derived in case of the action of the surrounding pressure and also uniformly distributed and attached point masses. The influence of the excess pressure of the surrounding medium on the frequency spectrum of the rod oscillations is determined by the non-dimensional parameter that increases with an increase in pressure and the rod length and decreases with an increase of bending rigidity. At the negative excess pressure (vacuuming) this parameter reverses its sign, and the frequencies become lower. With an increase in both distributed and attached point mass the eigenfrequencies of oscillations decrease due to the rod invariable bending rigidity. The displacement of the point mass towards the center results in a decrease in odd eigenfrequencies, while even eigenfrequencies remain the same. Using the first frequency measured we can determine the excess pressure acting on the rod’s surface. Using two frequencies of bending oscillations we can determine the attached point mass and its coordinate. These results can be used when simulating the performance of resonators, including micro and nano ones.

New mixed finite elements for the discretization of piezoelectric structures or macro-fiber composites

We propose a new three-dimensional formulation based on the mixed tangential-displacement normal-normal-stress method for elasticity. In elastic tangential-displacement normal-normal-stress elements, the tangential component of the displacement field and the normal component of the stress vector are degrees of freedom and continuous across inter-element interfaces. Tangential-displacement normal-normal-stress finite elements have been shown to be locking-free with respect to shear locking in thin elements, which makes them suitable for the discretization of laminates or macro-fiber composites. In the current paper, we extend the formulation to piezoelectric materials by adding the electric potential as degree of freedom.

Tensile strength of carbon rovings impregnated with different materials under anodic polarization

Carbon textiles are used more and more as reinforcement in concrete structures. Due to their high durability the concrete covers can be extremely thin compared to traditional steel reinforced concrete, resulting in the possibility to build very thin elements with excellent performance. To improve the properties of the carbon textiles, the rovings are normally impregnated with different types of polymers. Additionally to the use as reinforcement, carbon textiles can also be used as anodes for cathodic protection. However, while first tests have shown, that impregnated carbon rovings are suitable to be used as CP-anodes, it is still not clear under which conditions the new types of anodes are stable or when they start to dissolve. This paper describes investigations on the influence of an anodic polarisation on the tensile strength of different types of impregnated carbon rovings.

MEMS mirrors using sub-wavelength High- Contrast-Gratings with asymmetric unit cells

High-contrast gratings (HCG) are ultra-thin elements operating in sub-wavelength regime with the period of the grating smaller than the wavelength and with the high-index grating material fully surrounded by low-index material. Design of MEMS mirrors made from HCG with specific reflectivity response is of great practical interest in integrated optoelectronics. We theoretically investigate design of the spectral response for HCGs with the complex unit cells. We show that the spectral response can be tailored via the unit cell perturbations and with the asymmetric unit cell perturbations may introduce completely new spectral response. Our results can serve as guidance for the design of the complex HCGs and help with the choice of the efficient initial grating topology prior to global optimization procedure.