U.S.-Ukraine Military Relations and the Value of Interoperability

Ukraine\u27s destiny is critical to the security of the entire post-Soviet zone. It long has been the stated goal of Ukrainian defense policy to integrate with Euro-Atlantic structures like the North Atlantic Treaty Organization (NATO), and this goal has been one of the chief objectives of the United States, as well. However, to move from rhetoric to implementation is particularly difficult where the defense reform of a post-Soviet state has been concerned, and Ukraine is no exception. Ukraine has begun to make remarkable progress towards its self-professed goal of defense integration with Western structures. This monograph provides a comprehensive account of Ukrainian-American defense relations and of Ukraine\u27s defense reforms over the period since Ukraine became independent in 1991. It clearly points out both the obstacles and the successes that both partners have encountered in building a cooperation mechanism, in practical peacetime engagement, and in accomplishing missions together, as well as outlining the challenges ahead. Given that Ukraine is a major contributor to the stabilization forces in Iraq and a key player in any European and Eurasian security order, this monograph has real policy relevance, especially as the United States seeks to work with its allies and partners in other post-Soviet states to foster their defense and political integration with the West.https://press.armywarcollege.edu/monographs/1759/thumbnail.jp

The method of long-life calculation for a friction couple “rotor – hybrid bearing”

Reliability of rotating machinery is determined to a considerable degree by the bearing units. For several applications the requirements in rotation speed, bearing load and maximal vibration level are so extreme that neither rolling-element bearings nor fluid-film bearings could provide necessary performance characteristics during all regimes of operation. Hybrid bearings, which are a combination of rolling-element and fluid-film bearings, can improve performance characteristics and reliability of the rotor-bearing systems. The article presents the approach for to formation of the method of resource calculation for hybrid bearing with speed separation. The results show that the resource of the slide bearing increases significantly when it is used in combination with a rolling-element bearing compared to its single setting

Thermohaline structure and variability in the eastern Nansen Basin as seen from historical data

Newly available historical Russian data are used to quantify year-to-year variations in the structure and properties of the halocline and Atlantic Water layers in the eastern Nansen Basin. The data come from a series of aerial surveys of the central Arctic Ocean done during winter between 1973 and 1979, and repeated Polygon surveys of the shelf, slope, and basin north of Severnaya Zemlya in the 1980s, and thus allow a perspective on shelf-basin exchange. A water-mass census shows substantial survey-to-survey variability in several water-mass categories, with volumetric fluctuations of ∼17% in the Upper Polar Deep Water category, ∼14% in Atlantic Water, and ∼39% for cold surface waters with T \u3c −1.5°C. Mean water-mass production rates in the polygon area are found to be 0.6–1.2 Sv for Upper Polar Deep Water, and an effective loss rate of 0.75–1.5 Sv is found for Atlantic Waters. On average Atlantic Water loses 16% of its initial heat content within the 350 km-long survey area, possibly enhanced by double-diffusive processes. Mean upward heat fluxes above the Atlantic Water are estimated to be between 4 and 6 W/m2, based on heat budget considerations. Upward heat fluxes of this magnitude would have a major effect on sea ice, which is regularly observed to be thinner in this area of the Nansen Basin. Shallow-water profiles taken close to Severnaya Zemlya show cold and salty waters denser than offshore waters at similar depths, and evidence of convection is seen in many profiles taken over the continental shelf and slope, reflecting deep convective events extending in some cases below the deepest observed depth of 1000 m