The NATO Response Force: A qualified failure no more?

With much fanfare, NATO declared its rapid reaction force—the NATO Response Force (NRF)—an Initial Operational Capability in 2004. This article addresses four questions: Where did the NRF come from? What does it look like in 2017? What have been the major obstacles for the NRF fulfilling its promises? And where is the NRF likely to go? The article holds two main arguments. First, due to inadequate fill-rates and disagreements as to the force’s operational role, the NRF was for many years a “qualified failure.” The force failed to become the operational tool envisioned by the allies in 2002. While not without effect, it fell hostage to the harsh reality of the expeditionary wars of Iraq and Afghanistan. Second, the NRF is off to a fresh beginning and will likely be considered at least a partial success by the allies in the years to come.     

A quasi-isentropic model of a cylinder driven by aluminized explosives based on characteristic line analysis

A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum (Al) reaction rate on cylinder expansion and the physical parameters of the detonation products. Based on the proposed quasi-isentropic hypothesis and relevant isentropic theories, the characteristic lines of aluminized explosives driving a cylinder were analyzed, and a quasi-isentropic model was established. This model includes the variation of the cylinder wall velocity and the physical parameters of the detonation products with the Al reaction degree. Using previously reported experimental results, the quasi-isentropic model was verified to be applicative and accurate. This model was used to calculate the physical parameters for cylinder experiments with aluminized cyclotrimethylenetrinitramine explosives with 15.0 % and 30.0 % Al content. The results show that this quasi-isentropic model can be used not only to calculate the cylinder expansion rule or Al reaction degree, but also to calculate the physical parameters of the detonation products in the process of cylinder expansion. For explosives with 15.0 % and 30.0 % Al, 24.3 % and 18.5 % of the Al was found to have reacted at 33.9 μs and 34.0 μs, respectively. The difference in Al content results in different reaction intensity, occurrence time, and duration of two forms of reaction (diffusion and kinetic) between the Al powder and the detonation products; the post-detonation burning reaction between the Al powder and the detonation products prolongs the positive pressure action time, resulting in a continuous rise in temperature after detonation.     

领悟社会支持与高中生学习投入的关系:自尊和未来教育规划的链式中介作用

目的:探究领悟社会支持对学习投入的影响,以及自尊和未来教育规划的链式中介效应。方法:采用领悟社会支持量表、自尊量表、未来教育规划问卷和学习投入量表,对446名高中生进行施测。结果:①各变量两两之间均存在显著地正相关(r=0.32~0.50,p<0.001);②领悟社会支持能正向预测高中生学习投入;③在领悟社会支持对高中生学习投入的预测中存在三条路径:一是自尊的中介作用;二是未来教育规划的中介作用;三是自尊和未来教育规划的链式中介作用,效果值分别为:14.81%,27.78%和16.67%。结论:领悟社会支持不仅直接影响高中生学习投入,还通过自尊和未来教育规划影响高中生学习投入。     

Study of simple plane wave generator with an air-metal barrier

Plane wave generators (PWGs) are used to accelerate flyer plates to high velocities with their generated plane waves, which are widely used in the test of dynamic properties of materials. The traditional PWG is composed of two explosives with different detonation velocities. It is difficult to implement the related fabrication processes and control the generated waves due to its complicated structures. A simple plane wave generator is presented in this paper, which is composed of two identical cylindrical high explosive (HE) charges and an air-metal barrier. A theoretical model was established based on two different paths of the propagation of detonation waves, based on which the size of air-metal barrier was calculated for a given charge. The corresponding numerical simulations were also carried out by AUTODYN-2D^® based on the calculated results, which were used to compare with the theoretical calculations. A detonation wave with a flatness of 0.039 μs within the range of 70-percent diameter of the main charge was obtained through the simulations.     

Neural network modeling to evaluate the dynamic flow stress of high strength armor steels under high strain rate compression

An artificial neural network (ANN) constitutive model is developed for high strength armor steel tempered at 500 °C, 600 °C and 650 °C based on high strain rate data generated from split Hopkinson pressure bar (SHPB) experiments. A new neural network configuration consisting of both training and validation is effectively employed to predict flow stress. Tempering temperature, strain rate and strain are considered as inputs, whereas flow stress is taken as output of the neural network. A comparative study on Johnson–Cook (J–C) model and neural network model is performed. It was observed that the developed neural network model could predict flow stress under various strain rates and tempering temperatures. The experimental stress–strain data obtained from high strain rate compression tests using SHPB, over a range of tempering temperatures (500–650 °C), strains (0.05–0.2) and strain rates (1000–5500/s) are employed to formulate J–C model to predict the high strain rate deformation behavior of high strength armor steels. The J-C model and the back-propagation ANN model were developed to predict the high strain rate deformation behavior of high strength armor steel and their predictability is evaluated in terms of correlation coefficient (R) and average absolute relative error (AARE). R and AARE for the J–C model are found to be 0.7461 and 27.624%, respectively, while R and AARE for the ANN model are 0.9995 and 2.58%, respectively. It was observed that the predictions by ANN model are in consistence with the experimental data for all tempering temperatures.     

Ireland's Ho Chi Minh trail? The Republic of Ireland's role in the Provisional IRA's bombing campaign, 1970–1976

A common criticism levelled at successive governments of the Republic of Ireland during the Northern Ireland ‘Troubles’ was their alleged inactivity in the face of a ferocious Provisional IRA campaign. Such criticisms were based in large part on the perception of the southern state as a supply base for militant republicanism. The Republic was undoubtedly a formidable logistics hinterland for such militants. However, criticisms of the reactions of authorities in the south are unfair. This article considers the explosives capabilities of the IRA during the first six years of their campaign. It does so with reference to their attempts to obtain commercial explosives as well as measures employed by them to obtain homemade explosives. The article also considers countermeasures employed by the southern government and reveals the extent to which they sought to shut down IRA capabilities in the south. It is argued that, ultimately, the IRA's campaign in this regard could only be contained and never unilaterally halted.     

INCOMPLETE ROHLFS–SULLIVAN ANALYSIS OF THE COST-EFFECTIVENESS OF ARMORED TACTICAL WHEELED VEHICLES FOR OVERSEAS US ARMY OPERATIONS

This comment addresses the Rohlfs–Sullivan analysis titled: ‘The Cost-Effectiveness of Armored Tactical Wheeled Vehicles [TWVs] for Overseas US Army Operations.’ The analysis evaluated policies to replace Type 1 and 2 TWVs with Type 3s. There is no evidence the analysis factored in fatality causes, fatality relationships to vehicles, or compared survivability of vehicles. Furthermore, it did not note when Type 3 TWVs were requested, when they impacted fatalities, or TWV use policies. It also assumed Type 3 TWVs prompted negative unit behaviors while discounting evidence of positive behaviors. In summary, the analysis is incomplete and should be revised.     

龙珍高级中学创建特色学校的探索与实践

创办特色学校是学生发展的需要,是学校生存与发展的需要,是学校个性化发展的需要。在由"学校特色"到"特色学校"这个复杂而曲折的发展过程中,理念创新是前提,坚持"普惠性"原则、着眼于学生群体素质的整体优化是本质,科学分析内外环境选定优势特色项目是关键,长期坚持注重量的积累是基础。龙珍高级中学顺应教育发展的需要,科学定位学校发展特色,遵循特色学校创建规律,全体师生广泛参与,积极探索和实践,使特色学校创建工作初见成效。     

Gas metal arc welding of high nitrogen stainless steel with Ar-N2-O2 ternary shielding gas

High nitrogen stainless steel with nitrogen content of 0.75％was welded by gas metal arc welding with Ar—N2-O2 ternary shielding gas. The effect of the ternary shielding gas on the retention and improvement of nitrogen content in the weld was identified. Surfacing test was conducted first to compare the ability of O2 and CO2 in prompting nitrogen dissolution. The nitrogen content of the surfacing metal with O2 is slightly higher than CO2. And then Ar—N2-O2 shielding gas was applied to weld high nitrogen stainless steel. After using N2-containing shielding gas, the nitrogen content of the weld was improved by 0.1 wt％. As N2 continued to increase, the increment of nitrogen content was not obvious, but the ferrite decreased from the top to the bottom. When the proportion of N2 reached 20％, a full austenitic weld was obtained and the tensile strength was improved by 8.7％. Combined with the results of surfacing test and welding test, it is concluded that the main effect of N2 is to inhibit the escape of nitrogen and suppress the ni-trogen diffusion from bottom to the top in the molten pool.