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451.
Regardless of the outcome, civil wars are destructive events. They not only devastate the physical and human capital of a society, but also have a direct effect on state capacity. The capacity of the state is critical as it attempts to rebuild society and minimize the risk of a new civil conflict; yet, it is still not clear how civil war precisely affects state capacity. In general, we argue that incumbent victors are more likely to end with a stronger state when the conflict is short and the victory is decisive. In contrast, rebel victors require more time to build their internal capacity and thus have stronger states after a longer conflict, especially when they had access to lootable resources.  相似文献   
452.
Incorporating elastomers such as polymers in protective structures to withstand high energetic dynamic loads, has gained significant interest. The main objective of this study is to investigate the influence of a Polyurea coating towards the blast-induced response in steel plates. As such, Polyurea coated steel plates were tested under near-field blast loads, produced by the detonation of 1 kg of spherical nitromethane charges, at a standoff distance of 150 mm. Mild steel (XLERPLATE 350) and high-strength steel (BIS80) plates with thicknesses of 10 mm were Polyurea coated with thicknesses of 6 mm and 12 mm on either the front (facing the charge) or the back face. The deformation profiles were measured using 3D scanning. Numerical simulations were performed using the non-linear finite element code LS-DYNA. The strain-dependent behaviour of the steel and Polyurea were represented by Johnson-cook and Money-Rivlin constitutive models, respectively. The numerical models were validated by comparing the plate deflection results obtained from the experiments and were then used in the subsequent parametric study to investigate the optimum thickness of the Polyurea coating. The results indicate that back face coating contributes towards an approximately 20% reduction in the residual deformation as well as the absence of melting of the Polyurea layer, while the front-face coating can be used a means of providing additional standoff distance to the steel plates.  相似文献   
453.
This study investigates the ricochet behaviour of three different small-arms projectile types using a novel ricochet measuring device.The results can be used to estimate the danger potential of ricochets on shooting ranges.A ricochet is the change of direction and velocity of a projectile after impacting an oblique surface.This impact produces strong vibrations on a rigid plate.During this impact,flexural waves travel radially outwards from the point of impact.These waves are used to determine the properties of the impactor with accelerometers situated on the target surface.With the use of two measurement plates,one can produce a ricochet and detect the velocity at the same time.Accelerometers are suitable for accurate momentum measurements of single impacts.However,depending upon strike velocity and the impact angle,a ricochet can separate in multiple fragments after being deflected.From the operational safety perspective,these fragments need to be detected,as well.The approach of a coupled sensor concept was chosen to solve this problem.Thermographic sensors were additionally used to visualise the heat which is produced after pene-trating a rubber layer pasted in front of the steel target plate.With this approach one was able to detect the position of impact.The investigations showed that the measurement system performance is better with a multiple sensor design,which includes accelerometers for the velocity,impact strength and partly the position measurement,while the thermographic sensor was used for the position measurement and partly the momentum measurement.The investigated ammunition showed plausible fragmentation behaviour,and the results can already be used to estimate the danger potential of different ammunition types.Frangible projectiles fragment to small particles already after being deflected under a small angle.However,Full Metal Jacket projectiles with or without a steel core do not fragment under angles which are less than 5°.The objective of the paper is to demonstrate the possibility of measuring the complex ricochet me-chanics of small projectiles using standard accelerometers with the adequate signal processing approach.This measuring system is supported by an off the shelf thermographic camera.  相似文献   
454.
455.
ABSTRACT

The American way of war in Afghanistan presents a conundrum for proponents of 21st-century state-building projects. How can liberal peace proponents engage in efficient state building without sacrificing their ideals? The US learned that state-building allocates a degree of command and control to powerbrokers operating in the shadows to launder aid money, traffic illicit narcotics, and engage in extrajudicial punishments. These clients failed to represent the liberal values foreign patrons endorsed, because the latter not only offered resources without conditions but also rewarded bad behavior. This issue is examined by looking at the case of post-2001 northern Afghanistan, where powerful warlords should have held greater control over their paramilitary forces, limited predatory behavior, and built stronger relationships with the community. Instead, warlords-turned-statesmen expanded their material and social influence in the north, while holding onto the informal instruments of racketeering and patronage that overwhelmed Western ideals and shaped the predatory state present in Afghanistan today. Moreover, paramilitaries were influenced by material, social, and normative incentives that rewarded violent and predatory behavior and further eroded already weak community control mechanisms at the subdistrict level.  相似文献   
456.
457.
What do UK policymakers mean when they say that Britain’s strategic environment is returning to “multipolarity”? In realist international theory, polarity is a specific causal concept; the number of powers capable of balancing even the most capable other state(s) in the international system (“poles”) is taken to determine the system’s stability. Does the post-2017 appearance of polarity references in British security policy documents therefore reflect some unexpected UK renaissance of realist thought? Or is something else going on, as recent work by Ben Zala suggests? This article will demonstrate that, while UK official usage of the “multip–” word has indeed flourished recently, the term is actually being used in a more elastic, less bounded way than realism prescribes in order to generate other kinds of political effect. Specifically, “polarity” (and its “multi-” prefix) is used to characterise the behaviour of those major states that oppose Western-preferred international order, to elide Britain’s own relative power/status tensions, and to capture an expansive laundry-list of perceived international dangers. The article then discusses five ways in which a shift in polarity could negatively affect Britain; important consequences that merit preparatory contemplation, yet that an imprecise, catch-all understanding of “multipolarity” too readily obscures.  相似文献   
458.
ABSTRACT

Despite its portrayal as something new, the concept of the ‘gray zone’ is not novel. It was the Cold War battleground in which the USA and the Soviet Union waged rival unconventional campaigns, and it was there that the newly formed Central Intelligence Agency (CIA) was given responsibility for operating. This was not the organization’s original purpose, but Cold War exigencies forced Washington to improvise and build an organization with unique capabilities. These early years shaped the CIA’s operations directorate, creating two distinct cultures within the larger agency, one focused on intelligence collection and the other focused on covert action.  相似文献   
459.
ABSTRACT

Cyber attack against Critical National Infrastructure is a developing capability in state arsenals. The onset of this new instrument in national security has implications for conflict thresholds and military ethics. To serve as a legitimate tool of policy, cyber attack must operate in accordance with moral concerns. To test the viability of cyber attack, this paper provides a new perspective on cyber ethics. Cyber attack is tested against the criteria of the common good. This involves identifying the four core components of the common good from a conflict perspective: respect for the person; social wellbeing; peace and security; and solidarity. The fate of these components is assessed in relation to the six key characteristics of cyber attack from a moral standpoint: security; the role or absence of violence; discrimination; proportionality; cyberharm; and the threshold of conflict. It is concluded that the common good must be incorporated into developing state cyber strategies.  相似文献   
460.
ABSTRACT

Since 9/11, the United States has achieved notable gains against al Qaeda, and also Islamic State (IS), all while avoiding another mass-casualty attack at home. Yet, institutionally, culturally, and in its capabilities, the US government remains seriously ill-equipped for the task of countering irregular threats. Partly as a result, Islamist extremism shows no sign of being defeated, having instead metastasized since 9/11 and spread. Why, given the importance accorded to counterterrorism, has the US approach remained inadequate? What is impeding more fundamental reforms? The article evaluates the United States’ way of irregular warfare: its troubled engagement with counterinsurgency and its problematic search for lower cost and lower risk ways of combating terrorism. It suggests needed reforms but acknowledges also the unlikelihood of change.  相似文献   
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