Developing strategies to toughen bio-inspired adhesives

Mussels and other marine creatures adhere very well in underwater environments, having the ability to withstand the force of the sea. These animals have inspired synthetic biomimetic adhesives for wet systems, presenting potential for biomedical applications. However, most current commercial adhesives tend to be brittle, not resisting repetitive movements. This study assesses toughening strategies to improve the mussel-inspired adhesives’ ductility while maintaining its strength. The strategies included altering the polymer’s chemical structure by changing the percentage of polyethylene glycol (PEG) in the molecule and by adding fillers, such as calcium carbonate, silica and nacre - a calcium carbonate compound found in shells. The dry adhesion of the glues was tested by shear lap tests on standard aluminum samples. The addition of PEG increased the ductility of the polymer considerably, creating a viscous paste rather than a solid. Future advances include analyzing the tensile strength and adhesion of the systems, as well as their resistance in wet environments. Furthermore, the toxicity of both the polymer and potential fillers should be investigated

Who punishes the leader? Leader culpability and coups during civil war

Who punishes leaders via coups during civil war? By distinguishing between different types of internal audiences within the government and their attempts to remove a leader forcefully, I illuminate the mechanisms that explain variation in who punishes the leader during wartime. I claim that whether leaders are culpable for the initiation of the war has an important implication for whether they are punished by members of the ruling coalition (i.e., those with access to decision-making and political power), or by those outside the ruling coalition. Empirical evidence supports my hypotheses: (i) culpable leaders are more likely to experience coup attempts led by those outside the leaders' ruling coalition, should the war go poorly; and (ii) nonculpable leaders are more likely to experience coups executed by members of their ruling coalition. The findings have important implications for how leaders respond to audience pressures as they consider whether to fight or settle

The Strategic Shuffle: Ethnic Geography, the Internal Security Apparatus, and Elections in Kenya

For autocrats facing elections, officers in the internal security apparatus play a crucial role by engaging in coercion on behalf of the incumbent. Yet reliance on these officers introduces a principal‐agent problem: Officers can shirk from the autocrat’s demands. To solve this problem, autocrats strategically post officers to different areas based on an area’s importance to the election and the expected loyalty of an individual officer, which is a function of the officer’s expected benefits from the president winning reelection. Using a data set of 8,000 local security appointments within Kenya in the 1990s, one of the first of its kind for any autocracy, I find that the president’s coethnic officers were sent to, and the opposition’s coethnic officers were kept away from, swing areas. This article demonstrates how state institutions from a country’s previous authoritarian regime can persist despite the introduction of multi‐party elections and thus prevent full democratization.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136510/1/ajps12279_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136510/2/ajps12279.pd

Writ(h)ing Images: Imagination, the Human Form, and the Divine in William Blake, Salman Rushdie, and Simon Louvish

In this paper, we address issues in segmentation Of remotely sensed LIDAR (LIght Detection And Ranging) data. The LIDAR data, which were captured by airborne laser scanner, contain 2.5 dimensional (2.5D) terrain surface height information, e.g. houses, vegetation, flat field, river, basin, etc. Our aim in this paper is to segment ground (flat field)from non-ground (houses and high vegetation) in hilly urban areas. By projecting the 2.5D data onto a surface, we obtain a texture map as a grey-level image. Based on the image, Gabor wavelet filters are applied to generate Gabor wavelet features. These features are then grouped into various windows. Among these windows, a combination of their first and second order of statistics is used as a measure to determine the surface properties. The test results have shown that ground areas can successfully be segmented from LIDAR data. Most buildings and high vegetation can be detected. In addition, Gabor wavelet transform can partially remove hill or slope effects in the original data by tuning Gabor parameters

Explaining Myanmar's Regime Transition: The Periphery is Central

In 2010, Myanmar (Burma) held its first elections after 22 years of direct military rule. Few compelling explanations for this regime transition have emerged. This article critiques popular accounts and potential explanations generated by theories of authoritarian ‘regime breakdown’ and ‘regime maintenance’. It returns instead to the classical literature on military intervention and withdrawal. Military regimes, when not terminated by internal factionalism or external unrest, typically liberalise once they feel they have sufficiently addressed the crises that prompted their seizure of power. This was the case in Myanmar. The military intervened for fear that political unrest and ethnic-minority separatist insurgencies would destroy Myanmar’s always-fragile territorial integrity and sovereignty. Far from suddenly liberalising in 2010, the regime sought to create a ‘disciplined democracy’ to safeguard its preferred social and political order twice before, but was thwarted by societal opposition. Its success in 2010 stemmed from a strategy of coercive state-building and economic incorporation via ‘ceasefire capitalism’, which weakened and co-opted much of the opposition. Having altered the balance of forces in its favour, the regime felt sufficiently confident to impose its preferred settlement. However, the transition neither reflected total ‘victory’ for the military nor secured a genuine or lasting peace

Strong armies, slow adaptation: civil-military relations and diffusion of military power

Why are some states more willing to adopt military innovations than others? Why, for example, were the great powers of Europe able to successfully reform their military practices to better adapt to and participate in the so-called military revolution of the sixteenth and seventeenth centuries while their most important extra-European competitor, the Ottoman Empire, failed to do so? This puzzle is best explained by two factors: civil-military relations and historical timing. In the Ottoman Empire, the emergence of an institutionally strong and internally cohesive army during the early stages of state formation—in the late fourteenth century—equipped the military with substantial bargaining powers. In contrast, the great powers of Europe drew heavily on private providers of military power during the military revolution and developed similar armies only by the second half of the seventeenth century, limiting the bargaining leverage of European militaries over their rulers. In essence, the Ottoman standing army was able to block reform efforts that it believed challenged its parochial interests. Absent a similar institutional challenge, European rulers initiated military reforms and motivated officers and military entrepreneurs to participate in the ongoing military revolution

Jumping on the Bandwagon: Differentiation and Security Defection during Conflict

When confronted with mass uprisings, governments deploy their security forces for crowd control or repression. However, sometimes security agencies choose to side with the opposition movement. Recent work shows that “fragmentation” contributes to defection: fragmenting the security forces into parallel units leads to oversight problems and grievances among soldiers, which raises the risk of members of the security forces defecting to the opposition movement. However, I argue that the effect on defection is strongly moderated by the circumstances under which states choose to fragment their military: fragmentation for the purpose of security specialization, called “differentiation,” even decreases its risk. Employing Bayesian multilevel modeling, the findings corroborate this distinction. The study contributes to the fundamental discussion on civil–military relations, shedding light on why some conflict situations see security defections while others do not. Understanding this phenomenon is a pivotal element to explaining how conflicts develop, escalate, and end