Browsing by Subject "Structure"

Now showing 1 - 3 of 3

Open Access
Atomistic structure simulation of silicon nanocrystals driven with suboxide penalty energies
(American Scientific Publishers, 2008) Yılmaz, Dündar E.; Bulutay, Ceyhun; Çağın, T.
The structural control of silicon nanocrystals embedded in amorphous oxide is currently an important technological problem. In this work, an approach is presented to simulate the structural behavior of silicon nanocrystals embedded in amorphous oxide matrix based on simple valence force fields as described by Keating-type potentials. After generating an amorphous silicon-rich-oxide, its evolution towards an embedded nanocrystal is driven by the oxygen diffusion process implemented in the form of a Metropolis algorithm based on the suboxide penalty energies. However, it is observed that such an approach cannot satisfactorily reproduce the shape of annealed nanocrystals. As a remedy, the asphericity and surface-to-volume minimization constraints are imposed. With the aid of such a multilevel approach, realistic-sized silicon nanocrystals can be simulated. Prediction for the nanocrystal size at a chosen oxygen molar fraction matches reasonably well with the experimental data when the interface region is also accounted. The necessity for additional shape constraints suggests the use of more involved force fields including long-range forces as well as accommodating different chemical environments such as the double bonds.
Open Access
Transnational terrorism under structural realism
(2003) Sarı, Burcu
This thesis aims to analyze the concept of terrorism under the impact of international structure. For that purpose, first, the concept of terrorism is compared with other types of violence and its common characteristics were defined. Second, terrorism is classified and historical examples were given accordingly. Third, terrorist organizations were assessed as smart mechanisms that are able to learn and adapt into the conditions in which they subsist. Last, it is highlighted that in the development of terrorist organizations, besides their internal dynamics, states’ tendency to cheat plays a crucial role. Terrorist organizations make use of the feeling of uncertainty and grow stronger out of the states’ rivalry. In the end, they emerge as secondary actors. As units interacting in the international system, the behaviors of terrorist organizations are also shaped and shoved by the structure. They both affect and become subject to the impact of structure. The impacts of the new actor on the international system were evaluated according to the basic principles of Structural Realism. As a result, it is concluded that since structural factors plays a crucial role in the emergence of terrorism, as long as the structure endures, terrorism will also persist. Therefore, states should find ways to coexist with terrorism with the possible least hazard.
Open Access
Week-to-week interplay between teachers’ motivating style and students’ engagement
(Routledge, 2021-03-15) Michou, Aikaterini; Altan, Servet; Mouratidisa, Athanasios; Reeveb, J.; Malmbergc, L.
Research has shown that teachers’ autonomy support and provision of structure relate to students’ agentic and behavioral engagement. Moreover, agentic engagement elicits higher teacher autonomy support. In the present 5-week diary study, we investigated the dynamic nature of this interplay between teachers and students through their cross-assessment of students’ agentic and behavioral engagement. We also considered the week-to-week student-reported teacher autonomy support and provision of structure as well as two student personal characteristics — proactive personality and situational autonomous versus controlled motivation. Two hundred fifty-seven Turkish middle school students and their teachers from 13 classes participated in the study. Multilevel analyses showed that students’ week-to-week perceived autonomy support and initial level of autonomous motivation positively predicted week-to-week agentic engagement (teacher- and student-reported). Students’ week-to-week perceived structure positively predicted week-to-week agentic and behavioral engagement (student-, but not teacher-, reported). These findings indicate the interplay between students’ situational engagement and teachers’ situational motivating style (i.e., autonomy support and provision of structure). They also suggest greater predictive power for students’ situational motivation over the personal trait of proactive personality.