Three-dimensional omnidirectional acoustic illusion

Acoustic waves are ubiquitous in human everyday experience, therefore, precise control over the deformation of acoustic waves is always extremely desirable, which can be used, for example, to transform or hide objects from incident waves. Acoustic illusion devices are generally implemented by transformation acoustics, which can deceive ears or sonar systems. Challenges remain, the complexed and extreme material parameters prescribed by coordinate transformation theory make the implementations particularly difficult, even with the help of acoustic metamaterials. Here, a novel method based on Fabry-Perot resonances offers a feasible solution for achieve three-dimensional (3D) omnidirectional passive acoustic illusion. We theoretically demonstrated perfect 3D acoustic illusion via Mie theory, reduced version is further designed numerically and implemented experimentally. In the future, our work opens new possibilities for the implementation of modern acoustic illusion devices, such as camouflage for anti-sonar detection.

An Overall Uniformity Optimization Method of the Spherical Icosahedral Grid Based on the Optimal Transformation Theory

The improvement of overall uniformity and smoothness of spherical icosahedral grids, the basic framework of atmospheric models, is a key to reducing simulation errors. However, most of the existing grid optimization methods have optimized grid from different aspects and not improved overall uniformity and smoothness of grid at the same time, directly affecting the accuracy and stability of numerical simulation. Although a well-defined grid with more than 12 points cannot be constructed on a sphere, the area uniformity and the interval uniformity of the spherical grid can be traded off to enhance extremely the overall grid uniformity and smoothness. To solve this problem, an overall uniformity and smoothness optimization method of the spherical icosahedral grid is proposed based on the optimal transformation theory. The spherical cell decomposition method has been introduced to iteratively update the grid to minimize the spherical transportation cost, achieving an overall optimization of the spherical icosahedral grid. Experiments on the four optimized grids (the spring dynamics optimized grid, the Heikes and Randall optimized grid, the spherical centroidal Voronoi tessellations optimized grid and XU optimized grid) demonstrate that the grid area uniformity of our method has been raised by 22.60% of SPRG grid, −1.30% of HR grid, 38.30% of SCVT grid and 38.20% of XU grid, and the grid interval uniformity has been improved by 2.50% of SPRG grid, 2.80% of HR grid, 11.10% of SCVT grid and 11.00% of XU grid. Although the grid uniformity of the proposed method is similar with the HR grid, the smoothness of grid deformation has been enhanced by 79.32% of grid area and 24.07% of grid length. To some extent, the proposed method may be viewed as a novel optimization approach of the spherical icosahedral grid which can improve grid overall uniformity and smoothness of grid deformation.

Vortex dynamics and hydrodynamic performance enhancement mechanism in batoid fish oscillatory swimming

The effects of chordwise deformation and the half-amplitude asymmetry on the hydrodynamic performance and vortex dynamics of batoid fish have been numerically investigated, in which the two parameters were represented by the wavenumber ( $W$ ) and the ratio of the half-amplitude above the longitudinal axis to that below ( $HAR$ ). Fin kinematics were prescribed based on biological data. Simulations were conducted using the immersed boundary method. It was found that moderate chordwise deformation enhances the thrust, saves the power and increases the efficiency. A large $HAR$ can also increase thrust performance. By using the derivative-moment transformation theory at several subdomains to capture the local vortical structures and a force decomposition, it was shown that, at high Strouhal numbers ( $St$ ), the tip vortex is the main source of thrust, whereas the leading-edge vortex (LEV) and trailing-edge vortex weaken the thrust generation. However, at lower $St$ , the LEV would enhance the thrust. The least deformation ( $W=0$ ) leads to the largest effective angle of attack, and thus the strongest vortices. However, moderate deformation ( $W=0.4$ ) has an optimal balance between the performance enhancement and the opposite effect of different local structures. The performance enhancement of $HAR$ was also due to the increase of the vortical contributions. This work provides a new insight into the role of vortices and the force enhancement mechanism in aquatic swimming.

Transforming Congregational Conflict: An Integrated Framework for Understanding and Addressing conflict in Christian Faith Communities

<p>Churches have traditionally turned to conflict resolution measures, such as mediation, arbitration, and litigation, rather than conflict transformation approaches, when addressing congregational discord. In so doing, they miss the opportunity for constructive change that conflict presents and set themselves up for cycles of conflict to recur in the future. At the same time they diminish their self-claimed identity as followers of Jesus Christ, whose recorded teaching gives striking priority to peacemaking and reconciliation. Chapter one introduces the context for this thesis. Much work has already been done to explore biblical understandings of conflict, forgiveness and reconciliation, on the one hand, and to apply current conflict resolution practices to congregational settings on the other. However, little has been done to develop a conceptual framework that seeks to integrate biblical understandings with the insights of modern conflict analysis in a practically useful way. Chapter two of this thesis focuses on Jesus' teaching in Matthew 18 and shows why this passage is a key biblical resource for understanding and addressing congregational conflict. Chapter three examines conflict resolution theory and practice and shows why a transformational approach is the most appropriate one for addressing congregational conflict. The fourth chapter brings Jesus' teaching in Matthew 18 into a dialogue with current conflict transformation theory and practice. This conversation integrates theology and practice and clarifies the ways in which Jesus' teaching and transformative approaches to conflict both complement and enrich each other in the quest for lasting answers to the problem of congregational conflict. This thesis concludes by proposing a framework in which the many resources available might be understood and utilised in an integrated way by congregations that seek not only to enhance their capacity to respond to conflict in healthier ways, but also to embody the teachings of Christ in their midst.</p>

Transforming Congregational Conflict: An Integrated Framework for Understanding and Addressing conflict in Christian Faith Communities

<p>Churches have traditionally turned to conflict resolution measures, such as mediation, arbitration, and litigation, rather than conflict transformation approaches, when addressing congregational discord. In so doing, they miss the opportunity for constructive change that conflict presents and set themselves up for cycles of conflict to recur in the future. At the same time they diminish their self-claimed identity as followers of Jesus Christ, whose recorded teaching gives striking priority to peacemaking and reconciliation. Chapter one introduces the context for this thesis. Much work has already been done to explore biblical understandings of conflict, forgiveness and reconciliation, on the one hand, and to apply current conflict resolution practices to congregational settings on the other. However, little has been done to develop a conceptual framework that seeks to integrate biblical understandings with the insights of modern conflict analysis in a practically useful way. Chapter two of this thesis focuses on Jesus' teaching in Matthew 18 and shows why this passage is a key biblical resource for understanding and addressing congregational conflict. Chapter three examines conflict resolution theory and practice and shows why a transformational approach is the most appropriate one for addressing congregational conflict. The fourth chapter brings Jesus' teaching in Matthew 18 into a dialogue with current conflict transformation theory and practice. This conversation integrates theology and practice and clarifies the ways in which Jesus' teaching and transformative approaches to conflict both complement and enrich each other in the quest for lasting answers to the problem of congregational conflict. This thesis concludes by proposing a framework in which the many resources available might be understood and utilised in an integrated way by congregations that seek not only to enhance their capacity to respond to conflict in healthier ways, but also to embody the teachings of Christ in their midst.</p>

NON-STATE ACTOR IN CONFLICT TRANSFORMATION: MULTICULTURAL EDUCATION OF MA DAARUL ULUUM PUI MAJALENGKA TOWARDS ETHNO-RELIGION CONFLICT IN SOUTHERN THAILAND

The conflict between the Malay Muslim and the Thailand government in Southern Thailand has become one of the ethno-religion conflicts that effects the security of the Southeast Asian region. Various actors, both local and international, have attempted to broker peace between the parties in the conflict. Based on the conflict transformation theory, this study aims to discover the role of MA Daarul Uluum PUI Majalengka as a non-state actor in promoting peace through efforts of conflict transformation in the Southern Thailand ethno-religion conflict. The research method used is qualitative type research with descriptive analysis technique, through primary and secondary type data management. Primary data was obtained from interview and secondary data was obtained from written sources that support the study. This research shows there is an effort made by MA Daarul Uluum PUI Majalengka to conduct peace education through a student and teacher exchange scheme with several schools in Thailand that have Buddhist identity backgrounds in order to grow tolerance between ethnicities and religions in Thailand.

Transformation: From Sustainably Productive Agriculture to Industry?

The chapter explores issues of farm size, productivity, and structural transformation, as well as the reasons underlying performance. Productivity growth is crucial to structural transformation, and conventional wisdom held that small farms were more productive than large farms, in terms of yields per hectare. Increasingly, however, there is evidence that farms of all sizes can perform well, particularly when total factor productivity is measured in terms of all factors of production—that is, for farmers of large, medium, and small farms—rather than in terms of land productivity. Similarly, transformation theory has held that manufacturing tends to be more productive than agriculture, explaining migration from agriculture to industry and manufacturing being seen as the escalator of growth, but some evidence suggests agricultural productivity growth can be greater than growth of productivity in the manufacturing sector. Some have questioned the role of smallholder farms, suggesting development policy, particularly in sub-Saharan Africa, needs to foster medium and large farms, reallocating factors of production in their favor, as the only way to achieve an increase in overall levels of productivity and food for the burgeoning urban population. The chapter also tests the hypothesis of premature deindustrialization in many low-income and low-middle-income developing countries, including relative rates of growth in agriculture, manufacturing, and the service sector.