4,108 research outputs found
Thermodynamically stable lithium silicides and germanides from density-functional theory calculations
Density-functional-theory (DFT) calculations have been performed on the Li-Si
and Li-Ge systems. Lithiated Si and Ge, including their metastable phases, play
an important technological r\^ole as Li-ion battery (LIB) anodes. The
calculations comprise structural optimisations on crystal structures obtained
by swapping atomic species to Li-Si and Li-Ge from the X-Y structures in the
International Crystal Structure Database, where X={Li,Na,K,Rb,Cs} and
Y={Si,Ge,Sn,Pb}. To complement this at various Li-Si and Li-Ge stoichiometries,
ab initio random structure searching (AIRSS) was also performed. Between the
ground-state stoichiometries, including the recently found LiSi
phase, the average voltages were calculated, indicating that germanium may be a
safer alternative to silicon anodes in LIB, due to its higher lithium insertion
voltage. Calculations predict high-density LiSi and LiGe
layered phases which become the ground state above 2.5 and 5 GPa
respectively and reveal silicon and germanium's propensity to form dumbbells in
the LiSi, stoichiometry range. DFT predicts the stability of
the LiGe , LiGe and LiGe
phases and several new Li-Ge compounds, with stoichiometries LiGe,
LiGe, LiGe and LiGe.Comment: 10 pages, 5 figure
'Leaves and Eats Shoots': Direct Terrestrial Feeding Can Supplement Invasive Red Swamp Crayfish in Times of Need
PMCID: PMC3411828This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Footstep and Motion Planning in Semi-unstructured Environments Using Randomized Possibility Graphs
Traversing environments with arbitrary obstacles poses significant challenges
for bipedal robots. In some cases, whole body motions may be necessary to
maneuver around an obstacle, but most existing footstep planners can only
select from a discrete set of predetermined footstep actions; they are unable
to utilize the continuum of whole body motion that is truly available to the
robot platform. Existing motion planners that can utilize whole body motion
tend to struggle with the complexity of large-scale problems. We introduce a
planning method, called the "Randomized Possibility Graph", which uses
high-level approximations of constraint manifolds to rapidly explore the
"possibility" of actions, thereby allowing lower-level motion planners to be
utilized more efficiently. We demonstrate simulations of the method working in
a variety of semi-unstructured environments. In this context,
"semi-unstructured" means the walkable terrain is flat and even, but there are
arbitrary 3D obstacles throughout the environment which may need to be stepped
over or maneuvered around using whole body motions.Comment: Accepted by IEEE International Conference on Robotics and Automation
201
Honors Programs: Development, Review, and Revitalization
This is a monograph on the development and review of honors programs. Both subjects are treated in a single handbook because the materials presented here are useful in each process. The section on principles and practices of honors education in the United States (the overview) is background for those who would plan an honors program; for those who are reviewing and evaluating an existing program, the overview provides the means for educating those whose experience with honors is limited to the honors program of a single institution. It may add little or much to the director\u27s knowledge, but it is likely to broaden the perspectives of faculty and student members of an honors council, and of central administrators.
The self-study outline is based on the overview and provides an organizing pattern for the planning process as well as for the review of an existing program. When used by program planners, it should help with the assessment of the resources and readiness of the institution to host an honors program and should define the shape of the projected program; as a guide for the review of an existing program, it will suggest categories for review. When completed, the review document will furnish information for use by an outside consultant and by those within the institution who will be responsible for reshaping the program.
Since both the planning and review of honors programs often include the use of an outside consultant, a major section on making effective use of a consultant follows the self-study chapter.
Chapter four presents sample questions for the construction of survey instruments for gathering course, instructor and program evaluation from students, faculty, and alumni/ae and suggests patterns for the administration· of those instruments. The gathering and presentation of evaluative data take on special significance in times when the administrative watchword is accountability. Periodic program review is often mandated.
A proposed schedule for a visiting consultant is presented as Appendix A
Collaboration in Design:: A study of James B Hunt Jr. Library.
Collaborative design is a complex process that differs from the conventional system of sequential design by means of personal interaction, communication, and timing of design decisions. The complexity of the collaborative system, however, gives way to reduced cost and risk, increased project delivery speed, and improved building performance. As building projects become more complicated through technological advancements, and the architecture, engineering, and construction (AEC) practice embraces more integrated processes, it is important to understand the dynamics of collaborative design. Through the study of previous projects, intimate knowledge can be gained regarding partner interaction, oversights, team dynamics, processes, and benefits that are not always a part of a standardized list of collaborative benefits. This study will provide this insight by framing the design and construction of the James B. Hunt Jr. Library using a narrative case study format, beginning with designer selection and focusing on the collaborative aspects of the process. This transformative library is an example of innovation and success through collaboration. At many stages, the study of this project allows observes to gain insight into the the personal interaction between Snehetta and NCSU that enabled the project to be successful. This insight is provided through the review of construction and design documents, interviews of stakeholders and design professionals, and literature. The summary of the process will provide reviewers an example into how a collaborative process may differ from traditional methods, potential conflicts and understanding required for solution, and how collaborative design can benefit innovation and project success
Huggies, high-fives, and huismannen: Exploring the masculinity and everyday experiences of Dutch stay-at-home fathers
This qualitative research study explores Dutch stay-at-home fathers, or “huismannen,” and their everyday experiences with their role and their own masculinity. There has been much research conducted on stay-at-home fathers within other countries and cultures, but the current research significantly lacks the perspective and voices of those within the Dutch culture. To gather these voices, oral history interviews were conducted with five Dutch huismannen, and the collected data were analyzed using gender theory focused on masculinity and current relevant literature. This analysis led to the conclusion that Dutch stay-at-home fathers create and conform to a complicit masculine identity. It was also concluded that two characteristics of this complicit masculine identity, independence and societal membership, are threatened by stay-at-home fatherhood, but by participating in masculine engagements, these fathers managed to protect and maintain their independence, societal membership, and thus, their masculinity. Recommendations for future research conducted on this topic first includes a replication study with a larger sample size, and then includes a focus on generational differences and exploring the children and partner’s views of huismannen
The Collector As Arbiter Of Art A Phenomenological Investigation Of Collectors\u27 Critical Judgment Development And Their Understanding Of Art Toward A Theoretical Model For Appreciation And Criticism In Art Education
The purpose of this study was to investigate art collectors’ specific method of developing and making critical judgments in the context of their understanding of art. Phenomenological research methods were employed to obtain data through interviews with collectors of Contemporary African American art, Latin American art, and Minimalist and Conceptual art. Based on the findings, collectors’ approaches to critical judgment can be categorized into three areas. First, critical skills are both intuitive and developed over time, through a holistic and aesthetic process set in the art world. Collectors’ edification requires commitment, and intense looking enabling them to see how works of art communicate. Second, key events that marked collectors’ methodological approaches were connections with artists and art, notable purchases, and exhibitions of their collection. These events resulted from an integration of the collectors’ identification with the art work, manifested over time in various forms. Finally, those objects that best reflected collectors’ specific development of critical judgment and understanding of art were noted either by specific artists in their collection or the collection as a whole, functioning as vital aspects of the collectors’ life and at the same time contributing to culture and society in its capacity to cause conversations. There is an opportunity to apply the information from collectors’ processes as an educational model for teaching and learning about appreciation and criticism in art education by thinking about art collections more broadly, as another way to look at life and the art in life
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