Prediction intervals for reliability growth models with small sample sizes

Engineers and practitioners contribute to society through their ability to apply basic scientific principles to real problems in an effective and efficient manner. They must collect data to test their products every day as part of the design and testing process and also after the product or process has been rolled out to monitor its effectiveness. Model building, data collection, data analysis and data interpretation form the core of sound engineering practice.After the data has been gathered the engineer must be able to sift them and interpret them correctly so that meaning can be exposed from a mass of undifferentiated numbers or facts. To do this he or she must be familiar with the fundamental concepts of correlation, uncertainty, variability and risk in the face of uncertainty. In today's global and highly competitive environment, continuous improvement in the processes and products of any field of engineering is essential for survival. Many organisations have shown that the first step to continuous improvement is to integrate the widespread use of statistics and basic data analysis into the manufacturing development process as well as into the day-to-day business decisions taken in regard to engineering processes.The Springer Handbook of Engineering Statistics gathers together the full range of statistical techniques required by engineers from all fields to gain sensible statistical feedback on how their processes or products are functioning and to give them realistic predictions of how these could be improved

Deposit-Refund Systems in Practice and Theory

A deposit-refund system combines a tax on product consumption with a rebate when the product or its packaging is returned for recycling. Deposit-refunds are used for beverage containers, lead-acid batteries, motor oil, tires, various hazardous materials, electronics, and more. In addition, researchers have shown that the approach can be used to address many other environmental problems beyond waste disposal. By imposing an up-front fee on consumption and subsidizing “green” inputs and mitigation activities, a deposit-refund may be able to efficiently control pollution in much the same way as a Pigovian tax. Theoretical models have shown that alternative waste disposal policies, such as virgin materials taxes, advance disposal fees, recycled content standards, and recycling subsidies are inferior to a deposit-refund. These results have been corroborated in calibrated models of U.S. waste and recycling. And in theoretical models that consider joint environmental problems and product design considerations, the deposit-refund continues to have much to recommend it as a component of an overall socially optimal set of policies. More empirical research into deposit-refund systems is needed, particularly the upstream systems used for many products. In these systems, the processors or collectors of recyclables—rather than consumers—receive the refund. Upstream systems may have lower transaction costs and better environmental outcomes than traditional downstream systems.deposit-refund, waste disposal, recycling, source reduction, illegal dumping, Pigovian tax, advance disposal fee, upstream pollution, design for environment

Domain walls within domain walls in wide ferromagnetic strips

We carry out large-scale micromagnetic simulations which demonstrate that due to topological constraints, internal domain walls (Bloch lines) within extended domain walls are more robust than domain walls in nanowires. Thus, the possibility of spintronics applications based on their motion channeled along domain walls emerges. Internal domain walls are nucleated within domain walls in perpendicularly magnetized media concurrent with a Walker breakdown-like abrupt reduction of the domain wall velocity above a threshold driving force, and may also be generated within pinned, localized domain walls. We observe fast field and current driven internal domain wall dynamics without a Walker breakdown along pinned domain walls, originating from topological protection of the internal domain wall structure due to the surrounding out-of-plane domains.Comment: 5 pages, 6 figure

Rings associated to coverings of finite p-groups

In general the endomorphisms of a non-abelian group do not form a ring under the operations of addition and composition of functions. Several papers have dealt with the ring of functions defined on a group which are endomorphisms when restricted to the elements of a cover of the group by abelian subgroups. We give an algorithm which allows us to determine the elements of the ring of functions of a finite $p$-group which arises in this manner when the elements of the cover are required to be either cyclic or elementary abelian of rank $2$. This enables us to determine the actual structure of such a ring as a subdirect product. A key part of the argument is the construction of a graph whose vertices are the subgroups of order $p$ and whose edges are determined by the covering.Comment: 11 pages. No figures. To appear Turkish Journal of Mathematic

Domain walls of ferroelectric BaTiO3 within the Ginzburg-Landau-Devonshire phenomenological model

Mechanically compatible and electrically neutral domain walls in tetragonal, orthorhombic and rhombohedral ferroelectric phases of BaTiO3 are systematically investigated in the framework of the phenomenological Ginzburg-Landau-Devonshire (GLD) model with parameters of Ref. [Hlinka and Marton, Phys. Rev. 74, 104104 (2006)]. Polarization and strain profiles within domain walls are calculated numerically and within an approximation leading to the quasi-one-dimensional analytic solutions applied previously to the ferroelectric walls of the tetragonal phase [W. Cao and L.E. Cross, Phys. Rev. 44, 5 (1991)]. Domain wall thicknesses and energy densities are estimated for all mechanically compatible and electrically neutral domain wall species in the entire temperature range of ferroelectric phases. The model suggests that the lowest energy walls in the orthorhombic phase of BaTiO3 are the 90-degree and 60-degree walls. In the rhombohedral phase, the lowest energy walls are the 71-degree and 109-degree walls. All these ferroelastic walls have thickness below 1 nm except for the 90-degree wall in the tetragonal phase and the 60-degree S-wall in the orthorhombic phase, for which the larger thickness of the order of 5 nm was found. The antiparallel walls of the rhombohedral phase have largest energy and thus they are unlikely to occur. The calculation indicates that the lowest energy structure of the 109-degree wall and few other domain walls in the orthorhombic and rhombohedral phases resemble Bloch-like walls known from magnetism.Comment: 12 pages, 9 figure

Affirmational and Transformational Values and Practices in the Tolkien Fanfiction Community

Fanfiction based on the legendarium of J.R.R. Tolkien has existed for at least six decades and has been, within the past two, one of the most consistently active online fanfiction communities. Despite this, the fandom has been relatively unstudied by fan studies scholars. This paper considers how Tolkien-based fanfiction corroborates and complicates current theories of fanfiction, focusing especially on a theory proposed by obsession_inc that proposes two types of fandoms: affirmational and transformational. Current thought places fanfiction at the transformational end of the continuum. Using quantitative survey data of authors and readers of Tolkien-based fanfiction, this paper offers evidence that Tolkien-based fanfiction contains significant affirmational components that are an intentional and valued part of many Tolkien fanfiction communities. Authors and readers regard authority, critical functions of fanfiction, and reparative purposes for fanfiction differently than the more commonly studied media fandoms. Yet one cannot say simply that authors of Tolkien-based fanfiction are more affirmational than other fanwriters; instead, evidence shows that authors and readers of Tolkien-based fanfiction navigate transformational and affirmational elements in complex ways, and community cultures often center upon members’ values and practices