Magnetic bearings-state of the art

Magnetic bearings have existed for many years, at least in theory. Earnshaw's theorem, formulated in 1842, concerns stability of magnetic suspensions, and states that not all axes of a bearing can be stable without some means of active control. In Beam's widely referenced experiments, a tiny (1/64 in diameter) rotor was rotated to the astonishing speed of 800,000 rps while it was suspended in a magnetic field. Despite a long history, magnetic bearings have only begun to see practical application since about 1980. The development that finally made magnetic bearings practical was solid state electronics, enabling power supplies and controls to be reduced in size to where they are now comparable in volume to the bearings themselves. An attempt is made to document the current (1991) state of the art of magnetic bearings. The referenced papers are large drawn from two conferences publications published in 1988 and 1990 respectively

Slippage Effects of the Conservation Reserve Program: New Evidence from Satellite Imagery

The Conservation Reserve Program (CRP) is the largest land retirement program ever operated in the US. Since its inception in 1985, many researchers have studied the impacts of this program; however, only a few have analyzed how the CRP affects surrounding non–enrolled parcels. In this research I examine how the CRP may affect the conversion of non–cropped land to agriculture, a phenomenon referred to as “slippage” in the literature, and specifically addressed by Wu (2000) and Roberts and Bucholtz (2005). Building on these earlier studies, I empirically model slippage using data derived from satellite imagery that provides information on land cover changes between 1992 and 2001. The study area consists of 1,053 counties located in the Northern Plains, Corn Belt and Lake States regions. Results support the existence of slippage effects from the CRP, but they are more conservative than the ones found by Wu (2000). The evidence of slippage provided here is important information for planners, given that whether and how the CRP affects land use decisions in surrounding areas is key information for implementing conservation efforts more efficiently.CRP, Land use change, Satellite imagery, Slippage effect, Agricultural and Food Policy, Land Economics/Use, Q15, Q24,

Experiments on dynamic stiffness and damping of tapered bore seals

Stiffness and damping were measured in tapered bore ring seals with air as the sealed fluid. Excitation was provided by a known unbalance in the shaft which rotated in the test seals. Results were obtained for various seal supply pressures, clearances, unbalance amounts, and shaft speeds. Stiffness and damping varied little with unbalance level, indicating linearity of the seal. Greater variation was observed with speed and particularly supply pressure. A one-dimensional analysis predicted stiffness fairly well, but considerably overestimated damping

The limits of deontology in dental ethics education

Most current dental ethics curricula use a deontological approach to biomedical and dental ethics that emphasizes adherence to duties and principles as properties that determine whether an act is ethical. But the actual ethical orientation of students is typically unknown. The purpose of the current study was to determine the ethical orientation of dental students in resolving clinical ethical dilemmas. First-year students from one school were invited to participate in an electronic survey that included eight vignettes featuring ethical conflicts common to the health care setting. The Multidimensional Ethics Scale was used to evaluate the students’ ethical judgments of these conflicts. Students rated each vignette along 13 ethically relevant items using a 7-point scale. Nine of the thirteen items were analyzed because they represent the dominant ethical theories, including deontology. One hundred sixteen dental students successfully completed the survey. Of the analyzed items, those associated with deontology had comparatively weak associations with whether students judged the action to be ethical and whether students judged themselves likely to perform the action. Whether an action was judged to be caring had the strongest association with whether the action was judged to be ethical and whether students judged themselves likely to perform the action. These results suggest that adherence to duties or principles has weaker association with students’ ethical judgments and behavior compared to caring, which was found to be more influential in their ethical judgments and behavior. Current dental school curricula with a primary focus on deontology may n

Virtual reality urban modelling - an overview

This paper offers an overview of the increasing use of Virtual Reality (VR) technologies for the simulation of urban environments. It provides a summary of cities worldwide where three-dimensional computer modelling is being utilised to aid urban planning. The study considers the need for a digital representation of cities and raises issues pertaining to advantages, barriers and ownership. A case study of a pilot project on the visualisation of Newcastle upon Tyne is examined to show an approach adopted for the representation of this city in North East England. The process of this visualisation is summarised and future research is outlined in relation to this city model

Enzymatic transhalogenation of dendritic RGD peptide constructs with the fluorinase

We thank EPSRC and the Scottish Imaging Network (SINAPSE) for grants. DO’H thanks the Royal Society for a Wolfson Research Merit Award and ST is grateful to the John and Kathleen Watson Scholarship for financial support. We are grateful to Dr Catherine Botting and Dr Sally Shirran of the St Andrews Mass Spectrometry Service for MALDI-MS acquisitions. We also thank Dr Sally Pimlott of the University of Glasgow for the use of radiochemistry facilities. Open access via RSC Gold for Gold.Peer reviewedPublisher PD

Making up for lost time: Forging new connections between health and community development

New trends in the today’s public health world are making an important case for bringing public health and community development efforts together. These include the changing nature of 21st century preventable disease, the increasing link between health disparities and place, and the early positive evidence from early adopters of combined health and development strategies. Read about specific examples of efforts from King County, Washington that are capitalizing on these changes and simultaneously advancing both health and community development.Community development ; Health

Angular Momentum on the Lattice: The Case of Non-Zero Linear Momentum

The irreducible representations (IRs) of the double cover of the Euclidean group with parity in three dimensions are subduced to the corresponding cubic space group. The reduction of these representations gives the mapping of continuum angular momentum states to the lattice in the case of non-zero linear momentum. The continuous states correspond to lattice states with the same momentum and continuum rotational quantum numbers decompose into those of the IRs of the little group of the momentum vector on the lattice. The inverse mapping indicates degeneracies that will appear between levels of different lattice IRs in the continuum limit, recovering the continuum angular momentum multiplets. An example of this inverse mapping is given for the case of the ``moving'' isotropic harmonic oscillator.Comment: v3) Little groups for lattice momenta corrected. Includes corrections from erratum submitted to Phys. Rev. D and a more consistent labeling scheme. v2) Minor changes to little groups. (9 pages

Animal Efficiency in an Intensive Beef Production System

A stochastic input distance function is estimated to analyse the efficiency with which physical characteristics of individual lot-fed beef cattle in Australia are combined with conventional inputs to produce a final product possessing defined quality attributes. High mean technical efficiency estimates are reported for all animals and by breed. All partial output elasticities with respect to inputs are of expected sign. Of four outputs included in the analysis, carcass weight and moisture retention in meat after cooking have highly significant coefficients of expected sign, but two meat quality variables have coefficients of unexpected sign indicating that they decline as inputs increase. Some evidence is detected of scope economies between moisture retention in meat and the inverse of meat compression.efficiency, intensive agriculture, scope economies, Livestock Production/Industries, Q12, C51,