A Highly Flexible Bunch Compressor for the APS LEUTL FEL

The LEUTL FEL at the APS has achieved gain at 530 nm with peak beam current \~100 A. In an effort to push to 120 nm and beyond, we have designed and are commissioning a bunch compressor to increase the peak current to 600 A or more. The bunch compressor uses a four-dipole chicane at an energy of 100 to 210 MeV. To provide options for control of emittance growth due to coherent synchrotron radiation (CSR), the chicane has variable R56. The central pair of dipoles is movable, accommodating variable R56 with less concern about emittance dilution from nonuniformity of the dipole field. The symmetry of the chicane is also variable via longitudinal motion of the final dipole, which is predicted to have an effect on emittance growth. Following the chicane, a three-screen emittance measurement system should permit resolution of the difference in emittance growth between various chicane configurations. A vertical bending magnet analysis line is present to permit imaging of correlations between transverse and energy coordinates. This paper reviews the features and expected performance of the chicane. A companion paper discusses the physics design in detail. Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.Comment: LINAC2000 THC05 3 pages 1 figur

STRUCTURAL CHANGE IN U.S. CHICKEN AND TURKEY SLAUGHTER

Cost function analyses using data from the U.S. Bureau of the Census reveal substantial scale economies in chicken and turkey slaughter. These economies show no evidence of diminishing as plant size increases, are much greater than those realized in cattle and hog slaughter, and have resulted in a huge increase in plant size over the 1972-92 period. The findings also suggest that consolidation in the chicken and turkey slaughter industry is likely to continue, particularly if the growth in the demand for poultry diminishes.chicken slaughter, turkey slaughter, production costs, structural change, Livestock Production/Industries,

Autism: Understanding Behaviour

Being a parent is a demanding role. It places demands on our tolerance, our time, our energy levels, our coping skills and our physical stamina. But in the end the large majority of us consider that the attachments we form with our children, the pleasure they give us, the opportunities to contribute to their lives and the affection we receive back is all worth it. From the moment of our child's birth we attune to their movement and vocalisation, and in the dance of interaction we hope they attune to us. As our daughters and sons develop, we observe changes in the nature of our interactions. Development necessitates changes in bodies and minds, and so we adapt our own expectations and anticipation of our child’s behaviour to retain synchronicity and share common experience. The changes in our engagements reflect the development in reaching common milestones in the nature of parent-child interaction, primarily initiated by the anticipated development of the child. Ultimately, we expect that our children will become adults and each family may have a set of expectations that may or may not be reached. For a range of cultural, ethical and legal reasons, our children generally become adults in their own right at the age of 16, but it should be remembered that they never stop being our sons and daughters, and the bonds developed in childhood are equally as strong when our children become adults. Most of us cope well with the demands our children make of us, although we can feel an overwhelming sensation of frustration from time to time. However, some of us find it difficult to cope at times. Irrespective of disability, some parents are just more able to cope than others, and from time to time all of us need help, whether it be from family members, friends or outside agencies. Parents of autistic children are no different in their coping resources than any other parent, but they can be faced by a range of what they may see as confusing behaviour from their child that can alter how they engage. For some families this can place unanticipated demands, create challenging situations and stress within parent-child interactions, particularly when in public settings where the stakes are high and social cost significant. This chapter discusses the demands placed on parent-child interactions. It aims to provide some guidance as to how to derive meaning through interaction and offer some tips and strategies that will facilitate engagement. While this chapter is primarily aimed at parents and carers of autistic children as well as practitioners working with autistic children, not all of the information or strategies will be relevant or appropriate for a particular child. Each person and situation is unique, so it’s important to think about how the issues discussed here relate to your own context

A Quantitative Analysis of the Fusion of 3-D Scanning LIDAR Systems and 2-D Imaging Systems

This research will demonstrate the feasibility of fusing the superior spatial resolution of a 2-D imaging system with the precise range to target information of a 3-D imaging system to create a LIDAR imaging system that can accurately find what and where a target is. The 3-D imaging system will use a scanning method as opposed to a flash method that has been used in similar research. The goal of this research is to improve performance of scanning LIDAR so it has better spatial resolution. The research in this thesis proves that incorporating 2-D imaging data into 3-D scanning LIDAR data improves the spatial resolution of the LIDAR system, at least for simplistic environments. This idea is introduced to improve LIDAR systems for missile seekers. Incorporating this system in missile seekers will allow improved target tracking compared to a 3-D scanning system alone

On three-dimensional dilational elastic metamaterials

Dilational materials are stable three-dimensional isotropic auxetics with an ultimate Poisson's ratio of -1. We design, evaluate, fabricate, and characterize crystalline metamaterials approaching this ideal. To reveal all modes, we calculate the phonon band structures. On this basis, using cubic symmetry, we can unambiguously retrieve all different non-zero elements of the rank-4 effective metamaterial elasticity tensor, from which all effective elastic metamaterial properties follow. While the elastic properties and the phase velocity remain anisotropic, the effective Poisson's ratio indeed becomes isotropic and approaches -1 in the limit of small internal connections. This finding is also supported by independent static continuum-mechanics calculations. In static experiments on macroscopic polymer structures fabricated by three-dimensional printing, we measure Poisson's ratios as low as -0.8 in good agreement with theory. Microscopic samples are also presented.Comment: 8 figure