Factors Affecting the Processing of Epoxy Film Adhesives

The increasing awareness that adhesive performance is controlled not only by the condition of the adherend surface but also the condition or state of the adhesive and the process parameters used during fabrication is expected to result in improved reliability, as well as bond performance. The critical process variables which have been found to control adhesive bond formation and ultimate bond strength in 250F and 350F curing epoxy adhesives are described in terms of fabrication parameters and adhesive characteristics. These include the heat-up rate and cure temperature during processing and the adhesive moisture content and age condition (degree of advancement). The diagnostic methods used to delineate the effects of these process variables on adhesive performance are illustrated. These are dielectric, thermomechanical (TMA) and dynamic mechanical (DMA) analyses. Correlation of test results with measured mechanical tensile lap shear strengths of bonded joints is presented and the results briefly discussed in terms of the additives and hardeners used in the adhesive systems

Optimal coupling of entangled photons into single-mode optical fibers

We present a consistent multimode theory that describes the coupling of single photons generated by collinear Type-I parametric down-conversion into single-mode optical fibers. We have calculated an analytic expression for the fiber diameter which maximizes the pair photon count rate. For a given focal length and wavelength, a lower limit of the fiber diameter for satisfactory coupling is obtained

Virtual Consumption, Sustainability & Human Well-Being

There is widespread consensus that present patterns of consumption could lead to the permanent impossibility of maintaining those patterns and, perhaps, the existence of the human race. While many patterns of consumption qualify as ‘sustainable’ there is one in particular that deserves greater attention: virtual consumption. We argue that virtual consumption — the experience of authentic consumptive experiences replicated by alternative means — has the potential to reduce the deleterious consequences of real consumption by redirecting some consumptive behavior from shifting material states to shifting information states

Design, Fabrication and Test of Multi-Fiber Laminates

Unidirectional and angleply multifiber laminates were tested for improved impact strength and other mechanical properties. The effects of several variables on the mechanical properties of epoxy matrix materials were described. These include fiber type (HMS and AS graphites, glass, and Kevlar 49), ratio of primary to hybridizing fiber and hybrid configuration. It is demonstrated that AS graphite/S glass in an intraply configuration results in the best combination of static and Charpy impact properties as well as superior ballistic impact resistance. Pendulum impact tests which were conducted on thin specimens are shown to produce different ranking of materials than tests conducted on standard thickness Charpy specimens. It is shown that the thin specimen results are in better agreement with the ballistic impact data. Additional static test data are reported as a function of temperature for the seven best hybrid configurations having epoxy, polyimide (PMR-15) and polyphenylquinoxaline resins as the matrix

On a Possible Size/Color Relationship in the Kuiper Belt

Color measurements and albedo distributions introduce non-intuitive observational biases in size-color relationships among Kuiper Belt Objects (KBOs) that cannot be disentangled without a well characterized sample population with systematic photometry. Peixinho et al. report that the form of the KBO color distribution varies with absolute magnitude, H. However, Tegler et al. find that KBO color distributions are a property of object classification. We construct synthetic models of observed KBO colors based on two B-R color distribution scenarios: color distribution dependent on H magnitude (H-Model) and color distribution based on object classification (Class-Model). These synthetic B-R color distributions were modified to account for observational flux biases. We compare our synthetic B-R distributions to the observed 'Hot' and 'Cold' detected objects from the Canada-France Ecliptic Plane Survey and the Meudon Multicolor Survey. For both surveys, the Hot population color distribution rejects the H-Model, but is well described by the Class-Model. The Cold objects reject the H-Model, but the Class-Model (while not statistically rejected) also does not provide a compelling match for data. Although we formally reject models where the structure of the color distribution is a strong function of H magnitude, we also do not find that a simple dependence of color distribution on orbit classification is sufficient to describe the color distribution of classical KBOs

On the Localization of One-Photon States

Single photon states with arbitrarily fast asymptotic power-law fall-off of energy density and photodetection rate are explicitly constructed. This goes beyond the recently discovered tenth power-law of the Hellwarth-Nouchi photon which itself superseded the long-standing seventh power-law of the Amrein photon.Comment: 7 pages, tex, no figure

Factors influencing take-up of free school meals in primary- and secondary-school children in England.

OBJECTIVE: The present study sought to explore the factors that influence registration for free school meals and the subsequent take-up following registration in England. DESIGN: The research design consisted of two phases, a qualitative research phase followed by an intervention phase. Findings are presented from the qualitative research phase, which comprised interviews with head teachers, school administrators, parents and focus groups with pupils. SETTING: The study took place in four primary schools and four secondary schools in Leeds, UK. SUBJECTS: Participants included head teachers, school administrators, parents and pupils. RESULTS: Findings suggested that parents felt the registration process to be relatively straightforward although many secondary schools were not proactive in promoting free school meals. Quality and choice of food were regarded by both pupils and parents as significant in determining school meal choices, with stigma being less of an issue than originally anticipated. CONCLUSIONS: Schools should develop proactive approaches to promoting free school meals and attention should be given not only to the quality and availability of food, but also to the social, cultural and environmental aspects of dining. Processes to maintain pupils' anonymity should be considered to allay parents' fear of stigma

Evaluation of the energy transfer in the char zone during ablation. Part 2: In-depth response of ablative composites, volume 1

The decomposition of ablative composites is described along with the transport phenomena of pyrolysis gases which result from the decomposition of these plastics as they flow through the porous char of char-forming ablators. The pyrolysis products are those formed by the thermal degradation of nylon-phenolic resin and silicone elastomer composites. Emphasis is placed on the nature and extent of chemical reactions of the pyrolysis products and the char, along with the energy absorbed by the combined pyrolysis and char zone. Chemical reactions with thermodynamically consistent kinetic data are determined in order to develop a realistic analysis for predicting the thermal performance of ablative heat shields

Interventions to increase free school meal take-up

Purpose: The purpose of this paper is to design and implement interventions to increase free school meal (FSM) uptake in pilot schools. This paper describes the interventions, reports on acceptability (as perceived by school working parties) and explores the process of implementing change. Design/methodology/approach: The research consisted of two phases, an exploratory phase followed by an intervention phase. Findings from the latter are presented. Ten pilot schools (five primary and five secondary) in Leeds, England were recruited. Each established a working party, examined current claiming processes and implemented individualised action plans. This paper draws on the final action plans and interviews/focus groups with working parties. Findings: Interventions to improve FSM claiming process, minimise discrimination and maximise awareness were designed. The majority were implemented successfully, the exception being amending anti-bullying policies. Creative ways of delivering interventions were demonstrated. The process of change was effective, critical factors being having individualised action plans that allowed flexibility in implementation, reflecting on current claiming processes, and setting up working parties. Practical implications: Ways of working with schools to increase FSM uptake and more generally improve nutritional policies are suggested. Amending claiming systems in schools is recommended as is greater pupil and parent involvement in nutrition policies. Originality/value: An estimated 300,000 UK children do not take FSMs they are entitled to – with many schools unaware of the issue. This study worked with schools to discover how to address this issue and evaluated the perceived acceptability and feasibility of the approach

Tentative Detection of the Rotation of Eris

We report a multi-week sequence of B-band photometric measurements of the dwarf planet Eris using the {\it Swift} satellite. The use of an observatory in low-Earth orbit provides better temporal sampling than is available with a ground-based telescope. We find no compelling evidence for an unusually slow rotation period of multiple days, as has been suggested previously. A $\sim$1.08 day rotation period is marginally detected at a modest level of statistical confidence ($\sim$97%). Analysis of the combination of the $Swift$ data with the ground-based B-band measurements of \citet{2007AJ....133...26R} returns the same period ($\sim$1.08 day) at a slightly higher statistical confidence ($\sim$99%).Comment: Accepted to Icarus 2008-Aug-19. 19 pages total, including 4 figures and 1 tabl