Internal antiplasticisation in highly crosslinked amine cured multifunctional epoxy resins

The aromatic epoxy isomers triglycidyl p-aminophenol and triglycidyl m-aminophenol were cured with two aromatic diamine isomers 4,4′ diaminodiphenyl sulphone and 3,3′ diaminodiphenyl sulphone, creating four variations of epoxy resin. Dynamic and static mechanical analyses were used to understand the influence of chemical and network structure on the thermal, volumetric and mechanical properties of the epoxy resin. Fracture toughness increases are observed for networks containing meta substituted phenylene ring amines compared to the para equivalents, however no difference is noticed when the meta substituted phenylene ring epoxy is used. Use of meta substituted phenylene rings increases glassy modulus, yield stress, density and strain to failure. Correspondingly, decreases are seen in the glass transition temperature, intensity of the beta transition and the rubbery modulus. The results are entirely consistent with internal antiplasticisation caused by the presence of the meta substituted phenylene rings

Data from static and dynamic mechanical tests of different isomers of amine cured multifunctional epoxy resins

Data from gas pycnometry, static compressive stress-strain and dynamic mechanical analysis are presented for a series of aromatic amine cured epoxy resins. Samples are prepared and tested which consist of para-para, para-meta, meta-para and meta-meta isomers of the epoxy and amine phenylene ring respectively. The density data consists of 25 measurements on 3 separate samples of each of the 4 sample types. The static compressive stress–strain data consists of at least 5 tests on separate samples of each of the 4 samples types. The dynamic mechanical analysis data consists of multiple frequency, loss tangent measurements of at least 6 separate samples of each of the 4 sample types. The data is interpreted in the accompanying research article, ‘Internal antiplasticisation in highly crosslinked amine cured multifunctional epoxy resins

Statics and Dynamics of an Inhomogeneously-Nonlinear Lattice

We introduce an inhomogeneously-nonlinear Schr{\"o}dinger lattice, featuring a defocusing segment, a focusing segment and a transitional interface between the two. We illustrate that such inhomogeneous settings present vastly different dynamical behavior than the one expected in their homogeneous counterparts in the vicinity of the interface. We analyze the relevant stationary states, as well as their stability by means of perturbation theory and linear stability analysis. We find good agreement with the numerical findings in the vicinity of the anti-continuum limit. For larger values of the coupling, we follow the relevant branches numerically and show that they terminate at values of the coupling strength which are larger for more extended solutions. The dynamical development of relevant instabilities is also monitored in the case of unstable solutions.Comment: 14 pages, 4 figure

National and regional seasonal dynamics of all-cause and cause-specific mortality in the USA from 1980 to 2016

In temperate climates, winter deaths exceed summer ones. However, there is limited information on the timing and the relative magnitudes of maximum and minimum mortality, by local climate, age group, sex and medical cause of death. We used geo-coded mortality data and wavelets to analyse the seasonality of mortality by age group and sex from 1980 to 2016 in the USA and its subnational climatic regions. Death rates in men and women ≥ 45 years peaked in December to February and were lowest in June to August, driven by cardiorespiratory diseases and injuries. In these ages, percent difference in death rates between peak and minimum months did not vary across climate regions, nor changed from 1980 to 2016. Under five years, seasonality of all-cause mortality largely disappeared after the 1990s. In adolescents and young adults, especially in males, death rates peaked in June/July and were lowest in December/January, driven by injury deaths

Structured evaluation of virtual environments for special-needs education

This paper describes the development of a structured approach to evaluate experiential and communication virtual learning environments (VLEs) designed specifically for use in the education of children with severe learning difficulties at the Shepherd special needs school in Nottingham, UK. Constructivist learning theory was used as a basis for the production of an evaluation framework, used to evaluate the design of three VLEs and how they were used by students with respect to this learning theory. From an observational field study of student-teacher pairs using the VLEs, 18 behaviour categories were identified as relevant to five of the seven constructivist principles defined by Jonassen (1994). Analysis of student-teacher behaviour was used to provide support for, or against, the constructivist principles. The results show that the three VLEs meet the constructivist principles in very different ways and recommendations for design modifications are put forward

RIVERINE DISSOLVED ORGANIC MATTER DECOMPOSITION AND DYNAMICS

Aquatic and terrestrial ecosystems are intimately linked through the transfer of energy and materials. A common example of ecosystem linkage is the input of terrestrial dissolved organic matter (DOM) to rivers and streams. DOM can play a variety of roles in stream ecosystem function by fueling local food webs, influencing trophic state, and affecting the dissolved nutrient availability. Microorganisms utilize, transform, and produce DOM during microbial metabolism, a relationship that links microbes to DOM quality and quantity. Chemical and physical properties are known to vary with DOM source, and thus the type of terrestrial input may dictate how DOM is processed in a stream.  Using laboratory microcosms, and added terrestrial organic matter substrates, we carried out a leaching experiment over forty-five days. We employed a suite of complementary techniques to determine the effect of leaching DOM sources on microorganisms, DOM processing, and ecosystem function.  Microbial community composition changed from the original stream water inoculum and depended on DOM source. Cell abundances for all DOM sources spiked after two days, after which abundances dropped and remained relatively steady until the end of the experiment.  DOM concentrations decreased exponentially with the maximum amount of carbon utilization taking place within the first five days.  The DOM fluorescent signature, initially influenced by amino acid-like fluorescence shifts to more humic-like character over the course of the experiment, indicating DOM humification over time. Our results showcase the advantages of interdisciplinary tools to elucidate the connection of microbial processing, DOM chemistry, and ecosystem function

Social experience does not abolish cultural diversity in eye movements.

Adults from Eastern (e.g., China) and Western (e.g., USA) cultural groups display pronounced differences in a range of visual processing tasks. For example, the eye movement strategies used for information extraction during a variety of face processing tasks (e.g., identification and facial expressions of emotion categorization) differs across cultural groups. Currently, many of the differences reported in previous studies have asserted that culture itself is responsible for shaping the way we process visual information, yet this has never been directly investigated. In the current study, we assessed the relative contribution of genetic and cultural factors by testing face processing in a population of British Born Chinese adults using face recognition and expression classification tasks. Contrary to predictions made by the cultural differences framework, the majority of British Born Chinese adults deployed "Eastern" eye movement strategies, while approximately 25% of participants displayed "Western" strategies. Furthermore, the cultural eye movement strategies used by individuals were consistent across recognition and expression tasks. These findings suggest that "culture" alone cannot straightforwardly account for diversity in eye movement patterns. Instead a more complex understanding of how the environment and individual experiences can influence the mechanisms that govern visual processing is required

Biaxial strength characteristics of selected alloys in a cryogenic environment Final engineering report, 6 Jan. 1965 - 6 May 1966

Uniaxial and biaxial strength characteristics and mechanical properties of metallic sheet materials at cryogenic temperature