Resilience to climate shocks in the tropics

This focus collection on resilience to climate shocks in the tropics draws together 16 papers that predominantly examine the impacts of, and responses to, the 2015/2016 El Niño-Southern Oscillation event, in a range of contexts. This introductory synthesis contextualises the collection of papers by reviewing important concepts and highlighting some important insights that emerge from the collection. The papers in this collection collectively highlight: the value of longitudinal and interdisciplinary research in understanding both the roots of, and responses to, resilience challenges; the critical interaction between climatic and land-use changes; and the ways in which governance arrangements underpin societal decision-making across a range of scales and contexts to shape resilience

Comparision of Density Measurement Methods for Unidirectional Flax-Epoxy Polymer Composites

Density is a decisive factor in determining one of the most important advantages of flax fiber-reinforced polymer (FFRP) composites, i.e. their relatively low weight leading to high specific properties. As a fundamental physical property of composites, density enters in many engineering design and quality control calculations and its value is a determining factor for several applications. Especially, we need precise material properties including density so as to develop efficient numerical models to these materials. In this work, three density measurement methods were evaluated and compared: Helium-gas pycnometry and Archimedes with two different immersing liquids, water and ethanol. The results show that Helium-gas pycnometry and Archimedes with ethanol gave similar and repeatable results, whereas using water resulted in much lower values. The density values were all in the range of reported values. However, Helium-gas pycnometry or Archimedes using ethanol are recommended for more precision in measuring the density of FFRP composites

Comparision of density measurement methods for unidirectional flax-epoxy polymer composites

Density is a decisive factor in determining one of the most important advantages of flax fiber-reinforced polymer (FFRP) composites, i.e. their relatively low weight leading to high specific properties. As a fundamental physical property of composites, density enters in many engineering design and quality control calculations and its value is a determining factor for several applications. Especially, we need precise material properties including density so as to develop efficient numerical models to these materials. In this work, three density measurement methods were evaluated and compared: Helium-gas pycnometry and Archimedes with two different immersing liquids, water and ethanol. The results show that Helium-gas pycnometry and Archimedes with ethanol gave similar and repeatable results, whereas using water resulted in much lower values. The density values were all in the range of reported values. However, Helium-gas pycnometry or Archimedes using ethanol are recommended for more precision in measuring the density of FFRP composites

The problem of mutually unbiased bases in dimension 6

We outline a discretization approach to determine the maximal number of mutually unbiased bases in dimension 6. We describe the basic ideas and introduce the most important definitions to tackle this famous open problem which has been open for the last 10 years. Some preliminary results are also listed

A Good Samaritan inspired foundation for a fair health care system

Distributive justice on the income and on the service aspects is the most vexing modern day problem for the creation and maintenance of an all inclusive health care system. A pervasive problem of all current schemes is the lack of effective cost control, which continues to result in increasing burdens for all public and private stakeholders. This proposal posits that the responsibility and financial obligation to achieve an ideal outcome of equal and affordable access and benefits for all citizens is misplaced. The Good Samaritan demonstrated basic ethical principles, which are revisited, elaborated and integrated into a new approach to health care. The participants are limited to individual contributors and beneficiaries and organized as a citizen carried, closed, independent, and self-sufficient self-governing cooperative for their own and the benefit of a minority of disadvantaged health care consumers. The government assumes oversight, provides arbitration, enforces democratic decision making, a scheme of progressive taxation, a separate and transparent accounting system, and a balance between income and reinvestment in health care. The results are a fair distribution of cost, its effective control, and increased individual motivation to take on responsibility for personal health as a private good and a sharpened focus towards community health. At the sociopolitical level the government as well as employers are released from the inappropriate burden of catering to individual health

Effect of machining parameters on the uncut fibers of a unidirectional flax fiber reinforced composite

In recent years, flax fiber-reinforced polymers (FFRP) are being widely used due to their inherent properties comparable to those of glass fiber reinforced polymers (GFRP). They are partially biodegradable and light weight with good intrinsic modulus and strength. However, milling these composites introduces defects like a poor surface quality with a lot of uncut fibers. The main objective of this study is to analyze the effect of machining parameters and fiber orientation on the uncut fibers (characterized by the number and length of the uncut fibers) of unidirectional FFRP. A full Split-Split Plot Block design of experiment approach was conducted for the analysis. It is shown that the uncut fibers extent depends significantly on the feed rate, the fiber orientation and the cutting tool geometry. The cutting speed does not influence the quantity of uncut fibers. A low feed rate (0.05 mm/rev) and a cutting tool geometry which enhances the fibers shear with a zero-helix angle are shown to minimize the delamination during the up-milling process of unidirectional flax/epoxy composite

Comparison between classical potentials and ab initio for silicon under large shear

The homogeneous shear of the {111} planes along the direction of bulk silicon has been investigated using ab initio techniques, to better understand the strain properties of both shuffle and glide set planes. Similar calculations have been done with three empirical potentials, Stillinger-Weber, Tersoff and EDIP, in order to find the one giving the best results under large shear strains. The generalized stacking fault energies have also been calculated with these potentials to complement this study. It turns out that the Stillinger-Weber potential better reproduces the ab initio results, for the smoothness and the amplitude of the energy variation as well as the localization of shear in the shuffle set

A Study of the interlaminar fracture toughness of unidirectional flax/epoxy composites

Having environmental and economic advantages, flax fibers have been recognized as a potential replacement for glass fibers as reinforcement in epoxy composites for various applications. Its widening applications require employing failure criteria and analysis methods for engineering design, analysis, and optimization of this material. Among different failure modes, delamination is known as one of the earliest ones in laminated composites and needs to be studied in detail. However, the delamination characteristics of unidirectional (UD) flax/epoxy composites in pure Mode I has rarely been addressed, while Mode II and Mixed-mode I/II have never been addressed before. This work studies and evaluates the interlaminar fracture toughness and delamination behavior of UD flax/epoxy composite under Mode I, Mode II, and Mixed-mode I/II loading. The composites were tested following corresponding ASTM standards and fulfilled all the requirements. The interlaminar fracture toughness of the composite were determined and validated based on the specific characteristics of natural fibers. Considering the variation in the composite structure configuration and its effects, the results of interlaminar fracture toughness fit in the range of those reported for similar composites in the literature and provide a basis for the material properties of this composite

The role of brand loyalty and social media in e-commerce interfaces: survey results and implications for user interfaces

This paper explores the role of brand loyalty and social media in e-commerce interfaces. A survey consisting of 118 respondents was contacted to address the questions relating to online shopping and brand loyalty. Link between the frequency of access and time spent on an e-commerce user interface, and brand loyalty, gender and age profile differences, and the role of social media to branding and on-line shopping was analyzed. It was found that online loyalty differs from offline loyalty and loyalty also differed across genders, showing men were more loyal than women when shopping online. Information shared about products on social media by friends and family played an important role in purchase decision making. Website interface and ease of navigation were also key aspects for online shopping. The research concluded with recommendations to create multimodal websites which are more interactive and targeted so customer experience is enhanced and loyalty is achieved through the use of interactivity and social media