Key principles for user-centred systems design

The concept of user-centred systems design (UCSD) has no agreed upon definition. Consequently, there is a great variety in the ways it is applied, which may lead to poor quality and poor usability in the resulting systems, as well as misconceptions about the effectiveness of UCSD. The purpose of this paper is to propose a definition of UCSD. We have identified 12 key principles for the adoption of a user-centred development process, principles that are based on existing theory, as well as research in and experiences from a large number of software development projects. The initial set of principles were applied and evaluated in a case study and modified accordingly. These principles can be used to communicate the nature of UCSD, evaluate a development process or develop systems development processes that support a user-centred approach. We also suggest activity lists and some tools for applying UCSD.     

Surface wrinkling: the phenomenon causing bees in bitumen

The so called “bee phenomenon” in bitumen has been investigated by means of AFM quantitative nanomechanical property mapping. Bees are a phenomenon that can be observed by topography measurements using AFM. The characteristic “bee” appearance comes from regions with alternating higher and lower bands in the surface topography of bitumen, which are surrounded by a flat area. The proposed mechanism for bee formation is phase separation and differential contraction during cooling from melt temperatures leading to wrinkling due to differences in the elastic modulus of the material phases. Using a laminate wrinkling model, the thickness of the bee laminate was calculated from the wavelengths and Young’s moduli of the bee laminate and the matrix. It was found to vary between 70 and 140 nm for the five bitumen samples that contained significant amounts of wax.     

Carrot cropping on organic soil is a hotspot for nitrous oxide emissions

The emissions of the greenhouse gas nitrous oxide (N₂O) were measured from a non nitrogen fertilized carrot (Daucus carota ssp. sativa) field on an organic soil in Sweden during one cropping and post-harvest season. The cumulative emission during the measuring period of 149?days was 41 (±2.8) kg N₂O ha^?1. Dividing the measuring period into a cropping and a post-harvest period revealed that the presence of carrots strongly stimulated N₂O emissions, as the emission during the cropping period was one order of magnitude higher compared to the post-harvest period. The N₂O emission from the carrot field were higher than fluxes reported from cereal crop and grass production, but in the same order as reported fluxes from vegetable cropping on organic soils. In conclusion, our results indicate that the cultivation of root vegetable, such as carrots, on organic soil can be a high point source for N₂O emissions.     

Comparison of anodised aluminium surfaces from four fabrication methods

This study presents a comparative analysis of surface characteristics and properties of anodised aluminium cylinders produced by sand casting, permanent mould casting, extrusion, and high pressure die casting. Differences in micro structure and distribution of silicon particles in the aluminium, due to the fabrication method and the silicon content in the alloy, resulted in varying thickness of the oxide layers (mean thicknesses between 7 and 19 μm) and surface topography. The oxide layer was unevenly thick for the permanent mould cast and the sand cast cylinders, resulting in a surface with higher plateaus and lower areas. This was more prominent for the sand cast surface. The oxide of the extruded cylinder was thick and even and its surface was smooth. The high pressure die cast surface had an oxide that was very thin and uneven. The surfaces displayed different results in the scratch test due to the variations in the surface structure. For the permanent mould cast and the sand cast surfaces the silicon particles present in the oxide deflected the cracks that were formed during the scratching. This resulted in smaller wear debris. The nanohardness values of the oxides had a large scattering due to the inhomogeneous nature of the oxide layers, with pores and particles. However, the highest nanohardness values were between 5000 and 6000 MPa for the four surfaces, which is significantly lower than that of sintered alumina. In the micro abrasion test the wear mechanism for all four surfaces was microcutting resulting in chippings.     

Characterization of a water-based paint for corrosion protection

Corrosion of steel rebars in reinforced concrete is one of the major problems in the construction industry. Carbonation reactions of concrete with carbon dioxide and, mainly, the chloride salts action are the main causes responsible for concrete degradation. Protective coatings help to improve the durability of concrete structures by acting as a physical barrier against the corrosion agents. Waterborne paints are usually used for concrete protection rather than solvent-based paints since they are less pollutant. The aim of this work is to investigate the influence of the pore size and porosity on the permeability of the paints films toward sodium chloride. Three characterization methods from membrane science were implemented to characterize paint coatings. The time-lag method was used to determine the permeability toward the sodium chloride and toward helium and argon, these for approximately 100% relative humidity. From the seven waterborne paints formulated, only one was found to be suitable for surface protection of reinforced concrete, since its permeability toward NaCl was smaller than 10⁻¹⁴ m² s⁻¹, the threshold value required by National Laboratory of Civil Engineering (LNEC) in Portugal. For the formulated paints, it was observed that the average pore size correlates well with the permeability toward sodium chloride. This is an important result since obtaining the permeability toward sodium chloride of corrosion protective paints is very time consuming, while the average pore size can be obtained in a much shorter time.     

The effect of co-encapsulation of Lactobacillus rhamnosus GG ATCC 53103 with inulin on alginate/chitosan matrix: the viability in fermented soy blend and simulated digestive system

This research verified the ability of Lactobacillus rhamnosus encapsulated with inulin to tolerate the simulated digestive system and their viability in a soy blend. Probiotic encapsulated in alginate-chitosan matrix without inulin presented a better encapsulation efficiency (80.92%) than encapsulation with inulin (57.39%). On the 28th day, the count of probiotics decreased by 3.42 and 1.99 logarithmic cycles of free and encapsulated cells without inulin, respectively. In contrast, the microorganisms encapsulated with inulin showed an increase of 1.26 logs CFU g⁻¹. During gastrointestinal simulation, cell counts decreased by 0.78, 1.55 and 1.95 CFU g⁻¹ logs for encapsulated cells without inulin, free and encapsulated with inulin, respectively. Sensory panellists liked the fermented soy blend with encapsulated lactobacilli, and this result shows the possibility to create new probiotic foods of plant origin. Therefore, the alginate/chitosan matrix can be considered adequate for the encapsulation of L. rhamnosus. The inulin reduces the encapsulation efficiency and increases the cell loss in gastrointestinal simulation. Considering cellular losses, the best option for preparing a fermented soy blend is to use L. rhamnosus encapsulated without inulin.     

The compressibility and compactibility of different types of lactose

Objective: The purpose of this study was to investigate and quantify flow properties, compressibility, and compactibility of various pharmaceutical lactose powders found on the market today (DCL-11, DCL-21, M‐200, Flowlac-100, and Tablettose 70, 80, and 100). Methods: Flow properties were estimated by measuring flow time, angle of repose, and the Hausner ratio. Particle rearrangement was studied using Kawakita's linear model. Compressibility was studied using two ‘out-of-die’ methods: (i) the Heckel model and (ii) a modified Walker model. Compactibility was quantified using two methods: (i) the tensile strength profile (Cp) and (ii) the compactibility factor (Pr). Statistical approach was used to analyze the results. Results: Flow properties of all materials were passable or better, except for M-200, which has very poor flowability. Compressibility results demonstrated that the most compressible lactose is spray-dried grade of lactose (Flowlac-100) and the least compressible is milled lactose (M-200). Compactibility studies showed that β‐lactose (DCL-21) forms tablets with superior tensile strength in comparison with α-lactose. Conclusion: Results of the compressibility study showed that the discriminative power of modified Walker model is greater in comparison with Heckel model. Compactibility methods yield similar and comparable results.     

The Difficulties of Designing Future Coastlines in the Face of Climate Change

This paper adopts two perspectives. The first is a framing process aimed at defining and examining the conditions for adopting adaptive coastal governance. The second applies to relevant themes of changing coastal policy, central to the testing of adaptive coastal governance, namely cooperative science, risk-sensitive planning, socially fair insurance cover and effective ways to design, finance and engage with local communities over actual coastal change. We illuminate both missions through case studies in North Norfolk (England) and Portugal, all notably affected by coastal change. In England and Portugal, there is a broad understanding and acceptance of the likely effects of climate change. This recognition encourages debates over risk-averse planning, the design of proactive insurance cover, creative relocation of endangered property and new ways of predicting and paying for coastal adjustment. Yet, moving from a basic willingness to engage with coastal change to actual practices of landscape adjustment through such policy shifts is proving very difficult. In this research, we find that coastal landscapes are lived experiences, resigned acceptances of inevitable change and hopeful imaginings. Coastal management institutions are not geared to resolving this incompatibility and this paper explains why.     

New urban forms: the crescents of Bath and Le Corbusier's plan for Rio de Janeiro

This article considers whether formal references in Le Corbusier's work may be traced to the eigtheenth century crescents of Bath and, in particular, Lansdowne Crescent. By exploring this line, it raises the possibility that in the work he produced for the Latin American context, this arch-modernist planner moved beyond the de-contextualized approach for which he is known and explored the possibility of integrating new urban forms with nature. The article also shows how Le Corbusier's plans for Rio de Janeiro allowed him to become an important formal reference point for successive generations of local architects and planners.