Environmental evaluation of localising production as a strategy for sustainable development: a case study of two consumer goods in Jamaica

The objective of this study was to compare the life-cycle environmental impacts of changed production structures for two consumer goods (high-density polyethylene (HDPE) shopping bags and beds) in Jamaica. A scenario technique was used to construct three alternative production structures for each product; each scenario reflecting an increase in local production in Jamaica which depended on an increased supply of input materials which may be sourced: (1) externally from overseas suppliers, (2) from post-consumer recycling, and (3) locally on the island of Jamaica. These three constructed scenarios were then compared to the existing supply chain or reference scenarios of the products. The results showed that for both case products the recycling scenario was most preferable for localising production, resulting in the lowest environmental impact. This was because the production of raw materials accounted for the largest effect on total environmental impact. As such, the most immediate environmental improvements were realised by lowering the production of virgin materials. © 2007 Elsevier Ltd. All rights reserved.

The production of separate streams of pure hydrogen and carbon dioxide from coal via an iron-oxide redox cycle

A chemical looping process using the redox reactions of iron oxide has been used to produce separate streams of pure H2 and CO2 from a solid fuel. An iron oxide carrier prepared using a mechanical mixing technique and comprised of 100wt.% Fe2O3 was used. It was demonstrated that hydrogen can be produced from three representative coals - a Russian bituminous, a German lignite and a UK sub-bituminous coal. Depending on the fuel, pure H2 with [CO] ≲50vol.ppm can be obtained from the proposed process. The cyclic stability of the iron oxide carrier was not adversely affected by contaminants found in syngas which are gaseous above 273K. Stable quantities of H2 were produced over five cycles for all three coals investigated. Independent of the fuel, SO2 was not formed during the oxidation with steam, i.e. the produced H2 was not contaminated with SO2. Since oxidation with air removes contaminants and generates useful heat and pure N2 for purging, it should be included in the operating cycle. Overall, it was demonstrated that the proposed process may be an attractive approach to upgrade crude syngas produced by the gasification of low-rank coals to pure H2, representing a substantial increase in calorific value, whilst simultaneous capturing CO2, a greenhouse gas. © 2010 Elsevier B.V.

Studying Aggregate in Lysozyme Solution by Atomic Force Microscope

The aggregates in lysozyme solution with different NaCl concentration were investigated by Atomic Force Microscope (AFM). The AFM images show that there exist lysozyme monomers, n-mers and clusters in lysozyme solution when the conditions are not suitable for crystal growth. In favorable conditions for crystal growth, the lysozyme clusters disappear and almost only monomers exist in solution.

Influence of Coriolis force on bulk flows during horizontal Bridgman growth on a centrifuge: a numerical study

Three-dimensional and time-dependent numerical simulations are performed For melt convection in horizontal Bridgman crystal growth tinder high gravity conditions by means of a centrifuge. The numerical results show that Coriolis Force can cause a stabilizing effect on the fluctuations of the melt flow under a specific relation direction and relation rates of the centrifuge as reported in previous experiments (Ma et al., Materials Processing in High Gravity, Plenum Press, New York, 1994, p. 61). The present simulation provides details of the now features associated with the effect of the Coriolis force. There are also some differences between the present three-dimensional and former two-dimensional numerical solutions particularly in the prediction of the critical conditions and flow patterns.

Surface Stability of Epitaxial Elastic Films by Casimir Force

We investigate the morphological stability of epitaxial thin elastic films on a substrate by the Casimir force between the film surface and a flat plate. Critical undulation wavelengths are derived for two different limit conditions. Consideration of the Casimir force in both limit cases decreases the critical wavelength of the surface perturbation.

Investigation of spatial repeatability using a tire force measuring mat

A portable mat for measuring the dynamic tire forces of commercial vehicles is described. The mat is 56 m long and 13 mm thick and has 141 capacitative strip sensors spaced at 0.4-m intervals. The accuracy of the mat for measuring dynamic tire forces generated by heavy commercial vehicles is assessed using an instrumented vehicle. The spatial repeatability of dynamic wheel loads generated by 14 uninstrumented articulated vehicles is investigated, and it is concluded that approximately half of the vehicles tested are likely to contribute to a repeatable pattern of road loading.

Domains beyond the grain boundary

Thin films of inorganic materials are used in diverse applications, typically in polycrystalline form due to their relatively simple production. We have used enhanced piezoresponse force microscopy to investigate the domain distribution within neighbouring grains in thin polycrystalline films of the ferroelectric-ferroelastic system lead zirconate titanate (PZT). We demonstrate that domains are organized into areas with a correlated alignment of the ferroelastic and ferroelectric domains, spanning multiple grain boundaries. We present five typical arrangements of such structures: azimuthal, radial, gradient, and short- and long- range linear domain organizations. Moreover, we discuss the mechanical and electrical constraints that dictate these structures. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Explosive consolidation of amorphous cobalt-based alloys

This paper addresses the explosive consolidation of amorphous cobalt-based alloys. Using the experimental setup introduced in the present paper, specimens with high compact density, excellent magnetic properties and great wearability have been made. In comparison with permalloy and ferrite, the present specimens exhibit superior magnetic properties. Therefore, the compact is deemed as being a promising material for magnetic recording heads.

An Approximate Method For Calculation Of Fluid Force And Response Of A Circular Cylinder At Lock-In

In this paper, equations calculating lift force of a rigid circular cyclinder at lock-in uniform flow are deduced in detail. Besides, equations calculating the lift force on a long flexible circular cyclinder at lock-in are deduced based on mode analysis of a multi-degree freedom system. The simplified forms of these equations are also given. Furthermore, an approximate method to predict the forces and response of rigid circular cyclinders and long flexible circular cyclinders at lock-in is introduced in the case of low mass-damping ratio. A method to eliminate one deficiency of these equations is introduced. Comparison with experimental results show the effectiveness of this approximate method.

Diversidad territorial y desarrollo endógeno en Argentina

Resumen: El presente artículo se propone demostrar que la integración internacional de la economía argentina, junto con el crecimiento de la competencia entre sus distintas regiones, está generando un cambio profundo dentro del sistema productivo y reorganizando el sistema regional y urbano argentino. Para ello, luego de revisar algunos aspectos generales respecto a la influencia de la globalización como impulsora de transformaciones productivas, el autor se aboca a analizar en profundidad los aspectos positivos y negativos de las transformaciones que está viviendo la Argentina.

The Capillary Force In Micro- And Nano-Indentation With Different Indenter Shapes

The influence of the indenter shapes and various parameters on the magnitude of the capillary force is studied on the basis of models describing the wet adhesion of indenters and substrates joined by liquid bridges. In the former, we consider several shapes, such as conical, spherical and truncated conical one with a spherical end. In the latter, the effects of the contact angle, the radius of the wetting circle, the volume of the liquid bridge, the environmental humidity, the gap between the indenter and the substrate, the conical angle, the radius of the spherical indenter, the opening angle of the spherical end in the truncated conical indenter are included. The meniscus of the bridge is described using a circular approximation, which is reasonable under some conditions. Different dependences of the capillary force on the indenter shapes and the geometric parameters are observed. The results can be applicable to the micro- and nano-indentation experiments. It shows that the measured hardness is underestimated due to the effect of the capillary force. (c) 2008 Elsevier Ltd. All rights reserved.

Concentrated-Mass Cantilever Enhances Multiple Harmonics In Tapping-Mode Atomic Force Microscopy

The natural frequencies of a cantilever probe can be tuned with an attached concentrated mass to coincide with the higher harmonics generated in a tapping-mode atomic force microscopy by the nonlinear tip-sample interaction force. We provide a comprehensive map to guide the choice of the mass and the position of the attached particle in order to significantly enhance the higher harmonic signals containing information on the material properties. The first three eigenmodes can be simultaneously excited with only one carefully positioned particle of specific mass to enhance multiple harmonics. Accessing the interaction force qualitatively based on the high-sensitive harmonic signals combines the real-time material characterization with the imaging capability. (C) 2008 American Institute of Physics.