Environmental Assessment of Rammed Earth Construction Systems

Present concerns for sustainable development have led to a revival of traditional building practices using natural or recycled resources. There is a perception that buildings constructed from such materials are environmentally benign. This perception is questionable, as often no evaluation is undertaken to assess the associated environmental impacts. Rammed earth is one such construction technology that has seen renewed interest in recent years. The energy required to manufacture materials (i.e. embodied energy) is a significant component of the life cycle energy associated with buildings. This paper assesses the embodied energy of rammed earth construction relative to brick veneer and cavity brick construction. Rammed earth was found to have significantly less embodied energy than cavity brick construction (to which it is closer in thermal performance), but was approximately equivalent to brick veneer construction. Topics of further research identified include thermal performance and strategies for reducing the embodied energy of cement used for earth stabilisation.

Quasiclassical trajectory calculations of collisional energy transfer in propane systems: multiple direct-encounter hard-sphere model

Quasiclassical trajectory calculations of collisional energy transfer from highly vibrationally excited propane + rare gas systems are reported. This work extends our hard-sphere model (A. Linhananta and K. F. Lim, Phys. Chem. Chem. Phys., 2000, 2, 1385) to examine the variation of the internal energy during collisions with a rare bath gas. This was accomplished by recording the vibrational and rotational energy of propane after each atom–atom encounter during trajectory simulations of propane + rare gas systems. This provides detailed information of the energy flow during a collision. It was found that collisions with small number of encounters transfer energy efficiently, whereas those with many encounters do not. Detailed analyses reveal that the former collisions arise from trajectories with high initial impact parameter, whereas the latter have small initial impact parameter. The reason behind this is the dependence of collision energy transfer (CET) of large polyatomic molecules on their shape. This is connected to the well-known role of rotational energy transfer (RET) as a gateway for CET.

Piercing the decision-making sphere : happiness as the key to real shareholder participation

The purpose of this article is to explain why recent corporate governance reforms and initiatives proclaiming to enhance shareholder participation and elevate shareholder rights, do not go far enough. Indeed, it is suggested that corporate governance polices and reform programs, which have emerged across the world in response to a number of high-profile corporate collapses, act to re-emphasise the limited, 'passive' role which individual shareholders have traditionally experienced in public companies. Although increasing the amount information provided to shareholders about corporate decisions and strategies, and providing shareholders with a greater opportunity to participate in annual general meetings, do go some way in 'empowering' shareholders, it is argued that shareholders essentially remain passive observers, rather than becoming active participants. To become active participants, or corporate governance 'insiders " it is argued that corporate law needs to be directed at piercing the 'decision-making sphere' for individual shareholders in public companies. This involves accommodating an active role for shareholders in the actual decision-making processes of the corporation, rather than simply being informed of decisions that are made and being entitled to veto decisions at the annual general meeting. The second part of the article looks specifically at how the 'oppression' or 'unfair prejudice' remedy, the most commonly used shareholder remedy, is capable - if reformulated so that the pursuit of happiness, rather than vague notions of 'fairness' and 'justice' is the central objective of the remedy - of being used to influence a change of culture within public companies directed at facilitating an active participatory role for shareholders.

'New heaven and new earth': translation and conversion on Aneityum

The idea that 19th-century Europeans and Islanders faced each other across virtually impassable linguistic and cultural boundaries has been a model for Pacific ethnohistory and can, perhaps, be traced in part to the Sapir-Whorf theory of linguistic incommensurability. Based on a case study concerning the translation of the Aneityum [Anejom] bible in Southern Vanuatu in the mid-19th century, the article considers whether the engagement between Islanders and missionaries might be better investigated through the dynamic dialogic model of Bakhtin and Voloshinov: thus speakers and interlocutors on Aneityum actively sought to understand each other through debates and dialogues about the new deity and His place in the spiritual cosmos of the island. The article first discusses the Protestant missionary defence of linguistic parity and commensurability and the formal practices of 19th-century British bible translation; then analyses debates on the new God's efficacy between missionary John Geddie and Nohoat, the foremost sorcerer of the area; and concludes by considering the translation of words particularly important to the Christian faith.

Evaluating rammed earth aalls: a case study

The following research has been undertaken as a response to the recent controversy regarding the suitability of rammed earth wall construction as an effective building envelope. Empirical (in-situ) measurements of temperature and heat flux are taken on the walls of an existing rammed earth building in New South Wales, Australia. An analysis is performed which examines the influence of walls, floor, ceiling and windows on the recorded temperatures within the building. It appears that diffuse sky radiation transmitted by the windows is an important factor in the summer heat load, and that night time cooling coupled with thermal mass has a valuable conditioning effect.

Validated model and study of a rammed earth wall building

A 2100 m² (GFA) two-storey rammed earth building was built on the Thurgoona campus of Charles Sturt University in 1999. The building is novel both in the use of materials and equipment for heating and cooling. The climate at Wodonga can be characterised as hot and dry, so the challenge of providing comfortable working conditions with minimal energy consumption is considerable. This paper describes a thermal model of one of the second-storey offices on the west-end of the building. The simulation software, TRNSYS, has been used to predict office temperatures and comparisons are made between these and measurements made over a typical week in summer. Reasonable agreement has been achieved under most conditions. The model has been used to investigate key building parameters and strategies, including night flushing, to improve the thermal comfort in the office.

The effect of artificial defects on the compressive properties of hollow sphere cellular aluminium (HSCA)

Hollow sphere cellular aluminium (HSCA) samples were fabricated by bonding together two kinds of single aluminium hollow spheres with the same outside diameter of 4 mm but different wall thicknesses of 0.1 mm and 0.3 mm, in which the hollow spheres with the thinner sphere wall thickness were used as artificial defects. Four types of HSCA samples with the same relative density but various distributions of artificial defects were prepared by simple cubic packing. For comparing, HSCA sample without defective hollow spheres inside was also prepared. The effects of the distribution of the artificial defects on the deformation behaviours and mechanical properties were investigated by compressive tests. Results indicated that the nominal stress - nominal strain curve and the deformation behavior of the HSCA samples varied with the distribution of the artificial defects in spite of the same relative density. It is therefore suggested that the deformation behavior and mechanical property of cellular materials were also significantly affected by the distribution of defects. In particular, the plateau stress of the HSCA samples increased with the decrease in number of contact points between the normal hollow spheres and the defective hollow spheres in the loading direction during deformation.

Compressive properties and energy absorption of hollow sphere aluminium

Manufactured cellular aluminums have been developed for a wide range of automotive applications where weight savings, improved safety, crashworthiness and comfort are required. The plateau deformation behavior of cellular aluminums under compressive loading makes this new class of lightweight materials suitable for energy absorption and comes close to ideal impact absorbers. In the present study, aluminum hollow hemispheres were firstly processed by pressing. Hollow sphere aluminum samples with a body-centered cubic (BCC) packing were then fabricated by bonding together single hollow spheres, which were prepared by adhering together hollow hemispheres. Hollow sphere aluminum samples with various kinds of sphere wall thicknesses of 0.1 mm, 0.3 mm and 0.5 mm but the same outside diameter of 4 mm were investigated by compressive tests. The effects of the sphere wall thickness on the mechanical properties and energy absorption characteristics were investigated.

Processing and mechanical properties of hollow sphere aluminum foams

Hollow sphere metallic foams are a new class of cellular material that possesses the attractive advantages of uniform cell size distribution and regular cell shape. These result in more predictable physical and mechanical properties than those of cellular materials with a random cell size distribution and irregular cell shapes. In the present study, single aluminum hollow spheres with three kinds of sphere wall thickness as 0.1 mm, 0.3 mm and 0.5 mm were processed by a new pressing method. Hollow sphere aluminum foam samples were prepared by bonding together single hollow spheres with simple cubic packing (SC) and body-centered cubic packing (BCC). Compressive tests were carried out to evaluate the deformation behaviors and mechanical properties of the hollow sphere aluminum foams. Effects of the sphere wall thickness and packing style on the mechanical properties were investigated.

Study of heat flow through a rammed earth wall building

In 1999, a 2100 m2 (GFA) two-storey rammed earth building was built on the Thurgoona campus of Charles Sturt University. The climate at Thurgoona is considered Mediterranean – hot dry summers and cool winters. The internal and external walls of the building are constructed from 300-mm thick rammed earth (pise) and are load bearing. The thermal performance of the building has been investigated, both experimentally and theoretically over the summer and winter seasons of 2000/1. As part of these investigations heat flux sensors and thermistors were embedded in one of the external walls of a ground floor office, and data from the transducers has been used to determine the heat flow at the internal and external wall surfaces. The simulation software, TRNSYS, has been used to model the thermal performance of the same office. The programme allows the user to calculate the heat flow at the walls, which define any particular thermal zone. A comparison of measured and predicted values of heat flows and air temperatures has been used to validate the model. The model has then been used to simulate the effect of shading and added insulation on the thermal performance of the external walls in both summer and winter and these results are also presented in this paper.