32,279 research outputs found
Effect of heating rate on gas emissions and properties of ïŹred clay bricks and ïŹred clay bricks incorporated with cigarette butts
In general, the ïŹring process of clay bricks generates a range of gas emissions into the atmosphere. At high
concentrations, these volatile emissions can be a serious source of environmental pollutions. The main purpose
of this study was to evaluate the effect of different heating rates on gas emissions and properties during the ïŹring of clay bricks and clay bricks incorporated with cigarette butts (CBs). In this investigation, four different heating rates were used: 0.7 °C minâ1â1, 2 °C minâ1, 5 °C minâ1 and 10 °C min. The samples were ïŹred in solid form from room temperature to 1050 °C. During the ïŹring cycles, carbon monoxide, carbon dioxide, nitrogen oxides,hydrogen cyanide and chlorine emissions were measured at different heating rates. All bricks were also tested for their physical and mechanical properties including dry density, compressive strength, tensile strength, water absorption and initial rate of absorption. Results show that gas emissions were reduced signiïŹcantly
with higher heating rates (10 °C min) followed by 5 °C minâ1â1
and 2 °C min for both types of brick samples.
Higher heating rates also decrease the compressive strength and tensile strength value but demonstrate an
insigniïŹcant effect on the water absorption properties respectively. In conclusion, a higher heating rate is preferable in terms of decreasing gas emissions and it is also able to produce adequate physical and mechanical properties especially for the CB brick
Challenges in the Analysis of Historic Concrete:Understanding the Limitations of Techniques, the Variability of the Material and the Importance of Representative Samples
Biodegradability standards for carrier bags and plastic films in aquatic environments: a critical review
Plastic litter is encountered in aquatic ecosystems across the globe, including polar environments and the deep sea. To mitigate the adverse societal and ecological impacts of this waste, there has been debate on whether âbiodegradableâ materials should be granted exemptions from plastic bag bans and levies. However, great care must be exercised when attempting to define this term, due to the broad and complex range of physical and chemical conditions encountered within natural ecosystems. Here, we review existing international industry standards and regional test methods for evaluating the biodegradability of plastics within aquatic environments (wastewater, unmanaged freshwater and marine habitats). We argue that current standards and test methods are insufficient in their ability to realistically predict the biodegradability of carrier bags in these environments, due to several shortcomings in experimental procedures and a paucity of information in the scientific literature. Moreover, existing biodegradability standards and test methods for aquatic environments do not involve toxicity testing or account for the potentially adverse ecological impacts of carrier bags, plastic additives, polymer degradation products or small (microscopic) plastic particles that can arise via fragmentation. Successfully addressing these knowledge gaps is a key requirement for developing new biodegradability
standard(s) for lightweight carrier bags
Productivity in the Forest Products Sector: A Review of the Literature
The present literature review is an attempt to gather and summarize the extent of our knowledge of the productivity trends and levels in the forest products sector. We consider single factor as well as total factor productivity definitions. The studies ?from around the world but mainly focusing on the Canadian and American forest product industries ?have been regrouped in sections: (1) general, (2) logging, (3) saw milling, lumber and wood products, and (4) pulp and paper studies.The report also synthesizes the findings of the studies along two lines: (1) the overall productivity growth trends in Canada and other countries and a comparison between forest products sectors in Canada and the United States; and (2) the determinants of productivity growth.Forestry, Forest Products, Logging, Wood Products, Primary Manufacturing, Primary Industries, Pulp and Paper, Paper Products, Forestry Industry, Canada, United States, Productivity, Productivity Growth
A laboratory study on cold-mix, cold-lay emulsion mixtures
This paper describes laboratory experiments and presents
results for the performances of cold-mix, cold-lay
emulsion mixtures. The main objective of the experiments
was to evaluate and improve the properties of the cold
mixtures. The mixture properties evaluated were:
volumetric properties, indirect tensile stiffness modulus
(ITSM), repeated load axial creep and fatigue. These
properties were compared with conventional hot asphalt
mixtures not containing any waste/recycled materials. To
optimise the performances of the mixtures, a target of
ITSM value of 2000 MPa was selected. At full curing
conditions, the stiffness of the cold mixes was found to be
very similar to that of hot mixtures of the same
penetration grade base bitumen (100 pen). Test results
also show that the addition of 1â2% cement significantly
improved the mechanical performance of the mixes and
significantly accelerated their strength gain. The fatigue
behaviour of the cold mixes that incorporated cement was
comparable with that of the hot mixtures
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Modelling and optimisation of design of non-conventional instrument transformers
In this paper, we have proposed, modelled and optimised several designs of non-conventional instrument transformer (NCIT) for high voltage overhead transmission lines (400kV). We have discussed several parameters and investigated how they influence the sensitivity of our NCIT, consisting of magnetic shape memory (MSM) element, magnetic circuit and an LVDT (linear variable differential transformer). One of the most used conductors in these lines, 528-Al1/69-ST1A ACSR conductor (old code MOOSE), was modelled together with the MSM element and the magnetic circuit in ANSYS APDL. Based on the obtained results we have given suggestions on how NCIT could be designed taking into account a choice of the most appropriate material for this application. The way how the model was developed was presented as well as calculations of errors in the model in ANSYS APDL for electromagnetic problems
Increasing convergence between the recognition of an intangible asset for financial accounting purposes and strategic management accounting and project management techniques
New management techniques such as 'just-in-time', 'lean manufacturing' and 'Six Sigma' allow management accountants to shift their focus from the management and control of production processes to the management of strategic issues. This paradigm shift resulted from shorter product life cycles, due to technological advances and a more competitive business environment. Recent revisions to the International Accounting Standards which are particularly supportive of life cycle costing and project management are likely to increase the focus on strategic management accounting further. This article describes developments in management accounting and the recent convergence of financial reporting in terms of International Accounting Standards with strategic management accounting and project management techniques. Strategic management accounting (particularly life cycle costing) involves applying project management techniques and using the calculus of investment to manage the project as a whole. This contrasts with managing only costs and revenues during the manufacturing phase of a project. The article demonstrates that project management techniques and the calculus of investment provide the information needed to account for the value of a project in terms of IAS 38: Intangible Assets. This will ultimately give rise to both improved decision-making and more relevant financial reporting
Thermal, mechanical and microstructural analysis of concrete containing microencapsulated phase change materials
This paper studies the thermal, mechanical and microstructural aspects of concrete containing different amounts of microencapsulated phase change materials (PCMs). In addition, numerical simulation is carried out to study the potential application of PCM-modified concrete for reduction in summer surface temperature. It is shown that increasing PCM content in concrete led to lower thermal conductivity and an increase in the heat storage ability of concrete. However, the compressive and flexural strength of concrete significantly decreased. Microstructural analysis showed that PCMs appear to remain intact during mixing; however, PCM particles appear to fail by bursting under loading, creating hemispherical voids and crack initiation points as well as possible entrapped air behaviour. The result of numerical simulation revealed that reduction in summer concrete pavement surface temperature by several degrees was possible, with implications for reduction in concrete thermal stresses, shrinkage and urban heat island effect
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