• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 1
  • Tagged with
  • 7
  • 4
  • 4
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The lime industry, a potential business area for Kanthal / Kalkindustrin, en möjlig marknad för Kanthal

Ejenstam, Jesper January 2010 (has links)
<p>The subject of this M.Sc. thesis is to find out whether the lime industry is a possible business area for Kanthal AB. The lime industry is one of the biggest chemical industries in the world and it is very energy demanding. In the process of making quicklime, calcium oxide, a lot of energy is needed as the dissociation of limestone, which consists mainly of calcium carbonate, takes place in the temperature span between 900°C and 1300°C. The total production of quicklime was in 2009 about 280 million tonnes, and the selling price was about $100 per ton. Today, all limekilns are driven by fossil fuels, i.e. oil, coal and gas. The increasing demand on lowering the emissions of carbon dioxide strongly affects the industry, as it is responsible for about 2 % of the total emissions of carbon dioxide. The industry itself claims that the emissions may only be reduced about 10 %, although at very high costs. Kanthal AB produces electric heating solutions that may be suitable for lime production. However, the lime industry is conservative and the use of electricity for lime production is not economically feasible today. Most of the electricity comes from coal power plants and therefore the use of electricity would not be more environmentally friendly in most countries. New limekilns, which are more environmentally friendly, are on the way. These kilns do not necessarily have to use fossil fuels, provides a purer end product and the emission of carbon dioxide is minimized. The size of the production is also much lower, but the end products might be used in more demanding areas, e.g. the pharmaceutical industry, and be sold at a higher price. It is this area Kanthal has to focus on if going to enter the lime industry at this point.</p>
2

The lime industry, a potential business area for Kanthal / Kalkindustrin, en möjlig marknad för Kanthal

Ejenstam, Jesper January 2010 (has links)
The subject of this M.Sc. thesis is to find out whether the lime industry is a possible business area for Kanthal AB. The lime industry is one of the biggest chemical industries in the world and it is very energy demanding. In the process of making quicklime, calcium oxide, a lot of energy is needed as the dissociation of limestone, which consists mainly of calcium carbonate, takes place in the temperature span between 900°C and 1300°C. The total production of quicklime was in 2009 about 280 million tonnes, and the selling price was about $100 per ton. Today, all limekilns are driven by fossil fuels, i.e. oil, coal and gas. The increasing demand on lowering the emissions of carbon dioxide strongly affects the industry, as it is responsible for about 2 % of the total emissions of carbon dioxide. The industry itself claims that the emissions may only be reduced about 10 %, although at very high costs. Kanthal AB produces electric heating solutions that may be suitable for lime production. However, the lime industry is conservative and the use of electricity for lime production is not economically feasible today. Most of the electricity comes from coal power plants and therefore the use of electricity would not be more environmentally friendly in most countries. New limekilns, which are more environmentally friendly, are on the way. These kilns do not necessarily have to use fossil fuels, provides a purer end product and the emission of carbon dioxide is minimized. The size of the production is also much lower, but the end products might be used in more demanding areas, e.g. the pharmaceutical industry, and be sold at a higher price. It is this area Kanthal has to focus on if going to enter the lime industry at this point.
3

The effects of quicklime on the decomposition process in a tropical climate

Ortiz, Meisshialette 24 March 2023 (has links)
Forensic anthropology, forensic taphonomy and forensic entomology are specialties that greatly contribute to judicial investigations and the identification of a decomposing corpse. This research examines the effect of calcium oxide (CaO), known as “quicklime”, on the decomposition process of human remains in a tropical climate. Quicklime has been used since the Early Iron Age, in wars, mass graves and today by criminals, as there is a belief or social myth that it can speed up the process of decomposition of bodies. However, there are no studies on the effect of this chemical on decomposing bodies in a tropical climate. Puerto Rico, in addition to having this climate, has a high crime rate related to drug trafficking. This study uses a series (n=10) of pig (Sus scrofa) burials as a model for human corpses, which were documented through photographs and state of decomposition, as well as climatic conditions, soil pH, odor of decomposition, and the lost mass. The author hypothesizes that the tropical climate contributes to the rapid decomposition of bodies by altering their appearance and morphology; since it is warmer, bacteria multiply more quickly and the entomofauna is more active, in comparison with studies already carried out in temperate climates. In addition, quicklime helps soft tissue decomposition proceed faster and reduces decomposition odor. Among the results, it was observed that there was no acceleration in the decomposition process due to the application of calcium oxide, and this chemical does not have the qualities attributed to it by social myths regarding the complete destruction of human remains, which could be considered an advantage for investigators in cases where there is a buried corpse covered in quicklime. However, it was possible to show that among other effects of quicklime, it subjectively reduces the odor of decomposition, inhibits and/or reduces the activity of the entomofauna, maintains a soil with an alkaline pH and therefore caused the mummification of the body. It can be suggested that the tropical climate helps in an effective decomposition due to the high temperatures, the humidity, and the activity of the entomofauna. Therefore, in both temperate and tropical climates, quicklime does not accelerate the decomposition process, but in a tropical climate it can inhibit the activity of entomofauna and the odor of decomposition. Statistically, results show that the Total Body Score (TBS) did not vary significantly, but the percentage of Mass Loss (ML) had a statistical difference due to the adhesion of the compacted quicklime to the experimental carcasses which increased the overall mass and not because a difference in the actual tissue loss was measured. This is since the decay process almost stopped after 77 days of burial and the mass loss nearly ceased, because with more days of rain and humidity, the more chemical reaction quicklime does (turning it into hydrated lime), causing solidification and mummification in the experimental pig carcasses. The quicklime also maintained an alkaline pH in the pig carcasses compared to the acidic pH of the controls after the decomposition. Therefore, quicklime causes a very sudden dehydration, and, in this sense, it prevents the proliferation of bacteria and, therefore, putrefaction, causing a mummification process. In addition, with the results obtained in this investigation and in other future ones, it will be possible to add scientific, anthropological, and forensic data on the analysis of the effects of quicklime in the stages of decomposition of human remain and in different deposition environments, to establish the time elapsed between death and the moment in which the body has been buried (exposed or not to quicklime) and contribute to criminal cases.
4

Low energy pre-blended mortars: Part 1-Control of the sand drying process using a lime drying technique

Hughes, David C., Illingworth, J.M. 10 November 2015 (has links)
No / Produttion control methods allow factory produced mortars to be supplied to a more consistent formulation than site produced mortars. However, there is scope to enhance their "sustainability" credentials by addressing the methods of drying the wet sand and the use of lower energy hydraulic components. This paper describes the development of a technique in which quicklime is added in controlled quantities to remove free water by both chemical combination and evaporation. The slaked lime so generated is porous and a third mechanism of absorption is suggested which, however, might have adverse effects during storage of the pre-blended mortar. The principal process-control factors are lime addition based upon a ratio of the stoichiometric requirements for complete slaking of the quicklime, free moisture content of the sand, mixing time of the combined sand and quicklime, and storage of the mixed material. (C) 2015 Elsevier Ltd. All rights reserved.
5

Sustainability measures in quicklime and cement clinker production

Eriksson, Matias January 2015 (has links)
This thesis investigates sustainability measures for quicklime and cement clinker production. It is the aim of this thesis to contribute to the effort of creating a more sustainable modus of industrial production. The methods used comprises process simulations through multicomponent chemical equilibrium calculations, fuel characterization and raw materials characterization through dynamic rate thermogravimetry. The investigated measures relate to alternative fuels, co-combustion, oxygen enrichment, oxyfuel combustion, mineral carbonation and optimizing raw material mixes based on thermal decomposition characteristics. The predictive multicomponent chemical equilibrium simulation tool developed has been used to investigate new process designs and combustion concepts. The results show that fuel selection and oxygen enrichment influence energy efficiency, and that oxyfuel combustion and mineral carbonation could allow for considerable emission reductions at low energy penalty, as compared to conventional post-combustion carbon dioxide capture technologies. Dynamic rate thermogravimetry, applied to kiln feed limestone, allows for improved feed analysis with a deeper understanding of how mixing of different feed materials will affect the production processes. The predictive simulation tool has proven to be of practical value when planning and executing production and full scale campaigns, reducing costs related to trial and error. The main conclusion of this work is that several measures are available to increase the sustainability of the industry.
6

The effects of lime on the decomposition of buried human remains : a field and laboratory based study for forensic and archaeological application

Schotsmans, Eline Marie Joseph January 2013 (has links)
The inclusion of lime in burials is observed in historical and archaeological records, in contemporary mass graves and forensic cases. Clearly there are controversies within the literature and there is a general misconception of the effects of lime on decomposition. Recent casework in Belgium and the UK involving the search for human remains buried with lime, have demonstrated the need for a more detailed understanding of the effect of different types of lime on cadaver decomposition and its micro-environment. Field and laboratory experiments using pigs as human body analogues were undertaken to obtain a better understanding of the taphonomic processes that govern lime burials. The changes observed in the experiments were related back to archaeological parallels in which white residues have been found. The combined results of these studies demonstrate that despite conflicting evidence in the literature, hydrated lime and quicklime both delay the initial stages of the decay process but do not arrest it completely. The end result is ultimately the same: skeletonisation. Furthermore this study stresses the importance of the specific microenvironment in taphonomic research and highlights the need for chemical analysis of white residues when encountered in a burial. Not all white powder is lime. White residue could be identified as calcium carbonate, building material, body decomposition products, minerals or degraded lead. This study has implications for the investigation of clandestine burials and for a better understanding of archaeological plaster burials. Knowledge of the effects of lime on decomposition processes also have bearing on practices involving the disposal of animal carcasses and potentially the management of mass graves and mass disasters by humanitarian organisation and DVI teams.
7

The effects of lime on the decomposition of buried human remains. A field and laboratory based study for forensic and archaeological application.

Schotsmans, Eline M.J. January 2013 (has links)
The inclusion of lime in burials is observed in historical and archaeological records, in contemporary mass graves and forensic cases. Clearly there are controversies within the literature and there is a general misconception of the effects of lime on decomposition. Recent casework in Belgium and the UK involving the search for human remains buried with lime, have demonstrated the need for a more detailed understanding of the effect of different types of lime on cadaver decomposition and its micro-environment. Field and laboratory experiments using pigs as human body analogues were undertaken to obtain a better understanding of the taphonomic processes that govern lime burials. The changes observed in the experiments were related back to archaeological parallels in which white residues have been found. The combined results of these studies demonstrate that despite conflicting evidence in the literature, hydrated lime and quicklime both delay the initial stages of the decay process but do not arrest it completely. The end result is ultimately the same: skeletonisation. Furthermore this study stresses the importance of the specific microenvironment in taphonomic research and highlights the need for chemical analysis of white residues when encountered in a burial. Not all white powder is lime. White residue could be identified as calcium carbonate, building material, body decomposition products, minerals or degraded lead. This study has implications for the investigation of clandestine burials and for a better understanding of archaeological plaster burials. Knowledge of the effects of lime on decomposition processes also have bearing on practices involving the disposal of animal carcasses and potentially the management of mass graves and mass disasters by humanitarian organisation and DVI teams. / Arts and Humanities Research Council (AHRC) and the University of Bradford

Page generated in 0.0245 seconds