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  • 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

Electrochemical oxidation of the iodate ion

Mc Ardle, Siobhan January 1994 (has links)
No description available.
2

Striding towards self sustainability using Aluminium from Tanzanian kaolin for combination Tanning system

China, Cecilia, Jayakumar, G. C., Hilonga, A., Kanth, S. V., Njau, K. N. 28 June 2019 (has links)
Content: Sustainability is a key factor which control future leather manufacture. Developing several new technologies is one of the primary agenda for sustainability. However, developing countries are facing several challenges which not only limited to best practice technologies but also finding self sustainability in maximizing the available resources. In the present study, an attempt has been made to explore the potential resource of aluminium from kaolin of Pugu hills, Tanzania for combination tanning. Though, extraction of aluminium from several resources are available, there is limited literature pertaining to Tanzania resources. Moreover, the extracted aluminium is basified and studied for its tanning efficiency. Diffraction and vibrational spectroscopic studies were carried out to assess the confirmation of extracted aluminium. Combination tanning has been carried out with vegetable tannins and dialdehyde starch tanning chemicals, which are from natural resources. Leathers tanned with aluminum and wattle resulted with a shrinkage temperature of 118ºC as compared to Al-Dialdehyde starch leathers showed around 90-100ºC. Physical strength characteristics such as tensile, tear and grain crack strength met the standard norms. Grain surface of leathers are found to be smooth which has been confirmed through microscopic studies. The study provides a new insight on accomplishing self sustainability through available resources and manufacture of eco-friendly system. Take-Away: 1. Tanzania is endowed with massive kaolin rich in aluminium, which is potential for application in leather industry for sustainable development of leather industry 2. The combination tanning system using aluminium from Tanzania kaolin with wattle tannins or Dialdehyde starch imparts leather with both physical and organoleptic properties that meet the stipulated norms 3. This new tanning system provides new insight on ecofriendly tanning system for the sustainability of leather industry.
3

Chemical modification of starch in order to get thermoplastic properties

Hallbert, Emma, Wadman, Elsa January 2023 (has links)
There are numerous advantages of replacing traditional non-biodegradable synthetic plastics with bio-based plastics. Starch is globally available, cheap, renewable, and biodegradable. However, starch has a poor product performance and is relatively difficult to process, as conventional melt processing techniques cannot be used. By introducing thermoplastic properties to starch, the mechanical properties and processability can be enhanced. The aim of the project was to modify starch and give it thermoplastic properties. The implementation of this included various experiments, where aromatic, cyclic and aliphatic side groups were added to the biopolymer. The effect of the different side groups provided valuable insight into how the material properties changed. Subsequently, the thermoplastic properties of the modified starch were analyzed by different analytical methods, including Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC). In conclusion, the TGA showed lower thermal stability in the functionalized starch compared to native starch. Some indications of thermoplastic behavior were observed from the DSC. Trade-off between functionality and thermostability needs to be overlooked when aiming to increase thermoplastic behavior and future work should explore TEMPO oxidation, to obtain better results from the TGA. / Det finns många fördelar med att ersätta traditionella, icke-biologiskt nedbrytbara syntetiska plaster med biobaserade plaster. Stärkelse är globalt tillgängligt, billigt, förnybart och nedbrytbart. I nuläget har stärkelse dock en bristande produktprestanda och är relativt svår att bearbeta eftersom konventionella smält bearbetningstekniker inte kan användas. Genom att ge stärkelse termoplastiska egenskaper kan man förbättra de mekaniska egenskaperna och bearbetbarheten. Syftet med projektet var därför att modifiera stärkelse och introducera termoplastiska egenskaper. Genomförandet av detta innefattade flera olika experiment där aromatiska, cykliska och alifatiska sidogrupper tillsattes till stärkelsen. Effekten av de olika sidogrupperna gav värdefull insikt i hur materialegenskaperna förändrades. Därefter analyserades de termoplastiska egenskaperna hos den modifierade stärkelsen med olika analytiska metoder, inklusive Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) och Differential Scanning Calorimetry (DSC). Slutsatsen var att TGA visade en lägre termisk stabilitet hos den funktionaliserade stärkelsen jämfört med i den naturliga stärkelsen samt att vissa indikationer på termoplastiskt beteende observerades med hjälp av DSC analysen. En avvägning mellan funktionalitet och termisk stabilitet bör tas i beaktande i strävandet efter att öka termoplastiskt beteende. Framtida arbete inom ämnet rekommenderas att utforska TEMPO-oxidation för att uppnå bättre resultat från TGA.

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