238,004 research outputs found
Regeneration Of Thermally Recycled Glass Fibre For Cost-Effective Composite Recycling : Overview of the ReCoVeR projects
No full textGlobal production of composite materials in 2015 will significantly exceed 10 million tons. Glass fibre reinforced composites account for more than 90% of all the fibre-reinforced composites currently produced. Development of economically viable processes for recycling end-of-life glass fibre composites would have major economic and environmental impacts. This presentation introduces the ReCoVeR projects on enabling cost-effective performance regeneration of glass-fibres from thermal recycling of end-of-life automotive and wind energy composites. ReCoVeR technology targets treating glass fibre thermally reclaimed from GRP waste in order to regenerate a performance level which is equivalent to new fibres. Composite materials reinforced with ReCoVeR glass fibres can currently attain over 80% of the reinforcement performance of composites produced with pristine glass fibres
The investigation and characterisation of colourless glass from forensic and archaeological contexts using multiple interdisiplinary analytical techniques
No full textThe techniques used to analyse glass in forensics and archaeology differ:
forensic analysis relies almost completely on Refractive Index, whereas archaeology
uses compositional analyses. This thesis focuses on examining, explaining and
challenging those differences through the analysis of colourless glass from forensic
and archaeological contexts.
Two major studies are undertaken, one focussing on stained and painted glass
from Christ Church Cathedral, Oxford, and one based on modern automotive glass.
The analytical techniques common to each discipline are applied to the samples of
glass used in the research. The studies each focus on individual research questions;
the Christ Church study investigates the 17th century Van Linge window scheme, the
compositions of fragments of glass from throughout the cathedral’s history are
investigated, and shown to separate into distinct compositional groups. The study also
successfully recreates the Van Linge window scheme; and the historical and
compositional analyses allowed the study of one of the in-situ painted windows in the
cathedral. The automotive glass study investigates the complex relationship between
glass manufacturers and vehicle manufacturers. The research revealed that certain
makes of vehicle were beginning to group and glass from specific areas of the world
was also grouping together. This study highlights the potential use for glass as a tool
for intelligence gathering rather than just as evidence.
The application of the different analytical techniques to each study is
discussed along with the merits of using each of the techniques. The potential of using
forensic techniques in archaeology and archaeological techniques in forensics is
evaluated. Specifically, LA-ICP-MS, which is rarely used in forensics, could be an
innovative and potentially important tool for the forensic evaluation of cars and other
glass evidence. A discussion of the research and databases needed to make the most of
the techniques is assessed
Upconversion luminescence and thermal effects in terbium-ytterbium codoped fluorogermanate glass-ceramic
No full textCooperative energy transfer upconversion luminescence is investigated in Tb(3+)/Yb(3+)-codoped PbGeO(3)-PbF(2)-CdF(2) glass-ceramic and its precursor glass under resonant and off resonance infrared excitation. Bright UV-visible emission signals around 384, 415, 438 nm, and 473-490, 545, 587, and 623 nm are identified as due to the (5)D(3)((5)G(6))->(7)F(1) (J=6,5,4) and (5)D(4)->(7)F(1) (J=6,5,4,3) transitions, respectively, and readily observed. The results indicate that cooperative energy transfer between ytterbium and terbium. ions followed by excited state absorption are the dominant upconversion excitation mechanisms involved. Comparison of the upconversion process in a glass-ceramic sample and its glassy precursor revealed that the former present much higher upconversion efficiency. The dependence of the upconversion emission upon pump power, temperature, and doping content is also examined
Upconversion luminescence and thermal effects in terbium-ytterbium codoped fluorogermanate glass-ceramic
No full textCooperative energy transfer upconversion luminescence is investigated in Tb(3+)/Yb(3+)-codoped PbGeO(3)-PbF(2)-CdF(2) glass-ceramic and its precursor glass under resonant and off resonance infrared excitation. Bright UV-visible emission signals around 384, 415, 438 nm, and 473-490, 545, 587, and 623 nm are identified as due to the (5)D(3)((5)G(6))->(7)F(1) (J=6,5,4) and (5)D(4)->(7)F(1) (J=6,5,4,3) transitions, respectively, and readily observed. The results indicate that cooperative energy transfer between ytterbium and terbium. ions followed by excited state absorption are the dominant upconversion excitation mechanisms involved. Comparison of the upconversion process in a glass-ceramic sample and its glassy precursor revealed that the former present much higher upconversion efficiency. The dependence of the upconversion emission upon pump power, temperature, and doping content is also examined
Recycled Glass Mixtures as Cast Glass Components for Structural Applications, Towards Sustainability
No full textThe problem of sustainability represents one of the most important issues that the world has to face nowadays, not only in terms of energy consumption and of the consequent CO2 emissions, but also in terms of material waste streams that end in landfill. 38 million tons of glass waste are produced every year in the European Union and new targets have been set for 2020 towards a more sustainable management of such wastes. Nowadays, only the container glass industry has reached a considerable recycling rate, while for all the other sectors we are still witnessing downgrading processes. Looking at the world of construction, glass has been more and more employed as a structural material thanks to its high transparency and compression strength. Although the use of glass can be attractive under multiple aspects and its production is continuously increasing, once employed as a construction element, it is rarely reused or recycled due to the high-quality requirement demanded to the industry of production. Nevertheless, besides its main applications as a 2-dimensional element, the new technology of cast glass has been recognised as a potential mean of glass recycling. Here, glass is designed and used under the form of repetitive 3-dimensional units assembled in a whole geometrical shape. In fact, thanks to its higher load-bearing capacity under monolithic shapes, this glass can admit less restrictions and potentially incorporate different types of waste. For this reason, the aim of this experimental work is to find a possible combination between glass families, specifically soda-lime, borosilicate and lead-crystal glass, to be recycled as cast glass components. Each type of glass was powdered or grinded under the form of cullet and different mixtures were prepared to be melted at temperatures of 970°C, 1120°C and 1200°C through the kiln-cast tecnique. Finally, an experimental splitting test was performed to define a force trend and a fracture behaviour for each sample. Some preliminary results have been achieved drawing the guidelines for a further investigation. Soda-lime-silica glass and lead-crystal glass mixture revealed to be the most compliant glass recipe with the required physical and mechanical properties, when reheated at 1120°C. The decrease in the melting temperature of the compound and the higher transparency given by the addition of lead glass revealed the potential benefit, in terms of sustainability, for future projects
5D data storage by ultrafast laser nanostructuring in glass
No full textThe high-density five dimensional data storage with ultrafast laser writing is demonstrated. The text file is recorded by polarization controlled self-assembled form birefringence and retrieved in glass opening the era of unlimited lifetime data storag
Upconversion luminescence and thermal effects in terbium-ytterbium codoped fluorogermanate glass-ceramic
No full textCooperative energy transfer upconversion luminescence is investigated in Tb(3+)/Yb(3+)-codoped PbGeO(3)-PbF(2)-CdF(2) glass-ceramic and its precursor glass under resonant and off resonance infrared excitation. Bright UV-visible emission signals around 384, 415, 438 nm, and 473-490, 545, 587, and 623 nm are identified as due to the (5)D(3)((5)G(6))->(7)F(1) (J=6,5,4) and (5)D(4)->(7)F(1) (J=6,5,4,3) transitions, respectively, and readily observed. The results indicate that cooperative energy transfer between ytterbium and terbium. ions followed by excited state absorption are the dominant upconversion excitation mechanisms involved. Comparison of the upconversion process in a glass-ceramic sample and its glassy precursor revealed that the former present much higher upconversion efficiency. The dependence of the upconversion emission upon pump power, temperature, and doping content is also examined.UNESP, Inst Quim, BR-14800900 Araraquara, SP, BrazilUniversidade Federal Rural de Pernambuco (UFRPE), Dept Fis, BR-52171900 Recife, PE, BrazilUNESP, Inst Quim, BR-14800900 Araraquara, SP, Brazi
Challenging glass
No full textEditorialGreen Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Structural Design & MechanicsApplied Mechanic
Glass engineering!
No full textEditorialGreen Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Structural Design & Mechanic
Surface plasmon resonance assisted rapid laser joining of glass
No full textRapid and strong joining of clear glass to glass containing randomly distributed embedded spherical silver nanoparticles upon nanosecond pulsed laser irradiation (40 ns and repetition rate of 100 kHz) at 532 nm is demonstrated. The embedded silver nanoparticles were 30–40 nm in diameter, contained in a thin surface layer of -10 µm. A joint strength of 12.5 MPa was achieved for a laser fluence of only 0.13 J/cm2 and scanning speed of 10 mm/s. The bonding mechanism is discussed in terms of absorption of the laser energy by nanoparticles and the transfer of the accumulated localised heat to the surrounding glass leading to the local melting and formation of a strong bond. The presented technique is scalable and overcomes a number of serious challenges for a widespread adoption of laser-assisted rapid joining of glass substrates, enabling applications in the manufacture of microelectronic devices, sensors, micro-fluidic, and medical devices.</p
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