Titan: Life on another world?

Student-JosefJCV-1108By Josef Borg

If you were to travel back in time to Earth’s distant past, about three billion years ago, you would find a planet bearing barely any semblance to today’s world. A toxic atmosphere primarily composed of methane swathed our planet as its surface, devoid of liquid water at the time, was incessantly bombarded by small asteroids. While time travel evades our current realm of possibilities, we do have a replica of this past, primordial Earth right in our cosmic backyard!Continue reading

Healing Stone… by infection

Roderick Micallef has a long family history within the construction industry. He coupled this passion with a fascination with science when reading for an undergraduate degree in Biology and Chemistry (University of Malta). To satisfy both loves, he studied the chemical makeup and physical characteristics of Malta’s Globigerina Limestone.

Micallef (supervised by Dr Daniel Vella and Prof. Alfred Vella) evaluated how fire or heat chemically change limestone. Stone heated between 150˚C and 450˚C developed a red colour. Yellow coloured iron (III) minerals such as goethite (FeOOH) had been dehydrated to red coloured hematite (Fe2O3). If the stone was heated above 450˚C it calcified leading to a white colour. This colour change can help a forensic fire investigator quickly figure out the temperature a stone was exposed to in a fire — an essential clue on the fire’s nature.

While conducting this research, Micallef came across an Italian study that had concluded that different strains of heterotrophic bacteria can consolidate concrete and stone. Locally, Dr Gabrielle Zammit had shown that this process was happening on ancient limestone surfaces (Zammit et al., 2011). These bacteria have the potential to act as bio-consolidants and Micallef wanted to study if they could be used to reinforce the natural properties of local limestone and protect against weathering. 

Such a study is crucial in a day and age where the impact of man on our natural environment is becoming central to scientific research. The routine application of conventional chemical consolidants to stone poses an environmental threat through the release of both soluble salt by-products and peeled shallow hard crusts caused by incomplete binding of stone particles. Natural bio-consolidation could prove to be an efficient solution for local application and is especially important since Globigerina Limestone is our only natural resource. 

This research is part of an Master of Science in Cross-Disciplinary Science at the Faculty of Science of the University of Malta, supervised by microbiologist Dr Gabrielle Zammit, and chemists Dr Daniel Vella and Prof. Emmanuel Sinagra. The research project is funded by the Master it! Scholarship scheme, which is part-funded by the EU’s European Social Fund under Operational Programme II — Cohesion Policy 2007–2013.

Scientific beauty of diamonds

Laptops and mobiles are smaller, thinner, and more powerful than ever. The drawback is heat, since computing power comes hand in hand with temperature. Macs have been known to melt down, catch fire and fry eggs — PCs can be even more entertaining. David Grech (supervised by Prof. Emmanuel Sinagra and Dr Ing. Stephen Abela) has now produced diamond–metal matrix composites that can remove waste heat efficiently.

Diamonds are not only beautiful but have some remarkable properties. They are very hard, can withstand extreme conditions, and even transfer heat energy faster than any metals. This ability makes diamonds ideal as heat sinks and spreaders.

The gems are inflexible making them difficult to mould into the complex shapes demanded by the microelectronics industry. By linking diamonds with other materials, new architectures can be constructed. Grech squashed synthetic diamond and silver powders together at the metal’s melting point. The resulting composite material expanded very slowly when heated. The material could dissipate heat effectively, and was cheaper and simpler to produce than current methods — a step closer to use on microchips.

Grech’s current research is focused on obtaining novel types of interfaces between the diamond powders and the metal matrix. The new materials can improve the performance of heat sinks. New production techniques could help make these materials. By depositing a very thin layer of nickel (200 nanometres thick) on diamond powders using a chemical reaction, the gems would form chemical bonds with the layer while the metal matrix would form metallic bonds. The material would transfer heat quickly and expand very slowly on heating. A heat sink made out of this material would give us a cooler microprocessor and powerful electronics that does not spontaneously catch fire — good news for tech lovers.

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This research was performed as part of a Bachelor of Science (Hons) at the Faculty of Science. It is funded by the Malta Council for Science and Technology through the National Research and Innovation Programme (R&I 2010-25 Project DIACOM) and IMA Engineering Services Ltd.