Cheap beads offer alternative solar-heating storage

A cheap material that can store heat energy collected from the sun during the day that can be released slowly over night has been developed by researchers in the India. The material based on paraffin wax and stearic acid is described in a forthcoming issue of the International Journal of Renewable Energy Technology and could help keep homes warm in sunny parts of the world that get very cold at night without burning wood or fossil fuels.

Mechanical engineer Meenakshi Reddy of Sri Venkateswara College of Engineering and Technology, in Chittoor, Andra Pradesh, and colleagues explain how certain materials, known as phase change materials (PCM) can store a large amount of heat in the form of latent heat in a small volume. PCMs have a high heat of fusion and melt/freeze at a certain temperature. Heat is absorbed when the material melts and released when it freezes. Heated in the sun, the mixture of paraffin wax (which melts at about 37 Celsius) and stearic acid (a fat commonly used to make soap) becomes entirely liquid. However, as it solidifies it slowly releases the stored heat. The process is akin to the phase changing heating that occurs in hand-warmers that contain a PCM but in this case the material does not need to be boiled in a pan or heated in a microwave oven to absorb latent heat.

The team has now tested spherical capsules just 38 millimetres in diameter containing a blend of paraffin and stearic acid, which can be floated on the top of water in a tank. Stearic acid is a lot cheaper on the Indian market than paraffin and more readily available. The team found that costs could be held down without reducing the overall heating efficiency of the capsules by lowering the proportion of paraffin wax.

Solar energy based thermal energy storage system using phase change materials” in Int. J. Renewable Energy Technology, 2012, 3, 11-23

Improving international wind power law

International regulations and laws laid down in 1982 by the United Nations are failing to address the modern issues surrounding the development of offshore wind farms, according to a legal expert at the Russian Academy of Science in Moscow.

Writing in the International Journal of Public Law and Policy, Ekaterina Anyanova explains how alternative methods of energy production, including wind energy, are increasingly important in the face of climate change and efforts to reduce carbon emissions. However, although basic international regulations are contained within the United Nations Convention on the Law of the Sea (UNCLOS), from 1982, more detailed regulation at the international level is now needed.

Despite the fact that only about 40 Gigawatts of power is currently generated worldwide using wind turbines, this figure is set to rise as demand for so-called renewable energy sources rises and pressure to side-step construction of power stations that utilise fossil fuels or nuclear power increases. Offshore wind power is a relatively young technology and has been the subject of much criticism for its putatively detrimental impact on marine ecosystems as well as affecting the aesthetics of coastlines where such wind farms are visible to users of the shore and coastal waters. Nevertheless, offshore does have advantages over land-based wind power although current costs are 40% higher for offshore.

UNCLOS addresses the legal status of the territorial waters, its bed and subsoil. Territorial waters are adjacent to the land territory and internal waters belt of sea, over which extends the sovereignty of a coastal state, explains Anyanova, the breadth of the area of the territorial waters may not exceed 12 nautical miles, measured from baselines and the territorial waters are under the exclusive sovereignty of the coastal state. Within the territorial waters approval for construction of wind farms is required and the construction and functioning of offshore parks must be aligned with the national authorities. Despite this, UNCLOS also grants right of innocent passage through territorial waters, which could then lead to interference or conflict as shipping passes through waters planted with wind turbines and related wiring and equipment.

Anyanova stresses that it is time to develop a single regulatory regime for the construction and use of offshore wind farms to address the deficiencies in the 1982 international law. The new regulations would have to deal with environmental, territorial and others issues in much more detail than is found in the UNCLOS and to broach the subject of disputes between nations that will inevitably arise as offshore wind power becomes a more attractive energy producer.

Offshore wind energy and the rules of international law” in Int. J. Public Law and Policy, 2011, 1(3), 299-308

One in four students fail to learn on the Internet

More than one in four students gathering information from the internet forget the knowledge gleaned afterwards, according to a pilot study to be published in the International Journal of Education Economics and Development. The study hoped to investigate just how well students retain knowledge gleaned from the internet and revealed that almost 73% of participants had low to moderate knowledge retention.

Zakaria Saleh of Yarmouk University, in Irbid, Jordan, explains how students are increasingly turning to the internet, and specifically the World Wide Web to help them gather information for schoolwork and related tasks. However, there are concerns among educators that there is no indication as to whether or not students understand or think critically about the information they find. The issue of knowledge retention is also yet to be fully addressed by educational researchers, he adds.

The so-called “digital natives”, youngsters who have grown up in a world in which information technology and access to the Internet are almost ubiquitous, are the first generation to have used computers in learning throughout their lives. As such, educational policy has focused on employing these tools increasingly in recent years. “The internet offers students with the possibility to acquire knowledge without time and space constraints,” says Saleh, “Nevertheless, the added value of the internet should be viewed in the learning and knowledge retention, and not just in the instrument used to vehicle new contents and new concepts.”

Saleh has surveyed a limited number of undergraduate and graduate students, 153, to test various hypotheses pertaining to knowledge retention, student attitudes to the internet and how educators approach the use of information technology. The computer skills of most of the participants (131) were generally above population averages and more than half indicated that they have average or better than average internet skills (88 participants). The majority use the internet as an information source for assignments.

The results confirmed earlier studies regarding the ease of use of the internet as an information source. However, Saleh was more concerned with the way in which internet use affects knowledge retention among students. He found that overall use was high, at more than 1 in 10 of participants, but that for almost three-quarters of the students knowledge retention of information obtained via the internet was low to moderate. Graduate students were better at retaining such information than undergraduates, although graduate students tend to be more dedicated to learning and are often selected as being among the brighter students on a course.

The findings should nevertheless, “flag an alert for educators when they rely on the internet for their students’ knowledge acquisition and retention,” Saleh says. He adds that there is now an, urgent needed to conduct further research to measure the effectiveness of using the internet as a source of information in the learning process.

Zakaria I. Saleh (2011). A framework to evaluate the likelihood of knowledge retention when college students obtain information from the internet Int. J. Education Economics and Development, 2 (4), 363-379