In this edition of Inderscience Research Picks, David Bradley reports on a way to reduce landfill or improve bioethanol productiong, involving domestic drying of food waste, an indoor pedestrian tracking system for safety and security and even social networking applications, a way to deal with the problem of tardy patients in hospital outpatient clinics, and finally how to reclaim valuable cobalt from spent lithium-ion batteries.
Dry food waste
Could a domestic device that desiccates food waste reduce the burden on landfill where local authorities do not have the facilities to compost or otherwise process such material for use as biomass or fertiliser? Researchers in Greece suggest that the mass of domestic food waste could be reduced by almost 80% by drying and volume reduced to less than two-thirds. Such an approach to waste pre-treatment would reduce refuse collection fuel bills as well as landfill volume requirements. The same pre-treatment might also facilitate the production of bioethanol from food waste where such a facility existed locally because drying does not destroy the requisite carbohydrate content. Moreover, desiccated waste could be stored for future use in this regard.
Sotiropoulos, A., Bava, N., Valta, K., Vakalis, S., Panaretou, V., Novacovic, J. and Malamis, D. (2016) ‘Household food waste dehydration technique as a pretreatment method for food waste minimisation’, Int. J. Environment and Waste Management, Vol. 17, Nos. 3/4, pp.273–286.
Where are they now?
A multisensor system for tracking pedestrians in the indoor environment has been developed by researchers in Spain and the USA. The system hooks into smart phones without relying on global navigation satellite systems, GPS, which do not function indoors. The system detects and counts steps on floors and stairs using the standard movement sensor in the phone, which are commonly used by individuals for fitness tracking and other applications. The system can recognises changes of direction and floor and so might be used in safety and security control of pedestrian flow in large shopping malls, office buildings, hospitals or other workplaces. Tracking people in such places could be useful for bringing people together in a timely manner or even keeping them apart as well as helping to ensure safety and security of a building perhaps during busy times or in the event of an emergency. Tests with Android phones were more than 90% accurate, the team reports.
Marron, J.J., Labrador,M.A.,Menendez-Valle, A., Fernandez-Lanvin, D. and Gonzalez-Rodriguez, M. (2016) ‘Multi sensor system for pedestrian tracking and activity recognition in indoor environments’, Int. J. Ad Hoc and Ubiquitous Computing, Vol. 23, Nos. 1/2, pp.3–23.
The trouble with patients
Patients are rarely patient, especially when the call of “The doctor will see you now” is a long time coming. However, research from a team at a large hospital in China suggests that it’s rarely the doctor’s fault even if they spend longer than the allotted time with their outpatient, the real problem lies with patients who are late for their appointment. The study found that extended consultation time can cause delays but the time that all patients will have to wait is minimised the more of them that arrive punctually. The team has developed a new model appointment system that would reduce the impact of tardy patients on others waiting for their appointment. Their model leads to a reduction of just over a third in patient waiting times overall.
Luo, L., Zhou, Y., Han, B.T., Shi, Y., Song, Q., He, X. and Guo, Z. (2016) ‘A simulation model for outpatient appointment scheduling with patient unpunctuality’, Int. J. Simulation and Process Modelling, Vol. 11, Nos. 3/4, pp.281–291.
Reclaiming metals from old batteries
Cobalt is an important metal in the cathode of lithium-ion batteries. Retrieving the valuable metal from spent batteries could be a useful part of reclamation and recycling of waste electrical goods and gadgets. Researchers in Bangladesh have investigated different acid leaching methods for the selective extraction of this metal from batteries. With just 1.5 molar hydrochloric acid (which is weaker than standard “bench” acid used in university teaching laboratories, they saw 93% dissolution by mass of cobalt. It took just one hour at 90 degrees Celsius to extract the metal to that degree as measured by atomic absorption spectrophotometry (AAS). X-ray diffraction (XRD) was used to look at the chemical structure of the battery cathode before and after leaching in order to inform future work aimed at optimising and improving the process for recycling.
Khan, M.Z.H., Alam, M.I., Khatun, M.S., Hasan, M.R., Al-Mamun, M.R., Islam, M.F., Khan, M., Aktar, S., Akther, S. and Fatema, K. (2016) ‘Co recovery from spent Li-ion battery by acid leaching – a comparative study’, Int. J. Environment and Waste Management, Vol. 17, Nos. 3/4, pp.203–215.