Optimization of polymer/ruthenium complex optical oxygen sensor

This thesis is focused on developing an optical oxygen sensor, to detect oxygen content in sealed packages. The oxygen sensor material was developed using tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) dichloride, a well known oxygen sensitive dye. The [Ru(Ph2Phen)3](Cl) 2 dye was incorporated into a polyacrylate polymer in the first step. A plasticizer (dioctylphthalate) was then added to the polymer/ruthenium mixture to improve the oxygen permeability of the sensor material. Optimum composition films were identified by the analysis of fluorescence lifetime decay curves using the OxySense 101 Analyzer. After optimizing each component in the order of polymer, ruthenium and plasticizer, the solution mixture was cured for a minimum of 24 hrs. at 60°C to produce the final cured polymer/ruthenium/plasticizer material. The optimized sensor material was reconstituted and cast onto suitable substrates before testing. The final optimized, cured sensor material contained 0.005 g Ru per 1 g polymer and 1 g dioctylphthalate per 1 g of polymer

Prevention of sports injuries in Sri Lanka: What do we know about injuries in our athletes?

In terms of safeguarding the health and well-being of athletes in Sri Lanka, a primary focus has always been toward the treatment of injuries after they have occurred and promoting rehabilitation back into sport. There has been little attention towards the primary prevention of injuries in Sri Lankan sports. As a developing sporting nation, the benefits of injury prevention are immense: from a public health and financial perspective, through to individual benefits for athletes’ physical, psychological and social health. Understanding the reasons behind the lack of motive towards sports injury prevention in the country, and challenges in developing and implementing injury prevention measures in the field is useful so that these reasons can be addressed and overcome. Based on recent experience in conducting injury prevention research among Sri Lankan junior cricketers, this article discusses injury prevention principles in sport and provides directions for future sport injury prevention research in Sri Lanka

Determinants of Union Participation of Public Sector Organizations in Sri Lanka

This study explores the relationship between various predictors of union participation namely;union loyalty, union instrumentality, them and us attitude and workplace collectivism onemployees’ willingness to participate in union activities of public sector organizations in SriLanka. A structured questionnaire was distributed among randomly selected sample of 254unionized employees in seven large scale highly unionized public sector organizations. Thestatistical results of the study revealed that member attitudes namely; union loyalty and unioninstrumentality were positively associated with union participation. However, union loyalty wasthe significant and most powerful predictor of union participation.Key Words: Union Participation, Union Loyalty, Union Instrumentality, Them and Us attitude,Workplace Collectivis

Continuous combined microwave and hot air treatment of apples for fruit fly (Bactrocera tryoni and B. jarvisi) disinfestation

Apples at 24 ± 2 °C were heated in a pilot scale hot air assisted (40 °C) continuous pentagonal microwave system, to evaluate the effectiveness of this treatment on insect mortality (variety Mutsu) and fruit quality (variety Granny Smith). An average temperature of 53.4 ± 1.3 °C at core, bottom and flesh of the apple was recorded at the end of the treatment. One hundred percent mortality of the most tolerant stage of Queensland fruit fly (Bactrocera tryoni, Froggatt) and Jarvis's fruit fly (Bactrocera jarvisi, Tryon), were observed when the Mortality value (M52, equivalent time of isothermal treatment at 52 °C) at the slowest heating point applicable for each experiment was ≥ 50 min and ≥ 37 min, respectively. Results showed that microwave heat treatment is effective for insect disinfestation without any adverse impact on total soluble solids, flesh or peel firmness of the treated apples. The treated apples recorded a significantly higher pH and lower ion leakage than the untreated apples after 3 or 4 weeks. Therefore, the microwave heat treatment has the potential to be developed as an alternative chemical free quarantine treatment against economically significant insect pests. Industrial relevance Hot air assisted microwave heating of fruits and vegetables, is more cost effective compared to vapour heat treatment and ionising radiation for disinfestation of insects. Microwave treatment is environmentally friendly compared to fumigation and chemical treatments. Hot air assisted microwave disinfestation can be performed at farms or centralised pack houses since the capital cost would be comparatively lower than vapour heat or ionising radiation treatments

Subsumption architecture for enabling strategic coordination of robot swarms in a gaming scenario

The field of swarm robotics breaks away from traditional research by maximizing the performance of a group - swarm - of limited robots instead of optimizing the intelligence of a single robot. Similar to current-generation strategy video games, the player controls groups of units - squads - instead of the individual participants. These individuals are rather unintelligent robots, capable of little more than navigating and using their weapons. However, clever control of the squads of autonomous robots by the game players can make for intense, strategic matches. The gaming framework presented in this article provides players with strategic coordination of robot squads. The developed swarm intelligence techniques break up complex squad commands into several commands for each robot using robot formations and path finding while avoiding obstacles. These algorithms are validated through a 'Capture the Flag' gaming scenario where a complex squad command is split up into several robot commands in a matter of milliseconds

Geographic Coincidence of Increased Malaria Transmission Hazard and Vulnerability Occurring at the Periphery of two Tanzanian Villages.

The goal of malaria elimination necessitates an improved understanding of any fine-scale geographic variations in transmission risk so that complementary vector control tools can be integrated into current vector control programmes as supplementary measures that are spatially targeted to maximize impact upon residual transmission. This study examines the distribution of host-seeking malaria vectors at households within two villages in rural Tanzania. Host-seeking mosquitoes were sampled from 72 randomly selected households in two villages on a monthly basis throughout 2008 using CDC light-traps placed beside occupied nets. Spatial autocorrelation in the dataset was examined using the Moran's I statistic and the location of any clusters was identified using the Getis-Ord Gi* statistic. Statistical associations between the household characteristics and clusters of mosquitoes were assessed using a generalized linear model for each species. For both Anopheles gambiae sensu lato and Anopheles funestus, the density of host-seeking females was spatially autocorrelated, or clustered. For both species, houses with low densities were clustered in the semi-urban village centre while houses with high densities were clustered in the periphery of the villages. Clusters of houses with low or high densities of An. gambiae s.l. were influenced by the number of residents in nearby houses. The occurrence of high-density clusters of An. gambiae s.l. was associated with lower elevations while An. funestus was also associated with higher elevations. Distance from the village centre was also positively correlated with the number of household occupants and having houses constructed with open eaves. The results of the current study highlight that complementary vector control tools could be most effectively targeted to the periphery of villages where the households potentially have a higher hazard (mosquito densities) and vulnerability (open eaves and larger households) to malaria infection

Boomerang: Rebounding the consequences of reputation feedback on crowdsourcing platforms

Paid crowdsourcing platforms suffer from low-quality workand unfair rejections, but paradoxically, most workers and requesters have high reputation scores. These inflated scores, which make high-quality work and workers difficult to find,stem from social pressure to avoid giving negative feedback. We introduce Boomerang, a reputation system for crowdsourcing that elicits more accurate feedback by rebounding the consequences of feedback directly back onto the person who gave it. With Boomerang, requesters find that their highly rated workers gain earliest access to their future tasks, and workers find tasks from their highly-rated requesters at the top of their task feed. Field experiments verify that Boomerang causes both workers and requesters to provide feedback that is more closely aligned with their private opinions. Inspired by a game-theoretic notion of incentive-compatibility, Boomerang opens opportunities for interaction design to incentivize honest reporting over strategic dishonesty

Crowd guilds: Worker-led reputation and feedback on crowdsourcing platforms

Crowd workers are distributed and decentralized. While decentralization is designed to utilize independent judgment to promote high-quality results, it paradoxically undercuts behaviors and institutions that are critical to high-quality work. Reputation is one central example: crowdsourcing systems depend on reputation scores from decentralized workers and requesters, but these scores are notoriously inflated and uninformative. In this paper, we draw inspiration from historical worker guilds (e.g., in the silk trade) to design and implement crowd guilds: centralized groups of crowd workers who collectively certify each other’s quality through double-blind peer assessment. A two-week field experiment compared crowd guilds to a traditional decentralized crowd work model. Crowd guilds produced reputation signals more strongly correlated with ground-truth worker quality than signals available on current crowd working platforms, and more accurate than in the traditional model

Prototype tasks: Improving crowdsourcing results through rapid, iterative task design

Low-quality results have been a long-standing problem on microtask crowdsourcing platforms, driving away requesters and justifying low wages for workers. To date, workers have been blamed for low-quality results: they are said to make as little effort as possible, do not pay attention to detail, and lack expertise. In this paper, we hypothesize that requesters may also be responsible for low-quality work: they launch unclear task designs that confuse even earnest workers, under-specify edge cases, and neglect to include examples. We introduce prototype tasks, a crowdsourcing strategy requiring all new task designs to launch a small number of sample tasks. Workers attempt these tasks and leave feedback, enabling the requester to iterate on the design before publishing it. We report a field experiment in which tasks that underwent prototype task iteration produced higher-quality work results than the original task designs. With this research, we suggest that a simple and rapid iteration cycle can improve crowd work, and we provide empirical evidence that requester “quality” directly impacts result quality