QRA's role in eliminating denger fever in Singapore

The Temperature Cyle proposed by QRA to Stress Screen the Polyethelyne Containers through numerous rounds of Heat and Cold Stressing to induce failure in the container. 

   Last year, QRA was approached by a huge MNC whose Social Enterprise arm was tasked to find ways and means to eradicate the dengue fever menace caused by Aedes mosquitoes in Singapore. Now Singapore is a tropical country, and our climate is very humid. We can record, easily 100 - 120 days of rain per year, so there are instances of water ponding and places where these mosquitoes can breed. 

Aedes is one such specie of mosquito and dengue fever can be deadly. Every year, scores of people, will get infected, and some may die from this disease which is characterised by intermittent high fever, chills, some rashes on the body and the person infected must be hospitalised immediately. 

The chamber providing the Temperature Cycling Test - ETSP Temperature Cycle Chamber (S.Korea) 

The MNC's social enterprise arm partnered with our National Environment Agency (NEA) for this project called Project Wolbachia. You see Wolbachia mosquitoes are another specie of mosquitoes, which are harmless and do not posess nor carry the dangerous dengue strain in their bodies.  Hence the objective of Project Wolbachia is to breed enough Wolbachia in the Labs at the MNC and later release them into the open air and allow them to a) fly around and b) breed with the Aedes mosquitoes.

The offspring of this new specie, will then be rendered harmless and behave like any mosquito The offspring is hopefully not able to transmit any dengue fever virus. When the Wolbachia mosquitos are bred in the Labs, they are then kept in refrigerated glass tanks at - 17 C. 

Multiple Level Polyethelene Containers - each level housing mosquitoes.

After enough of them are bred and raised, they will then be shepherded into containers such as the above. Each container contains 30 segments and each segment housing some 100 mosquitos (my guess). The execution of the project is high tech, like in some James Bond movie. These containers which are made of Polyethelene, will be mounted in refrigerated vans and these vans will ply a certain route through all the housing estates in Singapore.

At certain junctions or roads, the GPS will trigger the opening on the side of these vans automatically and one segment of the red container (there are 30 segments in total housed in a clear plastic cover) will be released and the Wolbachia mosquitoes will fly out and do their thing. 

The concern for the MNC was this :

The van is refrigerated and the mosquitoes are kept in the freezer at -17 C. Once they reach the designated location for release, the sliding door will automatically open and 35 - 38 C air will rush in. 

Hence after repeated drive bys, the containers will be experiencing a Temperatue Cycle of roughly 

- 17 C to + 35 C in a few minutes.

Over repeated locations, this will have an expansion (heat at 35C) and contraction (cold at -17C).

The concern that repeated Temperature Cycles will lead to a breakage of these containers which can be disastrous.

Hence, after discussing with QRA's experienced engineers, we devised a Temperature Cycle as shown below for them below : 

                                     Stress Screening Test Cycle suggested by QRA 

       Going Above and Beyond the Operational Temperature experienced by the  

                                                                  Containers. 

We suggested a Stress Screen Test, of roughly 200 cycles. Each cycle is 5 hours long, and the 200 cycles is expected to run for 1000 hours (or 200 multiplied by 5 hours) or 41.67 days. (42 days) 

The reason for the lower cold zone temperature and the higher hot zone temperature is the basis for the stress screen. Always subject the test samples to worse zones of temperature than they will be subjected to - in the end, only robustly designed samples will make it. 

Subject the test samples (containers) to extremes of temperatures, so that in test failures (cracks) are observed IN THE FACTORY and these weaknesses (material or otherwise) can be rectified before sending out the samples into the field.

The Stress Screen Test was carried out late last year and our MNC customer was very satisfied with the result.

All 3 containers passed the Stress Screen Test of 1000 hours. No cracks, delaminations or anything broken.

QRA has the distinction of making Singapore a safer place to live, work and play.

For more information ; please email 

E : qrasales@qra.com.sg

     mark@qra.com.sg

W : www.qra.com.sg.