In the morning, we set up a makeshift solar cooker with a WAPI inserted at 9:00 a.m. We also inserted WAPIs into a large and a small SODIS bottles and put these onto the roof, just as a control. Mike suggested flattening out the cardboard box and then pasting aluminium foil to its interior (we so far had been taping aluminium foil, which became very ruffled in the process). This was the way Mike saw done in Solar Connections Association. We attempted this on half a cardboard box before we ran out of glue, unfortunately, so this method was not tested today (we needed to get more glue from Masaka).
Kevin went to all the water sources in Ddegeya (BH4, P1, P2, the two ponds beside BH1, BH6, and P3) and took water samples from these. These were subsequently plated on Petrifilm for microbial analysis. In the meanwhile, Dave and Mike were going to wash more sand, but Joseph and Eddie dropped by. Eddie had agreed to be a test household for the slow sand filter, so Dave and Mike showed them the steps in sifting and then washing sand.
Near noon, Dave and Mike went to Masaka to get more supplies---namely, some water-based glue for gluing aluminium foil onto cardboard boxes, some more friendly black paint, a paint brush, and some grocery supplies that the clinic requested. Dave and Mike were unable to obtain putty glue or some transparent cover (e.g. glass or Plexiglas) for the solar cooker. In the meanwhile, Kevin spent entire afternoon sifting sand from the fine/intermediate-sized pile in order to just get the finest sand for washing, with the immense help of some children.
Now about the solar cooker. For most of the time, the black-painted container felt very hot to touch, and when the water was removed, one could only hold his finger in the water for about 2-3 seconds, suggesting that the water temperature was at least 60 C. We plated water from the solar cooker on coliform and enterobacteria Petrifilms and will see the results in two days.
Unfortunately, the solar cooker did not have a favourable result in terms of WAPI. The WAPI tube was checked at about 12:30 p.m., 2:45 p.m., 3:30 p.m., and 4:15 p.m. (finish time for the solar cooker test), and the wax therein failed to melt (melting indicates pasteurization). We are not sure if this null result is due to our makeshift setup (with all crumpled aluminium foil), due to too ambitious amount of water (5 L in a small jerry can), or due to an occasionally cloudy day.
This disappointing WAPI result suggests that we should redesign our solar cookers a bit. So far we are limited by material. The cardboard boxes at our disposal have been difficult to make into an inner and an outer box typically required for a solar cooker. So this is why we started with a single-box configuration, in which the interior is lined with aluminium foil. Late in the afternoon, Kevin designed a setup in which an inner-outer box configuration is possible, with the material constraint that the inner box is way shallower than the outer box (and we did not really want to cut up the outer box before a design is finalised). The flaps of the outer box were turned inward, and some pieces of cardboard of the right size were wedged against the flaps, forming a support on which the much shallower inner box. The flaps, and much of the interiors of the inner and outer boxes were lined with aluminium foil (the inner box was cut open to glue the aluminium foil properly, but the outer box was not so important in terms of crimpled aluminium foil). Our only reservation is that the inner box might be too small to be very effective, but so far we have no other choices of inner boxes.
Tomorrow we also plan to test the original one-box configuration, but with the aluminium foil glued properly (instead of taped in an ad hoc manner). We just hope that the weather tomorrow will be fair. In the morning, we set up a makeshift solar cooker with a WAPI inserted at 9:00 a.m. We also inserted WAPIs into a large and a small SODIS bottles and put these onto the roof, just as a control. Mike suggested flattening out the cardboard box and then pasting aluminium foil to its interior (we so far had been taping aluminium foil, which became very ruffled in the process). This was the way Mike saw done in Solar Connections Association. We attempted this on half a cardboard box before we ran out of glue, unfortunately, so this method was not tested today (we needed to get more glue from Masaka).
Kevin went to all the water sources in Ddegeya (BH4, P1, P2, the two ponds beside BH1, BH6, and P3) and took water samples from these. These were subsequently plated on Petrifilm for microbial analysis. In the meanwhile, Dave and Mike were going to wash more sand, but Joseph and Eddie dropped by. Eddie had agreed to be a test household for the slow sand filter, so Dave and Mike showed them the steps in sifting and then washing sand.
Near noon, Dave and Mike went to Masaka to get more supplies---namely, some water-based glue for gluing aluminium foil onto cardboard boxes, some more friendly black paint, a paint brush, and some grocery supplies that the clinic requested. Dave and Mike were unable to obtain putty glue or some transparent cover (e.g. glass or Plexiglas) for the solar cooker. In the meanwhile, Kevin spent entire afternoon sifting sand from the fine/intermediate-sized pile in order to just get the finest sand for washing, with the immense help of some children.
Now about the solar cooker. For most of the time, the black-painted container felt very hot to touch, and when the water was removed, one could only hold his finger in the water for about 2-3 seconds, suggesting that the water temperature was at least 60 C. We plated water from the solar cooker on coliform and enterobacteria Petrifilms and will see the results in two days.
Unfortunately, the solar cooker did not have a favourable result in terms of WAPI. The WAPI tube was checked at about 12:30 p.m., 2:45 p.m., 3:30 p.m., and 4:15 p.m. (finish time for the solar cooker test), and the wax therein failed to melt (melting indicates pasteurization). We are not sure if this null result is due to our makeshift setup (with all crumpled aluminium foil), due to too ambitious amount of water (5 L in a small jerry can), or due to an occasionally cloudy day.
This disappointing WAPI result suggests that we should redesign our solar cookers a bit. So far we are limited by material. The cardboard boxes at our disposal have been difficult to make into an inner and an outer box typically required for a solar cooker. So this is why we started with a single-box configuration, in which the interior is lined with aluminium foil. Late in the afternoon, Kevin designed a setup in which an inner-outer box configuration is possible, with the material constraint that the inner box is way shallower than the outer box (and we did not really want to cut up the outer box before a design is finalised). The flaps of the outer box were turned inward, and some pieces of cardboard of the right size were wedged against the flaps, forming a support on which the much shallower inner box. The flaps, and much of the interiors of the inner and outer boxes were lined with aluminium foil (the inner box was cut open to glue the aluminium foil properly, but the outer box was not so important in terms of crimpled aluminium foil). Our only reservation is that the inner box might be too small to be very effective, but so far we have no other choices of inner boxes.
Tomorrow we also plan to test the original one-box configuration, but with the aluminium foil glued properly (instead of taped in an ad hoc manner). We just hope that the weather tomorrow will be fair. In the morning, we set up a makeshift solar cooker with a WAPI inserted at 9:00 a.m. We also inserted WAPIs into a large and a small SODIS bottles and put these onto the roof, just as a control. Mike suggested flattening out the cardboard box and then pasting aluminium foil to its interior (we so far had been taping aluminium foil, which became very ruffled in the process). This was the way Mike saw done in Solar Connections Association. We attempted this on half a cardboard box before we ran out of glue, unfortunately, so this method was not tested today (we needed to get more glue from Masaka).
Kevin went to all the water sources in Ddegeya (BH4, P1, P2, the two ponds beside BH1, BH6, and P3) and took water samples from these. These were subsequently plated on Petrifilm for microbial analysis. In the meanwhile, Dave and Mike were going to wash more sand, but Joseph and Eddie dropped by. Eddie had agreed to be a test household for the slow sand filter, so Dave and Mike showed them the steps in sifting and then washing sand.
Near noon, Dave and Mike went to Masaka to get more supplies---namely, some water-based glue for gluing aluminium foil onto cardboard boxes, some more friendly black paint, a paint brush, and some grocery supplies that the clinic requested. Dave and Mike were unable to obtain putty glue or some transparent cover (e.g. glass or Plexiglas) for the solar cooker. In the meanwhile, Kevin spent entire afternoon sifting sand from the fine/intermediate-sized pile in order to just get the finest sand for washing, with the immense help of some children.
Now about the solar cooker. For most of the time, the black-painted container felt very hot to touch, and when the water was removed, one could only hold his finger in the water for about 2-3 seconds, suggesting that the water temperature was at least 60 C. We plated water from the solar cooker on coliform and enterobacteria Petrifilms and will see the results in two days.
Unfortunately, the solar cooker did not have a favourable result in terms of WAPI. The WAPI tube was checked at about 12:30 p.m., 2:45 p.m., 3:30 p.m., and 4:15 p.m. (finish time for the solar cooker test), and the wax therein failed to melt (melting indicates pasteurization). We are not sure if this null result is due to our makeshift setup (with all crumpled aluminium foil), due to too ambitious amount of water (5 L in a small jerry can), or due to an occasionally cloudy day. Incidentally, just after taking off the water and finding out that the WAPI failed to melt, Kevin threw in a second WAPI. This one melted a little, yielding some powder at the bottom of the WAPI tube. We are currently not sure what this means. As expected, the WAPIs in the SODIS bottles did not do anything interesting.
This disappointing WAPI result suggests that we should redesign our solar cookers a bit. So far we are limited by material. The cardboard boxes at our disposal have been difficult to make into an inner and an outer box typically required for a solar cooker. So this is why we started with a single-box configuration, in which the interior is lined with aluminium foil. Late in the afternoon, Kevin designed a setup in which an inner-outer box configuration is possible, with the material constraint that the inner box is way shallower than the outer box (and we did not really want to cut up the outer box before a design is finalised). The flaps of the outer box were turned inward, and some pieces of cardboard of the right size were wedged against the flaps, forming a support on which the much shallower inner box. The flaps, and much of the interiors of the inner and outer boxes were lined with aluminium foil (the inner box was cut open to glue the aluminium foil properly, but the outer box was not so important in terms of crimpled aluminium foil). Our only reservation is that the inner box might be too small to be very effective, but so far we have no other choices of inner boxes.
Tomorrow we also plan to test the original one-box configuration, but with the aluminium foil glued properly (instead of taped in an ad hoc manner). We just hope that the weather tomorrow will be fair. Any other suggestions for making the solar cooker behave more efficiently?
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