Archive for the ‘Engineering’ Category

Lack of Posting

March 28, 2011 Leave a comment

Repaired shoulderI apologise to those of you who regularly visit this blog, hoping to find a new post.

But, following a car accident last year, I am undergoing treatment for the injuries received, the latest being the repair of one of the major muscles in my shoulder. Prior to this latest surgical intervention, I had my wrist repaired, involving a bone graft and a pin.

I hope that I will be able to resume posts when I have the use of both arms again.

Categories: Engineering

The Kids Cook Dinner

January 4, 2011 Leave a comment

During my last visit to Kenya, I was at a loose end, so thought it might be a good idea to introduce some of my cooking methods to my Kenyan friends.

Of  course, the first potential problem was to find the ingredients that I am used to. In the event, all but cheese was readily available and I found that Nakumatt has a cheese counter where they sell cheddar which is just about acceptable. So, macaroni cheese is was going to be. The second problem is that I am not used to cooking a meal for eight on a single gas ring.

Benta (8) and Esther (13) were to be the cooks and I would guide them, but everyone, kids and adults alike all crowded around the single burner gas stove to watch, and in the case of the children, sneak a few bits of cheese from the chopping board!

After cooking the macaroni and storing it in a hot pot, the sauce was made, with much fussing around (and dipping in of fingers to taste it).

When everything was ready, the meal was served, pasta first then the sauce over the top. I am happy to report that it was rather popular.

I also introduced some herbs/spices into the household, the first being ground black pepper. Unfortunately, this was carried up by the steam from the cooking and invariably straight up the nose of whoever was cooking, causing a sneezing fit!

I eventually found black peppercorns in a grinder, which solved that problem.

Goat meat tenderises nicely when marinated in Guinness for 30 or so minutes.

I showed the kids how to make rice crispies chocolate cakes. Unfortunately, these lasted only about 5 minutes.

Still, the kids were happy and I hope I helped with varying the usually diet a bit.

On Anaerobic Digesters and CO2

December 20, 2010 3 comments

Regular readers will know that we built a prototype digester last year. It was relatively successful, but not very efficient due to the design, which was based around cost rather than gas production.

It was a proof-of-concept model.

Since then, I have designed, but not built models that should work a lot better, and I have also done some reading on the subject, since I can do little else with my wrist in plaster.

One thing that I found out recently – the gas produced is mainly methane [CH4], but there is a lot of carbon dioxide [CO2] in the mix. This could prove a bit of a problem as CO2 is, of course, inert and is even used in fire extinguishers, not the sort of gas one would want in the supply to a burner of some sort.

The answer, of course, is to clean the gas to remove at least most of the CO2

I believe that passing the CH4/CO2 mix through water does clear out the CO2, leaving a much purer gas fuel.

There is also the possibility of the fuel gas containing sulphur and passing the gas through a stainless steel scrubber will remove this.

However, anaerobic digester design, at personal/small community lever, is a very inexact science. Lots of people are building them, some are successful, others less so. There is a plethora of information on the web, some of it contradictory, so it is a very confusing field.

So, is there anyone out there with experience of building digesters who can verify (or otherwise) the necessity/efficiency of CO2 and sulphur removal?

You input would be most helpful and time saving.

Malaria and the Senses

This blog is categorised as “Curiosity in a field I know nothing about”

As my regular readers will know, we have a deaf child at the Twiga Centre, Simon, who is around 8 years old. As a baby of about 5 months, he contracted malaria and as a result [?] became deaf. Consequently, he has never learned to talk.

While I am wasting away in the UK, I am looking for ways that we may be able to help Simon; top of the list is to see if he responds to hearing aids, and I have received several from well-wishers.

But, my curiosity is asking me questions that I cannot answer. Why does malaria affect hearing (or sight, come to that)? Does it attack the mechanical bits in the ear itself, does it damage the nerves between the ear and the brain, or dies it damage the brain itself? Or, is there no one cause of deafness after malaria?

Having no knowledge of medical matters, tropical diseases and their effects, or the workings of the brain, I set about trying to work this out logically.

I only know of two people who have had adverse effects to their senses after contracting malaria, Simon, who has lost his hearing, and a Twitter friend, whose sight was severely affected after contracting the disease.

As far as I know, sight and hearing are not connected, so it would seem logical that it is a part of the brain that is affected by the illness rather than the primary organs themselves.

If this is the case, will a hearing aid help Simon? Is there any treatment, however intrusive, that could restore his hearing? I need to know.

So, I put out a plea to the doctors and hearing specialists who read blogs, who Tweet, or who stumble over this blog by other means Please can you satisfy my curiosity and possibly help this boy to regain some form of hearing, and eventually the ability to talk.

Categories: Engineering

Methane -v- wood/kerosene/charcoal

May 13, 2010 3 comments

Even if KCIS could design a very cheap anaerobic digester, would Kenyan women adopt it as a cooking fuel?

Wood and charcoal are traditional fuels, and I believe that Kenyans follow their traditions unless they are given a very good reason not to.

So, if KCIS did develop a very cheap anaerobic digester, would anyone use it?

OK, dear reader, please discuss!

More on Anaerobic Digesters

May 10, 2010 3 comments

KCIS has published its various designs for anaerobic digesters on their website.

All the designs can be modified to suit local needs, and we believe that the drawings are good enough for anyone to be able to build their own digester.

Details and pros and cons for each design is also published.

2-drum anaerobic digester

Two-Drum Anaerobic Digester

I’ve got GPS!

May 8, 2010 2 comments

I acquired a satnav or GPS at Christmas. I wanted a particular make, apparently the only make that is compatible with a South African digital map organisation, T4A, which is steadily mapping the whole of Africa, but this make is more expensive than the others, so I was forced to get the base model – no matter.

So I happily played around with it, pressing the various touch-screen buttons, and then eventually read some of the user manual. This is my usual practice, reading the manual after playing with a gadget. That is, if I ever read the manual at all.

Anyway, this satnav has a facility to enter a place by its longitude and latitude coordinates.

‘Oh what fun,’ I thought, being a bit of a nerd when it comes to playing with gadgets.

I opened up GoogleEarth on my computer and found the coordinates for the main junction in Kisii, called, funnily enough, the Junction.

I pumped the coordinates into the satnav. It thought for a while and then invited me to either look at the map or start my journey. I was a little surprised.

I elected to look at the map and, to my astonishment, it showed the confluence of the A1 and B3 roads in Kisii.

Kisii Junction

‘OK,’ I thought, if you are so clever, plan me the route!

The savnav thought for quite a long time before announcing that the route was 6,392 miles and would take 127 hours and 44 minutes. It displayed a map comprising Europe and most of Africa with a magenta line wiggling across it. I was astounded. I checked the system set-up which confirmed that the only maps loaded were for UK and Northern Ireland.

From Hampshire to Kisii

The next thing for a nerd to do would be to check the route. It took me through Europe to Istanbul, Turkey, on to Ankara, then Damascus. This is where it got a bit fuzzy, through Jordan and into Israel.

From there it took me down the west bank of the Red Sea, traversing Egypt north-south, into Sudan, Ethiopia, and then Kenya, where I started to recognise town names, Marsabit, Isiolo, Nanyuki, Nakuru, Kericho and finally, Kisii.

To me, this was impressive. I saved the coordinates for Kisii Junction and wondered what other places I should put in.

I eventually decided to enter the salient points of the route from Nairobi to Kisii, there are a couple of junctions I always nearly miss when I am driving, particularly onto the B3 from the A104, and a little later where the B3 hangs a left off the Old Naivasha Road at Mai Mahiu. From there on, it is plain sailing all the way to the junction with the C23, near Sotik.

I put in Keroka, as I have a friend who lives there. I entered the coordinates for Kisumu, Kakamega and Bungoma, all places I have driven through or to, and probably will again.

Now all I have to do is to find out if it actually works in Kenya. There is not reason why it shouldn’t. The satellites are up there, just looking for my little satnav to talk to.

I may get a chance later this year, when I hope to go to Kenya to continue working on my anaerobic digester, drum up some more business and “network” with organisations in the field.

My original intention, when choosing this particular make of satnav was to also buy the CD of East African maps from Tracks4Africa and load it. But will I need to?

OK, I don’t have all the off-road tracks and minor roads on my gadget, but do I really need them? I am not going on safari. If I do hire a car to go somewhere, I will want to get there quickly and safely – and not get lost like I did on my last trip.

I expect that I will eventually get the CD and all the software that comes with it. After all, I am a bit of a nerd, but I will take my satnav with me to Kenya and see just what it has to offer me in the meantime.

And I also hope that GoogleEarth will reinstate the Tracks4Africa overlay that used to be available.

This blog was originally posted at Baba Mzungu

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