Thursday January 9, 2014

Day 35..

Our practical session this morning saw us having a go at gas welding - this was another first for me! Also called oxyacetylene welding, this process uses fuel gases and oxygen to weld two pieces of metals into one. A welding torch is used to weld the metal by being supplied by oxygen (usually a black bottle/pipe) and acetylene (a maroon coloured bottle/pipe). The welding happens when two pieces are heated to a temperature that produces a shared pool of molten metal. The molten pool is then supplied with additional metal called filler which acts as the binding material.

We were given a safety brief and discussed the correct way to turn on all the equipment - for this exercise the gas and oxygen bottles were in another area with pipes leading down to each workstation but we turned each supply on at the regulator and then adjusted the pressure regulators accordingly. With a small nozzle fitted to the torch, the gas is turned on (ever so slightly) and then lit with a gas lighting device (never a lighter) once the flame is turned down with a little black smoke then the oxygen is turned on to create the blue triangle flame - which is perfect to create the heat required. A tip is to fuse both ends of the pieces together first then work your way along from one way to the other. While the torch is moved gradually across to create the pool in one hand, in the other hand the filler is heated and used to bind the pieces together. Quite tricky to master but I did have a good second run when I wasn't flapping my arms too much and glided across the area, while having a better view of the working area.

This afternoons classroom lessons began with vaccinations and the main types used in sheep husbandry - when they are used and for what. In order to be start the vaccination process it is best to start with the immune system as it is a vaccinations job to stimulate the recipients immune system developing adaptable immunity to a pathogen (virus, or microorganism that can cause a virus or disease).

A good way to think of the immune system is by using the following table (we were split in to groups  and had to determine the correct flow):

Active-
               Natural-
Passive-
                                        Adaptive                  
Active-
              Artificial-
Passive-                                                  = immunity
                                   
                         
                                       Innate

As we have another assignment coming up, we also recapped on diseases: the main to affect sheep and cattle, the causes and effects and what if any harm to humans!