Design of an Adhesive Hook

these types of Adhesive hooks are very popular. why the hook is at the bottom?

the hooks are designed in this way because it should withstand peeling stress. the adhesive is having a peeling strength. if the stress overcome this strength it will comes out from the wall. consider the side view of two hooks. the direction of force on the hook is shown.

in the second case its very easy to overcome the peeling strength because of the position of the hook at top. from the next figure it will be clear.

this is the reason to keep the hook at the bottom. here peeling stress will be more. if the hook is at bottom it will compress the adhesive layer and because of that peeling stress will be less. so it won't comes out from the wall very easily.

soap dispenser

 

two different soap dispensers are shown here.
can you identify some advantages and disadvantages of each soap dispenser?
which design is better?

How to harvest rain water?

                in the traditional way the rain water is harvested in a Ferro cement tank or plastic tanks. water collected from the rooftop is filtered and then stored in tank. This tank normally will be in the ground level or underground. water is pumped to the overhead tank using a pump when ever required. normally water collect during rainy season and stored for summer.




of course this is a good idea in rain water harvesting. but is there a better way to make it more efficient?

yes.. of course..

most of the houses are using overhead tank on the terrace or on the roof from which water is supplied through pipes. if we analyse the rain water harvesting cycle, first water from the roof flowing down to the tank through the filter unit. this is then pumped back to the overhead tank by a pump.

instead if the water from the rooftop collect first in the overhead tank after filtering.
then the overflowing water can be collected in the underground tank.
the advantage is during rainy season no energy is required for pumping water into the overhead tank.

Problem with Drinking water can Pump

this is a very popular "water can pump". this is very useful since the water can is very heavy to lift. 

but one of the main problem of this pump is when the water level decrease it fails to pump or too many presses are required to pump water.

One reason is, air is leaking through the tightening portion, which is loosened due to the repeated pressing action.

Suggest and Design a solution for the problem for this pump or design a new mechanism for pumping out the water from bottles

Clock Design

mechanical clocks are now antique pieces. compared to the modern digital watches it's interface is very simple. only numbers from 1 to 12 to show the time.

here in the picture you can see a mechanical alarm clock. in this, can you tell the significance of the some letters along with the numbers. 

is it indicating anything?

Actually these letters are "BANK OF COCHIN". 

Is it a good way of representing something? what do you think.