Idea of Open roof type for swiftlet house

perfect example of open roof type for swiftlet entrance

Humidity and air density

Humidity and air density
Most people who haven't studied physics or chemistry find it hard to believe that humid air is lighter, or less dense, than dry air. How can the air become lighter if we add water vapor to it?

Scientists have known this for a long time. The first was Isaac Newton, who stated that humid air is less dense than dry air in 1717 in his book, Optics. But, other scientists didn't generally understand this until later in that century.

To see why humid air is less dense than dry air, we need to turn to one of the laws of nature the Italian physicist Amadeo Avogadro discovered in the early 1800s. In simple terms, he found that a fixed volume of gas, say one cubic meter, at the same temperature and pressure, would always have the same number of molecules no matter what gas is in the container. Most beginning chemistry books explain how this works.

Imagine a cubic foot of perfectly dry air. It contains about 78% nitrogen molecules, which each have a molecular weight of 28 (2 atoms with atomic weight 14) . Another 21% of the air is oxygen, with each molecule having a molecular weight of 32 (2 stoms with atomic weight 16). The final one percent is a mixture of other gases, which we won't worry about.

Molecules are free to move in and out of our cubic foot of air. What Avogadro discovered leads us to conclude that if we added water vapor molecules to our cubic foot of air, some of the nitrogen and oxygen molecules would leave — remember, the total number of molecules in our cubic foot of air stays the same.

The water molecules, which replace nitrogen or oxygen, have a molecular weight of 18. (One oxygen atom with atomic weight of 16, and two hudrogen atoms each with atomic weight of 1). This is lighter than both nitrogen and oxygen. In other words, replacing nitrogen and oxygen with water vapor decreases the weight of the air in the cubic foot; that is, it's density decreases.

Wait a minute, you might say, "I know water's heavier than air." True, liquid water is heavier, or more dense, than air. But, the water that makes the air humid isn't liquid. It's water vapor, which is a gas that is lighter than nitrogen or oxygen. (Related:Understanding water in the atmosphere).

Compared to the differences made by temperature and air pressure, humidity has a small effect on the air's density. But, humid air is lighter than dry air at the same temperature and pressure.

MAD COW OR LEMBU GILA DISEASE

Bovine spongiform encephalopathy (BSE) — commonly referred to as “mad cow disease” — is a transmissible spongiform encephalopathy (TSE) that affects cattle. BSE first was  described in cattle in the United Kingdom (U.K.) in 1986 but has been found in an additional 24 countries since that time. BSE cases in countries outside the U.K. appear to be a result of importation of live cattle that were harvested, rendered and fed back to ruminants, or importation of contaminated meat and bone meal derived from BSE-infected U.K. cattle for use as a protein supplement in cattle feed. As highlighted by the assessment of geographical BSE risk in Europe however, on behalf of the European Commission, most of the primary cases arising from such importations were never recognized. With few exceptions, cases were usually identified only after further recycling in the importing country, a decade or more after BSE was probably first introduced.

It initially was thought that, unlike some other TSE such as scrapie in sheep, there was only one strain of the disease-causing agent (prion) that caused BSE. In recent years evidence has been mounting that, in addition to classical BSE, two previously unrecognized types of BSE exist, although at an extremely low level.

Something that you should read

mud swallow chicks

this is we name swiftlet

this one mud swallow

this is white swiftlet nest 

  

Being an expert in swiftlet farming, I would like to give a few pointers.

The species Aerodramus fuciphagus do not litter their droppings. Their droppings are only within the birdhouse. Extensive droppings in many towns are not from these swiftlets but from mud swallows that make their nest underneath shophouses.

Indeed, swiftlets are hygienic and do not mix with other birds. The moment they fly out of the bird-house, they will not touch the ground until they return to the bird-house. Swiftlets also prey on harmful insects, like fruit flies etc, and can increase the yield of farmers and reduce the use of pesticides. They are natural pest control agents.

However, in the long term, it is important that swiftlet houses are not located in shop­houses in town centres due to aesthetics and noise pollution. They should be stand-alone units within agricultural areas.

As swiftlet farming is now increasingly seen as a financial gold mine, there are a few pointers potential investors must understand.

One disturbing trend is the development of huge bird-house complexes in one location. These are sold as units to potential buyers on the claim that these bird-houses will be filled with birds within a short time.

It is very unlikely that such huge bird-houses of hundreds of units can be filled within a short time. It will take 10 to 20 years or more for these massive bird-houses to be filled due to the slow natural population growth of the swiftlets in that particular locality.

As such, potential investors should make in-depth studies and consult experts in swiftlet farming before investing as the failure rate is more than 80%. The million ringgit investment may yield zero returns.

Apart from that, there are other quick-get-rich schemes using swiftlet farming as a front for their scam. Swiftlet farming entails a low initial return of one to five years, peaking only in the seventh to 10th year.

As such, it is impossible for the operators to give immediate 3% to 5% returns per month.