PURIFIED WATER AND HOT WATER
A variety of contaminants and
impurities may be present in water supplies. Laboratory grade
water is water has had impurities such as microorganisms,
particulates, dissolved ionized or non-ionized solids and
gases as well as endotoxins, pyrogens, DNase and RNase to make
it suitable for use in the laboratory. Pure water is a
necessity in all laboratories, though different applications
call for different degrees of purification. Broadly speaking,
there are three different grades of laboratory water (four
using the standards for laboratory water as defined by the
American Society for Testing and Materials). These grades of
lab water being designated as types one through four.
Type 1 water is ultrapurified
water which has a nearly nonexistent level of particulate
matter, bacteria and other microorganisms, organic carbon,
endotoxins, pyrogens and other contaminants. Type 1 laboratory
grade water is typically produced by deionization,
distillation or osmosis before undergoing further
purification. This grade is also referred to as analytical
grade water and is used for applications including in vitro
fertilization, HPLC, ion chromatography and tissue culture.
Type 2 water contains very low
amounts of colloids, organic and inorganic impurities; low
enough to make this grade usable in trace analysis, atomic
absorption spectrometry and other analytical applications
whose sensitivity demands a high degree of water purity. Type
2 water can be produced by purifying potable water (such as
tap water) using reverse osmosis in conjunction with
distillation, ion exchange or multiple distillation.
Type 3 water is used for
preparing reagents in solutions, preparing chemical buffers
and a range of wet chemistry work and is the standard water
used for analytical purposes in laboratories. This general
grade of laboratory water is also used in microbiological
studies and preparing nutrient media for cell culture. Type 3
water may be produced through commercially available water
purification equipment which uses several different
purification methods or by double distillation.
Laboratory grade water may be
produced by a number of methods: Filtration technologies
including reverse osmosis, nanofiltration, ultrafiltration,
microfiltration and particle filtration may all be used to
remove particulates and other contaminants to produce water
which is pure enough for laboratory use. Filtration is often
the first step in producing type 1 and 2 water.
WET VS. DRY CLEANING
Advantages and Disadvantages of
Each Dry cleaning is considered a "surface clean." In other
words, it doesn't clean as deeply as a wet clean does. The
advantage of this method is that it's faster. With a wet
cleaning, you may need to wait anywhere from 8 to 12 hours for
the solution to dry. And so that is also the potential
downside - it does take a little longer. The advantage, as
mentioned, is that it's more forceful and more thorough, and
so the wait is often worth it.
Typical Cleaning Process Most
professional cleaners would use something similar to the
following process outlined below. First they survey the area
to be cleaned to understand the layout of the area and the
type of dirt and stains they will be dealing with.
Next they vacuum the area to remove as much "easy" dirt as
After vacuuming, they pre-condition the carpet with a
specialized cleaning solution. This emulsifies the suspended
dirt and biomaterials.
Next they agitate the areas
that receive the most amount of foot traffic. This serves to
loosen the compacted dirt.
After agitation, they rinse the cleaning solutions applied in
Step 3. This leaves the carpet fibers residue free. If there
are stubborn stain spots, they then treat these areas with
specialized stain removers. If necessary, these areas are left
to "dwell" for a time so that the spot removers can really do
their work. When the proper amount of time has passed, the
removal solutions are rinsed from the carpet.
Read and learn about a wide variety of
topics, ranging from guidelines relating to the home cleaning
products you choose, to the impact of your choices on your health
and the environment.