Ammonium nitrate decomposes into gases including oxygen when heated
; however, ammonium nitrate can be induced to decompose
explosively by dtonation. Large stockpiles of the material
can be a major fire risk due to their supporting oxidation,
and may also detonate, as happened in the Texas City
disaster of which led to major changes in the regulations
for storage and handling.
There are two major classes of incidents resulting in
explosions:In the first case, the explosion happens
by the mechanism of shock to detonation transition.
The initiation happens by an explosive charge going
off in the mass, by the detonation of a shell thrown
into the mass, or by detonation of an explosive mixture
in contact with the mass. The examples are Kriewald,
Morgan, Oppau, Tessenderloo, and raskwood.
In the second case, the explosion results from a fire
that spreads into the ammonium nitrate itself , or to
a mixture of an ammonium nitrate with a combustible
material during the fire . The fire must be confined
at least to a degree for successful transition fro a
fire to an explosion a phenomeon known as "transition
fro a decomposition or deflagration", o Pure, compact
AN is stable and very difficult to initiate. However,
there are numerous cases when even imure AN didn't explode
in a fire.
Ammonium nitrat decomposes in temperatures aboves stable and will
stop decomposing once the heat source is removed, but in presence
of catalysts (combustible materials, acids, metal ions, chlorides
the reaction can become self-sustaining (known as self-sustaining
decomposition, This is well-known phenomenon with some types of
NPK fertilizers, and is responsible for loss of several cargo ships.
Significant accidental explosions
In a fire broke out in the amatol loading plant in Morgan,
New Jersey. Over pounds of explosives were present on
site, of tha up to and fire, bu did not detonate. a
heavy explosion of a mixture of ammonium nitrate and
ammonium sulfate detonated during attempts to break
up the caked pile with blasting charges (an operation
apparently performed several times before, with casualties
according to other sources, 50 or over 1000), occurred
in the city of Oppau on the grounds of BASF near Ludwigshafen
in Germany. Over 700 homes were destroyed, the plant
isappeared entirely and was replaced with a crater 50
ft deep and 250 ft in diameter, and the shock was felt
150 miles away. This was the largest man-made disaster
in German histoIn in Nixon, New Jersey, ammonium nitrate
was being recovered from amatol in order to be used
as a fertilizer, when a fire broke out. In April 4 and
The barrels were stored in a warehouse with varying
humidity for 6 years, so it is believed that they were
ignited by friction of the off-specification granular
AN was stored flat, separated bypartitions. About 2tons
is said to be involved in the explosion, resulting in
31 people dead and 2,442 injured, 34 of them seriously.
The blast wave shattered windows in 1.5-3 kilometer
distance and the resulting crater was 10 meters deep
and 50 meters wide. The exact cause remains unknown.
The material damage was estimated at 2.3 billion Euros.
The Ryongchon disaster inin North Korea is suspected to have a shipment
of ammonium nitrate involved, together with other explosives. Other
usesThe most common use of ammonium nitrate is in fertilizers.Ammonium
nitrate is also used in instant cold packs. In this use, ammonium
nitrate is mixed with water in an endothermic reaction, which absorbs
26.2 kilojoules of heat per mole of reactant.Due to its low temperature,
non-toxic decomposition products, it finds use in gas generator
applications such as airbags.Ammonium nitrate is also used in the
treatment of titanium ores.Ammonium nitrate fertilizer is also used
in the synthesis of methamphetamine.Ammonium nitrate is used in
survival kits mixed with zinc dust and ammonuim
The central nervous system represents the largest
part of the nervous system. Together with the peripheral
nrvous system, it has a fundamental role in the control
of behaviour.Since the strong theoretical influence
of cybernetics in the fifties, the is conceived as a
system devoted to information processing, where an appropriate
motor output is computed as a response toa sensory input.
Yet, many threads of research suggest that motor activity
exists well before the maturation of the sensory systems
and then, that the senses only influence behaviour without
dictating it. This has brought the conception of the
as an autonomous system.
The whole originates from the neural plate, a specialised region
of the ectoderm, the most external of the three embryonic layers.
During embryonic development, the neural plate folds and forms the
neural tube. The internal cavity of the neural tube will give rise
to the ventricular system. The regions of the neural tube will differentiate
progressively into transversal systems. Firs, the whole neural tube
will differentiate into its two major subdivisions: spinal cord
and brain . Cony the skull and the spinal cord by the vertebrae.
The rhombencephalon gives rise to the pons, the cerebellum and the
medulla oblongata, its cavity becomes the fourth ventricle. The
mesencephalon gives rise to the tectum, pretectum, cerebral peduncle
and its cavity develops into the mesencephalic duct or cerebral
aqueduct. The diencephalon gives rise to the subthalamus, hypothalamus,
thalamus and epithalamus, its cavity to the third ventricle. Finally,
the telencephalon gives rise to the striatum caudate nucleus and
putamen, the hippocampus and the neocortex, its cavity becomes the
lateral (first and second ventricles.
Layers
is composed of the epidermis and the dermis. Below these layers
lies the hypodermis, which is not usually classified as a layer
of skin.The outermost epidermis is made up of stratified squamous
epithelium with an underlying basement membrane. It contains no
blood vessels, and is nourished by diffusion from the dermis. The
main type of which make up the epidermis are keratinocytes, with
melanocytes and Langerhans cells also present. The epidermis can
be further subdivided into the following corneum, lucidum, granulosum,
spinosum, basale. Cells are formed through mitosis at the innermost
layers. They move up the strata changing shape and composition as
they differentiate and become filled with keratin. eventually reach
the corneum and become sloughed off. This process is called keratinization
and takes place within about 30 days. This layer of skin is responsible
for keeping water in the body and keeping other harmful chemicals
and pathogens out.
Blood capillaries are found beneath the epidermis,
and are linkedarteriole and a venule. Arterial shunt vessels may
bypass the network in ears, the nose and fingertips.The dermis lies
below the epidermis and contains a number of structures including
blood vessels, nerves, hair follicles, smooth muscle, glands and
lymphatic tissue. It is made up of loose connective tissue otherwise
called areolar connective tissue - collagen, elastin and reticular
fibres are present. Erector muscles, ed between the hair papilla
epidermis, can contract, resulting in the hairfibre pulled upright
and consequentially goose bumps. The main cell types are fibroblasts,
adipocytes and macrophages. Sebaceous glands are exocrine glands
which produce sebum, a mixture of lipids and waxy substances: lubrication,
water-proofing, softening and antibactericidal actions are among
the many functions of sebum. Sweat glands open up via a duct onto
the skin by aThe dermis can be split into the papillary and reticular
layers. The papillary layer is outermost and extends into the dermis
to supply it with vessels. It is composed of loosely arranged fibres.
Papillary ridges make up the lines of the hands. The reticular layer
is more dense and is continuous with the hypodermis. It contains
the bulk of the structures . The reticular layer is composed of
irregularly arranged fibres resists stretching.The hypodermis is
not part of the skin, and lies below the dermis. Its purpose is
to attach the skin to underlying bone and muscle as well as supplying
it with blood vessels and nerves. It is made up of loose connective
tissue and elastin. The main cell types are fibroblasts, macrophages
and adipocytes
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