chemistry online | video lectures online | Free education online is possible: February 2009

Clinker Microstructure

Author: mostafa

•10:18 AM

Clinker Microstructure
The microstructure or fabric of a clinker is also decisive when considering phenomena such as clinker grinding , cement hydration and hardening .

Microscopical appearance of clinker phase
1 – Alite ( C3S ) .
External Form Alite , the principal constituent of cement clinker , occurs as idiomorphic crystals , i.e sharp-edged crystals .
2 – Belite ( C2S ) .
External Form , round crystal form is the most characteristic shape of belite .

3 – Free Lime ( F.L ) .
Free Lime always appears as rounded spherical crystal .
4 – Aluminates .
Aluminates appear as cubic form .
5 – Ferrite .
Like aluminates appears as cubic form .
6 – Periclase .
Appears as idiomorphic crystal .
Influence of production condition on clinker microstructure
The microstructure of industrially product clinker is influenced by several process parameters :
a – Raw mix properties :
I – Chemical composition .
II – Fineness and mineralogy .
III – Homogeneity .
b – Fuel type .
c – Burning conditions :
I – Burning time / temperature .
II – Kiln atmosphere .
d – Cooling condition :
I – Rate of cooling .

Sulphate Resistance Cement – SRC Grade 32.5 R

Author: mostafa

•10:00 AM

SRC is defined as the hydraulic bonding grey fine powder which is the result from crushing a dry mi

x made of clinker and gypsum.
Adding and mixing water to it harden this grey fine powder, and this is what makes it resistant to water and able to bare compressive stresses, as well as resistant to sulphates that exist in soil, such as clay soil.
In this type of cement it is necessary to decrease the ratio C3A less than 3.5%, because this component reacts with Ca SO4, which exists in soil or water. The result of this reaction is called Etringite, which is aproximately 277% of the volume of C3A, and causes cracks that leads to concrete failures.
Part of the sulphate resistance cement composition is an adittion of Fe2O3 mixed with row materials. Fe2O3 facilitates the reduction of Etringite and increases C4AF, which does not have the property of expansioning volume; so it has higher resistance against sulphates.
Uses and applications:
It can be used in all concrete constructions such as reinforced concrete foundations, sewage drainage tanks, bridge foundations, piles...which are exposed to be directly affected by sulfates.
It can also be used in sewage concrete pipes and lining steel pipes.
Shelf time:
6 weeks, since the production date.
Safety recommendations:
It is recommended to follow the coming instructions:
Avoid the contact of the cement with the eyes and the skin since it may cause allergic reaction.
Use gloves and glasses to protect hands and eyes in case of spry applications, or manual mixings.
It is no poison, according to all international specification for safety and health.
Packing:
Bags: 50 Kg/bag
Jumbo plastic bags:500 Kg/bag1000 Kg/bag1500 Kg/bag
It is also available in bulk
Storage:
It is recommended to follow the coming instructions:
Storage should be done in a dry place and away from ground moisture.
It is preferable to store it on wooden bases.
Cement should be covered to avoid the rain.
It is recommended not to pile up any more than ten bags, some on others.
How to clean the cement remains of the used tools:
Before setting: by using clean water.
After setting: by using mechanical methods.
Environment concept
It is advised and recommended to follow local environmental instructions.

Premium Brand – El Mohandes

Author: mostafa

•10:43 AM

El Mohandes cement is a very special formula of Ordinary Portland cement that gives relatively delayed initial setting time, early compressive strength for concretes, and moderate heat of hydration for concrete and mortar
Generally, El Mohandes is recommended for mixing concrete in hot weather and suitable to be used in ready mix concrete plants, factory precast concrete elements, and prefabricated concrete units.
Uses and applications:
It can be used in all types of constructions, which need high early compressive strength, such as bridges, tunnels, prefabricated floor, and precast concrete...
Advantages:
1. It gives relatively high early compressive strength after7 days.
2. It gives high final compressive strength (28 days).
3. It gives a relatively delayed setting time and reduces the ratio of concrete normal and super plasticisers admixtures (this admixture is used to delay initial setting time of concrete and give more workability).
Shelf time:
3 months, from the production date.
It is recommended to retest the cement after 6 weeks.
Safety recommendations:
It is recommended to follow the coming instructions:
Avoid the contact of the cement with the eyes and the skin since it may cause allergic reaction.
Use gloves and glasses to protect hands and eyes in case of spry applications, or manual mixings.
Packing:
Bags: 50 Kg/bag
Jumbo plastic bags:500 Kg/bag1000 Kg/bag1500 Kg/bag
It is also available in bulk
Storage:
It is recommended to follow the coming instructions:
Storage should be done in a dry place and away from ground moisture.
It is preferable to store it on wooden bases.
Cement should be covered to avoid the rain.
It is recommended not to pile up any more than ten bags, some on others.
How to clean the cement remains of the used tools:
Before setting: by using clean water.
After setting: by using mechanical methods.
Environment concept

It is advised and recommended to follow local environmental instructions

Ordinary Portland Cement – OPC

Author: mostafa

•10:20 AM

Ordinary Portland Cement was the first cement to be produced all over the world, and the most po

pular one.
It was named “Portland” because of the similarity in shape and color with the cement material and limestone, which exists in Portland Island, in England.
It is defined as the hydraulic bonding grey fine powder which is the result from crushing a dry mix made of clinker and gypsum.
Adding and mixing water to it hardens this grey fine powder, which is known as the initial setting, and this is what makes it resistant to water and able to bare compressive stresses.
Uses and applications
It can be used in all concrete construction such as reinforced buildings, water tanks, roads, and any other building works, which are not subjected to sulphate effect.
It also can be used in relevant industries of the construction, as prefabricated, to produce hollow and solid blocks, tiles and railway line concrete supports.
Shelf time
3 months, from the production date.It is recommended to retest the cement after 6 weeks.
Safety recommendations
It is recommended to follow the coming instructions:
Avoid the contact of the cement with the eyes and the skin since it may cause allergic reaction.
Use gloves and glasses to protect hands and eyes in case of spry applications, or manual mixings.
Packing:
Bags: 50 Kg/bag
Jumbo plastic bags: 500 Kg/bag 1000 Kg/bag 1500 Kg/bag
It is also available in bulk.
Storage.
It is recommended to follow the coming instructions:
Storage should be done in a dry place and away from ground moisture.
It is preferable to store it on wooden bases.
Cement should be covered to avoid the rain.
It is recommended not to pile up any more than ten bags, some on others.
How to clean the cement remains of the used tools
Before setting: by using clean water.
After setting: by using mechanical methods.
Environment concept
It is advised and recommended to follow local environmental instructions.

Al Fanar Cement

Author: mostafa

•12:04 PM

A type of Portland cement that generates moderate quantity of heat of hydration and moderate sulphates and chloride salts resistance. The scientific concept of Al Fanar Cement is to comply with the standards of Modified Portland Cement Type II by reducing the final total content of Tri-Calcium Aluminates and Tri-Calcium silicate phases as it hydrates generating bigger quantity of heat of hydration.
Uses and applications
Generally, Al Fanar Cement is recommended for mixing concrete in the media of double exposure to sulphates and chloride ions such as substructures and superstructures subjected to seawater attack. Also it is suitable for concrete elements of large cross sections (mass concrete).
Advantages
1. Moderate heat of hydration that reduces cracks even in mass concrete.
2. Balanced moderate Resistance of sulphates and chlorides.
3. It gives relatively moderate early compressive strength after7 days.
4. It gives high final compressive strength (28 days).
5. It gives a relatively delayed setting time and may reduce the needed dosage of concrete admixtures.
Shelf time
3 months, from the production date. It is recommended to retest the cement after 6 weeks.
Safety recommendations
It is recommended to follow the coming instructions:
Avoid the contact of the cement with the eyes and the skin since it may cause allergic reaction.
Use gloves and glasses to protect hands and eyes in case of spry applications, or manual mixings.
Packing
Bags: 50 Kg/bag
Jumbo plastic bags:500Kg/bag 1000Kg/bag 1500 Kg/bag
It is also available in bulk.
Storage
It is recommended to follow the coming instructions:
Storage should be done in a dry place and away from ground moisture.
It is preferable to store it on wooden ballets.
Cement should be covered to avoid the rain.
It is recommended not to pile up any more than ten bags, some on others.
How to clean the cement remains of the used tools
Before setting: by using clean water.
After setting: by using mechanical methods.
Environment concept
Do not dispose of into water or soil so it is advised and recommended to follow local environmental instructions.

Three Main Stages in the Soap Making process

Author: mostafa

•2:00 PM

1. SAPONIFICATION :

The Batch Method
Semi Boiled Saponification for the production of medium quality soap is made by a simple mixing and heating process in a Crutcher (soap mixer) and is used for making small (1 to 5 tonnes) batches of laundry or household soap. Any impurities in the raw materials will be present in the finished soap and there is no wasted discharge to drain.
Fully Boiled Saponification for production of good to high quality soaps is made in kettles. This is the commonest form of soap making. It can be used for laundry soap or toilet soap. The Fully Boiled Soap is washed during the process to remove any impurities or glycerine. Batch size is typically 25 to 50 tonnes and 3 to 5 kettles are used. Typical plant outputs are 1 to 5 tonnes per hour. The fully boiled and washed soap (called neat soap) produces soap to international quality standards. Some wastes may need to be discharged to drain if glycerine is not recovered from these wastes (called lye).
The Continuous Process
Continuous Saponification is suitable for the production of all grades of soap up to the highest quality levels. This system is not suitable for production rates of less than 50 tonnes of soap per day. The system can be sized up to soap production rates in excess of 200 tonnes per day.
In the process, raw materials are accurately metered via a special pump to the saponification reactor. Following reaction, the neat soap is separated from the glycerine rich by-product of the reaction. The separation takes place in two main stages, firstly in the rotating disk column, secondly via centrifuge separation. The neat soap is pumped to storage, or directly to vacuum spray drying section.
Since glycerine is valuable, the plant will often include a glycerine recovery section to purify the recovered glycerine.
Continuous Neutralisation is a also a continuous process, but it is significantly simpler than the saponification process. The fatty raw materials in this process are fatty acids rather than palm oil (blends) or tallow.Once again raw materials are accurately metered to a neutralisation reactor. There is no by-product to the neutralisation process, therefore there is no separation stage. The neat soap is pumped to storage, or directly to vacuum spray drying section.

2. DRYING STAGE :

Chilling Roll Method
This process uses chilled rolls to dry the liquid neat soap into soap ribbons. The liquid soap is pumped onto chilled cooling rolls, and immediately solidifies. The solid soap is continuously scraped off the chilling roller as a ribbon or flake and drops into a wooden or plastic tray. When all the trays are full they are placed in racks or trolleys and moved into a Drying Room where they are left for a period to dry or cool.

Vacuum Spray Drying Method
The liquid neat soap is pumped through the heat exchanger and then it is sprayed into the v

acuum chamber. The water vapour is extracted by a vacuum system and the final water content of the soap is controlled by adjusting the heat exchanger temperature and the level of vacuum. Typical final moisture levels are 22 % moisture for laundry soap and 13 % for toilet soap.
The soap dries as it passes across the vacuum chamber and sticks to the internal surfaces. It is scraped off by a set of slowly rotating knives and falls into a plodder on which the vacuum spray chamber is mounted. The plodder continuously extrudes soap whilst maintaining the vacuum seal and can deliver noodles for toilet soap or a continuous extrusion for laundry bars.

3. FINISHING STAGE :

The finishing process varies whether the final product is Laundry Soap or Toilet Soap. The customer can choose between semi-automatic and fully-automatic levels of operation, both for individual machines or for complete production lines.

Polypropylene PP

Author: mostafa

•8:00 AM

Polypropylene PP

INTRODUCTION
Polypropylene (PP) is a linear hydrocarbon polymer, expressed as CnH2n. PP, like polyethylene and polybutene, is a polyolefin or saturated polymer. Polypropylene is one of those most versatile polymers available with applications, both as a plastic and as a fibre, in virtually all of the plastics end-use markets.
PROPERTIES

(Semi-rigid, translucent, good chemical resistance, tough, good fatigue resistance, integral hinge property, good heat resistance). Production of polypropylene takes place by slurry, solution or gas phase process, in which the propylene monomer is subjected to heat and pressure in the presence of a

catalyst system. Polymerisation is achieved at relatively low temperature and pressure and the product yielded is translucent, but readily coloured. Differences in catalyst and production conditions can be used to alter the properties of the plastic. PP does not present stress-cracking problems and offers excellent electrical and chemical resistance at higher temperatures. While the properties of PP are similar to those of Polyethylene, there are specific differences. These include a lower density, higher softening point (PP doesn't melt below 160oC, Polyethylene, a more common plastic, will anneal at around 100oC) and higher rigidity and hardness. Additives are applied to all commercially produced polypropylene resins to protect the polymer during processing and to enhance end-use performance.
GRADES AVAILABLE :
Three types of polypropylene are currently available. Each suits particular specifications and costing (although there is often some overlap).
Homopolymers
A General Purpose Grade that can be used in a variety of different applications.
Block copolymers
incorporating 5-15% ethylene, have much improved impact resistance extending to temperatures below -20oC. Their toughness can be further enhanced by the addition of impact modifiers, traditionally elastomers in a blending process.
Random copolymers
incorporate co-monomer units arranged randomly (as distinct from discrete blocks) along the polypropylene long chain molecule. Such polymers typically containing 1-7% ethylene are selected where a lower melting point, more flexibility and enhanced clarity are advantageous.

Applications of polypropylene

Author: mostafa

•1:27 PM

Applications of polypropylene
Polypropylene can be processed by virtually all thermoplastic-processing methods.
Most typically PP Products are manufactured by: extrusion blow moulding, injection moulding.
Flexible Packaging
PP is one of the leading materials used for film extrusion and has in recent years benefited versus cellophane, metals and paper on account of its superior puncture resistance, low sealing threshold and competitive price.

Consumer Products
Products classified in this sector are Housewares, Furniture, Appliances, Luggage, Toys, Battery Cases and other "durable" items for home, garden or leisure use.
Fibre
PP Fibre is utilised in a host of applications including tape, strapping, bulk continuous filament, staple fibres, spunbound, and continuous filament.
Industrial
PP is used to manufacture a range of Sheet, Pipe, Compounding and Returnable Transport Packaging (RTP). With the exception of RTP where Injection Moulding is used, extrusion dominates the conversion process used for these products. Some PP is utilised by the construction sector, most notable domestic drainage pipes.

Detergents and Soap

Author: mostafa

•9:00 AM

Detergents and soaps are used for cleaning because pure water can't remove oily, organic soiling. Soap cleans by acting as an emulsifier. Basically, soap allows oil and water to mix so that oily grime can be removed during rinsing. Detergents were developed in response to the shortage of the animal and vegetable fats used to make soap during World War I and World War II. Detergents are primarily surfactants, which could be produced easily from petrochemicals. Surfactants lower the surface tension of water, essentially making it 'wetter' so that it is less likely to stick to itself and more likely to interact with oil and grease.
Modern detergents contain more than surfactants. Cleaning products may also contain enzymes to degrade protein-based stains, bleaches to de-color stains and add power to cleaning agents, and blue dyes to counter yellowing.
Like soaps, detergents have hydrophobic or water-hating molecular chains and hydrophilic or water-loving components. The hydrophobic hydrocarbons are repelled by water, but are attracted to oil and grease. The hydrophilic end of the same molecule means that one end of the molecule will be attracted to water, while the other side is binding to oil. Neither detergents nor soap accomplish anything except binding to the soil until some mechanical energy or agitation is added into the equation. Swishing the soapy water around allows the soap or detergent to pull the grime away from clothes or dishes and into the larger pool of rinse water. Rinsing washes the detergent and soil away. Warm or hot water melts fats and oils so that it is easier for the soap or detergent to dissolve the soil and pull it away into the rinse water. Detergents are similar to soap, but they are less likely to form films (soap scum) and are not as affected by the presence of minerals in water (hard water).

Petrochemicals/Oleochemicals
These fats and oils are hydrocarbon chains which are attracted to the oily and greasy grime.
Oxidizers
Sulfur trioxide, ethylene oxide, and sulfuric acid are among the molecules used to produce the hydrophilic component of surfactants. Oxidizers provide an energy source for chemical reactions. These highly reactive compounds also act as bleaches.
Alkalis
Sodium and potassium hydroxide are used in detergents even as they are used in soap making. They provide positively charged ions to promote chemical reactions.

Author: mostafa

•1:40 PM

What is a surfactant?
A surfactant or surface active agent is a substance that, when dissolved in water, gives a product the ability to remove dirt from surfaces such as the human skin, textiles, and other solids.
In more technical terms:
(1)they enable the cleaning solution to fully wet the surface being cleaned so that dirt can be readily loosened and removed.
(2)they clean greasy, oily, particulate-, protein-, and carbohydrate-based stains.
(3)they are instrumental in removing dirt and in keeping them emulsified, suspended, and dispersed so they don't settle back onto the surface being cleaned.

Each surfactant molecule has a hydrophilic (water-loving) head that is attracted to water molecules AND a hydrophobic (water-hating) tail that repels water and simultaneously attaches itself to oil and grease in dirt. These opposing forces loosen the dirt and suspend it in the water. The mechanical agitation of the washing machine helps pull the dirt free. Surfactants are one of the major components of cleaning products and can be regarded as the 'workhorses': they do the basic work of breaking up stains and keeping the dirt in the water solution to prevent re-deposition of the dirt onto the surface from which it has just been removed. Surfactants disperse dirt that normally does not dissolve in water. As anyone who uses oil based dressings in the kitchen knows, oil and water do not mix unless shaken vigorously in the bottle. They separate almost immediately afterwards. The same is true when washing your dishes or clothes. With the addition of surfactants, oil, which normally does not dissolve in water, becomes dispersible and can be removed with the wash water.

What does a surfactant actually do?

Surfactants are also referred to as wetting agents and foamers. Surfactants lower the surface tension of the medium in which it is dissolved. By lowering this interfacial tension between two media or interfaces (e.g. air/water, water/stain, stain/fabric) the surfactant plays a key role in the removal and suspension of dirt. The lower surface tension of the water makes it easier to lift dirt and grease off of dirty dishes, clothes and other surfaces, and help to keep them suspended in the dirty water. The water-loving or hydrophilic head remains in the water and it pulls the stains towards the water, away from the fabric. The surfactant molecules surround the stain particles, break them up and force them away from the surface of the fabric. They then suspend the stain particles in the wash water to remove them.

What does a surfactant "look like"?

A tadpole! A surfactant consists of a hydrophobic (non-polar) hydrocarbon "tail" and a hydrophilic (polar) "head" group. This appearance is key to its behaviour. The dirt-loving or hydrophobic tail absorbs to the oil and grease in dirt and stains.

Are surfactants of natural or synthetic origin ?
They can be either. Surfactants from natural origin (vegetable or animal) are known as oleo-chemicals and are derived from sources such as palm oil or tallow. Surfactants from synthetic origin are known as petro-chemicals and are derived from petroleum. Having the flexibility to use both oleochemical and petrochemical surfactants allows our formulators to create products that maximize the value in the bottle of detergent, so to speak, by optimizing cleaning ability under a variety of laundry conditions while keeping the price low in the current market. These days, our formulation scientists focus quite a lot on developing detergents that perform well at lower wash temperatures. This approach will continue to yield energy savings during the consumer use phase, hence a reduction of CO2 emissions. Surfactants also have an important role in our body, where they are used to reduce surface tension in the lungs. The human body does not start to produce lung surfactants until late in foetal development. Therefore, premature babies are often unable to breathe properly, a condition called Respiratory Distress Syndrome. Untreated, this is a serious illness and is often fatal, but administration of artificial surfactants virtually eliminates this health problem.

Are there different types of surfactants?
There is a broad range of different surfactant types, each with unique properties and characteristics: the type of dirt and fabric on which they work best, how they can cope with water hardness. Detergents use a combination of various surfactants to provide the best possible cleaning results. There are four main types of surfactants used in laundry and cleaning products. Depending on the type of the charge of the head, a surfactant belongs to the anionic, cationic, non-ionic or amphoteric/zwitterionic family.

Anionic surfactants

In solution, the head is negatively charged. This is the most widely used type of surfactant for laundering, dishwashing liquids and shampoos because of its

excellent cleaning properties and high . The surfactant is particularly good at keeping the dirt away from fabrics, and removing residues of fabric softener from fabrics.

anionic surfactants are particularly effective at oily soil cleaning and oil/clay soil suspension. Still, they can react in the wash water with the positively charged water hardness ions (calcium and magnesium) , which can lead to partial deactivation. The more calcium and

magnesium molecules in the water, the more the anionic surfactant system suffers from deactivation. To prevent this, the anionic surfactants need help from other ingredients such as builders (Ca/Mg sequestrants) and more detergent should be dosed in hard water. The most commonly used anionic surfactants are alkyl sulphates, alkyl ethoxylate sulphates and soaps.

Cationic surfactants

In solution, the head is positively charged. There are 3 different categories of cationics each with their specific application:

In fabric softeners and in detergents with built-in fabric softener, cationic surfactant

s provide softness. Their main use in laundry products is in rinse added fabric softeners, such as esterquats, one of the most widely used cationic surfactants in rinse added fabric softeners.An example of cationic surfactants is the esterquat.

In laundry detergents, cationic surfactants (positive charge) improve the packing of a

nionic surfactant molecules (negative charge) at the stain/water interface. This helps to reduce the dirtl/water interfacial tension in a very efficient way, leading to a more robust dirt removal system. They are especially efficient at removing greasy stains. An example of a cationic surfactant used in this category is the mono alkyl quaternary system
Non-ionic surfactants

These surfactants do not have an electrical charge, which makes them resistant to water hardness deactivation. They are excellent grease removers that are used in laundry products, household cleaners and hand dishwashing liquids. Most laundry detergents contain both non-ionic and anionic surfactants as they complement each other's cleaning action. Non-ionic surfactants contribute to making the surfactant system less hardness sensitive. The most commonly used non-ionic surfactants are ethers of fatty alcohols

Amphoteric/zwitterionic surfactantsThese surfactants are very mild, making them particularly suited for use in personal care and household cleaning products. They can be anionic (negatively charged), cationic (positively charged) or non-ionic (no charge) in solution, depending on the acidity or pH of the water. They are compatible with all other classes of surfactants and are soluble and effective in the presence of high concentrations of electrolytes, acids and alkalis. These surfactants may contain two charged groups of different sign. Whereas the positive charge is almost always ammonium, the source of the negative charge may vary (carboxylate, sulphate, sulphonate). These

surfactants have excellent dermatological properties. They are frequently used in shampoos and other cosmetic products, and also in hand dishwashing liquids because of their high foaming properties. An example of an amphoteric/zwitterionic surfactant is alkyl betaine.

How do surfactants work in detail?
Surfactants can work in three different ways: roll-up, emulsification, and solubilization.

Roll-up mechanism

The surfactant lowers the oil/solution and fabric/solution interfacial tensions and in this way lifts the stain of the fabric.

Emulsification

The surfactant lowers the oil-solution interfacial tension and makes easy emulsification of the oily soils possible.

Solubilization

Through interaction with the micelles of a surfactant in a solvent (water), a substance spontaneously dissolves to form a stable and clear solution.

How can surfactants prevent dirt from being re-deposited?
Surfactants have a vital role to play in preventing the re-deposition of soils like greasy, oily stains and particulate dirt on the surface or fabric from which they have just been removed. This works by electrostatic interactions and steric hindrance.

Electrostatic interactions

Anionic surfactants are adsorbed on both the surface of the dirt which is dispersed in the detergent solution, and the fabric surface. This creates a negative charge on both surfaces, causing electrostatic repulsions. This repulsion prevents the soil from re-depositing on the fabric. In the presence of hardness, however, this mechanism acts like a 'bridge' between the suspended soil and the fabric. This is another reason why hardness sequestrants (a chemical that promotes Ca/Mg sequestration) are often used in detergents.

Steric hindrance:
Non-ionic surfactants like alcohol ethoxylates also adsorb on the dirt. Their long ethoxylated chains extend in the water phase and prevent the dirt droplets or particles from uniting,, and from depositing onto the fabric surface. This is shown in the illustration below: (1) Dirt is present in solution (2) The non-ionic surfactants adsorb to the dirt particles. (3) Their long hydrophilic heads extend in the water phase and as a result prevent the dirt particles/droplets from uniting and from re-depositing onto fabrics.

Petroleum(Oil) A Fossil Fuel

Author: mostafa

•9:01 AM

Oil was formed from the remains of animals and plants that lived millions of years ago i

n a marine (water) environment before the dinosaurs. Over the years, the remains were covered by layers of mud. Heat and pressure from these layers helped the remains turn into what we today call crude oil . The word "petroleum" means "rock oil" or "oil from the earth."

Products Made from a Barrel of Crude Oil (Gallons)

After crude oil is removed from the ground, it is sent to a refinery by pipeline, ship or barge. At arefinery, different parts of the crude oil are separated into useable petroleum products. Crude oil is measured in barrels (abbreviated "bbls"). A42.U.S gallon of crude oil provides slightly more than 44 gallons of petroleum products. This gain from processing the crude oil is similar to what happens to popcorn, it it gets bigger after it is popped.

One barrel of crude oil, when refined, produces about 20 gallons of finished motor gasoline, and 7 gallons of diesel , as well as other petroleum products. Most of the petroleum products are used to produce energy. For instance, many people across the United States use propaneto heat their homes and fuel their cars. Other products made from petroleum include: ink, crayons, bubble gum, dishwashing liquids, deodorant, eyeglasses, records, tires, ammonia, and heart valves.

Viscosity and Surface Tension

Author: mostafa

•10:00 PM

Viscosity
the resistance of a liquid to flow is called its viscosity
The greater the viscosity, the more slowly it flows
Measuring viscosity
How long a liquid takes to flow out of a pipette under the force of gravity
How fast an object (steel ball) sinks through the liquid under gravitational force
The Physical Basis of Viscosity
Viscosity is a measure of the ease with which molecules move past one another
It depends on the attractive force between the moleculees
It depends on whether there are structural features which may cause neighboring molecules to become "entangled"
Viscosity decreases with increasing temperature - the increasing kinetic energy overcomes the attractive forces and molecules can more easily move past each other

Surface Tension
By definition the molecules of a liquid exhibit intermolecular attraction for one another.
What happens to molecules at the surface in comparison to those in the interior of a liquid?

Molecules in the interior experience an attractive force from neighboring molecules which surround on all sides
Molecules on the surface have neighboring molecules only on one side (the side facing the interior) and thus experience an attractive force which tends to pull them into the interior
The overall result of this asymmetric force on surface molecules is that:
The surface of the liquid will rearrange until the least number of molecules are present on the surface
In other words the surface area will be minimized
A sphere has the smallest surface area to volume ratio
The surface molecules will pack somewhat closer together than the rest of the molecules in the liquid
The surface molecules will be somewhat more ordered and resistant to molecular disruptions
Thus, the surface will seem to have a "skin"
The "inward" molecular attraction forces, which must be overcome to increase the surface area, are termed the "surface tension"
Surface tension is the energy required to increase the surface area of a liquid by a unit amount
Water
Intermolecular hydrogen bonds
Surface tension at 20?C is 7.29 x 10-2 J/m2
Mercury
Intermolecular metallic (electrostatic) bonds
Surface tension at 20?C is 4.6 x 10-1 J/m2
Cohesive forces bind molecules of the same type together
Adhesive forces bind a substance to a surface
For example, attractive forces (hydrogen bonding) exists between glass materials (Silicon dioxide) and water.
This is the basis of "capillary" action, where water can move up a thin capillary, against the force of gravity. Surface tension "pulls" neighboring water molecules along.
The liquid climbs until the adhesive and cohesive forces are balance by the force of gravity

Author: mostafa

•1:32 PM

Chemical Dispersants
Dispersants are a group of chemicals designed to be sprayed onto oil slicks, to accelerate the process of natural dispersion. Spraying dispersants may be the only means of removing oil from the sea surface, particularly when mechanical recovery is not possible. Their use is intended to minimize the damage caused by floating oil, for example to birds or sensitive shorelines. However, in common with all spill response options, the use of dispersants has its limitations and should be carefully controlled. Dispersant use will be dependent upon national regulations governing the use of these products.
How chemical dispersion works?
Natural dispersion of an oil slick occurs when waves and other turbulence at the sea surface cause all or part of the slick to break up into droplets and enter into the water column. The addition of dis

persants is intended to accelerate this process.
Dispersants have two main components, a surfactant and a solvent. Surfactants are molecules which have an affinity for two distinct liquids which do not mix, acting as an interface between them. A part of the surfactant molecule used in dispersants has an attraction to oil (i.e. it is oleophilic) while another part has an attraction for water (i.e. it is hydrophilic). Common washing-up liquid is another example of a product that contains surfactants.
When a dispersant is sprayed onto an oil slick, the interfacial tension between the oil and water is reduced, promoting the formation of finely dispersed oil droplets. These droplets will be of varying sizes and although the larger ones may rise back to the surface some will remain in suspension. If dispersion is successful, a characteristic plume will spread slowly down from the water surface a few minutes after treatment. However, the effective distribution of surfactant throughout the oil is crucial to the success of the process. To achieve the required distribution, most dispersants contain a suitable solvent which allows the dispersant to penetrate into the slick and acts as a carrier for the surfactant.
Limitations
Dispersants have little effect on very viscous, floating oils, as they tend to run off the oil into the water before the solvent can penetrate. As a general rule, dispersants are capable of dispersing most liquid oils and emulsions with viscosities of less than 2000 centistokes, equivalent to a medium fuel oil at 10-20ºC. They are unsuitable for dealing with viscous emulsions (mousse) or oils which have a pour point near to or above that of the ambient temperature. Even those oils which can be dispersed initially become resistant after a period of time as the viscosity increases as a result of evaporation and emulsification. For a particular oil, the time available before dispersant stops being effective depends upon such factors as sea state and temperature but is unlikely to be longer than a day or two. Dispersants can, however, be more effective with viscous oils on shorelines because the contact time may be prolonged allowing better penetration of the dispersant into the oil.
Types of dispersant
Type 1 dispersants are based on hydrocarbon solvents with between 15 and 25% surfactant. They are sprayed neat onto the oil as pre-dilution with sea water renders them ineffective. Typical dose rates are between 1:1 and 1:3 (dispersant: oil).
Type 2 dispersants are dilutable concentrate dispersants which are alcohol or glycol (i.e. oxygenated) solvent based with a higher surfactant concentration. Dilution is normally 1:10 with sea water.
Type 3 dispersants are also concentrate dispersants with a similar formulation to type 2 products. However, they are designed to be used neat and typical dose rates are between 1:5 and 1:30 (neat dispersant: oil).
Type 1 and 2 dispersants require thorough mixing with the oil after application to produce satisfactory dispersion. With type 3 products, the natural movement of the sea is usually sufficient to achieve this. The lower application rates required with concentrates mean that types 2 and 3 have largely superseded type 1 dispersants for application at sea.
Methods of application at sea

Dispersants can be applied to open water by a variety of methods. In general workboats are more suitable for treating minor spills in harbours or confined waters. Large multi-engine planes are best equipped for handling large off-shore spills. Small, single-engine aircraft and helicopters are suitable for treating smaller spills and near shore areas. Regardless of the method used, it must be able to apply the dispersant effectively. In order to minimise losses due to wind drift, a uniform spray pattern of larger droplets, "rain drops", are required rather than a fog or a mist.

Author: mostafa

•1:29 PM

Definition:

Usually, a process by which triglycerides are reacted with sodium or potassium hydroxide to produce glycerol and a fatty acid salt, called 'soap'.
Lipids that contain fatty acid ester linkages can undergo hydrolysis. This reaction is catalyzed by a strong acid or base. Saponification is the alkaline hydrolysis of the fatty acid esters.

soap

Author: mostafa

•1:24 PM

Have you ever tried to blow a bubble with pure water? It won't work. There is a common misconception that water does not have the necessary surface tension to maintain a bubble and that soap increases it, but in fact soap decreases the pull of surface tension - typically to about a third that of plain water. The surface tension in plain water is just too strong for bubbles to last for any length of time. One other problem with pure water bubbles is evaporation: the surface quickly becomes thin, causing them to pop.

Soap molecules are composed of long chains of carbon and hydrogen atoms. At one end of the chain is a configuration of atoms which likes to be in water (hydrophilic). The other end shuns water (hydrophobic) but attaches easily to grease. In washing, the "greasy" end of the soap molecule attaches itself to the grease on your dirty plate, letting water seep in underneath. The particle of grease is pried loose and surrounded by soap molecules, to be carried off by a flood of water.

In a soap-and-water solution the hydrophobic (greasy) ends of the soap molecule do not want to be in the liquid at all. Those that find their way to the surface squeeze their way between the surface water molecules, pushing their hydrophobic ends out of the water. This separates the water molecules from each other. Since the surface tension forces become smaller as the distance between water molecules increases, the intervening soap molecules decrease the surface tension. If that over-filled cup of water mentioned earlier were lightly touched with a slightly soapy finger, the pile of water would immediately spill over the edge of the cup; the surface tension "skin" is no longer able to support the weight of the water because the soap molecules separated the water molecules, decreasing the attractive force between them.

Because the greasy end of the soap molecule sticks out from the surface of the bubble, the so

ap film is somewhat protected from evaporation (grease doesn't evaporate) which prolongs the life of the bubble substantially. A closed container saturated with water vapor (as in the Exploratorium "Soap Film" exhibit) also slows evaporation and allows soap films to last even longer. I've blown soap bubbles on a watch glass glued to the bottom of a jar with a large mouth. Once I've sealed the jar the environment will support the bubble for quite a long time. My longest lasting bubble survived for three months! Eiffel Plasterer, a dear departed friend, farmer, educator, and bubble fanatic who lived in Huntington, Indiana blew a bubble that lasted for 341 days!

National Cement Company (production line)

Author: mostafa

•2:36 PM

the images describe the following items:

(1)reclaimers
2)conveyers
3)feeding bins
4)raw mill
5)separator
6)cyclones
7)air slide
8)bucket elevator
9)conditon tower

10)water pumps
11) EP filter which serve raw mill and branch 1

(12)EP filter which serve branch 2
(13)the Ep fans
(14)the chimneys

(15)blowers

(16)raw material silos
(17)Bag filters
(18)areation fans
(19)pony ladel
(20)bucket elevetor
(21)distibuter
(22)bins
(23)air left

(24)the preheater
(25)the kiln shell
(26)By pass filter
(27)main burner

(28)grate cooler
(29)clinker transport
(30)gravel filter

(31)clinker silos
(32)feeding bins
(33)cement mill
(34)EP filter
(5)cement silos
(6)water tank

water in our life

Author: mostafa

•1:55 PM

WATER
Water is a common chemical substance that is essential to all known forms of life. In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapour.
Water cycle
The movement of water around, over, and through the Earth is called the water cycle. We can consider the starting point and ending point are the same.

Water is Essential for Life
It covers 71% of the earth's surface and makes up 65 % of our bodies. Everyone wants clean water-- to drink, for recreation, and just to enjoy looking at. If water becomes polluted, its loses its value to us economically and aesthetically, and can become a threat to our health and to the survival of the fish living in it and the wildlife that depend on it.

Problem
-80%of infectious diseases.-6 million people die each year.-3 million die from water_related diarrhea alone most of those diving are small chilern.

How does water pollution occur?

Although some kinds of water pollution can occur through natural processes, it is mostly a result of human activities.We use water daily in our homes and industries.After we have used it and contaminated it.most of it returns to these locations. The used water of a community is called wastewater, or sewage. If it is not treated before being discharged into waterways, serious pollution is the result.

Water analysis
Physical analysis

(1)Turbidity.
(2)Colour.
(3)Taste,Smell.
(4)Total suspended solids.

Chemical Analysis
Nitrogen forms:
(1)Amonia

(2)Nitrite

(3)Nitrate
Microbiological Analysis
(1)Bacteria.
(2)Algae.
(3)Protozoa

Water Treatment
Commom Water problems and treatment
(1)Bacteria
Disinfecation

(2) Fuel products
Carbon Filter

(3) Hard water
Water Softner
(4)Metals
Reverse osmosis unit or distillation
(5)Pesticides
Reverse psmosis unit or distillation
(6) PH
Neutralizing filter

(7)Taste and odors
Carbon filter
(8) Ion particles
Water softner or iron filter

(10) Hydrogen Sulfide gas
Oxidizing Filter Followed by a carbon filter or Chlorination

INTERMOLECULAR FORCES

Author: mostafa

•1:27 PM

Introduction:
The physical properties of melting point, boiling point, vapor pressure, evaporation, viscosity, surface tension, and solubility are related to the strength of attractive forces between molecules. These attractive forces are called Intermolecular Forces.

1. IONIC FORCES:
The forces holding ions together in ionic solids are electrostatic forces. Opposite charges attract each other. These are the strongest intermolecular forces. Ionic forces hold many ions in a crystal lattice structure.

2. DIPOLE FORCES:

Polar covalent molecules are sometimes described as "dipoles", meaning that the molecule has two "poles". One end (pole) of the molecule has a partial positive charge while the other end has a partial negative charge. The molecules will orientate themselves so that the opposite charges attract principle operates effectively.
In the example, hydrochloric acid is a polar molecule with the partial positive charge on the hydrogen and the partial negative charge on the chlorine. A network of partial + and - charges attract molecules to each other.

3. HYDROGEN BONDING:

The hydrogen bond is really a special case of dipole forces. A hydrogen bond is the attractive force between
the hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule. Usually the electronegative atom is oxygen, nitrogen, or fluorine.
In other words - The hydrogen on one molecule attached to O or N that is attracted to an O or N of a different molecule.
In the graphic, the hydrogen is partially positive and attracted to the partially negative charge on the oxygen or nitrogen. Because oxygen has two lone pairs, two different hydrogen bonds can be made to each oxygen.
This is a very specific bond as indicated. Some combinations which are not hydrogen bonds include: hydrogen to another hydrogen or hydrogen to a carbon.

4. INDUCED DIPOLE FORCES:

Forces between essentially non-polar molecules are the weakest of all intermolecular forces. "Temporary dipoles" are formed by the shifting of electron clouds within molecules. These temporary dipoles attract or repel the electron clouds of nearby non-polar molecules.
The temporary dipoles may exist for only a fraction of a second but a force of attraction also exist for that fraction of time. The strength of induced dipole forces depends on how easily electron clouds can be distorted. Large atoms or molecules with many electrons far removed from the nucleus are more easily distorted.

portland cement

Author: mostafa

•6:25 PM

Intermolecular Forces

Author: mostafa

•11:41 AM

Introduction

The physical properties of melting point, boiling point, vapor pressure, evaporation, viscosity, surface tension, and solubility are related to the strength of attractive forces between molecules. These attractive forces are called Intermolecular Forces. The amount of "stick togetherness" is important in the interpretation of the various properties listed above.
There are four types of intermolecular forces. Most of the intermolecular forces are identical to bonding between atoms in a single molecule. Intermolecular forces just extend the thinking to forces between molecules and follows the patterns already set by the bonding within molecules