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Cоllоidаl Dispersion or Effective Road Surface Pavement? What is Bitumen Emulsiоn for Road Construction?

Road construction industry

Bitumen emulsion for road construction is a colloidal dispersion consisting of two components, bitumen and water that do not blend.

The emulsion for road construction is made by the dispersion of bitumen in water solvent of emulsifier.

The performance characteristics of the latter influences the process of bitumen emulsion production.  One way (direct) is that bitumen is dispersed in water.  The other one (reverse) is that drops of water are distributed in the bitumen.

In the road construction industry, bitumen emulsion is more desirable because of its relatively low viscosity.  The name of this emulsion, bitumen emulsion for road construction, gives us a rough idea of the fact that this emulsion is used for paving or treating road surfaces such as repairing potholes and providing a tack coat for the road base.

There are many production methods as well as applications for bitumen emulsions.  The emulsion for road construction usually will consist of 50-70% bitumen, 30-50% water and 0.6 to 1.6% emulsifier.  The exact mix will depend on the application and the recipe.

Emulsification of bitumen can be realized by using special equipment.  In producing bitumen, the components are mixed by means of a colloid mill or ultrasound hydrodynamic cavitation.

The usage of an ultrasound system for blending is unique ans special.  The system is based on ultrasound hydrodynamic cavitation.  This system is used to make solution homogeneous by means of pressure fall and the separation of bitumen particles.

Additionally, this equipment also operates according to a colloid mill principle with a minor load.  The advantages of such a blending of emulsions are as follows: (1) exact metering control of the components; (2) blending cycle time reduction; and (3) non-use of blending containers that ensure a homogeneous final product.

Such performance characteristics such as safety, environmental friendliness and service life extension should be mentioned while speaking about the advantages and quality of the bitumen emulsion itself.

It is therefore, bitumen emulsion for road construction that enjoys a wide popularity in many branches of the economy.  The performance characteristics listed above  can be supplemented with the following: (1) no need to warm up the mixture before using; (2) possibility to work with this emulsion at a low temperature (up to +5°C/41º); (3) fire prevention; (4) energy and labor cost reduction; (5) compatibility with multiple kinds of solid materials; (6) better adhesion to mineral materials owing to the emulsifier; and (7) less discharge of pollutants into the air.

Modified Bitumen: The Scheme of Production

Solutions

There has been an increased amount of  heavy load carrying vehicles using our main roadway systems.  The heavy, and often overweight vehicles is one of the the main reasons for the deformation of the bitumen/asphalt based road systems.

The properties of bitumen are modified by the addition of special polymer additives.  A “Modified Bitumen” product is the result of this process.  The special additives increase the heat and cold resistance as well as the resilience of the adhesive material necessary for the modified bitumen to properly adhere to the road surface.  Additionally, these special additives will increase the resilience of the road surface when under great stress and thereby prolong the service life of the roadway.  It is therefore, the use of “Modified Bitumen” that will greatly improve and prolong the ability of the road surface to resist the stresses and abuses from overweight vehicle traffic.

The chemical additives known as “atactic polypropylene,” isotactic polypropylene,” and s”tyrene-butadiene-styrene” are mostly used as modifiers for the bitumen products.  Such mixtures as rubber modified bitumen or plasticated bitumen (raw material, made on the basis of rubber and bitumen) as well as atactic polypropylene modifier are much less common for use in the production of modified bitumen.  Each type of additive however,  has a wide range of properties that can be both beneficial, as well as harmful to modified bitumen products.

An example of a beneficial additive is an increased resistance to the effects Ultra Violet Radiation (UV) and chemical resistance to alkali and acid solutions made possible with the inclusion of atactic polypropylene additives. Additionally, they make the road surface more resistant to high temperature extremes and more adhesive to metal and glass surfaces and particles.
All the materials for manufacturing modified bitumen provide a “ready mixture” for use with such performance characteristics as cold resistance and elasticity.  These characteristics help the mixture to take a set form.

In many parts of the world, modified bitumen production is performed at oil refineries or at special concentration plants under constant laboratory quality controls.  The equipment for modified bitumen production is available around the world and is capable of producing a wide range of products to meet a wide range of applications.

The manufacturing of modified bitumen equipment is customized not only in China, Europe or America, but also in the Common Wealth of Independent States (CIS).  All these countries have built up a great demand for bitumen production equipment.
There are two traditional ways to manufacture modified bitumen.  They are both based on the use of modern blending equipment.

One way is that modified bitumen is manufactured by making bitumen-polymer dispersion in colloid mills with a large shear force.  The other method consists of adding polymer to bitumen.  The latter process is done with the help of colloid mills that rotate slowly with only minor shear force.

The changes made to the polymer molecular structure is the main disadvantage of using the colloid mills.  The problem is that at the the end of the blending process, the average molecular weight of the polymer will have been reduced.

Modified bitumen equipment usually will consist of the following items: (1) bitumen heater (where original bitumen is warmed up); (2) a gear-type pump; (3) a container for blending; and (4) blending equipment (namely colloid mills of different kinds).  After blending, the original material and modifiers make up a homogeneous mixture called modified bitumen.

In the first stage of processing, the modified bitumen is fed to a heater with the help of a gear-type pump. In the latter stages, another pump supplies this mixture directly to the asphalt-concrete  paver, or it can be packaged for long or short term storage in the form of  briquettes.  At all stages of modified bitumen production the heating is performed by using the electrical tape heaters.
The modern process of modified bitumen production is automated.  Temperature control and monitoring as well as weighing and metering of plasticizer and modifier are all carried out automatically.

The quality of modified bitumen is first checked by a well trained eye and then samples are taken for laboratory analysis to fully ensure quality and compliane with laws and regulations.

The Design and Functions of the “Colloid Mill”

Colloid Mill

Colloid mills are a very unique kind of industrial equipment.  They are used for the grinding of road construction materials and perform the grinding through the effect of cavitating forces.  These forces result from considerable centrifugal loads.

GlobeCore produces and supplies the domestic and international road construction industry with a wide range of equipment for the production of bitumen emulsions and modified bitumen products.  The GlobeCore brand of equipment may vary from simple colloid mills to complex systems for blending operations.  The grinding process in the colloid mills is performed by friction or blows.  This process is performed either dry or wet.

The colloid mills, that use a wet grinding process, consist of a body with a tapered seat in the middle of the mill.  Inside the seat there is a rotor fixed on a vertical shaft that rotates with a speed of between 1,800 and 7,500 revolutions per minute (RPM).

The liquid runs through a special opening and flows between the tapered seat and the rotor.  The solid particles wear down and go out together with the liquid through an outlet hatch.  A micrometer screw regulates the gap between the seat and the rotor.  The micrometer screw helps to regulate the size of the gap needed for grinding the polymer so there is sufficient homogenization of the final product.  Grinding of the solid particles in the colloid mills is performed due to shear pressures created by the liquid films.  These films of liquid are formed on the moving and unmoved smooth surfaces of the rotor and the seat.

Additional functions of the colloid mills may include modern optional features that supplement the standard features of the plant.  For example, they might include a semi-automated operating system of the bitumen content  in the emulsion, a system of heating and preparation of soap solutions, and different levels of process automation with input lines for additional components.

Moreover, the GlobeCore colloid mills guarantee a high quality level of grinding and homogenization of the final product at attractive prices.  Additionally, GlobeCore provides you with qualified technical assistance at all levels of  the sales and service processes.

Technology That Will Conquer the World! Colloid Mill from GlobeCore

Colloid Mill

A colloid mill is one of the most important parts of the equipment used in the blending of bitumen emulsion products.  It grinds bitumen down to particles of between 1 and 3 microns while blending it with an emulsifier solution.

A unit for emulsion production consists of many separate units and sub-assembly parts that have their own peculiarities and provide for the overall operation of the colloid mill.  The quality of the colloid mill operation influences the characteristics of the final product output.  Bitumen emulsion, produced with the help of a special machine, is fitted with a high-production, modern colloid mill.  The mill must have good stability controls such as the ability to monitor the speed of its decay process and it should provide long service life to its owners.

A colloid mill is used for grinding the components of highly stable, ultrafine, colloidal solution suspensions, emulsions, orimulsions, pastes, bitumen modified by polymers and other ingredients.

The common principle of colloid mill operation is its use of two disks that interface with special claws.  One of them is fixed while the other one rotates.  The liquid, or semi-liquid materials are blended and become homogeneous and finely-divided by the action of centrifugal force between the two disks.

A colloid mill, used on modern bitumen emulsion equipment, consists of a steel split body with a closable plate and an inlet suction pipe.  A rotor component leans against a thrust ball bearing.  The outlet end of a drive shaft becomes thick with the help of a stuffing-box.  The colloid mill also includes a pipe that accepts the primary components.  There is a  pipe that allows the emulsion to go out.  There is also a connecting branch for an inlet and outlet that allows for a heat-transfer agent to warm up the operating head.

There are also heated colloid mills that use a heating element powered by mineral and synthetic oils to make high viscosity emulsions.

GlobeCore produces equipment for manufacturing bitumen emulsion products and modified bitumen products that are based on the performance capabilities of a modern colloid mill.  GlobeCore takes a leading position in the “high tech” equipment  markets of more than 70 countries.  The GlobeCore brand of equipment uses a high tech colloid mill in its bitmen  procesing units.

GlobeCore has been meeting the market demands over the last few years created by the world wide highway building boom and the increasing needs to coat modern building sites with emulsion products.

The GlobeCore brand of colloid mills produce high quality grinding resulting from better technolgy and the use of high quality construction materials and techniques developed by GlobeCore.

The market leading positions of GlobeCore have been achieved by years of experience and by the use of only the very highest quality materials and new production technologies used during the manufacturing process.

Furthermore, the current GlobeCore brand of colloid mills have been updated and are the newest and improved versions of previouly sucessful equipment.  They can produce unique formulations of bitumen emulsions blends and can modify bitumen products.

The products produced by the GlobeCore line of equipment become homogeneous after they pass through the colloid mill for the first time.  That is why we can say that the advantages of using GlobeCore branded equipment includes continuous production; reduction of electricity usage, reduced heat and reduced production time.  These benfits save you money and increase the value of the finished product.

A Practical Guide for Construction Companies: How to Choose the Correct Container for Bitumen?

Construction industry

Nowadays, the storage and discharge of bitumen can be difficult and expensive operations for your company.  The physical and chemical peculiarities of the material, difficult climatic service conditions, high energy consumption and a need for a long warm up times are some reasons for finding new ways of improving the process and equipment designs.

The high quality equipment offered by GlobeCore for carrying out different operations with bitumen, without damaging its quality, is a solution to the problms listed above.

The easiest way to save and exploit the characteristics of cohesive materials is through the use of modern bitumen storage tanks during the transportation stage of your operation(s). The right choice of bitumen equipment will result in a higher-quality road surface.

That is why the bitumen storage tanks should be constructed in accordance with international standards.  The form and construction of the tanks and equipment will vary depending on the customer’s needs.

For example, bitumen storage tanks are used for holding bitumen.  They are a flexible, portable system, that allows for either temporary, or permanent storage of bitumen products.

The use of storage pits for bitumen have become obsolete and outdated.  They are no longer suitable for use in the storage if bitumen products.  The cost of restoring the bitumen performance characteristics after using such storage methods, can exceed the original cost of the product.  It is therefore, no longer practical to use storage pits for your bitumen products.

The modern producers of bitumen equipment offer new models for bitumen storage and transportation that include both horizontal and vertical tank designs.

Each type has its own advantages and disadvantages as well as peculiarities of how they are used with different and specific types of products.

Horizontal bitumen storage tanks should be used if there is a large enough area for the placement of the bitumen storage tanks.  The storage and the warming up of bitumen can be performed by a coiled heater unit in a special container.  It is easier to comply with the strict requirements and provide monitoring of the product condition in the horizontal bitumen tanks.

The peculiarities of the customer’s business operations, and his own preferences or requirements, can also influence the main characteristics of a bitumen storage tank system.  Normally, horizontal bitumen storage tanks of different size capacity size are made from rolled sheetmetal that is 6 mm thick and sheathed with insulation to retain heat.  There are additional optional components that enhance the storsge units and should be a part of your modern bitumen equipment choices.  Based on the customer’s request, horizontal bitumen storage tanks can be fitted with the following:

  • thermoregisters for warming up of bitumen;
  • electric heating element;
  • temperature monitoring system;
  • Reporting system, responsible for bitumen paste indexes and the extent of fullness of the container;
  • arrangements and tools for operating of a tank and so on.

The vertical type bitumen storage tanks are mostly designed with a circulation system when using modified bitumen.  The vertical tanks can be more economic, occupy less manufacturing area and can be easier to use.  Many companies producing bitumen emulsions often prefer vertical storage tanks.

In the vertical type bitumen storage tanks, the heating system can be powered by  steam, gas, oil, or low temperature electric heaters.  The hot oil running through coiled pipes into the container heats bitumen product.  This process provides an optimal temperature level and control without overheating.

Development of bitumen storage tanks is based on a wide range of principles including:

  • energy efficiency;
  • conservation of the bitumen qualities;
  • reduction of the amount of water in the bitumen storage tank to the absolute minimum while preparing to manufacture asphalt;
  • reduced time for preparation and warming up of bitumen in the storage tank;
  • fire prevention/security;
  • compliance with environmental standards;
  • individual approach to every order.

The Quality Choice: GlobeCore Brand of Bitumen Equipment

Solutions

The  variety of bitumen equipment includes different kinds of units used for the production, storage, transporting and exploitation of bitumen and bitumen emulsion.

GlobeCore is in the business of developing and delivering bitumen equipment to the road construction industry.  GlobeCore designes and builds equipment for producing bitumen emulsion and modified bitumen.  Additionally, GlobeCore has equipment for blending, equipment for bitumen foaming, colloid mills, bitumen filters, pumping plants, modified bitumen storage tanks and many other products too numerous to list.

GlobeCore’s bitumen emulsion plants are in great demand because these plants are some of the most popular types of equipment in the modern road construction industry today.

The GlobeCore bitumen emulsion plant consists of a colloid mill as well as  high-accuracy batchers, shutoff and control valves, electronic management cards and many other useful and dynamic features.

The equipment is arranged in a standard container and does not need a special cover plate.  To start using this plant, one only needs to fill the exterior containers with bitumen, water, chemicals and emulsion.  Additionally, the whole unit, and in particular the separate parts and assemblies that come into contact with water, are made of corrosion-resistant materials and coatings.

The GlobeCore brand of modern bitumen equipment is completely automated.  These machines are fitted with powerful pumping units as well as with special quantity and quality transducers.  GlobeCore equipment works in accordance with the principle of blending and emulsification of bitumen and water stages.  The quality of the final product is the best characteristic of the ready-made, ready-to-use mixture.

GlobeCore equipment is specially designed for the production and manufacturing of bitumen emulsion.  This line of equipment is capable of blending normal and modified bitumen.  This equipment can work with and compound the elements to maintain any manufacturing process in the road construction industry.

The use of GlobeCore equipment, including bitumen production equipment, is widely used in bitumen production due to GlobeCore’s excellent operational characteristics and the high quality of the final products.

Innovations in Road Construction: What is the Benefit of Using Bitumen Emulsion?

Road construction industry, ,

In the road construction industry, bitumen emulsion is used more often than bitumen.  This cohesive material was invented in the USA and it has been used for over half a century all over the world as one of the chief components of  modern road construction materials.

Bitumen emulsion serves as the cohesive material for the tack coat.  The physical characteristics of bitumen emulsion are as follows:

  • dark;
  • sticky;
  • smelly; and
  • hard when dry.

Substance Matter; this part does not need to be heated before being used, and it is capable of being distributed on the whole aggregate surface in a layer that is smoother than the bitumen itself.  The cost of bitumen emulsion depends directly on the raw materials used in making the emulsion.  In the road construction industry, bitumen emulsion is also used for asphalt coating under conditions of high humidity and low temperature.  Moreover, it is also used for repairing potholes based on modern filling techniques such as cold working (when road repair operations are being performed), road surface treatment, and so on.

Bitumen emulsion is convenient in the servicing of road surfaces with multiple layers of paving materials.   During the processing, this cohesive material is used for texture and structural renovation of the multiple layers, prevention of premature road failure, and for protection and resistence against water.  Additionally, it provides better tire traction and reduces long term surface wear. Overall, using modern bitumen emulsion gives the road surface excellent performance characteristics and increases the service life of the roadway.

Bitumen emulsion consists of bitumen and water in the ratio of 50% bitumen and 40% water. Other products, such as cotton seed, sodium hydroxide and potassim make up the reaming 10% of the finished emulsion product.

There are two steps in the manufacturing of bitumen emulsion; (1) the bitumen stage; and (2) the water stage.

The bitumen stage can be described as the blending of bitumen with different additives known as firestarters.  The water stage is the adding of emulsifiers to the water that is prepared for making the emulsion.  The water stage includes the production of the emulsifier from the part of a pomade mixture.  The pomade  mixture consists of the after-product of cotton seed and flotogudron.  In this part of the process, these two components are blended in the water with a warm solution of sodium hydroxide or potassium hydroxide until the entire mixture becomes disolved.

At this stage of the process, these two components are placed inside the special plant for blending.   The unit is equipped with a colloid mill with rotating velocity of 6,000 turns per minute (6000 RPM).  As a result, the bitumen is reduced to tiny micro particles measured in microns.  These tiny particles form bubbles of emulsion water and are placed in a state of suspension within the liquid.  The final product of this blending process is called “Bitumen Emulsion.”

The main advantage of this emulsion is in the reduction of the amount of resources and power required to create the final product.  The operating costs are reduced, owing to the increased service life of bitumen emulsion under all extreme weather conditions from Spring through late Autumn.  Moreover, the technology of using bitumen emulsion in road construction is very eco-friendly.  There is no discharge from solvents into the air, and the explosion hazard, during processing and transporting of bitumen solvent, has been eliminated.

Bitumen emulsion increases the resilience, durability, and adhesive characteristics of the road surface coat.  It also decreases the road surface’s sensitivity to fluctuations in temperature.  Bitumen emulsion therefore, is one of the highest quality products of the modern chemical industry.

Bitumen Emulsion: Buy the Necessary Technology to Produce it or Invent Your Own?

Solutions

Bitumen emulsion is mainly used for road construction projects.  It is a direct emulsion where the dispersed phase is formed from pure or cutback bitumen.  These materials are prepared in special devices such as the GlobeCore UVB-1 unit.  This model consists of component storage containers, dispensers, colloid mill, and a container for the finished product.

The quality of the output product depends on several factors that include, the size and amount of bitumen droplets, the type and amount of emulsifier, and the acid or alkali (used for anionic emulsions).  The above factors determine the physicochemical properties of bitumen emulsion, that primarily include the acid number, conductivity, strength of the electrostatic repulsion, the sign of charge decay rate, viscosity, and coalescence.

Today there is no universal recipe for bitumen emulsion.  So the ingredients depend entirely on the purpose of the specific application.  There are however, some general rules that need to be followed and include the following:

  1. The basicity of the acids should be sufficient to ensure that a given amount of emulsifier will generate a protective layer.  Simultaneously, there should be just enough of the emulsifier in order to form one layer instead of two;
  2. The concentration of the bitumen is chosen so that it does not exceed a predetermined threshold beyond which there is loss of processing properties of the emulsion.  In practice, this threshold value is within 56% of the anionic emulsions and 70% for the cationic emulsions; and
  3. To reduce foaming, it is important to calculate an optimal temperature necessary to conduct the aqueous phase so that the temperature of the bitumen emulsion at the outlet of the colloid mill does not exceed 95°C/206°F.

One of the advantages of bitumen emulsion, owing to its main technological properties, is its stability.  The following factors with regards ti stability should be considered:

  • Stability while stored;
  • Stability with respect to mineral materials.

It is possible to artificially slowdown the decay of bitumen emulsion by adding a larger amount of emulsifier into the mixture.  Additionally, it is possible to achieve optimum pH levels by considering the nature of the binder and emulsifier.

If the acidity of the bitumen is adjusted by the addition of strong organic acids, it can form an unstable emulsion.  This is due to the migration of a significant portion of the acid introduced into the aqueous solution.  Operational reliability and quality of the bitumen emulsion is largely determined by the type of emulsifier used in the manufacturing process.

Another important property of bitumen emulsions is the rate of surface decay of the mineral material.  It determines whether it is possible to apply the emulsion in particular cases.  If cationic emulsion comes in contact with the filler, the decay is almost immediate.   It is a result of the reaction between bitumen and the surface of the stone material.  This is followed by an immediate displacement of water.

To get the desired bitumen emulsion, it is necessary to select the original bitumen with the correct physicochemical properties.  This rule applies to equipment, method, material treated, and weather conditions.  The preparation of pure bitumen therefore, can be modified or fluxed.

If you want to improve the wettability of the surface of gravel, then it is best to treat the material with a plasticized thinner.  Too much plasticizer however, can lead to a loss of cohesive properties of the binder, separation, and release of the rubble.

The adhesive and cohesive properties of the asphalt binder could be compromised if there is not enough liquid to cover the bitumen film rubble and of sufficient strength to resist dynamic stresses resulting from vehicle traffic.

Bitumen emulsions in road construction

Road construction industry

The rapid technological and scientific development changes the traditional compositions of bitumen emulsion. In combination with progressive technology, these allow to produce a wide spectrum of emulsified materials with improved performance in comparison with traditional asphalt technology.

Research of the trends in bitumen material development shows some of the most promising directions, such as:

– production of multiple emulsions with structure similar to inverse emulsions. The production is possible by preparing reverse emulsions or highly concentrated bitumen emulsions.

Amounf the many advantages of bitumen emulsion is the higher viscosity and mobility compared to regular emulsions. The disadvantage is the lack of flow during application.

Such emulsions are also quite economical even with low dispersed phase content.

Most innovations into multicomponent emulsions are related to selection of the corresponding components: polymer surfactants for better stability and surface contact etc. A method for formulating the composition of multicomponent emulsions with consideration of material for application and stability in extreme operating conditions has also been developed. The result is a material that adapts to the existing road top.

– production of monodispersed emulsions. In the general case, the composition of road construction emulsions is polydispersed, but that does not mean that such emulsions are of no interest. Application of such emulsions makes a material with better optical properties, as well as colored materials with minimum amounts of dye.

Dispersion consist of water bitumen emulsion defines its viscosity and settling rate. The latter is defined by size distribution emulsion droplets. In theory, production of an emulsion with the required drop size would allow control of the above parameters.

– production of “dry” emulsion. This product can be made from regular emulsion by mixing a special polymer into the water phase. This polymer causes formation of capsules with water droplets. The advantage of “dry” emulsions is the ability to mix several components, which do not usually mix. The ability allows to combine several various construction materials in the emulsion.

Development of bitumen emulsion production

Road construction industry

A new age in road construction began on 9 May 1922. Hugh Alan McKey registered the first bitumen emulsion patent. Within several years the application of this new material significantly changed road construction.

The amount of bitumen emulsions made in France in 1923 was several hundred tons. In 1924 it increased to 2500, and to 6000 tons in 1925. Other countries followed. By the end of 1926 the total amount of emulsion made in Germany, Britain, India, Australia and Denmark reached 150000 tons.

France increased production as well (2000000 in 1935 and 300000 tons before the start of WWII).

After the war the amount of emulsion production kept increasing.

Cationic emulsions first appeared in 1951. Their performance pushed anionic emulsion from the market. If in 1962 the ratio was 50/50, in 1971 cationic emulsions accounted fro 92% of the market. At the time the portion of bitumen in the emulsions was 60-69%.

The United States used 100000 tons of emulsion for road construction in 1953, West Germany used 140 000 tons. The amount of material used in other countries was slightly less.

Mineral materials used in road construction are silicate materials. On contact with water these materials become negatively charged, hence the higher adhesion with cationic emulsions.

The British standard BS 812:1960 regulates sampling and testing of filling material used in road construction in the UK.

It should be noted that anionic bitumen emulsion could react well with positively charged materials, but such materials are not often seen naturally.

One of the possible explanations of the advantages of the cationic emulsion is the high kinetic energy of cationic emulsifiers, allowing better adhesion to almost all solid materials.

Bitumen particles pass through a water layer around the filling material and then contact directly the solid surface. Even if the surface is positively charged, the adhesion is good due to the Van der Vaals forces.

There is another theory explaining the interaction of cationic emulsions with alkaline materials. It states that cationic emulsions always contain some free acids. They have low pH and can interact with alkali on the surface of the filling material. The results of the reaction are carbonate ions with negative charge. They neutralize ions of the cationic emulsifier. An insoluble product forms on the boundary between bitumen and mineral, strong enough for adhesion between the components.

Development of special equipment for production of bitumen emulsions (UVB-1) and polymer modified bitumen (UVB-2) by GlobeCore allows the use of these materials not only in road construction, but also in civil engineering.