How Cobb Test Is Done?

Approx. 100 ml of water is poured into the cylinder. After 30 Minutes, the water is poured out. The specimen is weighed while wet and the amount of water absorbed by 1 m² of specimen material is calculated.

What is a good Cobb value?

Cobb values for liner grades are typically specified as being Target 100g/m² up to a Maximum of 150g/m², which means they are moderately chemically sized, and this applies across a broad range of paper weights possibly from 100g/m²–440g/m².

How do you determine Cobb value?

Take the sample out carefully and use the roller to extract the extra amount of water. Weigh the sample. Now subtract the dry weight from the wet weight, the value you have is the Cobb value of Kraft paper. This the amount of water the sample absorbed in a defined time period.

Why Cobb test is important for packaging?

The manufacturers of the packaging materials also have to ensure the moisture absorption capacity. Cobb sizing tester measures and calculates the water or any fluid consumed by the paper, fibreboard, and paperboard in at any given point of time during varied climatic conditions.

What is the use of Cobb?

Cobb sizing tester determines the amount of water or any liquid absorbed by the paper, corrugated fibreboard, and paperboard in a given period of time under some conditions. Water absorptiveness is a function of various characteristics of paper or board such as porosity, sizing, etc.

What is the unit of Cobb?

The Cobb test determines the amount of water absorbed into the surface by a sized (non-bibulous) paper, paperboard, and corrugated fibreboard paper or paperboard sample in a set period of time, usually 60 or 180 seconds (Cobb60 or Cobb180). Water absorbency is quoted in g/m2.

Why is it called Cobb?

Cobb salad received its name from a restaurant owner named Robert Cobb. After a long night of service, Chef Cobb was tired and hungry at the Brown Derby in Hollywood, CA. He threw together a bunch of leftover ingredients into a bowl with lettuce and tossed them together with French dressing.

What is Cobb factor?

The Cobb value provides information about the water absorption capacity of cartonboard samples. The Cobb test determines the amount of water that is taken up by a defined area of cartonboard through one-sided contact with water, within a certain amount of time.

Is standard for Cobb test?

The Cobb Test is carried out according to the following standards: ISO 535, EN 20535 and TAPPI T 441.

What is the meaning of Cobb?

cobb (plural cobbs) A sea-cob or gull. A pier made from cobblestones. A hand-basket, especially made from wicker. A building material consisting of clay, sand, straw, water, and earth, similar to adobe.

What should be Cobb value paper?

Cobb value or water absorptiveness is counted by a 1 sq. meter sample of paper or corrugated sheet to measure the mass of water absorbed in a given time. This value helps to maintain the quality of the paper used in the packaging industry.

Which test is used for packaging?

Bursting strength test (BST)
The burst strength test, also known as the Mullen test, is commonly compared to the edge crush test, as they both evaluate the strength of corrugated or cardboard materials. Together these two tests are the most commonly recommended packaging lab tests for importers.

How can Cobb value be reduced in paper?

Surface sizing with mixture of oxidized starch and AKD, at the ratio of 10 to 1, is the best method for reducing Cobb value of the papers along with preserving paper strength, which is used now in the industry for producing fluting and test-liner papers.

What is the normal Cobb angle?

Result of the PACS method: The range of Cobb angles for 50 cases was 25~125°, the median was 60°, the average value was 60.96 ± 21.08°, and 95% confidence interval was 54.9°, 66.7°.

What is the Cobb method for scoliosis?

Cobb suggested that the angle of curvature be measured by drawing lines parallel to the upper border of the upper vertebral body and the lower border of the lowest vertebra of the structural curve, then erecting perpendiculars from these lines to cross each other, the angle between these perpendiculars being the ‘angle

Why is Cobb’s method preferred?

Compared to other methods of assessing spinal curvature, the Cobb angle method is preferred for its better reproducibility [7], easier application, and suitability for measuring more severe spinal curvature.

Who invented Cobb test?

In the 1950s, the Strong-Cobb tester was introduced. It was patented by Robert Albrecht on July 21, 1953. and used an air pump.

How is water absorption measured?

For the water absorption test, the specimens are dried in an oven for a specified time and temperature and then placed in a desiccator to cool. Immediately upon cooling the specimens are weighed. The material is then emerged in water at agreed upon conditions, often 23°C for 24 hours or until equilibrium.

What is water absorption of brick?

As per IS 1077: 1992, clause 7.2, Bricks after immersion in cold water for 24 hours, water absorption shall not be more than 20 percent by weight upto class 12.5 and for the classes above 12.5 water absorption shall be between 12.5 and 15 percent.

How is Cobb made?

Cob, cobb, or clom (in Wales) is a natural building material made from subsoil, water, fibrous organic material (typically straw), and sometimes lime. The contents of subsoil vary, and if it does not contain the right mixture, it can be modified with sand or clay.

Where did Cobb come from?

Cobb was probably a nickname that then evolved into a surname in England. It has Old Norse and Anglo-Saxon origins, from the word kobbi meaning “lump,” and would likely describe a large, well-built and impressive man. Cobbe was an early spelling.