Error Analysis Of Hand Length Measurement Of Goat'S Velvet

< p > < < a href= "//www.sjfzxm.com/news/index_c.asp > > goat velvet > /a > test, the average diameter and length of hand pull are two indicators, and the quality characteristics are reference indexes. Therefore, the length of hand pull is an important index to evaluate the grading of goat's velvet.

In the hand pull test of the same group of goat's Velvet samples, there are often different degrees of difference, causing the error of the length of the hand pull in the goat's Velvet test.

The length of hand pull is a major assessment index, which is related to the evaluation of goat's Velvet grades. Therefore, it is very important to analyze the causes of differences and prevent differences.

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< p > < strong > 1 the main reason for the length difference of hand pull is < /strong > < /p >.

< p > in the experiment of hand length of goat's velvet, the test environment, operation method, sample consistency, sampling quantity and measuring position will affect the length result.

The author focuses on the effect of sample moisture regain and manipulation methods on the length of the goat's original hand length.

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< p > 1.1, moisture regain, the influence of the length of the opponent's pull < /p >

< p > the moisture regain of goat's Velvet samples is directly related to the length of the length of the hand pull. The main reason is that when the moisture content is less than that of the dry fiber, the tensile strength of the fiber is enhanced, and the fibers are not easy to straighten, and it is easy to shrink and break. When the wool fibers absorb more moisture, the fibers expand and the fibers are not only straight and elongated.

At the same time, due to the role of water molecules, the interaction force between fibers is reduced, the tensile strength is weakened, fibers are easy to straighten and are not easy to retract.

According to the accumulation in the work practice, when the moisture regain is below 13%, the length of the original hand will be shorter; the moisture regain will be stable between 13% and 17%; when the moisture regain increases to more than 17%, the length of the hand pull will be longer.

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< p > 1.2 operation method the influence of the length of the opponent's pull < /p >

< p > > a href= "//www.sjfzxm.com/news/index_q.asp" > gb18267 "Cashmere" standard < /a > stipulates: take the length of the sample, pull the sample on the work table, pull out the length of the hand sample randomly, use the hand to gently finish, remove the coarse, longer goat hair and some impurities.

Two hands are used to divide the sample evenly, then the two ends of the sample are combined with each other and tightly held in one hand, and the other hand is used to pick and finish the fibers. During the extraction process, the coarse wool is removed, and it is repeatedly adjusted to make it a neat velvet at one end, the fiber is naturally straight, the weight is about 50mg, and the width is about 20mm.

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< p > because each operator has different methods of understanding and operating standards, it will also cause differences in the length of hand pull.

For example, the size of the hand pull, the number of samples, the difference between the length of throwing and the quality of the bundles are all factors affecting the length of the hand pull.

In addition, goat origin < /p >

The difference between the number of velvet, the number of prick and the shape of the original velvet is also one of the factors that affect the length of the P.

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< p > < strong > 2, how to prevent the error of hand length test < /strong > < /p >

< p > 2.1, choose the suitable test environment < /p >

< p > first, we should avoid the experiment of hand length of goat's velvet in high temperature, dry and climate changing environment.

If the conditions permit, it can be used in the standard atmosphere of two levels, namely, temperature (20 + 2), relative humidity in (60 + 3)% environment, and the sample is pre humidified for at least 4 hours.

If conditions are not allowed, the length of hand pull should be tested in a well ventilated and certain temperature and humidity testing environment.

Practice has proved that when the moisture regain of the sample exceeds 17%, the fibers are straight and the shrinkage rate becomes weaker, the fibers are easy to straighten out, and the length of the handle is longer than that of the moisture regain of 13% and below.

Therefore, according to the temperature and humidity of the test environment, the moisture regain of the sample is controlled between 13% and 17%.

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< p > 2.2. Pay attention to the operative technique < /p >.

< p > too much or too little sampling will cause the deviation of the length of hand pull.

In general, the number of samples is directly proportional to the length. When the sample is too much, the results are easy to draw. When the sample is too small, the results are easy to shorten.

In the process of experiment, we should randomly extract the typical velvet samples, eliminate the long and short throw, and take the long and long wool as far as possible.

During sampling, we should pay attention to the shape of velvet, such as velvet, leather, dry back, ash, wool, scabies, moth and mouldy.

The defect resistance is weak, and the fiber is easy to straighten and stretch easily during the process of hand pulling. Therefore, the force should be properly handled during the process of hand pulling sample. If the force is too long, the fiber will be broken too much, resulting in short hand pull results.

It is learned from practice that the hands are divided into two parts, and the two ends of the sample are separated into one hand, tightly held in one hand, and one sample is taken about 10 times with the other hand. After removing the coarser and longer goat hair, after the repeated finishing, the pile bundles are about 80mg, the width is about 20mm, enough to cover the velvet plates, and the length between the two ends is not the length of the pile.

Therefore, the samples of cashmere fiber must be representative. After sampling, the most scientific method is to accurately and quickly arrange the velvet bundles, which is the basic requirement to avoid the difference of hand length.

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< p > < strong > 3 summarizes < /strong > < /p >.

< p > above all, the accuracy of the length of the hand pull length of goat's raw wool is affected by subjective and objective factors. Therefore, in the hand pull length test, the sampling should be representative, standardized and standardized, and the size of the velvet bundle should be normalized, and the cutting volume is less than a href= "//www.sjfzxm.com/news /index_s.asp".

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