NITRA developed Smoothness Tester for textile sheeting materials

(Patent application no. 2053/DEL/2015 dated 07.07.2015)

  

Fabric smoothness-roughness is considered as one of the most important factors of clothing comfort. It is also a significant factor in today’s consumer buying decision. The buyers always have complaint that the smoothness of fabric is not maintained and varies from one lot to other. Fabric smoothness behaviour is directly linked to the fabric surface friction behaviour. The fabric surface characteristics depend upon yarn characteristics; weave particulars, finishing treatment etc. Ultimately it is finishing process which alters smoothness behviour as per the requirement of buyers if other parameters are nearly same. At present, the finisher evaluate the quality of finishes used to impart smoothness to the fabric by rubbing the finished fabric mechanically against itself or feeling it by rubbing between the finger and the thumb which is purely a subjective assessment.

Hence, there is a need to develop a low cost instrument that eliminates the subjective evaluation of fabric smoothness property. Such an instrument will be of help to the finishers to precisely evaluate different kind of finishes which they use in their day-to-day operations.

To assess performance of smoothness property of fabric, NITRA has invented first-of- its-kind instrument, to accurately measure smoothness properties of fabrics. The instrument works in close chamber and facility also provided to control humidity and temperature. The instrument is available in two types of versions. In the first version, there is no provision is provided for controlling temperature and humidity inside the chamber and in the second version this facility is provided depending upon the need of users.

For further details, please contact

Prof (Dr) M.S.Parmar

Joint Director (A)

Northern India Textile Research Association

Sector-23, Raj Nagar, Ghazuabad (U.P)

Email: drmsparmar@nitratextile.org, mail@nitratextile.org

Phone: 0120-2783090/094/095/586/592/638/334, Fax: 0120 2783596

Reaction of Hydrogen per Oxide Killer

Catalase Enzyme is also known as (Highly Concentrated Hydrogen Peroxide Killer Enzyme).

Catalase is highly effective in catalyzing the decomposition of hydrogen peroxide into oxygen and water. In textiles processing, this is often the most preferred mode of hydrogen per oxide removal after bleaching and break down products are totally inert to reactive dyestuff. This enzyme accommodates broad range of pH as well as temperature and remains effective even at high concentration of hydrogen peroxide.

REMOVAL OF HYDROGEN PER OXIDE WITH CATALASE

                Catalase enzyme

2H₂O₂                                                    O₂ + 2H₂O

Bleaching (100⁰C)                Drop Bath                 Raise (30 - 70⁰C)               add acetic acid and catalase (10 to 20⁰C)                Reactive dye.

Catalase removes hydrogen per oxide in very simple way. It is cost effective and reliable. Excess reducing agent can damage the fabric and also effect dyeing. Less amount of reducing agent will not remove Hydrogen per oxide properly and will affect dyeing process again.

Relevance of Quality and Quality Related Customer Complaints - Dr M S Pa...

Relevance of Quality and Quality Related Customer Complaints - Dr M S Parmar

Language: Mix (English and Hindi). See the link below .

https://www.youtube.com/watch?v=V0s54tauQeY

Spectrophotometer

Every chemical compound absorbs, transmits, or reflects light (electromagnetic radiation) over a certain range of wavelength. Spectrophotometry is a measurement of how much a chemical substance absorbs or transmits. Spectrophotometry is widely used for quantitative analysis in various areas (e.g., chemistry, physics, biology, biochemistry, material and chemical engineering, clinical applications, industrial applications, etc). Any application that deals with chemical substances or materials can use this technique. In biochemistry, for example, it is used to determine enzyme-catalyzed reactions. In clinical applications, it is used to examine blood or tissues for clinical diagnosis. There are also several variations of the spectrophotometry such as atomic absorption spectrophotometry and atomic emission spectrophotometry.

A spectrophotometer is an instrument that measures the amount of photons (the intensity of light) absorbed after it passes through sample solution. With the spectrophotometer, the amount of a known chemical substance (concentrations) can also be determined by measuring the intensity of light detected. Depending on the range of wavelength of light source, it can be classified into two different types:

• UV-visible spectrophotometer: uses light over the ultraviolet range (185 - 400 nm) and visible range (400 - 700 nm) of electromagnetic radiation spectrum.
• IR spectrophotometer: uses light over the infrared range (700 - 15000 nm) of electromagnetic radiation spectrum.

In visible spectrophotometry, the absorption or the transmission of a certain substance can be determined by the observed color. For instance, a solution sample that absorbs light over all visible ranges (i.e., transmits none of visible wavelengths) appears black in theory. On the other hand, if all visible wavelengths are transmitted (i.e., absorbs nothing), the solution sample appears white. If a solution sample absorbs red light (~700 nm), it appears green because green is the complementary color of red. Visible spectrophotometers, in practice, use a prism to narrow down a certain range of wavelength (to filter out other wavelengths) so that the particular beam of light is passed through a solution sample. 

Devices and mechanism

Figure 1 illustrates the basic structure of spectrophotometers. It consists of a light source, a collimator, a monochromator, a wavelength selector, a cuvette for sample solution, a photoelectric detector, and a digital display or a meter. Detailed mechanism is described below.  

A spectrophotometer, in general, consists of two devices; a spectrometer and a photometer. A spectrometer is a device that produces, typically disperses and measures light. A photometer indicates the photoelectric detector that measures the intensity of light.

• Spectrometer: It produces a desired range of wavelength of light. First a collimator (lens) transmits a straight beam of light (photons) that passes through a monochromator (prism) to split it into several component wavelengths (spectrum). Then a wavelength selector (slit) transmits only the desired wavelengths, as shown in Figure 1.
• Photometer: After the desired range of wavelength of light passes through the solution of a sample in cuvette, the photometer detects the amount of photons that is absorbed and then sends a signal to a galvanometer or a digital display, as illustrated in Figure 1.

Adams Chromatic Valence Color Space

Adams chromatic valence color spaces are a class of color spaces suggested by Elliot Quincy Adams. 

Two important Adams chromatic valence spaces are CIELUV and Hunter Lab.

Chromatic value/valence spaces are notable for incorporating the opponent process model, and the empirically-determined 2½ factor in the red/green vs. blue/yellow chromaticity components (such as in CIELAB).

In 1942, Adams suggested chromatic value color spaces. Chromatic value, or chromance, refers to the intensity of the opponent process responses, and is derived from Adams' theory of color vision.

A chromatic value space consists of three components:

·         {\displaystyle V_{Y},}V_Y the Munsell-Sloan-Godlove value function: {\displaystyle V_{Y}^{2}=1.4742Y-0.004743Y^{2}}(V_Y)² = 1.4742Y – 0.004743Y²

·         {\displaystyle V_{X}-V_{Y}}V_x – V_y,  the red-green chromaticity dimension, where {\displaystyle V_{X}}V_x is the value function applied to {\displaystyle (y_{n}/x_{n})X}(y_n/x_n)X  instead of Y

·         {\displaystyle V_{Z}-V_{Y}}V_Z - V_Y, the blue-yellow chromaticity dimension, where {\displaystyle V_{Z}}V_Z is the value function applied to {\displaystyle (y_{n}/z_{n})Z}(y_n/z_n)Z  instead of Y

A chromatic value diagram is a plot of {\displaystyle V_{X}-V_{Y}}V_X - V_Y (horizontal axis) against {\displaystyle 0.4(V_{Z}-V_{Y})}0.4(V_Z – V_Y) (vertical axis). The 2½ scale factor is intended to make radial distance from the white point correlate with the Munsell chroma along any one hue radius (i.e., to make the diagram perceptually uniform). For achromatic surfaces, {\displaystyle (y_{n}/x_{n})X=Y=(y_{n}/z_{n})Z}(y_n/x_n)X = Y = (y_n/z_n)Z  and hence {\displaystyle V_{X}-V_{Y}=0}, {\displaystyle V_{Z}-V_{Y}=0}V_X – V_Y = 0, V_Z – V_Y = 0. In other words, the white point is at the origin.

Constant differences along the chroma dimension did not appear different by a corresponding amount, so Adams proposed a new class of spaces, which he termed chromaticvalence. These spaces have "nearly equal radial distances for equal changes in Munsell chroma".

Kubelka-Munk equations:

When light is fall on some sample, some part of the light reflected, some are absorbed and some are scattered. If the sample is having opacity more than 70% then as per Kubelka Munk (established in 1931) following is the relation between reflectance, scattering and absorption of light:

K/S= (1 – 0.01R)²/2(0.01R)

The mathematical basis for all color matching software is the Kubelka-Munk series of equations. These equations state that for opaque samples such as textile materials, the ratio of total light absorbed and scattered by a mixture of dyes is equal to the sum of the ratios of light absorbed and scattered by the dyes measured separately. Where absorption is defined as "K" and scattering is defined as "S", Kubelka-Munk states that _:

(K/S) mixture = (K/S) dye 1 + (K/S) dye 2 + (K/S) dye 3 + ...

K/S is not a readily measurable quantity, but it can be calculated from the reflectance of a sample -- "R" -- by the Kubelka-Munk equation that states

 K/S= (1-R)²/2R

K/S  value is proportional to dye  concentration in the substrate

K/S=kC

Where k is constant and C is concentration of dyes or colorant