Saturday 20 April 2024

Handloom Weaving: Taking a Toll on the Joints !!!



In the ancient city of Varanasi, where tradition weaves its way through the fabric of daily life, handloom weaving stands as a testament to centuries-old craftsmanship. Yet, amid the intricate patterns and vibrant colors, a silent struggle unfolds—one that echoes through the aches and pains of the artisans themselves.

Picture this: hours spent hunched over, shoulders tense, back curved, as skilled hands move rhythmically across the loom. It's a scene of dedication and artistry, but also one fraught with risk. Poor posture, exacerbated by the demands of their craft, takes its toll on the bodies of handloom weavers, leading to a myriad of musculoskeletal problems.

A recent study done by Sunita Dixit, which is published titled “Anthropometric Measurement & Assessment of Occupational Ergonomic Risks of Handloom Weaving in Varanasi District” delves into this issue, shedding light on the physical challenges faced by these artisans. Through careful evaluation of anthropometric measurements and body mass index, researchers aimed to assess the physical fitness of handloom weavers. What they uncovered was illuminating—a high prevalence of musculoskeletal disorders, stemming from the prolonged hours of static work and awkward postures inherent in traditional handloom designs.

As reported by her “In traditional old looms, normally there is no workstation adjustability and adjustment of weaving height is difficult that causes the awkward postures of the upper body. Inappropriately designed hand tools and the kind of the task are the chief causes of awkward postures of wrists and fingers. “
As can be seen from the results a full 86% of the weavers surveyed have to work with the  postures which are in the top risk category. 

The findings underscore a pressing need for intervention. By understanding the ergonomic demands of handloom weaving and the strain it places on the body, we can pave the way for meaningful change. From redesigning traditional looms to accommodate healthier working postures to implementing targeted interventions aimed at mitigating musculoskeletal risks, there are actionable steps we can take to support the well-being of handloom weavers.

One crucial tool in this endeavor is the Rapid Entire Body Assessment (REBA), which offers a systematic approach to evaluating working postures and identifying areas for improvement. Through observations of handloom weavers in action, researchers assigned scores to various body parts, pinpointing areas of concern and highlighting opportunities for intervention.

At the heart of this research lies a simple yet profound question: Are handloom weavers suffering because of unnatural postures? The answer, it seems, is a resounding yes. But with awareness comes opportunity—the opportunity to advocate for change in the ergonomic design of the machines and other adjustment , to champion the well-being of artisans whose craft is not only a livelihood but a cultural heritage.

Tuesday 9 April 2024

Is Tussar Silk Inferior to Mulberry Silk ?



In a paper entitled  "Study of property and structural variants of mulberry and Tussar silk filaments" by professor Mohan Gulrajani, one can get several hints which may lead to the answer to the question.


"A glance at the typical tensile behaviour reveals that the stress-strain curve of these two varieties is distinctly different, in that tasar shows a clear yield point and very high elongation compared to the mulberry filament."


Conclusion 1:  Tussar silk can undergo significant stretching before permanently deforming.

The tusar silk stress-strain curve exhibits a clear yield point. A yield point is a point on the stress-strain curve where the material transitions from elastic deformation (where it returns to its original shape after the force is removed) to plastic deformation (where it retains some deformation even after the force is removed). This suggests that Tussar silk can undergo significant stretching before permanently deforming. 

Conclusion 2:  Tussar can stretch a lot before reaching its breaking point compared to mulberry silk.

The stress-strain curve of tussar silk also shows very high elongation compared to mulberry silk. Elongation refers to how much a material stretches before breaking. The fact that tussar silk exhibits high elongation means it can stretch a lot before reaching its breaking point compared to mulberry silk.

In contrast, mulberry silk does not show as pronounced a yield point and has lower elongation compared to tussar silk. This implies that mulberry silk is less flexible and may have a more limited ability to stretch before breaking compared to tasar silk.

Why there is a difference in their properties

One answer can  be density.  The density of mulberry is higher ( 1.35 g/cc) as compared to tussar ( 1.30 g/cc). This suggests a relatively poor degree of orientation and less order in Tussar, which gives to lower modulus and elongation behavior of tussar.

These values have their commercial and functional implications. 

Can Silk be Machine Washed



At least a study suggests so. 

A paper titled "Study of property and structural variants of mulberry and Tussar silk filaments" by professor Mohan Gulrajani has suggested this idea. 

Earlier research suggested that the wet strength of silk specially Mulberry reduces considerably when subjected to water during laundering. This happens because in an aqueous environment, the hydrogen bonds between the molecules break. These bonds are crucial for maintaining the structure and strength of the fibers.

However the paper suggests that " silks can be machine washed at 40-60ºC provided one uses appropriate washing procedures, such as the use of neutral detergents".

The results for both Tussar and Mulberry found that " the tenacity and elongation at break are not
significantly different in dry or wet state ". However there is slight decrease in modulus. The figure given below talks about the result. 






A reduction in modulus would make the fiber less stiff.

Modulus, specifically in the context of materials science, refers to the measure of a material's stiffness or rigidity. It indicates the ability of a material to resist deformation under an applied force. Modulus is typically expressed in terms of stress divided by strain, where stress is the force applied per unit area, and strain is the resulting deformation.

When the modulus of a material decreases, it means that the material becomes less resistant to deformation for a given stress. In other words, it becomes more flexible or less stiff. Conversely, an increase in modulus would indicate that the material becomes stiffer or more resistant to deformation.

Then why it is not advised not to launder Pure silk sarees ?

The answer lies in the properties of commercially available silk fabrics or sarees. The above study was done after fully degumming the yarn. However, in commercially available silk fabric, the yarn is not fully degummed, there is always a residual gum or sericin. In the study about 20% sericin was found in mulberry and 5% in tussar.  On wetting, the sericin weakens, and allows inter filament slippage, which in turn leads to a drastic reduction in mechanical properties. Hence the strength of the wet silk gets reduced. 

What is sericin, what is silk fiber composed of ?

Silk fiber is primarily composed of two main proteins: fibroin and sericin. These proteins are produced by specialized glands in the silk-producing organisms, such as silkworms (Bombyx mori). The composition of silk fiber can vary depending on factors such as the species of the silk-producing organism and the conditions under which the silk is produced.

Fibroin: Fibroin is the structural protein that forms the core of silk fibers. It constitutes the majority of the silk fiber's mass and is responsible for its strength and resilience. Fibroin is a fibrous protein composed mainly of amino acids such as glycine, alanine, and serine. The exact composition and arrangement of amino acids within fibroin contribute to its unique mechanical properties, including its tensile strength and elasticity.

Sericin: Sericin is a glue-like protein that surrounds and binds the fibroin filaments together within the silk cocoon. It serves to protect the fibroin and provide cohesion to the silk fiber structure. Sericin is composed of various proteins and amino acids, with its composition varying depending on factors such as the silk-producing species. Sericin is typically removed from silk fibers during processing to improve their texture and appearance, leaving behind only the fibroin core.

In addition to proteins, silk fiber may also contain small amounts of other substances such as lipids, sugars, and minerals. These minor components can influence the properties of silk fibers but are present in much smaller quantities compared to fibroin and sericin.

Some Notes about Arani Sarees



 Source

1. Until 1995, only small motifs were created using 'Adai' or dobbies. Now bigger motifs with Jacquards are also in vogue.

2. Arani is located in the Tiruvannamalai district of Tamil Nadu.

3. In Tamil, Aru means river and Ani means adorning. Arani means a place made beautiful by rivers.

4. In Arani, still street sizing is practiced

5. These sarees are characterized by Korvai and Thazhampoo Rekku on the borders. 

In Hindi, "Thazhambu flower" is known as "केवड़ा फूल" (Kewda Phool). Kewda is a type of fragrant flower commonly used in perfumes, culinary preparations, and religious rituals in India. It is also known as Pandanus flower in English.

In the context of sarees, "ரேக்கு" (rekku) typically refers to the decorative borders or edges of the saree. These borders are often woven or embroidered onto the saree fabric and can vary in width and design. The term "rekku" is used to describe these intricate patterns or embellishments that adorn the edges of the saree, enhancing its beauty and elegance.


Thazhambu Flower

Thazhampoo Rekku

6. Both Frame looms and pit looms are used to weave the sarees. 

7. Arani weavers are mostly composed of Saurashtrians from Gujarat who came during the Vijayanagara Period. 

8. Arni Dobby sarees are lightweight and made with single color yarn using a fly shuttle. 

9. This region also produces Kumbakonam korvai Sarees

Kumbakonam Sarees

10. Arani Kottadi ( Checked pattern is very Popular)



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