Today's KNOWLEDGE Share: EV BATTERY:

Today's KNOWLEDGE Share:

EV BATTERY:

Although lithium-ion batteries have high energy density and cycle life, the cost and safety of the batteries limit their widespread use in this field. Sodium-ion batteries not only have high safety and cycle life, but also have obvious advantages over lead-acid batteries in terms of energy density, making them a good alternative to lead-acid batteries in the field of low-speed electric vehicles. In the low-speed vehicle market, sodium-ion batteries are cost-effective and competitive. The low-speed vehicle market does not require high energy density and the performance of sodium-ion batteries is sufficient to meet the needs of low-speed electric vehicles.

After determining the standard for miniature low-speed pure electric passenger vehicles, the majority of car companies have clear goals, and they have tried to slice the cake in the low-speed electric market and launched low-priced A00-class electric vehicles. Beginning in July 2020, China has organised new energy vehicles to the countryside for three consecutive years. Among them, A-class and A00-class pure electric vehicles have become the main models for going to the countryside.

Low-speed vehicles and A00-class electric vehicles have low cruising range and low requirements on the energy density of power batteries. In 2018, Zhongke Haina launched the world's first low-speed electric vehicle driven by a sodium-ion battery (72V, 80Ah), opening up the world's first low-speed electric vehicle driven by sodium-ion batteries.

At present, there is a strong demand for short-distance transportation such as picking up and dropping off students to and from school and short-distance shopping in urban areas. With the acceleration of urbanisation in rural areas, road transportation facilities are gradually improving, and the demand for motorised travel is increasing. Against the background of stricter regulations and rising cost of lithium-ion batteries, sodium-ion batteries are expected to develop rapidly in the field of low-speed vehicles and A00-class vehicles.

Source:Brendan Jephcott

Visit MY BLOG http://polymerguru.blogspot.com

#ev #evbatteries #evchargers #lithiumionbatteries #sodiumionbattheries

#electricvehicles #alternativeenergy #carbonneutral #batteries #energy #safety #travel #transportation

Today's KNOWLEDGE Share:Composite materials in 13th Century

Today's KNOWLEDGE Share:

How composite materials helped to enable the Mongols military dominance during the 13th century? 

The use of composite materials in military equipment started much earlier than you think! 

In about 1200 AD, Mongols invented the first composite bows made from a combination of wood, bamboo, bone, cattle tendons, horns, and silk bonded with natural pine resin. These small, powerful and extremely accurate bows were the most feared weapons on earth until the 14th century invention of effective firearms. 

Composite Mongolian bows helped to ensure Genghis Khan's military dominance during that period, in which its arsenal conquered huge chunks of central Asia and China! 

History shows us how the mastery of advanced materials has been extremely important, even for ancient civilizations! 

Source:#managingcomposites #thenativelab

Visit MY BLOG http://polymerguru.blogspot.com

#composites #bow #military #mongolia #china #asia

Today's KNOWLEDGE Share:21st century concrete

Today's KNOWLEDGE Share:

21st century concrete: composite metamaterial with super compressibility, energy harvesting!

"A new study introduces the use of metamaterials in the creation of concrete, making it possible for the material to be specifically designed and tailored in its attributes such as load-bearing capability, flexibility and shapeability. These can be fine-tuned in the creation of the material, enabling builders to use less material without sacrificing strength or durability." 

“This project presents the first composite metamaterial concrete with super compressibility and energy harvesting capability,” said Alavi. “Such lightweight and mechanically tunable concrete systems can open a door to the use of concrete in various applications such as shock absorbing engineered materials at airports to help slow runaway planes or seismic isolation systems.” 

"The material is also capable of generating electricity — not enough to send power to the electrical grid, but more than enough to power roadside sensors. The electrical signals self-generated by the metamaterial concrete under mechanical excitations can also be used to perform structural health monitoring (SHM), measuring damage inside the concrete structure or to monitor loads and stresses during earthquakes." 

Source:#Managingcomposites

Visit MY BLOG http://polymerguru.blogspot.com

#composites #metamaterials #concrete #electricity #electricgrid

Today's KNOWLEDGE Share: Crystallization kinetics

Today's KNOWLEDGE Share:

How does crystallization kinetics possibly influence the PvT data we use in all our molding simulations ?

PvT are typically obtained, in theory, under "thermodynamic equilibrium" conditions. This means at speed so low that kinetics should be irrelevant.

The molding process is the complete opposite ! Very fast cooling will shift crystallization T to lower values. And, as also depicted in the figure, the solid state density will be lower (so specific volume, the Y axis, higher for the red curve).

Implementing crystallization kinetics in Flow Simulation is therefore quite a big challenge since cooling rate will be different from part to part, molding condition to molding condition, as well as within the same part (thin vs. thicker areas cool at different rates for instance and temperatures are different throughout the melt).

People who have attempted to implement such "dynamic PvT" or "fast PvT" often neglect to account for the extremely strong nucleating effect of shear-stress in the outer layers. Any DSC (quiescent) crystallization kinetic data will fail to predict the true kinetics observed under the very high flow stresses of Injection Molding.

Pressure is also a well known nucleating "agent" (speeding up crystallization, as seen in the classical horizontal shift of the transition zone in PvT data) but will also increase the Glass Transition temperature of the material which results in the opposite effect of slower molecular diffusion (higher viscosity) and hence somewhat slower crystallization.

Quite some work ahead of us to further improve the accuracy of Injection Molding without actually deteriorating the simulation performance by forgetting important pieces of this complex Physics !.

Source:VITO LEO

Visit MY BLOG http://polymerguru.blogspot.com

#plastics #polymerscience #injectionmolding #temperature #crystallization #thermodynamics #simulation #flow #stress

Today's KNOWLEDGE Share:Natural Fiber Composites:

Today's KNOWLEDGE Share:

Natural Fiber Composites:

Composite materials have found applications in virtually all markets, from bathtubs to spaceships. In some markets, composites are still the newcomer, while in others, the hard-earned reputation of composites is well established.

Across their varied applications, composites are commonly chosen because they are considered “high-performance” materials. In the materials industry, earning the title of “high-performance” typically demands high strength, high stiffness, and low weight. We combine these attributes when we examine the specific properties, or the strength-to-weight and stiffness-to-weight performance of the material. The higher the specific properties, the more demanding applications we can expect to address.

In recent years, consumers have begun to demand not only high performance, but also improved sustainability and reduced environmental impact. We believe the material champions of the future will combine high specific properties with environmentally responsible feedstocks and processes.

One promising approach to meeting both of these demands lies in the adoption of plant-based reinforcements from sources such as jute, sisal, flax, hemp, kenaf, and pineapple to produce Natural Fiber Composites (NFCs). These reinforcement fibers have been found to have competitive properties, especially specific stiffness, compared to glass fibers (1,2).

Plant-based fibers have a long history of use as both fillers and reinforcements—from ancient builders reinforcing clay with straw to modern marine engineers using flax fibers to build performance yachts. Natural fibers are widely known and appreciated for their sustainable nature, biodegradability, and low carbon footprint.

For instance, life cycle analyses have calculated the production of flax fibers can result in greenhouse gas emissions below 1.0 kg CO2e per kg of flax fiber (3), while carbon fiber production results in up to 31 kg CO2e per kg of carbon fiber (4). This is <5% compared to carbon.

Natural fibers also present challenges compared to their synthetic counterparts. Man-made fibers such as carbon, glass, Kevlar, and basalt fibers are manufactured by steady, well-controlled processes which deliver a consistent and uniform product. Natural fibers, however, reflect the variations of the biological processes which produce them, resulting in less consistent fiber form and length, and sensitivity to high temperatures. These characteristics result in processing challenges that prevent natural fibers from being drop-in replacements in many applications.

ARRIS Composites’ Additive Molding technology is already pushing the boundaries on low-waste manufacturing of high-performance products.

Source:Compositesworld/Arris composites

Visit MY BLOG http://polymerguru.blogspot.com

#composites #naturalfibers #flax #stiffness #additivemanufacturing

Today's KNOWLEDGE share:BAMBOO FIBER:

Today's KNOWLEDGE share:

BAMBOO FIBER:

Bamboo fiber yarn is a type of cellulose fiber extracted from the natural growth of bamboo and is the fifth natural fiber after cotton, hemp, wool, and silk. Bamboo fiber yarn has good breathability, instant water absorption, strong wear resistance, and good dyeing properties. It also has natural antibacterial, bacteriostatic, mite removal, odor resistance, and UV resistance functions. Bamboo fiber yarn textile products are highly favored by consumers due to their inherent properties, and the demand for these products continues to increase each year.

THE COMPOSITION OF BAMBOO FIBER

The chemical composition of bamboo fiber, also known as bamboo viscose, mainly consists of cellulose, hemicellulose, and lignin, all of which are polysaccharides and account for over 90% of the dry weight of the fiber. The other components include proteins, fats, pectin, tannins, pigments, and ash, most of which are located in the cell lumen or specialized organelles.

The cellulose content of bamboo varies depending on the age of the bamboo. For example, young bamboo may have a cellulose content of 75%, while one-year-old bamboo may have a content of 66%, and three-year-old bamboo may have a content of 58%.

THE CLASSIFICATION OF BAMBOO FIBER

Natural Bamboo Fiber :

Bamboo Original Fiber is a natural bamboo fiber made using a combination of physical and chemical methods.

Bamboo Original Fiber is a new type of natural fiber, made using a combination of physical and chemical methods. It differs fundamentally from bamboo pulp fiber, which belongs to chemical fibers. The successful development of Bamboo Original Fiber marks the birth of a new natural fiber that is in line with the national industry development policy. Natural Bamboo Original Fiber has excellent properties such as moisture absorption, breathability, antibacterial and deodorizing effects, and UV protection.

The production process includes the steps of bamboo logs → bamboo chips → steaming of bamboo chips → crushing and decomposition → biological enzyme degumming → fiber combing → textile fiber.

Chemical Bamboo Fiber -Bamboo Pulp Fiber:

Bamboo pulp fiber is made by turning bamboo chips into pulp, then making pulp into pulp cakes and wet-spinning them into fibers. The production process is similar to that of viscose. However, the natural characteristics of bamboo are destroyed during the manufacturing process, and the fiber’s deodorizing, antibacterial, and UV protection functions are significantly reduced.

Chemical Bamboo Fiber -Bamboo Charcoal Fiber:

Bamboo charcoal fiber is made by adding nano-grade bamboo charcoal powder to viscose spinning solution and then spinning the fiber using a process similar to conventional spinning.

Source:Socks Industry International Co.Ltd

Visit MY BLOG http://polymerguru.blogspot.com

#bamboo #naturalfibers #bambooproducts #carbonneutral #sustainability #greeneconomy #textileindustry #textile #spinning #socks #suits #clothing