Fiber-reinforced concrete is a concrete mixture that is reinforced with randomly oriented fibers. Depending on the project and the environmental impact that may affect the concrete, there are a wide variety of fibers that will specifically fit the needs of your specific project. Some of the available fiber types are as follows.Available fiber products for concrete reinforcement from Euclid Chemical are "grouped" PSI Fiberstrand Fibers, TUF-STRAND Macro-Synthetic Fibers, and PSI Steel and Blended Fibers.The Euclid Chemical Company
SoFi Stadium is the home to the Los Angles Rams and Los Angeles Chargers football teams. The stadium seats 70,240 spectators for most events, with the ability to expand it with 30,000 additional seats for larger events. It is located at the former site of the Hollywood Park Racetrack in Inglewood, 3 miles (4.8 km) from Los Angeles International Airport. TUF-STRAND SF at a dosage of 5 lb/yd (3 kg/m) was used as the reinforcement in topping slabs for the upper-level decks of this facility. These fiber-reinforced slabs, as opposed to conventionally reinforced slabs, will not have the potential for corrosion over the lifetime of this facility. TUF-STRAND SF synthetic macrofiber was also used to provide improved crack control for this topping slab. Additionally, construction time was reduced as the use of TUF-STRAND SF eliminated the time to crane lift and install welded wire fabric or reinforcing steel, and job-site safety was improved by eliminating a potential tripping hazard for the concrete placement crew.
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Conditions that are mostly affected by the use of aggressive shampoos are: Difficulty in untangling the strands, and the frizz effect. Attrition, the main cause of frizz, can be minimized by adequate formulation of cleaning products. On the other hand, if the shampoo formulas do not present the adequate composition, fiber attrition is aggravated.[10,16]
It is common to use cationic ingredients in many shampoos' formulations with anionic surfactants in order to result in charge neutralization forming a cationic-anionic complex, a neutral hydrophobic ingredient. Therefore, we can understand that the interaction between the ingredients is more important than the ingredient alone, as we are led to believe by the media. It is very common to think that a new release product that contains a certain ingredient has the magic ability to transform dull hair into shiny and smooth hair. Most of the time, the major ingredients do not change, and sometimes the capacity of the ingredients to interact inside the shampoo's or conditioner's chassis or system is what makes the product acts better. Bleached and chemical treated hair have a higher affinity to conditioning ingredients because they have a low isoelectric point (higher concentration of negative sites) and are more porous than virgin hair.[5,20]
Polysiloxane polymers may re-cement lifted cuticle scales and prevent damage from heat. Amino functional silicones are cationic substances but not necessarily are more substantive to the hair than dimethicone, depending on the size of the molecule and the charge of the system. Dimethicones are hydrophobic, so they adsorb better on virgin hair and root rather than tips. To enhance the deposition of dimethicone on chemical treated and damaged hair the products use cationic bridging agents which act increasing affinity between hair and the silicone.[4,5,12,24,23]
Oils play an important role in protecting hair from damage. Some oils can penetrate the hair and reduce the amount of water absorbed in the hair, leading to a lowering of swelling.[26] This can result in lower hygral fatigue (repeated swelling and drying), a factor that can damage hair. The oil can fill the gap between the cuticle cells and prevent the penetration of the aggressive substances such as surfactants into the follicle. Applying oil on a regular basis can enhance lubrication of the shaft and help prevent hair breakage. Rele and Mohile in 2003, studied the properties of mineral oil, coconut oil and sunflower oil on hair.[27] Among three oils, coconut oil was the only oil found to reduce the protein loss for both undamaged and damaged hair when used as a prewash and postwash grooming product. Both sunflower and mineral oils do not help in reducing the protein loss from hair. This difference in results could arise from the composition of each of these oils. Coconut oil, being a triglyceride of lauric acid (principal fatty acid), has a high affinity for hair proteins and because of its low molecular weight and straight linear chain, is able to penetrate inside the hair shaft. Mineral oil, a hydrocarbon, does not penetrate. Sunflower oil is a triglyceride of linoleic acid with a bulky structure and double bonds and has limited penetration to the fiber, not reaching the cortex. The mineral oil and the sunflower oil may have a film effect and adsorb to the surface of the cuticle enhancing shine and diminishing friction and for these, avoid hair damage.[22]
The small angle of the waves of very curly hair makes it more susceptible to breakage, when mechanically worked making curly hair more difficult to comb without provoking frizz. Although the production of sebum is high on African hair, curly and wavy hair they are more prone to have oily scalp but dryer hair fiber. Sebaceous glands of African descendants are frequently less active, when compared with the Caucasian ones, and they produce low amounts of sebum. This way, both scalp and threads are dry because they do not have good lubrication, even when the cuticle is preserved and the scalp tends to be less hydrated. Usually, the scalp is relatively dry in order to the naturally irregular distribution of sebum.[7] Distribution of sebum along the fibers by combing and brushing is a way of lubricating curly hair because of the natural difficulty of the sebum produced on the scalp to diffuse along the fiber.[5,7,36]
Fine straight hair can transport sebum very well, and curly-coarse hair tend to minimize tress clumping and limpness. The use of conditioners and leave-on products decrease interfiber friction making hair easier to comb. Chargeability also decreases helping to improve dry combing.[4,5,6]
We know that split ends are more likely to occur in weathered and oxidized hair. But, split ends happen when the cuticle is removed (damaged) and the cortex-cortex CMC serves as a route for the propagation of axial splits in the fiber, leading to the formation of cracks and split ends. Hair strength depends on cuticle integrity and amount of water in the fibers, conditions that are related to chemical damage. Chemical damage by bleaches, dyes, straighteners and even sunlight can weaken hair and increase inter-fiber friction, leading to breakage. An important factor involved in hair breakage is the occurrence of tangles created by combing forces. Where the break occurs along the fiber, correspond to the point of higher combing forces. The type of fracture depends on hair condition and wet versus dry combing or brushing. Combing dry hair is more related to short segment breaks, and wet combing is related to long segment breaks. The short segment breaks are more related to split ends. Straight to wavy hair combed dry, produces higher end pick forces than mid-length forces, but when wet, produces higher mid-length combing forces corresponding to where hair breaks and to the amount of breakage. The work of combing highly coiled hair is lower wet than dry. The reverse holds for wavy to straight hair. Split ends form more readily from the abrasion (friction) in combination with torsional deformations (grooming and styling). Splitting occur when the cuticle is damaged and weakened. Crack is formed in the cortex. Few cuticle layers do not hold the ends of the hair fiber together. Also, highly oxidized cortex cell membrane by free radical chemistry is more susceptible to split. Hair treated with free radical cosmetics and exposed to sunlight is susceptible to splitting.[5,8,38]
Hydroxides and thioglycolate are incompatible with each other. If the hair is treated with hydroxides the same hair cannot be treated with thioglycolate. Also, both are incompatible with bleached hair. So, it is not unusual to receive a patient complaining that the hair broke (hair shed because of hair breakage) after the use of a relaxer. To avoid mistakes like that, the salon professional must perform a test that consists on the application of the product on a strand of hair to prove compatibility. If the hair breaks during the test, another relaxer must be tried, or the hair is too weak to be straightened. Hair conditioning substances may be added to thyoglicolate straighteners in order to minimize hair damage.[48,53]
The use of formaldehyde formulations became very popular since 2003, and the first country to start this practice was Brazil in Rio de Janeiro. The most used products, a decade ago, were based on a solution or cream containing a home-made formaldehyde formulation obtained from a mixture of conditioners, hydrolized protein and a 37% formaldehyde solution, easily obtained as an over-the-counter substance, sold in every drugstore in Brazil. The formaldehyde solution was commonly used to sterilize medical materials and hospitals, and easy to find in every drugstore. The practice soon became so popular that called attention of the health vigilance organizations in Brazil (ANVISA) that prohibited the use of any product containing formaldehyde in concentrations above 0.2% for cosmetics and 5% for nail polish. Afterward, the formaldehyde was replaced by a potentially 10 times more mutagenic and the neurotoxic product belonging to the same aldehyde group: The glutaraldehyde. Easily obtained from hospitals and clinics, glutaraldehyde was commonly used as a sterilizer. It was soon not a home-made product anymore, but a demi-industrialized nonlegal substance, commercialized in every salon in Brazil. The solutions came in beautiful colored bottles of 500 ml to 1 liter. The label carried a false ANVISA registration number, and the product was sold to the salons by door-to-door sellers.[54,55,56,57] 2ff7e9595c
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