Today's KNOWLEDGE Share:Waste Metals

Today's KNOWLEDGE Share:

Waste Metals

Half of all the metals used today have a lifespan of fewer than 10 years.

As a society, we use around 61 different metals.However, more than half of them will end in a landfill or in a recycling yard within ten years.This speaks to the enormous amount of wastage that we accrue as a civilization.

Billions of tonnes of metals are mined each year, which accounts for 8 % of all greenhouse gas emissions. Now, if we could save the metals that we discard, it could bring down both mining and greenhouse gas emissions.

The results are from an industrial ecology group at Yale University.

The only notable exception to this list is gold, which continues to be maintained and reused for centuries.Perhaps we should start mandating metal recycling and make it profitable to extract waste metals from landfills.

Source:http://ow.ly/7iNj50JmBGh

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#metals #wastemanagement #landfills #gold #mining #co2emissions

Today's KNOWLEDGE Share:Earthquake Effect on Spherical Storage Tanks

Today's KNOWLEDGE Share:

Earthquake Effect on Spherical Storage Tanks:

A major earthquake of magnitude 9 (Richter scale) hits eastern Japan at 14:46, a leak on a LPG pipe is detected at 15 h 35 in a refinery located within a large petrochemical complex in the bay of Tokyo . At 15 h 48, the leak ignites and spreads to the adjacent spherical tanks stocking liquefied butane and butylene.
The rapid development of the fire causes the fall of most tanks (broken foot support) and a cascade of BLEVE (BOILING LIQUID EXPANDING VAPOUR EXPLOSIONS).

The initial leak of LPG, by crushing of a pipe, resulted from the collapse of an overhanging sphere filled with water for a hydraulic test after the 1st aftershock of the main earthquake.
The main earthquake weakened the supporting structure by cracking the crosspieces, and then led to the failure of the support legs during the 1st aftershock of magnitude 7.2 at 3.15 pm.

What Went Wrong???
The design of the structure adapted to the seismic risk for a gas (LPG) load did not take into account the overload due to the filling of the tank with water.
In addition, the automatic safety shutdown of the gas transport pipeline triggered by the seismometers was inoperative on this part of the pipeline, as the automatic cut-off valve was shunted open following earlier problems with the pneumatic control.(big mistake).The temporary procedure of manually closing this valve pending repair could not be implemented due to a large LPG pool.
As a result, the fire was uncontrollable.

What We Learned From This Accident?
-Reduction of the duration of the water presence in the spheres in hydraulic tests (judged abnormally long during the accident) ;
-In the new sphere design, additional loads from water, especially seismic loads, should be taken into account.
-Systematic isolation and draining of a gas pipeline close to the spheres under hydraulic test.
-Increasing the flexibility of new on site gas transport pipelines to accommodate large multidirectional displacements during major earthquakes.
- Emergency shut-off valves are critical equipment, their faults should be repaired in a short time.

Source:https://lnkd.in/dNpCnuw4/ Technical Engineering Portal
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#LPG #sphericaltanks #fire #earthquake #seismicloads #oil #chemical #propane #butane #butylene #Bleve #gas #refinery #petrochemical #engineering #safety #design #pipeline
#development #transport

Today's KNOWLEDGE Share: Integral Hinge Material Characteristics

Today's KNOWLEDGE Share:

Integral Hinge Material Characteristics:
I have worked on a number of projects, both material selection and failure analysis, involving an integral hinge. An integral hinge, also known as a living hinge, is a thin flexible web that connects two relatively rigid wall sections. The living hinge is formed when partially oriented plastic is drawn cold and flexed for the first time. Because of its molecular structure and flexural fatigue properties, polypropylene is widely used in integral hinge applications. Well oriented polypropylene webs are considered to have virtually unlimited fold endurance, assuming appropriate part design, resin, and molding conditions are utilized.

When reviewing the commercially available polypropylene resins, it is helpful to consider which compositional characteristics maximize the material’s utility for a living hinge application.

Typically, fillers and reinforcements compounded into polypropylene will negatively impact the performance of the integral hinge. Fillers and reinforcements reduce the elongation at yield of the material, which accounts for this reduction in performance.

A superior molded integral hinge relies on the ability to freeze polymer orientation during molding prior to cold drawing. A number of polymer variables affect the amount of frozen orientation.

Molecular Weight: High molecular weight is desirable in a living hinge application. However, lower melt flow rate resins can be more difficult to mold properly.

Molecular Weight Distribution: A polypropylene resin with a broad molecular weight distribution results in superior integral hinge performance. Longer polymer chains cannot relax as easily as short chains.

Nucleation: Nucleation enhances hinge quality by accelerating the process of freezing the polypropylene orientation. However, it is important to note that if there is melt flow hesitation, nucleation will reduce the performance of the integral hinge. It is very important that the material, and molding parameters be balanced to produce an optimally functional integral hinge.

Polymer Type: Given their higher tensile strength, polypropylene homopolymers generally produce better integral hinges. Homopolymers are characterized by relatively high stiffness, even at elevated temperatures. However, they exhibit brittle behavior at temperatures below 5 °C (41 °F). Polypropylene random copolymers exhibit excellent transparency, and offer reduced stress whitening within the hinge. They generally exhibit cold temperature performance that is better than homopolymers. Polypropylene heterophasic copolymers (block copolymers or impact copolymers) are characterized by good impact properties down to temperatures below freezing.

Source:The Madison group
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#plastics #polymerscience #polypropylene #hinge #design #impact

Today's KNOWLEDGE Share: Why are Charcoal and Salt Added in the Earth Pit?

Today's KNOWLEDGE Share:

Why are Charcoal and Salt Added in the Earth Pit?

The combination of salt and charcoal is the perfect mixture which makes the ionic bonding for moisture in the earth pit. When the moisture increases in the soil, it increases the conductivity of the earth or ground conductor to the grounding rod or earth plat buried in the earth pit. That’s why the mixture of charcoal and salt is the best combination to put in the earth pit to maintain the low resistance.

An alternate layer of salt and charcoal is used to increase the effective area of the earth which leads to decrease the earth’s resistance.

As discussed above, the mixture of salt and charcoal as an alternate layer in the earth pit absorbs the moisture from the soil and surroundings. Additionally, the salt makes a perfect bonding with water, soil and charcoal. Therefore, the combination of charcoal and salt decreases the resistance and increases the conductivity of the earth pit. This way, the fault current can easily flow from the metallic body of the machine through the grounding conductor (earth continuity conductor) to the earthing lead and earth electrode (earth plat) buried in the earth pit.

The mixture of coal and powdered charcoal can maintain the moisture around the soil for a long time period. Hence, it reduces the resistance of earth pit and soil. This way, in case of fault, a less resistive path is available for fault current to flow to the ground. Thus, it provides proper protection to electrical machines as well as against the electric shock to a human body in contact with the metallic body of electrical appliances.

As the resistances may vary according to the different types of soil, thus it is important to check and test the conductivity of the soil before making an earth pit for grounding rods and earth electrodes (generally GI pipe or plate).

Keep in mind that the minimum and ideal resistance of the earthing and grounding system should be at least 1 Ω. If the resistance is more than 1-5+ ohms, you may increase the size of earthing lead and earth continuity conductor. Make sure to put water from time to time in the GI pipe connected to the earth pit which makes sure proper moisture around the earth plat. Hence, the earthing & grounding system for protection purposes works smoothly.

Source:Technical Engineering Portal (Linkedin)

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#charcoal #salt #earth #conductivity #conductor #electrode

Today's KNOWLEDGE Share: History of fiberglass

Today's KNOWLEDGE Share:

History of fiberglass

The use of fiberglass dates back to 1836 when Ignace Dubus-Bonnel received the world’s first patent on a method of making them. At the time, fiberglass was hard to make thin enough to be completely flexible, and no reliable method of mass production existed. 

These problems would only be solved in 1932 by Dale Kleist, a graduate student who was working part-time at Owens-Illinois as a researcher. The company wanted to make glass blocks for architectural use, and its researchers were looking for a way to seal the two halves of a block together so that moisture couldn’t get inside. 

He decided to try a metal-spraying gun with molten glass instead of bronze and discovered that it created a shower of ultrafine, thread-like glass fibers. Owens-Illinois immediately recognized that this was an excellent way to make glass wool for insulation and that it might be adaptable for other applications. 

Four years and the researchers were turning out individual strands long and flexible enough to be woven into cloth. The cloth was remarkably strong, and it could be cut and folded just like ordinary fabrics. 

Source:

The Fiberglass Story, written by Michael Lamm/

#managingcomposites

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#fiberglass #composites

Today's KNOWLEDGE Share: Valve Liner Cracking

Today's KNOWLEDGE Share:

Valve Liner Cracking

I recently wrapped up a failure analysis on a valve liner that had cracked while in service. The valve liner had been machined from perfluoro alkoxy (PFA). In this case, almost no background information was available on the valve application. My client was several steps removed from the installation. This can significantly hamper the failure analysis, limiting the ability to interpret test results.

The visual examination revealed a significant level of rust and adherent gritty debris on the valve liner. A circumferential crack was present within a design corner of the plastic liner. The cracking exhibited a continuous irregular crack pattern indicative of multiple radial cracks, not a circumferential crack. No signs of macro ductility were apparent, and the observed features were characteristic of brittle fracture.

The fracture surface displayed features indicating multiple individual cracks initiating at the liner design corner. The cracking extended radially into the part wall, and the coalescence of the individual cracks formed the circumferential fracture orientation.

The scanning electron microscopic (SEM) examination confirmed the presence of multiple crack origins, separated by ridgelike features corresponding to crack unions. A significant level of micro ductility was apparent within the crack origins, as indicated by stretched flaps. Striation bands of stretched flaps corresponding to progressive crack propagation were evident extending out from the crack origin area. The features were characteristic of dynamic fatigue. These features extended out from the origin through the mid-crack fracture surface. On the opposite wall of the liner from the crack origins, a significant level of stretching and deformation was apparent. This represented substantial micro ductility, and corresponded to mechanical overload within the final fracture zone.

Overall, the fractographic evaluation indicated that the valve liner failed through dynamic fatigue associated with alternating cycles of cracking and arrest. Based upon the observed striations, it is thought that this was low cycle fatigue, less than 10,000 cycles. However, such assessments can be erroneous, as crack initiation can account for up to 80% of the cycles.

Analytical testing including Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) produced results characteristic of a PFA resin, with no indication of material irregularities.

Background information detailing the service conditions would have been helpful to identify the source of the stress responsible for the failure, as well as contributing environmental factors.

Source:The Madison Group

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#plastics #failureanalysis #cracking #pfa #valves #fractography #sem #dsc

Today's KNOWLEDGE Share: Nanoparticle in carbon fiber composites

Today's KNOWLEDGE Share:

Nanoparticle in carbon fiber composites

Check out this amazing microscopy! 

This picture shows residues of a nano particle toughened epoxy matrix adhering to a fractured carbon fiber! 

Source: Leibniz-Institut Für Verbundwerkstoffe

#managingcomposites

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#composites #carbonfiber #epoxy #microscopy