Today's KNOWLEDGE Share : Reversible Fluid Mixing

Today's KNOWLEDGE Share

Reversible Fluid Mixing

What it shows:

Ink is squirted into a fluid and mixed in until it disappears. By precisely undoing the motions in the reverse direction, the ink becomes unmixed! The demonstration seems to defy #thermodynamics in that it appears that entropy decreases, but in actuality the reversible mixing is made possible by ensuring that the mixing/unmixing is done without turbulence.

The space between two transparent and concentric cylinders is filled with a viscous fluid (glycerine or Karo™ syrup). One or more lines of colored fluid are also injected into this fluid reservoir, parallel to the axis of the cylinder(s). When the inside cylinder is slowly rotated (by means of a crank) with respect to the outside cylinder, the lines of colored fluid become mixed with the rest of the fluid. Several revolutions renders the mixture completely clear and "mixed". If one now reverses the direction of #rotation, the colored fluid lines reappear by "#unmixing" after the same number of rotations in the opposite sense.

The design and operation of the apparatus ensures laminar flow. Diffusion processes are, of course, much much slower than the time scale of the demonstration. As one cylinder is rotated w.r.t. the other, one can simply think of layers of fluid being displaced without involving #turbulence, the boundary layer next to the inner rotating cylinder being displaced the most and the layer adjacent to the outside cylinder the least. #Counterrotation slips these layers back into place.

Setting it up:

The fluid should be of high viscosity. We have used glycerine or corn syrup. The apparatus capacity is 2.2 to 2.3 liters; thus about 5 bottles of Light Corn Syrup should suffice. It will be necessary to add some kind of preservative 1 to the corn syrup if you plan to leave it in the apparatus for extended periods. Mold does not grow in the glycerine, but glycerine costs about $50/gallon.

The #ink should have similar #viscosity to the fluid you use. A few drops of food coloring mixed into about 10 ml of fluid works well. A #verticalline" of colored fluid is squirted into the apparatus by means of a hypodermic syringe fitted with a large needle and long stainless-steel extension tube. Alternatively, a 5 ml volumetric pipette fitted with a pipette rubber squeeze-bulb also works well. After the demonstration, the dye can be thoroughly mixed (by a few dozen turns) so that the syrup (or glycerine) can be used again. This will give you many uses before you have to discard it.

References:

J.P. Heller, Am J Phys 28, 348-353 (1960). "An Unmixing Demonstration"

This reference provides the mathematical description (Navier-Stokes equations) of the mixing transformation in the geometry of the Couette viscometer, which is a similar geometry to our apparatus.

R. Brewer and E. Hahn, Scientific American, Dec 1984

Source:https://sciencedemonstrations.fas.harvard.edu

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#reversiblefuildmixing

FORVIA starts deliveries of hydrogen tanks from first mass production plant in France

Recently, type IV Hydrogen tanks* have started rolling out from FORVIA’s groundbreaking mass production plant in Allenjoie, France. This first-of-its-kind facility in Europe and North America aims to produce 100,000 tanks annually.

With hydrogen as a driving force behind the decarbonization of mobility and industry, FORVIA is committed to delivering safe and affordable #hydrogenstorage technology. By streamlining processes and excelling in industrialization, we will slash production costs by 5 between 2023 and 2025.

This plant will serve the automotive and hydrogen #distribution & #storage industries for the European market. Leading European customers such as #Stellantis, #Hyvia and #MAN have already placed their trust in us to deliver solutions for on-board mobility applications. The plant will also produce the Type IV tanks that make up the Large-Scale Hydrogen Storage Solution which will be delivered to AirFlow for distribution & storage application.

“FORVIA has reached a major milestone in its hydrogen history! With deliveries already underway and a robust order book, our Allenjoie plant sets a new benchmark. From tank manufacturing to complete storage systems, our mid-term capacity of 100,000 tanks per year demonstrates our commitment to mass production and operational excellence. We’re driving the safe, affordable hydrogen technology our society needs, meeting customer expectations and decarbonizing our future.” said Patrick Koller, CEO of FORVIA.

First plant in France to achieve “BREEAM Excellent” certification

The plant in Allenjoie symbolizes #FORVIA’s unwavering commitment to sustainability. Engineered with sustainability at its core, the plant consumes less energy and has received the prestigious #“BREEAM Excellent” certification in 2022. As the first plant in France and only the second in Europe to achieve this high-level sustainability certification, it serves as a blueprint for the deployment of the FORVIA’s global #productionstandards. Expansion plans in China, North America, and Korea are already in motion, solidifying our commitment to a decarbonized industry.

A major hydrogen player

Since 2018, FORVIA has invested over €380M in #hydrogentechnology development. We remain steadfast in our commitment to this promising market, which is expected to grow to €20bn in 2030. FORVIA and Symbio** have registered a cumulated order intake of 1.2bn€ aligned with the long-term ambition of FORVIA as a leader in hydrogen with revenues of €3.5bn in 2030.

Source:www.faurecia.com/jeccomposites

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#composites #carbonfiber #thermoplastic #thermoset #h2tanks #autoindustry

New Injection Molding Sensors Mend Process Deviations

Two new miniature #injectionmolding sensors will be showcased at the Kistler stand at #Fakuma in Friedrichshafen, Germany, from Oct. 17 to 21, 2023.

As more manufacturers embrace Industry 4.0 methods and equipment to drive #precision production with real-time process data, injection molding #sensors are an indispensable way to detect process deviations and adjust parameters.

The new #Kistler sensors are:

The 9239B miniature longitudinal measuring pin, which has a diameter of 2.5 mm, takes up little space when installed in an #injectionmold, and is protected against direct contact with the melt. Using a PiezoStar crystal grown by Kistler to measure pressure-induced compression of the mold during the process, this sensor measures cavity pressure indirectly. Capable of being mounted between 2 and 4 millimeters behind the cavity wall, this sensor is particularly valuable for the medical sector, as it leaves no marks on the manufactured plastic part.

The 4004A 3-mm-diameter melt pressure sensor can be used directly in injection nozzles and small extruders. With an operating and measuring range of up to 350°C, the 4004A allows manufacturers to implement quality control during high-temperature processing. The sensor is also suitable for #3Dprinting applications. For injection molding, the sensor is calibrated for a measuring range up to 2,500 bar, and for #additivemanufacturing up to 1,000 bar.

This level of precision in process monitoring is especially vital in the quest to create a robust circular economy, the company noted, especially as manufacturers use more recycled materials.

"It's clear that the use of recycled materials in #plastics manufacturing and processing will continue to increase," said Felix Früh, head of BU Plastics at Kistler. "But higher proportions of recycled material also have a negative impact on the stability of injection molding processes. The #viscosity of the melt changes, for example. Process monitoring systems based on cavity pressure detect these fluctuations immediately and compensate for them continuously during the process. This allows users to guarantee homogeneous part quality even if the material characteristics vary."

Additionally, Kistler will demonstrate firmware versions of its ComoNeo and ComoScout process monitoring systems, its Stasa QC Optimizer, and its AkvisIO IME (Injection Molding Edition) production data software.

Source:Plasticstoday/kistler

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Today's KNOWLEDGE Share :Stress-Cracking resistance in molded parts?

Today's KNOWLEDGE Share

Why would glass fibers possibly help with Stress-Cracking resistance in molded parts?

Fibers get strongly aligned in the flow direction by the shear stress, specifically in the frozen skin layers. The core section always shows some more orientation randomness. As a consequence a strong residual stress will appear, because the core "wants" to shrink more than the skin. This accounts easily for a 10-30 MPa stress in a stiff GF filled material (a fractional % of the modulus). The good news is that the core, desperately trying to shrink more, will put the skin under significant compression, protecting your part from Environmental Stress-Cracking, which can only operate in Tension.

Not very different from "rebars in concrete", if you see what I mean.

Source:Vito leo

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#plastics #polymerscience #injectionmolding #stresscrackingresistance #shrinkage #glassfiberfilled

Improving US air quality, equitably

Study finds climate policy alone cannot meaningfully reduce racial/economic disparities in air pollution exposure.

Decarbonization of national economies will be key to achieving global #netzero emissions by 2050, a major stepping stone to the Paris Agreement’s long-term goal of keeping global warming well below 2 degrees Celsius (and ideally 1.5 C), and thereby averting the worst consequences of climate change. Toward that end, the United States has pledged to reduce its #greenhousegasemissions by 50-52 percent from 2005 levels by 2030, backed by its implementation of the 2022 Inflation Reduction Act. This strategy is consistent with a 50-percent reduction in carbon dioxide (CO2) by the end of the decade.

If U.S. federal #carbonpolicy is successful, the nation’s overall #airquality will also improve. Cutting #CO2emissions reduces atmospheric concentrations of air pollutants that lead to the formation of fine particulate matter (PM2.5), which causes more than 200,000 premature deaths in the United States each year. But an average nationwide improvement in air quality will not be felt equally; #airpollution exposure disproportionately harms people of color and lower-income populations.

How effective are current federal #decarbonization policies in reducing U.S. racial and economic disparities in PM2.5 exposure, and what changes will be needed to improve their performance? To answer that question, researchers at MIT and Stanford University recently evaluated a range of policies which, like current U.S. federal carbon policies, reduce economy-wide CO2 emissions by 40-60 percent from 2005 levels by 2030. Their findings appear in an open-access article in the journal Nature Communications.

First, they show that a carbon-pricing policy, while effective in reducing PM2.5 exposure for all racial/ethnic groups, does not significantly mitigate relative disparities in exposure. On average, the white population undergoes far less exposure than Black, Hispanic, and Asian populations. This policy does little to reduce exposure disparities because the CO2 emissions reductions that it achieves primarily occur in the coal-fired electricity sector. Other sectors, such as industry and heavy-duty diesel transportation, contribute far more PM2.5-related emissions.

The researchers then examine thousands of different reduction options through an optimization approach to identify whether any possible combination of carbon dioxide reductions in the range of 40-60 percent can mitigate disparities. They find that that no policy scenario aligned with current U.S. #carbondioxide emissions targets is likely to significantly reduce current PM2.5 exposure disparities.

Source:MIT News

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Today's KNOWLEDGE Share :Henri Moissan-The Nobel Prize in 1906

Today's KNOWLEDGE Share

Henri Moissan-The Nobel Prize in 1906

Several generations of chemists had tried in vain to isolate #fluorine, notably by #electrolyzing phosphorus and arsenic fluorides, but Moissan was determined to find a way. His genius lay in the idea of turning the bath into a conductor by adding a molten potassium fluoride salt, KHF2. (Pure hydrogen fluoride, HF, could not suffice as its capacity as an electric conductor was too weak.) Moissan devised a platinum electrolyzer and lowered the reaction temperature of the electrolytic solution of HF + KHF2 to limit corrosion. The platinum electrolyzer was U-shaped and stopped with fluorite (CaF2) stoppers.The cathode and the anode were made of irridated platinum to provide better resistance to the fluorine. The traces of hydrogen fluoride were condensed at the end of the apparatus in a low-temperature trap and also by sodium fluoride. On June 28, 1886, a gaseous product was identified at the anode of the electrolyzer: Fluorine (F2) had been successfully isolated, thus resolving one of the most difficult challenges in the realm of #inorganicchemistry. The yellow-green gas obtained was highly toxic and proved to be a powerful oxidizing agent, causing organic materials to burst into flames on entering into contact with it and combining directly, and often violently, with almost all other elements.

Among his contributions to science, there is also his arc #furnace capable of reaching temperatures of 4,100 ° C, allowing the reduction of certain metals such as uranium, chromium, tungsten, vanadium, manganese, titanium and molybdenum.

Source:wiley.com

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DuPont’s EV Battery Adhesive Receives R&D100 Award

 DuPont announces that DuPont™ BETAMATE™ broad bake #adhesives for sustainable mass manufacturing of battery electric vehicles have won the 2023 R&D100 Awards in the Mechanical/Materials category.

The R&D 100 Awards, sponsored by R&D World Magazine, recognizes the 100 most innovative technologies of the previous year.

Offers Significant Energy Savings:

DuPont™ BETAMATE™ broad bake adhesives are a novel solution enabling sustainable #manufacturing of next-generation #electricvehicles through a significant reduction of the e-coat oven temperature. This solution provides significant energy savings while durably bonding the high mass underbody of EV body structures in the body shop.

In addition, BETAMATE™ broad bake adhesives provide excellent #corrosion resistance, enhance passenger safety, deliver high elastic modulus and tensile strength, maintaining the quality of the bond over the vehicle’s projected lifetime and with a #shelflife of at least six months.

“We’re honored to be recognized for our teams' unwavering commitment to excellence, helping our customers address their most pressing sustainability challenges – from clean water to #sustainable shelter to next-gen automotive,” said Alexa Dembek, #DuPont chief technology & sustainability officer. “Receiving these awards exemplifies the commitment and dedication our teams display every day to deliver essential innovations to thrive.”

Source: DuPont/specialchem

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