Troubleshooting Metalworking Fluids

Troubleshooting Metalworking Fluids

Materials Science, processes
Based on a two-part webinar series. Part 1: Operational Factors (TLT April 2022). The right fluid formulation, regular maintenance and communication between workers, managers and suppliers can prevent or solve a host of problems on the shop floor.Part 2: Field Problems (TLT June 2022).Identifying and solving metalworking fluid problems requires good recordkeeping, maintenance and housekeeping practices—and communication between workers, managers and suppliers.
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Nitrate Reduction Provides Insights into Evolving Electrode Structures

Nitrate Reduction Provides Insights into Evolving Electrode Structures

environment, Materials Science
JACS Spotlights April 19, 2022 Wastewater treatments that reduce nitrate to form ammonia not only remove nitrate pollutants, but the resulting ammonia can be used in a variety of industrially useful reactions. William Tarpeh and colleagues recently studied the interacting effects of electrochemical nitrate reduction and the evolving structure and performance of titanium electrodes during the reaction, and they found a way to characterize the two phenomena separately (DOI: 10.1021/jacs.2c01274).Titanium is an inexpensive, robust electrocatalyst, but the reasons for its catalytic performance have not been fully explained. Electrochemical nitrate reduction reconstructs titanium electrode surfaces and forms a water-stable titanium hydride surface layer that changes as the reaction proceeds. The researchers studied titanium hydride formation on titanium electrodes under controlled nitrate reduction reaction conditions and found that the presence or absence…
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New Superatom Is Both Stable and Magnetic

New Superatom Is Both Stable and Magnetic

energy, Materials Science
JACS Spotlights March 22, 2022 Superatoms are small symmetric clusters of atoms with electronic states bunched together into closely packed shells. Like their individual-atom counterparts, superatoms with filled shells have the greatest electronic stability. Typical stable octahedral transition metal chalcogenide clusters have a single set of filled electron shells and they have no net spin magnetic moment outside an applied field.Now, Amymarie Bartholomew, Xavier Roy, Shiv Khanna, and co-workers have theoretically predicted a new type of cluster that would uniquely combine high stability and a large spin magnetic moment (DOI: 10.1021/jacs.2c00731). This theoretical cluster has two subshells: one with 57 valence electrons and one with 50, optimal numbers of electrons to create a large gap between the highest occupied and lowest unoccupied orbitals. They synthesized this new cluster, [NEt4]5[Fe6S8(CN)6], which…
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Nanoparticle Assembly: Expanding the Realm of the Possible

Nanoparticle Assembly: Expanding the Realm of the Possible

emerging technologies, Materials Science
JACS Spotlights Feb. 22, 2022 Nanoparticles assemble themselves into a multitude of compositions and structures, and the range of possible applications appears almost limitless. Robert Macfarlane and co-workers give an overview of the history and current state of nanoparticle assembly research, focusing on assembly approaches and emergent properties of the resulting materials and summarizing future directions and challenges (DOI: 10.1021/jacs.1c12335). The simplest assembly process, uncontrolled aggregation of nanoparticles into disordered clusters or films, is used on an industrial scale to produce coatings. Supramolecular assembly techniques (in various stages of development) direct nanoparticles to form ordered patterns, self-healing nanocomposites, vesicles, micelles, or thin films. Light, magnetic fields, or biomolecular templates can direct nanoparticles to produce even more complex structures. The resulting materials interact with light, electrons, and magnetic fields in ways…
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New Polymers Survive a Loss of Protection

New Polymers Survive a Loss of Protection

Materials Science, processes
JACS Spotlights, Feb. 9, 2022 Sulfur-containing organic molecules called thiols and thiocatechols are used in a variety of reactions involving the formation of disulfide bonds, coupling to double and triple bonds, and attachments to metal surfaces. In contrast, their polymer counterparts, thiophenol-pendant and dithiocatechol-pendant polymers, tend to oxidize and form disulfide-cross-linked networks. This renders them insoluble in organic solvents, which in turn limits their practical application. Catechol-pendant polymers, their oxygen-containing counterparts, oxidize much slower, and they readily form coatings, adhesives, and self-healing materials. Jincai Li, Joseph Richardson, and Hirotaka Ejima recently reported the use of a protection–deprotection strategy that enabled them to synthesize the thiophenol-pendant polymer poly(4-thiostyrene), as well as the first synthesis of a dithiocatechol-pendant polymer─poly(3,4-dithiostyrene)─and the copolymer poly(3,4-dithiostyrene-co-styrene) (DOI: 10.1021/jacs.1c11479). Unlike former efforts at protection–deprotection synthesis, the deprotection…
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Artificial intelligence for real-world mechanical systems

Artificial intelligence for real-world mechanical systems

emerging technologies, Materials Science
Artificial intelligence offers a wealth of resources for solving complex problems, but accurate predictions and understandable results still require human participation.TLT Feature February 2022 Artificial intelligence offers a wealth of resources for solving complex problems in mechanical friction and wear--helicopter transmissions and gears that are deep inside large machines, for example. Accurate predictions and understandable results still require human participation, including assembling and curating databases in a form that AI can use. TLT February 2022
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Bacteria Become Tiny Catalytic Synthesis Vessels

Bacteria Become Tiny Catalytic Synthesis Vessels

emerging technologies, processes
/JACS Spotlights Jan. 26, 2022 Artificial metalloenzymes, made from protein scaffolds incorporating synthetic metal complexes, combine the versatility of transition-metal catalysts with the shape selectivity of enzymes. Until now, getting the metal complex into the cell has been difficult, and the reactivity of artificial enzymes in living cells has been limited. John Hartwig and colleagues use living cells of EcN, a non-pathogenic strain of E. coli, as reaction vessels to assemble artificial metalloenzymes that catalyze further chemical reactions (DOI: 10.1021/jacs.1c10975). An iridium-containing porphyrin enters the bacterial cells from the growth medium via a chromosomally encoded outer-membrane transporter. The resulting enzyme catalyst drives site-selective, enantioselective carbene insertion into benzylic C–H bonds. The authors also identify a new transporter that is more efficient at taking iridium porphyrins into the cell cytoplasm than…
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Organic Synthesis Method Goes Against the Flow

Organic Synthesis Method Goes Against the Flow

processes
JACS Spotlights, Jan. 5, 2022 Making more stable compounds out of less stable ones is nothing new, but going the other direction often requires multiple synthesis steps, harsh reaction conditions, and separating the desired products from the inevitable byproducts. Alison Wendlandt and co-workers have found a way around this obstacle, using a novel dual catalyst system (DOI: 10.1021/jacs.1c12043). Together with ultraviolet light, these catalysts convert conjugated alkenes and alkenes with double bonds in interiors of the carbon chains into their thermodynamically unfavored isomers: unconjugated, with double bonds between carbon atoms at the ends of the chains. To demonstrate the technique, the researchers synthesized a variety of natural products, including an estrogen receptor agonist and several chiral linalool and terpene derivatives and isomers. Photochemistry provided access to excited electronic states, enabling…
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An indomitable particle: Colloidal silica takes on extreme environments

An indomitable particle: Colloidal silica takes on extreme environments

environment, Materials Science
Colloidal silica stabilizes the ground under buildings during earthquakes and stops the spread of toxic pollutants below ground. It also preserves ancient carvings in the jungle, keeps the lenses and sensors aboard space vehicles clear and clean, and stands up to the hot, salty environment of petroleum and natural gas wells. It's being tested as a construction material for 3D printed houses on Earth and for missions to the Moon and Mars. My e-book for W.R. Grace and C&EN BrandLab (gated content, free registration required).
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The electric vehicle grease industry finds its bearings

The electric vehicle grease industry finds its bearings

emerging technologies, energy
Evolving grease formulations help smooth the transition toward electric vehicles. TLT November 2021 Electric vehicles don't require gasoline, but they do require grease. Existing greases are OK for windshield wipers, door hinges, and window winder mechanisms, but the bearings and gears in the drive train are a different story. High operating temperatures and voltages are key concerns. As current densities increase, so does the risk of stray currents that can pit bearings. Typical electric motor speeds, currently around 15,000 rpm, are expected to exceed 20,000 rpm in the near future. /
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