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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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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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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How I Do Work-Life Integration

How I Do Work-Life Integration

collaborations, processes, public perceptions, Uncategorized
People used to talk about work-life balance as if they were two separate things. Now they talk about work-life integration, but what they mean is finding ways to infiltrate every hour of every day with this work that is not really your life. I choose to do things differently. Seems to me that if left to our own devices, people would just spend all day doing what gives us pleasure. Some of that would involve doing things that help other people or make them happy and some would be just for us. Centuries ago, people discovered that different people like doing different things. If you take on a task that I don't enjoy, and I take on a task that you don't enjoy, that leaves both of us more time…
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These iron curtains are very, very sheer.

These iron curtains are very, very sheer.

Materials Science, processes, Uncategorized
Recently, a group of researchers in Dresden, Germany found a way to make one-atom-thick sheets of iron. It wasn't what they had set out to do, but they were alert enough to see this as the intriguing discovery it was rather than an annoying byproduct to be cleaned up. Thin metal films are used as coatings or wrappings (aluminum foil, for example), components in optical and laboratory instruments, and as chemical sensors and catalysts. For a lot of high-tech applications, including high-density recording media and electronic devices, the thinner the film, the better. The ultimate thin film would be a sheet one atom thick — a monolayer. Carbon monolayers, known as graphene, have been around for a few years, and researchers have been busy exploring the unusual properties of these…
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Can We Talk?

communications, explorations, processes
(Reprinted from Flying Lessons: verbal-aviation.blogspot.com) My year off is officially over. I'm still at home, but I'm actively looking for work. Maybe that will be a job in the conventional sense of the word, or maybe it will be a more creative way to bring in income. I'm not sure. I've tried telling myself that I ought to be checking the job ads more assertively, mailing brochures to potential clients, making cold calls and all. But it just doesn't feel right. I have chastised myself, telling myself to just get over my inertia and start the wheels moving again. Don't be such an introvert, I say. Which is kind of like telling myself to stop having such blue eyes or stop being so short. I have found a much better…
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Signal to Noise Ratios

Signal to Noise Ratios

collaborations, explorations, processes
Back to the science metaphors today. I got to thinking about how radically I have emptied out my schedule this year, and how it's helping me pay attention to things too long ignored. Improving the signal-to-noise ratio, as it were. Right after grad school, I spent three years as a postdoc at Los Alamos National Lab. I was studying the way that surfaces influence the structure of thin coatings, to see if you could set up a surface that could direct a thin film to form with the properties you wanted. In order to pick up any kind of a signal at all on my instruments, I had to start out with substrate materials that had a whole lot of surface area, just to have enough of the thin film…
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