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"Richard Clark" wrote in message
... If that means the lore of paper processing, I was peripherally involved in trying to characterize Black Liquor (http://en.wikipedia.org/wiki/Black_liquor). Gladly I was at the extreme periphery (I am sure my sense of smell was debilitated in those years). I once had to check on an instrument I had designed that was used in our cellulose acetate butyrate esterification area. (Cellulose Acetate Butyrate is used to make Xelite and Craftsman tool handles.) Acetic anhydride and butyric acid were used for esterification. For those not familiar with the odor, think of a mixture of rancid butter, vomit, and the contents of a cat's week old litter box. Readers who watched the last season of Whale Wars on TV saw it being used against the Japanese whaling ship and its cargo. Since I was unfamiliar with the building, one of my technicians who had installed the instrument went with me. We stepped off the elevator and walked into the processing area. What had been an extremely offensive odor in the elevator suddenly hit me like a ton of bricks. I couldn't see as my eyes were tearing badly, and it hurt to breathe. My tech told me to stand still for a moment or two and things would get better. Within thirty seconds to a minute, my eyes cleared up, my sinuses opened up, and my breathing became normal again. I could no longer smell the mixed acids at all. We checked the calibration of the instrument and talked to the operators about their experiences in using it. We then left the building and walked the half mile back to the research labs. Eastman was still using dimethyl-terephthalate in their polyester production at that time, and as I waked past the DMT distillation area, I could easily smell the DMT and the Dowtherm heat transfer fluid. My technician explained that as soon as we returned to the research complex, we should drop by our group leader's office to let him know where we had been. We had just opened his door when he said that he could smell where we had been and to get the heck out of his office! Of course, we couldn't smell our strong odor at all. Fortunately my technician had warned me to wear old clothes, old shoes, and an old belt for when I came home that evening, my wife made me strip in the foyer and go stright to the shower. She washed the clothes, but the shoes and belt had to hang outside for a week. It seems that leather is particularly bad about absorbing the odor. However, returning to things RF, I also was tasked with calibrating a wood moisture meter. It used an HF RF source as part of a Z meter were Z was correlated to moisture content. The probe was a fixed ring surrounding point probes much like a Kelvin Bridge. It has always seemed paradoxical that steam is used to dry wood. We used microwave absorption to measure moisture in cellulose acetate filter tow (cigarette filters are made from this). Operators would cut off a length of tow and stuff a weighed amount in a short X-band waveguide. Attenuation was proportional to moisture. Now, finding calibrated wood was no easy task. And if we found it, we would have to first validate it (sort of a circular form of Sysphus' task). My best guess at that work set to us was that we gun-decked it. Calibration of the microwave quipment was checked by weekly sending samples to be tested by nuclear magnetic resonance. We also used samples kept in jars over certain salt solutions that maintaned a constant relative humidity in the jar. See http://www.conservationphysics.org/satslt/satsalt.php for some typical solutions. To bring a little electronics into this, the same principle is used in electrolytic capacitors where glycols, sorbitol, and various salts are used in the electrolyte to insure that it remains moist. Electrolytic capacitors are about the only electronic components that are harmed by an exceptionally dry environment. It was some years later that that task came around again when I was measuring K and Kappa as I averred. Here came the requirment for "Bone Dry" paper. Try as you might to dry paper bone dry (absolutely no water content), that as soon as it comes out of the oven it is almost back up to several percent water content (15% to 20% would be the end point). You can get close to "bone dry" in a sealed container containing zeolite molecular sieves baked at 600 C. But as soon as the container is opened, moisture rushes in from the surround air. We would use glove boxes pressurized slightly with nitrogen obtained from a liquid nitrogen source when we needed a really low humidity environment. Ironies compound in that I now live in a community where 100 years ago our cedar wood mills produced nearly a Billion shingles in a year. 73's Richard Clark, KB7QHC I always enjoyed visiting the University of Washington where Eastman was on the industrial advisory board of the Center for Process Analytical Chemistry. I never order salmon from any restaurant in the southeast after eating the wonderful, fresh-caught salmon you have there! 73, Barry WA4VZQ P.S. You mentioned black liquor from the Kraft process. I once visited the Glidden-Durkee plant in Jacksonville, FL. They originally produced turpentine from pine stumps, but now they start with tall oil extracted from black liquor. It is hard to believe that essential oils, perfume stock, and flavorings are all derived from turpentine. |
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