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Sustainability Through Green Manufacturing Systems
Published in Anil Kumar, Jose Arturo Garza-Reyes, Syed Abdul Rehman Khan, Circular Economy for the Management of Operations, 2020
Mahender Singh Kaswan, Rajeev Rathi, Ammar Vakharia
The machining process that is performed below 123°K is called as cryogenic machining (Wang & Rajurkar, 2000; Grguraš et al., 2019). In this type of machining, a cryogenic fluid (liquid nitrogen) is used. The boiling point of the liquid nitrogen is -195°C or 77°K. The liquid nitrogen is carried in a well-insulated vacuum flask (Hong & Ding, 2001). In the past, the drawback associated with cryogenic machinic was that liquid nitrogen gets vaporized before reaching into the tool-workpiece contact area (Narayanan & Jagadeesha, 2020). To overcome this, vacuum jacketed feed lines deliver the liquid nitrogen at a slow rate, and liquid nitrogen doesn't get vaporized. The word cryo stands for frost, and genic means to produce. In this machining process, the liquid nitrogen is delivered to the cutting area through the spindle-tool very near to the cutting edge.
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Published in Michael Hehenberger, Zhi Xia, Huanming Yang, Our Animal Connection, 2020
Michael Hehenberger, Zhi Xia, Huanming Yang
The nematode is easy to culture and can be grown on agar medium and fed on E. coli. It can be stored in low temperature liquid nitrogen for several years. Adult nematodes are about 1.5 mm long and hermaphroditic. The adult organism is composed of a well-defined number of (959) somatic cells. Each cell has a clear morphological, developmental, and genetic background. The growth cycle is short, and the fertilized embryo can hatch into a free-living larva within 12 hours. The larva can mature in 40 hours. Adults can produce hundreds of offspring in about 4 days. Mutants were easily obtained in various ways, and the phenotypic characteristics were obvious. The genomic study of nematodes began in 1990, and genome sequencing and analysis were completed in 1998 and published on December 24 of that year. The C. elegans genome is about 100 Mb in size and consists of 6 chromosomes with about 20,000 coding genes. 60% of the genes are highly homologous to other eukaryotes.
Large–Scale Freezing and Thawing of Biopharmaceutical Products
Published in Kenneth E. Avis, Vincent L. Wu, Biotechnology and Biopharmaceutical Manufacturing, Processing, and Preservation, 2020
Richard Wisniewski, Vincent Wu
An alternative to mechanical refrigeration is a liquefied gas-based cooling system for the heat transfer agent recirculation loop. Liquid nitrogen is commonly used for biological freezing applications. Liquid nitrogen has a boiling point of 77.4 K (−195.6°C). Advantages of a liquefied gas system are its design simplicity, flexibility in temperature control, and its ability to achieve very low temperatures. An evaporative cryogenic heat exchanger with injection of liquid nitrogen controlled by a cryogenic metering valve can be coupled with a computer or PLC–based temperature control loop. This heat exchanger is placed in the heat transfer agent recirculating loop. A cryogenic shell-and-tube-type heat exchanger with tubes having internal fins is preferred due to its extensive heat transfer area. The heat transfer agent flows through the shell space, while the liquid nitrogen is injected into the tubes and evaporates on finned surfaces. The temperature of the heat transfer agent may be rapidly lowered to the desired low level, or a gradual temperature decrease may be programmed. The cold gas formed by evaporation of liquid nitrogen may be vented outside, passing on its way through heat recovery coils. The amount of liquid nitrogen used for cooling can be controlled so that it can follow the actual process load, which declines as freezing progresses.
Effect of novel cryogenic treatment in the corrosion behaviour, microstructure analysis and electrochemical properties of Al 6101 closed-cell foam
Published in Australian Journal of Mechanical Engineering, 2023
Zeenath Fathima Syed, Tamilarasan T.R, Milon Selvam Dennison
The working fluid of the cryogenic processor is liquid Nitrogen. The liquid Nitrogen releases a large volume of gas when it evaporates, which is highly dangerous to the human body and so it is kept in a well-insulated chamber. A vacuum insulated hose connects the cryogenic treatment chamber with the liquid Nitrogen tank. The presence of temperature sensors in the cryogenic treatment chamber detects the inside temperature. The PID temperature regulator controls the solenoid valve to direct the liquid Nitrogen stream. The liquid Nitrogen passes through the spiral heat exchanger changes into a gaseous phase and enters the channel situated at the lower part of the chamber. The blower which is at the top of the chamber plays a significant role to reduce the chamber temperature by circulating the gas inside the chamber. The process parameters are soaking time, temperature and cooling rate of the deep cryogenic treatment is constrained by the programmable temperature regulator on the cryogenic process chamber. The data acquisition system from the controller unit helps to store and record the data of the cryogenic treatment process.