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Gas Filtration Applications in the Pharmaceutical Industry
Published in Maik W. Jornitz, Filtration and Purification in the Biopharmaceutical Industry, 2019
The purpose of a vent filter on a sterile fermentation/bioreactor tank is twofold: to prevent contamination of the tank and to provide containment of the material inside the tank. Prevention of contamination in the tank is desirable for processes that involve long fermentation cycles or require a sensitive fermentation medium (e.g., tissue culture medium). Genetic engineering techniques, as well as fermentation of pathogenic organisms (such as organisms used for the manufacture of vaccines), have made it necessary to protect the environment and prevent the escape of microorganisms from the fermentation tank. The exhaust filtration system for a recombinant or mammalian cell fermenter/bioreactor must yield sterile and often also virus-free gas to the environment and provide a reliable barrier to prevent ingression of contaminants. Additionally, it must be in-situ steam sterilizable and should typically have a clean differential pressure less than 0.07 bard (1 psid).
Monitoring and detection of damage in cement composite under sulphate attack
Published in Jaap Bakker, Dan M. Frangopol, Klaas van Breugel, Life-Cycle of Engineering Systems, 2017
Sumedha Moharana, Bhavini Garg
This paper represents the monitoring of sulphate induced damages in cement composite in realistic manner. The realistic approach has been developed by setting up an accelerated sulphur-rich environment. The accelerated testing adopted here offers a realistic method of predicting the deterioration of concrete under sulphate attack. The ingression of sulphates over cement compound has been monitored through Half-cell potential method. Mass variation has been noted for all the sulphate exposed samples. The chemical damage on cement composite at the microstructural level has been studied through powder X-Ray diffraction of the samples.
Solar Power Fields
Published in Anco S. Blazev, Solar Technologies for the 21st Century, 2021
Major drivers of this process are: Negative cell polarity vs. groundMoisture ingressionHigh operation temperatureNa (sodium) content in glass
Bio-remediation of cracks – a novel technique to self-heal cracks in the concrete
Published in European Journal of Environmental and Civil Engineering, 2023
The experimental investigation on the use of microbes involves evaluating the concrete’s strength, durability and self-healing characteristics. For this, two bacterial species, namely B. subtilis and E. coli of 101, 103 and 105 cells/ml, were cultured, and the concrete properties were studied at suitable ages. The optimal cell concentration of both bacterial species was found to be 105 cells/ml. The strength and durability properties of the microbial concrete improve with an increase in the cell concentration of the bacteria. The direct dependence of various parameters, such as strength, ingression of acids and sulphates and cell concentration were well defined with the regression analysis. Figure 13 shows the correlation of water absorption with strength, acid and sulphate ingression. A higher correlation factor of 0.99, 0.985 and 0.986 was observed with water absorption and strength, acids and sulphates. It is observed that the pore volume of concrete is directly dependent on the strength and durability properties of the bacterial concrete. An increase in the cell concentration decreases the water absorption of the concrete. As the water absorption of the concrete decreases, the strength of the concrete increases, rate of ingression of acids and sulphates decreases. The decrease in the water absorption is due to the precipitation of CaCO3 by microbes. However, the performance criteria of microbes on the mechanical properties indicate that B. subtilis show improved properties compared to E. coli at all curing ages. This was evident through the SEM images as B. subtilis shows higher and denser calcite precipitation than E. coli. The investigation on the effect of bacterial cell concentration was concluded till 105 cells/ml as many literatures (Jena et al., 2020; Mondal & Aparna, 2018; Nain et al., 2019; Pachaivannan et al. 2020) indicate the optimum level of replacement of B. subtilis as 105 cells/ml irrespective of the culture media. The remediation of cracks was evident with the precipitation of CaCO3 that fills the cracked surface on the concrete.