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Cleaning Validation—Lifecycle Approach
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Properties of the cleaning agent must be understood. The cleaning agent may be a simple commodity chemical such as sodium hydroxide, may be a proprietary formulated mixture with multiple components, or may be a nonaqueous solvent. Proprietary cleaning agents may include ingredients such as surfactants, chelating agents, dispersants, corrosion inhibitors, enzymes, and other ingredients. The pH of the cleaning agent mixture may be acidic, basic, or neutral. The effects of the cleaning agent on the residue must be understood for multiple reasons. The effect of the cleaning agent on the residue is obviously relevant to the efficacy of the cleaning process. For example, an alkaline cleaning agent that dissolves the residue is likely to more effectively clean equipment than one in which residue is not soluble. Judgments regarding worst-case residue in a cleaning matrix are partly based on residue solubility, which in turn may be affected by solvent pH. An example of pH effects on cleaning is described later in this chapter. Residue composition must be known to develop an appropriate analytical method for cleaning validation. Analytical methods may be specific or nonspecific depending on the residue composition. Residual cleaning agent must also be removed from equipment as part of the cleaning process.
Effect of face sheet on the flexural and tensile characteristics in GLARE laminates
Published in Australian Journal of Mechanical Engineering, 2023
Harish Kumar M, N. Rajesh Mathivanan
The fabrication and sample preparation procedure is adopted from the available literature (Zheng et al. 2015; Fiore et al. 2013; Xu et al. 2016) and modified as per the research facility available at the research institution. The commercially available aluminium alloy Al-2024 was procured in the form of sheets of 0.2-mm thickness. Prior to laminate preparation, the sheets were subjected to a surface treatment procedure so that the bonding between the intermediate layers can be enhanced. Out of various surface treatment methods, anodisation is selected as a surface treatment method, since it is readily available at the researcher’s laboratory. Diluted phosphoric acid with a ratio of 1:15 in distiled water is used for anodisation purposes. The surface treatment is carried out at room temperature (28°C) for 30 minutes and with the application of 12-V potential difference across the plates. After this, the sheets were thoroughly washed with water and pat dried to remove any moisture content from it. Acetone is used as a cleaning agent to clean the dirt or any other material still adhered to the aluminium sheet surface. A similar procedure is adopted to prepare the aluminium sheets of a thickness of 0.3 mm and 0.4 mm.
Pulmonary functions and associated risk factors among school teachers in a selected Nigerian population
Published in International Journal of Occupational Safety and Ergonomics, 2022
Chidiebele Petronilla Ojukwu, Precious Chinecherem Ogualaji, Stephen Sunday Ede, Rita Nkechi Ativie, Chigozie Okwudili Obaseki, Adaora Justina Okemuo, Franklin Onyedinma Irem
A self-administered questionnaire adapted from a validated asthma questionnaire [20] was used to collect subjective data. The questionnaire was structured with four sections. Section A contained questions on socio-demographic characteristics of the teachers (age, gender, body mass index (BMI), cigarette smoking, alcohol consumption, practice of physical exercise, place of residence). Some of the questions (cigarette smoking, alcohol consumption, practice of physical exercise) were dichotomized on ‘yes’ versus ‘no’ response. Section B comprised questions on occupational characteristics of the teachers (duration of employment, type of school, school level taught, type of teaching boards, working hours per day, whether there was previous occupation). Section C comprised five questions on occupational exposures of the teachers (chalk dust, disinfectant, cleaning agent, gases/vapor, others). Lastly, section D contained questions on residential characteristics of the teachers (congested living area, use of gas, use of firewood, use of cooking kerosene, use of air conditioner, presence of drapes, presence of carpets, use of pest control). These questions were dichotomized on ‘yes’ versus ‘no’ response. The asthma questionnaire elicits questions on lifestyle exposure and practice that could affect normal pulmonary values.
Towards a better preservation of current and future outdoor architectural heritage; maximum suppression of discolouration in anodized and non-anodized titanium sheets
Published in Environmental Technology Reviews, 2020
Maryam Mokhtarifar, MariaPia Pedeferri, Maria Vittoria Diamanti
To overcome the challenges mentioned above, researchers developed a removal cleaning agent by combining water-soluble inorganic acid salt and organic acid or organic acid salt with surfactants and some other additives which not only helped for minimizing the impairment of the outer appearance of the base layers, but also helped inhibiting discolouration after removal [41]. For instance, inorganic acids mainly inorganic fluorine compounds react with discoloured section and so remove discoloured parts on titanium. Organic acids, on the other hand, convert calcium included in the titanium oxide layer into calcium salts and dissolve or disperse them into the cleaning agent. Apart from organic/inorganic acids, using surfactants leads to improve the permeability and wettability of the cleaning agent in the discoloured sections and maximizing the cleaning effect as a result. Moreover, hydrophilic oxygen containing hydrocarbon solvent such as ethylene glycol can control the evaporation of water and adjust the drying property after the coating of the cleaning agent. Furthermore, additives such as thickeners, discolouration inhibitors and polishing particles (with 1–100 size) can inhibit from discolouration by adjustment of viscosity and exhibiting an effect against scattering and dripping, inhibiting the occurrence of rediscolouration and increasing the effectiveness for the removal of titanium oxide layer, respectively. Table 1 summarizes the main chemical components and additives of their invention in addition to the function of each component.