No abstract

Thirty‐five polymethacrylate/chlorinated polymer blends were investigated by differential scanning calorimetry. Poly(ethyl), poly(n‐propyl), poly(n‐butyl), and poly(n‐amyl methacrylate)s were found to be miscible with poly(vinyl chloride) (PVC), chlorinated PVC, and Saran, but immiscible with a chlorinated polyethylene containing 48% chlorine. Poly(methyl) (PMMA), poly(n‐hexyl) (PHMA), and poly(n‐lauryl methacrylate)s were found to be immiscible with the same chlorinated polymers, except the PMMA/PVC, PMMA/Saran, and PHMA/Saran blends, which were miscible. A high chlorine content of the chlorinated polymer and an optimum CH2/COO ratio of the polymethacrylate are required to obtain miscibility. However, poly(methyl), poly(ethyl), poly(n‐butyl), and poly(n‐octadecyl acrylate)s were found to be immiscible with the same chlorinated polymers, except with Saran, indicating a much greater miscibility of the polymethacrylates with the chlorinated polymers as compared with the polyacrylates.

Influenza and RSV are human viruses responsible for outbreaks in hospitals, long-term care facilities and nursing homes. The present study assessed an air treatment using ozone at two relative humidity conditions (RHs) in order to reduce the infectivity of airborne influenza. Bovine pulmonary surfactant (BPS) and synthetic tracheal mucus (STM) were used as aerosols protectants to better reflect the human aerosol composition. Residual ozone concentration inside the aerosol chamber was also measured. RSV’s sensitivity resulted in testing its resistance to aerosolization and sampling processes instead of ozone exposure. The results showed that without supplement and with STM, a reduction in influenza A infectivity of four orders of magnitude was obtained with an exposure to 1.70 ± 0.19 ppm of ozone at 76% RH for 80 min. Consequently, ozone could be considered as a virucidal disinfectant for airborne influenza A. RSV did not withstand the aerosolization and sampling processes required for the use of the experimental setup. Therefore, ozone exposure could not be performed for this virus. Nonetheless, this study provides great insight for the efficacy of ozone as an air treatment for the control of nosocomial influenza A outbreaks.

No abstract

For the time being, the concrete prism test (CPT) CSA A23.2-14A or ASTM C1293 remains the most reliable test method to evaluate the effectiveness of lithium nitrate against alkali-silica reaction (ASR) in concrete; however, the extended testing period of two years has often limited its acceptance by practitioners. In its actual form, the popular accelerated mortar bar test (AMBT) CSA A23.2-25A or ASTM C1260 cannot be used to predict this effectiveness, thus it needs to be modified accordingly. Part I of this study looked at the influence of a number of parameters on the effectiveness of lithium to control expansion of mortar bars incorporating a variety of reactive aggregates from Canada and the United States. The second part of this study (Part II) compares the results obtained in modified versions of the AMBT with those from the CPT performed on the same aggregates, with the objective of proposing the best accelerated test procedure for determining the minimum amount of lithium nitrate necessary to counteract ASR expansion in concrete. The results obtained in this study have shown that the effectiveness of lithium nitrate greatly varies from one reactive aggregate to another while not being correlated with the degree of reactivity or the petrographic nature of the reactive aggregates to counteract. A safe method of predicting the effective [Li]/[Na+K] to used in concrete is proposed which uses two AMBTs, one of which involves adding lithium to both the mortar bar and the soak solution. It allows the prediction of an effective [Li]/[Na+K] for aggregates that respond relatively well to lithium. The method allows the identification of aggregates that respond particularly badly to the lithium, for which the concrete prism test is recommended for evaluating the minimum lithium dosage to use for ASR control.