Assessment of production and dispersal of inoculum ofAlternaria Macrospora in various parts of the cotton canopy
Morning and evening counts of spores ofAlternaria macrospora in a cotton (Gossypium barbadense) field were assessed for the number of spores (a) produced on the last night, (b) dispersed during the day, and (c) retained in the spore reserve on leaves. Throughout the season, 1 m2 of the field produced (P) and dispersed (D) approximately 163 x 106 and 137 x 106 spores, respectively. The 16% discrepancy between P and D values reflects experimental errors. Most spores were produced on shed leaves on the ground, fewer on leaves in the lower part of the canopy, and least on leaves in the upper canopy. The contribution to total D decreased from leaves in the lower part of the canopy, to shed leaves, and to leaves in the upper canopy. In tests with potted plants with spore-bearing lesions attached to various heights of the canopy under various conditions of weather, dispersal of spores at these heights was conditioned mainly by wind velocity, which decreased from the upper to the lower part of the canopy. In leaves close to the ground, approximately 29% of the released spores were removed by sedimentation to the ground. On any one day, the daily rate of D differed from the daily rate of P. On days in which D was higher than P, the difference was due to a reserve of spores remaining on lesions after dispersal during the previous days. In weather adverse for production of new spores, the reserve was depleted within 4 and 6 days in the top and bottom leaves, respectively, but remained relatively high in the shed leaves on the ground; a similar number of days was needed to restore the depleted reserve in sporulation-favorable weather.
Host and Environmental Influences on Sporulation In Vivo
Theoretical and practical studies of sporulation in vivo have been neglected for years. Consequently, although factors influencing sporulation are as important in disease development as those influencing infection or dispersal, they have seldom been accounted for quantitatively in the theory of epidem­ ics. This situation evolved probably from (a) the tedious experiments re­ quired, with endless counting of spores, and frustrations due to variations between replicates of similar treatments, (b) an incorrect view that the number of spores trapped over an infected field is simply related to the number of spores produced during the previous night, and (c) a misconcep­ tion that sporulation in petri dishes reflects the situation in nature. Conse­ quently, the literature contains thousands of publications on processes like infection, dispersal, and sporulation in cultures, but fewer than one hundred studies in which sporulation in vivo has been evaluated quantitatively.
Fluid to liquid membrane energy exchanger for simultaneous liquid desiccant regeneration and desalination applications–Theoretical and experimental analyses
Abstract In this paper, a thermal model developed for assessing the performance of the fluid to liquid membrane energy exchanger based liquid desiccant regenerator is presented. The model was validated with the experimental data and found accurate. Using the experimental inlet conditions reported in the literature for the structured packing chamber, the performance of the fluid to liquid membrane energy exchanger based liquid desiccant regenerator was theoretically predicted choosing water and air as working fluids and Lithium Chloride as a liquid desiccant. Further, studied the influence of inlet parameters such as working fluid and desiccant inlet temperature’s, hot liquid desiccant to cold working fluid ratio and desiccant concentration on vapour absorption rate. From this analysis, it is observed that membrane based liquid desiccant regenerator using water as a working fluid is best suitable for converting the weak desiccant into strong desiccant and for generating the pure water simultaneously (co-generation process). An experimental investigation was carried out for assessing the energy exchange process across the membrane based liquid desiccant regenerator using water as a working fluid. From the experimental analysis, it was found that desiccant temperature has a significant impact on the energy exchange process. The pressure drop across the membrane based liquid desiccant regenerator was also measured at different desiccant flow rates and concentration.