Agricultural and Biosystems Engineering

... Peter Mulamba, Assistant Lectuerer, Department of Agricultural Engineering, Makerere University, PO Box 7062, Kampala, Uganda, mulambap@yahoo.com ... Turinawe and Mulamba (1999) carried out a study on microirrigation scheduling for cabbage at MUARIK based on ...

Biomaterials involving life, could be bio-derived or bio-inspired and have properties and characteristics that are quite complex to be adequately synthesized and analyzed by deterministic methods. Probabilistic modeling tools provide necessary insights and understanding of mechanisms and processes induced and/or integrated in them for purposes of applications in biology, medicine and engineering. The hypothetical additive and synergistic effects potentiated by the common cellular targeting of the microtubule stabilization are eroded depending on the heat delivery temperature, Paclitaxel nanoparticles (Taxol) concentration and sequence of application. The purpose of the study was to provide better predictive understanding of the effects of hyperthermia (41o to 45o C), Paclitaxel nanoparticles (Taxol) and their synergistic combination on the growth and shrinkage of MDA-MB-231 cells. As an application of the study, characterization of the temperature pattern distribution from the recently fabricated implantable hyperthermia device was achieved in a monolayer of these cells. Overall, the more nonlinear exponentiated polynomial quotient response Z (QRZ)-models with degree (K+1) contextually modeled the phenomenon of hyperthermia (physically illustrated by use of Isohypethermals) and the live cell count response to Taxol in both early and late cell generations. The mixed log-normal and exponential multiparameter QRZ-model effectively predicted the peripheral temperature developed by the newly fabricated implantable hyperthermia Microdevice. The model predictive power and the unit change effects of the drug concentration and exposure times based on the developed QRZ-model were best characterized using chemographs. The study provided improved understanding of the effect of combined hyperthermia (41o to 45o C) and Paclitaxel nanoparticles from a quantitative point of view. Temperatures below 43 oC did not adequately inhibit growth of the most invasive MDA-MB-231 cell line. Contrastingly, growth of cancer cells was completely inhibited by temperatures at and above 43 oC. It has been demonstrated for the first time by use of Isochemotherapy curves the existence of the minimum critical hyperthermic temperature (MCHT) of 43oC. This finding gives the potential temperature for the synergistic outcome of simultaneous application of both hyperthermia and Taxol in treatment of breast cancer. Depending on the temperature regime for the combinational therapy either below 43oC or at and above 43oC, drug diffusion or heat transfer and diffusion becomes dominant cell-killing agent, respectively.

This study was conducted for a period of 4 weeks to monitor and evaluate the process of bio-stimulation and
natural recovery rates in terms of bacteria and fungi communities to diesel contaminated soils. In this study, laboratory
experiments were conducted to measure pH, moisture content, Potassium (K), Phosphorous (P), Organic Nitrogen (ON),
Organic Carbon (OC), Organic Matter (OM), fungi and bacteria cells before and after soils were intentionally
contaminated with diesel. The results of this study showed that treatment level, K, P and pH have a positive effect on the
number of bacterial cells whereas moisture content, sand and clay particles impact negatively. A correlation coefficient of
R2 = -0.93 was obtained between time and OC, OM, ON while OC, OM, ON and bacteria showed an R2 = -0.58. Three
conclusions can be drawn based on this study. One, by week 4, bacterial cells counts had doubled. Two, by week 4,
bacterial counts numerically outnumbered fungal cells. Three, the increase in both bacterial and fungal cells was
accompanied with a decrease in OM, OC and ON. This means that both bacterial and fungal cells had adapted by week 4.

The purpose of this study was to investigate the performance of a natural convection solar tunnel fruit dryer and to determine an appropriate thin layer model to predict the drying. The dryer comprised of three major units: a solar collector unit, a drying unit and a bare flat-plate chimney. To investigate its performance, six sets of drying experiments with mango as the product, were carried out at the University of Zambia, Department of Agricultural Engineering under natural conditions and the following parameters were recorded: the drying time, air temperature, relative humidity, solar irradiance and air velocity. The solar irradiance varied between 470 and 1070 W m-2 , while air temperature of up to 70 °C was recorded at the collector unit. Ambient relative humidity varied between 11.95 and 29.67 % and was lowered by over 50 % in the dryer. With relatively low air velocities, the buoyant pressure ranged from 0.1530 to 0.3016 N m-2. Under these conditions, mango with an initial moisture content of 80 % (w.b.) was dried to between 13 and 14 % (w.b.) in 11 hours. To find an appropriate thin layer model, the moisture content results were transformed to moisture ratio and fitted into 12 common thin layer models in literature using the MatlabR2011b curve fitting tool. The best model was determined based on three statistical parameters: R 2 , SSE and RMSE. Midilli-Kucuk model was found to be the best model with R 2 , SSE and RMSE of 0.9959, 0.004634, and 0.01758 respectively.

Conventional water treatment is constrained by factors such as variation in raw water quality, inefficient coagulation, use of inappropriate sand for filtration, and poor backwashing process among others. The objective of this study was to find out the impact of daily and seasonal variation of raw water quality on conventional water treatment through the jar testing process. Short filter run times as low as 12 h were experienced at Gaba complex requiring emergency backwashing. The short filter run times were envisaged to be resulting from the inability of the coagulation process to cope with the varying water quality. Generally, the pH of the water samples showed no significant (p>0.05) difference in both the dry and wet period. The water turbidity and colour were significantly (p<0.05) higher in the dry period compared to the wet period. The optimum alum dose (60 to 70 mg L-1) for each jar test showed up to 92% turbidity removal and complete colour removal. Variation in the raw water quality both daily and seasonally did not significantly (p>0.05) affect the amount of coagulant required for optimal water treatment. The short filter run times therefore, could be due to other factors to be investigated.