A set of experiments in porous media was performed to determine oil recovery factor during natural depletion for a heavy oil reservoir. Results on "critical or mobile" gas saturation, produced fluid characterization, residual oil saturation, production profile and effective viscosity versus pressure are presented. In order to characterize the ability of the heavy oil to trap the released gas, conventional and non conventional PVT tests were carried out. By comparing the experimental results during differential liberation tests, a gas trapping factor for the oil was obtained. It accounts for the amount of solution gas that has been thermodynamically released but does not form instantaneously a free gas cap. The so called pseudo-bubble pressure was obtained. In this work the hypothesis involved in the "Low Viscosity Model" was also tested. Introduction During the last years it has been a very large discussion about different production mechanisms to explain the production behavior observed in some heavy crude oil reservoirs specially in the Orinoco Belt in Venezuela and Lloydminster in Canada. It has been characterized by high production rates and/or high primary oil recovery, besides a good pressure maintenance. In the past, we have evaluated other drive mechanisms such as compaction, water drive and thermal process. A considerable amount of laboratory and field work has been done to evaluate compaction effects in the area of our interest. The results obtained from that study showed no evidence of subsidence or compaction, therefore it is not likely to be a major production mechanism. On the other hand, no active aquifer has been found either. According to field (well head samples) and laboratory evidence, the heavy and extra heavy Hamaca oil exhibits "foaminess" when produced under solution gas drive. P. 671

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An automated pH monitoring and controlling system for hydroponic system was developed, calibrated and validated in this study. The automated monitoring and controlling system was developed to monitor and control the pH of nutrient solution in hydroponic system. The greenhouse available at the Center for Hydroponics and Aquaponics Technology (CHAT) and locally available materials and hardware for the hydroponics and automation were used in the development of the system. These devices were designed and assembled based on the conceptual framework of the study. The pH sensor sends signal to the microcontroller which triggers the adding of acid/base solution and turning on/off of the mixer. The instruments used were calibrated prior to the performance evaluation and obtained calibration equation for the pH sensor is y = 0.91x+0.91. Validation of the automated pH monitoring and controlling system was done and the recorded maximum pH is 6.54 and minimum pH of 6.0. The lettuce planted during the validation has an average height of 14.61 cm and the average leaf count of 12 for the lettuce crops during the 4th week after planting. A total of 4.78 kg of lettuce crop was harvested with an average of 20.6 g per lettuce crop was obtained. Based on the performance evaluation and validation done on the automated pH monitoring and controlling system, it was found to be reliable. This system becomes useful in reducing labor cost and allows for real-time monitoring of pH, therefore, increasing farmer's crop productivity and income.

Depletion of fossil fuel is one of the main reasons why the bioethanol has become popular. It is a renewable energy source. In order to meet the great demand of bioethanol, it is best that the bioethanol production is from cheap raw materials. Since the golden shower fruit is not being utilized and is considered as waste material, hence, this study was conducted to make use of the large volume of the residue as feedstock to test its potential for bioethanol extraction.The main goal of this study is to obtain the most volume of bioethanol from the golden shower fruit liquid residue by the factors, days of fermentation (3, 5, and 7 days) and sugar concentration (15, 20 and 25 brix) of the liquid residue. Also, part of the study is to compute the cost of production in extracting bioethanol from the golden shower fruit. Each treatment was replicated three (3) times. The Two-Factorial Analysis of Variance (ANOVA) of the Complete Randomized Design (CRD) was used to analyze the treatments. Treatments means were compared using the Duncan's Multiple Range Test (DMRT).