Designing and Development of a Photobioreactor for Optimizing the Growth of Micro Algae and Studying Its Growth Parameters

This thesis presents the estimated value of materials required to grow 1g of biomass and the analysis of the light intensity with respect to flow path and flow rate. This thesis aims to design the sparger for a flat plate Photobioreactor, study the flow patterns at different flow rate of air flow and check the performance of flat plate PBR by growing the cyanobacteria. The estimated value to produce 1g of biomass (C44.6H7O25N7.68P0.9S0.3) was 0.099g of N, 0.493g of C, 0.160 g of Na, 0.026 g of P, 0.009 g of S, and 0.007 g of Mg. The energy required to fix carbon atoms in 1 mole of biomass was found to be 78,584,302 J. The net energy loss of the system was calculated by subtracting net enthalpy of reactants from net enthalpy of product which was found to be -3800.724 KJ. Light plays a great role in the performance of PBR. The equation was also developed to find the relationship of light intensity with path length and gas flow rate. The sparger plays a major role in deciding the performance of the PBR. It is one of the means for mixing so that the gas can pass though the growth medium by bubble which is created by the passing the gas through the holes of the sparger. Mixing helps in proper distribution of nutrients to the medium in Photobioreactor (PBR), maintaining the uniform temperature. The sparger was designed using a SPARGER software built on a Java platform to simulate the flow and pressure distribution along its length. Sparger diameter of 0.5 inch was designed with a hole diameter of 1/32 inch and spacing of 4.04 cm. The simulation result showed non-uniformity of less than 5% and the percentage of airremaining after the last hole less than 1%. With the designed sparger the flow patterns of bubbles were observed in 160L water in three different conditions. The first one was using the different number of sparger pipes ranging from 1 to 4. The second one is using the different gas flow rate and the third one is observing the flow patterns at different height. Larger number of sparger pipes shows the better mixing, 10LPM flow rate was observed to have a uniform bubble distribution and at the higher depth the flow was observed to be air lift. The designed sparger for the PBR system was used in a PBR to grow cyanobacteria. Cyanobacteria was grown on BG-11 media and the highest concentration of biomass was found on 13th day with a value of 928 mg/L. The physical parameters like Oxidation Reduction Potential (ORP), Dissolved Oxygen (DO), pH and temperature were studied. The range of ORP, DO, pH and temperature were found to be 169.76 to 327.67 mV, 8.68 to 8.20 mg/L, 6.15 to 8.09 and, 26.81°C to 30.91°C respectively. The observed results were compared to the small reactor results

Machine Learning Based Autism Detection Using Brain Imaging

Autism Spectrum Disorder (ASD) is a group of heterogeneous developmental disabilities that manifest in early childhood. Currently, ASD is primarily diagnosed by assessing the behavioral and intellectual abilities of a child. This behavioral diagnosis can be subjective, time consuming, inconclusive, does not provide insight on the underlying etiology, and is not suitable for early detection. Diagnosis based on brain magnetic resonance imaging (MRI)—a widely used non- invasive tool—can be objective, can help understand the brain alterations in ASD, and can be suitable for early diagnosis. However, the brain morphological findings in ASD from MRI studies have been inconsistent. Moreover, there has been limited success in machine learning based ASD detection using MRI derived brain features. In this thesis, we begin by demonstrating that the low success in ASD detection and the inconsistent findings are likely attributable to the heterogeneity of brain alterations in ASD. We then show that ASD detection can be significantly improved by mitigating the heterogeneity with the help of behavioral and demographics information. Here we demonstrate that finding brain markers in well-defined sub-groups of ASD is easier and more insightful than identifying markers across the whole spectrum. Finally, our study focused on brain MRI of a pediatric cohort (3 to 4 years) and achieved a high classification success (AUC of 95%). Results of this study indicate three main alterations in early ASD brains: 1) abnormally large ventricles, 2) highly folded cortices, and 3) low image intensity in white matter regions suggesting myelination deficits indicative of decreased structural connectivity. Results of this thesis demonstrate that the meaningful brain markers of ASD can be extracted by applying machine learning techniques on brain MRI data. This data-driven technique can be a powerful tool for early detection and understanding brain anatomical underpinnings of ASD

Benefit Estimation of Water Quality Improvements in Bagmati River Using Choice Modeling

Environmental Economics and Policy,

Human immunodeficiency virus, acquired immunodeficiency syndrome (HIV/AIDS)：awareness and attitude among school teachers

Introduction: Awareness and attitude regarding human immunodeficiency virus and acquired immunodeficiency syndrome (HIV/AIDS) can play a crucial role in providing health education and prevention of HIV/AIDS. This study aims to find out awareness and attitude regarding HIV/AIDS amongst secondary level school teacher. Method: During 3-months period in 2018, secondary level school teachers in Lalitpur district in Kathmandu valley, Nepal, were randomly selected by lottery to find out their awareness and attitude regarding HIV/AIDS. A self-administered structured questionnairesand a five-points Likert attitude scale was used to collect data. Data was analysed with SPSS version 16. Result: Among 116 school teachers included in the study, 94 (81%) had adequate level of awareness on HIV/AIDS, 115(99.1%) were aware about sexual transmission of HIV, 112 (96.6%) about not being transmitted by eating drinking from same utensils and 113 (97.4%) knew commercial sex workers as high-risk group. Overall, 106 (91.4%) had favourable attitude regarding HIV/AIDS. There was no significant correlation between awareness and attitude. Conclusion: The HIV/AIDS awareness among secondary level school teachers was adequate, their attitude was favorable. There was no association between awareness and attitude. Keyword: attitude, awareness, HIV/AIDS, school teacher

Demand for Environmental Quality: Evidence on Drinking Waterfrom Kathmandu, Nepal

This paper examines the demand for environmental quality - clean drinking water in particular - in Kathmandu, Nepal. Water supply is inadequate, unreliable, low quality and not directly potable. Residents engage in several strategies to cope with unreliable and low quality water supplies. Some of the major strategies are: hauling, storing, boiling and filtering. A Report on the Water Survey of Kathmandu Valley 2005 suggested that over 45 per cent of households filter water to make it potable, while about 39 per cent of households boil water. Use of Uro Guard and the Solar Disinfection System (SODIS) are other purification methods. To date, there has been little empirical analysis of such purification behaviors. This paper investigates these purification behaviors and the factors influencing them. We consider different types of treatments as demand for environmental quality. Using the Water Survey of Kathmandu, we estimate the effect of education level of household head, exposure to the media, gender, caste, ethnicity and opinion of water quality on drinking water purification. Treatment costs are calculated from respondents’ answers on treatment types, market price and value of time. We also estimate expected willingness to pay for environmental quality from the average cost for different types of treatment. Moreover, the impact of education level of household head, exposure to media, gender, caste, and ethnicity on willingness to pay is also evaluated

Coping with unreliable water supplies and willingness to pay for improved water supplies in Kathmandu

This paper estimates both the households’ costs of coping with the problem of unreliable public water supplies and their willingness to pay (WTP) for improved water supplies in Kathmandu valley. Coping costs are calculated from respondents’ answers on averting behavior, market price and value of time. The willingness to pay for improved water supply is calculated using stated preference method, which is then compared with the value obtained from revealed preference method. This paper also discusses the effects of a household’s socio-economic characteristics on its coping costs and WTP for improved water supply