PhD Theses (Agro and Rural Technology)

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    Process development for the production of briquette using agro forest waste and taro binder for rural household applications
    (2024) Narzary, Anjali
    The potential use of agro forest waste (Rice straw, Eleusine indica grass, Polyalthia longifolia leaves) for briquette production using low-power screw press machines was studied in this research. A low-cost, abundant, and novel binder, Taro (Colocasia esculenta) was used for briquetting. The briquettes obtained were tested for physical, mechanical, physio-chemical, and thermal properties. As charcoal is reported to enhance the briquette properties, so bamboo charcoal was added to the same composition of raw materials at three percentages (0, 25, and 50) % and briquetted and analyzed for fuel properties. Taguchi-Grey analysis was employed to obtain the best briquette composition based on calorific value, shatter resistance, density, water resistance, and compressive strength. The best result was obtained for the straw and 25 % charcoal and 15 % binder. Cost analysis and specific energy consumption during briquetting were also done. Specific energy consumption shows that size reduction using a chaff cutter machine consumes 87 % of the total specific energy required for briquette production. Therefore, to omit the chaff cutter machine in order to reduce the specific energy, the rice straw was carbonized for the next step before briquetting. As carbonization effectively reduces the material’s resilient properties and is effective in the reduction of pollution emissions, carbonization was the chosen pre-treatment method. The novel binder was compared with the two most widely used binders in the literature to validate its use as a binder. The result showed that the taro binder does not harm the briquette quality and is equally effective as starch and paper binder. For the last step, a low-cost manual press was fabricated at a local welding shop. The briquette obtained was compared with the same combination sample obtained using a screw press, and the best selection was obtained from Taguchi-Grey analysis. The result showed that the taro binder does not harm the briquette quality and is equally effective as starch and paper binder. A low-cost manual press was fabricated at a local welding shop to fulfill this objective. The machine was used for briquetting the best combination of straw at 15 % binder; the sample characteristics were compared with the same combination sample obtained using a screw press, and the best selection was obtained from Taguchi-Grey analysis. The samples were analyzed and compared based on physical, thermal, mechanical, and physio- chemical properties. Cost, specific energy consumption, and burning rate were also compared. The results show that as carbonization helps omit the chaff cutter from the briquetting process, the specific energy and cost of capital investment and production cost decreases. This technology is best for insitu briquette production, which will reduce the transportation cost, which is one factor that adds up to the cost of the raw materials used for briquetting.
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    Anaerobic Digestion of Terrestrial Weeds: Effect of Pre-Treatment and Co-Digestion on Biogas Production
    (2021) Saha, Biswanath
    Parthenium hysterophorus, Lantana camara and Ageratum conyzoides are considered to be among the world's top ten worst terrestrial weeds due to their reproduction potential. They can grow within a few weeks and cover entire agricultural land (Parthenium hysterophorus), forest land (Lantana camara), and native vegetation (Ageratum conyzoides). Parthenium hysterophorus, Lantana camara, and Ageratum conyzoides are difficult to manage as they can re-grow miraculously even after they are completely eradicated. The availability of Parthenium hysterophorus, Lantana camara, and Ageratum conyzoides in abundance makes attractive feedstock through anaerobic digestion. India is a fast-growing country with a population of 1.21 billion people in 2011 with a growth rate of 17.64% from 2001 to 2011 (15th Indian Census 2011) next census will be taken in 2021. The energy demand of the country is increasing rapidly due to the increase in population and industrialization. Non-renewable conventional energy sources like coal, oil, and natural gas, etc., play a crucial role in maintaining the major energy demands of the country. India depends totally on oil imports to meet energy demand. It is reported that about 200 million rupees were spent on imports to meet the two-third of energy demand in 2000. India consumes 40.34 million tons of diesel, i.e., 43.2% of total consumption in 2000-2001 and it is noted that the annual energy demand of India will increases from 0.58 to 4.02% between 2017 to 2026. According to the literature, the energy source is on the verge of extinction. The world's oil reserves are estimated to get depleted by 2050. It is expected that total oil reserves in India will only last up to 6 years. Biogas production from Parthenium hysterophorus, Lantana camara, and Ageratum conyzoides can effectively manage terrestrial weeds as well as mitigate environmental pollution caused by fossil fuels. In phase I, the BMP study of Parthenium hysterophorus, F/M ratio 2 shows the ideal combination followed by 2.5 and 1.5 respectively. In the BMP study of Lantana camara, the highest methane production was obtained from the F/M ratio of 1.5 followed by ratios 2 and 2.5 respectively. Ageratum conyzoides, BMP assay revealed that, F/M ratio 2 acquired maximum biogas production from the anaerobic digestion of A. conyzoides biomass with cow dung as the microorganism source. During phase II, the various thermal pretreatment modes (hot air oven, microwave, autoclave, and hot water bath) were applied where temperature 60 to 220˚C and time (20 to 120 mins) study were conducted. In Parthenium hysterophorus, hot air oven showed the highest efficiency in the form of soluble chemical oxygen demand (sCOD) and volatile fatty acid (VFA), for Lantana camara, and Ageratum conyzoides autoclave pretreatment was found to be more efficient, followed by hot water bath, hot air oven and microwave pretreatments. During electrohydrolysis pretreatment, voltage (10 to 60 Voltage) and time (10 to 60 mins) were conducted. In Electrohydrolysis Pretreatment, Parthenium hysterophorus at 20V for 40 mins shows the highest sCOD and VFA, and for Lantana camara and Ageratum conyzoides at 30V for 20 mins shows the highest sCOD and VFA. During phase II, the various thermal pretreatment modes (hot air oven, microwave, autoclave and hot water bath) were applied where temperature 60 to 220 ˚C and time (20 to 120 mins) study were observed. Phase III, the co-digestion of Parthenium hysterophorus was performed not only with cow dung as inoculum but also with other organic wastes (i.e., food waste). In co-digestion during the BMP assay, a mixing ratio of 1.5 (165 mL CH4 g-1 VS on the 17th day) was observed. In co-digestion (food waste) of BMP assay, mixing ratio 1.5 (211 mL CH4 g-1 VS on 14th day) for Lantana camara. In co-digestion of the BMP mixing ratio of 2 (205 mL CH4 g-1 VS on 13th day) for Ageratum conyzoides are observed to be ideal. In phase IV, the continuous scale, anaerobic digester was operated for the time span of 50 days for the best F/M ratio and pretreatment technique obtained from BMP assay. Average biogas production for untreated P. hysterophorus was 3270 mL, L. camara was 3010 mL, and for A. conyzoides was 3150 mL, for pretreated P. hysterophorus is 6454 mL; L. camara is 6219 mL, and A. conyzoides is 6982 mL, and for co digestion of P. hysterophorus is 5984 mL; L. camara is 5218 mL and for A. conyzoides is 5765 mL. In Phase V, Various bacteria were identified in microbial study. Euryarchaeota, Bacteroidetes and Proteobacteria were majorly observe in this study.
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    Assessment and alleviation of soil pollution through agro-ecotechnological interventions: role of areca nut husk biochar and vetiver grass
    (2021) Gujre, Nihal
    Several anthropogenic activities have become the preeminent sources of contamination by heavy metals (HMs), and the resultant deterioration in soil quality. Thus, the present study attempts to address the issues of soil quality degradation and its management in an environmentally compatible manner. Further, it explores agro-ecotechnological measures to improve the soil quality utilizing locally available resources. In the present study, two contaminated areas were selected in Assam to assess soil quality impact on human health and identify suitable management options. To comprehend soil quality, different physico-chemical parameters, and estimation of HMs contamination were carried out using standard protocols. Results revealed that the soil quality in both areas were degraded by increasing HM concentrations and decreased levels of nutrients. Cadmium (Cd), and chromium (Cr) are the two crucial HMs which posed severe ecological and health risk to the surrounding areas. Thus, in the quest for indigenous solutions, the present study has attempted to prepare and characterize biochar (BC) from locally available crop refuse, i.e., areca nut husk (AH). Areca nut husk biochar (AHB) prepared at a lower temperature (250° C), has intermediate stability in soil and higher soil agronomic properties, rendering it ideal for mass production as a soil amendment. The present study also explored the potential of AHB to remediate HMs contaminated soils in conjunction with vetiver grass (Chrysopogon zizanioides L.), which is well known for its various environment friendly characteristics. Results showed that AHB, along with the vetiver, has an additive effect, which includes remediation of Cd and Cr, enhanced mycorrhizal growth, and glomalin production, along with nutrient enrichment. The results demonstrated that AHB at a dose of 15 t ha-1 was most suitable for soil rejuvenation, improving soil physico-chemical, and biochemical properties.
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    Formulation and Characterization of Leafy and Non-Leafy Vegetables Based Mix Soup Formulations
    (2021) Mondal, Imdadul Hoque
    To encourage translational and value added product development of endemic and underutilized horticultural produces, current Ph.D. thesis is targets upon a robust experimental and design methodology to formulate and characterize leafy and non-leafy vegetable based mix soup recipes with high nutritional content in terms of proximate, vitamin C and antioxidant activity characteristics. The targeted leafy and non-leafy vegetables in the thesis includes Kolmou (Ipomoea aquatica Forssk.), Pui (Basella alba) and Jatialao sak (Lagenaria siceraria leaves) and Kolphul (Musa balbisiana Colla blossom), Kaskal (Musa splendida), green Komora (Benincasa hispida) and Posola (Musa balbisiana Colla pseudostem), respectively. After ensuring a critical discussion with respect to available prior art, lacunae, objectives and thesis organization in Chapter 1, the adopted overall research methodology has been presented in Chapter 2 of the thesis. Thereafter, Chapter 3 addresses the comparative efficacy of tray and oven drying processes towards the chosen leafy vegetables in terms of the nutritional characteristics of the dried vegetable samples. Chapters 4 and 5 targets upon the optimization of process-product characteristics of the chosen leafy and non-leafy vegetables, respectively. Both trial and error and statistical design approaches have been addressed in these chapters. Thereafter, Chapters 6 and 7 address the findings associated to the optimal leafy and non-leafy vegetable mix constitution based on nutritional optimization and sensory analysis. Finally, Chapter 8 summarizes the subjective and objective conclusions of the Ph.D. thesis and possible directions for future research.
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    S & T Intervention in Bell Metal Product Manufacturing: Process Improvisation, Product Diversification and Drugery Free Workstation Design
    (2022) Sarkar, Pranay Kumar
    The bell metal industry worldwide enjoys heritage estate. However, field survey and literature review shows the industry is presently encompassed with several difficulties, such as age-old traditional production techniques, limited range of products, lack of modernization in terms of workstation, tools and equipments design, etc. The average annual transactions of the Sarthebari bell metal cluster have decreased from Rs. 11 million in 2017–18 to Rs. 7.5 million in 2019–20 and hence the workers are experiencing a very tough time. Moreover, the young artisans have started to leave the occupations due to the presence of a very high level of drudgeries with the current production units and hence, the bell metal industry is facing the manpower scarcity problem. To encourage the young entrepreneurs, this Ph.D. thesis devotes towards the drudgery reduction from the bell metal products manufacturing industries through S&T interventions. Firstly, the thesis addressed the mechanical properties of bell metal processed in different conditions for improvisation of the present production process. Thereby, oil quenching has been evaluated to be superior for products that required finishing work at room temperature against the present practice of the water quenching process. Another aspect of this study is creating a database on the mechanical properties of bell metal processed in different conditions to help the engineers on selecting the exact processing conditions for the specific applications. Thereafter, this thesis invented that the bell metal can be joined through TIG welding process and then different sets of TIG welding parameter has been proposed based on Pareto optimal solutions for various applications. The outcome of this study will open new markets for the industry by allowing the production of diversified welded bell metal products. Further, the thesis advocated for statistically determining the level of drudgeries associated with the present bell metal production process.. Eventually, a user-centric ergonomically correct workstation has been proposed along with the dimensions of few regularly used tools and equipments to reduce the level of drudgeries experienced by the bell metal artisans. Finally, the amount of copper leached in the drinking water from the bell metal utensils has been measured to prove the existing perceptions of the health benefits of using the bell metal utensils. Overall from the thesis work, it has been expected that due to reduced drudgery and increased efficiency of the designed workstation, on implementation, the young artisans who began to leave the trade will start to return to the occupation and hence the manpower scarcity problem will be resolved. Moreover, due to the opening of new markets and improved production process, the income level of artisans will increase and hence, the standard of living of millions of people engaged with the industry will improve.
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    Study of a concurrent development- dissemination model for appropriate technology: Case of improvised Chaak for pottery industry
    (2020) Bhattacharjya, Bibhuti Ranjan
    In the present research endeavour, an attempt is made to redesign traditional Pottery wheel with consideration of ergonomic principle and the local people’s anthropometric data. Target users’ anthropometric data are the prime requirement for successful design intervention. However, paucity of anthropometric data of target users from Assam, India, is the major concern. To bridge the void, an attempt is made here to gather and to analyse the anthropometric data of five ethnic groups (Boro, Garo, Hira, Karbi, and Rabha) from Assam, India. Seventy-two anthropometric body dimensions, including the age and body weight of 453 people from different districts of Assam, India, are summarized. The variation in anthropometric data considering gender and ethnic diversity is also examined, and significant differences are observed in relation to gender and ethnicity. T-tests are carried out to verify the statistical significance of the variations in anthropometric dimensions across ethnic diversity within the same gender. Factor analysis and regression modelling are also done as part of the study. Further, the collected data are used to redesign the traditional Chaak i.e. traditional pottery wheel (TPW) and, cater to their comfort with added safety. Treadle mechanism is skillfully adapted in the machine. A four-bar crank rocker mechanism is constructed to obtain the necessary motion. In deciding the different parameters of the four-bar planner crank rocker mechanism, anthropometric data of the target users are considered. A full-scale model of the Improvised Pottery Chaak (IPC) is fabricated and field tested. The field-testing results clearly demonstrate that the design intervention is successful in reducing the health discomfort and energy expenditure besides reduction of increased heart rate. Male artisans' average productivity is found to be almost 1.7 times higher in the case of IPC than that of the TPW. Similarly, female artisans’ average productivity is found to be almost 1.8 times higher in the case of IPC than that of the TPW. The product along with its manufacturing process is successfully transferred to three rural micro-enterprises. Manufacturing process details and maintenance-related issues are demonstrated to them. In the absence of a structured approach and institutionalized intervention, such technology design and innovation efforts do not cater to the needs of the marginalized people living at the bottom of the pyramid (BoP). Hence, in this study, based on the experiences gathered from technology transfer of IPC, an effort is made to study technology transfer framework involving rural micro-enterprises.