Conductometric Gas Sensors based on Nanostructured WO3 Thin Films

Nanostructured WO3 thin films have been prepared bythermal evaporation to detect hydrogen at low temperatures.The influence of heat treatment on the physical, chemical andelectronic properties of these films has been investigated. Thefilms were annealed at 400oC for 2 hours in air. AFM and TEManalysis revealed that the as-deposited WO3 film is highamorphous and made up of cluster of particles. Annealing at400oC for 2 hours in air resulted in very fine grain size of theorder of 5 nm and porous structure. GIXRD and Raman analysisrevealed that annealing improved the crystallinity of WO3 film.Gas sensors based on annealed WO3 films have shown a highresponse towards various concentrations (10-10000 ppm) H2 atan operating temperature of 150oC. The improved sensingperformance at low operating temperature is due to the optimumphysical, chemical and electronic properties achieved in the WO3film through annealing

Counting the cost: Coping with tariff increases amidst power supply shortfalls in urban households in Ethiopia

Although affordability is important, people do not need to be money poor to experience energy deprivation. This paper examines how an electricity tariff increase affects household energy consumption by situating the price change within the broader context of energy service provision in Ethiopia. We place households’ lived experience in interaction with the institutional and infrastructural dynamics that constitute the energy sector in Addis Ababa to observe how the price increase intersects with service provision. Since the tariff increase was implemented, households have changed their daily routines to control cost. Our findings show that energy consumption behaviour is also shaped by service-related inadequacies (unreliable supply and frequent power outages). However, families coping capacity (to the tariff increase and power supply shortfalls) is undermined by an energy market that is rife with information asymmetries and uncertainties. Thus, although socioeconomic factors underpin the energy insecurity households experience, inadequate supply, and diminishing confidence in service providing institutions appears to heighten their vulnerability. The paper argues that while the price change has an overall effect on consumption, its impact needs to be seen within the context of its systemic interaction with the broader energy governance and service delivery challenges

GGR1B01

Exam paper for second semester: GGR1B0

Bio-based liquid fuels as a source of renewable energy: A review

Limited availability of fossil fuels and their associated environmental impact during combustion remains the primary basis for exploring alternative energy sources such as bio-based liquid fuels. Several feedstocks have been used to produce biofuels for different applications with their own pros and cons. For instance, production of bio-fuels using human food chain raw materials such as corn, soy, peanut, and sugarcane are receiving increased criticism due to the competing demands of the same sources for human consumption as food. However, the non-food biomass in the form of agricultural wastes, municipal wastes, waste vegetable oil, and microbial sources are abundantly available that can be utilized as feedstock for production of biofuels. Because of this reason, most biofuels have been produced using the feedstocks that do not affect the food chain. Thus, in this work, the feedstocks of different generation biofuels and their potential yield and associated greenhouse gas emissions, production technologies are critically surveyed. Moreover, the application of biofuels for different purposes are analyzed and compared with their corresponding conventional fuels. The survey also points out the recent issues and challenges of biofuels with their resolution. The future research directions are suggested to sustain biofuel production

Variation for Agro-Morphological Traits among Kabuli Chickpea (Cicer arietinum L.) Genotypes

The objectives of this study were to evaluate genetic variation among kabuli chickpea genotypes and to determine the relationships among agronomic traits with seed yield. Field experiments were conducted during the long and short rain seasons of 2013 using alpha lattice design in triplicate. Data on agro-morphological traits were recorded using descriptors for chickpea and analysed using SAS 2013 and Genstat 2014. There were highly significant (p < 0.001) variations among genotypes and genotype by environment interactions for all studied traits. The top five high yielding genotypes were ICCV 05315, ICC 13461, ICCV 07313, ICC 13764 and ICCV 00302. Genotypes ranking for most agronomic traits varied across environments which indicated a crossover type of genotype by environment interactions. Evaluated genotypes were polymorphic for six qualitative traits. Seed yield ha-1 was positively and significantly (p < 0.05) correlated with biomass yield ha-1, pods plant-1, plant canopy width and secondary branches plant-1. These characters could be used for indirect selection of high yielding genotypes. The first principal component explained 57% of the total variation and was associated with days to 50% flowering and podding, plant canopy width, plant height, number of primary and secondary branches plant-1, days to 75% maturity, number of pods plant-1 and biomass yield ha-1 as positive contributors. The documented information on genetic variation and association of agronomic traits with seed yield can be exploited to devise suitable breeding strategies and chickpea germplasm conservation

Smallbelly Catshark Apristurus indicus

The Speckled Catshark (Halaelurus boesemani) is a relatively small (to 48 cm total length), data-poor catshark. It is known from a limited number of specimens collected from four locations along an ~900 km stretch of Somali coastline. It occurs on continental and insular shelves at depths of 29-91 m. Its entire distribution has been subject to at least four decades of unregulated commercial benthic trawling; shelf-occurring catsharks are very susceptible to capture in this fishing gear. The new Somali Fisheries Law bans benthic trawling, but it is suspected that past declines have already occurred given the long history of unregulated fishing across its entire range. Furthermore, enforcement of this new regulation will be a challenge. While specific data are lacking, a population size reduction of 30-50% is suspected over the past three generations (~45 years) based on actual levels of exploitation (bycatch) and the species is assessed as Vulnerable A2d. It is of concern that there have been no records since 1991, although it is acknowledged that research and monitoring have been limited in Somalia. Further investigation of this species is required to accurately define its range, biology, extent of catches in local fisheries and levels of declines. This assessment should be revisited as soon as this is available

Oman Bullhead Shark Heterodontus omanensis

The Oman Bullhead Shark (Heterodontus omanensis) is known only from central Oman and Pakistan. Although information is limited on its habitat and ecology, based on known habitats of other Heterodontus species it likely inhabits a rocky reef substrate, reducing its vulnerability to bottom trawl fisheries. However, there are trawl caught records of this species, and it is a potential bycatch of demersal line fisheries operating within its range, although no specific information is currently available. More information is required on its biology, abundance and full range, capture in fisheries and population trends. While the limited number of individuals recorded to date may suggest this species occurs in areas not fished heavily, there is currently insufficient information at assess how fisheries in the region are interacting with the species, and as such it is assessed as Data Deficient

Speckled Catshark Halaelurus boesemani

The Speckled Catshark (Halaelurus boesemani) is a relatively small (to 48 cm total length), data-poor catshark. It is known from a limited number of specimens collected from four locations along an ~900 km stretch of Somali coastline. It occurs on continental and insular shelves at depths of 29-91 m. Its entire distribution has been subject to at least four decades of unregulated commercial benthic trawling; shelf-occurring catsharks are very susceptible to capture in this fishing gear. The new Somali Fisheries Law bans benthic trawling, but it is suspected that past declines have already occurred given the long history of unregulated fishing across its entire range. Furthermore, enforcement of this new regulation will be a challenge. While specific data are lacking, a population size reduction of 30-50% is suspected over the past three generations (~45 years) based on actual levels of exploitation (bycatch) and the species is assessed as Vulnerable A2d. It is of concern that there have been no records since 1991, although it is acknowledged that research and monitoring have been limited in Somalia. Further investigation of this species is required to accurately define its range, biology, extent of catches in local fisheries and levels of declines. This assessment should be revisited as soon as this is available

Prospects of e-beam evaporated molybdenum oxide as a hole transport layer for perovskite solar cells

Perovskite solar cells have emerged as one of the most efficient and low cost technology for delivering of solar electricity due to their exceptional optical and electrical properties. Commercialization of the perovskite solar cells is, however, limited because of the higher cost and environmentally sensitive organic hole transport materials such as spiro-OMETAD and PEDOT:PSS. In this study, an empirical simulation was performed using Solar Cell Capacitance Simulator software to explore MoOx thin film as an alternative hole transport material for perovskite solar cells. In the simulation, properties of MoOx thin films deposited by electron beam evaporation technique from high purity (99.99%) MoO3 pellets at different substrate temperatures (room temperature, 100 °C and 200 °C) were used as input parameters. The films were highly transparent (>80%) and have low surface roughness (≤ 2 nm) with bandgap energy ranging between 3.75 eV to 3.45 eV. Device simulation has shown that the MoOx deposited at room temperature can work in both the regular and inverted structures of the perovskite solar cell with a promising efficiency of 18.25%. Manufacturing of the full device is planned in order to utilize the MoOx as an alternative hole transport material for improved performance, good stability and low cost of the perovskite solar cell