Three zone detection and distance relay co-ordination of power system protection

To secure the transmission lines against power system faults, the distance relays are mostly used. Distance relay has its own Resistance (R)–Reactance (X) characteristics. Co-ordination of different distance relays is necessary for the fast operation of circuit breaker. Various distance relays which are being tripped with respect to circuit breakers which are attached at individual buses faraway from each other. These relays will be operated with respect to the distance between the occurred fault and relay location. In this paper, detection of three zones using relay characteristics, co-ordination of distance relays and circuit breakers are shown with the faults placed at different locations of an IEEE Nine bus system using MATLAB/Simulink GUI environment. A comparison also made between the relays performance and circuit breaker tripping operation with respect to severe faults at different locations on IEEE Nine bus system

Master of Science

thesisMillions of tons of generated glass are wasted each year and being added to landfills where it takes one million years to decompose. For companies that collect and recycle used glass, contamination from brown or multicolored-glass is more difficult to recycle than the clear glass form. Even among the collected glass, the less-demanded combined colored-glass is still often dumped into landfills. One alternate way to reduce the volume of waste materials being added to landfills is by using waste glass as a supplementary cementitious material (SCM). This alternative may also help in sustainability of the concrete industry by reducing the amount of cement needed in concrete, and thus reducing the amount of carbon emissions produced due to cement production. One challenge to using this waste glass in concrete is that sand-size glass or cullet when added to concrete will cause a cracking-causing expansive reaction referred to as "alkali-silica reaction" (ASR). However, glass also contains a significant amount of silica, which is a main component in many other supplementary cementitious materials that can improve the strength and durability of concrete. It is hypothesized that a finer particle size of the waste glass will drive the reactivity of the silica from the glass to occur earlier in concrete hydration rather than at the later ages when the detrimental reaction in concrete could occur. This research focuses on determining the quantity and particle size at which waste glass powder can be effective in mortar against ASR. The probability of alkali-silica reaction is tested for mortar samples corresponding to ASTM C1567. Additional testing to verify the effect of the glass powder as a SCM on the compressive strength will be measured for mortar using ASTM C109/C109M. A separate common supplementary cementitious material called fly ash was also blended with the glass to examine whether it could provide beneficial combined effects on ASR and strength. It was found that the crushed mixed-colored glass, collected glass dust, or fly ash, when added alone or in combination, but equating to 40% replacement of cement was found to reduce the ASR expansion to the acceptable limits. However, at 10-40% waste glass dust percent replacements of cement, the 7-day compressive strength dropped by 68 to 42% compared to a mortar without any SCMs. The research also found that glass powder collected from the vacuum dust system at a crushing plant acts more effectively to reduce the effects of ASR as compared to the additionally crushed glass powder

Heap Defragmentation in Bounded Time

Knuth’s buddy system is an attractive algorithm for managing storage allocation, and it can be made to operate in real time. However, the is-sue of defragmentation for heaps that are managed by the buddy system has not been studied. In this paper, we present strong bounds on the amount of storage necessary to avoid defragmentation. We then present an algorithm for defragmenting buddy heaps and present experiments from applying that algorithm to real and syn-thetic benchmarks. Our algorithm is within a factor of two of optimal in terms of the time re-quired to defragment the heap so as to respond to a single allocation request. Our experiments show our algorithm to be much more efficient than extant defragmentation algorithms

Storage Allocation in Bounded Time

The correctness of a real-time system is very much dependent on the time at which a specific task is completed. Hence, satisfying a storage allocation request within bounded time is important. Fragmentation of the heap after repeated allocations and deallocations is a major issue for real-time systems, as most allocators depend on garbage collection for defragmentation of the heap, which might not finish in time to honor deadlines. We present the storage requirement for a defragmentation-free binary-buddy allocator. We also study a localized defragmentation algorithm to satisfy a single allocation request, within bounded time, instead of requiring defragmentation of the entire heap. We prove that the cost of the algorithm is within twice the optimal cost. Results are presented from applying the defragmentation algorithm, with different heap sizes, on various programs. The amount of storage relocated with our defragmentation algorithm is compared with other compaction algorithms. Also, the amount of storage relocated by selecting a minimally occupied block is compared with the policy of selecting a block randomly

Characterization of Pipistrellus pygmaeus Bat Virome from Sweden

Increasing amounts of data indicate that bats harbor a higher viral diversity relative to other mammalian orders, and they have been recognized as potential reservoirs for pathogenic viruses, such as the Hendra, Nipah, Marburg, and SARS-CoV viruses. Here, we present the first viral metagenomic analysis of Pipistrellus pygmaeus from Uppsala, Sweden. Total RNA was extracted from the saliva and feces of individual bats and analyzed using Illumina sequencing. The results identified sequences related to 51 different viral families, including vertebrate, invertebrate, and plant viruses. These viral families include Coronaviridae, Picornaviridae, Dicistroviridae, Astroviridae, Hepeviridae, Reoviridae, Botourmiaviridae, Lispviridae, Totiviridae, Botoumiaviridae, Parvoviridae, Retroviridae, Adenoviridae, and Partitiviridae, as well as different unclassified viruses. We further characterized three near full-length genome sequences of bat coronaviruses. A phylogenetic analysis showed that these belonged to alphacoronaviruses with the closest similarity (78–99% at the protein level) to Danish and Finnish bat coronaviruses detected in Pipistrellus and Myotis bats. In addition, the full-length and the near full-length genomes of picornavirus were characterized. These showed the closest similarity (88–94% at the protein level) to bat picornaviruses identified in Chinese bats. Altogether, the results of this study show that Swedish Pipistrellus bats harbor a great diversity of viruses, some of which are closely related to mammalian viruses. This study expands our knowledge on the bat population virome and improves our understanding of the evolution and transmission of viruses among bats and to other species

House crickets (Othroptera: Gryllidae: Acheta domesticus) reared in small-scale laboratory conditions harbour limited viral flora

Insects, such as crickets, are being used as a viable food source in many regions of the world, given their nutritional value for human and animal consumption. This study investigated the viral communities present in European house crickets and whether feed influences the composition of the crickets’ virome. The crickets were reared under environmentally controlled conditions and fed fresh red clover (fresh), red clover haylage (haylage), red clover hay (hay) or control feed. The viral metagenomic analysis of six replicates from each feed treatment showed that only a few reads were classified as viruses, mainly assigned to phages and insect-related viruses. A significant difference (PXinmoviridae, Polydnaviridae, Metaviridae, unclassified and ‘other’ viruses were also found in all the feed treatments. The results from this study may indicate that the feed for the crickets determines the richness of the viral flora of crickets, but overall, very few viral reads were identified, making it hard to draw any conclusion regarding the impact of the feed on viral richness

FDTD Analysis of Metamaterial Coated Microwave Antenna

Due to the growth in mobile wireless systems, electrically small antennas (ESAs) which are efficient and have significant bandwidth are in great demand. But these requirements are contradictory. ESAs are known to be highly capacitive in nature. As a result of this, matching a power source to the ESA requires a matching network which increases the cost in terms of manufacturing as well as real estate. In recent years a new class of materials called metamaterials has emerged. These manmade materials with their unusual constitutive parameters possess immense potential to solve the problem of size reduction. This study seeks to validate, using Finite Difference Time Domain (FDTD) technique, a new metamaterial construct to achieve the desired objectives. FDTD code is developed for a cylindrical metamaterial wrapped around a modified biological antenna. The metamaterials are modeled using a Drude constitutive parameter model to simulate frequency dispersion. Epsilon Negative (ENG) as well as Double Negative (DNG) metamaterials are taken into consideration. Results show that the ESA using a metamaterial wraparound is found to have a quality factor lower than the theoretical Chu limit. Both ENG as well as DNG metamaterials exhibit their potential. The resonant frequency of the metamaterial antenna is reduced over the classical design while the radiation pattern of the antenna remains virtually unchanged

The effect of barium titanate ceramic loading on the stress relaxation behavior of barium titanate-silicone elastomer composites

The stress relaxation behavior of barium titanate (BTO)-elastomer (Ecoflex) composites, as used in large strain sensors, is studied using the generalized Maxwell-Wiechert model. In this article, we examine the stress relaxation behavior of ceramic polymer composites by conducting stress relaxation tests on samples prepared with varying the particle loading by 0, 10, 20, 30, and 40 wt% of 100 and 200 nm BTO ceramic particles embedded in a Ecoflex silicone-based hyperelastic elastomer. The influence of BTO on the Maxwell-Wiechert model parameters was studied through the stress relaxation results. While a pristine Ecoflex silicone elastomer is predominantly a hyperelastic material, the addition of BTO made the composite behave as a visco-hyperelastic material. However, this behavior was shown to have a negligible effect on the electrical sensing performance of the large strain sensor.</p

Identification and molecular characterization of highly divergent RNA viruses in cattle, Uganda

The risk for the emergence of novel viral zoonotic diseases in animals and humans in Uganda is high given its geographical location with high biodiversity. We aimed to identify and characterize viruses in 175 blood samples from cattle selected in Uganda using molecular approaches. We identified 8 viral species belonging to 4 families (Flaviviridae, Peribunyaviridae, Reoviridae and Rhabdoviridae) and 6 genera (Hepacivirus, Pestivirus, Orthobunya-virus, Coltivirus, Dinovernavirus and Ephemerovirus). Four viruses were highly divergent and tetantively named Zikole virus (Family: Flaviviridae), Zeboroti virus (Family: Reoviridae), Zebtine virus (Family: Rhabdoviridae) and Kokolu virus (Family: Rhabdoviridae). In addition, Bovine Hepacivirus, Obodhiang virus, Aedes pseudoscutellaris reovirus and Schmallenberg virus were identified for the first time in Ugandan cattle. We report 8 viral species belonging to 4 viral families including divergent ones in the blood of cattle in Uganda. Hence, cattle may be reservoir hosts for likely emergence of novel viruses with pathogenic potential to cause zoonotic diseases in different species with serious public health implications