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Influence of Particle Geometry Assessed via Image Processing on Broken Sandstone Strength
Get PDF Particle geometry has an impact on the behavior and strength of broken rock, where particle shape characteristics affect the ability of particles to rotate or slide relative to each other. Form, angularity and texture are three independent parameters that describe the geometry of such a particle. In this paper the geometry of crushed Berea sandstone was determined through image processing, where the results showed that form and angularity indices describe the geometry characteristics of broken Berea sandstone better than the other geometry indices. A correction coefficient that has previously been introduced to predict a sieve size distribution from image processing was shown to be a function of form index for the sandstone fragments. Triaxial compression tests were performed on the broken sandstone, showing that confining pressure and void ratio have an impact on broken rock strength. Increasing confining pressure was shown to enhance the strength of broken rock, while void ratio was shown to be inversely related to broken rock strength. Void ratio can also be affected by particle geometry. Increasing particles form index increases the void ratio where particles angularity index and void ratio are inversely related
Combustion and Emission Performance of an HCCI Engine Fuelled by n-Heptane/Toluene Blends at a Low-Load Operating Condition
Get PDF Homogeneous charge compression ignition (HCCI) engine technology offers high fuel efficiency and extra low nitrogen oxide (NOx) and particulate matter (PM) emissions, which makes it a potential alternative combustion mode to conventional diesel engines. A diesel fuel is usually composed of many classes of hydrocarbons among which aromatic compounds have attracted special attention due to their specific combustion characteristics. Understanding the combustion and emission characteristics of different classes of hydrocarbons is crucial for identifying appropriate diesel fuels suitable for HCCI combustion. Toluene is a typical aromatic compound in a diesel fuel. A study of toluene content may provide implications of the effect of aromatic in a diesel fuel on HCCI combustion. In this paper, the combustion and emission performance of an HCCI engine fuelled by n-heptane/toluene blends at a low load operating condition was investigated by experiment and numerical simulation. A modified Cooperative Fuel Research (CFR) engine and a in-house-developed multi-zone model were employed. The engine was operated at the condition of engine speed of 900 rpm, relative air/fuel ratio of 3.5 and without external exhaust gas recirculation. The investigated fuel blends covered a range from pure n-heptane to 70% toluene by volume. Both experimental and numerical results showed that an increase in toluene fraction in the fuel blend retarded combustion phasing. As a result, the optimal compression ratio, at which thermal efficiency reached its maximum for a fuel blend, increased with increasing toluene fraction. The maximum thermal efficiency increased as the toluene fraction increased from 0 to 50%, but then decreased with further increasing toluene fraction to higher values. The peak pressure rise rate also increased with increasing toluene fraction at a constant combustion phasing. An increase in toluene fraction resulted in an increase in unburned hydrocarbon emissions but had little effect on NOx emissions
Matrix Transforms by Factorable Matrices
Get PDFIn the present paper an overview of existing results on matrix transforms of summability and absolute summability domains of matrix methods by factorable matrices is presented. Under the notion “multiplicative matrix” we consider a lower triangular matrix M = (mnk), where mnk = rnvk with rn,vk ϵ C
An Introduction to Architecture and Building Construction: A Starter Module for Freshers of Interior Design
Get PDF Architecture is an interdisciplinary area itself; a world of design, materials, textures, history, culture, art, technology, construction, visualisation, economics, management and so on. As it consists of many diverse knowledge-areas, the curriculum of architecture is often too loaded with different types of modules. Some modules are delivered only thematically, while some are introductory in order to prepare students to the next core modules. This paper focuses on the content development of the module of Introduction to Architecture and Building Construction, which is delivered to the fresher year of the Department of Interior Architecture and Environmental Design in their spring semestre. The module is required to complete in the four-year curriculum and is formed of two theoretical hours and two practical hours in a week. In accordance with the title as well as the structure of the module, the content was developed in two-folds. The number of the students registered for the module was 24. For the part of Introduction to Architecture, each student was assigned a well-known architect to study, which aimed to make students familiar with the names, their career path, their design approach and building characteristics, the history of movements they followed, their strands in interior design and product design. For the part of Introduction to Building Construction, it was aimed to make the students familiar with the world renowned designs as well as materials and construction technology they used. Using the series of videos explaining the design and construction process of some of the selected buildings in the lectures and the follow-up discussions formed the latter part of the module. Accordingly, the paper explains how the module content was developed, why the rationales were behind and what was aimed to achieve by this kind of structure and content
Influence of Stiffeners and Buckling Arrestors on the Behaviour of Offshore Pipelines under Bending
Get PDF On the basis of past experimental results and of a simple analytical formulation it is shown that the presence of stiffeners and buckling arrestors can substantially alter the strain and stress distribution in offshore pipelines under bending. A simple formula is provided to estimate such effects
Modified Effectiveness Model for Crossflow Packed-Bed Humidifiers
Get PDF A model for the energy effectiveness of cross-flow packed-bed humidifiers is developed and compared with experimental data. The effectiveness of the humidifier is defined as the sensible and latent heat transferred to the air to the maximum total energy available to the humidified air. Simultaneous heat and mass transfer models; available in the literature and originally developed forwent counter flow cooling towers, are utilized to develop a modified model in this paper. The main modification added to that model is a definition of the heat capacity ratio that combines the simultaneous heat and mass transfer transport in that cross-flow packed-bed humidifiers. It was found that the mixed-mixed crossflow heat exchanger effectiveness relationship developed by Kays and London agrees well with the experimental data with an average deviation of less than 10%. The mixed-unmixed correlation developed by Kays and London [12] which was recommended by Jaber and Webb is found to have larger deviation from the experimental measurements occurred at higher heat capacity ratios
A Unique View on Carbon Dioxide Emissions around the World
Get PDF Carbon dioxide (CO2) emission substantially contributes to the global warming. Its anthropogenic effects accounts for about two-third of the overall environmental pollutions. Fossil fuels (coal, petroleum and natural gas) combustion is responsible for most of the human-made CO2 release. In this article, we present and compare, in several new and unique ways, the CO2 emission in selected populated countries in all continents, which are known as highly active in fossil and/or renewable energy production / use. They include Algeria, Australia, Brazil, China, Iraq, Italy and USA. We also include the State of Illinois, USA, which is the outmost active state in fossil and renewable energy production and use, and is a pioneer state in dealing with carbon dioxide control and sequestration. By comparing the above regions with the related data of the entire world it reveals a great deal about the activities going on around the world. This may provide policymakers and environmentalists a more proper roadmap in dealing with carbon dioxide emission control policy and planning
Flower Pollination Algorithm Based PDFF Controller for a Two-Area Interconnected Thermal Power System with Gas / Diesel Units
Get PDFThis paper presents a new approach for designing a Pseudo Derivative Feed Forward (FDFF) controller for the load- frequency control of the interconnected power system comprising Thermal power system and Gas / Diesel power plants. The proposed PDFF controller is designed to improve the dynamic performance of the frequency and tie line power under a sudden load disturbance in an area with the computation of Ancillary Service Requirement Assessment Indices (ASRAI). The PDFF controller is optimized using Flower Pollination Algorithm (FPA) which is based on the quality of pollination process of flowers. The optimized PDFF controller is implemented to bring back the frequency to stable state and the net interchanges to their desired values for each control area in the shortest possible time based on the settling time and peak over shoot concept of control input deviations of each area. Simulation result reveals that the interconnected thermal power system with Gas power plant ensures a better dynamic and steady state performance than that of the system incorporated with Diesel power plant
Performance and Yield Assessment of Grid – Connected Solar Photovoltaic (PV) Dispersed Generation in Nigeria
Get PDF The problem of Renewable Dispersed Generation (RDG) and renewable resource harnessing in most cases, is not the inadequacy in resource distribution at a particular location, but rather the perpetually deprived exploitation of these resources. The existing dread for the performance of distributive generation systems that utilize renewable source for power generation has crippled generation expansion in most parts of Nigeria for several years. This study is therefore aimed at performing a practical assessment on the productivity of solar PV systems in Nigeria. In this study, five states with diverse geographical or meteorological data were selected from the cardinal regions of the country to include Sokoto State in North West, Borno State in North East, Ogun State in South West, Rivers State in South East and Abuja, the Federal Capital Territory at the center. The global horizontal radiations available from the National Aviation and Space Agency, NASA for these cities were used in simulating the performance of a 1- MW grid-tied solar PV plant using the PVsyst software. PVsyst simulation findings revealed that the performance parameters with respect to energy production favor the cities in the northern region more than the cities in the southern region with capacity factors decreasing from 20.46% in the northern region to 16.21% in the southern region for a 1- MW solar PV plant located in these regions. This was seen to reflect on the corresponding annual energy yield of similar systems sited in these locations. Also, the performance ratios of these systems given their respective reference yields were observed to be better in the southern region than the northern region of Nigeria, this could be attributed to external factors that can influence system efficiency. These factors tend to favor the systems located at the southern region better than those at the northern validating this study as a decision tool for the predictability of the performance of any Renewable Dispersed Generation, RDG systems utilizing solar energy at other regions of the country
The Prospect of Using Palm Wine As a Fluid Loss Control Agent In Water Based Drilling Mud
Get PDFThe need to advance and project the use of local materials as suitable drilling fluid additive in the oil and gas industry in Nigeria led to the research on the possible use of palm wine and potash as additives in a water base drilling mud. A comparative study of these local materials (palm wine and potash) with imported foreign materials (lignite and caustic soda) as control were used in investigating the properties of a water base drilling fluid. A laboratory investigation of the effects of temperature and aging time on the properties of water-base drilling fluid is made with Fann Model 800 High Temperature and a High Pressure (HTHP) Viscometer, according to the API recommended standard practice. The results obtained showed similarity in the drilling fluid's rheological and filtration properties; mud weight and pH values for both local and foreign additives. The result from the mud sample prepared from the palm wine and potash had apparent viscosity, plastic viscosity and yield point decreasing steadily with increase in temperature for all aging time just as shown with the control sample, while the aging effect diminishing as the aging time increases. The potash was seen to have increased the mud pH from 7.0 to 12.9 pH units. The results, shows that both palm wine and potash can be used as suitable in water base drilling mud additive