Problematic soil stabilization processes involve the application of binders to improve the engineering properties of the soil. This is done to change the undesirable properties of these soils to meet basic design standards. However, very little attention has been given to the reactive phase of soil stabilization. This phase is the most important in every stabilization protocol because it embodies the reactions that lead to the bonding of the dispersed particles of clayey soil. Hence, this reactive phase is reviewed. When clayey soils which make up the greatest fraction of expansive soil come in contact with moisture, they experience volume changes due to adsorbed moisture that forms films of double diffused layer on the particles. When this happens, the clayey particles disperse and float, increasing the pore spaces or voids that exist in the soil mass. Stabilizations of these soils are conducted to close the gaps between the dispersed clayey soil particles. This is achieved by mixing additives that will release calcium, aluminum, silicon, etc., in the presence of adsorbed moisture, and a hydration reaction occurs. This is followed by the displacement reaction based on the metallic order in the electrochemical series. This causes a calcination reaction, a process whereby calcium displaces the hydrogen ions of the dipole adsorbed moisture and displaces the sodium ion responsible for the swelling potential of clayey soils. These whole processes lead to a pozzolanic reaction, which finally forms calcium alumina-silica hydrate. This formation is responsible for soil stabilization.

Surge and stall are the two main types of instabilities that often occur on the compressor system of gas turbines. The effect of this instability often leads to excessive vibration due to the back pressure imposed to the system by this phenomenon. In this work, fouling was observed as the major cause of the compressor instability. A step to analyze how this phenomenon can be controlled with the continuous examination of the vibration amplitude using a computer approach led to the execution of this work. The forces resulting to vibration in the system is usually external to it. This external force is aerodynamic and the effect was modeled using force damped vibration analysis. A gas turbine plant on industrial duty for electricity generation was used to actualize this research. The data for amplitude of vibration varied between -15 and 15 mm/s while the given mass flow rate and pressure ratio were determined as falling between 6.1 to 6.8 kg/s and 9.3 to 9.6 respectively. A computer program named VICOMS written in C++ programming language was developed. The results show that the machine should not be run beyond 14.0 mm vibration amplitude in order to avoid surge, stall and other flow-induced catastrophic breakdown

Volume change in expansive soils is a problem encountered in earth work around the world. This is prominent with hydraulically bound structures or foundations subjected to prolonged moisture exposure. This behavior of clayey used as subgrade, foundation, landfill, or backfill materials causes undesirable structural functionality and failures. To prevent this happening, clayey soils are studied for possible volume change potential and degree of expansion. Consequently, the problematic soils are stabilized. In this work, the stabilization of clayey highly expansive soil classified as A-7-6 soil and highly plastic with high clay content was conducted under laboratory conditions. The treatment exercise was experimented using quicklime-activated rice husk ash (QARHA), hydrated lime-activated rice husk ash (HARHA), and calcite-activated rice husk ash (CARHA) at the rates of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%. Upon treatment with the three calcium compounds to produce three sets of treated experimental specimens, the plasticity index was observed and recorded and swelling potentials were evaluated using the plasticity index method (PIM). The results showed a consistent improvement on the properties of the treated soil with the addition of the different activated admixtures. While the utilization of CARHA and HARHA improved the clayey soil to medium expansive soil, the treated clayey soil substantially improved from highly expansive soil with a potential of 23.35% to less expansive with a final potential of 0.59% upon the addition of 10% QARHA. Finally, QARHA was adjudged as the best binding composite due to the highest rate of reduction recorded with its utilization.

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Inefficiencies of compressors and turbines resulting from insufficient pressure ratio at successive blade stages in gas turbines often lead to flow reversals. A step to statistically correlate boost pressure and vibration velocity amplitude to avoid such flow reversals therefore led to the execution of this research. A computer simulation technique was used to actualize this purpose with the operational data obtained from Delta IV unit of Ughelli power station GT 18 using VC++ programming language. Results obtained show that maximum vibration manifests on each of the bearings at a pressure ratio of 9.47 for all cases considered. These results further show a linear relationship between the data using statistical z-test.

Gas turbines play prominent role in aviation, power generation, marine, mining, petrochemicals, onshore and offshore oil and gas industries. Environmental factors result to degradation mechanics of the overall performance of the engine. Industrialist therefore face unplanned equipment and manufacturing downtime which is undesirable because it leads to economic losses and costly repairs. While condition monitoring is used to obtain early warning of impending equipment failure, optimization techniques such as water washing (online and offline) are used to bring the engine/equipment back to lime-light. In this work, several schedule visits were made to a gas turbine plant on industrial duty for electricity generation in an offshore thermal station at Ibeno, near Eket, Akwa Ibom State in Nigeria. Continuous monitoring of the aerothermodynamics and vibration data were taken for a period of twelve months on hourly basis to examine the state of health of the engine due to adverse offshore environmental factors. The diagnostic approach of vibration analysis, trend and performance monitoring were used with a model-based mixed data approach for optimizing the performance of the offshore gas turbine plant.A software code-named VANCANAL written in C ++ programming language was used to proactively monitor the gas turbine plant. The software displayed the operational (actual) values of all the parameters of the engine against their designed (reference) values. Once a set limit is exceeded, the software is capable of giving an alarm, signifying the need for maintenance.

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