Strength and hydrodynamic performance of a multihull vessel

PhD ThesisThe use of catamarans as an alternative to more conventional monohull high speed vessels for transport, naval and offshore applications is on the increase. This uprising trend is a direct consequence of the global demand for commercially and militarily efficient vessels that offer high speed, potential for improved Sea-keeping at speed, relatively low hydrodynamic resistance in waves and a more useable deck area. The configuration and hull geometry of catamarans are very critical to achieve improved sea-keeping and other hydrodynamic performances. The Round Bilge hull form is one of the most prominent hull geometries in use for the design of displacement-type multi-hull vessels. An alternative hullform series to the Round Bilge, catamarans, named the Deep-V Catamaran series (DVC), has been developed recently at Newcastle University. Early studies on the DVC concept based on this series indicate that the hull form may have better resistance performance than the Round Bilge. However, other important characteristics of this concept such as the motions and wave-induced load response characteristics are still unknown. There is also a lack of understanding of the general hydrodynamic characteristics of the DVC concept in comparison to the Round Bilge hull form. This study contributes to the understanding of the motions and wave induced load response characteristics of the DVC concept. It is also intended to advance the structural design methodology of the DVC concept and its subsequent application as better alternative to the Round Bilge hull form. The study involved the experimental and numerical investigations of the motions and wave-induced load response characteristics of the DVC concept by using a prototype model of “The Princess Royal” which is the current research vessel of Newcastle University. The experimental studies involved the motions and wave-induced response measurements in regular waves at both zero and forward speed conditions. The results obtained were validated using alternative potential flow-based numerical codes in frequency domain. The benchmark study indicates that the numerical codes are capable of producing acceptable results. A comparative study using a representative model of the Round Bilge hull form with the DVC model was conducted in order to establish a direct basis for the comparison of the motion and hydrodynamic load performances. The results obtained from this comparison reveal that the DVC may have better sea-keeping characteristics and is less sensitive to wave loads than the Round Bilge hull concept in critical heading conditions. A further comparison of the experimentally validated numerical predicted loads with those obtained using the International Association of Classification Societies (IACS) approach was completed. The study confirms that the IACS approach over predicts the loads by up to 40% in Beam Seas and Quartering Seas when other components of IACS rules are not considered. A simplified structural analysis of the DVC model using the Finite Element Method was also completed to demonstrate the effects of the predicted loads on the strength of the hull structure with emphasis on the cross-deck structure, which is the most sensitive structural element of the vessel. Overall, the study highlights the promising characteristics of the DVC concept in comparison to the Round Bilge hull form and provides data required for the preliminary design of catamarans using this concept

Company fundamentals and stock price movements: The role of crude oil prices – Evidence from Nigerian Stock Exchange (NSE)

This study analyzed company fundamentals on how it relates and predict stock price movements and the extent of the role of oil prices in moderating the influence of these company fundamentals in stock price movements. The study covered the period of 2014 to 2018. The study is a panel study. A total of 132 companies were sampled from 196 companies listed on the Nigerian Stock Exchange (NSE) as of December 2018. Data were collected from a secondary source. Multiple linear regression models were used to analyze the data. The study found that a relationship exists between selected companies' fundamentals and stock prices, and oil prices moderate the relationship. But EPS and Working Capital have high predictive power on stock price movements but moderating with oil prices the influence reduces significantly. The study recommends among others that Managers of companies in Nigeria should formulate policies and exert effort geared towards improving company fundamentals in the event of oil prices increases

Liquid Chromatography Mass Spectrometer (Lc/Ms) profile revealed flavonoids and terpenoids with antioxidant potential in aqueous fraction of Combretum micranthum leaf extract

Combretum micranthum (CM) is commonly used for its ethno-medicinal potentials without much or no scientific basis. Thus, the aim of this research is to evaluate aqueous fraction of C. micranthum leaf extract for possible antioxidant compounds using liquid chromatography mass spectrometer technique. In vitro antioxidant was carried out using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric Reducing Power (FRAP) assay methods and the results indicated the free radical scavenging activity of 80.351±0.732 and 0.800± 0.00 at 2.50mg/m1 concentrations which is significantly different when compared to reference standard of 84.718±0.605 and 0.426±0.000 (ascorbic acid) respectively, with concentration or dose-dependent. LC-MS profile revealed the presence of medicinally important compounds like Myricetin (Flavone), Epioxylubimin (Sesquiterpenoids), Furocoumaric acid (Phenolic glycoside) among others. The findings of this study revealed that C. micranthum is rich in potential metabolites and was reflected as its antioxidant potential and could be used for drug and other oxidative stress related management

The moderating effect of brand loyalty on service quality and customer satisfaction in the telecommunications industry in northwest Nigeria

This study investigates the moderating effect of brand loyalty on service quality and customer satisfaction in the telecommunications industry in Northwest Nigeria. A cross-sectional descriptive survey design was utilized, which permits the collection of data from respondents at a certain point in time. The convenience sampling method was used, and structured questionnaires were administered to the customers of Airtel Nigeria telecommunications company using a service performance (SERVPERF) model. Out of the 768 questionnaires administered, 390 valid responses were analyzed, and the hypotheses were tested with the aid of SmartPLS 4. The results for the direct relationships indicate that reliability, assurance, responsiveness, and tangibility were significantly and positively related with customer satisfaction, while empathy had no significant effect on customer satisfaction. For the indirect relationships, brand loyalty was not found to moderate the relationships between the five SERVPERF dimensions and customer satisfaction. The study concludes that regardless of brand loyalty, service quality remains the only driving force of customer satisfaction in the Nigerian telecommunications industry. It is therefore recommended that Airtel should find ways to transcend their competitors and ensure the continued loyalty of their subscribers, especially by tailoring services to customers’ needs. It is also recommended that the company should ensure a pleasant and seamless experience for their subscribers during calls or when accessing the internet. The Nigerian Communications Commission (NCC) should continue to monitor the quality of the services provided by telecommunications companies and sanction those that provide sub-standard services

Labour and Labour Crisis in Nigerian: The Implication of the Structural Adjustment Programme

This Paper Labour and Labour Crises in Nigeria: The implication of structural adjustment programme, its aims at analyzing the effects of the structural adjustment programme (SAP) on the Labour and Labour crises in Nigeria. Through the economic policy programme, which among other objectives of the programmes includes, the privatization of public investment, retrenchment of Staffs, devaluation of the naira, deregulation of interest rates, reduction on government expenditure and Labour market adjustment. This paper also examine the Nigerian economy before the introduction of the Structural adjustment programme (SAP) which also give an insight about the Nigerian drawing rights from 1970 where the 90 percent of the nation foreign exchange earnings and more than 80 percent of the country’s population (53 million) were gaily employed by the agricultural sector. However, with discovery of Oil in the 70s Agricultural contribution to GDP started to decline from about 40 percent, GDP in the early 1970s to 20 percentage in the early 1980s. This decline resulted into untold sequences such as increased dependence on food imports. Now the government source of income solidly depend on Oil with 90 percent of the country exports earnings. As such revenue fell from $27.4 billion in 1950 to$ 11.1 billion in 1982. In the same vein, external reserve dropped from $757 billion to$5.5 billion. These effects resulted into external debt and massive borrowing. In order to find a solution to the problems the government decided to adopt the Structural adjustment programme so that it will dealth with the economic problems as at that time. This also brought about the idea of shifting the resources from undesired sector to more desire ones. Labour in particular is required to shift accordingly from Urban to Rural areas. Government intends to pursue this by applying relative price instrument like devaluation, freeing of urban wages and removal of subsidy. But unfortunately, this result was could not be achieved because of implicit model in pursuing the said objective is defective in many ways. The consequence of these leads to retrenchment of workers where this is not possible, workers were denied their basic pay for months, the Nigeria wage earner was left to fend foe his survival in order to sustain his life and those of his dependents. As such this leads to strike and counter strike which the Labour Union sought to be the only means of obtaining Union rights. Even though this was not effective, since the industries can not affords the exchange rate for their raw materials etc

THE EFFECT OF THREE PRETREATMENTS ON BREAKING SEED DORMANCY OF BAOBAB (ADANSONIA DIGITATA L.)

Objective: Baobab (Adansonia digitata) is a native tree that is found in African savannas, it is a member of family ‘Malvaceae’. The tree is found in Nigeria, South Africa, Botswana, Namibia, Mozambique and in different regions of western Madagascar. Seed dormancy is the most limiting factor for some plants propagation. Dormancy allows seeds to separate from their mother plant and survive dispersal, over distance, and time before growth recommences. This study was aimed to determine the effect of three pre-treatments on breaking the seed dormancy of Adansonia digitata L., a multi-purpose and indigenously endangered tree. Methods: The study was carried out in the greenhouse of the Department of Biological Sciences, Federal University Dutsin-Ma, Nigeria. The three pre-treatments are: Soaking in hot water (100°C) for 5, 10, 15, and 20 min; and soaking in sulfuric acid (H2SO4) and hydrochloric acid (HCL) concentrations (100%, 75%, 50%, and 25%) for 5, 10, 15, and 20 min. Untreated seeds served as control. These were laid out in a complete randomized design with three replications. Data were collected on germination percentage, germination rate, day of emergence, and the average seedlings height. Results: The result showed that earliest mean days of emergence (7 days) were observed in seeds subjected to hot water treatment at 15 min. It also showed the highest rate of germination and percentage 6 (100%). On the other hand, the effect of acids (H2SO4 and HCL) pre-treatments on the seeds gave a fair result (16.66–33.33%), untreated seeds did not germinate. Conclusion: All the pre-treatments used in the study were found to be effective. However, soaking of seeds in hot water (100°C) pre-treatment for 15 min is recommended for breaking the seed dormancy of A. digitata

Inhibitive Effect of Glutaraldehyde on the Corrosion of Aluminum in Hydrochloric Acid Solution

The inhibition effect of glutaraldehyde on the corrosion of aluminum in 1.4 M HCl solution at 308-318 K was investigated by using weight loss method and characterized by Fourier Transform Infrared Spectroscopy (FTIR) & Scanning Electron Microscopic Analysis (SEM). The results show that the inhibition efficiency increases with increasing inhibitor concentration and decreases with rising temperature. The activation energy value was 20.48 kJ mol-1 for the uninhibited acid solution which increased to 33.79 kJ mol-1 in the presence of 0.1 M inhibitor concentration. Langmuir adsorption isotherm was found to provide an accurate description of the adsorption behavior of the investigated inhibitor. The thermodynamic parameters such as adsorption equilibrium constant (Kads), free energy of adsorption (ΔGads), heat of adsorption (ΔHads) and entropy of adsorption (ΔSads) have been calculated and discussed in detail

Experimental and Quantum Chemical Evaluation for Methylene blue Adsorption onto Activated Carbon

The adsorption capacity of black plum seed shell activated carbon (BPAC) was assessed through batch adsorption experiments and quantum chemical computations. Fourier transforms infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) was employed to characterize the adsorbent. In effect of experimental parameters, maximum percentage removal was achieved at optimal levels of contact time (60 minutes, yielding 87.81 %), adsorbent dosage (0.1g, resulting in 94.01 %), initial dye concentration (60mg/L, yielding 87.12 %), and pH 6 (93.18 %). Various kinetic models, including pseudo-first-order, pseudo-second-order, Elovich, and Intraparticle diffusion, were employed to model the adsorption mechanism and kinetic data. Among these, the pseudo-second-order equation proved most effective in describing the dye adsorption onto the employed adsorbent. Equilibrium isotherm data were analyzed using Langmuir, Freundlich, Temkin, and Dubinin-Raduskevich isotherms, with the Freundlich isotherm model providing the best fit. Isotherm parameters were utilized to determine thermodynamic parameters including Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) of adsorption. The thermodynamic values were determined as follows: ΔH = -43.76 kJ/mol, ΔS = -0.148 kJ/K and ΔG = -4.61 kJ/mol, -3.86 kJ/mol, -3.10 kJ/mol, -2.34 kJ/mol and -1.59 kJ/mol at 303, 308, 313, 318 and 323 K respectively. These findings indicate that BPAC is a cost-effective and efficient adsorbent for the removal of hazardous dye from wastewater. Additionally, quantum chemical calculations align well with experimental results, affirming its reliability and simplicity as a method for determining adsorption properties of materials

Inhibitive Effect of Glutaraldehyde on the Corrosion of Aluminum in Hydrochloric Acid Solution

The inhibition effect of glutaraldehyde on the corrosion of aluminum in 1.4 M HCl solution at 308-318 K was investigated by using weight loss method and characterized by Fourier Transform Infrared Spectroscopy (FTIR) & Scanning Electron Microscopic Analysis (SEM). The results show that the inhibition efficiency increases with increasing inhibitor concentration and decreases with rising temperature. The activation energy value was 20.48 kJ mol-1 for the uninhibited acid solution which increased to 33.79 kJ mol-1 in the presence of 0.1 M inhibitor concentration. Langmuir adsorption isotherm was found to provide an accurate description of the adsorption behavior of the investigated inhibitor. The thermodynamic parameters such as adsorption equilibrium constant (Kads), free energy of adsorption (ΔGads), heat of adsorption (ΔHads) and entropy of adsorption (ΔSads) have been calculated and discussed in detail