Research Publications (Engineering and Built Environment)
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Item Intelligent transportation system as an effective remedy to improve the public transportation in South Africa(2018) Abejide, O. Samuel; Adedeji, Jacob Adedayo; Mostafa Hassan, MohamedSouth African transportation is generally observed as uncoordinated with hitches and pitfalls. The ease of public transportation movement is highly dangerous with unguaranteed safety and comfort. Despite the funds budgeted for public transport restructuring and management in South Africa running into billions, the situation is still left exasperated. However, the solution to the transport system is rather a long-term infrastructure plan in which improvement can be achieved in a piece meal manner. This study provides a solution to the challenges faced in public transportation by improving the public transport system via application of Intelligent Transportation System (ITS) to improve safety and reduce congestion resulting to a sustainable and efficient transportation system. Quantitative analysis was carried out on public transportation vehicle owners, drivers, public transportation users and non-users within Free State to assess the current state of public transportation that could potentially be solved by ITS and the challenges likely to be faced. The use of questionnaires was used to assist in identifying elements needed for successful integration of ITS into South African Public Transportation.Item Consideration of pavement type service life capacity for sustainable infrastructure development in Nigeria(2019) Abejide, Samuel Olugbenga; Adedeji, Jacob Adedayo; Mostafa, MohamedThe opposition over the use of concrete pavement against the conventional flexible pavement in Nigeria cannot be overemphasized; nevertheless, the question of interest should be: is concrete pavement now a way out of Nigeria road network? Certainly, the success of any road pavement design practice is a function of various factors put together. Yet, the pros and cons of concrete pavement should not be seen from the perspective of a political drive but rather seen on the feasibility of achieving a reliable and sustainable pavement during the intended service life. The necessary factors to be considered in the success of pavement design will depend on; the environmental condition, geotechnical properties of the concrete pavement materials, the mix design of the concrete, the construction practice/workmanship, the expected load cycles and social acceptability. Furthermore, the emphasis on concrete pavement should be as a result of positive success already in use and the viability of the use of concrete pavement over flexible pavement will rely on successes and failures in design and construction which will depend on laboratory testing data so as to generate a code of practice manual which is suitable for a particular geographic location; since soil properties and environmental condition lies in its abundant complexity over a given location. This paper focuses on providing a guide to the use of concrete pavement design in Nigeria and how success in transforming Nigerian roads to rigid pavement can be achieved especially in failed road sections within the southern region and other regions prone to excessive rainfall precipitation.Item A particle swarm optimization approach for model independent tuning of PID control loops(IEEE, 2007-09) Nelendran Pillay; Poobalan GovenderThe paper proposes a model independent tuning technique that yields optimal proportional-integral-derivative parameters for a range of typical process control loops. The proposed tuning technique utilizes the particle swarm optimization algorithm to generate optimal tuning parameters. The PSO tuning method is applied to typical process models. Comparisons are made between the proposed PSO technique and other conventional methods. ©2007 IEEE.Item Vapor-liquid equilibrium data for binary systems of 1-Methyl-4-(1-methylethenyl)-cyclohexene plus {Ethanol, Propan-1-ol, Propan-2-ol, Butan-1-ol, Pentan-1-ol, or Hexan-1-ol} at 40 kPa(American Chemical Society (ACS), 2012-07) Ngema, Peterson Thokozani; Matkowska, Dobrochna; Naidoo, Paramespri; Hofman, Tadeusz; Ramjugernath, DereshIsobaric binary vapor-liquid equilibrium (VLE) data were measured for the 1-methyl-4-(1-methylethenyl)-cyclohexene (d-limonene) + {ethanol, propan-1-ol, propan-2-ol, butan-1-ol, pentan-1-ol, or hexan-1-ol} systems at 40 kPa. A low pressure dynamic still was used for the measurements. The experimental data were regressed using the nonrandom two-liquid (NRTL) and Wilson activity coefficient models. Both models correlated the data well. The 1-methyl-4-(1-methylethenyl)- cyclohexene + {butan-1-ol or pentan-1-ol or hexan-1-ol} systems exhibit a minimum temperature azeotrope. The 1-methyl-4-(1-methylethenyl)-cyclohexene + {ethanol or propan-1-ol or propan-2-ol} systems show the largest positive deviation from Raoult's law, and these systems exhibit no azeotropic behavior. © 2012 American Chemical Society.Item Thermodynamic stability conditions of clathrate hydrates for refrigerant (R134a or R410a or R507) with MgCl2 aqueous solution(Elsevier BV, 2016-04-15) Ngema, Peterson Thokozani; Naidoo, Paramespri; Mohammadi, Amir H.; Richon, Dominique; Ramjugernath, DereshClathrate hydrate dissociation data were measured for systems comprising of refrigerants (R134a, R410a and R507) + water + MgCl2 at varying salt concentrations. The ternary system for R134a + water + MgCl2 was measured at salt concentrations of (0.259, 0.546, and 0.868) mol.kg-1 in the temperature range of (277.1-283) K and a pressure range of (0.114-0.428) MPa. Hydrate measurements for the {R410a or R507} + water + MgCl2 systems were measured at salt concentrations of (0.259 and 0.546) mol.kg-1 in the temperature range of (274.3-293) K and a pressure range of (0.154-1.421) MPa. The isochoric pressure-search method was used to measure the hydrate dissociation data. This study is a continuation of previous investigations which focused on obtaining hydrate dissociation data for R134a, R410a and R507 refrigerants in NaCl and CaCl2 aqueous solutions. The measured hydrate dissociation data can be used to design industrial wastewater treatment and desalination processes. The results show that the effect of salt concentration on hydrate formation is smaller for MgCl2 aqueous solutions compared to CaCl2 and NaCl as salt concentration increases. Modelling of the measured data is performed using a combination of the solid solution theory of van der Waals and Platteeuw, the Aasberg-Petersen et al. model, and the Peng-Robinson equation of state with classical mixing rules. The model is in good agreement with the measured hydrate dissociation data.Item Vapor-liquid equilibrium data for binary systems of n-Dodecane + {Propan-1-ol, Butan-1-ol, 2-Methylpropan-1-ol} at 40 kPa(American Chemical Society (ACS), 2014-05) Tebbal, Zoubir; Ngema, Peterson Thokozani; Narasigadu, Caleb; Negadi, Latifa; Ramjugernath, DereshIsobaric (T-x-y) binary vapor-liquid equilibrium (VLE) data were measured and modeled for the n-dodecane + {propan-1-ol, butan-1-ol, or 2-methylpropan-1-ol} systems at 40 kPa. A low pressure dynamic still, capable of measuring systems of high relative volatility, was used for the measurements. The vapor and liquid equilibrium compositions were determined using a gas chromatograph with a thermal conductivity detector. The experimental data were regressed using the combined method (γ-φ approach). The nonrandom two-liquid (NRTL) activity coefficient model was used to describe the liquid phase nonideality, and the vapor phase was assumed to be ideal. The NRTL model parameters were determined using nonlinear least-squares regression. The experimental data were found to be well correlated with the thermodynamic modeling. No azeotropic behavior has been observed. The three investigated systems show a large positive deviation from Raoult's law. © 2014 American Chemical Society.Item Vapor-liquid equilibrium data for binary systems of 1H-Pyrrole with Butan-1-ol, Propan-1-ol, or Pentan-1-ol(American Chemical Society (ACS), 2012-09) Zawadzki, Maciej; Ngema, Peterson Thokozani; Domanska, Urszula; Naidoo, Paramespri; Ramjugernath, DereshIsobaric and isothermal vapor-liquid equilibrium (VLE) data are presented for binary systems comprising 1H-pyrrole (pyrolle) with light alcohols. The systems measured include 1H-pyrrole + butan-1-ol at 40 kPa and T = (353.2, 363.2, and 373.2) K; 1H-pyrrole + propan-1-ol at 40 kPa and T = (348.2, 358.2, and 368.2) K; and 1H-pyrrole + pentan-1-ol at 40 kPa and T = (353.2, 363.2, and 373.2) K. Measurements were undertaken on a low-pressure dynamic still, with analysis of the equilibrium samples by gas chromatography. The 1H-pyrolle + butan-1-ol and 1H-pyrolle + pentan-1-ol systems exhibited azeotropic behavior for both the isobaric and the isothermal measurements. The measured data were modeled using the Wilson and nonrandom two-liquid (NRTL) excess Gibbs energy models, with both models correlating the data well. © 2012 American Chemical Society.Item Isothermal method for hydrate studies using a transparent variable volume cell(AIP Publishing, 2014-04) Ngema, P. T.; Nelson, W. M.; Naidoo, P.; Ramjugernath, D.; Richon, D.The measurements of hydrate dissociation points are generally achieved using the well-established isochoric method. This method implies determination of the total pressure of the system under study, as a function of temperature. It is quite time consuming, especially at higher pressures. Working at higher pressures requires equilibrium cells with thicker walls, which compromises on fast heat exchange. The use of a variable volume cell is therefore quite attractive as it allows for the measurements of hydrate dissociation pressure under isothermal conditions. This paper describes a transparent variable volume cell used for efficient and rapid measurements via the isothermal procedure.Item Phase stability conditions for clathrate hydrate formation in (fluorinated refrigerant plus water plus single and mixed electrolytes plus cyclopentane) systems : experimental measurements and thermodynamic modelling(Elsevier BV, 2019-09) Ngema, Peterson Thokozani; Naidoo, Paramespri; Mohammadi, Amir H.; Ramjugernath, DereshPhase equilibrium conditions (dissociation data) for clathrate hydrates (gas hydrates) were studied for systems involving fluorinated refrigerants + water + single and mixed electrolytes (NaCl, CaCl2, MgCl2 and Na2SO4) at varying salt concentrations in the absence and presence of cyclopentane (CP). The ternary systems for (R410a or R507) + water + CP were performed in the temperature and pressures ranges of (279.8–294.4) K and (0.158–1.385) MPa, respectively. Measurements for {R410a + water + (NaCl or CaCl2) + CP} were undertaken at salt concentrations of (0.10, 0.15 and 0.20) mass fractions in the temperature and pressure ranges of (278.4–293.7) K and (0.214–1.179) MPa, respectively. The temperature and pressure conditions for the (R410a + water + Na2SO4) system were investigated at salt concentration of 0.10 mass fraction in range of (283.3–291.6) K and (0.483–1.373) MPa respectively. Measurements for {(R410a or R507) + water + mixed electrolytes NaCl, CaCl2, MgCl2} were undertaken at various salt concentrations of (0.002–0.15) mass fractions in the temperature and pressure ranges of (274.5–292.9) K and (0.149–1.119) MPa in the absence and presence of CP, for which there are no published data related to mixed salt and a promoter. The phase equilibrium measurements were performed using a non-visual isochoric equilibrium cell and the pressure-search technique. This study was focused on obtaining equilibrium data that can be utilized to design and optimize for water desalination process and the development of a Hydrate Electrolyte–Cubic Plus Association (HE–CPA) Equation of State based model. The results indicate hydrate dissociation pressure reduction/hydrate dissociation temperature increase up to ambient conditions in the presence of promoter (CP). The experimental results were then modelled. The modelling results are in good agreement with the measured hydrate dissociation data.Item Re-constructing the use of educational technology in the deprived engineering classroom(2018-11-01) Fomunyam, Kehdinga GeorgeThe use of educational technology in classrooms is gaining grounds in the world. Educational technologies such as Intercom, Internet use, Email, use of phones and tablets for research, video chats, YouTube video lesson, WhatsApp discussion groups and many others are used today to enhance learning. Despite this rapid embrace and use of technology, the bone of contention in this paper is that engineering classrooms in Cameroon are still being deprived of educational technology. The research sought out to examine the reason for this nonexistence of educational technologies in classrooms as well as state the advantages that accrues from using educational technology in deprived engineering classrooms in Cameroon. Data was collected through semi-structured interviews with final year engineering students and their lecturers, transcribed and analyzed using the qualitative analytical approach. The study reveals that ignorance of the significance of educational technology, fear of being replaced by the new technology, stiff administrative grip on funds for these technologies are some of the reasons why some engineering classrooms are deprived of educational technology. The advantages include: time serving, access to alternative educational materials, audio-visuals, knowledge sharing with distant and foreign students, an increase in on-line course availability and learning activities, the growth of interactive communications usage, a growing dependence on distant interactions and non-face-to-face learning, increasing numbers of international education and business relationships and partnerships. The article recommends that the reconstruction of educational technology in engineering education in Cameroon needs to be embraced by school authorities, and classroom teachers. It should begin with school administrators who should be intentional about introducing this alternative education technology in their institutions.