Arid Zone Journal of Engineering, Technology and Environment (AZOJETE)
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Preparation and Characterization of Steam Activated Chicken Eggshell for Gaseous Pollutant Adsorption
Get PDFAir pollution is a major issue because it can immediately cause health problems. The primary pollutants are oxides of nitrogen, Sulphur, carbon, and oxidants. The collection, preparation, and characterization of chicken eggshell for the production of activated carbon useful in air purification, was carried out. The preparation was done in succession from raw uncarbonized to carbonized and then to steam activated form for adsorption of air pollutants. Powdered Eggshell was Carbonized at different temperatures in the range of 150-600 ºC to achieve optimum and effective temperature for best carbon content from its char. The best carbon yield was gotten at 450 ºC/1 hour in a carbolite type muffle furnace which gives less room for air flow. Thermal / steam activation of the carbonized eggshell was done at 500 ºC for 1 hour. The ash content, bulk density, electrical conductivity, pH, and moisture contents were analyzed respectively. The samples were characterized for their surface area and pore volume. The ash contents for the three samples were in the order Uncarbonized (41.76 %) > Carbonized (32.62 %) > Stean Activated (29.47 %) while the bulk density followed Carbonized (1. 19 g/ml) > Steam Activated (1.11 g/ml) > Uncarbonized (0.79 g/ml). All the three samples had the same value of 0.31 mS/cm for the electrical conductivity while two of the samples (carbonized and activated) had the same pH (8.1) and uncarbonized had a lower pH (7.9). The moisture contents ranged from 2 to 9 % with steam activated sample having the least and uncarbonised, the highest. Tapping density, surface area, pore volume, iodine number, % iodine absorbed values followed the order Steam active > Carbonized > Uncarbonized samples. The steam activated sample having the highest values of all these parameters showed it possesses high adsorption capacity for gaseous pollutants
Kinetic Modeling of Ethylbenzene Isomerization using Bodenstein Approximation Technique
No full textEthylbenzene isomerization reaction is a significant reaction employed in the production of xylene isomers which are used as petrochemical feedstocks. The reaction which proceeds over Pt/Al2O3 catalyst is multi-pathway and multi-cycle in topology. Kinetic model for the reaction was developed in this study using the general rate equation approach. Bodenstein approximation, cross-to-square, and Y-to-delta transformation techniques were used to reduce the complex reaction network to a single cycle network. In addition, the general rate equation for reduced single cycle networks was applied to derive the model for the reaction. The Nelder-Mead simplex optimization technique was used to estimate the kinetic parameters in the model. The structure of the model developed indicates that the model reasonably represents the mechanism of the reaction although few anomalies were observed in the values of the kinetic parameters estimated. The activation energy obtained for the rate constants follows the expected trend for multi-step reactions.
 
Application of SEM/EDS in Fractographic Investigation of TIG Welded AISI 1020 Fusion Zones at Distinct Welding Current Steps
Get PDFHigher arc length is a function of increasing welding current (amperage). It increases the intensity of welding heat, thereby, influencing the microstructure and mechanical properties of the welded material. In this this study, fractographical variations in TIG welded AISI 1020 fusion zones at different welding current steps were investigated using Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) techniques. The fracture morphologies showed a fibrous appearance indicating ductile fracture with initiation of a river pattern of branching cracks, forming cleavages along the crystals plains and intergranular fracture occurring along the grain boundaries, indicating brittle fracture as a result of stepwise increase in welding current. It was observed that the ultimate tensile strength of the welded samples decreased correspondingly from 583.3 MPa, 540 MPa, 530.7 MPa, 506.7 MPa to 473.3 MPa as the resulting heat input due to welding current increased from 96.14 A, 120 A, 155 A, 190 A to 213 A. This indicated that the lowest welding current (96.14A) produced fusion zone with the highest ductility when compared to other welding currents which produced fusion zones that tended to be brittle as a result of increasing heat inputs. It was observed that fusion zone with the lowest welding current showed the appearance of a fibrous structure produced by stretching of crystals in their lattice during heat application. Micro-hardness on the surface of the welds revealed that hardness increased with increase in welding current. Therefore, proper control measures should be put in place to ensure that welding input parameters are optimum.
 
Effects of Rice Husk Ash on Durability of Self-Compacting Concrete Made with Cassava Peel Ash
No full textSelf-compacting concrete (SCC) is a highly flowable concrete with improved strength and surface smoothness. The preparation of SCC requires high amount of cement. This utilizes tremendous amount of energy and releases carbon dioxide into the atmosphere. It is critical to reduce CO2 emissions during Portland cement (PC) manufacture by partially replacing cement in the SCC. This study evaluates the durability characteristics of SCC produced using cassava peel ash (CPA) combined with rice husk ash (RHA) at 5, 10, 15, 20, and 25 percent cement replacement levels respectively. The effects of water absorption, H2SO4 attack, MgSO4 attack, and high heat on SCC made with CPA and RHA blends were examined. The results show that, as CPA and RHA proportions rise by approximately 5% CPA and 10% CPA+RHA substitution, SCC compressive strength equates to design strength (grade 35). It was also discovered that CPA and RHA both enhance resistance to H2SO4 and MgSO4 degradation, but perform poorly when exposed to elevated temperatures when compared to the control specimen. However, when CPA is utilized with RHA in SCC, the rate of water absorption is reduced to a minimum due to an enhanced pore structure of the CPA-SCC specimen. Generally, a 5% CPA content is considered as the optimum replacement of cement for self-compacting concrete with grade 35
Numerical Analysis of a Micro Horizontal Axis Wind Turbine Tower Under Extreme Loads
Get PDFOne of the major challenges in the development of horizontal axis wind turbine is the selection of appropriate and cost effective tower that will elevate the rotor meters above the ground for wind energy harvest. In this work a tubular structural steel material having an external diameter of 0.1 m, internal diameter of 0.092 m and height of 10 m was selected based on cost, mechanical properties and market availability for the tower. Response of this tower material due to simultaneously applied extreme static, dynamic and aerodynamic loading conditions was analyzed in terms of frequency of vibration, deformation and stress using the numerical code COMSOL Multi-physics 5.2. Three dimensional model of the structural steel tower was developed and boundary conditions defined in the numerical code’s model wizard interface. The tower was considered as a cantilever and a static load of 2128.77 N was applied at 10 m height in the plane. Dynamic load of 413.96 N was applied on the tower in the x,y,z planes and an aerodynamic load of 4967.58 N was applied as uniformly distributed loads in the x plane. Extra fine regular quadrilateral mesh was generated for the computation. Frequency response result of the transfer function at 110 GHz excitation shown in terms of electric field norm was uniformly distributed at the outer boundary layer of the tower with a minimum value of 3.7 x 10-79 V/m. The result of the deformation analysis under the predefined extreme loading conditions shows a maximum deflection value of 197 mm at 10 m height and 0 mm at 0 m height of the tower. Additionally, the stress analysis result shows a predicted maximum value 3.28 x 106 N/m2 between 0 m and 1.98 m height of the tower in the wind direction. The deformation was within the elastic limit of the tower material, because the total exerted extreme loads without the self-weight of the tower (2,397.54 N) was less than the determined safe load of the tower (7,107.96 N). The study has established that the selected horizontal axis wind turbine (HAWT) tower material was reliable under the predefined simultaneously applied extreme loads, thus the structural steel tower can function in areas this or similar loading conditions
Evaluation of Concrete Strength with Scarified Road Waste Material
Get PDFThe rising construction materials cost, dwindling materials availability and environmental challenges couple with the serious effect of construction waste have caused a serious concern in the construction industry. Most of the time, repairs of failed road pavements result in generation of Scarified Road Material Wastes (SRMW) and these are usually dumped by the roadsides thus causing environmental issues. These SRMWs could be useful if recycled in the production of concrete but their composition remains a question. Hence, this study seeks to investigate the suitability of SRMW in the production of concrete if used as fine aggregate. The fine aggregate content in nominal concrete mix was altered with SRMW that ranged between 0 – 40 % at an increment of 10%. Similarly, the SRMW was used as an additive in normal concrete mix. The casted concrete cubes of 150 x 150 x 150mm size were tested for strength on 7, 14, 21 and 28 days periods. The experimental results showed that the use of scarified road waste material in lieu of fine aggregates in concrete mixes yielded some promising characteristics. The study revealed that it can be useful in the production of light weight concrete within an optimum range of 10% replacement.
 
Modelling the Performance Characteristics of Four Stroke Internal Combustion Renault Engine Cycle using Matlab Simulation Tool
Get PDFThe trends in Internal Combustion Engine (ICE) cycle is gradually changing due to the quest for optimum performance, efficiency and zero emission level which are often achieved through a series of experimental procedures. To reduce the huge experimental cost, time and resources, MATLAB 2018b was employed in the modelling and simulation process of a four stroke internal combustion Renault engine (Mercedes-Benz 250SE) W108 model. The displaced volume was 4.65x10-4 mm3 (4.65x10-7 cm3) while the minimum volume occupied by the charge was 0.5x10-4 mm3 (5x10-8). Moreover, the maximum velocity occurred at a crank angle of 72º, having a value of 19.65 m/s while the minimum velocity occurred at a crank angle of 288º with a value of -19.65 m/s. However, maximum cylinder pressure of 28 bar was observed at crank angle of 20º, followed by gradual decline up to 0.2 bar at subsequent crank angles of 100, 200, 300º. The results showed that maximum peak pressure between simulated data and experimental data were 5347 and 5320 KPa, while maximum spark pressure in cylinder before combustion between simulated data and experimental data were 1849 and 1730 KPa. In addition, highest crank angle at maximum pressure for simulated and experimental data were 30 and 22º. It has been established that developing mathematical models to simulate IC engine operation cycles can help offset the cost, time and resources required for experimental set up, testing and data acquisition from the engine.
 
Tuning Rules for Fractional Order PID Controllers for Industrial Processes: A Conceptual Framework
Get PDFThis paper presents a brief review of Fractional Order Proportional, Integral and Derivative (FOPID) controllers. The prominent tuning procedures are presented and a conceptual framework for a new design of efficient FOPID controller is presented. The presented framework is based on the concept of output feedback, where a threshold is applied on the output response before feeding its feedback to the comparator. The threshold output was compared with the reference to make a proper decision on when a new controller gain should be selected. This way, control effort will be minimized and the system can settle as fast as possible. This paper presents a brief study of Fractional Order Proportional, Integral and Derivative (FOPID) controllers with their prominent tuning procedures and an introduction to a conceptualize idea for a new tuning technique that can be adopted for efficient tuning this type of controllers... The presented framework is based on the concept of output feedback, where a threshold is applied on the output response before feeding its feedback to the comparator. The idea was to compare the applied threshold output with the reference so as to make a proper decision on when a new controller gain should be selected. The result would be a minimized control effort and thus making the system to settle as fast as possible.
 
Effects of Differently Treated Cassava Flours Blended with Bambara Groundnut Flour on the Bread Making Potential of Two Nigerian Wheat Cultivars
Get PDFStudies involving the use of composite flour for baked goods are unending for reasons such as high quest for functional foods, unsustainable wheat import and nutritional enhancement of baked goods. In this study, cassava flour (CF) was differently treated: roasted (Cr), fermented (Cf), oven dried (Co) and sundried (Cs) before separately blended with flours from de-braned, hammer milled Nigerian wheat varieties, Norman (Wn) and Atilla (Wa) in the ratio of 75:25. The blends (8) were used to bake breads. Refined commercial wheat flour bread was the control. The breads and the flour blends were evaluated for physical, chemical and sensory qualities using standard procedures. Results revealed that the blends had higher ash (0.57-1.31%) and carbohydrate (76.69-81.03%), lower moisture (8.27-10.30%), protein (6.91-10.10%) and crude fat (1.28-2.45%) and desirable higher water and oil absorption capacities (0.85-1.30mg/g) and (1.16-1.40g/g) respectively. There were improvements in the swelling power (6.91-10.10g/g) and solubility (4.00-7.00%) due to CF addition. The ash, protein, and fibre of the treated breads were higher, while the carbohydrate and fat were lower than in the wheat bread. Specific loaf volume (SLV) of wheat bread (2.58ml/g) and bread with oven dried CF (2.61ml/g) were higher; others had lower SLV not significantly different from each other (p>0.05). There were significant increase(p<0.5) in the mineral contents of the composite bread, more in the bread with sun and oven dried CF. The least amounts were recorded in the breads containing fermented CF for obvious reasons. As for wheat flour and the flour blends, they varied respectively: K 84.04-140.56, Ca 20.29-38.79, Mg 17 51-32.32, Fe 2.26-4.91 and Zn 1.40-2.59 (mg/100g) greater in the blends. As for the breads, significant variations were K 157.36-296.29, Ca 22.61-60.94, Mg 32.78-70.54, Fe 2.98-7.47, and Zn 1.56-7.47 (mg/100g) lower in wheat bread and bread containing fermented CF. Wheat bread had superior sensory attributes followed by bread with oven-dried CF but the bread with fermented CF had the poorest sensory ranking. The composite bread had better nutritive value and poorer sensory properties, demanding the use of flavour enhancing agents in order to mask the unpleasant fermented taste and aroma. Addition of dry heat treated CF to wheat flour (25:75) produced bread with overall quality comparable to wheat bread.
 
Simulation Analysis of Benchmark Axial Velocity After Sudden Expansion using Computational Fluid Dynamics
Get PDFComputational Fluid Dynamics (CFD)- ANASYS 2020R1 was used for the analysis of food and drug administration (FDA) benchmark study for biomedical flow transition. An idealized medical device is presented within this study and the CFD predictions of pressure and velocity are compared against experimental measurements of pressure and velocity. The fluid flow transition considered for Reynold numbers(s) 500, 2000, and 6500 with turbulent fluid flow models- laminar, k-omega, k-omega SST and k-epsilon based on throat Reynolds number Reth. 500, 2000 and 6500. Mesh independence K-omega SST model used at 0.0008, 0.0004 and 0.0002 element sizes showed good matched velocity of 5.9m/sec. This converged at 0.0002, which is 2% of total pressure drop. Axial velocity at centreline for Reth 500, 2000 and 6500 at line X =0, showed maximum difference of 77.4% velocity centerline at 0.08m and 19% wall pressure at -0.09m sudden expansion laminar region of Re = 500. Besides, 65.6% and 17.2% obtained at transition Re =2000, showed good agreement between CFD simulations and experimental measurements, at turbulent region Re = 6500, all models were in good agreement at 49.6% velocity centerline and 8.10% pressure drop in laminar region. Also, downstream of the simulation of Reth =6500, other models disappeared which demonstrated K-epsilon model is best at higher Reynolds region. The result revealed negligible pressure gradient at the center line of the wall pressure, and dropped at the normalization point of the experimental pressure data range of 0 to -120n/m2 and balanced at the throat Reynolds number of Reth = 500.