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Hybridization of aluminium matrix composite is with a view to offset the properties deficient in one composite reinforcement. The present investigation involves a comparative study of AA6063 matrix composites with single reinforcement of Al2O3, SiC, graphene respectively and various hybridized proportions of the same reinforcements. Physical (density and %porosity) and mechanical (tensile strength, fracture toughness, %elongation, elastic modulus, etc.) properties of composites developed via solidification processing technique were evaluated. The porosity of all the composites falls below the maximum acceptable limit for cast metal matrix composite. Maximum values for UTS, %elongation and absorbed energy at maximum stress was obtained by hybrid composite with 4wt% Al2O3, SiC and 2wt% graphene, while the composite with the highest single reinforcement of graphene have the highest value for elastic modulus and fracture toughness. Numerical optimization results show that a matrix and hybrid reinforcements contents of AA6063 (91.413wt.%), SiC (3.679wt.%), Al2O3 (0.277wt.%), and graphene (4.632wt.%) respectively, will result in optimal values for the evaluated properties.

Waste wigs are often disposed of in their volume in landfills, thus constituting a nuisance to the environment. Recycling these wigs in masonry bricks is a way via which they can be recycled and reused. On such premises, waste wig fiber (WWF) was recycled by incorporating it into the cement-sand-clay composite mix for masonry brick production. The challenges masonry bricks face include shrinkage and water susceptibility, hence the contributory effect of WWF on physio-hydric properties was assessed in this study. Sample preparation entailed the blending of cement, sand, clay soil, and waste wig fiber. The control mix was prepared by commixing clay with 10 % cement (by clay volume) and 20 % sand (by clay volume). Other mix proportions were reinforced with 1, 2, 3, 4, and 5 % WWF by clay volume. Prepared composites brick samples were cured for 28 and 56 days and tested for physio-hydric properties. Results revealed that WWF contributed significantly to improving hydro-resisting properties by minimizing porosity, water and moisture absorption, capillary suction, and water permeability. Furthermore, WWF contributed to dimensional stability by reducing shrinkages and weight loss. Hydration time impacts significantly in reducing apparent porosity, water permeability coefficient, moisture and water absorption, capillary suction coefficient; increasing apparent density, weight loss, linear, and volumetric shrinkage. Prolonged time in water ensued higher water absorption. The general outcome depicts that WWF showed promising performance in bricks developed in enhancing water and moisture susceptibility resistance and promoting mass and dimensional stability; hence, it can be employed in reinforcing cement adobe bricks.

The effects of the addition of different percentage compositions of graphene nanoplatelets (GNPs) to a nickel-based superalloy were investigated in this study. A spark plasma sintering (SPS) method was employed in the development of the nickel-based alloy/composites, and the developed bulk nickel-based alloy and its composites were from high-purity micron-size powder. Subsequently, the microstructure and mechanical properties (i.e., microhardness and tensile yield strength) were examined. The SPS-processed nickel-based alloy/composite samples exhibited high densification ranging from 97.64 to 98.87 pct. The addition of GNPs greatly influenced the microhardness results, which ranged from 384 to 459 Hv, and the tensile yield strength between 675 and 883 MPa. The results indicated that the addition of graphene nanoplatelets played a significant role in the microstructure and mechanical properties of spark plasma-sintered nickel-based composites. The addition of graphene nanoplatelets caused grain boundary strengthening, load transfer from the matrix to GNPs, and grain boundary strengthening by impeding dislocation movement. Coupled with the improvement caused by GNPs is the enhancement of the mechanical properties of the materials developed as a result of the high relative density values obtained.

This work investigated the dry sliding wear behaviour of spark plasma sintered (SPSed) Ti-Ni binary alloys produced at varying nickel content with alloy steel ball as the counterface material, at room temperature under varied applied normal loads. Finite element modeling was used to investigate the high-velocity impact response of the sintered alloys due to the dimensional constraint associated with SPSed samples. Microstructural analysis results revealed the presence of intermetallic phases of Ti-Ni with increasing nickel content. The best wear resistance ranging from 0.25 x 10-3 mm3/Nm to 0.22 x 10-3 mm3/Nm across all applied loads was obtained in Ti-6Ni alloy. This was attributed to the compaction of the protective triboxide and carbide layers on the surface of the sample. Oxidative and wear by adhesion were observed at low applied normal load while at high loads the prevalent wear mechanism was abrasive with reduced influence of oxidative and adhesive wear. Finite element analysis results also showed that Ti-6Ni alloy possessed the optimum combination of absorbed energy and ductility to reduce the possibility of brittle failure under impact loading. Keywords: Ti-Ni binary alloys; Spark plasma sintering; Dry sliding wear; High-velocity impact; Finite element analysis.

The present study reports on the mechanochemical processing and characterisation studies of Si-based refractory compounds derived from sugarcane bagasse (SCB). SCB was preliminarily washed and sun-...

This review provides information on spark plasma sintering (SPS) as a novel approach for polymer and polymer composite manufacturing. Over the years, the potential of this technique has been widely researched and attested for fabricating different metallic and ceramic-based composite without much emphasis on polymers. However, in recent times, this process has been employed to solving numerous challenges encountered while engaging the conventional polymer processing technique such as compression, injection moulding and extrusion in processing high viscous polymers and others. The numerous merit of this process, its mode of operation and applications are thoroughly explained in this review. It also evaluated the outstanding performance and unique properties obtained from the spark plasma-sintered polymer specimen when compared to the conventional polymer processing techniques. It was hence discovered that the thermoelectric properties, thermal conductivity, thermal stability, crystallinity, microstructural, mechanical and tribological properties of the polymer can be greatly enhanced through this process compared to other conventional means. This review will help polymer scientist, industrialist and engineers to properly understand and explore this alternative route in solving many material development challenges.

This chapter introduces the importance of casting process, particularly in ferrous foundries. It opens with a high level functional classification of casting processes, with focus on squeeze casting, and its application in the design of metal matrix composites. To lay a suitable foundation on the subject, detailed discussions on the process parameters, process sequence, cost effectiveness, factors governing the selection of the process, associated casting defects, merits and demerits of the process are included. Special emphasis is given to discussions on the casting defects remedial measures and casting quality, types of squeeze casting processes, differences between them, area of application and components that can be manufactured using squeeze casting. The chapter closes with a brief discussion on the future trends and opportunities for improving the squeeze casting process.

This work focused on the mechanical and corrosion behaviors of electroplated nickel on heat-treated low carbon steel serving as an alternative to austenitic stainless steel for the yam beater in a yam pounding machine. Four standard samples were prepared for electrodeposition from the steel samples by heating to a temperature of 920°C with a 60-min holding time. One of the samples was air-cooled while the remaining three were quenched in H2O and later tempered at 450°C, 550°C and 650°C for 60[Formula: see text]min. After the heat treatment process, the ultimate tensile strength, toughness, and microhardness of the samples were obtained. Nickel electrodeposition was later carried out on the heat-treated mild steel using Watt standard bath concentration. Optical Microscopy (OM) and Scanning Electron Microscope equipped with energy dispersion spectroscopy (SEM/EDS) were used for the characterization of the heat-treated and nickel-electrodeposited samples. More so, the electrochemical behavior of the nickel-plated samples was studied in a yam fluid environment using the potentiodynamic polarization technique. X-ray fluorescence (XRF) was used to analyze the chemical and oxide composition of the samples. The results showed that among all the heat treatment operations, the sample heat-treated at 920°C and tempered at the highest tempering temperature of 650°C gave the highest toughness value (102[Formula: see text]MJ/m3) when compared with stainless steel at 124[Formula: see text]MJ/m3. The sample heat-treated at 920°C and tempered at 550°C displayed a corrosion rate of 0.022182[Formula: see text]mm/yr as against the stainless steel sample with a value of 0.0031864[Formula: see text]mm/yr. From the analysis, the nickel deposited on the heat-treated samples enhanced corrosion resistance in the yam fluid. XRF analysis of the yam before pounding, after processing with nickel electroplated, and stainless beaters shows the content of nickel as 0.0941%, 0.109%, and 0.1113%, respectively. It was concluded that the materials for the yam pounding beater, therefore, perform better if they were both heat-treated and nickel-plated. Invariably, stainless steel could be successfully replaced with heat-treated and nickel-plated mild steel for use as a yam pounding beater.

This study aims to investigate the effects of powder particle size on the densification and microhardness properties of spark plasma sintered superalloy. Three particles size ranges of nickel were used in this study, namely, (3-44, 45-106 and 106-150 μm), and this is the matrix in the IN738LC superalloy composition (powder), used in the study. The effects of the particle size were examined at a specific applied temperature and pressure. The transitioning stages during the sintering process of the green powders to the formation of the sintered alloy were analyzed and given as the particle rearrangement stage, the localized deformation stage and the neck formation/grain growth stage. There was the formation of γ, γ' and a solid solution within the microstructure of the sintered alloys. The effect of particle size was more pronounced on the grain sizes obtained, while the phases formed is the same for the three alloys. The results indicate that the nickel particle size (>60% of the total composition) has a significant influence on the densification, porosity, grain size and hardness properties of the IN738LC sintered alloy. Finer nickel particle size resulted in a sintered product with smaller grain size (9 µm), reduced percentage porosity (3.9%), increased relative density (96.1%) and increased hardness properties (371 Hv).

Mechanical behaviour of fired bricks containing varied amount of fine sand (FS) and waste glass powder (GP) was investigated. FS and GP were added to bricks at varied amount of 0, 5, 10, 15, 20, 25, 30, 35 and 40 wt. %. Firing was done at 1200 ⁰C and samples produced were evaluated for compressive and flexural strengths while microstructural analyses of 25 wt. % FS and GP-clay bricks were examined. Results showed that compressive strength was highest at 30 wt. % GP for GP-bricks while for FS-clay bricks, compressive strength rose to 35 and 40 wt. % FS addition. Flexural strength for GP-clay and FS-clay bricks peaked at 30 wt. % GP (3.63 MPa) and 40 wt % FS (2.45) respectively. Flexural modulus increased progressively and exponentially as FS and GP proportion increased. Workdone in resisting deformation and deflection during bending reduced with increased amount of both additives. Flexural strain was inversely related to load and stiffness. In conclusion, addition of GP and FS in increasing amount resulted in improved mechanical properties in the bricks. Also, increased proportion of GP and FS was found to improve response to loading in fired bricks.

Polypropylene composites reinforced with coir fibre and yam peel particulate were produced using compression moulding machine. Treated and untreated coir fibres were used; 1.5 M NaOH was used for the treated coir fibres. Yam peel was grouped into two, treated and untreated; the treated was modified using 1 M solution of NaOH and HCl in the proportion of 30% and 70%, respectively. The yam peel which was sun-dried for 14 days was pulverized and sieved to −45 µm. Samples were developed using treated and untreated reinforcements (TCF/YPP and UCF/YPP) at constant coir fibre proportion (15%) and varied amount of yam peel particulate (2, 4, 6, and 8 wt.%). The hybrid composite samples developed were probed for mechanical properties and thermal and wear behaviour. The level of particles agglomeration at the fibre-matrix interface was examined using scanning electron microscope. The results show that sample reinforced with treated 4 wt.% coir fibre and yam peel particulate had optimum mechanical properties. However, the thermal conductivity of composite samples increased with fibre addition. All composite samples developed had better resistance to abrasion when compared to the control sample.

In this work, the synthesis, characterization and mechanical properties of sintered In situ Ni-based quaternary superalloy (Ni–9Fe–22Cr–10Co) were studied. All the Ni–9Fe–22Cr–10Co quaternary alloy specimens were consolidated via spark plasma sintering technique at temperature range and sintering pressure of 850–1100 °C and 50 MPa, respectively. The densification of sintered alloys was obtained through Archimedes technique while the micro-indentation hardness of the alloys was conducted using Vickers microhardness tester. The specimens were characterized using the optical microscope and scanning electron microscope equipped with energy-dispersive spectroscopy while the phase identification was carried using X-ray diffractometer. The microstructural characterization results revealed that the relative density, surface morphology as well as the micro-indentation hardness properties depend on the sintering temperature. In addition, it was observed that high sintering temperature aided grain refinement and bulk compaction of the material leading to high relative density. XRD analysis shows the formation of Ni–Fe and Co–Fe as the major phases. Generally, the densification and grain size of the alloys increased with increasing sintering temperature with optimum results obtained at a temperature of 1100 °C and sintered density of 98% while the maximum Vickers hardness value of 439.17 HV1 was recorded.

Waste wig fibers, empty eggshell powder and waste paper were recycled in the development of composite boards as potential sustainable material for wall partitioning. Samples were produced by blending these wastes with cement in the presence of water and cured for 14 and 28 days. The samples produced were examined for density, porosity, thickness swelling, internal bonding strength, modulus of rupture and elasticity in line with standard procedures. From the result obtained, there was reduction in porosity, thickness swelling, while internal bonding strength and modulus of rupture and elasticity were enhanced. An optimum value for modulus of elasticity was attained at 0.96 g/cm3 (3.85 MPa for 14 day curing and 3.5 MPa for 28 day curing), even as internal bonding strength increases with increasing density. It was therefore concluded that recycling of these wastes is effective in the development of sustainable materials for wall partitioning.

This work investigates the influence of blending waste paper and cement at fixed proportion with varying proportions of chicken feather fiber (CFF) and wood saw dust (WSD) as reinforcements. Samples produced were tested for flexural properties and water absorption potentials. The outcome showed that with increasing CFF content and reducing WSD content, water absorption reduced while flexural strength, modulus of ruptures (MOR) and modulus of elasticity (MOE) increases. MOR and MOE were at peaked when the ratio of CFF to WSD was 3:2 while flexural strength reached it crescendo at 4:1 of CFF to WSD. It was noticed that higher CCF content from 3 to 5 wt% gave better results in most of the investigated properties compared to WSD. Therefore, it was concluded that low quantity of WSD is needed to form a synergy with CFF in order to achieve optimum results. Well dispersed CFF-WSD phase in waste paper-cement based composites was observed to be responsible for the enhancement in the investigated properties.

Recent advances in titanium alloy applications in the offshore industry have been realized through the development of laser surface modification technique. The distinctive outcome of this technique has provided increase in the utilization of titanium in offshore drilling risers for special drilling operations and various subsea and tubing applications. In this work, surface mitigation and corrosion degradation of titanium alloy in aggressive sulfuric acid were investigated using electrochemical technique (linear potentiodynamic polarization) while the surface characterization (morphology) and phases of the resultant coatings were analyzed using X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Prior to that, laser surface technique was used to fabricate Nickel-based powder on the substrate (Ti-6Al-4V). Results revealed that laser clad sample with high scan speed was more effective in improving the corrosion resistance compared to low scan speed. The enhanced corrosion resistance with high laser scan speed has been attributed to the presence of hard intermetallic compounds in the metallic coating.

Non-isothermal kinetic parameters of the pyrolysis process of Tectona grandis were evaluated with different model-fitting methods. The thermal degradation of the Tectona grandis was examined using a thermogravimetric analyser. Pulverized Tectona grandis (6.5 mg) was heated from 30 to 800 °C at varying heating rates (5, 10 and 15 °C / m i n ) in an inert environment. The results depicted that heating rate has no effect on weight loss during the reactive drying zone. However, as the thermal analysis progressed into the active pyrolysis and passive pyrolysis zones, the weight loss decreased with increase in heating rate. The kinetic parameters evaluation revealed that the GB model was best fit to evaluate the kinetic parameters of teak in the active pyrolysis zone, while GB and Mampel models were considered most appropriate for the evaluation of the kinetic parameters in the passive pyrolysis zone. Model-fitting method has the capacity to capture wide range of fractional conversion.

Graphene/Inconel 738LC composites were synthesized using spark plasma sintering technique and the microstructural features were investigated using Optical microscope, Scanning electron microscope and X-ray diffraction machine. The microhardness, porosity and fracture toughness of the graphene-reinforced Inconel 738LC matrix composites were obtained. The processing parameters used were sintering pressure of 40 MPa, heating rate of 100 °C/min, soaking time of 5 min and varied sintering temperatures between 1000 and 1100 °C. The results show that spark plasma sintering is a viable powder metallurgy technique to develop graphene-reinforced Inconel 738LC composite. The increase in sintering temperature shows that there was significant increase in the hardness property of the sintered composites while the porosity and fracture toughness significantly reduced. Intermetallic and solid solution phases were formed within the microstructure which enhanced the strength of the sintered composites. In this study, the highest microhardness value (469 Hv), lowest porosity (1.47%) and fracture toughness value (26) was obtained in the composite sintered at 1100 °C.

The quest to reduce the energy consumption in automotive has resulted in the development and use of lightweight materials for the design of vehicles. Also, stiffer legislation is being put in place to enforce the utilization of lightweight components for vehicles in order to guarantee the safety of both pedestrians and passengers. Hence, the bumper beams of a vehicle which is a major contributor to its total weight must be made of lightweight materials capable of absorbing kinetic energy developed during a collision. In this paper, the impact response of a double hat bumper beam made with two different materials, aluminium Al (3105-H18) and carbon fibre-epoxy composite and subjected to a high-velocity impact was simulated using finite element analysis code, Abaqus CAE/2019. The response of both materials was compared, and the results show that carbon fibre-epoxy composite absorbed equal amount of energy as aluminium during collision and thus, can be used as a bumper beam for vehicles.

Preservation of surface integrity of engineering assets has been achieved by laser cladding of nickel matrix composites in recent years. Ceramic-metal (cermet) coatings offer outstanding surface performances, improved mechanical, thermal and tribological capabilities. In this study, nickel matrix composites with two different compositions of an ultra-high temperature boride reinforcement namely, ZrB2, was considered. Laser cladding of Ni-ZrB2 binary coatings was successful. The microstructural orientation of the coatings was studied as scanning electron microscopy revealed the general transition of mixed cellular grains and dendrites to fine crystals with increasing depth from the free surface towards the substrate. It was observed that the interfacial region of Ni-10% wt. ZrB2 coatings were characterized by smaller cellular grains. Microhardness, oxidation behaviour and tribological tests were conducted on coatings containing 5 and 10% wt. ZrB2. Phase analysis displayed the secondary phases formed within the cermet coatings, which were responsible for the improved microhardness of Ti-6Al-4V alloy. Furthermore, the effect of scanning speed during laser cladding was investigated. Results revealed that Ni-10% wt. ZrB2 fabricated at a deposition speed of 1.2 m/min showed the most suitable surface performance amongst the cermet coatings.

Functional and morphological characterization of wood charcoal/periwinkle shell (WC/PWS) particles hybrid reinforced polyester matrix composites was successfully developed. Characterization tools such as energy dispersive x-ray spectrophotometer (EDXRF), Fourier transform infrared spectrometer (FTIR) and scanning electron microscope (SEM) coupled with EDS elemental detector were used to examine the composites developed. The EDXRF identified iron, copper, zinc, calcium and CaO, Fe2O3, CuO, ZnO as primary elements and oxide constituents of WC. Also, calcium, strontium, iron and CaO, SrO, Fe2O3 and Al2O3 as the basic elements and oxides contents of PWS. It is evident that these elements and oxides constituents influenced significantly the mechanical properties of reinforced polymer composites. The EDS mapping also confirmed the major elements identified by EDXRF analysis. Hybrid composites reinforced with 75/25 and 50/50 WC/PWS ratio show stronger interfacial bonding and interlocking due to even dispersion of the filler particles revealed by SEM images. The functional assessment revealed minor shifts in the frequency bands of functional groups present in the unreinforced polyester matrix largely due to interactions of the hybrid fillers with the matrix.

Commercially available coals were characterized in this study in order to ascertain their suitability as carbonaceous materials for direct reduced iron (DRI) production. The proximate, elemental and heating value analyses were carried out based on different ASTM standards. Fourier transform infrared spectrometer and scanning electron machine equipped with energy dispersive x-ray spectroscopy (EDX) spectrometer were further used to obtain the structural components and elemental contents. The samples possess moisture content (2.16–2.41%), ash (78.88–86.28%), and fixed carbon (1.22–4.38%). The samples contain carbon in the range of 1.18–5.24%. The heating values of the sample were in the range of 0.45–1.94 MJ/kg. The predominant functional group in the samples were Si-C and Si-O-Si at 722–817 cm−1 and 1200–1050 cm−1, respectively. The micrographs of the samples also displayed agglomeration of silica and carbide with silicon and aluminum dominating the EDX spectra. It was concluded that the samples characterized in this study were not coals but they belong to the clay/sedimentary rock family. Thus, they are not suitable as carbonaceous material for DRI making.

This study aims to investigate the microstructure, corrosion and tribological properties of spark plasma sintered graphene nanoplatelets (GNPs) reinforced Inconel 738 low carbon composites. The matrix and reinforcement were thoroughly milled in order to ensure homogeneity. Thereafter, the milled powders were consolidated by using spark plasma sintering. The microstructural evolution and the phases formed were examined by the using scanning electron microscopy and X-ray diffractometry techniques. The corrosion analysis was investigated in acidic and basic media, while the tribological test was conducted under dry sliding conditions at varying loads. The results show that the microhardness values were significantly influenced by varying the GNPs constituents in Inconel 738LC from 384 to 459 HV0.5, while the sintered density was influenced by the sintering parameters. The corrosion response of the sintered composites in both acidic and basic media are comparable, irrespective of the varying GNPs content in the matrix. The wear performance suggests that the addition of GNPs to IN738LC, greatly enhanced the wear resistance and reduced the friction coefficient of the sintered IN738LC-GNPs composites. The improvement is attributed to the influence of the graphene-based tribofilm that formed on the sliding contact interface, which reduced friction coefficient. Likewise, graphene has a slight potential of forming continuous tribofilms at the friction interface due to its lubricity. It is thought that the GNPs reinforcement reduced the pull-out tendency, during wear activities.

Effects of elevated temperature on thermo-mechanical properties of fired ceramic products reinforced with waste glass powder (WGP) were reported. Samples were produced by the addition of WGP to clay in varied amount and oven dried samples were fired in an electric furnace which was operated 1200 oC. Compressive and flexural strength were examined at room temperature and at elevated temperatures of 100, 300, 500, 700, and 900 oC. Results showed that, compressive strength and flexural strength reduced at elevated temperatures. Thermal conductivity, diffusivity, and emissivity were higher with increasing WGP content, while thermal expansivity and specific heat capacity were lower as percentage WGP increased in the samples. Results on thermal shock resistance showed that WGP reduced shock resistance in the samples, while the cooling rate increased with the percentage addition of WGP. Impact resistance was noted to decrease in samples when fast cooled from high temperature as the rapid cooling rate was observed to increase with WGP addition in samples. It was concluded that for fired clay products incorporated with WGP, the operating temperature should not exceed 700 oC. Also, in an environment whereby cooling is done by air or/and water, an operating temperature of ≤ 300 oC was recommended.

Chromate conversion coatings have witnessed limited acceptability in recent times. The coatings contain Cr (VI) species that have been classified as environmental hazards and injurious to human health. Thus, the use of environment-friendly and non-carcinogenic novel inorganic-inorganic hybrid conversion coatings are being explored. Vanadate (VCC), hybrid Vanadate/Molybdate (HCC) conversion coatings on Al6061 have been classified in terms of corrosion and adhesion performance with reference to the untreated alloy. Natural exposure tests in the atmosphere and stagnant near-neutral 3.5% sodium chloride solution, as well as potentio-dynamic polarization measurements showed that the corrosion rate for HCC is lower for Vanadate, which in turn outclassed the ‘bare’ alloy. However, clusters of passive incipient pits were revealed on the former after 120 h of exposure in stagnant chloride solution. Both conversion coatings outperformed the untreated aluminium alloy after atmospheric corrosion and adhesion tests.

The present study assessed the potential of engaging response surface analysis in the experimental design, modeling, and optimization of the strength performance of aluminum-7075 green composite. The design of the experiment was carried out via the Box–Behnken method and the independent variables are rice husk ash (RHA) at 3–12 wt.%, glass powder (GP) at 2–10 wt.%, and stirring temperature (ST) at 600–800 °C. Responses examined are yield, ultimate tensile, flexural, and impact strengths, as well as microhardness and compressive strength. ANOVA analysis revealed that the input factors had consequential contributions to each response, eventually presenting regression models statistically fit to represent the experimental data, further affirmed by the diagnostic plots. The result of the optimization envisaged an optimal combination at 7.2% RHA, 6.2 GP, and 695 °C with a desirability of 0.910. A comparison between the predicted values for the responses and the values of the validation experiment revealed an error of

The mechanical and thermal properties of clay bricks are important parameters that influence the durability and energy consumption of building bricks in service. This study investigates the...

To enhance the energy security and promote energy diversity, biomass sources of energy are viable resources worldwide. Bioenergy is an organic source of power derived from various feedstock including fuel wood, energy crops, solid wastes, and residues of plants. This book chapter explores the use of biomass in Africa and the technical and economic potential of these resources for energy supply in the continent. Findings of literature revealed that the potential of biomass is high in Africa due to availability of land, its preference due to limited electricity supply and the exorbitant nature of fossil fuels, the assorted variety of energy crops suitable for growth in the continent and the green nature associated with the resource. The chapter also established that bioenergy is renewable and not carbon neutral. As such, accurate computation of its resultant greenhouse gas emissions based on their sequestration and emission rates is strongly advised to optimize biomass for energy utility and sustainability compared to conventional energy sources.

In this study, an investigation was carried out on the effect of waste glass particles (WGP) (sieved to -23 µm) with varying proportions of 2, 4, 6, 8, and 10 wt.% on the properties of Al-6061 alloy. The produced composite samples were subjected to various tests; density, porosity, tensile, impact, compression, and wear. The results showed that increasing the addition of waste glass led to a progressive reduction in density, elongation, strain, and impact energy as WGP increased from 0 to 10 wt.%. The Brinell hardness was observed to increase progressively from 0 to 10 wt.% of WGP. There was an enhancement of yield and ultimate tensile strength, peaking on an incorporation rate of 6 wt.% WGP after which the strength deteriorated. As in the case of yield and ultimate compressive strength, the maximum value was realized at 8 wt.% WGP addition while 10 wt.% led to a fall in strength. Analysis of wear performance revealed a lower wear rate at the lowest variables of applied load, sliding velocity, and distance. It was further observed that increasing the WGP content has resulted in a better reduction of wear. Therefore, waste glass particle infusion of Al-6061 is good for enhancing the properties of the alloy for engineering applications.

In a bid to develop paper bricks as alternative masonry units, unmodified banana fibers (UMBF) and alkaline (1 Molar aqueous sodium hydroxide) modified banana fibers (AMBF), fine sand, and ordinary Portland cement were blended with waste paper pulp. The fibers were introduced in varying proportions of 0, 0.5, 1.0 1.5, 2.0, and 2.5 wt% (by weight of the pulp) and curing was done for 28 and 56 days. Properties such as water and moisture absorption, compressive, flexural, and splitting tensile strengths, thermal conductivity, and specific heat capacity were appraised. The outcome of the examinations carried out revealed that water absorption rose with fiber loading while AMBF reinforced samples absorbed lesser water volume than UMBF reinforced samples; a feat occasioned by alkaline treatment of banana fiber. Moisture absorption increased with paper bricks doped with UMBF, while in the case of AMBF-paper bricks, property value was noted to depreciate with increment in AMBF proportion. Fiber loading resulted in improvement of compressive, flexural, and splitting tensile strengths and it was noted that AMBF reinforced samples performed better. The result of the thermal test showed that incorporation of UMBF led to depreciation in thermal conductivity while AMBF infusion in the bricks initiated increment in value. Opposite behaviour was observed for specific heat capacity as UMBF enhanced heat capacity while AMBF led to depreciation. Experimental trend analysis carried out indicates that curing length and alkaline modification of fiber were effective in maximizing the properties of paperbricks for masonry construction.

Bamboo fibers (BF) treated in 1.3 Molar NaOH and particulate coconut shell (PCS) sieved to − 45 µm were incorporated into polyvinyl chloride (PVC) matrix towards improving the properties of PVC composite for ceiling boards and insulating pipes which sags and degrade with time needing improvement in properties. The process was carried out via compression moulding applying 0.2 kPa pressure and carried out at a temperature of 170 °C. Composites developed were grouped according to their composition. Groups A, B, C, and D were infused with 2, 4, 6 and 8 wt% PCS at constant amount, respectively. Each group was intermixed with a varying proportions of BF (0–30 wt% at 5% interval). Tests carried out on the samples produced revealed that the yield strength, modulus of elasticity, flexural strength, modulus of rupture were enhanced with increasing BF proportion from 0 to 30 wt% BF at 2 wt% constant PCS input. Thermal and electrical properties trended downward as the fiber content reduced even as the hardness was enhanced with PCS/BF intermix which was also reflected in the wear loss index. Impact strength was highest on the infix of 4 wt% PCS and 15 wt% BF. Compressive strength was better boasted with increasing fiber and PCS amount but 8 wt% PCS amounted to depreciation in trend. It was generally observed that PCS performed optimally at 2 wt% incorporation while beyond that resulted in lowering of strength. Blending of the two variable inputs; 0–30 wt% BF and 2 wt% PCS presented better enhancement in properties.

This study reports the effect of fine sand addition on the properties of fired clay bricks. Fine sand was sieved to −75 μm and incorporated at varied weight proportions (5, 10, 15, 20, 25,...

It has been established over the years that Nickel-based superalloys are very difficult to manufacture as a result of the combination of various elemental composition. In this study, elemental powders of Ni-9Fe-22Cr-10Co wt.% superalloys were synthesized via spark plasma sintering technique at sintering temperatures ranging from 850 to 1100 °C with holding time, heating rate and pressure of 5 min, 50 °C/min and 50 MPa. The microstructural analyses were performed using an optical microscopy and scanning electron microscopy equipped with energy dispersive spectroscopy, while phase analyses were carried out using X-ray diffractometry. The potentiodynamic polarization tests were performed in 1M H2SO4 solution at ambient temperature. Results obtained show that the densification of the alloys increased with increasing sintering temperature with optimum results obtained at a sintered temperature of 1000 °C corresponding to sintered density of 98%. Furthermore, the morphologies of the sintered compacts reveal homogenous dispersion of elemental composition with less morphological defects obtained at 1000 °C. For corrosion analysis, all sintered samples display passivation region with few fluctuations. However, sample sintered at the 1000 °C yielded more stable passivity with corrosion rate of 0.0181 mm/year.

One of the uses of particle board is in the design of speaker/woofer casing, but with increasing demand, the cost is skyrocketing, effects of which lead to the high cost of end-use woofer gadgets. Cement–paper composite reinforced with snail shell powder/banana fiber was developed as an alternative. The fiber was grouped into two; untreated banana fiber (UBF) and treated banana fiber (TBF) (treated with 1 M NaOH). Fibers were infused into the composite at 0%, 0.5%, 1%, 1.5%, 2%, and 2.5% by weight of paper pulp while snail shell powder was added at 15 wt.% constant proportion for all samples produced. Curing was carried out for 28 and 56 days, respectively. The composite boards produced were examined for physical, mechanical, and microstructural properties. Results obtained indicated an uptrend in water absorption and thickness swelling at increasing fiber loading. Internal bond strength, screw holding strength, moduli of rupture, and elasticity were observed to be enhanced with increment in fiber proportion. It was further noticed that alkaline TBF performed better than the untreated fiber, hence recommended for paperboard production. Experimental trend and performance analysis engaged in revealed hydration to be the most efficient experimental variable and important for overall property maximization in cement–paper composite. Performance evaluation conducted showed effective property index was noticed to be highest for composite board doped with 2.5 wt.% TBF.

The use of chromate conversion coatings have been limited by several protocols as a result of their carcinogenicity and toxicity towards humans and the environment. Searches are ongoing for chromate replacement in coating baths and processes. This paper describes the comparison among the corrosion rates of a novel hybrid conversion coating derived from water extracts of hibiscus sabdariffa calyx in conjunction with ammonium molybdate, a molybdate conversion coating and the so-called chromate conversion coating. Potentiodynamic polarization measurement in 3.5 ​wt% sodium chloride solution was employed in ranking the coatings as sabdariffa molybdate being more corrosion resistant than chromate, which in turn out performed molybdate.

This study evaluates the effect of treated and untreated jute fiber/eggshell particulate reinforced cement-paper matrix composites for ceiling board application. Treated jute fiber (TJF) was obtained by immersing untreated jute fiber (UJF) into 1.25 M sodium hydroxide (NaOH) solution in a shaker water bath maintained at 40 °C for 4 h. Eggshells (ESP) were pulverized and sieved to -75μm. Samples were prepared by varying the fiber volume fraction from 0.5 to 2.5 wt.% in the composites. While other constituents such as the binder (cement) and eggshell were kept constant. An hydraulic press cold compaction molder was utilized in the production of the hybrid composites in a predetermined mix ratio designed based on previous research. The samples produced were cured for 7 and 14 days, then sundried for 36 h. The physical, thermal, mechanical and wear behaviour of the produced composites were evaluated while the surface morphology of the fractured splitting tensile samples were analyzed. The result reveals that TJF/ESP hybrid composites had better performance than UJF/ESP hybrid composites in most of the tests carried out. Increase in the number of curing days was found to also enhance the properties of the composite produced in majority of the test evaluated. The 0.5 wt.% UJF/ESP gave the least performance of all the composites developed. While 2.5 wt. % TJF/ESP showed an optimum properties among the composites tested. When compared with standard, it is concluded that the hybrid composites developed can be suitable for ceiling boards and also find possible application in wall partitioning., Civil engineering; Mechanical engineering; Materials Science; Construction Engineering; Concrete Technology; Materials Application; Materials Characterization; Materials Processing; Materials Safety; Materials Synthesis; Hybrid composites; Untreated jute fiber (UJF); Treated jute fiber (TJF); Eggshell (ESP); thermal; mechanical and wear behaviour

Quenching is one of the major processes of heat treatment of medium carbon steel that aims at improving its mechanical properties. However, the effectiveness of this process is dependent on several control factors that must be maximized to obtain optimum results in terms of hardness, yield strength, ultimate tensile strength among others. This study aims at optimizing the process of improving the mechanical properties of medium carbon steel by varying some key factors like the quenchant used (A), heat treatment temperature (B), and soaking time (C). The measured responses in this study were the hardness, yield strength (YS), and ultimate tensile strength (UTS). Optimization was conducted in two stages. The first stage dealt with the mono-optimization of process parameters using Taguchi's Signal-to-Noise (S/N) ratio. A total of nine (9) experiments were performed based on standard L9 orthogonal array because each of the three control factors has three (3) levels. The second stage was multi-objective optimization using Taguchi-based grey relational analysis (GRA). The optimal conditions for hardness, YS, and UTS were obtained at A2B3C3, A3B2C3, and A3B3C3, respectively. Using ANOVA as statistical analysis, it was observed that the soaking time was the main control factor for all three measured responses (31.95% contribution ratio for hardness, 62.46%, and 66.76% for YS and UTS, respectively), while the quenchant had the least contribution. Analysis of the Taguchi-based GRA revealed that the results obtained are in total conformance to that of the Taguchi method, with soaking time having the highest contribution ratio of 69.41%., Industrial engineering; Materials science; Mechanical engineering; Metallurgical process; Heat treatment; Taguchi method; Optimization; Quenchant; Signal-to-Noise ratio; Carbon steel.

This research paper demonstrates the application of Taguchi method and Response surface Methodology (RSM) for optimization of alloyed depth in laser alloying of AISI 422 martensitic stainless steel. The experiment was designed and carried out on the basis of standard L9 Taguchi’s orthogonal array in which three laser processing parameters such as laser power, scanning speed and powder feed rate were arranged at three levels. The processing parameters played an important role in the quality of alloyed coating produced and proper control of these processing parameters resulted in quality alloyed depth and hardness property. From the analysis of mean values of variance (ANOVA) and response surface numerical analysis, the significant laser processing parameters were indentified. The results showed that laser power and scanning speed are the most significant parameters affecting the alloyed depth of laser surface alloying (LSA), while the influence of powder feed rate is much minimal.