Background Atherosclerosis is a build-up of low-density lipoproteins (LDL) in the channels of blood vessels. This occludes the vessels and, occurring in the carotid arteries, portends conditions that favour stroke. This work is an attempt to mathematically represent the physiological process of atherosclerosis caused by plaques on the walls of the human arteries. Aim Provide insight into the effect of blood flow velocity on wall shear stress and its implications on atherosclerosis progression in a human carotid artery via computational simulation. Methods The effect of blood velocity on plaque growth and progression is simulated using COMSOL multi-physics. The human carotid was modeled in 2-D with Stokes law for model flow. The simulation began with a plaque-free vessel with velocities of 30 m/s – 125 m/s. Results Results showed that the rate of plaque initiation dropped as the blood velocity increased from 30 m/s to 125 m/s; higher inlet velocities gave lower plaque growth; the highest degree of 30% stenosis was recorded at a blood velocity of 30 m/s. Plaque height significantly affects the Plaque wall Stress, PWS, and its distribution around the plaque and arterial wall; higher plaque heights experience higher velocity distribution around the plaque, causing a higher force associated with blood flow around the plaque, resulting in higher compression stress. More compressional stresses are localized around the root, which would encourage growth as well as possible rupture at higher velocities. These ruptured plaques potentially narrow or block the arteries and prevent blood flow. This is atherosclerosis and can lead to a heart attack. Conclusion Results from this study can find significant use in the understanding, management, and treatment of atherosclerosis since the regulation of blood velocity and pressure plays a major role in the progress of atherosclerosis in the carotid artery which raises the risk of stroke.

Clean fuel and sustainable energy utilization are essential requirements to address the impacts of global warming and climate change. In this study, the pyrolysis of motor car scrap tire was investigated in a fabricated cylindrical stainless steel reactor, operated at 450, 500, and 550 °C for 50 min with or without catalytic. The catalytic condition yielded maximum char of 59%w/w obtained at 450 °C. The addition of the catalyst also enhanced oil yield up to 33%w/w at 500 °C while the maximum gas fraction of 44%w/w was obtained under the non-catalytic condition, at 550 °C. The TGA/DSC analysis showed that the pyrolysis char had a specific heat capacity (Cp) of 35 J/g.K, relating to its high thermal stability for applications in furnaces as fuels, reactors, and heat construction materials. The char, after chemical activation, with the XRD analysis, showed that the produced activated carbon (AC) have good crystalline structure (with high interplanar distances). The BET analysis revealed that the AC had a high surface area of 1065 m2/g (average pore diameter of 3.36 nm) which enhanced the adsorption capacity of the AC to about 90% efficiency for the removal of heavy metal, cadmium, from sugar mill wastewater.

With the increasingly widespread use of polyethylene terephthalate (PET) bottles due to their cheap and robust nature, there has been an exponential increase in waste from these bottles in landfills, dumpsites, gutters, and roadsides, which has led to a negative effect on the environment, plants, animals, and human population with land and water pollution. Chemical recycling of the waste PET bottles would reduce the menace and recover the starting monomers for PET production. In this research, waste PET bottles were chemically recycled through glycolysis to produce bis-hydroxyethyl terephthalate (BHET) using ethyl glycol (EG) as a solvent and calcined snail shell as a catalyst within the temperature range of 180-200°C at different EG:PET ratios of 5:1, 6:1, and 6.5:1, while a constant catalyst:PET of 1:100 was used. After reaction and crystallization, a yield of the glycolysis product of 39.72% was obtained. This yield recorded is not as good as using oyster shell (68.6%), sodium acetate (72%), and calcium carbonate (69%) as catalysts. TGA and FTIR indicated that the samples were composed mainly of BHET monomers as functional groups. It is recommended that longer reaction time and varying catalyst:PET ratio be used to determine the optimum temperature and reaction. Keywords: Glycolysis, Bis-Hydroxyethyl Terephthalate, Chemical Recycling, Polyethylene Terephthalate Depolymerization, Snail Shell DOI： https://doi.org/10.35741/issn.0258-2724.58.3.28

Mono-component adsorption of Co2+ ions from simulated industrial water was investigated by using cow bone (CB), cow bone char (CBC), and activated cow bone carbon (ACBC) adsorbents synthesized from raw cow bone as the precursor. The resulting prepared adsorbent materials were then characterized using analytical methods such as: zeta potential measurements, BET surface area, FTIR, SEM, EDS, and XRD analysis. For all synthesized adsorbents, the main compositions were mesopores with the presence of C--C, PO32 , CO32 and O-H bonds signifying hydroxyapatite nature of the adsorbents. The isoelectric point (pHIEP) of ACBC was obtained to be 3.59 (lowest among the prepared adsorbents) thereby signifying that ACBC's electrostatic force of attraction was relatively higher between the Co2+ and its surface. The study showed that the pseudo second-order kinetic model had the best correlation for all the adsorption kinetic experimental data for each prepared adsorbent, inferring that the rate-controlling step during the Co2+ ions adsorption onto the prepared adsorbents is chemisorption. The Sips isotherm model excellently predicted the adsorption data for the adsorption of Co2+ ions on the CB adsorbents while the Langmuir isotherm best fitted the equilibrium data of the CBC, and ACBC prepared adsorbents with excellent correlation coefficients, while maximum adsorption capacities, qmax, were obtained to be 52.50, 58.80, and 64.50 mg g-1 for CB, CBC, and ACBC respectively. The study of the thermodynamic properties of the adsorption of Co2+ showed the process was endothermic, non-spontaneous and endogenic for the ACBC adsorbent, while being exothermic for the CB, and CBC adsorbents in addition to having physisorption properties.

Flat thin-film magnesium oxide-chitosan nanocomposite membranes were synthesized with polyethylene terephthalate (PET) and employed for natural gas dehydration. The water vapor permeation was most pronounced with a nanocomposite membrane doped with 0.9 g MgO nanoparticles (NP) as a result of a significant upsurge in the permeability of water vapor in the membrane (0.87). With the increase in MgO NP, large macro-voids are created, substratum pore size, and thickness together with the water vapor permeation were upsurged. The dehydration of natural gas performance of magnesium oxide-chitosan nanocomposite membranes synthesized with PET was enhanced with the increase in MgO NP embedded in the membrane. Though water vapor permeation was restricted by the polyester non-woven material used as a support for the nano composite membranes, as the three membranes did not reach the permeation coefficient of 1. However, the permeation coefficient increased with an increased MgO NP, with three mambrane samples (M1, M2 and M3) having permeation coefficient of 0.763, 0.77 and 0.87 respectively. The gas reduced with an increase MgO NP, with M1, M2 and M3 having 3.46×10−2, 3.17×10−2 and 3.88×10−3 kg/m3 respectively. From the adsorption study, the discrepancy observed between CH4 and vapor with isotherm models was ascribed to the different adsorption behavior of CH4 and vapor on the membrane-active area. The cost of making the membrane cannot be considered as a terminal criterion because most of the cost-effective option is not always the optimum one. The membranes confirmed their suitability for the dehydration of natural gas.

The thermal transformation of lignocelluloses is important because energy is required. The drying process is unique during this transformation. In this study, gravimetric analysis was applied in determining the effective moisture diffusivity and the kinetic parameters for the drying process of cassava stalk lignocellulosic biomass. The drying process was evaluated on the biomass at temperatures 80, 100, and 120 °C from 0 to 8 h using time interval of 0.5 h. The effective moisture diffusivities, Deff, varied from 1.63 × 10−11 m2/s (80 °C) to 2.56 × 10−11 m2/s (120 °C). The activation energy (Ea) during the drying process estimated at the three chosen temperatures was calculated to be 12.93 kJ/mole with a pre-exponential factor, Do, of 1.30 × 10−9 m2/s. Based on statistical analysis (coefficient of determination and average absolute error), the experimental data best fit was provided by the Midilli-Kucuk mathematical model when compared with the other two drying models (Page and Newton).

The red kidney beans found in the Esanland of Edo State, Nigeria, popularly known as Ikpakpa, are a variety of Phaseolus vulgaris. However, a lack of awareness about this indigenous legume and a lack of easy culinary applications are factors that lead to its low use. The very long hours of cooking, coupled with frequent changing of the cooking water, makes it very unattractive to the present generation. In this work, a novel attempt is made to have a culinary product from ikpakpa via spontaneous and controlled fermentation of the beans (Ikpakpa) and investigate their impact on the product’s nutritional value. Endogeneous microorganisms were used for spontaneous fermentation, while Bacillus subtilis was used for the control fermentation. Two routes of Ikpakpa preparation were followed: viz; beans were boiled for 8 hours to be soft, dehulled, and fermented; and the raw beans soaked overnight and dehulled, boiled for 4 hours fermented. After 5 days of fermentation, the proximate analysis results showed better results for the spontaneous fermentation via route 1, increasing protein and carbohydrate content by 18% and 36%, respectively. Both spontaneous and controlled fermentation were not favoured via route 2 as a decrease in protein and carbohydrate content by 13.5%/77.4% and 54.2%/66,4%, respectively. The duration for fermentation may have been too long to sustain the protein and carbohydrate content. It is, therefore, recommended that more research on the optimal fermentation duration be investigated and shelf-life studies conducted on the products.

Introduction: Cardiovascular diseases are a known health threat with no respect for age. The need to understand the initiation and progress of the disease is expedient in proper diagnosis and management of the disease. Objective: The work is targeted at simulating the effect of elevated blood pressure on the initiation and development of plaque over time concerning wall shear stress, WSS and plaque wall stress, and PWS. Methods: Conditions such as blood velocity, pressure, and arterial wall conditions associated with blood flow in arteries, as well as patient-specific characterization related to these variables and conditions, were plugged into modified models in the COMSOL multiphysics software. The artery was modeled as an idealized 2-D carotid artery model. Results: Results showed that the WSS distribution with respect to changes with a blood pressure of 500 Pa gave the highest WSS value at the plaque neck and 1500 Pa gave the highest WSS value in the regions close to the plaque root. It was also observed that as the plaque size increased, the region experiencing severely high values for WSS also expanded. Conclusion: It can be recommended that blood pressure monitoring is necessary to curb the attendant cardiovascular diseases associated with high blood pressure.

In this review, insight is given on the effect of wall shear stress (WSS) on the initiation and progression of plaque growth in micro-circulation by using mathematical models. The understanding of the trigger for the initiation and progression of the disease has improved over the years and has led to better models for describing the process. Models have been developed and tested in order to describe haemodynamic properties in blood vessels to accurately simulate the process. The Navier-Stokes equation is the backbone model for all computational fluid dynamic simulation and applications, which has found foundational importance in simulations related to atherosclerosis studies. The risk factors associated with the disease are discussed. The rheological models associated with blood are analyzed and compared with studies that have been carried out in the past. A systematic review of the major findings of the simulation results has been brought afore, with a focus on wall shear stress (WSS), degrees of stenosis and plaque growth. It was concluded that the current studies are not holistic enough to give insight into the pathophysiology of the disease. Recommendations on how further studies should be done to improve the knowledge gap in this subject matter were proposed.

Research effort is being intensified on the establishment of organic substances that can actively perform the role of metal inhibition. Investigation on corrosion inhibition of A36 mild steel in 0.5 M H2SO4 medium using waste citrus limonum peels as inhibitor was carried out. Gravimetric tests (weight loss, corrosion rate and inhibition efficiency) involving the variation of citrus limonum peels inhibitor concentration (0–4 w/v%), corrosion time (0–12 h) and reaction temperature (28 °C and 45 °C) were conducted. Langmuir and Freundlich adsorption isotherms were considered in the establishment of the adsorption behavior of citrus limonum peels inhibitor on A36 mild steel surface. The thermodynamic parameters (adsorption equilibrium constant kads, change in Gibbs free energy ΔGads, change in heat of adsorption ΔHads and entropy change ΔSads) of the adsorbed inhibitor on mild steel surface were determined. The results of the study showed that 0.4 w/v% citrus limonum concentration gave highest inhibition efficiency of 94% and 92% on A36 mild steel at 28 °C and 45 °C respectively. And the surface adsorption of citrus limonum inhibitor on A36 mild steel was described by both the Langmuir and Freundlich adsorption isotherms. The negative values of ΔS, ΔGads, ΔHads indicated that the inhibitor adsorption is exothermic and spontaneous (physical adsorption). SEM/EDX analysis showed that inhibitor adsorption of citrus limonum was better at 28 °C compare to 45 °C, by giving a more evenly distributed particles at 0.4 w/v% inhibitor concentration.

Laser cladding is a growing technological method that utilizes a navigating high power laser for melting a small region of the substrate; it has a function of trapping and melting entering powder particles. Hence, the process leads to the development of a new stratum. Aluminum alloy Matrix composites afford properties suchlike high wear resistance, high tensile strength, lightweight; this composites is finding wide applications in automotive industry. This review presents a brief discussion on laser cladding for aluminum base alloys for automotive industry with emphasis on aluminum alloys matrix composite for automotive industry.

As part of the efforts in attaining the commercialisation of biodiesel production in Nigeria, this research work considers a pilot plant design for the production of 1kg biodiesel, using waste soybean oil (WSO). CHEMCAD 7.1.2 software was utilised for the plant design and the process flow diagram revealed that four (4) pumps, four (4) heaters, two (2) separators, one (1) drying equipment and two (2) reactors were involved. Also, the simplified and simulated 1kg biodiesel production design plant showed that 0.0513kg/hr of methanol and 0.1800kg/hr of 0.1M H2SO4 would be required during the esterification process. And 0.6921kg/hr of methanol, 0.9870kg/hr of WSO as well as 0.1880kg/hr of KOH catalyst would be required for the transesterification process. That is the results obtained serve as template for the simulation of process design plants of varied production capacities. This is a good attempt in the ease of attainment of the commercialisation of biodiesel production in Nigeria.

The contamination of soil originated from evolutional activities such as transportation and spillage, as in the case of Ogoni land in the Niger Delta area of Nigeria, and it is a well-known environmental problem in Nigeria. This study examined the capacity of two indigenous bacteria, Pseudomonas aeruginosa, and Bacillus subtilis to remediate the hydrocarbon contaminated soil. The focus of the work was to isolate, identify, and determine the extent of bioremediation achieved in the soil contaminated with crude oil in Ogoni land, which was used as a case study for the slurry-phase bioremediation process. These organisms earlier mentioned were identified based on their morphological and biochemical characteristics. The bacteria species were considered separately and in combination in a Laboratory-scale slurry-phase in a 14-day treatment period using 30 g of soil for each case. The performance of each batch bioreactor was compared to the sterile control. The slurry phase bio-reactor, R A , treated with Pseudomonas sp., had an actual degradation of 31%, the slurry phase bio-reactor, R B , treated with Bacillus sp., had a real degradation of 35%. The slurry phase bio-reactor Rc, which contain both microorganisms had an actual degradation of 36%, the slurry phase bio-reactor R D had a real degradation of 0%. The results obtained confirm that the isolated bacterial from the soil can effectively utilize contaminating crude oil as a source of carbon and energy. The decrease of hydrocarbon in the sterile control was used as a basis for comparison of the petroleum hydrocarbons lost through the extraction process as microbiological activity was not possible. Results from the study have shown that P. aeruginosa and B. subtilis strains were effective for the slurry-phase bioremediation of hydrocarbon contaminated soil.

Cassava starch and expanded polystyrene [EP] (Styrofoam) were collected and converted into adhesives.Two starch-based glue were produced from the hydrolysis and dexrination of cassava starch, while the expanded polystyrene was formulated through the dissolution of the solid in benzene.The produced adhesives were tested based on their bonding capacity using four substances: thermoplastic cup, plywood, garden hose and papers.The Expanded polystyrene glue could form bonds with all four materials.The tack/drying time was also recorded during the bonding moments.The rheological properties of the formulated adhesives were studied and it was seen that the glues produced showed properties of a shear-thinning/ pseudo-plastic fluid.

The bleaching process is a crucial process in palm oil refining in which an adsorbent is majorly used to adsorb the unwanted colour pigments and a wide range of other impurities. Groundnut hull was collected and processed into powder form as Groundnut hull powder [GHP], the powder was used to remove the colour pigments and other minor impurities from crude palm oil. Free fatty acid (FFA) analysis was carried out on the palm oil before and after bleaching. The effects of three factors: temperatures, mass and time were investigated on the response. Central Composite Design [CCD] employed resulted in 20 runs. The conducted analysis has shown that groundnut hull was able to reduce FFA composition as well as reduce the colour of the palm oil to a desired colour.

Land form, management policy and socio-economic characteristics have been identified as factors responsible for poor solid waste management. This study examined the influence of livelihood assets on waste sanitation/disposal behaviour in Lagos Metropolis: a case study of Okobaba. A multi-stage sampling procedure was used to obtain data for analysis. From the data collected and analyzed descriptively, efforts were made to identify and examine the respondents’ socio-economic characteristics, waste sanitation characteristic, livelihood assets and the connection between livelihood assets and waste sanitation behaviour of people in the area under study. The research result established the existence of variations in the waste disposal characteristics of respondents in the area under study. Therefore, it is recommended that a deliberate policy to provide livelihood assets or conditions that will improve access to better livelihood capacity, adequate for low-income households to meet their basic psychological livelihood needs. This is imperative in ensuring attitudinal change towards waste management and advancement to a second-order need like environmental sanitation.

Globally, environmental challenges have been recognised as a matter of concern. Among these challenges are the reduced availability and quality of drinking water, and greenhouse gases that give rise to change in climate by entrapping heat, which result in respirational illness from smog and air pollution. Globally, the rate of demand for the use of freshwater has outgrown the rate of population increase; as the rapid growth in town and cities place a huge pressure on neighbouring water resources. Besides, the rapid growth in anthropogenic activities, such as the generation of energy and its conveyance, release carbon dioxide and other greenhouse gases, warming the planet. Polymer nanocomposite has played a significant role in finding solutions to current environmental problems. It has found interest due to its high potential for the reduction of gas emission, and elimination of pollutants, heavy metals, dyes, and oil in wastewater. The revolution of integrating developed novel nanomaterials such as nanoparticles, carbon nanotubes, nanofibers and activated carbon, in polymers, have instigated revitalizing and favourable inventive nanotechnologies for the treatment of wastewater and gas separation. This review discusses the effective employment of polymer nanocomposites for environmental utilizations. Polymer nanocomposite membranes for wastewater treatment and gas separation were reviewed together with their mechanisms. The use of polymer nanocomposites as an adsorbent for toxic metals ions removal and an adsorbent for dye removal were also discussed, together with the mechanism of the adsorption process. Patents in the utilization of innovative polymeric nanocomposite membranes for environmental utilizations were discussed.

In this research work, a simple design for the production of 1kg biodiesel involving two stage esterification-transesterification process, with the use of waste soybean oil (WSO) and NaOH catalyst was considered. CHEMCAD 7.1.2 software was used for the design operation which revealed that four (4) pumps, four (4) heaters, two (2) mixers, one (1) drying equipment and two (2) reactors were involved. Also, the production process design revealed that 0.0513kg/hr of methanol and 0.1800kg/hr of 0.1M H2SO4 were required during the esterification process. While 0.6921kg/hr of methanol, 0.9870kg/hr of WSO as well as 0.1934kg/hr of NaOH catalyst were needed for the transesterification process. The simplicity of the design and high purity level of the biodiesel produced adjudged the design operation good.

The use of Moringa oleifera seed in water purification has reduced the use of chemical-based coagulants which is detrimental to both human and livestock. This project aimed at testing the microbial properties of M. oleifera seed oil extract on some selected pathogens (Bacterial and fungi). The oil was extracted using Soxhlet apparatus with ethanol as solvents. Gas-chromatography-mass spectrometry (GCMS) analyses were carried out for the identification of active components in the oil extract. The zone of inhibition test carried out showed that this particular plant seed oil extract has antifungal property with Candida albicans and Rizopus stolonifera with highest zone of inhibition. The raffinate was used for water purification and the oil for the production of an antifungal soap.