Carbon substrate is a pivotal factor influencing polyhydroxyalkanoate (PHA) properties of varied industrial importance. Three synthetic sucrose samples with varying manufacturing purity levels were selected as carbon substrates to synthesize diverse PHAs using a wild-type Bacillus cereus AAR-1. Comparative monomeric analyses of the extracted biopolymers revealed Poly (3-hydroxytetradecanoate) (P3HTD), Poly(3-hydroxybutyrate-co-2-hydroxytetradecanoate) [P(3HB-co-2HTD)], and Poly(3-hydroxybutyrate) (P3HB) with carbon elemental contents that ranged from 39 to 53 % and no nitrogen detected. The decomposition temperature of [P(3HB-co-2HTD)] was 279 degrees C, indicating higher thermal stability than the individual monomeric units. Notably, the homopolymer P3HTD exhibited an increased melting temperature of 172.4 degrees C and a reduced crystallinity percentage (X-c % = 20.7 %), crucial properties for bioplastics and medical sector applications. All the biopolymers displayed a low specific heat capacity ranging between 0.03 and 0.05 J/g degrees C, suitable for applications such as thermal storage materials and temperature-regulating textiles. The results suggest that different carbon purity grades influenced homopolymer accumulated in Bacillus cereus AAR-1.

Adding value to waste using environmental biotechnological approaches is a promising concept for its management. Mixed culture fermentation is the way of utilizing two or more microorganisms as biocatalyst to produce valuable products from various substrates, including wastes. Mixed culture fermentation could become an excellent alternative to traditional pure culture-based biotechnology to enable next generation biofuels and bio-commodity production. This caters the advantages over application of pure cultures, such as better utilization of the substrate, waste utilization, wider range of enzymes, ability to attack and convert greater variety of compounds, higher growth rates and product yield, multistep transformations in a single bioreactor and protection against unwanted contaminants. This chapter highlights some of the important and recent developments in bio-catalysis 270based on mixed microbial cultures for biofuel production with a special focus on understanding various factors that affect the metabolic pathways of mixed cultures fermentation for biofuel production such as ethanol, butanol, syngas, methane, and hydrogen. The chapter also reviews the technical constraints of the mixed fermentation process for practical and commercial applications, and applications of genetic engineering and nanotechnology tools for improving the mixed culture technology.

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.

The use of corrosion inhibitors is a major practical method for reducing the corrosion of mild steel in corrosive environments. Weight loss, potentiodynamic polarization (electrochemical) measurements and SEM analyses were used to examine the corrosion inhibition behaviour of calf thymus gland DNA (CTGDNA) in 10

Ternary bio-adsorbent was synthesized by using sisal fiber as a base with the integration of conductive polymer; polyaniline (PANI), supported with zero-valent iron nanoparticles by chemical activation with potassium hydroxide. The activation temperature impact on adsorption properties of Sisal fiber composite activated carbon was studied. The activation temperatures had a major effect on adsorption process as 100 1/n_F demonstrated that the adsorption data does not match with Freundlich model for chemisorption. The pseudo second order and Elovich kinetics correlation coefficients for the retention of Fe and Cd to solid-phase interface at SF-800/NP/PANI (C) offered a better correlation for the bio-adsorption of Fe and Cd than pseudo first order kinetic. However, the pseudo second order kinetic attained a surpassing interaction for the bio-adsorption of Fe (0.989) than Cd (0.966); while the Elovich kinetic attained a surpassing interaction for the bio-adsorption of Cd (0.975) than Fe (0.945). The recovery and recycling stability of the bio-adsorbent composites were studied.

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.

The industrialization in Lagos State has impacted the Ibeshe watershed, as a result, lower water quality is being experienced. Hence, a novel way on the potential use of waste to treat Ibeshe watershed by synthesizing of graphene oxide and incorporating it into PET bottle waste membranes was studied. Polyethylene terephthalate (PET) membranes embedded with 1wt%, 2wt%, and 3wt% graphene oxide (GO) (M1, M2, and M3), were prepared via non-solvent-induced phase separation on polyester nonwoven support with the use of polyethylene glycol (PEG) as an additive. The surface morphologies of the three membranes appeared to be considerably different. The pore volume steadily reduces with an upsurge in the quantity of GO embedded in the membranes. A statistical assessment employing a uniform distribution curve was done using Python and the outcomes depict that the distribution of the radius data was firmly gathered around the mean. From the adsorption study, Fe2+ does not have the power to attract HCO3− in the transitory state at the surface of the membrane; hence HCO3− could not reach equilibrium at 80 min. The membranes’ performance was studied via flux and the rejection of iron and anions. The rejection rate calculated for the three anions and iron was observed to be high in the M3 membrane. The M3 membrane% rejection of the anions and iron is 96%, 85%%, 72%, and 60% for NO3−, Cl−, HCO3− and Fe, respectively. An upsurge in the amount of GO improved the water flux; hence, 3wt% GO gave the maximum water flux.

In the past few years many corrosion inhibitors research has been oriented towards eco-friendly extracts from plants. In this research cassava (Manihot esculenta) leaf Deoxyribonucleic acid (DNA) was extracted as green inhibitor compound for low carbon steel protection from corrosion. The mechanism of inhibition was investigated in 3.5% w/v NaCl (simulating naturally aerated seawater) by weight loss, potentiodynamic polarization measurements and SEM/EDX and FTIR assessments. These measurements investigated the corrosion resistance and morphology of low carbon steel using electrochemical parameters (corrosion potential, corrosion current and corrosion rate) and gravimetric analysis (weight loss and surface coverage). The electrochemical (potentiodynamic polarization) test results showed that a concentration of 20 mg/L of DNA, inhibited the corrosion of low carbon steel in 3.5% w/v NaCl with an inhibition efficiency of 96.4%. Inhibition efficiency of 88.37% from weight-loss measurements after immersion in the test solution for 240 hours were obtained as well. Potentiodynamic polarization tests plots demonstrated that DNA is a mixed inhibitor; it reduces both cathodic and anodic reactions by forming films on the surface of mild steel. The adsorption model of DNA corresponds to the Langmuir isotherm. This demonstrated the suitability of cassava leaf DNA as an inhibitor of mild steel corrosion for saline environment.

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.

Increasing the yield of Gasoline has been the desire of every crude oil refining process in the oil industry. The principal unit that has significantly contributed to increasing the yield of Gasoline is the Fluid Catalytic Cracking (FCC) unit. The performance of the FCC unit is dependent on many parameters, substantively the catalyst-to-oil ratio (COR) and the temperature of the catalyst (tcat) when entering the riser reactor. To understand the effect of COR and tcat, a five-lump kinetics model was developed, and the simulated result was further plugged into MINITAB 7.0 software in order to generate a set of empirical equation models. The empirical equation models predicted the optimal yield of gasoline to be 56.83%, with corresponding optimal parameters of COR and temperature of catalyst as 3.35 and 900 K, respectively. The actual yield of gasoline at 3.35 COR and 900 K catalyst temperature was 56.78%, with a 0.09% error compared to the predicted yield of gasoline. The two parameters were varied with the values from previous studies, and the predicted result compared to the actual is 7.8648 root mean square error (RMSE). Therefore, the empirical equation model is reliable in predicting the yield of gasoline with respect to the COR and temperature of catalyst.

The corrosion of CO2 is a multifaceted process. This study investigated the impact of Syzygium malaccense DNA in combating the corrosion of dissolved CO2 in water on mild steel. The increase in the concentration of CO2 and of course the carbonic acid increases the corrosion rate of mild steel by speeding up the cathodic reaction. However, with regards to inhibitor efficiency, no evidence was found for a direct reaction of CO2 on mild surface. The adsorption of Syzygium malaccense DNA inhibitor in all the concentrations of dissolved CO2 media on mild steel surfaces obeyed the Freundlich adsorption isotherm as all linear correlation coefficient (R2) values were close to 1. The inhibition mechanism was ascribed to the electrostatic interaction ensued amid the negatively charged surface of the mild steel and the positively charge DNA inhibitor molecule. All surfaces of tested samples were characterized by XRD and SEM. The 0 mg/L DNA in 1627 mg/L dissolved CO2 led to formation of high rough surface. The XRD patterns depict that the mild steel mainly constitutes Fe and FeCO3.

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).

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.

Chemical kinetics and thermodynamics provide modes and mechanisms for the thermal death of microbial spores. In this study, the effect of thermal inactivation on Geobacillus stearothermophilus, a highly heat-resistant bacterial species, was studied over the temperature range of 95, 100, 105, and 110 °C and holding sterilization periods of 10, 15, 20, 25, 30, and 45 min by the application of mathematical analysis of kinetic and thermodynamic properties. Thermal death rate constant, k, for the best kinetic order of sterilization ranged between 0.0431 to 0.1581 min−1 with the energy of activation, Ea, estimated to be 115.96 kJ/mol. Two primary thermal death kinetic models were applied (log-linear first order and the nonlinear Weibull). Weibull's model provided more reliable kinetic parameters to predict the effect of thermal treatments. Concave curves (α >1) were predicted with the Weibull's model for 100, 105, and 110 °C (1.57, 1.26, and 1.22 respectively), indicating the susceptibility of spores to lethal treatment. The rate parameter, ɸ (first reduction time) decreased with increasing thermal heating (28.80 min (95 °C), 21.08 min (100 °C), 14.61 min (105 °C), and 9.65 min (110 °C)) following the paths of the D-values (about 7 min to attain 88% spores' destruction after 110 °C heating) of the log-linear kinetic model. Thermal death time (TDT) for the complete destruction of spores was predicted to be after 40 min at 110 °C. The z-value was 23.31 °C, indicating the sterilization temperature that must be attained for one log destruction of spores. The heat of activation showed endothermic reactions for all temperatures (∆H ranged 112.90 – 112.78 kJ/mol), Gibb's free energy of activation, ∆G, ranged from 325 – 333.74 kJ/mol (indicating a non-spontaneous reaction), and the entropy of activation (∆S) showed reversibility of reaction (∆S < 1) for all the thermal temperatures.

The Southwest Nigeria has witnessed tremendous increase in the output of municipal wastes in the recent years. Non availability of government policy on solid wastes management or its lack of effectiveness where it exists makes unabated open burning the predominant means of municipal solid waste disposal in the region. Open burning of municipal wastes being a major source of anthropogenic air emissions was investigated for atmospheric loading of some hazardous organic pollutants using the emission inventory method. The specific pollutants considered in this study were volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxin (PCDDs) and polychlorinated dibenzo furan (PCDF). The estimated release of VOCs, PAHs, PCBs, PCDD and PCDF from open burning of municipal wastes in the region over the 5-year period investigated were 64000 tonnes, 988 tonnes, 43 tonnes, 0.56 tonnes and 0.2 tonnes respectively. Given the serious human health implications associated with these hazardous organic pollutants, the study suggested conversion of wastes to energy as a possible solution since the region also faces energy challenges.

The effectiveness of grapefruit (citrus paradisi rind) peel powder as a green corrosion inhibitor on A36 mild steel in 0.5M H2SO4 was examined. Gravimetric tests, SEM-EDS, and adsorption isotherm techniques were used to determine the corrosion inhibition features of the inhibitor on the surface of A36 mild steel. The tests were carried out with variation in concentration of inhibitor (0–0.4 %w/v), corrosion temperature (301K and 318K), and corrosion time (3– 12 hours). The findings demonstrated that citrus paradisi rind powder effectively inhibited the corrosion of A36 mild steel on the surface with maximum corrosion inhibition efficiency of 85% at 0.4 w/v% inhibitor concentration at 310K corrosion temperature. The SEM-EDS analysis established the presence of sulphur, nitrogen, and oxygen (organic constituents), as well as the formation of a protective coating on the mild steel surface. Langmuir adsorption isotherm was found suitable for the prediction of the adsorption of citrus paradisi rind inhibitor on the mild steel surface. The thermodynamic considerations (∆𝐻 and (∆𝑆) indicated that the inhibition of A36 mild steel corrosion (using citrus paradisi rind inhibitor) was an exothermic process and the inhibitor molecules were physically adsorbed on the metal surface.

Biomass gasification and the production of syngas are important in the production of biohydrogen, a green fuel and an energy carrier for the fuel cell. The tool for the prediction of biohydrogen production from any biomass should be readily available to determine the viability of such biomass for gasification. The software implementing a robust gasification model is complex, proprietary, and expensive. In order to solve this problem, we developed Gasific, a software module for simple, free, and accurate biomass gasification product gas prediction. Gasific, implemented biomass gasification, stoichiometric equilibrium models, in Python and runs on a variety of platforms. We discussed the application of Gasific on biomass wastes, namely, Imperata cylindrica; the simulation shows good performance in predicting the gas composition product of gasification. The developed software and the code can be modified and applied to other scientific models and transform the models into software applications.